18 research outputs found

    The Quadratic Shortest Path Problem and its Genetic Algorithm

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    The quadratic shortest path (QSP) problem is to find a path from a node to another node in a given network such that the total cost includes two kinds of costs, say direct cost and interactive cost, is minimum. The direct cost is the cost associated with each arc and the interactive cost occurs when two arcs appear simultaneously in the shortest path. In this paper, the concept of the quadratic shortest path is initialized firstly. Then a spanning tree-based genetic algorithm is designed for solving the quadratic shortest path problem. Finally, a numerical example is given

    Modeling Multi-wavelength Pulse Profiles of Millisecond Pulsar PSR B1821-24

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    PSR B1821-24 is a solitary millisecond pulsar (MSP) which radiates multi-wavelength pulsed photons. It has complex radio, X-ray and γ\gamma-ray pulse profiles with distinct peak phase-separations that challenge the traditional caustic emission models. Using the single-pole annular gap model with suitable magnetic inclination angle (α=40\alpha=40^\circ) and viewing angle (ζ=75\zeta=75^\circ), we managed to reproduce its pulse profiles of three wavebands. It is found that the middle radio peak is originated from the core gap region at high altitudes, and the other two radio peaks are originated from the annular gap region at relatively low altitudes. Two peaks of both X-ray and γ\gamma-ray wavebands are fundamentally originated from annular gap region, while the γ\gamma-ray emission generated from the core gap region contributes somewhat to the first γ\gamma-ray peak. Precisely reproducing the multi-wavelength pulse profiles of PSR B1821-24 enables us to understand emission regions of distinct wavebands and justify pulsar emission models.Comment: Accepted for publication in Ap

    Interfacial Manganese-Doping in CsPbBr3 Nanoplatelets by Employing a Molecular Shuttle

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    Mn-doping in cesium lead halide perovskite nanoplatelets (NPls) is of particular importance where strong quantum confinement plays a significant role towards the exciton-dopant coupling. In this work, we report an immiscible bi-phasic strategy for post-synthetic Mn-doping of CsPbX3 (X=Br, Cl) NPls. A systematic study shows that electron-donating oleylamine acts as a shuttle ligand to transport MnX2 through the water-hexane interface and deliver it to the NPls. The halide anion also plays an essential role in maintaining an appropriate radius of Mn2+ and thus fulfilling the octahedral factor required for the formation of perovskite crystals. By varying the thickness of parent NPls, we can tune the dopant incorporation and, consequently, the exciton-to-dopant energy transfer process in doped NPls. Time-resolved optical measurements offer a detailed insight into the exciton-to-dopant energy transfer process. This new approach for post-synthetic cation doping paves a way towards exploring the cation exchange process in several other halide perovskites at the polar-nonpolar interface

    A multi-layer device for light-triggered hydrogen production from alkaline methanol

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    It usually requires high temperature and high pressure to reform methanol with water to hydrogen with high turnover frequency (TOF). Here we show that hydrogen can be produced from alkaline methanol on a light‐triggered multi‐layer system with a very high hydrogen evolution rate up to ca. 1 μmol s(−1) under the illumination of a standard Pt‐decorated carbon nitride. The system can achieve a remarkable TOF up to 1.8×10(6) moles of hydrogen per mole of Pt per hour under mild conditions. The total turnover number (TTN) of 470 000 measured over 38 hours is among the highest reported. The system does not lead to any CO(x) emissions, hence it could feed clean hydrogen to fuel cells. In contrast to a slurry system, the proposed multi‐layer system avoids particle aggregation and effectively uses light and Pt active sites. The performance is also attributed to the light‐triggered reforming of alkaline methanol. This notable performance is a promising step toward practical light‐driven hydrogen generation

    Data_Sheet_1_A Dynamic Analysis of the Asymmetric Effects of the Vocational Education and Training on Economic Growth, Evidence From China.pdf

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    Since 2010, China's economic growth has stagnated due to an unbalanced regional industrial structure and lack of sufficient qualified technical personnel. A nonlinear autoregressive distributed lag (NARDL) model has been used in this study to examine the asymmetric effects of secondary vocational education and training (SVET) and higher vocational education and training (HVET) and their interaction with high-tech industries on economic growth over the period 1980–2020. The findings show that an increase in secondary vocational education and training (SVET) significantly boosts long-term economic growth, while a decrease in secondary vocational education and training (SVET) insignificantly reduces long-term China economic growth. Likewise, the upward change in higher vocational education and training (HVET) promotes and the downward fluctuation in higher vocational education and training (HVET) significantly reduces China's long-term economic growth. The moderating role of secondary vocational education in the impact of high-tech industries on China's economic growth is positive, but not significant. However, higher vocational education plays a significant positive moderating role in high technology industries impact on economic growth. Strategically, the study analysis suggests that economic transition prosperity can be achieved by encouraging higher vocational education and the equal development of high-tech industries in all regions. In addition, this study also proposes to cultivate high-quality talents related to high-tech development and modern industrial innovation and upgrading through higher vocational education, improve productivity, and promote the country's intensive development.</p

    Liquiritin exhibits anti-acute lung injury activities through suppressing the JNK/Nur77/c-Jun pathway

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    Abstract Background Licorice (Glycyrrhiza uralensis Fisch.), a well-known traditional medicine, is traditionally used for the treatment of respiratory disorders, such as cough, sore throat, asthma and bronchitis. We aim to investigate the effects of liquiritin (LQ), the main bioactive compound in licorice against acute lung injury (ALI) and explore the potential mechanism. Methods Lipopolysaccharide (LPS) was used to induce inflammation in RAW264.7 cells and zebrafish. Intratracheal instillation of 3 mg/kg of LPS was used for induction an ALI mice model. The concentrations of IL-6 and TNF-α were tested using the enzyme linked immunosorbent assay. Western blot analysis was used to detect the expression of JNK/Nur77/c-Jun related proteins. Protein levels in bronchoalveolar lavage fluid (BALF) was measured by BCA protein assay. The effect of JNK on Nur77 transcriptional activity was determined by luciferase reporter assay, while electrophoretic mobility shift assay was used to examine the c-Jun DNA binding activity. Results LQ has significant anti-inflammatory effects in zebrafish and RAW264.7 cells. LQ inhibited the expression levels of p-JNK (Thr183/Tyr185), p-Nur77 (Ser351) and p-c-Jun (Ser63), while elevated the Nur77 expression level. Inhibition of JNK by a specific inhibitor or small interfering RNA enhanced the regulatory effect of LQ on Nur77/c-Jun, while JNK agonist abrogated LQ-mediated effects. Moreover, Nur77-luciferase reporter activity was suppressed after JNK overexpression. The effects of LQ on the expression level of c-Jun and the binding activity of c-Jun with DNA were attenuated after Nur77 siRNA treatment. LQ significantly ameliorated LPS-induced ALI with the reduction of lung water content and BALF protein content, the downregulation of TNF-α and IL-6 levels in lung BALF and the suppression of JNK/Nur77/c-Jun signaling, which can be reversed by a specific JNK agonist. Conclusion Our results indicated that LQ exerts significant protective effects against LPS-induced inflammation both in vivo and in vitro via suppressing the activation of JNK, and consequently inhibiting the Nur77/c-Jun signaling pathway. Our study suggests that LQ may be a potential therapeutic candidate for ALI and inflammatory disorders

    Immune landscape and subtypes in primary resectable oral squamous cell carcinoma: prognostic significance and predictive of therapeutic response

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    Background Immune landscape of cancer has been increasingly recognized as a key feature affecting disease progression, prognosis and therapeutic response. Here, we sought to comprehensively characterize the patterns of tumor-infiltrating immune cells (TIIs) in primary oral squamous cell carcinoma (OSCC) and develop immune features-derived models for prognostication and therapeutic prediction.Methods A total number of 392 patients with OSCC receiving ablative surgery at three independent centers were retrospectively enrolled and defined as training, testing and validation cohorts. Detailed features of 12 types of TIIs at center of tumor and invasive margin were assessed by immunohistochemistry coupled with digital quantification. TIIs abundance in OSCC was also estimated by bioinformatics approaches using multiple publicly available data sets. Prognostic models based on selected immune features were trained via machine learning approach, validated in independent cohorts and evaluated by time-dependent area under the curves and concordance index (C-index). Immune types of OSCC were further identified by consensus clustering and their associations with genetic, molecular features and patient survival were clarified.Results Patterns of TIIs infiltration varied among patients and dynamically evolved along with tumor progression. Prognostic models based on selected TIIs were identified as efficient and sensitive biomarkers to stratify patients into subgroups with favorable or inferior survival as well as responders or non-responders to postoperative radiotherapy or immunotherapy. These models outperformed multiple conventional biomarkers and immune-related scores in prognostic prediction. Furthermore, we identified two main immune subtypes of OSCC (immune-hot and immune-cold) which harbored characteristic TIIs infiltrations and genomic and molecular features, and associated with patient survival.Conclusions Our results delineated immune landscape and subtypes in OSCC, consolidated their clinical values as robust biomarkers to predict patient survival and therapeutic benefits and reinforced key roles of TIIs and tumor-immune interactions underlying oral tumorigenesis, ultimately facilitating development of tailed immunotherapeutic strategies

    Highly Luminescent and Stable Perovskite Nanocrystals with Octylphosphonic Acid as a Ligand for Efficient Light-Emitting Diodes

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    All inorganic perovskite nanocrystals (NCs) of CsPbX<sub>3</sub> (X = Cl, Br, I, or their mixture) are regarded as promising candidates for high-performance light-emitting diode (LED) owing to their high photoluminescence (PL) quantum yield (QY) and easy synthetic process. However, CsPbX<sub>3</sub> NCs synthesized by the existing methods, where oleic acid (OA) and oleylamine (OLA) are generally used as surface-chelating ligands, suffer from poor stability due to the ligand loss, which drastically deteriorates their PL QY, as well as dispersibility in solvents. Herein, the OA/OLA ligands are replaced with octylphosphonic acid (OPA), which dramatically enhances the CsPbX<sub>3</sub> stability. Owing to a strong interaction between OPA and lead atoms, the OPA-capped CsPbX<sub>3</sub> (OPA-CsPbX<sub>3</sub>) NCs not only preserve their high PL QY (>90%) but also achieve a high-quality dispersion in solvents after multiple purification processes. Moreover, the organic residue in purified OPA-CsPbBr<sub>3</sub> is only ∼4.6%, which is much lower than ∼29.7% in OA/OLA-CsPbBr<sub>3</sub>. Thereby, a uniform and compact OPA-CsPbBr<sub>3</sub> film is obtained for LED application. A green LED with a current efficiency of 18.13 cd A<sup>–1</sup>, corresponding to an external quantum efficiency of 6.5%, is obtained. Our research provides a path to prepare high-quality perovskite NCs for high-performance optoelectronic devices

    Interfacial Synthesis of Highly Stable CsPbX<sub>3</sub>/Oxide Janus Nanoparticles

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    The poor stability of CsPbX<sub>3</sub> (X = Cl, Br, I) nanocrystals (NCs) has severely impeded their practical applications. Although there are some successful examples on encapsulating multiple CsPbX<sub>3</sub> NCs into an oxide or polymer matrix, it has remained a serious challenge for the surface modification/encapsulation using oxides or polymers at a single particle level. In this work, monodisperse CsPbX<sub>3</sub>/SiO<sub>2</sub> and CsPbBr<sub>3</sub>/Ta<sub>2</sub>O<sub>5</sub> Janus nanoparticles were successfully prepared by combining a water-triggered transformation process and a sol–gel method. The CsPbBr<sub>3</sub>/SiO<sub>2</sub> NCs exhibited a photoluminescence quantum yield of 80% and a lifetime of 19.8 ns. The product showed dramatically improved stability against destruction by air, water, and light irradiation. Upon continuous irradiation by intense UV light for 10 h, a film of the CsPbBr<sub>3</sub>/SiO<sub>2</sub> Janus NCs showed only a slight drop (2%) in the PL intensity, while a control sample of unmodified CsPbBr<sub>3</sub> NCs displayed a 35% drop. We further highlighted the advantageous features of the CsPbBr<sub>3</sub>/SiO<sub>2</sub> NCs in practical applications by using them as the green light source for the fabrication of a prototype white light emitting diode, and demonstrated a wide color gamut covering up to 138% of the National Television System Committee standard. This work not only provides a novel approach for the surface modification of individual CsPbX<sub>3</sub> NCs but also helps to address the challenging stability issue; therefore, it has an important implication toward their practical applications
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