404 research outputs found
Comparison of Echocardiographic Measurements Before and After Short and Long Duration Spaceflight
Previous echocardiography studies in astronauts before and after short duration (4 - 17 days) missions have demonstrated a decrease in resting left ventricular (LV) stroke volume (SV), but maintained ejection fraction (EF) and cardiac output. Similar studies before and after long duration (129 - 144 days) spaceflight have been rare and their overall results equivocal. The purpose of this work was to compare the echocardiographic measurements (M-mode, 2-D and Doppler) from short duration (n = 13) and long duration (n = 4) crewmembers. Compared to short duration astronauts, long duration crewmembers had a significantly greater percent decrease in EF (+6+/-0.02 vs.-10.5+/-0.03, p = 0.005) and percent fractional shortening (+7+/-0.03 vs. -11+/-0.07, p = 0.0 15), and an increase in LV end systolic volume (-12+/-0.06 vs. +39+/-0.24, p = 0.011). These data suggest a reduction in cardiac function that relates to mission duration. As the changes in blood pressure and circulating blood volume (9% - 12%) are reported to be similar after short and long duration flights, the drop in EF after longer spaceflights is likely due to a decrease in cardiac function rather than altered blood volume
Subgroup analyses from a phase 3, open-label, randomized study of eribulin mesylate versus capecitabine in pretreated patients with advanced or metastatic breast cancer
Purpose and methods: Our secondary analyses compared survival with eribulin versus capecitabine in various patient subgroups from a phase 3, open-label, randomized study. Eligible women aged ≥18 years with advanced/metastatic breast cancer and ≤3 prior chemotherapies (≤2 for advanced/metastatic disease), including an anthracycline and taxane, were randomized 1:1 to intravenous eribulin mesylate 1.4 mg/m² on days 1 and 8 or twice-daily oral capecitabine 1250 mg/m² on days 1–14 (21-day cycles). Results: In the intent-to-treat population (eribulin 554 and capecitabine 548), overall survival appeared longer with eribulin than capecitabine in various subgroups, including patients with human epidermal growth factor receptor 2-negative (15.9 versus 13.5 months, respectively), estrogen receptor-negative (14.4 versus 10.5 months, respectively), and triple-negative (14.4 versus 9.4 months, respectively) disease. Progression-free survival was similar between the treatment arms. Conclusions: Patients with advanced/metastatic breast cancer and human epidermal growth factor receptor 2-, estrogen receptor-, or triple-negative disease may gain particular benefit from eribulin as first-, second-, and third-line chemotherapies
Phase III Open-Label Randomized Study of Eribulin Mesylate Versus Capecitabine in Patients With Locally Advanced or Metastatic Breast Cancer Previously Treated With an Anthracycline and a Taxane
Purpose: This phase III randomized trial (ClinicalTrials.gov identifier: NCT00337103) compared eribulin with capecitabine in patients with locally advanced or metastatic breast cancer (MBC). Patients and Methods: Women with MBC who had received prior anthracycline- and taxane-based therapy were randomly assigned to receive eribulin or capecitabine as their first-, second-, or third-line chemotherapy for advanced/metastatic disease. Stratification factors were human epidermal growth factor receptor-2 (HER2) status and geographic region. Coprimary end points were overall survival (OS) and progression-free survival (PFS). Results: Median OS times for eribulin (n = 554) and capecitabine (n = 548) were 15.9 and 14.5 months, respectively (hazard ratio [HR], 0.88; 95% CI, 0.77 to 1.00; P = .056). Median PFS times for eribulin and capecitabine were 4.1 and 4.2 months, respectively (HR, 1.08; 95% CI, 0.93 to 1.25; P = .30). Objective response rates were 11.0% for eribulin and 11.5% for capecitabine. Global health status and overall quality-of-life scores over time were similar in the treatment arms. Both treatments had manageable safety profiles consistent with their known adverse effects; most adverse events were grade 1 or 2. Conclusion: In this phase III study, eribulin was not shown to be superior to capecitabine with regard to OS or PFS
Upper atmospheres and ionospheres of planets and satellites
The upper atmospheres of the planets and their satellites are more directly
exposed to sunlight and solar wind particles than the surface or the deeper
atmospheric layers. At the altitudes where the associated energy is deposited,
the atmospheres may become ionized and are referred to as ionospheres. The
details of the photon and particle interactions with the upper atmosphere
depend strongly on whether the object has anintrinsic magnetic field that may
channel the precipitating particles into the atmosphere or drive the
atmospheric gas out to space. Important implications of these interactions
include atmospheric loss over diverse timescales, photochemistry and the
formation of aerosols, which affect the evolution, composition and remote
sensing of the planets (satellites). The upper atmosphere connects the planet
(satellite) bulk composition to the near-planet (-satellite) environment.
Understanding the relevant physics and chemistry provides insight to the past
and future conditions of these objects, which is critical for understanding
their evolution. This chapter introduces the basic concepts of upper
atmospheres and ionospheres in our solar system, and discusses aspects of their
neutral and ion composition, wind dynamics and energy budget. This knowledge is
key to putting in context the observations of upper atmospheres and haze on
exoplanets, and to devise a theory that explains exoplanet demographics.Comment: Invited Revie
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Evaluating Local Ionization Balance in the Nightside Martian Upper Atmosphere during MAVEN Deep Dip Campaigns
Combining the Mars Atmosphere and Volatile Evolution (MAVEN) measurements of atmospheric neutral and ion densities, electron temperature, and energetic electron intensity, we perform the first quantitative evaluation of local ionization balance in the nightside Martian upper atmosphere, a condition with the electron impact ionization (EI) of CO2 exactly balanced by the dissociative recombination (DR) of ambient ions. The data accumulated during two MAVEN Deep Dip (DD) campaigns are included: DD6 on the deep nightside with a periapsis solar zenith angle (SZA) of 165 degrees, and DD3 close to the dawn terminator with a periapsis SZA of 110 degrees. With the electron temperatures at low altitudes corrected for an instrumental effect pertaining to the MAVEN Langmuir Probe and Waves, a statistical agreement between the EI and DR rates is suggested by the data below 140 km during DD6 and below 180 km during DD3, implying that electron precipitation is responsible for the nightside Martian ionosphere under these circumstances and extra sources are not required. In contrast, a substantial enhancement in EI over DR is observed at higher altitudes during both campaigns, which we interpret as a signature of plasma escape down the tail.Strategic Priority Research Program of the Chinese Academy of Sciences [XDA17010201]; National Science Foundation of China [41525015, 41774186, 41525016]; National Aeronautics and Space Administration; Swedish National Space Agency [135/13, 166/14]; Swedish Research Council [621-2013-4191]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Study of the hydrogen escape rate at Mars during Martian years 28 and 29 from comparisons between SPICAM/Mars Express observations and GCM-LMD simulations
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-499-2.-
© Author(s) 2019. CC Attribution 4.0 license. https://creativecommons.org/licenses/by/4.0/deed.esWe simulate the 3D Martian hydrogen corona during the Martian years 28 and 29 at different solar longitudes using a set of models of atomic hydrogen density from the surface to the exosphere. These simulations are compared to Mars Express / SPICAM observations and show a strong underestimate of the brightness by our models near southern summer that could be due to an underestimate of the amount of water vapor delivered to the upper atmosphere at this season
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The Morphology of the Topside Martian Ionosphere: Implications on Bulk Ion Flow
Prior to the Mars Atmosphere and Volatile Evolution mission, the only information on the composition of the Martian ionosphere came from the Viking Retarding Potential Analyzer data, revealing the presence of substantial ion outflow on the dayside of Mars. Extensive measurements made by the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer allow us to examine the morphology of the Martian ionosphere not only in unprecedented detail but also on both the dayside and the nightside of the planet. Above 300km, various ionospheric species present a roughly constant density scale height around 100km on the dayside and 180km on the nightside. An evaluation of the ion force balance, appropriate for regions with near-horizontal magnetic field lines, suggests the presence of supersonic ion outflow predominantly driven by the ambient magnetic pressure, with characteristic dayside and nightside flow velocities of 4 and 20km/s, respectively, both referred to an altitude of 500km. The corresponding total ion outflow rates are estimated to be 5x10(25)s(-1) on the dayside and 1x10(25)s(-1) on the nightside. The data also indicate a prominent variation with magnetic field orientation in that the ion distribution over regions with near-vertical field lines tends to be more extended on the dayside but more concentrated on the nightside, as compared to regions with near-horizontal field lines. These observations should have important implications on the pattern of ion dynamics in the vicinity of Mars. Plain Language Summary Prior to the Mars Atmosphere and Volatile Evolution mission, the only information on the composition of the Martian ionosphere came from the Viking Retarding Potential Analyzer data acquired on the dayside of Mars. Recently, extensive measurements made by the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer allow us to examine the Martian ionosphere not only in unprecedented detail but also on both the dayside and the nightside of the planet. By analyzing these data, we find that on each side, many of the detected ion species share a common density structure at altitudes above 300km. Meanwhile, such a structure is clearly influenced by the ambient magnetic fields, which are well known to be inhomogeneous on Mars and cluster over the Southern Hemisphere. Near strong magnetic fields, the Martian ionosphere tends to be more extended on the dayside but more concentrated on the nightside. These findings reveal the presence of supersonic ion outflow on Mars. Such an ion outflow makes a significant contribution to plasma escape, which influences the long-term evolution of the planet.National Natural Science Foundation of China [41525015, 41774186, 41525016]; Science and Technology Development Fund of Macau SAR [039/2013/A2, 119/2017/A3]; National Aeronautics and Space Administration (NASA); Swedish National Space Agency [135/13, 166/14]; Swedish Research Council (VR grant) [621-2013-4191]6 month embargo; published online: 13 February 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Composition of Titan's ionosphere
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94758/1/grl21212.pd
Health-related quality of life in patients with locally advanced or metastatic breast cancer treated with eribulin mesylate or capecitabine in an open-label randomized phase 3 trial.
The clinical benefit of eribulin versus capecitabine was evaluated using health-related quality of life (HRQoL) data from a phase 3 randomized trial in patients with pretreated advanced/metastatic breast cancer (ClinicalTrials.gov identifier: NCT00337103). The study population has been described previously (Kaufman et al. in J Clin Oncol 33:594-601, 2015). Eligible patients received eribulin (1.4 mg/m(2) intravenously on days 1 and 8) or capecitabine (1.25 g/m(2) orally twice daily on days 1-14) per 21-day cycles. HRQoL was assessed using the European Organisation for Research and Treatment of Cancer (EORTC) Quality-of-life Questionnaire-Core 30 questions (QLQ-C30) and breast module-23 questions (QLQ-BR23), administered at baseline through 24 months, until disease progression or other antitumor treatment initiation. Minimally important difference (MID) and time to symptom worsening (TSW) were investigated. 1062 (96.4 %) Patients completed the EORTC questionnaire at baseline; overall, compliance was ≥80 %. Patients receiving capecitabine versus eribulin had significantly worse symptoms (higher scores) for nausea/vomiting (MID 8; P < 0.05) and diarrhea (MID 7; P < 0.05). Treatment with eribulin versus capecitabine, led to worse systemic therapy side-effects (dry mouth, different tastes, irritated eyes, feeling ill, hot flushes, headaches, and hair loss; MID 10; P < 0.01). Clinically meaningful worsening was observed for future perspective (MID 10; P < 0.05) with capecitabine and for systemic therapy side-effects scale (MID 10; P < 0.01) with eribulin. Patients receiving capecitabine experienced more-rapid deterioration in body image (by 2.9 months) and future perspective (by 1.4 months; P < 0.05) compared with those on eribulin; the opposite was observed for systemic side-effects where patients receiving eribulin experienced more-rapid deterioration than those receiving capecitabine (by 2 months; P < 0.05). Eribulin and capecitabine were found to have similar impact on patient functioning with no overall difference in HRQoL. Patients receiving eribulin reported worse systemic side-effects of chemotherapy but reduced gastrointestinal toxicity compared with capecitabine
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