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OALib Journal期刊

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Muscle cells challenged with saturated fatty acids mount an autonomous inflammatory response that activates macrophages
Nicolas J Pillon, Karen Arane, Philip J Bilan, Tim T Chiu, Amira Klip
Cell Communication and Signaling , 2012, DOI: 10.1186/1478-811x-10-30
Abstract: We used a cell culture approach to investigate the vectorial crosstalk between muscle cells and macrophages upon exposure to physiological, low levels of saturated and unsaturated fatty acids. Inflammatory pathway activation and cytokine expression were analyzed in L6 muscle cells expressing myc-tagged GLUT4 (L6GLUT4myc) exposed to 0.2 mM palmitate or palmitoleate. Conditioned media thereof, free of fatty acids, were then tested for their ability to activate RAW264.7 macrophages.Palmitate -but not palmitoleate- induced IL-6, TNFα and CCL2 expression in muscle cells, through activation of the NF-κB pathway. Palmitate (0.2 mM) alone did not induce insulin resistance in muscle cells, yet conditioned media from palmitate-challenged muscle cells selectively activated macrophages towards a pro-inflammatory phenotype.These results demonstrate that low concentrations of palmitate activate autonomous inflammation in muscle cells to release factors that turn macrophages pro-inflammatory. We hypothesize that saturated fat-induced, low-grade muscle cell inflammation may trigger resident skeletal muscle macrophage polarization, possibly contributing to insulin resistance in vivo.Obesity is associated with chronic activation of the immune system. In response to high fat diet, the fat tissue attracts immune cells that cause low, sustained inflammation responsible for making the body resistant to insulin. Recent studies show that inflammation also happens in muscle, but its origin and consequence for the development of type 2 diabetes are not understood.We used cells in culture to investigate the communication between muscle and immune cells upon exposure to low levels of a saturated fatty acid (palmitate as in western diet) or an unsaturated fatty acid (palmitoleate, as in Mediterranean diet). We analyzed the effects of these fatty acids on muscle inflammation and next collected the solution surrounding these cells (called conditioned media), and tested its ability to activate imm
Testing hydrostatic equilibrium in galaxy cluster MS 2137
I-Non Tim Chiu,Sandor M. Molnar
Physics , 2012, DOI: 10.1088/0004-637X/756/1/1
Abstract: We test the assumption of strict hydrostatic equilibrium in galaxy cluster MS2137.3-2353 (MS 2137) using the latest CHANDRA X-ray observations and results from a combined strong and weak lensing analysis based on optical observations. We deproject the two-dimensional X-ray surface brightness and mass surface density maps assuming spherical and spheroidal dark matter distributions. We find a significant, 40%-50%, contribution from non-thermal pressure in the core assuming a spherical model. This non-thermal pressure support is similar to what was found by Molnar et al. (2010) using a sample of massive relaxed clusters drawn from high resolution cosmological simulations. We have studied hydrostatic equilibrium in MS 2137 under the assumption of elliptical cluster geometry adopting prolate models for the dark matter density distribution with different axis ratios. Our results suggest that the main effect of ellipticity (compared to spherical models) is to decrease the non-thermal pressure support required for equilibrium at all radii without changing the distribution qualitatively. We find that a prolate model with an axis ratio of 1.25 (axis in the line of sight over perpendicular to it) provides a physically acceptable model implying that MS 2137 is close to hydrostatic equilibrium at about 0.04-0.15 Rvir and have an about 25% contribution from non-thermal pressure at the center. Our results provide further evidence that there is a significant contribution from non-thermal pressure in the core region of even relaxed clusters, i.e., the assumption of hydrostatic equilibrium is not valid in this region, independently of the assumed shape of the cluster.
Application of Remote Sensing and GIS for Modeling and Assessment of Land Use/Cover Change in Amman/Jordan  [PDF]
Jawad T. Al-Bakri, Mohmmad Duqqah, Tim Brewer
Journal of Geographic Information System (JGIS) , 2013, DOI: 10.4236/jgis.2013.55048
Abstract: Modeling and assessment of land use/cover and its impacts play a crucial role in land use planning and formulation of sustainable land use policies. In this study, remote sensing data were used within geographic information system (GIS) to map and predict land use/cover changes near Amman, where half of Jordan’s population is living. Images of Landsat TM, ETM+ and OLI were processed and visually interpreted to derive land use/cover for the years 1983, 1989, 1994, 1998, 2003 and 2013. The output maps were analyzed by using GIS and cross-tabulated to quantify land use/cover changes for the different periods. The main changes that altered the character of land use/cover in the area were the expansion of urban areas and the recession of forests, agricultural areas (after 1998) and rangelands. The Markov chain was used to predict future land use/cover, based on the historical changes during 1983-2013. Results showed that prediction of land use/cover would depend on the time interval of the multi-temporal satellite imagery from which the probability of change was derived. The error of prediction was in the range of 2%-5%, with more accurate prediction for urbanization and less accurate prediction for agricultural areas. The trends of land use/cover change showed that urban areas would expand at the expense of agricultural land and would form 33% of the study area (50 km×60 km) by year 2043. The impact of these land use/cover changes would be the increased water demand and wastewater generation in the future.

Slow Growing Pre-Weaning Piglets Have Altered Adipokine Gene Expression  [PDF]
Tim G. Ramsay, M. J. Stoll, T. J. Caperna
Open Journal of Animal Sciences (OJAS) , 2014, DOI: 10.4236/ojas.2014.44024
Abstract: Growth rate affects adipose tissue development and variations in growth rate may potentially impact adipokine expression. Samples of subcutaneous (SQ) and perirenal (PR) adipose tissues and longissimus muscle were collected at day 21 of age from the fastest and slowest growing piglets within seven litters. Reverse transcription and real-time PCR were used to quantify adipokine mRNA abundance. Leptin, adiponectin, tumor necrosis factor α (TNFα ) and lipoprotein lipase (LPL) mRNA abundance were lower in SQ from slow growing piglets (SGP) than in fast growing piglets (FGP, P < 0.05). Macrophage migration inhibitory factor and TNFα gene expression were reduced in PR from SGP in comparison to FGP (P < 0.05). Interleukin 1β (IL1β), IL15 and LPL were increased in the longissimus of SGP relative to FGP (P < 0.05). Analysis of mRNA abundance for these adipokines within adipose tissue at day 21 of age demonstrated that the effect of growth rate on adipokine expression varies among different adipokines and the internal and external sites of adipose tissue deposition (PR versus SQ). The increase in longissimus expression of LPL and IL15 suggests that nutrient partitioning for energy use may be greater in the skeletal muscle of the SGP.
Insulin receptor signaling in the development of neuronal structure and function
Shu-Ling Chiu, Hollis T Cline
Neural Development , 2010, DOI: 10.1186/1749-8104-5-7
Abstract: The human brain is made up of billions of neurons assembled into sophisticated circuits. Information received from sensory neurons is processed by neurons within distinct circuits to generate specific functional outputs, including cognitive decisions and behavior. A fascinating problem is how these huge numbers of neurons establish precise connections to assemble complex circuits during development. The neuron, the functional unit of the brain circuit, is a highly specialized cell composed of the cell body, the dendrite and the axon. The structure of the dendrite determines where and how an individual neuron can receive and integrate information from afferent neurons, whereas the morphology of the axon determines where processed information is sent to efferent neurons. Sites of contacts between the axon and dendrite, or synapses, mediate communication between neurons for proper information flow within the neuronal circuit. We will first review the current understanding of cellular and molecular mechanisms underlying synapse and dendrite development, then focus on recent evidence suggesting a function for insulin receptor signaling in circuit function and pathological brain diseases.The number of synaptic contacts and the efficacy of synaptic transmission in the brain are dynamic throughout development and adulthood [1-3]. These dynamics are crucial for neurons to optimize connections in brain circuits during development. Synaptic plasticity is also important to optimize neuronal function in adults, for example, to adapt to our changing environment and to allow memories to form. Synapse development is a series of distinct processes, including synapse formation, synapse maturation and synapse maintenance. The mechanisms that regulate each of these processes are just starting to be unraveled.Synapses are specialized junctions between neurons where the presynaptic axon terminal is packed with synaptic vesicles and vesicle release machinery and the postsynaptic dendritic
Effects of neutrino temperatures and mass hierarchies on the detection of supernova neutrinos
Shao-Hsuan Chiu,T. K. Kuo
Physics , 1999, DOI: 10.1103/PhysRevD.61.073015
Abstract: Possible outcomes of neutrino events at both Super-Kamiokande and SNO for a type-II supernova are analyzed considering the uncertainties in SN neutrino spectra (temperature) at emission, which may complicate the interpretation of the observed events. With the input of parameters deduced from the current solar and atmospheric experiments, consequences of direct-mass hierarchy $m_{\nu_{\tau}} \gg m_{\nu_{\mu}} > m_{\nu_{e}}$ and inverted-mass hierarchy $m_{\nu_{e}} > m_{\nu_{\mu}} \gg m_{\nu_{\tau}}$ are investigated. Even if the $\nu$ temperatures are not precisely known, we found that future experiments are likely to be able to separate the currently accepted solutions to the solar neutrino problem (SNP): large angle MSW, small angle MSW, and the vacuum oscillation, as well as to distinguish between the direct and inverted mass hierarchies of the neutrinos.
Stellar Atmospheres Near an AGN: The Importance of Radiation Pressure from Trapped Lyman-alpha Photons
Weihsueh A. Chiu,B. T. Draine
Physics , 1998,
Abstract: We derive an analytic expression for the intensity of resonance-line radiation ``trapped'' in a semi-infinite medium. Given a source function and destruction probability per scattering, the radiation pressure due to trapped photons can be calculated by numerically integrating over analytic functions. We apply this formalism to a plane-parallel model stellar atmosphere to calculate the radiation pressure due to Lyman-alpha photons produced following absorption of UV and X-rays from an AGN. For low surface gravity stars near the AGN (g~10 cm/sec^2, r~0.25 pc), we find that the pressure due to Lyman-alpha photons becomes an appreciable fraction of that required for hydrostatic support. If the broad emission line emitting gas in AGNs and QSOs consists of stellar outflows, it may be driven, in part, by Lyman-alpha pressure.
Thomas precession angle and spinor algebra
Shao-Hsuan Chiu,T. K. Kuo
Physics , 2000,
Abstract: See math-ph/0205036 for an expanded version.
Lorentz transformation and vector field flows
Shao-Hsuan Chiu,T. K. Kuo
Mathematics , 2002, DOI: 10.1088/0305-4470/36/2/317
Abstract: The parameter changes resulting from a combination of Lorentz transformation are shown to form vector field flows. The exact, finite Thomas rotation angle is determined and interpreted intuitively. Using phase portraits, the parameters evolution can be clearly visualized. In addition to identifying the fixed points, we obtain an analytic invariant, which correlates the evolution of parameters.
Transforming Media Markets: The Cases of Malaysia and Singapore
Kenyon, Andrew T.,Marjoribanks, Tim
Australian Journal of Emerging Technologies and Society , 2007,
Abstract: This paper examines contemporary transformations in media markets in Malaysia and Singapore. In both countries, dominant models of ‘old’ media-government relations are being contested by the emergence of ‘new’ online and independent media. Our analysis is grounded in new institutional approaches towards the study of news media and political communication. We argue that while legislation and law, in particular defamation law, and informal and formal organisational relations influence the possibility of public debate through the media, internet-based media are emerging as a potentially critical new voice in journalism in both countries. At the same time, analyses of these potentials need to avoid technological determinism. Rather, there is a need to examine the social, political and economic contexts, and the media markets, in which the technologies are emerging.
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