Publications by authors named "Xiao Yang Dong"

Purpose: This study analyzes the relationship between human papillomavirus (HPV) infection, vaginal microecology, and cervical lesions to provide a basis for the prevention and treatment of cervical cancer (CC) in the Xinjiang region.

Methods: Real-time quantitative PCR was used for HPV genotyping and viral load. The Gram staining and dry biochemical enzyme kit were utilized to diagnose vaginal secretions.

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Chiral amines are commonly used in the pharmaceutical and agrochemical industries. The strong demand for unnatural chiral amines has driven the development of catalytic asymmetric methods. Although the N-alkylation of aliphatic amines with alkyl halides has been widely adopted for over 100 years, catalyst poisoning and unfettered reactivity have been preventing the development of a catalyst-controlled enantioselective version.

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Introduction: Disorders of consciousness (DoCs) are a frequent complication of brain injury disease, and effective treatments are currently lacking. Transauricular vagus nerve stimulation (tVNS) has been proposed as a promising therapeutic method for neurological disorders such as epilepsy and depression. In our previous study, we demonstrated that vagus nerve stimulation promoted recovery in rats with DoCs caused by traumatic brain injury.

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Objectives: This study aimed to assess the efficacy and safety of probiotics for Helicobacter pylori (H. pylori) eradication therapy as well as their effects on gastric microbiota.

Methods: Patients who had failed H.

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The enantioconvergent cross-coupling of racemic alkyl halides represents a powerful tool for the synthesis of enantioenriched molecules. In this regard, the first-row transition metal catalysis provides a suitable mechanism for stereoconvergence by converting racemic alkyl halides to prochiral radical intermediates owing to their good single-electron transfer ability. In contrast to the noble development of chiral nickel catalyst, copper-catalyzed enantioconvergent radical cross-coupling of alkyl halides is less studied.

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In contrast with the well-established enantioconvergent radical C(sp)-C cross-coupling of racemic secondary alkyl electrophiles, the corresponding coupling of tertiary electrophiles to forge all-carbon quaternary stereocentres remains underexplored. The major challenge arises from the steric hindrance and the difficult enantio-differentiation of three distinct carbon substituents of prochiral tertiary radicals. Here we demonstrate a general copper-catalysed enantioconvergent C(sp)-C(sp) cross-coupling of diverse racemic tertiary alkyl halides with terminal alkynes (87 examples).

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α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions.

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Objectives: The objective was to examine care willingness and demand of residents under 60 years of age after retirement.

Setting: The staged cluster sampling method was used between August and October 2018 in Dujiangyan, Sichuan Province, China.

Participants: 2282 participants under 60 years of age were surveyed in 2018 by the staged cluster sampling method in China.

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Objective: To investigate the potential association between multimorbidity and the handgrip strength of middle-aged and older adults.

Methods: The baseline (2011) and second-round follow-up (2015) data of China Health and Retirement Longitudinal Study (CHARLS) were used. Adults≥40 were selected as the subjects of the study.

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Objective: To understand the level of job satisfaction and work engagement of physicians in public hospitals, to analyze the interaction between job satisfaction and work engagement, and to discuss how each dimension of job satisfaction affects work engagement so as to provide information and reference for improving the level of work engagement of physicians in public hospitals.

Methods: Covering 6 public hospitals in Sichuan (3 tertiary-level hospitals and 3 secondary-level hospitals), 638 questionnaires were obtained from physicians through convenient sampling for data description and analysis. Pearson correlation method was used to analyze the correlation between job satisfaction and work engagement, and multiple linear stepwise regression method was used to analyze work engagement and the influencing factors of each dimension.

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A copper-catalyzed enantioconvergent Suzuki-Miyaura C(sp)-C(sp) cross-coupling of various racemic alkyl halides with organoboronate esters has been established in high enantioselectivity. Critical to the success is the use of a chiral cinchona alkaloid-derived N,N,P-ligand for not only enhancing the reducing capability of copper catalyst to favor a stereoablative radical pathway over a stereospecific S2-type process but also providing an ideal chiral environment to achieve the challenging enantiocontrol over the highly reactive radical species. The reaction has a broad scope with respect to both coupling partners, covering aryl- and heteroarylboronate esters, as well as benzyl-, heterobenzyl-, and propargyl bromides and chlorides with good functional group compatibility.

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In contrast to the wealth of asymmetric transformations for generating central chirality from alkyl radicals, the enantiocontrol over the allenyl radicals for forging axial chirality represents an uncharted domain. The challenge arises from the unique elongated linear configuration of the allenyl radicals that necessitates the stereo-differentiation of remote motifs away from the radical reaction site. We herein describe a copper-catalyzed asymmetric radical 1,4-carboalkynylation of 1,3-enynes via the coupling of allenyl radicals with terminal alkynes, providing diverse synthetically challenging tetrasubstituted chiral allenes.

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The exact mechanisms associated with secondary brain damage following traumatic brain injury (TBI) remain unclear; therefore, identifying the critical molecular mechanisms involved in TBI is essential. The mRNA expression microarray GSE2871 was downloaded from the Gene Expression Omnibus (GEO) repository. GSE2871 comprises a total of 31 cerebral cortex samples, including two post-TBI time points.

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We describe a photoinduced copper-catalyzed asymmetric radical decarboxylative alkynylation of bench-stable N-hydroxyphthalimide(NHP)-type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp )-C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo- and cross-coupling catalyst but also tuning of the NHP-type esters to inhibit the facile homodimerization of the alkyl radical and terminal alkyne, respectively. Owing to the use of stable and easily available NHP-type esters, the reaction features a broader substrate scope compared with reactions using the alkyl halide counterparts, covering (hetero)benzyl-, allyl-, and aminocarbonyl-substituted carboxylic acid derivatives, and (hetero)aryl and alkyl as well as silyl alkynes, thus providing a vital complementary approach to the previously reported method.

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A copper-catalyzed intermolecular three-component asymmetric radical 1,2-carboalkynylation of alkenes has been developed, providing straightforward access to diverse chiral alkynes from readily available alkyl halides and terminal alkynes. The utilization of a cinchona alkaloid-derived multidentate N,N,P-ligand is crucial for the efficient radical generation from mildly oxidative precursors by copper and the effective inhibition of the undesired Glaser coupling side reaction. The substrate scope is broad, covering (hetero)aryl-, alkynyl-, and aminocarbonyl-substituted alkenes, (hetero)aryl and alkyl as well as silyl alkynes, and tertiary to primary alkyl radical precursors with excellent functional group compatibility.

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Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. Because the molecular mechanisms of DKD are not fully understood, exploration of hub genes and the mechanisms underlying this disease are essential for elucidating the pathogenesis and progression of DKD. Accordingly, in this study, we performed an analysis of gene expression in DKD.

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Transition metal-catalyzed enantioselective Sonogashira-type oxidative C(sp)-C(sp) coupling of unactivated C(sp)-H bonds with terminal alkynes has remained a prominent challenge. The difficulties mainly stem from the regiocontrol in unactivated C(sp)-H bond functionalization and the inhibition of readily occurring Glaser homocoupling of terminal alkynes. Here, we report a copper/chiral cinchona alkaloid-based N,N,P-ligand catalyst for asymmetric oxidative cross-coupling of unactivated C(sp)-H bonds with terminal alkynes in a highly regio-, chemo-, and enantioselective manner.

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Continued development of the Sonogashira coupling has made it a well established and versatile reaction for the straightforward formation of C-C bonds, forging the carbon skeletons of broadly useful functionalized molecules. However, asymmetric Sonogashira coupling, particularly for C(sp)-C(sp) bond formation, has remained largely unexplored. Here we demonstrate a general stereoconvergent Sonogashira C(sp)-C(sp) cross-coupling of a broad range of terminal alkynes and racemic alkyl halides (>120 examples) that are enabled by copper-catalysed radical-involved alkynylation using a chiral cinchona alkaloid-based P,N-ligand.

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A copper-catalyzed asymmetric radical oxytrifluoromethylation of alkenyl oxime and Togni's reagent has been successfully developed, thereby providing straightforward access to CF -containing isoxazolines bearing α-tertiary stereocenters with excellent yield and enantioselectivity. The key to success is the rational design of cinchona-alkaloid-based sulfonamides as neutral/anionic hybrid ligands to effectively control the stereochemistry in copper-catalyzed reactions involving free alkyl radical species. The utility of this method is illustrated by efficient transformation of the products into useful chiral CF -containing 1,3-aminoalcohols.

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Orexins, produced in the lateral hypothalamus, are important neuropeptides that participate in the sleep/wake cycle, and their expression coincides with the projection area of the vagus nerve in the brain. Vagus nerve stimulation has been shown to decrease the amounts of daytime sleep and rapid eye movement in epilepsy patients with traumatic brain injury. In the present study, we investigated whether vagus nerve stimulation promotes wakefulness and affects orexin expression.

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Article Synopsis
  • A new strategy using achiral pyridine as a ligand has been developed to stabilize high-valent copper species for asymmetric radical oxytrifluoromethylation of alkenes.
  • The process operates under mild conditions and accommodates a wide variety of substrates, resulting in trifluoromethyl-substituted tetrahydrofurans with high enantioselectivity.
  • Mechanistic studies indicate that the achiral pyridine plays a crucial role in stabilizing key reactive species during the reaction.
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Although great success has been achieved in asymmetric fluoroalkylation reactions via nucleophilic or electrophilic processes, the development of asymmetric radical versions of this type of reactions remains a formidable challenge because of the involvement of highly reactive radical species. Here we report a catalytic asymmetric radical aminoperfluoroalkylation and aminodifluoromethylation of alkenes with commercially available fluoroalkylsulfonyl chlorides as the radical sources, providing a versatile platform to access four types of enantioenriched α-tertiary pyrrolidines bearing β-perfluorobutanyl, trifluoromethyl, difluoroacetyl and even difluoromethyl groups in excellent yields and with excellent enantioselectivity. The key to success is not only the introduction of the CuBr/chiral phosphoric acid dual-catalytic system but also the use of silver carbonate to suppress strong background and side hydroamination reactions caused by a stoichiometric amount of the in situ generated HCl.

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A novel asymmetric radical aminotrifluoromethylation of alkenes has been developed for the first time, providing straightforward access to densely functionalized CF3-containing azaheterocycles bearing an α-tertiary stereocenter with excellent enantioselectivity. The key to success is not only the introduction of a Cu(I)/chiral phosphoric acid dual-catalytic system but also the use of urea with two acidic N-H as both the nucleophile and directing group. The utility of this method is illustrated by facile transformations of the products into other important compounds useful in organic synthesis and medicinal chemistry.

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