The influence of anesthesia and fluid-structure interaction on simulated shear stress patterns in the carotid bifurcation of mice

Background: Low and oscillatory wall shear stresses (WSS) near aortic bifurcations have been linked to the onset of atherosclerosis. In previous work, we calculated detailed WSS patterns in the carotid bifurcation of mice using a Fluid-structure interaction (FSI) approach. We subsequently fed the animals a high-fat diet and linked the results of the FSI simulations to those of atherosclerotic plaque location on a within-subject basis. However, these simulations were based on boundary conditions measured under anesthesia, while active mice might experience different hemodynamics. Moreover, the FSI technique for mouse-specific simulations is both time- and labor-intensive, and might be replaced by simpler and easier Computational Fluid Dynamics (CFD) simulations. The goal of the current work was (i) to compare WSS patterns based on anesthesia conditions to those representing active resting and exercising conditions; and (ii) to compare WSS patterns based on FSI simulations to those based on steady-state and transient CFD simulations. Methods: For each of the 3 computational techniques (steady state CFD, transient CFD, FSI) we performed 5 simulations: 1 for anesthesia, 2 for conscious resting conditions and 2 more for conscious active conditions. The inflow, pressure and heart rate were scaled according to representative in vivo measurements obtained from literature. Results: When normalized by the maximal shear stress value, shear stress patterns were similar for the 3 computational techniques. For all activity levels, steady state CFD led to an overestimation of WSS values, while FSI simulations yielded a clear increase in WSS reversal at the outer side of the sinus of the external carotid artery that was not visible in transient CFD-simulations. Furthermore, the FSI simulations in the highest locomotor activity state showed a flow recirculation zone in the external carotid artery that was not present under anesthesia. This recirculation went hand in hand with locally increased WSS reversal. Conclusions: Our data show that FSI simulations are not necessary to obtain normalized WSS patterns, but indispensable to assess the oscillatory behavior of the WSS in mice. Flow recirculation and WSS reversal at the external carotid artery may occur during high locomotor activity while they are not present under anesthesia. These phenomena might thus influence plaque formation to a larger extent than what was previously assumed. (C) 2016 Elsevier Ltd. All rights reserved

Operation of a high purity germanium crystal in liquid argon as a Compton suppressed radiation spectrometer

A high purity germanium crystal was operated in liquid argon as a Compton suppressed radiation spectrometer. Spectroscopic quality resolution of less than 1% of the full-width half maximum of full energy deposition peaks was demonstrated. The construction of the small apparatus used to obtain these results is reported. The design concept is to use the liquid argon bath to both cool the germanium crystal to operating temperatures and act as a scintillating veto. The scintillation light from the liquid argon can veto cosmic-rays, external primordial radiation, and gamma radiation that does not fully deposit within the germanium crystal. This technique was investigated for its potential impact on ultra-low background gamma-ray spectroscopy. This work is based on a concept initially developed for future germanium-based neutrinoless double-beta decay experiments.Comment: Paper presented at the SORMA XI Conference, Ann Arbor, MI, May 200

Good News, January 1990

A newsletter published for Deaf Catholics in Michigan, IN Good News Finding Ai

Coherence of Gray Categories via Rewriting

Over the recent years, the theory of rewriting has been extended in order to provide systematic techniques to show coherence results for strict higher categories. Here, we investigate a further generalization to low-dimensional weak categories, and consider in details the first non-trivial case: presentations of tricategories. By a general result, those are equivalent to the stricter Gray categories, for which we introduce a notion of rewriting system, as well as associated tools: critical pairs, termination orders, etc. We show that a finite rewriting system admits a finite number of critical pairs and, as a variant of Newman\u27s lemma in our context, that a convergent rewriting system is coherent, meaning that two parallel 3-cells are necessarily equal. This is illustrated on rewriting systems corresponding to various well-known structures in the context of Gray categories (monoids, adjunctions, Frobenius monoids). Finally, we discuss generalizations in arbitrary dimension

Election Reform in Virginia: Deliberation and Incremental Change

Several key factors explain the incremental approach to election law after the 2000 presidential election. The close election in Florida spurred lawmakers in Virginia to create the Joint Subcommittee Studying Virginia\u27s Election Process and Voting Technologies. This special subcommittee was formed to learn more about the capacity of election administration. Through that process, Virginia officials concluded that the election system was fundamentally sound, though they identified a need for additional resources to increase staff, improve polling place access for disabled voters, and clean up registration rolls. A declining fiscal outlook limited budget resources and constrained the legislature from adopting the joint subcommittee\u27s modest recommendations for additional spending. Interestingly, partisan differences over the most controversial issue-recounting ballots-were overcome as a result of deliberation. The joint subcommittee\u27s study created a forum within which a leading Republican senator changed his initial preference for how to recount ballots, and his view prevailed against the wishes of the Republican majority in the House of Delegates. Thus, in the case of Virginia, the deliberative process altered the policy views of a key committee leader, who in turn affected the outcome of the legislative process during the 2002 session. The legislature continued to pass incremental changes to upgrade the electoral system during 2003

EFFECTIVENESS OF SERVICE DELIVERY IN PUBLIC SECONDARY SCHOOLS: THE ROLE OF SCHOOL NEEDS IDENTIFICATION PROCEDURE AND TENDERING PROCESS

Despite the Kenyan government allocation of billions of shillings to schools each year and the existing legal frameworks, service delivery has been faced with irregular procurement procedures. Thus, the purpose of the study was to investigate the effectiveness of service delivery in public secondary schools with a school needs identification procedure and tendering process perspective. Guided by the Agency Theory and Cultural Theory, the study adopted descriptive survey method design and carried out in Likoni sub-county, Mombasa. With a sample size of 116 respondents, questionnaires were administered among schools’ principals, deputies, bursars and storekeepers. The instrument was examined for reliability at a correlation coefficient of .73. Data analysis entailed descriptive and inferential statistics using SPSS Version 24.0. The study findings showed that the element of needs identification plays a role in the culmination of the requirements which in turn has effect on service delivery in public secondary schools. The study also revealed that the influence of tendering process on service delivery is insignificant at level .05 and concludes that there is no significant relationship between tendering process and service delivery.  Article visualizations

Good News, December 1987

A newsletter published for Deaf Catholics in Michigan, IN Good News Finding Ai

Diabetes Insipidus: An Overview and a Case Report

Antidiuretic hormone (ADH, vasporessin) is an octapeptide produced in the nuclei of the anterior hypothalamus. The major source of this homrone is the supraoptic nuclei with minor production taking place in the paraventricular and filiform nuclei

PEDAL FORCES, LOWER LIMB JOINT KINEMATICS AND KINETICS IN CYCLING WITH CIRCULAR AND NON-CIRULAR CHAINRINGS

Non-circular chainrings theoretically enhance cycling performance by increasing effective chainring diameter and varying crank velocity. Yet, scientific proof has failed to consistently reproduce the theoretical benefits in cycling trials. Therefore, the aim of this study was to analyse kinematics and kinetics between circular and two different shapes of non-circular chainrings. 14 elite cyclists pedalled at two submaximal (90 rpm: 180 W, 300 W) two-minutes cycling trials using three chainrings ranging from circular to ovality of 1.10 and 1.215. A significant increase of tangential pedal forces, sagittal ankle and hip joint moments and a significant decrease of sagittal knee joint moments were observed. Non-circular chainrings do not evidently seem to enhance performance, but facilitated conditions for muscle activation as well as a reduction of knee joint moments can occur