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1.
Brain Behav ; : e01562, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32027781

RESUMO

OBJECTIVES: To investigate the association of aspirin resistance (AR) with the plasma 4-hydroxynonenal (4-HNE) level and its impact on recurrent cerebral infarction (CI) in patients with acute cerebral infarction (ACI) who were receiving aspirin therapy. METHODS: One hundred and fifty-four ACI patients who previously received aspirin therapy (100 mg/day) were enrolled. Whole urine (for measuring 11dhTXB2 and creatinine) along with blood (for measuring the plasma 4-HNE level) were collected at least 7 days after the patients received aspirin. A cutoff of 1500 pg/mg of 11dhTXB2/ creatinine was used to determine AR. A follow-up period to monitor recurrence CI events was 1 year. In addition, blood testing was performed when the patients were first admitted to hospital. RESULTS: Forty-six of the 154 enrolled patients (29.9%) were found to be AR. No statistical difference in age, sex, hypertension, diabetes mellitus, coronary disease, smoking status, NIHSS score, TOAST classification, platelet count, thrombocytocrit, LDL-C, HDL-C, TG, and TC was found between the AR and aspirin-sensitive (AS) patients, but the plasma 4-HNE level was found to be higher in the AR patients than AS patients (p < .05). Multiple logistic regression analysis showed that the 4-HNE level was associated with a higher risk of AR (OR = 1.034; 95% CI = 1.011-1.058; p < .05). Moreover, 1-year follow-up showed that AR was more prevalent in patients with recurrent CI (26 (56.6%)) than those without (20/(43.5%)) (p < .001). CONCLUSIONS: The plasma 4-HNE level is strongly associated with AR and thus may be a factor contributing to AR. Patients with AR have a greater risk of recurrence CI.

2.
Structure ; 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32027819

RESUMO

Metazoan retromer (VPS26/VPS35/VPS29) associates with sorting nexins on endosomal tubules to sort proteins to the trans-Golgi network or plasma membrane. Mechanisms of metazoan retromer assembly remain undefined. We combine single-particle cryoelectron microscopy with biophysical methods to uncover multiple oligomer structures. 2D class averages reveal mammalian heterotrimers; dimers of trimers; tetramers of trimers; and flat chains. These species are further supported by biophysical solution studies. We provide reconstructions of all species, including key sub-structures (∼5 Å resolution). Local resolution variation suggests that heterotrimers and dimers adopt multiple conformations. Our structures identify a flexible, highly conserved electrostatic dimeric interface formed by VPS35 subunits. We generate structure-based mutants to disrupt this interface in vitro. Equivalent mutations in yeast demonstrate a mild cargo-sorting defect. Our data suggest the metazoan retromer is an adaptable and plastic scaffold that accommodates interactions with different sorting nexins to sort multiple cargoes from endosomes their final destinations.

3.
Gene ; 736: 144417, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32006593

RESUMO

Sphingosine 1-phosphate receptor 1 (S1PR1) plays a pivotal role in mediating trafficking and migration of immune cells. Previous reports also identify S1PR1 as an important susceptibility gene of asthma and other autoimmune disorders. However, little has been known about the regulatory mechanism of S1PR1 expression. Thus we systematically investigated the transcriptional regulation of S1PR1 in this study. Promoter activity of S1PR1 gene was carefully screened using series of pGL3-Basic reporter vectors, containing full length (range from transcription start site to upstream -1 kb region) or several truncated fragments of S1PR1 promoter. We identified an area (from -29 to -12 bp) of the S1PR1 promoter as the minimal promoter region. Bioinformatics prediction results showed that several transcription factors were recruited to these sites. EMSA and ChIP assays demonstrated the transcriptional factor STAT1 could bind to the region. We also found that the level of S1PR1 level was significantly reduced when STAT1 was knocked-down. Consistent with the reduction of S1PR1 caused by depletion of STAT1, overexpression of STAT1 resulted in up-regulation of S1PR1. In addition, both mRNA and protein levels of S1PR1 were increased when STAT1 was activated by IFN-γ, and decreased when STAT1 was inhibited by fludarabine. Besides, the levels of STAT1 and S1PR1 expression were positively correlated in peripheral blood leukocytes derived from 41 healthy individuals. Our study showed that transcription factor STAT1 could bind to upstream region of -29 bp to -12 bp of the S1PR1 promoter and stimulate the expression of S1PR1.

4.
Cytotherapy ; 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32063474

RESUMO

Gastrointestinal (GI) tract is the most common site of extranodal involvement in non-Hodgkin lymphoma. Life-threatening complications of GI may occur because of tumor or chemotherapy. Chimeric antigen receptor (CAR) T-cell therapy has been successfully used to treat refractory/relapse B-cell lymphoma, however, little is known about the efficacy and safety of CAR-T cell therapy for GI lymphoma. Here, we reported the efficacy and safety of CAR-T cell therapy in 14 patients with relapsed/refractory aggressive B-cell lymphoma involving the GI tract. After a sequential anti-CD22/anti-CD19 CAR-T therapy, 10 patients achieved an objective response, and seven patients achieved a complete response. CAR transgene and B-cell aplasia persisted in the majority of patients irrespective of response status. Six patients with partial response or stable disease developed progressive disease; two patients lost target antigens. Cytokine release syndrome (CRS) and GI adverse events were generally mild and manageable. The most common GI adverse events were diarrhea (4/14), vomiting (3/14) and hemorrhage (2/14). No perforation occurred during follow-up. Infection is a severe complication in GI lymphoma. Two patients were infected with bacteria that are able to colonize at GI; one died of sepsis early after CAR-T cells infusion. In conclusion, our study showed promising efficacy and safety of CAR-T cell therapy in refractory/relapsed B-cell lymphoma involving the GI tract. However, the characteristics of CAR-T-related infection in GI lymphoma should be further clarified to prevent and control infection.

5.
Int Immunopharmacol ; 81: 106258, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32044660

RESUMO

While imiquimod (IMQ) has been widely used in dermatology, its side effect manifested as dermatitis couldn't be ignored. However, the underlying mechanism has not been fully understood. Considering the clinical features of IMQ-related dermatitis similar to pseudo-allergic reaction and the presence of large numbers of mast cell in tissues treated with IMQ, the possibility that IMQ-related dermatitis mediated by mast cell-specific Mas-related G protein-coupled receptor X2 (MRGPRX2) should be addressed. To investigate the role of MRGPRX2 in vivo, MrgprB2, the mice homology of human MRGPRX2, was detected in IMQ-induced dermatitis mouse model. Histopathological changes including mast cell degranulation and footpad swelling were assayed in wild-type and MrgprB2-/- mice. The results showed that IMQ application induced dermatitis and footpad swelling with inflammatory cells infiltration plus mast cell activation in the skin of wild-type mice but reduced significantly in MrgprB2-/- mice. Further, compared to wild-type mice, serum histamine and inflammatory cytokine levels were compromised in MrgprB2-/- mice treated with IMQ, while the serum IgE level didn't change significantly. In vitro studies, levels of mediators released from murine peritoneal mast cells (MPMCs) after IMQ treatment were increased in a dose-dependent manner, which were much mild in MPMCs from MrgprB2-/- mice. Intracellular Ca2+ concentration was increased in a dose dependent manner after IMQ treatment both in MrgprB2-HEK293 and MRGPRX2-HEK293 cells. Moreover, ß-hexosaminidase released after IMQ treatment was blocked by siRNA directed at the MRGPRX2 receptor in LAD2 cells. In summary, MrgprB2 /MRGPRX2 mediate mast cell activation and participate in IMQ-related dermatitis.

6.
Ecotoxicol Environ Saf ; 191: 110247, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32004943

RESUMO

2,4-diaminobutyric acid (DAB), a newly identified algal toxins in water, pose a great threat to human health. DAB may react with chlorine or chloramine to produce CX3R-type disinfection by-products (DBPs) during water treatment processes. This study mainly investigated the formation and speciation of DBPs from chlor(am)ination of DAB. The results revealed that haloacetic acids (HAAs), trihalomethanes (THMs) and haloacetonitriles (HANs) were the main kinds of CX3R-type DBPs generated from DAB during chlor(am)ination, of which dichloroacetic acid yielded the highest. The formation and total toxicity of four CX3R-type DBPs from DAB during chloramination was significantly lower than that during chlorination at each Cl2:N molar ratio. However, more formation of Br-THMs and I-THMs were observed during chloramination in the presence of Br-/I-. Futhermore, the effects of chlor(am)ine dosage, solution pH, reaction time, and the concentration of Br- and I- on the formation and speciation of CX3R-type DBPs were also evaluated during chlor(am)ination. The plausible formation pathways of CX3R-type DBPs from DAB were proposed and verified by theoretical calculation. The quantum chemistry calculations indicate that 1N in DAB and 8N in 2,4-diaminochlorobutyric acid (C4H9O2N2Cl) were more likely to be attacked by electrophiles, supporting the proposed pathway schemes.

7.
Diabetes Res Clin Pract ; 159: 107999, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31904443

RESUMO

OBJECTIVE: To study the changes in glucose and lipid metabolism indexes and the condition of early atherosclerosis in patients with diabetes with and without obstructive sleep apnea syndrome (OSAS). METHODS: Patients with type 2 diabetes mellitus (DM) aged 32-50 years who did not have significant complications were included. A total of 42 patients with DM with OSAS and 46 patients with DM without OSAS were chosen according to their sleep monitoring indexes. Height and weight were measured, and fasting blood glucose, postprandial blood glucose, endothelin (ET), nitric oxide (NO) and lipid profile were tested. Then, all the subjects were subjected to the pulse wave velocity (PWV) test. RESULTS: The levels of glycated haemoglobin and triglycerides were significantly higher in patients with DM with OSAS than those in patients with DM without OSAS. ET, NO and PWV changed significantly. CONCLUSION: Patients with diabetes with OSAS are more likely to have complications related to arteriosclerosis and aggravation of glycolipid metabolism disorder. Early intervention is recommended.

8.
Phytomedicine ; 67: 153154, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31926475

RESUMO

BACKGROUND: Kanglaite injection (KLT) is a broad-spectrum anti-tumor drug, which is extracted from the seeds of the Chinese medicinal herb Coix lacryma-jobi, and has been widely used for the treatment of advanced lung cancer. PURPOSE: To evaluate the combined effects of Kanglaite injection plus platinum-based chemotherapy (PBC) on patients with stage III/IV non-small cell lung cancer (NSCLC). STUDY DESIGN: A systematic review and meta-analysis of randomized clinical trials (RCTs). MATERIALS AND METHODS: Twelve databases were searched from their inceptions until July 05, 2019. All the RCTs comparing the efficacy and safety of Kanglaite injection plus PBC versus PBC alone were selected. Analyses were performed using Review Manager 5.3, Comprehensive Meta-Analysis 3.0 and Trial Sequential Analysis (TSA). Disease control rate (DCR) was defined as the primary endpoint, objective response rate (ORR), survival rate, quality of life (QOL), cellular immunity function, and toxicities were defined as the secondary endpoints. RESULTS: Twenty-seven RCTs recruiting 2,243 patients with stage III/IV NSCLC were included. The results showed that, compared with PBC alone, Kanglaite injection plus PBC improved DCR (RR = 1.20, 95% CI 1.15-1.26, p < 0.00001), ORR (RR = 1.45, 95% CI 1.31-1.60, p < 0.00001), 1-year survival rate (RR = 1.20, 95% CI 1.02-1.43, p = 0.03), QOL (RR = 1.32, 95% CI 1.25-1.40, p < 0.00001), CD4+T cells (WMD = 4.86, 95% CI 4.00-5.73, p < 0.00001), CD4+/CD8+ ratio (WMD = 0.19, 95% CI 0.07-0.31, p < 0.002), and reduced severe toxicities by 59% (RR = 0.41, 95% CI 0.33-0.51, p < 0.00001). Most results were robust and the quality of evidence was from moderate to low. CONCLUSIONS: Kanglaite injection in combination with PBC showed significantly higher efficacy than PBC alone in the treatment of stage III/IV NSCLC. Moreover, the combination therapy can improve cellular immunity and attenuate the severe toxicities caused by chemotherapy. However, high-quality RCTs are warranted to further assess the effects of the combined therapy.

9.
Nat Commun ; 11(1): 423, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31969570

RESUMO

N-Methyl-D-aspartate receptors (NMDARs) play critical roles in the central nervous system. Their heterotetrameric composition generates subtypes with distinct functional properties and spatio-temporal distribution in the brain, raising the possibility for subtype-specific targeting by pharmacological means for treatment of neurological diseases. While specific compounds for GluN2A and GluN2B-containing NMDARs are well established, those that target GluN2C and GluN2D are currently underdeveloped with low potency and uncharacterized binding modes. Here, using electrophysiology and X-ray crystallography, we show that UBP791 ((2S*,3R*)-1-(7-(2-carboxyethyl)phenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid) inhibits GluN2C/2D with 40-fold selectivity over GluN2A-containing receptors, and that a methionine and a lysine residue in the ligand binding pocket (GluN2D-Met763/Lys766, GluN2C-Met736/Lys739) are the critical molecular elements for the subtype-specific binding. These findings led to development of UBP1700 ((2S*,3R*)-1-(7-(2-carboxyvinyl)phenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid) which shows over 50-fold GluN2C/2D-selectivity over GluN2A with potencies in the low nanomolar range. Our study shows that the L-glutamate binding site can be targeted for GluN2C/2D-specific inhibition.

10.
PLoS One ; 15(1): e0227021, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31914167

RESUMO

The amplitude of low-frequency fluctuation (ALFF) measures resting-state functional magnetic resonance imaging (RS-fMRI) signal of each voxel. However, the unit of blood oxygenation level-dependent (BOLD) signal is arbitrary and hence ALFF is sensitive to the scale of raw signal. A well-accepted standardization procedure is to divide each voxel's ALFF by the global mean ALFF, named mALFF. Although fractional ALFF (fALFF), a ratio of the ALFF to the total amplitude within the full frequency band, offers possible solution of the standardization, it actually mixes with the fluctuation power within the full frequency band and thus cannot reveal the true amplitude characteristics of a given frequency band. The current study borrowed the percent signal change in task fMRI studies and proposed percent amplitude of fluctuation (PerAF) for RS-fMRI. We firstly applied PerAF and mPerAF (i.e., divided by global mean PerAF) to eyes open (EO) vs. eyes closed (EC) RS-fMRI data. PerAF and mPerAF yielded prominently difference between EO and EC, being well consistent with previous studies. We secondly performed test-retest reliability analysis and found that (PerAF ≈ mPerAF ≈ mALFF) > (fALFF ≈ mfALFF). Head motion regression (Friston-24) increased the reliability of PerAF, but decreased all other metrics (e.g. mPerAF, mALFF, fALFF, and mfALFF). The above results suggest that mPerAF is a valid, more reliable, more straightforward, and hence a promising metric for voxel-level RS-fMRI studies. Future study could use both PerAF and mPerAF metrics. For prompting future application of PerAF, we implemented PerAF in a new version of REST package named RESTplus.

11.
Artigo em Inglês | MEDLINE | ID: mdl-31916926

RESUMO

Background: Fat grafting is a standard method for soft augmentation. However, occasionally Mycobacterium abscessus infection can be seen secondary to fat grafting. The aim of this study was to report experience with and propose standard treatment. Patients and Methods: From 2006 to 2018, 12 women who had received fat grafting for facial soft augmentation in different Chinese private clinics were reviewed. Results: The patients presented with local swelling and skin ulceration. They patients received primary infusion of antibiotic agents; however, the results were poor. After being admitted to our hospital, cultures were taken and sent to the specialized examination center. Mycobacterium abscessus was diagnosed in all of the patients. According to drug sensitivity results, targeted antibiotic agent treatment was implemented for 12 months. Local proper conservative debridement was conducted as needed. When the patients were discharged from the hospital, they were advised to continual oral medication for six months. After three to nine years of follow-up, no recurrence was found. On the basis of this, a corresponding standard treatment was proposed. Conclusions: Mycobacterium abscessus infection after fat grafting should be diagnosed and treated accurately. Our experience and proposed treatment may be beneficial.

12.
Oncol Res ; 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31987067

RESUMO

Hypopharyngeal squamous cell carcinoma (HSCC) remains one of the most lethal malignancies in the head and neck. Long noncoding RNA (lncRNA) HOXA11-AS is proven to function as an oncogene and a therapeutic target in various tumors. Our previous study and the others have demonstrated that HOXA11-AS is one of the most up-regulated lncRNAs in HSCC. However, the role of HOXA11-AS in HSCC has not yet been identified. The current study demonstrated that the expression of HOXA11-AS was significantly up-regulated in HSCC tumors and positively associated with lymph node metastasis. Moreover, functional experiments revealed that HOXA11-AS knockdown suppressed the proliferation and migration potential in FaDu cells. Furthermore, luciferase reporter gene assay combined with cellular functional experiments demonstrated that HOXA11-AS functioned as a molecular sponge for miR-155, and inhibition of miR-155 attenuated the suppressive effect of HOXA11-AS knockdown on the aggressive phenotype in HSCC. This study identifies a tumor promoting role of HOXA11-AS in HSCC and suggests HOXA11-AS might be a potential diagnostic and therapeutic target for HSCC.

13.
Neurosci Bull ; 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31989424

RESUMO

Chemical stimulation of the kidney increases sympathetic activity and blood pressure in rats. The hypothalamic paraventricular nucleus (PVN) is important in mediating the excitatory renal reflex (ERR). In this study, we examined the role of molecular signaling in the PVN in mediating the capsaicin-induced ERR and sympathetic activation. Bilateral PVN microinjections were performed in rats under anesthesia. The ERR was elicited by infusion of capsaicin into the cortico-medullary border of the right kidney. The reflex was evaluated as the capsaicin-induced changes in left renal sympathetic nerve activity and mean arterial pressure. Blockade of angiotensin type 1 receptors with losartan or inhibition of angiotensin-converting enzyme with captopril in the PVN abolished the capsaicin-induced ERR. Renal infusion of capsaicin significantly increased NAD(P)H oxidase activity and superoxide anion production in the PVN, which were prevented by ipsilateral renal denervation or microinjection of losartan into the PVN. Furthermore, either scavenging of superoxide anions or inhibition of NAD(P)H oxidase in the PVN abolished the capsaicin-induced ERR. We conclude that the ERR induced by renal infusion of capsaicin is mediated by angiotensin type 1 receptor-related NAD(P)H oxidase activation and superoxide anion production within the PVN.

14.
Phytother Res ; 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31989711

RESUMO

Mast cells play an important role in inflammatory and allergic diseases. MAS-related G protein-coupled receptor X2 (MRGPRX2) is a novel G protein-coupled receptor in mast cells that mediates drug-induced anaphylactoid reactions. Piperine has been reported to have anti-inflammatory and anti-allergic pharmacological activities. However, whether the pharmacological effects are regulated by MRGPRX2 has not yet been reported. The purpose of this study was to assess the anti-anaphylactoid effect of Piperine and to explore its potential mechanism. The anti-anaphylactoid effect of Piperine was assessed by an in vivo mouse hindpaw extravasation model. Mast cell intracellular calcium mobilization was measured by a calcium imaging assay. An enzyme immunoassay was used to evaluate the release of pro-inflammatory factors from stimulated mast cells. Activated mast cell related signals were assessed by western blot. A cell membrane chromatography assay was used to determine the binding characteristics of Piperine and MRGPRX2. The results showed that Piperine suppressed mast cell intracellular Ca2+ mobilization, inhibited cytokines and chemokines release, and down-regulated the phosphorylation level of phospholipase Cγ1, protein kinase C, inositol 1,4,5-triphate receptor, P38, protein kinase B, and ERK. Meanwhile, Piperine can bind to MRGPRX2 as a specific antagonist. Hence, Piperine can be served as a novel therapeutic drug candidate for MRGPRX2-mediated anaphylactoid reactions.

15.
J Phys Chem Lett ; 11(3): 762-766, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31935326

RESUMO

The upper limit in LED quantum efficiency from conventional closed-shell molecules is 25% as dictated by singlet and triplet spin statistics. Spin-doublet organic molecules are attractive candidates to exceed this limit, thanks to their 100% theoretical quantum efficiency in radiative recombination. However, examples of stable spin-doublet molecules in the solid state are rare. Here we show broad-band near-infrared emission in the columnar π-π stacked tetrathiafulvalene (TTF) in a metal organic framework (MOF) single crystal. The broad emission is similar to known TTF+• doublet emission and is stabilized in the MOF crystal. This interpretation is supported by the observation of enhanced PL emission following UV oxidation of the MOF crystal to increase the doublet concentration. The findings suggest tetrathiafulvalene-based MOFs as promising materials for near-IR light emission and the MOF structure may be a general strategy to stabilize radical cation species in the solid state.

16.
J Proteome Res ; 19(2): 864-872, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31917576

RESUMO

Ankylosing spondylitis (AS) is a systemic, chronic, and inflammatory rheumatic disease that affects 0.2% of the population. Current diagnostic criteria for disease activity rely on subjective Bath Ankylosing Spondylitis Disease Activity Index scores. Here, we aimed to discover a panel of serum protein biomarkers. First, tandem mass tag (TMT)-based quantitative proteomics was applied to identify differential proteins between 15 pooled active AS and 60 pooled healthy subjects. Second, cohort 1 of 328 humans, including 138 active AS and 190 healthy subjects from two independent centers, was used for biomarker discovery and validation. Finally, biomarker panels were applied to differentiate among active AS, stable AS, and healthy subjects from cohort 2, which enrolled 28 patients with stable AS, 26 with active AS, and 28 healthy subjects. From the proteomics study, a total of 762 proteins were identified and 46 proteins were up-regulated and 59 proteins were down-regulated in active AS patients compared to those in healthy persons. Among them, C-reactive protein (CRP), complement factor H-related protein 3 (CFHR3), α-1-acid glycoprotein 2 (ORM2), serum amyloid A1 (SAA1), fibrinogen γ (FG-γ), and fibrinogen ß (FG-ß) were the most significantly up-regulated inflammation-related proteins and S100A8, fatty acid-binding protein 5 (FABP5), and thrombospondin 1 (THBS1) were the most significantly down-regulated inflammation-related proteins. From the cohort 1 study, the best panel for the diagnosis of active AS vs healthy subjects is the combination of CRP and SAA1. The area under the receiver operating characteristic (ROC) curve was nearly 0.900, the sensitivity was 0.970%, and the specificity was 0.805% at a 95% confidence interval from 0.811 to 0.977. Using 0.387 as the cutoff value, the predictive values reached 92.00% in the internal validation set (62 with active AS vs 114 healthy subjects) and 97.50% in the external validation phase (40 with active AS vs 40 healthy subjects). From the cohort 2 study, a panel of CRP and SAA1 can differentiate well among active AS, stable AS, and healthy subjects. For active AS vs stable AS, the area under the ROC curve was 0.951, the sensitivity was 96.43%, the specificity was 88.46% at a 95% confidence interval from 0.891 to 1, and the coincidence rate was 92.30%. For stable AS vs healthy humans, the area under the ROC curve was 0.908, the sensitivity was 89.29%, the specificity was 78.57% at a 95% confidence interval from 0.836 to 0.980, and the coincidence rate was 83.93%. For active AS vs healthy subjects, the predictive value was 94.44%. The results indicated that the CRP and SAA1 combination can potentially diagnose disease status, especially for active or stable AS, which will be conducive to treatment recommendation for patients with AS.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31968167

RESUMO

In this work, PtNi/GC octahedral nanocrystal catalysts are prepared using graphitized carbon (GC) to solve the problems of cathode catalysts in catalytic performance and proton-exchange membrane fuel cell application. The as-prepared supported catalysts exhibit well-crystallized octahedral morphologies and graphite layer structures with high corrosion resistance. Their mass activities and specific activities are 5 and 7 times higher than those of the commercial Pt/C. The sample with the best performance shows the cell voltage at 1000 mA cm-2 of 0.672 V and maximum power density of 817.6 mW cm-2 in the single-cell test, which are increased by 23 mV and 13.2 mW cm-2 compared to the control. Especially after a high potential test, the above two parameters of this sample are reduced by only 5.6 and 8.4%, which are significantly lower than the attenuation of the control fabricated using Vulcan XC-72 carbon black. The work reveals that the GC-supported PtNi octahedral catalysts can give better consideration to the improvement of electrochemical and single-cell performances.

18.
Nanotechnology ; 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000153

RESUMO

Microwave approach has been widely used for synthesis of fluorescent carbon dots (CDs) due to their advantages of short reaction time and homogeneous heating. By far, it is still difficult to synthesize red ligth-emitting CDs (R-CDs) via the microwave-assisted method at atmospheric pressure. Herein, we reported a solvent-controlled synthesis of R-CDs using domestic microwave. As a result, for an ammonium citrate tribasic, formamide and glycerol blend reaction solvent, the R-CDs with emission peak of 622 nm were achieved and exhibited a photoluminescence (PL) quantum yield of 37.4% and excitation-independent PL emission spectrum. During the formation process of R-CDs, glycerol and formamide not only promote the carbonization of ammonium citrate tribasic, but also can enhance the crystalline nature of CDs. Fianlly, the warm white light-emitting diode (WLED) with a high color rendering index (CRI) of 90.9 and Commission International de L'Echairage (CIE) coordinates of (0.344, 0.333) was realized by combing conventional yellow YAG:Ce phosphor and R-CDs/mesoporous silica (MPS) composites with a blue chip. This result demonstrates a low-cost R-CD synthetic method for potential substitution for red phosphor materials in solid-state lighting applications.

19.
Chem Commun (Camb) ; 56(12): 1823-1826, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31950119

RESUMO

A binder-free electrode consisting of Pd clusters and vanadium oxide (VO) has been prepared via gas-phase-cluster beam deposition on carbon cloth. The Pd clusters largely improve the stability of the VO-Pd-based electrode, which can be reversibly and continuously cycled for more than 120 cycles in a Li-O2 based battery.

20.
Neurosci Lett ; 715: 134674, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31809803

RESUMO

Medial vestibular nucleus (MVN) neurons are involved in the regulation of eye movements to endure the stability of the image during head movement, and play a critical role in plasticity of the vestibulo-ocular reflex (VOR) during the juvenile period. We have previously shown that the long-term depression (LTD) of synaptic transmission was induced by high frequency stimulation (HFS) and blocked by N-methyl-D-aspartate (NMDA) receptor antagonist D-APV at the vestibular afferent synapses of type-B MVN neurons. In the present study, we used whole-cell patch-clamp recordings in vitro to investigate the subunit composition of these NMDA receptors in the induction of LTD in MVN slices from postnatal 13-16 day rats. We found that LTD induced in type-B neurons of the rat MVN with HFS was blocked by Ro 25-6981, a specific antagonist for GluN2B-containing NMDA receptors. Moreover, the other selective GluN2B-containing NMDA receptor antagonist (ifenprodil) also prevented the induction of LTD. However, bath application of the GluN2A-containing NMDA receptor antagonists (Zn2+ and TCN 201) had no influence on the induction of LTD. Similar results were obtained by exogenously applied two GluN2C/GluN2D-preferring NMDA receptor antagonists (PPDA and UBP 141). Furthermore, presynaptic NMDA receptor subunits are not necessary for vestibular LTD. These results suggest that the induction of LTD by HFS in vestibular afferent synapses of type-B MVN neurons requires postsynaptic GluN2B-containing NMDA receptors, but not GluN2A-containing NMDA receptors or GluN2C/GluN2D-containing NMDA receptors.

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