Natural and synthetic polymer-based hybrid materials for tissue regeneration

The world’s population is aging and cases of debilitating degenerative diseases are increasing. Bone is the second most transplanted tissue after blood but natural bone grafts are in short supply. Bioglass, which is a particular composition of bioactive glass, stimulates more bone repair than other synthetic bone grafts. However, it is brittle so cannot be used in cyclically loaded sites. A promising solution is the use of hybrid materials that can potentially combine the toughness of polymers with the stiffness and bioactivity of the glass through interpenetrating inorganic-organic networks. Hybrids have the unique feature of tuneable mechanical properties and degradation rates. In this thesis, two very different polymers were investigated as the organic component of hybrids; chitosan and poly(2-hydroxyethyl methacrylate-co-(3-trimethoxysilane)propyl methacrylate). The natural polymer chitosan was incorporated into the silica sol-gel process to produce hybrids and scaffolds were fabricated using freeze drying and foaming techniques. The chemical, morphological, mechanical and degradation properties of the scaffolds were studied. In order to covalently bond the organic and inorganic components, the chitosan was functionalised with an alkoxysilane crosslinker, 3-glycidoxypropyl trimethoxysilane. Using NMR and FTIR, the functionalisation reaction and side-reactions were characterised, discovering that the reaction was only 20% efficient at all pH values. To avoid the inefficient functionalisation reactions and concerns over the reproducibility of natural polymers, the synthetic co-polymer poly(2-hydroxyethyl methacrylate-co-(3-trimethoxysilane)propyl methacrylate) was synthesised by controlled polymerisation techniques (ATRP and ARGET ATRP) and typical free radical polymerisation (FRP). ATRP gave good control over molecular weight distributions, but the copper catalyst had serious implications on the chemical and architectural structure of the polymers. An NMR kinetics study was used to identify alternative polymerisation routes that could avoid the problems associated with the copper catalyst. The polymers were introduced into the sol-gel process to produce entirely synthetic hybrids with non-brittle (tough) behaviour and dissolution rates controlled by the polymer composition. The hybrids also exhibited hydroxyapatite precipitation in simulated body fluid, indicative of potential bioactivity in vivo. Hence, the aim of producing non-brittle, bioactive materials with controllable degradation rates was achieved.Open Acces

Do we know what we're simulating?:information loss on transferring unconscious perceptual simulation to conscious imagery

Perceptual simulations are unconscious and automatic, whereas perceptual imagery is conscious and deliberate, but it is unclear how easily one can transfer perceptual information from unconscious to conscious awareness. We investigated whether it is possible to be aware of what one is mentally representing; that is, whether it is possible to consciously examine the contents of a perceptual simulation without information being lost. Studies 1 and 2 found that people cannot accurately evaluate the perceptual content of a representation unless attention is explicitly drawn to each modality individually. In particular, when asked to consider sensory experience as a whole, modality-specific auditory, gustatory, and haptic information is neglected, and olfactory and visual information distorted. Moreover, information loss is greatest for perceptually complex, multimodal simulations. Study 3 examined if such information loss leads to behavioral consequences by examining performance during lexical decision, a task whose semantic effects emerge from automatic access to the full potential of unconscious perceptual simulation. Results showed that modality-specific perceptual strength consistently outperformed modality-general sensory experience ratings in predicting latency and accuracy, which confirms that the effects of Studies 1 and 2 are indeed due to information being lost in the transfer to conscious awareness. These findings suggest that people indeed have difficulty in transferring perceptual information from unconscious simulation to conscious imagery. People cannot be aware of the full contents of a perceptual simulation because the act of bringing it to awareness leads to systematic loss of information

Embodied Conceptual Combination

Conceptual combination research investigates the processes involved in creating new meaning from old referents. It is therefore essential that embodied theories of cognition are able to explain this constructive ability and predict the resultant behavior. However, by failing to take an embodied or grounded view of the conceptual system, existing theories of conceptual combination cannot account for the role of perceptual, motor, and affective information in conceptual combination. In the present paper, we propose the embodied conceptual combination (ECCo) model to address this oversight. In ECCo, conceptual combination is the result of the interaction of the linguistic and simulation systems, such that linguistic distributional information guides or facilitates the combination process, but the new concept is fundamentally a situated, simulated entity. So, for example, a cactus beetle is represented as a multimodal simulation that includes visual (e.g., the shiny appearance of a beetle) and haptic (e.g., the prickliness of the cactus) information, all situated in the broader location of a desert environment under a hot sun, and with (at least for some people) an element of creepy-crawly revulsion. The ECCo theory differentiates interpretations according to whether the constituent concepts are destructively, or non-destructively, combined in the situated simulation. We compare ECCo to other theories of conceptual combination, and discuss how it accounts for classic effects in the literature

Therapists\u27 use of the graded repetitive arm supplementary program (GRASP) intervention: A practice implementation survey study

The aims of this study were: (1) to explore the extent of practice implementation of GRASP in the United Kingdom; (2) using an implementation framework, to explore UK therapists\u27 opinions of implementing GRASP; and (3) if GRASP is found to be used in the United Kingdom, to investigate differences in opinions between therapists who are using GRASP in practice and those who are not

What have labels ever done for us?:The linguistic shortcut in conceptual processing

How does language affect cognition? Is it important that most of our concepts come with linguistic labels, such as car or number? The statistical distributions of how such labels co-occur in language offers a rich medium of associative information that can support conceptual processing in a number of ways. In this article, I argue that the role of language in conceptual processing goes far beyond mere support, and that language is as fundamental and intrinsic a part of conceptual processing as sensorimotor-affective simulations. In particular, because linguistic association tends to be computationally cheaper than simulation (i.e. faster, less effortful, but still information-rich), it enables an heuristic mechanism that can provide adequate conceptual representation without the need to develop a detailed simulation. I review the evidence for this key mechanism – the linguistic shortcut – and propose that it allows labels to sometimes carry the burden of conceptual processing by acting in place of simulated referent meanings, according to context, available resources, and processing goals

Prescribing upper limb exercises after stroke: A survey of current UK therapy practice.

Objective: To investigate the current practice of physiotherapists and occupational therapists in prescribing upper limb exercises to people after stroke and to explore differences between professions and work settings. Design: A cross-sectional survey design. Participants: Occupational therapists and physiotherapists working in UK stroke rehabilitation. Results: The survey's response rate was 21.0% (n = 322); with 295 valid responses. Almost two thirds of therapists (64.7%, n = 191) agreed that they always prescribe upper limb exercises to a person with stroke if they can actively elevate their scapula and have grade 1 finger/wrist extension. Most therapists (98.6%, n = 278) prescribed exercises to be completed outside of therapy time, with exercises verbally communicated to family. Standardised upper limb specific outcome measures were used to evaluate the prescribed exercises by 21.9% (n = 62) of therapists. Differences were found between professions and across work settings. Conclusion: The majority of prescribed upper limb exercises were of low intensity (range of motion or stretching exercises) rather than repetitive practice or strengthening exercises. The use of standardised outcome measures was low. Progression of exercises and the provision of written instructions on discharge occur less frequently in inpatient settings than outpatient and community settings

The Lancaster Sensorimotor Norms : Multidimensional measures of Perceptual and Action Strength for 40,000 English words

Sensorimotor information plays a fundamental role in cognition. However, the existing materials that measure the sensorimotor basis of word meanings and concepts have been restricted in terms of their sample size and breadth of sensorimotor experience. Here we present norms of sensorimotor strength for 39,707 concepts across six perceptual modalities (touch, hearing, smell, taste, vision, and interoception) and five action effectors (mouth/throat, hand/arm, foot/leg, head excluding mouth/throat, and torso), gathered from a total of 3,500 individual participants using Amazon’s Mechanical Turk platform. The Lancaster Sensorimotor Norms are unique and innovative in a number of respects: They represent the largest-ever set of semantic norms for English, at 40,000 words × 11 dimensions (plus several informative cross-dimensional variables), they extend perceptual strength norming to the new modality of interoception, and they include the first norming of action strength across separate bodily effectors. In the first study, we describe the data collection procedures, provide summary descriptives of the dataset, and interpret the relations observed between sensorimotor dimensions. We then report two further studies, in which we (1) extracted an optimal single-variable composite of the 11-dimension sensorimotor profile (Minkowski 3 strength) and (2) demonstrated the utility of both perceptual and action strength in facilitating lexical decision times and accuracy in two separate datasets. These norms provide a valuable resource to researchers in diverse areas, including psycholinguistics, grounded cognition, cognitive semantics, knowledge representation, machine learning, and big-data approaches to the analysis of language and conceptual representations. The data are accessible via the Open Science Framework (http://osf.io/7emr6/) and an interactive web application (https://www.lancaster.ac.uk/psychology/lsnorms/)