Dynamics and ordering of weakly Brownian particles in directional drying

Drying of particle suspensions is an ubiquitous phenomenon with many natural and practical applications. In particular, in unidirectional drying, the evaporation of the solvent induces flows which accumulate particles at the liquid/air interface. The progressive build-up of a dense region of particles can be used, in particular, in the processing of advanced materials and architectures while the development of heterogeneities and defects in such systems is critical to their function. A lot of attention has thus been paid to correlate the flow and particles dynamics to the ordering of particles. However, dynamic observation at the particle scale and its correlation with local particle ordering are still missing. Here we show by measuring the particle velocities with high frame rate laser scanning confocal microscopy that the ordering of weakly Brownian particles during directional drying in a Hele-Shaw cell opened on one side depends on the particle velocity. Under the ambient and experimental conditions presented in the following, the particle velocities accumulate in two branches. A higher degree of ordering is found for the branch of faster particle velocity which we explain by an increase in the pressure drop which drags the particles into a denser packing as the flow velocity increases. This counter-intuitive behaviour is the opposite to what is found with Brownian particles, which can reorganize by Brownian motion into denser packing during drying, as long as the flow velocity is not too high. These results show that different kinetic conditions can be used to obtain dense, defect-free regions of particles after drying. In particular, it suggests that rapid, directional drying could be used to control the crystallinity of particle deposits.Comment: 10 pages, 12 figure

Energy-time entanglement preservation in plasmon-assisted light transmission

We report on experimental evidences of the preservation of energy-time entanglement for extraordinary plasmonic light transmission through sub-wavelength metallic hole arrays, and for long range surface plasmon polaritons. Plasmons are shown to coherently exist at two different times separated by much more than the plasmons lifetime. This kind of entanglement involving light and matter is expected to be useful for future processing and storing of quantum information.Comment: 4 pages, 4 figure

Neuroimaging and Analytical Methods for Studying the Pathways from Mild Cognitive Impairment to Alzheimer’s Disease: Protocol for a Rapid Systematic Review

Background Alzheimer’s disease (AD) is a neurodegenerative disorder commonly associated with deficits of cognition and changes in behavior. Mild cognitive impairment (MCI) is the prodromal stage of AD that is defined by slight cognitive decline. Not all with MCI progress to AD dementia. Thus, the accurate prediction of progression to Alzheimer’s, particularly in the stage of MCI could potentially offer developing treatments to delay or prevent the transition process. The objective of the present study is to investigate the most recent neuroimaging procedures in the domain of prediction of transition from MCI to AD dementia for clinical applications and to systematically discuss the machine learning techniques used for the prediction of MCI conversion. Methods Electronic databases including PubMed, SCOPUS, and Web of Science will be searched from January 1, 2017, to the date of search commencement to provide a rapid review of the most recent studies that have investigated the prediction of conversion from MCI to Alzheimer’s using neuroimaging modalities in randomized trial or observational studies. Two reviewers will screen full texts of included papers using predefined eligibility criteria. Studies will be included if addressed research on AD dementia and MCI, explained the results in a way that would be able to report the performance measures such as the accuracy, sensitivity, and specificity. Only studies addressed Alzheimer’s type of dementia and its early-stage MCI using neuroimaging modalities will be included. We will exclude other forms of dementia such as vascular dementia, frontotemporal dementia, and Parkinson’s disease. The risk of bias in individual studies will be appraised using an appropriate tool. If feasible, we will conduct a random effects meta-analysis. Sensitivity analyses will be conducted to explore the potential sources of heterogeneity. Discussion The information gathered in our study will establish the extent of the evidence underlying the prediction of conversion to AD dementia from its early stage and will provide a rigorous and updated synthesis of neuroimaging modalities allied with the data analysis techniques used to measure the brain changes during the conversion process

Collective Neurofeedback in an Immersive Art Environment

While human brains are specialized for complex and variable real world tasks, most neuroscience studies reduce environmental complexity, which limits the range of behaviours that can be explored. Motivated to overcome this limitation, we conducted a large-scale experiment with electroencephalography (EEG) based brain-computer interface (BCI) technology as part of an immersive multi-media science-art installation. Data from 523 participants were collected in a single night. The exploratory experiment was designed as a collective computer game where players manipulated mental states of relaxation and concentration with neurofeedback targeting modulation of relative spectral power in alpha and beta frequency ranges. Besides validating robust time-of- night effects, gender differences and distinct spectral power patterns for the two mental states, our results also show differences in neurofeedback learning outcome. The unusually large sample size allowed us to detect unprecedented speed of learning changes in the power spectrum (~ 1 min). Moreover, we found that participants' baseline brain activity predicted subsequent neurofeedback beta training, indicating state-dependent learning. Besides revealing these training effects, which are relevant for BCI applications, our results validate a novel platform engaging art and science and fostering the understanding of brains under natural conditions

Inhibitory Control in Bilinguals and Musicians: Event Related Potential (ERP) Evidence for Experience-Specific Effects.

Bilinguals and musicians exhibit behavioral advantages on tasks with high demands on executive functioning, particularly inhibitory control, but the brain mechanisms supporting these differences are unclear. Of key interest is whether these forms of experience influence cognition through similar or distinct information processing mechanisms. Here, we recorded event-related potentials (ERPs) in three groups – bilinguals, musicians, and controls – who completed a visual go-nogo task that involved the withholding of key presses to rare targets. Participants in each group achieved similar accuracy rates and responses times but the analysis of cortical responses revealed significant differences in ERP waveforms. Success in withholding a prepotent response was associated with enhanced stimulus-locked N2 and P3 wave amplitude relative to go trials. For nogo trials, there were altered timing-specific ERP differences and graded amplitude differences observed in the neural responses across groups. Specifically, musicians showed an enhanced early P2 response accompanied by reduced N2 amplitude whereas bilinguals showed increased N2 amplitude coupled with an increased late positivity wave relative to controls. These findings demonstrate that bilingualism and music training have differential effects on the brain networks supporting executive control over behavio

Assessing the photovoltaic potential of flat roofs: insights from the analysis of optimised array arrangements

PV installations on flat roofs offer a wide range of design options, which are usually neglected in urban-scale assessments as these typically assume horizontal or other fixed arrangements. In this study, we analyse the influence of common design parameters (tilt and inter-row distance) in evaluating the potential of PV arrays installed on flat roofs, using three different performance indicators. By comparing optimised arrangements to horizontal ones, we show that the latter could be misleading, unless building- and indicator-specific correction coefficients are applied.Postprint (published version

Examining Challenges to the Incorporation of End Users in the Design of Digital Health Interventions: Protocol for a Systematic Review

Background: The process of designing a digital health intervention (DHI)—also referred to as mobile health or eHealth—spans needs assessments, technical functionality and feasibility, user satisfaction, effectiveness, impact, and value. These interventions are causing a rapid evolution in the landscape of health care. Multiple studies have shown their propensity to extend both the quality and reach of interventions. However, failure to improve DHI design is linked to failed uptake and health outcomes. This dilemma is further conflicted by the colliding backdrops of the digital and health industries, both of which approach, understand, and involve end users differently in the framing of a DHI. Objective: The objective of this systematic review is to assess the challenges to incorporating end users in the design stage of digital health interventions, to identify key pain points, and to identify limitations and gaps for areas of future investigation. Methods: The PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols) checklist will be used to structure this protocol. A systematic search of the PsycINFO, PubMed (MEDLINE), Web of Science, CINAHL, Scopus, and IEEE Xplore databases will be conducted. Additionally, the PerSPEcTiF guidelines for complex interventions will be consulted. Two reviewers will independently screen the titles and abstracts of the identified references and select studies according to the eligibility criteria. Any discrepancies will then be discussed and resolved. Two reviewers will independently extract and validate data from the included studies into a standardized form and conduct quality appraisal. Results: As of February 2021, we have completed a preliminary literature search examining challenges to the incorporation of end users in the design stage of DHIs. Systematic searches, data extraction and analysis, and writing of the systematic review are expected to be completed by December 2021. Conclusions: This systematic review aims to provide an effective summary of key pain points toward incorporating end users in DHIs. Results from this review will provide an evidence base for a better approach to end user involvement in the interest of improving efficacy and uptake of DHIs

Polyproline is a minimal antifreeze protein mimetic and enhances the cryopreservation of cell monolayers

Tissue engineering, gene therapy, drug screening and emerging regenerative medicine therapies are fundamentally reliant on high-quality adherent cell culture, but current methods to cryopreserve cells in this format can give low cell yields and requires large volumes of solvent 'antifreezes'. Herein we report polyproline is a minimum (bio)synthetic mimic of antifreeze proteins, which is accessible by solution, solid phase and recombinant methods. We demonstrate that polyproline has ice recrystallization inhibition activity linked to its amphipathic helix and that it enhances the DMSO- cryopreservation of adherent cell lines. Polyproline may be a versatile additive in the emerging field of macromolecular cryoprotectants

Moderate-Intensity Physical Activity, Music and Art Activities Preserved Cognitive Health in Older Adults: An Argument for Social Prescribing Solution

Introduction: Rates of dementia are projected to increase over the coming years as global populations age. Without a treatment to slow the progression of dementia, many health policies are focusing on preventing dementia by slowing the rate of cognitive decline with age. However, it is unclear which lifestyle changes in old age meaningfully reduce the rate of cognitive decline associated with aging. Objectives: Use existing, multi-year longitudinal health data to determine if engagement in a variety of different lifestyle activities can slow the rate of cognitive decline as older adults age. Method: Data from the English Longitudinal Study of Aging was analyzed using a quasi-experimental, efficient matched-pair design inspired by the clinical trial methodology. Changes in short-term memory scores were assessed over a multi-year interval for groups who undertook one of 11 different lifestyle activities, compared to control groups matched across confounding socioeconomic and lifestyle factors. Results: Two factors, moderate-intensity physical activity and learning activities, resulted in significant positive impact on cognitive function. Conclusion: Our analysis brings cognitive benefit arguments in favor of two lifestyle activities, moderate-intensity physical activity and learning activities, while rejecting other factors advanced by the literature such as vigorous-intensity physical activity. Those findings justify and encourage the development of new lifestyle health programs by health authorities and bring forward the new health system solution, social prescribing