CD47 in the Brain and Neurodegeneration: An Update on the Role in Neuroinflammatory Pathways

CD47 is a receptor belonging to the immunoglobulin (Ig) superfamily and broadly expressed on cell membranes. Through interactions with ligands such as SIRPα, TSP-1, integrins, and SH2-domain bearing protein tyrosine phosphatase substrate-1 (SHPS-1), CD47 regulates numerous functions like cell adhesion, proliferation, apoptosis, migration, homeostasis, and the immune system. In this aspect, previous research has shown that CD47 modulates phagocytosis via macrophages, the transmigration of neutrophils, and the activation of T-cells, dendritic cells, and B-cells. Moreover, several studies have reported the increased expression of the CD47 receptor in a variety of diseases, including acute lymphoblastic leukemia (ALL), chronic myeloid leukemia, non-Hodgkin’s lymphoma (NHL), multiple myeloma (MM), bladder cancer, acute myeloid leukemia (AML), Gaucher disease, Multiple Sclerosis and stroke among others. The ubiquitous expression of the CD47 cell receptor on most resident cells of the CNS has previously been established through different methodologies. However, there is little information concerning its precise functions in the development of different neurodegenerative pathologies in the CNS. Consequently, further research pertaining to the specific functions and roles of CD47 and SIRP is required prior to its exploitation as a druggable approach for the targeting of various neurodegenerative diseases that affect the human population. The present review attempts to summarize the role of both CD47 and SIRP and their therapeutic potential in neurodegenerative disorders.     

Experimental and theoretical studies of convective heat transfer in a cylindrical porous medium

Convective heat transfer at constant heat flux through unconsolidated porous media has been studied both experimentally and theoretically. Heat transfer measurements have been performed for convective heat transfer over a wide range of operational parameters at constant heat fluxes. In addition to heat transfer coefficients, pressure drop and temperature profiles both in radial and axial direction have been recorded. The equations of motion and energy which account for the non-Darcian effect are used to describe the flow and convective heat transfer through the porous medium. Mathematical models for the prediction of heat transfer coefficients and temperature profiles are presented which predict the experimental data with good accuracy.     

The critical role of channel cross-sectional area in microchannel flow boiling heat transfer

Experiments are conducted with a perfluorinated dielectric fluid, Fluorinert FC-77, to identify the critical geometric parameters that affect flow boiling heat transfer and flow patterns in microchannels. In recent work by the authors (Harirchian and Garimella, 2009), seven different silicon test pieces containing parallel microchannels of widths ranging from 100 to 5850 μm, all with a depth of 400 μm were tested and it was shown that for a fixed channel depth, the heat transfer coefficient was independent of channel width for microchannels of widths 400 μm and larger, with the flow regimes in these microchannels being similar; nucleate boiling was also found to be dominant over a wide range of heat fluxes. In the present study, experiments are performed with five additional microchannel test pieces with channel depths of 100 and 250 μm and widths ranging from 100 to 1000 μm. Flow visualizations are performed using a high-speed digital video camera to determine the flow regimes, with simultaneous local measurements of the heat transfer coefficient and pressure drop. The aim of the present study is to investigate as independent parameters the channel width and depth as well as the aspect ratio and cross-sectional area on boiling heat transfer in microchannels, based on an expanded database of experimental results. The flow visualizations and heat transfer results show that the channel cross-sectional area is the important governing parameter determining boiling mechanisms and heat transfer in microchannels. For channels with cross-sectional area exceeding a specific value, nucleate boiling is the dominant mechanism and the boiling heat transfer coefficient is independent of channel dimensions; below this threshold value of cross-sectional area, vapor confinement is observed in all channels at all heat fluxes, and the heat transfer rate increases as the microchannel cross-sectional area decreases before premature dryout occurs due to channel confinement.     

Inhibition of Scale Formation Using Silica Nanoparticle

Because of the wide use of water injection for enhanced oil recovery in the oil fields in order to displace oil into the production well, many reservoirs experience scale deposition problems. Scale formation can cause the production path to be blocked and also cause significant reduction in productivity. One of the most common methods for preventing or lowering the amount of scale formation is applying the scale inhibitors. In this work, silica nanoparticles are used as a scale inhibitor. Conductivity is used as a property of the fluid to show the amount of ion in the solution, leading us to predict the amount of scale formed in the solution. An optimum amount of silica nanoparticles could reduce the rate of conductivity decreasing the solution and consequently lowering the scale deposition, which is the aim of this challenging subject in the oil industry.     

Different methods to calculate heat transfer coefficient in a double-tube heat exchanger: A comparative study

An experimental study performed to compare the results of different methods used in the literature for the calculation of heat transfer coefficient in double-tube heat exchangers. Then, a new fundamental approach was proposed which used the temperature profile and the local heat transfer coefficients. In this method, the heat transfer coefficient has been calculated for the total length of the heat exchanger including developing and fully developed regions. Numerous experimentations have been conducted in a double-tube heat exchanger. A significant difference observed between the results obtained from the suggested approach and those of the previous methods.     

Einfluß der Heizflächenbeschichtung auf den Wärmeübergangskoeffizienten beim Behältersieden von Wasser,Isopropanol, Azeton und deren Mischungen

Zusammenfassung In der vorliegenden Arbeit wird der Wärmeübergang von drei Stahlheizstäben mit unterschiedlicher Oberfläche verglichen. Ein Heizstab wurde mit einer perforierten Messingfolie umhüllt, der zweite mit Teflon beschichtet, während der dritte unbeschichtet verwendet wurde. Als Testflüssigkeiten wurden Wasser, Azeton, Isopropanol und deren Mischungen verwendet.

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The influence of a coating of the heating surface on the heat transfer coefficient during pool boiling of water, isopropanol, acetone and their mixtures

This article compares pool boiling heat transfer from three stainless steel heating rods with different surfaces. One heating rod was covered with a perforated brass foil, one was coated with teflon and the third was used without any coating. Water, acetone, isopropanol and their mixtures were used as test liquids.

     

Thermodynamics, Kinetics, and Hydrodynamics of Mixed Salt Precipitation in Porous Media: Model Development and Parameter Estimation

Demands for hydrocarbon production have been increasing in recent years. Today many oilfields around the world are afflicted by the problem of scaling leading to severe formation damage and hampering of petroleum production from hydrocarbon reservoirs. In current study, a mathematical model for prediction of permeability reduction due to scale deposition is developed based on thermodynamics, kinetics, and hydrodynamics of mixed salt precipitation during flow through porous media. Model predictions are compared with sound experimental data for single deposition of barium sulfate and most importantly, for simultaneous precipitation of barium sulfate and strontium sulfate onto rock surface. Owing to high nonlinearity of the proposed model, kinetic parameters embedded in the mathematical model were tuned employing a new approach based on a hybrid algorithm consisting of particle swarm optimization (PSO) technique and pattern search (PS) algorithm. The average absolute deviations ranging from 1.03 to 9.3 % were observed between model forecasts and experimental data which corroborate the suitability and applicability of the model and also confirm the capability of PSO–PS hybrid algorithm as a highly efficient optimization tool. Estimated values for kinetic parameters are also in accordance with collision theory of chemical reactions.     

Saturated nucleate boiling to binary and ternary mixtures on horizontal cylinder

In this investigation, a large number of experiments have been performed to determine saturated nucleate pool boiling heat transfer coefficients of MEA/water and DEA/water binary mixtures and that of water/MEA/DEA ternary mixtures. These heat transfer coefficients have been measured at atmospheric pressure and over a wide range of heat fluxes and solution concentrations. The heat flux has been varied in 14 different levels from 7 to about 230 kW/m² and amines concentration has been changed in 10 different levels from zero to 84 wt%. Results show that strong reduction of heat transfer coefficient occurs as a result of mass transfer interference in this phenomenon. Furthermore, in this study, all the correlations proposed during the last years for the prediction of nucleate boiling heat transfer coefficient of mixtures have been categorized in three groups. Some experimental results have been compared with the most accurate representatives of these three groups and the corresponding RMS errors have been calculated. Also, impacts of important existing parameters in these correlations like ideal heat transfer coefficient (h_id.) on the prediction have been discussed.