Ability of γδ T cells to modulate the Foxp3 T cell response is dependent on adenosine.

Whether γδ T cells inhibit or enhance the Foxp3 T cell response depends upon their activation status. The critical enhancing effector in the supernatant is adenosine. Activated γδ T cells express adenosine receptors at high levels, which enables them to deprive Foxp3+ T cells of adenosine, and to inhibit their expansion. Meanwhile, cell-free supernatants of γδ T cell cultures enhance Foxp3 T cell expansion. Thus, inhibition and enhancement by γδ T cells of Foxp3 T cell response are a reflection of the balance between adenosine production and absorption by γδ T cells. Non-activated γδ T cells produce adenosine but bind little, and thus enhance the Foxp3 T cell response. Activated γδ T cells express high density of adenosine receptors and have a greatly increased ability to bind adenosine. Extracellular adenosine metabolism and expression of adenosine receptor A2ARs by γδ T cells played a major role in the outcome of γδ and Foxp3 T cell interactions. A better understanding of the functional conversion of γδ T cells could lead to γδ T cell-targeted immunotherapies for related diseases

Mapping dusty star formation in and around a cluster at z=0.81 by wide-field imaging with AKARI

We present environmental dependence of dusty star forming activity in and around the cluster RXJ1716.4+6708 at z=0.81 based on wide-field and multi-wavelength observations with Suprime-Cam on the Subaru telescope and IRC onboard the AKARI satellite. Our optical data shows that the optical colour distribution of galaxies starts to dramatically change from blue to red at the medium-density environment such as cluster outskirts, groups and filaments. By combining with infrared data, we find that 15 micron galaxies tend to have optical colours between the red sequence and the blue cloud with a tail into the red sequence. The spatial distribution of the 15 micron galaxies over ~200 arcmin^2 around the cluster reveals that few 15 micron galaxies are detected in the cluster central region. This is probably due to the low star forming activity in the cluster core. However, interestingly, the fraction of 15 micron galaxies in the medium-density environments is as high as in the low-density field, despite the fact that the optical colours start to change in the medium-density environments. Furthermore, we find that 15 micron galaxies which have optically red colours (candidates for dusty red galaxies) and galaxies with high specific star formation rates are also concentrated in the medium-density environment. These results imply that the star forming activity in galaxies in groups and filaments is enhanced due to some environmental effects specific to the medium-density environment, and such a phenomenon is probably directly connected to the truncation of star forming activity in galaxies seen as the dramatic change in optical colours in such environments.Comment: 15 pages, 14 figures, accepted for publication in MNRA

Transiting extrasolar planetary candidates in the Galactic bulge

More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to the reflex motions of their host stars, and more recently through transits of some planets across the face of the host stars. The detection of planets with the shortest known periods, 1.2 to 2.5 days, has mainly resulted from transit surveys which have generally targeted stars more massive than 0.75 M_sun. Here we report the results from a planetary transit search performed in a rich stellar field towards the Galactic bulge. We discovered 16 candidates with orbital periods between 0.4 and 4.2 days, five of which orbit stars of 0.44 to 0.75 M_sun. In two cases, radial-velocity measurements support the planetary nature of the companions. Five candidates have orbital periods below 1.0 day, constituting a new class of ultra-short-period planets (USPPs), which occur only around stars of less than 0.88 M_sun. This indicates that those orbiting very close to more luminous stars might be evaporatively destroyed, or that jovian planets around lower-mass stars might migrate to smaller radii.Comment: To appear in October 5, 2006 issue of Natur

Spacelike Singularities and Hidden Symmetries of Gravity

We review the intimate connection between (super-)gravity close to a spacelike singularity (the "BKL-limit") and the theory of Lorentzian Kac-Moody algebras. We show that in this limit the gravitational theory can be reformulated in terms of billiard motion in a region of hyperbolic space, revealing that the dynamics is completely determined by a (possibly infinite) sequence of reflections, which are elements of a Lorentzian Coxeter group. Such Coxeter groups are the Weyl groups of infinite-dimensional Kac-Moody algebras, suggesting that these algebras yield symmetries of gravitational theories. Our presentation is aimed to be a self-contained and comprehensive treatment of the subject, with all the relevant mathematical background material introduced and explained in detail. We also review attempts at making the infinite-dimensional symmetries manifest, through the construction of a geodesic sigma model based on a Lorentzian Kac-Moody algebra. An explicit example is provided for the case of the hyperbolic algebra E10, which is conjectured to be an underlying symmetry of M-theory. Illustrations of this conjecture are also discussed in the context of cosmological solutions to eleven-dimensional supergravity.Comment: 228 pages. Typos corrected. References added. Subject index added. Published versio

A Peaceman-Rachford Splitting Method for the Protein Side-Chain Positioning Problem

We formulate a doubly nonnegative (DNN) relaxation of the protein side-chain positioning (SCP) problem. We take advantage of the natural splitting of variables that stems from the facial reduction technique in the semidefinite relaxation, and we solve the relaxation using a variation of the Peaceman-Rachford splitting method. Our numerical experiments show that we solve all our instances of the SCP problem to optimality

Kinetic Phenomena in Thin Film Electronic Materials

Contains reports on ten research projects.Semiconductor Research Corporation (Grant 83-01-033)National Science Foundation (Grant DMR 81-19285)U.S. Department of Energy (Contract DE-ACO2-82-ER-13019)National Science Foundation (Grant ECS82-05701)International Business Machines, Inc.Dartmouth UniversityJoint Services Electronics Program (Contract DAAG29-83-K-0003

Comparing serial X-ray crystallography and microcrystal electron diffraction (MicroED) as methods for routine structure determination from small macromolecular crystals.

Innovative new crystallographic methods are facilitating structural studies from ever smaller crystals of biological macromolecules. In particular, serial X-ray crystallography and microcrystal electron diffraction (MicroED) have emerged as useful methods for obtaining structural information from crystals on the nanometre to micrometre scale. Despite the utility of these methods, their implementation can often be difficult, as they present many challenges that are not encountered in traditional macromolecular crystallography experiments. Here, XFEL serial crystallography experiments and MicroED experiments using batch-grown microcrystals of the enzyme cyclophilin A are described. The results provide a roadmap for researchers hoping to design macromolecular microcrystallography experiments, and they highlight the strengths and weaknesses of the two methods. Specifically, we focus on how the different physical conditions imposed by the sample-preparation and delivery methods required for each type of experiment affect the crystal structure of the enzyme

Kinetic Phenomena in Thin Film Electronic Materials

Contains reports on nine research projects.National Science Foundation (Grant ECS85-06565)Semiconductor Research CorporationU.S. Air Force - Office of Scientific Research (Grant AFOSR-85-0154)National Science Foundation (Grant DMR81-19285)Sony International Business Machines, Inc.Dartmouth UniversityJoint Services Electronics Program (Contract DAAG29-83-K-0003)Semiconductor Research Corporatio

Kinetic Phenomena in Thin Film Electronic Materials

Contains reports on twelve research projects.National Science Foundation (Grant ECS 85-06505)U.S. Air Force - Office of Scientific Research (Contract AFOSR-85-0154)Semiconductor Research Corporation (Contract 87-SP-080)National Science Foundation (Grant ECS 85-06565)International Business Machines, Inc.Sony International Business Machines, Inc.National Science Foundation (Grant DMR 84-18718)International Business Machines, Thomas J. Watson Research CenterJoint Services Electronics Program (Contract DAALO3-86-K-0002)National Science Foundation (Grant DMR 85-06030)Charles Stark Draper Laboratory (Contract DL-H-261827)Nippon Telegraph and Telephone, Inc