607 research outputs found
Combinations of idelalisib with rituximab and/or bendamustine in patients with recurrent indolent non-Hodgkin lymphoma
Key Points
Combining phosphatidylinositol-3-kinase δ inhibition with rituximab, bendamustine, or both is feasible and active in relapsed iNHL. The safety of novel combinations should be proven in phase 3 trials before adoption in clinical practice.</jats:p
An Approach to Evaluation of the Effect of Bioremediation on Biological Activity of Environmental Contaminants: Dechlorination of Polychlorinated Biphenyls
The effectiveness of bioremediation efforts is assessed traditionally from the loss of the chemical of interest. In some cases, analytical techniques are coupled with evaluation of toxicity to organisms representative of those found in the affected environment or surrogate organisms. Little is known, however, about the effect of remediation of environmental chemicals on potential toxicity to mammalian organisms. We discuss both an approach that employs mammalian cell system bioassays and the criteria for selection of the assays. This approach has been used to evaluate the biological response to mixtures of polychlorinated biphenyls (PCBs) before and after remediation by reductive dechlorination. The dechlorination process used results in accumulation of congeners substituted in only the ortho and para positions and containing fewer chlorines than the starting mixtures. Evaluation of the dechlorinated mixture reveals a loss of biological activity that could be ascribed to coplanar PCBs not containing chlorine in the ortho positions. Conversely, biological activity associated with ortho-substituted PCB congeners is unaffected or increased by remediation. Thus, the results of the bioassays are consistent with the remediation-induced change in the profile of PCB congeners and the known mechanisms of action of PCBs. The results emphasize a need for evaluation of the products of remediation for biological activity in mammalian systems. Furthermore, the approach outlined demonstrates the potential to assess the impact of remediation on a range of biological activities in mammalian cells and thus to estimate positive and negative effects of remediation strategies on toxicity. Future needs in this area of research include assays to evaluate biological effects under conditions of exposure that mimic those found in the environment and models to extrapolate effects to assess risk to people and wildlife
Casimir micro-sphere diclusters and three-body effects in fluids
Our previous article [Phys. Rev. Lett. 104, 060401 (2010)] predicted that
Casimir forces induced by the material-dispersion properties of certain
dielectrics can give rise to stable configurations of objects. This phenomenon
was illustrated via a dicluster configuration of non-touching objects
consisting of two spheres immersed in a fluid and suspended against gravity
above a plate. Here, we examine these predictions from the perspective of a
practical experiment and consider the influence of non-additive, three-body,
and nonzero-temperature effects on the stability of the two spheres. We
conclude that the presence of Brownian motion reduces the set of experimentally
realizable silicon/teflon spherical diclusters to those consisting of layered
micro-spheres, such as the hollow- core (spherical shells) considered here.Comment: 11 pages, 9 figure
The equation of state for two flavor QCD at N_t=6
We calculate the two flavor equation of state for QCD on lattices with
lattice spacing a=(6T)^{-1} and find that cutoff effects are substantially
reduced compared to an earlier study using a=(4T)^{-1}. However, it is likely
that significant cutoff effects remain. We fit the lattice data to expected
forms of the free energy density for a second order phase transition at
zero-quark-mass, which allows us to extrapolate the equation of state to m_q=0
and to extract the speed of sound. We find that the equation of state depends
weakly on the quark mass for small quark mass.Comment: 24 pages, latex, 11 postscipt figure
Tracking Changes in Bioavailable Fe Within High-Nitrate Low-Chlorophyll Oceanic Waters: A First Estimate Using a Heterotrophic Bacterial Bioreporter
It is conventional knowledge that heterotrophic bacteria play a key role in the biogeochemical cycling of oceanic carbon. However, only recently has their role in marine iron ( Fe) biogeochemical cycles been examined. Research during this past decade has demonstrated an inextricable link between Fe chemistry and the biota, as \u3e99% of Fe in marine systems is complexed to organic chelates of unknown but obviously biotic origin. Here we present a novel approach to assess and compare Fe bioavailability in low Fe HNLC waters using a bioluminescent bacterial reporter that quantitatively responds to the concentration of bioavailable Fe by producing light. Originally tested in freshwater environments, this study presents the first characterization of this halotolerant reporter organism in a defined seawater medium and then subsequently in marine surface waters. Laboratory characterizations demonstrate that this reporter displays a dose-dependent response to Fe availability in our defined marine medium. Field tests were performed during the 10-day mesoscale FeCycle experiment ( February 2003) in the Pacific sub-Antarctic high-nitrate low-chlorophyll region. Data from both biogeochemical measures and bioreporter assays are provided which describe how the bioreporter detected changes in Fe bioavailability that occurred during a natural shift in ambient dissolved Fe concentrations (similar to 40 pM). Our data explore the use of heterotrophic bioluminescent reporters as a comparable tool for marine ecosystems and demonstrate the potential utility of this tool in elucidating the relationship between Fe bioavailability and Fe chemistry in complex marine systems
The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 With a Large Dense Core
Doppler measurements from Subaru and Keck have revealed radial velocity
variations in the V=8.15, G0IV star HD 149026 consistent with a Saturn-Mass
planet in a 2.8766 day orbit. Photometric observations at Fairborn Observatory
have detected three complete transit events with depths of 0.003 mag at the
predicted times of conjunction. HD 149026 is now the second brightest star with
a transiting extrasolar planet. The mass of the star, based on interpolation of
stellar evolutionary models, is 1.3 +/- 0.1 solar masses; together with the
Doppler amplitude, K=43.3 m s^-1, we derive a planet mass Msin(i)=0.36 Mjup,
and orbital radius of 0.042 AU. HD 149026 is chromospherically inactive and
metal-rich with spectroscopically derived [Fe/H]=+0.36, Teff=6147 K, log g=4.26
and vsin(i)=6.0 km s^-1. Based on Teff and the stellar luminosity of 2.72 Lsun,
we derive a stellar radius of 1.45 Rsun. Modeling of the three photometric
transits provides an orbital inclination of 85.3 +/- 1.0 degrees and (including
the uncertainty in the stellar radius) a planet radius of 0.725 +/- 0.05 Rjup.
Models for this planet mass and radius suggest the presence of a ~67 Mearth
core composed of elements heavier than hydrogen and helium. This substantial
planet core would be difficult to construct by gravitational instability.Comment: 25 pages, 5 figures, accepted by the Astrophysical Journa
Virtual photons in imaginary time: Computing exact Casimir forces via standard numerical-electromagnetism techniques
We describe a numerical method to compute Casimir forces in arbitrary
geometries, for arbitrary dielectric and metallic materials, with arbitrary
accuracy (given sufficient computational resources). Our approach, based on
well-established integration of the mean stress tensor evaluated via the
fluctuation-dissipation theorem, is designed to directly exploit fast methods
developed for classical computational electromagnetism, since it only involves
repeated evaluation of the Green's function for imaginary frequencies
(equivalently, real frequencies in imaginary time). We develop the approach by
systematically examining various formulations of Casimir forces from the
previous decades and evaluating them according to their suitability for
numerical computation. We illustrate our approach with a simple
finite-difference frequency-domain implementation, test it for known geometries
such as a cylinder and a plate, and apply it to new geometries. In particular,
we show that a piston-like geometry of two squares sliding between metal walls,
in both two and three dimensions with both perfect and realistic metallic
materials, exhibits a surprising non-monotonic ``lateral'' force from the
walls.Comment: Published in Physical Review A, vol. 76, page 032106 (2007
Quenched hadron spectroscopy with improved staggered quark action
We investigate light hadron spectroscopy with an improved quenched staggered
quark action. We compare the results obtained with an improved gauge plus an
improved quark action, an improved gauge plus standard quark action, and the
standard gauge plus standard quark action. Most of the improvement in the
spectroscopy results is due to the improved gauge sector. However, the improved
quark action substantially reduces violations of Lorentz invariance, as
evidenced by the meson dispersion relations.Comment: New references adde
The discovery of potent, selective, and reversible inhibitors of the house dust mite peptidase allergen Der p 1: an innovative approach to the treatment of allergic asthma.
Blocking the bioactivity of allergens is conceptually attractive as a small-molecule therapy for allergic diseases but has not been attempted previously. Group 1 allergens of house dust mites (HDM) are meaningful targets in this quest because they are globally prevalent and clinically important triggers of allergic asthma. Group 1 HDM allergens are cysteine peptidases whose proteolytic activity triggers essential steps in the allergy cascade. Using the HDM allergen Der p 1 as an archetype for structure-based drug discovery, we have identified a series of novel, reversible inhibitors. Potency and selectivity were manipulated by optimizing drug interactions with enzyme binding pockets, while variation of terminal groups conferred the physicochemical and pharmacokinetic attributes required for inhaled delivery. Studies in animals challenged with the gamut of HDM allergens showed an attenuation of allergic responses by targeting just a single component, namely, Der p 1. Our findings suggest that these inhibitors may be used as novel therapies for allergic asthma
Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study - Part 2: Philippine receptor observations of fine-scale aerosol behavior
Abstract. The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds
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