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1.
Artigo em Inglês | MEDLINE | ID: mdl-32239788

RESUMO

Hydrogenolysis of alkyls substituted cyclopentadienyl (Cp R ) ligated thorium tribenzyl complexes [(Cp R )Th( p -CH 2 -C 6 H 4 -Me) 3 ] ( 1~6 ) afforded the first examples of molecular thorium trihydrido complexes (Cp R )Th( u -H) 3 ] n (Cp R = C 5 H 2 ( t Bu) 3 or C 5 H 2 (SiMe 3 ) 3 , n = 5; C 5 Me 4 SiMe 3 , n = 6; C 5 Me 5 , n = 7; C 5 Me 4 H, n = 8) ( 7~10 and 12 ) and [(Cp # ) 12 Th 13 H 40 ] (Cp # = C 5 H 4 SiMe 3 ) ( 13 ). The nuclearity of the metal hydride clusters depends on the steric profile of the cyclopentadienyl ligands. The hydrogenolysis intermediate, tetra-nuclear octahydrido thorium dibenzylidene complex [(Cp ttt )Th( u -H) 2 ] 4 ( u - p -CH-C 6 H 4 -Me) 2 (Cp ttt  = C 5 H 2 ( t Bu) 3 ) ( 11 ) was also isolated. All the complexes were characterized by NMR spectroscopy and single-crystal X-ray analysis. Hydride positions in [(Cp Me4 )Th( u -H) 3 ] 8 (Cp Me4 = C 5 Me 4 H) were further precisely confirmed by single-crystal neutron diffraction. DFT calculations strengthen the experimental assignment of the hydride positions in the complexes 7 to 12 .

2.
Chemosphere ; 251: 126286, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32146182

RESUMO

Single-walled carbon nanotubes (SWNTs) can be used as 1D electrochemical disinfection material for point-of-use water treatment but are limited by their poor durability and possible cytotoxicity. Immobilizing SWNTs in nanofibers with electrospinning served as slow-release technology develop a novel with a lasting antibacterial and (eco-) toxicological alleviation of SWNTs. Hence, the single-walled carbon nanotubes-polyacrylonitrile/polyurethane/polyaniline (SWNTs-PAN/TPU/PANI, SPTP) composite electrospun nanofiber membrane was successfully fabricated by co-electrospinning process and the electrochemical filtration and disinfection system of point-of-use drinking water treatment is constructed. In the absence of electrolysis, the SPTP filter is effective for complete removal of bacteria by sieving mechanism. Concomitant electrolysis in the course of filtration results in significantly increased inactivation of sieved bacteria. Application of 3.0 V leads to complete (5 log) inactivation of bacteria within 20 min. 5-cycle experiments, membrane flux and shake flask tests prove that composite restrict the excessive release of SWNTs retaining the long-lasting antibacterial properties of SPTP membrane. At 1.0 and 2.0 V, electrolyte concentration and composition is irrelevant to electrochemical inactivation consistent with oxidation of SPTP filter. Bacterial reactive oxygen species (ROSs) also support an oxidation mechanism. At 3.0 V, electrochemical disinfection mainly relies on indirect oxidation.

3.
Int J Neurosci ; : 1-7, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32098537

RESUMO

Pituitary metastasis(PM) from renal cell carcinoma(RCC) is rare, and is easy to be misdiagnosed. Here, we present a case of pituitary metastasis from clear-cell renal cell carcinoma(ccRCC) which was difficult to distinguish from other sellar region tumors. In addition, we systematically review the literature to find the characteristics of different tumors of the sellar region. It provides a new idea for the diagnosis of sellar region tumors in the clinic.

4.
Bioresour Technol ; 300: 122703, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31911312

RESUMO

A microbial fuel cell (MFC) was constructed with a Ru/Fe-modified-anode prepared by reduction and coating for enhancing diclofenac (DCF) degradation. Results showed that Ru0 and Fe0 were dispersed uniformly on Ru/Fe-modified-electrode surface, and Ru/Fe existed as an alloy structure. Due to catalysis of Ru/Fe, both electrochemical activity and DCF-degradation performance of Ru/Fe-modified-anode-MFC (Ru/Fe-MFC) were enhanced compared to carbon-felt-anode-MFC (CF-MFC). The maximum power density of Ru/Fe-MFC reached 0.600 W m-2, and DCF-degradation in Ru/Fe-MFC followed the pseudo-first-order-kinetic model with kobs of 0.711 d-1 which was 1.08, 1.34 and 2.21 times higher than that of Ru-modified-anode-MFC (Ru-MFC), Fe-modified-andoe-MFC (Fe-MFC) and CF-MFC, respectively. Results also showed that DCF-degradation and power generation would compete for electrons in Ru/Fe-MFC. Ru/Fe-modified-anode accelerated the enrichment of electro-active bacteria and DCF-degrading bacteria such as Geobacter, Clostridium, Sedimentibacter, Pseudomonas and Desulfovibrionaceae. Stepwise dechlornation occurred for DCF-degradation mainly due to synergistic reaction of Ru/Fe and DCF-degrading bacteria within Ru/Fe-MFC.


Assuntos
Fontes de Energia Bioelétrica , Geobacter , Diclofenaco , Eletrodos , Cinética
5.
Sci Total Environ ; 703: 135586, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767336

RESUMO

The pharmaceutical industry produces large volumes of low C/N ratio wastewater that is difficult to treat. In this study, we isolated Achromobacter sp. JL9 with high efficiency for sulfamethoxazole degradation and nitrogen conversion in low C/N ratio pharmaceutical wastewater. The SMX biodegradation and nitrogen removal ratio were 92.4% (nitrate-N), 86.7% (ammonia-N), 89.4% (total nitrogen), and 90.4% (SMX). The reaction kinetics and reaction rate constant were C/N ratio-, SMX concentration-, and dissolved oxygen concentration-dependent, and the highest reaction rate constant for SMX biodegradation was 0.0384 min-1. Gaseous compounds analysis and Nap gene amplification analysis by gas chromatography (GC) and polymerase chain reaction (PCR), respectively, showed N2 as an end product during nitrogen conversion. Moreover, toxicity assays were conducted by the inhibition percentage (PI) and agar well diffusion methods. The toxicity of the medium gradually decreased, falling within the nontoxic range after 96 h. The present study showed that biological technologies could be an effective, economical, and environmentally friendly remediation against pharmaceutical pollutants.


Assuntos
Achromobacter/metabolismo , Biodegradação Ambiental , Nitrogênio/metabolismo , Sulfametoxazol/metabolismo , Poluentes Químicos da Água/metabolismo , Águas Residuárias/química , Águas Residuárias/microbiologia
6.
ISA Trans ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31818485

RESUMO

In this work, we propose a disturbance rejection methodology to deal with control problem of unstable non-minimum phase (NMP) systems. Firstly, we propose a two degrees-of-freedom control structure, which consists of an outer loop feedback controller and an inner loop disturbance observer (DOB). Specifically, the controller is designed for desired control performance, whereas the robust DOB is applied to deal with external disturbances and internal uncertainties. By analyzing the robust internal stability, several design requirements on both controller and DOB are presented for the control system. The H2 theory is adopted for controller design. Then, we propose a systematic DOB optimization method for unstable NMP systems. The proposed method synthesizes the relative order, robust internal stability and mixed sensitivity optimization together to formulate the cost function. The standard H∞ method is introduced to acquire the optimal solution that guarantying the design requirements. Simulations show that the proposed method can deal with the control system design for the unstable NMP systems, and it also has better performance comparing with the traditional method.

7.
Huan Jing Ke Xue ; 40(7): 3257-3262, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854726

RESUMO

Given the potential risk posed by antibiotic resistance genes (ARGs) to the eco-environment in the hilly purple soil region, which has been intensively utilized by human, surface soil samples were collected from feedlots of pig, chicken, and cattle farms and were analyzed for the diversity and abundance of ARGs using high-throughput QPCR. In total, 79 ARGs and 5 mobile genetic elements (MGEs) were detected across all samples. Among these genes, multidrug resistance genes were the most abundant type of ARGs. More abundant and diverse ARGs were observed in feedlot soil samples from pig and chicken farms than those from cattle feedlot soils, and these samples showed different distribution patterns of ARGs. High abundance of MGEs and their significant correlation with ARGs (P<0.05) implied an important role of MGEs in the dissemination of ARGs in livestock feedlot soils.


Assuntos
Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Sequências Repetitivas Dispersas , Gado , Microbiologia do Solo , Animais , Bovinos , Galinhas , Fazendas , Esterco , Suínos
8.
Dalton Trans ; 48(48): 17919-17924, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31782451

RESUMO

A heteroleptic barium aminobenzyl complex [(TpAd,iPr)Ba(o-CH2C6H4-NMe2)] (1) was obtained in excellent yield from a simple one-pot reaction. Treatment of [(TpAd,iPr)Ba(o-CH2C6H4-NMe2)] (1) with two equivalents of AlR3 (R = Me, Et) led to the formation of barium tetraalkylaluminate complexes [(TpAd,iPr)Ba(AlR4)]n (R = Me, n = 2, 2; R = Et, n = 1, 3) as dimers or monomers in the solid state. The TpAd,iPr ligand-free peralkylated barium complex [Ba(AlEt4)2]n was isolated by the addition of ten equivalents of AlEt3 under the same conditions. The donor-induced aluminate cleavage is not applicable when donor solvents are added to complexes 2 and 3. In the solution of complexes 2 and 3, the alkylaluminate moieties and TpAd,iPr ligands show a rapid fluxional behavior in [D8]toluene solution over the temperature range of -70 to 25 °C, without any significant decoalescence of the corresponding proton signals.

9.
Oncol Lett ; 18(5): 4651-4658, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31611974

RESUMO

The aim of the present study was to investigate the role and potential regulatory mechanisms of cyclin B1 (CCNB1) in the proliferation, apoptosis and epithelial-to-mesenchymal transition (EMT) in pituitary adenomas. A total of 24 specimens were included in the present study. The expression levels of CCNB1 protein in two normal pituitary and 22 pituitary adenoma tissues were determined by western blotting. CCNB1 was knocked-down by lentiviral-mediated infection of short hairpin RNA (shRNA) in GH3 and MMQ cell lines. The proliferation, cell cycle and apoptosis of GH3 and MMQ cell lines were detected using a Cell Counting Kit-8 and flow cytometer. Reverse transcription-quantitative PCR was utilized to detect the expression level of CCNB1 gene and EMT markers. In the present study, resveratrol (RES) was used as an inhibitor of CCNB1. The protein expression level of CCNB1 in pituitary adenomas was higher than that in normal pituitary tissue, as assessed by western blot analysis. In addition, the expression level of CCNB1 in invasive pituitary adenomas was higher when comparing invasive pituitary adenomas and non-invasive pituitary adenomas. Knockdown of CCNB1 resulted in significant decreases in cell viability and proliferation, arrested cell cycle at the G2/M phase and increased apoptosis. In addition, knockdown of CCNB1 significantly decreased the expression levels of the mesothelial cell marker N-cadherin (P<0.001), but significantly increased the expression levels of the epithelial cell markers E-cadherin (P<0.01) and p120-catenin (P<0.001). Further analyses identified that RES inhibited the expression level of CCNB1, and RES treatment exhibited a similar effect as CCNB1 shRNA infection. The present study suggested that suppressing the expression level of CCNB1 could regulate the proliferation and apoptosis of pituitary tumor cells and alter the expression level of various EMT markers. In addition, RES treatment could be used as an inhibitor of CCNB1. The present study also identified the molecular mechanisms underlying CCNB1 role in EMT.

10.
J Transl Med ; 17(1): 336, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31585531

RESUMO

BACKGROUND: To investigate the relationship between cyclin B1 (CCNB1) gene expression and cavernous sinus invasion in pituitary adenomas. METHODS: Twenty-four pituitary adenoma tissue samples were examined by RT-qPCR and Western blot to assess the mRNA expression levels and protein levels of CCNB1, E-cadherin and N-cadherin. Correlation analyses between the expression levels of E-cadherin, N-cadherin and CCNB1 were performed. After lentivirus-mediated knockdown of CCNB1 in rat pituitary adenoma cell lines (GH3 and GT1-1), cell function changes were studied. The relationship between CCNB1 and epithelial-mesenchymal transition (EMT) was further verified by animal experiments. RESULTS: CCNB1 and N-cadherin gene expression were significantly higher in the invasive pituitary adenomas than in the non-invasive pituitary adenomas. Conversely, E-cadherin expression in the invasive pituitary adenomas was significantly lower. CCNB1 gene expression was downregulated in the GH3 and GT1-1 pituitary adenoma cell lines; N-cadherin expression was also decreased, but E-cadherin expression was increased. These results were confirmed in vivo. After downregulation of CCNB1, cell invasion and migration was significantly reduced in Transwell experiments. CONCLUSION: High CCNB1 expression in pituitary adenoma affects cavernous sinus invasion through EMT.

11.
Ecotoxicol Environ Saf ; 185: 109676, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31539769

RESUMO

Although it has been proved that abiotic processes can transform tetracycline (TEC), little is known about how microbial processes may degrade TEC in aquatic environment. The objective of this study is to investigate the biodegradation pathway of TEC by strain Klebsiella sp. SQY5 and molecular mechanism of TEC resistance under the aerobic conditions. Effects of mycelium, intracellular, and extracellular enzyme on TEC degradation process were explored, suggesting that mycelium contributed the most of TEC degradation with a maximum efficiency of 58.64%. Biodegradation characteristic of TEC and its degradation products were studied. The results showed that nine possible biodegradation products were identified, and a potential biodegradation pathway was proposed including the removal of methyl, carbonyl, and amine groups. The functional genes of this bacterium were also determined by genomics, and analysis indicated that functional genes that could be relevant to hydrolysis, ring opening and oxidation played an important role in the process of TEC biodegradation. Results from this study can provide a theoretical basis for better estimating the fate, transportation, and degradation of antibiotics in aquatic environment.


Assuntos
Antibacterianos/análise , Genes Bacterianos , Klebsiella/metabolismo , Tetraciclina/análise , Poluentes Químicos da Água/análise , Aerobiose , Biodegradação Ambiental , Genômica , Klebsiella/enzimologia , Klebsiella/genética , Oxirredução
12.
Environ Pollut ; 255(Pt 2): 113226, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546075

RESUMO

In this paper, Fe3O4@MIL-68 (Al), a magnetic aluminum-based metal organic framework, was synthesized by a simple method and used as a novel and effective adsorbent for the removal of minocycline (MC) from aqueous solutions. The material was thoroughly characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and N2 adsorption isotherms. The characterization results showed that the original structure of MIL-68(Al) was unchanged by the addition of Fe3O4 nanoparticles, and that the obtained material had a strong magnetic response which also promoted its adsorption. Batch adsorption experiments were conducted by the varying the adsorption time, temperature, initial MC concentration and pH. The maximum adsorption amount of MC onto Fe3O4@MIL-68 (Al) was 248.05 mg g-1 (t = 160 min, pH = 6, Co = 60 mg L-1), and the adsorption kinetics followed a pseudo-second-order model, and the adsorption isotherms conformed to the Freundlich equation. The adsorption mechanism of the magnetic metal organic framework materials were determined to involve complex interactions, including Al-N and Fe-N covalent bonds, hydrogen bonding, electrostatic adsorption, and π-π stacking. Combined the results indicate that Fe3O4@MIL-68 (Al) is an outstanding adsorbent for the removal of MC from water.


Assuntos
Minociclina/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Alumínio/química , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Magnetismo , Estruturas Metalorgânicas , Microscopia Eletrônica de Varredura , Água/química , Poluentes Químicos da Água/química , Difração de Raios X
13.
Sensors (Basel) ; 19(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31510003

RESUMO

Navigation is a precondition for ocean space vehicles to work safely in polar regions. The traditional polar algorithms employ the grid strapdown inertial navigation system (SINS) as the backbone and Doppler velocity log (DVL) output velocity as measurements to constitute the integrated navigation system, of which, however, the position errors still accumulate with time. The ultra-short baseline (USBL) position system can provide position information that can be used to improve the performance of the SINS/DVL integrated system. Therefore, a grid SINS/DVL/USBL integrated algorithm for polar navigation is proposed in this paper. In order to extend the availability of the USBL and improve integration accuracy in polar regions, the USBL observation model is established based on the relative position measurement firstly. Then, a grid SINS/DVL/USBL integrated algorithm is proposed to fuse the information of these sensors with a modified Kalman filter (MKF) dealing with the sparse USBL output. Finally, a vector fault detection method, which takes the measurements as detection objects instead of the filter, is designed to locate the measurement fault and can be employed by the centralized filter to improve the fault-tolerant. Simulation and experiment results show that the proposed grid SINS/DVL/USBL integrated navigation system can further restrain SINS errors especially the position errors effectively. Meanwhile, the vector fault detection method can detect and isolate the fault measurements of centralized filter immediately and accurately. Therefore, the proposed fault-tolerant grid SINS/DVL/USBL integrated navigation algorithm can improve the reliability and accuracy of polar navigation for ocean space application.

14.
Chemosphere ; 237: 124493, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31398611

RESUMO

Aluminum-based metal-organic framework/sodium alginate-chitosan (Al-MOF/SA-CS) composite beads were synthesized and employed as an adsorbent for the removal of bisphenol A (BPA). Several methods, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), nitrogen adsorption-desorption isotherms and X-ray photoelectron spectroscopy (XPS), were used to characterize the prepared adsorbents. Results demonstrated that the introduction of CS could change the porosity of the beads and the obtained Al-MOF/SA-CS composite beads possessed higher surface area and total pore volume comparing with the beads without CS. Batch experiments were carried out to explore the adsorption performance and the results displayed that the enhanced adsorption capacity was achieved by Al-MOF/SA-CS beads compared to the Al-MOF/SA ones. It is also found from the fitting results that the adsorption process fitted well with the pseudo-second-order kinetics model and followed the Freundlich isotherm model. Importantly, the composite beads could be easily recycled and regenerated by methanol and the adsorption efficiency still maintained as high as 96% even after five cycles. Furthermore, it can be inferred from the experimental results that the π-π stacking, hydrogen bonding and cation-π interaction could be the primary adsorption mechanisms. Considering the high adsorption properties, good water stability, especially easy separation, and excellent recyclability, Al-MOF/SA-CS composite beads could be a promising adsorbent for the removal of BPA from contaminated water.


Assuntos
Alumínio/química , Compostos Benzidrílicos/análise , Fenóis/análise , Poluentes Químicos da Água/análise , Adsorção , Alginatos/química , Quitosana/química , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Difração de Raios X
15.
Dalton Trans ; 48(31): 11706-11714, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31274141

RESUMO

A series of mono-anionic non-carbocyclic ligands, including bidentate benzamidinate [PhC(NDipp)2] (Dipp = C6H3-2,6-iPr2), iminophosphinamide [Ph2P(NDipp)2] and phosphinoamide [Ph2PNDipp], and tridentate hydrotris(3,5-dimethyl-1-pyrazolyl)borate (TpMe2) were used to stabilize the corresponding thorium(iv) trialkyl complexes [PhC(NDipp)2]Th(CH2SiMe3)3 (1), [Ph2P(NDipp)2]Th(CH2SiMe3)3 (2), [Ph2P(NDipp)]Th(p-CH2-C6H4-Me)3 (3) and (TpMe2)Th(CH2SiMe3)3 (4), which were characterized by NMR spectroscopy and single-crystal X-ray analysis. Complexes 1-4 in combination with [Ph3C][B(C6F5)4] and AliBu3 form non-Cp-ligated actinide catalyst systems to show high activity and high cis-1,4-selectivity (89.9%) or trans-1,4-selectivity (91.4%) for the polymerization of isoprene. The reaction rate and selectivity of complexes 1 and 2 were controlled by the crowded space around the thorium centre, corroborated by the kinetics of the polymerization and the steric maps.

16.
Chem Commun (Camb) ; 55(59): 8560-8563, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31271170

RESUMO

The monomeric actinide dihydrido complex [(CpAr*)(Cp*)ThH2(THF)] (2) bearing the super-bulky penta-arylcyclopentadienyl (CpAr* = C5Ar*5, Ar* = 3,5-tBu2-C6H3) and pentamethylcyclopentadienyl (Cp* = C5Me5) ligands was obtained for the first time. Complex 2 underwent unique Th-H addition reactions with various unsaturated compounds to afford the corresponding five-membered metallacycles, including the first example of actinide metallacyclopentyne [(CpAr*)(Cp*)Th(PhCH-C[triple bond, length as m-dash]C-CHPh)] (4).

17.
Dalton Trans ; 48(32): 12315-12325, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31342025

RESUMO

In this paper we report a series of Al(iii) complexes supported by N,O-bidentate ß-pyrazyl functionalized enolate ligands HL1-HL5 (L = (6-Me-2,5-C4H2N2)-CH[double bond, length as m-dash]C(R)-O-), (R = tBu, Ph, p-tolyl, p-OMePh, o-tolyl) and their exploitation for the ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA). The structures of the form LAlMe2 (1a-5a) or L2AlMe (1b-4b) were isolated depending on the ligand or stoichiometry of complexation. The investigation of these complexes toward the ROP of both ε-CL and rac-LA under the same conditions showed that dimethyl-aluminum complexes LAlMe2 (1a-5a) gave a higher activity than monomethyl-aluminum complexes L2AlMe (1b-4b). Meanwhile, monomethyl-aluminum complexes 1b-4b promoted the ring-opening polymerization with a better control over molecular weights and polydispersities than 1a-5a. Moreover, all of the LAlMe2 and L2AlMe produced PLA with strong isotactic bias (Pm up to 0.77) and narrow distributions. Generally, a ß-pyrazyl enolate system exhibited significantly higher catalytic activity for the ROP of ε-CL and rac-LA than the analogous ß-quinolyl enolate systems reported recently. The results are discussed in terms of electronic and steric properties affected by the substituents on the ligands.

18.
Bioresour Technol ; 288: 121567, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31170687

RESUMO

The present study aimed to investigate Klebsiella sp. SQY5-mediated tetracycline (TEC) degradation, nitrogen (N) conversion, and mechanisms underlying this process as influenced by various carbon and N sources under aerobic conditions. Effects of additional organic carbon sources on TEC degradation and N conversion processes were explored, and we found that 34.71% of TEC was degraded at removal rates of 0.97 mg·L-1·h-1 for NH4+-N and 1.97 mg·L-1·h-1 for NO3--N. A study examining powder natural algal powder in aquaculture wastewater as a carbon source for TEC degradation and denitrification process was also discussed. It suggested that 49.95% of TEC and 60.45% of NO3--N were removed with a reduction and denitrification rate of 0.11 mg·L-1·h-1 and 1.34 mg·L-1·h-1, respectively, within 72-108 h. Mechanisms underlying TEC degradation and N conversion processes were also proposed, and analysis indicated that specific functional genes played an important role in this process.


Assuntos
Carbono , Nitrogênio , Biodegradação Ambiental , Desnitrificação , Tetraciclina
19.
Dalton Trans ; 48(24): 8565-8568, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31157345

RESUMO

Treatment of the barium hydride complex [(TpAd,iPr)Ba(µ-H)]2 (TpAd,iPr = hydrotris(3-adamantyl-5-isopropyl-pyrazolyl)borate) (1) with an excess amount of 1,1-diphenylethylene (DPE) afforded the corresponding mono-DPE adduct [(TpAd,iPr)Ba(η6-Ph)C(Ph)Me] (2) and di-DPE adduct [(TpAd,iPr)Ba(η6-Ph)C(Ph)-CH2-C(Ph)2Me] (3), which could convert to each other through a reversible equilibrium reaction. Complex 1 catalysed DPE hydrogenation under mild conditions (30 °C, 6 atm, 5 mol% cat.).

20.
Water Res ; 156: 252-263, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30921541

RESUMO

Field-scale studies of natural colloid mobilization and transport in finely fractured aquifer as well as the source identification of groundwater colloids are of great importance to the safety of shallow groundwater. In this study, the daily monitoring of fracture flow from a sloping farmland plot and the biweekly monitoring of three lowland shallow wells within the same catchment were carried out simultaneously in 2013. The effects of physicochemical perturbations on groundwater colloid dynamics were explored in detail using partial redundancy analysis, structural equation modeling, Pearson correlation and multi-linear regression analyses. The characterization and source identification of groundwater colloids were addressed via multiple parameters. The daily colloid concentration in the fracture flow varied between 0.54 and 31.90 mg/L (1.64 mg/L on average). Unique periods of high colloid concentration (5.59 mg/L on average) occurred during the initially generated flow following the dry season. In comparison, a narrower colloid concentration range of 0.24-11.66 mg/L was observed in the lowland shallow wells, with a smaller temporal variation than that of the fracture flow. A low percentage (2.4-7.0%) of colloids and a high percentage (47.7-92.0%) of coarse particles (2-10 µm) were present in the lowland well water. Hydraulic perturbation by rainwater infiltration in the sloping farmland was the dominant mechanism for colloid mobilization in general; this effect retreated to secondary importance behind chemical perturbations (pH, Mg2+ and DOC) at low flow discharges (<1.3 L/min). In contrast, water chemistry (e.g., EC, cations and DOC concentrations) exhibited a major effect on colloid dynamics in the water of the lowland wells, except for the extremely high-salinity water of one well, in which water temperature showed a negative dominant influence on colloid stability. The combined use of multiple parameters (e.g., mineral composition and organic matter, calcium carbonate and δ13C contents) traced groundwater colloids to the shallow soil in the upper farmlands. It is strongly advised that in finely fractured aquifers within agricultural catchments, not only the small colloids but also the coarse particles in the size range of 2-10 µm should be monitored in case of colloid-associated contamination from agricultural wastes e.g., N, P, pesticides and/or heavy metals, especially at the early stages of the rainy seasons.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Coloides , Monitoramento Ambiental , Fazendas , Movimentos da Água , Poços de Água
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