Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Polymers (Basel) ; 14(20)2022 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-36297934

RESUMO

A superhydrophobic composite coating consisting of polytetrafluoroethylene (PTFE) and poly(acrylic acid)+ ß-cyclodextrin (PAA + ß-CD) was prepared on an aluminum alloy AA 6061T6 substrate by a three-step process of electrospinnig, spin coating, and electrospraying. The electrospinning technique is used for the fabrication of a polymeric binder layer synthesized from PAA + ß-CD. The superhydrophilic characteristic of the electrospun PAA + ß-CD layer makes it suitable for the absorption of an aqueous suspension with PTFE particles in a spin-coating process, obtaining a hydrophobic behavior. Then, the electrospraying of a modified PTFE dispersion forms a layer of distributed PTFE particles, in which a strong bonding of the particles with each other and with the PTFE particles fixed in the PAA + ß-CD fiber matrix results in a remarkable improvement of the particles adhesion to the substrate by different heat treatments. The experimental results corroborate the important role of obtaining hierarchical micro/nano multilevel structures for the optimization of superhydrophobic surfaces, leading to water contact angles above 170°, very low contact angle of hysteresis (CAH = 2°) and roll-off angle (αroll−off < 5°). In addition, a superior corrosion resistance is obtained, generating a barrier to retain the electrolyte infiltration. This study may provide useful insights for a wide range of applications.

2.
J Phys Condens Matter ; 34(33)2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35654034

RESUMO

Surface nanopatterning induced by ion beam irradiation (IBI) has emerged as an effective nanostructuring technique since it induces patterns on large areas of a wide variety of materials, in short time, and at low cost. Nowadays, two main subfields can be distinguished within IBI nanopatterning depending on the irrelevant or relevant role played by the surface composition. In this review, we give an up-dated account of the progress reached when surface composition plays a relevant role, with a main focus on IBI surface patterning with simultaneous co-deposition of foreign atoms. In addition, we also review the advances in IBI of compound surfaces as well as IBI systems where the ion employed is not a noble gas species. In particular, for the IBI with concurrent metal co-deposition, we detail the chronological evolution of these studies because it helps us to clarify some contradictory early reports. We describe the main patterns obtained with this technique as a function of the foreign atom deposition pathway, also focusing in those systematic studies that have contributed to identify the main mechanisms leading to the surface pattern formation and development. Likewise, we explain the main theoretical models aimed at describing these nanopattern formation processes. Finally, we address two main special features of the patterns induced by this technique, namely, the enhanced pattern ordering and the possibility to produce both morphological and chemical patterns.

3.
Nanoscale ; 12(12): 6603-6608, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32181455

RESUMO

The gallium-68 radiolabelling of new functional graphene oxide composites is reported herein along with kinetic stability investigations of the radio-nanohybrids under different environments and insights into their surface characteristics by SEM and XPS. The present work highlights the potential of graphene oxides as nanocarriers for small molecules such as bis(thiosemicarbazonato) complexes to act as multifunctional platforms for rapid and effective radioimaging agent incorporation.

4.
Sci Total Environ ; 711: 134644, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32000319

RESUMO

The present study describes the preparation of 50.3 nm superparamagnetic nanosorbents with high surface area for the adsorptive removal of lead and methyl orange from water. This material is based on the surface modification of iron oxide superparamagnetic nanoparticles with a double-shell coating of mesoporous silica whose porosity was increased up to 570 m2/g by the addition of a porogenic material and its calcination. The adsorptive performance of the nanosorbent was evaluated as a function of several parameters (e.g. solution pH, pollutant initial concentration, and contact time), concluding that pHs around 5 are needed to avoid precipitation of Pb2+ as Pb(OH)2 and the equilibrium adsorption capacity is reached after 2 h in all cases. The experimental data on the adsorption capacity of lead and methyl orange onto the nanosorbent were fit to a pseudo-second order kinetic model and Langmuir isotherm model. The maximum adsorption capacity value increases from 35 up to 50 mg/gNS for lead removal with increasing nanosorbent surface area. Contrary, for methyl orange the maximum adsorption goes up to 240 mg/gNS, indicating a larger nanosorbent surface affinity for the organic matter that is able to diffuse through the silica pores as probed by the intraparticle diffusion model. In addition, we found an good reusability (100% recovering after 4 sorption/desorption cycles for methyl orange removal), which makes of this magnetic nanosorbent suitable for remediation technologies.

5.
Anal Bioanal Chem ; 411(9): 1887-1894, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30324259

RESUMO

Alpha-1-acid glycoprotein (AGP) is a serum glycoprotein whose levels are increased two or three times during disease or injury. This makes it a potential biomarker for inflammatory bowel diseases and sepsis. Consequently, fast, simple, and cheap analytical methods for prognosis, diagnosis, and follow-up of these diseases are demanded. In this work, we propose a simple electrochemical approach based on carbon nanotubes scaffold films (CNSFs) for total AGP determination in serum samples. Firstly, AGP is labeled with an electrochemical tag (osmium(VI) complex), and then the total amount of AGP is quantified by adsorptive transfer stripping square wave voltammetry (AdTSWV). Multi-walled carbon nanotubes scaffold films (MWSFs) yielded the best analytical performance in terms of sensitivity with a good limit of detection of 0.6 mg L-1 for AGP determination in serum samples, in less than 20 min. A simplified AGP calibration and its sequential serum sample analysis strategy with good accuracy (81%) and excellent reproducibility (RSD < 1%) was additionally proposed to meet the point-of-care/needs requirements. Graphical abstract Multi-walled carbon nanotubes scaffold films for total AGP determination on disposable platforms integrating single-point calibration and sequential sample analysis.


Assuntos
Técnicas Eletroquímicas/métodos , Nanotubos de Carbono/química , Orosomucoide/análise , Adsorção , Calibragem , Humanos , Limite de Detecção , Osmio/química , Espectroscopia Fotoeletrônica , Sistemas Automatizados de Assistência Junto ao Leito , Reprodutibilidade dos Testes , Soro
6.
Biomaterials ; 192: 461-474, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30502723

RESUMO

Neural diseases at the central nervous system including spinal cord injury (SCI) remain therapeutic challenges. Graphene materials are being delineated as alternative tools for neural repair. Herein, the regenerative ability of reduced graphene oxide (rGO) scaffolds to support pivotal features of neural repair at 4 months after SCI is assessed by an interdisciplinary approach. 3D randomly porous foams have been prepared in mechanical compliance with neural cells and tissues (Young's modulus of 1.3 ±â€¯1.0 kPa) as demonstrated by atomic force microscopy techniques applied ex vivo. After implantation, the significant increase in Young's modulus caused by massive cell/protein infiltration does not alter the mechanical performance of the contralateral spinal cord but provides mechanical stability to the lesion. These aerogels appear fully vascularized and populated with neurites, some of them being myelinated excitatory axons. Clinically-inspired magnetic resonance imaging studies demonstrate that the scaffolds significantly reduce perilesional damage with respect to rats without implants and cause no compressive damage in the contralateral hemicord and rostral/caudal regions. The rGO implants do not either alter the rat spontaneous behaviour or induce toxicity in major organs. Finally, preliminary data suggest hints of rGO sheets dissociation and eventual degradation at the injured spinal cord for the first time. In summary, these 3D porous rGO scaffolds are able to induce, without any further biological functionalization, a compilation of positive effects that have been rarely described before, if ever, for any other material implanted in the injured spinal cord.


Assuntos
Materiais Biocompatíveis/uso terapêutico , Grafite/uso terapêutico , Regeneração Nervosa , Traumatismos da Medula Espinal/terapia , Animais , Axônios/patologia , Materiais Biocompatíveis/química , Grafite/química , Masculino , Neovascularização Fisiológica , Ratos , Ratos Wistar , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/fisiopatologia , Alicerces Teciduais/química
7.
ACS Appl Mater Interfaces ; 10(46): 40054-40061, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30418740

RESUMO

Direct, robust, and high-resolution patterning methods are needed to downscale the lateral size of two-dimensional materials to observe new properties and optimize the overall processing of these materials. In this work, we report a fabrication process where the initial microchannel of a few-layer WSe2 field-effect transistor is treated by oxygen plasma to form a self-limited oxide layer on top of the flake. This thin oxide layer has a double role here. First, it induces the so-called p-doping effect in the device. Second, it enables the fabrication of oxide nanoribbons with controlled width and depth by oxidation scanning probe lithography (o-SPL). After the removal of the oxides by deionized H2O etching, a nanoribbon-based field-effect transistor is produced. Oxidation SPL is a direct writing technique that minimizes the use of resists and lithographic steps. We have applied this process to fabricate a 5 nm thick WSe2 field-effect transistor, where the channel consists in an array of 5 parallel 350 nm half-pitch nanoribbons. The electrical measurements show that the device presents an improved conduction level compared to the starting thin-layer transistor and a positive threshold voltage shift associated to the p-doping treatment. The method enables to pattern devices with sub-50 nm feature sizes. We have patterned an array of 10 oxide nanowires with 36 nm half-pitch by oxidation SPL.

8.
Nanotechnology ; 29(35): 355707, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-29888710

RESUMO

Core-shell gallium nanoparticles (Ga NPs) have recently been proposed as an ultraviolet plasmonic material for different applications but only at room temperature. Here, the thermal stability as a function of the size of the NPs is reported over a wide range of temperatures. We analyze the chemical and structural properties of the oxide shell by x-ray photoelectron spectroscopy and atomic force microscopy. We demonstrate the inverse dependence of the shell breaking temperature with the size of the NPs. Spectroscopic ellipsometry is used for tracking the rupture and its mechanism is systematically investigated by scanning electron microscopy, grazing incidence x-ray diffraction and cathodoluminescence. Taking advantage of the thermal stability of the NPs, we perform complete oxidations that lead to homogenous gallium oxide NPs. Thus, this study set the physical limits of Ga NPs to last at high temperatures, and opens up the possibility to achieve totally oxidized NPs while keeping their sphericity.

9.
J Phys Chem Lett ; 9(11): 3124-3130, 2018 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-29781617

RESUMO

Compositional changes taking place during the synthesis of alloyed CdSeZnS nanocrystals (NCs) allow shifting of the optical features to higher energy as the NCs grow. Under certain synthetic conditions, the effect of those changes on the surface/interface chemistry competes with and dominates over the conventional quantum confinement effect in growing NCs. These changes, identified by means of complementary advanced spectroscopic techniques such as XPS (X-ray photoelectron spectroscopy) and XAS (X-ray absorption spectroscopy), are understood in the frame of an ion migration and exchange mechanism taking place during the synthesis. Control over the synthetic routes during NC growth represents an alternative tool to tune the optical properties of colloidal quantum dots, broadening the versatility of the wet chemical methods.

10.
J Phys Condens Matter ; 30(27): 274001, 2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29794326

RESUMO

We have bombarded crystalline silicon targets with a 40 keV Fe+ ion beam at different incidence angles. The resulting surfaces have been characterized by atomic force, current-sensing and magnetic force microscopies, scanning electron microscopy, and x-ray photoelectron spectroscopy. We have found that there is a threshold angle smaller than 40° for the formation of ripple patterns, which is definitely lower than those frequently reported for noble gas ion beams. We compare our observations with estimates of the value of the critical angle and of additional basic properties of the patterning process, which are based on a continuum model whose parameters are obtained from binary collision simulations. We have further studied experimentally the ripple structures and measured how the surface slopes change with the ion incidence angle. We explore in particular detail the fluence dependence of the pattern for an incidence angle value (40°) close to the threshold. Initially, rimmed holes appear randomly scattered on the surface, which evolve into large, bug-like structures. Further increasing the ion fluence induces a smooth, rippled background morphology. By means of microscopy techniques, a correlation between the morphology of these structures and their metal content can be unambiguously established.

11.
J Phys Condens Matter ; 30(26): 264003, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29762135

RESUMO

The surface morphology of molybdenum silicide (Mo x Si1-x ) films has been studied after low-energy Ar+ ion beam sputtering (IBS) to explore eventual pattern formation on compound targets and, simultaneously, gather information about the mechanisms behind silicide-assisted nanopatterning of silicon surfaces by IBS. For this purpose, Mo x Si1-x films with compositions below, equal and above the MoSi2 stoichiometry (x = 0.33) have been produced by magnetron sputtering, as assessed by Rutherford backscattering spectrometry (RBS). The surface morphology of silicon and silicide films before and after IBS has been imaged by atomic force microscopy (AFM), comprising conditions where typical nanodot or ripple patterns emerge on the former. In the case of irradiated Mo x Si1-x surfaces, AFM shows a marked surface smoothing at normal incidence with and without additional Mo incorporation (the former results in nanodot patterns on Si). The morphological analysis also provides no evidence of ion-induced phase separation in irradiated Mo x Si1-x . Contrary to silicon, Mo x Si1-x surfaces also do not display ripple formation for (impurity free) oblique irradiations, except at grazing incidence conditions where parallel ripples emerge in a more evident fashion than in the Si counterpart. By means of RBS, irradiated Mo x Si1-x films with 1 keV Ar+ at normal incidence have also been used to measure experimentally the (absolute) sputtering yield and rate of Si and Mo x Si1-x materials. The analysis reveals that, under the present working conditions, the erosion rate of silicides is larger than for silicon, supporting simulations from the TRIDYN code. This finding questions the shielding effect from silicide regions as roughening mechanism in metal-assisted nanopatterning of silicon. On the contrary, the results highlight the relevance of in situ silicide formation. Ripple formation on Mo x Si1-x under grazing incidence is also attributed to the dominance of sputtering effects under this geometry. In conclusion, our work provides some insights into the complex morphological evolution of compound surfaces and solid experimental evidences regarding the mechanisms behind silicide-assisted nanopatterning.

12.
Sci Rep ; 7(1): 11949, 2017 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-28931869

RESUMO

Subcutaneous specific immunotherapy (SCIT) has been shown to modify the Dermatophagoides pteronissinus (DP) allergic response, characterized by generation of Treg cells. However, studies have reported no changes in the proportion of Treg cells after immunotherapy, indicating that the effects may be due to modifications in their regulatory activities. We aimed to determine whether Tregs generated by DP-SCIT can switch the allergic response to tolerant and study the involvement of suppressive cytokines on it. Twenty-four DP-allergic rhinitis patients were recruited, 16 treated with DP-SCIT and 8 untreated. Treg and T effector cells were isolated before and after DP-SCIT, and cocultured in different combinations with α-IL-10, α-TGF-ß blocking antibodies and nDer p 1. Treg cells after DP-SCIT increased Th1 and decreased Th2 and Th9 proliferation. Similarly, they increased IL-10 and decreased IL-4 and IL-9-producing cells. α-IL-10 affected the activity of Treg cells obtained after DP-SCIT only. Finally, DP-specific IgG4 levels, Treg percentage and IL-10 production were correlated after DP-SCIT. These results demonstrate that DP-SCIT induces Treg cells with different suppressive activities. These changes could be mediated by IL-10 production and appear to play an important role in the induction of the tolerance response leading to a clinical improvement of symptoms.


Assuntos
Antígenos de Dermatophagoides/administração & dosagem , Dermatophagoides pteronyssinus/imunologia , Imunoterapia/métodos , Rinite Alérgica/terapia , Linfócitos T Reguladores/imunologia , Adulto , Animais , Células Cultivadas , Técnicas de Cocultura , Feminino , Humanos , Injeções Subcutâneas , Masculino , Células Th1/imunologia , Células Th2/imunologia , Adulto Jovem
13.
Nanotechnology ; 28(40): 405705, 2017 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-28787277

RESUMO

The effect of the oxidation of gallium nanoparticles (Ga NPs) on their plasmonic properties is investigated. Discrete dipole approximation has been used to study the wavelength of the out-of-plane localized surface plasmon resonance in hemispherical Ga NPs, deposited on silicon substrates, with oxide shell (Ga2O3) of different thickness. Thermal oxidation treatments, varying temperature and time, were carried out in order to increase experimentally the Ga2O3 shell thickness in the NPs. The optical, structural and chemical properties of the oxidized NPs have been studied by spectroscopic ellipsometry, scanning electron microscopy, grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy. A clear redshift of the peak wavelength is observed, barely affecting the intensity of the plasmon resonance. A controllable increase of the Ga2O3 thickness as a consequence of the thermal annealing is achieved. In addition, simulations together with ellipsometry results have been used to determine the oxidation rate, whose kinetics is governed by a logarithmic dependence. These results support the tunable properties of the plasmon resonance wavelength in Ga NPs by thermal oxidation at low temperatures without significant reduction of the plasmon resonance intensity.

14.
Nanoscale ; 9(19): 6463-6470, 2017 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-28466930

RESUMO

Herein, gas phase synthesis and characterization of multifunctional core@shell, Au@TiOx nanoparticles have been reported. The nanoparticles were produced via a one-step process using a multiple-ion cluster source under a controlled environment that guaranteed the purity of the nanoparticles. The growth of the Au cores (6 nm diameter) is stopped when they pass through the Ti plasma where they are covered by an ultra-thin (1 nm thick) and homogeneous titanium shell that is oxidized in-flight before the soft-landing of the nanoparticles. The Au cores were found to be highly crystalline with icosahedral (44%) and decahedral (66%) structures, whereas the shell, mainly composed of TiO2 (79%), was not ordered. The highly electrical insulating behaviour of the titanium oxide shell was confirmed by the charging effect produced during X-ray photoemission spectroscopy.

15.
Phys Rev Lett ; 118(16): 164802, 2017 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-28474903

RESUMO

The generation of intense electron beams with low emittance is key to both the production of coherent x rays from free electron lasers, and electron pulses with large transverse coherence length used in ultrafast electron diffraction. These beams are generated today by photoemission from disordered polycrystalline surfaces. We show that the use of single crystal surfaces with appropriate electronic structures allows us to effectively utilize the physics of photoemission to generate highly directed electron emission, thus reducing the emittance of the electron beam being generated.

16.
Nanotechnology ; 27(44): 444001, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27670245

RESUMO

We have produced self-organised silicide nanodot patterns by medium-energy ion beam sputtering (IBS) of silicon targets with a simultaneous and isotropic molybdenum supply. Atomic force microscopy (AFM) studies show that these patterns are qualitatively similar to those produced thus far at low ion energies. We have determined the relevance of the ion species on the pattern ordering and properties. For the higher ordered patterns produced by Xe(+) ions, the pattern wavelength depends linearly on the ion energy. The dot nanostructures are silicide-rich as assessed by x-ray photoelectron spectroscopy (XPS) and emerge in height due to their lower sputtering yield, as observed by electron microscopy. Remarkably, a long wavelength corrugation is observed on the surface which is correlated with both the Mo content and the dot pattern properties. Thus, as assessed by electron microscopy, the protrusions are Mo-rich with higher and more spaced dots on their surface whereas the valleys are Mo-poor with smaller dots that are closer to each other. These findings indicate that there is a correlation between the local metal content of the surface and the nanodot pattern properties both at the nanodot and the large corrugation scales. These results contribute to advancing the understanding of this interesting nanofabrication method and aid in developing a comprehensive theory of nanodot pattern formation and evolution.

17.
Artigo em Inglês | MEDLINE | ID: mdl-27164623

RESUMO

BACKGROUND: Local allergic rhinitis (LAR) is a phenotype of allergic rhinitis characterized by the presence of a localized immune response in the nasal mucosa of patients with negative skin prick test (SPT) results and undetectable serum specific IgE (sIgE). It unknown whether LAR is limited to areas with low or moderate aeroallergen exposure. OBJECTIVE: To explore the presence of LAR and the clinical and immunological characteristics of this entity in geographic areas with high grass pollen loads. METHODS: A cross-sectional observational study was carried out in 2 hospitals in central Spain (Madrid and Ciudad Real). Sixty-one patients with seasonal rhinitis and negative SPT results and undetectable serum sIgE were evaluated using a clinical questionnaire, determination of serum total IgE, and a nasal allergen provocation test (NAPT) with Phleum species. The response to NAPT was monitored using assessment of nasal symptoms, acoustic rhinometry, and determination of sIgE, tryptase, and eosinophil cationic protein in the nasal cavity. RESULTS: Seasonal LAR was detected in 37 patients (61%) using the techniques described above. Eleven percent of patients with LAR were adolescents or children, and 14% reported onset of rhinitis in childhood. Most patients reported persistent-moderate seasonal nasal symptoms, and 41% reported worsening of the disease during the last 2 years. Conjunctivitis was the most common comorbidity, affecting 95% of cases. CONCLUSIONS: LAR to grass pollen is relevant in patients with seasonal symptoms indicative of allergic rhinitis but with a negative skin test result who live in areas with high allergenic pollen loads. This entity should be included the differential diagnosis of rhinitis.


Assuntos
Alérgenos/imunologia , Conjuntivite/imunologia , Mucosa Nasal/imunologia , Pólen/imunologia , Rinite Alérgica Sazonal/imunologia , Adolescente , Adulto , Idoso , Criança , Conjuntivite/sangue , Conjuntivite/complicações , Conjuntivite/patologia , Estudos Transversais , Proteína Catiônica de Eosinófilo/genética , Proteína Catiônica de Eosinófilo/imunologia , Feminino , Expressão Gênica , Humanos , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/patologia , Testes de Provocação Nasal , Phleum/química , Phleum/imunologia , Rinite Alérgica Sazonal/sangue , Rinite Alérgica Sazonal/complicações , Rinite Alérgica Sazonal/patologia , Estações do Ano , Testes Cutâneos , Inquéritos e Questionários , Triptases/genética , Triptases/imunologia
18.
J. investig. allergol. clin. immunol ; 26(2): 83-91, 2016. tab, graf
Artigo em Inglês | IBECS | ID: ibc-152597

RESUMO

Background: Local allergic rhinitis (LAR) is a phenotype of allergic rhinitis characterized by the presence of a localized immune response in the nasal mucosa of patients with negative skin prick test (SPT) results and undetectable serum specific IgE (sIgE). It unknown whether LAR is limited to areas with low or moderate aeroallergen exposure. Objective: To explore the presence of LAR and the clinical and immunological characteristics of this entity in geographic areas with high grass pollen loads. Methods: A cross-sectional observational study was carried out in 2 hospitals in central Spain (Madrid and Ciudad Real). Sixty-one patients with seasonal rhinitis and negative SPT results and undetectable serum sIgE were evaluated using a clinical questionnaire, determination of serum total IgE, and a nasal allergen provocation test (NAPT) with Phleum species. The response to NAPT was monitored using assessment of nasal symptoms, acoustic rhinometry, and determination of sIgE, tryptase, and eosinophil cationic protein in the nasal cavity. Results: Seasonal LAR was detected in 37 patients (61%) using the techniques described above. Eleven percent of patients with LAR were adolescents or children, and 14% reported onset of rhinitis in childhood. Most patients reported persistent-moderate seasonal nasal symptoms, and 41% reported worsening of the disease during the last 2 years. Conjunctivitis was the most common comorbidity, affecting 95% of cases. Conclusions: LAR to grass pollen is relevant in patients with seasonal symptoms indicative of allergic rhinitis but with a negative skin test result who live in areas with high allergenic pollen loads. This entity should be included the differential diagnosis of rhinitis (AU)


Introducción: La rinitis alérgica local (RAL) es un fenotipo de rinitis alérgica (RA) caracterizado por la presencia de una respuesta inmunológica localizada en la mucosa nasal de pacientes con pruebas cutáneas (PC) negativas e IgE específica (sIgE) sérica no detectable. Se desconoce si la RAL es una entidad limitada a áreas con baja o moderada exposición a aeroalérgenos. Objetivos: Explorar la presencia y características clínico-inmunológicas de la RAL en áreas geográficas con alta concentración atmosférica de polen de gramíneas. Métodos: Estudio observacional-transversal realizado en dos hospitales de la zona centro de España (Madrid y Ciudad Real). Sesenta y un pacientes con rinitis estacional, PC negativas y sIgE sérica no detectable fueron evaluados mediante cuestionario clínico, IgE total sérica, y test de provocación nasal con Phleum (TPN-Phleum). La respuesta al TPN se monitorizó mediante síntomas, rinometría acústica, y determinación de sIgE, triptasa y proteína catiónica de eosinófilos en secreciones nasales. Resultados: Se detectó RAL estacional en 37 pacientes (61%) mediante TPN-Phleum. El 11% de los pacientes eran adolescentes o niños, y el 14% habían comenzado con los síntomas en la infancia. La mayoría presentaban rinitis estacional persistente-moderada, y el 41% refirió empeoramiento en los 2 últimos años. La conjuntivitis fue la enfermedad asociada más frecuente, afectando al 95% de los sujetos con RAL. Conclusiones: La RAL por polen de gramíneas es una enfermedad frecuente en pacientes con síntomas indicativos de RA estacional y PC negativas que viven en áreas con alta concentración atmosférica de pólenes, y debe ser incluida en el diagnostico diferencial de la rinitis (AU)


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Rinite Alérgica/complicações , Rinite Alérgica/diagnóstico , Rinite Alérgica/imunologia , Relação Dose-Resposta Imunológica , Hipersensibilidade Imediata/imunologia , Rinometria Acústica/métodos , Diagnóstico Diferencial , Poaceae/efeitos adversos , Imunidade nas Mucosas , Imunidade nas Mucosas/imunologia , Testes Cutâneos/métodos , Testes Cutâneos/tendências , Estudos Transversais/instrumentação , Estudos Transversais/métodos , Estudos Transversais , Inquéritos e Questionários
19.
Clin Exp Allergy ; 45(10): 1542-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26032922

RESUMO

BACKGROUND: Although specific immunotherapy is the only aetiological treatment for allergic disorders, the underlying mechanisms are not fully understood. Specific immunotherapy induces changes in lymphocyte Th subsets from Th2 to Th1/Treg. Whether differences in immunological patterns underlie patient response to immunotherapy has not yet been established. OBJECTIVES: We studied the immunological changes occurring during a 1-year period of Dermatophagoides pteronyssinus (DP) immunotherapy and their relation with clinical outcome. METHODS: We included 34 patients with DP allergy who received subcutaneous specific immunotherapy (SCIT) for 1 year. Following treatment, patients were classified as responders or non-responders. Fourteen allergic subjects who did not receive SCIT were included as controls. Peripheral blood was obtained at 0, 1, 3, 6 and 12 months and cultured with nDer p 1. Phenotypic changes, cytokine production and basophil response were analysed by flow cytometry; transcription factors were measured by mRNA quantification. Serum immunoglobulin levels were also measured. RESULTS: After 1 year of SCIT, 82% of cases showed improved symptoms (responders). Although increases in sIgG4 were observed, BAT reactivity was not modified in these patients. Increases in T-BET/FOXP3 as well as nDer p 1-specific Th1/Treg frequencies were also observed, along with a decrease in Th2, Th9 and Th17. These changes corresponded to changes in cytokine levels. CONCLUSION: Patients who respond well to DP-SCIT show immunological differences compared to non-responders. In responders, basal differences include a lower frequency of Th1 and higher frequencies of Th2, Th9 and Th17 cells. After 1 year of treatment, an increased production of sIgG4 was observed in responders, along with a change in Th2 response towards Th1/Treg.


Assuntos
Citocinas/imunologia , Dermatophagoides pteronyssinus/imunologia , Dessensibilização Imunológica , Rinite Alérgica/imunologia , Rinite Alérgica/terapia , Linfócitos T Auxiliares-Indutores/imunologia , Adulto , Animais , Citocinas/sangue , Feminino , Seguimentos , Humanos , Masculino , Valor Preditivo dos Testes , Rinite Alérgica/sangue , Linfócitos T Auxiliares-Indutores/metabolismo
20.
Surf Sci ; 646: 5-12, 2015 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-27279673

RESUMO

We have deposited 4-aminophenol on Pt(111) surfaces in ultra-high vacuum and studied the strength of its adsorption through a combination of STM, LEED, XPS and ab initio calculations. Although an ordered (2√3×2√3)R30° phase appears, we have observed that molecule-substrate interaction dominates the adsorption geometry and properties of the system. At RT the high catalytic activity of Pt induces aminophenol to lose the H atom from the hydroxyl group, and a proportion of the molecules lose the complete hydroxyl group. After annealing above 420K, all deposited aminophenol molecules have lost the OH moiety and some hydrogen atoms from the amino groups. At this temperature, short single-molecule oligomer chains can be observed. These chains are the product of a new reaction that proceeds via the coupling of radical species that is favoured by surface diffusion.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA