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Antibacterial activity of five Peruvian medicinal plants against Pseudomonas aeruginosa

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Asian Pacific Journal of Tropical Biomedicine 2015年第11期5卷 928-931页

作者： Gabriela Ulloa-Urizar miguel angel Aguilar-Luis María del Carmen De Lama-Odría José Camarena-Lizarzaburu Juana del Valle Mendoza Centro de Investigacin de la Facultad de Ciencias de la Salud Universidad Peruana de Ciencias Aplicadas-UPC Facultad de Ciencias Biolgicas Universidad Nacional Mayor de San Marcos (UNMSM) Instituto de Investigacin Nutricional

Objective: To evaluate the susceptibility of Pseudomonas aeruginosa(P. aeruginosa)in vitro to the ethanolic extracts obtained from five different Peruvian medicinal ***: The plants were chopped and soaked in absolute ethanol(1:2, w/v). The antibacterial activity of compounds against P. aeruginosa was evaluated using the cupplate agar diffusion ***: The extracts from Maytenus macrocarpa("Chuchuhuasi"), Dracontium loretense Krause("Jergon Sacha"), Tabebuia impetiginosa("Tahuari"), Eucalyptus camaldulensis Dehn(eucalyptus), Uncaria tomentosa("U?a de gato") exhibited favorable antibacterial activity against P. aeruginosa. The inhibitory effect of the extracts on the strains of P. aeruginosa tested demonstrated that Tabebuia impetiginosa and Maytenus macrocarpa possess higher antibacterial ***: The results of the present study scientifically validate the inhibitory capacity of the five medicinal plants attributed by their common use in folk medicine and contribute towards the development of new treatment options based on natural products.

关键词： Pseudomonas Medicinal plants Maytenus macrocarpa D

Local characterization of the polarization state of 3D electromagnetic fields:an alternative approach

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Photonics Research 2023年第7期11卷 1326-1338页

作者： ROSARIO MARTíNEZ-HERRERO DAVID MALUENDA marcos AVINOA ARTUR CARNICER IGNASI JUVELLS angel S.SANZ Departamento de Óptica Universidad Complutense de Madrid(UCM)Ciudad Universitaria28040 MadridSpain Facultat de Física Departament de Física aplicadaUniversitat de Barcelona(UB)Martíi Franquès 108028 BarcelonaSpain

A precise knowledge of the polarization state of light is crucial in technologies that involve the generation and application of structured light fields. The implementation of efficient methods to determine and characterize polarization states is mandatory;more importantly, these structured light fields must be at any spatial location at a low expense. Here, we introduce a new characterization method that relies on a rather convenient description of electric fields without neglecting their 3D nature. This method is particularly suitable for highly focused fields,which exhibit important polarization contributions along their propagation direction in the neighborhood of the focal region;i.e., the contributions out of the planes transverse to the optical axis, conventionally used to specify the polarization state of these fields. As shown, the method allows the extraction of information about the three field components at relatively low computational and experimental costs. Furthermore, it also allows characterization of the polarization state of a field in a rather simple manner. To check the feasibility and reliability of the method, we determined both analytically and experimentally the local polarization states for a series of benchmark input fields with it, finding excellent agreement between the theory and experiment.

关键词： polarization characterization state

Toughening of Immiscible rPS/SAN Blends by SEBS Elastomers: Properties and Morphology

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Journal of Materials Science and Chemical Engineering 2022年第3期10卷 42-62页

作者： Khaled Bedjaoui Rodrigo Navarro Rachida Krache Juan Lopez Valentin Rebeca Herrero Calderon Alberto Fernandez Torres angel marcos Fernandez Laboratory Multiphas Polymeric Materials (LMPMP) Faculty of Technology University Ferhat Abbas Setif-1 Setif Algerie Instituto de Ciencia y Tecnologia de Polimeros (CSIC) Department of Fisica de Polimeros Elastomeros y Aplicaciones Energeticas Madrid Spain

In this research, an attempt was made to improve compatibility in a polymer blend composed of incompatible constituents, namely, recycled polystyrene (rPS) and polystyrene-co-acrylonitrile (SAN), through the addition of a compatibilizer. The compatibilizing agent, styrene-ethylenebutadiene-styrene block copolymer (SEBS), was added to the polymer blend in ratios of 5 and 10 wt%. For this purpose, blends of rPS and SAN at different ratios, without and with varying concentrations of compatibilizer, were prepared by melt blending using a co-rotating twin-screwextruder. Mechanical properties including tensile and impact strength, rheological properties (RPA), thermal behaviour (DSC) and morphological characteristics (SEM) were evaluated. According to the results obtained by complex viscosity, the blends behave as a pseudoplastic fluid. The results showed that the addition of SEBS increased the Izod impact strength and the elongation at break and decreased the tensile strength and tensile modulus. rPS/SAN blend modified with SEBS had better mechanical properties than the rPS/SAN alloy. SEM photographs revealed that the SEBS was not only distributed in the SAN phase but also distributed in rPS phase in rPS/SAN/SEBS blend. Furthermore, DSC analysis for blends of rPS/SAN gave a good indication of the improvement on miscibility for most compositions. SEM micrographs of tensile fracture surfaces indicated that the formation of the co-continuous phase and the improvement of interface adhesion are the most important reasons for the excellent tensile properties of the rPS/SAN/SEBS blends. Within the range of analysed compositions, the morphologies investigated by SEM are typical of immiscible blends.

关键词： Recycled Polystyrene SAN Toughening Polymer Blends Rheology

Giant and thrombosed left ventricular aneurysm

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World Journal of Cardiology 2015年第7期7卷 431-433页

作者： Jose Alberto de Agustin Jose Juan Gomez de Diego Pedro marcos-Alberca Jose Luis Rodrigo Carlos Almeria Patricia Mahia Maria Luaces miguel angel Garcia-Fernandez Carlos Macaya Leopoldo Perez de Isla Instituto Cardiovascular Hospital Universitario San Carlos

Left ventricular aneurysms are a frequent complication of acute extensive myocardial infarction and are most commonly located at the ventricular apex. A timely diagnosis is vital due to the serious complications that can occur,including heart failure,thromboembolism,or tachyarrhythmias. We report the case of a 78-yearold male with history of previous anterior myocardial infarction and currently under evaluation by chronic heart failure. Transthoracic echocardiogram revealed a huge thrombosed and calcified anteroapical left ventricular aneurysm. Coronary angiography demonstrated that the left anterior descending artery was chronically occluded,and revealed a big and spherical mass with calcified borders in the left hemithorax. Left ventriculogram confirmed that this spherical mass was a giant calcified left ventricular aneurysm,causing very severe left ventricular systolic dysfunction. The patient underwent cardioverter-defibrillator implantation for primary prevention.

关键词： Myocardial infarction Echocardiography Coronary artery disease Left ventricular aneurysm Coronary angiography

Physical and chemical characterization of sediments from an Andean river exposed to mining and agricultural activities: The Moquegua River, Peru

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International Journal of Sediment Research 2022年第6期37卷 780-793页

作者： Luis de Los Santos Valladares Juan Luis Ccamapaza Renato Arturo Valencia-Bedregal Luis Enrique Borja-Castro Jose Velazquez-Garcia Dehiwalage Harshani Nimalika Perera Adrian Ionescu David Arvidsson Eustace Peregrine Barnes Peter Newton Hugo Lepage Patrick Byrne angel Guillermo Bustamante Dominguez Crispin H.W.Barnes Cavendish Laboratory Department of Physics University of Cambridge Escuela Acad emico Profesional de Ingeniería Ambiental Universidad Nacional de Moquegua Provincia de Mariscal Nieto Laboratorio de Cer amicos y Nanomateriales Facultad de Ciencias Físicas Universidad Nacional Mayor de San Marcos School of Biological and Environmental Science Liverpool John Moores University

This study presents an analysis of sediments in an Andean river impacted by both natural conditions and anthropogenic activities. Fifty samples were collected from selected sites throughout the Moquegua River drainage basin, and Tambo River headwaters at Pasto Grande, in Peru, and analysed with X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy and thermogravimetric analysis. Si, Ca, Al, Fe, and O, common constituents of soils, were dominant, along with K, N, and P. The latter originating as primary macronutrients or chemical residuals from fertilizers used in agriculture. Higher concentrations of macronutrients and organic components were found in agricultural and urban areas, respectively. Arsenic minerals were also detected, which occur naturally, but possibly at levels augmented by anthropogenic activity. The application of cluster analysis revealed clustering between arsenic, arsenolite, and potassium but no significant geospatial correlation between sample sites in the drainage basin.

关键词： Andean river Moquegua river Sediments Fourier-transform infrared spectroscopy TG-DTG/DTA Clustering analysis

Structural and Magnetic Properties of Monophasic Maghemite (γ-Fe2O3) Nanocrystalline Powder

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Advances in Nanoparticles 2014年第3期3卷 114-121页

作者： Juan Adrián Ramos Guivar Arturo Isaías Martínez Ana Osorio Anaya Luis De Los Santos Valladares Lizbet León Félix angel Bustamante Dominguez Cavendish Laboratory Department of Physics University of Cambridge Cambridge UK Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional Cinvestav Unidad Saltillo Ciudad de México México Ciudad de México México Laboratorio de Cerámicos y Nanomateriales Facultad de Ciencias Físicas Universidad Nacional Mayor de San Marcos Lima Perú Laboratorio de Nanotecnología e Innovación Tecnológica Departamento de Química e Ingeniería Química Universidad Nacional Mayor de San Marcos Lima Perú Núcleo de Física Aplicada Instituto de Física Universidade de Brasília Brasília Brasil

Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.

关键词： Monophasic Nanomaghemite Rietveld Refinement TEM SAED M-H Loops ZFC

Crystallization and Morphology of Gold Thin Films on Unpolished Si（100） Substrates after Furnace and Flame Annealing

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材料科学与工程（中英文版） 2010年第1期4卷 1-10页

作者： Luis De Los Santos V angel Bustamante D. Lizbet Leon F. Thanos Mitrelias Adrian Ionescu JustinianoQuispe M. Crispin H. W. Barnes Cavendish Laboratory University of Cambridge J. J Thomson .Av. Cambridge CB3 0HE United Kingdom Facultad de Ciencias Fisicas Universidad Nacional Mayor de San Marcos Ap. Postal 14-0149 Peru

Chemical Solution Deposition of YBa2Cu3O7 Films on YSZ （100） Substrates

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Journal of Chemistry and Chemical Engineering 2014年第6期8卷 547-551页

作者： Henry Elías Sanchez Comejo angel Bustamante Dominguez1 Ana María Osorio Luis De Los Santos Valladares José Albino Aguiar Crispin H. W. Barnes Ceramics and Nanomaterials Laboratory Department of Physics Major National University of San Marcos Lima 14-0149 Peru Department of Chemistry and Chemical Engineering Major National University of San Marcos Lima 14-0149 Peru Superconductivity and Advanced Materials Laboratory Department of Physics Federal University of Pernambuco Recife50670-901 Brazil Cavendish Laboratory Department of Physics University of Cambridge Cambridge CB3 0HE United Kingdom

We report the epitaxial growth of YBCO （YBa2Cu3O7） films on YSZ （Yttria-stabilized Zirconia）（100） substrates by chemical solution deposition. The precursor solution was prepared by dissolving stoichiometric amounts of acetates of Y（OOCCH3）3·4H2O, Ba（OOCCH3）2 and Cu（OOCCH3）·2H2O in an aqueous solution of oxalic acid （H2C2O4） and following the sol-gel route. This solution was directly dripped onto YSZ （100） substrates with the help of a Fisher pipette. To form the YBCO film, the sample was crystallized by annealing at 860 ℃ for 12 h in an oxidizing atmosphere. The characterization was performed by XRD （X-ray diffraction） analysis which revealed high intensity （001） reflections and denoted that most of the grains were c-axis oriented. Randomly oriented grains and other phases such as Y2BaCuO5 and CuO were also detected. The superconducting YBCO phase is demonstrated from the susceptibility versus temperature measurements which indicate a superconducting critical temperature ≈ 90 K. In addition, a surface morphology analysis was performed by optical microscopy and atomic force microscopy which revealed an average roughness of 0.2197 μm.

关键词： Sol-gel method epitaxial growth YBCO superconductor layers.

Evolution of Pre-Columbian Metallurgy from the North of Peru Studied with a Portable Non-invasive Equipment Using Energy-Dispersive X-Ray Fluorescence

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材料科学与工程（中英文B版） 2011年第1期1卷 48-81页

作者： Roberto Cesareo angel Bustamante D Julio Fabian S Sandra Zambrano A Walter Alva Luis Chero del Carmen Espinoza C Rosendo Rodriguez R Marco Seclen F Fidel Gutierrez V E.B. Ldvano Gonzales A. Marcia A. Rizzutto Enrico Poli Cristiane Calza Marcelino dos Anjos Ricardo T. Lopes Giovanni E. Gigante Gabriel M. Ingo Cristina Riccucci Carlos Elera Izumi Shimada Victor Curay Castillo G and Fabio Lopes Dipartimento di Matematica e Fisica Universith di Sassari Sassari Italy Universidad Nacional Mayor de San marcos Lima Peri4 Museo ＂Tumbas Reales de Sip6n ＂ Lambayeque Perlt Instituto de Fisica Universidade de S6o Paulo SP Brasil Asociaci6n cultural e Museo Enrico Poli Lima Peru COPPE Universidade Federal do Rio de Janeiro Rio de Janeiro Brasil Dipartimento di Energetica Universith di Roma ＂La Sapienza ＂ Rome Italy lstituto Studio dei Materiali Nanostrutturati-CNR Area Ricerca RM1-Montelibretti Rome Italy Museo de Sic6n Ferrahqfe Perit Istituto Nacional de Cultura Piura Peru Universidade Estadual de Londrina Londrina PR Brasil