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1.
J Immunol ; 206(8): 1806-1816, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33811104

RESUMO

CD4+ T cells enable the critical B cell humoral immune protection afforded by most effective vaccines. We and others have recently identified an alternative source of help for B cells in mice, invariant NK T (iNKT) cells. iNKT cells are innate glycolipid-specific T cells restricted to the nonpolymorphic Ag-presenting molecule CD1d. As such, iNKT cells respond to glycolipids equally well in all people, making them an appealing adjuvant for universal vaccines. We tested the potential for the iNKT glycolipid agonist, α-galactosylceramide (αGC), to serve as an adjuvant for a known human protective epitope by creating a nanoparticle that delivers αGC plus antigenic polysaccharides from Streptococcus pneumoniae αGC-embedded nanoparticles activate murine iNKT cells and B cells in vitro and in vivo, facilitate significant dose sparing, and avoid iNKT anergy. Nanoparticles containing αGC plus S. pneumoniae polysaccharides elicits robust IgM and IgG in vivo and protect mice against lethal systemic S. pneumoniae However, codelivery of αGC via nanoparticles actually eliminated Ab protection elicited by a T-independent S. pneumoniae vaccine. This is consistent with previous studies demonstrating iNKT cell help for B cells following acute activation, but negative regulation of B cells during chronic inflammation. αGC-containing nanoparticles represent a viable platform for broadly efficacious vaccines against deadly human pathogens, but their potential for eliminating B cells under certain conditions suggests further clarity on iNKT cell interactions with B cells is warranted.


Assuntos
Linfócitos B/imunologia , Galactosilceramidas/metabolismo , Nanopartículas/metabolismo , Células T Matadoras Naturais/imunologia , Infecções Pneumocócicas/imunologia , Polissacarídeos Bacterianos/metabolismo , Vacinas Estreptocócicas/imunologia , Streptococcus pneumoniae/imunologia , Animais , Células Cultivadas , Galactosilceramidas/imunologia , Humanos , Imunidade Humoral , Imunoglobulina G/metabolismo , Imunoglobulina M/metabolismo , Ativação Linfocitária , Camundongos , Polissacarídeos Bacterianos/imunologia , Linfócitos T/imunologia
2.
Nanomedicine ; 13(3): 1095-1103, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27793789

RESUMO

Selenoproteins play an important role in the human body by accomplishing essential biological functions like oxido-reductions, antioxidant defense, thyroid hormone metabolism and immune response; therefore, the possibility to synthesize selenium nanoparticles free of any contaminants is exciting for future nano-medical applications. This paper reports the first synthesis of selenium nanoparticles by femtosecond pulsed laser ablation in de-ionized water. Those pure nanoparticles have been successfully used to inhibit the formation of Candida albicans biofilms. Advanced electron microscopy images showed that selenium nanoparticles easily adhere on the biofilm, then penetrate into the pathogen, and consequently damage the cell structure by substituting with sulfur. 50% inhibition of Candida albicans biofilm was obtained at only 25 ppm. Finally, the two physical parameters proved to affect strongly the viability of Candida albicans are the crystallinity and particle size.


Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candidíase/prevenção & controle , Nanopartículas/química , Nanotecnologia/métodos , Selênio/farmacologia , Antifúngicos/química , Humanos , Lasers , Nanopartículas/ultraestrutura , Nanotecnologia/instrumentação , Selênio/química
3.
J Int Neuropsychol Soc ; 21(1): 74-84, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26304057

RESUMO

Children with fetal alcohol spectrum disorders (FASD) show sociobehavioral impairments; however, the social cognitive profile contributing to these impairments is poorly understood. This study compared social perspective taking and empathy in children with FASD versus typically developing controls (TDC). Thirty-seven children with FASD and 21 TDC participated. Measures included parent-rated CBCL and SSIS, and NEPSY-II Theory of Mind, Test of Social Cognition and Index of Empathy. Parents rated the FASD group higher than TDC on indices of behavior problems and lower on indices of social skills and empathy. Children with FASD scored significantly below TDC on tasks requiring complex social cognition. The majority of correlations between social cognition and parent-ratings were not significant in FASD and TDC, with the exception of a negative correlation between self-reported empathy and parent-rated behavior difficulties in TDC. FASD subgroup analyses revealed lower theory of mind and empathy scores among children with ARND than pFAS/FAS. With regard to sex, males with FASD were rated as having more behavior difficulties than females, whereas TDC females obtained higher empathy ratings than males. In both groups, females scored higher on theory of mind and empathy indices. On theory of mind tasks, older children with FASD performed below younger, whereas younger TDC children performed more poorly than older. Children with FASD show reduced functioning on indices of sociobehavioral and social cognition, and the effects are influenced by sex and age. These findings provide insight into the clinical and social profile of children with FASD.


Assuntos
Empatia/fisiologia , Transtornos do Espectro Alcoólico Fetal/fisiopatologia , Transtornos do Espectro Alcoólico Fetal/psicologia , Habilidades Sociais , Teoria da Mente/fisiologia , Análise de Variância , Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Criança , Feminino , Humanos , Masculino , Pais/psicologia , Estudos Retrospectivos , Inquéritos e Questionários
4.
Nanoscale ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38826113

RESUMO

There is ongoing interest in the rapid, reproducible production of 2-dimensional (2-D) transition metal dichalcogenides (TMD), such as molybdenum-based TMD (MoX2), where X is a chalcogen atom such as sulphur (S), selenium (Se) or tellurium (Te), driven by their unique optical and electronic properties. Once fabricated into an atomically thin layer structure, these materials have a direct-indirect bandgap transition, strong spin-orbit coupling, and favourable electronic and mechanical strain-dependent properties which are attractive for electronics. Pulsed laser ablation in liquid (PLAL) is an economic, green alternative for synthesis of TMD. It has been shown that in the case of MoX2, the chemical processes during the plasma phase of the ablation can yield the formation of multispecies, including MoOx quantum dots when oxygen-containing solvents are used. Here, we introduce the formation of MoSe2 nanoscrolls with low oxygen content synthesized via pulsed laser ablation in deep eutectic solvents (PLADES). Our results suggest that the synthesis produces a stable colloidal solution of large 2-D structures with tuneable surface charge by replacing the deep eutectic solvent (DES) with DI water. Nuclear Magnetic Resonance (NMR) results suggest that irradiating the solvent at near infrared NIR energy does not affect its chemical composition. NMR also proves that serial washing can completely remove solvent from the nanostructures. Raman shifts suggest the formation of large, thin MoSe2 nanosheets aided by the solvent confinement resulting from van der Waal forces and hydrogen bonds interactions between MoSe2 and urea. Binding energies measured by X-ray photoelectron spectroscopy (XPS) confirm MoSe2-DES preference to form 1T-MoSe2versus molybdenum oxides and 2H MoSe2 in DI-water. Raman and XPS findings were validated by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Results of this work validate the use of PLADES for the synthesis of stable, crystalline, low-surface-oxygen-content colloidal MoSe2 nanoscrolls in scalable quantities.

5.
Lasers Med Sci ; 28(6): 1559-66, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23380906

RESUMO

The optical properties of human whole blood and blood plasma with and without Y2O3 and Nd³âº:Y2O3 nanoparticles are characterized in the near infrared region at 808 nm using a double integrating sphere technique. Using experimentally measured quantities of diffuse reflectance and diffuse transmittance, a computational analysis was conducted utilizing the Kubelka-Munk, the Inverse Adding Doubling, and Magic Light Kubelka-Munk and Monte Carlo Methods to determine optical properties of the absorption and scattering coefficients. Room temperature absorption and emission spectra were also acquired of Nd³âº:Y2O3 nanoparticles elucidating their utility as biological markers. The emission spectra of Nd³âº:Y2O3 were taken by exciting the nanoparticles before and after entering the whole blood sample. The emission from the 4F(3/2) → 4I(11/2) manifold transition of Nd³âº:Y2O3 nanoparticles readily propagates through the blood sample at excitation of 808 nm and exhibits a shift in relative intensities of the peaks due to differences in scattering. At 808 nm, in both whole blood and plasma samples, a direct relationship was found with absorption coefficient and Y2O3 nanoparticle concentration. Results for the whole blood indicate a small inverse relationship with Y2O3 nanoparticle concentration and scattering coefficient and in contrast a direct relation for the plasma.


Assuntos
Análise Química do Sangue , Sangue/metabolismo , Nanopartículas Metálicas/química , Humanos , Neodímio/química , Fenômenos Ópticos , Plasma/química , Plasma/metabolismo , Espectrometria de Fluorescência , Espectrofotometria , Espectroscopia de Luz Próxima ao Infravermelho , Ítrio/química
6.
Alcohol Clin Exp Res ; 33(10): 1656-70, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19624575

RESUMO

BACKGROUND: Although children with Fetal Alcohol Spectrum Disorders (FASDs) are at high risk of attention deficit hyperactivity disorder (ADHD), direct comparisons show distinct cognitive phenotypes in the 2 diagnoses. However, these groups have not been directly compared for social problems or social cognition, nor has social cognition been directly examined in FASDs. OBJECTIVES: To compare FASDs and ADHD groups on social cognition tasks and determine whether deficient social cognition and emotion processing predict behavioral problems and social skills. METHODS: Studied were 33 children with FASDs, 30 with ADHD, and 34 normal controls (NC). All received tasks of social cognition and emotion processing. Parents and teachers rated children on measures of completed questionnaires assessing child's behavioral problems and social skills using the Child Behavior Checklist, Teacher Report Form, and Social Skills Rating Scale. Children received 3 subtests from the Saltzman-Benaiah and Lalonde (2007) Theory of Mind Task as a measure of social cognition and 4 subtests from the Minnesota Test of Affective Processing (Lai et al., 1991) to assess emotion processing. RESULTS: Parents and teachers reported more behavior problems and poorer social skills in children in FASD and ADHD than NC groups. FASDs demonstrated significantly weaker social cognition and facial emotion processing ability than ADHD and NC groups. Regression analyses identified social cognition as a significant predictor of behavior problems and emotion processing as a significant predictor of social skills. CONCLUSIONS: Children with FASDs show a distinct behavioral profile from children with ADHD. Difficulties in social cognition and emotion processing in children with FASDs may contribute to their high incidence of social behavioral problems.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Cognição/fisiologia , Emoções/fisiologia , Transtornos do Espectro Alcoólico Fetal/psicologia , Comportamento Social , Adolescente , Criança , Feminino , Humanos , Testes de Inteligência , Masculino , Testes Neuropsicológicos , Gravidez , Escalas de Graduação Psiquiátrica , Análise de Regressão
7.
Ther Drug Monit ; 31(6): 670-82, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19865003

RESUMO

BACKGROUND: Methylmercury is an environmental pollutant that can cause irreversible effects on the development of children. Although there is no doubt that high exposure can cause neurodevelopmental deficits, the threshold that will adversely affect the developing fetus is not well defined. Our objective was to systematically review the evidence of neurodevelopmental risks of methylmercury to the unborn child from maternal fish consumption to define the lowest observable adverse effect hair concentration (LOAEHC). METHODS: A systematic review was conducted of all original research reporting on the effects of methylmercury on the human fetus. A literature search was undertaken using SCOPUS, Medline-Ovid, PubMed, Google Scholar, and EMBASE. Papers were selected based on the following inclusion criteria: 1) child neurodevelopmental outcome; 2) comparison groups; and 3) methylmercury exposure through fish consumption. RESULTS: Forty-eight publications met these inclusion criteria. Thirty articles reported on longitudinal studies and 18 were cross-sectional studies. Variations in study design precluded formal meta-analysis. Based on an evaluation of these studies, we defined the LOAEHC at 0.3 microg/g of maternal hair mercury. The longitudinal studies yielded a LOAEHC of 0.5 microg/g. CONCLUSION: In the clinical context, the majority of pregnant women consume mercury-containing fish in amounts that are lower than the LOAEHC defined in this study. However, the LOAEHC is in the same order of magnitude of mercury exposure that occurs in significant numbers of women. Hence, although it appears safe to suggest that eating the recommended types and amounts of fish poses no measurable risks for neurodevelopmental deficits, analysis of hair mercury content before pregnancy might be suggested because dietary modification can decrease body content and risk.


Assuntos
Contaminação de Alimentos , Cabelo/química , Exposição Materna/efeitos adversos , Intoxicação do Sistema Nervoso por Mercúrio/diagnóstico , Mercúrio/análise , Compostos de Metilmercúrio/toxicidade , Testes de Toxicidade/métodos , Animais , Feminino , Desenvolvimento Fetal/efeitos dos fármacos , Peixes , Humanos , Masculino , Exposição Materna/estatística & dados numéricos , Mercúrio/toxicidade , Intoxicação do Sistema Nervoso por Mercúrio/fisiopatologia , Intoxicação do Sistema Nervoso por Mercúrio/prevenção & controle , Compostos de Metilmercúrio/administração & dosagem , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Alimentos Marinhos/efeitos adversos
8.
J Colloid Interface Sci ; 541: 234-248, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30690267

RESUMO

Different morphologies and crystal phases of black titanium dioxide (TiO2) were synthesized using Pulsed Laser Ablation in Liquid (PLAL). The synthesized laser modified black TiO2 (LMB-TiO2) structures included hydrogenated anatase TiO2 nanoparticles, as the core shell structures, and TiO2 microspheres. TiO2 core-shell nanoparticles, which had crystalline-disordered structures, demonstrated the laser ablation pulse duration-dependence growth of amorphous shells and hence formation of disordered TiO2 nanoparticles with different thickness of hydrogen-doped amorphous shells were shown. TiO2 microspheres with the yolk-shell like structures (YSHL-TiO2 microspheres), on the other hand, showed the formation of rutile phases in the shell which encapsulate Lattice Expanded Planes (LEPs) in the core. The microspheres demonstrated phase transitions from anatase to rutile and size-dependent lattice interlayers expansion from 0.35 nm to 0.94 nm. The maximum particle size growth occurred when the samples were subjected to the laser ablation for 120 min. The crystal phase transition, consequently, led to the formation of heterostructured photocatalysts through construction of hydrogenated anatase TiO2 nanoparticles junctions with rutile TiO2 microspheres. The photocatalytic degradation of methylene blue (MB) using LMB-TiO2 heterostructure was tested under visible light irradiation Results showed approximately 99% of MB was degraded after 60 min. Enhanced visible light absorption and increased charge carrier lifetime due to formation of different types of heterojunctions may explain the higher photocatalytic performance of LM-TiO2 samples. Moreover, the Photoluminescence analysis indicated that hydroxyl radicals were the main active species involved in the photocatalytic degradation tests and therefore the photocatalysis mechanism was accordingly suggested.

9.
J Int Neuropsychol Soc ; 14(6): 1022-33, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18954482

RESUMO

Children with prenatal alcohol exposure (PAE) show deficits in verbal learning and spatial memory, as well as abnormal hippocampal development. The relationship between their memory and neuroanatomic impairments, however, has not been directly explored. Given that the hippocampus is integral for the synthesis and retrieval of learned information and is particularly vulnerable to the teratogenic effects of alcohol, we assessed whether reduced learning and recall abilities in children with fetal alcohol spectrum disorders (FASDs) are associated with abnormal hippocampal volumes. Nineteen children with FASDs and 18 typically developing controls aged 9 to 15 years were assessed for verbal learning and verbal and spatial recall and underwent structural magnetic resonance imaging. Images were analyzed for total intracranial volume and for right and left hippocampal volumes. Results revealed smaller left hippocampi and poorer verbal learning and verbal and spatial recall performance in children with FASDs than controls, as well as positive correlations between selective memory indices and hippocampal volumes only in the FASD group. Additionally, hippocampal volumes increased significantly with age in controls only, suggesting that PAE may be associated with long-term abnormalities in hippocampal development that may contribute to impaired verbal learning and verbal and spatial recall.


Assuntos
Álcoois , Hipocampo/patologia , Rememoração Mental/fisiologia , Efeitos Tardios da Exposição Pré-Natal/patologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Percepção Espacial/fisiologia , Aprendizagem Verbal/fisiologia , Adolescente , Criança , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Testes Neuropsicológicos , Gravidez , Fatores Sexuais
10.
ScientificWorldJournal ; 8: 873-82, 2008 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-18836653

RESUMO

Fetal alcohol spectrum disorders (FASDs) currently represent the leading cause of mental retardation in North America, ahead of Down syndrome and cerebral palsy. The damaging effects of alcohol on the developing brain have a cascading impact on the social and neurocognitive profiles of affected individuals. Researchers investigating the profiles of children with FASDs have found impairments in learning and memory, executive functioning, and language, as well as hyperactivity, impulsivity, poor communication skills, difficulties with social and moral reasoning, and psychopathology. The primary goal of this review paper is to examine current issues pertaining to the identification of a behavioral phenotype in FASDs, as well as to address related screening and diagnostic concerns. We conclude that future research initiatives comparing children with FASDs to nonalcohol-exposed children with similar cognitive and socioemotional profiles should aid in uncovering the unique behavioral phenotype for FASDs.


Assuntos
Sintomas Comportamentais/etiologia , Transtornos do Espectro Alcoólico Fetal/psicologia , Atenção , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Criança , Transtornos Cognitivos/diagnóstico , Emoções , Feminino , Transtornos do Espectro Alcoólico Fetal/diagnóstico , Humanos , Transtornos do Desenvolvimento da Linguagem/etiologia , Aprendizagem , Memória , Fenótipo , Gravidez
11.
Int J Nanomedicine ; 13: 2697-2708, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29760550

RESUMO

BACKGROUND: Candida albicans is a major opportunistic fungal pathogen. One of the most important virulence factors that contribute to the pathogenesis of candidiasis is its ability to form biofilms. A key characteristic of Candida biofilms is their resistance to antifungal agents. Due to significant morbidity and mortality rates related to biofilm-associated drug resistance, there is an urgency to develop novel nanotechnology-based approaches preventing biofilm-related infections. METHODS: In this study, we report, for the first time, the synthesis of selenium nanoparticles by irradiating selenium pellets by nanosecond pulsed laser ablation in liquid chitosan as a capping agent. Synergy of the fungicidal effect of selenium nanoparticles and chitosan was quantified by the combination index theorem of Chou-Talalay. RESULTS: This drug combination resulted in a potent fungicidal effect against a preformed C. albicans biofilm in a dose-response manner. By advanced electron microscopy techniques, we documented the adhesive and permeabilizing properties of chitosan, therefore allowing selenium nanoparticles to enter as the cell wall of the yeast became disrupted and distorted. Most importantly, we demonstrated a potent quantitative synergistic effect when compounds such as selenium and chitosan are combined. CONCLUSION: These chitosan-stabilized selenium nanoparticles could be used for ex vivo applications such as sterilizers for surfaces and biomedical devices.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Nanopartículas/química , Antifúngicos/síntese química , Candida albicans/patogenicidade , Candida albicans/fisiologia , Linhagem Celular , Quitosana/química , Quitosana/farmacologia , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Humanos , Lasers , Testes de Sensibilidade Microbiana , Nanopartículas/administração & dosagem , Nanopartículas/toxicidade , Nanotecnologia/métodos , Selênio/química , Selênio/farmacologia
12.
Neurosci Biobehav Rev ; 31(2): 254-60, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-16934870

RESUMO

The diagnosis of fetal alcohol spectrum disorder is a difficult task, especially in cases where clear, physical markers of in utero alcohol exposure are not apparent. Reviewed in the following paper are some older tools for screening alcohol use in pregnancy and present novel approaches to the diagnosis of FASD, including ethanol biomarker development to behavioural phenotyping. Improving current FASD diagnostic methodology through more novel approaches may provide the possibility of earlier and wider diagnosis, allowing intervention and treatment at stages where the advanced effects of alcohol can still be mitigated.


Assuntos
Transtornos do Espectro Alcoólico Fetal/diagnóstico , Efeitos Tardios da Exposição Pré-Natal/diagnóstico , Álcoois , Sintomas Comportamentais , Biomarcadores , Feminino , Transtornos do Espectro Alcoólico Fetal/fisiopatologia , Cabelo/patologia , Humanos , Masculino , Mecônio/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Inquéritos e Questionários
13.
Brain Sci ; 8(1)2017 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-29283403

RESUMO

Children with fetal alcohol spectrum disorder (FASD) exhibit behavioral dysregulation, executive dysfunction, and atypical function in associated brain regions. Previous research shows early intervention mitigates these outcomes but corresponding brain changes were not studied. Given the Alert® Program for Self-Regulation improves behavioral regulation and executive function in children with FASD, we asked if this therapy also improves their neural functioning in associated regions. Twenty-one children with FASD aged 8-12 years were randomized to the Alert®-treatment (TXT; n = 10) or waitlist-control (WL; n = 11) conditions. They were assessed with a Go-NoGo functional magnetic resonance imaging (fMRI) paradigm before and after training or the wait-out period. Groups initially performed equivalently and showed no fMRI differences. At post-test, TXT outperformed WL on NoGo trials while fMRI in uncorrected results with a small-volume correction showed less activation in prefrontal, temporal, and cingulate regions. Groups also demonstrated different patterns of change over time reflecting reduced signal at post-test in selective prefrontal and parietal regions in TXT and increased in WL. In light of previous evidence indicating TXT at post-test perform similar to non-exposed children on the Go-NoGo fMRI paradigm, our findings suggest Alert® does improve functional integrity in the neural circuitry for behavioral regulation in children with FASD.

14.
Child Neuropsychol ; 23(8): 980-993, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27829119

RESUMO

Although the profile of social cognitive difficulties is well recognized in children with certain neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), this profile is not as well established in other clinical pediatric populations. The objective of the present study is to examine patterns of social perception in children with fetal alcohol spectrum disorder (FASD) compared to typically-developing (TD) control children. A total of 56 children between 8 and 12 years of age-35 with FASD and 21 TD-completed the Reading the Mind in the Eyes Task - Children's Version (RMET-C). The RMET-C accuracy scores were compared between groups and also by item difficulty and emotional valence. The relation between cognitive functioning, age, FASD severity, and RMET-C performance was also investigated. The children in the FASD group did not perform as well as the children in the TD group on the RMET-C Total score and Easy items, as well as the Positive, Negative, and Neutral emotional valence items. When age and IQ were investigated, there was a significant effect of age on the Positive items in the TD group, with scores increasing with age. With regard to FASD severity, children with alcohol-related neurodevelopmental disorder were outperformed by children with full/partial fetal alcohol syndrome on the Positive and Negative items. Overall, these results further the understanding of the social cognitive profile in children with FASD and how this profile relates to other childhood-onset neurodevelopmental disorders.


Assuntos
Transtornos do Espectro Alcoólico Fetal/psicologia , Comportamento Social , Percepção Social , Criança , Humanos , Masculino
15.
J Colloid Interface Sci ; 462: 325-33, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26476201

RESUMO

One major source of complexity in the implementation of nanoparticles in aqueous electrolytes arises from the strong influence that biological environments has on their physicochemical properties. A key parameter for understanding the molecular mechanisms governing the physicochemical properties of nanoparticles is the formation of the surface charge density. In this article, we present an efficient and accurate approach that combines a recently introduced classical solvation density functional theory for spherical electrical double layers with a surface complexation model to account for ion-ion correlation and excluded volume effects on the surface titration of spherical nanoparticles. We apply the proposed computational approach to account for the charge-regulated mechanisms on the surface chemistry of spherical silica (SiO2) nanoparticles. We analyze the effects of the nanoparticle size, as well as pH level and electrolyte concentration of the aqueous solution on the nanoparticle's surface charge density and Zeta potential. We validate our predictions for 580Å and 200Å nanoparticles immersed in acid, neutral and alkaline mono-valent aqueous electrolyte solutions against experimental data. Our results on mono-valent electrolyte show that the excluded volume and ion-ion correlations contribute significantly to the surface charge density and Zeta potential of the nanoparticle at high electrolyte concentration and pH levels, where the solvent crowding effects and electrostatic screening have shown a profound influence on the protonation/deprotonation reactions at the liquid/solute interface. The success of this approach in describing physicochemical properties of silica nanoparticles supports its broader application to study other spherical metal oxide nanoparticles.


Assuntos
Nanopartículas/química , Dióxido de Silício/química , Físico-Química , Eletrólitos/química , Concentração de Íons de Hidrogênio , Íons/química , Tamanho da Partícula , Teoria Quântica , Solventes/química , Propriedades de Superfície
16.
Sci Rep ; 6: 32019, 2016 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-27562291

RESUMO

A magnetically controlled elastically driven electroporation phenomenon, or magneto-elasto-electroporation (MEEP), is discovered while studying the interactions between core-shell magnetoelectric nanoparticles (CSMEN) and biological cells in the presence of an a.c. magnetic field. In this paper we report the effect of MEEP observed via a series of in-vitro experiments using core (CoFe2O4)-shell (BaTiO3) structured magnetoelectric nanoparticles and human epithelial cells (HEP2). The cell electroporation phenomenon and its correlation with the magnetic field modulated CSMEN are described in detail. The potential application of CSMEN in electroporation is confirmed by analyzing crystallographic phases, multiferroic properties of the fabricated CSMEN, influences of d.c. and a.c. magnetic fields on the CSMEN and cytotoxicity tests. The mathematical formalism to quantitatively describe the phenomena is also reported. The reported findings provide insights into the underlying MEEP mechanism and demonstrate the utility of CSMEN as an electric pulse-generating nano-probe in electroporation experiments with a potential application toward accurate and efficient targeted cell permeation.

17.
Biosens Bioelectron ; 64: 676-82, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25441418

RESUMO

In this work, the assembly of gold nanoparticles of (AuNPs) is used to detect the presence of the biomolecule glutathione (GSH) using a novel technique called "all-optical photoacoustic spectroscopy" (AOPAS). The AOPAS technique coupled with AuNPs forms the basis of a biosensing technique capable of probing the dynamic evolution of nano-bio interfaces within a microscopic volume. Dynamic Light Scattering (DLS) and ultraviolet-visible (UV-vis) spectra were measured to describe the kinetics governing the interparticle interactions by monitoring the AuNPs assembly and evolution of the surface plasmon resonance (SPR) band. A comparison of the same dynamic evolution of AuNPs assembly was performed using the AOPAS technique to confirm the validity of this method. The fundamental study is complemented by a demonstration of the performance of this biosensing technique in the presence of cell culture medium containing fetal bovine serum (FBS), which forms a protein corona on the surface of the AuNPs. This work demonstrates that the in vitro monitoring capabilities of the AOPAS provides sensitive measurement at the microscopic level and low nanoparticle concentrations without the artifacts limiting the use of conventional biosensing methods, such as fluorescent indicators. The AOPAS technique not only provides a facile approach for in vitro biosensing, but also shed a light on the real-time detection of thiol containing oxidative stress biomarkers in live systems using AuNPs.


Assuntos
Glutationa/análise , Glutationa/química , Ouro/química , Nanopartículas Metálicas/química , Microquímica/instrumentação , Técnicas Fotoacústicas/instrumentação , Análise Espectral/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Oxirredução
18.
Front Hum Neurosci ; 9: 108, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25788884

RESUMO

Children with fetal alcohol spectrum disorder show executive function (EF) deficits, particularly in self-regulation skills, and abnormalities in brain regions critical for these skills. None of the validated EF interventions for these children has been evaluated with regards to impacts on brain structure. Twenty-nine children with FASD were assigned to either an immediate-treatment (TX) or delayed-treatment control (DTC) group (DTC). Nineteen typically developing children served as healthy controls (CT). All received a structural MRI scan and baseline neuropsychological testing, following which the TX group underwent 12 weekly 1.5-h sessions of the Alert Program for Self-Regulation(®). After treatment or a period of ~14 weeks, all received a repeat scan and post-intervention testing. Whole-brain and region-of-interest analyses using voxel-based morphometry evaluated group differences and changes over time in gray matter (GM). Exploratory analyses revealed significant group changes: (1) At baseline, combined TX and DTC groups demonstrated global GM reductions compared with the CT group. (2) Region-of-interest analysis using a frontal mask, comparing post-intervention to pre-intervention results, showed significantly increased GM in the left middle frontal gyrus (BA10), right frontal pole (BA11), and right anterior cingulate (BA32) in the TX group. Similar results were not found in the DTC or CT groups. (3) At post-intervention, both TX and CT groups showed larger GM volumes than the DTC group in the left superior frontal gyrus (BA9), which was smaller in the FASD group at baseline. These results suggested that Alert led to improvements in post-intervention testing of self-regulation skills and typical brain development in treated children.

19.
Child Neuropsychol ; 21(2): 191-209, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25010354

RESUMO

An extensive body of literature has documented executive function (EF) impairments in children with fetal alcohol spectrum disorders (FASD); however, few studies have aimed specifically at improving EF. One treatment program that shows promise for children with FASD is the Alert Program for Self-Regulation®, which is a 12-week treatment specifically designed to target self-regulation, a component of EF. The present study sought to examine if Alert would produce improvements in self-regulation that would generalize to other aspects of EF, behavior, and social skills in children with FASD. Twenty-five children aged 8-12 years diagnosed with an FASD were assigned in alternating sequence to either an immediate treatment (TXT) or a delayed treatment control (DTC) group. Both groups received a comprehensive evaluation of EF at baseline and upon completing therapy (TXT), or after a 12- to 14-week interval from baseline (DTC). Parents also completed questionnaires assessing EF and behavior at both time points. For the TXT group only, parent questionnaires were readministered at 6-month follow-up. At the 12-week follow-up, the TXT group displayed significant improvements in inhibitory control and social cognition. Parents of children in the TXT group reported improved behavioral and emotional regulation, as well as reduced externalizing behavior problems. These behavioral improvements along with further improved parent-rated inhibitory control was maintained at the 6-month follow-up. The EF disabilities in children with FASD can be remediated through a targeted treatment approach aimed at facilitating self-regulation skills.


Assuntos
Cognição , Terapia Cognitivo-Comportamental , Função Executiva/fisiologia , Transtornos do Espectro Alcoólico Fetal/terapia , Comportamento Social , Adulto , Criança , Emoções , Feminino , Transtornos do Espectro Alcoólico Fetal/fisiopatologia , Seguimentos , Humanos , Masculino , Pais , Gravidez , Avaliação de Programas e Projetos de Saúde , Inquéritos e Questionários , Fatores de Tempo , Resultado do Tratamento
20.
Curr Opin Psychiatry ; 27(2): 98-104, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24445400

RESUMO

PURPOSE OF REVIEW: Since the first description of the foetal damage of alcohol in 1967, numerous studies have outlined different aspects of neurodevelopmental dysfunction, adversely affecting the lives of children worldwide. Although the cause of the syndrome is sorted out, the pathogenesis of brain damage is far from being clear. In contrast to children exhibiting the full facial dysmorphology, who are relatively easy to diagnose, in those presenting only with alcohol-related neurodevelopmental damage diagnosis is much more challenging due to poor specificity of the brain dysfunction. Hence, identifying the neurodevelopmental phenotype of foetal alcohol spectrum disorder (FASD) is a major challenge. RECENT FINDINGS: Recently, a behavioural phenotype of FASD has been described and validated using items from the Child Behaviour Checklist. This tool has high sensitivity and specificity in separating children with FASD from those with ADHD and from healthy controls. In parallel, a number of intervention studies show promise in improving the abilities of children and adolescents with the syndrome to cope with daily tasks and improve their quality of life. SUMMARY: The neurobehavioural screening test can facilitate screening for FASD and is an official screening tool in the FASD toolkit of the Public Health Agency of Canada. Promising new interventions may attenuate the long-term outcome of these children.


Assuntos
Transtornos do Comportamento Infantil/diagnóstico , Transtornos do Espectro Alcoólico Fetal/diagnóstico , Testes Neuropsicológicos , Adolescente , Criança , Transtornos do Comportamento Infantil/psicologia , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/psicologia , Transtornos do Espectro Alcoólico Fetal/psicologia , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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