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Search Results: 1 - 10 of 463310 matches for " Glenn A. Jacobson "
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Albuterol enantiomer levels, lung function and QTc interval in patients with acute severe asthma and COPD in the emergency department
Kwang Yee, Glenn A Jacobson, Richard Wood-Baker, E Haydn Walters
International Journal of Emergency Medicine , 2011, DOI: 10.1186/1865-1380-4-30
Abstract: Blood samples were collected and plasma/serum levels of (R)- and (S)-albuterol enantiomers were determined by LC-MS and LC-MS/MS assay. Extra-pulmonary effects measured at presentation included ECG measurements, serum potassium level and blood sugar level, which were collected from the hospital medical records.High plasma levels of both enantiomers were observed in some individuals, with median (range) concentrations of 8.2 (0.6-24.8) and 20.6 (0.5-57.3) ng/mL for (R)- and (S)- albuterol respectively among acute asthma subjects, and 2.1 (0.0-16.7) to 4.1 (0.0-36.1) ng/mL for (R)- and (S)- albuterol respectively among COPD subjects. Levels were not associated with an improvement in lung function or adverse cardiac effects (prolonged QTc interval).High plasma concentrations of albuterol were observed in both asthma and COPD patients presenting to the emergency department. Extra-pulmonary cardiac adverse effects (prolonged QTC interval) were not associated with the plasma level of (R)- or (S)-albuterol when administered by inhaler in the emergency department setting. Long-term effect(s) of continuous high circulating albuterol enantiomer concentrations remain unknown, and further investigations are required.Albuterol (salbutamol), a β2-agonist, plays an important role in emergency medicine and is the first line medication for relief of shortness of breath during acute asthma exacerbations. Albuterol is also used on a regular basis for the management of chronic obstructive pulmonary disease (COPD), both during stable periods and acute exacerbations [1-3]. Many recent studies and guidelines have indicated that the use of short-acting β2-agonists on a regular basis will not improve asthma control, and may even cause deterioration [4-6]. However, regular use of short-acting β2-agonists such as albuterol is still very common for the management of COPD [1-3].Albuterol is a chiral compound consisting of (R)- and (S)- enantiomers, and is most commonly administered as a 1:1 rac
Effects of Heparin and Enoxaparin on APP Processing and Aβ Production in Primary Cortical Neurons from Tg2576 Mice
Hao Cui, Amos C. Hung, David W. Klaver, Toshiharu Suzuki, Craig Freeman, Christian Narkowicz, Glenn A. Jacobson, David H. Small
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023007
Abstract: Background Alzheimer's disease (AD) is caused by accumulation of Aβ, which is produced through sequential cleavage of β-amyloid precursor protein (APP) by the β-site APP cleaving enzyme (BACE1) and γ-secretase. Enoxaparin, a low molecular weight form of the glycosaminoglycan (GAG) heparin, has been reported to lower Aβ plaque deposition and improve cognitive function in AD transgenic mice. Methodology/Principal Findings We examined whether heparin and enoxaparin influence APP processing and inhibit Aβ production in primary cortical cell cultures. Heparin and enoxaparin were incubated with primary cortical cells derived from Tg2576 mice, and the level of APP and proteolytic products of APP (sAPPα, C99, C83 and Aβ) was measured by western blotting. Treatment of the cells with heparin or enoxaparin had no significant effect on the level of total APP. However, both GAGs decreased the level of C99 and C83, and inhibited sAPPα and Aβ secretion. Heparin also decreased the level of β-secretase (BACE1) and α-secretase (ADAM10). In contrast, heparin had no effect on the level of ADAM17. Conclusions/Significance The data indicate that heparin and enoxaparin decrease APP processing via both α- and β-secretase pathways. The possibility that GAGs may be beneficial for the treatment of AD needs further study.
Do CD4+ T Cell Functional Responses to Epstein–Barr Virus Provide Protective Immunity Against CNS Lymphoma in AIDS?
Mark A Jacobson
PLOS Medicine , 2007, DOI: 10.1371/journal.pmed.0040110
Abstract:
Introduction to Black Hole Microscopy
Theodore A. Jacobson
Physics , 1995,
Abstract: The aim of these notes is both to review the standard understanding of the Hawking effect, and to discuss the modifications to this understanding that might be required by new physics at short distances. The fundamentals of the Unruh effect are reviewed, and then the Hawking effect is explained as a ``gravitational Unruh effect", with particular attention to the state-dependence of this picture. The order of magnitude of deviations from the thermal spectrum of Hawking radiation is estimated under various hypotheses on physics at short distances. The behavior of black hole radiation in a linear model with altered short distance physics---the Unruh model---is discussed in detail. [Based on lectures given at the First Mexican School on Gravitation and Mathematical Physics, Guanajuato, December 1994.]
Small asteroid system evolution
Seth A. Jacobson
Physics , 2014, DOI: 10.1017/S174392131400800X
Abstract: Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structure. We review our current understanding of how small asteroid systems evolve and point to the future.
Multiple origins of asteroid pairs
Seth A. Jacobson
Physics , 2015,
Abstract: Rotationally fissioned asteroids produce unbound daughter asteroids that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have high mass ratios with possibly fast rotating primaries. However, secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.
From the global signature to higher signatures
Jeremy A. Jacobson
Mathematics , 2014,
Abstract: Let $X$ be an algebraic variety over the field of real numbers $\mathbb{R}$. We use the signature of a quadratic form to produce "higher" global signatures relating the derived Witt groups of $X$ to the singular cohomology of the real points $X(\mathbb{R})$ with integer coefficients. We also study the global signature ring homomorphism and use the powers of the fundamental ideal in the Witt ring to prove an integral version of a theorem of Raman Parimala and Jean Colliot-Thelene on the mod 2 signature. Furthermore, we obtain an Atiyah-Hirzebruch spectral sequence for the derived Witt groups of $X$ with 2 inverted. Using this spectral sequence, we provide a bound on the ranks of the derived Witt groups of $X$ in terms of the Betti numbers of $X(\mathbb{R})$. We apply our results to answer a question of Max Karoubi on boundedness of torsion in the Witt group of $X$. Throughout the article, the results are proved for a wide class of schemes over an arbitrary base field of characteristic different from 2 using real cohomology in place of singular cohomology.
Observations of atmospheric gravity waves by radio interferometry: are results biased by the observational technique?
C. Mercier,A. R. Jacobson
Annales Geophysicae (ANGEO) , 2003,
Abstract: In this paper we present a quantitative comparison between a large data base of medium-scale atmospheric gravity waves (AGWs) observed by radio interferometry of transionospheric radio sources and the results of a numerical simulation of the observed effects. The simulation includes: (i) the propagation and dissipation of AGWs up to ionospheric heights and (ii) the calculation of the subsequent slant TEC perturbations integrated along the path to the radio sources. We show that the observed azimuthal distribution of AGWs can be deeply biased. Predicted results are found to be consistent with previous extensive observations using radio beacons aboard geostationary satellites. These observations are rediscussed in view of the present predictions.
Lunar and Terrestrial Planet Formation in the Grand Tack Scenario
Seth A. Jacobson,Alessandro Morbidelli
Physics , 2014, DOI: 10.1098/rsta.2013.0174
Abstract: We present conclusions from a large number of N-body simulations of the giant impact phase of terrestrial planet formation. We focus on new results obtained from the recently proposed Grand Tack model, which couples the gas-driven migration of giant planets to the accretion of the terrestrial planets. The giant impact phase follows the oligarchic growth phase, which builds a bi-modal mass distribution within the disc of embryos and planetesimals. By varying the ratio of the total mass in the embryo population to the total mass in the planetesimal population and the mass of the individual embryos, we explore how different disc conditions control the final planets. The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon forming) impact and its violence. The initial embryo mass sets the size of the lunar impactor and the growth rate of Mars. After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) and taking into account independent geochemical constraints on the mass accreted by the Earth after the Moon forming event and on the timescale for the growth of Mars, we conclude that the protoplanetary disc at the beginning of the giant impact phase must have had most of its mass in Mars-sized embryos and only a small fraction of the total disc mass in the planetesimal population. From this, we infer that the Moon forming event occurred between $\sim$60 and $\sim$130 My after the formation of the first solids, and was caused most likely by an object with a mass similar to that of Mars.
Civic Engagement in Higher Education: Concepts and Practices
Glenn A. Bowen
Partnerships : A Journal of Service-Learning and Civic Engagement , 2012, DOI: 10.7253/partj.v0i0.436
Abstract: As the new millennium dawned, it became clear that American higher education had done some serious soul-searching in light of concerns that it was losing distinctiveness in pursuit of prestige. Moreover, many institutions began returning to their roots in response to exhortations to take a new leadership role in preparing students for active, responsible citizenship. Ernest Boyer struck a responsive chord when he proposed the scholarship of engagement as a means whereby the academy would employ its considerable resources to tackle the social, civic, and ethical problems that beset our communities (Boyer, 1996). In 1999, higher education leaders across the country articulated their commitment to the civic purposes of their institutions as vital agents and architects of a flourishing democracy (Campus Compact, 2000). The present decade has witnessed a widespread renewal of higher education’s historical commitment to public engagement and the growth of service-learning as a pedagogical approach to developing civic knowledge and skills. However, much work remains to be done. Social problems persist, locally and globally; today’s youth view political involvement with skepticism; civic learning is lacking, or lagging. That is the basis of Civic Engagement in Higher Education: Concepts and Practices.
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