5,011 research outputs found
Optical doping and damage formation in AIN by Eu implantation
AlN films grown on sapphire were implanted with 300 keV Eu ions to fluences from 3×1014 to 1.4×1017 atoms/cm2 in two different geometries: “channeled” along the c-axis and “random” with a 10° angle between the ion beam and the surface normal. A detailed study of implantation damage accumulation is presented. Strong ion channeling effects are observed leading to significantly decreased damage levels for the channeled implantation within the entire fluence range. For random implantation, a buried amorphous layer is formed at the highest fluences. Red Eu-related photoluminescence at room temperature is observed in all samples with highest intensities for low damage samples (low fluence and channeled implantation) after annealing. Implantation damage, once formed, is shown to be stable up to very high temperatures.FCT - POCI/FIS/57550/2004FCT - PTDC/FIS/66262/2006FCT - PTDC/CTM/100756/200
Importance of immunogenicity testing for cost-effective management of psoriasis patients treated with adalimumab
INTRODUCTION:
Up to 30% of patients treated with anti-tumor necrosis factor drugs do not respond adequately, and up to 50% lose response over time. Immunogenicity is now known to be one of the main causes of this loss of response.
METHODS:
Serum levels of adalimumab and anti-drug antibodies (ADAs) were measured in 19 patients with psoriasis.
RESULTS:
Eighty-nine percent of the patients were responders (Psoriasis Area Severity Index (PASI) > 75) and 11% were partial responders (PASI 50-75). The serum levels of adalimumab were lower than the cutoff in both of the partial responders and the ADAs were high, whereas the other 17 patients had adalimumab levels above the cutoff and low ADA levels. Both partial responders were obese and none of them were taking methotrexate. Both patients switched to ustekinumab, and a PASI 90 response was observed after 16 weeks.
CONCLUSION:
Immunogenicity is a risk of biological drugs. In this work, the detection of low levels of adalimumab and high levels of ADAs using a sandwich ELISA correlated with loss of clinical response. Testing immunogenicity and the drug pharmacokinetics of biological drugs in psoriasis patients will probably be part of the daily management of these patients in the future.info:eu-repo/semantics/publishedVersio
Functionalizing self-assembled GaN quantum dot superlattices by Eu-implantation
Self-assembled GaN quantum dots (QDs) stacked in superlattices (SL) with AlN spacer layers were implanted with Europium ions to fluences of 1013, 1014, and 1015 cm−2. The damage level introduced in the QDs by the implantation stays well below that of thick GaN epilayers. For the lowest fluence, the structural properties remain unchanged after implantation and annealing while for higher fluences the implantation damage causes an expansion of the SL in the [0001] direction which increases with implantation fluence and is only partly reversed after thermal annealing at 1000 °C. Nevertheless, in all cases, the SL quality remains very good after implantation and annealing with Eu ions incorporated preferentially into near-substitutional cation sites. Eu3+ optical activation is achieved after annealing in all samples. In the sample implanted with the lowest fluence, the Eu3+ emission arises mainly from Eu incorporated inside the QDs while for the higher fluences only the emission from Eu inside the AlN-buffer, capping, and spacer layers is observed.
© 2010 American Institute of PhysicsFCT-PTDC/CTM/100756/2008program PESSOA EGIDE/GRICESFCT-SFRH/BD/45774/2008FCT-SFRH/BD/44635/200
The HARPS search for southern extra-solar planets XXXII. Only 4 planets in the Gl~581 system
The Gl 581 planetary system has generated wide interest, because its 4
planets include both the lowest mass planet known around a main sequence star
other than the Sun and the first super-Earth planet in the habitable zone of
its star. A recent paper announced the possible discovery of two additional
super-Earth planets in that system, one of which would be in the middle of the
habitable zone of Gl 581. The statistical significance of those two discoveries
has, however, been questioned. We have obtained 121 new radial velocity
measurements of Gl 581 with the HARPS spectrograph on the ESO 3.6 m telescope,
and analyse those together with our previous 119 measurements of that star to
examine these potential additional planets. We find that neither is likely to
exist with their proposed parameters. We also obtained photometric observations
with the 2.5 m Isaac Newton Telescope during a potential transit of the inner
planet, Gl 581e, which had a 5% geometric transit probability. Those
observations exclude transits for planet densities under 4 times the Earth
density within -0.2 sigma to +2.7 sigma of the predicted transit center.Comment: Submitted to Astronomy & Astrophysic
Repelência de entomopatógenos a Telenomus remus em condições de laboratório.
A utilização de agentes de controle biológico concomitantemente pode provocar interações de diferentes naturezas em ambos. O objetivo deste estudo foi de observar a repelência com e sem chance de escolha entre entomopatógenos e T. remus. Com chance de escolha os tratamentos foram: Baculovirus AEE (Baculovirus anticarsia-VPNAg), Thuricide (Bacillus thuringiensis var. kurstaki), Agree (B. thuringiensis var. aizawai) e Dipel WG (B. thuringiensis var. kurstaki), Boveril EP (Beauveria bassiana), Metarril EP (Metarhizium anisopliae), Trichodermil EP (Trichoderma harzianum), testemunha positiva Lorsban 480BR (clorpirifós) e sem chance de escolha adicionou-se testemunha sem tratamento (negativa). No estudo com chance, em gaiolas, foram oferecidas a T. remus cartelas com ovos de Spodoptera frugiperda, uma tratada e outra não tratada, no primeiro e segundo dia após a emergência dos adultos (DAE). Sem chance, somente cartelas tratadas foram oferecidas em 1 e 2DAE. Avaliou-se: porcentagem de parasitismo (parasitismo) e de parasitóides emergidos (viabilidade). Sem chance de escolha, 1DAE clorpirifós inibiu, com parasitismo de 9,33% e viabilidade de 13,33% e 2DAE clorpirifós 0% e Dipel 13,33% com menor parasitismo. Aos 2DAE maiores parasitismos foram observados para Metarril, 88,76%, Boveril 85,79%, e Trichodermil 86,17% e maiores viabilidades para Baculovirus 98,44%, Dipel 91,34% e Trichodermil 91,29%. Com chance, 1DAE o parasitismo diferiu em: Baculovirus não pulverizado (NP) 71,80% e pulverizado (P) 98,97%, Thuricide NP 90,23% e P 96,47%, Agree NP 93,36% e P 73,18%, Trichodermil NP 85,44% e P 100%, clorpirifós NP 84,22% e P 20,77%. A viabilidade foi: de 96,23% Baculovirus NP e 87,58% P; 97,82% para clorpirifós NP e 3,13% P. Aos 2DAE o parasitismo foi: 50,41% Agree NP e 73,67% P; 91,31% Boveril NP e 98,57%P: 92,26% clorpirifós NP e 0,16% P. Os demais tratamentos e condições não diferiram
Seletividade de entomopatógenos a telenomus remus em condições de laboratório segundo metodologia adaptada da International Organization for Biological Control (IOBC).
No controle biológico dos insetos dois ou mais agentes podem ser utilizados de forma conjunta, por exemplo, um entomopatógeno e um parasitóide. O objetivo deste estudo foi observar as interações entre dois agentes de controle biológico. Para tanto foram feitos dois experimentos (pupa e adulto) segundo as normas padronizadas da International Organization for Biological Control (IOBC). Os tratamentos foram: Baculovirus AEE (Baculovirus anticarsia-VPNAg), Thuricide (Bacillus thuringiensis var. kurstaki), Agree (B. thuringiensis var. aizawai) e Dipel WG (B. thuringiensis var. kurstaki), Boveril EP (Beauveria bassiana), Metarril EP (Metarhizium anisopliae), Trichodermil EP (Trichoderma harzianum) e testemunhas, Lorsban 480BR - clorpirifós (positiva) e água (negativa). Os parâmetros avaliados até dois dias após a emergência dos adultos (DAE) foram: porcentagem de parasitismo (parasitismo) e porcentagem de parasitoides emergidos (viabilidade). No ensaio com adultos, só o clorpirifós diferiu dos demais para parasitismo. No 1DAE o tratamento que apresentou maior viabilidade do parasitismo por T. remus foi Baculovirus (99,74%) e o menor foi Agree (97,38%), todavia, todos os tratamentos, exceto clorpirifós foram classificados como inócuos segundo as normas da IOBC. No experimento com pupas, clorpirifós diminuiu a viabilidade destas. No 1DAE e no 2DAE não houve diferença estatística entre os tratamentos em relação a viabilidade do parasitismo de T. remus. Já em relação a parasitismo tanto no 1DAE quanto no 2DAE houve diferença entre os tratamentos, no entanto somente Dipel no 2DAE foi considerado levemente nocivo e clorpirifós nocivo segundo a IOBC
Gauging the SU(2) Skyrme model
In this paper the SU(2) Skyrme model will be reformulated as a gauge theory
and the hidden symmetry will be investigated and explored in the energy
spectrum computation. To this end we purpose a new constraint conversion
scheme, based on the symplectic framework with the introduction of Wess-Zumino
(WZ) terms in an unambiguous way. It is a positive feature not present on the
BFFT constraint conversion. The Dirac's procedure for the first-class
constraints is employed to quantize this gauge invariant nonlinear system and
the energy spectrum is computed. The finding out shows the power of the
symplectic gauge-invariant formalism when compared with another constraint
conversion procedures present on the literature.Comment: revised version, to appear in Phys.Rev.
Remapping algorithms: application to trimming operations in sheet metal forming
Most of sheet metal forming processes comprise intermediate trimming operations to remove superfluous material. These operations are required for subsequent forming operations. On the other hand, the springback is strongly influenced by the trimming operations that change the part stiffness and the stress field. From the numerical point of view, this involves the geometrical trimming of the finite element mesh and subsequent remapping of the state variables. This study presents a remapping method based on Dual Kriging interpolation, specifically developed for hexahedral finite elements, which has been implemented in DD3TRIM in-house code. Its performance is compared with the one of the Incremental Volumetric Remapping method, using the split-ring test to highlight their advantages and limitations. The numerical simulation of the forming processes is performed with DD3IMP finite element solver.The authors gratefully acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) under the projects with reference UID/EMS/00285/2013, PTDC/EMS-TEC/0702/2014 (POCI-01-0145-FEDER-016779) and PTDC/EMS-TEC/6400/2014 (POCI-01-0145-FEDER-016876) by UE/FEDER through the program COMPETE2020. The first author is also grateful to the FCT for the Postdoctoral grant SFRH/BPD/101334/2014.info:eu-repo/semantics/publishedVersio
The HARPS search for southern extra-solar planets XXXV. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543
Context. Planetary companions of a fixed mass induce larger amplitude reflex
motions around lower-mass stars, which helps make M dwarfs excellent targets
for extra-solar planet searches. State of the art velocimeters with 1m/s
stability can detect very low-mass planets out to the habitable zone of these
stars. Low-mass, small, planets are abundant around M dwarfs, and most known
potentially habitable planets orbit one of these cool stars.
Aims. Our M-dwarf radial velocity monitoring with HARPS on the ESO 3.6m
telescope at La Silla observatory makes a major contribution to this sample.
Methods. We present here dense radial velocity (RV) time series for three M
dwarfs observed over years: GJ 3293 (0.42M), GJ 3341
(0.47M), and GJ 3543 (0.45M). We extract those RVs through
minimum matching of each spectrum against a high S/N ratio stack of
all observed spectra for the same star. We then vet potential orbital signals
against several stellar activity indicators, to disentangle the Keplerian
variations induced by planets from the spurious signals which result from
rotational modulation of stellar surface inhomogeneities and from activity
cycles.
Results. Two Neptune-mass planets - and
- orbit GJ 3293 with periods d and
d, possibly together with a super-Earth -
- with period . A super-Earth
- - orbits GJ 3341 with . The RV
variations of GJ 3543, on the other hand, reflect its stellar activity rather
than planetary signals.Comment: Accepted for publication in A&A, 19 pages, 12 figures, 7 table
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