118,130 research outputs found
Influence on fluid dynamics of coronary artery outlet angle variation in artificial aortic root prosthesis
No full textAbstract Background Because of higher life expectancy, the number of elderly patients today with degenerative aortic diseases is on the increase. Often artificial aortic roots are needed to replace the native tissue. This surgical procedure requires re-implantation of the previous separated coronary arteries into the wall of the prosthesis. Regardless of the prosthesis type, changes in the reinsertion technique, e.g., the variation of the outlet angle of the coronary arteries, could influence the coronary blood flow. Whether the prosthesis type or the outlet angle variation significantly improves the blood circulation and lowers the risk of coronary insufficiency is still an open question. The numerical calculations presented can help to clear up these disputable questions. Methods Two simplified base geometries are used for simulating the blood flow in order to determine velocity and pressure distributions. One model uses a straight cylindrical tube to approximate the aortic root geometry; the other uses a sinus design with pseudosinuses of Valsalva. The coronary outlet angle of the right coronary artery was discretely modified in both models in the range from 60° to 120°. The pressure and velocity distributions of both models are compared in the ascending aorta as well as in the right and the left coronary artery. Results The potentially allowed and anatomic limited variation of the outlet angle influences the pressure only a little bit and shows a very slight relative maximum between 70° and 90°. The sinus design and variations of the outlet angle of the coronary arteries were able to minimally optimize the perfusion pressure and the velocities in the coronary circulation, although the degree of such changes is rather low and would probably not achieve any clinical influence. Conclusion Our results show that surgeons should feel relatively free to vary the outlet angle within the anatomic structural conditions when employing the technique of coronary reinsertion.</p
Simulation of the fluid dynamics in artificial aortic roots: comparison of two different types of prostheses
No full textAs a consequence of the growing number of elderly people, the incidence of degenerative aortic diseases continues to increase. Often, artificial aortic roots are needed to replace the native tissue. Some physical characteristics of the artificial aortic root, however, are quite different from native aorta and need to be optimized. The supposed benefit of a prosthesis with artificial sinuses of Valsalva could first be checked by numerical calculations. Two simplified base geometries were used for simulating the flow and pressure distributions, especially in the coronary arteries. One model approximates the ascending aorta as a tube, and the other uses a design with toroidal dilation of the aortic root to approximate the native geometry of the sinuses of Valsalva. The flow and pressure distributions in both models were compared in the ascending aorta as well as in the right and the left coronary arteries. Both the pressure and the velocity distribution in the coronary artery region were not significantly higher in the model with the sinus design compared to the tube model. The sinus design only slightly increased the mean pressures and the velocities in both the ascending aorta and in the coronary arteries. Higher pressure in the coronary arteries should improve the blood circulation and decrease the risk of a surgery-related coronary incident. The sinus design did not show the hopedfor benefits, and therefore it is only a minor factor in optimizing future aortic root prostheses
Political Accountability in the European Union. Conceptual Analysis and Future Prospects
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ともにいればいるほど、我々は幸せである：ジンバブエのメンタルヘルスにおけるピア・ミュージック より一緒に、より幸せに：ジンバブエの精神保健治療における、仲間どうしでの音楽
No full textRuth Verheyは、ジンバブエのHarareで、メンタルヘルスケア主導を基盤とする包括的グループ「なかまのベンチ［Friendship Bench］」の発展と運営に携わる臨床心理士である。2013年、彼女はニューヨーク市から音楽療法士のJeffrey Angellを招聘し、Harare病院において毎週行われるZeebagサポートグループを設立した。Zeebagグループはうつを患う8人の女性で構成されている。このエッセイは、Jeffreyがその経験を一人称で述べると同時に、音楽や音楽プロセスについて、またこれらがいかにしてFriendship Benchのピア・エンパワメント・モデルに統合されていったかについて報告する。Ruth Verhey is a clinical psychologist involved in developing and running the Friendship Bench, a comprehensive, group based mental healthcare initiative in Harare, Zimbabwe. In 2013, she invited Jeffrey Angell, a music therapist from New York City, to facilitate one of weekly Zeebag support groups at Harare Hospital. The Zeebag group is comprised of eight women who suffer from depression. The essay provides Jeffrey\u27s first person accounts of this experience, as well as describing the music, music process, and how these intergrate into the peer empowerment model of the Frienship Bench.Ruth Verhey est un psychologue clinicien impliqué dans le développement et l\u27exécution du Banc d\u27amitié, un initiative basée sur groupe globale de soins de santé mentale à Harare, au Zimbabwe. En 2013, elle a invité Jeffrey Angell, un musicothérapeute de New York, afin de faciliter l\u27un des groupes de soutien Zeebag hebdomadaires à l\u27hôpital de Harare. Le groupe Zeebag est composé de huit femmes qui souffrent de dépression. L\u27essai fournit des premiers comptes de personne de Jeffrey de cette expérience, ainsi que décrire la musique, le processus de la musique, et comment ceux-ci intergré dans le modèle d\u27autonomisation par les pairs du Banc Amitié
Political Accountability in the EU Member States. Different Concepts and Practical Implications
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Regional differences in effects of APOE epsilon4 on cognitive impairment in non-demented subjects
No full textItem does not contain fulltextBACKGROUND: The APOE epsilon4 allele is a risk factor for Alzheimer's disease (AD). APOE epsilon4 is common in non-demented subjects with cognitive impairment. In both healthy people and people with AD, its prevalence has a north-south gradient across Europe. In the present study, we investigated whether the relation between the APOE epsilon4 allele and cognitive impairment varied across Northern, Middle and Southern Europe. We also investigated whether a north-south gradient existed in subjects with subjective cognitive impairment (SCI), amnestic mild cognitive impairment (MCI) and non-amnestic MCI. METHODS: Data from 16 centers across Europe were analyzed. RESULTS: A north-south gradient in APOE epsilon4 prevalence existed in the total sample (62.7% for APOE epsilon4 carriers in the northern region, 42.1% in the middle region, and 31.5% in the southern region) and in subjects with SCI and amnestic MCI separately. Only in Middle Europe was the APOE epsilon4 allele significantly associated with poor performance on tests of delayed recall and learning, as well as with the amnestic subtype of MCI. CONCLUSION: The APOE epsilon4 allele frequencies in subjects with SCI and amnestic MCI have a north-south gradient. The relation between the APOE epsilon4 allele and cognition is region dependent
The effect of silent gaps on temporal weights in loudness judgments
No full textThese are the trial-by-trial data from Fischenich, A., Hots, J., Verhey, J. L., & Oberfeld, D. (2020). The effect of silent gaps on temporal weights in loudness judgments. Hearing Research, 395. https://doi.org/10.1016/j.heares.2020.108028.
The study is part of the research project Development of a dynamic loudness model including perceptual weights (https://osf.io/ysmdp)
Managerialism and politicization in the Dutch civil service
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