cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Direct Imaging Explorations for Companions around Mid-Late M Stars from the Subaru/IRD Strategic Program
Creators: name: Uyama, Taichi
name: Beichman, Charles
name: Kuzuhara, Masayuki
name: Janson, Markus
name: Kotani, Takayuki
name: Mawet, Dimitri
name: Sato, Bun'ei
name: Tamura, Motohide
name: Ishikawa, Hiroyuki Tako
name: Cale, Bryson
name: Currie, Thayne
name: Harakawa, Hiroki
name: Henning, Thomas
name: Hirano, Teruyuki
name: Hodapp, Klaus
name: Hori, Yasunori
name: Ishizuka, Masato
name: Jacobson, Shane
name: Kasagi, Yui
name: Kokubo, Eiichiro
name: Konishi, Mihoko
name: Kudo, Tomoyuki
name: Kurokawa, Takashi
name: Kusakabe, Nobuhiko
name: Kwon, Jungmi
name: Machida, Masahiro
name: Nakagawa, Takao
name: Narita, Norio
name: Nishikawa, Jun
name: Ogihara, Masahiro
name: Omiya, Masashi
name: Serizawa, Takuma
name: Ueda, Akitoshi
name: Vievard, Sebastien
name: Wang, Ji
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The Subaru telescope is currently performing a strategic program (SSP) using the high-precision near-infrared (NIR) spectrometer IRD to search for exoplanets around nearby mid/late-M~dwarfs via radial velocity (RV) monitoring. As part of the observing strategy for the exoplanet survey, signatures of massive companions such as RV trends are used to reduce the priority of those stars. However, this RV information remains useful for studying the stellar multiplicity of nearby M~dwarfs. To search for companions around such ``deprioritized" M~dwarfs, we observed 14 IRD-SSP targets using Keck/NIRC2 observations with pyramid wavefront sensing at NIR wavelengths, leading to high sensitivity to substellar-mass companions within a few arcseconds. We detected two new companions (LSPM~J1002+1459~B and LSPM~J2204+1505~B) and two new candidates that are likely companions (LSPM~J0825+6902~B and LSPM~J1645+0444~B) as well as one known companion. Including two known companions resolved by the IRD fiber injection module camera, we detected seven (four new) companions at projected separations between $\sim2-20$~au in total. A comparison of the colors with the spectral library suggests that LSPM~J2204+1505~B and LSPM~J0825+6902~B are located at the boundary between late-M and early-L spectral types. Our deep high-contrast imaging for targets where no bright companions were resolved did not reveal any additional companion candidates. The NIRC2 detection limits could constrain potential substellar-mass companions ($\sim10-75\ M_{\rm Jup}$) at 10~au or further. The failure with Keck/NIRC2 around the IRD-SSP stars having significant RV trends makes these objects promising targets for further RV monitoring or deeper imaging with JWST to search for smaller-mass companions below the NIRC2 detection limits.
description: 16 pages, 8 figures, accepted for publication in AJ
Interactions between national and local strategies for the management of aquatic weeds
Creators: name: Mitchell, D. S
Publisher: name: La Trobe
Year: 2023

description: Murray-Darling Freshwater Research Centre

MDFRC item.

Management of aquatic weeds is often handled primarily at the local level. However, both water and water weeds do not recognise political boundaries even when these coincide with rivers or catchment areas. Thus potentially effective management of a weed in one area may be undermined by absence of a complementary program of management in an adjacent area. Authorities in each of the eight States or Territories that make up Australia are separately responsible for managing water weeds in their own State or Territory. Originally there was little coordination of these programs, but during the 1980s a national strategy for control of Australian water weeds has been progressively devised and put into practice. This stresses prevention and includes policies on plant importation, nomination of noxious weeds, development of a research strategy, a public awareness campaign, guidelines on the use of herbicides in or near water, and a field guide. This strategy is currently being incorporated into a National Weeds Strategy.
Treatment of Experimental Autoimmune Encephalomyelitis by Codelivery of Disease Associated Peptide and Dexamethasone in Acetalated Dextran Microparticles
Creators: name: Yang, Yuhong
name: Bachelder, Eric M.
name: Peng, Haiyan
name: Papenfuss, Tracey L.
name: Lee, Priscilla
name: Severin, Mary
name: Vangundy, Zachary
name: Ainslie, Kristy M.
name: Kanthamneni, Naveen
name: Lovett-Racke, Amy E.
name: Probst, G. Duane
name: Guerau-de-Arellano, Mireia
name: Peine, Kevin J.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system that can cause loss of motor function and is thought to result, in part, from chronic inflammation due to an antigen-specific T cell immune response. Current treatments suppress the immune system without antigen specificity, increasing the risks of cancer, chronic infection, and other long-term side effects. In this study, we show treatment of experimental autoimmune encephalomyelitis (EAE), a model of MS, by coencapsulating the immunodominant peptide of myelin oligodendrocyte glycoprotein (MOG) with dexamethasone (DXM) into acetalated dextran (Ac-DEX) microparticles (DXM/MOG/MPs) and administering the microparticles subcutaneously. The clinical score of the mice was reduced from 3.4 to 1.6 after 3 injections 3 days apart with the coencapsulated microparticulate formulation (MOG 17.6 μg and DXM 8 μg). This change in clinical score was significantly greater than observed with phosphate-buffered saline (PBS), empty MPs, free DXM and MOG, DXM/MPs, and MOG/MPs. Additionally, treatment with DXM/MOG/MPs significantly inhibited disease-associated cytokine (e.g., IL-17, GM-CSF) expression in splenocytes isolated in treated mice. Here we show a promising approach for the therapeutic treatment of MS using a polymer-based microparticle delivery platform.
Formation of very low energy states crossing the ionization threshold of argon atoms in strong mid-infrared fields
Creators: name: Wolter, Benjamin
name: Lemell, Christoph
name: Baudisch, Matthias
name: Pullen, Michael G.
name: Tong, Xiao-Min
name: Hemmer, Michaël
name: Senftleben, Arne
name: Schröter, Claus Dieter
name: Ullrich, Joachim
name: Moshammer, Robert
name: Biegert, Jens
name: Burgdörfer, Joachim
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Atomic ionization by intense mid-infrared (mid-IR) pulses produces low electron energy features that the strong-field approximation, which is expected to be valid in the tunneling ionization regime characterized by small Keldysh parameters ($γ\ll 1$), cannot describe. These features include the low-energy structure (LES), the very-low-energy structure (VLES), and the more recently found zero-energy structure (ZES). They result from the interplay between the laser electric field and the atomic Coulomb field which controls the low-energy spectrum also for small $γ$. In the present joint experimental and theoretical study we investigate the vectorial momentum spectrum at very low energies. Using a reaction microscope optimized for the detection of very low energy electrons, we have performed a thorough study of the three-dimensional momentum spectrum well below 1 eV. Our measurements are complemented by quantum and classical simulations, which allow for an interpretation of the LES, VLES and of the newly identified ZES in terms of two-dimensional Coulomb focusing and recapture into Rydberg states, respectively.
description: 18 pages, 7 figures
Enhancement of quantum heat engine by encircling a Liouvillian exceptional point
Creators: name: Bu, J. -T.
name: Zhang, J. -Q.
name: Ding, G. -Y.
name: Li, J. -C.
name: Zhang, J. -W.
name: Wang, B.
name: Ding, W. -Q.
name: Yuan, W. -F.
name: Chen, L.
name: Özdemir, Ş. K.
name: Zhou, F.
name: Jing, H.
name: Feng, M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Quantum heat engines are expected to outperform the classical counterparts due to quantum coherences involved. Here we experimentally execute a single-ion quantum heat engine and demonstrate, for the first time, the dynamics and the enhanced performance of the heat engine originating from the Liouvillian exceptional points (LEPs). In addition to the topological effects related to LEPs, we focus on thermodynamic effects, which can be understood by the Landau-Zener-Stuckelberg process under decoherence. We witness a positive net work from the quantum heat engine if the heat engine cycle dynamically encircles an LEP. Further investigation reveals that, a larger net work is done when the system is operated closer to the LEP. We attribute the enhanced performance of the quantum heat engine to the LZS process, enabled by the eigenenergy landscape in the vicinity of the LEP, and the EP-induced topological transition. Therefore, our results open new possibilities to towards LEP-enabled control of quantum heat engines and of thermodynamic processes in open quantum systems.
description: 7 pages, 3 figures, Supplementary materials can be found in the Download source
BridgeDb and Wikidata: a powerful combination generating interoperable open research
Creators: name: Willighagen, Egon
name: BridgeDb Project
Publisher: name: Zenodo
Year: 2022
Subjects: open science
bridgedb
identifier
interoperability
FAIR

description: Presentation about the NWO Open Science 2021 grant (203.001.121) for BridgeDb. Abstract for the talk: "Like humans have a unique social security number and different phone numbers from various providers, so do proteins and metabolites have a unique structure but different identifiers from various databases. BridgeDb is an interoperability platform that allows combining these databases, by matching database-specific identifiers. These matches are called identifier mappings, and they are indispensable when combining experimental (omics) data with knowledge in reference databases. BridgeDb takes care of this interoperability between gene, protein, metabolite, and other databases, thus enabling seamless integration of many knowledge bases and wet-lab results. Since databases get updated continuously, so should the Open Science BridgeDb project."
A uvbyCaHbeta Analysis of the Old Open Cluster, NGC 6819
Creators: name: Anthony-Twarog, B. J.
name: Deliyannis, C. P.
name: Twarog, B. A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: NGC 6819 is a richly populated, older open cluster situated within the Kepler field. A CCD survey of the cluster on the uvbyCaHbeta system, coupled with proper-motion membership, has been used to isolate 382 highly probable, single-star unevolved main-sequence members over a 20-arcminute field centered on the cluster. From 278 F dwarfs with high precision photometry in all indices, a mean reddening of E(b-y) = 0.117 +/- 0.005 or E(B-V) = 0.160 +/- 0.007 is derived, where the standard errors of the mean include both internal errors and the photometric zero-point uncertainty. With the reddening fixed, the metallicity derived from the same 278 stars is [Fe/H] = -0.116 +/- 0.101 from m_1 and -0.055 +/- 0.033 from hk, for a weighted average of [Fe/H] = -0.06 +/- 0.04, where the quoted standard errors of the mean values include the internal errors from the photometric scatter plus the uncertainty in the photometric zero points. If metallicity is derived using individual reddening values for each star to account for potential reddening variation across the face of the cluster, the analogous result is unchanged. The cluster members at the turnoff of the color-magnitude diagram are used to test and confirm the recently discovered variation in reddening across the face of the cluster, with a probable range in the variation of Delta[E(B-V)] = 0.045 +/-0.015. With the slightly higher reddening and lower [Fe/H] compared to commonly adopted values, isochrone fitting leads to an age of 2.3 +/- 0.2 Gyr for an apparent modulus of (m-M) = 12.40 +/-0.12.
description: WIYN Open Cluster Study LXI; accepted to Astronomical Journal. 11 figures, 2 tables
Center to limb observations and modeling of the Ca I 4227 A line
Creators: name: Supriya, H. D.
name: Smitha, H. N.
name: Nagendra, K. N.
name: Stenflo, J. O.
name: Bianda, M.
name: Ramelli, R.
name: Ravindra, B.
name: Anusha, L. S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The observed center-to-limb variation (CLV) of the scattering polarization in different lines of the Second Solar Spectrum can be used to constrain the height variation of various atmospheric parameters, in particular the magnetic fields via the Hanle effect. Here we attempt to model non-magnetic CLV observations of the $Q/I$ profiles of the Ca I 4227 A line recorded with the ZIMPOL-3 at IRSOL. For modeling, we use the polarized radiative transfer with partial frequency redistribution with a number of realistic 1-D model atmospheres. We find that all the standard FAL model atmospheres, used by us, fail to simultaneously fit the observed ($I$, $Q/I$) at all the limb distances ($μ$). However, an attempt is made to find a single model which can provide a fit at least to the CLV of the observed $Q/I$ instead of a simultaneous fit to the ($I$, $Q/I$) at all $μ$. To this end we construct a new 1-D model by combining two of the standard models after modifying their temperature structures in the appropriate height ranges. This new combined model closely reproduces the observed $Q/I$ at all the $μ$, but fails to reproduce the observed rest intensity at different $μ$. Hence we find that no single 1-D model atmosphere succeeds in providing a good representation of the real Sun. This failure of 1-D models does not however cause an impediment to the magnetic field diagnostic potential of the Ca I 4227 A line. To demonstrate this we deduce the field strength at various $μ$ positions without invoking the use of radiative transfer.
description: 20 pages, 10 figures, Accepted for publication in ApJ
Angular dependence of spin-orbit spin transfer torques
Creators: name: Lee, Ki-Seung
name: Go, Dongwook
name: Manchon, Aurelien
name: Haney, Paul M.
name: Stiles, M. D.
name: Lee, Hyun-Woo
name: Lee, Kyung-Jin
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In ferromagnet/heavy metal bilayers, an in-plane current gives rise to spin-orbit spin transfer torque which is usually decomposed into field-like and damping-like torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the field-like torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the field-like torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the damping-like torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin transfer torques
description: 9 pages, 3 figures
Simulation of a Hard-Spherocylinder Liquid Crystal with the pe
Creators: name: Fischermeier, Ellen
name: Bartuschat, Dominik
name: Preclik, Tobias
name: Marechal, Matthieu
name: Mecke, Klaus
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The pe physics engine is validated through the simulation of a liquid crystal model system consisting of hard spherocylinders. For this purpose we evaluate several characteristic parameters of this system, namely the nematic order parameter, the pressure, and the Frank elastic constants. We compare these to the values reported in literature and find a very good agreement, which demonstrates that the pe physics engine can accurately treat such densely packed particle systems. Simultaneously we are able to examine the influence of finite size effects, especially on the evaluation of the Frank elastic constants, as we are far less restricted in system size than earlier simulations.
Solar Energetic Particle Events with Short and Long Onset Times
Creators: name: Kihara, Kosuke
name: Asai, Ayumi
name: Yashiro, Seiji
name: Nitta, Nariaki V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Gradual solar energetic particle (SEP) events, usually attributed to shock waves driven by coronal mass ejections (CMEs), show a wide variety of temporal behaviors. For example, TO, the >10 MeV proton onset time with respect to the launch of the CME, has a distribution of at least an order of magnitude, even when the source region is not far from the so-called well-connected longitudes. It is important to understand what controls TO, especially in the context of space weather prediction. Here we study two SEP events from the western hemisphere that are different in TO on the basis of >10 MeV proton data from the Geostationary Operations Environmental Satellite, despite similar in the CME speed and longitude of the source regions. We try to find the reasons for different TO, or proton release times, in how the CME-driven shock develops and the Alfvén Mach number of the shock wave reaches some threshold, by combining the CME height-time profiles with radio dynamic spectra. We also discuss how CME-CME interactions and active region properties may affect proton release times.
description: 14 pages, 8 figures, accepted for publication in ApJ
Rapid and Persistent Delivery of Antigen by Lymph Node Targeting PRINT Nanoparticle Vaccine Carrier To Promote Humoral Immunity
Creators: name: Mueller, Sarah N.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2015

description: Nanoparticle delivery of subunit vaccines may increase vaccine efficacy, leading to a wide variety of safe and effective vaccines beyond those available through dosing inactivated or live, attenuated whole pathogens. Here we present a versatile vaccine delivery platform based on PRINT hydrogels made of biocompatible hydroxy-poly(ethylene glycol) (PEG) that is able to activate the complement system by the alternative pathway. These lymph node targeting nanoparticles (NPs) promote the immunogenicity of a model antigen, ovalbumin, showing comparable adjuvant effect to alum. We demonstrate that an antigen-specific humoral response is correlated with antigen delivery to the draining lymph nodes, in particular, B cell rich regions of the lymph nodes. 80 × 180 nm cylindrical NPs were able to sustain prolonged antigen presentation to antigen presenting cells (APCs) and elicit a stronger immune response than nondraining 1 × 1 μm NPs or rapidly clearing soluble antigen. The 80 × 180 nm NPs also show high levels of uptake by key APCs and efficiently stimulate CD4(+) helper T cell proliferation in vivo, further promoting antibody production. These features together produce a significant humoral immune response, superior to that produced by free antigen alone. The simplicity of the chemistries used in antigen conjugation to PRINT NPs confers versatility to this antigen delivery platform, allowing for potential application to many infectious diseases.
Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery in Vivo
Creators: name: Ma, Da
name: Luft, J. Christopher
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2015

description: To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery in vivo is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery in vivo. "Blank" hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to "blank" nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency in vitro. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for in vivo siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels.
Efficient all-optical production of large $^6$Li quantum gases using D$_1$ gray-molasses cooling
Creators: name: Burchianti, A.
name: Valtolina, G.
name: Seman, J. A.
name: Pace, E.
name: De Pas, M.
name: Inguscio, M.
name: Zaccanti, M.
name: Roati, G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We use a gray molasses operating on the D$_1$ atomic transition to produce degenerate quantum gases of $^{6}$Li with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 10$^9$ atoms from 500 to 40 $μ$K in 2 ms. We observe that D$_1$ cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5$\times$10$^{5}$ molecules and weakly-interacting degenerate Fermi gases of $7\times$10$^{5}$ atoms at $T/T_{F}<0.1$ with a typical experimental duty cycle of 11 seconds.
description: 5 pages, 3 figures
The homotopy fixed point set of Lie group actions on elliptic spaces
Creators: name: Buijs, Urtzi
name: Félix, Yves
name: Huerta, Sergio
name: Murillo, Aniceto
Publisher: name: arXiv
Year: 2014
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics

description: Let $G$ be a compact connected Lie group, or more generally a path connected topological group of the homotopy type of a finite CW-complex, and let $X$ be a rational nilpotent $G$-space. In this paper we analyze the homotopy type of the homotopy fixed point set $X^{hG}$, and the natural injection $k\colon X^G\hookrightarrow X^{hG}$. We show that if $X$ is elliptic, that is, it has finite dimensional rational homotopy and cohomology, then each path component of $X^{hG}$ is also elliptic. We also give an explicit algebraic model of the inclusion $k$ based on which we can prove, for instance, that for $G$ a torus, $π_*(k)$ is injective in rational homotopy but, often, far from being a rational homotopy equivalence.
description: 32 pages
Nonreciprocal slow or fast light in anti-$\mathcal{PT}$-symmetric optomechanics
Creators: name: Peng, Meiyu
name: Zhang, Huilai
name: Zhang, Qian
name: Lu, Tian-Xiang
name: Mirza, Imran M.
name: Jing, Hui
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Non-Hermitian systems with anti-parity-time ($\mathcal{APT}$) symmetry have revealed rich physics beyond conventional systems. Here, we study optomechanics in an $\mathcal{APT}$-symmetric spinning resonator and show that, by tuning the rotating speed to approach the exceptional point (EP) or the non-Hermitian spectral degeneracy, nonreciprocal light transmission with a high isolation ratio can be realized. Accompanying this process, nonreciprocal group delay or advance is also identified in the vicinity of EP. Our work sheds new light on manipulating laser propagation with optomechanical EP devices and, in a broader view, can be extended to explore a wide range of $\mathcal{APT}$-symmetric effects, such as $\mathcal{APT}$-symmetric phonon lasers, $\mathcal{APT}$-symmetric topological effects, and $\mathcal{APT}$-symmetric force sensing or accelerator.
description: 9 pages, 4 figures. It has been accepted for publication as a Regular Article in Physical Review A
A Mutational Analysis of Residues Essential for Ligand Recognition at the Human P2Y 1 Receptor
Creators: name: Jiang, Qiaoling
name: Van Rhee, A. Michiel
name: Lee, Brian X.
name: Jacobson, Kenneth A.
name: Schachter, Joel B.
name: Guo, Danping
name: Kim, Yong-Chul
name: Harden, T. Kendall
name: Nicholas, Robert A.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 1997

description: We conducted a mutational analysis of residues potentially involved in the adenine nucleotide binding pocket of the human P2Y1 receptor. Mutated receptors were expressed in COS-7 cells with an epitope tag that permitted confirmation of expression in the plasma membrane, and agonist-promoted inositol phosphate accumulation was assessed as a measure of receptor activity. Residues in transmembrane helical domains (TMs) 3, 5, 6, and 7 predicted by molecular modeling to be involved in ligand recognition were replaced with alanine and, in some cases, by other amino acids. The potent P2Y1 receptor agonist 2-methylthio-ATP (2-MeSATP) had no activity in cells expressing the R128A, R310A, and S314A mutant receptors, and a markedly reduced potency of 2-MeSATP was observed with the K280A and Q307A mutants. These results suggest that residues on the exofacial side of TM3 and TM7 are critical determinants of the ATP binding pocket. In contrast, there was no change in the potency or maximal effect of 2-MeSATP with the S317A mutant receptor. Alanine replacement of F131, H132, Y136, F226, or H277 resulted in mutant receptors that exhibited a 7–18-fold reduction in potency compared with that observed with the wild-type receptor. These residues thus seem to subserve a less important modulatory role in ligand binding to the P2Y1 receptor. Because changes in the potency of 2-methylthio-ADP and 2-(hexylthio)-AMP paralleled the changes in potency of 2-MeSATP at these mutant receptors, the β- and γ-phosphates of the adenine nucleotides seem to be less important than the α-phosphate in ligand/P2Y1 receptor interactions. However, T221A and T222A mutant receptors exhibited much larger reductions in triphosphate (89- and 33-fold versus wild-type receptors, respectively) than in diphosphate or monophosphate potency. This result may be indicative of a greater role of these TM5 residues in γ-phosphate recognition. Taken together, the results suggest that the adenosine and α-phosphate moieties of ATP bind to critical residues in TM3 and TM7 on the exofacial side of the human P2Y1 receptor.
Mass - concentration relation and weak lensing peak counts
Creators: name: Cardone, V. F.
name: Camera, S.
name: Sereno, M.
name: Covone, G.
name: Maoli, R.
name: Scaramella, R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The statistics of peaks in weak lensing convergence maps is a promising tool to investigate both the properties of dark matter haloes and constrain the cosmological parameters. We study how the number of detectable peaks and its scaling with redshift depend upon the cluster dark matter halo profiles and use peak statistics to constrain the parameters of the mass - concentration (MC) relation. We investigate which constraints the Euclid mission can set on the MC coefficients also taking into account degeneracies with the cosmological parameters. To this end, we first estimate the number of peaks and its redshift distribution for different MC relations. We find that the steeper the mass dependence and the larger the normalisation, the higher is the number of detectable clusters, with the total number of peaks changing up to $40\%$ depending on the MC relation. We then perform a Fisher matrix forecast of the errors on the MC relation parameters as well as cosmological parameters. We find that peak number counts detected by Euclid can determine the normalization $A_v$, the mass $B_v$ and redshift $C_v$ slopes and intrinsic scatter $σ_v$ of the MC relation to an unprecedented accuracy being $σ(A_v)/A_v = 1\%$, $σ(B_v)/B_v = 4\%$, $σ(C_v)/C_v = 9\%$, $σ(σ_v)/σ_v = 1\%$ if all cosmological parameters are assumed to be known. Should we relax this severe assumption, constraints are degraded, but remarkably good results can be restored setting only some of the parameters or combining peak counts with Planck data. This precision can give insight on competing scenarios of structure formation and evolution and on the role of baryons in cluster assembling. Alternatively, for a fixed MC relation, future peaks counts can perform as well as current BAO and SNeIa when combined with Planck.
description: 14 pages, 8 figures, accepted for publication on Astronomy & Astrophysics
Quantitation of the P2Y1 Receptor with a High Affinity Radiolabeled Antagonist
Creators: name: Waldo, G. L.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2002

description: 2-Chloro-N6-methyl-(N)-methanocarba-2′-deoxyadenosine-3′,5′-bisphosphate (MRS2279) was developed previously as a selective high-affinity, non-nucleotide P2Y1 receptor (P2Y1-R) antagonist (J Med Chem 43:829–842, 2002; Br J Pharmacol 135:2004–2010, 2002). We have taken advantage of the N6-methyl substitution in the adenine base to incorporate [3H]methylamine into the synthesis of [3H]MRS2279 to high (89 Ci/mmol) specific radioactivity and have used this molecule as a radioligand for the P2Y1-R. [3H]MRS2279 bound to membranes from Sf9 insect cells expressing recombinant human P2Y1-R but not to membranes from wild-type Sf9 cells or Sf9 cells expressing high levels of recombinant P2Y2 or P2Y12 receptors. Equilibrium binding of [3H]MRS2279 to P2Y1-R expressed in Sf9 membranes was with a high affinity (Kd = 8 nM) essentially identical to the apparent affinity of MRS2279 determined previously in studies of P2Y1-R–promoted inositol phosphate accumulation or platelet aggregation. A kinetically derived Kd calculated from independent determinations of the rate constants of association (7.15 × 107 M−1 min−1) and dissociation (0.72 min−1) of [3H]MRS2279 also was in good agreement with the Kd derived from equilibrium binding studies. Competition binding assays with [3H]MRS2279 and P2Y1-R expressing Sf9 cell membranes revealed Ki values for the P2Y1-R antagonists MRS2279 (Ki = 13 nM), N6-methyl-2′-deoxyadenosine-3′,5′-bisphosphate (MRS2179; Ki = 84 nM), adenosine-3′, 5′-bisphosphate (Ki = 900 nM), and pyridoxal phosphate-6-azophenyl-2′,4′-disulfonic acid (Ki = 6 µM) that were in good agreement with antagonist activities of these molecules previously determined at the P2Y1-R in intact tissues. Moreover, [3H]MRS2279 also bound with high affinity (Kd = 4–8 nM) to Chinese hamster ovary (CHO) or 1321N1 human astrocytoma cells stably expressing the human P2Y1-R, but specific binding was not observed in wild-type CHO or 1321N1 cells. [3H]MRS2279 bound with high affinity (Kd = 16 nM) to a binding site on out-dated human platelets (5–35 receptors/platelet) and rat brain membranes (210 fmol/mg protein) that fit the expected drug selectivity of a P2Y1-R. Taken together, these results indicate that [3H]MRS2279 is the first broadly applicable antagonist radioligand for a P2Y receptor.
Analysis of Ghana’s Local Milk Value Chain: barriers to competitiveness
Creators: name: Boimah, M.
name: Gunarathne, A.
name: Behrendt, L.
name: Boimah, M.
name: Gunarathne, A.
name: Behrendt, L.
Publisher: name: Unknown
Year: 2021
Subjects: subject: International Relations/Trade
subject: Livestock Production/Industries
subject: Ghana
subject: value chain analysis
subject: dairy
subject: milk powder
subject: fresh milk

description: Ghana imports more milk and other dairy products yearly than it produces. Even for what is processed domestically, almost all are exclusively made from imported milk powder. It is in this regard that this study was initiated to analyze the barriers to the local dairy sector’s competitiveness employing both primary and secondary data sources. For the collection of primary data, in-depth interviews were conducted with key informants. A total of 34 actors along the local fresh milk and milk powder value chains were sampled and interviewed and the data descriptively analyzed. Results show that the local milk value chain of Ghana is informal, not developed and with minimal value addition to fresh milk compared to the value chain of imported milk powder. Moreover, local products sold on the Ghanaian markets do not undergo any form of safety tests and have not been approved by the regulatory and standard authorities. Further, a host of challenges along the local milk value chain are identified as factors limiting its competitiveness. Nevertheless, a window of opportunity for developing the local milk value chain is presented considering the growing demand for fresh milk-based dairy products in Ghana as well as increasing international trade to integrate into the Global Value Chain.
Conformational Variations of Both Phosphodiesterase-5 and Inhibitors Provide the Structural Basis for the Physiological Effects of Vardenafil and Sildenafil
Creators: name: Ke, H.
name: Robinson, H.
name: Wang, H.
name: Francis, S. H.
name: Ye, M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: Vardenafil has higher affinity to phosphodiesterase-5 (PDE5) than sildenafil and lower administered dosage for the treatment of erectile dysfunction. However, the molecular basis for these differences is puzzling because two drugs have similar chemical structures. Reported here is a crystal structure of the fully active and nonmutated PDE5A1 catalytic domain in complex with vardenafil. The structure shows that the conformation of the H-loop in the PDE5A1-vardenafil complex is different from those of any known structures of the unliganded PDE5 and its complexes with the inhibitors. In addition, the molecular configuration of vardenafil differs from that of sildenafil when bound to PDE5. It is noteworthy that the binding of vardenafil causes loss of the divalent metal ions that have been observed in all the previously published PDE structures. The conformational variation of both PDE5 and the inhibitors provides structural insight into the different potencies of the drugs.
Selective Killing of Smad4-Negative Tumor Cells via a Designed Repressor Strategy
Creators: name: Dixit, V.
name: Juliano, R. L.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: Smad4 is a key tumor suppressor that is frequently deleted or inactive in pancreatic and colon tumors. In this report we describe an approach for attaining selective killing of Smad4 deficient tumor cells. Using a vector system involving a designed repressor with zinc finger binding domains and the HSV-TK ‘suicide gene’, we demonstrate Smad4 responsive regulation of HSV-TK expression and consequent altered susceptibility to the pro-drug ganciclovir (GCV). In pancreatic tumor cell lines stably transfected with the vector system, a robust differential of HSV-TK expression and GCV toxicity was attained depending on the presence or absence of co-transfected Smad4. In matched colon tumor cell lines lacking Smad4 or expressing physiological levels of Smad4, an Adenoviral version of the vector system attained a significant degree of preferential killing of Smad4 negative tumor cells in response to GCV. These findings demonstrate the possibility of achieving selective killing of pancreatic and colon cells depending on their Smad4 status.
Structural Basis of Human Pregnane X Receptor Activation by the Hops Constituent Colupulone
Creators: name: Bischof, J. J.
name: Peng, L.
name: Redinbo, M. R.
name: Kliewer, S. A.
name: Teotico, D. G.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2008

description: Hops extracts are used to alleviate menopausal symptoms and as an alternative to hormone replacement therapy, but can produce potentially harmful drug-drug interactions. The nuclear xenobiotic receptor PXR is promiscuously activated by a range of structurally distinct chemicals. It has a key role in the transcriptional regulation of genes that encode xenobiotic metabolism enzymes. In this study, hops extracts are shown to induce the expression of numerous drug metabolism and excretion proteins. The β-bitter acid colupulone is demonstrated to be a bioactive component and direct activator of human PXR. The 2.8 Å resolution crystal structure of the ligand binding domain of human PXR in complex with colupulone was elucidated, and colupulone was observed to bind in a single orientation stabilized by both Van der Waals and hydrogen bonding contacts. The crystal structure also indicates that related α- and β-bitter acids have the capacity to serve as PXR agonists, as well. Taken together, these results reveal the structural basis for drug-drug interactions mediated by colupulone and related constituents of hops extracts.
Transitioning to Solar Energy in Thailand
Creators: name: Sereeyothin, Mudmee
Publisher: name: Unknown
Year: 2023
Subjects: subject: solar power
subject: solar farm
subject: renewable energy
subject: government incentives
subject: business
subject: economics
subject: climate
subject: natural resources

description: Mudmee Sereeyothin interviews Vinai Sereeyothin about renewable energy in Thailand. Sereeyothin reflects on his childhood in northeastern Thailand and working for his family's business, a fishing net company. He also discusses the company expanding into solar power in the 2010s, by building and maintaining a solar farm. Sereeyothin discusses the challenges of introducing solar energy to Thailand and how the country's climate and resources impact the farms. He also discusses making the switch from selling energy to the government to residential markets, along with reflecting on the affordability of the technology in Thailand. Sereeyothin predicts the expansion of renewable energy in the country.
An Allosteric Modulator of  7 Nicotinic Receptors, N-(5-Chloro-2,4-dimethoxyphenyl)-N'-(5-methyl-3-isoxazolyl)-urea (PNU-120596), Causes Conformational Changes in the Extracellular Ligand Binding Domain Similar to Those Caused by Acetylcholine
Creators: name: Richards, V. L.
name: See, J. A.
name: Rosenberg, R. L.
name: McLaughlin, J. T.
name: Barron, S. C.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2009

description: Nicotinic acetylcholine receptors are implicated in several neuropsychiatric disorders, including nicotine addiction, Alzheimer's, schizophrenia, and depression. Therefore, they represent a critical molecular target for drug development and targeted therapeutic intervention. Understanding the molecular mechanisms by which allosteric modulators enhance activation of these receptors is crucial to the development of new drugs. We used the substituted cysteine accessibility method to study conformational changes induced by the positive allosteric modulator N-(5-chloro-2,4-dimethoxyphenyl)-N′-(5-methyl-3-isoxazolyl)-urea (PNU-120596) in the extracellular ligand binding domain of α7 nicotinic receptors carrying the L247T mutation. PNU-120596 caused changes in cysteine accessibility at the inner beta sheet, transition zone, and agonist binding site. These changes in accessibility are similar to but not identical to those caused by ACh alone. In particular, PNU-120596 induced changes in MTSEA accessibility at N170C (in the transition zone) that were substantially different from those evoked by acetylcholine (ACh). We found that PNU-120596 induced changes at position E172C in the absence of allosteric modulation. We identified a cysteine mutation of the agonist binding site (W148C) that exhibited an unexpected phenotype in which PNU-120596 acts as a full agonist. In this mutant, ACh-evoked currents were more sensitive to thiol modification than PNU-evoked currents, suggesting that PNU-120596 does not bind at unoccupied agonist-binding sites. Our results provide evidence that binding sites for PNU-120596 are not in the agonist-binding sites and demonstrate that positive allosteric modulators such as PNU-120596 enhance agonist-evoked gating of nicotinic receptors by eliciting conformational effects that are similar but nonidentical to the gating conformations promoted by ACh.
Macroinvertebrate assemblages of littoral habitats in the Macquarie and Mersey Rivers, Tasmania: implications for the management of regulated rivers
Creators: name: Humphries, Paul
name: Davies, Peter E
name: Mulcahy, Mary E
Publisher: name: La Trobe
Year: 2023

description: Murray-Darling Freshwater Research Centre

MDFRC item.

Littoral habitats in large rivers are influenced to varying degrees by changes in discharge. Irrigation abstractions canincrease the amount of habitat that would naturally be dewatered during low flow periods and therefore it is importantto have some knowledge of the potential impact this may have on riverine macroinvertebrates. The macroinvertebrateassemblages of common littoral habitats in riffles, pools and runs in two reaches each of the Macquarie and MerseyRivers, northern Tasmania, Australia were compared from samples collected during the low flow and irrigation season,between December 1991 and April 1992. The area under water of these habitats, riffle substrata, macrophyte beds andcoarse woody debris, responded differently to changes in discharge. Within a reach, the same taxonomic groups oftendominated the total number of macroinvertebrates for all habitats, but there were differences in the proportionscontributed by these taxa to the different habitats. In general, taxa characteristic of slow-flowing or lentic habitats,such as ostracods and amphipods, were dominant in macrophyte beds in pools and runs, whereas taxa such as larvalelmid beetles and hydropsychid caddisflies were dominant in riffles. A substantial component of the fauna from eachhabitat within a reach was unique to that habitat, but there was always a similar number of taxa common to all habitats.Classification and ordination grouped samples from both rivers firstly by habitat and secondly by month and reach.Total density and family richness of invertebrates differed by reach, habitat and month in both rivers, except for richnessin the Mersey River where habitat was not significant. Differences in densities and numbers of invertebrate familiesamong habitats were not consistent between reaches for each river. This study has highlighted the differences inmacroinvertebrate assemblages of several littoral habitats in two lowland rivers in Tasmania. Differences in taxonomiccomposition, density and richness among habitats within reaches strongly imply the uniqueness of these habitats in termsof the invertebrate faunas that occupy them. We suggest that if maintenance of biotic diversity is an aim of instream flowmanagement, water allocations that address low flows should place a high priority on the maintenance of a diversity ofhabitats.
Caveolin-1 and Lipid Microdomains Regulate Gs Trafficking and Attenuate Gs/Adenylyl Cyclase Signaling
Creators: name: Roth, B. L.
name: Bhatnagar, A.
name: Dave, R. H.
name: Rasenick, M. M.
name: Allen, J. A.
name: Yu, J. Z.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2009

description: Lipid rafts and caveolae are specialized membrane microdomains implicated in regulating G protein-coupled receptor signaling cascades. Previous studies have suggested that rafts/caveolae may regulate β-adrenergic receptor/Gαs signaling, but underlying molecular mechanisms are largely undefined. Using a simplified model system in C6 glioma cells, this study disrupts rafts/caveolae using both pharmacological and genetic approaches to test whether caveolin-1 and lipid microdomains regulate Gs trafficking and signaling. Lipid rafts/caveolae were disrupted in C6 cells by either short-term cholesterol chelation using methyl-β-cyclodextrin or by stable knockdown of caveolin-1 and -2 by RNA interference. In imaging studies examining Gαs-GFP during signaling, stimulation with the βAR agonist isoproterenol resulted in internalization of Gαs-GFP; however, this trafficking was blocked by methyl-β-cyclodextrin or by caveolin knockdown. Caveolin knockdown significantly decreased Gαs localization in detergent insoluble lipid raft/caveolae membrane fractions, suggesting that caveolin localizes a portion of Gαs to these membrane microdomains. Methyl-β-cyclodextrin or caveolin knockdown significantly increased isoproterenol or thyrotropin-stimulated cAMP accumulation. Furthermore, forskolin- and aluminum tetrafluoride-stimulated adenylyl cyclase activity was significantly increased by caveolin knockdown in cells or in brain membranes obtained from caveolin-1 knockout mice, indicating that caveolin attenuates signaling at the level of Gαs/adenylyl cyclase and distal to GPCRs. Taken together, these results demonstrate that caveolin-1 and lipid microdomains exert a major effect on Gαs trafficking and signaling. It is suggested that lipid rafts/caveolae are sites that remove Gαs from membrane signaling cascades and caveolins might dampen globally Gαs/adenylyl cyclase/cAMP signaling.
Li intercalation in graphite: a van der Waals density-functional study
Creators: name: Hazrati, E.
name: de Wijs, G. A.
name: Brocks, G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Modeling layered intercalation compounds from first principles poses a problem, as many of their properties are determined by a subtle balance between van der Waals interactions and chemical or Madelung terms, and a good description of van der Waals interactions is often lacking. Using van der Waals density functionals we study the structures, phonons and energetics of the archetype layered intercalation compound Li-graphite. Intercalation of Li in graphite leads to stable systems with calculated intercalation energies of $-0.2$ to $-0.3$~eV/Li atom, (referred to bulk graphite and Li metal). The fully loaded stage 1 and stage 2 compounds LiC$_6$ and Li$_{1/2}$C$_6$ are stable, corresponding to two-dimensional $\sqrt3\times\sqrt3$ lattices of Li atoms intercalated between two graphene planes. Stage $N>2$ structures are unstable compared to dilute stage 2 compounds with the same concentration. At elevated temperatures dilute stage 2 compounds easily become disordered, but the structure of Li$_{3/16}$C$_6$ is relatively stable, corresponding to a $\sqrt7\times\sqrt7$ in-plane packing of Li atoms. First-principles calculations, along with a Bethe-Peierls model of finite temperature effects, allow for a microscopic description of the observed voltage profiles.
description: 12 pages, 6 figures