153 research outputs found

    Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

    Get PDF
    Sunscreen formulations have been developed to provide an artificial protective barrier against the deleterious effects of overexposure to ultraviolet (UV) radiation in humans. Ultrafast pump-probe spectroscopy techniques have been an invaluable tool in recent years for determining the photochemistry of active ingredients in sunscreen formulations, predominantly UV filters, in both the gas- and solution-phases. These measurements have enabled the elucidation of molecular relaxation pathways and photoprotection mechanisms, which are in turn insightful for assessing a filter's photostability and suitability for sunscreen use. In this review, we discuss the benefits of a bottom-up approach: the progression from the study of UV filters for sunscreens in vacuum, away from the influences of any solvent; in solution, to investigate the relaxation pathways of potential sunscreen filters in closer to real-life conditions, whilst exploring the merits of selective functionalisation to improve their characteristics; and beyond, to current advances that are mimicking the application of sunscreen formulations to the surface of the skin

    Synthesis and characterisation of novel composite sunscreens containing both avobenzone and octocrylene motifs †

    Get PDF
    Avobenzone and octocrylene are popular sunscreen active ingredients. Experiments that probe the stability of avobenzone in binary mixtures with octocrylene are presented, together with the synthesis of a class of novel composite sunscreens that were designed by covalently linking avobenzone and octocrylene groups. Spectroscopy, both steady-state and time-resolved, of the fused molecules was performed to investigate the stability of the new molecules and their potential function as ultraviolet filters. Computational results are detailed for truncated versions of a subset of the molecules to reveal the energy states underlying the absorption processes of this new class of sunscreen. The results indicate that the combination of elements of the two sunscreen molecules into one molecule creates a derivative with good stability to UV light in ethanol and in which the main degradation pathway of the avobenzone component in acetonitrile is reduced. Derivatives containing p-chloro substituents are particularly stable to UV light

    Effects of Fe deficiency and Co substitution in polycrystalline and single crystals of Fe3GeTe2

    Get PDF
    Fe3GeTe2 is a two-dimensional van der Waals material with a ferromagnetic ground state and a maximum transition temperature Tc ∼ 225 K. However, when Fe3GeTe2 is synthesized, lower values of Tc are often reported. This is attributed to a deficiency in the Fe at the 2c site in the crystal structure. Here, we investigate the effect of Fe deficiency and the substitution of Co for Fe on the magnetic properties of this system. We have synthesized both polycrystalline material and single crystals by chemical vapor transport and the flux method, with the largest crystals obtained using the flux method. Cobalt substitution at the Fe site is found to significantly reduce the magnetic transition temperature. Crystals of Fe3GeTe2 grown by chemical vapor transport with ∼ 8% excess Fe in the starting materials display an optimum Fe content and magnetic transition temperature

    Insights into the photoprotection mechanism of the UV filter homosalate

    Get PDF
    Homosalate (HMS) is a salicylate molecule that is commonly included within commercial sunscreen formulations to provide protection from the adverse effects of ultraviolet (UV) radiation exposure. In the present work, the mechanisms by which HMS provides UV photoprotection are unravelled, using a multi-pronged approach involving a combination of time-resolved ultrafast laser spectroscopy in the gas-phase and in solution, laser-induced fluorescence, steady-state absorption spectroscopy, and computational methods. The unique combination of these techniques allow us to show that the enol tautomer of HMS undergoes ultrafast excited state intramolecular proton transfer (ESIPT) upon photoexcitation in the UVB (290–320 nm) region; once in the keto tautomer, the excess energy is predominantly dissipated non-radiatively. Sharp transitions are observed in the LIF spectrum at close-to-origin excitation energies, which points towards the potential presence of a second conformer that does not undergo ESIPT. These studies demonstrate that, overall, HMS exhibits mostly favourable photophysical characteristics of a UV filter for inclusion in sunscreen formulations

    Volume 06

    Get PDF
    Introduction from Dean Dr. Charles Ross Caught Between Folklore and the Cold War: The Americanization of Russian Children\u27s Literature by Kristen Gains Graphic Design by Amanda Willis Graphic Design by Holly Backer Prejudices in Swiss German Accents by Monika Gutierrez Photography by Cara O\u27Neal Photography by Sara Nelson Edmund Tyrone\u27s Long Journey through Night by Sasha Silberman Photography by Jessica Beardsley Photography by Jamie Gardner and Edward Peeples The Republican Razor: The Guillotine as a Symbol of Equality by Jamie Clift Graphic Design by Matthew Sakach Genocide: The Lasting Effects of Gender Stratification in Rwanda By Tess Lione and Emily Wilkins Photography by Kelsey Holt and Jessica Page Morocco and the 20 February Movement by Charles Vancampen, Gilbert Hall, Jenny Nehrt, Kasey Dye, Amanda Tharp, Jamie Leeawrik, & Ashley McGee Photography by Emily Poulin Photography by Michael Kropf Improving Performance of Arbitrary Precision Arithmetic Using SIMD Assembly Code Instructions by Nick Pastore Art by Austin Polasky and Morgan Glasco Art by Laura L. Kahler The Effects of the Neutral Response Option on the Extremeness of Participant Responses by Melinda L. Edwards and Brandon C. Smith Graphic Design by Mariah Asbell Graphic Design by Cabell Edmunds College Bullying: An Exploratory Analysis by Amelia D. Perry Photography by Alyssa Hayes Death-Related Crime: Applying Bryant\u27s Conceptual Paradigm of Thanatological Crime to Military Settings by Irina Boothe Graphic Design by Perry Bason Graphic Design by James Earl

    "Give me some space" : exploring youth to parent aggression and violence

    Get PDF
    A small scale qualitative project, undertaken by an interdisciplinary domestic violence research group involving academic researchers and research assistants, with colleagues from Independent Domestic Abuse Services (IDAS), investigated youth aggression and violence against parents. Following the literature review, data was generated through several research conversations with young people (n = 2), through semi-structured interviews with mothers (n = 3) and practitioners (n = 5), and through a practitioner focus group (n = 8). Thematic analysis and triangulation of the data from parents, practitioners and young people, elicited interconnected and complex overarching themes. Young people could be both victim and perpetrator. The witnessing or experiencing of domestic aggression and violence raised the concept of ‘bystander children’. The impact of young people experiencing familial violence was underestimated by parents. For practitioners, the effects of working with domestic violence was shown to be significant - both positively and negatively

    Psychology Meets Biology in COVID-19: What We Know and Why It Matters for Public Health

    Get PDF
    Psychosocial factors are related to immune, viral, and vaccination outcomes. Yet, this knowledge has been poorly represented in public health initiatives during the COVID-19 pandemic. This review provides an overview of biopsychosocial links relevant to COVID-19 outcomes by describing seminal evidence about these associations known prepandemic as well as contemporary research conducted during the pandemic. This focuses on the negative impact of the pandemic on psychosocial health and how this in turn has likely consequences for critically relevant viral and vaccination outcomes. We end by looking forward, highlighting the potential of psychosocial interventions that could be leveraged to support all people in navigating a postpandemic world and how a biopsychosocial approach to health could be incorporated into public health responses to future pandemics
    corecore