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2.
Cells ; 8(11)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703479

RESUMO

It is known that many diseases are caused by mutations or abnormalities in microRNA (miRNA). The usual method to predict miRNA disease relationships is to build a high-quality similarity network of diseases and miRNAs. All unobserved associations are ranked by their similarity scores, such that a higher score indicates a greater probability of a potential connection. However, this approach does not utilize information within the network. Therefore, in this study, we propose a machine learning method, called STIM, which uses network topology information to predict disease-miRNA associations. In contrast to the conventional approach, STIM constructs features according to information on similarity and topology in networks and then uses a machine learning model to predict potential associations. To verify the reliability and accuracy of our method, we compared STIM to other classical algorithms. The results of fivefold cross validation demonstrated that STIM outperforms many existing methods, particularly in terms of the area under the curve. In addition, the top 30 candidate miRNAs recommended by STIM in a case study of lung neoplasm have been confirmed in previous experiments, which proved the validity of the method.

4.
Environ Sci Pollut Res Int ; 26(31): 32574-32588, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31630354

RESUMO

The current studies had already revealed the hydrocarbons could migrate from relatively high hydrocarbon potential stratum to shallow groundwater by corrosion emission and extraction emission in karst area and further impact on human health. Then, the comprehensive experiments were used to understand the mechanism and process of hydrocarbon emission as a continuation of a long-term study on original high hydrocarbon groundwater in shallow Triassic aquifer, taking northwest Guizhou, China, as a reference. The results determined water-rock interaction that lead to the hydrocarbon emission into groundwater with salinity acting as the main driving force. Relatively high salinity promotes the rock corrosion and hydrocarbon emission in the study area. The hydrocarbon emission process varied with different strata, as the results show that the hydrocarbon uniformly distributed in T2g3 than that in T1yn4. Furthermore, the stratum with uniformly distributed hydrocarbon would likely contain high hydrocarbon groundwater, as determined by the process of sedimentation. In addition, "corrosion rate estimation method" and "mineral constituent estimation method" were firstly employed to estimate the hydrocarbon concentration in groundwater to date. Compared with the hydrocarbon concentration of local groundwater samples (0 to 0.14 mg L-1), the result of "mineral constituent estimation method" was analogous to measured value of groundwater samples in the area (0.05 to 0.50 mg L-1), indicating the concentration of hydrocarbon could be estimated by mineral constitutions of groundwater, which was related to the concentration of Ca2+ and Mg2+. Based on the methods and theories in this study, the concentration of original hydrocarbon in shallow groundwater could be estimated and help to understand the mechanism of water-rock interaction in shallow aquifer and original high hydrocarbon groundwater strategic assessment.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31569753

RESUMO

Background: Cadmium (Cd) pollution poses a threat to human health. Examination of the spatial distribution of Cd in soils can be used to assess the risks posed to humans and the environment. Objective: This study determined the enrichment rules and factors influencing Cd pollution in Nansha, and evaluated the pollution characteristics and bioavailability of Cd in quaternary sediments through 7 deep soil profiles (0-200 cm), 4 boreholes, and 348 topsoil (0-20 cm) samples. Methods: The geo-accumulation index (Igeo) and the potential ecological risk index (Er) were used to assess ecological risk, and bioavailability was determined using multivariate, spatial distribution, and correlation matrix analyses. Results: From the Er, 52% of Nansha was classed as being at very high risk of Cd pollution; a further 36% was classed as dangerous. Cadmium was more abundant in clay soils than in sandy soils. Bioavailable Cd in quaternary sediments was significantly affected by the total Cd, and labile Cd accounted for more than half of the total Cd. Changes in pH mainly affected bioavailable Cd rather than total Cd, affecting the overall bioavailability of Cd. Conclusions: Nansha soils are commonly and seriously contaminated with Cd. An appropriate remediation treatment approach should be used to reduce Cd bioavailability. Furthermore, planting structures in farmland should be adjusted to avoid the impact of heavy metals on human health.

6.
J Plant Res ; 132(6): 857-866, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31493170

RESUMO

Minghuai 1 (MH1) is a yam (Dioscorea alata) cultivar with high tolerance to flooding but sensitivity to chilling. MH1 responded differently to chilling and flooding according to various physiological parameters and antioxidant enzymes. Flooding led to an increase in ascorbate peroxidase (APX) activity in both roots and leaves, while chilling did not affect APX activity. The full length DaAPX ORF sequence from MH1 (750 bp) was then cloned. Phylogenetic analysis showed that plant cytosolic APXs into four major clusters and DaAPX was closely related to Oncidium. The DaAPX gene driven by a 35S promoter was transferred into Arabidopsis. The gene expression and enzyme activity of APX in the DaAPX transgenic lines 1-3 were significantly higher than in wild type (WT) plants. Compared to WT plants, seedling growth characteristics were significantly better in all transgenic lines under chilling, flooding, and oxidative stresses, indicating that the overexpression of DaAPX in Arabidopsis enhanced tolerance to several abiotic stresses. MH1 plants supplied with H2O2 presented an increase in the activity of APX leading to enhanced tolerance to chilling. Functional characterization of the APX gene should improve our understanding of the chilling- and flood-response mechanism in the yam.

8.
Cancer Res ; 79(22): 5812-5825, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31362929

RESUMO

Activating mutations in BRAF, a key mediator of RAS signaling, are present in approximately 50% of melanoma patients. Pharmacologic inhibition of BRAF or the downstream MAP kinase MEK is highly effective in treating BRAF-mutant melanoma. In contrast, RAS pathway inhibitors have been less effective in treating epithelial malignancies, such as lung cancer. Here, we show that treatment of melanoma patients with BRAF and MEK inhibitors (MEKi) activated tumor NF-κB activity. MEKi potentiated the response to TNFα, a potent activator of NF-κB. In both melanoma and lung cancer cells, MEKi increased cell-surface expression of TNFα receptor 1 (TNFR1), which enhanced NF-κB activation and augmented expression of genes regulated by TNFα and IFNγ. Screening of 289 targeted agents for the ability to increase TNFα and IFNγ target gene expression demonstrated that this was a general activity of inhibitors of MEK and ERK kinases. Treatment with MEKi led to acquisition of a novel vulnerability to TNFα and IFNγ-induced apoptosis in lung cancer cells that were refractory to MEKi killing and augmented cell-cycle arrest. Abolishing the expression of TNFR1 on lung cancer cells impaired the antitumor efficacy of MEKi, whereas the administration of TNFα and IFNγ in MEKi-treated mice enhanced the antitumor response. Furthermore, immunotherapeutics known to induce expression of these cytokines synergized with MEKi in eradicating tumors. These findings define a novel cytokine response modulatory function of MEKi that can be therapeutically exploited. SIGNIFICANCE: Lung cancer cells are rendered sensitive to MEK inhibitors by TNFα and IFNγ, providing a strong mechanistic rationale for combining immunotherapeutics, such as checkpoint blockers, with MEK inhibitor therapy for lung cancer.See related commentary by Havel, p. 5699.

9.
Nat Commun ; 10(1): 3578, 2019 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-31395880

RESUMO

How genomic and transcriptomic alterations affect the functional proteome in lung cancer is not fully understood. Here, we integrate DNA copy number, somatic mutations, RNA-sequencing, and expression proteomics in a cohort of 108 squamous cell lung cancer (SCC) patients. We identify three proteomic subtypes, two of which (Inflamed, Redox) comprise 87% of tumors. The Inflamed subtype is enriched with neutrophils, B-cells, and monocytes and expresses more PD-1. Redox tumours are enriched for oxidation-reduction and glutathione pathways and harbor more NFE2L2/KEAP1 alterations and copy gain in the 3q2 locus. Proteomic subtypes are not associated with patient survival. However, B-cell-rich tertiary lymph node structures, more common in Inflamed, are associated with better survival. We identify metabolic vulnerabilities (TP63, PSAT1, and TFRC) in Redox. Our work provides a powerful resource for lung SCC biology and suggests therapeutic opportunities based on redox metabolism and immune cell infiltrates.

10.
Clin Cancer Res ; 25(22): 6623-6632, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31409616

RESUMO

PURPOSE: Histone deacetylase inhibitors (HDACi) enhance tumor immunogenicity through several mechanisms and may improve response to immune checkpoint inhibitors (ICIs). In a phase I/Ib trial, we tested the oral HDACi vorinostat combined with the programmed cell death protein 1 inhibitor pembrolizumab in advanced/metastatic non-small cell lung cancer. PATIENTS AND METHODS: Patients received intravenous pembrolizumab (200 mg every 3 weeks) plus oral vorinostat (200 or 400 mg/day). Primary endpoint was safety/tolerability. Secondary endpoints included response rate, progression-free survival, disease control rate (DCR), and overall survival. Tumor gene expression changes, T-cell density, and myeloid cell levels were studied in serial tissue specimens. RESULTS: Thirty-three patients were treated (13 in phase I, 20 in phase Ib). In phase I, both ICI-naïve and ICI-pretreated patients were enrolled to determine dose-limiting toxicities (DLT). No DLTs were observed, and the recommended phase I dose was pembrolizumab 200 mg and vorinostat 400 mg. Any-grade adverse events were mainly fatigue (33%) and nausea/vomiting (27%). Of six ICI-naïve and 24 ICI-pretreated patients evaluable for response, four (13%) had partial response [two confirmed, one unconfirmed with subsequent prolonged stable disease (SD), one unconfirmed with subsequent progressive disease (PD)], 16 (53%) had SD, and 10 (33%) had PD for a DCR of 67%. In the ICI-pretreated cohort, three patients (one confirmed, two unconfirmed) had partial response and 10 had SD. Pretreatment CD8+ T-cell presence in tumor stromal regions was associated with treatment benefit. CONCLUSIONS: Pembrolizumab plus vorinostat was well tolerated and demonstrated preliminary antitumor activity despite progression on prior ICI treatment.

11.
Environ Sci Pollut Res Int ; 26(29): 30055-30068, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31414390

RESUMO

Long-term mining activities reshape the hydraulic and hydrochemical field, and threaten the safe use of groundwater and ecosystem balance. Here, we concluded the evolution characteristics and processes of karst groundwater system based on the water level and hydrochemistry data of the Carboniferous and Devonian aquifer in Maoping lead-zinc deposit, a representative in southwestern China. After concentrated mining lasting for nearly three decades, this mining area has generated a huge depression cone coupled with decreased level, changed flowpath, massive drainage, and direct hydraulic connection across the aquiclude. However, these two sets of karst aquifers exhibited distinct hydrochemical evolution patterns in particular with respect to sulfate. SO42- and the total dissolved solids (TDS) increased slightly in the Carboniferous aquifer and maintained the hydrochemical type of HCO3 and HCO3·SO4. While, SO42- and TDS in the Devonian aquifer decreased drastically, and the hydrochemical type was converted from SO4 and SO4·HCO3 to HCO3 and HCO3·SO4. Before concentrated mining, pyrite oxidation and dissolution of carbonate minerals mutually promoted each other in sluggish groundwater flow, then generated abnormally high concentrations of SO42-, Ca2+, and Mg2+ in Devonian karst aquifer, causing an illusion of saturation state of gypsum dissolution. At present, SO42- is mainly derived from pyrite oxidation indicated by sulfur isotope except deep groundwater contributed by gypsum dissolution. Groundwater quality in the Devonian aquifer was improved together by the dilution of northern shallow groundwater from the external Carboniferous aquifer and upward recharge of southern deep groundwater itself. Results of principal component analysis (PCA) verified the different recharge resources and mixing process resulted from continuous mining activities, which were the driving forces of hydrochemical evolution. Qualitatively speaking, the disturbing degree of the hydrodynamic field was consistent with the variation degree of hydrochemical filed. This research shed light upon the groundwater system and its evolution induced by intensive mining, which will benefit the future mining project.

12.
Int J Chron Obstruct Pulmon Dis ; 14: 1009-1018, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190786

RESUMO

Dysregulated lipid metabolism plays crucial roles in various diseases, including diabetes mellitus, cancer, and neurodegeneration. Recent studies suggest that alterations in major lipid metabolic pathways contribute to pathogenesis of lung diseases, including chronic obstructive pulmonary disease (COPD). These changes allow lung tissue to meet the energy needs and trigger anabolic pathways that initiate the synthesis of active molecules directly involved in the inflammation. In this review, we summarize the changes of catabolism and anabolism of lipids, lipid molecules including lipid mediators, lipid synthesis transcription factors, cholesterol, and phospholipids, and how those lipid molecules participate in the initiation and resolution of inflammation in COPD.

13.
Autophagy ; : 1-16, 2019 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-31203721

RESUMO

Particulate matter (PM) is able to induce airway epithelial injury, while the detailed mechanisms remain unclear. Here we demonstrated that PM exposure inactivated MTOR (mechanistic target of rapamycin kinase), enhanced macroautophagy/autophagy, and impaired lysosomal activity in HBE (human bronchial epithelial) cells and in mouse airway epithelium. Genetic or pharmaceutical inhibition of MTOR significantly enhanced, while inhibition of autophagy attenuated, PM-induced IL6 expression in HBE cells. Consistently, club-cell-specific deletion of Mtor aggravated, whereas loss of Atg5 in bronchial epithelium reduced, PM-induced airway inflammation. Interestingly, the augmented inflammatory responses caused by MTOR deficiency were markedly attenuated by blockage of downstream autophagy both in vitro and in vivo. Mechanistically, the dysregulation of MTOR-autophagy signaling was partially dependent on activation of upstream TSC2, and interacted with the TLR4-MYD88 to orchestrate the downstream NFKB activity and to regulate the production of inflammatory cytokines in airway epithelium. Moreover, inhibition of autophagy reduced the expression of EPS15 and the subsequent endocytosis of PM. Taken together, the present study provides a mechanistic explanation for how airway epithelium localized MTOR-autophagy axis regulates PM-induced airway injury, suggesting that activation of MTOR and/or suppression of autophagy in local airway might be effective therapeutic strategies for PM-related airway disorders. Abbreviations: ACTB: actin beta; AKT: AKT serine/threonine kinase; ALI: air liquid interface; AP2: adaptor related protein complex 2; ATG: autophagy related; BALF: bronchoalveolar lavage fluid; COPD: chronic obstructive pulmonary disease; CXCL: C-X-C motif chemokine ligand; DOX: doxycycline; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; EPS15: epidermal growth factor receptor pathway substrate 15; HBE: human bronchial epithelial; H&E: hematoxylin & eosin; IKK: IKB kinase; IL: interleukin; LAMP2: lysosomal-associated membrane protein 2; LPS: lipopolysaccharide; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MTEC: mouse tracheal epithelial cells; MTOR: mechanistic target of rapamycin kinase; MYD88: MYD88 innate immune signal transduction adaptor; NFKB: nuclear factor of kappa B; NFKBIA: NFKB inhibitor alpha; PM: particulate matter; PtdIns3K: phosphatidylinositol 3-kinase; Rapa: rapamycin; RELA: RELA proto-oncogene, NFKB subunit; SCGB1A1: secretoglobin family 1A member 1; siRNA: small interfering RNAs; SQSTM1: sequestosome 1; TEM: transmission electronic microscopy; TLR4: toll like receptor 4; TSC2: TSC complex subunit 2.

14.
Acta Biochim Biophys Sin (Shanghai) ; 51(6): 598-606, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31058289

RESUMO

The purpose of this study was to investigate the expression of microRNA-202 (miR-202) and its role in colorectal cancer (CRC) in vivo and in vitro. We examined the expression of miR-202 in CRC tissues by quantitative real-time PCR (qRT-PCR) assay. Lentiviral vectors were constructed to overexpress or inhibit the expression of miR-202 in the CRC cell lines HCT116 and SW480 to determine its effects on cell invasion and proliferation. We found that overexpression of miR-202 significantly inhibited the proliferation and invasion of HCT116 cells. MiRNA target gene prediction, dual luciferase assay, and western blot analysis demonstrated that miR-202 regulated ubiquitin-like with PHD and RING finger domain 1 (UHRF1) expression in both cell lines. The effect of miR-202 on cell proliferation and invasion was partially reversed by activating the expression of UHRF1. Furthermore, miR-202 induced tumor formation in HCT116 xenograft BALB/c nude mice. Mice vaccinated with miR-202-overexpressing cells had smaller tumors and lower UHRF1 expression than the control group. These results indicate the possibility that miR-202 is under-expressed in CRC tissues, and that miR-202 inhibits the proliferation and invasion of CRC via targeting UHRF1. MiR-202 is a potential therapeutic target for CRC.

15.
Proc Natl Acad Sci U S A ; 116(19): 9230-9238, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31004056

RESUMO

Metal oxide (MO) semiconductor thin films prepared from solution typically require multiple hours of thermal annealing to achieve optimal lattice densification, efficient charge transport, and stable device operation, presenting a major barrier to roll-to-roll manufacturing. Here, we report a highly efficient, cofuel-assisted scalable combustion blade-coating (CBC) process for MO film growth, which involves introducing both a fluorinated fuel and a preannealing step to remove deleterious organic contaminants and promote complete combustion. Ultrafast reaction and metal-oxygen-metal (M-O-M) lattice condensation then occur within 10-60 s at 200-350 °C for representative MO semiconductor [indium oxide (In2O3), indium-zinc oxide (IZO), indium-gallium-zinc oxide (IGZO)] and dielectric [aluminum oxide (Al2O3)] films. Thus, wafer-scale CBC fabrication of IGZO-Al2O3 thin-film transistors (TFTs) (60-s annealing) with field-effect mobilities as high as ∼25 cm2 V-1 s-1 and negligible threshold voltage deterioration in a demanding 4,000-s bias stress test are realized. Combined with polymer dielectrics, the CBC-derived IGZO TFTs on polyimide substrates exhibit high flexibility when bent to a 3-mm radius, with performance bending stability over 1,000 cycles.

16.
Cancer Epidemiol Biomarkers Prev ; 28(7): 1117-1126, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948450

RESUMO

BACKGROUND: Germline DNA copy number variation (CNV) is a ubiquitous source of genetic variation and remains largely unexplored in association with epithelial ovarian cancer (EOC) risk. METHODS: CNV was quantified in the DNA of approximately 3,500 cases and controls genotyped with the Illumina 610k and HumanOmni2.5M arrays. We performed a genome-wide association study of common (>1%) CNV regions (CNVRs) with EOC and high-grade serous (HGSOC) risk and, using The Cancer Genome Atlas (TCGA), performed in silico analyses of tumor-gene expression. RESULTS: Three CNVRs were associated (P < 0.01) with EOC risk: two large (∼100 kb) regions within the 610k set and one small (<5 kb) region with the higher resolution 2.5M data. Large CNVRs included a duplication at LILRA6 (OR = 2.57; P = 0.001) and a deletion at CYP2A7 (OR = 1.90; P = 0.007) that were strongly associated with HGSOC risk (OR = 3.02; P = 8.98 × 10-5). Somatic CYP2A7 alterations correlated with EGLN2 expression in tumors (P = 2.94 × 10-47). An intronic ERBB4/HER4 deletion was associated with reduced EOC risk (OR = 0.33; P = 9.5 × 10-2), and somatic deletions correlated with ERBB4 downregulation (P = 7.05 × 10-5). Five CNVRs were associated with HGSOC, including two reduced-risk deletions: one at 1p36.33 (OR = 0.28; P = 0.001) that correlated with lower CDKIIA expression in TCGA tumors (P = 2.7 × 10-7), and another at 8p21.2 (OR = 0.52; P = 0.002) that was present somatically where it correlated with lower GNRH1 expression (P = 5.9 × 10-5). CONCLUSIONS: Though CNV appears to not contribute largely to EOC susceptibility, a number of low-to-common frequency variants may influence the risk of EOC and tumor-gene expression. IMPACT: Further research on CNV and EOC susceptibility is warranted, particularly with CNVs estimated from high-density arrays.

17.
Proc Inst Mech Eng H ; 233(6): 621-635, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30922161

RESUMO

Recently, the failure rate of fracture fixation to fractured bone has increased. Mechanical and thermal damage to the bone, which influences the contact area and cell growth between the bone and the screw, is the primary reason for fixation failure. However, research has mainly focused on force and temperature in bone drilling. In this study, the characteristics of hole edges, microcracks, empty lacunae, and osteon necrosis were investigated as viewed in the transverse and longitudinal sections after drilling. Drilling force and temperature were also recorded for comparing the relationship with mechanical and thermal damage. Experiments were conducted in vivo using five different drill geometries under the same drilling parameters. Characteristics of the hole wall were detected using computed tomography. Microcracks and necrosis were analyzed using the pathological sectioning method. The maximum microcrack was approximately 3000 and 1400 µm in the transverse section and longitudinal section, respectively, which were much larger than those observed in previous studies. Empty lacuna and osteon necrosis, starting from the Haversian canal, were also found. The drill bit geometry, chisel edge, flute number, edges, and steps had a strong effect on bone damage, particularly the chisel edge. The standard and classic surgical drill caused the greatest surface damage and necrosis of the five drill bit geometries studied. The microstructural features including osteons and matrix played an important role in numbers and length of microcracks and necrosis. More microcracks were generated in the transverse direction, while a greater length of the empty lacuna was generated in the longitudinal direction under the same drilling parameters. Microcracks mainly propagated in a straight manner in and parallel to the interstitial bone matrix and cement line. Drilling forces were not directly correlated with bone damage; thus, hole performance should be considered to evaluate the superiority and inferiority of drill bits rather than the drill force alone.


Assuntos
Osso Cortical/cirurgia , Fixação de Fratura/efeitos adversos , Fenômenos Mecânicos , Temperatura Ambiente , Animais , Osso Cortical/diagnóstico por imagem , Osso Cortical/patologia , Fêmur/diagnóstico por imagem , Fêmur/patologia , Fêmur/cirurgia , Fixação de Fratura/instrumentação , Masculino , Necrose/etiologia , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/patologia , Rádio (Anatomia)/cirurgia , Suínos , Tomografia Computadorizada por Raios X
18.
Cancer Res ; 79(7): 1263-1273, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30894373

RESUMO

Recent work points to a lack of diversity in genomics studies from genome-wide association studies to somatic (tumor) genome analyses. Yet, population-specific genetic variation has been shown to contribute to health disparities in cancer risk and outcomes. Immortalized cancer cell lines are widely used in cancer research, from mechanistic studies to drug screening. Larger collections of cancer cell lines better represent the genomic heterogeneity found in primary tumors. Yet, the genetic ancestral origin of cancer cell lines is rarely acknowledged and often unknown. Using genome-wide genotyping data from 1,393 cancer cell lines from the Catalogue of Somatic Mutations in Cancer (COSMIC) and Cancer Cell Line Encyclopedia (CCLE), we estimated the genetic ancestral origin for each cell line. Our data indicate that cancer cell line collections are not representative of the diverse ancestry and admixture characterizing human populations. We discuss the implications of genetic ancestry and diversity of cellular models for cancer research and present an interactive tool, Estimated Cell Line Ancestry (ECLA), where ancestry can be visualized with reference populations of the 1000 Genomes Project. Cancer researchers can use this resource to identify cell line models for their studies by taking ancestral origins into consideration.

19.
Soft Matter ; 15(10): 2245-2259, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30762056

RESUMO

Entropy production during the process of thermal phase-separation of multiphase flows is investigated by means of a discrete Boltzmann kinetic model. The entropy production rate is found to increase during the spinodal decomposition stage and to decrease during the domain growth stage, attaining its maximum at the crossover between the two. Such behaviour provides a natural criterion to identify and discriminate between the two regimes. Furthermore, the effects of heat conductivity, viscosity and surface tension on the entropy production rate are investigated by systematically probing the interplay between non-equilibrium energy and momentum fluxes. It is found that the entropy production rate due to energy fluxes is an increasing function of the Prandtl number, while the momentum fluxes exhibit an opposite trend. On the other hand, both contributions show an increasing trend with surface tension. The present analysis inscribes within the general framework of non-equilibrium thermodynamics and consequently it is expected to be relevant to a broad class of soft-flowing systems far from mechanical and thermal equilibrium.

20.
Artigo em Inglês | MEDLINE | ID: mdl-30717418

RESUMO

Slag heaps are formed by mining waste materials, and the improper treatment of leachate from such heaps can threaten nearby aquifers. The Zhehai slag heap in Yunnan Province, China, contains 2.7 million tons of zinc and cadmium slag, and is considered a heavy metal source threatening the local groundwater safety, however, the severity of contamination remains unknown. In this study, numerical modeling was used to predict the groundwater flow and contaminant transport in this area based on field data. The results show that the atmospheric precipitation infiltration recharge at the top of the heap is 81.8 m³/d, accounting for 93.76% of total infiltration. The south and east sides of the area are the main outflow channels for contaminants, accounting for 93.25% of the total discharge around the heap. To reduce aquifer contamination, an in situ system involving a "controlling the source, 'breaking' the path, and intercepting the flow" (CSBPIF) strategy is established. The results indicate that the system performs well because it not only decreases the flow velocity but also reduces the concentrations of contaminants adsorbed by clay media. Moreover, the equivalent bottom liner thicknesses of the clay layers were calculated to improve the applicability of the CSBPIF system. Compared with ex situ disposal, this scheme provides an economic and effective solution and can be used to prevent and control groundwater pollution in China.


Assuntos
Metais Pesados/química , Eliminação de Resíduos/métodos , Poluentes Químicos da Água/química , Poluição da Água/prevenção & controle , Adsorção , China , Água Subterrânea/química , Metais Pesados/análise , Mineração , Modelos Químicos , Movimentos da Água , Poluentes Químicos da Água/análise
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