bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptional activation of muscle atrophy promotes cardiac muscle remodeling during mammalian hibernation
Authors: Zhang Yichi , Aguilar Oscar A. , Storey Kenneth B. 
Published: August 2016

Background.Mammalian hibernation in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is characterized by dramatic changes on a physiological and molecular level. During hibernation, mammalian hearts show a propensity to hypertrophy due to the need for increasing contractility to pump colder and more viscous blood. While cardiac hypertrophy is quite often a process characterized by decompensation, the ground squirrel studied is an excellent model of cardiac plasticity and cardioprotection under conditions of hypothermia and ischemia. The forkhead box O (Foxo) family of proteins and myogenin (MyoG) are transcription factors that control protein degradation and muscle atrophy by regulating the expression of the E3 ubiquitin ligases, MAFbx and MuRF1. These ligases are part of the ubiquitin proteasome system by transferring ubiquitin to proteins and targeting these proteins for degradation. Regulation of Foxo1 and 3a occurs through phosphorylation at different residues. The threonine-24 (Thr-24) and serine-319 (Ser-319) residues on Foxo1, and the Thr-32 residue on Foxo3a are phosphorylated by Akt, leading to cytoplasmic localization of Foxo. We propose that the described mechanism contributes to the changes taking place in cardiac muscle throughout hibernation.Methods.Total and phosphorylated protein levels of Foxo1 and Foxo3a, as well as total protein levels of MyoG, MAFbx, and MuRF1, were studied using immunoblotting.Results.Immunoblotting results demonstrated upregulations in Foxo1 and Foxo3a total protein levels (1.3- and 4.5-fold increases relative to euthermic control, for Foxo1 and 3a respectively) during late torpor, and protein levels remained elevated throughout the rest of torpor and at interbout arousal. We also observed decreases in inactive, phosphorylated Foxo1 and 3a proteins during throughout torpor, where levels of p-Foxo1 Ser319and Thr24, as well as p-Foxo3a Thr32decreased by at least 45% throughout torpor. MyoG was upregulated only during late torpor by 2.4-fold. Protein levels of MAFbx and MuRF1 increased in late torpor as well as during early arousal by as much as 2.8-fold, and MAFbx levels remained elevated during interbout arousal, whereas MuRF1 levels returned to control levels.Discussion.The present results indicate that upregulation and activation of Foxo1 and 3a, in addition to the increase in MyoG levels at late torpor, may be upregulating the expression of MAFbx and MuRF1. These findings suggest that there is activation of the ubiquitin proteasome system (UPS) as ground squirrels arouse from torpor. Therefore, the signalling pathway involving MyoG, and the E3 ligases MAFbx and MuRF1, plays a significant role in cardiac muscle remodelling during hibernation. These findings provide insights into the regulation of protein degradation and turnover in the cardiac muscle of a hibernator model.
Delivering a medical school elective with massive open online course (MOOC) technology
Authors: Robinson Robert 
Published: August 2016

Introduction:The educational technology of massive open online courses (MOOCs) has been successfully applied in a wide variety of disciplines and are an intense focus of educational research at this time. Educators are now looking to MOOC technology as a means to improve professional medical education, but very little is known about how medical MOOCs compare with traditional content delivery.Methods:A retrospective analysis of the course evaluations for the Medicine as a Business elective by fourth-year medical students at Southern Illinois University School of Medicine (SIU-SOM) for the 2012–2015 academic years was conducted. This course was delivered by small group flipped classroom discussions for 2012–2014 and delivered via MOOC technology in 2015. Learner ratings were compared between the two course delivery methods using routinely collected course evaluations.Results:Course enrollment has ranged from 6–19 students per year in the 2012–2015 academic years. Student evaluations of the course are favorable in the areas of effective teaching, accurate course objectives, meeting personal learning objectives, recommending the course to other students, and overall when rated on a 5-point Likert scale. The majority of all student ratings (76–95%) of this elective course are for the highest possible choice (Strongly agree or Excellent) for any criteria, regardless if the course was delivered via a traditional or MOOC format. Statistical analysis of these ratings suggests that the Effective Teacher and Overall Evaluations did not statistically differ between the two delivery formats.Discussion:Student ratings of this elective course were highly similar when delivered in a flipped classroom format or by using MOOC technology. The primary advantage of this new course format is flexibility of time and place for learners, allowing them to complete the course objectives when convenient for them. The course evaluations suggest this is a change that is acceptable to the target audience.Conclusions:This study suggests that learner evaluations of a fourth-year medical school elective course do not significantly differ when delivered by flipped classroom group discussions or via MOOC technology in a very small single center observational study. Further investigation is required to determine if this delivery method is an acceptable and effective means of teaching in the medical school environment.
Ion Larmor radius effects near a reconnection X line at the magnetopause: THEMIS observations and simulation comparison
Authors: Phan T. D. , Shay M. A. , Haggerty C. C. , Gosling J. T. , Eastwood J. P. , Fujimoto M. , Malakit K. , Mozer F. S. , Cassak P. A. , Oieroset M. , Angelopoulos V. 
Published: August 2016

AbstractWe report a Time History of Events and Macroscale Interactions during Substorms (THEMIS‐D) spacecraft crossing of a magnetopause reconnection exhaust ~9 ion skin depths (di) downstream of an X line. The crossing was characterized by ion jetting at speeds substantially below the predicted reconnection outflow speed. In the magnetospheric inflow region THEMIS detected (a) penetration of magnetosheath ions and the resulting flows perpendicular to the reconnection plane, (b) ion outflow extending into the magnetosphere, and (c) enhanced electron parallel temperature. Comparison with a simulation suggests that these signatures are associated with the gyration of magnetosheath ions onto magnetospheric field lines due to the shift of the flow stagnation point toward the low‐density magnetosphere. Our observations indicate that these effects, ~2–3 di in width, extend at least 9 di downstream of the X line. The detection of these signatures could indicate large‐scale proximity of the X line but do not imply that the spacecraft was upstream of the electron diffusion region.
Impact of semidiurnal tidal variability during SSWs on the mean state of the ionosphere and thermosphere
Authors: Pedatella N. M. , Richmond A. D. , Maute A. , Liu H.‐L. 
Published: August 2016

AbstractObservations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites reveal a global reduction in the zonal and diurnal mean F region peak electron density (NmF2) during sudden stratosphere warmings (SSWs). The present study investigates the source of the global NmF2 decrease by performing numerical experiments with the National Center for Atmospheric Research (NCAR) thermosphere‐ionosphere‐electrodynamics general circulation model. The simulations reveal that the NmF2 reduction coincides with a depletion of thermospheric [O]/[N2], indicating that the NmF2 depletion is related to changes in thermospheric composition during SSWs. Numerical experiments further illustrate that the short‐term (∼10 day) enhancement of the migrating semidiurnal solar tide (SW2) during SSWs is the source of the variability in thermospheric composition. In particular, the enhancement of the SW2 during SSWs alters the lower thermosphere zonal mean circulation, leading to a reduction in atomic oxygen in the lower thermosphere. The atomic oxygen reduction propagates into the upper thermosphere through molecular diffusion, leading to a decrease in [O]/[N2] throughout the low‐ to middle‐latitude thermosphere. It is anticipated that the effects of the SW2 on the ionosphere and thermosphere investigated herein will be modulated by SSW related enhancements of the migrating semidiurnal lunar tide (M2). The magnitude of the combined impact of the SW2 and M2 on the ionosphere‐thermosphere mean state will depend on the relative phasing of the solar and lunar tides. The results demonstrate that in addition to modulating the low‐latitude electrodynamics, tidal variability during SSWs can significantly impact the mean state of the ionosphere and thermosphere.
Modeling hydrological controls on variations in peat water content, water table depth, and surface energy exchange of a boreal western Canadian fen peatland
Authors: Mezbahuddin M. , Grant R. F. , Flanagan L. B. 
Published: August 2016

AbstractImproved predictive capacity of hydrology and surface energy exchange is critical for conserving boreal peatland carbon sequestration under drier and warmer climates. We represented basic processes for water and O2 transport and their effects on ecosystem water, energy, carbon, and nutrient cycling in a process‐based model ecosys to simulate effects of seasonal and interannual variations in hydrology on peat water content, water table depth (WTD), and surface energy exchange of a Western Canadian fen peatland. Substituting a van Genuchten model (VGM) for a modified Campbell model (MCM) in ecosys enabled a significantly better simulation of peat moisture retention as indicated by higher modeled versus measured R2 and Willmot's index (d) with VGM (R2~0.7, d~0.8) than with MCM (R2~0.25, d~0.35) for daily peat water contents from a wetter year 2004 to a drier year 2009. With the improved peat moisture simulation, ecosys modeled hourly WTD and energy fluxes reasonably well (modeled versus measured R2: WTD ~0.6, net radiation ~0.99, sensible heat >0.8, and latent heat >0.85). Gradually declining ratios of precipitation to evapotranspiration and of lateral recharge to discharge enabled simulation of a gradual drawdown of growing season WTD and a consequent peat drying from 2004 to 2009. When WTD fell below a threshold of ~0.35 m below the hollow surface, intense drying of mosses in ecosys caused a simulated reduction in evapotranspiration and an increase in Bowen ratio during late growing season that were consistent with measurements. Hence, using appropriate water desorption curve coupled with vertical‐lateral hydraulic schemes is vital to accurately simulate peatland hydrology and energy balance.
Some features of scattering problem in a κ‐Deformed minkowski spacetime
Authors: Khodadi M. , Nozari K. 
Published: August 2016

The doubly special relativity (DSR) theories are suggested in order to incorporate an observer‐independent length scale in special theory of relativity. The Magueijo‐Smolin proposal of DSR is realizable through a particular form of the noncommutative (NC) spacetime (known as κ‐Minkowski spacetime) in which the Lorentz symmetry is preserved. In this framework, the NC parameter κ provides the origin of natural cutoff energy scale. Using a nonlinear deformed relativistic dispersion relation along with the Lorentz transformations, we investigate some phenomenological facets of two‐body collision problem (without creation of new particles) in a κ‐Minkowski spacetime. By treating an elastic scattering problem, we study effects of the Planck scale energy cutoff on some relativistic kinematical properties of this scattering problem. The results are challenging in the sense that as soon as one turns on the κ‐spacetime extension, the nature of the two‐body collision alters from elastic to inelastic one. It is shown also that a significant kinematical variable involving in heavy ion collisions, the rapidity, is not essentially an additive quantity under a sequence of the nonlinear representation of the Lorentz transformations.image
Maßgeschneiderte Aufwärtskonvertierungsnanopartikel zur Detektion von Proteinwechselwirkungen in lebenden Zellen
Authors: Drees Christoph , Raj Athira Naduviledathu , Kurre Rainer , Busch Karin B. , Haase Markus , Piehler Jacob 
Published: August 2016

AbstractNanopartikel mit der Fähigkeit zur Aufwärtskonvertierung (“upconversion nanoparticles”, UCNP) wandeln nahinfrarotes in sichtbares Licht bei wesentlich geringeren Anregungsleistungsdichten als in klassischer Zweiphotonenmikroskopie um. In dieser Studie haben wir <50 nm UCNP für die Anwendung als effiziente Lanthanoid‐basierte Donoren für den Resonanzenergietransfer (LRET) in lebenden Zellen entwickelt. Durch die Optimierung der Dotierung und Kern‐Schale‐Struktur für höhere Anregungsdichten konnten wir nicht nur verstärkte UCNP‐Emission, sondern auch massiv erhöhte sensibilisierte Akzeptorfluoreszenz beobachten. Für die Applikation von UCNP in komplexer biologischer Umgebung haben wir eine biokompatible Oberflächenfunktionalisierung mit einem Nanobody, der Grün fluoreszierendes Protein (GFP) erkennt, entwickelt. Hierdurch wurde die schnelle und spezifische Bindung an GFP‐markierte Fusionsproteine in der äußeren Mitochondrienmembran sowie die Detektion von Proteininteraktionen mittels LRET erreicht.
Modifizierung der 5′‐Kappe eukaryotischer mRNA für Klick‐Reaktionen und zur Beeinflussung der Translationseffizienz in lebenden Zellen
Authors: Holstein Josephin M. , Anhäuser Lea , Rentmeister Andrea 
Published: August 2016

AbstractDie 5′‐Kappe ist ein Charakteristikum eukaryotischer mRNAs und nimmt im RNA‐Metabolismus entscheidende Rollen ein, die sich von der Qualitätskontrolle über den Export bis hin zur Translation erstrecken. Die Modifizierung der 5′‐Kappe könnte daher die Modulierung dieser Prozesse und die Erforschung verschiedener biologischer Funktionen ermöglichen. Wir präsentieren einen direkten Ansatz zur Erzeugung einer Auswahl N7‐modifizierter Kappen basierend auf der hoch promiskuitiven Methyltransferase Ecm1. Wir zeigen, dass diese sowie N2‐modifizierte 5′‐Kappen zur Steuerung der Translation entsprechender mRNAs in vitro und in Zellen genutzt werden können. Entsprechende Modifikationen ermöglichen die anschließende Anwendung bioorthogonaler Reaktionen, z. B. die intrazelluläre Markierung einer Ziel‐mRNA in lebenden Zellen. Die effiziente und vielseitige Manipulierung des N7‐Atoms der mRNA‐Kappe ist ein wertvoller Beitrag zum Methodenrepertoire der chemischen Biologie.
Monodisperse Cylindrical Micelles of Controlled Length with a Liquid‐Crystalline Perfluorinated Core by 1D “Self‐Seeding”
Authors: Li Xiaoyu , Jin Bixin , Gao Yang , Hayward Dominic W. , Winnik Mitchell A. , Luo Yunjun , Manners Ian 
Published: August 2016

AbstractPrecise control over the morphology and dimensions of block copolymer (BCP) micelles has attracted interest due to the potential of this approach to generate functional nanostructures. Incorporation of liquid crystalline (LC) block can provide additional ways to vary micellar morphologies, but the formation of uniform micelles with controllable dimensions from LC BCPs has not yet been realized. Herein, we report the preparation of monodisperse cylindrical micelles with a LC poly(2‐(perfluorooctyl)ethyl methacrylate (PFMA) core via a fragmentation‐thermal annealing (F‐TA) process, resembling the “self‐seeding” process of crystalline BCP micelles. The average length of the cylinders increases with annealing temperature, with a narrow length distribution (Lw/Ln<1.1). We also demonstrate the potential application of the cylinders with LC cores as a cargo‐carrier by the successful incorporation of a hydrophobic fluorescent dye tagged with a fluorooctyl group.
Concerted Rattling in CsAg5Te3 Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance
Authors: Lin Hua , Tan Gangjian , Shen Jin‐Ni , Hao Shiqiang , Wu Li‐Ming , Calta Nicholas , Malliakas Christos , Wang Si , Uher Ctirad , Wolverton Christopher , Kanatzidis Mercouri G. 
Published: August 2016

AbstractThermoelectric (TE) materials convert heat energy directly into electricity, and introducing new materials with high conversion efficiency is a great challenge because of the rare combination of interdependent electrical and thermal transport properties required to be present in a single material. The TE efficiency is defined by the figure of merit ZT=(S2σ) T/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the total thermal conductivity, and T is the absolute temperature. A new p‐type thermoelectric material, CsAg5Te3, is presented that exhibits ultralow lattice thermal conductivity (ca. 0.18 Wm−1 K−1) and a high figure of merit of about 1.5 at 727 K. The lattice thermal conductivity is the lowest among state‐of‐the‐art thermoelectrics; it is attributed to a previously unrecognized phonon scattering mechanism that involves the concerted rattling of a group of Ag ions that strongly raises the Grüneisen parameters of the material.
Gold lässt Fibrillen wachsen: der Mechanismus der oberflächenunterstützten Amyloid‐Aggregation
Authors: Gladytz Anika , Abel Bernd , Risselada Herre Jelger 
Published: August 2016

AbstractDie Frage, wie Amyloidfibrillenbildung von Oberflächen beeinflusst wird, ist entscheidend für das Verständnis des Prozesses in vivo. Wir haben eine Kombination von kinetischen Experimenten und Moleküldynamiksimulationen angewendet, um aufzuklären, wie (Modell‐)Oberflächen die Fibrillenbildung der amyloidbildenden Sequenzen des Prionenproteins SUP35 und des Insel‐Amyloid‐Polypeptids beeinflussen. Kinetische Daten legen nahe, dass eine Restrukturierung der initialen Peptidkorona um die kolloidalen Goldnanopartikel der zeitlimitierende Schritt ist. Moleküldynamiksimulationen zeigen, dass partielle Physisorption an der Oberfläche zur Bildung von geordneten Monolagen führt, die die Bildung von parallelen, kritischen Oligomeren stimuliert. Der generelle Mechanismus beinhaltet, dass die zugrundeliegende Peptid‐Peptid‐ und die Peptid‐Oberflächen‐Wechselwirkung in der gleichen Größenordnung liegen müssen, um die Fibrillenbildung zu beschleunigen.
tRNA Shifts the G‐quadruplex–Hairpin Conformational Equilibrium in RNA towards the Hairpin Conformer
Authors: Rode Ambadas B. , Endoh Tamaki , Sugimoto Naoki 
Published: August 2016

AbstractNon‐coding RNAs play important roles in cellular homeostasis and are involved in many human diseases including cancer. Intermolecular RNA–RNA interactions are the basis for the diverse functions of many non‐coding RNAs. Herein, we show how the presence of tRNA influences the equilibrium between hairpin and G‐quadruplex conformations in the 5′ untranslated regions of oncogenes and model sequences. Kinetic and equilibrium analyses of the hairpin to G‐quadruplex conformational transition of purified RNA as well as during co‐transcriptional folding indicate that tRNA significantly shifts the equilibrium toward the hairpin conformer. The enhancement of relative translation efficiency in a reporter gene assay is shown to be due to the tRNA‐mediated shift in hairpin‐G‐quadruplex equilibrium of oncogenic mRNAs. Our findings suggest that tRNA is a possible therapeutic target in diseases in which RNA conformational equilibria is dysregulated.
Lanthanide‐Catalyzed Reversible Alkynyl Exchange by Carbon–Carbon Single‐Bond Cleavage Assisted by a Secondary Amino Group
Authors: Shao Yinlin , Zhang Fangjun , Zhang Jie , Zhou Xigeng 
Published: August 2016

AbstractLanthanide‐catalyzed alkynyl exchange through C−C single‐bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β‐alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo‐ and cross‐dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions.
Mercury Methylation by Cobalt Corrinoids: Relativistic Effects Dictate the Reaction Mechanism
Authors: Demissie Taye B. , Garabato Brady D. , Ruud Kenneth , Kozlowski Pawel M. 
Published: August 2016

AbstractThe methylation of HgII(SCH3)2 by corrinoid‐based methyl donors proceeds in a concerted manner through a single transition state by transfer of a methyl radical, in contrast to previously proposed reaction mechanisms. This reaction mechanism is a consequence of relativistic effects that lower the energies of the mercury 6p1/2 and 6p3/2 orbitals, making them energetically accessible for chemical bonding. In the absence of spin–orbit coupling, the predicted reaction mechanism is qualitatively different. This is the first example of relativity being decisive for the nature of an observed enzymatic reaction mechanism.
Rapid Identification of the Receptor‐Binding Specificity of Influenza A Viruses by Fluorogenic Glycofoldamers
Authors: He Xiao‐Peng , Zeng Ya‐Li , Tang Xin‐Ying , Li Na , Zhou Dong‐Ming , Chen Guo‐Rong , Tian He 
Published: August 2016

AbstractThe re‐emergence of influenza raises a global concern that viral pandemics can unpredictably occur. However, effective approaches that can probe the infection risk of influenza viruses for humans are rare. In this work, we develop a glycofoldamer that can rapidly identify the glycan‐receptor specificity of influenza viruses in a high‐throughput manner. The coupling of glycan receptors that can be recognized by hemagglutinin (a surface protein on the virion capsid of influenza) to a fluorogenic‐dye foldamer produces the glycofoldamers with minimal fluorescence in aqueous solution. After interaction with human‐infecting virus strains for only five minutes, the fluorescence intensity of the glycofoldamer is remarkably enhanced with a blue‐shifted emission peak. The probes have also proven effective for the rapid identification of 1) the human‐ or bird‐infecting properties of influenza viruses in a high‐throughput manner and 2) the receptor‐specificity switch of a virus strain by mutations.
Engineered Upconversion Nanoparticles for Resolving Protein Interactions inside Living Cells
Authors: Drees Christoph , Raj Athira Naduviledathu , Kurre Rainer , Busch Karin B. , Haase Markus , Piehler Jacob 
Published: August 2016

AbstractUpconversion nanoparticles (UCNPs) convert near‐infrared into visible light at much lower excitation densities than those used in classic two‐photon absorption microscopy. Here, we engineered <50 nm UCNPs for application as efficient lanthanide resonance energy transfer (LRET) donors inside living cells. By optimizing the dopant concentrations and the core–shell structure for higher excitation densities, we observed enhanced UCNP emission as well as strongly increased sensitized acceptor fluorescence. For the application of these UCNPs in complex biological environments, we developed a biocompatible surface coating functionalized with a nanobody recognizing green fluorescent protein (GFP). Thus, rapid and specific targeting to GFP‐tagged fusion proteins in the mitochondrial outer membrane and detection of protein interactions by LRET in living cells was achieved.