3,432 research outputs found
Thyroxine differentially modulates the peripheral clock: lessons from the human hair follicle
The human hair follicle (HF) exhibits peripheral clock activity, with knock-down of clock genes (BMAL1 and PER1) prolonging active hair growth (anagen) and increasing pigmentation. Similarly, thyroid hormones prolong anagen and stimulate pigmentation in cultured human HFs. In addition they are recognized as key regulators of the central clock that controls circadian rhythmicity. Therefore, we asked whether thyroxine (T4) also influences peripheral clock activity in the human HF. Over 24 hours we found a significant reduction in protein levels of BMAL1 and PER1, with their transcript levels also decreasing significantly. Furthermore, while all clock genes maintained their rhythmicity in both the control and T4 treated HFs, there was a significant reduction in the amplitude of BMAL1 and PER1 in T4 (100 nM) treated HFs. Accompanying this, cell-cycle progression marker Cyclin D1 was also assessed appearing to show an induced circadian rhythmicity by T4 however, this was not significant. Contrary to short term cultures, after 6 days, transcript and/or protein levels of all core clock genes (BMAL1, PER1, clock, CRY1, CRY2) were up-regulated in T4 treated HFs. BMAL1 and PER1 mRNA was also up-regulated in the HF bulge, the location of HF epithelial stem cells. Together this provides the first direct evidence that T4 modulates the expression of the peripheral molecular clock. Thus, patients with thyroid dysfunction may also show a disordered peripheral clock, which raises the possibility that short term, pulsatile treatment with T4 might permit one to modulate circadian activity in peripheral tissues as a target to treat clock-related disease
No detectable radio emission from the magnetar-like pulsar in Kes 75
The rotation-powered pulsar PSR J1846-0258 in the supernova remnant Kes 75
was recently shown to have exhibited magnetar-like X-ray bursts in mid-2006.
Radio emission has not yet been observed from this source, but other
magnetar-like sources have exhibited transient radio emission following X-ray
bursts. We report on a deep 1.9 GHz radio observation of PSR J1846-0258 with
the 100-m Green Bank Telescope in late 2007 designed to search for radio
pulsations or bursts from this target. We have also analyzed three shorter
serendipitous 1.4 GHz radio observations of the source taken with the 64-m
Parkes telescope during the 2006 bursting period. We detected no radio emission
from PSR J1846-0258 in either the Green Bank or Parkes datasets. We place an
upper limit of 4.9 \mu Jy on coherent pulsed emission from PSR J1846-0258 based
on the 2007 November 2 observation, and an upper limit of 27 \mu Jy around the
time of the X-ray bursts. Serendipitously, we observed radio pulses from the
nearby RRAT J1846-02, and place a 3\sigma confidence level upper limit on its
period derivative of 1.7 * 10^{-13}, implying its surface dipole magnetic field
is less than 2.6 * 10^{13} G.Comment: 15 pages, 2 figures, submitted to Ap
Does tiny-scale atomic structure exist in the interstellar medium ?
We report on preliminary results from the recent multi-epoch neutral hydrogen
absorption measurements toward three pulsars, B0823+26, B1133+16 and B2016+28,
using the Arecibo telescope. We do not find significant variations in optical
depth profiles over periods of 0.3 and 9--10 yr, or on spatial scales of 10--20
and 70--85 AU. The large number of non detections of the tiny scale atomic
structure suggests that the AU-sized structure is not ubiquitous in the
interstellar medium and could be quite a rare phenomenon.Comment: Accepted by ApJ Letters, 5 pages, 2 figure
Detection of Gravitational Lensing in the Cosmic Microwave Background
Gravitational lensing of the cosmic microwave background (CMB), a
long-standing prediction of the standard cosmolgical model, is ultimately
expected to be an important source of cosmological information, but first
detection has not been achieved to date. We report a 3.4 sigma detection, by
applying quadratic estimator techniques to all sky maps from the Wilkinson
Microwave Anisotropy Probe (WMAP) satellite, and correlating the result with
radio galaxy counts from the NRAO VLA Sky Survey (NVSS). We present our
methodology including a detailed discussion of potential contaminants. Our
error estimates include systematic uncertainties from density gradients in
NVSS, beam effects in WMAP, Galactic microwave foregrounds, resolved and
unresolved CMB point sources, and the thermal Sunyaev-Zeldovich effect.Comment: 27 pages, 20 figure
An upper limit on anomalous dust emission at 31 GHz in the diffuse cloud [LPH96]201.663+1.643
[LPH96]201.663+1.643, a diffuse H{\sc ii} region, has been reported to be a
candidate for emission from rapidly spinning dust grains. Here we present
Cosmic Background Imager (CBI) observations at 26-36 GHz that show no evidence
for significant anomalous emission. The spectral index within the CBI band, and
between CBI and Effelsberg data at 1.4/2.7 GHz, is consistent with optically
thin free-free emission. The best-fitting temperature spectral index from 2.7
to 31 GHz, , is close to the theoretical value,
for K. We place an upper limit of 24% ~ (2\sigma)
for excess emission at 31 GHz as seen in a 6\arcmin FWHM beam. Current
spinning dust models are not a good fit to the spectrum of LPH96. No polarized
emission is detected in the CBI data with an upper limit of 2% on the
polarization fraction.Comment: 5 pages, 3 figures, submitted to ApJ
Is self always prioritised? Attenuating the ownership self-reference effect in memory
The current study demonstrates the abolishment of the Ownership Self Reference Effect (OSRE) when elaborate details of a distant other-referent are provided. In a 2 (High versus Low information) × 2 (Self versus Other) experimental design, we tested the capacity for the SRE to be modulated with social saliency. Using a well-established ownership paradigm (Collard et al., 2020; Cunningham et al., 2008; Sparks et al., 2016), when the other was made socially salient (i.e. details and characteristics about the other were provided to the participant prior to encoding), no SRE emerged, such that self-owned and other-owned items were recalled with comparable accuracy. In contrast, when the other was not salient (i.e., no details about them were provided), participants accurately recalled a higher proportion of self-owned items, demonstrating a typical SRE in source memory. The degree of self- or other- referencing was not related to measured variables of closeness, similarity or shared traits with the other. Although the SRE is an established and robust effect, the findings of the current study illustrate critical circumstances in which the self is no longer prioritised above the other. In line with our predictions, we suggest that the self has automatic attributed social salience (e.g. through ownership) and that enhancing social salience by elaborating details of the other, prioritisation can expand to encapsulate an other beyond the self and influence incidental memory. [Abstract copyright: Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.
A practical guide for the study of human and murine sebaceous glands in situ
The skin of most mammals is characterised by the presence of sebaceous glands (SGs), whose predominant constituent cell population is sebocytes, that is, lipid-producing epithelial cells, which develop from the hair follicle. Besides holocrine sebum production (which contributes 90% of skin surface lipids), multiple additional SG functions have emerged. These range from antimicrobial peptide production and immunomodulation, via lipid and hormone synthesis/metabolism, to the provision of an epithelial progenitor cell reservoir. Therefore, in addition to its involvement in common skin diseases (e.g. acne vulgaris), the unfolding diversity of SG functions, both in skin health and disease, has raised interest in this integral component of the pilosebaceous unit. This practical guide provides an introduction to SG biology and to relevant SG histochemical and immunohistochemical techniques, with emphasis placed on in situ evaluation methods that can be easily employed. We propose a range of simple, established markers, which are particularly instructive when addressing specific SG research questions in the two most commonly investigated species in SG research, humans and mice. To facilitate the development of reproducible analysis techniques for the in situ evaluation of SGs, this methods review concludes by suggesting quantitative (immuno-)histomorphometric methods for standardised SG evaluation
The SNR G106.3+2.7 and its Pulsar Wind Nebula: relics of triggered star formation in a complex environment
We propose that the pulsar nebula associated with the pulsar J2229+6114 and
the supernova remnant (SNR) G106.3+2.7 are the result of the same supernova
explosion. The whole structure is located at the edge of an HI bubble with
extended regions of molecular gas inside. The radial velocities of both the
atomic hydrogen and the molecular material suggest a distance of 800 pc. At
this distance the SNR is 14 pc long and 6 pc wide. Apparently the bubble was
created by the stellar wind and supernova explosions of a group of stars in its
center which also triggered the formation of the progenitor star of G106.3+2.7.
The progenitor star exploded at or close to the current position of the pulsar,
which is at one end of the SNR rather than at its center. The expanding shock
wave of the supernova explosion created a comet shaped supernova remnant by
running into dense material and then breaking out into the inner part of the HI
bubble. A synchrotron nebula with a shell-like structure (the ``Boomerang'') of
length 0.8 pc was created by the pulsar wind interacting with the dense ambient
medium. The expanding shock wave created an HI shell of mass 0.4 Msun around
this nebula by ionizing the atomic hydrogen in its vicinity.Comment: 10 pages, Latex, with aastex and emulateapj5, 5 figures. ApJ,
accepted, scheduled for the v560 n1 p1 Oct 10, 2001 issu
Profiling of Glycan Receptors for Minute Virus of Mice in Permissive Cell Lines Towards Understanding the Mechanism of Cell Recognition
The recognition of sialic acids by two strains of minute virus of mice (MVM), MVMp (prototype) and MVMi (immunosuppressive), is an essential requirement for successful infection. To understand the potential for recognition of different modifications of sialic acid by MVM, three types of capsids, virus-like particles, wild type empty (no DNA) capsids, and DNA packaged virions, were screened on a sialylated glycan microarray (SGM). Both viruses demonstrated a preference for binding to 9-O-methylated sialic acid derivatives, while MVMp showed additional binding to 9-O-acetylated and 9-O-lactoylated sialic acid derivatives, indicating recognition differences. The glycans recognized contained a type-2 Galβ1-4GlcNAc motif (Neu5Acα2-3Galβ1-4GlcNAc or 3′SIA-LN) and were biantennary complex-type N-glycans with the exception of one. To correlate the recognition of the 3′SIA-LN glycan motif as well as the biantennary structures to their natural expression in cell lines permissive for MVMp, MVMi, or both strains, the N- and O-glycans, and polar glycolipids present in three cell lines used for in vitro studies, A9 fibroblasts, EL4 T lymphocytes, and the SV40 transformed NB324K cells, were analyzed by MALDI-TOF/TOF mass spectrometry. The cells showed an abundance of the sialylated glycan motifs recognized by the viruses in the SGM and previous glycan microarrays supporting their role in cellular recognition by MVM. Significantly, the NB324K showed fucosylation at the non-reducing end of their biantennary glycans, suggesting that recognition of these cells is possibly mediated by the Lewis X motif as in 3′SIA-LeX identified in a previous glycan microarray screen
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