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1.
Glob Chang Biol ; 30(3): e17236, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38519845

RESUMO

Climate change is restructuring biodiversity on multiple scales and there is a pressing need to understand the downstream ecological and genomic consequences of this change. Recent advancements in the field of eco-evolutionary genomics have sought to include evolutionary processes in forecasting species' responses to climate change (e.g., genomic offset), but to date, much of this work has focused on terrestrial species. Coastal and offshore species, and the fisheries they support, may be even more vulnerable to climate change than their terrestrial counterparts, warranting a critical appraisal of these approaches in marine systems. First, we synthesize knowledge about the genomic basis of adaptation in marine species, and then we discuss the few examples where genomic forecasting has been applied in marine systems. Next, we identify the key challenges in validating genomic offset estimates in marine species, and we advocate for the inclusion of historical sampling data and hindcasting in the validation phase. Lastly, we describe a workflow to guide marine managers in incorporating these predictions into the decision-making process.


Assuntos
Biodiversidade , Pesqueiros , Oceanos e Mares , Genômica , Mudança Climática , Ecossistema , Previsões
2.
Inorg Chem ; 63(19): 8908-8918, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38684934

RESUMO

This work is devoted to evaluating the relationship between the oxygen content and catalytic activity in the CO oxidation process of the 6H-type BaFeO3-δ system. Strong evidence is provided about the improvement of catalytic performance with increasing Fe average oxidation state, thus suggesting the involvement of lattice oxygen in the catalytic process. The compositional and structural changes taking place in both the anionic and cationic sublattices of the catalysts during redox cycles have been determined by temperature-resolved neutron diffraction. The obtained results evidence a structural transition from hexagonal (P63/mmc) to orthorhombic (Cmcm) symmetry. This transition is linked to octahedra distortion when the Fe3+ concentration exceeds 40% (δ values higher than 0.2). The topotactical character of the redox process is maintained in the δ range 0 < δ < 0.4. This suggests that the cationic framework is only subjected to slight structural modifications during the oxygen exchange process occurring during the catalytic cycle.

3.
Biol Res ; 55(1): 13, 2022 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-35313991

RESUMO

BACKGROUND: Tellurium is a rare metalloid that exerts high toxicity on cells, especially on bacteria, partly due to reactive oxygen species (ROS) generation. Moreover, it has also been observed that tellurite can target free cell thiols groups (RSH) (i.e. reduced glutathione (GSH)), enhancing the cellular redox imbalance. Additionally, in vitro experiments have suggested that several enzymes can reduce tellurite (IV) to its elemental form (0); where RSH present on their active sites may be responsible for the process. Nevertheless, the mechanisms implemented by bacteria for tellurite reduction and its role in resistance have not been evaluated in vivo. RESULTS: This work shows that tellurite reduction to elemental tellurium is increased under anaerobic conditions in E. coli cells. The in vivo tellurite reduction is related to the intracellular concentration of total RSH, in the presence and absence of oxygen. This metabolization of tellurite directly contributes to the resistance of the bacteria to the oxyanion. CONCLUSIONS: We demonstrated that in vivo tellurite reduction is related to the intracellular thiol concentration, i.e. large availability of cellular RSH groups, results in a more significant reduction of tellurite. Furthermore, we observed that, when the bacterium exhibits less resistance to the oxyanion, a decreased tellurite reduction was seen, affecting the growth fitness. Together, these results let us propose that tellurite reduction and the intracellular RSH content are related to the oxyanion bacterial resistance, this tripartite mechanism in an oxygen-independent anaerobic process.


Assuntos
Escherichia coli , Telúrio , Anaerobiose , Oxirredução
4.
Environ Geochem Health ; 44(8): 2783-2797, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34448062

RESUMO

Air pollutants (either of natural or anthropogenic origin) represent a considerable environmental risk to human health by affecting the respiratory system and causing respiratory disorders. In this study, we investigate the effects of chronic exposure to hydrothermal emissions on the nasal cavity of mice since it is the first and the most exposed region of the respiratory system. This study, carried in S. Miguel Island, Azores-Portugal, used Mus musculus as a bioindicator species. Mice were captured in an area with non-eruptive active volcanism (Furnas Village) and another area without volcanism (Rabo de Peixe, reference site). The hydrothermal emissions present at Furnas Village are characterized by the continuous release of several gases (CO2, H2S, 222Rn) along with metals (e.g. Hg, Cd, Zn, Al) and particulate matter into the environment. We test the hypothesis whether chronic exposure to this specific type of pollution causes epithelial morphometric, mucosecretory and neuronal alterations on the nasal cavity. Thickness measurements were taken in the squamous, respiratory and olfactory epithelia. The relative density of cell types (basal, support and neurons) was also assessed in the olfactory epithelium and the mucosecretory activity was determined in the lateral nasal glands, Bowman's gland and goblet cells. Mice chronically exposed to hydrothermal emissions presented thinner olfactory epithelia and lesser mucous production, which could result in loss of olfactory capabilities as well as a decrease in the protective function provided by the mucous to the lower respiratory tract. For the first time, it is demonstrated that, in mice, this specific type of non-eruptive active volcanism causes epithelial and mucosecretory alterations, leading to the loss of olfactory capabilities.


Assuntos
Poluentes Atmosféricos , Cavidade Nasal , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Animais , Gases , Metais , Camundongos , Cavidade Nasal/química , Material Particulado
5.
Hum Mol Genet ; 28(23): 4012-4021, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630202

RESUMO

Huntington's disease (HD) has traditionally been described as a disorder purely of the brain; however, evidence indicates that peripheral abnormalities are also commonly seen. Among others, severe unintended body weight loss represents a prevalent and often debilitating feature of HD pathology, with no therapies available. It correlates with disease progression and significantly affects the quality of life of HD patients. Curcumin, a naturally occurring polyphenol with multiple therapeutic properties, has been validated to exert important beneficial effects under health conditions as well as in different pathological settings, including neurodegenerative and gastrointestinal (GI) disorders. Here, we investigated the potential therapeutic action that curcumin-supplemented diet may exert on central and peripheral dysfunctions in R6/2 mice, a well-characterized HD animal model which recapitulates some features of human pathology. Maintenance of normal motor function, protection from neuropathology and from GI dysfunction and preservation of GI emptying and conserved intestinal contractility, proved the beneficial role of life-long dietary curcumin in HD and corroborated the potential of the compound to be exploited to alleviate very debilitating symptoms associated with the disease.


Assuntos
Comportamento Animal/efeitos dos fármacos , Curcumina/administração & dosagem , Doença de Huntington/dietoterapia , Redução de Peso/efeitos dos fármacos , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Curcumina/farmacologia , Suplementos Nutricionais , Modelos Animais de Doenças , Feminino , Doença de Huntington/fisiopatologia , Masculino , Camundongos , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Fenótipo
6.
Neurobiol Dis ; 143: 105009, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32634578

RESUMO

Emerging evidence indicates that Huntington's disease (HD) may be described as multi-organ pathology. In this context, we and others have contributed to demonstrate that the disease is characterized by an impairment of the homeostasis of gastro-intestinal (GI) tract. Sphingolipids represent a class of molecules involved in the regulation and maintenance of different tissues and organs including GI system. In this study, we investigated whether the alteration of Sphingosine-1-phosphate (S1P) metabolism, previously described in human HD brains and animal models, is also detectable peripherally in R6/2 HD mice. Our findings indicate, for the first time, that sphingolipid metabolism is perturbed early in the disease in the intestinal tract of HD mice and, its modulation by K6PC-5, a selective activator of S1P synthesis, preserved intestinal integrity and homeostasis. These results further support the evidence that modulation of sphingolipid pathways may represent a potential therapeutic option in HD and suggest that it has also the potential to counteract the peripheral disturbances which may usually complicate the management of the disease and affect patient's quality of life.


Assuntos
Amidas/farmacologia , Doença de Huntington/metabolismo , Intestinos/efeitos dos fármacos , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Animais , Modelos Animais de Doenças , Homeostase/efeitos dos fármacos , Lisofosfolipídeos/metabolismo , Camundongos , Fosfotransferases (Aceptor do Grupo Álcool)/efeitos dos fármacos , Esfingolipídeos/metabolismo , Esfingosina/análogos & derivados , Esfingosina/metabolismo
7.
J Nanobiotechnology ; 17(1): 106, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31615570

RESUMO

BACKGROUND: Improving the water solubility of hydrophobic drugs, increasing their accumulation in tumor tissue and allowing their simultaneous action by different pathways are essential issues for a successful chemotherapeutic activity in cancer treatment. Considering potential clinical application in the future, it will be promising to achieve such purposes by developing new biocompatible hybrid nanocarriers with multimodal therapeutic activity. RESULTS: We designed and characterised a hybrid nanocarrier based on human serum albumin/chitosan nanoparticles (HSA/chitosan NPs) able to encapsulate free docetaxel (DTX) and doxorubicin-modified gold nanorods (DOXO-GNRs) to simultaneously exploit the complementary chemotherapeutic activities of both antineoplasic compounds together with the plasmonic optical properties of the embedded GNRs for plasmonic-based photothermal therapy (PPTT). DOXO was assembled onto GNR surfaces following a layer-by-layer (LbL) coating strategy, which allowed to partially control its release quasi-independently release regarding DTX under the use of near infrared (NIR)-light laser stimulation of GNRs. In vitro cytotoxicity experiments using triple negative breast MDA-MB-231 cancer cells showed that the developed dual drug encapsulation approach produces a strong synergistic toxic effect to tumoral cells compared to the administration of the combined free drugs; additionally, PPTT enhances the cytostatic efficacy allowing cell toxicities close to 90% after a single low irradiation dose and keeping apoptosis as the main cell death mechanism. CONCLUSIONS: This work demonstrates that by means of a rational design, a single hybrid nanoconstruct can simultaneously supply complementary therapeutic strategies to treat tumors and, in particular, metastatic breast cancers with good results making use of its stimuli-responsiveness as well as its inherent physico-chemical properties.


Assuntos
Antineoplásicos/administração & dosagem , Docetaxel/administração & dosagem , Doxorrubicina/administração & dosagem , Nanocápsulas/química , Albumina Sérica Humana/química , Neoplasias de Mama Triplo Negativas/terapia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Preparações de Ação Retardada/química , Docetaxel/farmacologia , Doxorrubicina/farmacologia , Ouro/química , Humanos , Hipertermia Induzida , Luz , Nanotubos/química , Fotoquimioterapia , Fototerapia
8.
Curr Genet ; 63(2): 215-227, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27387518

RESUMO

Agrobacterium-mediated gene transfer (AMT) is extensively employed as a tool in fungal functional genomics and accordingly, in previous studies we used AMT on a dikaryotic strain of the ectomycorrhizal basidiomycete Laccaria bicolor. The interest in this fungus derives from its capacity to establish a symbiosis with tree roots, thereby playing a major role in nutrient cycling of forest ecosystems. The ectomycorrhizal symbiosis is a highly complex interaction involving many genes from both partners. To advance in the functional characterization of fungal genes, AMT was used on a monokaryotic L. bicolor. A collection of over 1200 transgenic strains was produced, of which 200 randomly selected strains were analyzed for their genomic T-DNA insertion patterns. By means of insertional mutagenesis, a number of transgenic strains were obtained displaying differential growth features. Moreover, mating with a compatible strain resulted in dikaryons that retained altered phenotypic features of the transgenic monokaryon. The analysis of the T-DNA integration pattern revealed mostly similar results to those reported in earlier studies, confirming the usefulness of AMT on different genetic backgrounds of L. bicolor. Taken together, our studies display the great versatility and potentiality of AMT as a tool for the genetic characterization of L. bicolor.


Assuntos
Agrobacterium/genética , Laccaria/genética , Mutagênese Insercional , Micorrizas/genética , Sequência de Bases , Sítios de Ligação/genética , Southern Blotting , DNA Bacteriano/genética , DNA Fúngico/genética , Proteínas Fúngicas/genética , Genoma Fúngico/genética , Análise de Sequência de DNA , Simbiose , Transformação Genética
9.
Inorg Chem ; 56(19): 11753-11761, 2017 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-28898062

RESUMO

The elucidation of the reaction mechanisms involving redox processes in functional transition-metal oxides, which usually start in areas of very few nanometers in size, is yet a challenge to be satisfactorily achieved. Atomically resolved HAADF and EELS have provided both chemical and structural information at the nanoscale, which reveal the preservation of short-range cationic order in areas of 2-3 nm length as the driving force behind the reversibility of the Ca2Mn3O8-Ca2Mn3O5 redox process. Oxygen evolution is accommodated by cationic diffusion along the Ca and Mn layers of the cation-deficient Ca2Mn3O8 delafossite related structure, whereas Mn remains octahedrally coordinated.

10.
Nano Lett ; 15(11): 7355-61, 2015 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-26484628

RESUMO

The functional properties of oxide heterostructures ultimately rely on how the electronic and structural mismatches occurring at interfaces are accommodated by the chosen materials combination. We discuss here LaMnO3/LaNiO3 heterostructures, which display an intrinsic interface structural asymmetry depending on the growth sequence. Using a variety of synchrotron-based techniques, we show that the degree of intermixing at the monolayer scale allows interface-driven properties such as charge transfer and the induced magnetic moment in the nickelate layer to be controlled. Further, our results demonstrate that the magnetic state of strained LaMnO3 thin films dramatically depends on interface reconstructions.

11.
J Appl Microbiol ; 118(6): 1264-75, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25728297

RESUMO

AIMS: Outbreaks of disease caused by some Vibrio species represent the main production bottleneck in shellfish hatcheries. Although the phytoplankton used as food is one of the main sources of bacteria, studies of the associated bacterial populations, specifically vibrios, are scarce. The aim of the study was the microbiological monitoring of the microalgae as the first step in assessing the risk disease for bivalve cultures. METHODS AND RESULTS: Two phytoplankton production systems were sampled weekly throughout 1-year period in a bivalve hatchery. Quantitative analysis revealed high levels of marine heterotrophic bacteria in both systems throughout the study. Presumptive vibrios were detected occasionally and at low concentrations. In most of the cases, they belonged to the Splendidus and Harveyi clades. CONCLUSIONS: The early detection of vibrios in the microalgae may be the key for a successful bivalve culture. Their abundance and diversity were affected by factors related to the hatchery environment. SIGNIFICANCE AND IMPACT OF THE STUDY: This work represents the first long study where the presence of vibrios was evaluated rigorously in phytoplankton production systems and provides a suitable microbiological protocol to control and guarantee the quality of the algal cultures to avoid the risk of transferring potential pathogens to shellfish larvae and/or broodstock.


Assuntos
Bivalves/microbiologia , Fitoplâncton/crescimento & desenvolvimento , Frutos do Mar/microbiologia , Vibrio/crescimento & desenvolvimento , Animais , Carga Bacteriana , Biodiversidade , Contaminação de Alimentos/análise , Dados de Sequência Molecular , Fitoplâncton/classificação , Fitoplâncton/genética , Fitoplâncton/isolamento & purificação , Vibrio/classificação , Vibrio/genética , Vibrio/isolamento & purificação
12.
Spinal Cord ; 53(7): 557-60, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25823803

RESUMO

STUDY DESIGN: Structured interview based on a predesigned survey. OBJECTIVE: To examine the factors that affect the degree of sexual satisfaction in a sample of women with spinal cord injury (SCI). SETTING: The study participants were women with SCIs, from the area of the SCI Unit of A Coruña, a reference unit for the Community of Galicia in the northwest of Spain. All study participants were selected consecutively in the outpatient clinic in 2013. METHODS: The study included women with the American Spinal Injury Association (ASIA) A-D spinal injuries, between the ages of 18 and 65 years, who completed rehabilitation therapy and live in the community. A total of 32 women formed the final study group. RESULTS: When comparing the group of women who were sexually active with those who were not, variables such as age, neurological level, time since the SCI, ASIA or Spinal Cord Independence Measure score, urinary incontinence, chronic pain and spasticity were not related to sexual activity. The only factors that we found to be related to sexual activity were not having a stable partner (P=0.017) and a lack of sensation in the genital area (P=0.039). CONCLUSION: The only variables related to sexual activity were not having a partner and a lack of sensation in the genital area. Improving sexual satisfaction, information and specific programs during rehabilitation can help women with SCI explore and investigate new erotic possibilities, thereby improving their self-esteem and social relationships.


Assuntos
Orgasmo/fisiologia , Comportamento Sexual/fisiologia , Disfunções Sexuais Fisiológicas/etiologia , Traumatismos da Medula Espinal/complicações , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Parceiros Sexuais
13.
Hum Brain Mapp ; 35(7): 3143-51, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24895252

RESUMO

Increased iron in subcortical gray matter (GM) structures of patients with Huntington's disease (HD) has been suggested as a causal factor in neuronal degeneration. But how iron content is related to white matter (WM) changes in HD is still unknown. For example, it is not clear whether WM changes share the same physiopathology (i.e. iron accumulation) with GM or whether there is a different mechanism. The present study used MRI to examine iron content in premanifest gene carriers (PreHD, n = 25) and in early HD patients (n = 25) compared with healthy controls (n = 50). 3T MRI acquisitions included high resolution 3D T1, EPI sequences for diffusion tensor imaging (DTI) as an indirect measure of tissue integrity, and T2*-weighted gradient echo-planar imaging for MR-based relaxometry (R2*), which provides an indirect measure of ferritin/iron deposition in the brain. Myelin breakdown starts in the PreHD stage, but there is no difference in iron content values. Iron content reduction manifests later, in the early HD stage, in which we found a lower R2* parameter value in the isthmus. The WM iron reduction in HD is temporally well-defined (no iron differences in PreHD subjects and iron differences only in early HD patients). Iron level in callosal WM may be regarded as a marker of disease state, as iron does not differentiate PreHD subjects from controls but distinguishes between PreHD and HD.


Assuntos
Corpo Caloso/metabolismo , Doença de Huntington/patologia , Ferro/metabolismo , Bainha de Mielina/patologia , Adulto , Feminino , Humanos , Doença de Huntington/metabolismo , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica
14.
Nanotechnology ; 25(43): 435203, 2014 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-25297338

RESUMO

The growth of ordered arrays of InGaN/GaN nanocolumnar light emitting diodes by molecular beam epitaxy, emitting in the blue (441 nm), green (502 nm), and yellow (568 nm) spectral range is reported. The device active region, consisting of a nanocolumnar InGaN section of nominally constant composition and 250 to 500 nm length, is free of extended defects, which is in strong contrast to InGaN (planar) layers of similar composition and thickness. Electroluminescence spectra show a very small blue shift with increasing current (almost negligible in the yellow device) and line widths slightly broader than those of state-of-the-art InGaN quantum wells.

15.
Br J Cancer ; 109(6): 1570-8, 2013 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-23942071

RESUMO

BACKGROUND: Antibody drug conjugates (ADCs) and immunotoxins (ITs) are promising anticancer immunotherapeutics. Despite their encouraging performance in clinical trials, both ADCs and ITs often suffer from disadvantages such as stoichiometrically undefined chemical linkage of the cytotoxic payload (ADCs) and the potential immunogenicity of toxins derived from bacteria and plants (ITs). METHODS: Human microtubule-associated protein tau (MAP) was cloned in-frame with human EGF, expressed in E. coli and purified by standard chromatographic methods. The in vitro activity was confirmed by flow cytometry, cell viability assays and tubulin polymerisation assay. The in vivo efficacy was demonstrated using noninvasive far-red in vivo imaging. RESULTS: The EGF-MAP selectively induced apoptosis in EGFR-overexpressing proliferating cancer cells through stabilisation of microtubules. Nonproliferating cells were not affected, demonstrating superior selectivity of EGF-MAP for cancer cells. The EGF-MAP was well tolerated at high doses in mice compared with the ETA'-based control. The in vivo efficacy of EGF-MAP was demonstrated in a tumour xenograft mouse model. CONCLUSION: Our data indicate the general mechanism of action for a new class of human immunotherapeutic reagents suitable for the treatment of cancer. This approach combines the binding specificity of targeting ligands with the selective cytotoxicity of MAP towards proliferating cells.


Assuntos
Fator de Crescimento Epidérmico/farmacologia , Proteínas Recombinantes de Fusão/farmacologia , Proteínas tau/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Fator de Crescimento Epidérmico/biossíntese , Fator de Crescimento Epidérmico/química , Fator de Crescimento Epidérmico/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Aleatória , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Transfecção , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas tau/biossíntese , Proteínas tau/química , Proteínas tau/genética
16.
Analyst ; 138(12): 3512-21, 2013 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-23666341

RESUMO

A Differential Mobility Analyser (DMA) is a specific configuration of an Ion Mobility Spectrometer (IMS) where ions with different electrical mobilities are separated in space, instead of in time of drift, as in classical drift-time IMS. This work presents results obtained with a parallel plate DMA instrument, with crucial differences in the sheath flow and the detection system when compared to other instruments in the market. These differences improve the resolving powers and sensitivities of the instrument. Additionally, datasets from IMS or DMA instruments are typically processed with univariate techniques when only qualitative detection is of interest. However, good performance in quantitative measurements can be achieved using multivariate data processing. This work presents for the first time, measurements with a stand-alone DMA instrument and the multivariate data processing related to VOCs and environmentally interesting samples.

17.
J Mater Sci Mater Med ; 24(1): 37-51, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23073838

RESUMO

Bioactive PEO coating on titanium with high Ca/P ratio was fabricated and characterized with respect to its morphology, composition and microstructure. Long-term electrochemical stability of the coating and Ti(4+) ion release was evaluated in artificial saliva. Influence of the lactic acid and fluoride ions on corrosion protection mechanism of the coated titanium was assessed using AC and DC electrochemical tests. The PEO-treated titanium maintained high passivity in the broad range of potentials up to 2.5 V (Ag/AgCl) for up to 8 weeks of immersion in unmodified saliva and exhibited Ti(4+) ion release <0.002 µg cm(-2) days(-1). The high corrosion resistance of the coating is determined by diffusion of reacting species through the coating and resistance of the inner dense part of the coating adjacent to the substrate. Acidification of saliva in the absence of fluoride ions does not affect the surface passivity, but the presence of 0.1 % of fluoride ions at pH ≤4.0 causes loss of adhesion of the coating due to inwards migration of fluoride ions and their adsorption at the substrate/coating interface in the presence of polarisation.


Assuntos
Eletrólise , Gases em Plasma , Saliva , Titânio/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Oxirredução , Espectrometria por Raios X , Propriedades de Superfície , Difração de Raios X
18.
Nano Lett ; 12(6): 2846-51, 2012 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-22591200

RESUMO

The performance of ferroelectric devices is intimately entwined with the structure and dynamics of ferroelectric domains. In ultrathin ferroelectrics, ordered nanodomains arise naturally in response to the presence of a depolarizing field and give rise to highly inhomogeneous polarization and structural profiles. Ferroelectric superlattices offer a unique way of engineering the desired nanodomain structure by modifying the strength of the electrostatic interactions between different ferroelectric layers. Through a combination of X-ray diffraction, transmission electron microscopy, and first-principles calculations, the electrostatic coupling between ferroelectric layers is studied, revealing the existence of interfacial layers of reduced tetragonality attributed to inhomogeneous strain and polarization profiles associated with the domain structure.


Assuntos
Campos Magnéticos , Modelos Químicos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Eletricidade Estática , Simulação por Computador , Condutividade Elétrica , Tamanho da Partícula , Propriedades de Superfície
19.
Eur Respir J ; 39(1): 141-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21659414

RESUMO

The pathogenesis of idiopathic pulmonary fibrosis (IPF) is probably the result of interplay between cytokines/chemokines and growth factors. The renin-angiotensin (Ang) system is involved, although its profibrotic effect is attributed to Ang II. However, recent studies suggest that renin, through a specific receptor, is implicated in fibrogenesis. In this study, the expression of renin and renin receptor was examined in normal and IPF lungs and fibroblasts. Normal human lung fibroblasts were stimulated with renin or transfected with renin small interfering RNA (siRNA), and the expression of transforming growth factor (TGF)-ß1 and α-1-type I collagen was analysed. Normal lungs and lung fibroblasts expressed renin, which was strongly upregulated in IPF lungs and fibroblasts (∼10-fold increase; p<0.05). Immunocytochemistry showed intense renin staining in IPF fibroblasts. Renin-stimulated lung fibroblasts displayed an increase in the expression of TGF-ß1 (mean ± sd 1.8 × 10(3) ± 0.2 × 10(3) versus 1.2 × 10(3)± 0.3 × 10(3) mRNA copies per 18S ribosomal RNA; p<0.01) and collagen (5.93 × 10(2)± 0.66 × 10(2) versus 3.28 × 10(2) ± 0.5 × 10(2); p<0.01), while knocking down renin expression using siRNA provoked a strong decrease of both molecules. These effects were independent of Ang II, since neither losartan nor captopril decreased these effects. Renin also decreased matrix metalloprotease-1 expression and induced TGF-ß1 activation (163 ± 34 versus 110 ± 15 pg active TGF-ß1 per mg total protein). These findings highlight the possible role of renin as an Ang II-independent profibrotic factor in lung fibrosis.


Assuntos
Angiotensinas/metabolismo , Pulmão/metabolismo , Fibrose Pulmonar/metabolismo , Renina/sangue , Células Cultivadas/citologia , Colágeno/metabolismo , Fibroblastos/citologia , Fibrose , Regulação da Expressão Gênica , Humanos , Metaloproteinase 2 da Matriz/metabolismo , RNA Interferente Pequeno/metabolismo , Proteínas Recombinantes/metabolismo , Renina/biossíntese , Sistema Renina-Angiotensina , Fator de Crescimento Transformador beta1/metabolismo
20.
Eur Respir J ; 39(3): 604-10, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21737555

RESUMO

The A/H1N1 influenza strain isolated in Mexico in 2009 caused severe pulmonary illness in a small number of exposed individuals. Our objective was to determine the influence of genetic factors on their susceptibility. We carried out a case-control association study genotyping 91 patients with confirmed severe pneumonia from A/H1N1 infection and 98 exposed but asymptomatic household contacts, using the HumanCVD BeadChip (Illumina, San Diego, CA, USA). Four risk single-nucleotide polymorphisms were significantly (p<0.0001) associated with severe pneumonia: rs1801274 (Fc fragment of immunoglobulin G, low-affinity IIA, receptor (FCGR2A) gene, chromosome 1; OR 2.68, 95% CI 1.69-4.25); rs9856661 (gene unknown, chromosome 3; OR 2.62, 95% CI 1.64-4.18); rs8070740 (RPA interacting protein (RPAIN) gene, chromosome 17; OR 2.67, 95% CI 1.63-4.39); and rs3786054 (complement component 1, q subcomponent binding protein (C1QBP) gene, chromosome 17; OR 3.13, 95% CI 1.89-5.17). All SNP associations remained significant after adjustment for sex and comorbidities. The SNPs on chromosome 17 were in linkage disequilibrium. These findings revealed that gene polymorphisms located in chromosomes 1 and 17 might influence susceptibility to development of severe pneumonia in A/H1N1 infection. Two of these SNPs are mapped within genes (FCGR2A, C1QBP) involved in the handling of immune complexes and complement activation, respectively, suggesting that these genes may confer risk due to increased activation of host immunity.


Assuntos
Variação Genética , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/genética , Pneumonia Viral/genética , Adulto , Proteínas de Transporte/genética , Estudos de Casos e Controles , Cromossomos Humanos Par 1 , Cromossomos Humanos Par 17 , Feminino , Predisposição Genética para Doença , Humanos , Influenza Humana/imunologia , Desequilíbrio de Ligação , Masculino , México , Pessoa de Meia-Idade , Proteínas Mitocondriais/genética , Pneumonia Viral/imunologia , Polimorfismo de Nucleotídeo Único , Receptores de IgG/genética , Índice de Gravidade de Doença , Adulto Jovem
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