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1.
Artigo em Inglês | MEDLINE | ID: mdl-32266807

RESUMO

For light-emitting polymers with a deep highest occupied molecular orbital energy level used for polymer light-emitting diodes (PLEDs), the hole injection barrier and hole transport of the anode buffer layer are of vital importance for optimizing electroluminescent performance. In this study, high-work-function hole injection layers with nanotextures were achieved by modifying poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with a perfluorinated ionomer (PFI) and n-butyl alcohol and were used to achieve a single-layer device without a hole transport layer. With such an interlayer, the PLEDs based on PPF-SO25 exhibit remarkable current efficiency over 13.0 cd A-1, which significantly outperform the devices with regular PEDOT:PSS. To our knowledge, this performance is among the best reported for single-layer blue PLEDs. The bias-dependent capacitance curves of these PLEDs suggest a nonuniform surface distribution of PFI. Our findings show that the PFI-modified PEDOT:PSS not only operates as a high-work-function hole injection layer to facilitate hole injection but also as a potential inner scattering medium for light extraction.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32000485

RESUMO

Blue light-emitting polymers are in urgent demand for new-generation display and solid-state lighting devices fabricated through low-cost wet processing. However, their current performances are far from satisfactory. Here, we developed a series of poly(fluorene-co-dibenzothiophene-S,S-dioxides) (PFSOs) bearing different alkyl chains, alkoxyphenyl chains, or both alkylaryl and alkoxyphenyl side chains. The introduction of alkoxyphenyl groups moderately enhanced the electron-donating ability of the polymers, leading to more balanced charge carrier fluxes. Meanwhile, asymmetric bulky side chains enabled more pronounced variation of molecular conformation while restraining the intermolecular aggregation of polymers, resulting in a lower refractive index, thus facilitating light extraction compared with polymers based on the same two alkyl or alkoxyphenyl side chains. Polymer light-emitting devices based on PFSO-BMD with asymmetric side chains exhibited a maximum luminous efficiency of 8.58 cd A-1, associated with pure blue Commission Internationale de l'Eclairage coordinates of (0.14, 0.14). These findings demonstrated that side-chain modification can be an effective strategy for developing efficient solution-processable blue light-emitting polymers.

3.
PLoS One ; 14(5): e0217575, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31141568

RESUMO

PURPOSE: The impact of diurnal unsymmetrical rise in temperature on soil respiration (Rs) is not fully understood; thus, we explored such a warming influence on Rs in an agroecological system of the Lhasa. MATERIALS AND METHODS: A field warming experiment (C: control; DW: daytime warming; NW: nighttime warming; DW+NW: daytime plus nighttime warming) was carried out in a naked barley ecological system. RESULTS AND DISCUSSION: The DW, NW and DW+NW treatments dramatically increased soil temperature and decreased soil moisture but did not markedly modify Rs. The effects of DW and NW on soil respiration sensitivity (Q10) during the daytime and nighttime were different; they had no effects on daytime Q10 of Rs, but a significant inhibitory effect on nighttime Q10 of Rs. CONCLUSIONS: A diurnal unsymmetrical rise in temperature brought about different results for the Q10 of Rs but did not cause changes in Rs under different experimental treatments in agroecological systems of the Lhasa.


Assuntos
Ecossistema , Temperatura Alta , Estações do Ano , Solo , China
4.
ACS Appl Mater Interfaces ; 11(15): 14208-14214, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30908001

RESUMO

To achieve high detectivity in all-polymer photodetectors (all-PPDs), a thick-film photoactive layer is favored because it can effectively suppress the dark current density. However, if the photoactive layer of the film is too thick, it leads to reduced responsivity owing to increased recombination loss. We developed high-performance all-PPDs by using a narrowband-gap p-type polymer NT40 and an n-type polymer poly{[ N, N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5,5'-(2,2'bithiophene)} as the photoactive layer. The high charge carrier mobility of both copolymers enabled a photoactive layer thickness of 300 nm, leading to an ultralow dark current density of 4.85 × 10-10 A cm-2, a detectivity of 2.61 × 1013 Jones, a high responsivity of 0.33 A W-1 at 720 nm, and a bias of -0.1 V. The detectivity achieved >1013 Jones in a wide range from 360 to 850 nm, which is among the highest values so far reported for all-PPDs without extra gains. More importantly, the resultant all-PPDs exhibited a high working frequency over 10 kHz associated with a large linear dynamic range. These findings demonstrate great potential for practical applications of the all-PPDs developed in this work.

5.
ACS Appl Mater Interfaces ; 11(8): 8350-8356, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30697994

RESUMO

The ideal bulk-heterojunction for high-performance organic photodetectors prefers a morphology with a vertically gradient component to suppress the leaking current. Here, we demonstrate an all-polymer photodetector with a segregated bulk-heterojunction active layer. This all-polymer photodetector exhibits a dramatically reduced dark current density because of its built-in charge blocking layer, with a responsivity of 0.25 A W-1 at a wavelength of approximately 600 nm and specific detectivity of 5.68 × 1012 cm Hz1/2 W-1 as calculated from the noise spectra at 1 kHz. To our knowledge, this is among the best performances reported for photodetectors based on both polymeric donor and acceptor in the photoactive layer. These findings present a facile approach to improving the specific detectivity of polymer photodetectors via a layer-by-layer solution process.

6.
Int J Mol Sci ; 19(12)2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-30469474

RESUMO

The paired-box 3 (Pax3) is a transcription factor and it plays an important part in melanin synthesis. In this study, a new Pax3 gene was identified from Pteria penguin (Röding, 1798) (P. penguin) by RACE-PCR (rapid-amplification of cDNA ends-polymerase chain reaction) and its effect on melanin synthesis was deliberated by RNA interference (RNAi). The cDNA of PpPax3 was 2250 bp long, containing an open reading fragment of 1365 bp encoding 455 amino acids. Amino acid alignment and phylogenetic tree showed PpPax3 shared the highest (69.2%) identity with Pax3 of Mizuhopecten yessoensis. Tissue expression profile showed that PpPax3 had the highest expression in mantle, a nacre-formation related tissue. The PpPax3 silencing significantly inhibited the expression of PpPax3, PpMitf, PpTyr and PpCdk2, genes involved in Tyr-mediated melanin synthesis, but had no effect on PpCreb2 and an increase effect on PpBcl2. Furthermore, the PpPax3 knockdown obviously decreased the tyrosinase activity, the total content of eumelanin and the proportion of PDCA (pyrrole-2,3-dicarboxylic acid) in eumelanin, consistent with influence of tyrosinase (Tyr) knockdown. These data indicated that PpPax3 played an important regulating role in melanin synthesis by Tyr pathway in P. penguin.


Assuntos
Melaninas/biossíntese , Monofenol Mono-Oxigenase/metabolismo , Ostreidae/metabolismo , Fator de Transcrição PAX3/metabolismo , Animais , Ostreidae/genética , Fator de Transcrição PAX3/genética
7.
ACS Appl Mater Interfaces ; 8(39): 26162-26168, 2016 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-27608850

RESUMO

Inkjet printing has been considered an available way to achieve large size full-color RGB quantum dots LED display, and the key point is to obtain printed film with uniform and flat surface profile. In this work, mixed solvent of 20 vol % 1,2-dichlorobenzene (oDCB) with cyclohexylbenzene (CHB) was used to dissolve green quantum dots (QDs) with CdSe@ZnS/ZnS core/shell structure. Then, by inkjet printing, a flat dotlike QDs film without the coffee ring was successfully obtained on polyetherimide (PEI)-modified ZnO layer, and the printed dots array exhibited great stability and repeatability. Here, adding oDCB into CHB solutions was used to reduce surface tension, and employing ZnO nanoparticle layer with PEI-modified was used to increase the surface free energy. As a result, a small contact angle is formed, which leads to the enhancement of evaporation rate, and then the coffee ring effect was suppressed. The printed dots with flat surface profile were eventually realized. Moreover, inverted green QD-LEDs with PEI-modified ZnO film as electron transport layer (ETL) and printed green QDs film as emission layer were successfully fabricated. The QD-LEDs exhibited the maximum luminance of 12 000 cd/m2 and the peak current efficiency of 4.5 cd/A at luminance of 1500 cd/m2.

8.
ACS Appl Mater Interfaces ; 8(31): 20237-42, 2016 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-27435357

RESUMO

Polymer light-emitting diodes (PLEDs) have attracted broad interest due to their solution-processable properties. It is well-known that to achieve better performance, organic light-emitting diodes require multilayer device structures. However, it is difficult to realize multilayer device structures by solution processing for PLEDs. Because most semiconducting polymers have similar solubility in common organic solvents, such as toluene, xylene, chloroform, and chlorobenzene, the deposition of multilayers can cause layers to mix together and damage each layer. Herein, a novel semiorthogonal solubility relationship was developed and demonstrated. For the first time, an alkane-soluble dendrimer is utilized as the electron-transport layer (ETL) in PLEDs via a solution-based process. With the dendrimer ETL, the external quantum efficiency increases more than threefold. This improvement in the device performance is attributed to better exciton confinement, improved exciton energy transfer, and better charge carrier balance. The semiorthogonal solubility provided by alkane offers another process dimension in PLEDs. By combining them with water/alcohol-soluble polyelectrolytes, more exquisite multilayer devices can be fabricated to achieve high device performance, and new device structures can be designed and realized.

9.
Springerplus ; 5: 137, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26933635

RESUMO

Highland barley is an important dominant crop in the Tibet and the croplands of the Tibet are experiencing obvious climatic warming. However, information about how soil respiration will respond to climatic warming in the highland barley system is still lacking. A field warming experiment using infrared heaters with two warming magnitudes was conducted in a highland barley system of the Tibet in May 2014. Five daily cycles of soil respiration was measured using a CO2 flux system (Li-8100, Li-COR Biosciences, Lincoln, NE, USA) during the period from early June to early September in 2014. The high and low experimental warming significantly increased soil temperature by 1.98 and 1.52 °C over the whole study period, respectively. The high experimental warming significantly decreased soil moisture. Soil respiration and its temperature sensitivity did not significantly change under both the high and low experimental warming. The response of soil respiration to experimental warming did not linearly correlate with warming magnitudes because a greater experimental warming resulted in a higher soil drying. Our findings suggested that clarifying the response of soil CO2 production and its temperature sensitivity to climatic warming need consider water availability in the highland barley system of the Tibet.

10.
Artigo em Chinês | MEDLINE | ID: mdl-25916527

RESUMO

OBJECTIVE: To investigate a reliable and easy assessment method for swallowing function by evaluating objectively the recovery process of swallowing function in patients six months after supracricoid partial laryngectomy. METHODS: The swallowing function of patients who underwent supracricoid partial laryngectomy was evaluated six months after operation in Nanfang Hospital of Southern Medical University between January 2013 and February 2014 with two methods, the modified barium swallow (MBS) and fiberoptic endoscopic evaluation of swallowing (FEES), combined with modified penetration aspiration scale (MPAS). Furthermore, the feasibility, reliability and accuracy of these two methods were compared. RESULTS: Eleven patients were enrolled. MPAS equals score 1 for solid food, semiliquid food, and liquid food was defined as a criteria of normal swallowing function. By MBS evaluation, the numbers of patients with normal swallowing function were two cases at day 16-30 postoperation, two cases at day 31-45 postoperation, five cases at day 46-90 postoperation, and six cases at day 91-180 postoperation, respectively. By FEES evaluation, the above numbers were three cases, four cases, six cases and eight cases, respectively. When the aspiration was minimal and ejected completely and MPAS was less than or equal to score 4 for solid food, semiliquid food, and liquid food, the gastric tube could be removed. According to this standard, the gastric tube was removed in all cases, and the mean time was (21.7 ± 9.8) days. A good correlation was obtained between these two methods when evaluating solid and semiliquid food, and the Kappa values were 0.802 and 0.844, respectively. However, a little agreement was obtained between these two methods when evaluating liquid food, and the Kappa value was 0.529. CONCLUSIONS: Patients who underwent supracricoid partial laryngectomy could restore good swallowing function in six months after the operation. Both the MBS and FEES are valuable procedures for evaluating objectively the swallowing function in patients after supracricoid partial laryngectomy. The FEES is much better than MBS, because FEES is a simple operation performed alone by otolaryngologists with no radiation.


Assuntos
Transtornos de Deglutição/cirurgia , Deglutição/fisiologia , Laringectomia , Endoscopia , Feminino , Humanos , Período Pós-Operatório , Reprodutibilidade dos Testes
11.
ACS Appl Mater Interfaces ; 6(11): 8345-52, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24840940

RESUMO

Highly efficient, solution-processed, and all fluorescent white organic light-emitting diodes (WOLEDs) based on fluorescent small molecules have been achieved by incorporating a low-conductivity hole injection layer and an inorganic-organic hybrid electron injection layer. The light-emission layer is created by doping a fluorescent π-conjugated blue dendrimer host (the zeroth generation dendrimer, G0) with a yellow-emitting fluorescent dopant oligo(paraphenylenevinylene) derivative CN-DPASDB with a doping ratio of 100:0.15 (G0:CN-DPASDB) by weight. To suppress excessive holes, the high-conductivity hole injection layer (PEDOT:PSS AI 4083) is replaced by the low-conductivity PEDOT:PSS CH 8000. To facilitate the electron injection, a hybrid electron injection layer is introduced by doping a methanol/water-soluble conjugated polymer poly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFNR2) with solution-processed cesium fluoride (CsF). The device achieves a maximum luminous efficiency of 17.0 cd A(-1) and a peak power efficiency of 15.6 lm W(-1) at (0.32, 0.37) with a color rendering index of 64.

12.
BBA Clin ; 2: 88-93, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26673151

RESUMO

BACKGROUND: Positivity of plasma Epstein-Barr virus (EBV)-DNA or serum virus capsid antigen-specific IgA (VCA-IgA) is a biomarker for the prognosis of nasopharyngeal carcinoma (NPC). The objective of this study was to determine the value of positivity for plasma EBV-DNA and/or VCA-IgA in predicting the survival of patients with NPC. METHODS: Plasma EBV-DNA and serum VCA-IgA in 506 NPC patients in this retrospective study were detected by quantitative real time polymerase chain reaction and enzyme-linked immunoabsorbent assay, respectively. The value of positivity for EBV-DNA and/or VCA-IgA in predicting the survival of patients with NPC was analyzed. RESULTS: Patients with positivity for both EBV-DNA and VCA-IgA had significantly shorter periods of relapse free survival (RFS) and overall survival (OS) than those with positive single measure or negative for both measures, and patients with positive single measure had significantly shorter periods of RFS and OS than those with negative for both. Multivariate analysis indicated that the positivity for EBV-DNA and/or VCA-IgA were significant risk factors for shorter periods of RFS and OS. CONCLUSION: These data indicated that positivity for both EBV-DNA and VCA-IgA was a better biomarker for the prognosis of patients with NPC. Our findings may provide new references for clinical practice.

13.
Ying Yong Sheng Tai Xue Bao ; 24(12): 3399-406, 2013 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-24697057

RESUMO

The distribution characteristics of soil N/P ratio in alpine grassland ecosystem of Qinghai-Tibet Plateau were surveyed by field investigation and laboratory analysis. Horizontally, soil N/ P ratio was generally higher in west and lower in east in a manner of staggered patch distribution, with higher N/P ratios mainly centralized in the hinterland of northern part of Tibet Plateau and in the lake basin area of the northern foot of Himalayas. Significant differences in soil N/P ratio were observed among grassland types and natural transects. Vertically, the distribution of N/P ratio along the soil profile from aboveground to underground among different grass types could be categorized into five patterns, including low-high-low-high, low-high-low, low-high, high-low-high-low, and high-low-high. The N/P ratio showed a significant positive correlation with soil bulk density at 0-20 cm depth, soil water content at 20-30 cm depth, contents of soil available K and total nitrogen, respectively. However, it showed significant negative correlation with soil bulk density at 20-30 cm depth, contents of soil available P and total P, respectively.


Assuntos
Pradaria , Nitrogênio/análise , Fósforo/análise , Solo/química , China , Poaceae
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