3,836 research outputs found
Emissionen organischer Verbindungen aus Baumaterialien
Recently, an internationally harmonized method for the characterization of emissions of organic compounds from building materials in test chambers has been developed and tested at the EMPA. Selected results from two projects indicate clearly, that the emissions not only depend on the
building material but are also strongly influenced by the mode of application. It is shown that some emissions caused by wall paints are influenced by the structure and material of the wall on which they are applied. Emissions from glues depend very strongly on structure and thickness of the
glued materials
Phase transition in a static granular system
We find that a column of glass beads exhibits a well-defined transition
between two phases that differ in their resistance to shear. Pulses of
fluidization are used to prepare static states with well-defined particle
volume fractions in the range 0.57-0.63. The resistance to shear is
determined by slowly inserting a rod into the column of beads. The transition
occurs at for a range of speeds of the rod.Comment: 4 pages, 4 figures. The paper is significantly extended, including
new dat
The sober rave project: investigating the acceptability and personal experiences of alcohol-free dance events
Our research is an innovative, European-wide collaborative investigation into the benefits of alcohol-free events, otherwise known as ‘sober raves’. Much of the existing behaviour work which focuses on preventing and regulating maladaptive alcohol misuse suggests individuals act rationally in choosing to consume alcohol. However, intentions and other cognitive mediators often fail to map onto actual behaviour and do not explain why individuals continue to carry out risky health-risk behaviours, despite being aware of the associated risks. Substance use is also often driven by the pursuit of pleasure, rather than by the avoidance of harms. For example, many young people get social pleasures from drinking alcohol, but due to limited alcohol-free socialising opportunities non-drinkers can feel stigmatised. Our research is focusing on the perceived acceptability, attitudes and perceptions of a range of alcohol-free events for young people across Europe. Following the first stage of this research project, we hope to explore how these types of events could be used as a means of reducing alcohol consumption in young people
Treatment exhaustion of highly active antiretroviral therapy (HAART) among individuals infected with HIV in the United Kingdon: multicentre cohort study
Objectives:
To investigate whether there is evidence that an increasing proportion of HIV infected patients is starting to experience increases in viral load and decreases in CD4 cell count that are consistent with exhaustion of available treatment options.
Design:
Multicentre cohort study.
Setting:
Six large HIV treatment centres in southeast England.
Participants:
All individuals seen for care between 1 January 1996 and 31 December 2002.
Main outcome measures:
Exposure to individual antiretroviral drugs and drug classes, CD4 count, plasma HIV RNA burden.
Results:
Information is available on 16 593 individuals (13 378 (80.6%) male patients, 10 340 (62.3%) infected via homosexual or bisexual sex, 4426 (26.7%) infected via heterosexual sex, median age 34 years). Overall, 10 207 of the 16 593 patients (61.5%) have been exposed to any antiretroviral therapy. This proportion increased from 41.2% of patients under follow up at the end of 1996 to 71.3% of those under follow up in 2002. The median CD4 count and HIV RNA burden of patients under follow up in each year changed from 270 cells/mm3 and 4.34 log10 copies/ml in 1996 to 408 cells/mm3 and 1.89 log10 copies/ml, respectively, in 2002. By 2002, 3060 (38%) of patients who had ever been treated with antiretroviral therapy had experienced all three main classes. Of these, around one quarter had evidence of “viral load failure” with all these three classes. Patients with three class failure were more likely to have an HIV RNA burden > 2.7 log10 copies/ml and a CD4 count < 200 cells/mm3.
Conclusions:
The proportion of individuals with HIV infection in the United Kingdom who have been treated has increased gradually over time. A substantial proportion of these patients seem to be in danger of exhausting their options for antiretroviral treatment. New drugs with low toxicity, which are not associated with cross resistance to existing drugs, are urgently needed for such patients
Automated fragment identification for electron ionisation mass spectrometry: application to atmospheric measurements of halocarbons
Non-target screening consists in searching a sample for all present
substances, suspected or unknown, with very little prior knowledge about the
sample. This approach has been introduced more than a decade ago in the field
of water analysis, together with dedicated compound identification tools, but
is still very scarce for indoor and atmospheric trace gas measurements, despite
the clear need for a better understanding of the atmospheric trace gas
composition.For a systematic detection of emerging trace gases in the
atmosphere, a new and powerful analytical method is gas chromatography (GC) of
preconcentrated samples, followed by electron ionisation, high resolution mass
spectrometry (EI-HRMS). In this work, we present data analysis tools to enable
automated fragment formula annotation for unknown compounds measured by
GC-EI-HRMS. Based on co-eluting mass/charge fragments, we developed an
innovative data analysis method to reliably reconstruct the chemical formulae
of the fragments, using efficient combinatorics and graph theory. The method
does not require the presence of the molecular ion, which is absent in ~40% of
EI spectra. Our method has been trained and validated on \textgreater50
halocarbons and hydrocarbons, with 3 to 20 atoms and molar masses of 30 to 330
g mol-1, measured with a mass resolution of approx.~3500. For 90% of the
compounds, more than 90% of the annotated fragment formulae are correct. Cases
of wrong identification can be attributed to the scarcity of detected fragments
per compound or the lack of isotopic constraint (no minor isotopocule
detected).Our method enables to reconstruct most probable chemical formulae
independently from spectral databases. Therefore, it demonstrates the
suitability of EI-HRMS data for non-target analysis and paves the way for the
identification of substances for which no EI mass spectrum is registered in
databases. We illustrate the performances of our method for atmospheric trace
gases and suggest that it may be well suited for many other types of samples.
The L-GPL licenced Python code is released under the name ALPINAC for
ALgorithmic Process for Identification of Non-targeted Atmospheric Compounds.Comment: Journal of Cheminformatics, Chemistry Central Ltd. and BioMed
Central, 202
NFIRAOS First Facility AO System for the Thirty Meter Telescope
NFIRAOS, the Thirty Meter Telescope's first adaptive optics system is an
order 60x60 Multi-Conjugate AO system with two deformable mirrors. Although
most observing will use 6 laser guide stars, it also has an NGS-only mode.
Uniquely, NFIRAOS is cooled to -30 C to reduce thermal background. NFIRAOS
delivers a 2-arcminute beam to three client instruments, and relies on up to
three IR WFSs in each instrument. We present recent work including: robust
automated acquisition on these IR WFSs; trade-off studies for a common-size of
deformable mirror; real-time computing architectures; simplified designs for
high-order NGS-mode wavefront sensing; modest upgrade concepts for
high-contrast imaging.Comment: ..submitted to SPIE 9148 Astronomical Telescopes and Instrumentation
- Adaptive Optics Systems IV (2014
Improving Motor Activity Assessment in Depression: Which Sensor Placement, Analytic Strategy and Diurnal Time Frame Are Most Powerful in Distinguishing Patients from Controls and Monitoring Treatment Effects
Background
Abnormalities in motor activity represent a central feature in major depressive disorder. However, measurement issues are poorly understood, limiting the use of objective measurement of motor activity for diagnostics and treatment monitoring.
Methods
To improve measurement issues, especially sensor placement, analytic strategies and diurnal effects, we assessed motor activity in depressed patients at the beginning (MD; n=27) and after anti-depressive treatment (MD-post; n=18) as well as in healthy controls (HC; n=16) using wrist- and chest-worn accelerometers. We performed multiple analyses regarding sensor placements, extracted features, diurnal variation, motion patterns and posture to clarify which parameters are most powerful in distinguishing patients from controls and monitoring treatment effects.
Results
Whereas most feature-placement combinations revealed significant differences between groups, acceleration (wrist) distinguished MD from HC (d=1.39) best. Frequency (vertical axis chest) additionally differentiated groups in a logistic regression model (R2=0.54). Accordingly, both amplitude (d=1.16) and frequency (d=1.04) showed alterations, indicating reduced and decelerated motor activity. Differences between MD and HC in gestures (d=0.97) and walking (d=1.53) were found by data analysis from the wrist sensor. Comparison of motor activity at the beginning and after MD-treatment largely confirms our findings.
Limitations
Sample size was small, but sufficient for the given effect sizes. Comparison of depressed in-patients with non-hospitalized controls might have limited motor activity differences between groups.
Conclusions
Measurement of wrist-acceleration can be recommended as a basic technique to capture motor activity in depressed patients as it records whole body movement and gestures. Detailed analyses showed differences in amplitude and frequency denoting that depressed patients walked less and slower
Factorization and the Soft Overlap Contribution to Heavy-to-Light Form Factors
Using the formalism of soft-collinear effective theory, a complete separation
of short- and long-distance contributions to heavy-to-light transition form
factors at large recoil is performed. The universal functions
parameterizing the ``soft overlap'' contribution to the form factors are
defined in terms of matrix elements in the effective theory. Endpoint
configurations corresponding to kinematic situations where one of the valence
partons in the external mesons carries very small momentum are accounted for in
terms of operators involving soft-collinear messenger fields. They contribute
at leading order in and spoil factorization. An analysis
of operator mixing and renormalization-group evolution in the effective theory
reveals that the intermediate scale is without significance
to the soft functions , and that the soft overlap contribution does
not receive a significant perturbative (Sudakov) suppression.Comment: 30 pages, 6 figures. Erratum adde
Soft-Collinear Messengers: A New Mode in Soft-Collinear Effective Theory
It is argued that soft-collinear effective theory for processes involving
both soft and collinear partons, such as exclusive B-meson decays, should
include a new mode in addition to soft and collinear fields. These
"soft-collinear messengers" can interact with both soft and collinear particles
without taking them far off-shell. They thus can communicate between the soft
and collinear sectors of the theory. The relevance of the new mode is
demonstrated with an explicit example, and the formalism incorporating the
corresponding quark and gluon fields into the effective Lagrangian is
developed.Comment: 22 pages, 5 figures. Extended Section 6, clarifying the relevance of
different types of soft-collinear interaction
Regulation of Human γδ T Cells by BTN3A1 Protein Stability and ATP-Binding Cassette Transporters
Activation of human Vγ9/Vδ2 T cells by ‘phosphoantigens’ (pAg), the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP) and the endogenous isoprenoid intermediate isopentenyl pyrophosphate (IPP), requires expression of butyrophilin BTN3A molecules by presenting cells. However, the precise mechanism of activation of Vγ9/Vδ2 T cells by BTN3A molecules remains elusive. It is not clear what conformation of the three BTN3A isoforms transmits activation signals nor how externally delivered pAg accesses the cytosolic B30.2 domain of BTN3A1. To approach this problem we studied two HLA haplo-identical HeLa cell lines, termed HeLa-L and HeLa-M, which showed marked differences in pAg-dependent stimulation of Vγ9/Vδ2 T cells. Levels of IFN-γ secretion by Vγ9/Vδ2 T cells were profoundly increased by pAg loading, or by binding of the pan-BTN3A specific agonist antibody CD277 20.1, in HeLa-M compared to HeLa-L cells. IL-2 production from a murine hybridoma T cell line expressing human Vγ9/Vδ2 TCR transgenes confirmed that the differential responsiveness to HeLa-L and HeLa-M was TCR dependent. By tissue typing, both HeLa lines were shown to be genetically identical and full-length transcripts of the three BTN3A isoforms were detected in equal abundance with no sequence variation. Expression of BTN3A and interacting molecules such as periplakin or RhoB did not account for the functional variation between HeLa-L and HeLa-M cells, although evidence implicates a mechanism controlling BTN3A protein stability and trafficking. Plasma membrane profiling was used to identify proteins upregulated in HMB-PP treated HeLa-M. ABCG2, a member of the ABC transporter family was the most significant candidate, which crucially showed reduced expression in HeLa-L. Expression of a subset of ABC transporters, including ABCA1 and ABCG1, correlated with efficiency of T cell activation by cytokine secretion, although direct evidence of a functional role was not obtained by knockdown experiments. Our findings indicate a link between members of the ABC protein superfamily and the BTN3A-dependent activation of γδ T cells by endogenous and exogenous pAg
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