Ab initio determination of an extended Heisenberg Hamiltonian in CuO2 layers

Accurate ab initio calculations on embedded Cu_4O_{12} square clusters, fragments of the La_2CuO_4 lattice, confirm a value of the nearest neighbor antiferromagnetic coupling (J=124 meV) previously obtained from ab initio calculations on bicentric clusters and in good agreement with experiment. These calculations predict non negligible antiferromagnetic second-neighbor interaction (J'=6.5 meV) and four-spin cyclic exchange (K=14 meV), which may affect the thermodynamic and spectroscopic properties of these materials. The dependence of the magnetic coupling on local lattice distortions has also been investigated. Among them the best candidate to induce a spin-phonon effect seems to be the movement of the Cu atoms, changing the Cu-Cu distance, for which the variation of the nearest neighbor magnetic coupling with the Cu-O distance is {\Delta J}/{\Delta d_{Cu-O}}\sim 1700 cm^{-1} A^{-1}.Comment: 11 pages, 5 figures, submitted to Phys. Rev.

The symmetry of mobility laws for viscous flow along arbitrarily patterned surfaces

Generalizations of the no-slip boundary condition to allow for slip at a patterned fluid-solid boundary introduce a surface mobility tensor, which relates the shear traction vector tangent to the mean surface to an apparent surface velocity vector. For steady, low-Reynolds-number fluid motions over planar surfaces perturbed by arbitrary periodic height and Navier slip fluctuations, we prove that the resulting mobility tensor is always symmetric, which had previously been conjectured. We describe generalizations of the results to three other families of geometries, which typically have unsteady flow.National Science Foundation (U.S.) (NSF MSPRF program)National Institutes of Health (U.S.) (NSF Grant No. CBET-0961081

c ○ 1998 Kluwer Academic Publishers. Manufactured in The Netherlands. Safe-for-Space Threads in Standard ML ∗

Abstract. Threads can easily be implemented using first-class continuations, but the straightforward approaches for doing so lead to space leaks, especially in a language with exceptions like Standard ML. We show how these space leaks arise and give a new implementation for threads that is safe for space. Keywords: continuations, coroutines, Standard ML, space safety, thread

Enhancing the Evidence for Behavioral Counseling A Perspective From the Society of Behavioral Medicine

U.S. Preventive Services Task Force (USPSTF) clinical guidelines at present rarely assign the highest grade recommendation to behavioral counseling interventions for chronic disease prevention or risk reduction because of concerns about the certainty and quality of the evidence base. As a result, the broad integration of behavioral counseling interventions in primary care remains elusive. Thus, there is an urgent need for novel perspectives on how to generate the highest-quality and -certainty evidence for primary care–focused behavioral counseling interventions. As members of the Society of Behavioral Medicine (SBM)—a multidisciplinary scientific organization committed to improving population health through behavior change—we review the USPSTF mandate and current recommendations for behavioral counseling interventions and provide a perspective for the future that calls for concerted and coordinated efforts among SBM, USPSTF, and other organizations invested in the rapid and wider uptake of beneficial, feasible, and referable primary care–focused behavioral counseling interventions. This perspective highlights five areas for further development, including (1) behavioral counseling–focused practice-based research networks; (2) promotion of USPSTF evidence standards and the increased use of pragmatic RCT design; (3) quality control and improvement procedures for behavioral counseling training; (4) systematic research on effective primary care–based collaborative care models; and (5) methodologic innovations that capitalize on disruptive technologies and healthcare transformation. Collective efforts to improve the health of all Americans in the 21st century and beyond must ensure that effective, feasible, and referable behavioral counseling interventions are embedded in modern primary care practice

Implementing a pilot leadership course for internal medicine residents: design considerations, participant impressions, and lessons learned

Background: Effective clinical leadership is associated with better patient care. We implemented and evaluated a pilot clinical leadership course for second year internal medicine residents at a large United States Academic Medical Center that is part of a multi-hospital health system. Methods: The course met weekly for two to three hours during July, 2013. Sessions included large group discussions and small group reflection meetings. Topics included leadership styles, emotional intelligence, and leading clinical teams. Course materials were designed internally and featured “business school style” case studies about everyday clinical medicine which explore how leadership skills impact care delivery. Participants evaluated the course’s impact and quality using a post-course survey. Questions were structured in five point likert scale and free text format. Likert scale responses were converted to a 1-5 scale (1 = strongly disagree; 3 = neither agree nor disagree; 5 = strongly agree), and means were compared to the value 3 using one-way T-tests. Responses to free text questions were analyzed using the constant comparative method. Results: All sixteen pilot course participants completed the survey. Participants overwhelmingly agreed that the course provided content and skills relevant to their clinical responsibilities and leadership roles. Most participants also acknowledged that taking the course improved their understanding of their strengths and weaknesses as leaders, different leadership styles, and how to manage interpersonal conflict on clinical teams. 88% also reported that the course increased their interest in pursuing additional leadership training. Conclusions: A clinical leadership course for internal medicine residents designed by colleagues, and utilizing case studies about clinical medicine, resulted in significant self-reported improvements in clinical leadership competencies. Electronic supplementary material The online version of this article (doi:10.1186/s12909-014-0257-2) contains supplementary material, which is available to authorized users

The Heliopause Electrostatic Rapid Transit System (HERTS) - Design, Trades, and Analyses Performed in a Two Year NASA Investigation of Electric Sail Propulsion Systems

Personnel from NASA's MSFC have been investigating the feasibility of an advanced propulsion system known as the Electric Sail (E-Sail) for future scientific exploration missions. This team initially won a NASA Space Technology Mission Directorate (STMD) Phase I NASA Innovative Advanced Concept (NIAC) award and then a two-year follow-on Phase II NIAC award in October 2015. This paper documents the findings from this three-year investigation. An Electric sail, a propellant-less propulsion system, uses solar wind ions to rapidly travel either to deep space or the inner solar system. Scientific spacecraft could reach Pluto in ~5 years, or the boundary of the solar system in ten to twelve years compared to the thirty-five plus years the Voyager spacecraft took. The team's recent focuses have been: 1) Developing a Particle in Cell (PIC) numeric engineering model from MSFC's experimental data on the interaction between simulated solar wind and a charged bare wire that can be applied to a variety of missions, 2) Determining what missions could benefit from this revolutionary propulsion system, 3) Conceptualizing spacecraft designs for various tasks: to reach the solar system's edge, to orbit the sun as Heliophysics sentinels, or to examine a multitude of asteroids

Combustion-derived nanoparticles: A review of their toxicology following inhalation exposure

This review considers the molecular toxicology of combustion-derived nanoparticles (CDNP) following inhalation exposure. CDNP originate from a number of sources and in this review we consider diesel soot, welding fume, carbon black and coal fly ash. A substantial literature demonstrates that these pose a hazard to the lungs through their potential to cause oxidative stress, inflammation and cancer; they also have the potential to redistribute to other organs following pulmonary deposition. These different CDNP show considerable heterogeneity in composition and solubility, meaning that oxidative stress may originate from different components depending on the particle under consideration. Key CDNP-associated properties of large surface area and the presence of metals and organics all have the potential to produce oxidative stress. CDNP may also exert genotoxic effects, depending on their composition. CDNP and their components also have the potential to translocate to the brain and also the blood, and thereby reach other targets such as the cardiovascular system, spleen and liver. CDNP therefore can be seen as a group of particulate toxins unified by a common mechanism of injury and properties of translocation which have the potential to mediate a range of adverse effects in the lungs and other organs and warrant further research

The potential risks of nanomaterials: a review carried out for ECETOC

During the last few years, research on toxicologically relevant properties of engineered nanoparticles has increased tremendously. A number of international research projects and additional activities are ongoing in the EU and the US, nourishing the expectation that more relevant technical and toxicological data will be published. Their widespread use allows for potential exposure to engineered nanoparticles during the whole lifecycle of a variety of products. When looking at possible exposure routes for manufactured Nanoparticles, inhalation, dermal and oral exposure are the most obvious, depending on the type of product in which Nanoparticles are used. This review shows that (1) Nanoparticles can deposit in the respiratory tract after inhalation. For a number of nanoparticles, oxidative stress-related inflammatory reactions have been observed. Tumour-related effects have only been observed in rats, and might be related to overload conditions. There are also a few reports that indicate uptake of nanoparticles in the brain via the olfactory epithelium. Nanoparticle translocation into the systemic circulation may occur after inhalation but conflicting evidence is present on the extent of translocation. These findings urge the need for additional studies to further elucidate these findings and to characterize the physiological impact. (2) There is currently little evidence from skin penetration studies that dermal applications of metal oxide nanoparticles used in sunscreens lead to systemic exposure. However, the question has been raised whether the usual testing with healthy, intact skin will be sufficient. (3) Uptake of nanoparticles in the gastrointestinal tract after oral uptake is a known phenomenon, of which use is intentionally made in the design of food and pharmacological components. Finally, this review indicates that only few specific nanoparticles have been investigated in a limited number of test systems and extrapolation of this data to other materials is not possible. Air pollution studies have generated indirect evidence for the role of combustion derived nanoparticles (CDNP) in driving adverse health effects in susceptible groups. Experimental studies with some bulk nanoparticles (carbon black, titanium dioxide, iron oxides) that have been used for decades suggest various adverse effects. However, engineered nanomaterials with new chemical and physical properties are being produced constantly and the toxicity of these is unknown. Therefore, despite the existing database on nanoparticles, no blanket statements about human toxicity can be given at this time. In addition, limited ecotoxicological data for nanomaterials precludes a systematic assessment of the impact of Nanoparticles on ecosystems

Efficacy of Simple Short-Term in Vitro Assays for Predicting the Potential of Metal Oxide Nanoparticles to Cause Pulmonary Inflammation

Background: There has been concern regarding risks from inhalation exposure to nanoparticles (NPs). The large number of particles requiring testing means that alternative approaches to animal testing are needed. Objectives: We set out to determine whether short-term in vitro assays that assess intrinsic oxidative stress potential and membrane-damaging potency of a panel of metal oxide NPs can be used to predict their inflammogenic potency. Methods: For a panel of metal oxide NPs, we investigated intrinsic free radical generation, oxidative activity in an extracellular environment, cytotoxicity to lung epithelial cells, hemolysis, and inflammation potency in rat lungs. All exposures were carried out at equal surface area doses. Results: Only nickel oxide (NiO) and alumina 2 caused significant lung inflammation when instilled into rat lungs at equal surface area, suggesting that these two had extra surface reactivity. We observed significant free radical generation with 4 of 13 metal oxides, only one of which was inflammogenic. Only 3 of 13 were significantly hemolytic, two of which were inflammogenic. Conclusions: Potency in generating free radicals in vitro did not predict inflammation, whereas alumina 2 had no free radical activity but was inflammogenic. The hemolysis assay was correct in predicting the proinflammatory potential of 12 of 13 of the particles examined. Using a battery of simple in vitro tests, it is possible to predict the inflammogenicity of metal oxide NPs, although some false-positive results are likely. More research using a larger panel is needed to confirm the efficacy and generality of this approach for metal oxide NPs

Carbon black nanoparticles induce type II epithelial cells to release chemotaxins for alveolar macrophages.

Background - Alveolar macrophages are a key cell in dealing with particles deposited in the lungs and in determining the subsequent response to that particle exposure. Nanoparticles are considered a potential threat to the lungs and the mechanism of pulmonary response to nanoparticles is currently under intense scrutiny. The type II alveolar epithelial cell has previously been shown to release chemoattractants which can recruit alveolar macrophages to sites of particle deposition. The aim of this study was to assess the responses of a type II epithelial cell line (L-2) to both fine and nanoparticle exposure in terms of secretion of chemotactic substances capable of inducing macrophage migration.ResultsExposure of type II cells to carbon black nanoparticles resulted in significant release of macrophage chemoattractant compared to the negative control and to other dusts tested (fine carbon black and TiO2 and nanoparticle TiO2) as measured by macrophage migration towards type II cell conditioned medium. SDS-PAGE analysis of the conditioned medium from particle treated type II cells revealed that a higher number of protein bands were present in the conditioned medium obtained from type II cells treated with nanoparticle carbon black compared to other dusts tested. Size-fractionation of the chemotaxin-rich supernatant determined that the chemoattractants released from the epithelial cells were between 5 and 30 kDa in size.ConclusionThe highly toxic nature and reactive surface chemistry of the carbon black nanoparticles has very likely induced the type II cell line to release pro-inflammatory mediators that can potentially induce migration of macrophages. This could aid in the rapid recruitment of inflammatory cells to sites of particle deposition and the subsequent removal of the particles by phagocytic cells such as macrophages and neutrophils. Future studies in this area could focus on the exact identity of the substance(s) released by the type II cells in response to particle exposure