The Mesozoic Era featured emplacement of a number of Large Igneous Provinces (LIPs), formed by the outpouring of millions of cubic kilometres of basaltic magma. The radiometric ages of several ...Mesozoic LIPs coincide with the dates of Oceanic Anoxic Events (OAEs). As a result of these coincidences, a causal link has been suggested, but never conclusively proven. This study explores the use of mercury as a possible direct link between the Karoo–Ferrar LIP and the coeval Toarcian OAE (T-OAE). Mercury is emitted to the atmosphere as a trace constituent of volcanic gas, and may be distributed globally before being deposited in sediments. Modern marine deposits show a strong linear correlation between mercury and organic-matter content. Results presented here indicate departures from such a simple linear relationship in sediments deposited during the T-OAE, and also during the Pliensbachian–Toarcian transition (an event that saw elevated benthic extinctions and carbon-cycle perturbations prior to the T-OAE). A number of depositional settings illustrate an increased mercury concentration in sediments that record one or both events, suggesting a rise in the depositional flux of this element. Complications to this relationship may arise from very organic-rich sediments potentially overprinting any Hg/TOC signal, whereas environments preserving negligible organic matter may leave no record of mercury deposition. However, the global distribution of coevally elevated Hg-rich levels suggests enhanced atmospheric mercury availability during the Early Toarcian, potentially aided by the apparent affinity of Hg for terrestrial organic matter, although the relative importance of aquatic vs terrestrial fixation of Hg in governing these enrichments remains uncertain. A perturbation in atmospheric Hg is most easily explained by enhanced volcanic output. It is suggested that extrusive igneous activity caused increased mercury flux to the Early Toarcian sedimentary realm, supporting the potential of this element as a proxy for ancient volcanism. This interpretation is consistent with a relationship between LIP formation and a perturbed carbon cycle during the Pliensbachian–Toarcian transition and T-OAE. The recording of these two distinct Hg excursions may also indicate that the Karoo–Ferrar LIP released volatiles in temporally distinct episodes, due either to multiple phases of magmatic emplacement or sporadic release of thermogenic gaseous products from intrusion of igneous material into volatile-rich lithologies.
•Analysis of seven Toarcian stratigraphic sections for Hg concentrations and Hg/TOC ratios.•Control analysis of an upper Jurassic section not associated with volcanism for comparison.•Evidence for two pulses of increased atmospheric mercury levels during the Early Toarcian.•Hg/TOC spikes coincide with record of Pliensbachian–Toarcian extinction and Toarcian OAE.•A global perturbation of volcanic mercury is inferred, but with locally derived complexities.
Radiotherapy for breast cancer may expose the esophagus to ionizing radiation, but no study has evaluated esophageal cancer risk after breast cancer associated with radiation dose or systemic therapy ...use.
Nested case–control study of esophageal cancer among 289 748 ≥5-year survivors of female breast cancer from five population-based cancer registries (252 cases, 488 individually matched controls), with individualized radiation dosimetry and information abstracted from medical records.
The largest contributors to esophageal radiation exposure were supraclavicular and internal mammary chain treatments. Esophageal cancer risk increased with increasing radiation dose to the esophageal tumor location (Ptrend < 0.001), with doses of ≥35 Gy associated with an odds ratio (OR) of 8.3 95% confidence interval (CI) 2.7–28. Patients with hormonal therapy ≤5 years preceding esophageal cancer diagnosis had lower risk (OR = 0.4, 95% CI 0.2–0.8). Based on few cases, alkylating agent chemotherapy did not appear to affect risk. Our data were consistent with a multiplicative effect of radiation and other esophageal cancer risk factors (e.g. smoking).
Esophageal cancer is a radiation dose-related complication of radiotherapy for breast cancer, but absolute risk is low. At higher esophageal doses, the risk warrants consideration in radiotherapy risk assessment and long-term follow-up.
Context. For over a decade, the structure of the inner cavity in the transition disk of TW Hydrae has been a subject of debate. Modeling the disk with data obtained at different wavelengths has led ...to a variety of proposed disk structures. Rather than being inconsistent, the individual models might point to the different faces of physical processes going on in disks, such as dust growth and planet formation. Aims. Our aim is to investigate the structure of the transition disk again and to find to what extent we can reconcile apparent model differences. Methods. A large set of high-angular-resolution data was collected from near-infrared to centimeter wavelengths. We investigated the existing disk models and established a new self-consistent radiative-transfer model. A genetic fitting algorithm was used to automatize the parameter fitting, and uncertainties were investigated in a Bayesian framework. Results. Simple disk models with a vertical inner rim and a radially homogeneous dust composition from small to large grains cannot reproduce the combined data set. Two modifications are applied to this simple disk model: (1) the inner rim is smoothed by exponentially decreasing the surface density in the inner ~3 AU, and (2) the largest grains (>100 μm) are concentrated towards the inner disk region. Both properties can be linked to fundamental processes that determine the evolution of protoplanetary disks: the shaping by a possible companion and the different regimes of dust-grain growth, respectively. Conclusions. The full interferometric data set from near-infrared to centimeter wavelengths requires a revision of existing models for the TW Hya disk. We present a new model that incorporates the characteristic structures of previous models but deviates in two key aspects: it does not have a sharp edge at 4 AU, and the surface density of large grains differs from that of smaller grains. This is the first successful radiative-transfer-based model for a full set of interferometric data.
We report pulsed laser deposition being a quite suitable growth method for smooth and transparent p-type copper iodide (CuI) thin films with tailored electrical properties. The film characteristics ...are strongly influenced by the temperature during growth. Increasing substrate temperatures result in significant improvements in crystallinity compared to deposition at room temperature. In contrast to other growth techniques, the hole carrier density p can be varied systematically between 5 × 1016 cm−3 and 1 × 1019 cm−3 with hole mobilities up to 20 cm2/V s for lowest p. The surfaces exhibit irregularly shaped grains, and the roughness can be decreased down to 1 nm. Furthermore, the samples exhibit high transmittance up to 90% in the visible spectrum.
Micronized Cu (μ-Cu) is used as a wood preservative, replacing toxic chromated copper arsenate (CCA). Micronized Cu is malachite Cu2CO3(OH)2 that has been milled to micron/submicron particles, with ...many particle diameters less than 100 nm, mixed with biocides and then used to treat wood. In addition to concerns about the fate of the Cu from μ-Cu, there is interest in the fate of the nano-Cu (n-Cu) constituents. We examined movement of Cu from μ-Cu-treated wood after placing treated-wood stakes into model wetland ecosystems. Release of Cu into surface and subsurface water was monitored. Surface water Cu reached maximum levels 3 days after stake installation and remained elevated if the systems remained inundated. Subsurface water Cu levels were 10% of surface water levels at day 3 and increased gradually thereafter. Sequential filtering indicated that a large portion of the Cu in solution was associating with soluble organics, but there was no evidence for n-Cu in solution. After 4 months, Cu in thin-sections of treated wood and adjacent soil were characterized with micro X-ray absorption fine structure spectroscopy (μ-XAFS). Localization and speciation of Cu in the wood and adjacent soil using μ-XAFS clearly indicated that Cu concentrations decreased over time in the treated wood and increased in the adjacent soil. However, n-Cu from the treated wood was not found in the adjacent soil or plant roots. The results of this study indicate that Cu in the μ-Cu-treated wood dissolves and migrates into adjacent soil and waters primarily in ionic form (i.e., Cu2+) and not as nano-sized Cu particles. A reduced form of Cu (Cu2S) was identified in deep soil proximal to the treated wood, indicating strong reducing conditions. The formation of the insoluble Cu2S effectively removes some portion of dissolved Cu from solution, reducing movement of Cu2+ to the water column and diminishing exposure.
Schematic depiction of wood stake placement in wetland mesocosm followed by undisturbed core sampling and preparation of wood:soil thin sections for investigation at the Advanced Photon Source (Argonne National Laboratory). Bottom section shows X–Y Cu chemistry map across wood and soil interface. Color legend refers to the relative Cu concentration observed by XAS. Display omitted
•Micronized Malachite replaces chromated copper arsenate as a wood preservative.•The concern is that nano-sized Malachite may escape from treated-wood.•Malachite treated wood in wetland mesocosms released Cu2+ to soil and water.•Wetland soil Cu speciation showed Cu(II and I) organics, Cu on Fe oxides, and Cu2S.•No evidence of nano-sized Malachite Cu2CO3(OH)2 escapement was found.
Inflammation is a known mediator of adverse ventricular remodeling after myocardial infarction (MI) that may lead to reduction of ejection fraction and subsequent heart failure. Berberine is a ...isoquinoline quarternary alkaloid from plants that has been associated with anti-inflammatory, anti-oxidative, and cardioprotective properties. Its poor solubility in aqueous buffers and its short half-life in the circulation upon injection, however, have been hampering the extensive usage of this natural product. We hypothesized that encapsulation of berberine into long circulating liposomes could improve its therapeutic availability and efficacy by protecting cardiac function against MI in vivo. Berberine-loaded liposomes were prepared by ethanol injection and characterized. They contained 0.3mg/mL of the drug and were 0.11μm in diameter. Subsequently they were tested for IL-6 secretion inhibition in RAW 264.7 macrophages and for cardiac function protection against adverse remodeling after MI in C57BL/6J mice. In vitro, free berberine significantly inhibited IL-6 secretion (IC50=10.4μM), whereas encapsulated berberine did not as it was not released from the formulation in the time frame of the in vitro study. In vivo, berberine-loaded liposomes significantly preserved the cardiac ejection fraction at day 28 after MI by 64% as compared to control liposomes and free berberine. In conclusion, liposomal encapsulation enhanced the solubility of berberine in buffer and preserves ejection fraction after MI. This shows that delivery of berberine-loaded liposomes significantly improves its therapeutic availability and identifies berberine-loaded liposomes as potential treatment of adverse remodeling after MI.
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The outcome of encounters between predators and prey affects predation rates and ultimately population dynamics. Determining how environmental features influence predation rates helps guide ...conservation and management efforts. We studied where gray wolves (Canis lupus Linnaeus, 1758) and coyotes (Canis latrans Say, 1823) killed white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) in northern Wisconsin, USA. We monitored 499 white-tailed deer for cause-specific mortality between 2011 and 2014 using VHF radio collars. We investigated the locations of 125 deer mortalities and determined that 63 were canid (wolf or coyote) kill sites. We analyzed spatial patterns of kill sites using resource selection functions in a model selection framework, incorporating environmental variables including vegetative cover, human development, snow depth, and water. We found no evidence that vegetative cover or human development affected predation risk; however, we did find that increasing snow depth resulted in increased relative predation risk. This finding is consistent with existing research on the influence of snow cover on white-tailed deer survival. Our results suggest that understanding the spatial and temporal patterns of white-tailed deer predation requires a better understanding of snow depth variation in space and time. As climate change scenarios predict changes in snowfall throughout the northern hemisphere, understanding the effect on predator–prey spatial dynamics will be important for management and conservation efforts.
Background The Community Preventive Services Task Force recommends combined diet and physical activity promotion programs for people at increased risk of type 2 diabetes, as evidence continues to ...show that intensive lifestyle interventions are effective for overweight individuals with prediabetes. Purpose To illustrate the potential clinical and economic benefits of treating prediabetes with lifestyle intervention to prevent or delay onset of type 2 diabetes and sequelae. Methods This 2014 analysis used a Markov model to simulate disease onset, medical expenditures, economic outcomes, mortality, and quality of life for a nationally representative sample with prediabetes from the 2003−2010 National Health and Nutrition Examination Survey. Modeled scenarios used 10-year follow-up results from the lifestyle arm of the Diabetes Prevention Program and Outcomes Study versus simulated natural history of disease. Results Over 10 years, estimated average cumulative gross economic benefits of treating patients who met diabetes screening criteria recommended by the ADA ($26,800) or USPSTF ($24,700) exceeded average benefits from treating the entire prediabetes population ($17,800). Estimated cumulative, gross medical savings for these three populations averaged $10,400, $11,200, and $6,300, respectively. Published estimates suggest that opportunistic screening for prediabetes is inexpensive, and lifestyle intervention similar to the Diabetes Prevention Program can be achieved for ≤$2,300 over 10 years. Conclusions Lifestyle intervention among people with prediabetes produces long-term societal benefits that exceed anticipated intervention costs, especially among prediabetes patients that meet the ADA and USPSTF screening guidelines.
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