Electron Deficient Ir-O Bonds Promote Heterogeneous Ir-Catalyzed Anti-Markovnikov Hydroboration of Alkenes under Mild Neat Conditions.

Tuning electronic characteristics of metal-ligand bonds based on reaction pathways to achieve efficient catalytic processes has been widely studied and proven to be feasible in homogeneous catalysis, but it is scarcely investigated in heterogeneous catalysis. Herein, we demonstrate the regulation of the electronic configuration of Ir-O bonds in an Ir single-atom catalyst according to the borane activation mechanism. Ir-O bonds in Ir1/Ni(OH)x are found to be more electron-poor than those in Ir1/NiOx. Despite the mild solvent-free conditions and ambient temperature, Ir1/Ni(OH)x exhibits outstanding performance for the hydroboration of alkenes, furnishing the desired alkylboronic esters with a turnover frequency value of ≤3060 h-1 and 99% anti-Markovnikov selectivity, which is significantly better than that of Ir1/NiOx (42 h-1). It is further proven that the more electron-poor Ir-O bonds as active centers are more oxidative and so benefit the activation of the H-B bond in the reductive pinacolborane.

Inserting Single-Atom Zn by Tannic Acid Confinement To Regulate the Selectivity of Pd Nanocatalysts for Hydrogenation Reactions.

Precisely controlling the selectivity of nanocatalysts has always been a hot topic in heterogeneous catalysis but remains difficult owing to their complex and inhomogeneous catalytic sites. Herein, an effective strategy to regulate the chemoselectivity of Pd nanocatalysts for selective hydrogenation reactions by inserting single-atom Zn into Pd nanoparticles is reported. Taking advantage of the tannic acid coating-confinement strategy, small-sized Pd nanoparticles with inserted single-atom Zn are obtained on the O-doped carbon-coated alumina. Compared with the pure Pd nanocatalyst, the Pd nanocatalyst with single-atom Zn insertion exhibits prominent selectivity for the hydrogenation of p-iodonitrobenzene to afford the hydrodeiodination product instead of nitro hydrogenation ones. Further computational studies reveal that the single-atom Zn on Pd nanoparticles strengthens the adsorption of the nitro group to avoid its reduction and increases the d-band center of Pd atoms to facilitate the reduction of the iodo group, which leads to enhanced selectivity. This work provides new guidelines to tune the selectivity of nanocatalysts with guest single-atom sites.

Promoting Active Aging Through Sports Participation: A Qualitative Exploration of Serious Leisure Among Older Chinese Adults.

China's population of older individuals reached 264.02 million in 2020, an increase of 5.44% from 2010. This study explores how participation in serious leisure sports, which have enduring benefits for older adults, contributes to active aging. In-depth interviews were conducted with 15 older participants aged 60-78 years who had participated in a leisure sport activity for 1 year or longer. A thematic analysis was conducted, and four themes emerged: body improvements, positive emotions, optimistic life attitudes, and social interactions. Older adults who participate in serious leisure sports are empowered via practice and learning opportunities to engage with their aging bodies, pursue psychological benefits, and jointly maintain leisure groups. The findings of this study contribute to our understanding of the "rights-based" approach to active aging and allow us to identify serious leisure sports as an active way for older adults to improve their quality of life.

The mediating role of psychological commitment between recreation specialization and life satisfaction: Evidence from Xiamen Marathon runners.

Although previous research spared no efforts to explain the life satisfaction of marathon runners, little was known about the relationship between recreation specialization (RS), life satisfaction (LS), psychological commitment (PC), and social support (SS). This study examines (i) how the dimension of RS (i.e., behavior, cognition, and affect) influences runners' PC and LS, and (ii) the mediating effects of PC and the moderating effects of SS on the relationship between behavior, cognition, affect, and LS. The results showed that behavior (ß = 0.15, p < 0.01), cognition (ß = 0.35, p < 0.001), affect (ß = 0.28, p < 0.001), and PC (ß = 0.59, p < 0.001) had significant and positive impacts on runners' LS; PC (Indirect path coefficient = 0.09 ~ 0.20) mediated the relationship between the dimensions of RS and LS. In addition, the results also confirmed the moderating effects of SS (ß = 0.10, p < 0.05) between affect dimension and LS. These findings offered more evidence for understanding how RS dimensions and PC influence runners' LS. Future research should integrate runner's leisure experiences to better understand the results revealed in this study.

The Role of Recreation Specialization and Self-Efficacy on Life Satisfaction: The Mediating Effect of Flow Experience.

Previous studies confirmed that leisure sport participation could contribute to people's life satisfaction. However, little is known about the predictors of life satisfaction in the context of long-distance running. A model was proposed in this study to examine the relationship between recreation specialization, self-efficacy, flow experience, and life satisfaction. An online questionnaire was distributed to long-distance runners in China, and a total of 404 valid questionnaires were obtained for data analysis in this study. Results indicated that recreation specialization and self-efficacy had a direct and positive effect on runners' flow experience; recreation specialization, self-efficacy, and flow experience were positively associated with runners' life satisfaction. Furthermore, flow experience partially mediated the relationship between self-efficacy and life satisfaction, while it fully mediated the role of recreation specialization in life satisfaction. The findings shed some new insights for understanding the influence of leisure sport engagement on people's life satisfaction.

Al3+ Dopants Induced Mg2+ Vacancies Stabilizing Single-Atom Cu Catalyst for Efficient Free-Radical Hydrophosphinylation of Alkenes.

Utilizing heterogeneous catalysts to overcome obstacles for homogeneous reactions is fascinating but very challenging owing to the difficult fabrication of such catalysts based on the character of target reactions. Herein, we report a Al3+ doping strategy to construct single-atom Cu on MgO nanosheets (Cu1/MgO(Al)) for boosting the free-radical hydrophosphinylation of alkenes. Al3+ dopants in MgO bring about abundant Mg2+ vacancies for stabilizing dense independent Cu atoms (6.3 wt %), while aggregated Cu nanoparticles are formed without Al3+ dopants (Cu/MgO). Cu1/MgO(Al) exhibits preeminent activity and durability in the hydrophosphinylation of various alkenes with great anti-Markovnikov selectivity (99%). The turnover frequency (TOF) value reaches up to 1272 h-1, exceeding those of Cu/MgO by ∼6-fold and of traditional homogeneous catalysts drastically. Further experimental and theoretical studies disclose that the prominent performance of Cu1/MgO(Al) derives from the accelerated initiating step of phosphinoyl radical triggered by individual Cu atoms.

Decreasing the coordinated N atoms in a single-atom Cu catalyst to achieve selective transfer hydrogenation of alkynes.

Single-atom (SA) catalysts have attracted broad attention due to their distinctive catalytic properties in diverse reactions. Increasing the unsaturated coordination sites of active centers is a valid and challenging approach to improve the performance of such catalysts. Herein, we report an oxide compounding strategy to decrease the N coordination number of a SA Cu catalyst by reducing the thickness of the N-doped carbon carrier with a lower density of N atoms. The SA Cu catalyst with a more unsaturated N coordination structure can achieve transfer hydrogenation of alkynes with good activity and selectivity, which is disabled over the common N coordinated SA Cu catalyst on pure CN. It is found that individual Cu centers coordinated by fewer N atoms can accelerate the hydrogen transfer from ammonia-borane and still leave proper adsorption sites for alkynes to realize the entire hydrogenation reaction. This work will open up new opportunities to modulate the unsaturated coordination structure of SA catalysts for creating better-performing heterogeneous catalysts.

Construction of Pd-Zn dual sites to enhance the performance for ethanol electro-oxidation reaction.

Rational design and synthesis of superior electrocatalysts for ethanol oxidation is crucial to practical applications of direct ethanol fuel cells. Here, we report that the construction of Pd-Zn dual sites with well exposure and uniformity can significantly improve the efficiency of ethanol electro-oxidation. Through synthetic method control, Pd-Zn dual sites on intermetallic PdZn nanoparticles, Pd-Pd sites on Pd nanoparticles and individual Pd sites are respectively obtained on the same N-doped carbon coated ZnO support. Compared with Pd-Pd sites and individual Pd sites, Pd-Zn dual sites display much higher activity for ethanol electro-oxidation, exceeding that of commercial Pd/C by a factor of ~24. Further computational studies disclose that Pd-Zn dual sites promote the adsorption of ethanol and hydroxide ion to optimize the electro-oxidation pathway with dramatically reduced energy barriers, leading to the superior activity. This work provides valuable clues for developing high-performance ethanol electro-oxidation catalysts for fuel cells.

The Impact of Cycling Specialization on Successful Aging and the Mediating Role of Loneliness.

Recent studies have provided some evidence supporting that cycling specialization (CS) may be positively related to successful aging (SA) among elderly adults. However, there is a gap regarding the examination of the role of loneliness in the relationship between CS and SA. A hypothetical model was proposed to test the relationship between CS, SA, and loneliness. For this purpose, this study randomly conducted a questionnaire survey among 395 cycling participants over the age of 60 in China. The results showed that behavior, cognition, and affect had negative effects on loneliness. Behavior, cognition, and affect were positively associated with SA. Loneliness was negatively related to SA. Furthermore, behavior, cognition, and affect had positive and indirect effects on SA through loneliness. These results offered some new insights for understanding the relationship between CS and SA, especially considering the indirect effect of loneliness. The limitations and implications of the findings were discussed.

Women Runners in China: Constraints Negotiation Process of Serious Leisure.

The constraint negotiation process is a prominent part of serious leisure, and leisure-oriented women runners in China may behave differently in this process. An adjusted model was proposed to examine the constraint negotiation process of serious leisure for women runners. An online questionnaire was conducted that contained 239 valid samples measuring the participation, intrinsic motivation, constraints and negotiation of women runners. The structure of variables was confirmed based on the good results of reliability and validity test. Then the structural equation modeling results showed that constraints had a negative impact and negotiation had a positive impact on participation. Negotiation acts on constraints to reduce their negative perception. Furthermore, intrinsic motivation has a significant positive effect on negotiation. There are high intrinsic motivation and fewer constraints reporting for women runners under high negotiation in serious leisure. The results provide additional explanation for the serious leisure participation of women runners. Future research should integrate women's life experiences to better understand the behavior revealed in this study.

Heterogeneous modification of through-hole microwell chips for ultralow cross-contamination digital polymerase chain reaction.

Chip-based dPCR (cdPCR) with a physical boundary between micro-units allows for high parallelism, robustness and sensitivity. However, cross-contamination between micro-units is still a problem that affects the accuracy of results. To overcome this problem, we introduced a heterogeneous modification strategy by microcontact printing to prepare a through-hole microwell chip (TMC) with a hydrophobic exterior surface and hydrophilic interior surface. The modified TMC can reduce cross-contamination (sample residual rate (SRR) of (4.9 ± 1.5)%) by an efficient partitioning yield (unit filling rate (UFR) of (91.1 ± 2.2)%). The sample-residual properties of modified TMCs could be tuned by the reaction conditions. As the contact time increased, the surface CA of the TMC increased, which caused decreases of the SRR and UFR. However, prolonging the contact time to 25 s would cause a sharp reduction of the UFR. The modified TMCs with high UFRs were used for further dPCR studies. The fluorescence images of dPCR chips were collected by fluorescence microscopy and a self-developed optical system, followed by image processing and data statistics to obtain quantitative results. The copy number variation results of the surface hydrophobic TMC was closer to the true value compared to that of the hydrophilic TMC. The results indicated that the sample residue on the hydrophilic TMC would increase the number of positive points, which would cause false positives and clustering error. The absolute quantitative results of gradient dilution plasmid DNA of JAK2 gene using modified TMC also proved that heterogeneous modification made the quantitative results more accurate. The heterogeneous modified TMC is expected to be used for high-throughput, high-sensitivity and high-specificity biological analyses, such as circulating tumor DNA and cell analysis.

[Determination of diflubenzuron and triflumuron residues in greasy wool by accelerated solvent extraction technique and high performance liquid chromatography].

A method for the determination of diflubenzuron and triflumuron residues in greasy wool was developed by high performance liquid chromatography (HPLC) coupled with accelerated solvent extraction (ASE). The diflubenzuron and triflumuron residues were extracted with acetonitrile saturated with n-hexane at 80 degrees C and 10.34 MPa. The extract was pretreated by a series of procedures such as freezing-lipid filtration, concentration and purification by solid-phase extraction prior to the determination with HPLC. The target analytes were separated on a Waters Atlants dC18 column (250 mm x 4.6 mm, 5 microm), gradiently eluted with acetonitrile and water as the mobile phases and detected by a photodiode array detector (DAD) at 254 nm. The linear ranges were 0.1 - 10.0 mg/L. There were good linearity between the peak areas and concentrations in the linear range for the analytes, and the correlation coefficients of diflubenzuron and triflumuron were higher than 0.9999. The limits of quantification for diflubenzuron and triflumuron were 0.05 and 0.04 mg/kg (S/N > or = 10), respectively. The method is simple, rapid, sensitive and suitable for preliminary screening of diflubenzuron and triflumuron residues in greasy wool.

[Determination of 28 organochlorine and synthetic pyrethroid pesticides in greasy wool using accelerated solvent extraction technique and gas chromatography].

A method for the simultaneous determination of 28 organochlorine and synthetic pyrethroid pesticides in greasy wool was developed by accelerated solvent extraction (ASE) coupled with gas chromatography-electron capture detection (GC-ECD). The organochlorine and synthetic pyrethroid pesticides in greasy wool were extracted with acetonitrile saturated with n-hexane at 80 degrees C, 10.34 MPa by ASE. The extract was pretreated by a series of procedures such as freezing-lipid filtration, concentration and purification by solid-phase extraction prior to the determination with GC-ECD. The linear ranges were 0.005-1.0 mg/L for 16 organochlorines, 0.02-4.0 mg/L for flumethrin and 0.01-2.0 mg/L for the others. There were good linear relationships between the peak area and concentration in the linear ranges. The average recoveries of 28 organochlorine and synthetic pyrethroid pesticides were 67.2%-107.7%, and the relative standard deviations were 2.6%-29.0%. The method is simple, sensitive and suitable for preliminary screening of organochlorine and synthetic pyrethroid pesticides in greasy wool.