3,322 research outputs found
Comparative genetic resistance to Ascaridia galli infections of 4 different commercial layer-lines
1. The objective of the study was to compare the establishment and effect of Ascaridia galli infections in 4 different layer-lines.
2. A total of 160 birds comprising 4 different commercial layer-lines, ISA Brown, New Hampshire, Skalborg and a cross of New Hampshire(NH) and Skalborg (Sk), were infected with A. galli eggs. The birds were examined for the presence of parasite eggs and parasites at weeks 3, 6 and 9 post infection (pi).
3. At week 6 pi the chickens of the NH line harboured more larvae compared with the three other lines. The Sk line chickens excreted more A. galli eggs throughout the study compared with the other lines. Female worms in the Sk line were more fecund than the worms in the other lines. Male and female worms recovered from the Sk line at week 9 pi were longer. Male worms recovered from the NH line 6 weeks pi were shorter than male worms from the other lines. Female worms recovered from the NH line were shorter than the female worms from the ISA line and the Sk line. No differences were seen
in weight gain among the 4 lines.
4. The results suggest that genetic factors are involved in the establishment and survival of A. galli in the intestine of layers. Further studies are needed to elucidate the genetic mechanisms behind the observed parasitological findings
Can pathoanatomical pathways of degeneration in lumbar motion segments be identified by clustering MRI findings
Background: Magnetic Resonance Imaging (MRI) is the gold standard for detailed visualisation of spinal pathological and degenerative processes, but the prevailing view is that such imaging findings have little or no clinical relevance for low back pain. This is because these findings appear to have little association with treatment effects in clinical populations, and mostly a weak association with the presence of pain in the general population.However, almost all research into these associations is based on the examination of individual MRI findings, despite its being very common for multiple MRI findings to coexist. Therefore, this proof-of-concept study investigated the capacity of a multivariable statistical method to identify clusters of MRI findings and for those clusters to be grouped into pathways of vertebral degeneration. Methods. This study is a secondary analysis of data from 631 patients, from an outpatient spine clinic, who had been screened for inclusion in a randomised controlled trial. The available data created a total sample pool of 3,155 vertebral motion segments. The mean age of the cohort was 42 years (SD 10.8, range 18-73) and 54% were women.MRI images were quantitatively coded by an experienced musculoskeletal research radiologist using a detailed and standardised research MRI evaluation protocol that has demonstrated high reproducibility. Comprehensive MRI findings descriptive of the disco-vertebral component of lumbar vertebrae were clustered using Latent Class Analysis. Two pairs of researchers, each containing an experienced MRI researcher, then independently categorised the clusters into hypothetical pathoanatomic pathways based on the known histological changes of discovertebral degeneration. Results: Twelve clusters of MRI findings were identified, described and grouped into five different hypothetical pathways of degeneration that appear to have face validity. Conclusions: This study has shown that Latent Class Analysis can be used to identify clusters of MRI findings from people with LBP and that those clusters can be grouped into degenerative pathways that are biologically plausible. If these clusters of MRI findings are reproducible in other datasets of similar patients, they may form a stable platform to investigate the relationship between degenerative pathways and clinically important characteristics such as pain and activity limitation
The Estimation of the Effective Centre of Mass Energy in q-qbar-gamma Events from DELPHI
The photon radiation in the initial state lowers the energy available for the
ee collisions; this effect is particularly important at LEP2 energies
(above the mass of the Z boson). Being aligned to the beam direction, such
initial state radiation is mostly undetected. This article describes the
procedure used by the DELPHI experiment at LEP to estimate the effective
centre-of-mass energy in hadronic events collected at energies above the Z
peak. Typical resolutions ranging from 2 to 3 GeV on the effective
center-of-mass energy are achieved, depending on the event topology.Comment: 12 pages, 6 figure
The association of time since spousal loss and depression in widowhood: a systematic review and meta-analysis
\ua9 2019, The Author(s). Purpose: To conduct a systematic review and meta-analysis examining the association of the prevalence of depression and time since spousal loss in widowed people. Methods: The databases MEDLINE, Embase and PsycInfo were searched (May 2017) for papers reporting on time since spousal loss in widowed people and the prevalence of common mental disorders. A systematic review was conducted according to MOOSE guidelines. Random effects meta-analyses of the prevalence of depression were conducted by intervals of time since spousal loss. Results: The literature search identified 12,982 studies of which 22 were eligible for inclusion in the systematic review. Of these, 14 were furthermore eligible for inclusion in the meta-analysis. The summary estimates found in the meta-analysis for the prevalence of depression in the intervals of time since spousal loss were: ≤ 1 month: 38.2% (21.9–55.8%); > 1 month to 3 months: 25.0% (17.3–33.5%); > 3 months to 6 months: 23.1% (18.0–28.7%); > 6 months to 12 months: 19.4% (15.2–24.0%); > 12 months to 18 months: 11.1% (5.3–18.7%); > 18 months to 24 months: 15.2% (12.3–18.2%); > 24 months to 60 months: 10.5% (4.3–18.5%). Conclusion: Widowhood is associated with a high prevalence of depression and the study identifies a population group needing special attention in daily clinical practice. The prevalence is highest in the first month of widowhood, however, continues to be high at least 5 years into widowhood
Degenerative Pathways of Lumbar Motion Segments--A Comparison in Two Samples of Patients with Persistent Low Back Pain
Background: Magnetic resonance imaging (MRI) is used to identify spinal pathoanatomy in people with persistent low back pain. However, the clinical relevance of spinal degenerative MRI findings remains uncertain. Although multiple MRI findings are almost always present at the same time, research into the association with clinical outcomes (such as pain) has predominantly focused on individual MRI findings. This study aimed to: (i) investigate how multiple MRI lumbar spine findings cluster together within two different samples of patients with low back pain, (ii) classify these clusters into hypothetical pathways of degeneration based on scientific knowledge of disco-vertebral degeneration, and (iii) compare these clusters and degenerative pathways between samples. Methods: We performed a secondary cross-sectional analysis on two dissimilar MRI samples collected in a hospital department: (1) data from the spinal MRI reports of 4,162 low back pain patients and (2) data from an MRI research protocol of 631 low back pain patients. Latent Class Analysis was used in both samples to cluster MRI findings from lumbar motion segments. Using content analysis, each cluster was then categorised into hypothetical pathways of degeneration. Results: Six clusters of MRI findings were identified in each of the two samples. The content of the clusters in the two samples displayed some differences but had the same overall pattern of MRI findings. Although the hypothetical degenerative pathways identified in the two samples were not identical, the overall pattern of increasing degeneration within the pathways was the same. Conclusions: It was expected that different clusters could emerge from different samples, however, when organised into hypothetical pathways of degeneration, the overall pattern of increasing degeneration was similar and biologically plausible. This evidence of reproducibility suggests that Latent Class Analysis may provide a new approach to investigating the relationship between MRI findings and clinically important characteristics such as pain and activity limitation
Structure and Chemical Inhibition of the Ret Tyrosine Kinase Domain.
The RET proto-oncogene encodes a receptor tyrosine kinase for the glial cell line-derived neurotrophic factor family of ligands. Loss-of-function mutations in RET are implicated in Hirschsprung disease, whereas activating mutations in RET are found in human cancers, including familial medullar thyroid carcinoma and multiple endocrine neoplasias 2A and 2B. We report here the biochemical characterization of the human RET tyrosine kinase domain and the structure determination of the non-phosphorylated and phosphorylated forms. Both structures adopt the same active kinase conformation competent to bind ATP and substrate and have a pre-organized activation loop conformation that is independent of phosphorylation status. In agreement with the structural data, enzyme kinetic data show that autophosphorylation produces only a modest increase in activity. Longer forms of RET containing the juxtamembrane domain and C-terminal tail exhibited similar kinetic behavior, implying that there is no cis-inhibitory mechanism within the RET intracellular domain. Our results suggest the existence of alternative inhibitory mechanisms, possibly in trans, for the autoregulation of RET kinase activity. We also present the structures of the RET tyrosine kinase domain bound to two inhibitors, the pyrazolopyrimidine PP1 and the clinically relevant 4-anilinoquinazoline ZD6474. These structures explain why certain multiple endocrine neoplasia 2-associated RET mutants found in patients are resistant to inhibition and form the basis for design of more effective inhibitors
Ear-EEG detects ictal and interictal abnormalities in focal and generalized epilepsy:A comparison with scalp EEG monitoring
The morphology of the ejecta in Supernova 1987A: a study over time and wavelength
We present a study of the morphology of the ejecta in Supernova 1987A based
on images and spectra from the HST as well as integral field spectroscopy from
VLT/SINFONI. The HST observations were obtained between 1994 - 2011 and
primarily probe the outer hydrogen-rich zones of the ejecta. The SINFONI
observations were obtained in 2005 and 2011 and instead probe the [Si I]/[Fe
II] emission from the inner regions. We find a strong temporal evolution of the
morphology in the HST images, from a roughly elliptical shape before ~5,000
days, to a more irregular, edge-brightened morphology thereafter. This
transition is a natural consequence of the change in the dominant energy source
powering the ejecta, from radioactive decay before ~5,000 days to X-ray input
from the circumstellar interaction thereafter. The [Si I]/[Fe II] images
display a more uniform morphology, which may be due to a remaining significant
contribution from radioactivity in the inner ejecta and the higher abundance of
these elements in the core. Both the H-alpha and the [Si I]/[Fe II] line
profiles show that the ejecta are distributed fairly close to the plane of the
inner circumstellar ring, which is assumed to define the rotational axis of the
progenitor. The H-alpha emission extends to higher velocities than [Si I]/[Fe
II] as expected. There is no clear symmetry axis for all the emission and we
are unable to model the ejecta distribution with a simple ellipsoid model with
a uniform distribution of dust. Instead, we find that the emission is
concentrated to clumps and that the emission is distributed somewhat closer to
the ring in the north than in the south. This north-south asymmetry may be
partially explained by dust absorption. We compare our results with explosion
models and find some qualitative agreement, but note that the observations show
a higher degree of large-scale asymmetry.Comment: Accepted for publication in Ap
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