3,316 research outputs found
Tuning the contact conductance of anchoring groups in single molecule junctions by molecular design
A tetraphenylmethane tripod functionalized with three thiol moieties in the para position can serve as a supporting platform for functional molecular electronic elements. A combined experimental scanning tunneling microscopy break junction technique with theoretical approaches based on density functional theory and non-equilibrium Green`s function formalism was used for detailed charge transport analysis to find configurations, geometries and charge transport pathways in the molecular junctions of single molecule oligo-
Photolytic and Reductive Activations of 2âArsaethynolate in a UraniumâTriamidoamine Complex: Decarbonylative Arsenic GroupâTransfer Reactions and Trapping of a Highly Bent and Reduced Form
Little is known about the chemistry of the 2-arsaethynolate anion, but to date it has exclusively undergone fragmentation reactions when reduced. Herein, we report the synthesis of [U(Tren(TIPS))(OCAs)] (2, Tren(TIPS)=N(CH(2)CH(2)NSiiPr(3))(3)), which is the first isolable actinide-2-arsaethynolate linkage. UV-photolysis of 2 results in decarbonylation, but the putative [U(Tren(TIPS))(As)] product was not isolated and instead only [{U(Tren(TIPS))}(2)(mu-eta(2):eta(2)-As2H2)] (3) was formed. In contrast, reduction of 2 with [U(Tren(TIPS))] gave the mixed-valence arsenido [{U(Tren(TIPS))}(2)(mu-As)] (4) in very low yield. Complex 4 is unstable which precluded full characterisation, but these photolytic and reductive reactions testify to the tendency of 2-arsaethynolate to fragment with CO release and As transfer. However, addition of 2 to an electride mixture of potassium-graphite and 2,2,2-cryptand gives [{U(Tren(TIPS))}(2){mu-eta(2)(OAs):eta(2)(CAs)-OCAs}][K(2,2,2-cryptand)] (5). The coordination mode of the trapped 2-arsaethynolate in 5 is unique, and derives from a new highly reduced and bent form of this ligand with the most acute O-C-As angle in any complex to date (O-C-As angle approximate to 128 degrees). The trapping rather than fragmentation of this highly reduced O-C-As unit is unprecedented, and quantum chemical calculations reveal that reduction confers donor-acceptor character to the O-C-As unit
New insights into the performance of human whole-exome capture platforms
Whole exome sequencing (WES) is increasingly used in research and diagnostics. WES users expect coverage of the entire coding region of known genes as well as sufficient read depth for the covered regions. It is, however, unknown which recent WES platform is most suitable to meet these expectations. We present insights into the performance of the most recent standard exome enrichment platforms from Agilent, NimbleGen and Illumina applied to six different DNA samples by two sequencing vendors per platform. Our results suggest that both Agilent and NimbleGen overall perform better than Illumina and that the high enrichment performance of Agilent is stable among samples and between vendors, whereas NimbleGen is only able to achieve vendor- and sample-specific best exome coverage. Moreover, the recent Agilent platform overall captures more coding exons with sufficient read depth than NimbleGen and Illumina. Due to considerable gaps in effective exome coverage, however, the three platforms cannot capture all known coding exons alone or in combination, requiring improvement. Our data emphasize the importance of evaluation of updated platform versions and suggest that enrichment-free whole genome sequencing can overcome the limitations of WES in sufficiently covering coding exons, especially GC-rich regions, and in characterizing structural variant
Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS
Forward calorimetry in the PHOBOS detector has been used to study charged
hadron production in d+Au, p+Au and n+Au collisions at sqrt(s_nn) = 200 GeV.
The forward proton calorimeter detectors are described and a procedure for
determining collision centrality with these detectors is detailed. The
deposition of energy by deuteron spectator nucleons in the forward calorimeters
is used to identify p+Au and n+Au collisions in the data. A weighted
combination of the yield of p+Au and n+Au is constructed to build a reference
for Au+Au collisions that better matches the isospin composition of the gold
nucleus. The p_T and centrality dependence of the yield of this improved
reference system is found to match that of d+Au. The shape of the charged
particle transverse momentum distribution is observed to extrapolate smoothly
from pbar+p to central d+Au as a function of the charged particle
pseudorapidity density. The asymmetry of positively- and negatively-charged
hadron production in p+Au is compared to that of n+Au. No significant asymmetry
is observed at mid-rapidity. These studies augment recent results from
experiments at the LHC and RHIC facilities to give a more complete description
of particle production in p+A and d+A collisions, essential for the
understanding the medium produced in high energy nucleus-nucleus collisions.Comment: 17 pages, 18 figure
Herbivory on the pedunculate oak along an urbanization gradient in Europe : Effects of impervious surface, local tree cover, and insect feeding guild
Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that-just like in non-urban areas-plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions.Peer reviewe
Three Saturn-mass planets transiting F-type stars revealed with TESS and HARPS
While the sample of confirmed exoplanets continues to increase, the
population of transiting exoplanets around early-type stars is still limited.
These planets allow us to investigate the planet properties and formation
pathways over a wide range of stellar masses and study the impact of high
irradiation on hot Jupiters orbiting such stars. We report the discovery of
TOI-615b, TOI-622b, and TOI-2641b, three Saturn-mass planets transiting main
sequence, F-type stars. The planets were identified by the Transiting Exoplanet
Survey Satellite (TESS) and confirmed with complementary ground-based and
radial velocity observations. TOI-615b is a highly irradiated (1277
) and bloated Saturn-mass planet (1.69
and 0.43) in a 4.66 day orbit transiting a 6850 K
star. TOI-622b has a radius of 0.82 and a mass of
0.30~ in a 6.40 day orbit. Despite its high
insolation flux (600 ), TOI-622b does not show any evidence
of radius inflation. TOI-2641b is a 0.37 planet in a
4.88 day orbit with a grazing transit (b = 1.04) that
results in a poorly constrained radius of 1.61.
Additionally, TOI-615b is considered attractive for atmospheric studies via
transmission spectroscopy with ground-based spectrographs and .
Future atmospheric and spin-orbit alignment observations are essential since
they can provide information on the atmospheric composition, formation and
migration of exoplanets across various stellar types.Comment: 16 pages, 17 figures, submitted to A&
Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions at âsNN = 19.6 and 22.4 GeV
Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z=7), are measured in PHOBOS. These fragments are observed in Au+Au (âsNN =19.6GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (η). The dominant multiply-charged fragment is the tightly bound helium (α), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the α fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for α and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.United States. Department of Energy (Grant DE-AC02-98CH10886)United States. Department of Energy (Grant DE-FG02-93ER40802)United States. Department of Energy (Grant DE-FG02-94ER40818)United States. Department of Energy (Grant DE-FG02-94ER40865)United States. Department of Energy (Grant DE-FG02- 99ER41099)United States. Department of Energy (Grant DE-AC02-06CH11357)National Science Foundation (U.S.) (Grant 9603486)National Science Foundation (U.S.) (Grant 0072204)National Science Foundation (U.S.) (Grant 0245011
European Society of Cardiology: Cardiovascular Disease Statistics 2017
Background: The European Society of Cardiology (ESC) Atlas has been compiled by the European Heart Agency to document cardiovascular disease (CVD) statistics of the 56 ESC member countries. A major aim of this 2017 data presentation has been to compare high income and middle income ESC member countries, in order to identify inequalities in disease burden, outcomes and service provision. Methods: The Atlas utilizes a variety of data sources, including the World Health Organization, the Institute for Health Metrics and Evaluation, and the World Bank to document risk factors, prevalence and mortality of cardiovascular disease and national economic indicators. It also includes novel ESC sponsored survey data of health infrastructure and cardiovascular service provision provided by the national societies of the ESC member countries. Data presentation is descriptive with no attempt to attach statistical significance to differences observed in stratified analyses. Results: Important differences were identified between the high income and middle income member countries of the ESC with regard to CVD risk factors, disease incidence and mortality. For both women and men, the age-standardised prevalence of hypertension was lower in high income countries (18.3% and 27.3%) compared with middle income countries (23.5% and 30.3%). Smoking prevalence in men (not women) was also lower (26% vs 41.3%), and together these inequalities are likely to have contributed to the higher CVD mortality in middle income countries. Declines in CVD mortality have seen cancer becoming a more common cause of death in a number of high income member countries, but in middle income countries declines in CVD mortality have been less consistent where CVD remains the leading cause of death. Inequalities in CVD mortality are emphasised by the smaller contribution they make to potential years of life lost in high income compared with middle income countries both for women (13% vs. 23%) and men (20% vs. 27%). The downward mortality trends for CVD may, however, be threatened by the emerging obesity epidemic that is seeing rates of diabetes increasing across all ESC member countries. Survey data from the National Cardiac Societies (n=41) showed that rates of cardiac catheterization and coronary artery bypass surgery, as well as the number of specialist centres required to deliver them, were greatest in the high income member countries of the ESC. The Atlas confirmed that these ESC member countries, where the facilities for the contemporary treatment of coronary disease were best developed, were often those in which declines in coronary mortality have been most pronounced. Economic resources were not the only driver for delivery of equitable cardiovascular healthcare, as some middle income ESC member countries reported rates for interventional procedures and device implantations that matched or exceeded the rates in wealthier member countries. Conclusion: In documenting national CVD statistics, the Atlas provides valuable insights into the inequalities in risk factors, healthcare delivery and outcomes of CVD across ESC member countries. The availability of these data will underpin the ESCâs ambitious mission âto reduce the burden of cardiovascular diseaseâ not only in its member countries, but also in nation states around the world
Implications of ACC/AHA Versus ESC/EAS LDL-C Recommendations for Residual Risk Reduction in ASCVD: A Simulation Study From DA VINCI
© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.[Purpose] Low-density lipoprotein cholesterol (LDL-C) recommendations differ between the 2018 American College of Cardiology/American Heart Association (ACC/AHA) and 2019 European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines for patients with atherosclerotic cardiovascular disease (ASCVD) (<â70 vs.â<â55 mg/dl, respectively). In the DA VINCI study, residual cardiovascular risk was predicted in ASCVD patients. The extent to which relative and absolute risk might be lowered by achieving ACC/AHA versus ESC/EAS LDL-C recommended approaches was simulated.[Methods] DA VINCI was a cross-sectional observational study of patients prescribed lipid-lowering therapy (LLT) across 18 European countries. Ten-year cardiovascular risk (CVR) was predicted among ASCVD patients receiving stabilized LLT. For patients with LDL-Cââ„â70 mg/dl, the absolute LDL-C reduction required to achieve an LDL-C ofâ<â70 orâ<â55 mg/dl (LDL-C of 69 or 54 mg/dl, respectively) was calculated. Relative and absolute risk reductions (RRRs and ARRs) were simulated.[Results] Of the 2039 patients, 61% did not achieve LDL-Câ<â70 mg/dl. For patients with LDL-Cââ„â70 mg/dl, median (interquartile range) baseline LDL-C and 10-year CVR were 93 (81â115) mg/dl and 32% (25â43%), respectively. Median LDL-C reductions of 24 (12â46) and 39 (27â91) mg/dl were needed to achieve an LDL-C of 69 and 54 mg/dl, respectively. Attaining ACC/AHA or ESC/EAS goals resulted in simulated RRRs of 14% (7â25%) and 22% (15â32%), respectively, and ARRs of 4% (2â7%) and 6% (4â9%), respectively.[Conclusion] In ASCVD patients, achieving ESC/EAS LDL-C goals could result in a 2% additional ARR over 10 years versus the ACC/AHA approach.This study was funded by Amgen Europe (GmbH).Peer reviewe
The Comet Interceptor Mission
Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA's F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ÎV capability of 600Â ms-1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000Â km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes - B1, provided by the Japanese space agency, JAXA, and B2 - that will follow different trajectories through the coma. While the main probe passes at a nominal 1000Â km distance, probes B1 and B2 will follow different chords through the coma at distances of 850Â km and 400Â km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission's science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule
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