2,693 research outputs found
The physiological bases of hidden noise-induced hearing loss: protocol for a functional neuroimaging study
Background: Rodent studies indicate that noise exposure can cause permanent damage to synapses between inner hair cells and high-threshold auditory nerve fibers, without permanently altering threshold sensitivity. These demonstrations of what is commonly known as âhidden hearing lossâ have been confirmed in several rodent species, but the implications for human hearing are unclear.
Objective: Our Medical Research Council (MRC) funded programme aims to address this unanswered question, by investigating functional consequences of the damage to the human peripheral and central auditory nervous system that results from cumulative lifetime noise exposure. Behavioral and neuroimaging techniques are being used in a series of parallel studies aimed at detecting hidden hearing loss in humans. The planned neuroimaging study aims to (1) identify central auditory biomarkers associated with hidden hearing loss, (2) investigate if there are any additive contributions from tinnitus or diminished sound tolerance, which are often comorbid with hearing problems, and (3) explore the relation between subcortical functional Magnetic Resonance Imaging (fMRI) measures and the auditory brainstem response (ABR).
Methods: Individuals aged 25 to 40 years with pure tone hearing thresholds †20 dB HL over the range 500 Hz to 8 kHz and no contraindications for MRI or signs of ear disease will be recruited into the study. Lifetime noise exposure will be estimated using an in-depth structured interview. Auditory responses throughout the central auditory system will be recorded using ABR and fMRI. Analyses will focus predominantly on correlations between lifetime noise exposure and auditory response characteristics.
Results: This article reports the study protocol. The programme grant was awarded in July 2013. Enrollment for the study described in this protocol commenced in February 2017 and was completed in December 2017. Results are expected in 2018.
Conclusions: This challenging and comprehensive study will have the potential to impact diagnostic procedures for hidden hearing loss, enabling early identification of noise-induced auditory damage via the detection of changes in central auditory processing. Consequently, this will generate the opportunity to give personalized advice regarding provision of ear defense and monitoring of further damage, thus reducing the incidence of noise-induced hearing loss
Recommended from our members
Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour
Funder: European Social Fund; doi: http://dx.doi.org/10.13039/501100004895AbstractCoral reefs are renowned for the complexity of their habitat structures and their resulting ability to host more species per unit area than any another marine ecosystem. Dedicated cleaner fish, which acquire all their food resources through client interactions, rely on both the habitat structures (by using topological cleaning stations) and the wide diversity of fish species available on coral reefs, to function. As a result of natural and anthropogenic threats, coral reef habitat structures and their complexity are being lostâdespite this threat it is unclear how important reef geometry is to key ecological interactions, like cleaning. Using an established Caribbean reef study site, three-dimensional constructions of discrete coral heads were used to investigate how fine-scale structural complexity traits (structural complexityâmeasured by rugosity and vector dispersionâheight, volume, surface area, percentage live coral cover and refuge availability) relate to cleaner occupancy, abundance and their cleaning interactions with clients. Coral height was a particularly important trait for cleaning, correlating with both the occurrence of cleaning stations on a reef, and with increased cleaning durations and reduced cleaning frequencies/rates. Cleaning stations were also more structurally complex than non-cleaning coral heads, and the increased availability of uneven surfaces (creating cracks and crevices) and refuge availability linked with increased cleaning durations/rates. By understanding habitat features important to cleaner fish on a typical Caribbean fringing reef, we can gain a better understanding of how important reef geometry might be for governing the occurrence and dynamics of such mutualisms.</jats:p
Scintillator-based ion beam profiler for diagnosing laser-accelerated ion beams
Next generation intense, short-pulse laser facilities require new high repetition rate diagnostics for the detection of ionizing radiation. We have designed a new scintillator-based ion beam profiler capable of measuring the ion beam transverse profile for a number of discrete energy ranges. The optical response and emission characteristics of four common plastic scintillators has been investigated for a range of proton energies and fluxes. The scintillator light output (for 1 MeV > Ep < 28 MeV) was found to have a non-linear scaling with proton energy but a linear response to incident flux. Initial measurements with a prototype diagnostic have been successful, although further calibration work is required to characterize the total system response and limitations under the high flux, short pulse duration conditions of a typical high intensity laser-plasma interaction
An Early Cambrian Rift to Post-Rift Transition in the Cordillera of Western North America
The upper Proterozoic and lower Palaeozoic wedge of miogeoclinal strata in the North American Cordillera is widely regarded as evidence for a proto-Pacific passive margin. The rifting history of this margin appears to have been protracted, possibly spanning more than 200 Myr in a tectonic setting that is not well understood. Quantitative subsidence analyses of lower Palaeozoic strata between British Columbia and Utah, however, provide indirect evidence that the transition from rifting to post-rift cooling occurred within a relatively short interval of time, although probably not synchronously, between 600 and 555 Myr. This age is significantly younger than that implied in previous studies. We describe here new field data, which, together with published geological data, provide direct evidence of a latest Proterozoic or early Cambrian age for the rift to post-rift transition. The data support recent arguments for widespread initiation of passive margins around the edge of the North American craton close to the Cambrian-Precambrian boundary
The braincase and jaws of a Devonian 'acanthodian' and modern gnathostome origins.
Modern gnathostomes (jawed vertebrates) emerged in the early Palaeozoic era, but this event remains unclear owing to a scant early fossil record. The exclusively Palaeozoic acanthodians are possibly the earliest gnathostome group and exhibit a mosaic of shark- and bony fish-like characters that has long given them prominence in discussions of early gnathostome evolution. Their relationships with modern gnathostomes have remained mysterious, partly because their un-mineralized endoskeletons rarely fossilized. Here I present the first-known braincase of an Early Devonian (approximately 418-412 Myr bp) acanthodian, Ptomacanthus anglicus, and re-evaluate the interrelationships of basal gnathostomes. Acanthodian braincases have previously been represented by a single genus, Acanthodes, which occurs more than 100 million years later in the fossil record. The braincase of Ptomacanthus differs radically from the osteichthyan-like braincase of Acanthodes in exhibiting several plesiomorphic features shared with placoderms and some early chondrichthyans. Most striking is its extremely short sphenoid region and its jaw suspension, which displays features intermediate between some Palaeozoic chondrichthyans and osteichthyans. Phylogenetic analysis resolves Ptomacanthus as either the most basal chondrichthyan or as the sister group of all living gnathostomes. These new data alter earlier conceptions of basal gnathostome phylogeny and thus help to provide a more detailed picture of the acquisition of early gnathostome characters
An evaluation of enteral nutrition practices and nutritional provision in children during the entire length of stay in critical care
<b>Background</b>
Provision of optimal nutrition in children in critical care is often challenging. This study evaluated exclusive enteral nutrition (EN) provision practices and explored predictors of energy intake and delay of EN advancement in critically ill children.<p></p>
<b>Methods</b>
Data on intake and EN practices were collected on a daily basis and compared against predefined targets and dietary reference values in a paediatric intensive care unit. Factors associated with intake and advancement of EN were explored.<p></p>
<b>Results</b>
Data were collected from 130 patients and 887 nutritional support days (NSDs). Delay to initiate EN was longer in patients from both the General Surgical and congenital heart defect (CHD) Surgical groups [Median (IQR); CHD Surgical group: 20.3 (16.4) vs General Surgical group: 11.4 (53.5) vs Medical group: 6.5 (10.9) hours; p <= 0.001]. Daily fasting time per patient was significantly longer in patients from the General Surgical and CHD Surgical groups than those from the Medical group [% of 24 h, Median (IQR); CHD Surgical group: 24.0 (29.2) vs General Surgical group: 41.7 (66.7) vs Medical group: 9.4 (21.9); p <= 0.001]. A lower proportion of fluids was delivered as EN per patient (45% vs 73%) or per NSD (56% vs 73%) in those from the CHD Surgical group compared with those with medical conditions. Protein and energy requirements were achieved in 38% and 33% of the NSDs. In a substantial proportion of NSDs, minimum micronutrient recommendations were not met particularly in those patients from the CHD Surgical group. A higher delivery of fluid requirements (p < 0.05) and a greater proportion of these delivered as EN (p < 0.001) were associated with median energy intake during stay and delay of EN advancement. Fasting (31%), fluid restriction (39%) for clinical reasons, procedures requiring feed cessation and establishing EN (22%) were the most common reasons why target energy requirements were not met.<p></p>
<b>Conclusions</b>
Provision of optimal EN support remains challenging and varies during hospitalisation and among patients. Delivery of EN should be prioritized over other "non-nutritional" fluids whenever this is possible.<p></p>
Generation of Ultrastable Microwaves via Optical Frequency Division
There has been increased interest in the use and manipulation of optical
fields to address challenging problems that have traditionally been approached
with microwave electronics. Some examples that benefit from the low
transmission loss, agile modulation and large bandwidths accessible with
coherent optical systems include signal distribution, arbitrary waveform
generation, and novel imaging. We extend these advantages to demonstrate a
microwave generator based on a high-Q optical resonator and a frequency comb
functioning as an optical-to-microwave divider. This provides a 10 GHz
electrical signal with fractional frequency instability <8e-16 at 1 s, a value
comparable to that produced by the best microwave oscillators, but without the
need for cryogenic temperatures. Such a low-noise source can benefit radar
systems, improve the bandwidth and resolution of communications and digital
sampling systems, and be valuable for large baseline interferometry, precision
spectroscopy and the realization of atomic time
The case for home based telehealth in pediatric palliative care: a systematic review
Background: Over the last decade technology has rapidly changed the ability to provide home telehealth services. At the same time, pediatric palliative care has developed as a small, but distinct speciality. Understanding the experiences of providing home telehealth services in pediatric palliative care is therefore important
Accuracy of Digital Breast Tomosynthesis for Depicting Breast Cancer Subgroups in a UK Retrospective Reading Study (TOMMY Trial)
Purpose
To compare the diagnostic performance of two-dimensional (2D) mammography, 2D mammography plus digital breast tomosynthesis (DBT), and synthetic 2D mammography plus DBT in depicting malignant radiographic features.
Materials and Methods
In this multicenter, multireader, retrospective reading study (the TOMMY trial), after written informed consent was obtained, 8869 women (age range, 29â85 years; mean, 56 years) were recruited from July 2011 to March 2013 in an ethically approved study. From these women, a reading dataset of 7060 cases was randomly allocated for independent blinded review of (a) 2D mammography images, (b) 2D mammography plus DBT images, and (c) synthetic 2D mammography plus DBT images. Reviewers had no access to results of previous examinations. Overall sensitivities and specificities were calculated for younger women and those with dense breasts.
Results
Overall sensitivity was 87% for 2D mammography, 89% for 2D mammography plus DBT, and 88% for synthetic 2D mammography plus DBT. The addition of DBT was associated with a 34% increase in the odds of depicting cancer (odds ratio [OR] = 1.34, P = .06); however, this level did not achieve significance. For patients aged 50â59 years old, sensitivity was significantly higher (P = .01) for 2D mammography plus DBT than it was for 2D mammography. For those with breast density of 50% or more, sensitivity was 86% for 2D mammography compared with 93% for 2D mammography plus DBT (P = .03). Specificity was 57% for 2D mammography, 70% for 2D mammography plus DBT, and 72% for synthetic 2D mammography plusmDBT. Specificity was significantly higher than 2D mammography (P < .001in both cases) and was observed for all subgroups (P < .001 for all cases).
Conclusion
The addition of DBT increased the sensitivity of 2D mammography in patients with dense breasts and the specificity of 2D mammography for all subgroups. The use of synthetic 2D DBT demonstrated performance similar to that of standard 2D mammography with DBT. DBT is of potential benefit to screening programs, particularly in younger women with dense breasts.
© RSNA, 2015The TOMMY Trial (a comparison of digital breast tomosynthesis with mammography in the UK Breast Screening Programme) was supported by the NIHR Health Technology Assessment Programme.This is the final published version of the article. It was originally published in Radiology (Gilbert et al., Radiology, 2015, doi:10.1148/radiol.2015142566). The final version is available at http://dx.doi.org/10.1148/radiol.201514256
Regulation of pituitary MT1 melatonin receptor expression by gonadotrophin-releasing hormone (GnRH) and early growth response factor-1 (Egr-1) : in vivo and in vitro studies
Copyright: © 2014 Bae et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC; grant BB/F020309/1; http://www.bbsrc.ac.uk/home/home.aspx). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
- âŠ