Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Total Environ ; 710: 135258, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-31866106

RESUMO

In order to reduce the loss of anaerobic ammonia oxidation (anammox) sludge and stabilize the reaction microenvironment, polyvinyl alcohol - polypropylene (PVA-PP) was used to encapsulate anammox bacteria on a filler. The influence of different inoculation amounts (2, 4, 6 and 8%) on the overall nitrogen removal process was first compared and then the anammox characteristics of the immobilized filler under the influence of different environmental factors were evaluated through batch experiments. The results show that the biomass only affected the growth rate of the activity during the logarithmic phase, while the total nitrogen removal rate (NRR) tended to be similar after 99 d of culture. The NRR reached 1.83 kg·(m3·d)-1 on day 140, which was 9.4 times that of suspended sludge before encapsulation, and the structure of embedding filler was complete without shedding. Scanning electron microscopy (SEM) showed that the internal porous network structure formed channels and a large number of anammox bacteria were observed around. Microbial community analysis of the 16S rDNA gene showed that the diversity was maintained in the entrapped carrier. Furthermore, the effective enrichment of the anammox functional bacteria Candidatus Kuenenia (AF375995.1) increarsed from 11.06% to 32.55%. The PVA-PP immobilized filler fit well with the biological nitrogen removal kinetic model and could also achieve coupling of anammox and denitrification. The inhibition effect of the organic carbon source interference and starvation on anammox bacteria was significantly weakened.


Assuntos
Biomassa , Anaerobiose , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução , Esgotos
2.
Ecol Evol ; 9(15): 8714-8723, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31410274

RESUMO

Examining the coordination of leaf and fine root traits not only aids a better understanding of plant ecological strategies from a whole-plant perspective, but also helps improve the prediction of belowground properties from aboveground traits. The relationships between leaf and fine root traits have been extensively explored at global and regional scales, but remain unclear at local scales. Here, we measured six pairs of analogous leaf and fine root traits related to resource economy and organ size for coexisting dominant and subordinate vascular plants at three successional stages of temperate forest swamps in Lingfeng National Nature Reserve in the Greater Hinggan Mountains, NE China. Leaf and fine root traits related to resource acquisition (e.g., specific leaf area [SLA], leaf N, leaf P, root water content, and root P) decreased with succession. Overall, we found strong linear relationships between leaf dry matter content (LDMC) and root water content, and between leaf and root C, N, and P concentrations, but only weak correlations were observed between leaf area and root diameter, and between SLA and specific root length (SRL). The strong relationships between LDMC and root water content and between leaf and root C, N, and P held at the early and late stages, but disappeared at the middle stage. Besides, C and P of leaves were significantly correlated with those of roots for woody plants, while strong linkages existed between LDMC and root water content and between leaf N and root N for herbaceous species. These results provided evidence for the existence of strong coordination between leaf and root traits at the local scale. Meanwhile, the leaf-root trait relationships could be modulated by successional stage and growth form, indicating the complexity of coordination of aboveground and belowground traits at the local scale.

3.
J Environ Sci (China) ; 83: 8-20, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221390

RESUMO

With rapid economic growth and urbanization, the Yangtze River Delta (YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014-2016. In recent years, the concentrations of all air pollutants, except O3, decreased. Spatially, the PM2.5, PM10, SO2, and CO concentrations were higher in the northern YRD region, and NO2 and O3 were higher in the central YRD region. Based on the number of non-attainment days (i.e., days with air quality index greater than 100), PM2.5 was the largest contributor to air pollution in the YRD region, followed by O3, PM10, and NO2. However, particulate matter pollution has declined gradually, while O3 pollution worsened. Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM2.5 concentration was inversely related to wind speed, while O3 concentration was positively correlated with temperature and negatively correlated with relative humidity. The air quality improvement in recent years was mainly attributed to emission reductions. During 2014-2016, PM2.5, PM10, SO2, NOx, CO, NH3, and volatile organic compound (VOC) emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and 0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Conceitos Meteorológicos , China , Meteorologia , Ozônio , Material Particulado/análise , Rios , Estações do Ano , Temperatura , Urbanização
4.
Sci Total Environ ; 653: 1364-1376, 2019 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-30759576

RESUMO

A novel back-trajectory approach was adopted to determine the origins of black carbon (BC) and carbon monoxide (CO) transported to Beijing, Tianjin and Hebei. Results showed that the transport efficiency was controlled mainly by mid-latitude westerlies in winter, the South Asian monsoon in summer and prevailing westerly and northwesterly winds in spring and autumn. Hebei was identified as the most important source region of both BC (respectively accounting for 55% and 49%) and CO (39% and 38%) transported to Beijing and Tianjin. Inner Mongolia contributed more to the effective emission intensity (EEI) in winter than in summer for both BC and CO transported to Beijing and Tianjin. Shandong was responsible for higher EEI in summer than in winter. The six provinces making the greatest contributions to BC transported to Hebei were Shandong (19%), Shanxi (19%), Inner Mongolia (17%), Beijing (11%), Henan (11%), and Tianjin (10%), whereas those making the greatest contributions to CO transported to Hebei were Shandong (20%), Inner Mongolia (10%), Tianjin (9%), Henan (9%), Shanxi (9%), and Beijing (8%). In summary, Hebei, Inner Mongolia, Shandong, Tianjin and Shanxi were determined as the dominant source regions of not only BC but also CO transported to Beijing. Hebei, Shandong, Beijing, Inner Mongolia, Henan, Liaoning and Shanxi were relatively important source regions for Tianjin. Shandong, Shanxi, Inner Mongolia, Beijing, Henan, Tianjin, Liaoning, Jiangsu and Anhui were the main source regions for Hebei. Residential and industrial sectors were the dominant sectors for BC and CO transported to the receptors, respectively. These results are consistent with the results of previous studies. Finally, comparing the observed ΔBC/ΔCO ratio with the enhancement ratio of the EEI of BC with that of CO (ΔEEIBC/ΔEEICO) at Miyun site, we further confirmed that the EEI can be used to represent the amounts of BC and CO reaching receptors.

5.
Cancer Chemother Pharmacol ; 83(3): 443-449, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30511217

RESUMO

PURPOSE: The standard treatment for peripheral T-cell lymphomas (PTCLs) is undetermined. We designed a CHOPE/G regimen (cyclophosphamide, pirarubicin, vincristine, prednisolone, and etoposide alternating with a gemcitabine-based regimen) as the first-line treatment of PTCLs and compared with CHOP (cyclophosphamide, pirarubicin, vincristine, and prednisolone) and CHOPE (CHOP plus etoposide) regimen to evaluate the optimal chemotherapy regimen. METHODS: 116 previously untreated PTCL patients received CHOP (N = 46), CHOPE (N = 46), or CHOPE/G (N = 24) regimen at Peking University Cancer Hospital from 2009 to 2017 and were retrospectively analyzed. RESULTS: The overall response rates (ORRs) of the CHOP, CHOPE, and CHOPE/G groups were 82.6%, 76.1%, and 75.0% (p = 0.673), with complete response (CR) rates of 32.6%, 56.5%, and 45.7% (p = 0.063), respectively. Within a median follow-up time of 35.5 months, the 3-year overall survival (OS) rates of the CHOP, CHOPE, and CHOPE/G groups were 37.0%, 47.0%, and 56.3% (p = 0.107), and the 3-year progression-free survival (PFS) rates were 19.9%, 29.9%, and 5.3% (p = 0.093), respectively. Compared with the CHOP regimen alone, CHOPE had a significantly higher CR rate (p = 0.021) with more favorable OS (p = 0.046). The CHOPE/G regimen did not improve the ORR, CR rate, or OS compared with either the CHOP or CHOPE, with a significantly poorer PFS compared with the CHOPE regimen (p = 0.029). Anemia and thrombocytopenia occurred most frequently in the CHOPE/G group (anemia 83.3%, p = 0.035; thrombocytopenia 50%, p = 0.015). CONCLUSIONS: Compared with CHOP alone, CHOPE regimen improved the efficacy and survival; while the addition of gemcitabine in the front-line therapy resulted in more adverse events without benefit of survival.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Desoxicitidina/análogos & derivados , Etoposídeo/administração & dosagem , Linfoma de Células T Periférico/tratamento farmacológico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia/induzido quimicamente , Anemia/epidemiologia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Etoposídeo/efeitos adversos , Feminino , Seguimentos , Humanos , Linfoma de Células T Periférico/mortalidade , Masculino , Pessoa de Meia-Idade , Prednisolona/administração & dosagem , Prednisolona/efeitos adversos , Intervalo Livre de Progressão , Estudos Retrospectivos , Trombocitopenia/induzido quimicamente , Trombocitopenia/epidemiologia , Vincristina/administração & dosagem , Vincristina/efeitos adversos , Adulto Jovem
6.
R Soc Open Sci ; 5(6): 172370, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30110426

RESUMO

Lithium-ion batteries are widely used in various industries, such as portable electronic devices, mobile phones, new energy car batteries, etc., and show great potential for more demanding applications like electric vehicles. Among advanced anode materials applied to lithium-ion batteries, silicon-carbon anodes have been explored extensively due to their high capacity, good operation potential, environmental friendliness and high abundance. Silicon-carbon anodes have demonstrated great potential as an anode material for lithium-ion batteries because they have perfectly improved the problems that existed in silicon anodes, such as the particle pulverization, shedding and failures of electrochemical performance during lithiation and delithiation. However, there are still some problems, such as low first discharge efficiency, poor conductivity and poor cycling performance, which need to be improved. This paper mainly presents some methods for solving the existing problems of silicon-carbon anode materials through different perspectives.

7.
Environ Pollut ; 242(Pt B): 1308-1318, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30121485

RESUMO

Analysis of observed PM2.5 in Beijing since 2009 reveals that winter haze over North China Plain (NCP) peaked in 2012 and 2013 and there was an improvement in air quality until 2016. The variation of wintertime PM2.5 from 2009 to 2016 is influenced by both emission changes and meteorology conditions, and we quantified the relative contributions from these two aspects. Sensitivity simulation by GEOS-Chem suggested that emission reductions over NCP in 2013-2017 caused 10% decrease of regional mean PM2.5 concentration in 2016 winter compared to 2012 winter level. We removed emission influence on PM2.5 to get PM2.5 that influenced by meteorology (met-influenced PM2.5). For met-influenced PM2.5, compared to original-observed PM2.5(the US Embassy data), percentage of clean days (daily PM2.5 ≤ 75 µg m-3) decreases while that of polluted (75 µg m-3 < daily PM2.5 ≤150 µg m-3) and heavily polluted (150 µg m-3 < daily PM2.5 ≤ 250 µg m-3) days increases. However, proportion of extremely polluted (daily PM2.5 > 250 µg m-3) days stays unchanged, even if emission reduction is doubled, indicating that the extremely polluted situation over NCP is dominated by meteorological conditions, and emission control from 2013 to 2017 has little effects on the extremely polluted days. We developed an effective haze day index (HDI) to represent the weather conditions conducive to haze days. HDI is constructed based on the normalized near surface meridional wind (V850), temperature difference (δT) between near surface (850 hPa) and upper atmosphere (250 hPa), and the relative humidity at 1000 hPa (RH1000). HDI is skillful to detect 72% of the severe haze days (daily PM2.5 > 150 µg m-3). On average, the anomalously high V850 is the main cause of severe haze, while in 2012 winter, RH1000 favorable for secondary aerosols' formation is the largest contributor to haze.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Material Particulado/análise , Smog/análise , Atmosfera/análise , Pequim , China , Monitoramento Ambiental , Estações do Ano , Tempo (Meteorologia) , Vento
8.
Huan Jing Ke Xue ; 39(7): 3042-3050, 2018 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-29962124

RESUMO

PM2.5 samples were collected at a background site of the Yangtze River Delta in China, during summertime, of which the carbonaceous components, i.e., OC and EC, and water-soluble inorganic ions, including sulfate, nitrate, and ammonium, were quantified. The average concentrations of OC and EC in PM2.5 during summer at Lin'an were (14.3±3.95) µg·m-3 and (3.33±1.47) µg·m-3, respectively. Compared to an urban site, the correlation between OC and EC during summertime in Lin'an, which was a rural site, was relatively weak (R2=0.31, P<0.01). The concentrations of secondary inorganic aerosols (sulfate as SO42-, nitrate as NO3-, and ammonium as NH4+) were much higher than those of other water-soluble inorganic ions, with average values of (8.70±5.66), (2.04±1.07), and (3.25±2.29) µg·m-3, respectively. Based on long-term intensive observations, combined with the analysis of back trajectory and fire spots observations, it was revealed that regional transport and stable synoptic conditions both play important roles in controlling the variations in aerosol chemical components. During the transition from clean to hazy days, the EC and POC fractions showed no obvious variation; in contrast, the SOC fraction decreased obviously. Unlike for SOAs, relative contributions of sulfate and ammonia to PM2.5 increased during hazy days, suggesting enhanced chemical production via other pathways for these two secondary inorganic ions, probably through heterogeneous reactions.

9.
Chemosphere ; 150: 365-377, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26921589

RESUMO

Saccharides are important constituents of atmospheric particulate matter (PM). In order to better understand the sources and seasonal variations of saccharides in aerosols in Beijing, China, saccharide composition was measured in ambient PM samples collected at an urban site in Beijing. The highest concentrations of total saccharides in Beijing were observed in autumn, while an episode with abnormal high total saccharide levels was observed from 15 to 23 June, 2011, due to extensive agricultural residue burning in northern China during the wheat harvest season. Compared to the other two categories of saccharides, sugars and sugar alcohols, anhydrosugars were the predominant saccharide group, indicating that biomass burning contributions to Beijing urban aerosol were significant. Ambient sugar and sugar alcohol levels in summer and autumn were higher than those in spring and winter, while they were more abundant in PM2.5 during winter time. Levoglucosan was the most abundant saccharide compound in both PM2.5 and PM10, the annual contributions of which to total measured saccharides in PM2.5 and PM10 were 61.5% and 54.1%, respectively. To further investigate the sources of the saccharides in ambient aerosols in Beijing, the PM10 datasets were subjected to positive matrix factorization (PMF) analysis. Based on the objective function to be minimized and the interpretable factors identified by PMF, six factors appeared to be optimal as to the probable origin of saccharides in the atmosphere in Beijing, including biomass burning, soil or dust, isoprene SOA and the direct release of airborne fungal spores and pollen.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Estações do Ano , Aerossóis , Ar/análise , Pequim , Butadienos/análise , Carboidratos/análise , Poeira/análise , Hemiterpenos/análise , Tamanho da Partícula , Pentanos/análise , Solo/química
10.
J Colloid Interface Sci ; 453: 209-215, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25985425

RESUMO

This study first reports the fabrication of a super-amphiphilic surface using PET films with a silica-polyurethane hybrid top-coat layer through a non-thermal, one-atmospheric-pressure plasma treatment. This surface displays contact angle close to zero with both aqueous and oily liquids, which has attracted enormous attention for a wide-range of practical applications. We systematically investigated the influence of the plasma treatment time on the wetting behavior of the silica-polyurethane coated PET surface. The changes in morphology and chemical composition of PET surfaces before and after a plasma treatment were analyzed. In order to gain an insight into the formation of a super-amphiphilic PET surface and optimize the conditions under which super-amphiphilicity can be realized, we used a hemi-wicking action as a theoretical model and experimentally verified it through determining the critical angle. We also proposed a guide for designing a nano-sphere patterned PDMS surface which can generate super-wetting properties after a plasma treatment.

11.
Nanotechnology ; 26(14): 145602, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25786181

RESUMO

The upconversion luminescence (UCL) enhancement based on the surface plasmonic resonance (SPR) of noble metals is a promising way to improve UCL efficiency. However, it is still a challenge to achieve stable and effective UCL enhancement. Here, we present the preparation of the porous Ag/YVO4:Yb(3+), Er(3+) composite film via a simple double annealing method. It is exciting to observe that a maximum 36-fold ((2)H11/2-(4)I15/2) and 30-fold ((4)S3/2-(4)I15/2) UCL enhancement in the porous Ag/YVO4:Yb(3+), Er(3+) composite film, attributed to the effective coupling between SPR and the excitation light by adjusting the SPR peak to the excitation wavelength, controlling the effective coupling distance and improving the scattering-absorption ratio. Furthermore, the enhancement factor strongly depended on the excitation power and the Er(3+) concentration.

12.
PLoS One ; 9(1): e86895, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24489802

RESUMO

The SNAC1 gene belongs to the stress-related NAC superfamily of transcription factors. It was identified from rice and overexpressed in cotton cultivar YZ1 by Agrobacterium tumefaciens-mediated transformation. SNAC1-overexpressing cotton plants showed more vigorous growth, especially in terms of root development, than the wild-type plants in the presence of 250 mM NaCl under hydroponic growth conditions. The content of proline was enhanced but the MDA content was decreased in the transgenic cotton seedlings under drought and salt treatments compared to the wild-type. Furthermore, SNAC1-overexpressing cotton plants also displayed significantly improved tolerance to both drought and salt stresses in the greenhouse. The performances of the SNAC1-overexpressing lines under drought and salt stress were significantly better than those of the wild-type in terms of the boll number. During the drought and salt treatments, the transpiration rate of transgenic plants significantly decreased in comparison to the wild-type, but the photosynthesis rate maintained the same at the flowering stage in the transgenic plants. These results suggested that overexpression of SNAC1 improve more tolerance to drought and salt in cotton through enhanced root development and reduced transpiration rates.


Assuntos
Secas , Gossypium/fisiologia , Oryza/genética , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Transpiração Vegetal/fisiologia , Tolerância ao Sal/genética , Biomassa , Genes de Plantas , Vetores Genéticos , Gossypium/efeitos dos fármacos , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Hidroponia , Oryza/efeitos dos fármacos , Fenótipo , Fotossíntese/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Transpiração Vegetal/efeitos dos fármacos , Plantas Geneticamente Modificadas , Tolerância ao Sal/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/genética , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Transformação Genética/efeitos dos fármacos
13.
Sci Rep ; 3: 3183, 2013 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24292725

RESUMO

This study proposes a method for manufacturing high-performance electrode materials in which controlling the shape of the current collector and electrode material for a Li-ion capacitor (LIC). In particular, the proposed LIC manufacturing method maintains the high voltage of a cell by using a microdome-patterned electrode material, allowing for reversible reactions between the Li-ion and the active material for an extended period of time. As a result, the LICs exhibit initial capacities of approximately 42 F g⁻¹, even at 60 A g⁻¹. The LICs also exhibit good cycle performance up to approximately 15,000 cycles. In addition, these advancements allow for a considerably higher energy density than other existing capacitor systems. The energy density of the proposed LICs is approximately nine, two, and 1.5 times higher than those of the electrochemical double layer capacitor (EDLC), AC/LiMn2O4 hybrid capacitor, and intrinsic Si/AC LIC, respectively.

14.
Appl Opt ; 52(31): 7486-93, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24216647

RESUMO

A multiple-image encryption and authentication approach by space multiplexing has been proposed. The redundant spaces in the previous security systems employing sparse representation strategy are optimized. With the proposal the information of multiple images can be integrated into a synthesized ciphertext that is convenient for storage and transmission. Only when all the keys are correct can the information of the primary images be authenticated. Computer simulation results have demonstrated that the proposed method is feasible and effective. Moreover, the proposal is also proved to be robust against occlusion and noise attacks.

15.
J Nanosci Nanotechnol ; 13(2): 1594-7, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23646688

RESUMO

Si(x)Sb2Te material system is novel for phase-change random access memory applications. Its properties are more outstanding than the widely used material Ge2Sb2Te5. Etching process is one of the critical steps in the device fabrication. The etching characteristics of phase-change material Si(x)Sb2Te were studied with CF4/Ar gas mixture by a reactive ion etching system. The changes of etching rate, etching profile and surface root-mean-square roughness resulted from variation of the gas-mixing ratio were investigated under constant pressure (50 mTorr) and applying power (200 W). Si0.34Sb2Te is with the highest phase-change speed and the lowest power consumption in the PCRAM memory among these compositions, which means it is the most promising candidate for the PCRAM applications. So the most optimized CF4/Ar gas ratio for Si0.34Sb2Te was studied, the value is 25/25. The etching rate is 155 nm/min, and the selectivity of Si0.34Sb2Te to SiO2 is as high as 3.4 times. Furthermore, the smooth surface was achieved with this optimized gas ratio.

16.
Cell Res ; 20(7): 784-93, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20548334

RESUMO

Emerging evidence has shown the association of aberrantly expressed microRNAs (miRNAs) with tumor development and progression. However, little is known about the potential role of miRNAs in gastric carcinogenesis. Here, we performed miRNA microarray to screen miRNAs differentially expressed in the paired gastric cancer and their adjacent nontumor tissues and found that miR-375 was greatly downregulated in gastric cancer tissues. Quantitative real-time PCR analysis verified that miR-375 expression was significantly decreased in more than 90% of primary gastric cancers compared with their nontumor counterparts from patients undergoing gastric resection. Overexpression of miR-375 significantly inhibited gastric cancer cell proliferation in vitro and in vivo. Forced expression of miR-375 in gastric cancer cells significantly reduced the protein level of Janus kinase 2 (JAK2) and repressed the activity of a luciferase reporter carrying the 3'-untranslated region of JAK2, which was abolished by mutation of the predicted miR-375-binding site, indicating that JAK2 may be a miR-375 target gene. Either inhibition of JAK2 activity by AG490 or silencing of JAK2 by RNAi suppressed gastric cancer cell proliferation resembling that of miR-375 overexpression. Moreover, ectopic expression of JAK2 can partially reverse the inhibition of cell proliferation caused by miR-375. Finally, we found a significant inverse correlation between miR-375 expression and JAK2 protein level in gastric cancer. Thus, these data suggest that miR-375 may function as a tumor suppressor to regulate gastric cancer cell proliferation potentially by targeting the JAK2 oncogene, implicating a role of miR-375 in the pathogenesis of gastric cancer.


Assuntos
Janus Quinase 2/antagonistas & inibidores , MicroRNAs/genética , Neoplasias Gástricas/genética , Animais , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo , Feminino , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Camundongos , MicroRNAs/fisiologia , Transplante de Neoplasias , Neoplasias Gástricas/etiologia , Transplante Heterólogo
17.
J Phys Chem B ; 112(47): 14829-35, 2008 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-18975893

RESUMO

A conductive polyaniline/poly(ethylene terephthalate) (PANI/PET) composite film was fabricated via the oxidative graft copolymerization of aniline (ANI) onto the plasma-induced poly(acrylic acid) (PAAc) grafted PET surface. The attenuated total reflectance Fourier transform infrared spectroscopy spectra (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that PANI was successfully grafted onto the surface of the PAAc-g-PET films. The effects of the experimental conditions on the percentage of PANI grafted onto the PAAc-g-PET films were extensively investigated. A very high grafting percentage of ANI can be obtained through the acid-base reaction between the aniline monomer and PAAc on the PAAc-g-PET surface at high temperature. As a result, the grafting percentage of PANI can be increased to as high as 12.18 wt %, which causes the surface resistance of the PANI-g-PAAc-g-PET film to be reduced to about 1000 Omega/sq. We predicted that this is because of the high flexibility of the PAAc molecular chains and high solubility of aniline, both of which facilitate the binding of aniline to PAAc during this high temperature acid-base reaction. It was observed by atomic force microscopy (AFM) that the PANI-modified PET surface exhibits higher size irregularity and surface roughness, which further indicated that a much greater number of aniline molecules can be reactively bonded to and distributed along the grafted AAc chains and that the PANI-g-PAAc-g-PET surface resulting from the sequential oxidative graft copolymerization can possess higher electrical conductivity.


Assuntos
Resinas Acrílicas/química , Compostos de Anilina/química , Polietilenoglicóis/química , Polímeros/química , Microscopia de Força Atômica , Oxirredução , Polietilenotereftalatos , Análise Espectral
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA