Mutual Inhibitory Effect Research Articles

Effect of the component and the concentration ratio on the removal of volatile organic compound mixtures by non-thermal plasma

The feasibility and efficiency of the degradation of volatile organic compounds (VOCs) by non-thermal plasma (NTP) has been extensive investigated and proved in laboratory experiments with single target component. In practical, multicomponent VOCs are emitted during industrial production. It is urgent need to study the abatement of multicomponent VOCs to evaluate the effectiveness of NTP technology in application, and explore the impact of interactions between VOCs components on degradation efficiency. This study focused on the degradation of VOCs mixtures composed of toluene (TOL), acetone (AC), and ethyl acetate (EA) by dielectric barrier discharge (DBD) plasma in room temperature. Through changing the target gas in turn and the concentration ratio of additive gas in binary mixture, the influence of the composition and the concentration ratio of the additive gases on the target gas degradation have been investigated by comparing the decomposition of the single compound. The results showed that AC and EA had little or no inhibitory effect on degradation of TOL. When AC was added and degraded together with TOL, the degradation rate of TOL remained almost unchanged with slight fluctuations in the range of 75.3 ± 1.0% as the ratio of added AC increased. However, TOL significantly inhibited the degradation of EA and AC, and more seriously on AC. When the ratio of added TOL increased, the degradation rates of EA or AC changed from 41.1% or 34.5% to 29.8% or 12.2%, which were 11.3% or 22.3% reduced respectively. It is indicated that there was a mutual inhibitory effect between the AC and EA when they were degraded together, and a stronger inhibitory effect of EA on AC was observed. When the ratio of added AC to EA changed from 0:1 to 3:1, the degradation rate of EA decreased by 9.5%, from 49.8% to 40.3%. When the ratio of added EA to AC changed from 0:1 to 3:1, the degradation rate of AC decreased by 16.0%, from 37.9% to 21.9%.

Characteristics of catalytic destruction of dichloromethane and ethyl acetate mixture over HxPO4-RuOx/CeO2 catalyst

Catalytic destruction is an ascendant technology for the abatement of volatile organic compounds (VOCs) originating from solvent-based industrial processes. The varied composition tends to influence each VOC's catalytic behavior in the reaction mixture. We investigated the catalytic destruction of multi-component VOCs including dichloromethane (DCM) and ethyl acetate (EA), as representatives from pharmaceutical waste gases, over co-supported HxPO4-RuOx/CeO2 catalyst. A mutual inhibitory effect relating to concentrations because of competitive adsorption was verified in the binary VOCs oxidation and EA posed a more negative effect on DCM oxidation owing to EA's superior adsorption capacity. Preferential adsorption of EA on acidic sites (HxPO4/CeO2) promoted DCM activation on basic sites (O2−) and the dominating EA oxidation blocked DCM's access to oxidation centers (RuOx/CeO2), resulting in boosted monochloromethane yield and increased chlorine deposition for DCM oxidation. The impaired redox ability of Ru species owing to chlorine deposition in turn jeopardized deep oxidation of EA and its by-products, leading to increased gaseous by-products such as acetic acid originating from EA pyrolysis. Notably, DCM at low concentration slightly promoted EA conversion at low temperatures with or without water, consistent with the enhanced EA adsorption in co-adsorption analyses. This was mainly due to that DCM impeded the shielding effect of hydrolysate deposition from rapid EA hydrolysis depending on the decreased acidity. Moreover, water benefited EA hydrolysis but decreased CO2 selectivity while the generated water derived from EA was likely to affect DCM transformation. This work may provide theoretical guidance for the promotion of applied catalysts toward industrial applications.

Overexpression of EphB6 and EphrinB2 controls soma spacing of cortical neurons in a mutual inhibitory way

To establish functional circuitry, neurons settle down in a particular spatial domain by spacing their cell bodies, which requires proper positioning of the soma and establishing of a zone with unique connections. Deficits in this process are implicated in neurodevelopmental diseases. In this study, we examined the function of EphB6 in the development of cerebral cortex. Overexpression of EphB6 via in utero electroporation results in clumping of cortical neurons, while reducing its expression has no effect. In addition, overexpression of EphrinB2, a ligand of EphB6, also induces soma clumping in the cortex. Unexpectedly, the soma clumping phenotypes disappear when both of them are overexpressed in cortical neurons. The mutual inhibitory effect of EphB6/ EphrinB2 on preventing soma clumping is likely to be achieved via interaction of their specific domains. Thus, our results reveal a combinational role of EphrinB2/EphB6 overexpression in controlling soma spacing in cortical development.

Investigation of the Heteroatom Doping Effect on Gasification Fine Slag Residue Carbon Oxygen Reduction Reaction Catalysts

Coal gasification fine slag (GFS) is a kind of solid waste that is produced from industrial entrained‐flow gasification plants. Using the GFS flotation residue as a carbon source for the oxygen reduction reaction (ORR) catalyst is therefore an effective recycling method that will gain great attention. Herein, the carbon residue after the flotation of GFS is used as the precursor to prepare ORR catalysts through CO2 activation. Combined with the characterization of Raman spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy, the influence of N, P, Fe, Ca, and other doped elements on the physical and chemical structure of the catalyst is explored. The results demonstrate that calcium chloride causes the decrease of reactive nitrogen, and has a negative effect on the development of pore structure. The active nitrogen content of ammonium phosphate as a nitrogen source is lower than that of ammonium chloride as a nitrogen source. The codoping of ammonium phosphate and ferrocene produces a mutual inhibitory effect, resulting in lower doping levels of phosphorus and iron. This study has great significance for the activation and heteroatom doping treatment of ORR catalysts prepared from gasification residue carbon.

MnOx catalysts with different morphologies for low temperature synergistic removal of NOx and toluene: Structure–activity relationship and mutual inhibitory effects

The simultaneous catalytic removal of nitrogen oxides (NOx) and toluene, in an existing selective catalytic reduction (SCR) unit, has drawn much attention. Exploring the interaction effects between the catalytic oxidation of toluene and the reduction of NOx is crucial to ensure the successful design and development of catalysts for their simultaneous removal. MnOx nanorod and MnOx nanocuboid were synthesized to compare their catalytic performances for the simultaneous removal of NOx and toluene. The MnOx nanorod catalyst possessed greater catalytic activity than the MnOx nanocuboid catalyst and exhibited a greater than 85% catalytic activity in the simultaneous abatement of NOx and toluene at 275 °C. The MnOx nanorod catalyst had a higher proportion of Mn4+ and a better redox ability compared with the MnOx nanocuboid, resulting in an excellent catalytic activity. Thus, it was selected as a model catalyst to investigate the interaction effects. Compared with the separate NH3-SCR and toluene oxidation reactions, there was a mutual inhibitory effect between the SCR reaction and toluene oxidation in the simultaneous removal process over the model catalyst (MnOx nanorod). This mutual inhibitory effect was investigated systematically using TPD, GC-MS and in situ DRIFTs. Mutual inhibitory effect over the model catalyst mainly manifested as follows: 1) the formation of intermediate products in the oxidation process of toluene covered the active sites; 2) the competitive adsorption of NH3 and toluene occurred; and 3) the SCR reaction and toluene oxidation process competed for reactive oxygen species.

Adsorption/desorption of naphthalene and phenanthrene in a binary competitive system in the riparian zone

Polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (Nap) and phenanthrene (Phe) are organic pollutants that are of concern because of their environmental toxicity. Adsorption is a promising process for the removal of Nap and Phe from water and soil. The riparian zone between a river and a riparian aquifer, which is rich in adsorption medium, may be important for PAH remediation. Nap and Phe may be removed from the surface water through adsorption by the media in the riparian zone. However, there is still a lack of the removal patterns and mechanisms of media in the riparian zone to remediate water contaminated by Nap and Phe simultaneously. In this study, focusing on the typical PAHs (Nap and Phe) as target pollutants, batch static adsorption and desorption experiments of Nap and Phe were carried out to explore the competitive adsorption mechanisms of Nap and Phe in the binary system. Batch dynamic adsorption experiments were conducted to ascertain the adsorption regulation of Nap and Phe in sediments during the recharge of groundwater by river water in a riparian zone. The static adsorption experiment results showed that competitive adsorption of Nap and Phe occurred, and a mutual inhibitory effect of Nap and Phe adsorption was observed in the binary system. Phe had a stronger inhibitory effect on Nap, Phe was preferentially adsorbed on the medium in binary adsorption. The results of batch dynamic experiments showed that, in terms of adsorption, the riparian zone in the study area showed stronger performance for removal of Phe than Nap. The results of this paper could be useful for alleviating Nap and Phe pollution of groundwater and developing treatment protocols for groundwater exposed to Nap and Phe.

Examination of the molecular mechanism of the mutual inhibitory effect of each cytotoxicity caused by the combined extraction of Coptidis Rhizoma and Rhei Rhizoma: An example of providing evidence for ‘herbal pair’ theory

ABSTRACTAimKampo medicines are effective depending on the combination of crude drugs. In addition, the basis is a combination of two crude drugs, which is defined as a ‘herbal pair’. However, there are very few studies from this point of view. We found that Rhei Rhizoma (RR) may interact with Coptidis Rhizoma (CR).MethodsComponent profiles were analyzed by three‐dimensional high‐performance liquid chromatography (3D‐HPLC). Cell viability in N18TG‐2 cells was determined by morphology observation and a ‘3‐(4,5‐di‐methylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, yellow tetrazole (MTT)’ assay.ResultsWhen RR and CR were extracted together, the color of the extract was lighter than the colors of the individual extracts. In addition, precipitation occurred by simply combining the extracts of both in vitro. When each component profile was analyzed by 3D‐HPLC, at least the amount of berberine, which is contained in a large amount in CR, was strongly decreased in combined extracts with RR. Although CR and RR each have a cytotoxic effect, when both were extracted together, their cytotoxicity almost disappeared. However, cytotoxicity remained in the supernatant when both extracts were combined in vitro, and also in the suspension of the resulting precipitate.ConclusionFrom these results, when CR and RR are extracted together, their cytotoxicity is suppressed by some unknown mechanism. Whether this is due to the synthesis of new compounds by co‐extraction or the detoxification of toxic components by interaction needs further investigation. This result suggests the importance of ‘herbal pair’ research.

Upregulation of Long Noncoding RNA FGD5-AS1 Ameliorates Myocardial Ischemia/Reperfusion Injury via MicroRNA-106a-5p and MicroRNA-106b-5p.

Long noncoding RNAs have been known to play key roles in myocardial ischemia/reperfusion injury. This study was conducted to investigate whether upregulation of FGD5-AS1 can improve hypoxia/reoxygenation (H/R) injury of cardiomyocytes and its underlying mechanisms. Pc-FGD5-AS1 was used to overexpress FGD5-AS1 in cardiomyocytes. Cholecystokinin octapeptide and flow cytometry assays were performed to detect the effect of FGD5-AS1 on myocardial cell H/R injury. Quantitative real-time polymerase chain reaction and luciferase reporter assay were performed to assess the relationship between FGD5-AS1 and microRNA-106a-5p (miR-106a-5p) or miR-106b-5p. In patients with acute myocardial infarction and in H/R cardiomyocytes and ischemia/reperfusion myocardium, the expression levels of FGD5-AS1 were reduced, whereas the expression levels of miR-106a-5p and miR-106b-5p were increased. Overexpression of FGD5-AS1 increased the viability of H/R-treated cardiomyocytes and reduced the levels of apoptosis and creatine kinase-MB. In addition, FGD5-AS1 could bind to miR-106a-5p or miR-106b-5p and showed a mutual inhibitory effect between them. Furthermore, overexpression of miR-106a-5p or miR-106b-5p inhibited the expression of SMAD5. FGD5-AS1 upregulated the expression of SMAD5. In conclusion, FGD5-AS1 may be a potential therapeutic target for myocardial H/R injury, and its cardioprotective effect may be realized by reducing inflammatory response and cell apoptosis.

Experimental Study on Morphological Characteristics of Ventilated Supercavity of Double Disc Cavitator Projectile

Based on the principle of independence of cavity sections expansion, a double disc cavitator for underwater projectiles is proposed in this paper.The high-speed water tunnel experiment is carried out to study the generation and morphological characteristics of the ventilated supercavity which generated by this series of double disc cavitator.The experiment observed the ventilated supercavity morphology under the different cone angles by changing the ventilation flow coefficient.The experimental results show that there are two kinds of cavitation states:the front disc preferential cavitation and the rear disc preferential cavitation. The transition between these two states occur at a cone angle about 55°.The value of the critical ventilation flow coefficient when generating stable ventilation supercavity has a positive correlation with the cone angle.The front disc and the rear disc of the cavitator have mutual inhibitory effect on the production of ventilated supercavities.And the morphological characteristics of ventilated supercavity do not increase with the increasing of ventilation flow coefficient, but there is an upper limit value of ventilation flow coefficient.

High-speed photographic observation of collapse of two cavitation bubbles

Cavitation as a hydrodynamic phenomenon exists widely in water conservancy, shipbuilding, chemical and many other industries. Previous cavitation bubble dynamic studies mainly focused on single cavitation bubbles and their interaction with the wall. This paper studies the interaction between two cavitation bubbles under conditions with or without a wall. The results show that if the inception of two cavitation bubbles is not synchronized, the cavitation bubble of early inception collapse backwards the cavitation bubble of later inception; if the inception of two cavitation bubbles is synchronized, the two bubbles collapse towards each other; if a wall exists nearby, no matter whether the line connecting the centers of the two cavitation bubbles is vertical or parallel to the wall, the two cavitation bubbles collapse towards each other and then gradually merge, and the merged collapse body quickly moves to the wall. It is suggested that, as the number of cavitation bubbles increases, the cavitation erosion effect is not simply increased proportionally. Instead, mutual inhibitory effect may be demonstrated.

PXR interaction with p53: a meeting of two masters.

PXR interaction with p53: a meeting of two masters.

Crucial role of alkaline sphingomyelinase in sphingomyelin digestion: a study on enzyme knockout mice

Alkaline sphingomyelinase (alk-SMase) hydrolyses sphingomyelin (SM) to ceramide in the gut. To evaluate the physiological importance of the enzyme, we generated alk-SMase knockout (KO) mice by the Cre-recombinase-Locus of X-over P1(Cre-LoxP) system and studied SM digestion. Both wild-type (WT) and KO mice were fed ³H-palmitic acid labeled SM together with milk SM by gavage. The lipids in intestinal content, intestinal tissues, serum, and liver were analyzed by TLC. In KO mice, nondigested ³H-SM in the intestinal content increased by 6-fold and the formation of ³H-ceramide decreased markedly, resulting in 98% reduction of ³H-ceramide/³H-SM ratio 1 h after gavage. The absorbed ³H-palmitic acid portion was decreased by 95%. After 3 h, a small increase in ³H-ceramide was identified in distal intestine in KO mice. In feces, ³H-SM was increased by 243% and ceramide decreased by 74% in the KO mice. The KO mice also showed significantly decreased radioactivity in liver and serum. Furthermore, alkaline phosphatase activity in the mucosa was reduced by 50% and histological comparison of two female littermates preliminarily suggested mucosal hypertrophy in KO mice. This study provides definite proof for crucial roles of alk-SMase in SM digestion and points to possible roles in regulating mucosal growth and alkaline phosphatase function.

Mixture effects during the oxidation of toluene, ethyl acetate and ethanol over a cryptomelane catalyst

The catalytic oxidation of two-component VOC mixtures (ethanol, ethyl acetate and toluene) was studied over cryptomelane. Remarkable mixture effects were observed on the activity and the selectivity. Toluene inhibits both ethyl acetate and ethanol oxidation, this effect being more evident in the case of ethyl acetate. For instance, the temperature for 100% conversion is about 210 °C when ethyl acetate is oxidised alone, and 250 °C or higher, when it is oxidised in mixtures with toluene. On the contrary, toluene oxidation is only slightly inhibited by the presence of ethyl acetate, while the presence of ethanol has a promoting effect. Concerning the mixtures of ethyl acetate and ethanol, both compounds have a mutual inhibitory effect, which is more evident in the case of ethyl acetate (the temperature for 100% conversion of ethyl acetate is about 45 °C higher when ethyl acetate is oxidised in mixtures with ethanol, while in the case of ethanol the corresponding increase is only 10 °C).

Catalytic combustion of VOCs over a series of manganese oxide catalysts

Catalytic combustion of volatile organic compounds (VOCs: benzene and toluene) was studied over manganese oxide catalysts (Mn3O4, Mn2O3 and MnO2) and over the promoted manganese oxide catalysts with alkaline metal and alkaline earth metal. Their properties and performance were characterized by using the Brunauer Emmett Teller (BET), temperature programmed reduction (TPR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The sequence of catalytic activity was as follows: Mn3O4>Mn2O3>MnO2, which was correlated with the oxygen mobility on the catalyst. Each addition of potassium (K), calcium (Ca) and magnesium (Mg) to Mn3O4 catalyst enhanced the catalytic activity of Mn3O4 catalyst. Accordingly, K, Ca and Mg seemed to act as promoters, and the promoting effect might be ascribed to the defect-oxide or a hydroxyl-like group. A mutual inhibitory effect was observed between benzene and toluene in the binary mixture. In addition, the order of catalytic activity with respect to VOC molecules for single compound is benzene>toluene, and the binary mixture showed the opposite order of toluene>benzene.

Absorption and lipoprotein transport of sphingomyelin

Dietary sphingomyelin (SM) is hydrolyzed by intestinal alkaline sphingomyelinase and neutral ceramidase to sphingosine, which is absorbed and converted to palmitic acid and acylated into chylomicron triglycerides (TGs). SM digestion is slow and is affected by luminal factors such as bile salt, cholesterol, and other lipids. In the gut, SM and its metabolites may influence TG hydrolysis, cholesterol absorption, lipoprotein formation, and mucosal growth. SM accounts for approximately 20% of the phospholipids in human plasma lipoproteins, of which two-thirds are in LDL and VLDL. It is secreted in chylomicrons and VLDL and transferred into HDL via the ABCA1 transporter. Plasma SM increases after periods of large lipid loads, during suckling, and in type II hypercholesterolemia, cholesterol-fed animals, and apolipoprotein E-deficient mice. SM is thus an important amphiphilic component when plasma lipoprotein pools expand in response to large lipid loads or metabolic abnormalities. It inhibits lipoprotein lipase and LCAT as well as the interaction of lipoproteins with receptors and counteracts LDL oxidation. The turnover of plasma SM is greater than can be accounted for by the turnover of LDL and HDL particles. Some SM must be degraded via receptor-mediated catabolism of chylomicron and VLDL remnants and by scavenger receptor class B type I receptor-mediated transfer into cells.

Zn?Ni and Zn?Fe alloy deposits modified by P incorporation: anticorrosion properties

Zn–Ni–P and Zn–Fe–P alloys were electrodeposited on carbon steel plates and their morphology, composition and structure were evaluated as a function of electrolyte composition and pH. A mutual inhibitory effect between Zn and P co-deposition was observed. Amorphous alloys were only obtained with high Ni or Fe contents. Conversely, crystalline alloys presented high Zn contents. From this preliminary analysis electrodeposition conditions were selected to produce P-containing alloy coatings. Their corrosion properties were evaluated by means of a cyclic corrosion test in comparison with the corresponding P-free alloy coatings with and without an epoxy painting system. Crystalline Zn–Ni–P presented a remarkable performance, due to morphology changes in the alloy as a result of the effects of P compounds in the electrolyte. This alloy efficiently avoided corrosion propagation around an intentional defect in the painting layer. The corrosion behavior of amorphous Zn–Fe–P was similar to Zn–Fe. On the other hand, crystalline Zn–Fe–P presented the fastest corrosion rate. Corrosion propagation around the painting defect was better held by amorphous Zn–Fe–P due to an improved adhesion between painting and alloy layers. The presence of P in Zn alloys may effectively improve their anticorrosive properties. However, this phenomenon seems to be beyond the simple amorphism of the deposit.

Zn–Ni and Zn–Fe alloy deposits modified by P incorporation: anticorrosion properties

Zn–Ni–P and Zn–Fe–P alloys were electrodeposited on carbon steel plates and their morphology, composition and structure were evaluated as a function of electrolyte composition and pH. A mutual inhibitory effect between Zn and P co-deposition was observed. Amorphous alloys were only obtained with high Ni or Fe contents. Conversely, crystalline alloys presented high Zn contents. From this preliminary analysis electrodeposition conditions were selected to produce P-containing alloy coatings. Their corrosion properties were evaluated by means of a cyclic corrosion test in comparison with the corresponding P-free alloy coatings with and without an epoxy painting system. Crystalline Zn–Ni–P presented a remarkable performance, due to morphology changes in the alloy as a result of the effects of P compounds in the electrolyte. This alloy efficiently avoided corrosion propagation around an intentional defect in the painting layer. The corrosion behavior of amorphous Zn–Fe–P was similar to Zn–Fe. On the other hand, crystalline Zn–Fe–P presented the fastest corrosion rate. Corrosion propagation around the painting defect was better held by amorphous Zn–Fe–P due to an improved adhesion between painting and alloy layers. The presence of P in Zn alloys may effectively improve their anticorrosive properties. However, this phenomenon seems to be beyond the simple amorphism of the deposit.

Competitive relationships between two water plant species: Najas marina L. and Myriophyllum spicatum L.

The interrelationships between two submerged macrophytes, Najas marina and Myriophyllum spicatum, were investigated. Double-reciprocal analysis was used to distinguish between the possible types of negative relationships. Results have demonstrated that interspecific inhibition was more severe than the intraspecific one. The intensity of inhibition was negatively correlated with the density of the examined species. The mutual inhibitory effect and the pattern of the obtained results suggest that competitive relationships exist between Najas marina and Myriophyllum spicatum.

Biosorption of Heavy Metals by Bacteria Isolated from Activated Sludge

Twelve aerobic bacteria from activated sludge were isolated and identified. These included both Gram-positive (e.g., Bacillus) and Gram-negative (e.g., Pseudomonas) bacteria. The biosorption capacity of these strains for three different heavy metals (copper, nickel, and lead) was determined at pH 5.0 and initial metal concentration of 100 mg/L. Among these 12 isolates, Pseudomonas pseudoalcaligenes was selected for further investigation owing to its high metal biosorption capacity. The lead and copper biosorption of this strain followed the Langmuir isotherm model quite well with maximum biosorption capacity (q(max)) reaching 271.7mg of Pb2+/g of dry cell and 46.8 mg of Cu2+/g of dry cell at pH 5.0. Study of the effect of pH on lead and copper removal indicated that the metal biosorption increased with increasing pH from 2.0 to 7.0. A mutual inhibitory effect was observed in the lead-copper system because the presence of either ion affected the sorption capacity of the other. Unequal inhibitions were observed in all the nickel binary systems. The increasing order of affinity of the three metals toward P. pseudoalcaligenes was Ni < Cu < Pb. The metal biosorptive potential of these isolates, especially P. pseudoalcaligenes, may have possible applications in the removal and recovery of metals from industrial effluents.

A mutual inhibitory effect on absorption of sphingomyelin and cholesterol

Several studies have shown that there is a strong physical interaction between cholesterol and sphingomyelin (SM). The critical factor is thought to be the high degree of saturation in the very long acyl chains of SM. In this study we examined the effects of SM on cholesterol absorption in the rat and compared them with those of phosphatidylcholine (PC). Cholesterol absorption was studied by use of the dual-isotope plasma ratio method. We also studied the effect of sterols on the fecal excretion of undigested SM and its metabolites after a single oral meal of 3H-dihydrosphingosine-labeled SM. When cholesterol was given dissolved in soybean oil, without addition of SM or other phospholipids, absorption was 68 ± 12% in the rat intestine. As a general feature the absorption was less efficient from the cholesterol/phospholipid dispersions. In dispersions with cholesterol and SM, the lowest cholesterol absorption (9 ± 2%) was seen with a cholesterol:SM molar ratio of 1:1. With dispersions of cholesterol and different PC substrates the absorption of cholesterol was lower with saturated PC (16 ± 8%) than with soybean-PC (22 ± 4%) or dioleoyl PC (23 ± 8%). Uptake of SM in the rat intestine was reduced by sterols. For example, percentage recovery of 3H radioactivity in fecal lipids was 38 ± 8% when SM was given with cholesterol and 16 ± 3% without any sterol. One third of the radioactivity in feces was present as ceramide. Sitostanol had the same effect on uptake of SM as cholesterol. This study shows that when rats are fed mixtures of SM and cholesterol the intestinal uptake of both lipids is decreased. By feeding mixtures of SM and sterols the exposure of the colon to ceramide can be increased.