3,303 results match your criteria yields dynamic

Nanobody-Dependent Detection of Microcystis aeruginosa by ELISA and Thermal Lens Spectrometry.

Appl Biochem Biotechnol 2021 Apr 19. Epub 2021 Apr 19.

Laboratory for Environmental and Life Sciences, University of Nova Gorica, Vipavska cesta 13, 5000, Nova Gorica, SI, Slovenia.

Nanobodies against cell surface antigens of toxic cyanobacteria Microcystis aeruginosa were recovered by whole-cell biopanning of a naïve phage display library of nanobodies. Six unique sequences were identified and three sub-cloned and purified as fusion immunoreagents together with either green fluorescent protein or AviTag to be used for diagnostics. The yields of nanobody constructs were in the range of 5-10 mg/l and their specificity and sensitivity was initially evaluated by immunofluorescence and by fluorescent enzyme-linked immunosorbent assay (ELISA) using fluorescent nanobodies. Read More

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Dynamic shrinkage in time-varying parameter stochastic volatility in mean models.

J Appl Econ (Chichester Engl) 2021 Mar 6;36(2):262-270. Epub 2021 Jan 6.

Department of Economics Salzburg Centre of European Union Studies University of Salzburg Mönchsberg 2A Salzburg 5020 Austria.

Successful forecasting models strike a balance between parsimony and flexibility. This is often achieved by employing suitable shrinkage priors that penalize model complexity but also reward model fit. In this article, we modify the stochastic volatility in mean (SVM) model by introducing state-of-the-art shrinkage techniques that allow for time variation in the degree of shrinkage. Read More

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Improving the design of an oxidative stress sensing biosensor in yeast.

FEMS Yeast Res 2021 Apr 17. Epub 2021 Apr 17.

Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 1A1, Canada.

Transcription factor (TF)-based biosensors have proven useful for increasing biomanufacturing yields, large-scale functional screening, and in environmental monitoring. Most yeast TF-based biosensors are built from natural promoters, resulting in large DNA parts retaining considerable homology to the host genome, which can complicate biological engineering efforts. There is a need to explore smaller, synthetic biosensors to expand the options for regulating gene expression in yeast. Read More

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Evaluation of -Diacetates as Alternative Reagents for Enzymatic Regio- and Stereoselective Acylation of Alcohols.

J Org Chem 2021 Apr 16. Epub 2021 Apr 16.

Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland.

diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without / isomerization of the double bond. Read More

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Azo-hydrazone molecular switches: Synthesis and NMR conformational investigation.

Magn Reson Chem 2021 Apr 15. Epub 2021 Apr 15.

Department of Science and Environment, Roskilde University, DK-4000, Roskilde, Denmark.

A series of five intramolecularly hydrogen-bonded arylhydrazone (aryl = phenol, p-nitrophenol, anisole, quinoline) derived molecular switches have been synthesized and characterized by NMR and HRMS techniques. It was found that the compounds exist as different isomers in solution. An investigation of both conformational and/or configurational changes of the azo-hydrazone compounds was carried out by 1D H- and C- spectra, 2D NOESY, COSY, HSQC and HMBC techniques. Read More

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Production of itaconic acid from alkali pretreated lignin by dynamic two stage bioconversion.

Nat Commun 2021 04 15;12(1):2261. Epub 2021 Apr 15.

Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.

Expanding the portfolio of products that can be made from lignin will be critical to enabling a viable bio-based economy. Here, we engineer Pseudomonas putida for high-yield production of the tricarboxylic acid cycle-derived building block chemical, itaconic acid, from model aromatic compounds and aromatics derived from lignin. We develop a nitrogen starvation-detecting biosensor for dynamic two-stage bioproduction in which itaconic acid is produced during a non-growth associated production phase. Read More

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Integrative inference of transcriptional networks in Arabidopsis yields novel ROS signalling regulators.

Nat Plants 2021 Apr 12;7(4):500-513. Epub 2021 Apr 12.

Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.

Gene regulation is a dynamic process in which transcription factors (TFs) play an important role in controlling spatiotemporal gene expression. To enhance our global understanding of regulatory interactions in Arabidopsis thaliana, different regulatory input networks capturing complementary information about DNA motifs, open chromatin, TF-binding and expression-based regulatory interactions were combined using a supervised learning approach, resulting in an integrated gene regulatory network (iGRN) covering 1,491 TFs and 31,393 target genes (1.7 million interactions). Read More

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Fragment-linking peptide design yields a high-affinity ligand for microtubule-based transport.

Cell Chem Biol 2021 Mar 31. Epub 2021 Mar 31.

School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK. Electronic address:

Synthetic peptides are attractive candidates to manipulate protein-protein interactions inside the cell as they mimic natural interactions to compete for binding. However, protein-peptide interactions are often dynamic and weak. A challenge is to design peptides that make improved interactions with the target. Read More

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Characterization and purification of pentameric chimeric protein particles using asymmetric flow field-flow fractionation coupled with multiple detectors.

Anal Bioanal Chem 2021 Apr 10. Epub 2021 Apr 10.

C2P s.r.o. (NEXARS), The Campus Science Park, Palachovo náměstí 726/2, 625 00, Brno, Czech Republic.

Porcine circovirus causes the post-weaning multi-systemic wasting syndrome. Despite the existence of commercial vaccines, the development of more effective and cheaper vaccines is expected. The usage of chimeric antigens allows serological differentiation between naturally infected and vaccinated animals. Read More

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A Ratiometric Fluorescent Biosensor Reveals Dynamic Regulation of Long-Chain Fatty Acyl-CoA Esters Metabolism.

Angew Chem Int Ed Engl 2021 Apr 10. Epub 2021 Apr 10.

Central China Normal University, Chemistry, CHINA.

Despite increasing awareness of the biological impacts of long-chain fatty acyl-CoA esters (LCACoAs), our knowledge about the subcellular distribution and regulatory functions of these acyl-CoA molecules is limited by a lack of methods for detecting LCACoAs in living cells. Here, we report development of a genetically encoded fluorescent sensor that enables ratiometric quantification of LCACoAs in living cells and subcellular compartments. We demonstrate how this FadR-cpYFP fusion "LACSer sensor" undergoes LCACoA-induced conformational changes reflected in easily detectable fluorescence responses, and show proof-of-concept for real-time monitoring of LCACoAs in human cells. Read More

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Ventral Pallidum GABA Neurons Mediate Motivation Underlying Risky Choice.

J Neurosci 2021 Apr 6. Epub 2021 Apr 6.

Department of Neurobiology & Behavior, University of California, Irvine, 1203 McGaugh Hall, Irvine, CA 92697.

Pursuing rewards while avoiding danger is an essential function of any nervous system. Here, we examine a new mechanism helping rats negotiate the balance between risk and reward when making high-stakes decisions. Specifically, we focus on GABA neurons within an emerging mesolimbic circuit nexus-the ventral pallidum (VP). Read More

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β2-adrenoceptor ligand efficacy is tuned by a two-stage interaction with the Gαs C terminus.

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455;

Classical pharmacological models have incorporated an "intrinsic efficacy" parameter to capture system-independent effects of G protein-coupled receptor (GPCR) ligands. However, the nonlinear serial amplification of downstream signaling limits quantitation of ligand intrinsic efficacy. A recent biophysical study has characterized a ligand "molecular efficacy" that quantifies the influence of ligand-dependent receptor conformation on G protein activation. Read More

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Improving the Detection of the Contact Point in Active Sensing Antennae by Processing Combined Static and Dynamic Information.

Sensors (Basel) 2021 Mar 5;21(5). Epub 2021 Mar 5.

Escuela Técnica Superior de Ingeniería Industrial de Ciudad Real, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain.

The design and application of sensing antenna devices that mimic insect antennae or mammal whiskers is an active field of research. However, these devices still require new developments if they are to become efficient and reliable components of robotic systems. We, therefore, develop and build a prototype composed of a flexible beam, two servomotors that drive the beam and a load cell sensor that measures the forces and torques at the base of the flexible beam. Read More

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Multi-Time Resolution Ensemble LSTMs for Enhanced Feature Extraction in High-Rate Time Series.

Sensors (Basel) 2021 Mar 10;21(6). Epub 2021 Mar 10.

Air Force Research Laboratory, Munitions Directorate, Fuzes Branch, Eglin Air Force Base, FL 32542, USA.

Systems experiencing high-rate dynamic events, termed high-rate systems, typically undergo accelerations of amplitudes higher than 100 g-force in less than 10 ms. Examples include adaptive airbag deployment systems, hypersonic vehicles, and active blast mitigation systems. Given their critical functions, accurate and fast modeling tools are necessary for ensuring the target performance. Read More

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Interstrand Cross-Link Formation Involving Reaction of a Mispaired Cytosine Residue with an Abasic Site in Duplex DNA.

Chem Res Toxicol 2021 Apr 30;34(4):1124-1132. Epub 2021 Mar 30.

Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States.

The formation of interstrand cross-links in duplex DNA is important in biology, medicine, and biotechnology. Interstrand cross-links arising from the reaction of the aldehyde residue of an abasic (apurinic or AP) site with the exocyclic amino groups of guanine or adenine residues on the opposing strand of duplex DNA have previously been characterized. The canonical nucleobase cytosine has an exocyclic amino group but its ability to form interstrand cross-links by reaction with an AP site has not been characterized before now. Read More

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Stereoselective directed cationic cascades enabled by molecular anchoring in terpene cyclases.

Angew Chem Int Ed Engl 2021 Mar 26. Epub 2021 Mar 26.

Universitaet Stuttgart, Technische Biochemie, Allmandring 31, 70569, Stuttgart, GERMANY.

CCascade reactions appeared as a cutting-edge strategy [1] to streamline the assembly of complex structural scaffolds from naturally available precursors in an atom-, as well as time, labor- and cost-efficient way [2,3] . We herein report a strategy to control cationic cyclization cascades by exploiting the ability of anchoring dynamic substrates in the active site of terpene cyclases via designed hydrogen bonding. Thereby, it is possible to induce 'directed' cyclizations in contrast to established 'non-stop' cyclizations [4,5] (99:1) and predestinate cascade termination at otherwise catalytically barely accessible intermediates. Read More

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Synthesis of a Novel Flame Retardant Containing Phosphorus, Nitrogen, and Silicon and Its Application in Epoxy Resin.

ACS Omega 2021 Mar 1;6(10):7094-7105. Epub 2021 Mar 1.

Hangzhou Rongfang Pressure Sensitive New Material Co., Ltd, Shanghai 200237, China.

A novel flame retardant (TDA) containing phosphorus, nitrogen, and silicon was synthesized successfully via a controllable ring-opening addition reaction between 1,3,5-triglycidyl isocyanurate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 3-aminopropyltriethoxysilane, and TDA was then blended with diglycidyl ether of bisphenol A to prepare flame-retardant epoxy resins (EPs). The chemical structure and components of TDA were confirmed by Fourier transform infrared (FTIR) spectra, P nuclear magnetic resonance, and X-ray photoelectron spectroscopy. Thermogravimetric analysis results indicated that after the introduction of TDA, cured EP maintained good thermal stability with a minimum initial decomposition temperature of 337. Read More

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Intercluster exchanges leading to hydride-centered bimetallic clusters: a multi-NMR, X-ray crystallographic, and DFT study.

Dalton Trans 2021 Apr 18;50(13):4727-4734. Epub 2021 Mar 18.

Department of Chemistry, National Dong Hwa University, Hualien 974301, Taiwan, Republic of China.

Encouraged by the successful syntheses of alloy nanoclusters (or nanoparticles) via intercluster (or interparticle) reactions, herein we apply this methodology to prepare a series of bimetallic hydride clusters. Mixing of two clusters, [Ag(H){EP(OPr)}] (E = S, 1; Se, 3) and [Cu(H){EP(OPr)}] (E = S, 2; Se, 4), yields two series of hydride-centered bimetallic clusters, [CuAg(H){EP(OPr)}] (x = 0-7; E = S, 5; Se, 6). Their compositions are fully characterized by positive-mode ESI-MS spectrometry, multi-NMR spectroscopy, and the structures of [CuAg(H){SP(OPr)}] (5a) and [CuAg(H){SeP(OPr)}] (6a) by single crystal X-ray diffraction. Read More

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Improving Pesticide Uptake Modeling into Potatoes: Considering Tuber Growth Dynamics.

J Agric Food Chem 2021 Mar 17;69(12):3607-3616. Epub 2021 Mar 17.

Quantitative Sustainability Assessment, Department of Technology, Management and Economics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.

To explore pesticide uptake from soil into a growing potato, a moving-boundary dynamic model is proposed on the basis of the radical diffusion process of a chemical to a sphere. This model, which considers the logistic growth of the potato tuber, describes two hypothetical processes of chemical diffusion within a growing tuber. The model was tested in an illustrative case study for an application of chlorpyrifos. Read More

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Relationship between dynamic BOLD activity and functional network connectivity: Characterization of schizophrenia subgroups.

Brain Connect 2021 Mar 16. Epub 2021 Mar 16.

University of Maryland Baltimore County, 14701, Baltimore, Maryland, United States;

Aim: In this work, we propose a novel use of adaptively constrained independent vector analysis (acIVA) to effectively capture the temporal and spatial properties of dynamic blood-oxygen-level-dependent (BOLD) activity (dBA), and efficiently quantify the spatial property of dBA (sdBA). We also propose to incorporate dBA into the study of brain dynamics to gain insight into activity-connectivity co-evolution patterns.

Introduction: Studies of the dynamics of human brain using functional magnetic resonance imaging (fMRI) has enabled the identification of unique functional network connectivity (FNC) states and provided new insights into mental disorders. Read More

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Surface hydrophobization of pulp fibers in paper sheets via gas phase reactions.

Int J Biol Macromol 2021 Mar 15;180:80-87. Epub 2021 Mar 15.

Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria; CD Laboratory for Fiber Swelling and Paper Performance, Inffeldgasse 23, 8010 Graz, Austria.

Hydrophobization of cellulosic materials and particularly paper products is a commonly used procedure to render papers more resistant to water and moisture. Here, we explore the hydrophobization of unsized paper sheets via the gas phase. We employed three different compounds, namely palmitoyl chloride (PCl), trifluoroacetic anhydride/acetic anhydride (TFAA/AcO)) and hexamethyldisilazane (HMDS) which were vaporized and allowed to react with the paper sheets via the gas phase. Read More

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Mapping arginase expression with F-fluorinated late-generation arginase inhibitors derived from quaternary α-amino acids.

J Nucl Med 2021 Mar 12. Epub 2021 Mar 12.

Groningen University Hospital, Netherlands.

Arginase hydrolyzes ʟ-arginine and influences levels of polyamines and nitric oxide (NO•). Arginase overexpression is associated with inflammations and tumorigenesis. Thus, radiolabeled arginase inhibitors may be suitable positron emission tomography (PET) tracers for staging arginase-related pathophysiologies. Read More

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Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent.

Nat Commun 2021 03 10;12(1):1572. Epub 2021 Mar 10.

Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.

Macrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Read More

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Path probability ratios for Langevin dynamics-Exact and approximate.

J Chem Phys 2021 Mar;154(9):094102

Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Arnimallee 22, D-14195 Berlin, Germany.

Path reweighting is a principally exact method to estimate dynamic properties from biased simulations-provided that the path probability ratio matches the stochastic integrator used in the simulation. Previously reported path probability ratios match the Euler-Maruyama scheme for overdamped Langevin dynamics. Since molecular dynamics simulations use Langevin dynamics rather than overdamped Langevin dynamics, this severely impedes the application of path reweighting methods. Read More

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Triple Clipped Histogram Based Medical Image Enhancement Using Spatial Frequency.

IEEE Trans Nanobioscience 2021 Mar 4;PP. Epub 2021 Mar 4.

In this paper, a novel triple clipped histogram model-based fusion approach has been proposed to improve the basics features, brightness preservation and contrast of the medical images. This incorporates the features of the equalized image and input image together. In the initial step, the low-contrast medical image is equalized using the triple clipped dynamic histogram equalization technique for which the histogram of the input medical image is split into three sections on the basis of standard deviation with almost equal number of pixels. Read More

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Measurement of the Lag Correction Factor in Low-Dose Fluoroscopic Imaging.

IEEE Trans Med Imaging 2021 Mar 2;PP. Epub 2021 Mar 2.

Lag signals occur at images sequentially acquired from a flat-panel (FP) dynamic detector in fluoroscopic imaging due to charge trapping in photodiodes and incomplete readouts. This lag signal produces various lag artifacts and prevents analyzing detector performances because the measured noise power spectrum (NPS) values are reduced. In order to design dynamic detectors, which produce low lag artifacts, accurately evaluating the detector lag through its quantitative measurement is required. Read More

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A Self-Assembled Homochiral Radical Cage with Paramagnetic Behaviors.

Angew Chem Int Ed Engl 2021 Mar 2. Epub 2021 Mar 2.

Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China.

Condensation of an inherently C -symmetric polychlorotriphenylmethyl (PTM) radical trisaldehyde with tris(2-aminoethyl)amine (TREN) yields a [4+4] tetrahedral radical cage as a racemic pair of homochiral enantiomers in 75 % isolated yield. The structure was characterized by X-ray crystallography, confirming the homochirality of each cage framework. The homochirality results from intramolecular [CH⋅⋅⋅π] and hydrogen-bonding interactions within the cage framework. Read More

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Calcium-dependent protein kinase 2 plays a positive role in the salt stress response in potato.

Plant Cell Rep 2021 Mar 2. Epub 2021 Mar 2.

Laboratorio de Transducción de Señales en Plantas, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires (C.A.B.A., Buenos Aires, Argentina.

Key Message: StCDPK2 is an early player in the salt stress response in potato plants; its overexpression promoted ROS scavenging, chlorophyll stability, and the induction of stress-responsive genes conferring tolerance to salinity. The salinity of soils affects plant development and is responsible for great losses in crop yields. Calcium-dependent protein kinases (CDPKs) are sensor-transducers that decode Ca signatures triggered by abiotic stimuli and translate them into physiological responses. Read More

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Recommendations for offline combustion-based nitrogen isotopic analysis of silicate minerals and rocks.

Rapid Commun Mass Spectrom 2021 May;35(10):e9075

Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada.

Rationale: Due to isotope fractionations during partial nitrogen release from minerals and rocks, the complete extraction of nitrogen for analysis is crucial to ensure high-quality nitrogen isotopic data. However, the appropriate nitrogen extraction conditions (e.g. Read More

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Enantioselective Synthesis of α-Aryl-β2-Amino-esters via Cooperative Isothiourea and Brønsted Acid Catalysis.

Angew Chem Int Ed Engl 2021 Mar 1. Epub 2021 Mar 1.

University of St Andrews, Chemistry, UNITED KINGDOM.

The synthesis of α-aryl-β 2 -amino esters through enantioselective aminomethylation of an arylacetic acid ester in high yields and enantioselectivity via cooperative isothiourea and Brønsted acid catalysis is demonstrated. The scope and limitations of this process are explored (25 examples, up to 94% yield and 96:4 er), with applications to the synthesis of ( S )-Venlafaxine·HCl and ( S )-Nakinadine B. Mechanistic studies are consistent with a C(1)-ammonium enolate pathway being followed rather than an alternative dynamic kinetic resolution process. Read More

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