40 research outputs found

    On the origin and evolution of the material in 67P/Churyumov-Gerasimenko

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    International audiencePrimitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects

    Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

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    Survey Outcomes of Lipedema Reduction Surgery in the United States

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    Background: Lipedema is a loose connective tissue disease affecting the limbs of women, that is difficult to lose by diet, exercise, or bariatric surgery. Publications from Europe demonstrate that lipedema reduction surgery improves quality of life for women with lipedema. There are no comparable studies in the United States (USA). The aim of this study was to collect data from women with lipedema in the USA who have undergone lipedema reduction surgery in the USA to determine if quality of life, pain, and other measures improved after lipedema reduction surgery. Methods: Subjects were recruited and consented online for a 166-item questionnaire in REDCap. In total, 148 women answered the questionnaire after undergoing lipedema reduction surgery in the USA. Significance set at P < 0.05 was determined by ANOVA, Tukey's multiple comparison test, or paired t-test. Results: Quality of life improved in 84% and pain improved in 86% of patients. Ambulation improved most in lipedema Stage 3 (96%). Weight loss occurred in all stages by 3 months after surgery. Complications included growth of loose connective tissue within and outside treated areas, tissue fibrosis, anemia, blood clots, and lymphedema. Conclusions: Women with lipedema noticed significant benefits after lipedema reduction surgery in the USA. Prospective studies are needed to assess benefits and complications after lipedema reduction surgery in the USA. © 2021 Lippincott Williams and Wilkins. All rights reserved.Open access journalThis 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]

    Steroid-converting enzymes in human adipose tissues and fat deposition with a focus on AKR1C enzymes.

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    Adipocytes express various enzymes, such as aldo-keto reductases (AKR1C), 11β-hydroxysteroid dehydrogenase (11β-HSD), aromatase, 5α-reductases, 3β-HSD, and 17β-HSDs involved in steroid hormone metabolism in adipose tissues. Increased activity of AKR1C enzymes and their expression in mature adipocytes might indicate the association of these enzymes with subcutaneous adipose tissue deposition. The inactivation of androgens by AKR1C enzymes increases adipogenesis and fat mass, particularly subcutaneous fat. AKR1C also causes reduction of estrone, a weak estrogen, to produce 17β-estradiol, a potent estrogen and, in addition, it plays a role in progesterone metabolism. Functional impairments of adipose tissue and imbalance of steroid biosynthesis could lead to metabolic disturbances. In this review, we will focus on the enzymes involved in steroid metabolism and fat tissue deposition.info:eu-repo/semantics/publishe

    Standard of care for lipedema in the United States

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    Background: Lipedema is a loose connective tissue disease predominantly in women identified by increased nodular and fibrotic adipose tissue on the buttocks, hips and limbs that develops at times of hormone, weight and shape change including puberty, pregnancy, and menopause. Lipedema tissue may be very painful and can severely impair mobility. Non-lipedema obesity, lymphedema, venous disease, and hypermobile joints are comorbidities. Lipedema tissue is difficult to reduce by diet, exercise, or bariatric surgery. Methods: This paper is a consensus guideline on lipedema written by a US committee following the Delphi Method. Consensus statements are rated for strength using the GRADE system. Results: Eighty-five consensus statements outline lipedema pathophysiology, and medical, surgical, vascular, and other therapeutic recommendations. Future research topics are suggested. Conclusion: These guidelines improve the understanding of the loose connective tissue disease, lipedema, to advance our understanding towards early diagnosis, treatments, and ultimately a cure for affected individuals. © The Author(s) 2021.Open access articleThis 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]
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