ER/AR Multi-Conformational Docking Server: A Tool for Discovering and Studying Estrogen and Androgen Receptor Modulators.

The prediction of the estrogen receptor (ER) and androgen receptor (AR) activity of a compound is quite important to avoid the environmental exposures of endocrine-disrupting chemicals. The Estrogen and Androgen Receptor Database (EARDB, http://eardb.schanglab.org.cn/) provides a unique collection of reported ERα, ERß, or AR protein structures and known small molecule modulators. With the user-uploaded query molecules, molecular docking based on multi-conformations of a single target will be performed. Moreover, the 2D similarity search against known modulators is also provided. Molecules predicted with a low binding energy or high similarity to known ERα, ERß, or AR modulators may be potential endocrine-disrupting chemicals or new modulators. The server provides a tool to predict the endocrine activity for compounds of interests, benefiting for the ER and AR drug design and endocrine-disrupting chemical identification.

Circularly Polarized Thermally Activated Delayed Fluorescence Emitters in Through-Space Charge Transfer on Asymmetric Spiro Skeletons.

This work describes a strategy to produce circularly polarized thermally activated delayed fluorescence (CP-TADF). A set of two structurally similar organic emitters SFST and SFOT are constructed, whose spiro architectures containing asymmetric donors result in chirality. Upon grafting within the spiro frameworks, the donor and acceptor are fixed proximally in a face-to-face manner. This orientation allows intramolecular through-space charge transfer (TSCT) to occur in both emitters, leading to TADF properties. The donor units in SFST and SFOT have a sulfur and oxygen atom, respectively; such a subtle difference has great impacts on their photophysical, chiroptical, and electroluminescence (EL) properties. SFOT exhibits greatly enhanced EL performance in doped organic light-emitting diodes, with external quantum efficiency (EQE) up to 23.1%, owing to the concurrent manipulation of highly photoluminescent quantum efficiency (PLQY, ∼90%) and high exciton utilization. As a comparison, the relatively larger sulfur atom in SFST introduces heavy atom effects and leads to distortion of the molecular backbone that lengthens the donor-acceptor distance. SFST thus has lower PLQY and faster nonradiative decay rate. The collective consequence is that the EQE value of SFST, i.e., 12.5%, is much lower than that of SFOT. The chirality of these two spiro emitters results in circularly polarized luminescence. Because SFST has a more distorted molecular architecture than SFOT, the luminescence dissymmetry factor (|glum|) of circularly polarized luminescence of one enantiomer of the former, namely, either (S)-SFST or (R)-SFST, is almost twice that of (S)-SFOT/(R)-SFOT. Moreover, the CP organic light-emitting diodes (CP-OLEDs) show obvious circularly polarized electroluminescence (CPEL) signals with gEL of 1.30 × 10-3 and 1.0 × 10-3 for (S)-SFST and (S)-SFOT, respectively.

Highly Efficient Thermally Activated Delayed Fluorescence via an Unconjugated Donor-Acceptor System Realizing EQE of Over 30.

In this work, two novel thermally activated delayed fluorescence (TADF) emitters, 2tDMG and 3tDMG, are synthesized for high-efficiency organic light-emitting diodes (OLEDs), The two emitters have a tilted face-to-face alignment of donor (D)/acceptor (A) units presenting intramolecular noncovalent interactions. The two TADF materials are deposited either by an evaporation-process or by a solution-process, both of them leading to high OLED performance. 2tDMG used as the emitter in evaporation-processed OLEDs achieves a high external quantum efficiency (EQE) of 30.8% with a very flat efficiency roll-off of 7% at 1000 cd m-2 . The solution-processed OLEDs also display an interesting EQE of 16.2%. 3tDMG shows improved solubility and solution processability as compared to 2tDMG, and thus a high EQE of 20.2% in solution-processed OLEDs is recorded. The corresponding evaporation-processed OLEDs also reach a reasonably high EQE of 26.3%. Encouragingly, this work provides a novel strategy to address the imperious demands for OLEDs with high EQE and low roll-off.

Sky-Blue Thermally Activated Delayed Fluorescence with Intramolecular Spatial Charge Transfer Based on a Dibenzothiophene Sulfone Emitter.

Intramolecular spatial charge transfer (ISCT) plays a critical role in determining the optical and charge transport properties of thermally activated delayed fluorescence (TADF) materials. Herein, a new donor/acceptor-type TADF compound based on rigid dibenzothiophene sulfone (DBTS) moiety, STF-DBTS, was designed and synthesized. Fluorene unit was used as a rigid linker to position the rigid acceptor and donor subunit in close vicinity with control over their spacing and molecular structure and to achieve high photoluminescence quantum yield (∼53%) and TADF property. For comparison purposes, we constructed the more flexible STF-DPS with a less rotationally constrained diphenylsulphone (DPS) acceptor instead of the rigid DBTS units, and STF-DPS showed no TADF properties and lower PLQY (16.0%). Organic light-emitting diodes (OLEDs) based on STF-DBTS achieve an external quantum efficiency (EQE) of 10.3% at 488 nm, which is a fivefold improvement in EQE with respect to STF-DPS.

Highly efficient luminescence from space-confined charge-transfer emitters.

Charge-transfer (CT) complexes, formed by electron transfer from a donor to an acceptor, play a crucial role in organic semiconductors. Excited-state CT complexes, termed exciplexes, harness both singlet and triplet excitons for light emission, and are thus useful for organic light-emitting diodes (OLEDs). However, present exciplex emitters often suffer from low photoluminescence quantum efficiencies (PLQEs), due to limited control over the relative orientation, electronic coupling and non-radiative recombination channels of the donor and acceptor subunits. Here, we use a rigid linker to control the spacing and relative orientation of the donor and acceptor subunits, as demonstrated with a series of intramolecular exciplex emitters based on 10-phenyl-9,10-dihydroacridine and 2,4,6-triphenyl-1,3,5-triazine. Sky-blue OLEDs employing one of these emitters achieve an external quantum efficiency (EQE) of 27.4% at 67 cd m-2 with only minor efficiency roll-off (EQE = 24.4%) at a higher luminous intensity of 1,000 cd m-2. As a control experiment, devices using chemically and structurally related but less rigid emitters reach substantially lower EQEs. These design rules are transferrable to other donor/acceptor combinations, which will allow further tuning of emission colour and other key optoelectronic properties.

Design and Synthesis of Donor-σ-π-σ-Acceptor-Type Dispiro Molecules.

Two novel donor-σ-π-σ-acceptor-type dispiro molecules-10-phenyl-10H-dispiro-acridine-9,9'-anthracene-10',9''-fluorene-2'',7''-dicarbo-nitrile (DiSAAF) and dispiro-fluorene-9,9'-anthracene-10',9''-quinolino[3,2,1-kl]phenoxazine-2,7-dicarbonitrile (DiSFAQ)-with excellent thermal stability are designed and synthesized. Both materials exhibit blocked long-range intramolecular charge transfer but show intermolecular charge-transfer emission in the film state. Their photophysical and thermal properties then are fully investigated and a maximum external quantum efficiency of 21.7% of the red phosphorescent device is achieved by DiSAAF.

C1-Linked Spirobifluorene Dimers: Pure Hydrocarbon Hosts for High-Performance Blue Phosphorescent OLEDs.

Reported here are C1-linked spiro-bifluorene dimers. A comprehensive study is carried out to analyze the electronic properties of these highly twisted structures. This work shows that the C1-position enables the design of pure hydrocarbon materials, with a high triplet energy, for hosting blue phosphors in efficient phosphorescent OLEDs (PhOLEDs). To date, this work describes the highest performance of blue PhOLEDs ever reported for pure hydrocarbons (external quantum efficiency of ca. 23 %), thus highlighting the potential of the C1-spirobifluorene scaffold in organic electronics.

High-Efficiency White Organic Light-Emitting Diodes Integrating Gradient Exciplex Allocation System and Novel D-Spiro-A Materials.

How to maintain high power efficiency (PE) and color stability under operating brightness is critical for the white organic light-emitting diodes (WOLEDs). To this end, two novel spiro-type materials STPy3 and STPy4 were designed. These materials could act as a single host and achieve a remarkable external quantum efficiency of 27.5% at 1000 cd m-2; to further optimize the PEs of OLEDs, STPy3/4 and PO-T2T were used as co-host-induced exciplexes, which enhanced the PE of green OLED to over 148.0 lm W-1. Unfortunately, the lower triplet energy level of exciplexes than blue emitters implied it is commonly unsuitable to fabricate WOLEDs. Herein, a new allocation of gradient exciplex (AGE) strategy was developed in which the formed excitons could be rationally allocated in a consequently doped nonuniform profile. The AGE incorporated the advantages of the exciplex with an ultralow turn-on voltage of 2.3 V and efficiency stability of spiro materials. The PE at 1000 cd m-2 was enhanced to 72.7 lm W-1, representing the first exciplex WOLED with the performance exceeding that of conventional fluorescent tubes.

[Effects of a Tribasic Amendment on Cadmium and Arsenic Accumulation and Translocation in Rice in a Field Experiment].

An in-situ paddy field experiment was carried out to study the influence of a tribasic amendment (QFJ, hydroxyapatite+zeolite+biochar) on Cd and As accumulation and translocation in rice grown in soil contaminated with cadmium and arsenic, with the concentrations of soil Cd and As being 3.58 mg·kg-1 and 124.79 mg·kg-1, respectively. The results showed that, after application of QFJ, the pH, CEC, and OM contents of the rice rhizosphere soil tended to increase. The exchangeable concentrations of Cd and As were reduced from 0.37 mg·kg-1 and 0.07 mg·kg-1 to 0.12 mg·kg-1 and 0.04 mg·kg-1, respectively. The concentrations of Cd and As in rice tissues decreased after in-situ restoration. When 9.00 t·hm-2 of QFJ was applied, the Cd concentration in brown rice was reduced from 0.46 to 0.18 mg·kg-1, and that of inorganic As was reduced from 0.25 to 0.16 mg·kg-1, both lower than 0.2 mg·kg-1, meeting the requirement set by the National Food Standards (GB 2762-2012). QFJ application decreased the Cd and As bioaccumulation capacity of the roots and decreased the rice plant's capacity of Cd translocation quantity from the underground parts to the aerial parts; at same time, the Cd transferring capacity of the roots and the As transferring capacity in straw and husk were also decreased.

Protective effects on mitochondria and anti-aging activity of polysaccharides from cultivated fruiting bodies of Cordyceps militaris.

Cordyceps militaris (L.) Link is an entomopathogenic fungus parasitic to Lepidoptera larvae, and is widely used as a folk tonic or invigorant for longevity in China. Although C. militaris has been used in traditional Chinese medicine for millennia, there is still a lack convincing evidence for its anti-aging activities. This study was performed to investigate the effects of polysaccharides from cultivated fruiting bodies of C. militaris (CMP) on mitochondrial injury, antioxidation and anti-aging activity. Fruiting bodies of C. militaris were cultivated artificially under optimized conditions. The spectrophotometric method was used to measure thiobarbituric acid reactive substances (TBARS), mitochondrial swelling, and activities of scavenging superoxide anions in vitro. D-galactose (100 mg/kg/day) was injected subcutaneously into back of the neck of mice for 7 weeks to induce an aging model. The effects of CMP on the activities of catalase (CAT), surperoxide dismutase (SOD), glutathione peroxidase (GPx) and anti-hydroxyl radicals were assayed in vivo using commercial monitoring kits. The results showed that CMP could inhibit mitochondrial injury and swelling induced by Fe²(+)-L-Cysteine in a concentration- dependent manner and it also had a significant superoxide anion scavenging effect. Moreover, the activities of CAT, SOD, GPx and anti-hydroxyl radicals in mice liver were increased significantly by CMP. These results indicate that CMP protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting mitochondrial swelling, and increasing the activities of antioxidases. Therefore, CMP may have pharmaceutical values for mitochondrial protection and anti-aging. CMP was the major bioactive component in C. militaris.

Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography.

By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C(8)MIM][PF(6)] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH(2)PO(4) with 2M Na(2)SO(4); acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100microg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.