186 research outputs found

    Social Support and Survival Strategies of Older African American Grandmother Caregivers

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    The effects of caring for grandchildren on grandparents’ emotional and physical well-being have become a significant area of focus in behavioral and medical research. Research suggests that African American grandmothers may experience increased mental and physical health challenges due to their caregiving stressors. To buffer the adverse influence of stress, caregivers often rely on informal social support from family and/or community members. In this study we explored older, African American caregivers’ management of their emotional well-being within the context and circumstances of available to minimal social support from family and community. During an 18-month period, seven caregiving grandmothers participated in three face-to-face, audiotaped, semi-structured interviews; eco-map and genogram data was included to understand the contextual complexities of caregivers’ social support and their strategies for survival. Using constant comparative analysis, six interrelated themes revealed grandmothers operated along a continuum of reliable to unreliable social support. In the context of these varying ranges of social support, four sub-themes depicting their survival strategies were identified: being strong, self-sacrificing, receiving help and self-compassion. Utilization of each survival strategy was dependent on grandmothers’ perception of where they fell on the continuum of reliable to unreliable social support. Grandmothers who engaged in being strong and self-sacrificing engaged in stress-related health behaviors, such as emotional eating, smoking nicotine, disruptive sleep patterns and postponement of self-care. We offer specific practice recommendations for addressing the emotional and physical health needs of grandmother caregivers

    Enhancement of seawater corrosion resistance in copper using acetone-derived graphene coating

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    We show that acetone-derived graphene coating can effectively enhance the corrosion efficiency of copper (Cu) in a seawater environment (0.5-0.6 M (???3.0-3.5%) sodium chloride). By applying a drop of acetone (???20 ??l cm-2) on Cu surfaces, rapid thermal annealing allows the facile and rapid synthesis of graphene films on Cu surfaces with a monolayer coverage of almost close to ???100%. Under optimal growth conditions, acetone-derived graphene is found to have a relatively high crystallinity, comparable to common graphene grown by chemical vapor deposition. The resulting graphene-coated Cu surface exhibits 37.5 times higher corrosion resistance as compared to that of mechanically polished Cu. Further, investigation on the role of graphene coating on Cu surfaces suggests that the outstanding corrosion inhibition efficiency (IE) of 97.4% is obtained by protecting the underlying Cu against the penetration of both dissolved oxygen and chlorine ions, thanks to the closely spaced atomic structure of the graphene sheets. The increase of graphene coating thickness results in the enhancement of the overall corrosion IE up to ???99%, which can be attributed to the effective blocking of the ionic diffusion process via grain boundaries. Overall, our results suggest that the acetone-derived graphene film can effectively serve as a corrosion-inhibiting coating in the seawater level and that it may have a promising role to play for potential offshore coating.close0

    Computational and Experimental Evaluation of Peroxide Oxidants for Amine-Peroxide Redox Polymerization

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    Amine–peroxide redox polymerization (APRP) is the prevalent method for producing radical-based polymers in the many industrial and medical applications where light or heat activation is impractical. We recently developed a detailed description of the APRP initiation process through a combined computational and experimental effort to show that APRP proceeds through SN2 attack by the amine on the peroxide, followed by the rate-determining homolysis of the resulting intermediate. Using this new mechanistic understanding, a variety of peroxides were computationally predicted to initiate APRP with fast kinetics. In particular, the rate of APRP initiation can be improved by radical and anion stabilization through increased π-electron conjugation or by increasing the electrophilicity of the peroxy bond through the addition of electron-withdrawing groups. On the other hand, the addition of electron-donating groups lowered the initiation rate. These design principles enabled the computational prediction of several new peroxides that exhibited improved initiation rates over the commonly used benzoyl peroxide. For example, the addition of nitro groups (NO₂) to the para positions of benzoyl peroxide resulted in a theoretical radical generation rate of 1.9 × 10⁻âč s⁻Âč, which is ∌150 times faster than the 1.3 × 10⁻ÂčÂč s⁻Âč radical generation rate observed with unsubstituted benzoyl peroxide. These accelerated kinetics enabled the development of a redox-based direct-writing process that exploited the extremely rapid reactivity of an optimized redox pair with a custom inkjet printer, capable of printing custom shapes from polymerizing resins without heat or light. Furthermore, the application of more rapid APRP kinetics could enable the acceleration of existing industrial processes, make new industrial manufacturing methods possible, and improve APRP compatibility with biomedical applications through reduced initiator concentrations that still produce rapid polymerization rates

    Biodiversity of the Colorado State University lands

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    Prepared for: Colorado State University Facilities Management.June 2022.Includes bibliographical references.During the academic year of 2021-2022, the Colorado Natural Heritage Program (CNHP) was contracted by CSU Facilities Management to complete a biodiversity survey of the CSU lands. This assessment will be used by Facilities Management to self-report on the Biodiversity component of the Operations category in the STARS (Sustainability, Tracking, Assessment, & Ratings System) report. This report assesses endangered and vulnerable species (including migratory species) on CSU-owned and managed lands and areas of biodiversity importance on CSU-owned and managed lands. An additional aim of this project was to include students in the geospatial analysis, research, and field data collection efforts, thereby lowering project costs and providing mentorship and experience to the students. Biodiversity was assessed through a geospatial environmental review of the properties which includes documented and potential occurrences of regulatory species and other species of concern within the property and a 1-mile buffer, assessment of the conservation areas adjacent to the property and within a buffer, and the diversity and acreage of wetlands and other ecosystem types. The conservation value of each property, based on a Return-on-Investment report, is presented. Geospatial data area used to evaluate climate resiliency and landscape disturbance. Further research into species on the largest and most well-studied properties is presented, along with results of field work. Colorado State University holds 32 individual properties, spanning 14 counties across Colorado, covering a total of 3,943 hectares. Properties held by CSU had 303 documented occurrences of regulatory species and other species of concern within 1 mile returned in the environmental review; additionally, potential habitat was returned for another 2210 regulatory and other species of concern from a combination of range maps, general precision CNHP element occurrence records, and models. Through the many metrics of biodiversity assessed, several properties stood out; these included the Eastern Colorado Research Center, the Mountain Campus, Foothills, Horsetooth, and the Environmental Learning Center. At the Eastern Colorado Research Center, a combination of research field work recorded 187 species as visual observations and/or within a modeled area. At the Mountain Campus, student research and field work recorded a total of 1,044 species as visual observations and/or within a modeled area, with 754 Animalia species, 273 Plantae species and 17 Fungi species. Along with providing information on the biodiversity on the CSU lands, this project provided educational value to CSU students and facilitated the creation of a storymap to showcase the biodiversity of CSU lands to the public and stakeholders. The biodiversity assessment suggests several actions which could be taken to protect, enhance, or restore the biodiversity found on CSU lands and identified properties with possible conservation gains through enhancement and restoration.June 2022

    Chemorheology of photopolymerizable acrylates using a modified Boltzmann sigmoidal model

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    Experiments were conducted to evaluate the influence of ambient photoconversion on rheology for a range of photopolymerizable urethane dimethacrylate (UDMA) resins containing varying amounts of three comonomers including 1,6 hexane diol-dimethacrylate (HDDMA), an alkoxylated cyclohexane dimethanol diacrylate monomer (CD-582), and hydroxyethyl methacrylate (HEMA). Experiments were performed both as a function of composition and time-dependent dose varying the intensity using a photorheometer. A semilog-based sigmoidal model allowed the determination of four physical model parameters to define the relationship between reaction kinetics and its dynamic influence on viscosity. We have observed induction times and viscosity changes associated with the model that shows a trend in reaction kinetics in the following order from most to least reactive: UDMA > CD582 > HDDMA > HEMA. With increasing amounts of reactive diluent included in the formulation, the kinetics of reaction was more sluggish. The value of this sigmoidal model is that it could help define formulation and process conditions most likely to control crosslinking to maximize dimensional stability or other thermophysical properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2319–2325, 2008Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61230/1/21563_ftp.pd

    Origin of micro-scale heterogeneity in polymerisation of photo-activated resin composites

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    Photo-activated resin composites are widely used in industry and medicine. Despite extensive chemical characterisation, the micro-scale pattern of resin matrix reactive group conversion between filler particles is not fully understood. Using an advanced synchrotron-based wide-field IR imaging system and state-of-the-art Mie scattering corrections, we observe how the presence of monodispersed silica filler particles in a methacrylate based resin reduces local conversion and chemical bond strain in the polymer phase. Here we show that heterogeneity originates from a lower converted and reduced bond strain boundary layer encapsulating each particle, whilst at larger inter-particulate distances light attenuation and monomer mobility predominantly influence conversion. Increased conversion corresponds to greater bond strain, however, strain generation appears sensitive to differences in conversion rate and implies subtle distinctions in the final polymer structure. We expect these findings to inform current predictive models of mechanical behaviour in polymer-composite materials, particularly at the resin-filler interface

    Zinc-modified nanopolymers improve the quality of resin-dentin bonded interfaces

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    Introduction: Demineralized collagen fibers at the hybrid layer are susceptible to degradation. Remineralization may aid to improve bond longevity. Objectives: The aim of the present study was to infiltrate zinc and calcium-loaded polymeric nanoparticles into demineralized dentin to facilitate hybrid layer remineralization. Materials and methods: Zinc or calcium-loaded polymeric nanoparticles were infiltrated into etched dentin, and Single Bond Adhesive was applied. Bond strength was tested after 24 h and 6 months storage. Nanomechanical properties, dyeassisted confocal laser microscopy, and Masson’s trichrome staining evaluation were performed to assess for the hybrid layer morphology, permeability, and remineralization ability after 24 h and 3 months. Data were analyzed by ANOVA and Student–Newman–Keuls multiple comparisons tests (p < 0.05). Results: Immediate bond strength was not affected by nanoparticles infiltration (25 to 30 MPa), while after 6 months, bond strengths were maintained (22 to 24 MPa). After 3 months, permeability occurred only in specimens in which nanoparticles were not infiltrated. Dentin remineralization, at the bottom of the hybrid layer, was observed in all groups. After microscopy analysis, zinc-loaded nanoparticles were shown to facilitate calcium deposition throughout the entire hybrid layer. Young’s modulus at the hybrid layer increased from 2.09 to 3.25 GPa after 3 months, in specimens with zinc nanoparticles; meanwhile, these values were reduced from 1.66 to 0.49 GPa, in the control group. Conclusion: Infiltration of polymeric nanoparticles into demineralized dentin increased long-term bond strengths. Zinc-loaded nanoparticles facilitate dentin remineralization within the complete resin–dentin interface. Clinical relevance: Resin–dentin bond longevity and dentin remineralization at the hybrid layer were facilitated by zincloaded nanoparticles.This work was supported by a grant, MINECO/FEDER MAT2014-52036-P
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