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1.
Langmuir ; 35(18): 6048-6054, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30991806

RESUMO

We have prepared phosphatidylcholine (PC) vesicles (liposomes) incorporating a novel lipid/poly-phosphocholine conjugate. This both stabilizes the liposomes against aggregation (for example, during storage or when being delivered) and allows them to act as very efficient lubricating elements readily attaining superlubric performance (defined as coefficient of friction µ < 10-2) via hydration lubrication at physiological salt concentrations and pressures. In contrast, vesicles sterically protected by poly(ethylene glycol) chains (PEGylation), which is the general method of choice, while being equally stable to aggregation are much poorer lubricants under these conditions, which is attributed to the relatively poor hydration of the PEG. Our approach enables the use of PC liposomes as stable superlubrication vectors in potential biomedical applications.


Assuntos
Vetores Genéticos/química , Fosfatidilcolinas/química , Polietilenoglicóis/química , Lipossomos
2.
Analyst ; 139(13): 3352-5, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-24835140

RESUMO

A simple fabrication method for preparing lipophilic gold nanoparticles (AuNPs) suitable for use as substrates in surface-enhanced Raman scattering (SERS) applications of lipids was developed. The AuNPs were shown to be dispersible within lipid phases, where they greatly increased the SERS signals of lipids.


Assuntos
Ouro/química , Lipídeos/química , Nanopartículas Metálicas/química , Análise Espectral Raman/métodos , Propriedades de Superfície
3.
Analyst ; 139(20): 5075-8, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25134491

RESUMO

Herein, we fabricated amphiphilic gold nanoparticles (GNPs) that can self-assemble at oil-water interfaces. We applied those GNPs for in situ SERS detection of emulsifier molecules within the interfacial region of oil in water (O/W) emulsion systems.


Assuntos
Técnicas de Química Analítica/métodos , Emulsificantes/análise , Ouro/química , Nanopartículas Metálicas/química , Análise Espectral Raman , Lactoglobulinas/química , Óleos/química , Tamanho da Partícula , Análise de Componente Principal , Água/química
4.
J Food Sci ; 83(5): 1373-1380, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29660814

RESUMO

Previous studies demonstrate humans can detect fatty acids via specialized sensors on the tongue, such as the CD36 receptor. Genetic variation at the common single nucleotide polymorphism rs1761667 of CD36 has been shown to differentially impact the perception of fatty acids, but comparative data among different ethnic groups are lacking. In a small cohort of Caucasian and East Asian young adults, we investigated if: (1) participants could detect oleic acid (C18:1) added to safflower oil emulsions at a constant ratio of 3% (w/v); (2) supplementation of oleic acid to safflower oil emulsions enhanced perception of fattiness and creaminess; and (3) variation at rs1761667 influenced oleic acid detection and fat taste perception. In a 3-alternate forced choice test, 62% of participants detected 2.9 ± 0.7 mM oleic acid (or 0.08% w/v) in a 2.8% safflower oil emulsion. Supplementation of oleic acid did not enhance fattiness and creaminess perception for the cohort as a whole, though East Asians carrying the GG genotype perceived more overall fattiness and creaminess than their AA genotype counterparts (P < 0.001). No differences were observed for the Caucasians. These preliminary findings indicate that free oleic acid can be detected in an oil-in-water emulsion at concentrations found in commercial oils, but it does not increase fattiness or creaminess perception. Additionally, variation at rs1761667 may have ethnic-specific effects on fat taste perception.


Assuntos
Antígenos CD36/genética , Etnicidade , Ácido Oleico/administração & dosagem , Óleo de Cártamo/administração & dosagem , Percepção Gustatória/genética , Adulto , Composição Corporal , Índice de Massa Corporal , Emulsões , Feminino , Aditivos Alimentares/administração & dosagem , Aditivos Alimentares/análise , Frequência do Gene , Humanos , Metabolismo dos Lipídeos , Masculino , Ácido Oleico/análise , Polimorfismo de Nucleotídeo Único , Óleo de Cártamo/química , Paladar , Adulto Jovem
5.
Harv Bus Rev ; 84(2): 110-21, 165, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16485809

RESUMO

Leaders make decisions every day of their lives, but how they do it changes dramatically over the course of their careers. At lower levels, the job is to get widgets out the door; action is at a premium. At higher levels, the job involves decisions about which widgets to offer and how to develop them. To climb the corporate ladder and be effective in new roles, managers need to change the way they use information and evaluate options. Based on a study of the decision-making profiles of more than 120,000 executives, the authors found that people make decisions very differently in public than they do in private and that the decision styles of successful managers evolve in highly predictable patterns. The most successful managers and executives become increasingly open and interactive in their leadership (or public) styles, and more analytic in their thinking (or private) styles, as they progress in their careers. The research shows that decision-making profiles do a complete flip over the course of a career; that is, the decision profile of a successful CEO is the opposite of a successful first-line supervisor's. When does the major change in focus occur? Somewhere between the manager level and the director level, executives find that formerly effective decision styles no longer work so well. At this point, decision styles fall into a "convergence zone", where managers use all styles more or less equally. From then on, the executives continue to evolve their styles. The most successful managers come to the convergence zone quickly and continue to adjust their styles as their careers progress. Low performers seem to stagnate once they hit the convergence zone; their styles do not evolve in new directions. Clearly, relying on past successes and habits is no guarantee of success-indeed, it may be the road to failure.


Assuntos
Pessoal Administrativo , Tomada de Decisões , Comércio/organização & administração , Humanos , Estados Unidos
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