Living with trimethylaminuria and body and breath malodour: personal perspectives.

BACKGROUND: Many people suffer from body and breath malodour syndromes. One of these is trimethylaminuria, a condition characterized by excretion in breath and bodily fluids of trimethylamine, a volatile and odorous chemical that has the smell of rotting fish. Trimethylaminuria can be primary, due to mutations in the gene encoding flavin-containing monooxygenase 3, or secondary, due to various causes. To gain a better understanding of problems faced by United Kingdom residents affected by body and breath malodour conditions, we conducted a survey. METHODS: Two anonymous online surveys, one for adults and one for parents/guardians of affected children, were conducted using the Opinio platform. Participants were invited via a trimethylaminuria advisory website. Questions were a mix of dropdown, checkbox and open-ended responses. Forty-four adults and three parents/guardians participated. The dropdown and checkbox responses were analysed using the Opinio platform. RESULTS: All participants reported symptoms of body/breath odour. However, not all answered every question. Twenty-three respondents experienced difficulties in being offered a diagnostic test for trimethylaminuria. Problems encountered included lack of awareness of the disorder by medical professionals and reluctance to recognise symptoms. Of those tested, 52% were diagnosed with trimethylaminuria. The main problems associated with living with body/breath malodours were bullying, harassment and ostracism in either the workplace (90%) or in social settings (88%). All respondents thought their condition had disadvantaged them in their daily lives. Open-ended responses included loss of confidence, stress, exclusion, isolation, loneliness, depression and suicidal thoughts. Respondents thought their lives could be improved by greater awareness and understanding of malodour conditions by medical professionals, employers and the general public, and appreciation that the malodour was due to a medical condition and not their fault. CONCLUSIONS: Breath and body malodour conditions can cause immense hardship and distress, both mentally and socially, having devastating effects on quality of life. It would be advantageous to establish a standardised pathway from primary care to a specialist unit with access to a robust and reliable test and diagnostic criteria. There is a need to recognise malodour disorders as a disability, giving affected individuals the same rights as those with currently recognised disabilities

Anisotropic adaptive simulation of transient flows using discontinuous Galerkin methods

An anisotropic adaptive analysis procedure based on a discontinuous Galerkin finite element discretization and local mesh modification of simplex elements is presented. The procedure is applied to transient two- and three-dimensional problems governed by Euler's equation. A smoothness indicator is used to isolate jump features where an aligned mesh metric field in specified. The mesh metric field in smooth portions of the domain is controlled by a Hessian matrix constructed using a variational procedure to calculate the second derivatives. The transient examples included demonstrate the ability of the mesh modification procedures to effectively track evolving interacting features of general shape as they move through a domain. Copyright (C) 2004 John Wiley Sons, Ltd

Parallel Automated Adaptive Procedures for Unstructured Meshes

Contents 1. Introduction 2. Parallel Control of Evolving Meshes 2.1 Mesh Data Structure to Support Geometry-Based Automated Adaptive Analysis 2.2 Partition Communication and Mesh Migration 2.2.1 Requirements of PMDB and Related Efforts 2.2.2 Distributed Mesh Model and Notation Used 2.2.3 Data Structures 2.2.4 Mesh Migration 2.2.5 Scalability of Mesh Migration and Extensions 2.3 Dynamic Load Balancing of Adaptively Evolving Meshes 2.3.1 Geometry-Based Dynamic Balancing Procedures 2.3.2 Topologically-Based Dynamic Balancing Procedures 3. Parallel Automatic Mesh Generation 3.1 Introduction 3.2 Background and Meshing Approach 3.3 Sequential Region Meshing 3.3.1 Underlying Octree 3.3.2 Template Meshing of Interior Octants 3.3.3 Face Removal 3.4 Parallel Constructs Required 3.4.1 Octree and Mesh Data Structures 3.4.2 Multiple Octant Migration 3.4.3 Dynamic Repartitioning 3.5 Parallel Region Meshing 3.5.1 Underlying Octree 3.5.2 Template Meshing of Interior Octants 3.5.3 Face Remova

CFD Application to Gun Muzzle Blast -A Validation Case Study

International audienceAccurate modeling of near-field wave propagation is critical to determine blast wave overpressure of large caliber muzzle brakes. Experimental testing to determine blast overpressure is costly, making CFD (Computational Fluid Dynamics) simulations of these flowfields a viable alternative. Techniques and specialized CFD codes are being developed in order to properly model the unsteady, very high-pressure flows of gun muzzle blast. 1-4 Two CFD codes, Fluent 6.1.11 (a prerelease version of Fluent) and the Discontinuous Galerkin Code (DG), developed at Rensselaer Polytechnic Institute were used in a comparison to experimental shadowgraph data from the 7.62 mm NATO rifle G3 using a DM-41 training round for the purpose of developing CFD modeling techniques and validation of the CFD codes. Unsteady grid adaption was used with both solvers in order to reduce solution error near unsteady blast waves and shocks. It is possible to get good results from Fluent with high levels of adaption, however DG, can model blast with courser grid adaption. It was also found that DG required an order of magnitude longer solution time than Fluent for a given number of grid elements. The 7.62 mm NATO G3 CFD precursor flow results matched experimental shadowgraph results well, however, the main propellant flow did not

Parallel Adaptive Mesh Refinement and Redistribution on Distributed Memory Computers

A procedure to support parallel refinement and redistribution of two dimensional unstructured finite element meshes on distributed memory computers is presented. The procedure uses the mesh topological entity hierarchy as the underlying data structures to easily support the required adjacency information. Mesh refinement is done by employing links back to the geometric representation to place new nodes on the boundary of the domain directly on the curved geometry. The refined mesh is then redistributed by an iterative heuristic based on the Leiss/Reddy [9] load balancing criteria. A fast parallel tree edge-coloring algorithm is used to pair processors having adjacent partitions and forming a tree structure as a result of Leiss/Reddy load request criteria. Excess elements are iteratively migrated from heavily loaded to less loaded processors until load balancing is achieved. The system is implemented on a massively parallel MasPar MP-2 system with a SIMD style of computation and uses me..