Are social media posts with pictures more popular than those without? Why do pictures with certain characteristics induce higher engagement than some other pictures? Using data sets of social media ...posts about major airlines and sport utility vehicle brands collected from Twitter and Instagram, the authors empirically examine the influence of image content on social media engagement. After accounting for selection bias on the inclusion of image content, the authors find a significant and robust positive mere presence effect of image content on user engagement in both product categories on Twitter. They also find that high-quality and professionally shot pictures consistently lead to higher engagement on both platforms for both product categories. However, the effect of colorfulness varies by product category, while the presence of human face and image–text fit can induce higher user engagement on Twitter but not on Instagram. These findings shed light on how to improve social media engagement using image content.
Conversion of naturally abundant nitrogen to ammonia is a key (bio)chemical process to sustain life and represents a major challenge in chemistry and biology. Electrochemical reduction is emerging as ...a sustainable strategy for artificial nitrogen fixation at ambient conditions by tackling the hydrogen- and energy-intensive operations of the Haber-Bosch process. However, it is severely challenged by nitrogen activation and requires efficient catalysts for the nitrogen reduction reaction. Here we report that a boron carbide nanosheet acts as a metal-free catalyst for high-performance electrochemical nitrogen-to-ammonia fixation at ambient conditions. The catalyst can achieve a high ammonia yield of 26.57 μg h
mg
and a fairly high Faradaic efficiency of 15.95% at -0.75 V versus reversible hydrogen electrode, placing it among the most active aqueous-based nitrogen reduction reaction electrocatalysts. Notably, it also shows high electrochemical stability and excellent selectivity. The catalytic mechanism is assessed using density functional theory calculations.
Mortality from hepatitis B virus (HBV)–related acute‐on‐chronic liver failure (ACLF) is high due to limited treatment options. Preclinical and clinical investigations have proved that treatment with ...mesenchymal stromal cells (MSCs) is beneficial for recovery from liver injury. We hypothesized that the outcome of HBV‐related ACLF would be improved by MSC treatment. From 2010 to 2013, 110 patients with HBV‐related ACLF were enrolled in this open‐label, nonblinded randomized controlled study. The control group (n = 54) was treated with standard medical therapy (SMT) only. The experimental group (n = 56) was infused weekly for 4 weeks with 1.0 to 10 × 105 cells/kg allogeneic bone marrow–derived MSCs and then followed for 24 weeks. The cumulated survival rate of the MSC group was 73.2% (95% confidence interval 61.6%‐84.8%) versus 55.6% (95% confidence interval 42.3%‐68.9%) for the SMT group (P = 0.03). There were no infusion‐related side effects, but fever was more frequent in MSC compared to SMT patients during weeks 5‐24 of follow‐up. No carcinoma occurred in any trial patient in either group. Compared with the control group, allogeneic bone marrow–derived MSC treatment markedly improved clinical laboratory measurements, including serum total bilirubin and Model for End‐Stage Liver Disease scores. The incidence of severe infection in the MSC group was much lower than that in the SMT group (16.1% versus 33.3%, P = 0.04). Mortality from multiple organ failure and severe infection was higher in the SMT group than in the MSC group (37.0% versus 17.9%, P = 0.02). Conclusion: Peripheral infusion of allogeneic bone marrow–derived MSCs is safe and convenient for patients with HBV‐related ACLF and significantly increases the 24‐week survival rate by improving liver function and decreasing the incidence of severe infections. (Hepatology 2017;66:209–219).
Herein, we present a new strategy for the synthesis of 2D porous MoP/Mo2N heterojunction nanosheets based on the pyrolysis of 2D PMo12O403−‐melamine (PMo12‐MA) nanosheet precursor from a polyethylene ...glycol (PEG)‐mediated assembly route. The heterostructure nanosheets are ca. 20 nm thick and have plentiful pores (<5 nm). These structure features offer advantages to promote the HER activity, including the favorable water dissociation kinetics around heterojunction as confirmed by theoretical calculations, large accessible surface of 2D nanosheets, and enhanced mass‐transport ability by pores. Consequently, the 2D porous MoP/Mo2N heterojunction nanosheets exhibit excellent HER activity with low overpotentials of 89, 91 and 89 mV to achieve a current density of 10 mA cm−2 in alkaline, neutral and acidic electrolytes, respectively. The HER performance is superior to the commercial Pt/C at a current density >55 mA cm−2 in neutral medium and >190 mA cm−2 in alkaline medium.
2D porous MoP/Mo2N heterojunction nanosheets have been created based on a PEG‐mediated assembly strategy, which exhibit outstanding performance for HER over wide pH ranges even out‐performing the Pt/C benchmark at large current density. A series of tests and DFT calculations shows the synergy of the heterojunctions, pores and 2D nanosheets for promoting the HER performance.
Polymeric carbon nitride (C3N4) has emerged as the most promising candidate for metal-free photocatalysts but is plagued by low activity due to the poor quantum efficiency and low specific surface ...area. Exfoliation of bulk crystals into ultrathin nanosheets has proven to be an effective and widely used strategy for enabling high photocatalytic performances; however, this process is complicated, time-consuming, and costly. Here, we report a simple bottom-up method to synthesize porous few-layer C3N4, which involves molecule self-assembly into layered precursors, alcohol molecules intercalation, and subsequent thermal-induced exfoliation and polycondensation. The as-prepared few-layer C3N4 expose more active sites and greatly enhance the separation of charge carriers, thus exhibiting a 26-fold higher hydrogen evolution activity than bulk counterpart. Furthermore, we find that both the high activity and selectivity for the oxidative coupling of amines to imines can be obtained under visible light that surpass those of other metal-free photocatalysts so far.
The deep integration of higher education with digital technology represents an inevitable trend, and evaluating the interplay between higher education resources (HER) and digital infrastructure ...construction (DIC) holds significant value for advancing the development of digital higher education and mitigating regional disparities in China. This study establishes two comprehensive evaluation frameworks for HER and DIC. Panel data from 31 provinces, spanning the period from 2011 to 2020, are utilized for analysis. The coupling coordination degree (CCD) model is employed in this work to evaluate the synergy between HER and DIC in China. Furthermore, we analyze the regional differences, spatial distribution, and trend evolution of this synergy. The study results revealed that there is an initial decrease followed by an increase in the synergy between HER and DIC, and the overall CCD is at a moderate coordination, with the mean CCD of the eastern region being significantly higher than that of the other three regions, and the inter-regional difference is the main source of regional disparity in this synergy. The current state of synergistic development reveals a slight inclination towards multi-polarization, although the disparity in regional development was decreasing. Additionally, there is an observed convergence in the coordinated development of HER and DIC, with spatial factors playing a significant role. These findings offer empirical support for efforts to enhance the integration of HER and DIC, reduce regional disparities in higher education, and foster sustainable development in China's higher education sector.
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The Coronavirus Disease 2019 (COVID-19) has been declared as a global pandemic, but specific medicines and vaccines are still being developed. In China, interventional therapies with ...traditional Chinese medicine for COVID-19 have achieved significant clinical efficacies, but the underlying pharmacological mechanisms are still unclear. This article reviewed the etiology of COVID-19 and clinical efficacy. Both network pharmacological study and literature search were used to demonstrate the possible action mechanisms of Chinese medicines in treating COVID-19. We found that Chinese medicines played the role of antivirus, anti-inflammation and immunoregulation, and target organs protection in the management of COVID-19 by multiple components acting on multiple targets at multiple pathways. AEC2 and 3CL protein could be the direct targets for inhibiting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Quercetin, kaempferol, luteolin, isorhamnetin, baicalein, naringenin, and wogonin could be the main active ingredients of Chinese medicines for the management of COVID-19 by targeting on AEC2 and 3CL protein and inhibiting inflammatory mediators, regulating immunity, and eliminating free radicals through COX-2, CASP3, IL-6, MAPK1, MAPK14, MAPK8, and REAL in the signaling pathways of IL-17, arachidonic acid, HIF-1, NF-κB, Ras, and TNF. This study may provide meaningful and useful information on further research to investigate the action mechanisms of Chinese medicines against SARS-CoV-2 and also provide a basis for sharing the “China scheme" for COVID-19 treatment.
Overall water splitting driven by a low voltage is crucial for practical H2 evolution, but it is challenging. Herein, anion‐modulation of 3D Ni–V‐based transition metal interstitial compound (TMIC) ...heterojunctions supported on nickel foam (Ni3N‐VN/NF and Ni2P‐VP2/NF) as coupled hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysts for efficient overall water splitting is demonstrated. The heterointerface in Ni3N‐VN has a suitable H* absorption energy, being favorable for enhancing HER activity with onset overpotential (ηonset) of zero and Tafel slope of 37 mV dec−1 in 1 m KOH (close to that of Pt/C/NF). For the OER, the synergy of Ni2P‐VP2 with oxide species can give enhanced activity with ηonset of 220 mV and Tafel slope of 49 mV dec−1. The good activity is ascribed to heterointerface for activating the intermediates, good conductivity of TMICs for electron‐transfer, and porous structure facilitation of mass‐transport. Additionally, the minimal mutual influence of Ni3N‐VN/NF and Ni2P‐VP2/NF allows easy coupling for efficient overall water splitting with a low driving voltage (≥1.43 V), a voltage of 1.51 V at 10 mA cm−2, and remarkable durability for 100 h. It can be driven by a solar cell (1.5 V), indicating its potential to store intermittent energy.
An anion‐modulation strategy is presented to create 3D Ni–V interstitial compound heterojunctions (Ni3N–VN/nickel foam (NF) and Ni2P‐VP2/NF). The excellent hydrogen evolution reaction (HER) activity of Ni3N–VN/NF and oxygen evolution reaction (OER) activity of Ni2P–VP2/NF and minimal mutual influence make them easy to couple to achieve overall water splitting with a low driving voltage and remarkable stability.
In this paper, the influences of broken bars located at different relative positions in an induction motor are presented. In this investigation, a finite-element model of the squirrel-cage induction ...motor is developed. Both thermal and electromagnetic analysis of the induction motor operating in conditions of healthy and broken bars fault are carried out, and operating performance and thermal fields with two broken rotor bars located at different relative positions are studied. The accuracy of simulation is verified by experimental results derived from a prototype. From the results, some valuable ideas can be proposed to the broken bars' fault diagnosis.
Developing non‐precious‐metal bifunctional oxygen reduction and evolution reaction (ORR/OER) catalysts is a major task for promoting the reaction efficiency of Zn–air batteries. Co‐based catalysts ...have been regarded as promising ORR and OER catalysts owing to the multivalence characteristic of cobalt element. Herein, the synthesis of Co nanoislands rooted on Co–N–C nanosheets supported by carbon felts (Co/Co–N–C) is reported. Co nanosheets rooted on the carbon felt derived from electrodeposition are applied as the self‐template and cobalt source. The synergistic effect of metal Co islands with OER activity and Co–N–C nanosheets with superior ORR performance leads to good bifuctional catalytic performances. Wavelet transform extended X‐ray absorption fine spectroscopy and X‐ray photoelectron spectroscopy certify the formation of Co (mainly Co0) and the Co–N–C (mainly Co2+ and Co3+) structure. As the air‐cathode, the assembled aqueous Zn–air battery exhibits a small charge–discharge voltage gap (0.82 V@10 mA cm−2) and high power density of 132 mW cm−2, outperforming the commercial Pt/C catalyst. Additionally, the cable flexible rechargeable Zn–air battery exhibits excellent bendable and durability. Density functional theory calculation is combined with operando X‐ray absorption spectroscopy to further elucidate the active sites of oxygen reactions at the Co/Co–N–C cathode in Zn–air battery.
A 3D hierarchical self‐supported electrode composed of Co nanoislands and Co–N–C nanosheets is developed for highly efficient bifunctional oxygen reduction reaction/oxygen evolution reaction catalysts toward both liquid‐ and solidstate Zn–air batteries. Operando X‐ray absorption fine‐structure is combined with density functional theory calculation to further elucidate the active sites of oxygen reactions at the Co/Co–N–C cathode in Zn–air batteries.
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