Pt/CeO2 catalysts with different support shapes and prereduction temperatures were prepared and tested in the liquid-phase hydrogenation of nitrobenzene. Detailed characterizations reveal that the ...support shape effect of Pt/CeO2 catalysts on nitrobenzene hydrogenation originates from the exposed crystal planes on CeO2 with different reducibilities. A high-energy surface is readily reduced to generate more Ce3+ surface sites and oxygen vacancies, not only favoring the dispersion and stabilization of Pt species due to stronger metal–support interaction but also providing more adsorption sites for reactants and intermediates. Reduction treatment at high temperatures has been proved to be an effective way to improve the performance of Pt/CeO2 catalysts by providing additional Ce3+ surface sites and high H-spillover capability. The additional Ce3+ far away from Pt, derived from a high-temperature reduction, can adsorb the N-phenylhydroxylamine intermediate more effectively due to its stronger electron-donating ability and in turn promote aniline formation. It is also found that Na ions with suitable content facilitate the generation and stabilization of surface Ce3+ by charge transfer and help Pt particles to maintain a smaller size. Consequently, a 0.25 wt % Pt catalyst, supported on Na-containing CeO2 nanorods and reduced at 600 °C, displays a high level of aniline productivity of 40.8 molAN/gPt/h and excellent stability in nitrobenzene hydrogenation at room temperature. A pathway of nitrobenzene hydrogenation catalyzed by Pt/CeO2 is also proposed.
Hypoxia, a salient feature of most solid tumors, confers invasiveness and resistance to the tumor cells. Oxygen-consumption photodynamic therapy (PDT) suffers from the undesirable impediment of local ...hypoxia in tumors. Moreover, PDT could further worsen hypoxia. Therefore, developing effective strategies for manipulating hypoxia and improving the effectiveness of PDT has been a focus on antitumor treatment. In this review, the mechanism and relationship of tumor hypoxia and PDT are discussed. Moreover, we highlight recent trends in the field of nanomedicines to modulate hypoxia for enhancing PDT, such as oxygen supply systems, down-regulation of oxygen consumption and hypoxia utilization. Finally, the opportunities and challenges are put forward to facilitate the development and clinical transformation of PDT.
Review of mechanisms and relationships of tumor hypoxia and photodynamic therapy as well as four nanomedicine delivery systems for manipulating tumor hypoxia to enhance the photodynamic therapy. Display omitted
The quantum anomalous Hall (QAH) effect, which has been realized in magnetic topological insulators (TIs), is the key to applications of dissipationless quantum Hall edge states in electronic ...devices. However, investigations and utilizations of the QAH effect are limited by the ultralow temperatures needed to reach full quantization—usually below 100 mK in either Cr‐ or V‐doped (Bi,Sb)2Te3 of the two experimentally confirmed QAH materials. Here it is shown that by codoping Cr and V magnetic elements in (Bi,Sb)2Te3 TI, the temperature of the QAH effect can be significantly increased such that full quantization is achieved at 300 mK, and zero‐field Hall resistance of 0.97 h/e2 is observed at 1.5 K. A systematic transport study of the codoped (Bi,Sb)2Te3 films with varied Cr/V ratios reveals that magnetic codoping improves the homogeneity of ferromagnetism and modulates the surface band structure. This work demonstrates magnetic codoping to be an effective strategy for achieving high‐temperature QAH effect in TIs.
In Cr and V codoped (Bi,Sb)2Te3 topological insulator films, the quantum anomalous Hall (QAH) effect is achieved at 300 mK, about one order of magnitude higher than that for singly Cr‐ or V‐doped ones, and the energy scale of QAH state reaches 1.4 K. The transport study of the codoped films with varied Cr/V ratios reveals the origins of enhancement.
We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall ...conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.
Abstract
Background
We recently reported histone methyltransferase enhancer of zeste homolog 2 (EZH2) as a key epigenetic regulator that contributes to the dysfunction of innate immune responses to ...sepsis and subsequent lung injury by mediating the imbalance of macrophage polarization. However, the role of EZH2 in acute respiratory distress syndrome (ARDS)-associated fibrosis remains poorly understood.
Methods
In this study, we investigated the role and mechanisms of EZH2 in pulmonary fibrosis in a murine model of LPS-induced ARDS and in ex-vivo cultured alveolar macrophages (MH-S) and mouse lung epithelial cell line (MLE-12) by using 3-deazaneplanocin A (3-DZNeP) and EZH2 the small interfering (si) RNA.
Results
We found that treatment with 3-DZNeP significantly ameliorated the LPS-induced direct lung injury and fibroproliferation by blocking EMT through TGF-β1/Smad signaling pathway and regulating shift of macrophage phenotypes. In the ex-vivo polarized alveolar macrophages cells, treatment with EZH2 siRNA or 3-DZNeP suppressed the M1 while promoted the M2 macrophage differentiation through modulating the STAT/SOCS signaling pathway and activating PPAR-γ. Moreover, we identified that blockade of EZH2 with 3-DZNeP suppressed the epithelial to mesenchymal transition (EMT) in co-cultured bronchoalveolar lavage fluid (BALF) and mouse lung epithelial cell line through down-regulation of TGF-β1, TGF-βR1, Smad2 while up-regulation of Smad7 expression.
Conclusions
These results indicate that EZH2 is involved in the pathological process of ARDS-associated pulmonary fibrosis. Targeting EZH2 may be a potential therapeutic strategy to prevent and treat pulmonary fibrosis post ARDS.
A general visible light-induced sulfonylation/cyclization to produce quinoline-2,4-diones was achieved under photocatalyst-free conditions. The reactions were performed at room temperature, and ...various substituents (halogen, alkyl, aryl) and substituted products were obtained with 29 examples within 2 h. Large-scale synthesis and derivatization study via carbonyl reduction to produce easily modified hydroxyl groups and convenient
-Ts deprotection showed the potential utility of this strategy.
To improve the roadway adaptability and control accuracy of anchoring equipment, a stepping anchoring device was designed. A permanent-magnet synchronous motor control and a harmonic suppression ...algorithm were integrated to optimize the dynamic control system of stepping-type anchoring equipment. The results of an experimental simulation and analysis showed that when the coefficient of coal rock hardness f = 5, 6, and 7, the pulsation coefficient of the hydraulic pump outlet pressure, hydraulic motor output speed, and pump-controlled hydraulic cylinder advance speed in the hydraulic circuit of a pump-controlled motor did not exceed 3% after the equipment based on sliding mode control (SMC) entered the steady state, while the maximum pulsation coefficient was only 32.5% of the PI control. Based on the SMC, the harmonic components of the permanent magnet synchronous motor in the power system were suppressed and compensated for. This enhanced the stiffness of the hydraulic system under motor drive. When the rock stiffness factor gradually changed from f = 5 to f = 8 and increased suddenly from f = 5 to f = 6, the pressure overshoot at the outlet of the hydraulic pump of the pump-controlled motor system was reduced from 11.19% to 7.97% and from 61.19% to 52.88%, respectively, compared with that before the optimization. It was thereby proven that SMC based on harmonic suppression can effectively reduce the system pulsation caused by the multi-factor coupling of anchoring equipment and provide technical support for the optimal control of the power system of stepping-type anchoring equipment.
Triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) present excellent performances in harvesting multivariant mechanical energy. However, the conductivity of electrode has ...become one of the important factors restricting the mechanical energy acquisition under the large deformation and multiple freedom degrees. In this work, a highly conductive stretchable electrode based piezoelectric-enhanced triboelectric nanogenerator (P-TENG) with outstanding performance is reported. Ultra-flexible silicone rubber based triboelectric part with surface modification and piezoelectric part with BaTiO3 dispersed possess excellent electrical and mechanical property, at the same time, the stretchable electrode based on liquid metal could maintain low resistance even under large deformation. The peak to peak open-circuit voltage (VOC) and short-circuit current (ISC) of P-TENG could reach 1.38 kV and 36.13 μA, respectively. The instantaneous power density can reach 1.1 mW/cm2 and the charge quantity in single capacitor charging circle is approximately 0.30 μC. It also has the surpassing force-electrical linearity that the output voltage positively correlating to stretching speeds and stretching rates. The resistance increments of electrode below 0.32 Ω under stretching rate more than 200% and the percentage of breaking elongation could reach 645%. In applying experiments, the P-TENG could directly light 16 LEDs and effectively identify the motion signals. This work provides a new thought for nanogenerator (NG) with high stretchability and applied to collect irregular mechanical energy.
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•The resistance of electrode prepared by liquid metal is less than 2.0 Ω even under a tensile rate of 200%.•The output power density of piezoelectric-enhanced triboelectric nanogenerator could reach 1.1 mW/cm2.•The broken elongation of piezoelectric-enhanced triboelectric nanogenerator could reach 645%.•The nanogenerator could be used for mechanical energy collection and motional signals recognition.
Abstract
To evaluate the efficiency of a 20 μg hepatitis B vaccine(HepB) for disease prevention in two counties in Henan Province, China. A questionnaire was designed to examine the information of ...hepatitis B surface antigen (HBsAg) positive pregnant women, and their blood samples were collected to test for hepatitis B e antigen (HBeAg), hepatitis B e antibody, and hepatitis B virus (HBV) DNA. Three doses of 20 μg HepB and one dose of hepatitis B immune globulin(HBIG) were administered to newborns. Blood samples were collected from children one month after their complete immunization to test for HBsAg and hepatitis B surface antibody(HBsAb). A total of 419 HBsAg positive-pregnant women and 430 newborns were investigated. The average age of pregnant women was 29.6 ± 4.3 years, with an HBeAg positive rate of 29.1% (122/419). All newborns received their first dose of 20 μg hepatitis B vaccine and 100 IU HBIG within 12 h after birth. Six infants (1.9%, 6/319) tested positive for HBsAg and negative for HBsAb after one month of receiving the three basic doses of HepB. The geometric mean concentration(GMC) of HBsAb-positive infants was 861.6 mIU/mL, and their HBsAb antibody titers decreased with age. Immunization of children born to HBsAg-positive mothers with 20 μg HepB got the satisfactory effect on preventing mother-to-child transmission.
As the intensity of work increases, many of us sit for long hours while working in the office. It is not easy to sit properly at work all the time and sitting for a long time with wrong postures may ...cause a series of health problems as time goes by. In addition, monitoring the sitting posture of patients with spinal disease would be beneficial for their recovery. Accordingly, this paper designs and implements a sitting posture recognition system from a flexible array pressure sensor, which is used to acquire pressure distribution map of sitting hips in a real-time manner. Moreover, an improved self-organizing map-based classification algorithm for six kinds of sitting posture recognition is proposed to identify whether the current sitting posture is appropriate. The extensive experimental results verify that the performance of ISOM-based sitting posture recognition algorithm (ISOM-SPR) in short outperforms that of four kinds of traditional algorithms including decision tree-based (DT), K-means-based (KM), back propagation neural network-based (BP), self-organizing map-based (SOM) sitting posture recognition algorithms. Finally, it is proven that the proposed system based on ISOM-SPR algorithm has good robustness and high accuracy.
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