473 research outputs found
The ground state of binary systems with a periodic modulation of the linear coupling
We consider a quasi-one-dimensional two-component systm, described by a pair
of Nonlinear Schr\"{o}dinger/Gross-Pitaevskii Equations (NLSEs/GPEs), which are
coupled by the linear mixing, with local strength , and by the
nonlinear incoherent interaction. We assume the self-repulsive nonlinearity in
both components, and include effects of a harmonic trapping potential. The
model may be realized in terms of periodically modulated slab waveguides in
nonlinear optics, and in Bose-Einstein condensates too. Depending on the
strengths of the linear and nonlinear couplings between the components, the
ground states (GSs) in such binary systems may be symmetric or asymmetric. In
this work, we introduce a periodic spatial modulation of the linear coupling,
making an odd, or even function of the coordinate. The sign flips of
strongly modify the structure of the GS in the binary system, as
the relative sign of its components tends to lock to the local sign of . Using a systematic numerical analysis, and an analytical approximation, we
demonstrate that the GS of the trapped system contains one or several kinks
(dark solitons) in one component, while the other component does not change its
sign. Final results are presented in the form of maps showing the number of
kinks in the GS as a function of the system's parameters, with the odd/even
modulation function giving rise to the odd/even number of the kinks. The
modulation of also produces a strong effect on the transition
between states with nearly equal and strongly unequal amplitudes of the two
components.Comment: 8 pages, 3 figure
Nasal IL-13 production identifies patients with late phase allergic responses
BACKGROUND: There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regards to the "late allergic response" (LAR) which occurs in approximately 40-50% of allergic patients. OBJECTIVE: In this study we aimed to characterise the immunological and clinical nasal responses to birch pollen allergen challenge with a special focus on the LAR. METHODS: In this randomised double-blinded placebo-control trial, birch pollen allergic participants were challenged with pollen extract (n=20) or placebo (n=10) on three consecutive days. On days one and three nasal secretions were collected at selected time points over a 24h time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements. RESULTS: Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and sST2 within minutes compared to placebo. Eight out of 20 provoked participants displayed high IL-13 levels 2-8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction which significantly differed from IL-13 non responders at 6 hours. CONCLUSION: IL-13 response status correlates with cytokine and clinical responses in the late phase after allergen provocation
Allergen-Specific Antibodies Regulate Secondary Allergen-Specific Immune Responses
Immunoglobulin E (IgE)-associated allergy is the most common immunologically-mediated hypersensensitivity disease. It is based on the production of IgE antibodies and T cell responses against per se innocuous antigens (i.e., allergens) and subsequent allergen-induced inflammation in genetically pre-disposed individuals. While allergen exposure in sensitized subjects mainly boosts IgE production and T cell activation, successful allergen-specific immunotherapy (AIT) induces the production of allergen-specific IgG antibodies and reduces T cell activity. Under both circumstances, the resulting allergen-antibody complexes play a major role in modulating secondary allergen-specific immune responses: Allergen-IgE complexes induce mast cell and basophil activation and perpetuate allergen-specific T cell responses via presentation of allergen by allergen presenting cells to T cells, a process called IgE-facilitated antigen presentation (FAP). In addition, they may induce activation of IgE memory B cells. Allergen-induced production of specific IgGs usually exerts ameliorating effects but under certain circumstances may also contribute to exacerbation. Allergen-specific IgG antibodies induced by AIT which compete with IgE for allergen binding (i.e., blocking IgG) inhibit formation of IgE-allergen complexes and reduce activation of effector cells, B cells and indirectly T cells as FAP is prevented. Experimental data provide evidence that by binding of allergen-specific IgG to epitopes different from those recognized by IgE, allergen-specific IgG may enhance IgE-mediated activation of mast cells, basophils and allergen-specific IgE+ B cells. In this review we provide an overview about the role of allergen-specific antibodies in regulating secondary allergen-specific immune responses
Looking ahead at the potential benefits of biotechnology-derived allergen therapeutics
While biotechnology-derived allergen therapeutics show promise in improving the safety of immunotherapy, they may prove to have additional benefits in comparison to conventional allergenic extracts that deserve commentary. These issues range from product stability and compatibility to medical practice issues, which will be the focus of this article
The challenges of ethical research with children
As especificidades da pesquisa com crianças têm ganhado visibilidade nas produções acadêmicas em diversas áreas de
conhecimento, com destaque para a Sociologia da Infância, principalmente a partir dos “novos estudos sobre a infância”
os quais emergiram ao final da década de 1980. Essa visibilidade acontece devida a questões como: a discussão sobre
as imagens da infância, construídas socio-historicamente; o reconhecimento da condição das crianças enquanto atores
sociais, portanto, seres competentes, que atribuem significações a suas experiências e contextos; e o reconhecimento
das crianças enquanto sujeitos de direitos, reconhecimento este pautado pela Doutrina da Proteção Integral. Permeadas
por essas questões, as pesquisas com crianças agregam a questão da Ética nas atividades desenvolvidas na relação
pesquisador-criança. No contexto dessa discussão, este trabalho propõe refletir sobre essas questões e os cuidados
éticos nesse tipo de pesquisa, considerando a condição da criança enquanto sujeito de direitos. Foi realizado um
recorte da produção acadêmica representativa na área da Sociologia da Infância nas duas últimas décadas, identificando
quais aspectos aparecem nas preocupações dos autores, quais abordagens norteiam a discussão desses aspectos e,
principalmente, que concepção de infância está presente nessa produção.The specificities of research with children have gained visibility in scientific publications in various areas of knowledge,
especially in Sociology of Childhood and the “new studies of childhood”, which emerged at the end of the 1980s. This
fact is due to discussions about childhood from a socio-historical perspective; the recognition of children as social
actors and therefore able to give meaning to their experiences and contexts; and the recognition of children as
individuals entitled to rights, according to the Doutrina da Proteção Integral (Full Protection Doctrine). Therefore,
research ethics is an essential element of good research governance, especially in terms of activities related to the
relationship between the researcher and child. Accordingly, the objective of this study is to examine and explore these
issues, considering the child as an individual entitled to rights. A literature review of articles published in the last two
decades in the area of Sociology of Childhood was conducted to identify the main issues and topics addressed, the
approaches that guided the discussions and, especially, to identify the conception of childhood present in these
studies.CIEC - Centro de Investigação em Estudos da Criança, IE, UMinho (UI 317 da FCT), Portuga
Preparation and characterization of stable aqueous suspensions of up-converting Er3+/Yb3+-doped LiNbO3 nanocrystals
The preparation of LiNbO3:Er3+/Yb3+ nanocrystals and their up-conversion properties have been studied. It is demonstrated that polyethyleneimine- (PEI) assisted dispersion procedures allow obtaining stable aqueous LiNbO3:Er3+/Yb3+ powder suspensions, with average size particles well below the micron range (100–200 nm) and the isoelectric point of the suspension reaching values well above pH 7. After excitation of Yb3+ ions at a wavelength of 980 nm, the suspensions exhibit efficient, and stable, IR-to-visible (green and red) up-conversion properties, easily observed by the naked eye, very similar to those of the starting crystalline bulk material
Non-solvolytic synthesis of aqueous soluble TiO2 nanoparticles and real-time dynamic measurements of the nanoparticle formation.
Highly aqueously dispersible (soluble) TiO2 nanoparticles are usually synthesized by a solution-based sol-gel (solvolysis/condensation) process, and no direct precipitation of titania has been reported. This paper proposes a new approach to synthesize stable TiO2 nanoparticles by a non-solvolytic method - direct liquid phase precipitation at room temperature. Ligand-capped TiO2 nanoparticles are more readily solubilized compared to uncapped TiO2 nanoparticles, and these capped materials show distinct optical absorbance/emission behaviors. The influence of ligands, way of reactant feeding, and post-treatment on the shape, size, crystalline structure, and surface chemistry of the TiO2 nanoparticles has been thoroughly investigated by the combined use of X-ray diffraction, transmission electron microscopy, UV-visible (UV-vis) spectroscopy, and photoluminescence (PL). It is found that all above variables have significant effects on the size, shape, and dispersivity of the final TiO2 nanoparticles. For the first time, real-time UV-vis spectroscopy and PL are used to dynamically detect the formation and growth of TiO2 nanoparticles in solution. These real-time measurements show that the precipitation process begins to nucleate after an initial inhibition period of about 1 h, thereafter a particle growth occurs and reaches the maximum point after 2 h. The synthesis reaction is essentially completed after 4 h.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Standardizing definitions and reporting guidelines for the infertility core outcome set : an international consensus development study
Acknowledgments We would like to thank the consensus development meeting participants and colleagues at the Cochrane Gynaecology and Fertility Group, University of Auckland, New Zealand. Funding This research was funded by the Catalyst Fund, Royal Society of New Zealand, Auckland Medical Research Fund and Maurice and Phyllis Paykel Trust. The funder had no role in the design and conduct of the study, the collection, management, analysis or interpretation of data or manuscript preparation. Siladitya Bhattacharya was supported by the University of Auckland Foundation Seelye Travelling Fellowship. B.W.M. is supported by a National Health and Medical Research Council Practitioner Fellowship (GNT1082548) This article has not been externally peer reviewed. This article has been published simultaneously in Fertility and SterilityPeer reviewedPublisher PD
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