404 research outputs found
Mismatch between the 1997/1998 influenza vaccine and the major epidemic A (H3N2) virus strain as the cause of an inadequate vaccine-induced antibody response to this strain in the elderly.
The success of influenza vaccination depends largely on the antigenic match between the influenza vaccine strains and the virus strains actually circulating during the season. In the past, this match has proved to be satisfactory in most seasons. In the 1997/1998 season, however, hemagglutination inhibition (HI) assays with ferret antisera indicated a considerable mismatch between the H3N2 vaccine component and the most prevalent epidemic influenza A(H3N2) virus. The results from antigenic analyses using pre- and postvaccination serum samples from volunteers of various ages, including residents of nursing homes who were more than 60 years of age, were in good agreement with the results obtained with ferret antisera. Homologous serum antibody responses to the H3N2 vaccine component as well as the cross-reactivity of the induced antibodies to the epidemic H3N2 strain, declined with increasing age of the vaccinees. As a consequence of these two effects, 84% of the vaccinees over 75 years of age did not develop HI antibody titers >/= 40 against the major H3N2 virus variant of 1997/1998, suggesting that they were not protected against infection with this virus variant. These findings support the current policy of the World Health Organization (WHO), which is to base worldwide influenza virus surveillance on results predominantly obtained by antigenic analyses of influenza virus isolates with ferret antisera in HI tests. If an antigenic mismatch is observed, the protective efficacy of the vaccine, especially for the elderly, may be insufficient. The observations also support the current policy to include the elderly in serologic efficacy trials
Characterisation of novel thin n-in-p planar pixel modules for the ATLAS Inner Tracker upgrade
In view of the high luminosity phase of the LHC (HL-LHC) to start operation
around 2026, a major upgrade of the tracker system for the ATLAS experiment is
in preparation. The expected neutron equivalent fluence of up to 2.4 * 1e16 1
MeV neq./cm2 at the innermost layer of the pixel detector poses the most severe
challenge. Thanks to their low material budget and high charge collection
efficiency after irradiation, modules made of thin planar pixel sensors are
promising candidates to instrument these layers. To optimise the sensor layout
for the decreased pixel cell size of 50 * 50 {\mu}m2, TCAD device simulations
are being performed to investigate the charge collection efficiency before and
after irradiation. In addition, sensors of 100-150 {\mu}m thickness,
interconnected to FE-I4 read-out chips featuring the previous generation pixel
cell size of 50 * 250 {\mu}m2, are characterised with testbeams at the CERN-SPS
and DESY facilities. The performance of sensors with various designs,
irradiated up to a fluence of 1 * 1e16 neq./cm2, is compared in terms of charge
collection and hit efficiency. A replacement of the two innermost pixel layers
is foreseen during the lifetime of HL-LHC. The replacement will require several
months of intervention, during which the remaining detector modules cannot be
cooled. They are kept at room temperature, thus inducing an annealing. The
performance of irradiated modules will be investigated with testbeam campaigns
and the method of accelerated annealing at higher temperatures.Comment: 11 pages, 10 figures, proceedings of the PSD Conference 201
Analysis of antigenic relationships among influenza virus strains using a taxonomic cluster procedure. Comparison of three kinds of antibody preparations.
Hemagglutination inhibiting (HI) monoclonal antibody preparations (MA) were raised against six influenza A (H3N2) strains from the period 1977-1982. Twenty-three hybridomas were selected and titrated in HI assays against these strains and against 18 influenza A (H3N2) viruses isolated in The Netherlands during the seasons 1981-1982 and 1982-1983. Similar HI tests were performed with conventional post-infection ferret antisera and with ferret antisera adsorbed with heterologous strains of influenza A (H3N2) virus. The resulting serological data were subjected to a computerized taxonomic cluster procedure based on the Euclidean distance between viruses. With respect to the degree of separation between clusters the unadsorbed ferret antisera were inferior to the adsorbed antisera whereas the MA were superior to both. Our results demonstrate that computer programs based on numerical taxonomy can be helpful in processing large numbers of serological data and that MA are indispensable in epidemiological and diagnostic influenza studies
Checking Properties Described by State Machines: On Synergy of Instrumentation, Slicing, and Symbolic Execution
We introduce a novel technique for checking properties described by finite state machines. The technique is based on a synergy of three well-known methods: instrumentation, program slicing, and symbolic execution. More precisely, we instrument a given program with a code that tracks runs of state machines representing various properties. Next we slice the program to reduce its size without affecting runs of state machines. And then we symbolically execute the sliced program to find real violations of the checked properties, i.e. real bugs. Depending on the kind of symbolic execution, the technique can be applied as a stand-alone bug finding technique, or to weed out some false positives from an output of another bug-finding tool. We provide several examples demonstrating the practical applicability of our technique.Představujeme novou techniku pro ověřování vlastností popsaných konečně-stavovými stroji. Tato technika je založena na synergii tří známých metod: instrumentace, prořezání programu a symbolické vykonání. Přesněji, instrumentujeme daný program kódem, který sleduje běh stavových strojů představujících různé vlastnosti. Dále program prořežeme, abychom zmenšili jeho velikost při zachování běhů stavových strojů. Nakonec prořezaný program symbolicky vykonáme, abychom našli skutečné porušení ověřovaných vlastností, t.j. skutečné chyby. Podle použitého druhu symbolického vykonání může být tato technika použita jako samostatná metoda pro detekci chyb nebo k vytřídění některých falešných hlášení z výstupu jiných nástrojů pro detekci chyb. Poskytujeme několik příkladů, které dokumentují praktickou použitelnost naší techniky
Prevalence and clinical symptoms of human metapneumovirus infection in hospitalized patients
During a 17-month period, we performed retrospective analyses of the prevalence of and clinical symptoms associated with human metapneumovirus (hMPV) infection, among patients in a university hospital in The Netherlands. All available nasal-aspirate, throat-swab, sputum, and bronchoalveolar-lavage samples (N=1515) were tested for hMPV RNA by reverse-transcriptase polymerase chain reaction. hMPV RNA was detected in 7% of samples from patients with respiratory tract illnesses (RTIs) and was the second-most-detected viral pathogen in these patients during the last 2 winter seasons. hMPV was detected primarily in very young children and in immunocompromised individuals. In young children, clinical symptoms associated with hMPV infection were similar to those associated with human respiratory syncytial virus (hRSV) infection, but dyspnea, feeding difficulties, and hypoxemia were reported more frequently in hRSV-infected children. Treatment with antibiotics and corticosteroids was reported more frequently in hMPV-infected children. From these data, we conclude that hMPV is an important pathogen associated with RTI
Night optimised care technology for users needing assisted lifestyles
There is growing interest in the development of ambient assisted living services to increase the quality of life of the increasing proportion of the older population. We report on the Night Optimised Care Technology for UseRs Needing Assisted Lifestyles project, which provides specialised night time support to people at early stages of dementia. This article explains the technical infrastructure, the intelligent software behind the decision-making driving the system, the software development process followed, the interfaces used to interact with the user, and the findings and lessons of our user-centred approach
Diagnosing and measuring incompatibilities between pairs of services
International audienceThis text presents a tool, from its design to its implementation, which detects all behavioural incompatibilities between two service interfaces. Unlike prior work, the proposed solution does not simply check whether two services are incompatible or not, it rather provides detailed diagnosis, including the incompatibilities and for each one the location in the service interfaces where these incompatibilities occur. A measure of similarity between interfaces which considers outputs from the detection algorithm is proposed too. A visual report of the comparison analysis is also provided which pinpoints a set of incompatibilities that cause a behavioural interface not to simulate another one
Production of Medical Radioisotopes with High Specific Activity in Photonuclear Reactions with Beams of High Intensity and Large Brilliance
We study the production of radioisotopes for nuclear medicine in
photonuclear reactions or ()
photoexcitation reactions with high flux [()/s], small
diameter m and small band width () beams produced by Compton back-scattering of laser
light from relativistic brilliant electron beams. We compare them to (ion,np) reactions with (ion=p,d,) from particle accelerators like
cyclotrons and (n,) or (n,f) reactions from nuclear reactors. For
photonuclear reactions with a narrow beam the energy deposition in the
target can be managed by using a stack of thin target foils or wires, hence
avoiding direct stopping of the Compton and pair electrons (positrons).
isomer production via specially selected cascades
allows to produce high specific activity in multiple excitations, where no
back-pumping of the isomer to the ground state occurs. We discuss in detail
many specific radioisotopes for diagnostics and therapy applications.
Photonuclear reactions with beams allow to produce certain
radioisotopes, e.g. Sc, Ti, Cu, Pd, Sn,
Er, Pt or Ac, with higher specific activity and/or
more economically than with classical methods. This will open the way for
completely new clinical applications of radioisotopes. For example Pt
could be used to verify the patient's response to chemotherapy with platinum
compounds before a complete treatment is performed. Also innovative isotopes
like Sc, Cu and Ac could be produced for the first time
in sufficient quantities for large-scale application in targeted radionuclide
therapy.Comment: submitted to Appl. Phys.
The CAT Imaging Telescope for Very-High-Energy Gamma-Ray Astronomy
The CAT (Cherenkov Array at Themis) imaging telescope, equipped with a
very-high-definition camera (546 fast phototubes with 0.12 degrees spacing
surrounded by 54 larger tubes in two guard rings) started operation in Autumn
1996 on the site of the former solar plant Themis (France). Using the
atmospheric Cherenkov technique, it detects and identifies very high energy
gamma-rays in the range 250 GeV to a few tens of TeV. The instrument, which has
detected three sources (Crab nebula, Mrk 421 and Mrk 501), is described in
detail.Comment: 24 pages, 15 figures. submitted to Elsevier Preprin
A Phenomenological Analysis of Gluon Mass Effects in Inclusive Radiative Decays of the and $\Upsilon
The shapes of the inclusive photon spectra in the processes \Jp \to \gamma
X and \Up \to \gamma X have been analysed using all available experimental
data.
Relativistic, higher order QCD and gluon mass corrections were taken into
account in the fitted functions. Only on including the gluon mass corrections,
were consistent and acceptable fits obtained. Values of
GeV and GeV were found for the
effective gluon masses (corresponding to Born level diagrams) for the \Jp and
\Up respectively. The width ratios \Gamma(V \to {\rm hadrons})/\Gamma(V \to
\gamma+ {\rm hadrons}) V=\Jp, \Up were used to determine and . Values consistent with the current world
average were obtained only when gluon mass correction factors,
calculated using the fitted values of the effective gluon mass, were applied. A
gluon mass GeV, as suggested with these results, is consistent with
previous analytical theoretical calculations and independent phenomenological
estimates, as well as with a recent, more accurate, lattice calculation of the
gluon propagator in the infra-red region.Comment: 50 pages, 11 figures, 15 table
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