167,884 research outputs found
Ligand-Specific Regulation of the Endogenous Mu-Opioid Receptor by Chronic Treatment with Mu-Opioid Peptide Agonist
No full textSince the discovery of the endomorphins (EM), the postulated endogenous peptide agonists of the mu-opioid receptors, several analogues have been synthesized to improve their binding and pharmacological profiles. We have shown previously that a new analogue, cis-1S,2R-aminocyclohexanecarboxylic acid2-endomorphin-2 (ACHC-EM2), had elevated mu-receptor affinity, selectivity, and proteolytic stability over the parent compound. In the present work, we have studied its antinociceptive effects and receptor regulatory processes. ACHC-EM2 displayed a somewhat higher (60%) acute antinociceptive response than the parent peptide, EM2 (45%), which peaked at 10 min after intracerebroventricular (icv) administration in the rat tail-flick test. Analgesic tolerance developed to the antinociceptive effect of ACHC-EM2 upon its repeated icv injection that was complete by a 10-day treatment. This was accompanied by attenuated coupling of mu-sites to G-proteins in subcellular fractions of rat brain. Also, the density of mu-receptors was upregulated by about 40% in the light membrane fraction, with no detectable changes in surface binding. Distinct receptor regulatory processes were noted in subcellular fractions of rat brains made tolerant by the prototypic full mu-agonist peptide, DAMGO, and its chloromethyl ketone derivative, DAMCK. These results are discussed in light of the recently discovered phenomenon, that is, the “so-called biased agonism” or “functional selectivity
Probing the effect of author self-citations on h index: A case study of environmental engineering
No full textThis study evaluates the impact of author self-citations on h index by exploring 583 authors whose works appear in key periodicals in environmental engineering. The findings show that authors’ h values have high correlation with authors’ article number, total cited count, and their rankings. There is also a high correlation with h index values and rankings of h values. The study indicates that selfcitations have little impact on the values of h index and the h index rankings, whether or not articles with authors’ self-citation are included. Further investigations reveal that, for authors with high values in h index, the two h index values are both highly correlated and with significant difference either with self-citations or without. A similar pattern is seen in authors with low h values. The results suggest that there is no need to deliberately exclude self-citations in analysing or evaluating research performance in environmental engineering.國外SSCIY電子版紙本GB
EXPTIME Tableaux for the Coalgebraic Mu-Calculus
No full textThe coalgebraic approach to modal logic provides a uniform framework that captures the semantics of a large class of structurally different modal logics, including e.g. graded and probabilistic modal logics and coalition logic. In this paper, we introduce the coalgebraic mu-calculus, an extension of the general (coalgebraic) framework with fixpoint operators. Our main results are completeness of the associated tableau calculus and EXPTIME decidability. Technically, this is achieved by reducing satisfiability to the existence of non-wellfounded tableaux, which is in turn equivalent to the existence of winning strategies in parity games. Our results are parametric in the underlying class of models and yield, as concrete applications, previously unknown complexity bounds for the probabilistic mu-calculus and for an extension of coalition logic with fixpoints
Free radicals formed by H(Mu) addition to fluoranthene
No full textMuonium has been used as an H atom analogue to investigate the free radicals formed by H addition to the polyaromatic hydrocarbon fluoranthene. There are nine unique carbons in the molecule, but only five radicals were detected. Muon and proton hyperfine constants were determined by transverse field µSR and µLCR, respectively, and compared with calculated values. All signals were assigned to radicals formed by Mu addition to C-H sites. There isno evidence for addition to the tertiary carbons at ring junctions.Peer reviewedFinal article publishe
Estimation of evapotranspiration in the Mu Us Sandland of China
No full textEvapotranspiration (ET) was estimated from 1981–2005 over Wushen County located in the Mu Us Sandland, China, by applying the Advection-Aridity model, which is based on the complementary relationship hypothesis. We used National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological data. Our results show that the estimated daily ET was about 4.5% higher than measurements using an Eddy Covariance (EC) system after forcing energy balance closure over an alfalfa field from 22 July 2004 to 23 August 2004. At a regional scale, the estimated monthly ET was about 8.7% lower than measurements using the EC system after forcing energy balance closure over an alfalfa field in August 2004. These results were about 3.0% higher than ET measurements by microlysimeter over sand dunes during June 1988. From 1981 to 2005, the average annual ET and precipitation levels were 287 mm and 336 mm, respectively, in Wushen County. The average annual ET varied from 230 mm in western parts of Wushen County to 350 mm in eastern parts of the county. Both inter-annual and seasonal variations in ET were substantial in Wushen County. The annual ET was 200–400 mm from 1981–2005, and the seasonal pattern of ET showed a single peak distribution. The cumulative ET during the June–September 2004 period was 250 mm, which was 87% of the total annual ET. The annual ET, precipitation, and the maximum Normalized Difference Vegetation Index (NDVI<sub>max</sub>) showed positive correlations temporally and spatially
Synergistic Activation of Amides and Hydrocarbons for Direct C(sp3)–H Acylation Enabled by Metallaphotoredox Catalysis
No full text© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimThe utilizations of omnipresent, thermodynamically stable amides and aliphatic C(sp3)−H bonds for various functionalizations are ongoing challenges in catalysis. In particular, the direct coupling between the two functional groups has not been realized. Here, we report the synergistic activation of the two challenging bonds, the amide C−N and unactivated aliphatic C(sp3)−H, via metallaphotoredox catalysis to directly acylate aliphatic C−H bonds utilizing amides as stable and readily accessible acyl surrogates. N-acylsuccinimides served as efficient acyl reagents for the streamlined synthesis of synthetically useful ketones from simple C(sp3)−H substrates. Detailed mechanistic investigations using both computational and experimental mechanistic studies were performed to construct a detailed and complete catalytic cycle. The origin of the superior reactivity of the N-acylsuccinimides over other more reactive acyl sources such as acyl chlorides was found to be an uncommon reaction pathway which commences with C−H activation prior to oxidative addition of the acyl substrate11sciescopu
Computer simulation of a-Si : H/mu c-Si : H diphasic silicon solar cells
No full textBased on our experimental research on diphasic silicon films, the parameters such as absorption coefficient, mobility lifetime product and bandgap were estimated by means of effective-medium theory. And then computer simulation of a-Si: H/mu c-Si: H diphasic thin film solar cells was performed. It was shown that the more crystalline fraction in the diphasic silicon films, the higher short circuit density, the lower open-circuit voltage and the lower efficiency. From the spectral response, we can see that the response in long wave region was improved significantly with increasing crystalline fraction in the silicon films. Taking Lambertian back refraction into account, the diphasic silicon films with 40%-50% crystalline fraction was considered to be the best intrinsic layer for the bottom solar cell in micromorph tandem
Study of H, A -> mu+mu- in CMS
No full textSUSY Higgs decays to muons, H, A -> mu+mu- are studied. Discovery limits as a function of m( A) and tan( beta) are calculated, for the inclusive H, A -> mu+mu- channel, and for the associated channels bbH( SUSY), H( SUSY) -> mu+mu-. The latter is investigated including tagging of b-jets with the impact parameter method
Search for pair production of doubly charged Higgs bosons in the H++H--->mu(+)mu(+)mu(-)mu(-) final state
No full textWe report the results of a search for pair production of doubly charged Higgs bosons via p (p) over bar -> H++H--X ->mu(+)mu(+)mu(-)mu X- at root s=1.96 TeV. We use a data set corresponding to an integrated luminosity of 1.1 fb(-1) collected from 2002 to 2006 by the D0 detector at the Fermilab Tevatron Collider. In the absence of an excess above the standard model background, lower mass limits of M(H-L(+/-+/-))> 150 GeV/c(2) and M(H-R(+/-+/-))> 127 GeV/c(2) at 95% C.L. are set, respectively, for left-handed and right-handed doubly charged Higgs bosons assuming a 100% branching ratio into muons.AuthorOverflow(533
Theoretical investigation of the metal-metal interaction in dimolybdenum complexes with bridging hydride and methyl ligands
No full textDFT calculations on dinuclear molybdenum complexes with bridging hydride and methyl ligands, namely [CpMo(mu-O2CH)](2)(mu-PH2)(mu-H) and [CP*MO(mu-O2CMe)](2)(mu-PMe2)(mu-Me), indicate that the bonding is best described in terms of. (i) a 2-center-2-electron Mo-Mo single bond and (ii) a 3-center-2-electron Mo-H-Mo or Mo-Me-Mo bond. The presence of a 2-center-2-electron Mo-Mo single bond is in accord with an electron counting procedure that views the bridging hydride and methyl ligands as mu-LX ligands; in contrast, an electron counting procedure which apportions half of the valence electron of the hydrogen atom or methyl radical to each metal dictates a Mo=Mo double bond, a result that is contrary to the theoretical calculations. Consideration of a variety of other bridging hydride complexes indicates that the mu-LX electron counting method provides the best general description of the bonding by clearly distinguishing between the number of 3-center-2-electron M-H-M interactions and direct 2-center-2-electron M-M interactions. (C) 2004 Elsevier Ltd. All rights reserved
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