4,435 research outputs found
Erratum: Is it possible to infer the equation of state of a mixture of hard discs from that of the one-component system?
The numerical values in the sixth and seventh columns of table 1 of the paper
Molec. Phys., 1999, 96, 1185-1188 are not correct. Consequently, some of the
comments made in the paper are wrong. The corrected version of table 1 is
reprinted here and the results are briefly discussed.Comment: 2 pages; Erratum to Molec. Phys., 1999, 96, 1185-1188; to be
published in Molec. Phy
Dydrogesterone and norethisterone regulate expression of lipoprotein lipase and hormones-sensitive lipase in human subcutaneous abdominal adipocytes
Aim: In premenopausal women, hyper-androgenicity is associated with central obesity and an increased cardiovascular risk. We investigated the effects of dydrogesterone (DYD)(a non-androgenic progestogen) and norethisterone (NET)(an androgenic progestogen) on lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and glycerol release in adipocytes isolated from subcutaneous abdominal adipose tissue. Methods: Adipose tissue was obtained from 12 non-diabetic women, mean age 51 years (range 37-78) and mean BMI 25.4kg/m2 (range 20.3-26.4). Adipocytes were treated with increasing doses of DYD and NET for 48 hours prior to protein extraction. Effects on lipogenesis and lipolysis were assessed using western blotting to determine the expression of key enzymes, LPL (56kDa) and HSL (84kDa) respectively. Measurement of glycerol release into the medium provided an assessment of lipolytic activity. Results: Expression of LPL was increased by DYD and NET (mean protein expression relative to control ± SEM); with greatest effect at 10-8M for DYD: 2.32±0.51(p0.05). Conclusions: DYD and NET significantly increased LPL expression relative to control whilst significantly reducing HSL expression. At the concentrations studied, similar effects were observed with the androgenic NET and the non-androgenic DYD despite differing effects on the lipid profile when taken
in combination with estrogen. Further work in this area may improve knowledge about the effects of different progestogens on body fat distribution and enable progestogen use to be tailored to the individual to achieve maximal benefits
Pythagorean Approximations for LEGO: Merging Educational Robot Construction with Programming and Data Analysis
Abstract. This paper can be used in two ways. It can provide reference information for incorporating diagonal elements (for bracing or gear meshing) in educational robots built from standard LEGO kits. Alternatively, it can be used as the basis for an assignment for high school or college students to recreate this information; in the process, students will exercise skills in both computer programming and data analysis. Using the paper in the second way can be an excellent integrative experience to add to an existing course; for example, the Exploring Computer Science high school curriculum concludes with the units “Introduction to Programming”, “Computing and Data Analysis”, and “Robotics”
HIV infection significantly reduces lipoprotein lipase which remains low after 6 months of antiretroviral therapy
Purpose of the study
Fractional clearance rate of apolipoprotein B100-containing
lipoproteins is reduced in HIV infection before and
after antiretroviral (ARV) treatment [1]. We compared
lipoprotein lipase (LPL) activity and gene expression in
HIV-positive subjects before and 6 months after ARV with
HIV-negative controls.
Methods
Fasting blood post heparin total and hepatic lipase activity,adiponectin, leptin, insulin, glucose, and lipid measurementswere made in 32 HIV-infected and 15 HIVnegative
controls. LPL was estimated by subtractinghepatic lipase from total lipase. Adiponectin, LPL andhormone sensitive lipase (HSL) gene expression weremeasured from iliac crest subcutaneous fat biopsies.Patients were tested before, and 6 months after randomisation to AZT/3TC (n = 15) or TDF/FTC (n = 17) with EFV.Between-group comparison was by Mann-Whitney andpaired samples by the Wilcoxon signed rank tests.
Summary of results
There were no differences in gender, ethnicity, baseline
BMI, regional fat distribution (whole body DEXA) and
visceral (VAT) and subcutaneous fat (SAT) measured by
abdominal CT scans between controls and patients. Trunk
fat/BMI ratio, VAT and VAT:SAT ratio significantly
increased after 6-month ARV therapy (p = 0.01). There
were no differences between groups in serum NEFA,HOMA and leptin levels. Selected other results are shown
in Table 1.
Conclusion
Post heparin lipoprotein lipase activity is reduced in HIV
and does not return to control levels after 6 months of
ARV therapy. AZT-containing regimens are associated
with a greater increase in LPL, LPL gene expression and
plasma adiponectin than TDF
The Effect of Electronic Cigarette User Modifications and E-liquid Adulteration on the Particle Size Profile of an Aerosolized Product
Electronic cigarettes (e-cigarettes) are an alternate nicotine delivery system that generate a condensation aerosol to be inhaled by the user. The size of the droplets formed in the aerosol can vary and contributes to drug deposition and ultimate bioavailability in the lung. The growing popularity of e-cigarette products has caused an increase in internet sources promoting the use of drugs other than nicotine (DOTNs) in e-cigarettes. The purpose of this study was to determine the effect of various e-cigarette and e-liquid modifications, such as coil resistance, battery voltage, and glycol and drug formulation, on the aerosol particle size. E-liquids containing 12 mg/mL nicotine prepared in glycol compositions of 100% propylene glycol (PG), 100% vegetable glycerin (VG), or 50:50 PG:VG were aerosolized at three voltages and three coil resistances. Methamphetamine and methadone e-liquids were prepared at 60 mg/mL in 50:50 PG:VG and all e-liquids were aerosolized onto a 10 stage Micro-Orifice Uniform Deposit Impactor. Glycol deposition correlated with drug deposition, and the majority of particles centered between 0.172–0.5 μm in diameter, representing pulmonary deposition. The 100% PG e-liquid produced the largest aerosol particles and the 100% VG and 50:50 PG:VG e-liquids produced ultra-fine particles \u3c0.3 μm. The presence of ultrafine particles indicates that drugs can be aerosolized and reach the pulmonary alveolar regions, highlighting a potential for abuse and risk of overdose with DOTNs aerosolized in an e-cigarette system
The GEEC2 spectroscopic survey of Galaxy Groups at
We present the data release of the Gemini-South GMOS spectroscopy in the
fields of 11 galaxy groups at , within the COSMOS field. This forms
the basis of the Galaxy Environment Evolution Collaboration 2 (GEEC2) project
to study galaxy evolution in haloes with across cosmic
time. The final sample includes spectroscopically--confirmed members with
per cent complete for galaxies within the virial
radius, and with stellar mass . Including
galaxies with photometric redshifts we have an effective sample size of galaxies within the virial radii of these groups. We present group
velocity dispersions, dynamical and stellar masses. Combining with the GCLASS
sample of more massive clusters at the same redshift we find the total stellar
mass is strongly correlated with the dynamical mass, with
. This stellar
fraction of per cent is lower than predicted by some halo occupation
distribution models, though the weak dependence on halo mass is in good
agreement. Most groups have an easily identifiable most massive galaxy (MMG)
near the centre of the galaxy distribution, and we present the spectroscopic
properties and surface brightness fits to these galaxies. The total stellar
mass distribution in the groups, excluding the MMG, compares well with an NFW
profile with concentration , for galaxies beyond . This is
more concentrated than the number density distribution, demonstrating that
there is some mass segregation.Comment: Accepted for publication in MNRAS. The appendix is omitted due to
large figures. The full version will be available from the MNRAS website and
from http://quixote.uwaterloo.ca/~mbalogh/papers/GEEC2_data.pdf. Long data
tables are available from MNRAS or by contacting the first autho
The Stellar Content of Obscured Galactic Giant H II Regions IV.: NGC3576
We present deep, high angular resolution near-infrared images of the obscured
Galactic Giant H II region NGC3576. Our images reach objects to ~3M_sun. We
collected high signal-to-noise K-band spectra of eight of the brightest
objects, some of which are affected by excess emission and some which follow a
normal interstellar reddening law. None of them displayed photospheric features
typical of massive OB type stars. This indicates that they are still enshrouded
in their natal cocoons. The K-band brightest source (NGC3576 #48) shows CO 2.3
micron bandhead emission, and three others have the same CO feature in
absorption. Three sources display spatially unresolved H_2 emission, suggesting
dense shocked regions close to the stars. We conclude that the remarkable
object NGC3576 #48 is an early-B/late-O star surrounded by a thick
circumstellar disk. A number of other relatively bright cluster members also
display excess emission in the K-band, indicative of reprocessing disks around
massive stars (YSOs). Such emission appears common in other Galactic Giant H II
regions we have surveyed. The IMF slope of the cluster, Gamma = -1.51, is
consistent with Salpeter's distribution and similar to what has been observed
in the Magellanic Cloud clusters and in the periphery of our Galaxy.Comment: 14 pages, 11 figures, accepted for publication in A
The XXL Survey VIII: MUSE characterisation of intracluster light in a z0.53 cluster of galaxies
Within a cluster, gravitational effects can lead to the removal of stars from
their parent galaxies. Gas hydrodynamical effects can additionally strip gas
and dust from galaxies. The properties of the ICL can therefore help constrain
the physical processes at work in clusters by serving as a fossil record of the
interaction history. The present study is designed to characterise this ICL in
a ~10^14 M_odot and z~0.53 cluster of galaxies from imaging and spectroscopic
points of view. By applying a wavelet-based method to CFHT Megacam and WIRCAM
images, we detect significant quantities of diffuse light. These sources were
then spectroscopically characterised with MUSE. MUSE data were also used to
compute redshifts of 24 cluster galaxies and search for cluster substructures.
An atypically large amount of ICL has been detected in this cluster. Part of
the detected diffuse light has a very weak optical stellar component and
apparently consists mainly of gas emission, while other diffuse light sources
are clearly dominated by old stars. Furthermore, emission lines were detected
in several places of diffuse light. Our spectral analysis shows that this
emission likely originates from low-excitation parameter gas. The stellar
contribution to the ICL is about 2.3x10^9 yrs old even though the ICL is not
currently forming a large number of stars. On the other hand, the contribution
of the gas emission to the ICL in the optical is much greater than the stellar
contribution in some regions, but the gas density is likely too low to form
stars. These observations favour ram pressure stripping, turbulent viscous
stripping, or supernovae winds as the origin of the large amount of
intracluster light. Since the cluster appears not to be in a major merging
phase, we conclude that ram pressure stripping is the most plausible process
that generates the observed ICL sources.Comment: Accepted in A&A, english enhanced, figure location different than in
the A&A version due to different style files, shortened abstrac
The XXL Survey X: K-band luminosity - weak-lensing mass relation for groups and clusters of galaxies
We present the K-band luminosity-halo mass relation, ,
for a subsample of 20 of the 100 brightest clusters in the XXL Survey observed
with WIRCam at the Canada-France-Hawaii Telescope (CFHT). For the first time,
we have measured this relation via weak-lensing analysis down to . This allows us to investigate whether the slope
of the relation is different for groups and clusters, as seen in other
works. The clusters in our sample span a wide range in mass, , at . The K-band luminosity
scales as with and an
intrinsic scatter of . Combining our
sample with some clusters in the Local Cluster Substructure Survey (LoCuSS)
present in the literature, we obtain a slope of and an
intrinsic scatter of . The flattening in the seen
in previous works is not seen here and might be a result of a bias in the mass
measurement due to assumptions on the dynamical state of the systems. We also
study the richness-mass relation and find that group-sized halos have more
galaxies per unit halo mass than massive clusters. However, the brightest
cluster galaxy (BCG) in low-mass systems contributes a greater fraction to the
total cluster light than BCGs do in massive clusters; the luminosity gap
between the two brightest galaxies is more prominent for group-sized halos.
This result is a natural outcome of the hierarchical growth of structures,
where massive galaxies form and gain mass within low-mass groups and are
ultimately accreted into more massive clusters to become either part of the BCG
or one of the brighter galaxies. [Abridged]Comment: A&A, in pres
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