18 research outputs found

    Acute Sleep Deprivation and Circadian Misalignment Associated with Transition onto the First Night of Work Impairs Visual Selective Attention

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    Background: Overnight operations pose a challenge because our circadian biology promotes sleepiness and dissipates wakefulness at night. Since the circadian effect on cognitive functions magnifies with increasing sleep pressure, cognitive deficits associated with night work are likely to be most acute with extended wakefulness, such as during the transition from a day shift to night shift. Methodology/Principal Findings: To test this hypothesis we measured selective attention (with visual search), vigilance (with Psychomotor Vigilance Task [PVT]) and alertness (with a visual analog scale) in a shift work simulation protocol, which included four day shifts followed by three night shifts. There was a nocturnal decline in cognitive processes, some of which were most pronounced on the first night shift. The nighttime decrease in visual search sensitivity was most pronounced on the first night compared with subsequent nights (p = .04), and this was accompanied by a trend towards selective attention becoming ‘fast and sloppy’. The nighttime increase in attentional lapses on the PVT was significantly greater on the first night compared to subsequent nights (p<.05) indicating an impaired ability to sustain focus. The nighttime decrease in subjective alertness was also greatest on the first night compared with subsequent nights (p<.05). Conclusions/Significance: These nocturnal deficits in attention and alertness offer some insight into why occupational errors, accidents, and injuries are pronounced during night work compared to day work. Examination of the nighttime vulnerabilities underlying the deployment of attention can be informative for the design of optimal work schedules and the implementation of effective countermeasures for performance deficits during night work

    DNA-Origami Enabled Distance-Dependent Sensing

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    Localized surface plasmon resonance is a popular optical detection technique due to its ease of use. However, the main issues of this technique are its selectivity and sensitivity towards (small) single molecules. We address these challenges by introducing a distance-dependent plasmonic sensing method based on a gold nanoparticle (AuNP) tethered by a single DNA hairpin to a gold film (Au-film). The plasmonic properties of a AuNP enable us to distinguish the z-height of the particle. In the absence of a target sequence, the hairpin keeps the AuNP close to the Au-film, while hybridization with a target sequence results in an extended state of the DNA tether. We experimentally confirmed the assembly of this sensor and by simulations, predicted the plasmonic signal of the two states. Finally, we showed experimental results as proof of concept of our sensing method

    An optical aptasensor for real-time quantification of endotoxin: From ensemble to single-molecule resolution

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    Endotoxin is a deadly pyrogen, rendering it crucial to monitor with high accuracy and efficiency. However, current endotoxin detection relies on multistep processes that are labor-intensive, time-consuming, and unsustainable. Here, we report an aptamer-based biosensor for the real-time optical detection of endotoxin. The endotoxin sensor exploits the distance-dependent scattering of gold nanoparticles (AuNPs) coupled to a gold nanofilm. This is enabled by the conformational changes of an endotoxin-specific aptamer upon target binding. The sensor can be used in an ensemble mode and single-particle mode under dark-field illumination. In the ensemble mode, the sensor is coupled with a microspectrometer and exhibits high specificity, reliability (i.e., linear concentration to signal profile in logarithmic scale), and reusability for repeated endotoxin measurements. Individual endotoxins can be detected by monitoring the color of single AuNPs via a color camera, achieving single-molecule resolution. This platform can potentially advance endotoxin detection to safeguard medical, food, and pharmaceutical products

    An optical aptasensor for real-time quantification of endotoxin: From ensemble to single-molecule resolution

    Get PDF
    Endotoxin is a deadly pyrogen, rendering it crucial to monitor with high accuracy and efficiency. However, current endotoxin detection relies on multistep processes that are labor-intensive, time-consuming, and unsustainable. Here, we report an aptamer-based biosensor for the real-time optical detection of endotoxin. The endotoxin sensor exploits the distance-dependent scattering of gold nanoparticles (AuNPs) coupled to a gold nanofilm. This is enabled by the conformational changes of an endotoxin-specific aptamer upon target binding. The sensor can be used in an ensemble mode and single-particle mode under dark-field illumination. In the ensemble mode, the sensor is coupled with a microspectrometer and exhibits high specificity, reliability (i.e., linear concentration to signal profile in logarithmic scale), and reusability for repeated endotoxin measurements. Individual endotoxins can be detected by monitoring the color of single AuNPs via a color camera, achieving single-molecule resolution. This platform can potentially advance endotoxin detection to safeguard medical, food, and pharmaceutical products.</p

    An optical aptasensor for real-time quantification of endotoxin: From ensemble to single-molecule resolution

    No full text
    Endotoxin is a deadly pyrogen, rendering it crucial to monitor with high accuracy and efficiency. However, current endotoxin detection relies on multistep processes that are labor-intensive, time-consuming, and unsustainable. Here, we report an aptamer-based biosensor for the real-time optical detection of endotoxin. The endotoxin sensor exploits the distance-dependent scattering of gold nanoparticles (AuNPs) coupled to a gold nanofilm. This is enabled by the conformational changes of an endotoxin-specific aptamer upon target binding. The sensor can be used in an ensemble mode and single-particle mode under dark-field illumination. In the ensemble mode, the sensor is coupled with a microspectrometer and exhibits high specificity, reliability (i.e., linear concentration to signal profile in logarithmic scale), and reusability for repeated endotoxin measurements. Individual endotoxins can be detected by monitoring the color of single AuNPs via a color camera, achieving single-molecule resolution. This platform can potentially advance endotoxin detection to safeguard medical, food, and pharmaceutical products.ChemE/Product and Process Engineerin

    A national FFQ for the Netherlands (the FFQ-NL 1.0): validation of a comprehensive FFQ for adults

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    A standardised, national, 160-item FFQ, the FFQ-NL 1.0, was recently developed for Dutch epidemiological studies. The objective was to validate the FFQ-NL 1.0 against multiple 24-h recalls (24hR) and recovery and concentration biomarkers. The FFQ-NL 1.0 was filled out by 383 participants (25-69 years) from the Nutrition Questionnaires plus study. For each participant, one to two urinary and blood samples and one to five (mean 27) telephone-based 24hR were available. Group-level bias, correlation coefficients, attenuation factors, de-attenuated correlation coefficients and ranking agreement were assessed. Compared with the 24hR, the FFQ-NL 1.0 estimated the intake of energy and macronutrients well. However, it underestimated intakes of SFA and trans-fatty acids and alcohol and overestimated intakes of most vitamins by &gt;5 %. The median correlation coefficient was 039 for energy and macronutrients, 030 for micronutrients and 030 for food groups. The FFQ underestimated protein intake by an average of 16 % and K by 5 %, relative to their urinary recovery biomarkers. Attenuation factors were 044 and 046 for protein and K, respectively. Correlation coefficients were 043-047 between (fatty) fish intake and plasma EPA and DHA and 024-043 between fruit and vegetable intakes and plasma carotenoids. In conclusion, the overall validity of the newly developed FFQ-NL 1.0 was acceptable to good. The FFQ-NL 1.0 is well suited for future use within Dutch cohort studies among adults

    Invasion risks posed by the aquarium trade and live fish markets on the Laurentian Great Lakes

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    International trade is an important mechanism for global non-indigenous species introductions, which have had profound impacts on the biodiversity of aquatic ecosystems including the Laurentian Great Lakes. The best-documented vector by which non-indigenous species have entered the Great Lakes is ballast water discharged by transoceanic ships. A variety of potential alternative vectors exist, including the intentional release of aquarium or food organisms. To assess whether these vectors pose a significant invasion risk for the Great Lakes, we surveyed fish sold live in markets and fish, mollusks and macrophytes sold in pet and aquarium stores within the Great Lakes watershed. We evaluated invasion risk using information on species\u27 thermal tolerance, history of invasion elsewhere, and potential propagule loads as indicated by frequency of occurrence in shops. Our research suggests that both the aquarium industry and live fish markets represent potential sources of future invaders to the Great Lakes, including several aquarium fishes and macrophytes, as well as Asian carp species sold in fish markets. Currently, few regulatory mechanisms exist to control these potential vectors. © Springer 2005

    The Maastricht FFQ: Development and validation of a comprehensive food frequency questionnaire for the Maastricht study.

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    The aim of this study was to develop and validate a comprehensive food frequency questionnaire (FFQ) for The Maastricht Study, a population-based prospective cohort study in Maastricht, The Netherlands. Item selection for the FFQ was based on explained variation and contribution to intake of energy and 24 nutrients. For validation, the FFQ was completed by 135 participants (25-70 y of age) of the Nutrition Questionnaires plus study. Per person, on average 2.8 (range 1-5) telephone-based 24-h dietary recalls (24HRs), two 24-h urinary samples, and one blood sample were available. Validity of 54 nutrients and 22 food groups was assessed by ranking agreement, correlation coefficients, attenuation factors, and ultimately deattenuated correlation coefficients (validity coefficients). Median correlation coefficients for energy and macronutrients, micronutrients, and food groups were 0.45, 0.36, and 0.38, respectively. Median deattenuated correlation coefficients were 0.53 for energy and macronutrients, 0.45 for micronutrients, and 0.64 for food groups, being >0.50 for 18 of 22 macronutrients, 16 of 30 micronutrients and >0.50 for 17 of 22 food groups. The FFQ underestimated protein and potassium intake compared with 24-h urinary nitrogen and potassium excretion by -18% and -2%, respectively. Correlation coefficients ranged from 0.50 and 0.55 for (fatty) fish intake and plasma eicosapentaenoic acid and docosahexaenoic acid, and from 0.26 to 0.42 between fruit and vegetable intake and plasma carotenoids. Overall, the validity of the 253-item Maastricht FFQ was satisfactory. The comprehensiveness of this FFQ make it well suited for use in The Maastricht Study and similar populations
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