科研成果

The electron-transporting material (ETM) is one of the key factors to determine the efficiency and stability of organic light-emitting diodes (OLEDs). A novel ETM with a ``(Acceptor)(n)-Donor-(Acceptor)(n)'' (''(A)(n)-D-(A)(n)'') structure, 2,7-di([2,2:6,2-terpyridin]-4-yl)-9,9-spirobifluorene (27-TPSF), is synthesized by combining electron-withdrawing terpyridine (TPY) moieties and rigid twisted spirobifluorene, in which the TPY moieties facilitate electron transport and injection while the spirobifluorene moiety ensures high triplet energy (T-1 = 2.5 eV) as well as enhances glass transition temperature (T-g = 195 degrees C) for better stability. By using tris[2-(p-tolyl)pyridine]iridium(III) (Ir(mppy)(3)) as the emitter, the 27-TPSF-based device exhibits a maximum external quantum efficiency (eta(ext, max)) of 24.5%, and a half-life (T-50) of 121, 6804, and 382 636 h at an initial luminance of 10 000, 1000, and 100 cd m(-2), respectively, which are much better than the commercialized ETM of 9,10-bis(6-phenylpyridin-3-yl)anthracene (DPPyA). Furthermore, a higher efficiency, a eta(ext, max) of 28.2% and a maximum power efficiency (eta(PE), (max)) of 129.3 lm W-1, can be achieved by adopting bis(2- phenylpyridine)iridium(III)(2,2,6,6-tetramethylheptane-3,5-diketonate) (Ir(ppy)(2)tmd) as the emitter and 27-TPSF as the ETM. These results indicate that the derivative of TPY to form (A)(n)-D-(A)(n) structure is a promising way to design an ETM with good comprehensive properties for OLEDs.

In this letter, we demonstrate a recessed-anode Schottky barrier diode (SBD) on a double AlGaN/GaN heterojunction structure. A self-terminated, oxidation/wet etching with low-pressure chemical vapor deposition (LPCVD) Si3N4 mask is applied in the anode recess process. Unlike common plasma-based, dry etching techniques, the etched surface is not subjected to ion bombardment, and the etch depth is precisely controlled. As a result, a high effective channel mobility of 1079 cm2/V . s is maintained in the channel beneath the recess surface. The fabricated devices with a 15-mum anode-to-cathode distance (LAC) are found to exhibit a uniform, low turn-ON voltage (VON) of 0.69 +or- 0.03 V, and a low specific on-resistance (RON,SP) of 2.83 mQ . cm2. The SBDs also show excellent off-state blocking characteristics due to the smooth recess interface together with the assistance of LPCVD grown Si3N4. A breakdown voltage of 1190 V is achieved for the SBDs with 15-mum LAC at a leakage current criteria of 1 muA/mm, and the Baliga's figure-of-merit is 500 MW/cm2.

Compelling evidence indicates that lipid metabolism is in partial control of the circadian system. In this context, it has been reported that the melatonin receptor 1B (MTNR1B) genetic variant influences the dynamics of melatonin secretion, which is involved in the circadian system as a chronobiotic. The objective was to analyze whether the MTNR1B rs10830963 genetic variant was related to changes in lipid levels in response to dietary interventions with different macronutrient distribution in 722 overweight/obese subjects from the POUNDS Lost trial. We did not find a significant association between the MTNR1B genotype and changes in lipid metabolism. However, dietary fat intake significantly modified genetic effects on 2 year changes in total and LDL cholesterol (P interaction = 0.006 and 0.001, respectively). In the low-fat diet group, carriers of the sleep disruption G allele (minor allele) showed a greater reduction of total cholesterol (beta +/- SE = -5.78 +/- 2.88 mg/dl, P = 0.04) and LDL cholesterol (beta +/- SE = -7.19 +/- 2.37 mg/dl, P = 0.003). Conversely, in the high-fat diet group, subjects carrying the G allele evidenced a smaller decrease in total cholesterol (beta +/- SE = 5.81 +/- 2.65 mg/dl, P = 0.03) and LDL cholesterol (beta +/- SE = 5.23 +/- 2.21 mg/dl, P = 0.002). Subjects carrying the G allele of the circadian rhythm-related MTNR1B variant may present a bigger impact on total and LDL cholesterol when undertaking an energy-restricted low-fat diet.

A composite comprises a carbonaceous and a metallic nanotube conjugated with a carbonaceous support. The composite may be used to remove contaminants from water.

BACKGROUND: Observational studies have illustrated that maternal central obesity is associated with birth size, including of birth weight, birth length and head circumference, but the causal nature of these associations remains unclear. Our study aimed to test the causal effect of maternal central obesity on birth size and puberty height growth using a Mendelian randomization (MR) analysis. METHODS: We performed two-sample MR using summary-level genome-wide public data. Thirty-five single nucleotide polymorphisms (SNPs), 25 SNPs and 41 SNPs were selected as instrumental variables for waist-to-hip ratio adjusted for BMI, waist circumference adjusted for BMI and hip circumference adjusted for BMI, respectively to test the causal effects of maternal central obesity on birth size and puberty height using an inverse-variance-weighted approach. RESULTS: In this MR analysis, we found no evidence of a causal association between waist circumference or waist-to-hip ratio and the outcomes. However, we observed that one standard deviation (SD) increase in hip circumference (HIP) was associated with a 0.392 SD increase in birth length (p = 1.1 x 10(- 6)) and a 0.168 SD increase in birth weight (p = 7.1 x 10(- 5)), respectively at the Bonferroni-adjusted level of significance. In addition, higher genetically predicted maternal HIP was strongly associated with the puberty heights (0.835 SD, p = 8.4 x 10(- 10)). However, HIP was not associated with head circumference (p = 0.172). CONCLUSIONS: A genetic predisposition to higher maternal HIP was causally associated with larger offspring birth size independent of maternal BMI. However, we found no evidence of a causal association between maternal waist circumference, waist-to-hip ratio and birth size.