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1.
Cogn Process ; 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38727942

RESUMEN

Despite their widespread use during the COVID-19 pandemic, face masks hinder abilities to interpret facial expressions. Yet, they can also reduce the appearance of characteristics that are used to categorize individuals into racial groups, such as Afrocentric features. The color of a face mask might also promote associations with certain types of behavior and professional occupations (e.g., blue surgical mask connoting physician stereotypes; black masks potentially being associated with criminality). This study assessed whether the presence and color of a face mask impacted perceptions of a target male of varying race. White participants (N = 250) were presented with an African American or White male adult face from the Chicago Face Database (of equal age and attractiveness) wearing a blue or black surgical mask, or no mask (Photoshopped onto the face) and rated the man on emotions (happy, sad, angry) as well as how trustworthy, threatening, and attractive the target appeared. Targets wearing a blue surgical mask were judged as more trustworthy and attractive than those wearing no mask (perhaps due to association with medical professions), but these judgements were not qualified by race, despite the African American target's selection based on Afrocentric features. The color black on a face mask did not exacerbate negative perceptions of targets, perhaps suggesting a decline effect in previously demonstrated associations between this color and criminal actions. Unlike previous research performed at the beginning of the Covid-19 Pandemic on cloth masks shown to potentially exacerbate racial biases, surgical masks (pleated and made of polymeric materials), appear to lessen potential stereotyping of Black relative to White men.

2.
Arch Sex Behav ; 49(2): 769-786, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31598804

RESUMEN

Turner syndrome (TS) is a genetic condition characterized by partial or complete monosomy X. Alterations in hormonal function, height, and peer relationships, among other features and correlates of TS, appear to be risks for depressive illness. In order to summarize what is known about depression in Turner syndrome, with the aim of determining whether individuals with TS are at increased risk for depression, a literature search and analysis were conducted. In total, 69 studies were identified and 35 met criteria of being peer-reviewed English language articles that collected original data on the experience of depression in individuals with TS. Most studies used patient or parent questionnaires to evaluate depressive symptoms. These studies, a majority of which examined adults and half that examined adolescents, found that individuals with TS experienced more frequent and severe depressive symptoms than individuals without TS diagnoses. Articles studying children with TS did not demonstrate a difference in their depressive experience compared to individuals without TS. Three articles used clinician-administered scales, such as the Structured Clinical Interview for DSM-IV; all diagnosed depression in those with TS at higher rates than others. Five studies relied on expert opinion to evaluate depression. The remaining eight articles were case reports or case series that relied on expert opinion. From these data, we conclude that adolescents and adults with TS are at risk for depression and adulthood appears to be the period of the highest risk. Studies in the last 12 years show consistently more severe depressive symptoms in individuals with TS than in previous years. Implications, risk factors, and recommendations for future research are discussed.


Asunto(s)
Depresión/etiología , Síndrome de Turner/complicaciones , Síndrome de Turner/psicología , Femenino , Humanos
3.
J Vis Exp ; (147)2019 05 09.
Artículo en Inglés | MEDLINE | ID: mdl-31132052

RESUMEN

Here, a method to synthesize cellulose nanofiber biotemplated palladium composite aerogels is presented. Noble metal aerogel synthesis methods often result in fragile aerogels with poor shape control. The use of carboxymethylated cellulose nanofibers (CNFs) to form a covalently bonded hydrogel allows for the reduction of metal ions such as palladium on the CNFs with control over both nanostructure and macroscopic aerogel monolith shape after supercritical drying. Crosslinking the carboxymethylated cellulose nanofibers is achieved using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the presence of ethylenediamine. The CNF hydrogels maintain their shape throughout synthesis steps including covalent crosslinking, equilibration with precursor ions, metal reduction with high concentration reducing agent, rinsing in water, ethanol solvent exchange, and CO2 supercritical drying. Varying the precursor palladium ion concentration allows for control over the metal content in the final aerogel composite through a direct ion chemical reduction rather than relying on the relatively slow coalescence of pre-formed nanoparticles used in other sol-gel techniques. With diffusion as the basis to introduce and remove chemical species into and out of the hydrogel, this method is suitable for smaller bulk geometries and thin films. Characterization of the cellulose nanofiber-palladium composite aerogels with scanning electron microscopy, X-ray diffractometry, thermal gravimetric analysis, nitrogen gas adsorption, electrochemical impedance spectroscopy, and cyclic voltammetry indicates a high surface area, metallized palladium porous structure.


Asunto(s)
Celulosa/síntesis química , Hidrogeles/química , Nanofibras/química , Paladio/química , Adsorción , Celulosa/química , Electroquímica , Nanofibras/ultraestructura , Porosidad , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría , Agua/química , Difracción de Rayos X
4.
Molecules ; 23(7)2018 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-30002301

RESUMEN

Multi-metallic and alloy nanomaterials enable a broad range of catalytic applications with high surface area and tuning reaction specificity through the variation of metal composition. The ability to synthesize these materials as three-dimensional nanostructures enables control of surface area, pore size and mass transfer properties, electronic conductivity, and ultimately device integration. Au-Cu nanomaterials offer tunable optical and catalytic properties at reduced material cost. The synthesis methods for Au-Cu nanostructures, especially three-dimensional materials, has been limited. Here, we present Au-Cu nanofoams and Au-Cu-Pd macrobeams synthesized from salt precursors. Salt precursors formed from the precipitation of square planar ions resulted in short- and long-range ordered crystals that, when reduced in solution, form nanofoams or macrobeams that can be dried or pressed into freestanding monoliths or films. Metal composition was determined with X-ray diffraction and energy dispersive X-ray spectroscopy. Nitrogen gas adsorption indicated an Au-Cu nanofoam specific surface area of 19.4 m²/g. Specific capacitance determined with electrochemical impedance spectroscopy was 46.0 F/g and 52.5 F/g for Au-Cu nanofoams and Au-Cu-Pd macrobeams, respectively. The use of salt precursors is envisioned as a synthesis route to numerous metal and multi-metallic nanostructures for catalytic, energy storage, and sensing applications.


Asunto(s)
Cobre/química , Oro/química , Nanopartículas del Metal/química , Paladio/química , Porosidad
5.
J Vis Exp ; (136)2018 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-29985323

RESUMEN

Here, a method to synthesize gold, palladium, and platinum aerogels via a rapid, direct solution-based reduction is presented. The combination of various precursor noble metal ions with reducing agents in a 1:1 (v/v) ratio results in the formation of metal gels within seconds to minutes compared to much longer synthesis times for other techniques such as sol-gel. Conducting the reduction step in a microcentrifuge tube or small volume conical tube facilitates a proposed nucleation, growth, densification, fusion, equilibration model for gel formation, with final gel geometry smaller than the initial reaction volume. This method takes advantage of the vigorous hydrogen gas evolution as a by-product of the reduction step, and as a consequence of reagent concentrations. The solvent accessible specific surface area is determined with both electrochemical impedance spectroscopy and cyclic voltammetry. After rinsing and freeze drying, the resulting aerogel structure is examined with scanning electron microscopy, X-ray diffractometry, and nitrogen gas adsorption. The synthesis method and characterization techniques result in a close correspondence of aerogel ligament sizes. This synthesis method for noble metal aerogels demonstrates that high specific surface area monoliths may be achieved with a rapid and direct reduction approach.


Asunto(s)
Geles/química , Oro/química , Paladio/química , Platino (Metal)/química , Catálisis
6.
Molecules ; 23(6)2018 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-29890763

RESUMEN

Noble metal aerogels offer a wide range of catalytic applications due to their high surface area and tunable porosity. Control over monolith shape, pore size, and nanofiber diameter is desired in order to optimize electronic conductivity and mechanical integrity for device applications. However, common aerogel synthesis techniques such as solvent mediated aggregation, linker molecules, sol⁻gel, hydrothermal, and carbothermal reduction are limited when using noble metal salts. Here, we present the synthesis of palladium aerogels using carboxymethyl cellulose nanofiber (CNF) biotemplates that provide control over aerogel shape, pore size, and conductivity. Biotemplate hydrogels were formed via covalent cross linking using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) with a diamine linker between carboxymethylated cellulose nanofibers. Biotemplate CNF hydrogels were equilibrated in precursor palladium salt solutions, reduced with sodium borohydride, and rinsed with water followed by ethanol dehydration, and supercritical drying to produce freestanding aerogels. Scanning electron microscopy indicated three-dimensional nanowire structures, and X-ray diffractometry confirmed palladium and palladium hydride phases. Gas adsorption, impedance spectroscopy, and cyclic voltammetry were correlated to determine aerogel surface area. These self-supporting CNF-palladium aerogels demonstrate a simple synthesis scheme to control porosity, electrical conductivity, and mechanical robustness for catalytic, sensing, and energy applications.


Asunto(s)
Carboximetilcelulosa de Sodio/química , Geles/química , Nanofibras/química , Paladio/química , Espectroscopía Dieléctrica , Microscopía Electrónica de Rastreo , Termogravimetría , Difracción de Rayos X
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