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INTRODUCTION: Numerous studies have found that expert players anticipate better than novices. If more accurate prediction represents performance monitoring of experts, what are the advantages of elite basketball players in identifying and processing available cues? There is still a lack of sufficient evidence. This study examined the visual search in basketball players and explored the performance monitoring of action anticipation, adopting an expert-novice paradigm and eye-movement technology. METHODS: Forty basketball players were recruited in this study: 20 in the expert group and 20 in the novice group. Participants were asked to predict the outcome of videotaped basketball throws and their accuracy and eye-movement characteristics were record. RESULTS: The accuracy of the expert was significantly higher than that of the novice. The experts were able to instantly search and identify important cues in anticipation, and the gaze area of the experts was concentrated on the area of interest of the body. Additionally, the expert group showed long, repetitive, and rapid visual search of vital information, and improved their performance of the task. CONCLUSION: The experts could monitor the performance of prediction by grabbing vital shooting information (such as the body of a player). The results suggest the athletes and coaches that if they want to improve the ability of prediction, it may be useful to shift their focus of attention from ball trajectory to body action.
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Basquetebol , Desempenho Psicomotor , Humanos , Movimentos Oculares , Atletas , Sinais (Psicologia)RESUMO
Physical activity (PA) benefits children with autism spectrum disorder (ASD). Evidence suggests that some barriers impede parents from providing PA support for their children with ASD. Parental perceived stigma is one of these barriers. However, few studies have explored how parental perceived stigma influences parental PA support. This study aimed to investigate the relationship between parental perceived stigma and parental PA support, the mediating role of parental self-efficacy, and the moderating effect of having other typically developing children or not. A total of 274 participants were recruited to participate in the study. The results showed that parental self-efficacy mediated the association between parental perceived stigma and parental PA support and the moderating effect of having other typically developing children or not.
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A boryl radical-promoted dehydroxylative alkylation of 3-hydroxy-oxindole derivatives is achieved. The reaction starts from addition of 4-dimethylaminopyridine (DMAP)-boryl radical to the amide carbonyl oxygen atom, which induces a spin-center shift process to promote the C-O bond cleavage. The elimination of a hydroxide anion from a free hydroxy group is also accomplished. Capture of the generated carbon radical with alkenes furnishes a variety of C-3 alkylated oxindoles. This method features a simple operation and broad substrate scope.
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ConspectusThe past decades have witnessed tremendous progress on radical reactions. However, in comparison with carbon, nitrogen, oxygen, and other main group element centered radicals, the synthetic chemistry of boron centered radicals was less studied, mainly due to the high electron-deficiency and instability of such 3-center-5-electron species. In the 1980s, Roberts and co-workers found that the coordination of a Lewis base (amines or phosphines) with the boron center could form 4-center-7-electron boryl radicals (Lewis base-boryl radicals, LBRs) that are found to be more stable. However, only limited synthetic applications were developed. In 2008, Curran and co-workers achieved a breakthrough with the discovery of N-heterocyclic carbene (NHC) boryl radicals, which could enable a range of radical reduction and polymerization reactions. Despite these exciting findings, more powerful and valuable synthetic applications of LBRs would be expected, given that the structures and reactivities of LBRs could be easily modulated, which would provide ample opportunities to discover new reactions. In this Account, a summary of our key contributions in LBR-enabled radical borylation reactions and selective activation of inert carbon-heteroatom bonds will be presented.Organoboron compounds have shown versatile applications in chemical society, and their syntheses rely principally on ionic borylation reactions. The development of mechanistically different radical borylation reactions allows synthesizing products that are inaccessible by traditional methods. For this purpose, we progressively developed a series of NHC-boryl radical mediated chemo-, regio-, and stereoselective radical borylation reactions of alkenes and alkynes, by which a wide variety of structurally diverse organoboron molecules were successfully prepared. The synthetic utility of these borylated products was also demonstrated. Furthermore, we disclosed a photoredox protocol for oxidative generation of NHC-boryl radicals, which enabled useful defluoroborylation and arylboration reactions.Selective bond activation is an ideal way to convert simple starting materials to value-added products, while the cleavage of inert chemical bonds, in particular the chemoselectivity control when multiple identical bonds are present in similar chemical environments, remains a long-standing challenge. We envisaged that finely tuning the properties of LBRs might provide a new solution to address this challenge. Recently, we disclosed a 4-dimethylaminopyridine (DMAP)-boryl radical promoted sequential C-F bond functionalization of trifluoroacetic acid derivatives, in which the α-C-F bonds were selectively snipped via a spin-center shift mechanism. This strategy enables facile conversion of abundantly available trifluoroacetic acid to highly valuable mono- and difluorinated molecules. Encouraged by this finding, we further developed a boryl radical enabled three-step sequence to construct all-carbon quaternary centers from a range of trichloromethyl groups, where the three C-Cl bonds were selectively cleaved by the rational choice of suitable boryl radical precursors in each step. Furthermore, a boryl radical promoted dehydroxylative alkylation of α-hydroxy carboxylic acid derivatives was achieved, allowing for the efficient conversion of some biomass platform molecules to high value products.
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Enantioselective [2 + 2] cyclization between an imine and a carbon-carbon double bond is a versatile strategy to build chiral azetidines. However, α-branched allenoates have never been successfully applied in [2 + 2] cyclization reactions with imines, as they always undergo Kwon's [4 + 2] annulation in previous catalytic methods. Herein, a simple in situ generated magnesium catalyst was employed to successfully achieve the enantioselective [2 + 2] cyclization reaction of DPP-imines and α-branched allenoates for the first time. Insightful experiments including KIE experiments, controlled experiments, Hammett plot analysis, and 31P NMR studies of initial intermediates indicate that the current [2 + 2] cyclization of imine most likely involves an asynchronous concerted transition state. Further mechanistic investigations by combining kinetic studies, ESI experiments, 31P NMR studies of coordination complexes, and controlled experiments on reaction rates under different catalyst loading amounts provided the coordination details for this [2 + 2] cyclization reaction between DPP-imines and α-branched allenoates. This new approach was applied to the synthesis of various chiral aza-heterocycles, including the enantioselective synthesis of the key intermediate of a lipid-lowering agent Ezetimibe.
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Iminas , Magnésio , Reação de Cicloadição , Estrutura Molecular , Iminas/química , Estereoisomerismo , Cinética , Catálise , CarbonoRESUMO
This study draws upon a large sample of Chinese college students to examine the chain mediating roles of social interaction anxiety and loneliness in the relation between autistic traits and excessive smartphone use. To test our hypothesis that social interaction anxiety and loneliness mediate the relation between autistic traits and excessive smartphone use, we recruited a sample of 1103 college students and asked them to complete an assessment that measured the degrees of autistic traits, social interaction anxiety, loneliness, and excessive smartphone use. The results showed significant correlations among these variables. More autistic traits, which are correlated with higher levels of social interaction anxiety and higher levels of loneliness, were found to be associated with excessive smartphone use. In conclusion, this study highlights the need for screening for excessive smartphone use among college students who demonstrate autistic traits. Social interaction anxiety and loneliness show great potential in screening for excessive smartphone use among college students with high levels of autistic traits. We discuss the practical implications of the findings and directions for future study.
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Transtorno Autístico , Solidão , Humanos , Smartphone , Interação Social , Transtorno Autístico/diagnóstico , Ansiedade , Estudantes , ChinaRESUMO
A strategically distinct dehydroxylative alkylation reaction of α-hydroxy carboxylic acid derivatives with alkenes is developed. The reaction starts with the attack of a 4-dimethylaminopyridine (DMAP)-boryl radical to the carbonyl oxygen atom, followed by a spin-center shift (SCS) to trigger the C-O bond scission. The resulting α-carbonyl radicals couple with a wide range of alkenes to furnish various alkylated products. This strategy allows for the efficient conversion of a wide array of α-hydroxy amides and esters derived from several biomass molecules and natural products to value-added compounds. Experimental and computational studies verified the reaction mechanism.
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Alcenos , Ésteres , Alcenos/química , Alquilação , AmidasRESUMO
Objective: To explore characteristics of the species structure of the genus Bifidobacterium at different levels of blood glucose and lipid in middle-aged and older adults in Chengdu so as to provide research basis for applying bifidobacteria in the prevention and treatment of hyperglycemia and dyslipidemia. Methods: A total of 289 middle-aged and older adults of 45 and older were recruited in Chengdu between April and August 2018. They were divided into the healthy group, the dyslipidemia group, the hyperglycemia group, and the combination group (of subjects with both dyslipidemia and hyperglycemia). The levels of their fasting blood glucose (GLU), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were examined. In addition, stool samples were collected and real-time fluorescence quantitative PCR was used for quantitative analysis of the genus Bifidobacteriumand the 8 bifidobacteria most commonly found in human intestines, the results of which were then examined to identify their correlation to blood glucose and lipid levels. Results: A total of 289 samples were collected and findings of inter-group comparison of the species structure of Bifidobacterium were as follows: 1) findings regarding the Bifidobacterium species examined--there was no significant difference between groups in the detection rate and the number of species detected; the quantity of B. angulatum was significantly higher in the dyslipidemia group than that in the healthy group and that in the combination group, the quantify of B. catenulatum was significantly higher in the hyperglycemia group than that in the healthy group, and the quantity of B. dentium was significantly higher in the dyslipidemia group than that in the combination group. 2) Findings regarding the correlation between the quantity of bifidobacteria and blood glucose and lipid--at the genus level, only the dyslipidemia group showed negative correlation (r=-0.346) between Bifidobacterium and TC. At the species level, B. bifidum was negatively correlated with TG (r=-0.761), B. breve was negatively correlated with GLU, TC, and LDL-C (r=-0.256, r=-0.261, and r=-0.362), B.dentium was positively correlated with GLU (r=0.206), and B. infantis was negatively correlated with TC (r=-0.334) in the healthy group. In the hyperglycemia group, B. catenulatum and B. infantis were both positively correlated with HDL-C (r=0.307 and r=0.525). In the combination group, B. bifidum was negatively correlated with HDL-C (r=-0.828), while B. breve was positively correlated with TG and HDL-C (r=0.427 and r=0.375). Conclusion: Middle-aged and older adults with dyslipidemia and/or hyperglycemia were significantly different from healthy subjects in their testing results for Bifidobacterium. Compared with the structure of Bifidobacterium species, the changes in the number of Bifidobacterium species detected were more closely correlated to the levels of blood glucose and blood lipid, showing unique characteristics in different situations, which may indicate potential application as indicators for glucose and lipid metabolism.
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Glicemia , Hiperglicemia , Idoso , Bifidobacterium/genética , Humanos , Intestinos , Lipídeos , Pessoa de Meia-IdadeRESUMO
Defluorinative functionalization of readily accessible trifluoromethyl groups constitutes an economical route to partially fluorinated molecules. However, the controllable replacement of one or two fluorine atoms while maintaining high chemoselectivity remains a formidable challenge. Here we describe a general strategy for sequential carbon-fluorine (C-F) bond functionalizations of trifluoroacetamides and trifluoroacetates. The reaction begins with the activation of a carbonyl oxygen atom by a 4-dimethylaminopyridine-boryl radical, followed by a spin-center shift to trigger the C-F bond scission. A chemoselectivity-controllable two-stage process enables sequential generation of difluoro- and monofluoroalkyl radicals, which are selectively functionalized with different radical traps to afford diverse fluorinated products. The reaction mechanism and the origin of chemoselectivity were established by experimental and computational approaches.
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Conjugated ynones are easily accessible feedstock and the existence of an alkyne bond endows ynones with different attractive reactivities, thus making them unique substrates for catalytic asymmetric reactions. Their compatibility under organocatalytic, metal-catalyzed as well as cooperative catalytic conditions has resulted in numerous enantioselective transformations. Importantly, conjugated ynones can act as nucleophiles or electrophiles, and serve as easily accessed synthons for different cyclization pathways. This review summarizes the recent literature examples of the catalytic reactions of conjugated ynones and related compounds such as alkyne conjugated α-ketoesters, and classifies these reaction types alongside mechanistic insights whenever possible. We aim to trigger more intensive research in the future to render the asymmetric transformation of ynones as a common and reliable tool for asymmetric synthesis.
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Chiral magnesium catalyzed intramolecular vinylogous Michael reaction of novel cyclohexadienones via a desymmetrization process is reported. (R)-BINOL derived ligand and an achiral amide were employed in the current in situ generated magnesium catalyst, giving the corresponding hydrogenated benzofuranone skeletons in good to excellent enantioselectivities with high yields. This simple and efficient strategy could be utilized for the synthesis of aromatized α,ß-unsaturated ester and Br-substituted hydrogenated benzofuranone in good yields under mild conditions.
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Ball-milling is considered as an economical and simple technology to produce novel engineered materials. The ball-milled microscale zero valent iron/pyrite composite (BM-ZVI/FeS2) had been synthesized through ball-milling technology and applied for highly efficient sequestration of antimonate (Sb(V)) in aqueous solution. BM-ZVI/FeS2 exhibited good Sb(V) removal efficiency (≥ 99.18%) at initial concentration less than 100 mg Sb(V)/L. Compared to ball-milled zero valent iron (ZVI) and pyrite (FeS2), BM-ZVI/FeS2 exhibited extremely higher removal efficiency due to the good synergistic adsorption effect. BM-ZVI/FeS2 showed efficient removal performance at broad pH (2.6-10.6). Moreover, the coexisting anions had negligible inhibition influence on the Sb(V) removal. The antimony mine wastewater can be efficiently remediated by BM-ZVI/FeS2, and the residual Sb(V) concentrations (< 0.96 µg/L) can meet the mandatory discharge limit in drinking water (5 µg Sb/L). Experimental and model results demonstrated that endothermic reaction and chemisorption were involved in Sb(V) removal by BM-ZVI/FeS2. The XRD and XPS analyses confirmed that the complete corrosion of ZVI occurred on BM-ZVI/FeS2 after Sb(V) adsorption, resulting in the enhanced Sb(V) sequestration. Mechanism analyses showed that the excellent removal performance of BM-ZVI/FeS2 was ascribed to the high coverage of iron (hydr)oxide oxidized from ZVI. Because of the advantages of economical cost, high Sb(V) removal capacity and easy availability, BM-ZVI/FeS2 offers a promising adsorbent for Sb(V) remediation.
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Poluentes Químicos da Água/análise , Adsorção , Ferro , SulfetosRESUMO
A series of 2-(cyanomethyl)azaarenes containing benzothiazole or benzoxazole were designed and synthesized for asymmetric α-functionalization with N-Boc-amino sulfones. The Mannich adducts were obtained in high yields with good diastereo- and enantioselectivities. Aryl-substituted amino sulfones were tolerated under the current conditions, and the reaction can be performed on gram scale in good results.