Laser plasma diagnostics of dense plasmas

The authors describe several experiments on Nova that use laser-produced plasmas to generate x-rays capable of backlighting dense, cold plasmas (p {approximately} 1--3 gm/cm{sup 3}, kT {approximately} 5--10 eV, and areal density {rho}{ell}{approximately} 0.01--0.05 g/cm{sup 2}). The x-rays used vary over a wide range of h{nu}, from 80 eV (X-ray laser) to 9 keV. This allows probing of plasmas relevant to many hydrodynamic experiments. Typical diagnostics are 100 ps pinhole framing cameras for a long pulse backlighter and a time-integrated CCD camera for a short pulse backlighter

Targeting OLFML3 in colorectal cancer suppresses tumor growth and angiogenesis, and increases the efficacy of anti-PD1 based immunotherapy

The role of the proangiogenic factor olfactomedin-like 3 (OLFML3) in cancer is unclear. To characterize OLFML3 expression in human cancer and its role during tumor development, we undertook tissue expression studies, gene expression analyses of patient tumor samples, in vivo studies in mouse cancer models, and in vitro coculture experiments. OLFML3 was expressed at high levels, mainly in blood vessels, in multiple human cancers. We focused on colorectal cancer (CRC), as elevated expression of OLFML3 mRNA correlated with shorter relapse-free survival, higher tumor grade, and angiogenic microsatellite stable consensus molecular subtype 4 (CMS4). Treatment of multiple in vivo tumor models with OLFML3-blocking antibodies and deletion of the Olfml3 gene from mice decreased lymphangiogenesis, pericyte coverage, and tumor growth. Antibody-mediated blockade of OLFML3 and deletion of host Olfml3 decreased the recruitment of tumor-promoting tumor-associated macrophages and increased infiltration of the tumor microenvironment by NKT cells. Importantly, targeting OLFML3 increased the antitumor efficacy of anti-PD-1 checkpoint inhibitor therapy. Taken together, the results demonstrate that OLFML3 is a promising candidate therapeutic target for CRC. </p

Effects of Hemispheric Circulation on Uranian Atmospheric Dynamics and Methane Depletion

The solar system is filled with meteorological phenomena. For example, geophysical vortices range from hurricanes to the Great Red Spot on Jupiter to the Dark Spots of Uranus and Neptune. These Ice Giant vortices have exhibited unusual dynamical behaviors, such as the shape oscillations and meridional drift of the Great Dark Spot, discovered and observed in 1989 by Voyager II. On the other hand, the Uranian Dark Spot exhibited little to no drift over a similar stretch of observation when it appeared shortly before the spring equinox on Uranus in 2006. Another phenomenon is regions of persistent clouds, common in the banding patterns of the gas giants. The bright companion of the Great Dark Spot is a different type of persistent cloud, arising orographically as the vortex moved through the atmosphere. The Uranian Dark Spot may also have had a similar, although intermittent, cloud companion. Another notable long-lived cloud feature called S34 or the Berg in the southern hemisphere of Uranus, which drifted equatorward covering approximately 30 degrees in latitude over the course of a few years as equinox approached, having previously spent several years in the vicinity of 34 degrees south latitude. While this motion resembles in some ways that of the Great Dark Spot and its Bright Companion, there was no visible vortex associated with the Berg\u27s cloud. A proposed cause of this unexpected drift is the development of a strong meridional, Hadley-cell circulation that caused the cloud (and a possible unseen companion vortex) to drift equatorward. This same circulation may account for observations that showed upper tropospheric methane gas (a primary cloud constituent on Uranus) in the southern hemisphere was preferentially accumulating near the equator while depleting near the south pole. This paper presents the first efforts to examine these phenomena by numerically modeling a full Uranian atmosphere. These simulations are designed to examine these changes in the Uranian atmosphere, probably related to the extreme seasonal change of this planet. While this research will improve our understanding of the Uranian atmosphere and the design of future missions to this system, it will also assist in understanding the similar dynamics on the other Ice Giant planet Neptune, and potentially with similar phenomena in Earth\u27s atmosphere like hurricane drift. © 2012 by by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc

Non-thermal effects in a hot dense plasma

A hollow gas shell Z-pinch device is described, and some initial observations are shown to lead to the conclusion that there is an energetic electron beam produced along the axis of the collapsing gas shell. An experiment is summarized that directly measured some of the characteristics of this runaway electron beam. Finally, the results of an experiment which observed a new affect are presented along with a model that uses a runaway electron beam to explain this new effect. 9 refs., 17 figs

THE SANDIA X-RAY LASER PROGRAM

Le laser au rayon X en train d'être développé aux Laboratoires Sandia utilise un rayonnement keV intense, produit par la compression cylindrique ("Z-pinch") d'une bouffée de gaz, pour obtenir les ions de la série isoélectronique F par la photoionisation des ions Ne. Les populations des niveaux de la configuration (2p)5(3p) et de la configuration (2p)5(3s) sont inverties par des processus de recombinaison des ions. Une enveloppe annulaire de stagnation maintient la séparation entre la source du rayonnement et le plasma étant lasé. Une couche mince d'aluminium ou sodium sert pour changer la longueur d'onde du rayonnement. La méthode pour arriver aux dimensions et à la densité du laser au rayon X est décrite.The Sandia X-ray Laser Program is based on the use of intense keV radiation produced by gas puff, Z-pinch implosions to photoionize Ne-like ions to F-like ions. A 3p-3s population inversion is generated via recombination processes. An annular stagnation shell is used to separate the imploding pump source from the lasant. We are also developing a converter technology for examining the Na-Ne line matching scheme. Design considerations and some computational results are presented

Z-PINCH IMPLOSION DRIVEN X-RAY LASER RESEARCH

In experiments performed during the past two years on Proto II (a 10-TW pulsed-power accelerator), we imploded annular plasmas onto thin-walled annular x-ray laser targets in order to create a radiation pump source for x-ray laser physics studies. This Z-pinch must be axially uniform and must efficiently produce the pump radiation without destroying the laser medium on the cylindrical axis of symmetry. To characterize the pump source x-rays and lasant conditions, we regularly field a large number of x-ray diagnostics. In recent experiments, we produced over 15 kJ of ≥1-keV pump radiation with an imploding neon gas-puff load. We are considering both recombination and resonance-pumped x-ray laser schemes