Half-Heusler thermoelectric materials have been attracting extensive research interest over the last two decades. In this mini-review article, we summarize the synthesis methods for optimizing ...individual parameters to enhance the thermoelectric performance in both MNiSn (n-type) and MCoSb (p-type) based half-Heuslers. Some more recently available approaches, such as using metallic phase nanoinclusions as dopants to enhance electrical conductivity and low energy carrier filtering to enhance Seebeck coefficient, resonant states near Fermi level for a higher Seebeck coefficient, and nanosized grains formed by rapid hot pressing to reduce thermal conductivity, are discussed in this article. In addition, the effect of high temperature annealing is also discussed, which is important for device performance.
Photocatalytic production of H2O2 from the reduction of O2 by semiconductor photocatalysts (e.g., graphitic carbon nitride, C3N4) has been regarded as an alternative for small-scale decentralized ...H2O2 production. However, the efficiency of pristine C3N4 photocatalysts is still limited by the narrow light absorption range and rapid charge recombination. Here, we presented a facile approach to simultaneously enhance the light absorption and promote the charge separation by introducing alkali metal dopants and N vacancies on C3N4. The introduction of alkali metal dopants and N vacancies successfully broadened the light absorption range, reduced the band gap from 2.85 to 2.63 eV, and greatly inhibited the charge recombination. The synergistic effect of doping and defect resulted in the improvement of photocatalytic performance with a H2O2 production rate of 10.2 mmol/h/g, which is 89.5 times that of pristine C3N4. Thus, this work not only gives insights into the synergistic effect of doping and defect for simultaneously manipulating the light absorption and charge separation processes but also inspires further work to develop more efficient photocatalysts for H2O2 production.
Electrochemical reduction of CO2 is an attractive technique for reducing CO2 emission and converting it into useful chemicals, but it suffers from high overpotential, low efficiency or poor product ...selectivity. Here, N-doped nanodiamond/Si rod array (NDD/Si RA) was proposed as an efficient nonmetallic electrocatalyst for CO2 reduction. It preferentially and rapidly converted CO2 to acetate over formate with an onset potential of −0.36 V (vs RHE), overcoming the usual limitation of low selectivity for C2 products. Moreover, faradic efficiency of 91.2–91.8% has been achieved for CO2 reduction at −0.8 to −1.0 V. Its superior performance for CO2 reduction can be attributed to its high overpotential for hydrogen evolution and N doping, where N-sp3C species was highly active for CO2 reduction. Electrokinetic data and in situ infrared spectrum revealed the main pathway for CO2 reduction might be CO2 → CO2 •– → (COO)2 • → CH3COO–.
Because of the absence of methods for tracking RNA G‐quadruplex dynamics, especially the folding and unfolding of this attractive structure in live cells, understanding of the biological roles of RNA ...G‐quadruplexes is so far limited. Herein, we report a new red‐emitting fluorescent probe, QUMA‐1, for the selective, continuous, and real‐time visualization of RNA G‐quadruplexes in live cells. The applications of QUMA‐1 in several previously intractable applications, including live‐cell imaging of the dynamic folding, unfolding, and movement of RNA G‐quadruplexes and the visualization of the unwinding of RNA G‐quadruplexes by RNA helicase have been demonstrated. Notably, our real‐time results revealed the complexity of the dynamics of RNA G‐quadruplexes in live cells. We anticipate that the further application of QUMA‐1 in combination with appropriate biological and imaging methods to explore the dynamics of RNA G‐quadruplexes will uncover more information about the biological roles of RNA G‐quadruplexes.
Flexing 'plexes: A new fluorescent probe, QUMA‐1, for the selective, continuous, and real‐time imaging of RNA G‐quadruplexes in live cells is reported. The use of QUMA‐1 in previously inaccesible applications, including live‐cell imaging of RNA G‐quadruplex dynamics and the visualization of the unwinding of RNA G‐quadruplexes by RNA helicase is demonstrated.
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Development of nanocarriers for drug delivery has received considerable attention due to their potential in achieving targeted delivery to the diseased site while sparing the ...surrounding healthy tissue. Safe and efficient drug delivery has always been a challenge in medicine. During the last decade, a large amount of interest has been drawn on the fabrication of surfactant-based vesicles to improve drug delivery. Niosomes are self-assembled vesicular nano-carriers formed by hydration of non-ionic surfactant, cholesterol or other amphiphilic molecules that serve as a versatile drug delivery system with a variety of applications ranging from dermal delivery to brain-targeted delivery. A large number of research articles have been published reporting their fabrication methods and applications in pharmaceutical and cosmetic fields. Niosomes have the same advantages as liposomes, such as the ability to incorporate both hydrophilic and lipophilic compounds. Besides, niosomes can be fabricated with simple methods, require less production cost and are stable over an extended period, thus overcoming the major drawbacks of liposomes. This review provides a comprehensive summary of niosomal research to date, it provides a detailed overview of the formulation components, types of niosomes, effects of components on the formation of niosomes, fabrication and purification methods, physical characterization techniques of niosomes, recent applications in pharmaceutical field such as in oral, ocular, topical, pulmonary, parental and transmucosal drug delivery, and cosmetic applications. Finally, limitations and the future outlook for this delivery system have also been discussed.
Purpose
This paper studied whether boredom at home due to social isolation during the COVID-19 pandemic may motivate individuals to engage in online leisure crafting, thereby contributing to their ...thriving at home and career self-management. This paper aims to examine whether individuals’ growth need strength influences the impact of home boredom on online leisure crafting.
Design/methodology/approach
This paper performed a two-wave longitudinal study involving a group of employees from the hospitality industry (N = 340) in Mainland China. This paper evaluated home boredom, online leisure crafting and growth need strength at Time 1 and thriving at home and career self-management two months later at Time 2.
Findings
The respondents’ experience of home boredom had a time-lagged effect on their thriving at home and career self-management via online leisure crafting. Additionally, their growth need strength amplified the positive impact of home boredom on online leisure crafting.
Practical implications
Hospitality managers can motivate employees to engage in crafting online leisure activities at home when they experience home boredom during the outbreak of COVID-19, which may further allow them to experience thriving at home and engage in career self-management. Additionally, managers can develop managerial interventions to improve the growth need strength of employees with low growth needs, which may, in turn, render these employees less likely to tolerate home boredom, thereby increasing the positive impact of home boredom on their online leisure crafting.
Originality/value
This paper offer insights for the boredom literature regarding how individuals’ home boredom caused by social isolation during the COVID-19 pandemic might lead to their thriving at home through online leisure crafting. This paper also provides insights for the leisure crafting literature regarding the role of online leisure crafting in individuals’ thriving at home. This paper reveals the role of growth need strength in the impact of home boredom on thriving at home through online leisure crafting.
Furfural and 5-hydroxymethylfurfural stand out as bridges connecting biomass raw materials to the biorefinery industry. Their reductive transformations by hydroconversion are key routes toward a wide ...variety of chemicals and biofuels, and heterogeneous catalysis plays a central role in these reactions. The catalyst efficiency highly depends on the nature of metals, supports, and additives, on the catalyst preparation procedure, and obviously on reaction conditions to which catalyst and reactants are exposed: solvent, pressure, and temperature. The present review focuses on the roles played by the catalyst at the molecular level in the hydroconversion of furfural and 5-hydroxymethylfurfural in the gas or liquid phases, including catalytic hydrogen transfer routes and electro/photoreduction, into oxygenates or hydrocarbons (e.g., furfuryl alcohol, 2,5-bis(hydroxymethyl)furan, cyclopentanone, 1,5-pentanediol, 2-methylfuran, 2,5-dimethylfuran, furan, furfuryl ethers, etc.). The mechanism of adsorption of the reactant and the mechanism of the reaction of hydroconversion are correlated to the specificities of each active metal, both noble (Pt, Pd, Ru, Au, Rh, and Ir) and non-noble (Ni, Cu, Co, Mo, and Fe), with an emphasis on the role of the support and of additives on catalytic performances (conversion, yield, and stability). The reusability of catalytic systems (deactivation mechanism, protection, and regeneration methods) is also discussed.
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•MIL-88B-Fe exhibited high catalytic activity and stability in Fenton-like processes.•Coordinatively unsaturated irons were the active sites of MIL-88B-Fe.•Contact of H2O2 with the ...active sites was necessary for the Fenton-like reaction.•Enhanced Fe(III)/Fe(II) redox cycle of MIL-88B-Fe contributed to its high catalytic activity.
The Fenton reaction is an efficient technology for degrading refractory organic pollutants in water. Heterogeneous Fenton-like catalysts have been demonstrated to be promising alternatives to homogeneous catalysts because of their reusability and lack of sludge production. These catalysts, however, generally show low activity for generating OH due to their limited exposed active sites and difficulty in the reduction of Fe(III) to Fe(II). Here, enhanced catalytic performance was achieved by using an iron-based metal organic framework (MIL-88B-Fe) as a heterogeneous Fenton-like catalyst over a wide pH range (4–6). The catalytic activity of MIL-88B-Fe was about 1–3 orders of magnitude higher than that of three other conventional catalysts (Fe2O3, α-FeOOH, and Fe3O4) and two other iron-based MOFs (MIL-53-Fe and MIL-101-Fe). The superior activity of MIL-88B-Fe could originate from the abundance of active sites, the flexible structure, and facilitated reduction of Fe(III) to Fe(II). Hydroxyl radicals generated from reaction between MIL-88B-Fe and H2O2 were the main reactive oxidative species for phenol degradation.
H2O2 production by electroreduction of O2 is an attractive alternative to the current anthraquinone process, which is highly desirable for chemical industries and environmental remediation. However, ...it remains a great challenge to develop cost‐effective electrocatalysts for H2O2 synthesis. Here, hierarchically porous carbon (HPC) was proposed for the electrosynthesis of H2O2 from O2 reduction. It exhibited high activity for O2 reduction and good H2O2 selectivity (95.0–70.2 %, most of them >90.0 % at pH 1–4 and >80.0 % at pH 7). High‐yield H2O2 generation has been achieved on HPC with H2O2 concentrations of 222.6–62.0 mmol L−1 (2.5 h) and corresponding H2O2 production rates of 395.7–110.2 mmol h−1 g−1 at pH 1–7 and −0.5 V. Moreover, HPC was energy‐efficient for H2O2 production with current efficiency of 81.8–70.8 %. The exceptional performance of HPC for electrosynthesis of H2O2 could be attributed to its high content of sp3‐C and defects, large surface area and fast mass transfer.
The electroreduction of O2 is achieved with hierarchically porous carbon (HPC) to give H2O2. It exhibits good selectivity, a high production rate, and current efficiency for the electrosynthesis of H2O2 at a wide range of pH values. The correlation between H2O2 production rate and sp3‐C atoms and defects was explored. This provides an effective method for tuning the activity of carbon materials for the selective electrosynthesis of H2O2. RE=reference electrode.
This study explores why some fake news publishers are able to propagate misinformation while others receive little attention on social media. Using COVID-19 vaccine tweets as a case study, this study ...combined the relational niche framework with pooled and multilevel models that address the unobserved heterogeneity. The results showed that, as expected, ties to accounts with more followers were associated with more fake news tweets, retweets, and likes. However, more surprisingly, embedding with fake news publishers had an inverted U-shaped association with diffusion, whereas social proximity to mainstream media was positively associated. Although the effect of influential users is in line with opinion leader theory, the newly-identified effects of social proximity to reliable sources and embeddedness suggest that the key to fake news virality is to earn greater organizational status and modest, not overly, echo chambers. This study highlights the potential of dynamic media networks to shape the misinformation market.
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