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Sample records for cell polarization reproduces

  1. Design of reproducible polarized and non-polarized edge filters using genetic algorithm

    International Nuclear Information System (INIS)

    Recent advancement in optical fibre communications technology is partly due to the advancement of optical thin film technology. The advancement of optical thin film technology includes the development of new and existing optical filter design methods. The genetic algorithm is one of the new design methods that show promising results in designing a number of complicated design specifications. It is the finding of this study that the genetic algorithm design method, through its optimization capability, can give more reliable and reproducible designs of any specifications. The design method in this study optimizes the thickness of each layer to get to the best possible solution. Its capability and unavoidable limitations in designing polarized and non-polarized edge filters from absorptive and dispersive materials is well demonstrated. It is also demonstrated that polarized and non-polarized designs from the genetic algorithm are reproducible with great success. This research has accomplished the great task of formulating a computer program using the genetic algorithm in a Matlab environment for the design of a reproducible polarized and non-polarized filters of any sort from any kind of materials

  2. Effect of surface state of type 18-10 stainless steel on the authenticity and reproducibility of potentiodynamic polarization curves

    International Nuclear Information System (INIS)

    The effect of mechanic and electrochemical methods of finishing the surface of the 18-10 stainless steel (polishing, electropolishing) and its oxidation in air at room temperature on the authenticity and reproducibility of anode polarization curves is investigated. It is established that the behaviour of anode potentiodynamic polarization curves, both in active and passive range of potentials, depends on microgeometry and on the oxidation degree of initial electrode surface as well. An optimal method of preparing surfaces of the 18-10 steel for polarization measurements is suggested

  3. Wnt-Dependent Control of Cell Polarity in Cultured Cells.

    Science.gov (United States)

    Runkle, Kristin B; Witze, Eric S

    2016-01-01

    The secreted ligand Wnt5a regulates cell polarity and polarized cell movement during development by signaling through the poorly defined noncanonical Wnt pathway. Cell polarity regulates most aspects of cell behavior including the organization of apical/basolateral membrane domains of epithelial cells, polarized cell divisions along a directional plane, and front rear polarity during cell migration. These characteristics of cell polarity allow coordinated cell movements required for tissue formation and organogenesis during embryonic development. Genetic model organisms have been used to identify multiple signaling pathways including Wnt5a that are required to establish cell polarity and regulate polarized cell behavior. However, the downstream signaling events that regulate these complex cellular processes are still poorly understood. The methods below describe assays to study Wnt5a-induced cell polarity in cultured cells, which may facilitate our understanding of these complex signaling pathways. PMID:27590152

  4. Reproducible isolation of lymph node stromal cells reveals site-dependent differences in fibroblastic reticular cells

    Directory of Open Access Journals (Sweden)

    Anne L Fletcher

    2011-09-01

    Full Text Available Within lymph nodes, non-hematopoietic stromal cells organize and interact with leukocytes in an immunologically important manner. In addition to organizing T and B cell segregation and expressing lymphocyte survival factors, several recent studies have shown that lymph node stromal cells shape the naïve T cell repertoire, expressing self-antigens which delete self-reactive T cells in a unique and non-redundant fashion. A fundamental role in peripheral tolerance, in addition to an otherwise extensive functional portfolio, necessitates closer study of lymph node stromal cell subsets using modern immunological techniques; however this has not routinely been possible in the field, due to difficulties reproducibly isolating these rare subsets. Techniques were therefore developed for successful ex vivo and in vitro manipulation and characterization of lymph node stroma. Here we discuss and validate these techniques in mice and humans, and apply them to address several unanswered questions regarding lymph node composition. We explored the steady-state stromal composition of lymph nodes isolated from mice and humans, and found that marginal reticular cells and lymphatic endothelial cells required lymphocytes for their normal maturation in mice. We also report alterations in the proportion and number of fibroblastic reticular cells (FRCs between skin-draining and mesenteric lymph nodes. Similarly, transcriptional profiling of FRCs revealed changes in cytokine production from these sites. Together, these methods permit highly reproducible stromal cell isolation, sorting, and culture.

  5. Coronavirus infection of polarized epithelial cells

    NARCIS (Netherlands)

    Rossen, J W; Horzinek, M C; Rottier, P J

    1995-01-01

    Epithelial cells are the first host cells to be infected by incoming c oronaviruses. Recent observations in vitro show that coronaviruses are released from a specific side of these polarized cells, and this polarized release might be important for the spread of the infection in vivo. Mechanisms for

  6. Membrane Organization and Dynamics in Cell Polarity

    OpenAIRE

    Orlando, Kelly; Guo, Wei

    2009-01-01

    The establishment and maintenance of cell polarity is important to a wide range of biological processes ranging from chemotaxis to embryogenesis. An essential feature of cell polarity is the asymmetric organization of proteins and lipids in the plasma membrane. In this article, we discuss how polarity regulators such as small GTP-binding proteins and phospholipids spatially and kinetically control vesicular trafficking and membrane organization. Conversely, we discuss how membrane trafficking...

  7. Minimal model for spontaneous cell polarization and edge activity in oscillating, rotating and migrating cells

    Science.gov (United States)

    Raynaud, Franck; Ambühl, Mark E.; Gabella, Chiara; Bornert, Alicia; Sbalzarini, Ivo F.; Meister, Jean-Jacques; Verkhovsky, Alexander B.

    2016-04-01

    How cells break symmetry and organize activity at their edges to move directionally is a fundamental question in cell biology. Physical models of cell motility commonly incorporate gradients of regulatory proteins and/or feedback from the motion itself to describe the polarization of this edge activity. These approaches, however, fail to explain cell behaviour before the onset of polarization. We use polarizing and moving fish epidermal cells as a model system to bridge the gap between cell behaviours before and after polarization. Our analysis suggests a novel and simple principle of self-organizing cell activity, in which local cell-edge dynamics depends on the distance from the cell centre, but not on the orientation with respect to the front-back axis. We validate this principle with a stochastic model that faithfully reproduces a range of cell-migration behaviours. Our findings indicate that spontaneous polarization, persistent motion and cell shape are emergent properties of the local cell-edge dynamics controlled by the distance from the cell centre.

  8. Profiling Signaling Polarity in Chemotactic Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingchun; Ding, Shi-Jian; Wang, Wei; Jacobs, Jon M.; Qian, Weijun; Moore, Ronald J.; Yang, Feng; Camp, David G.; Smith, Richard D.; Klemke, Richard L.

    2007-05-15

    While directional movement requires morphological polarization characterized by formation of a leading pseudopodium at the front and a trailing rear at the back, little is known about how protein networks are spatially integrated to regulate this process. Here, we utilize a unique pseudopodial purification system and quantitative proteomics and phosphoproteomics to map the spatial relationship of 3509 proteins and 228 distinct sites of phosphorylation in polarized cells. Networks of signaling proteins, metabolic pathways, actin regulatory proteins, and kinase-substrate cascades were found to partition to different poles of the cell including components of the Ras/ERK pathway. Also, several novel proteins were found to be differentially phosphorylated at the front or rear of polarized cells and to localize to distinct subcellular structures. Our findings provide insight into the spatial organization of signaling networks that control cell movement and provide a comprehensive profile of proteins and their sites of phosphorylation that control cell polarization.

  9. Highly Efficient Reproducible Perovskite Solar Cells Prepared by Low-Temperature Processing

    Directory of Open Access Journals (Sweden)

    Hao Hu

    2016-04-01

    Full Text Available In this work, we describe the role of the different layers in perovskite solar cells to achieve reproducible, ~16% efficient perovskite solar cells. We used a planar device architecture with PEDOT:PSS on the bottom, followed by the perovskite layer and an evaporated C60 layer before deposition of the top electrode. No high temperature annealing step is needed, which also allows processing on flexible plastic substrates. Only the optimization of all of these layers leads to highly efficient and reproducible results. In this work, we describe the effects of different processing conditions, especially the influence of the C60 top layer on the device performance.

  10. Polarized sorting and trafficking in epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Xinwang Cao; Michal A Surma; Kai Simons

    2012-01-01

    The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain,which are separated by tight junctions.The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules.This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers.Here we review the recent advances in the field of polarized sorting in epithelial cells.We especially highlight the role of lipid rafts in apical sorting.

  11. Polarized Cell Division of Chlamydia trachomatis.

    Science.gov (United States)

    Abdelrahman, Yasser; Ouellette, Scot P; Belland, Robert J; Cox, John V

    2016-08-01

    Bacterial cell division predominantly occurs by a highly conserved process, termed binary fission, that requires the bacterial homologue of tubulin, FtsZ. Other mechanisms of bacterial cell division that are independent of FtsZ are rare. Although the obligate intracellular human pathogen Chlamydia trachomatis, the leading bacterial cause of sexually transmitted infections and trachoma, lacks FtsZ, it has been assumed to divide by binary fission. We show here that Chlamydia divides by a polarized cell division process similar to the budding process of a subset of the Planctomycetes that also lack FtsZ. Prior to cell division, the major outer-membrane protein of Chlamydia is restricted to one pole of the cell, and the nascent daughter cell emerges from this pole by an asymmetric expansion of the membrane. Components of the chlamydial cell division machinery accumulate at the site of polar growth prior to the initiation of asymmetric membrane expansion and inhibitors that disrupt the polarity of C. trachomatis prevent cell division. The polarized cell division of C. trachomatis is the result of the unipolar growth and FtsZ-independent fission of this coccoid organism. This mechanism of cell division has not been documented in other human bacterial pathogens suggesting the potential for developing Chlamydia-specific therapeutic treatments. PMID:27505160

  12. Coronaviruses in polarized epithelial cells

    NARCIS (Netherlands)

    Rossen, J W; Bekker, C P; Voorhout, W F; Horzinek, M C; Van der Ende, A; Strous, G J; Rottier, P J

    1995-01-01

    Coronaviruses have a marked tropism for epithelial cells. In this paper the interactions of the porcine transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV-A59) with epithelial cells are compared. Porcine (LLC-PK1) and murine (mTAL) epithelial cells were grown on permeable supp

  13. Asymmetric protein localization in planar cell polarity

    Science.gov (United States)

    Peng, Ying; Axelrod, Jeffrey D.

    2016-01-01

    The polarization of epithelial cells along an axis orthogonal to their apical-basal axis is increasingly recognized for roles in a variety of developmental events and physiological functions. While now studied in many model organisms, mechanistic understanding is rooted in intensive investigations of Planar Cell Polarity (PCP) in Drosophila. Consensus has emerged that two molecular modules, referred to here as the global and core modules, operate upstream of effector proteins to produce morphological PCP. Proteins of the core module develop subcellular asymmetry, accumulating in two groups on opposite sides of cells, consistent with proposed functions in producing cell polarity and in communicating that polarity between neighboring cells. Less clear are the molecular and cell biological mechanisms underlying core module function in the generation and communication of subcellular asymmetry, and the relationship between the global and core modules. In this review, we discuss these two unresolved questions, highlighting important studies and potentially enlightening avenues for further investigation. It is likely that results from Drosophila will continue to inform our views of the growing list of examples of PCP in vertebrate systems. PMID:23140624

  14. Modeling the Control of Planar Cell Polarity

    Science.gov (United States)

    Axelrod, Jeffrey D.; Tomlin, Claire J.

    2016-01-01

    A growing list of medically important developmental defects and disease mechanisms can be traced to disruption of the Planar Cell Polarity (PCP) pathway. The PCP system polarizes cells in epithelial sheets along an axis orthogonal to their apical-basal axis. Studies in the fruitfly, Drosophila, have led to the concept of a modular system controlling PCP. The components of the PCP signaling modules, and the effector systems with which they interact, function together to produce emergent patterns. Experimental methods allow the manipulation of individual PCP signaling molecules in specified groups of cells; these interventions not only perturb the polarization of the targeted cells at a subcellular level, but also perturb patterns of polarity at the multicellular level, often affecting nearby cells in characteristic ways. These kinds of experiments should, in principle, allow one to infer the architecture within and between modules, but the relationships between molecular interactions and tissue-level pattern are sufficiently complex that they defy intuitive understanding. Mathematical modeling has been an important tool to address these problems. This review explores the emergence of a local signaling hypothesis, and describes how a local intercellular signal, coupled with a directional cue, can give rise to global pattern. We will discuss the critical role mathematical modeling has played in guiding and interpreting experimental results, and speculate about future roles for mathematical modeling of PCP. Mathematical models at varying levels of abstraction have and are expected to continue contributing in distinct ways to understanding the regulation of PCP signaling. PMID:21755606

  15. Reproducibility of polar map generation and assessment of defect severity and extent assessment in myocardial perfusion imaging using positron emission tomography

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the reliability of new software developed for the analysis of cardiac tomographic data. The algorithm delineates the long axis and defines the basal plane and subsequently generates polar maps to quantitatively and reproducibly assess the size and severity of perfusion defects. The developed technique requires an initial manual estimate of the left ventricular long axis and calculates the volumetric maximum myocardial activity distribution. This surface is used to map three-dimensional tracer accumulation onto a two-dimensional representation (polar map), which is the basis for further processing. The spatial information is used to compute geometrical and mechanical properties of a solid model of the left ventricle including the left heart chamber. A new estimate of the axis is determined from this model, and the previously outlined procedure is repeated together with an automated definition of the valve plane until differences between the polar maps can be neglected. This quantitative analysis software was validated in phantom studies with defects of known masses and in ten data sets from normals and patients with coronary artery disease of various severity. We investigated the reproducibility of the maps with the introduction of a similarity criterion where the ratio of two corresponding polar map elements lies within a 10% interval. The maps were also used to measure intra-and interobserver variability in respect of defect size and severity. In the phantom studies, it was possible to reliably assess mass information over a wide range of defects from 5 to 60 g (slope: 1.02, offset -0.68, r = 0.972). Patient studies revealed a statistically significant increase in the reproducibility of the automatic technique compared with the manual approach: 54%±19% (manual) compared with 88%±9% (automatic) for observer 1 and 61%±20% vs 82%±5% for observer 2, respectively. The intervariability analysis showed a significant

  16. Entry of genital Chlamydia trachomatis into polarized human epithelial cells.

    Science.gov (United States)

    Wyrick, P B; Choong, J; Davis, C H; Knight, S T; Royal, M O; Maslow, A S; Bagnell, C R

    1989-01-01

    To study the initial invasion process(es) of genital chlamydiae, a model system consisting of hormonally maintained primary cultures of human endometrial gland epithelial cells (HEGEC), grown in a polarized orientation on collagen-coated filters, was utilized. After Chlamydia trachomatis inoculation of the apical surface of polarized HEGEC, chlamydiae were readily visualized, by transmission electron microscopy, in coated pits and coated vesicles. This was true for HEGEC maintained in physiologic concentrations of estrogen (proliferative phase) and of estrogen plus progesterone (secretory phase), despite the finding that association of chlamydiae with secretory-phase HEGEC is significantly reduced (P = 0.025; A.S. Maslow, C.H. Davis, J. Choong, and P.B. Wyrick, Am. J. Obstet. Gynecol. 159:1006-1014, 1988). In contrast, chlamydiae were rarely observed in the clathrin-associated structures if the HEGEC were cultured on plastic surfaces. The same pattern of coated pit versus noncoated pit entry was reproducible in HeLa cells. The quantity of coated pits associated with isolated membrane sheets derived from HeLa cells, grown on poly-L-lysine-coated cover slips in medium containing the female hormones, was not significantly different as monitored by radiolabeling studies and by laser scanning microscopy. These data suggest that culture conditions which mimic in vivo cellular organization may enhance entry into coated pits for some obligate intracellular pathogens. Images PMID:2744852

  17. A stable and reproducible human blood-brain barrier model derived from hematopoietic stem cells.

    Directory of Open Access Journals (Sweden)

    Romeo Cecchelli

    Full Text Available The human blood brain barrier (BBB is a selective barrier formed by human brain endothelial cells (hBECs, which is important to ensure adequate neuronal function and protect the central nervous system (CNS from disease. The development of human in vitro BBB models is thus of utmost importance for drug discovery programs related to CNS diseases. Here, we describe a method to generate a human BBB model using cord blood-derived hematopoietic stem cells. The cells were initially differentiated into ECs followed by the induction of BBB properties by co-culture with pericytes. The brain-like endothelial cells (BLECs express tight junctions and transporters typically observed in brain endothelium and maintain expression of most in vivo BBB properties for at least 20 days. The model is very reproducible since it can be generated from stem cells isolated from different donors and in different laboratories, and could be used to predict CNS distribution of compounds in human. Finally, we provide evidence that Wnt/β-catenin signaling pathway mediates in part the BBB inductive properties of pericytes.

  18. A gas cell for stopping, storing and polarizing radioactive particles

    Science.gov (United States)

    Sytema, A.; van den Berg, J. E.; Böll, O.; Chernowitz, D.; Dijck, E. A.; Grasdijk, J. O.; Hoekstra, S.; Jungmann, K.; Mathavan, S. C.; Meinema, C.; Mohanty, A.; Müller, S. E.; Nuñez Portela, M.; Onderwater, C. J. G.; Pijpker, C.; Willmann, L.; Wilschut, H. W.

    2016-06-01

    A radioactive beam of 20Na is stopped in a gas cell filled with Ne gas. The stopped particles are polarized by optical pumping. The degree of polarization that can be achieved is studied. A maximum polarization of 50% was found. The dynamic processes in the cell are described with a phenomenological model.

  19. Subtyping of nonsmall cell lung cancer on cytology specimens: Reproducibility of cytopathologic diagnoses on sparse material

    DEFF Research Database (Denmark)

    Haukali, O. S.; Henrik, H.; Olsen, Karen Ege;

    2014-01-01

    , including metastases. Reproducibility was analyzed using Kappa statistics. Interobserver reproducibility of the diagnoses in round 1 was good to very good (kappa 0.57-0.71) and very good in round 2 (0.63-0.80). Reproducibility of subclassification of NSCLC based on MGG stained smear and IHC on CS, was very...

  20. Auxin regulation of cell polarity in plants.

    Science.gov (United States)

    Pan, Xue; Chen, Jisheng; Yang, Zhenbiao

    2015-12-01

    Auxin is well known to control pattern formation and directional growth at the organ/tissue levels via the nuclear TIR1/AFB receptor-mediated transcriptional responses. Recent studies have expanded the arena of auxin actions as a trigger or key regulator of cell polarization and morphogenesis. These actions require non-transcriptional responses such as changes in the cytoskeleton and vesicular trafficking, which are commonly regulated by ROP/Rac GTPase-dependent pathways. These findings beg for the question about the nature of auxin receptors that regulate these responses and renew the interest in ABP1 as a cell surface auxin receptor, including the work showing auxin-binding protein 1 (ABP1) interacts with the extracellular domain of the transmembrane kinase (TMK) receptor-like kinases in an auxin-dependent manner, as well as the debate on this auxin binding protein discovered about 40 years ago. This review highlights recent work on the non-transcriptional auxin signaling mechanisms underscoring cell polarity and shape formation in plants. PMID:26599954

  1. Mechanics and polarity in cell motility

    Science.gov (United States)

    Ambrosi, D.; Zanzottera, A.

    2016-09-01

    The motility of a fish keratocyte on a flat substrate exhibits two distinct regimes: the non-migrating and the migrating one. In both configurations the shape is fixed in time and, when the cell is moving, the velocity is constant in magnitude and direction. Transition from a stable configuration to the other one can be produced by a mechanical or chemotactic perturbation. In order to point out the mechanical nature of such a bistable behaviour, we focus on the actin dynamics inside the cell using a minimal mathematical model. While the protein diffusion, recruitment and segregation govern the polarization process, we show that the free actin mass balance, driven by diffusion, and the polymerized actin retrograde flow, regulated by the active stress, are sufficient ingredients to account for the motile bistability. The length and velocity of the cell are predicted on the basis of the parameters of the substrate and of the cell itself. The key physical ingredient of the theory is the exchange among actin phases at the edges of the cell, that plays a central role both in kinematics and in dynamics.

  2. Single-cell protein dynamics reproduce universal fluctuations in cell populations

    CERN Document Server

    Brenner, Naama; Rotella, James S; Salman, Hanna

    2015-01-01

    Protein fluctuations in cell populations have recently been shown to exhibit a universal distribution shape under a broad range of biological realizations. Here, measuring protein content in individual bacteria continuously over ~70 generations, we show that single-cell trajectories fluctuate around their average with the same distribution shape as the population, i.e. their relative fluctuations are ergodic. Analysis of these temporal trajectories reveals that one effective random variable, sampled once each cell cycle, suffices to reconstruct the distribution from the trajectory. This in turn implies that cellular microscopic processes are strongly buffered and population-level protein distributions are insensitive to details of the intracellular dynamics. Probing them thus requires searching for novel universality-breaking experimental perturbations.

  3. Sterol-Rich Membrane Domains Define Fission Yeast Cell Polarity.

    Science.gov (United States)

    Makushok, Tatyana; Alves, Paulo; Huisman, Stephen Michiel; Kijowski, Adam Rafal; Brunner, Damian

    2016-05-19

    Cell polarization is crucial for the functioning of all organisms. The cytoskeleton is central to the process but its role in symmetry breaking is poorly understood. We study cell polarization when fission yeast cells exit starvation. We show that the basis of polarity generation is de novo sterol biosynthesis, cell surface delivery of sterols, and their recruitment to the cell poles. This involves four phases occurring independent of the polarity factor cdc42p. Initially, multiple, randomly distributed sterol-rich membrane (SRM) domains form at the plasma membrane, independent of the cytoskeleton and cell growth. These domains provide platforms on which the growth and polarity machinery assembles. SRM domains are then polarized by the microtubule-dependent polarity factor tea1p, which prepares for monopolar growth initiation and later switching to bipolar growth. SRM polarization requires F-actin but not the F-actin organizing polarity factors for3p and bud6p. We conclude that SRMs are key to cell polarization. PMID:27180904

  4. Qualitative and quantitative histopathology in transitional cell carcinomas of the urinary bladder. An international investigation of intra- and interobserver reproducibility

    DEFF Research Database (Denmark)

    Sørensen, Flemming Brandt; Sasaki, M; Fukuzawa, S;

    1994-01-01

    BACKGROUND: Histopathologic, prognosis-related grading of malignancy by means of morphologic examination in transitional cell carcinomas of the urinary bladder (TCC) may be subject to observer variation, resulting in a reduced level of reproducibility. This may confound comparisons of treatment...

  5. Polarizing intestinal epithelial cells electrically through Ror2

    OpenAIRE

    Cao, L; McCaig, CD; Scott, RH; Zhao, S.; G. Milne; Clevers, H; Zhao, M; Pu, J

    2014-01-01

    ABSTRACT The apicobasal polarity of enterocytes determines where the brush border membrane (apical membrane) will form, but how this apical membrane faces the lumen is not well understood. The electrical signal across the epithelium could serve as a coordinating cue, orienting and polarizing enterocytes. Here, we show that applying a physiological electric field to intestinal epithelial cells, to mimic the natural electric field created by the transepithelial potential difference, polarized p...

  6. Dynamic Contrast-enhanced MR Imaging in Renal Cell Carcinoma: Reproducibility of Histogram Analysis on Pharmacokinetic Parameters

    Science.gov (United States)

    Wang, Hai-yi; Su, Zi-hua; Xu, Xiao; Sun, Zhi-peng; Duan, Fei-xue; Song, Yuan-yuan; Li, Lu; Wang, Ying-wei; Ma, Xin; Guo, Ai-tao; Ma, Lin; Ye, Hui-yi

    2016-01-01

    Pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been increasingly used to evaluate the permeability of tumor vessel. Histogram metrics are a recognized promising method of quantitative MR imaging that has been recently introduced in analysis of DCE-MRI pharmacokinetic parameters in oncology due to tumor heterogeneity. In this study, 21 patients with renal cell carcinoma (RCC) underwent paired DCE-MRI studies on a 3.0 T MR system. Extended Tofts model and population-based arterial input function were used to calculate kinetic parameters of RCC tumors. Mean value and histogram metrics (Mode, Skewness and Kurtosis) of each pharmacokinetic parameter were generated automatically using ImageJ software. Intra- and inter-observer reproducibility and scan–rescan reproducibility were evaluated using intra-class correlation coefficients (ICCs) and coefficient of variation (CoV). Our results demonstrated that the histogram method (Mode, Skewness and Kurtosis) was not superior to the conventional Mean value method in reproducibility evaluation on DCE-MRI pharmacokinetic parameters (K trans & Ve) in renal cell carcinoma, especially for Skewness and Kurtosis which showed lower intra-, inter-observer and scan-rescan reproducibility than Mean value. Our findings suggest that additional studies are necessary before wide incorporation of histogram metrics in quantitative analysis of DCE-MRI pharmacokinetic parameters. PMID:27380733

  7. A stepwise approach for the reproducible optimization of PAMO expression in Escherichia coli for whole-cell biocatalysis

    Directory of Open Access Journals (Sweden)

    van Bloois Edwin

    2012-06-01

    Full Text Available Abstract Background Baeyer-Villiger monooxygenases (BVMOs represent a group of enzymes of considerable biotechnological relevance as illustrated by their growing use as biocatalyst in a variety of synthetic applications. However, due to their increased use the reproducible expression of BVMOs and other biotechnologically relevant enzymes has become a pressing matter while knowledge about the factors governing their reproducible expression is scattered. Results Here, we have used phenylacetone monooxygenase (PAMO from Thermobifida fusca, a prototype Type I BVMO, as a model enzyme to develop a stepwise strategy to optimize the biotransformation performance of recombinant E. coli expressing PAMO in 96-well microtiter plates in a reproducible fashion. Using this system, the best expression conditions of PAMO were investigated first, including different host strains, temperature as well as time and induction period for PAMO expression. This optimized system was used next to improve biotransformation conditions, the PAMO-catalyzed conversion of phenylacetone, by evaluating the best electron donor, substrate concentration, and the temperature and length of biotransformation. Combining all optimized parameters resulted in a more than four-fold enhancement of the biocatalytic performance and, importantly, this was highly reproducible as indicated by the relative standard deviation of 1% for non-washed cells and 3% for washed cells. Furthermore, the optimized procedure was successfully adapted for activity-based mutant screening. Conclusions Our optimized procedure, which provides a comprehensive overview of the key factors influencing the reproducible expression and performance of a biocatalyst, is expected to form a rational basis for the optimization of miniaturized biotransformations and for the design of novel activity-based screening procedures suitable for BVMOs and other NAD(PH-dependent enzymes as well.

  8. Polarity in Stem Cell Division: Asymmetric Stem Cell Division in Tissue Homeostasis

    OpenAIRE

    Yamashita, Yukiko M; Yuan, Hebao; Cheng, Jun; Hunt, Alan J.

    2010-01-01

    Many adult stem cells divide asymmetrically to balance self-renewal and differentiation, thereby maintaining tissue homeostasis. Asymmetric stem cell divisions depend on asymmetric cell architecture (i.e., cell polarity) within the cell and/or the cellular environment. In particular, as residents of the tissues they sustain, stem cells are inevitably placed in the context of the tissue architecture. Indeed, many stem cells are polarized within their microenvironment, or the stem cell niche, a...

  9. Determining the interobserver reproducibility of Pap smears in the diagnosis of epithelial cell abnormalities

    Directory of Open Access Journals (Sweden)

    Izadi-Mood N

    2011-07-01

    Full Text Available "n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Cancer of uterine cervix is the second cause of death in women in the world and the most common cause in developing countries. Because the majority of women with invasive cervical cancer of the uterine have not previously undergone screening, many clinicians assume that Pap smear has a high degree of accuracy; but problems such as false positive and false negative interpretations, as well as interobserver variability have questioned its validity."n"nMethods : We retrieved 162 positive cervical smears that had been originally interpreted as ASC-US, ASC-H, LSIL, HSIL, SCC, AGC and adenocarcinoma from the cytology archives of Women's Hospital in Tehran, Iran. The slides were rescreened by an experienced pathologist and reclassified in the mentioned categories. All the 162 slides were reviewed by three more pathologists in a blind study using interpretative criteria utilized in their daily routine to evaluate interobserver reproducibility. To increase the level of interobserver agreement, the diagnostic categories were reduced to squamous Vs. glandular abnormalities and invasive (SCC and adenocarcinoma Vs. non-invasive abnormalities."n"nResults : The results obtained in this study indicated slight interobserver agreement (k=0.26. The most reproducible category was the invasive category (SCC in addition to adenocarcinoma and the least agreement was seen for HSIL (k=0.19. "n"nConclusion: This study showed that reproducibility of cytological interpretation of conventional Pap smears

  10. A Predictive Model for Yeast Cell Polarization in Pheromone Gradients

    Science.gov (United States)

    Calvez, Vincent; Voituriez, Raphaël; Gonçalves-Sá, Joana; Guo, Chin-Lin; Jiang, Xingyu; Murray, Andrew; Meunier, Nicolas

    2016-01-01

    Budding yeast cells exist in two mating types, a and α, which use peptide pheromones to communicate with each other during mating. Mating depends on the ability of cells to polarize up pheromone gradients, but cells also respond to spatially uniform fields of pheromone by polarizing along a single axis. We used quantitative measurements of the response of a cells to α-factor to produce a predictive model of yeast polarization towards a pheromone gradient. We found that cells make a sharp transition between budding cycles and mating induced polarization and that they detect pheromone gradients accurately only over a narrow range of pheromone concentrations corresponding to this transition. We fit all the parameters of the mathematical model by using quantitative data on spontaneous polarization in uniform pheromone concentration. Once these parameters have been computed, and without any further fit, our model quantitatively predicts the yeast cell response to pheromone gradient providing an important step toward understanding how cells communicate with each other. PMID:27077831

  11. A Predictive Model for Yeast Cell Polarization in Pheromone Gradients.

    Science.gov (United States)

    Muller, Nicolas; Piel, Matthieu; Calvez, Vincent; Voituriez, Raphaël; Gonçalves-Sá, Joana; Guo, Chin-Lin; Jiang, Xingyu; Murray, Andrew; Meunier, Nicolas

    2016-04-01

    Budding yeast cells exist in two mating types, a and α, which use peptide pheromones to communicate with each other during mating. Mating depends on the ability of cells to polarize up pheromone gradients, but cells also respond to spatially uniform fields of pheromone by polarizing along a single axis. We used quantitative measurements of the response of a cells to α-factor to produce a predictive model of yeast polarization towards a pheromone gradient. We found that cells make a sharp transition between budding cycles and mating induced polarization and that they detect pheromone gradients accurately only over a narrow range of pheromone concentrations corresponding to this transition. We fit all the parameters of the mathematical model by using quantitative data on spontaneous polarization in uniform pheromone concentration. Once these parameters have been computed, and without any further fit, our model quantitatively predicts the yeast cell response to pheromone gradient providing an important step toward understanding how cells communicate with each other. PMID:27077831

  12. Reproducibility of Illumina platform deep sequencing errors allows accurate determination of DNA barcodes in cells.

    NARCIS (Netherlands)

    Beltman, J.B.; Urbanus, J.; Velds, A.; Rooij, van N.; Rohr, J.C.; Naik, S.H.; Schumacher, T.N.

    2016-01-01

    BACKGROUND Next generation sequencing (NGS) of amplified DNA is a powerful tool to describe genetic heterogeneity within cell populations that can both be used to investigate the clonal structure of cell populations and to perform genetic lineage tracing. For applications in which both abundant and

  13. Prognostic Value and Reproducibility of Pretreatment CT Texture Features in Stage III Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fried, David V. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhou, Shouhao [Division of Quantitative Sciences, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mawlawi, Osama [Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas (United States); Ibbott, Geoffrey [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas (United States); Court, Laurence E., E-mail: LECourt@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas (United States)

    2014-11-15

    Purpose: To determine whether pretreatment CT texture features can improve patient risk stratification beyond conventional prognostic factors (CPFs) in stage III non-small cell lung cancer (NSCLC). Methods and Materials: We retrospectively reviewed 91 cases with stage III NSCLC treated with definitive chemoradiation therapy. All patients underwent pretreatment diagnostic contrast enhanced computed tomography (CE-CT) followed by 4-dimensional CT (4D-CT) for treatment simulation. We used the average-CT and expiratory (T50-CT) images from the 4D-CT along with the CE-CT for texture extraction. Histogram, gradient, co-occurrence, gray tone difference, and filtration-based techniques were used for texture feature extraction. Penalized Cox regression implementing cross-validation was used for covariate selection and modeling. Models incorporating texture features from the 33 image types and CPFs were compared to those with models incorporating CPFs alone for overall survival (OS), local-regional control (LRC), and freedom from distant metastases (FFDM). Predictive Kaplan-Meier curves were generated using leave-one-out cross-validation. Patients were stratified based on whether their predicted outcome was above or below the median. Reproducibility of texture features was evaluated using test-retest scans from independent patients and quantified using concordance correlation coefficients (CCC). We compared models incorporating the reproducibility seen on test-retest scans to our original models and determined the classification reproducibility. Results: Models incorporating both texture features and CPFs demonstrated a significant improvement in risk stratification compared to models using CPFs alone for OS (P=.046), LRC (P=.01), and FFDM (P=.005). The average CCCs were 0.89, 0.91, and 0.67 for texture features extracted from the average-CT, T50-CT, and CE-CT, respectively. Incorporating reproducibility within our models yielded 80.4% (±3.7% SD), 78.3% (±4.0% SD), and 78

  14. Prognostic Value and Reproducibility of Pretreatment CT Texture Features in Stage III Non-Small Cell Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: To determine whether pretreatment CT texture features can improve patient risk stratification beyond conventional prognostic factors (CPFs) in stage III non-small cell lung cancer (NSCLC). Methods and Materials: We retrospectively reviewed 91 cases with stage III NSCLC treated with definitive chemoradiation therapy. All patients underwent pretreatment diagnostic contrast enhanced computed tomography (CE-CT) followed by 4-dimensional CT (4D-CT) for treatment simulation. We used the average-CT and expiratory (T50-CT) images from the 4D-CT along with the CE-CT for texture extraction. Histogram, gradient, co-occurrence, gray tone difference, and filtration-based techniques were used for texture feature extraction. Penalized Cox regression implementing cross-validation was used for covariate selection and modeling. Models incorporating texture features from the 33 image types and CPFs were compared to those with models incorporating CPFs alone for overall survival (OS), local-regional control (LRC), and freedom from distant metastases (FFDM). Predictive Kaplan-Meier curves were generated using leave-one-out cross-validation. Patients were stratified based on whether their predicted outcome was above or below the median. Reproducibility of texture features was evaluated using test-retest scans from independent patients and quantified using concordance correlation coefficients (CCC). We compared models incorporating the reproducibility seen on test-retest scans to our original models and determined the classification reproducibility. Results: Models incorporating both texture features and CPFs demonstrated a significant improvement in risk stratification compared to models using CPFs alone for OS (P=.046), LRC (P=.01), and FFDM (P=.005). The average CCCs were 0.89, 0.91, and 0.67 for texture features extracted from the average-CT, T50-CT, and CE-CT, respectively. Incorporating reproducibility within our models yielded 80.4% (±3.7% SD), 78.3% (±4.0% SD), and 78

  15. Entry of genital Chlamydia trachomatis into polarized human epithelial cells.

    OpenAIRE

    Wyrick, P B; Choong, J; Davis, C H; Knight, S T; Royal, M O; Maslow, A S; Bagnell, C R

    1989-01-01

    To study the initial invasion process(es) of genital chlamydiae, a model system consisting of hormonally maintained primary cultures of human endometrial gland epithelial cells (HEGEC), grown in a polarized orientation on collagen-coated filters, was utilized. After Chlamydia trachomatis inoculation of the apical surface of polarized HEGEC, chlamydiae were readily visualized, by transmission electron microscopy, in coated pits and coated vesicles. This was true for HEGEC maintained in physiol...

  16. Reproducibility of Illumina platform deep sequencing errors allows accurate determination of DNA barcodes in cells.

    OpenAIRE

    Beltman, J.B.; J. Urbanus; Velds, A.; de, Rooij, R.; Rohr, J.C.; S.H. Naik; T.N. Schumacher.

    2016-01-01

    BACKGROUND Next generation sequencing (NGS) of amplified DNA is a powerful tool to describe genetic heterogeneity within cell populations that can both be used to investigate the clonal structure of cell populations and to perform genetic lineage tracing. For applications in which both abundant and rare sequences are biologically relevant, the relatively high error rate of NGS techniques complicates data analysis, as it is difficult to distinguish rare true sequences from spurious sequences t...

  17. Apicobasal Polarity Controls Lymphocyte Adhesion to Hepatic Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Natalia Reglero-Real

    2014-09-01

    Full Text Available Loss of apicobasal polarity is a hallmark of epithelial pathologies. Leukocyte infiltration and crosstalk with dysfunctional epithelial barriers are crucial for the inflammatory response. Here, we show that apicobasal architecture regulates the adhesion between hepatic epithelial cells and lymphocytes. Polarized hepatocytes and epithelium from bile ducts segregate the intercellular adhesion molecule 1 (ICAM-1 adhesion receptor onto their apical, microvilli-rich membranes, which are less accessible by circulating immune cells. Upon cell depolarization, hepatic ICAM-1 becomes exposed and increases lymphocyte binding. Polarized hepatic cells prevent ICAM-1 exposure to lymphocytes by redirecting basolateral ICAM-1 to apical domains. Loss of ICAM-1 polarity occurs in human inflammatory liver diseases and can be induced by the inflammatory cytokine tumor necrosis factor alpha (TNF-α. We propose that adhesion receptor polarization is a parenchymal immune checkpoint that allows functional epithelium to hamper leukocyte binding. This contributes to the haptotactic guidance of leukocytes toward neighboring damaged or chronically inflamed epithelial cells that expose their adhesion machinery.

  18. Continuous Flow Polymer Synthesis toward Reproducible Large-Scale Production for Efficient Bulk Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Pirotte, Geert; Kesters, Jurgen; Verstappen, Pieter; Govaerts, Sanne; Manca, Jean; Lutsen, Laurence; Vanderzande, Dirk; Maes, Wouter

    2015-10-12

    Organic photovoltaics (OPV) have attracted great interest as a solar cell technology with appealing mechanical, aesthetical, and economies-of-scale features. To drive OPV toward economic viability, low-cost, large-scale module production has to be realized in combination with increased top-quality material availability and minimal batch-to-batch variation. To this extent, continuous flow chemistry can serve as a powerful tool. In this contribution, a flow protocol is optimized for the high performance benzodithiophene-thienopyrroledione copolymer PBDTTPD and the material quality is probed through systematic solar-cell evaluation. A stepwise approach is adopted to turn the batch process into a reproducible and scalable continuous flow procedure. Solar cell devices fabricated using the obtained polymer batches deliver an average power conversion efficiency of 7.2 %. Upon incorporation of an ionic polythiophene-based cathodic interlayer, the photovoltaic performance could be enhanced to a maximum efficiency of 9.1 %. PMID:26388210

  19. Electric pulse stimulation of cultured murine muscle cells reproduces gene expression changes of trained mouse muscle.

    Directory of Open Access Journals (Sweden)

    Nathalie Burch

    Full Text Available Adequate levels of physical activity are at the center of a healthy lifestyle. However, the molecular mechanisms that mediate the beneficial effects of exercise remain enigmatic. This gap in knowledge is caused by the lack of an amenable experimental model system. Therefore, we optimized electric pulse stimulation of muscle cells to closely recapitulate the plastic changes in gene expression observed in a trained skeletal muscle. The exact experimental conditions were established using the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha as a marker for an endurance-trained muscle fiber. We subsequently compared the changes in the relative expression of metabolic and myofibrillar genes in the muscle cell system with those observed in mouse muscle in vivo following either an acute or repeated bouts of treadmill exercise. Importantly, in electrically stimulated C2C12 mouse muscle cells, the qualitative transcriptional adaptations were almost identical to those in trained muscle, but differ from the acute effects of exercise on muscle gene expression. In addition, significant alterations in the expression of myofibrillar proteins indicate that this stimulation could be used to modulate the fiber-type of muscle cells in culture. Our data thus describe an experimental cell culture model for the study of at least some of the transcriptional aspects of skeletal muscle adaptation to physical activity. This system will be useful for the study of the molecular mechanisms that regulate exercise adaptation in muscle.

  20. A computational model incorporating neural stem cell dynamics reproduces glioma incidence across the lifespan in the human population.

    Directory of Open Access Journals (Sweden)

    Roman Bauer

    Full Text Available Glioma is the most common form of primary brain tumor. Demographically, the risk of occurrence increases until old age. Here we present a novel computational model to reproduce the probability of glioma incidence across the lifespan. Previous mathematical models explaining glioma incidence are framed in a rather abstract way, and do not directly relate to empirical findings. To decrease this gap between theory and experimental observations, we incorporate recent data on cellular and molecular factors underlying gliomagenesis. Since evidence implicates the adult neural stem cell as the likely cell-of-origin of glioma, we have incorporated empirically-determined estimates of neural stem cell number, cell division rate, mutation rate and oncogenic potential into our model. We demonstrate that our model yields results which match actual demographic data in the human population. In particular, this model accounts for the observed peak incidence of glioma at approximately 80 years of age, without the need to assert differential susceptibility throughout the population. Overall, our model supports the hypothesis that glioma is caused by randomly-occurring oncogenic mutations within the neural stem cell population. Based on this model, we assess the influence of the (experimentally indicated decrease in the number of neural stem cells and increase of cell division rate during aging. Our model provides multiple testable predictions, and suggests that different temporal sequences of oncogenic mutations can lead to tumorigenesis. Finally, we conclude that four or five oncogenic mutations are sufficient for the formation of glioma.

  1. Polarized entry of canine parvovirus in an epithelial cell line.

    OpenAIRE

    Basak, S; Compans, R W

    1989-01-01

    The binding and uptake of canine parvovirus (CPV) in polarized epithelial cells were investigated by growing the cells on a permeable support and inoculating with the virus either from the apical or basolateral surface. Binding of radiolabeled CPV occurred preferentially on the basolateral surface. In contrast, when a similar experiment was carried out on nonpolarized A72 cells, virus binding occurred regardless of the direction of virus input. Binding appeared to be specific for CPV and coul...

  2. Improvement of Charge Collection and Performance Reproducibility in Inverted Organic Solar Cells by Suppression of ZnO Subgap States.

    Science.gov (United States)

    Wu, Bo; Wu, Zhenghui; Yang, Qingyi; Zhu, Furong; Ng, Tsz-Wai; Lee, Chun-Sing; Cheung, Sin-Hang; So, Shu-Kong

    2016-06-15

    Organic solar cells (OSCs) with inverted structure usually exhibit higher power conversion efficiency (PCE) and are more stable than corresponding devices with regular configuration. Indium tin oxide (ITO) surface is often modified with solution-processed low work function metal oxides, such as ZnO, serving as the transparent cathode. However, the defect-induced subgap states in the ZnO interlayer hamper the efficient charge collection and the performance reproducibility of the OSCs. In this work, we demonstrate that suppression of the ZnO subgap states by modification of its surface with an ultrathin Al layer significantly improves the charge extraction and performance reproducibility, achieving PCE of 8.0%, which is ∼15% higher than that of a structurally identical control cell made with a pristine ZnO interlayer. Light intensity-dependent current density-voltage characteristic, photothermal deflection spectroscopy, and X-ray photoelectron spectroscopy measurements point out the enhancement of charge collection efficiency at the organic/cathode interface, due to the suppression of the subgap states in the ZnO interlayer. PMID:27224960

  3. Lipid polarity and sorting in epithelial cells

    OpenAIRE

    van Meer, G.; Simons, K.

    1988-01-01

    Apical and basolateral membrane domains of epithelial cell plasma membranes possess unique lipid compositions. The tight junction, the structure separating the two domains, forms a diffusion barrier for membrane components and thereby prevents intermixing of the two sets of lipids. The barrier apparently resides in the outer, exoplasmic leaflet of the plasma membrane bilayer. First data are now available on the generation of these differences in Madin-Darby canine kidney (MDCK) cells, grown o...

  4. Effects of Thermochemical Treatment on CuSbS2 Photovoltaic Absorber Quality and Solar Cell Reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    de Souza Lucas, Francisco Willian; Welch, Adam W.; Baranowski, Lauryn L.; Dippo, Patricia C.; Hempel, Hannes; Unold, Thomas; Eichberger, Rainer; Blank, Beatrix; Rau, Uwe; Mascaro, Lucia H.; Zakutayev, Andriy

    2016-08-25

    CuSbS2 is a promising nontoxic and earth-abundant photovoltaic absorber that is chemically simpler than the widely studied Cu2ZnSnS4. However, CuSbS2 photovoltaic (PV) devices currently have relatively low efficiency and poor reproducibility, often due to suboptimal material quality and insufficient optoelectronic properties. To address these issues, here we develop a thermochemical treatment (TT) for CuSbS2 thin films, which consists of annealing in Sb2S3 vapor followed by a selective KOH surface chemical etch. The annealed CuSbS2 films show improved structural quality and optoelectronic properties, such as stronger band-edge photoluminescence and longer photoexcited carrier lifetime. These improvements also lead to more reproducible CuSbS2 PV devices, with performance currently limited by a large cliff-type interface band offset with CdS contact. Overall, these results point to the potential avenues to further increase the performance of CuSbS2 thin film solar cell, and the findings can be transferred to other thin film photovoltaic technologies.

  5. Can radiomics features be reproducibly measured from CBCT images for patients with non-small cell lung cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Fave, Xenia, E-mail: xjfave@mdanderson.org; Fried, David [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Mackin, Dennis; Yang, Jinzhong; Zhang, Joy; Balter, Peter; Followill, David [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Gomez, Daniel [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Kyle Jones, A. [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Stingo, Francesco [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Fontenot, Jonas [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States); Court, Laurence [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

    2015-12-15

    Purpose: Increasing evidence suggests radiomics features extracted from computed tomography (CT) images may be useful in prognostic models for patients with nonsmall cell lung cancer (NSCLC). This study was designed to determine whether such features can be reproducibly obtained from cone-beam CT (CBCT) images taken using medical Linac onboard-imaging systems in order to track them through treatment. Methods: Test-retest CBCT images of ten patients previously enrolled in a clinical trial were retrospectively obtained and used to determine the concordance correlation coefficient (CCC) for 68 different texture features. The volume dependence of each feature was also measured using the Spearman rank correlation coefficient. Features with a high reproducibility (CCC > 0.9) that were not due to volume dependence in the patient test-retest set were further examined for their sensitivity to differences in imaging protocol, level of scatter, and amount of motion by using two phantoms. The first phantom was a texture phantom composed of rectangular cartridges to represent different textures. Features were measured from two cartridges, shredded rubber and dense cork, in this study. The texture phantom was scanned with 19 different CBCT imagers to establish the features’ interscanner variability. The effect of scatter on these features was studied by surrounding the same texture phantom with scattering material (rice and solid water). The effect of respiratory motion on these features was studied using a dynamic-motion thoracic phantom and a specially designed tumor texture insert of the shredded rubber material. The differences between scans acquired with different Linacs and protocols, varying amounts of scatter, and with different levels of motion were compared to the mean intrapatient difference from the test-retest image set. Results: Of the original 68 features, 37 had a CCC >0.9 that was not due to volume dependence. When the Linac manufacturer and imaging protocol

  6. Can radiomics features be reproducibly measured from CBCT images for patients with non-small cell lung cancer?

    International Nuclear Information System (INIS)

    Purpose: Increasing evidence suggests radiomics features extracted from computed tomography (CT) images may be useful in prognostic models for patients with nonsmall cell lung cancer (NSCLC). This study was designed to determine whether such features can be reproducibly obtained from cone-beam CT (CBCT) images taken using medical Linac onboard-imaging systems in order to track them through treatment. Methods: Test-retest CBCT images of ten patients previously enrolled in a clinical trial were retrospectively obtained and used to determine the concordance correlation coefficient (CCC) for 68 different texture features. The volume dependence of each feature was also measured using the Spearman rank correlation coefficient. Features with a high reproducibility (CCC > 0.9) that were not due to volume dependence in the patient test-retest set were further examined for their sensitivity to differences in imaging protocol, level of scatter, and amount of motion by using two phantoms. The first phantom was a texture phantom composed of rectangular cartridges to represent different textures. Features were measured from two cartridges, shredded rubber and dense cork, in this study. The texture phantom was scanned with 19 different CBCT imagers to establish the features’ interscanner variability. The effect of scatter on these features was studied by surrounding the same texture phantom with scattering material (rice and solid water). The effect of respiratory motion on these features was studied using a dynamic-motion thoracic phantom and a specially designed tumor texture insert of the shredded rubber material. The differences between scans acquired with different Linacs and protocols, varying amounts of scatter, and with different levels of motion were compared to the mean intrapatient difference from the test-retest image set. Results: Of the original 68 features, 37 had a CCC >0.9 that was not due to volume dependence. When the Linac manufacturer and imaging protocol

  7. The Signaling Mechanisms Underlying Cell Polarity and Chemotaxis

    OpenAIRE

    Wang, Fei

    2009-01-01

    Chemotaxis—the directed movement of cells in a gradient of chemoattractant—is essential for neutrophils to crawl to sites of inflammation and infection and for Dictyostelium discoideum (D. discoideum) to aggregate during morphogenesis. Chemoattractant-induced activation of spatially localized cellular signals causes cells to polarize and move toward the highest concentration of the chemoattractant. Extensive studies have been devoted to achieving a better understanding of the mechanism(s) use...

  8. Vectorial secretion of proteoglycans by polarized rat uterine epithelial cells

    OpenAIRE

    1988-01-01

    We have studied proteoglycan secretion using a recently developed system for the preparing of polarized primary cultures of rat uterine epithelial cells. To mimic their native environment better and provide a system for discriminating apical from basolateral compartments, we cultured cells on semipermeable supports impregnated with biomatrix. Keratan sulfate proteoglycans (KSPG) as well as heparan sulfate- containing molecules (HS[PG]) were the major sulfated products synthesized and secreted...

  9. Dressed Spin of Polarized 3He in a Cell

    CERN Document Server

    Chu, P H; Peng, J C; Beck, D H; Chandler, D E; Clayton, S; Hu, B Z; Ngan, S Y; Sham, C H; So, L H; Williamson, S; Yoder, J

    2010-01-01

    We report a measurement of the modification of the effective precession frequency of polarized 3He atoms in response to a dressing field in a room temperature cell. The 3He atoms were polarized using the metastability spin-exchange method. An oscillating dressing field is then applied perpendicular to the constant magnetic field. Modification of the 3He effective precession frequency was observed over a broad range of the amplitude and frequency of the dressing field. The observed effects are compared with calculations based on quantum optics formalism.

  10. Lis1 mediates planar polarity of auditory hair cells through regulation of microtubule organization

    OpenAIRE

    Sipe, Conor W.; Liu, Lixia; Lee, Jianyi; Grimsley-Myers, Cynthia; Lu, Xiaowei

    2013-01-01

    The V-shaped hair bundles atop auditory hair cells and their uniform orientation are manifestations of epithelial planar cell polarity (PCP) required for proper perception of sound. PCP is regulated at the tissue level by a conserved core Wnt/PCP pathway. However, the hair cell-intrinsic polarity machinery is poorly understood. Recent findings implicate hair cell microtubules in planar polarization of hair cells. To elucidate the microtubule-mediated polarity pathway, we analyzed Lis1 functio...

  11. Satellite Cells in Muscular Dystrophy - Lost in Polarity.

    Science.gov (United States)

    Chang, Natasha C; Chevalier, Fabien P; Rudnicki, Michael A

    2016-06-01

    Recent findings employing the mdx mouse model for Duchenne muscular dystrophy (DMD) have revealed that muscle satellite stem cells play a direct role in contributing to disease etiology and progression of DMD, the most common and severe form of muscular dystrophy. Lack of dystrophin expression in DMD has critical consequences in satellite cells including an inability to establish cell polarity, abrogation of asymmetric satellite stem-cell divisions, and failure to enter the myogenic program. Thus, muscle wasting in dystrophic mice is not only caused by myofiber fragility but is exacerbated by intrinsic satellite cell dysfunction leading to impaired regeneration. Despite intense research and clinical efforts, there is still no effective cure for DMD. In this review we highlight recent research advances in DMD and discuss the current state of treatment and, importantly, how we can incorporate satellite cell-targeted therapeutic strategies to correct satellite cell dysfunction in DMD. PMID:27161598

  12. [Polar coordinates representation based leukocyte segmentation of microscopic cell images].

    Science.gov (United States)

    Gu, Guanghua; Cui, Dong; Hao, Lianwang

    2010-12-01

    We propose an algorithm for segmentation of the overlapped leukocyte in the microscopic cell image. The histogram of the saturation channel in the cell image is smoothed to obtain the meaningful global valley point by the fingerprint smoothing method, and then the nucleus can be segmented. A circular region, containing the entire regions of the leukocyte, is marked off according to the equivalent sectional radius of the nucleus. Then, the edge of the overlapped leukocyte is represented by polar coordinates. The overlapped region by the change of the polar angle of the edge pixels is determined, and the closed edge of the leukocyte integrating the gradient information of the overlapped region is reconstructed. Finally, the leukocyte is exactly extracted. The experimental results show that our method has good performance in terms of recall ratio, precision ratio and pixel error ratio. PMID:21374971

  13. Centrosome polarization in T cells: a task for formins

    Directory of Open Access Journals (Sweden)

    Laura eAndrés-Delgado

    2013-07-01

    Full Text Available T-cell antigen receptor (TCR engagement triggers the rapid reorientation of the centrosome, which is associated with the secretory machinery, towards the immunological synapse (IS for polarized protein trafficking. Recent evidence indicates that upon TCR triggering the INF2 formin, together with the formins DIA1 and FMNL1, promotes the formation of a specialized array of stable detyrosinated MTs that breaks the symmetrical organization of the T-cell microtubule (MT cytoskeleton. The detyrosinated MT array and TCR-induced tyrosine phosphorylation should coincide for centrosome polarization. We propose that the pushing forces produced by the detyrosinated MT array, which modify the position of the centrosome, in concert with Src kinase dependent TCR signaling, which provide the reference frame with respect to which the centrosome reorients, result in the repositioning of the centrosome to the IS.

  14. Polarization and reprogramming of myeloid-derived suppressor cells

    OpenAIRE

    Yang, Wen-Chin; Ma, Ge; Chen, Shu-hsia; Pan, Ping-Ying

    2013-01-01

    Myeloid-derived suppressor cells (MDSC) have recently emerged as one of the central regulators of the immune system. In recent years, interest in understanding MDSC biology and applying MDSC for therapeutic purpose has exploded exponentially. Despite recent progress in MDSC biology, the mechanisms underlying MDSC development from expansion and activation to polarization in different diseases remain poorly understood. More recent studies have demonstrated that two MDSC subsets, M (monocytic)-M...

  15. Appearance of differentiated cells derived from polar body nuclei in the silkworm, Bombyx mori

    Directory of Open Access Journals (Sweden)

    Hiroki eSakai

    2013-09-01

    Full Text Available AbstractIn Bombyx mori, polar body nuclei are observed until 9h after egg lying, however, the fate of polar body nuclei remains unclear. To examine the fate of polar body nuclei, we employed a mutation of serosal cell pigmentation, pink-eyed white egg (pe. The heterozygous pe/+pe females produced black serosal cells in white eggs, while pe/pe females did not produce black serosal cells in white eggs. These results suggest that the appearance of black serosal cells in white eggs depends on the genotype (pe/ +pe of the mother. Because the polar body nuclei had +pe genes in the white eggs laid by a pe/ +pe female, polar body nuclei participate in development and differentiate into functional cell (serosal cells. Analyses of serosal cells pigmentation indicated that approximately 30% of the eggs contained polar-body-nucleus-derived cells. These results demonstrate that polar-body-nucleus-derived cells appeared at a high frequency under natural conditions. Approximately 80% of polar-body-nucleus-derived cells appeared near the anterior pole and the dorsal side, which is opposite to where embryogenesis occurs. The number of cells derived from the polar body nuclei was very low. Approximately 26 % of these eggs contained only one black serosal cell. PCR-based analysis revealed that the polar-body-nucleus-derived cells disappeared in late embryonic stages (stage 25. Overall, polar-body-nuclei-derived cells were unlikely to contribute to embryos.

  16. Periplasmic Acid Stress Increases Cell Division Asymmetry (Polar Aging of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Michelle W Clark

    Full Text Available Under certain kinds of cytoplasmic stress, Escherichia coli selectively reproduce by distributing the newer cytoplasmic components to new-pole cells while sequestering older, damaged components in cells inheriting the old pole. This phenomenon is termed polar aging or cell division asymmetry. It is unknown whether cell division asymmetry can arise from a periplasmic stress, such as the stress of extracellular acid, which is mediated by the periplasm. We tested the effect of periplasmic acid stress on growth and division of adherent single cells. We tracked individual cell lineages over five or more generations, using fluorescence microscopy with ratiometric pHluorin to measure cytoplasmic pH. Adherent colonies were perfused continually with LBK medium buffered at pH 6.00 or at pH 7.50; the external pH determines periplasmic pH. In each experiment, cell lineages were mapped to correlate division time, pole age and cell generation number. In colonies perfused at pH 6.0, the cells inheriting the oldest pole divided significantly more slowly than the cells inheriting the newest pole. In colonies perfused at pH 7.50 (near or above cytoplasmic pH, no significant cell division asymmetry was observed. Under both conditions (periplasmic pH 6.0 or pH 7.5 the cells maintained cytoplasmic pH values at 7.2-7.3. No evidence of cytoplasmic protein aggregation was seen. Thus, periplasmic acid stress leads to cell division asymmetry with minimal cytoplasmic stress.

  17. Interlaboratory reproducibility of semiautomated cell cycle analysis of flow cytometry DNA-histograms obtained from fresh material of 1,295 breast cancer cases.

    Science.gov (United States)

    Bergers, E; Montironi, R; van Diest, P J; Prete, E; Baak, J P

    1996-06-01

    Conflicting prognostic results have been published as to the DNA variables, such as DNA ploidy, DNA index, and % S-phase cells for breast cancer patients. These variables can be obtained by interpreting DNA histograms by cell cycle analysis. Explanations for these conflicting results might be found on the level of the interpretation of the DNA histograms. In a previous study, the semi automated cell cycle analysis computer program MultiCycle (Phoenix Flow Systems, San Diego, CA) showed high intralaboratory reproducibility. However, what types of DNA histograms may cause disagreements was still unclear. The aim of this study was to determine the interlaboratory reproducibility of MultiCycle-based cell cycle analysis of 1,295 flow cytometric DNA histograms derived from fresh frozen breast cancer material and to clarify potential sources of interobserver variation when analyzing DNA histograms. DNA ploidy classification into diploid, hyperdiploid, tetraploid, hypertetraploid, and multiploid showed an interlaboratory agreement of 94% (kappa value = 0.92). The 6% discrepancies (n = 74) were caused by tetraploid peaks, as established in one laboratory, which shifted outside the tetraploid region on reanalysis by the other laboratory (37%), shoulders sometimes interpreted as peaks (24%), small peaks not always recognized as such (24%), fitting failures (10%), and overlooking of tetraploid peaks (5%). Furthermore, the cell cycle analysis variables showed variable reproducibility. The % S-phase cells of the first, second, and third cell cycle showed overall a moderate reproducibility (0.62 R more reproducible with correlation coefficients of 0.89 and 0.81, respectively. The coefficient of variation of the G0/G1 peak of the first cell cycle, the DNA indices and the % diploid cells were highly reproducible (R > or = 0.94), and the % G2/M-phase cells of the first, second, and third cell cycle were poorly reproducible (0.22 R 0.68). When a cut-point was used at the mean value

  18. Planar Cell Polarity Controls Pancreatic Beta Cell Differentiation and Glucose Homeostasis

    DEFF Research Database (Denmark)

    Cortijo, Cedric; Gouzi, Mathieu; Tissir, Fadel;

    2012-01-01

    .5 synchronously to apicobasal polarization of pancreas progenitors. Loss of function of the two PCP core components Celsr2 and Celsr3 shows that they control the differentiation of endocrine cells from polarized progenitors, with a prevalent effect on insulin-producing beta cells. This results in a decreased...... glucose clearance. Loss of Celsr2 and 3 leads to a reduction of Jun phosphorylation in progenitors, which, in turn, reduces beta cell differentiation from endocrine progenitors. These results highlight the importance of the PCP pathway in cell differentiation in vertebrates. In addition, they reveal that...

  19. Challenge for lowering concentration polarization in solid oxide fuel cells

    Science.gov (United States)

    Shimada, Hiroyuki; Suzuki, Toshio; Yamaguchi, Toshiaki; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    In the scope of electrochemical phenomena, concentration polarization at electrodes is theoretically inevitable, and lowering the concentration overpotential to improve the performance of electrochemical cells has been a continuing challenge. Electrodes with highly controlled microstructure, i.e., high porosity and uniform large pores are therefore essential to achieve high performance electrochemical cells. In this study, state-of-the-art technology for controlling the microstructure of electrodes has been developed for realizing high performance support electrodes of solid oxide fuel cells (SOFCs). The key is controlling the porosity and pore size distribution to improve gas diffusion, while maintaining the integrity of the electrolyte and the structural strength of actual sized electrode supports needed for the target application. Planar anode-supported SOFCs developed in this study realize 5 μm thick dense electrolyte (yttria-stabilized zirconia: YSZ) and the anode substrate (Ni-YSZ) of 53.6 vol.% porosity with a large median pore diameter of 0.911 μm. Electrochemical measurements reveal that the performance of the anode-supported SOFCs improves with increasing anode porosity. This Ni-YSZ anode minimizes the concentration polarization, resulting in a maximum power density of 3.09 W cm-2 at 800 °C using humidified hydrogen fuel without any electrode functional layers.

  20. Airway epithelial homeostasis and planar cell polarity signaling depend on multiciliated cell differentiation

    Science.gov (United States)

    Vladar, Eszter K.; Nayak, Jayakar V.; Milla, Carlos E.; Axelrod, Jeffrey D.

    2016-01-01

    Motile airway cilia that propel contaminants out of the lung are oriented in a common direction by planar cell polarity (PCP) signaling, which localizes PCP protein complexes to opposite cell sides throughout the epithelium to orient cytoskeletal remodeling. In airway epithelia, PCP is determined in a 2-phase process. First, cell-cell communication via PCP complexes polarizes all cells with respect to the proximal-distal tissue axis. Second, during ciliogenesis, multiciliated cells (MCCs) undergo cytoskeletal remodeling to orient their cilia in the proximal direction. The second phase not only directs cilium polarization, but also consolidates polarization across the epithelium. Here, we demonstrate that in airway epithelia, PCP depends on MCC differentiation. PCP mutant epithelia have misaligned cilia, and also display defective barrier function and regeneration, indicating that PCP regulates multiple aspects of airway epithelial homeostasis. In humans, MCCs are often sparse in chronic inflammatory diseases, and these airways exhibit PCP dysfunction. The presence of insufficient MCCs impairs mucociliary clearance in part by disrupting PCP-driven polarization of the epithelium. Consistent with defective PCP, barrier function and regeneration are also disrupted. Pharmacological stimulation of MCC differentiation restores PCP and reverses these defects, suggesting its potential for broad therapeutic benefit in chronic inflammatory disease.

  1. Reproducibility of (18)F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR

    DEFF Research Database (Denmark)

    Rasmussen, J H; Fischer, B M; Aznar, M C;

    2015-01-01

    OBJECTIVE: To investigate reproducibility of fluorine-18 fludeoxyglucose ((18)F-FDG) uptake on (18)F-FDG positron emission tomography (PET)/CT and (18)F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: 30 patients with HNSCC were included in this prospecti...

  2. Reproducibility of 18F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR

    Science.gov (United States)

    Fischer, B M; Aznar, M C; Hansen, A E; Vogelius, I R; Löfgren, J; Andersen, F L; Loft, A; Kjaer, A; Højgaard, L; Specht, L

    2015-01-01

    Objective: To investigate reproducibility of fluorine-18 fludeoxyglucose (18F-FDG) uptake on 18F-FDG positron emission tomography (PET)/CT and 18F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). Methods: 30 patients with HNSCC were included in this prospective study. The patients were scanned twice before radiotherapy treatment with both PET/CT and PET/MR. Patients were scanned on the same scanners, 3 days apart and according to the same protocol. Metabolic tumour activity was measured by the maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively), and total lesion glycolysis from the metabolic tumour volume defined from ≥50% SUVmax. Bland–Altman analysis with limits of agreement, coefficient of variation (CV) from the two modalities were performed in order to test the reproducibility. Furthermore, CVs from SUVmax and SUVpeak were compared. The area under the curve from cumulative SUV–volume histograms were measured and tested for reproducibility of the distribution of 18F-FDG uptake. Results: 24 patients had two pre-treatment PET/CT scans and 21 patients had two pre-treatment PET/MR scans available for further analyses. Mean difference for SUVmax, peak and mean was approximately 4% for PET/CT and 3% for PET/MR, with 95% limits of agreement less than ±20%. CV was small (5–7%) for both modalities. There was no significant difference in CVs between PET/CT and PET/MR (p = 0.31). SUVmax was not more reproducible than SUVpeak (p = 0.09). Conclusion: 18F-FDG uptake in PET/CT and PET/MR is highly reproducible and we found no difference in reproducibility between PET/CT and PET/MR. Advances in knowledge: This is the first report to test reproducibility of PET/CT and PET/MR. PMID:25634069

  3. Muscle Stem Cell Fate Is Controlled by the Cell-Polarity Protein Scrib

    Directory of Open Access Journals (Sweden)

    Yusuke Ono

    2015-02-01

    Full Text Available Satellite cells are resident skeletal muscle stem cells that supply myonuclei for homeostasis, hypertrophy, and repair in adult muscle. Scrib is one of the major cell-polarity proteins, acting as a potent tumor suppressor in epithelial cells. Here, we show that Scrib also controls satellite-cell-fate decisions in adult mice. Scrib is undetectable in quiescent cells but becomes expressed during activation. Scrib is asymmetrically distributed in dividing daughter cells, with robust accumulation in cells committed to myogenic differentiation. Low Scrib expression is associated with the proliferative state and preventing self-renewal, whereas high Scrib levels reduce satellite cell proliferation. Satellite-cell-specific knockout of Scrib in mice causes a drastic and insurmountable defect in muscle regeneration. Thus, Scrib is a regulator of tissue stem cells, controlling population expansion and self-renewal with Scrib expression dynamics directing satellite cell fate.

  4. Epithelial cell polarity and tumorigenesis: new perspectives for cancer detection and treatment

    Institute of Scientific and Technical Information of China (English)

    Danila CORADINI; Claudia CASARSA; Saro ORIANA

    2011-01-01

    Loss of cell-cell adhesion and cell polarity is commonly observed in tumors of epithelial origin and correlates with their invasion into adjacent tissues and formation of metastases. Growing evidence indicates that loss of cell polarity and cell-cell adhesion may also be important in early stage of cancer. In first part of this review, we delineate the current understanding of the mechanisms that establish and maintain the polarity of epithelial tissues and discuss the involvement of cell polarity and apical junctional complex components in tumor pathogenesis. In the second part we address the clinical significance of cell polarity and junctional complex components in can- cer diagnosis and prognosis. Finally, we explore their potential use as therapeutic targets in the treatment of cancer.

  5. Polarized Trafficking of the Sorting Receptor SorLA in Neurons and MDCK Cells

    DEFF Research Database (Denmark)

    Klinger, Stine C; Højland, Anne; Jain, Shweta;

    2016-01-01

    The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB and lipoprotein lipase...... (LpL). Despite this, only the trafficking in non-polarized cells has been described so far. Due to the many differences between polarized and non-polarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We...

  6. Rho GTPases and regulation of cell migration and polarization in human corneal epithelial cells.

    Directory of Open Access Journals (Sweden)

    Aihua Hou

    Full Text Available PURPOSE: Epithelial cell migration is required for regeneration of tissues and can be defective in a number of ocular surface diseases. This study aimed to determine the expression pattern of Rho family small G-proteins in human corneal epithelial cells to test their requirement in directional cell migration. METHODS: Rho family small G-protein expression was assessed by reverse transcription-polymerase chain reaction. Dominant-inhibitory constructs encoding Rho proteins or Rho protein targeting small interfering RNA were transfected into human corneal epithelial large T antigen cells, and wound closure rate were evaluated by scratch wounding assay, and a complementary non-traumatic cell migration assay. Immunofluorescence staining was performed to study cell polarization and to assess Cdc42 downstream effector. RESULTS: Cdc42, Chp, Rac1, RhoA, TC10 and TCL were expressed in human corneal epithelial cells. Among them, Cdc42 and TCL were found to significantly affect cell migration in monolayer scratch assays. These results were confirmed through the use of validated siRNAs directed to Cdc42 and TCL. Scramble siRNA transfected cells had high percentage of polarized cells than Cdc42 or TCL siRNA transfected cells at the wound edge. We showed that the Cdc42-specific effector p21-activated kinase 4 localized predominantly to cell-cell junctions in cell monolayers, but failed to translocate to the leading edge in Cdc42 siRNA transfected cells after monolayer wounding. CONCLUSION: Rho proteins expressed in cultured human corneal epithelial cells, and Cdc42, TCL facilitate two-dimensional cell migration in-vitro. Although silencing of Cdc42 and TCL did not noticeably affect the appearance of cell adhesions at the leading edge, the slower migration of these cells indicates both GTP-binding proteins play important roles in promoting cell movement of human corneal epithelial cells.

  7. Kif3a regulates planar polarization of auditory hair cells through both ciliary and non-ciliary mechanisms

    OpenAIRE

    Sipe, Conor W.; Lu, Xiaowei

    2011-01-01

    Auditory hair cells represent one of the most prominent examples of epithelial planar polarity. In the auditory sensory epithelium, planar polarity of individual hair cells is defined by their V-shaped hair bundle, the mechanotransduction organelle located on the apical surface. At the tissue level, all hair cells display uniform planar polarity across the epithelium. Although it is known that tissue planar polarity is controlled by non-canonical Wnt/planar cell polarity (PCP) signaling, the ...

  8. Mechanistic Framework for Establishment, Maintenance, and Alteration of Cell Polarity in Plants

    Directory of Open Access Journals (Sweden)

    Pankaj Dhonukshe

    2012-01-01

    Full Text Available Cell polarity establishment, maintenance, and alteration are central to the developmental and response programs of nearly all organisms and are often implicated in abnormalities ranging from patterning defects to cancer. By residing at the distinct plasma membrane domains polar cargoes mark the identities of those domains, and execute localized functions. Polar cargoes are recruited to the specialized membrane domains by directional secretion and/or directional endocytic recycling. In plants, auxin efflux carrier PIN proteins display polar localizations in various cell types and play major roles in directional cell-to-cell transport of signaling molecule auxin that is vital for plant patterning and response programs. Recent advanced microscopy studies applied to single cells in intact plants reveal subcellular PIN dynamics. They uncover the PIN polarity generation mechanism and identified important roles of AGC kinases for polar PIN localization. AGC kinase family members PINOID, WAG1, and WAG2, belonging to the AGC-3 subclass predominantly influence the polar localization of PINs. The emerging mechanism for AGC-3 kinases action suggests that kinases phosphorylate PINs mainly at the plasma membrane after initial symmetric PIN secretion for eventual PIN internalization and PIN sorting into distinct ARF-GEF-regulated polar recycling pathways. Thus phosphorylation status directs PIN translocation to different cell sides. Based on these findings a mechanistic framework evolves that suggests existence of cell side-specific recycling pathways in plants and implicates AGC3 kinases for differential PIN recruitment among them for eventual PIN polarity establishment, maintenance, and alteration.

  9. Kidney Specific Protein-Positive Cells Derived from Embryonic Stem Cells Reproduce Tubular Structures In Vitro and Differentiate into Renal Tubular Cells

    OpenAIRE

    Ryuji Morizane; Toshiaki Monkawa; Shizuka Fujii; Shintaro Yamaguchi; Koichiro Homma; Yumi Matsuzaki; Hideyuki Okano; Hiroshi Itoh

    2013-01-01

    Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be...

  10. Sequential development of apical-basal and planar polarities in aggregating epitheliomuscular cells of Hydra.

    Science.gov (United States)

    Seybold, Anna; Salvenmoser, Willi; Hobmayer, Bert

    2016-04-01

    Apical-basal and planar cell polarities are hallmarks of metazoan epithelia required to separate internal and external environments and to regulate trans- and intracellular transport, cytoskeletal organization, and morphogenesis. Mechanisms of cell polarization have been intensively studied in bilaterian model organisms, particularly in early embryos and cultured cells, while cell polarity in pre-bilaterian tissues is poorly understood. Here, we have studied apical-basal and planar polarization in regenerating (aggregating) clusters of epitheliomuscular cells of Hydra, a simple representative of the ancestral, pre-bilaterian phylum Cnidaria. Immediately after dissociation, single epitheliomuscular cells do not exhibit cellular polarity, but they polarize de novo during aggregation. Reestablishment of the Hydra-specific epithelial bilayer is a result of short-range cell sorting. In the early phase of aggregation, apical-basal polarization starts with an enlargement of the epithelial apical-basal diameter and by the development of belt-like apical septate junctions. Specification of the basal pole of epithelial cells occurs shortly later and is linked to synthesis of mesoglea, development of hemidesmosome-like junctions, and formation of desmosome-like junctions connecting the basal myonemes of neighbouring cells. Planar polarization starts, while apical-basal polarization is already ongoing. It is executed gradually starting with cell-autonomous formation, parallelization, and condensation of myonemes at the basal end of each epithelial cell and continuing with a final planar alignment of epitheliomuscular cells at the tissue level. Our findings reveal that epithelial polarization in Hydra aggregates occurs in defined steps well accessible by histological and ultrastructural techniques and they will provide a basis for future molecular studies. PMID:26921448

  11. Loss of Cell Adhesion Increases Tumorigenic Potential of Polarity Deficient Scribble Mutant Cells.

    Directory of Open Access Journals (Sweden)

    Indrayani Waghmare

    Full Text Available Epithelial polarity genes are important for maintaining tissue architecture, and regulating growth. The Drosophila neoplastic tumor suppressor gene scribble (scrib belongs to the basolateral polarity complex. Loss of scrib results in disruption of its growth regulatory functions, and downregulation or mislocalization of Scrib is correlated to tumor growth. Somatic scribble mutant cells (scrib- surrounded by wild-type cells undergo apoptosis, which can be prevented by introduction of secondary mutations that provide a growth advantage. Using genetic tools in Drosophila, we analyzed the phenotypic effects of loss of scrib in different growth promoting backgrounds. We investigated if a central mechanism that regulates cell adhesion governs the growth and invasive potential of scrib mutant cells. Here we show that increased proliferation, and survival abilities of scrib- cells in different genetic backgrounds affect their differentiation, and intercellular adhesion. Further, loss of scrib is sufficient to cause reduced cell survival, activation of the JNK pathway and a mild reduction of cell adhesion. Our data show that for scrib cells to induce aggressive tumor growth characterized by loss of differentiation, cell adhesion, increased proliferation and invasion, cooperative interactions that derail signaling pathways play an essential role in the mechanisms leading to tumorigenesis. Thus, our study provides new insights on the effects of loss of scrib and the modification of these effects via cooperative interactions that enhance the overall tumorigenic potential of scrib deficient cells.

  12. Kidney specific protein-positive cells derived from embryonic stem cells reproduce tubular structures in vitro and differentiate into renal tubular cells.

    Directory of Open Access Journals (Sweden)

    Ryuji Morizane

    Full Text Available Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be induced in vitro because of the complexity of kidney structures and the diversity of kidney-component cells. Here, we describe a method of inducing renal tubular cells from mouse embryonic stem cells via the cell purification of kidney specific protein (KSP-positive cells using an anti-KSP antibody. The global gene expression profiles of KSP-positive cells derived from ES cells exhibited characteristics similar to those of cells in the developing kidney, and KSP-positive cells had the capacity to form tubular structures resembling renal tubular cells when grown in a 3D culture in Matrigel. Moreover, our results indicated that KSP-positive cells acquired the characteristics of each segment of renal tubular cells through tubular formation when stimulated with Wnt4. This method is an important step toward kidney disease research using pluripotent stem cells, and the development of kidney regeneration therapies.

  13. Regulation of differentiation and polarized secretion in mammary epithelial cells maintained in culture: extracellular matrix and membrane polarity influences

    OpenAIRE

    1987-01-01

    Several previous studies have demonstrated that mammary epithelial cells from pregnant mice retain their differentiated characteristics and their secretory potential in culture only when maintained on stromal collagen gels floated in the culture medium. The cellular basis for these culture requirements was investigated by the monitoring of milk protein synthesis and polarized secretion from the mouse mammary epithelial cell line, COMMA-1-D. Experiments were directed towards gaining an underst...

  14. Competition of two distinct actin networks for actin defines a bistable switch for cell polarization

    Science.gov (United States)

    Lomakin, Alexis J.; Lee, Kun-Chun; Han, Sangyoon J.; Bui, D A.; Davidson, Michael; Mogilner, Alex; Danuser, Gaudenz

    2015-01-01

    Symmetry-breaking polarization enables functional plasticity of cells and tissues and is yet not well understood. Here we show that epithelial cells, hard-wired to maintain a static morphology and to preserve tissue organization, can spontaneously switch to a migratory polarized phenotype upon relaxation of the actomyosin cytoskeleton. We find that myosin-II engages actin in the formation of cortical actomyosin bundles and thus makes it unavailable for deployment in the process of dendritic growth normally driving cell motility. At low contractility regimes epithelial cells polarize in a front-back manner due to emergence of actin retrograde flows powered by dendritic polymerization of actin. Coupled to cell movement, the flows transport myosin-II from the front to the back of the cell, where the motor locally “locks” actin in contractile bundles. This polarization mechanism could be employed by embryonic and cancer epithelial cells in microenvironments where high contractility-driven cell motion is inefficient. PMID:26414403

  15. The Need for Reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Robey, Robert W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-27

    The purpose of this presentation is to consider issues of reproducibility, specifically it determines whether bitwise reproducible computation is possible, if computational research in DOE improves its publication process, and if reproducible results can be achieved apart from the peer review process?

  16. Positioning of polarity formation by extracellular signaling during asymmetric cell division.

    Science.gov (United States)

    Seirin Lee, Sungrim

    2016-07-01

    Anterior-posterior (AP) polarity formation of cell membrane proteins plays a crucial role in determining cell asymmetry, which ultimately generates cell diversity. In Caenorhabditis elegans, a single fertilized egg cell (P0), its daughter cell (P1), and the germline precursors (P2 and P3 cells) form two exclusive domains of different PAR proteins on the membrane along the anterior-posterior axis. However, the phenomenon of polarity reversal has been observed in which the axis of asymmetric cell division of the P2 and P3 cells is formed in an opposite manner to that of the P0 and P1 cells. The extracellular signal MES-1/SRC-1 has been shown to induce polarity reversal, but the detailed mechanism remains elusive. Here, using a mathematical model, I explore the mechanism by which MES-1/SRC-1 signaling can induce polarity reversal and ultimately affect the process of polarity formation. I show that a positive correlation between SRC-1 and the on-rate of PAR-2 is the essential mechanism underlying polarity reversal, providing a mathematical basis for the orientation of cell polarity patterns. PMID:27086039

  17. A polarized cell model for Chikungunya virus infection: entry and egress of virus occurs at the apical domain of polarized cells.

    Directory of Open Access Journals (Sweden)

    Pei Jin Lim

    2014-02-01

    Full Text Available Chikungunya virus (CHIKV has resulted in several outbreaks in the past six decades. The clinical symptoms of Chikungunya infection include fever, skin rash, arthralgia, and an increasing incidence of encephalitis. The re-emergence of CHIKV with more severe pathogenesis highlights its potential threat on our human health. In this study, polarized HBMEC, polarized Vero C1008 and non-polarized Vero cells grown on cell culture inserts were infected with CHIKV apically or basolaterally. Plaque assays, viral binding assays and immunofluorescence assays demonstrated apical entry and release of CHIKV in polarized HBMEC and Vero C1008. Drug treatment studies were performed to elucidate both host cell and viral factors involved in the sorting and release of CHIKV at the apical domain of polarized cells. Disruption of host cell myosin II, microtubule and microfilament networks did not disrupt the polarized release of CHIKV. However, treatment with tunicamycin resulted in a bi-directional release of CHIKV, suggesting that N-glycans of CHIKV envelope glycoproteins could serve as apical sorting signals.

  18. EGFR signaling promotes self-renewal through the establishment of cell polarity in Drosophila follicle stem cells.

    Science.gov (United States)

    Castanieto, Angela; Johnston, Michael J; Nystul, Todd G

    2014-01-01

    Epithelial stem cells divide asymmetrically, such that one daughter replenishes the stem cell pool and the other differentiates. We found that, in the epithelial follicle stem cell (FSC) lineage of the Drosophila ovary, epidermal growth factor receptor (EGFR) signaling functions specifically in the FSCs to promote the unique partially polarized state of the FSC, establish apical-basal polarity throughout the lineage, and promote FSC maintenance in the niche. In addition, we identified a novel connection between EGFR signaling and the cell-polarity regulator liver kinase B1 (LKB1), which indicates that EGFR signals through both the Ras-Raf-MEK-Erk pathway and through the LKB1-AMPK pathway to suppress apical identity. The development of apical-basal polarity is the earliest visible difference between FSCs and their daughters, and our findings demonstrate that the EGFR-mediated regulation of apical-basal polarity is essential for the segregation of stem cell and daughter cell fates. PMID:25437306

  19. Construction of rat glioma cell line C6-Luc for reproducing an animal model with stable expression of luciferase

    Directory of Open Access Journals (Sweden)

    Wei HUANG

    2011-01-01

    Full Text Available Objective To construct the rat glioma cell line C6-Luc to stably express the firefly luciferase.Methods The optimal concentration of hygromycin for screening C6 rat glioma cells was determined by concentration gradient method.The eukaryotic plasmid pGL4.50 expressing luciferase was transfected into C6 cells by using FuGENE HD transfection reagent,followed by screening the polyclonal cell lines with hygromycin,subsequently screening the monoclonal cell line by limited dilution.The positive monoclonal cell lines were identified with reporter gene assay,thereafter the expression stability of luciferase was investigated in the positive cell lines.The bioluminescence detection in vitro in the positive monoclonal cell line was performed to determine the minimum detection amount of cells,and the correlation between bioluminescence intensity and cell amount was analyzed by linear regression analysis.The positive monoclonal cells were implanted into the brain of Wistar rats,and the tumor growth in rats’ brain was detected in vivo using the bioluminescence imaging detection system.Results The optimal concentration of hygromycin used in screening C6 cells was 250 μg/ml.The eukaryotic plasmids pGL4.50 was successfully transfected into C6 cells,and 12 monoclonal cell lines were obtained by anti-hygromycin screening.A positive clone with the highest activity of luciferase,designated as C6-Luc,was successfully identified by using luciferase reporter gene assay,which showed a stable activity of expressing luciferase after 3 continuous passages of cultivation.The bioluminescence detection in vitro showed that the minimum detection amount of C6-Luc cells was 78.A good linear correlation existed between bioluminescence intensity and the amount of C6-Luc cells,with an equation of y=81.348x-2143.1 and correlation coefficient(r of 0.997.The in vivo bioluminescence imaging detection showed tumorigenesis could be detected after implantation of C6-Luc cells into

  20. Flotillins are involved in the polarization of primitive and mature hematopoietic cells.

    Directory of Open Access Journals (Sweden)

    Lawrence Rajendran

    Full Text Available BACKGROUND: Migration of mature and immature leukocytes in response to chemokines is not only essential during inflammation and host defense, but also during development of the hematopoietic system. Many molecules implicated in migratory polarity show uniform cellular distribution under non-activated conditions, but acquire a polarized localization upon exposure to migratory cues. METHODOLOGY/PRINCIPAL FINDINGS: Here, we present evidence that raft-associated endocytic proteins (flotillins are pre-assembled in lymphoid, myeloid and primitive hematopoietic cells and accumulate in the uropod during migration. Furthermore, flotillins display a polarized distribution during immunological synapse formation. Employing the membrane lipid-order sensitive probe Laurdan, we show that flotillin accumulation in the immunological synapse is concomittant with membrane ordering in these regions. CONCLUSIONS: Together with the observation that flotillin polarization does not occur in other polarized cell types such as polarized epithelial cells, our results suggest a specific role for flotillins in hematopoietic cell polarization. Based on our results, we propose that in hematopoietic cells, flotillins provide intrinsic cues that govern segregation of certain microdomain-associated molecules during immune cell polarization.

  1. Dystroglycan is required for polarizing the epithelial cells and the oocyte in Drosophila

    DEFF Research Database (Denmark)

    Deng, Wu-Min; Schneider, Martina; Frock, Richard;

    2003-01-01

    The transmembrane protein Dystroglycan is a central element of the dystrophin-associated glycoprotein complex, which is involved in the pathogenesis of many forms of muscular dystrophy. Dystroglycan is a receptor for multiple extracellular matrix (ECM) molecules such as Laminin, agrin and perlecan......-autonomously for cellular polarity in two different cell types, the epithelial cells (apicobasal polarity) and the oocyte (anteroposterior polarity). Loss of Dystroglycan function in follicle and disc epithelia results in expansion of apical markers to the basal side of cells and overexpression results in a...... reduced apical localization of these same markers. In Dystroglycan germline clones early oocyte polarity markers fail to be localized to the posterior, and oocyte cortical F-actin organization is abnormal. Dystroglycan is also required non-cell-autonomously to organize the planar polarity of basal actin...

  2. Capture and sorting of multiple cells by polarization-controlled three-beam interference

    Science.gov (United States)

    Hou, Yu; Wang, Zuobin; Hu, Yaowei; Li, Dayou; Qiu, Renxi

    2016-03-01

    For the capture and sorting of multiple cells, a sensitive and highly efficient polarization-controlled three-beam interference set-up has been developed. With the theory of superposition of three beams, simulations on the influence of polarization angle upon the intensity distribution and the laser gradient force change with different polarization angles have been carried out. By controlling the polarization angle of the beams, various intensity distributions and different sizes of dots are obtained. We have experimentally observed multiple optical tweezers and the sorting of cells with different polarization angles, which are in accordance with the theoretical analysis. The experimental results have shown that the polarization angle affects the shapes and feature sizes of the interference patterns and the trapping force.

  3. A two-step mechanism underlies the planar polarization of regenerating sensory hair cells

    OpenAIRE

    López-Schier, Hernán; Hudspeth, A. J.

    2006-01-01

    The restoration of planar cell polarity is an essential but poorly understood step toward physiological recovery during sensory-organ regeneration. Investigating this issue in the lateral line of the zebrafish, we found that hair cells regenerate in pairs along a single axis established by the restricted localization and oriented division of their progenitors. By analyzing mutants lacking the planar-polarity determinant Vangl2, we ascertained that the uniaxial production of hair cells and the...

  4. Advantages and mechanisms of polarity and cell shape determination in Caulobacter crescentus

    OpenAIRE

    Lawler, Melanie L.; Brun, Yves V.

    2007-01-01

    The tremendous diversity of bacterial cell shapes and the targeting of proteins and macromolecular complexes to specific subcellular sites strongly suggest that cellular organization provides important advantages for bacteria in their environment. Key advances have been made in the understanding of the mechanism and function of polarity and cell shape by studying the aquatic bacterium Caulobacter crescentus, whose cell cycle progression involves the ordered synthesis of different polar struct...

  5. The Rho GTPase Cdc42 regulates hair cell planar polarity and cellular patterning in the developing cochlea

    OpenAIRE

    Anna Kirjavainen; Maarja Laos; Tommi Anttonen; Ulla Pirvola

    2015-01-01

    Hair cells of the organ of Corti (OC) of the cochlea exhibit distinct planar polarity, both at the tissue and cellular level. Planar polarity at tissue level is manifested as uniform orientation of the hair cell stereociliary bundles. Hair cell intrinsic polarity is defined as structural hair bundle asymmetry; positioning of the kinocilium/basal body complex at the vertex of the V-shaped bundle. Consistent with strong apical polarity, the hair cell apex displays prominent actin and microtubul...

  6. Dkk-1 Inhibits Intestinal Epithelial Cell Migration by Attenuating Directional Polarization of Leading Edge Cells

    Science.gov (United States)

    Koch, Stefan; Capaldo, Christopher T.; Samarin, Stanislav; Nava, Porfirio; Neumaier, Irmgard; Skerra, Arne; Sacks, David B.; Parkos, Charles A.

    2009-01-01

    Wnt signaling pathways regulate proliferation, motility, and survival in a variety of human cell types. Dickkopf-1 (Dkk-1) is a secreted Wnt antagonist that has been proposed to regulate tissue homeostasis in the intestine. In this report, we show that Dkk-1 is secreted by intestinal epithelial cells after wounding and that it inhibits cell migration by attenuating the directional orientation of migrating epithelial cells. Dkk-1 exposure induced mislocalized activation of Cdc42 in migrating cells, which coincided with a displacement of the polarity protein Par6 from the leading edge. Consequently, the relocation of the microtubule organizing center and the Golgi apparatus in the direction of migration was significantly and persistently inhibited in the presence of Dkk-1. Small interfering RNA-induced down-regulation of Dkk-1 confirmed that extracellular exposure to Dkk-1 was required for this effect. Together, these data demonstrate a novel role of Dkk-1 in the regulation of directional polarization of migrating intestinal epithelial cells, which contributes to the effect of Dkk-1 on wound closure in vivo. PMID:19776352

  7. Cell shape, spreading symmetry, and the polarization of stress-fibers in cells

    Energy Technology Data Exchange (ETDEWEB)

    Zemel, A [Institute of Dental Sciences, Faculty of Dental Medicine, and the Fritz Haber Center for Molecular Dynamics, Hebrew University-Hadassah Medical Center, Jerusalem, 91120 (Israel); Rehfeldt, F [III. Physikalisches Institut, Georg-August-Universitaet, 37077 Goettingen (Germany); Brown, A E X [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Discher, D E [Graduate Group of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Safran, S A [Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel)

    2010-05-19

    The active regulation of cellular forces during cell adhesion plays an important role in the determination of cell size, shape, and internal structure. While on flat, homogeneous and isotropic substrates some cells spread isotropically, others spread anisotropically and assume elongated structures. In addition, in their native environment as well as in vitro experiments, the cell shape and spreading asymmetry can be modulated by the local distribution of adhesive molecules and topography of the environment. We present a simple elastic model and experiments on stem cells to explain the variation of cell size with the matrix rigidity. In addition, we predict the experimental consequences of two mechanisms of acto-myosin polarization and focus here on the effect of the cell spreading asymmetry on the regulation of the stress-fiber alignment in the cytoskeleton. We show that when cell spreading is sufficiently asymmetric the alignment of acto-myosin forces in the cell increases monotonically with the matrix rigidity; however, in general this alignment is non-monotonic, as shown previously. These results highlight the importance of the symmetry characteristics of cell spreading in the regulation of cytoskeleton structure and suggest a mechanism by which different cell types may acquire different morphologies and internal structures in different mechanical environments.

  8. Cell shape, spreading symmetry, and the polarization of stress-fibers in cells

    International Nuclear Information System (INIS)

    The active regulation of cellular forces during cell adhesion plays an important role in the determination of cell size, shape, and internal structure. While on flat, homogeneous and isotropic substrates some cells spread isotropically, others spread anisotropically and assume elongated structures. In addition, in their native environment as well as in vitro experiments, the cell shape and spreading asymmetry can be modulated by the local distribution of adhesive molecules and topography of the environment. We present a simple elastic model and experiments on stem cells to explain the variation of cell size with the matrix rigidity. In addition, we predict the experimental consequences of two mechanisms of acto-myosin polarization and focus here on the effect of the cell spreading asymmetry on the regulation of the stress-fiber alignment in the cytoskeleton. We show that when cell spreading is sufficiently asymmetric the alignment of acto-myosin forces in the cell increases monotonically with the matrix rigidity; however, in general this alignment is non-monotonic, as shown previously. These results highlight the importance of the symmetry characteristics of cell spreading in the regulation of cytoskeleton structure and suggest a mechanism by which different cell types may acquire different morphologies and internal structures in different mechanical environments.

  9. Polar release of pathogenic Old World hantaviruses from renal tubular epithelial cells

    Directory of Open Access Journals (Sweden)

    Krautkrämer Ellen

    2012-11-01

    Full Text Available Abstract Background Epithelio- and endotheliotropic viruses often exert polarized entry and release that may be responsible for viral spread and dissemination. Hantaviruses, mostly rodent-borne members of the Bunyaviridae family infect epithelial and endothelial cells of different organs leading to organ dysfunction or even failure. Endothelial and renal epithelial cells belong to the target cells of Old World hantavirus. Therefore, we examined the release of hantaviruses in several renal epithelial cell culture models. We used Vero cells that are commonly used in hantavirus studies and primary human renal epithelial cells (HREpC. In addition, we analyzed MDCKII cells, an epithelial cell line of a dog kidney, which represents a widely accepted in vitro model of polarized monolayers for their permissiveness for hantavirus infection. Results Vero C1008 and primary HREpCs were grown on porous-support filter inserts for polarization. Monolayers were infected with hantavirus Hantaan (HTNV and Puumala (PUUV virus. Supernatants from the apical and basolateral chamber of infected cells were analyzed for the presence of infectious particles by re-infection of Vero cells. Viral antigen and infectious particles of HTNV and PUUV were exclusively detected in supernatants collected from the apical chamber of infected Vero C1008 cells and HREpCs. MDCKII cells were permissive for hantavirus infection and polarized MDCKII cells released infectious hantaviral particles from the apical surface corresponding to the results of Vero and primary human epithelial cells. Conclusions Pathogenic Old World hantaviruses are released from the apical surface of different polarized renal epithelial cells. We characterized MDCKII cells as a suitable polarized cell culture model for hantavirus infection studies.

  10. A comparison of mathematical models for polarization of single eukaryotic cells in response to guided cues.

    Directory of Open Access Journals (Sweden)

    Alexandra Jilkine

    2011-04-01

    Full Text Available Polarization, a primary step in the response of an individual eukaryotic cell to a spatial stimulus, has attracted numerous theoretical treatments complementing experimental studies in a variety of cell types. While the phenomenon itself is universal, details differ across cell types, and across classes of models that have been proposed. Most models address how symmetry breaking leads to polarization, some in abstract settings, others based on specific biochemistry. Here, we compare polarization in response to a stimulus (e.g., a chemoattractant in cells typically used in experiments (yeast, amoebae, leukocytes, keratocytes, fibroblasts, and neurons, and, in parallel, responses of several prototypical models to typical stimulation protocols. We find that the diversity of cell behaviors is reflected by a diversity of models, and that some, but not all models, can account for amplification of stimulus, maintenance of polarity, adaptation, sensitivity to new signals, and robustness.

  11. Analysis of dosing regimen and reproducibility of intraspinal grafting of human spinal stem cells in immmunosuppressed minipigs

    Czech Academy of Sciences Publication Activity Database

    Usvald, Dušan; Vodička, Petr; Hlučilová, Jana; Procházka, Radek; Motlík, Jan; Kuchorova, K.; Johe, K.; Marsala, S.; Scadeng, M.; Kakinohana, O.; Navarro, R.; Santa, M.; Hefferan, M. P.; Yaksh, T.L.; Marsala, M.

    2010-01-01

    Roč. 19, č. 9 (2010), s. 1103-1122. ISSN 0963-6897 Institutional research plan: CEZ:AV0Z50450515 Keywords : minipigs * human spinal stem cells * analysis Subject RIV: FH - Neurology Impact factor: 6.204, year: 2010

  12. Vectorial insertion of apical and basolateral membrane proteins in polarized epithelial cells revealed by quantitative 3D live cell imaging

    OpenAIRE

    Hua, Wei; Sheff, David; Toomre, Derek; Mellman, Ira

    2006-01-01

    Although epithelial cells are known to exhibit a polarized distribution of membrane components, the pathways responsible for delivering membrane proteins to their appropriate domains remain unclear. Using an optimized approach to three-dimensional live cell imaging, we have visualized the transport of newly synthesized apical and basolateral membrane proteins in fully polarized filter-grown Madin–Darby canine kidney cells. We performed a detailed quantitative kinetic analysis of trans-Golgi n...

  13. Within-person reproducibility of red blood cell mercury over a 10- to 15-year period among women in the Nurses' Health Study II.

    Science.gov (United States)

    Kioumourtzoglou, Marianthi-Anna; Roberts, Andrea L; Nielsen, Flemming; Tworoger, Shelley S; Grandjean, Philippe; Weisskopf, Marc G

    2016-01-01

    Most epidemiologic studies of methylmercury (MeHg) health effects rely on a single measurement of a MeHg biomarker to assess long-term exposures. Long-term reproducibility data are, therefore, needed to assess the reliability of a single measure to reflect long-term exposures. In this study, we assessed within-person reproducibility of red blood cell (RBC) mercury (Hg), a marker of methyl-mercury, over 10-15 years in a sample of 57 women. Fifty-seven women from the Nurses' Health Study II provided two blood samples 10-15-years apart (median: 12 years), which were analyzed for mercury levels in the red blood cells (B-Hg*). To characterize within-person reproducibility, we estimated correlation and intraclass correlation coefficients (r and ICC) across the two samples. Further, we compared different prediction models, including variables on fish and seafood consumption, for B-Hg* at the first sample, using leave-one-out cross-validation to assess predictive ability. Overall, we observed strong correlations over 10-15 years (r=0.69), as well as a high ICC (0.67; 95% CI: 0.49, 0.79). Fish and seafood consumption reported concurrently with the first B-Hg* sample accounted for 26.8% of the variability in that B-Hg*, giving a correlation of r=0.52. Despite decreasing B-Hg* levels over time, we observed strong correlations and high ICC estimates across B-Hg* measured 10-15 years apart, suggesting good relative within-person stability over time. Our results indicate that a single measurement of B-Hg* likely is adequate to represent long-term exposures. PMID:25492240

  14. Induced differentiation of cancer cells: second generation potent hybrid polar compounds target cell cycle regulators

    International Nuclear Information System (INIS)

    Hybrid polar compounds are potent inducers of differentiation of a wide variety of cancer transformed cells. Hexamethylene bisacetamide (HMBA) has been used as a prototype of these compounds to investigate their mechanism of action. Employing murine erythroleukemia (MEL) cells as a model, three characteristics of inducer-mediated commitment to terminal differentiation were demonstrated: (I) induced commitment was stochastic, requiring up to 5 cell cycles to recruit essentially all cells to commit to growth arrest in G1; (II) inducers caused a prolongation of the initial G1; and (III) the hybrid polar compounds induced a wide variety of transformed cells to terminal differentiation. These findings suggested that the rate limiting factor or factors for induction by these agents may be at the level of protein(s) regulating G1-to-S progression, which are common to most eukaryotic cells. It was found that HMBA induced a profound suppression of cyclin dependent kinase, cdk4, which reflected a marked decrease in stability of the protein, and is a critical change in the pathway of induced differentiation. HMBA also induced an increase in pRB and in the active, underphosphorylated form of this protein, an increase in the pRB related protein, p107, and an increase in the cyclin dependent kinase inhibitor, p21. Further, the free form of the transcription factor, E2F, was markedly decreased within hours of exposure of transformed cells to HMBA and found to complex with p107 and cdk 2. A phase II clinical trial was conducted using HMBA to treat patients with myelodysplastic syndrome (MDS) or acute myelogenous leukemia. Of 28 patients, 9 patients achieved a complete or partial remission lasting from 1 to 16 months. These clinical studies also provided direct evidence that HMBA induces differentiation of transformed cells in patients. In four separate courses of treatment with HMBA, a patient with MDS and the monosomy 7 karyotype marking the malignant clone of bone marrow blast

  15. Long-term trends of the Polar and Arctic cells influencing the Arctic climate since 1989

    Science.gov (United States)

    Qian, Weihong; Wu, Kaijun; Leung, Jeremy Cheuk-Hin; Shi, Jian

    2016-03-01

    The strengthening and broadening trends of the Hadley cell have been revealed, while the existence of the Arctic cell has also been confirmed in previous studies. This study extends previous strengthening trend analyses of the Hadley cell to the Polar and Arctic cells in the Northern Hemisphere and explores their climate influences. Results show that the Polar cell experienced an abrupt change from a slow to a rapid strengthening trend in 1989, while the Arctic cell showed an insignificant strengthening trend and a significant weakening trend successively. The strengthening subsidence flow associated with the Polar and Arctic cells can partly explain the warming surface air temperature and declining sea ice concentration through the increasing tropospheric height and temperature trends. These results provide new insights for understanding the interdecadal relationship between atmospheric circulation and climate change in the Arctic region.

  16. The young and happy marriage of membrane traffic and cell polarity

    OpenAIRE

    Thompson, Barry J; Perez, Franck; Vaccari, Thomas

    2012-01-01

    The ESF–EMBO Meeting on ‘Cell polarity and Membrane Traffic' took place in April 2012. It brought together scientists from two once very separate fields and highlighted the emerging interdependence between them.

  17. A robust and reproducible animal serum-free culture method for clinical-grade bone marrow-derived mesenchymal stromal cells.

    Science.gov (United States)

    Laitinen, Anita; Oja, Sofia; Kilpinen, Lotta; Kaartinen, Tanja; Möller, Johanna; Laitinen, Saara; Korhonen, Matti; Nystedt, Johanna

    2016-08-01

    Efficient xenofree expansion methods to replace fetal bovine serum (FBS)-based culture methods are strongly encouraged by the regulators and are needed to facilitate the adoption of mesenchymal stromal cell (MSC)-based therapies. In the current study we established a clinically-compliant and reproducible animal serum-free culture protocol for bone marrow-(BM-) MSCs based on an optimized platelet-derived supplement. Our study compared two different platelet-derived supplements, platelet lysate PL1 versus PL2, produced by two different methods and lysed with different amounts of freeze-thaw cycles. Our study also explored the effect of a low oxygen concentration on BM-MSCs. FBS-supplemented BM-MSC culture served as control. Growth kinetics, differentiation and immunomodulatory potential, morphology, karyotype and immunophenotype was analysed. Growth kinetics in long-term culture was also studied. Based on the initial results, we chose to further process develop the PL1-supplemented culture protocol at 20 % oxygen. The results from 11 individual BM-MSC batches expanded in the chosen condition were consistent, yielding 6.60 × 10(9) ± 4.74 × 10(9) cells from only 20 ml of bone marrow. The cells suppressed T-cell proliferation, displayed normal karyotype and typical MSC differentiation potential and phenotype. The BM-MSCs were, however, consistently HLA-DR positive when cultured in platelet lysate (7.5-66.1 %). We additionally show that culture media antibiotics and sterile filtration of the platelet lysate can be successfully omitted. We present a robust and reproducible clinically-compliant culture method for BM-MSCs based on platelet lysate, which enables high quantities of HLA-DR positive MSCs at a low passage number (p2) and suitable for clinical use. PMID:25777046

  18. Replacement of the cytoplasmic domain alters sorting of a viral glycoprotein in polarized cells.

    OpenAIRE

    Puddington, L; Woodgett, C; Rose, J. K.

    1987-01-01

    The envelope glycoprotein (G protein) of vesicular stomatitis virus (VSV) is transported to the basolateral plasma membrane of polarized epithelial cells, whereas the hemagglutinin glycoprotein (HA protein) of influenza virus is transported to the apical plasma membrane. To determine if the cytoplasmic domain of VSV G protein might be important in directing G protein to the basolateral membrane, we derived polarized Madin-Darby canine kidney cell lines expressing G protein or G protein with i...

  19. Cdc42 and noncanonical Wnt signal transduction pathways cooperate to promote cell polarity

    OpenAIRE

    Schlessinger, Karni; McManus, Edward J.; Hall, Alan

    2007-01-01

    Scratch-induced disruption of cultured monolayers induces polarity in front row cells that can be visualized by spatially localized polymerization of actin at the front of the cell and reorientation of the centrosome/Golgi to face the leading edge. We previously reported that centrosomal reorientation and microtubule polarization depend on a Cdc42-regulated signal transduction pathway involving activation of the Par6/aPKC complex followed by inhibition of GSK-3β and accumulation of the adenom...

  20. A simple protocol for amino acid type selective isotope labeling in insect cells with improved yields and high reproducibility

    International Nuclear Information System (INIS)

    An easy to use and robust approach for amino acid type selective isotope labeling in insect cells is presented. It relies on inexpensive commercial media and can be implemented in laboratories without sophisticated infrastructure. In contrast to previous protocols, where either high protein amounts or high incorporation ratios were obtained, here we achieve both at the same time. By supplementing media with a well considered amount of yeast extract, similar protein amounts as with full media are obtained, without compromising on isotope incorporation. In single and dual amino acid labeling experiments incorporation ratios are consistently ≥90% for all amino acids tested. This enables NMR studies of eukaryotic proteins and their interactions even for proteins with low expression levels. We show applications with human kinases, where protein–ligand interactions are characterized by 2D [15N, 1H]- and [13C, 1H]-HSQC spectra.

  1. Local Pheromone Release from Dynamic Polarity Sites Underlies Cell-Cell Pairing during Yeast Mating.

    Science.gov (United States)

    Merlini, Laura; Khalili, Bita; Bendezú, Felipe O; Hurwitz, Daniel; Vincenzetti, Vincent; Vavylonis, Dimitrios; Martin, Sophie G

    2016-04-25

    Cell pairing is central for many processes, including immune defense, neuronal connection, hyphal fusion, and sexual reproduction. How does a cell orient toward a partner, especially when faced with multiple choices? Fission yeast Schizosaccharomyces pombe P and M cells, which respectively express P and M factor pheromones [1, 2], pair during the mating process induced by nitrogen starvation. Engagement of pheromone receptors Map3 and Mam2 [3, 4] with their cognate pheromone ligands leads to activation of the Gα protein Gpa1 to signal sexual differentiation [3, 5, 6]. Prior to cell pairing, the Cdc42 GTPase, a central regulator of cell polarization, forms dynamic zones of activity at the cell periphery at distinct locations over time [7]. Here we show that Cdc42-GTP polarization sites contain the M factor transporter Mam1, the general secretion machinery, which underlies P factor secretion, and Gpa1, suggesting that these are sub-cellular zones of pheromone secretion and signaling. Zone lifetimes scale with pheromone concentration. Computational simulations of pair formation through a fluctuating zone show that the combination of local pheromone release and sensing, short pheromone decay length, and pheromone-dependent zone stabilization leads to efficient pair formation. Consistently, pairing efficiency is reduced in the absence of the P factor protease. Similarly, zone stabilization at reduced pheromone levels, which occurs in the absence of the predicted GTPase-activating protein for Ras, leads to reduction in pairing efficiency. We propose that efficient cell pairing relies on fluctuating local signal emission and perception, which become locked into place through stimulation. PMID:27020743

  2. Myosin Id is required for planar cell polarity in ciliated tracheal and ependymal epithelial cells.

    Science.gov (United States)

    Hegan, Peter S; Ostertag, Eric; Geurts, Aron M; Mooseker, Mark S

    2015-10-01

    In wild type (WT) tracheal epithelial cells, ciliary basal bodies are oriented such that all cilia on the cell surface beat in the same upward direction. This precise alignment of basal bodies and, as a result, the ciliary axoneme, is termed rotational planar cell polarity (PCP). Rotational PCP in the multi-ciliated epithelial cells of the trachea is perturbed in rats lacking myosin Id (Myo1d). Myo1d is localized in the F-actin and basal body rich subapical cortex of the ciliated tracheal epithelial cell. Scanning and transmission electron microscopy of Myo1d knock out (KO) trachea revealed that the unidirectional bending pattern is disrupted. Instead, cilia splay out in a disordered, often radial pattern. Measurement of the alignment axis of the central pair axonemal microtubules was much more variable in the KO, another indicator that rotational PCP is perturbed. The asymmetric localization of the PCP core protein Vangl1 is lost. Both the velocity and linearity of cilia-driven movement of beads above the tracheal mucosal surface was impaired in the Myo1d KO. Multi-ciliated brain ependymal epithelial cells exhibit a second form of PCP termed translational PCP in which basal bodies and attached cilia are clustered at the anterior side of the cell. The precise asymmetric clustering of cilia is disrupted in the ependymal cells of the Myo1d KO rat. While basal body clustering is maintained, left-right positioning of the clusters is lost. PMID:26446290

  3. Intra- and inter-laboratory reproducibility and accuracy of the LuSens assay: A reporter gene-cell line to detect keratinocyte activation by skin sensitizers.

    Science.gov (United States)

    Ramirez, Tzutzuy; Stein, Nadine; Aumann, Alexandra; Remus, Tina; Edwards, Amber; Norman, Kimberly G; Ryan, Cindy; Bader, Jackie E; Fehr, Markus; Burleson, Florence; Foertsch, Leslie; Wang, Xiaohong; Gerberick, Frank; Beilstein, Paul; Hoffmann, Sebastian; Mehling, Annette; van Ravenzwaay, Bennard; Landsiedel, Robert

    2016-04-01

    Several non-animal methods are now available to address the key events leading to skin sensitization as defined by the adverse outcome pathway. The KeratinoSens assay addresses the cellular event of keratinocyte activation and is a method accepted under OECD TG 442D. In this study, the results of an inter-laboratory evaluation of the "me-too" LuSens assay, a bioassay that uses a human keratinocyte cell line harboring a reporter gene construct composed of the rat antioxidant response element (ARE) of the NADPH:quinone oxidoreductase 1 gene and the luciferase gene, are described. Earlier in-house validation with 74 substances showed an accuracy of 82% in comparison to human data. When used in a battery of non-animal methods, even higher predictivity is achieved. To meet European validation criteria, a multicenter study was conducted in 5 laboratories. The study was divided into two phases, to assess 1) transferability of the method, and 2) reproducibility and accuracy. Phase I was performed by testing 8 non-coded test substances; the results showed a good transferability to naïve laboratories even without on-site training. Phase II was performed with 20 coded test substances (performance standards recommended by OECD, 2015). In this phase, the intra- and inter-laboratory reproducibility as well as accuracy of the method was evaluated. The data demonstrate a remarkable reproducibility of 100% and an accuracy of over 80% in identifying skin sensitizers, indicating a good concordance with in vivo data. These results demonstrate good transferability, reliability and accuracy of the method thereby achieving the standards necessary for use in a regulatory setting to detect skin sensitizers. PMID:26796489

  4. Porcine aminopeptidase N mediated polarized infection by porcine epidemic diarrhea virus in target cells

    International Nuclear Information System (INIS)

    Infection of polarized intestinal epithelial cells by porcine epidemic diarrhea virus (PEDV) was characterized. Indirect immunofluorescence assay, real-time PCR, and transmission electron microscopy confirmed PEDV can be successfully propagated in immortalized swine small intestine epithelial cells (IECs). Infection involved porcine aminpeptidase N (pAPN), a reported cellular receptor for PEDV, transient expression of pAPN and siRNA targeted pAPN increased and decreased the infectivity of PEDV in IECs, respectively. Subsequently, polarized entry into and release from both Vero E6 and IECs was analyzed. PEDV entry into polarized cells and pAPN grown on membrane inserts occurs via apical membrane. The progeny virus released into the medium was also quantified which demonstrated that PEDV is preferentially released from the apical membrane. Collectively, our data demonstrate that pAPN, the cellular receptor for PEDV, mediates polarized PEDV infection. These results imply the possibility that PEDV infection may proceed by lateral spread of virus in intestinal epithelial cells. - Highlights: • PEDV infection of polarized intestinal epithelial cells (IECs) was characterized. • Porcine aminpeptidase N (pAPN) facilitated PEDV infection in IECs. • PEDV entry into and release from polarized cell via its apical membrane. • PEDV infection may proceed by lateral spread of virus in IECs

  5. Porcine aminopeptidase N mediated polarized infection by porcine epidemic diarrhea virus in target cells

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Yingying; Li, Xiaoxue; Bai, Yunyun [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); Lv, Xiaonan [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience & Technology of China, Beijing 100090 (China); Herrler, Georg [Institute for Virology, University of Veterinary Medicine, Hannover D-30559 (Germany); Enjuanes, Luis [Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid (Spain); Zhou, Xingdong [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); Qu, Bo [Faculty of Life Sciences, Northeast Agricultural University, Harbin 150030 (China); Meng, Fandan [Institute for Virology, University of Veterinary Medicine, Hannover D-30559 (Germany); Cong, Chengcheng [College Animal Husbandry and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110161 (China); Ren, Xiaofeng; Li, Guangxing [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China)

    2015-04-15

    Infection of polarized intestinal epithelial cells by porcine epidemic diarrhea virus (PEDV) was characterized. Indirect immunofluorescence assay, real-time PCR, and transmission electron microscopy confirmed PEDV can be successfully propagated in immortalized swine small intestine epithelial cells (IECs). Infection involved porcine aminpeptidase N (pAPN), a reported cellular receptor for PEDV, transient expression of pAPN and siRNA targeted pAPN increased and decreased the infectivity of PEDV in IECs, respectively. Subsequently, polarized entry into and release from both Vero E6 and IECs was analyzed. PEDV entry into polarized cells and pAPN grown on membrane inserts occurs via apical membrane. The progeny virus released into the medium was also quantified which demonstrated that PEDV is preferentially released from the apical membrane. Collectively, our data demonstrate that pAPN, the cellular receptor for PEDV, mediates polarized PEDV infection. These results imply the possibility that PEDV infection may proceed by lateral spread of virus in intestinal epithelial cells. - Highlights: • PEDV infection of polarized intestinal epithelial cells (IECs) was characterized. • Porcine aminpeptidase N (pAPN) facilitated PEDV infection in IECs. • PEDV entry into and release from polarized cell via its apical membrane. • PEDV infection may proceed by lateral spread of virus in IECs.

  6. The viral spike protein is not involved in the polarized sorting of coronaviruses in epithelial cells

    NARCIS (Netherlands)

    Rossen, J W; de Beer, R; Godeke, G J; Raamsman, M J; Horzinek, M C; Vennema, H; Rottier, P J

    1998-01-01

    Coronaviruses are assembled by budding into a pre-Golgi compartment from which they are transported along the secretory pathway to leave the cell. In cultured epithelial cells, they are released in a polarized fashion; depending on the virus and cell type, they are sorted preferentially either to th

  7. Polarization of cells and soft objects driven by mechanical interactions: Consequences for migration and chemotaxis

    Science.gov (United States)

    Leoni, M.; Sens, P.

    2015-02-01

    We study a generic model for the polarization and motility of self-propelled soft objects, biological cells, or biomimetic systems, interacting with a viscous substrate. The active forces generated by the cell on the substrate are modeled by means of oscillating force multipoles at the cell-substrate interface. Symmetry breaking and cell polarization for a range of cell sizes naturally "emerge" from long range mechanical interactions between oscillating units, mediated both by the intracellular medium and the substrate. However, the harnessing of cell polarization for motility requires substrate-mediated interactions. Motility can be optimized by adapting the oscillation frequency to the relaxation time of the system or when the substrate and cell viscosities match. Cellular noise can destroy mechanical coordination between force-generating elements within the cell, resulting in sudden changes of polarization. The persistence of the cell's motion is found to depend on the cell size and the substrate viscosity. Within such a model, chemotactic guidance of cell motion is obtained by directionally modulating the persistence of motion, rather than by modulating the instantaneous cell velocity, in a way that resembles the run and tumble chemotaxis of bacteria.

  8. Reproducibility in Seismic Imaging

    Directory of Open Access Journals (Sweden)

    González-Verdejo O.

    2012-04-01

    Full Text Available Within the field of exploration seismology, there is interest at national level of integrating reproducibility in applied, educational and research activities related to seismic processing and imaging. This reproducibility implies the description and organization of the elements involved in numerical experiments. Thus, a researcher, teacher or student can study, verify, repeat, and modify them independently. In this work, we document and adapt reproducibility in seismic processing and imaging to spread this concept and its benefits, and to encourage the use of open source software in this area within our academic and professional environment. We present an enhanced seismic imaging example, of interest in both academic and professional environments, using Mexican seismic data. As a result of this research, we prove that it is possible to assimilate, adapt and transfer technology at low cost, using open source software and following a reproducible research scheme.

  9. Regulation of cell polarity determinants by the Retinoblastoma tumor suppressor protein.

    Science.gov (United States)

    Payankaulam, Sandhya; Yeung, Kelvin; McNeill, Helen; Henry, R William; Arnosti, David N

    2016-01-01

    In addition to their canonical roles in the cell cycle, RB family proteins regulate numerous developmental pathways, although the mechanisms remain obscure. We found that Drosophila Rbf1 associates with genes encoding components of the highly conserved apical-basal and planar cell polarity pathways, suggesting a possible regulatory role. Here, we show that depletion of Rbf1 in Drosophila tissues is indeed associated with polarity defects in the wing and eye. Key polarity genes aPKC, par6, vang, pk, and fmi are upregulated, and an aPKC mutation suppresses the Rbf1-induced phenotypes. RB control of cell polarity may be an evolutionarily conserved function, with important implications in cancer metastasis. PMID:26971715

  10. The final cut: cell polarity meets cytokinesis at the bud neck in S. cerevisiae.

    Science.gov (United States)

    Juanes, Maria Angeles; Piatti, Simonetta

    2016-08-01

    Cell division is a fundamental but complex process that gives rise to two daughter cells. It includes an ordered set of events, altogether called "the cell cycle", that culminate with cytokinesis, the final stage of mitosis leading to the physical separation of the two daughter cells. Symmetric cell division equally partitions cellular components between the two daughter cells, which are therefore identical to one another and often share the same fate. In many cases, however, cell division is asymmetrical and generates two daughter cells that differ in specific protein inheritance, cell size, or developmental potential. The budding yeast Saccharomyces cerevisiae has proven to be an excellent system to investigate the molecular mechanisms governing asymmetric cell division and cytokinesis. Budding yeast is highly polarized during the cell cycle and divides asymmetrically, producing two cells with distinct sizes and fates. Many components of the machinery establishing cell polarization during budding are relocalized to the division site (i.e., the bud neck) for cytokinesis. In this review we recapitulate how budding yeast cells undergo polarized processes at the bud neck for cell division. PMID:27085703

  11. Differential effects of Mycobacterium bovis - derived polar and apolar lipid fractions on bovine innate immune cells

    Directory of Open Access Journals (Sweden)

    Pirson Chris

    2012-06-01

    Full Text Available Abstract Mycobacterial lipids have long been known to modulate the function of a variety of cells of the innate immune system. Here, we report the extraction and characterisation of polar and apolar free lipids from Mycobacterium bovis AF 2122/97 and identify the major lipids present in these fractions. Lipids found included trehalose dimycolate (TDM and trehalose monomycolate (TMM, the apolar phthiocerol dimycocersates (PDIMs, triacyl glycerol (TAG, pentacyl trehalose (PAT, phenolic glycolipid (PGL, and mono-mycolyl glycerol (MMG. Polar lipids identified included glucose monomycolate (GMM, diphosphatidyl glycerol (DPG, phenylethanolamine (PE and a range of mono- and di-acylated phosphatidyl inositol mannosides (PIMs. These lipid fractions are capable of altering the cytokine profile produced by fresh and cultured bovine monocytes as well as monocyte derived dendritic cells. Significant increases in the production of IL-10, IL-12, MIP-1β, TNFα and IL-6 were seen after exposure of antigen presenting cells to the polar lipid fraction. Phenotypic characterisation of the cells was performed by flow cytometry and significant decreases in the expression of MHCII, CD86 and CD1b were found after exposure to the polar lipid fraction. Polar lipids also significantly increased the levels of CD40 expressed by monocytes and cultured monocytes but no effect was seen on the constitutively high expression of CD40 on MDDC or on the levels of CD80 expressed by any of the cells. Finally, the capacity of polar fraction treated cells to stimulate alloreactive lymphocytes was assessed. Significant reduction in proliferative activity was seen after stimulation of PBMC by polar fraction treated cultured monocytes whilst no effect was seen after lipid treatment of MDDC. These data demonstrate that pathogenic mycobacterial polar lipids may significantly hamper the ability of the host APCs to induce an appropriate immune response to an invading pathogen.

  12. Mammalian aPKC/Par polarity complex mediated regulation of epithelial division orientation and cell fate

    International Nuclear Information System (INIS)

    Oriented cell division is a key regulator of tissue architecture and crucial for morphogenesis and homeostasis. Balanced regulation of proliferation and differentiation is an essential property of tissues not only to drive morphogenesis but also to maintain and restore homeostasis. In many tissues orientation of cell division is coupled to the regulation of differentiation producing daughters with similar (symmetric cell division, SCD) or differential fate (asymmetric cell division, ACD). This allows the organism to generate cell lineage diversity from a small pool of stem and progenitor cells. Division orientation and/or the ratio of ACD/SCD need to be tightly controlled. Loss of orientation or an altered ratio can promote overgrowth, alter tissue architecture and induce aberrant differentiation, and have been linked to morphogenetic diseases, cancer and aging. A key requirement for oriented division is the presence of a polarity axis, which can be established through cell intrinsic and/or extrinsic signals. Polarity proteins translate such internal and external cues to drive polarization. In this review we will focus on the role of the polarity complex aPKC/Par3/Par6 in the regulation of division orientation and cell fate in different mammalian epithelia. We will compare the conserved function of this complex in mitotic spindle orientation and distribution of cell fate determinants and highlight common and differential mechanisms in which this complex is used by tissues to adapt division orientation and cell fate to the specific properties of the epithelium

  13. Mammalian aPKC/Par polarity complex mediated regulation of epithelial division orientation and cell fate

    Energy Technology Data Exchange (ETDEWEB)

    Vorhagen, Susanne; Niessen, Carien M., E-mail: carien.niessen@uni-koeln.de

    2014-11-01

    Oriented cell division is a key regulator of tissue architecture and crucial for morphogenesis and homeostasis. Balanced regulation of proliferation and differentiation is an essential property of tissues not only to drive morphogenesis but also to maintain and restore homeostasis. In many tissues orientation of cell division is coupled to the regulation of differentiation producing daughters with similar (symmetric cell division, SCD) or differential fate (asymmetric cell division, ACD). This allows the organism to generate cell lineage diversity from a small pool of stem and progenitor cells. Division orientation and/or the ratio of ACD/SCD need to be tightly controlled. Loss of orientation or an altered ratio can promote overgrowth, alter tissue architecture and induce aberrant differentiation, and have been linked to morphogenetic diseases, cancer and aging. A key requirement for oriented division is the presence of a polarity axis, which can be established through cell intrinsic and/or extrinsic signals. Polarity proteins translate such internal and external cues to drive polarization. In this review we will focus on the role of the polarity complex aPKC/Par3/Par6 in the regulation of division orientation and cell fate in different mammalian epithelia. We will compare the conserved function of this complex in mitotic spindle orientation and distribution of cell fate determinants and highlight common and differential mechanisms in which this complex is used by tissues to adapt division orientation and cell fate to the specific properties of the epithelium.

  14. Protocadherin FAT1 binds Ena/VASP proteins and is necessary for actin dynamics and cell polarization

    OpenAIRE

    Moeller, Marcus J.; Soofi, Abdulsalam; Braun, Gerald S; Li, Xiaodong; Watzl, Carsten; Kriz, Wilhelm; Holzman, Lawrence B.

    2004-01-01

    Cell migration requires integration of cellular processes resulting in cell polarization and actin dynamics. Previous work using tools of Drosophila genetics suggested that protocadherin fat serves in a pathway necessary for determining cell polarity in the plane of a tissue. Here we identify mammalian FAT1 as a proximal element of a signaling pathway that determines both cellular polarity in the plane of the monolayer and directed actin-dependent cell motility. FAT1 is localized to the leadi...

  15. Calponin 2 Acts As an Effector of Noncanonical Wnt-Mediated Cell Polarization during Neural Crest Cell Migration

    OpenAIRE

    Bärbel Ulmer; Cathrin Hagenlocher; Silke Schmalholz; Sabrina Kurz; Axel Schweickert; Ayelet Kohl; Lee Roth; Dalit Sela-Donenfeld; Martin Blum

    2013-01-01

    Neural crest cells (NCCs) migrate throughout the embryo to differentiate into cell types of all germ layers. Initial directed NCC emigration relies on planar cell polarity (PCP), which through the activity of the small GTPases RhoA and Rac governs the actin-driven formation of polarized cell protrusions. We found that the actin binding protein calponin 2 (Cnn2) was expressed in protrusions at the leading edge of migratory NCCs in chicks and frogs. Cnn2 knockdown resulted in NCC migration defe...

  16. Specific polar subpopulations of astral microtubules control spindle orientation and symmetric neural stem cell division.

    Science.gov (United States)

    Mora-Bermúdez, Felipe; Matsuzaki, Fumio; Huttner, Wieland B

    2014-01-01

    Mitotic spindle orientation is crucial for symmetric vs asymmetric cell division and depends on astral microtubules. Here, we show that distinct subpopulations of astral microtubules exist, which have differential functions in regulating spindle orientation and division symmetry. Specifically, in polarized stem cells of developing mouse neocortex, astral microtubules reaching the apical and basal cell cortex, but not those reaching the central cell cortex, are more abundant in symmetrically than asymmetrically dividing cells and reduce spindle orientation variability. This promotes symmetric divisions by maintaining an apico-basal cleavage plane. The greater abundance of apical/basal astrals depends on a higher concentration, at the basal cell cortex, of LGN, a known spindle-cell cortex linker. Furthermore, newly developed specific microtubule perturbations that selectively decrease apical/basal astrals recapitulate the symmetric-to-asymmetric division switch and suffice to increase neurogenesis in vivo. Thus, our study identifies a novel link between cell polarity, astral microtubules, and spindle orientation in morphogenesis. PMID:24996848

  17. A Three-Dimensional Cell Culture Model To Study Enterovirus Infection of Polarized Intestinal Epithelial Cells.

    Science.gov (United States)

    Drummond, Coyne G; Nickerson, Cheryl A; Coyne, Carolyn B

    2016-01-01

    Despite serving as the primary entry portal for coxsackievirus B (CVB), little is known about CVB infection of the intestinal epithelium, owing at least in part to the lack of suitable in vivo models and the inability of cultured cells to recapitulate the complexity and structure associated with the gastrointestinal (GI) tract. Here, we report on the development of a three-dimensional (3-D) organotypic cell culture model of Caco-2 cells to model CVB infection of the gastrointestinal epithelium. We show that Caco-2 cells grown in 3-D using the rotating wall vessel (RWV) bioreactor recapitulate many of the properties of the intestinal epithelium, including the formation of well-developed tight junctions, apical-basolateral polarity, brush borders, and multicellular complexity. In addition, transcriptome analyses using transcriptome sequencing (RNA-Seq) revealed the induction of a number of genes associated with intestinal epithelial differentiation and/or intestinal processes in vivo when Caco-2 cells were cultured in 3-D. Applying this model to CVB infection, we found that although the levels of intracellular virus production were similar in two-dimensional (2-D) and 3-D Caco-2 cell cultures, the release of infectious CVB was enhanced in 3-D cultures at early stages of infection. Unlike CVB, the replication of poliovirus (PV) was significantly reduced in 3-D Caco-2 cell cultures. Collectively, our studies show that Caco-2 cells grown in 3-D using the RWV bioreactor provide a cell culture model that structurally and transcriptionally represents key aspects of cells in the human GI tract and can thus be used to expand our understanding of enterovirus-host interactions in intestinal epithelial cells. IMPORTANCE Coxsackievirus B (CVB), a member of the enterovirus family of RNA viruses, is associated with meningitis, pericarditis, diabetes, dilated cardiomyopathy, and myocarditis, among other pathologies. CVB is transmitted via the fecal-oral route and encounters the

  18. A Three-Dimensional Cell Culture Model To Study Enterovirus Infection of Polarized Intestinal Epithelial Cells

    Science.gov (United States)

    Drummond, Coyne G.

    2015-01-01

    ABSTRACT Despite serving as the primary entry portal for coxsackievirus B (CVB), little is known about CVB infection of the intestinal epithelium, owing at least in part to the lack of suitable in vivo models and the inability of cultured cells to recapitulate the complexity and structure associated with the gastrointestinal (GI) tract. Here, we report on the development of a three-dimensional (3-D) organotypic cell culture model of Caco-2 cells to model CVB infection of the gastrointestinal epithelium. We show that Caco-2 cells grown in 3-D using the rotating wall vessel (RWV) bioreactor recapitulate many of the properties of the intestinal epithelium, including the formation of well-developed tight junctions, apical-basolateral polarity, brush borders, and multicellular complexity. In addition, transcriptome analyses using transcriptome sequencing (RNA-Seq) revealed the induction of a number of genes associated with intestinal epithelial differentiation and/or intestinal processes in vivo when Caco-2 cells were cultured in 3-D. Applying this model to CVB infection, we found that although the levels of intracellular virus production were similar in two-dimensional (2-D) and 3-D Caco-2 cell cultures, the release of infectious CVB was enhanced in 3-D cultures at early stages of infection. Unlike CVB, the replication of poliovirus (PV) was significantly reduced in 3-D Caco-2 cell cultures. Collectively, our studies show that Caco-2 cells grown in 3-D using the RWV bioreactor provide a cell culture model that structurally and transcriptionally represents key aspects of cells in the human GI tract and can thus be used to expand our understanding of enterovirus-host interactions in intestinal epithelial cells. IMPORTANCE Coxsackievirus B (CVB), a member of the enterovirus family of RNA viruses, is associated with meningitis, pericarditis, diabetes, dilated cardiomyopathy, and myocarditis, among other pathologies. CVB is transmitted via the fecal-oral route and

  19. Climatic anomalous patterns associated with the Arctic and Polar cell strength variations

    Science.gov (United States)

    Qian, Weihong; Wu, Kaijun; Leung, Jeremy Cheuk-Hin

    2016-03-01

    The Arctic cell as a reversed and closed loop next to the Polar cell has been recently revealed in the Northern Hemisphere (NH). In this paper, we study the interannual variability of the Arctic and Polar cell strengths during 1979-2012, and their influence on surface air temperature (SAT), precipitation, and sea-ice concentration (SIC) at mid- and high-latitudes of the NH. We show that there is a significant negative correlation between the Arctic and Polar cell strengths. Both the Arctic and Polar cell strengths can well indicate the recurring climatic anomalies of SAT, precipitation, and SIC in their extreme winters. The surface large-scale cold-warm and dry-wet anomalous patterns in these extreme winters are directly linked with the vertical structure of height and temperature anomalies in the troposphere. Results suggest that the past climatic anomalies are better indicated by the strength anomalies of the Polar and Arctic cells than the traditional indices of mid-high latitude pattern such as the Arctic Oscillation and North Atlantic Oscillation. This study illustrates a three-dimensional picture of atmospheric variable anomalies in the troposphere that result in surface climatic anomalies.

  20. The tumor suppressor Apc controls planar cell polarities central to gut homeostasis

    OpenAIRE

    Bellis, Julien; Duluc, Isabelle; Romagnolo, Béatrice; Perret, Christine; Faux, Maree C.; Dujardin, Denis; Formstone, Caroline; Lightowler, Sally; Ramsay, Robert G.; Freund, Jean-Noël; De Mey, Jan R.

    2012-01-01

    The stem cells (SCs) at the bottom of intestinal crypts tightly contact niche-supporting cells and fuel the extraordinary tissue renewal of intestinal epithelia. Their fate is regulated stochastically by populational asymmetry, yet whether asymmetrical fate as a mode of SC division is relevant and whether the SC niche contains committed progenitors of the specialized cell types are under debate. We demonstrate spindle alignments and planar cell polarities, which form a novel functional unit t...

  1. Polarization Affects Airway Epithelial Conditioning of Monocyte-Derived Dendritic Cells

    DEFF Research Database (Denmark)

    Papazian, Dick; Chhoden, Tashi; Arge, Maria;

    2015-01-01

    Airway epithelial cells (AECs) form polarized barriers that interact with inhaled allergens and are involved in immune homeostasis. We examined how monocyte-derived dendritic cells (MDDCs) are affected by contact with the airway epithelium. In traditional setups, bronchial epithelial cell lines...... were allowed to polarize on filter inserts, and MDDCs were allowed to adhere to the epithelial basal side. In an optimized setup, the cell application was reversed, and the culture conditions were modified to preserve cellular polarization and integrity. These two parameters were crucial for the MDDCs....... In conclusion, we determined that AEC conditioning favoring cellular integrity leads to a tolerogenic MDDC phenotype, which is likely to be important in regulating immune responses against commonly inhaled allergens....

  2. Apical Gene Transfer into Quiescent Human and Canine Polarized Intestinal Epithelial Cells by Lentivirus Vectors

    OpenAIRE

    Seppen, Jurgen; Barry, Simon C.; Klinkspoor, J. Henriette; Katen, Louis J.; Lee, Sum P; Garcia, J. Victor; Osborne, William R. A.

    2000-01-01

    Intestinal epithelial cells secrete a protective luminal mucus barrier inhibiting viral gene transfer. Quiescent, polarized monolayers of primary epithelial cells from dog gallbladder and human colon are efficiently transduced through the apical mucus side by lentivirus vectors, suggesting their application to intestinal gene therapy.

  3. Evidence for Nuclear Tensor Polarization of Deuterium Molecules in Storage Cells

    International Nuclear Information System (INIS)

    Deuterium molecules were obtained by recombination, on a copper surface, of deuterium atoms prepared in specific hyperfine states. The molecules were stored for about 5ms in an open-ended cylindrical cell, placed in a 23mT magnetic field, and their tensor polarization was measured by elastic scattering of 704MeV electrons. The results of the measurements are consistent with the deuterium molecules retaining the tensor polarization of the initial atoms. copyright 1997 The American Physical Society

  4. Expression of Opacity Proteins Interferes with the Transmigration of Neisseria gonorrhoeae across Polarized Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Daniel C Stein

    Full Text Available Neisseria gonorrhoeae (GC establishes infection at the mucosal surface of the human genital tract, most of which is lined with polarized epithelial cells. GC can cause localized as well as disseminated infections, leading to various complications. GC constantly change their surface structures via phase and antigenic variation, which has been implicated as a means for GC to establish infection at various anatomic locations of male and female genital tracks. However, the exact contribution of each surface molecule to bacterial infectivity remains elusive due to their phase variation. Using a GC derivative that is genetically devoid of all opa genes (MS11∆Opa, this study shows that Opa expression interferes with GC transmigration across polarized human epithelial cells. MS11∆Opa transmigrates across polarized epithelial cells much faster and to a greater extent than MS11Opa+, while adhering at a similar level as MS11Opa+. When MS11Opa+, able to phase vary Opa expression, was inoculated, only those bacteria that turn off Opa expression transmigrate across the polarized epithelial monolayer. Similar to bacteria alone or co-cultured with non-polarized epithelial cells, MS11∆Opa fails to form large microcolonies at the apical surface of polarized epithelial cells. Apical inoculation of MS11Opa+, but not MS11∆Opa, induces the recruitment of the Opa host-cell receptor carcinoembryonic antigen-related cell adhesion molecules (CEACAMs to the apical junction and the vicinity of bacterial adherent sites. Our results suggest that Opa expression limits gonococcal ability to invade into subepithelial tissues by forming tight interactions with neighboring bacteria and by inducing CEACAM redistribution to cell junctions.

  5. Gastrointestinal cell lines form polarized epithelia with an adherent mucus layer when cultured in semi-wet interfaces with mechanical stimulation.

    Directory of Open Access Journals (Sweden)

    Nazanin Navabi

    Full Text Available Mucin glycoproteins are secreted in large quantities by mucosal epithelia and cell surface mucins are a prominent feature of the glycocalyx of all mucosal epithelia. Currently, studies investigating the gastrointestinal mucosal barrier use either animal experiments or non-in vivo like cell cultures. Many pathogens cause different pathology in mice compared to humans and the in vitro cell cultures used are suboptimal because they are very different from an in vivo mucosal surface, are often not polarized, lack important components of the glycocalyx, and often lack the mucus layer. Although gastrointestinal cell lines exist that produce mucins or polarize, human cell line models that reproducibly create the combination of a polarized epithelial cell layer, functional tight junctions and an adherent mucus layer have been missing until now. We trialed a range of treatments to induce polarization, 3D-organization, tight junctions, mucin production, mucus secretion, and formation of an adherent mucus layer that can be carried out using standard equipment. These treatments were tested on cell lines of intestinal (Caco-2, LS513, HT29, T84, LS174T, HT29 MTX-P8 and HT29 MTX-E12 and gastric (MKN7, MKN45, AGS, NCI-N87 and its hTERT Clone5 and Clone6 origins using Ussing chamber methodology and (immunohistology. Semi-wet interface culture in combination with mechanical stimulation and DAPT caused HT29 MTX-P8, HT29 MTX-E12 and LS513 cells to polarize, form functional tight junctions, a three-dimensional architecture resembling colonic crypts, and produce an adherent mucus layer. Caco-2 and T84 cells also polarized, formed functional tight junctions and produced a thin adherent mucus layer after this treatment, but with less consistency. In conclusion, culture methods affect cell lines differently, and testing a matrix of methods vs. cell lines may be important to develop better in vitro models. The methods developed herein create in vitro mucosal surfaces

  6. Iron repletion relocalizes hephaestin to a proximal basolateral compartment in polarized MDCK and Caco2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Min [Department of Biological Sciences, University of Columbia, NY (United States); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Attieh, Zouhair K. [Department of Laboratory Science and Technology, American University of Science and Technology, Ashrafieh (Lebanon); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Son, Hee Sook [Department of Food Science and Human Nutrition, College of Human Ecology, Chonbuk National University (Korea, Republic of); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Chen, Huijun [Medical School, Nanjing University, Nanjing 210008, Jiangsu Province (China); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Bacouri-Haidar, Mhenia [Department of Biology, Faculty of Sciences (I), Lebanese University, Hadath (Lebanon); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Vulpe, Chris D., E-mail: vulpe@berkeley.edu [Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States)

    2012-05-11

    Highlights: Black-Right-Pointing-Pointer Hephaestin localizes in the perinuclear space in non-polarized cells. Black-Right-Pointing-Pointer Hephaestin localizes in the perinuclear space in iron deficient and polarized cells. Black-Right-Pointing-Pointer Hephaestin with apical iron moves near to basolateral membrane of polarized cells. Black-Right-Pointing-Pointer Peri-basolateral location of hephaestin is accessible to the extracellular space. Black-Right-Pointing-Pointer Hephaestin is involved in iron mobilization from the intestine to circulation. -- Abstract: While intestinal cellular iron entry in vertebrates employs multiple routes including heme and non-heme routes, iron egress from these cells is exclusively channeled through the only known transporter, ferroportin. Reduced intestinal iron export in sex-linked anemia mice implicates hephaestin, a ferroxidase, in this process. Polarized cells are exposed to two distinct environments. Enterocytes contact the gut lumen via the apical surface of the cell, and through the basolateral surface, to the body. Previous studies indicate both local and systemic control of iron uptake. We hypothesized that differences in iron availability at the apical and/or basolateral surface may modulate iron uptake via cellular localization of hephaestin. We therefore characterized the localization of hephaestin in two models of polarized epithelial cell lines, MDCK and Caco2, with varying iron availability at the apical and basolateral surfaces. Our results indicate that hephaestin is expressed in a supra-nuclear compartment in non-polarized cells regardless of the iron status of the cells and in iron deficient and polarized cells. In polarized cells, we found that both apical (as FeSO{sub 4}) and basolateral iron (as the ratio of apo-transferrin to holo-transferrin) affect mobilization of hephaestin from the supra-nuclear compartment. We find that the presence of apical iron is essential for relocalization of hephaestin to a

  7. Reproducibility of 'Intelligent' Contouring of Gross Tumor Volume in Non-Small-Cell Lung Cancer on PET/CT Images Using a Standardized Visual Method

    International Nuclear Information System (INIS)

    Purpose: Positron emission tomography/computed tomography (PET/CT) is increasingly used for delineating gross tumor volume (GTV) in non-small-cell lung cancer (NSCLC). The methodology for contouring tumor margins remains controversial. We developed a rigorous visual protocol for contouring GTV that uses all available clinical information and studied its reproducibility in patients from a prospective PET/CT planning trial. Methods and Materials: Planning PET/CT scans from 6 consecutive patients were selected. Six 'observers' (two radiation oncologists, two nuclear medicine physicians, and two radiologists) contoured GTVs for each patient using a predefined protocol and subsequently recontoured 2 patients. For the estimated GTVs and axial distances, least-squares means for each observer and for each case were calculated and compared, using the F test and pairwise t-tests. In five cases, tumor margins were also autocontoured using standardized uptake value (SUV) cutoffs of 2.5 and 3.5 and 40% SUVmax. Results: The magnitude of variation between observers was small relative to the mean (coefficient of variation [CV] = 3%), and the total variation (intraclass correlation coefficient [ICC] = 3%). For estimation of superior/inferior (SI), left/right (LR), and anterior/posterior (AP) borders of the GTV, differences between observers were also small (AP, CV = 2%, ICC = 0.4%; LR, CV = 6%, ICC = 2%; SI, CV 4%, ICC = 2%). GTVs autocontoured generated using SUV 2.5, 3.5, and 40% SUVmax differed widely in each case. An SUV contour of 2.5 was most closely correlated with the mean GTV defined by the human observers. Conclusions: Observer variation contributed little to total variation in the GTV and axial distances. A visual contouring protocol gave reproducible results for contouring GTV in NSCLC.

  8. Kruppel-like factor 4 regulates intestinal epithelial cell morphology and polarity.

    Directory of Open Access Journals (Sweden)

    Tianxin Yu

    Full Text Available Krüppel-like factor 4 (KLF4 is a zinc finger transcription factor that plays a vital role in regulating cell lineage differentiation during development and maintaining epithelial homeostasis in the intestine. In normal intestine, KLF4 is predominantly expressed in the differentiated epithelial cells. It has been identified as a tumor suppressor in colorectal cancer. KLF4 knockout mice demonstrated a decrease in number of goblet cells in the colon, and conditional ablation of KLF4 from the intestinal epithelium led to altered epithelial homeostasis. However, the role of KLF4 in differentiated intestinal cells and colon cancer cells, as well as the mechanism by which it regulates homeostasis and represses tumorigenesis in the intestine is not well understood. In our study, KLF4 was partially depleted in the differentiated intestinal epithelial cells by a tamoxifen-inducible Cre recombinase. We found a significant increase in the number of goblet cells in the KLF4-deleted small intestine, suggesting that KLF4 is not only required for goblet cell differentiation, but also required for maintaining goblet cell numbers through its function in inhibiting cell proliferation. The number and position of Paneth cells also changed. This is consistent with the KLF4 knockout study using villin-Cre [1]. Through immunohistochemistry (IHC staining and statistical analysis, we found that a stem cell and/or tuft cell marker, DCAMKL1, and a proliferation marker, Ki67, are affected by KLF4 depletion, while an enteroendocrine cell marker, neurotensin (NT, was not affected. In addition, we found KLF4 depletion altered the morphology and polarity of the intestinal epithelial cells. Using a three-dimensional (3D intestinal epithelial cyst formation assay, we found that KLF4 is essential for cell polarity and crypt-cyst formation in human colon cancer cells. These findings suggest that, as a tumor suppressor in colorectal cancer, KLF4 affects intestinal epithelial cell

  9. Itinerant exosomes: emerging roles in cell and tissue polarity

    OpenAIRE

    Lakkaraju, Aparna; Rodriguez-Boulan, Enrique

    2008-01-01

    Cells use secreted signals (e.g. chemokines and growth factors) and sophisticated vehicles such as argosomes, cytonemes, tunneling nanotubes and exosomes to relay important information to other cells, often over large distances. Exosomes, 30–100-nm intraluminal vesicles of multivesicular bodies (MVB) released upon exocytic fusion of the MVB with the plasma membrane, are increasingly recognized as a novel mode of cell-independent communication. Exosomes have been shown to function in antigen p...

  10. Basolateral Invasion and Trafficking of Campylobacter jejuni in Polarized Epithelial Cells

    OpenAIRE

    Bouwman, L.I.; Niewold, P.; van Putten, J.P.M.

    2013-01-01

    Campylobacter jejuni is a major cause of bacterial diarrheal disease. Most enteropathogenic bacteria including C. jejuni can invade cultured eukaryotic cells via an actin- and/or microtubule-dependent and an energy-consuming uptake process. Recently, we identified a novel highly efficient C. jejuni invasion pathway that involves bacterial migration into the subcellular space of non-polarized epithelial cells (termed subvasion) followed by invasion from the cell basis. Here we report cellular ...

  11. Tumor cell-activated CARD9 signaling contributes to metastasis-associated macrophage polarization

    OpenAIRE

    Yang, M; Shao, J-H; Miao, Y-J; Cui, W.; Qi, Y-F; Han, J-H; Lin, X.; J. Du

    2014-01-01

    Macrophages are critical immune effector cells of the tumor microenvironment that promote seeding, extravasation and persistent growth of tumor cells in primary tumors and metastatic sites. Tumor progression and metastasis are affected by dynamic changes in the specific phenotypes of macrophage subpopulations; however, the mechanisms by which tumor cells modulate macrophage polarization remain incompletely understood. Caspase recruitment domain-containing protein 9 (CARD9) is a central adapto...

  12. Reproducibility of ultrasonic testing

    International Nuclear Information System (INIS)

    The reproducibility of amplitude quotations for both artificial and natural reflectors was studied for several combinations of instrument/search unit, all being of the same type. This study shows that in industrial inspection if a range of standardized equipment is used, a margin of error of about 6 decibels has to be taken into account (confidence interval of 95%). This margin is about 4 to 5 dB for natural or artificial defects located in the central area and about 6 to 7 dB for artificial defects located on the back surface. This lack of reproducibility seems to be attributable first to the search unit and then to the instrument and operator. These results were confirmed by analysis of calibration data obtained from 250 tests performed by 25 operators under shop conditions. The margin of error was higher than the 6 dB obtained in the study

  13. A Catalytic Role for Mod5 in the Formation of the Tea1 Cell Polarity Landmark

    OpenAIRE

    Bicho, Claudia C.; Kelly, David A.; Snaith, Hilary A.; Goryachev, Andrew B.; Sawin, Kenneth E.

    2010-01-01

    Summary Many systems regulating cell polarity involve stable landmarks defined by internal cues [1–5]. In the rod-shaped fission yeast Schizosaccharomyces pombe, microtubules regulate polarized vegetative growth via a landmark involving the protein Tea1 [6–9]. Tea1 is delivered to cell tips as packets of molecules associated with growing microtubule ends [10] and anchored at the plasma membrane via a mechanism involving interaction with the membrane protein Mod5 [11, 12]. Tea1 and Mod5 are hi...

  14. Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Masahiko; Nelson, Celeste M.; Myers, Connie A.; Bissell,Mina J.

    2006-09-29

    Maintenance of apico-basal polarity in normal breast epithelial acini requires a balance between cell proliferation, cell death, and proper cell-cell and cell-extracellular matrix signaling. Aberrations in any of these processes can disrupt tissue architecture and initiate tumor formation. Here we show that the small GTPase Rap1 is a crucial element in organizing acinar structure and inducing lumen formation. Rap1 activity in malignant HMT-3522 T4-2 cells is appreciably higher than in S1 cells, their non-malignant counterparts. Expression of dominant-negative Rap1 resulted in phenotypic reversion of T4-2 cells, led to formation of acinar structures with correct apico-basal polarity, and dramatically reduced tumor incidence despite the persistence of genomic abnormalities. The resulting acini contained prominent central lumina not observed when other reverting agents were used. Conversely, expression of dominant-active Rap1 in T4-2 cells inhibited phenotypic reversion and led to increased invasiveness and tumorigenicity. Thus, Rap1 acts as a central regulator of breast architecture, with normal levels of activation instructing apical polarity during acinar morphogenesis, and increased activation inducing tumor formation and progression to malignancy.

  15. Polarized THG microscopy identifies compositionally different lipid droplets in mammalian cells.

    Science.gov (United States)

    Bautista, Godofredo; Pfisterer, Simon G; Huttunen, Mikko J; Ranjan, Sanjeev; Kanerva, Kristiina; Ikonen, Elina; Kauranen, Martti

    2014-11-18

    Cells store excess lipids as two major compounds, triacylglycerols (TAGs) and cholesteryl esters (CEs), inside lipid droplets (LDs). The degree of lipid ordering is considered to play a major role in the mobility and enzymatic processing of lipids in LDs. Here, we provide evidence that polarized third-harmonic generation (THG) microscopy distinguishes between native TAG- and CE-enriched LDs in cells due to the different ordering of the two lipid species. We first demonstrate that the responses from synthetic TAG- and CE-enriched LDs using THG microscopy with linear and circular polarizations differ according to their different intrinsic ordering. We then employ simulations to dissect how polarization effects influence the THG from an isotropic LD. Finally, we induce TAG- and CE-enriched LDs in murine macrophages and demonstrate that polarized THG responses increase in a nonlinear fashion with increasing CE/TAG ratio. This suggests that with an increasing CE content, there is a rather sharp transition toward increased LD ordering. Our results demonstrate that polarized THG microscopy enables label-free quantitative analysis of LD ordering and discriminates between compositionally different LDs in intact mammalian cells. PMID:25418291

  16. Requirement for Dlgh-1 in planar cell polarity and skeletogenesis during vertebrate development.

    Directory of Open Access Journals (Sweden)

    Charlene Rivera

    Full Text Available The development of specialized organs is tightly linked to the regulation of cell growth, orientation, migration and adhesion during embryogenesis. In addition, the directed movements of cells and their orientation within the plane of a tissue, termed planar cell polarity (PCP, appear to be crucial for the proper formation of the body plan. In Drosophila embryogenesis, Discs large (dlg plays a critical role in apical-basal cell polarity, cell adhesion and cell proliferation. Craniofacial defects in mice carrying an insertional mutation in Dlgh-1 suggest that Dlgh-1 is required for vertebrate development. To determine what roles Dlgh-1 plays in vertebrate development, we generated mice carrying a null mutation in Dlgh-1. We found that deletion of Dlgh-1 caused open eyelids, open neural tube, and misorientation of cochlear hair cell stereociliary bundles, indicative of defects in planar cell polarity (PCP. Deletion of Dlgh-1 also caused skeletal defects throughout the embryo. These findings identify novel roles for Dlgh-1 in vertebrates that differ from its well-characterized roles in invertebrates and suggest that the Dlgh-1 null mouse may be a useful animal model to study certain human congenital birth defects.

  17. Polarization measurements on single-step co-fired solid oxide fuel cells (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Kyung Joong; Zink, Peter; Gopalan, Srikanth; Pal, Uday B. [Department of Manufacturing Engineering, Boston University, Boston, MA 02215 (United States)

    2007-10-11

    Anode-supported planar solid oxide fuel cells (SOFC) were successfully fabricated by a single step co-firing process. The cells comprised of a Ni + yttria-stabilized zirconia (YSZ) anode, a YSZ or scandia-stabilized zirconia (ScSZ) electrolyte, a (La{sub 0.85}Ca{sub 0.15}){sub 0.97}MnO{sub 3} (LCM) + YSZ cathode active layer, and an LCM cathode current collector layer. The fabrication process involved tape casting of the anode, screen printing of the electrolyte and the cathode, and single step co-firing of the green-state cells in the temperature range of 1300-1330 C for 2 h. Cells were tested in the temperature range of 700-800 C with humidified hydrogen as fuel and air as oxidant. Cell test results and polarization modeling showed that the polarization losses were dominated by the ohmic loss associated with the electrodes and the activation polarization of the cathode, and that the ohmic loss due to the ionic resistance of the electrolyte and the activation polarization of the anode were relatively insignificant. Ohmic resistance associated with the electrode was lowered by improving the electrical contact between the electrode and the current collector. Activation polarization of the cathode was reduced by the improvement of the microstructure of the cathode active layer and lowering the cell sintering temperature. The cell performance was further improved by increasing the porosity in the anode. As a result, the maximum power density of 1.5 W cm{sup -2} was achieved at 800 C with humidified hydrogen and air. (author)

  18. Multisite phosphorylation of the guanine nucleotide exchange factor Cdc24 during yeast cell polarization.

    Directory of Open Access Journals (Sweden)

    Stephanie C Wai

    Full Text Available BACKGROUND: Cell polarization is essential for processes such as cell migration and asymmetric cell division. A common regulator of cell polarization in most eukaryotic cells is the conserved Rho GTPase, Cdc42. In budding yeast, Cdc42 is activated by a single guanine nucleotide exchange factor, Cdc24. The mechanistic details of Cdc24 activation at the onset of yeast cell polarization are unclear. Previous studies have suggested an important role for phosphorylation of Cdc24, which may regulate activity or function of the protein, representing a key step in the symmetry breaking process. METHODOLOGY/PRINCIPAL FINDINGS: Here, we directly ask whether multisite phosphorylation of Cdc24 plays a role in its regulation. We identify through mass spectrometry analysis over thirty putative in vivo phosphorylation sites. We first focus on sites matching consensus sequences for cyclin-dependent and p21-activated kinases, two kinase families that have been previously shown to phosphorylate Cdc24. Through site-directed mutagenesis, yeast genetics, and light and fluorescence microscopy, we show that nonphosphorylatable mutations of these consensus sites do not lead to any detectable consequences on growth rate, morphology, kinetics of polarization, or localization of the mutant protein. We do, however, observe a change in the mobility shift of mutant Cdc24 proteins on SDS-PAGE, suggesting that we have indeed perturbed its phosphorylation. Finally, we show that mutation of all identified phosphorylation sites does not cause observable defects in growth rate or morphology. CONCLUSIONS/SIGNIFICANCE: We conclude that lack of phosphorylation on Cdc24 has no overt functional consequences in budding yeast. Yeast cell polarization may be more tightly regulated by inactivation of Cdc42 by GTPase activating proteins or by alternative methods of Cdc24 regulation, such as conformational changes or oligomerization.

  19. The Rho GTPase Cdc42 regulates hair cell planar polarity and cellular patterning in the developing cochlea

    Directory of Open Access Journals (Sweden)

    Anna Kirjavainen

    2015-03-01

    Full Text Available Hair cells of the organ of Corti (OC of the cochlea exhibit distinct planar polarity, both at the tissue and cellular level. Planar polarity at tissue level is manifested as uniform orientation of the hair cell stereociliary bundles. Hair cell intrinsic polarity is defined as structural hair bundle asymmetry; positioning of the kinocilium/basal body complex at the vertex of the V-shaped bundle. Consistent with strong apical polarity, the hair cell apex displays prominent actin and microtubule cytoskeletons. The Rho GTPase Cdc42 regulates cytoskeletal dynamics and polarization of various cell types, and, thus, serves as a candidate regulator of hair cell polarity. We have here induced Cdc42 inactivation in the late-embryonic OC. We show the role of Cdc42 in the establishment of planar polarity of hair cells and in cellular patterning. Abnormal planar polarity was displayed as disturbances in hair bundle orientation and morphology and in kinocilium/basal body positioning. These defects were accompanied by a disorganized cell-surface microtubule network. Atypical protein kinase C (aPKC, a putative Cdc42 effector, colocalized with Cdc42 at the hair cell apex, and aPKC expression was altered upon Cdc42 depletion. Our data suggest that Cdc42 together with aPKC is part of the machinery establishing hair cell planar polarity and that Cdc42 acts on polarity through the cell-surface microtubule network. The data also suggest that defects in apical polarization are influenced by disturbed cellular patterning in the OC. In addition, our data demonstrates that Cdc42 is required for stereociliogenesis in the immature cochlea.

  20. Reproducible research in palaeomagnetism

    Science.gov (United States)

    Lurcock, Pontus; Florindo, Fabio

    2015-04-01

    The reproducibility of research findings is attracting increasing attention across all scientific disciplines. In palaeomagnetism as elsewhere, computer-based analysis techniques are becoming more commonplace, complex, and diverse. Analyses can often be difficult to reproduce from scratch, both for the original researchers and for others seeking to build on the work. We present a palaeomagnetic plotting and analysis program designed to make reproducibility easier. Part of the problem is the divide between interactive and scripted (batch) analysis programs. An interactive desktop program with a graphical interface is a powerful tool for exploring data and iteratively refining analyses, but usually cannot operate without human interaction. This makes it impossible to re-run an analysis automatically, or to integrate it into a larger automated scientific workflow - for example, a script to generate figures and tables for a paper. In some cases the parameters of the analysis process itself are not saved explicitly, making it hard to repeat or improve the analysis even with human interaction. Conversely, non-interactive batch tools can be controlled by pre-written scripts and configuration files, allowing an analysis to be 'replayed' automatically from the raw data. However, this advantage comes at the expense of exploratory capability: iteratively improving an analysis entails a time-consuming cycle of editing scripts, running them, and viewing the output. Batch tools also tend to require more computer expertise from their users. PuffinPlot is a palaeomagnetic plotting and analysis program which aims to bridge this gap. First released in 2012, it offers both an interactive, user-friendly desktop interface and a batch scripting interface, both making use of the same core library of palaeomagnetic functions. We present new improvements to the program that help to integrate the interactive and batch approaches, allowing an analysis to be interactively explored and refined

  1. Magnetogastrography (MGG) Reproducibility Assessments

    Science.gov (United States)

    de la Roca-Chiapas, J. M.; Córdova, T.; Hernández, E.; Solorio, S.; Solís Ortiz, S.; Sosa, M.

    2006-09-01

    Seven healthy subjects underwent a magnetic pulse of 32 mT for 17 ms, seven times in 90 minutes. The procedure was repeated one and two weeks later. Assessments of the gastric emptying were carried out for each one of the measurements and a statistical analysis of ANOVA was performed for every group of data. The gastric emptying time was 19.22 ± 5 min. Reproducibility estimation was above 85%. Therefore, magnetogastrography seems to be an excellent technique to be implemented in routine clinical trials.

  2. Simple system for evaluating retardation of liquid crystal cells using grating type liquid crystal polarization splitters

    Science.gov (United States)

    Honma, Michinori; Nose, Toshiaki

    2016-04-01

    We propose a unique optical system for measuring the retardation of birefringent films using a pair of liquid crystal (LC) gratings; that is, the examined birefringent films are inserted between two LC gratings. Because the LC grating functions as a polarization beam splitter for circularly polarized light, the proposed system is optically equivalent to the measurement system using a pair of two circular polarizers. First, the polarization splitting performance of the LC grating is discussed. It is found that a sufficiently high voltage (such that the retardation is less than a half wavelength) has to be applied for the almost pure circularly polarized diffracted light. Next, the measurement of the retardation of a homogeneous LC cell as an examined birefringent film was demonstrated using the proposed method. The proposed method is revealed to have the same measurement performance as that of the conventional method using a pair of linear polarizers and has an advantage that there is no need for the optic axis of the test birefringent specimen to be set at a specific angle.

  3. Polarized exocyst-mediated vesicle fusion directs intracellular lumenogenesis within the C. elegans excretory cell.

    Science.gov (United States)

    Armenti, Stephen T; Chan, Emily; Nance, Jeremy

    2014-10-01

    Lumenogenesis of small seamless tubes occurs through intracellular membrane growth and directed vesicle fusion events. Within the Caenorhabditis elegans excretory cell, which forms seamless intracellular tubes (canals) that mediate osmoregulation, lumens grow in length and diameter when vesicles fuse with the expanding lumenal surface. Here, we show that lumenal vesicle fusion depends on the small GTPase RAL-1, which localizes to vesicles and acts through the exocyst vesicle-tethering complex. Loss of either the exocyst or RAL-1 prevents excretory canal lumen extension. Within the excretory canal and other polarized cells, the exocyst co-localizes with the PAR polarity proteins PAR-3, PAR-6 and PKC-3. Using early embryonic cells to determine the functional relationships between the exocyst and PAR proteins, we show that RAL-1 recruits the exocyst to the membrane, while PAR proteins concentrate membrane-localized exocyst proteins to a polarized domain. These findings reveal that RAL-1 and the exocyst direct the polarized vesicle fusion events required for intracellular lumenogenesis of the excretory cell, suggesting mechanistic similarities in the formation of topologically distinct multicellular and intracellular lumens. PMID:25102190

  4. Kv7.1 surface expression is regulated by epithelial cell polarization

    DEFF Research Database (Denmark)

    Andersen, Martin N; Olesen, Søren-Peter; Rasmussen, Hanne Borger

    2011-01-01

    deafness, and several mutations have been described as trafficking mutations. To learn more about the basic mechanisms that regulate K(V)7.1 surface expression, we have investigated the trafficking of K(V)7.1 during the polarization process of the epithelial cell line Madin-Darby Canine Kidney (MDCK) using...

  5. On temperature variations during 3He Polarization experiments in Pomeranchuk cells

    DEFF Research Database (Denmark)

    Geng, Q.; Rasmussen, Finn Berg

    1984-01-01

    Simple model calculations have been performed in relation to temperature changes in decompression experiments with Pomeranchuk cells, aiming at the production of spin polarized liquid **3He. Comparison with reported experiments indicates that thermal contact with the surroundings is too strong...

  6. Comparison study of distinguishing cancerous and normal prostate epithelial cells by confocal and polarization diffraction imaging.

    Science.gov (United States)

    Jiang, Wenhuan; Lu, Jun Qing; Yang, Li V; Sa, Yu; Feng, Yuanming; Ding, Junhua; Hu, Xin-Hua

    2016-07-01

    Accurate classification of malignant cells from benign ones can significantly enhance cancer diagnosis and prognosis by detection of circulating tumor cells (CTCs). We have investigated two approaches of quantitative morphology and polarization diffraction imaging on two prostate cell types to evaluate their feasibility as single-cell assay methods toward CTC detection after cell enrichment. The two cell types have been measured by a confocal imaging method to obtain their three-dimensional morphology parameters and by a polarization diffraction imaging flow cytometry (p-DIFC) method to obtain image texture parameters. The support vector machine algorithm was applied to examine the accuracy of cell classification with the morphology and diffraction image parameters. Despite larger mean values of cell and nuclear sizes of the cancerous prostate cells than the normal ones, it has been shown that the morphologic parameters cannot serve as effective classifiers. In contrast, accurate classification of the two prostate cell types can be achieved with high classification accuracies on measured data acquired separately in three measurements. These results provide strong evidence that the p-DIFC method has the potential to yield morphology-related “fingerprints” for accurate and label-free classification of the two prostate cell types. PMID:26616011

  7. Influenza H5N1 virus infection of polarized human alveolar epithelial cells and lung microvascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Yuen Kit M

    2009-10-01

    Full Text Available Abstract Background Highly pathogenic avian influenza (HPAI H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease. Aim To study influenza A (H5N1 virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease. Methods We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces. Results We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our

  8. Opening Reproducible Research

    Science.gov (United States)

    Nüst, Daniel; Konkol, Markus; Pebesma, Edzer; Kray, Christian; Klötgen, Stephanie; Schutzeichel, Marc; Lorenz, Jörg; Przibytzin, Holger; Kussmann, Dirk

    2016-04-01

    Open access is not only a form of publishing such that research papers become available to the large public free of charge, it also refers to a trend in science that the act of doing research becomes more open and transparent. When science transforms to open access we not only mean access to papers, research data being collected, or data being generated, but also access to the data used and the procedures carried out in the research paper. Increasingly, scientific results are generated by numerical manipulation of data that were already collected, and may involve simulation experiments that are completely carried out computationally. Reproducibility of research findings, the ability to repeat experimental procedures and confirm previously found results, is at the heart of the scientific method (Pebesma, Nüst and Bivand, 2012). As opposed to the collection of experimental data in labs or nature, computational experiments lend themselves very well for reproduction. Some of the reasons why scientists do not publish data and computational procedures that allow reproduction will be hard to change, e.g. privacy concerns in the data, fear for embarrassment or of losing a competitive advantage. Others reasons however involve technical aspects, and include the lack of standard procedures to publish such information and the lack of benefits after publishing them. We aim to resolve these two technical aspects. We propose a system that supports the evolution of scientific publications from static papers into dynamic, executable research documents. The DFG-funded experimental project Opening Reproducible Research (ORR) aims for the main aspects of open access, by improving the exchange of, by facilitating productive access to, and by simplifying reuse of research results that are published over the Internet. Central to the project is a new form for creating and providing research results, the executable research compendium (ERC), which not only enables third parties to

  9. Hybrid T-helper cells: stabilizing the moderate center in a polarized system.

    Directory of Open Access Journals (Sweden)

    Sui Huang

    Full Text Available Polarization of cell phenotypes, a common strategy to achieve cell type diversity in metazoa, results from binary cell-fate decisions in the branching pedigree of development. Such "either-or" fate decisions are controlled by two opposing cell fate-determining transcription factors. Each of the two distinct "master regulators" promotes differentiation of its respective sister lineage. But they also suppress one other, leading to their mutually exclusive expression in the two ensuing lineages. Thus, promiscuous coexistence of the antagonist regulators in the same cell, the hallmark of the common "undecided" progenitor of two sister lineages, is considered unstable. This antagonism ensures robust polarization into two discretely distinct cell types. But now the immune system's T-helper (Th cells and their two canonical subtypes, Th1 and Th2 cells, tell a different story, as revealed in three papers recently published in PLOS Biology. The intermediate state that co-expresses the two opposing master regulators of the Th1 and Th2 subtypes, T-bet and Gata3, is highly stable and is not necessarily an undecided precursor. Instead, the Th1/Th2 hybrid cell is a robust new type with properties of both Th1 and Th2 cells. These hybrid cells are functionally active and possess the benefit of moderation: self-limitation of effector T cell function to prevent excessive inflammation, a permanent risk in host defense that can cause tissue damage or autoimmunity. Gene regulatory network analysis suggests that stabilization of the intermediate center in a polarizing system can be achieved by minor tweaking of the architecture of the mutual suppression gene circuit, and thus is a design option readily available to evolution.

  10. Hybrid T-helper cells: stabilizing the moderate center in a polarized system.

    Science.gov (United States)

    Huang, Sui

    2013-01-01

    Polarization of cell phenotypes, a common strategy to achieve cell type diversity in metazoa, results from binary cell-fate decisions in the branching pedigree of development. Such "either-or" fate decisions are controlled by two opposing cell fate-determining transcription factors. Each of the two distinct "master regulators" promotes differentiation of its respective sister lineage. But they also suppress one other, leading to their mutually exclusive expression in the two ensuing lineages. Thus, promiscuous coexistence of the antagonist regulators in the same cell, the hallmark of the common "undecided" progenitor of two sister lineages, is considered unstable. This antagonism ensures robust polarization into two discretely distinct cell types. But now the immune system's T-helper (Th) cells and their two canonical subtypes, Th1 and Th2 cells, tell a different story, as revealed in three papers recently published in PLOS Biology. The intermediate state that co-expresses the two opposing master regulators of the Th1 and Th2 subtypes, T-bet and Gata3, is highly stable and is not necessarily an undecided precursor. Instead, the Th1/Th2 hybrid cell is a robust new type with properties of both Th1 and Th2 cells. These hybrid cells are functionally active and possess the benefit of moderation: self-limitation of effector T cell function to prevent excessive inflammation, a permanent risk in host defense that can cause tissue damage or autoimmunity. Gene regulatory network analysis suggests that stabilization of the intermediate center in a polarizing system can be achieved by minor tweaking of the architecture of the mutual suppression gene circuit, and thus is a design option readily available to evolution. PMID:23976879

  11. Can Ferroelectric Polarization Explain the High Performance of Hybrid Halide Perovskite Solar Cells?

    OpenAIRE

    Sherkar, Tejas; Koster, L Jan Anton

    2016-01-01

    The power conversion efficiency of photovoltaic cells based on the use of hybrid halide perovskites, CH3NH3PbX3 (X = Cl, Br, I), now exceeds 20%. Recently, it was suggested that this high performance originates from the presence of ferroelectricity in the perovskite, which is hypothesized to lower charge recombination in the device. Here, we investigate and quantify the influence of mesoscale ferroelectric polarization on the device performance of perovskite solar cells. We implement a 3D dri...

  12. Dchs1–Fat4 regulation of polarized cell behaviours during skeletal morphogenesis

    OpenAIRE

    Mao, Yaopan; Kuta, Anna; Crespo-Enriquez, Ivan; Whiting, Danielle; Martin, Tina; Mulvaney, Joanna; Irvine, Kenneth D.; Francis-West, Philippa

    2016-01-01

    Skeletal shape varies widely across species as adaptation to specialized modes of feeding and locomotion, but how skeletal shape is established is unknown. An example of extreme diversity in the shape of a skeletal structure can be seen in the sternum, which varies considerably across species. Here we show that the Dchs1-Fat4 planar cell polarity pathway controls cell orientation in the early skeletal condensation to define the shape and relative dimensions of the mouse sternum. These changes...

  13. Basolateral invasion and trafficking of Campylobacter jejuni in polarized epithelial cells.

    Directory of Open Access Journals (Sweden)

    Lieneke I Bouwman

    Full Text Available Campylobacter jejuni is a major cause of bacterial diarrheal disease. Most enteropathogenic bacteria including C. jejuni can invade cultured eukaryotic cells via an actin- and/or microtubule-dependent and an energy-consuming uptake process. Recently, we identified a novel highly efficient C. jejuni invasion pathway that involves bacterial migration into the subcellular space of non-polarized epithelial cells (termed subvasion followed by invasion from the cell basis. Here we report cellular requirements of this entry mechanism and the subsequent intracellular trafficking route of C. jejuni in polarized islands of Caco-2 intestinal epithelial cells. Advanced microscopy on infected cells revealed that C. jejuni invades the polarized intestinal cells via the subcellular invasion pathway. Remarkably, invasion was not blocked by the inhibitors of microtubule dynamics colchicine or paclitaxel, and was even enhanced after disruption of host cell actin filaments by cytochalasin D. Invasion also continued after dinitrophenol-induced cellular depletion of ATP, whereas this compound effectively inhibited the uptake of invasive Escherichia coli. Confocal microscopy demonstrated that intracellular C. jejuni resided in membrane-bound CD63-positive cellular compartments for up to 24 h. Establishment of a novel luciferase reporter-based bacterial viability assay, developed to overcome the limitations of the classical bacterial recovery assay, demonstrated that a subset of C. jejuni survived intracellularly for up to 48 h. Taken together, our results indicate that C. jejuni is able to actively invade polarized intestinal epithelial cells via a novel actin- and microtubule-independent mechanism and remains metabolically active in the intracellular niche for up to 48 hours.

  14. Planar cell polarity defects and defective Vangl2 trafficking in mutants for the COPII gene Sec24b

    NARCIS (Netherlands)

    Wansleeben, C.; Feitsma, H.; Montcouquiol, M.; Kroon, C.; Cuppen, E.; Meijlink, F.

    2010-01-01

    Among the cellular properties that are essential for the organization of tissues during animal development, the importance of cell polarity in the plane of epithelial sheets has become increasingly clear in the past decades. Planar cell polarity (PCP) signaling in vertebrates has indispensable roles

  15. Highly reproducible, efficient hysteresis-less CH3NH3PbI(3-x)Cl(x) planar hybrid solar cells without requiring heat-treatment.

    Science.gov (United States)

    Heo, Jin Hyuck; Im, Sang Hyuk

    2016-02-01

    CH3NH3PbI(3-x)Cl(x)(MAPbI(3-x)Cl(x)) mixed halide perovskite powder with uniform composition was synthesized via simple solution chemistry, which demonstrates highly reproducible, efficient planar type MAPbI(3-x)Cl(x) mixed halide perovskite solar cells. Pure MAPbI(3-x)Cl(x) mixed halide perovskite powder was synthesized by reacting a 3 : 1 molar ratio of MAI : PbCl2 powder mixture in isopropanol (IPA) solution for 30 min at 60 °C with subsequent repeated centrifugation and washing in IPA. IPA functions as both the reaction medium for the formation of MAPbI(3-x)Cl(x) mixed halide and a selective remover of unreacted MAI and MACl byproducts. Accordingly, we could deposit a pinhole-free dense MAPbI(3-x)Cl(x) mixed halide perovskite film on a TiO2/FTO substrate through a simple one step spin-coating of pure MAPbI(3-x)Cl(x) mixed halide perovskite powder in DMF solution with HI additive, without further long heat-treatment processes. The deposited MAPbI(3-x)Cl(x) mixed halide perovskite film revealed uniform composition throughout the entire area, and the ratio of Cl to I + Cl and I + Cl to Pb was constant at ∼0.03 and ∼1/3, respectively. On the other hand, the conventional MAPbI(3-x)Cl(x) mixed halide perovskite film prepared by the long heat-treatment process had non-uniform composition because the ratio of Cl to I + Cl fluctuated greatly from 0 to 7.2. The average efficiency of planar type MAPbI(3-x)Cl(x) mixed halide perovskite solar cells was 18.65% ± 0.30% and the champion cell had 1.11 V V(oc), 22.1 mA cm(-2) J(sc), 77% F.F., and 18.9% η for forward scan conditions and 1.11 V V(oc), 22.1 mA cm(-2) J(sc), 78% F.F., and 19.1% η for reverse scan conditions. Although the thickness of the MAPbI(3-x)Cl(x) mixed halide perovskite layer varied from ∼500 nm to ∼900 nm, the efficiency was within the range of 18.3%-19.0%. PMID:26781644

  16. Solid-State NMR on bacterial cells: selective cell wall signal enhancement and resolution improvement using dynamic nuclear polarization

    International Nuclear Information System (INIS)

    Dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance (NMR) has recently emerged as a powerful technique for the study of material surfaces. In this study, we demonstrate its potential to investigate cell surface in intact cells. Using Bacillus subtilis bacterial cells as an example, it is shown that the polarizing agent 1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol (TOTAPOL) has a strong binding affinity to cell wall polymers (peptidoglycan). This particular interaction is thoroughly investigated with a systematic study on extracted cell wall materials, disrupted cells, and entire cells, which proved that TOTAPOL is mainly accumulating in the cell wall. This property is used on one hand to selectively enhance or suppress cell wall signals by controlling radical concentrations and on the other hand to improve spectral resolution by means of a difference spectrum. Comparing DNP-enhanced and conventional solid-state NMR, an absolute sensitivity ratio of 24 was obtained on the entire cell sample. This important increase in sensitivity together with the possibility of enhancing specifically cell wall signals and improving resolution really opens new avenues for the use of DNP-enhanced solid-state NMR as an on-cell investigation tool. (authors)

  17. Polarized trafficking of the sorting receptor SorLA in neurons and MDCK cells.

    Science.gov (United States)

    Klinger, Stine C; Højland, Anne; Jain, Shweta; Kjolby, Mads; Madsen, Peder; Svendsen, Anna Dorst; Olivecrona, Gunilla; Bonifacino, Juan S; Nielsen, Morten S

    2016-07-01

    The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB, and Lipoprotein Lipase (LpL). Despite this, only the trafficking in nonpolarized cells has been described so far. Due to the many differences between polarized and nonpolarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We show that SorLA is mainly found in sorting endosomes and on the basolateral surface of MDCK cells and in the somatodendritic domain of neurons. This polarized distribution of SorLA respectively depends on an acidic cluster and an extended version of this cluster and involves the cellular adaptor complex AP-1. Furthermore, we show that SorLA can mediate transcytosis across a tight cell layer. PMID:27192064

  18. Participation of the cell polarity protein PALS1 to T-cell receptor-mediated NF-κB activation.

    Directory of Open Access Journals (Sweden)

    Gabrielle Carvalho

    Full Text Available BACKGROUND: Beside their established function in shaping cell architecture, some cell polarity proteins were proposed to participate to lymphocyte migration, homing, scanning, as well as activation following antigen receptor stimulation. Although PALS1 is a central component of the cell polarity network, its expression and function in lymphocytes remains unknown. Here we investigated whether PALS1 is present in T cells and whether it contributes to T Cell-Receptor (TCR-mediated activation. METHODOLOGY/PRINCIPAL FINDINGS: By combining RT-PCR and immunoblot assays, we found that PALS1 is constitutively expressed in human T lymphocytes as well as in Jurkat T cells. siRNA-based knockdown of PALS1 hampered TCR-induced activation and optimal proliferation of lymphocyte. We further provide evidence that PALS1 depletion selectively hindered TCR-driven activation of the transcription factor NF-κB. CONCLUSIONS: The cell polarity protein PALS1 is expressed in T lymphocytes and participates to the optimal activation of NF-κB following TCR stimulation.

  19. Reproducible Experiment Platform

    CERN Document Server

    Likhomanenko, Tatiana; Baranov, Alexander; Khairullin, Egor; Ustyuzhanin, Andrey

    2015-01-01

    Data analysis in fundamental sciences nowadays is an essential process that pushes frontiers of our knowledge and leads to new discoveries. At the same time we can see that complexity of those analyses increases fast due to a)~enormous volumes of datasets being analyzed, b)~variety of techniques and algorithms one have to check inside a single analysis, c)~distributed nature of research teams that requires special communication media for knowledge and information exchange between individual researchers. There is a lot of resemblance between techniques and problems arising in the areas of industrial information retrieval and particle physics. To address those problems we propose Reproducible Experiment Platform (REP), a software infrastructure to support collaborative ecosystem for computational science. It is a Python based solution for research teams that allows running computational experiments on shared datasets, obtaining repeatable results, and consistent comparisons of the obtained results. We present s...

  20. Reproducing in cities.

    Science.gov (United States)

    Mace, Ruth

    2008-02-01

    Reproducing in cities has always been costly, leading to lower fertility (that is, lower birth rates) in urban than in rural areas. Historically, although cities provided job opportunities, initially residents incurred the penalty of higher infant mortality, but as mortality rates fell at the end of the 19th century, European birth rates began to plummet. Fertility decline in Africa only started recently and has been dramatic in some cities. Here it is argued that both historical and evolutionary demographers are interpreting fertility declines across the globe in terms of the relative costs of child rearing, which increase to allow children to outcompete their peers. Now largely free from the fear of early death, postindustrial societies may create an environment that generates runaway parental investment, which will continue to drive fertility ever lower. PMID:18258904

  1. Constrained Nonlinear and Mixed Effects Differential Equation Models for Dynamic Cell Polarity Signaling

    OpenAIRE

    Xiao, Zhen; Brunel, Nicolas; Yang, Zhenbiao; Cui, Xinping

    2016-01-01

    The key of tip growth in eukaryotes is the polarized distribution on plasma membrane of a particle named ROP1. This distribution is the result of a positive feedback loop, whose mechanism can be described by a Differential Equation parametrized by two meaningful parameters kpf and knf . We introduce a mechanistic Integro-Differential Equation (IDE) derived from a spatiotemporal model of cell polarity and we show how this model can be fitted to real data, i.e., ROP1 intensities measured on pol...

  2. Highly reproducible, efficient hysteresis-less CH3NH3PbI3-xClx planar hybrid solar cells without requiring heat-treatment

    Science.gov (United States)

    Heo, Jin Hyuck; Im, Sang Hyuk

    2016-01-01

    CH3NH3PbI3-xClx(MAPbI3-xClx) mixed halide perovskite powder with uniform composition was synthesized via simple solution chemistry, which demonstrates highly reproducible, efficient planar type MAPbI3-xClx mixed halide perovskite solar cells. Pure MAPbI3-xClx mixed halide perovskite powder was synthesized by reacting a 3 : 1 molar ratio of MAI : PbCl2 powder mixture in isopropanol (IPA) solution for 30 min at 60 °C with subsequent repeated centrifugation and washing in IPA. IPA functions as both the reaction medium for the formation of MAPbI3-xClx mixed halide and a selective remover of unreacted MAI and MACl byproducts. Accordingly, we could deposit a pinhole-free dense MAPbI3-xClx mixed halide perovskite film on a TiO2/FTO substrate through a simple one step spin-coating of pure MAPbI3-xClx mixed halide perovskite powder in DMF solution with HI additive, without further long heat-treatment processes. The deposited MAPbI3-xClx mixed halide perovskite film revealed uniform composition throughout the entire area, and the ratio of Cl to I + Cl and I + Cl to Pb was constant at ~0.03 and ~1/3, respectively. On the other hand, the conventional MAPbI3-xClx mixed halide perovskite film prepared by the long heat-treatment process had non-uniform composition because the ratio of Cl to I + Cl fluctuated greatly from 0 to 7.2. The average efficiency of planar type MAPbI3-xClx mixed halide perovskite solar cells was 18.65% +/- 0.30% and the champion cell had 1.11 V Voc, 22.1 mA cm-2Jsc, 77% F.F., and 18.9% η for forward scan conditions and 1.11 V Voc, 22.1 mA cm-2Jsc, 78% F.F., and 19.1% η for reverse scan conditions. Although the thickness of the MAPbI3-xClx mixed halide perovskite layer varied from ~500 nm to ~900 nm, the efficiency was within the range of 18.3%-19.0%.CH3NH3PbI3-xClx(MAPbI3-xClx) mixed halide perovskite powder with uniform composition was synthesized via simple solution chemistry, which demonstrates highly reproducible, efficient planar type MAPbI3-x

  3. Planar cell polarity effector gene Intu regulates cell fate-specific differentiation of keratinocytes through the primary cilia

    OpenAIRE

    Dai, D.; Li, L.; Huebner, A; H. Zeng; Guevara, E; Claypool, D J; Liu, A.; Chen, J.

    2012-01-01

    Genes involved in the planar cell polarity (PCP) signaling pathway are essential for a number of developmental processes in mammals, such as convergent extension and ciliogenesis. Tissue-specific PCP effector genes of the PCP signaling pathway are believed to mediate PCP signals in a tissue- and cell type-specific manner. However, how PCP signaling controls the morphogenesis of mammalian tissues remains unclear. In this study, we investigated the role of inturned (Intu), a tissue-specific PCP...

  4. Trafficking through COPII stabilises cell polarity and drives secretion during Drosophila epidermal differentiation.

    Directory of Open Access Journals (Sweden)

    Michaela Norum

    Full Text Available BACKGROUND: The differentiation of an extracellular matrix (ECM at the apical side of epithelial cells implies massive polarised secretion and membrane trafficking. An epithelial cell is hence engaged in coordinating secretion and cell polarity for a correct and efficient ECM formation. PRINCIPAL FINDINGS: We are studying the molecular mechanisms that Drosophila tracheal and epidermal cells deploy to form their specific apical ECM during differentiation. In this work we demonstrate that the two genetically identified factors haunted and ghost are essential for polarity maintenance, membrane topology as well as for secretion of the tracheal luminal matrix and the cuticle. We show that they code for the Drosophila COPII vesicle-coating components Sec23 and Sec24, respectively, that organise vesicle transport from the ER to the Golgi apparatus. CONCLUSION: Taken together, epithelial differentiation during Drosophila embryogenesis is a concerted action of ECM formation, plasma membrane remodelling and maintenance of cell polarity that all three rely mainly, if not absolutely, on the canonical secretory pathway from the ER over the Golgi apparatus to the plasma membrane. Our results indicate that COPII vesicles constitute a central hub for these processes.

  5. Recording of polarization holograms in a liquid crystal cell with a photosensitive chalcogenide orientation layer [Invited].

    Science.gov (United States)

    Sheremet, Nina; Kurioz, Yuriy; Slyusarenko, Kostyantyn; Trunov, Michael; Reznikov, Yuriy

    2013-08-01

    Polarization gratings have been recorded in a combined liquid crystal (LC) cell made of a substrate covered with a photosensitive chalcogenide orientation layer and a reference substrate covered with a rubbed polyimide film. The gratings are formed due to the spatially modulated light-induced easy orientation axis on the chalcogenide surface recorded by two beams with opposite circular polarizations. The gratings are permanent, but they can be erased by one of the recording beams and re-recorded. The diffraction intensity of the circularly polarized light is achromatic and does not depend on the birefringence of the LC. The diffraction efficiency of the grating is of the order of a few percents. Application of an ac field causes a strong increase of the diffraction efficiency up to 45%. PMID:23913086

  6. Cell polarity and patterning by PIN trafficking through early endosomal compartments in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Hirokazu Tanaka

    2013-05-01

    Full Text Available PIN-FORMED (PIN proteins localize asymmetrically at the plasma membrane and mediate intercellular polar transport of the plant hormone auxin that is crucial for a multitude of developmental processes in plants. PIN localization is under extensive control by environmental or developmental cues, but mechanisms regulating PIN localization are not fully understood. Here we show that early endosomal components ARF GEF BEN1 and newly identified Sec1/Munc18 family protein BEN2 are involved in distinct steps of early endosomal trafficking. BEN1 and BEN2 are collectively required for polar PIN localization, for their dynamic repolarization, and consequently for auxin activity gradient formation and auxin-related developmental processes including embryonic patterning, organogenesis, and vasculature venation patterning. These results show that early endosomal trafficking is crucial for cell polarity and auxin-dependent regulation of plant architecture.

  7. Polarization of migrating monocytic cells is independent of PI 3-kinase activity.

    Directory of Open Access Journals (Sweden)

    Silvia Volpe

    Full Text Available BACKGROUND: Migration of mammalian cells is a complex cell type and environment specific process. Migrating hematopoietic cells assume a rapid amoeboid like movement when exposed to gradients of chemoattractants. The underlying signaling mechanisms remain controversial with respect to localization and distribution of chemotactic receptors within the plasma membrane and the role of PI 3-kinase activity in cell polarization. METHODOLOGY/PRINCIPAL FINDINGS: We present a novel model for the investigation of human leukocyte migration. Monocytic THP-1 cells transfected with the alpha(2A-adrenoceptor (alpha(2AAR display comparable signal transduction responses, such as calcium mobilization, MAP-kinase activation and chemotaxis, to the noradrenaline homologue UK 14'304 as when stimulated with CCL2, which binds to the endogenous chemokine receptor CCR2. Time-lapse video microscopy reveals that chemotactic receptors remain evenly distributed over the plasma membrane and that their internalization is not required for migration. Measurements of intramolecular fluorescence resonance energy transfer (FRET of alpha(2AAR-YFP/CFP suggest a uniform activation of the receptors over the entire plasma membrane. Nevertheless, PI 3-kinase activation is confined to the leading edge. When reverting the gradient of chemoattractant by moving the dispensing micropipette, polarized monocytes--in contrast to neutrophils--rapidly flip their polarization axis by developing a new leading edge at the previous posterior side. Flipping of the polarization axis is accompanied by re-localization of PI-3-kinase activity to the new leading edge. However, reversal of the polarization axis occurs in the absence of PI 3-kinase activation. CONCLUSIONS/SIGNIFICANCE: Accumulation and internalization of chemotactic receptors at the leading edge is dispensable for cell migration. Furthermore, uniformly distributed receptors allow the cells to rapidly reorient and adapt to changes in the

  8. MMP28 promotes macrophage polarization toward M2 cells and augments pulmonary fibrosis

    Science.gov (United States)

    Gharib, Sina A.; Johnston, Laura K.; Huizar, Isham; Birkland, Timothy P.; Hanson, Josiah; Wang, Ying; Parks, William C.; Manicone, Anne M.

    2014-01-01

    Members of the MMP family function in various processes of innate immunity, particularly in controlling important steps in leukocyte trafficking and activation. MMP28 (epilysin) is a member of this family of proteinases, and we have found that MMP28 is expressed by macrophages and regulates their recruitment to the lung. We hypothesized that MMP28 regulates other key macrophage responses, such as macrophage polarization. Furthermore, we hypothesized that these MMP28-dependent changes in macrophage polarization would alter fibrotic responses in the lung. We examined the gene expression changes in WT and Mmp28−/− BMDMs, stimulated with LPS or IL-4/IL-13 to promote M1 and M2 cells, respectively. We also collected macrophages from the lungs of Pseudomonas aeruginosa-exposed WT and Mmp28−/− mice to evaluate changes in macrophage polarization. Lastly, we evaluated the macrophage polarization phenotypes during bleomycin-induced pulmonary fibrosis in WT and Mmp28−/− mice and assessed mice for differences in weight loss and total collagen levels. We found that MMP28 dampens proinflammatory macrophage function and promots M2 programming. In both in vivo models, we found deficits in M2 polarization in Mmp28−/− mice. In bleomycin-induced lung injury, these changes were associated with reduced fibrosis. MMP28 is an important regulator of macrophage polarization, promoting M2 function. Loss of MMP28 results in reduced M2 polarization and protection from bleomycin-induced fibrosis. These findings highlight a novel role for MMP28 in macrophage biology and pulmonary disease. PMID:23964118

  9. Restoration of cell polarity and bile excretion function of hepatocytes in sandwich-culture

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-jie; WANG Ying; SUN Jia-bang; SONG Mao-min; QIAO Xin

    2007-01-01

    Objective:To investigate the nature of the restoration of cell polarity and bile excretion function in Sandwich-cultured hepatocytes.Methods:Freshly isolated hepatocytes from male Sprague-Dawley rats were cultured in a double layer collagen gel Sandwich configuration.Morphological changes were observed under a inverted microscope.The domain specific membrane associated protein DPP Ⅳ was tested by immunofluorescenee,and the bile excretion function was determined by using fluorescein diacetate.Hepatocytes cultured on a single layer of collagen gel were taken as control.Results:Adult rat hepatocytes cultured in a double layer collagen gel sandwich configuration regained its morphological and functional polarity and maintained polygonal morphology for at least 4 weeks.Immunofluorescence studies USing antibodies against DPP Ⅳ showed polarity restoration as early as 48 h.After cultured in the double layer collagen gel Sandwich configuration for 96 h the hepatocytes began to excrete bile;while hepatocytes cultured on a single layer collagen gel had no bile excretion.Conclusion:Hepatocytes cultured in a double layer collagen gel Sandwich configuration are able to regain their morphological and functional polarity givan certain conditions.Hepaotcyte culture is a useful tool for the study of polarity restoration.

  10. Mesenchymal stem cells alleviate experimental asthma by inducing polarization of alveolar macrophages.

    Science.gov (United States)

    Song, Xiaolian; Xie, Shuanshuan; Lu, Kun; Wang, Changhui

    2015-04-01

    The reparative and immunoregulatory properties of mesenchymal stromal cells (MSCs) have made them attractive candidates for cellular therapy. However, the underlying mechanism of the effects of transplanted MSCs on allergic asthma remains elusive. Here, we show that administration of MSCs isolated from human bone marrow provoked a pronounced polarization in alveolar macrophages to M2 subtypes, rather than induced an increase in the total macrophage number, and efficiently inhibited hallmark features of asthma, including airway hyperresponsiveness and eosinophilic accumulation. Moreover, transforming growth factor beta (TGF-β) signaling pathway appeared to mediate the effects of MSCs on macrophage polarization and subsequently the inhibition of hallmark features of asthma. Inhibition of TGF-β signaling was sufficient to inhibit the macrophage polarization in response to MSCs and consequently reserved the inhibitory effects of macrophage polarization on hallmark features of asthma. Collectively, our data demonstrate that human MSCs have immunosuppressive activity on asthma, which is mediated by TGF-β-signaling-dependent alveolar macrophage polarization. PMID:24958014

  11. Polarization independent beam fanning using a multi-domain liquid crystal cell.

    Science.gov (United States)

    Ren, Hongwen; Wu, Shin-Tson

    2009-07-01

    Polarization independent beam fanning using a multi-domain liquid crystal (LC) cell is demonstrated experimentally. In the neighboring domains, the LC directors are aligned in orthogonal directions. To prove concepts, two hybrid-aligned LC cells with four and six domains were fabricated. Applying a voltage across the LC layer will change the phase difference between the neighboring domains. When the phase difference is 2mpi (m is an integer), the LC cell will not disturb the incident beam. However, if the phase shift is (2m + 1)pi, the outgoing beam will fan out into several beams; the number of fanout beams is equal to the domain number. PMID:19582068

  12. Reproducible Experiment Platform

    Science.gov (United States)

    Likhomanenko, Tatiana; Rogozhnikov, Alex; Baranov, Alexander; Khairullin, Egor; Ustyuzhanin, Andrey

    2015-12-01

    Data analysis in fundamental sciences nowadays is an essential process that pushes frontiers of our knowledge and leads to new discoveries. At the same time we can see that complexity of those analyses increases fast due to a) enormous volumes of datasets being analyzed, b) variety of techniques and algorithms one have to check inside a single analysis, c) distributed nature of research teams that requires special communication media for knowledge and information exchange between individual researchers. There is a lot of resemblance between techniques and problems arising in the areas of industrial information retrieval and particle physics. To address those problems we propose Reproducible Experiment Platform (REP), a software infrastructure to support collaborative ecosystem for computational science. It is a Python based solution for research teams that allows running computational experiments on shared datasets, obtaining repeatable results, and consistent comparisons of the obtained results. We present some key features of REP based on case studies which include trigger optimization and physics analysis studies at the LHCb experiment.

  13. Trafficking of epidermal growth factor receptor ligands in polarized epithelial cells.

    Science.gov (United States)

    Singh, Bhuminder; Coffey, Robert J

    2014-01-01

    A largely unilamellar epithelial layer lines body cavities and organ ducts such as the digestive tract and kidney tubules. This polarized epithelium is composed of biochemically and functionally separate apical and basolateral surfaces. The epidermal growth factor receptor (EGFR) signaling pathway is a critical regulator of epithelial homeostasis and is perturbed in a number of epithelial disorders. It is underappreciated that in vivo EGFR signaling is most often initiated by cell-surface delivery and processing of one of seven transmembrane ligands, resulting in release of the soluble form that binds EGFR. In polarized epithelial cells, EGFR is restricted largely to the basolateral surface, and apical or basolateral ligand delivery therefore has important biological consequences. In vitro approaches have been used to study the biosynthesis, cell-surface delivery, proteolytic processing, and release of soluble EGFR ligands in polarized epithelial cells. We review these results, discuss their relevance to normal physiology, and demonstrate the pathophysiological consequences of aberrant trafficking. These studies have uncovered a rich diversity of apico-basolateral trafficking mechanisms among the EGFR ligands, provided insights into the pathogenesis of an inherited magnesium-wasting disorder of the kidney (isolated renal hypomagnesemia), and identified a new mode of EGFR ligand signaling via exosomes. PMID:24215440

  14. CAMSAP3 orients the apical-to-basal polarity of microtubule arrays in epithelial cells.

    Science.gov (United States)

    Toya, Mika; Kobayashi, Saeko; Kawasaki, Miwa; Shioi, Go; Kaneko, Mari; Ishiuchi, Takashi; Misaki, Kazuyo; Meng, Wenxiang; Takeichi, Masatoshi

    2016-01-12

    Polarized epithelial cells exhibit a characteristic array of microtubules that are oriented along the apicobasal axis of the cells. The minus-ends of these microtubules face apically, and the plus-ends face toward the basal side. The mechanisms underlying this epithelial-specific microtubule assembly remain unresolved, however. Here, using mouse intestinal cells and human Caco-2 cells, we show that the microtubule minus-end binding protein CAMSAP3 (calmodulin-regulated-spectrin-associated protein 3) plays a pivotal role in orienting the apical-to-basal polarity of microtubules in epithelial cells. In these cells, CAMSAP3 accumulated at the apical cortices, and tethered the longitudinal microtubules to these sites. Camsap3 mutation or depletion resulted in a random orientation of these microtubules; concomitantly, the stereotypic positioning of the nucleus and Golgi apparatus was perturbed. In contrast, the integrity of the plasma membrane was hardly affected, although its structural stability was decreased. Further analysis revealed that the CC1 domain of CAMSAP3 is crucial for its apical localization, and that forced mislocalization of CAMSAP3 disturbs the epithelial architecture. These findings demonstrate that apically localized CAMSAP3 determines the proper orientation of microtubules, and in turn that of organelles, in mature mammalian epithelial cells. PMID:26715742

  15. Within-person reproducibility of red blood cell mercury over a 10- to 15-year period among women in the Nurses' Health Study II

    DEFF Research Database (Denmark)

    Kioumourtzoglou, Marianthi-Anna; Roberts, Andrea L; Nielsen, Flemming;

    2016-01-01

    Most epidemiologic studies of methylmercury (MeHg) health effects rely on a single measurement of a MeHg biomarker to assess long-term exposures. Long-term reproducibility data are, therefore, needed to assess the reliability of a single measure to reflect long-term exposures. In this study, we a...

  16. A polarized gas internal target using a storage cell in an electron storage ring

    International Nuclear Information System (INIS)

    The first experiment using a storage cell to increase the thickness of an internal polarized gas target in an electron beam storage ring was performed at the VEPP-3 facility. We describe the storage cell technique as applied in this measurement of elastic and inelastic electron scattering from tensor polarized deuterium. An analysis of electron-beam-induced depolarization of the target was performed and experimental tests were carried out which verify the effect. Other effects causing depolarization of the target are discussed as well as the means by which they are overcome. The effective pzz of the target, shown to be stable over 8 months, was 0.57±0.05; the total target thickness was increased over that of a jet target by a factor of fifteen. (orig.)

  17. Polycystin-1 is a microtubule-driven desmosome-associated component in polarized epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Basora, Nuria, E-mail: Nuria.Basora@USherbrooke.ca [Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Quebec, Canada J1N 5N4 (Canada); Tetreault, Marie-Pier; Boucher, Marie-Pierre; Herring, Elizabeth; Beaulieu, Jean-Francois [Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Quebec, Canada J1N 5N4 (Canada)

    2010-05-15

    In this study, we have analyzed the expression and localization of polycystin-1 in intestinal epithelial cells, a system lacking primary cilia. Polycystin-1 was found to be expressed in the epithelium of the small intestine during development and levels remained elevated in the adult. Dual-labelling indirect immunofluorescence revealed polycystin-1 at sites of cell-cell contact co-localizing with the desmosomes both in situ as well as in polarized Caco-2/15 cells. In unpolarized cultures of Caco-2/15 cells, polycystin-1 was recruited to the cell surface early during initiation of cell junction assembly. In isolated Caco-2/15 cells and HIEC-6 cell cultures, where junctional complexes are absent, polycystin-1 was found predominantly associated with the cytoskeletal elements of the intermediate filaments and microtubule networks. More precisely, polycystin-1 was seen as brightly labelled puncta decorating the keratin-18 positive filaments as well as the {beta}-tubulin positive microtubules, which was particularly obvious in the lamellipodia. Treatment with the microtubule-disrupting agent, nocodazole, eliminated the microtubule association of polycystin-1 but did not seem to affect its association with keratin or the desmosomes. Taken together these data suggest that polycystin-1 is involved with the establishment of cell-cell junctions in absorptive intestinal epithelial cells and exploits the microtubule-based machinery in order to be transported to the plasma membrane.

  18. Polycystin-1 is a microtubule-driven desmosome-associated component in polarized epithelial cells

    International Nuclear Information System (INIS)

    In this study, we have analyzed the expression and localization of polycystin-1 in intestinal epithelial cells, a system lacking primary cilia. Polycystin-1 was found to be expressed in the epithelium of the small intestine during development and levels remained elevated in the adult. Dual-labelling indirect immunofluorescence revealed polycystin-1 at sites of cell-cell contact co-localizing with the desmosomes both in situ as well as in polarized Caco-2/15 cells. In unpolarized cultures of Caco-2/15 cells, polycystin-1 was recruited to the cell surface early during initiation of cell junction assembly. In isolated Caco-2/15 cells and HIEC-6 cell cultures, where junctional complexes are absent, polycystin-1 was found predominantly associated with the cytoskeletal elements of the intermediate filaments and microtubule networks. More precisely, polycystin-1 was seen as brightly labelled puncta decorating the keratin-18 positive filaments as well as the β-tubulin positive microtubules, which was particularly obvious in the lamellipodia. Treatment with the microtubule-disrupting agent, nocodazole, eliminated the microtubule association of polycystin-1 but did not seem to affect its association with keratin or the desmosomes. Taken together these data suggest that polycystin-1 is involved with the establishment of cell-cell junctions in absorptive intestinal epithelial cells and exploits the microtubule-based machinery in order to be transported to the plasma membrane.

  19. A glycophospholipid membrane anchor acts as an apical targeting signal in polarized epithelial cells

    OpenAIRE

    1989-01-01

    Glycosyl-phosphatidylinositol- (GPI) anchored proteins contain a large extracellular protein domain that is linked to the membrane via a glycosylated form of phosphatidylinositol. We recently reported the polarized apical distribution of all endogenous GPI-anchored proteins in the MDCK cell line (Lisanti, M. P., M. Sargiacomo, L. Graeve, A. R. Saltiel, and E. Rodriguez-Boulan. 1988. Proc. Natl. Acad. Sci. USA. 85:9557-9561). To study the role of this mechanism of membrane anchoring in targeti...

  20. Characterization of a pancreatic islet cell tumor in a polar bear (Ursus maritimus).

    Science.gov (United States)

    Fortin, Jessica S; Benoit-Biancamano, Marie-Odile

    2014-01-01

    Herein, we report a 25-year-old male polar bear suffering from a pancreatic islet cell tumor. The aim of this report is to present a case of this rare tumor in a captive polar bear. The implication of potential risk factors such as high carbohydrate diet or the presence of amyloid fibril deposits was assessed. Necropsy examination revealed several other changes, including nodules observed in the liver, spleen, pancreas, intestine, and thyroid glands that were submitted for histopathologic analysis. Interestingly, the multiple neoplastic nodules were unrelated and included a pancreatic islet cell tumor. Immunohistochemistry of the pancreas confirmed the presence of insulin and islet amyloid polypeptide (IAPP) within the pancreatic islet cells. The IAPP gene was extracted from the paraffin-embedded liver tissue and sequenced. IAPP cDNA from the polar bear exhibits some differences as compared to the sequence published for several other species. Different factors responsible for neoplasms in bears such as diet, infectious agents, and industrial chemical exposure are reviewed. This case report raised several issues that further studies may address by evaluating the prevalence of cancers in captive or wild animals. PMID:25273481

  1. Polarity of fatty acid uptake and metabolism in a human intestinal cell line (CACO-2)

    International Nuclear Information System (INIS)

    Free fatty acids (ffa) can enter the intestinal cell via the apical (AP) or basolateral (BL) membrane. The authors are using the Caco-2 intestinal cell line to examine the polarity of ffa uptake and metabolism in the enterocyte. Cells are grown on permeable polycarbonate Transwell filters in order to obtain access to both AP and BL compartments. Differentiated Caco-2 cells form tight polarized monolayers which express small intestine-specific enzymes and are impermeable to the fluid phase marker Lucifer Yellow. Submicellar concentrations of 3H-palmitic acid (2uM) were added to AP or BL sides of Caco-2 monolayers at 37 degrees C and cells were incubated for various times between 2 and 120 minutes. Total AP and BL uptake is similar; however, when relative membrane surface areas are accounted for, AP uptake is about 2-fold higher. The metabolism of AP and BL ffa is not significantly different: triacylglycerol and phosphatidylcholine account for most of the metabolites (32±4 and 24±2% respectively at 5 minutes). Little ffa oxidation is observed. Preincubation with albumin-bound 2-monoolein (100uM) and palmitate (50uM) increases the level of TG metabolites. The results suggest that in this cell line the uptake of AP ffa may be greater than BL ffa, but that AP (dietary) ffa and BL (plasma) ffa are metabolized similarly

  2. Polarity of fatty acid uptake and metabolism in a human intestinal cell line (CACO-2)

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, P.J.; Storch, J. (Harvard School of Public Health, Boston, MA (United States))

    1990-02-26

    Free fatty acids (ffa) can enter the intestinal cell via the apical (AP) or basolateral (BL) membrane. The authors are using the Caco-2 intestinal cell line to examine the polarity of ffa uptake and metabolism in the enterocyte. Cells are grown on permeable polycarbonate Transwell filters in order to obtain access to both AP and BL compartments. Differentiated Caco-2 cells form tight polarized monolayers which express small intestine-specific enzymes and are impermeable to the fluid phase marker Lucifer Yellow. Submicellar concentrations of {sup 3}H-palmitic acid (2uM) were added to AP or BL sides of Caco-2 monolayers at 37{degrees}C and cells were incubated for various times between 2 and 120 minutes. Total AP and BL uptake is similar; however, when relative membrane surface areas are accounted for, AP uptake is about 2-fold higher. The metabolism of AP and BL ffa is not significantly different: triacylglycerol and phosphatidylcholine account for most of the metabolites (32{plus minus}4 and 24{plus minus}2% respectively at 5 minutes). Little ffa oxidation is observed. Preincubation with albumin-bound 2-monoolein (100uM) and palmitate (50uM) increases the level of TG metabolites. The results suggest that in this cell line the uptake of AP ffa may be greater than BL ffa, but that AP (dietary) ffa and BL (plasma) ffa are metabolized similarly.

  3. Tumor cell-activated CARD9 signaling contributes to metastasis-associated macrophage polarization.

    Science.gov (United States)

    Yang, M; Shao, J-H; Miao, Y-J; Cui, W; Qi, Y-F; Han, J-H; Lin, X; Du, J

    2014-08-01

    Macrophages are critical immune effector cells of the tumor microenvironment that promote seeding, extravasation and persistent growth of tumor cells in primary tumors and metastatic sites. Tumor progression and metastasis are affected by dynamic changes in the specific phenotypes of macrophage subpopulations; however, the mechanisms by which tumor cells modulate macrophage polarization remain incompletely understood. Caspase recruitment domain-containing protein 9 (CARD9) is a central adaptor protein of innate immune responses to extracellular pathogens. We report that increased CARD9 expression is primarily localized in infiltrated macrophages and significantly associated with advanced histopathologic stage and the presence of metastasis. Using CARD9-deficient (CARD9(-/-)) mice, we show that bone marrow-derived CARD9 promotes liver metastasis of colon carcinoma cells. Mechanistic studies reveal that CARD9 contributes to tumor metastasis by promoting metastasis-associated macrophage polarization through activation of the nuclear factor-kappa B signaling pathway. We further demonstrate that tumor cell-secreted vascular endothelial growth factor facilitates spleen tyrosine kinase activation in macrophages, which is necessary for formation of the CARD9-B-cell lymphoma/leukemia 10-mucosa-associated lymphoid tissue lymphoma translocation protein 1 complex. Taken together, our results indicating that CARD9 is a regulator of metastasis-associated macrophages will lead to new insights into evolution of the microenvironments supporting tumor metastasis, thereby providing targets for anticancer therapies. PMID:24722209

  4. Co-regulation of cell polarization and migration by caveolar proteins PTRF/Cavin-1 and caveolin-1.

    Directory of Open Access Journals (Sweden)

    Michelle M Hill

    Full Text Available Caveolin-1 and caveolae are differentially polarized in migrating cells in various models, and caveolin-1 expression has been shown to quantitatively modulate cell migration. PTRF/cavin-1 is a cytoplasmic protein now established to be also necessary for caveola formation. Here we tested the effect of PTRF expression on cell migration. Using fluorescence imaging, quantitative proteomics, and cell migration assays we show that PTRF/cavin-1 modulates cellular polarization, and the subcellular localization of Rac1 and caveolin-1 in migrating cells as well as PKCα caveola recruitment. PTRF/cavin-1 quantitatively reduced cell migration, and induced mesenchymal epithelial reversion. Similar to caveolin-1, the polarization of PTRF/cavin-1 was dependent on the migration mode. By selectively manipulating PTRF/cavin-1 and caveolin-1 expression (and therefore caveola formation in multiple cell systems, we unveil caveola-independent functions for both proteins in cell migration.

  5. Optically-driven red blood cell rotor in linearly polarized laser tweezers

    Indian Academy of Sciences (India)

    Manas Khan; Samarendra K Mohanty; A K Sood

    2005-11-01

    We have constructed a dual trap optical tweezers set-up around an inverted microscope where both the traps can be independently controlled and manipulated in all the three dimensions. Here we report our observations on rotation of red blood cells (RBCs) in a linearly polarized optical trap. Red blood cells deform and become twisted in hypertonic phosphate buffer saline and when trapped, experience an unbalanced radiation pressure force. The torque generated from the unbalanced force causes the trapped RBC to rotate. Addition of Ca++ ions in the solution, keeping the osmolarity same, makes the cell membranes stiffer and the cells deform less. Thus the speed of rotation of the red blood cells can be controlled, as less deformation and in turn less asymmetry in shape produces less torque under the radiation pressure resulting in slower rotation at the same laser power.

  6. Non-invasive imaging of cellulose microfibril orientation within plant cell walls by polarized Raman microspectroscopy.

    Science.gov (United States)

    Sun, Lan; Singh, Seema; Joo, Michael; Vega-Sanchez, Miguel; Ronald, Pamela; Simmons, Blake A; Adams, Paul; Auer, Manfred

    2016-01-01

    Cellulose microfibrils represent the major scaffold of plant cell walls. Different packing and orientation of the microfibrils at the microscopic scale determines the macroscopic properties of cell walls and thus affect their functions with a profound effect on plant survival. We developed a polarized Raman microspectroscopic method to determine cellulose microfibril orientation within rice plant cell walls. Employing an array of point measurements as well as area imaging and subsequent Matlab-assisted data processing, we were able to characterize the distribution of cellulose microfibril orientation in terms of director angle and anisotropy magnitude. Using this approach we detected differences between wild type rice plants and the rice brittle culm mutant, which shows a more disordered cellulose microfibril arrangement, and differences between different tissues of a wild type rice plant. This novel non-invasive Raman imaging approach allows for quantitative assessment of cellulose fiber orientation in cell walls of herbaceous plants, an important advancement in cell wall characterization. PMID:26137889

  7. Chimera proteins with affinity for membranes and microtubule tips polarize in the membrane of fission yeast cells.

    Science.gov (United States)

    Recouvreux, Pierre; Sokolowski, Thomas R; Grammoustianou, Aristea; Ten Wolde, Pieter Rein; Dogterom, Marileen

    2016-02-16

    Cell polarity refers to a functional spatial organization of proteins that is crucial for the control of essential cellular processes such as growth and division. To establish polarity, cells rely on elaborate regulation networks that control the distribution of proteins at the cell membrane. In fission yeast cells, a microtubule-dependent network has been identified that polarizes the distribution of signaling proteins that restricts growth to cell ends and targets the cytokinetic machinery to the middle of the cell. Although many molecular components have been shown to play a role in this network, it remains unknown which molecular functionalities are minimally required to establish a polarized protein distribution in this system. Here we show that a membrane-binding protein fragment, which distributes homogeneously in wild-type fission yeast cells, can be made to concentrate at cell ends by attaching it to a cytoplasmic microtubule end-binding protein. This concentration results in a polarized pattern of chimera proteins with a spatial extension that is very reminiscent of natural polarity patterns in fission yeast. However, chimera levels fluctuate in response to microtubule dynamics, and disruption of microtubules leads to disappearance of the pattern. Numerical simulations confirm that the combined functionality of membrane anchoring and microtubule tip affinity is in principle sufficient to create polarized patterns. Our chimera protein may thus represent a simple molecular functionality that is able to polarize the membrane, onto which additional layers of molecular complexity may be built to provide the temporal robustness that is typical of natural polarity patterns. PMID:26831106

  8. Effect of toxic components on microbial fuel cell-polarization curves and estimation of the type of toxic inhibition

    NARCIS (Netherlands)

    Stein, N.E.; Hamelers, H.V.M.; Straten, G. van; Keesman, K.J.

    2012-01-01

    Polarization curves are of paramount importance for the detection of toxic components in microbial fuel cell (MFC) based biosensors. In this study, polarization curves were made under non-toxic conditions and under toxic conditions after the addition of various concentrations of nickel, bentazon, so

  9. NKp46 clusters at the immune synapse and regulates NK cell polarization

    Directory of Open Access Journals (Sweden)

    Uzi eHadad

    2015-09-01

    Full Text Available Natural killer cells play an important role in first-line defense against tumor and virus-infected cells. The activity of NK cells is tightly regulated by a repertoire of cell-surface expressed inhibitory and activating receptors. NKp46 is a major NK cell activating receptor that is involved in the elimination of target cells. NK cells form different types of synapses that result in distinct functional outcomes: cytotoxic, inhibitory, and regulatory. Recent studies revealed that complex integration of NK receptor signaling controls cytoskeletal rearrangement and other immune synapse-related events. However the distinct nature by which NKp46 participates in NK immunological synapse formation and function remains unknown. In this study we determined that NKp46 forms microclusters structures at the immune synapse between NK cells and target cells. Over-expression of human NKp46 is correlated with increased accumulation of F-actin mesh at the immune synapse. Concordantly, knock-down of NKp46 in primary human NK cells decreased recruitment of F-actin to the synapse. Live cell imaging experiments showed a linear correlation between NKp46 expression and lytic granules polarization to the immune synapse. Taken together, our data suggest that NKp46 signaling directly regulates the NK lytic immune synapse from early formation to late function.

  10. Hand1-Luc embryonic stem cell test (Hand1-Luc EST): a novel rapid and highly reproducible in vitro test for embryotoxicity by measuring cytotoxicity and differentiation toxicity using engineered mouse ES cells.

    Science.gov (United States)

    Le Coz, Florian; Suzuki, Noriyuki; Nagahori, Hirohisa; Omori, Takashi; Saito, Koichi

    2015-04-01

    The embryonic stem cell test (EST) is a promising alternative method for evaluating embryotoxicity of test chemicals by measuring cytotoxicity and differentiation toxicity using mouse ES cells. Differentiation toxicity is analyzed by microscopically counting the beating of embryonic bodies after 10 days of culture. However, improvements are necessary to reduce the laborious manipulations involved and the time required to obtain results. We have previously reported the successful stable transfection of ES cells (ES-D3) with the heart and neural crest derivatives expressed transcript 1 (Hand1) gene and the establishment of a 96-well multi-plate-based new EST with luciferase reporter assay 6 days after treatment with test chemicals. Now, we propose an even more rapid and easier EST, named Hand1-Luc EST. We established another cell line to monitor the Hand1 gene expression via a luciferase reporter gene. By mRNA analysis and luciferase assay, we examined in detail the luciferase activity during cell differentiation, which allowed us to reduce the time of measurement from day 6 to day 5 (120 hr). Furthermore, the protocol was improved, with, among others, the measurement of cytotoxicity and differentiation toxicity taking place in the same 96-well round bottom plate instead of two different plates. With the positive control, 5-fluorouracil (5-FU), and 9 test chemicals, data with high reproducibility and very low variation (CV short-term test for prediction of embryotoxicants by measuring cytotoxicity and differentiation toxicity from the same sample. PMID:25786529

  11. In vivo determination of fibril orientation in plant cell walls with polarization CSLM

    International Nuclear Information System (INIS)

    Congo Red fluorescence is used to detect cellulose in the wall of plant cells. The orientation of the cellulose fibrils is determined by using polarized light for excitation. The absorption characteristics of Congo Red make this approach a method of choice for applications with any standard confocal scanning laser microscope (CSLM). The semiquantitative character of CSLM observations combined with the non-toxicity of the stain allow a very fast and reliable assessment of cellulose orientation in the wall of living plant cells. (author)

  12. A noninvasive transfer system for polarized renal tubule epithelial cell sheets using temperature-responsive culture dishes

    Directory of Open Access Journals (Sweden)

    Kushida A.

    2005-08-01

    Full Text Available We used temperature-responsive culture dishes onto which the temperature-responsive polymer, poly(Nisopropylacrylamide, was covalently grafted for tissue engineering. Confluent cells harvested as intact sheets from these surfaces by simple temperature reduction can be transferred to various surfaces including additional culture dishes, other cell sheets, and tissues. In order to examine the maintenance of cell polarity, Madin-Darby canine kidney cells and human primary renal proximal tubule epithelial cells which had developed apical-basal cell polarity in culture, were subjected to cell sheet transfer. This functional and structural cell polarity, which is susceptible to treatment with trypsin, was examined by immunohistochemistry and transmission electron microscopy. Using our cell-sheet method, the noninvasive transfer of these cell sheets retaining typical distributions of Na+/K+-ATPase, GLUT-1, SGLT-1, aquaporin-1, neutral endopeptidase and dipeptidylendopeptidase IV, could be achieved. The transferred cell sheets also developed numerous microvilli and tight junctions at the apical and lateral membranes, respectively. For biochemical analysis, immunoblotting of occludin, a transmembrane protein that composes tight junctions, was conducted and results confirmed that occludin remained intact after cell sheet transfer. This two-dimensional cell sheet manipulation method promises to be useful for tissue engineering as well as in the investigation of epithelial cell polarity.

  13. Intertissue mechanical stress affects Frizzled-mediated planar cell polarity in the Drosophila notum epidermis.

    Science.gov (United States)

    Olguín, Patricio; Glavic, Alvaro; Mlodzik, Marek

    2011-02-01

    Frizzled/planar cell polarity (Fz/PCP) signaling controls the orientation of sensory bristles and cellular hairs (trichomes) along the anteroposterior axis of the Drosophila thorax (notum). A subset of the trichome-producing notum cells differentiate as "tendon cells," serving as attachment sites for the indirect flight muscles (IFMs) to the exoskeleton. Through the analysis of chascon (chas), a gene identified by its ability to disrupt Fz/PCP signaling under overexpression conditions, and jitterbug (jbug)/filamin, we show that maintenance of anteroposterior planar polarization requires the notum epithelia to balance mechanical stress generated by the attachment of the IFMs. chas is expressed in notum tendon cells, and its loss of function disturbs cellular orientation at and near the regions where IFMs attach to the epidermis. This effect is independent of the Fz/PCP and fat/dachsous systems. The chas phenotype arises during normal shortening of the IFMs and is suppressed by genetic ablation of the IFMs. chas acts through jbug/filamin and cooperates with MyosinII to modulate the mechanoresponse of notum tendon cells. These observations support the notion that the ability of epithelia to respond to mechanical stress generated by one or more interactions with other tissues during development and organogenesis influences the maintenance of its shape and PCP features. PMID:21276726

  14. Mycobacterium tuberculosislpdC, Rv0462, induces dendritic cell maturation and Th1 polarization

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Deok Rim [Department of Microbiology and Immunology, School of Medicine, Pusan National University, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of); Shin, Sung Jae; Kim, Woo Sik [Department of Microbiology, College of Medicine, Chungnam National University, Munwha-Dong, Jung-Ku, Daejeon 301-747 (Korea, Republic of); Noh, Kyung Tae; Park, Jin Wook; Son, Kwang Hee [Department of Microbiology and Immunology, School of Medicine, Pusan National University, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of); Park, Won Sun [Department of Physiology, Kangwon National University, School of Medicine, Chuncheon 200-701 (Korea, Republic of); Lee, Min-Goo [Department of Physiology, Korea University, College of Medicine, Anam-dong, Sungbuk-Gu, Seoul 136-705 (Korea, Republic of); Kim, Daejin [Department of Anatomy, Chung-Ang University, College of Medicine, 221 Heuksuk-Dong, Dongjak-Ku, Seoul 156-756 (Korea, Republic of); Shin, Yong Kyoo [Department of Pharmacology, Chung-Ang University, College of Medicine, 221 Heuksuk-Dong, Dongjak-Ku, Seoul 156-756 (Korea, Republic of); Jung, In Duk, E-mail: jungid@pusan.ac.kr [Department of Microbiology and Immunology, School of Medicine, Pusan National University, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of); Research Institute of Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of); Park, Yeong-Min, E-mail: immunpym@pusan.ac.kr [Department of Microbiology and Immunology, School of Medicine, Pusan National University, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of); Research Institute of Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Beom-eo Ri, Mulgum Eop, Yangsan, Gyeongsangnam-do 626-770 (Korea, Republic of)

    2011-08-05

    Highlights: {yields} Treatment with Rv0462 induces the expression of surface molecules and the production of cytokines in DCs. {yields} Rv0462 induces the activation of MAPKs. {yields} Rv0462-treated DCs enhances the proliferation of CD4{sup +} T cells. -- Abstract: Mycobacterium tuberculosis, the etiological factor of pulmonary tuberculosis, causes significant morbidity and mortality worldwide. Activation of host immune responses for containment of mycobacterial infections involves participation of innate immune cells, such as dendritic cells (DCs). In this study, we demonstrated that the gene encoding lipoamide dehydrogenase C (lpdC) from M. tuberculosis, Rv0462, induce maturation and activation of DCs involved in the MAPKs signaling pathway. Moreover, Rv0462-treated DCs activated naive T cells, polarized CD4{sup +} and CD8{sup +} T cells to secrete IFN-{gamma} in syngeneic mixed lymphocyte reactions, which would be expected to contribute to Th1 polarization of the immune response. Our results suggest that Rv0462 can contribute to the innate and adaptive immune responses during tuberculosis infection, and thus modulate the clinical course of tuberculosis.

  15. Dystroglycan loss disrupts polarity and beta-casein induction inmammary epithelial cells by perturbing laminin anchoring

    Energy Technology Data Exchange (ETDEWEB)

    Weir, M. Lynn; Oppizzi, Maria Luisa; Henry, Michael D.; Onishi,Akiko; Campbell, Kevin P.; Bissell, Mina J.; Muschler, John L.

    2006-02-17

    Precise contact between epithelial cells and their underlying basement membrane is critical to the maintenance of tissue architecture and function. To understand the role that the laminin receptor dystroglycan (DG) plays in these processes, we assayed cell responses to laminin-111 following conditional ablation of DG expression in cultured mammary epithelial cells (MECs). Strikingly, DG loss disrupted laminin-111-induced polarity and {beta}-casein production, and abolished laminin assembly at the step of laminin binding to the cell surface. DG re-expression restored these deficiencies. Investigations of mechanism revealed that DG cytoplasmic sequences were not necessary for laminin assembly and signaling, and only when the entire mucin domain of extracellular DG was deleted did laminin assembly not occur. These results demonstrate that DG is essential as a laminin-111 co-receptor in MECs that functions by mediating laminin anchoring to the cell surface, a process that allows laminin polymerization, tissue polarity, and {beta}-casein induction. The observed loss of laminin-111 assembly and signaling in DG-/-MECs provides insights into the signaling changes occurring in breast carcinomas and other cancers, where DG's laminin-binding function is frequently defective.

  16. T cell receptor reversed polarity recognition of a self-antigen major histocompatibility complex.

    Science.gov (United States)

    Beringer, Dennis X; Kleijwegt, Fleur S; Wiede, Florian; van der Slik, Arno R; Loh, Khai Lee; Petersen, Jan; Dudek, Nadine L; Duinkerken, Gaby; Laban, Sandra; Joosten, Antoinette; Vivian, Julian P; Chen, Zhenjun; Uldrich, Adam P; Godfrey, Dale I; McCluskey, James; Price, David A; Radford, Kristen J; Purcell, Anthony W; Nikolic, Tatjana; Reid, Hugh H; Tiganis, Tony; Roep, Bart O; Rossjohn, Jamie

    2015-11-01

    Central to adaptive immunity is the interaction between the αβ T cell receptor (TCR) and peptide presented by the major histocompatibility complex (MHC) molecule. Presumably reflecting TCR-MHC bias and T cell signaling constraints, the TCR universally adopts a canonical polarity atop the MHC. We report the structures of two TCRs, derived from human induced T regulatory (iT(reg)) cells, complexed to an MHC class II molecule presenting a proinsulin-derived peptide. The ternary complexes revealed a 180° polarity reversal compared to all other TCR-peptide-MHC complex structures. Namely, the iT(reg) TCR α-chain and β-chain are overlaid with the α-chain and β-chain of MHC class II, respectively. Nevertheless, this TCR interaction elicited a peptide-reactive, MHC-restricted T cell signal. Thus TCRs are not 'hardwired' to interact with MHC molecules in a stereotypic manner to elicit a T cell signal, a finding that fundamentally challenges our understanding of TCR recognition. PMID:26437244

  17. Mycobacterium tuberculosislpdC, Rv0462, induces dendritic cell maturation and Th1 polarization

    International Nuclear Information System (INIS)

    Highlights: → Treatment with Rv0462 induces the expression of surface molecules and the production of cytokines in DCs. → Rv0462 induces the activation of MAPKs. → Rv0462-treated DCs enhances the proliferation of CD4+ T cells. -- Abstract: Mycobacterium tuberculosis, the etiological factor of pulmonary tuberculosis, causes significant morbidity and mortality worldwide. Activation of host immune responses for containment of mycobacterial infections involves participation of innate immune cells, such as dendritic cells (DCs). In this study, we demonstrated that the gene encoding lipoamide dehydrogenase C (lpdC) from M. tuberculosis, Rv0462, induce maturation and activation of DCs involved in the MAPKs signaling pathway. Moreover, Rv0462-treated DCs activated naive T cells, polarized CD4+ and CD8+ T cells to secrete IFN-γ in syngeneic mixed lymphocyte reactions, which would be expected to contribute to Th1 polarization of the immune response. Our results suggest that Rv0462 can contribute to the innate and adaptive immune responses during tuberculosis infection, and thus modulate the clinical course of tuberculosis.

  18. [Targeting of type IV carbonic anhydrases in Capan-1 human pancreatic duct cells is concomitant of the polarization].

    Science.gov (United States)

    Mairal, A; Fanjul, M; Hollande, E

    1996-01-01

    Carbonic anhydrases II and IV play an essential role in the synthesis and secretion of HCO3- ions in pancreatic duct cells. Secretion of these ions is regulated by the CFTR (cystic fibrosis transmembrane conductance regulator) chloride channel. In the present study, the expression of carbonic anhydrases IV and their targeting to plasma membranes were examined during the growth of human pancreatic duct cells in vitro. Human cancerous pancreatic duct cells of Capan-1 cell line which polarize during their growth were used. We show that: a) these cells express carbonic anhydrases IV continuously during growth in culture, and the expression depends on the stage of growth and the conformation of the cells; b) carbonic anhydrases IV are seen in the cytoplasm in non-polarized cells, but become progressively anchored to plasma membranes as the cells polarize, being targeted to the apical membranes of polarized cells; c) the subcellular distribution of carbonic anhydrases IV indicates that these enzymes are synthetized in rough endoplasmic reticulum and then transported towards the plasma membrane using the classical secretory pathway through the Golgi apparatus. The results indicated that targeting of carbonic anhydrases IV in Capan-1 cells is linked to cellular polarization. PMID:8881572

  19. Bone cell-material interactions on metal-ion doped polarized hydroxyapatite

    International Nuclear Information System (INIS)

    The objective of this work is to study the influence of Mg2+ and Sr2+ dopants on in vitro bone cell-material interactions of electrically polarized hydroxyapatite [HAp, Ca10(PO4)6(OH)2] ceramics with an aim to achieve additional advantage of matching bone chemistry along with the original benefits of electrical polarization treatment relevant to biomedical applications. To achieve our research objective, commercial phase pure HAp has been doped with MgO, and SrO in single, and binary compositions. All samples have been sintered at 1200 deg. C for 2 h and subsequently polarized using an external d.c. field (2.0 kV/cm) at 400 deg. C for 1 h. Combined addition of 1 wt.% MgO/1 wt.% SrO in HAp has been most beneficial in enhancing the polarizability in which stored charge was 4.19 μC/cm2 compared to pure HAp of 2.23 μC/cm2. Bone cell-material interaction has been studied by culturing with human fetal osteoblast cells (hFOB) for a maximum of 7 days. Scanning electron microscope (SEM) images of cell morphology reveal that favorable surface properties and dopant chemistry lead to good cellular adherence and spreading on negatively charged surfaces of both Sr2+ and Mg2+ doped HAp samples over undoped HAp. MTT assay results at 7 days show the highest viable cell densities on the negatively charged surfaces of binary doped HAp samples, while positive charged doped HAp surfaces exhibit limited cellular growth in comparison to neutral surfaces.

  20. Comparison of clinical grade type 1 polarized and standard matured dendritic cells for cancer immunotherapy

    DEFF Research Database (Denmark)

    Hansen, Morten; Hjortø, Gertrud Malene; Donia, Marco;

    2013-01-01

    induction of type 1 effector T cells. Standard matured clinical grade DCs “sDCs” were compared with DCs matured with either of two type 1 polarizing maturation cocktails; the alpha-type-1 DCs “αDC1s” (TNF-α, IL-1β, IFN-γ, IFN-α, Poly(I:C)) and “mDCs” (monophosphoryl lipid A (MPL), IFN-γ) or a mixed cocktail...... – “mpDCs”, containing MPL, IFN-γ and PGE2. αDC1s and mDCs secreted IL-12 directly and following re-stimulation with CD40L-expressing cells and they mainly secreted the T effector cell attracting chemokines CXCL10 and CCL5 as opposed to sDCs that mainly secreted CCL22, known to attract regulatory T cells...

  1. Cancer-associated fibroblasts as another polarized cell type of the tumor microenvironment

    Directory of Open Access Journals (Sweden)

    MartinAugsten

    2014-03-01

    Full Text Available Tumor- or cancer-associated fibroblasts (CAFs are one of the most abundant stromal cell types in different carcinomas and comprise a heterogeneous cell population. Classically, CAFs are assigned with pro-tumorigenic effects stimulating tumor growth and progression. More recent studies demonstrated also tumor-inhibitory effects of CAFs suggesting that tumor-residing fibroblasts exhibit a similar degree of plasticity as other stromal cell types. Reciprocal interactions with the tumor milieu and different sources of origin are emerging as two important factors underlying CAF heterogeneity. This review highlights recent advances in our understanding of CAF biology and proposes to expand the term of cellular ´polarization´, previously introduced to describe different activation states of various immune cells, onto CAFs to reflect their phenotypic diversity.

  2. Coupling of cytoplasm and adhesion dynamics determines cell polarization and locomotion

    CERN Document Server

    Bock, Martin; Möhl, Christoph

    2009-01-01

    Observations of single epidermal cells on flat adhesive substrates have revealed two distinct morphological and functional states, namely a non-migrating symmetric unpolarized state and a migrating asymmetric polarized state. These states are characterized by different spatial distributions and dynamics of important biochemical cell components: F-actin and myosin-II form the contractile part of the cytoskeleton, and integrin receptors in the plasma membrane connect F-actin filaments to the substratum. In this way, focal adhesion complexes are assembled, which determine cytoskeletal force transduction and subsequent cell locomotion. So far, physical models have reduced this phenomenon either to gradients in regulatory control molecules or to different mechanics of the actin filament system in different regions of the cell. Here we offer an alternative and self-organizational model incorporating polymerization, pushing and sliding of filaments, as well as formation of adhesion sites and their force dependent ki...

  3. Expression and subcellular localization of aquaporin water channels in the polarized hepatocyte cell line, WIF-B

    OpenAIRE

    Marinelli Raúl A; Splinter Patrick L; Tietz Pamela S; Gradilone Sergio A; LaRusso Nicholas F

    2005-01-01

    Abstract Background Recent data suggest that canalicular bile secretion involves selective expression and coordinated regulation of aquaporins (AQPs), a family of water channels proteins. In order to further characterize the role of AQPs in this process, an in vitro cell system with retained polarity and expression of AQPs and relevant solute transporters involved in bile formation is highly desirable. The WIF-B cell line is a highly differentiated and polarized rat hepatoma/human fibroblast ...

  4. The blood-brain barrier induces differentiation of migrating monocytes into Th17-polarizing dendritic cells.

    Science.gov (United States)

    Ifergan, Igal; Kébir, Hania; Bernard, Monique; Wosik, Karolina; Dodelet-Devillers, Aurore; Cayrol, Romain; Arbour, Nathalie; Prat, Alexandre

    2008-03-01

    Trafficking of antigen-presenting cells into the CNS is essential for lymphocyte reactivation within the CNS compartment. Although perivascular dendritic cells found in inflammatory lesions are reported to polarize naive CD4+ T lymphocytes into interleukin-17-secreting-cells, the origin of those antigen-presenting cells remains controversial. We demonstrate that a subset of CD14+ monocytes migrate across the inflamed human blood-brain barrier (BBB) and differentiate into CD83+CD209+ dendritic cells under the influence of BBB-secreted transforming growth factor-beta and granulocyte-macrophage colony-stimulating factor. We also demonstrate that these dendritic cells secrete interleukin-12p70, transforming growth factor-beta and interleukin-6 and promote the proliferation and expansion of distinct populations of interferon-gamma-secreting Th1 and interleukin-17-secreting Th17 CD4+ T lymphocytes. We further confirmed the abundance of such dendritic cells in situ, closely associated with microvascular BBB-endothelial cells within acute multiple sclerosis lesions, as well as a significant number of CD4+ interleukin-17+ T lymphocytes in the perivascular infiltrate. Our data support the notion that functional perivascular myeloid CNS dendritic cells arise as a consequence of migration of CD14+ monocytes across the human BBB, through the concerted actions of BBB-secreted transforming growth factor-beta and granulocyte-macrophage colony-stimulating factor. PMID:18156156

  5. Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5ee03874j Click here for additional data file.

    Science.gov (United States)

    Matsui, Taisuke; Seo, Ji-Youn; Domanski, Konrad; Correa-Baena, Juan-Pablo; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik M.; Tress, Wolfgang; Abate, Antonio; Hagfeldt, Anders; Grätzel, Michael

    2016-01-01

    Today's best perovskite solar cells use a mixture of formamidinium and methylammonium as the monovalent cations. With the addition of inorganic cesium, the resulting triple cation perovskite compositions are thermally more stable, contain less phase impurities and are less sensitive to processing conditions. This enables more reproducible device performances to reach a stabilized power output of 21.1% and ∼18% after 250 hours under operational conditions. These properties are key for the industrialization of perovskite photovoltaics.

  6. Highly polarized Th17 cells induce EAE via a T-bet-independent mechanism

    Science.gov (United States)

    Grifka-Walk, Heather M.; Lalor, Stephen J.; Segal, Benjamin M.

    2013-01-01

    Summary In the MOG35-55 induced EAE model, autoreactive Th17 cells that accumulate in the central nervous system (CNS) acquire Th1 characteristics via a T-bet dependent mechanism. It remains to be determined whether Th17 plasticity and encephalitogenicity are causally related to each other. Here we show that IL-23 polarized Tbet−/− Th17 cells are unimpaired in either activation or proliferation, and induce higher quantities of the chemokines RANTES and CXCL2 than wildtype (WT) Th17 cells. Unlike their WT counterparts, they retain an IL-17hiIFNγneg-lo cytokine profile following adoptive transfer into syngeneic hosts. This population of highly polarized Th17 effectors is capable of mediating EAE, albeit with a milder clinical course. It has previously been reported that the signature Th1 and Th17 effector cytokines, IFNγ and IL-17, are dispensable for the development of autoimmune demyelinating disease. The current study demonstrates that the “master regulator” transcription factor, T-bet, is also not universally required for encephalitogenicity. Our results contribute to a growing body of data showing heterogeneity of myelin-reactive T cells and the independent mechanisms they employ to inflict damage to CNS tissues, complicating the search for therapeutic targets relevant across the spectrum of individuals with multiple sclerosis. PMID:23878008

  7. Atypical Cadherin Fat1 Is Required for Lens Epithelial Cell Polarity and Proliferation but Not for Fiber Differentiation

    OpenAIRE

    Sugiyama, Yuki; Shelley, Elizabeth J.; Badouel, Caroline; McNeill, Helen; McAvoy, John W.

    2015-01-01

    Using knockout mice, we show that atypical cadherin Fat1 is essential for lens epithelial cells to maintain cell junctions, polarity, and proliferation but not for terminal fiber cell differentiation. We also report that Fat4 does not exhibit functional redundancy with Fat1 during lens development.

  8. New circular polarization selective surface concepts based on the Pierrot cell using printed circuit technology

    Science.gov (United States)

    Lopez, Humberto Israel

    This M.A.Sc. thesis focuses on finding an alternative method of constructing a circular polarization selective surface (CPSS) based on the Pierrot cell using the standard printed circuit technology. This technique uses a folded flexible substrate, which enables the implementation of the 3D Pierrot cells on a single metal layer defined with precision printed circuit board techniques, without the need for metalized via holes. Different topologies of the CPSS are analyzed in order to make the CPSS more efficient in terms of bandwidth and independence on the direction of propagation of the incident wave. A left-hand CPSS is designed to illustrate the benefits of the proposed approach. The first approach is a simple Pierrot unit cell CPSS which is optimized to have good reflection and transmission coefficients. A prototype is built and then characterized in a test bench operating in the K-band. For the fabricated prototype, the transmission coefficients of plane waves at normal incidence in the right-hand and the left-hand circular polarizations are --0.48 dB and --24 dB respectively. The bandwidth for which the transmission coefficient of the incident left-handed incident wave is greater than --3 dB was of 17.6%. These results are in good agreement with simulations results obtained with HFSS. A second variant considered is a Pierrot cell with a series load in the middle segment. With this cell it is possible to equalize the frequencies giving a better operation in the right- and left-handed circular polarized waves. There is an improvement for the co-pol to cross-pol ratio for the RHCP waves of 10 dB at 20 GHz. The added load does not affect the performance for the left-hand circular polarization, as expected. The third modification is a Pierrot cell at 90 degrees. This cell is designed to allow the combination of two Pierrot cells working at different frequencies on the same substrate in order to increase the frequency bandwidth of the CPSS. Unfortunately, the axial

  9. Influence of polar solvents on photovoltaic performance of Monascusred dye-sensitized solar cell

    Science.gov (United States)

    Lee, Jae Wook; Kim, Tae Young; Ko, Hyun Seok; Han, Shin; Lee, Suk-Ho; Park, Kyung Hee

    Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from Monascus red pigment as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in Monascus red DSSC using different solvents. The effect of polar aprotic and protic solvents including water, ethanol, and dimethylsulfoxide (DMSO) used in the sensitization process was investigated for the improvement in conversion efficiency of a cell. As for the Monascus red dye-sensitized electrode in DMSO solvent, the solar cell yields a short-circuit current density (Jsc) of 1.23 mA/cm2, a photovoltage (Voc) of 0.75 V, and a fill factor of 0.72, corresponding to an energy conversion efficiency (η) of 0.66%.

  10. Polarization of calcium signaling and fluid secretion in salivary gland cells.

    Science.gov (United States)

    Ambudkar, I S

    2012-01-01

    The secretion of fluid, electrolytes, and protein by exocrine gland acinar cells is a vectorial process that requires the coordinated regulation of multiple channel and transporter proteins, signaling components, as well as mechanisms involved in vesicular fusion and water transport. Most critical in this is the regulation of cytosolic free [Ca(2+)] ([Ca(2+)](i)) in response to neurotransmitter stimulation. Control of [Ca(2+)](i) increase in specific regions of the cell is the main determinant of fluid and electrolyte secretion in salivary gland acinar cells as it regulates several major ion flux mechanisms as well as the water channel that are required for this process. Polarized [Ca(2+)](i) signals are also essential for protein secretion in pancreatic acinar cells. Thus, the mechanisms that generate and modulate these compartmentalized [Ca(2+)](i) signals are central to the regulation of exocrine secretion. These mechanisms include membrane receptors for neurotransmitters, intracellular Ca(2+) release channels, Ca(2+) entry channels, as well Ca(2+) as pumps and mitochondria. The spatial arrangement of proteins involved in Ca(2+) signaling is of primary significance in the generation of specific compartmentalized [Ca(2+)](i) signals. Within these domains, both local and global [Ca(2+)](i) changes are tightly controlled. Control of secretion is also dependent on the targeting of ion channels and transporters to specific domains in the cell where their regulation by [Ca(2+)](i) signals is facilitated. Together, the polarized localization of Ca(2+) signaling and secretory components drive vectorial secretion of fluid, electrolytes, and proteins in the exocrine salivary glands and pancreas. This review will discuss recent findings which have led to resolution of the molecular components underlying the spatio-temporal control of [Ca(2+)](i) signals in exocrine gland cells and their role in secretion. PMID:23061636

  11. Dishevelled is essential for neural connectivity and planar cell polarity in planarians.

    Science.gov (United States)

    Almuedo-Castillo, Maria; Saló, Emili; Adell, Teresa

    2011-02-15

    The Wingless/Integrated (Wnt) signaling pathway controls multiple events during development and homeostasis. It comprises multiple branches, mainly classified according to their dependence on β-catenin activation. The Wnt/β-catenin branch is essential for the establishment of the embryonic anteroposterior (AP) body axis throughout the phylogenetic tree. It is also required for AP axis establishment during planarian regeneration. Wnt/β-catenin-independent signaling encompasses several different pathways, of which the most extensively studied is the planar cell polarity (PCP) pathway, which is responsible for planar polarization of cell structures within an epithelial sheet. Dishevelled (Dvl) is the hub of Wnt signaling because it regulates and channels the Wnt signal into every branch. Here, we analyze the role of Schmidtea mediterranea Dvl homologs (Smed-dvl-1 and Smed-dvl-2) using gene silencing. We demonstrate that in addition to a role in AP axis specification, planarian Dvls are involved in at least two different β-catenin-independent processes. First, they are essential for neural connectivity through Smed-wnt5 signaling. Second, Smed-dvl-2, together with the S. mediterranea homologs of Van-Gogh (Vang) and Diversin (Div), is required for apical positioning of the basal bodies of epithelial cells. These data represent evidence not only of the function of the PCP network in lophotrocozoans but of the involvement of the PCP core elements Vang and Div in apical positioning of the cilia. PMID:21282632

  12. Planar Cell Polarity Protein Localization in the Secretory Ameloblasts of Rat Incisors

    OpenAIRE

    Nishikawa, Sumio; Kawamoto, Tadafumi

    2012-01-01

    The localization of the planar cell polarity proteins Vang12, frizzled-3, Vang11, and Celsr1 in the rat incisors was examined using immunocytochemistry. The results showed that Vang12 was localized at two regions of the Tomes’ processes of inner enamel–secretory ameloblasts in rat incisors: a proximal and a distal region. In contrast, frizzled-3 was localized at adherens junctions of the proximal and distal areas of inner enamel– and outer enamel–secretory ameloblasts, where N-cadherin and β-...

  13. Sensitivity and reproducibility of urinary C-peptide as estimate of islet B-cell function in insulin-treated diabetes

    DEFF Research Database (Denmark)

    Gjessing, H J; Matzen, L E; Faber, O K;

    1989-01-01

    The aims of the present study were to evaluate the ability of urinary C-peptide determination to demonstrate presence of residual insulin secretion, and to evaluate the reproducibility of urinary C-peptide excretion in 125 insulin-treated diabetic patients. C-peptide was determined in two...... limit, 49 of 125 patients were without residual insulin secretion. In contrast to this, only 7 patients were diagnosed as C-peptide nonsecretors using the analytical detection limit of urinary C-peptide. Eighty-four per cent of patients considered to have Type 1 (insulin-dependent) diabetes with a...... consecutive 24-h urine specimens and related to plasma C-peptide 6 min after the intravenous injection of 1 mg glucagon. The detection limit of C-peptide in plasma was defined analytically (greater than or equal to 0.02 nmol l-1) and from pancreatectomized patients (greater than or equal to 0.06 nmol l-1...

  14. Exine dehiscing induces rape microspore polarity, which results in different daughter cell fate and fixes the apical–basal axis of the embryo

    Science.gov (United States)

    Tang, Xingchun; Liu, Yuan; Sun, Meng-xiang

    2013-01-01

    The roles of cell polarity and the first asymmetric cell division during early embryogenesis in apical–basal cell fate determination remain unclear. Previously, a novel Brassica napus microspore embryogenesis system was established, by which rape exine-dehisced microspores were induced by physical stress. Unlike traditional microspore culture, cell polarity and subsequent asymmetric division appeared in the exine-dehisced microspore, which finally developed into a typical embryo with a suspensor. Further studies indicated that polarity is critical for apical–basal cell fate determination and suspensor formation. However, the pattern of the first division was not only determined by cell polarity but was also regulated by the position of the ruptured exine. The first division could be equal or unequal, with its orientation essentially perpendicular to the polar axis. In both types of cell division, the two daughter cells could have different cell fates and give rise to an embryo with a suspensor, similar to zygotic apical–basal cell differentiation. The alignment of the two daughter cells is consistent with the orientation of the apical–basal axis of future embryonic development. Thus, the results revealed that exine dehiscing induces rape microspore polarization, and this polarity results in a different cell fate and fixes the apical–basal axis of embryogenesis, but is uncoupled from cell asymmetric division. The present study demonstrated the relationships among cell polarity, asymmetric cell division, and cell fate determination in early embryogenesis. PMID:23162119

  15. Exine dehiscing induces rape microspore polarity, which results in different daughter cell fate and fixes the apical-basal axis of the embryo.

    Science.gov (United States)

    Tang, Xingchun; Liu, Yuan; He, Yuqing; Ma, Ligang; Sun, Meng-Xiang

    2013-01-01

    The roles of cell polarity and the first asymmetric cell division during early embryogenesis in apical-basal cell fate determination remain unclear. Previously, a novel Brassica napus microspore embryogenesis system was established, by which rape exine-dehisced microspores were induced by physical stress. Unlike traditional microspore culture, cell polarity and subsequent asymmetric division appeared in the exine-dehisced microspore, which finally developed into a typical embryo with a suspensor. Further studies indicated that polarity is critical for apical-basal cell fate determination and suspensor formation. However, the pattern of the first division was not only determined by cell polarity but was also regulated by the position of the ruptured exine. The first division could be equal or unequal, with its orientation essentially perpendicular to the polar axis. In both types of cell division, the two daughter cells could have different cell fates and give rise to an embryo with a suspensor, similar to zygotic apical-basal cell differentiation. The alignment of the two daughter cells is consistent with the orientation of the apical-basal axis of future embryonic development. Thus, the results revealed that exine dehiscing induces rape microspore polarization, and this polarity results in a different cell fate and fixes the apical-basal axis of embryogenesis, but is uncoupled from cell asymmetric division. The present study demonstrated the relationships among cell polarity, asymmetric cell division, and cell fate determination in early embryogenesis. PMID:23162119

  16. Poldip2 controls vascular smooth muscle cell migration by regulating focal adhesion turnover and force polarization

    Science.gov (United States)

    Datla, Srinivasa Raju; McGrail, Daniel J.; Vukelic, Sasa; Huff, Lauren P.; Lyle, Alicia N.; Pounkova, Lily; Lee, Minyoung; Seidel-Rogol, Bonnie; Khalil, Mazen K.; Hilenski, Lula L.; Terada, Lance S.; Dawson, Michelle R.; Lassègue, Bernard

    2014-01-01

    Polymerase-δ-interacting protein 2 (Poldip2) interacts with NADPH oxidase 4 (Nox4) and regulates migration; however, the precise underlying mechanisms are unclear. Here, we investigated the role of Poldip2 in focal adhesion turnover, as well as traction force generation and polarization. Poldip2 overexpression (AdPoldip2) in vascular smooth muscle cells (VSMCs) impairs PDGF-induced migration and induces a characteristic phenotype of long cytoplasmic extensions. AdPoldip2 also prevents the decrease in spreading and increased aspect ratio observed in response to PDGF and slightly impairs cell contraction. Moreover, AdPoldip2 blocks focal adhesion dissolution and sustains H2O2 levels in focal adhesions, whereas Poldip2 knockdown (siPoldip2) significantly decreases the number of focal adhesions. RhoA activity is unchanged when focal adhesion dissolution is stimulated in control cells but increases in AdPoldip2-treated cells. Inhibition of RhoA blocks Poldip2-mediated attenuation of focal adhesion dissolution, and overexpression of RhoA or focal adhesion kinase (FAK) reverses the loss of focal adhesions induced by siPoldip2, indicating that RhoA and FAK mediate the effect of Poldip2 on focal adhesions. Nox4 silencing prevents focal adhesion stabilization by AdPoldip2 and induces a phenotype similar to siPoldip2, suggesting a role for Nox4 in Poldip2-induced focal adhesion stability. As a consequence of impaired focal adhesion turnover, PDGF-treated AdPoldip2 cells are unable to reduce and polarize traction forces, a necessary first step in migration. These results implicate Poldip2 in VSMC migration via regulation of focal adhesion turnover and traction force generation in a Nox4/RhoA/FAK-dependent manner. PMID:25063792

  17. Normal and tumor-derived myoepithelial cells differ in their ability to interact with luminal breast epithelial cells for polarity and basement membrane deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gudjonsson, Thorarinn; Ronnov-Jessen, Lone; Villadsen, Rene; Rank, Fritz; Bissell, Mina J.; Petersen, Ole William

    2001-10-04

    The signals that determine the correct polarity of breast epithelial structures in vivo are not understood. We have shown previously that luminal epithelial cells can be polarized when cultured within a reconstituted basement membrane gel. We reasoned that such cues in vivo may be given by myoepithelial cells. Accordingly, we used an assay where luminal epithelial cells are incorrectly polarized to test this hypothesis. We show that culturing human primary luminal epithelial cells within collagen-I gels leads to formation of structures with no lumina and with reverse polarity as judged by dual stainings for sialomucin, epithelial specific antigen or occludin. No basement membrane is deposited, and {beta}4-integrin staining is negative. Addition of purified human myoepithelial cells isolated from normal glands corrects the inverse polarity, and leads to formation of double-layered acini with central lumina. Among the laminins present in the human breast basement membrane (laminin-1, -5 and -10/11), laminin-1 was unique in its ability to substitute for myoepithelial cells in polarity reversal. Myoepithelial cells were purified also from four different breast cancer sources including a biphasic cell line. Three out of four samples either totally lacked the ability to interact with luminal epithelial cells, or conveyed only correction of polarity in a fraction of acini. This behavior was directly related to the ability of the tumor myoepithelial cells to produce {alpha}-1 chain of laminin. In vivo, breast carcinomas were either negative for laminin-1 (7/12 biopsies) or showed a focal, fragmented deposition of a less intensely stained basement membrane (5/12 biopsies). Dual staining with myoepithelial markers revealed that tumorassociated myoepithelial cells were either negative or weakly positive for expression of laminin-1, establishing a strong correlation between loss of laminin-1 and breast cancer. We conclude that the double-layered breast acinus may be

  18. Contextual sensitivity in scientific reproducibility.

    Science.gov (United States)

    Van Bavel, Jay J; Mende-Siedlecki, Peter; Brady, William J; Reinero, Diego A

    2016-06-01

    In recent years, scientists have paid increasing attention to reproducibility. For example, the Reproducibility Project, a large-scale replication attempt of 100 studies published in top psychology journals found that only 39% could be unambiguously reproduced. There is a growing consensus among scientists that the lack of reproducibility in psychology and other fields stems from various methodological factors, including low statistical power, researcher's degrees of freedom, and an emphasis on publishing surprising positive results. However, there is a contentious debate about the extent to which failures to reproduce certain results might also reflect contextual differences (often termed "hidden moderators") between the original research and the replication attempt. Although psychologists have found extensive evidence that contextual factors alter behavior, some have argued that context is unlikely to influence the results of direct replications precisely because these studies use the same methods as those used in the original research. To help resolve this debate, we recoded the 100 original studies from the Reproducibility Project on the extent to which the research topic of each study was contextually sensitive. Results suggested that the contextual sensitivity of the research topic was associated with replication success, even after statistically adjusting for several methodological characteristics (e.g., statistical power, effect size). The association between contextual sensitivity and replication success did not differ across psychological subdisciplines. These results suggest that researchers, replicators, and consumers should be mindful of contextual factors that might influence a psychological process. We offer several guidelines for dealing with contextual sensitivity in reproducibility. PMID:27217556

  19. Planar cell polarity effector gene Intu regulates cell fate-specific differentiation of keratinocytes through the primary cilia.

    Science.gov (United States)

    Dai, D; Li, L; Huebner, A; Zeng, H; Guevara, E; Claypool, D J; Liu, A; Chen, J

    2013-01-01

    Genes involved in the planar cell polarity (PCP) signaling pathway are essential for a number of developmental processes in mammals, such as convergent extension and ciliogenesis. Tissue-specific PCP effector genes of the PCP signaling pathway are believed to mediate PCP signals in a tissue- and cell type-specific manner. However, how PCP signaling controls the morphogenesis of mammalian tissues remains unclear. In this study, we investigated the role of inturned (Intu), a tissue-specific PCP effector gene, during hair follicle formation in mice. Tissue-specific disruption of Intu in embryonic epidermis resulted in hair follicle morphogenesis arrest because of the failure of follicular keratinocyte to differentiate. Targeting Intu in the epidermis resulted in almost complete loss of primary cilia in epidermal and follicular keratinocytes, and a suppressed hedgehog signaling pathway. Surprisingly, the epidermal stratification and differentiation programs and barrier function were not affected. These results demonstrate that tissue-specific PCP effector genes of the PCP signaling pathway control the differentiation of keratinocytes through the primary cilia in a cell fate- and context-dependent manner, which may be critical in orchestrating the propagation and interpretation of polarity signals established by the core PCP components. PMID:22935613

  20. Dkk-1 Inhibits Intestinal Epithelial Cell Migration by Attenuating Directional Polarization of Leading Edge Cells

    OpenAIRE

    Koch, Stefan; Capaldo, Christopher T.; Samarin, Stanislav; Nava, Porfirio; Neumaier, Irmgard; Skerra, Arne; Sacks, David B; Parkos, Charles A.; Nusrat, Asma

    2009-01-01

    Wnt signaling pathways regulate proliferation, motility, and survival in a variety of human cell types. Dickkopf-1 (Dkk-1) is a secreted Wnt antagonist that has been proposed to regulate tissue homeostasis in the intestine. In this report, we show that Dkk-1 is secreted by intestinal epithelial cells after wounding and that it inhibits cell migration by attenuating the directional orientation of migrating epithelial cells. Dkk-1 exposure induced mislocalized activation of Cdc42 in migrating c...

  1. Absence of transepithelial anion exchange by rabbit OMCD: Evidence against reversal of cell polarity

    International Nuclear Information System (INIS)

    In the rabbit cortical collecting duct (CCD), Cl tracer crosses the epithelium predominantly via an anion exchange system that operates in either a Cl-Cl or Cl-HCO3 exchange mode. In the present study, the authors used the 36Cl lumen-to-bath rate coefficient (KCl, nm/s), a sensitive measurement of CCD transepithelial anion transport, to investigate the nature of Cl transport in the medullary collecting duct dissected from inner stripe, outer medulla (OMCD). The KCl in OMCD perfused and bathed in HCO3-Ringer solution was low and similar to that value observed in the CCD when anion exchange is inhibited and Cl permeates the epithelium by diffusion. To test the hypothesis that metabolic alkalosis could reverse the polarity of intercalated cells and thus induce an apical Cl-HCO3 exchanger in H+-secreting OMCD cells, they measured KCl in OMCD from rabbits make alkalotic by deoxycorticosterone and furosemide. Although the base-line KCl was slightly higher than in OMCD from control rabbits, the value was still far lower than the KCl under comparable conditions in CCD. They conclude (1) Cl transport across the MCD by anion exchange is immeasurably low or nonexistent; (2) unlike the CCD, Cl transport in OMCD is not responsive to cAMP; and (3) metabolic alkalosis does not induce an apical anion exchanger in OMCD, i.e., does not cause epithelial polarity reversal

  2. 10.6% Certified Colloidal Quantum Dot Solar Cells via Solvent-Polarity-Engineered Halide Passivation.

    Science.gov (United States)

    Lan, Xinzheng; Voznyy, Oleksandr; García de Arquer, F Pelayo; Liu, Mengxia; Xu, Jixian; Proppe, Andrew H; Walters, Grant; Fan, Fengjia; Tan, Hairen; Liu, Min; Yang, Zhenyu; Hoogland, Sjoerd; Sargent, Edward H

    2016-07-13

    Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaics with broad spectral absorption tunability. Major advances in their efficiency have been made via improved CQD surface passivation and device architectures with enhanced charge carrier collection. Herein, we demonstrate a new strategy to improve further the passivation of CQDs starting from the solution phase. A cosolvent system is employed to tune the solvent polarity in order to achieve the solvation of methylammonium iodide (MAI) and the dispersion of hydrophobic PbS CQDs simultaneously in a homogeneous phase, otherwise not achieved in a single solvent. This process enables MAI to access the CQDs to confer improved passivation. This, in turn, allows for efficient charge extraction from a thicker photoactive layer device, leading to a certified solar cell power conversion efficiency of 10.6%, a new certified record in CQD photovoltaics. PMID:27351104

  3. MHV-A59 enters polarized murine epithelial cells through the apical surface but is released basolaterally

    NARCIS (Netherlands)

    Rossen, J W; Voorhout, W F; Horzinek, M C; van der Ende, A; Strous, G J; Rottier, P J

    1995-01-01

    Coronaviruses have a marked tropism for epithelial cells. Entry and release of the porcine transmissible gastroenteritis virus (TGEV) is restricted to apical surfaces of polarized epithelial cells, as we have recently shown (J. W. A. Rossen, C. P. J. Bekker, W. F. Voorhout, G. J. A. M. Strous, A. va

  4. Reproducible research in signal processing

    OpenAIRE

    Vandewalle Patrick; Pesquet-Popescu Beatrice; Pérez-Neira Ana; Zoubir Abdelhak; Gini Fulvio; Pikrakis Aggelos; Rupp Markus; Sankur Bulent

    2011-01-01

    Reproducible research results become more and more an important issue as systems under investigation are growing permanently in complexity, and it becomes thus almost impossible to judge the accuracy of research results merely on the bare paper presentation.

  5. Open Science and Research Reproducibility

    Science.gov (United States)

    Munafò, Marcus

    2016-01-01

    Many scientists, journals and funders are concerned about the low reproducibility of many scientific findings. One approach that may serve to improve the reliability and robustness of research is open science. Here I argue that the process of pre-registering study protocols, sharing study materials and data, and posting preprints of manuscripts may serve to improve quality control procedures at every stage of the research pipeline, and in turn improve the reproducibility of published work. PMID:27350794

  6. How actin/myosin crosstalks guide the adhesion, locomotion and polarization of cells.

    Science.gov (United States)

    Sackmann, Erich

    2015-11-01

    Cell-tissue-tissue interaction is determined by specific short range forces between cell adhesion molecules (CAMs) and ligands of the tissue, long range repulsion forces mediated by cell surface grafted macromolecules and adhesion-induced elastic stresses in the cell envelope. This interplay of forces triggers the rapid random clustering of tightly coupled linkers. By coupling of actin gel patches to the intracellular domains of the CAMs, these clusters can grow in a secondary process resulting in the formation of functional adhesion microdomains (ADs). The ADs can act as biochemical steering centers by recruiting and activating functional proteins, such as GTPases and associated regulating proteins, through electrostatic-hydrophobic forces with cationic lipid domains that act as attractive centers. First, I summarize physical concepts of cell adhesion revealed by studies of biomimetic systems. Then I describe the role of the adhesion domains as biochemical signaling platforms and force transmission centers promoting cellular protrusions, in terms of a shell string model of cells. Protrusion forces are generated by actin gelation triggered by molecular machines (focal adhesion kinase (FAK), Src-kinases and associated adaptors) which assemble around newly formed integrin clusters. They recruit and activate the GTPases Rac-1 and actin gelation promoters to charged membrane domains via electrostatic-hydrophobic forces. The cell front is pushed forward in a cyclic and stepwise manner and the step-width is determined by the dynamics antagonistic interplay between Rac-1 and RhoA. The global cell polarization in the direction of motion is mediated by the actin-microtubule (MT) crosstalk at adhesion domains. Supramolecular actin-MT assemblies at the front help to promote actin polymerization. At the rear they regulate the dismantling of the ADs through the Ca(++)-mediated activation of the protease calpain and trigger their disruption by RhoA mediated contraction via

  7. Aqueous humor enhances the proliferation of rat retinal precursor cells in culture, and this effect is partially reproduced by ascorbic acid

    DEFF Research Database (Denmark)

    Yang, Jing; Klassen, Henry; Pries, Mette; Wang, Wei; Nissen, Mogens H

    2006-01-01

    Aqueous humor has been shown to influence the proliferation of various ocular cell types, but the effect on immature retinal cells is not known. Here, the effect of pig aqueous humor on the proliferation of rat retinal precursor cells (RPCs) was investigated. RPCs were prepared from embryonic day...... [(3)H]thymidine incorporation by as much as 317%, as compared with controls. Aqueous supplementation also increased both the number and size of RPC spherical aggregates ("spheres") over the first 4 days, consistent with increased proliferative activity. Using gel filtration and the in vitro...... activity present in aqueous humor. These results highlight the potential role of soluble factors present in the cellular microenvironment with respect to modulation of endogenous progenitor cell activity....

  8. Polar flagellar biosynthesis and a regulator of flagellar number influence spatial parameters of cell division in Campylobacter jejuni.

    Directory of Open Access Journals (Sweden)

    Murat Balaban

    2011-12-01

    Full Text Available Spatial and numerical regulation of flagellar biosynthesis results in different flagellation patterns specific for each bacterial species. Campylobacter jejuni produces amphitrichous (bipolar flagella to result in a single flagellum at both poles. These flagella confer swimming motility and a distinctive darting motility necessary for infection of humans to cause diarrheal disease and animals to promote commensalism. In addition to flagellation, symmetrical cell division is spatially regulated so that the divisome forms near the cellular midpoint. We have identified an unprecedented system for spatially regulating cell division in C. jejuni composed by FlhG, a regulator of flagellar number in polar flagellates, and components of amphitrichous flagella. Similar to its role in other polarly-flagellated bacteria, we found that FlhG regulates flagellar biosynthesis to limit poles of C. jejuni to one flagellum. Furthermore, we discovered that FlhG negatively influences the ability of FtsZ to initiate cell division. Through analysis of specific flagellar mutants, we discovered that components of the motor and switch complex of amphitrichous flagella are required with FlhG to specifically inhibit division at poles. Without FlhG or specific motor and switch complex proteins, cell division occurs more often at polar regions to form minicells. Our findings suggest a new understanding for the biological requirement of the amphitrichous flagellation pattern in bacteria that extend beyond motility, virulence, and colonization. We propose that amphitrichous bacteria such as Campylobacter species advantageously exploit placement of flagella at both poles to spatially regulate an FlhG-dependent mechanism to inhibit polar cell division, thereby encouraging symmetrical cell division to generate the greatest number of viable offspring. Furthermore, we found that other polarly-flagellated bacteria produce FlhG proteins that influence cell division, suggesting that

  9. Towards Reproducibility in Computational Hydrology

    Science.gov (United States)

    Hutton, Christopher; Wagener, Thorsten; Freer, Jim; Han, Dawei

    2016-04-01

    The ability to reproduce published scientific findings is a foundational principle of scientific research. Independent observation helps to verify the legitimacy of individual findings; build upon sound observations so that we can evolve hypotheses (and models) of how catchments function; and move them from specific circumstances to more general theory. The rise of computational research has brought increased focus on the issue of reproducibility across the broader scientific literature. This is because publications based on computational research typically do not contain sufficient information to enable the results to be reproduced, and therefore verified. Given the rise of computational analysis in hydrology over the past 30 years, to what extent is reproducibility, or a lack thereof, a problem in hydrology? Whilst much hydrological code is accessible, the actual code and workflow that produced and therefore documents the provenance of published scientific findings, is rarely available. We argue that in order to advance and make more robust the process of hypothesis testing and knowledge creation within the computational hydrological community, we need to build on from existing open data initiatives and adopt common standards and infrastructures to: first make code re-useable and easy to find through consistent use of metadata; second, publish well documented workflows that combine re-useable code together with data to enable published scientific findings to be reproduced; finally, use unique persistent identifiers (e.g. DOIs) to reference re-useable and reproducible code, thereby clearly showing the provenance of published scientific findings. Whilst extra effort is require to make work reproducible, there are benefits to both the individual and the broader community in doing so, which will improve the credibility of the science in the face of the need for societies to adapt to changing hydrological environments.

  10. Mn bioavailability by polarized Caco-2 cells: comparison between Mn gluconate and Mn oxyprolinate

    Directory of Open Access Journals (Sweden)

    Fulgenzi Alessandro

    2011-07-01

    Full Text Available Abstract Background Micronutrient inadequate intake is responsible of pathological deficiencies and there is a need of assessing the effectiveness of metal supplementation, frequently proposed to rebalance poor diets. Manganese (Mn is present in many enzymatic intracellular systems crucial for the regulation of cell metabolism, and is contained in commercially available metal supplements. Methods We compared the effects of two different commercial Mn forms, gluconate (MnGluc and oxyprolinate (MnOxP. For this purpose we used the polarized Caco-2 cells cultured on transwell filters, an established in vitro model of intestinal epithelium. Since micronutrient deficiency may accelerate mitochondrial efficiency, the mitochondrial response of these cells, in the presence of MnGluc and MnOxP, by microscopy methods and by ATP luminescence assay was used. Results In the presence of both MnOxP and MnGluc a sustained mitochondrial activity was shown by mitoTraker labeling (indicative of mitochondrial respiration, but ATP intracellular content remained comparable to untreated cells only in the presence of MnOxP. In addition MnOxP transiently up-regulated the antioxidant enzyme Mn superoxide dismutase more efficiently than MnGluc. Both metal treatments preserved NADH and βNADPH diaphorase oxidative activity, avoided mitochondrial dysfunction, as assessed by the absence of a sustained phosphoERK activation, and were able to maintain cell viability. Conclusions Collectively, our data indicate that MnOxP and MnGluc, and primarily the former, produce a moderate and safe modification of Caco-2 cell metabolism, by activating positive enzymatic mechanisms, thus could contribute to long-term maintenance of cell homeostasis.

  11. The dual effects of polar methanolic extract of Hypericum perforatum L. in bladder cancer cells

    Science.gov (United States)

    Nseyo, U. O.; Nseyo, O. U.; Shiverick, K. T.; Medrano, T.; Mejia, M.; Stavropoulos, N.; Tsimaris, I.; Skalkos, D.

    2007-02-01

    Introduction and background: We have reported on the polar methanolic fraction (PMF) of Hypericum Perforatum L as a novel photosensitizing agent for photodynamic therapy (PDT) and photodynamic diagnosis (PDD). PMF has been tested in human leukemic cells, HL-60 cells, cord blood hemopoietic progenitor cells, bladder cancers derived from metastatic lymph node (T-24) and primary papillary bladder lesion (RT-4). However, the mechanisms of the effects of PMF on these human cell lines have not been elucidated. We have investigated mechanisms of PMF + light versus PMF-alone (dark experiment) in T-24 human bladder cancer cells. Methods: PMF was prepared from an aerial herb of HPL which was brewed in methanol and extracted with ether and methanol. Stock solutions of PMF were made in DSMO and stored in dark conditions. PMF contains 0.57% hypericin and 2.52% hyperforin. The T24 cell line was obtained from American Type Culture Collection (ATCC). In PDT treatment, PMF (60μg/ml) was incubated with cells, which were excited with laser light (630nm) 24 hours later. Apoptosis was determined by DNA fragmentation/laddering assay. DNA isolation was performed according to the manufacture's instructions with the Kit (Oncogene Kit#AM41). Isolated DNA samples were separated by electrophoresis in 1.5% in agarose gels and bands were visualized by ethidium bromide labeling. The initial cell cycle analysis and phase distribution was by flow cytometry. DNA synthesis was measured by [3H] thymidine incorporation, and cell cycle regulatory proteins were assayed by Western immunoblot. Results: The results of the flow cytometry showed PMF +light induced significant (40%) apoptosis in T24 cells, whereas Light or PMF alone produced little apoptosis. The percentage of cells in G 0/G I phase was decreased by 25% and in G2/M phase by 38%. The main impact was observed on the S phase which was blocked by 78% from the specific photocytotoxic process. DNA laddering analysis showed that PMF (60

  12. Directional memory arises from long-lived cytoskeletal asymmetries in polarized chemotactic cells.

    Science.gov (United States)

    Prentice-Mott, Harrison V; Meroz, Yasmine; Carlson, Andreas; Levine, Michael A; Davidson, Michael W; Irimia, Daniel; Charras, Guillaume T; Mahadevan, L; Shah, Jagesh V

    2016-02-01

    Chemotaxis, the directional migration of cells in a chemical gradient, is robust to fluctuations associated with low chemical concentrations and dynamically changing gradients as well as high saturating chemical concentrations. Although a number of reports have identified cellular behavior consistent with a directional memory that could account for behavior in these complex environments, the quantitative and molecular details of such a memory process remain unknown. Using microfluidics to confine cellular motion to a 1D channel and control chemoattractant exposure, we observed directional memory in chemotactic neutrophil-like cells. We modeled this directional memory as a long-lived intracellular asymmetry that decays slower than observed membrane phospholipid signaling. Measurements of intracellular dynamics revealed that moesin at the cell rear is a long-lived element that when inhibited, results in a reduction of memory. Inhibition of ROCK (Rho-associated protein kinase), downstream of RhoA (Ras homolog gene family, member A), stabilized moesin and directional memory while depolymerization of microtubules (MTs) disoriented moesin deposition and also reduced directional memory. Our study reveals that long-lived polarized cytoskeletal structures, specifically moesin, actomyosin, and MTs, provide a directional memory in neutrophil-like cells even as they respond on short time scales to external chemical cues. PMID:26764383

  13. Analysis of polarization methods for elimination of power overshoot in microbial fuel cells

    KAUST Repository

    Watson, Valerie J.

    2011-01-01

    Polarization curves from microbial fuel cells (MFCs) often show an unexpectedly large drop in voltage with increased current densities, leading to a phenomenon in the power density curve referred to as "power overshoot". Linear sweep voltammetry (LSV, 1 mV s- 1) and variable external resistances (at fixed intervals of 20 min) over a single fed-batch cycle in an MFC both resulted in power overshoot in power density curves due to anode potentials. Increasing the anode enrichment time from 30 days to 100 days did not eliminate overshoot, suggesting that insufficient enrichment of the anode biofilm was not the primary cause. Running the reactor at a fixed resistance for a full fed-batch cycle (~ 1 to 2 days), however, completely eliminated the overshoot in the power density curve. These results show that long times at a fixed resistance are needed to stabilize current generation by bacteria in MFCs, and that even relatively slow LSV scan rates and long times between switching circuit loads during a fed-batch cycle may produce inaccurate polarization and power density results for these biological systems. © 2010 Elsevier B.V. All rights reserved.

  14. Down-Regulation of Cell Surface Receptors Is Modulated by Polar Residues within the Transmembrane Domain

    Science.gov (United States)

    Zaliauskiene, Lolita; Kang, Sunghyun; Brouillette, Christie G.; Lebowitz, Jacob; Arani, Ramin B.; Collawn, James F.

    2000-01-01

    How recycling receptors are segregated from down-regulated receptors in the endosome is unknown. In previous studies, we demonstrated that substitutions in the transferrin receptor (TR) transmembrane domain (TM) convert the protein from an efficiently recycling receptor to one that is rapidly down regulated. In this study, we demonstrate that the “signal” within the TM necessary and sufficient for down-regulation is Thr11Gln17Thr19 (numbering in TM). Transplantation of these polar residues into the wild-type TR promotes receptor down-regulation that can be demonstrated by changes in protein half-life and in receptor recycling. Surprisingly, this modification dramatically increases the TR internalization rate as well (∼79% increase). Sucrose gradient centrifugation and cross-linking studies reveal that propensity of the receptors to self-associate correlates with down-regulation. Interestingly, a number of cell surface proteins that contain TM polar residues are known to be efficiently down-regulated, whereas recycling receptors for low-density lipoprotein and transferrin conspicuously lack these residues. Our data, therefore, suggest a simple model in which specific residues within the TM sequences dramatically influence the fate of membrane proteins after endocytosis, providing an alternative signal for down-regulation of receptor complexes to the well-characterized cytoplasmic tail targeting signals. PMID:10930460

  15. High performance single step co-fired solid oxide fuel cells (SOFC): Polarization measurements and analysis

    Science.gov (United States)

    Yoon, Kyung Joong

    At present, one of the major obstacles for the commercialization of solid oxide fuel cell (SOFC) power systems is their high manufacturing costs expressed in terms of SOFC system cost per unit power ($/kW). In this work, anode-supported planar SOFCs were fabricated by a cost-competitive single step co-firing process. The cells were comprised of a porous Ni + yittria-stabilized zirconia (YSZ) anode support, a porous-fine-grained Ni + YSZ anode active layer for some experiments, a dense YSZ electrolyte, a porous-fine-grained Ca-doped LaMnO3 (LCM) + YSZ cathode active layer, and a porous LCM cathode current collector layer. The fabrication process involved tape casting or high shear compaction (HSC) of the anode support followed by screen printing of the remaining component layers. The cells were then co-fired at 1300˜1340°C for 2 hours. The performance of the cell fabricated with the tape casting anode was improved by minimizing various polarization losses through experimental and theoretical modeling approaches, and the maximum power density of 1.5 W/cm 2 was obtained at 800°C with humidified hydrogen (3% H2O) and air. The cells were also tested with various compositions of humidified hydrogen (3˜70% H2O) to simulate the effect of practical fuel utilization on the cell performance. Based on these measurements, an analytical model describing anodic reactions was developed to understand reaction kinetics and rate limiting steps. The cell performance at high fuel utilization was significantly improved by increasing the number of the reaction sites near the anode-electrolyte interface. For anode substrate fabrication, the HSC process offers many advantages such as low fabrication costs, high production throughput, and good control of shrinkage and thickness over the conventional tape casting process. HSC process was successfully employed in single step co-firing process, and SOFCs fabricated with HSC anodes showed adequate performance both at low and high fuel

  16. Interferon-γ and Tumor Necrosis Factor-α Polarize Bone Marrow Stromal Cells Uniformly to a Th1 Phenotype.

    Science.gov (United States)

    Jin, Ping; Zhao, Yuanlong; Liu, Hui; Chen, Jinguo; Ren, Jiaqiang; Jin, Jianjian; Bedognetti, Davide; Liu, Shutong; Wang, Ena; Marincola, Francesco; Stroncek, David

    2016-01-01

    Activated T cells polarize mesenchymal stromal cells (MSCs) to a proinflammatory Th1 phenotype which likely has an important role in amplifying the immune response in the tumor microenvironment. We investigated the role of interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), two factors produced by activated T cells, in MSC polarization. Gene expression and culture supernatant analysis showed that TNF-α and IFN-γ stimulated MSCs expressed distinct sets of proinflammatory factors. The combination of IFN-γ and TNF-α was synergistic and induced a transcriptome most similar to that found in MSCs stimulated with activated T cells and similar to that found in the inflamed tumor microenvironment; a Th1 phenotype with the expression of the immunosuppressive factors IL-4, IL-10, CD274/PD-L1 and indoleamine 2,3 dioxygenase (IDO). Single cell qRT-PCR analysis showed that the combination of IFN-γ and TNF-α polarized uniformly to this phenotype. The combination of IFN-γ and TNF-α results in the synergist uniform polarization of MSCs toward a primarily Th1 phenotype. The stimulation of MSCs by IFN-γ and TNF-α released from activated tumor infiltrating T cells is likely responsible for the production of many factors that characterize the tumor microenvironment. PMID:27211104

  17. Endothelial Cell Migration and Vascular Endothelial Growth Factor Expression Are the Result of Loss of Breast Tissue Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Amy; Cuevas, Ileana; Kenny, Paraic A; Miyake, Hiroshi; Mace, Kimberley; Ghajar, Cyrus; Boudreau, Aaron; Bissell, Mina; Boudreau, Nancy

    2009-05-26

    Recruiting a new blood supply is a rate-limiting step in tumor progression. In a three-dimensional model of breast carcinogenesis, disorganized, proliferative transformed breast epithelial cells express significantly higher expression of angiogenic genes compared with their polarized, growth-arrested nonmalignant counterparts. Elevated vascular endothelial growth factor (VEGF) secretion by malignant cells enhanced recruitment of endothelial cells (EC) in heterotypic cocultures. Significantly, phenotypic reversion of malignant cells via reexpression of HoxD10, which is lost in malignant progression, significantly attenuated VEGF expression in a hypoxia-inducible factor 1{alpha}-independent fashion and reduced EC migration. This was due primarily to restoring polarity: forced proliferation of polarized, nonmalignant cells did not induce VEGF expression and EC recruitment, whereas disrupting the architecture of growth-arrested, reverted cells did. These data show that disrupting cytostructure activates the angiogenic switch even in the absence of proliferation and/or hypoxia and restoring organization of malignant clusters reduces VEGF expression and EC activation to levels found in quiescent nonmalignant epithelium. These data confirm the importance of tissue architecture and polarity in malignant progression.

  18. The reduction half cell in biomaterials corrosion: oxygen diffusion profiles near and cell response to polarized titanium surfaces.

    Science.gov (United States)

    Gilbert, J L; Zarka, L; Chang, E; Thomas, C H

    1998-11-01

    Mechanically assisted corrosion processes can greatly increase the oxidation currents generated in passivating alloy systems like Co-Cr and titanium due to oxide film disruption. When oxide films are abraded, repassivation and ionic dissolution both occur at rates that are orders of magnitude higher than undisrupted surfaces. The excess electrons generated by these anodic processes must be consumed in corresponding reduction reactions that include the reduction of oxygen. If large enough, these reduction reactions may locally deplete the concentration of solution-dissolved oxygen and, in turn, affect cell behavior in the vicinity of the implant surface. To date, this hypothesis has not been tested. In the present study, a scanning electrochemical microscope was used to measure oxygen concentration profiles in vitro near a planar titanium electrode polarized to different voltages representative of those attainable by titanium undergoing mechanically assisted corrosion. The potentials investigated ranged from 0 mV to -1000 mV (AgCl). The oxygen concentration as a function of distance from the titanium surface was measured using a platinum-iridium microelectrode and an amperometric technique. Also, preliminary experiments were performed to assess the response of rat calvarial osteoblast-rich cells cultured for 2 h on titanium samples polarized to two different potentials (0 mV and -1000 mV versus AgCl). The results of this study indicate that oxygen concentrations near titanium surfaces are affected by sample potentials out to probe-sample distances as great as 500 microm. Within 2 microm of the surface, oxygen concentrations decreased by 15 to 25% for sample potentials between -100 and -500 mV. At potentials more negative than -600 mV, the oxygen concentration dropped rapidly to near zero by -900 mV. The cell experiments showed a statistically significant difference in the amount of cell spreading, as measured by projected cell area, between the two groups (p < 0

  19. Planar cell polarity enables posterior localization of nodal cilia and left-right axis determination during mouse and Xenopus embryogenesis.

    Directory of Open Access Journals (Sweden)

    Dragana Antic

    Full Text Available Left-right asymmetry in vertebrates is initiated in an early embryonic structure called the ventral node in human and mouse, and the gastrocoel roof plate (GRP in the frog. Within these structures, each epithelial cell bears a single motile cilium, and the concerted beating of these cilia produces a leftward fluid flow that is required to initiate left-right asymmetric gene expression. The leftward fluid flow is thought to result from the posterior tilt of the cilia, which protrude from near the posterior portion of each cell's apical surface. The cells, therefore, display a morphological planar polarization. Planar cell polarity (PCP is manifested as the coordinated, polarized orientation of cells within epithelial sheets, or as directional cell migration and intercalation during convergent extension. A set of evolutionarily conserved proteins regulates PCP. Here, we provide evidence that vertebrate PCP proteins regulate planar polarity in the mouse ventral node and in the Xenopus gastrocoel roof plate. Asymmetric anterior localization of VANGL1 and PRICKLE2 (PK2 in mouse ventral node cells indicates that these cells are planar polarized by a conserved molecular mechanism. A weakly penetrant Vangl1 mutant phenotype suggests that compromised Vangl1 function may be associated with left-right laterality defects. Stronger functional evidence comes from the Xenopus GRP, where we show that perturbation of VANGL2 protein function disrupts the posterior localization of motile cilia that is required for leftward fluid flow, and causes aberrant expression of the left side-specific gene Nodal. The observation of anterior-posterior PCP in the mouse and in Xenopus embryonic organizers reflects a strong evolutionary conservation of this mechanism that is important for body plan determination.

  20. Dynamics of Cdc42 network embodies a Turing-type mechanism of yeast cell polarity.

    Science.gov (United States)

    Goryachev, Andrew B; Pokhilko, Alexandra V

    2008-04-30

    Complex biochemical networks can be understood by identifying their principal regulatory motifs and mode of action. We model the early phase of budding yeast cellular polarization and show that the biochemical processes in the presumptive bud site comprise a Turing-type mechanism. The roles of the prototypical activator and substrate are played by GTPase Cdc42 in its active and inactive states, respectively. We demonstrate that the nucleotide cycling of Cdc42 converts cellular energy into a stable cluster of activated Cdc42. This energy drives a continuous membrane-cytoplasmic exchange of the cluster components to counteract diffusive spread of the cluster. This exchange explains why only one bud forms per cell cycle, because the winner-takes-all competition of candidate sites inevitably selects a single site. PMID:18381072

  1. Reproducible Research in Speech Sciences

    Directory of Open Access Journals (Sweden)

    Kandaacute;lmandaacute;n Abari

    2012-11-01

    Full Text Available Reproducible research is the minimum standard of scientific claims in cases when independent replication proves to be difficult. With the special combination of available software tools, we provide a reproducibility recipe for the experimental research conducted in some fields of speech sciences. We have based our model on the triad of the R environment, the EMU-format speech database, and the executable publication. We present the use of three typesetting systems (LaTeX, Markdown, Org, with the help of a mini research.

  2. Lentiviral vectors containing an enhancer-less ubiquitously acting chromatin opening element (UCOE) provide highly reproducible and stable transgene expression in hematopoietic cells

    OpenAIRE

    Zhang, F.; Thornhill, S. I.; Howe, S. J.; Ulaganathan, M.; Scharnbach, A.; Sinclair, J; Kinnon, C.; Gaspar, H. B.; Antoniou, M; Thrasher, A. J.

    2007-01-01

    Ubiquitously acting chromatin opening elements (UCOEs) consist of methylation-free CpG islands encompassing dual divergently transcribed promoters of housekeeping genes that have been shown to confer resistance to transcriptional silencing and to produce consistent and stable transgene expression in tissue culture systems. To develop improved strategies for hematopoietic cell gene therapy, we have assessed the potential of the novel human HNRPA2B1-CBX3 UCOE (A2UCOE) within the context of a se...

  3. Autophagy protects human brain microvascular endothelial cells against methylglyoxal-induced injuries, reproducible in a cerebral ischemic model in diabetic rats.

    Science.gov (United States)

    Fang, Lili; Li, Xue; Zhong, Yinbo; Yu, Jing; Yu, Lina; Dai, Haibin; Yan, Min

    2015-10-01

    Cerebral microvascular endothelial cells (ECs) are crucial for brain vascular repair and maintenance, but their physiological function may be impaired during ischemic stroke and diabetes. Methylglyoxal (MGO), a reactive dicarbonyl produced during glucose metabolism, could exacerbate ischemia-induced EC injury and dysfunction. We investigated the protective effect of autophagy on cultured human brain microvascular endothelial cells (HBMEC) that underwent MGO treatment. A further study was conducted to explore the underlying mechanisms of the protective effect. Autophagic activity was assessed by evaluating protein levels, using western blot. 3-methyladenine (3-MA), bafilomycin A1, ammonium chloride (AC), Beclin 1 siRNA, and chloroquine (CQ) were used to cause autophagy inhibition. Alarmar blue assay and lactate dehydrogenase release assay were used to evaluate cell viability. Streptozotocin was administered to induce type I diabetes in rats and post-permanent middle cerebral artery occlusion was performed to elicit cerebral ischemia. Blood-brain barrier permeability was also assessed. Our study found that MGO reduced HBMEC cell viability in a concentration- and time-dependent manner, and triggered the responsive autophagy activation. Autophagy inhibitors bafilomycin A1, AC, 3-MA, and BECN1 siRNA exacerbated MGO-induced HBMEC injury. FAK phosphorylation inhibitor PF573228 inhibited MGO-triggered autophagy and enhanced lactate dehydrogenase release. Meanwhile, similar autophagy activation in brain vascular ECs was observed during permanent middle cerebral artery occlusion-induced cerebral ischemia in diabetic rats, while chloroquine-induced autophagy inhibition enhanced blood-brain barrier permeability. Taken together, our study indicates that autophagy triggered by MGO defends HBMEC against injuries. PMID:26251121

  4. Polarized neural stem cells derived from adult bone marrow stromal cells develop a rosette-like structure.

    Science.gov (United States)

    Darabi, Shahram; Tiraihi, Taki; Ruintan, Atefeh; Abbaszadeh, Hojatt Allah; Delshad, AliReza; Taheri, Taher

    2013-09-01

    Bone marrow stromal cells (BMSCs) were reported to form floating aggregation of cells with expression of nestin, a marker for neural stem cells (NSCs). The purpose of this investigation is to evaluate the morphology and the molecular markers expressed by NSCs derived from these neurospheres. The BMSCs were isolated from Sprague Dawley rats and evaluated for osteogenesis, lipogenesis, and expression of fibronectin, CD90, CD106, CD31, and Oct4. The BMSCs were cultured with Dulbecco's modified Eagle's medium (DMEM)/F12 containing 15% fetal bovine serum, then with DMEM/F12 containing 2% B27, basic fibroblast growth factor, and epidermal growth factor. The cell aggregates or spheres were stained with acridine orange, which showed that the neurospheres comprised aggregated cells at either premitotic/postsynthetic (PS), postmitotic/presynthetic (PM) phases of cell cycle, or a mixture of both. The NSCs harvested from the neurospheres were polar with eccentric nucleus, and at either a PS or a PM cell cycle phases, some cells at the latter phase tended to form rosette-like structures. The cells were immunostained for molecular markers such as nestin, neurofilament 68 (NF68), NF160, and NF200 and glial fibrillary acidic protein (GFAP). Myelin basic protein (MBP), the pluripotency (Oct4, Nanog, and SOX2), and the differentiation genes (NeuroD1, Tubb4, and Musashi I) were also evaluated using reverse transcription polymerase chain reaction (RT-PCR). Nestin, NF68, NF160, NF200, GFAP, O4, and N-cadherin were expressed in the NSCs. The percentage of immunoreactive cells to nestin was significantly higher than that of the other neuronal markers. MBP was not expressed in BMSCs, neurospheres, and NSCs. The neurospheres were immunoreactive to GFAP. RT-PCR showed the expression of NeuroD1 and Musashi I. The pluripotency gene (SOX2) was expressed in NSCs. Oct4 and Nanog were expressed in BMSCs, while Oct4 and SOX2 were expressed in the neurosphere. This indicates that a pluripotency

  5. Polarizing T and B cell responses by APC-targeted subunit vaccines.

    Directory of Open Access Journals (Sweden)

    Gunnveig eGrødeland

    2015-07-01

    Full Text Available Current influenza vaccines mostly aim at the induction of specific neutralizing antibodies. While antibodies are important for protection against a particular virus strain, T cells can recognize epitopes that will offer broader protection against influenza. We have previously developed a DNA vaccine format by which protein antigens can be targeted specifically to receptors on antigen presenting cells (APCs. The DNA-encoded vaccine proteins are homodimers, each chain consisting of a targeting unit, a dimerization unit, and an antigen. The strategy of targeting antigen to APCs greatly enhances immune responses as compared to non-targeted controls. Furthermore, targeting of antigen to different receptors on APCs can polarize the immune response to different arms of immunity. Here, we discuss how targeting of hemagglutinin (HA to MHC class II molecules increases Th2 and IgG1 antibody responses, whereas targeting to chemokine receptors XCR1 or CCR1/3/5 increases Th1 and IgG2a responses, in addition to CD8+ T cell responses. We also discuss these results in relation to work published by others on APC-targeting. Differential targeting of APC surface molecules may allow the induction of tailor-made phenotypes of adaptive immune responses that are optimal for protection against various infectious agents, including influenza virus.

  6. Signaling at the inhibitory natural killer cell immune synapse regulates lipid raft polarization but not class I MHC clustering.

    Science.gov (United States)

    Fassett, M S; Davis, D M; Valter, M M; Cohen, G B; Strominger, J L

    2001-12-01

    Natural killer (NK) cell cytotoxicity is determined by a balance of positive and negative signals. Negative signals are transmitted by NK inhibitory receptors (killer immunoglobulin-like receptors, KIR) at the site of membrane apposition between an NK cell and a target cell, where inhibitory receptors become clustered with class I MHC ligands in an organized structure known as an inhibitory NK immune synapse. Immune synapse formation in NK cells is poorly understood. Because signaling by NK inhibitory receptors could be involved in this process, the human NK tumor line YTS was transfected with signal-competent and signal-incompetent KIR2DL1. The latter were generated by truncating the KIR2DL1 cytoplasmic tail or by introducing mutations in the immunoreceptor tyrosine-based inhibition motifs. The KIR2DL1 mutants retained their ability to cluster class I MHC ligands on NK cell interaction with appropriate target cells. Therefore, receptor-ligand clustering at the inhibitory NK immune synapse occurs independently of KIR2DL1 signal transduction. However, parallel examination of NK cell membrane lipid rafts revealed that KIR2DL1 signaling is critical for blocking lipid raft polarization and NK cell cytotoxicity. Moreover, raft polarization was inhibited by reagents that disrupt microtubules and actin filaments, whereas synapse formation was not. Thus, NK lipid raft polarization and inhibitory NK immune synapse formation occur by fundamentally distinct mechanisms. PMID:11724921

  7. Reproducible Bioinformatics Research for Biologists

    Science.gov (United States)

    This book chapter describes the current Big Data problem in Bioinformatics and the resulting issues with performing reproducible computational research. The core of the chapter provides guidelines and summaries of current tools/techniques that a noncomputational researcher would need to learn to pe...

  8. Reproducibility of a reaming test

    DEFF Research Database (Denmark)

    Pilny, Lukas; Müller, Pavel; De Chiffre, Leonardo

    2014-01-01

    ). Process reproducibility was assessed as the ability of different operators to ensure a consistent rating of individual lubricants. Absolute average values as well as experimental standard deviations of the evaluation parameters were calculated, and uncertainty budgeting was performed. Results document a...

  9. Reversible and Reproducible Giant Universal Electroresistance Effect

    Institute of Scientific and Technical Information of China (English)

    SYED Rizwan; ZHANG Sen; YU Tian; ZHAO Yong-Gang; ZHANG Shu-Feng; HAN Xiu-Feng

    2011-01-01

    After the prediction of the giant electroresistance effect, much work has been carried out to find this effect in practical devices. We demonstrate a novel way to obtain a large electroresistance (ER) effect in the multilayer system at room temperature. The current-in-plane (CIP) electric transport measurement is performed on the multilayer structure consisting of (011)-Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT)/Ta/Al-O/metal. It is found that the resistance of the top metallic layer shows a hysteretic behavior as a function electric field, which corresponds well with the substrate polarization versus electric Reid (P-E) loop. This reversible hysteretic R-E behavior is independent of the applied magnetic field as well as the magnetic structure of the top metallic layer and keeps its memory state. This novel memory effect is attributed to the polarization reversal induced electrostatic potential, which is felt throughout the multilayer stack and is enhanced by the dielectric Al-O layer producing unique hysteretic, reversible, and reproducible resistance switching behavior. This novel universal electroresistance effect will open a new gateway to the development of future multiferroic memory devices operating at room temperature.%After the prediction of the giant electroresistance effect,much work has been carried out to find this effect in practical devices.We demonstrate a novel way to obtain a large electroresistance (ER) effect in the multilayer system at room temperature.The current-in-plane (CIP) electric transport measurement is performed on the multilayer structure consisting of (011)-Pb(Mg1/3 Nb2/3) O3-PbTiO3 (PMN-PT)/Ta/Al-O/metal.It is found that the resistance of the top metallic layer shows a hysteretic behavior as a function electric field,which corresponds well with the substrate polarization versus electric field (P-E) loop.This reversible hysteretic R-E behavior is independent of the applied magnetic field as well as the magnetic structure of the top metallic

  10. Inter-tissue mechanical stress affects Frizzled-mediated planar cell polarity in the Drosophila notum epidermis

    OpenAIRE

    Olguín, Patricio; Glavic, Alvaro; Mlodzik, Marek

    2011-01-01

    Frizzled/Planar Cell Polarity (Fz/PCP) signaling controls the orientation of sensory bristles and cellular hairs (trichomes) along the antero-posterior axis of the Drosophila thorax (notum) [1–4]. A subset of the trichome-producing notum cells differentiate as “tendon cells”, serving as attachment sites for the indirect flight muscles (IFMs) to the exoskeleton [5]. Through the analysis of chascon (chas), a gene identified by its ability to disrupt Fz/PCP signaling under overexpression conditi...

  11. Human Cytomegalovirus Glycoprotein B Contains Autonomous Determinants for Vectorial Targeting to Apical Membranes of Polarized Epithelial Cells

    OpenAIRE

    Tugizov, Sharof; Maidji, Ekaterina; Xiao, Jianqiao; Zheng, Zhenwei; Pereira, Lenore

    1998-01-01

    We previously reported that human cytomegalovirus (CMV) glycoprotein B (gB) is vectorially transported to apical membranes of CMV-infected polarized human retinal pigment epithelial cells propagated on permeable filter supports and that virions egress predominantly from the apical membrane domain. In the present study, we investigated whether gB itself contains autonomous information for apical transport by expressing the molecule in stably transfected Madine-Darby canine kidney (MDCK) cells ...

  12. Generation of sphingosine-1-phosphate by apoptotic cells and its impact on macrophage polarization in cancer development

    OpenAIRE

    Weigert, Andreas

    2008-01-01

    The removal of apoptotic cells (AC) can be regarded as an integral component of the program to terminate inflammation. Clearance of AC by professional phagocytes such as macrophages induces an anti-inflammatory phenotype in the latter ones. Anti-inflammatory or M2 polarization is also observed in macrophages infiltrating certain human tumors. These tumor-associated macrophages (TAM) contribute actively to tumor progression by promoting immune evasion, angiogenesis and tumor cell survival. The...

  13. Reproducibility of NIF hohlraum measurements

    Science.gov (United States)

    Moody, J. D.; Ralph, J. E.; Turnbull, D. P.; Casey, D. T.; Albert, F.; Bachmann, B. L.; Doeppner, T.; Divol, L.; Grim, G. P.; Hoover, M.; Landen, O. L.; MacGowan, B. J.; Michel, P. A.; Moore, A. S.; Pino, J. E.; Schneider, M. B.; Tipton, R. E.; Smalyuk, V. A.; Strozzi, D. J.; Widmann, K.; Hohenberger, M.

    2015-11-01

    The strategy of experimentally ``tuning'' the implosion in a NIF hohlraum ignition target towards increasing hot-spot pressure, areal density of compressed fuel, and neutron yield relies on a level of experimental reproducibility. We examine the reproducibility of experimental measurements for a collection of 15 identical NIF hohlraum experiments. The measurements include incident laser power, backscattered optical power, x-ray measurements, hot-electron fraction and energy, and target characteristics. We use exact statistics to set 1-sigma confidence levels on the variations in each of the measurements. Of particular interest is the backscatter and laser-induced hot-spot locations on the hohlraum wall. Hohlraum implosion designs typically include variability specifications [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. We describe our findings and compare with the specifications. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  14. Selective and site-specific mobilization of dermal dendritic cells and Langerhans cells by Th1- and Th2-polarizing adjuvants

    OpenAIRE

    Sen, Debasish; Forrest, Luette; Kepler, Thomas B.; Parker, Ian; Cahalan, Michael D.

    2010-01-01

    Dendritic cells (DCs) initiate and polarize adaptive immune responses toward varying functional outcomes. By means of intravital two-photon microscopy, we report that dermal dendritic cells (DDCs) and Langerhans cells (LCs) are differentially mobilized during contact sensitization and by adjuvants such as unmethylated CpG oligonucleotide (CpG) and LPS that induce T helper type 1 (Th1) responses, or papain that induces T helper type 2 (Th2) responses. In ear pinna, contact sensitization, CpG, ...

  15. In vitro Th1 and Th2 cell polarization is severely influenced by the initial ratio of naïve and memory CD4+ T cells

    DEFF Research Database (Denmark)

    Blom, Lars; Poulsen, Lars K.

    even small percentages (99% naïve CD4+ T cells resulted in better Th1 and Th2 polarization with significant reduced fractions of IL-4+ and IFN-γ+ CD4+ T cells, respectively. Moreover, the Th2 primed >99% naïve CD4+ T cells showed significantly higher ratio of IL-4+:IFN-γ+ (>4 fold) and GATA-3:+T...

  16. Analytic performance studies and clinical reproducibility of a real-time PCR assay for the detection of epidermal growth factor receptor gene mutations in formalin-fixed paraffin-embedded tissue specimens of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Epidermal growth factor receptor (EGFR) gene mutations identify patients with non-small cell lung cancer (NSCLC) who have a high likelihood of benefiting from treatment with anti-EGFR tyrosine kinase inhibitors. Sanger sequencing is widely used for mutation detection but can be technically challenging, resulting in longer turn-around-time, with limited sensitivity for low levels of mutations. This manuscript details the technical performance verification studies and external clinical reproducibility studies of the cobas EGFR Mutation Test, a rapid multiplex real-time PCR assay designed to detect 41 mutations in exons 18, 19, 20 and 21. The assay’s limit of detection was determined using 25 formalin-fixed paraffin-embedded tissue (FFPET)-derived and plasmid DNA blends. Assay performance for a panel of 201 specimens was compared against Sanger sequencing with resolution of discordant specimens by quantitative massively parallel pyrosequencing (MPP). Internal and external reproducibility was assessed using specimens tested in duplicate by different operators, using different reagent lots, instruments and at different sites. The effects on the performance of the cobas EGFR test of endogenous substances and nine therapeutic drugs were evaluated in ten FFPET specimens. Other tests included an evaluation of the effects of necrosis, micro-organisms and homologous DNA sequences on assay performance, and the inclusivity of the assay for less frequent mutations. A >95% hit rate was obtained in blends with >5% mutant alleles, as determined by MPP analysis, at a total DNA input of 150 ng. The overall percent agreement between Sanger sequencing and the cobas test was 96.7% (negative percent agreement 97.5%; positive percent agreement 95.8%). Assay repeatability was 98% when tested with two operators, instruments, and reagent lots. In the external reproducibility study, the agreement was > 99% across all sites, all operators and all reagent lots for 11/12 tumors tested. Test

  17. Role of flagella in adherence, internalization, and translocation of Campylobacter jejuni in nonpolarized and polarized epithelial cell cultures.

    Science.gov (United States)

    Grant, C C; Konkel, M E; Cieplak, W; Tompkins, L S

    1993-01-01

    Previous studies of Campylobacter jejuni have suggested that flagellin is an adhesin for epithelial cells and that motility is a virulence factor of this bacterium. The role of flagella in the interactions of C. jejuni with nonpolarized and polarized epithelial cells was examined with flagellar mutants. Flagellated, nonmotile (flaA flaB+ Mot-) and nonflagellated, nonmotile (flaA flaB Mot-) mutants of C. jejuni were constructed by in vivo homologous recombination and gene replacement techniques. Both classes of mutants were found to adhere to cells of human epithelial origin (INT 407) equally well; however, on the basis of the percentage of the inoculum internalized, internalization of the flaA flaB Mot- mutants was decreased by factors ranging from approximately 30 to 40 compared with the parent. The flaA flaB+ Mot- mutant was internalized by the INT 407 cells at levels six- to sevenfold higher than the flaA flaB Mot- mutants. Both classes of mutants, unlike the parent, were unable to translocate across polarized Caco-2 monolayers. These results indicate that flagella are not involved in C. jejuni adherence to epithelial cells but that they do play a role in internalization. Furthermore, the results suggest that either the motility of C. jejuni or the product of flaA is essential for the bacterium to cross polarized epithelial cell monolayers. Images PMID:8478066

  18. Exine dehiscing induces rape microspore polarity, which results in different daughter cell fate and fixes the apical–basal axis of the embryo

    OpenAIRE

    Tang, Xingchun; Liu, Yuan; He, Yuqing; Ma, Ligang; Sun, Meng-xiang

    2012-01-01

    The roles of cell polarity and the first asymmetric cell division during early embryogenesis in apical–basal cell fate determination remain unclear. Previously, a novel Brassica napus microspore embryogenesis system was established, by which rape exine-dehisced microspores were induced by physical stress. Unlike traditional microspore culture, cell polarity and subsequent asymmetric division appeared in the exine-dehisced microspore, which finally developed into a typical embryo with a suspen...

  19. The influence of non polar and polar molecules in mouse motile cells membranes and pure lipid bilayers.

    Directory of Open Access Journals (Sweden)

    Francisco J Sierra-Valdez

    Full Text Available We report an experimental study of mouse sperm motility that shows chief aspects characteristic of neurons: the anesthetic (produced by tetracaine and excitatory (produced by either caffeine or calcium effects and their antagonic action. While tetracaine inhibits sperm motility and caffeine has an excitatory action, the combination of these two substances balance the effects, producing a motility quite similar to that of control cells. We also study the effects of these agents (anesthetic and excitatory on the melting points of pure lipid liposomes constituted by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC and dipalmitoyl phosphatidic acid (DPPA. Tetracaine induces a large fluidization of the membrane, shifting the liposomes melting transition temperature to much lower values. The effect of caffeine is null, but its addition to tetracaine-doped liposomes greatly screen the fluidization effect. A high calcium concentration stiffens pure lipid membranes and strongly reduces the effect of tetracaine. Molecular Dynamics Simulations are performed to further understand our experimental findings at the molecular level. We find a strong correlation between the effect of antagonic molecules that could explain how the mechanical properties suitable for normal cell functioning are affected and recovered.

  20. Improvement the equation of polarization curve of a proton exchange membrane fuel cell at different channel geometry

    Science.gov (United States)

    Khazaee, I.

    2015-12-01

    The polarization curve of a proton exchange membrane fuel cell is an important parameter which is expressed by the change of voltage and current of it that indicates the performance of the cell. The voltage of the cell is a function of temperature that is expressed by the Nernst equation and the equation of voltage losses such as activation loss, ohmic loss and concentration loss. In this study a new correlation for polarization curve is obtained that it in addition to temperature, a new parameter is involved in it that shows the effect of the geometry of cross-section area of channels. For this purpose three PEM fuel cells with different channels geometry of rectangular, elliptical and triangular have constructed. The active area of each cell is 25 cm2 that its weight is 1300 g. The material of the gas diffusion layer is carbon clothes, the membrane is nafion 117 and the catalyst layer is a plane with 0.004 g/cm2 platinum. Also a test bench designed and constructed for testing the cell and a series of experiments are carried out to investigate the influence of the geometry of the cell on performance of the cell. The results show that when the geometry of channel is rectangular the performance of the cell is better than the triangular and elliptical channel.

  1. Cu₂ZnSnS(4x)Se(4(1-x)) solar cells from polar nanocrystal inks.

    Science.gov (United States)

    van Embden, Joel; Chesman, Anthony S R; Della Gaspera, Enrico; Duffy, Noel W; Watkins, Scott E; Jasieniak, Jacek J

    2014-04-01

    A facile ligand exchange method for dispersing Cu2ZnSnS4 (CZTS) nanocrystals (NCs) in environmentally benign polar solvents, such as ethanol or n-propanol, at high concentrations (up to 200 mg/mL) is demonstrated. This approach has been applied to CZTS nanocrystals synthesized via scalable, noninjection methods to formulate colloidally stable inks that are suitable for the solution processing of solar cell devices. Unlike other inks currently used to fabricate NC solar cells, the CZTS nanocrystal ink developed here circumvents the need for hydrazine, pyridine, or thiol coordinating solvents. By combining our polar CZTS inks with optimized selenization procedures, substrate CZTSSe solar cells have been successfully fabricated with device efficiencies of 7.7%. PMID:24690032

  2. Synchrotron radiation X-ray microfluorescence reveals polarized distribution of atomic elements during differentiation of pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Simone C Cardoso

    Full Text Available The mechanisms underlying pluripotency and differentiation in embryonic and reprogrammed stem cells are unclear. In this work, we characterized the pluripotent state towards neural differentiated state through analysis of trace elements distribution using the Synchrotron Radiation X-ray Fluorescence Spectroscopy. Naive and neural-stimulated embryoid bodies (EB derived from embryonic and induced pluripotent stem (ES and iPS cells were irradiated with a spatial resolution of 20 µm to make elemental maps and qualitative chemical analyses. Results show that these embryo-like aggregates exhibit self-organization at the atomic level. Metallic elements content rises and consistent elemental polarization pattern of P and S in both mouse and human pluripotent stem cells were observed, indicating that neural differentiation and elemental polarization are strongly correlated.

  3. Autofocus Correction of Azimuth Phase Error and Residual Range Cell Migration in Spotlight SAR Polar Format Imagery

    CERN Document Server

    Mao, Xinhua; Zhu, Zhaoda

    2012-01-01

    Synthetic aperture radar (SAR) images are often blurred by phase perturbations induced by uncompensated sensor motion and /or unknown propagation effects caused by turbulent media. To get refocused images, autofocus proves to be useful post-processing technique applied to estimate and compensate the unknown phase errors. However, a severe drawback of the conventional autofocus algorithms is that they are only capable of removing one-dimensional azimuth phase errors (APE). As the resolution becomes finer, residual range cell migration (RCM), which makes the defocus inherently two-dimensional, becomes a new challenge. In this paper, correction of APE and residual RCM are presented in the framework of polar format algorithm (PFA). First, an insight into the underlying mathematical mechanism of polar reformatting is presented. Then based on this new formulation, the effect of polar reformatting on the uncompensated APE and residual RCM is investigated in detail. By using the derived analytical relationship betwee...

  4. Intracellular photoreceptive site for blue light-induced cell division in protonemata of the fern Adiantum [Pteridophyta]: Further analyses by polarized light irradiation and cell centrifugation

    International Nuclear Information System (INIS)

    The intracellular localization of the photoreceptive site for blue light-induced cell division in single-celled protonemata of Adiantum capillus-veneris L. was investigated using polarized light irradiation and protonemal cell centrifugation. The response to irradiation with polarized blue light showed no dependence on the direction of light polarization. However, centrifugation of the protonemata followed by microbeam irradiation showed that the site of blue light perception could be displaced together with the nucleus. Centrifugal treatment changed the distribution of intracellular organelles at the time of light exposure and basipetally displaced the nucleus about 90μm. This treatment had no effect on the induction of cell division with blue light if the protonemata were centrifuged again acropetally after the light treatment. Microbeam (30×30 μm2) irradiation with blue light of the apical 45–75 βm region, the receptive site of blue light in non-centrifuged cell, did not induce cell division. However, cell division was induced by irradiation of the nucleus-containing region, indicating that the photoreceptive site was displaced together with the nucleus by the centrifugation. These results suggest that the blue light receptor regulating cell division in Adiantum protonemata is not likely to be located on the plasma membrane. (author)

  5. Polyfluorene Electrolytes Interfacial Layer for Efficient Polymer Solar Cells: Controllably Interfacial Dipoles by Regulation of Polar Groups.

    Science.gov (United States)

    Liu, Huimin; Hu, Lin; Wu, Feiyan; Chen, Lie; Chen, Yiwang

    2016-04-20

    The polar groups in the conjugated polyelectrolytes (CPEs) can create the favorable dipoles at the electrode/active layer interface, which is critical for the CPEs to minimize the interfacial energy barrier in polymer solar cells (PSCs). Herein, a series of CPEs based on poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-co-2,7-(9,9-dioctylfluorene)] derivates (PFNs) (PFN30, PFN50, PFN70, and PFN100) with different mole ratio of polar groups (-N(C2H5)2) were designed and synthesized to investigate the effect of the numbers of polar groups on the interfacial dipoles. Controllably interfacial dipoles could be readily achieved by only tuning the numbers of -N(C2H5)2 in PFNs, as revealed by the work function of the PFNs modified ITO gradually reduced as the loadings of the -N(C2H5)2 increased. In addition, increasing the numbers of -N(C2H5)2 in PFNs were also favorable for developing the smooth and homogeneous morphology of the active layer. As a result, the content of the polar amine in the PFNs exerted great influence on the performance of polymer solar cells. Increasing the numbers of the pendent -N(C2H5)2 could effectively improve the power conversion efficiency (PCE) of the devices. Among these PFNs, PFN100 with the highest content of -N(C2H5)2 polar groups delivered the device with the best PCE of 3.27%. It indicates tailoring the content of the polar groups in the CPEs interlayer is a facial and promising approach for interfacial engineering to developing high performance PSCs. PMID:27028166

  6. Development a new equation of polarization curve for a proton exchange membrane fuel cell at different channel geometry

    Directory of Open Access Journals (Sweden)

    I. Khazaee

    2014-01-01

    Full Text Available The polarization curve of a proton exchange membrane fuel cell is an important parameter that is used to investigate the performance of it that is expressed with the Nernst equation with the equation of losses the voltage such as activation loss, ohmic loss and concentration loss that they are a function of temperature of the cell and the current density. In this study a new correlation for polarization curve is obtained that it is a function of temperature, current density and a new parameter of cross-section geometry of channels. For this purpose three PEM fuel cells with different channels geometry of rectangular, elliptical and triangular have constructed. The active area of each cell is that its weight is 1300gr. The material of the gas diffusion layer is Carbon clothes, the membrane is nafion112 and the catalyst layer is a plane with 0.004 gr/cm2 Platinum. Also a test bench designed and constructed for testing the cell and a series of experiments are carried out to investigate the influence of the geometry of the cell on performance of the cell. The results show that when the geometry of channel is rectangular the performance of the cell is better than the triangular and elliptical channel.

  7. Bipolar switching polarity reversal by electrolyte layer sequence in electrochemical metallization cells with dual-layer solid electrolytes.

    Science.gov (United States)

    Soni, Rohit; Meuffels, Paul; Petraru, Adrian; Hansen, Mirko; Ziegler, Martin; Vavra, Ondrej; Kohlstedt, Hermann; Jeong, Doo Seok

    2013-12-21

    Bipolar switching behaviours of electrochemical metallization (ECM) cells with dual-layer solid electrolytes (SiOx-Ge0.3Se0.7) were analyzed. Type 1 ECM cell, Pt (bottom electrode)/SiOx/Ge0.3Se0.7/Cu (top electrode), exhibited typical eightwise current-voltage (I-V) hysteresis of ECM cells whereas Type 2 ECM cell, Pt (bottom electrode)/Ge0.3Se0.7/SiOx/Cu(top electrode), showed counter-eightwise hysteresis. In addition, absolute off-switching voltage in Type 2 cell is lower than that in Type 1 cell while on-switching voltage in both cells is almost the same. An attempt to understand this electrolyte-stack-sequence-depending switching polarity reversal was made in terms of the ECM cell potential change upon the electrolyte stack sequence and the consequent change in Cu filament growth direction. Relevant experimental evidence for the hypothesis was obtained regarding the switching behaviours. Furthermore, given the switching polarity reversal, feasibility of serial complementary resistive switches was also demonstrated. PMID:24177268

  8. [Adipose-derived stem cells promote the polarization from M1 macrophages to M2 macrophages].

    Science.gov (United States)

    Yin, Xuehong; Pang, Chunyan; Bai, Li; Zhang, Ying; Geng, Lixia

    2016-03-01

    Objective To investigate the effects of adipose-derived stem cells (ADSCs) on M1/M2 macrophages and whether ADSCs are able to promote the polarization from M1 macrophages to M2 macrophages. Methods M1 macrophages were induced from J774.1 macrophages by 24-hour stimulation of lipopolysaccharide (LPS) and interferon γ (IFN-γ), and M2 macrophages were induced from J774.1 macrophages by interleukin 4 (IL-4) for another 24 hours. Then M1/M2 macrophages were separately cultured in the presence of ADSCs for 24 hours. The M1/M2 macrophages and their corresponding supernatants were collected for further analysis. The expressions of IL-6, tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS), CC chemokine ligand 2 (CCL2), CD86, arginase 1 (Arg1), mannose receptors/CD206 (MR/CD206), IL-10, found in inflammatory zone 1 (FIZZ1), chitinase 3-like 3 (Ym-1) were detected by real-time PCR and ELISA. Results ADSCs significantly decreased the levels of IL-6, TNF-α, iNOS, CCL2 and CD86, and increased the levels of Arg1, CD206 and IL-10 in M1 macrophages. In the supernatant of M1 macrophages, the expressions of IL-6 and TNF-α were reduced, while those of CD206 were enhanced. In M2 macrophages, ADSCs resulted in down-regulation of IL-6, TNF-α, iNOS, CD86 and up-regulation of Arg1, CD206, FIZZ-1, Ym-1 and IL-10. In the supernatant of M2 macrophages, the expression levels of IL-6 and TNF-α were down-regulated and those of CD206 were up-regulated. Conclusion ADSCs can inhibit the gene expression of M1 macrophages and promote the gene expression of M2 macrophages, as well as mediate the polarization from M1 macrophages to M2 macrophages. PMID:26927552

  9. Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice▿

    Science.gov (United States)

    Meisinger-Henschel, Christine; Späth, Michaela; Lukassen, Susanne; Wolferstätter, Michael; Kachelriess, Heike; Baur, Karen; Dirmeier, Ulrike; Wagner, Markus; Chaplin, Paul; Suter, Mark; Hausmann, Jürgen

    2010-01-01

    Modified vaccinia virus Ankara (MVA) has a highly restricted host range in cell culture and is apathogenic in vivo. MVA was derived from the parental chorioallantois vaccinia virus Ankara (CVA) by more than 570 passages in chicken embryo fibroblast (CEF) cells. During CEF cell passaging, six major deletions comprising 24,668 nucleotides occurred in the CVA genome. We have cloned both the MVA and the parental CVA genome as bacterial artificial chromosomes (BACs) and have sequentially introduced the six major MVA deletions into the cloned CVA genome. Reconstituted mutant CVA viruses containing up to six major MVA deletions showed no detectable replication restriction in 12 of 14 mammalian cell lines tested; the exceptions were rabbit cell lines RK13 and SIRC. In mice, CVA mutants with up to three deletions showed slightly enhanced virulence, suggesting that gene deletion in replicating vaccinia virus (VACV) can result in gain of fitness in vivo. CVA mutants containing five or all six deletions were still pathogenic, with a moderate degree of attenuation. Deletion V was mainly responsible for the attenuated phenotype of these mutants. In conclusion, loss or truncation of all 31 open reading frames in the six major deletions is not sufficient to reproduce the specific MVA phenotype of strong attenuation and highly restricted host range. Mutations in viral genes outside or in association with the six major deletions appear to contribute significantly to this phenotype. Host range restriction and avirulence of MVA are most likely a cooperative effect of gene deletions and mutations involving the major deletions. PMID:20668072

  10. Introduction of the six major genomic deletions of modified vaccinia virus Ankara (MVA) into the parental vaccinia virus is not sufficient to reproduce an MVA-like phenotype in cell culture and in mice.

    Science.gov (United States)

    Meisinger-Henschel, Christine; Späth, Michaela; Lukassen, Susanne; Wolferstätter, Michael; Kachelriess, Heike; Baur, Karen; Dirmeier, Ulrike; Wagner, Markus; Chaplin, Paul; Suter, Mark; Hausmann, Jürgen

    2010-10-01

    Modified vaccinia virus Ankara (MVA) has a highly restricted host range in cell culture and is apathogenic in vivo. MVA was derived from the parental chorioallantois vaccinia virus Ankara (CVA) by more than 570 passages in chicken embryo fibroblast (CEF) cells. During CEF cell passaging, six major deletions comprising 24,668 nucleotides occurred in the CVA genome. We have cloned both the MVA and the parental CVA genome as bacterial artificial chromosomes (BACs) and have sequentially introduced the six major MVA deletions into the cloned CVA genome. Reconstituted mutant CVA viruses containing up to six major MVA deletions showed no detectable replication restriction in 12 of 14 mammalian cell lines tested; the exceptions were rabbit cell lines RK13 and SIRC. In mice, CVA mutants with up to three deletions showed slightly enhanced virulence, suggesting that gene deletion in replicating vaccinia virus (VACV) can result in gain of fitness in vivo. CVA mutants containing five or all six deletions were still pathogenic, with a moderate degree of attenuation. Deletion V was mainly responsible for the attenuated phenotype of these mutants. In conclusion, loss or truncation of all 31 open reading frames in the six major deletions is not sufficient to reproduce the specific MVA phenotype of strong attenuation and highly restricted host range. Mutations in viral genes outside or in association with the six major deletions appear to contribute significantly to this phenotype. Host range restriction and avirulence of MVA are most likely a cooperative effect of gene deletions and mutations involving the major deletions. PMID:20668072

  11. Dependence of InGaN solar cell performance on polarization-induced electric field and carrier lifetime

    International Nuclear Information System (INIS)

    The effects of Mg-induced net acceptor doping concentration and carrier lifetime on the performance of a p—i—n InGaN solar cell are investigated. It is found that the electric field induced by spontaneous and piezoelectric polarization in the i-region could be totally shielded when the Mg-induced net acceptor doping concentration is sufficiently high. The polarization-induced potential barriers are reduced and the short circuit current density is remarkably increased from 0.21 mA/cm2 to 0.95 mA/cm2 by elevating the Mg doping concentration. The carrier lifetime determined by defect density of i-InGaN also plays an important role in determining the photovoltaic properties of solar cell. The short circuit current density severely degrades, and the performance of InGaN solar cell becomes more sensitive to the polarization when carrier lifetime is lower than the transit time. This study demonstrates that the crystal quality of InGaN absorption layer is one of the most important challenges in realizing high efficiency InGaN solar cells. (interdisciplinary physics and related areas of science and technology)

  12. Blazed vector grating liquid crystal cells with photocrosslinkable polymeric alignment films fabricated by one-step polarizer rotation method

    Science.gov (United States)

    Kawai, Kotaro; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2014-12-01

    Blazed vector grating liquid crystal (LC) cells, in which the directors of low-molar-mass LCs are antisymmetrically distributed, were fabricated by one-step exposure of an empty glass cell inner-coated with a photocrosslinkable polymer LC (PCLC) to UV light. By adopting a LC cell structure, twisted nematic (TN) and homogeneous (HOMO) alignments were obtained in the blazed vector grating LC cells. Moreover, the diffraction efficiency of the blazed vector grating LC cells was greatly improved by increasing the thickness of the device in comparison with that of a blazed vector grating with a thin film structure obtained in our previous study. In addition, the diffraction efficiency and polarization states of ±1st-order diffracted beams from the resultant blazed vector grating LC cells were controlled by designing a blazed pattern in the alignment films, and these diffraction properties were well explained on the basis of Jones calculus and the elastic continuum theory of nematic LCs.

  13. Increased malignancy of oral squamous cell carcinomas (oscc) is associated with macrophage polarization in regional lymph nodes – an immunohistochemical study

    OpenAIRE

    Wehrhan, Falk; Büttner-Herold, Maike; Hyckel, Peter; Moebius, Patrick; Preidl, Raimund; Distel, Luitpold; Ries, Jutta; Amann, Kerstin; Schmitt, Christian; Neukam, Friedrich W.; Weber, Manuel

    2014-01-01

    Background It is largely accepted that specific immunological parameters in solid malignancies are associated with patient’s prognosis. Recently a correlation of macrophage polarization with histomorphological parameters could also be shown in oral squamous cell carcinoma (oscc). The observed tumor derived peripheral immune tolerance could be associated with the macrophage polarization in regional tumor draining lymph nodes. So far there are no studies analyzing the macrophage polarization in...

  14. Expression and subcellular localization of aquaporin water channels in the polarized hepatocyte cell line, WIF-B

    Directory of Open Access Journals (Sweden)

    Marinelli Raúl A

    2005-08-01

    Full Text Available Abstract Background Recent data suggest that canalicular bile secretion involves selective expression and coordinated regulation of aquaporins (AQPs, a family of water channels proteins. In order to further characterize the role of AQPs in this process, an in vitro cell system with retained polarity and expression of AQPs and relevant solute transporters involved in bile formation is highly desirable. The WIF-B cell line is a highly differentiated and polarized rat hepatoma/human fibroblast hybrid, which forms abundant bile canalicular structures. This cell line has been reported to be a good in vitro model for studying hepatocyte polarity. Results Using RT-PCR, immunoblotting and confocal immunofluorescence, we showed that WIF-B cells express the aquaporin water channels that facilitate the osmotically driven water movements in the liver, i.e. AQP8, AQP9, and AQP0; as well as the key solute transporters involved in the generation of canalicular osmotic gradients, i.e., the bile salt export pump Bsep, the organic anion transporter Mrp2 and the chloride bicarbonate exchanger AE2. The subcellular localization of the AQPs and the solute transporters in WIF-B cells was similar to that in freshly isolated rat hepatocytes and in intact liver. Immunofluorescent costaining studies showed intracellular colocalization of AQP8 and AE2, suggesting the possibility that these transporters are expressed in the same population of pericanalicular vesicles. Conclusion The hepatocyte cell line WIF-B retains the expression and subcellular localization of aquaporin water channels as well as key solute transporters for canalicular bile secretion. Thus, these cells can work as a valuable tool for regulatory and mechanistic studies of the biology of bile formation.

  15. Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays

    Science.gov (United States)

    Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

    2015-07-01

    We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.

  16. Evaluation of multichannel reproduced sound

    DEFF Research Database (Denmark)

    Choisel, Sylvain; Wickelmaier, Florian Maria

    2007-01-01

    A study was conducted with the goal of quantifying auditory attributes which underlie listener preference for multichannel reproduced sound. Short musical excerpts were presented in mono, stereo and several multichannel formats to a panel of forty selected listeners. Scaling of auditory attributes......, as well as overall preference, was based on consistency tests of binary paired-comparison judgments and on modeling the choice frequencies using probabilistic choice models. As a result, the preferences of non-expert listeners could be measured reliably at a ratio scale level. Principal components...... derived from the quantified attributes predict overall preference well. The findings allow for some generalizations within musical program genres regarding the perception of and preference for certain spatial reproduction modes, but for limited generalizations across selections from different musical...

  17. Wdpcp, a PCP protein required for ciliogenesis, regulates directional cell migration and cell polarity by direct modulation of the actin cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Cheng Cui

    2013-11-01

    Full Text Available Planar cell polarity (PCP regulates cell alignment required for collective cell movement during embryonic development. This requires PCP/PCP effector proteins, some of which also play essential roles in ciliogenesis, highlighting the long-standing question of the role of the cilium in PCP. Wdpcp, a PCP effector, was recently shown to regulate both ciliogenesis and collective cell movement, but the underlying mechanism is unknown. Here we show Wdpcp can regulate PCP by direct modulation of the actin cytoskeleton. These studies were made possible by recovery of a Wdpcp mutant mouse model. Wdpcp-deficient mice exhibit phenotypes reminiscent of Bardet-Biedl/Meckel-Gruber ciliopathy syndromes, including cardiac outflow tract and cochlea defects associated with PCP perturbation. We observed Wdpcp is localized to the transition zone, and in Wdpcp-deficient cells, Sept2, Nphp1, and Mks1 were lost from the transition zone, indicating Wdpcp is required for recruitment of proteins essential for ciliogenesis. Wdpcp is also found in the cytoplasm, where it is localized in the actin cytoskeleton and in focal adhesions. Wdpcp interacts with Sept2 and is colocalized with Sept2 in actin filaments, but in Wdpcp-deficient cells, Sept2 was lost from the actin cytoskeleton, suggesting Wdpcp is required for Sept2 recruitment to actin filaments. Significantly, organization of the actin filaments and focal contacts were markedly changed in Wdpcp-deficient cells. This was associated with decreased membrane ruffling, failure to establish cell polarity, and loss of directional cell migration. These results suggest the PCP defects in Wdpcp mutants are not caused by loss of cilia, but by direct disruption of the actin cytoskeleton. Consistent with this, Wdpcp mutant cochlea has normal kinocilia and yet exhibits PCP defects. Together, these findings provide the first evidence, to our knowledge, that a PCP component required for ciliogenesis can directly modulate the actin

  18. Study in static mode of a photovoltaic cell bi facial to crystalline silicon under electric polarization and constant multispectral illumination

    International Nuclear Information System (INIS)

    The theoretical study in static mode of a photovoltaic cell bi facial to silicon under electric polarization and multispectral illumination is presented. Through this study, various expressions of the parameters of recombination have been established as well for an illumination by the face before an illumination by the back face. Curves of variation of the densities of carriers, densities of photocurrent, speeds of recombinations and photo tensions have been traced for the two modes of illumination

  19. Genetic interactions between planar cell polarity genes cause diverse neural tube defects in mice.

    Science.gov (United States)

    Murdoch, Jennifer N; Damrau, Christine; Paudyal, Anju; Bogani, Debora; Wells, Sara; Greene, Nicholas D E; Stanier, Philip; Copp, Andrew J

    2014-10-01

    Neural tube defects (NTDs) are among the commonest and most severe forms of developmental defect, characterized by disruption of the early embryonic events of central nervous system formation. NTDs have long been known to exhibit a strong genetic dependence, yet the identity of the genetic determinants remains largely undiscovered. Initiation of neural tube closure is disrupted in mice homozygous for mutations in planar cell polarity (PCP) pathway genes, providing a strong link between NTDs and PCP signaling. Recently, missense gene variants have been identified in PCP genes in humans with NTDs, although the range of phenotypes is greater than in the mouse mutants. In addition, the sequence variants detected in affected humans are heterozygous, and can often be detected in unaffected individuals. It has been suggested that interactions between multiple heterozygous gene mutations cause the NTDs in humans. To determine the phenotypes produced in double heterozygotes, we bred mice with all three pairwise combinations of Vangl2(Lp), Scrib(Crc) and Celsr1(Crsh) mutations, the most intensively studied PCP mutants. The majority of double-mutant embryos had open NTDs, with the range of phenotypes including anencephaly and spina bifida, therefore reflecting the defects observed in humans. Strikingly, even on a uniform genetic background, variability in the penetrance and severity of the mutant phenotypes was observed between the different double-heterozygote combinations. Phenotypically, Celsr1(Crsh);Vangl2(Lp);Scrib(Crc) triply heterozygous mutants were no more severe than doubly heterozygous or singly homozygous mutants. We propose that some of the variation between double-mutant phenotypes could be attributed to the nature of the protein disruption in each allele: whereas Scrib(Crc) is a null mutant and produces no Scrib protein, Celsr1(Crsh) and Vangl2(Lp) homozygotes both express mutant proteins, consistent with dominant effects. The variable outcomes of these genetic

  20. Improved polarization of mesoporous electrodes of a proton exchange membrane fuel cell using N-methyl-2-pyrrolidinone

    International Nuclear Information System (INIS)

    Highlights: • Enhancement of decal-transfer rate by controlling hydrophilicity of the CL. • Well-distributed CL microstructures by using NMP-containing ink. • Improved cell polarization by achieving highly connected Pt/C agglomerates. • Effect of different solvents on the electrochemical performance of the CL. -- Abstract: Both the catalytic and ohmic polarization of a proton exchange membrane fuel cell must be improved to achieve commercialization. Herein, high-performance membrane electrode assemblies (MEAs) were prepared using an amide-type chemical, i.e., N-methyl-2-pyrrolidinone (NMP) as a solvent for the catalyst ink. Influence of different solvent on the catalyst-layer (CL) surface microstructure was clarified to achieve high fuel-cell performance. The electrochemical performance of the MEAs made from different ink formulation was examined in detail using electrochemical impedance spectroscopy and cyclic voltammetry. As a result, the NMP–glycerol ink with a 10 wt.% glycerol was used to form a dense and well-connected Pt/C–Nafion agglomerated CL, followed by enhanced catalytic and ohmic polarizations relative to the glycerol and NMP CLs

  1. Polarization Imaging Apparatus for Cell and Tissue Imaging and Diagnostics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In recent years there has been an increasing interest in the propagation of polarized light in randomly scattering media. The investigation of backscattered light...

  2. Polarization Imaging Apparatus for Cell and Tissue Imaging and Diagnostics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This work proposes to capitalize on our Phase I success in a novel visible-near infrared Stokes polarization imaging technology based on high performance fast...

  3. Expression of the human immunodeficiency virus envelope glycoprotein is restricted to basolateral surfaces of polarized epithelial cells

    International Nuclear Information System (INIS)

    Polarized epithelial cells exhibit apical (lumenal) and basolateral (serosal) membrane domains that are separated by circumferential tight junctions. In such cells, enveloped viruses that mature by budding at cell surfaces are released at particular membrane domains. The authors have used a vaccinia virus recombinant to investigate the site of surface expression of the human immunodeficiency virus type 1 envelope glycoprotein in Madin-Darby canine kidney cells. Cells were infected with the vaccinia virus recombinant, and surface expression of the glycoprotein was analyzed by indirect immunofluorescence, 125I-protein A binding, and immunoelectron microscopy. The glycoprotein appeared exclusively at the basolateral surface as early as 2 h postinfection and reached a maximum level at 8 h postinfection. The gp120 glycoprotein was found to be secreted efficiently into culture medium, and this secretion occurred exclusively at the basolateral surface

  4. A polarization-independent liquid crystal phase modulation using polymer-network liquid crystals in a 90° twisted cell

    Science.gov (United States)

    Lin, Yi-Hsin; Chen, Ming-Syuan; Lin, Wei-Chih; Tsou, Yu-Shih

    2012-07-01

    A polarization-independent liquid crystal phase modulation using polymer-network liquid crystals in a 90° twisted cell (T-PNLC) is demonstrated. T-PNLC consists of three layers. Liquid crystal (LC) directors in the two layers near glass substrates are orthogonal to each other and those two layers modulate two eigen-polarizations of an incident light. As a result, two eigen-polarizations of an incident light experience the same phase shift. In the middle layer, LC directors are perpendicular to the glass substrate and contribute no phase shift. The phase shift of T-PNLC is electrically tunable and polarization-independent. T-PNLC does not require any bias voltage for operation. The phase shift is 0.28 π rad for the voltage of 30 Vrms. By measuring and analyzing the optical phase shift of T-PNLC at the oblique incidence of transverse magnetic wave, the pretilt angle of LC directors and the effective thickness of three layers are obtained and discussed. The potential applications are spatial light modulators, laser beam steering, and micro-lens arrays.

  5. Extracellular enzymatic activities of cold-adapted bacteria from polar oceans and effect of temperature and salinity on cell growth

    Institute of Scientific and Technical Information of China (English)

    Zeng Yinxin; Yu Yong; Chen Bo; Li Huirong

    2004-01-01

    The potential of 324 bacteria isolated from different habitats in polar oceans to produce a variety of extracellular enzymatic activities at low temperature was investigated. By plate assay, lipase, protease, amylase, gelatinase, agarase, chitinase or cellulase were detected. Lipases were generally present by bacteria living in polar oceans. Protease-producing bacteria held the second highest proportion in culturable isolates. Strains producing amylase kept a relative stable proportion of around 30% in different polar marine habitats. All 50 Arctic sea-ice bacteria producing proteases were cold-adapted strains, however, only 20% were psychrophilic. 98% of them could grow at 3% NaCl, and 56% could grow without NaCl. On the other hand, 98% of these sea-ice bacteria produced extracellular proteases with optimum temperature at or higher than 35℃, well above the upper temperature limit of cell growth. Extracellular enzymes including amylase, agarase, cellulase and lipase released by bacteria from seawater or sediment in polar oceans, most expressed maximum activities between 25 and 35℃. Among extracellular enzymes released by bacterial strain BSw20308, protease expressed maximum activity at 40℃, higher than 35℃ of polysaccharide hydrolases and 25℃ of lipase.

  6. Compact Circularly Polarized Patch Antenna Using a Composite Right/Left-Handed Transmission Line Unit-Cell

    OpenAIRE

    Geng, L.; Wang, G. M.; Zhang, C. X.; Gao, X. J.; Zong, B. F.

    2013-01-01

    A compact circularly polarized (CP) patch antenna using a composite right/left-handed (CRLH) transmission line (TL) unit-cell is proposed. The CRLH TL unit-cell includes a complementary split ring resonator (CSRR) for shunt inductance and a gap loaded with a circular-shaped slot for series capacitance. The CSRR can decrease the TM10 mode resonance frequency, thus reducing the electrical size of the proposed antenna. In addition, the asymmetry of the CSRR brings about the TM01 mode, which can ...

  7. Evaluation of Extraction Protocols for Simultaneous Polar and Non-Polar Yeast Metabolite Analysis Using Multivariate Projection Methods

    Directory of Open Access Journals (Sweden)

    Nicolas P. Tambellini

    2013-07-01

    Full Text Available Metabolomic and lipidomic approaches aim to measure metabolites or lipids in the cell. Metabolite extraction is a key step in obtaining useful and reliable data for successful metabolite studies. Significant efforts have been made to identify the optimal extraction protocol for various platforms and biological systems, for both polar and non-polar metabolites. Here we report an approach utilizing chemoinformatics for systematic comparison of protocols to extract both from a single sample of the model yeast organism Saccharomyces cerevisiae. Three chloroform/methanol/water partitioning based extraction protocols found in literature were evaluated for their effectiveness at reproducibly extracting both polar and non-polar metabolites. Fatty acid methyl esters and methoxyamine/trimethylsilyl derivatized aqueous compounds were analyzed by gas chromatography mass spectrometry to evaluate non-polar or polar metabolite analysis. The comparative breadth and amount of recovered metabolites was evaluated using multivariate projection methods. This approach identified an optimal protocol consisting of 64 identified polar metabolites from 105 ion hits and 12 fatty acids recovered, and will potentially attenuate the error and variation associated with combining metabolite profiles from different samples for untargeted analysis with both polar and non-polar analytes. It also confirmed the value of using multivariate projection methods to compare established extraction protocols.

  8. Hybrid cell lines constitute a potential reservoir of polarized cells: isolation and study of highly differentiated hepatoma-derived hybrid cells able to form functional bile canaliculi in vitro

    OpenAIRE

    1991-01-01

    A large number of hepatoma cell lines has been used to study expression and regulation of liver-specific function. However these cells, even the most differentiated, are morphologically far from hepatocytes. In no case is the typical hepatocyte cell polarity well maintained. Cell hybridization has been used as a potential means for turning on specific genes. From hybrids between well differentiated Fao rat hepatoma cells and WI 38 human fibroblasts, we have attempted to isolate segregated cel...

  9. Water-polysaccharide interactions in the primary cell wall of Arabidopsis thaliana from polarization transfer solid-state NMR.

    Science.gov (United States)

    White, Paul B; Wang, Tuo; Park, Yong Bum; Cosgrove, Daniel J; Hong, Mei

    2014-07-23

    Polysaccharide-rich plant cell walls are hydrated under functional conditions, but the molecular interactions between water and polysaccharides in the wall have not been investigated. In this work, we employ polarization transfer solid-state NMR techniques to study the hydration of primary-wall polysaccharides of the model plant, Arabidopsis thaliana. By transferring water (1)H polarization to polysaccharides through distance- and mobility-dependent (1)H-(1)H dipolar couplings and detecting it through polysaccharide (13)C signals, we obtain information about water proximity to cellulose, hemicellulose, and pectins as well as water mobility. Both intact and partially extracted cell wall samples are studied. Our results show that water-pectin polarization transfer is much faster than water-cellulose polarization transfer in all samples, but the extent of extraction has a profound impact on the water-polysaccharide spin diffusion. Removal of calcium ions and the consequent extraction of homogalacturonan (HG) significantly slowed down spin diffusion, while further extraction of matrix polysaccharides restored the spin diffusion rate. These trends are observed in cell walls with similar water content, thus they reflect inherent differences in the mobility and spatial distribution of water. Combined with quantitative analysis of the polysaccharide contents, our results indicate that calcium ions and HG gelation increase the amount of bound water, which facilitates spin diffusion, while calcium removal disrupts the gel and gives rise to highly dynamic water, which slows down spin diffusion. The recovery of spin diffusion rates after more extensive extraction is attributed to increased water-exposed surface areas of the polysaccharides. Water-pectin spin diffusion precedes water-cellulose spin diffusion, lending support to the single-network model of plant primary walls in which a substantial fraction of the cellulose surface is surrounded by pectins. PMID:24984197

  10. Localization of Core Planar Cell Polarity Proteins, PRICKLEs, in Ameloblasts of Rat Incisors: Possible Regulation of Enamel Rod Decussation

    International Nuclear Information System (INIS)

    To confirm the possible involvement of planar cell polarity proteins in odontogenesis, one group of core proteins, PRICKLE1, PRICKLE2, PRICKLE3, and PRICKLE4, was examined in enamel epithelial cells and ameloblasts by immunofluorescence microscopy. PRICKLE1 and PRICKLE2 showed similar localization in the proliferation and secretory zones of the incisor. Immunoreactive dots and short rods in ameloblasts and stratum intermedium cells were evident in the proliferation to differentiation zone, but in the secretion zone, cytoplasmic dots decreased and the distal terminal web was positive for PRICKLE1 and PRICKLE2. PRICKLE3 and PRICKLE4 showed cytoplasmic labeling in ameloblasts and other enamel epithelial cells. Double labeling of PRICKLE2 with VANGL1, which is another planar cell polarity protein, showed partial co-localization. To examine the transport route of PRICKLE proteins, PRICKLE1 localization was examined after injection of a microtubule-disrupting reagent, colchicine, and was compared with CX43, which is a membrane protein transported as vesicles via microtubules. The results confirmed the retention of immunoreactive dots for PRICKLE1 in the cytoplasm of secretory ameloblasts of colchicine-injected animals, but fewer dots were observed in control animals. These results suggest that PRICKLE1 and PRICKLE2 are transported as vesicles to the junctional area, and are involved in pattern formation of distal junctional complexes and terminal webs of ameloblasts, further implying a role in the formed enamel rod arrangement

  11. Influence of carbon support microstructure on the polarization behavior of a polymer electrolyte membrane fuel cell membrane electrode assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Guha, Abhishek; Schiraldi, David A. [Department of Macromolecular Science and Engineering and Case Advanced Power Institute, Case Western Reserve University, 10900 Euclid Avenue, 2100 Adelbert Rd, Cleveland, OH 44106-7202 (United States); Zawodzinski, Thomas A. Jr. [Department of Chemical Engineering and Case Advanced Power Institute, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States)

    2010-08-15

    The influence of carbon support morphology on the polarization behavior of a PEM fuel cell membrane electrode assembly has been investigated in this communication. Nanometer sized platinum electrocatalyst particles were deposited on lower surface area fibrous (carbon nanofibers) and particulate carbon supports (carbon blacks) by the well-documented ethylene glycol route for supported electrocatalyst synthesis. These supported catalyst systems were subsequently utilized to prepare catalyst inks and membrane electrode assemblies (MEA) in conjunction with a perflurosulfonated ionomeric membrane-Nafion {sup registered}. Level of liquid Nafion binder in the supported catalyst inks was varied and the ramifications of such a variation on polarization behavior of the MEA determined. The trend in polarization performance was found to be independent of the carbon support morphology in the various ink compositions. The two varieties of carbon supports were also mixed together in various weight ratios and platinum was deposited by the glycol method. Key parameters such as the platinum content on carbon and platinum particle size were determined to be independent of the nature of the supports on which the particles had been deposited. The results indicate that lower surface area carbon supports of vastly contrasting morphologies can be interchangeably employed as catalyst support materials in a PEM fuel cell MEA. (author)

  12. Distribution specificity of polarized populations of T helper cells in patients with chronic hepatitis B virus infection

    Institute of Scientific and Technical Information of China (English)

    JIANG Rong-long; FENG Xiao-rong; LU Qiao-sheng; LUO Kang-xian; FU Ning

    2001-01-01

    Objective: To investigate the roles of the polarized populations of T helper cells isolated from the peripheral blood mononuclear cells (PBMCs) of individuals with chronic hepatitis B virus (HBV) infection. Methods: PBMCs from patients with chronic HBV infection were separated routinely, stimulated by PMA, ionomycin and monensin, and the production of IL-4, IFN-γ and TGF-β by CD4+ T cells was observed by flow cytometry(FACS). Results: The percentages of the T cells producing IFN-γ, IL-4 or TGF-β ranged from 2.3% to 18.6%, 1.1% to 8.7% and 0.7% to 7.1% respectively among CD4+ cells from non-infected individuals. The majority of CD4+ T cells in PBMCs from individuals with chronic HBV infection were Th0 cells. The proportion of Th1 cells in patients with active chronic hepatitis B was higher than that in patients at inactive stage of the disease (P<0.05), indicating a significant elevation of Thl cells with the hepatic inflammation activity. The percentage of Th2 cells in individuals with HBV infection was higher than that in controls (P<0.05),but showed no difference between different patients (P>0.05). The percentage of Th3 cells was higher in asymptomatic HBV carriers than that in patients with chronic hepatitis B and in healthy controls (P<0.05). Conclusions: Th1-type cytokines are related with hepatic inflammation activity of chronic hepatitis B, and Th2 cells may be associated with the persistence of HBV infection. Th3 cells cooperating with Th2 cells are likely to function as negative immunoregulator, and may be responsible for the immune tolerance state of chronic HBV infection.

  13. Polarization and Dielectric Study of Methylammonium Lead Iodide Thin Film to Reveal its Nonferroelectric Nature under Solar Cell Operating Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hoque, Md Nadim Ferdous; Yang, Mengjin; Li, Zhen; Islam, Nazifah; Pan, Xuan; Zhu, Kai; Fan, Zhaoyang

    2016-07-08

    Researchers have debated whether methylammonium lead iodide (MAPbI3), with a perovskite crystal structure, is ferroelectric and therefore contributes to the current--voltage hysteresis commonly observed in hybrid perovskite solar cells (PSCs). We thoroughly investigated temperature-dependent polarization, dielectric, and impedance spectroscopies, and we found no evidence of ferroelectric effect in a MAPbI3 thin film at normal operating conditions. Therefore, the effect does not contribute to the hysteresis in PSCs, whereas the large component of ionic migration observed may play a critical role. Our temperature-based polarization and dielectric studies find that MAPbI3 exhibits different electrical behaviors below and above ca. 45 degrees C, suggesting a phase transition around this temperature. In particular, we report the activation energies of ionic migration for the two phases and temperature-dependent permittivity of MAPbI3. This study contributes to the understanding of the material properties and device performance of hybrid perovskites.

  14. Exocytosis and polarity in plant cells: insights by studying cellulose synthase complexes and the exocyst

    NARCIS (Netherlands)

    Ying Zhang, Ying

    2012-01-01

    The work presented in this thesis covers aspects of exocytosis, plant cell growth and cell wall formation. These processes are strongly linked as cell growth and cell wall formation occur simultaneously and exocytosis is the process that delivers cell wall components to the existing cell wall and in

  15. Measurement of Reproducibility for CSRm Dipoles

    Institute of Scientific and Technical Information of China (English)

    SuYalong; HeYuan; YuanPing; MaLizhen; LiuWeijun; HanShaofei; ZhangSiling

    2003-01-01

    The reproducibility of CSRm dipoles is an important factor to be considered in CSR project. There have seventeen dipoles in the cooling storage main ring (CSRm). The reproducibility of seventeen dipoles should be better than 2×10-4 at the optimum magnetic held. The longest in the seventeen dipoles is chosen as the reference magnet;. The reproducibility is derived as

  16. Inter-tissue mechanical stress affects Frizzled-mediated planar cell polarity in the Drosophila notum epidermis

    Science.gov (United States)

    Olguín, Patricio; Glavic, Alvaro; Mlodzik, Marek

    2011-01-01

    Summary Frizzled/Planar Cell Polarity (Fz/PCP) signaling controls the orientation of sensory bristles and cellular hairs (trichomes) along the antero-posterior axis of the Drosophila thorax (notum) [1–4]. A subset of the trichome-producing notum cells differentiate as “tendon cells”, serving as attachment sites for the indirect flight muscles (IFMs) to the exoskeleton [5]. Through the analysis of chascon (chas), a gene identified by its ability to disrupt Fz/PCP signaling under overexpression conditions, and jitterbug (jbug)/filamin [6], we show that maintenance of antero-posterior planar polarization requires the notum epithelia to balance mechanical stress generated by the attachment of the IFMs. chas is expressed in notum tendon cells and its loss-of-function disturbs cellular orientation at and near the regions where IFMs attach to the epidermis. This effect is independent of the Fz/PCP and fat (ft)/dachsous (ds) systems [7]. The chas phenotype arises during normal shortening of the IFMs [8] and is suppressed by genetic ablation of the IFMs. chas acts through jbug/filamin and cooperates with MyosinII to modulate the mechano-response of notum tendon cells. These observations support the notion that the ability of epithelia to respond to mechanical stress generated by interaction(s) with other tissues during development/organogenesis influences the maintenance of its shape and PCP features. PMID:21276726

  17. Activation-Induced T Helper Cell Death Contributes to Th1/Th2 Polarization following Murine Schistosoma japonicum Infection

    Directory of Open Access Journals (Sweden)

    Xinyu Xu

    2010-01-01

    Full Text Available In chronic infectious diseases, such as schistosomiasis, pathogen growth and immunopathology are affected by the induction of a proper balanced Th1/Th2 response to the pathogen and by antigen-triggered activation-induced T cell death. Here, by using S. japonicum infection or schistosome antigens-immunized mouse model, or antigens in vitro stimulation, we report that during the early stage of S. japonicum infection, nonegg antigens trigger Th2 cell apoptosis via the granzyme B signal pathway, contributing to Th1 polarization, which is thought to be associated with worm clearance and severe schistosomiasis. Meanwhile, after the adult worms lay their eggs, the egg antigens trigger Th1 cell apoptosis via the caspase pathway, contributing to Th2 polarization, which is associated with mild pathology and enhanced survival of both worms and their hosts. Thus, our study suggests that S. japonicum antigen-induced Th1 and Th2 cell apoptosis involves the Th1/Th2 shift and favorites both hosts and parasites.

  18. Chronic, low-dose rotenone reproduces Lewy neurites found in early stages of Parkinson's disease, reduces mitochondrial movement and slowly kills differentiated SH-SY5Y neural cells

    Directory of Open Access Journals (Sweden)

    Liu Lei

    2008-12-01

    Full Text Available Abstract Background Parkinson's disease, the most common adult neurodegenerative movement disorder, demonstrates a brain-wide pathology that begins pre-clinically with alpha-synuclein aggregates ("Lewy neurites" in processes of gut enteric and vagal motor neurons. Rostral progression into substantia nigra with death of dopamine neurons produces the motor impairment phenotype that yields a clinical diagnosis. The vast majority of Parkinson's disease occurs sporadically, and current models of sporadic Parkinson's disease (sPD can utilize directly infused or systemic neurotoxins. Results We developed a differentiation protocol for human SH-SY5Y neuroblastoma that yielded non-dividing dopaminergic neural cells with long processes that we then exposed to 50 nM rotenone, a complex I inhibitor used in Parkinson's disease models. After 21 days of rotenone, ~60% of cells died. Their processes retracted and accumulated ASYN-(+ and UB-(+ aggregates that blocked organelle transport. Mitochondrial movement velocities were reduced by 8 days of rotenone and continued to decline over time. No cytoplasmic inclusions resembling Lewy bodies were observed. Gene microarray analyses showed that the majority of genes were under-expressed. qPCR analyses of 11 mtDNA-encoded and 10 nDNA-encoded mitochondrial electron transport chain RNAs' relative expressions revealed small increases in mtDNA-encoded genes and lesser regulation of nDNA-encoded ETC genes. Conclusion Subacute rotenone treatment of differentiated SH-SY5Y neuroblastoma cells causes process retraction and partial death over several weeks, slowed mitochondrial movement in processes and appears to reproduce the Lewy neuritic changes of early Parkinson's disease pathology but does not cause Lewy body inclusions. The overall pattern of transcriptional regulation is gene under-expression with minimal regulation of ETC genes in spite of rotenone's being a complex I toxin. This rotenone-SH-SY5Y model in a

  19. The role of polar pili in the adherence of Pseudomonas aeruginosa to injured canine tracheal cells: a semiquantitative morphologic study.

    Science.gov (United States)

    Zoutman, D E; Hulbert, W C; Pasloske, B L; Joffe, A M; Volpel, K; Trebilcock, M K; Paranchych, W

    1991-03-01

    Pseudomonas aeruginosa adheres to respiratory epithelial cells in a highly specific fashion. In order to study the role of P. aeruginosa polar pili in the adherence process we conducted a quantitative morphological electron microscopic examination of P. aeruginosa adherence to SO2 injured canine tracheal cells in vitro. A pilin lacking background strain of P. aeruginosa PAK (BLP2) was constructed using a gene replacement and it in turn was engineered to express either the pilin gene of P. aeruginosa PAO, PAK, or no pilin gene. After 30 minutes incubation of these bacterial strains with injured canine tracheal rings the P. aeruginosa strains expressing pili adhered quantitatively more to the injured tracheal cells than did the pili lacking strains. PAO bearing strains adhered in greater numbers than PAK bearing strains. Healthy tracheal cells did not have any bacteria bound to their surfaces. The bacteria bound to the cilia and lateral edge of the exfoliating tracheal cells. Invasion of tracheal cells by piliated P. aeruginosa bacteria and penetration into the submucosa was also demonstrated. These data confirm the role of pili as important adhesins to injured tracheal cells. The difference in the adherence characteristics of pilin types PAK versus PAO may relate to the differences in the primary structure of these two pilin molecules. PMID:1675811

  20. Granulocytic Myeloid-Derived Suppressor Cells Accumulate in Human Placenta and Polarize toward a Th2 Phenotype.

    Science.gov (United States)

    Köstlin, Natascha; Hofstädter, Kathrin; Ostermeir, Anna-Lena; Spring, Bärbel; Leiber, Anja; Haen, Susanne; Abele, Harald; Bauer, Peter; Pollheimer, Jürgen; Hartl, Dominik; Poets, Christian F; Gille, Christian

    2016-02-01

    Tolerance induction toward the semiallogeneic fetus is crucial to enable a successful pregnancy; its failure is associated with abortion or preterm delivery. Skewing T cell differentiation toward a Th2-dominated phenotype seems to be pivotal in maternal immune adaption, yet underlying mechanisms are incompletely understood. Myeloid-derived suppressor cells (MDSCs) are innate immune cells that mediate T cell suppression and are increased in cord blood of healthy newborns and in peripheral blood of pregnant women. In this study, we demonstrate that granulocytic MDSCs (GR-MDSCs) accumulate in human placenta of healthy pregnancies but are diminished in patients with spontaneous abortions. Placental GR-MDSCs effectively suppressed T cell responses by expression of arginase I and production of reactive oxygen species and were activated at the maternal-fetal interface through interaction with trophoblast cells. Furthermore, GR-MDSCs isolated from placenta polarized CD4(+) T cells toward a Th2 cytokine response. These results highlight a potential role of GR-MDSCs in inducing and maintaining maternal-fetal tolerance and suggest them as a promising target for therapeutic manipulation of pregnancy complications. PMID:26712947

  1. Review of Polarized Ion Sources

    Science.gov (United States)

    Zelenski, A.

    2016-02-01

    Recent progress in polarized ion sources development is reviewed. New techniques for production of polarized H‑ ion (proton), D‑ (D+) and 3He++ ion beams will be discussed. A novel polarization technique was successfully implemented for the upgrade of the RHIC polarized H‑ ion source to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from an external source) in the He-gas ionizer cell. Polarized electron capture from the optically-pumped Rb vapor further produces proton polarization (Optically Pumped Polarized Ion Source technique). The upgraded source reliably delivered beam for the 2013 polarized run in RHIC at S = 510 GeV. This was a major factor contributing to RHIC polarization increase to over 60 % for colliding beams. Feasibility studies of a new polarization technique for polarized 3He++ source based on BNL Electron Beam Ion Source is also discussed.

  2. Assessment of crystal quality and unit cell orientation in epitaxial Cu₂ZnSnSe₄ layers using polarized Raman scattering.

    Science.gov (United States)

    Krämmer, Christoph; Lang, Mario; Redinger, Alex; Sachs, Johannes; Gao, Chao; Kalt, Heinz; Siebentritt, Susanne; Hetterich, Michael

    2014-11-17

    We use polarization-resolved Raman spectroscopy to assess the crystal quality of epitaxial kesterite layers. It is demonstrated for the example of epitaxial Cu₂ZnSnSe₄ layers on GaAs(001) that "standing" and "lying" kesterite unit cell orientations (c'-axis parallel / perpendicular to the growth direction) can be distinguished by the application of Raman tensor analysis. From the appearance of characteristic intensity oscillations when the sample is rotated one can distinguish polycrystalline and epitaxial layers. The method can be transferred to kesterite layers oriented in any crystal direction and can shed light on the growth of such layers in general. PMID:25402065

  3. Polarization of the epithelial layer and apical localization of integrins are required for engulfment of apoptotic cells in the Drosophila ovary

    Directory of Open Access Journals (Sweden)

    Tracy L. Meehan

    2015-12-01

    Full Text Available Inefficient clearance of dead cells or debris by epithelial cells can lead to or exacerbate debilitating conditions such as retinitis pigmentosa, macular degeneration, chronic obstructive pulmonary disease and asthma. Despite the importance of engulfment by epithelial cells, little is known about the molecular changes that are required within these cells. The misregulation of integrins has previously been associated with disease states, suggesting that a better understanding of the regulation of receptor trafficking could be key to treating diseases caused by defects in phagocytosis. Here, we demonstrate that the integrin heterodimer αPS3/βPS becomes apically enriched and is required for engulfment by the epithelial follicle cells of the Drosophila ovary. We found that integrin heterodimer localization and function is largely directed by the α-subunit. Moreover, proper cell polarity promotes asymmetric integrin enrichment, suggesting that αPS3/βPS trafficking occurs in a polarized fashion. We show that several genes previously known for their roles in trafficking and cell migration are also required for engulfment. Moreover, as in mammals, the same α-integrin subunit is required by professional and non-professional phagocytes and migrating cells in Drosophila. Our findings suggest that migrating and engulfing cells use common machinery, and demonstrate a crucial role for integrin function and polarized trafficking of integrin subunits during engulfment. This study also establishes the epithelial follicle cells of the Drosophila ovary as a powerful model for understanding the molecular changes required for engulfment by a polarized epithelium.

  4. The ex vivo Microenviroments in MLTC of Poorly Immunogenic Tumor Cells Facilitate Polarization of CD4+CD25+ Regulatory T Cells

    Institute of Scientific and Technical Information of China (English)

    Le Zhou; Hongyan Wang; Juxiang Xiao; Lusheng Si; Yili Wang

    2006-01-01

    CD4+CD25+ regulatory T (TR) cells play an important role in maintaining a balanced peripheral immune system.Recent studies have shown that TR cells may also play a key role in suppressing anti-tumor immune response. In order to investigate the tumor immune microenvironment and its influence on TR polarization, poorly immunogenic tumor cell line D5 (C57BL/6, H-2b), immunogenic tumor cell lines FBL3 (C57BL/6, H-2b) and H22 BALB/c, H-2d) were used to establish the syngeneic/allogeneic, poorly immunogenic/immunogenic mixed lymphocytes-tumor cell culture (MLTC). Our results revealed that the proportion of CD4+CD25+ T cells in MLTC of syngeneic primed splenocytes stimulated with D5 tumor cells was higher than that with H22 cells (0.43% vs 0.044%, and the similar results appeared in allogeneic splenocytes stimulated with D5 tumor cells (0.39% vs 0.04%).The splenocytes stimulated with supernatant from syngeneic MLTC of D5 tumor cells demonstrated higher proportion of CD4+CD25+ cells than that from allogeneic MLTC of D5 tumor cells, and the splenocytes stimulated with supernatant from syngeneic or allogeneic MLTC of H22 tumor cells generated lower proportion of CD4+CD25+ T cells than that of D5 tumor cells. The TGF-β1 and Th2-oriented cytokines (IL-4 and IL-10) were dominated in supernatants of syngeneic MLTC of poorly immunogenic tumor cells. Our results provided useful information for studying the mechanisms underlying tumor immune surveillance as well as for the tumor immunotherapy.

  5. Reproducible Ultrahigh Electromagnetic SERS Enhancement in Nanosphere-Plane Junctions

    CERN Document Server

    Long, Jing; Li, Hongquan; Yang, Tian

    2015-01-01

    Surface enhanced Raman scattering (SERS) in nanoscale hotspots has been placed great hopes upon for identification of minimum chemical traces and in-situ investigation of single molecule structures and dynamics. However, previous work consists of either irreproducible enhancement factors (EF) from random aggregates, or moderate EFs despite better reproducibility. Consequently, systematic study of SERS at the single and few molecules level is still very limited, and the promised applications are far from being realized. Here we report EFs as high as the most intense hotspots in previous work yet achieved in a reproducible and well controlled manner, that is, electromagnetic EFs (EMEF) of 10^9~10 with an error down to 10^+/-0.08 from gold nanospheres on atomically flat gold planes under radially polarized (RP) laser excitation. In addition, our experiment reveals the EF's unexpected nonlinearity under as low as hundreds of nanowatts of laser power.

  6. CagA+ H pylori infection is associated with polarization of T helper cell immune responses in gastric carcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Shu-Kui Wang; Hui-Fang Zhu; Bang-Shun He; Zhen-Yu Zhang; Zhi-Tan Chen; Zi-Zheng Wang; Guan-Ling Wu

    2007-01-01

    AIM: To characterize the immune responses including local and systemic immunity induced by infection with H pylori, especially with CagA+ H pylori strains and the underlying immunopathogenesis.METHODS: A total of 711 patients with different gastric lesions were recruited to determine the presence of H pylori infection and cytotoxin associated protein A (CagA), the presence of T helper (Th) cells and regulatory T (Treg)cells in peripheral blood mononuclear cells (PBMCs),expression of plasma cytokines, and RNA and protein expression of IFN-γ and IL-4 in gastric biopsies and PBMCs were determined by rapid urease test, urea [14C]breath test, immunoblotting test, flow cytometry, real time RT-PCR and immunohistochemistry.RESULTS: Of the patients, 629 (88.47%) were infected with H pylori; 506 (71.16%) with CagA+ and 123 (17.30%) with CagA- strains. Among patients infected with CagA+ H pylori strains, Th1-mediated cellular immunity was associated with earlier stages of gastric carcinogenesis, while Th2-mediated humoral immunity dominated the advanced stages and was negatively associated with an abundance of Treg cells. However,there was no such tendency in Th1/Th2 polarization in patients infected with CagA- H pylori strains and those without H pylori infection,CONCLUSION: Polarization of Th cell immune responses occurs in patients with CagA+ H pylori infection, which is associated with the stage and severity of gastric pathology during the progression of gastric carcinogenesis. This finding provides further evidence for a causal role of CagA+ H pylori infection in the immunopathogenesis of gastric cancer.

  7. PINCH1 regulates cell-matrix and cell-cell adhesions, cell polarity and cell survival during the peri-implantation stage

    DEFF Research Database (Denmark)

    Li, Shaohua; Bordoy, Randi; Stanchi, Fabio;

    2005-01-01

    integrin or Ilk, loss of PINCH1 arrested development at the peri-implantation stage. In contrast to beta1 integrin or Ilk mutants, however, disruption of the PINCH1 gene produced implantation chambers with visible cell clumps even at embryonic day 9.5. In order to define the phenotype leading to the peri...

  8. Calculation of the Reproducing Kernel on the Reproducing Kernel Space with Weighted Integral

    OpenAIRE

    Er Gao; Songhe Song; Xinjian Zhang

    2012-01-01

    We provide a new definition for reproducing kernel space with weighted integral and present a method to construct and calculate the reproducing kernel for the space. The new reproducing kernel space is an enlarged reproducing kernel space, which contains the traditional reproducing kernel space. The proposed method of this paper is a universal method and is suitable for the case of that the weight is variable. Obviously, this new method will generalize a number of applications ...

  9. Modeling self-organized spatio-temporal patterns of PIP3 and PTEN during spontaneous cell polarization

    International Nuclear Information System (INIS)

    During spontaneous cell polarization of Dictyostelium discoideum cells, phosphatidylinositol (3,4,5)-triphoshpate (PIP3) and PTEN (phosphatase tensin homolog) have been identified as key signaling molecules which govern the process of polarization in a self-organized manner. Recent experiments have quantified the spatio-temporal dynamics of these signaling components. Surprisingly, it was found that membrane-bound PTEN can be either in a high or low state, that PIP3 waves were initiated in areas lacking PTEN through an excitable mechanism, and that PIP3 was degraded even though the PTEN concentration remained low. Here we develop a reaction-diffusion model that aims to explain these experimental findings. Our model contains bistable dynamics for PTEN, excitable dynamics for PIP3, and postulates the existence of two species of PTEN with different dephosphorylation rates. We show that our model is able to produce results that are in good qualitative agreement with the experiments, suggesting that our reaction-diffusion model underlies the self-organized spatio-temporal patterns observed in experiments. (paper)

  10. The exon junction complex regulates the splicing of cell polarity gene dlg1 to control Wingless signaling in development

    Science.gov (United States)

    Liu, Min; Li, Yajuan; Liu, Aiguo; Li, Ruifeng; Su, Ying; Du, Juan; Li, Cheng; Zhu, Alan Jian

    2016-01-01

    Wingless (Wg)/Wnt signaling is conserved in all metazoan animals and plays critical roles in development. The Wg/Wnt morphogen reception is essential for signal activation, whose activity is mediated through the receptor complex and a scaffold protein Dishevelled (Dsh). We report here that the exon junction complex (EJC) activity is indispensable for Wg signaling by maintaining an appropriate level of Dsh protein for Wg ligand reception in Drosophila. Transcriptome analyses in Drosophila wing imaginal discs indicate that the EJC controls the splicing of the cell polarity gene discs large 1 (dlg1), whose coding protein directly interacts with Dsh. Genetic and biochemical experiments demonstrate that Dlg1 protein acts independently from its role in cell polarity to protect Dsh protein from lysosomal degradation. More importantly, human orthologous Dlg protein is sufficient to promote Dvl protein stabilization and Wnt signaling activity, thus revealing a conserved regulatory mechanism of Wg/Wnt signaling by Dlg and EJC. DOI: http://dx.doi.org/10.7554/eLife.17200.001 PMID:27536874

  11. Macrophage polarization reflects T cell composition of tumor microenvironment in pediatric classical Hodgkin lymphoma and has impact on survival.

    Directory of Open Access Journals (Sweden)

    Mário H M Barros

    Full Text Available Macrophages have been implicated in the pathogenesis of classical Hodgkin lymphoma (cHL and have been suggested to have a negative impact on outcome. Most studies addressing the role of macrophages in cHL have relied on identification of macrophages by generic macrophage antigens, e.g., CD68. We have therefore conducted an in situ analysis of macrophage polarization in a series of 100 pediatric cHL (pcHL cases using double staining immunohistochemistry, combining CD68 or CD163 with pSTAT1 (M1-like or CMAF (M2-like. M1- or M2-polarised microenvironment was defined by an excess of one population over the other (>1.5. Expression of STAT1 and LYZ genes was also evaluated by RT-qPCR. Patients 1.5 was associated with higher numbers of CD68+pSTAT1+ (P=0.025 and CD163+pSTAT1+ macrophages (P 1.5 was associated with better OS (P= 0.037. In conclusion, macrophage polarization in pcHL correlates with prevalent local T cell response and may be influenced by the EBV-status of neoplastic cells. Besides, M1-like and M2-like macrophages displayed differential effects on outcome in pcHL.

  12. Compact Circularly Polarized Patch Antenna Using a Composite Right/Left-Handed Transmission Line Unit-Cell

    Directory of Open Access Journals (Sweden)

    L. Geng

    2013-04-01

    Full Text Available A compact circularly polarized (CP patch antenna using a composite right/left-handed (CRLH transmission line (TL unit-cell is proposed. The CRLH TL unit-cell includes a complementary split ring resonator (CSRR for shunt inductance and a gap loaded with a circular-shaped slot for series capacitance. The CSRR can decrease the TM10 mode resonance frequency, thus reducing the electrical size of the proposed antenna. In addition, the asymmetry of the CSRR brings about the TM01 mode, which can be combined with the TM10 mode by changing the slot radius. The combination of these two orthogonal modes with 90° phase shift makes the proposed antenna provide a CP property. The experimental results show that the proposed antenna has a wider axial ratio bandwidth and a smaller electrical size than the reported CP antennas. Moreover, the proposed antenna is designed without impedance transformer, 90° phase shift, dual feed and ground via.

  13. Flagellin-induced tolerance of the Toll-like receptor 5 signaling pathway in polarized intestinal epithelial cells.

    Science.gov (United States)

    Sun, Jun; Fegan, Pamela E; Desai, Anjali S; Madara, James L; Hobert, Michael E

    2007-03-01

    Salmonella typhimurium is a gram-negative enteric pathogen that invades the mucosal epithelium and is associated with diarrheal illness in humans. Flagellin from S. typhimurium and other gram-negative bacteria has been shown to be the predominant proinflammatory mediator through activation of the basolateral Toll-like receptor 5 (TLR5). Recent evidence has shown that prior exposure can render immune cells tolerant to subsequent challenges by TLR ligands. Accordingly, we examined whether prior exposure to purified flagellin would render human intestinal epithelial cells insensitive to future contact. We found that flagellin-induced tolerance is common to polarized epithelial cells and prevents further activation of proinflammatory signaling cascades by both purified flagellin and Salmonella bacteria but does not affect TNF-alpha stimulation of the same pathways. Flagellin tolerance is a rapid process that does not require protein synthesis, and that occurs within 1 to 2 h of flagellin exposure. Prolonged flagellin exposure blocks activation of the NF-kappaB, MAPK, and phosphoinositol 3-kinase signaling pathways and results in the internalization of a fraction of the basolateral TLR5 without affecting the polarity or total expression of TLR5. After removal of flagellin, cells require more than 24 h to fully recover their ability to mount a normal proinflammatory response. We have found that activation of phosphoinositol 3-kinase and Akt by flagellin has a small damping effect in the early stages of flagellin signaling but is not responsible for tolerance. Our study indicates that inhibition of TLR5-associated IL-1 receptor-associated kinase-4 activity occurs during the development of flagellin tolerance and is likely to be the cause of tolerance. PMID:17138965

  14. Entry and release of transmissible gastroenteritis coronavirus are restricted to apical surfaces of polarized epithelial cells

    NARCIS (Netherlands)

    Rossen, J W; Bekker, C P; Voorhout, W F; Strous, G J; van der Ende, A; Rottier, P J

    1994-01-01

    The transmissible gastroenteritis coronavirus (TGEV) infects the epithelial cells of the intestinal tract of pigs, resulting in a high mortality rate in piglets. This study shows the interaction of TGEV with a porcine epithelial cell line. To determine the site of viral entry, LLC-PK1 cells were gro

  15. Radiation-Induced RhoGDIβ Cleavage Leads to Perturbation of Cell Polarity: A Possible Link to Cancer Spreading.

    Science.gov (United States)

    Fujiwara, Mamoru; Okamoto, Mayumi; Hori, Masato; Suga, Hiroshi; Jikihara, Hiroshi; Sugihara, Yuka; Shimamoto, Fumio; Mori, Toshio; Nakaoji, Koichi; Hamada, Kazuhiko; Ota, Takahide; Wiedemuth, Ralf; Temme, Achim; Tatsuka, Masaaki

    2016-11-01

    The equilibrium between proliferation and apoptosis is tightly balanced to maintain tissue homeostasis in normal tissues and even in tumors. Achieving and maintaining such a balance is important for cancer regrowth and spreading after cytotoxic treatments. Caspase-3 activation and tumor cell death following anticancer therapy as well as accompanying cell death pathways are well characterized, but their association to homeostasis of cancerous tissue and tumor progression remains poorly understood. Here we proposed a novel mechanism of cancer spreading induced by caspase-3. RhoGDIβ, known as a direct cleavage substrate of caspase-3, is overexpressed in many epithelial cancers. The N-terminal-truncated RhoGDIβ (ΔN-RhoGDIβ) is accumulated in caspase-3-activated cells. Stable expression of ΔN-RhoGDIβ in HeLa cells did not induce apoptosis, but impaired directional cell migration in a wound-healing assay accompanied by a perturbed direction of cell division at the wound edge. Subcellular protein fractionation experiments revealed that ΔN-RhoGDIβ but not wild-type RhoGDIβ was present in the detergent-soluble cytoplasmic and nuclear fractions and preferentially associated with Cdc42. Furthermore, Cdc42 activity was constitutively inhibited by stable expression of ΔN-RhoGDIβ, resulting in increased radiation-induced compensatory proliferation linking to RhoA activation. Thus, ΔN-RhoGDIβ dominant-negatively regulates Cdc42 activity and contributes to loss of polarity-related functions. The caspase-3-cleaved RhoGDIβ is a possible determinant to promote cancer spreading due to deregulation of directional organization of tumor cell population and inhibition of default equilibrium between proliferation and apoptosis after cytotoxic damage. J. Cell. Physiol. 231: 2493-2505, 2016. © 2016 Wiley Periodicals, Inc. PMID:26919575

  16. Macrophage polarization in nerve injury:do Schwann cells play a role?

    Institute of Scientific and Technical Information of China (English)

    Jo Anne Stratton; Prajay T Shah

    2016-01-01

    In response to peripheral nerve injury, the inlfammatory response is almost entirely comprised of inifltrat-ing macrophages. Macrophages are a highly plastic, heterogenic immune cell, playing an indispensable role in peripheral nerve injury, clearing debris and regulating the microenvironment to allow for efifcient regen-eration. There are several cells within the microenvironment that likely interact with macrophages to support their function –most notably the Schwann cell, the glial cell of the peripheral nervous system. Schwann cells express several ligands that are known to interact with receptors expressed by macrophages, yet the effects of Schwann cells in regulating macrophage phenotype remains largely unexplored. This review discusses macrophages in peripheral nerve injury and how Schwann cells may regulate their behavior.

  17. Model for self-polarization and motility of keratocyte fragments

    KAUST Repository

    Ziebert, F.

    2011-10-19

    Computational modelling of cell motility on substrates is a formidable challenge; regulatory pathways are intertwined and forces that influence cell motion are not fully quantified. Additional challenges arise from the need to describe a moving deformable cell boundary. Here, we present a simple mathematical model coupling cell shape dynamics, treated by the phase-field approach, to a vector field describing the mean orientation (polarization) of the actin filament network. The model successfully reproduces the primary phenomenology of cell motility: discontinuous onset of motion, diversity of cell shapes and shape oscillations. The results are in qualitative agreement with recent experiments on motility of keratocyte cells and cell fragments. The asymmetry of the shapes is captured to a large extent in this simple model, which may prove useful for the interpretation of experiments.

  18. Reproducibility principles, problems, practices, and prospects

    CERN Document Server

    Maasen, Sabine

    2016-01-01

    Featuring peer-reviewed contributions from noted experts in their fields of research, Reproducibility: Principles, Problems, Practices, and Prospects presents state-of-the-art approaches to reproducibility, the gold standard sound science, from multi- and interdisciplinary perspectives. Including comprehensive coverage for implementing and reflecting the norm of reproducibility in various pertinent fields of research, the book focuses on how the reproducibility of results is applied, how it may be limited, and how such limitations can be understood or even controlled in the natural sciences, computational sciences, life sciences, social sciences, and studies of science and technology. The book presents many chapters devoted to a variety of methods and techniques, as well as their epistemic and ontological underpinnings, which have been developed to safeguard reproducible research and curtail deficits and failures. The book also investigates the political, historical, and social practices that underlie repro...

  19. A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using quantitative nuclear magnetic resonance.

    Science.gov (United States)

    Goldoni, Luca; Beringhelli, Tiziana; Rocchia, Walter; Realini, Natalia; Piomelli, Daniele

    2016-05-15

    Absolute analyte quantification by nuclear magnetic resonance (NMR) spectroscopy is rarely pursued in metabolomics, even though this would allow researchers to compare results obtained using different techniques. Here we report on a new protocol that permits, after pH-controlled serum protein removal, the sensitive quantification (limit of detection [LOD] = 5-25 μM) of hydrophilic nutrients and metabolites in the extracellular medium of cells in cultures. The method does not require the use of databases and uses PULCON (pulse length-based concentration determination) quantitative NMR to obtain results that are significantly more accurate and reproducible than those obtained by CPMG (Carr-Purcell-Meiboom-Gill) sequence or post-processing filtering approaches. Three practical applications of the method highlight its flexibility under different cell culture conditions. We identified and quantified (i) metabolic differences between genetically engineered human cell lines, (ii) alterations in cellular metabolism induced by differentiation of mouse myoblasts into myotubes, and (iii) metabolic changes caused by activation of neurotransmitter receptors in mouse myoblasts. Thus, the new protocol offers an easily implementable, efficient, and versatile tool for the investigation of cellular metabolism and signal transduction. PMID:26898303

  20. In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source.

    Science.gov (United States)

    Tong, X; Jiang, C Y; Lauter, V; Ambaye, H; Brown, D; Crow, L; Gentile, T R; Goyette, R; Lee, W T; Parizzi, A; Robertson, J L

    2012-07-01

    We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously. PMID:22852718

  1. Complement protein C1q directs macrophage polarization and limits inflammasome activity during the uptake of apoptotic cells

    Science.gov (United States)

    Benoit, Marie E.; Clarke, Elizabeth V.; Morgado, Pedro; Fraser, Deborah A.; Tenner, Andrea J.

    2012-01-01

    Deficiency in C1q, the recognition component of the classical complement cascade and a pattern recognition receptor involved in apoptotic cell clearance, leads to lupus-like auto-immune diseases characterized by auto-antibodies to self proteins and aberrant innate immune cell activation likely due to impaired clearance of apoptotic cells. Here, we developed an autologous system using primary human lymphocytes and monocyte-derived macrophages (HMDMs) to characterize the effect of C1q on macrophage gene expression profiles during the uptake of apoptotic cells. C1q bound to autologous apoptotic lymphocytes modulated expression of genes associated with JAK/STAT signaling, chemotaxis, immunoregulation and NLRP3 inflammasome activation in LPS-stimulated HMDMs. Specifically, C1q sequentially induced type I interferons (IFNs), IL-27 and IL-10 in LPS-stimulated HMDMs and IL-27 in HMDMs when incubated with AL conditioned media. Co-incubation with C1q tails prevented the induction of type I IFNs and IL-27 in a dose dependent manner and neutralization of type I IFNs partially prevented IL-27 induction by C1q. Finally, C1q decreased procaspase-1 cleavage and caspase-1 dependent cleavage of IL-1β suggesting potent inhibitory effect of C1q on inflammasome activation. These results identify specific molecular pathways induced by C1q to suppress macrophage inflammation providing potential therapeutic targets to control macrophage polarization, and thus inflammation and autoimmunity. PMID:22523386

  2. Neisseria meningitidis subverts the polarized organization and intracellular trafficking of host cells to cross the epithelial barrier.

    Science.gov (United States)

    Barrile, Riccardo; Kasendra, Magdalena; Rossi-Paccani, Silvia; Merola, Marcello; Pizza, Mariagrazia; Baldari, Cosima; Soriani, Marco; Aricò, Beatrice

    2015-09-01

    Translocation of the nasopharyngeal barrier by Neisseria meningitidis occurs via an intracellular microtubule-dependent pathway and represents a crucial step in its pathogenesis. Despite this fact, the interaction of invasive meningococci with host subcellular compartments and the resulting impact on their organization and function have not been investigated. The influence of serogroup B strain MC58 on host cell polarity and intracellular trafficking system was assessed by confocal microscopy visualization of different plasma membrane-associated components (such as E-cadherin, ZO-1 and transferrin receptor) and evaluation of the transferrin uptake and recycling in infected Calu-3 monolayers. Additionally, the association of N. meningitidis with different endosomal compartments was evaluated through the concomitant staining of bacteria and markers specific for Rab11, Rab22a, Rab25 and Rab3 followed by confocal microscopy imaging. Subversion of the host cell architecture and intracellular trafficking system, denoted by mis-targeting of cell plasma membrane components and perturbations of transferrin transport, was shown to occur in response to N. meningitidis infection. Notably, the appearance of all of these events seems to positively correlate with the efficiency of N. meningitidis to cross the epithelial barrier. Our data reveal for the first time that N. meningitidis is able to modulate the host cell architecture and function, which might serve as a strategy of this pathogen for overcoming the nasopharyngeal barrier without affecting the monolayer integrity. PMID:25801707

  3. Essential function for PDLIM2 in cell polarization in three-dimensional cultures by feedback regulation of the β1-integrin-RhoA signaling axis.

    Science.gov (United States)

    Deevi, Ravi Kiran; Cox, Orla T; O'Connor, Rosemary

    2014-05-01

    PDLIM2 is a cytoskeletal and nuclear PDZ-LIM domain protein that regulates the stability of Nuclear Factor kappa-B (NFκB) and other transcription factors, and is required for polarized cell migration. PDLIM2 expression is suppressed by methylation in different cancers, but is strongly expressed in invasive breast cancer cells that have undergone an Epithelial Mesenchymal Transition (EMT). PDLIM2 is also expressed in non-transformed breast myoepithelial MCF10A cells and here we asked whether it is important for maintaining the polarized, epithelial phenotype of these cells. Suppression of PDLIM2 in MCF10A cells was sufficient to disrupt cell polarization and acini formation with increased proliferation and reduced apoptosis in the luminal space compared to control acini with hollow lumina. Spheroids with suppressed PDLIM2 exhibited increased expression of cell-cell and cell-matrix adhesion proteins including beta 1 (β1) integrin. Interestingly, levels of the Insulin-like growth factor 1 receptor (IGF-1 R) and Receptor of activated protein kinase C 1 (RACK1), which scaffolds IGF-1R to β1 integrin, were also increased, indicating a transformed phenotype. Focal Adhesion Kinase (FAK) and cofilin phosphorylation, and RhoA Guanosine Triphosphatase (GTPase) activity were all enhanced in these spheroids compared to control acini. Importantly, inhibition of either FAK or Rho Kinase (ROCK) was sufficient to rescue the polarity defect. We conclude that PDLIM2 expression is essential for feedback regulation of the β1-integrin-RhoA signalling axis and integration of cellular microenvironment signals with gene expression to control the polarity of breast epithelial acini structures. This is a mechanism by which PDLIM2 could mediate tumour suppression in breast epithelium. PMID:24863845

  4. Essential Function for PDLIM2 in Cell Polarization in Three-Dimensional Cultures by Feedback Regulation of the β1-Integrin–RhoA Signaling Axis

    Directory of Open Access Journals (Sweden)

    Ravi Kiran Deevi

    2014-05-01

    Full Text Available PDLIM2 is a cytoskeletal and nuclear PDZ-LIM domain protein that regulates the stability of Nuclear Factor kappa-B (NFκB and other transcription factors, and is required for polarized cell migration. PDLIM2 expression is suppressed by methylation in different cancers, but is strongly expressed in invasive breast cancer cells that have undergone an Epithelial Mesenchymal Transition (EMT. PDLIM2 is also expressed in non-transformed breast myoepithelial MCF10A cells and here we asked whether it is important for maintaining the polarized, epithelial phenotype of these cells. Suppression of PDLIM2 in MCF10A cells was sufficient to disrupt cell polarization and acini formation with increased proliferation and reduced apoptosis in the luminal space compared to control acini with hollow lumina. Spheroids with suppressed PDLIM2 exhibited increased expression of cell-cell and cell-matrix adhesion proteins including beta 1 (β1 integrin. Interestingly, levels of the Insulin-like growth factor 1 receptor (IGF-1 R and Receptor of activated protein kinase C 1 (RACK1, which scaffolds IGF-1R to β1 integrin, were also increased, indicating a transformed phenotype. Focal Adhesion Kinase (FAK and cofilin phosphorylation, and RhoA Guanosine Triphosphatase (GTPase activity were all enhanced in these spheroids compared to control acini. Importantly, inhibition of either FAK or Rho Kinase (ROCK was sufficient to rescue the polarity defect. We conclude that PDLIM2 expression is essential for feedback regulation of the β1-integrin-RhoA signalling axis and integration of cellular microenvironment signals with gene expression to control the polarity of breast epithelial acini structures. This is a mechanism by which PDLIM2 could mediate tumour suppression in breast epithelium.

  5. Polarized Th2 like cells, in the absence of Th0 cells, are responsible for lymphocyte produced IL-4 in high IgE-producer schistosomiasis patients

    Directory of Open Access Journals (Sweden)

    Soares-Silveira Alda

    2002-07-01

    Full Text Available Abstract Background Human resistance to re-infection with S. mansoni is correlated with high levels of anti-soluble adult worm antigens (SWAP IgE. Although it has been shown that IL-4 and IL-5 are crucial in establishing IgE responses in vitro, the active in vivo production of these cytokines by T cells, and the degree of polarization of Th2 vs. Th0 in human schistosomiasis is not known. To address this question, we determined the frequency of IL-4 and IFN-γ or IL-5 and IL-2 producing lymphocytes from schistosomiasis patients with high or low levels of IgE anti-SWAP. Results Our analysis showed that high and low IgE-producers responded equally to schistosomiasis antigens as determined by proliferation. Moreover, patients from both groups displayed similar percentages of circulating lymphocytes. However, high IgE-producers had an increased percentage of activated CD4+ T cells as compared to the low IgE-producers. Moreover, intracellular cytokine analysis, after short-term stimulation with anti-CD3/CD28 mAbs, showed that IgE high-producers display an increase in the percentage of T lymphocytes expressing IL-4 and IL-5 as compared to IgE low-responders. A coordinate control of the frequency of IL-4 and IL-5 producing lymphocytes in IgE high, but not IgE low-responders, was observed. Conclusions High IgE phenotype human schistosomiasis patients exhibit a coordinate regulation of IL-4 and IL-5 producing cells and the lymphocyte derived IL-4 comes from true polarized Th2 like cells, in the absence of measurable Th0 cells as measured by co-production of IL-4 and IFN-γ.

  6. Characterization and remote sensing of biological particles using circular polarization

    CERN Document Server

    Nagdimunov, Lev; Mackowski, Daniel

    2014-01-01

    Biological molecules are characterized by an intrinsic asymmetry known as homochirality. The result is optical activity of biological materials and circular polarization in the light scattered by microorganisms, cells of living organisms, as well as molecules (e.g. amino acids) of biological origin. Lab measurements (Sparks et al. 2009a, b) have found that light scattered by certain biological systems, in particular photosynthetic organisms, is not only circular polarized but contains a characteristic spectral trend, showing a fast change and reversal of sign for circular polarization within absorption bands. Similar behavior can be expected for other biological and prebiological organics, especially amino acids. We begin our study by reproducing the laboratory measurements for photosynthetic organisms through modeling the biological material as aggregated structures and using the Multiple Sphere T-matrix (MSTM) code for light scattering calculations. We further study how the spectral effect described above d...

  7. The Economics of Reproducibility in Preclinical Research.

    Directory of Open Access Journals (Sweden)

    Leonard P Freedman

    2015-06-01

    Full Text Available Low reproducibility rates within life science research undermine cumulative knowledge production and contribute to both delays and costs of therapeutic drug development. An analysis of past studies indicates that the cumulative (total prevalence of irreproducible preclinical research exceeds 50%, resulting in approximately US$28,000,000,000 (US$28B/year spent on preclinical research that is not reproducible-in the United States alone. We outline a framework for solutions and a plan for long-term improvements in reproducibility rates that will help to accelerate the discovery of life-saving therapies and cures.

  8. A long-term and reproducible passive microwave sea ice concentration data record for climate studies and monitoring

    Directory of Open Access Journals (Sweden)

    G. Peng

    2013-05-01

    Full Text Available A long-term, consistent, and reproducible satellite-based passive microwave sea ice concentration climate data record (CDR is available for climate studies, monitoring, and model validation with an initial operation capability (IOC. The daily and monthly sea ice concentration data are on the National Snow and Ice Data Center (NSIDC polar stereographic grid with nominal 25 × 25 km grid cells in both the Southern and Northern Hemisphere Polar Regions from 9 July 1987 to 31 December 2007 with an update through 2011 underway. The data files are available in the NetCDF data format at http://nsidc.org/data/g02202.html and archived by the National Oceanic and Atmospheric Administration (NOAA's National Climatic Data Center (NCDC under the satellite climate data record program (http://www.ncdc.noaa.gov/cdr/operationalcdrs.html. The description and basic characteristics of the NOAA/NSIDC passive microwave sea ice concentration CDR are presented here. The CDR provides similar spatial and temporal variability as the heritage products to the user communities with the additional documentation, traceability, and reproducibility that meet current standards and guidelines for climate data records. The dataset along with detailed data processing steps and error source information can be found at: doi:10.7265/N5B56GN3.

  9. Concomitant use of polarization and positive phase contrast microscopy for the study of microbial cells

    Czech Academy of Sciences Publication Activity Database

    Žižka, Zdeněk; Gabriel, Jiří

    2014-01-01

    Roč. 60, č. 6 (2014), s. 545-550. ISSN 0015-5632 Institutional support: RVO:61388971 Keywords : microbial cells * microscopy * microorganism Subject RIV: EE - Microbiology, Virology Impact factor: 1.000, year: 2014

  10. ABC-type transporters and cuticle assembly: Linking function to polarity in epidermis cells

    OpenAIRE

    Panikashvili, David; Aharoni, Asaph

    2008-01-01

    The aerial organs of plants are covered with a cuticle, a continuous layer overlaying the outermost cell walls of the epidermis. The cuticle is composed of two major classes of the lipid biopolymers: cutin and waxes, collectively termed cuticular lipids. Biosynthesis and transport of cuticular lipids occur predominantly in the epidermis cells. In the transport pathway, cuticular lipids are exported from their site of biosynthesis in the ER/plastid to the extracellular space through the plasma...

  11. Coupling Mechanical Deformations and Planar Cell Polarity to Create Regular Patterns in the Zebrafish Retina

    OpenAIRE

    Salbreux, Guillaume; Barthel, Linda K; Raymond, Pamela A.; Lubensky, David K.

    2012-01-01

    The orderly packing and precise arrangement of epithelial cells is essential to the functioning of many tissues, and refinement of this packing during development is a central theme in animal morphogenesis. The mechanisms that determine epithelial cell shape and position, however, remain incompletely understood. Here, we investigate these mechanisms in a striking example of planar order in a vertebrate epithelium: The periodic, almost crystalline distribution of cone photoreceptors in the adu...

  12. Time- and polarization-resolved cellular autofluorescence towards quantitative biochemistry on living cells

    Science.gov (United States)

    Alfveby, John; TImerman, Randi; Soto Velasquez, Monica P.; Wickramasinghe, Dhanushka W. P. M.; Bartusek, Jillian; Heikal, Ahmed A.

    2014-09-01

    Native coenzymes such as the reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide play pivotal roles in energy metabolism and a myriad of biochemical reactions in living cells/tissues. These coenzymes are naturally fluorescent and, therefore, have the potential to serve as intrinsic biomarkers for mitochondrial activities, programmed cell death (apoptosis), oxidative stress, aging, and neurodegenerative disease. In this contribution, we employ two-photon fluorescence lifetime imaging microscopy (FLIM) and time-resolved anisotropy imaging of intracellular NADH for quantitative, non-invasive biochemistry on living cells in response to hydrogenperoxide- induced oxidative stress. In contrast with steady-state one-photon, UV-excited autofluorescence, two-photon FLIM is sensitive to both molecular conformation and stimuli-induced changes in the local environment in living cells with minimum photodamage and inherently enhanced spatial resolution. On the other hand, time-resolved, two-photon anisotropy imaging of cellular autofluorescence allows for quantitative assessment of binding state and environmental restrictions on the tumbling mobility of intrinsic NADH. Our measurements reveal that free and enzyme-bound NADH exist at equilibrium, with a dominant autofluorescence contribution of the bound fraction in living cells. Parallel studies on NADH-enzyme binding in controlled environments serve as a point of reference in analyzing autofluorescence in living cells. These autofluorescence-based approaches complement the conventional analytical biochemistry methods that require the destruction of cells/tissues, while serving as an important step towards establishing intracellular NADH as a natural biomarker for monitoring changes in energy metabolism and redox state of living cells in response to environmental hazards.

  13. Polarization of Calcium Signaling and Fluid Secretion in Salivary Gland Cells

    OpenAIRE

    Ambudkar, I.S.

    2012-01-01

    The secretion of fluid, electrolytes, and protein by exocrine gland acinar cells is a vectorial process that requires the coordinated regulation of multiple channel and transporter proteins, signaling components, as well as mechanisms involved in vesicular fusion and water transport. Most critical in this is the regulation of cytosolic free [Ca2+] ([Ca2+]i) in response to neurotransmitter stimulation. Control of [Ca2+]i increase in specific regions of the cell is the main determinant of fluid...

  14. Anti-HMGB1 Neutralizing Antibody Ameliorates Neutrophilic Airway Inflammation by Suppressing Dendritic Cell-Mediated Th17 Polarization

    Directory of Open Access Journals (Sweden)

    Fang Zhang

    2014-01-01

    Full Text Available We demonstrate that high mobility group box 1 protein (HMGB1 directs Th17 skewing by regulating dendritic cell (DC function. First, our in vitro studies reveal that recombinant HMGB1 (rHMGB1 activates myeloid DCs to produce IL-23 in vitro, and rHMGB1-activated DCs prime naïve lymphocytes to produce the Th17 cytokine IL-17A. Second, we demonstrate that anti-HMGB1 neutralizing antibody attenuates HMGB1 expression, neutrophilic inflammation, airway hyperresponsiveness, and Th17-related cytokine secretion in vivo by using a murine model of neutrophilic asthma induced by ovalbumin (OVA plus lipopolysaccharide (LPS. Furthermore, anti-HMGB1 neutralizing antibody decreases the number of Th17 cells in lung cells and suppresses the production of IL-23 by lung CD11C+ APCs. Finally, we show that intranasal adoptive transfer of rHMGB1-activated DCs was sufficient to restore lung neutrophilic inflammation and the Th17 response in a DC-driven model of asthma, whereas the transfer of rHMGB1 plus anti-HMGB1-treated mDCs significantly reduced these inflammation phenotypes. These data suggest, for the first time, that HMGB1 drives the DC-polarized Th17-type response in allergic lung inflammation and that blocking HMGB1 may benefit the attenuation of neutrophilic airway inflammation in asthma.

  15. The Wnt/Planar Cell Polarity Pathway Component Vangl2 Induces Synapse Formation through Direct Control of N-Cadherin

    Directory of Open Access Journals (Sweden)

    Tadahiro Nagaoka

    2014-03-01

    Full Text Available Although regulators of the Wnt/planar cell polarity (PCP pathway are widely expressed in vertebrate nervous systems, their roles at synapses are unknown. Here, we show that Vangl2 is a postsynaptic factor crucial for synaptogenesis and that it coprecipitates with N-cadherin and PSD-95 from synapse-rich brain extracts. Vangl2 directly binds N-cadherin and enhances its internalization in a Rab5-dependent manner. This physical and functional interaction is suppressed by β-catenin, which binds the same intracellular region of N-cadherin as Vangl2. In hippocampal neurons expressing reduced Vangl2 levels, dendritic spine formation as well as synaptic marker clustering is significantly impaired. Furthermore, Prickle2, another postsynaptic PCP component, inhibits the N-cadherin-Vangl2 interaction and is required for normal spine formation. These results demonstrate direct control of classic cadherin by PCP factors; this control may play a central role in the precise formation and maturation of cell-cell adhesions at the synapse.

  16. Lack of Th1 or Th2 polarization of CD4+ T cell response induced by particulate antigen targeted to phagocytic cells.

    Science.gov (United States)

    Sedlik, C; Dériaud, E; Leclerc, C

    1997-01-01

    Several factors are involved in the selective activation of Th1 or Th2 subset of CD4+ T cells, such as the type of antigen-presenting cells, the dose of antigen, the route of immunization, etc. To analyze the influence of accessory cells on Th1/Th2 cell differentiation, we used a particulate antigen prepared by covalent linkage of hemocyanin (LH) to 1 microns synthetic microspheres. This particulate antigen was efficiently presented to T cells by macrophages but not by B lymphocytes. BALB/c mice immunized either with soluble LH in alum or with particulate LH without adjuvant produced both Th1 (IL-2 and IFN-gamma) and Th2 (IL-4 and IL-5) cytokines. Moreover, mice primed either with soluble or particulate LH secreted higher levels of IgG1- than of IgG2a-specific antibodies. The induction of this cytokine profile response was independent of the route of administration of the antigen, and was observed both in BALB/c and C57BL/6 mice. In contrast, immunization of mice with particulate LH in the presence of poly(I):(C) or of IL-12 induced a strong activation of Th1 cells, as shown by an up-regulated IFN-gamma production, and by decreased IL-4 and IL-5 levels associated to a greatly enhanced IgG2a antibody response. These results therefore demonstrate that targeting the antigen to phagocytic cells is not sufficient to stimulate a polarized Th response and that environmental cytokines play the major role in the selective activation of Th1 cells. This study provides important conclusions for the development of new vaccines and shows that particulate antigen associated with appropriate cofactor can selectively activate Th1 cells. PMID:9043951

  17. Reproducibility Experiment of OSL and TL Dosimeter

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Reproducibility is an important property of personal dosimeter. It not only can indicate the stability of dosimeter, appraise the precision and accuracy of measured value, but also can evaluate the

  18. Thou Shalt Be Reproducible! A Technology Perspective

    Science.gov (United States)

    Mair, Patrick

    2016-01-01

    This article elaborates on reproducibility in psychology from a technological viewpoint. Modern open source computational environments are shown and explained that foster reproducibility throughout the whole research life cycle, and to which emerging psychology researchers should be sensitized, are shown and explained. First, data archiving platforms that make datasets publicly available are presented. Second, R is advocated as the data-analytic lingua franca in psychology for achieving reproducible statistical analysis. Third, dynamic report generation environments for writing reproducible manuscripts that integrate text, data analysis, and statistical outputs such as figures and tables in a single document are described. Supplementary materials are provided in order to get the reader started with these technologies. PMID:27471486

  19. Transparent, reproducible and reusable research in pharmacoepidemiology

    NARCIS (Netherlands)

    Gardarsdottir, Helga; Sauer, Brian C.; Liang, Huifang; Ryan, Patrick; Klungel, Olaf; Reynolds, Robert

    2012-01-01

    Background: Epidemiological research has been criticized as being unreliable. Scientific evidence is strengthened when the study procedures of important findings are transparent, open for review, and easily reproduced by different investigators and in various settings. Studies often have common scie

  20. Reproducible statistical analysis with multiple languages

    DEFF Research Database (Denmark)

    Lenth, Russell; Højsgaard, Søren

    2011-01-01

    This paper describes the system for making reproducible statistical analyses. differs from other systems for reproducible analysis in several ways. The two main differences are: (1) Several statistics programs can be in used in the same document. (2) Documents can be prepared using OpenOffice or ......This paper describes the system for making reproducible statistical analyses. differs from other systems for reproducible analysis in several ways. The two main differences are: (1) Several statistics programs can be in used in the same document. (2) Documents can be prepared using Open......Office or \\LaTeX. The main part of this paper is an example showing how to use and together in an OpenOffice text document. The paper also contains some practical considerations on the use of literate programming in statistics....

  1. Cdc42 is not essential for filopodium formation, directed migration, cell polarization, and mitosis in fibroblastoid cells

    DEFF Research Database (Denmark)

    Czuchra, Aleksandra; Wu, Xunwei; Meyer, Hannelore;

    2005-01-01

    of Cdc42 did not affect filopodium or lamellipodium formation and had no significant influence on the speed of directed migration nor on mitosis. Cdc42-deficient cells displayed a more elongated cell shape and had a reduced area. Furthermore, directionality during migration and reorientation of the...

  2. The apical ectodermal ridge of the mouse model of ectrodactyly Dlx5;Dlx6-/- shows altered stratification and cell polarity, which are restored by exogenous Wnt5a ligand.

    Science.gov (United States)

    Conte, Daniele; Garaffo, Giulia; Lo Iacono, Nadia; Mantero, Stefano; Piccolo, Stefano; Cordenonsi, Michelangelo; Perez-Morga, David; Orecchia, Valeria; Poli, Valeria; Merlo, Giorgio R

    2016-02-15

    The congenital malformation split hand/foot (SHFM) is characterized by missing central fingers and dysmorphology or fusion of the remaining ones. Type-1 SHFM is linked to deletions/rearrangements of the DLX5-DLX6 locus and point mutations in the DLX5 gene. The ectrodactyly phenotype is reproduced in mice by the double knockout (DKO) of Dlx5 and Dlx6. During limb development, the apical ectodermal ridge (AER) is a key-signaling center responsible for early proximal-distal growth and patterning. In Dlx5;6 DKO hindlimbs, the central wedge of the AER loses multilayered organization and shows down-regulation of FGF8 and Dlx2. In search for the mechanism, we examined the non-canonical Wnt signaling, considering that Dwnt-5 is a target of distalless in Drosophila and the knockout of Wnt5, Ryk, Ror2 and Vangl2 in the mouse causes severe limb malformations. We found that in Dlx5;6 DKO limbs, the AER expresses lower levels of Wnt5a, shows scattered β-catenin responsive cells and altered basolateral and planar cell polarity (PCP). The addition of Wnt5a to cultured embryonic limbs restored the expression of AER markers and its stratification. Conversely, the inhibition of the PCP molecule c-jun N-terminal kinase caused a loss of AER marker expression. In vitro, the addition of Wnt5a on mixed primary cultures of embryonic ectoderm and mesenchyme was able to confer re-polarization. We conclude that the Dlx-related ectrodactyly defect is associated with the loss of basoapical and PCP, due to reduced Wnt5a expression and that the restoration of the Wnt5a level is sufficient to partially reverts AER misorganization and dysmorphology. PMID:26685160

  3. The apical ectodermal ridge of the mouse model of ectrodactyly Dlx5;Dlx6−/− shows altered stratification and cell polarity, which are restored by exogenous Wnt5a ligand

    Science.gov (United States)

    Conte, Daniele; Garaffo, Giulia; Lo Iacono, Nadia; Mantero, Stefano; Piccolo, Stefano; Cordenonsi, Michelangelo; Perez-Morga, David; Orecchia, Valeria; Poli, Valeria; Merlo, Giorgio R.

    2016-01-01

    The congenital malformation split hand/foot (SHFM) is characterized by missing central fingers and dysmorphology or fusion of the remaining ones. Type-1 SHFM is linked to deletions/rearrangements of the DLX5–DLX6 locus and point mutations in the DLX5 gene. The ectrodactyly phenotype is reproduced in mice by the double knockout (DKO) of Dlx5 and Dlx6. During limb development, the apical ectodermal ridge (AER) is a key-signaling center responsible for early proximal–distal growth and patterning. In Dlx5;6 DKO hindlimbs, the central wedge of the AER loses multilayered organization and shows down-regulation of FGF8 and Dlx2. In search for the mechanism, we examined the non-canonical Wnt signaling, considering that Dwnt-5 is a target of distalless in Drosophila and the knockout of Wnt5, Ryk, Ror2 and Vangl2 in the mouse causes severe limb malformations. We found that in Dlx5;6 DKO limbs, the AER expresses lower levels of Wnt5a, shows scattered β-catenin responsive cells and altered basolateral and planar cell polarity (PCP). The addition of Wnt5a to cultured embryonic limbs restored the expression of AER markers and its stratification. Conversely, the inhibition of the PCP molecule c-jun N-terminal kinase caused a loss of AER marker expression. In vitro, the addition of Wnt5a on mixed primary cultures of embryonic ectoderm and mesenchyme was able to confer re-polarization. We conclude that the Dlx-related ectrodactyly defect is associated with the loss of basoapical and PCP, due to reduced Wnt5a expression and that the restoration of the Wnt5a level is sufficient to partially reverts AER misorganization and dysmorphology. PMID:26685160

  4. Effect of ethanol on pro-apoptotic mechanisms in polarized hepatic cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chronic ethanol consumption is associated with serious and potentially fatal alcohol-related liver injuries such as hepatomegaly, alcoholic hepatitis and cirrhosis. Moreover,it has been documented that the clinical progression of alcohol-induced liver damage may be associated with an increase in hepatocellular death that involves apoptotic mechanisms. Although much information has been learned about the clinical manifestations associated with alcohol-related diseases, the search continues for a better understanding of the molecular and/or cellular mechanisms by which ethanol exerts its deleterious effects such as the induction of pro-apoptotic mechanisms and related cell damaging events. As part of the effort to enhance our understanding of those particular cellular pathways and mechanisms associated with ethanol toxicity, researchers over the years have utilized a variety of model systems. Recently, work has come forth demonstrating the utility of a hybrid cell line (WIF-B) as a cell culture model system for the study of alcohol-associated alterations in hepatocellular mechanisms. Success with such emerging model systems could aid in the development of potential therapeutic treatments for the prevention of alcoholinduced apoptotic cell death that may ultimately serve as a significant target in delaying the onset and/or progression of clinical symptoms of alcohol-mediated liver disease. This review article summarizes the current understanding of ethanol-mediated modifications in cell survival and thus the promotion of pro-apoptotic events with emphasis on analyses made in various experimental model systems, particularly the more recently characterized WIF-B cell system.

  5. Generation of IL-8 and IL-9 Producing CD4+ T Cells Is Affected by Th17 Polarizing Conditions and AHR Ligands

    Directory of Open Access Journals (Sweden)

    Michaela Gasch

    2014-01-01

    Full Text Available The T helper cell subsets Th1, Th2, Th17, and Treg play an important role in immune cell homeostasis, in host defense, and in immunological disorders. Recently, much attention has been paid to Th17 cells which seem to play an important role in the early phase of the adoptive immune response and autoimmune disease. When generating Th17 cells under in vitro conditions the amount of IL-17A producing cells hardly exceeds 20% while the nature of the remaining T cells is poorly characterized. As engagement of the aryl hydrocarbon receptor (AHR has also been postulated to modulate the differentiation of T helper cells into Th17 cells with regard to the IL-17A expression we ask how far do Th17 polarizing conditions in combination with ligand induced AHR activation have an effect on the production of other T helper cell cytokines. We found that a high proportion of T helper cells cultured under Th17 polarizing conditions are IL-8 and IL-9 single producing cells and that AHR activation results in an upregulation of IL-8 and a downregulation of IL-9 production. Thus, we have identified IL-8 and IL-9 producing T helper cells which are subject to regulation by the engagement of the AHR.

  6. Spin-polarized lithium diffusion in a glass hot-vapor cell

    Science.gov (United States)

    Ishikawa, Kiyoshi

    2016-08-01

    We report diffusion coefficients of optically pumped lithium atoms in helium buffer gas. The free-induction decay and the spin-echo signals of ground-state atoms were optically detected in an external magnetic field with the addition of field gradient. Lithium hot vapor was produced in a borosilicate-glass cell at a temperature between 290 and 360°C. The simple setup using the glass cells enabled lithium atomic spectroscopy in a similar way to other alkali-metal atoms and study of the collisional properties of lithium atoms in a hot-vapor phase.

  7. Build them up and break them down: Tight junctions of cell lines expressing typical hepatocyte polarity with a varied repertoire of claudins.

    Science.gov (United States)

    Grosse, Brigitte; Degrouard, Jeril; Jaillard, Danielle; Cassio, Doris

    2013-10-01

    Tight junctions (TJs) of cells expressing simple epithelial polarity have been extensively studied, but less is known about TJs of cells expressing complex polarity. In this paper we analyzed, TJs of four different lines, that form bile canaliculi (BC) and express typical hepatocyte polarity; WIF-B9, 11-3, Can 3-1, Can 10. Striking differences were observed in claudin expression. None of the cell lines produced claudin-1. WIF-B9 and 11-3 expressed only claudin-2 while Can 3-1 and Can 10 expressed claudin-2,-3,-4,-5. TJs of these two classes of lines differed in their ultra-stucture, paracellular permeability, and robustness. Lines expressing a large claudin repertoire, especially Can 10, had complex and efficient TJs, that were maintained when cells were depleted in calcium. Inversely, TJs of WIF-B9 and 11-3 were leaky, permissive and dismantled by calcium depletion. Interestingly, we found that during the polarization process, TJ proteins expressed by all lines were sequentially settled in a specific order: first occludin, ZO-1 and cingulin, then JAM-A and ZO-2, finally claudin-2. Claudins expressed only in Can lines were also sequentially settled: claudin-3 was the first settled. Inhibition of claudin-3 expression delayed BC formation in Can10 and induced the expression of simple epithelial polarity. These results highlight the role of claudins in the settlement and the efficiency of TJs in lines expressing typical hepatocyte polarity. Can 10 seems to be the most promising of these lines because of its claudin repertoire near that of hepatocytes and its capacity to form extended tubular BC sealed by efficient TJs. PMID:24665408

  8. Feline and canine coronaviruses are released from the basolateral side of polarized epithelial LLC-PK1 cells expressing the recombinant feline aminopeptidase-N cDNA

    NARCIS (Netherlands)

    Rossen, J W; Kouame, J; Goedheer, A J; Vennema, H; Rottier, P J

    2001-01-01

    In this study feline (FECV and FIPV) and canine (CCoV) coronavirus entry into and release from polarized porcine epithelial LLC-PK1 cells, stably expressing the recombinant feline aminopeptidase-N cDNA, were investigated. Virus entry appeared to occur preferentially through the apical membrane, simi

  9. The song of lipids and proteins: dynamic lipid-protein interfaces in the regulation of plant cell polarity at different scales

    Czech Academy of Sciences Publication Activity Database

    Sekereš, Juraj; Pleskot, Roman; Pejchar, Přemysl; Žárský, Viktor; Potocký, Martin

    2015-01-01

    Roč. 66, č. 6 (2015), s. 1587-1598. ISSN 0022-0957 R&D Projects: GA ČR GA13-19073S Grant ostatní: GA MŠk(CZ) LO1417 Institutional support: RVO:61389030 Keywords : Cell polarity * endocytosis * exocytosis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.526, year: 2014

  10. Junctional adhesion molecule-C (JAM-C) regulates polarized neutrophil transendothelial cell migration in vivo

    Science.gov (United States)

    Woodfin, Abigail; Voisin, Mathieu-Benoit; Beyrau, Martina; Colom, Bartomeu; Caille, Dorothée; Diapouli, Frantzeska-Maria; Nash, Gerard B; Chavakis, Triantafyllos; Albelda, Steven M.; Rainger, G Ed; Meda, Paolo; Imhof, Beat A.; Nourshargh, Sussan

    2011-01-01

    Neutrophil migration into inflamed tissues is a fundamental component of innate immunity. A decisive step in this process is the polarised migration of blood neutrophils through endothelial cells (ECs) lining the venular lumen (transendothelial cell migration; TEM) in a luminal to abluminal direction. Using real-time confocal imaging we report that neutrophils can exhibit disrupted polarised TEM (“hesitant” and “reverse”) in vivo. These events were noted in inflammation following ischemia-reperfusion injury, characterised by reduced expression of junctional adhesion molecule C (JAM-C) from EC junctions, and were enhanced by EC JAM-C blockade or genetic deletion. The results identify JAM-C as a key regulator of polarised neutrophil TEM in vivo and suggest that reverse TEM neutrophils can contribute to dissemination of systemic inflammation. PMID:21706006

  11. The PDZ Protein Na+/H+ Exchanger Regulatory Factor-1 (NHERF1) Regulates Planar Cell Polarity and Motile Cilia Organization

    Science.gov (United States)

    Stolz, Donna B.; Tsang, Michael; Friedman, Peter A.; Romero, Guillermo

    2016-01-01

    Directional flow of the cerebrospinal fluid requires coordinated movement of the motile cilia of the ependymal epithelium that lines the cerebral ventricles. Here we report that mice lacking the Na+/H+ Exchanger Regulatory Factor 1 (NHERF1/Slc9a3r1, also known as EBP50) develop profound communicating hydrocephalus associated with fewer and disorganized ependymal cilia. Knockdown of NHERF1/slc9a3r1 in zebrafish embryos also causes severe hydrocephalus of the hindbrain and impaired ciliogenesis in the otic vesicle. Ultrastructural analysis did not reveal defects in the shape or organization of individual cilia. Similar phenotypes have been described in animals with deficiencies in Wnt signaling and the Planar Cell Polarity (PCP) pathway. We show that NHERF1 binds the PCP core genes Frizzled (Fzd) and Vangl. We further show that NHERF1 assembles a ternary complex with Fzd4 and Vangl2 and promotes translocation of Vangl2 to the plasma membrane, in particular to the apical surface of ependymal cells. Taken together, these results strongly support an important role for NHERF1 in the regulation of PCP signaling and the development of functional motile cilia. PMID:27055101

  12. Polarized exocyst-mediated vesicle fusion directs intracellular lumenogenesis within the C. elegans excretory cell

    OpenAIRE

    Armenti, Stephen T.; Chan, Emily; Nance, Jeremy

    2014-01-01

    Lumenogenesis of small seamless tubes occurs through intracellular membrane growth and directed vesicle fusion events. Within the C. elegans excretory cell, which forms seamless intracellular tubes (canals) that mediate osmoregulation, lumens grow in length and diameter when vesicles fuse with the expanding lumenal surface. Here, we show that lumenal vesicle fusion depends on the small GTPase RAL-1, which localizes to vesicles and acts through the exocyst vesicle-tethering complex. Loss of ei...

  13. Studies on polar cell wall growth and antibiotic susceptibility of Corynebacterium glutamicum

    OpenAIRE

    Sieger, Boris

    2015-01-01

    Corynebacterium glutamicum is a Gram positive soil bacterium with high industrial importance in ton scale production of amino acids. Apart from that, it becomes more and more important for medical studies, where it serves as model organism due to its close relation to bacteria causing several pathogens such as tuberculosis, diphtheria and leprosy. C. glutamicum, like Mycobacterium tuberculosis, has a distinct cell wall which is composed of a peptidoglycan layer (murein) with covalently bo...

  14. Lipid Droplet Accumulation and Impaired Fat Efflux in Polarized Hepatic Cells: Consequences of Ethanol Metabolism

    Directory of Open Access Journals (Sweden)

    Benita L. McVicker

    2012-01-01

    Full Text Available Steatosis, an early manifestation in alcoholic liver disease, is associated with the accumulation of hepatocellular lipid droplets (LDs. However, the role ethanol metabolism has in LD formation and turnover remains undefined. Here, we assessed LD dynamics following ethanol and oleic acid treatment to ethanol-metabolizing WIF-B cells (a hybrid of human fibroblasts (WI 38 and Fao rat hepatoma cells. An OA dose-dependent increase in triglyceride and stained lipids was identified which doubled (P<0.05 in the presence of ethanol. This effect was blunted with the inclusion of an alcohol metabolism inhibitor. The ethanol/ OA combination also induced adipophilin, LD coat protein involved in the attenuation of lipolysis. Additionally, ethanol treatment resulted in a significant reduction in lipid efflux. These data demonstrate that the metabolism of ethanol in hepatic cells is related to LD accumulation, impaired fat efflux, and enhancements in LD-associated proteins. These alterations in LD dynamics may contribute to ethanol-mediated defects in hepatocellular LD regulation and the formation of steatosis.

  15. The Balance Between the Novel Protein Target of Wingless and the Drosophila Rho-Associated Kinase Pathway Regulates Planar Cell Polarity in the Drosophila Wing

    OpenAIRE

    Chung, SeYeon; Kim, Sangjoon; Yoon, Jeongsook; Adler, Paul N.; Yim, Jeongbin

    2007-01-01

    Planar cell polarity (PCP) signaling is mediated by the serpentine receptor Frizzled (Fz) and transduced by Dishevelled (Dsh). Wingless (Wg) signaling utilizes Drosophila Frizzled 2 (DFz2) as a receptor and also requires Dsh for transducing signals to regulate cell proliferation and differentiation in many developmental contexts. Distinct pathways are activated downstream of Dsh in Wg- and Fz-signaling pathways. Recently, a number of genes, which have essential roles as downstream components ...

  16. Explorations in statistics: statistical facets of reproducibility.

    Science.gov (United States)

    Curran-Everett, Douglas

    2016-06-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This eleventh installment of Explorations in Statistics explores statistical facets of reproducibility. If we obtain an experimental result that is scientifically meaningful and statistically unusual, we would like to know that our result reflects a general biological phenomenon that another researcher could reproduce if (s)he repeated our experiment. But more often than not, we may learn this researcher cannot replicate our result. The National Institutes of Health and the Federation of American Societies for Experimental Biology have created training modules and outlined strategies to help improve the reproducibility of research. These particular approaches are necessary, but they are not sufficient. The principles of hypothesis testing and estimation are inherent to the notion of reproducibility in science. If we want to improve the reproducibility of our research, then we need to rethink how we apply fundamental concepts of statistics to our science. PMID:27231259

  17. Experimental reproducibility analysis in DU hydriding

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Daeseo; Park, Jongcheol; Chung, Hongsuk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. For the storage, supply, and recovery of hydrogen isotopes, depleted uranium (DU) has been extensively proposed. To develop nuclear fusion technology, it will be necessary to store and supply hydrogen isotopes needed for Tokamak operation. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. The experimental reproducibility of apparatus was acceptable for all the experiments. The experimental reproducibility of tank pressure on DU hydriding was analyzed. As the hydriding performs, the tank pressure showed decreasing trend. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. As the hydriding performs, the bed temperatures increased up to maximum temperature with exothermic reaction and then they showed decreasing trend. The experimental reproducibility of apparatus was acceptable for all the experiments.

  18. Combined TLR2 and TLR4 ligation in the context of bacterial or helminth extracts in human monocyte derived dendritic cells: Molecular correlates for Th1/Th2 polarization

    NARCIS (Netherlands)

    Riet, E. van; Everts, B.; Retra, K.; Phylipsen, M.; Hellemond, J.J. van; Tielens, A.G.M.; Kleij, D. van der; Hartgers, F.C.; Yazdanbakhsh, M.

    2009-01-01

    Background: Recognition of pathogens by dendritic cells (DCs) through interaction with pattern recognition receptors, including Toll like receptors (TLR), is crucial for the initiation of appropriate polarized T helper (Th) cell responses. Yet, the characteristics and differences in molecular profil

  19. Examination of reproducibility in microbiological degredation experiments

    DEFF Research Database (Denmark)

    Sommer, Helle Mølgaard; Spliid, Henrik; Holst, Helle;

    1998-01-01

    Experimental data indicate that certain microbiological degradation experiments have a limited reproducibility. Nine identical batch experiments were carried out on 3 different days to examine reproducibility. A pure culture, isolated from soil, grew with toluene as the only carbon and energy...... source. Toluene was degraded under aerobic conditions at a constant temperature of 28 degreesC. The experiments were modelled by a Monod model - extended to meet the air/liquid system, and the parameter values were estimated using a statistical nonlinear estimation procedure. Model reduction analysis....... The limited reproducibility may be caused by variability in the preculture, or more precisely, variations in the physiological state of the bacteria in the precultures just before used as inoculum....

  20. Escherichia coli isolated from a Crohn's disease patient adheres, invades, and induces inflammatory responses in polarized intestinal epithelial cells.

    Science.gov (United States)

    Eaves-Pyles, Tonyia; Allen, Christopher A; Taormina, Joanna; Swidsinski, Alexander; Tutt, Christopher B; Jezek, G Eric; Islas-Islas, Martha; Torres, Alfredo G

    2008-07-01

    Inflammatory diseases of the intestinal tract are a major health concern both in the United States and around the world. Evidence now suggests that a new category of Escherichia coli, designated Adherent Invasive E. coli (AIEC) is highly prevalent in Crohn's Disease (CD) patients. AIEC strains have been shown to colonize and adhere to intestinal epithelial cells (IEC). However, the role AIEC strains play in the induction of an inflammatory response is not known. Therefore, we examined several E. coli strains (designated LF82, O83:H1, 6604 and 6655) that were isolated from CD patients for their ability to induce inflammation in two IEC, Caco-2BBe and T-84 cells. Results showed that each strain had varying abilities to adhere to and invade IEC as well as induced cytokine secretion from polarized IEC. However, E. coli O83:H1 displayed the best characteristics of AIEC strains as compared to the prototype AIEC strain LF82, inducing cytokine secretion from IEC and promoting immune cell migration through IEC. Upon further analysis, E. coli O83:H1 did not harbor virulence genes present in known pathogenic intestinal organisms. Further characterization of E. coli O83:H1 virulence determinants showed that a non-flagellated O83:H1 strain significantly decreased the organism's ability to adhere to and invade both IEC and elicit IEC cytokine secretion compared to the wild type and complemented strains. These findings demonstrate that E. coli O83:H1 possesses the characteristics of the AIEC LF82 strain that may contribute to the low-grade, chronic inflammation observed in Crohn's disease. PMID:17900983

  1. Reproducibility of operator processing for radiation dosimetry

    International Nuclear Information System (INIS)

    Reproducibility of operator processing for radiation dose and biological half-life was assessed for radioimmunotherapy. Mean coefficient of variation for intra-operator consecutive processing and for inter-operator processing was less than 15% for all tissues. The mean coefficient of variation for intra-operator processing over 2 wk or inter-operator processing comparing an experienced and less experienced operator was generally greater, and particularly so for tumors. Satisfactory reproducibility was achievable using visual determination of regions of interests after 80 h of training

  2. Reproducibility of operator processing for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sui Shen; DeNardo, Gerald L.; DeNardo, Sally J.; Aina, Yuan; DeNardo, Diane A.; Lamborn, Kathleen R

    1997-01-01

    Reproducibility of operator processing for radiation dose and biological half-life was assessed for radioimmunotherapy. Mean coefficient of variation for intra-operator consecutive processing and for inter-operator processing was less than 15% for all tissues. The mean coefficient of variation for intra-operator processing over 2 wk or inter-operator processing comparing an experienced and less experienced operator was generally greater, and particularly so for tumors. Satisfactory reproducibility was achievable using visual determination of regions of interests after 80 h of training.

  3. Archiving Reproducible Research with R and Dataverse

    DEFF Research Database (Denmark)

    Leeper, Thomas

    2014-01-01

    Reproducible research and data archiving are increasingly important issues in research involving statistical analyses of quantitative data. This article introduces the dvn package, which allows R users to publicly archive datasets, analysis files, codebooks, and associated metadata in Dataverse...... Network online repositories, an open-source data archiving project sponsored by Harvard University. In this article I review the importance of data archiving in the context of reproducible research, introduce the Dataverse Network, explain the implementation of the dvn package, and provide example code...... for archiving and releasing data using the package....

  4. Apico-basal polarity complex and cancer

    Indian Academy of Sciences (India)

    Mohammed Khursheed; Murali Dharan Bashyam

    2014-03-01

    Apico-basal polarity is a cardinal molecular feature of adult eukaryotic epithelial cells and appears to be involved in several key cellular processes including polarized cell migration and maintenance of tissue architecture. Epithelial cell polarity is maintained by three well-conserved polarity complexes, namely, PAR, Crumbs and SCRIB. The location and interaction between the components of these complexes defines distinct structural domains of epithelial cells. Establishment and maintenance of apico-basal polarity is regulated through various conserved cell signalling pathways including TGF, Integrin and WNT signalling. Loss of cell polarity is a hallmark for carcinoma, and its underlying molecular mechanism is beginning to emerge from studies on model organisms and cancer cell lines. Moreover, deregulated expression of apico-basal polarity complex components has been reported in human tumours. In this review, we provide an overview of the apico-basal polarity complexes and their regulation, their role in cell migration, and finally their involvement in carcinogenesis.

  5. PURIFIED POLAR POLYFLUORENE FOR LIGHT-EMITTING DIODES AND LIGHT-EMITTING ELECTROCHEMICAL CELLS

    Institute of Scientific and Technical Information of China (English)

    Ming-liang Sun; Cheng-mei Zhong; Feng Li; Qi-bing Pei

    2012-01-01

    Conjugated ployfluorene with 2-(2-(2-methoxyethoxy)ethoxy)ethyl groups (EO-PF) is prepared by the palladiumcatalyzed Suzuki coupling reaction.The polymer is purified carefully by a simple chemical procedure.The inductively coupled plasma (ICP) test shows palladium-catalyst in the polymer can be removed by this procedure.The thermal properties,electrochemical properties,UV-Vis absorption properties,photoluminescence properties and electroluminescent properties of the polymer without (EO-PF1) or with purification (EO-PF2) are studied.EO-PF2 shows better PL CIE coordinates in THF solutions as blue light-emitting materials and better photoluminescence stability in thin solid films.Polymer light emitting diodes and electrochemical cells based on EO-PF2 exhibit somewhat improved optoelectronic performance than control devices of EO-PF1.

  6. Stability and error analysis of the polarization estimation inverse problem for microbial fuel cells

    International Nuclear Information System (INIS)

    Determining parameters which describe the performance of a microbial fuel cell requires the solution of an inverse problem. Two formulations have been presented in the literature: a convolutional approach or a direct quadrature approach. A complete study and analysis of the direct quadrature method, which leads to two systems for the unknown signal given measured complex data, known as the distribution function of relaxation times, is presented. A theoretical analysis justifies the minimal range of integration that is appropriate for the quadrature and suggests that the systems should be combined giving an overdetermined system that is not well posed but not as ill-posed as either system considered separately. All measures of ill-posedness support using the combined data when the level of error in both components of the complex measurements is equivalent. Tikhonov regularization for the filtered singular value and truncated singular value decomposition are used to find solutions of the underlying model system. Given such solutions the application requires the determination of the model parameters that define the signal, among which are the location and peaks of the individual processes of the cell. A nonlinear data fitting approach is presented which consistently estimates these parameters. Simulations support the use of the combined systems for finding the underlying distribution function of relaxation times and the subsequent nonlinear data fitting to these curves. The approach is also illustrated for measured practical data, demonstrating that without the theoretical analysis incorrect conclusions on the underlying physical system would arise. This work justifies the use of Tikhonov regularization combined with nonlinear data fitting for finding reliable solutions for the specific model, when the signal is comprised of a mixture of signals from a small number of processes. (paper)

  7. Lethal(2)giant larvae is required in the follicle cells for formation of the initial AP asymmetry and the oocyte polarity during Drosophila oogenesis

    Institute of Scientific and Technical Information of China (English)

    Qi Li; Tianchi Xin; Wenlian Chen; Mingwei Zhu; Mingfa Li

    2008-01-01

    The intricately regulated differentiation of the somatic follicle cell lineages into distinct subpopulations with specific functions plays an essential role in Drosophila egg development. At early oogenesis, induction of the stalk cells generates the first anteroposterior (AP) asymmetry in the egg chamber by inducing the posterior localization of the oocyte. Later, the properly specified posterior follicle cells signal to polarize the oocyte along the AP and dorsoventral (DV) axes at mid-oogenesis. Here, we show that lethal(2)giant larvae (Igt), a Drosophila tumor suppressor gene, is required in the follicle cells for the differentiation of both stalk cells and posterior follicle cells. Loss-of-function mutations in Igl cause oocyte mispositioning in the younger one of the fused chambers, due to lack of the stalk. Removal of Igl function from the posterior follicle cells using the FLP/FRT system results in loss of the oocyte polarity that is elicited by the failure of those posterior cells to differentiate normally. Thus, we provide the first demonstration that Igl is implicated in the formation of the initial AP asymmetry and the patterning of the AP and DV axes in the oocyte by acting in the specification of a subset of somatic follicle cells.

  8. Estimating the reproducibility of psychological science

    NARCIS (Netherlands)

    Anderson, Joanna E.; Aarts, Alexander A.; Anderson, Christopher J.; Attridge, Peter R.; Attwood, Angela; Axt, Jordan; Babel, Molly; Bahník, Štěpán; Baranski, Erica; Barnett-Cowan, Michael; Bartmess, Elizabeth; Beer, Jennifer; Bell, Raoul; Bentley, Heather; Beyan, Leah; Binion, Grace; Borsboom, Denny; Bosch, Annick; Bosco, Frank A.; Bowman, Sara D.; Brandt, Mark J.; Braswell, Erin; Brohmer, Hilmar; Brown, Benjamin T.; Brown, Kristina; Brüning, Jovita; Calhoun-Sauls, Ann; Callahan, Shannon P.; Chagnon, Elizabeth; Chandler, Jesse; Chartier, Christopher R.; Cheung, Felix; Christopherson, Cody D.; Cillessen, Linda; Clay, Russ; Cleary, Hayley; Cloud, Mark D.; Conn, Michael; Cohoon, Johanna; Columbus, Simon; Cordes, Andreas; Costantini, Giulio; Alvarez, Leslie D Cramblet; Cremata, Ed; Crusius, Jan; DeCoster, Jamie; DeGaetano, Michelle A.; Penna, Nicolás Delia; Den Bezemer, Bobby; Deserno, Marie K.; Devitt, Olivia; Dewitte, Laura; Dobolyi, David G.; Dodson, Geneva T.; Donnellan, M. Brent; Donohue, Ryan; Dore, Rebecca A.; Dorrough, Angela; Dreber, Anna; Dugas, Michelle; Dunn, Elizabeth W.; Easey, Kayleigh; Eboigbe, Sylvia; Eggleston, Casey; Embley, Jo; Epskamp, Sacha; Errington, Timothy M.; Estel, Vivien; Farach, Frank J.; Feather, Jenelle; Fedor, Anna; Fernández-Castilla, Belén; Fiedler, Susann; Field, James G.; Fitneva, Stanka A.; Flagan, Taru; Forest, Amanda L.; Forsell, Eskil; Foster, Joshua D.; Frank, Michael C.; Frazier, Rebecca S.; Fuchs, Heather; Gable, Philip; Galak, Jeff; Galliani, Elisa Maria; Gampa, Anup; Garcia, Sara; Gazarian, Douglas; Gilbert, Elizabeth; Giner-Sorolla, Roger; Glöckner, Andreas; Goellner, Lars; Goh, Jin X.; Goldberg, Rebecca; Goodbourn, Patrick T.; Gordon-McKeon, Shauna; Gorges, Bryan; Gorges, Jessie; Goss, Justin; Graham, Jesse; Grange, James A.; Gray, Jeremy; Hartgerink, Chris; Hartshorne, Joshua; Hasselman, Fred; Hayes, Timothy; Heikensten, Emma; Henninger, Felix; Hodsoll, John; Holubar, Taylor; Hoogendoorn, Gea; Humphries, Denise J.; Hung, Cathy O Y; Immelman, Nathali; Irsik, Vanessa C.; Jahn, Georg; Jäkel, Frank; Jekel, Marc; Johannesson, Magnus; Johnson, Larissa G.; Johnson, David J.; Johnson, Kate M.; Johnston, William J.; Jonas, Kai; Joy-Gaba, Jennifer A.; Kappes, Heather Barry; Kelso, Kim; Kidwell, Mallory C.; Kim, Seung Kyung; Kirkhart, Matthew; Kleinberg, Bennett; Knežević, Goran; Kolorz, Franziska Maria; Kossakowski, Jolanda J.; Krause, Robert Wilhelm; Krijnen, Job; Kuhlmann, Tim; Kunkels, Yoram K.; Kyc, Megan M.; Lai, Calvin K.; Laique, Aamir; Lakens, Daniël; Lane, Kristin A.; Lassetter, Bethany; Lazarević, Ljiljana B.; Le Bel, Etienne P.; Lee, Key Jung; Lee, Minha; Lemm, Kristi; Levitan, Carmel A.; Lewis, Melissa; Lin, Lin; Lin, Stephanie; Lippold, Matthias; Loureiro, Darren; Luteijn, Ilse; MacKinnon, Sean; Mainard, Heather N.; Marigold, Denise C.; Martin, Daniel P.; Martinez, Tylar; Masicampo, E. J.; Matacotta, Josh; Mathur, Maya; May, Michael; Mechin, Nicole; Mehta, Pranjal; Meixner, Johannes; Melinger, Alissa; Miller, Jeremy K.; Miller, Mallorie; Moore, Katherine; Möschl, Marcus; Motyl, Matt; Müller, Stephanie M.; Munafo, Marcus; Neijenhuijs, Koen I.; Nervi, Taylor; Nicolas, Gandalf; Nilsonne, Gustav; Nosek, Brian A.; Nuijten, Michèle B.; Olsson, Catherine; Osborne, Colleen; Ostkamp, Lutz; Pavel, Misha; Penton-Voak, Ian S.; Perna, Olivia; Pernet, Cyril; Perugini, Marco; Pipitone, R. Nathan; Pitts, Michael; Plessow, Franziska; Prenoveau, Jason M.; Rahal, Rima Maria; Ratliff, Kate A.; Reinhard, David; Renkewitz, Frank; Ricker, Ashley A.; Rigney, Anastasia; Rivers, Andrew M.; Roebke, Mark; Rutchick, Abraham M.; Ryan, Robert S.; Sahin, Onur; Saide, Anondah; Sandstrom, Gillian M.; Santos, David; Saxe, Rebecca; Schlegelmilch, René; Schmidt, Kathleen; Scholz, Sabine; Seibel, Larissa; Selterman, Dylan Faulkner; Shaki, Samuel; Simpson, William B.; Sinclair, H. Colleen; Skorinko, Jeanine L M; Slowik, Agnieszka; Snyder, Joel S.; Soderberg, Courtney; Sonnleitner, Carina; Spencer, Nick; Spies, Jeffrey R.; Steegen, Sara; Stieger, Stefan; Strohminger, Nina; Sullivan, Gavin B.; Talhelm, Thomas; Tapia, Megan; Te Dorsthorst, Anniek; Thomae, Manuela; Thomas, Sarah L.; Tio, Pia; Traets, Frits; Tsang, Steve; Tuerlinckx, Francis; Turchan, Paul; Valášek, Milan; Van't Veer, Anna E.; Van Aert, Robbie; Van Assen, Marcel; Van Bork, Riet; Van De Ven, Mathijs; Van Den Bergh, Don; Van Der Hulst, Marije; Van Dooren, Roel; Van Doorn, Johnny; Van Renswoude, Daan R.; Van Rijn, Hedderik; Vanpaemel, Wolf; Echeverría, Alejandro Vásquez; Vazquez, Melissa; Velez, Natalia; Vermue, Marieke; Verschoor, Mark; Vianello, Michelangelo; Voracek, Martin; Vuu, Gina; Wagenmakers, Eric Jan; Weerdmeester, Joanneke; Welsh, Ashlee; Westgate, Erin C.; Wissink, Joeri; Wood, Michael; Woods, Andy; Wright, Emily; Wu, Sining; Zeelenberg, Marcel; Zuni, Kellylynn

    2015-01-01

    Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Rep

  9. Estimating the reproducibility of psychological science

    NARCIS (Netherlands)

    Aarts, Alexander A.; Anderson, Joanna E.; Anderson, Christopher J.; Attridge, Peter R.; Attwood, Angela; Axt, Jordan; Babel, Molly; Bahnik, Stepan; Baranski, Erica; Barnett-Cowan, Michael; Bartmess, Elizabeth; Beer, Jennifer; Bell, Raoul; Bentley, Heather; Beyan, Leah; Binion, Grace; Borsboom, Denny; Bosch, Annick; Bosco, Frank A.; Bowman, Sara D.; Brandt, Mark J.; Braswell, Erin; Brohmer, Hilmar; Brown, Benjamin T.; Brown, Kristina; Bruening, Jovita; Calhoun-Sauls, Ann; Chagnon, Elizabeth; Callahan, Shannon P.; Chandler, Jesse; Chartier, Christopher R.; Cheung, Felix; Cillessen, Linda; Christopherson, Cody D.; Clay, Russ; Cleary, Hayley; Cloud, Mark D.; Cohn, Michael; Cohoon, Johanna; Columbus, Simon; Cordes, Andreas; Costantini, Giulio; Alvarez, Leslie D. Cramblet; Cremata, Ed; Crusius, Jan; DeCoster, Jamie; DeGaetano, Michelle A.; Della Penna, Nicolas; den Bezemer, Bobby; Deserno, Marie K.; Devitt, Olivia; Dewitte, Laura; Dobolyi, David G.; Dodson, Geneva T.; Donnellan, M. Brent; Donohue, Ryan; Dore, Rebecca A.; Dorrough, Angela; Dreber, Anna; Dugas, Michelle; Dunn, Elizabeth W.; Easey, Kayleigh; Eboigbe, Sylvia; Eggleston, Casey; Embley, Jo; Epskamp, Sacha; Errington, Timothy M.; Estel, Vivien; Farach, Frank J.; Feather, Jenelle; Fedor, Anna; Fernandez-Castilla, Belen; Fiedler, Susann; Field, James G.; Fitneva, Stanka A.; Flagan, Taru; Forest, Amanda L.; Forsell, Eskil; Foster, Joshua D.; Frank, Michael C.; Frazier, Rebecca S.; Fuchs, Heather; Gable, Philip; Galak, Jeff; Galliani, Elisa Maria; Gampa, Anup; Garcia, Sara; Gazarian, Douglas; Gilbert, Elizabeth; Giner-Sorolla, Roger; Gloeckner, Andreas; Goellner, Lars; Goh, Jin X.; Goldberg, Rebecca; Goodbourn, Patrick T.; Gordon-McKeon, Shauna; Gorges, Bryan; Gorges, Jessie; Goss, Justin; Graham, Jesse; Grange, James A.; Gray, Jeremy; Hartgerink, Chris; Hartshorne, Joshua; Hasselman, Fred; Hayes, Timothy; Heikensten, Emma; Henninger, Felix; Hodsoll, John; Holubar, Taylor; Hoogendoorn, Gea; Humphries, Denise J.; Hung, Cathy O. -Y.; Immelman, Nathali; Irsik, Vanessa C.; Jahn, Georg; Jaekel, Frank; Jekel, Marc; Johannesson, Magnus; Johnson, Larissa G.; Johnson, David J.; Johnson, Kate M.; Johnston, William J.; Jonas, Kai; Joy-Gaba, Jennifer A.; Kappes, Heather Barry; Kelso, Kim; Kidwell, Mallory C.; Kim, Seung Kyung; Kirkhart, Matthew; Kleinberg, Bennett; Knezevic, Goran; Kolorz, Franziska Maria; Kossakowski, Jolanda J.; Krause, Robert Wilhelm; Krijnen, Job; Kuhlmann, Tim; Kunkels, Yoram K.; Kyc, Megan M.; Lai, Calvin K.; Laique, Aamir; Lakens, Daniel; Lane, Kristin A.; Lassetter, Bethany; Lazarevic, Ljiljana B.; LeBel, Etienne P.; Lee, Key Jung; Lee, Minha; Lemm, Kristi; Levitan, Carmel A.; Lewis, M.; Lin, Lin; Lin, Stephanie; Lippold, Matthias; Loureiro, Darren; Luteijn, Ilse; Mackinnon, Sean; Mainard, Heather N.; Marigold, Denise C.; Martin, Daniel P.; Martinez, Tylar; Masicampo, E. J.; Matacotta, Josh; Mathur, Maya; May, Michael; Mechin, Nicole; Mehta, Pranjal; Meixner, Johannes; Melinger, Alissa; Miller, Jeremy K.; Miller, Mallorie; Moore, Katherine; Moeschl, Marcus; Motyl, Matt; Mueller, Stephanie M.; Munafo, Marcus; Neijenhuijs, Koen I.; Nervi, Taylor; Nicolas, Gandalf; Nilsonne, Gustav; Nosek, Brian A.; Nuijten, Michele B.; Olsson, Catherine; Osborne, Colleen; Ostkamp, Lutz; Pavel, Misha; Penton-Voak, Ian S.; Perna, Olivia; Pernet, Cyril; Perugini, Marco; Pipitone, R. Nathan; Pitts, Michael; Plessow, Franziska; Prenoveau, Jason M.; Rahal, Rima-Maria; Ratliff, Kate A.; Reinhard, David; Renkewitz, Frank; Ricker, Ashley A.; Rigney, Anastasia; Rivers, Andrew M.; Roebke, Mark; Rutchick, Abraham M.; Ryan, Robert S.; Sahin, Onur; Saide, Anondah; Sandstrom, Gillian M.; Santos, David; Saxe, Rebecca; Schmidt, Kathleen; Schlegelmilch, Rene; Seibel, Larissa; Scholz, Sabine; Selterman, Dylan Faulkner; Shaki, Samuel; Simpson, William B.; Sinclair, H. Colleen; Skorinko, Jeanine L. M.; Slowik, Agnieszka; Snyder, Joel S.; Soderberg, Courtney; Sonnleitner, Carina; Spencer, Nick; Spies, Jeffrey R.; Steegen, Sara; Stieger, Stefan; Strohminger, Nina; Sullivan, Gavin B.; Talhelm, Thomas; Tapia, Megan; te Dorsthorst, Anniek; Thomae, Manuela; Thomas, Sarah L.; Tio, Pia; Traets, Frits; Tsang, Steve; Tuerlinckx, Francis; Turchan, Paul; Valasek, Milan; van 't Veer, Anna E.; Van Aert, Robbie; van Assen, M.A.L.M.; van Bork, Riet; van de Ven, Mathijs; van den Bergh, Don; van der Hulst, Marije; van Dooren, Roel; van Doorn, Johnny; van Renswoude, Daan R.; van Rijn, Hedderik; Vanpaemel, Wolf; Echeverria, Alejandro Vasquez; Vazquez, Melissa; Velez, Natalia; Vermue, Marieke; Verschoor, Mark; Vianello, Michelangelo; Voracek, Martin; Vuu, Gina; Wagenmakers, Eric-Jan; Weerdmeester, Joanneke; Welsh, Ashlee; Westgate, Erin C.; Wissink, Joeri; Wood, Michael; Woods, Andy; Wright, Emily; Wu, Sining; Zeelenberg, Marcel; Zuni, Kellylynn

    2015-01-01

    INTRODUCTION Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. Scientific claims should not gain credence because of the status or authority of their originator but by the replicability of their supporting evidence. Even research

  10. Uniform and reproducible stirring in a microbioreactor

    DEFF Research Database (Denmark)

    Bolic, Andrijana; Eliasson Lantz, Anna; Rottwitt, Karsten;

    role in achieving successful cultivations by promoting uniform process conditions and – for aerobic cultivations – a high oxygen transfer rate. In this contribution, the development of a suitable, reliable and reproducible stirrer in a microbioreactor for batch and continuous cultivation of S...

  11. TGF-β3-induced miR-494 inhibits macrophage polarization via suppressing PGE2 secretion in mesenchymal stem cells.

    Science.gov (United States)

    Zhao, Guangfeng; Miao, Huishuang; Li, Xiujun; Chen, Shiwen; Hu, Yali; Wang, Zhiqun; Hou, Yayi

    2016-06-01

    Abnormal macrophage polarization at the maternal-fetal interface may contribute to the development of Preeclampsia (PE). The reason why macrophage polarization changed in PE is still unclear. Decidual mesenchymal stem cells (dMSCs) could regulate macrophage polarization. However, miRNA in dMSCs of PE were maladjusted. Therefore, we speculated that miRNA may affect dMSC-regulated macrophage polarization. In this study, we found that miR-494-overexpressed dMSCs inhibit M2 macrophage polarization and this inhibitory effect is mediated by miR-494-reduced PGE2 secretion. Furthermore, we proved that miR-494 is induced by TGF-β3. In summary, our findings suggest that the high expression of TGF-β3 in PE decidua stimulates miR-494 in dMSCs and attenuates the regulation of MSC switching the macrophage toward M2 type, contributing to an immune imbalance at maternal-fetal interface. PMID:27149081

  12. ITK: Enabling Reproducible Research and Open Science

    Directory of Open Access Journals (Sweden)

    Matthew Michael McCormick

    2014-02-01

    Full Text Available Reproducibility verification is essential to the practice of the scientific method. Researchers report their findings, which are strengthened as other independent groups in the scientific community share similar outcomes. In the many scientific fields where software has become a fundamental tool for capturing and analyzing data, this requirement of reproducibility implies that reliable and comprehensive software platforms and tools should be made available to the scientific community. The tools will empower them and the public to verify, through practice, the reproducibility of observations that are reported in the scientific literature.Medical image analysis is one of the fields in which the use of computational resources, both software and hardware, are an essential platform for performing experimental work. In this arena, the introduction of the Insight Toolkit (ITK in 1999 has transformed the field and facilitates its progress by accelerating the rate at which algorithmic implementations are developed, tested, disseminated and improved. By building on the efficiency and quality of open source methodologies, ITK has provided the medical image community with an effective platform on which to build a daily workflow that incorporates the true scientific practices of reproducibility verification.This article describes the multiple tools, methodologies, and practices that the ITK community has adopted, refined, and followed during the past decade, in order to become one of the research communities with the most modern reproducibility verification infrastructure. For example, 207 contributors have created over 2400 unit tests that provide over 84% code line test coverage. The Insight Journal, an open publication journal associated with the toolkit, has seen over 360,000 publication downloads. The median normalized closeness centrality, a measure of knowledge flow, resulting from the distributed peer code review system was high, 0.46.

  13. Introduction of the Six Major Genomic Deletions of Modified Vaccinia Virus Ankara (MVA) into the Parental Vaccinia Virus Is Not Sufficient To Reproduce an MVA-Like Phenotype in Cell Culture and in Mice▿

    OpenAIRE

    Meisinger-Henschel, Christine; Späth, Michaela; Lukassen, Susanne; Wolferstätter, Michael; Kachelriess, Heike; Baur, Karen; Dirmeier, Ulrike; Wagner, Markus; Chaplin, Paul; Suter, Mark; Hausmann, Jürgen

    2010-01-01

    Modified vaccinia virus Ankara (MVA) has a highly restricted host range in cell culture and is apathogenic in vivo. MVA was derived from the parental chorioallantois vaccinia virus Ankara (CVA) by more than 570 passages in chicken embryo fibroblast (CEF) cells. During CEF cell passaging, six major deletions comprising 24,668 nucleotides occurred in the CVA genome. We have cloned both the MVA and the parental CVA genome as bacterial artificial chromosomes (BACs) and have sequentially introduce...

  14. Polar biophenolics in sweet potato greens extract synergize to inhibit prostate cancer cell proliferation and in vivo tumor growth.

    Science.gov (United States)

    Gundala, Sushma R; Yang, Chunhua; Lakshminarayana, N; Asif, Ghazia; Gupta, Meenakshi V; Shamsi, Shahab; Aneja, Ritu

    2013-09-01

    Polyphenolic phytochemicals present in fruits and vegetables indisputably confer anticancer benefits upon regular consumption. Recently, we demonstrated the growth-inhibitory and apoptosis-inducing properties of polyphenol-rich sweet potato greens extract (SPGE) in cell culture and in vivo prostate cancer xenograft models. However, the bioactive constituents remain elusive. Here, we report a bioactivity-guided fractionation of SPGE based upon differential solvent polarity using chromatographic techniques that led to the identification of a remarkably active polyphenol-enriched fraction, F5, which was ~100-fold more potent than the parent extract as shown by IC50 measurements in human prostate cancer cells. High-performance liquid chromatography-ultraviolet and mass spectrometric analyses of the seven SPGE fractions suggested varying abundance of the major phenols, quinic acid (QA), caffeic acid, its ester chlorogenic acid, and isochlorogenic acids, 4,5-di-CQA, 3,5-di-CQA and 3,4-di-CQA, with a distinct composition of the most active fraction, F5. Subfractionation of F5 resulted in loss of bioactivity, suggesting synergistic interactions among the constituent phytochemicals. Quantitative analyses revealed a ~2.6- and ~3.6-fold enrichment of QA and chlorogenic acid, respectively, in F5 and a definitive ratiometric relationship between the isochlorogenic acids. Daily oral administration of 400mg/kg body wt of F5 inhibited growth and progression of prostate tumor xenografts by ~75% in nude mice, as evidenced by tumor volume measurements and non-invasive real-time bioluminescence imaging. These data generate compelling grounds to further examine the chemopreventive efficacy of the most active fraction of SPGE and suggest its potential usefulness as a dietary supplement for prostate cancer management. PMID:23629419

  15. A Model for Cell Wall Dissolution in Mating Yeast Cells: Polarized Secretion and Restricted Diffusion of Cell Wall Remodeling Enzymes Induces Local Dissolution

    OpenAIRE

    Huberman, Lori B.; Murray, Andrew W.

    2014-01-01

    Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell...

  16. Reproducible analyses of microbial food for advanced life support systems

    Science.gov (United States)

    Petersen, Gene R.

    1988-01-01

    The use of yeasts in controlled ecological life support systems (CELSS) for microbial food regeneration in space required the accurate and reproducible analysis of intracellular carbohydrate and protein levels. The reproducible analysis of glycogen was a key element in estimating overall content of edibles in candidate yeast strains. Typical analytical methods for estimating glycogen in Saccharomyces were not found to be entirely aplicable to other candidate strains. Rigorous cell lysis coupled with acid/base fractionation followed by specific enzymatic glycogen analyses were required to obtain accurate results in two strains of Candida. A profile of edible fractions of these strains was then determined. The suitability of yeasts as food sources in CELSS food production processes is discussed.

  17. In Vitro Polarized Resonance Raman Study of N719 and N719-TBP in Dye Sensitized Solar Cells

    DEFF Research Database (Denmark)

    Hassing, Søren; Jernshøj, Kit Drescher; Lund, Torben;

    2016-01-01

    experimental results on N719/TiO2 – DSCs that by combining an analysis of the wave number dependent polarization of these modes with the small shifts observed in the visible absorption spectra of adsorbed, non-adsorbed molecules and degradation products new and more reliable information about dye stability and...... about the adsorption of the dye on TiO2 can be obtained. Furthermore it is found that the polarization fluorescence anisotropy is very different for adsorbed and non-adsorbed dye molecules. This information is automatically obtained when processing the Raman data. The conclusion is that if the...... TiO2substrate applied FTIR,un-polarized Raman (RS) and un-polarized resonance Raman (RRS) spectroscopy. In the un-polarized RRS studies of N719/TiO2 – DSCs the discussion of the adsorption of N719 was based on the rather weak carbonyl or carboxyl group stretching vibrations and on minor spectral...

  18. Endostatin inhibits the growth and migration of 4T1 mouse breast cancer cells by skewing macrophage polarity toward the M1 phenotype.

    Science.gov (United States)

    Guo, Hua; Liu, Yanan; Gu, Junlian; Wang, Yue; Liu, Lianqin; Zhang, Ping; Li, Yang

    2016-06-01

    The phenotypic diversity of tumor-associated macrophages (TAMs) increases with tumor development. One of the hallmarks of malignancy is the polarization of TAMs from a pro-immune (M1) phenotype to an immunosuppressive (M2) phenotype. However, the molecular basis of this process is still unclear. Endostatin is a powerful inhibitor of angiogenesis capable of suppressing tumor growth and metastasis. Here, we demonstrate that endostatin induces RAW264.7 cell polarization toward the M1 phenotype in vitro. Endostatin has no effect on TAM numbers in vivo, but results in an increased proportion of F4/80(+)Nos2(+) cells and a decreased proportion of F4/80(+)CD206(+) cells. Overexpression of endostatin in RAW264.7 cells resulted in a decrease in the phosphorylation of STAT3, an increase in expression of vascular endothelial growth factor A and placental growth factor, and an increase in the phosphorylation of STAT1, IκBα and p65 proteins compared with controls. These results indicate that endostatin regulates macrophage polarization, promoting the M1 phenotype by targeting NF-κB and STAT signaling. PMID:27034233

  19. Polarized synchrotron emission from the equatorial current sheet in gamma-ray pulsars

    CERN Document Server

    Cerutti, Benoît; Philippov, Alexander A

    2016-01-01

    Polarization is a powerful diagnostic tool to constrain the site of the high-energy pulsed emission and particle acceleration in gamma-ray pulsars. Recent particle-in-cell simulations of pulsar magnetosphere suggest that high-energy emission results from particles accelerated in the equatorial current sheet emitting synchrotron radiation. In this study, we re-examine the simulation data to compute the phase-resolved polarization properties. We find that the emission is mildly polarized and that there is an anticorrelation between the flux and the degree of linear polarization (on-pulse: ~15%, off-pulse: ~30%). The decrease of polarization during pulses is mainly attributed to the formation of caustics in the current sheet. Each pulse of light is systematically accompanied by a rapid swing of the polarization angle due to the change of the magnetic polarity when the line of sight passes through the current sheet. The optical polarization pattern observed in the Crab can be well-reproduced for a pulsar inclinat...

  20. Developmental regulation of planar cell polarity and hair-bundle morphogenesis in auditory hair cells: lessons from human and mouse genetics.

    Science.gov (United States)

    Lu, Xiaowei; Sipe, Conor W

    2016-01-01

    Hearing loss is the most common and costly sensory defect in humans and genetic causes underlie a significant proportion of affected individuals. In mammals, sound is detected by hair cells (HCs) housed in the cochlea of the inner ear, whose function depends on a highly specialized mechanotransduction organelle, the hair bundle. Understanding the factors that regulate the development and functional maturation of the hair bundle is crucial for understanding the pathophysiology of human deafness. Genetic analysis of deafness genes in animal models, together with complementary forward genetic screens and conditional knock-out mutations in essential genes, have provided great insights into the molecular machinery underpinning hair-bundle development and function. In this review, we highlight recent advances in our understanding of hair-bundle morphogenesis, with an emphasis on the molecular pathways governing hair-bundle polarity and orientation. We next discuss the proteins and structural elements important for hair-cell mechanotransduction as well as hair-bundle cohesion and maintenance. In addition, developmental signals thought to regulate tonotopic features of HCs are introduced. Finally, novel approaches that complement classic genetics for studying the molecular etiology of human deafness are presented. WIREs Dev Biol 2016, 5:85-101. doi: 10.1002/wdev.202 For further resources related to this article, please visit the WIREs website. PMID:26265594

  1. Reproducibility of scoring emphysema by HRCT

    International Nuclear Information System (INIS)

    Purpose: We evaluated the reproducibility of three visual scoring methods of emphysema and compared these methods with pulmonary function tests (VC, DLCO, FEV1 and FEV%) among farmer's lung patients and farmers. Material and Methods: Three radiologists examined high-resolution CT images of farmer's lung patients and their matched controls (n=70) for chronic interstitial lung diseases. Intraobserver reproducibility and interobserver variability were assessed for three methods: severity, Sanders' (extent) and Sakai. Pulmonary function tests as spirometry and diffusing capacity were measured. Results: Intraobserver -values for all three methods were good (0.51-0.74). Interobserver varied from 0.35 to 0.72. The Sanders' and the severity methods correlated strongly with pulmonary function tests, especially DLCO and FEV1. Conclusion: The Sanders' method proved to be reliable in evaluating emphysema, in terms of good consistency of interpretation and good correlation with pulmonary function tests

  2. Reproducibility of scoring emphysema by HRCT

    Energy Technology Data Exchange (ETDEWEB)

    Malinen, A.; Partanen, K.; Rytkoenen, H.; Vanninen, R. [Kuopio Univ. Hospital (Finland). Dept. of Clinical Radiology; Erkinjuntti-Pekkanen, R. [Kuopio Univ. Hospital (Finland). Dept. of Pulmonary Diseases

    2002-04-01

    Purpose: We evaluated the reproducibility of three visual scoring methods of emphysema and compared these methods with pulmonary function tests (VC, DLCO, FEV1 and FEV%) among farmer's lung patients and farmers. Material and Methods: Three radiologists examined high-resolution CT images of farmer's lung patients and their matched controls (n=70) for chronic interstitial lung diseases. Intraobserver reproducibility and interobserver variability were assessed for three methods: severity, Sanders' (extent) and Sakai. Pulmonary function tests as spirometry and diffusing capacity were measured. Results: Intraobserver -values for all three methods were good (0.51-0.74). Interobserver varied from 0.35 to 0.72. The Sanders' and the severity methods correlated strongly with pulmonary function tests, especially DLCO and FEV1. Conclusion: The Sanders' method proved to be reliable in evaluating emphysema, in terms of good consistency of interpretation and good correlation with pulmonary function tests.

  3. Is My Network Module Preserved and Reproducible?

    OpenAIRE

    Peter Langfelder; Rui Luo; Oldham, Michael C.; Steve Horvath

    2011-01-01

    In many applications, one is interested in determining which of the properties of a network module change across conditions. For example, to validate the existence of a module, it is desirable to show that it is reproducible (or preserved) in an independent test network. Here we study several types of network preservation statistics that do not require a module assignment in the test network. We distinguish network preservation statistics by the type of the underlying network. Some preservati...

  4. Reproducing color images using custom inks

    OpenAIRE

    Stollnitz, Eric J.; Ostromoukhov, Victor; Salesin, David H.

    1998-01-01

    We investigate the general problem of reproducing color images on an offset press using custom inks in any combination and number. While this problem has been explored previously for the case of two inks, there are a number of new mathematical and algorithmic challenges that arise as the number of inks increases. These challenges include more complex gamut mapping strategies, more efficient ink selection strategies, and fast and numerically accurate methods for computing ink separations in si...

  5. Sustainability and Reproducibility via Containerized Computing

    OpenAIRE

    Nagler, Robert; Bruhwiler, David; Moeller, Paul; Webb, Stephen

    2015-01-01

    Recent developments in the commercial open source community have catalysed the use of Linux containers for scalable deployment of web-based applications to the cloud. Scientific software can be containerized with dependencies, configuration files, post-processing tools and even simulation results, referred to as containerized computing. This new approach promises to significantly improve sustainability, productivity and reproducibility. We present our experiences, technology, and future plans...

  6. A Reproducible Research Framework for Audio Inpainting

    OpenAIRE

    Adler, Amir; Emiya, Valentin; Jafari, Maria,; Elad, Michael; Gribonval, Rémi; Plumbley, Mark D.

    2011-01-01

    International audience We introduce a unified framework for the restoration of distorted audio data, leveraging the Image Inpainting concept and covering existing audio applications. In this framework, termed Audio Inpainting, the distorted data is considered missing and its location is assumed to be known. We further introduce baseline approaches based on sparse representations. For this new audio inpainting concept, we provide reproducible-research tools including: the handling of audio ...

  7. MPI Benchmarking Revisited: Experimental Design and Reproducibility

    OpenAIRE

    Hunold, Sascha; Carpen-Amarie, Alexandra

    2015-01-01

    The Message Passing Interface (MPI) is the prevalent programming model used on today's supercomputers. Therefore, MPI library developers are looking for the best possible performance (shortest run-time) of individual MPI functions across many different supercomputer architectures. Several MPI benchmark suites have been developed to assess the performance of MPI implementations. Unfortunately, the outcome of these benchmarks is often neither reproducible nor statistically sound. To overcome th...

  8. Effects of polarization and p-type GaN resistivity on the spectral response of InGaN/GaN multiple quantum well solar cells

    International Nuclear Information System (INIS)

    Effects of polarization and p-type GaN resistivity on the spectral response of InGaN/GaN multiple quantum well (MQW) solar cells are investigated. It is found that due to the reduction of piezoelectric polarization and the enhancement of tunneling transport of photo-generated carriers in MQWs, the external quantum efficiency (EQE) of the solar cells increases in a low energy spectral range (λ > 370 nm) when the barrier thickness value decreases from 15 nm to 7.5 nm. But the EQE decreases abruptly when the barrier thickness value decreases down to 3.75 nm. The reasons for these experimental results are analyzed. We are aware that the reduction of depletion width in MQW region, caused by the high resistivity of the p-type GaN layer may be the main reason for the abnormally low EQE value at long wavelengths (λ > 370 nm)

  9. A Framework for Reproducible Latent Fingerprint Enhancements.

    Science.gov (United States)

    Carasso, Alfred S

    2014-01-01

    Photoshop processing of latent fingerprints is the preferred methodology among law enforcement forensic experts, but that appproach is not fully reproducible and may lead to questionable enhancements. Alternative, independent, fully reproducible enhancements, using IDL Histogram Equalization and IDL Adaptive Histogram Equalization, can produce better-defined ridge structures, along with considerable background information. Applying a systematic slow motion smoothing procedure to such IDL enhancements, based on the rapid FFT solution of a Lévy stable fractional diffusion equation, can attenuate background detail while preserving ridge information. The resulting smoothed latent print enhancements are comparable to, but distinct from, forensic Photoshop images suitable for input into automated fingerprint identification systems, (AFIS). In addition, this progressive smoothing procedure can be reexamined by displaying the suite of progressively smoother IDL images. That suite can be stored, providing an audit trail that allows monitoring for possible loss of useful information, in transit to the user-selected optimal image. Such independent and fully reproducible enhancements provide a valuable frame of reference that may be helpful in informing, complementing, and possibly validating the forensic Photoshop methodology. PMID:26601028

  10. Polarization and relaxation of radon

    CERN Document Server

    Tardiff, E R; Chupp, T E; Gulyuz, K; Lefferts, R S; Lorenzon, W; Nuss-Warren, S R; Pearson, M R; Pietralla, N; Rainovski, G; Sell, J F; Sprouse, G D

    2006-01-01

    Investigations of the polarization and relaxation of $^{209}$Rn by spin exchange with laser optically pumped rubidium are reported. On the order of one million atoms per shot were collected in coated and uncoated glass cells. Gamma-ray anisotropies were measured as a signal of the alignment (second order moment of the polarization) resulting from the combination of polarization and quadrupole relaxation at the cell walls. The temperature dependence over the range 130$^\\circ$C to 220$^\\circ$C shows the anisotropies increasing with increasing temperature as the ratio of the spin exchange polarization rate to the wall relaxation rate increases faster than the rubidium polarization decreases. Polarization relaxation rates for coated and uncoated cells are presented. In addition, improved limits on the multipole mixing ratios of some of the main gamma-ray transitions have been extracted. These results are promising for electric dipole moment measurements of octupole-deformed $^{223}$Rn and other isotopes, provided...

  11. Activation of JNK signaling links IgI mutations to disruption of the cell polarity and epithelial organization in Drosophila imaginal discs

    Institute of Scientific and Technical Information of China (English)

    Ming-wei Zhu; Tian-chi Xin; Shun-yan Weng; Yin Gao; Ying-jie Zhang; Qi Li; Ming-fa Li

    2010-01-01

    Dear Editor, Identification of Drosophila melanogaster as a model organism for cancer research has facilitated the exploration of human tumor malignancy. In Drosophila, lossof-function mutations in the neoplastic tumor suppressor genes (nTSGs) lethal(2)giant larvae (lgl), discs large (dlg) or scribble (scrib) cause a malignant tumor-like phenotype characteristic of disrupted cell polarity and overgrowth in epithelial tissues such as imaginal discs [1].

  12. Intracellular Trafficking of Bile Salt Export Pump (ABCB11) in Polarized Hepatic Cells: Constitutive Cycling between the Canalicular Membrane and rab11-positive EndosomesV⃞

    OpenAIRE

    Wakabayashi, Yoshiyuki; Lippincott-Schwartz, Jennifer; Arias, Irwin M.

    2004-01-01

    The bile salt export pump (BSEP, ABCB11) couples ATP hydrolysis with transport of bile acids into the bile canaliculus of hepatocytes. Its localization in the apical canalicular membrane is physiologically regulated by the demand to secrete biliary components. To gain insight into how such localization is regulated, we studied the intracellular trafficking of BSEP tagged with yellow fluorescent protein (YFP) in polarized WIF-B9 cells. Confocal imaging revealed that BSEP-YFP was localized at t...

  13. Copy number variation analysis implicates the cell polarity gene glypican 5 as a human spina bifida candidate gene.

    Science.gov (United States)

    Bassuk, Alexander G; Muthuswamy, Lakshmi B; Boland, Riley; Smith, Tiffany L; Hulstrand, Alissa M; Northrup, Hope; Hakeman, Matthew; Dierdorff, Jason M; Yung, Christina K; Long, Abby; Brouillette, Rachel B; Au, Kit Sing; Gurnett, Christina; Houston, Douglas W; Cornell, Robert A; Manak, J Robert

    2013-03-15

    Neural tube defects (NTDs) are common birth defects of complex etiology. Family and population-based studies have confirmed a genetic component to NTDs. However, despite more than three decades of research, the genes involved in human NTDs remain largely unknown. We tested the hypothesis that rare copy number variants (CNVs), especially de novo germline CNVs, are a significant risk factor for NTDs. We used array-based comparative genomic hybridization (aCGH) to identify rare CNVs in 128 Caucasian and 61 Hispanic patients with non-syndromic lumbar-sacral myelomeningocele. We also performed aCGH analysis on the parents of affected individuals with rare CNVs where parental DNA was available (42 sets). Among the eight de novo CNVs that we identified, three generated copy number changes of entire genes. One large heterozygous deletion removed 27 genes, including PAX3, a known spina bifida-associated gene. A second CNV altered genes (PGPD8, ZC3H6) for which little is known regarding function or expression. A third heterozygous deletion removed GPC5 and part of GPC6, genes encoding glypicans. Glypicans are proteoglycans that modulate the activity of morphogens such as Sonic Hedgehog (SHH) and bone morphogenetic proteins (BMPs), both of which have been implicated in NTDs. Additionally, glypicans function in the planar cell polarity (PCP) pathway, and several PCP genes have been associated with NTDs. Here, we show that GPC5 orthologs are expressed in the neural tube, and that inhibiting their expression in frog and fish embryos results in NTDs. These results implicate GPC5 as a gene required for normal neural tube development. PMID:23223018

  14. The Wnt Frizzled Receptor MOM-5 Regulates the UNC-5 Netrin Receptor through Small GTPase-Dependent Signaling to Determine the Polarity of Migrating Cells.

    Directory of Open Access Journals (Sweden)

    Naomi Levy-Strumpf

    2015-08-01

    Full Text Available Wnt and Netrin signaling regulate diverse essential functions. Using a genetic approach combined with temporal gene expression analysis, we found a regulatory link between the Wnt receptor MOM-5/Frizzled and the UNC-6/Netrin receptor UNC-5. These two receptors play key roles in guiding cell and axon migrations, including the migration of the C. elegans Distal Tip Cells (DTCs. DTCs migrate post-embryonically in three sequential phases: in the first phase along the Antero-Posterior (A/P axis, in the second, along the Dorso-Ventral (D/V axis, and in the third, along the A/P axis. Loss of MOM-5/Frizzled function causes third phase A/P polarity reversals of the migrating DTCs. We show that an over-expression of UNC-5 causes similar DTC A/P polarity reversals and that unc-5 deficits markedly suppress the A/P polarity reversals caused by mutations in mom-5/frizzled. This implicates MOM-5/Frizzled as a negative regulator of unc-5. We provide further evidence that small GTPases mediate MOM-5's regulation of unc-5 such that one outcome of impaired function of small GTPases like CED-10/Rac and MIG-2/RhoG is an increase in unc-5 function. The work presented here demonstrates the existence of cross talk between components of the Netrin and Wnt signaling pathways and provides further insights into the way guidance signaling mechanisms are integrated to orchestrate directed cell migration.

  15. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication and...... characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  16. Rapid paracellular transmigration of Campylobacter jejuni across polarized epithelial cells without affecting TER: role of proteolytic-active HtrA cleaving E-cadherin but not fibronectin

    Directory of Open Access Journals (Sweden)

    Boehm Manja

    2012-04-01

    Full Text Available Abstract Background Campylobacter jejuni is one of the most important bacterial pathogens causing food-borne illness worldwide. Crossing the intestinal epithelial barrier and host cell entry by C. jejuni is considered the primary reason of damage to the intestinal tissue, but the molecular mechanisms as well as major bacterial and host cell factors involved in this process are still widely unclear. Results In the present study, we characterized the serine protease HtrA (high-temperature requirement A of C. jejuni as a secreted virulence factor with important proteolytic functions. Infection studies and in vitro cleavage assays showed that C. jejuni’s HtrA triggers shedding of the extracellular E-cadherin NTF domain (90 kDa of non-polarised INT-407 and polarized MKN-28 epithelial cells, but fibronectin was not cleaved as seen for H. pylori’s HtrA. Deletion of the htrA gene in C. jejuni or expression of a protease-deficient S197A point mutant did not lead to loss of flagella or reduced bacterial motility, but led to severe defects in E-cadherin cleavage and transmigration of the bacteria across polarized MKN-28 cell layers. Unlike other highly invasive pathogens, transmigration across polarized cells by wild-type C. jejuni is highly efficient and is achieved within a few minutes of infection. Interestingly, E-cadherin cleavage by C. jejuni occurs in a limited fashion and transmigration required the intact flagella as well as HtrA protease activity, but does not reduce transepithelial electrical resistance (TER as seen with Salmonella, Shigella, Listeria or Neisseria. Conclusion These results suggest that HtrA-mediated E-cadherin cleavage is involved in rapid crossing of the epithelial barrier by C. jejuni via a very specific mechanism using the paracellular route to reach basolateral surfaces, but does not cleave the fibronectin receptor which is necessary for cell entry.

  17. Rapid paracellular transmigration of Campylobacter jejuni across polarized epithelial cells without affecting TER: role of proteolytic-active HtrA cleaving E-cadherin but not fibronectin

    LENUS (Irish Health Repository)

    Boehm, Manja

    2012-04-25

    AbstractBackgroundCampylobacter jejuni is one of the most important bacterial pathogens causing food-borne illness worldwide. Crossing the intestinal epithelial barrier and host cell entry by C. jejuni is considered the primary reason of damage to the intestinal tissue, but the molecular mechanisms as well as major bacterial and host cell factors involved in this process are still widely unclear.ResultsIn the present study, we characterized the serine protease HtrA (high-temperature requirement A) of C. jejuni as a secreted virulence factor with important proteolytic functions. Infection studies and in vitro cleavage assays showed that C. jejuni’s HtrA triggers shedding of the extracellular E-cadherin NTF domain (90 kDa) of non-polarised INT-407 and polarized MKN-28 epithelial cells, but fibronectin was not cleaved as seen for H. pylori’s HtrA. Deletion of the htrA gene in C. jejuni or expression of a protease-deficient S197A point mutant did not lead to loss of flagella or reduced bacterial motility, but led to severe defects in E-cadherin cleavage and transmigration of the bacteria across polarized MKN-28 cell layers. Unlike other highly invasive pathogens, transmigration across polarized cells by wild-type C. jejuni is highly efficient and is achieved within a few minutes of infection. Interestingly, E-cadherin cleavage by C. jejuni occurs in a limited fashion and transmigration required the intact flagella as well as HtrA protease activity, but does not reduce transepithelial electrical resistance (TER) as seen with Salmonella, Shigella, Listeria or Neisseria.ConclusionThese results suggest that HtrA-mediated E-cadherin cleavage is involved in rapid crossing of the epithelial barrier by C. jejuni via a very specific mechanism using the paracellular route to reach basolateral surfaces, but does not cleave the fibronectin receptor which is necessary for cell entry.

  18. Towards reproducible, scalable lateral molecular electronic devices

    Science.gov (United States)

    Durkan, Colm; Zhang, Qian

    2014-08-01

    An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress. The resulting nanogap devices are used to measure the electrical properties of small numbers of two different molecular species with different end-groups, namely 1,4-butane dithiol and 1,5-diamino-2-methylpentane. Fluctuations in the current reveal that in the case of the dithiol molecule devices, individual molecules conduct intermittently, with the fluctuations becoming more pronounced at larger biases.

  19. Towards reproducible, scalable lateral molecular electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Durkan, Colm, E-mail: cd229@eng.cam.ac.uk; Zhang, Qian [Nanoscience Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2014-08-25

    An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress. The resulting nanogap devices are used to measure the electrical properties of small numbers of two different molecular species with different end-groups, namely 1,4-butane dithiol and 1,5-diamino-2-methylpentane. Fluctuations in the current reveal that in the case of the dithiol molecule devices, individual molecules conduct intermittently, with the fluctuations becoming more pronounced at larger biases.

  20. Dynamic electrical behavior of halide perovskite based solar cells

    OpenAIRE

    Nemnes, George Alexandru; Besleaga, Cristina; Tomulescu, Andrei Gabriel; Pintilie, Ioana; Pintilie, Lucian; Torfason, Kristinn; Manolescu, Andrei

    2016-01-01

    A dynamic electrical model is introduced to investigate the hysteretic effects in the I-V characteristics of perovskite based solar cells. By making a simple ansatz for the polarization relaxation, our model is able to reproduce qualitatively and quantitatively detailed features of measured I-V characteristics. Pre-poling effects are discussed, pointing out the differences between initially over- and under-polarized samples. In particular, the presence of the current over-shoot observed in th...

  1. Polarized electroproduction

    International Nuclear Information System (INIS)

    A new type of information on proton structure, its internal spin structure, has recently become available from a new type of experiment, polarized electroproduction. The scattering of longitudinally polarized electrons was measured by longitudinally polarized protons. The quantity measured was the asymmetry A, the normalized difference between the differential scattering cross sections for the antiparallel and parallel spin configurations. Data have been obtained for elastic, deep inelastic, and reasonance region scattering. Polarized electrons were obtained by the photoionization of polarized Li atomic beam with pulsed UV light. The important characteristics of the polarized electron beam are the intensity of 109 e-/1.5 μs pulse at repetition rate of 120 pps, and polarization of 0.85 +- 0.08. A number of data on deep inelastic scattering, preliminary asymmetry in the resonance region and others are described and illustrated in several graphs. There are several implications in these data; 1) test of Bjorken sum rule, 2) scaling, and 3) models of proton structure, which are mentioned hereinafter. The Bjorken sum rule predicts equality in the scaling limit between an integral over ω of the product of spin-averaged nucleon structure function W2 and spin dependent function A, and the ratio of axial vector to vector weak coupling constants of beta decay. Data on the asymmetries in deep inelastic and resonance region scattering will make possible the evaluation of a famous old problem -- the effect of proton polarizability on the hyperfine structure interval in hydrogen. (Wakatsuki, Y.)

  2. Heart rate variability reproducibility during exercise

    International Nuclear Information System (INIS)

    The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined. (paper)

  3. Estimating the optimal number of membrane electrode assembly catalyst layers for proton exchange membrane fuel cell by considering open circuit voltage and polarization

    International Nuclear Information System (INIS)

    This paper reports on a thin polymer membrane with a self-humidifying membrane electrode assembly (MEA) using water generated from the cathode. However, the open circuit voltage was low because the activation and diffusion polarizations were high. Therefore, a multilayered MEA was prepared for a proton exchange membrane fuel cell by the screen-printing method to reduce the two polarizations and improve the open circuit voltage and power density. The MEA consists of a Nafion 115 membrane and a Vulcan XC-72 commercial catalyst (20 wt.% Pt/C) on the anode and cathode. The performances of the multilayered MEA were evaluated for the current-voltage (I-V) characteristics of single cells. In addition, the activation and diffusion polarizations and the open circuit voltage were analyzed for a prepared sample. Excellent characteristics were obtained for the MEA multilayered structure (anode: two layers; cathode: three layers). The activity of both electrodes was increased and a high power density was obtained compared to single-layered MEA.

  4. A chemo-mechanical free-energy-based approach to model durotaxis and extracellular stiffness-dependent contraction and polarization of cells.

    Science.gov (United States)

    Shenoy, Vivek B; Wang, Hailong; Wang, Xiao

    2016-02-01

    We propose a chemo-mechanical model based on stress-dependent recruitment of myosin motors to describe how the contractility, polarization and strain in cells vary with the stiffness of their surroundings and their shape. A contractility tensor, which depends on the distribution of myosin motors, is introduced to describe the chemical free energy of the cell due to myosin recruitment. We explicitly include the contributions to the free energy that arise from mechanosensitive signalling pathways (such as the SFX, Rho-Rock and MLCK pathways) through chemo-mechanical coupling parameters. Taking the variations of the total free energy, which consists of the chemical and mechanical components, in accordance with the second law of thermodynamics provides equations for the temporal evolution of the active stress and the contractility tensor. Following this approach, we are able to recover the well-known Hill relation for active stresses, based on the fundamental principles of irreversible thermodynamics rather than phenomenology. We have numerically implemented our free energy-based approach to model spatial distribution of strain and contractility in (i) cells supported by flexible microposts, (ii) cells on two-dimensional substrates, and (iii) cells in three-dimensional matrices. We demonstrate how the polarization of the cells and the orientation of stress fibres can be deduced from the eigenvalues and eigenvectors of the contractility tensor. Our calculations suggest that the chemical free energy of the cell decreases with the stiffness of the extracellular environment as the cytoskeleton polarizes in response to stress-dependent recruitment of molecular motors. The mechanical energy, which includes the strain energy and motor potential energy, however, increases with stiffness, but the overall energy is lower for cells in stiffer environments. This provides a thermodynamic basis for durotaxis, whereby cells preferentially migrate towards stiffer regions of the

  5. High spin polarization at the HERA electron storage ring

    International Nuclear Information System (INIS)

    This paper describes the progress made in 1992 towards increasing the vertical electron beam polarization at HERA. Utilizing harmonic spin-orbit corrections and beam tuning, the vertical polarization has been increased from 15% to nearly 60% at a beam energy of 26.7 GeV. The long-term reproducibility of the polarization is excellent. Measurements of the build-up time and the energy dependence of the polarization are also described. (orig.)

  6. Reproducibility of UAV-based photogrammetric surface models

    Science.gov (United States)

    Anders, Niels; Smith, Mike; Cammeraat, Erik; Keesstra, Saskia

    2016-04-01

    Soil erosion, rapid geomorphological change and vegetation degradation are major threats to the human and natural environment in many regions. Unmanned Aerial Vehicles (UAVs) and Structure-from-Motion (SfM) photogrammetry are invaluable tools for the collection of highly detailed aerial imagery and subsequent low cost production of 3D landscapes for an assessment of landscape change. Despite the widespread use of UAVs for image acquisition in monitoring applications, the reproducibility of UAV data products has not been explored in detail. This paper investigates this reproducibility by comparing the surface models and orthophotos derived from different UAV flights that vary in flight direction and altitude. The study area is located near Lorca, Murcia, SE Spain, which is a semi-arid medium-relief locale. The area is comprised of terraced agricultural fields that have been abandoned for about 40 years and have suffered subsequent damage through piping and gully erosion. In this work we focused upon variation in cell size, vertical and horizontal accuracy, and horizontal positioning of recognizable landscape features. The results suggest that flight altitude has a significant impact on reconstructed point density and related cell size, whilst flight direction affects the spatial distribution of vertical accuracy. The horizontal positioning of landscape features is relatively consistent between the different flights. We conclude that UAV data products are suitable for monitoring campaigns for land cover purposes or geomorphological mapping, but special care is required when used for monitoring changes in elevation.

  7. Polarity protein Crumbs homolog-3 (CRB3) regulates ectoplasmic specialization dynamics through its action on F-actin organization in Sertoli cells

    Science.gov (United States)

    Gao, Ying; Lui, Wing-yee; Lee, Will M.; Cheng, C. Yan

    2016-01-01

    Crumbs homolog 3 (or Crumbs3, CRB3) is a polarity protein expressed by Sertoli and germ cells at the basal compartment in the seminiferous epithelium. CRB3 also expressed at the blood-testis barrier (BTB), co-localized with F-actin, TJ proteins occludin/ZO-1 and basal ES (ectoplasmic specialization) proteins N-cadherin/β-catenin at stages IV-VII only. The binding partners of CRB3 in the testis were the branched actin polymerization protein Arp3, and the barbed end-capping and bundling protein Eps8, illustrating its possible role in actin organization. CRB3 knockdown (KD) by RNAi in Sertoli cells with an established tight junction (TJ)-permeability barrier perturbed the TJ-barrier via changes in the distribution of TJ- and basal ES-proteins at the cell-cell interface. These changes were the result of CRB3 KD-induced re-organization of actin microfilaments, in which actin microfilaments were truncated, and extensively branched, thereby destabilizing F-actin-based adhesion protein complexes at the BTB. Using Polyplus in vivo-jetPEI as a transfection medium with high efficiency for CRB3 KD in the testis, the CRB3 KD testes displayed defects in spermatid and phagosome transport, and also spermatid polarity due to a disruption of F-actin organization. In summary, CRB3 is an actin microfilament regulator, playing a pivotal role in organizing actin filament bundles at the ES. PMID:27358069

  8. The predominant WT1 isoform (+KTS) encodes a DNA-binding protein targeting the planar cell polarity gene Scribble in renal podocytes.

    Science.gov (United States)

    Wells, Julie; Rivera, Miguel N; Kim, Woo Jae; Starbuck, Kristen; Haber, Daniel A

    2010-07-01

    WT1 encodes a tumor suppressor first identified by its inactivation in Wilms' Tumor. Although one WT1 splicing variant encodes a well-characterized zinc finger transcription factor, little is known about the function of the most prevalent WT1 isoform, whose DNA binding domain is disrupted by a three-amino acid (KTS) insertion. Using cells that conditionally express WT1(+KTS), we undertook a genome-wide chromatin immunoprecipitation and cloning analysis to identify candidate WT1(+KTS)-regulated promoters. We identified the planar cell polarity gene Scribble (SCRB) as the first WT1(+KTS) target gene in podocytes of the kidney. WT1 and SCRB expression patterns overlap precisely in developing renal glomeruli of mice, and WT1(+KTS) binds to a 33-nucleotide region within the Scribble promoter in mouse and human cell lines and kidneys. Together, our results support a role for the predominant WT1(+KTS) isoform in transcriptional regulation and suggest a link between the WT1-dependent tumor suppressor pathway and a key component of the planar cell polarity pathway. PMID:20571064

  9. The predominant WT1 isoform (+KTS) encodes a DNA binding protein targeting the planar cell polarity gene Scribble in renal podocytes

    Science.gov (United States)

    Wells, Julie; Rivera, Miguel N.; Kim, Woo Jae; Starbuck, Kristen; Haber, Daniel A.

    2010-01-01

    WT1 encodes a tumor suppressor, first identified by its inactivation in Wilms Tumor. While one WT1 splicing variant encodes a well-characterized zinc finger transcription factor, little is known about the function of the most prevalent WT1 isoform, whose DNA binding domain is disrupted by a three amino acid (KTS) insertion. Using cells which conditionally express WT1(+KTS), we undertook a genome-wide chromatin immunoprecipitation and cloning (ChIP-cloning) analysis to identify candidate WT1(+KTS) regulated promoters. We identified the planar cell polarity (PCP) gene Scribble (SCRB) as the first WT1(+KTS) target gene in podocytes of the kidney. WT1 and SCRB expression patterns overlap precisely in developing renal glomeruli of mice, and WT1(+KTS) binds to a 33 nucleotide region within the Scribble promoter in both mouse and human cell lines and kidneys. Together, our results support a role for the predominant WT1(+KTS) isoform in transcriptional regulation and suggest a link between the WT1-dependent tumor suppressor pathway and a key component of the planar cell polarity pathway. PMID:20571064

  10. Human RPE Stem Cells Grown into Polarized RPE Monolayers on a Polyester Matrix Are Maintained after Grafting into Rabbit Subretinal Space

    Directory of Open Access Journals (Sweden)

    Boris V. Stanzel

    2014-01-01

    Full Text Available Transplantation of the retinal pigment epithelium (RPE is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC and induced pluripotent stem cell (iPSC-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies.

  11. The Wilms tumor gene, Wt1, is critical for mouse spermatogenesis via regulation of sertoli cell polarity and is associated with non-obstructive azoospermia in humans.

    Directory of Open Access Journals (Sweden)

    Xiao Na Wang

    Full Text Available Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA, indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1(flox and Cre-ER(TM mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood-testis barrier (BTB was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin and Wnt signaling genes (Wnt4, Wnt11 were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.

  12. High Reproducibility of ELISPOT Counts from Nine Different Laboratories

    DEFF Research Database (Denmark)

    Sundararaman, Srividya; Karulin, Alexey Y; Ansari, Tameem;

    2015-01-01

    The primary goal of immune monitoring with ELISPOT is to measure the number of T cells, specific for any antigen, accurately and reproducibly between different laboratories. In ELISPOT assays, antigen-specific T cells secrete cytokines, forming spots of different sizes on a membrane with variable...... laboratories. We plated PBMC at four different concentrations, 24 replicates each, in an IFN-γ ELISPOT assay with HCMV pp65 antigen. The ELISPOT plate, and an image file of the plate was counted in nine different laboratories using ImmunoSpot® Analyzers by (A) Basic Count™ relying on subjective counting...... parameters set by the respective investigators and (B) SmartCount™, an automated counting protocol by the ImmunoSpot® Software that uses statistics-based spot size auto-gating with spot intensity auto-thresholding. The average coefficient of variation (CV) for the mean values between independent laboratories...

  13. Systematic Methodology for Reproducible Optimizing Batch Operation

    DEFF Research Database (Denmark)

    Bonné, Dennis; Jørgensen, Sten Bay

    This contribution presents a systematic methodology for rapid acquirement of discrete-time state space model representations of batch processes based on their historical operation data. These state space models are parsimoniously parameterized as a set of local, interdependent models. The present...... contribution furthermore presents how the asymptotic convergence of Iterative Learning Control is combined with the closed-loop performance of Model Predictive Control to form a robust and asymptotically stable optimal controller for ensuring reliable and reproducible operation of batch processes. This...... controller may also be used for Optimizing control. The modeling and control performance is demonstrated on a fed-batch protein cultivation example. The presented methodologies lend themselves directly for application as Process Analytical Technologies (PAT)....

  14. Polar Lipid Extraction

    OpenAIRE

    sprotocols

    2014-01-01

    Author: Biotechniques Polar lipids are generally extracted from dry cell material using chloroform:methanol:0.3% NaCl (1:2:0.8 v/v/v). This may be carried out by adding 9.5 ml of this mixture to 100 mg of freeze dried cells, or by adding a suitable amount of chloroform, methanol and 0.3% NaCl to the cell material, or to the aqueous methanolic phase remaining from the lipoquinone extraction. 1. The aqueous methanolic phase (4 ml total volume), together with the cell material from the ...

  15. Activation and polar sequestration of PopA, a c-di-GMP effector protein involved in Caulobacter crescentus cell cycle control

    DEFF Research Database (Denmark)

    Ozaki, Shogo; Schalch-Moser, Annina; Zumthor, Ludwig; Manfredi, Pablo; Ebbensgaard, Anna Elisabeth; Schirmer, Tilman; Jenal, Urs

    2014-01-01

    When Caulobacter crescentus enters S-phase the replication initiation inhibitor CtrA dynamically positions to the old cell pole to be degraded by the polar ClpXP protease. Polar delivery of CtrA requires PopA and the diguanylate cyclase PleD that positions to the same pole. Here we present evidence...... that PopA originated through gene duplication from its paralogue response regulator PleD and subsequent co-option as c-di-GMP effector protein. While the C-terminal catalytic domain (GGDEF) of PleD is activated by phosphorylation of the N-terminal receiver domain, functional adaptation has reversed...... PopA to the cell pole in response to c-di-GMP binding. In agreement with the divergent activation and targeting mechanisms, distinct markers sequester PleD and PopA to the old cell pole upon S-phase entry. Together these data indicate that PopA adopted a novel role as topology specificity factor to...

  16. CANU workshop on polarization physics at COSY

    International Nuclear Information System (INIS)

    These proceedings contain the projection foils of the talks held at the named workshop. These concern general polarization physics, the polarization program at Saturne, the polarized beam at COSY, internal polarized targets, storage cell targets, a polarized 3He target, polarized proton and deuteron targets at ELSA, a polarimeter in the intermediate energy range, symmetry breaking in the NN interaction, the study of parity violation in the COSY energy range, the structure of simple and complex hadrons, intermediate-energy nuclear spectroscopy, polarization in proton reactions in the range from 130 to 500 MeV, polarized NN bremsstrahlung, polarization studies of dibaryonic resonances by means of pp↔πd, and spin-isospin excitations by means of polarized deuterons and 6Li. (HSI)

  17. The RHIC polarized H⁻ ion source.

    Science.gov (United States)

    Zelenski, A; Atoian, G; Raparia, D; Ritter, J; Steski, D

    2016-02-01

    A novel polarization technique had been successfully implemented for the Relativistic Heavy Ion Collider (RHIC) polarized H(-) ion source upgrade to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from external source) in the He-gaseous ionizer cell. Further proton polarization is produced in the process of polarized electron capture from the optically pumped Rb vapor. The use of high-brightness primary beam and large cross sections of charge-exchange cross sections resulted in production of high intensity H(-) ion beam of 85% polarization. The source very reliably delivered polarized beam in the RHIC Run-2013 and Run-2015. High beam current, brightness, and polarization resulted in 75% polarization at 23 GeV out of Alternating Gradient Synchrotron (AGS) and 60%-65% beam polarization at 100-250 GeV colliding beams in RHIC. PMID:26932068

  18. The RHIC polarized H- ion source

    Science.gov (United States)

    Zelenski, A.; Atoian, G.; Raparia, D.; Ritter, J.; Steski, D.

    2016-02-01

    A novel polarization technique had been successfully implemented for the Relativistic Heavy Ion Collider (RHIC) polarized H- ion source upgrade to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from external source) in the He-gaseous ionizer cell. Further proton polarization is produced in the process of polarized electron capture from the optically pumped Rb vapor. The use of high-brightness primary beam and large cross sections of charge-exchange cross sections resulted in production of high intensity H- ion beam of 85% polarization. The source very reliably delivered polarized beam in the RHIC Run-2013 and Run-2015. High beam current, brightness, and polarization resulted in 75% polarization at 23 GeV out of Alternating Gradient Synchrotron (AGS) and 60%-65% beam polarization at 100-250 GeV colliding beams in RHIC.

  19. Massive quark polarization in Quantum Chromodynamics subprocesses

    International Nuclear Information System (INIS)

    It is well known that the single polarization asymmetries are large in hyperon production in contrast with naive Quantum Chromodynamics predictions. We have explored the possibility of polarization of quarks in QCD subprocesses, assuming that the quark mass can be significant at energies of interest. The fourth order contribution to the single spin asymmetry in each important subprocess for strange quark production is calculated. Mass dependence and the kinematical properties of the polarization of the strange quark in the partons' center-of-mass frame are discussed. The s-quark polarization in the hadrons' center-of-mass frame is obtained by performing the convolution integrations with the initial state parton distribution functions. A fit to the hyperon polarization is presented that reproduces the unique and striking kinematic dependence of the data. This is evidence that the ''seed'' of the polarization is in the basic scattering process and it is dominated by the gluon fusion subprocess. 31 figs

  20. Polarization Energies at Organic-Organic Interfaces: Impact on the Charge Separation Barrier at Donor-Acceptor Interfaces in Organic Solar Cells.

    Science.gov (United States)

    Ryno, Sean M; Fu, Yao-Tsung; Risko, Chad; Brédas, Jean-Luc

    2016-06-22

    We probe the energetic landscape at a model pentacene/fullerene (C60) interface to investigate the interactions between positive and negative charges, which are critical to the processes of charge separation and recombination in organic solar cells. Using a polarizable force field, we find that polarization energy, i.e., the stabilization a charge feels due to its environment, is larger at the interface than in the bulk for both a positive and a negative charge. The combination of the charge being more stabilized at the interface and the Coulomb attraction between the charges results in a barrier to charge separation at the pentacene/C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations. However, the impact of molecular motions, i.e., the dynamics, at the interface at room temperature results in a distribution of polarization energies and in charge separation barriers that can be significantly reduced. The dynamic nature of the interface is thus critical, with the polarization energy distributions indicating that sites along the interface shift in time between favorable and unfavorable configurations for charge separation. PMID:27244215

  1. Polarization Energies at Organic–Organic Interfaces: Impact on the Charge Separation Barrier at Donor–Acceptor Interfaces in Organic Solar Cells

    KAUST Repository

    Ryno, Sean

    2016-05-31

    We probe the energetic landscape at a model pentacene/fullerene-C60 interface to investigate the interactions between positive and negative charges, which are critical to the processes of charge separation and recombination in organic solar cells. Using a polarizable force field, we find that polarization energy, i.e. the stabilization a charge feels due to its environment, is larger at the interface than in the bulk for both a positive and a negative charge. The combination of the charge being more stabilized at the interface and the Coulomb attraction between the charges, results in a barrier to charge separation at the pentacene-C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations. However, the impact of molecular motions, i.e., the dynamics, at the interface at room temperature results in a distribution of polarization energies and in charge separation barriers that can be significantly reduced. The dynamic nature of the interface is thus critical, with the polarization energy distributions indicating that sites along the interface shift in time between favorable and unfavorable configurations for charge separation.

  2. Empirical Bayes for group (DCM studies: a reproducibility study

    Directory of Open Access Journals (Sweden)

    Vladimir eLitvak

    2015-12-01

    Full Text Available This technical note addresses some key reproducibility issues in the dynamic causal modelling of group studies of event related potentials. Specifically, we address the reproducibility of Bayesian model comparison (and inferences about model parameters from three important perspectives: namely, (i reproducibility with independent data (obtained by averaging over odd and even trials. (ii Reproducibility over formally distinct models (namely, classic ERP and canonical microcircuit or CMC models and (iii reproducibility over inversion schemes (inversion of the grand average and estimation of group effects using empirical Bayes. Our hope was to illustrate the degree of reproducibility one can expect from DCM when analysing different data, under different models with different analyses.

  3. Empirical Bayes for Group (DCM) Studies: A Reproducibility Study.

    Science.gov (United States)

    Litvak, Vladimir; Garrido, Marta; Zeidman, Peter; Friston, Karl

    2015-01-01

    This technical note addresses some key reproducibility issues in the dynamic causal modelling of group studies of event related potentials. Specifically, we address the reproducibility of Bayesian model comparison (and inferences about model parameters) from three important perspectives namely: (i) reproducibility with independent data (obtained by averaging over odd and even trials); (ii) reproducibility over formally distinct models (namely, classic ERP and canonical microcircuit or CMC models); and (iii) reproducibility over inversion schemes (inversion of the grand average and estimation of group effects using empirical Bayes). Our hope was to illustrate the degree of reproducibility one can expect from DCM when analysing different data, under different models with different analyses. PMID:26733846

  4. Modulation of Rat Chorda Tympani NaCl Responses and Intracellular Na+ Activity in Polarized Taste Receptor Cells by pH

    OpenAIRE

    Lyall, Vijay; Alam, Rammy I.; Phan, Tam-Hao T.; Russell, Oneal F.; Malik, Shahbaz A.; Heck, Gerard L.; DeSimone, John A.

    2002-01-01

    Mixture interactions between sour and salt taste modalities were investigated in rats by direct measurement of intracellular pH (pHi) and Na+ activity ([Na+]i) in polarized fungiform taste receptor cells (TRCs) and by chorda tympani (CT) nerve recordings. Stimulating the lingual surface with NaCl solutions adjusted to pHs ranging between 2.0 and 10.3 increased the magnitude of NaCl CT responses linearly with increasing external pH (pHo). At pH 7.0, the epithelial sodium channel (ENaC) blocker...

  5. Mapping microscopic order in plant and mammalian cells and tissues: novel differential polarization attachment for new generation confocal microscopes (DP-LSM)

    International Nuclear Information System (INIS)

    Elucidation of the molecular architecture of complex, highly organized molecular macro-assemblies is an important, basic task for biology. Differential polarization (DP) measurements, such as linear (LD) and circular dichroism (CD) or the anisotropy of the fluorescence emission (r), which can be carried out in a dichrograph or spectrofluorimeter, respectively, carry unique, spatially averaged information about the molecular organization of the sample. For inhomogeneous samples—e.g. cells and tissues—measurements on macroscopic scale are not satisfactory, and in some cases not feasible, thus microscopic techniques must be applied. The microscopic DP-imaging technique, when based on confocal laser scanning microscope (LSM), allows the pixel by pixel mapping of anisotropy of a sample in 2D and 3D. The first DP-LSM configuration, which, in fluorescence mode, allowed confocal imaging of different DP quantities in real-time, without interfering with the ‘conventional’ imaging, was built on a Zeiss LSM410. It was demonstrated to be capable of determining non-confocally the linear birefringence (LB) or LD of a sample and, confocally, its FDLD (fluorescence detected LD), the degree of polarization (P) and the anisotropy of the fluorescence emission (r), following polarized and non-polarized excitation, respectively (Steinbach et al 2009 Acta Histochem.111 316–25). This DP-LSM configuration, however, cannot simply be adopted to new generation microscopes with considerably more compact structures. As shown here, for an Olympus FV500, we designed an easy-to-install DP attachment to determine LB, LD, FDLD and r, in new-generation confocal microscopes, which, in principle, can be complemented with a P-imaging unit, but specifically to the brand and type of LSM. (paper)

  6. The reproducible radio outbursts of SS Cygni

    CERN Document Server

    Russell, T D; Sivakoff, G R; Altamirano, D; O'Brien, T J; Page, K L; Templeton, M R; Koerding, E G; Knigge, C; Rupen, M P; Fender, R P; Heinz, S; Maitra, D; Markoff, S; Migliari, S; Remillard, R A; Russell, D M; Sarazin, C L; Waagen, E O

    2016-01-01

    We present the results of our intensive radio observing campaign of the dwarf nova SS Cyg during its 2010 April outburst. We argue that the observed radio emission was produced by synchrotron emission from a transient radio jet. Comparing the radio light curves from previous and subsequent outbursts of this system (including high-resolution observations from outbursts in 2011 and 2012) shows that the typical long and short outbursts of this system exhibit reproducible radio outbursts that do not vary significantly between outbursts, which is consistent with the similarity of the observed optical, ultraviolet and X-ray light curves. Contemporaneous optical and X-ray observations show that the radio emission appears to have been triggered at the same time as the initial X-ray flare, which occurs as disk material first reaches the boundary layer. This raises the possibility that the boundary region may be involved in jet production in accreting white dwarf systems. Our high spatial resolution monitoring shows th...

  7. Prion pathogenesis is faithfully reproduced in cerebellar organotypic slice cultures.

    Directory of Open Access Journals (Sweden)

    Jeppe Falsig

    Full Text Available Prions cause neurodegeneration in vivo, yet prion-infected cultured cells do not show cytotoxicity. This has hampered mechanistic studies of prion-induced neurodegeneration. Here we report that prion-infected cultured organotypic cerebellar slices (COCS experienced progressive spongiform neurodegeneration closely reproducing prion disease, with three different prion strains giving rise to three distinct patterns of prion protein deposition. Neurodegeneration did not occur when PrP was genetically removed from neurons, and a comprehensive pharmacological screen indicated that neurodegeneration was abrogated by compounds known to antagonize prion replication. Prion infection of COCS and mice led to enhanced fodrin cleavage, suggesting the involvement of calpains or caspases in pathogenesis. Accordingly, neurotoxicity and fodrin cleavage were prevented by calpain inhibitors but not by caspase inhibitors, whereas prion replication proceeded unimpeded. Hence calpain inhibition can uncouple prion replication from its neurotoxic sequelae. These data validate COCS as a powerful model system that faithfully reproduces most morphological hallmarks of prion infections. The exquisite accessibility of COCS to pharmacological manipulations was instrumental in recognizing the role of calpains in neurotoxicity, and significantly extends the collection of tools necessary for rigorously dissecting prion pathogenesis.

  8. Helicobacter pylori-Induced Disruption of Monolayer Permeability and Proinflammatory Cytokine Secretion in Polarized Human Gastric Epithelial Cells

    OpenAIRE

    Fiorentino, Maria; Ding, Hua; Blanchard, Thomas G.; Czinn, Steven J.; Sztein, Marcelo B.; Fasano, Alessio

    2013-01-01

    Helicobacter pylori infection of the stomach is related to the development of diverse gastric pathologies. The ability of H. pylori to compromise epithelial junctional complexes and to induce proinflammatory cytokines is believed to contribute to pathogenesis. The purpose of this study was to use an in vitro human gastric epithelial model to investigate the ability of H. pylori to affect permeability and the extent and polarity of the host inflammatory response. NCI-N87 monolayers were cocult...

  9. Sds22, a PP1 phosphatase regulatory subunit, regulates epithelial cell polarity and shape [Sds22 in epithelial morphology

    OpenAIRE

    Sung Hsin-Ho; Fletcher Georgina; Hidalgo Cristina; Grusche Felix A; Sahai Erik; Thompson Barry J

    2009-01-01

    Abstract Background How epithelial cells adopt their particular polarised forms is poorly understood. In a screen for genes regulating epithelial morphology in Drosophila, we identified sds22, a conserved gene previously characterised in yeast. Results In the columnar epithelia of imaginal discs or follicle cells, mutation of sds22 causes contraction of cells along their apical-basal axis, resulting in a more cuboidal morphology. In addition, the mutant cells can also display altered cell pol...

  10. Polar Stratigraphy

    Science.gov (United States)

    1999-01-01

    These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

  11. Modulation of Decidual Macrophage Polarization by Macrophage Colony-Stimulating Factor Derived from First-Trimester Decidual Cells: Implication in Preeclampsia.

    Science.gov (United States)

    Li, Min; Piao, Longzhu; Chen, Chie-Pein; Wu, Xianqing; Yeh, Chang-Ching; Masch, Rachel; Chang, Chi-Chang; Huang, S Joseph

    2016-05-01

    During human pregnancy, immune tolerance of the fetal semiallograft occurs in the presence of abundant maternal leukocytes. At the implantation site, macrophages comprise approximately 20% of the leukocyte population and act as primary mediators of tissue remodeling. Decidual macrophages display a balance between anti-inflammatory and proinflammatory phenotypes. However, a shift to an M1 subtype is reported in preeclampsia. Granulocyte-macrophage colony-stimulating-factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) are major differentiating factors that mediate M1 and M2 polarization, respectively. Previously, we observed the following: i) the preeclamptic decidua contains an excess of both macrophages and GM-CSF, ii) the preeclampsia-associated proinflammatory cytokines, IL-1β and tumor necrosis factor-α, markedly enhance GM-CSF and M-CSF expression in cultured leukocyte-free first-trimester decidual cells (FTDCs), iii) FTDC-secreted GM-CSF polarizes macrophages toward an M1 subtype. The microenvironment is a key determinant of macrophage phenotype. Thus, we examined proinflammatory stimulation of FTDC-secreted M-CSF and its role in macrophage development. Immunofluorescence staining demonstrated elevated M-CSF-positive decidual cell numbers in preeclamptic decidua. In FTDCs, IL-1β and tumor necrosis factor-α signal through the NF-κB pathway to induce M-CSF production, which does the following: i) enhances differentiation of and elevates CD163 expression in macrophages, ii) increases macrophage phagocytic capacity, and iii) inhibits signal-regulatory protein α expression by macrophages. These findings suggest that FTDC-secreted M-CSF modulates the decidual immune balance by inducing M2 macrophage polarization and phagocytic capacity in response to proinflammatory stimuli. PMID:26970370

  12. Increased basolateral sorting of carcinoembryonic antigen in a polarized colon carcinoma cell line after cholesterol depletion-Implications for treatment of inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Robert Ehehalt; Markus Krautter; Martin Zorn; Richard Sparla; Joachim Fūllekrug; Hasan Kulaksiz; Wolfgang Stremmel

    2008-01-01

    AIM:To investigate a possible increase of basolateral expression of carcinoembryonic antigen(CEA)by interfering with the apical transport machinery,we studied the effect of cholesterol depletion on CEA sorting and secretion.METHODS:Cholesterol depletion was performed in polarized Caco-2 cells using Iovastatin and methyl-βcyclodextrin.RESULTS:We show that CEA is predominantly expressed and secreted at the apical surface.Reduction of the cholesterol level of the cell by 40%-50% with Iovastatin and methyl-β-cyclodextrin led to a significant change of the apical-to-basolateral transport ratio towards the basolateral membrane.CONCLUSION:As basolateral expression of CEA has been suggested to have anti-inflamatory properties,Cholesterol depletion of enterocytes might be a potential approach to influence the course of inflammatory bowel disease.

  13. Functional analysis of Peutz-Jeghers mutations reveals that the LKB1 C-terminal region exerts a crucial role in regulating both the AMPK pathway and the cell polarity.

    NARCIS (Netherlands)

    Forcet, C.; Etienne-Manneville, S.; Gaude, H.; Fournier, L.; Debilly, S.; Salmi, M.; Baas, A.; Olschwang, S.; Clevers, J.C.; Billaud, M.

    2005-01-01

    Germline mutations of the LKB1 gene are responsible for the cancer-prone Peutz-Jeghers syndrome (PJS). LKB1 encodes a serine-threonine kinase that acts as a regulator of cell cycle, metabolism and cell polarity. The majority of PJS missense mutations abolish LKB1 enzymatic activity and thereby impai

  14. Combined TLR2 and TLR4 ligation in the context of bacterial or helminth extracts in human monocyte derived dendritic cells: Molecular correlates for Th1/Th2 polarization

    NARCIS (Netherlands)

    E. van Riet (Elly); B. Everts (Bart); K. Retra (Kim); M. Phylipsen (Marion); J.J. van Hellemond (Jaap); A.G.M. Tielens (Aloysius); D. van der Kleij (Desiree); F.C. Hartgers (Franca); M. Yazdanbakhsh (Maria)

    2009-01-01

    textabstractBackground: Recognition of pathogens by dendritic cells (DCs) through interaction with pattern recognition receptors, including Toll like receptors (TLR), is crucial for the initiation of appropriate polarized T helper (Th) cell responses. Yet, the characteristics and differences in mole

  15. Taurine behaves as an osmolyte in Madin-Darby canine kidney cells. Protection by polarized, regulated transport of taurine.

    OpenAIRE

    Uchida, S.; Nakanishi, T; Kwon, H M; Preston, A S; Handler, J S

    1991-01-01

    Using a clonal growth assay, we demonstrated that taurine, a nonperturbing osmolyte accumulated in kidney medulla, brain, and some other tissues of hypertonic experimental animals can function as a nonperturbing osmolyte in Madin-Darby canine kidney (MDCK) cells. The taurine content of hypertonic MDCK cells is twice that of isotonic MDCK cells (isotonic 160 nmol/mg protein; hypertonic 320 nmol/mg protein). Therefore we studied taurine transport in MDCK cells grown on porous supports and then ...

  16. Efficient polarization converter for projection displays.

    Science.gov (United States)

    Yip, W C; Huang, H C; Kwok, H S

    1997-09-01

    In the waveguiding limit, a twisted nematic liquid crystal cell behaves as an achromatic polarization rotator. We propose and demonstrate the application of such a polarization rotator to convert unpolarized light into linearly polarized light with almost 100% efficiency. This polarization converter has a 2:1 aspect ratio, which is close to the 16:9 ratio for modern televisions. It can be used therefore in a projection display with polarization-dependent light valves such as a liquid crystal light valve. Both transmittive and reflective light valves can be used. The temperature dependence of the achromatic polarization rotator is also studied. PMID:18259503

  17. Precision and reproducibility in AMS radiocarbon measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Hotchkis, M.A.; Fink, D.; Hua, Q.; Jacobsen, G.E.; Lawson, E. M.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

  18. Exosome derived from epigallocatechin gallate treated breast cancer cells suppresses tumor growth by inhibiting tumor-associated macrophage infiltration and M2 polarization

    International Nuclear Information System (INIS)

    tumor cells, which can be transferred to TAM via exosomes and inhibits TAM infiltration and M2 polarization. We suggest a novel mechanism by which EGCG exerts anti-tumor activity via regulation of TAM in tumor microenvironment

  19. A new mesenchymal stem cell (MSC paradigm: polarization into a pro-inflammatory MSC1 or an Immunosuppressive MSC2 phenotype.

    Directory of Open Access Journals (Sweden)

    Ruth S Waterman

    Full Text Available BACKGROUND: Our laboratory and others reported that the stimulation of specific Toll-like receptors (TLRs affects the immune modulating responses of human multipotent mesenchymal stromal cells (hMSCs. Toll-like receptors recognize "danger" signals, and their activation leads to profound cellular and systemic responses that mobilize innate and adaptive host immune cells. The danger signals that trigger TLRs are released following most tissue pathologies. Since danger signals recruit immune cells to sites of injury, we reasoned that hMSCs might be recruited in a similar way. Indeed, we found that hMSCs express several TLRs (e.g., TLR3 and TLR4, and that their migration, invasion, and secretion of immune modulating factors is drastically affected by specific TLR-agonist engagement. In particular, we noted diverse consequences on the hMSCs following stimulation of TLR3 when compared to TLR4 by our low-level, short-term TLR-priming protocol. PRINCIPAL FINDINGS: Here we extend our studies on the effect on immune modulation by specific TLR-priming of hMSCs, and based on our findings, propose a new paradigm for hMSCs that takes its cue from the monocyte literature. Specifically, that hMSCs can be polarized by downstream TLR signaling into two homogenously acting phenotypes we classify here as MSC1 and MSC2. This concept came from our observations that TLR4-primed hMSCs, or MSC1, mostly elaborate pro-inflammatory mediators, while TLR3-primed hMSCs, or MSC2, express mostly immunosuppressive ones. Additionally, allogeneic co-cultures of TLR-primed MSCs with peripheral blood mononuclear cells (PBMCs predictably lead to suppressed T-lymphocyte activation following MSC2 co-culture, and permissive T-lymphocyte activation in co-culture with MSC1. SIGNIFICANCE: Our study provides an explanation to some of the conflicting reports on the net effect of TLR stimulation and its downstream consequences on the immune modulating properties of stem cells. We further

  20. Downhill exercise-induced changes in gene expression related with macrophage polarization and myogenic cells in the triceps long head of rats.

    Science.gov (United States)

    Minari, André Luis Araujo; Oyama, Lila Missae; Dos Santos, Ronaldo Vagner Thomatieli

    2015-02-01

    Macrophages are one of the most heterogenic immune cells involved in skeletal muscle regeneration. After skeletal muscle damage, M1 phenotypes exhibit pro-inflammatory reaction. In a later stage, they are converted to M2 phenotypes with anti-inflammatory properties. To study when gene expressions of macrophage polarization are changed after damage induced by downhill exercise to exhaustion is the objective of this paper. Before (CTRL) and 0 h (G0), 24 h (G24), 48 h (G48) and 72 h (G72) after 18 bouts of downhill exercise, the animals were euthanised, and the triceps were dissected. We measured gene expression of macrophages (CD68 and CD163), myogenic cells (MyoD and myogenin) and quantified cytokine secretion (interleukin (IL)-6, IL-10 and tumour necrosis factor alpha (TNF-α)). The CD68 expression was lower in G72 compared with G24 (P = 0.005) while CD163 was higher in G48 compared with G24 (P = 0.04). The MyoD expression was higher in G72 compared with G0 (P = 0.04). The myogenin expression was lower in G24 compared with CTRL (P = 0.01) and restored in G72 compared with G24 (P = 0.007). The TNF-α was significantly higher at all times after 24 h (all compared with CTRL, with P = 0.03). The CD68 and CD163 expressions behaved distinctly after exercise, which indicates macrophage polarization between 24 and 48 h. The distinct expression of myogenin, concomitantly with MyoD elevation in G72, indicates that myogenic cell differentiation and the significant change of TNF-α level show an important role of this cytokine in these processes. PMID:25249340

  1. Visualization of Polarized Membrane Type 1 Matrix Metalloproteinase Activity in Live Cells by Fluorescence Resonance Energy Transfer Imaging*S⃞

    OpenAIRE

    Ouyang, Mingxing; Lu, Shaoying; Li, Xiao-Yan; Xu, Jing; Seong, Jihye; Giepmans, Ben N. G.; Shyy, John Y.-J.; Weiss, Stephen J.; Wang, Yingxiao

    2008-01-01

    Membrane type 1 matrix metalloproteinase (MT1-MMP) plays a critical role in cancer cell biology by proteolytically remodeling the extracellular matrix. Utilizing fluorescence resonance energy transfer (FRET) imaging, we have developed a novel biosensor, with its sensing element anchoring at the extracellular surface of cell membrane, to visualize MT1-MMP activity dynamically in live cells with subcellular resolution. Epidermal growth factor (EGF) induced significant FR...

  2. Complement protein C1q directs macrophage polarization and limits inflammasome activity during the uptake of apoptotic cells

    OpenAIRE

    Benoit, Marie E; Clarke, Elizabeth V.; Morgado, Pedro; Fraser, Deborah A.; Tenner, Andrea J.

    2012-01-01

    Deficiency in C1q, the recognition component of the classical complement cascade and a pattern recognition receptor involved in apoptotic cell clearance, leads to lupus-like auto-immune diseases characterized by auto-antibodies to self proteins and aberrant innate immune cell activation likely due to impaired clearance of apoptotic cells. Here, we developed an autologous system using primary human lymphocytes and monocyte-derived macrophages (HMDMs) to characterize the effect of C1q on macrop...

  3. Complement protein C1q directs macrophage polarization and limits inflammasome activity during the uptake of apoptotic cells.

    OpenAIRE

    Benoit, Marie E; Clarke, Elizabeth V.; Morgado, Pedro; Fraser, Deborah A.; Tenner, Andrea J.

    2012-01-01

    Deficiency in C1q, the recognition component of the classical complement cascade and a pattern recognition receptor involved in apoptotic cell clearance, leads to lupus-like autoimmune diseases characterized by auto-antibodies to self proteins and aberrant innate immune cell activation likely due to impaired clearance of apoptotic cells. In this study, we developed an autologous system using primary human lymphocytes and human monocyte-derived macrophages (HMDMs) to characterize the effect of...

  4. Polarization of T Lymphocytes Is Regulated by Mesenchymal Stem Cells in NZBWF1 and BALB/c Mice

    Directory of Open Access Journals (Sweden)

    Yayi Hou

    2007-05-01

    Full Text Available Mesenchymal stem cells (MSCs have been shown to suppress proliferation andactivation of T lymphocytes in vivo and in vitro although the molecular mechanism of theimmunosuppressive effect is not completely understood. To investigate theimmunoregulatory effects of mice bone marrow mesenchymal stem cells on T lymphocyte,MSCs from NZBWF1 and BALB/c mice were isolated and expanded from bone marrow,and identified with cell morphology and the surface phenotypes. CD3+ T lymphocytesisolated by nylon wool columns were co-cultured with PMA with or without the two strainsof MSCs. Then T cell apoptosis and intercellular cytokines of T cell were assessed by flowcytometry. Quantification of transcription factors T-box (T-bet and GATA-binding protein3 (GATA-3 expressed in T cells was detected by RT-PCR and western blot. Our resultsshowed that there was a decrease of CD3+ T cell apoptosis when NW MSCs or Bc MSCswere added, and an increase of Th2 subset by NW MSCs and Th1 subset by Bc MSCs wereobserved by co-culturing MSCs with T lymphocytes. It is suggested that, by favoring Th1-cell development and inhibitory Th2-cell development, normal MSCs might interfere withthe SLE development, and that marrow-derived NW MSCs had defectiveimmunoregulatory function when compared with MSCs from healthy mouse strains.

  5. LFA-1/ICAM-1 Ligation in Human T Cells Promotes Th1 Polarization through a GSK3β Signaling-Dependent Notch Pathway.

    Science.gov (United States)

    Verma, Navin K; Fazil, M H U Turabe; Ong, Seow Theng; Chalasani, Madhavi Latha S; Low, Jian Hui; Kottaiswamy, Amuthavalli; P, Praseetha; Kizhakeyil, Atish; Kumar, Sunil; Panda, Aditya K; Freeley, Michael; Smith, Sinead M; Boehm, Bernhard O; Kelleher, Dermot

    2016-07-01

    In this study, we report that the integrin LFA-1 cross-linking with its ligand ICAM-1 in human PBMCs or CD4(+) T cells promotes Th1 polarization by upregulating IFN-γ secretion and T-bet expression. LFA-1 stimulation in PBMCs, CD4(+) T cells, or the T cell line HuT78 activates the Notch pathway by nuclear translocation of cleaved Notch1 intracellular domain (NICD) and upregulation of target molecules Hey1 and Hes1. Blocking LFA-1 by a neutralizing Ab or specific inhibition of Notch1 by a γ-secretase inhibitor substantially inhibits LFA-1/ICAM-1-mediated activation of Notch signaling. We further demonstrate that the Notch pathway activation is dependent on LFA-1/ICAM-1-induced inactivation of glycogen synthase kinase 3β (GSK3β), which is mediated via Akt and ERK. Furthermore, in silico analysis in combination with coimmunoprecipitation assays show an interaction between NICD and GSK3β. Thus, there exists a molecular cross-talk between LFA-1 and Notch1 through the Akt/ERK-GSK3β signaling axis that ultimately enhances T cell differentiation toward Th1. Although clinical use of LFA-1 antagonists is limited by toxicity related to immunosuppression, these findings support the concept that Notch inhibitors could be attractive for prevention or treatment of Th1-related immunologic disorders and have implications at the level of local inflammatory responses. PMID:27206767

  6. Par1b links lumen polarity with LGN-NuMA positioning for distinct epithelial cell division phenotypes

    NARCIS (Netherlands)

    Lazaro-Dieguez, Francisco; Cohen, David; Fernandez, Dawn; Hodgson, Louis; van IJzendoorn, Sven C. D.; Muesch, Anne

    2013-01-01

    Columnar epithelia establish their luminal domains and their mitotic spindles parallel to the basal surface and undergo symmetric cell divisions in which the cleavage furrow bisects the apical domain. Hepatocyte lumina interrupt the lateral domain of neighboring cells perpendicular to two basal doma

  7. A neural coding scheme reproducing foraging trajectories

    Science.gov (United States)

    Gutiérrez, Esther D.; Cabrera, Juan Luis

    2015-12-01

    The movement of many animals may follow Lévy patterns. The underlying generating neuronal dynamics of such a behavior is unknown. In this paper we show that a novel discovery of multifractality in winnerless competition (WLC) systems reveals a potential encoding mechanism that is translatable into two dimensional superdiffusive Lévy movements. The validity of our approach is tested on a conductance based neuronal model showing WLC and through the extraction of Lévy flights inducing fractals from recordings of rat hippocampus during open field foraging. Further insights are gained analyzing mice motor cortex neurons and non motor cell signals. The proposed mechanism provides a plausible explanation for the neuro-dynamical fundamentals of spatial searching patterns observed in animals (including humans) and illustrates an until now unknown way to encode information in neuronal temporal series.

  8. Polarized secretion of interleukin (IL-6 and IL-8 by human airway epithelia 16HBE14o- cells in response to cationic polypeptide challenge.

    Directory of Open Access Journals (Sweden)

    Alison Wai-ming Chow

    Full Text Available BACKGROUND: The airway epithelium participates in asthmatic inflammation in many ways. Target cells of the epithelium can respond to a variety of inflammatory mediators and cytokines. Damage to the surface epithelium occurs following the secretion of eosinophil-derived, highly toxic cationic proteins. Moreover, the surface epithelium itself is responsible for the synthesis and release of cytokines that cause the selective recruitment, retention, and accumulation of various inflammatory cells. To mimic the damage seen during asthmatic inflammation, the bronchial epithelium can be challenged with highly charged cationic polypeptides such as poly-L-arginine. METHODOLOGY/PRINCIPAL FINDINGS: In this study, human bronchial epithelial cells, 16HBE14o- cells, were "chemically injured" by exposing them to poly-l-arginine as a surrogate of the eosinophil cationic protein. Cytokine antibody array data showed that seven inflammatory mediators were elevated out of the 40 tested, including marked elevation in interleukin (IL-6 and IL-8 secretion. IL-6 and IL-8 mRNA expression levels were elevated as measured with real-time PCR. Cell culture supernatants from apical and basolateral compartments were collected, and the IL-6 and IL-8 production was quantified with ELISA. IL-6 and IL-8 secretion by 16HBE14o- epithelia into the apical compartment was significantly higher than that from the basolateral compartment. Using specific inhibitors, the production of IL-6 and IL-8 was found to be dependent on p38 MAPK, ERK1/2 MAPK, and NF-kappaB pathways. CONCLUSIONS/SIGNIFICANCE: The results clearly demonstrate that damage to the bronchial epithelia by poly-L-arginine stimulates polarized IL-6 and IL-8 secretion. This apically directed secretion of cytokines may play an important role in orchestrating epithelial cell responses to inflammation.

  9. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  10. The endocrine disruption properties of an adipose contaminant mixture extracted from East Greenland polar bears studied in the H295R cell line

    DEFF Research Database (Denmark)

    Hjorth, R.; Letcher, R. J.; Blair, D.;

    -MS/MS analysis showed that all 10 adipose extracts caused significant changes to the hormone levels in H295R compared to solvent controls. Levels of progestagens expressed upstream of the enzyme CYP17 (pregnenolone and progesterone) increased with a corresponding decrease in androgens expressed downstream...... in 2011. Specifically, the tissue extracts were tested for steroidogenic activity in the human adrenocortical carcinoma cell line H295R. These extracts contained a complex mixture of measured polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and brominated flame retardants (BFRs). GC...... (dehydroepiandrosterone and androstenedione). These results demonstrated comprehensive in vitro effects of POPs extracted from polar bear adipose tissue on key elements in the steroidogenesis, and identifies disruption of CYP17 activity as a mode of action. A POP-induced interference with CYP17 can potentially explain...

  11. Particle-in-cell simulation for parametric decays of a circularly polarized Alfvén wave in relativistic thermal electron-positron plasma

    Energy Technology Data Exchange (ETDEWEB)

    López, Rodrigo A., E-mail: rlopez186@gmail.com; Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Alejandro Valdivia, J. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Santiago (Chile)

    2014-03-15

    Parametric decays of a left-handed circularly polarized Alfvén wave propagating along a constant background magnetic field in a relativistic thermal electron-positron plasma are studied by means of a one dimensional relativistic particle-in-cell simulation. Relativistic effects are included in the Lorentz equation for the momentum of the particles and in their thermal motion, by considering a Maxwell-Jüttner velocity distribution function for the initial condition. In the linear stage of the simulation, we find many instabilities that match the predictions of relativistic fluid theory. In general, the growth rates of the instabilities increase as the pump wave amplitude is increased, and decrease with a raise in the plasma temperatures. We have confirmed that for very high temperatures the Alfvén branch is suppressed, consistent with analytical calculations.

  12. The R software environment in reproducible geoscientific research

    Science.gov (United States)

    Pebesma, Edzer; Nüst, Daniel; Bivand, Roger

    2012-04-01

    Reproducibility is an important aspect of scientific research, because the credibility of science is at stake when research is not reproducible. Like science, the development of good, reliable scientific software is a social process. A mature and growing community relies on the R software environment for carrying out geoscientific research. Here we describe why people use R and how it helps in communicating and reproducing research.

  13. Using prediction markets to estimate the reproducibility of scientific research

    OpenAIRE

    Dreber-Almenberg, Anna; Pfeiffer, Thomas; Almenberg, Johan; Isaksson, Siri; Wilson, Brad; Chen, Yiling; Nosek, Brian A.; Johannesson, Magnus

    2015-01-01

    Concerns about a lack of reproducibility of statistically significant results have recently been raised in many fields, and it has been argued that this lack comes at substantial economic costs. We here report the results from prediction markets set up to quantify the reproducibility of 44 studies published in prominent psychology journals and replicated in the Reproducibility Project: Psychology. The prediction markets predict the outcomes of the replications well and outperform a survey of ...

  14. The GTP-bound and Sumoylated Form of the rab17 Small Molecular Weight GTPase Selectively Binds Syntaxin 2 in Polarized Hepatic WIF-B Cells.

    Science.gov (United States)

    Striz, Anneliese C; Tuma, Pamela L

    2016-04-29

    A major focus for our laboratory is identifying the molecules and mechanisms that regulate polarized apical protein sorting in hepatocytes, the major epithelial cells of the liver. These trafficking pathways are regulated, in part, by small molecular weight rab GTPases. We chose to investigate rab17, whose expression is restricted to polarized epithelial cells, is enriched in liver, and has been implicated in regulating basolateral to apical transcytosis. To initiate our studies, we generated three recombinant adenoviruses expressing wild type, constitutively active (GTP bound), or dominant-negative (GDP bound) rab17. Immunoblotting revealed rab17 immunoreactive species at 25 kDa (the predicted rab17 molecular mass) and 40 kDa. We determined that mono-sumoylation of the 25-kDa rab17 is responsible for the shift in molecular mass, and that rab17 prenylation is required for sumoylation. We further determined that sumoylation selectively promotes interactions with syntaxin 2 (but not syntaxins 3 or 4) and that these interactions are nucleotide dependent. Furthermore, a K68R-mutated rab17 led to the redistribution of syntaxin 2 and 5' nucleotidase from the apical membrane to subapical puncta, whereas multidrug resistance protein 2 distributions were not changed. Together these data are consistent with the proposed role of rab17 in vesicle fusion with the apical plasma membrane and further implicate sumoylation as an important mediator of protein-protein interactions. The selectivity in syntaxin binding and apical protein redistribution further suggests that rab17 and syntaxin 2 mediate fusion of transcytotic vesicles at the apical surface. PMID:26957544

  15. A 3D-printed high power nuclear spin polarizer.

    Science.gov (United States)

    Nikolaou, Panayiotis; Coffey, Aaron M; Walkup, Laura L; Gust, Brogan M; LaPierre, Cristen D; Koehnemann, Edward; Barlow, Michael J; Rosen, Matthew S; Goodson, Boyd M; Chekmenev, Eduard Y

    2014-01-29

    Three-dimensional printing with high-temperature plastic is used to enable spin exchange optical pumping (SEOP) and hyperpolarization of xenon-129 gas. The use of 3D printed structures increases the simplicity of integration of the following key components with a variable temperature SEOP probe: (i) in situ NMR circuit operating at 84 kHz (Larmor frequencies of (129)Xe and (1)H nuclear spins), (ii) thermoelectric temperature control, (v) retroreflection optics, and (vi) optomechanical alignment system. The rapid prototyping endowed by 3D printing dramatically reduces production time and expenses while allowing reproducibility and integration of "off-the-shelf" components and enables the concept of printing on demand. The utility of this SEOP setup is demonstrated here to obtain near-unity (129)Xe polarization values in a 0.5 L optical pumping cell, including ∼74 ± 7% at 1000 Torr xenon partial pressure, a record value at such high Xe density. Values for the (129)Xe polarization exponential build-up rate [(3.63 ± 0.15) × 10(-2) min(-1)] and in-cell (129)Xe spin-lattice relaxation time (T1 = 2.19 ± 0.06 h) for 1000 Torr Xe were in excellent agreement with the ratio of the gas-phase polarizations for (129)Xe and Rb (PRb ∼ 96%). Hyperpolarization-enhanced (129)Xe gas imaging was demonstrated with a spherical phantom following automated gas transfer from the polarizer. Taken together, these results support the development of a wide range of chemical, biochemical, material science, and biomedical applications. PMID:24400919

  16. Uteroglobin, an apically secreted protein of the uterine epithelium, is secreted non-polarized form MDCK cells and mainly basolaterally from Caco-2 cells

    DEFF Research Database (Denmark)

    Vogel, L K; Suske, G; Beato, M;

    1993-01-01

    A complete cDNA encoding rabbit uteroglobin was constructed and expressed in MDCK and Caco-2 cells. The MDCK cells secrete uteroglobin in approximately equal amounts to the apical and the basolateral side, whereas the Caco-2 cells secrete uteroglobin mainly to the basolateral side. Both MDCK and ...... the endometrial epithelium has an apical default pathway or recognises a sorting signal not recognised by MDCK cells and Caco-2 cells. Our data thus show that a soluble molecule can be secreted at the apical, the basolateral or both membranes depending on the cell type....

  17. Combined 17β-Estradiol with TCDD Promotes M2 Polarization of Macrophages in the Endometriotic Milieu with Aid of the Interaction between Endometrial Stromal Cells and Macrophages.

    Directory of Open Access Journals (Sweden)

    Yun Wang

    Full Text Available The goal of this study is to elucidate the effects of 17β-estradiol and TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin on macrophage phenotypes in the endometriotic milieu. Co-culture of endometrial stromal cells (ESCs and U937 cells (macrophage cell line was performed to simulate the endometriotic milieu and to determine the effects of 17β-estradiol and/or TCDD on IL10, IL12 production and HLA-DR, CD86 expression by U937 macrophages. We found that combining 17β-estradiol with TCDD has a synergistic effect on inducing M2 activation when macrophages are co-cultured with ESCs. Moreover, the combination of 17β-estradiol and TCDD significantly enhanced STAT3 and P38 phosphorylation in macrophages. Differentiation of M2 macrophages induced by 17β-estradiol and TCDD were effectively abrogated by STAT3 and P38MAPK inhibitors, but not by ERK1/2 and JNK inhibitors. In conclusion, 17β-estradiol and TCDD in the ectopic milieu may lead to the development of endometriosis by inducing M2 polarization of macrophages through activation of the STAT3 and P38MAPK pathways.

  18. Heavy Quarkonium Production and Polarization

    Science.gov (United States)

    Kang, Zhong-Bo; Qiu, Jian-Wei; Sterman, George

    2012-03-01

    We present a perturbative QCD factorization formalism for the production of heavy quarkonia of large transverse momentum pT at collider energies, which includes both the leading-power (LP) and next-to-leading-power (NLP) contributions to the cross section in the mQ2/pT2 expansion for heavy quark mass mQ. We estimate fragmentation functions in the nonrelativistic QCD formalism and reproduce the bulk of the large enhancement found in explicit next-to-leading-order calculations in the color-singlet model. Heavy quarkonia produced from NLP channels prefer longitudinal polarization.

  19. Preventing and curing citrulline-induced autoimmune arthritis in a humanized mouse model using a Th2-polarizing iNKT cell agonist.

    Science.gov (United States)

    Walker, Kyle M; Rytelewski, Mateusz; Mazzuca, Delfina M; Meilleur, Shannon A; Mannik, Lisa A; Yue, David; Brintnell, William C; Welch, Ian; Cairns, Ewa; Haeryfar, S M Mansour

    2012-07-01

    Invariant natural killer T (iNKT) cells are innate lymphocytes with unique reactivity to glycolipid antigens bound to non-polymorphic CD1d molecules. They are capable of rapidly releasing pro- and/or anti-inflammatory cytokines and constitute attractive targets for immunotherapy of a wide range of diseases including autoimmune disorders. In this study, we have explored the beneficial effects of OCH, a Th2-polarizing glycolipid agonist of iNKT cells, in a humanized mouse model of rheumatoid arthritis (RA) in which citrullinated human proteins are targeted by autoaggressive immune responses in mice expressing an RA susceptibility human leukocyte antigen (HLA) DR4 molecule. We found for the first time that treatment with OCH both prevents and cures citrulline-induced autoimmune arthritis as evidenced by resolved ankle swelling and reversed histopathological changes associated with arthritis. Also importantly, OCH treatment blocked the arthritogenic capacity of citrullinated antigen-experienced splenocytes without compromising their global responsiveness or altering the proportion of splenic naturally occurring CD4(+)CD25(+)FoxP3(+) regulatory T cells. Interestingly, administering the Th1-promoting iNKT cell glycolipid ligand α-C-galactosylceramide into HLA-DR4 transgenic mice increased the incidence of arthritis in these animals and exacerbated their clinical symptoms, strongly suggesting a role for Th1 responses in the pathogenesis of citrulline-induced arthritis. Therefore, our findings indicate a role for Th1-mediated immunopathology in citrulline-induced arthritis and provide the first evidence that iNKT cell manipulation by Th2-skewing glycolipids may be of therapeutic value in this clinically relevant model, a finding that is potentially translatable to human RA. PMID:21912419

  20. Control of mammary epithelial differentiation: basement membrane induces tissue-specific gene expression in the absence of cell-cell interaction and morphological polarity

    OpenAIRE

    1991-01-01

    Functional differentiation in mammary epithelia requires specific hormones and local environmental signals. The latter are provided both by extracellular matrix and by communication with adjacent cells, their action being intricately connected in what appears to be a cascade of events leading to milk production. To distinguish between the influence of basement membrane and that of cell-cell contact in this process, we developed a novel suspension culture assay in which mammary epithelial cell...

  1. A reproducible brain tumour model established from human glioblastoma biopsies

    Directory of Open Access Journals (Sweden)

    Li Xingang

    2009-12-01

    Full Text Available Abstract Background Establishing clinically relevant animal models of glioblastoma multiforme (GBM remains a challenge, and many commonly used cell line-based models do not recapitulate the invasive growth patterns of patient GBMs. Previously, we have reported the formation of highly invasive tumour xenografts in nude rats from human GBMs. However, implementing tumour models based on primary tissue requires that these models can be sufficiently standardised with consistently high take rates. Methods In this work, we collected data on growth kinetics from a material of 29 biopsies xenografted in nude rats, and characterised this model with an emphasis on neuropathological and radiological features. Results The tumour take rate for xenografted GBM biopsies were 96% and remained close to 100% at subsequent passages in vivo, whereas only one of four lower grade tumours engrafted. Average time from transplantation to the onset of symptoms was 125 days ± 11.5 SEM. Histologically, the primary xenografts recapitulated the invasive features of the parent tumours while endothelial cell proliferations and necrosis were mostly absent. After 4-5 in vivo passages, the tumours became more vascular with necrotic areas, but also appeared more circumscribed. MRI typically revealed changes related to tumour growth, several months prior to the onset of symptoms. Conclusions In vivo passaging of patient GBM biopsies produced tumours representative of the patient tumours, with high take rates and a reproducible disease course. The model provides combinations of angiogenic and invasive phenotypes and represents a good alternative to in vitro propagated cell lines for dissecting mechanisms of brain tumour progression.

  2. Quantum Electrodynamics vacuum polarization solver

    CERN Document Server

    Carneiro, Pedro; Fonseca, Ricardo; Silva, Luís

    2016-01-01

    The self-consistent modeling of vacuum polarization due to virtual electron-positron fluctuations is of relevance for many near term experiments associated with high intensity radiation sources and represents a milestone in describing scenarios of extreme energy density. We present a generalized finite-difference time-domain solver that can incorporate the modifications to Maxwells equations due to virtual vacuum polarization. Our multidimensional solver reproduced in one dimensional configurations the results for which an analytic treatment is possible, yielding vacuum harmonic generation and birefringence. The solver has also been tested for two-dimensional scenarios where finite laser beam spot sizes must be taken into account. We employ this solver to explore different types of counter-propagating configurations that can be relevant for future planned experiments aiming to detect quantum vacuum dynamics at ultra-high electromagnetic field intensities.

  3. Effect of Model Type on the Accuracy of Polarization and Nephelometric Measurements of Red-Blood-Cell Volume

    Science.gov (United States)

    Kugeiko, M. M.; Smunev, D. A.

    2016-05-01

    The effect of using different mathematical models of a red blood cell on the accuracy of the measured average volume for a population of red blood cells was evaluated. The accuracy was estimated based on regression equations between the retrieved microphysical and measured optical properties. Models of a sphere, oblate spheroid, and biconcave discoid represented as a disc with rounded edges and concavities in the middle were analyzed. It was shown that the error of the regression equations when determining the average red-blood-cell volume using the biconcave discoid model was 1%; spheroid, ~8%; and sphere, ~21%. The error of the average volume due to the model is a few percent for the spheroid and ~20% for the sphere.

  4. Acute myeloid leukaemia-derived Langerhans-like cells enhance Th1 polarization upon TLR2 engagement.

    Science.gov (United States)

    Bock, Stephanie; Murgueitio, Manuela S; Wolber, Gerhard; Weindl, Günther

    2016-03-01

    Langerhans cells (LCs) represent a highly specialized subset of epidermal dendritic cells (DCs), yet not fully understood in their function of balancing skin immunity. Here, we investigated in vitro generated Langerhans-like cells obtained from the human acute myeloid leukaemia cell line MUTZ-3 (MUTZ-LCs) to study TLR- and cytokine-dependent activation of epidermal DCs. MUTZ-LCs revealed high TLR2 expression and responded robustly to TLR2 engagement, confirmed by increased CD83, CD86, PD-L1 and IDO expression, upregulated IL-6, IL-12p40 and IL-23p19 mRNA levels IL-8 release. TLR2 activation reduced CCR6 and elevated CCR7 mRNA expression and induced migration of MUTZ-LCs towards CCL21. Similar results were obtained by stimulation with pro-inflammatory cytokines TNF-α and IL-1β whereas ligands of TLR3 and TLR4 failed to induce a fully mature phenotype. Despite limited cytokine gene expression and production for TLR2-activated MUTZ-LCs, co-culture with naive CD4(+) T cells led to significantly increased IFN-γ and IL-22 levels indicating Th1 differentiation independent of IL-12. TLR2-mediated effects were blocked by the putative TLR2/1 antagonist CU-CPT22, however, no selectivity for either TLR2/1 or TLR2/6 was observed. Computer-aided docking studies confirmed non-selective binding of the TLR2 antagonist. Taken together, our results indicate a critical role for TLR2 signalling in MUTZ-LCs considering the leukemic origin of the generated Langerhans-like cells. PMID:26794428

  5. Alignment of cell division axes in directed epithelial cell migration

    International Nuclear Information System (INIS)

    Cell division is an essential dynamic event in tissue remodeling during wound healing, cancer and embryogenesis. In collective migration, tensile stresses affect cell shape and polarity, hence, the orientation of the cell division axis is expected to depend on cellular flow patterns. Here, we study the degree of orientation of cell division axes in migrating and resting epithelial cell sheets. We use microstructured channels to create a defined scenario of directed cell invasion and compare this situation to resting but proliferating cell monolayers. In experiments, we find a strong alignment of the axis due to directed flow while resting sheets show very weak global order, but local flow gradients still correlate strongly with the cell division axis. We compare experimental results with a previously published mesoscopic particle based simulation model. Most of the observed effects are reproduced by the simulations. (paper)

  6. Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell

    DEFF Research Database (Denmark)

    Hsu, M.T.L.; Hetet, G.; Peng, A.; Harb, C.C.; Bachor, H.-A.; Johnsson, M.T.; Hope, J.J.; Lam, P.K.; Dantan, Aurelien Romain; Cviklinski, J.; Bramati, A.; Pinard, M.

    2006-01-01

    show results of the characterization of PSR in isotopically enhanced rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapor overwhelms the observation of squeezing. We present a theory that contains...... atomic noise terms and show that a null result in squeezing is consistent with this theory....

  7. POLARIZED RELEASE OF LIPID MEDIATORS DERIVED FROM PHOSPHOLIPASE A2 ACTIVITY IN A HUMAN BRONCHIAL CELL LINE

    Science.gov (United States)

    The release of arachidonic acid (AA) and platelet activating factory (PAF) from airway epithelial cells may be an important mediating factor in lung physiological and inflammatory processes. The type of lung response may be determined by the directional release of AA and PAF. We ...

  8. A mesoscale model used in the Polar regions: modification and verification

    Institute of Scientific and Technical Information of China (English)

    Ma Yan; Chen Shang

    2006-01-01

    A polar version of mesoscale model, Polar MM5 is introduced in the paper. The modifications for the polar MM5 dynamics and physics compared with standard MM5 are described. Additionally, parallel simulations of the Polar MM5 and original MM5 reveal that the Polar MM5 reproduces better near-surface variables forecasts than the original MM5 over the North American Arctic regions. The well predicted near surface temperature and mixing ratio by the Polar MM5 confirm the modified physical parameterization schemes in the Polar MM5 are appropriate for the research region.

  9. Opa binding to cellular CD66 receptors mediates the transcellular traversal of Neisseria gonorrhoeae across polarized T84 epithelial cell monolayers.

    Science.gov (United States)

    Wang, J; Gray-Owen, S D; Knorre, A; Meyer, T F; Dehio, C

    1998-11-01

    We have analysed the capacity of the 11 phase-variable, opacity-associated (Opa) proteins encoded by Neisseria gonorrhoeae MS11 to mediate traversal across polarized monolayers of the human colonic carcinoma T84 cell line. Gonococci expressing either the heparan sulphate proteoglycan (HSPG) binding Opa protein (Opa50) or no Opa protein (Opa-) did not interact with the apical pole of T84 monolayers, whereas the 10 variant Opa proteins previously shown to bind CD66 receptors were found to mediate efficient gonococcal adherence and transepithelial traversal. Consistent with this, T84 cells were shown by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting to co-express CD66a (BGP), CD66c (NCA) and CD66e (CEA). The recruitment of CD66 receptors by Opa-expressing gonococci indicates their involvement in mediating adherence to the surface of T84 cells, and these bacterial interactions could be inhibited completely using polyclonal antibodies cross-reacting with all of the CD66 proteins co-expressed on T84 cells. Consistent results were obtained when Opa proteins were expressed in Escherichia coli, suggesting that the Opa-CD66 interaction is sufficient to mediate bacterial traversal. Transcytosis of Opa-expressing N. gonorrhoeae or E. coli did not disrupt the barrier function of infected monolayers, as indicated by a sustained transepithelial electrical resistance (TEER) throughout the course of infection, and confocal laser scanning and electron microscopy both suggest a transcellular rather than a paracellular route of traversal across the monolayers. Parallels between the results seen here and previous work done with organ cultures confirm that T84 monolayers provide a valid model for studying neisserial interactions with the mucosal surface, and suggest that CD66 receptors contribute to this process in vivo. PMID:9822830

  10. Ricin crosses polarized human intestinal cells and intestines of ricin-gavaged mice without evident damage and then disseminates to mouse kidneys.

    Directory of Open Access Journals (Sweden)

    Alyssa D Flora

    Full Text Available Ricin is a potent toxin found in the beans of Ricinus communis and is often lethal for animals and humans when aerosolized or injected and causes significant morbidity and occasional death when ingested. Ricin has been proposed as a bioweapon because of its lethal properties, environmental stability, and accessibility. In oral intoxication, the process by which the toxin transits across intestinal mucosa is not completely understood. To address this question, we assessed the impact of ricin on the gastrointestinal tract and organs of mice after dissemination of toxin from the gut. We first showed that ricin adhered in a specific pattern to human small bowel intestinal sections, the site within the mouse gut in which a variable degree of damage has been reported by others. We then monitored the movement of ricin across polarized human HCT-8 intestinal monolayers grown in transwell inserts and in HCT-8 cell organoids. We observed that, in both systems, ricin trafficked through the cells without apparent damage until 24 hours post intoxication. We delivered a lethal dose of purified fluorescently-labeled ricin to mice by oral gavage and followed transit of the toxin from the gastrointestinal tracts to the internal organs by in vivo imaging of whole animals over time and ex vivo imaging of organs at various time points. In addition, we harvested organs from unlabeled ricin-gavaged mice and assessed them for the presence of ricin and for histological damage. Finally, we compared serum chemistry values from buffer-treated versus ricin-intoxicated animals. We conclude that ricin transverses human intestinal cells and mouse intestinal cells in situ prior to any indication of enterocyte damage and that ricin rapidly reaches the kidneys of intoxicated mice. We also propose that mice intoxicated orally with ricin likely die from distributive shock.

  11. Experiments in order to reproduce cold fusion results

    International Nuclear Information System (INIS)

    Three experiments have been performed in order to try and reproduce the cold fusion experiments reported by FLEISCHMANN and PONS (D2O electrolysis) and by the Frascati Group (D2 absorption in Ti at liquid nitrogen temperature). In the two electrolysis experiments, a Pd cathode was used together with a Pt anode and a Pd (D2) reference electrode, in acid and basic media. The electrolysis cell was surrounded by four neutron counters filled with an organic scintillator (NE213). The electronics made it possible to discriminate neutrons from gamma rays. The global efficiency for neutron detection was 20%, and the detection threshold was equal to 1 neutron/s/4π. A germanium detector (efficiency 70%) and a NaI crystal were used to record gamma ray spectra. In one of the experiments, tritium was measured in the solution before and after electrolysis. None of the two experiments showed neutron, gamma, or tritium production above background. In the third experiment, deuterium was absorbed in titanium by cooling at liquid nitrogen temperature, and desorbed by warming up at room temperature; both neutron and gamma emissions were recorded during these operations. The results of this experiment were also negative

  12. Current density and polarization curves for radial flow field patterns applied to PEMFCs (Proton Exchange Membrane Fuel Cells)

    International Nuclear Information System (INIS)

    A numerical solution of the current density and velocity fields of a 3-D PEM radial configuration fuel cell is presented. The energy, momentum and electrochemical equations are solved using a computational fluid dynamics (CFD) code based on a finite volume scheme. There are three cases of principal interest for this radial model: four channels, eight channels and twelve channels placed in a symmetrical path over the flow field plate. The figures for the current-voltage curves for the three models proposed are presented, and the main factors that affect the behavior of each of the curves are discussed. Velocity contours are presented for the three different models, showing how the fuel cell behavior is affected by the velocity variations in the radial configuration. All these results are presented for the case of high relative humidity. The favorable results obtained for this unconventional geometry seems to indicate that this geometry could replace the conventional commercial geometries currently in use.

  13. Immune polarization by hookworms: taking cues from T helper type 2, type 2 innate lymphoid cells and alternatively activated macrophages.

    Science.gov (United States)

    Nair, Meera G; Herbert, De'Broski R

    2016-06-01

    Cellular and molecular investigation of parasitic helminth infections has greatly accelerated the understanding of type 2 immune responses. However, there remains considerable debate regarding the specific leucocytes that kill parasites and whether these mechanisms are distinct from those responsible for tissue repair. Herein, we chronicle discoveries over the past decade highlighting current paradigms in type 2 immunity with a particular emphasis upon how CD4(+) T helper type 2 cells, type 2 innate lymphoid cells and alternatively activated macrophages coordinately control helminth-induced parasitism. Primarily, this review will draw from studies of the murine nematode parasite Nippostrongylus brasiliensis, which bears important similarities to the human hookworms Ancylostoma duodenale and Necator americanus. Given that one or more hookworm species currently infect millions of individuals across the globe, we propose that vaccine and/or pharmaceutical-based cure strategies targeting these affected human populations should incorporate the conceptual advances outlined herein. PMID:26928141

  14. Galectin-7 modulates the length of the primary cilia and wound repair in polarized kidney epithelial cells

    OpenAIRE

    Rondanino, Christine; Poland, Paul A.; Kinlough, Carol L.; Li, Hui; Rbaibi, Youssef; Myerburg, Michael M.; Al-Bataineh, Mohammad M.; Kashlan, Ossama B.; Pastor-Soler, Nuria M.; Hallows, Kenneth R.; Weisz, Ora A.; Apodaca, Gerard; Hughey, Rebecca P.

    2011-01-01

    Galectins (Gal) are β-galactoside-binding proteins that function in epithelial development and homeostasis. An overlapping role for Gal-3 and Gal-7 in wound repair was reported in stratified epithelia. Although Gal-7 was thought absent in simple epithelia, it was reported in a proteomic analysis of cilia isolated from cultured human airway, and we recently identified Gal-7 transcripts in Madin-Darby canine kidney (MDCK) cells (Poland PA, Rondanino C, Kinlough CL, Heimburg-Molinaro J, Arthur C...

  15. High reproducibility of histological characterization by whole virtual slide quantification; an example using carotid plaque specimens.

    Directory of Open Access Journals (Sweden)

    Joyce E P Vrijenhoek

    Full Text Available Tissue biobanks are an important source for discovery and validation studies aiming for new proteins that are causally related with disease development. There is an increasing demand for accurate and reproducible histological characterization, especially for subsequent analysis and interpretation of data in association studies. We assessed reproducibility of one semiquantative and two quantitative methods for histological tissue characterization. We introduce a new automated method for whole digital slide quantification. Carotid atherosclerotic plaques were used to test reproducibility.50 atherosclerotic plaques that were obtained during carotid endarterectomy were analysed. For the semiquantitative analysis, 6 different plaque characteristics were scored in categories by two independent observers, and Cohen's κ was used to test intra- and interobserver reproducibility. The computer-aided method (assessed by two independent observers and automated method were tested on CD68 (for macrophages and α smooth muscle actin (for smooth muscle cells stainings. Agreement for these two methods (done on a continuous scale was assessed by intraclass correlation coefficients (ICCs.For the semiquantitative analysis, κ values ranged from 0.55 to 0.69 for interobserver variability, and were slightly higher for intraobserver reproducibility in both observers. The computer-aided method yielded intra- and interobserver ICCs between 0.6 and 0.9. The new automated method performed most optimal regarding reproducibility, with ICCs ranging from 0.92 to 0.97.The analysis of performance of three methods for histological slide characterization on carotid atherosclerotic plaques showed high precision and agreement in repeated measurements for the automated method for whole digital slide quantification. We suggest that this method can fulfill the need for reproducible histological quantification.

  16. The 2009 Pandemic H1N1 and Triple-Reassortant Swine H1N1 Influenza Viruses Replicate Efficiently but Elicit an Attenuated Inflammatory Response in Polarized Human Bronchial Epithelial Cells

    OpenAIRE

    Zeng, Hui; Pappas, Claudia; Katz, Jacqueline M.; Tumpey, Terrence M

    2010-01-01

    The pandemic H1N1 virus of 2009 (2009 H1N1) produced a spectrum of disease ranging from mild illness to severe illness and death. Respiratory symptoms were frequently associated with virus infection, with relatively high rate of gastrointestinal symptoms reported. To better understand 2009 H1N1 virus pathogenesis in humans, we studied virus and host responses following infection of two cell types: polarized bronchial and pharyngeal epithelial cells, which exhibit many features of the human ai...

  17. Ionic polarization-induced current-voltage hysteresis in CH3NH3PbX3 perovskite solar cells.

    Science.gov (United States)

    Meloni, Simone; Moehl, Thomas; Tress, Wolfgang; Franckevičius, Marius; Saliba, Michael; Lee, Yong Hui; Gao, Peng; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Graetzel, Michael

    2016-01-01

    CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current-voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined experimental and computational approach. Experimentally the activation energy for the hysteretic process is determined and compared with the computational results. First-principles simulations show that the timescale for MA(+) rotation excludes a MA-related ferroelectric effect as possible origin for the observed hysteresis. On the other hand, the computationally determined activation energies for halide ion (vacancy) migration are in excellent agreement with the experimentally determined values, suggesting that the migration of this species causes the observed hysteretic behaviour of these solar cells. PMID:26852685

  18. Ionic polarization-induced current–voltage hysteresis in CH3NH3PbX3 perovskite solar cells

    Science.gov (United States)

    Meloni, Simone; Moehl, Thomas; Tress, Wolfgang; Franckevičius, Marius; Saliba, Michael; Lee, Yong Hui; Gao, Peng; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Graetzel, Michael

    2016-01-01

    CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current–voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined experimental and computational approach. Experimentally the activation energy for the hysteretic process is determined and compared with the computational results. First-principles simulations show that the timescale for MA+ rotation excludes a MA-related ferroelectric effect as possible origin for the observed hysteresis. On the other hand, the computationally determined activation energies for halide ion (vacancy) migration are in excellent agreement with the experimentally determined values, suggesting that the migration of this species causes the observed hysteretic behaviour of these solar cells. PMID:26852685

  19. Polarization losses under dynamic load cycle using multiwall carbon nanotube supported Pt catalyst in PEM fuel cell

    Science.gov (United States)

    Irmawati, Yuyun; Indriyati, Chaldun, Elsy Rahimi; Devianto, Hary

    2016-02-01

    Durability is one of the most important issues that are still being a hindrance for commercialization of polymer electrolyte membrane fuel cell (PEMFC). In this study, the degradation of PEMFC using multiwall carbon nanotube supported Pt catalyst (Pt/CNT) was investigated under dynamic load cycle procedure. The degradation was characterized by current density-voltage curves, cross-sectional scanning electron microscopy (SEM) images, and Fourier transforms infrared spectroscopy (FTIR) spectra. The load-cycle procedure was carried out for 50 cycles, where one cycle consisted of three steps (OCV-load current-constant voltage). An analysis of cell overpotentials indicated that the predominant source of performance degradation was due to ohmic losses, especially significant increase in the area specific resistance (Ra). After 50 cycles, Ra was calculated three times higher than that before durability test, from 0.67 to 1.74 Ωcm2. Based on the results from SEM images and FTIR spectra, there was no evidence of membrane degradation or thinning. Noticeable degradation was only observed from the increase in the interface gap between membrane, catalyst layer, and gas diffusion layer.

  20. Reproducible and controllable induction voltage adder for scaled beam experiments.

    Science.gov (United States)

    Sakai, Yasuo; Nakajima, Mitsuo; Horioka, Kazuhiko

    2016-08-01

    A reproducible and controllable induction adder was developed using solid-state switching devices and Finemet cores for scaled beam compression experiments. A gate controlled MOSFET circuit was developed for the controllable voltage driver. The MOSFET circuit drove the induction adder at low magnetization levels of the cores which enabled us to form reproducible modulation voltages with jitter less than 0.3 ns. Preliminary beam compression experiments indicated that the induction adder can improve the reproducibility of modulation voltages and advance the beam physics experiments. PMID:27587112

  1. The chicken yolk sac IgY receptor, a mammalian mannose receptor family member, transcytoses IgY across polarized epithelial cells.

    Science.gov (United States)

    Tesar, Devin B; Cheung, Evelyn J; Bjorkman, Pamela J

    2008-04-01

    In mammals the transfer of passive immunity from mother to young is mediated by the MHC-related receptor FcRn, which transports maternal IgG across epithelial cell barriers. In birds, maternal IgY in egg yolk is transferred across the yolk sac to passively immunize chicks during gestation and early independent life. The chicken yolk sac IgY receptor (FcRY) is the ortholog of the mammalian phospholipase A2 receptor, a mannose receptor family member, rather than an FcRn or MHC homolog. FcRn and FcRY both exhibit ligand binding at the acidic pH of endosomes and ligand release at the slightly basic pH of blood. Here we show that FcRY expressed in polarized mammalian epithelial cells functioned in endocytosis, bidirectional transcytosis, and recycling of chicken FcY/IgY. Confocal immunofluorescence studies demonstrated that IgY binding and endocytosis occurred at acidic but not basic pH, mimicking pH-dependent uptake of IgG by FcRn. Colocalization studies showed FcRY-mediated internalization via clathrin-coated pits and transport involving early and recycling endosomes. Disruption of microtubules partially inhibited apical-to-basolateral and basolateral-to-apical transcytosis, but not recycling, suggesting the use of different trafficking machinery. Our results represent the first cell biological evidence of functional equivalence between FcRY and FcRn and provide an intriguing example of how evolution can give rise to systems in which similar biological requirements in different species are satisfied utilizing distinct protein folds. PMID:18256279

  2. Evidence for involvement of Wnt signalling in body polarities, cell proliferation, and the neuro-sensory system in an adult ctenophore.

    Directory of Open Access Journals (Sweden)

    Muriel Jager

    Full Text Available Signalling through the Wnt family of secreted proteins originated in a common metazoan ancestor and greatly influenced the evolution of animal body plans. In bilaterians, Wnt signalling plays multiple fundamental roles during embryonic development and in adult tissues, notably in axial patterning, neural development and stem cell regulation. Studies in various cnidarian species have particularly highlighted the evolutionarily conserved role of the Wnt/β-catenin pathway in specification and patterning of the primary embryonic axis. However in another key non-bilaterian phylum, Ctenophora, Wnts are not involved in early establishment of the body axis during embryogenesis. We analysed the expression in the adult of the ctenophore Pleurobrachia pileus of 11 orthologues of Wnt signalling genes including all ctenophore Wnt ligands and Fz receptors and several members of the intracellular β-catenin pathway machinery. All genes are strongly expressed around the mouth margin at the oral pole, evoking the Wnt oral centre of cnidarians. This observation is consistent with primary axis polarisation by the Wnts being a universal metazoan feature, secondarily lost in ctenophores during early development but retained in the adult. In addition, local expression of Wnt signalling genes was seen in various anatomical structures of the body including in the locomotory comb rows, where their complex deployment suggests control by the Wnts of local comb polarity. Other important contexts of Wnt involvement which probably evolved before the ctenophore/cnidarian/bilaterian split include proliferating stem cells and progenitors irrespective of cell types, and developing as well as differentiated neuro-sensory structures.

  3. Evidence for involvement of Wnt signalling in body polarities, cell proliferation, and the neuro-sensory system in an adult ctenophore.

    Science.gov (United States)

    Jager, Muriel; Dayraud, Cyrielle; Mialot, Antoine; Quéinnec, Eric; le Guyader, Hervé; Manuel, Michaël

    2013-01-01

    Signalling through the Wnt family of secreted proteins originated in a common metazoan ancestor and greatly influenced the evolution of animal body plans. In bilaterians, Wnt signalling plays multiple fundamental roles during embryonic development and in adult tissues, notably in axial patterning, neural development and stem cell regulation. Studies in various cnidarian species have particularly highlighted the evolutionarily conserved role of the Wnt/β-catenin pathway in specification and patterning of the primary embryonic axis. However in another key non-bilaterian phylum, Ctenophora, Wnts are not involved in early establishment of the body axis during embryogenesis. We analysed the expression in the adult of the ctenophore Pleurobrachia pileus of 11 orthologues of Wnt signalling genes including all ctenophore Wnt ligands and Fz receptors and several members of the intracellular β-catenin pathway machinery. All genes are strongly expressed around the mouth margin at the oral pole, evoking the Wnt oral centre of cnidarians. This observation is consistent with primary axis polarisation by the Wnts being a universal metazoan feature, secondarily lost in ctenophores during early development but retained in the adult. In addition, local expression of Wnt signalling genes was seen in various anatomical structures of the body including in the locomotory comb rows, where their complex deployment suggests control by the Wnts of local comb polarity. Other important contexts of Wnt involvement which probably evolved before the ctenophore/cnidarian/bilaterian split include proliferating stem cells and progenitors irrespective of cell types, and developing as well as differentiated neuro-sensory structures. PMID:24391946

  4. Development of polarized {sup 3}He filter for polarized neutron experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

    1996-08-01

    A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

  5. Inter-examiner reproducibility of tests for lumbar motor control

    OpenAIRE

    Elkjaer Arne; Remvig Lars; Kjaer Per; Enoch Flemming; Juul-Kristensen Birgit

    2011-01-01

    Abstract Background Many studies show a relation between reduced lumbar motor control (LMC) and low back pain (LBP). However, test circumstances vary and during test performance, subjects may change position. In other words, the reliability - i.e. reproducibility and validity - of tests for LMC should be based on quantitative data. This has not been considered before. The aim was to analyse the reproducibility of five different quantitative tests for LMC commonly used in daily clinical practi...

  6. ON APPROXIMATION BY REPRODUCING KERNEL SPACES IN WEIGHTED Lp SPACES

    Institute of Scientific and Technical Information of China (English)

    Baohuai SHENG

    2007-01-01

    In this paper, we investigate the order of approximation by reproducing kernel spaces on (-1, 1) in weighted Lp spaces. We first restate the translation network from the view of reproducing kernel spaces and then construct a sequence of approximating operators with the help of Jacobi orthogonal polynomials, with which we establish a kind of Jackson inequality to describe the error estimate.Finally, The results are used to discuss an approximation problem arising from learning theory.

  7. Reproducible Triangular Solvers for High-Performance Computing

    OpenAIRE

    Iakymchuk, Roman; Defour, David; Collange, Sylvain; Graillat, Stef

    2015-01-01

    On modern parallel architectures, floating-point computations may become non-deterministic and, therefore, non-reproducible mainly due to non-associativity of floating-point operations. We propose an algorithm to solve dense triangular systems by leveraging the standard parallel triangular solver and our, recently introduced, multi-level exact summation approach. Finally, we present implementations of the proposed fast repro-ducible triangular solver and results on recent NVIDIA GPUs.

  8. The fabrication of reproducible superconducting scanning tunneling microscope tips

    OpenAIRE

    Naaman, O.; Teizer, W.; Dynes, R. C.

    2000-01-01

    Superconducting scanning tunneling microscope tips have been fabricated with a high degree of reproducibility. The fabrication process relies on sequential deposition of superconducting Pb and a proximity-coupled Ag capping layer onto a Pt/Ir tip. The tips were characterized by tunneling into both normal-metal and superconducting films. The simplicity of the fabrication process, along with the stability and reproducibility of the tips, clear the way for tunneling studies with a well-character...

  9. Validity and reproducibility of a Spanish dietary history

    OpenAIRE

    Guallar-Castillón, Pilar; Sagardui-Villamor, Jon; Balboa-Castillo, Teresa; Sala-Vila, Aleix; Ariza Astolfi, Mª José; Sarrión Pelous, Mª Dolores; León-Muñoz, Luz María; Graciani, Auxiliadora; Laclaustra, Martín; Benito, Cristina; Banegas, José Ramón; Rodríguez Artalejo, Fernando

    2014-01-01

    Objective: To assess the validity and reproducibility of food and nutrient intake estimated with the electronic diet history of ENRICA (DH-E), which collects information on numerous aspects of the Spanish diet. Methods: The validity of food and nutrient intake was estimated using Pearson correlation coefficients between the DH-E and the mean of seven 24-hour recalls collected every 2 months over the previous year. The reproducibility was estimated using intraclass correlation coef...

  10. Single and multiband THz Metamaterial Polarizers

    OpenAIRE

    Sangala, Bagvanth Reddy; Nagarajan, Arvind; Deshmukh, Prathmesh; Surdi, Harshad; Rana, Goutam; Gopal, Achanta Venu; Prabhu, S. S.

    2015-01-01

    We report single and multiband linear polarizers for terahertz (THz) frequencies using cut-wire metamaterials (MM). The MMs are designed by finite element method, fabricated by electron beam lithography, and characterized by THz time-domain spectroscopy. The MM unit cells consist of single or multiple length cut-wire pads of gold on semi-insulating Gallium Arsenide for single or multiple band polarizers. The dependence of the resonance frequency of the single band polarizer on the length of t...

  11. The positive-polarization of cometary comae

    Science.gov (United States)

    Zubko, Evgenij; Videen, Gorden; Hines, Dean C.; Shkuratov, Yuriy

    2016-04-01

    We examine the dispersion of the degree of linear polarization P in comets at phase angle ~90° where the maximum amplitude of positive polarization Pmax occurs. The range of polarization observed in comets is from 7% up to more than 30%, and this cannot be explained through depolarization by gaseous emissions. Instead, we suggest that the observed dispersion of P results from different properties in cometary dust. We simulate the spectral polarimetric observations of comets using model agglomerated debris particles. The vast majority of observations can be reproduced with a mixture of weakly absorbing and highly absorbing agglomerated debris particles, which obey the same power-law size distribution. Within this extremely simple approach, polarization at side-scattering angles in a given comet is governed by the relative abundance of weakly and strongly absorbing particles. We find that in comets with the highest polarization, the weakly absorbing particles appear in proportions of only 14-23% by volume; whereas, in comets with the lowest polarization Pmax, their abundance is much greater, 82-95%. We conclude that the polarization at side-scattering angles unambiguously measures the relative abundance of Mg-rich silicates and refractory organics or amorphous carbon in comets. We put forth a hypothesis that low Pmax could be an indicator for presence of a well-developed refractory surface layer covering cometary nucleus.

  12. On The Reproducibility of Seasonal Land-surface Climate

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, T J

    2004-10-22

    The sensitivity of the continental seasonal climate to initial conditions is estimated from an ensemble of decadal simulations of an atmospheric general circulation model with the same specifications of radiative forcings and monthly ocean boundary conditions, but with different initial states of atmosphere and land. As measures of the ''reproducibility'' of continental climate for different initial conditions, spatio-temporal correlations are computed across paired realizations of eleven model land-surface variables in which the seasonal cycle is either included or excluded--the former case being pertinent to climate simulation, and the latter to seasonal anomaly prediction. It is found that the land-surface variables which include the seasonal cycle are impacted only marginally by changes in initial conditions; moreover, their seasonal climatologies exhibit high spatial reproducibility. In contrast, the reproducibility of a seasonal land-surface anomaly is generally low, although it is substantially higher in the Tropics; its spatial reproducibility also markedly fluctuates in tandem with warm and cold phases of the El Nino/Southern Oscillation. However, the overall degree of reproducibility depends strongly on the particular land-surface anomaly considered. It is also shown that the predictability of a land-surface anomaly implied by its reproducibility statistics is consistent with what is inferred from more conventional predictability metrics. Implications of these results for climate model intercomparison projects and for operational forecasts of seasonal continental climate also are elaborated.

  13. IL-33 promotes GATA-3 polarization of gut-derived T cells in experimental and ulcerative colitis

    DEFF Research Database (Denmark)

    Seidelin, Jakob Benedict; Coskun, Mehmet; Kvist, Peter Helding; Holm, Thomas Lindebo; Holgersen, Kristine; Nielsen, Ole Haagen

    2015-01-01

    BACKGROUND: In the respiratory mucosa, interleukin (IL)-33, has been shown to enhance T helper 2 (TH2)-type responses through the master regulatory gene GATA-3. IL-33 is upregulated in ulcerative colitis (UC), and the aim was to assess if IL-33 holds a similar key position in the shaping of the...... were isolated from PAC IL-10 -/- mice and stimulated with IL-33.RESULTS: The colonic IL-33 expression was significantly upregulated all forms of colitis (P < 0.01) and correlated with disease severity score and inflammation (P < 0.001), and with GATA-3 expression levels (P < 0.01); no correlation with...... the TH1-specific T-bet expression was observed. MesLN T cells stimulated with IL-33 had increased GATA-3 expression, and showed an IL-33 dose-dependent increase in secreted TH2-type cytokines, whereas this effect was abolished by blocking IL-33 signaling. The non-TH2-type cytokine IL-17 was...

  14. Scheme of adaptive polarization filtering based on Kalman model

    Institute of Scientific and Technical Information of China (English)

    Song Lizhong; Qi Haiming; Qiao Xiaolin; Meng Xiande

    2006-01-01

    A new kind of adaptive polarization filtering algorithm in order to suppress the angle cheating interference for the active guidance radar is presented. The polarization characteristic of the interference is dynamically tracked by using Kalman estimator under variable environments with time. The polarization filter parameters are designed according to the polarization characteristic of the interference, and the polarization filtering is finished in the target cell. The system scheme of adaptive polarization filter is studied and the tracking performance of polarization filter and improvement of angle measurement precision are simulated. The research results demonstrate this technology can effectively suppress the angle cheating interference in guidance radar and is feasible in engineering.

  15. Modelling soil erosion at European scale: towards harmonization and reproducibility

    Science.gov (United States)

    Bosco, C.; de Rigo, D.; Dewitte, O.; Poesen, J.; Panagos, P.

    2015-02-01

    Soil erosion by water is one of the most widespread forms of soil degradation. The loss of soil as a result of erosion can lead to decline in organic matter and nutrient contents, breakdown of soil structure and reduction of the water-holding capacity. Measuring soil loss across the whole landscape is impractical and thus research is needed to improve methods of estimating soil erosion with computational modelling, upon which integrated assessment and mitigation strategies may be based. Despite the efforts, the prediction value of existing models is still limited, especially at regional and continental scale, because a systematic knowledge of local climatological and soil parameters is often unavailable. A new approach for modelling soil erosion at regional scale is here proposed. It is based on the joint use of low-data-demanding models and innovative techniques for better estimating model inputs. The proposed modelling architecture has at its basis the semantic array programming paradigm and a strong effort towards computational reproducibility. An extended version of the Revised Universal Soil Loss Equation (RUSLE) has been implemented merging different empirical rainfall-erosivity equations within a climatic ensemble model and adding a new factor for a better consideration of soil stoniness within the model. Pan-European soil erosion rates by water have been estimated through the use of publicly available data sets and locally reliable empirical relationships. The accuracy of the results is corroborated by a visual plausibility check (63% of a random sample of grid cells are accurate, 83% at least moderately accurate, bootstrap p ≤ 0.05). A comparison with country-level statistics of pre-existing European soil erosion maps is also provided.

  16. Modelling soil erosion at European scale: towards harmonization and reproducibility

    Directory of Open Access Journals (Sweden)

    C. Bosco

    2014-04-01

    Full Text Available Soil erosion by water is one of the most widespread forms of soil degradation. The loss of soil as a result of erosion can lead to decline in organic matter and nutrient contents, breakdown of soil structure and reduction of the water holding capacity. Measuring soil loss across the whole landscape is impractical and thus research is needed to improve methods of estimating soil erosion with computational modelling, upon which integrated assessment and mitigation strategies may be based. Despite the efforts, the prediction value of existing models is still limited, especially at regional and continental scale. A new approach for modelling soil erosion at large spatial scale is here proposed. It is based on the joint use of low data demanding models and innovative techniques for better estimating model inputs. The proposed modelling architecture has at its basis the semantic array programming paradigm and a strong effort towards computational reproducibility. An extended version of the Revised Universal Soil Loss Equation (RUSLE has been implemented merging different empirical rainfall-erosivity equations within a climatic ensemble model and adding a new factor for a better consideration of soil stoniness within the model. Pan-European soil erosion rates by water have been estimated through the use of publicly available datasets and locally reliable empirical relationships. The accuracy of the results is corroborated by a visual plausibility check (63% of a random sample of grid cells are accurate, 83% at least moderately accurate, bootstrap p ≤ 0.05. A comparison with country level statistics of pre-existing European maps of soil erosion by water is also provided.

  17. Penta prism laser polarizer.

    Science.gov (United States)

    Lotem, H; Rabinovitch, K

    1993-04-20

    A novel type of laser prism polarizer is proposed. The polarizer is characterized by a high transmission efficiency, a high optical damage threshold, and a high extinction ratio. The polarizer is shaped like a regular penta prism and, thus, it is a constant deviation angle device. Polarization effects occur upon the two internal cascade reflections in the prism. Anisotropic and Isotropic types of the polarizer are discussed. The isotropic polarizer is a prism made of a high refractive-index glass coated by multilayer polarization-type dielectric coatings. Efficient s-state polarization is obtained because of p-state leakage upon the two internal cascade reflections. The anisotropic polarizer is made of a birefringent crystal in which angular polarization splitting is obtained by the bireflectance (double-reflection) effect. Fanning of a laser beam into up to eight polarized beams is possible in a prism made of a biaxial crystal. PMID:20820335

  18. Vacuum polarization in Schwarzschild spacetime: Boulware vacuum

    International Nuclear Information System (INIS)

    Approximate regularized expectation values of the field fluctuation (Φ2)reg and the stress-energy tensor (Tμν)reg of the massless, conformally invariant, scalar field in the Boulware vacuum state in Schwarzschild spacetime are constructed by means of Hadamard regularization. It is shown that reconstruction of the characteristics of the vacuum polarization from its asymptotic behaviour leads to formulas that satisfactorily reproduce existing approximate expressions and closely follow exact numerical calculations. (author)

  19. Full Stokes polarization imaging camera

    Science.gov (United States)

    Vedel, M.; Breugnot, S.; Lechocinski, N.

    2011-10-01

    Objective and background: We present a new version of Bossa Nova Technologies' passive polarization imaging camera. The previous version was performing live measurement of the Linear Stokes parameters (S0, S1, S2), and its derivatives. This new version presented in this paper performs live measurement of Full Stokes parameters, i.e. including the fourth parameter S3 related to the amount of circular polarization. Dedicated software was developed to provide live images of any Stokes related parameters such as the Degree Of Linear Polarization (DOLP), the Degree Of Circular Polarization (DOCP), the Angle Of Polarization (AOP). Results: We first we give a brief description of the camera and its technology. It is a Division Of Time Polarimeter using a custom ferroelectric liquid crystal cell. A description of the method used to calculate Data Reduction Matrix (DRM)5,9 linking intensity measurements and the Stokes parameters is given. The calibration was developed in order to maximize the condition number of the DRM. It also allows very efficient post processing of the images acquired. Complete evaluation of the precision of standard polarization parameters is described. We further present the standard features of the dedicated software that was developed to operate the camera. It provides live images of the Stokes vector components and the usual associated parameters. Finally some tests already conducted are presented. It includes indoor laboratory and outdoor measurements. This new camera will be a useful tool for many applications such as biomedical, remote sensing, metrology, material studies, and others.

  20. Polarization in free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Papadichev, V.A. [Lebedev Physical Institute, Moscow (Russian Federation)

    1995-12-31

    Polarization of electromagnetic radiation is required very often in numerous scientific and industrial applications: studying of crystals, molecules and intermolecular interaction high-temperature superconductivity, semiconductors and their transitions, polymers and liquid crystals. Using polarized radiation allows to obtain important data (otherwise inaccessible) in astrophysics, meteorology and oceanology. It is promising in chemistry and biology for selective influence on definite parts of molecules in chain synthesis reactions, precise control of various processes at cell and subcell levels, genetic engineering etc. Though polarization methods are well elaborated in optics, they can fail in far-infrared, vacuum-ultraviolet and X-ray regions because of lack of suitable non-absorbing materials and damaging of optical elements at high specific power levels. Therefore, it is of some interest to analyse polarization of untreated FEL radiation obtained with various types of undulators, with and without axial magnetic field. The polarization is studied using solutions for electron orbits in various cases: plane or helical undulator with or without axial magnetic field, two plane undulators, a combination of right- and left-handed helical undulators with equal periods, but different field amplitudes. Some examples of how a desired polarization (elliptical circular or linear) can be obtained or changed quickly, which is necessary in many experiments, are given.