457 research outputs found
Discriminating among Earth composition models using geo-antineutrinos
It has been estimated that the entire Earth generates heat corresponding to
about 40 TW (equivalent to 10,000 nuclear power plants) which is considered to
originate mainly from the radioactive decay of elements like U, Th and K,
deposited in the crust and mantle of the Earth. Radioactivity of these elements
produce not only heat but also antineutrinos (called geo-antineutrinos) which
can be observed by terrestrial detectors. We investigate the possibility of
discriminating among Earth composition models predicting different total
radiogenic heat generation, by observing such geo-antineutrinos at Kamioka and
Gran Sasso, assuming KamLAND and Borexino (type) detectors, respectively, at
these places. By simulating the future geo-antineutrino data as well as reactor
antineutrino background contributions, we try to establish to which extent we
can discriminate among Earth composition models for given exposures (in units
of kt yr) at these two sites on our planet. We use also information on
neutrino mixing parameters coming from solar neutrino data as well as KamLAND
reactor antineutrino data, in order to estimate the number of geo-antineutrino
induced events.Comment: 24 pages, 10 figures, final version to appear in JHE
Harmonisation of short-term in vitro culture for the expansion of antigen-specific CD8(+) T cells with detection by ELISPOT and HLA-multimer staining.
Ex vivo ELISPOT and multimer staining are well-established tests for the assessment of antigen-specific T cells. Many laboratories are now using a period of in vitro stimulation (IVS) to enhance detection. Here, we report the findings of a multi-centre panel organised by the Association for Cancer Immunotherapy Immunoguiding Program to investigate the impact of IVS protocols on the detection of antigen-specific T cells of varying ex vivo frequency. Five centres performed ELISPOT and multimer staining on centrally prepared PBMCs from 3 donors, both ex vivo and following IVS. A harmonised IVS protocol was designed based on the best-performing protocol(s), which was then evaluated in a second phase on 2 donors by 6 centres. All centres were able to reliably detect antigen-specific T cells of high/intermediate frequency both ex vivo (Phase I) and post-IVS (Phase I and II). The highest frequencies of antigen-specific T cells ex vivo were mirrored in the frequencies following IVS and in the detection rates. However, antigen-specific T cells of a low/undetectable frequency ex vivo were not reproducibly detected post-IVS. Harmonisation of the IVS protocol reduced the inter-laboratory variation observed for ELISPOT and multimer analyses by approximately 20 %. We further demonstrate that results from ELISPOT and multimer staining correlated after (P < 0.0001 and R (2) = 0.5113), but not before IVS. In summary, IVS was shown to be a reproducible method that benefitted from method harmonisation
The Dutch health insurance reform: switching between insurers, a comparison between the general population and the chronically ill and disabled
Background: On 1 January 2006 a number of far-reaching changes in the Dutch health insurance
system came into effect. In the new system of managed competition consumer mobility plays an
important role. Consumers are free to change their insurer and insurance plan every year. The idea
is that consumers who are not satisfied with the premium or quality of care provided will opt for
a different insurer. This would force insurers to strive for good prices and quality of care.
Internationally, the Dutch changes are under the attention of both policy makers and researchers.
Questions answered in this article relate to switching behaviour, reasons for switching, and
differences between population categories.
Methods: Postal questionnaires were sent to 1516 members of the Dutch Health Care Consumer
Panel and to 3757 members of the National Panel of the Chronically ill and Disabled (NPCD) in
April 2006. The questionnaire was returned by 1198 members of the Consumer Panel (response
79%) and by 3211 members of the NPCD (response 86%). Among other things, questions were
asked about choices for a health insurer and insurance plan and the reasons for this choice.
Results: Young and healthy people switch insurer more often than elderly or people in bad health.
The chronically ill and disabled do not switch less often than the general population when both
populations are comparable on age, sex and education.
For the general population, premium is more important than content, while the chronically ill and
disabled value content of the insurance package as well. However, quality of care is not important
for either group as a reason for switching.
Conclusion: There is increased mobility in the new system for both the general population and
the chronically ill and disabled. This however is not based on quality of care. If reasons for switching
are unrelated to the quality of care, it is hard to believe that switching influences the quality of care.
As yet there are no signs of barriers to switch insurer for the chronically ill and disabled. This
however could change in the future and it is therefore important to monitor changes.
Cerebrospinal Fluid Concentration of Brain-Derived Neurotrophic Factor and Cognitive Function in Non-Demented Subjects
Brain-derived neurotrophic factor (BDNF) is an activity-dependent secreted protein that is critical to organization of neuronal networks and synaptic plasticity, especially in the hippocampus. We tested hypothesis that reduced CSF BDNF is associated with age-related cognitive decline.CSF concentration of BDNF, Abeta(42) and total tau were measured in 128 cognitively normal adults (Normals), 21 patients with Alzheimer's disease (AD), and nine patients with Mild Cognitive Impairment. Apolipoprotein E and BDNF SNP rs6265 genotype were determined. Neuropsychological tests were performed at baseline for all subjects and at follow-up visits in 50 Normals. CSF BDNF level was lower in AD patients compared to age-matched Normals (p = 0.02). CSF BDNF concentration decreased with age among Normals and was higher in women than men (both p<0.001). After adjusting for age, gender, education, CSF Abeta(42) and total tau, and APOE and BDNF genotypes, lower CSF BDNF concentration was associated poorer immediate and delayed recall at baseline (both p<0.05) and in follow up of approximately 3 years duration (both p<0.01).Reduced CSF BDNF was associated with age-related cognitive decline, suggesting a potential mechanism that may contribute in part to cognitive decline in older individuals
Harmonisation of short-term in vitro culture for the expansion of antigen-specific CD8+ T cells with detection by ELISPOT and HLA-multimer staining
Ex vivo ELISPOT and multimer staining are well-established tests for the assessment of antigen-specific T cells. Many laboratories are now using a period of in vitro stimulation (IVS) to enhance detection. Here, we report the findings of a multi-centre panel organised by the Association for Cancer Immunotherapy Immunoguiding Program to investigate the impact of IVS protocols on the detection of antigen-specific T cells of varying ex vivo frequency. Five centres performed ELISPOT and multimer staining on centrally prepared PBMCs from 3 donors, both ex vivo and following IVS. A harmonised IVS protocol was designed based on the best-performing protocol(s), which was then evaluated in a second phase on 2 donors by 6 centres. All centres were able to reliably detect antigen-specific T cells of high/intermediate frequency both ex vivo (Phase I) and post-IVS (Phase I and II). The highest frequencies of antigen-specific T cells ex vivo were mirrored in the frequencies following IVS and in the detection rates. However, antigen-specific T cells of a low/undetectable frequency ex vivo were not reproducibly detected post-IVS. Harmonisation of the IVS protocol reduced the inter-laboratory variation observed for ELISPOT and multimer analyses by approximately 20 %. We further demonstrate that results from ELISPOT and multimer staining correlated after (P < 0.0001 and R(2) = 0.5113), but not before IVS. In summary, IVS was shown to be a reproducible method that benefitted from method harmonisation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00262-014-1593-0) contains supplementary material, which is available to authorized users
Torsion-balance tests of the weak equivalence principle
We briefly summarize motivations for testing the weak equivalence principle
and then review recent torsion-balance results that compare the differential
accelerations of beryllium-aluminum and beryllium-titanium test body pairs with
precisions at the part in level. We discuss some implications of
these results for the gravitational properties of antimatter and dark matter,
and speculate about the prospects for further improvements in experimental
sensitivity.Comment: 17 pages, 9 figures (in press Classical Quantum Gravity 2012
Resting-State Functional Connectivity Disruption as a Pathological Biomarker in Autosomal Dominant Alzheimer Disease
AIM: Identify a global resting state functional connectivity (gFC) signature in mutation carriers (MC) from the Dominantly Inherited Alzheimer Network (DIAN). Assess the gFC with regards to amyloid (A), tau (T), and neurodegeneration (N) biomarkers and estimated years to symptom onset (EYO). INTRODUCTION: Cross-sectional measures were assessed in MC (n=171) and mutation non-carriers (NC) (n=70) participants. A FC matrix that encompassed multiple resting state networks (RSNs) was computed for each participant. METHODS: A gFC was compiled as a single index indicating functional connectivity strength. Global FC signature was modeled as a non-linear function of EYO. gFC was linearly associated with other biomarkers used for assessing the AT(N) framework including: cerebrospinal fluid (CSF), positron emission tomography (PET) molecular biomarkers, and structural magnetic resonance imaging. RESULTS: The gFC was reduced in MC compared to NC participants. When MC participants were differentiated by clinical dementia rating (CDR), the gFC was significantly decreased in MC CDR > 0 (demented) compared to either MC CDR 0 (cognitively normal) or NC participants. The gFC varied non-linearly with EYO and initially decreased at EYO = -24 years, followed by a stable period followed by a further decline near EYO =0 years. Irrespective of EYO, a lower gFC associated with values of amyloid PET, CSF Aβ1-42, CSF p-tau, CSF t-tau, FDG and hippocampal volume. CONCLUSIONS: The gFC correlated with biomarkers used for defining the AT(N) framework. A biphasic change in the gFC suggested early changes associated with CSF amyloid and later changes associated with hippocampal volume
Providing baseline data for conservation–Heart rate monitoring in captive scimitar-horned oryx
Heart rate biologging has been successfully used to study wildlife responses to natural and human-caused stressors (e.g., hunting, landscape of fear). Although rarely deployed to inform conservation, heart rate biologging may be particularly valuable for assessing success in wildlife reintroductions. We conducted a case study for testing and validating the use of subcutaneous heart rate monitors in eight captive scimitar-horned oryx (Oryx dammah), a once-extinct species that is currently being restored to the wild. We evaluated biologger safety and accuracy while collecting long-term baseline data and assessing factors explaining variation in heart rate. None of the biologgers were rejected after implantation, with successful data capture for 16–21 months. Heart rate detection accuracy was high (83%–99%) for six of the individuals with left lateral placement of the biologgers. We excluded data from two individuals with a right lateral placement because accuracies were below 60%. Average heart rate for the six scimitar-horned oryx was 60.3 ± 12.7 bpm, and varied by about 12 bpm between individuals, with a minimum of 31 bpm and a maximum of 188 bpm across individuals. Scimitar-horned oryx displayed distinct circadian rhythms in heart rate and activity. Heart rate and activity were low early in the morning and peaked near dusk. Circadian rhythm in heart rate and activity were relatively unchanged across season, but hourly averages for heart rate and activity were higher in spring and summer, respectively. Variation in hourly heart rate averages was best explained by a combination of activity, hour, astronomical season, ambient temperature, and an interaction term for hour and season. Increases in activity appeared to result in the largest changes in heart rate. We concluded that biologgers are safe and accurate and can be deployed in free-ranging and reintroduced scimitar-horned oryx. In addition to current monitoring practices of reintroduced scimitar-horned oryx, the resulting biologging data could significantly aid in 1) evaluating care and management action prior to release, 2) characterizing different animal personalities and how these might affect reintroduction outcomes for individual animals, and 3) identifying stressors after release to determine their timing, duration, and impact on released animals. Heart rate monitoring in released scimitar-horned oryx may also aid in advancing our knowledge about how desert ungulates adapt to extreme environmental variation in their habitats (e.g., heat, drought)
Hippocampal and Hippocampal-Subfield Volumes From Early-Onset Major Depression and Bipolar Disorder to Cognitive Decline
Background: The hippocampus and its subfields (HippSub) are reported to be diminished in patients with Alzheimer's disease (AD), bipolar disorder (BD), and major depressive disorder (MDD). We examined these groups vs healthy controls (HC) to reveal HippSub alterations between diseases.
Methods: We segmented 3T-MRI T2-weighted hippocampal images of 67 HC, 58 BD, and MDD patients from the AFFDIS study and 137 patients from the DELCODE study assessing cognitive decline, including subjective cognitive decline (SCD), amnestic mild cognitive impairment (aMCI), and AD, via Free Surfer 6.0 to compare volumes across groups.
Results: Groups differed significantly in several HippSub volumes, particularly between patients with AD and mood disorders. In comparison to HC, significant lower volumes appear in aMCI and AD groups in specific subfields. Smaller volumes in the left presubiculum are detected in aMCI and AD patients, differing from the BD group. A significant linear regression is seen between left hippocampus volume and duration since the first depressive episode.
Conclusions: HippSub volume alterations were observed in AD, but not in early-onset MDD and BD, reinforcing the notion of different neural mechanisms in hippocampal degeneration. Moreover, duration since the first depressive episode was a relevant factor explaining the lower left hippocampal volumes present in groups
Association between composite scores of domain-specific cognitive functions and regional patterns of atrophy and functional connectivity in the Alzheimer's disease spectrum
Background: Cognitive decline has been found to be associated with gray matter atrophy and disruption of
functional neural networks in Alzheimer’s disease (AD) in structural and functional imaging (fMRI) studies. Most
previous studies have used single test scores of cognitive performance among monocentric cohorts. However,
cognitive domain composite scores could be more reliable than single test scores due to the reduction of measurement error. Adopting a multicentric resting state fMRI (rs-fMRI) and cognitive domain approach, we provide
a comprehensive description of the structural and functional correlates of the key cognitive domains of AD.
Method: We analyzed MRI, rs-fMRI and cognitive domain score data of 490 participants from an interim baseline
release of the multicenter DELCODE study cohort, including 54 people with AD, 86 with Mild Cognitive
Impairment (MCI), 175 with Subjective Cognitive Decline (SCD), and 175 Healthy Controls (HC) in the ADspectrum. Resulting cognitive domain composite scores (executive, visuo-spatial, memory, working memory
and language) from the DELCODE neuropsychological battery (DELCODE-NP), were previously derived using
confirmatory factor analysis. Statistical analyses examined the differences between diagnostic groups, and the
association of composite scores with regional atrophy and network-specific functional connectivity among the
patient subgroup of SCD, MCI and AD.
Result: Cognitive performance, atrophy patterns and functional connectivity significantly differed between
diagnostic groups in the AD-spectrum. Regional gray matter atrophy was positively associated with visuospatial
and other cognitive impairments among the patient subgroup in the AD-spectrum. Except for the visual network,
patterns of network-specific resting-state functional connectivity were positively associated with distinct
cognitive impairments among the patient subgroup in the AD-spectrum.
Conclusion: Consistent associations between cognitive domain scores and both regional atrophy and networkspecific functional connectivity (except for the visual network), support the utility of a multicentric and
cognitive domain approach towards explicating the relationship between imaging markers and cognition in the
AD-spectrum
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