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1.
Org Lett ; 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32392417

RESUMO

Norcorrole is a ring-contracted porphyrinoid, exhibiting distinct antiaromaticity. Herein, we report the reactions of meso-dimesitylnorcorrole Ni(II) complex with two types of carbenes: dichlorocarbene and an N-heterocyclic carbene (NHC). The reaction with in-situ-generated dichlorocarbene resulted in the double insertion of two chloromethine units to provide a mixture of 5,15-dichloroporphyrin and chlorinated isopyricorroles. The nucleophilic NHC attacked the 3-position of the norcorrole core and the subsequent proton transfer furnished a nonconjugated macrocycle incorporating a diazafulvene segment.

2.
EBioMedicine ; 54: 102715, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32251998

RESUMO

BACKGROUND: Hypertrophic scar (HS) is characterized by the increased proliferation and decreased apoptosis of myofibroblasts. Myofibroblasts, the main effector cells for dermal fibrosis, develop from normal fibroblasts. Thus, the stimulation of myofibroblast apoptosis is a possible treatment for HS. We aimed to explore that whether over-activated myofibroblasts can be targeted for apoptosis by anticancer drug elesclomol. METHODS: 4',6-diamidino-2-phenylindole staining, flow cytometry, western blotting, collagen gel contraction and immunofluorescence assays were applied to demonstrate the proapoptotic effect of elesclomol in scar derived myofibroblasts and TGF-ß1 induced myofibroblasts. The therapeutic potential of elesclomol was investigated by establishing rabbit ear hypertrophic scar models. FINDINGS: Both 4',6-diamidino-2-phenylindole staining and flow cytometry indicated that elesclomol targets myofibroblasts in vitro. Collagen gel contraction assay showed that elesclomol inhibited myofibroblast contractility. Flow cytometry and western blot analysis revealed that elesclomol resulted in excessive intracellular levels of reactive oxygen species(ROS), and caspase-3 and cytochrome c proteins. Moreover, compared with the control group, the elesclomol group had a significantly lower scar elevation index in vivo. Immunofluorescence assays for TUNEL and α-smooth muscle actin indicated that elesclomol treatment increased the number of apoptotic myofibroblasts. INTERPRETATION: The above results indicate that elesclomol exerted a significant inhibitory effect on HS formation via targeted myofibroblast apoptosis associated with increased oxidative stress. Thus, elesclomol is a promising candidate drug for the treatment of myofibroblast-related diseases such as HS.

3.
Int J Infect Dis ; 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32339723

RESUMO

OBJECTIVE: The outbreak of coronavirus disease 2019 (COVID-19) in China has been basically controlled. However, the global epidemic of COVID-19 is worsening. We established a method to estimate instant case fatality rate and cure rate of COVID-19 in China. METHODS: We collected 82735 confirmed cases released officially by Chinese authorities from Dec 8, 2019 to April 18, 2020. The estimated diagnosis dates of deaths and cured cases were calculated based on median cure time or median death time of individual cases. Afterward, instant fatality rate was calculated according to the number of deaths and cured cases on the same estimated diagnosis date. RESULTS: In China, the instant case fatality rate of COVID-19 was 3.8-14.6% from Jan 1 to Jan 17, and then gradually declined and stabilized at 5.7% in April. The average case fatality rate in China was 6.1%±2.9%. While, the case fatality rate was 1.0±0.4% in China except Hubei. The cure rates of COVID-19 were 93.9%±2.9% in China, and stabilized at 94.3%, while it was 99.0%±0.4% in China except Hubei. CONCLUSION: The instant case fatality rate of COVID-19 in China was much higher than that in China except Hubei. The case fatality rate of COVID-19 in China was underestimated.

4.
J Cell Mol Med ; 24(2): 2070-2072, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31802598

RESUMO

N6-methyladenosine (m6 A) is one of the most abundant messenger RNA (mRNA) modifications in eukaryotes and is involved in various key processes of RNA metabolism. In this issue of Nature, Ries et al (2019) described the fundamental features of m6A modification of mRNAs in regulating the composition of the phase-separated transcriptome on the basis of number and distribution, and provide strong evidence that m6A plays a role in regulating phase separation in cells.

5.
Front Physiol ; 10: 1101, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31555142

RESUMO

Hypertrophic scars are pathological scars that result from abnormal responses to trauma, and could cause serious functional and cosmetic disability. To date, no optimal treatment method has been established. A variety of cell types are involved in hypertrophic scar formation after wound healing, but the underlying molecular mechanisms and cellular origins of hypertrophic scars are not fully understood. Macrophages are major effector cells in the immune response after tissue injury that orchestrates the process of wound healing. Depending on the local microenvironment, macrophages undergo marked phenotypic and functional changes at different stages during scar pathogenesis. This review intends to summarize the direct and indirect roles of macrophages during hypertrophic scar formation. The in vivo depletion of macrophages or blocking their signaling reduces scar formation in experimental models, thereby establishing macrophages as positive regulatory cells in the skin scar formation. In the future, a significant amount of attention should be given to molecular and cellular mechanisms that cause the phenotypic switch of wound macrophages, which may provide novel therapeutic targets for hypertrophic scars.

7.
J Cell Physiol ; 234(12): 21662-21669, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31106425

RESUMO

Abnormal wound healing is likely to induce the formation of hypertrophic scars and keloids, which leads to dysfunction, deformity, and mental problem in the patients. Despite the advances in prevention and management of hypertrophic scar and keloids, the mechanism underlying scar and keloid formation has not been fully elucidated. Recent insights into the role of the epithelial-mesenchymal transition (EMT) in development, wound healing, stem cell regulation, fibrosis, and tumorigenesis have increased our understanding of the pathophysiology of hypertrophic scarring and keloids and suggested new therapeutic targets. This review summarizes recent progress in the elucidation of the role of EMT in physiologic wound healing and pathologic scar formation. This knowledge will facilitate an understanding of EMT roles in scar formation and shed new light on the modulation and potential treatment of hypertrophic scars and keloids.

8.
Chemistry ; 25(32): 7618-7622, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31001885

RESUMO

The synthesis of antiaromatic NiII -norcorroles having primary, secondary, and tertiary alkyl groups at the reactive meso-positions was attempted. Reductive coupling of a NiII -dipyrrin precursor provided NiII -meso-dihexylnorcorrole, which underwent substantial degradation on silica gel. Introduction of tert-butyl groups was unsuccessful due to the difficult preparation of the corresponding dipyrrin precursor. Meanwhile, NiII -norcorroles with isopropyl and cyclohexyl groups were isolated as stable molecules under ambient conditions. Furthermore, we found that oxidation of NiII -meso-dialkylnorcorroles with hydrogen peroxide in the presence of sodium carbonate gave NiII -5-oxaporphyrins(2.0.1.0). In contrast, oxidation of NiII -meso-dimesitylnorcorrole under the same reaction conditions gave 10-oxaporphyrin(1.1.1.0). The contrasting reactivity can be attributed to the steric congestion around the meso-positions.

9.
AIDS ; 33(9): 1431-1439, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30889014

RESUMO

OBJECTIVE: The current study aimed to understand epidemiological feature and critical factors associated with pathogenesis of circulating recombinant form (CRF) 01_AE strains in Northeast China. DESIGN: Compared analysis was made between CRF01_AE and non-CRF01_AE samples to understand the pathogenicity features of CRF01_AE. Further analyses between CRF01_AE samples with high or low CD4 cell counts and between samples with different coreceptor usages were done to explore the possible factors correlating to the pathogenesis of CRF01_AE viruses. METHODS: The genotypes of newly identified strains were determined by phylogenetic analyses using Mega 6.06. Coreceptor usage was predicted by Geno2Pheno algorithm. Potential N-linked glycosylation site (PNGS) number was calculated using the online N-glycosite software. The properties of amino acid sequences were analyzed by the online ProtParam tool. RESULTS: CRF01_AE become the main HIV-1 genotype since 2010. Compared with non-CRF01_AE group, the CRF01_AE group showed a higher proportion of samples with CD4 cell count less than 200 cells/µl. Shorter amino acid length, fewer PNGSs and the presence of a basic motif R/KNXT or NR/KT in V4 correlated to a lower CD4 cell count, and existence or coexistence of Thr12, Arg13, Val21 and Lys33, presence of more than 4 of net charges and lack of the PNGS within V3 favored to the X4/R5X4 coreceptor usage of CRF01_AE viruses. CONCLUSION: CRF01_AE has dominated HIV-1 genotype in Northeast China. Infection with CRF01_AE exhibited a fast disease progression, which may be associated with specific amino acid residues and PNGSs in V3 and V4 regions as well as amino acid length of V4 region.

10.
Eur J Med Chem ; 155: 806-823, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29957526

RESUMO

Human sirtuin 2 (SIRT2) is a nicotinamide adenine dinucleotide (NAD+)-dependent deacylase, and is implicated in human diseases including cancer. Selective small-molecule inhibitors for SIRT2 are sought as chemical tools and potential therapeutics. Here we report the X-ray crystal structure guided structure-activity relationship studies of new N-(3-(phenoxymethyl)phenyl)acetamide derivatives with SIRT2, which led to the identification of potent, selective SIRT2 inhibitors. Crystallographic analyses reveal that the new inhibitors act via inducing the formation of an enlarged hydrophobic pocket and particularly mimicking the interactions made by myristoylated-lysine substrates. The most potent inhibitor 24a could dose-dependently elevate the acetylation level of α-tubulin in the non-small cell lung cancer H441 cells, which have a high expression level of SIRT2 as determinated by Western blotting analyses. Further cellular assays reveal that 24a restrains cell growth mainly through inhibiting cellular proliferation rather than inducing apoptosis. Moreover, 24a could suppress the migration and invasion of H441 cells. These results provide an excellent basis for further development of new potent, selective, and cell active SIRT2 inhibitors as chemical tools and potential therapeutics for SIRT2-driven non-small cell lung cancers.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Descoberta de Drogas , Inibidores de Histona Desacetilases/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Sirtuína 2/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Modelos Moleculares , Estrutura Molecular , Sirtuína 2/metabolismo , Relação Estrutura-Atividade , Células Tumorais Cultivadas
11.
AIDS Res Hum Retroviruses ; 34(8): 709-713, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29724111

RESUMO

This study reported a new HIV-1 circulating recombinant form CRF65_cpx virus isolated from a man who have sex with men (MSM) in Jilin, China. The near full-length genome of this virus was composed of 14 mosaic gene fragments derived from CRF01_AE, subtype B' (Thai B) and subtype C, highly similar to the CRF65_cpx viruses recently identified in Yunnan and Anhui of China. Phylogenetic tree analysis suggested that this CRF65_cpx strain was not generated among MSM in Jilin, but originated in southern regions of China and spread to Jilin by MSM population. The emergence of CRF65_cpx in Jilin indicated HIV-1 epidemic in this area was more and more complicated and the MSM population has become the important source for generation of new recombinant viruses. Real-time surveillance of new HIV-1 infections among MSM population is quite required.


Assuntos
Genótipo , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/isolamento & purificação , Recombinação Genética , Adulto , China/epidemiologia , Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , HIV-1/genética , Homossexualidade Masculina , Humanos , Masculino , Epidemiologia Molecular , Filogenia
12.
AIDS Res Hum Retroviruses ; 34(8): 714-718, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29786452

RESUMO

The current HIV-1 epidemic in China is featured by diverse subtypes and continual emergence of new recombinant viruses. This study identified a novel unique recombinant form (URF), JL16013, among men who have sex with men (MSM) in Jilin, China. The JL16013 virus was different from all known subtypes and set up a distinct branch on the phylogenetic tree. This virus had a CRF01_AE backbone with two subtype B' fragments and one CRF65_cpx fragment inserted into gag, pol, env, and nef regions, suggesting that this novel URF might have originated from the CRF01_AE, subtype B', and CRF65_cpx viruses that were cocirculating in Jilin province. This was the first report of the CRF01_AE/B'/CRF65_cpx recombinant in China. Identification of this URF indicated the severity and complexity of the HIV-1 epidemic among MSM in Jilin province. Timely surveillance of new HIV-1 infections and new recombinants among the MSM population is urgently required.


Assuntos
Genótipo , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/isolamento & purificação , Recombinação Genética , Adulto , China , HIV-1/genética , Homossexualidade Masculina , Humanos , Masculino , Filogenia , Análise de Sequência de DNA
13.
Cell Physiol Biochem ; 47(2): 458-474, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29794432

RESUMO

BACKGROUND/AIMS: Sepsis is a severe and complicated syndrome that is characterized by dysregulation of host inflammatory responses and organ failure. Cystathionine-γ-lyase (CSE)/ hydrogen sulfide (H2S) has potential anti-inflammatory activities in a variety of inflammatory diseases. NADPH oxidase 4 (Nox4), a member of the NADPH oxidases, is the major source of reactive oxygen species (ROS) and its expression is increased in sepsis, but its function in CSE-mediated anti-inflammatory activities remains unknown. METHODS: Macrophages were either transfected with CSE, Nox4 siRNA or transduced with lentiviral vector encoding CSE or Nox4, and then stimulated with lipopolysaccharide (LPS). The expression of inflammatory mediators and signaling pathway activation were measured by quantitative PCR (qPCR), ELISA, and immunoblotting. LPS-induced shock severity in WT, Nox4 knockdown and CSE knockout (CSE-/-) mice was assessed. RESULTS: Here we showed that CSE and Nox4 were upregulated in macrophage and mouse in response to LPS. After LPS stimulation, the inflammatory responses were significantly ameliorated by lentiviral Nox4 shRNA knockdown, but were exacerbated by lentiviral overexpressing Nox4. Furthermore, Nox4 mediated inflammation through PI3K/Akt and p-p38 mitogen-activated protein kinase signal pathway. Notably, CSE knockout served to amplify the inflammatory cascade by increasing Nox4-ROS signaling activation in septic mice and macrophage. Similarly, the enhanced production of inflammatory mediators by macrophages was reduced by CSE overexpression. CONCLUSION: Thus, we demonstrated that CSE/H2S attenuated LPS-induced sepsis against oxidative stress and inflammation damage probably largely through mediated Nox4 pathway.


Assuntos
Sulfeto de Hidrogênio/farmacologia , Lipopolissacarídeos/farmacologia , NADPH Oxidase 4/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Animais , Cistationina gama-Liase/deficiência , Cistationina gama-Liase/genética , Citocinas/análise , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NADPH Oxidase 4/antagonistas & inibidores , NADPH Oxidase 4/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células RAW 264.7 , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
14.
Cell Physiol Biochem ; 46(3): 907-924, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29669336

RESUMO

BACKGROUND/AIMS: Chloride intracellular channel 1 (CLIC1), which is a member of the chloride channel protein family, is associated with various human tumors. Recent studies have shown that CLIC1 is involved in the occurrence and development of gastric cancer (GC). However, the exact mechanism remains unclear in GC. METHODS: Effects of CLIC1 on the progression of GC in vivo and in vitro and the potential underlying mechanisms have been investigated by analysing 54 patients with GC, as well as human gastric cell lines SGC-7901 and MGC-803, utilizing proteomics, RT-PCR, Western blotting, flow cytometry, Cell invasion and migration assays and xenograft tumor models. RESULTS: Our study shows that CLIC1 knockdown by targeted-siRNA markedly inhibits GC cell invasion and migration and induces apoptosis in vitro. In total, 54 differentially expressed proteins were identified in GC cells SGC-7901 after CLIC1 silencing by isobaric tags for relative isotope labeled and absolute quantitation (iTRAQ) technology, including integrin α1 (ITGα1) and ITGα3. The expression levels of ITGα3, ITGαv, ITGß1 and Bcl-2 mRNA and protein were decreased significantly in GC cells after CLIC1 knockdown; ITGα1 and Fas were upregulated, but the level of survivin was not significantly different. GC growth and metabolism were decreased in vivo after CLIC1 silencing, but apoptosis was markedly increased. Further study showed that the expression levels of ITGα3, ITGαv and ITGß1, as well as AKT-phosphorylation, ERK-phosphorylation and p38-phosphorylation, were reduced in vivo after CLIC1 knockdown, while ITGα1 was upregulated. CONCLUSIONS: We speculate that CLIC1 may play an important role in the progression of GC, and its mechanism may be related to the regulation of integrin family proteins, which leads to the sequential regulation of the PI3K/AKT, MAPK/ERK and MAPK/p38 pathways.


Assuntos
Canais de Cloreto/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias Gástricas/diagnóstico , Idoso , Animais , Apoptose , Linhagem Celular Tumoral , Canais de Cloreto/antagonistas & inibidores , Canais de Cloreto/genética , Regulação para Baixo , Feminino , Humanos , Cadeias alfa de Integrinas/genética , Cadeias alfa de Integrinas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Interferência de RNA , Transdução de Sinais , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Regulação para Cima
15.
Chemistry ; 24(26): 6798-6803, 2018 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-29575314

RESUMO

A new hexadecahedron assembled by core-shell CoS2 particles@N-doped carbon (CoS2 @NCH) is prepared successfully through the self-templating method. The CoS2 @NCH hybrid electrode delivers a high lithium-storage capacity of 778 mA h g-1 after 1000 cycles at a high current density of 1 A g-1 , which is the longest cycle lifespan among the reported CoS2 anode materials in lithium-ion batteries. Furthermore, the CoS2 @NCH hybrid electrode shows excellent rate capability with a discharge capacity of 220 mA h g-1 at an extremely high current density of 20 A g-1 , and a charge capacity of 649 mA h g-1 is restored upon returning the current density back to 2 A g-1 . The superior performance is attributed to the unique construction of CoS2 @NCH. The N-doped interconnected porous carbon shells form highly conductive skeletons for quick electron transfer and prevent the electrode from collapsing. Moreover, the porous characteristic of the materials plays a key role: as some effective channels, the mesopores on the porous carbon shells provide greater access for lithium, and the mesopores derived from the particle interspace enables the complete immersion of the electrodes in electrolyte, which alleviates the volume expansion and ensures the integrity of the electrode. In addition, the nanosized CoS2 particles, which shorten the ion-transport path and provide extra electroactive sites, also improve the reaction kinetics.

16.
ACS Appl Mater Interfaces ; 10(1): 509-516, 2018 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-29243916

RESUMO

A three-layered cathode structure was designed to minimize the shuttle effect of polysulfides and improve active material utilization. The three-layered configuration was fabricated by directly dropping pure sulfur composite slurry into multifunctional dual-barrier layers consisting of a self-standing TiO2/C interlayer and a very thin acetylene black layer (0.35 mg cm-2). In consequence, a decent discharge capacity of 963 mA h g-1 was acquired after 100 cycles at 0.1 C. With cycling at 0.1, 0.2, 0.5, 1, and 2 C, the cells displayed excellent reversible capacities of 1203, 1145, 1035, 934, and 820 mA h g-1, respectively. Furthermore, the cells still delivered a satisfactory discharge capacity of 799 mA h g-1 after 300 cycles at 0.5 C. The light mass of the three-layered configuration guarantees that the energy density is effectively improved, considering the overall mass of the cathode. The energy density (603 W h kg-1 after 100 cycles) was at a high level compared with those of the reported ones. Therefore, it is believed that the synergistic design for the three-layered cathode structure, which combines the mass-produced layer-by-layer structure, provides a novel protocol to the practical application of lithium-sulfur batteries.

17.
Neurochem Res ; 42(10): 2850-2860, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28512713

RESUMO

Chronic neuroinflammation is a pathological feature of neurodegenerative diseases. Inhibition of microglia-mediated neuroinflammation might be a potential strategy for neurodegeneration. Matairesinol, a dibenzylbutyrolactone plant lignan, presents in a wide variety of foodstuffs. It has been found to possess anti-angiogenic, anti-oxidative, anti-cancer and anti-fungal activities. In the present study, we investigated the anti-neuroinflammation effects of matairesinol on lipopolysaccharide (LPS)-induced BV2 microglia cells and the related molecular mechanisms. The results showed that matairesinol inhibited microglia activation by reducing the production of nitric oxide, the expression of inducible nitric oxide synthase and cyclooxygenase-2 in a concentration-dependent manner (6.25, 12.5, 25 µM). In the molecular signaling pathway, LPS-induced nuclear factor-kappa B (NF-κB) transcriptional activity and translocation into the nucleus were remarkably suppressed by matairesinol through the inhibition of the extracellular signal-regulated kinase (ERK)1/2 signal transduction pathways, but not p38 MAPK or c-jun N-terminal kinase (JNK). Meanwhile, matairesinol also blocked LPS-mediated microglia migration and this was associated with inhibition of LPS-induced Src phosphorylation as well as Src expression in a concentration-dependent manner. Taken together, these results suggest that matairesinol inhibited inflammatory response and migration in LPS-induced BV2 microglia, and the mechanisms may be associated with the NF-κB activation and modulation of Src pathway.


Assuntos
Furanos/farmacologia , Lignanas/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Microglia/efeitos dos fármacos , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Anti-Inflamatórios/farmacologia , Lipopolissacarídeos/farmacologia , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/efeitos dos fármacos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Proteína Oncogênica pp60(v-src)/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo
18.
Chemistry ; 23(40): 9666-9673, 2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28508401

RESUMO

In this work, oxygen-deficient anatase TiO2 nanosheets (A-TiO2-x NSs) are proposed as a substrate to improve the electrochemical properties of sulfur electrodes for lithium-sulfur (Li-S) batteries. The A-TiO2-x NSs are prepared by partly reducing pristine TiO2 nanosheets (A-TiO2 NSs) in NaBH4 solution. With some oxygen vacancies on the surface of the TiO2 nanosheets, A-TiO2-x NSs not only promote electronic transfer, but also act as more effective polysulfide reservoirs to minimize the dissolution of lithium polysulfides (LiPSs) than the A-TiO2 NSs control. Hence, upon utilization as modifiers for cathodes of Li-S batteries, the A-TiO2-x NSs-modified sulfur (A-TiO2-x NSs-S) cathode exhibits a higher reversible specific capacity and greater cycling performance and rate capability than the A-TiO2 NSs-modified one (A-TiO2 NSs-S). For example, A-TiO2-x NSs-S delivers an initial specific capacity of 1277.1 mAh g-1 at 0.1 C and maintains a stable Coulombic efficiency of approximately 99.2 % after the first five cycles; these values are higher than those of 997.3 mAh g-1 and around 96.7 %, respectively, for A-TiO2 NSs-S. The enhanced electrochemical properties of the A-TiO2-x NSs-S cathode can be ascribed mainly to the more effective adsorption of dissolvable and diffused LiPSs by the oxygen vacancies. Therefore, utilization of the structure of oxygen vacancies in Li-S batteries demonstrates great prospects for practical application.

19.
Chemistry ; 23(36): 8712-8718, 2017 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-28452106

RESUMO

Bimetallic transition-metal oxides, which exhibit superior electrochemical properties compared with pristine single-metal oxides, have recently become a topic of significant research interest for applications in lithium-ion batteries (LIBs). Herein, we report a simple and scalable electrospinning method to synthesize porous CoTiO3 nanofibers as the precursor for nanostructured bimetallic transition-metal oxides formed electrochemically in situ. This strategy ensures uniform mixing and perfect contact between two constituent transition-metal oxides during the lithiation/delithiation process. Furthermore, CoTiO3 nanofibers based on ultrafine CoTiO3 nanocrystals are interconnected to form a nano/microstructured 3D network, which ensures the high stability of the in situ formed structure composed of bimetallic transition-metal oxides, and also fast ion/electron transfer and electrolyte penetration into the electrode. Electrochemical measurements revealed the excellent lithium storage (647 mAh g-1 at 0.1 Ag-1 ) and retention properties (600 mAh g-1 at 1 Ag-1 after 1200 cycles) of the CoO/TiO2 electrode. Moreover, the electrochemical reaction mechanism was explored by using ex situ X-ray photoelectric spectroscopy and cyclic voltammetry tests, which confirmed the two-phase reaction processes in the electrodes. These results clearly validate the potential of CoTiO3 with a unique nano/microstructured morphology as the precursor for a bimetallic transition-metal oxide for use as the anode material for long-life LIBs.

20.
Biomed Pharmacother ; 88: 878-884, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28178617

RESUMO

The objective of the current study was to evaluate the anti-inflammatory effects of shizukaol B, a lindenane-type dimeric sesquiterpene isolated from the whole plant of Chloranthus henryi, on lipopolysaccharide (LPS)-induced activation of BV2 microglial cells in vitro. Our data showed that shizukaol B concentration-dependently suppressed expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) in LPS-stimulated BV2 microglia. Meanwhile, shizukaol B concentration- and time-dependently inhibited LPS-mediated c-Jun N-terminal kinase 1/2 (JNK) activation, but had little effect on extracellular signal-regulated kinase 1/2 or p38 phosphorylation. Furthermore, shizukaol B significantly blocked LPS-induced activator protein-1 (AP-1) activation, evidenced by reduced phosphorylation and nuclear translocation of c-Jun and DNA binding activity of AP-1. Taken together, our findings suggest that shizukaol B exerts anti-inflammatory effects in LPS-activated microglia partly by modulating JNK-AP-1 signaling pathway.


Assuntos
Mediadores da Inflamação/metabolismo , Inflamação/patologia , Microglia/patologia , Sesquiterpenos/farmacologia , Traqueófitas/química , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ciclo-Oxigenase 2/metabolismo , Ativação Enzimática/efeitos dos fármacos , Inflamação/metabolismo , Lipopolissacarídeos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Microglia/efeitos dos fármacos , Microglia/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase Tipo II/metabolismo , Fosforilação/efeitos dos fármacos , Sesquiterpenos/química , Fatores de Tempo , Fator de Transcrição AP-1/metabolismo
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