2,763 research outputs found
The effects of anatabine on non-invasive indicators of muscle damage: a randomized, double-blind, placebo-controlled, crossover study
Background: Anatabine (ANA), a minor tobacco alkaloid found in the Solanaceae family of plants, may exhibit anti-inflammatory activity, which may be useful to aid in recovery from exercise-induced muscle damage. The purpose of this study, therefore, was to examine the effects of ANA supplementation on the recovery of isometric strength and selected non-invasive indicators of muscle damage.
Methods: A double-blinded, placebo-controlled, crossover design was used to study eighteen men (mean ± SD age = 22.2 ± 3.1 yrs; body mass = 80.3 ± 15.7 kg) who participated in two randomly-ordered conditions separated by a washout period. The ANA condition consisted of consuming 6–12 mg anatabine per day for 10 days, while testing took place during days 7–10. The placebo (PLA) condition was identical except that the PLA supplement contained no ANA. Maximal voluntary isometric peak torque (PT) of the forearm flexors, arm circumference, hanging joint angle, and subjective pain ratings were measured before (PRE), immediately after (POST), and 24, 48, and 72 h after six sets of 10 maximal, eccentric isokinetic forearm flexion muscle actions. Resting heart rate and blood pressure were measured at PRE and 72 h in each condition.
Results: For PT, hanging joint angle, arm circumference, and subjective pain ratings, there were no condition x time (p \u3e 0.05) interactions, there were no main effects for condition (p \u3e 0.05), but there were main effects for time (p \u3c 0.001). There were no condition x time (p \u3e 0.05) interactions and no main effects for condition (p \u3e 0.05) or time (p \u3e 0.05) for blood pressure or resting heart rate.
Conclusions: ANA supplementation had no effect on the recovery of muscle strength, hanging joint angle, arm swelling, or subjective pain ratings after a bout of maximal eccentric exercise in the forearm flexors. Therefore, ANA may not be beneficial for those seeking to improve recovery from heavy eccentric exercise. Future studies should examine the effects of ANA on the pro-inflammatory cytokine responses to exercise-induced muscle damage and the chronic low-grade inflammation observed in obese and elderly individuals
Buffer layer-assisted growth of Ge nanoclusters on Si
In the buffer layer-assisted growth method, a condensed inert gas layer of xenon, with low-surface free energy, is used as a buffer to prevent direct interactions of deposited atoms with substrates. Because of␣an unusually wide applicability, the buffer layer-assisted growth method has provided a unique avenue for creation of nanostructures that are otherwise impossible to grow, and thus offered unprecedented opportunities for fundamental and applied research in nanoscale science and technology. In this article, we review recent progress in the application of the buffer layer-assisted growth method to the fabrication of Ge nanoclusters on Si substrates. In particular, we emphasize the novel configurations of the obtained Ge nanoclusters, which are characterized by the absence of a wetting layer, quasi-zero dimensionality with tunable sizes, and high cluster density in comparison with Ge nanoclusters that are formed with standard Stranski-Krastanov growth methods. The optical emission behaviors are discussed in correlation with the morphological properties
Early Inception of the Laramide Orogeny in Southwestern Montana and Northern Wyoming: Implications for Models of Flat‐Slab Subduction
Timing and distribution of magmatism, deformation, exhumation, and basin development have been used to reconstruct the history of Laramide flat-slab subduction under North America during Late Cretaceous-early Cenozoic time. Existing geodynamic models, however, ignore a large (40,000-km(2)) sector of the Laramide foreland in southwestern Montana. The Montana Laramide ranges consist of Archean basement arches (fault-propagation folds) that were elevated by thrust and reverse faults. We present new thermochronological and geochronological data from six Laramide ranges in southwestern Montana (the Beartooth, Gravelly, Ruby and Madison Ranges, and the Tobacco Root and Highland Mountains) that show significant cooling and exhumation during the Early to mid-Cretaceous, much earlier than the record of Laramide exhumation in Wyoming. These data suggest that Laramide-style deformation-driven exhumation slightly predates the eastward sweep of magmatism in western Montana, consistent with geodynamic models involving initial strain propagation into North American cratonic rocks due to stresses associated with a northeastward expanding region of flat-slab subduction. Our results also indicate various degrees of Cenozoic heating and cooling possibly associated with westward rollback of the subducting Farallon slab, followed by Basin-and-Range extension. Plain Language Summary The Laramide region in the western U.S. is characterized by some of the highest topography in North America including the Wind River Range in WY and the Beartooth Range of WY and Montana. These ranges have fed detritus to surrounding basins for millions of years and contributed to modern ecosystems. These high topographic features and basins have significantly impacted paleoenvironmental conditions over geological time. The formation of these high-relief ranges has been linked to deep Earth, geodynamic, processes involving subduction of a flat slab under the North American Plate. Models of flat-slab subduction rely on the timing and pattern of deformation and exhumation of Laramide ranges, which remains poorly understood. Our study provides new data on the timing of deformation and exhumation of Laramide ranges in SW Montana and northern WY capable of testing current models of flat-slab subduction.NSF-Tectonics [EAR-1524151]6 month embargo; published online: 9 January 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Eastern Pacific Warm Pool paleosalinity and climate variability : 0–30 kyr
Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 21 (2006): PA3008, doi:10.1029/2005PA001208.Multi-proxy geologic records of δ18O and Mg/Ca in fossil foraminifera from
sediments under the Eastern Pacific Warm Pool (EPWP) region west of Central America
document variations in upper ocean temperature, pycnocline strength, and salinity (i.e., net precipitation) over the past 30 ky. Although evident in the paleotemperature record,
there is no glacial-interglacial difference in paleosalinity, suggesting that tropical
hydrologic changes do not respond passively to high-latitude ice sheets and oceans.
Millennial variations in paleosalinity with amplitudes as high as ~4 PSU occur with a
dominant period of ~3-5 ky during the glacial/deglacial interval and ~1.0-1.5 ky during the Holocene. The amplitude of the EPWP paleosalinity changes greatly exceeds that of published Caribbean and western tropical Pacific paleosalinity records. EPWP
paleosalinity changes correspond to millennial-scale climate changes in the surface and
deep Atlantic and the high northern latitudes, with generally higher (lower) paleosalinity during cold (warm) events. In addition to Intertropical Convergence Zone (ITCZ) dynamics, which play an important role in tropical hydrologic variability, changes in Atlantic-Pacific moisture transport, which is closely linked to ITCZ dynamics, may also
contribute to hydrologic variations in the EPWP. Calculations of interbasin salinity
average and interbasin salinity contrast between the EPWP and the Caribbean help
differentiate long-term changes in mean ITCZ position and Atlantic-Pacific moisture
transport, respectively.Support for this research was provided by the U.S. National Science Foundation
Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron
The combination of searches performed by the CDF and D0 collaborations at the
Fermilab Tevatron Collider for neutral Higgs bosons produced in association
with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated
luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states
containing three or more b jets. Upper limits are set on the cross section
multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs
boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson.
Significant enhancements to the production of Higgs bosons can be found in
theories beyond the standard model, for example in supersymmetry. The results
are interpreted as upper limits in the parameter space of the minimal
supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
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