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Resultados 4721-4730 de 4,924
Nicotine increased VEGF and MMP2 levels in the rat eye and kidney
2019
Ateş, Mehmet | Hosgorler, Ferda | Yuksel, Oguz | Unsal, Sultan Kaya | Guvendi, Guven | Karakilic, Asli | Koc, Basar | Kandis, Sevim | Kanit, Lutfiye | Uysal, Nazan
Chronic cigarette smoking affects many tissues negatively. Nicotine in tobacco has negative effects on tissues, kidneys, and eyes especially, where microcirculation is vitally important for the survival and functioning. It is known that appropriate vascular endothelial growth factor (VEGF) and (matrix metalloproteinase 2) MMP2 levels are required for suitable vascularity and enough microcirculation. The aim of this study was to investigate the effect of nicotine on VEGF and MMP2 levels in kidney and eyes, where microcirculation is very important for their function. The nicotine was given into drinking water, to male and female rats for 6 weeks. During the first 2 weeks, the nicotine concentration was 10 mg/L, then was given at a fixed dose of 20 mg/L until the end of the experiment. The VEGF and MMP2 levels were increased in kidney tissue of both genders as a result of given nicotine. MMP2 levels were also increased in the eye tissue for both genders similarly. However, VEGF levels increased in the eye tissue with nicotine in males, whereas it did not change in females. The use of nicotine made VEGF and MMP2 levels increase in kidney tissue in both genders of rats. This increase in VEGF was observed only in male eye tissue, not in females. According to our findings, it can be suggested that nicotine has negative effects on microvascular circulation by increasing VEGF and MMP2 levels. In addition, it should be pointed out that estrogen might have protective effects on female eye tissue. Further studies are necessary to understand the complex relationship between the role of nicotine and estrogen on eye and kidney tissues.
Mostrar más [+] Menos [-]Self-build packed-bed bioreactor for rapid and effective BOD estimation
2019
Pham, Thi Thuy Phuong | Nguyen, Phuc Hoang Duy | Nguyen, Thi Thuy Van | Duong, Huynh Thanh Linh
This work demonstrated a simple, low-cost, rapid, and effective biochemical oxygen demand (BOD) estimation system based on a packed-bed bioreactor that can be easily self-built on-site at a particular wastewater treatment plant for continuous monitoring of the influent and effluent. The use of natural microbial consortium that were collected from the target wastewater and immobilized on a cheap porous carrier simply by adhesion resulted in an acceptable accuracy of over 95%. The newly developed semi-continuous operating mode with peak-type signals was shown to be able to continuously estimate BOD at a high flow rate to overcome the flow dependence of the oxygen electrode, limit clogging issues, enhance the response time, and lower the limit of detection. The resulting packed-bed bioreactors could work continuously for 22 h with a coefficient of variance (CoV) of only 1.8% or for 13 h a day for several days with a maximum CoV of 1.4% and their response was observed to be stable over 80 consecutive measurements. They exhibited stable responses at a wide pH range of 6.5–8.5, which is also the recommended range for aerobic wastewater treatment, emphasizing the greater ease of use of natural microorganisms for BOD estimation.
Mostrar más [+] Menos [-]Investigation on synthesis of ion-imprinted mesoporous adsorbents by using ultrasound- and microwave-assisted preparation and their dynamic adsorption properties on heavy metals
2019
Yang, Hong | Hu, Yanling | Wang, Xiaoyu | Fu, Weng | Tian, Huijuan | Alam, Easar
Removal of the heavy metal ions in aqueous solution is an important technology for waste water treatment. The effects of using ultrasonic and microwave on synthesizing Pb²⁺, Zn²⁺, and Cu²⁺ imprinted mesoporous adsorbents (Pb-IMA-UM, Zn-IMA-UM, and Cu-IMA-UM) and their dynamic adsorption properties were studied. The microstructure and composition of the ion-imprinted mesoporous adsorbents were discussed in detail by TEM, FTIR, N₂ adsorption-desorption, XRD, and EDS. The pore sizes of mesoporous absorbents were improved more uniformly by using ultrasonic agitation than magnetic stirring. The elution efficiency of imprinting ions can be enhanced by microwave elution. Prepared Pb-IMA-UM, Zn-IMA-UM, and Cu-IMA-UM were used for dynamic adsorption study of heavy metals. The detected optimal feed rate was 20.0 mL/min and the influent concentration was 60 mg/L; the equilibrium adsorption capacities of Pb-IMA-UM, Cu-IMA-UM, and Zn-IMA-UM could reach 198 mg/g, 51.5 mg/g, and 57.3 mg/g, respectively. The dynamic regeneration performance of the adsorbent was also investigated with the Cu-IMA-UM sample. The adsorption rate remained above 89% after five dynamic regeneration experiments. At last, the actual wastewater from an electroplating industry was used as the research object. Three groups of dynamic adsorption coefficient contours of Pb-IMA-UM, Zn-IMA-UM, and Cu-IMA-UM were obtained when influents flowed into three adsorption columns separately. The experimental results showed that an ion-imprinted adsorbent had a much better adsorption capacity of imprinted ions under the various metals mixed conditions.
Mostrar más [+] Menos [-]Biosorption of nickel(II) and copper(II) ions from synthetic and real effluents by alginate-based biosorbent produced from seaweed Sargassum sp
2019
Barquilha, Carlos E. R. | Cossich, Eneida S. | Tavares, Célia R. G. | da Silva, Edson A.
In this study, the alginate-based biosorbent produced from seaweed Sargassum sp. was used in biosorption of Ni²⁺ and Cu²⁺ ions from synthetic solutions and real electroplating effluents. Biosorption kinetics, isotherms, pH effect, thermodynamic parameters, and sorption/desorption cycles were also evaluated. Kinetic studies show the sorption equilibrium can be obtained within 180 min for Ni²⁺ ions and 360 min for Cu²⁺ ions, and the adsorption kinetics data are well described by the pseudo-second order and diffusion in spherical adsorbents. Langmuir model can be well used to describe the biosorption isotherm data. The maximum sorption capacity (qₘₐₓ) and Langmuir constant (b) were up to 1.147 mmol g⁻¹ and 1.139 L mmol⁻¹ for Ni²⁺ ions and 1.640 mmol g⁻¹ and 4.645 L mmol⁻¹ for Cu²⁺ ions. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) showed that the biosorption of Ni²⁺ and Cu²⁺ ions are predominantly a chemical phenomenon of endothermic nature, favorable, and spontaneous at the temperature ranges of 293–313 K. Partial desorption of the Ni²⁺ and Cu²⁺ ions on the biosorbent was achieved using acidic and saline eluents, allowing the biosorbent to be used in new sorption/desorption cycles. EDX analysis suggests an ion exchange mechanism between calcium ions on the biosorbent and target metals. Biosorption of Ni²⁺ and Cu²⁺ from real electroplating effluents with high concentrations of light metals becomes highly competitive, decreasing the amount of Ni²⁺ and Cu²⁺ ions biosorbed due to the ionic strength effect.
Mostrar más [+] Menos [-]Environmental and economic impacts of better cotton: a panel data analysis
2019
Zulfiquar, Sundas | Yasin, Muhammad Asim | Khuda Bakhsh, | Ali, Rafaqet | Samiullah, | Munir, Saad
Better cotton is introduced with the aim of a reduction in the use of environmentally detrimental farm inputs in order to attain sustainable cotton production. The present study is designed to assess the environmental and economic effects of better cotton in Pakistan using panel data comprising of two cropping seasons, 2015 and 2016. Panel methods were used in the present study. Findings show that better cotton increases the gross margin by 37% and yield by 9%, whereas it results in decreasing seed rate by 6%, fertilizers by 7%, pesticides by 7%, and irrigation by 14%. Since better cotton involves more labor use due to higher yield, labor increases by 3%. The study concludes that better cotton is more economically and environmentally sustainable than conventional cotton. The study suggests that public private partnership will be a good strategy to diffuse better cotton technologies among the farming communities.
Mostrar más [+] Menos [-]Numerical evaluation of pollutant emissions of a two-stroke linear engine
2019
Yuan, Chenheng | Zhang, Pengbo | Liu, Yang
Combustion engines bring a lot of pollution products to human living environment. This study introduced a green engine called free-piston linear engine (FPLE), and performed an evaluation on the pollutant emissions of a diesel FPLE by comparison with a corresponding conventional crankshaft engine (CCE). The combustion reaction and pollutant formation were described by a comprehensive model which considers the special operation mechanism of the FPLE. The effect of dynamic and fuel quantity on the unclean combustion products of the FPLE and the CCE was compared. Results indicate that in the case of the fuel quantity of 7.1 mg condition, the pollutant forming in the FPLE is generally later than that in CCE because of the higher speed of FPLE around the reverse point of stroke, and a significant advantage in nitric oxide (NO) emission is found for the FPLE, although it emits more carbon monoxide (CO) and soot. Moreover, compared with the CCE, the FPLE is cleaner in lean fuel conditions because the NO production of the FPLE is only half of that of the CCE, and that of other pollutants is almost at the same level. However, in heavy fuel conditions, the FPLE shows a disadvantage in CO and soot emission due to the serious afterburning effect and poor oxygen environment in some local areas, although its NO production is still lower than that of the CCE.
Mostrar más [+] Menos [-]Application of Beauveria bassiana spore waste as adsorbent to uptake acid red 97 dye from aqueous medium
2019
Georgin, Jordana | Alves, Eliana | Drumm, Fernanda | Tonato, Denise | Grassi, Patrícia | Piccin, Jeferson S. | Oliveira, Marcos L. S. | Dotto, Guilherme L. | Mazutti, Marcio A.
The adsorption of acid red 97 dye (RED 97) by the waste of the filamentous fungus Beauveria bassiana was analyzed. The adsorbent was obtained as a waste of a fermentative process, and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), X–ray powder diffractometry (XRD), and specific surface area (BET). After the characterization, adsorption tests were carried out to determine the ideal conditions of pH, adsorbent mass, and contact time for the process. Adsorption isotherms, thermodynamic studies, and the treatment of textile effluent were also investigated. The adsorbent characterization allowed the visualization of its amorphous structure, with irregular and heterogeneous particles. The pore diameter was 51.9 nm and the surface area was 0.247 m² g⁻¹. 1.2 g L⁻¹ of the adsorbent and pH of 2.0 were the ideal conditions for RED 97 adsorption. The pseudo–second–order kinetic model was the most appropriate to represent the experimental data, being the equilibrium reached in about 110 min. The Langmuir model was the most suitable to represent the equilibrium data, with maximum adsorption capacity of 194.1 mg g⁻¹ at 45 °C. The adsorption processes was thermodynamically spontaneous, favorable, and exothermic. In the treatment of a real textile effluent, 5 g L⁻¹ of the spores was capable to decolorize 70% of the solution. Therefore, spore wastes of Beauveria bassiana were promising for RED 97 adsorption.
Mostrar más [+] Menos [-]Overview performance of lanthanide oxide catalysts in methanation reaction for natural gas production
2019
Rosid, Salmiah Jamal Mat | Toemen, Susilawati | Iqbal, Malik Muhammad Asif | Bakar, Wan Azelee Wan Abu | Mokhtar, Wan Nur Aini Wan | Aziz, Md Maniruzzaman A.
A rapid growth in the development of power generation and transportation sectors would result in an increase in the carbon dioxide (CO₂) concentration in the atmosphere. As it will continue to play a vital role in meeting current and future needs, significant efforts have been made to address this problem. Over the past few years, extensive studies on the development of heterogeneous catalysts for CO₂ methanation have been investigated and reported in the literatures. In this paper, a comprehensive overview of methanation research studies over lanthanide oxide catalysts has been reviewed. The utilisation of lanthanide oxides as CO₂ methanation catalysts performed an outstanding result of CO₂ conversion and improvised the conversion of acidity from CO₂ gas to CH₄ gas. The innovations of catalysts towards the reaction were discussed in details including the influence of preparation methods, the structure-activity relationships as well as the mechanism with the purpose of outlining the pathways for future development of the methanation process.
Mostrar más [+] Menos [-]Impact of substrate material on algal biofilm biomass growth
2019
Venable, Mark E. | Podbielski, Melanie R.
Algae are being grown for wastewater purification and biofuels production. Their growth on a substrate facilitates these uses by allowing facile separation of algae from the water. Here, we compare different materials to determine which would best serve this purpose. A mixed culture of Anabaena and Chlorella was grown on various synthetic and natural fiber fabric substrates in a trough system with recirculating simulated wastewater. Filter materials studied as substrates for algal growth were muslin, olefin, pellon (acrylic), two types of polyester, and two types of nylon. Biomass accumulation on the various filter substrates was recorded at 7, 14, and 28 days. Filters were weighed before and after the growth periods and changes in dry biomass were recorded. Biomass accumulation was significantly affected by the fabric type. Olefin fostered the greatest increase in biomass while nylon and polyester also supported competitive increases in biomass. Pellon showed the smallest biomass increase and muslin decreased in mass due to material disintegration. Other concerns such as abrasion resistance and UV susceptibility are discussed.
Mostrar más [+] Menos [-]Occurrence, source apportionment, and potential human health risks of metal(loid)s and PAHs in dusts from driving school campuses in an urban area of Henan, China
2019
Chen, Yinan | Ma, Jianhua | Duan, Haijing | Miao, Changhong
Concentrations, health risks, and sources of 9 metal(loid)s (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn) and 16 PAHs in dusts collected from the 29 driving school campuses in the urban area of Kaifeng, Henan Province, China, were evaluated. The health risks due to exposure to these pollutants in dusts were assessed under three different scenarios (working for 10 years, 20 years, and 30 years in driving schools), using the health risk assessment model developed by US EPA. The results indicated that the mean concentrations for As, Cd, Cr, Cu, Hg, Pb, and Zn were higher than the local dust background except Co and Ni. The total PAH concentrations ranged from 198.21 to 3 400.89 μg kg⁻¹, with a mean value of 908.72 μg kg⁻¹. The dominant components were the two and three member-ring PAHs, accounting for 55.79% of the ∑PAHs, while PAHs with four to six member-rings accounted for 44.21% of total PAHs. The non-cancer risks of metal(loid)s in most samples were within the safe range except for two samples, with Pb as the major non-carcinogenic risk factor. The cancer risks of As, Cd, Cr, and Ni were also within the currently acceptable range except for one sample under two scenarios (working for 20a and 30a in a driving school). The cancer risks of PAHs in most samples were within the safe range except for one sample under scenario 3. The source identification results demonstrated that Pb, Zn, Cu, and Cd in the driving school dusts are mainly affected by the emission of driving-school vehicles. For PAHs, the typical driving school vehicle emissions were predominated by Phe and Ant, followed by Flu, Pyr, BkF, and Nap. The concentrations and health risks of the metal(loid)s and PAHs in the dusts were not significantly related to the driving school operation time or vehicle density, but closely related to the surrounding environments and the historical land uses of driving schools.
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