126 research outputs found

    Solid phase microextraction coupled to mass spectrometry: Via a microfluidic open interface for rapid therapeutic drug monitoring

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    Tranexamic acid (TXA) is an antifibrinolytic used during cardiac surgery that presents high inter-patient variability. High plasma concentrations have been associated with post-operative seizures. Due to the difficulties with maintaining acceptable concentrations of TXA during surgery, implementation of a point-of-care strategy for testing TXA plasma concentration would allow for close monitoring of its concentration during administration. This would facilitate timely corrections to the dosing schedule, and in effect tailor treatment for individual patient needs. In this work, a method for the rapid monitoring of TXA from plasma samples was subsequently carried out via biocompatible solid-phase microextraction (Bio-SPME) coupled directly to tandem mass spectrometry via a microfluidic open interface (MOI). MOI operates under the concept of a flow-isolated desorption volume and was designed with aims to directly hyphenate Bio-SPME to different detection and ionization systems. In addition, it allows the desorption of Bio-SPME fibers in small volumes while it concurrently continues feeding the ESI with a constant flow to minimize cross-talking and instabilities. The methodology was used to monitor six patients with varying degrees of renal dysfunction, at different time points during cardiac surgery. MOI proves to be a reliable and feasible tool for rapid therapeutic drug monitoring. Affording total times of analysis as low as 30 seconds per sample in its high throughput mode configuration while the single sample turn-around time was 15 minutes, including sample preparation. In addition, cross-validation against a standard thin film solid phase microextraction using liquid chromatography coupled to tandem mass spectrometry (TFME-LC-MS/MS) method was performed. Bland-Altman analysis was used to cross-validate the results obtained by the two methods. Data analysis demonstrated that 92% of the compared data pairs (n = 63) were distributed within the acceptable range. The data was also validated by the Passing Bablok regression, demonstrating good statistical agreement between these two methods. Finally, the currently presented method offers comparable results to the conventional liquid chromatography with acceptable RSDs, while only necessitating a fraction of the time. In this way, TXA concentration in plasma can be monitored in a close to real time throughput during surgery.Fil: Looby, Nikita T.. University of Waterloo; CanadáFil: Tascon, Marcos. University of Waterloo; Canadá. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Acquaro, Vinicius R.. Universidade de Sao Paulo; Brasil. University of Waterloo; CanadáFil: Reyes Garcés, Nathaly. Restek Corporation; Estados Unidos. University of Waterloo; CanadáFil: Vasiljevic, Tijana. University of Waterloo; CanadáFil: Gomez Rios, German Augusto. University of Waterloo; Canadá. Restek Corporation; Estados UnidosFil: Wasowicz, Marcin. Toronto General Hospital; CanadáFil: Pawliszyn, Janusz. University of Waterloo; Canad

    A wideband linear tunable CDTA and its application in field programmable analogue array

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    This document is the Accepted Manuscript version of the following article: Hu, Z., Wang, C., Sun, J. et al. ‘A wideband linear tunable CDTA and its application in field programmable analogue array’, Analog Integrated Circuits and Signal Processing, Vol. 88 (3): 465-483, September 2016. Under embargo. Embargo end date: 6 June 2017. The final publication is available at Springer via https://link.springer.com/article/10.1007%2Fs10470-016-0772-7 © Springer Science+Business Media New York 2016In this paper, a NMOS-based wideband low power and linear tunable transconductance current differencing transconductance amplifier (CDTA) is presented. Based on the NMOS CDTA, a novel simple and easily reconfigurable configurable analogue block (CAB) is designed. Moreover, using the novel CAB, a simple and versatile butterfly-shaped FPAA structure is introduced. The FPAA consists of six identical CABs, and it could realize six order current-mode low pass filter, second order current-mode universal filter, current-mode quadrature oscillator, current-mode multi-phase oscillator and current-mode multiplier for analog signal processing. The Cadence IC Design Tools 5.1.41 post-layout simulation and measurement results are included to confirm the theory.Peer reviewedFinal Accepted Versio

    College Student Mental Health: An Evaluation of the DSM-5 Self-Rated Level 1 Cross-Cutting Symptom Measure

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    © 2018 American Psychological Association. The DSM-5 Self-Rated Level 1 Cross-Cutting Symptom Measure was developed to aid in clinical decision-making for clients seeking psychiatric services and to facilitate empirical investigation of the dimensional nature of mental health issues. Preliminary evidence supports its utility with clinical samples. However, the brief, yet comprehensive structure of the DSM-5 Level 1 measure may benefit a high-risk population that is less likely to seek treatment. College students have high rates of hazardous substance use and co-occurring mental health symptoms, yet rarely seek treatment. Therefore, the current study evaluated the psychometric properties (i.e., construct and criterion-related validity) of the DSM-5 Level 1 measure with a large, diverse sample of non-treatment-seeking college/university students. Data from 7,217 college students recruited from 10 universities in 10 different states across the United States evidenced psychometric validation of the DSM-5 Level 1 measure. Specifically, we found acceptable internal consistency across multi-item DSM-5 domains and moderate to strong correlations among domains (internal validity). Further, several DSM-5 domains were positively associated with longer, validated measures of the same mental health construct and had similar strengths of associations with substance use outcomes compared to longer measures of the same construct (convergent validity). Finally, all DSM-5 domains were negatively associated with self-esteem and positively associated with other theoretically relevant constructs, such as posttraumatic stress (criterion-related validity). Taken together, the DSM-5 Level 1 measure appears to be a viable tool for evaluating psychopathology in college students. Several opportunities for clinical application and empirical investigation of the DSM-5 Level 1 measure are discussed

    CIRSE Vascular Closure Device Registry

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    The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters

    An exhibition of work by the Victorian tapestry workshop

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    An exhibition of work by the Victorian tapestry workshop Fine Arts Gallery, University Centre, Churchill Ave., Sandy Bay 24 April - 10 Ma

    Circadian Clock Gene Expression in the Coral Favia fragum over Diel and Lunar Reproductive Cycles

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    Natural light cycles synchronize behavioral and physiological cycles over varying time periods in both plants and animals. Many scleractinian corals exhibit diel cycles of polyp expansion and contraction entrained by diel sunlight patterns, and monthly cycles of spawning or planulation that correspond to lunar moonlight cycles. The molecular mechanisms for regulating such cycles are poorly understood. In this study, we identified four molecular clock genes (cry1, cry2, clock and cycle) in the scleractinian coral, Favia fragum, and investigated patterns of gene expression hypothesized to be involved in the corals' diel polyp behavior and lunar reproductive cycles. Using quantitative PCR, we measured fluctuations in expression of these clock genes over both diel and monthly spawning timeframes. Additionally, we assayed gene expression and polyp expansion-contraction behavior in experimental corals in normal light:dark (control) or constant dark treatments. Well-defined and reproducible diel patterns in cry1, cry2, and clock expression were observed in both field-collected and the experimental colonies maintained under control light:dark conditions, but no pattern was observed for cycle. Colonies in the control light:dark treatment also displayed diel rhythms of tentacle expansion and contraction. Experimental colonies in the constant dark treatment lost diel patterns in cry1, cry2, and clock expression and displayed a diminished and less synchronous pattern of tentacle expansion and contraction. We observed no pattern in cry1, cry2, clock, or cycle expression correlated with monthly spawning events suggesting these genes are not involved in the entrainment of reproductive cycles to lunar light cycles in F. fragum. Our results suggest a molecular clock mechanism, potentially similar to that in described in fruit flies, exists within F. fragum

    Negative consequences associated with dependence in daily cannabis users

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    BACKGROUND: Cannabis is the most widely consumed illicit substance in America, with increasing rates of use. Some theorists tend to link frequency of use with cannabis dependence. Nevertheless, fewer than half of daily cannabis users meet DSM-IV-TR criteria for cannabis dependence. This study seeks to determine whether the negative aspects associated with cannabis use can be explained by a proxy measure of dependence instead of by frequency of use. RESULTS: Over 2500 adult daily cannabis users completed an Internet survey consisting of measures of cannabis and other drug use, in addition to measures of commonly reported negative problems resulting from cannabis use. We compared those who met a proxy measure of DSM-IV-TR criteria for cannabis dependence (N = 1111) to those who did not meet the criteria (N = 1770). Cannabis dependent subjects consumed greater amounts of cannabis, alcohol, and a variety of other drugs. They also had lower levels of motivation, happiness, and satisfaction with life, with higher levels of depression and respiratory symptoms. CONCLUSION: Although all of our subjects reported daily use, only those meeting proxy criteria for cannabis dependence reported significant associated problems. Our data suggest that dependence need not arise from daily use, but consuming larger amounts of cannabis and other drugs undoubtedly increases problems
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