The effect of concentration on the Surface-Enhanced Raman Scattering of p-Aminothiophenol

The organic compound p-aminothiophenol (pATP, HS-Ph-NH2) has become very popular because it is often used for checking the enhancement capability of each new SERS substrate due to its very intense SERS spectra. SERS of pATP on silver electrode is significantly different from its ordinary Raman spectra and it is very dependent on the particular conditions of the SERS experiment. In this work the effect of adsorbate concentration on the potential dependent SERS spectra of pATP recorded on a silver electrode has been studied using NaClO4 as electrolyte. On the other hand, MS-CASPT2 have been performed in order to help the analysis of the experimental results by computing resonance Raman spectra of selected structural models of the metal−adsorbate surface complex. It is found that the spectra are dependent on adsorbate concentration and dominated by a resonant charge transfer (CT) mechanism, where the charge is always transferred from the adsorbate to the metal. The relative SERS enhancements are due to Franck−Condon factors related to the CT process, and there are not intensified bands through Herzberg−Teller contributions. Furthermore, the Raman signals of the SERS recorded at low concentration arise from at least three different molecular species: (i) pATP bonded to silver electrode through sulfur atom (Agn-S−-Ph-NH2); (ii) pATP bonded to silver electrode through both sulfur and nitrogen atoms (Agn-S−-PhNH2-Agm); (iii) The azo derivative p,p′-dimercaptoazobenzene (or its nitrene precursor).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Detection of different species of p-aminothiophenol on silver nanoparticles by Surface-Enhanced Raman Spectroscopy (SERS)

In the present work we have analyzed the experimental and theoretical SERS spectra of the organic compound p-aminothiophenol (pATP, HS-Ph-NH2) recorded on silver nanoparticles. DFT calculations have been performed to support the experimental results in order to estimate the adsorption specie and the corresponding Raman bands assignment. It is found a different adsorption behavior of pATP not only by changing the concentration of the adsorbate but also by exciting the sample at different wavelengths.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Comparative Study of p-Aminothiophenol Adsorption by Surface-Enhanced Raman Spectroscopy

The organic compound p-aminothiophenol (PATP, HS-Ph-NH2) has become very popular for checking the enhancement capability of novel substrates due to its very intense SERS spectra. SERS of PATP on metal nanoparticles is significantly different from its ordinary Raman spectra and it is very dependent on the particular experimental conditions. It has been demonstrated that PATP molecule can chemically transform to 4,4′-dimercaptoazobenzene (DMAB) upon adsorption, being this new compound the responsible of giving rise to new SERS bands [1]. In this work, we have studied the adsorption behavior of PATP on different metal substrates: silver electrode [2], silver colloids and bimetallic nanoparticles made of gold and silver. Additionally, theoretical DFT calculations have been performed for supporting the experimental data. The analysis of the SERS results of the PAPT adsorbed on this type of nanoparticles leads us to deduce a very different catalytic capability in the dimerization of this adsorbate that depends directly on the morphology of the nanoparticle. These preliminary but fascinating results on these bimetallic systems are going to be the focus of further experiment in order to quantify the catalytic capabilities of these interesting nanoparticles. REFERENCES 1. Y.F. Huang, H.P. Zhu, G.K. Liu, D.Y. Wu, B. Ren, Z.Q. Tian, When the signal is not from the original molecule to be detected: Chemical transformation of para-Aminothiophenol on ag during the SERS measurement, J. Am. Chem. Soc. 132 (2010) 9244–9246. 2. M.R. Lopez-Ramirez, D. Aranda Ruiz, F.J. Avila Ferrer, S.P. Centeno, J.F. Arenas, J.C. Otero, J. Soto, Analysis of the Potential Dependent Surface-Enhanced Raman Scattering of p-Aminothiophenol on the Basis of MS-CASPT2 Calculations, J. Phys. Chem. C. 120 (2016) 19322–19328.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Enfrentando los riesgos socionaturales

El objetivo del libro es comprender la magnitud de los Riesgos Socionaturales en México y Latinoamérica, para comprender el peligro que existe por algún tipo de desastre, ya sea inundaciones, sismos, remoción en masa, entre otros, además conocer qué medidas preventivas, correctivas y de contingencias existen para estar atentos ante alguna señal que la naturaleza esté enviando y así evitar alguna catástrofe. El libro se enfoca en los aspectos básicos de análisis de los peligros, escenarios de riesgo, vulnerabilidad y resiliencia, importantes para la gestión prospectiva o preventiva

Las ciencias sociales y sus abordajes en los estudios avanzados

Este libro tiene como uno de sus objetivos principales impulsar un ejercicio académico de tipo interdisciplinario entre investigadores y egresados del programa de Doctorado en Ciencias Sociales de la Universidad Autónoma del Estado México (UAEM). Si bien se trata de un esfuerzo incipiente porque los autores que escriben, presentan artículos de investigación en los que desarrollan temas de su campo disciplinar, se trata de un libro relevante porque inaugura una actividad editorial que involucraría a profesores y estudiantes de diferentes líneas de investigación y de distintas disciplinas y les daría la posibilidad de interactuar intelectualmente con el fin de consolidar un diálogo interdisciplinario, que seguramente hará posible desarrollar discusiones de tipo interdisciplinar sobre problemas concretos.Este libro tiene como uno de sus objetivos principales impulsar un ejercicio académico de tipo interdisciplinario entre investigadores y egresados del programa de Doctorado en Ciencias Sociales de la Universidad Autónoma del Estado México (uaem).1 Si bien se trata de un esfuerzo incipiente porque los autores que escriben, presentan artículos de investigación en los que desarrollan temas de su campo disciplinar, se trata de un libro relevante porque inaugura una actividad editorial que involucraría a profesores y estudiantes de diferentes líneas de investigación y de distintas disciplinas y les daría la posibilidad de interactuar intelectualmente con el fin de consolidar un diálogo interdisciplinario,UAE

Ciencias de la Biología y Agronomía

Este volumen I contiene 17 capítulos arbitrados que se ocupan de estos asuntos en Tópicos Selectos de Ciencias de la Biología y Agronomía, elegidos de entre las contribuciones, reunimos algunos investigadores y estudiantes. Se presenta un Estudio Comparativo de los Recursos Hidrológico-Forestales de la Microcuenca de la Laguna de Epatlan, Pue. (1993 a 2014); la Situación Actual de la Mancha de Asfalto en Maíz (Zea mays L.) en los Municipios de Jiquipilas y Ocozocoautla, Chiapas, México; las poblaciones sobresalientes de maíz de la raza Zapalote Chico, en la Región Istmeña de Oaxaca; Se indica el índice de área foliar de cultivo de Chile Poblano mediante dos métodos en condiciones protegidas; Esquivel, Urzúa y Ramírez exploran el efecto de la biofertilización con Azospirillum en el crecimiento y producción de Jitomate; esbozan su artículo sobre la determinación del nivel de Heterosis en híbridos de Maíz para la Comarca Lagunera; una investigación sobre la estabilización de semilla de Solanum lycopersicum durante el almacenamiento y estimulación de la germinación; acotan sobre el CTAB como una nueva opción para la detección de Huanglongbing en cítricos, plantean su evaluación sobre el aluminio y cómo afecta la vida de florero de Heliconia psittacorum; indican sobre el impacto del H-564C, como un híbrido de maíz con alta calidad de proteina para el trópico húmedo de México; presetan su investigación sobre la producción de Piña Cayena Lisa y MD2 (Ananas comosus L.) en condiciones de Loma Bonita, en Oaxaca; acotan sobre el efecto de coberteras como control biológico por conservación contra áfidos en Nogal Pecanero; esbozan sobre la caracterización de cuatro genotipos de Frijol Negro en Martínez de la Torre, Veracruz, México; presentan una caracterización hidroecológica de la microcuenca de Arroyo Prieto, Yuriría, Gto., y alternativas para su restauración ambiental; presentan su investigación sobre el efecto del hongo Beauveria bassiana sobre solubilización de fosfatos y la disponibilidad de fósforo en el suelo; plantean su investigación sobre la Germinación y regeneración in vitro de Epidendrum falcatum LINDL; esbozan su artículo sobre genotipos de frijol negro y su tolerancia a sequía terminal en Veracruz, México

Activating Transcription Factor 4 Modulates TGFβ-Induced Aggressiveness in Triple-Negative Breast Cancer via SMAD2/3/4 and mTORC2 Signaling

Purpose: On the basis of the identified stress-independent cellular functions of activating transcription factor 4 (ATF4), we reported enhanced ATF4 levels in MCF10A cells treated with TGFβ1. ATF4 is overexpressed in patients with triple-negative breast cancer (TNBC), but its impact on patient survival and the underlying mechanisms remain unknown. We aimed to determine ATF4 effects on patients with breast cancer survival and TNBC aggressiveness, and the relationships between TGFβ and ATF4. Defining the signaling pathways may help us identify a cell signaling-tailored gene signature.Experimental Design: Patient survival data were determined by Kaplan-Meier analysis. Relationship between TGFβ and ATF4, their effects on aggressiveness (tumor proliferation, metastasis, and stemness), and the underlying pathways were analyzed in three TNBC cell lines and in vivo using patient-derived xenografts (PDX).Results: ATF4 overexpression correlated with TNBC patient survival decrease and a SMAD-dependent crosstalk between ATF4 and TGFβ was identified. ATF4 expression inhibition reduced migration, invasiveness, mammosphere-forming efficiency, proliferation, epithelial-mesenchymal transition, and antiapoptotic and stemness marker levels. In PDX models, ATF4 silencing decreased metastases, tumor growth, and relapse after chemotherapy. ATF4 was shown to be active downstream of SMAD2/3/4 and mTORC2, regulating TGFβ/SMAD and mTOR/RAC1-RHOA pathways independently of stress. We defined an eight-gene signature with prognostic potential, altered in 45% of 2,509 patients with breast cancer.Conclusions: ATF4 may represent a valuable prognostic biomarker and therapeutic target in patients with TNBC, and we identified a cell signaling pathway-based gene signature that may contribute to the development of combinatorial targeted therapies for breast cancer

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13