Publications by authors named "WEHR R"

Article Synopsis
  • Wetlands produce a lot of methane (a type of gas), but scientists don't fully understand how the tiny organisms in these areas work, which makes it hard to know how much methane will be released as the climate changes.
  • Researchers studied a special wetland in Sweden called Stordalen Mire and discovered that many microbes there can create methane using different sources, like certain chemicals found in the water.
  • This study shows that both methane-producing and methane-using bacteria are important for understanding how gases are emitted from wetlands, especially as permafrost (frozen ground) thaws due to climate change.
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Territorial Differential Meta-Evolution (TDME) is an efficient, versatile, and reliable algorithm for seeking all the global or desirable local optima of a multivariable function. It employs a progressive niching mechanism to optimize even challenging, high-dimensional functions with multiple global optima and misleading local optima. This paper introduces TDME and uses standard and novel benchmark problems to quantify its advantages over HillVallEA, which is the best-performing algorithm on the standard benchmark suite that has been used by all major multimodal optimization competitions since 2013.

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Rationale: The simultaneous analysis of the three stable isotopes of oxygen-triple oxygen isotope analysis-has become an important analytical technique in natural sciences. Determination of the abundance of the rare O isotope in CO gas using magnetic sector isotope ratio mass spectrometry is complicated by the isobaric interference of O by C ( C O O and C O O, both have mass 45 amu). A number of analytical techniques have been used to measure the O/ O ratio of CO gas.

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Combining amphiphilic block copolymers and phospholipids opens new opportunities for the preparation of artificial membranes. The chemical versatility and mechanical robustness of polymers together with the fluidity and biocompatibility of lipids afford hybrid membranes with unique properties that are of great interest in the field of bioengineering. Owing to its straightforwardness, the solvent-assisted method (SA) is particularly attractive for obtaining solid-supported membranes.

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The introduction of chirality into aqueous self-assemblies by employing isotactic block copolymers (BCPs) is an emerging field of interest as it promises special membrane properties of polymersomes not accessible by atactic BCPs. However, isotactic BCPs typically exhibit crystalline behaviour, inducing high membrane stiffness and limiting their applicability in systems involving membrane proteins or sensitive cargo. In this study, an isotactic yet fully amorphous BCP is introduced which overcomes these limitations.

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Melanin and polydopamine are potent biopolymers for the development of biomedical nanosystems. However, applications of melanin or polydopamine-based nanoparticles are limited by drawbacks related to a compromised colloidal stability over long time periods and associated cytotoxicity. To overcome these hurdles, a novel strategy is proposed that mimics the confinement of natural melanin in melanosomes.

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Droughts in a warming climate have become more common and more extreme, making understanding forest responses to water stress increasingly pressing. Analysis of water stress in trees has long focused on water potential in xylem and leaves, which influences stomatal closure and water flow through the soil-plant-atmosphere continuum. At the same time, changes of vegetation water content (VWC) are linked to a range of tree responses, including fluxes of water and carbon, mortality, flammability, and more.

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Here, we introduce an artificial bioluminescent nanocompartment based on the encapsulation of light-producing enzymes, luciferases, inside polymersomes. We exploit nanocompartmentalization to enhance luciferase stability in a cellular environment but also to positively modulate enzyme kinetics to achieve a long-lasting glow type signal. These features pave the way for expanding bioluminescence to nanotechnology-based applications.

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Cells rely upon producing enzymes at precise rates and stoichiometry for maximizing functionalities. The reasons for this optimal control are unknown, primarily because of the interconnectivity of the enzymatic cascade effects within multi-step pathways. Here, an elegant strategy for studying such behavior, by controlling segregation/combination of enzymes/metabolites in synthetic cell-sized compartments, while preserving vital cellular elements is presented.

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Aqueous self-assembly of amphiphilic block copolymers is studied extensively for biomedical applications like drug delivery and nanoreactors. The commonly used hydrophilic block poly(ethylene oxide) (PEO), however, suffers from several drawbacks. As a potent alternative, poly(glycidol) (PG) has gained increasing interest, benefiting from its easy synthesis, high biocompatibility and flexibility as well as enhanced functionality compared to PEO.

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Controllable attachment of proteins to material surfaces is very attractive for many applications including biosensors, bioengineered scaffolds or drug screening. Especially, redox proteins have received considerable attention as a model system not only to understand the mechanism of electron transfer in biological systems, but also the development of novel biosensors. However, current research attempts suffer from denaturation of the protein after its attachment to solid substrates.

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The pharmacokinetics of diclofenac were investigated following single oral doses of 10 mg/kg to chimeric liver humanized and murinized FRG and C57BL/6 mice. In addition, the metabolism and excretion were investigated in chimeric liver humanized and murinized FRG mice. Diclofenac reached maximum blood concentrations of 2.

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The recent development of polymerization-induced self-assembly (PISA) has facilitated the rational synthesis of a range of diblock copolymer worms, which hitherto could only be prepared traditional post-polymerization processing in dilute solution. Herein we explore a new synthetic route to aqueous dispersions of cationic disulfide-functionalized worm gels. This is achieved the PISA synthesis of poly[(glycerol monomethacrylate--glycidyl methacrylate)]--poly(2-hydroxypropyl methacrylate) (P(GMA--GlyMA)-PHPMA) block copolymer worms reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of HPMA.

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The pharmacokinetics and metabolism of lumiracoxib were studied, after administration of single 10mg/kg oral doses to chimeric liver-humanized and murinized FRG mice. In the chimeric humanized mice, lumiracoxib reached peak observed concentrations in the blood of 1.10±0.

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Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R = 0.

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1. The pharmacokinetics and metabolism of lumiracoxib in male C57bl/6J mice were investigated following a single oral dose of 10 mg/kg. 2.

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Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment.

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Q fever is a worldwide zoonotic disease caused by the pathogen Coxiella (C.) burnetii. A wide range of animal species is susceptible to this intracellular bacterium with great importance in ruminants.

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Permafrost contains about 50% of the global soil carbon. It is thought that the thawing of permafrost can lead to a loss of soil carbon in the form of methane and carbon dioxide emissions. The magnitude of the resulting positive climate feedback of such greenhouse gas emissions is still unknown and may to a large extent depend on the poorly understood role of microbial community composition in regulating the metabolic processes that drive such ecosystem-scale greenhouse gas fluxes.

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An intensity-stabilized diode laser absorption spectrometer was developed and used to perform a highly accurate study of the line shape of CO(2) absorption lines, in the spectral region around 5000 cm(-1), belonging to the nu(1) + 2nu(2)(0) + nu(3) combination band, at a temperature of 296.00 K. Standard and complex semiclassical models, including Dicke narrowing and speed-dependent broadening effects, were applied, tested, and compared in the pressure range between 0.

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Fosalvudine tidoxil is a prodrug derived from the nucleoside reverse transcriptase inhibitor 3-deoxy-3-fluorothymidine (FLT; alovudine). FLT effectively inhibits resistant human immunodeficiency virus type 1, but its clinical development was stopped due to bone marrow and liver toxicity. In this study, we examined the long-term in vivo effects of fosalvudine tidoxil on the mitochondrial DNA (mtDNA) contents in rats.

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We report on a new optical implementation of primary gas thermometry based on laser-absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) nu1+2nu2(0)+nu3 transition in CO2 gas at thermodynamic equilibrium. Doppler width measurements as a function of gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of approximately 1.

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An intensity-stabilized laser absorption spectrometer, which incorporates a mirror-extended cavity diode laser, a temperature-stabilized gas cell, and a Michelson interferometer, was developed and applied to a highly accurate investigation of line intensity factors within the nu(1)+2nu(2) (0)+nu(3) combination band of carbon dioxide, around 2 microm wavelength, at a temperature of 296.0 K. This relatively complex apparatus enables one to observe the absorption line shape with high precision and accuracy in such a way that it is possible to retrieve the integrated absorbance with a relative uncertainty better than 0.

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An infrared laser spectrometer based on difference-frequency generation in LiIO(3) is described. The spectrometer has a frequency uncertainty of less than 1 MHz and a signal-to-noise ratio between 3000:1 and 10,000:1. These properties allow the spectrometer to be used for studies of the non-Lorentzian and non-Voigt character of absorption line shapes in atmospheric trace gases.

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