Targeting lemurs against cancer metastasis

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Incentives For Poultry Integrators To Contract Bio-Secure Producers And Implication For Government Indemnification Program

These recent events of H1N1 flu outbreak illustrate the potential ramifications of infectious diseases on modern society and how society responds to these threats. This thesis addresses the specific case of avian influenza in U.S. poultry production. By building an expected utility maximization model for integrators contracting with growers of varying bio-secure levels, one can investigate the relationship between the bio-secure choice of the poultry industry and their production performance. The model is empiricized using the Phoon, Quek, and Huang (PQH) simulation technique to conduct numerical analysis. The model selects the optimal percentage of bio-secure farms for the integrators to contract, output price reductions due to disease outbreak, and different probabilities of disease outbreak. Results allow the examination of whether alternative USDA/APHIS indemnification rules can sufficiently influence integrators willingness to improve their bio-security level

Studies on the effects of short-chain fatty acids on beta cell differentiation and maturation in neonatal porcine islet-like cell clusters

Cell replacement therapy is a realistic option for the treatment and cure of type 1 diabetes. Neonatal porcine islets cell clusters (NPICCs) are considered to represent an unlimited cell source but face some challenges including the strong immunogenicity and the need for the generation of high numbers of excellent quality NPICCs. Since NPICCs are composed of progenitor cells and immature insulin-secreting beta cells, novel strategies to improve in vitro generation of matured beta cells and/or to increase islet numbers is a prerequisite for the near future transfer of xenotransplantation to the clinic. In the present study, NPICCs were isolated from 2-3 days-old piglets to evaluate the effects of three main short-chain fatty acids (SCFA), acetate, propionate and butyrate, on in vitro islet differentiation and beta cell function assessed by real-time quantitative PCR, FACS analysis, immunohistology and glucose-stimulated insulin secretion (GSIS). Butyrate promoted a significant time- and dose-dependent up-regulation in insulin gene expression and an increased beta cell number, whereas acetate or propionate only marginally influenced the beta cell phenotype. The treatment with specific inhibitors of SCFA receptors such as G-protein-coupled receptor GPR41 (β-hydroxybutyrate) and GPR43 (GPLG0974) did not suppress the butyrate-mediated increase of insulin expression. However, the application of specific class I histone deacetylase (HDAC) inhibitors mocetinostat, MS275, FK228 and RGFP996 mimicked butyrate on beta cell differentiation, whereas selective class II HDAC inhibitors (TMP269, MC1568) displayed no effects. These data suggest that the pro-endocrine impact of butyrate is mainly mediated through its HDAC inhibitory activity. The data of the present study suggest that butyrate and class I HDAC inhibitors are important agents to study the mechanisms of beta cell differentiation in porcine islets and produce optimized NPICC cell products for novel cell replacement therapies

Utilizing Converter-Interfaced Sources for Frequency Control with Guaranteed Performance in Power Systems

To integrate renewable energy, converter-interfaced sources (CISs) keep penetrating into power systems and degrade the grid frequency response. Control synthesis towards guaranteed performance is a challenging task. Meanwhile, the potentials of highly controllable converters are far from fully developed. With properly designed controllers the CISs can not only eliminate the negative impacts on the grid, but also provide performance guarantees.First, the wind turbine generator (WTG) is chosen to represent the CISs. An augmented system frequency response (ASFR) model is derived, including the system frequency response model and a reduced-order model of the WTG representing the supportive active power due to the supplementary inputs.Second, the framework for safety verification is introduced. A new concept, region of safety (ROS), is proposed, and the safe switching principle is provided. Two different approaches are proposed to estimate the largest ROS, which can be solved using the sum of squares programming.Third, the critical switching instants for adequate frequency response are obtained through the study of the ASFR model. A safe switching window is discovered, and a safe speed recovery strategy is proposed to ensure the safety of the second frequency dip due to the WTG speed recovery.Fourth, an adaptive safety supervisory control (SSC) is proposed with a two-loop configuration, where the supervisor is scheduled with respect to the varying renewable penetration level. For small-scale system, a decentralized fashion of the SSC is proposed under rational approximations and verified on the IEEE 39-bus system.Fifth, a two-level control diagram is proposed so that the frequency of a microgrid satisfies the temporal logic specifications (TLSs). The controller is configured into a scheduling level and a triggering level. The satisfaction of TLSs will be guaranteed by the scheduling level, and triggering level will determine the activation instant.Finally, a novel model reference control based synthetic inertia emulation strategy is proposed. This novel control strategy ensures precise emulated inertia by the WTGs as opposed to the trial and error procedure of conventional methods. Safety bounds can be easily derived based on the reference model under the worst-case scenario

Radiation Transfer of Models of Massive Star Formation. III. The Evolutionary Sequence

We present radiation transfer (RT) simulations of evolutionary sequences of massive protostars forming from massive dense cores in environments of high surface densities. The protostellar evolution is calculated with a detailed multi-zone model, with the accretion rate regulated by feedback from an evolving disk-wind outflow cavity. Disk and envelope evolutions are calculated self-consistently. In this framework, an evolutionary track is determined by three environmental initial conditions: the initial core mass M_c, the mean surface density of the ambient star-forming clump Sigma_cl, and the rotational-to-gravitational energy ratio of the initial core, beta_c. Evolutionary sequences with various M_c, Sigma_cl, beta_c are constructed. We find that in a fiducial model with M_c=60Msun, Sigma_cl=1 g/cm^2 and beta_c=0.02, the final star formation efficiency >~0.43. For each evolutionary track, RT simulations are performed at selected stages, with temperature profiles, SEDs, and images produced. At a given stage the envelope temperature is highly dependent on Sigma_cl, but only weakly dependent on M_c. The SED and MIR images depend sensitively on the evolving outflow cavity, which gradually wides as the protostar grows. The fluxes at <~100 microns increase dramatically, and the far-IR peaks move to shorter wavelengths. We find that, despite scatter caused by different M_c, Sigma_cl, beta, and inclinations, sources at a given evolutionary stage appear in similar regions on color-color diagrams, especially when using colors at >~ 70 microns, where the scatter due to the inclination is minimized, implying that such diagrams can be useful diagnostic tools of evolutionary stages of massive protostars. We discuss how intensity profiles along or perpendicular to the outflow axis are affected by environmental conditions and source evolution.Comment: 28 pages, 26 figures. Accepted for publication in Ap

Sliding Keys on Inclined Deflecting-cantilevers (SKID) device for application with Post-Tensioned (PT) frames

This thesis presents a novel frictional damping device for application with Post-Tensioned (PT) frames. A conceptual system named a Frictional Sliding on a Sprung Slope (FSSS) system is proposed first. Its mechanical schematisation is presented, and the theoretical hysteretic behaviour is discussed. The FSSS system has a triangular-shaped hysteretic curve with an amplitude-increasing resistance and a zero-activation threshold. Then, an innovative physical realisation of the conceptual FSSS system is presented and named a Sliding Keys on Inclined Deflecting-cantilevers (SKID) device. The device uses the end stiffness of cantilever bars as the “sprung-slope” for generating an amplitude-dependent normal force. The reliability of using cantilever bars is discussed. (Chapter 3)To demonstrate the SKID device, two 1/4 scale-reduced prototypes are designed and manufactured. They have negative unloading stiffness (SKID A) and positive unloading stiffness (SKID B), respectively. By conducting quasi-static cyclic tests, it is found that they exhibited stable and repeatable triangular-shaped hysteretic curves, verifying a satisfactory consistency between the theoretical behaviour and the test results. In addition, SKID configurations having different manufacturing parameters (i.e., friction materials, cantilever bar stiffness and slope angle) are built and tested by both cyclic and fatigue tests to investigate the behaviour sensitivity. (Chapter 4)Chapter 5 presents the application of the SKID device in PT frames (the PT-SKID frames). The theoretical hysteretic performance of the PT-SKID frame is discussed by deriving its analytical formulations. The PT-SKID frame has a dual-triangular-flag-shaped hysteretic curve, featuring a full self-centring capability. Then, three PT frames with and without the SKID device are analysed numerically using OpenSees as a numerical proof-of-concept. Incremental dynamic analyses (IDA) are carried out to explore the contribution of the SKID device. The results show that the device significantly reduces the seismic response of the PT frame and no residual deformations are observed after the earthquake excitations. Additionally, more than 700 one-story one-bay PT frames with different SKID devices (PT-SKID frames) are numerically tested to investigate the dynamic characteristics of the structural system affecting the seismic response. Chapter 6 investigates the linear equivalence of the PT-SKID frames for estimating peak seismic displacement response. The linear equivalent system is constructed by its secant stiffness and the equivalent damping ratio estimated by Jacobsen’s method. Such linearisation is the basis of Direct Displacement-Based Design (DDBD). Then, the accuracy of the linearisation to assess the peak seismic displacement response is evaluated by numerically testing 5,880 mid- to long-period PT-SKID frames. The results show that the linear equivalence frequently underestimated the peak displacement response, leading to an unconservative design in the DDBD. To eliminate the influence of this error, a correction factor is suggested for the design spectrum used in the DDBD of the PT-SKID frames. Chapter 7 proposes a novel Post-Tensioned Precast Warehouse structure with the Sliding Keys on Inclined Deflecting-cantilevers Device (the PTPW-SKID Structure) following the concept of the PT-SKID frame for industrial buildings. The structure comprises a PT outer frame and a SKID inner frame. The PT outer frame supports the roof and cladding systems; and the SKID inner frame supports the SKID devices and crane system. The design and seismic performance of the PTPW-SKID structure are presented by a case frame located in L'Aquila, Italy. The Direct Displacement-Based Design (DDBD) method is utilised for the seismic design. A 3D numerical model is built in OpenSees. Both quasi-static and seismic dynamic analyses are carried out to investigate its hysteretic behaviour and the seismic response.<br/

Incentives For Poultry Integrators To Contract Bio-Secure Producers And Implication For Government Indemnification Program

These recent events of H1N1 flu outbreak illustrate the potential ramifications of infectious diseases on modern society and how society responds to these threats. This thesis addresses the specific case of avian influenza in U.S. poultry production. By building an expected utility maximization model for integrators contracting with growers of varying bio-secure levels, one can investigate the relationship between the bio-secure choice of the poultry industry and their production performance. The model is empiricized using the Phoon, Quek, and Huang (PQH) simulation technique to conduct numerical analysis. The model selects the optimal percentage of bio-secure farms for the integrators to contract, output price reductions due to disease outbreak, and different probabilities of disease outbreak. Results allow the examination of whether alternative USDA/APHIS indemnification rules can sufficiently influence integrators willingness to improve their bio-security level