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1.
Proc Natl Acad Sci U S A ; 118(39)2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34544859

RESUMO

Electrophilic aromatic substitution (EAS) reactions are widely regarded as characteristic reactions of aromatic species, but no comparable reaction has been reported for molecules with Craig-Möbius aromaticity. Here, we demonstrate successful EAS reactions of Craig-Möbius aromatics, osmapentalenes, and fused osmapentalenes. The highly reactive nature of osmapentalene makes it susceptible to electrophilic attack by halogens, thus osmapentalene, osmafuran-fused osmapentalene, and osmabenzene-fused osmapentalene can undergo typical EAS reactions. In addition, the selective formation of a series of halogen substituted metalla-aromatics via EAS reactions has revealed an unprecedented approach to otherwise elusive compounds such as the unsaturated cyclic chlorirenium ions. Density functional theory calculations were conducted to study the electronic effect on the regioselectivity of the EAS reactions.

2.
Chem Commun (Camb) ; 57(68): 8464-8467, 2021 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-34346430

RESUMO

The reactivity of the triflate functionalized iridapentalene 1, [Ir{[double bond, length as m-dash]CHC(CH2C(CO2Me)2CH2)[double bond, length as m-dash]CC[double bond, length as m-dash]CHC(OTf)[double bond, length as m-dash]CH}(CO)(PPh3)2]OTf, with C-, N-, O- and S-centered neutral nucleophiles was studied, leading to the isolation of a wide array of irida-carbolong derivatives. As an extension, a polycyclic complex with a rare six-fused-ring structure was constructed. This strategy provides a new route for the construction of functionalized metallaaromatic complexes, and the resulting iridacycles exhibit broad spectral absorption ranges, making them potential photoelectric materials.

3.
Biomed Res Int ; 2021: 8410317, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33997042

RESUMO

Objective: (1) To propose a novel technique named thoracic extensive laminoplasty (TELP) in curing severe thoracic ligamentum flavum ossification (STOLF) and (2) to compare outcomes between TELP and laminectomy in curing STOLF. Methods: Cases with fused or tuberous STOLF (Sato classification) treated from Jan 2015 to Jan 2017 were reviewed and divided into the TELP group (G1) and laminectomy group (G2) according to their surgical management. Data on demographics, complications, pre- and postoperative symptoms, residual spinal canal area (RSCA-1), residual spinal cord area (RSCA-2), modified Japanese Orthopedic Association score (mJOA), and health-related quality of life (HRQOL, based on the SF-36) were collected. Results: Fifty-nine G1 and sixty-two G2 patients were enrolled. No significant differences in demographic data or preoperative data of RSCA-1, RSCA-2, mJOA, or HRQOL were observed between the two groups (p > 0.05). Patients in G1 and G2 showed similar postoperative improvements in RSCA-1 and RSCA-2 at the final follow-up (p > 0.05). However, patients in G1 showed higher postoperative improvements in mJOA (OR = 2.706, 95% CI: 1.279~5.727, p = 0.008) at the final follow-up. Patients in G1 also showed higher postoperative improvements in HRQOL than patients in G2 (p < 0.05) at the final follow-up, and patients with more severe STOLF presented with better improvements in HRQOL in G1 (p < 0.05). Dural laceration and cerebrospinal fluid leakage were observed in seven G2 patients, and no complications were found in G1 patients after surgery. Conclusion: TELP is a novel, effective, and safer surgical technique in treating STOLF and could be a substitute for traditional laminectomy.


Assuntos
Laminectomia , Laminoplastia , Ligamento Amarelo/cirurgia , Ossificação do Ligamento Longitudinal Posterior/cirurgia , Doenças da Coluna Vertebral/cirurgia , Estudos de Casos e Controles , Feminino , Humanos , Laminectomia/efeitos adversos , Laminectomia/métodos , Laminoplastia/efeitos adversos , Laminoplastia/métodos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Qualidade de Vida
4.
Front Plant Sci ; 11: 571864, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33193507

RESUMO

The salinization and alkalization of soil are widespread environmental problems. Sugar beet (B. vulgaris L.) is a moderately salt tolerant glycophyte, but little is known about the different mechanisms of sugar beet response to salt and alkaline stresses. The aim of this study was to investigate the influence of neutral salt (NaCl:Na2SO4, 1:1) and alkaline salt (Na2CO3) treatment on physiological and transcriptome changes in sugar beet. We found that a low level of neutral salt (NaCl:Na2SO4; 1:1, Na+ 25 mM) or alkaline salt (Na2CO3, Na+ 25 mM) significantly enhanced total biomass, leaf area and photosynthesis indictors in sugar beet. Under a high concentration of alkaline salt (Na2CO3, Na+ 100 mM), the growth of plants was not significantly affected compared with the control. But a high level of neutral salt (NaCl: Na2SO4; 1:1, Na+ 100 mM) significantly inhibited plant growth and photosynthesis. Furthermore, sugar beet tends to synthesize higher levels of soluble sugar and reducing sugar to cope with high neutral salt stress, and more drastic changes in indole acetic acid (IAA) and abscisic acid (ABA) contents were detected. We used next-generation RNA-Seq technique to analyze transcriptional changes under neutral salt and alkaline salt treatment in sugar beet. Overall, 4,773 and 2,251 differentially expressed genes (DEGs) were identified in leaves and roots, respectively. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that genes involving cutin, suberine and wax biosynthesis, sesquiterpenoid and triterpenoid biosynthesis and flavonoid biosynthesis had simultaneously changed expression under low neutral salt or alkaline salt, so these genes may be related to stimulating sugar beet growth in both low salt treatments. Genes enriched in monoterpenoid biosynthesis, amino acids metabolism and starch and sucrose metabolism were specifically regulated to respond to the high alkaline salt. Meanwhile, compared with high alkaline salt, high neutral salt induced the expression change of genes involved in DNA replication, and decreased the expression of genes participating in cutin, suberine and wax biosynthesis, and linoleic acid metabolism. These results indicate the presence of different mechanisms responsible for sugar beet responses to neutral salt and alkaline salt stresses.

5.
Microorganisms ; 8(3)2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32150839

RESUMO

Fusarium asiaticum belongs to one of the phylogenetical subgroups of the F. graminearum species complex and is epidemically predominant in the East Asia area. The life cycle of F. asiaticum is significantly regulated by light. In this study, the fungal blue light receptor white collar complex (WCC), including FaWC1 and FaWC2, were characterized in F. asiaticum. The knockout mutants ΔFawc1 and ΔFawc2 were generated by replacing the target genes via homologous recombination events. The two mutants showed similar defects in light-induced carotenoid biosynthesis, UV-C resistance, sexual fruiting body development, and the expression of the light-responsive marker genes, while in contrast, all these light responses were characteristics in wild-type (WT) and their complementation strains, indicating that FaWC1 and FaWC2 are involved in the light sensing of F. asiaticum. Unexpectedly, however, the functions of Fawc1 and Fawc2 diverged in regulating virulence, as the ΔFawc1 was avirulent to the tested host plant materials, but ΔFawc2 was equivalent to WT in virulence. Moreover, functional analysis of FaWC1 by partial disruption revealed that its light-oxygen-voltage (LOV) domain was required for light sensing but dispensable for virulence, and its Zinc-finger domain was required for virulence expression but not for light signal transduction. Collectively, these results suggest that the conserved fungal blue light receptor WCC not only endows F. asiaticum with light-sensing ability to achieve adaptation to environment, but it also regulates virulence expression by the individual component FaWC1 in a light-independent manner, and the latter function opens a way for investigating the pathogenicity mechanisms of this important crop disease agent.

6.
Sci Adv ; 6(3): eaay2535, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-32010769

RESUMO

The never-ending pursuits for exploring aromatic molecular architectures result in the large libraries of aromatics with fascinating structures, which have greatly broadened the scope of aromaticity. Despite extensive efforts that have been paid to develop aromatic frameworks, the construction of polycyclic aromatics that share a bridgehead atom with more than three rings has never been accomplished. Here, an unprecedented family of aromatics, in which a metal center shared by 4 five-membered aromatic rings, has been achieved by using the metalla-click reactions with excellent yields and remarkable regioselectivity. The distinctive tetracyclic aromatics exhibit a broad absorption in the ultraviolet-visible near-infrared region and excellent thermal stability in air, enabling their potential applications in photoelectric materials and biomedicine. This study now makes it possible to incorporate four aromatic rings with one common sharing metal center by a straightforward strategy that would promote further development of previously unknown polycyclic complex motifs in aromatic chemistry.

7.
Zhongguo Zhong Yao Za Zhi ; 44(9): 1850-1856, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31342712

RESUMO

As known,simultaneous determination of various chemical indicators is one of the future trends in quality control of traditional Chinese medicines because of the extremely complex chemical compositions. This project is to screen the quality markers that can accurately control the quality of the Bufonis Venenum by exploring the intrinsic correlation of components. In this study,venom of Bufo bufo gargarizans from 17 different sources were used as research samples,and the contents of 7 bufogenin were determined by HPLC-DAD. Then,the data obtained were analyzed by Spearman correlation analysis and principal component analysis( PCA). In addition,a stepwise regression analysis was used to establish a predictive model for the contents of the seven bufogenin components( independent variable) and the total contents of the bufogenin( dependent variable). The results indicated that there is a significant positive correlation between the contents of telocinobufagin and cinobufotalin,and there is a significant positive correlation between the contents of bufalin,cinobufagin and resibufogenin. In contrast,the contents of telocinobufagin and cinobufotalin are negatively correlated with the contents of bufalin,cinobufagin and resibufogenin. However,the correlation between gamabufotalin and bufotalin and other components are not obvious. Furthermore,further study found that there is a correlation between the sum of the contents of bufalin,cinobufagin and telocinobufagin and the total contents of the bufogenin. In fact,the application of bufalin,cinobufagin and telocinobufagin as the quality control indicators of the Bufonis Venenum can better reflect the quality characteristics of the Bufonis Venenum compared with the previous quality control indicators. The conclusions will provide a reference for the revision of the quality standards of the Bufonis Venenum.


Assuntos
Venenos de Anfíbios/química , Bufanolídeos/análise , Bufo bufo , Animais , Cromatografia Líquida de Alta Pressão , Medicina Tradicional Chinesa , Controle de Qualidade
8.
ISA Trans ; 93: 218-230, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30987805

RESUMO

The pilot operated directional valves are widely used in hydraulic systems. For the purpose to improve the dynamic characteristics and control accuracy of the traditional valve, this paper proposes a novel pilot valve that employs two independent valve spools instead of the traditional port coupled valve spool. Due to the new structure, the influence of deadzone and damping on the performance of the valve is lightened; the dynamic characteristics and control accuracy of the valve are improved. Both of the open-loop simulation and experimental closed-loop position control of the entire valve demonstrate that the novel valve has impressive performance improvement of the entire valve. The results of experiments show that the -3dB-frequency of novel valve improves 61.5% in the case of single side control mode (SS) and 57.1% in the case of both side control mode (BS); the tracking error decreases from 6.21% to 2.6% in the case of SS and from 7.48% to 3.96% in case of BS.

9.
Proc Natl Acad Sci U S A ; 116(18): 9115-9124, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30996120

RESUMO

Emerging evidence suggests that tissue plasminogen activator (tPA), currently the only FDA-approved medication for ischemic stroke, exerts important biological actions on the CNS besides its well-known thrombolytic effect. In this study, we investigated the role of tPA on primary neurons in culture and on brain recovery and plasticity after ischemic stroke in mice. Treatment with recombinant tPA stimulated axonal growth in culture, an effect independent of its protease activity and achieved through epidermal growth factor receptor (EGFR) signaling. After permanent focal cerebral ischemia, tPA knockout mice developed more severe sensorimotor and cognitive deficits and greater axonal and myelin injury than wild-type mice, suggesting that endogenously expressed tPA promotes long-term neurological recovery after stroke. In tPA knockout mice, intranasal administration of recombinant tPA protein 6 hours poststroke and 7 more times at 2 d intervals mitigated white matter injury, improved axonal conduction, and enhanced neurological recovery. Consistent with the proaxonal growth effects observed in vitro, exogenous tPA delivery increased poststroke axonal sprouting of corticobulbar and corticospinal tracts, which might have contributed to restoration of neurological functions. Notably, recombinant mutant tPA-S478A lacking protease activity (but retaining the EGF-like domain) was as effective as wild-type tPA in rescuing neurological functions in tPA knockout stroke mice. These findings demonstrate that tPA improves long-term functional outcomes in a clinically relevant stroke model, likely by promoting brain plasticity through EGFR signaling. Therefore, treatment with the protease-dead recombinant tPA-S478A holds particular promise as a neurorestorative therapy, as the risk for triggering intracranial hemorrhage is eliminated and tPA-S478A can be delivered intranasally hours after stroke.


Assuntos
Plasticidade Neuronal/efeitos dos fármacos , Acidente Vascular Cerebral/tratamento farmacológico , Ativador de Plasminogênio Tecidual/uso terapêutico , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Encéfalo/metabolismo , Lesões Encefálicas/tratamento farmacológico , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/metabolismo , Infarto Cerebral , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/efeitos dos fármacos , Neurônios/metabolismo , Recuperação de Função Fisiológica
10.
ISA Trans ; 94: 234-245, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30975457

RESUMO

The pilot operated proportional directional valves (POPDVs) with a flow rate ranging from 100 to 1000 L/min are widely used in electro-hydraulic systems (EHSs). The deadzone of the pilot stage valve and its control compensation could significantly affect the position control performance for the main stage valve that could directly affect dynamics of EHSs In this paper, it is concluded that micro flow rates exist at the intermediate position of the valve based on the analysis of the continuity equation of the flow in the control chamber of the pilot stage. The micro flow rate is helpful to eliminate the discontinuity and unsmooth domain in the previous inverse deadzone compensation function. An improved deadzone detection method is proposed to calibrate the pilot valve flow characteristics which include the micro flow rate. This new method avoids the threshold selection of the main valve spool displacement which affects the detected deadzone values. Its detection processes are realized based on the pilot flow rate characterized by the speed of the main valve spool and the pilot valve displacement characterized by the solenoid current. The deadzone compensation control strategy based on the improved deadzone detection method is also designed. The experimental results using the steady-state position tracking and sinusoidal position tracking methods are verified. It is concluded that the tracking accuracy of the main valve spool position is effectively improved with this control strategy.

11.
Biomed Chromatogr ; 33(9): e4555, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30990898

RESUMO

Bufadienolides are the main bioactive components of Venenum Bufonis (VB) and have been widely used to treat different types of human cancers for decades. The bufadienolide content in VB varies significantly in materials from different geographical origins. In this work, a new strategy for the quality assessment of VB was developed through quantitative analysis of multi-components by single marker (QAMS). Cinobufagin was selected as the internal reference substance; seven bufadienolides were separated and simultaneously determined based on relative correction factors. The correlation coefficient value (r ≥ 0.9936) between QAMS and the normal external standard method proved the consistency of the two methods. According to the outcomes of 30 batches of VB samples, the contents of the seven bufadienolides were used for further chemometric analysis. All of the samples of VB from various geographical origins were divided into three categories based on hierarchical cluster analysis and radar plot, which indicated the crucial influence of geographical origins on VB. This study showed that QAMS combined with chemometristry could be used to comprehensively evaluate and effectively control the quality of VB from different geographical origins.


Assuntos
Bufanolídeos/análise , Biomarcadores , Bufanolídeos/química , Bufanolídeos/classificação , Bufanolídeos/normas , Cromatografia Líquida de Alta Pressão , Análise por Conglomerados , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
12.
J Med Chem ; 62(6): 3088-3106, 2019 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-30843696

RESUMO

P2Y12 antagonists are widely used as antiplatelet agents for the prevention and treatment of arterial thrombosis. Based on the scaffold of a known P2Y12 antagonist AZD1283, a series of novel bicyclic pyridine derivatives were designed and synthesized. The cyclization of the ester substituent on the pyridine ring to the ortho-methyl group led to lactone analogues of AZD1283 that showed significantly enhanced metabolic stability in subsequent structure-pharmacokinetic relationship studies. The metabolic stability was further enhanced by adding a 4-methyl substituent to the piperidinyl moiety. Compound 58l displayed potent inhibition of platelet aggregation in vitro as well as antithrombotic efficacy in a rat ferric chloride model. Moreover, 58l showed a safety profile that was superior to what was observed for clopidogrel in a rat tail-bleeding model. These results support the further evaluation of compound 58l as a promising drug candidate.


Assuntos
Descoberta de Drogas , Niacina/análogos & derivados , Inibidores da Agregação Plaquetária/farmacologia , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Receptores Purinérgicos P2Y12/efeitos dos fármacos , Sulfonamidas/farmacologia , Animais , Humanos , Masculino , Niacina/química , Niacina/farmacocinética , Niacina/farmacologia , Inibidores da Agregação Plaquetária/química , Inibidores da Agregação Plaquetária/farmacocinética , Antagonistas do Receptor Purinérgico P2Y/química , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Relação Estrutura-Atividade , Sulfonamidas/química , Sulfonamidas/farmacocinética
13.
Phytomedicine ; 57: 18-29, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30668319

RESUMO

BACKGROUND: Luteolin (3,4,5,7-tetrahydroxy flavone) is a natural flavonoid abundant in fruits and vegetables. Although luteolin has shown pro-apoptotic activity in hepatocellular carcinoma (HCC) cells, the underlying molecular mechanism has not yet been clarified. PURPOSE: The aim of this study is to identify novel miRNAs involved in the action of luteolin in HCC cells and to explore the biological roles of these miRNAs. METHODS: The effect of luteolin on HCC cell growth was assessed using CCK-8 colony formation assay, flow cytometric analysis in vitro, and a xenograft model in vivo. miRNA expression profiles were assessed using next-generation sequencing. Differentially expressed miRNAs were validated by quantitative PCR. Bioinformatics analysis and luciferase reporter assay were utilized to confirm the binding of miR-6809-5p to the 3'-untranslated region (3'-UTR) of flotillin 1 (FLOT1). Furthermore, the effects of ectopic FLOT1 and miR-6809-5 expression on cell proliferation, colony formation, and cell apoptosis were also assessed. Western blotting analysis was used to detect activation of multiple signaling molecules including Erk1/2, p38, JNK, and NF-κB/p65 in the MAPK pathway. RESULTS: It was found that luteolin significantly inhibited HCC growth and caused apoptosis and cell cycle arrest at the G0/G1 phase in Huh7 cells, at the G2/M phase in HepG2 cells in vitro. Tumorigenic studies revealed that luteolin treatment significantly suppressed HCC growth in vivo. miR-6809-5p was upregulated by luteolin. Overexpression of miR-6809-5p suppressed HCC cell growth, while knockdown of miR-6809-5p reversed the anticancer effect of luteolin. With regards to its signaling mechanism, miR-6809-5p directly targets FLOT1in HCC cells. Enforced expression of FLOT1 prevented miR-6809-5p-mediated growth suppression. Downregulation of FLOT1 exerted growth-suppressive effects on HCC cells. Multiple signaling pathways including Erk1/2, p38, JNK, and NF-κB/p65 were inactivated by miR-6809-5p overexpression or FLOT1 downregulation. CONCLUSION: These findings indicated that miR-6809-5p mediates the growth-suppressive activity of luteolin in HCC, which is causally linked to FLOT1 downregulation. Induction of miR-6809-5p may provide therapeutic benefits in the treatment of HCC.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Luteolina/farmacologia , MicroRNAs/genética , Animais , Apoptose/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Proteínas de Membrana/genética , Camundongos Nus , Transdução de Sinais , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Chem Sci ; 10(47): 10894-10899, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-32180921

RESUMO

Metalla-analogues of polycyclic aromatic hydrocarbons (PAHs) have captivated chemists with their fascinating structures and unique electronic properties. To date, metallabenzene, metallanaphthalene and metallaanthracene have been reported. Metalla-analogues with more complicated fused rings have rarely been reported. Herein, we have successfully synthesized a series of new iridafluoranthenes and fused-ring iridafluoranthenes ranging from pentacyclic to heptacyclic metallaaromatic hydrocarbons in high yields under mild reaction conditions for the first time. Their photophysical and redox properties were also explored using UV-vis spectroscopy and electrochemistry combined with TD-DFT calculations. The present work may offer an important guideline for the design and construction of new polycyclic metallaaromatic hydrocarbons and metalla-nanographenes.

15.
Chem Sci ; 11(3): 896, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-34123068

RESUMO

[This corrects the article DOI: 10.1039/C9SC03914G.].

16.
Proc Natl Acad Sci U S A ; 115(39): E9230-E9238, 2018 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-30201709

RESUMO

Recombinant tissue plasminogen activator (tPA) is a Food and Drug Administration-approved thrombolytic treatment for ischemic stroke. tPA is also naturally expressed in glial and neuronal cells of the brain, where it promotes axon outgrowth and synaptic plasticity. However, there are conflicting reports of harmful versus neuroprotective effects of tPA in acute brain injury models. Furthermore, its impact on white matter integrity in preclinical traumatic brain injury (TBI) has not been thoroughly explored, although white matter disruption is a better predictor of long-term clinical outcomes than focal lesion volumes. Here we show that the absence of endogenous tPA in knockout mice impedes long-term recovery of white matter and neurological function after TBI. tPA-knockout mice exhibited greater asymmetries in forepaw use, poorer sensorimotor balance and coordination, and inferior spatial learning and memory up to 35 d after TBI. White matter damage was also more prominent in tPA knockouts, as shown by diffusion tensor imaging, histological criteria, and electrophysiological assessments of axon conduction properties. Replenishment of tPA through intranasal application of the recombinant protein in tPA-knockout mice enhanced neurological function, the structural and functional integrity of white matter, and postinjury compensatory sprouting in corticofugal projections. tPA also promoted neurite outgrowth in vitro, partly through the epidermal growth factor receptor. Both endogenous and exogenous tPA protected against white matter injury after TBI without increasing intracerebral hemorrhage volumes. These results unveil a previously unappreciated role for tPA in the protection and/or repair of white matter and long-term functional recovery after TBI.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Ativador de Plasminogênio Tecidual/uso terapêutico , Substância Branca/efeitos dos fármacos , Animais , Lesões Encefálicas Traumáticas/patologia , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fibras Nervosas/efeitos dos fármacos , Rede Nervosa/efeitos dos fármacos , Proteínas Recombinantes , Substância Branca/patologia
17.
Chemistry ; 24(33): 8375-8381, 2018 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-29572996

RESUMO

Metallacycles with chelating polydentate conjugated-carbon chain ligands are called carbolong complexes, which are expected to have interesting properties. In this work, the preparation of 12-carbon carbolong complexes in which all of the coordinated atoms in the equatorial plane are carbon atoms was studied. With the help of the well-established mechanism, a new approach to prepare coplanar carbolong complexes bearing different organic functional groups was developed by adding different terminal alkynes in sequence. In the presence of HBF4 , these coplanar carbolong complexes were converted to η3 -allyl osmapentalene derivatives, which can be produced directly from the reaction of cyclopropaosmapentalene 1 with terminal alkynes in the presence of AgBF4 under anhydrous conditions. This study offers a new route for the preparation of functional osmium carbolong complexes with excellent photothermal properties, which can be used to prepare photothermal materials.

18.
Biochem Biophys Res Commun ; 496(2): 515-522, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29353037

RESUMO

In this study, we provided evidence that curcumin could be a promising therapeutic agent for ischemic stroke by activating neuroprotective signaling pathways. Post oxygen and glucose deprivation/reoxygenation (OGD/R), primary mouse cortical neurons treated with curcumin exhibited a significant decrease in cell death, LDH release and enzyme caspase-3 activity under OGD/R circumstances, which were abolished by flotillin-1 downregulation or extracellular signal-regulated kinase (ERK) inhibitor. Moreover, flotillin-1 knockdown led to suppression of curcumin-mediated ERK phosphorylation under OGD/R condition. Based on these findings, we concluded that curcumin could confer neuroprotection against OGD/R injury through a novel flotillin-1 and ERK1/2 pathway.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Curcumina/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Animais , Isquemia Encefálica/metabolismo , Células Cultivadas , Córtex Cerebelar/citologia , Córtex Cerebelar/efeitos dos fármacos , Feminino , Glucose/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Neurônios/metabolismo , Oxigênio/metabolismo , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo
19.
J Am Chem Soc ; 139(41): 14344-14347, 2017 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-28872866

RESUMO

To explore the charge transport through metalla-aromatics building blocks, three metallacycles complexes were synthesized, and their single-molecule conductances were characterized by using mechanically controllable break junction technique. It is found that the conductance of the metallacycles junction with phosphonium group is more than 1 order of magnitude higher than that without phosphonium group. X-ray diffraction and UV-vis absorption spectroscopy suggested that the attached phosphonium group makes metallacycles more delocalized, which shortened the preferred charge transport pathway and significantly enhanced the single-molecule conductance. This work revealed that the delocalization of metalla-aromatics could be used to switch the charge transport pathway of single-molecule junctions and thus tune the charge transport abilities significantly.

20.
Chemistry ; 23(26): 6426-6431, 2017 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-28295698

RESUMO

Metalla-aromatics are attractive species because they exhibit the properties of both organometallics and aromatics. Reported metal-bridged polycyclic aromatic complexes, as well as Möbius aromatic species, are still rare. Herein, we present the construction of two new metal-bridged polycyclic aromatic frameworks, α-metallapentalenofurans and lactone-fused metallapentalynes, by the reactions of osmapentalyne with terminal aryl alkynes in the presence of H2 O or HBF4 /H2 O, respectively. DFT calculations show that the α-metallapentalenofurans possess rare planar Craig-type Möbius aromaticity derived from the 11-center-12-electron dπ -pπ π-conjugation. This study offers a new route for the construction of polycyclic metalla-aromatics as well as planar Möbius aromatic species.


Assuntos
Complexos de Coordenação/química , Furanos/química , Lactonas/química , Metais/química , Alcinos/química , Cristalografia por Raios X , Conformação Molecular , Osmio/química , Hidrocarbonetos Policíclicos Aromáticos/química , Teoria Quântica
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