81 research outputs found

    Modulating Photochemical Properties to Enhance the Stability of Electronically Dimmable Eye Protection Devices

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    The study evaluates compatibility of stabilizers with dye doped liquid crystal (LC) scaffolds that are used in electronically dimmable materials. The photodegradation of the materials was investigated and suitable stabilizers were evaluated to slow the degradation process. Various types of benzotriazole-based stabilizers were evaluated for stabilizing the liquid crystals. Based on spin trapping experiments, radicals generated upon UV exposure is likely responsible for the degradation of the system. The radical generation is competitively inhibited by the addition of stabilizers. Abbreviations: LC, liquid crystal; STB, stabilizers

    Radical Reactions with Double Memory of Chirality ( 2 MOC) for the Enantiospecific Synthesis of Adjacent Stereogenic Quaternary Centers in Solution: Cleavage and Bonding Faster than Radical Rotation

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    The solution photochemistry of bis(phenylpyrrolidinonyl)ketones (R,R)-1b and (S,S)-1b exhibited a remarkably high memory of chirality. Stereospecific decarbonylation to products (R,R)-3b and (S,S)-3b, respectively, occurred with an ee of ca. 80%. The reaction is thought to occur along the single state manifold by sequential Norrish type-I α-cleavage decarbonylation, and radical–radical combination in a time scale that is comparable to that required for the radical intermediate to expose its other enantiotopic face by rotation about an axis perpendicular to that of the p orbital (ca. 3–7 ps). The absolute configuration of a key intermediate and that of ketone (R,R)-1b were determined by single-crystal X-ray diffraction and the ee values of the photochemical products with the help of chiral shift reagent (+)-Eu(tfc)3 and chiral LC-MS/ MS. On the basis of the ee and de values at 25 °C, it could be determined that ca. 70% of the bond forming events occur with double memory of chirality, ca. 21% occur after rotation of one radical to form the meso product (R,S)-3b, and only 9% occur after double rotation to form the opposite enantiomer. This report represents the first example of a doubly enantiospecific Norrish type-I and decarbonylation reaction in solution and illustrates potentially efficient ways to obtain compounds with adjacent stereogenic quaternary centers

    B 12 -Mediated, Long Wavelength Photopolymerization of Hydrogels

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    Medical hydrogel applications have expanded rapidly over the past decade. Implantation in patients by non-invasive injection is preferred, but this requires hydrogel solidification from a low viscosity solution to occur in vivo via an applied stimuli. Transdermal photo-crosslinking of acrylated biopolymers with photoinitiators and lights offers a mild, spatiotemporally controlled solidification trigger. However, the current short wavelength initiators limit curing depth and efficacy because they do not absorb within the optical window of tissue (600 - 900 nm). As a solution to the current wavelength limitations, we report the development of a red light responsive initiator capable of polymerizing a range of acrylated monomers. Photo-activation occurs within a range of skin type models containing high biochromophore concentrations

    Common variation near CDKN1A, POLD3 and SHROOM2 influences colorectal cancer risk

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    We performed a meta-analysis of five genome-wide association studies to identify common variants influencing colorectal cancer (CRC) risk comprising 8,682 cases and 9,649 controls. Replication analysis was performed in case-control sets totaling 21,096 cases and 19,555 controls. We identified three new CRC risk loci at 6p21 (rs1321311, near CDKN1A; P = 1.14 × 10(-10)), 11q13.4 (rs3824999, intronic to POLD3; P = 3.65 × 10(-10)) and Xp22.2 (rs5934683, near SHROOM2; P = 7.30 × 10(-10)) This brings the number of independent loci associated with CRC risk to 20 and provides further insight into the genetic architecture of inherited susceptibility to CRC.Swedish Research Council et al.Manuscrip

    Man and the Last Great Wilderness: Human Impact on the Deep Sea

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    The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life – SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO2 and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

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    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    What We Talk About When We Talk About Light

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    [Image: see text] UNESCO (the United Nations Educational, Scientific, and Cultural Organization) has declared 2015 the “International Year of Light and Light-Based Technologies”. In celebration of this proclamation, this Outlook provides a general history of light and its applications, from the earliest moments of the Big Bang through its present impact on all forms of life on the planet. Special emphasis is placed on fundamental advances in the generation and use of artificial light, as well as the harvesting and use of light from the Sun and other natural sources. During the past century, the role of light in the fields of physics, chemistry, and biology has expanded to include emerging fields such as environmental engineering, agriculture, materials science, and biomedicine. In this regard, future research challenges and new potential applications in these areas, in the context of “the central science”, are presented and discussed

    Dynamics of Spin-Correlated Radical Pairs in Non-Ionic Surfactant Solutions

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