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1.
Nanoscale ; 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404574

RESUMO

Metal-organic frameworks (MOFs) have emerged as attractive materials for energy and environmental-related applications owing to their structural, chemical and functional diversity over the last two decades. It is known that the poor carrier mobility and low electrical conductivity of ordinary MOFs severely limit their utility in practical applications. In the past 10 years, several MOF materials with high carrier mobility and outstanding electrical conductivity have received a worldwide upsurge of research interest and many techniques and strategies have been used to synthesize such MOFs. In this critical review, we provide an overview of the significant advances in the development of conductive MOFs reported until now. Their theoretical and synthetic design strategies, conductive mechanisms, electrical transport measurements, and applications are systematically summarized and discussed. In addition, we will also give some discussions on challenges and perspectives in this exciting field.

2.
Adv Mater ; : e2007549, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33506541

RESUMO

The shuttle effect of lithium polysulfides (LiPS) and potential safety hazard caused by the burning of flammable organic electrolytes, sulfur cathode, and lithium anode seriously limit the practical application of lithium-sulfur (Li-S) batteries. Here, a flame-retardant polyphosphazene (PPZ) covalently modified holey graphene/carbonized cellulose paper is reported as a multifunctional interlayer in Li-S batteries. During the discharge/charge process, once the LiPS are generated, the as-obtained flame-retardant interlayer traps them immediately through the nucleophilic substitution reaction between PPZ and LiPS, effectively inhibiting the shuttling effect of LiPS to enhance the cycle stability of Li-S batteries. Meanwhile, this strong chemical interaction increases the diffusion coefficient for lithium ions, accelerating the lithiation reaction with complete inversion. Moreover, the as-obtained interlayer can be used as a fresh 3D current collector to establish a flame-retardant "vice-electrode," which can trap dissolved sulfur and absorb a large amount of electrolyte, prominently bringing down the flammability of the sulfur cathode and electrolyte to improve the safety of Li-S batteries. This work provides a viable strategy for using PPZ-based materials as strong chemical scavengers for LiPS and a flame-retardant interlayer toward next-generation Li-S batteries with enhanced safety and electrochemical performance.

3.
Chemosphere ; : 128818, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33223206

RESUMO

Exploration of novel advanced oxidation systems with high efficiency toward radical generation is of significant importance due to the extensive and versatile application of reactive species in the wastewater treatment. Herein we report a simple UV-catalytic homogeneous advanced oxidation system (UV/Fe3+/hydrogen sulfite (BS)), which is capable of generating abundant radicals (e.g., SO3-, SO4-, SO5- and HO) in the aqueous environment. Sulfamethoxazole (SMX) degradation using this system was tested. Results indicated that SMX could be degraded effectively by UV/Fe3+/BS and sulfate radical (SO4-) and hydroxyl radical (HO•) were verified to be presented in this system and be contributive to SMX removal. The acidic pH (4.0) and a low BS/Fe3+ ratio (10:1) were suitable for SMX degradation. The presence of fulvic acid (FA) and HCO3- strongly inhibited the degradation of SMX, but obvious acceleration was observed in the presence of NO3- due to its contribution on additional radical generation by photosensitization. Based on the detected transformation products through LC-MS analysis, the degradation pathway of SMX by UV/Fe3+/BS was proposed including hydroxylation and bond cleavage.

4.
ACS Appl Mater Interfaces ; 12(36): 40433-40442, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32812729

RESUMO

Carbon nitride has drawn widespread attention as a low-cost alternative to metal-based materials in the field of photocatalysis. However, the traditionally synthesized carbon nitrides always suffer a bulky architecture, which limits their intrinsic activities. Here, a cycloaddition reaction is proposed to synthesize a triazine-based precursor with implanted sodium and cyano groups, which are mostly retained in the resulting carbon nitride after the following polymerization. Incorporated sodium and cyano defects can not only tune the band structure of the carbon nitride but also provide more additive active sites. The optimized properties enable it an adorable photocatalytic hydrogen evolution rate of 1070 µmol h-1 g-1, varying by almost an order of magnitude from the pristine carbon nitride (79 µmol h-1 g-1). Moreover, a sequential self-assembly strategy has been adopted to further improve its architecture. As a consequence, a three-dimensional (3D) porous carbon nitride microtube cluster is constructed, indicating abundant exposed active sites and the faster separation of charge carriers. The corresponding photocatalytic hydrogen evolution rate is 1681 µmol h-1 g-1, which is very competitive compared with the reported pure carbon nitride photocatalysts. Briefly, this new approach may offer opportunities to fabricate task-specific carbon- and nitrogen-based materials from the molecular level.

5.
Environ Technol ; : 1-9, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32295490

RESUMO

In this study, peracetic acid (PAA) activated by Fe(II) was proposed to remove diclofenac (DCF) in polluted water. It was found that Fe(II)/PAA system could effectively remove DCF at neutral condition, which has a significant advantage over classical Fenton process. According to the result of scavenging experiment, both hydroxyl radical and peroxy radical were considered to be responsible for the degradation of DCF. The influence of several operational parameters including initial pH, Fe(II) dosage, PAA concentration and common water matrix on DCF removal were investigated. 80% DCF was removed at mild condition (pH 6-7) within 60 s, and its removal rate could be enhanced with the increase in Fe(II) dosage and PAA concentration. Presence of [Formula: see text] and natural organic matter (NOM) was proved to have a significantly negative impact on DCF degradation. Four probable degradation pathways of DCF were proposed based on the detected reaction products, including hydroxylation, C-N bond cleavage, decarboxylation and dehydrogenation.

6.
Small ; 16(8): e1907043, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32003933

RESUMO

Conjugated coordination polymers (CPs) with designable and predictable structures have drawn tremendous attention in recent years. However, the poor electrical conductivity and low structural stability seriously restrict their practical applications in electronic devices. Herein, the rational design and synthesis of a hierarchically structured 2D bimetallic CoNi-hexaaminobenzene CPs derived from Co(OH)2 are reported as an efficient oxygen evolution reaction (OER) self-supported electrode. The as-obtained electrode possesses high electrochemical surface area and intrinsic activity, exhibiting high electrochemical catalytic activity, favorable reaction kinetics performance, and strong durability compared with those of the powder catalysts. As a result, the electrode delivers low overpotential of 219 mV @ 10 mA cm-2 and Tafel slope of 42 mV dec-1 as well as 91.3% retention of current density after 24 h of reaction time. The results of density functional theory computations reveal that the synergistic effect of Co and Ni plays an important role in OER. This work not only presents a strategy to fabricate advanced self-supported electrodes with abundant and dense active sites, but also promotes the development of conjugated CPs for electrocatalysis.

7.
Nat Commun ; 11(1): 845, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051407

RESUMO

Encapsulation strategies are widely used for alleviating dissolution and diffusion of polysulfides, but they experience nonrecoverable structural failure arising from the repetitive severe volume change during lithium-sulfur battery cycling. Here we report a methodology to construct an electrochemically recoverable protective layer of polysulfides using an electrolyte additive. The additive nitrogen-doped carbon dots maintain their "dissolved" status in the electrolyte at the full charge state, and some of them function as active sites for lithium sulfide growth at the full discharge state. When polysulfides are present amid the transition between sulfur and lithium sulfide, nitrogen-doped carbon dots become highly reactive with polysulfides to form a solid and recoverable polysulfide-encapsulating layer. This design skilfully avoids structural failure and efficiently suppresses polysulfide shuttling. The sulfur cathode delivers a high reversible capacity of 891 mAh g-1 at 0.5 C with 99.5% coulombic efficiency and cycling stability up to 1000 cycles at 2 C.

8.
Nanoscale ; 12(3): 1833-1841, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31899470

RESUMO

Hollow porous prismatic graphitic carbon nitride with nitrogen vacancies and oxygen doping was successfully constructed using dicyandiamidine as the only raw material via a facile two-step strategy of a low-temperature hydrothermal method followed by a subsequent calcination process. The as-obtained graphitic carbon nitride showed a hollow prismatic morphology with loose spongy-like walls, a hierarchical pore structure, and a specific surface area of 220.16 m2 g-1. Such graphitic carbon nitride exhibited an ultrahigh nitrogen fixation rate of 118.8 mg L-1 h-1 gcat-1 under visible light irradiation and showed excellent stability during the reactions. A possible mechanism for photocatalytic nitrogen fixation on the catalyst was proposed as follows: under visible-light irradiation, graphitic carbon nitride with nitrogen vacancies and oxygen doping underwent charge separation to generate electron-hole pairs, and then the photogenerated electrons on the conduction band were quickly transferred to the nitrogen vacancy induced mid-gap state; consequently, the trapped electrons reacted with the activated nitrogen on the nitrogen vacancies to produce ammonia. The significant enhancement in the photocatalytic nitrogen fixation performance of graphitic carbon nitride can be attributed to its unique hollow prismatic morphology with a loose porous structure, fully exposed active sites of nitrogen vacancies, more negative conduction band, suitable visible-light response and the efficient separation of photogenerated electron-hole pairs.

9.
Small ; 15(50): e1905166, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31725197

RESUMO

Scalable and sustainable solar hydrogen production via photocatalytic water splitting requires extremely active and stable light-harvesting semiconductors to fulfill the stringent requirements of suitable energy band position and rapid interfacial charge transfer process. Motivated by this point, increasing attention has been given to the development of photocatalysts comprising intimately interfaced photoabsorbers and cocatalysts. Herein, a simple one-step approach is reported to fabricate a high-efficiency photocatalytic system, in which single-site dispersed iron atoms are rationally integrated on the intrinsic structure of the porous crimped graphitic carbon nitride (g-C3 N4 ) polymer. A detailed analysis of the formation process shows that a stable complex is generated by spontaneously coordinating dicyandiamidine nitrate with iron ions in isopropanol, thus leading to a relatively complicated polycondensation reaction upon thermal treatment. The correlation of experimental and computational results confirms that optimized electronic structures of Fe@g-C3 N4 with an appropriate d-band position and negatively shifting Fermi level can be achieved, which effectively gains the reducibility of electrons and creates more active sites for the photocatalytic reactions. As a result, the Fe@g-C3 N4 exhibits a highlighted intramolecular synergistic effect, performing greatly enhanced solar-photon-driven activities, including excellent photocatalytic hydrogen evolution rate (3390 µmol h-1 g-1 , λ > 420 nm) and a reliable apparent quantum efficiency value of 6.89% at 420 nm.

10.
Environ Technol ; : 1-15, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31560256

RESUMO

Micellar enhanced ultrafiltration (MEUF) of o-toluidine and tricyclazole in aqueous stream using polyethersulfone (PES) hollow-fibre membrane of 6 kDa molecule weight cut-off (MWCO) and sodium dodecyl sulfate (SDS) as anionic surfactant was studied. It was found that the concentration ratio and adsorption ratio were better for the determination of the optimal pollutant or surfactant concentration than the rejection rate. The excessive dosage of surfactant had only limited effect on the separation and concentration of o-toluidine and tricyclazole but could further decrease the permeate flux. The transmembrane pressure had a significantly positive effect on the permeate flux and recovery ratio. o-Toluidine was significantly separated and concentrated by lowering the solution pH, while tricyclazole reached the best treatment efficiency in near-neutral pH condition. The sodium salts (i.e. Na2SO4, NaCl and Na2CO3) could lead to the increase in the adsorption ratio of SDS. However, Na2CO3 could result in the decrease in both the rejection rates and adsorption ratios of o-toluidine and tricyclazole. The distribution coefficient, micellar loading and micelle binding constant were evaluated to confirm the effectiveness for the MEUF treatment of these two pollutants.

11.
Chemosphere ; 237: 124518, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549645

RESUMO

As an emerging pollutant, Diclofenac (DCF) has potential threats to ecosystem and human health, and it can hardly be removed by conventional wastewater treatment processes. In this study, Fe(II)-activated bisulfite (BS), an advanced oxidation process, was used for rapid removal of DCF. The effect of initial pH, Fe(II) dosage, BS concentration, dissolved oxygen and reaction temperature on DCF removal and its degradation mechanism were investigated. Compared to Fe(II)/persulfate system, the removal efficiency of DCF was higher by Fe(II)/BS, and its degradation followed pseudo-first order kinetic model. Due to the morphology of Fe(II) and BS, the optimal pH for DCF degradation was 4.0. The increased initial Fe(II) or BS concentration promoted DCF degradation while excess Fe(II) or BS caused an inhibition effect as a SO4- scavenger. Dissolved oxygen was an essential factor inducing the conversion of SO3- to SO4-, while it had no effect on DCF removal in the range of 4.6-8.3 mg L-1. The activation energy of this reaction was calculated to be 120.75 ±â€¯3.43 kJ mol-1 based on the improved DCF degradation with increasing temperature. According to the radical scavenging experiments, the contribution of SO4-, HO and the other reactive species to DCF degradation in Fe(II)/BS system were 71.1%, 24.6% and 4.3%, respectively. Nine transformation products were detected using UPLC-Q-TOF-MS. The potential degradation mechanism of DCF was thus proposed showing five reaction pathways including hydroxylation, decarboxylation, dehydration, dechlorination and formylation.


Assuntos
Diclofenaco/química , Sulfitos/química , Poluentes Químicos da Água/química , Ecossistema , Compostos Ferrosos , Humanos , Cinética , Oxirredução , Poluentes Químicos da Água/análise
12.
Nanoscale ; 11(27): 12997-13006, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31265035

RESUMO

Ammonia is an important raw material in the fertilizer industry and a promising H-based fuel. However, its synthesis still largely relies on the conventional Haber-Bosch process, which is not only energy-consuming, but also environmentally damaging. Alternatively, the electrochemical synthesis of ammonia has drawn considerable interest. Herein, sandwich-like reduced graphene oxide/yolk-shell-structured Fe@Fe3O4/carbonized paper has been synthesized and employed as a freestanding electrode for nitrogen reduction reaction at room temperature and atmospheric pressure. The electrocatalytic measurements show that the as-obtained freestanding electrode exhibits high electrocatalytic activity (NH3 formation rate of 1.3 × 10-10 mol cm-2 s-1), excellent selectivity (faradaic efficiency of 6.25%), and good stability, which are equivalent to (or even higher than) those of previously reported noble metal-based catalysts under comparable reaction conditions. The superior electrocatalytic performance of the rGO/Fe@Fe3O4/CP freestanding cathode for electrochemical synthesis of ammonia is mainly attributed to its unique sandwich-like nanoarchitecture with the middle yolk-shell-structured Fe@Fe3O4 nanoparticles and the synergistic effect between rGO and Fe@Fe3O4.

13.
ChemSusChem ; 12(12): 2780-2787, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-30938925

RESUMO

Low-cost and high-efficiency electrocatalysts for the hydrogen evolution reaction (HER) are a key constituent of a low-carbon industrial economy based on intermittent energy production in the near future. A facile wet-chemistry strategy has been developed for the synthesis of a porous Ru layer deposited onto Ni foam (NF) as a competitive candidate for HER over the whole pH range, especially under economical alkaline conditions. The catalyst shows outstanding HER performance, which stems from the porosity of the Ru layer, the electronic structure of the electrode, and the charge transfer between the NF and the Ru layer, which gives rise to the strong activity of the Ru layer in the HER process. Moreover, the Ru loading was as low as approximately 1.1 wt %, representing significant potential for application in cost-effective HER.

14.
J Nanosci Nanotechnol ; 19(9): 5838-5846, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30961747

RESUMO

In this paper, magnetic NiFe2O4-RHC (rice husk carbon) catalysts with different NiFe2O4 contents are prepared through a one-step hydrothermal method and employed as a catalyst for the reduction of nitrophenols. The resulting catalysts are characterized using various techniques. It is indicated that the NiFe2O4 nanoparticles are well dispersed on the RHC with the average size of 9.97 nm and 224.13 m²·g-1 BET surface area. NiFe2O4-RHC (0.75) has the highest activity for the reduction of nitrophenols (k = 0°8872 min-1). The combination of NiFe2O4 nanoparticles with RHC results in a dramatic conversion of the inert NiFe2O4 into a highly active catalyst for the reduction of nitrophenols at 25 °C employing NaBH4 as the reducing agent in aqueous medium. The excellent catalytic performance of NiFe2O4-RHC (0.75) may be attributed to the specific characteristics of the nanostructure and the synergistic effect between NiFe2O4 and RHC. The effect of the substituent and temperature are also investigated. The activation energy was reduced to 15.342 kJ mol-1, facilitating the reaction at lower temperature. Furthermore, the catalyst NiFe2O4-RHC (0.75) is very cheap when RHC is introduced as the support compared to other carbon materials. The catalyst also exhibits magnetic performance and good stability; it can be used for 10 successive experiments with a conversion of 96%.

15.
Nanomaterials (Basel) ; 9(3)2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30836647

RESUMO

Due to the capability of utilizing light energy to drive chemical reactions, photocatalysis has been widely accepted as a green technology to help us address the increasingly severe environment and energy issues facing human society. To date, a large amount of research has been devoted to enhancing the properties of photocatalysts. As reported, coupling semiconductors with metals is one of the most effective methods to achieve high-performance photocatalysts. The excellent properties of metal/semiconductor (M/S) nanocomposite photocatalysts originate in two aspects: (i) improved charge separation at the metal-semiconductor interface; and (ii) increased absorption of visible light due to the surface plasmon resonance of metals. So far, many M/S nanocomposite photocatalysts with different structures have been developed for the application in environmental remediation, selective organic transformation, hydrogen evolution, and disinfection. Herein, we will give a review on the M/S nanocomposite photocatalysts, regarding their fundamentals, structures (as well as their typical synthetic approaches), applications and properties. Finally, we will also present our perspective on the future development of M/S nanocomposite photocatalysts.

16.
Inorg Chem ; 57(15): 9412-9424, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30028597

RESUMO

Methane-based nitridation was employed to produce wurtzite zinc-gallium oxynitride (ZnGaNO) photocatalyst particles using Zn/Ga/CO3 layered double hydroxides (LDHs) as precursor. Introduction of methane to nitridation would promote the formation of Zn-O bonding and suppress shallow acceptor complexes such as V(Zn)-Ga(Zn) and Ga-Oi in ZnGaNO particles. On the other hand, high flow rate of methane would induce breaking of Ga-N bonding and enhance surface deposition of metallic Ga atoms. After loading with Rh and RuO2, ZnGaNO particles had free electron density in an order of S50 > S20 > S90 > S0, which correlated well with their photocatalytic performance upon visible-light irradiation. The best performance of the loaded S50 was ascribed to the relatively flat surface band bending of the particle. Methane-based nitridation of Zn/Ga/CO3 LDHs would provide a new route to tune the surface chemistry of ZnGaNO and enhance the photocatalytic performance to its full potential.

17.
Environ Sci Pollut Res Int ; 25(23): 22998-23008, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29858998

RESUMO

In this study, the effect of Fe3+, Fe2+, and Mn2+ dose, solution pH, reaction temperature, background water matrix (i.e., inorganic anions, cations, and natural organic matters (NOM)), and the kinetics and mechanism for the reaction system of Fe(VI)/Fe3+, Fe(VI)/Fe2+, and Fe(VI)/Mn2+ were investigated systematically. Traces of Fe3+, Fe2+, and Mn2+ promoted the DCF removal by Fe(VI) significantly. The pseudo-first-order rate constant (kobs) of DCF increased with decreasing pH (9-6) and increasing temperature (10-30 °C) due to the gradually reduced stability and enhanced reactivity of Fe(VI). Cu2+ and Zn2+ ions evidently improved the DCF removal, while CO32- restrained it. Besides, SO42-, Cl-, NO3-, Mg2+, and Ca2+ almost had no influence on the degradation of DCF by Fe(VI)/Fe3+, Fe(VI)/Fe2+, and Fe(VI)/Mn2+ within the tested concentration. The addition of 5 or 20 mg L-1 NOM decreased the removal efficiency of DCF. Moreover, Fe2O3 and Fe(OH)3, the by-products of Fe(VI), slightly inhibited the DCF removal, while α-FeOOH, another by-product of Fe(VI), showed no influence at pH 7. In addition, MnO2 and MnO4-, the by-products of Mn2+, enhanced the DCF degradation due to catalysis and superposition of oxidation capacity, respectively. This study indicates that Fe3+ and Fe2+ promoted the DCF removal mainly via the self-catalysis for Fe(VI), and meanwhile, the catalysis of Mn2+ and the effect of its by-products (i.e., MnO2 and MnO4-) contributed synchronously for DCF degradation. Graphical abstract ᅟ.


Assuntos
Diclofenaco/isolamento & purificação , Ferro/química , Manganês/química , Poluentes Químicos da Água/isolamento & purificação , Ânions/química , Catálise , Diclofenaco/química , Concentração de Íons de Hidrogênio , Compostos de Ferro/química , Cinética , Compostos de Manganês/química , Minerais/química , Oxirredução , Óxidos/química , Temperatura , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Purificação da Água/métodos
18.
Sci Rep ; 8(1): 712, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29335465

RESUMO

Progesterone is required for the establishment and maintenance of mammalian pregnancy and widely used for conservative treatment of luteal phase deficiency in clinics. However, there are limited solid evidences available for the optimal timing and dose of progesterone therapy, especially for the possible adverse effects on implantation and decidualization when progesterone is administrated empirically. In our study, mouse models were used to examine effects of excess progesterone on embryo implantation and decidualization. Our data indicate that excess progesterone is not only harmful for mouse implantation, but also impairs mouse decidualization. In excess progesterone-treated mice, the impaired LIF/STAT3 pathway and dysregulated endoplasmic reticulum stress may lead to the inhibition of embryo implantation and decidualization. It is possible that the decrease in birth weight of excess progesterone-treated mice is due to a compromised embryo implantation and decidualization. Furthermore, excess progesterone compromises in vitro decidualization of human endometrial stromal cells.


Assuntos
Implantação do Embrião/efeitos dos fármacos , Endométrio/efeitos dos fármacos , Endométrio/fisiologia , Progesterona/metabolismo , Progestinas/metabolismo , Animais , Estresse do Retículo Endoplasmático , Feminino , Humanos , Fator Inibidor de Leucemia , Camundongos , Fator de Transcrição STAT3 , Células Estromais/efeitos dos fármacos , Células Estromais/fisiologia
19.
Alcohol Alcohol ; 52(2): 180-189, 2017 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-28182209

RESUMO

Aims: The aim of this study was to examine the effect of alcohol on the decidualization of human endometrial stromal cells during early pregnancy. Methods: During in vitro decidualization, human endometrial stromal cells were treated with alcohol, 4-methylpyrazole hydrochloride (FPZ), the inhibitor of alcohol dehydrogenases (ADHs), and tetraethylthiuram disulfide (DSF), the inhibitor of acetaldehyde dehydrogenases (ALDHs), respectively. Cell viability and decidualization were examined. Apoptosis and proliferation were also evaluated. Results: The findings showed that ADHs and ALDHs were up-regulated during decidualization. After alcohol treatment, the cell viability of decidual stromal cells was significantly higher than control, which was abrogated by FPZ or DSF. When cells were treated with alcohol, proliferation-related signal pathways were up-regulated in decidualized cells. Additionally, FOXO1 transcriptionally up-regulates ADH1B. Conclusion: Our study provided an evidence that highly expressed ADHs and ALDHs endow decidual stromal cells an ability to alleviate the harm from alcohol.


Assuntos
Álcool Desidrogenase/biossíntese , Aldeído Oxirredutases/biossíntese , Decídua/efeitos dos fármacos , Decídua/enzimologia , Etanol/toxicidade , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Linhagem Celular Transformada , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Decídua/citologia , Feminino , Humanos , Células Estromais/citologia , Células Estromais/efeitos dos fármacos , Células Estromais/enzimologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-27455296

RESUMO

The exposure of heavy metals to lake bed sediment of scenic areas may pose risks on aquatic ecosystems and human health, however very few studies on risk assessment have been reported for scenic areas. Accordingly, this study determined concentration levels, and assessed contamination characteristics and risks, of heavy metals in lake bed sediment of National Scenic Areas Songhuahu (NSAS) in China. The concentrations of Zn, Cr, Pb, Ni, and Cu were determined in 29 bed sediment samples. Results showed that the mean values of Zn, Cr, Pb, Ni, and Cu were 92.69, 90.73, 38.29, 46.77, and 49.44 mg/kg, respectively. Pearson correlation coefficients indicated that organic matter was a major factor influencing distribution of heavy metals. The results for enrichment factors indicated that contamination rates and anthropogenic inputs of single heavy metals decreased in the order Cu > Ni > Pb > Cr > Zn; results of Nemerow integrated pollution index suggested that 72.41% of sampling sites were exposed to low to moderately integrated pollution, and 27.59% of sampling sites were exposed to strongly integrated pollution. According to results for potential ecological risk index, ecological risks of single and all the heavy metals in bed sediment from all the sampling sites were low. Human risks were assessed with hazardous quotients, and the results suggested that exposure of heavy metals to bed sediment posed no or little risk to human health, and the pathway of ingestion significantly contributed to human health risks.


Assuntos
Sedimentos Geológicos/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Humanos , Lagos , Medição de Risco
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