20 research outputs found
Quantitative estimation of alpha-PVP metabolites in urine by GC-APCI-QTOFMS with nitrogen chemiluminescence detection based on parent drug calibration
No full textGas chromatography (GC) hyphenated with nitrogen chemiluminescence detection (NCD) and quadrupole time-of-flight mass spectrometry (QTOFMS) was applied for the first time to the quantitative analysis of new psychoactive substances (NPS) in urine, based on the N-equimolar response of NCD. A method was developed and validated to estimate the concentrations of three metabolites of the common stimulant NPS alpha-pyrrolidinovalerophenone (alpha-PVP) in spiked urine samples, simulating an analysis having no authentic reference standards for the metabolites and using the parent drug instead for quantitative calibration. The metabolites studied were OH-alpha-PVP (M1), 2 ''-oxo-alpha-PVP (M3), and N,N-bis-dealkyl-PVP (2-amino-1-phenylpentan-1-one; M5). Sample preparation involved liquid-liquid extraction with a mixture of ethyl acetate and butyl chloride at a basic pH and subsequent silylation of the sec-hydroxyl and prim-amino groups of M1 and M5, respectively. Simultaneous compound identification was based on the accurate masses of the protonated molecules for each compound by QTOFMS following atmospheric pressure chemical ionization. The accuracy of quantification of the parent-calibrated NCD method was compared with that of the corresponding parent-calibrated QTOFMS method, as well as with a reference QTOFMS method calibrated with the authentic reference standards. The NCD method produced an equally good accuracy to the reference method for alpha-PVP, M3 and M5, while a higher negative bias (25%) was obtained for M1, best explainable by recovery and stability issues. The performance of the parent-calibrated QTOFMS method was inferior to the reference method with an especially high negative bias (60%) for M1. The NCD method enabled better quantitative precision than the QTOFMS methods To evaluate the novel approach in casework, twenty post-mortem urine samples previously found positive for alpha-PVP were analyzed by the parent calibrated NCD method and the reference QTOFMS method. The highest difference in the quantitative results between the two methods was only 33%, and the NCD method's precision as the coefficient of variation was better than 13%. The limit of quantification for the NCD method was approximately 0.25 mg/mL in urine, which generally allowed the analysis of alpha-PVP and the main metabolite M1. However, the sensitivity was not sufficient for the low concentrations of M3 and M5. Consequently, while having potential for instant analysis of NPS and metabolites in moderate concentrations without reference standards, the NCD method should be further developed for improved sensitivity to be more generally applicable. (c) 2018 Elsevier B.V. All rights reserved.Peer reviewe
n-Hexane
No full textPrepared by Research Triangle Institute under Contract No. 205-93-0606 to the U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry.Chemical manager(s)/author(s): M. Olivia Harris, James Corcoran.Includes bibliographical references (p. 201-223).205-93-060
Toxicological profile for hydraulic fluids
No full textPrepared by: Research Triangle Institute under Contract no. 205-93-0606 for: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry.Chemical manager(s)/author(s): M. Olivia Harris, Peter McClure, Robert L. Chessin, James J. Corcoran.Includes bibliographical references (p. 317-336).205-93-0606 fo
Toxicological profile for dinitrophenols
No full text"This edition supersedes any previously released draft or final profile."--p. iii.Prepared by Research Triangle Institute under contract no. 205-93-0606; prepared for: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry.Chemical manager(s)/author(s): M. Olivia Harris, James J. Corcoran.Includes bibliographical references.205-93-060
Pneumococcal meningitis in adults
No full textCopyright It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content licence (lik
Removing Redundant Arguments Automatically
No full textThe application of automatic transformation processes during the formal development and optimization of programs can introduce encumbrances in the generated code that programmers usually (or presumably) do not write. An example is the introduction of redundant arguments in the functions defined in the program. Redundancy of a parameter means that replacing it by any expression does not change the result. In this work, we provide a method for the analysis and elimination of redundant arguments in term rewriting systems as a model for the programs that can be written in more sophisticated languages. On the basis of the uselessness of redundant arguments, we also propose an erasure procedure which may avoid wasteful computations while still preserving the semantics (under ascertained conditions). A prototype implementation of these methods has been undertaken, which demonstrates the practicality of our approach
On-Demand Strategy Annotations Revisited
No full textIn functional languages such as OBJ*, CafeOBJ, and Maude, symbols are given strategy annotations that specify (the order in) which subterms are evaluated. Syntactically, strategy annotations are given either as lists of natural numbers or as lists of integers associated to function symbols whose (absolute) values refer to the arguments of the corresponding symbol
Swords from the Sea
No full textVikings, pirates, heroes, rogues, and explorers . . . all have heard the siren call of the sea, and master storyteller Harold Lamb chronicled some of their most daring exploits. This single volume contains all of Lamb’s historical seafaring stories, drawn from rare and fragile pulp magazines. Never before collected, these short stories and novels are a treasure trove of adventure. Best known for his stirring tales of Cossacks and crusaders, Lamb was no stranger to swashbuckling, and his sea stories deliver it in buckets. Sail with John Paul Jones as he fights to save the crippled Russian fleet from the Turks, one eye always alert for the knives of his czarist rivals. Venture across the desert with a lone American on a desperate venture against the Barbary corsairs. Seek the Northeast Passage, beset by ice, storms, and traitors from within, at the side of explorer Ralph Thorne. Ride the whale road with the Vikings, plying their swords from Iceland to Byzantium. Introduced by best-selling author S. M. Stirling, this volume concludes with a rare behind-the-scenes look at Harold Lamb’s writing secrets, penned by the editor who made him famous
Meditation music improved the quality of suturing in an experimental bypass procedure
No full textBackgroundNeurosurgeons are vulnerable to additional noise in their natural operating environment. Noise exposure is associated with reduced cognitive function, inability to concentrate, and nervousness. Mediation music provides an opportunity to create a calmer environment which may reduce stress during surgery.MethodsA pilot study was performed to find a suitable task, meditation music of surgeon's choice, and operation noise and to reach a certain level of training. For the main experiment, two neurosurgeons with different microsurgical experience used real operation noise and meditation music with delta waves as mediating music. Each surgeon performed 10 training bypasses (five with noise and five with music) with 16 stitches in each bypass. The total time to complete 16 stitches, a number of unachieved movements (N.U.Ms), length of thread consumed, and distribution of the stitches were quantified from the recorded videos and compared in both groups.ResultsA N.U.Ms were significantly reduced from 10938 with operation room (OR) noise to 38 +/- 13 (pPeer reviewe
Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to static vs. dynamic light exposure in upper mixed-layer summer sea waters
No full text16 pages, 8 figures, 1 tableMicrobial plankton experience short-term fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, fast repetition rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a subtle disruption of the photoinhibition and photoacclimation processes associated with ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions. © 2013 Author(s)M. G. acknowledges the receipt of a CSIC JAE scholarship. This work was supported by the (former) Spanish Ministry of Science and Innovation through the project SUMMER (CTM2008-03309/MAR). This is a contribution of the Research Groups on Marine Biogeochemistry and Global Change and on Aquatic Microbial Food Webs, supported by the Generalitat de CatalunyaPeer Reviewe
