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1.
Oncol Lett ; 19(4): 2765-2772, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32218829

RESUMO

MYB protooncogene-like 2 (MYBL2) is a transcription factor that is upregulated and significantly associated with various human cancer types. However, the potential role of MYBL2 in clear cell renal cell carcinoma (ccRCC) is yet to be elucidated. Therefore, the expression and biological functions of MYBL2 in ccRCC were assessed in the current study using The Cancer Genome Atlas (TCGA). A Wilcoxon signed-rank test was performed to compare MYBL2 expression between ccRCC and normal tissues. Moreover, the association between MYBL2 expression and various clinicopathological factors was estimated using both the Wilcoxon signed-rank test and logistic regression. The differences in prognosis between patients with high- and low-MYBL2 expression were analyzed via the Kaplan-Meier method and Cox regression analysis. Finally, gene set enrichment analysis (GSEA) was performed to investigate the biofunctions of MYBL2 in ccRCC. It was revealed that MYBL2 was upregulated in ccRCC, and that the MYBL2 high-expression phenotype was significantly associated with sex, a high histological grade, an advanced clinical stage, tumor stage, lymph node metastasis, distant metastasis and poor overall survival (OS). It was also revealed, via the Cox regression analysis, that the upregulation of MYBL2 expression was able to independently predict a poor prognosis in patients with ccRCC. GSEA indicated that the intestinal immune network for IgA production, primary immunodeficiency, the janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway, the cytosolic DNA-sensing pathway, the p53 signaling pathway and the chemokine signaling pathway were all enriched in the high-MYBL2 expression datasets. In conclusion, the present findings indicate that MYBL2 may be used as an independent prognostic factor in patients with ccRCC.

2.
Environ Pollut ; 261: 114225, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32220754

RESUMO

The presence of Eschericia coli O157:H7 in the natural environment is a serious threat to human health. The native microbial community in soil plays an important role in resisting E. coli O157:H7 invasion. This study examined the responses of soil microbial community to E. coli O157:H7 invasion during a 32-day incubation. The E. coli O157:H7 persisted longer in γ-irradiated soil than non-irradiated soil while glucose addition decreased its persistence in the irradiated soil which was associated with an increasing recovery of the native community. The invasion of E. coli O157:H7 increased soil organic carbon mineralization, an indicator of microbial activity, in both non-irradiated and irradiated soils, while glucose addition significantly promoted the carbon mineralization process. The 16S rRNA sequencing data showed the gradual recovery of the native bacterial population including specific taxa such as proteobacteria and actinobacteria following irradiation. It is concluded that soil microbial function and structure can affect persistence of E. coli O157:H7 and that lower biodiversity of the native community favors its persistence.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32030884

RESUMO

HOX transcript antisense intergenic RNA (HOTAIR) is considered a diagnostic biomarker for cancer; however, results of previous studies on HOTAIR are inconsistent. In this meta-analysis, we aimed to investigate the role of HOTAIR in cancer diagnosis. Medline, PubMed, Embase, Ovid, Web of Science and Cochrane databases were searched for relevant literature up to May 2019. Over all, we included 20 studies from 17 articles on the role of HOTAIR in cancer diagnosis (individual diagnosis) and 7 studies from 6 articles on the role of HOTAIR along with other biomarkers in cancer diagnosis (combinative diagnosis). The sensitivity and specificity of HOTAIR-mediated individual diagnosis of cancers were 0.80 (95% confidence interval [CI], 0.74-0.85) and 0.74 (95% CI, 0.66-0.81), respectively. The sensitivity and specificity of HOTAIR-mediated combinative diagnosis of cancer were 0.82 (95% CI, 0.77-0.87) and 0.86 (95% CI, 0.80-0.91), respectively. The areas under the receiver operating characteristic curve for individual and combinative diagnoses was 0.84 (95% CI, 0.81-0.87) and 0.91 (95% CI, 0.88-0.93), respectively, indicating that a combinative diagnosis has a relatively better diagnostic accuracy (z = -2.22, P = 0.01) than individual diagnosis. In conclusion, HOTAIR levels might be a promising biomarker in cancer diagnosis. In addition, using HOTAIR in combination with other biomarkers showed a relatively better diagnostic accuracy than HOTAIR alone.

4.
Chem Commun (Camb) ; 56(22): 3325-3328, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32083264

RESUMO

The first coordination disk-type nano-Saturn complexes, [Cu10(Mim)10]⊃C60 and [Cu10(Mim)10]⊃C70 (Mim = 2-methylimidazolate), were assembled under one-pot solvothermal conditions. The highest number of 30 C-Hπ interactions between the [Cu10(Mim)10] disk and the C60/C70 surfaces drives the formation of the nano-Saturns. The calculated interaction energy is much larger than that of most of the reported disk-type nano-Saturns. Different photoinduced charge/energy transfer mechanisms are present for both nano-Saturn systems to quench the intrinsic luminescence of the [Cu10(Mim)10] disk.

5.
Sci Total Environ ; 716: 137054, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32036140

RESUMO

Tidal flow constructed wetlands (TF CWs) have been considered an effective approach to treat contaminated river water, as well as a significant role in global matter cycles, especially for carbon and nitrogen. Notably, it has been thought that methane oxidation was completely catalyzed by the aerobic process, ignoring the anaerobic methane oxidation, such as the nitrite-dependent anaerobic methane oxidation (n-damo) process. In our current work, therefore, we used molecular and stable isotopes to investigate the biodiversity, quantity and potential rate of n-damo bacteria in the TF CWs located in the Xisha Wetland Park in the Yangtze River estuary, China. The results revealed that n-damo process was active in the collected soil cores, with a decreasing trend along water depths and rates ranging from 8.48 to 23.45 nmol CO2 g-1 dry soil d-1. The n-damo bacterial contributions to CH4 oxidation and N2 production in TF CWs reached 9.49-26.26% and 20.73-47.11%, respectively, suggesting that n-damo bacteria was an important nitrogen and methane sink in the TF CWs, but had been previously overlooked. The copy numbers of total bacterial 16S rRNA and pmoA genes were 1.84-11.21 × 109 and 0.59-2.72 × 106 copies g-1 ds, respectively, as the higher abundance was found in the soil at lower water levels during tidal submergence. Diverse n-damo bacterial 16S rRNA gene sequences belonged to group B, C and D were measured, and it was found that group B and C were the most frequently measured n-damo clusters in the TF CWs. In addition, nitrite was the key factor regulating the n-damo bacterial distribution in the TF CWs. This study would broaden our horizons and help us better understand the nitrogen and methane cycles in tidal ecosystems.

6.
J Chromatogr A ; : 460962, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32067760

RESUMO

Human papillomavirus (HPV) vaccination is the most effective mean to prevent HPV infection and cervical carcinoma. Licensed HPV prophylactic vaccines are formulated to contain a defined amount of different major capsid protein (L1), the critical antigen to elicit protection. No method is currently available to simultaneously quantify individual L1s in multivalent vaccines, presenting a daunting challenge for the quality control of HPV vaccines. Here, HPV16 and HPV18 L1 can be analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using tryptic digestion without pre-digestion reduction and alkylation in multiple reaction monitoring (MRM) mode. Two signature peptides were selected to be the markers of the two L1s and can be well separated within 5.1 min. Their linear calibration curves were both obtained in the range of 20-500 nmol/L (R2 > 0.990). To HPV16 L1, intra/inter assay precisions and accuracies of the assay were below 11% and between 83.96-113.57%. While for HPV18 L1, they were below 12% and between 81.40-103.49%. In addition, the limits of quantitation (LOQ) were as low as 2.8 nmol/L for HPV16 L1 and 1.7 nmol/L for HPV18 L1, respectively, representing about 68 and 112 times more sensitive than those obtained with Smith Bicinchoninic Acid (BCA) assay. This LC-MS/MS method can be applied to the quantification of both bulk products and the final multivalent vaccines. This method is superior to the current assays in terms of sensitivity, specificity, precision, accuracy and throughput; it could become the method of choice for absolute quantification of proteins in multivalent vaccines.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31989771

RESUMO

Materials exhibiting excitation wavelength-dependent photoluminescence (Ex-De PL) in the visible region have potential applications in bioimaging, optoelectronics and anti-counterfeiting. Two multifunctional, chiral [Au(NHC)2 ][Au(CN)2 ] (NHC=(4R,5R)/(4S,5S)-1,3-dimethyl-4,5-diphenyl-4,5-dihydro-imidazolin-2-ylidene) complex double salts display Ex-De circularly polarized luminescence (CPL) in doped polymer films and in ground powder. Emission maxima can be dynamically tuned from 440 to 530 nm by changing the excitation wavelength. The continuously tunable photoluminescence is proposed to originate from multiple emissive excited states as a result of the existence of varied AuI ⋅⋅⋅AuI distances in ground state. The steric properties of the NHC ligand are crucial to the tuning of AuI ⋅⋅⋅AuI distances. An anti-counterfeiting application using these two salts is demonstrated.

8.
Biotechnol Lett ; 42(4): 537-549, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31974647

RESUMO

OBJECTIVES: 2,3-Butanediol (2,3-BD) is widely used in several chemical syntheses as well as the manufacture of plastics, solvents, and antifreeze formulations, and can be manufactured by microbial glucose fermentation. Conventional (2,3-BD) fermentation typically has low productivity, yield, and purity, and is expensive for commercial applications. We aimed to delete the lactate dehydrogenase and acetate kinase (ldhA and ack) genes in Klebsiella pneumoniae HD79 by using λRed homologous recombination technology, to eliminate by-products and thereby improve (2,3-BD) production. We also analyzed the resulting gene changes by using transcriptomics. RESULTS: The yield of (2,3-BD) from the mutant Klebsiella strain was 46.21 g/L, the conversion rate was 0.47 g/g, and the productivity was 0.64 g/L·h, which represented increases of 54.9%, 20.5%, and 106.5% respectively, compared to (WT) strains. Lactate and acetate decreased by 48.2% and 62.8%, respectively. Transcriptomics analysis showed that 4628 genes were differentially expressed (404 significantly up-regulated and 162 significantly down-regulated). Moreover, the (2,3-BD) operon genes were differentially expressed. CONCLUSION: Our data showed that the biosynthesis of (2,3-BD) was regulated by inducers (lactate and acetate), a regulator (BudR), and carbon flux. Elimination of acidic by-products by ldhA and ack knockdown significantly improved (2,3-BD) production. Our results provide a deeper understanding of the mechanisms underlying (2,3-BD) production, and form a molecular basis for the improvement this process by genetic modification in the future.

9.
Ann Bot ; 125(4): 677-690, 2020 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-31922527

RESUMO

BACKGROUND AND AIMS: Hosting several global biodiversity hotspots, the region of the Qinghai-Tibetan Plateau (QTP) is exceptionally species-rich and harbours a remarkable level of endemism. Yet, despite a growing number of studies, factors fostering divergence, speciation and ultimately diversity remain poorly understood for QTP alpine plants. This is particularly the case for the role of hybridization. Here, we explored the evolutionary history of three closely related Gentiana endemic species, and tested whether our results supported the mountain geo-biodiversity hypothesis (MGH). METHODS: We genotyped 69 populations across the QTP with one chloroplast marker and 12 nuclear microsatellite loci. We performed phylogeographical analysis, Bayesian clustering, approximate Bayesian computation and principal components analysis to explore their genetic relationship and evolutionary history. In addition, we modelled their distribution under different climates. KEY RESULTS: Each species was composed of two geographically distinct clades, corresponding to the south-eastern and north-western parts of their distribution. Thus Gentiana veitchiorum and G. lawrencei var. farreri, which diverged recently, appear to have shared at least refugia in the past, from which their range expanded later on. Indeed, climatic niche modelling showed that both species went through continuous expansion from the Last Interglacial Maximum to the present day. Moreover, we have evidence of hybridization in the northwest clade of G. lawrencei var. farreri, which probably occurred in the refugium located on the plateau platform. Furthermore, phylogenetic and population genetic analyses suggested that G. dolichocalyx should be a geographically limited distinct species with low genetic differentiation from G. lawrencei var. farreri. CONCLUSIONS: Climatic fluctuations in the region of the QTP have played an important role in shaping the current genetic structure of G. lawrencei var. farreri and G. veitchiorum. We argue that a species pump effect did occur prior to the Last Interglacial Maximum, thus lending support to the MGH. However, our results do depart from expectations as suggested in the MGH for more recent distribution range and hybridization dynamics.

10.
J Hazard Mater ; 390: 122160, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31999958

RESUMO

An oxygen-constrained system of crude oil reservoir environment was constructed to stimulate the growth of indigenous microbes, such as petroleum hydrocarbon-degrading bacteria. Addition of nitrogen and phosphorus sources was investigated for the growth of petroleum hydrocarbon-degrading bacteria. The results show that nitrates and phosphates stimulated the growth of the bacteria and promoted the biodegradation of crude oil as the sole carbon source in this process. The minimum surface tension was 29.63 mN/m when the amounts of the nitrogen (NaNO3: [Formula: see text]  = 2:1) and phosphorus (KH2PO4: NaH2PO4 = 5:2) sources added were 0.8 wt% and 1.4 wt%, respectively. Furthermore, the dominant petroleum hydrocarbon-degrading bacteria were shifted from Arcobacter in production water to Pseudomonas after the first subculture and then to Bacillus after the sixth subculture. The heteroatom groups in the crude oil were biodegraded simultaneously with normal alkanes and alkyl cyclohexanes. Addition of the nutrients resulted in microbial growth, microbial community shift, and enhanced microbial degradation.

11.
Environ Sci Pollut Res Int ; 27(1): 636-646, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808093

RESUMO

Biofiltration is one kind of common technology used for treating micro-polluted brackish aquaculture wastewater. Based on the characteristics of actual water quality, a novel two-stage biofiltration system was set up to reduce potential nutrient pollution brought by the frequent exchange of water in brackish pond aquaculture. Zeolite was selected as filtration media for the first stage and pyrite mixed with a small amount of sulfur for the second stage. Apart from the adsorption of nutrients exerted by these natural minerals, biofilm played a leading role in nutrient removal. The surface and internal pore of zeolite-sheltered nitrifiers and sulfur-containing compounds enhanced autotrophic denitrification. It was found that ammonia adsorption capacity of zeolite was reduced by nearly 58% when salinity was increased to 1.5%, while phosphate adsorption capacity of pyrite was hardly influenced and systematic hydraulic retention time (HRT) of 24 h was proven appropriate, 9.6 h and 14.4 h for the two stages, respectively. Meanwhile, removal efficiency of 96.5% for NH4+-N and 92.1% for total inorganic nitrogen (TIN) was achieved under this condition. The analysis of microbial community of biofilm indicated that dominant genera responsible for nitritation and nitration on the surface of zeolite were Nitrosomonas and Nitrospira, respectively. Dominant genera responsible for autotrophic denitrification on the surface of pyrite and sulfur were both Thiobacillus. In addition, Ferritrophicum, related to the iron-oxidizing bacterium, also coexisted due to biological oxidation of pyrite. Long-term operation verified applicability and stability of this two-stage biofiltration system for brackish aquaculture wastewater purification.

12.
J Hazard Mater ; 387: 121684, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31784128

RESUMO

Microbial degradation is considered to be the most acceptable method for degradation of chlorimuron-ethyl, a typical long-term residual sulfonylurea herbicide, but the underlying mechanism at the genetic and biochemical levels is unclear. In this work, the genome sequence of the chlorimuron-ethyl-degrading bacterium Rhodococcus erythropolis D310-1 was completed, and the gene clusters responsible for the degradation of chlorimuron-ethyl in D310-1 were predicted. A carboxylesterase gene, carE, suggested to be responsible for carboxylesterase de-esterification, was cloned from D310-1. CarE was expressed in Escherichia coli BL21 and purified to homogeneity. The active site of the chlorimuron-ethyl-degrading enzyme CarE and the biochemical activities of CarE were elucidated. The results demonstrated that CarE is involved in catalyzing the de-esterification of chlorimuron-ethyl. A carE deletion mutant strain, D310-1ΔcarE, was constructed, and the chlorimuron-ethyl degradation rate in the presence of 100 mg L-1 chlorimuron-ethyl within 120 h decreased from 86.5 % (wild-type strain D310-1) to 58.2 % (mutant strain D310-1ΔcarE). Introduction of the plasmid pNit-carE restored the ability of the mutant strain to utilize chlorimuron-ethyl. This study is the first to demonstrate that carboxylesterase can catalyze the de-esterification reaction of chlorimuron-ethyl and provides new insights into the mechanism underlying the degradation of sulfonylurea herbicides and a theoretical basis for the utilization of enzyme resources.

13.
Sci Total Environ ; 704: 135331, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31831232

RESUMO

Rhodococcus sp. WB9, a strain isolated from polycyclic aromatic hydrocarbons contaminated soil, degraded phenanthrene (PHE, 100 mg L-1) completely within 4 days. 18 metabolites were identified during PHE degradation, including 5 different hydroxyphenanthrene compounds resulted from multiple routes of initial monooxygenase attack. Initial dioxygenation dominantly occurred on 3,4-C positions, followed by meta-cleavage to form 1-hydroxy-2-naphthoic acid (1H2N). More than 95.2% of 1H2N was transported to and kept in extracellular solution without further degradation. However, intracellular 1H2N was converted to 1,2-naphthalenediol that was branched to produce salicylate and phthalate. Furthermore, 131 genes in strain WB9 genome were related to aromatic hydrocarbons catabolism, including the gene coding for salicylate 1-monooxygenase that catalyzed the oxidation of 1H2N to 1,2-naphthalenediol, and complete gene sets for the transformation of salicylate and phthalate toward tricarboxylic acid (TCA) cycle. Metabolic and genomic analyses reveal that strain WB9 has the ability to metabolize intracellular 1H2N to TCA cycle intermediates, but the extracellular 1H2N can't enter the cells, restricting 1H2N bioavailability and PHE mineralization.


Assuntos
Biodegradação Ambiental , Naftóis/metabolismo , Fenantrenos/metabolismo , Rhodococcus/metabolismo
14.
J Phys Chem Lett ; 11(1): 199-205, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31841006

RESUMO

In this work, a new two-dimensional Cd-based (F2CHCH2NH3)2CdBr4 perovskite (Cd-P) with indirect bandgap and a direct Pb-based (F2CHCH2NH3)2PbBr4 (Pb-P) are successfully synthesized with isostructural features. Compared to the blueish white light emission of Pb-P, almost no white light can be observed for Cd-P due to the forbidden transition of self-trapped exciton (STE) emission. Interestingly, the white light emission of CdxPb1-x-P (x represents the feed ratio of Cd) is significantly improved with the photoluminescence (PL) quantum yield (QY) raising from <1% to 32.5% by alloying these two isostructural perovskites, which is attributed to the breaking of selection rules for forbidden transitions of STEs with Jahn-Teller like octahedral distortion, as suggested by the results from density functional theory (DFT) calculations and time-resolved spectroscopies. This study demonstrates the intriguing effect of alloying on activating STE emission as an effective approach to control and enhance the optical properties of metal halide perovskites.

15.
Bioresour Technol ; 300: 122651, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31887578

RESUMO

Three ecological floating beds (EFBs) with different additional electron donors including sodium thiosulfate, mixed electron donors of sodium thiosulfate and sodium acetate and without additional electron donors were established to compare the differences of nitrogen removal efficiency, nitrous oxide emission, microbial community and functional gene between autotrophic and mixotrophic denitrification. Results showed denitrification efficiency was nearly 100% in both autotrophic and mixotrophic process when electron donors were sufficient while that ranged from 4 to 43% without additional electron donors. Sodium acetate addition could effectively decrease sulfate concentration in effluent and nitrogen oxide flux. In addition, high-throughput sequencing analysis revealed autotrophic denitrifying bacteria were dominant in autotrophic denitrification while autotrophic, facultative and heterotrophic denitrifying bacteria coexisted in mixotrophic denitrification, and there was no dominant genus. For EFB with mixed external autotrophic and heterotrophic electron donors, it can not only achieve better denitrification efficiency, but also reduce the emission of nitrous oxide.


Assuntos
Desnitrificação , Óxido Nitroso , Processos Autotróficos , Reatores Biológicos , Nitratos , Sulfatos , Tiossulfatos
16.
PeerJ ; 7: e8025, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31799070

RESUMO

Chloroplasts are typically inherited from the female parent and are haploid in most angiosperms, but rare intra-individual heteroplasmy in plastid genomes has been reported in plants. Here, we report an example of plastome heteroplasmy and its characteristics in Gentiana tongolensis (Gentianaceae). The plastid genome of G. tongolensis is 145,757 bp in size and is missing parts of petD gene when compared with other Gentiana species. A total of 112 single nucleotide polymorphisms (SNPs) and 31 indels with frequencies of more than 2% were detected in the plastid genome, and most were located in protein coding regions. Most sites with SNP frequencies of more than 10% were located in six genes in the LSC region. After verification via cloning and Sanger sequencing at three loci, heteroplasmy was identified in different individuals. The cause of heteroplasmy at the nucleotide level in plastome of G. tongolensis is unclear from the present data, although biparental plastid inheritance and transfer of plastid DNA seem to be most likely. This study implies that botanists should reconsider the heredity and evolution of chloroplasts and be cautious with using chloroplasts as genetic markers, especially in Gentiana.

17.
Technol Cancer Res Treat ; 18: 1533033819892256, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31829105

RESUMO

PURPOSE: This study aimed to investigate the effects of microRNA-222-3p on activated B cell-like-type diffuse large B-cell lymphoma cells and the regulatory relationship between microRNA-222-3p and phosphatase 2 regulatory subunit B alpha. METHOD: The expression of microRNA-222-3p was detected in activated B cell-like-type diffuse large B-cell lymphoma tissues and cells by quantitative reverse transcription polymerase chain reaction. The regulatory effects of microRNA-222-3p on the proliferation, invasion, and apoptosis of activated B cell-like-type diffuse large B-cell lymphoma cells were analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation, flow cytometry, and Transwell assay. The regulatory relationship between microRNA-222-3p and phosphatase 2 regulatory subunit B alpha was determined by luciferase reporter gene and RNA pull-down assay. In addition, the effects of microRNA-222-3p on tumor growth were further analyzed in mice. RESULTS: MicroRNA-222-3p and phosphatase 2 regulatory subunit B alpha were significantly up- and downregulated in activated B cell-like-type diffuse large B-cell lymphoma tissues and cells, respectively. Phosphatase 2 regulatory subunit B alpha was a target of microRNA-222-3p. MicroRNA-222-3p promoted the proliferation and invasion and inhibited the apoptosis of activated B cell-like-type diffuse large B-cell lymphoma cells. Phosphatase 2 regulatory subunit B alpha reversed the tumor-promoting effects of microRNA-222-3p on activated B cell-like-type diffuse large B-cell lymphoma cells. In addition, microRNA-222-3p promoted the tumor growth in mice and downregulated phosphatase 2 regulatory subunit B alpha in tumor tissues. CONCLUSION: MicroRNA-222-3p promoted the proliferation and invasion and inhibited the apoptosis of activated B cell-like-type diffuse large B-cell lymphoma cells through suppressing phosphatase 2 regulatory subunit B alpha expression.

18.
Chem Commun (Camb) ; 55(96): 14490-14493, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31729522

RESUMO

A biomimetic CoPe@CdS/rGO hybrid that self-assembles via the integration of a molecular cobalt catalyst and CdS nano-semiconductor on reduced graphene oxide was constructed for boosting photocatalytic H2 production. Photoinduced electron transfer from CdS/rGO to the molecular catalyst occurs and a long-lived charge-separation state forms for high H2 production.

19.
Sci Rep ; 9(1): 15772, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673044

RESUMO

Low permeability oil reservoirs are a widespread petroleum reservoir type all over the world. Therefore, methods to recover these reservoirs efficiently are of importance to guarantee energy supply. Here we report our novel stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery. We aimed to investigate the characteristics of indigenous bacterial communities with changes in water cut in reservoirs by high-throughput sequencing technology, and reveal the mechanism and characteristics of the crude oil biotreatment under different crude oil-water ratio conditions and the optimum activation time of indigenous functional microbial groups in reservoirs. The indigenous microbial metabolism products were characterized by gas chromatography mass spectrometry. Results showed that Acinetobacter (47.1%) and Pseudomones (19.8%) were the main functional genus of crude oil degradation at the optimal activation time, and can reduce the viscosity of crude oil from 8.33 to 5.75 mPa·s. The dominant bacteria genus for oil recovery after activation of the production fluids was similar to those in the reservoirs with water cut of 60-80%. Furthermore seven mechanism pathways of enhancing oil recovery by the synergistic of functional microbial groups and their metabolites under different water cut conditions in low permeability reservoirs have been established.

20.
J Phys Chem Lett ; 10(21): 6499-6503, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31589456

RESUMO

Two widely used ultraviolet filters, oxybenzone and dioxybenzone, are applied in a variety of areas, particularly in sunscreen cosmetics. Ultrafast femtosecond transient absorption is utilized to trace the excited states and transient states of the nanocrystalline suspension and solution phase of these two molecules. The analysis reveals the intriguing discovery that the transient species of the oxybenzone nanocrystalline suspension have shorter lifetimes than that in solution. The energy dissipation mechanism of these molecules is simulated by density functional theory calculations, and the potential energy surface calculations and the single-crystal structure can well explain the fast decay dynamics of the nanocrystalline transient states of these two molecules.

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