3,821 research outputs found
Surface Morphology of Human Airway Mucosa: Normal, Carcinoma or Cystic Fibrosis
The study presents preliminary qualitative findings of an investigation of grossly normal main and lobar bronchi at sites distant to well circumscribed tumour (n=15), adjacent to tumour (n=5) or of airways obtained during heart/lung transplantation in patients with cystic fibrosis (CF, n=3). In the normal airways the surface epithelium was on average 50 m thick, pseudostratified and rested on a roughly contoured basement membrane. A variety of cell types were identified although many were obscured by a dense covering of cilia, occasionally interrupted by foci of squamous metaplasia. Submucosal gland structure was observed in chance vertical fractures of the airway wall. Tissue adjacent to tumour showed sloughing, squamous metaplasia, pleomorphism and cell surface projections of stubby microvilli or tortuous microridges. The surface morphology of the three CF patients showed no feature unique to the condition, albeit secretions were found adherent to surface lining associated with isolated bacteria and groups of free cells (probably lymphocytes). In each of the three cases the epithelial surface was densely ciliated, interspersed with mucous (i.e., goblet) cells. Submucosal gland collecting ducts had dilated lumena
An analysis of ultraviolet spectra of Extreme Helium Stars and new clues to their origins
Abundances of about 18 elements including the heavy elements Y and Zr are
determined from Hubble Space Telescope Space Telescope Imaging Spectrograph
ultraviolet spectra of seven extreme helium stars (EHes): LSE 78, BD+10 2179,
V1920 Cyg, HD 124448, PV Tel, LS IV -1 2, and FQ Aqr. New optical spectra of
the three stars -- BD+10 2179, V1920 Cyg, and HD 124448 were analysed. The
abundance analyses is done using LTE line formation and LTE model atmospheres
especially constructed for these EHe stars. The stellar parameters derived from
an EHe's UV spectrum are in satisfactory agreement with those derived from its
optical spectrum. Adopted abundances for the seven EHes are from a combination
of the UV and optical analyses. Published results for an additional ten EHes
provide abundances obtained in a nearly uniform manner for a total of 17 EHes,
the largest sample on record. The initial metallicity of an EHe is indicated by
the abundance of elements from Al to Ni; Fe is adopted to be the representative
of initial metallicity. Iron abundances range from approximately solar to about
one-hundredth of solar. Clues to EHe evolution are contained within the H, He,
C, N, O, Y, and Zr abundances. Two novel results are (i) the O abundance for
some stars is close to the predicted initial abundance yet the N abundance
indicates almost complete conversion of initial C, N, and O to N by the
CNO-cycles; (ii) three of the seven stars with UV spectra show a strong
enhancement of Y and Zr attributable to an s-process. The observed compositions
are discussed in light of expectations from accretion of a He white dwarf by a
CO white dwarf.Comment: 126 pages, 15 figures, 20 Tables, accepted for publication in the Ap
Intraorbital foreign body detection and localisation by radiographers: a preliminary JAFROC observer performance study
Introduction - The purpose of this study was to run a preliminary investigation to establish if a short course of learning would increase radiographers’ performance in intraorbital foreign body (IOFB) detection and localisation on pre-magnetic resonance imaging (MRI) orbital computed radiographs (CR).
Method - A multi-reader multi-case (MRMC) human observer study was performed. Fifteen radiographers from 5 hospitals participated. Each radiographer reviewed a pre- and post-training image bank and was instructed to identify the presence or absence of IOFBs, indicating the lesion location on each case whilst scoring the detection using a confidence index on a 5-point scale, for 30 orbital radiographs. The results were analysed using a Jackknife free-response receiver operating characteristic (JAFROC2 equal weighted) methodology.
Results -The performance of the radiographers demonstrated a statistically significant difference after a short period of training in the detection of IOFBs on orbital radiographs (F (1,14)= 12.99, df = 14.0, p = 0.0029). The JAFROC2 analysis averaged figure of merit (FOM) for the radiographers was 0.818 (95% CI 0.769, 0.867) pre-training and 0.920 (95% CI 0.891, 0.950) post-training.
Conclusion - These results suggest that with a short programme of learning in image interpretation for IOFBs in orbital radiographs, radiographers should be able to achieve a high level of accuracy in the identification and localisation of IOFBs prior to MRI examination
Mapping heterogeneous research infrastructure metadata into a unified catalogue for use in a generic virtual research environment
Virtual Research Environments (VREs), also known as science gateways or virtual laboratories, assist researchers
in data science by integrating tools for data discovery, data retrieval, workflow management
and researcher collaboration, often coupled with a specific computing infrastructure. Recently, the push
for better open data science has led to the creation of a variety of dedicated research infrastructures
(RIs) that gather data and provide services to different research communities, all of which can be used
independently of any specific VRE. There is therefore a need for generic VREs that can be coupled
with the resources of many different RIs simultaneously, easily customised to the needs of specific
communities. The resource metadata produced by these RIs rarely all adhere to any one standard
or vocabulary however, making it difficult to search and discover resources independently of their
providers without some translation into a common framework. Cross-RI search can be expedited by
using mapping services that harvest RI-published metadata to build unified resource catalogues, but
the development and operation of such services pose a number of challenges.
In this paper, we discuss some of these challenges and look specifically at the VRE4EIC Metadata
Portal, which uses X3ML mappings to build a single catalogue for describing data products and other
resources provided by multiple RIs. The Metadata Portal was built in accordance to the e-VRE Reference
Architecture, a microservice-based architecture for generic modular VREs, and uses the CERIF standard
to structure its catalogued metadata. We consider the extent to which it addresses the challenges of
cross-RI search, particularly in the environmental and earth science domain, and how it can be further
augmented, for example to take advantage of linked vocabularies to provide more intelligent semantic
search across multiple domains of discourse
Response of Laryngeal and Tracheo-Bronchial Surface Lining to Inhaled Cigarette Smoke in Normal and Vitamin A-Deficient Rats: A Scanning Electron Microscopic Study.
The effects on surface morphology of airway epithelium of cigarette smoke (CS) inhalation alone (experiments one and two) or of CS in combination with hypovitaminosis A (experiment two) was investigated using specific pathogen free rats. Eight morphologically distinct cell types were distinguished overall. Apart from atypical squamous lesions each of the other cell types could be found in varying proportions in all experimental groups. CS alone caused an increase in the frequency with which intra-lumenal mucus was seen and an increase in the occurrence of secretory cells of types IV (i.e.,\u27merocrine\u27) and V (i.e.,\u27apocrine\u27). In experiment one, the area of trachea covered by cilia as determined by point counting increased significantly (P\u3c0.01). Hypovitaminosis A was induced by lowering the dietary intake of vitamin A to a minimum, defined level. Rats showed an approximately 75% decrease in plasma retinol levels and a 95-100% decrease in hepatic stores of vitamin A. At this level, hypovitaminosis A alone had no significant effect on airway epithelial morphology. Foci of squamous metaplasia (squamous cells of type VIIIa) were found in all groups but extensive squamous metaplasia of the larynx and squamous lesions of atypical appearance (type VIIIb) were found only in the vitamin deficient group exposed to CS. The results suggest the synergistic effects of reduced vitamin A and CS may be important in the induction of atypical squamous changes which may predispose the airway to the development of squamous carcinoma
Mode identification from monochromatic amplitude and phase variations for the rapidly pulsating subdwarf B star EC 20338-1925
We obtain time-series spectrophotometry observations at the VLT with the aim
of partially identifying the dominant oscillation modes in the rapidly
pulsating subdwarf B star EC 20338-1925 on the basis of monochromatic amplitude
and phase variations. From the data gathered, we detect four previously known
pulsations with periods near 147, 168, 126 and 140 s and amplitudes between 0.2
and 2.3 % of the star's mean brightness. We also determine the atmospheric
parameters of EC 20338-1925 by fitting our non-LTE model atmospheres to an
averaged combined spectrum. The inferred parameters are Teff = 34,153+-94 K,
log g =5.966+-0.017 and log[N(He)/N(H)] = - 1.642+-0.022, where the uncertainty
estimates quoted refer to the formal fitting errors. Finally, we calculate the
observed monochromatic amplitudes and phases for the periodicities extracted
using least-squares fitting to the light curves obtained for each wavelength
bin. These observed quantities are then compared to the corresponding
theoretical values computed on the basis of dedicated model atmosphere codes
and also taking into account non-adiabatic effects. We find that the quality of
the data is sufficient to identify the dominant pulsation at 146.9 s as a
radial mode, while two of the lower amplitude periodicities must be low-degree
modes with l=0-2. This is the first time that monochromatic amplitudes and
phases have been used for mode identification in a subdwarf B star, and the
results are highly encouraging.Comment: 11 pages. Accepted for publication in Astronomy & Astrophysic
Irreducible characters of GSp(4, q) and dimensions of spaces of fixed vectors
In this paper, we compute the conjugacy classes and the list of irreducible
characters of GSp(4,q), where q is odd. We also determine precisely which
irreducible characters are non-cuspidal and which are generic. These characters
are then used to compute dimensions of certain subspaces of fixed vectors of
smooth admissible non-supercuspidal representations of GSp(4,F), where F is a
non-archimedean local field of characteristic zero with residue field of order
q.Comment: 48 pages, 21 tables. Corrected an error in Table 16 for type V*
representations (theta_11 and theta_12 were switched
Rapid identification of mutations in GJC2 in primary lymphoedema using whole exome sequencing combined with linkage analysis with delineation of the phenotype.
Background: Primary lymphoedema describes a chronic, frequently progressive, failure of lymphatic drainage. This disorder is frequently genetic in origin, and a multigenerational family in which eight individuals developed postnatal lymphoedema of all four limbs was ascertained from the joint Lymphoedema/Genetic clinic at St George's Hospital.
Methods: Linkage analysis was used to determine a locus, and exome sequencing was employed to look for causative variants.
Results: Linkage analysis revealed cosegregation of a 16.1 Mb haplotype on chromosome 1q42 that contained 173 known or predicted genes. Whole exome sequencing in a single affected individual was undertaken, and the search for the causative variant was focused to within the linkage interval. This approach revealed two novel non-synonymous single nucleotide substitutions within the chromosome 1 locus, in NVL and GJC2. NVL and GJC2 were sequenced in an additional cohort of individuals with a similar phenotype and non-synonymous variants were found in GJC2 in four additional families.
Conclusion: This report demonstrates the power of exome sequencing efficiently applied to a traditional positional cloning pipeline in disease gene discovery, and suggests that the phenotype produced by GJC2 mutations is predominantly one of 4 limb lymphoedema
Planet Consumption and Stellar Metallicity Enhancements
The evolution of a giant planet within the stellar envelope of a
main-sequence star is investigated as a possible mechanism for enhancing the
stellar metallicities of the parent stars of extrasolar planetary systems.
Three-dimensional hydrodynamical simulations of a planet subject to impacting
stellar matter indicate that the envelope of a Jupiter-like giant planet can be
completely stripped in the outer stellar convection zone of a solar-mass star.
In contrast, Jupiter-like and less massive Saturn-like giant planets are able
to survive through the base of the convection zone of a 1.22 solar-mass star.
Although strongly dependent on details of planetary interior models, partial or
total dissolution of giant planets can result in significant enhancements in
the metallicity of host stars with masses between about 1.0 and 1.3 solar
masses. The implications of these results with regard to planetary orbital
migration are briefly discussed.Comment: 11 pages, 2 figures, accepted for ApJ Letter
Can HRCT be used as a marker of airway remodelling in children with difficult asthma?
BACKGROUND: Whole airway wall thickening on high resolution computed tomography (HRCT) is reported to parallel thickening of the bronchial epithelial reticular basement membrane (RBM) in adult asthmatics. A similar relationship in children with difficult asthma (DA), in whom RBM thickening is a known feature, may allow the use of HRCT as a non-invasive marker of airway remodelling. We evaluated this relationship in children with DA. METHODS: 27 children (median age 10.5 [range 4.1-16.7] years) with DA, underwent endobronchial biopsy from the right lower lobe and HRCT less than 4 months apart. HRCTs were assessed for bronchial wall thickening (BWT) of the right lower lobe using semi-quantitative and quantitative scoring techniques. The semi-quantitative score (grade 0-4) was an overall assessment of BWT of all clearly identifiable airways in HRCT scans. The quantitative score (BWT %; defined as [airway outer diameter - airway lumen diameter]/airway outer diameter x100) was the average score of all airways visible and calculated using electronic endpoint callipers. RBM thickness in endobronchial biopsies was measured using image analysis. 23/27 subjects performed spirometry and the relationships between RBM thickness and BWT with airflow obstruction evaluated. RESULTS: Median RBM thickness in endobronchial biopsies was 6.7(range 4.6-10.0) microm. Median qualitative score for BWT of the right lower lobe was 1(range 0-1.5) and quantitative score was 54.3 (range 48.2-65.6)%. There was no relationship between RBM thickness and BWT in the right lower lobe using either scoring technique. No relationship was found between FEV1 and BWT or RBM thickness. CONCLUSION: Although a relationship between RBM thickness and BWT on HRCT has been found in adults with asthma, this relationship does not appear to hold true in children with D
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