499 research outputs found
Fast motility of isolated mammalian auditory sensory cells
AbstractAuditory sensory cells (hair cells) are responsible for sound transduction in the cochlea of the inner ear. In the presence of a longitudinal a.c. field isolated living outer hair cells showed reversible motile responses. They followed the stimulus up to at least 1 kHz. Control experiments in the presence of cytochalasin B, phalloidin and dinitrophenol excluded actomyosin as a molecular basis of the high frequency motility. The results suggest, that outer hair cells might amplify sound-induced oscillations in the inner ear and thus increase sensitivity and frequency selectivity of hearing
Free radical scavenging reverses fructose-induced salt-sensitive hypertension
We have previously reported that a moderate dietary supplementation of 20% fructose but not glucose leads to a salt-sensitive hypertension related to increased proximal sodium-hydrogen exchanger activity and increased renal sodium retention. We also found that while high salt increased renal nitric oxide formation, this was retarded in the presence of fructose intake. We hypothesized that at least part of the pathway leading to fructose-induced salt-sensitive hypertension could be due to fructose-induced formation of reactive oxygen species and inappropriate stimulation of renin secretion, all of which would contribute to an increase in blood pressure. We found that both 20% fructose intake and a high-salt diet stimulated 8-isoprostane excretion. The superoxide dismutase (SOD) mimetic tempol significantly reduced this elevated excretion. Next, we placed rats on a high-salt diet (4%) for 1 week in combination with normal rat chow or 20% fructose with or without chronic tempol administration. A fructose plus high-salt diet induced a rapid increase (15 mmHg) in systolic blood pressure and reversed high salt suppression of plasma renin activity. Tempol treatment reversed the pressor response and restored high salt suppression of renin. We conclude that fructose-induced salt-sensitive hypertension is driven by increased renal reactive oxygen species formation associated with salt retention and an enhanced renin-angiotensin system
The Compact Nucleus of the Deep Silicate Absorption Galaxy NGC 4418
High resolution, Hubble Space Telescope (HST) near-infrared and Keck
mid-infrared images of the heavily extinguished, infrared luminous galaxy NGC
4418 are presented. These data make it possible to observe the imbedded
near-infrared structure on scales of 10-20 pc, and to constrain the size of the
mid-infrared emitting region. The 1.1-2.2 um data of NGC 4418 show no clear
evidence of nuclear star clusters or of a reddened active galactic nucleus.
Instead, the nucleus of the galaxy consists of a ~100-200 pc linear structure
with fainter structures extending radially outward. The near-infrared colors of
the linear feature are consistent with a 10-300 Myr starburst suffering
moderate levels (few magnitudes) of visual extinction. At 7.9-24.5 um, NGC 4418
has estimated size upper limits in the range of 30-80 pc. These dimensions are
consistent with the highest resolution radio observations obtained to date of
NGC 4418, as well as the size of 50-70 pc expected for a blackbody with a
temperature derived from the 25 um, 60 um, and 100 um flux densities of the
galaxy. Further, a spectral energy distribution constructed from the
multi-wavelength mid-infrared observations show the strong silicate absorption
feature at 10 um, consistent with previous mid-infrared observations of NGC
4418. An infrared surface brightness of 2.1x10^13 L_sun kpc^-2 is derived for
NGC 4418. Such a value, though consistent with the surface brightness of warm
ultraluminous infrared galaxies (ULIGs: L_IR [8-1000 um] >~ 10^12 L_sun) such
as IRAS 05189-2524 and IRAS 08572+3915, is not large enough to distinguish NGC
4418 as a galaxy powered by an Active Galactic Nucleus (AGN), as opposed to a
lower surface brightness starburst.Comment: LaTex, 7 pages, including 2 jpg figures and 3 postscript figures, AJ,
in press (May, 2003
Exploring the effects of BCG vaccination in patients diagnosed with tuberculosis: Observational study using the Enhanced Tuberculosis Surveillance system.
BACKGROUND: Bacillus Calmette-Guérin (BCG) is one of the most widely-used vaccines worldwide. BCG primarily reduces the progression from infection to disease, however there is evidence that BCG may provide additional benefits. We aimed to investigate whether there is evidence in routinely-collected surveillance data that BCG vaccination impacts outcomes for tuberculosis (TB) cases in England. METHODS: We obtained all TB notifications for 2009-2015 in England from the Enhanced Tuberculosis surveillance system. We considered five outcomes: All-cause mortality, death due to TB (in those who died), recurrent TB, pulmonary disease, and sputum smear status. We used logistic regression, with complete case analysis, to investigate each outcome with BCG vaccination, years since vaccination and age at vaccination, adjusting for potential confounders. All analyses were repeated using multiply imputed data. RESULTS: We found evidence of an association between BCG vaccination and reduced all-cause mortality (aOR:0.76 (95%CI 0.64-0.89), P:0.001) and weak evidence of an association with reduced recurrent TB (aOR:0.90 (95%CI 0.81-1.00), P:0.056). Analyses using multiple imputation suggested that the benefits of vaccination for all-cause mortality were reduced after 10 years. CONCLUSIONS: We found that BCG vaccination was associated with reduced all-cause mortality in people with TB although this benefit was less pronounced more than 10 years after vaccination. There was weak evidence of an association with reduced recurrent TB
VLBA Continuum and H I Absorption Observations of the Ultra-Luminous Infrared Galaxy IRAS 17208-0014
We present phase-referenced VLBI observations of the radio continuum emission
from, and the neutral hydrogen 21 cm absorption toward, the Ultra-Luminous
Infrared Galaxy IRAS 17208-0014. The observations were carried out at 1362 MHz
using the Very Long Baseline Array, including the phased Very Large Array as an
element. The high-resolution radio continuum images reveal a nuclear starburst
region in this galaxy, which is composed of diffuse emission approximately 670
x 340 pc on the plane of the sky, and a number of compact sources. These
sources are most likely to be clustered supernova remnants and/or luminous
radio supernovae. Their brightness temperatures range over (2.2-6.6) x 10^{5}
K, with radio spectral luminosities between (1-10) x 10^{21} W Hz^{-1}. The
total VLBI flux density of the starburst region is ~52 mJy, which is about 50%
of the total flux density detected with the VLA at arcsecond resolution. For
this galaxy, we derive a massive star formation rate of ~84pm13 M{_\odot}
yr^{-1}, and a supernova rate of ~4pm1 yr^{-1}. H I absorption is detected in
multiple components with optical depths ranging between 0.3 and 2.5, and
velocity widths between 58 and 232 km s^{-1}. The derived column densities,
assuming T_{s}=100 K, range over (10-26) x 10^{21} cm^{-2}. The H I absorption
shows a strong velocity gradient of 453 km s^{-1} across 0.36 arcsec (274 pc).
Assuming Keplerian motion, the enclosed dynamical mass is about 2.3 x 10^9
sin^{-2}i M{_\odot}, comparable to the enclosed dynamical mass estimated from
CO observations.Comment: 26 pages total, 6 figures. ApJ accepted. To appear in the April 1,
2003 issue of ApJ. For a version with better images, see
http://www.aoc.nrao.edu/~emomjian/IRAS.p
Neutrino Spin Transitions and the Violation of the Equivalence Principle
The violation of the equivalence principle (VEP) causing neutrino
oscillations is of current interest. We study here the possibility of not only
flavor oscillation but spin flavor oscillation of ultra high energy ( 1
PeV) neutrinos emanating from AGN due to VEP and due to the presence of a large
magnetic field ( 1 Tesla) in AGN. In particular we look at the resonance
spin flavor conversion driven by the AGN potential. Interesting bounds on the
transition magnetic moment of neutrinos may therefore be obtained.Comment: Latex, 12 pages, no figures. To appear in Journal of Physics G:
Nuclear and Particle Physics. Two references adde
Engaging with civil society to improve access to LTBI screening for new migrants in England: a qualitative study
SETTING: The latent tuberculous infection (LTBI) programme in England, UK, offers testing and treatment to new migrants from high tuberculosis incidence countries. However, the rates of LTBI testing, treatment acceptance and completion are suboptimal and appropriate access should be improved.
OBJECTIVE: To gain insight from the community, community-based organisations (CBOs) and public sector stakeholders on interventions that facilitate collaboration to improve health care outreach and delivery.
DESIGN: Three stakeholder meetings and five focus group discussions were held using thematic analysis to identify themes arising from participants' perspectives.
RESULTS: Four overarching themes emerged from the discussions. These were related to capacity of service providers, collaboration between stakeholders, migrant cultures and trust between migrants and service providers, and highlighted the complementary skill sets that different sectors bring to the collaboration, as well as the barriers that need to be surmounted. Stigma could be reduced by making LTBI testing routine. Community members could act as champions of health promotion to raise awareness on LTBI testing, and provide a bridge between communities and primary care services.
CONCLUSION: Public service providers, community members and CBOs are willing to collaborate to support primary care delivery of testing for LTBI and other communicable and non-communicable diseases. Policy and commissioning support are needed to facilitate this collaboration
Extracting Axial Depth and Trajectory Trend Using Astigmatism, Gaussian Fitting, and CNNs for Protein Tracking
Accurate analysis of vesicle trafficking in live cells is challenging for a number of reasons: varying appearance, complex protein movement patterns, and imaging conditions. To allow fast image acquisition, we study how employing an astigmatism can be utilized for obtaining additional information that could make tracking more robust. We present two approaches for measuring the z position of individual vesicles. Firstly, Gaussian curve fitting with CNN-based denoising is applied to infer the absolute depth around the focal plane of each localized protein. We demonstrate that adding denoising yields more accurate estimation of depth while preserving the overall structure of the localized proteins. Secondly, we investigate if we can predict using a custom CNN architecture the axial trajectory trend. We demonstrate that this method performs well on calibration beads data without the need for denoising. By incorporating the obtained depth information into a trajectory analysis, we demonstrate the potential improvement in vesicle tracking
A feasibility study evaluating the uptake, effectiveness and acceptability of routine screening of pregnant migrants for latent tuberculosis infection in antenatal care: a research protocol
INTRODUCTION: Globally, tuberculosis (TB) is a leading cause of death in women of reproductive age and there is high risk of reactivation of latent tuberculosis infection (LTBI) in pregnancy. The uptake of routine screening of migrants for LTBI in the UK in primary care is low. Antenatal care is a novel setting which could improve uptake and can lend insight into the feasibility and acceptability of offering opt-out screening for LTBI. METHODS AND ANALYSIS: This is an observational feasibility study with a nested qualitative component. The setting will be the antenatal clinics in three hospitals in East London, UK . Inclusion criteria are pregnant migrant women aged 16-35 years attending antenatal clinics who are from countries with a TB incidence of greater than 150/100 000 including sub-Saharan Africa, and who have been in the UK for less than 5 years. Participants will be offered LTBI screening with an opt-out interferon gamma release assay blood test, and be invited to complete a questionnaire. Both participants and healthcare providers will be invited to participate in semistructured interviews or focus groups to evaluate understanding, feasibility and acceptability of routine opt-out LTBI screening. The primary analysis will focus on estimating the uptake of the screening programme along with the corresponding 95% CI. Secondary analysis will focus on estimating the test positivity. Qualitative analysis will evaluate the acceptability of offering routine opt-out LTBI screening to participants and healthcare providers. ETHICS AND DISSEMINATION: The study has received the following approvals: Health Research Authority (IRAS 247388) and National Health Service Ethics Committee (19/LO/0557). The results will be made available locally to antenatal clinics and primary care physicians, nationally to NHS England and Public Health England and internationally through conferences and journals. TRIAL REGISTRATION NUMBER: NCT04098341
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