Outflow boundary conditions for 3D simulations of non-periodic blood flow and pressure fields in deformable arteries

The simulation of blood flow and pressure in arteries requires outflow boundary conditions that incorporate models of downstream domains. We previously described a coupled multidomain method to couple analytical models of the downstream domains with 3D numerical models of the upstream vasculature. This prior work either included pure resistance boundary conditions or impedance boundary conditions based on assumed periodicity of the solution. However, flow and pressure in arteries are not necessarily periodic in time due to heart rate variability, respiration, complex transitional flow or acute physiological changes. We present herein an approach for prescribing lumped parameter outflow boundary conditions that accommodate transient phenomena. We have applied this method to compute haemodynamic quantities in different physiologically relevant cardiovascular models, including patient-specific examples, to study non-periodic flow phenomena often observed in normal subjects and in patients with acquired or congenital cardiovascular disease. The relevance of using boundary conditions that accommodate transient phenomena compared with boundary conditions that assume periodicity of the solution is discussed

Exploring the phase structure of lattice QCD with twisted mass quarks

The phase structure of zero temperature twisted mass lattice QCD is investigated. We find strong metastabilities in the plaquette observable when the untwisted quark mass sweeps across zero.Comment: Talks presented at Lattice2004(spectrum), 6 pages, 6 figure

The vulnerability of the European agriculture and food system for calamities and geopolitics : a stress test

During the 1960s and 1970s, the EU succeeded in becoming largely self-sufficient in food production, thus assuring its food security for the most part. However, it is unclear which areas of food security are still vulnerable and/or whether there are there new vulnerabilities. In this report we have focused on emergencies and geopolitical shocks that can have a major impact on food security, i.e. food volume. We have not included emergencies that affect food safety (such as a nuclear disaster) or emergencies that have a much broader effect than on food chains alone (such as a flu pandemic or power failure)

Finite Element Flow Simulations of the EUROLIFT DLR-F11 High Lift Configuration

This paper presents flow simulation results of the EUROLIFT DLR-F11 multi-element wing configuration, obtained with a highly scalable finite element solver, PHASTA. This work was accomplished as a part of the 2nd high lift prediction workshop. In-house meshes were constructed with increasing mesh density for analysis. A solution adaptive approach was used as an alternative and its effectiveness was studied by comparing its results with the ones obtained with other meshes. Comparisons between the numerical solution obtained with unsteady RANS turbulence model and available experimental results are provided for verification and discussion. Based on the observations, future direction for adaptive research and simulations with higher fidelity turbulence models is outlined.Comment: 52nd Aerospace Sciences Meetin

Sedation with alfentanil and propofol for rhizotomies

Background: Patient safety during sedation for closed rhizotomies is improved when analgesia is optimised, rather than relying on deep sedation for patient comfort. This retrospective study determined the appropriate effect-site concentration (Ce) for alfentanil, in combination with a constant propofol infusion, for optimal pain control during sedation for closed rhizotomies. Airway maintenance is ensured by keeping patients responsive to verbal commands, albeit at the price of inevitable ventilatory depression.Method: The records of patients who received rhizotomies over a six-month period were studied retrospectively. Sixty-three outpatients were included. Patients rated the level of analgesia with each needle placement. If the Ce for alfentanil was adequate, it was kept constant. Otherwise, it was increased in 5 ng/ml increments with each needle placement until analgesia was effective, or up to the maximum Ce for alfentanil of 100 ng/ml. Propofol infusion at a constant Ce of 200 ng/ml was added.Results: Forty-eight per cent of patients reported being comfortable at a Ce for alfentanil of 70–75 ng/ml. Only 5% of patients requested the maximum Ce for alfentanil of 100 ng/ml. All of the patients experienced ventilatory depression, but a patent airway was maintained. The haemodynamic observations were within normal limits. According to the ward records, 16% of the patients complained of nausea, and there was one incident of vomiting.Conclusion: Combining alfentanil at a Ce for alfentanil of 70–100 ng/ml with propofol at 200 ng/ml is a safe and effective method for analgesia during sedation for closed rhizotomies.Keywords: alfentanil, analgesia, procedural sedation, propofol, rhizotomy, target-controlled infusio

AIM:A Mapping Program for Infrared Spectroscopy of Proteins

[Image: see text] Here, we present a new analysis program, AIM, that allows extracting the vibrational amide-I Hamiltonian using molecular dynamics trajectories for protein infrared spectroscopy modeling. The constructed Hamiltonians can be used as input for spectral calculations allowing the calculation of infrared absorption spectra, vibrational circular dichroism, and two-dimensional infrared spectra. These spectroscopies allow the study of the structure and dynamics of proteins. We will explain the essence of how AIM works and give examples of the information and spectra that can be obtained with the program using the Trypsin Inhibitor as an example. AIM is freely available from GitHub, and the package contains a demonstration allowing easy introduction to the use of the program