Solar‐driven overall water splitting is an ideal way to generate renewable energy while still challenging. For the first time, this work combined covalent organic frameworks (COFs) and piezoelectric ...material by covalent linkages to form Z‐scheme core@shell heterostructure for overall water splitting. Benefiting from the synergistic effect between the polarized electric field and photo‐generated charges, as well as the precise adjustment of shell thickness, the carrier separation and utilization efficiency is greatly improved. The optimal BiFeO3@TpPa‐1‐COF photocatalyst revealed hydrogen (H2) and oxygen (O2) production rates of 1416.4 and 708.2 μmol h−1 g−1 under the excitation of ultrasonication coupled with light irradiation, which is the best performance among various piezo‐ and COF‐based photocatalysts. This provides a new sight for the practical application of highly efficient photocatalytic overall water splitting.
We combined covalent organic frameworks (COFs) and piezoelectric material by covalent bonds to form a Z‐scheme core@shell heterostructure piezo‐photocatalyst with tunable shell thickness for overall water splitting. The optimal sample reveals the unprecedented H2 and O2 production rates of 1416.4 and 708.2 μmol h−1 g−1 under the excitation of ultrasonication coupled with visible light irradiation.
This paper observes the relationship between variables that cannot be explained through the structure of variable explanatory variance-covariance and explores the method of applying the theoretical ...model of principal component analysis and factor analysis by using the method of hypothesis. After studying the scope of application of the principal component analysis method and factor analysis method, both of which can be used in the general model of comprehensive evaluation of variables, the scientific management approach of planned behavior for student management in the classroom of college and university civic education is proposed. By empirically analyzing the Civics learning management and education evaluation of students and teachers in L colleges and universities, the experimental results show that the cumulative contribution rate of the three principal components, namely, high moral character, perfect personality and good communication, is 87.4% as the main observed variables. In the cluster analysis of the Civics performance, the best Civics performance was found in the category 2 and category 1 students in college L, with a total of 9 students conforming to it. The four principal component factors of the first-ranked teachers did not differ much, respectively 1.6485, 0.4653, 1.7463, −0.645, except for the teacher numbered 1, who had a big difference in the ranking place under the two evaluation methods, and the rest of the teachers did not have any difference, and on the whole, the quality of Civic and Political education in College L was better, and the harmonization with the student management was good.
The physicochemical properties and multiple bioactive effects of ginseng oligopeptides (GOPs), plant-derived small molecule bioactive peptides, suggest a positive influence on health span and ...longevity. Given this, cellular senescence is the initiating factor and key mechanism of aging in the organism, and thus the current study sought to explore the effects of GOPs on H
O
-induced cellular senescence and its potential mechanisms. Senescence was induced in mouse embryonic fibroblasts NIH/3T3 by 4 h of exposure to 200 µM H
O
and confirmed using CCK-8 assay and Western blot analyses of p16
and p21
after 24 h of growth medium administration with or without GOPs supplementation (25, 50, and 100 µg/mL). We found that GOPs delayed oxidative stress-induced NIH/3T3 senescence by inhibiting the G1 phase arrest, increasing DNA synthesis in the S phase, decreasing the relative protein expression of p16
and p21
, promoting cell viability, protecting DNA, and enhancing telomerase (TE) activity. Further investigation revealed that the increase in antioxidative capacity and anti-inflammation capacity might form the basis for the retarding of the senescence effects of GOPs. Furthermore, GOPs supplementation significantly improved mitochondrial function and mitochondrial biogenesis via the NAD
/SIRT1/PGC-1𝛼 pathway. These findings indicate that GOPs may have a positive effect on health span and lifespan extension via combating cellular senescence, oxidative stress, and inflammation, as well as modulating longevity regulating pathway NAD
/SIRT1/PGC-1𝛼.
Exosomes are 30–120 nm endocytic membrane-derived vesicles that participate in cell-to-cell communication and protein and RNA delivery. Exosomes harbor a variety of proteins, nucleic acids, and ...lipids and are present in many and perhaps all bodily fluids. A significant body of literature has demonstrated that molecular constituents of exosomes, especially exosomal proteins and microRNAs (miRNAs), hold great promise as novel biomarkers for clinical diagnosis. In this minireview, we summarize recent advances in the research of exosomal biomarkers and their potential application in clinical diagnostics. We also provide a brief overview of the formation, function, and isolation of exosomes.
Shivering associated with spinal anesthesia during Cesarean delivery is an uncomfortable experience for the parturient, which may also cause adverse effects. In this prospective, randomized, ...double-blind, placebo-controlled study, we sought to evaluate the effect of intrathecal dexmedetomidine, administered as an adjunct to hyperbaric bupivacaine for Cesarean delivery, on the incidence and severity of shivering associated with spinal anesthesia. Patients undergoing Cesarean delivery were randomly allocated to three groups of 30 patients each. Experimental treatments were added to hyperbaric bupivacaine as follows: Patients in group I (control) were administered isotonic saline. Patients in groups II and III received dexmedetomidine (2.5, 5 µg, respectively), mixed with isotonic saline. Shivering was observed in 11, 10 and 2 patients in groups I, II and III, respectively. The incidence of shivering in group III was significantly lower than that in groups I (p=0.005) and II (p=0.01). The severity of shivering was significantly different between the three groups (p=0.01). There were no significant inter-group differences with respect to mean arterial pressure and heart rate at any time point after administration of intrathecal local anesthesia (p>0.05). Intrathecal dexmedetomidine (5 µg) administered as an adjunct to hyperbaric bupivacaine during Cesarean delivery significantly reduced the incidence and intensity of shivering associated with spinal anesthesia.
► The Neoproterozoic magmatisms are determined in the Erguna Massif, NE China. ► The Neoproterozoic magmatisms can be subdivided into four stages: ∼851, ∼792, ∼762, and ∼737Ma. ► The Neoproterozoic ...magmatisms consist mainly of A-type granites and bimodal igneous rocks. ► The Neoproterozoic magmatisms reveal an extensional environment linked to the breakup of Rodinia.
In this paper, we discuss new zircon U–Pb ages, major and trace element analyses, and Hf isotope data for Neoproterozoic intrusive rocks in the Erguna Massif of NE China, in the eastern segment of the Central Asian Orogenic Belt (CAOB). Our aim is to elucidate the tectonic origin of the Erguna Massif and its relationship to the breakup of the Rodinia supercontinent. Zircons collected from a gabbro and five granitoids are euhedral–subhedral, and display striped absorption or fine-scale oscillatory growth zoning in CL images, implying a magmatic origin. Zircon U–Pb dating demonstrates that these rocks were emplaced in four stages during the Neoproterozoic, as follows: (1) ∼851Ma, an intrusive suite of syenogranites; (2) ∼792Ma, a bimodal igneous rock association of gabbros and gabbro–diorites, together with syenogranites; (3) ∼762Ma, a suite of granodiorites; and (4) ∼737Ma, another suite of syenogranites. These magmatic events are similar time-wise to those in the Tuva–Mongolia Massif and the northern Baikal region of the southern Siberian Craton, suggesting an affinity between the Erguna Massif and the southern margin of the Siberian Craton. The Neoproterozoic granitoids in the Erguna Massif have SiO2=68.72–78.36wt.%, Mg#=17–33, Al2O3=11.66–14.79wt.%, (Na2O+K2O)=7.46–9.27wt.%, and A/CNK=0.95–1.14; they are metaluminous to peraluminous, and similar to A-type granites. Moreover, these Neoproterozoic granitoids are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), and depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs, Nb, Ta, and Ti). Their zircon ɛHf (t) values mainly range from +2.7 to +8.1, which implies that their primary magmas were derived from partial melting of a depleted lower crust. In contrast, the Neoproterozoic gabbros and gabbro–diorites in the Erguna Massif have low SiO2 (50.43–51.53wt.%), relatively high Mg# (46–51), high Ni (22.5–23.8ppm), Cr (41.5–72.2ppm), and Co contents (28.9–32.5ppm), and are enriched in LILEs and LREEs but depleted in HREEs and HFSEs such as Nb and Ta. Their ɛHf (t) values range from +2.5 to +5.4. Together, these characteristics suggest the primary magmas of the gabbros and gabbro–diorites were derived by partial melting of a depleted mantle wedge that had been metasomatized by fluids derived from a subducted slab. In the context of the assembly and breakup of the Rodinia supercontinent, and Neoproterozoic magmatic events along the southern margin of the Siberian Craton, we conclude that the Neoproterozoic A-type granitoids, gabbros, and gabbro–diorites of the Erguna Massif formed in an extensional environment related to rifting, corresponding to the breakup of the Rodinia supercontinent.
Steviosides extracted from the leaves of the plant Stevia rebaudiana are increasingly used in the food industry as natural low-calorie sweeteners. Phthalates in food are often assumed to arise from ...food containers or packaging materials. Here, experiments were carried out to identify the potential sources of DMP, DBP, DIBP, and DEHP in the leaves of stevioside through investigation of their content in native stevioside tissues, soils, and associated agronomic materials. The results show that phthalate contamination was present in all the samples tested, and the influence of regional factors at the provincial level on the content of plasticizers in stevia leaves was not significant. Phthalates in stevia leaves can be absorbed into the plant body through leaves and roots. Using resin removal, the phthalate content in stevioside glycosides was reduced to less than 0.05 ppm, and some indicators were far lower than the limit standard in EU food.
Hydrological time series forecasting is one of the most important applications in modern hydrology, especially for effective reservoir management. In this research, the auto-regressive integrated ...moving average (ARIMA) model coupled with the ensemble empirical mode decomposition (EEMD) is presented for forecasting annual runoff time series. First, the original annual runoff time series is decomposed into a finite and often small number of intrinsic mode functions (IMFs) and one residual series using EEMD technique for a deep insight into the data characteristics. Then each IMF component and residue is forecasted, respectively, through an appropriate ARIMA model. Finally, the forecasted results of the modeled IMFs and residual series are summed to formulate an ensemble forecast for the original annual runoff series. Three annual runoff series from Biuliuhe reservoir, Dahuofang reservoir and Mopanshan reservoir, in China, are investigated using developed model based on the four standard statistical performance evaluation measures (RMSE, MAPE, R and NSEC). The results obtained in this work indicate that EEMD can effectively enhance forecasting accuracy and that the proposed EEMD-ARIMA model can significantly improve ARIMA time series approaches for annual runoff time series forecasting.
Considering the flexibility, adjustable pore structure, and abundant active sites of metal–organic frameworks (MOFs), rational design and fine control of the MOF-based hetero-nanocrystals is a highly ...important and challenging subject. In this work, self-assembly of a 3D hollow BiOBr@Bi-MOF microsphere was fabricated through precisely controlled dissociation kinetics of the self-sacrificial template (BiOBr) for the first time, where the residual quantity of BiOBr and the formation of Bi-MOF were carefully regulated by changing the reaction time and the capability of coordination. Meanwhile, the hollow microstructure was formed in BiOBr@Bi-MOF through the Oswald ripening mechanism to separate photogenerated electron–hole pairs and increase the adsorption capacity of Bi-MOF for dyes, which significantly enhanced the photocatalytic degradation efficiency of RhB from 56.4% for BiOBr to 99.4% for the optimal BiOBr@Bi-MOF microsphere. This research broadens the selectivity of semiconductor/MOF hetero-nanocrystals with reasonable design and flexible synthesis.
Carrier mobility is one of the key issues for applications of organic semiconductors in electronic and optoelectronic devices. Organic single crystals possess much higher carrier mobility compared to ...amorphous films. However, unipolar properties with unbalanced hole and electron transporting ability have been a bottleneck for the high performance of organic single crystal‐based devices. Here, well‐balanced ambipolar organic single crystals are developed by mixing of n‐ and p‐type molecules with maintained single‐crystalline structures. Carrier mobility of the ambipolar single crystals is manipulated by tuning the mixing ratio, and nearly equal hole and electron mobility can be achieved. Highly efficient single crystal‐based organic light‐emitting devices (OLEDs) are demonstrated by employing the ambipolar crystals as the mixed host for a red emitter pentacene to realize efficient exciton confinement and energy transfer within the emissive layer. As a result, maximum luminance of 5467 cd m−2 and current efficiency of 2.82 cd A−1 are achieved, which represents, to the best of the authors’ knowledge, the record performance for the organic single crystal‐based OLEDs to date. The strategy to manipulate the charge‐transport properties of the organic single crystals in this work represents a significant step toward practical applications of the organic single crystals in optoelectronics.
Well‐balanced ambipolar organic single crystals are developed by mixing n‐type BTPB and p‐type BSB‐Me molecules, and the hole and electron mobilities are manipulated to be nearly equal. Organic light‐emitting devices based on these ambipolar crystals exhibit a record luminance, current efficiency, and external quantum efficiency. The strategy to manipulate the charge‐transport properties of the organic single crystals in this work represents a significant step toward practical applications of the organic single crystals in optoelectronics.
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