237 research outputs found
Radio monitoring of the periodically variable IR source LRLL 54361: No direct correlation between the radio and IR emissions
J. Forbrich, âRadio monitoring of the periodically variable IR source LRLL 54361: No direct correlation between the radio and IR emissionsâ, The Astrophysical Journal, Vol. 814(1), November 2015. © 2015. The American Astronomical Society.LRLL 54361 is an infrared source located in the star forming region IC 348 SW. Remarkably, its infrared luminosity increases by a factor of 10 during roughly one week every 25.34 days. To understand the origin of these remarkable periodic variations, we obtained sensitive 3.3 cm JVLA radio continuum observations of LRLL 54361 and its surroundings in six different epochs: three of them during the IR-on state and three during the IR-off state. The radio source associated with LRLL 54361 remained steady and did not show a correlation with the IR variations. We suggest that the IR is tracing the results of fast (with a timescale of days) pulsed accretion from an unseen binary companion, while the radio traces an ionized outflow with an extent of 100 AU that smooths out the variability over a period of order a year. The average flux density measured in these 2014 observations, 275 Jy, is about a factor of two less than that measured about 1.5 years before, 11 Jy, suggesting that variability in the radio is present, but over larger timescales than in the IR. We discuss other sources in the field, in particular two infrared/X-ray stars that show rapidly varying gyrosynchrotron emission.Peer reviewe
Genotoxic Effects in Swimmers Exposed to Disinfection By-products in Indoor Swimming Pools
37 pĂĄginas, 1 figura, 4 tablas.-- PDF con material suplementario.[BACKGROUND]: Exposure to disinfection by-products (DBPs) in drinking water has
been associated with cancer risk. A recent study found an increased bladder cancer risk
among subjects attending swimming pools relative to those not attending.[OBJECTIVES]: To evaluate whether swimming in pools is associated with biomarkers
of genotoxicity.[METHODS]: We collected blood, urine, and exhaled air samples from 49 non-smoking
adult volunteers before and after they swam for 40 min in an indoor chlorinated pool.
We estimated associations between the concentrations of four trihalomethanes in
exhaled breath and changes in the following biomarkers: micronuclei and DNA damage
(comet assay) in peripheral blood lymphocytes before and 1 h after swimming, urine
mutagenicity (Ames assay) before and 2 h after swimming, and micronuclei in
exfoliated urothelial cells before and 2 weeks after swimming. We also estimated
associations and interactions with polymorphisms in genes related to DNA repair or
DBP metabolism.[RESULTS]: After swimming, the total concentration of the four trihalomethanes in
exhaled breath was seven times higher than before swimming. The change in the
frequency of micronucleated lymphocytes after swimming increased in association with
exhaled concentrations of the brominated trihalomethanes (p = 0.03 for CHCl2Br, p =
0.05 for CHClBr2, p = 0.01 for CHBr3) but not chloroform. Swimming was not
associated with DNA damage detectable by the comet assay. Urine mutagenicity
increased significantly after swimming in association with the concentration of exhaled
CHBr3 (p = 0.004). No significant associations with changes in micronucleated
urothelial cells were observed.[CONCLUSIONS]: Our findings support potential genotoxic effects of exposure to
DBPs from swimming pools. The positive health effects gained by swimming could be
increased by reducing the potential health risks of pool water.Research
supported by Plan Nacional Grant SAF2005-07643-C03-01/02/03, Spain and FIS
CP06/00341, Spain. CM Villanueva supported by the ISCIII (CP06/00341), Spain, L
Font-Ribera by a predoctoral fellowship (FI06/00651), Spain, and D Liviac by a
postgraduate fellowship UAB (PIF409-009), Barcelona.Peer reviewe
Direct observational evidence of the multi-scale, dynamical mass accretion toward a high-mass star forming hub-filament system
There is growing evidence that high-mass star formation and hub-filament
systems (HFS) are intricately linked. The gas kinematics along the filaments
and the forming high-mass star(s) in the central hub are in excellent agreement
with the new generation of global hierarchical high-mass star formation models.
In this paper, we present an observational investigation of a typical HFS
cloud, G310.142+0.758 (G310 hereafter) which reveals unambiguous evidence of
mass inflow from the cloud scale via the filaments onto the forming
protostar(s) at the hub conforming with the model predictions. Continuum and
molecular line data from the ATOMS and MALT90 surveys are used that cover
different spatial scales. Three filaments (with total mass ) are identified converging toward the central hub region where
several signposts of high-mass star formation have been observed. The hub
region contains a massive clump () harbouring a central
massive core. Additionally, five outflow lobes are associated with the central
massive core implying a forming cluster. The observed large-scale, smooth and
coherent velocity gradients from the cloud down to the core scale, and the
signatures of infall motion seen in the central massive clump and core, clearly
unveil a nearly-continuous, multi-scale mass accretion/transfer process at a
similar mass infall rate of over all scales,
feeding the central forming high-mass protostar(s) in the G310 HFS cloud.Comment: Accepted to publish in ApJ. 10 pages with 6 figures and 2 table
The Use of Phage-Displayed Peptide Libraries to Develop Tumor-Targeting Drugs
Monoclonal antibodies have been successfully utilized as cancer-targeting therapeutics and diagnostics, but the efficacies of these treatments are limited in part by the size of the molecules and non-specific uptake by the reticuloendothelial system. Peptides are much smaller molecules that can specifically target cancer cells and as such may alleviate complications with antibody therapy. Although many endogenous and exogenous peptides have been developed into clinical therapeutics, only a subset of these consists of cancer-targeting peptides. Combinatorial biological libraries such as bacteriophage-displayed peptide libraries are a resource of potential ligands for various cancer-related molecular targets. Target-binding peptides can be affinity selected from complex mixtures of billions of displayed peptides on phage and further enriched through the biopanning process. Various cancer-specific ligands have been isolated by in vitro, in vivo, and ex vivo screening methods. As several peptides derived from phage-displayed peptide library screenings have been developed into therapeutics in current clinical trials, which validates peptide-targeting potential, the use of phage display to identify cancer-targeting therapeutics should be further exploited
Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging
The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular âblueprintâ; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as âcontrast agentsâ if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging
Reference Ranges for the Clinical Laboratory Derived from a Rural Population in Kericho, Kenya
The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrolment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9â¶1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/”l. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7â11.1) and neutrophil counts (1850 cells/”l; range 914â4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment
The ALMA Survey of Star Formation and Evolution in Massive Protoclusters with Blue Profiles (ASSEMBLE): Core Growth, Cluster Contraction, and Primordial Mass Segregation
The ALMA Survey of Star Formation and Evolution in Massive Protoclusters with
Blue Profiles (ASSEMBLE) aims to investigate the process of mass assembly and
its connection to high-mass star formation theories in protoclusters in a
dynamic view. We observed 11 massive (Mclump>1000 Msun), luminous (Lbol>10,000
Lsun), and blue-profile (infall signature) clumps by ALMA with resolution of
2200-5500 au at 350 GHz (870 um) in continuum and line emission. 248 dense
cores were identified, including 106 cores showing protostellar signatures and
142 prestellar core candidates. Compared to early-stage infrared dark clouds
(IRDCs) by ASHES, the core mass and surface density within the ASSEMBLE clumps
exhibited significant increment, suggesting concurrent core accretion during
the evolution of the clumps. The maximum mass of prestellar cores was found to
be 2 times larger than that in IRDCs, indicating evolved protoclusters have the
potential to harbor massive prestellar cores. The mass relation between clumps
and their most massive core (MMCs) is observed in ASSEMBLE but not in IRDCs,
which is suggested to be regulated by multiscale mass accretion. The mass
correlation between the core clusters and their MMCs has a steeper slope
compared to that observed in stellar clusters, which can be due to
fragmentation of the MMC and stellar multiplicity. We observe a decrease in
core separation and an increase in central concentration as protoclusters
evolve. We confirm primordial mass segregation in the ASSEMBLE protoclusters,
possibly resulting from gravitational concentration and/or gas accretion.Comment: 37 pages, 13 figures, 5 tables; accepted for publication in ApJ
Isotemporal substitution of inactive time with physical activity and time in bed: cross-sectional associations with cardiometabolic health in the PREDIMEDPlus study
Background: This study explored the association between inactive time and measures of adiposity, clinical parameters, obesity, type 2 diabetes and metabolic syndrome components. It further examined the impact of reallocating inactive time to time in bed, light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) on cardio-metabolic risk factors, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults.
Methods: This is a cross-sectional analysis of baseline data from 2189 Caucasian men and women (age 55-75 years, BMI 27-40 Kg/m2) from the PREDIMED-Plus study (http://www.predimedplus.com/). All participants had â„3 components of the metabolic syndrome. Inactive time, physical activity and time in bed were objectively determined using triaxial accelerometers GENEActiv during 7 days (ActivInsights Ltd., Kimbolton, United Kingdom). Multiple adjusted linear and logistic regression models were used. Isotemporal substitution regression modelling was performed to assess the relationship of replacing the amount of time spent in one activity for another, on each outcome, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults.
Results: Inactive time was associated with indicators of obesity and the metabolic syndrome. Reallocating 30 min per day of inactive time to 30 min per day of time in bed was associated with lower BMI, waist circumference and glycated hemoglobin (HbA1c) (all p-values < 0.05). Reallocating 30 min per day of inactive time with 30 min per day of LPA or MVPA was associated with lower BMI, waist circumference, total fat, visceral adipose tissue, HbA1c, glucose, triglycerides, and higher body muscle mass and HDL cholesterol (all p-values < 0.05).
Conclusions: Inactive time was associated with a poor cardio-metabolic profile. Isotemporal substitution of inactive time with MVPA and LPA or time in bed could have beneficial impact on cardio-metabolic health
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