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1.
Phys Chem Chem Phys ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32068766

RESUMO

The successful synthesis and isolation of cyclo-C18 in experiments is a ground-breaking development in carbon rings. Herein, we studied the thermodynamic stabilities of cyclo-Cn (4 ≤ n ≤ 34) with hybrid density functional theory. When n = 4N + 2 (N is an integer), cyclo-Cn were thermodynamically stable. In particular, cyclo-C10 and cyclo-C14 were more thermodynamically, kinetically, dynamically, and optically stable compared with the acknowledged cyclo-C18, and were potential candidates for zero-dimensional carbon rings. Cyclo-Cn (n = 10 and 14) show similar molecular semiconductor characteristics to the acknowledged cyclo-C18. The carbon atoms were sp hybridized in cyclo-C10, cyclo-C14, and cyclo-C18. Cyclo-C14 and cyclo-C18 had alternating abnormal single and triple bonds, but cyclo-C10 had equal bonds. Cyclo-C10, cyclo-C14, and cyclo-C18 with large aromaticities had out-of-plane and in-plane π systems, which were perpendicular to each other. The number of π electrons in the out-of-plane and in-plane π systems, respectively, followed the standard Hückel aromaticity rule. Simulated UV-vis-NIR spectra indicated similar electronic structures of cyclo-C14 and cyclo-C18.

2.
Microbes Environ ; 35(1)2020.
Artigo em Inglês | MEDLINE | ID: mdl-31932537

RESUMO

Vigna is a genus of legumes cultivated in specific areas of tropical countries. Species in this genus are important crops worldwide. Vigna species are of great agronomic interest in Venezuela because Vigna beans are an excellent alternative to other legumes. However, this type of crop has some cultivation issues due to sensitivity to acidic soils, high temperatures, and salinity stress, which are common in Venezuela. Vigna species establish symbioses mainly with Bradyrhizobium and Ensifer, and Vigna-rhizobia interactions have been examined in Asia, Africa, and America. However, the identities of the rhizobia associated with V. radiata and V. unguiculata in Venezuela remain unknown. In the present study, we isolated Venezuelan symbiotic rhizobia associated with Vigna species from soils with contrasting agroecosystems or from fields in Venezuela. Several types of soils were used for bacterial isolation and nodules were sampled from environments characterized by abiotic stressors, such as high temperatures, high concentrations of NaCl, and acidic or alkaline pH. Venezuelan Vigna-rhizobia were mainly fast-growing. Sequencing of several housekeeping genes showed that in contrast to other continents, Venezuelan Vigna species were nodulated by rhizobia genus including Burkholderia, containing bacteria from several new phylogenetic lineages within the genus Bradyrhizobium. Some Rhizobium and Bradyrhizobium isolates were tolerant of high salinity and Al toxicity. The stress tolerance of strains was dependent on the type of rhizobia, soil origin, and cultivation history. An isolate classified as R. phaseoli showed the highest plant biomass, nitrogen fixation, and excellent abiotic stress response, suggesting a novel promising inoculant for Vigna cultivation in Venezuela.


Assuntos
Filogenia , Proteobactérias/classificação , Proteobactérias/fisiologia , Microbiologia do Solo , Simbiose , Vigna/microbiologia , DNA Bacteriano/genética , Genes Bacterianos/genética , Fixação de Nitrogênio/genética , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Nódulos Radiculares de Plantas/microbiologia , Análise de Sequência de DNA , Solo/química , Estresse Fisiológico , Venezuela , Vigna/crescimento & desenvolvimento
3.
Sci Rep ; 10(1): 104, 2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31919399

RESUMO

Ascorbic acid-2-phosphate (A2-P) is an oxidation-resistant derivative of ascorbic acid that has been widely employed in culturing adipose-derived stem cells (ASCs) for faster expansion and cell sheet formation. While high dose ascorbic acid is known to induce cellular apoptosis via metabolic stress and genotoxic effects, potential cytotoxic effects of A2-P at high concentrations has not been explored. In this study, the relationship between ASC seeding density and A2-P-induced cytotoxicity was investigated. Spheroid-derived ASCs with smaller cellular dimensions were generated to investigate the effect of cell-cell contact on the resistance to A2-P-induced cytotoxicity. Decreased viability of ASC, fibroblast, and spheroid-derived ASC was noted at higher A2-P concentration, and it could be reverted with high seeding density. Compared to control ASCs, spheroid-derived ASCs seeded at the same density exhibited decreased viability in the A2-P-supplemented medium. The expression of antioxidant enzymes (catalase, SOD1, and SOD2) was enhanced in ASCs at higher seeding densities. However, their enhanced expression in spheroid-derived ASCs was less evident. Furthermore, we found that co-administration of catalase or N-acetylcysteine nullified the observed cytotoxicity. Collectively, A2-P can induce ASC cytotoxicity at higher concentrations, which can be prevented by seeding ASCs at high density or co-administration of another antioxidant.

4.
J Orthop Surg (Hong Kong) ; 28(1): 2309499019899572, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31994966

RESUMO

Tibiotalocalcaneal (TTC) arthrodesis with retrograde nail is a widely used treatment option for severe ankle arthropathy. With inherent biomechanical benefits in axial loading and strong bending stiffness, high union rate and good clinical outcomes have been reported in the literature. However, some undesired complications, such as osteomyelitis or implant failure, can develop after this procedure. Herein, we report the case of an 86-year-old man with right ankle osteomyelitis after TTC arthrodesis with retrograde nail. After removing the previous implants and extensive debridement, we used an antibiotic cement nail with multiple screws fixation as a salvage procedure in the same operation. The patient fully recovered without further surgical treatment.

5.
Am J Chin Med ; 48(1): 127-142, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31931594

RESUMO

Gelsemium elegans Benth. (G. elegans), a traditional Chinese medicine, has great potential as an effective growth promoter in animals, however, the mechanism of its actin remains unclear. Here, we evaluated the protective effects of koumine extract from G. elegans against lipopolysaccharide (LPS)-induced intestinal barrier dysfunction in IPEC-J2 cells through alleviation of inflammation and oxidative stress. MTT and LDH assays revealed that koumine significantly reduced LPS cytotoxicity. Transepithelial electrical resistance (TEER) and cell monolayer permeability assays showed that koumine treatment attenuated the LPS-induced intestinal barrier dysfunction with no particularly different effects in tight junction proteins such as ZO-1, claudin-1, and occludin. LPS-triggered inflammatory response was also suppressed by koumine, as evidenced by the downregulated inflammatory factors, including TNF-α, IL-6, IL-1ß, NO, iNOS, and COX-2, which was closely connected with the inhibition of NF-κB pathway for the decrease of phosphorylation of IκBα and NF-κB and nuclear translocation of p-p65. Amount of reactive oxygen species (ROS) and MDA induced by LPS was also reduced by koumine through activation of Nrf2 pathway, and increased in the levels of Nrf2 and HO-1 degradation of keap-1 to promote anti-oxidants, including superoxide dismutase (SOD) and catalase (CAT). To summarize, koumine-reduced the oxidative stress and inflammatory reaction triggered by LPS through regulation of the Nrf2/NF-κB signaling pathway and preventing intestinal barrier dysfunction.

6.
Microbes Environ ; 35(1)2020.
Artigo em Inglês | MEDLINE | ID: mdl-31996499

RESUMO

In central Europe, soybean cultivation is gaining increasing importance to reduce protein imports from overseas and make cropping systems more sustainable. In the field, despite the inoculation of soybean with commercial rhizobia, its nodulation is low. In many parts of Europe, limited information is currently available on the genetic diversity of rhizobia and, thus, biological resources for selecting high nitrogen-fixing rhizobia are inadequate. These resources are urgently needed to improve soybean production in central Europe. The objective of the present study was to identify strains that have the potential to increase nitrogen fixation by and the yield of soybean in German soils. We isolated and characterized 77 soybean rhizobia from 18 different sampling sites. Based on a multilocus sequence analysis (MLSA), 71% of isolates were identified as Bradyrhizobium and 29% as Rhizobium. A comparative analysis of the nodD and nifH genes showed no significant differences, which indicated that the soybean rhizobia symbiotic genes in the present study belong to only one type. One isolate, GMF14 which was tolerant of a low temperature (4°C), exhibited higher nitrogen fixation in root nodules and a greater plant biomass than USDA 110 under cold conditions. These results strongly suggest that some indigenous rhizobia enhance biological nitrogen fixation and soybean yield due to their adaption to local conditions.

7.
Nat Chem Biol ; 16(2): 150-159, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31768034

RESUMO

Covalent probes serve as valuable tools for global investigation of protein function and ligand binding capacity. Despite efforts to expand coverage of residues available for chemical proteomics (e.g., cysteine and lysine), a large fraction of the proteome remains inaccessible with current activity-based probes. Here, we introduce sulfur-triazole exchange (SuTEx) chemistry as a tunable platform for developing covalent probes with broad applications for chemical proteomics. We show modifications to the triazole leaving group can furnish sulfonyl probes with ~5-fold enhanced chemoselectivity for tyrosines over other nucleophilic amino acids to investigate more than 10,000 tyrosine sites in lysates and live cells. We discover that tyrosines with enhanced nucleophilicity are enriched in enzymatic, protein-protein interaction and nucleotide recognition domains. We apply SuTEx as a chemical phosphoproteomics strategy to monitor activation of phosphotyrosine sites. Collectively, we describe SuTEx as a biocompatible chemistry for chemical biology investigations of the human proteome.

9.
Nanoscale ; 12(2): 755-762, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31829368

RESUMO

Efficient photocatalytic conversion of CO2 into energy-rich chemicals is of great significance for both environmental conservation and alleviating the energy crisis. However, convenient synthesis of low-cost, durable and eco-friendly photocatalysts with a novel morphology or structure for highly selective photocatalytic CO2 reduction remains a challenge. Herein, Co3O4 hierarchical nanosheets were synthesized by calcination of novel cobalt metal-organic framework (MOF) nanosheets prepared by a facile oil bath method. In such Co MOF nanosheets, 1,4-naphthalenedicarboxylic acid was chosen as the organic linker, rather than the commonly used 2-methylimidazole for ZIF-67. After thermal treatment in air, the obtained Co3O4 inherited the 2D morphology of its MOF template and evolved into hierarchical nanosheets which were composed of small nanoparticles. Benefiting from the large surface area, abundant mesoporous structure and good capability towards the separation and transfer of photo-generated charge carriers induced by less internal oxygen vacancies, the Co3O4 hierarchical nanosheets showed a CO generation rate of 39.70 µmol h-1 in visible-light photocatalytic CO2 reduction, which was superior to that of Co3O4 nanoparticles and commercial Co3O4. What's more, a CO selectivity of 77.3% was achieved, which is among the highest of cobalt-based spinel oxide photocatalysts for CO2 conversion.

10.
Trends Mol Med ; 26(2): 137-140, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31862244

RESUMO

A main target in microbiome research is the understanding and ability to safely and effectively modulate the microbiome to improve health. Hereto, we discuss the role of vitamins in relation to the gut microbiome and present a rationale for the modulation of gut microbial communities via selected systemic and colon-targeted vitamin administration.

11.
J Dairy Sci ; 103(1): 87-97, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31677844

RESUMO

Previous research reported that fermented yak milk had a diverse microbial composition. For this study, raw yak milk, qula, and fermented yak milk samples were collected from the Aba Tibetan autonomous region of China. The genus and species microbial composition of these samples were analyzed by high-throughput sequencing of 16S rRNA and groEL gene amplicons, and the volatile profile of the samples was quantified by gas chromatography-mass spectrometry. The results indicated variation in abundance of microbiota at the genus level among the fermented yak milk samples, with Lactobacillus as the most abundant genus in the majority of samples, ranging from 41.6 to 98.3%. The volatile profile of the samples varied among those collected from different villages. Correlations between bacterial composition and volatile compounds of the samples were also observed. Lactobacillus displayed a significant correlation with volatile compounds such as benzaldehyde, 2,3-pentanedione, ethanol, and ethyl acetate, whereas the samples with relatively high abundance of Streptococcus and Lactococcus displayed relatively low contents of volatile compounds.

12.
Acta Bioeng Biomech ; 21(3): 57-66, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31798015

RESUMO

PURPOSE: The purpose of this study was to investigate pullout strength of three types of pedicle screws with and without cement augmentation in osteoporotic bone using finite element analysis. METHODS: Twelve 3D finite element models were created to investigate the effect of pullout strength when comparing between pedicle screw types and bone cement clouds. The bottom side of bone block model was constrained and U-shape head was applied 1 mm in direction of longitudinal axis of pedicle screw to perform pullout resistance. The material properties of the FEA was set as linear elastic, homogenous, isotropic condition. The element sensitivity of convergence testing has been performed and variation of the sequential analytical results was less than 3%. RESULTS: The results showed that the maximum total reaction force (133.8 N) was detected in the model of cannulated pedicle screw combined with a central pin with 4 ml cement augmentation, but, in contrast, the minimum total reaction force (106.8 N) was discovered in the model of cannulated pedicle screw without cement. A strong relationship (r = 0.9626) is found in comparison with the biomechanical results between pullout strength of sawbone testing and reaction forces of the FEA. CONCLUSIONS: The study concludes that the cannulated pedicle screw can not only provide an inner guider for cement flow and increase bending resistance (deflection effect) when a central pin is selected, but also can improve the pullout strength in the osteoporotic bone to add cement augmentation. The design of the cannulated pedicle screw is suggested for poor bone quality to change pullout failure.

13.
Ying Yong Sheng Tai Xue Bao ; 30(12): 4031-4040, 2019 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-31840447

RESUMO

Pinus tabuliformis is an important afforestation species in the Loess Plateau. Quick and accurate estimation of aboveground biomass (AGB) of P. tabuliformis plantations plays an important role in monitoring regional forest resources. Here, we used multi-spectral remote sensing data of domestic satellite GF-2 and the field data to estimate the aboveground biomass of P. tabuliformis plantations in Shibao forest farm of Huanglong Mountain in Shaanxi Province. We calculated eight texture features and five vegetation indices, and then built models based four texture windows (3×3, 5×5, 7×7, 9×9) by using five regression methods including normal regression, stepwise regression, ridge regression, Lasso regression and principal component regression. We used the leave-one-out cross validation (LOOCV) to test the estimation accuracy of each model. We found serious multi-collinearity relationships between the extracted remote sensing factors. Most of the remote sensing factors had significant correlations with aboveground biomass of P. tabuliformis plantations. GF-2 data could achieve higher accuracy in the inversion of aboveground biomass of P. tabuliformis plantations in the Shibao forest farm. The best estimation result was the principal component regression model using 9×9 texture window, and the worst one was the normal regression model using 3×3 texture window. Inversion of aboveground biomass of P. tabuliformis plantation using domestic high-resolution satellite imagery could provide a scientific basis for forestry biomass monitoring, resource management, and sustainable management in the forestry departments of northwest China.


Assuntos
Pinus , Biomassa , China , Florestas , Solo , Árvores
14.
Eur J Nutr ; 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31786642

RESUMO

PURPOSE: Emerging studies have reported gut microbial composition plays a key role in alleviating AD clinical symptoms during the probiotic intervention, but the correlation among clinical symptoms, immune responses and gut microbial alteration needs to be explored. Therefore, the objective was to investigate the correlation during Bifidobacterium adolescentis intervention in DNFB-induced AD mice. METHODS: The mice were randomly divided into nine groups and fed B. adolescentis for 3 weeks. At the end of the experiment, clinical and immune indicators were assessed. Flow cytometry was performed to explore the effect of B. adolescentis on regulatory T cells in the spleen. V3-V4 region of the 16S ribosomal RNA (rRNA) gene was sequenced to evaluate changes in the gut microbiota. RESULTS: Bifidobacteria adolescentis treatments reduced ear and skin thickness and suppressed eosinophils and mast cells infiltration. Th1- and Th2-type responses were regulated and the Tregs population was promoted in the spleen by B. adolescentis treatments. Bifidobacteria adolescentis increased the relative abundance of Lactobacillus but decrease Dorea and Pediococcus. Propionic and butyric acids were increased but isovaleric acid was decreased by B. adolescentis treatment. Besides, the functional modules, such as fatty acid biosynthesis, antigen processing and presentation were upregulated by B. adolescentis Ad1 treatment compared to the DNFB group. CONCLUSION: Collectively, these results imply that B. adolescentis with the role of immunomodulation promotes Treg differentiation and suppresses Th2 responses, and increases the proportion of Lactobacillus that is positively correlated to increase in propionic acid production, and thus has the potential for AD amelioration.

15.
Food Funct ; 10(11): 7588-7598, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31687714

RESUMO

Increasing evidence points to the effect of the gut microbiota on central nervous system functions. Supplementation of certain microbial strains has been demonstrated to alleviate depressive behaviors and neurological abnormalities. This study took the approach to screen for an anti-depressive Bifidobacterium longum strain from fourteen candidates and systematically verified its effect in a chronic stress-induced depression mice model. B. longum subsp. infantis strain CCFM687 could significantly enhance the biosynthesis of 5-hydroxytryptamine (5-HTP) in vitro in RIN14B cells through up-regulation of the Tph1 gene expression. Administration of CCFM687 in mice significantly improved the scores in behavioral tests and increased the level of 5-HTP and serotonin (5-HT) in the prefrontal cortex (PFC) of the brain. The brain-derived neurotrophic factor (BDNF) in the PFC was also increased, possibly through the 5-HT1A-CREB-BDNF pathway. In addition, CCFM687 alleviated the hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis response and accordingly reversed the peripheral inflammation status. Moreover, the stress-induced structural and functional dysbiosis of the gut microbiome was improved by CCFM687, through increased alpha diversity and abundance of butyrate-producing bacteria, in conjunction with inhibition of pathogenic gene expression. In summary, these results indicate that supplementation of B. longum subsp. infantis strain CCFM687 may prevent the onset of depression from chronic stress, and RIN14B could serve as an efficient cell model for rapid screening of anti-depressive probiotics.

16.
Tech Hand Up Extrem Surg ; 23(4): 155-159, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31738737

RESUMO

Pedicled vascularized bone graft (VBG) is a useful method in treating the scaphoid fracture nonunion, especially when the avascular necrosis exists. Humpback deformity is an important issue that we have to correct it during the treatment. We describe a method by using combined wedge non-VBG to correct the nonunion deformity when treating scaphoid nonunion with pedicled VBG. The wedge bone graft was harvested just proximal to the 2,3 intercompartmental supraretinacular artery VBG and was used as an inlay at the volar site to correct the humpback deformity, whereas the VBG was set at the dorsal site for bone bridging and blood supply. We also present our results of 10 patients with scaphoid fracture nonunion and humpback deformity treated with this method. Bone healing was achieved and the lateral intrascaphoid angles could be improved in all the 10 patients. Functional outcomes, including the Visual Analog Pain Scale for pain during activity, grip strength, the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the modified Mayo Wrist Scores, were significantly improved.


Assuntos
Vasos Sanguíneos/transplante , Rádio (Anatomia)/transplante , Osso Escafoide/anormalidades , Osso Escafoide/cirurgia , Adolescente , Adulto , Transplante Ósseo/métodos , Osso Esponjoso/irrigação sanguínea , Osso Esponjoso/transplante , Osso Cortical/irrigação sanguínea , Osso Cortical/transplante , Feminino , Fraturas Ósseas/cirurgia , Fraturas não Consolidadas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Rádio (Anatomia)/irrigação sanguínea , Osso Escafoide/lesões , Adulto Jovem
17.
Sci Rep ; 9(1): 14613, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601849

RESUMO

Epidural fibrosis is an inevitable aspect of the postoperative healing process which is one of the causes of failed back surgery syndrome following spinal surgery. The aim of the present study was to examine the inhibitory effect of 1,4-butanediol diglycidyl ether-crosslinked hyaluronan (cHA) on spinal epidural fibrosis in a swine model. Epidural fibrosis was induced through conduction of hemi-laminotomy (L2 and L3) or laminectomy (L4 and L5), while L1 was assigned as the control group in six pigs. The cHA was applied to L3 and L5 surgical sites. MRI evaluation, histologic examination, expressions of matrix metalloproteinases (MMPs), and cytokines in scar tissue were assessed four months after surgery. cHA treatment significantly decreased the scar formation in both hemi-laminotomy and laminectomy sites. cHA also significantly increased MMP-3 and MMP-9 expression in scar tissue. Further, the epithelial-mesenchymal transition -related factors (transforming growth factor-ß and vimentin) were suppressed and the anti-inflammatory cytokines (CD44 and interleukin-6) were increasingly expressed in cHA-treated sites. The current study demonstrated that cHA may attenuate spinal epidural fibrosis formation after laminectomy surgery by enhancing the expression of MMPs and anti-inflammatory pathways.

18.
Cancer Gene Ther ; 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31543512

RESUMO

The present study discusses the expression and effect of the SOX17 gene in endometrioid adenocarcinoma. MTT assay is performed to determine the growth inhibition ratio of the DNA methyltransferase inhibitor 5-AZA for endometrial carcinoma cells, and the real-time fluorescence quantification PCR (qRT-PCR) was used to detect the mRNA expression of SOX17, ß-catenin, and CyclinD1 in endometrial carcinoma tissues before and after using 5-AZA to treat the endometrial carcinoma cell line. There were 30 cases on endometrioid adenocarcinoma tissues and 10 cases on normal endometrial tissues. The results revealed that the expression of SOX17 in endometrioid adenocarcinoma tissues was downregulated (P < 0.05), the expression of ß-catenin and CyclinD1 was upregulated (P < 0.05), and the expression of SOX17, CyclinD1, and ß-catenin was negatively correlated (r = -0.353, P > 0.05; R = -0.463, P < 0.05). The higher the histological grade and FIGO staging were, the lower the expression level of SOX17 was (P < 0.05). After HEC1A cells were treated by 5-AZA, the cell growth inhibition was most obvious (IC50 = 12.033) at 72 h, as determined by MTT assay. After cell treatment by 5-AZA, the genetic expression of SOX17 significantly increased, when compared with that before treatment (P < 0.05), while the genetic expression of ß-catenin and CyclinD1 significantly declined (P < 0.05). These results indicate that the expression level of SOX17 in endometrioid adenocarcinoma declined, and the upregulated expression level of SOX17 in cells inhibited the growth of tumor cells.

19.
Antioxidants (Basel) ; 8(9)2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31484360

RESUMO

Osteoarthritis (OA) is one of the most common types of arthritis in the elderly people. It has been known that chondrocyte apoptosis occurs in OA cartilage; however, the detailed molecular mechanism remains unclear. In the current study, we aimed to elucidate the role of double-stranded RNA-dependent protein kinase R (PKR) in the TNF-α-caused apoptosis in chondrocytes. Human articular chondrocytes were digested from cartilages of OA subjects who accepted arthroplastic knee surgery. Our results showed that phosphorylation of p38 MAPK was increased after TNF-α stimulation or PKR activation using poly (I:C), and TNF-α-induced p38 MAPK upregulation was inhibited by PKR inhibition, suggesting phosphor-p38 MAPK was regulated by PKR. Moreover, we found that PKR participated in the p53-dependent destruction of AKT following activation of p38 MAPK. The inhibition of AKT led to the reduced expression of PGC-1α, which resulted in mitochondrial dysfunction and increased oxidative stress. We showed that the reduction of oxidative stress using antioxidant Mito TEMPO lowered the TNF-α-induced caspase-3 activation and TUNEL-positive apoptotic cells. The diminished apoptotic response was also observed after repression of PKR/p38 MAPK/p53/AKT/PGC-1α signaling. Taken together, we demonstrated that the aberrant mitochondrial biogenesis and increased oxidative stress in chondrocytes after TNF-α stimulation were mediated by PKR, which may contribute to the chondrocyte apoptosis and cartilage degeneration in OA.

20.
Angew Chem Int Ed Engl ; 58(40): 14197-14201, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31385423

RESUMO

Bimetal-S-O composites have been rarely researched in electrochemical reduction of CO2 . Now, an amorphous Ag-Bi-S-O decorated Bi0 catalyst derived from Ag0.95 BiS0.75 O3.1 nanorods by electrochemical pre-treatment was used for catalyzing eCO2 RR, which exhibited a formate FE of 94.3 % with a formate partial current density of 12.52 mA cm-2 at an overpotential of only 450 mV. This superior performance was attributed to the attached amorphous Ag-Bi-S-O substance. S could be retained in the amorphous region after electrochemical pre-treatment only in samples derived from metal-S-O composites, and it would greatly enhance the formate selectivity by accelerating the dissociation of H2 O. The existence of Ag would increase the current density, resulting in a higher local pH, which made the role of S in activating H2 O more significantly and suppressed H2 evolution more effectively, thus endowing the catalyst with a higher formate FE at low overpotentials.

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