720 research outputs found
CHIRON - A Fiber Fed Spectrometer for Precise Radial Velocities
The CHIRON optical high-resolution echelle spectrometer was commissioned at
the 1.5m telescope at CTIO in 2011. The instrument was designed for high
throughput and stability, with the goal of monitoring radial velocities of
bright stars with high precision and high cadence for the discovery of low-mass
exoplanets. Spectral resolution of R=79,000 is attained when using a slicer
with a total (including telescope and detector) efficiency of 6% or higher,
while a resolution of R=136,000 is available for bright stars. A fixed spectral
range of 415 to 880 nm is covered. The echelle grating is housed in a vacuum
enclosure and the instrument temperature is stabilized to +-0.2deg. Stable
illumination is provided by an octagonal multimode fiber with excellent
light-scrambling properties. An iodine cell is used for wavelength calibration.
We describe the main optics, fiber feed, detector, exposure-meter, and other
aspects of the instrument, as well as the observing procedure and data
reduction.Comment: 15 pages, 10 figures. Accepted by PAS
Predictive gaze cues affect face evaluations: The effect of facial emotion
When we see someone change their direction of gaze, we spontaneously follow their eyes because we expect people to look at interesting objects. Bayliss and Tipper (2006) examined the consequences of observing this expectancy being either confirmed or violated by faces producing reliable or unreliable gaze cues. Participants viewed different faces that would consistently look at the target, or consistently look away from the target: The faces that consistently looked towards targets were subsequently chosen as being more trustworthy than the faces that consistently looked away from targets. The current work demonstrates that these gaze contingency effects are only detected when faces create a positive social context by smiling, but not in the negative context when all the faces held angry or neutral expressions. These data suggest that implicit processing of the reward contingencies associated with gaze cues relies on a positive emotional expression to maintain expectations of a favourable outcome of joint attention episodes
Description of normal pulmonary radiographic findings in 55 apparently healthy juvenile Kemp's ridley sea turtles (Lepidochelys kempii)
A total of 55 digital radiographic studies from 53 individual juvenile Kemp's ridley sea turtles (Lepidochelys kempii) were retrospectively used to determine the normal radiographic anatomy of the lower respiratory tract in sea turtles that had been stranded due to hook-and-line injury and were otherwise clinically healthy. There were three or four projections available for each study: dorsoventral (DV), rostrocaudal (RoCd), and left and/or right lateral. The DV and RoCd were most conducive for assessing global lung volume and symmetry of lung volume. The DV and lateral views were most helpful for evaluating the main bronchus and its branching channels and for assessing lung margination. The RoCd view was most useful for assessing the symmetry of the lung opacity. The lateral views were most helpful for assessing the ventral margin of each lung lobe. On the lateral view, the main bronchus lay ventrally and coursed horizontally through the lung from cranial to caudal. On the DV view, the bronchus lay medially and was observed to be curvilinear coursing caudomedially. On the RoCd view, the main bronchus was located ventromedially. The RoCd view demonstrated the channels and niches end-on resulting in a reticulated or honeycomb appearance. The channels were seen as uniform striations coursing perpendicular to the main bronchus on the lateral views (vertical striations coursing dorsal to ventral) and DV views (horizontal striations coursing medially to laterally)
Genetic and Non-genetic Predictors of LINE-1 Methylation in Leukocyte DNA
Background: Altered DNA methylation has been associated with various diseases.
Objective: We evaluated the association between levels of methylation in leukocyte DNA at long interspersed nuclear element 1 (LINE-1) and genetic and non-genetic characteristics of 892 control participants from the Spanish Bladder Cancer/EPICURO study.
Methods: We determined LINE-1 methylation levels by pyrosequencing. Individual data included demographics, smoking status, nutrient intake, toenail concentrations of 12 trace elements, xenobiotic metabolism gene variants, and 515 polymorphisms among 24 genes in the one-carbon metabolism pathway. To assess the association between LINE-1 methylation levels (percentage of methylated cytosines) and potential determinants, we estimated beta coefficients (βs) by robust linear regression.
Results: Women had lower levels of LINE-1 methylation than men (β = –0.7, p = 0.02). Persons who smoked blond tobacco showed lower methylation than nonsmokers (β = –0.7, p = 0.03). Arsenic toenail concentration was inversely associated with LINE-1 methylation (β = –3.6, p = 0.003). By contrast, iron (β = 0.002, p = 0.009) and nickel (β = 0.02, p = 0.004) were positively associated with LINE-1 methylation. Single nucleotide polymorphisms (SNPs) in DNMT3A (rs7581217-per allele, β = 0.3, p = 0.002), TCN2 (rs9606756-GG, β = 1.9, p = 0.008; rs4820887-AA, β = 4.0, p = 4.8 × 10–7; rs9621049-TT, β = 4.2, p = 4.7 × 10–9), AS3MT (rs7085104-GG, β = 0.7, p = 0.001), SLC19A1 (rs914238, TC vs. TT: β = 0.5 and CC vs. TT: β = –0.3, global p = 0.0007) and MTHFS (rs1380642, CT vs. CC: β = 0.3 and TT vs. CC; β = –0.8, global p = 0.05) were associated with LINE-1 methylation.
Conclusions: We identified several characteristics, environmental factors, and common genetic variants that predicted DNA methylation among study participants
Global functional analysis of nucleophosmin in Taxol response, cancer, chromatin regulation, and ribosomal DNA transcription
Analysis of lung cancer response to chemotherapeutic agents showed the accumulation of a Taxol-induced protein that reacted with an anti-phospho-MEK1/2 antibody. Mass spectroscopy identified the protein as nucleophosmin/B23 (NPM), a multifunctional protein with diverse roles: ribosome biosynthesis, p53 regulation, nuclear-cytoplasmic shuttling, and centrosome duplication. Our work demonstrates that following cellular exposure to mitosis-arresting agents NPM is phosphorylated and its chromatographic property is altered, suggesting changes in function during mitosis. To determine the functional relevance of NPM, its expression in tumor cells was reduced by siRNA. Cells with reduced NPM were treated with Taxol followed by microarray profiling accompanied by gene/protein pathway analyses. These studies demonstrate several expected and unexpected consequences of NPM depletion. The predominant downstream effectors of NPM are genes involved in cell proliferation, cancer, and the cell cycle. In congruence with its role in cancer, NPM is over-expressed in primary malignant lung cancer tissues. We also demonstrate a role for NPM in the expression of genes encoding SET (TAF1β) and the histone methylase SET8. Additionally, we show that NPM is required for a previously unobserved G2/M upregulation of TAF1A, which encodes the rDNA transcription factor TAFI48. These results demonstrate multi-faceted functions of NPM that can affect cancer cells
Genetic and Non-genetic Predictors of LINE-1 Methylation in Leukocyte DNA.
Background: Altered DNA methylation has been associated with various diseases. Objective: We evaluated the association between levels of methylation in leukocyte DNA at long interspersed nuclear element 1 (LINE-1) and genetic and non-genetic characteristics of 892 control participants from the Spanish Bladder Cancer/EPICURO study. Methods: We determined LINE-1 methylation levels by pyrosequencing. Individual data included demographics, smoking status, nutrient intake, toenail concentrations of 12 trace elements, xenobiotic metabolism gene variants, and 515 polymorphisms among 24 genes in the one-carbon metabolism pathway. To assess the association between LINE-1 methylation levels (percentage of methylated cytosines) and potential determinants, we estimated beta coefficients (βs) by robust linear regression. Results: Women had lower levels of LINE-1 methylation than men (β = –0.7, p = 0.02). Persons who smoked blond tobacco showed lower methylation than nonsmokers (β = –0.7, p = 0.03). Arsenic toenail concentration was inversely associated with LINE-1 methylation (β = –3.6, p = 0.003). By contrast, iron (β = 0.002, p = 0.009) and nickel (β = 0.02, p = 0.004) were positively associated with LINE-1 methylation. Single nucleotide polymorphisms (SNPs) in DNMT3A (rs7581217-per allele, β = 0.3, p = 0.002), TCN2 (rs9606756-GG, β = 1.9, p = 0.008; rs4820887-AA, β = 4.0, p = 4.8 Ă— 10–7; rs9621049-TT, β = 4.2, p = 4.7 Ă— 10–9), AS3MT (rs7085104-GG, β = 0.7, p = 0.001), SLC19A1 (rs914238, TC vs. TT: β = 0.5 and CC vs. TT: β = –0.3, global p = 0.0007) and MTHFS (rs1380642, CT vs. CC: β = 0.3 and TT vs. CC; β = –0.8, global p = 0.05) were associated with LINE-1 methylation. Conclusions: We identified several characteristics, environmental factors, and common genetic variants that predicted DNA methylation among study participants.This work was partially supported by the Association for International Cancer Research (AICR; grant 09-0780, and a doctoral scholarship awarded to S.M.T.); Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, MINECO, Spain (grants 00/0745, PI051436, PI061614, PI09-02102, and G03/174); Red Temática de InvestigaciĂłn Cooperativa en Cáncer (grant RD06/0020-RTICC); the U.S. National Institutes of Health (grant RO1-CA089715); a postdoctoral fellowship awarded to A.F.S.A. from the FundaciĂłn CientĂfica de la AECC; FundaciĂł MaratĂł TV3; and The Johns Hopkins University Vredenburg Scholarship awarded to A.L.C
Effective suckling in relation to naked maternal-infant body contact in the first hour of life: an observation study
Background
Best practice guidelines to promote breastfeeding suggest that (i) mothers hold their babies in naked body contact immediately after birth, (ii) babies remain undisturbed for at least one hour and (iii) breastfeeding assistance be offered during this period. Few studies have closely observed the implementation of these guidelines in practice. We sought to evaluate these practices on suckling achievement within the first hour after birth.
Methods
Observations of seventy-eight mother-baby dyads recorded newborn feeding behaviours, the help received by mothers and birthing room practices each minute, for sixty minutes.
Results
Duration of naked body contact between mothers and their newborn babies varied widely from 1 to 60 minutes, as did commencement of suckling (range = 10 to 60 minutes). Naked maternal-infant body contact immediately after birth, uninterrupted for at least thirty minutes did not predict effective suckling within the first hour of birth. Newborns were four times more likely to sustain deep rhythmical suckling when their chin made contact with their mother’s breast as they approached the nipple (OR 3.8; CI 1.03 - 14) and if their mothers had given birth previously (OR 6.7; CI 1.35 - 33). Infants who had any naso-oropharyngeal suctioning administered at birth were six times less likely to suckle effectively (OR .176; CI .04 - .9).
Conclusion
Effective suckling within the first hour of life was associated with a collection of practices including infants positioned so their chin can instinctively nudge the underside of their mother’s breast as they approach to grasp the nipple and attach to suckle. The best type of assistance provided in the birthing room that enables newborns to sustain an effective latch was paying attention to newborn feeding behaviours and not administering naso-oropharyngeal suction routinely
The NLRP3 Inflammasome Mediates In Vivo Innate Immunity to Influenza A Virus through Recognition of Viral RNA
NLR genes mediate host immunity to various pathogenic stimuli. However, in vivo evidence for NLR involvement in viral sensing has not been widely investigated and remains controversial. As an ultimate test of the physiologic role of NLRP3 during RNA viral infection, this work explores the in vivo role of NLRP3 inflammasome components during influenza virus infection. Mice lacking Nlrp3, ASC, or Caspase-1, but not Nlrc4, exhibit dramatically increased mortality but reduced immune response following influenza virus exposure. Utilizing analogs of dsRNA (poly(I:C)) and ssRNA (ssRNA40), we demonstrate that NLRP3-mediated response can be activated by RNA species. Mechanistically, NLRP3 inflammasome activation by influenza virus is dependent upon lysosomal maturation and reactive oxygen species. Inhibition of ROS induction eliminated IL-1β production in animals during influenza infection. Together, these data place the NLRP3 inflammasome as an essential component in host defense against influenza infection through the sensing of viral RNA
Spitzer IRAC and MIPS Imaging of Clusters and Outflows in 9 High-mass Star Forming Regions
We present Spitzer Space Telescope IRAC and MIPS observations toward a sample
of nine high-mass star forming regions at a distance of around 2 kpc. Based on
IRAC and MIPS 24 m photometric results and 2MASS JHKs data, we carry out a
census of young stellar objects (YSOs) in a 5' by 5' field toward each region.
Toward seven out of the nine regions, we detect parsec sized clusters with
around 20 YSOs surrounded by a more extended and sparse distribution of young
stars and protostars. For the other two regions, IRAS 20126+4104 and IRAS
22172+5549, the former has the lowest number of YSOs in the sample and shows no
obvious cluster, and the latter appears to be part of a larger, potentially
more evolved cluster. The deep IRAC imaging reveals at least twelve outflows in
eight out of the nine regions, with nine outflows prominent in the 4.5 m
band most probably attributed to shocked H emission, two outflows dominated
by scattered light in the 3.6 and 4.5 m bands, and one outflow standing
out from its hydrocarbon emission in the 8.0 m band. In comparison with
previous ground-based observations, our IRAC observations reveal new outflow
structures in five regions. The dramatically different morphologies of detected
outflows can be tentatively interpreted in terms of possible evolution of
massive outflows. The driving sources of these outflows are deeply embedded in
dense dusty cores revealed by previous millimeter interferometric observations.
We detect infrared counterparts of these dusty cores in the IRAC or MIPS 24
m bands. Reflection nebulae dominated by the emission from UV heated
hydrocarbons in the 8 m band can be found in most regions and they may
imply the presence of young B stars.Comment: 76 pages, 25 figures and 5 tables, ApJ in press, a full resolution
version available at http://www.cfa.harvard.edu/~kqiu/spitzer.pd
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