OPTIMIZING GLYCOLIPIDS FOR THE TREATMENT OF TYPE 1 DIABETES

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease resulting from the destruction of pancreatic islet |3 cells. The non-obese diabetic (NOD) mouse is a model for T1D. a-GalCer activates iNKT cells and reduces incidence of T1D in the NOD mouse. It is a potent iNKT cell agonist whose effects are not specific for T1D. Structural modifications to a-GalCer were made and tested in the NOD mouse in an attempt to optimize glycolipid-mediated protection from T1D. We found that PBS-25 exacerbated T1D whereas PBS-24 protected against T1D. PBS-25 failed to elicit a TH2-bias shift in cytokine secretion, decreased iNKT cell frequency in the pancreatic lymph nodes (PLN), and did not induce tolerogenic DCs. Conversely, PBS-24 caused a Tn2-bias shift in cytokine secretion, reduced islet inflammation while maintaining iNKT cell frequency in the PLN. This structure/function correlation provides insight into the optimization of glycolipids specific for the treatment of T1D

Final report of the EURISOL Design Study (2005-2009) A Design Study for a European Isotope-Separation-On-Line Radioactive Ion Beam Facility

European Commission Contract N°515768 RIDS Published by GANI

Singular Laplacian Growth

The general equations of motion for two dimensional Laplacian growth are derived using the conformal mapping method. In the singular case, all singularities of the conformal map are on the unit circle, and the map is a degenerate Schwarz-Christoffel map. The equations of motion describe the motions of these singularities. Despite the typical fractal-like outcomes of Laplacian growth processes, the equations of motion are shown to be not particularly sensitive to initial conditions. It is argued that the sensitivity of this system derives from a novel cause, the non-uniqueness of solutions to the differential system. By a mechanism of singularity creation, every solution can become more complex, even in the absence of noise, without violating the growth law. These processes are permitted, but are not required, meaning the equation of motion does not determine the motion, even in the small.Comment: 8 pages, Latex, 4 figures, Submitted to Phys. Rev.

Non-linear conformally invariant generalization of the Poisson equation to D>2 dimensions

I propound a non-linear generalization of the Poisson equation describing a "medium" in D dimensions with a "dielectric constant" proportional to the field strength to the power D-2. It is the only conformally invariant scalar theory that is second order, and in which the scalar $phi$ couples to the sources $\rho$ via a $\phi\rho$ contact term. The symmetry is used to generate solutions for the field for some non-trivial configurations (e.g. for two oppositely charged points). Systems comprising N point charges afford further application of the symmetry. For these I derive e.g. exact expressions for the following quantities: the general two-point-charge force; the energy function and the forces in any three-body configuration with zero total charge; the few-body force for some special configurations; the virial theorem for an arbitrary, bound, many-particle system relating the time-average kinetic energy to the particle charges. Possible connections with an underlying conformal quantum field theory are mentioned.Comment: Revtex, 16 pages. To be published in Phys. Rev.

Stresses in isostatic granular systems and emergence of force chains

Progress is reported on several questions that bedevil understanding of granular systems: (i) are the stress equations elliptic, parabolic or hyperbolic? (ii) how can the often-observed force chains be predicted from a first-principles continuous theory? (iii) How to relate insight from isostatic systems to general packings? Explicit equations are derived for the stress components in two dimensions including the dependence on the local structure. The equations are shown to be hyperbolic and their general solutions, as well as the Green function, are found. It is shown that the solutions give rise to force chains and the explicit dependence of the force chains trajectories and magnitudes on the local geometry is predicted. Direct experimental tests of the predictions are proposed. Finally, a framework is proposed to relate the analysis to non-isostatic and more realistic granular assemblies.Comment: 4 pages, 2 figures, Corrected typos and clkearer text, submitted to Phys. Rev. Let

Nonequilibrium brittle fracture propagation: Steady state, oscillations and intermittency

A minimal model is constructed for two-dimensional fracture propagation. The heterogeneous process zone is presumed to suppress stress relaxation rate, leading to non-quasistatic behavior. Using the Yoffe solution, I construct and solve a dynamical equation for the tip stress. I discuss a generic tip velocity response to local stress and find that noise-free propagation is either at steady state or oscillatory, depending only on one material parameter. Noise gives rise to intermittency and quasi-periodicity. The theory explains the velocity oscillations and the complicated behavior seen in polymeric and amorphous brittle materials. I suggest experimental verifications and new connections between velocity measurements and material properties.Comment: To appear in Phys. Rev. Lett., 6 pages, self-contained TeX file, 3 postscript figures upon request from author at [email protected] or [email protected], http://cnls-www.lanl.gov/homepages/rafi/rafindex.htm

Emotional Eating, Self-Esteem, and Resilience in Young Adults

Research suggests that unhealthy eating behaviors occur for various reasons, most notably by perceiving external cues of food, but also from excessive stress. Research also suggests that people cope by either overeating or undereating in response to stress. There are two possible contributing factors to the presence of emotional undereating and emotional overeating: resilience to stress and self-esteem. The purpose of this study was to examine whether self-esteem and resilience limit emotional undereating (EUE) or emotional over-eating (EOE). Here [GU1] we show that resilience has more of an impact on both EOE and EUE than self-esteem. In a sample of 183 adults, correlational analyses found that self-esteem and resilience are inversely associated with undereating but not overeating. In exploring these associations further, a multiple regression analysis was conducted by entering both resilience and self-esteem as predictors of undereating. It was found that resilience is the primary buffer in limiting undereating. In other words, those with resilience tend to exhibit healthier eating habits beyond that of one\u27s self-esteem. This is in opposition to the commonly held belief that self-esteem is the main contributing factor to unhealthy eating patterns. It is reasonable to suggest that resilience, defined as an ability to adapt to stress, serves as a mechanism to limit unhealthy eating behaviors when stressed. Self-esteem, on the other hand, does not seem to serve this unique purpose. These results are important in understanding and preventing unhealthy emotional eating behaviors. In particular, building resilience instead of self-esteem, might help curb unhealthy eating

Nuclear break-up of 11Be

The break-up of 11Be was studied at 41AMeV using a secondary beam of 11Be from the GANIL facility on a 48Ti target by measuring correlations between the 10Be core, the emitted neutrons and gamma rays. The nuclear break-up leading to the emission of a neutron at large angle in the laboratory frame is identified with the towing mode through its characteristic n-fragment correlation. The experimental spectra are compared with a model where the time dependent Schrodinger equation (TDSE) is solved for the neutron initially in the 11 Be. A good agreement is found between experiment and theory for the shapes of neutron experimental energies and angular distributions. The spectroscopic factor of the 2s orbital is tentatively extracted to be 0.46+-0.15. The neutron emission from the 1p and 1d orbitals is also studied

Search for low lying dipole strength in the neutron rich nucleus 26^{26}Ne

Coulomb excitation of the exotic neutron-rich nucleus $^{26}$Ne on a $^{nat}$Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. Data were also taken on an $^{nat}$Al target to estimate the nuclear contribution. The radioactive beam was produced by fragmentation of a 95 A.MeV $^{40}$Ar beam delivered by the RIKEN Research Facility. The set-up included a NaI gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the $^{25}$Ne+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV. The reconstructed $^{26}$Ne angular distribution confirms its E1 nature. A reduced dipole transition probability of B(E1)=0.49$\pm$0.16 $e^2fm^2$ is deduced. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is obtained. The results are discussed in terms of a pygmy resonance centered around 9 MeV