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1.
J Environ Manage ; 306: 114467, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35026712

RESUMO

The adsorption of benzene on soils is specifically associated with its migration and transformation. Although previous studies have proved that the adsorption of benzene is affected by various factors, studies simultaneously considering the effects of multiple factors are rare. This study aimed to identify the qualitative and quantitative relationships between multiple influential factors and the adsorption capacity of benzene (BC). Batch adsorption experiments considering different influential factors, including initial concentration (IC), pH, temperature (T), ion strength (IS) and organic matter content (OMC), were conducted in three kinds of soils collected in a chemical industry park. The correlation analysis between different influential factors and BC was carried out based on the experimental data. The artificial neural network (ANN) was applied to predict BC. The results showed that BC increased with the increase of T. As the pH increased, BCs on silty loam and loam increased, while that on sandy loam decreased. Besides, BCs on silty loam and loam raised with increasing OMC, while that on sandy loam remained unchanged. BCs on all three kinds of soils attained their peaks when IS was small and then become stable with an increase in IS. The sequence of correlation between BC and influential factors is listed as IC > OMC > T > IS > pH for silty loam, OMC > IC > T > IS > pH for loam and IC > T > IS > pH > OMC for sandy loam. ANN analysis showed satisfactory accuracy in predicting BC under different influential factors. These results help us understand the important factors affecting benzene adsorption and provide a tool to get the adsorption information easily in complex site conditions.


Assuntos
Poluentes do Solo , Solo , Adsorção , Benzeno , Redes Neurais de Computação , Poluentes do Solo/análise
2.
J Cell Physiol ; 234(9): 15450-15458, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30693509

RESUMO

Hindrance to successful therapy of colon cancer is generally characterized with reduced potency of a single drug at the active site of cancer, poor drug release, and most importantly, potential toxic side effects of the drug resulting in cytotoxicity. Therefore, we investigated combinatorial drug micelles which are a potent combination of twin anticancer drugs (indomethacin and piroxicam, IND+PIR mc) for successful therapeutics of colon cancer. The novel combinatorial micelles showed improved drug encapsulation efficiency, an in vitro burst release of the dual drugs, increased cytocompatibility and increased efficacy in tumor reduction (weight and volume) than in single drug micelles (IND mc or PIR mc). The improved IND+PIR MC were to have small size 150.36 ± 15.13 nm (to avoid being taken up by liver, lungs or kidney or to sediment) with poly dispersity index (PDI) value at 0.24 ± 0.01. The PDI values suggest homogenous distribution. Encapsulation efficiency of IND+PIR mc was calculated at 86%. IND+PR mc had improved biocompatibility as demonstrated by CRL-1459™ (normal colon) cell line than IND mc or PIR mc individually. The in vivo studies in mice model clearly depict that subcutaneous tumor weight reduced by almost 75% and volume reduced drastically by 55% on administration of IND+PIR mc than IND mc or PIR mc. Furthermore, fewer side effects were found with IND+PIR mc. To conclude, IND+PIR mc may be a potential anticancer strategy to be explored more in the future.

3.
Biochem Biophys Res Commun ; 514(4): 1108-1114, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31101340

RESUMO

L-amino acids represent the most common amino acid form, most notably as protein residues, whereas D-amino acids, despite their rare occurrence, play significant roles in many biological processes. Amino acid racemases are enzymes that catalyze the interconversion of L- and/or D-amino acids. McyF is a pyridoxal 5'-phosphate (PLP) independent amino acid racemase that produces the substrate D-aspartate for the biosynthesis of microcystin in the cyanobacterium Microcystis aeruginosa PCC7806. Here we report the crystal structures of McyF in complex with citrate, L-Asp and D-Asp at 2.35, 2.63 and 2.80 Å, respectively. Structural analyses indicate that McyF and homologs possess highly conserved residues involved in substrate binding and catalysis. In addition, residues Cys87 and Cys195 were clearly assigned to the key catalytic residues of "two bases" that deprotonate D-Asp and L-Asp in a reaction independent of PLP. Further site-directed mutagenesis combined with enzymatic assays revealed that Glu197 also participates in the catalytic reaction. In addition, activity assays proved that McyF could also catalyze the interconversion of L-MeAsp between D-MeAsp, the precursor of another microcystin isoform. These findings provide structural insights into the catalytic mechanism of aspartate racemase and microcystin biosynthesis.


Assuntos
Isomerases de Aminoácido/metabolismo , Microcystis/enzimologia , Biocatálise , Cristalografia por Raios X , Modelos Moleculares , Especificidade por Substrato
4.
Cell Physiol Biochem ; 42(3): 1202-1212, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28683453

RESUMO

BACKGROUND/AIMS: This study aims to investigate the role of circular antisense non-coding RNA at the INK4 locus (cANRIL) in the inflammatory response of vascular endothelial cells (ECs) in a rat model of coronary atherosclerosis (AS). A rat model of AS was established with rats that were injected with a large dose of vitamin D3 and fed a high-fat diet. METHODS: Sixty Wistar rats were randomly assigned into control, model, empty vector, over-expressed cANRIL and low-expressed cANRIL groups (12 rats in each group). Sixteen weeks later, the ultrastructure of their coronary arteries was observed via transmission electron microscopy. Rat serum lipid levels were analyzed using an automatic biochemical analyzer, and their atherogenic index (AI) values were calculated. Hematoxylin and eosin staining was used to observe the endothelial morphology of rats. Additionally, rat EC apoptosis was tested via a TUNEL assay. Enzyme-linked immunosorbent assays (ELISAs) were applied to measure serum levels of interleukin-1 (IL-1), IL-6, matrix metalloproteinase-9 (MMP-9) and C-reactive protein (CRP). The cANRIL, Bax, bcl-2 and caspase-3 mRNA expression levels were measured with a quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression levels of Bax, bcl-2 and caspase-3 were detected using immunohistochemistry. RESULTS: In the control group, ECs were closely arranged with normal structures, and there was no proliferation. In the model, empty vector and over-expressed cANRIL groups, some cells were not present, and atherosclerotic plaques and thrombi appeared. However, in the under-expressed cANRIL group, the cells had a normal structure. Compared with the model and empty vector groups, the levels of total cholesterol (CHOL), triglycerides (TGs), low density lipoprotein (LDL), IL-1, IL-6, MMP-9, CRP, cANRIL, Bax, and caspase-3, AI values, and rates of EC apoptosis decreased in the low-expressed cANRIL group, while HDL (high density lipoprotein) levels and mRNA and protein expression levels of bcl-2 were increased. The changes in expression levels in the over-expressed cANRIL group were the opposite of those in the low-expressed cANRIL group. CONCLUSIONS: Our study provides evidence that reduced cANRIL expression could prevent coronary AS by reducing vascular EC apoptosis and inflammatory factor expression.


Assuntos
Doença da Artéria Coronariana/imunologia , Doença da Artéria Coronariana/patologia , Células Endoteliais/imunologia , Células Endoteliais/patologia , RNA Longo não Codificante/imunologia , Animais , Apoptose , Proteína C-Reativa/análise , Proteína C-Reativa/imunologia , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/genética , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Regulação da Expressão Gênica , Inflamação/sangue , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Interleucina-1/sangue , Interleucina-1/imunologia , Interleucina-6/sangue , Interleucina-6/imunologia , Masculino , Metaloproteinase 9 da Matriz/sangue , Metaloproteinase 9 da Matriz/imunologia , RNA Longo não Codificante/genética , Ratos Wistar
5.
Nucleic Acids Res ; 42(6): 3607-22, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24423874

RESUMO

In prostate cancer, androgen receptor (AR) binding and androgen-responsive gene expression are defined by hormone-independent binding patterns of the pioneer factors FoxA1 and GATA2. Insufficient evidence of the mechanisms by which GATA2 contributes to this process precludes complete understanding of a key determinant of tissue-specific AR activity. Our observations suggest that GATA2 facilitates androgen-responsive gene expression by three distinct modes of action. By occupying novel binding sites within the AR gene locus, GATA2 positively regulates AR expression before and after androgen stimulation. Additionally, GATA2 engages AR target gene enhancers prior to hormone stimulation, producing an active and accessible chromatin environment via recruitment of the histone acetyltransferase p300. Finally, GATA2 functions in establishing and/or sustaining basal locus looping by recruiting the Mediator subunit MED1 in the absence of androgen. These mechanisms may contribute to the generally positive role of GATA2 in defining AR genome-wide binding patterns that determine androgen-responsive gene expression profiles. We also find that GATA2 and FoxA1 exhibit both independent and codependent co-occupancy of AR target gene enhancers. Identifying these determinants of AR transcriptional activity may provide a foundation for the development of future prostate cancer therapeutics that target pioneer factor function.


Assuntos
Fator de Transcrição GATA2/metabolismo , Regulação Neoplásica da Expressão Gênica , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Neoplasias da Próstata/genética , Receptores Androgênicos/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Cromatina/química , Cromatina/metabolismo , Elementos Facilitadores Genéticos , Genoma Humano , Humanos , Masculino , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/genética
6.
EMBO J ; 30(12): 2405-19, 2011 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-21556051

RESUMO

The UBE2C oncogene is overexpressed in many types of solid tumours including the lethal castration-resistant prostate cancer (CRPC). The underlying mechanisms causing UBE2C gene overexpression in CRPC are not fully understood. Here, we show that CRPC-specific enhancers drive UBE2C overexpression in both AR-negative and -positive CRPC cells. We further show that co-activator MED1 recruitment to the UBE2C enhancers is required for long-range UBE2C enhancer/promoter interactions. Importantly, we find that the molecular mechanism underlying MED1-mediated chromatin looping involves PI3K/AKT phosphorylated MED1-mediated recruitment of FoxA1, RNA polymerase II and TATA binding protein and their subsequent interactions at the UBE2C locus. MED1 phosphorylation leads to UBE2C locus looping, UBE2C gene expression and cell growth. Our results not only define a causal role of a post-translational modification (phosphorylation) of a co-activator (MED1) in forming or sustaining an active chromatin structure, but also suggest that development of specific therapies for CRPC should take account of targeting phosphorylated MED1.


Assuntos
Proliferação de Células , Elementos Facilitadores Genéticos/genética , Loci Gênicos/genética , Subunidade 1 do Complexo Mediador/metabolismo , Conformação de Ácido Nucleico , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Enzimas de Conjugação de Ubiquitina/genética , Linhagem Celular Tumoral , Cromatina/genética , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Masculino , Subunidade 1 do Complexo Mediador/fisiologia , Fosforilação/genética , Neoplasias da Próstata/mortalidade , Receptores Androgênicos/biossíntese , Receptores Androgênicos/genética , Enzimas de Conjugação de Ubiquitina/biossíntese , Regulação para Cima/genética
7.
Sci Rep ; 14(1): 10435, 2024 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-38714737

RESUMO

During takeoff and landing, birds bounce and grab with their legs and feet. In this paper,the lower limb structure of the bionic bird is designed with reference to the function of jumping and grasping, and the PID algorithm based on the development module of stm32 development board is used to speed control the lower limb driving element, so that the motor and the bishaft steering gear move with the rate change of sine wave. According to the speed of grasping response time and the size of grasping force, the structure of the bionic bird paw is designed. Based on the photosensitive sensor fixed in the geometric center of the foot, the grasping action of the lower limb mechanism is intelligently controlled. Finally, the kinematic verification of the lower limb structure is carried out by ADAMS. Experiments show that the foot structure with four toes and three toes is more conducive to maintaining the stability of the body while realizing the fast grasping function. In addition, it can effectively improve the push-lift ratio of the bionic ornithopter by adjusting the sinusoidal waveform rate of the motor speed.


Assuntos
Biônica , Aves , Animais , Aves/fisiologia , Fenômenos Biomecânicos , Algoritmos , Desenho de Equipamento , Voo Animal/fisiologia
8.
Heliyon ; 10(2): e24940, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38312617

RESUMO

This study systematically optimized the key operating parameters and interpreted their effecting mechanisms in a flow-electrode capacitive deionization (FCDI) system. The optimal voltage, activated carbon electrode content, electrolyte concentration, feedwater flowrate, and electrode flowrate for desalinating low salinity feedwater (1.0 g L-1 NaCl) were determined to be 1.8 V, 2.0 wt%, 10.0 g L-1, 80 mL min-1, and 60 mL min-1, respectively. The variations of the above parameters can affect the system conductivity, the thickness and stability of the electric double layers, and/or the degree of concentration polarization, thereby influencing the desalination performance. Moreover, a sensitivity analysis identified the operating voltage as the dominant parameter with the most significant influence on the FCDI system. Subsequently, a long-term operation was carried out under single-pass mode. The results showed that the lab-scale FCDI system was able to constantly maintain the desalination efficiency of 1.0 g L-1 feedwater (NaCl) at 40-60 % for multiple operating cycles. Over 99.8 % of electrode material regeneration and desalination efficiency recovery was able to be obtained during a 60-h operation, demonstrating that the FCDI system showed strong stability and long-term operation potential.

9.
PLoS One ; 19(4): e0297936, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38578717

RESUMO

Aiming at the problems of high vibration and high noise in gear transmission systems, a model of gear with staggered tooth phase structure(GSTPS) for reducing vibration is proposed. Without changing the overall structure of the gear transmission system, the purpose of reducing mesh stiffness fluctuations is achieved by staggering adjacent gears at a certain angle along the axis, thereby the vibration of the gear transmission system could be reduced. The characterization method of time-varying mesh stiffness of the GSTPS is studied. Then, the impact of different staggered tooth phases(STP) on reducing vibration of the transmission system are researched, and the basis for selecting the optimal STP are obtained. The experimental platform for reducing vibration with STP is established. And some experimental studies were conducted to validate the theoretical model.


Assuntos
Modalidades de Fisioterapia , Vibração
10.
ISA Trans ; 146: 29-41, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38104021

RESUMO

The uncertainty in mobile robot greatly affects control accuracy. This makes it difficult to apply to more rigorous high-precision engineering fields. Therefore, the fuzzy set theory is introduced to describe the uncertainty. Based on that, the fuzzy mobile robot system is established. The virtual speed controller using backstepping method is designed. Then, a robust control method is proposed to guarantee the uniform boundedness and uniform ultimate boundedness of the controlled system. Furthermore, the balance optimization problem of the performance and cost of the controlled system is explored. By minimizing the performance index containing fuzzy numbers, the optimal control parameter is obtained. Compared with the linear quadratic regulator algorithm, which is the representative optimal robust controller, the proposed control method and optimization strategy based on fuzzy set theory are verified to be effective. The control accuracy is further improved.

11.
J Biol Chem ; 287(21): 17109-17119, 2012 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-22451655

RESUMO

S100 proteins have been implicated in tumorigenesis and metastasis. As a member of S100 proteins, the role of S100A14 in carcinogenesis has not been fully understood. Here, we showed that ectopic overexpression of S100A14 promotes motility and invasiveness of esophageal squamous cell carcinoma cells. We investigated the underlying mechanisms and found that the expression of matrix metalloproteinase (MMP)-2 is obviously increased after S100A14 gene overexpression. Inhibition of MMP2 by a specific MMP2 inhibitor at least partly reversed the invasive phenotype of cells overexpressing S100A14. By serendipity, we found that S100A14 could affect p53 transactivity and stability. Thus, we further investigated whether the effect of MMP2 by S100A14 is dependent on p53. A series of biochemical assays showed that S100A14 requires functional p53 to affect MMP2 transcription, and p53 potently transrepresses the expression of MMP2. Finally, RT-quantitative PCR analysis of human breast cancer specimens showed a significant correlation between S100A14 mRNA expression and MMP2 mRNA expression in cases with wild-type p53 but not in cases with mutant p53. Collectively, our data strongly suggest that S100A14 promotes cell motility and invasiveness by regulating the expression and function of MMP2 in a p53-dependent manner.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Carcinoma de Células Escamosas/metabolismo , Neoplasias Esofágicas/metabolismo , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Metaloproteinase 2 da Matriz/biossíntese , Proteína Supressora de Tumor p53/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Proteínas de Ligação ao Cálcio/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Metaloproteinase 2 da Matriz/genética , Invasividade Neoplásica , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Proteína Supressora de Tumor p53/genética
12.
Hum Cell ; 36(5): 1741-1754, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37368192

RESUMO

Hepatocellular carcinoma (HCC) is the most common primary liver cancer worldwide with high mortality rate, and the N6-methyladenosine (m6A) epigenetic modifications have been reported to be closely associated with the pathogenesis of HCC, but the detailed molecular mechanisms by which m6A regulates HCC progression have not been fully delineated. In this study, we evidenced that the m6A methyltransferase-like 3 (METTL3)-mediated m6A modification contributed to HCC aggressiveness through modulating a novel circ_KIAA1429/miR-133a-3p/HMGA2 axis. Specifically, circ_KIAA1429 was aberrantly overexpressed in HCC tissues and cells, and the expression levels of circ_KIAA1429 was positively regulated by METTL3 in HCC cells in a m6A-dependent manner. Then, functional experiments confirmed that deletion of both circ_KIAA1429 and METTL3 suppressed HCC cell proliferation, migration and cell mitosis in vitro and in vivo, and conversely, circ_KIAA1429 overexpression had opposite effects to accelerate HCC development. Furthermore, the downstream mechanisms by which circ_KIAA1429 regulated HCC progression were uncovered, and we validated that silencing of circ_KIAA1429 restrained the malignant phenotypes in HCC cells through modulating the miR-133a-3p/high mobility group AT-hook 2 (HMGA2) axis. To summarize, our study firstly investigated the involvement of a novel METTL3/m6A/circ_KIAA1429/miR-133a-3p/HMGA2 axis in regulating HCC development, which provided novel indicators for HCC diagnosis, therapy and prognosis.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroRNAs , RNA Circular , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias Hepáticas/patologia , Metiltransferases/genética , Metiltransferases/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Circular/genética , Proteína HMGA2/metabolismo
13.
Materials (Basel) ; 16(7)2023 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-37049121

RESUMO

To improve the interfacial compatibility between cement matrix and expanded polystyrene (EPS) in core-shell lightweight aggregates (CSLA), the effects of sodium silicate, polyvinyl acetate (PVA) emulsion, vinyl acetate-ethylene (VAE) emulsion, acrylic acid, and acetic acid on the cement-EPS interface were investigated. The density of the interface was studied by scanning electron microscopy (SEM), and the effect of interfacial agents on the hydration process of cement was studied by the heat of hydration and induction resistivity. The macroscopic properties of the interface of the CSLA were characterized by the "leak-white" rate, drop resistance, and numerical crushing strength. The results show that the sodium silicate densifies the interface by generating hydration products on the EPS surface. At the same time, organic acid enhances the interfacial properties of EPS and cement by increasing the surface roughness, and allowing hydration products to grow in the surface micropores. In terms of the cement hydration process, both interfacial agents delay the cement hydration. Above all, with comprehensive interface properties, "leak-white" rate, and mechanical properties, VAE emulsion and sodium silicate can achieve the best performance with a final crushing resistance of 5.7 MPa, which had a 46% increase compared with the reference group.

14.
Environ Sci Pollut Res Int ; 30(12): 34255-34269, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36508101

RESUMO

Due to the influence of complex regional climate, water quality perturbation factors of lakes in cold regions are complicated, and the uncertainty of each factor needs further study. This study coupled two algorithms (clustering and EM) to establish a water quality uncertainty model of Chagan Lake, a typical cold region lake in China. A BN model containing nine influencing factors (including water temperature (WT), total phosphorus (TP), total nitrogen (TN), etc.) was established and optimized, and sensitivity analysis was also performed. The results indicate that the water quality status of the lake is class III and 27.47% risk of exceeding the standard. The water quality of the lake is more susceptible to disturbance during the freezing period (WT < 1 °C). TP is the most sensitive factor for water quality disturbance in the lake followed by chemical oxygen demand (COD), TN, and fluoride (F). Parameter control result displays, and the multifactor synergistic control scheme could reduce the water quality risk of the lake by 36.47%. This study demonstrates that our proposed method can be used to predict both sudden water quality events and the overall trend of water quality fluctuation, which is important for rapid water quality evaluation and management decisions.


Assuntos
Poluentes Químicos da Água , Qualidade da Água , Monitoramento Ambiental/métodos , Lagos , China , Temperatura , Fósforo/análise , Nitrogênio/análise , Poluentes Químicos da Água/análise , Eutrofização
15.
J Mater Chem B ; 11(22): 5000-5009, 2023 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-37218895

RESUMO

Glucose-sensitive membranes have promising applications in insulin release. Phenylboronic acid (PBA) is an important glucose reporter. Most of PBA-based glucose-sensitive materials are expansion-type, which cannot act as chemical valves in porous membranes for self-regulated insulin release. In this study, a glucose-sensitive membrane with PBA-based contraction-type amphiphilic block copolymer polystyrene-b-poly(N-isopropylacrylamide-co-2-(acrylamido) phenylboronic acid) (PSNB) as chemical valves was constructed through non-solvent induced phase separation (NIPS) method. Due to surface segregation, hydrophobic polystyrene (PS) component can anchor in the membrane matrix to improve the stability of the membrane, and glucose-sensitive hydrophilic poly(N-isopropylacrylamide-co-2-(acrylamido) phenylboronic acid) (PNB) component can expose on the surfaces of the membrane and the channels to provide glucose-sensitivity of the membrane. With increasing the polymer content or chain length of the hydrophilic component, the glucose sensitivity of the membrane was improved. The blend membrane showed glucose-sensitive insulin release behavior in simulated body fluids (SBF) and fetal bovine serum (FBS). The membrane also exhibited good antifouling properties and biocompatibility.


Assuntos
Éter , Insulina , Insulina/química , Poliestirenos , Glucose/química , Polímeros/química , Insulina Regular Humana , Éteres , Sulfonas
16.
Materials (Basel) ; 15(8)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35454446

RESUMO

The use of phase change materials (PCMs) in the construction industry is one of the primary strategies for addressing the building industry's present excessive energy usage. However, since PCMs must be enclosed before being used in construction, their efficiency is limited and their compatibility with concrete is poor. Thus, polyethylene glycol (PEG), a sequence of PCMs that may be put directly into concrete, is the target of this research. The fluidity, mechanical properties, thermal properties, hydration process, and hydration products of PEG-600 cement slurry were examined by TAM, XRD, FTIR, DSC, MALDI, etc., methods in this study. Furthermore, we tested the thermal properties of PEG-800 to confirm that the same depolymerization of PEG occurred in an alkaline environment. When PEG, with a molecular weight of 600 (PEG-600), dose was increased to 10%, both compressive and flexural strength fell by 19% and 18%, respectively. The phase change points of both PEG-600 cement paste and PEG-800 cement paste decreased to 10~15 °C, and the enthalpy of the phase change was about 6 J/g. Additionally, it was discovered that PEG entered the reaction during the hydration step. PEG underwent depolymerization and subsequently formed a complex with Ca2+. However, due to the large dose of PEG used in this investigation, a self-curing effect of PEG in concrete was not seen. The findings of this research suggest a novel use for PCMs: PEG may be directly applied to concrete to fulfill both mechanical and thermal requirements. Additionally, the number of hydration products and phase compositions remained almost constant.

17.
J Hazard Mater ; 432: 128641, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35339835

RESUMO

Colloidal biliquid aphron (CBLA) is a strong density modifier for dense nonaqueous phase liquids (DNAPLs). However, the underlying mechanisms responsible for density modification and displacement is not yet clear. Here, a series of batch column and sandbox experiments were conducted to achieve substantial removal and irreversible density reduction of tetrachloroethylene (PCE). The mass of PCE retained in the column and sandbox was less than 1% under suitable injection conditions, and the density of PCE in the effluent was less than that of water (fluctuated in the range of 0.74-0.96 g/cm3). The displacement process was controlled by the high viscosity ratio of CBLA to PCE (52.3). The emulsified and dissolved phase of PCE formed after reaction with CBLA, and the light nonaqueous phase liquid (LNAPL) phase formed after injecting demulsifier solution. The phase analysis played a significant role in monitoring the changes in concentration and density of PCE. The density-modification displacement technique using CBLA reduced the mass of residual PCE by a factor of 165 compared to surfactant flushing, and there was no risk of downward migration of PCE. This study contributes to a better remediation of entrapped DNAPL in contaminated aquifer.


Assuntos
Água Subterrânea , Tetracloroetileno , Poluentes Químicos da Água , Tensoativos/análise , Tetracloroetileno/análise , Poluentes Químicos da Água/análise
18.
Sci Total Environ ; 810: 151955, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34843788

RESUMO

The widespread use of veterinary antibiotics has led to the significant problem of contamination of livestock wastewater with significant amount of antibiotics. Electrocoagulation (EC) has become a prominent research topic because of the technique's ability to remove antibiotics from livestock wastewater. However, an urgent solution is needed to reduce the high operating costs associated with the process. Therefore, in this study, we developed a positive single pulse current (PSPC)-EC system to remove tetracycline (TC) from synthetic and actual livestock wastewater. Influential factors were investigated, and the optimal PSPC-EC operating parameters were identified as follows: duty ratio = 60%, pH = 4, electrode spacing = 1 cm, current intensity = 0.2 A, and conductivity = 2 mS cm-1. The mechanism of PSPC-EC was characterised using techniques including scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The TC decomposition pathway was proposed based on the generation of its intermediate products. A toxicity estimation software tool (TEST) model was used to evaluate the toxicity of TC and its main degradation products, and most of its intermediates were found to be less toxic than TC. The contribution ratios of floc adsorption and electrochemical oxidation for removing TC were 74.17% and 21.48%, respectively. The highest TC removal rate reached 95% with an operating cost of 0.011 USD/m3. Finally, under the optimum conditions identified, actual livestock wastewater was treated by PSPC-EC. Compared with conventional EC and coagulation treatment techniques that consume electricity and produce pollution, the results indicate that the PSPC-EC technique with changing current operation mode is a more cost-effective and attractive option for removing TC from livestock wastewater.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Animais , Antibacterianos , Eletrocoagulação , Eletrodos , Gado , Tetraciclina/toxicidade , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/toxicidade
19.
Sci Total Environ ; 807(Pt 3): 151057, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-34710427

RESUMO

Using colloidal biliquid aphrons (CBLAs) for density control has been proved to a promising technology in dense non-aqueous phase liquids (DNAPLs) contaminated aquifer remediation. However, the transport and distribution of CBLAs in aquifer is an urgent issue for actual application in groundwater. Especially considering the fact that CBLAs have a lower density than water. In this work, the role of buoyancy force on CBLA transport in water-saturated sandbox was investigated, and the force model of CBLA in pore space was developed. Furthermore, the density regulation of trichloroethylene (TCE) in sandbox was studied using CBLA. We found that buoyancy plays a significant role compared with other interaction forces in the transport of CBLA, and the sine of the rising angle of CBLA has a significant correlation with the force on CBLA. CBLA at 5 times the volume of TCE displaced the TCE at the bottom of the tank by upward mobility and the maximum concentration dramatically decreased to 31.23 mg/L. These results can be used for predicting the transport of CBLA (as well as other remediation reagents that are less dense than water) in aquifer and are beneficial to the subsequent remediation application of CBLA in actual contaminated sites.

20.
Sci Total Environ ; 850: 157963, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-35952871

RESUMO

Electro-oxidation (EO) has received increasing attention as an efficient and green method for removing pollutants from wastewater. Chloride anions (Cl-), which commonly exist in wastewater, can act as an electrolyte for the EO process. However, the role of reactive chlorine species (RCS) generated near electrodes is often underestimated. In this study, we generated hydroxyl radicals (OH) and RCS in a boron-doped diamond (BDD) electrode system and investigated its degradation mechanism for ofloxacin (OFX) removal. The findings suggested that OFX degradation was dominated by OH existing near the anode in solution, with RCS playing a supporting role. Based on the produced intermediates, we proposed an OFX decomposition pathway. The biological toxicities of the intermediates were evaluated through the ECOSAR and T.E.S.T. procedure. Nearly half of the intermediates are less toxic than the parent compound. After optimizing the operating parameters by the response surface methodology, 20 mg/L OFX was almost completely degraded after 10 min of reaction in 1.45 g/L NaCl with a current density (j) of 18 mA/cm2, and the total organic carbon was decreased by 30.55 %. The energy consumption and current efficiency were 0.648 kW·h/gTOC and 8.65 %, respectively. Comparing the operating costs of the proposed and other EO methods, our method emerged as a viable new treatment scheme for similar polluted wastewaters. This study aims to comprehensively understand the potential application value of BDD electrodes in the treatment of Cl- containing organic wastewater.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Boro , Cloretos , Cloro , Diamante , Eletrodos , Ofloxacino , Oxirredução , Cloreto de Sódio , Poluentes Químicos da Água/análise
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