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1.
Analyst ; 144(13): 4066-4072, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31165125

RESUMO

Neural stem and progenitor cells (NSPCs) are an extremely important group of cells that form the central nervous system during development and have the potential to repair damage in conditions such as stroke impairment, spinal cord injury and Parkinson's disease degradation. Current schemes for separation of NSPCs are inadequate due to the complexity and diversity of cells in the population and lack sufficient markers to distinguish diverse cell types. This study presents an unbiased high-resolution separation and characterization of NSPC subpopulations using direct current insulator-based dielectrophoresis (DC-iDEP). The properties of the cells were identified by the ratio of electrokinetic (EK) to dielectrophoretic (DEP) mobilities. The ratio factor of NSPCs showed more heterogeneity variance (SD = 3.4-3.9) than the controlled more homogeneous human embryonic kidney cells (SD = 1.1), supporting the presence of distinct subpopulations of cells in NSPC cultures. This measure reflected NSPC fate potential since the ratio factor distribution of more neurogenic populations of NSPCs was distinct from the distribution of astrogenic NSPC populations (confidence level >99.9%). The abundance of NSPCs captured with different ranges of ratio of EK to DEP mobilities also exhibit final fate trends consistent with established final fates of the chosen samples. DC-iDEP is a novel, label-free and non-destructive method for differentiating and characterizing, and potentially separating, neural stem cell subpopulations that differ in fate.

2.
Bioanalysis ; 11(12): 1139-1155, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31179719

RESUMO

Aim: The complications that arise when performing meta-analysis of datasets from multiple metabolomics studies are addressed with computational methods that ensure data quality, completeness of metadata and accurate interpretation across studies. Results & methodology: This paper presents an integrated system of quality control (QC) methods to assess metabolomics results by evaluating the data acquisition strategies and metabolite identification process when integrating datasets for meta-analysis. An ontology knowledge base and a rule-based system representing the experiment and chemical background information direct the processes involved in data integration and QC verification. A diabetes meta-analysis study using these QC methods finds putative biomarkers that differ between cohorts. Conclusion: The methods presented here ensure the validity of meta-analysis when integrating data from different metabolic profiling studies.


Assuntos
Ontologias Biológicas , Análise de Dados , Metabolômica/métodos , Diabetes Mellitus/metabolismo , Humanos , Controle de Qualidade
3.
Psychol Rev ; 125(1): 117-130, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29345482

RESUMO

The optimal strategy in detection theory is to partition the decision axis at a criterion C, labeling all events that score above C "Signal", and all those that fall below "Noise." The optimal position of C, C*, depends on signal probability and payoffs. If observers place their criterion at some place other than C*, they suffer a loss in the Expected Value (EV) of payoffs over the course of many decisions. We provide an explicit equation for the degree of loss, where it is shown that the falloff in value will be steep in contexts of good discrimination and will be a flatter gradient in contexts of poor discrimination. It is these gradients of loss in EV that, in theory, drive C toward C*, strongly when discrimination is good, weakly when discrimination is poor. When signal probabilities or distributions variances are unequal, the basins of attraction are asymmetric, so that dynamic adjustments in C will be asymmetric, and thus, as we show, will leave it biased. We address our analysis to acquisition speed, response variability, discrimination reversal and other aspects of discriminated performance. In the final section, we develop an error correction model that predicts empirically observed deviations from C* that are inconsistent with the standard model, but follow from the proposed model given knowledge of d'. (PsycINFO Database Record


Assuntos
Tomada de Decisões/fisiologia , Modelos Psicológicos , Percepção/fisiologia , Detecção de Sinal Psicológico/fisiologia , Humanos
4.
Am J Community Psychol ; 56(1-2): 25-35, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26066568

RESUMO

Youth partnerships are a promising but understudied strategy for prevention and health promotion. Specifically, little is known about how the functioning of youth partnerships differs from that of adult partnerships. Accordingly, this study compared the functioning of youth partnerships with that of adult partnerships. Several aspects of partnership functioning, including leadership, task focus, cohesion, participation costs and benefits, and community support, were examined. Standardized partnership functioning surveys were administered to participants in three smoke-free youth coalitions (n = 44; 45 % female; 43 % non-Hispanic white; mean age = 13) and in 53 Communities That Care adult coalitions (n = 673; 69 % female; 88 % non-Hispanic white; mean age = 49). Multilevel regression analyses showed that most aspects of partnership functioning did not differ significantly between youth and adult partnerships. These findings are encouraging given the success of the adult partnerships in reducing community-level rates of substance use and delinquency. Although youth partnership functioning appears to be strong enough to support effective prevention strategies, youth partnerships faced substantially more participation difficulties than adult partnerships. Strategies that youth partnerships can use to manage these challenges, such as creative scheduling and increasing opportunities for youth to help others directly, are discussed.


Assuntos
Comportamento Cooperativo , Crime/prevenção & controle , Promoção da Saúde/organização & administração , Prevenção do Hábito de Fumar , Transtornos Relacionados ao Uso de Substâncias/prevenção & controle , Adolescente , Criança , Participação da Comunidade , Feminino , Humanos , Liderança , Masculino , Pessoa de Meia-Idade , Análise Multinível , Análise de Regressão , Inquéritos e Questionários
5.
Psychol Sci ; 25(1): 198-206, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24264940

RESUMO

How might religion shape intergroup conflict? We tested whether religious infusion-the extent to which religious rituals and discourse permeate the everyday activities of groups and their members-moderated the effects of two factors known to increase intergroup conflict: competition for limited resources and incompatibility of values held by potentially conflicting groups. We used data from the Global Group Relations Project to investigate 194 groups (e.g., ethnic, religious, national) at 97 sites around the world. When religion was infused in group life, groups were especially prejudiced against those groups that held incompatible values, and they were likely to discriminate against such groups. Moreover, whereas disadvantaged groups with low levels of religious infusion typically avoided directing aggression against their resource-rich and powerful counterparts, disadvantaged groups with high levels of religious infusion directed significant aggression against them-despite the significant tangible costs to the disadvantaged groups potentially posed by enacting such aggression. This research suggests mechanisms through which religion may increase intergroup conflict and introduces an innovative method for performing nuanced, cross-societal research.


Assuntos
Conflito Psicológico , Comparação Transcultural , Processos Grupais , Religião e Psicologia , Humanos
6.
Anal Bioanal Chem ; 405(1): 351-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23092966

RESUMO

A substantial portion of the atmospheric particle budget is of biological origin (human and animal dander, plant and insect debris, etc.). These bioaerosols can be considered information-rich packets of biochemical data specific to the organism of origin. In this study, bioaerosol samples from various indoor environments were analyzed to create identifiable patterns attributable to a source level of occupation. Air samples were collected from environments representative of human high-traffic- and low-traffic indoor spaces along with direct human skin sampling. In all settings, total suspended particulate matter was collected and the total aerosol protein concentration ranged from 0.03 to 1.2 µg/m(3). High performance liquid chromatography was chosen as a standard analysis technique for the examination of aqueous aerosol extracts to distinguish signatures of occupation compared to environmental background. The results of this study suggest that bioaerosol "fingerprinting" is possible with the two test environments being distinguishable at a 97% confidence interval.


Assuntos
Aerossóis/química , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Cromatografia Líquida de Alta Pressão/métodos , Monitoramento Ambiental/métodos , Desenho de Equipamento , Humanos , Tamanho da Partícula , Material Particulado/análise , Proteínas/análise , Pele/patologia , Fatores de Tempo
7.
Anal Bioanal Chem ; 403(1): 15-26, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22311424

RESUMO

The purpose of this review is to investigate the feasibility of bioaerosol fingerprinting based on current understanding of cellular debris (with emphasis on human-emitted particulates) in aerosols and arguments regarding sampling, sensitivity, separations, and detection schemes. Target aerosol particles include cellular material and proteins emitted by humans, animals, and plants and can be regarded as information-rich packets that carry biochemical information specific to the living organisms present where the sample is collected. In this work we discuss sampling and analysis techniques that can be integrated with molecular (e.g. protein)-detection procedures to properly assess the aerosolized cellular material of interest. Developing a detailed understanding of bioaerosol molecular profiles in different environments suggests exciting possibilities of bioaerosol analysis with applications ranging from military defense to medical diagnosis and wildlife identification.


Assuntos
Aerossóis , Estudos de Viabilidade , Humanos
8.
Electrophoresis ; 32(17): 2292-7, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21823129

RESUMO

Insulator-based dielectrophoresis (iDEP) is a powerful tool for separating and characterizing particles, yet it is limited by a lack of quantitative characterizations. Here, this limitation is addressed by employing a method capable of quantifying the DEP mobility of particles. Using streak-based velocimetry the particle properties are deduced from their motion in a microfluidic channel with a constant electric field gradient. From this approach, the DEP mobility of 1 µm polystyrene particles was found to be -2±0.4 10(-8) cm4 /(V2 s). In the future, such quantitative treatment will allow for the elucidation of unique insights and rational design of devices.


Assuntos
Eletroforese/instrumentação , Eletroforese/métodos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Simulação por Computador , Desenho de Equipamento , Modelos Lineares , Microesferas , Reologia
9.
Electrophoresis ; 31(22): 3634-41, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21077235

RESUMO

Here we present a scheme to separate particles according to their characteristic physical properties, including size, charge, polarizability, deformability, surface charge mobility, dielectric features, and local capacitance. Separation is accomplished using a microdevice based on direct current insulator gradient dielectrophoresis that can isolate and concentrate multiple analytes simultaneously at different positions. The device is dependent upon dielectrophoretic and electrokinetic forces incorporating a global longitudinal direct current field as well as using shaped insulating features within the channel to induce local gradients. This design allows for the production of strong local field gradients along a global field causing particles to enter, initially transported through the channel by electrophoresis and electroosmosis (electrokinetics), and to be isolated via repulsive dielectrophoretic forces that are proportional to an exponent of the field gradient. Sulfate-capped polystyrene nano and microparticles (20, 200 nm, and 1 µm) were used as probes to demonstrate the influence of channel geometry and applied longitudinal field on separation behavior. These results are consistent with models using similar channel geometry and indicate that specific particulate species can be isolated within a distinct portion of the device, whereas concentrating particles by factors from 10(3) to 10(6).


Assuntos
Eletroforese/instrumentação , Eletroforese/métodos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Modelos Químicos , Eletro-Osmose/instrumentação , Eletro-Osmose/métodos , Microesferas , Nanopartículas , Tamanho da Partícula , Poliestirenos/química , Propriedades de Superfície
10.
Dalton Trans ; (33): 4442-50, 2008 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-18698447

RESUMO

The reaction of [Li(THF)(4)][1,8-mu-(Mes(2)B)C(10)H(6)] with HgCl(2) affords [1,1'-(Hg)-[8-(Mes(2)B)C(10)H(6)](2)] () or [1-(ClHg)-8-(Mes(2)B)C(10)H(6)] (), depending on the stoichiometry of the reagents. These two new compounds have been characterized by (1)H, (13)C, (11)B and (199)Hg NMR, elemental analysis and X-ray crystallography. The cyclic voltammogram of in THF shows two distinct waves observed at E(1/2) -2.31 V and -2.61 V, corresponding to the sequential reductions of the two boron centers. Fluoride titration experiments monitored by electrochemistry suggest that binds tightly to one fluoride anion and more loosely to a second one. Theses conclusions have been confirmed by a UV-vis titration experiment which indicates that the first fluoride binding constant (K(1)) is greater than 10(8) M(-1) while the second (K(2)) equals 5.2 (+/- 0.4) x 10(3) M(-1). The fluoride binding properties of have been compared to those of [1-(Me(2)B)-8-(Mes(2)B)C(10)H(6)] () and [1-((2,6-Me(2)-4-Me(2)NC(6)H(2))Hg)-8-(Mes(2)B)C(10)H(6)] (). Both experimental and computational results indicate that its affinity for fluoride anions is comparable to that of but significantly lower than that of the diborane . In particular, the fluoride binding constants of , and in chloroform are respectively equal to 5.0 (+/- 0.2) x 10(5) M(-1), 1.0 (+/- 0.2) x 10(3) M(-1) and 1.7 (+/- 0.1) x 10(3) M(-1). Determination of the crystal structures of the fluoride adducts [S(NMe(2))(3)][-mu(2)-F] and [S(NMe(2))(3)][-mu(2)-F] along with computational results indicate that the higher fluoride binding constant of arises from a strong chelate effect involving two fluorophilic boron centers.


Assuntos
Boro/química , Fluoretos/química , Mercúrio/química , Compostos Organometálicos/química , Boranos/química , Eletroquímica , Concentração de Íons de Hidrogênio , Modelos Moleculares , Conformação Molecular , Compostos Organometálicos/síntese química , Teoria Quântica , Análise Espectral
11.
J Am Chem Soc ; 130(20): 6332-3, 2008 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-18433123

RESUMO

Reaction of bis(pentafluorophenyl)mercury (1) with the Pd(II) complexes [Pd(salophen)] (I, salophen = N,N'-disalicylidene-o-phenylenediaminate) and [Pd(N--C)(OAc)]2 (II, N--C = (2-(2-pyridyl)phenyl-C,N)) leads to the formation of the supramolecular complexes [1-(I)2] and [1-(II)2] in which the mercury synthon is sandwiched by two molecules of the palladium complex. These complexes, whose formation can be observed in solution by UV-vis spectroscopy, have been fully characterized. The short Hg-Pd distances of 3.2841(2) A in [1-(I)2] and 3.1065(8) A in [1-(II)2] indicate the presence of a Hg-Pd metallophilic interaction which, at least for [1-(II)2], is complemented by a Pd(II)-->Hg(II) donor-or component.

12.
Dalton Trans ; (39): 4654-6, 2006 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-17028672

RESUMO

Both pentafluorophenylmercury chloride and trimeric perfluoro-ortho-phenylene mercury interact with phenanthrene to form phosphorescent adducts which exhibit extended binary stacks in the solid state.

14.
Nonlinearity ; 13(6): 1889-1903, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19266058

RESUMO

This paper considers properties of a Markov chain on the natural numbers which models a binary adding machine in which there a non-zero probability of failure each time a register attempts to increment the succeeding register and resets. This chain has a family of natural quotient Markov chains, and extends naturally to a chain on the 2-adic integers. The transition operators of these chains have a self-similar structure, and have a spectrum which is, variously, the Julia set or filled Julia set of a quadratic map of the complex plane.

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