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61.
S. Renault M. Baudrimont N. Mesmer-Dudons P. Gonzalez S. Mornet A. Brisson 《Gold bulletin》2008,41(2):116-126
For years, nanotechnologies have developed the use of common materials, such as iron or silica, at an extremely small scale
because of their new properties (reactivity, conductivity, optical sensitivity). More precisely, gold nanoparticles are used
in numerous technologies such as electronics, new paints or research on cancer. But, despite their promising future and expansive
utilization, only a few studies deal with their behaviors or impacts on the environment. Thus, we decided to explore the impacts
of amine-coated 10nm gold nanoparticle (AuNp) contaminations on two freshwater aquatic models. The green algaScenedesmus subspicatus was submitted to 24 h-direct exposures at four AuNp concentrations (1.6×102, 1.6×103, 1.6×104 and 1.6×105 AuNp/cell) along with a control condition. The process used for the freshwater bivalvesCorbicula fluminea was a trophic exposure during 7 days to three AuNp concentrations (1.6×103, 1.6×104 and 1.6×105 AuNp/cell). These conditions were tested in triplicate with controls. For these experiments, OD measurements (γ= 520nm) were
performed to verify AuNp concentrations in the water (stability). Cell numerations of algae were used to determine the growth/mortality
effects on this species. Cellular impacts and AuNp distributions in the two species were revealed by transmission electron
microscopy (TEM). The bioaccumulation rates were assessed by gold dosagesvia MS-ICP procedures. Molecular impacts were analyzed by quantifications of metallothionein concentrations (metal detoxification
protein) and genetic expressions via real-time RT-PCR. Our study focused on the expression of six genes encoding proteins
involved in: metal detoxification (metallothionein), the response to oxidative stress (catalase and superoxide-dismutase),
the mitochondrial respiratory chain (subunit 1 of the cytochrome-C-oxidase), the concentration of mitochondria (RNA12s) and
the response to xenobiotics (glutathione S transferase); using the β-actin as reference of the basal rates of gene expressions. 相似文献
62.
Pavel Solopov Ruben Manuel Luciano Colunga Biancatelli Christiana Dimitropoulou John D. Catravas 《International journal of molecular sciences》2021,22(11)
We developed two models of chemically induced chronic lung injury and pulmonary fibrosis in mice (intratracheally administered hydrochloric acid (HCl) and intratracheally administered nitrogen mustard (NM)) and investigated male–female differences. Female mice exhibited higher 30-day survival and less weight loss than male mice. Thirty days after the instillation of either HCl or NM, bronchoalveolar lavage fluid displayed a persistent, mild inflammatory response, but with higher white blood cell numbers and total protein content in males vs. females. Furthermore, females exhibited less collagen deposition, milder pulmonary fibrosis, and lower Ashcroft scores. After instillation of either HCl or NM, all animals displayed increased values of phosphorylated (activated) Heat Shock Protein 90, which plays a crucial role in the alveolar wound-healing processes; however, females presented lower activation of both transforming growth factor-β (TGF-β) signaling pathways: ERK and SMAD. We propose that female mice are protected from chronic complications of a single exposure to either HCl or NM through a lesser activation of TGF-β and downstream signaling. The understanding of the molecular mechanisms that confer a protective effect in females could help develop new, gender-specific therapeutics for IPF. 相似文献
63.
Unique Crystal Structure of a Novel Surfactant Protein from the Foam Nest of the Frog Leptodactylus vastus 下载免费PDF全文
Dr. Denise Cavalcante Hissa Dr. Gustavo Arruda Bezerra Dr. Ruth Birner‐Gruenberger Dr. Luciano Paulino Silva Dr. Isabel Usón Prof. Dr. Karl Gruber Prof. Dr. Vânia Maria Maciel Melo 《Chembiochem : a European journal of chemical biology》2014,15(3):393-398
Breeding by releasing eggs into stable biofoams (“foam nests”) is a peculiar reproduction mode within anurans, fish, and tunicates; not much is known regarding the biochemistry or molecular mechanisms involved. Lv‐ranaspumin (Lv‐RSN‐1) is the predominant protein from the foam nest of the frog Leptodactylus vastus. This protein shows natural surfactant activity, which is assumed to be crucial for stabilizing foam nests. We elucidated the amino acid sequence of Lv‐RSN‐1 by de novo sequencing with mass‐spectrometry and determined the high‐resolution X‐ray structure of the protein. It has a unique fold mainly composed of a bundle of 11 α‐helices and two small antiparallel β‐strands. Lv‐RSN‐1 has a surface rich in hydrophilic residues and a lipophilic cavity in the region of the antiparallel β‐sheet. It possesses intrinsic surface‐active properties, reducing the surface tension of water from 73 to 61 mN m?1 (15 μg mL?1). Lv‐RSN‐1 belongs to a new class of surfactants proteins for which little has been reported regarding structure or function. 相似文献
64.
Angélica R. Jiménez‐Sánchez Israel Santillán Juvenal Rodriguez Resendiz Carlos A. Gonzalez‐Gutierrez Jorge D. Mendiola‐Santibañez 《International journal of imaging systems and technology》2012,22(2):137-144
In this article, a morphological contrast index based on the Weber's law is proposed to quantify the contrast in a processed image. This measure involves the contours of the image along with its background. The proposal made here is applied to detect the image with higher contrast, and also identify the enhanced image most similar to the original. Moreover, the contrast index is compared with other four indexes reported in the current literature. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 137–144, 2012 相似文献
65.
The aim of this paper is to review some of the parameters influencing the corrosivity of alkanolamine solvents used for natural gas purification or for CO2 capture. In the light of literature data and of new experimental results, the influences of temperature and of acid gas loading are discussed. These two parameters appear to have a strong impact on corrosion rates of carbon steel, with extrapolated corrosion rates of several tens of mm/year for the highest temperature and acid gas loading condition. It is then proposed to discuss about similarities and differences between natural gas processing and CO2 capture from flue gas. For both applications, alkanolamine processes are used. Still, differences can be found in operating parameters. The most significant gap concerns the lean amine sections. In acid gas treatment, the regeneration of the solvent is often performed down to zero loading. Under these conditions, an extremely low corrosivity of the lean solvent is expected. On the contrary, CO2 capture from flue gas requires only a partial stripping of the CO2 in the regeneration section, due to energy efficiency reasons. Then, the lean solvent still contains some acid gas, and subsequently a higher corrosivity. Finally, the general principles for material selection for the different parts of acid gas removal units are discussed, considering both cases of natural gas processing or CO2 capture. 相似文献
66.
67.
M.A. Heckman K. Sherry E. Gonzalez De Mejia 《Comprehensive Reviews in Food Science and Food Safety》2010,9(3):303-317
ABSTRACT: The consumption of energy drinks is rapidly increasing, as demonstrated by their large market growth. The targeted demographic group is teenagers, young adults, 18 to 34 y old; although expansion into nontraditional markets is also occurring. It is claimed that energy drinks can offer an increased energy boost related to their ingredient profile of caffeine, taurine, herbal extracts, and vitamins. Research suggests that energy drink formulations, in addition to increasing energy utilization, may also improve mood, enhance physical endurance, reduce mental fatigue, and increase reaction time. However, in most cases, the corresponding mechanisms of action are not clear. In addition, concerns have been raised over their safety and with a currently weak regulatory environment, efforts need to be made to ensure consumer safety. The objective of this article is to review the current U.S. energy drink market with emphasis on its market size, target demographic, active ingredients, potential benefits, safety, and regulations. 相似文献
68.
69.
Luciano Cardellicchio 《Building Research & Information》2013,41(2):160-179
ABSTRACTThe Jubilee Church in the south-eastern outskirts of Rome is one of the first buildings constructed with super white reinforced concrete with self-cleaning photocatalytic cement. However, 16 years after the opening of the building, the self-cleaning and colour-preserving properties arising from the titania particles (TiO2) within the concrete mix are not meeting the design requirements and the concrete is showing premature evidence of decay. While the form of the decay is affecting the appearance of the building and not its structural soundness, the ageing pattern of the building's components is resulting in a high maintenance cost, one not easily affordable within the ordinary budget supported by a small parish. This study comprises the first comprehensive step in understanding the causes of the accelerated ageing pattern of the concrete, highlighting methods to improve the long-term durability of the concrete and therefore reduce the cost of its maintenance. Moreover, this research offered the opportunity to test the durability and the effectiveness of the TiO2 in the real conditions on an actual building featuring non-standard geometries. The findings highlight how the ageing pattern directly connects with the geometry of the building and inadequate consideration of the local weathering at the design stage. 相似文献