387 research outputs found
Plasma Cholesterol Ester Fatty Acids: A New Biochemical Abnormality in Obstructive Jaundice
Changes in fatty acid patterns may explain many of the observed abnormalities found in
obstructive jaundice. This study looked at fatty acids in plasma cholesterol esters, in a group of
patients with obstructive jaundice and a matched group of controls. Significant abnormalities
were demonstrated, most importantly a fall in essential fatty acids, in the jaundiced group.
Overall the saturation of this fraction, as assessed by double bond index, rose. The essential fatty
acids are important as factors in membrane function and as precursors of eicosanoids. The
abnormalities found in this study provide further evidence of the significance of EFA in patients
with obstructive jaundice
Peer-review in a world with rational scientists: Toward selection of the average
One of the virtues of peer review is that it provides a self-regulating
selection mechanism for scientific work, papers and projects. Peer review as a
selection mechanism is hard to evaluate in terms of its efficiency. Serious
efforts to understand its strengths and weaknesses have not yet lead to clear
answers. In theory peer review works if the involved parties (editors and
referees) conform to a set of requirements, such as love for high quality
science, objectiveness, and absence of biases, nepotism, friend and clique
networks, selfishness, etc. If these requirements are violated, what is the
effect on the selection of high quality work? We study this question with a
simple agent based model. In particular we are interested in the effects of
rational referees, who might not have any incentive to see high quality work
other than their own published or promoted. We find that a small fraction of
incorrect (selfish or rational) referees can drastically reduce the quality of
the published (accepted) scientific standard. We quantify the fraction for
which peer review will no longer select better than pure chance. Decline of
quality of accepted scientific work is shown as a function of the fraction of
rational and unqualified referees. We show how a simple quality-increasing
policy of e.g. a journal can lead to a loss in overall scientific quality, and
how mutual support-networks of authors and referees deteriorate the system.Comment: 5 pages 4 figure
Treatment of premenstrual tension with lithium carbonate â A PILOT STUDY
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66408/1/j.1600-0447.1980.tb00569.x.pd
The effects of n-6 polyunsaturated fatty acids on the expression of nm-23 in human cancer cells.
This study examined the effect of n-6 polyunsaturated fatty acids (PUFAs) on the expression of nm-23, a metastasis-suppressor gene, in two highly invasive human cancer cell lines, HT115 and MDA MB 231. A range of n-6 and n-3 PUFAs were tested. We report that while linoleic acid and arachidonic acid reduced the expression of nm-23-H1, gamma linolenic acid (GLA) and its soluble lithium salt markedly increased the expression of the molecules. The stimulation of the expression of nm-23 by GLA was seen at both protein and mRNA levels. Up-regulation of nm-23 was also associated with a reduction of the in vitro invasiveness of these cells. It is concluded that gamma linolenic acid (GLA) enhances the expression of nm-23. This contributes to the inhibition of the in vitro invasion of tumour cells
Inhibition of hepatocyte growth factor-induced motility and in vitro invasion of human colon cancer cells by gamma-linolenic acid.
In this study we have determined the effects of the n-6 essential fatty acid gamma-linolenic acid (GLA) on the motility and invasive/metastatic nature of the human colon cancer cell lines HT115, HT29 and HRT18. Cell motility was induced by hepatocyte growth factor/scatter factor (HGF/SF) and measured by both colony scattering and dissociation from carrier beads. Invasiveness was measured in vitro by cellular invasion into extracellular matrix. At concentrations up to 100 microM (which had no effect on cell growth over the duration of the experiments) both cell motility and invasion induced by HGF/SF were markedly reduced by GLA and its lithium salt. The attachment of these cells to the extracellular matrix components (Matrigel and fibronectin) was also inhibited. There were also changes in the cell-surface E-cadherin, but not fibronectin receptor at similar concentrations. It is concluded that n-6 essential fatty acids have the ability to inhibit both motility and invasiveness of human colon cancer cells, perhaps by modifying cell-surface adhesion molecules
Nuclear Activity and the Conditions of Star-formation at the Galactic Center
The Galactic Center is the closest galactic nucleus that can be studied with
unprecedented angular resolution and sensitivity. We summarize recent basic
observational results on Sagittarius A* and the conditions for star formation
in the central stellar cluster. We cover results from the radio, infrared, and
X-ray domain and include results from simulation as well. From (sub-)mm and
near-infrared variability and near-infrared polarization data we find that the
SgrA* system (supermassive black hole spin, a potential temporary accretion
disk and/or outflow) is well ordered in its geometrical orientation and in its
emission process that we assume to reflect the accretion process onto the
supermassive black hole (SMBH).Comment: 11 pages, 4 figures, 1 table; published in PoS-SISSA Proceedings of
the: Frontier Research in Astrophysics - II, 23-28 May 2016, Mondello
(Palermo), Ital
How to Create an Innovation Accelerator
Too many policy failures are fundamentally failures of knowledge. This has
become particularly apparent during the recent financial and economic crisis,
which is questioning the validity of mainstream scholarly paradigms. We propose
to pursue a multi-disciplinary approach and to establish new institutional
settings which remove or reduce obstacles impeding efficient knowledge
creation. We provided suggestions on (i) how to modernize and improve the
academic publication system, and (ii) how to support scientific coordination,
communication, and co-creation in large-scale multi-disciplinary projects. Both
constitute important elements of what we envision to be a novel ICT
infrastructure called "Innovation Accelerator" or "Knowledge Accelerator".Comment: 32 pages, Visioneer White Paper, see http://www.visioneer.ethz.c
Experimental Indicators of Accretion Processes in Active Galactic Nuclei
Bright Active Galactic Nuclei are powered by accretion of mass onto the super
massive black holes at the centers of the host galaxies. For fainter objects
star formation may significantly contribute to the luminosity. We summarize
experimental indicators of the accretion processes in Active Galactic Nuclei
(AGN), i.e., observable activity indicators that allow us to conclude on the
nature of accretion. The Galactic Center is the closest galactic nucleus that
can be studied with unprecedented angular resolution and sensitivity.
Therefore, here we also include the presentation of recent observational
results on Sagittarius A* and the conditions for star formation in the central
stellar cluster. We cover results across the electromagnetic spectrum and find
that the Sagittarius A* (SgrA*) system is well ordered with respect to its
geometrical orientation and its emission processes of which we assume to
reflect the accretion process onto the super massive black hole.Comment: 16 pages, 4 figures, conference proceeding: Accretion Processes in
Cosmic Sources - APCS2016 - 5-10 September 2016, Saint Petersburg, Russi
SINFONI in the Galactic Center: young stars and IR flares in the central light month
We report 75 milli-arcsec resolution, near-IR imaging spectroscopy within the
central 30 light days of the Galactic Center [...]. To a limiting magnitude of
K~16, 9 of 10 stars in the central 0.4 arcsec, and 13 of 17 stars out to 0.7
arcsec from the central black hole have spectral properties of B0-B9, main
sequence stars. [...] all brighter early type stars have normal rotation
velocities, similar to solar neighborhood stars. We [...] derive improved 3d
stellar orbits for six of these S-stars in the central 0.5 arcsec. Their
orientations in space appear random. Their orbital planes are not co-aligned
with those of the two disks of massive young stars 1-10 arcsec from SgrA*. We
can thus exclude [...] that the S-stars as a group inhabit the inner regions of
these disks. They also cannot have been located/formed in these disks [...].
[...] we conclude that the S-stars were most likely brought into the central
light month by strong individual scattering events. The updated estimate of
distance to the Galactic center from the S2 orbit fit is Ro = 7.62 +/- 0.32
kpc, resulting in a central mass value of 3.61 +/- 0.32 x 10^6 Msun. We
happened to catch two smaller flaring events from SgrA* [...]. The 1.7-2.45 mum
spectral energy distributions of these flares are fit by a featureless, red
power law [...]. The observed spectral slope is in good agreement with
synchrotron models in which the infrared emission comes from [...] radiative
inefficient accretion flow in the central R~10 Rs region.Comment: 50 pages, 10 figures, 2 tables, submitted to ApJ, February 6th, 2005,
abstract abridge
- âŠ