Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
BMC Cancer ; 20(1): 525, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503466

RESUMO

BACKGROUND: Previous researches have reported that tripartite motif-containing 44 (TRIM44) is related to the prognosis of multiple human tumors. This study was designed to systematically assess the prognostic value of TRIM44 in human malignancies and summarize its possible tumor-related mechanisms. METHODS: The available databases were searched for eligible studies that evaluated the clinicopathological and prognostic roles of TRIM44 in patients with malignancies. The hazard ratios (HR) and odds ratios (OR) were combined to assess the predictive role of TRIM44 using Stata/SE 14.1 software. RESULTS: A total of 1740 patients from thirteen original studies were finally included in this study. The results of the combined analysis showed that over-expression of TRIM44 protein was significantly correlated with shorter overall survival (OS) (HR = 1.94, 95% CI: 1.60-2.35) and worse disease-free survival (DFS) (HR = 2.13, 95% CI: 1.24-3.65) in cancer patients. Additionally, the combined ORs indicated that elevated expression level of TRIM44 protein was significantly associated with lymph node metastasis (OR = 2.69, 95% CI: 1.71-4.24), distant metastasis (OR = 10.35, 95% CI: 1.01-106.24), poor tumor differentiation (OR = 1.78, 95% CI: 1.03-3.09), increased depth of tumor invasion (OR = 2.72, 95% CI: 1.73-4.30), advanced clinical stage (OR = 2.75, 95% CI: 2.04-3.71), and recurrence (OR = 2.30, 95% CI: 1.34-3.95). Furthermore, analysis results using Gene Expression Profiling Interactive Analysis (GEPIA) showed that the expression level of TRIM44 mRNA was higher in most tumor tissues than in the corresponding normal tissues, and the relationship between TRIM44 mRNA level and prognosis in various malignant tumors also explored in GEPIA and OS analysis webservers. CONCLUSIONS: TRIM44 may serve as a valuable prognostic biomarker and a potential therapeutic target for patients with malignancies.


Assuntos
Antineoplásicos/farmacologia , Biomarcadores Tumorais/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Recidiva Local de Neoplasia/diagnóstico , Neoplasias/mortalidade , Proteínas com Motivo Tripartido/metabolismo , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/antagonistas & inibidores , Diferenciação Celular , Intervalo Livre de Doença , Estudos de Viabilidade , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Invasividade Neoplásica , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/prevenção & controle , Estadiamento de Neoplasias , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Valor Preditivo dos Testes , Prognóstico , Proteínas com Motivo Tripartido/antagonistas & inibidores
2.
Respir Res ; 20(1): 202, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31481083

RESUMO

BACKGROUND: Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer death in the world, and has a relatively low survival rate. Long non-coding RNAs (lncRNAs) have been demonstrated to modulate cancer progression through a variety of molecular mechanisms. We sought to investigate the role and potential mechanism of MYC-induced long non-coding RNA (MINCR) in NSCLC. METHODS: Expression levels of MINCR was first identified using The Cancer Genome Atlas (TCGA), further confirmed with specimens from 29 NSCLC patients and three cell lines using qRT-PCR. Overexpression and knockdown of MINCR were performed in NSCLC cell lines through MINCR overexpression vectors and synthesized siRNAs, respectively. The roles of MINCR in NSCLC cell lines, such as cell proliferation, cell cycle arrest, and apoptosis, were identified by MTT, flow cytometry, and Western blot. The modulation of MINCR-regulated genes, including c-Myc and its downstream effectors, as well as apoptosis-associated genes, was analyzed using Western blot. RESULTS: MINCR expression was increased in NSCLC patients from TCGA datasets, and was also significantly increased in our collected specimens from NSCLC patients and NSCLC cell lines. Knocking down of MINCR greatly inhibited the growth of NSCLC cell lines PC9 and A549. In addition, silencing of MINCR induced cell cycle arrest and apoptosis. Furthermore, silencing of MINCR reduced the expression levels of oncogene c-Myc and its downstream cyclin A, cyclin D, CD4, and CDK2, as well as apoptosis-associated Bcl-2, while significantly increased the expression levels of cleaved PARP-1. In the meantime, overexpression of MINCR remarkably enhanced cell proliferation of PC9 cells and activated c-Myc and its downstream effectors. CONCLUSION: MINCR exerted inhibitory effects on the cell cycle arrest and apoptosis of NSCLC cells by activating c-Myc and its downstream effectors, suggesting that this lncRNA could be used as a potential therapeutic target for the treatment of NSCLC.


Assuntos
Apoptose/fisiologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Pontos de Checagem do Ciclo Celular/fisiologia , Neoplasias Pulmonares/metabolismo , RNA Longo não Codificante/biossíntese , Células A549 , Idoso , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , RNA Longo não Codificante/genética
3.
J Dairy Res ; 84(1): 23-26, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28252356

RESUMO

The study reported in this Research Communication was carried out to examine how parity and milking time affected donkey milk yield under a typical Chinese production system. Eighteen Jiangyue breed donkeys with good health condition, aged between 6 and 9 years, and with parities 3 and 4, were selected. Milk production was measured commencing from the fourth week post-foaling, with a total data collection of 170 d in milk (lactation length). Mean milk yield of the donkeys used in this study was 3·0 kg/donkey/d. Results showed milk yield decreased with days in milk from 3·3 kg/donkey/d at the start of the study, to 2·2 kg/donkey/d by the end of the 170 d. Parity 3 donkeys produced 22% more milk than parity 4 donkeys (3·3 kg/donkey/d vs 2·7 kg/donkey/d). The information provided by this study should aid producers in estimating the expected milk yields from individual donkey, and better predict milk yield over the course of a production cycle.


Assuntos
Indústria de Laticínios/métodos , Equidae/fisiologia , Lactação/fisiologia , Paridade/fisiologia , Animais , China , Dieta/veterinária , Feminino , Leite , Gravidez , Estações do Ano , Fatores de Tempo
4.
J Am Chem Soc ; 136(23): 8374-86, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24826843

RESUMO

Periodic density functional theory (DFT) calculations and microkinetic modeling are used to investigate the electrochemical oxidation of H2 fuel on the (001) surface of Sr2Fe1.5Mo0.5O6 (SFMO) perovskite under anodic solid oxide fuel cell conditions. Three surface models with different Fe/Mo ratios in the topmost layer-identified by ab initio thermodynamic analysis-are used to investigate the H2 oxidation mechanism. A microkinetic analysis that considers the effects of anode bias potential suggests that a higher Mo concentration in the surface increases the activity of the surface toward H2 oxidation. At operating voltage and anodic SOFC conditions, the model predicts that water desorption is rate-controlling and that stabilizing the oxygen vacancy structure increases the overall rate for H2 oxidation. Although we find that Mo plays a crucial role in improving catalytic activity of SFMO, under fuel cell operating conditions, the Mo content in the surface layer tends to be very low. On the basis of these results and in agreement with previous experimental observations, a strategy for improving the overall electrochemical performance of SFMO is increasing the Mo content or adding small amounts of an active transition metal, such as Ni, to the surface to lower the oxygen vacancy formation energy of the SFMO surface.

5.
J Nanosci Nanotechnol ; 11(3): 1923-8, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21449329

RESUMO

Cu, Mn and Ag nanoparticles are loaded on nanostructured mesoporous CeO2 as catalysts for CO oxidation. The Cu/CeO2 catalyst exhibits an obvious deactivation after the stability test at 95 degrees C for 60 h. This is caused by carbon deposition as confirmed by FTIR spectroscopy, Raman spectroscopy and thermogravimetry-differential scanning calorimetry-mass spectroscopy (TG-DSC-MS) analysis. It is found that the Cu-Mn or Cu-Ag binary metal catalysts supported on the nanostructured CeO2 exhibit much improved activity and stability in CO oxidation. In ease case, carbon deposition is absent in the similar stability test, due to enhanced oxygen adsorption property.


Assuntos
Monóxido de Carbono/química , Cério/química , Metais/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Catálise , Teste de Materiais , Oxirredução , Porosidade
6.
Aging (Albany NY) ; 13(14): 18482-18497, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34319912

RESUMO

Proliferation and metastasis are important malignant features of pancreatic cancer (PC), but the underlying molecular mechanism is unclear. ZC3HAV1, a PARP family member of proteins-enzymes, has been considered to play a significant part in a variety of biological processes. Nonetheless, the functions of ZC3HAV1 in developing PC are still unknown. This research aims to explore the biological function and the expression of ZC3HAV1 shown in PC. In our study, PCR analysis suggested that ZC3HAV1 was expressed at a high level in PC tissues and cell lines, and high ZC3HAV1 expression was remarkably related to poor prognosis. The functional assays indicated that upregulated ZC3HAV1 accelerated PC cell proliferation along with colony formation capacities in vitro. Subsequently, ZC3HAV1 could upregulate cyclin D1 and CDK2 and also promote G1/S transition in cells of PC. What's more, we also discovered that ZC3HAV1 promotes the migration and the invasion of PC cells. It upregulates the expression of EMT (epithelial-mesenchymal transition) relevant markers. Conversely, the functional assays showed that ZC3HAV1 knockdown significantly reduced tumorigenesis. Using bioinformatics analysis and immunoprecipitation assays we found that ZC3HAV1 could directly bind to KRAS and positively regulate its expression. Furthermore, ZC3HAV1 overexpression activated MAPK signaling by increasing p-ERK levels. Conversely, knockdown of KRAS attenuated ZC3HAV1-mediated promotion of proliferation and invasion in cells of PC. The result indicated that ZC3HAV1 was in relation to poor prognosis and accelerated the proliferation and metastasis of PC cells by regulation of KRAS. Our research may offer brand-new evidence to diagnose and treat PC in clinic.


Assuntos
Proliferação de Células , Transição Epitelial-Mesenquimal , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Knockout , Camundongos Nus , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas de Ligação a RNA/genética , Células Tumorais Cultivadas , Regulação para Cima , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Rev Sci Instrum ; 92(4): 043539, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243464

RESUMO

The supersonic molecular beam injection (SMBI) technique is widely used in magnetic fusion devices for plasma fueling and active control of particles. The beam flow formed by the SMBI system is directly visualized by a newly established schlieren diagnostic system on the SMBI testing platform. This schlieren system could provide a 2D density distribution of the beam with the sub-mm spatial resolution by detecting the change in the refractive index of the medium caused by the SMBI in the low-pressure vacuum chamber. The structure and the divergence angle of the supersonic molecular beam for fusion plasma fueling are first measured. Additionally, the density profile of the supersonic molecular beam is reconstructed from the measured light intensity by the schlieren system. The experimental comparison between the standard nozzle and the optimized nozzle of the SMBI system shows the great potential of the diagnostic system in optimizing the beam characteristics.

8.
Anim Biosci ; 34(2): 192-197, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32777909

RESUMO

OBJECTIVE: The present study evaluated the preservation of ram semen at 0°C using soybean lecithin with a Tris-fructose extender. METHODS: Semen was collected by artificial vagina ejaculation from six rams with proven fertility. High quality ejaculates were diluted by soybean lecithin (0.25%, 0.5%, 0.75%, 1.0%, 1.25%) using Tris-fructose extender and control (Tris-fructose egg yolk extender), respectively. The ejaculates were diluted to a concentration of 5×108 sperm/mL, followed by cooling to 0°C in 90 min and maintaining the temperature for 12 days. The diluted semen samples were examined and recorded for sperm progressive motility, acrosome integrity at 0, 24, 72, 144, 216, 288 h, respectively. Two hundred and twenty-three ewes were inseminated for 216 h with optimal soybean lecithin concentrated semen or control via trans-cervical insemination. RESULTS: The results showed that there were no differences in sperm progressive motility at 0, 24, 72, and 144 h (p>0.05). After 216 h, the sperm progressive motility in the control group and 0.5% concentration groups was significantly higher when compared to 0.25% concentration (p<0.05). The 0.5% concentration group demonstrated the highest survival rate and had no difference with the control group (p>0.05). At 216 h, the sperm progressive motility of all groups was still above 50%. The acrosome integrity of all groups was decreased with prolongation of storage time, but there was no difference at each time point (p>0.05). There was no significant difference in the lambing rate and pregnancy rate between the 0.5% concentration group and the control group (p>0.05). CONCLUSION: These results suggest that ram sperm is capable of fertilization after preservation at 0°C with 0.5% of soybean lecithin in Tris-based extender substituted for egg yolk and produce normal offspring after insemination.

9.
Cancer Manag Res ; 11: 3381-3393, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31114374

RESUMO

Background and aim: Serum fibrinogen and albumin are two important factors in systemic inflammation and these two factors are related to tumor progression. This study aimed to comprehensively reveal the prognostic value of the ratio of fibrinogen and albumin in malignant tumors. Methods: We systematically searched relevant studies in PubMed, Web of Science and Embase up to November 21, 2018. Hazard ratios (HRs) or odds ratio (ORs) for overall survival (OS)/disease-free survival (DFS), as well as relevant clinical data, were collected for analysis; all data analyses were performed by using STATA/SE 14. Results: Twelve cohort studies were included in this meta-analysis, with a total of 5,088 cases including 9 different kinds of tumors recruited. The pooled results showed that high albumin/fibrinogen ratio (FAR) and low fibrinogen/albumin ratio (AFR) were significantly associated with poor OS (HR=1.50, 95% CI: 1.30-1.70). Subgroup analyses for OS were also performed based on the disease type, detection method, follow-up time and treatment. Similarly, high FAR or low AFR indicated a worse DFS in cancer patients (HR=1.86; 95% CI: 1.41-2.31). In addition, high FAR or low AFR was statistically significant in relation to deeper tumor infiltration (OR=2.81, 95%CI: 1.67-4.72), positive lymph node metastasis (OR=1.57, 95%CI: 1.23-2.02) and distant metastasis (OR=2.30, 95% CI: 1.36-3.89) as well as advanced clinical stage (OR=2.02, 95% CI: 1.17-3.47). Conclusions: The ratio of fibrinogen and albumin could act as a promising prognostic marker in human malignant tumors. It might assist physicians to select optimal treatments by identifying the current status of the patient. Future multicenter clinical trials are needed to validate its applications.

10.
Cancer Manag Res ; 11: 4185-4200, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190988

RESUMO

Background: Numerous studies have reported that systemic immune-inflammation index (SII) and C-reactive protein-to-albumin ratio (CAR) correlate with tumor progression and prognosis in various types of human cancer. The aim of this study is to systematically investigate the clinical significance of SII and CAR in esophageal cancer (EC). Methods: We searched a number of databases for articles reporting the effect of pretreatment SII and CAR on the survival of EC patients. Review Manager 5.3 and STATA/SE 14.1 were applied in this meta-analysis. The multivariable-adjusted hazard ratio (HR) was used for calculating the relationship between SII and CAR and overall survival (OS), and the odds ratio (OR) was applied for the clinical pathology. Results: Five original studies for SII and seven original datasets for CAR were included for analysis. Increased SII showed a significant association with shorter OS in EC patients after surgery (HR: 1.34, 95% CI: 1.15-1.53, P<0.001) and high CAR indicated worse long-term OS in EC (HR: 1.60, 95% CI: 1.29-1.90, P<0.001). Different subgroup analyses were also confirmed the prognostic roles in EC patients. Furthermore, the adverse impacts of elevated SII and CAR on tumor progression were revealed in the infiltration depth, lymph node metastasis, and clinical stage. Conclusions: Both pretreatment SII and CAR might be promising predictors of cancer survival and tumor progression in EC. Further studies are warranted to verify the clinical usefulness in patients with EC.

12.
Environ Sci Pollut Res Int ; 26(22): 23119-23128, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31183760

RESUMO

With the widespread use of metal oxide nanoparticles (MNPs), agricultural soil is gradually becoming a primary sink for MNPs. The effect of these nanoparticles on the fate and the toxicity of co-existing heavy metals is largely unknown. In this paper, pot experiments were conducted to evaluate the impact of ZnO nanoparticles (ZnO-NPs) on Cd toxicity and bioaccumulation in a soil-rice system. Different amounts of ZnO-NPs were added to three different levels of Cd-contaminated paddy soil (L-Cd, 1.0 mg kg-1; M-Cd, 2.5 mg kg-1; H-Cd, 5.0 mg kg-1). The results showed that the addition of ZnO-NPs significantly increased the soil pH value, and the soil pH value increased with the increase in ZnO-NP concentration. Reductions in plant height and biomass under Cd stress were recovered and increased after the addition of ZnO-NPs; the addition of ZnO-NP promoted rice biomass increased by 13~22% and 25~43% in the M-Cd and H-Cd groups, respectively, compared with that of the respective control treatment. A high concentration of ZnO-NPs could increase the concentration of bioavailable Cd in rhizosphere soil. In the L-Cd group, the Cd concentration of the rice in the L-Z500 treatment increased to 0.51 mg kg-1, exceeding the limit for acceptable Cd concentrations in rice of China (0.2 mg kg-1). This work revealed that ZnO-NPs could improve plant growth, especially in the early-growth stage, and alleviate the toxic effects of Cd. However, the addition of high-concentration (500 mg kg-1) ZnO-NPs in the lower Cd pollution soil could significantly facilitate the accumulation of Cd by Oryza sativa L.


Assuntos
Cádmio/análise , Nanopartículas Metálicas/análise , Metais Pesados/análise , Oryza/crescimento & desenvolvimento , Poluentes do Solo/análise , Agricultura , Biomassa , China , Nanopartículas Metálicas/química , Metais Pesados/química , Óxido de Zinco/química
13.
Medicine (Baltimore) ; 98(24): e15982, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31192939

RESUMO

BACKGROUND: FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1), as a novel lncRNA, was reported to be up-regulated in various cancers and involved in tumor progression. This study systematically assessed the prognostic value of FEZF1-AS1 in solid tumors. METHODS: Web of Science, PubMed, EMBASE, Chinese National Knowledge Infrastructure, and Wanfang databases were searched for eligible studies that evaluated the prognostic role of FEZF1-AS1 expression in cancer patients. Pooled hazard ratios (HRs) and combined odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated. The meta-analysis was conducted using Stata/SE 14.1. RESULTS: Fifteen original studies involving 1378 patients were enrolled. Pooled results showed that increased expression of FEZF1-AS1 significantly correlated with shorter overall survival (OS) in cancer patients (HR 2.04, 95% CI 1.60-2.47), and also shorter disease-free survival (DFS) (HR 2.08, 95% CI 1.27-2.89). Additionally, the combined ORs indicated that increased FEZF1-AS1 expression was significantly associated with lymph node metastasis (OR 3.35, 95% CI 1.98-5.67), distant metastasis (OR 3.10, 95% CI 1.86-5.15), poor tumor differentiation (OR 2.90, 95% CI 1.45-5.80), high depth of tumor invasion (OR 2.72, 95% CI 1.36-5.43), and advanced clinical stage (OR 2.76, 95% CI 1.75-4.35). Expression analysis using the Gene Expression Profiling Interactive Analysis database indicated that the expression of FEZF1-AS1 was higher in tumor tissues than that in the corresponding normal tissues. The results of survival analysis revealed that increased FEZF1-AS1 expression was correlated with poor OS and DFS in cancer patients. CONCLUSIONS: LncRNA FEZF1-AS1 may serve as a valuable prognostic biomarker for clinical outcomes in various solid tumors.


Assuntos
Neoplasias/genética , RNA Antissenso/genética , RNA Longo não Codificante/genética , Fatores de Transcrição/genética , Biomarcadores Tumorais/biossíntese , Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Metástase Linfática , Neoplasias/metabolismo , Razão de Chances , Prognóstico , RNA Antissenso/biossíntese , Proteínas Repressoras , Análise de Sobrevida , Regulação para Cima
14.
Parasitol Int ; 67(6): 751-758, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30055333

RESUMO

Intestinal schistosomiasis caused by S. japonicum has long been a threat to the health of residents within endemic areas, especially along the mid-tier of the Yangtze River basin as well as the Dongting and Poyang lakes. Therefore, we collected monitoring data from 2005 to 2014 in Lushan City, Jiujiang City, Jiangxi Province, which is located downstream of Poyang Lake. We conducted a logistic regression analysis in 2005 and in 2008 and then conducted a time series analysis from 2005 to 2014 in Lushan city. The results of the logistic regression analysis showed that after integrated measures were implemented in Lushan city in 2004, the infection rate of intestinal schistosomiasis decreased sharply in different populations, but fishermen had a greater risk of contracting intestinal schistosomiasis in both 2005 and 2008. From the time series analysis, we found that the infection rate decreased sharply from 2005 to 2009 and then increased slowly from 2009 to 2011 before finally becoming relatively stable and the predicated infection rates in HES, SM2, and SM3 are -1.14%, 0.35%, 0.29%, respectively, compared with 0.41% of schistosomiasis infection in 2014, showing a downward trend. Our study indicated that the integrated measures initiated in 2004 in Lushan city had a positive effect on controlling intestinal schistosomiasis, but we should still emphasize special treatment of particular populations, such as fishermen, and should consider environmental changes, such as changes in the water level of Poyang Lake, in the future.


Assuntos
Enteropatias Parasitárias/epidemiologia , Schistosoma japonicum/fisiologia , Esquistossomose Japônica/epidemiologia , Animais , China/epidemiologia , Cidades/epidemiologia , Humanos , Enteropatias Parasitárias/parasitologia , Modelos Logísticos , Fatores de Risco , Esquistossomose Japônica/parasitologia
16.
J Phys Chem B ; 110(27): 13445-52, 2006 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-16821869

RESUMO

Nearly monodisperse flowerlike CeO2 microspheres were synthesized via a simultaneous polymerization-precipitate reaction, metamorphic reconstruction, and mineralization under hydrothermal condition as well as subsequent calcination. The obtained CeO2 microsphere consists of 20-30 nm thick nanosheets as petals. It has an open three-dimensional (3D) porous and hollow structure and possesses high surface area, large pore volume, and marked hydrothermal stability. It can be doped easily after synthesis, and the initial 3D texture is maintained. The controlling factors and a possible formation mechanism are discussed in detail. This novel material can be used as a support for catalysts with various purposes. With CuO loaded on flowerlike CeO2, the catalytic activities and hydrothermal stability of Cu/CeO2 for ethanol stream reforming were examined. At 300 degrees C, the H2 selectivity reached a maximum value of 74.9 mol %, while CO was not detected within the precision of the gas chromatogram. It produced a hydrogen-rich gas mixture in the wide temperature range (300-500 degrees C) and showed excellent hydrothermal stability at high temperature (550 degrees C), which is a good choice for ethanol processors for hydrogen fuel cell applications.

17.
Sci Rep ; 5: 7854, 2015 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-25598010

RESUMO

To explore the importance of soil microbial community composition on explaining the difference in heterotrophic soil respiration (R(h)) across forests, a field investigation was conducted on Rh and soil physiochemical and microbial properties in four subtropical forests in southern China. We observed that Rh differed significantly among forests, being 2.48 ± 0.23, 2.31 ± 0.21, 1.83 ± 0.08 and 1.56 ± 0.15 µmol m(-2) s(-1) in the climax evergreen broadleaf forest (BF), the mixed conifer and broadleaf forest (CF), the conifer plantation (CP), and the native broadleaved species plantation (BP), respectively. Both linear mixed effect model and variance decomposition analysis indicated that soil microbial community composition derived from phospholipid fatty acids (PLFAs) was not the first-order explanatory variable for the R(h) variance across the forests, with the explanatory power being 15.7%. Contrastingly, vegetational attributes such as root biomass (22.6%) and soil substrate availability (18.6%) were more important for explaining the observed R(h) variance. Our results therefore suggest that vegetation attributes and soil carbon pool size, rather than soil microbial community composition, should be preferentially considered to understand the spatial R(h) variance across the subtropical forests in southern China.


Assuntos
Ecossistema , Raízes de Plantas/fisiologia , Microbiologia do Solo , China , Florestas , Processos Heterotróficos , Raízes de Plantas/microbiologia , Clima Tropical
18.
Sci Rep ; 5: 18370, 2015 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-26670822

RESUMO

Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of Rh while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations.


Assuntos
Biomassa , Carbono/metabolismo , Florestas , Solo , Clima Tropical
19.
ACS Appl Mater Interfaces ; 6(22): 19990-6, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25333295

RESUMO

Donor-doped perovskite-type SrTiO3 experiences stoichiometric changes at high temperatures in different Po2 involving the formation of Sr or Ti-rich impurities. NiO is incorporated into the stoichiometric strontium titanate, SrTi0.8Nb0.2O3-δ (STN), to form an A-site deficient perovskite material, (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 (Ni-STN), for balancing the phase transition. Metallic Ni nanoparticles can be released upon reduction instead of forming undesired secondary phases. This material design introduces a simple catalytic modification method with good compositional control of the ceramic backbones, by which transport property and durability of solid oxide fuel cell anodes are largely determined. Using Ni-STN as anodes for solid oxide fuel cells, enhanced catalytic activity and remarkable stability in redox cycling have been achieved. Electrolyte-supported cells with the cell configuration of Ni-STN-SDC anode, La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode produce peak power densities of 612, 794, and 922 mW cm(-2) at 800, 850, and 900 °C, respectively, using H2 as the fuel and air as the oxidant. Minor degradation in fuel cell performance resulted from redox cycling can be recovered upon operating the fuel cells in H2. Such property makes Ni-STN a promising regenerative anode candidate for solid oxide fuel cells.

20.
Adv Mater ; 24(11): 1439-43, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22318883

RESUMO

A novel composite anode material consisting of K(2) NiF(4) -type structured Pr(0.8) Sr(1.2) (Co,Fe)(0.8) Nb(0.2) O(4+δ) (K-PSCFN) matrix with homogenously dispersed nano-sized Co-Fe alloy (CFA) has been obtained by annealing perovskite Pr(0.4) Sr(0.6) Co(0.2) Fe(0.7) Nb(0.1) O(3-δ) (P-PSCFN) in H(2) at 900 °C. The K-PSCFN-CFA composite anode is redox-reversible and has demonstrated similar catalytic activity to Ni-based cermet anode, excellent sulfur tolerance, remarkable coking resistance and robust redox cyclability.


Assuntos
Fontes de Energia Elétrica , Hidrocarbonetos/química , Óxidos/química , Enxofre/química , Eletrodos , Teste de Materiais , Oxirredução
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA