Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Br J Educ Psychol ; 93 Suppl 1: 72-89, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35906734

RESUMEN

BACKGROUND: This study investigated the role of different test anxiety components (affective, cognitive, motivational and physiological) as mediators between control and performance as proposed by Pekrun's control-value theory (CVT). While all components were assessed via self-report, the physiological component was additionally assessed via electrodermal activity (EDA). AIMS: We examined the relative impact of the self-reported anxiety components and EDA in this mediating mechanism to identify the most relevant assessment(s) (i.e., self-reported anxiety components and/or EDA) for predicting test performance. SAMPLE: The study comprised 50 eighth graders. METHODS: Data were collected during a mathematics test comprising six task blocks. State self-reports of control and anxiety components along with test performance and other test emotions were collected block-wise (i.e., repeated assessments within students). EDA was continuously recorded. RESULTS: Consistent with CVT, intra-individual mediation analysis with multiple mediators revealed that higher control predicted lower anxiety (i.e., all self-reported components). Unexpectedly, higher control was associated with increased EDA. Follow-up analyses taking other test emotions into account suggested this might reflect positive activation. Correlations between EDA and control and self-reported anxiety components differed depending on which test emotion was dominant in each situation. Regarding test performance, only the cognitive component was a significant mediator and thus seems to play a pivotal role in the relationship between control and performance. CONCLUSIONS: Distinguishing between anxiety components and including unbiased physiological measures improve our understanding of the mechanisms behind the relationship between test anxiety and performance. Higher physiological arousal may be a sign of anxiety but can also be a sign of positive activation. When aiming to reduce negative effects of anxiety on performance, targeting the cognitive component seems crucial. Implications of these findings for educational and psychological practice are discussed.


Asunto(s)
Ansiedad , Emociones , Humanos , Autoinforme , Ansiedad/psicología , Emociones/fisiología , Motivación , Estudiantes/psicología
2.
J Affect Disord ; 310: 235-240, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35533775

RESUMEN

Digital media, including smartphones and social media, are central in youths' lives. This study aimed to examine the role of digital media in psychiatric hospital admissions among adolescents. 343 psychiatrically-hospitalized youth (Mage = 15.2; 70.3% White, 13.7% Black, 33.9% Hispanic; 48.7% female) completed self-report measures of potential digital media-related reasons for hospitalization, patterns of digital media use, and clinical symptoms (internalizing, externalizing, suicidal ideation and attempts). Digital media-related reasons for hospitalization were common, with over 40% of the sample endorsing at least one such reason; 24.8% endorsed having their phone taken away as a reason for admission. Younger adolescents and youth with addictive patterns of phone use were more likely to endorse digital media-related reasons for hospitalization, including phone restriction and negative social media experiences. In addition, youth endorsing suicide-related social media engagement (e.g., posting or messaging about suicide) as a precursor to admission reported more severe suicidal ideation and greater likelihood of a recent suicide attempt. Limitations of the study include a reliance on self-report measures and cross-sectional design. Findings highlight the need to identify youth who may be especially vulnerable to digital media experiences that contribute to risk for psychiatric hospitalization.


Asunto(s)
Internet , Intento de Suicidio , Adolescente , Estudios Transversales , Femenino , Hospitalización , Humanos , Masculino , Ideación Suicida
3.
J Child Adolesc Trauma ; 14(4): 527-531, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34099965

RESUMEN

Since Myers (1915) coined the term 'shell shock' to define the prolonged suffering of soldiers returning from the Great War, the psychological and physical result of distressing experiences, known as trauma, has been of academic interest. Transgenerational transmission of trauma effects has been recorded, demonstrating that on some level, the exposure to trauma of one generation can impact individuals of a subsequent generation (Yehuda & Lehrner, 2018). Observational studies on children of holocaust survivors formed the basis of this trajectory of research (Rakoff, 1966), and eventually this phenomenon became referred to as the transgenerational transmission of trauma (TTT). Since then, TTT has been observed in several contexts, including within families who have experienced high rates historical trauma (O'Neill et al., 2016), within regions high-frequencies of historical war and terrorism (Yehuda & Lehrner, 2018) and those who have undergone famine (Ahmed, 2010). This report aims to outline several pathways (biological, psychological, and sociological) by which trauma may be transmitted across generations. Moreover, it discusses several methods of trauma assessment and the related challenges and benefits. Lastly, this report advocates a biopsychosocial approach - an interdisciplinary model using the interplay of biological, psychological, and social-environmental factors - to research TTT. By promoting the benefits of such an interdisciplinary approach we attempt to break up silos between disciplines and encourage collaboration between academics from various backgrounds researching this topic to better serve individuals impacted by TTT.

4.
J Chromatogr A ; 1532: 161-174, 2018 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-29248345

RESUMEN

The size-exclusion separation of a water-soluble polyelectrolyte polymer, sodium polystyrene sulfonate (NaPSS), was demonstrated on common reversed-phase (C18, C4, phenyl, and cyano) and hydrophilic interaction chromatography (HILIC) columns. The effect of common solvents - acetonitrile (ACN), tetrahydrofuran (THF), and methanol (MeOH), used as mobile phase modifiers - on the elution of NaPSS and the effect of column temperature (within a relatively narrow range corresponding to typical chromatographic conditions, i.e., 10 °C-60 °C) on the partition coefficient, KSEC, were also investigated. Non-size-exclusion chromatography (non-SEC) effects can be minimized by the addition of an electrolyte and an organic modifier to the mobile phase, and by increasing the column temperature (e.g., to 50 °C or 60 °C). Strong solvents such as THF and ACN are more successful in the reduction of such effects than is the weaker solvent MeOH. The best performance is seen on medium polarity and polar stationary phases, such as cyanopropyl- and diol-modified silica (HILIC), where the elution of the NaPSS polyelectrolyte is by a near-ideal SEC mechanism. Hydrophobic stationary phases, such as C18, C4, and phenyl, require a higher concentration of a strong solvent modifier (THF) in the mobile phase to reduce non-SEC interactions of the solute with the stationary phase.


Asunto(s)
Cromatografía en Gel/métodos , Cromatografía de Fase Inversa/métodos , Interacciones Hidrofóbicas e Hidrofílicas , Polielectrolitos/química , Agua/química , Acetonitrilos/química , Calibración , Metanol , Poliestirenos/química , Estándares de Referencia , Sodio/química , Solventes/química , Ácidos Sulfónicos/química , Temperatura , Uracilo/química
5.
J Chromatogr A ; 1531: 83-103, 2018 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-29180220

RESUMEN

Common reversed-phase columns (C18, C4, phenyl, and cyano) offer inert surfaces suitable for the analysis of polymers by size-exclusion chromatography (SEC). The effect of tetrahydrofuran (THF) solvent and the mixtures of THF with a variety of common solvents used in high performance liquid chromatography (acetonitrile, methanol, dimethylformamide, 2-propanol, ethanol, acetone and chloroform) on reversed-phase stationary phase characteristics relevant to size exclusion were studied. The effect of solvent on the elution of polystyrene (PS) and poly(methyl methacrylate) (PMMA) and the effect of column temperature (within a relatively narrow range corresponding to typical chromatographic conditions, i.e., 10°C-60°C) on the SEC partition coefficients KSEC of PS and PMMA polymers, were also investigated. The bonded phases show remarkable differences in size separations when binary mixtures of THF with other solvents are used as the mobile phase. The solvent impact can be two-fold: (i) change of the polymeric coil size, and possible shape, and (ii) change of the stationary phase pore volume. If the effect of this impact is properly moderated, then the greatest benefit of optimized solute resolution can be achieved. Additionally, this work provides an insight on solvent-stationary phase interactions and their effects on column pore volume. The only effect of temperature observed in our studies was a decreased elution volume of the polymers with increasing temperature. SEC partition coefficients were temperature-independent in the range of 10°C-60°C and therefore, over this temperature range elution of PS and PMMA polymers is by near-ideal SEC on reversed-phase columns. Non-ideal SEC appears to occur for high molar mass PMMA polymers on a cyano column when alcohols are used as mobile phase modifiers.


Asunto(s)
Cromatografía en Gel/métodos , Cromatografía de Fase Inversa/métodos , Solventes/química , Furanos/química , Modelos Teóricos , Polimetil Metacrilato/química , Poliestirenos/química , Temperatura
6.
J Chromatogr A ; 1437: 74-87, 2016 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-26877177

RESUMEN

This work describes the applicability of common reversed phase and HILIC columns for size exclusion chromatography of synthetic and natural polymers. Depending on the nature of the solute and column stationary phase, a "non-retention" condition must be created with the aid of the mobile phase to achieve a unique size-based separation in isocratic mode. The various bonded phases show remarkable differences in size separations that are controlled by mobile phase conditions. Polymer-mobile phase and column-mobile phase solvation interactions determine polymer hydrodynamic volume (or solute bulkiness) and polymer-column steric interaction. Solvation interactions in turn depend on polymer, mobile phase and stationary phase polarities. Column-mobile phase solvation interactions determine the structural order of the bonded ligands that can vary from ordered (extended, aligned away from the silica substrate) to disordered (folded, pointing toward the silica substrate). Chain order increases with increased solvent penetration into the bonded phase. Increased chain order reduces pore volume, and therefore decreases the size-separation efficiency of a column. Conversely, decreased chain order increases pore volume and therefore increases the size-separation efficiency. The thermodynamic quality of the mobile phase also plays a significant role in the separation of polymers. "Poor" solvents can significantly reduce the hydrodynamic diameter of a solute and thus change their retention behavior. Medium polarity stationary phases, such as fluoro-phenyl and cyano, exhibit a unique retention behavior. With an appropriate polarity mobile phase, polar and non-polar synthetic polymers of the same molecular masses can be eluted at the same retention volumes.


Asunto(s)
Biopolímeros/análisis , Técnicas de Química Analítica/métodos , Cromatografía en Gel , Polímeros/análisis , Biopolímeros/química , Interacciones Hidrofóbicas e Hidrofílicas , Compuestos Orgánicos/química , Polímeros/química , Dióxido de Silicio/química , Solventes/química
7.
J Pharm Biomed Anal ; 118: 276-283, 2016 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-26580825

RESUMEN

This work describes a simple, sensitive and fast liquid chromatographic method using ultraviolet (UV) detection for the quantitation of Captisol™ (sulfobutyl ether-ß-cyclodextrin, SBE-ß-CD) in Vestipitant (GW597599) IV formulation. The chromatographic system consists of a cyano-modified silica stationary phase column with 0.5mM copper(II) acetate in 50/50 (v/v) water/acetonitrile and 0.05% (v/v) of trifluoroacetic acid as the mobile phase. Due to the fact that SBE-ß-CD does not possess a chromophore suitable for UV detection, copper(II) acetate is used as a detection reagent. At low pH copper(II) acetate interacts with SBE-ß-CD and produces mixed copper(II) [Cu(2+)] chelate and copper(II) mono acetate [CuOAc(+)] complexes, while displacing sodium ions [Na(+)] from the sulfobutyl ether (SBE) group. The copper(II)-SBE-ß-CD interaction has optical properties that allow its detection by UV. This novel method is highly reproducible and reliable for accurate quantitation of SBE-ß-CD content in the Vestipitant IV solution, and in the solution without the Vestipitant matrix.


Asunto(s)
Fluorobencenos/análisis , Fluorobencenos/química , Piperidinas/análisis , Piperidinas/química , beta-Ciclodextrinas/análisis , beta-Ciclodextrinas/química , Administración Intravenosa , Cromatografía Liquida/métodos , Soluciones Farmacéuticas/análisis , Espectrofotometría Ultravioleta/métodos
8.
J Pharm Biomed Anal ; 53(3): 371-5, 2010 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-20478678

RESUMEN

Two unusual chromatographic artifact peaks were detected in the HPLC analysis for content of a malonohydrazide derivative drug and drug-related impurities. The artifacts were identified as the copper(II) chelating complexes with the drug compound and one of the process impurities. Our investigations suggested that built-up of Cu(2+) contamination in the HPLC system was the primary source for formation of the chelating artifacts. A rinse procedure using diluted EDTA solution was developed, and demonstrated to effectively purge trace level of heavy metals including Cu(2+) from the system, and therefore inhibited the formation of both chelates. Furthermore, the rinse was shown to introduce no detrimental impact on the response accuracy of the active drug compound and related impurities.


Asunto(s)
Quelantes/farmacología , Cromatografía Líquida de Alta Presión/métodos , Cobre/aislamiento & purificación , Contaminación de Medicamentos , Ácido Edético/farmacología , Hidrazinas/análisis , Tioamidas/análisis , Artefactos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...