Purely organic electroluminescent materials, such as thermally activated delayed fluorescent (TADF) and triplet–triplet annihilation (TTA) materials, basically harness triplet excitons from the ...lowest triplet excited state (T1) to realize high efficiency. Here, a fluorescent material that can convert triplet excitons into singlet excitons from the high‐lying excited state (T2), referred to here as a “hot exciton” path, is reported. The energy levels of this compound are determined from the sensitization and nanosecond transient absorption spectroscopy measurements, i.e., small splitting energy between S1 and T2 and rather large T2–T1 energy gap, which are expected to impede the internal conversion (IC) from T2 to T1 and facilitate the reverse intersystem crossing from the high‐lying triplet state (hRISC). Through sensitizing the T2 state with ketones, the existence of the hRISC process with an ns‐scale delayed lifetime is confirmed. Benefiting from this fast triplet–singlet conversion, the nondoped device based on this “hot exciton” material reaches a maximum external quantum efficiency exceeding 10%, with a small efficiency roll‐off and CIE coordinates of (0.15, 0.13). These results reveal that the “hot exciton” path is a promising way to exploit high efficient, stable fluorescent emitters, especially for the pure‐blue and deep‐blue fluorescent organic light‐emitting devices.
A pure‐blue fluorescent organic light‐emitting device (OLED) based on phenanthroimidazole−anthracene derivative obtains a maximum external quantum efficiency of 10.5% with excellent stability. Experimental investigations reveal that the high efficiency is attributed to triplet exciton harvesting by reverse intersystem crossing from the high‐lying triplet state. The results demonstrates that “hot exciton” channels represent a promising way to construct high‐performance fluorescent OLEDs.
The electronic properties of correlated oxides are exceptionally sensitive to the orbital occupancy of electrons. Here we report an electron doping strategy via a chemical route, where interstitial ...dopants (for example, hydrogen) can be reversibly intercalated, realizing a sharp phase transition in a model correlated perovskite nickelate SmNiO3. The electron configuration of eg orbital of Ni(3+) t2g(6)eg(1) in SmNiO3 is modified by injecting and anchoring an extra electron, forming a strongly correlated Ni(2+) t2g(6)eg(2) structure leading to the emergence of a new insulating phase. A reversible resistivity modulation greater than eight orders of magnitude is demonstrated at room temperature. A solid-state room temperature non-volatile proton-gated phase-change transistor is demonstrated based on this principle, which may inform new materials design for correlated oxide devices. Electron doping-driven phase transition accompanied by large conductance changes and band gap modulation opens up new directions to explore emerging electronic and photonic devices with correlated oxide systems.
Epithelial-mesenchymal transition (EMT) is a highly conserved process in which polarized, immobile epithelial cells lose tight junctions, associated adherence, and become migratory mesenchymal cells. ...Several transcription factors, including the Snail/Slug family, Twist, δEF1/ZEB1, SIP1/ZEB2 and E12/E47 respond to microenvironmental stimuli and function as molecular switches for the EMT program. Snail is a zinc-finger transcriptional repressor controlling EMT during embryogenesis and tumor progression. Through its N-terminal SNAG domain, Snail interacts with several corepressors and epigenetic remodeling complexes to repress specific target genes, such as the E-cadherin gene (CDH1). An integrated and complex signaling network, including the RTKs, TGF-β, Notch, Wnt, TNF-α, and BMPs pathways, activates Snail, thereby inducing EMT. Snail expression correlates with the tumor grade, nodal metastasis of many types of tumor and predicts a poor outcome in patients with metastatic cancer. Emerging evidences indicate that Snail causes a metabolic reprogramming, bestows tumor cells with cancer stem cell-like traits, and additionally, promotes drug resistance, tumor recurrence and metastasis. Despite many new and exciting developments, several challenges remain to be addressed in order to understand more thoroughly the role of Snail in metastasis. Additional investigations are required to disclose the contribution of microenvironmental factors on tumor progression. This information will lead to a comprehensive understanding of Snail in cancer and will provide us with novel approaches for preventing and treating metastatic cancers.
Cisplatin-based adjuvant chemotherapy is the standard of care for patients with resected stage II–IIIA non-small-cell lung cancer (NSCLC). RADIANT and SELECT trial data suggest patients with ...EGFR-mutant stage IB–IIIA resected NSCLC could benefit from adjuvant EGFR tyrosine kinase inhibitor treatment. We aimed to compare the efficacy of adjuvant gefitinib versus vinorelbine plus cisplatin in patients with completely resected EGFR-mutant stage II–IIIA (N1–N2) NSCLC.
We did a randomised, open-label, phase 3 trial at 27 centres in China. We enrolled patients aged 18–75 years with completely resected (R0), stage II–IIIA (N1–N2), EGFR-mutant (exon 19 deletion or exon 21 Leu858Arg) NSCLC. Patients were stratified by N stage and EGFR mutation status and randomised (1:1) by Pocock and Simon minimisation with a random element to either gefitinib (250 mg once daily) for 24 months or intravenous vinorelbine (25 mg/m2 on days 1 and 8) plus intravenous cisplatin (75 mg/m2 on day 1) every 3 weeks for four cycles. The primary endpoint was disease-free survival in the intention-to-treat population, which comprised all randomised patients; the safety population included all randomised patients who received at least one dose of study medication. Enrolment to the study is closed but survival follow-up is ongoing. The study is registered with ClinicalTrials.gov, number NCT01405079.
Between Sept 19, 2011, and April 24, 2014, 483 patients were screened and 222 patients were randomised, 111 to gefitinib and 111 to vinorelbine plus cisplatin. Median follow-up was 36·5 months (IQR 23·8–44·8). Median disease-free survival was significantly longer with gefitinib (28·7 months 95% CI 24·9–32·5) than with vinorelbine plus cisplatin (18·0 months 13·6–22·3; hazard ratio HR 0·60, 95% CI 0·42–0·87; p=0·0054). In the safety population, the most commonly reported grade 3 or worse adverse events in the gefitinib group (n=106) were raised alanine aminotransferase and asparate aminotransferase (two 2% patients with each event vs none with vinorelbine plus cisplatin). In the vinorelbine plus cisplatin group (n=87), the most frequently reported grade 3 or worse adverse events were neutropenia (30 34% patients vs none with gefitinib), leucopenia (14 16% vs none), and vomiting (eight 9% vs none). Serious adverse events were reported for seven (7%) patients who received gefitinib and 20 (23%) patients who received vinorelbine plus cisplatin. No interstitial lung disease was noted with gefitinib. No deaths were treatment related.
Adjuvant gefitinib led to significantly longer disease-free survival compared with that for vinorelbine plus cisplatin in patients with completely resected stage II–IIIA (N1–N2) EGFR-mutant NSCLC. Based on the superior disease-free survival, reduced toxicity, and improved quality of life, adjuvant gefitinib could be a potential treatment option compared with adjuvant chemotherapy in these patients. However, the duration of benefit with gefitinib after 24 months might be limited and overall survival data are not yet mature.
Guangdong Provincial Key Laboratory of Lung Cancer Translational Medicine; National Health and Family Planning Commission of People's Republic of China; Guangzhou Science and Technology Bureau; AstraZeneca China.
Highly efficient organic thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) emitters for organic light‐emitting diodes (OLEDs) generally consist of a twisted ...donor–acceptor skeleton with aromatic amine donors. Herein, through introducing sulfur atoms into isomeric pentaphene and pentacene frameworks, we demonstrate a set of polycyclic luminophores exhibiting efficient TADF and RTP characters. The incorporation of sulfur atoms confirms a folded molecular plane, while intensifies singlet–triplet spin‐orbit coupling. Further, the isomeric effect has a significant effect on the electronic structure of excited state, giving rise to the investigated compounds tunable luminescence mechanisms of TADF and RTP. With efficient triplet harvesting ability, maximum external quantum efficiencies up to 25.1 % and 8.7 % are achieved for the corresponding TADF and RTP OLEDs, verifying the great potential of sulfur‐bridged frameworks for highly efficient devices.
By incorporating powerful electron‐donating sulfur atoms into isomeric pentaphene and pentacene frameworks, three highly efficient polycyclic thermally activated delayed fluorescence (TADF), room‐temperature phosphorescence (RTP), and mixed TADF/RTP molecules were developed for application in organic light‐emitting diodes.
•Solution treated aluminum alloy sheet was used in hot stamping.•Effects of heating temperature on formability and strengthening were investigated.•Effect of precipitate distribution on strengthening ...was analyzed.•Enhanced formability and strength can be obtained at 200 and 500°C simultaneously.
Aluminum alloy hot stamping has been developed to improve formability and avoid thermal distortion by combining hot forming and quenching in one operation in recent years. In order to investigate the effects of heating temperature on formability and strengthening of a solution treated Al–Mg–Si alloy sheet, uniaxial tensile test, deep drawing test and free bulging test were carried out at temperatures ranging from 25 to 500°C. The corresponding strengthening behavior was reflected by Vickers hardness measurement and microstructure was observed to clarify the strengthening mechanism with electron backscattering diffraction and scanning electron microscope methods. It was found that the fracture strain and limiting bulging height increased significantly until the temperature was elevated to 400°C. The limiting drawing ratio increased as temperature rose to 200°C and decreased afterwards. The hardness changed with temperature increasing, two peak hardness appeared at 200 and 500°C. The maximum hardness could arrive at 115HV. Formation of coarse β′ precipitates resulted in the decrease in hardness at temperatures ranging from 250 to 450°C. Enhanced formability and strength were obtained simultaneously at 200 and 500°C, either of which can be chosen as appropriate forming temperatures for hot stamping.
: This study focused on the effect of melatonin on in vitro maturation of porcine oocytes and their parthenogenetic embryonic development. Melatonin was measured in porcine follicular fluid of ...follicles of different sizes in the same ovary. Melatonin exists in follicular fluid, and the concentration is approximately 10−11 m. Its concentration decreased as the diameter of follicle increased, which suggests an effect of melatonin on oocyte maturation. Therefore, immature oocytes were cultured in vitro in maturation medium supplemented with melatonin (10−11, 10−9, 10−7, 10−5 and 10−3 m) or without melatonin. The oocytes at maturation stage were collected and activated. The parthenogenetic embryos were cultured and observed in medium supplemented with or without melatonin. Fresh immature oocytes without melatonin treatment were used as control. When only maturation medium was supplemented with 10−9 m melatonin, the cleavage rate, blastocyst rate and the cell number of blastocyst (70 ± 4.5%, 28 ± 2.4% and 50 ± 6.5%) were significantly higher (P < 0.05) than that of controls; when only culture medium was supplemented with melatonin, the highest cleavage rate, blastocyst rate and the cell number of blastocyst was observed at 10−7 m melatonin, which were significantly higher than that of controls (P < 0.05). The best results (cleavage rates 79 ± 8.4%, blastocyst rates 35 ± 6.7%) were obtained when both the maturation and culture medium were supplemented with 10−9 m melatonin respectively (P < 0.05). In conclusion, exogenous melatonin at the proper concentration may improve the in vitro maturation of porcine oocytes and their parthenogenetic embryonic development. Further research is needed to identify the effect of melatonin on in vitro and in vivo oocyte maturation and embryo development in porcine.
Image retargeting aims to adapt images to displays of small sizes and different aspect ratios. Effective retargeting requires emphasizing the important content while retaining surrounding context ...with minimal visual distortion. In this paper, we present such an effective image retargeting method using saliency-based mesh parametrization. Our method first constructs a mesh image representation that is consistent with the underlying image structures. Such a mesh representation enables easy preservation of image structures during retargeting since it captures underlying image structures. Based on this mesh representation, we formulate the problem of retargeting an image to a desired size as a constrained image mesh parametrization problem that aims at finding a homomorphous target mesh with desired size. Specifically, to emphasize salient objects and minimize visual distortion, we associate image saliency into the image mesh and regard image structure as constraints for mesh parametrization. Through a stretch-based mesh parametrization process we obtain the homomorphous target mesh, which is then used to render the target image by texture mapping. The effectiveness of our algorithm is demonstrated by experiments.
Numerous studies suggested that PM2.5 exposure was associated with increased risk of Alzheimer's disease (AD). But the precise mechanisms by which PM2.5 contributed to AD pathogenesis have not been ...clarified.
In the presence or absence of neurons, oligomeric amyloid beta (oAβ)-primed microglia were stimulated with PM2.5. Firstly, we determined the effects of PM2.5 exposure on neuronal injury and inflammation in neurons-microglia co-cultures. Then, we examined whether NLRP3 inflammasome activation was involved in PM2.5-induced inflammation. After that, we investigated whether PM2.5 exposure increased ROS level in oAβ-stimulated microglia. At last, we examined whether ROS and NLRP3 inflammasome activation was required for PM2.5-induced neuronal injury in neurons-microglia co-cultures.
In the present study, we showed that PM2.5 exposure aggravated oAβ-induced neuronal injury and inflammation in neurons-microglia co-cultures via increasing IL-1β production. Further, PM2.5-induced IL-1β production in oAβ-stimulated microglia was possibly dependent on NLRP3 inflammasome activation. Meanwhile, PM2.5 exposure increased ROS level in oAβ-stimulated microglia. ROS was required for PM2.5-induced IL-1β production and NLRP3 inflammasome activation in oAβ-stimulated microglia. More importantly, ROS and NLRP3 inflammasome activation was required for PM2.5-induced neuronal injury in neurons-microglia co-cultures.
For the first time, these results suggested that the effects of PM2.5 under AD context were possibly mediated by NLRP3 inflammasome activation, which was triggered by ROS. Taken together, these findings have deepened our understanding on the role of PM2.5 in AD pathogenesis.
Metal oxides derived from layered double hydroxides (LDHs) are expected to obtain low-temperature denitrification (de-NOx) catalysts with high catalytic activity and H2O/SO2 tolerance in the ...selective catalytic reduction (SCR) of NOx with NH3. In current work, we successfully prepared Gd-modified Mn-Co metal oxides derived from Gd-modified Mn-Co LDHs. The resultant Gd-modified Mn-Co metal oxides exhibit excellent catalytic activity and high H2O/SO2 tolerance in the NH3-SCR de-NOx reaction. The reasons for the enhancement can be ascribed to the unique surface physicochemical properties inherited from LDHs and the modification of Gd, which increase the specific surface area, improve the relative content of Mn4+ and Co3+ on the surface, enhance the number of acidic sites, strengthen the reducibility of catalyst, resulting in the enhanced catalytic activity and H2O/SO2 tolerance. Additionally, it is demonstrated that the NH3-SCR de-NOx reaction occurred on the surface of Gd-modified Mn-Co oxides followed both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. This study provides us with a design approach to promote catalytic activity and H2O/SO2 tolerance through morphology control and rare earth modification.
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