Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.400
Filtrar
1.
J Nanosci Nanotechnol ; 20(5): 3287-3294, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31635677

RESUMO

As the characterizations of electrode are meaningful for electric catalytic efficiency and mechanism, the improvement of electrode have raised considerable public concern in recent decades. However, the metal electrode have the drawbacks of high price and easy for toxicity, nano electrode restricted by difficulties for electrode coating, possibility of agglomeration, and abscission during reactions. Focus on those defects, the proposed study is going to establish a useful technique for polymer combined nano-electrode preparation. The morphology, functional groups, and other characterization of the Pt/TiO2/graphene particles and organic composite nano Pt/TiO2/graphene sheets were analyzed by transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), electrochemical impedance spectroscopy (EIS). To identify the stability of self-prepared electrodes, parameters such as catalysts dosage, current density and pH will be analyzed by using RBK5 as target pollutions. The results shows that after treatment for 50 min under optimized conditions (20 mA, 1 g/L NaCl), the degradation rate of acetaminophen almost reached 100%. After five times recycle, the self-prepared electrode could still maintained a high removal rate of 90%.

2.
Aging (Albany NY) ; 112019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31682592

RESUMO

Dexmedetomidine is known to alleviate cerebral ischemia-reperfusion injury (CIRI). We established a rat model of CIRI, which exhibited higher neurological deficit scores and a greater number of apoptotic cells in the cerebral ischemic penumbra than controls. Dexmedetomidine reversed the neuronal apoptosis and improved neurological function in this model. We then examined Sigma-1 receptor (Sig-1R) expression on the endoplasmic reticulum (ER) in brain tissues at different reperfusion time points. Sig-1R expression increased with CIRI and decreased with increasing reperfusion times. After 24 hours of reperfusion, dexmedetomidine upregulated Sig-1R expression, and ER stress proteins (GRP78, CHOP, JNK and Caspase-3) were detected in brain tissues with Western blotting. Moreover, GRP78 expression followed a pattern similar to Sig-1R. Dexmedetomidine induced GRP78 expression but inhibited CHOP, Caspase-3 and phosphorylated-JNK expression in brain tissues. A Sig-1R-specific inhibitor reduced GRP78 expression and partially inhibited the upregulation of GRP78 by dexmedetomidine. The inhibitor also increased CHOP and Caspase-3 expression and partially reversed the inhibitory effects of dexmedetomidine on these pro-apoptotic ER stress proteins. These results suggest that dexmedetomidine at least partially inhibits ER stress-induced apoptosis by activating Sig-1R, thereby attenuating brain damage after 24 hours of ischemia-reperfusion.

3.
Bioengineered ; 10(1): 635-645, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31680623

RESUMO

Melanoma is a potentially fatal form of skin cancer with great metastatic potential. THOC2 plays a vital role in human biological progression, however, the roles of THOC2 in melanoma tumorigenesis are still unknown. In the present study, our data demonstrated that THOC2 expression was significantly increased in melanoma tissues, and high THOC2 expression was associated with poor overall survival of melanoma patients. THOC2 reduction repressed melanoma cell proliferation and invasion, and induced cell apoptosis in vitro. Microarray data revealed that the cAMP signaling pathway was significantly downregulated in A375 cells transfected with si-THOC2, which was further confirmed by RT-qPCR and bioinformatics analysis. In conclusion, our data indicated that THOC2 might act as an oncogene in melanoma progression through cAMP signaling pathway regulation, which may offer a therapeutic target for melanoma treatment.

4.
Inorg Chem ; 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31689092

RESUMO

A series of lanthanide-titanium oxo clusters (LnTOCs), Ln2Ti8-Ac, Ln2Ti8-p-Toluic, and Ln2Ti8-Anthra (Ln = Eu and Tb), were prepared based on acetic acid (HAc), p-toluic acid (Hp-Toluic), and anthracene-9-carboxylic acid (HAnthra). Crystal structural analysis showed that these clusters possess the same metal topology framework, in which eight Ti4+ ions form a cube and two Ln3+ ions are located on the opposite faces of the cube. The luminescence investigation discovered that the Eu2Ti8-Ac displays the highest quantum yields with 15.6%, and the conjugation effect of ligand substituents can lower the triplet state energy of ligands, thus regulating the luminescence quantum yield of the Ln2Ti8 clusters. These results suggest that the triplet excited-state energy of the ligands should match well with the energy levels of Ln3+ to enhance the luminescence.

5.
IEEE Trans Pattern Anal Mach Intell ; 41(12): 2791-2806, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31689178

RESUMO

This paper studies active relocalization of 6D camera pose from a single reference image, a new and challenging problem in computer vision and robotics. Straightforward active camera relocalization (ACR) is a tricky and expensive task that requires elaborate hand-eye calibration on precision robotic platforms. In this paper, we show that high-quality camera relocalization can be achieved in an active and much easier way. We propose a hand-eye calibration free approach to actively relocating the camera to the same 6D pose that produces the input reference image. We theoretically prove that, given bounded unknown hand-eye pose displacement, this approach is able to rapidly reduce both 3D relative rotational and translational pose between current camera and the reference one to an identical matrix and a zero vector, respectively. Based on these findings, we develop an effective ACR algorithm with fast convergence rate, reliable accuracy and robustness. Extensive experiments validate the effectiveness and feasibility of our approach on both laboratory tests and challenging real-world applications in fine-grained change monitoring of cultural heritages.

6.
J Ethnopharmacol ; : 112372, 2019 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-31683036

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Recipes (Qingre Jiedu (QJ), Wenyang Yiqi (WYYQ) and Huo Xue (HX)) in Qishen granules (QSG) are believed to synergistically exert cardio-protective effects. However, the underlying pattern of each decomposed recipe in QSG and their synergistic effects in the treatment of heart failure (HF) are not clear. OBJECTIVE: The purpose of this study is to explore the biological contributions of decomposed recipes to therapeutic effects of QSG and reveal the pharmacological mechanism of QSG in treating HF. MATERIALS AND METHODS: The therapeutic effects of QSG or its recipes on heart failure were examined in wet-lab at both transcription and phenotypic level using HF Sprague-Dawley rats. Sequencing and transcriptome analyses were performed using in silico approaches including identification of differentially expressed genes, pathway enrichment and protein-protein interaction network studies. Specially, an optimized in silico quantitative pathway analysis that maximally extracted gene expression information was developed to reveal differentially expressed pathways (DEPs) among various groups, and is publicly available as R package QPA on GitHub (https://github.com/github-gs/QPA). Finally, the HF-related genes predicted using DEP approach were validated by quantitative real-time polymerase chain reaction and western blot. RESULTS: Multiple key genes and the associated signaling pathways were shown to be highly relevant for the therapeutic effect of QSG. Decreased expression of Spp1 gene required for inflammatory signaling and profibrotic signaling were observed in failing hearts treated with QJ, WYYQ and HX. Decreased expression of Cx3cr1 gene required for inflammatory signaling was observed in failing hearts treated with WYYQ and HX. Decreased expression of Myc gene required for oxidative stress and Fgfr2 gene required for profibrotic signaling were observed in failing hearts treated with HX and WYYQ, respectively. Increased expression of Adcy1 gene required for cAMP-PKA signaling cascade was observed in failing hearts treated with WYYQ and HX. CONCLUSIONS: Our study suggests that QJ, WYYQ and HX recipes in QSG achieve synergistic and complementary therapeutic effects through alleviating inflammatory responses, attenuating ventricular remodeling and enhancing myocardial energy supply.

7.
Plant Physiol Biochem ; 145: 174-183, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31704591

RESUMO

Drought significantly affects plant growth and has devastating effects on crop production, NAC transcription factors respond to abiotic stresses by activating gene expression. In this study, a maize NAC transcription factor, ZmNAC33, was cloned and characterized its function in Arabidopsis. Transient transformation in Arabidopsis leaves mesophyll protoplasts and trans-activation assays in yeast showed that ZmNAC33 was localized in the nucleus and had transactivation activity. qRT-PCR analysis showed that ZmNAC33 in maize was induced by drought, high salinity and abscisic acid (ABA) stress. Promoter analysis identified multiple stress-related cis-acting elements in the promoter region of ZmNAC33. In ZmNAC33 transgenic Arabidopsis, germination rates were higher than in wild type plants under ABA and osmotic stress at the germination stage, and overexpression lines exhibited higher survival rates and higher antioxidant enzyme activities compared with wild type under drought stress. These results indicate that ZmNAC33 actes as a positive regulator in drought tolerance in plants.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31676129

RESUMO

Developing highly active and durable catalyst is of pivotal importance in fuel cells, owing to excessive consumption of fossil fuels. Herein, porous dendritic PtRuPd nanospheres (PtRuPd NSs) were synthesized by a facile hexadecylpyridinium chloride (HDPC)-mediated one-pot aqueous method with ascorbic acid (AA) as the reducing agent. The as-obtained PtRuPd NSs displayed high-efficient catalytic activity and durability for ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR). It exhibited enlarged mass activity (MA, 1.368 A mg-1) compared to commercial Pt/C (1.100 A mg-1) for EGOR. Besides, the onset potential (Eonset, 0.930 V) and half-wave potential (E1/2, 0.852 V) of PtRuPd NSs were more positive relative to homemade PtPd NSs (0.905 and 0.840 V), PdRu NSs (0.895 and 0.839 V), and commercial Pt/C (0.910 and 0.822 V) toward ORR. This work provides some valuable guidelines for producing novel trimetallic nanocatalysts in fuel cells.

9.
Oncogene ; 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31676872

RESUMO

Colorectal cancer (CRC) is a common cancer type and a threat to human health. Tumor budding (TB) is the presence of a single cancer cell or clusters of up to five cancer cells prior to the invasive front of an aggressive carcinoma and is an independent prognosis factor for CRC. The molecular mechanism of TB is still unclear, and drugs that inhibit this process are still in the blank stage. This study found that TBs exhibit characteristics of partial EMT with a decreased expression of E-cadherin and no substantial differences in the expression of N-cadherin and vimentin. We also observed the interaction of integrin with extracellular matrix components, laminin-5γ2 (LN-5γ2), play essential roles in the TB of CRC. We then verified that the interaction between LN-5γ2 and integrin ß1 promotes the TB of CRC via the activation of FAK and Yes-associated proteins (YAP). A natural drug monomer, cucurbitacin B, was screened using virtual screening methods for the interaction interface of proteins. We found that this monomer could block the interaction interface between LN-5γ2 and integrin ß1 and substantially inhibit the TB of CRC cells via inactivation of YAP. This study provides new insights into the mechanism of TB mechanism and the development of drugs targeting the TB of CRC.

10.
J Periodontal Res ; 2019 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-31677272

RESUMO

BACKGROUND AND OBJECTIVES: Peri-implantitis remains a challenge for dental implant therapy, and the prognosis of non-surgical therapy for peri-implantitis is unsatisfactory. In order to reveal the impact of non-surgical mechanical debridement therapy on microbial communities, we investigated the subgingival microbial communities of healthy implants and implants with peri-implantitis, both before and after the therapy. MATERIAL AND METHODS: Subgingival plaques were collected from patients with healthy dental implants (HC; n = 10) and from patients with peri-implantitis (n = 13) before and after non-surgical mechanical debridement therapy. The treatment was conducted using curettes for submucosal debridement followed by irrigation with 0.2% (w/v) chlorhexidine, with re-examination 1 month later. 16S rRNA pyrosequencing was used to analyze the subgingival microbiome, and co-occurrence networks were adopted to explore the interactions between pathogens in the microbial communities. RESULTS: A total of 506 955 high-quality reads were generated, and 2222 operational taxonomic units were finally detected using a 97% similarity cutoff, with a mean of 249 ± 69 per sample. The peri-implantitis sites harbored similar microbial communities before and after the treatment, as demonstrated by the microbial diversity, relative abundance, and prevalence of bacteria. Most importantly, the microbial community structures were stable before and after non-surgical therapy based on the microbial diversity and bacterial composition, as well as the interactions between key pathogens, including Enterobacteriaceae, Selenomonas sputigena, Parvimonas, Eubacterium infirmum, Campylobacter gracilis, Tannerella forsythia, and Fusobacterium, which were measured using a co-occurrence network analysis. Periodontal pathogens were also detected in subgingival plaque after the treatment. Distinct microbial communities were found between the healthy and peri-implantitis sites. CONCLUSION: Our results demonstrate that non-surgical mechanical debridement therapy did not significantly affect the subgingival microbial communities in peri-implantitis, and the stable microbial networks created via interactions among pathogens may be responsible for the poor prognosis of peri-implantitis treatment.

11.
Biosens Bioelectron ; 148: 111823, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31671357

RESUMO

Nonmetallic plasmonic MoS2 nanosheets were synthesized by hydrothermal top-down method. MoS2 nanosheets had shown strong surface plasmon coupling (SPC) light absorption in the visible and near-infrared region. Herein, the nonmetallic plasmonic MoS2 nanosheets were employed to enhance the electrochemiluminescence (ECL) signal of sulfur doped boron nitrogen QDs (S-BN QDs) in this work. It is important to regulate the distance between ECL luminophore and plasmonic nanoparticles. On one hand, too closed distance can cause energy or electron transfer, which could quench the ECL intensity of nano-luminophore. On the other hand, plasmonic nanostructure cannot significantly affect the luminescence in the far distance. Therefore, we discussed the distance-dependent plasmon-enhanced ECL in detail with different length DNA chains. Furthermore, we constructed a hybridization chain reaction (HCR) amplification ECL sensing mode with the SPC-ECL strategy. The proposed DNA sensor can quantify hepatitis C virus (HCV) gene from 0.5 pmoL/L to 1 nmoL/L with a limit of detection (LOD) of 0.17 pmoL/L.

12.
Environ Int ; 133(Pt B): 105252, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31678907

RESUMO

Solid (biomass and coal) fuels burned for residential heating are major sources of atmospheric volatile organic compounds (VOCs). In this study, VOC samples were collected in-situ from chimneys in 10 typical heating scenarios in rural areas of the Guanzhong Plain. A modified SUMA canister approach was then employed, followed by gas chromatography/mass spectrometry analysis. Emission factors (EFs) (as received basis) of targeted non-methane VOCs (NMVOCs) varied from 90.3 ±â€¯29.3 to 12300 ±â€¯1510 mg kg-1 in descending order of fuel wood > maize straw > bitumite ≫ anthracite (p < 0.05). Both clean stove and coal briquetting technologies effectively reduced VOC EFs compared with traditional heating methods. The EFs of methane (CH4) had similar characteristics to those of NMVOCs. However, they yielded different correlations with CO because of their differing mechanisms of formation. Coefficient of divergence (CD) values showed that a semi-gasifier has a limited effect on changing VOC profiles compared with a traditional stove using the same fuels. However, different types of fuel produce CD values over 0.50, which should therefore be classified as different sub-categories in source apportionment models. Correlation analysis showed that volatile matter content (V%) and modified combustion efficiency (MCE) were the two primary factors influencing NMVOC and CH4 emissions. A stepwise linear regression analysis showed that V%, MCE, and element nitrogen content (N%) can be used to predict total VOC (TVOCs, including CH4 and NMVOCs) emissions with regression coefficients of 0.23, -72.8 and -6.53, respectively (R2 = 0.92, p < 0.001). Ozone formation potential (OFP) EFs from burning solid fuel ranged from 72 to 18680 mg kg-1, with an approximate 50% contribution from alkenes. VOCs from burning solid fuel were equivalent to 62 to 22200 mg kg-1 secondary organic aerosol formation potential (SOAP), most of which (>95%) were contributed by aromatics. A semi-gasifier and coal briquettes were effective in reducing TVOC emissions, even when used in conjunction with a traditional stove and fuels. It is estimated that over 15,000 ton year-1 emissions can be reduced in Guanzhong Plain by adopting a semi-gasifier and coal briquettes, resulting in a 57,000 and 65,000 ton year-1 reduction of OFP and SOAP emissions, respectively. These results demonstrate that the use of clean heating technologies in Guanzhong Plain has considerable potential in relation to emissions reduction and thus provides a feasible solution to mitigate VOCs and related secondary pollutants emitted by residential solid fuel burning.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31681624

RESUMO

Background and Aims: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. However, the underlying mechanism of IBS is not fully understood. The aim of this study was to investigate potential mechanism and novel biomarkers of IBS through evaluation of the metabolomic and microbiologic profile. Methods: Fecal samples were collected from 15 irritable bowel syndrome patients and 15 healthy controls. By using gas chromatography coupled to time-of-flight mass spectrometry (GC-TOFMS) and 16S rDNA amplicon sequencing, fecal metabolites and microbiota of healthy controls and the IBS patients were measured. Results: IBS patients had a significantly differential metabolite profile as compared to healthy controls, and 4 clusters with 31 metabolites, including a group of amino acids and fatty acids, were significantly up-regulated as compared to the healthy controls. In addition, 19 microbes were significantly up-regulated, and 12 microbes were down-regulated in the IBS group, when compared with the healthy controls. Some clusters of fecal metabolites or microorganisms were significantly correlated with the severity of IBS symptoms, such as the frequency of abdominal pain/discomfort and the number of bowel movements. Correlation of the metabolite levels with abundances of microbial genera showed some statistically significant metabolite-microbe associations. Four differentially abundant amino acids clustered together were positively correlated with some microbes, including Lachnospira, Clostridium, and so on. Conclusion: The finding of this study puts a global perspective on metabolomics and microbiota profiling in IBS patients and provides a theoretical basis for future research on pathophysiology of IBS.

14.
Int J Clin Oncol ; 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701291

RESUMO

BACKGROUND: Pancreatic cancer (PC) is a seriously malignant tumor with a low 5-year survival rate. The relationship between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and PC has been reported by several studies. However, the results were controversial. Thus, we conducted a meta-analysis to summarize available data on MTHFR gene and PC. METHODS: We searched PubMed, Embase, Web of Science, Wanfang, CNKI databases prior to July 2019. Data were analyzed by RevMan 5.3 and STATA 12.0 software. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the strength of the association. Subgroup analysis, sensitivity analysis and assessment of publication bias were performed in this study. RESULTS: Ten articles with 17 reports (10 for C677T, 7 for A1298C) were eligible for inclusion in the meta-analysis (1864 cases and 3165 controls for C677T, and 1488 cases and 1946 controls for A1298C). Our meta-analysis detected that C677T was associated with PC for three genetic models (allele model: OR = 1.24, 95% CI: 1.00-1.53, P = 0.047; recessive model: OR = 1.39, 95% CI: 1.04-1.86, P = 0.027; homozygous model: OR = 1.60, 95% CI: 1.04-2.45, P = 0.034). In the stratified analyses according to ethnicity, source of controls and genotyping method, significant association was observed in genotyping method subgroup. For the A1298C polymorphism, no significant association was observed either in overall analysis or in subgroup analysis under all genetic models. CONCLUSIONS: MTHFR gene C677T rather than A1298C polymorphism may be associated with PC. Larger sample size studies should be performed to find the association between MTHFR gene and PC.

15.
Zhongguo Ying Yong Sheng Li Xue Za Zhi ; 35(4): 381-384, 2019 Jul 28.
Artigo em Chinês | MEDLINE | ID: mdl-31701728

RESUMO

OBJECTIVE: To investigate the expression of 2-type small conductance-Ca2+-activating-K+ (SK2) channel protein in hypertensive rat myocardial cells. METHODS: Twelve healthy adult male SD rats were randomly divided into control group (n=5) and experimental group (n=7). The rats of experimental group were injected intraperitoneally with N'-nitro-L-arginine (L-NNA 15 mg/(kg·d))while the rats of control group were injected intraperitoneally with isometrical normal saline(15 ml/(kg·d )). The body weight, blood pressure and electrocardiogram of the rats were measured every week. After 4 weeks, the rats were sacrificed to obtain hearts, and the expression of SK2 channel protein in myocardium was detected by Western blot. RESULTS: After 4 weeks of administration, compared with the control group, the blood pressure in the experimental group was significantly elevated (P<0.05), QRS duration and R-R interval were prolonged, and the expressions of SK2 channel in the atrial and ventricular tissue of the experimental group were significantly higher than those in the control group (1.12±0.18,1.64±0.26, P < 0.05). CONCLUSION: The expressions of atrial and ventricular SK2 pathway are increased in hypertensive model rats. It may be one of the mechanism leading to arrhythmias in hypertensive model rats and can provide new ideas and strategies for the treatment and prognosis of hypertensive diseases.

16.
Artigo em Inglês | MEDLINE | ID: mdl-31701994

RESUMO

Summer and winter fine particulate matter (PM2.5) samples were collected to provide insight into the seasonal variations of the optical properties and source profiles of PM2.5 black carbon (BC) and brown carbon (BrC) in Xi'an, China. The average PM2.5 mass concentration during the winter haze (WH) period was 292.5 µg m-3, which was 2.6, 5.0 and 9.2 times higher than that during winter non-haze (WNH), summer haze (SH), and summer non-haze (SNH) periods, respectively. Regarding optical properties, the PM2.5 chemical-derived light extinction coefficient was the highest during the WH period (1019.2 Mm-1) and decreased by approximately one-fourth in the SH period (237.6 Mm-1). During the WH period, the light absorption coefficient of BC (babs-BC) was considerably higher than that during the SH period; this is attributable to the thick coatings of inorganic ions on BC and intensive fossil fuel and biomass burning emissions in winter. Source apportionment also proved that fossil fuels were the major emission source of BC in SH and WH periods with high light absorption coefficient babs_FF (fossil fuel) fractions (>70%). Biomass burning contributed to 25.8% of BC in the winter haze period, but to only 5.4% of BC in the summer haze period. The mass absorption coefficient of BC (MAC-BC) was higher in summer, as it was considerably influenced by vehicle emissions, whereas it was lower in winter due to the strong influences of biomass burning. Moreover, the high light absorption coefficient of BrC (babs-BrC) in both WH and WNH indicated substantial light absorption during winter; however, this coefficient was considerably lower in summer. A remarkable difference in the diurnal pattern of haze between babs-BrC and babs-BC indicated that BC leads to a severe visibility reduction during traffic rush hours. In addition, the BrC abundance observed in Xi'an revealed different diurnal patterns in WH and SH periods, which can be attributed to different secondary formation processes. SH BrC was generally contributed by photochemical-derived secondary organic carbon (SOC) whereas the abundant WH BrC was mainly transformed from aqueous-SOC.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31671860

RESUMO

In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.

18.
Carbohydr Polym ; 226: 115304, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582069

RESUMO

Medicinal herb Bletilla striata as a traditional Chinese herb has been used to treat alimentary canal mucosal damage, ulcers, bruises, and burns for thousands of years. Despite numerous efforts directed at the development of Bletilla striata products, the challenge of preparing Bletilla striata hemostasis dressings while simultaneously maintaining portability and high hemostasis performance has not yet been addressed. Herein, we describe a Bletilla striata polysaccharide (BSP) sponge with hierarchical aligned porous channels formed via directional freeze technology. The microstructure and mechanical property of the BSP sponges could be controlled by modifying the BSP concentration. Notably, in vivo animal studies indicated that BSP sponges show high biocompatibility and degradation and possess excellent hemostasis capability. In addition, BSP sponges showed accelerated wound healing in comparison to commercial dressings. Thus, our study indicates that the constructed BSP sponges could find potential application in dressings for efficient wound healing.

19.
Nat Mater ; 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591530

RESUMO

Alternative technologies are required in order to meet a worldwide demand for clean non-polluting energy sources. Thermoelectric generators, which generate electricity from heat in a compact and reliable manner, are potential devices for waste heat recovery. However, thermoelectric performance, as encapsulated by the figure of merit ZT, has remained at around 1.0 at room temperature, which has limited practical applications. Here, we study the effects of pressure on ZT in Cr-doped PbSe, which has a maximum ZT of less than 1.0 at a temperature of about 700 K. By applying external pressure using a diamond anvil cell, we obtained a room-temperature ZT value of about 1.7. From thermoelectric, magnetoresistance and Raman measurements, as well as density functional theory calculations, a pressure-driven topological phase transition is found to enable this enhancement. Experiments also support the appearance of a topological crystalline insulator after the transition. These findings point to the possibility of using compression to increase not just ZT in existing thermoelectric materials, but also the possibility of realizing topological crystalline insulators.

20.
J Periodontal Res ; 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31593304

RESUMO

BACKGROUND AND OBJECTIVE: Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Wnt5a is the activating ligand of the non-canonical Wnt signaling pathways and plays important roles in leukocyte infiltration and cytokine/ chemokine production in inflammatory disorders. Previous studies showed that Wnt5a was significantly up-regulated in gingival tissues of chronic and aggressive periodontitis. However, the roles and the regulatory mechanisms of Wnt5a in peri-implantitis are not well known. METHODS: The expression of Wnt5a in gingival tissues collected from 8 healthy implant patients and 8 peri-implantitis patients was analyzed by Western blotting and immunofluorescence. Porphyromonas gingivalis infected macrophages isolated from the peripheral blood of healthy volunteers were used as an in vitro cellular model of peri-implantitis. Using neutralizing antibodies, inhibitors and siRNA, the production and roles of Wnt5a in peri-implantitis were assessed by immunofluorescence, quantitative polymerase chain reaction (RT-PCR) and Western blotting. Unpaired two-tailed Student's t test was used to compare qRT-PCR and Western blotting results. P ≤ .05 was considered statistically significant. RESULTS: Wnt5a was highly expressed in the gingival tissues of peri-implantitis patients. Compared to controls, Wnt5a increased in P gingivalis infected macrophages. Wnt5a production in response to P gingivalis infection was dependent on LOX-1 and TLR4. Compared to controls, Wnt5a knockdown impaired IL-1ß, MCP-1, and MMP2 production induced by P gingivalis infection. CONCLUSION: Our results indicate that Wnt5a is involved in LOX-1 and TLR4 induced inflammatory signature via inflammatory cytokines production in response to P gingivalis infection. These findings demonstrate that Wnt5a maybe an important component of the host immune response in peri-implantitis.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA