Regulatory T cells (Tregs) are essential for the establishment and maintenance of immune tolerance, suggesting a potential therapeutic role for Tregs in transplantation. However, Treg administration alone is insufficient in inducing long-term allograft survival in normal hosts, likely due to the high frequency of alloreactive T cells. We hypothesized that a targeted reduction of alloreactive T effector cells would allow a therapeutic window for Treg efficacy. Here we show that preconditioning recipient mice with donor-specific transfusion followed by cyclophosphamide treatment deleted 70-80% donor-reactive T cells, but failed to prolong islet allograft survival. However, infusion of either 5 × 10(6) Tregs with direct donor reactivity or 25 × 10(6) polyclonal Tregs led to indefinite survival of BALB/c islets in more than 70% of preconditioned C57BL/6 recipients. Notably, protection of C3H islets in autoimmune nonobese diabetic mice required islet autoantigen-specific Tregs together with polyclonal Tregs. Treg therapy led to significant reduction of CD8(+) T cells and concomitant increase in endogenous Tregs among graft-infiltrating cells early after transplantation. Together, these results demonstrate that reduction of the donor-reactive T cells will be an important component of Treg-based therapies in transplantation.

The bioactive molecule sphingosine-1-phosphate (S1P) activates five recognized G-protein coupled receptors (S1P₁₋₅) to affect various tissues, including myocardium. Activation of these receptors and the ability to affect functional responses including differentiation, migration, contraction, and ionic currents in isolated cardiac fibroblasts (CFb) and myocytes was investigated. CFb are essential components of myocardium, and study of their cell signaling and physiology is required for a number of emerging disciplines. However, in order to conduct meaningful studies on CFb, methods for selective, reproducible cell isolations are necessary. A protocol was therefore developed that significantly reduced resident macrophage levels in CFb isolates and utilized more CFb- specific markers, instead of, or in addition to, more commonly used cytoskeletal markers. Primary isolated, purified mouse CFb express predominantly S1P₁₋₃; however, the relative levels of these receptor subtypes are modulated with time and by culture conditions. Co-culture with macrophages altered CFb S1P receptor levels relative to controls. Further investigations using known macrophage -secreted factors (e.g. TFG[beta]1, TNF[alpha], and PDGF- BB) all altered S1P receptor subtypes. Low serum concentrations increased S1P₂, which was diminished using a Rho-associated protein kinase inhibitor. Similarly, elevated S1P₃ levels by PDGF-BB were diminished using a Rac1 inhibitor. S1P₂ and S1P₃ (which activate Rho and Rac pathways, respectively) regulate cell migration, and CFb isolated from S1P₃-null mice had reduced migration. These results highlight the importance of demonstrating CFb culture purity in functional studies of S1P and present conditions that modulate S1P receptor expression in CFb. CFb were characterized using novel patch-clamping technology platforms to assess potassium channel currents and the effect of S1P on CFb electrophysiology. Both Kv and Kir currents were identified by conventional and patch -on-a-chip platforms; however, chip platforms were more likely to activate mechanosensitive ion channels. S1P strongly activated both inward and outward currents in adult rat CFb. Lastly, mouse ventricular myoycte contractility was investigated experimentally and through mathematical modeling to characterize signaling pathways involved in S1P-regulated negative inotropy. S1P reduced cell shortening via S1P₁ and S1P₃. In particular, S1P₁ reduced L-type calcium channel activity and activated an acetylcholine-like potassium current to alter action potential duration and intracellular calcium concentrations

Oil shale, which comprises abundant organic matter called kerogen, is a vast energy source. Pyrolysis of kerogen in oil shales releases recoverable hydrocarbons. Here we describe the pyrolysis of kerogen using an in-situ upgrading process, which is applicable to the majority of oil shales. The pyrolysis is represented by six kinetic reactions resulting in 10 components and four phases. Expanding Texas A&M Flow and Transport Simulator (TAMU FTSim), which is a variant of TOUGH + simulator (Moridis and Freeman 2014), we develop a fully functional capability that describes kerogen pyrolysis and accompanying system changes with a minimum of simplifications and assumptions. The simulator describes coupled process of mass transport and heat flow through porous and fractured media and includes all known physics and chemistry of reservoir systems. The simulator involves a total of 15 thermophysical states and all transitions between them and computes a simultaneous solution of 11 mass and energy balance equations per element. The simulator solves the equations in a fully implicit manner by solving Jacobian matrix equations using Newton-Raphson iteration method. To conduct a realistic simulation, we account for geological structure of oil shale reservoirs and physical properties of bulk oil shale rock. In addition, we consider interaction between fluids and porous media, diverse equations of state for computation of fluid properties, and numerical modeling of fractured media. We intensively validate the simulator by reproducing the field production data from Shell In-situ Conversion Process implemented in Green River Formation. We conduct sensitivity analyses of diverse reservoir parameters, such as presence or absence of a pre-existing fracture system, oil shale grade, permeability of the pre-existing fracture system, and thermal conductivity of a reservoir formation. We analyze the effects of the reservoir parameters on productivity and find a model that shows a similar production rate curve to the field production. The simulator is successfully validated and provides a powerful tool to evaluate effectiveness of in-situ upgrading processes and corresponding amount of recoverable hydrocarbons.

The creep rate of Sn solder joints is noticeably affected by joint metallization. Cu|Sn|Cu joints have significantly higher creep rates than Ni|Sn|Cu joints, which, in turn, have higher creep rates than Ni|Sn|Ni joints. Replacing Ni by Cu on both substrates increases the creep rate at 333 K (60 °C) by roughly an order of magnitude. The increased creep rate appears with no apparent change in the dominant creep mechanism; the change in the constitutive equation for creep (the Dorn equation) is in the pre-exponential factor. The decreased creep rate on substituting Ni is accompanied by an increase in the hardness of the polygranular solder but a decrease in the nanohardness of the grain interiors. The source of the strong influence of the Ni substrate appears to be the introduction of an array of Ni3Sn4 intermetallic precipitates along the grain boundaries. These precipitates inhibit grain boundary sliding, boundary reconfiguration, and grain growth during creep. The intermediate creep rate of the asymmetric Ni|Sn|Cu joint has two causes: a decrease in grain boundary mobility due to precipitate decoration and a restriction in the free volume of the joint due to rapid intermetallic growth from the substrate on the Ni side. The sources of this anomalous intermetallic growth are discussed.

Oil shale, which is composed of abundant organic matter called kerogen, is a vast energy source. Pyrolysis of kerogen in oil shales releases recoverable hydrocarbons. Here, we describe the pyrolysis of kerogen with an in-situ upgrading process, which is applicable to the majority of oil shales. The pyrolysis is represented by six kinetic reactions resulting in 10 components and four phases. Expanding the Texas A&M Flow and Transport Simulator (FTSim), which is a variant of the TOUGH +simulator (Moridis 2014), we develop a fully functional capability that describes kerogen pyrolysis and accompanying system changes. The simulator describes the coupled process of mass transport and heat flow through porous and fractured media and includes physical and chemical phenomena of reservoir systems. The simulator involves a total of 15 thermophysical states and all transitions between them and computes a simultaneous solution of 11 mass- and energy-balance equations per element. The simulator solves the equations in a fully implicit manner by solving Jacobian matrix equations with the Newton-Raphson iteration method. To conduct a realistic simulation, we account for geological structure of oil-shale reservoirs and physical properties of bulk-oil shale rocks by considering phases and components in the pores. In addition, we involve interaction between fluids and porous media, diverse equations of state (EOSs) for computation of fluid properties, and numerical modeling of fractured media. We intensively reproduce the field-production data of Shell Insitu Conversion Process (ICP) implemented in the Green River formation by conducting sensitivity analyses for the diverse reservoir parameters, such as initial effective porosity of the matrix, oil-shale grade, and the spacing of the natural-fracture network. We analyze the effect of each reservoir parameter on the hydrocarbon productivity and product selectivity. The simulator provides a powerful tool to quantitatively evaluate production behavior and dynamic-system changes during in-situ upgrading of oil shales and subsequent fluid production by thoroughly describing a reservoir model, phases and components, phase behavior, phase properties, and evolution of porosity and permeability.

Research on human immune responses frequently involves the use of peripheral blood mononuclear cells (PBMC) immediately, or at significantly delayed timepoints, after collection. This requires PBMC isolation from whole blood and cryopreservation for some a