750 research outputs found
The cardiovascular implications of omega-3 fatty acids
Nutrition is an important factor in the primary and secondary prevention of cardiovascular disease. Cardiovascular disease is the leading cause of death in North America and the world. Observational studies have generally favoured a beneficial role of n-3 fatty acids in the prevention of heart disease, especially in the prevention of sudden cardiac death. The results of more recent randomised controlled studies, however, have made conclusions regarding the benefit more controversial, with the suggestion of possible harm with fish oil supplementation to those with diagnosed cardiovascular disease.
We provide an overview of the results of studies to date and introduce the controversial topics of the omega-6/omega-3 ratio, the public’s concerns regarding ingestion of mercury from marine n-3 sources and the potential role of highly bioactive n-3 metabolites in the process of atherosclerosis. We also provide some general guidelines for the ingestion of n-3 fatty acids that may help clinicians and patients make informed decisions
Novel therapeutic targets for preserving a healthy endothelium: Strategies for reducing the risk of vascular and cardiovascular disease
The endothelium lies in a strategic anatomical position between the circulating blood and the
vascular smooth-muscle cells. It is a source of vasodilators such as nitric oxide, prostacyclin,
and hyperpolarizing factor as well as heparin-like substances and other molecules with antiproliferative
properties. These effects of endothelial cells may explain why platelets and
monocytes usually do not adhere at the blood vessel wall. However, under pathological conditions,
endothelial dysfunction occurs and significantly contributes to the increase of platelet-
-vessel wall interaction, vasoconstriction, pro-inflammation, and proliferation. Under these
conditions, endothelium-dependent vasodilation is reduced, and endothelium-dependent constrictor
responses are augmented. Upon vessel wall injury, the platelets rapidly adhere to the
exposed sub-endothelial matrix, which is mediated by several cellular receptors present on
platelets or endothelial cells and various adhesive proteins. Subsequent platelet activation
results in the recruitment of additional platelets and the generation of platelet aggregates, so
forming a stable platelet plug. Therapeutic strategies aimed at improving or preserving endothelial
function therefore may be promising in terms of preventing and treating coronary
artery disease. Diagnostic modalities for assessing endothelial function should allow for the
early detection of vascular endothelial dysfunction before the manifestation of serious adverse
vascular disorders. (Cardiol J 2011; 18, 4: 352–363
The Building of Galactic Disks: Insights from the Triangulum Spiral Galaxy Messier 33
The Triangulum Spiral Galaxy Messier 33 offers unique insights into the
building of a galactic disk. We identify spectacular arcs of intermediate age
(0.6 Gyr - 2 Gyr) stars in the low-metallicity outer disk. The northern arc
spans approx. 120 degrees in azimuth and up to 5 arcmin in width. The arcs are
located 2-3 disk scale lengths from the galaxy centre (where 1 disk scale
length is equivalent to 0.1 degrees in the V-band) and lie precisely where
there is a warp in the HI profile of M33. Warps and infall are inextricably
linked (Binney, 1992). We present spectroscopy of candidate stars in the outer
northern arc, secured using the Keck I telescope in Hawaii. The target stars
have estimated visual magnitudes as faint as V ~ 25m. Absorption bands of CN
are seen in all spectra reported in this review talk, confirming their carbon
star status. Also presented are PAH emissivity radial profiles generated from
IRAC observations of M33 using the Spitzer Space Telescope. A dramatic change
of phase in the m=2 Fourier component is detected at the domain of the arcs.
M33 serves as an excellent example how the disks of spiral galaxies in our
Universe are built: as dynamically open systems, growing from the inward,
outward.Comment: Invited review paper presented at IAU Simposium 235, Galaxy Evolution
Across the Hubble Time, Prague. To be published by Cambridge University
Press, eds. F. Combes & J. Palou
Wpływ kwasów tłuszczowych omega-3 na układ sercowo-naczyniowy
Sposób odżywiania jest ważnym czynnikiem w pierwotnej i wtórnej prewencji chorób sercowo-naczyniowych, które stanowią główny powód zgonów w Ameryce Północnej i na świecie.
W badaniach obserwacyjnych dotyczących roli kwasów tłuszczowych omega-3 w prewencji tych
schorzeń wykazano ogólnie korzystny wpływ kwasów omega-3, szczególnie w przypadku prewencji
nagłej śmierci sercowej. Jednak w późniejszych randomizowanych badaniach korzystne
wyniki okazały się bardziej kontrowersyjne, z sugestią możliwych niekorzystnych skutków
suplementacji olejów rybnych u osób z rozpoznaną chorobą sercowo-naczyniową.
W niniejszej pracy przedstawiono przegląd wyników dotychczasowych badań oraz zaprezentowano
kontrowersyjne zagadnienia, takie jak wskaźnik omega-6/omega-3, obawy dotyczące spożywania
rtęci z pochodzących z morza źródeł kwasów n-3 oraz potencjalna rola biologicznie wysoko
aktywnych metabolitów n-3 w procesie miażdżycy naczyń. Przedstawiono także ogólne zalecenia
dotyczące spożycia kwasów tłuszczowych n-3 mogące pomóc klinicystom i pacjentom w podejmowaniu
właściwych decyzji
UV-Optical Pixel Maps of Face-On Spiral Galaxies -- Clues for Dynamics and Star Formation Histories
UV and optical images of the face-on spiral galaxies NGC 6753 and NGC 6782
reveal regions of strong on-going star formation that are associated with
structures traced by the old stellar populations. We make NUV--(NUV-I) pixel
color-magnitude diagrams (pCMDs) that reveal plumes of pixels with strongly
varying NUV surface brightness and nearly constant I surface brightness. The
plumes correspond to sharply bounded radial ranges, with (NUV-I) at a given NUV
surface brightness being bluer at larger radii. The plumes are parallel to the
reddening vector and simple model mixtures of young and old populations, thus
neither reddening nor the fraction of the young population can produce the
observed separation between the plumes. The images, radial surface-brightness,
and color plots indicate that the separate plumes are caused by sharp declines
in the surface densities of the old populations at radii corresponding to disk
resonances. The maximum surface brightness of the NUV light remains nearly
constant with radius, while the maximum I surface brightness declines sharply
with radius. An MUV image of NGC 6782 shows emission from the nuclear ring. The
distribution of points in an (MUV-NUV) vs. (NUV-I) pixel color-color diagram is
broadly consistent with the simple mixture model, but shows a residual trend
that the bluest pixels in (MUV-NUV) are the reddest pixels in (NUV-I). This may
be due to a combination of red continuum from late-type supergiants and [SIII]
emission lines associated with HII regions in active star-forming regions. We
have shown that pixel mapping is a powerful tool for studying the distribution
and strength of on-going star formation in galaxies. Deep, multi-color imaging
can extend this to studies of extinction, and the ages and metallicities of
composite stellar populations in nearby galaxies.Comment: LaTeX with AASTeX style file, 29 pages with 12 figures (some color,
some multi-part). Accepted for publication in The Astrophysical Journa
Observing System Simulation Experiment (OSSE) for the HyspIRI Spectrometer Mission
The OSSE software provides an integrated end-to-end environment to simulate an Earth observing system by iteratively running a distributed modeling workflow based on the HyspIRI Mission, including atmospheric radiative transfer, surface albedo effects, detection, and retrieval for agile exploration of the mission design space. The software enables an Observing System Simulation Experiment (OSSE) and can be used for design trade space exploration of science return for proposed instruments by modeling the whole ground truth, sensing, and retrieval chain and to assess retrieval accuracy for a particular instrument and algorithm design. The OSSE in fra struc ture is extensible to future National Research Council (NRC) Decadal Survey concept missions where integrated modeling can improve the fidelity of coupled science and engineering analyses for systematic analysis and science return studies. This software has a distributed architecture that gives it a distinct advantage over other similar efforts. The workflow modeling components are typically legacy computer programs implemented in a variety of programming languages, including MATLAB, Excel, and FORTRAN. Integration of these diverse components is difficult and time-consuming. In order to hide this complexity, each modeling component is wrapped as a Web Service, and each component is able to pass analysis parameterizations, such as reflectance or radiance spectra, on to the next component downstream in the service workflow chain. In this way, the interface to each modeling component becomes uniform and the entire end-to-end workflow can be run using any existing or custom workflow processing engine. The architecture lets users extend workflows as new modeling components become available, chain together the components using any existing or custom workflow processing engine, and distribute them across any Internet-accessible Web Service endpoints. The workflow components can be hosted on any Internet-accessible machine. This has the advantages that the computations can be distributed to make best use of the available computing resources, and each workflow component can be hosted and maintained by their respective domain experts
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