خيارات البحث
النتائج 6401 - 6410 من 6,546
Herbal syrup from chicory and artichoke leaves ameliorate liver damage induced by deltamethrin in weanling male rats النص الكامل
2020
Mohafrash, Samia Mostafa Mohamed | Mossa, Abdel-Tawab Halim
Pyrethroid insecticides are extensively used for control insects in both public health and agriculture sectors. Despite the important role of these insecticides, it caused adverse toxic effects on human, especially at the weanling stage. In this work, the antioxidant activity of chicory and artichoke leaves extracts, and phenolic flavonoid contents were studied. In addition, herbal syrup formulation and hepatoprotective effect against oxidative stress, lipid peroxidation, and liver damage induced by deltamethrin in weanling male rats were investigated. Both extracts have high phenolic, flavonoid contents, and antioxidant activity. Deltamethrin reduced body and liver weights of weanling rats. It induced oxidative stress, lipid peroxidation, and altered liver function enzymes. It caused a histopathological alteration in liver tissue. Supplementation of herbal syrup improved the above changes via increase body weights, antioxidant enzymes, and decrease lipid peroxidation, and enhanced histopathological profile. It can be concluded that herbal syrup of chicory and artichoke leaves extracts can ameliorate liver damage induced by deltamethrin. Herbal syrup from agriculture wastes of chicory and artichoke leaves is considered an easy, economical, and useful formulation for protecting agriculture workers against the adverse effects induced by pyrethroid insecticides especially in poor rural in developing countries where pyrethroid insecticides are applied for control vector-borne diseases and insects in agriculture.
اظهر المزيد [+] اقل [-]Acoustic sound–induced stress response of Nile tilapia (Oreochromis niloticus) to long-term underwater sound transmissions of urban and shipping noises النص الكامل
2020
Kusku, Halit
Human-made impacts on the acoustic environment from marine industries is becoming a more significant issue with increasing public concern of environmental consequences. Even though there are several reports with scientific evidences on harmful influences of anthropogenic underwater sounds on the aquatic ecosystem, most of the studies so far dealt with trigger effects of short term noise impacts on aquatic animals. In the present study, however, long-term experimentation was conducted with Nile tilapia (Oreochromis niloticus) in order to figure out how fish may respond to long-term exposure of underwater sounds and if the level of response may change (increase or decline) over time. A startle reflex as a sign of stress was seen immediately at the start of the playbacks of ship noise or urban sounds in this study. Peaks of elevated respiratory movements of ventilation (opercula beats and pectoral wing rates) retained high over the following 30 days of sound initiation and underwent a declining trend over the following 90 days of exposure. At the end of the 120-day study period, the lowered response of fish after long-term sound exposure is likely due to the increased tolerance of fish to human-generated underwater sounds of urban and shipping noises. Different than short-term noise impacts, information on long-term exposure of anthropogenic underwater sounds is important for environmental management and setting new regulations for the sustainable use of water resources in the world.
اظهر المزيد [+] اقل [-]Mercury and its form in a dammed reservoir ecosystem during the charging phase النص الكامل
2020
Mir, Yaseen | Wu, Shengjun | Ma, Maohua | Mangwandi, Chirangano | Mirza, Zakaria Ahmed
Throughout continents, reservoirs tend to have elevated methylmercury (MeHg) concentration transformed from mercury (Hg/total Hg). This impact may be pronounced in the reservoir with less velocity of water during the charging period resulted in the deposition of sediments. In sediments on favorable conditions, methylation may be enhanced by the decomposition of flood organic material, which can release Hg and enhance microbial activity. However, much less is known about the transfer ratio of Hg and its form MeHg from sediment to biota in the hydrological reservoir during the dam charging phase. The objective of our study was to understand the interrelationship between total Hg and MeHg in two key components sediment and fish in the reservoir ecosystem. This study was performed at the Three Gorges Reservoir (TGR) located on upstream of the Yangtze River in China. At the TGR charging phase, during winter time, the water level was high due to blockade of water by Three Gorges Dam (TGD). Sediment and fish samples were collected in winter season for total Hg, MeHg, and several ancillary parameters. The results showed that total Hg in sediment samples of the winter season were ranged from 6.2 ± 0.001 to 193.3 ± 0.001 × 10⁻³ mg/kg, with an average value of 53.76 ± 51.80 × 10⁻³ mg/kg, and for MeHg was ranged from 12.1 ± 0.04 to 348.7 ± 0.16 × 10⁻² ng/g, with an average value of 98.96 ± 93.07 × 10⁻² ng/g. Total Hg and MeHg in fish samples of the winter season were from 42.48 ± 6.71 to 166 ± 52.56 ng/g, with an average value of 76.22 ± 31.23 ng/g, and from 21.09 ± 2.31 to 61.60 ± 13.30 ng/g, with an average value of 37.89 ± 11.96 ng/g. The relationship of total Hg and MeHg concentrations in fish to those of sediments from corresponding sites showed a negative relationship. This might include a strong association of total Hg with an inorganic component of sediment (e.g., bound to sulfides or coprecipitated with other metal oxides such as manganese and iron). The average concentration of fish MeHg found in this study, at rates greater than 1.72 g/day, was estimated hazardous to human health. This study concludes sediment was acting as sequestrate for total Hg and MeHg in TGR. The bioaccumulation of total Hg and MeHg in fish was not controlled by sediment further investigation about pathological routes and dietary habits of fish needed to be identified for total Hg and MeHg study in TGR.
اظهر المزيد [+] اقل [-]Elaboration of novel polyaniline@Almond shell biocomposite for effective removal of hexavalent chromium ions and Orange G dye from aqueous solutions النص الكامل
2020
Hsini, Abdelghani | Essekri, Abdelilah | Aarab, Nouh | Laabd, Mohamed | Ait Addi, Abdelaziz | Lakhmiri, Rajae | Albourine, Abdallah
A novel polyaniline@Almond shell (PANI@AS) biocomposite was synthesized via facile in situ chemical polymerization method. The as-synthesized adsorbent was characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and potentiometric titration. A batch adsorption system was applied with the aim of investigating as-synthesized adsorbent ability to remove Cr(VI) ions and Orange G (OG) textile dye from aqueous solutions. Obtained results revealed that adsorption process was strongly depended upon the physicochemical parameters. The adsorption of Cr(VI) and OG dye onto PANI@AS was better described by the pseudo second-order-kinetic model and followed the Freundlich isotherm model. The maximum uptakes were 335.25 for Cr(VI) and 190.98 mg g⁻¹ for OG dye. We further evaluated that PANI@AS biocomposite could be regenerated easily with NaOH solution and efficiently reused for Cr(VI) and OG dye removal from aqueous media. Thus, these results indicated the potential practical application of PANI@AS biocomposite for wastewater treatment.
اظهر المزيد [+] اقل [-]Ultraviolet photolysis of metformin: mechanisms of environmental factors, identification of intermediates, and density functional theory calculations النص الكامل
2020
Lin, Wenting | Zhang, Xiaohan | Li, Ping | Tan, Yongzhen | Ren, Yuan
As a commonly used anti-diabetic drug, metformin (MEF) is frequently detected in different water bodies which pose a potential threat to human health and the ecological environment. In this study, oxidative degradation of MEF under ultraviolet (UV) light was studied, and its influencing factors, photolysis mechanism, and intermediates identification carried out as well. The results showed that the hydroxyl radical contributed 73% during the 6 h MEF photolysis process among the reactive oxygen species (ROS). In addition, triplet excited-state organic matter and singlet oxygen also played a role in the photolysis process. The reaction rates of hydroxyl radical and singlet oxygen with MEF are (6.45 ± 0.4) × 10⁹ and (5.4 ± 0.7) × 10⁶ L·(mol s)⁻¹, respectively. By calculating the light screening effect of environmental factors, it is found that the presence of NO₃⁻ and Cl⁻ had a greater excitation effect on ROS than the screening effect, and generally promoted the photolysis rates of MEF from 90.3 to 193.5% and from 16.1 to 80.6% during the 6-h reaction process, respectively. For bicarbonate and fulvic acid, the light screening effects were dominant and inhibited photolysis rates by 10–52% and 13–71%, respectively. The results demonstrated that the photoreactivity of environmental factors in water is the cause of the different photodegradation rates of MEF. The oxidative degradation product of MEF under UV light was detected by UPLC/Q-TOF as methylbiguanide (MBG), 2,4-diamino-1,3,5-triazine (2,4-DAT), biguanide (BGN), 1,1-dimethylguanidine (1,1-DiMBG), 4-amino-2-imino-1-methyl-1,2-dihydro-1, 3,5-triazine (4,2,1-AIMT), and 2-amino-4-methylamino-1,3,5-triazine (2,4-AMT). The result which showed that the primary sites of ∙OH attacked is consistent with that of density functional theory calculation. Graphical abstract
اظهر المزيد [+] اقل [-]Dynamic analysis of green investment decision of manufacturer النص الكامل
2020
Zhu, Xiaowen | Du, Jianguo | Boamah, Kofi Baah | Long, Xingle
With the continuous development of green manufacturing concept, more and more enterprises attempt to increase their green investment to promote the utilization of resources. In order to help enterprises make the optimal green investment decision, firstly, this paper constructs a duopoly competition game model based on the manufacturer’s limited rationality. Then, the Nash equilibrium solution of the system is discussed by using the reverse induction method. Finally, the system is simulated to study the green input decision and the impact of green input cost on the manufacturer’s output and profit. By adding external control signals, the chaos state of duopoly competition game model is restrained. The results show that the manufacturer’s optimal green investment portfolio lies in the stable region of Nash equilibrium. Secondly, in the duopoly competition game model, when the initial value of green input adjustment rate and cost changes slightly, the evolution of production and profit of manufacturing enterprises will be greatly different. Thirdly, the study revealed that the addition of external control signals can effectively control the chaotic situation of the market and subsequently restore the order of the participants and the market. Therefore, our research provides a reference for enterprises to make green input decision; improve the efficiency and rationality of enterprise management and further promote the green development of enterprises.
اظهر المزيد [+] اقل [-]Energy recovery from waste printed circuit boards using microwave pyrolysis: product characteristics, reaction kinetics, and benefits النص الكامل
2020
Huang, Yu-Fong | Lo, Shang-Lien
Energy recovery from waste printed circuit boards (PCBs) was carried out by using microwave pyrolysis. According to thermogravimetric analysis, the maximum weight loss rate of waste PCBs occurred at 323 °C. When waste PCBs was heated under microwave irradiation at 300 W, the temperature can be reached within 10 min. Compared with conventional pyrolysis, microwave pyrolysis can provide higher weight loss of waste PCBs by 3–5 wt%. Microwave pyrolysis is helpful for the delamination of waste PCBs. Almost 71% of the gaseous product can be directly used as a fuel or converted into other forms of energy. Microwave pyrolysis can produce more HBr than conventional pyrolysis by approximately 17%. The main components of liquid product were phenols and phenyls. The overall energy recovery from waste PCBs using microwave pyrolysis can be 62%. According to kinetic analysis, it would need 20 min of processing time to decompose the combustible fraction of waste PCBs at 300 W. The maximum processing capacity of the microwave pyrolysis system for waste PCBs can be 1.36 kg, with the energy production of 2710 kJ. Furthermore, the pyrolyzed PCBs can be further processed to recycle valuable metals. Therefore, microwave pyrolysis of waste PCBs can be a complete and effective circular economy system to create high energy and economic benefits.
اظهر المزيد [+] اقل [-]Chlorpyrifos effects on integrin alpha v and beta 3 in implantation window phase النص الكامل
2020
Gheibi, Parisa | Eftekhari, Zohre | Doroud, Delaram | Parivar, Kazem
Chlorpyrifos (CPF), as a worldwide pesticide, can effect on the integrins αv and β3 which play a main role in the implantation window. Therefore, the aim of this study was to consider CPF effects on integrin alpha v and beta 3 in implantation window phase. Thirty female NMRI mice were separated into groups of CPF, sham, and control. After 6 weeks, each group was mated, and on the 5th day of gestation, all mice were euthanized. Estradiol and progesterone levels were detected by the enzyme-linked immunosorbent assay (ELISA) test; two subunits of integrins (αv and β3) genes and proteins of endometrium were analyzed by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry method, respectively. Fibrosis of the liver which evaluated by Masson’s trichrome stain was increased in the CPF group compared with the others. But estradiol and progesterone levels were significantly decreased in CPF groups. Based on the findings, the proportion of genes’ expressions of integrin subunits declined by the effect of CPF, while there was not any notable consequence on mice in the sham group. Alpha v and beta 3 integrin proteins expressed in all groups, but the concentration of these proteins in CPF groups was lower than in other groups. This study has shown that the decline of estradiol and progesterone downregulates the expression of αv and β3 integrins which were influenced by CPF exposure. Changing these patterns of proteins could have numerous influences on unsuccessful implantation. Therefore, this experimental study recommends that inclusive consideration of the effects of insecticides may be crucial to women’s unrecognized cause of infertility.
اظهر المزيد [+] اقل [-]Analyzing the association between innovation, economic growth, and environment: divulging the importance of FDI and trade openness in India النص الكامل
2020
Zameer, Hashim | Yasmeen, Humaira | Zafar, Muhammad Wasif | Waheed, Abdul | Sinha, Avik
The objective of this paper is to explore the nexus of innovation–environment and economic growth in the context of the Indian economy. To achieve the study objective, we explored the role of technological innovation, FDI, trade openness, energy use, and economic growth toward carbon emissions. Using the data of 1985–2017, the study employed ARDL bound testing and vector error correction model (VECM) methods to capture the effects of technological innovation, trade openness, FDI, energy use, and economic growth on CO₂ emissions. Empirical estimation has confirmed the existence of long-run cointegration. Similarly, in the long run, it is found that trade openness, energy use, and economic growth positively reinforce CO₂ emissions. In contrast, technological innovation and FDI negatively reinforce CO₂ emissions in the long run. Furthermore, VECM indicates that the relationship among innovation, trade openness, and energy use is bidirectional in the long run. Whereas, unidirectional relation has been found that is coming from GDP to carbon emissions, FDI, innovation, trade, and energy use. In the short run, unidirectional link found which is coming from FDI, innovation, and energy use to carbon emission. However, the association between emissions and trade openness is bidirectional. The conclusions put forward policy implications that innovation is a way to reduce environmental degradation.
اظهر المزيد [+] اقل [-]Overview on GHG emissions of raw milk production and a comparison of milk and cheese carbon footprints of two different systems from northern Spain النص الكامل
2020
Laca, Amanda | Gómez, Natalia | Laca, Adriana | Díaz, Mario
Milk production has been estimated to contribute 3–4% of anthropogenic greenhouse gas (GHG) emissions. However, the carbon footprint associated with raw milk can vary, depending on a variety of factors, such as the geographical area, species of cow and production system. In this study, a global overview of research published on the carbon footprint (CF) of raw cow milk is provided. Additionally, two different dairy systems (semi-confinement and pasture-based) have been analysed by life-cycle assessment (LCA) in order to determine their effect on the CF of the milk produced. Inventory data were obtained directly from these facilities, and the main factors involved in milk production were included (co-products, livestock food, water, electricity, diesel, cleaning elements, transport, manure and slurry management, gas emissions to air etc.). In agreement with reviewed literature, it was found that the carbon footprint of milk was basically determined by the cattle feeding system and gas emissions from the cows. The values of milk CF found in the systems under study were within the range for cow milk production worldwide (0.9–4.7 kgCO₂eq kgFPCM⁻¹). Specifically, in the semi-confinement and the pasture-based dairy farms, 1.22 and 0.99 kgCO₂eq kgFPCM⁻¹ were obtained, respectively. The environmental benefits obtained with the pasture grazing system are not only mainly due to the lower use of purchased fodder but also to the allocation between milk and meat that was found to be a determining methodological factor in CF calculation. Finally, data from the evaluated dairy systems have been employed to analyse the influence of raw milk production on cheese manufacturing. With this aim, the CF of a small-scale cheese factory has also been obtained. The main subsystems involved (raw materials, water, electricity, energy, cleaning products, packaging materials, transport, wastes and gas emissions) were included in the inventory of the cheese factory. CF values were 16.6 and 14.7 kgCO₂eq kg⁻¹ of cheese for milk produced in semi-confinement and pasture-based systems, respectively. The production of raw milk represented more than 60% of CO₂eq emissions associated with cheese, so the primary production is the critical factor in reducing the GHG emissions due to cheese making.
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