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Sandra N Staeheli, Dominic Gascho, Lars C Ebert, Thomas Kraemer, Andrea E Steuer
Interpretation of postmortem morphine concentrations in forensic toxicology provides several pitfalls such as missing information on tolerance, analyte stability, or postmortem redistribution (PMR). Recently, it had been shown that computed tomography (CT)-guided collection of biopsies using a robotic arm (virtobot) provides a valuable strategy for systematic studies on time-dependent PMR. Using this technique, time-dependent PMR of morphine and its metabolites was investigated in 12 cases. At admission to the institute (t1), femoral and heart blood (right ventricle) as well as biopsies from the right lung, the right kidney, liver, spleen, and muscle tissue were collected...
December 3, 2016: International Journal of Legal Medicine
Roger Meder, Wolfgang Stahl, Paul Warburton, Sam Woolley, Scott Earnshaw, Klaus Haselhofer, Ken van Langenberg, Nick Ebdon, Roger Mulder
The reactivity of melamine-urea-formaldehyde resins is of key importance in the manufacture of engineered wood products such as medium density fibreboard (MDF) and other wood composite products. Often the MDF manufacturing plant has little available information on the resin reactivity other than details of the resin specification at the time of batch manufacture, which often occurs off-site at a third-party resin plant. Often too, fresh resin on delivery at the MDF plant is mixed with variable volume of aged resin in storage tanks, thereby rendering any specification of the fresh resin batch obsolete...
December 3, 2016: Analytical and Bioanalytical Chemistry
Sergey Tumanov, Jurre J Kamphorst
The lipidome comprises a large array of molecules with diverse physicochemical properties. Lipids are structural components of cells, act as a source of energy, and function as signaling mediators. Alterations in lipid metabolism are involved in the onset and progression of a variety of diseases, including metabolic syndrome and cancer. Because of this, interest in lipidomics, the comprehensive characterization of the lipidome by mass spectrometry, has intensified in recent years. However, obtaining a truly complete overview of all lipids in a sample has remained very challenging due to their enormous structural diversity...
December 1, 2016: Current Opinion in Biotechnology
Márton Novák, Dóra Palya, Zsolt Bodai, Zoltán Nyiri, Norbert Magyar, József Kovács, Zsuzsanna Eke
Combined cluster and discriminant analysis (CCDA) as a chemometric tool in compound specific isotope analysis of diesel fuels was studied. The stable carbon isotope ratios (δ(13)C) of n-alkanes in diesel fuel can be used to characterize or differentiate diesels originating from different sources. We investigated 25 diesel fuel samples representing 20 different brands. The samples were collected from 25 different service stations in 11 European countries over a 2 year period. The n-alkane fraction of diesel fuels was separated using solid-state urea clathrate formation combined with silica gel fractionation...
November 23, 2016: Forensic Science International
Samira Boroumand, Mansour Arab Chamjangali, Ghadamali Bagherian
A simple and sensitive double injection/single detector flow injection analysis (FIA) method is proposed for the simultaneous kinetic determination of ascorbic acid (AA) and uric acid (UA). This method is based upon the difference between the rates of the AA and UA reactions with Fe(3+) in the presence of 1, 10-phenanthroline (phen). The absorbance of Fe(2+)/1, 10-phenanthroline (Fe-phen) complex obtained as the product was measured spectrophotometrically at 510nm. To reach a good accuracy in the differential kinetic determination via the mathematical manipulations of the transient signals, different criteria were considered in the selection of the optimum conditions...
November 20, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
L Kinsman, J L Torero, J I Gerhard
Laboratory column experiments plus analytical and numerical modeling together suggest that, under certain conditions, downward organic liquid mobilization can occur and impact smoldering behavior. This applies for organic liquids mixed with inert sand subjected to smoldering as thermal treatment. The observed effects include increased peak temperatures (here by up to 35%) and increased treatment times (here by up to 30%). Downward organic liquid migration occurs when (i) injected Darcy air flux is less than a threshold value (here less than 3cm/s), (ii) treatment systems are tall (here 90cm, not 30cm), and (iii) the organic liquid is temperature-sensitive (viscosity less than 0...
November 18, 2016: Journal of Hazardous Materials
Tamara Turner-Moore, Mitch Waterman
INTRODUCTION: There is limited evaluation of clinical and theoretical claims that sexual thoughts of children and coercing others facilitate sexual offending. The nature of these thoughts (what they contain) also is unknown. AIM: To examine the relation between child or coercive sexual thoughts and sexual offending and to determine the nature of these thoughts and any differences among sexual offending (SO), non-sexual offending (NSO), and non-offending (NO) men...
November 30, 2016: Journal of Sexual Medicine
Anca Raˇdulescu, Rachel Marra
The neuronal circuit that controls obsessive and compulsive behaviors involves a complex network of brain regions (some with known involvement in reward processing). Among these are cortical regions, the striatum and the thalamus (which compose the CSTC pathway), limbic areas such as the amygdala and the hippocampus, and well as dopamine pathways. Abnormal dynamic behavior in this brain network is a hallmark feature of patients with increased anxiety and motor activity, like the ones affected by OCD. There is currently no clear understanding of precisely what mechanisms generate these behaviors...
November 30, 2016: Journal of Theoretical Biology
Christian Paret, Christine Jennen-Steinmetz, Christian Schmahl
To achieve long-term goals, organisms evaluate outcomes and expected consequences of their behaviors. Unfavorable decisions maintain many symptoms of borderline personality disorder (BPD); therefore, a better understanding of the mechanisms underlying decision-making in BPD is needed. In this review, the current literature comparing decision-making in patients with BPD versus healthy controls is analyzed. Twenty-eight empirical studies were identified through a structured literature search. The effect sizes from studies applying comparable experimental tasks were analyzed...
November 30, 2016: Neuroscience and Biobehavioral Reviews
Juan José Dorantes-Aranda, Katrina Campbell, Andrew Bradbury, Christopher T Elliott, D Tim Harwood, Shauna A Murray, Sarah C Ugalde, Katrina Wilson, Megan Burgoyne, Gustaaf M Hallegraeff
Blooms of the toxic dinoflagellate Alexandrium tamarense (Group 1) seriously impacted the Tasmanian shellfish industry during 2012 and 2015, necessitating product recalls and intensive paralytic shellfish toxin (PST) product testing. The performance of four commercial PST test kits, Abraxis™, Europroxima™, Scotia™ and Neogen™, was compared with the official AOAC LC-FLD method for contaminated mussels and oysters. Abraxis and Europroxima kits underestimated PST in 35-100% of samples when using standard protocols but quantification improved when concentrated extracts were further diluted (underestimation ≤18%)...
November 30, 2016: Toxicon: Official Journal of the International Society on Toxinology
Francesco Cubadda, Brian P Jackson, Kathryn L Cottingham, Yoshira Ornelas Van Horne, Margaret Kurzius-Spencer
Inorganic arsenic (iAs) is ubiquitous in the environment as arsenite (AsIII) and arsenate (AsV) compounds and biotransformation of these toxic chemicals leads to the extraordinary variety of organoarsenic species found in nature. Despite classification as a human carcinogen based on data from populations exposed through contaminated drinking water, only recently has a need for regulatory limits on iAs in food been recognized. The delay was due to the difficulty in risk assessment of dietary iAs, which critically relies on speciation analysis providing occurrence data for iAs in food - and not simply for total arsenic...
November 30, 2016: Science of the Total Environment
Gertjan Vancoillie, Maarten Vergaelen, Richard Hoogenboom
Size-exclusion chromatography (SEC) is amongst the most widely used polymer characterization methods in both academic and industrial polymer research allowing the determination of molecular weight and distribution parameters, i.e. the dispersity (Ɖ), of unknown polymers. The many advantages, including accuracy, reproducibility and low sample consumption, have contributed to the worldwide success of this analytical technique. The current generation of SEC systems have a stationary phase mostly containing highly porous, styrene-divinylbenzene particles allowing for a size-based separation of various polymers in solution but limiting the flow rate and solvent compatibility...
November 21, 2016: Journal of Chromatography. A
Andrew W Wharmby
An empirical formula based on viscoelastic analysis techniques that employs concepts from the fractional calculus that was used to model the dielectric behavior of materials exposed to oscillating electromagnetic fields in the radiofrequency, terahertz, and infrared bands. This work adapts and applies the formula to model viscoelastic behavior of materials that show an apparent increase of phase velocity of vibration with an increase in frequency, otherwise known as anomalous dispersion. A fractional order wave equation is derived through the application of the classic elastic-viscoelastic correspondence principle whose analytical solution is used to describe absorption and dispersion of acoustic waves in the viscoelastic material displaying anomalous dispersion in a specific frequency range...
September 2016: Journal of the Acoustical Society of America
M L Cowan, J H Page, T Norisuye, D A Weitz
Dynamic sound scattering (DSS) is a powerful acoustic technique for investigating the motion of particles or other inclusions inside an evolving medium. In DSS, this dynamic information is obtained by measuring the field autocorrelation function of the temporal fluctuations of singly scattered acoustic waves. The technique was initially introduced 15 years ago, but its technical aspects were not adequately discussed then. This paper addresses the need for a more complete account of the method by describing in detail two different implementations of this sound scattering technique, one of which is specifically adapted to a common experimental situation in ultrasonics...
September 2016: Journal of the Acoustical Society of America
Banibrata Poddar, Victor Giurgiutiu
This paper presents an inexpensive but accurate analytical method to calculate the scattering of straight-crested Lamb waves from cracks parallel to the plate surface. The same method is applicable for the disbond problem. In this method, the scatter field is expanded in terms of complex Lamb wave modes with unknown amplitudes. These unknown amplitudes are obtained from the boundary conditions using vector projection utilizing the power expression. The process works by projecting the stress conditions onto the displacement eigen-spaces of complex Lamb wave modes and vice versa...
September 2016: Journal of the Acoustical Society of America
Martin Lott, Marcel C Remillieux, Pierre-Yves Le Bas, T J Ulrich, Vincent Garnier, Cédric Payan
In this letter, the equivalence between local and global measures of nonclassical nonlinear elasticity is established in a slender resonant bar. Nonlinear effects are first measured globally using nonlinear resonance ultrasound spectroscopy (NRUS), which monitors the relative shift of the resonance frequency as a function of the maximum dynamic strain in the sample. Subsequently, nonlinear effects are measured locally at various positions along the sample using dynamic acousto elasticity testing (DAET). After correcting analytically the DAET data for three-dimensional strain effects and integrating numerically these corrected data along the length of the sample, the NRUS global measures are retrieved almost exactly...
September 2016: Journal of the Acoustical Society of America
Pablo Salas, Guillaume Fauquembergue, Stéphane Moreau
The noise of a canonical main-element/flap high-lift device (HLD) is computed directly using compressible wall-resolved Large Eddy Simulation. An experimental database for the chosen configuration allows us to successfully validate the chosen numerical approach. Both the noise sources and the far-field acoustic pressure are shown to be well predicted. Although the two elements trailing-edge noise can be observed in the near field, the flap remains as the dominant source in the far-field. The simplicity of the studied configuration enables the comparison of the validated numerical results with a recently developed analytical model that takes into account the diffraction of the flap noise by the main-element...
September 2016: Journal of the Acoustical Society of America
Valentin Meyer, Laurent Maxit, Christian Audoly
The scattered pressure from a stiffened axisymmetric submerged shell impinged by acoustic plane waves has been investigated experimentally, analytically and through numerical models. In the case where the shell is periodically stiffened, it is shown that helical, Bragg, and Bloch-Floquet waves can propagate. The influence of non-axisymmetric internal frames on these scattering phenomena is nevertheless not well known, as it can considerably increase the computational cost. To overcome this issue, the condensed transfer function (CTF) method, which has been developed to couple subsystems along linear junctions in the case of a mechanical excitation, is extended to acoustical excitations...
September 2016: Journal of the Acoustical Society of America
Tsair-Chuan Lin, Kainam Thomas Wong, Macario O Cordel, Joel Paz Ilao
A "triaxial velocity sensor" consists of three uniaxial velocity sensors, which are nominally identical, orthogonally oriented among themselves, and co-centered at one point in space. A triaxial velocity sensor measures the acoustic particle velocity vector, by its three Cartesian components, individually component-by-component, thereby offering azimuth-elevation two-dimensional spatial directivity, despite the physical compactness that comes with the collocation of its three components. This sensing system's azimuth-elevation beam-pattern has been much analyzed in the open literature, but only for an idealized case of the three uniaxial velocity sensors being exactly identical in gain...
September 2016: Journal of the Acoustical Society of America
Boris S Aronov, Corey L Bachand
Dependencies of the resonance frequencies and effective coupling coefficients for solid circular cylindrical piezoelements (discs) of finite size are considered as a function of their height-to-diameter aspect ratios, h/2a. At aspect ratios in the range of approximately 0.5 < h/2a < 1.5 the piezoelements are treated analytically, as a two degree-of-freedom coupled system by applying the coupled mode theory approach [Aronov, Bachand, and Brown, J. Acoust. Soc. Am. 126(6), 2983-2990 (2009)]. Results are presented as plots of resonance frequencies and effective coupling coefficients vs aspect ratios...
September 2016: Journal of the Acoustical Society of America
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