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

'Good Morning Fitfam': Top posts, hashtags and gender display on Instagram

Social networking sites are important platforms for visual self-presentation online. This article investigates how content producers present their gender identities on the social networking site, Instagram. We draw upon and develop Goffman’s analytic framework to understand the self-presentation techniques and styles users employ online. Conducting a visual content analysis of clean eating–related top posts, we examine how users deploy clean eating hashtags and how the architecture of Instagram constrains and enables certain identities around shared lifestyles and commercial interests. Our findings reveal the symbolic significance of hashtags for group membership and the degree to which gender identities on Instagram are configured around platform interfaces

UNBOUND

UNBOUND showcases the graduating class from the fashion design school at Fanshawe College.https://first.fanshawec.ca/famd_design_fashiondesign_unbound/1007/thumbnail.jp

Structural basis of high-order oligomerization of the cullin-3 adaptor SPOP.

Protein ubiquitination in eukaryotic cells is mediated by diverse E3 ligase enzymes that each target specific substrates. The cullin E3 ligase complexes are the most abundant class of E3 ligases; they contain various cullin components that serve as scaffolds for interaction with substrate-recruiting adaptor proteins. SPOP is a BTB-domain adaptor of the cullin-3 E3 ligase complexes; it selectively recruits substrates via its N-terminal MATH domain, whereas its BTB domain mediates dimerization and interactions with cullin-3. It has recently been recognized that the high-order oligomerization of SPOP enhances the ubiquitination of substrates. Here, a dimerization interface in the SPOP C-terminus is identified and it is shown that the dimerization interfaces of the BTB domain and of the C-terminus act independently and in tandem to generate high-order SPOP oligomers. The crystal structure of the dimeric SPOP C-terminal domain is reported at 1.5 Å resolution and it is shown that Tyr353 plays a critical role in high-order oligomerization. A model of the high-order SPOP oligomer is presented that depicts a helical organization that could enhance the efficiency of substrate ubiquitination

Violent masculinities: Gendered dynamics of policing in Rio de Janeiro

Historically, policing in Rio de Janeiro has been shaped by the equation of racialized violence and masculinity. Attempts to reform the police have paradoxically drawn on forms of male violence that are centered on the rational and professional use of force and on “softer” practices, such as dialogue and collaboration, symbolically coded as feminine. The failure of police reform reflects the cultural salience of understandings of masculinity centered around violence within the police, historical patterns of policing in Rio, and political actors’ strategic cultivation of male violence. Through Rio de Janeiro's failed attempt at police reform, we theorize the relation between racialized state violence, authoritarian political projects, and transgressive forms of male violence, arguing that an important appeal of authoritarianism lies in its promise to carve out a space for performing what we call wild masculinity. [masculinity, race, police, violence, gender, politics, favela, Rio de Janeiro, Brazil]publishedVersio

Emotion processing and psychogenic non-epileptic seizures: A cross-sectional comparison of patients and healthy controls

Purpose This exploratory study aimed to examine emotion-processing styles in patients with psychogenic non-epileptic seizures (PNES), compared to healthy individuals, and to explore associations of emotion processing with other psychological measures and seizure frequency, using the new Emotional Processing Scale (EPS-25), which had not previously been used in this patient group. Methods Fifty consecutive patients with PNES referred for psychotherapy completed a set of self-report questionnaires, including the Emotional Processing Scale (EPS-25), Clinical Outcome in Routine Evaluation (CORE-10), Short Form-36 (SF-36), Patient Health Questionnaire (PHQ-15), and Brief Illness Perception Questionnaire (BIPQ). Responses on the EPS-25 were compared to data from 224 healthy controls. Results Patients with PNES had greater emotion processing deficits across all dimensions of the EPS-25 than healthy individuals (suppression/unprocessed emotion/unregulated emotion/avoidance/impoverished emotional experience). Impaired emotion processing was highly correlated with psychological distress, more frequent and severe somatic symptoms, and a more threatening understanding of the symptoms. Emotion processing problems were also associated with reduced health-related quality of life on the mental health (but not the physical health) component of the SF-36. The unregulated emotions sub-scale of the EPS was associated with lower seizure frequency. Conclusion The results showed clear impairments of emotion processing in patients with PNES compared to healthy individuals, which were associated with greater psychological distress and reduced mental health functioning. These findings seem to support the face validity of the EPS-25 as a measure for PNES patients and its potential as a tool to assess the effectiveness of psychological interventions