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1.
J Microbiol ; 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424579

RESUMO

Endophytes colonize tissues of healthy host plants and play a crucial role in plant growth and development. However, little attention has been paid to the endophytes of tuber crops such as cassava, which is used as a staple food by approximately 800 million people worldwide. This study aimed to elucidate the diversity and composition of endophytic bacterial and fungal communities in different cassava cultivars using high-throughput sequencing. Although no significant differences in richness or diversity were observed among the different cassava cultivars, the community compositions were diverse. Two cultivars (SC124 and SC205) tolerant to root rot exhibited similar community compositions, while two other cultivars (SC10 and SC5), which are moderately and highly susceptible to root rot, respectively, harboured similar community compositions. Proteobacteria, Firmicutes, and Ascomycota dominated the endophyte assemblages, with Weissella, Serratia, Lasiodiplodia, Fusarium, and Diaporthe being the predominant genera. The differentially abundant taxonomic clades between the tolerant and susceptible cultivars were mainly rare taxa, such as Lachnoclostridium_5, Rhizobium, Lampropedia, and Stenotrophomonas. These seemed to be key genera that affected the susceptibility of cassava to root rot. Moreover, the comparison of KEGG functional profiles revealed that 'Environmental adaptation' category was significantly enriched in the tolerant cultivars, while 'Infectious diseases: Parasitic' category was significantly enriched in the susceptible cultivars. The present findings open opportunities for further studies on the roles of endophytes in the susceptibility of plants to diseases.

2.
Nat Struct Mol Biol ; 27(5): 472-479, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32398826

RESUMO

Cryptochromes (CRYs) are blue-light receptors in plants that harbor FAD as a cofactor and regulate various physiological responses. Photoactivated CRYs undergo oligomerization, which increases the binding affinity to downstream signaling partners. Despite decades of research on the activation of CRYs, little is known about how they are inactivated. Binding of blue-light inhibitors of cryptochromes (BICs) to CRY2 suppresses its photoactivation, but the underlying mechanism remains unknown. Here, we report crystal structures of CRY2N (CRY2 PHR domain) and the BIC2-CRY2N complex with resolutions of 2.7 and 2.5 Å, respectively. In the BIC2-CRY2N complex, BIC2 exhibits an extremely extended structure that sinuously winds around CRY2N. In this way, BIC2 not only restrains the transfer of electrons and protons from CRY2 to FAD during photoreduction but also interacts with the CRY2 oligomer to return it to the monomer form. Uncovering the mechanism of CRY2 inactivation lays a solid foundation for the investigation of cryptochrome protein function.

3.
Microb Pathog ; 145: 104226, 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32353577

RESUMO

Transfer-messenger RNA (tmRNA) is ubiquitous in bacteria, acting as the core component for the trans-translation system that contributes to label the aberrantly synthesized peptides for degradation and to release the stalled ribosomes. Deletion of tmRNA causes a variety of phenotypes related to important physiological processes in bacteria. To illustrate the molecular mechanism of the versatility of tmRNA in aquatic pathogen Aeromonas veronii, we mutated the C-terminal nucleotides of tmRNA (MutmRNA) for encoding a tag containing six histidine residues (His6tag), so as to capture and enrich the trans-translation substrates from the cell lysates through a Ni2+-NTA affinity chromatograph. The results showed that the concentrated substrates were detected as distinct and specific bands in western blotting using anti-His antibody, demonstrating that specific defective mRNAs were frequently and intensively rescued by trans-translation during the translation process in A. veronii. The substrates were analyzed by LC-MS/MS and further identified by searching a theoretically constructed database specific for A. veronii. Total of 24 potential substrates were identified, with various functions involved in metabolism, as well as structure and signal-based cellular events. Among the identified substrates, PspA and AsmA were labeled by Flag, and expressed in the presence of the modified trans-translation system in E. coli. Their labelings with MutmRNA were validated by purification through Ni2+-NTA column followed by western blotting using anti-Flag antibody. This study provided the most abundant set of endogenous targets for tmRNA in A. veronii, and facilitated further investigations about the molecular mechanism and signal pathway of tmRNA-mediated trans-translation.

4.
Biosci Rep ; 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32426838

RESUMO

LncRNA LINC00657 has oncogenic or anti-carcinoma roles in different cancers, and yet its detailed molecular mechanism in esophageal cancer(EC) remains unclear. In addition, competitive endogenous RNA (ceRNA) regulatory lncRNA-miRNA-mRNA networks are critical for tumorigenesis and progression. Hence, this study explored the roles of LINC00657 in EC and identified its relevant ceRNA network. We firstly detected the expression of LINC00657 in EC. Then, we applied starBase and TargetScan websites to find miR-26a-5p binding to LINC00657 and obtain CKS2 as a target of miR-26a-5p. The roles of LINC00657, miR-26a-5p or CKS2 in the proliferation, migration, invasion and apoptosis of EC cells were respectively assessed by CCK-8, wound healing assay, transwell invasion assay, and flow cytometry. The changes of the MDM2/p53/Bcl2/Bax pathway were measured via western blot. The results revealed that LINC00657 showed an aberrant high expression in EC cells, which promoted the growth of EC cells. Additionally, LINC00657 functioned as a sponge of miR-26a-5p, and LINC00657 negatively mediated miR-26a-5p to regulate the growth of EC cells. Furthermore, CKS2 was observed as a direct target of miR-26a-5p, and CKS2 controlled the growth of EC cells via the MDM2/p53/Bcl2/Bax pathway. Moreover, there was a positive correlation between LINC00657 and CKS2. LINC00657 knockdown inhibited CKS2 expression to suppress the proliferation, migration and invasion of EC cells and induced apoptosis via regulating the MDM2/p53/Bcl2/Bax pathway. Collectively, LINC00657/miR-26a-5p/CKS2 ceRNA network could promote the progression of EC, which is good for understanding the molecular mechanism of EC and offers novel biomarkers for EC diagnosis and therapy.

5.
Nanotechnology ; 31(24): 245601, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32249760

RESUMO

Although homogeneous, high quality graphene can be fabricated on a Cu or Ni sheet using the traditional chemical vapour deposition method at high temperatures (over 1000 °C) under specific atmospheric conditions, their transfer to another substrate is difficult. In this paper a novel method of rapidly (i.e. 3-6 s of laser irradiation) producing a large area (>3 cm2) graphene film from olive oil on a glass surface (pre-coated with a 5-28 nm thick Ni film) with defocused, large area continuous laser irradiation is described. The turbostratic graphene film (6 layers) grown in such a way has shown high electrical conductivity (sheet resistance of around 20 Ω sq-1) and an optical transmittance of 40-50%. With femtosecond laser patterning, 70% optical transparency was demonstrated. Continuous large area graphene was formed at relatively lower temperatures (<250 °C) and without the need for specific atmospheric conditions. The basic process characteristics and mechanisms involved are discussed.

6.
BMC Neurol ; 20(1): 154, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32334559

RESUMO

BACKGROUND: Dysphagia is common after stroke. Patients with dysphagia have a higher risk of stroke-associated pneumonia (SAP) and poor outcomes. Early detection of dysphagia is necessary to identify and manage patients at high risk of aspiration. The aim of the study was to assess the impact of the systematic administration of the volume-viscosity swallow test (V-VST) in patients with acute ischaemic stroke. METHODS: This was a retrospective observational study that enrolled patients with acute ischaemic stroke in two consecutive time periods: pre-V-VST, when the 30-mL water-swallowing test (WST) was systematically administered, and V-VST, when all patients underwent the WST and the V-VST test was systematically administered if the patient failed the WST. RESULTS: Two hundred and 42 patients were enrolled. The mean age of the participants was 68.8 ± 10.88 years, 61.2% were male, and the median National Institutes of Health Stroke Scale score was 3 (IQR, 1-6). A total of 147 patients were enrolled during the pre-V-VST period and 95 were enrolled during the V-VST period. There was a significant difference in the occurrence of SAP (21.8% vs. 10.5%, p = 0.024) and the rate of nasogastric tube feeding (25.9% vs. 14.7%, p = 0.040) between the two groups, and no differences were found in the length of hospital stay (p = 0.277) or the total cost of hospitalization (p = 0.846). CONCLUSIONS: The V-VST was a better clinical screening tool, and it can also provide detailed suggestions regarding dietary modifications to prevent aspiration and SAP.

7.
Artigo em Inglês | MEDLINE | ID: mdl-32215944

RESUMO

Pseudogenes, another novel group of non-coding segments without protein-coding capacity, are closely associated with tumourigenesis and cancer progression. Double homeoboxA pseudogene 10 (DUXAP10) is reported to be robustly expressed in thyroid carcinoma. However, the functional role and underlying mechanism of DUXAP10 in papillary thyroid carcinoma (PTC) progression remain undefined. DUXAP10 expression in PTC cells was detected by qRT-PCR. Cell proliferation and invasion were determined using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and Transwell invasion assay, respectively. Apoptosis was evaluated using flow cytometry. Protein expression of matrix metalloproteinase (MMP)-2, MMP-9, protein kinase B (Akt), phosphorylated Akt, mammalian target of rapamycin (mTOR), and phosphorylated mTOR was examined by western blot. Results showed that DUXAP10 was significantly overexpressed in PTC cells compared with normal thyroid follicular epithelium cells. DUXAP10 silencing suppressed cell proliferation and invasive ability, reduced the expression of MMP-2 and MMP-9, and increased apoptotic rate and caspase-3 activity in PTC cells. Additionally, the Akt/mTOR pathway was inhibited following DUXAP10 knockdown in PTC cells. Activation of the Akt/mTOR pathway by 740Y-P and MHY1485 attenuated DUXAP10 knockdown-induced proliferation reduction, invasion suppression and apoptosis in PTC cells. In conclusion, DUXAP10 knockdown suppressed proliferation and invasion and induced apoptosis in PTC cells at least partially by inhibition of the Akt/mTOR pathway.

8.
J Adv Nurs ; 76(6): 1384-1393, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32128865

RESUMO

AIMS: To test prospective pathways of a Comprehensive Reminder System based on the Health Belief Model (CRS-HBM), stroke knowledge, health belief in health behaviour, blood pressure (BP) control, and disability in hypertensive ischaemic stroke patients at 6-month postdischarge. DESIGN: A nested cohort study design. METHODS: Data were derived from a randomized controlled trial evaluating the effects of the intervention (N = 174, performed during February 2015 - March 2016). Data were collected by questionnaires and analysed in structural equation modelling in Mplus software. RESULTS: The proposed model provided a good fit to the data. This model accounted for 51.5% of the variance in health behaviour, 34.1% in BP control, and 5.7% in modified Rankin Scale score at 6-month postdischarge. The CRS-HBM had: (a) direct positive effect (ß = .391, p < .001) and indirect positive effects (ß = .186, p = .002) on health behaviour; (b) direct positive effect (ß = .356, p < .001) and indirect positive effects (ß = .183, p = .009) on BP control; and (c) indirect negative effect (ß = -.146, p = .008) on disability. Being female was linked to better health behaviour. Higher education predicted higher level of stroke knowledge and health belief. CONCLUSIONS: The CRS-HBM can not only directly but also indirectly improve patients' health behaviours by improving their health knowledge or health belief. Better health behaviour can improve patients' BP control and reduce disability. Therefore, nurses need to pay more attention to not only patients' health knowledge but also their health belief when providing education. IMPACT: The CRS-HBM intervention accounted for 51.5% of variance in health behaviour, 34.1% in BP control, and 5.7% in modified Rankin Scale score at 6-month postdischarge. This research can help nurses improve health education strategies in postdischarge and community contexts to achieve better health results.

9.
Artigo em Inglês | MEDLINE | ID: mdl-32185140

RESUMO

Bacterial persisters are a small proportion of phenotypically heterogeneous variants with the transient capability to survive in high concentrations of antibiotics, causing recurrent infections in both human and aquatic animals. Transfer-messenger RNA (tmRNA), which was encoded by the ssrA gene, was identified as a determinant regulator mediating the persistence to ß-lactams in the pathogenic Aeromonas veronii C4. The deletion of tmRNA exhibited the increased ability of persister formation most probably due to the reduction of protein synthesis. Transcriptomic and metabolomic analyses revealed that the absence of tmRNA not only significantly elevated the intercellular levels of metabolite GlcNAc and promoted NaCl osmotic tolerance, but also upregulated the expression of metabolic genes in both the upstream biosynthesis pathway and the downstream metabolic flux of peptidoglycan (PG) biosynthesis. Finally, exogenous GlcNAc stimulated significant bacterial growth, enhanced content of GlcNAc in the cell wall, higher resistance to osmotic response, and higher persistence to cefotaxime in a concentration-dependent manner, implying its potential role in promoting the multiple phenotypes observed in tmRNA deletion strains. Taken together, these results hint at a potential mechanism of persister formation mediated by tmRNA against the ß-lactam challenges in A. veronii.

10.
Org Lett ; 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32119556

RESUMO

Asymmetric annulation of bench-stable α,ß-unsaturated aryl esters with enamines was realized via cooperative catalysis of chiral isothiourea and Brønsted acid. This reaction proceeds via a chiral α,ß-unsaturated acyl ammonium intermediate and offers a rapid access to functionalized 3,4-dihydropyridin-2-ones in high yields and excellent enantioselectivities.

11.
J Cell Physiol ; 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32100885

RESUMO

Successful use of oocytes from small follicles (SFs) is of great importance for animal embryo production and human in vitro fertilization with reduced hormone-related side effects. How in vitro meiotic arrest maintenance (MAM) increases the competence of oocytes is not clear. In this study, pig oocytes recovered from SF of 1-2 mm and medium-follicles (MF) of 3-6 mm in diameter from abattoir ovaries were treated by various MAM treatments to improve their competence. The results showed that 25 µM roscovitine or 1 mM db-cAMP efficiently blocked germinal vesicle breakdown in both SF and MF oocytes suggesting a similar cyclin-dependent kinase (CDK) 1 level between the two oocyte groups. MAM with 15- and 25-µM roscovitine alone or with 1-mM db-cAMP improved competence of SF and MF oocytes, respectively, with a promoted chromatin configuration transition from surrounded nucleoli (SN) to re-decondensation (RDC) pattern that supported substantial gene transcription. However, MAM with db-cAMP alone or with higher concentrations of roscovitine did not improve oocyte competence, could not support an SN-to-RDC transition, and/or evoked a premature chromatin condensation (PMC) that suppressed gene transcription. Both CDK2 and CDK5 contents were higher (p < .05) in MF than in SF oocytes. It is concluded that the competence of pig oocytes, particularly that of SF oocytes can be improved by MAM using a proper roscovitine concentration that promotes gene transcription by inhibiting CDK5 while letting CDK2 off to prevent PMC.

12.
BMC Evol Biol ; 20(1): 29, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32059644

RESUMO

BACKGROUND: Crocidura, the most speciose mammalian genus, occurs across much of Asia, Europe and Africa. The taxonomy of Chinese representatives has been studied primarily based on cursory morphological comparisons and their molecular phylogenetic analyses remain unexplored. In order to understand the phylogeny of this group in China, we estimated the first multilocus phylogeny and conducted species delimitation, including taxon sampling throughout their distribution range. RESULTS: We obtained one mitochondrial gene (cytb) (~ 1, 134 bp) and three nuclear genes (ApoB, BRCA1, RAG1) (~ 2, 170 bp) for 132 samples from 57 localities. Molecular analyses identified at least 14 putative species that occur within two major well-supported groups in China. Polyphyletic C. wuchihensis appears to be composed of two putative species. Two subspecies, C. rapax rapax and C. rapax kurodai should be elevated to full species status. A phylogenetic tree based on mitochondrial gene from Asian Crocidura species showed that the C. rapax rapax is embedded within C. attenuata, making the latter a paraphyletic group. Three strongly supported undescribed species (C. sp.1, C. sp.2 and C. sp.3) are revealed from Zada County of Tibet (Western China), Hongjiang County of Hunan Province (Central China) and Dongyang County of Zhejiang Province (Eastern China), Motuo County of Tibet, respectively. The divergence time estimation suggested that China's Crocidura species began to diversify during the late Pliocene (3.66 Ma) and the Early Pleistocene (2.29 Ma), followed by a series of diversifications through the Pleistocene. CONCLUSIONS: The cryptic diversity found in this study indicated that the number of species is strongly underestimated under the current taxonomy. We propose that the three undescribed species should be evaluated using extensive taxon sampling and comprehensive morphological and morphometric approaches. Climate change since the late Pliocene and the uplift of the Qinghai-Tibet Plateau may result in the diversification and speciation of China's Crocidura species. In short, the underestimated diversity underlines the need for a taxonomic revision of Chinese Crocidura species.

13.
Insect Sci ; 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31944573

RESUMO

Intrasexual selection occurs in male-male competition over access to females and usually results in the larger male winning. While much research has documented that size matters, little is known about how the larger male wins. Dendroctonus valens is an aggregating monogamous bark beetle in which males have large variation in body size and display intense competition over females. Behavioral observation showed two males fight each other within the gallery by pushing/shoving and stridulated more when two males encountered each other. Experiments using two different-sized males synchronously competing showed that larger males won 95% of contests. Reciprocal displacement experiments using muted and intact males of different or equal size were used to simulate male-male competition. Larger males displaced the smaller resident male in 90% of contests, while smaller males prevailed over larger residents in 6.7% of contests. With both males silenced, larger males displaced smaller males in 80% of contests, while smaller males prevailed in 8% of contests. Further experiments using equal-sized males showed aggressive sound-emitting males displaced muted males in 67% of contests, yet intact males displaced other intact males in only 37.5% of contests. Sound analysis showed sound pressure level is an honest signal of body size and males chose soft sounds over loud aggressive sounds in assays. Therefore, D. valens males have evolved dual behaviors, fighting and aggressive sounds associated with body size, to assess rivals to compete for a partner, gaining insights in male-male competition for this species and for other animals.

14.
Nat Commun ; 11(1): 182, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924775

RESUMO

Urban activities have profound and lasting effects on the global carbon balance. Here we develop a consistent metabolic approach that combines two complementary carbon accounts, the physical carbon balance and the fossil fuel-derived gaseous carbon footprint, to track carbon coming into, being added to urban stocks, and eventually leaving the city. We find that over 88% of the physical carbon in 16 global cities is imported from outside their urban boundaries, and this outsourcing of carbon is notably amplified by virtual emissions from upstream activities that contribute 33-68% to their total carbon inflows. While 13-33% of the carbon appropriated by cities is immediately combusted and released as CO2, between 8 and 24% is stored in durable household goods or becomes part of other urban stocks. Inventorying carbon consumed and stored for urban metabolism should be given more credit for the role it can play in stabilizing future global climate.

15.
Org Biomol Chem ; 18(1): 135-139, 2019 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-31803894

RESUMO

We developed a facile synthetic method to access cyclopenta[b]naphthalene derivatives via the Lewis or Brønsted acid catalysed cascade nucleophilic addition, electronic cyclization, ring-opening rearrangement of propargylic alcohol-tethered alkylidenecyclopropanes with indole and pyrrole derivatives. The reaction exhibited a broad substrate scope and good functional group tolerance under metal-free conditions, affording the desired products in moderate to good yields.

16.
Nat Commun ; 10(1): 5558, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31804470

RESUMO

The global urbanization rate is accelerating; however, data limitations have far prevented robust estimations of either global urban expansion or its effects on terrestrial net primary productivity (NPP). Here, using a high resolution dataset of global land use/cover (GlobeLand30), we show that global urban areas expanded by an average of 5694 km2 per year between 2000 and 2010. The rapid urban expansion in the past decade has in turn reduced global terrestrial NPP, with a net loss of 22.4 Tg Carbon per year (Tg C year-1). Although small compared to total terrestrial NPP and fossil fuel carbon emissions worldwide, the urbanization-induced decrease in NPP offset 30% of the climate-driven increase (73.6 Tg C year-1) over the same period. Our findings highlight the urgent need for global strategies to address urban expansion, enhance natural carbon sinks, and increase agricultural productivity.

17.
Top Curr Chem (Cham) ; 378(1): 9, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31879793

RESUMO

Asymmetric metal/organo relay catalysis, utilizing a metal complex and a chiral organocatalyst in a one-pot cascade reaction, is aimed to sequentially impart activation on multiple steps by distinct catalysts. Such a catalysis merges the advantages of both metal catalysis and organocatalysis, providing step-economy, and, more importantly, the potential to achieve inaccessible reactivity by a single catalyst. Chiral phosphoric acids are among the most robust organocatalysts, rendering a broad range of enantioselective bond-forming reactions. The combination of metal complexes and chiral phosphoric acids in a single vessel has been well documented. In particular, the asymmetric relay catalysis of metal complex with chiral phosphoric acid has grown rapidly since 2008. Several excellent reviews have been published to cover almost all examples in this area from 2008 to early 2014; therefore, in this chapter, we will mainly highlight progress from 2014 to mid-2019.


Assuntos
Complexos de Coordenação/química , Ácidos Fosfóricos/química , Catálise , Estrutura Molecular , Estereoisomerismo
18.
Artigo em Inglês | MEDLINE | ID: mdl-31751198

RESUMO

A Gram-stain-positive, moderately halophilic, strictly aerobic, endospore-forming, rod-shaped bacterium, strain JSM 102062T, was isolated from a non-saline farm soil sample collected from Dehang Canyon in Hunan, PR China. Growth occurred with 0.5-20 % (w/v) NaCl (optimum 4-7 %) at pH 5.5-11.0 (optimum pH 8.0) and at 20-50 °C (optimum 30-35 °C). Contained cell-wall peptidoglycan based on meso-diaminopimelic acid and possessed menaquinone-7 (MK-7) as the major respiratory isoprenoid quinone. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, five unidentified phospholipids and an unidentified glycolipid. The DNA G+C content was 44.1 mol%. Phylogeny based on 16S rRNA gene sequences indicated that strain JSM 102062T belonged to the genus Sediminibacillus, sharing high 16S rRNA gene sequence similarities to Sediminibacillus halophilus EN8dT (99.4 %) and Sediminibacillus albus NHBX5T (98.3 %). The whole genomic analysis showed that strain JSM 102062T constituted a different taxon separated from the recognized Sediminibacillus species. Combined data from phenotypic and genotypic studies demonstrated that strain JSM 102062T represents a noval species of the genus Sediminibacillus, for which the name Sediminibacillus terrae sp. nov. is proposed; the type strain is JSM 102062T (=CCTCC AB 2014166T = CGMCC 1.12957T=DSM 28949T=KCTC 33541T).

19.
Nat Commun ; 10(1): 4337, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31554811

RESUMO

Substantial quantities of air pollution and related health impacts are ultimately attributable to household consumption. However, how consumption pattern affects air pollution impacts remains unclear. Here we show, of the 1.08 (0.74-1.42) million premature deaths due to anthropogenic PM2.5 exposure in China in 2012, 20% are related to household direct emissions through fuel use and 24% are related to household indirect emissions embodied in consumption of goods and services. Income is strongly associated with air pollution-related deaths for urban residents in which health impacts are dominated by indirect emissions. Despite a larger and wealthier urban population, the number of deaths related to rural consumption is higher than that related to urban consumption, largely due to direct emissions from solid fuel combustion in rural China. Our results provide quantitative insight to consumption-based accounting of air pollution and related deaths and may inform more effective and equitable clean air policies in China.


Assuntos
Poluição do Ar/análise , Exposição Ambiental/estatística & dados numéricos , Mortalidade Prematura/tendências , Saúde da População Rural/estatística & dados numéricos , Fatores Socioeconômicos , Saúde da População Urbana/estatística & dados numéricos , Poluição do Ar/efeitos adversos , Grupo com Ancestrais do Continente Asiático/estatística & dados numéricos , China , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Política Ambiental/legislação & jurisprudência , Política Ambiental/tendências , Características da Família , Humanos , Mortalidade Prematura/etnologia , Material Particulado/análise
20.
Angew Chem Int Ed Engl ; 58(47): 16806-16810, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31475764

RESUMO

Branched selectivity in asymmetric allylic C-H alkylation is enabled by using 2-acylimidazoles as nucleophiles in the presence of a chiral phosphoramidite-palladium catalyst. A wide range of terminal alkenes, including 1,4-dienes and allylarenes, are nicely tolerated and provide chiral 2-acylimidazoles in moderate to high yields and with high levels of regio-, and enantio-, and E/Z-selectivities. Mechanistic studies using density-functional theory calculations suggest a nucleophile-coordination-enabled inner-sphere attack mode for the enantioselective carbon-carbon bond-forming event.

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