285 research outputs found

    The Ultimate Fate of Supercooled Liquids

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    In recent years it has become widely accepted that a dynamical length scale {\xi}_{\alpha} plays an important role in supercooled liquids near the glass transition. We examine the implications of the interplay between the growing {\xi}_{\alpha} and the size of the crystal nucleus, {\xi}_M, which shrinks on cooling. We argue that at low temperatures where {\xi}_{\alpha} > {\xi}_M a new crystallization mechanism emerges enabling rapid development of a large scale web of sparsely connected crystallinity. Though we predict this web percolates the system at too low a temperature to be easily seen in the laboratory, there are noticeable residual effects near the glass transition that can account for several previously observed unexplained phenomena of deeply supercooled liquids including Fischer clusters, and anomalous crystal growth near T_g

    An Intelligent Decision Support System for the Detection of Meat Spoilage using Multispectral Images

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    In food industry, quality and safety are considered important issues worldwide that are directly related to health and social progress. The use of vision technology for quality testing of food production has the obvious advantage of being able to continuously monitor a production using non-destructive methods, thus increasing the quality and minimizing cost. The performance of an intelligent decision support system has been evaluated in monitoring the spoilage of minced beef stored either aerobically or under modified atmosphere packaging, at different storage temperatures (0, 5, 10, and 15 °C) utilising multispectral imaging information. This paper utilises a neuro-fuzzy model which incorporates a clustering pre-processing stage for the definition of fuzzy rules, while its final fuzzy rule base is determined by competitive learning. Initially, meat samples are classified according to their storage conditions, while identification models are then utilised for the prediction of the Total Viable Counts of bacteria. The innovation of the proposed approach is further extended to the identification of the temperature used for storage, utilizing only imaging spectral information. Results indicated that spectral information in combination with the proposed modelling scheme could be considered as an alternative methodology for the accurate evaluation of meat spoilage

    What's wrong with the murals at the Mogao Grottoes : a near-infrared hyperspectral imaging method

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    Although a significant amount of work has been performed to preserve the ancient murals in the Mogao Grottoes by Dunhuang Cultural Research, non-contact methods need to be developed to effectively evaluate the degree of flaking of the murals. In this study, we propose to evaluate the flaking by automatically analyzing hyperspectral images that were scanned at the site. Murals with various degrees of flaking were scanned in the 126th cave using a near-infrared (NIR) hyperspectral camera with a spectral range of approximately 900 to 1700 nm. The regions of interest (ROIs) of the murals were manually labeled and grouped into four levels: normal, slight, moderate, and severe. The average spectral data from each ROI and its group label were used to train our classification model. To predict the degree of flaking, we adopted four algorithms: deep belief networks (DBNs), partial least squares regression (PLSR), principal component analysis with a support vector machine (PCA + SVM) and principal component analysis with an artificial neural network (PCA + ANN). The experimental results show the effectiveness of our method. In particular, better results are obtained using DBNs when the training data contain a significant amount of striping noise

    Development of a rating scale for objective assessment of performance in laparoscopic appendicectomy surgery

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    First published: 26 March 2022Backgrounds: Laparoscopic appendicectomy (LA) is the most common index procedure for junior surgical trainees. Despite the shift towards competency-based training, there is no method of quantitatively assessing performance during LA. This study aimed to obtain expert consensus regarding the items required to create a LA Rating Scale (LARS). Methods: A list of steps required for LA surgery, as well as descriptors of “poor”, “average” and “excellent” performance for each of these steps were created for potential inclusion into an objective assessment tool for LA surgery. Using a Delphi method, 20 experts from multiple institutions rated on a Likert scale from 1 to 5 the suitability of these steps and descriptors of performance. Responses were obtained until consensus (Cronbach’s α > 0.8) was achieved. Results: Fifteen experts participated in the study. Consensus was achieved for all items during the first iteration of the Delphi with a Cronbach’s α of 0.96. The Cronbach’s α for the steps was 0.87 and 0.92 for the descriptors of performance. Steps and descriptors of performance that >80% of experts rated as ≥4 were used to create the final LARS tool. Conclusion: Multi-institutional expert consensus was obtained regarding the steps and, for the first time, descriptors of performance for LA, demonstrating their face and content validity, as well as generalisability. Subsequently, the LARS tool was created that can be used to quantitatively assess intra-operative performance. This instrument can be used to identify weaknesses in performance and facilitate deliberate practice, thus shifting training in LA to a competency-based approach.Pramudith Sirimanna, Stephen Boyce, Prashanth Gunanayagam, Marc A. Gladman, and Vasi Naganatha

    Health and Functional Status of Adults with Intellectual Disability Referred to the Specialist Health Care Setting: A Five-Year Experience

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    Aims and Method. The Developmental Disability Database in the Department of Rehabilitation Medicine at a metropolitan hospital was audited for observations on adults with Intellectual Disability living in the local region (total population 180,000) who were seen in an identified multidisciplinary specialist clinic, during 2006–2010. Results. There were 162 people (representing half the known number of adults with Intellectual Disability living in the region): 77 females, 85 males, age range 16–86 years. The most common complex disabilities referred to the specialists in this clinic were epilepsy (52%), challenging or changing behavior (42%) and movement disorders (34%). Early onset dementia was a feature of the group (7%). The prevalence of prescription of medications for gastro-oesophageal reflux was high (36%) and similar to the numbers of people taking psychotropic medications. The rates of chronic cardiovascular disease (2%), chronic respiratory disease (10%) and generalised arthritis (11%) were low overall, but did rise with increasing age. Conclusions. Complex neurological disabilities are common, and chronic medical illnesses are uncommon in adults with Intellectual Disability referred to specialist clinicians in this region. A combined, coordinated, multidisciplinary clinic model addresses some of the barriers experienced by adults with Intellectual Disability in the secondary health system

    Mixed Evidence of an Association between Self-Rated Hearing Difficulties and Falls: Prospective Analysis of Two Longitudinal Studies

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    Introduction: This study aimed to assess the extent to which a single item of self-reported hearing difficulties is associated with future risk of falling among community-dwelling older adults. Methods: We used data from two Australian population-based cohorts: three waves from the PATH Through Life study (PATH; n = 2,048, 51% men, age 66.5 ± 1.5 SD years) and three waves from the Concord Health and Ageing in Men Project (CHAMP; n = 1,448, 100% men with mean age 77.3 ± 5.3 SD years). Hearing difficulties were recorded on a four-point ordinal scale in PATH and on a dichotomous scale in CHAMP. The number of falls in the past 12 months was reported at each wave in both studies. In CHAMP, incident falls were also ascertained by triannual telephone call cycles for up to four years. Multivariable-adjusted random intercept negative binomial regression models were used to estimate the association between self-reported hearing difficulties and number of falls reported at the following wave or 4-monthly follow-ups. Results: In PATH, self-reported hearing difficulties were associated with a higher rate of falls at follow-up (incidence rate ratio = 1.15, 95% CI = 1.03-1.27 per a one-level increase in self-reported hearing difficulties), after adjusting for sociodemographic characteristics, health behaviours, physical functioning, balance, mental health, medical conditions, and medications. There were no significant associations between hearing difficulties and the rate of falls based on either repeated survey or 4-monthly follow-ups in CHAMP. Conclusion: Though we find mixed results, findings from PATH data indicate an ordinal measure of self-reported hearing loss may be predictive of falls incidence in young-old adults. However, the null findings in the male-only CHAMP preclude firm conclusions of a link between hearing loss and falls risk

    Allosteric Communication in the Multifunctional and Redox NQO1 Protein Studied by Cavity-Making Mutations

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    Allosterism is a common phenomenon in protein biochemistry that allows rapid regulation of protein stability; dynamics and function. However, the mechanisms by which allosterism occurs (by mutations or post-translational modifications (PTMs)) may be complex, particularly due to long-range propagation of the perturbation across protein structures. In this work, we have investigated allosteric communication in the multifunctional, cancer-related and antioxidant protein NQO1 by mutating several fully buried leucine residues (L7, L10 and L30) to smaller residues (V, A and G) at sites in the N-terminal domain. In almost all cases, mutated residues were not close to the FAD or the active site. Mutations L\u2192G strongly compromised conformational stability and solubility, and L30A and L30V also notably decreased solubility. The mutation L10A, closer to the FAD binding site, severely decreased FAD binding affinity ( 4820 fold vs. WT) through long-range and context-dependent effects. Using a combination of experimental and computational analyses, we show that most of the effects are found in the apo state of the protein, in contrast to other common polymorphisms and PTMs previously characterized in NQO1. The integrated study presented here is a first step towards a detailed structural-functional mapping of the mutational landscape of NQO1, a multifunctional and redox signaling protein of high biomedical relevance

    KineticDB: a database of protein folding kinetics

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    We propose here KineticDB, a systematically compiled database of protein folding kinetics, which contains about 90 unique proteins. The main goal of the KineticDB is to provide users with a diverse set of protein folding rates determined experimentally. The search for determinants of protein folding is still in progress, aimed at obtaining a new understanding of the folding process. Comparison with experimental protein folding rates has been the main tool for validation of both theoretical models and empirical relationships during the last 10 years. It is, therefore, necessary to provide a researcher with as much data as possible in a simple and easy-to-use way. At present, the KineticDB contains the results of folding kinetics measurements of single-domain proteins and separate protein domains as well as short peptides without disulfide bonds. It includes data on about 90 unique proteins and many mutants that have been systematically accumulated over the last 10 years and is the largest collection of protein folding kinetic data presented as a database. The KineticDB is available at http://kineticdb.protres.ru/db/index.pl

    Actively crosslinked microtubule networks: mechanics, dynamics and filament sliding

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    Cytoskeletal networks are foundational examples of active matter and central to self-organized structures in the cell. In vivo, these networks are active and heavily crosslinked. Relating their large-scale dynamics to properties of their constituents remains an unsolved problem. Here we study an in vitro system made from microtubules and XCTK2 kinesin motors, which forms an aligned and active gel. Using photobleaching we demonstrate that the gel's aligned microtubules, driven by motors, continually slide past each other at a speed independent of the local polarity. This phenomenon is also observed, and remains unexplained, in spindles. We derive a general framework for coarse graining microtubule gels crosslinked by molecular motors from microscopic considerations. Using the microtubule-microtubule coupling, and force-velocity relationship for kinesin, this theory naturally explains the experimental results: motors generate an active strain-rate in regions of changing polarity, which allows microtubules of opposite polarities to slide past each other without stressing the material

    Care of older people and people requiring palliative care with COVID-19: guidance from the Australian National COVID-19 Clinical Evidence Taskforce.

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    INTRODUCTION: Older people living with frailty and/or cognitive impairment who have coronavirus disease 2019 (COVID-19) experience higher rates of critical illness. There are also people who become critically ill with COVID-19 for whom a decision is made to take a palliative approach to their care. The need for clinical guidance in these two populations resulted in the formation of the Care of Older People and Palliative Care Panel of the National COVID-19 Clinical Evidence Taskforce in June 2020. This specialist panel consists of nursing, medical, pharmacy and allied health experts in geriatrics and palliative care from across Australia. MAIN RECOMMENDATIONS: The panel was tasked with developing two clinical flow charts for the management of people with COVID-19 who are i) older and living with frailty and/or cognitive impairment, and ii) receiving palliative care for COVID-19 or other underlying illnesses. The flow charts focus on goals of care, communication, medication management, escalation of care, active disease-directed care, and managing symptoms such as delirium, anxiety, agitation, breathlessness or cough. The Taskforce also developed living guideline recommendations for the care of adults with COVID-19, including a commentary to discuss special considerations when caring for older people and those requiring palliative care. CHANGES IN MANAGEMENT AS RESULT OF THE GUIDELINE: The practice points in the flow charts emphasise quality clinical care, with a focus on addressing the most important challenges when caring for older individuals and people with COVID-19 requiring palliative care. The adult recommendations contain additional considerations for the care of older people and those requiring palliative care
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