1,015 research outputs found

    Multi-wavelength fluorescence sensing with integrated waveguides in an optofluidic chip

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    Femtosecond-laser-written integrated waveguides enable multi-wavelength fluorescence sensing of flowing biomolecules in an optofluidic chip. Fluorescence from differently labeled biomolecules with distinct absorption wavelengths, encoded by uniquely modulating each excitation beam, is detected by a color-blind photodetector, and the origin of each signal is unraveled by Fourier analysis

    Multi-color fluorescent DNA analysis in an integrated optofluidic lab-on-a-chip

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    Sorting and sizing of DNA molecules within the human genome project has enabled the genetic mapping of various illnesses. By employing tiny lab-on-a-chip devices for such DNA analysis, integrated DNA sequencing and genetic diagnostics have become feasible. However, such diagnostic chips typically lack integrated sensing capability. We address this issue by combining microfluidic capillary electrophoresis with laser-induced fluorescence detection resulting in optofluidic integration towards an on-chip bio-analysis tool [1,2]. We achieve a spatial separation resolution of 12 μm, which can enable a 20-fold enhancement in electropherogram peak resolution, leading to plate numbers exceeding one million. We demonstrate a high sizing/calibration accuracy of 99% [3], and ultrasensitive fluorescence detection (limit of detection = 65 femtomolar, corresponding to merely 2-3 molecules in the excitation/detection volume) of diagnostically relevant double-stranded DNA molecules by integrated-waveguide laser excitation. Subsequently, we introduce a principle of parallel optical processing to this optofluidic lab-on-a-chip. Different sets of exclusively color-labeled DNA fragments – otherwise rendered indistinguishable by their spatio-temporal coincidence – are traced back to their origin by modulation-frequency-encoded multi-wavelength laser excitation, fluorescence detection with a color-blind photomultiplier, and Fourier-analysis decoding. As a proof of principle, fragments from independent human genomic segments, associated with genetic predispositions to breast cancer and anemia, are extracted by multiplex ligation-dependent probe amplification, and simultaneously analyzed. Such multiple yet unambiguous optical identification of biomolecules opens new horizons for “enlightened” lab-on-a-chip devices

    Multi-point, multi-wavelength fluorescence monitoring of DNA separation in a lab-on-a-chip with monolithically integrated femtosecond-laser-written waveguides

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    Electrophoretic separation of fluorescently labeled DNA molecules in on-chip microfluidic channels was monitored by integrated waveguide arrays, with simultaneous spatial and wavelength resolution. This is an important step toward point-of-care diagnostics with multiplexed DNA assays

    The burden of parenting children with frontal lobe epilepsy

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    Objective: Caring for a child with a chronic illness adds stress to the typical parenting stress in healthy developing children. This stress can place a heavy burden on parents and may increase when a child displays problem behavior. In general, parenting and child's behavior problems are associated. Furthermore, externalizing (more outgoing) behavior is reported frequently in children with frontal lobe epilepsy (FLE). Therefore, in this study, we first investigated the burden of parents of children with FLE, and second, we investigated the relation between the experienced burden and reported behavioral problems. The validity of parents' reports on proxy measures as well as duration of epilepsy is taken into account. Methods: Thirty-one parents of children with FLE completed validated questionnaires about behavioral problems and burden of parenting. To examine if parents tend to be inconsistent or unusually negative, we used the two validity scales of the Behavioral Rating Inventory of Executive Function (BRIEF) (Negativity and Inconsistency). Results: Only parents of children with FLE who have had epilepsy for 5 years or longer report more problems on the Nijmeegse Vragenlijst voor de Opvoedingssituatie (NVOS) subscales 'Able to manage', 'Child is a burden', and 'Good Interaction' compared with the healthy controls. The subscale 'Child is a burden' significantly predicts scores in about 20% to 49% on the main scales of the Child Behavior Checklist (CBCL), the Global Executive Composite (GEC), and Behavioral Regulation Index (BRI) of the BRIEF. Only 6% of parents scored in the dinical range of the negativity scale of the BRIEF. For the inconsistency scale, this was 45%. Conclusion: Parents of children with FLE do not report excessive parental burden. Longer duration of epilepsy might be a risk factor in experiencing burden. The findings suggest a link between parental burden and behavioral problems in children with FLE. Externalizing behavioral problems are the most marked behavioral problems, which relate to the parental burden. Parents tend to be inconsistent in their ratings. (C) 2019 Elsevier Inc. All rights reserved

    The burden of parenting children with frontal lobe epilepsy

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    Objective: Caring for a child with a chronic illness adds stress to the typical parenting stress in healthy developing children. This stress can place a heavy burden on parents and may increase when a child displays problem behavior. In general, parenting and child's behavior problems are associated. Furthermore, externalizing (more outgoing) behavior is reported frequently in children with frontal lobe epilepsy (FLE). Therefore, in this study, we first investigated the burden of parents of children with FLE, and second, we investigated the relation between the experienced burden and reported behavioral problems. The validity of parents' reports on proxy measures as well as duration of epilepsy is taken into account.Methods: Thirty-one parents of children with FLE completed validated questionnaires about behavioral problems and burden of parenting. To examine if parents tend to be inconsistent or unusually negative, we used the two validity scales of the Behavioral Rating Inventory of Executive Function (BRIEF) (Negativity and Inconsistency).Results: Only parents of children with FLE who have had epilepsy for 5 years or longer report more problems on the Nijmeegse Vragenlijst voor de Opvoedingssituatie (NVOS) subscales 'Able to manage', 'Child is a burden', and 'Good Interaction' compared with the healthy controls. The subscale 'Child is a burden' significantly predicts scores in about 20% to 49% on the main scales of the Child Behavior Checklist (CBCL), the Global Executive Composite (GEC), and Behavioral Regulation Index (BRI) of the BRIEF. Only 6% of parents scored in the dinical range of the negativity scale of the BRIEF. For the inconsistency scale, this was 45%.Conclusion: Parents of children with FLE do not report excessive parental burden. Longer duration of epilepsy might be a risk factor in experiencing burden. The findings suggest a link between parental burden and behavioral problems in children with FLE. Externalizing behavioral problems are the most marked behavioral problems, which relate to the parental burden. Parents tend to be inconsistent in their ratings. (C) 2019 Elsevier Inc. All rights reserved.</p
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