The astrometric Gaia-FUN-SSO observation campaign of 99 942 Apophis

Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO . The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids.Comment: Accepted for publication in A&

Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial

IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved

A large topographic feature on the surface of the trans-Neptunian object (307261) 2002 MS4_4 measured from stellar occultations

This work aims at constraining the size, shape, and geometric albedo of the dwarf planet candidate 2002 MS4 through the analysis of nine stellar occultation events. Using multichord detection, we also studied the object's topography by analyzing the obtained limb and the residuals between observed chords and the best-fitted ellipse. We predicted and organized the observational campaigns of nine stellar occultations by 2002 MS4 between 2019 and 2022, resulting in two single-chord events, four double-chord detections, and three events with three to up to sixty-one positive chords. Using 13 selected chords from the 8 August 2020 event, we determined the global elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the object's rotational information from the literature, constrains the object's size, shape, and albedo. Additionally, we developed a new method to characterize topography features on the object's limb. The global limb has a semi-major axis of 412 $\pm$ 10 km, a semi-minor axis of 385 $\pm$ 17 km, and the position angle of the minor axis is 121 $^\circ$ $\pm$ 16$^\circ$. From this instantaneous limb, we obtained 2002 MS4's geometric albedo and the projected area-equivalent diameter. Significant deviations from the fitted ellipse in the northernmost limb are detected from multiple sites highlighting three distinct topographic features: one 11 km depth depression followed by a 25$^{+4}_{-5}$ km height elevation next to a crater-like depression with an extension of 322 $\pm$ 39 km and 45.1 $\pm$ 1.5 km deep. Our results present an object that is $\approx$138 km smaller in diameter than derived from thermal data, possibly indicating the presence of a so-far unknown satellite. However, within the error bars, the geometric albedo in the V-band agrees with the results published in the literature, even with the radiometric-derived albedo

СРАВНЕНИЕ МОРФОЛОГИЧЕСКИХ И ХИМИЧЕСКИХ СВОЙСТВ СФЕРИЧЕСКИХ И ИГОЛЬЧАТЫХ КАЛЬЦИЙ-ФОСФАТНЫХ БИОНОВ

Aim. To compare morphological properties, mineral, and organic profile of spherical calcium phosphate bions (SCPB) and needle calcium phosphate bions (NCPB) for the assessment of the CPB-specific endothelial toxicity in models of mild or severe hypercalcemia/hyperphosphatemia in the further studies.Methods. Both SCPB and NCPB were artificially synthesized employing blood-mimetic medium either moderately or significantly supersaturated of calcium and phosphorus salts. Size and shape of SCPB and NCPB were investigated by scanning and transmission electron microscopy and atomic force microscopy. Elemental analysis was performed utilizing energy-dispersive X-ray spectroscopy, atomic emission spectroscopy, and CHNSO analysis, functional groups were examined using Fourier-transform infrared spectroscopy and Raman spectroscopy while chemical formula was identified by X-ray powder diffraction analysis. Protein profile of SCPB and NCPB was screened employing sodium dodecyl sulfate polyacrylamide gel electrophoresis following silver staining.Results. SCPB were visualized as crystalline spherical spongeous particles of 80-200 nm diameter and mean diameter of around 120 nm while NCPB represented needle crystals of a similar diameter. Both SCPB and NCPB had similar crystallinity, surface charge and tended to form clusters of several particles. Furthermore, both SCPB and NCPB were composed of carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus, contained phosphate (PO4 3-), carbonate (CO3 2-), and hydroxyl (OH- ) functional groups, and consisted of hydroxyapatite (Ca10(PO4 )6 (OH)2 ) and carbonate-hydroxyapatite (Ca10(PO4)3 (CO3)3 (OH)2 ). In addition, protein profile of SCPB and NCPB was similar and notable for the abundant albumin and fetuin A levels.Conclusion. Having similar size, surface charge, extent of crystallinity, and chemical composition, SCPB and NCPB possess a different shape. Цель Сравнить морфологию, минеральный и органический профиль сферических кальций-фосфатных бионов (СКФБ) и игольчатых кальций-фосфатных бионов (ИКФБ), необходимых для оценки эндотелиотоксического действия КФБ при моделировании умеренной и тяжелой гиперкальциемии/гиперфосфатемии в последующих исследованиях. Материалы и методы СКФБ и ИКФБ были искусственно синтезированы посредством умеренного и выраженного перенасыщения имитирующей состав крови среды солями кальция и фосфора. Размерность и форма СКФБ и ИКФБ были изучены при помощи сканирующей и просвечивающей электронной микроскопии и атомно-силовой микроскопии. Элементный анализ проводился посредством энергодисперсионной рентгеновской спектроскопии, атомно-эмиссионной спектроскопии и CHNSO-анализа, функциональные группы идентифицировались при помощи инфракрасной спектроскопии с преобразованием Фурье и спектроскопии комбинационного рассеяния света, формула входящих в состав бионов химических соединений и степень их кристалличности определялась методом рентгеновской порошковой дифрактометрии. Белковый профиль СКФБ и ИКФБ был исследован путем электрофореза в полиакриламидном геле в присутствии додецилсульфата натрия с последующим окрашиванием нитратом серебра. Результаты СКФБ визуализировались как кристаллические сферические частицы губчатой структуры диаметром 80–200 нм и средним диаметром около 120 нм, в то время как ИКФБ представляли собой игольчатые кристаллы такого же диаметра. Как СКФБ, так и ИКФБ имели схожий поверхностный заряд и были склонны к агрегации. СКФБ и ИКФБ состояли из углерода, кислорода, водорода, азота, кальция и фосфора, содержали фосфатные (PO4 3-), карбонатные (CO3 2-) и гидроксильные (OH- ) группы и состояли из гидроксиапатита (Ca10(PO4 ) 6 (OH)2 ) и карбонат-гидроксиапатита (Ca10(PO4 ) 3 (CO3 ) 3 (OH)2 ). Кроме того, СКФБ и ИКФБ обладали идентичной степенью кристалличности и схожим белковым профилем с преобладанием альбумина и фетуина-А над остальными белками. Заключение СКФБ и ИКФБ отличаются лишь формой, имея схожие размерность, поверхностный заряд, степень кристалличности и химический соста

The astrometric Gaia-FUN-SSO observation campaign of 99942 Apophis

© 2015 ESO. Aims. Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO. Methods. The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. Results. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids