Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Soc Work ; 69(3): 241-253, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38697192

RESUMO

This study was designed to investigate the relationship between authentic behavior and job satisfaction among child welfare caseworkers in Pennsylvania. Confirmatory factor analysis was conducted to validate the domains of the Authentic Behavior Scale (balanced processing, relational transparency, and internalized morality) and Job Satisfaction Scale, and the results provided consistent support for the factorial structure of the scales across child welfare caseworkers. The findings of this study revealed a positive correlation between authentic behavior and job satisfaction. To further explore this relationship, a path model was developed that included the elements of authentic behavior, job satisfaction, and demographic variables. The results indicated an association between the type of agency and internalized morality, impacting job satisfaction. Private workers showed a higher level of authentic behavior compared with public workers, with authentic behavior associated with greater job satisfaction. The findings suggest that authentic behavior can play a crucial role in social work practice and warrants considerable attention.


Assuntos
Proteção da Criança , Satisfação no Emprego , Humanos , Masculino , Feminino , Proteção da Criança/psicologia , Pennsylvania , Adulto , Inquéritos e Questionários , Criança , Pessoa de Meia-Idade , Serviço Social/métodos , Análise Fatorial
2.
Ground Water ; 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37847079

RESUMO

Coastal aquifers are complex systems governed by fresh-saline water interactions and ocean tidal effects. The vertical electrical conductivity (EC) and temperature (T) are general indicators for detecting the fresh-saline water interface (FSI) and sea water intrusion in groundwater wells located in coastal aquifers. In this method brief, we developed a cost-effective Arduino-based automatic-vertical profile monitoring system (A-VPMS) to continuously record vertical EC and T in groundwater wells, with the aim of testing its effectiveness in spatiotemporal monitoring of the FSI in a coastal aquifer located in eastern Korea. By analyzing the high-density EC and T data obtained by the A-VPMS, we evaluated the characteristics of the FSI, such as depth and spatial distribution. Our established EC and T data collection method using the A-VPMS proved to be efficient and reliable, providing an excellent tool for fine-scale temporal and spatial understanding of sea water intrusion. The results of this study demonstrate the potential of the A-VPMS for continuous monitoring of the FSI in coastal aquifers, which is crucial for sustainable management of groundwater resources.

3.
Am J Phys Med Rehabil ; 102(8): 715-719, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37104642

RESUMO

ABSTRACT: Inpatient falls have a significant impact on the outcomes of older patients during inpatient rehabilitation. A retrospective case-control study was conducted using data of 7066 adults aged 55 yrs or older to evaluate significant predictors of inpatient falls during inpatient rehabilitation and the association of inpatient falls with discharge destination and length of stay. A stepwise logistic regression was used to model odds of inpatient falls and home discharge with demographic and clinical characteristic variables and a multivariate linear regression to evaluate the association between inpatient falls and length of stay.Nine hundred thirty-one of 7066 patients (13.18%) had inpatient falls during inpatient rehabilitation. The group with inpatient falls had longer length of stay (14.22 ± 7.82 vs. 11.85 ± 5.33 days, P < 0.0001) and a decreased proportion of home discharges when compared with the group without inpatient falls. There were increased odds of inpatient falls among patients with diagnoses of head injury, other injuries, a history of falls, dementia, a divorced marital status, and a use of laxatives or anticonvulsants. Inpatient falls were associated with an increased length of stay (coefficient = 1.62, confidence interval = 1.19-2.06) and decreased odds of home discharge (odds ratio = 0.79, confidence interval = 0.65-0.96) after inpatient rehabilitation. This knowledge may be incorporated into strategies for reducing inpatient falls during inpatient rehabilitation.


Assuntos
Pacientes Internados , Alta do Paciente , Adulto , Humanos , Estudos de Casos e Controles , Estudos Retrospectivos , Tempo de Internação
4.
Am J Phys Med Rehabil ; 102(4): 353-359, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36095159

RESUMO

OBJECTIVE: The aim of the study is to evaluate opioid analgesic utilization and predictors for adverse events during hospitalization and discharge disposition among patients admitted with osteoarthritis or spine disorders. DESIGN: This is a retrospective study of 12,747 adult patients admitted to six private community hospitals from 2017 to 2020. Opioid use during hospitalization and risk factors for hospital-acquired adverse events and nonhome discharge were investigated. RESULTS: The total number of patients using opioids decreased; however, the daily morphine milligram equivalent use for patients on opioids increased from 2017 to 2020. Increased odds of nonhome discharge were associated with older age, Medicaid, Medicare insurance, and increased lengths of stay, increased body mass index, daily morphine milligram equivalent, and electrolyte replacement in the osteoarthritis group. In the spine group, older age, Black race, Medicaid, Medicare, no insurance, increased Charlson Comorbidity Index, lengths of stay, polypharmacy, and heparin use were associated with nonhome discharge. Adverse events were associated with increased age, lengths of stay, Medicare, polypharmacy, antiemetic, and benzodiazepine use in the osteoarthritis group and increased Charlson Comorbidity Index, lengths of stay, and electrolyte replacement in the spine group. CONCLUSIONS: Despite the decreasing number of patients using opioids over the years, patients on opioids had an increased daily morphine milligram equivalent over the same period.


Assuntos
Analgésicos Opioides , Osteoartrite , Adulto , Humanos , Idoso , Estados Unidos , Analgésicos Opioides/uso terapêutico , Estudos Retrospectivos , Pacientes Internados , Medicare , Hospitalização , Hospitais , Osteoartrite/tratamento farmacológico , Eletrólitos , Derivados da Morfina
5.
Int J Alzheimers Dis ; 2022: 5406196, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35127157

RESUMO

A multigenerational household is no longer a rare phenomenon in contemporary society. However, relevant literature has focused on elderly parents receiving support from their adult child, thereby coresiding. This is potentially problematic, as both generations could benefit from living together, and little is known about the benefit of living with adult children from older adults' perspectives compared to the risk of this living situation. Previous research suggests a significant negative effect of living alone, e.g., low psychological well-being, and it becomes more salient among single parents, such as widowed or divorced. The current paper utilizes the National Health Measurement Study with a sample of age 55 and over. Their SF-36 Mental Health and Physical Health Component and self-acceptance scores were measured. Path analysis reveals that both physical and mental health and self-acceptance scores are lower among single older adults at the time of the survey (e.g., divorced and widowed) than among those who are nonsingle and living with their adult child. A complete mediation effect of living with an adult child on older adults' mental health and self-acceptance was observed in both White and non-White minority older adults. This suggests that living with an adult child possibly serves as a protective factor for the negative relationship between living alone and their well-being. The current study seeks to stimulate ideas that might generate the following answer to community-based care in our contemporary aging society.

6.
ACS Appl Mater Interfaces ; 13(21): 24624-24633, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34003000

RESUMO

A simple wet-chemical route for the preparation of core-shell-structured catalysts was developed to achieve high oxygen reduction reaction (ORR) activity with a low Pt loading amount. Nickel nitride (Ni3N) nanoparticles were used as earth-abundant metal-based cores to support thin Pt layers. To realize the site-selective formation of Pt layers on the Ni3N core, hydrogen molecules (H2) were used as a mild reducing agent. As H2 oxidation is catalyzed by the surface of Ni3N, the redox reaction between H2 and Pt(IV) in solution was facilitated on the Ni3N surface, which resulted in the selective deposition of Pt on Ni3N. The controlled Pt formation led to a subnanometer (0.5-1 nm)-thick Pt shell on the Ni3N core. By adopting the core-shell structure, higher ORR activity than the commercial Pt/C was achieved. Electrochemical measurements showed that the thin Pt layer on Ni3N nanoparticle exhibits 5 times higher mass activity and specific activity than that of commercial Pt/C. Furthermore, it is expected that the proposed simple wet-chemical method can be utilized to prepare various transition-metal-based core-shell nanocatalysts for a wide range of energy conversion reactions.

7.
Polymers (Basel) ; 12(5)2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32353941

RESUMO

The possibility of exchange reactions and thermal self-healing in blends of thermoplastic polyurethane (TPU) and phenoxy resin was investigated herein. The analyses were based on characterization obtained via differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and tensile test. A new phenoxy resin was synthesized from eugenol, and blends with different types of TPU were prepared to investigate the exchange reaction, thermal self-healing, and mechanical properties. The influence of phenoxy resin content on the mechanical behavior and healing efficiency was studied. Improvement of storage modulus owing to the increase of phenoxy resin content was observed. Results suggest that the exchange reaction between phenoxy- and ester-type TPU occurred during thermal treatment. However, little exchange occurred between phenoxy resin and ether-type TPU. Specifically, only ester-type TPU exhibited a significant exchange reaction in the phenoxy resin blend. Furthermore, in the presence of a catalyst (e.g., zinc acetate), the exchange reaction readily occurred, and the healing efficiency improved by the addition of the catalyst and increase in the phenoxy content.

8.
Sci Rep ; 10(1): 7866, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398830

RESUMO

An effective method, involving time and frequency domains was developed to interpret seismic precursors by comparing groundwater-level fluctuations recorded immediately and long before the occurrence of a known earthquake. The proposed method, consisting of the pre-processing (3-point filtering, band-pass filtering, and spectrum analysis) and post-processing (weighted moving average method and histogram and spectrum analyses) stages, was applied to the groundwater-level time series measured at three monitoring wells on Jeju Island, South Korea, from 00:00 on 8 September 2016 to 00:00 on 22 September 2016. The Gyeongju earthquake (Mw 5.4) occurred at 20:32 on 12 September2016. The histogram analysis exhibited an accentuating bellshape as the total number of waveforms, including those caused by the earthquake, of the groundwater-level fluctuations increased. The weighted moving average analysis indicated that various abnormal waveforms with different periods occurred in the fluctuations approaching the occurrence of the earthquake. The periods of seismic precursors in the groundwater-level fluctuations were determined by spectrum analysis and varied among the monitoring wells. Seismic precursor responses attributable to the Gyeongju earthquake were identified at least 8 hours before the earthquake, and the method used in this study indicates its good potential to predict an impending earthquake.

9.
ACS Appl Mater Interfaces ; 12(14): 16286-16297, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32167736

RESUMO

Galvanic displacement reaction has been considered a simple method for fabricating hollow nanoparticles. However, the formation of hollow interiors in nanoparticles is not easily achieved owing to the easy oxidization of transition metals, which results in mixed morphologies, and the presence of surfactants on the nanoparticle surface, which severely deteriorates the catalytic activity. In this study, we developed a facile gram-scale methodology for the one-pot preparation of carbon-supported PtNi hollow nanoparticles as an efficient and durable oxygen reduction electrocatalyst without using stabilizing agents or additional processes. The hollow structures were evolved from sacrificial Ni nanoparticles via an in situ galvanic displacement reaction with a Pt precursor, directly following a preannealing process. By sampling the PtNi/C hollow nanoparticles at various reaction times, the structural formation mechanism was investigated using transmission electron microscopy with energy-dispersive X-ray spectroscopy mapping/line-scan profiling. We found out that the structure and morphology of the PtNi hollow nanoparticles were controlled by the acidity of the metal precursor solution and the nanoparticle core size. The synthesized PtNi hollow nanoparticles acted as an oxygen reduction electrocatalyst, with a catalytic activity superior to that of a commercial Pt catalyst. Even after 10 000 cycles of harsh accelerated durability testing, the PtNi/C hollow electrocatalyst showed high performance and durability. We concluded that the Pt-rich layers on the PtNi hollow nanoparticles improved the catalytic activity and durability considerably.

10.
Ground Water ; 58(6): 951-961, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32112397

RESUMO

This paper describes the impacts of the M5.8(5.1) Gyeongju earthquakes on groundwater levels using data obtained from a unique coastal monitoring well. The monitoring strategy integrates conventional water level monitoring with periodic, continuous measurements of temperature and electrical conductivity (EC) within the water column of the well. Another important component of the monitoring system is a new instrument, the InterfacEGG, which is capable of dynamically tracking the freshwater-saltwater interface. Although the system was set up to monitor seawater intrusion related to over-pumping, as well as rainfall and tidal effects, it recorded impacts associated with a large earthquake and aftershocks approximately 241 km away. Seismic energies associated with the M5.8(5.1) Gyeongju earthquakes induced groundwater flows to the monitoring well through fractures and joints in the crystalline basement rocks. Temperature and EC logging data showed that the EC vertical profile declined from an average of approximately 5300 to 4800 µS/cm following the earthquakes. The temperature profile showed a trend toward lower temperatures as the depth increased, a feature not commonly observed in previous studies. Data from the InterfacEGG suggested that the rise in EC was not due to the saltwater intrusion, but from the tendency for brackish water entering the borehole to induce convective mixing at deeper depths as the seismic waves travel through the well-aquifer system. The increase in groundwater levels was caused by pulse of colder, less brackish water flowing into the well because of the earthquake. This behavior reflects an enhancement in rock permeability by removing precipitates and colloidal particles from clogged fractures, which improve the hydraulic connection with a nearby unit with a higher hydraulic head. This study suggests there is value added with a more aggressive monitoring strategy.


Assuntos
Terremotos , Água Subterrânea , Monitoramento Ambiental , República da Coreia , Água do Mar
11.
ACS Omega ; 4(21): 19225-19237, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31763546

RESUMO

Tin oxide (SnO2) has been widely accepted as an effective electron transport layer (ETL) for optoelectronic devices because of its outstanding electro-optical properties such as its suitable band energy levels, high electron mobility, and high transparency. Here, we report a simple but effective interfacial engineering strategy to achieve highly efficient and stable inverted organic solar cells (iOSCs) via a low-temperature solution process and an SnO2 ETL modified by zwitterion nondetergent sulfobetaine 3-(4-tert-butyl-1-pyridinio)-1-propanesulfonate (NDSB-256-4T). We found that NDSB-256-4T helps reduce the work function of SnO2, resulting in more efficient electron extraction and transport to the cathode of iOSCs. NDSB-256-4T also passivates the defects in SnO2, which serves as recombination centers that greatly reduce the device performance of iOSCs. In addition, NDSB-256-4T provides the better interfacial contact between SnO2 and the active layer. Thus, a higher power conversion efficiency (PCE) and longer device stability of iOSCs are expected for a combination of SnO2 and NDSB-256-4T than for devices based on SnO2 only. With these enhanced interfacial properties, P3HT:PC60BM-based iOSCs using SnO2/NDSB-256-4T (0.2 mg/mL) as an ETL showed both a higher average PCE of 3.72%, which is 33% higher than devices using SnO2 only (2.79%) and excellent device stability (over 90% of the initial PCE remained after storing 5 weeks in ambient air without encapsulation). In an extended application of the PTB7-Th:PC70BM systems, we achieved an impressive average PCE of 8.22% with SnO2/NDSB-256-4T (0.2 mg/mL) as the ETL, while devices based on SnO2 exhibited an average PCE of only 4.45%. Thus, the use of zwitterion to modify SnO2 ETL is a promising way to obtain both highly efficient and stable iOSCs.

12.
Polymers (Basel) ; 11(10)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615025

RESUMO

With limited biomass that can be currently utilized as a renewable resource, it is important to develop a method to convert biomass into materials that can replace fossil fuel product. In this paper, eugenol, a bio-based allyl chain-substituted guaiacol, was used to synthesize self-healable copolymers. Eugenol terminated polyurethane prepolymer (ETPU) was synthesized from eugenol and polyurethane prepolymers terminated with isocyanate groups. ETPU contained two allyl groups. Self-healing copolymer networks were obtained by copolymerization of ETPU and styrene monomer via free radical polymerization. Effects of ETPU content on the properties of copolymers were then studied. These copolymers containing ETPU exhibited good thermal stability and mechanical properties. These copolymers showed higher tensile strength and elongation at break than PS. Their maximum tensile strength reached 19 MPa. In addition, these copolymers showed self-healing property at elevated temperature due to the reversible nature of urethane units in ETPU.

13.
ACS Omega ; 3(12): 18398-18410, 2018 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458412

RESUMO

We report for the first time that alkali carbonates (Li2CO3, K2CO3, and Rb2CO3) based on a low-temperature solution process can be used as interfacial modifiers for SnO2 as robust electron-transport layers (ETL) for inverted organic solar cells (iOSCs). The room-temperature photoluminescence, the electron-only devices, and the impedance studies altogether suggested the interfacial properties of the alkali carbonates-modified SnO2 ETLs, which were much better than those based on the SnO2 only, provided efficient charge transport, and reduced the charge recombination rates for iOSCs. The iOSCs using the polymer donor poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl] and the fullerene acceptor phenyl-C70-butyric acid methyl ester as the active layer showed the average power-conversion efficiencies (PCEs) based on ten devices of 6.70, 6.85, and 7.35% with Li2CO3-, K2CO3-, and Rb2CO3-modified SnO2 as ETLs, respectively; these are more than 22, 24, and 33% higher than those based on the SnO2 only (5.49%). Moreover, these iOSC devices exhibited long-term stabilities, with over 90% PCEs remaining after the devices were stored in ambient air for 6 weeks without encapsulations. We believe that alkali carbonates-modified SnO2 approaches are an effective way to achieve stable and highly efficient iOSCs and might also be suitable for other optoelectronic devices where an ETL is needed, such as perovskite solar cells or organic light-emitting diodes.

14.
ACS Appl Mater Interfaces ; 9(4): 3831-3841, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28029030

RESUMO

1-D ZnO represents a fascinating class of nanostructures that are significant to optoelectronics. In this work, we investigated the use of an eco-friendly, metal free in situ doping through a pure thiophene-sulfur (S) on low temperature processed (<95 °C) and annealed (<170 °C), planar 1-D ZnO nanorods (ZnRs) spin-coated as a hole-blocking and electron transporting layer (ETL) for inverted organic solar cells (iOSCs). The TEM, HRTEM, XPS, FT-IR, EDS and Raman studies clearly reveal that the thiophene-S (Thi-S) atom is incorporated on planar ZnRs. The investigations in electrical properties suggest the enhancement in conductivity after Thi-S doping on 1-D ZnRs. The iOSCs of poly(3-hexylthiophene-2,5-diyl) and phenyl-C61-butyric acid methyl ester (P3HT: PC60BM) photoactive layer containing thiophene-S doped planar ZnRs (Thi-S-PZnRs) as ETL exhibits power conversion efficiency (PCE) of 3.68% under simulated AM 1.5 G, 100 mW cm-2 illumination. The ∼47% enhancement in PCE compared with pristine planar ZnRs (PCE = 2.38%) ETL is attributed to a combination of desirable energy level alignment, morphological modification, increased conductivity and doping effect. The universality of Thi-S-PZnRs ETL is demonstrated by the highest PCE of 8.15% in contrast to 6.50% exhibited by the iOSCs of ZnRs ETL for the photoactive layer comprising of poly[4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b;4,5-b]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)]: phenyl-C71-butyric acid methyl ester (PTB7-Th: PCB71M). This enhancement in PCE is observed to be driven mainly through improved photovoltaic parameters like fill factor (ff) as well as photocurrent density (Jsc), which are assigned to increased conductivity, exciton dissociation, and effective charge extraction, while; better ohmic contact, reduced charge recombination, and low leakage current density resulted in increased Voc.

15.
ACS Appl Mater Interfaces ; 9(2): 1645-1653, 2017 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-27982562

RESUMO

SnO2 recently has attracted particular attention as a powerful buffer layer for organic optoelectronic devices due to its outstanding properties such as high electron mobility, suitable band alignment, and high optical transparency. Here, we report on facile low-temperature solution-processed SnO2 nanoparticles (NPs) in applications for a cathode buffer layer (CBL) of inverted organic solar cells (iOSCs). The conduction band energy of SnO2 NPs estimated by ultraviolet photoelectron spectroscopy was 4.01 eV, a salient feature that is necessary for an appropriate CBL. Using SnO2 NPs as CBL derived from a 0.1 M precursor concentration, P3HT:PC60BM-based iOSCs showed the best power conversion efficiency (PCE) of 2.9%. The iOSC devices using SnO2 NPs as CBL revealed excellent long-term device stabilities, and the PCE was retained at ∼95% of its initial value after 10 weeks in ambient air. These solution-processed SnO2 NPs are considered to be suitable for the low-cost, high throughput roll-to-roll process on a flexible substrate for optoelectronic devices.

16.
ACS Appl Mater Interfaces ; 8(51): 35270-35280, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-27976842

RESUMO

The issue of work-function and surface energy is fundamental to "decode" the critical inorganic/organic interface in hybrid organic photovoltaics, which influences important photovoltaic events like exciton dissociation, charge transfer, photocurrent (Jsc), open-circuit voltage (Voc), etc. We demonstrate that by incorporating an interlayer of cyanoacrylic acid small molecular layer (SML) on solution-processed, spin-coated, planar ZnO nanorods (P-ZnO NRs), higher photovoltaic (PV) performances were achieved in both inverted organic photovoltaic (iOPV) and hybrid organic photovoltaic (HOPV) devices, where ZnO acts as an "electron-transporting layer" and as an "electron acceptor", respectively. For the tuned range of surface energy from 52.5 to 33 mN/m, the power conversion efficiency (PCE) in bulk heterojunction (BHJ) iOPVs based on poly(3-hexylthiophene) (P3HT) and phenyl-C60-butyric acid methyl ester (PC60BM) increases from 3.16% to 3.68%, and that based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene)-2-carboxylate-2-6-diyl)] (PTB7:Th):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) photoactive BHJ increases from 6.55% to 8.0%, respectively. The improved PV performance in iOPV devices is majorly attributed to enhanced photocurrents achieved as a result of reduced surface energy and greater electron affinity from the covalent attachment of the strong electron-withdrawing cyano moiety, while that in HOPV devices, where PCE increases from 0.21% to 0.79% for SML-modified devices, is ascribed to a large increase in Voc benefitted due to reduced work function effected from the presence of strong dipole moment in SML that points away from P-ZnO NRs.

17.
Nanoscale ; 8(9): 5024-36, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26864170

RESUMO

In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM-ZnO NRs) leads to higher aggregation owing to the weaker solubility of SMs in solutions of ZnO NRs dispersed in chlorobenzene (CB). A prior addition of organic 2-(2-methoxyethoxy)acetic acid (MEA) over ZnO NRs not only inhibits aggregation of SMs over ZnO NRs, but also provides enough sites for the SM to strongly couple with the ZnO NRs to yield transparent SM-MEA-ZnO NRs hybrids that exhibited excellent capability as electron transporting layers (ETLs) in inverted organic solar cells (iOSCs) of P3HT:PC60BM bulk-heterojunction (BHJ) photoactive layers. A strongly coupled SM-MEA-ZnO NR hybrid reduces the series resistance by enhancing the interfacial area and tunes the energy level alignment at the interface between the (indium-doped tin oxide, ITO) cathode and BHJ photoactive layers. A significant enhancement in power conversion efficiency (PCE) was achieved for iOSCs comprising ETLs of SM-MEA-ZnO NRs (3.64%) advancing from 0.9% for pristine ZnO NRs, while the iOSCs of aggregated SM-ZnO NRs ETL exhibited a much lower PCE of 2.6%, thus demonstrating the potential of the co-functionalization approach. The superiority of the co-functionalized SM-MEA-ZnO NRs ETL is also evident from the highest PCE of 7.38% obtained for the iOSCs comprising BHJ of PTB7-Th:PC60BM compared with extremely poor 0.05% for non-functionalized ZnO NRs.

18.
Gerontology ; 62(1): 81-5, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26461273

RESUMO

BACKGROUND: Although stereotype threat is a well-documented phenomenon, previous studies examining it in older adults have almost exclusively focused on objective cognitive outcomes. Considerably less attention has been paid to the impact of stereotype threat on older adults' subjective assessments of their own abilities or to the impact of stereotype threat in noncognitive domains. OBJECTIVE: Older adults are stereotyped as having experienced not only cognitive declines, but physical declines as well. The current study tested the prediction that stereotype threat can negatively influence older adults' subjective hearing abilities. METHODS: To test this, 115 adults (mean age 50.03 years, range 41-67) read either a positive or negative description about how aging affects hearing. All participants then answered a questionnaire in which they assessed their own hearing abilities. RESULTS: The impact of stereotype threat on self-reported hearing was moderated by chronological age. Participants in their 40s and early 50s were unaffected by the stereotype threat manipulation. In contrast, participants in their late 50s and 60s rated their hearing as being subjectively worse when under stereotype threat. CONCLUSION: The current study provides a clear demonstration that stereotype threat negatively impacts older adults' subjective assessments of their own abilities. It is also the first study to demonstrate an effect of stereotype threat within the domain of hearing. These results have important implications for researchers investigating age-related hearing decline. Stereotype threat can lead to overestimation of the prevalence of age-related hearing decline. It can also serve as a confounding variable when examining the psychosocial correlates of hearing loss. Because of this, researchers studying age-related hearing loss should aim to provide a stereotype threat-free testing environment and also include assessments of stereotype threat within their studies.


Assuntos
Envelhecimento/psicologia , Perda Auditiva/diagnóstico , Autorrelato , Estereotipagem , Adulto , Fatores Etários , Idoso , Feminino , Perda Auditiva/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
19.
ACS Appl Mater Interfaces ; 7(45): 25094-104, 2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26334564

RESUMO

Here we report functionalized multiwalled carbon nanotubes (f-MWCNTs)-CdSe nanocrystals (NCs) as photosensitizer in photoelectrochemical cells, where f-MWCNTs were uniformly coated with CdSe NCs onto SnO2 upright standing nanosheets by using a simple electrodeposition method. The resultant blended photoanodes demonstrate extraordinary electrochemical properties including higher Stern-Volmer constant, higher absorbance, and positive quenching, etc., caused by more accessibility of CdSe NCs compared with pristine SnO2-CdSe photoanode. Atomic and weight percent changes of carbon with f-MWCNTs blending concentrations were confirmed from the energy dispersive X-ray analysis. The morphology images show a uniform coverage of CdSe NCs over f-MWCNTs forming a core-shell type structure as a blend. Compared to pristine CdSe, photoanode with f-MWCNTs demonstrated a 257% increase in overall power conversion efficiency. Obtained results were corroborated by the electrochemical impedance analysis. Higher scattering, more accessibility, and hierarchical structure of SnO2-f-MWCNTs-blend-CdSe NCs photoanode is responsible for higher (a) electron mobility (6.89 × 10(-4) to 10.89 × 10(-4) cm(2) V(-1) S(1-)), (b) diffusion length (27 × 10(-6)),

20.
Opt Express ; 23(7): A211-8, 2015 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-25968787

RESUMO

Localized surface plasmon mediated polymer solar cells (PSCs) were fabricated using the Ag/SiO(2) nanoparticles (NPs). The inverted PSC structure without poly (3,4-ethylenedioxythiophene) polystyrene sulfonate ( PEDOT: PSS) was prepared due to the efficient insertion of Ag/SiO(2) NPs in the vicinity of active layer, which led to an enhancement in photo-conversion efficiency (PCE). This enhancement mainly comes from the light scattering by the SiO(2) shell and the localized surface plasmon effect by the Ag core, but we also considered the structural issues such as the NP distribution, the swelling of the active layer and of the metal electrode.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...