Glass polymorphism in Glycerol–water mixtures: II. Experimental studies

We report a detailed experimental study of (i) pressure-induced transformations in glycerol–water mixtures at T = 77 K and P = 0–1.8 GPa, and (ii) heating-induced transformations of glycerol–water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s1–10 K h1) and for the whole range of glycerol mole fractions, wg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (wg Z 0.20), ice (wg r 0.32), and/or ‘‘distorted ice’’ (0 o wg r 0.38). Upon compression, we find that (a) fully vitrified samples at wg Z 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol–water mixtures is shown to be possible only up to wg E 0.32 (T = 77 K). This is rather surprising since it has been known that at wg o 0.38, cooling leads to phase-separated samples with ice and maximally freezeconcentrated solution of wg E 0.38. Accordingly, in the range 0.32 o wg o 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at wg r 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 o wg r 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (wg r 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol–water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex ‘‘phase’’ behavior of glassy binary mixtures due to phase-separation (ice formation) and polyamorphism, and the relevance of sample preparation, concentration as well as cooling rates. The presence of the distorted ice (called ‘‘interphase’’ by us) also explains the debated ‘‘drift anomaly’’ upon melting. These results are compatible with the high-pressure study by Suzuki and Mishima indicating disappearance of polyamorphism at P E 0.03–0.05 GPa at wg E 0.12–0.15 [J. Chem. Phys., 2014, 141, 094505]

Investigating the Direct Meltwater Effect in Terrestrial Oxygenâ Isotope Paleoclimate Records Using an Isotopeâ Enabled Earth System Model

Variations in terrestrial oxygenâ isotope reconstructions from ice cores and speleothems have been primarily attributed to climatic changes of surface air temperature, precipitation amount, or atmospheric circulation. Here we demonstrate with the fully coupled isotopeâ enabled Community Earth System Model an additional process contributing to the oxygenâ isotope variations during glacial meltwater events. This process, termed â the direct meltwater effect,â involves propagating large amounts of isotopically depleted meltwater throughout the hydrological cycle and is independent of climatic changes. We find that the direct meltwater effect can make up 15â 35% of the δ18O signals in precipitation over Greenland and eastern Brazil for large freshwater forcings (0.25â 0.50 sverdrup (106 m3/s)). Model simulations further demonstrate that the direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to both the location and shape of the meltwater. These new modeling results have important implications for past climate interpretations of δ18O.Key PointsA portion of the δ18O signal in landâ based paleoclimate proxies can be attributed to the direct meltwater effect instead of climatic changesThe direct meltwater effect can make up 15â 35% of the δ18O signals in precipitation in Greenland and eastern Brazil for large meltwater eventsThe direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to location and shape dependentPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/1/grl56782_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/2/grl56782-sup-0001-Supporting_Information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/3/grl56782.pd

Fluctuation spectrum of fluid membranes coupled to an elastic meshwork: jump of the effective surface tension at the mesh size

We identify a class of composite membranes: fluid bilayers coupled to an elastic meshwork, that are such that the meshwork's energy is a function $F_\mathrm{el}[A_\xi]$ \textit{not} of the real microscopic membrane area $A$, but of a \textit{smoothed} membrane's area $A_\xi$, which corresponds to the area of the membrane coarse-grained at the mesh size $\xi$. We show that the meshwork modifies the membrane tension $\sigma$ both below and above the scale $\xi$, inducing a tension-jump $\Delta\sigma=dF_\mathrm{el}/dA_\xi$. The predictions of our model account for the fluctuation spectrum of red blood cells membranes coupled to their cytoskeleton. Our results indicate that the cytoskeleton might be under extensional stress, which would provide a means to regulate available membrane area. We also predict an observable tension jump for membranes decorated with polymer "brushes"

Incorporating metapopulation Dynamics to Inform Invasive Species Management: Evaluating Bighead and Silver Carp Control Strategies in the Illinois River

1. Invasive species management can benefit from predictive models that incorporate spatially explicit demographics and dispersal to guide resource allocation decisions. 2. We used invasive bigheaded carps (Hypophthalmichthys spp.) in the Illinois River, USA as a case study to create a spatially explicit model to evaluate the allocation of future management efforts. Specifically, we compared additional harvest (e.g. near the invasion front vs. source populations) and enhanced movement deterrents to meet the management goal of reducing abundance at the invasion front. 3. We found additional harvest in lower river pools (i.e. targeting source populations) more effectively limited population sizes upriver at the invasion front compared to allocating the same harvest levels near the invasion front. Likewise, decreasing passage (i.e. lock and dam structures) at the farthest, feasible downriver location limited invasion front population size more than placing movement deterrents farther upriver. 4. Synthesis and applications. Our work highlights the benefits of adopting a multipronged approach for invasive species management, combining suppression of source populations with disrupting movement between source and sink populations thereby producing compounding benefits for control. Our results also demonstrate the importance of considering metapopulation dynamics for invasive species control programs when achieving long-term management goals

Defining Criteria for Guiding Cancer Patients to Find a Reputable Complementary Medicine Provider: Results of a Literature Review and a Consensus Procedure

Purpose: Even in cases of positive evidence for complementary medicine (CM) therapies, it is still difficult for cancer patients to identify reputable providers. The aim of this study was to develop and evaluate a criteria list to provide guidance to cancer patients seeking a reputable CM provider. Methods: The design combined a literature review, an expert consensus procedure (n=15) and an assessment from three stakeholder perspectives (patients (n=18), CM providers (n=26) and oncology physicians (n=20)). Results: A total of 30 existing CM criteria were extracted from the literature, and 12 more were added by the experts. The main challenge was to define criteria that could easily be applied by the patients. A final comprehensive list of 8 criteria guiding cancer patients to find a reputable CM provider was developed. Conclusion: Health professionals and cancer information services might find the criteria list helpful when aiming to strengthen patients' awareness of quality-related factors associated with CM providers. The criteria developed might be helpful when standards are established for quality assurance in CM in oncology

Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis

Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis