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排序方式: 共有450条查询结果,搜索用时 15 毫秒
101.
Antonio Lozano José Usero Eva Vanderlinden Juan Raez Juan Contreras Benito Navarrete 《Microchemical Journal》2009,93(2):164-172
Air monitoring networks are necessary to assess air quality in order to reduce pollution to levels which minimize harmful effects on human health and the environment. This paper describes a method to design or optimize air quality monitoring networks for nitrogen dioxide and ozone and its application in Malaga, a medium large city located in Andalusia, southern Spain, with traffic being the main source of air pollution. The completion of this method revealed that the old assessment network in Malaga was badly designed and made it possible to determine that one traffic-orientated and one background control station were necessary for NO2 assessment in Malaga, as well as two control stations for O3. First the number of stations necessary is obtained from historical data. Sampling campaigns with passive diffusion samplers at 74 sites were then carried out to obtain information on the pollution distribution in Malaga. The average concentrations found for NO2 and O3 were 22.8 μg/m3 and 64.3 μg/m3 respectively. Maximum values of up to 42.2 μg/m3 NO2 were found in Malaga city centre and O3 reached 91.5 μg/m3 downwind from the emission source. After spatial interpolation of the obtained values with Geographical Information Systems, a selection of the best locations for the monitoring stations was made, in line with the macro- and microscale siting requirements of the European Directive 2008/50/EC on ambient air quality and cleaner air for Europe. 相似文献
102.
Julio Hernndez‐Díaz Angelina Flores‐Parra Rosalinda Contreras 《Heteroatom Chemistry》2004,15(4):307-320
Sixteen different P(III) and P(V) heterocycles derived from 2‐(2‐hydroxyphenyl)‐1H‐benzimidazole ( 1 ) are reported. In these heterocycles the phosphorus atom is part of a six‐membered unsaturated ring. They were mainly studied by multinuclear NMR. The X‐ray diffraction of 3,4‐ benzimidazole‐5,6‐benzo‐2‐dimethylamino‐2‐seleno‐ 1,3,2‐oxazaphosphorinane is reported. Phosphoranes derived from 1 and 3,5‐di‐tert‐butylcatechol, and bearing Cl, NMe2, or phenyl as substituent at phosphorus are presented. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:307–320, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20021 相似文献
103.
Margarita Villar Jos Miguel Urra Sara Artigas-Jernimo Lorena Mazuecos Marinela Contreras Rita Vaz-Rodrigues Francisco J. Rodríguez-del-Río Christian Gortzar Jos de la Fuente 《Molecules (Basel, Switzerland)》2022,27(18)
In the last two years, the coronavirus disease 19 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a scientific and social challenge worldwide. Vaccines have been the most effective intervention for reducing virus transmission and disease severity. However, genetic virus variants are still circulating among vaccinated individuals with different disease symptomatology. Understanding the protective- or disease-associated mechanisms in vaccinated individuals is relevant to advances in vaccine development and implementation. To address this objective, serum-protein profiles were characterized by quantitative proteomics and data-analysis algorithms in four cohorts of uninfected and SARS-CoV-2-infected vaccinated individuals with asymptomatic, non-severe, and severe disease symptomatology. The results show that immunoglobulins were the most overrepresented proteins in infected cohorts when compared to PCR-negative individuals. The immunoglobulin profile varied between different infected cohorts and correlated with protective- or disease-associated capacity. Overrepresented immunoglobulins in PCR-positive individuals correlated with protective response against SARS-CoV-2, other viruses, and thrombosis in asymptomatic cases. In non-severe cases, correlates of protection against SARS-CoV-2 and HBV together with risk of myasthenia gravis and allergy and autoantibodies were observed. Patients with severe symptoms presented risk for allergy, chronic idiopathic thrombocytopenic purpura, and autoantibodies. The analysis of underrepresented immunoglobulins in PCR-positive compared to PCR-negative individuals identified vaccine-induced protective epitopes in various coronavirus proteins, including the spike receptor-binding domain RBD. Non-immunoglobulin proteins were associated with COVID-19 symptoms and biological processes. These results evidence host-associated differences in response to vaccination and the possibility of improving vaccine efficacy against SARS-CoV-2. 相似文献
104.
Orfa Ins Contreras Martínez Alberto Angulo Ortíz Gilmar Santaf Patio 《Molecules (Basel, Switzerland)》2022,27(18)
The growing increase in infections by Candida spp., non-albicans, coupled with expressed drug resistance and high mortality, especially in immunocompromised patients, have made candidemia a great challenge. The efficacy of compounds of plant origin with antifungal potential has recently been reported as an alternative to be used. Our objective was to evaluate the mechanism of the antifungal action of isoespintanol (ISO) against clinical isolates of Candida tropicalis. Microdilution assays revealed fungal growth inhibition, showing minimum inhibitory concentration (MIC) values between 326.6 and 500 µg/mL. The eradication of mature biofilms by ISO was between 20.3 and 25.8% after 1 h of exposure, being in all cases higher than the effect caused by amphotericin B (AFB), with values between 7.2 and 12.4%. Flow cytometry showed changes in the permeability of the plasma membrane, causing loss of intracellular material and osmotic balance; transmission electron microscopy (TEM) confirmed the damage to the integrity of the plasma membrane. Furthermore, ISO induced the production of intracellular reactive oxygen species (iROS). This indicates that the antifungal action of ISO is associated with damage to membrane integrity and the induction of iROS production, causing cell death. 相似文献
105.
Tarek Boudiar Boualem Harfi Maria del Mar Contreras Antonio Segura-Carretero 《Natural product research》2019,33(15):2208-2214
Rosmarinus eriocalyx (rosemary or Elyazir) is an endemic species growing in arid steppe and rocky mountain in the South-West Algeria. This plant is well known in Algeria and Morocco due to its medicinal properties. However, little is known about its phytochemical composition. For this purpose, natural antioxidant compounds from R. eriocalyx were recovered by solid-liquid extraction and characterized by reversed-phase high-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry using negative and positive ionization modes. This analytical methodology enabled the characterization of 101 compounds, which were distributed in five major categories namely hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, flavonoids, phenolic diterpenes and phenolic triterpenes. Moreover, the studied extract generally showed free radical-scavenging and reductive abilities in the range of butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol, and ascorbic acid. Therefore, the result suggests that the aqueous-methanolic extract of R. eriocalyx could serve as a potential source of antioxidants. 相似文献
106.
Abe F Amidei D Apollinari G Ascoli G Atac M Auchincloss P Baden AR Barbaro-Galtieri A Barnes VE Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Bensinger J Beretvas A Berge P Bertolucci S Bhadra S Binkley M Blair R Blocker C Bofill J Booth AW Brandenburg G Brown D Byon A Byrum KL Campbell M Carey R Carithers W Carlsmith D Carroll JT Cashmore R Cervelli F Chadwick K Chapin T Chiarelli G Chinowsky W Cihangir S Cline D Connor D Contreras M Cooper J Cordelli M Curatolo M Day C DelFabbro R 《Physical review letters》1990,64(4):348-352
107.
Yalfani MS Contreras S Medina F Sueiras J 《Chemical communications (Cambridge, England)》2008,(33):3885-3887
Hydrogen peroxide formation is achieved with remarkable productivity at ambient conditions (25 degrees C and atmospheric pressure) in aqueous medium using a heterogeneous catalytic system; formic acid is decomposed in the presence of a continuous flow of O(2) over Pd/gamma-Al(2)O(3) catalyst leading to the generation of hydrogen peroxide; the addition of a negligible amount of bromide ion improves the selectivity of the reaction. 相似文献
108.
Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bacchetta N Bailey MW Bamberger A Barnett BA Barbaro-Galtieri A Barnes VE Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Blair R Blocker C Bolognesi V Booth AW Boswell C Brandenburg G Brown D Buckley-Geer E Budd HS Busetto G Byon-Wagner A Byrum KL Campagnari C Campbell M Carey R Carithers W Carlsmith D Carroll JT Cashmore R Castro A Cervelli F Chadwick K 《Physical review letters》1992,68(10):1458-1462
109.
Hilda R. Morales Martín Pérez-Juárez Laura Cuéllar Lourdes Mendoza Héctor Fernández Rosalinda Contreras 《合成通讯》2013,43(13):1213-1219
A new procedure for the high-yield N-monoalkylation of primary aromatic and aliphatic amines is described. 相似文献
110.
Harmonic and anharmonic symmetry force constants matrices have been calculated using a stepwise coupling method for the twelve isotopic species of nitrosyl fluoride, chloride and bromide. The valence force fields derived from the above matrices were used to recalculate the normal frequencies and the potential energy distribution among force constants. The valence force fields are compared with others previously reported obtained by different methods. 相似文献