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النتائج 5601 - 5610 من 6,489
Does the SO2 emissions trading scheme encourage green total factor productivity? An empirical assessment on China’s cities النص الكامل
2020
Hou, Bingqing | Wang, Bing | Du, Minzhe | Zhang, Ning
As a market-based environmental regulation tool, emissions trading scheme for SO₂ (SO₂ ETS) has been carried out in China for decades, so impacts of SO₂ ETS have become a vital issue to the society. Based on the SO₂ ETS of China in 2007, this paper attempts to test and verify impacts of the scheme on environment and economy, especially on green total factor productivity (TFP). We firstly combine biennial weight-modified non-radial direction distance function and Luenberger productivity indicator to measure and decompose the green TFP of 280 cities in China over the period 2003 to 2016, and apply a difference-in-differences method (DID) with fixed effect models to investigate whether SO₂ ETS achieves a win–win scenario of “emission reducing” and “efficiency increasing.” The results show that the scheme significantly may decrease SO₂ emissions and SO₂ intensity by 12.3% and 11.0%, respectively, in ETS regions while no obvious impact on GDP. In terms of green TFP, we find SO₂ ETS inhibits the growth of green TFP, and the negative impact mainly caused by the deterioration in efficiency change. Therefore, we hold that SO₂ ETS is effective for improving environment, but it is still difficult to achieve the promotion of green TFP simultaneously.
اظهر المزيد [+] اقل [-]Does the ubiquitous use of essential oil-based products promote indoor air quality? A critical literature review النص الكامل
2020
Angulo Milhem, Shadia | Verriele, Marie | Nicolas, Melanie | Thévenet, Frédéric
Essential oils are frequently used as natural fragrances in housecleaning products and air fresheners marketed as green and healthy. However, these substances are volatile and reactive chemical species. This review focuses on the impact of essential oil-based household products on indoor air quality. First, housecleaning products containing essential oils are explored in terms of composition and existing regulations. Specific insight is provided regarding terpenes in fragranced housecleaning products, air fresheners, and pure essential oils. Second, experimental methodologies for terpene monitoring, from sampling to experimental chambers and analytical methods, are addressed, emphasizing the experimental issues in monitoring terpenes in indoor air. Third, the temporal dynamics of terpene emissions reported in the literature are discussed. Despite experimental discrepancies, essential oil-based products are significant sources of terpenes in indoor air, inducing a high exposure of occupants to terpenes. Finally, the fate of terpenes is explored from sorptive and reactive points of view. In addition to terpene deposition on surfaces, indoor oxidants may induce homogeneous and heterogeneous reactions, resulting in secondary pollutants, such as formaldehyde and secondary organic aerosols. Overall, essential oil-based products can negatively impact indoor air quality; therefore, standard protocols and real-scale approaches are needed to explore the indoor physics and chemistry of terpenes, from emissions to reactivity.
اظهر المزيد [+] اقل [-]Changes in extrapulmonary organs and serum enzyme biomarkers after chronic exposure to Buenos Aires air pollution النص الكامل
2020
Maglione, Guillermo Alberto | Kurtz, Melisa Lidia | Orona, Nadia Soledad | Astort, Francisco | Brites, Fernando | Morales, Celina | Berra, Alejandro | Tasat, Deborah Ruth
Urban air pollution is a serious environmental problem in developing countries worldwide, and health is a pressing issue in the megacities in Latin America. Buenos Aires is a megacity with an estimated moderate Air Quality Index ranging from 42 to 74 μg/m³. Exposure to Urban Air Particles from Buenos Aires (UAP-BA) induces morphological and physiological respiratory alterations; nevertheless, no studies on extrapulmonary organs have been performed. The aim of the present study was to explore the health effects of chronic exposure to UAP-BA (1, 6, 9, and 12 months) on the liver, heart, and serum risk biomarkers. BALB/c mice were exposed to UAP-BA or filtered air (FA) in inhalation chambers, and liver and heart histopathology, oxidative metabolism (superoxide dismutase, SOD; catalase, CAT; lipoperoxidation, TBARS), amino transaminases (AST, ALT) as serum risk biomarkers, alkaline phosphatase (ALP), paraxonase-1 (PON-1), and lipoprotein-associated phospholipase A2 (Lp-PLA2) were evaluated. Chronic exposure to real levels of UAP in Buenos Aires led to alterations in extrapulmonary organs associated with inflammation and oxidative imbalance and to changes in liver and heart risk biomarkers. Our results may reflect the impact of the persistent air pollution in Buenos Aires on individuals living in this Latin American megacity.
اظهر المزيد [+] اقل [-]Nanoparticles and its biomedical applications in health and diseases: special focus on drug delivery النص الكامل
2020
Zahin, Nuzhat | Anwar, Raihanatul | Tewari, Devesh | Kabir, Md Tanvir | Sajid, Amin | Mathew, Bijo | Uddin, Md Sahab | Aleya, Lotfi | Abdel-Daim, Mohamed M.
Nanotechnology is an emerging technology that deals with nanosized particles possessing crucial research roles and application. Disciplines like chemistry, biology, physics, engineering, materials science, and health sciences provide an accumulated knowledge of nanotechnology. Nonetheless, it has vast submissions precisely in biology, electronics, and medicine. Aimed at drug delivery system, nanoparticles are based on the mechanism of entrapment of the drugs or biomolecules into the interior structure of the particles; another mechanism could be that the drugs or the biomolecules can be absorbed onto the exterior surfaces of the particles. Currently, nanoparticles (NPs) are used in the delivery of drugs, proteins, genes, vaccines, polypeptides, nucleic acids, etc. In recent years, various applications of the drug delivery system via NPs have encountered an enormous position sector like pharmaceutical, medical, biological, and others. Considering the impact of NPs in drug delivery systems, this review focuses on the detailed profile of NPs, its impact on biology and medicine, and their commercialization prospects.
اظهر المزيد [+] اقل [-]Determination of trace elements in Sergio mirim: an evaluation of sample preparation methods and detection techniques النص الكامل
2020
Mandlate, Jaime S. | Soares, Bruno M. | Andrade, Carlos F. F. | Colling, Leonir A. | Primel, Ednei G. | Mesko, Marcia F. | Duarte, Fabio A.
In this work, some trace elements (As, Cd, Cr, Cu, and Pb) were determined for the first time in the crustacean Sergio mirim (Decapoda: Thalassinidea: Callianassidae) from Southern Coast (Rio Grande, RS) of Brazil. The trace element determination was carried out by graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different microwave radiation-based sample digestion methods were evaluated. The analyte concentration ranged from 1.45 to 3.70 μg g⁻¹ for As, 0.615 to 0.942 μg g⁻¹ for Cd, 0.884 to 7.20 μg g⁻¹ for Cr, 122 to 275 μg g⁻¹ for Cu, and 0.390 to 0.916 μg g⁻¹ for Pb. The limits of quantification for As, Cd, Cr, Cu, and Pb were 0.12, 0.01, 0.16, 0.92, and 0.06 μg g⁻¹, respectively. The accuracy was evaluated by results comparison between GF AAS and ICP-MS techniques, as well as by analysis of certified reference materials of fish muscle and oyster tissue, with agreement from 92 to 108%. The feasibility of using Sergio mirim as a promising environmental bioindicator candidate was evaluated, since that it is an abundant organism in the studied area (South cost of Brazil) as well as in other places around the world.
اظهر المزيد [+] اقل [-]Mechanism study of enhanced interaction between gaseous elemental mercury and hydroxylated UIO-66 النص الكامل
2020
Zhou, Changsong | Zhu, Wenxin | Chang, Xiong | Ding, Ding | Zhang, Tingting | Chen, Jiamin | Wu, Hao | Yang, Hongmin | Sun, Lushi
Novel hydroxylated UIO-66 for gaseous elemental mercury (Hg⁰) removal has been considered to be an emerging method because of its economical and reusable property. Density functional theory studies were investigated to reveal the enhanced heterogeneous interaction mechanisms between mercury and hydroxylated UIO-66 with and without the presence of H₂O₂ vapor. The adsorption and dissociation of H₂O₂ and the generation mechanism of surface hydroxyls on UIO-66 were investigated. Results indicated that H₂O₂ preferred to disconnect the O–O bond followed by the generation of two hydroxyls in the presence of H₂O₂. The hydroxyl adsorbed on UIO-66 and formed the UIO-66 hydroxylation product. The interaction performances between Hg⁰, H₂O₂, and UIO-66 as well as the interaction performances between Hg⁰ and hydroxylated UIO-66 systems were both evaluated through binding energy and the Mulliken charge analysis. Interacted energies indicated thermodynamically favorable processes of Hg–OH formation on hydroxylated UIO-66. The Mulliken charge changes revealed an oxidative process of mercury.
اظهر المزيد [+] اقل [-]Learning soft sensors using time difference–based multi-kernel relevance vector machine with applications for quality-relevant monitoring in wastewater treatment النص الكامل
2020
Wu, Jing | Cheng, Hongchao | Liu, Yiqi | Huang, Daoping | Yuan, Longhua | Yao, Lingying
Considering the time-varying, uncertain and non-linear properties of the wastewater treatment process (WWTPs), a novel multi-kernel relevance vector machine (MRVM) soft sensor based on time difference (TD) is proposed to predict the quality-relevant but difficult-to-measure variable. Firstly, a novel dimension reduction technique is introduced to reduce data dimension and model complexity. Secondly, the parameters of the kernel model are optimized by the intelligent optimization algorithm (PSO). Besides, the TD strategy is introduced to enhance the robustness of MRVM when exposing to dynamic environments. Finally, the proposed model was assessed through two simulation studies and a real WWTP with the results demonstrating the effectiveness of the proposed model. Graphical abstract Framework of Lasso-TD-MRVM soft sensor model
اظهر المزيد [+] اقل [-]Characterization of cannonball jellyfish (Stomolophus sp. 2) blue protein: a pH-stable pigment النص الكامل
2020
Martínez-Pérez, Raúl Balam | Díaz-Tenorio, Lourdes Mariana | Leyva Soto, Luis Alonso | Gortáres-Moroyoqui, Pablo | García-Rico, Leticia | Rodríguez, Jorge Alberto
Pigments are present in a broad variety of terrestrial and aquatic organisms. The cannonball jellyfish (Stomolophus sp. 2) is an important fishery resource in the northwest of Mexico and is processed to be traded and consumed as seafood. During the process, water with a soluble blue pigment and other compounds are discarded to the environment. In this work, we present some properties of the blue pigment from Stomolophus sp.2 (S2bp), to decide if it could be considered as a potential value-added waste and avoid the blue proteinaceous pigment wastewater. S2bp was purified to homogeneity and had a molecular mass of 28.0 kDa; this protein exhibited a ʎₘₐₓ at 650 nm, contained Zn²⁺ and Cu²⁺ metal ions, and was stable from 10 to 50 °C and in a pH range of 3.0 to 13.0 for 1 h. It had halotolerant characteristics maintaining the blue coloration in a broad range of ionic strength (0–4 M NaCl) and showed changes in ʎₘₐₓ with chaotropic salts. In addition, S2bp was stable in the presence of organic acids and EDTA and in zwitterionic, anionic, and nonionic detergents at critical micellar concentration. However, oxidant reagents like NaClO and H₂O₂ decrease the coloration. These results show that the jellyfish pigment is a stable protein which makes it an alternative pigment for the food industry.
اظهر المزيد [+] اقل [-]Iron and molybdenum mixed oxide supported on Al-PILC for the catalytic oxidative desulfurization of dibenzothiophene in simulated diesel fuel النص الكامل
2020
Tireli, Aline Auxiliadora | do Rosário Guimarães, Iara | Mello Mattos de Castro, Guilherme | Gonçalves, Mateus Aquino | de Castro Ramalho, Teodorico | Guerreiro, Mário Cesar
In this work, three novel catalysts were prepared by 2.5, 5.0, and 10.0 wt.% facile impregnation with an iron and molybdenum mixed oxide (Fe/Mo) on an aluminum pillared clay (Al-PILC) support. These materials were characterized by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), temperature programed reduction (TPR), and nitrogen (N₂) physisorption at 77 K. Characterizations indicated that the metal particles were dispersed on the surface of the three catalysts, and the interlayer d₀₀₁ spacing of the pillared material remained unchanged after the impregnation process. The catalytic tests showed good results for DBT oxidation using the synthesized catalysts, with high turnover frequency (TOF) values, particularly for the material with 5.0 wt.% Fe/Mo. Theoretical calculations were carried out at the density functional theory (DFT) level, to investigate how the DBT molecules were adsorbed onto the surface of the mixed oxide. The lowest energy proposal was obtained when both Fe and Mo were present at the active sites, indicating a possible synergistic effect of the metals on catalyst activity. Reuse tests indicated that the catalysts could be employed effectively for up to 3 cycles in a row, then a decrease in activity occurred and the active sites needed to be regenerated.
اظهر المزيد [+] اقل [-]When male seahorses take the female contraceptive pill النص الكامل
2020
D’Alvise, Nathalie Prévot | Richard, Simone | Aublanc, Philippe | Bunet, Robert | Bonnefont, Jean-Luc
17α-ethinylestradiol (EE2), the female contraceptive pill, has been detected in mediterranean coasts where seahorse populations, Hippocampus guttulatus, live. Low environmental concentrations have the potential to disrupt growth but also endocrine metabolism, and this imbalance is all the more critical in early life stage. To investigate the impact of EE2 in reared seahorses, we exposed aged 2 months and sexually undifferentiated seahorses to an environmental concentration of 21 ng/L of EE2 for a period of 30 days. EE2 exposure led to a 19% reduction in weight, but also a mortality rate of 27%. This exposure predicted demasculinization of male individuals with a late onset of secondary sexual characteristics. EE2 exposure led to an increase of the free androgen index, but significant reductions of estradiol and testosterone in males were observed. This low estrogen concentration seemed to impact the positive feedback on luteinizing hormone (LH) with a decrease in LH production. Added to this, synthetic estrogen had a negative impact on the production and the release of follicle-stimulating hormone. Contrary to all expectations, females demonstrated a significant decrease in vitellogenin, following exposure to EE2 at 21 ng/L, while no changes were detected in males. This first study on the European long-snouted seahorses confirmed the deleterious impact of the female contraceptive pill with a real impact on growth, sexual differentiation, and maturation in young immature seahorses.
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