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1.
Disaster Med Public Health Prep ; 17: e22, 2021 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-34247692

RESUMEN

OBJECTIVES: This study sought to identify coronavirus disease 2019 (COVID-19) risk communication materials distributed in Jamaica to mitigate the effects of the disease outbreak. It also sought to explore the effects of health risk communication on vulnerable groups in the context of the pandemic. METHODS: A qualitative study was conducted, including a content analysis of health risk communications and in-depth interviews with 35 purposively selected elderly, physically disabled, persons with mental health disorders, representatives of government agencies, advocacy and service groups, and caregivers of the vulnerable. Axial coding was applied to data from the interviews, and all data were analyzed using the constant comparison technique. RESULTS: Twelve of the 141 COVID-19 risk communication messages directly targeted the vulnerable. All participants were aware of the relevant risk communication and largely complied. Barriers to messaging awareness and compliance included inappropriate message medium for the deaf and blind, rural location, lack of Internet service or digital devices, limited technology skills, and limited connection to agencies that serve the vulnerable. CONCLUSION: The vulnerable are at increased risk in times of crisis. Accessibility of targeted information was inadequate for universal access to health information and support for vulnerable persons regardless of location and vulnerability.

2.
J Pers Soc Psychol ; 119(6): 1459-1477, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31556680

RESUMEN

Theorists have long assumed that people's self-esteem and social relationships influence each other. However, the empirical evidence has been inconsistent, creating substantial uncertainty about whether relationships are in fact an influential factor in self-esteem development and vice versa. This meta-analysis synthesizes the available longitudinal data on the prospective effect of social relationships on self-esteem (48 samples including 46,231 participants) and the prospective effect of self-esteem on social relationships (35 samples including 21,995 participants). All effects controlled for prior levels of the outcomes. Results showed that relationships and self-esteem reciprocally predict each other over time with similar effect sizes (ß = .08 in both directions). Moderator analyses suggested that the effects held across sample characteristics such as mean age, gender, ethnicity, and time lag between assessments, except for the self-esteem effect on relationships, which was moderated by type of relationship partner (stronger for general relationships than for specific partners) and relationship reporter (stronger for self-reported than for informant-reported relationship characteristics). The findings support assumptions of classic and contemporary theories on the influence of social relationships on self-esteem and on the consequences of self-esteem for the relationship domain. In sum, the findings suggest that the link between people's social relationships and their level of self-esteem is truly reciprocal in all developmental stages across the life span, reflecting a positive feedback loop between the constructs. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Asunto(s)
Relaciones Interpersonales , Autoimagen , Humanos , Estudios Longitudinales
3.
J Clin Child Adolesc Psychol ; 48(3): 400-411, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-29048245

RESUMEN

Self-esteem is a potent indicator of mental health in typically developing (TYP) individuals. It is surprising that there have been few comprehensive investigations of self-esteem in children and adolescents with autism spectrum disorder (ASD), given that they are at high risk for comorbid mental health problems, such as depression and anxiety. The objectives of the current study were to assess how youth with ASD rate their self-esteem compared to age-matched TYP youth and to examine how self-esteem relates to internalizing psychopathology and theory of mind in the two groups. Seventy-three children and adolescents, ages 9 to 17, were administered a battery of questionnaires assessing self-esteem and internalizing symptoms, as well as tasks designed to measure theory of mind. Results indicated that youth with ASD rated their self-esteem significantly lower than did TYP youth. Self-esteem was strongly related to depression in both groups but was negatively related to theory of mind only for youth with ASD. These results may provide important insights into how individuals with ASD form evaluations of their own self-worth and illustrate how increasing self-awareness in individuals with ASD is not without risks.


Asunto(s)
Ansiedad/psicología , Depresión/psicología , Autoimagen , Teoría de la Mente/fisiología , Adolescente , Trastorno del Espectro Autista/psicología , Niño , Mecanismos de Defensa , Femenino , Humanos , Masculino , Encuestas y Cuestionarios
4.
J Autism Dev Disord ; 48(5): 1825-1832, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29168089

RESUMEN

A typically developing student's perceptions of his or her own capabilities (academic self-concept), is predictive of later academic achievement. However, little is known about academic self-concept in youth with autism spectrum disorder (ASD). To understand whether students math self-concept and reading self-concept predicted their performance, 44 school-aged children and adolescents with ASD and 36 age-matched individuals with typical development (TYP) rated their perceived math and reading abilities and were administered standardized achievement measures. Results showed self-concept was predictive of performance in math and reading in the TYP group. For youth with ASD, there was agreement between self-concept and performance only in math. These findings suggest that educators should be cautious when interpreting the self-assessments of reading ability in students with ASD.


Asunto(s)
Rendimiento Académico/psicología , Trastorno del Espectro Autista/psicología , Matemática , Lectura , Autoimagen , Estudiantes/psicología , Rendimiento Académico/tendencias , Éxito Académico , Adolescente , Aptitud/fisiología , Trastorno del Espectro Autista/diagnóstico , Niño , Comprensión/fisiología , Femenino , Humanos , Masculino , Matemática/normas , Instituciones Académicas/tendencias
5.
J Pers Assess ; 100(1): 84-95, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28631973

RESUMEN

This article introduces the Lifespan Self-Esteem Scale (LSE), a short measure of global self-esteem suitable for populations drawn from across the lifespan. Many existing measures of global self-esteem cannot be used across multiple developmental periods due to changes in item content, response formats, and other scale characteristics. This creates a need for a new lifespan scale so that changes in global self-esteem over time can be studied without confounding maturational changes with alterations in the measure. The LSE is a 4-item measure with a 5-point response format using items inspired by established self-esteem scales. The scale is essentially unidimensional and internally consistent, and it converges with existing self-esteem measures across ages 5 to 93 (N = 2,714). Thus, the LSE appears to be a useful measure of global self-esteem suitable for use across the lifespan as well as contexts where a short measure is desirable, such as populations with short attention spans or large projects assessing multiple constructs. Moreover, the LSE is one of the first global self-esteem scales to be validated for children younger than age 8, which provides the opportunity to broaden the field to include research on early formation and development of global self-esteem, an area that has previously been limited.


Asunto(s)
Inventario de Personalidad/normas , Autoimagen , Encuestas y Cuestionarios/normas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicometría , Reproducibilidad de los Resultados , Adulto Joven
6.
Arch Med Sci Atheroscler Dis ; 2: e61-e67, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29242846

RESUMEN

INTRODUCTION: The aim of the study was to determine the prevalence of dyslipidemia among primary care patients with hypertension and diabetes in Jamaica and the proportion of patients who achieve recommended targets. MATERIAL AND METHODS: An audit of 500 dockets of adult patients with chronic disease attending public primary care clinics in Jamaica was conducted between October and December 2013. Data were collected on patient characteristics including medical history, medications, anthropometry, and lipid profiles (since January 1, 2011). Lipid targets were based on the Ministry of Health 2007 management guidelines. Stepwise multivariable logistic regression analysis was performed to determine the predictors of achieving lipid targets. RESULTS: Four hundred and thirty-seven patient records had a lipid profile done and 90% of these had at least one abnormal lipid value. 15.3% of the patients achieved the low density lipoprotein cholesterol (LDL-C) target, 63.2% high density lipoprotein cholesterol (HDL-C), 85.1% triglycerides and 57.4% the total cholesterol target. Statins were prescribed for 49% and these patients were less likely to achieve LDL-C (OR = 0.57; 95% CI: 0.33-0.97; p = 0.04) or total cholesterol (OR = 0.21; 95% CI: 0.13-0.33; p < 0.001) targets. Patients over 80 years were more likely to achieve the LDL-C target (OR = 3.21; 95% CI: 1.64-6.28; p = 0.002) than those less than 50 years old. More men than women achieved total cholesterol targets (OR = 2.2; 95% CI: 1.4-3.6; p = 0.001). CONCLUSIONS: Dyslipidemia is widespread among primary care patients with hypertension and diabetes. The proportion of patients who achieve the respective lipid targets must be documented and routinely monitored and appropriate medication and lifestyle changes implemented to improve this.

7.
Child Dev ; 88(6): 1810-1822, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28892127

RESUMEN

The current study explored parental processes associated with children's global self-esteem development. Eighty 5- to 13-year-olds and one of their parents provided qualitative and quantitative data through questionnaires, open-ended questions, and a laboratory-based reminiscing task. Parents who included more explanations of emotions when writing about the lowest points in their lives were more likely to discuss explanations of emotions experienced in negative past events with their child, which was associated with child attachment security. Attachment was associated with concurrent self-esteem, which predicted relative increases in self-esteem 16 months later, on average. Finally, parent support also predicted residual increases in self-esteem. Findings extend prior research by including younger ages and uncovering a process by which two theoretically relevant parenting behaviors impact self-esteem development.


Asunto(s)
Apego a Objetos , Relaciones Padres-Hijo , Responsabilidad Parental/psicología , Autoimagen , Apoyo Social , Adolescente , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Masculino
8.
J Phys Chem B ; 121(29): 7042-7047, 2017 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-28628320

RESUMEN

Steady state spectroscopy, femtosecond transient absorption spectroscopy (fsTA), and femtosecond stimulated Raman spectroscopy (FSRS) of DNA mini-hairpins possessing a diphenylacetylenedicarboxamide (DPA) linker and 1-3 adenine-thymine (A-T) or guanine-cytosine (G-C) base pairs have been investigated. Ultraviolet and circular dichroism (UV and CD) spectra are consistent with ground state conformations that are predominantly base-paired and π-stacked for conjugates possessing two or three base pairs; however, they offer no information concerning the conformation of conjugates possessing a single base pair. fsTA spectra are indicative of π-stacked structures excepted in the case of the conjugate possessing a single G-C base pair. All of the conjugates display transient absorption bands characteristic of the DPA-. anion radical. Conjugates possessing two or three G-C base pairs display a transient absorption band characteristic of the short-lived G+• cation radical. The mini-hairpins with 1-3 A-T base pairs do not display the transient absorption band characteristic of the (An+•) polaron. This implies that an A-tract with three base pairs is too short to support polaron formation.


Asunto(s)
ADN/química , Emparejamiento Base , Dipéptidos , Fenilalanina/análogos & derivados , Fenilalanina/química , Recombinación Genética
9.
ACS Appl Mater Interfaces ; 9(39): 33493-33503, 2017 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-28430417

RESUMEN

Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated π-stacked columns. Following photoexcitation of the ordered ribbons, ZnP+•-PDI-• radical ion pairs form in <200 fs and subsequently produce a 30 ± 3% yield of free charge carriers that live for about 100 µs. Elongating the side chains on ZnP and PDI in 1b enhances the order of the films, but does not result in an increase in free charge carrier yield. In addition, this yield is independent of temperature, free energy of reaction, and the ZnP-PDI distance in the covalent dyad. These results suggest that the free charge carrier yield in this system is not limited by a bound charge transfer (CT) state or promoted by a vibronically hot CT state. Instead, it is likely that π-stacking of the segregated donors and acceptors within the ribbons results in delocalization of the charges following photoexcitation, allowing them to overcome Coulombic attraction and generate free charge carriers.

10.
J Am Chem Soc ; 139(5): 1730-1733, 2017 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-28094928

RESUMEN

The dynamics and efficiency of photoinduced charge transport has been investigated in DNA capped hairpins possessing a stilbenedicarboxamide (Sa) hole donor and stilbenediether (Sd) hole acceptor separated by DNA G-quadruplex structures possessing 2-to-4 tetrads by means of femtosecond and nanosecond transient absorption spectroscopy with global analysis. The results for the quadruplex structures are compared with those for the corresponding duplex structures having G-C base pairs in place of the G-tetrads. Following photoinduced charge separation to form a contact radical ion pair, hole transport to form the Sa-•/Sd+• charge-separated state is slower but more efficient for the quadruplex vs duplex structures. Thus, the G-quadruplex serves as an effective conduit for positive charge rather than as a hole trap when inserted into a duplex, as previously postulated.


Asunto(s)
ADN/química , G-Cuádruplex , Éteres/química , Estructura Molecular , Procesos Fotoquímicos , Estilbenos/química , Termodinámica
11.
J Am Chem Soc ; 139(2): 749-756, 2017 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-28026177

RESUMEN

Photodriven electron transfer from a donor excited state to an assembly of electronically coupled acceptors has been proposed to enhance charge transfer efficiency in functional organic electronic materials. However, the circumstances under which this may occur are difficult to investigate in a controlled manner in disordered donor-acceptor materials. Here we investigate the effects of anion delocalization on electron transfer using zinc meso-tetraphenylporphyrin (ZnTPP) as a donor and a perylene-3,4:9,10-bis(dicarboximide) dimer as the acceptor (PDI2). The PDI units of the dimer are positioned in a cofacial orientation relative to one another by attachment of the imide group of each PDI to the 4- and 5-positions of a xanthene spacer. Furthermore, the distal imide group of one PDI is linked to the para-position of one ZnTPP phenyl group to yield ZnTPP-PDI2. The data for the dimer are compared to two different ZnTPP-PDI monomer reference systems designed to probe electron transfer to each of the individual PDI molecules comprising PDI2. The electron transfer rate from the ZnTPP lowest excited singlet state to PDI2 is increased by 50% relative to that in ZnTPP-PDI, when the data are corrected for the statistics of having two electron acceptors. Femtosecond transient IR absorption spectroscopy provides evidence that the observed enhancement in charge separation results from electron transfer producing a delocalized PDI2 anion.

12.
Nat Chem ; 8(11): 1015-1021, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27768107

RESUMEN

Charge transport through the DNA double helix is of fundamental interest in chemistry and biochemistry, but also has potential technological applications such as for DNA-based nanoelectronics. For the latter, it is of considerable interest to explore ways to influence or enhance charge transfer. In this Article we demonstrate a new mechanism for DNA charge transport, namely 'deep-hole transfer', which involves long-range migration of a hole through low-lying electronic states of the nucleobases. Here, we demonstrate, in a combined experimental and theoretical study, that it is possible to achieve such transfer behaviour by changing the energetics of charge injection. This mechanism leads to an enhancement in transfer rates by up to two orders of magnitude and much weaker distance dependence. This transfer is faster than relaxation to the lowest-energy state, setting this mechanism apart from those previously described. This opens up a new direction to optimize charge transfer in DNA with unprecedented charge-transfer rates.


Asunto(s)
ADN/química , Dicroismo Circular , ADN/metabolismo , Electrónica , Modelos Moleculares , Nanotecnología , Conformación de Ácido Nucleico , Teoría Cuántica , Estilbenos/química
13.
Dev Psychol ; 52(10): 1563-1577, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27690495

RESUMEN

A large body of literature suggests a clear, concurrent association between peer approval and self-esteem in adolescence. However, little empirical work exists on either the prospective or reciprocal relation between peer approval and self-esteem during this age period. Moreover, it is unclear from past research whether both subjectively perceived peer approval and objectively measured peer approval are related to subsequent self-esteem over time (and vice versa) and whether these paths have long-term associations into adulthood. Using data from a large longitudinal study that covers a time span of 2 decades, we examined reciprocal, prospective relations between self-esteem and peer approval during ages 12-16 in addition to long-term relations between these variables and later social constructs at age 35. Cross-lagged regression analyses revealed small but persistent effect sizes from both types of peer approval to subsequent self-esteem in adolescence, controlling for prior self-esteem. However, effects in the reverse direction were not confirmed. These findings support the notion that peer relationships serve an important function for later self-esteem, consistent with many theoretical tenets of the importance of peers for building a strong identity. Finally, we found long-term relations between adult social constructs and adolescent objective and subjective peer approval as well as self-esteem. Therefore, not only do peer relationships play a role in self-esteem development across adolescence, but they remain impactful throughout adulthood. In sum, the current findings highlight the lasting, yet small link between peer relationships and self-esteem development and call for investigations of further influential factors for self-esteem over time. (PsycINFO Database Record


Asunto(s)
Desarrollo del Adolescente , Relaciones Interpersonales , Grupo Paritario , Autoimagen , Adolescente , Adulto , Factores de Edad , Niño , Femenino , Humanos , Estudios Longitudinales , Masculino , Modelos Psicológicos , Apoyo Social
14.
J Am Chem Soc ; 138(17): 5491-4, 2016 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-27082662

RESUMEN

The excited state behavior of DNA hairpins possessing a diphenylacetylenedicarboxamide (DPA) linker separated from a single guanine-cytosine (G-C) base pair by zero-to-six adenine-thymine (A-T) base pairs has been investigated. In the case of hairpins with zero or one A-T separating DPA and G, formation of both DPA anion radical (DPA(-•)) and G cation radical (G(+•)) are directly observed and characterized by their transient absorption and stimulated Raman spectra. For hairpins with two or more intervening A-T, the transient absorption spectra of DPA(-•) and the adenine polaron (An(+•)) are observed. In addition to characterization of the hole carriers, the dynamics of each step in the charge separation and charge recombination process as well as the overall efficiency of charge separation have been determined, thus providing a complete account of the mechanism and dynamics of photoinduced charge transport in these DNA hairpins.


Asunto(s)
ADN/química , Procesos Fotoquímicos , Conformación de Ácido Nucleico , Análisis Espectral/métodos
15.
Biochem Mol Biol Educ ; 44(4): 326-35, 2016 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-26923186

RESUMEN

Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure-function relationships at the molecular level, which they cannot as effectively visualize. Students need to develop accurate, 3-dimensional mental models of biomolecules to understand how biomolecular structure affects cellular functions at the molecular level, yet most traditional curricular tools such as textbooks include only 2-dimensional representations. We used a controlled, backward design approach to investigate how hand-held physical molecular model use affected students' ability to logically predict structure-function relationships. Brief (one class period) physical model use increased quiz score for females, whereas there was no significant increase in score for males using physical models. Females also self-reported higher learning gains in their understanding of context-specific protein function. Gender differences in spatial visualization may explain the gender-specific benefits of physical model use observed. © 2016 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 44(4):326-335, 2016.


Asunto(s)
Bioquímica/educación , Comprensión , Aprendizaje , Proteínas Asociadas a Microtúbulos/química , Antígenos de Histocompatibilidad Menor/química , Modelos Anatómicos , Reconocimiento en Psicología , Estudiantes/psicología , Gráficos por Computador , Femenino , Humanos , Imagenología Tridimensional , Masculino , Estructura Secundaria de Proteína , Relación Estructura-Actividad
16.
J Phys Chem B ; 120(4): 756-65, 2016 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-26731377

RESUMEN

Connecting electron donors and acceptors to a benzene ring in a meta or para relationship results in quantum interference effects that can strongly influence charge separation (CS) and charge recombination (CR) processes in these systems. We report on the energy and electron transfer behavior of chlorophyll-based para- and meta-linked donor-bridge-acceptor (D-B-A) dyads, where the semisynthetic chlorophyll a derivative, zinc methyl 3-ethyl-pyrochlorophyllide a (D), is covalently attached at its 20-position to the para position of one phenyl of diphenylacetylene (B). The meta or para position of the phenyl in B distal to the donor is in turn attached to perylene-3,4:9,10-bis(dicarboximide) (PDI) (A). Photoexcitation of the D-B-A dyads produces long-lived radical ion pairs D(•+)-B-A(•-), which recombine to the ground state and to both (3*)D-B-A and D-B-(3*)A. Time-resolved optical and electron paramagnetic resonance spectroscopies were used to monitor the charge transfer and triplet energy transfer (TEnT) processes. At longer times, TEnT occurs from (3*)D-B-A to D-B-(3*)A. Surprisingly, the D-B-A molecules linked via the meta linkage exhibit faster CS, CR, and TEnT rates than do those with the para linkage in contrast to most other meta/para-linked D-B-A molecules previously examined.


Asunto(s)
Clorofila/química , Perileno/química , Procesos Fotoquímicos
17.
Faraday Discuss ; 185: 105-20, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26442603

RESUMEN

The effects of an artificial cyclohexyl base pair on the quantum yields of fluorescence and dynamics of charge separation and charge recombination have been investigated for several synthetic DNA hairpins. The hairpins possess stilbenedicarboxamide, perylenediimide, or naphthalenediimide linkers and base-paired stems. In the absence of the artificial base pair hole injection into both adenine and guanine purine bases is exergonic and irreversible, except in the case of stilbene with adenine for which it is slightly endergonic and reversible. Insertion of the artificial base pair renders hole injection endergonic or isoergonic except in the case of the powerful naphthalene acceptor for which it remains exergonic. Both hole injection and charge recombination are slower for the naphthalene acceptor in the presence of the artificial base pair than in its absence. The effect of an artificial base pair on charge separation and charge recombination in hairpins possessing stilbene and naphthalene acceptor linkers and a stilbenediether donor capping group has also been investigated. In the case of the stilbene acceptor-stilbene donor capped hairpins photoinduced charge separation across six base pairs is efficient in the absence of the artificial base pair but does not occur in its presence. In the case of the naphthalene acceptor-stilbene donor capped hairpins the artificial base pair slows but does not stop charge separation and charge recombination, leading to the formation of long-lived charge separated states.


Asunto(s)
Ciclohexanos/química , ADN/química , Fotoquímica , Emparejamiento Base , Imidas/química , Perileno/análogos & derivados , Perileno/química
18.
J Phys Chem B ; 119(32): 10231-43, 2015 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-26230425

RESUMEN

Lipid vesicles are used as the organizational structure of self-assembled light-harvesting systems. Following analysis of 17 chromophores, six were selected for inclusion in vesicle-based antennas. The complementary absorption features of the chromophores span the near-ultraviolet, visible, and near-infrared region. Although the overall concentration of the pigments is low (~1 µM for quantitative spectroscopic studies) in a cuvette, the lipid-vesicle system affords high concentration (≥10 mM) in the bilayer for efficient energy flow from donor to acceptor. Energy transfer was characterized in 13 representative binary mixtures using static techniques (fluorescence-excitation versus absorptance spectra, quenching of donor fluorescence, modeling emission spectra of a mixture versus components) and time-resolved spectroscopy (fluorescence, ultrafast absorption). Binary donor-acceptor systems that employ a boron-dipyrrin donor (S0 ↔ S1 absorption/emission in the blue-green) and a chlorin or bacteriochlorin acceptor (S0 ↔ S1 absorption/emission in the red or near-infrared) have an average excitation-energy-transfer efficiency (ΦEET) of ~50%. Binary systems with a chlorin donor and a chlorin or bacteriochlorin acceptor have ΦEET ∼ 85%. The differences in ΦEET generally track the donor-fluorescence/acceptor-absorption spectral overlap within a dipole-dipole coupling (Förster) mechanism. Substantial deviation from single-exponential decay of the excited donor (due to the dispersion of donor-acceptor distances) is expected and observed. The time profiles and resulting ΦEET are modeled on the basis of (Förster) energy transfer between chromophores relatively densely packed in a two-dimensional compartment. Initial studies of two ternary and one quaternary combination of chromophores show the enhanced spectral coverage and energy-transfer efficacy expected on the basis of the binary systems. Collectively, this approach may provide one of the simplest designs for self-assembled light-harvesting systems that afford broad solar collection and efficient energy transfer.


Asunto(s)
Complejos de Proteína Captadores de Luz/química , Liposomas Unilamelares/química , Boro/química , Simulación por Computador , Transferencia Resonante de Energía de Fluorescencia , Cinética , Membrana Dobles de Lípidos/química , Modelos Químicos , Fosfatidilcolinas/química , Procesos Fotoquímicos , Porfirinas/química , Análisis Espectral
19.
Child Dev ; 86(4): 995-1013, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25703089

RESUMEN

Close parent-child relationships are viewed as important for the development of global self-esteem. Cross-sectional research supports this hypothesis, but longitudinal studies provide inconsistent prospective effects. The current study uses data from Germany (N = 982) and the United States (N = 451) to test longitudinal relations between parent-child closeness and adolescent self-esteem. The authors used self-, parent-, and observer-reported parent-child closeness and self-reported self-esteem from ages 12 to 16. Results replicated concurrent correlations found in the literature, but six longitudinal models failed to show prospective relations. Thus, the longitudinal effect of parent-child closeness and self-esteem is difficult to detect with adolescent samples. These findings suggest the need for additional theorizing about influences on adolescent self-esteem development and longitudinal research with younger samples.

20.
Photochem Photobiol ; 91(2): 331-42, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25488432

RESUMEN

Photosynthetic organisms are adapted to light characteristics in their habitat in part via the spectral characteristics of the associated chlorophyll pigments, which differ in the position of a formyl group around the chlorin macrocycle (chlorophylls b, d, f) or no formyl group (chlorophyll a). To probe the origin of this spectral tuning, the photophysical and electronic structural properties of a new set of synthetic chlorins are reported. The zinc and free base chlorins have a formyl group at either the 2- or 3-position. The four compounds have fluorescence yields in the range 0.19-0.28 and singlet excited-state lifetimes of ca 4 ns for zinc chelates and ca 8 ns for the free base forms. The photophysical properties of the 2- and 3-formyl zinc chlorins are similar to those observed previously for 13-formyl or 3,13-diformyl chlorins, but differ markedly from those for 7-formyl analogs. Molecular-orbital characteristics obtained from density functional theory (DFT) calculations were used as input to spectral simulations employing the four-orbital model. The analysis has uncovered the key changes in electronic structure engendered by the presence/location of a formyl group at various macrocycle positions, which is relevant to understanding the distinct spectral properties of the natural chlorophylls a, b, d and f.


Asunto(s)
Materiales Biomiméticos/química , Complejos de Coordinación/química , Electrones , Porfirinas/química , Zinc/química , Materiales Biomiméticos/síntesis química , Clorofila/análogos & derivados , Clorofila/química , Clorofila A , Complejos de Coordinación/síntesis química , Fluorescencia , Luz , Magnesio/química , Porfirinas/síntesis química , Teoría Cuántica , Espectrometría de Fluorescencia
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