خيارات البحث
النتائج 5411 - 5420 من 6,560
Fucoidan protects against subacute diazinon-induced oxidative damage in cardiac, hepatic, and renal tissues النص الكامل
2020
Abdel-Daim, Mohamed M. | Abushouk, Abdelrahman Ibrahim | Bahbah, Eshak I. | Bungău, Simona G. | Alyousif, Mohamed S. | Aleya, Lotfi | Alkahtani, Saad
Fucoidans (FUC) are organic sulfated polysaccharides from natural seaweeds with multiple biological actions. The current study was performed to assess the chemoprotective, antioxidant, and anti-inflammatory effects of FUC from Laminaria japonicum against diazinon (DZN)-induced injuries to rat cardiac, hepatic, and renal tissues. Forty male Wistar rats were assigned into five groups, receiving saline, oral FUC 200 mg/kg/day, subcutaneous DZN 20 mg/kg/day, DZN plus FUC 100 mg/kg/day, or DZN plus FUC 200 mg/kg/day (each treatment was given daily for 4 weeks). Data analysis showed that DZN-intoxicated rats exhibited significantly higher (p < 0.05) serum levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, urea, creatine, creatine kinase, creatine kinase-MB, lactate dehydrogenase, cholesterol, interleukin-6, and tumor necrosis factor-α, as well as lower levels of acetylcholinesterase, compared to control rats. In addition, DZN intoxication was associated with significantly higher (p < 0.05) cardiac, hepatic, and renal tissue concentrations of malondialdehyde and nitric oxide, as well as lower glutathione concentrations, and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in comparison to control rats. Treatment with FUC (at 100 or 200 mg/kg/day) ameliorated all the aforementioned alterations in a dose-dependent manner. In conclusion, FUC from Laminaria japonicum ameliorated DZN-induced oxidative stress, pro-inflammatory effects, and injuries to the cardiac, hepatic, and renal tissues. These effects may be related to the antioxidant and anti-inflammatory effects of FUC.
اظهر المزيد [+] اقل [-]A hybrid prediction model for forecasting wind energy resources النص الكامل
2020
Zhang, Yagang | Pan, Guifang
Wind energy is important to the transformation and development of global energy, because it is clean and renewable. However, the productivity of wind power is low due to its volatility, randomness, and uncertainty. Therefore, a new hybrid prediction model based on combined Elman-radial basis function (RBF) and Lorenz disturbance is proposed, which can promote the productivity of wind power by better predicting wind speed, firstly, applying the variational mode decomposition (VMD) algorithm to original nonstationary wind speed data to obtain several relatively stationary intrinsic mode functions (IMF), so as to fully exploit its potential characteristics. Meanwhile, the sample entropy is introduced to determine the decomposition number K. Afterwards, different IMF components with different characteristics are used for training and prediction: Elman neural network with sensitivity to historical state data is used for wind speed trend components; RBF with strong nonlinear mapping capability is adopted for other stochastic modal components. Next, the first-step prediction values can be obtained by reconstructing the predicted results of the respective IMF components. Finally, the Lorenz equation is introduced in view of the effects of atmospheric disturbances on wind fluctuations, which can be used to revise the first-step prediction results to obtain more realistic prediction results. By experimenting with the real data from two different wind farms and comparing with other predictive models, we found that (1) VMD can solve the problem of modal aliasing in empirical mode decomposition, to obtain a better decomposition result; (2) the combined prediction method of Elman and RBF is used for modal components, that is, different algorithms are adopted for different components, which have better prediction effects; (3) in this research, the results of the proposed combination prediction model is more accurate by comparison with the other neural network models. This research work will help the power system to rationally formulate wind farm control strategies, enhance the self-regulation of wind farm, and further promote global energy innovation.
اظهر المزيد [+] اقل [-]Possible role of C60 fullerene in the induction of reproductive toxicity in the freshwater fish, Anabas testudineus (Bloch, 1792) النص الكامل
2020
Sumi, Nechat | Chitra, Kumari Chidambaran
In recent years, the impact of ultrafine nanomaterials on the aquatic organisms and their ecosystems contributed much concern due to their abundance in environment. Several toxicity studies have reported that nanoparticles induced reproductive stress and resulted in reproductive impairment of fishes. The present study was aimed to investigate the stress-induced toxicity of C₆₀ fullerene nanomaterial on various reproductive parameters of the freshwater fish, Anabas testudineus. Fish were exposed to two sublethal concentrations of fullerene C₆₀, one-tenth (5 mg/L) and one-fifth (10 mg/L) of LC₅₀–96 h, for 4, 7, 15, 30, and 60-day durations. At the end of exposure period, the activities of steroidogenic enzymes, 3β-, and 17β-hydroxysteroid dehydrogenase decreased in the testis and ovary thereby indicated that the nanomaterial affected gonadal steroidogenesis. The level of serum testosterone decreased significantly (p < 0.05) in male whereas the level of estradiol showed significant (p < 0.05) reduction in female fish with significant (p < 0.05) increase in the level of serum cortisol in both sexes in concentration- and time-dependent manner. The analysis of the levels of alkali-labile phosphates, plasma calcium, and total protein showed significant (p < 0.05) reduction in female fish without significant changes in male fish, and this could be due to the antiestrogenic action of fullerene C₆₀ nanomaterial. The activity of aromatase enzyme decreased significantly (p < 0.05) in the ovary and brain of female fish, and the decline in the enzyme activity was prominent only in the brain tissue of male fish. The present results suggested that the stress-induced by fullerene C₆₀ exposure provoked reproductive toxicity in the fish, Anabas testudineus.
اظهر المزيد [+] اقل [-]Magnetic nanoparticles for hyperthermia in cancer treatment: an emerging tool النص الكامل
2020
Jose, Jobin | Kumar, Rajesh | Harilal, Seetha | Mathew, Githa Elizabeth | Parambi, Della Grace Thomas | Prabhu, Ankitha | Uddin, Md Sahab | Aleya, Lotfi | Kim, Hun | Mathew, Bijo
Cancer remains as the major cause of death worldwide. The main reason why available therapies fail is that a vicious cycle in established which initiates multiple pathways and recurrence after metastasis. Hyperthermic treatment, which involves heating tumor tissues to a moderate temperature of 40–43 °C, has emerged as an effective strategy for treating tumors. This method is highly efficient at destroying tumor cells and does not induce the side effects of conventional cancer treatments. On the other hand, hyperthermic treatment method can be co-administered with conventional treatments. Nanotechnology had created huge opportunities in almost all areas of research, including the field of hyperthermic treatment. The utilization of magnetic nanoparticles (MNPs) offers functionalities not possible using conventional magnetic materials. In this review, we detail recent developments and applications of MNPs for hyperthermic treatment and discuss future possibilities.
اظهر المزيد [+] اقل [-]Modified heavy metal Pollution index (m-HPI) for surface water Quality in river basins, India النص الكامل
2020
Sahoo, Mrunmayee Manjari | Swain, Janaki Ballav
India is bestowed with huge amount of surface water resources. However, India lacks the quality monitoring of surface water and comprehensive management for sustainable surface water development. A new approach for indexing has been proposed to represent pollution due to heavy metals in surface water. Heavy metal pollution indices (m-HPI) for 60 surface water samples in the peninsular stretch were evaluated during pre-drought, drought and post-drought condition. The Index will be represented by a Positive Index (PI) and a Negative Index (NI), where PI represents the level pollution exceeding the maximum desirable limit and NI reflects the index within the required limit. The PI is assigned as 0 when indicators are present below the detection limit or equal to the maximum required limit. However, the value calculated for NI could be 0 to −1 when the indicators are equal to or less than the suggested maximum desirable limit, and the value could be −1 when the indicators are present below the suggested detection limit. The spatiotemporal variation of water quality pattern was studied by the interpolation maps extracted from ArcGIS. The results are compared with WHO standard to validate the drinking water quality. The calculated indices indicated the suitability of water for domestic and irrigation purposes. The developed indexing system is user friendly, robust, flexible and may evaluate the index considering any water quality standard.
اظهر المزيد [+] اقل [-]Co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions النص الكامل
2020
Li, Jingqiao | Zhang, Wenjing | Qin, Yunqi | Li, Xiaofei | Wu, Shengyu | Chai, Juanfen | Du, Shanghai
To investigate co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions, NH₄⁺ was selected as the target contaminant, and silicon and humic acid (HA) were selected as typical organic and inorganic colloids in groundwater. Column experiments were then conducted to investigate the transport of NH₄⁺ colloids under various hydrochemical conditions. The results showed that because of the different properties of colloidal silicon and HA after combining with NH₄⁺, the co-transport mechanism became significantly different. During transport by the NH₄⁺–colloid system, colloidal silicon occupied the adsorption sites on the medium surface to promote the transport of NH₄⁺, while humic acid (HA) increased the number of adsorption sites of the medium to hinder the transport of NH₄⁺. The co-transport of NH₄⁺ and colloids is closely related to hydrochemical conditions. In the presence of HA, competitive adsorption and morphological changes of HA caused NH₄⁺ to be more likely to be transported at a higher ionic strength (IS = 0.05 m, CaCl₂) and alkalinity (pH = 9.3). In the presence of colloidal silicon, blocking action caused the facilitated transport to be dependent on higher ionic strength and acidity (pH = 4.5), causing the recovery of NH₄⁺ to improve by 7.99%, 222.25% (stage 1), and 8.63%, respectively. Moreover, transport increases with the colloidal silicon concentrations of 20 mg/L then declines at 40 mg/L, demonstrating that increased concentrations will lead to blocking and particle aggregation, resulting in delayed release in the leaching stage. Graphical abstract
اظهر المزيد [+] اقل [-]Synthesis and photocatalytic activity study of S-doped WO3 under visible light irradiation النص الكامل
2020
Chen, Guodong | Wang, Qi | Zhao, Zhilin | Gao, Li | Li, Xiaochen
In this study, a photocatalyst S-doped WO₃ was successfully synthesized by the hydrothermal method. The prepared undoped and S-doped WO₃ samples were then characterized by XRD, SEM, XPS, and UV-vis DRS. The results showed that the band gap energy of S-doped WO₃ was lower than that of the undoped WO₃, which led to a better absorption of visible light. Furthermore, the results of XPS analysis suggested that the doping with S element resulted in an increase in lattice oxygen vacancies on the surface of S-WO₃, which could effectively improve the photocatalytic activity. The photocatalytic performance of the S-WO₃ samples were evaluated by the measurement of methylene blue (MB) degradation under visible light irradiation. The experimental results demonstrated that S-doped WO₃ sample exhibited a much better photodegradation performance compared to undoped WO₃, with the maximum MB removal efficiency of 78.7% for the 5% S-WO₃ sample. Based on the above results, the mechanisms of photodegradation of MB by S-WO₃ were discussed.
اظهر المزيد [+] اقل [-]Biological effects of Avicennia marina (Forssk.) vierh. extracts on physiological, biochemical, and antimicrobial activities against three challenging mosquito vectors and microbial pathogens النص الكامل
2020
Karthi, Sengodan | Vinothkumar, Manohar | Karthic, Uthirarajan | Manigandan, Venkatesan | Saravanan, Ramachandran | Vasantha-Srinivasan, Prabhakaran | Kamaraj, Chinnaperumal | Shivakumar, Muthugounder S. | De Mandal, Surajit | Velusamy, Arumugam | Krutmuang, Patcharin | Senthil-Nathan, Sengottayan
Mosquitoes are principal vector of several vector-borne diseases affecting human beings leading to thousands of deaths per year and responsible for transmitting diseases like malaria, dengue, chikungunya, yellow fever, Zika virus, Japanese encephalitis, and lymphatic filariasis. In the present study, we evaluated the different solvent extracts of mangrove Avicennia marina for their toxicity against larvae of three major mosquito vectors, as well as selected microbial pathogens. The larvicidal mortality of third instars was observed after 24 h. Highest larval mortality was found for the acetone extract of A. marina against Culex quinquefasciatus (LC₅₀ = 0.197 mg/ml; LC₉₀ = 1.5011 mg/ml), Anopheles stephensi (LC₅₀ = 0.176 mg/ml; LC₉₀ = 3.6290 mg/ml), and Aedes aegypti (LC₅₀ = 0.164 mg/ml; LC₉₀ = 4.3554 mg/ml). GC-MS analysis of acetone extract revealed 5 peaks, i.e., 1-hexyl-2-nitrocyclohexane (3.229%), eicosanoic acid (40.582%), cis-9-hexadecenal (70.54%), oleic acid (4.646%), and di-N-decylsulfone (5.136%). Parallel to larvicidal assay, sub-lethal dosage acetone extracts severely affected the enzyme regulations (α,β-carboxylesterase, GST and CYP450) of third instars. Larval and pupal durations increased in all treatment sub-lethal dosage (0.127, 0.151, 0.177, and 0.197 mg/ml), whereas egg hatchability and means of fecundity decreased compared to control. The survival rate was reduced statistically in Cx. quinquefasciatus (χ² = 23.77, df = 1, P = 0.001) in all the treatment dosages as compared to the control. Antimicrobial activity assays showed significant growth inhibition post treatment with acetone and methanol extracts against Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus pneumoniae, Escherichia coli, and Shigella flexneri. Overall, these results indicated the potential employment of A. marina extracts as a source of natural mosquitocidal and antimicrobial compounds of green-based environment.
اظهر المزيد [+] اقل [-]Influence of graphene oxide nanosheets on the cotransport of cu-tetracycline multi-pollutants in saturated porous media النص الكامل
2020
Zhao, Chuanqi | Pei, Shengwei | Ma, Junguan | Song, Zefeng | Xia, Hui | Song, Xiaoming | Qi, Heyang | Yang, Yuesuo
Antibiotic-heavy metal multi-pollutants are produced by intensive livestock farming and become an increasingly prominent problem. In this study, the transport behavior of tetracycline (TC) and its chelate with copper ions (Cu-TC) in saturated sand column with and without graphene oxide (GO) prefilled was investigated by laboratory breakthrough experiments. The effects of pH, ionic strength, and the cotransport with GO were studied detailedly. The results showed that the prepared nano-GO had a single- or multilayered sheet structure with a diameter of several μm. The surface of GO contained abundant oxygen-containing functional groups, which imparted it strong hydrophilicity and electronegativity. Pollutant transport experiments showed that decrease of H⁺ weakened the transport ability of TC and Cu-TC. Both Na⁺ and Ca²⁺ promoted the transport of TC, with Ca²⁺ having a much greater effect. The presence of Na⁺ inhibited the transport of Cu-TC, while Ca²⁺ promoted Cu-TC transport. The addition of Cu²⁺ was more favorable for the transport of Cu-TC than TC alone. In the GO-prefilled column, the effluent concentrations of TC and Cu-TC greatly decreased due to adsorption onto GO surfaces. The transport of Cu-TC was more related to GO concentration than TC alone due to the high affinity between GO and Cu-TC. Moreover, the transport behavior of GO in the sand column was consistent with that of the corresponding TC or Cu-TC, indicating that GO could cotransport with TC and Cu-TC multi-pollutants. Our study showed that the GO would interact with TC and Cu-TC and thus have significant influences on the fate and transport of these pollutions in porous media.
اظهر المزيد [+] اقل [-]Research on measurement and improvement path of industrial green development in China: a perspective of environmental welfare efficiency النص الكامل
2020
Wang Xiping, | Li, Yanmei
The increasing concern about the environmental issue and its serious adverse effects on human health has made China’s industrial green transformation being a matter of public concern. In this study, a network slack-based measure (NSBM) was applied to explore China’s industrial green development level from the perspective of environmental welfare efficiency (EWE), considering not only the impact of industrial development on environment and economy, but also the impact on human well-being. Based on the data of 30 provincial administrative regions in China from 2004 to 2017, the comprehensive efficiency (CE) of China’s industrial sector was measured and decomposed. The results show that the industrial production efficiency (IPE) is much higher than the EWE, and the improvement of the EWE will be the key to realize the green transformation of China’s industry. On this basis, considering the effects of spatial interaction, the spatial Durbin model was established to analyze the driving factors of EWE. Finally, this research puts forward promotion path of industrial green development.
اظهر المزيد [+] اقل [-]