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1.
Ruy Exel 《Mathematische Annalen》2002,323(2):259-266
Kirchberg and Wasserman's Theorem, according to which a group is exact if and only if its reduced C*-algebra is exact, is
extended to the context of Fell bundles.
Received: 31 December 2000 / Revised version: 7 August 2001 / Published online: 4 April 2002 相似文献
2.
Phenotypic and Target-Directed Screening Yields New Acaricidal Alternatives for the Control of Ticks
Tatiana Saporiti Mauricio Cabrera Josefina Bentancur María Elisa Ferrari Nallely Cabrera Ruy Prez-Montfort Francisco J. Aguirre-Crespo Jorge Gil Ulises Cuore Dimitris Matiadis Marina Sagnou Guzmn Alvarez 《Molecules (Basel, Switzerland)》2022,27(24)
Rhipicephalus microplus, the “common cattle tick”, is the most important ectoparasite in livestock worldwide due to the economic and health losses it produces. This tick is a vector for pathogens of several tick-borne diseases. In Latin American countries, damages reach approximately USD 500 million annually due to tick infections, as well as tick-borne diseases. Currently, resistant populations for every chemical group of acaricides have been reported, posing a serious problem for tick control. This study aims to find new alternatives for controlling resistant ticks with compounds derived from small synthetic organic molecules and natural origins. Using BME26 embryonic cells, we performed phenotypic screening of 44 natural extracts from 10 Mexican plants used in traditional medicine, and 33 compounds selected from our chemical collection. We found 10 extracts and 13 compounds that inhibited cell growth by 50% at 50 µg/mL and 100 µM, respectively; the dose-response profile of two of them was characterized, and these compounds were assayed in vitro against different life stages of Rhipicephalus microplus. We also performed a target-directed screening of the activity of triosephosphate isomerase, using 86 compounds selected from our chemical collection. In this collection, we found the most potent and selective inhibitor of tick triosephosphate isomerase reported until now. Two other compounds had a potent acaricidal effect in vitro using adults and larvae when compared with other acaricides such as ivermectin and Amitraz. Those compounds were also selective to the ticks compared with the cytotoxicity in mammalian cells like macrophages or bovine spermatozoids. They also had a good toxicological profile, resulting in promising acaricidal compounds for tick control in cattle raising. 相似文献
3.
4.
Textile/Metal–Organic‐Framework Composites as Self‐Detoxifying Filters for Chemical‐Warfare Agents 下载免费PDF全文
Elena López‐Maya Dr. Carmen Montoro Dr. L. Marleny Rodríguez‐Albelo Dr. Salvador D. Aznar Cervantes Dr. A. Abel Lozano‐Pérez Prof. José Luis Cenís Dr. Elisa Barea Prof. Jorge A. R. Navarro 《Angewandte Chemie (International ed. in English)》2015,54(23):6790-6794
The current technology of air‐filtration materials for protection against highly toxic chemicals, that is, chemical‐warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self‐cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal–organic framework (MOF) materials to develop advanced self‐detoxifying adsorbents of chemical‐warfare agents containing hydrolysable P? F, P? O, and C? Cl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air‐permeation properties of the textiles with the self‐detoxifying properties of the MOF material. 相似文献
5.
Vanézia L. Silva Ruy Carvalho Matheus P. Freitas Cláudio F. Tormena Walclée C. Melo 《Structural chemistry》2007,18(5):605-609
Spectrometric and theoretical tools have been employed in this study in order to elucidate the structures of DTPA (diethylenetriaminepentaacetic
acid) complexed to copper and lead. Mass spectrometry allowed determining the 1:1 stoichiometry of metal:ligand, while infrared
spectroscopy demonstrated that both N and O are sites for complexation. 13C NMR analysis showed the existence of free and complexed carboxyl groups, due to a straight singlet at 180.7 ppm (free carboxylic
13C) and to a broad signal at 179.3 ppm (complexed carboxylic 13C, 2
J
Pb…O=C). A distorted NMR signal were observed for the Cu–DTPA carboxyl group, due to the Cu2+ paramagnetism. Based on the spectrometric evidences for the metal–DTPA structures, DFT optimizations were carried out and
an octahedral-like arrangement for the Cu complex and a “shell-like” arrangement for the Pb complex, both hexa-coordinated,
were then proposed for the structures of the titled compounds.
相似文献
Ruy CarvalhoEmail: |
6.
Ultra‐high pressure LC for astaxanthin determination in shrimp by‐products and active food packaging
A. Sanches‐Silva T. Ribeiro T. G. Albuquerque P. Paseiro R. Sendón A. Bernaldo de Quirós J. López‐Cervantes D. I. Sánchez‐Machado H. Soto Valdez I. Angulo G. P. Aurrekoetxea H. S. Costa 《Biomedical chromatography : BMC》2013,27(6):757-764
Nowadays, there is increasing interest in natural antioxidants from food by‐products. Astaxanthin is a potent antioxidant and one of the major carotenoids in crustaceans and salmonids. An ultra‐high pressure liquid chromatographic method was developed and validated for the determination of astaxanthin in shrimp by‐products, and its migration from new packaging materials to food simulants was also studied. The method uses an UPLC® BEH guard‐column (2.1 × 5 mm, 1.7 µm particle size) and an UPLC® BEH analytical column (2.1 × 50 mm, 1.7 µm particle size). Chromatographic separation was achieved using a programmed gradient mobile phase consisting of (A) acetonitrile–methanol (containing 0.05 m ammonium acetate)–dichloromethane (75:20:5, v/v/v) and (B) ultrapure water. This method was evaluated with respect to validation parameters such as linearity, precision, limit of detection, limit of quantification and recovery. Low‐density polyethylene films were prepared with different amounts of the lipid fraction of fermented shrimp waste by extrusion, and migration was evaluated into food simulants (isooctane and ethanol 95%, v/v). Migration was not detected under the tested conditions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
7.
Ingrid Hauser Ana B. Colaço Julie A. Skjæran Aslak Einbu Kjetill Østgaard Hallvard F. Svendsen Francisco J. Cervantes 《Applied biochemistry and biotechnology》2013,169(4):1449-1458
Large-scale amine-based CO2 capture will generate waste containing large amounts of ammonia, in addition to contaminants such as the actual amine as well as degradation products thereof. Monoethanolamine (MEA) has been a dominant amine applied so far in this context. This study reveals how biological N removal can be achieved even in systems heavily contaminated by MEA in post- as well as pre-denitrification treatment systems, elucidating the rate-limiting factors of nitrification as well as aerobic and denitrifying biodegradation of MEA. The hydrolysis of MEA to ammonia readily occurred both in post- and pre-denitrification treatment systems with a hydraulic retention time of 7 h. MEA removal was ≥99?±?1 % and total nitrogen removal 77?±?10 % in both treatment systems. This study clearly demonstrates the advantage of pre-denitrification over post-denitrification for achieving biological nitrogen removal from MEA-contaminated effluents. Besides the removal of MEA, the removal efficiency of total nitrogen as well as organic matter was high without additional carbon source supplied. 相似文献
8.
Oscar Cervantes Zaira del Rocio Lopez Norberto Casillas Peter Knauth Nayeli Checa Francisco Apolinar Cholico Rodolfo Hernandez-Gutirrez Luis Hector Quintero Jose Avila Paz Mario Eduardo Cano 《Molecules (Basel, Switzerland)》2022,27(2)
A ferrofluid with 1,2-Benzenediol-coated iron oxide nanoparticles was synthesized and physicochemically analyzed. This colloidal system was prepared following the typical co-precipitation method, and superparamagnetic nanoparticles of 13.5 nm average diameter, 34 emu/g of magnetic saturation, and 285 K of blocking temperature were obtained. Additionally, the zeta potential showed a suitable colloidal stability for cancer therapy assays and the magneto-calorimetric trails determined a high power absorption density. In addition, the oxidative capability of the ferrofluid was corroborated by performing the Fenton reaction with methylene blue (MB) dissolved in water, where the ferrofluid was suitable for producing reactive oxygen species (ROS), and surprisingly a strong degradation of MB was also observed when it was combined with H2O2. The intracellular ROS production was qualitatively corroborated using the HT-29 human cell line, by detecting the fluorescent rise induced in 2,7-dichlorofluorescein diacetate. In other experiments, cell metabolic activity was measured, and no toxicity was observed, even with concentrations of up to 4 mg/mL of magnetic nanoparticles (MNPs). When the cells were treated with magnetic hyperthermia, 80% of cells were dead at 43 °C using 3 mg/mL of MNPs and applying a magnetic field of 530 kHz with 20 kA/m amplitude. 相似文献
9.
We realize Kellendonk’s C*-algebra of an aperiodic tiling as the tight C*-algebra of the inverse semigroup associated to the
tiling, thus providing further evidence that the tight C*-algebra is a good candidate to be the natural associative algebra
to go along with an inverse semigroup. 相似文献
10.
A key requirement in the recent development of highly efficient silicon solar cells is the outstanding passivation of their surfaces. In this work, plasma enhanced chemical vapour deposition of a triple layer dielectric consisting of amorphous silicon, silicon oxide and silicon nitride, charged extrinsically using corona, has been used to demonstrate extremely low surface recombination. Assuming Richter's parametrisation for bulk lifetime, an effective surface recombination velocity Seff = 0.1 cm/s at Δn = 1015 cm–3 has been obtained for planar, float zone, n ‐type, 1 Ω cm silicon. This equates to a saturation current density J0s = 0.3 fA/cm2, and a 1‐sun implied open‐circuit voltage of 738 mV. These surface recombination parameters are among the lowest reported for 1 Ω cm c‐Si. A combination of impedance spectroscopy and corona‐lifetime measurements shows that the outstanding chemical passivation is due to the small hole capture cross section for states at the interface between the Si and a‐Si layer which are hydrogenated during nitride deposition. (© 2016 The Authors. Phys. Status Solidi RRL published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献