Real-time measurements of PNA:DNA hybridization kinetics with silicon nanowire biosensors

Real-time electronic detection of peptide nucleic acid (PNA):DNA hybridization is demonstrated with silicon nanowire (Si-NW) biosensors. A stable baseline platform is crucial for obtaining the Si-NW response for biosensing applications. An integrated Si-NW auto-sampler is demonstrated and used for kinetic molecular binding measurements. The equilibrium association constant is determined to be KA≈7×106 M-1 in 1 mM ionic strength buffer. The surface density of hybridized DNA is determined to be ~1012 molecules/cm2 with a radiolabeled DNA-P32 assay. A 30× reduction in the measurement drift in Si-NW sensor response is obtained from 1.6 nA/hr to 0.04 nA/hr by using a differential measuremen

Top-and-side dual-view microfluidic device with embedded prism

A polydimethylsiloxane microfluidic device enabling dual-view visualization is proposed and demonstrated. A prism with a 2 mm square base was embedded beside a 300 μm-wide microchannel. In addition to ordinary visualization from the top of the device, the microchannel could be viewed from the side, and its optical path was reflected to the top by the prism. The top and side dual visualization in a single field of view was then realized with a single objective lens. The shifts in the focal point in the top and side directions were modeled, and a compensation method utilizing a flat sheet was used. After simultaneous bright-field and dark-field visualization was attained, dual-view fluorescence imaging of the fluorescent solution and cells was realized

Large area metal nanowire arrays with submicron pitch and tunable sub-20 nm nanogaps

We present a new top-down nanofabrication technology to realize large area metal nanowire (m-NW) arrays with tunable sub-20 nm separation nanogaps without the use of chemical etching or milling of the metal layer. The nanofabrication technology is based on a self-regulating metal deposition process that is facilitated by closely spaced and isolated heterogeneous template surfaces that confines the metal deposition into two dimensions. Electrically isolated parallel arrays of m-NW can be realized with uniform and controllable nanogaps. Au-NW arrays are presented with high-density ~105 NWs cm-1, variable NW diameters down to 50 nm, variable nanogaps down to 5 nm, and very large nanogap length density ~1 km cm-2. A spatially averaged surface enhanced Raman scattering (SERS) analytical enhancement factor of (1.5±0.2)×107 is demonstrated from a benzenethiol monolayer chemisorbed on a Au-NW array substrat

Webinar: A Faculty Perspective on COIL: A Sheridan Experience!

During the winter 2021 semester, two pilot Collaborative Online International Learning(COIL) courses were conducted within Sheridan - one within the Faculty of Humanities and Social Sciences (FHASS) and the other within Pilon School of Business (PSB). This webinar aims to capitalize on the knowledge gained by our Sheridan members from those pilot courses and learn from their experiences to benefit others moving forward. We will also highlight the different services available for our faculty and staff to support them throughout their COIL journey. Speakers: Peter Galambos, Professor, Faculty of Humanities and Social Sciences – Sheridan Mark Weaver, Professor, Pilon School of Business – Sheridan Stan Kamzol, Professor and International Academic Exchange Coordinator, Pilon School of Business – Sheridan Edwin van den Berg, Professor - Saxion University of Applied Sciences Moderated by: Amira El Masri, Director of the Centre for Global Education and Internationalization – Sheridanhttps://source.sheridancollege.ca/cgei_events/1000/thumbnail.jp

Web-based guided self-help cognitive behavioral therapy–enhanced versus treatment as usual for binge-eating disorder: a randomized controlled trial protocol

Binge-eating disorder (BED) is a psychiatric disorder characterized by recurrent episodes of eating a large amount of food in a discrete period of time while experiencing a loss of control. Cognitive behavioral therapy-enhanced (CBT-E) is a recommended treatment for binge-eating disorder and is typically offered through 20 sessions. Although binge-eating disorder is highly responsive to CBT-E, the cost of treating these patients is high. Therefore, it is crucial to evaluate the efficacy of low-intensity and low-cost treatments for binge-eating disorder that can be offered as a first line of treatment and be widely disseminated. The proposed noninferiority randomized controlled trial aims to determine the efficacy of web-based guided self-help CBT-E compared to treatment-as-usual CBT-E. Guided self-help will be based on a self-help program to stop binge eating, will be shorter in duration and lower intensity, and will require fewer therapist hours. Patients with binge-eating disorder (N = 180) will be randomly assigned to receive guided self-help or treatment-as-usual. Assessments will take place at baseline, mid-treatment, at the end of treatment, and at 20- and 40-weeks post-treatment. Treatment efficacy will be measured by examining the reduction in binge-eating days in the previous 28 days between baseline and the end of treatment between groups, with a noninferiority margin (Δ) of 1 binge-eating day. Secondary outcomes will include full remission, body shape dissatisfaction, therapeutic alliance, clinical impairment, health-related quality of life, attrition, and an economic evaluation to assess cost-effectiveness and cost-utility. The moderators examined will be baseline scores, demographic variables, and body mass index. It is expected that guided self-help is noninferior in efficacy compared to treatment-as-usual. The proposed study will be the first to directly compare the efficacy and economically evaluate a low-intensity and low-cost binge-eating disorder treatment compared to treatment-as-usual. If guided self-help is noninferior to treatment-as-usual in efficacy, it can be widely disseminated and used as a first line of treatment for patients with binge-eating disorder. The Dutch trial register number is R21.016. The study has been approved by the Medical Research Ethics Committees United on May 25th, 2021, case number NL76368.100.21

Potential impact of chemical stress on freshwater invertebrates : A sensitivity assessment on continental and national scale based on distribution patterns, biological traits, and relatedness.

Current chemical risk assessment approaches rely on a standard suite of test species to assess toxicity to environmental species. Assessment factors are used to extrapolate from single species to communities and ecosystem effects. This approach is pragmatic, but lacks resolution in biological and environmental parameters. Novel modelling approaches can help improve the biological resolution of assessments by using mechanistic information to identify priority species and priority regions that are potentially most impacted by chemical stressors. In this study we developed predictive sensitivity models by combining species-specific information on acute chemical sensitivity (LC50 and EC50), traits, and taxonomic relatedness. These models were applied at two spatial scales to reveal spatial differences in the sensitivity of species assemblages towards two chemical modes of action (MOA): narcosis and acetylcholinesterase (AChE) inhibition. We found that on a relative scale, 46% and 33% of European species were ranked as more sensitive towards narcosis and AChE inhibition, respectively. These more sensitive species were distributed with higher occurrences in the south and north-eastern regions, reflecting known continental patterns of endemic macroinvertebrate biodiversity. We found contradicting sensitivity patterns depending on the MOA for UK scenarios, with more species displaying relative sensitivity to narcotic MOA in north and north-western regions, and more species with relative sensitivity to AChE inhibition MOA in south and south-western regions. Overall, we identified hotspots of species sensitive to chemical stressors at two spatial scales, and discuss data gaps and crucial technological advances required for the successful application of the proposed methodology to invertebrate scenarios, which remain underrepresented in global conservation priorities.</p

High SNR full brain relaxometry at 7T by accelerated MR-STAT

Purpose: To demonstrate the feasibility and robustness of the Magnetic Resonance Spin TomogrAphy in Time-domain (MR-STAT) framework for fast, high SNR relaxometry at 7T. Methods: To deploy MR-STAT on 7T-systems, we designed optimized flip-angles using the BLAKJac-framework that incorporates the SAR-constraints. Transmit RF-inhomogeneities were mitigated by including a measured (Formula presented.) -map in the reconstruction. Experiments were performed on a gel-phantom and on five volunteers to explore the robustness of the sequence and its sensitivity to (Formula presented.) inhomogeneities. The SNR-gain at 7T was explored by comparing phantom and in vivo results to MR-STAT at 3T in terms of SNR-efficiency. Results: The higher SNR at 7T enabled two-fold acceleration with respect to current 2D MR-STAT protocols at lower field strengths. The resulting scan had whole-brain coverage, with 1 x 1 x 3 mm3 resolution (1.5 mm slice-gap) and was acquired within 3 min including the (Formula presented.) -mapping. After (Formula presented.) -correction, the estimated T1 and T2 in a phantom showed a mean relative error of, respectively, 1.7% and 4.4%. In vivo, the estimated T1 and T2 in gray and white matter corresponded to the range of values reported in literature with a variation over the subjects of 1.0%–2.1% (WM-GM) for T1 and 4.3%–5.3% (WM-GM) for T2. We measured a higher SNR-efficiency at 7T (R = 2) than at 3T for both T1 and T2 with, respectively, a 4.1 and 2.3 times increase in SNR-efficiency. Conclusion: We presented an accelerated version of MR-STAT tailored to high field (7T) MRI using a low-SAR flip-angle train and showed high quality parameter maps with an increased SNR-efficiency compared to MR-STAT at 3T

Association Between Self-Reported Spinal Morning Stiffness and Radiographic Evidence of Lumbar Disk Degeneration in Participants of the Cohort Hip and Cohort Knee (CHECK) Study

BACKGROUND: Low back pain (LBP) is very common and is a main cause of limited activity and work absence. Patients with LBP may also report spinal morning stiffness; this symptom could be useful for identifying subgroups with signs and symptoms related to spinal osteoarthritis. OBJECTIVE: This study investigated whether an association exists between reported spinal morning stiffness and radiographic evidence of lumbar disk degeneration (LDD) in people with LBP and a history of pain of the hip and/or knee. DESIGN: This cross-sectional study used 8-year follow-up data from the Cohort Hip and Coh

High Fat Diet-Induced Changes in Mouse Muscle Mitochondrial Phospholipids Do Not Impair Mitochondrial Respiration Despite Insulin Resistance

BACKGROUND: Type 2 diabetes mellitus and muscle insulin resistance have been associated with reduced capacity of skeletal muscle mitochondria, possibly as a result of increased intake of dietary fat. Here, we examined the hypothesis that a prolonged high-fat diet consumption (HFD) increases the saturation of muscle mitochondrial membrane phospholipids causing impaired mitochondrial oxidative capacity and possibly insulin resistance. METHODOLOGY: C57BL/6J mice were fed an 8-week or 20-week low fat diet (10 kcal%; LFD) or HFD (45 kcal%). Skeletal muscle mitochondria were isolated and fatty acid (FA) composition of skeletal muscle mitochondrial phospholipids was analyzed by thin-layer chromatography followed by GC. High-resolution respirometry was used to assess oxidation of pyruvate and fatty acids by mitochondria. Insulin sensitivity was estimated by HOMA-IR. PRINCIPAL FINDINGS: At 8 weeks, mono-unsaturated FA (16∶1n7, 18∶1n7 and 18∶1n9) were decreased (-4.0%, p<0.001), whereas saturated FA (16∶0) were increased (+3.2%, p<0.001) in phospholipids of HFD vs. LFD mitochondria. Interestingly, 20 weeks of HFD descreased mono-unsaturated FA while n-6 poly-unsaturated FA (18∶2n6, 20∶4n6, 22∶5n6) showed a pronounced increase (+4.0%, p<0.001). Despite increased saturation of muscle mitochondrial phospholipids after the 8-week HFD, mitochondrial oxidation of both pyruvate and fatty acids were similar between LFD and HFD mice. After 20 weeks of HFD, the increase in n-6 poly-unsaturated FA was accompanied by enhanced maximal capacity of the electron transport chain (+49%, p = 0.002) and a tendency for increased ADP-stimulated respiration, but only when fuelled by a lipid-derived substrate. Insulin sensitivity in HFD mice was reduced at both 8 and 20 weeks. CONCLUSIONS/INTERPRETATION: Our findings do not support the concept that prolonged HF feeding leads to increased saturation of skeletal muscle mitochondrial phospholipids resulting in a decrease in mitochondrial fat oxidative capacity and (muscle) insulin resistance