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Sample records for p-tfiif rap74 ser

  1. Crystal structure of the C-terminal domain of the RAP74 subunit of human transcription factor IIF

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Katsuhiko; De Angelis, Jacqueline; Roeder, Robert G.; Burley, Stephen K. (Rockefeller)

    2012-12-13

    The x-ray structure of a C-terminal fragment of the RAP74 subunit of human transcription factor (TF) IIF has been determined at 1.02-{angstrom} resolution. The {alpha}/{beta} structure is strikingly similar to the globular domain of linker histone H5 and the DNA-binding domain of hepatocyte nuclear factor 3{gamma} (HNF-3{gamma}), making it a winged-helix protein. The surface electrostatic properties of this compact domain differ significantly from those of bona fide winged-helix transcription factors (HNF-3{gamma} and RFX1) and from the winged-helix domains found within the RAP30 subunit of TFIIF and the {beta} subunit of TFIIE. RAP74 has been shown to interact with the TFIIF-associated C-terminal domain phosphatase FCP1, and a putative phosphatase binding site has been identified within the RAP74 winged-helix domain.

  2. A cDNA encoding RAP74, a general initiation factor for transcription by RNA polymerase II.

    Science.gov (United States)

    Finkelstein, A; Kostrub, C F; Li, J; Chavez, D P; Wang, B Q; Fang, S M; Greenblatt, J; Burton, Z F

    1992-01-30

    RAP30/74 (also known as TFIIF, beta gamma and FC is one of several general factors required for initiation by RNA polymerase II. The small RAP30 subunit of RAP30/74 binds directly to polymerase and appears structurally and functionally homologous to bacterial sigma factors in their RNA polymerase-binding region. RAP30/74 or recombinant RAP30 suppresses nonspecific binding of RNA polymerase II to DNA and is required for RNA polymerase II to assemble stably into a preinitiation complex containing promoter DNA and the general factors TFIID, TFIIA and TFIIB; both RAP30 and RAP74 are physical components of the preinitiation complex. A complementary DNA encoding human RAP30 has been isolated, and here we report the isolation of a cDNA encoding human RAP74. RAP30 and RAP74 produced in Escherichia coli can be used in place of natural human RAP30/74 to direct accurate transcription initiation by RNA polymerase II in vitro.

  3. Deber Ser

    OpenAIRE

    González, A M

    2010-01-01

    1. Ontología del deber ser. 2. Continuidad y diferencia entre consideración ontológica y moral del deber ser. 3. Deber ser moral: a) Relación entre bien y deber; b) Relación entre deber y ley. 4. Dimensión subjetiva y objetiva o institucional del deber. 5. El mal moral: apartarse de la norma/apartarse del fin

  4. Ser maestro

    Directory of Open Access Journals (Sweden)

    Néstor Alonso Sánchez Cardozo

    2015-10-01

    Full Text Available El autor nos presenta una visión formativa de la manera de cómo abordar el trabajo monográfico para obtener el título de licenciado. Su objetivo es el de establecer unas reglas de escritura para la realización de este tipo de ensayo, como un hacer pedagógico de varias manos, donde puedan participar docentes y estudiantes. A través de este ejercicio formativo se viene a estructurar un tipo de escritura, para hacer de él, la razón de ser del futuro egresado en educación: escribir acerca de la cotidianidad escolar.AbstractThe author shows us a formative view of the way about how to board the monographic work in order to get a graduate degree. His objective is to establish some writing rules for this type of essay, as a daily task accomplished by several persons, where educators and students can participate. Through this exercise a type of writing is structured so that it will become the raison d´etre of the graduate-to-be in education : writing about the school daily life.

  5. Ser reina

    Directory of Open Access Journals (Sweden)

    José Manuel NIETO SORIA

    2006-07-01

    Full Text Available L’historiographie du règne des Rois Catholiques, héritière directe de celle des autres Trastamare, se caractérise par son étroite relation avec des enjeux politiques concrets. L’activité historiographie s’est ainsi inscrite elle-même dans le cadre des conflits politiques en cours. C’est pourquoi la royauté d’Isabelle Ire de Castille impliqua une bonne part de la production historiographique de cettte époque : soit qu’on dénonçât un déficit de légitimité dû à sa condition féminine, soit qu’on démentît, au contraire, ce déficit en attribuant à la reine des qualités « masculines ». Bien entendu, ces débats furent fonction de l’engagement politique de chacun des historiens.La cronística y la historiografía del reinado de los Reyes Católicos, como directas herederas de la labor historiográfica de la época de los monarcas Trastámara, se caracterizó por su estrecha vinculación con intereses políticos concretos, inscribiéndose la propia actividad historiográfica en el marco de los conflictos políticos en curso. Por ello, la dimensión regia de Isabel I de Castilla supuso una dimensión significativa del quehacer historiográfico de la época, bien para plantear un déficit de legitimidad por razón de su propia condición femenina, bien para negar tal déficit con la atribución de “cualidades masculinas” en su persona. De este modo, la toma en consideración del hecho de “ser reina” representó una dimensión significativa del quehacer historiográfico, de acuerdo siempre con los compromisos políticos de los distintos historiadores de la época.

  6. Ser humano: Ser-en-la-existencia

    Directory of Open Access Journals (Sweden)

    Víctor Ricardo Moreno Holguín

    2014-01-01

    Full Text Available Es necesario superar el discurso sobre el SER y la Existencia para adentrarse en un camino práctico, que redescubre el dinamismo de la existencia de la persona humana como presencia encarnada del SER. Guiados por las palabras del místico Maestro Eckhart de Hochheim se redescubre al SER como Principio y Fundamento de la esencia de la perso- na, (SER al que buena parte de la humanidad ha llamado “Dios”, que por medio de diversas ma- nifestaciones percibidas a nivel psicológico, parece llamarlo al reencuentro. Por esto conviene ampliar la mirada para releer manifestaciones tales como la ansiedad y los estados emocionales incomprendidos por quienes los padecen y que la medicina tradicio- nal los trata como situaciones estáticas, como signos de un proceso dinámico en el alma. Así es nece- saria una psicología del Camino Interior durante el proceso que la persona realiza hasta acceder al Ser esencial. Este Camino Interior incluye la liberación de la dictadura de las emociones y de otras dolencias del alma. Finaliza este artículo con una anotación a una práctica que puede orientar hacia dónde dirigir la mirada cuando se opta por el Camino Interior; la práctica del sentarse, como no-acción y recogimien- to interior, el vivir con plena atención y mantener la respiración correcta, como se practica en muchos monasterios, que además de alejar del activismo y el frenesí de la cotidianidad, abre las puertas para el descubrimiento interior del ser humano como SER hecho Existencia

  7. Security effectiveness review (SER)

    Energy Technology Data Exchange (ETDEWEB)

    Kouprianova, I. [Inst. of Physics and Power Engineering, Obninsk (Russian Federation); Ek, D.; Showalter, R. [Sandia National Labs., Albuquerque, NM (United States); Bergman, M. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    As part of the on-going DOE/Russian MPC and A activities at the Institute of Physics and Power Engineering (IPPE) and in order to provide a basis for planning MPC and A enhancements, an expedient method to review the effectiveness of the MPC and A system has been adopted. These reviews involve the identification of appropriate and cost-effective enhancements of facilities at IPPE. This effort requires a process that is thorough but far less intensive than a traditional vulnerability assessment. The SER results in a quick assessment of current and needed enhancements. The process requires preparation and coordination between US and Russian analysts before, during, and after information gathering at the facilities in order that the analysis is accurate, effective, and mutually agreeable. The goal of this paper is to discuss the SER process, including the objectives, time scale, and lessons learned at IPPE.

  8. Aprendendo a ser psicoterapeuta

    Directory of Open Access Journals (Sweden)

    Elizabeth Amelio Faleiros

    Full Text Available Este estudo investiga, na perspectiva de Jacob Levy Moreno, a concepção que alunos de Psicologia têm sobre o que é ser psicoterapeuta, quais elementos são necessários para o desenvolvimento dessa tarefa e os fatores impeditivos para realizá-la. Propõe formas de soluções para o desempenho daquela função, favorecendo a reflexão sobre a importância dessa tarefa e a responsabilidade do profissional junto ao paciente. A metodologia utilizada é a qualitativa, pois esta permite abordar dimensões da subjetividade dos sujeitos. Os resultados revelam que os alunos possuem em sua concepção os alicerces básicos, cujos indicadores são apontados por Moreno e por outros autores, percebem os requisitos básicos que constituem a essência do papel de terapeuta, evidenciam críticas realistas sobre os fatores limitadores e sugerem ações pedagógicas para minimizá-los.

  9. Tuning SERS for living erythrocytes

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Parshina, E.Y.; Khabanova, V.V.;

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) is a unique technique to study submembrane hemoglobin (Hbsm) in erythrocytes. We report the detailed design of SERS experiments on living erythrocytes to estimate dependence of the enhancemen t factor for main Raman bands of Hbsm on silver nanoparticle (Ag...

  10. Vinte anos de efeito SERS Twenty years of SERS

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    Dalva L. A. de Faria

    1999-07-01

    Full Text Available The Surface Enhanced Raman Scattering (SERS effect was observed for the first time in 1974, but it was only considered a new effect three years later, hence, nearly twenty years ago. Since its discovery, a significant amount of investigations have been performed aiming at to clarify the nature of the observed enhancement, to improve the surface stability and to establish applications which nowadays range from the study of biomolecules to catalysis. Some of the more relevant aspects of this effect which have been examined across the last two decades are summarized in this paper which presents the introductory aspects of SERS alongside with several of its applications.

  11. Stamping SERS for creatinine sensing

    Science.gov (United States)

    Li, Ming; Du, Yong; Zhao, Fusheng; Zeng, Jianbo; Santos, Greggy M.; Mohan, Chandra; Shih, Wei-Chuan

    2015-03-01

    Urine can be obtained easily, readily and non-invasively. The analysis of urine can provide metabolic information of the body and the condition of renal function. Creatinine is one of the major components of human urine associated with muscle metabolism. Since the content of creatinine excreted into urine is relatively constant, it is used as an internal standard to normalize water variations. Moreover, the detection of creatinine concentration in urine is important for the renal clearance test, which can monitor the filtration function of kidney and health status. In more details, kidney failure can be imminent when the creatinine concentration in urine is high. A simple device and protocol for creatinine sensing in urine samples can be valuable for point-of-care applications. We reported quantitative analysis of creatinine in urine samples by using stamping surface enhanced Raman scattering (S-SERS) technique with nanoporous gold disk (NPGD) based SERS substrate. S-SERS technique enables label-free and multiplexed molecular sensing under dry condition, while NPGD provides a robust, controllable, and high-sensitivity SERS substrate. The performance of S-SERS with NGPDs is evaluated by the detection and quantification of pure creatinine and creatinine in artificial urine within physiologically relevant concentration ranges.

  12. ser en ortodoncia

    OpenAIRE

    2014-01-01

    La primera aplicación del láser en un diente fue realizada en 1965. Desde entonces ha presentado una constante evolución y desarrollo. La tecnología láser permite realizar procedimientos en tejidos duros y blandos, pudiendo ser utilizado con las siguientes finalidades: como prevención de la desmineralización, en la adhesión y remoción de brackets, en la reducción del dolor producto del movimiento dental, en la reparación ósea después de la expansión, en diversas cirugías y otras aplicaciones ...

  13. ser en ortodoncia

    OpenAIRE

    Ruíz-Esculpi, María; Universidad Central de Venezuela. Caracas.; Ricse-Chaupis, Estela; Universidad de San Martín de Porres. Lima.; Villanueva-Vega, Judith; Universidad Nacional Mayor de San Marcos. Lima.; Torres-Maita, Liz; Facultad de Estomatología, Universidad Peruana Cayetano Heredia. Lima.

    2014-01-01

    La primera aplicación del láser en un diente fue realizada en 1965. Desde entonces ha presentado una constante evolución y desarrollo. La tecnología láser permite realizar procedimientos en tejidos duros y blandos, pudiendo ser utilizado con las siguientes finalidades: como prevención de la desmineralización, en la adhesión y remoción de brackets, en la reducción del dolor producto del movimiento dental, en la reparación ósea después de la expansión, en diversas cirugías y otras aplicaciones ...

  14. Single Bacterium Detection Using Sers

    Science.gov (United States)

    Gonchukov, S. A.; Baikova, T. V.; Alushin, M. V.; Svistunova, T. S.; Minaeva, S. A.; Ionin, A. A.; Kudryashov, S. I.; Saraeva, I. N.; Zayarny, D. A.

    2016-02-01

    This work is devoted to the study of a single Staphylococcus aureus bacterium detection using surface-enhanced Raman spectroscopy (SERS) and resonant Raman spectroscopy (RS). It was shown that SERS allows increasing sensitivity of predominantly low frequency lines connected with the vibrations of Amide, Proteins and DNA. At the same time the lines of carotenoids inherent to this kind of bacterium are well-detected due to the resonance Raman scattering mechanism. The reproducibility and stability of Raman spectra strongly depend on the characteristics of nanostructured substrate, and molecular structure and size of the tested biological object.

  15. SERS sensors for DVD platform

    DEFF Research Database (Denmark)

    Brøgger, Anna Line

    This Ph.D. thesis explores the engineering of a portable sensor system for detection of rare and small molecules. The Ph.D. project is part of the research project 'Multi-Sensor DVD platform' (MUSE), aiming to integrate different sensors on a rotating disc. The sensors are chosen to complement each...... other, creating more reliable and stable results for the end user. The rotating disc comprises microfluidic channels, which can be utilized for handling and manipulating liquid samples such as blood or water. The focus of this Ph.D. thesis, is on the integration of one specific sensor on a rotating disc....... The sensor is based upon surface enhanced Raman spectroscopy (SERS), which detects molecular vibrations. The aim of this thesis is to cover the different aspects of the sensor system. SERS substrates, consisting of nanopillars with gold or silver caps on top, have been fabricated by standard micro and nano...

  16. El hombre, ser de palabra

    OpenAIRE

    Presas, Mario A.

    2006-01-01

    RESUMEN: Paul Ricoeur distingue la mismidad del carácter (idem), de la ipseidad, el ser que se mantiene en la promesa, el maintien de soi, que encuentra su más fiel expresión en las variaciones imaginarias de la ficción literaria. El presente trabajo analiza obras no tenidas en cuenta por Ricoeur, como Kaspar de Peter Handke, para ejemplificar la pérdida de la ipseidad si no hay un juego dialéctico con un carácter, caso que también se muestra en Der Mann ohne Eigenschaften de Musil. Un "sueño...

  17. Ser poeta: poemas al llano

    OpenAIRE

    1999-01-01

    "Ser poeta es viajar sobre mares revueltos y soltar las amarras sin pensar en el puerto" El alma de un poeta como Getulio, viajará eternamente solitaria por los caminos del llano. Sus versos no morirán jamás. En la medida en que pase el tiempo se tornarán en el alma del folklore llanero y los repetirá el eco solitario de las sabanas en las noches de luna. Getulio lleva el verso a flor de labios, su alma es poesía. Le parece que ve crecer las plantas, abrirse las flores en las mañanas,...

  18. por láser

    Directory of Open Access Journals (Sweden)

    Mayra Garcimuño

    2013-01-01

    Full Text Available En el presente trabajo, la técnica Espectroscopia de plasmas producidos por láser (Laser-induced breakdown spectroscopy –LIBS– se aplicó a la determinación cuan- titativa de Na en agua natural dulce, de interés en agricultura para el estudio de la alcalinidad de aguas de regadío. Para efectuar el análisis, se prepararon soluciones con concentraciones conocidas del analito, se mezclaron con óxido de calcio y se compactaron en pastillas sólidas. Los plasmas se produjeron en aire a presión atmos- férica utilizando un láser pulsado Nd:YAG. Se construyó una curva de calibración y se calculó el límite de detección. Se analizaron muestras de agua natural y los resultados se compararon con los obtenidos mediante espectroscopia de absorción atómica. Se demostró la factibilidad del método para la determinación de Na en agua natural dulce.

  19. Flexible SERS Substrates: Challenges and Opportunities

    Science.gov (United States)

    2016-01-28

    multifunctionality to SERS substrates to achieve separation, preconcentration and detection on flexible SERS substrates. Clearly, progress along this...developed a microfluidic device that detects trace concentrations of drugs of abuse in saliva within minutes using SERS . Its operation was demonstrated...substrates without hot spots are demonstrated with SERS enhancements near 108 compared to non-enhancing substrates for the detection of benzenethiol. The

  20. El Hombre, un ser integral

    Directory of Open Access Journals (Sweden)

    Gabriel Alexander Solórzano

    2008-12-01

    Full Text Available El artículo pretende mostrar la dificultad que existe al momento de elaborar una precisa definición del hombre como ser integral, para ello se recurre a las nociones esenciales de la antropología filosófica, la nueva concepción del giro cristia- no de la fenomenología francesa, se mira grosso modo la visión personalista de Juan Pablo II sobre el hombre y la visión integradora de Panikkar del humanismo cosmote- ándrico, por último se encuentra la visión del humanismo cristiano y el desarrollo soli- dario enfatizado en el Magisterio de la Iglesia Católica como intento de respuesta a la crucial pregunta sobre el hombre y su mundo relacional. Palabras clave: Filosofía, Teología moral, Fenomenología, Humanismo, Perso- nalismo, Cosmoteándrico. 

  1. for SERS and Photocatalytic Applications

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    Xue Chen

    2011-01-01

    Full Text Available ZnS/Si nanocables were synthesized via a simple two-step thermal evaporation method. The shape and diameter of the ZnS/Si nanocables can be controlled by adjusting the morphologies of the ZnS nanostructures (nanowire or nanoribbon obtained in the first step and the deposition time of the Si shell in the second step, respectively. Furthermore, we obtained polycrystalline Si nanotubes with different shapes and diameters by etching away the inner ZnS core. The as-prepared Si nanotubes were employed as SERS-active substrates, which exhibited a high sensitivity for the detection of R6G. The Si nanotubes also showed effective photocatalytic activity on the decomposition of R6G under the irradiation of visible light.

  2. Ser marrano em Minas Colonial

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    Anita Novinsky

    2001-01-01

    Full Text Available Baseado em 57 Processos inéditos de marranos (cristãos-novos, conversos presos em Minas Gerais no século XVIII, este artigo procura mostrar seu papel na Idade de Ouro do Brasil. 64% deles eram mercadores e 23% eram mineiros. Pertenciam à classe média e raros eram os magnatas. Nenhum dele esteve envolvido no tráfico negreiro. Acusados do crime de judaísmo e de pertencerem a sociedades secretas, representaram 42% dos brasileiros condenados à morte. Ser marrano entre os portugueses no Brasil mais um sentimento e uma visão de mundo do que uma prática religiosa.Based on 57 unknown trials of marranos (new christians, conversos arrested by the Inquisition in Minas Gerais in the XVIII the century, this article shows their role in shapping the history of Minas Gerais. 64% of them were merchants na 23% were miners. Most of them belonged to a middle class and rare were those whit great fortunes. No one of them were engaged in slave trade. Acused of judaism and of participating in secret society the marranos of Minas represented 42% of the Brazilian burned at the stake. Being a marrano in Minas Gerais was not always being a crypto-new. Marranism in Brasil was a feeling and a approach to life.

  3. Standard method for characterizing SERS substrates

    Science.gov (United States)

    Guicheteau, Jason A.; Hankus, Mikella E.; Christesen, Steven D.; Fountain, Augustus W., III; Pellegrino, Paul M.; Emmons, Erik D.; Tripathi, Ashish; Wilcox, Phillip; Emge, Darren

    2012-06-01

    We present the methodology and results of a standard assessment protocol to evaluate disparate SERS substrates that were developed for the Defense Advanced Research Programs Agency (DARPA) SERS Science and Technology Fundamentals Program. The results presented are a snapshot of a collaborative effort between the US Army Edgewood Chemical Biological Center, and the US Army Research Laboratory-Aldelphi Laboratory Center to develop a quantitative analytical method with spectroscopic figures of merit to unambiguously compare the sensitivity and reproducibility of various SERS substrates submitted by the program participants. We present the design of a common assessment protocol and the definition of a SERS enhancement value (SEV) in order to effectively compare SERS active surfaces.

  4. Review of SERS Substrates for Chemical Sensing

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-06-01

    Full Text Available The SERS effect was initially discovered in the 1970s. Early research focused on understanding the phenomenon and increasing enhancement to achieve single molecule detection. From the mid-1980s to early 1990s, research started to move away from obtaining a fundamental understanding of the phenomenon to the exploration of analytical applications. At the same time, significant developments occurred in the field of photonics that led to the advent of inexpensive, robust, compact, field-deployable Raman systems. The 1990s also saw rapid development in nanoscience. This convergence of technologies (photonics and nanoscience has led to accelerated development of SERS substrates to detect a wide range of chemical and biological analytes. It would be a monumental task to discuss all the different kinds of SERS substrates that have been explored. Likewise, it would be impossible to discuss the use of SERS for both chemical and biological detection. Instead, a review of the most common metallic (Ag, Cu, and Au SERS substrates for chemical detection only is discussed, as well as SERS substrates that are commercially available. Other issues with SERS for chemical detection have been selectivity, reversibility, and reusability of the substrates. How these issues have been addressed is also discussed in this review.

  5. Development of SERS active fibre sensors

    CERN Document Server

    Polwart, E

    2002-01-01

    Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a...

  6. Conocer y ser en el paradigma constructivista

    Directory of Open Access Journals (Sweden)

    Jose Antonio Camargo Rodriguez

    2014-03-01

    Full Text Available Toda teoría acerca del aprendizaje se fundamenta en una interpretación del conocimiento, la cual se encuentra, a su vez, ligada a una cierta concepción de «ser». No será posible asimilar verdaderamente cualquiera de tales teorías si se ignoran, o no se consideran con el debido detenimiento, las ideas de conocer y «ser» que le sirven de base. Sc pone de presente que el constructivismo, en contraste con la teoría transmisionista de la enseñanza y el aprendizaje, predominante en la pedagogía tradicional, tiene su fundamento en la interpretación según la cual el conocer es una actividad humana en la que, a medida quo conoce, el hombre construye el «ser». Antes de todo conocimiento, las cosas no tienen un «ser»; están ahí, pero no se sabe lo que son. El «ser», quo constituye el objeto de todo conocer, aquello que el sujeto persigue a través de su conocimiento, no toes dada de antemano, ni le viene de fuera, sino quo es una elaboración quo el mismo realiza a través de su actividad cognoscitiva, un contenido de su propia conciencia. Hay, pues, una cierta paradoja entre las ideas de conocer y «ser» que sirven de fundamento al constructivismo, cuya reflexión se propone en aras de ganar una mejor comprensión, de encontrarle a este paradigma un sentido más allá de la pedagogía y la didáctica.

  7. The detection of dust around NN Ser

    Science.gov (United States)

    Hardy, Adam; Schreiber, Matthias R.; Parsons, Steven G.; Caceres, Claudio; Brinkworth, Carolyn; Veras, Dimitri; Gänsicke, Boris T.; Marsh, Thomas R.; Cieza, Lucas

    2016-07-01

    Eclipse timing variations observed from the post-common-envelope binary (PCEB) NN Ser offer strong evidence in favour of circumbinary planets existing around PCEBs. If real, these planets may be accompanied by a disc of dust. We here present the ALMA detection of flux at 1.3 mm from NN Ser, which is likely due to thermal emission from a dust disc of mass ˜0.8 ± 0.2 M⊕. We performed simulations of the history of NN Ser to determine possible origins of this dust, and conclude that the most likely origin is, in fact, common-envelope material which was not expelled from the system and instead formed a circumbinary disc. These discs have been predicted by theory but previously remained undetected. While the presence of this dust does not prove the existence of planets around NN Ser, it adds credibility to the possibility of planets forming from common-envelope material in a `second-generation' scenario.

  8. Hur ser egentligen AKK-samspel ut?

    DEFF Research Database (Denmark)

    Pilesjö, Maja Sigurd

    Hur ser egentligen AKK-samspel ut? Interaktionsmönster mellan barn med omfattande kommunikativ och motorisk funktionsnedsättning och deras vardagliga samtalspartners. Hur kan egentligen samspel mellan barn med kommunikationsvårighe- ter gå till och faktiskt också fung- era? Maja Sigurd Pilesjö...

  9. Plasmonic SERS biosensing nanochips for DNA detection.

    Science.gov (United States)

    Ngo, Hoan T; Wang, Hsin-Neng; Fales, Andrew M; Vo-Dinh, Tuan

    2016-03-01

    The development of rapid, cost-effective DNA detection methods for molecular diagnostics at the point-of-care (POC) has been receiving increasing interest. This article reviews several DNA detection techniques based on plasmonic-active nanochip platforms developed in our laboratory over the last 5 years, including the molecular sentinel-on-chip (MSC), the multiplex MSC, and the inverse molecular sentinel-on-chip (iMS-on-Chip). DNA probes were used as the recognition elements, and surface-enhanced Raman scattering (SERS) was used as the signal detection method. Sensing mechanisms were based on hybridization of target sequences and DNA probes, resulting in a distance change between SERS reporters and the nanochip's plasmonic-active surface. As the field intensity of the surface plasmon decays exponentially as a function of distance, the distance change in turn affects SERS signal intensity, thus indicating the presence and capture of the target sequences. Our techniques were single-step DNA detection techniques. Target sequences were detected by simple delivery of sample solutions onto DNA probe-functionalized nanochips and measuring the SERS signal after appropriate incubation times. Target sequence labeling or washing to remove unreacted components was not required, making the techniques simple, easy-to-use, and cost-effective. The usefulness of the nanochip platform-based techniques for medical diagnostics was illustrated by the detection of host genetic biomarkers for respiratory viral infection and of the dengue virus gene.

  10. Ver y ser visto en Calicalabozo

    Directory of Open Access Journals (Sweden)

    Santiago Guevara

    2014-01-01

    Full Text Available El presente artículo pretende dar cuenta de la manera en que el territorio urbano es presentado en el libro de cuentos Calicalabozo de Andrés Caicedo. Se analiza la dicotomía; ver y ser visto. El objetivo es brindar una aproximación al imaginario de la ciudad que Caicedo propone en su libro.

  11. Enseñar a ser

    OpenAIRE

    García Barreno, Pedro

    2004-01-01

    El «Informe Delors», cuyo texto fue presentado hace ahora diez años, señala que cualquier proyecto educativo para el siglo XXI debe contemplar dos acciones. «Enseñar a conocer, a hacer, a vivir juntos, a ser», y garantizar el acceso de todos a ello. El siglo que concluyó apenas media docena de años, ha estado cargado de inmensas paradojas: entre grandes males, extraordinarios logros y no pocas esperanzas inalcanzadas. Marcado por dos guerras mundiales, po...

  12. ConoSer en la Universidad

    Directory of Open Access Journals (Sweden)

    Nina Cabra

    2007-10-01

    Full Text Available La Universidad contemporánea debe asumir la pregunta por las formas de comunicación-educación que dinamiza en su seno. La necesidad de superar los modelos transmisionistas, implica la configuración de nuevos viajes en la formación, en la investigación y en la gestión de procesos sociales. Este artículo presenta una reflexión sobre las posibilidades del cuerpo y la sensibilidad como fuentes de conocimiento, exploración del ser y catalizadores del pensar en el hacer de la Universidad.

  13. ConoSer en la Universidad

    OpenAIRE

    Nina Cabra

    2007-01-01

    La Universidad contemporánea debe asumir la pregunta por las formas de comunicación-educación que dinamiza en su seno. La necesidad de superar los modelos transmisionistas, implica la configuración de nuevos viajes en la formación, en la investigación y en la gestión de procesos sociales. Este artículo presenta una reflexión sobre las posibilidades del cuerpo y la sensibilidad como fuentes de conocimiento, exploración del ser y catalizadores del pensar en el hacer de la Universidad.

  14. internacionales ser considerados actos no justiciables?

    Directory of Open Access Journals (Sweden)

    Eleonora Mesquita Ceia

    2007-01-01

    Full Text Available La premisa del presente artículo es que el control de constitucionalidad de los tratados internacionales puede afectar a la política exterior del Ejecutivo. A partir de esta hipótesis, el autor analiza si dichos instrumentos deben ser considerados actos no justiciables, o si en el caso de que el argumento a favor de la justiciabilidad prevalezca, si ellos deben por lo menos merecer un tratamiento especial. La cuestión será examinada desde cuatro perspectivas jurídicas diferentes: la estadounidense, la francesa, la alemana y la brasileña. Basado en los resultados de este análisis legal comparativo, el artículo concluye a favor de la justiciabilidad de los tratados internacionales y, por otra parte, propone una alternativa que proporcione el equilibrio entre el principio de la separación de poderes y el carácter complejo de las relaciones internacionales.

  15. Hollow plasmonic antennas for broadband SERS spectroscopy.

    Science.gov (United States)

    Messina, Gabriele C; Malerba, Mario; Zilio, Pierfrancesco; Miele, Ermanno; Dipalo, Michele; Ferrara, Lorenzo; De Angelis, Francesco

    2015-01-01

    The chemical environment of cells is an extremely complex and multifaceted system that includes many types of proteins, lipids, nucleic acids and various other components. With the final aim of studying these components in detail, we have developed multiband plasmonic antennas, which are suitable for highly sensitive surface enhanced Raman spectroscopy (SERS) and are activated by a wide range of excitation wavelengths. The three-dimensional hollow nanoantennas were produced on an optical resist by a secondary electron lithography approach, generated by fast ion-beam milling on the polymer and then covered with silver in order to obtain plasmonic functionalities. The optical properties of these structures have been studied through finite element analysis simulations that demonstrated the presence of broadband absorption and multiband enhancement due to the unusual geometry of the antennas. The enhancement was confirmed by SERS measurements, which showed a large enhancement of the vibrational features both in the case of resonant excitation and out-of-resonance excitation. Such characteristics indicate that these structures are potential candidates for plasmonic enhancers in multifunctional opto-electronic biosensors.

  16. Enseñar a ser

    Directory of Open Access Journals (Sweden)

    García Barreno, Pedro

    2004-09-01

    Full Text Available El «Informe Delors», cuyo texto fue presentado hace ahora diez años, señala que cualquier proyecto educativo para el siglo XXI debe contemplar dos acciones. «Enseñar a conocer, a hacer, a vivir juntos, a ser», y garantizar el acceso de todos a ello. El siglo que concluyó apenas media docena de años, ha estado cargado de inmensas paradojas: entre grandes males, extraordinarios logros y no pocas esperanzas inalcanzadas. Marcado por dos guerras mundiales, por genocidios, por la acelerada degradación de la biosfera o por la miseria de una masa de marginados frente al creciente bienestar de los privilegiados.…

  17. euro a ser una moneda internacional

    Directory of Open Access Journals (Sweden)

    María Hortensia Lacayo Ojeda

    2001-01-01

    Full Text Available En este trabajo se estudia cuáles son los principales factores económicos y financieros que llevan al euro, la nueva moneda común europea, a ser una moneda internacional junto al dólar y al yen. Entre dichos factores se encuentran, en primer lugar, el respaldo económico de los doce países de la Unión Económica y Monetaria medido a través de su importancia demográfica, su producto interno bruto (PIB y su grado de apertura comercial; en segundo lugar, la dimensión financiera de la zona euro en lo referente a las inversiones realizadas en la moneda europea, su utilización como moneda de reserva y como moneda de intercambio; en tercer término, la confianza que inspire el euro a los actores económicos

  18. SERS detection of biomolecules using lithographed nanoparticles towards a reproducible SERS biosensor

    Energy Technology Data Exchange (ETDEWEB)

    David, Catalina; Guillot, Nicolas; Chapelle, Marc Lamy de la [Laboratoire CSPBAT (FRE 3043), UFR SMBH, Universite Paris XIII, 74 rue Marcel Cachin, F-93017 Bobigny (France); Shen, Hong; Toury, Timothee, E-mail: marc.lamydelachapelle@univ-paris13.fr [ICD-LNIO-UMR, CNRS 6279, Universite de technologie de Troyes, 12 rue Marie Curie, F-10010 Troyes (France)

    2010-11-26

    In this paper we highlight the accurate spectral detection of bovine serum albumin and ribonuclease-A using a surface-enhanced Raman scattering (SERS) substrate based on gold nanocylinders obtained by electron-beam lithography (EBL). The nanocylinders have diameters from 100 to 180 nm with a gap of 200 nm. We demonstrate that optimizing the size and the shape of the lithographed gold nanocylinders, we can obtain SERS spectra of proteins at low concentration. This SERS study enabled us to estimate high enhancement factors (10{sup 5} for BSA and 10{sup 7} for RNase-A) of important bands in the protein Raman spectrum measured for 1 mM concentration. We demonstrate that, to reach the highest enhancement, it is necessary to optimize the SERS signal and that the main parameter of optimization is the LSPR position. The LSPR have to be suitably located between the laser excitation wavelength, which is 632.8 nm, and the position of the considered Raman band. Our study underlines the efficiency of gold nanocylinder arrays in the spectral detection of proteins.

  19. Feasibility of colloidal silver SERS for rapid bacterial screening

    Science.gov (United States)

    Citrate-reduced silver colloids have been used extensively for surface-enhanced Raman scattering (SERS) study and are commonly characterized by UV-visible spectroscopy. In this work, relative standard deviation (RSD) of SERS spectra from silver colloidal suspensions and ratios of SERS peaks from sma...

  20. Heidegger y la pregunta por el sentido del ser

    OpenAIRE

    2010-01-01

    La contribución más duradera de Heidegger a la filosofía de nuestra época consiste en la defensa del cometido «ontológico» de la filosofía. En su amplio itinerario planteó la pregunta por el ser de tres maneras: como pregunta por el sentido del ser, la verdad del ser y el lugar del ser. En este artículo examinaremos críticamente su primera formulación: la que desembocó en una de las obras más influyentes del siglo XX, "Ser y tiempo".

  1. The planets around NN Ser: still there

    CERN Document Server

    Marsh, T R; Bours, M C P; Littlefair, S P; Copperwheat, C M; Dhillon, V S; Breedt, E; Caceres, C; Schreiber, M R

    2013-01-01

    We present 25 new eclipse times of the white dwarf binary NN Ser taken with the high-speed camera ULTRACAM on the WHT and NTT, the RISE camera on the Liverpool Telescope, and HAWK-I on the VLT to test the two-planet model proposed to explain variations in its eclipse times measured over the last 25 years. The planetary model survives the test with flying colours, correctly predicting a progressive lag in eclipse times of 36 seconds that has set in since 2010 compared to the previous 8 years of precise times. Allowing both orbits to be eccentric, we find orbital periods of 7.9 +/- 0.5 yr and 15.3 +/- 0.3 yr, and masses of 2.3 +/- 0.5 Mjup and 7.3 +/- 0.3 Mjup. We also find dynamically long-lived orbits consistent with the data, associated with 2:1 and 5:2 period ratios. The data scatter by 0.07 seconds relative to the best-fit model, by some margin the most precise of any of the proposed eclipsing compact object planet hosts. Despite the high precision, degeneracy in the orbit fits prevents a significant measu...

  2. Libertas que serás enfermagem

    Directory of Open Access Journals (Sweden)

    Mary Anne Fontenele Martins

    1998-09-01

    Full Text Available O título deste ensaio nos faz lembrar a Inconfidência Mineira, que teve como líder José Joaquim da Silva Xavier, o Tiradentes, sendo um movimento que ansiava por liberdade, assim como a enfermagem que, ao longo dos anos, vem construindo sua história e caminhando em busca de sua autonomia. A presente pesquisa tem como objetivo investigar os caminhos percorridos pela enfermagem, enquanto ciência na busca de sua autonomia, e refletir sobre a atuação do enfermeiro enquanto profissional criativo e autônomo. Estudo respaldado no materialismo histórico e dialético, realizado no período de maio a agosto de 1997 com enfermeiras do Estado do Ceará, que estão envolvidas com o processo histórico da profissão. Os resultados deram origem a uma categoria central, prática profissional e outras três: autonomia, criatividade e disposição para enfrentar desafios, que favoreceram uma melhor compreensão dos caminhos já trilhados pela enfermagem, além de nos permitir entender que o enfermeiro pode ser autônomo e livre.

  3. MODOS DE SER DA JUVENTUDE OCIDENTAL

    Directory of Open Access Journals (Sweden)

    Prof. Dr. Luiz Antônio Dias

    2015-09-01

    Full Text Available O presente artigo é resultado de investigações ainda em andamento no Grupo de Pesquisa “Culturas juvenis, consumo e mobilidade urbana na contemporaneidade”, iniciadas em 2013 junto ao Programa de Mestrado Interdisciplinar em Ciências Humanas da Universidade de Santo Amaro (UNISA. A pesquisa dedica-se a entender, entre outras reflexões, o percurso dos jovens na sociedade contemporânea e as contribuições que eles trouxeram para repensar o espaço urbano. Nesse estudo buscamos localizar no espaço e no tempo em quais condições históricas o sentimento de juventude apareceu para a sociedade. Em seguida, fazemos um minucioso levantamento da trajetória dessa nova categoria social nos mais diferentes períodos da história contemporânea. Chegamos, assim, ao século XX, momento em que as reuniões juvenis deixam de ser fatos isolados e adquirem conotações de manifestações verdadeiramente sociais. Ainda nessa perspectiva de análise, buscamos compreender as similitudes, aproximações e distanciamentos do movimento punk com seus congêneres do passado.

  4. Paraplejia: pasado y futuro del ser

    Directory of Open Access Journals (Sweden)

    María Elisa Moreno-Fergusson

    Full Text Available El propósito del artículo es presentar una síntesis de la literatura publicada entre 1988 y 2008 sobre los cambios en la corporalidad de las personas con paraplejia secundaria a un trauma raquimedular y su relevancia para el cuidado de enfermería. La revisión incluyó 22 estudios cualitativos, 5 cuantitativos y 20 piezas documentales, publicadas por profesionales de la salud y de las ciencias humanas. Los resultados permiten concluir que las secuelas del trauma raquimedular causan dependencia, alteran la imagen corporal, la interacción social, el sentido de coherencia del ser y la corporalidad. Con el tiempo, estas personas, re-conocen su "nuevo cuerpo" y construyen una nueva corporalidad, proceso que aún no ha sido descrito y que se considera fundamental para el cuidado de enfermería, encaminado a ayudar a las personas con este tipo de lesión para lidiar con las dificultades cotidianas.

  5. Unique Gold Nanoparticle Aggregates as a Highly Active SERS Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzberg, A M; Grant, C D; Wolcott, A; Talley, C E; Huser, T R; Bogomolni, R; Zhang, J Z

    2004-04-06

    A unique gold nanoparticle aggregate (GNA) system has been shown to be an excellent substrate for surface-enhanced Raman scattering (SERS) applications. Rhodamine 6G (R6G), a common molecule used for testing SERS activity on silver, but generally difficult to detect on gold substrates, has been found to readily bind to the GNA and exhibit strong SERS activity due to the unique surface chemistry afforded by sulfur species on the surface. This GNA system has yielded a large SERS enhancement of 10{sup 7}-10{sup 9} in bulk solution for R6G, on par with or greater than any previously reported gold SERS substrate. SERS activity has also been successfully demonstrated for several biological molecules including adenine, L-cysteine, L-lysine, and L-histidine for the first time on a gold SERS substrate, showing the potential of this GNA as a convenient and powerful SERS substrate for biomolecular detection. In addition, SERS spectrum of R6G on single aggregates has been measured. We have shown that the special surface properties of the GNA, in conjunction with strong near IR absorption, make it useful for SERS analysis of a wide variety of molecules.

  6. Ultrasensitive sliver nanorods array SERS sensor for mercury ions.

    Science.gov (United States)

    Song, Chunyuan; Yang, Boyue; Zhu, Yu; Yang, Yanjun; Wang, Lianhui

    2017-01-15

    With years of outrageous mercury emissions, there is an urgent need to develop convenient and sensitive methods for detecting mercury ions in response to increasingly serious mercury pollution in water. In the present work, a portable, ultrasensitive SERS sensor is proposed and utilized for detecting trace mercury ions in water. The SERS sensor is prepared on an excellent sliver nanorods array SERS substrate by immobilizing T-component oligonucleotide probes labeled with dye on the 3'-end and -SH on the 5'-end. The SERS sensor responses to the specific chemical bonding between thymine and mercury ions, which causes the previous flexible single strand of oligonucleotide probe changing into rigid and upright double chain structure. Such change in the structure drives the dyes far away from the excellent SERS substrate and results in a SERS signal attenuation of the dye. Therefore, by monitoring the decay of SERS signal of the dye, mercury ions in water can be detected qualitatively and quantitatively. The experimental results indicate that the proposed optimal SERS sensor owns a linear response with wide detecting range from 1pM to 1μM, and a detection limit of 0.16pM is obtained. In addition, the SERS sensor demonstrates good specificity for Hg(2+), which can accurately identify trace mercury ions from a mixture of ten kinds of other ions. The SERS sensor has been further executed to analyze the trace mercury ions in tap water and lake water respectively, and good recovery rates are obtained for sensing both kinds of water. With its high selectivity and good portability, the ultrasensitive SERS sensor is expected to be a promising candidate for discriminating mercury ions in the fields of environmental monitoring and food safety.

  7. SER MUJER Y SER HOMBRE SEGÚN ALGUNAS MUJERES Y ALGUNOS VARONES SENTENCIADOS POR HOMICIDIO

    Directory of Open Access Journals (Sweden)

    MARITEL YANES

    2016-07-01

    Full Text Available Mediante el uso de los métodos cualitativos, se aplicó un guión temático sobre las opiniones de ser mujer y ser hombre de un grupo de mujeres y varones sentenciados por homicidio recluidos en el Centro de Reinserción del Estado de Tabasco (CRESET. Se buscaba conocer en qué medida sus concepciones de género influenciaron en su comportamiento homicida y observar cuales eran las principales diferencias. Se presentan los resultados del análisis de las respuestas al guion temático de las entrevistas realizadas, donde se observa el criterio de selección y el primer contacto con los entrevistados (as, las condiciones en que se llevaron a cabo las entrevistas, los objetivos y las categorías que se utilizaron para la elaboración del guion. Posteriormente, se describen y comparan las opiniones de las mujeres y de los hombres entrevistados sobre las categorías del guion temático que permiten apreciar múltiples elementos desde la perspectiva de género.

  8. Myofilament Calcium Sensitivity: Mechanistic Insight into TnI Ser-23/24 and Ser-150 Phosphorylation Integration

    Directory of Open Access Journals (Sweden)

    Hussam E Salhi

    2016-12-01

    Full Text Available Troponin I (TnI is a major regulator of cardiac muscle contraction and relaxation. During physiological and pathological stress, TnI is differentially phosphorylated at multiple residues through different signaling pathways to match cardiac function to demand. The combination of these TnI phosphorylations can exhibit an expected or unexpected functional integration, whereby the function of two phosphorylations are different than that predicted from the combined function of each individual phosphorylation alone. We have shown that TnI Ser-23/24 and Ser-150 phosphorylation exhibit functional integration and are simultaneously increased in response to cardiac stress. In the current study, we investigated the functional integration of TnI Ser-23/24 and Ser-150 to alter cardiac contraction. We hypothesized that Ser-23/24 and Ser-150 phosphorylation each utilize distinct molecular mechanisms to alter the TnI binding affinity within the thin filament. Mathematical modeling predicts that Ser-23/24 and Ser-150 phosphorylation affect different TnI affinities within the thin filament to distinctly alter the Ca2+-binding properties of troponin. Protein binding experiments validate this assertion by demonstrating pseudo-phosphorylated Ser-150 decreases the affinity of isolated TnI for actin, whereas Ser-23/24 pseudo-phosphorylation is not different from unphosphorylated. Thus, our data supports that TnI Ser-23/24 affects TnI-TnC binding, while Ser-150 phosphorylation alters TnI-actin binding. By measuring force development in troponin-exchanged skinned myocytes, we demonstrate that the Ca2+ sensitivity of force is directly related to the amount of phosphate present on TnI. Furthermore, we demonstrate that Ser-150 pseudo-phosphorylation blunts Ser-23/24-mediated decreased Ca2+-sensitive force development whether on the same or different TnI molecule. Therefore, TnI phosphorylations can integrate across troponins along the myofilament. These data demonstrate

  9. QUE É O "SER DA FAMÍLIA"?

    Directory of Open Access Journals (Sweden)

    Josefa Aida Delgado

    2005-01-01

    Full Text Available Es un estudio basado en la filosofía fenomenológica heideggeriana, su propósito es desvelar los elementos estructurales de la existencia del "ser de la familia". El camino metodológico fue construido con base en el pensamiento de Heidegger. Los datos de la familia fueron recolectados por medio de las entrevistas y las observaciones. Cada uno de nosotros contribuye para su existencia, y ella posibilita el desarrollo de nuestro "ser-en el-mundo" al vivenciar y compartir experiencias cotidianas de la familia. Allí surge la posibilidad de compartir un modo de ser en el mundo, un modo de cuidado para "ser familia en el mundo". Un mundo que genera esa unidad de relacionamiento que emerge de sentimientos interligados entre los integrantes, respondiendo a las exigencias de cada miembro, por el sentimiento de pertenencia primaria generado en ellos. Esa unidad da la posibilidad de nacer a cada uno de nosotros, asi también, nos da la posibilidad de poder ser ser humano, llegando a ser un referencial de sí misma en cada ser humano.

  10. Fundamentals and applications of SERS-based bioanalytical sensing

    Science.gov (United States)

    Kahraman, Mehmet; Mullen, Emma R.; Korkmaz, Aysun; Wachsmann-Hogiu, Sebastian

    2017-08-01

    Plasmonics is an emerging field that examines the interaction between light and metallic nanostructures at the metal-dielectric interface. Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that uses plasmonics to obtain detailed chemical information of molecules or molecular assemblies adsorbed or attached to nanostructured metallic surfaces. For bioanalytical applications, these surfaces are engineered to optimize for high enhancement factors and molecular specificity. In this review we focus on the fabrication of SERS substrates and their use for bioanalytical applications. We review the fundamental mechanisms of SERS and parameters governing SERS enhancement. We also discuss developments in the field of novel SERS substrates. This includes the use of different materials, sizes, shapes, and architectures to achieve high sensitivity and specificity as well as tunability or flexibility. Different fundamental approaches are discussed, such as label-free and functional assays. In addition, we highlight recent relevant advances for bioanalytical SERS applied to small molecules, proteins, DNA, and biologically relevant nanoparticles. Subsequently, we discuss the importance of data analysis and signal detection schemes to achieve smaller instruments with low cost for SERS-based point-of-care technology developments. Finally, we review the main advantages and challenges of SERS-based biosensing and provide a brief outlook.

  11. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    Institute of Scientific and Technical Information of China (English)

    XIE Zhi-Guo; LU Yong-Hua; WANG Pei; LIN Kai-Qun; YAN Jie; MING Hai

    2008-01-01

    @@ A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid.Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome maes-transport constraints, allowing more silver nanoparticles involved in SERS activity.This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture.We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA ) molecules with the injecting way and the common dipping measurement.The injecting way shows obviously better results than the dipping one.Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area.

  12. SERS decoding of micro gold shells moving in microfluidic systems.

    Science.gov (United States)

    Lee, Saram; Joo, Segyeong; Park, Sejin; Kim, Soyoun; Kim, Hee Chan; Chung, Taek Dong

    2010-05-01

    In this study, in situ surface-enhanced Raman scattering (SERS) decoding was demonstrated in microfluidic chips using novel thin micro gold shells modified with Raman tags. The micro gold shells were fabricated using electroless gold plating on PMMA beads with diameter of 15 microm. These shells were sophisticatedly optimized to produce the maximum SERS intensity, which minimized the exposure time for quick and safe decoding. The shell surfaces produced well-defined SERS spectra even at an extremely short exposure time, 1 ms, for a single micro gold shell combined with Raman tags such as 2-naphthalenethiol and benzenethiol. The consecutive SERS spectra from a variety of combinations of Raman tags were successfully acquired from the micro gold shells moving in 25 microm deep and 75 microm wide channels on a glass microfluidic chip. The proposed functionalized micro gold shells exhibited the potential of an on-chip microfluidic SERS decoding strategy for micro suspension array.

  13. Evaluation of SERS substrates for chemical agent detection

    Science.gov (United States)

    Huang, Hermes; Shende, Chetan; Sengupta, Atanu; Inscore, Frank; Farquharson, Stuart

    2012-06-01

    US Military forces are dependent on indigenous water supplies, which are considered prime targets to effect a chemical or biological attack. Consequently, there is a clear need for a portable analyzer capable of evaluating water supplies prior to use. To this end we have been investigating the use of a portable Raman analyzer with surface-enhanced Raman spectroscopy (SERS) sampling systems. The superior selectivity and exceptional sensitivity of SERS has been demonstrated by the detection of single molecules. However, the extreme sensitivity provided by SERS is attributed to "hot spot" structures, such as particle junctions that can provide as much as 10 orders of magnitude enhancement. Unfortunately, hotspots are not evenly distributed across substrates, which results in enhancements that cannot be quantitatively reproduced. Here we present analysis of uniformity for a newly developed substrate and commercial sample vials using benzenethiol and bispyridylethylene, two chemicals often used to characterize SERS substrates, and methyl phosphonic acid, a major hydrolysis product of the nerve agents.

  14. Development of a SERS aptasensor for detection of medical residues

    DEFF Research Database (Denmark)

    Frøhling, Kasper Bayer

    of stringency successful detection was never accomplished. In conclusion, this PhD project successfully characterised the chemical functionalisation parameters needed for generic SERS aptasensor development using only the Raman signals of the molecules. The SERS substrate was successfully fabricated repeatedly......Low levels of medical residues in environmental, industrial and domestic water systems is a growing concern. The biosensor industry is trying to accomodate the need of sensitive and specific sensor systems capable of ultra-low level detection of medical residues. In this PhD project a surface...... enhanced Raman spectroscopy (SERS) sensor for the female sexhormone 17β-estradiol was attempted. It is commonly used in contraceptive pills from where it find its way through waste water treatment plants and into the environment. The SERS substrate was fabricated in a cleanroom facility using techniques...

  15. SERS diagnostic platforms, methods and systems microarrays, biosensors and biochips

    Energy Technology Data Exchange (ETDEWEB)

    Vo-Dinh, Tuan (Knoxville, TN)

    2007-09-11

    A Raman integrated sensor system for the detection of targets including biotargets includes at least one sampling platform, at least one receptor probe disposed on the sampling platform, and an integrated circuit detector system communicably connected to the receptor. The sampling platform is preferably a Raman active surface-enhanced scattering (SERS) platform, wherein the Raman sensor is a SERS sensor. The receptors can include at least one protein receptor and at least one nucleic acid receptor.

  16. SERS diagnostic platforms, methods and systems microarrays, biosensors and biochips

    Science.gov (United States)

    Vo-Dinh, Tuan

    2007-09-11

    A Raman integrated sensor system for the detection of targets including biotargets includes at least one sampling platform, at least one receptor probe disposed on the sampling platform, and an integrated circuit detector system communicably connected to the receptor. The sampling platform is preferably a Raman active surface-enhanced scattering (SERS) platform, wherein the Raman sensor is a SERS sensor. The receptors can include at least one protein receptor and at least one nucleic acid receptor.

  17. SERS biodetection using gold-silica nanoshells and nitrocellulose membranes.

    Science.gov (United States)

    Bishnoi, Sandra Whaley; Lin, Yu-jen; Tibudan, Martin; Huang, Yiming; Nakaema, Marcelo; Swarup, Vimal; Keiderling, Timothy A

    2011-06-01

    We have developed a rapid, reproducible, easy to execute, surface enhanced Raman scattering (SERS) method for detection of low volumes and total amounts of biological antigens using an analyte capture system derived from methods commonly used in Western blotting. Our method is a "half-sandwich" assay with an antigen detection scheme that employs a nitrocellulose (NC) membrane with 200 nm pore size to capture subnanograms of analyte and concentrate them in a small area from applied volumes as low as one microliter. The SERS probes used for detection consist of gold-silica nanoshells modified with a two-component mixed monolayer system. One component consists of a poly(ethylene glycol) (PEG)-modified Raman-active chromophore bound to the gold surface which allows for SERS detection and imparts particle stability. The second component uses (ortho-pyridyl) disulfide-PEG-succinimidyl ester to couple the recognition antibody to the particle surface. By controlling the reaction time and concentration of thiols, a mixed monolayer is prepared on the nanoshell surface with the ability to recognize low concentrations of analyte and generate reproducible SERS signals. Using this strategy, we have achieved SERS signals that are proportional to antigen present on the membrane allowing detection of total antigen amounts as low as 1.25 ng for some cases. The performance of this new SERS bioassay has been tested with a variety of potential antigens, demonstrating the potential for multiplexed detection of analytes.

  18. Superhydrophobic Ag nanostructures on polyaniline membranes with strong SERS enhancement.

    Science.gov (United States)

    Liu, Weiyu; Miao, Peng; Xiong, Lu; Du, Yunchen; Han, Xijiang; Xu, Ping

    2014-11-07

    We demonstrate here a facile fabrication of n-dodecyl mercaptan-modified superhydrophobic Ag nanostructures on polyaniline membranes for molecular detection based on SERS technique, which combines the superhydrophobic condensation effect and the high enhancement factor. It is calculated that the as-fabricated superhydrophobic substrate can exhibit a 21-fold stronger molecular condensation, and thus further amplifies the SERS signal to achieve more sensitive detection. The detection limit of the target molecule, methylene blue (MB), on this superhydrophobic substrate can be 1 order of magnitude higher than that on the hydrophilic substrate. With high reproducibility, the feasibility of using this SERS-active superhydrophobic substrate for quantitative molecular detection is explored. A partial least squares (PLS) model was established for the quantification of MB by SERS, with correlation coefficient R(2) = 95.1% and root-mean-squared error of prediction (RMSEP) = 0.226. We believe this superhydrophobic SERS substrate can be widely used in trace analysis due to its facile fabrication, high signal reproducibility and promising SERS performance.

  19. Surface enhanced Raman scattering (SERS) fabrics for trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Zhou, Ji [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Tang, Bin, E-mail: bin.tang@deakin.edu.au [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia); Zeng, Tian; Li, Yaling [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Li, Jingliang [Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia); Ye, Yong, E-mail: yeyong@hubu.edu.cn [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Ministry of Education & College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Wang, Xungai [National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Wuhan Textile University, Wuhan 430073 (China); Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216 (Australia)

    2016-11-15

    Highlights: • Gold nanoparticles are in-situ synthesized on silk fabrics by heating. • Flexible silk fabrics with gold nanoparticles are used for surface-enhanced Raman scattering (SERS). • SERS activities of silk fabrics with different gold contents are investigated. - Abstract: Flexible SERS active substrates were prepared by modification of silk fabrics with gold nanoparticles. Gold nanoparticles were in-situ synthesized after heating the silk fabrics immersed in gold ion solution. Localized surface plasmon resonance (LSPR) properties of the treated silk fabrics varied as the concentration of gold ions changed, in relation to the morphologies of gold nanoparticles on silk. In addition, X-ray diffraction (XRD) was used to observe the structure of the gold nanoparticle treated silk fabrics. The SERS enhancement effect of the silk fabrics treated with gold nanoparticles was evaluated by collecting Raman signals of different concentrations of p-aminothiophenol (PATP), 4-mercaptopyridine (4-MPy) and crystal violet (CV) solutions. The results demonstrate that the silk fabrics corresponding to 0.3 and 0.4 mM of gold ions possess high SERS activity compared to the other treated fabrics. It is suggested that both the gold content and morphologies of gold nanoparticles dominate the SERS effect of the treated silk fabrics.

  20. Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

    Directory of Open Access Journals (Sweden)

    Oana-M. Buja

    2017-01-01

    Full Text Available A microfluidic setup which enables on-line monitoring of residues of malachite green (MG using surface-enhanced Raman scattering (SERS is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

  1. SERS-based application in food analytics (Conference Presentation)

    Science.gov (United States)

    Cialla-May, Dana; Radu, Andreea; Jahn, Martin; Weber, Karina; Popp, Jürgen

    2017-02-01

    To establish detection schemes in life science applications, specific and sensitive methods allowing for fast detection times are required. Due to the interaction of molecules with strong electromagnetic fields excited at metallic nanostructures, the molecular fingerprint specific Raman spectrum is increased by several orders of magnitude. This effect is described as surface-enhanced Raman spectroscopy (SERS) and became a very powerful analytical tool in many fields of application. Within this presentation, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer. To do so, the food colorant Sudan III, an indirect carcinogen substance found in chili powder, palm oil or spice mixtures, is detected quantitatively in the background of the competitor riboflavin as well as paprika powder extracts. The SERS-based detection of azorubine (E122) in commercial available beverages with different complexity (e.g. sugar content, alcohol concentration) illustrates the strong potential of SERS as a qualitative as well as semiquantitative prescan method in food analytics. Here, a good agreement between the estimated concentration employing SERS as well as the gold standard technique HPLC, a highly laborious method, is found. Finally, SERS is applied to detect vitamin B2 and B12 in cereals as well as the estimate the ratio of lycopene and β-carotene in tomatoes. Acknowledgement: Funding the projects "QuantiSERS" and "Jenaer Biochip Initiative 2.0" within the framework "InnoProfile Transfer - Unternehmen Region" the Federal Ministry of Education and Research, Germany (BMBF) is gratefully acknowledged.

  2. SERS substrates for in-situ biosensing (Conference Presentation)

    Science.gov (United States)

    Venugopalan, Priyamvada; Quilis, Nestor; Jakub, Dostalek; Wolfgang, Knoll

    2017-06-01

    Abstract: Recent years have seen a rapid progress in the field of surface-enhanced Raman spectroscopy (SERS) which is attributed to the thriving field of plasmonics [1]. SERS is a susceptible technique that can address basic scientific questions and technological problems. In both cases, it is highly dependent upon the plasmonic substrate, where excitation of the localized surface plasmon resonance enhances the vibrational scattering signal of the analyte molecules adsorbed on to the surface [2]. In this work, using finite difference time domain (FDTD) method we investigate the optical properties of plasmonic nanostructures with tuned plasmonic resonances as a function of dielectric environment and geometric parameters. An optimized geometry will be discussed based on the plasmonic resonant position and the SERS intensity. These SERS substrates will be employed for the detection of changes in conformation caused by interactions between an aptamer and analyte molecules. This will be done by using a microfluidic channel designed within the configuration of the lab-on-a-chip concept based on the intensity changes of the SERS signal. More efficient and reproducible results are obtained for such a quantitative measurement of analytes at low concentration levels. We will also demonstrate that the plasmonic substrates fabricated by top down approach such as e-beam lithography (EBL) and laser interference lithography (LIL) are highly reproducible, robust and can result in high electric field enhancement. Our results demonstrate the potential to use SERS substrates for highly sensitive detection schemes opening up the window for a wide range of applications including biomedical diagnostics, forensic investigation etc. Acknowledgement: This work was supported by the Austrian Science Fund (FWF), project NANOBIOSENSOR (I 2647). References: [1] J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao and R. P. V. Duyne., " Biosensing with plasmonic nanosensors," Nature

  3. Large area flexible SERS active substrates using engineered nanostructures

    Science.gov (United States)

    Chung, Aram J.; Huh, Yun Suk; Erickson, David

    2011-07-01

    Surface enhanced Raman scattering (SERS) is an analytical sensing method that provides label-free detection, molecularly specific information, and extremely high sensitivity. The Raman enhancement that makes this method attractive is mainly attributed to the local amplification of the incident electromagnetic field that occurs when a surface plasmon mode is excited at a metallic nanostructure. Here, we present a simple, cost effective method for creating flexible, large area SERS-active substrates using a new technique we call shadow mask assisted evaporation (SMAE). The advantage of large, flexible SERS substrates such as these is they have more area for multiplexing and can be incorporated into irregular surfaces such as clothing. We demonstrate the formation of four different types of nanostructure arrays (pillar, nib, ellipsoidal cylinder, and triangular tip) by controlling the evaporation angle, substrate rotation, and deposition rate of metals onto anodized alumina nanoporous membranes as large as 27 mm. In addition, we present experimental results showing how a hybrid structure comprising of gold nanospheres embedded in a silver nano-pillar structure can be used to obtain a 50× SERS enhancement over the raw nanoparticles themselves.Surface enhanced Raman scattering (SERS) is an analytical sensing method that provides label-free detection, molecularly specific information, and extremely high sensitivity. The Raman enhancement that makes this method attractive is mainly attributed to the local amplification of the incident electromagnetic field that occurs when a surface plasmon mode is excited at a metallic nanostructure. Here, we present a simple, cost effective method for creating flexible, large area SERS-active substrates using a new technique we call shadow mask assisted evaporation (SMAE). The advantage of large, flexible SERS substrates such as these is they have more area for multiplexing and can be incorporated into irregular surfaces such as

  4. Gold nanoparticles paper as a SERS bio-diagnostic platform.

    Science.gov (United States)

    Ngo, Ying Hui; Then, Whui Lyn; Shen, Wei; Garnier, Gil

    2013-11-01

    Bioactive papers are usually challenged by four major limitations: sensitivity, selectivity, simplicity and strength (4S). Gold nanoparticles (AuNPs) treated paper has previously been demonstrated as a Surface Enhanced Raman Scattering (SERS) active substrate, capable of addressing the 4S issues. In this study, AuNPs on paper substrate were functionalized by a series of biomolecules to develop a generic SERS platform for antibody-antigen detection. The functionalization steps were performed by taking advantage of the high affinity association between Streptomyces avidinii-derived protein, streptavidin, and biotin. Streptavidin was firstly bound onto the AuNPs treated paper using biotinylated-thiol. Subsequently, desired biotinylated-antibody was bound onto the streptavidin. SERS spectra of each functionalization step were obtained to ensure specific adsorption of the bio-molecules. The binding interaction of the antibody with its specific antigen was detected using SERS. Shifts of Raman band associated with α-helix and β-sheet structures indicated structural modification of the antibody upon interaction with its antigen. Predominant tryptophan and tyrosine residue bands were also detected, confirming the presence of antigen. Reproducible spectral features were quantified as AuNP papers were subjected to different concentrations of antigen; the spectra intensity increased as a function of the antigen concentration. The retention of AuNPs on paper remained constant after all the consecutive washing and functionalization steps. The feasibility of AuNPs paper as a low-cost and generic SERS platform for bio-diagnostic applications was demonstrated.

  5. Super-SERS-active and highly effective antimicrobial Ag nanodendrites

    Science.gov (United States)

    Li, H. B.; Liu, P.; Liang, Y.; Xiao, J.; Yang, G. W.

    2012-07-01

    We have developed simple and green electrochemistry to synthesize Ag nanostructures with high purity, good crystallinity and smooth surface for applications as super-SERS (surface-enhanced Raman scattering), SERS-active substrates and with highly effective antimicrobial activities. This synthesis takes place in a clean and slow reaction environment without any chemical additives, which ensures an ultrahigh active surface of the as-synthesized Ag nanostructures owing to their purity, good crystallinity and smooth morphology. Using this method, we synthesized nearly perfect Ag nanodendrites (NDs), which exhibit super-SERS sensitivity when they are used to detect the SERS spectra of rhodamine 6G at concentrations as low as 5 × 10-16 M, and have an ultrahigh electromagnetic (EM) enhancement factor of the order of 1013, breaking through the theoretical limit of EM enhancement. Meanwhile, the as-synthesized Ag NDs possess highly effective antimicrobial activities for Escherichia coli, Candida albicans and Staphylococcus aureus, which are over 10 times that of silver nanoparticles. Additionally, the basic physics and chemistry involved in the fabrication of Ag nanostructures are pursued. These investigations show that silver nanostructures with highly active surfaces can make the most of Ag nanostructures functioning as super-SERS-active substrates and multiple antibiotics.

  6. LA GENÉTICA Y LA DIGNIDAD DEL SER HUMANO

    Directory of Open Access Journals (Sweden)

    Nicolás Jouve de Barreda

    2013-01-01

    Full Text Available Los elementos biológicos del hombre no son suficientes para afrontar las cuestiones bioéticas que se plantean en torno al concepto de persona, pero son necesarios para definir con precisión las propiedades de los seres humanos y los aspectos teológicos, filosóficos y jurídicos que son atribuibles a cada persona. El ser humano es un ser singular. En él que conviven dos dimensiones de distinta naturaleza, una material y otra espiritual, y precisamente esta es la principal de las diferencias entre el hombre y el resto de seres vivos. Pero además en el hombre aparece una nueva característica, única entre los seres vivos, la componente ética. Los valores y pautas del comportamiento moral y ético del ser humano deben considerarse de origen natural ya que han contribuido al éxito y supervivencia de la especie. El hombre no es solo Homo sapiens sino también Homo moralis. El reconocimiento de culpa, autodominio, solidaridad, amor, generosidad, altruismo y honestidad, entre otras, son cualidades innatas en los seres humanos. La antropología filosófica destaca el carácter único e irrepetible propio de cada ser humano, cada persona. Esto coincide plenamente con los datos de la ciencia, que destaca la identidad genética individual y singular de cada ser humano.

  7. Normal Raman and SERS spectroscopy of the vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Cai Tiantian; Gu Huaimin; Yuan Xiaojuan; Liu Fangfang, E-mail: guhm@scnu.edu.cn [MOE Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, 510631, Guangzhou (China)

    2011-01-01

    In this study, surface-enhanced Raman scattering(SERS)spectra of vitamin E were obtained on colloidal silver(Ag). Alpha-(-) tocopherol which is the only form that is recognized to meet human requirements was selected to study. The analytes ({+-})- -tocopherol were dissolved in chloroform (CHCl{sub 3}) and the silver colloid was poured into the compound. Silver colloid was reduced by hydroxylamine hydrochloride. The analytes were the supernatant after standing the mixture for the reason that chloroform have no signals in surface-enhanced Raman scattering in the Ag colloid, and it would not affect the determination of the ({+-})- -tocopherol. The Normal Raman and SERS spectrum of Vitamin E were contrastively studied to realize how the vitamin E stuck to the silver nanoparticles. The results show the fat-soluble substances can be analysed by SERS. The spectra indicate that the molecules are adsorbed on the surface through the COO- groups by the simultaneous involvement of a and -type coordination. These results suggest some important criteria for consideration in SERS measurements and also provide important insights into the problem of predicting SERS activities for different fat-soluble substances.

  8. Combined SPR and SERS: Otto and Kretschmann configurations

    Science.gov (United States)

    Barchiesi, Dominique; Grosges, Thomas; Colas, Florent; Lamy de la Chapelle, Marc

    2015-11-01

    Combined surface enhanced Raman spectroscopy (SERS) and surface plasmon resonance (SPR) setup was proposed recently. The experimental setup requires a gold layer deposited on a glass substrate. However, due to the poor ability of sticking gold material on glass, a nanometric adhesion layer is used. In this paper we compare numerically both the SERS gain, and the SPR signal, for metallic and dielectric adhesion layers, for two substrates. We show that even if the dielectric materials can be considered as equivalent for the SPR signal, this is not the case for the SERS gain. In particular the dielectric adhesion layer reduces the sensitivity of the SERS gain to this parameter and therefore their use could be more suitable for the fabrication of the sensor. Moreover the higher the refractive index of substrate with regards to the adhesion layer is, the higher efficiency of setup is obtained, and therefore the Otto configuration seems to be more efficient than the Kretschmann one. Optimization of the thicknesses of the adhesion layer and of the gold layer can lead to a SERS gain greater than 103 without nanostructuring.

  9. PromoSer: improvements to the algorithm, visualization and accessibility.

    Science.gov (United States)

    Halees, Anason S; Weng, Zhiping

    2004-07-01

    PromoSer is a web service that provides an easy and efficient approach to the batch retrieval of a large number of proximal promoters. Since its introduction last year, it has undergone continued development and expansion. At the core, there have been improvements in the filtering of the raw mRNA/EST sequences upon which all predictions are built, improvements in the alignments clustering and transcription start site prediction algorithms, and improvements in the backing database for increased performance. At the user interface level, improvements include enhanced functionality and user options, better integration with other resources on the web and a new visualization tool. PromoSer now also supports queries using a SOAP-based interface and XML-based responses. The service is publicly available at http://biowulf.bu.edu/zlab/PromoSer.

  10. ser en otorrinolaringología

    OpenAIRE

    Castillo F,Marcela; Lanas V,Andrés

    2006-01-01

    Esta revisión bibliográfica analiza los diferentes tipos de láser usados en otorrinolaringología, destacando las propiedades de cada uno. Posteriormente describe las características de una sesión con anestesia y uso de láser y las patologías con indicaciones de cirugía láser. Estas se clasifican en cinco rubros. Patología laringotraqueal, patología faringobucal, patología sinusal, otología y dermatología cérvico facial. En la primera se analizan: lesiones fonoquirúrgico, papilomatosis larínge...

  11. LA ÍNDOLE TECNOLÓGICA DEL SER HUMANO

    Directory of Open Access Journals (Sweden)

    José Luis del Barco Collazos

    2009-01-01

    Full Text Available La técnica no es accidental, sino esencial, al ser humano. Es el modo de vida del homo sapiens sapiens. No ha habido vida humana pretecnológica ni un periodo de la historia sin ella. Desde que el hombre puso los pies sobre la tierra empezó a fabricar instrumentos. Y seguirá fabricándolos. El arado, la aeronave y los ingenios técnicos del futuro son fases del progreso técnico. La asombrosa capacidad humana para fabricar se debe a la conexión entre las manos y el cerebro. La técnica no debe ser objeto de reverencia ni de temor pero sí debe ser gobernada.

  12. ser en otorrinolaringología

    OpenAIRE

    Castillo F,Marcela; Lanas V,Andrés

    2006-01-01

    Esta revisión bibliográfica analiza los diferentes tipos de láser usados en otorrinolaringología, destacando las propiedades de cada uno. Posteriormente describe las características de una sesión con anestesia y uso de láser y las patologías con indicaciones de cirugía láser. Estas se clasifican en cinco rubros. Patología laringotraqueal, patología faringobucal, patología sinusal, otología y dermatología cérvico facial. En la primera se analizan: lesiones fonoquirúrgico, papilomatosis larínge...

  13. SER Y ESTAR CON ADJETIVOS – SIGNIFICACION DE LAS PROPOSICIONES SER Y ESTAR CON ADJETIVOS – SIGNIFICACION DE LAS PROPOSICIONES

    Directory of Open Access Journals (Sweden)

    Javier García de María

    2008-07-01

    Full Text Available Ser y estar: uno de los temas difíciles de la enseñanza/aprendizaje del español. Este trabajo expone un enfoque que recurre a la significación como hilo conductor. Por una parte, a la significación de ser y de estar como verbos, en sí mismos. Por otra, a la significación de los adjetivos. El planteamiento no es ya qué significa un determinado adjetivo con ser o con estar, sino cuál de estos verbos puede expresar su significado único o cada uno de sus significados. Sobre esta base el análisis considera, primero, los significados de ser/estar y los significados de un adjetivo dado y, segundo, los resultados significativos que arroja la relación entre verbos y adjetivo. Cuando el significado de un adjetivo se pueda expresar con los dos verbos, la elección vendrá determinada por la intencionalidad del hablante en el contexto comunicativo en que se encuentre. A partir de aquí las construcciones en las que aparecen ser y estar son tratadas como proposiciones retórico-argumentativas.Ser and estar: a difficult aspect of Spanish as a foreign language. This essay presents an approach that takes signification as guide line. On the one hand, the signification of ser and estar for their own cause; on the other hand the signification of the adjectives. The question is no longer what the meaning of a given adjective is with ser or with estar, but with which of the two verbs is it possible to express the unique meaning or each of the meanings of that adjective. Starting from this basis the approach considers first, the isolated meanings of the verbs and of the adjectives and, second, the resultant signification out of the relation between the two sides. If the meaning of a given adjective can be expressed by both verbs, the selection of the verb is determined by the intentionality of the speaker in the communicative context in which he negotiates. From this background on the syntactical constructions in which ser and estar appear are treated as

  14. Ciprofloxacin: pH-dependent SERS signal and its detection in spiked river water using LoC-SERS.

    Science.gov (United States)

    Hidi, Izabella J; Heidler, Jan; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2016-11-01

    Monitoring the successful removal of antibiotics in waste and surface waters is of high interest to overcome the occurrence of antibacterial resistance in the ecosystem. Among the newly developed analytical methods, the lab-on-a-chip surface-enhanced Raman spectroscopic (LoC-SERS) technique has gained the interest of the scientific community in the last few years. Ciprofloxacin, a second-generation fluoroquinolone, is widely used and administered to patients in dosages up to 1000 mg. In addition, more than 50 % of the antibiotic is excreted in urine as the parental drug. Thus, ciprofloxacin in environmental samples may exceed the minimum inhibitory concentration (MIC) values. The present study aims to assess the potential of the LoC-SERS technique to detect the target analyte in spiked river water samples at MIC concentrations. As sample clean-up procedure, a simple filtration is proposed, while as SERS, active substrates silver nanoparticles prepared at room temperature are employed. Ciprofloxacin was successfully quantified in the 0.7-10 μM concentration range with data that were measured on two different days. Furthermore, because of the low solubility of the antibiotic at the neutral pH range, insights into the effect of pH on the SERS signal of the target molecule are also presented. Graphical Abstract Ciprofloxacin detected at MIC values by LOC-SERS.

  15. New nanocomposites for SERS studies of living cells and mitochondria

    DEFF Research Database (Denmark)

    Sarycheva, A. S.; Brazhe, N. A.; Baizhumanov, A. A.

    2016-01-01

    molecules. The SERS spectra of functional mitochondria are sensitive to the activity of the mitochondrial electron transport chain, thus making the method a novel label-free approach to monitor the redox state and conformation of cytochromes in their natural cell environment. The developed nanocomposites......A great enhancement in Raman scattering (SERS) from heme-containing submembrane biomolecules inside intact erythrocytes and functional mitochondria is demonstrated for the first time using silver–silica beads prepared using a new method involving aerosol pyrolysis with aqueous diamminesilver...

  16. Sers-Active Silver Nanoparticles in Ion-Exchanged Glass

    Science.gov (United States)

    Chen, Ya; Jaakola, Janne; Säynätjoki, Antti; Tervonen, Ari; Honkanen, Seppo

    We study synthesis and SERS activity of glass-embedded ion-exchanged silver nanoparticles formed by two different methods. Silver-sodium ion-exchange process with heat treatment was utilized on commercial microscope slides, while masked ion-exchange technique was performed on glass Corning 0211. The distribution of particles was studied by absorption spectroscopy and atomic force microscopy. After etching the glass surface to expose the particles, SERS performance of these particles was investigated with micro-Raman spectroscopy using Rhodamine 6G as the analyte.

  17. Phosphorylation on Ser-279 and Ser-282 of connexin43 regulates endocytosis and gap junction assembly in pancreatic cancer cells

    Science.gov (United States)

    Johnson, Kristen E.; Mitra, Shalini; Katoch, Parul; Kelsey, Linda S.; Johnson, Keith R.; Mehta, Parmender P.

    2013-01-01

    The molecular mechanisms regulating the assembly of connexins (Cxs) into gap junctions are poorly understood. Using human pancreatic tumor cell lines BxPC3 and Capan-1, which express Cx26 and Cx43, we show that, upon arrival at the cell surface, the assembly of Cx43 is impaired. Connexin43 fails to assemble, because it is internalized by clathrin-mediated endocytosis. Assembly is restored upon expressing a sorting-motif mutant of Cx43, which does not interact with the AP2 complex, and by expressing mutants that cannot be phosphorylated on Ser-279 and Ser-282. The mutants restore assembly by preventing clathrin-mediated endocytosis of Cx43. Our results also document that the sorting-motif mutant is assembled into gap junctions in cells in which the expression of endogenous Cx43 has been knocked down. Remarkably, Cx43 mutants that cannot be phosphorylated on Ser-279 or Ser-282 are assembled into gap junctions only when connexons are composed of Cx43 forms that can be phosphorylated on these serines and forms in which phosphorylation on these serines is abolished. Based on the subcellular fate of Cx43 in single and contacting cells, our results document that the endocytic itinerary of Cx43 is altered upon cell–cell contact, which causes Cx43 to traffic by EEA1-negative endosomes en route to lysosomes. Our results further show that gap-junctional plaques formed of a sorting motif–deficient mutant of Cx43, which is unable to be internalized by the clathrin-mediated pathway, are predominantly endocytosed in the form of annular junctions. Thus the differential phosphorylation of Cx43 on Ser-279 and Ser-282 is fine-tuned to control Cx43’s endocytosis and assembly into gap junctions. PMID:23363606

  18. Au-ZnO hybrid nanoparticles exhibiting strong charge-transfer-induced SERS for recyclable SERS-active substrates

    Science.gov (United States)

    Liu, Liping; Yang, Haitao; Ren, Xiao; Tang, Jin; Li, Yongfeng; Zhang, Xiangqun; Cheng, Zhaohua

    2015-03-01

    Flower-shaped Au-ZnO hybrid nanoparticles have been prepared via seeding growth and subsequent wet-chemical etching of Au-ZnO core-shell nanoparticles. The etched Au-ZnO hybrid nanoparticles have shown a stronger surface-enhanced Raman scattering (SERS) signal of the nontotally symmetric (b2) vibrational modes of PATP molecules than Au nanoparticles alone, which is attributed to the chemical enhancement effect of the ZnO layer which is greatly excited by the localized surface plasmon resonance (LSPR) of Au cores. Further, the mechanism of the LSPR-enhanced charge transfer (CT) effect has been proved by the SERS spectra of PATP molecules excited using different laser sources from 325 to 785 nm. Moreover, the photocatalytic experimental results indicated that Au-ZnO hybrid nanoparticles are promising as biologically compatible and recyclable SERS-active platforms for different molecular species.Flower-shaped Au-ZnO hybrid nanoparticles have been prepared via seeding growth and subsequent wet-chemical etching of Au-ZnO core-shell nanoparticles. The etched Au-ZnO hybrid nanoparticles have shown a stronger surface-enhanced Raman scattering (SERS) signal of the nontotally symmetric (b2) vibrational modes of PATP molecules than Au nanoparticles alone, which is attributed to the chemical enhancement effect of the ZnO layer which is greatly excited by the localized surface plasmon resonance (LSPR) of Au cores. Further, the mechanism of the LSPR-enhanced charge transfer (CT) effect has been proved by the SERS spectra of PATP molecules excited using different laser sources from 325 to 785 nm. Moreover, the photocatalytic experimental results indicated that Au-ZnO hybrid nanoparticles are promising as biologically compatible and recyclable SERS-active platforms for different molecular species. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00491h

  19. SERS internship fall 1995 abstracts and research papers

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Beverly

    1996-05-01

    This report is a compilation of twenty abstracts and their corresponding full papers of research projects done under the US Department of Energy Science and Engineering Research Semester (SERS) program. Papers cover a broad range of topics, for example, environmental transport, supercomputers, databases, biology. Selected papers were indexed separately for inclusion the the Energy Science and Technology Database.

  20. Analysis and differentiation of seminal plasma via polarized SERS spectroscopy

    Directory of Open Access Journals (Sweden)

    Chen X

    2012-12-01

    Full Text Available Xiwen Chen,1,* Zufang Huang,1,* Shangyuan Feng,1 Jinhua Chen,2 Lan Wang,1 Peng Lu,1 Haishan Zeng,3 Rong Chen1 1Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China; 2Fujian Provincial Hospital, Fuzhou, China; 3Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, BC, Canada*These authors contributed equally to this workAbstract: Polarized surface-enhanced Raman scattering (SERS spectroscopy was applied for obtaining biochemical information about the seminal plasma. The effect of different laser polarizations (nonpolarized, linear-polarized, right-handed circularly polarized, and left-handed circularly polarized on seminal plasma SERS spectroscopy was explored for the first time. The diagnostic performance in differentiating abnormal seminal plasma (n = 37 from normal seminal plasma (n = 24 was evaluated. A combination of principal component analysis (PCA and linear discriminant analysis (LDA was employed to develop diagnostic algorithms. Classification results of different laser polarizations demonstrated different diagnostic sensitivities and specificities, among which, left-handed circularly polarized laser excitation showed the best diagnostic result (95.8% sensitivity and 64.9% specificity. Our exploratory study demonstrated that SERS spectroscopy with left-handed circularly polarized laser excitation has the potential for becoming a new diagnostic method in semen-quality assessment.Keywords: SERS, seminal plasma, PCA-LDA, polarized laser excitation, silver nanoparticles, biomolecule chirality

  1. Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection.

    Science.gov (United States)

    Wang, Hsin-Neng; Fales, Andrew M; Vo-Dinh, Tuan

    2015-05-01

    Developing a simple and efficient nucleic acid detection technology is essential for clinical diagnostics. Here, we describe a new conceptually simple and selective "turn on" plasmonics-based nanobiosensor, which integrates non-enzymatic DNA strand-displacement hybridization for specific nucleic acid target identification with surface-enhanced Raman scattering (SERS) detection. This SERS nanobiosensor is a target label-free, and rapid nanoparticle-based biosensing system using a homogeneous assay format that offers a simple and efficient tool for nucleic acid diagnostics. Our results showed that the nanobiosensor provided a limit of detection of ~0.1nM (200amol) in the current bioassay system, and exhibited high specificity for single nucleotide mismatch discrimination. Surface-enhanced Raman scattering (SERS) is a sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. The enhancement means that the technique may even detect single molecules. In this article, the authors describe a simple and efficient nucleic acid detection technology using SERS, with "OFF-to-ON" signal switch upon nucleic acid target identification and capture, which provides high sensitivity and specificity for single nucleotide mismatch discrimination. This new technology will be most welcomed in clinical diagnostics. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. A Novel Substrate Used for Simultaneous SERS and RAIR

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel substrate, whose silver particles were deposited on both sides of a slide, was made by silver mirror reaction. Its two sides had different thinness and reflectivity and they were suited for the test of surface enhanced Raman spectroscopy (SERS) and reflection absorption infrared spectroscopy (RAIR) technique respectively.

  3. SERS activity of self-cleaning silver/titania nanoarray

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yibing, E-mail: ybxie@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China); Jin, Yanyan [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China); Zhou, Yingzhi; Wang, Yong [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China)

    2014-09-15

    Highlights: • Ag/TiO{sub 2} nanoarray is prepared by depositing Ag on TiO{sub 2} nanorod and nanotube array. • Ag/TiO{sub 2} nanoarray shows good SERS activity and self-cleaning performance as well. • Ag/TiO{sub 2} NRA as SERS substrate shows a low detection limit of PMBA below 5 × 10{sup −12} M. - Abstract: Silver decorated titania nanorod array (Ag/TiO{sub 2} NRA) and nanopore array (Ag/TiO{sub 2} NPA) had been designed as surface-enhanced Raman scattering (SERS) active substrate for a sensitive detection application. TiO{sub 2} NRA grown on glass slide was fabricated through hydrothermal synthesis process. TiO{sub 2} NPA grown on the titanium sheet was fabricated by a two-stepped anodization process. Ag/TiO{sub 2} NRA and Ag/TiO{sub 2} NPA were formed by depositing silver nanoparticles on TiO{sub 2} nanoarray through an electroless deposition process. Ag/TiO{sub 2} NRA had smaller silver interparticle gaps and more hot-spots than Ag/TiO{sub 2} NPA, exhibiting a higher SERS activity. The analytical enhancement factor was accordingly increased from 1.8 × 10{sup 5} for Ag/TiO{sub 2} NPA up to 7.8 × 10{sup 5} for Ag/TiO{sub 2} NRA. Ag/TiO{sub 2} NRA substrate achieved a very low detection limit of 5 × 10{sup −12} M 4-mercaptobenzoic acid as a probe molecule, showing a sensitive SERS detection performance. Ag/TiO{sub 2} NRA also conducted photocatalysis decomposition of these adsorbed organic molecules to recover a clean surface under UV irradiation, exhibiting a self-cleaning activity. Such an Ag/TiO{sub 2} nanoarray with well-controlled size and shape could be suitably applies as a self-cleaning SERS substrate, showing high reproducibility and cycleability in recycling SERS detection application.

  4. Black silicon SERS substrate: effect of surface morphology on SERS detection and application of single algal cell analysis.

    Science.gov (United States)

    Deng, Yu-Luen; Juang, Yi-Je

    2014-03-15

    In this study, we have investigated the effect of the surface morphology of the black silicon substrate on surface enhanced Raman spectroscopy (SERS) and explored its application of single algal cell detection. By adjusting the O2 and SF6 flow rates in the cryogenic plasma etching process, different surface morphologies of the black silicon substrate was produced without performing the lithographic process. It was found the Raman signals were better enhanced as the tip density of the black silicon substrate increased. In addition, as the thickness of the deposited gold layer increased, the SERS effect increased as well, which could be owing to the generation of more hot spots by bridging individual silicon tips through deposition of gold layer. For the black silicon substrate with tip density of 30 tips/μm(2) and covered by 400 nm deposited gold layer, the detection limit of 10 fM R6G solution concentration with uniform SERS effect across the substrate was achieved. Furthermore, detection of individual algal cell (Chlorella vulgaris) was performed at the SERS substrate as fabricated and the Raman signals of carotenoid and lipid were substantially enhanced.

  5. Processing ser and estar to locate objects and events

    Science.gov (United States)

    Dussias, Paola E.; Contemori, Carla; Román, Patricia

    2016-01-01

    In Spanish locative constructions, a different form of the copula is selected in relation to the semantic properties of the grammatical subject: sentences that locate objects require estar while those that locate events require ser (both translated in English as ‘to be’). In an ERP study, we examined whether second language (L2) speakers of Spanish are sensitive to the selectional restrictions that the different types of subjects impose on the choice of the two copulas. Twenty-four native speakers of Spanish and two groups of L2 Spanish speakers (24 beginners and 18 advanced speakers) were recruited to investigate the processing of ‘object/event + estar/ser’ permutations. Participants provided grammaticality judgments on correct (object + estar; event + ser) and incorrect (object + ser; event + estar) sentences while their brain activity was recorded. In line with previous studies (Leone-Fernández, Molinaro, Carreiras, & Barber, 2012; Sera, Gathje, & Pintado, 1999), the results of the grammaticality judgment for the native speakers showed that participants correctly accepted object + estar and event + ser constructions. In addition, while ‘object + ser’ constructions were considered grossly ungrammatical, ‘event + estar’ combinations were perceived as unacceptable to a lesser degree. For these same participants, ERP recording time-locked to the onset of the critical word ‘en’ showed a larger P600 for the ser predicates when the subject was an object than when it was an event (*La silla es en la cocina vs. La fiesta es en la cocina). This P600 effect is consistent with syntactic repair of the defining predicate when it does not fit with the adequate semantic properties of the subject. For estar predicates (La silla está en la cocina vs. *La fiesta está en la cocina), the findings showed a central-frontal negativity between 500–700 ms. Grammaticality judgment data for the L2 speakers of Spanish showed that beginners were significantly less

  6. Leucipo, Demócrito e Kant: uma Reflexão sobre a Equivalência entre Ser e Não-Ser

    OpenAIRE

    Eberth Eleuterio dos Santos

    2015-01-01

    De início, apresentaremos a tese de Demócrito e Leucipo, segundo a qual o ser não é mais que o não-ser, tendo como contraponto o pensamento eleata acerca da inexistência necessária do não-ser. Esta discussão nos remete à oposição entre o pleno (cheio) e o vazio que será posteriormente traduzida na oposição entre o ser e o nada (ou o não-ser). Desse modo, a oposição entre o pleno e o vazio é uma oposição que se desloca para o ser e o não-ser. Em seguida, faremos a apreciação do escrito pré-crí...

  7. Franz Brentano: equivocidad del ser y objeto intencional

    Directory of Open Access Journals (Sweden)

    Mario Ariel González Porta

    2002-06-01

    Full Text Available Este trabajo se propone probar que el concepto brentaniano de intencionalidad, más propiamente, su teoría de la inmanencia del objeto intencional y el posterior abandono de la misma, no pueden ser comprendidos de modo adecuado sino en el marco de las preocupaciones ontológicas del autor y, en particular, de su defensa inicial y subsiguiente rechazo de la tesis de la equivocidad del ser.This work aims to prove that the brentanian notion of intentionality, and particularly his conceptions of intentional object and immanence, cannot be properly understood but in the boundaries of the author' s ontological concerns, particularly his former defense and later denial of the equivocity of being.

  8. Synthesis, characterization and SERS activity of biosynthesized silver nanoparticles

    Science.gov (United States)

    Bindhu, M. R.; Sathe, V.; Umadevi, M.

    2013-11-01

    Silver nanoparticles were rapidly synthesized using Moringa oleifera flower extract as the reducing agent shows surface plasmon resonance peak at 439 nm. The size and shape of the nanoparticles controlled by varying the concentration of M. oleifera flower extract in the reaction medium. The synthesized silver nanoparticles were well-dispersed spherical nanoparticles with the average size of 14 nm. The retinoic acid present in M. oleifera flower extract used as reducing agent and proteins was responsible for capping of the bioreduced silver nanoparticles. The obtained nanoparticle shows size-dependent SERS activity. The SERS spectrum indicates that the pyridine adsorbed on the silver surface in a stand-on orientation via its nitrogen lone pair electrons.

  9. Highly reproducible SERS arrays directly written by inkjet printing

    Science.gov (United States)

    Yang, Qiang; Deng, Mengmeng; Li, Huizeng; Li, Mingzhu; Zhang, Cong; Shen, Weizhi; Li, Yanan; Guo, Dan; Song, Yanlin

    2014-12-01

    SERS arrays with uniform gold nanoparticle distribution were fabricated by direct-writing with an inkjet printing method. Quantitative analysis based on Raman detection was achieved with a small standard statistical deviation of less than 4% for the reproducibility and less than 5% for the long-term stability for 12 weeks.SERS arrays with uniform gold nanoparticle distribution were fabricated by direct-writing with an inkjet printing method. Quantitative analysis based on Raman detection was achieved with a small standard statistical deviation of less than 4% for the reproducibility and less than 5% for the long-term stability for 12 weeks. Electronic supplementary information (ESI) available: Additional information on the experimental details, gold nanoparticle characterization, and theoretical calculation for the diameters of contact area of droplets on substrates with different contact angles. See DOI: 10.1039/c4nr04656k

  10. Patchy silica-coated silver nanowires as SERS substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hunyadi Murph, Simona E.; Murphy, Catherine J.

    2013-05-08

    We report a class of core-shell nanomaterials that can be used as efficient surface-enhancement Raman scattering (SERS) substrates. The core consists of silver nanowires, prepared through a chemical reduction process, that are used to capture 4- mercaptobenzoic acid (4-MBA), a model analyte. The shell was prepared through a modified Stöber method and consists of patchy or full silica coats. The formation of silica coats was monitored via transmission electron microscopy, UV-visible spectroscopy and phase-analysis light scattering for measuring effective surface charge. Surprisingly, the patchy silica coated silver nanowires are better SERS substrate than silver nanowires; nanomolar concentration of 4-MBA can be detected. In addition, “nano-matryoshka” configurations were used to quantitate/explore the effect of the electromagnetic field at the tips of the nanowire (“hot spots”) in the Raman scattering experiment.

  11. Simultaneous SERS detection of copper and cobalt at ultratrace levels.

    Science.gov (United States)

    Tsoutsi, Dionysia; Guerrini, Luca; Hermida-Ramon, Jose Manuel; Giannini, Vincenzo; Liz-Marzán, Luis M; Wei, Alexander; Alvarez-Puebla, Ramon A

    2013-07-07

    We report a SERS-based method for the simultaneous and independent determination of two environmental metallic pollutants, Cu(ii) and Co(ii). This was achieved by exploiting the coordination-sensitive Raman bands of a terpyridine (TPY) derivative for detecting transition metal ions. Changes in the vibrational SERS spectra of dithiocarbamate anchored terpyridine (TPY-DTC) were correlated as a function of each metal ion concentration, with limits of detection comparable to those of several conventional analytical methods. Simultaneous detection of ultratrace levels of Co(ii) in the presence of high Cu(ii) concentration was also demonstrated, supporting the potential of this sensing strategy for monitoring potable water supplies.

  12. Hierarchical Ag mesostructures for single particle SERS substrate

    Science.gov (United States)

    Xu, Minwei; Zhang, Yin

    2017-01-01

    Hierarchical Ag mesostructures with highly rough surface morphology have been synthesized at room temperature through a simple seed-mediated approach. Electron microscopy characterizations indicate that the obtained Ag mesostructures exhibit a textured surface morphology with the flower-like architecture. Moreover, the particle size can be tailored easily in the range of 250-500 nm. For the growth process of the hierarchical Ag mesostructures, it is believed that the self-assembly mechanism is more reasonable rather than the epitaxial overgrowth of Ag seed. The oriented attachment of nanoparticles is revealed during the formation of Ag mesostructures. Single particle surface enhanced Raman spectra (sp-SERS) of crystal violet adsorbed on the hierarchical Ag mesostructures were measured. Results reveal that the hierarchical Ag mesostructures can be highly sensitive sp-SERS substrates with good reproducibility. The average enhancement factors for individual Ag mesostructures are estimated to be about 106.

  13. Aplicaciones del láser en odontologia

    OpenAIRE

    España Tost, A. J. (Antonio Jesús); Arnabat Domínguez, Josep; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2004-01-01

    Existen diferentes tipos de láseres que pueden tener aplicación en Odontología, y éstos pueden ser utilizados con diferentes fines. El propósito de este artículo es comentar, de forma genérica, el empleo de diferentes tipos de láseres en diversos tipos de tratamientos habituales en la práctica odontológica. No todos los láseres producen los mismos efectos; tampoco un mismo láser produce el mismo efecto sobre diferentes tejidos, y, según sean los parámetros de emisión utilizados, incluso el mi...

  14. A Novel Uncoded SER/BER Estimation Method

    Directory of Open Access Journals (Sweden)

    Mahesh Patel

    2015-06-01

    Full Text Available Due to the rapidly increasing data speed requirement, it has become essential to smartly utilize the available frequency spectrum. In wireless communications systems, channel quality parameters are often used to enable resource allocation techniques that improve system capacity and user quality. The uncoded bit or symbol error rate (SER is specified as an important parameter in the second and third generation partnership project (3GPP. Nonetheless, techniques to estimate the uncoded SER are usually not much published. This paper introduces a novel uncoded bit error rate (BER estimation method using the accurate-bits sequence of the new channel codes over the AWGN channel. Here, we have used the new channel codes as a forward error correction coding scheme for our communication system. This paper also presents the simulation results to demonstrate and compare the estimation accuracy of the proposed method over the AWGN channel.

  15. Shape-controllable gold nanostructures and their SERS enhancement

    Science.gov (United States)

    Ma, Ying; Promthaveepong, Kittithat; Li, Nan

    2016-10-01

    We report a new growth mechanism for the formation of gold (Au) nanoflowers (NFs) or Au nanoplates by simply tuning the solvent compositions. An aniline derivative N-(3-amidino)-aniline (NAAN) can reduce HAuCl4 to form AuNFs in water, while individual Au microplates were prepared in N-methyl-pyrrolidone (NMP)/water mixed solvents. Growth mechanism showed that incomplete coverage of Au (111) facets by oxidized product poly (N-(3-amidino)-aniline) (PNAAN) resulted in AuNFs, and improved coverage on Au (111) facet by NMP was favorable for individual Au microplate formation. The layered AuNFs showed 11 times SERS enhancement compared with randomly packed Au microplate film. As low as 10‑12 M 4-mercaptobenzoic acid (4-MBA) can be detected using AuNF as a SERS substrate.

  16. Reproducible Ultrahigh Electromagnetic SERS Enhancement in Nanosphere-Plane Junctions

    CERN Document Server

    Long, Jing; Li, Hongquan; Yang, Tian

    2015-01-01

    Surface enhanced Raman scattering (SERS) in nanoscale hotspots has been placed great hopes upon for identification of minimum chemical traces and in-situ investigation of single molecule structures and dynamics. However, previous work consists of either irreproducible enhancement factors (EF) from random aggregates, or moderate EFs despite better reproducibility. Consequently, systematic study of SERS at the single and few molecules level is still very limited, and the promised applications are far from being realized. Here we report EFs as high as the most intense hotspots in previous work yet achieved in a reproducible and well controlled manner, that is, electromagnetic EFs (EMEF) of 10^9~10 with an error down to 10^+/-0.08 from gold nanospheres on atomically flat gold planes under radially polarized (RP) laser excitation. In addition, our experiment reveals the EF's unexpected nonlinearity under as low as hundreds of nanowatts of laser power.

  17. Ser649 and Ser650 are the major determinants of protein kinase A-mediated activation of human hormone-sensitive lipase against lipid substrates

    DEFF Research Database (Denmark)

    Krintel, Christian; Osmark, Peter; Larsen, Martin Rask;

    2008-01-01

    Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from stored triacylglycerols. Its activity is regulated by reversible protein phosphorylation. In rat HSL Ser563, Ser659 and Ser660 have been shown to be phosphorylated by protein kinase A (PKA) in vitro as well...

  18. Donació de llibre "El arte de ser totonaca"

    OpenAIRE

    Solanilla Demestre, Victòria

    2009-01-01

    El 5 de febrer de 2009 a la Biblioteca d'Humanitats, en un acte senzill i alhora carregat de significació, una representació de l'Estat de Veracruz va fer una donació del llibre "El arte de ser totonoca" al Grup d'Estudis Precolombins de la UAB, que al seu torn en va fer donació a la Biblioteca d'Humanitats

  19. Sobre mi traducción de "Ser y Tiempo"

    OpenAIRE

    2005-01-01

    Este escrito pretende dos cosas: primero, desarrollar brevemente mi propia idea de lo que es traducir, y, segundo, explicar la solución que di a ciertos problemas que surgieron en mi traducción de la obra "Ser y Tiempo" de Heidegger. (In this article the author develops his own idea of a translation and explains the solutions given to problems arisen in the translation of Heidegger’s Being and Time.)

  20. Sobre mi traducción de "Ser y Tiempo"

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Rivera

    2005-12-01

    Full Text Available Este escrito pretende dos cosas: primero, desarrollar brevemente mi propia idea de lo que es traducir, y, segundo, explicar la solución que di a ciertos problemas que surgieron en mi traducción de la obra "Ser y Tiempo" de Heidegger. (In this article the author develops his own idea of a translation and explains the solutions given to problems arisen in the translation of Heidegger’s Being and Time.

  1. Plasmonic Paper as a Highly Efficient SERS Substrate

    Science.gov (United States)

    2012-09-01

    diagnostic devices by printing microfluidic patterns on paper, which create hydrophobic barriers that define channels and reaction zones to fabricate an...trace detection on real-world surfaces,” ACS Appl. Mater. Interfaces, 2(12), 3429-3435 (2010). [24] Yu, W. W. and White, I. M., “ Inkjet printed ...scaffolding format. We discuss the fabrication , physical characterization and SERS activity of our novel substrates using non-resonant analytes. 15

  2. Significado de ser docente para el adulto mayor sanfernandino

    OpenAIRE

    Martina, Martha; Facultad de Medicina, UNMSM; Santos, Gladys; Facultad de Medicina, UNMSM; Lema, Julia; Facultad de Medicina, UNMSM

    2013-01-01

    Objetivos: Comprender el significado de ser docente para el adulto mayor de la Facultad de Medicina de San Marcos y describir las motivaciones que determinan, de alguna forma, su decisión de postergar su retiro, no obstante haber cumplido con los requisitos legales para la jubilación. Diseño: Estudio de caso cualitativo. Institución: Facultad de Medicina, UNMSM. Participantes: Docentes adulto mayores de la Facultad de Medicina. Intervenciones: Entrevista a profundidad. Principales medidas de ...

  3. Long-term photopolarimetric variability of DD Ser

    Science.gov (United States)

    Belan, S. P.; Shakhovskoy, D. N.

    2013-12-01

    We present some results of UBVRI-photopolarimetric observations of DD Ser, a poorly studied and understood Ae-star. The long-term component of light variation is detected, with the period of about fifteen years. Variability of the degree and positional angle of linear polarization is observed as well. Analysis of correlation between photometric and polarimetric data shows that observed light minima are likely caused by variability of circumstellar extinction produced by dust.

  4. GEOGRAFIA E ONTOLOGIA: O FUNDAMENTO GEOGRÁFICO DO SER

    Directory of Open Access Journals (Sweden)

    Elvio Rodrigues Martins

    2007-08-01

    Full Text Available Este trabalho busca a definição do fundamento geográfico como uma das determinações constituintes do ser do homem e da sociedade. Para tanto, retoma alguns dos fundamentos epistemológicos da ciência geográfica, no sentido de redefini-los, e com isso estabelecer novas bases para a relação entre ontologia e Geografia.

  5. Laser in medicine Láser en medicina

    Directory of Open Access Journals (Sweden)

    Juan C. Cárdenas

    1993-03-01

    Full Text Available The fundamentals of laser functioning and a brief historic description on the subject are presented; laser Is classified according to emission potency, materials with which it is built and pulsation. Different mechanisms of action of laser as well as Its indications and contraindications are discussed. Emphasis is given to low-power laser. Local and foreign experiences with Its medlcal use are briefly described

    Se revisan los principios fundamentales del funcionamiento del láser, se hace una breve revisión histórica del mismo y se lo clasifica de acuerdo con la potencia de emisión, los materiales de fabricación y la pulsación. Se enumeran los diferentes mecanismos de acción del láser y sus indicaciones y contraindicaciones haciendo énfasis en lo concerniente al láser de baja potencia, tanto pulsado como no pulsado; se alude a las experiencias nacionales y de otros países.

  6. A possible giant planet orbiting the cataclysmic variable LX Ser

    CERN Document Server

    Li, K; Zhou, J -L; Wu, D -H; Guo, D -F; Jiang, Y -G; Gao, D -Y; Chen, X; Wang, X -Y

    2016-01-01

    LX Ser is a deeply eclipsing cataclysmic variable with an orbital period of $0.^d 1584325$. Sixty two new eclipse times were determined by our observations and the AAVSO International Data base. Combining all available eclipse times, we analyzed the O-C behavior of LX Ser. We found that the O-C diagram of LX Ser shows a sinusoidal oscillation with a period of 22.8 yr and an amplitude of 0.00035 days. Two mechanisms (i.e., the Applegate mechanism and the light travel time effect) are applied to explain the cyclic modulation. We found that the Applegate mechanism is difficult to explain the cyclic oscillation in the orbital period. Therefore, the cyclic period change is most likely to be caused by the light travel time effect due to the presence of a third body. The mass of the tertiary component was determined to be $M_3\\sim7.5 M_{Jup}$. We supposed that the tertiary companion is plausible a giant planet. The stability of the giant planet was checked, and we found that the multiple system is stable.

  7. A possible giant planet orbiting the cataclysmic variable LX Ser

    Science.gov (United States)

    Li, Kai; Hu, Shaoming; Zhou, Jilin; Wu, Donghong; Guo, Difu; Jiang, Yunguo; Gao, Dongyang; Chen, Xu; Wang, Xianyu

    2017-02-01

    LX Ser is a deeply eclipsing cataclysmic variable with an orbital period of 0.1584325 d. 62 new eclipse times were determined by our observations and the AAVSO International Data base. Combining all available eclipse times, we analyzed the O - C behavior of LX Ser. We found that the O - C diagram of LX Ser shows a sinusoidal oscillation with a period of 22.8 yr and an amplitude of 0.00035 d. Two mechanisms (i.e., the Applegate mechanism and the light-travel time effect) are applied to explain the cyclic modulation. We found that it is difficult to apply the Applegate mechanism to explain the cyclic oscillation in the orbital period. Therefore, the cyclic period change is most likely to be caused by the light-travel time effect due to the presence of a third body. The mass of the tertiary component was determined to be M3 ∼ 7.5 MJup. We supposed that the tertiary companion is plausibly a giant planet. The stability of the giant planet was checked, and we found that the multiple system is stable.

  8. Facile Nanostructured Substrate Preparation Using Gold Nanocuboids for SERS

    Directory of Open Access Journals (Sweden)

    Pablo Genaro Martínez-Torres

    2015-04-01

    Full Text Available In the present work, we report a practical fabrication method of gold-aluminium substrates for surface en‐ hanced Raman spectroscopy. A commercial aluminium- foil was used to fabricate SERS substrates by depositing gold nanocuboids and faceted particles onto their surfaces using the drop-drying method. The gold nanoparticles were characterized by ultraviolet-visible spectroscopy, while the size and morphology were determined by field emission scanning electron microscopy. The perform‐ ance of the substrates was investigated using Rhoda‐ mine 6G in a water solution where a volume of 3 μl was placed on the surfaces of the SERS substrates, and the Raman spectra were immediately acquired using diode laser excitation at 785 nm. The estimated analytical enhancement factor of the gold-aluminium substrates was 1.8 x 106, using a solution of Rhodamine 6G with a concentration of 1 x 109 (0.4796 ppb. We show that our SERS substrates can be easily fabricated, and that they are reproducible and have suitable surface uniformity, thus allowing one to analyse Rhodamine 6G not only as a dry sample, but also in a solution.

  9. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    Science.gov (United States)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  10. SERS study of the complexes of thiamine derivatives with pyruvate

    Science.gov (United States)

    Strekal, N. D.; Gachko, G. A.; Kivach, L. N.; Maskevich, S. A.

    1992-03-01

    The SER spectra of thiamine (T) 4'-hydroxythiamine (HOT), thiamine disphoshate (TDP) on silver electrode at acidic and neutral solution have been investigated. The influence of pyruvate (Pyr) on SER spectra at various applied voltages 0 - -0, 65 V has been studied. In the acidic solution T and TDP interact with the surface by means of the heteroatom of N of the pyrimidine and heteroatoms of N and S of thiazolium ring. The characteristic bands at 665, 755, 1210 and 1640 cm -1 are observed in SERS spectra. It is not detected the interaction of N atom of thiazolium ring of HOT with the silver surface. The Cl - ions play an important role in adsorption of these molecules. In the acidic solution Pyr enhances the interaction of thiazolium moiety of TDP with surface and decrease that of HOT. In the neutral solution and applied voltages more positive than> -0,5 V molecules of T derivatives desorptes and Pyr promotes that. The possible mechanisms of the influence of Pyr on adsorption of the T derivatives are discussed.

  11. Label-free monitoring of individual DNA hybridization using SERS

    Science.gov (United States)

    Qi, Ji; Zeng, Jianbo; Zhao, Fusheng; Santos, Greggy M.; Lin, Steven Hsesheng; Raja, Balakrishnan; Strych, Ulrich; Willson, Richard C.; Shih, Wei-Chuan

    2015-03-01

    Sequence-specific detection of DNA hybridization at the single-molecule level has been instrumental and gradually become a ubiquitous tool in a wide variety of biological and biomedical applications such as clinical diagnostics, biosensors, and drug development. Label-free and amplification-free schemes are of particular interest because they could potentially provide in situ monitoring of individual hybridization events, which may lead to techniques for discriminating subtle variations due to single-base modification without stringency control or repetitive thermal cycling. Surface-enhanced Raman spectroscopy (SERS) has been widely used for molecular detection and identification by exploiting the localized surface plasmon resonance effect when the target molecules are near gold or silver nanostructures. However, effective and robust SERS assays have yet become a reality for trace detection. Recently, we have developed a SERS substrate by shaping nanoporous gold thin films into monolithic submicron disks, called nanoporous gold disks (NPGD). Here we demonstrate in situ monitoring of the same immobilized ssDNA molecules and their individual hybridization events.

  12. Ser649 and Ser650 are the major determinants of protein kinase A-mediated activation of human hormone-sensitive lipase against lipid substrates.

    Directory of Open Access Journals (Sweden)

    Christian Krintel

    Full Text Available BACKGROUND: Hormone-sensitive lipase (HSL is a key enzyme in the mobilization of fatty acids from stored triacylglycerols. Its activity is regulated by reversible protein phosphorylation. In rat HSL Ser563, Ser659 and Ser660 have been shown to be phosphorylated by protein kinase A (PKA in vitro as well as in vivo. METHODOLOGY/PRINCIPAL FINDINGS: In this study we employed site-directed mutagenesis, in vitro phosphorylation and mass spectrometry to show that in vitro phosphorylation of human HSL by PKA occurs primarily on Ser649 and Ser650 (Ser659 and Ser660 in rat HSL. The wild type enzyme and four mutants were expressed in C-terminally His-tagged form in Sf9 insect cells and purified to homogeneity. HSL variants in which Ser552 and/or Ser554 were mutated to Ala or Glu retained both lipolytic and non-lipolytic activity and were phosphorylated by PKA and activated to a similar extent as the wild type enzyme. (32P-labeling studies revealed that the bulk of the phosphorylation was on the Ser649/Ser650 site, with only a minor phosphorylation of Ser552 and Ser554. MS/MS analysis demonstrated that the peptide containing Ser649 and Ser650 was primarily phosphorylated on Ser650. The mutant lacking all four serines had severely reduced lipolytic activity, but a lesser reduction in non-lipolytic activity, had S(0.5 values for p-nitrophenol butyrate and triolein comparable to those of wild type HSL and was not phosphorylated by PKA. PKA phosphorylation of the wild type enzyme resulted in an increase in both the maximum turnover and S(0,5 using the TO substrate. CONCLUSIONS: Our results demonstrate that PKA activates human HSL against lipid substrates in vitro primarily through phosphorylation of Ser649 and Ser650. In addition the results suggest that Ser649 and Ser650 are located in the vicinity of a lipid binding region and that PKA phosphorylation controls the accessibility of this region.

  13. The Theory of SERS on Dielectrics and Semiconductors

    CERN Document Server

    Polubotko, V P Chelibanov A M

    2016-01-01

    It is demonstrated that the reason of SERS on dielectric and semiconductor substrates is the enhancement of the electric field in the regions of the tops of the surface roughness with very small radius, or a very large curvature. The enhancement depends on the dielectric constant of the substrate and is stronger for a larger dielectric constant. It is indicated that the enhancement on dielectrics and semiconductors is stronger than on metals with the same modulus of the dielectric constant. The result obtained is confirmed by experimental data on the enhancement coefficients obtained for various semiconductor and dielectric substrates.

  14. Fabricación aditiva con láser

    OpenAIRE

    Juan José de Damborenea González

    2015-01-01

    En menos de 30 años, la fabricación aditiva (en la literatura AM, Additive Manufacturing) la irrumpido con fuerza en el campo del procesamiento de materiales, especialmente desde 2007. De los diferentes métodos existentes para la fabricación de piezas por AM, el empleo de haces de alta densidad energética como el haz de electrones o el láser, se han mostrado particularmente valiosos por su capacidad para fabricar prototipos con diferentes composiciones y formas. La fabricación aditiva con lás...

  15. SERS-active nanoparticle aggregate technology for tags and seals

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Leif O [Los Alamos National Laboratory; Montoya, Velma M [Los Alamos National Laboratory; Havrilla, George J [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory

    2010-06-03

    In this paper, we describe our efforts to create a modern tagging and sealing technology for international safeguards application. Our passive tagging methods are based on SANAs (SERS-Active Nanoparticle Aggregates; SERS: Surface Enhanced Raman Scattering). These SANAs offer robust spectral barcoding capability in an inexpensive tag/seal, with the possibility of rapid in-field verification that requires no human input. At INMM 2009, we introduced SANAs, and showed approaches to integrating our technology with tags under development at Sandia National Laboratories (SNL). Here, we will focus on recent LANL development work, as well as adding additional dimensionality to the barcoding technique. The field of international safeguards employs a broad array of tags, seals, and tamper-indicating devices to assist with identification, tracking, and verification of components and materials. These devices each have unique strengths suited to specific applications, and span a range of technologies from passive metal cup seals and adhesive seals to active, remotely monitored fiber optic seals. Regardless of the technology employed, essential characteristics center around security, environmental and temporal stability, ease of use, and the ability to provide confidence to all parties. Here, we present a new inexpensive tagging technology that will deliver these attributes, while forming the basis of either a new seal, or as a secure layer added to many existing devices. Our approach uses the Surface Enhanced Raman Scattering (SERS) response from SANAs (SERS-Active Nanoparticle Aggregates, Figure 1) to provide a unique identifier or signature for tagging applications. SANAs are formed from gold or silver nanoparticles in the 40-80 nm size range. A chemical dye is installed on the nanoparticle surface, and the nanoparticles are then aggregated into ensembles of {approx}100 to 500 nm diameter, prior to being coated with silica. The silica shell protects the finished SANA from

  16. Los abusos sexuales: el riesgo de ser mujer

    OpenAIRE

    López Sánchez, Félix

    2005-01-01

    El objetivo de este artículo es revisar los estudios sobre abusos sexuales realizados nacional e internacionalmente, teniendo en cuenta la perspectiva de género. Todos los estudios analizados muestran de manera contundente que las niñas tienen el doble de posibilidades de ser víctimas que los niños, si bien ellos también lo son con frecuencia. Desde el punto de vista de los abusadores y agresores sexuales las diferencias de sexo son espectaculares: los abusadores y agresores...

  17. ¿Qué quiero ser de mayor?

    OpenAIRE

    Polo González, María Eugenia

    2011-01-01

    El escenario sociodemográfico actual hace que se dibuje un panorama novedoso en torno a la vejez que dista del de hace décadas. El hecho de que la jubilación no sea el final del camino, sino una etapa más de la vida induce, llegado el momento, a que el plantearse qué queremos ser de mayores cobre sentido. Algunos optan por el aprendizaje a lo largo de toda la vida, asistiendo, entre otras cosas, a la universidad. En el caso que nos ocupa, a esta circunstancia se añade la convivencia entre gen...

  18. Silver coated aluminium microrods as highly colloidal stable SERS platforms.

    Science.gov (United States)

    Pazos-Perez, Nicolas; Borke, Tina; Andreeva, Daria V; Alvarez-Puebla, Ramon A

    2011-08-01

    We report on the fabrication of a novel material with the ability to remain in solution even under the very demanding conditions required for structural and dynamic characterization of biomacromolecule assays. This stability is provided by the increase in surface area of a low density material (aluminium) natively coated with a very hydrophilic surface composed of aluminium oxide (Al(2)O(3)) and metallic silver nanoparticles. Additionally, due to the dense collection of active hot spots on their surface, this material offers higher levels of SERS intensity as compared with the same free and aggregated silver nanoparticles.

  19. EL PROCESO DE SER HISTERECTOMIZADA: ASPECTOS EDUCATIVOS A CONSIDERAR

    OpenAIRE

    Araya G,Alejandra; Urrutia S.,María Teresa

    2008-01-01

    Antecedentes: La histerectomía es una de las cirugías más frecuente en el mundo entero. La principal patología causante es la miomatosis uterina. A pesar de lo común de la cirugía, existe déficit en torno a la educación otorgada a este grupo de mujeres. Objetivo: El objetivo de la presente revisión bibliográfica es describir los aspectos que deben ser considerados al momento de educar a la mujer histerectomizada, específicamente las características que debiera tener el profesional, los conten...

  20. Radial system of dark globules in Ser OB2

    Science.gov (United States)

    Gyulbudaghian, A. L.

    2012-09-01

    A radial system illuminated by bright, central OB stars is discussed. 12CO(1-0) observations are made of three globules from this system. Three molecular clouds are detected which are dark globules of a radial system in Ser OB2. A group of IR stars near the boundary of a globule with a rim is studied. One of the IR stars with bright filaments is a YSO (young stellar object). The radial system contains two bright, Mshaped fronts located at the tip of a jet, which may have emerged from the Wolf-Rayet star WR113. Similar M-shaped fronts are also located near the object SNO 85.

  1. RECURSOS NO CONVENCIONALES SUSCEPTIBLES DE SER EXPLOTADOS MEDIANTE FRACKING

    OpenAIRE

    Jódar Abellán, Antonio

    2014-01-01

    En el presente trabajo se analizan en detalle los recursos de origen no convencional existentes en el contexto internacional, europeo, nacional y regional, que pueden ser explotados mediante fracking. Así mismo, se mencionará someramente la legislación aplicable a la fracturación hidráulica y los impactos, tanto beneficiosos como perjudiciales, que ésta puede acarrear. El estudio finaliza con una propuesta de posibles lugares en la Península Ibérica donde dicha técnica reporte mayores benefic...

  2. Aspectos sociales del documental “Ser y Tener”

    OpenAIRE

    Marín Gutiérrez, Isidro

    2010-01-01

    Después de haber expuesto a la clase los temas 5 (Sociedad, cultura y educación), el tema 6 (el proceso de socialización), tema 7 (estratificación, movilidad social y educación) y tema 8 (educación y control social) de sociología de la educación. Se pondrá el documental “Ser y Tener”. Posteriormente habrá un debate sobre el documental y sobre los conceptos sociológicos que en ella salgan.

  3. Development and precise characterization of phospho-site-specific antibody of Ser(357) of IRS-1: elimination of cross reactivity with adjacent Ser(358).

    Science.gov (United States)

    Waraich, Rizwana Sanaullah; Zaidi, Nousheen; Moeschel, Klaus; Beck, Alexander; Weigert, Cora; Voelter, Wolfgang; Kalbacher, Hubert; Lehmann, Rainer

    2008-11-07

    Antibodies that recognize specifically phosphorylated sites on proteins are widely utilized for studying the regulation and biological function of phosphoproteins. The proposed strategy is a powerful, analytical tool allowing the generation of phospho-site specific antibodies albeit adjacent phosphorylation sites are present. Here, we demonstrate the assessment and elimination of cross reactivity of phospho-site-specific-Ser(357) IRS-1 antibody. While determining the specificity of p-Ser(357) antiserum we came across the cross reactivity of the antiserum with adjacent Ser(358) which was successfully abolished by an improved immuno-purification method. The specificity of the purified antiserum was then verified by indirect ELISA, results of ELISA were also mirrored in the experiments carried out in BHK-IR cells using different mutants of IRS-1 carrying mutations at either Ser(357)/Ser(358)/Ser(357/358). Immuno-purified-p-Ser(357) did not react with IRS-1 Ala(357) and IRS-1 Ala(357/358). In conclusion, the present study describes generation and characterization of p-Ser(357) IRS-1 antibody, which reacts with IRS-1 in site specific and phosphorylation state-dependent manner without showing cross reactivity to adjacent Ser(358). This antibody can be effectively used to further clarify the inhibitory role of Ser(357) in insulin signal transduction.

  4. LAS CONSECUENCIAS JURÍDICAS DE NO SER UNA PROVINCIA*

    Directory of Open Access Journals (Sweden)

    Leonardo Hugo Limanski

    2015-09-01

    Full Text Available En el presente trabajo se analiza, en forma profunda, la autonomía de la Ciudad Autónoma de Buenos Aires, en comparación con las 23 provincias argentinas. A su vez, se intentará demostrar que la Ciudad de Buenos Aires debe ser tratada en forma equivalente a una provincia, desarrollando los problemas que la interpretación actual de la Constitución Nacional por parte de la Corte Suprema acarrea. A los efectos de lograr una cabal comprensión del tema se realizará una breve reseña histórica partiendo desde la federalización en el año 1880, y se hará hincapié en aquellos temas que, creo, violan la igualdad. Es así que se pondrán de manifiesto cuales son las consecuencias jurídicas de no ser considerada una provincia y, por último, se realizará una aproximación al vínculo existente entre las comunas y los municipios, a efectos de dejar planteado un problema

  5. Development of an optofluidic SERS-based biomedical sensor

    Science.gov (United States)

    Walton, Brian; Huang, Po-Jung; Kameoka, Jun; Deutz, Nicolaas; Coté, Gerard L.

    2016-03-01

    Rapid assessment of radiation exposure to sensitive organs like the gut is extremely important for large populations exposed to ionized radiation, for instance during warfare. Recent results have shown that plasma citrulline levels appear to track gut function after irradiation levels in mice and humans. The current ways to monitor blood citrulline levels are bulky, laborious, time-consuming and expensive methods. Therefore, an optofludic point-of-care (POC) system using surface enhanced Raman spectroscopy to measure plasma citrulline as a marker for radiation exposure that overcomes the above issues is being developed. As a first step toward development of this system four colloidal nanoparticles, spherical gold, silver cubes, silica-gold nanoshells, and silver-gold nanocages have been analyzed for use in the POC system. Transmission electron microscopy (TEM) images have been taken of each nanoparticle to visualize the morphology of the nanoparticles, which is vital for SERS. Ultraviolet-visible (UV/Vis) spectroscopy was also collected to verify the extinction spectra for each nanoparticle was in resonance with the excitation wavelength. The nanoparticles were functionalized with mercaptobenzoic acid (MBA), a Raman reporter molecule, and SERS spectra were collected to determine which has better utility in a novel micro-to-nanochannel. The data showed that the silver nanocubes have a larger enhancement factor than the gold nanospheres, nanoshells, or nanocages. Currently, these nanocubes are being functionalized with the citulline for assessing the concentration sensitivity and dynamic range for ultimate use as a marker for radiation.

  6. Based on time and spatial-resolved SERS mapping strategies for detection of pesticides.

    Science.gov (United States)

    Ma, Bingbing; Li, Pan; Yang, Liangbao; Liu, Jinhuai

    2015-08-15

    For the sensitive and convenient detection of pesticides, several sensing methods and materials have been widely explored. However, it is still a challenge to obtain sensitive, simple detection techniques for pesticides. Here, the simple and sensitive Time-resolved SERS mapping (T-SERS) and Spatial-resolved SERS mapping (S-SERS) are presented for detection of pesticides by using Au@Ag NPs as SERS substrate. The Time-resolved SERS mapping (T-SERS) is based on state translation nanoparticles from the wet state to the dry state to realize SERS measurements. During the SERS measurement, adhesive force drives the particles closer together and then average interparticle gap becomes smaller. Following, air then begins to intersperse into the liquid network and the particles are held together by adhesive forces at the solid-liquid-air interface. In the late stage of water evaporation, all particles are uniformly distributed. Thus, so called hotspots matrix that can hold hotspots between every two adjacent particles in efficient space with minimal polydispersity of particle size are achieved, accompanying the red-shift of surface plasmon peak and appearance of an optimal SPR resonated sharply with excitation wavelength. Here, we found that the T-SERS method exhibits the detection limits of 1-2 orders of magnitude higher than that of S-SERS. On the other hand, the T-SERS is very simple method with high detection sensitivity, better reproducibility (RSD=10.8%) and is beneficial to construction of a calibration curve in comparison with that of Spatial-resolved SERS mapping (S-SERS). Most importantly, as a result of its remarkable sensitivity, T-SERS mapping strategies have been applied to detection of several pesticides and the detect limit can down to 1nM for paraoxon, 0.5nM for sumithion. In short, T-SERS mapping measurement promises to open a market for SERS practical detection with prominent advantages.

  7. P21 Ser31Arg polymorphism and cervical cancer risk: a meta-analysis.

    Science.gov (United States)

    Li, Ya; Liu, Fei; Tan, Shiqiao; Li, Shangwei

    2011-04-01

    Studies investigating the association between p21 genetic polymorphism Ser31Arg and cervical cancer (CC) risk report conflicting results. The aim of this study was to quantitatively summarize the evidence for p21 polymorphism and CC risk. Two investigators independently searched the MEDLINE, Embase, CNKI, and Chinese Biomedicine databases. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for p21 polymorphism and CC were calculated in a fixed effects model (the Mantel-Haenszel method) and a random effects model (the DerSimonian and Laird method) when appropriate. The pooled ORs were performed for codominant model (Arg/Arg vs Ser/Ser and Arg/Ser vs Ser/Ser), dominant model (Arg/Arg + Arg/Ser vs Ser/Ser), and recessive model (Arg/Arg vs Arg/Ser + Ser/Ser). Subgroup analyses were performed by country, matched controls, and Hardy-Weinberg equilibrium in the controls and study sample size. This meta-analysis included 10 case-control studies from an Asian population, which included 1415 CC cases and 1947 controls. Overall, the variant genotypes (Arg/Arg and Arg/Ser) of Ser31Arg were not associated with CC risk, when compared with the wild-type homozygote Ser/Ser (Arg/Arg vs Ser/Ser: OR, 1.30; 95% CI, 0.81-2.08; Arg/Ser vs Ser/Ser: OR, 1.06; 95% CI, 0.72-1.55). Similarly, no associations were found in the dominant and recessive models (dominant model: OR, 1.05; 95% CI, 0.73-1.51; recessive model: OR, 1.28; 95% CI, 0.86-1.90). Stratified analyses also detected no significant association in any subgroup, except among those studies from "other" country and those studies with controls deviated from Hardy-Weinberg equilibrium. No association was found between the p21 polymorphism Arg31Ser and risk of CC among Asians. In the future, additional studies based on white and African American patients should be performed to re-evaluate the association.

  8. Parkin is activated by PINK1-dependent phosphorylation of ubiquitin at Ser65

    Science.gov (United States)

    Kazlauskaite, Agne; Kondapalli, Chandana; Gourlay, Robert; Campbell, David G.; Ritorto, Maria Stella; Hofmann, Kay; Alessi, Dario R.; Knebel, Axel; Trost, Matthias; Muqit, Miratul M. K.

    2014-01-01

    We have previously reported that the Parkinson's disease-associated kinase PINK1 (PTEN-induced putative kinase 1) is activated by mitochondrial depolarization and stimulates the Parkin E3 ligase by phosphorylating Ser65 within its Ubl (ubiquitin-like) domain. Using phosphoproteomic analysis, we identified a novel ubiquitin phosphopeptide phosphorylated at Ser65 that was enriched 14-fold in HEK (human embryonic kidney)-293 cells overexpressing wild-type PINK1 stimulated with the mitochondrial uncoupling agent CCCP (carbonyl cyanide m-chlorophenylhydrazone), to activate PINK1, compared with cells expressing kinase-inactive PINK1. Ser65 in ubiquitin lies in a similar motif to Ser65 in the Ubl domain of Parkin. Remarkably, PINK1 directly phosphorylates Ser65 of ubiquitin in vitro. We undertook a series of experiments that provide striking evidence that Ser65-phosphorylated ubiquitin (ubiquitinPhospho−Ser65) functions as a critical activator of Parkin. First, we demonstrate that a fragment of Parkin lacking the Ubl domain encompassing Ser65 (ΔUbl-Parkin) is robustly activated by ubiquitinPhospho−Ser65, but not by non-phosphorylated ubiquitin. Secondly, we find that the isolated Parkin Ubl domain phosphorylated at Ser65 (UblPhospho−Ser65) can also activate ΔUbl-Parkin similarly to ubiquitinPhospho−Ser65. Thirdly, we establish that ubiquitinPhospho−Ser65, but not non-phosphorylated ubiquitin or UblPhospho−Ser65, activates full-length wild-type Parkin as well as the non-phosphorylatable S65A Parkin mutant. Fourthly, we provide evidence that optimal activation of full-length Parkin E3 ligase is dependent on PINK1-mediated phosphorylation of both Parkin at Ser65 and ubiquitin at Ser65, since only mutation of both proteins at Ser65 completely abolishes Parkin activation. In conclusion, the findings of the present study reveal that PINK1 controls Parkin E3 ligase activity not only by phosphorylating Parkin at Ser65, but also by phosphorylating ubiquitin at Ser65

  9. Sandwich-like layer-by-layer assembly of gold nanoparticles with tunable SERS properties

    Directory of Open Access Journals (Sweden)

    Zhicheng Liu

    2016-07-01

    Full Text Available Sandwich-like layer-by-layer thin films consisting of polyelectrolytes and gold nanoparticles were utilized to construct surface-enhanced Raman scattering (SERS substrates with tunable SERS properties. It is found that both the size of the nanoparticles in the layers and the interlayer distance significantly influence the SERS performance of the multilayered thin film. These simple, low-cost, easily processable and controllable SERS substrates have a promising future in the field of molecular sensing.

  10. Gold nanoparticle-coated biomaterial as SERS micro-probes

    Indian Academy of Sciences (India)

    G V Pavan Kumar

    2011-06-01

    We report for the first time, on the utility of plant-based biomaterial as enhanced-Raman scattering probes. The bio-substrate used in this study are commonly found in plant extracts, and are cost-effective, mechanically robust, flexible and easily transportable. The probe was fabricated by coating the plant extract with gold nanoparticles and characterized. By employing a ‘single-touch contact’ method, we reveal the ability of these probes to detect routinely used Raman markers such as 2-napthalenethiol and rhodamine B, at nano-molar concentrations, in dry and liquid forms, respectively. Reproducibility of the signals with variation <5%, and the ability to detect biomolecules are demonstrated herein. We envision these bio-probes as potential candidates for enhanced Raman sensing in chemical, environmental, and archaeological applications. By further engineering the shape, morphology, and surface chemistry of these micro-probes, we foresee their utility as miniaturized, natural SERS substrates.

  11. La razón de ser de los conglomerantes

    Directory of Open Access Journals (Sweden)

    Fernández Paris, J. M.

    1978-09-01

    Full Text Available La palabra cemento sirve para designar cualquier sustancia con capacidad adherente, mientras que el término conglomerante se aplica a la acción de aglutinar en un todo partículas que anteriormente estaban sueltas o independientes. Según su capacidad o no de endurecer bajo agua, los conglomerantes se clasifican en hidráulicos y no hidráulicos. Se denominan hidráulicos a aquéllos que tienen la citada facultad. Entre todos los conglomerantes hidráulicos, han adquirido en la construcción una carta de naturaleza inusitada durante los últimos tiempos los denominados cementos porland. Quiero hacer constar que trato de exponer simplemente aquellos conceptos químicos que, a mi modo de ver y de acuerdo con mi experiencia, constituyen la razón de ser que nos permita apreciar sus cualidades y propiedades.

  12. Au-Ag hollow nanostructures with tunable SERS properties

    Science.gov (United States)

    Jiji, S. G.; Gopchandran, K. G.

    2017-01-01

    Fabrication of hollow Au-Ag nanoparticles is done by the sequential action of galvanic replacement and Kirkendall effect. Polyol synthesized silver nanoparticles were used as templates and the size of cavities is controlled by the systematic addition of the HAuCl4. Au-Ag nanoparticles carved in different depths were tested for application as substrates for surface enhanced Raman scattering. Two medically important Raman active analytes-Nile blue chloride and Crystal violet were used in the surface enhanced Raman scattering (SERS) performance analysis. A systematic study has been made on the Raman enhancement of hollow nanoparticles fabricated with different cavity dimensions and compared with that of the silver templates used. The enhancement observed for these hollow substrates with cavities is of interest since Au protected hollow nanostructures are vital and an active area of interest in drug delivery systems.

  13. Nanofabrication of SERS Substrates for Single/Few Molecules Detection

    KAUST Repository

    Melino, Gianluca

    2015-05-04

    Raman spectroscopy is among the most widely employed methods to investigate the properties of materials in several fields of study. Evolution in materials science allowed us to fabricate suitable substrates, at the nanoscale, capable to enhance the electromagnetic field of the signals coming from the samples which at this range turn out to be in most cases singles or a few molecules. This particular variation of the classical technique is called SERS (Surface Enanched Raman Spectroscopy). In this work, the enhancement of the electromagnetic field is obtained by manipulation of the optical properties of metals with respect to their size. By using electroless deposition (bottom up technique), gold and silver nanoparticles were deposited in nanostructured patterns obtained on silicon wafers by means of electron beam lithography (top down technique). Rhodamine 6G in aqueous solution at extremely low concentration (10-8 M) was absorbed on the resultant dimers and the collection of the Raman spectra demonstrated the high efficiency of the substrates.

  14. Ser excepción o del individualismo.

    Directory of Open Access Journals (Sweden)

    Juan Fernando Pérez.

    1998-06-01

    Full Text Available Lección inaugural de la Maestría en Ciencias Sociales: Psicoanálisis, Cultura y Vínculo social. A partir del texto de Freud Los seres excepcionales (también traducido Las excepciones el autor interroga una categoría no psicoanalítica como es la de individualismo, con el concepto de Freud allí expuesto. Propone que el concepto freudiano ser excepción, permite pensar al menos algunas dimensiones de la fenomenología descrita bajo la categoría de individualismo, hecho de interés particular para el examen de algunas modalidades del malestar contemporáneo y de la naturaleza del vínculo social que ese mundo propone. En este orden de ideas aparece cómo las dos figuras que Freud define al lado de “las excepciones”, es decir “los delincuentes por sentimientos de culpa” y “los que fracasan al triunfar”, tienden a desdibujarse en las sociedades de hoy, en favor de una mayor significación esta forma singular de individualismo como es la de “ser excepción”. El hecho revela en forma bien específica cómo el declinamiento de padre en la época de la ciencia implica el fortalecimiento de la tendencia particular del sujeto contemporáneo de definirse como excepción frente a la ley.

  15. Timing variations in the secondary eclipse of NN Ser

    Science.gov (United States)

    Parsons, S. G.; Marsh, T. R.; Bours, M. C. P.; Littlefair, S. P.; Copperwheat, C. M.; Dhillon, V. S.; Breedt, E.; Caceres, C.; Schreiber, M. R.

    2014-02-01

    The eclipsing white dwarf plus main-sequence binary NN Serpentis provides one of the most convincing cases for the existence of circumbinary planets around evolved binaries. The exquisite timing precision provided by the deep eclipse of the white dwarf has revealed complex variations in the eclipse arrival times over the last few decades. These variations have been interpreted as the influence of two planets in orbit around the binary. Recent studies have proved that such a system is dynamically stable over the current lifetime of the binary. However, the existence of such planets is by no means proven and several alternative mechanisms have been proposed that could drive similar variations. One of these is apsidal precession, which causes the eclipse times of eccentric binaries to vary sinusoidally on many year time-scales. In this Letter, we present timing data for the secondary eclipse of NN Ser and show that they follow the same trend seen in the primary eclipse times, ruling out apsidal precession as a possible cause for the variations. This result leaves no alternatives to the planetary interpretation for the observed period variations, although we still do not consider their existence as proven. Our data limit the eccentricity of NN Ser to e detect a 3.3 ± 1.0 s delay in the arrival times of the secondary eclipses relative to the best planetary model. This delay is consistent with the expected 2.84 ± 0.04 s Rømer delay of the binary, and is the first time this effect has been detected in a white dwarf plus M dwarf system.

  16. Recubrimiento por láser de aleaciones cuasicristalinas

    Directory of Open Access Journals (Sweden)

    Audebert, F.

    1998-04-01

    Full Text Available Quasicrystals are a new class of ordenated structures with metaestable characteristics at room temperature. Quasicrystalline phases can be obtained by rapid quenching from the melt of some alloys. In general, quasicrystals present properties which make these alloys promising for wear and corrosion resistant coatings applications. During the last years, the development of quasicrystalline coatings by means of thermal spray techniques has been impulsed. However, no references have been found of their application by means of laser techniques. In this work four claddings of quasicrystalline compositions formed over aluminum substrate, produced by a continuos CO2 laser using simultaneous powders mixture injection are presented. The claddings were characterized by X ray diffraction, scanning electron microscopy and Vickers microhardness.

    Los cuasicristales constituyen un nuevo tipo de estructuras ordenadas con características metaestables a temperatura ambiente. En general, en determinadas aleaciones, pueden obtenerse por enfriamiento rápido desde el estado líquido. Han demostrado poseer buenas propiedades para su aplicación como recubrimientos resistentes al desgaste y a la corrosión. En este sentido, desde hace unos años, se ha impulsado el desarrollo de su aplicación mediante técnicas de thermal spray, aunque no se han encontrado referencias de su aplicación mediante técnicas de láser. En este trabajo, se presenta la formación de cuatro recubrimientos de aleaciones con composiciones cuasicristalinas sobre un sustrato de aluminio, utilizando un láser continuo de CO2, con inyección simultánea del material en forma de mezcla de polvos. Los mismos fueron caracterizados por difracción de rayos X, microscopía electrónica de barrido y microdureza Vickers.

  17. Rough surface Au@Ag core-shell nanoparticles to fabricating high sensitivity SERS immunochromatographic sensors.

    Science.gov (United States)

    Fu, Qiangqiang; Liu, Hongwu Liu; Wu, Ze; Liu, An; Yao, Cuize; Li, Xiuqing; Xiao, Wei; Yu, Shiting; Luo, Zhi; Tang, Yong

    2015-11-14

    Immunochromatographic sensors (ICSs) are inexpensive, simple, portable, and robust, thus making ICSs commonplace in clinical diagnoses, food testing, and environmental monitoring. However, commonly used gold nanoparticles (AuNPs) ICSs have low sensitivity. Therefore, we developed highly sensitive surface enhanced Raman scattering (SERS) ICSs. To enhance the sensitivity of SERS ICSs, rough surface core-shell Au@Ag nanoparticles (RSAu@AgNPs) were prepared by coating silver on the surface of gold nanoflowers (AuNFs). Then these nanoparticles were used as SERS substrate in the SERS ICSs, after which the SERS ICSs were implemented to detect haemoglobin and heavy metal cadmium ion (Cd(2+)). The limit of detection (LOD) of the SERS ICSs for detecting haemoglobin was 8 ng/mL, and the linear range of the SERS ICSs was from 31.3 to 2000 ng/mL. The LOD of the SERS ICSs for detecting Cd(2+) was 0.05 ng/mL and the linear analysis range was from 0.05 to 25 ng/mL. The cross reactivity of the SERS ICSs was studied and results showed that the SERS ICSs exhibited highly specific for detection of haemoglobin and Cd(2+), respectively. The SERS ICSs were then used to detect haemoglobin (spiked in serum and in stool) and Cd(2+) (spiked in tap water, river water, and soil leaching water), and the results showed high recovery. These characteristics indicated that SERS ICSs were ideal tools for clinical diagnosis and environmental pollution monitoring.

  18. Ser-634 and Ser-636 of Kaposi’s sarcoma-associated herpesvirus RTA are involved in transactivation and are potential CDK9 phosphorylation sites

    Directory of Open Access Journals (Sweden)

    Wan-Hua eTsai

    2012-02-01

    Full Text Available The replication and transcription activator (RTA of Kaposi’s sarcoma-associated herpesvirus (KSHV, K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity-purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal (527KKRK530 and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ~30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that 634SPSP637 motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ~30% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full

  19. "Ser diferente é normal?"/"Being different: is it normal?"

    Directory of Open Access Journals (Sweden)

    Viviane Veras

    2007-01-01

    Full Text Available A pergunta título deste trabalho retoma o slogan “Ser diferente é normal”, que é parte da campanha criada para uma organização não-governamental que atende portadores de Síndrome de Down. O objetivo é a inclusão social da pessoa com deficiência e o primeiro passo foi propor a inclusão de um grupo de diferentes no grupo dito normal. No vídeo de lançamento da campanha, o diferente, identificado como normal, é mostrado por meio de exemplos – um negro com cabelo black-power, um skin-head, um corpo tatuado, um corpo feminino halterofílico, uma família hippie, uma garota com síndrome de Down. A visão da adolescente dançando reduz, de certo modo, o efeito imaginário que vai além da síndrome, uma vez que apenas o corpo com seus olhinhos puxados se destacam, e não se interrogam questões cognitivas. Minha proposta é refletir sobre o estatuto paradoxal do exemplo, tal como é trabalhado nesse vídeo: se, por definição, um exemplo mostra de fato seu pertencimento a uma classe, pode-se concluir que é exatamente por ser exemplar que ele se encontra fora dela, no exato momento em que a exibe e define. The question in the title of this paper refers to the slogan "ser diferente é normal" ("It´s normal to be different", which is part of a campaign created for a NGO that supports people with Down syndrome. The objective of the campaign is to promote the social inclusion of individuals with Down syndrome, and the first step was to propose the inclusion of a group of "differents" in the so-called normal group. The film launching the campaign shows the different identified as normal by means of examples: a black man exhibiting blackpower haircut, a skin-head, a tattooed body, an over-athletic female body, a hippie family and a girl with Down syndrome. The vision of the dancing teenager lessens the imaginary effect that surpasses the syndrome, since only her body and her little oriental eyes stand out and no cognitive issues are

  20. ¿PERMITE SER FELIZ LA MORAL CRISTIANA?

    Directory of Open Access Journals (Sweden)

    Waldo Romo P

    2006-01-01

    Full Text Available La pregunta que encabeza el artículo ya es desafiante: "¿Permite ser feliz la moral cristiana?". Existe la posibilidad de responder negativamente. El autor, después de analizar algunos pensadores (Nietzsche, entre ellos que han negado a la moral cristiana la posibilidad de hacer feliz al ser humano, presenta las condiciones de posibilidad para que dicha moral se encauce a ser un camino de felicidad. Entre esas condiciones se destaca: el paso de una moral heterónama a una moral de autonomía teónoma, una moral centrada en la persona más que una moral centrada en la ley, una moral de discipulado que pone primero el amor y luego el cumplimiento normativo. Profundiza, al respecto, en el logion de Jesucristo: "El que me ama, cumple mis mandamientos". Esta enseñanza plantea el orden secuencial de toda moral cristiana: porque se ama a Jesús, se entiende el cumplimiento de las normas. Estas se transforman, entonces, en el "test" verificador del amor. De lo contrario, se permanece en un ritualismo normativo, que en defintiva hastía y no lleva a la felicidad. Por ello, el artículo profundiza en una moral de opción fundamental expresada en actitudes y actos morales coherentes con esa opción. Si las condiciones de posibilidad propuestas se llegan a dar, la interrogante que organiza el artículo tendrá una respuesta positivaThe question that heads this article is already challenging: "Does Christian morality permit one to be happy?" The possibility of responding negatively exists. The author, after analyzing the contributions of some thinkers (Nietszche among them who have denied the possibility that Christian morality could make human beings happy, presents the conditions that would orient said morality towards the possibility of becoming a path to happiness. Among those conditions, the author highlights: the passage from a "heteronomous" morality to a morality of "theonomous" autonomy, a morality centered on the person rather than a morality

  1. Surface modification of SERS substrates with plasma-polymerized trimethylsilane nanocoating

    Science.gov (United States)

    Kim, Young Jo; Sun, Xin; Jones, John E.; Lin, Mengshi; Yu, Qingsong; Li, Hao

    2015-03-01

    Surface-enhanced Raman scattering (SERS) substrates were modified by depositing a nanometer-thick polymer coating on top of SERS-active surface. This thin hydrophobic nanocoating, achieved by low temperature plasma polymerization of trimethylsilane, was found to reduce surface energy of SERS substrate and in turn help relieve the analyte spreading on the surface of SERS substrates. Detection of melamine molecules with these surface-modified SERS substrates showed that this plasma nanocoating improved, not significantly though, SERS sensitivity in comparison with unmodified SERS substrates. It is believed that the increased hydrophobicity induced by this plasma nanocoating had two folds of beneficial effects on SERS sensitivity. First, the as-produced hydrophobic surface gave rise to preconcentration effect due to the reduced contact area between analyte molecules and the substrate surface. Second, the decreased surface energy of SERS substrates was helpful in placing analyte molecules in SERS hot spots. These two combined gains were deemed to outweigh the loss of SERS sensitivity caused by enlarged distance between metal surface and analyte molecules.

  2. Balthasar y la metafísica del "ser donado"

    Directory of Open Access Journals (Sweden)

    Carlos Casale

    2009-01-01

    Full Text Available En este artículo se desarrolla la influencia táctica de Heidegger en Hans Urs von Balthasar, especialmente en "La acción". La influencia se ve en dos niveles. Primero de la obra "Ser y tiempo" en la comprensión balthasariana de la temporalidad y finitud, como característica básica -y olvidada a veces- del hombre, que sólo así puede estar abierto a la revelación. El segundo nivel es la obra "Nietzsche" del filósofo de Friburgo. Es sobre todo esta última obra la que le ayuda a Balthasar a pensar a Dios como "acontecimiento", evento gratuito plenificador del hombre. Hay así al interior de la dramática una cierta "analogía" entre la crítica "al olvido del ser" y al "olvido del reconocerse donado", actitud básica del hombre, según Balthasar, frente a la iniciativa de Dios de regalarse, en alteridad, para salvarlo en su temporalidad e historia.In this article, an examination of the tactical influence of Heidegger upon Hans Urs von Balthasar is developed, especially in the theo-drama The Action. This influence is seen on two levels. First, in the work Being and Time on the Balthasarian understanding of temporality and finitude as a basic characteristic -sometimes forgotten- of the human person, who only in this manner can be open to revelation. The second level is the work Nietzsche by the Freiburg philosopher. It is above all this latter work that helps Balthasar to think of God as "event", a gracious fulfilling occurrence of the human person. Thus there exists in the interior of the dramatic a certain "analogy" between the critical "forgetting of being" and the "forgetting of recognizing oneself as given", a basic attitude in the human person, according to Balthasar, when faced with God's initiative of giving Himself as gift, in alterity, in order to save him in his temporality and history.

  3. Optimization of the preparation of glass-coated, dye-tagged metal nanoparticles as SERS substrates.

    Science.gov (United States)

    Brown, Leif O; Doorn, Stephen K

    2008-03-04

    Dye-tagged metal nanoparticles are of significant interest in SERS-based sensitive detection applications. Coating these particles in glass results in an inert spectral tag that can be used in applications such as flow cytometry with significant multiplexing potential. Maximizing the SERS signal obtainable from these particles requires care in partitioning available nanoparticle surface area (binding sites) between the SERS dyes and the functionalized silanes necessary for anchoring the glass coating. In this article, we use the metal-mediated fluorescence quenching of SERS dyes to measure surface areas occupied by both dyes and silanes and thus examine SERS intensities as a function of both dye and silane loading. Notably, we find that increased surface occupation by silane increases the aggregative power of added dye but that decreasing the silane coverage allows a greater surface concentration of dye. Both effects increase the SERS intensity, but obtaining the optimum SERS intensity will require balancing aggregation against surface dye concentration.

  4. Nucleotide sequences of three tRNA(Ser) from Drosophila melanogaster reading the six serine codons.

    Science.gov (United States)

    Cribbs, D L; Gillam, I C; Tener, G M

    1987-10-05

    The nucleotide sequences of three serine tRNAs from Drosophila melanogaster, together capable of decoding the six serine codons, were determined. tRNA(Ser)2b has the anticodon GCU, tRNA(Ser)4 has CGA and tRNA(Ser)7 has IGA. tRNA(Ser)2b differs from the last two by about 25%. However, tRNA(Ser)4 and tRNA(Ser)7 are 96% homologous, differing only at the first position of the anticodon and two other sites. This unusual sequence relationship suggests, together with similar pairs in the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae, that eukaryotic tRNA(Ser)UCN may be undergoing concerted evolution.

  5. Double Detection of Mycotoxins Based on SERS Labels Embedded Ag@Au Core-Shell Nanoparticles.

    Science.gov (United States)

    Zhao, Yuan; Yang, Yaxin; Luo, Yaodong; Yang, Xuan; Li, Manli; Song, Qijun

    2015-10-01

    A sensitive surface-enhanced Raman scattering (SERS) signal dependent double detection of mycotoxins is achieved for the first time, without the aid of nucleic acid amplification strategies. SERS labels embedded Ag@Au core-shell (CS) nanoparticles (NPs) as novel SERS tags are successfully prepared through a galvanic replacement-free deposition. SERS tags produce stable and quantitative SERS signal, emerging from the plasmonic coupling at the junction of Ag core and Au shell. SERS tags engineered Raman aptasensors are developed for the double detection of ochratoxin A (OTA) and aflatoxin B1 (AFB1) in maize meal. The limits of detection (LODs) are as low as 0.006 ng/mL for OTA and 0.03 ng/mL for AFB1. The developed protocol can be extended to a large set of different SERS tags for the sensitive detection of multiple targets that possess different lengths of aptamers.

  6. Timing variations in the secondary eclipse of NN Ser

    CERN Document Server

    Parsons, S G; Bours, M C P; Littlefair, S P; Copperwheat, C M; Dhillon, V S; Breedt, E; Caceres, C; Schreiber, M R

    2013-01-01

    The eclipsing white dwarf plus main-sequence binary NN Serpentis provides one of the most convincing cases for the existence of circumbinary planets around evolved binaries. The exquisite timing precision provided by the deep eclipse of the white dwarf has revealed complex variations in the eclipse arrival times over the last few decades. These variations have been interpreted as the influence of two planets in orbit around the binary. Recent studies have proved that such a system is dynamically stable over the current lifetime of the binary. However, the existence of such planets is by no means proven and several alternative mechanisms have been proposed that could drive similar variations. One of these is apsidal precession, which causes the eclipse times of eccentric binaries to vary sinusoidally on many year timescales. In this paper we present timing data for the secondary eclipse of NN Ser and show that they follow the same trend seen in the primary eclipse times, ruling out apsidal precession as a poss...

  7. A microfluidic dialysis device for complex biological mixture SERS analysis

    KAUST Repository

    Perozziello, Gerardo

    2015-08-01

    In this paper, we present a microfluidic device fabricated with a simple and inexpensive process allowing rapid filtering of peptides from a complex mixture. The polymer microfluidic device can be used for sample preparation in biological applications. The device is fabricated by micromilling and solvent assisted bonding, in which a microdialysis membrane (cut-off of 12-14 kDa) is sandwiched in between an upper and a bottom microfluidic chamber. An external frame connects the microfluidic device to external tubes, microvalves and syringe pumps. Bonding strength and interface sealing are pneumatically tested. Microfluidic protocols are also described by using the presented device to filter a sample composed of specific peptides (MW 1553.73 Da, at a concentration of 1.0 ng/μl) derived from the BRCA1 protein, a tumor-suppressor molecule which plays a pivotal role in the development of breast cancer, and albumin (MW 66.5 kDa, at a concentration of 35 μg/μl), the most represented protein in human plasma. The filtered samples coming out from the microfluidic device were subsequently deposited on a SERS (surface enhanced Raman scattering) substrate for further analysis by Raman spectroscopy. By using this approach, we were able to sort the small peptides from the bigger and highly concentrated protein albumin and to detect them by using a label-free technique at a resolution down to 1.0 ng/μl.

  8. SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

    Energy Technology Data Exchange (ETDEWEB)

    Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

    2009-05-06

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  9. Peculiarities of the SEHRS and SERS Spectra of - Bipyridine Molecule

    CERN Document Server

    Chelibanov, Vladimir P; Polubotko, Aleksey M

    2016-01-01

    The SEHRS and SERS spactra of 4,4 - Bipyridine are analyzed on the base of the Dipole-Quadrupole theory for two possible geometries of the molecule. It is demonstrated that there appear strong lines caused by vibrations transforming after a unit irreducible representation both for the geometry with D2 and D2h symmetry groups, which may probably describe the symmetry properties of the molecule. Appearance of these lines is associated with a strong quadrupole light-molecule interaction, which arises in nano size rregions of sharp roughness of the metal. In addition, there are the lines caused by contributions from both the vibrations transforming after the unit irredicible representations A or Ag and the representations B1 or B1u, respectively, which describe transformational properties of the Ez component of the dipole moment, which is perpendicular to the surface for both geometries. This result is associated with a specific geometry of the molecule, when the indicated vibrations can be nearly degenerated and...

  10. Fotografia: viajar, ver e ser visto na internet

    Directory of Open Access Journals (Sweden)

    Anabel S. Cavalcanti

    2011-02-01

    Full Text Available

    Este artigo pretende tratar da fotografia – especialmente turística – como meio de ver e ser visto, numa visão antropológica das Teorias da Imagem. O valor dado às memórias e à identidade familiar nos tradicionais álbuns de família é transferido à exposição virtual na rede mundial de computadores, facilitada pelas novas tecnologias. Mais do que aproveitar as viagens turísticas, na contemporaneidade se quer mostrar que viajou. E para isso não existe melhor caminho do que fotografar-se e exibir-se na internet.


  11. Flower bouquet variation in four species of Crocus ser. Verni.

    Science.gov (United States)

    Carta, Angelino; Flamini, Guido; Cioni, Pier Luigi; Pistelli, Luisa; Peruzzi, Lorenzo

    2015-01-01

    Flowering plants employ a wide variety of signals, including scent, to attract pollinators. The aim of this work was to examine whether flower volatiles in four closely related Crocus species are linked to species divergence and to the current knowledge on their pollination syndromes. Fragrances of freshly opened flowers in Crocus etruscus, C. ilvensis, C. neglectus, and C. vernus, all belonging to ser. Verni, were analyzed using GC/MS. Results coincide with present knowledge about systematic relationships among taxa. The four species fall into two main fragrance types, based on similarities of their volatile compounds. In C. etruscus, C. ilvensis, and C. neglectus, oxygenated monoterpenes (lilac aldehyde B and A) are most abundant, while C. vernus has a fragrance rich in monoterpene hydrocarbons (α-pinene and limonene). Our results point towards outcrossing mating strategies for C. etruscus, C. ilvensis, and C. neglectus, whose volatile compounds are known as pollinator attractants. This is in line with their flower architecture, showing a style of variable height, often overtopping stamens. On the other hand, a self-pollination strategy was repeatedly suggested in the literature for C. vernus, marked by flowers with the style deeply inserted in the stamens and also by a completely different flower bouquet.

  12. SDS bubbles functionalized with Gold nanoparticles and SERS applications

    Science.gov (United States)

    Navarro-Badilla, A.; Hurtado, R. Britto; Cortez-Valadez, M.; Perez-Rodriguez, A.; Flores-Acosta, M.; Maldonado-Arce, A.

    2017-03-01

    We present a method of incorporation of gold nanoparticles in SDS (sodium dodecyl sulfate) bubbles with a low polydispersity index (monodispersed nanoparticles). Both the bubbles and nanoparticles maintained their structural and morphologic properties after functionalization. The bubbles present a radio of 0.38 mm with a standard deviation of±0.018 mm. The gold nanoparticles were obtained with sucrose as the catalytic agent and ascorbic acid as the reducing agent. The nanoparticles display several geometric morphologies as well as sizes inferior to 50 nm, as observed in the images obtained with Transmission Electron Microscopy (TEM). The optical properties were studied by optical absorption spectroscopy. The absorption band linked to the surface plasmon resonance (SPR) is located at 550 nm before and after the functionalization of the bubbles. Moreover, microscopic bubbles with a diameter smaller than 1 μm with the ability to stabilize nanoparticles in their surface were found in isolated regions of the sample. Additionally, the Surface Enhancement Raman Spectroscopy (SERS) properties of the colloid were analyzed with common drugs.

  13. Juan O’Gorman. Formas de no ser arquitecto

    Directory of Open Access Journals (Sweden)

    Javier Jerez González

    2015-12-01

    Full Text Available La obra proyectada y construida por Juan O’Gorman a lo largo de su vida traza un recorrido largo y sincopado entre formas de entender la arquitectura totalmente antagónicas. Su primera etapa de radical racionalismo desarrolla, según procedimientos estrictamente técnicos, un lenguaje revolucionario basado en la austeridad y la precisión. A pesar de ello muchas de sus obras destacan por la plasticidad de sus composiciones volumétricas, la riqueza espacial o, incluso, por la creación de atmósferas oníricas. Los primeros años de frenética actividad dan paso a un periodo de voluntario alejamiento de la práctica profesional de la arquitectura: ni una sola obra, ni un solo proyecto durante cerca de 15 años. Tan solo su actividad docente le mantiene en contacto con el mundo de la arquitectura. Cuando Juan O’Gorman vuelve a ejercer como arquitecto, lo hace construyendo algunos de los iconos del movimiento de integración plástica de México: la biblioteca central de la UNAM y su casa en San Jerónimo. A pesar de las enormes diferencias, o más bien oposiciones, entre unos momentos y otros, puede identificarse una invariante clara como señal de identidad personal: una velada voluntad de no ser arquitecto

  14. Em Busca de um Ser Humano Não Programado

    Directory of Open Access Journals (Sweden)

    John Schranz

    2014-05-01

    Full Text Available Stanislavski diz a seus atores: o Estúdio é para a Vida. Meyerhold acrescenta: o Teatro é a arte do Homem. Craig prevê um novo ator: Hoje ele personifica e interpreta; amanhã ele precisará representar e interpretar, e no terceiro dia ele irá criar. Grotowski e Barba aproveitam as forças do teatro oriental na epifania do Performer. Finalmente suprimindo a dependência do autor para criar a partir de si mesmo, o novo Performer obtém autonomia artística. Além disso: ao contrário de outros artistas, ele cria através de si mesmo, sem o uso de um meio. O papel do Diretor pressupõe uma fase intermediária: sem a base estável e unificadora do texto do Autor a autonomia arduamente adquirida pelo Performer poderia degenerar-se em individualismo centrado no ego. Segundo a neurociência, a ação precede a consciência. Fora de seu ato criativo como artista e dentro dele como matéria-prima, o Performer desafia limites. Ele é um sujeito-objeto, uma busca pelo Ser Humano não programado.

  15. Fasting mediated increase in p-BAD(ser155) and p-AKT(ser473) in the prefrontal cortex of mice.

    Science.gov (United States)

    Pitchaimani, Vigneshwaran; Arumugam, Somasundaram; Thandavarayan, Rajarajan Amirthalingam; Karuppagounder, Vengadeshprabhu; Sreedhar, Remya; Afrin, Rejina; Harima, Meilei; Suzuki, Hiroshi; Miyashita, Shizuka; Nomoto, Mayumi; Sone, Hirohito; Suzuki, Kenji; Watanabe, Kenichi

    2014-09-05

    BAD-deficient mice and fasting have several common functional roles in seizures, beta-hydroxybutyrate (BHB) uptake in brain and alteration in counterregulatory hormonal regulation during hypoglycemia. Neuronal specific insulin receptor knockout (NIRKO) mice display impaired counterregulatory hormonal responses during hypoglycemia. In this study we investigated the fasting mediated expression of p-BAD(ser155) and p-AKT(ser473) in different regions of brain (prefrontal cortex, hippocampus, midbrain and hypothalamus). Fasting specifically increases p-BAD(ser155) and p-AKT(ser473) in prefrontal cortex and decreases in other regions of brain. Our results suggest that fasting may increase the uptake BHB by decreasing p-BAD(ser155) in the brain during hypoglycemia except prefrontal cortex and it uncovers specific functional area of p-BAD(ser155) and p-AKT(ser473) that may regulates counter regulatory hormonal response. Overall in support with previous findings, fasting mediated hypoglycemia activates prefrontal cortex insulin signaling which influences the hypothalamic paraventricular nucleus mediated activation of sympathoadrenal hormonal responses.

  16. Industrial Applications of the Surface-Enhanced Raman Spectroscopy Application industrielle du SERS

    Directory of Open Access Journals (Sweden)

    Nabiev I.

    2006-11-01

    Full Text Available Surface-enhanced Raman scattering (SERS spectroscopy is now a well-established phenomenon, which has been thoroughly characterized in a variety of interfacial and colloidal environments. Although some quantitative aspects of the underlying enhancement mechanisms apparently remain unresolved, attention is now shifting towards application of SERS to explore phenomena of chemical, physical, biological and industrial significance. The goal of this review is to appreciate the industrial value of innovative SERS technique on the basis of our experience in development of new SERS-active substrates and in their biomedical and biotechnological applications. Examples of diverse SERS analytical applications as well as some very recent facilities, as SERS microprobe analysis, SERS fiber optics probes, FT-SERS spectroscopy, SERS detection for high-performance liquid chromatography, etc. , are also discussed. Le SERS (Surface Enhanced Raman Spectroscopy est un phénomène aujourd'hui bien connu qui a été étudié dans toute une gamme de milieux interfaciaux et colloïdaux. Si certains aspects quantitatifs des mécanismes d'exaltation restent apparemment non résolus, l'attention se porte à présent vers l'application de la spectroscopie SERS à l'exploration de phénomènes présentant un intérêt chimique, physique, biologique et industriel. L'objectif de cet article est d'estimer la valeur industrielle des nouvelles techniques de spectroscopie SERS à partir de notre expérience dans le développement de nouveaux substrats actifs en SERS et leurs applications biomédicales et biotechnologiques. Les auteurs discutent également des exemples de diverses applications analytiques de la spectroscopie SERS ainsi que de quelques procédés très récents : analyse par microsonde SERS, sondes SERS à fibres optiques, spectroscopie FT-SERS, détection SERS pour la chromatographie haute performance en phase liquide, etc.

  17. Loss of p53 Ser18 and Atm results in embryonic lethality without cooperation in tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Heather L Armata

    Full Text Available Phosphorylation at murine Serine 18 (human Serine 15 is a critical regulatory process for the tumor suppressor function of p53. p53Ser18 residue is a substrate for ataxia-telangiectasia mutated (ATM and ATM-related (ATR protein kinases. Studies of mice with a germ-line mutation that replaces Ser18 with Ala (p53(S18A mice have demonstrated that loss of phosphorylation of p53Ser18 leads to the development of tumors, including lymphomas, fibrosarcomas, leukemia and leiomyosarcomas. The predominant lymphoma is B-cell lymphoma, which is in contrast to the lymphomas observed in Atm(-/- animals. This observation and the fact that multiple kinases phosphorylate p53Ser18 suggest Atm-independent tumor suppressive functions of p53Ser18. Therefore, in order to examine p53Ser18 function in relationship to ATM, we analyzed the lifespan and tumorigenesis of mice with combined mutations in p53Ser18 and Atm. Surprisingly, we observed no cooperation in survival and tumorigenesis in compound p53(S18A and Atm(-/- animals. However, we observed embryonic lethality in the compound mutant animals. In addition, the homozygous p53Ser18 mutant allele impacted the weight of Atm(-/- animals. These studies examine the genetic interaction of p53Ser18 and Atm in vivo. Furthermore, these studies demonstrate a role of p53Ser18 in regulating embryonic survival and motor coordination.

  18. Role of Ser7 phosphorylation of the CTD during transcription of snRNA genes

    Science.gov (United States)

    Egloff, Sylvain

    2012-01-01

    The largest subunit of RNA polymerase (pol) II, Rpb1, contains an unusual carboxyl-terminal domain (CTD) composed of consecutive repeats of the sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser (Y1S2P3T4S5P6S7). During transcription, Ser2, Ser5 and Ser7 are subjected to dynamic phosphorylation and dephosphorylation by CTD kinases and phosphatases, creating a characteristic CTD phosphorylation pattern along genes. This CTD “code” allows the coupling of transcription with co-transcriptional RNA processing, through the timely recruitment of the appropriate factors at the right point of the transcription cycle. In mammals, phosphorylation of Ser7 (Ser7P) is detected on all pol II-transcribed genes, but is only essential for expression of a sub-class of genes encoding small nuclear (sn)RNAs. The molecular mechanisms by which Ser7P influences expression of these particular genes are becoming clearer. Here, I discuss our recent findings clarifying how Ser7P facilitates transcription of these genes and 3′end processing of the transcripts, through recruitment of the RPAP2 phosphatase and the snRNA gene-specific Integrator complex. PMID:22858677

  19. The IkappaB kinase family phosphorylates the Parkinson's disease kinase LRRK2 at Ser935 and Ser910 during Toll-like receptor signaling.

    Directory of Open Access Journals (Sweden)

    Nicolas Dzamko

    Full Text Available Mutations in leucine-rich repeat kinase 2 (LRRK2 are strongly associated with late-onset autosomal dominant Parkinson's disease. LRRK2 is highly expressed in immune cells and recent work points towards a link between LRRK2 and innate immunity. Here we demonstrate that stimulation of the Toll-Like Receptor (TLR pathway by MyD88-dependent agonists in bone marrow-derived macrophages (BMDMs or RAW264.7 macrophages induces marked phosphorylation of LRRK2 at Ser910 and Ser935, the phosphorylation sites that regulate the binding of 14-3-3 to LRRK2. Phosphorylation of these residues is prevented by knock-out of MyD88 in BMDMs, but not the alternative TLR adaptor protein TRIF. Utilising both pharmacological inhibitors, including a new TAK1 inhibitor, NG25, and genetic models, we provide evidence that both the canonical (IKKα and IKKβ and IKK-related (IKKε and TBK1 kinases mediate TLR agonist induced phosphorylation of LRRK2 in vivo. Moreover, all four IKK members directly phosphorylate LRRK2 at Ser910 and Ser935 in vitro. Consistent with previous work describing Ser910 and Ser935 as pharmacodynamic biomarkers of LRRK2 activity, we find that the TLR independent basal phosphorylation of LRRK2 at Ser910 and Ser935 is abolished following treatment of macrophages with LRRK2 kinase inhibitors. However, the increased phosphorylation of Ser910 and Ser935 induced by activation of the MyD88 pathway is insensitive to LRRK2 kinase inhibitors. Finally, employing LRRK2-deficient BMDMs, we present data indicating that LRRK2 does not play a major role in regulating the secretion of inflammatory cytokines induced by activation of the MyD88 pathway. Our findings provide the first direct link between LRRK2 and the IKKs that mediate many immune responses. Further work is required to uncover the physiological roles that phosphorylation of LRRK2 by IKKs play in controlling macrophage biology and to determine how phosphorylation of LRRK2 by IKKs impacts upon the use of Ser

  20. SER Y ACCIÓN SOCIAL EN EL HORIZONTE DE LA REFLEXIÓN ACERCA DEL TIEMPO DESARROLLADA POR HEIDEGGER EN SER Y TIEMPO

    OpenAIRE

    Domingo Fernández Agis

    2014-01-01

    Según plantea Heidegger en Ser y tiempo, la pregunta por el ser no es fruto de la espontaneidad de la llamada conciencia natural, aunque tampoco en la racionalidad científica pueda encontrar los elementos adecuados para su formulación. Sabemos, en todo caso, que la ciencia puede contribuir a la respuesta, aunque no ayude a comprender lo que el hecho mismo de esa enunciación implica. La tesis que se defiende en este trabajo es que la correlación entre la pregunta por el ser y la pregunta por e...

  1. Ser e não ser gente: dinâmicas da feitiçaria no alto Xingu

    Directory of Open Access Journals (Sweden)

    Marina Vanzolini

    2013-08-01

    Full Text Available Baseado em uma pesquisa de campo com os Aweti, grupo tupi do alto Xingu, o artigo propõe uma reflexão sobre as particularidades da agressão mágica xinguana no cenário amazônico, relacionando técnicas, campos de incidência e efeitos políticos de tais práticas. Contrariando uma imagem corrente na etnologia regional, os xinguanos sempre identificam a fonte de seus maiores sofrimentos com a ação de pessoas bastante próximas, frequentemente coaldeãos da vítima, e sempre outros xinguanos, isto é, integrantes do que Ellen Basso denominou de "comunidade moral" xinguana: um conjunto multiétnico de aliados que se define, idealmente, pela abdicação da violência entre si. A hipótese central deste trabalho é que a feitiçaria xinguana deveria ser pensada como parte de um mecanismo de produção de inimizade que, operando a partir das relações cotidianas, faz com que o esforço histórico de produção de identidade comunitária pareça nunca se completar.

  2. Large-Scale Hot Spot Engineering for Quantitative SERS at the Single-Molecule Scale.

    Science.gov (United States)

    Chen, Hung-Ying; Lin, Meng-Hsien; Wang, Chun-Yuan; Chang, Yu-Ming; Gwo, Shangjr

    2015-10-28

    Quantitative surface enhanced Raman spectroscopy (SERS) requires precise control of Raman enhancement factor and detection uniformity across the SERS substrate. Here, we show that alkanethiolate ligand-regulated silver (Ag) nanoparticle films can be used to achieve quantitative SERS measurements down to the single-molecule level. The two-dimensional hexagonal close-packed superlattices of Ag nanoparticles formed in these films allow for SERS detection over a large area with excellent uniformity and high Raman enhancement factor. In particular, the SERS signal from the thiolate ligands on Ag nanoparticle surfaces can be utilized as a stable internal calibration standard for reproducible quantitative measurements. We demonstrate the capability of quantitative SERS by measuring the areal densities of crystal violet molecules embedded in an ultrathin spin-on-glass detection "hot zone", which is a planar and uniformly enhanced region several nanometers above the Ag nanoparticles. The Raman measurement results exhibit a linear response over a wide dynamic range of analyte concentration.

  3. Novel bottom-up SERS substrates for quantitative and parallelized analytics.

    Science.gov (United States)

    Strelau, Katharina K; Schüler, Thomas; Möller, Robert; Fritzsche, Wolfgang; Popp, Jürgen

    2010-02-01

    Surface-enhanced Raman spectroscopy (SERS) is an emerging technology in the field of analytics. Due to the high sensitivity in connection with specific Raman molecular fingerprint information SERS can be used in a variety of analytical, bioanalytical, and biosensing applications. However, for the SERS effect substrates with metal nanostructures are needed. The broad application of this technology is greatly hampered by the lack of reliable and reproducible substrates. Usually the activity of a given substrate has to be determined by time-consuming experiments such as calibration or ultramicroscopic studies. To use SERS as a standard analytical tool, cheap and reproducible substrates are required, preferably with a characterization technique that does not interfere with the subsequent measurements. Herein we introduce an innovative approach to produce low-cost and large-scale reproducible substrates for SERS applications, which allows easy and economical production of micropatterned SERS active surfaces on a large scale. This approach is based on an enzyme-induced growth of silver nanostructures. The special structural feature of the enzymatically deposited silver nanoparticles prevents the breakdown of SERS activity even at high particle densities (particle density >60%) that lead to a conductive layer. In contrast to other approaches, this substrate exhibits a relationship between electrical conductivity and the resulting SERS activity of a given spot. This enables the prediction of the SERS activity of the nanostructure ensemble and therewith the controllable and reproducible production of SERS substrates of enzymatic silver nanoparticles on a large scale, utilizing a simple measurement of the electrical conductivity. Furthermore, through a correlation between the conductivity and the SERS activity of the substrates it is possible to quantify SERS measurements with these substrates.

  4. El ser humano y sus posibilidades de construcción desde el cuidado

    Directory of Open Access Journals (Sweden)

    Alacoque Lorenzini Erdmann

    2003-01-01

    Full Text Available El artículo presenta algunas concepciones del ser humano en relación con el cuidado de enfermería. A partir de la organización de la vida se establecen relaciones, interacciones del ser humano, sus límites y posibilidades para el cuidado con la vida, con lo cotidiano y con la naturaleza. Resalta la importancia y el compromiso en la construcción colectiva del ser ciudadano.

  5. Surface Enhanced Raman Scattering (SERS) Detection of Ammonium Nitrate (AN) Samples Fabricated Using Drop-on-Demand Inkjet Technology on Commercial and Fabricated SERS Substrates

    Science.gov (United States)

    2013-04-01

    Holthoff, E. L.; Stratis-Cullum, D. N.; Hankus, M. E. A Nanosensor for TNT Detection Based on Molecularly Imprinted Polymers and Surface Enhanced Raman...excitation employed, and produces a narrowband spectral signature unique to the 2 molecular vibrations of the analyte. Since the discovery of SERS in...using a simple one-step direct imprinting process, thus, creating a porous gold grating film that has previously been shown to contribute to a SERS

  6. Assignment of vibrational spectral bands of kidney tissue by means of low temperature SERS spectroscopy

    Science.gov (United States)

    Velicka, M.; Radzvilaite, M.; Ceponkus, J.; Urboniene, V.; Pucetaite, M.; Jankevicius, F.; Steiner, G.; Sablinskas, V.

    2017-02-01

    Surface enhanced Raman scattering (SERS) spectroscopy is a useful method for detection of trace amounts of molecules. It has already been successfully implemented for detection of explosives, food additives, biomarkers in blood or urine, etc. In the last decade, SERS spectroscopy was introduced into the field of health sciences and has been especially focused on early disease detection. In the recent years, application of SERS spectroscopy for detection of various types of human cancerous tissues emerged. Furthermore, SERS spectroscopy of extracellular fluid shows great potential for the differentiation of normal and cancerous tissues; however, due to high variety of molecules present in such biological samples, the experimental spectrum is a combination of many different overlapping vibrational spectral bands. Thus, precise assignment of these bands to the corresponding molecular vibrations is a difficult task. In most cases, researchers try to avoid this task satisfying just with tentative assignment. In this study, low temperature SERS measurements of extracellular fluid of cancerous and healthy kidney tissue samples were carried out in order to get a deeper understanding of the nature of vibrational spectral bands present in the experimental spectrum. The SERS spectra were measured in temperature range from 300 K down to 100 K. SERS method was implemented using silver nanoparticle colloidal solution. The results of the low temperature SERS experiment were analysed and compared with the results of theoretical calculations. The analysis showed that the SERS spectrum of extracellular fluid of kidney tissue is highly influenced by the vibrational bands of adenine and Lcystine molecules.

  7. Vibrational fingerprinting of bacterial pathogens by surface enhanced Raman scattering (SERS)

    Science.gov (United States)

    Premasiri, W. Ranjith; Moir, D. T.; Ziegler, Lawrence D.

    2005-05-01

    The surface enhanced Raman scattering (SERS) spectra of vegetative whole-cell bacteria were obtained using in-situ grown gold nanoparticle cluster-covered silicon dioxide substrates excited at 785 nm. SERS spectra of Gram-negative bacteria; E. coli and S. typhimurium, and Gram-positive bacteria; B. subtilis, B. cereus, B. thuringeinsis and B. anthracis Sterne, have been observed. Raman enhancement factors of ~104-105 per cell are found for both Gram positive and Gram negative bacteria on this novel SERS substrate. The bacterial SERS spectra are species specific and exhibit greater species differentiation and reduced spectral congestion than their corresponding non-SERS (bulk) Raman spectra. Fluorescence observed in the 785 nm excited bulk Raman emission of Bacillus species is not apparent in the corresponding SERS spectra. The surface enhancement effect allows the observation of Raman spectra at the single cell level excited by low incident laser powers (blood serum, has an observable effect on the bacterial SERS spectra. However, reproducible, species specific SERS vibrational fingerprints are still obtained. The potential of SERS for detection and identification of bacteria with species specificity on these gold nanoparticle coated substrates is demonstrated by these results.

  8. Sensitive SERS nanotags for use with a hand-held 1064 nm Raman spectrometer

    Science.gov (United States)

    Kearns, Hayleigh; Ali, Fatima; Bedics, Matthew A.; Shand, Neil C.; Faulds, Karen; Detty, Michael R.; Graham, Duncan

    2017-07-01

    This is the first report of the use of a hand-held 1064 nm Raman spectrometer combined with red-shifted surface-enhanced Raman scattering (SERS) nanotags to provide an unprecedented performance in the short-wave infrared (SWIR) region. A library consisting of 17 chalcogenopyrylium nanotags produce extraordinary SERS responses with femtomolar detection limits being obtained using the portable instrument. This is well beyond previous SERS detection limits at this far red-shifted wavelength and opens up new options for SERS sensors in the SWIR region of the electromagnetic spectrum (between 950 and 1700 nm).

  9. Graphene-Plasmonic Hybrid Platform for Label-Free SERS Biomedical Detection

    Science.gov (United States)

    Wang, Pu

    Surface Enhanced Raman Scattering (SERS) has attracted explosive interest for the wealth of vibrational information it provides with minimal invasive effects to target analyte. Nanotechnology, especially in the form of noble metal nanoparticles exhibit unique electromagnetic and chemical characteristics that are explored to realize ultra-sensitive SERS detection in chemical and biological analysis. Graphene, atom-thick carbon monolayer, exhibits superior chemical stability and bio-compatibility. A combination of SERS-active metal nanostructures and graphene will create various synergies in SERS. The main objective of this research was to exploit the applications of the graphene-Au tip hybrid platform in SERS. The hybrid platform consists of a periodic Au nano-pyramid substrate to provide reproducible plasmonic enhancement, and the superimposed monolayer graphene sheet, serving as "built-in" Raman marker. Extensive theoretical and experimental studies were conducted to determine the potentials of the hybrid platform as SERS substrate. Results from both Finite-Domain Time-Domain (FDTD) numerical simulation and Raman scattering of graphene suggested that the hybrid platform boosted a high density of hotspots yielding 1000 times SERS enhancement of graphene bands. Ultra-high sensitivity of the hybrid platform was demonstrated by bio-molecules including dye, protein and neurotransmitters. Dopamine and serotonin can be detected and distinguished at 10-9 M concentration in the presence of human body fluid. Single molecule detection was obtained using a bi-analyte technique. Graphene supported a vibration mode dependent SERS chemical enhancement of ˜10 to the analyte. Quantitative evaluation of hotspots was presented using spatially resolved Raman mapping of graphene SERS enhancement. Graphene plays a crucial role in quantifying SERS hotspots and paves the path for defining SERS EF that could be universally applied to various SERS systems. A reproducible and statistically

  10. TLC-SERS Plates with a Built-In SERS Layer Consisting of Cap-Shaped Noble Metal Nanoparticles Intended for Environmental Monitoring and Food Safety Assurance

    Directory of Open Access Journals (Sweden)

    H. Takei

    2015-01-01

    Full Text Available We report on a thin layer chromatograph (TLC with a built-in surface enhanced Raman scattering (SERS layer for in-situ identification of chemical species separated by TLC. Our goal is to monitor mixture samples or diluted target molecules suspended in a host material, as happens often in environmental monitoring or detection of food additives. We demonstrate that the TLC-SERS can separate mixture samples and provide in-situ SERS spectra. One sample investigated was a mixture consisting of equal portions of Raman-active chemical species, rhodamine 6 G (R6G, crystal violet (CV, and 1,2-di(4-pyridylethylene (BPE. The three components could be separated and their SERS spectra were obtained from different locations. Another sample was skim milk with a trace amount of melamine. Without development, no characteristic peaks were observed, but after development, a peak was observed at 694 cm−1. Unlike previous TLC-SERS whereby noble metal nanoparticles are added after development of a sample, having a built-in SERS layer greatly facilitates analysis as well as maintaining high uniformity of noble metal nanoparticles.

  11. El deber ser de la auditoría

    Directory of Open Access Journals (Sweden)

    Omar de Jesús Montilla Galvis

    2006-01-01

    Full Text Available No falta mucho tiempo para asistir a la integración de las sociedades de la Tierra, a llegar a lo que algunos denominan “aldea global”. No podemos detener los cambios, u oponernos a ellos con la idea de que si les somos indiferentes y no les damos importancia no suceden. Las naciones se vienen transformando multidimensionalmente, no es sólo la tecnología, ni los nichos de mercado, nilas formas de producción, ni la competencia en las economías liberadas, es uncambio en la manera cognoscitiva de pensar y actuar en el mundo de hoy. La auditoría es una práctica de trascendental importancia social y económica, permite entablar relaciones de diversa índole entre los agentes económicos, debido a la confianza que se deposita en el trabajo de los contadores públicos cuando ellos extienden su garantía personal o fe pública, respecto del trabajo de investigación denominado auditoría. Es respecto al conocimiento sobre la auditoría que el presente artículo propone hacerle frente a la necesidad de cambio, las adaptaciones y transformaciones con las que sobreviven las especies, la auditoría se ve en grave riesgo de ser absorbida por otras profesiones, motivo por el cual es necesario comenzar un proceso de adaptación para que sobreviva como una práctica propia de los contadores públicos. La adaptación propuesta tiene como finla evolución de la auditoría, “articulando” toda la información derivada del desarrollo del objeto social de las organizaciones para realizar gestión del conocimiento en las mismas, de este modo convertir dicho conocimiento en la ventaja competitiva más importante de la organización. No es posible esperar que la auditoría continúe con las ideas de su génesis antes de la era cristiana, o con los cambios sufridos a causa de la gran depresión, la responsabilidad de la auditoría ahora tiene que ver con el mejoramiento dela sociedad como efecto del cambio de las organizaciones. Es hora de romper el statu quo

  12. Development of surface enhanced Raman scattering (SERS) spectroscopy monitoring of fuel markers to prevent fraud

    Science.gov (United States)

    Wilkinson, Timothy; Clarkson, John; White, Peter C.; Meakin, Nicholas; McDonald, Ken

    2013-05-01

    Governments often tax fuel products to generate revenues to support and stimulate their economies. They also subsidize the cost of essential fuel products. Fuel taxation and subsidization practices are both subject to fraud. Oil marketing companies also suffer from fuel fraud with loss of legitimate sales and additional quality and liability issues. The use of an advanced marking system to identify and control fraud has been shown to be effective in controlling illegal activity. DeCipher has developed surface enhanced Raman scattering (SERS) spectroscopy as its lead technology for measuring markers in fuel to identify and control malpractice. SERS has many advantages that make it highly suitable for this purpose. The SERS instruments are portable and can be used to monitor fuel at any point in the supply chain. SERS shows high specificity for the marker, with no false positives. Multiple markers can also be detected in a single SERS analysis allowing, for example, specific regional monitoring of fuel. The SERS analysis from fuel is also quick, clear and decisive, with a measurement time of less than 5 minutes. We will present results highlighting our development of the use of a highly stable silver colloid as a SERS substrate to measure the markers at ppb levels. Preliminary results from the use of a solid state SERS substrate to measure fuel markers will also be presented.

  13. Influence of the OGG1 Ser326Cys polymorphism on oxidatively damaged DNA and repair activity

    DEFF Research Database (Denmark)

    Jensen, Annie; Løhr, Mille; Eriksen, Louise;

    2012-01-01

    of the comet assay. We collected blood samples from 1,019 healthy subjects and genotyped for the OGG1 Ser326Cys polymorphism. We found 49 subjects homozygous for the variant genotype (Cys/Cys) and selected same numbers of age-matched subjects with the heterozygous (Ser/Cys) and homozygous wild-type genotype...

  14. A Study of Relationship Between Universality in Fractal Colloids Aggregation and Time-dependent SERS

    Institute of Scientific and Technical Information of China (English)

    张宏光; 刘凡镇; 何天敬; 辛厚文

    1994-01-01

    The relationship between the rule of time-dependent surface-enhanced Raman scattering (SERS) intensity of adsorbed pyridine in AgBr sol and silver bromide colloidal fractal aggregation is studied in this paper. The experimental results support the view of universality in colloidal aggregation and suggest that SERS may be a useful tool in the study of kinetics of colloidal aggregation.

  15. CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER COATING LAYER FOR POLYMER FILM

    Institute of Scientific and Technical Information of China (English)

    Xiao-ning Liu; Gi Xue; Yun Lu; Jun Zhang; Fen-ting Li; Chen-chen Xue; Stephen Z.D. Cheng

    2001-01-01

    When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surfaceenhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

  16. SERS-Activated Platforms for Immunoassay: Probes, Encoding Methods, and Applications.

    Science.gov (United States)

    Wang, Zhuyuan; Zong, Shenfei; Wu, Lei; Zhu, Dan; Cui, Yiping

    2017-06-28

    Owing to their excellent multiplexing ability, high sensitivity, and large dynamic range, immunoassays using surface-enhanced Raman scattering (SERS) as the readout signal have found prosperous applications in fields such as disease diagnosis, environmental surveillance, and food safety supervision. Various ever-increasing demands have promoted SERS-based immunoassays from the classical sandwich-type ones to those integrated with fascinating automatic platforms (e.g., test strips and microfluidic chips). As recent years have witnessed impressive progress in SERS immunoassays, we try to comprehensively cover SERS-based immunoassays from their basic working principles to specific applications. Focusing on several basic elements in SERS immunoassays, typical structures of SERS nanoprobes, productive optical spectral encoding strategies, and popular immunoassay platforms are highlighted, followed by their representative biological applications in the last 5 years. Moreover, despite the vast advances achieved to date, SERS immunoassays still suffer from some annoying shortcomings. Thus, proposals on how to improve the SERS immunoassay performance are also discussed, as well as future challenges and perspectives, aiming to give brief and valid guidelines for choosing suitable platforms according to particular applications.

  17. Following the Dynamics of pH in Endosomes of Live Cells with SERS Nanosensors

    DEFF Research Database (Denmark)

    Kneipp, J.; Kneipp, Harald; Wittig, B.

    2010-01-01

    The surface enhanced Raman scattering (SERS) spectrum of a reporter molecule attached to gold or silver nanostructures, which is pH-sensitive, can deliver information on the local pH in the environment of the nanostructure. Here, we demonstrate the use of a mobile SERS nanosensor made from gold...

  18. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

    Science.gov (United States)

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-04-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

  19. Gold dimer nanoantenna with slanted gap for tunable LSPR and improved SERS

    KAUST Repository

    Kessentini, Sameh

    2014-02-13

    We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method-taking into account periodicity, adhesion layer, and roughness-is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated. © 2014 American Chemical Society.

  20. Aromatic amino acids providing characteristic motifs in the Raman and SERS spectroscopy of peptides.

    Science.gov (United States)

    Wei, Fang; Zhang, Dongmao; Halas, Naomi J; Hartgerink, Jeffrey D

    2008-07-31

    Raman and surface-enhanced Raman spectroscopies (SERS) are potentially important tools in the characterization of biomolecules such as proteins and DNA. In this work, SERS spectra of three cysteine-containing aromatic peptides: tryptophan-cysteine, tyrosine-cysteine, and phenylalanine-cysteine, bound to Au nanoshell substrates, were obtained, and compared to their respective normal Raman spectra. While the linewidths of the SERS peaks are significantly broadened (up to 70%), no significant spectral shifts (features in the Raman and SERS spectra of peptides and proteins when present. It follows that the Raman modes of these three small constructed peptides may likely apply to the assignment of Raman and SERS features in the spectra of other peptides and proteins.

  1. Non-labeling multiplex surface enhanced Raman scattering (SERS) detection of volatile organic compounds (VOCs)

    DEFF Research Database (Denmark)

    Wong, Chi Lok; Dinish, U. S.; Schmidt, Michael Stenbæk

    2014-01-01

    In this paper, we report multiplex SERS based VOCs detection with a leaning nano-pillar substrate. The VOCs analyte molecules adsorbed at the tips of the nano-pillars produced SERS signal due to the field enhancement occurring at the localized surface plasmon hot spots between adjacent leaning nano...... chemical sensing layer for the enrichment of gas molecules on sensor surface. The leaning nano-pillar substrate also showed highly reproducible SERS signal in cyclic VOCs detection, which can reduce the detection cost in practical applications. Further, multiplex SERS detection on different combination...... of acetone and ethanol vapor was also successfully demonstrated. The vibrational fingerprints of molecular structures provide specific Raman peaks for different VOCs contents. To the best of our knowledge, this is the first multiplex VOCs detection using SERS. We believe that this work may lead to a portable...

  2. Development of SERS substrate using phage-based magnetic template for triplex assay in sepsis diagnosis.

    Science.gov (United States)

    Nguyen, Anh H; Shin, Yesol; Sim, Sang Jun

    2016-11-15

    Development of a new substrate for surface-enhanced Raman scattering (SERS) is one area of interest for the improvement of SERS performance. Herein, we introduce a new method for developing new mesoporous SERS substrates using M13 phages that display cysteine-rich peptides on the pVIII major units, which is an alternative for thiol donor using chemical modifications. Together with the SERS substrate development, and the use of the SERS technique for sepsis diagnostics is a new approach in clinical settings. The substrates were characterized and magnetized with magnetic immuno colloids made of gold-coated magnetic nanoparticles and specific antibodies. Conventionally, the SERS-tags are prepared by using gold nanoparticles and are modified with Raman dyes to immobilize specific antibodies to capture the biomarkers in the serum samples. However, in this method the SERS-tags are bound to the mesoporous substrate via antibody/antigen interactions to form clusters or layer-by-layer assemblies of SERS-tags for Raman signal enhancement. The SERS spectra showed distinct peaks for tags corresponding to three typical sepsis-specific biomarkers for diagnostics with the limit of detection values of 27 pM, 103 pM, and 78 pM for C-reactive protein (CRP), procalcitonin (PCT), and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), respectively. With such an approach, SERS can be used for clinical purposes and can be improved by phage display modification rather than chemical alternatives. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. SERS Label Method and its Application in the Biochemical Analysis%SERS 标记方法在生化分析中的应用

    Institute of Scientific and Technical Information of China (English)

    刘建芝; 朱桂池; 胡勇军

    2015-01-01

    Surface-enhanced Raman scattering (SERS)label method is a novel bioassay technology,which combines the modern bio-label technology and SERS spectroscopy.In present method,the signal of the Raman report mole cules, acting as the label tracer signal,is enhanced by adsorbing on the noble metal (i.e.Ag and Au)nanoparticles.With the advantages of high sensitivity,high specificity,fast and easy detection in biochemical analysis,the study on SERS label method has been a hot topic.Here,SERS labeling method has been introduced firstly and its applications recently in the labeled immunoassay,tumor targeting,DNA molecular recognition and microbiological detection have been reviewed.At last,future prospect in this field are indicated.%表面增强拉曼散射(SERS)标记方法结合现代生物标记方法与 SERS 光谱技术,使吸附到金或银等贵金属表面的标记分子的拉曼信号显著增强,并将其作为标记示踪信号,具有生物兼容性好、灵敏度高、分子特征性强和快速简便等优点,已成为新颖的标记示踪技术的研究热点之一。本文综述近年来 SERS 标记技术应用于基因分析、蛋白质检测、微生物检测、肿瘤靶向和小分子物质的最新进展,着重介绍蛋白质和小分子物质的检测,并展望了今后的发展方向。

  4. Cyanuric acid hydrolase from Azorhizobium caulinodans ORS 571: crystal structure and insights into a new class of Ser-Lys dyad proteins.

    Directory of Open Access Journals (Sweden)

    Seunghee Cho

    Full Text Available Cyanuric acid hydrolase (CAH catalyzes the hydrolytic ring-opening of cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, an intermediate in s-triazine bacterial degradation and a by-product from disinfection with trichloroisocyanuric acid. In the present study, an X-ray crystal structure of the CAH-barbituric acid inhibitor complex from Azorhizobium caulinodans ORS 571 has been determined at 2.7 Å resolution. The CAH protein fold consists of three structurally homologous domains forming a β-barrel-like structure with external α-helices that result in a three-fold symmetry, a dominant feature of the structure and active site that mirrors the three-fold symmetrical shape of the substrate cyanuric acid. The active site structure of CAH is similar to that of the recently determined AtzD with three pairs of active site Ser-Lys dyads. In order to determine the role of each Ser-Lys dyad in catalysis, a mutational study using a highly sensitive, enzyme-coupled assay was conducted. The 10⁹-fold loss of activity by the S226A mutant was at least ten times lower than that of the S79A and S333A mutants. In addition, bioinformatics analysis revealed the Ser226/Lys156 dyad as the only absolutely conserved dyad in the CAH/barbiturase family. These data suggest that Lys156 activates the Ser226 nucleophile which can then attack the substrate carbonyl. Our combination of structural, mutational, and bioinformatics analyses differentiates this study and provides experimental data for mechanistic insights into this unique protein family.

  5. Fabrication of SERS swab for direct detection of trace explosives in fingerprints.

    Science.gov (United States)

    Gong, Zhengjun; Du, Hongjie; Cheng, Fansheng; Wang, Cong; Wang, Canchen; Fan, Meikun

    2014-12-24

    Swab sampling is of great importance in surface contamination analysis. A cotton swab (cotton Q-tip) was successfully transformed into surface-enhanced Raman scattering (SERS) substrate (SERS Q-tip) through a bottom-up strategy, where Ag NPs were first self-assembled onto the Q-tip followed by in situ growing. The capability for direct swab detection of Raman probe Nile Blue A (NBA) and a primary explosive marker 2,4-dinitrotoluene (2,4-DNT) using the SERS Q-tip was explored. It was found that at optimum conditions, a femotogram of NBA on glass surface could be swab-detected. The lowest detectable amount for 2,4-DNT is only ∼1.2 ng/cm(2) (total amount of 5 ng) on glass surface, 2 orders of magnitude more sensitive than similar surface analysis achieved with infrared technique, and comparable even with that obtained by ion mobility spectrometry-mass spectrometry. Finally, 2,4-DNT left on fingerprints was also analyzed. It was found that SERS signal of 2,4-DNT from 27th fingerprint after touching 2,4-DNT powder can still be clearly identified by swabbing with the SERS Q-tip. We believe this is the first direct SERS swabbing test of explosives on fingerprint on glass. Considering its relative long shelf life (>30 d), the SERS Q-tip may find great potential in future homeland security applications when combined with portable Raman spectrometers.

  6. Apoptotic phosphorylation of histone H3 on Ser-10 by protein kinase Cδ.

    Directory of Open Access Journals (Sweden)

    Choon-Ho Park

    Full Text Available Phosphorylation of histone H3 on Ser-10 is regarded as an epigenetic mitotic marker and is tightly correlated with chromosome condensation during both mitosis and meiosis. However, it was also reported that histone H3 Ser-10 phosphorylation occurs when cells are exposed to various death stimuli, suggesting a potential role in the regulation of apoptosis. Here we report that histone H3 Ser-10 phosphorylation is mediated by the pro-apoptotic kinase protein kinase C (PKC δ during apoptosis. We observed that PKCδ robustly phosphorylates histone H3 on Ser-10 both in vitro and in vivo. Ectopic expression of catalytically active PKCδ efficiently induces condensed chromatin structure in the nucleus. We also discovered that activation of PKCδ is required for histone H3 Ser-10 phosphorylation after treatment with DNA damaging agents during apoptosis. Collectively, these findings suggest that PKCδ is the kinase responsible for histone H3 Ser-10 phosphoryation during apoptosis and thus contributes to chromatin condensation together with other apoptosis-related histone modifications. As a result, histone H3 Ser-10 phosphorylation can be designated a new 'apoptotic histone code' mediated by PKCδ.

  7. Preparation of sensitive and recyclable porous Ag/TiO2 composite films for SERS detection

    Science.gov (United States)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe

    2015-12-01

    Porous Ag/TiO2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO2 films. The highest SERS sensitivity that allowed as low as 10-10 M aqueous CV to be detected, was achieved with the PEG/(C4H9O)4Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10-10 to 10-5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  8. Tunable coating of gold nanostars: tailoring robust SERS labels for cell imaging

    Science.gov (United States)

    Bassi, B.; Taglietti, A.; Galinetto, P.; Marchesi, N.; Pascale, A.; Cabrini, E.; Pallavicini, P.; Dacarro, G.

    2016-07-01

    Surface modification of noble metal nanoparticles with mixed molecular monolayers is one of the most powerful tools in nanotechnology, and is used to impart and tune new complex surface properties. In imaging techniques based on surface enhanced Raman spectroscopy (SERS), precise and controllable surface modifications are needed to carefully design reproducible, robust and adjustable SERS nanoprobes. We report here the attainment of SERS labels based on gold nanostars (GNSs) coated with a mixed monolayer composed of a poly ethylene glycol (PEG) thiol (neutral or negatively charged) that ensure stability in biological environments, and of a signalling unit 7-Mercapto-4-methylcoumarin as a Raman reporter molecule. The composition of the coating mixture is precisely controlled using an original method, allowing the modulation of the SERS intensity and ensuring overall nanoprobe stability. The further addition of a positively charged layer of poly (allylamine hydrocloride) on the surface of negatively charged SERS labels does not change the SERS response, but it promotes the penetration of GNSs in SH-SY5Y neuroblastoma cells. As an example of an application of such an approach, we demonstrate here the internalization of these new labels by means of visualization of cell morphology obtained with SERS mapping.

  9. Role of Porphyromonas gingivalis SerB in Gingival Epithelial Cell Cytoskeletal Remodeling and Cytokine Production▿

    Science.gov (United States)

    Hasegawa, Yoshiaki; Tribble, Gena D.; Baker, Henry V.; Mans, Jeffrey J.; Handfield, Martin; Lamont, Richard J.

    2008-01-01

    The SerB protein of Porphyromonas gingivalis is a HAD family serine phosphatase that plays a critical role in entry and survival of the organism in gingival epithelial cells. SerB is secreted by P. gingivalis upon contact with epithelial cells. Here it is shown by microarray analysis that SerB impacts the transcriptional profile of gingival epithelial cells, with pathways involving the actin cytoskeleton and cytokine production among those significantly overpopulated with differentially regulated genes. Consistent with the transcriptional profile, a SerB mutant of P. gingivalis exhibited defective remodeling of actin in epithelial cells. Interaction between gingival epithelial cells and isolated SerB protein resulted in actin rearrangement and an increase in the F/G actin ratio. SerB protein was also required for P. gingivalis to antagonize interleukin-8 accumulation following stimulation of epithelial cells with Fusobacterium nucleatum. SerB is thus capable of modulating host cell signal transduction that impacts the actin cytoskeleton and cytokine production. PMID:18391005

  10. Role of Porphyromonas gingivalis SerB in gingival epithelial cell cytoskeletal remodeling and cytokine production.

    Science.gov (United States)

    Hasegawa, Yoshiaki; Tribble, Gena D; Baker, Henry V; Mans, Jeffrey J; Handfield, Martin; Lamont, Richard J

    2008-06-01

    The SerB protein of Porphyromonas gingivalis is a HAD family serine phosphatase that plays a critical role in entry and survival of the organism in gingival epithelial cells. SerB is secreted by P. gingivalis upon contact with epithelial cells. Here it is shown by microarray analysis that SerB impacts the transcriptional profile of gingival epithelial cells, with pathways involving the actin cytoskeleton and cytokine production among those significantly overpopulated with differentially regulated genes. Consistent with the transcriptional profile, a SerB mutant of P. gingivalis exhibited defective remodeling of actin in epithelial cells. Interaction between gingival epithelial cells and isolated SerB protein resulted in actin rearrangement and an increase in the F/G actin ratio. SerB protein was also required for P. gingivalis to antagonize interleukin-8 accumulation following stimulation of epithelial cells with Fusobacterium nucleatum. SerB is thus capable of modulating host cell signal transduction that impacts the actin cytoskeleton and cytokine production.

  11. eenagers Want to be Mothers... But... Las adolescentes quieren ser madres... pero... Adolescentes desejam ser mães… mas…

    Directory of Open Access Journals (Sweden)

    DURÁN DE VILLALOBOS MARÍA MERCEDES

    2010-10-01

    entrevistas a profundidad a 30 adolescentes gestantes, Del análisis emergieron siete categorías: “Embarazo inesperado”, “Asumiendo el embarazo”, “Experimentando formas de cuidarse”, “Padeciendo pérdidas por el embarazo”, “Culpándose por el embarazo”, “Resistiéndose al aborto” y “Reedificando redes de apoyo”. Emerge la categoría central y por ende el planteamiento hipotético afirmando que las adolescentes están “Deseando el embarazo pero no tan pronto”. Se parte del concepto ambivalencia como hilo conductor para mostrar cómo evoluciona esta secuencia de acciones/interacciones en respuesta a la experiencia del embarazo y cómo se alinean según las condiciones y cambios que han experimentado en su contexto también ambivalente.

    Se concluye que las adolescentes embarazadas delegan en el hombre la protección frente a un posible embarazo, sin embargo, cuando se enteran de estar embarazadas los excluyen y excusan de cualquier responsabilidad. Asocian cuidado con cambios en sus comportamientos sociales sin ser significativos los cambios físicos. El 21% de las participantes, están pasando por su segundo embarazo, indicador alarmante para el bienestar de estas jóvenes y sus hijos por nacer. La relación padres-adolescente se afianza durante el embarazo, aunque sus madres cuando tuvieron conocimiento de que sus hijas ya habían iniciado su actividad sexual, lo ignoraron. Se hace un llamado urgente a innovar estrategias de cuidado individualizado y contextualizado.

    Este estudo foi realizado com base teórica e objetivou o seguinte: descrever a experiência de gravidez e gerar uma hipótese sobre esse processo em um grupo de adolescentes; coletar dados através de entrevistas em profundidade realizadas em 30 adolescentes grávidas.

    Sete categorias surgiram da analise: “Gravidez inesperada”; “Assumindo a gravidez”, “Experimentando métodos de prevenção”,

  12. Teenagers Want to be Mothers... But... Las adolescentes quieren ser madres... pero... Adolescentes desejam ser mães… mas…

    Directory of Open Access Journals (Sweden)

    VIRGINIA INÉS SOTO LESMES

    2010-10-01

    álisis emergieron siete categorías: "Embarazo inesperado", "Asumiendo el embarazo", "Experimentando formas de cuidarse", "Padeciendo pérdidas por el embarazo", "Culpándose por el embarazo", "Resistiéndose al aborto" y "Reedificando redes de apoyo". Emerge la categoría central y por ende el planteamiento hipotético afirmando que las adolescentes están "Deseando el embarazo pero no tan pronto". Se parte del concepto ambivalencia como hilo conductor para mostrar cómo evoluciona esta secuencia de acciones/interacciones en respuesta a la experiencia del embarazo y cómo se alinean según las condiciones y cambios que han experimentado en su contexto también ambivalente. Se concluye que las adolescentes embarazadas delegan en el hombre la protección frente a un posible embarazo, sin embargo, cuando se enteran de estar embarazadas los excluyen y excusan de cualquier responsabilidad. Asocian cuidado con cambios en sus comportamientos sociales sin ser significativos los cambios físicos. El 21% de las participantes, están pasando por su segundo embarazo, indicador alarmante para el bienestar de estas jóvenes y sus hijos por nacer. La relación padres-adolescente se afianza durante el embarazo, aunque sus madres cuando tuvieron conocimiento de que sus hijas ya habían iniciado su actividad sexual, lo ignoraron. Se hace un llamado urgente a innovar estrategias de cuidado individualizado y contextualizado.Este estudo foi realizado com base teórica e objetivou o seguinte: descrever a experiência de gravidez e gerar uma hipótese sobre esse processo em um grupo de adolescentes; coletar dados através de entrevistas em profundidade realizadas em 30 adolescentes grávidas. Sete categorias surgiram da analise: "Gravidez inesperada"; "Assumindo a gravidez", "Experimentando métodos de prevenção", "Sofrendo perdas pela gravidez", "Sentindo culpa pela gravidez", "Rejeitando o aborto" e "Reconstruindo redes de apoio". Surge a categoria central e, portanto, a hipótese afirmando que as

  13. Phospho-Bcl-xL(Ser62) influences spindle assembly and chromosome segregation during mitosis.

    Science.gov (United States)

    Wang, Jianfang; Beauchemin, Myriam; Bertrand, Richard

    2014-01-01

    Functional analysis of a series of phosphorylation mutants reveals that Bcl-xL(Ser62Ala) influences cell entry into anaphase and mitotic exit in taxol-exposed cells compared with cells expressing wild-type Bcl-xL or a series of other phosphorylation mutants, an effect that appears to be independent of its anti-apoptotic activity. During normal mitosis progression, Bcl-xL(Ser62) is strongly phosphorylated by PLK1 and MAPK14/SAPKp38α at the prometaphase, metaphase, and the anaphase boundaries, while it is de-phosphorylated at telophase and cytokinesis. Phospho-Bcl-xL(Ser62) localizes in centrosomes with γ-tubulin and in the mitotic cytosol with some spindle-assembly checkpoint signaling components, including PLK1, BubR1, and Mad2. In taxol- and nocodazole-exposed cells, phospho-Bcl-xL(Ser62) also binds to Cdc20- Mad2-, BubR1-, and Bub3-bound complexes, while Bcl-xL(Ser62Ala) does not. Silencing Bcl-xL expression and expressing the phosphorylation mutant Bcl-xL(Ser62Ala) lead to an increased number of cells harboring mitotic spindle defects including multipolar spindle, chromosome lagging and bridging, aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h. Together, the data indicate that during mitosis, Bcl-xL(Ser62) phosphorylation impacts on spindle assembly and chromosome segregation, influencing chromosome stability. Observations of mitotic cells harboring aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h were also made with cells expressing the phosphorylation mutant Bcl-xL(Ser49Ala) and dual mutant Bcl-xL(Ser49/62Ala).

  14. Passive mass transport for direct and quantitative SERS detection using purified silica encapsulated metal nanoparticles

    Science.gov (United States)

    Shrestha, Binaya Kumar

    This thesis focuses on understanding implications of nanomaterial quality control and mass transport through internally etched silica coated nanoparticles for direct and quantitative molecular detection using surface enhanced Raman scattering (SERS). Prior to use, bare nanoparticles (partially or uncoated with silica) are removal using column chromatography to improve the quality of these nanomaterials and their SERS reproducibility. Separation of silica coated nanoparticles with two different diameters is achieved using Surfactant-free size exclusion chromatography with modest fractionation. Next, selective molecular transport is modeled and monitored using SERS and evaluated as a function of solution ionic strength, pH, and polarity. Molecular detection is achieved when the analytes first partition through the silica membrane then interact with the metal surface at short distances (i.e., less than 2 nm). The SERS intensities of unique molecular vibrational modes for a given molecule increases as the number of molecules that bind to the metal surface increases and are enhanced via both chemical and electromagnetic enhancement mechanisms as long as the vibrational mode has a component of polarizability tensor along the surface normal. SERS signals increase linearly with molecular concentration until the three-dimensional SERS-active volume is saturated with molecules. Implications of molecular orientation as well as surface selection rules on SERS intensities of molecular vibrational modes are studied to improve quantitative and reproducible SERS detection using internally etched Ag Au SiO2 nanoparticles. Using the unique vibrational modes, SERS intensities for p-aminothiophenol as a function of metal core compositions and plasmonics are studied. By understanding molecular transport mechanisms through internally etched silica matrices coated on metal nanoparticles, important experimental and materials design parameters are learned, which can be subsequently applied

  15. Long-term stable silver subsurface ion-exchanged glasses for SERS applications.

    Science.gov (United States)

    Simo, Anne; Joseph, Virginia; Fenger, Robert; Kneipp, Janina; Rademann, Klaus

    2011-06-20

    We report on the formation of silver subsurface ion-exchanged metal oxide (silver SIMO) glasses and their surface-enhanced Raman scattering (SERS) activity. The samples were prepared by a combined thermal and chemical three-step methodology and characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental electron scanning microscopy (ESEM), and UV/Vis spectroscopy. This unique method provides SERS substrates with protection against contamination and strong, reliable and reproducible SERS enhancement. The Raman enhancement factors of the long-term stable SIMO glasses were estimated to approximately 10(7).

  16. Paper SERS chromatography for detection of trace analytes in complex samples

    Science.gov (United States)

    Yu, Wei W.; White, Ian M.

    2013-05-01

    We report the application of paper SERS substrates for the detection of trace quantities of multiple analytes in a complex sample in the form of paper chromatography. Paper chromatography facilitates the separation of different analytes from a complex sample into distinct sections in the chromatogram, which can then be uniquely identified using SERS. As an example, the separation and quantitative detection of heroin in a highly fluorescent mixture is demonstrated. Paper SERS chromatography has obvious applications, including law enforcement, food safety, and border protection, and facilitates the rapid detection of chemical and biological threats at the point of sample.

  17. Recent progress in the fabrication of SERS substrates based on the arrays of polystyrene nanospheres

    Science.gov (United States)

    Zhang, XiaoLei; Dai, ZhiGao; Zhang, XinGang; Dong, ShiLian; Wu, Wei; Yang, ShiKuan; Xiao, XiangHeng; Jiang, ChangZhong

    2016-12-01

    Micro/nanostructures have broad applications in diverse application fields, such as surface enhanced Raman spectroscopy (SERS), photocatalysis, field emission, photonic crystals, microfluidic devices, electrochemical devices, etc. Using polystyrene (PS) spheres formed monolayer colloidal crystal templates as masks, scaffolds, or molds with different materials growth techniques, many different periodic nanostructured arrays can be obtained with the building units varied from nanoparticles, nanopores, nanorings, nanorods, to nanoshells. Significant progresses have been made on the synthesis of micro/nanostructures with efficient SERS response. In this review, we mainly focus on the various PS template-based fabrication techniques in realizing micro/nanostructured arrays and the SERS applications.

  18. Numerical study on the mechanisms of the SERS of gold-coated pyramidal tip substrates

    Science.gov (United States)

    Li, Rui; Wang, Qiao; Li, Hong; Liu, Kun; Pan, Shi; Zhan, Weishen; Chen, Maodu

    2016-06-01

    In this paper, the physical enhancement mechanisms of the surface-enhanced Raman scattering (SERS) of pyramidal tip substrates are studied theoretically. We structure the periodic square-based arrays of adjacent nanometer pyramidal gold-coated tips on silicon. In order to determine the contribution of plasmonic or diffraction effects on the SERS, three-dimensional (3D) numerical simulations are implemented by taking into account the substrate coated with a gold thin film or a perfect electrical conductor thin film. The tip distance, metal coating thickness and incident light polarization angle are also optimized to investigate whether the further SERS signal can be enhanced.

  19. Aplicaciones de tratamientos de refundido láser en aleaciones metálicas.

    OpenAIRE

    2016-01-01

    Este trabajo de investigación se ha centrado en investigar la tecnología láser como tratamiento de fusión superficial de materiales metálicos, así como analizar las posibles mejoras en sus propiedades. El objetivo concreto del presente trabajo ha sido analizar el empleo de los tratamientos de endurecimiento láser en aleaciones metálicas. Además se ha realizado un procedimiento experimental de a tres muestras con un láser de diodo de alta potencia.

  20. ser y terapia fotodinámica en el tratamiento del acné

    OpenAIRE

    2009-01-01

    De la realización del presente estudio, en le que describimos nuestra experiencia sobre el empleo de láser y terapia fotodinámica en el tratamiento del acné, se extraen las siguientes conclusiones: La terapia fotodinámica, mediante el empleo de mtilaminolevulinato (MAL) y láser de colorante pulsado de pulso largo (LP PDL), es un tratamiento efectivo para el acné de predominio inflamatorio. La terapia fotodinámica en el tratamiento del acné puede ser considerada una técnica inocua dada la prác...

  1. Visiones sobre la alteridad: la lectura sartreana de Ser y tiempo

    OpenAIRE

    Szeftel, Micaela

    2011-01-01

    Al abordar el estudio del Para-otro en El Ser y la Nada, Sartre reconoce la astucia que Heidegger tuvo al haber enunciado la “realidad-humana” como una relación de ser. La oposición entre sujeto y objeto, en la cual las teorías del conocimiento encuentran no sólo el fundamento del existir humano sino también el punto de partida para la pregunta por el ser, es reemplazada por un vínculo fundado en una esfera pre-ontológica. Mientras que Sartre considera que tanto Hegel como Husserl han quedado...

  2. Concepción de ser humano detrás de la Quinta Disciplina

    OpenAIRE

    Roldan Tomasz Suárez Litvin

    2010-01-01

    El presente ensayo expone el modo de ser de un ser humano promovido por la Quinta Disciplina de Peter Senge. Luego de un breve resumen de sus principales postulados, se destaca el modo como los mismos apuntan hacia una forma de humanidad y de relación entre el ámbito individual y el organizacional inconsistente con el esquema de pensamiento social moderno. Seguidamente se muestra que esta concepción no-moderna de ser humano guarda ciertas semejanzas con aquella propia de la cultura griega ant...

  3. La Linguistica Aplicada a la Relacion Paradigmatica entre los Verbos "Ser" y "Estar" (Linguistics Applied to the Paradigmatic Relationship between the Verbs "Ser" and "Estar")

    Science.gov (United States)

    Marchetti, Magda Ruggeri

    1977-01-01

    Speakers of Italian often have problems mastering Spanish because they erroneously believe its great similiarity to Italian makes it easy to learn. One of the fundamental problems is the lack of ability to choose the correct verb, "ser" or "estar," both equivalents of the Italian "essere." (Text is in Spanish.) (CFM)

  4. La Linguistica Aplicada a la Relacion Paradigmatica entre los Verbos "Ser" y "Estar" (Linguistics Applied to the Paradigmatic Relationship between the Verbs "Ser" and "Estar")

    Science.gov (United States)

    Marchetti, Magda Ruggeri

    1977-01-01

    Speakers of Italian often have problems mastering Spanish because they erroneously believe its great similiarity to Italian makes it easy to learn. One of the fundamental problems is the lack of ability to choose the correct verb, "ser" or "estar," both equivalents of the Italian "essere." (Text is in Spanish.) (CFM)

  5. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    Science.gov (United States)

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-03-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations.

  6. La luminosa sed: Esbozo de un itinerario de la manifestación del ser como deseo de ser al Dios deseante que viene a nuestro encuentro

    Directory of Open Access Journals (Sweden)

    Alberto Toutin

    2009-01-01

    Full Text Available En este artículo se presenta un primer atisbo de un itinerario de pensamiento que busca articular, por un lado, una comprensión de la poesía en Octavio Paz como manifestación del ser humano como apertura al otro, como deseo de ser y, por otro, la comprensión en Hans Urs von Balthasar del acontecimiento de la automanifestación de Dios, como expresión de su deseo de encuentro con el ser humano y que para ello adopta arriesgada y creativamente su lenguaje en la diversidad de sus expresiones. Con ello tan sólo queremos poner algunas bases para una poética teológica, ya iniciada tanto por Dios como por el hablar del ser humano, y que llama de ella misma a ser continuada y profundizada.In this article, the author presents a first glimpse of an itinerary of thought that seeks to articulate, on the one hand, an understanding of poetry by Octavio Paz as a manifestation of the human being as openness to the other and as desire for being and, on the other hand, Hans Urs von Balthasar's understanding of the event of God's self-manifestation as the expression of His desire to meet the human being and, to that end, adopting, with risk and creativity, the human being's language in all the diversity of its expressions. With that, the author only wants to lay some foundations for a theological poetics, already initiated as much by God as by the speech of the human being, and which calls from its own self to be continuous and deepened.

  7. P-Ser-HPr-a link between carbon metabolism and the virulence of some pathogenic bacteria

    DEFF Research Database (Denmark)

    Mijakovic, Ivan

    2005-01-01

    HPr kinase/phosphorylase phosphorylates HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system, at serine-46. P-Ser-HPr is the central regulator of carbon metabolism in Gram-positive bacteria, but also plays a role in virulence development of certain...... pathogens. In Listeria monocytogenes, several virulence genes, which depend on the transcription activator PrfA, are repressed by glucose, fructose, etc., in a catabolite repressor (CcpA)-independent mechanism. However, the catabolite co-repressor P-Ser-HPr was found to inhibit the activity of Prf...... is probably also mediated via P-Ser-HPr, since ccpA disruption leads to elevated amounts of P-Ser-HPr. Indeed, a ccpA ptsH1 double mutant exhibited normal PrfA activity. In S. pyogenes, the expression of several virulence genes depends on the transcription activator Mga. Interestingly, the mga promoter...

  8. Nanoreplicated positive and inverted sub-micron polymer pyramids array for surface enhanced Raman spectroscopy (SERS)

    CERN Document Server

    Xu, Zhida

    2014-01-01

    We demonstrate gold coated polymer surface enhanced Raman scattering (SERS) substrates with a pair of complementary structures--positive and inverted pyramids array structures fabricated by multiple-step molding and replication process. The uniform SERS enhancement factors over the entire device surfaces were measured as 7.2 X 10^4 for positive pyramids substrate while 1.6 X 10^6 for inverted pyramids substrate with Rhodamine 6G as the target analyte. Based on the optical reflection measurement and FDTD simulation result, the enhancement factor difference is attributed to plasmon resonance matching and to SERS "hot spots ". With this simple, fast and versatile complementary molding process, we can produce polymer SERS substrates with extremely low cost, high throughput and high repeatability.

  9. “el ser y el tiempo”, de heidegger continuación (1)

    OpenAIRE

    2011-01-01

    Al hacer la pregunta por el ser, hay que fijar el ente que funciona como primario para formularla; también se requiere establecer la forma recta de acceso a dicho ente.  Entonces, este toma el principal papel en la pregunta.  El" ser ahí" -cada uno de nosotros mismos- es el ente que tiene la preerninenciaóntica y ontológica para hacer la pregunta. Ónticamente es lo más cercano, pero ontológicamente lo más lejano; de la proximidad  proviene la distancia, ya que el "ser ahí", el ser en el mundo...

  10. Reliable Quantitative SERS Analysis Facilitated by Core-Shell Nanoparticles with Embedded Internal Standards.

    Science.gov (United States)

    Shen, Wei; Lin, Xuan; Jiang, Chaoyang; Li, Chaoyu; Lin, Haixin; Huang, Jingtao; Wang, Shuo; Liu, Guokun; Yan, Xiaomei; Zhong, Qiling; Ren, Bin

    2015-06-15

    Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-molecule-shell nanoparticles with two components in the molecular layer, a framework molecule to form the shell, and a probe molecule as a Raman internal standard, were rationally designed for quantitative SERS analysis. The signal of the embedded Raman probe provides effective feedback to correct the fluctuation of samples and measuring conditions. Meanwhile, target molecules with different affinities can be adsorbed onto the shell. The quantitative analysis of target molecules over a large concentration range has been demonstrated with a linear response of the relative SERS intensity versus the surface coverage, which has not been achieved by conventional SERS methods.

  11. Crystal structure of selenolate-protected Au24(SeR)20 nanocluster.

    Science.gov (United States)

    Song, Yongbo; Wang, Shuxin; Zhang, Jun; Kang, Xi; Chen, Shuang; Li, Peng; Sheng, Hongting; Zhu, Manzhou

    2014-02-26

    We report the X-ray structure of a selenolate-capped Au24(SeR)20 nanocluster (R = C6H5). It exhibits a prolate Au8 kernel, which can be viewed as two tetrahedral Au4 units cross-joined together without sharing any Au atoms. The kernel is protected by two trimeric Au3(SeR)4 staple-like motifs as well as two pentameric Au5(SeR)6 staple motifs. Compared to the reported gold-thiolate nanocluster structures, the features of the Au8 kernel and pentameric Au5(SeR)6 staple motif are unprecedented and provide a structural basis for understanding the gold-selenolate nanoclusters.

  12. Examining metal nanoparticle surface chemistry using hollow-core, photonic-crystal, fiber-assisted SERS.

    Science.gov (United States)

    Eftekhari, Fatemeh; Lee, Anna; Kumacheva, Eugenia; Helmy, Amr S

    2012-02-15

    In this Letter, we demonstrate the efficacy of hollow core photonic crystal fibers (HCPCFs) as a surface-enhanced Raman spectroscopy (SERS) platform for investigating the ligand exchange process on the surface of gold nanoparticles. Raman measurements carried out using this platform show the capability to monitor minute amounts of surface ligands on gold nanoparticles used as an SERS substrate. The SERS signal from an HCPCF exhibits a tenfold enhancement compared to that in a direct sampling scheme using a cuvette. Using exchange of cytotoxic cetyltrimethylammonium bromide with α-methoxy-ω-mercaptopoly(ethylene glycol) on the surface of gold nanorods as an exemplary system, we show the feasibility of using HCPCF SERS to monitor the change in surface chemistry of nanoparticles.

  13. Label free detection of DNA on Au/ZnO/Ag hybrid structure based SERS substrate

    Science.gov (United States)

    Pal, Anil Kumar; Mohan, D. Bharathi

    2016-04-01

    Au/ZnO/Ag based SERS substrate was fabricated for the label free detection of DNA of Escherichia Coli bacteria. The SERS substrate was fabricated by growing ZnO nanorod arrays on thermally evaporated ultrathin Ag film of 5 nm thickness using hydrothermal process. Non-spherical like Au nanoparticles were decorated on ZnO nanorod arrays by sputtering technique with sputtering time of 45 sec. The surface of Au/ZnO/Ag was observed to be nearly superhydrophobic exhibiting the contact angle of 144 °. A low volume (5 µl) of aqueous solution of DNA of laboratory strain Escherichia Coli with very low concentration was adsorbed on fabricated SERS substrate by drop casting. The SERS detection of DNA molecules was achieved up to lower concentration of 10-8 M due to strong local electric field enhancement at the nanometer gap among Au nanoparticles and superhydrophobic nature of Au/ZnO/Ag surface.

  14. Selective detection of 1000 B. anthracis spores within 15 minutes using a peptide functionalized SERS assay.

    Science.gov (United States)

    Farquharson, Stuart; Shende, Chetan; Smith, Wayne; Huang, Hermes; Inscore, Frank; Sengupta, Atanu; Sperry, Jay; Sickler, Todd; Prugh, Amber; Guicheteau, Jason

    2014-12-21

    A surface-enhanced Raman spectroscopy (SERS) assay has been designed to detect Bacillus anthracis spores. The assay consists of silver nanoparticles embedded in a porous glass structure that have been functionalized with ATYPLPIR, a peptide developed to discriminately bind B. anthracis versus other species of Bacillus. Once bound, acetic acid was used to release the biomarker dipicolinic acid from the spores, which was detected by SERS through the addition of silver colloids. This SERS assay was used to selectively bind B. anthracis with a 100-fold selectivity versus B. cereus, and to detect B. anthracis Ames at concentrations of 1000 spores per mL within 15 minutes. The SERS assay measurements provide a basis for the development of systems that can detect spores collected from the air or from water supplies.

  15. Surface Enhanced Raman Scattering (SERS Studies of Gold and Silver Nanoparticles Prepared by Laser Ablation

    Directory of Open Access Journals (Sweden)

    Samuel P. Hernandez-Rivera

    2013-03-01

    Full Text Available Gold and silver nanoparticles (NPs were prepared in water, acetonitrile and isopropanol by laser ablation methodologies. The average characteristic (longer size of the NPs obtained ranged from 3 to 70 nm. 4-Aminobenzebethiol (4-ABT was chosen as the surface enhanced Raman scattering (SERS probe molecule to determine the optimum irradiation time and the pH of aqueous synthesis of the laser ablation-based synthesis of metallic NPs. The synthesized NPs were used to evaluate their capacity as substrates for developing more analytical applications based on SERS measurements. A highly energetic material, TNT, was used as the target compound in the SERS experiments. The Raman spectra were measured with a Raman microspectrometer. The results demonstrate that gold and silver NP substrates fabricated by the methods developed show promising results for SERS-based studies and could lead to the development of micro sensors.

  16. Novel SERS materials for multiplex biomolecular detection via controlled nanoparticle linking and polymer encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Braun, G B; Lee, S J; Laurence, T; Fera, N; Fabris, L; Bazan, G C; Moskovits, M; Reich, N O

    2008-07-21

    Over the past decade the emphasis on single-molecule sensitivity of surface-enhanced Raman spectroscopy (SERS) has brought to prominence the special role played by so-called SERS 'hot spots', oftentimes nanometer-scale junctions between nanostructures. In this report, optimally SERS enhancing silver clusters were synthesized using bifunctional linkers and polymer and/or protein encapsulation. The synthesis, which results in stable clusters even when stored for months or dried and re-dissolved, is scalable to large quantities. Using a sacrificial linker approach we also employ a permeable polymer/protein shell for general small molecule sensing. Finally, we utilize these nanomaterials by tagging specific epitopes on cancer cells and show that SERS signals from single clusters can be measured routinely.

  17. SERS imaging of cell-surface biomolecules metabolically labeled with bioorthogonal Raman reporters.

    Science.gov (United States)

    Xiao, Ming; Lin, Liang; Li, Zefan; Liu, Jie; Hong, Senlian; Li, Yaya; Zheng, Meiling; Duan, Xuanming; Chen, Xing

    2014-08-01

    Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbondeuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging.

  18. Multidimensional Co3O4 nano sponge for the highly sensitive SERS applications

    Science.gov (United States)

    Zhao, Miao-miao; Liu, Wen-yao; Du, Jian-gong; Guo, Xu-dong; Wang, Lei; Xia, Mei-jing; Tang, Jun

    2017-01-01

    In this work, surface enhanced Raman spectroscopy (SERS) substrates with Ag nanoparticles (NPs) decorated Co3O4 nanowires (NWs) grafted on the three-dimensional (3D) network architecture of Ni foam (denoted as Ag-NP@Co3O4-NW/Ni-foam) arrays are manufactured. In the experiment, the hierarchical Ag-NP@Co3O4-NW/Ni-foam arrays exhibit strong SERS activity due to the higher density of the "hot spots" created from the large quantities of neighboring Ag NPs. Using this hierarchical 3D SERS substrates, the crystal violet (a banned drug of aquaculture) with concentration down to 10-14 mol/L can be detected, which shows potential application in SERS-based rapid trace-level detection of harmful food additives.

  19. Optimal power allocation to minimize SER for multinode amplify-and-forward cooperative communication systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An optimal power allocation (OPA) method with mean channel gains is proposed for a multinode amplify-and-forward cooperative communication system. By making use of M-PSK modulation, a closed-form symbol-error-rate (SER) formulation and corresponding upper bound are first derived. Subsequently the OPA method is utilized to minimize the SER. Comparison of the SER of the proposed OPA method with that of the equal power allocation (EPA) method, shows that the SER of both methods, which is approximately optimal performance, is almost the same when relays are near the source. OPA outperforms the EPA when the relays are near the middle between the source and destination or near the destination. The proposed OPA method depends only on the ratio of mean channel gains of the source-to-relay to those of the relay-to-destination. Extensive simulations are performed to validate the theoretical results.

  20. SERS and RAIR for Molecular Structure of Phenylazonaphthalene terminated Self-Assembled Monolayer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The SAMs of 10-[4-(4-phenylazo)naphth-l-oxyl]-l-decanethiol (Compound 1) on gold were prepared. Their molecular structures were determined by surface enhanced Raman spectroscopy (SERS) and reflection absorption infrared spectroscopy (RAIR).

  1. Water Ser - areng läbi torude ja üle kraavide / Ain Alvela

    Index Scriptorium Estoniae

    Alvela, Ain, 1967-

    2007-01-01

    1992. aastal asutatud vee- ja kanalisatsioonitorustike paigaldamisele spetsialiseerunud perefirma AS Water Ser on kasvanud rahvusvaheliselt mainekaks kontserniks. Vt. samas: Perefirma arengu kronoloogia; Amet sai alguse teismelise eas kraavikaevamisest. Kommenteerivad Andrus Piir ja Toomas Kapp

  2. Ser o estar "queer" en Latinoamerica? El devenir emancipador en: Lemebel, Perlongher y Arenas

    National Research Council Canada - National Science Library

    Arboleda Rios, Paola

    2011-01-01

    ... rebeldes para re-imaginar el proyecto queer latinoamericano. Sus creaciones contestan los modelos importados tanto de analisis teorico como de formas de ser disidente y reivindican la importancia social del amor...

  3. Identification of a novel human tRNA(Ser(CGA)) functional in murine leukemia virus replication

    DEFF Research Database (Denmark)

    Lund, Anders Henrik; Schmitz, A; Pedersen, F S

    2000-01-01

    (CGA)) was detected in cell lines of human, monkey and mouse origin. The UCG codon is the most rarely used codon in human genes. The cloned human tRNA(Ser(CGA)) gene encodes an 85 nucleotide, intron-less tRNA, contains a consensus split intragenic promoter and is located at region p21.3-22.2 on chromosome 6......We have identified a human tRNA(Ser) isoacceptor matching the UCG codon. The tRNA was discovered via its ability to act in reverse transcription of a murine leukemia virus vector containing a complementary tRNA primer binding site (Lund et al., Nucleic Acids Res., 28 (2000) 791-799). The tRNA(Ser....... The integrity and functionality of the cloned tRNA(Ser(CGA)) gene was verified by in vitro transcription analysis in HeLa nuclear extracts....

  4. SERS detection of pneumonia in breath of children with cystic fibrosis

    DEFF Research Database (Denmark)

    Lauridsen, Rikke Kragh; Molin, Søren

    colonisation, if it can be detected in the breath. It was investigated if a nanopillar substrate for surface-enhanced Raman spectroscopy (SERS), developed in the Nanoprobes group, could be optimised for gas phase detection of HCN. The project consisted of 3 steps, of which the first was to establish a chemical...... substrate, which was then measured, to see if HCN was detected when a new P. aeruginosa colonisation occurred; and data was correlated to culturing of sputum from the patient’s lungs. The SERS substrate was optimised, and setups were developed for HCN(g) detection, for SERS detection of HCN from bacterial...... volatiles, and for collection and SERS substrate exposure to human breath. Five ppm HCN was successfully detected in gas phase, and KCN was detected down to 10-6 M. HCN detection was demonstrated from cultures of P. aeruginosa wild types, starting from the end of exponential / beginning of stationary growth...

  5. Phosphorylation of rat aquaporin-4 at Ser(111) is not required for channel gating

    DEFF Research Database (Denmark)

    Assentoft, Mette; Kaptan, Shreyas; Fenton, Robert A

    2013-01-01

    of a phosphorylation of AQP4.Ser(111) recorded no phosphorylation-induced change in water permeability. A phospho-specific antibody, exclusively recognizing AQP4 when phosphorylated on Ser(111) , failed to detect phosphorylation in cell lysate of rat brain stimulated by conditions proposed to induce phosphorylation...... is therefore of therapeutic interest. Phosphorylation of some aquaporins has been proposed to regulate their water permeability via gating of the channel itself. Protein kinase (PK)-dependent phosphorylation of Ser(111) has been reported to increase the water permeability of AQP4 expressed in an astrocytic...... cell line. This possibility was, however, questioned based on the crystal structure of the human AQP4. Our study aimed to resolve if Ser(111) was indeed a site involved in phosphorylation-mediated gating of AQP4. The water permeability of AQP4-expressing Xenopus oocytes was not altered by a range...

  6. Water Ser - areng läbi torude ja üle kraavide / Ain Alvela

    Index Scriptorium Estoniae

    Alvela, Ain, 1967-

    2007-01-01

    1992. aastal asutatud vee- ja kanalisatsioonitorustike paigaldamisele spetsialiseerunud perefirma AS Water Ser on kasvanud rahvusvaheliselt mainekaks kontserniks. Vt. samas: Perefirma arengu kronoloogia; Amet sai alguse teismelise eas kraavikaevamisest. Kommenteerivad Andrus Piir ja Toomas Kapp

  7. Percolation threshold gold films on columnar coatings: characterisation for SERS applications

    CERN Document Server

    Balcytis, Armandas; Wang, Xuewen; Seniutinas, Gediminas; Drazdys, Ramutis; Stoddart, Paul R; Juodkazis, Saulius

    2016-01-01

    Percolation of gold films of ~15 nm thickness was controlled to achieve the largest openings during Au deposition. Gold was evaporated on 300-nm-thick films of nanostructured porous and columnar SiO2, TiO2 and MgF2 which were deposited by controlling the angle, rotation speed during film formation and ambient pressure. The gold films were tested for SERS performance using thiophenol reporter molecules which form a stable self-assembled monolayer on gold. The phase retardation of these SERS substrates was up to 5% for wavelengths in the visible spectral range, as measured by Stokes polarimetry. The SERS intensity on gold percolation films can reach 10^3 counts/(mW.s) for tight focusing in air, while back-side excitation through the substrate has shown the presence of an additional SERS enhancement via the Fresnel near-field mechanism.

  8. PGC-1alpha Gly482Ser polymorphism associates with hypertension among Danish whites

    DEFF Research Database (Denmark)

    Andersen, Gitte; Wegner, Lise; Jensen, Dorit Packert

    2005-01-01

    . The common Gly482Ser polymorphism of PGC-1alpha has previously shown association with arterial hypertension among Austrian men. Thus, we aimed at investigating this relationship in the Danish white population. The Gly482Ser polymorphism was genotyped in a total of 2562 Danish white subjects using polymerase...... chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and a GenoView locked nucleic acid assay (LNA), and the relationships of this variant with blood pressure levels and arterial hypertension were analyzed. Furthermore, we performed a combined analysis of the data from the present study...... in combination with previously published results. The Ser/Ser genotype was significantly associated with a reduced risk of hypertension and with lower systolic, diastolic, and mean arterial blood pressure levels, predominantly among women. Finally, in a combined analysis using data obtained in both sexes...

  9. DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity

    Science.gov (United States)

    Prinz, J.; Heck, C.; Ellerik, L.; Merk, V.; Bald, I.

    2016-03-01

    DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Electronic supplementary information (ESI) available: Additional information about materials and methods, designs of DNA origami templates, height profiles, additional SERS spectra, assignment of DNA

  10. O ser e o nada de Sartre: uma "descoberta" filosófica dos "tempos modernos"

    OpenAIRE

    Cristina Diniz Mendonça

    1994-01-01

    Este artigo indica que o Ensaio de ontologia fenomenológica de Sartre, O ser e o nada, poderia ser lido como uma recriação filosófica de uma experiência histórica crucial. This article defends the view that Sartre's phenomenological ontology essay, L'Être et le Néant, could be understood as a philosophical re-creation of a crucial historical experience.

  11. Determination of histamine in fish by Surface Enhanced Raman Spectroscopy using silver colloid SERS substrates.

    Science.gov (United States)

    Janči, Tibor; Valinger, Davor; Gajdoš Kljusurić, Jasenka; Mikac, Lara; Vidaček, Sanja; Ivanda, Mile

    2017-06-01

    This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content. Partial least square (PLS) regression models confirmed reliability of detection and spectral analysis of histamine with SERS. In histamine concentration range 0-200mgkg(-1), significant in legislative and fish quality control aspects, PLS regression model based on spectral range 1139.9-1643.7cm(-1) showed linear trend with R(2)pred=0.962, RPD=7.250. Presented protocol for histamine extraction and purification followed by SERS analysis coupled with chemometric approach, enabled development of rapid and inexpensive method for histamine determination in fish.

  12. SERS as an advanced tool for investigating chloroethyl nitrosourea derivatives complexation with DNA.

    Science.gov (United States)

    Agarwal, Shweta; Ray, Bhumika; Mehrotra, Ranjana

    2015-11-01

    We report surface-enhanced Raman spectroscopic (SERS) studies on free calf thymus DNA and its complexes with anti-tumor chloroethyl nitrosourea derivatives; semustine and nimustine. Since, first incident of SERS in 1974, it has rapidly established into an analytical tool, which can be used for the trace detection and characterization of analytes. Here, we depict yet another application of SERS in the field of drug-DNA interaction and thereby, its promising role in rational designing of new chemotherapeutic agents. Vibrational spectral analysis has been performed in an attempt to delineate the anti-cancer action mechanism of above mentioned nitrosourea derivatives. Strong SERS bands associated with the complexation of DNA with semustine and nimustine have been observed, which reveal binding of nitrosourea derivatives with heterocyclic nitrogenous base pair of DNA duplex. Formation of dG-dC interstrand cross-link in DNA double helices is also suggested by the SERS spectral outcomes of CENUs-DNA adduct. Results, demonstrated here, reflect recent progress in the newly developing field of drug-DNA interaction analysis via SERS.

  13. Inkjet-printed paper-based SERS dipsticks and swabs for trace chemical detection.

    Science.gov (United States)

    Yu, Wei W; White, Ian M

    2013-02-21

    We demonstrate a paper-based surface swab and lateral-flow dipstick that includes an inkjet-printed surface-enhanced Raman spectroscopy (SERS) substrate for analyte detection. Due to capillary-action wicking of cellulose, the paper dipstick enables extremely simple and pump-free loading of liquid samples into the detection device, and in addition provides inherent analyte concentration within the detection volume. Furthermore, the flexible nature of the paper-based SERS device also enables it to act as a swab to collect analyte molecules directly from a large-area surface; the collected analyte molecules can then be focused into a small-volume SERS-active region by lateral-flow concentration. These capabilities are unseen in today's SERS substrates and microfluidic SERS devices. Using these novel lateral-flow paper SERS devices, we achieved detection limits as low as 95 fg of Rhodamine 6G (R6G), 413 pg of the organophosphate malathion, 9 ng of heroin, and 15 ng of cocaine. Moreover, the measurements show that the technique is quantitative and is repeatable across multiple swabs and dipsticks. The results reported here may lead to ultra-low-cost portable applications in trace chemical detection.

  14. Designing multilayered nanoplatforms for SERS-based detection of genetically modified organisms

    Energy Technology Data Exchange (ETDEWEB)

    Uluok, Saadet [Dumlupinar University, Department of Chemistry, Faculty of Arts and Sciences (Turkey); Guven, Burcu [Hacettepe University, Department of Food Engineering, Faculty of Engineering (Turkey); Eksi, Haslet [Hacettepe University, Food Research Center (Turkey); Ustundag, Zafer [Dumlupinar University, Department of Chemistry, Faculty of Arts and Sciences (Turkey); Tamer, Ugur [Gazi University, Department of Analytical Chemistry, Faculty of Pharmacy (Turkey); Boyaci, Ismail Hakki, E-mail: ihb@hacettepe.edu.tr [Hacettepe University, Department of Food Engineering, Faculty of Engineering (Turkey)

    2015-01-15

    In this study, the multilayered surface-enhanced Raman spectroscopy (SERS) platforms were developed for the analysis of genetically modified organisms (GMOs). For this purpose, two molecules [11-mercaptoundecanoic acid (11-MUA) and 2-mercaptoethylamine (2-MEA)] were attached with Au{sub rod} and Au{sub spherical} nanoparticles to form multilayered constructions on the gold (Au){sub slide} surface. The best multilayered platform structure was chosen depending on SERS enhancement, and this surface was characterised with atomic force microscopy (AFM) and attenuated total reflectance Fourier transform infrared spectroscopy. After the optimum multilayered SERS platform and nanoparticle interaction was identified, the oligonucleotides on the Au{sub rod} nanoparticles and Au{sub slide} were combined to determine target concentrations from the 5,5′-dithiobis (2-nitrobenzoic acid) (DTNB) signals using SERS. The correlation between the SERS intensities for DTNB and target concentrations was found to be linear within a range of 10 pM to 1 µM, and with a detection limit of 34 fM. The selectivity and specificity of the developed sandwich assay were tested using negative and positive controls, and nonsense and real sample studies. The obtained results showed that the multilayered SERS sandwich method allows for sensitive, selective, and specific detection of oligonucleotide sequences.

  15. Fabrication of Gold-Coated Ultra-Thin Anodic Porous Alumina Substrates for Augmented SERS

    Directory of Open Access Journals (Sweden)

    Chiara Toccafondi

    2016-05-01

    Full Text Available Anodic porous alumina (APA is a nanostructured material used as a template in several nanotechnological applications. We propose the use of APA in ultra-thin form (<100 nm for augmented surface-enhanced Raman scattering (SERS. Here, the effect of in-depth thinning of the APA nanostructures for possible maximization of SERS was addressed. Anodization was carried out on ultra-thin films of aluminum on glass and/or silicon, followed by pore-opening. Gold (Au was overcoated and micro‑Raman/SERS measurements were carried out on test target analytes. Finite integration technique simulations of the APA-Au substrate were used both for the experimental design and simulations. It was observed that, under optimized conditions of APA and Au thickness, the SERS enhancement is higher than on standard APA-Au substrates based on thin (~100 nm APA by up to a factor of ~20 for test molecules of mercaptobenzoic acid. The agreement between model and experimental results confirms the current understanding of SERS as being mainly due to the physical origin of plasmon resonances. The reported results represent one step towards micro-technological, integrated, disposable, high-sensitivity SERS chemical sensors and biosensors based on similar substrates.

  16. Application of SERS spectroscopy for detection of trace components in urinary deposits

    Science.gov (United States)

    Pucetaite, Milda; Velicka, Martynas; Tamosaityte, Sandra; Sablinskas, Valdas

    2014-03-01

    Surface-enhanced Raman scattering (SERS) spectroscopy can be a useful tool in regard to disease diagnosis and prevention. Advantage of SERS over conventional Raman spectroscopy is its significantly increased signal (up to factor of 106-108) which allows detection of trace amounts of substances in the sample. So far, this technique is successfully used for analysis of food, pieces of art and various biochemical/biomedical samples. In this work, we survey the possibility of applying SERS spectroscopy for detection of trace components in urinary deposits. Early discovery together with the identification of the exact chemical composition of urinary sediments could be crucial for taking appropriate preventive measures that inhibit kidney stone formation or growth processes. In this initial study, SERS spectra (excitation wavelength - 1064 nm) of main components of urinary deposits (calcium oxalate, uric acid, cystine, etc.) were recorded by using silver (Ag) colloid. Spectra of 10-3-10-5 M solutions were obtained. While no/small Raman signal was detected without the Ag colloid, characteristic peaks of the substances could be clearly separated in the SERS spectra. This suggests that even small amounts of the components could be detected and taken into account while determining the type of kidney stone forming in the urinary system. We found for the first time that trace amounts of components constituting urinary deposits could be detected by SERS spectroscopy. In the future study, the analysis of centrifuged urine samples will be carried out.

  17. Biofabrication of chitosan-silver composite SERS substrates enabling quantification of adenine by a spectroscopic shift

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X L; Bentley, W E [Institute for Bioscience and Biotechnology Research (IBBR), University of Maryland, College Park, MD 20742 (United States); Buckhout-White, S; Rubloff, G W, E-mail: rubloff@umd.edu [Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742 (United States)

    2011-09-15

    Surface-enhanced Raman scattering (SERS) has grown dramatically as an analytical tool for the sensitive and selective detection of molecules adsorbed on nano-roughened noble metal structures. Quantification with SERS based on signal intensity remains challenging due to the complicated fabrication process to obtain well-dispersed nanoparticles and well-ordered substrates. We report a new biofabrication strategy of SERS substrates that enable quantification through a newly discovered spectroscopic shift resulting from the chitosan-analyte interactions in solution. We demonstrate this phenomenon by the quantification of adenine, which is an essential part of the nucleic acid structure and a key component in pathways which generate signal molecules for bacterial communications. The SERS substrates were fabricated simply by sequential electrodeposition of chitosan on patterned gold electrodes and electroplating of a silver nitrate solution through the chitosan scaffold to form a chitosan-silver nanoparticle composite. Active SERS signals of adenine solutions were obtained in real time from the chitosan-silver composite substrates with a significant concentration-dependent spectroscopic shift. The Lorentzian curve fitting of the dominant peaks suggests the presence of two separate peaks with a concentration-dependent area percentage of the separated peaks. The chitosan-mediated composite SERS substrates can be easily biofabricated on predefined electrodes within microfluidic channels for real-time detection in microsystems.

  18. Chitosan-coated anisotropic silver nanoparticles as a SERS substrate for single-molecule detection

    Science.gov (United States)

    Potara, Monica; Baia, Monica; Farcau, Cosmin; Astilean, Simion

    2012-02-01

    Surface-enhanced Raman spectroscopy (SERS) is a technique that has become widely used for identifying and providing structural information about molecular species in low concentration. There is an ongoing interest in finding optimum particle size, shape and spatial distribution for optimizing the SERS substrates and pushing the sensitivity toward the single-molecule detection limit. This work reports the design of a novel, biocompatible SERS substrate based on small clusters of anisotropic silver nanoparticles embedded in a film of chitosan biopolymer. The SERS efficiency of the biocompatible film is assessed by employing Raman imaging and spectroscopy of adenine, a significant biological molecule. By combining atomic force microscopy with SERS imaging we find that the chitosan matrix enables the formation of small clusters of silver nanoparticles, with junctions and gaps that greatly enhance the Raman intensities of the adsorbed molecules. The study demonstrates that chitosan-coated anisotropic silver nanoparticle clusters are sensitive enough to be implemented as effective plasmonic substrates for SERS detection of nonresonant analytes at the single-molecule level.

  19. Surface enhanced Raman spectroscopy (SERS) for in vitro diagnostic testing at the point of care

    Science.gov (United States)

    Marks, Haley; Schechinger, Monika; Garza, Javier; Locke, Andrea; Coté, Gerard

    2017-06-01

    Point-of-care (POC) device development is a growing field that aims to develop low-cost, rapid, sensitive in-vitro diagnostic testing platforms that are portable, self-contained, and can be used anywhere - from modern clinics to remote and low resource areas. In this review, surface enhanced Raman spectroscopy (SERS) is discussed as a solution to facilitating the translation of bioanalytical sensing to the POC. The potential for SERS to meet the widely accepted "ASSURED" (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable) criterion provided by the World Health Organization is discussed based on recent advances in SERS in vitro assay development. As SERS provides attractive characteristics for multiplexed sensing at low concentration limits with a high degree of specificity, it holds great promise for enhancing current efforts in rapid diagnostic testing. In outlining the progression of SERS techniques over the past years combined with recent developments in smart nanomaterials, high-throughput microfluidics, and low-cost paper diagnostics, an extensive number of new possibilities show potential for translating SERS biosensors to the POC.

  20. Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate

    Directory of Open Access Journals (Sweden)

    Shavini Wijesuriya

    2016-10-01

    Full Text Available Surface-enhanced Raman spectroscopy (SERS substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH4OH and nitric acid (HNO3 helped obtain roughened Ag SERS substrates. Scanning electron microscopy (SEM and interferometry were used to visualize and quantify surface roughness. Flattened Ag wires had inherent, but non-uniform roughness having peaks and valleys in the microscale. NH4OH treatment removed dirt and smoothened the surface, while HNO3 treatment produced a flake-like morphology with visibly more surface roughness features on Ag metal. SERS efficacy was tested using 4-methylbenzenethiol (MBT. The best SERS enhancement for 1 mM MBT was observed for Ag metal etched for 30 s in NH4OH followed by 10 s in HNO3. Further, MBT could be quantified with detection limits of 1 pM and 100 µM, respectively, using 514 nm and 1064 nm Raman spectrometers. Thus, a rapid and less energy intensive method for producing solid Ag SERS substrate and its efficacy in analyte sensing was demonstrated.

  1. SERS based immuno-microwell arrays for multiplexed detection of foodborne pathogenic bacteria

    Science.gov (United States)

    Sun, Jian; Hankus, Mikella E.; Cullum, Brian M.

    2009-05-01

    A novel surface enhanced Raman scattering (SERS)-based immuno-microwell array has been developed for multiplexed detection of foodborne pathogenic bacteria. The immuno-microwell array was prepared by immobilizing the optical addressable immunomagnetic beads (IMB) into the microwell array on one end of a fiber optic bundle. The IMBs, magnetic beads coated with specific antibody to specific bacteria, were used for immunomagnetic separation (IMS) of corresponding bacteria. The magnetic separation by the homemade magnetic separation system was evaluated in terms of the influences of several important parameters including the beads concentration, the sample volume and the separation time. IMS separation efficiency of the model bacteria E.coli O157:H7 was 63% in 3 minutes. The microwell array was fabricated on hydrofluoric acid etched end of a fiber optic bundle containing 30,000 fiber elements. After being coated with silver, the microwell array was used as a uniform SERS substrate with the relative standard deviation of the SERS enhancement across the microwell array < 2% and the enhancement factor as high as 2.18 x 107. The antibody modified microwell array was prepared for bacteria immobilization into the microwell array, which was characterized by a sandwich immunoassay. To demonstrate the potential of multiplexed SERS detection with the immuno-microwell array, the SERS spectra of different Raman dye labeled magnetic beads as well as mixtures were measured on the mircrowell array. In bead mixture, different beads were identified by the characteristic SERS bands of the corresponding Raman label.

  2. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

  3. Surface enhanced Raman spectroscopy (SERS for in vitro diagnostic testing at the point of care

    Directory of Open Access Journals (Sweden)

    Marks Haley

    2017-06-01

    Full Text Available Point-of-care (POC device development is a growing field that aims to develop low-cost, rapid, sensitive in-vitro diagnostic testing platforms that are portable, self-contained, and can be used anywhere – from modern clinics to remote and low resource areas. In this review, surface enhanced Raman spectroscopy (SERS is discussed as a solution to facilitating the translation of bioanalytical sensing to the POC. The potential for SERS to meet the widely accepted “ASSURED” (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable criterion provided by the World Health Organization is discussed based on recent advances in SERS in vitro assay development. As SERS provides attractive characteristics for multiplexed sensing at low concentration limits with a high degree of specificity, it holds great promise for enhancing current efforts in rapid diagnostic testing. In outlining the progression of SERS techniques over the past years combined with recent developments in smart nanomaterials, high-throughput microfluidics, and low-cost paper diagnostics, an extensive number of new possibilities show potential for translating SERS biosensors to the POC.

  4. Reproducible E. coli detection based on label-free SERS and mapping.

    Science.gov (United States)

    Yang, Danting; Zhou, Haibo; Haisch, Christoph; Niessner, Reinhard; Ying, Yibin

    2016-01-01

    The biosensing for rapid detection of bacteria based on surface-enhanced Raman scattering (SERS) has been widely explored for recent years. It is still a challenge to achieve a high sensitive, reproducible label free detection method for bacteria. In this work, a label-free SERS detection method of Escherichia coli based on incubation with silver colloid was reported. Optimized incubation conditions including shaking speed, time and temperature were used to help construct a rapid SERS method for E. coli analysis. It was found that the enhancement of the Raman signal of E. coli could be achieved to 1.8×10(4) cps (counts per second) with high reproducibility. Three strains of E. coli DSM 1116/498/5695 could be successfully discriminated using such SERS method combining discriminant analysis. Finally, the lowest concentration of E. coli at 1×10(5) cell/mL can be detected by SERS mapping. Thus, our detection method offers higher sensitivity and reproducibility compared to previously reported label free simple-mixing methods, opening an avenue for developing various SERS-based biosensor.

  5. Sensitive DNA detection and SNP discrimination using ultrabright SERS nanorattles and magnetic beads for malaria diagnostics.

    Science.gov (United States)

    Ngo, Hoan T; Gandra, Naveen; Fales, Andrew M; Taylor, Steve M; Vo-Dinh, Tuan

    2016-07-15

    One of the major obstacles to implement nucleic acid-based molecular diagnostics at the point-of-care (POC) and in resource-limited settings is the lack of sensitive and practical DNA detection methods that can be seamlessly integrated into portable platforms. Herein we present a sensitive yet simple DNA detection method using a surface-enhanced Raman scattering (SERS) nanoplatform: the ultrabright SERS nanorattle. The method, referred to as the nanorattle-based method, involves sandwich hybridization of magnetic beads that are loaded with capture probes, target sequences, and ultrabright SERS nanorattles that are loaded with reporter probes. Upon hybridization, a magnet was applied to concentrate the hybridization sandwiches at a detection spot for SERS measurements. The ultrabright SERS nanorattles, composed of a core and a shell with resonance Raman reporters loaded in the gap space between the core and the shell, serve as SERS tags for signal detection. Using this method, a specific DNA sequence of the malaria parasite Plasmodium falciparum could be detected with a detection limit of approximately 100 attomoles. Single nucleotide polymorphism (SNP) discrimination of wild type malaria DNA and mutant malaria DNA, which confers resistance to artemisinin drugs, was also demonstrated. These test models demonstrate the molecular diagnostic potential of the nanorattle-based method to both detect and genotype infectious pathogens. Furthermore, the method's simplicity makes it a suitable candidate for integration into portable platforms for POC and in resource-limited settings applications.

  6. Improving SERS activity of inositol hexaphosphate capped silver nanoparticles: Fe3+ as a switcher.

    Science.gov (United States)

    Guo, Xiaoyu; Fu, Yichen; Fu, Shuyue; Wang, Hui; Yang, Tianxi; Wen, Ying; Yang, Haifeng

    2014-07-21

    Inositol hexaphosphate (IP6) capped silver nanoparticles (IP6@AgNPs) were fabricated as surface-enhanced Raman scattering (SERS) active substrates. SERS activity of IP6@AgNPs could be further improved via adding due amounts of Fe(3+) to form Fe(3+)-IP6@AgNPs. The mechanism of Fe(3+)-induced SERS improvement of IP6@AgNPs can be attributed to the strong interaction of IP6 and Fe(3+), which leads to controllable adjustment of the gap among neighboring nanoparticles to produce "hot spots". The above mechanism was confirmed with ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Such Fe(3+)-IP6@AgNPs-based SERS system was used to detect Rhodamine 6G (R6G) down to the trace level of 10(-10) mol L(-1). Besides, New Fuchsin (NF) was also used as a Raman probe to calculate the enhancement factor (EF) of IP6@AgNPs without and with Fe(3+). The SERS activity of IP6@AgNPs happened extreme decrease after one-year storage and could be recovered to great extent aided by the addition of Fe(3+). The Fe(3+) optimized IP6@AgNPs system could be applied to detect thymine at trace level by SERS.

  7. Phosphorylation of hepatitis C virus RNA polymerases ser29 and ser42 by protein kinase C-related kinase 2 regulates viral RNA replication.

    Science.gov (United States)

    Han, Song-Hee; Kim, Seong-Jun; Kim, Eun-Jung; Kim, Tae-Eun; Moon, Jae-Su; Kim, Geon-Woo; Lee, Seung-Hoon; Cho, Kun; Yoo, Jong Shin; Son, Woo Sung; Rhee, Jin-Kyu; Han, Seung Hyun; Oh, Jong-Won

    2014-10-01

    Hepatitis C virus (HCV) nonstructural protein 5B (NS5B), an RNA-dependent RNA polymerase (RdRp), is the key enzyme for HCV RNA replication. We previously showed that HCV RdRp is phosphorylated by protein kinase C-related kinase 2 (PRK2). In the present study, we used biochemical and reverse-genetics approaches to demonstrate that HCV NS5B phosphorylation is crucial for viral RNA replication in cell culture. Two-dimensional phosphoamino acid analysis revealed that PRK2 phosphorylates NS5B exclusively at its serine residues in vitro and in vivo. Using in vitro kinase assays and mass spectrometry, we identified two phosphorylation sites, Ser29 and Ser42, in the Δ1 finger loop region that interacts with the thumb subdomain of NS5B. Colony-forming assays using drug-selectable HCV subgenomic RNA replicons revealed that preventing phosphorylation by Ala substitution at either Ser29 or Ser42 impairs HCV RNA replication. Furthermore, reverse-genetics studies using HCV infectious clones encoding phosphorylation-defective NS5B confirmed the crucial role of these PRK2 phosphorylation sites in viral RNA replication. Molecular-modeling studies predicted that the phosphorylation of NS5B stabilizes the interactions between its Δ1 loop and thumb subdomain, which are required for the formation of the closed conformation of NS5B known to be important for de novo RNA synthesis. Collectively, our results provide evidence that HCV NS5B phosphorylation has a positive regulatory role in HCV RNA replication. While the role of RNA-dependent RNA polymerases (RdRps) in viral RNA replication is clear, little is known about their functional regulation by phosphorylation. In this study, we addressed several important questions about the function and structure of phosphorylated hepatitis C virus (HCV) nonstructural protein 5B (NS5B). Reverse-genetics studies with HCV replicons encoding phosphorylation-defective NS5B mutants and analysis of their RdRp activities revealed previously unidentified

  8. Signal enhancement ratio (SER) quantified from breast DCE-MRI and breast cancer risk

    Science.gov (United States)

    Wu, Shandong; Kurland, Brenda F.; Berg, Wendie A.; Zuley, Margarita L.; Jankowitz, Rachel C.; Sumkin, Jules; Gur, David

    2015-03-01

    Breast magnetic resonance imaging (MRI) is recommended as an adjunct to mammography for women who are considered at elevated risk of developing breast cancer. As a key component of breast MRI, dynamic contrast-enhanced MRI (DCE-MRI) uses a contrast agent to provide high intensity contrast between breast tissues, making it sensitive to tissue composition and vascularity. Breast DCE-MRI characterizes certain physiologic properties of breast tissue that are potentially related to breast cancer risk. Studies have shown that increased background parenchymal enhancement (BPE), which is the contrast enhancement occurring in normal cancer-unaffected breast tissues in post-contrast sequences, predicts increased breast cancer risk. Signal enhancement ratio (SER) computed from pre-contrast and post-contrast sequences in DCE-MRI measures change in signal intensity due to contrast uptake over time and is a measure of contrast enhancement kinetics. SER quantified in breast tumor has been shown potential as a biomarker for characterizing tumor response to treatments. In this work we investigated the relationship between quantitative measures of SER and breast cancer risk. A pilot retrospective case-control study was performed using a cohort of 102 women, consisting of 51 women who had diagnosed with unilateral breast cancer and 51 matched controls (by age and MRI date) with a unilateral biopsy-proven benign lesion. SER was quantified using fully-automated computerized algorithms and three SER-derived quantitative volume measures were compared between the cancer cases and controls using logistic regression analysis. Our preliminary results showed that SER is associated with breast cancer risk, after adjustment for the Breast Imaging Reporting and Data System (BI-RADS)-based mammographic breast density measures. This pilot study indicated that SER has potential for use as a risk factor for breast cancer risk assessment in women at elevated risk of developing breast cancer.

  9. Rapid Detection of Listeria by Bacteriophage Amplification and SERS-Lateral Flow Immunochromatography.

    Science.gov (United States)

    Stambach, Nicholas R; Carr, Stephanie A; Cox, Christopher R; Voorhees, Kent J

    2015-12-14

    A rapid Listeria detection method was developed utilizing A511 bacteriophage amplification combined with surface-enhanced Raman spectroscopy (SERS) and lateral flow immunochromatography (LFI). Anti-A511 antibodies were covalently linked to SERS nanoparticles and printed onto nitrocellulose membranes. Antibody-conjugated SERS nanoparticles were used as quantifiable reporters. In the presence of A511, phage-SERS nanoparticle complexes were arrested and concentrated as a visible test line, which was interrogated quantitatively by Raman spectroscopy. An increase in SERS intensity correlated to an increase in captured phage-reporter complexes. SERS limit of detection was 6 × 10(6) pfu·mL(-1), offering detection below that obtainable by the naked eye (LOD 6 × 10(7) pfu·mL(-1)). Phage amplification experiments were carried out at a multiplicity of infection (MOI) of 0.1 with 4 different starting phage concentrations monitored over time using SERS-LFI and validated by spot titer assay. Detection of L. monocytogenes concentrations of 1 × 10(7) colony forming units (cfu)·mL(-1), 5 × 10(6) cfu·mL(-1), 5 × 10(5) cfu·mL(-1) and 5 × 10(4) cfu·mL(-1) was achieved in 2, 2, 6, and 8 h, respectively. Similar experiments were conducted at a constant starting phage concentration (5 × 10(5) pfu·mL(-1)) with MOIs of 1, 2.5, and 5 and were detected in 2, 4, and 5 h, respectively.

  10. Rapid Detection of Listeria by Bacteriophage Amplification and SERS-Lateral Flow Immunochromatography

    Directory of Open Access Journals (Sweden)

    Nicholas R. Stambach

    2015-12-01

    Full Text Available A rapid Listeria detection method was developed utilizing A511 bacteriophage amplification combined with surface-enhanced Raman spectroscopy (SERS and lateral flow immunochromatography (LFI. Anti-A511 antibodies were covalently linked to SERS nanoparticles and printed onto nitrocellulose membranes. Antibody-conjugated SERS nanoparticles were used as quantifiable reporters. In the presence of A511, phage-SERS nanoparticle complexes were arrested and concentrated as a visible test line, which was interrogated quantitatively by Raman spectroscopy. An increase in SERS intensity correlated to an increase in captured phage-reporter complexes. SERS limit of detection was 6 × 106 pfu·mL−1, offering detection below that obtainable by the naked eye (LOD 6 × 107 pfu·mL−1. Phage amplification experiments were carried out at a multiplicity of infection (MOI of 0.1 with 4 different starting phage concentrations monitored over time using SERS-LFI and validated by spot titer assay. Detection of L. monocytogenes concentrations of 1 × 107 colony forming units (cfu·mL−1, 5 × 106 cfu·mL−1, 5 × 105 cfu·mL−1 and 5 × 104 cfu·mL−1 was achieved in 2, 2, 6, and 8 h, respectively. Similar experiments were conducted at a constant starting phage concentration (5 × 105 pfu·mL−1 with MOIs of 1, 2.5, and 5 and were detected in 2, 4, and 5 h, respectively.

  11. Sensitive multiplex detection of serological liver cancer biomarkers using SERS-active photonic crystal fiber probe.

    Science.gov (United States)

    Dinish, U S; Balasundaram, Ghayathri; Chang, Young Tae; Olivo, Malini

    2014-11-01

    Surface-enhanced Raman scattering (SERS) spectroscopy possesses the most promising advantage of multiplex detection for biosensing applications, which is achieved due to the narrow 'fingerprint' Raman spectra from the analyte molecules. We developed an ultrasensitive platform for the multiplex detection of cancer biomarkers by combining the SERS technique with a hollow-core photonic crystal fiber (HCPCF). Axially aligned air channels inside the HCPCF provide an excellent platform for optical sensing using SERS. In addition to the flexibility of optical fibers, HCPCF provides better light confinement and a larger interaction length for the guided light and the analyte, resulting in an improvement in sensitivity to detect low concentrations of bioanalytes in extremely low sample volumes. Herein, for the first time, we demonstrate the sensitive multiplex detection of biomarkers immobilized inside the HCPCF using antibody-conjugated SERS-active nanoparticles (SERS nanotags). As a proof-of-concept for targeted multiplex detection, initially we carried out the sensing of epidermal growth factor receptor (EGFR) biomarker in oral squamous carcinoma cell lysate using three different SERS nanotags. Subsequently, we also achieved simultaneous detection of hepatocellular carcinoma (HCC) biomarkers-alpha fetoprotein (AFP) and alpha-1-antitrypsin (A1AT) secreted in the supernatant from Hep3b cancer cell line. Using a SERS-HCPCF sensing platform, we could successfully demonstrate the multiplex detection in an extremely low sample volume of ∼20 nL. In future, this study may lead to sensitive biosensing platform for the low concentration detection of biomarkers in an extremely low sample volume of body fluids to achieve early diagnosis of multiple diseases. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

  12. SERS study of transformation of phenylalanine to tyrosine under particle irradiation

    Science.gov (United States)

    Zhang, Jingjing; Huang, Qing; Yao, Guohua; Ke, Zhigang; Zhang, Hong; Lu, Yilin

    2014-08-01

    Surface enhanced Raman scattering or spectroscopy (SERS) is a very powerful analytical tool which has been widely applied in many scientific research and application fields. It is therefore also very intriguing for us to introduce SERS technique in the radiobiological research, where in many cases only a very few of biomolecules are subjected to changes which however can lead to significant biological effects. The radiation induced biochemical reactions are normally very sophisticated with different substances produced in the system, so currently it is still a big challenge for SERS to analyze such a mixture system which contains multiple analytes. In this context, this work aimed to establish and consolidate the feasibility of SERS as an effective tool in radiation chemistry, and this purpose, we employed SERS as a sensitive probe to a known process, namely, the oxidation of phenylalanine (Phe) under particle irradiation, where the energetic particles were obtained from either plasma discharge or electron-beam. During the irradiation, three types of tyrosine (Tyr), namely, p-Tyr, m-Tyr and o-Tyr were produced, and all these tyrosine isomers together with Phe could be identified and measured based on the SERS spectral analysis of the corresponding enhanced characteristic signals, namely, 1002 cm-1 for Phe, 1161 cm-1 for p-Tyr, 990 cm-1 for m-Tyr, and 970 cm-1 for o-Tyr, respectively. The estimation of the quantities of different tyrosine isomers were also given and verified by conventional method such as high performance liquid chromatography (HPLC). As for comparison of different ways of particle irradiation, our results also indicated that electron-beam irradiation was more efficient for converting Phe into Tyr than plasma discharge treatment, confirming the role of hydroxyl radicals in the Phe-Tyr conformation. Therefore, our work has not only demonstrated that SERS can be successfully applied in the radiobiological study, but also given insights into the

  13. Two new hemoglobin variants: Hb Brem-sur-Mer [beta9(A6)Ser-->Tyr] and Hb Passy [alpha81(F2)Ser-->Pro (alpha2)].

    Science.gov (United States)

    Lacan, Philippe; Moreau, Mathieu; Becchi, Michel; Zanella-Cleon, Isabelle; Aubry, Martine; Louis, Jean-Jacques; Couprie, Nicole; Francina, Alain

    2005-01-01

    Two new hemoglobin (Hb) variants: Hb Brem-sur-Mer [codon 9 (TCT-->TAT); beta9(A6)Ser-->Tyr] on the first exon of the beta-globin gene and Hb Passy [codon 81 (TCC-->CCC); alpha81(F2)Ser-->Pro (alpha2)] on the second exon of the alpha2-globin gene, are described. The two variants were characterized by DNA sequencing and mass spectrometry (MS). Hematological abnormalities: microcytosis and hypochromia were found only in the carrier of Hb Passy. In the absence of an association with an alpha-thalassemic deletion or mutation, the mutation 81(F2)Pro could induce a possible alpha-thalassemia (thal).

  14. Analysis on superhydrophobic silver decorated copper Oxide nanostructured thin films for SERS studies.

    Science.gov (United States)

    Jayram, Naidu Dhanpal; Aishwarya, D; Sonia, S; Mangalaraj, D; Kumar, P Suresh; Rao, G Mohan

    2016-09-01

    The present work demonstrates the superhydrophobic and Surface Enhanced Raman Spectroscopy (SERS) active substrate performance of silver coated copper oxide (Ag@CuO) nanostructured thin films prepared by the SILAR process. Super hydrophobic substrates that combine super hydrophobic condensation effect and high enhancement ability of Ag@CuO nanoflowers are investigated for SERS studies. The possible growth mechanism for the formation of nanoflower arrays from nanospindles has been discussed. Morphology and crystallinity of the Ag@CuO thin films are confirmed using FESEM and XRD. The results obtained in the present study indicate that the as-deposited hydrophobic nanospindles structure converts to super hydrophobic nanoflower arrays on annealing at 200°C. The Ag@CuO super hydrophobic nanoflowers thin film based SERS substrates show highly enhanced Raman spectra with an EF value of 2.0×10(7) for (Rhodamine 6G) R6G, allowing a detection limit from a 10(-10)molL(-1) solution. The present study may provide a new perception in fabricating efficient super hydrophobic substrates for SERS, suggesting that the fabricated substrates are promising candidates for trace analysis of R6G dye and are expected to be widely used as highly sensitive SERS active substrates for various toxic dyes in the future.

  15. Experimental and density functional theory study of Raman and SERS spectra of 5-amino-2-mercaptobenzimidazole.

    Science.gov (United States)

    Chen, Yufeng; Yang, Jin; Li, Zonglong; Li, Ran; Ruan, Weidong; Zhuang, Zhiping; Zhao, Bing

    2016-01-15

    Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) simulations were employed to study 5-amino-2-mercaptobenzimidazole (5-A-2MBI) molecules. Ag colloids were used as SERS substrates which were prepared by using hydroxylamine hydrochloride as reducing agent. Raman vibration modes and SERS characteristic peaks of 5-A-2MBI were assigned with the aid of DFT calculations. The molecular electrostatic potential (MEP) of 5-A-2MBI was used to discuss the possible adsorption behavior of 5-A-2MBI on Ag colloids. The spectral analysis showed that 5-A-2MBI molecules were slightly titled via the sulfur atoms adhering to the surfaces of Ag substrates. The obtained SERS spectral intensity decreased when lowering the 5-A-2MBI concentrations. A final detection limit on the concentration of 5×10(-7) mol · L(-1) was gained. SERS proved to be a simple, fast and reliable method for the detection and characterization of 5-A-2MBI molecules.

  16. Modos de ser enfermeiro-professor-no-ensino-do-cuidadode-enfermagem: um olhar heideggeriano

    Directory of Open Access Journals (Sweden)

    Luciara Fabiane Sebold

    2013-08-01

    Full Text Available Estudo qualitativo de abordagem fenomenológica. Objetivou desvelar, à luz do pensamento de Martin Heidegger, os modos de ser dos enfermeiros-professores na vivência de ensinar-aprender o cuidado de enfermagem em uma instituição federal de ensino superior do sul do Brasil. A técnica utilizada para captar os significados foi a entrevista fenomenológica com 11 docentes. A análise permitiu compreender os Modos de Ser enfermeiro-professor, que foram didaticamente apresentados em duas unidades de significado: Modo de ser enfermeiro para o cuidado; Modo de ser professor para o ensino do cuidado. Alguns professores identificam-se como enfermeiros, suas experiências profissionais são suas bases e a coexistência com outros pôde lhes servir de exemplo. Outros se percebem professores de enfermagem e desejam ensinar os desafios de ser enfermeiro, e aprimoram o cuidado através de pesquisas. Ao ensinar, envolvem-se com o universo de ensino no qual o cuidar também é aprender e ensinar.

  17. Effect of the size of silver nanoparticles on SERS signal enhancement

    Science.gov (United States)

    He, Rui Xiu; Liang, Robert; Peng, Peng; Norman Zhou, Y.

    2017-08-01

    The localized surface plasmon resonance arising from plasmonic materials is beneficial in solution-based and thin-film sensing applications, which increase the sensitivity of the analyte being tested. Silver nanoparticles from 35 to 65 nm in diameter were synthesized using a low-temperature method and deposited in a monolayer on a (3-aminopropyl)triethoxysilane (APTES)-functionalized glass slide. The effect of particle size on monolayer structure, optical behavior, and surface-enhanced Raman scattering (SERS) is studied. While increasing particle size decreases particle coverage, it also changes the localized surface plasmon resonance and thus the SERS activity of individual nanoparticles. Using a laser excitation wavelength of 633 nm, the stronger localized surface plasmon resonance coupling to this excitation wavelength at larger particle sizes trumps the loss in surface coverage, and greater SERS signals are observed. The SERS signal enhancement accounts for the higher SERS signal, which was verified using a finite element model of a silver nanoparticle dimer with various nanoparticle sizes and separation distances.

  18. Stilbazolium Merocyanine Dye Determination in Different Solutions, Concentrations and Colloids Using SERS

    DEFF Research Database (Denmark)

    Pajchrowski, Grzegorz; Abdali, Salim; Nørbygaard, Thomas

    2006-01-01

    Surface Enhanced Raman Scattering (SERS) measurements were carried out on stilbazolium merocyanine dye in methanol and pyridine solvents. Both solutions were measured in series of concentrations, covering a range of 5·10-5 M to 5·10-8 M. In these measurements Ag and Au colloids were used and the ......Surface Enhanced Raman Scattering (SERS) measurements were carried out on stilbazolium merocyanine dye in methanol and pyridine solvents. Both solutions were measured in series of concentrations, covering a range of 5·10-5 M to 5·10-8 M. In these measurements Ag and Au colloids were used...... and the results have shown that Ag colloids yield better enhancement in the Raman spectra of this dye. Moreover, the effect of adding NaCl solution to the SERS samples was also studied. All measurements were carried out using the state-of-the-art ChiralRaman instrument, which utilizes a 532 nm laser source. We...... report here on the success of using SERS to obtain Raman spectra of merocyanine dye at very low concentration in an attempt of new approach, which can be used for further investigations of the dye. The SERS spectra will here be reported and the results from different solutions, colloids, concentrations...

  19. Plasmonic hierarchical nanostructures with cascaded field enhancement and their SERS applications

    Science.gov (United States)

    Bai, Benfeng; Zhu, Zhendong

    2016-04-01

    Plasmonic nanostructures with strong near field "hot spots" are highly demanded in many applications such as surface enhanced Raman spectroscopy (SERS). Here, we present some specially designed plasmonic hierarchical nanostructures that combine geometric features of micro- and nanoscales. Owing to the mode coupling and hybridization in these multiscale systems that can produce the cascaded field enhancement (CFE) effect, extremely strong and highly confined field hot spots can be readily generated in nanoscale volumes. Two typical hierarchical nanostructures are presented: an Mshaped grating with 30 nm narrow V-shaped grooves and a nanoparticle-in-cavity (PIC) plasmonic nanoantenna array. A cost-effective, efficient and reliable fabrication technique based on room-temperature nanoimprinting and anisotropic reactive ion etching is developed to fabricate these plasmonic hierarchical nanostructures in large area, during which the nano-features can be finely controlled and tuned. The field distributions and enhancement in the proposed structures are experimentally characterized, which agree very well with the numerical simulations. SERS experiments show the SERS enhancement factor as high as 5×108 by employing these hierarchical nanostructures as SERS substrates, which verify the strong light-matter interaction and show the great potential of these devices as low-cost and highly-active substrates for SERS applications.

  20. Ag-SiO2 Janus particles based highly active SERS macroscopic substrates

    Science.gov (United States)

    Panwar, Kamlesh; Jassal, Manjeet; Agrawal, Ashwini K.

    2017-07-01

    Macroscopic SERS (M-SERS) substrate with high activity was fabricated by attaching Ag-SiO2 Janus particles with ∼3 nm sized silver nanoparticles (AgNPs) on a cellulosic film. The synthesized Ag-SiO2 Janus particles had in-situ deposited AgNPs on one-half and amine functionalization on the other-half, which was utilized for their fixation as a monolayer on cellulosic substrate. Raman spectrum of Rhodamine B (RhB) showed an enhancement factor of ∼5 × 104 for dye tagged on both Janus particles and M-SERS. In comparison, AgNPs with almost the same diameter, even after aggregation, did not show enhancement of Raman signals. The enhancement is attributed to in-situ reduction of silver precursor on the SiO2 surface leading to deposition of AgNPs and generation of a large number of fixed hot-spots in a controlled manner. The Janus particles and M-SERS with ∼3 nm sized AgNPs can find application as both SERS active as well as catalytic material.

  1. Application of silver nanodendrites deposited on silicon in SERS technique for the trace analysis of paraquat

    Science.gov (United States)

    Cao Dao, Tran; Quynh Ngan Luong, Truc; Cao, Tuan Anh; Kieu, Ngoc Minh; Le, Van Vu

    2016-03-01

    In order to detect trace concentrations of organic or biological molecules by surface-enhanced Raman scattering (SERS) technique, the SERS-active substrates with high enhancement factor are required. The silver nanodendrites (AgNDs) are a growing class of such SERS-active substrates. This report presents the preliminary results of the trace detection of paraquat (PQ), a commonly used herbicide, with the use of SERS-active substrates, which have been made from AgNDs deposited on silicon. The AgNDs were produced either by electroless deposition, or by electrodeposition onto a silicon wafer, using aqueous solution of HF and AgNO3. It was observed that the silver dendrites are formed only when AgNO3 concentration is high enough. Next, it was found that with the additional assistance of an electric potential in the electrodeposition, the dendrites have grown up with the more perfect ramification. The AgNDs with more perfect branching gave the Raman spectrum of PQ with higher enhancement factor. More specifically, while the SERS-active substrates prepared from electrodeposited AgNDs were able to detect PQ with concentration as low as 0.01 ppm, the ones made from electroless deposited AgNDs could only detect PQ at concentration of hundreds times higher.

  2. A naturally occurring diatom frustule as a SERS substrate for the detection and quantification of chemicals

    Science.gov (United States)

    Chamuah, Nabadweep; Chetia, Lakhi; Zahan, Nashrat; Dutta, Sibasish; Ahmed, Gazi A.; Nath, Pabitra

    2017-05-01

    Naturally occurring photonic crystal structures play an important role in different fields of application. Herein, we exploit the periodic pore pattern of a diatom frustule and demonstrate surface-enhanced Raman scattering (SERS) using its structure as a template for the SERS substrate. Gold nanoparticles (AuNPs) were initially allowed to self-assemble on the surface and inside the pores of the diatoms. The enhancement in the localized surface plasmon resonance (LSPR) field magnitude for the assembled AuNPs on the diatom frustule were studied using simulation software. For the proposed SERS substrate, an average field enhancement of the order of 108 magnitude was observed. We demonstrate the operation of the designed substrate for the detection and quantification of Raman signals from two Raman active samples, namely malachite green (MG) and fluoride concentrations in drinking water. Using the proposed SERS substrate, an MG concentration as low as 1 nM with a relative standard deviation (RSD) of 7.57% and a fluoride concentration of 100 nM with an RSD of 17.26% could be measured with the Raman spectrometer. We envision that the proposed technique could emerge as an inexpensive alternative fabrication method of SERS substrates which can produce an enhanced LSPR field magnitude and scatter intense Raman signals from Raman active samples.

  3. Water security: continuous monitoring of water distribution systems for chemical agents by SERS

    Science.gov (United States)

    Inscore, Frank; Shende, Chetan; Sengupta, Atanu; Farquharson, Stuart

    2007-04-01

    Ensuring safe water supplies requires continuous monitoring for potential poisons and portable analyzers to map distribution in the event of an attack. In the case of chemical warfare agents (CWAs) analyzers are needed that have sufficient sensitivity (part-per-billion), selectivity (differentiate the CWA from its hydrolysis products), and speed (less than 10 minutes) to be of value. We have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to meet these requirements by detecting CWAs and their hydrolysis products in water. The expected success of SERS is based on reported detection of single molecules, the one-to-one relationship between a chemical and its Raman spectrum, and the minimal sample preparation requirements. Recently, we have developed a simple sampling device designed to optimize the interaction of the target molecules with the SERS-active material with the goal of increasing sensitivity and decreasing sampling times. This sampling device employs a syringe to draw the water sample containing the analyte into a capillary filled with the SERS-active material. Recently we used such SERS-active capillaries to measure 1 ppb cyanide in water. Here we extend these measurements to nerve agent hydrolysis products using a portable Raman analyzer.

  4. Effect of toxicity of Ag nanoparticles on SERS spectral variance of bacteria.

    Science.gov (United States)

    Cui, Li; Chen, Shaode; Zhang, Kaisong

    2015-02-25

    Ag nanoparticles (NPs) have been extensively utilized in surface-enhanced Raman scattering (SERS) spectroscopy for bacterial identification. However, Ag NPs are toxic to bacteria. Whether such toxicity can affect SERS features of bacteria and interfere with bacterial identification is still unknown and needed to explore. Here, by carrying out a comparative study on non-toxic Au NPs with that on toxic Ag NPs, we investigated the influence of nanoparticle concentration and incubation time on bacterial SERS spectral variance, both of which were demonstrated to be closely related to the toxicity of Ag NPs. Sensitive spectral alterations were observed on Ag NPs with increase of NPs concentration or incubation time, accompanied with an obvious decrease in number of viable bacteria. In contrast, SERS spectra and viable bacterial number on Au NPs were rather constant under the same conditions. A further analysis on spectral changes demonstrated that it was cell response (i.e. metabolic activity or death) to the toxicity of Ag NPs causing spectral variance. However, biochemical responses to the toxicity of Ag were very different in different bacteria, indicating the complex toxic mechanism of Ag NPs. Ag NPs are toxic to a great variety of organisms, including bacteria, fungi, algae, protozoa etc., therefore, this work will be helpful in guiding the future application of SERS technique in various complex biological systems.

  5. SERS investigation of ciprofloxacin drug molecules on TiO2 nanoparticles.

    Science.gov (United States)

    Yang, Libin; Qin, Xiaoyu; Jiang, Xin; Gong, Mengdi; Yin, Di; Zhang, Yingjiu; Zhao, Bing

    2015-07-21

    In this paper, TiO2 nanoparticles (NPs) with different crystallinity served as SERS-active substrates for SERS detection of ciprofloxacin (CIP) drug molecules for the first time. CIP is close to the surface of the TiO2 substrate through the carboxyl group. The mutual SERS enhancement behaviors between CIP molecules and TiO2 NPs were discovered, which are attributed to the contribution of the TiO2-to-molecule charge-transfer mechanism. The crystallinity of TiO2 NPs, the pH value of adsorption solution and the adsorption time have significant influences on the interaction and the SERS behavior between CIP and TiO2. When the calcination temperature of TiO2 NPs is 450 °C, the pH value of adsorption solution is 6 and the adsorption time is 9 h, the CIP molecules on TiO2 NPs exhibit the largest SERS enhancement.

  6. Detection of Adhesion Molecules on Inflamed Macrophages at Early-Stage Using SERS Probe Gold Nanorods

    Institute of Scientific and Technical Information of China (English)

    Dakrong Pissuwan; Yusuke Hattori

    2017-01-01

    In recent years, it has been shown that inflammatory biomarkers can be used as an effective signal for disease diagnoses. The early detection of these signals provides useful information that could prevent the occurrence of severe diseases. Here, we employed surface-enhanced Raman scattering (SERS) probe gold nanorods (GNRs) as a tool for the early detection of inflammatory molecules in inflamed cells. A murine macrophage cell line (Raw264.7) stimulated with lipopolysaccharide (LPS) was used as a model in this study. The prepared SERS probe GNRs containing 4-mercapto-benzoic acid as a Raman reporter to generate SERS signals were used for detection of intracellular adhesion molecule-1 (ICAM-1) in macrophages after treatment with LPS for varying lengths of time. Our results show that SERS probe GNRs could detect significant differences in the expression of ICAM-1 molecules in LPS-treated macrophages compared to those in untreated macrophages after only 1 h of LPS treatment. In contrast, when using fluorescent labeling or enzyme-linked immunosorbent assays (ELISA) to detect ICAM-1, significant differences between inflamed and un-inflamed macrophages were not seen until the cells had been treated with LPS for 5 h. These results indicate that our SERS probe GNRs provide a higher sensitivity for detecting biomarker molecules in inflamed macrophages than the conventional fluorescence and ELISA techniques, and could therefore be useful as a potential diagnostic tool for managing disease risk.

  7. Phosphorylation of Rat Melanopsin at Ser-381 and Ser-398 by Light/Dark and Its Importance for Intrinsically Photosensitive Ganglion Cells (ipRGCs) Cellular Ca2+ Signaling*

    Science.gov (United States)

    Fahrenkrug, Jan; Falktoft, Birgitte; Georg, Birgitte; Hannibal, Jens; Kristiansen, Sarah B.; Klausen, Thomas K.

    2014-01-01

    The G protein-coupled light-sensitive receptor melanopsin is involved in non-image-forming light responses including circadian timing. The predicted secondary structure of melanopsin indicates a long cytoplasmic tail with many potential phosphorylation sites. Using bioinformatics, we identified a number of amino acids with a high probability of being phosphorylated. We generated antibodies against melanopsin phosphorylated at Ser-381 and Ser-398, respectively. The antibody specificity was verified by immunoblotting and immunohistochemical staining of HEK-293 cells expressing rat melanopsin mutated in Ser-381 or Ser-398. Using the antibody recognizing phospho-Ser-381 melanopsin, we demonstrated by immunoblotting and immunohistochemical staining in HEK-293 cells expressing rat melanopsin that the receptor is phosphorylated in this position during the dark and dephosphorylated when light is turned on. On the contrary, we found that melanopsin at Ser-398 was unphosphorylated in the dark and became phosphorylated after light stimulation. The light-induced changes in phosphorylation at both Ser-381 and Ser-398 were rapid and lasted throughout the 4-h experimental period. Furthermore, phosphorylation at Ser-381 and Ser-398 was independent of each other. The changes in phosphorylation were confirmed in vivo by immunohistochemical staining of rat retinas during light and dark. We further demonstrated that mutation of Ser-381 and Ser-398 in melanopsin-expressing HEK-293 cells affected the light-induced Ca2+ response, which was significantly reduced as compared with wild type. Examining the light-evoked Ca2+ response in a melanopsin Ser-381 plus Ser-398 double mutant provided evidence that the phosphorylation events were independent. PMID:25378407

  8. Ser-2030, but not Ser-2808, is the major phosphorylation site in cardiac ryanodine receptors responding to protein kinase A activation upon beta-adrenergic stimulation in normal and failing hearts.

    Science.gov (United States)

    Xiao, Bailong; Zhong, Guofeng; Obayashi, Masakazu; Yang, Dongmei; Chen, Keyun; Walsh, Michael P; Shimoni, Yakhin; Cheng, Heping; Ter Keurs, Henk; Chen, S R Wayne

    2006-05-15

    We have recently shown that RyR2 (cardiac ryanodine receptor) is phosphorylated by PKA (protein kinase A/cAMP-dependent protein kinase) at two major sites, Ser-2030 and Ser-2808. In the present study, we examined the properties and physiological relevance of phosphorylation of these two sites. Using site- and phospho-specific antibodies, we demonstrated that Ser-2030 of both recombinant and native RyR2 from a number of species was phosphorylated by PKA, indicating that Ser-2030 is a highly conserved PKA site. Furthermore, we found that the phosphorylation of Ser-2030 responded to isoproterenol (isoprenaline) stimulation in rat cardiac myocytes in a concentration- and time-dependent manner, whereas Ser-2808 was already substantially phosphorylated before beta-adrenergic stimulation, and the extent of the increase in Ser-2808 phosphorylation after beta-adrenergic stimulation was much less than that for Ser-2030. Interestingly, the isoproterenol-induced phosphorylation of Ser-2030, but not of Ser-2808, was markedly inhibited by PKI, a specific inhibitor of PKA. The basal phosphorylation of Ser-2808 was also insensitive to PKA inhibition. Moreover, Ser-2808, but not Ser-2030, was stoichiometrically phosphorylated by PKG (protein kinase G). In addition, we found no significant phosphorylation of RyR2 at the Ser-2030 PKA site in failing rat hearts. Importantly, isoproterenol stimulation markedly increased the phosphorylation of Ser-2030, but not of Ser-2808, in failing rat hearts. Taken together, these observations indicate that Ser-2030, but not Ser-2808, is the major PKA phosphorylation site in RyR2 responding to PKA activation upon beta-adrenergic stimulation in both normal and failing hearts, and that RyR2 is not hyperphosphorylated by PKA in heart failure. Our results also suggest that phosphorylation of RyR2 at Ser-2030 may be an important event associated with altered Ca2+ handling and cardiac arrhythmia that is commonly observed in heart failure upon beta

  9. Ser-2030, but not Ser-2808, is the major phosphorylation site in cardiac ryanodine receptors responding to protein kinase A activation upon β-adrenergic stimulation in normal and failing hearts

    Science.gov (United States)

    Xiao, Bailong; Zhong, Guofeng; Obayashi, Masakazu; Yang, Dongmei; Chen, Keyun; Walsh, Michael P.; Shimoni, Yakhin; Cheng, Heping; ter Keurs, Henk; Chen, S. R. Wayne

    2006-01-01

    We have recently shown that RyR2 (cardiac ryanodine receptor) is phosphorylated by PKA (protein kinase A/cAMP-dependent protein kinase) at two major sites, Ser-2030 and Ser-2808. In the present study, we examined the properties and physiological relevance of phosphorylation of these two sites. Using site- and phospho-specific antibodies, we demonstrated that Ser-2030 of both recombinant and native RyR2 from a number of species was phosphorylated by PKA, indicating that Ser-2030 is a highly conserved PKA site. Furthermore, we found that the phosphorylation of Ser-2030 responded to isoproterenol (isoprenaline) stimulation in rat cardiac myocytes in a concentration- and time-dependent manner, whereas Ser-2808 was already substantially phosphorylated before β-adrenergic stimulation, and the extent of the increase in Ser-2808 phosphorylation after β-adrenergic stimulation was much less than that for Ser-2030. Interestingly, the isoproterenol-induced phosphorylation of Ser-2030, but not of Ser-2808, was markedly inhibited by PKI, a specific inhibitor of PKA. The basal phosphorylation of Ser-2808 was also insensitive to PKA inhibition. Moreover, Ser-2808, but not Ser-2030, was stoichiometrically phosphorylated by PKG (protein kinase G). In addition, we found no significant phosphorylation of RyR2 at the Ser-2030 PKA site in failing rat hearts. Importantly, isoproterenol stimulation markedly increased the phosphorylation of Ser-2030, but not of Ser-2808, in failing rat hearts. Taken together, these observations indicate that Ser-2030, but not Ser-2808, is the major PKA phosphorylation site in RyR2 responding to PKA activation upon β-adrenergic stimulation in both normal and failing hearts, and that RyR2 is not hyperphosphorylated by PKA in heart failure. Our results also suggest that phosphorylation of RyR2 at Ser-2030 may be an important event associated with altered Ca2+ handling and cardiac arrhythmia that is commonly observed in heart failure upon

  10. Substitutions of Ser83Leu in GyrA and Ser80Leu in ParC Associated with Quinolone Resistance in Acinetobacter pittii.

    Science.gov (United States)

    Gu, Dan-xia; Hu, Yun-jian; Zhou, Hong-wei; Zhang, Rong; Chen, Gong-xiang

    2015-06-01

    To investigate the prevalence and the mechanism of quinolone-resistant Acinetobacter pittii, 634 Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolates were collected throughout Zhejiang Province. Identification of isolates was conducted by matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS), blaOXA-51-like gene, and partial RNA polymerase β-subunit (rpoB) amplification. Twenty-seven isolates of A. pittii were identified. Among the 634 isolates, A. baumannii, A. pittii, Acinetobacter nosocomialis, and A. calcoaceticus counted for 87.22%, 4.26%, 8.20%, and 0.32%, respectively. Antimicrobial susceptibility of nalidixic acid, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, levofloxacin, sparfloxacin, moxifloxacin, and gatifloxacin for 27 A. pittii were determined by the agar dilution method. Detection of quinolone-resistant determining regions of gyrA, gyrB, parC, and parE was performed for the A. pittii isolates. In addition, plasmid-mediated quinolone resistance (PMQR) determinants (qnrA, qnrB, qnrS, qnrC, qnrD, aac(6')-Ib-cr, qepA, oqxA, and oqxB) were investigated. All the 27 isolates demonstrated a higher minimum inhibitory concentration (MIC) to old quinolones than the new fluoroquinolones. No mutation in gyrA, gyrB, parC, or parE was detected in 20 ciprofloxacin-susceptible isolates. Seven ciprofloxacin-resistant A. pittii were identified with a Ser83Leu mutation in GyrA. Among them, six isolates with simultaneous Ser83Leu amino acid substitution in GyrA and Ser80Leu in ParC displayed higher MIC values against ciprofloxacin. Additionally, three were identified with a Met370Ile substitution in ParE, and two were detected with a Tyr317His mutation in ParE, which were reported for the first time. No PMQR determinants were identified in the 27 A. pittii isolates. In conclusion, mutations in chromosome play a major role in quinolone resistance in A. pittii, while resistance mechanisms mediated by plasmid have

  11. Reproducible and recyclable SERS substrates: Flower-like Ag structures with concave surfaces formed by electrodeposition

    Science.gov (United States)

    Bian, Juncao; Shu, Shiwei; Li, Jianfu; Huang, Chao; Li, Yang Yang; Zhang, Rui-Qin

    2015-04-01

    Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 108, exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates.

  12. Tatuajes y su eliminación por láser

    Directory of Open Access Journals (Sweden)

    T. Castro

    Full Text Available La eliminación de los tatuajes con buen resultado cosmético ha sido una inquietud mantenida durante siglos. La introducción del tratamiento láser ha supuesto un avance importante de cara a obtener buenos resultados con mínimos efectos secundarios. En este trabajo se exponen los diferentes tipos de tatuajes con sus características de pigmento, origen, tipos de tratamientos para su eliminación, y entre ellos, la utilización de la tecnología láser, más concretamente de los láseres de emisión en Q-Switch con sus ventajas y limitaciones. Presentamos también los avances y el futuro de la aplicación del láser en el tratamiento de los tatuajes.

  13. Ultra-thin layer chromatography with integrated silver colloid-based SERS detection.

    Science.gov (United States)

    Wallace, Ryan A; Lavrik, Nickolay V; Sepaniak, Michael J

    2017-01-01

    Simplified lab-on-a-chip techniques are desirable for quick and efficient detection of analytes of interest in the field. The following work involves the use of deterministic pillar arrays on the micro-scale as a platform to separate compounds, and the use of Ag colloid within the arrays as a source of increased signal via surface enhanced Raman spectroscopy (SERS). One problem traditionally seen with SERS surfaces containing Ag colloid is oxidation; however, our platforms are superhydrophobic, reducing the amount of oxidation taking place on the surface of the Ag colloid. This work includes the successful separation and SERS detection of a fluorescent dye compounds (resorufin and sulforhodamine 640), fluorescent anti-tumor drugs (Adriamycin and Daunomycin), and purine and pyrimidine bases (adenine, cytosine, guanine, hypoxanthine, and thymine). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Wavelength modulated SERS hot spot distribution in 1D nanostructures on metal film

    Science.gov (United States)

    Wang, Lili; Zeng, Xiping; Liu, Ting; Zhang, Xuemei; Wei, Hua; Huang, Yingzhou; Liu, Anping; Wang, Shuxia; Wen, Weijia

    2016-10-01

    Surface plasmons confining strong electromagnetic fields near metal surfaces, well-known as hot spots, provide an extremely efficient platform for surface-enhanced Raman scattering (SERS). In this work, SERS spectra of probing molecules in a silver particle-wire 1D nanostructure on a thin gold film are investigated. The Raman features of SERS spectra collected at the particle-wire joints exhibit an obvious wavelength dependence phenomenon. This result is confirmed electromagnetic field simulation, revealing that hot spot distribution is sensitively influenced by the wavelength of incident light at the joints. Further studies indicate this wavelength dependence of hot spot distribution is immune to influence from the geometric shape of the particle or the angle between wire and particle, which improves fabrication tolerance. This technology may have promising applications in surface plasmon related fields, such as ultrasensors, solar energy and selective surface catalysis.

  15. Contractions induce phosphorylation of the AMPK site Ser565 in hormone-sensitive lipase in muscle

    DEFF Research Database (Denmark)

    Donsmark, Morten; Langfort, Jozef; Holm, Cecilia;

    2004-01-01

    Intramyocellular triglyceride is an important energy store which is related to insulin resistance. Mobilization of fatty acids from this pool is probably regulated by hormone-sensitive lipase (HSL), which has recently been shown to exist in muscle and to be activated by epinephrine via PKA...... and by contractions via PKC and ERK. 5' AMP-activated protein kinase (AMPK) is an intracellular fuel gauge which regulates metabolism. In this study we incubated rat soleus muscle to investigate if AMPK influences HSL during 5min of repeated tetanic contractions. An eightfold increase in AMPK activity was accompanied...... by a 2.5-fold increase in phosphorylation of the AMPK-site Ser(565) in HSL (pHSL activation while HSL-Ser(565) phosphorylation was not reduced. The study indicates that during contractions AMPK phosphorylates HSL in Ser(565...

  16. Bioorthogonal SERS Nanoprobes for Mulitplex Spectroscopic Detection, Tumor Cell Targeting, and Tissue Imaging.

    Science.gov (United States)

    Wu, Junzhou; Liang, Duanwei; Jin, Qingqing; Liu, Jie; Zheng, Meiling; Duan, Xuanming; Tang, Xinjing

    2015-09-07

    A surface-enhanced Raman scattering (SERS) technique shows extraordinary features for a range of biological and biomedical applications. Herein, a series of novel bioorthogonal SERS nanoprobes were constructed with Gold nanoflower (AuNF) and Raman reporters, the signals of which were located in a Raman-silent region of biological samples. AS1411 aptamer was also co-conjugated with AuNF through a self-assembled monolayer coverage strategy. Multiplex SERS imaging using these nanoprobes with three different bioorthogonal small-molecule Raman reporters is successfully achieved with high multiplexing capacity in a biologically Raman-silent region. These Raman nanoprobes co-conjugated with AS1411 showed high affinity for tumor cells with overexpressed nucleolin and can be used for selective tumor cell screening and tissue imaging.

  17. Synthesis of Dendritic Silver Nanoparticles and Their Applications as SERS Substrates

    Directory of Open Access Journals (Sweden)

    Jinshan Yu

    2013-01-01

    Full Text Available The silver nanoparticles are synthesized by electrodeposition in ultradilute Ag+ concentration electrolyte under high overpotential. The as prepared Ag nanoparticles, with the sizes ranging from 20 to 30 nm, are arrayed orderly and formed dendritic morphology. The formation of this special dendritic nanoparticle structure can be contributed to the relatively high growth rate and the preferential growth directions along 111 due to the high overpotential, as well as the relative small number of Ag+ ions arriving at the Ag crystal surface per unit time due to the ultradilute Ag+ concentration. Surface enhanced Raman scattering (SERS experiments reveal that the as-prepared dendritic Ag nanoparticles possess high SERS properties and can be used as a candidate substrate for practical SERS applications to detect the Rhodamine 6G molecules.

  18. Designing of a novel gold nanodumbbells SERS substrate for detection of prohibited colorants in drinks

    Science.gov (United States)

    Meng, Juan; Qin, Suhua; Zhang, Li; Yang, Liangbao

    2016-03-01

    It is reported that the use of gold nanodumbbells as surface-enhanced Raman spectroscopy (SERS) substrates for the detection of ultra-low levels of four different food colorants: sunset yellow, lemon yellow, orange II and chrysoidin. Gold nanodumbbells are suitable to on-site detection because which have a λmax of 785 nm that tune the surface plasmon resonance of the nanoparticles to the laser excitation wavelength of the Raman spectrometer equipped with a 785 nm diode laser. In order to investigate the on-site application of the gold nanodumbbells substrate, four pigments in the orange juice and coke were detected by the portable Raman instrument. The results showed that this novel SERS platform can be used as an effective method in detecting prohibited additive colorants in food. This SERS platform provides valuable and powerful analytical tool in real-world applications in food analysis.

  19. IR, Raman and SERS spectra of 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzene carboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Asha [Government Polytechnic Coll., Attingal, Kerala (India). Dept. of Physics; Raju, K. [University College, Trivandrum, Kerala (India). Dept. of Physics; Varghese, Hema Tresa [Fatima Mata National Coll., Kollam, Kerala (India). Dept. of Physics; Granadeiro, Carlos M.; Nogueira, Helena I. S. [University of Aveiro (Portugal). Centro de Investigacao em Materiais Ceramicos e Compositos (CICECO). Dept. of Chemistry; Panicker, C. Yohannan [TKM College of Arts and Science, Kollam, Kerala (India). Dept. of Physics]. E-mail: cyphyp@rediffmail.com

    2009-07-01

    2-(Methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylic acid was prepared by nucleophilic substitution. FT-IR and FT-Raman spectra of 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylic acid were recorded and analyzed. Surface enhanced Raman scattering (SERS) spectrum was recorded on a silver colloid. The vibrational wavenumbers were computed by density functional theoretical (DFT) computations at the B3LYP/6-31G{sup *} level and they were found to be in good agreement with the experimental values. Significant metal-molecule interaction has been substantiated by the appearance of intense Ag-O mode in the SERS spectrum and this is indicative of the nearness of nitro and carbonyl group to the silver surface. SERS studies suggest a tilted orientation of the molecule at the metal surface. (author)

  20. Investigation of 1D Siliver Nanoparticle Arrays for Use as Molecule Concentration-Specific SERS Substrates

    Directory of Open Access Journals (Sweden)

    Jun Gao

    2013-01-01

    Full Text Available One-dimensional arrays of silver nanoparticles with a particle size of 10.5 nm and interparticle spacing of 8.5 nm were fabricated by depositing nanoparticles in gas phase on block copolymer self-assembled templates. The substrate showed a surface-enhanced Raman scattering (SERS enhancement factor as high as 1×107 with good reproducibility and stability. The dependence of the average enhancement factor and the SERS intensity on the packing density of the analyte molecules were investigated. For a tiny amount of analytes in the range of 1×10-14 to 3×10-13 mol/mm2, the SERS signal showed a linear dependence on the molecule packing density on a logarithmic scale, with a slope of about 1.25. The substrates are promising for quantitative detection of trace level molecules.

  1. A keratin 9 Gene mutation (Asn160Ser) in a Japanese patient with epidermolytic palmoplantar keratoderma.

    Science.gov (United States)

    Tsunemi, Yuichiro; Hattori, Naoko; Saeki, Hidehisa; Adachi, Makoto; Komine, Mayumi; Nakagawa, Hidemi; Tamaki, Kunihiko

    2002-12-01

    We described a 5-year-old Japanese girl with epidermolytic palmoplantar keratoderma and examined her for a keratin 9 gene mutation. Physical examination disclosed diffuse yellowish hyperkeratosis with an erythematous border limited strictly to the palms and soles. Histological examination revealed hyperkeratosis with vacuolar degeneration in the spinous and granular layers of the epidermis. Sequence analysis demonstrated an A to G transition at the middle position of codon 160 in the 1A domain of the keratin 9 gene. The amino acid at codon 160 was deduced to have changed from asparagine (Asn) to serine (Ser). This is the first case with an Asn160Ser mutation in a Japanese. The substitution of Ser for Asn at codon 160 of the keratin 9 gene is assumed to be fatal for keratin filament assembly regardless of race or ethnicity.

  2. [Molecular analysis of the p.Asn 370 Ser mutation in Gaucher disease].

    Science.gov (United States)

    Dandana, A; Ferchichi, S; Ben Khelifa, S; Jaidane, Z; Monastiri, K; Chkioua, L; Maire, I; Froissart, R; Bonnet, V; Laradi, S; Miled, A

    2008-03-01

    Gaucher disease is one of the most prevalent lysosomal disorders. In this present study, we report a diagnostic strategy of type 1 Gaucher disease. The application of combined methods in molecular biology allowed us to analyse the p.Asn 370 Ser mutation. The affected individual activity is very low. First, we have to used the enzymatic digestion method. Then, we have to identified the mutation by the refractory mutation system technique using specific primers for the p.Asn 370 Ser mutation. These analyses are supplemented by the direct sequencing in order to seek and confirm this mutation. Finally, the absence of the 55 pb deletion in exon 9 among corroborated the presence of the homozygous genotype of this p.Asn 370 Ser in the patient DNA.

  3. Controllable SERS performance for the flexible paper-like films of reduced graphene oxide

    Science.gov (United States)

    Yan, Taotao; Zhang, Lili; Jiang, Tongtong; Bai, Zhiman; Yu, Xinxin; Dai, Peng; Wu, Mingzai

    2017-10-01

    paper-like films of reduced graphene oxide with controllable shapes and thickness were prepared via funnel filtration and thermal reduction of graphene oxide (GO), which could work as flexible surface-enhanced Raman scattering (SERS) substrates to detect Rhodamine 6G (R6G) molecules. The SERS signal intensity of R6G on annealed films was found to be related with the annealling temperature. The most intense signal was observed for the film obtained at 800 °C. While for the sample annealed at 1000 °C, no SERS signal could be detected. The underlying mechanism for the difference was discussed. The reported preparation process of flexible rGO paper is simple and cost-effective, which shows great potential in rapid biochemical analysis of agricultural products with irregular surfaces.

  4. A unidade entre o ser e o pensar na Ciência da Lógica

    Directory of Open Access Journals (Sweden)

    Tomás Farcic Menk

    2017-02-01

    Full Text Available Este artigo tem como objetivo analisar uma relação básica sobre a qual a Ciência da Lógica está fundamentada, a saber, a unidade entre o ser e o pensar. Hegel afirma, ainda na introdução a obra, que a filosofia deve ter início sem nenhuma pressuposição prévia e, portanto, partir do puro ser totalmente indeterminado. Porém, sendo a lógica a ciência do pensar sobre o pensar, este ser inicial nada mais é do que a primeira posição do pensar e, assim sendo, este puro ser também é um puro pensar, totalmente indeterminado. Desta forma, se tem uma unidade entre ser e pensar, e esta unidade é que será desenvolvida através dos momentos da Ciência da Lógica. Porém, ela não permanece imutável ou inalterada, como Hegel acusa a antiga metafísica, identificada na figura de Descartes, Leibniz e Wolff. Muito antes, ela é mediatizada pelo entendimento, que separa estas duas instâncias e as relaciona. Ao se relacionarem, elas se descobrem como idênticas e surge novamente uma identidade, mas agora não indiferenciada, mas que se conhece e que se sabe como unidade, pois se elevou da certeza à verdade. Por fim, utilizaremos esta leitura de Hegel para contrapor a interpretação de Pippin, tal como expressa na obra Hegels Idealism.

  5. Quaternized chitosan/silver nanoparticles composite as a SERS substrate for detecting tricyclazole and Sudan I

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kaihang; Shen, Zuguang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Jiwen, E-mail: holdit@126.com [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Xiaoying, E-mail: xyw@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Sun, Runcang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Institute of Biomass Chemistry and Technology, Beijing Forestry University, Beijing 100083 (China)

    2015-10-01

    Graphical abstract: - Highlights: • Synthesis optimization of Ag NPs with quaternized chitosan (QCS) was studied. • The size of Ag NPs was tuned by changing the DS and Mw of QCS. • QCS/Ag NPs exhibited much better SERS performance than Ag NPs without free QCS. • QCS/Ag NPs as SERS substrate detected tricyclazole in low concentration of 50 ppb. • QCS/Ag NPs as SERS substrate detected Sudan I with the detection limit of 10 ppm. - Abstract: There is an urgent need to develop a highly sensitive detection system for detecting trace amounts of food contaminants. In this study, optimal synthesis of silver nanoparticles (Ag NPs) with stable and narrow size distribution in the range of 15–25 nm was performed under microwave irradiation, using quaternized chitosan (QCS) as reducing and stabilizing agent. The results showed that the ratio of QCS to [Ag(NH{sub 3}){sub 2}]{sup +}, reaction temperature, irradiation time, the degree of substitution (DS) and molecular weight (Mw) of QCS had obvious effects on the formation, particle size and size distribution of Ag NPs. In addition, utilizing QCS/Ag NPs composite as SERS substrate, tricyclazole and Sudan I could be rapidly and sensitively detected with the limit of detection (LOD) as low as 50 ppb and 10 ppm, respectively. Compared with previously reported works, our detection system are of great stability and operability. The QCS was coated on the surface of Ag core, avoiding aggregation of Ag NPs and creating hot spots, in turn, providing superior amplification of SERS. Thus, it is believed that the QCS/Ag NPs composite could be considered as an ideal SERS-active substrate for detection of food contaminants.

  6. SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers

    Science.gov (United States)

    Marks, Haley; Mabbott, Samuel; Jackson, George W.; Graham, Duncan; Cote, Gerard L.

    2015-03-01

    Functionalized colloidal nanoparticles for SERS serve as a promising multifunctional assay component for blood biomarker detection. Proper design of these nanoprobes through conjugation to spectral tags, protective polymers, and sensing ligands can provide experimental control over the sensitivity, range, reproducibility, particle stability, and integration with biorecognition assays. Additionally, the optical properties and degree of electromagnetic SERS signal enhancement can be altered and monitored through tuning the nanoparticle shape, size, material and the colloid's local surface plasmon resonance (LSPR). Aptamers, synthetic affinity ligands derived from nucleic acids, provide a number of advantages for biorecognition of small molecules and toxins with low immunogenicity. DNA aptamers are simpler and more economical to produce at large scale, are capable of greater specificity and affinity than antibodies, are easily tailored to specific functional groups, can be used to tune inter-particle distance and shift the LSPR, and their intrinsic negative charge can be utilized for additional particle stability.1,2 Herein, a "turn-off" competitive binding assay platform involving two different plasmonic nanoparticles for the detection of the toxin bisphenol A (BPA) using SERS is presented. A derivative of the toxin is immobilized onto a silver coated magnetic nanoparticle (Ag@MNP), and a second solid silver nanoparticle (AgNP) is functionalized with the BPA aptamer and a Raman reporter molecule (RRM). The capture (Ag@MNP) and probe (AgNP) particles are mixed and the aptamer binding interaction draws the nanoparticles closer together, forming an assembly that results in an increased SERS signal intensity. This aptamer mediated assembly of the two nanoparticles results in a 100x enhancement of the SERS signal intensity from the RRM. These pre-bound aptamer/nanoparticle conjugates were then exposed to BPA in free solution and the competitive binding event was monitored

  7. Development of nanostars as a biocompatible tumor contrast agent: toward in vivo SERS imaging

    Directory of Open Access Journals (Sweden)

    D’Hollander A

    2016-08-01

    Full Text Available Antoine D’Hollander,1–3 Evelien Mathieu,1,4 Hilde Jans,1 Greetje Vande Velde,2,3 Tim Stakenborg,1 Pol Van Dorpe,1,4 Uwe Himmelreich,2,3 Liesbet Lagae1,4 1Department of Life Science Technology, Imec, 2Department of Imaging and Pathology, Faculty of Medicine, Biomedical MRI Unit, 3Faculty of Medicine, Molecular Small Animal Imaging Center (MoSAIC, 4Department of Physics, Faculty of Sciences, Laboratory of Solid State Physics and Magnetism, KU Leuven, Leuven, Belgium Abstract: The need for sensitive imaging techniques to detect tumor cells is an important issue in cancer diagnosis and therapy. Surface-enhanced Raman scattering (SERS, realized by chemisorption of compounds suitable for Raman spectroscopy onto gold nanoparticles, is a new method for detecting a tumor. As a proof of concept, we studied the use of biocompatible gold nanostars as sensitive SERS contrast agents targeting an ovarian cancer cell line (SKOV3. Due to a high intracellular uptake of gold nanostars after 6 hours of exposure, they could be detected and located with SERS. Using these nanostars for passive targeting after systemic injection in a xenograft mouse model, a detectable signal was measured in the tumor and liver in vivo. These signals were confirmed by ex vivo SERS measurements and darkfield microscopy. In this study, we established SERS nanostars as a highly sensitive contrast agent for tumor detection, which opens the potential for their use as a theranostic agent against cancer. Keywords: SERS, gold nanostars, cancer imaging, Raman active

  8. Paper membrane-based SERS platform for the determination of glucose in blood samples.

    Science.gov (United States)

    Torul, Hilal; Çiftçi, Hakan; Çetin, Demet; Suludere, Zekiye; Boyacı, Ismail Hakkı; Tamer, Uğur

    2015-11-01

    In this report, we present a paper membrane-based surface-enhanced Raman scattering (SERS) platform for the determination of blood glucose level using a nitrocellulose membrane as substrate paper, and the microfluidic channel was simply constructed by wax-printing method. The rod-shaped gold nanorod particles were modified with 4-mercaptophenylboronic acid (4-MBA) and 1-decanethiol (1-DT) molecules and used as embedded SERS probe for paper-based microfluidics. The SERS measurement area was simply constructed by dropping gold nanoparticles on nitrocellulose membrane, and the blood sample was dropped on the membrane hydrophilic channel. While the blood cells and proteins were held on nitrocellulose membrane, glucose molecules were moved through the channel toward the SERS measurement area. Scanning electron microscopy (SEM) was used to confirm the effective separation of blood matrix, and total analysis is completed in 5 min. In SERS measurements, the intensity of the band at 1070 cm(-1) which is attributed to B-OH vibration decreased depending on the rise in glucose concentration in the blood sample. The glucose concentration was found to be 5.43 ± 0.51 mM in the reference blood sample by using a calibration equation, and the certified value for glucose was 6.17 ± 0.11 mM. The recovery of the glucose in the reference blood sample was about 88 %. According to these results, the developed paper-based microfluidic SERS platform has been found to be suitable for use for the detection of glucose in blood samples without any pretreatment procedure. We believe that paper-based microfluidic systems may provide a wide field of usage for paper-based applications.

  9. Project W-320, waste retrieval sluicing system: BIO/SER implementation matrices

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.W.

    1998-07-25

    This document provides verification that the safety related commitments specified in HNF-SD-WM-810-001, Addendum 1 for the Waste Retrieval Sluicing System, Project W-320 and Project W-320 Safety Evaluation Report (SER), have been implemented in the project hardware, procedures and administrative controls. Four appendices include matrices which show where the 810 commitments are implemented for limiting conditions of operation and surveillance requirements controls, administrative controls, defense-in-depth controls and controls discussed in 810 Addendum 1. A fifth appendix includes the implementation of Project W-320 SER issues and provisions.

  10. El láser CO2 y sus aplicaciones en oftalmología veterinaria

    OpenAIRE

    Torrubia, I.; Marvá, N.; Espuch, P.

    2012-01-01

    El LASER (Light Amplification by Stimulated Emision of Radiation) es una fuente de energía descubierta a finales de los años 50 que se emplea en multitud de campos y que ha evolucionado constantemente desde entonces, obteniéndose multitud de tipos de láser en función de la longitud de onda con la que se trabaje. Este gran avance no puede dejar de tener sus aplicaciones en la medicina. Este artículo hace una referencia básica sobre los diferentes tipos de láser y sus características, tratando ...

  11. Rough SERS substrate based on gold coated porous silicon layer prepared on the silicon backside surface

    Science.gov (United States)

    Dridi, H.; Haji, L.; Moadhen, A.

    2017-04-01

    We report in this paper a novel method to elaborate rough Surface Enhanced Raman Scattering (SERS) substrate. A single layer of porous silicon was formed on the silicon backside surface. Morphological characteristics of the porous silicon layer before and after gold deposition were influenced by the rough character (gold size). The reflectance measurements showed a dependence of the gold nano-grains size on the surface nature, through the Localized Surface Plasmon (LSP) band properties. SERS signal of Rhodamine 6G used as a model analyte, adsorbed on the rough porous silicon layer revealed a marked enhancement of its vibrational modes intensities.

  12. Efecto bactericida del láser de diodo en periodoncia

    OpenAIRE

    G Caccianiga; Urso, E.; R Monguzzi; Gallo, K.; G. Rey

    2007-01-01

    El láser en odontología, gracias a su capacidad antibacteriana, hemostática y de menor sintomatología operatoria, encuentra un amplio campo de aplicación en el ámbito de la terapia periodontal. En este estudio ha sido probada la eficacia de un protocolo que prevé la utilización asociada de irradiación láser y de agua oxigenada con el fin de reducir a carga bacteriana de cepas comúnmente presentes en las bolsas periodontales activas y resistentes a la acción bactericida de solamente la irradia...

  13. Nanostructured Silver Substrates With Stable and Universal SERS Properties: Application to Organic Molecules and Semiconductor Nanoparticles

    Directory of Open Access Journals (Sweden)

    Waurisch C

    2009-01-01

    Full Text Available Abstract Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60–80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time.

  14. Dynamic SERS imaging of cellular transport pathways with endocytosed gold nanoparticles.

    Science.gov (United States)

    Ando, Jun; Fujita, Katsumasa; Smith, Nicholas I; Kawata, Satoshi

    2011-12-14

    Dynamic SERS imaging inside a living cell is demonstrated with the use of a gold nanoparticle, which travels through the intracellular space to probe local molecular information over time. Simultaneous tracking of particle motion and SERS spectroscopy allows us to detect intracellular molecules at 65 nm spatial resolution and 50 ms temporal resolution, providing molecular maps of organelle transport and lisosomal accumulation. Multiplex spectral and trajectory imaging will enable imaging of specific dynamic biological functions such as membrane protein diffusion, nuclear entry, and rearrangement of cellular cytoskeleton.

  15. Ser educador(a é ... (também socializar inquietações

    Directory of Open Access Journals (Sweden)

    Sandra Marisa Allebrandt-Padilha

    2011-11-01

    Full Text Available O presente artigo convida os educadores a refletir sobre questões candentes do cotidiano escolar, tais como: o sofrimento diante do aluno que não aprende, o mal-estar-docente decorrente das transformações sociopolíticas que convergem para a Educação Inclusiva. Nessa perspectiva, com o propósito de buscar respostas para a Educação na Diversidade, elegemos algumas iniciativas que desafiam aqueles que desejam ser protagonistas no ofício SER EDUCADOR.Palavras-chave: Cotidiano Escolar. Dificuldade de Aprendizagem. Educação Inclusiva, Mal-Estar-Docente. Diversidade..

  16. Aplicaciones del láser Doppler en odontología

    OpenAIRE

    Pérez-García, Sílvia; Paredes García, Jordi; Berini Aytés, Leonardo; Gay Escoda,Cosme

    2002-01-01

    El flujómetro de láser Doppler es un método no invasivo que proporciona una medida continua del registro del flujo sanguíneo a nivel microvascular. Un haz de luz láser incidente en cualquier tejido humano, es dispersado tanto en las estructuras estáticas como por los glóbulos rojos. Los haces devueltos por los glóbulos rojos sufren una desviación en su frecuencia de acuerdo con el efecto Doppler, mientras que los dispersos por el tejido estático permanecen inalterados. Ambas fracciones de luz...

  17. Aplicaciones del láser Doppler en odontología

    OpenAIRE

    Pérez-García, Sílvia; Paredes García, Jordi; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2002-01-01

    El flujómetro de láser Doppler es un método no invasivo que proporciona una medida continua del registro del flujo sanguíneo a nivel microvascular. Un haz de luz láser incidente en cualquier tejido humano, es dispersado tanto en las estructuras estáticas como por los glóbulos rojos. Los haces devueltos por los glóbulos rojos sufren una desviación en su frecuencia de acuerdo con el efecto Doppler, mientras que los dispersos por el tejido estático permanecen inalterados. Ambas fracciones de luz...

  18. First observation of Hb Tunis [beta124(H2)Pro>Ser] in Turkey

    OpenAIRE

    Aylin Köseler; Hasan Koyuncu; Onur Öztürk; Anzel Bahadır; Sanem Demirtepe; Ayfer Atalay; Erol Ömer Atalay

    2010-01-01

    Hb Tunis [beta124(H2)Pro>Ser] was reported from Tunisia in 1988. This hemoglobin variant was detected by isoelectric focusing moving just ahead of Hb A. It cannot be identified by standard hemoglobin electrophoresis due to its similar mobility to Hb A. It has normal stability and oxygen affinity and does not produce any clinical symptoms. Here, we report a heterozygous Hb Tunis [beta124(H2)Pro>Ser] case discovered for the first time in Turkey in a premarital screening program. This hemoglobin...

  19. La angustia del ser y del deber en la tragedia griega

    OpenAIRE

    David García Pérez

    2008-01-01

    En este trabajo se explora la definición de lo trágico partiendo de la comprensión de la angustia en algunas tragedias griegas. El sentimiento de la angustia nace cuando el sujeto se ve obligado a definir su ser, hecho que se opone la mayoría de las veces a su deber; en la confrontación de ser y de deber, nace la tensión trágica que se revela, entre otros procesos, con la máscara y la metamorfosis.

  20. Efecto bactericida del láser de diodo en periodoncia

    Directory of Open Access Journals (Sweden)

    G Caccianiga

    2007-12-01

    Full Text Available El láser en odontología, gracias a su capacidad antibacteriana, hemostática y de menor sintomatología operatoria, encuentra un amplio campo de aplicación en el ámbito de la terapia periodontal. En este estudio ha sido probada la eficacia de un protocolo que prevé la utilización asociada de irradiación láser y de agua oxigenada con el fin de reducir a carga bacteriana de cepas comúnmente presentes en las bolsas periodontales activas y resistentes a la acción bactericida de solamente la irradiación láser como la Prevotella intermedia, Fusobacterium nucleatum y Peptostreptococcus micron. La metodología de laboratorio preveía el siguiente protocolo: cada una de las suspensiones bacterianas ha sido expuesta al agua oxigenada a una concentración del 3% y ha sido irradiada con láser por 10, 15 o 20 segundos utilizando tubos estériles Eppendorf de 1,5 ml. Los resultados confirman la mayor eficacia bactericida de la acción combinada de agua oxigenada y láser. Los cultivos microbiológicos efectuados revelan como, no obstante el efecto bactericida, el láser tiene una escasa acción sobre las cepas bacterianas testadas si no es asociado al agua oxigenada. En particular, en el caso de la Prevotela intermedia y del Fusobacterium nucleatum, la utilización de agua oxigenada al 3% solamente ha dado resultado mejores respecto a solamente el láser, mientras que la asociación de los dos tratamientos ha dado siempre óptimos resultados. En el caso del Peptostreptococcus micron, la utilización de agua oxigenada y el láser separadamente han dado una escasa disminución de la cuenta bacteriana mientras que la asociación de los tratamientos ha potenciado la acción bactericida.

  1. Aplicaciones del láser blando en odontología

    OpenAIRE

    Trullols Casas, C.; España Tost, A. J. (Antonio Jesús); Berini Aytés, Leonardo; Gay Escoda, Cosme

    1997-01-01

    Las principales aplicaciones del láser blando en Odontología son como analgésico, antiinflamatorio, cicatrizante y hemostático. Algunos estudios in vitro parecen demostrar que el láser blando modifica ciertas reacciones a nivel bioquímico, pero a la hora de su aplicación clínica no hay unanimidad respecto a su efectividad ya que, frente a los estudios cuyos resultados son positivos, están los que no los obtienen y lo relacionan a un posible efecto placebo. A esta controversia se suma el hecho...

  2. Adsorption of CGA on colloidal silver particles: DFT and SERS study

    Science.gov (United States)

    Biswas, Nandita; Kapoor, Sudhir; Mahal, Harbir S.; Mukherjee, Tulsi

    2007-08-01

    Raman and surface-enhanced Raman scattering (SERS) of chlorogenic acid (CGA) have been investigated. CGA is an important plant metabolite with anti-viral and anti-bacterial properties and thus, it is useful to study its surface adsorption characteristics. The experimental Raman data is supported with DFT calculations using B3LYP functional with 6-31G ∗ and LANL2DZ basis set. This is the first report on the vibrational analysis of CGA and its silver complex. From the SERS spectra as well as theoretical calculations, it has been inferred that the molecule is chemisorbed to the silver surface through the oxygen atoms of the carboxylate group.

  3. Rapid multiplexed molecular phenotyping of ex vivo and in vivo tissues with targeted SERS NPs

    Science.gov (United States)

    Wang, Yu; Khan, Altaz; Som, Madhura; Leigh, Steven Y.; Wang, Danni; Chen, Ye; McVeigh, Patrick; Wilson, Brian C.; Liu, Jonathan T. C.

    2014-05-01

    We are developing a miniature fiber-optic spectral-detection device and topical-staining protocol to rapidly detect multiplexed surface-enhanced Raman scattering (SERS) nanoparticles (NPs) targeted to cell-surface biomarkers in fresh tissues. Ex vivo and in vivo experiments were performed to optimize our strategy for the rapid detection of multiple cell-surface biomarkers following a brief (5 min) topical application of SERS NPs on tissues. The simultaneous detection and ratiometric quantification of targeted and nontargeted NPs allows for an unambiguous assessment of molecular expression that is insensitive to nonspecific variations in NP concentrations, potentially enabling point-of-care surgical guidance or early disease detection.

  4. Surface-Enhanced Raman Scattering (SERS) for Detection in Immunoassays. Applications, fundamentals, and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Driskell, Jeremy Daniel [Iowa State Univ., Ames, IA (United States)

    2006-08-09

    Immunoassays have been utilized for the detection of biological analytes for several decades. Many formats and detection strategies have been explored, each having unique advantages and disadvantages. More recently, surface-enhanced Raman scattering (SERS) has been introduced as a readout method for immunoassays, and has shown great potential to meet many key analytical figures of merit. This technology is in its infancy and this dissertation explores the diversity of this method as well as the mechanism responsible for surface enhancement. Approaches to reduce assay times are also investigated. Implementing the knowledge gained from these studies will lead to a more sensitive immunoassay requiring less time than its predecessors. This dissertation is organized into six sections. The first section includes a literature review of the previous work that led to this dissertation. A general overview of the different approaches to immunoassays is given, outlining the strengths and weaknesses of each. Included is a detailed review of binding kinetics, which is central for decreasing assay times. Next, the theoretical underpinnings of SERS is reviewed at its current level of understanding. Past work has argued that surface plasmon resonance (SPR) of the enhancing substrate influences the SERS signal; therefore, the SPR of the extrinsic Raman labels (ERLs) utilized in our SERS-based immunoassay is discussed. Four original research chapters follow the Introduction, each presented as separate manuscripts. Chapter 2 modifies a SERS-based immunoassay previously developed in our group, extending it to the low-level detection of viral pathogens and demonstrating its versatility in terms of analyte type, Chapter 3 investigates the influence of ERL size, material composition, and separation distance between the ERLs and capture substrate on the SERS signal. This chapter links SPR with SERS enhancement factors and is consistent with many of the results from theoretical treatments

  5. ACERCA DO TRATADO SOBRE O NÃO-SER DE GÓRGIAS

    OpenAIRE

    Cavalcante Brígido, Anúzia Gabrielle

    2015-01-01

    RESUMO Pretende-se aqui uma breve interpretação do Tratado sobre o não-ser, de Górgias, tentando expor qual a posição do autor a respeito da relação que existiria entre realidade/verdade, pensamento e discurso. Vemos nesse tratado uma forte crítica da identidade entre ser, pensar e dizer que é operada pela ontologia de Parmênides. Crítica essa elaborada a partir das consequências mais extremas do próprio Poema do eleata. Pensamos, portanto, que é a partir dos enunciados do texto parmenidiano ...

  6. Phosphoproteome analysis of E-coli reveals evolutionary conservation of bacterial Ser/Thr/Tyr phosphorylation

    DEFF Research Database (Denmark)

    Macek, B.; Gnad, F.; Soufi, Boumediene

    2008-01-01

    we use a recently developed proteomics approach based on phosphopeptide enrichment and high accuracy MS to analyze the phosphoproteome of the model Gram-negative bacterium Escherichia coli. We report 81 phosphorylation sites on 79 E. coli proteins, with distribution of Ser/Thr/Tyr phosphorylation...... sites 68%/23%/9%. Despite their phylogenetic distance, phosphoproteomes of E. coli and B. subtilis show striking similarity in size, classes of phosphorylated proteins, and distribution of Ser/Thr/Tyr phosphorylation sites. By combining the two datasets, we created the largest phosphorylation site...

  7. Being elderly with functional dependence and their family caregivers Ser anciano con incapacidad y sus cuidadores familiares Ser idoso com incapacidade e seus cuidadores familiares

    Directory of Open Access Journals (Sweden)

    Amanda Maria Souza de Oliveira

    2012-01-01

    Full Text Available OBJECTIVE: To identify the authors` point of discussion on the elderly with functional dependence, correlating it with the ontological time discussed in Heidegger. METHODS: This is a bibliographic, systematic and qualitative study. Data was collected in the Scientific Electronic Library Online database. A total of 123 studies were identified, 15 studies were included considering the inclusion criteria. RESULTS: Based on the semantic analysis of Bardin, the following categories of analysis were established: being caregiver for the elderly with functional dependence, being elderly with functional dependence, family dynamics. CONCLUSION: It was understood that factors related to the worldliness of these people as family relationships, support of formal and informal services, economic and social situation, among others, are part of the history of these people influencing their modes of being. Searching to understand these factors is important to promote the health of these people, thinking of the biological and existential care.OBJETIVO: Identificar el punto de discusión de los autores sobre el anciano con incapacidad funcional, correlacionando con el tiempo ontológico heideggeriano. MÉTODOS: Estudio de tipo bibliográfico, sistemático y cualitativo. Los datos fueron recolectados en el banco de datos del Scientific Electronic Library Online. De un total de 123 publicaciones identificadas, fueron seleccionados 15 estudios, de acuerdo a los criterios de inclusión adoptados. RESULTADOS: Con base en el análisis temático de Bardin, fueron constituídas las siguientes categorías de análisis: ser-cuidador del anciano con incapacidad, ser-anciano con incapacidad, dinámica familiar. CONCLUSIÓN: Se comprendió que los factores relacionados a a relación familiar, apoyo de los servicios formales e informales, situación económica, social, entre otras, forman parte de la historicidad de éstas influenciando su modo de ser. Es importante buscar la

  8. The effect of hOGG1 Ser326Cys polymorphism on cancer risk: evidence from a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Bingbing Wei

    Full Text Available BACKGROUND: Human oxoguanine glycosylase 1 (hOGG1 in base excision repair (BER pathway plays a vital role in DNA repair. Numerous epidemiological studies have evaluated the association between hOGG1 Ser326Cys polymorphism and the risk of cancer. However, the results of these studies on the association remain conflicting. To derive a more precise estimation of the association, we conducted a meta-analysis. METHODOLOGY/PRINCIPAL FINDINGS: A comprehensive search was conducted to identify the eligible studies of hOGG1 Ser326Cys polymorphism and cancer risk. We used odds ratios (ORs with 95% confidence intervals (CIs to assess the strength of the association. We found that the hOGG1 Ser326Cys polymorphism was significantly associated with overall cancer risk (Cys/Cys vs. Ser/Ser: OR = 1.19, 95%CI = 1.09-1.30, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.16, 95%CI = 1.08-1.26, P<0.001. Moreover, in subgroup analyses by cancer types, the stronger significant association between hOGG1 Ser326Cys polymorphism and lung cancer risk was found (Cys/Cys vs. Ser/Ser: OR = 1.29, 95%CI = 1.16-1.44, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.22, 95%CI = 1.12-1.33, P<0.001. The significant effects of hOGG1 Ser326Cys polymorphism on colorectal, breast, bladder, prostate, esophageal, and gastric cancer were not detected. In addition, in subgroup analyses by ethnicities, we found that the hOGG1 Ser326Cys polymorphism was associated with overall cancer risk in Asians (Cys/Cys vs. Ser/Ser: OR = 1.21, 95%CI = 1.10-1.33, P<0.001. CONCLUSIONS: This meta-analysis showed that hOGG1 326Cys allele might be a low-penetrant risk factor for lung cancer.

  9. Atmospheric oxidation and carbon contamination of silver and its effect on surface-enhanced Raman spectroscopy (SERS)

    Science.gov (United States)

    Matikainen, Antti; Nuutinen, Tarmo; Itkonen, Tommi; Heinilehto, Santtu; Puustinen, Jarkko; Hiltunen, Jussi; Lappalainen, Jyrki; Karioja, Pentti; Vahimaa, Pasi

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) is considered a highly promising technology for different analytical purposes. The applications of SERS are still quite limited due its relatively poor quantitative repeatability and the fact that SERS is very sensitive to oxidation, which is a challenge especially with silver based SERS substrates. Here, the link between these phenomena is investigated by exposing silver SERS substrates to ambient laboratory air. We show that SERS intensity decreases exponentially after the exposure, which consequently leads to an increasing standard deviation (σ) in intensity. Within a five-hour measurement window, the SERS intensity already drops by 60%, while σ triples from 7% to 21%. The SERS results are supplemented by elemental analysis, which shows that oxidation and atmospheric carbon contamination coincide with the rapid SERS intensity decrease. The results emphasize how sensitive SERS is towards atmospheric contamination and how it can also reduce the measurement repeatability - even if the substrates are exposed to air just for a very short period of time.

  10. SERS-active ZnO/Ag hybrid WGM microcavity for ultrasensitive dopamine detection

    Science.gov (United States)

    Lu, Junfeng; Xu, Chunxiang; Nan, Haiyan; Zhu, Qiuxiang; Qin, Feifei; Manohari, A. Gowri; Wei, Ming; Zhu, Zhu; Shi, Zengliang; Ni, Zhenhua

    2016-08-01

    Dopamine (DA) is a potential neuro modulator in the brain which influences a variety of motivated behaviors and plays a key role in life science. A hybrid ZnO/Ag microcavity based on Whispering Gallery Mode (WGM) effect has been developed for ultrasensitive detection of dopamine. Utilizing this effect of structural cavity mode, a Raman signal of R6G (5 × 10-3 M) detected by this designed surface-enhanced Raman spectroscopy (SERS)-active substrate was enhanced more than 10-fold compared with that of ZnO film/Ag substrate. Also, this hybrid microcavity substrate manifests high SERS sensitivity to rhodamine 6 G and detection limit as low as 10-12 M to DA. The Localized Surface Plasmons of Ag nanoparticles and WGM-enhanced light-matter interaction mainly contribute to the high SERS sensitivity and help to achieve a lower detection limit. This designed SERS-active substrate based on the WGM effect has the potential for detecting neurotransmitters in life science.

  11. Nonequilibrium Chemical Effects in Single-Molecule SERS Revealed by Ab Initio Molecular Dynamics Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Sean A.; Apra, Edoardo; Govind, Niranjan; Hess, Wayne P.; El-Khoury, Patrick Z.

    2017-02-03

    Recent developments in nanophotonics have paved the way for achieving significant advances in the realm of single molecule chemical detection, imaging, and dynamics. In particular, surface-enhanced Raman scattering (SERS) is a powerful analytical technique that is now routinely used to identify the chemical identity of single molecules. Understanding how nanoscale physical and chemical processes affect single molecule SERS spectra and selection rules is a challenging task, and is still actively debated. Herein, we explore underappreciated chemical phenomena in ultrasensitive SERS. We observe a fluctuating excited electronic state manifold, governed by the conformational dynamics of a molecule (4,4’-dimercaptostilbene, DMS) interacting with a metallic cluster (Ag20). This affects our simulated single molecule SERS spectra; the time trajectories of a molecule interacting with its unique local environment dictates the relative intensities of the observable Raman-active vibrational states. Ab initio molecular dynamics of a model Ag20-DMS system are used to illustrate both concepts in light of recent experimental results.

  12. Fabrication of SERS Active Surface on Polyimide Sample by Excimer Laser Irradiation

    Directory of Open Access Journals (Sweden)

    T. Csizmadia

    2014-01-01

    Full Text Available A possible application of excimer laser irradiation for the preparation of surface enhanced Raman spectroscopy (SERS substrate is demonstrated. A polyimide foil of 125 μm thickness was irradiated by 240 pulses of focused ArF excimer laser beam (λ = 193 nm, FWHM = 20 ns. The applied fluence was varied between 40 and 80 mJ/cm2. After laser processing, the sample was coated with 40 nm silver by PLD in order to create a conducting layer required for the SERS application. The SERS activity of the samples was tested by Raman microscopy. The Raman spectra of Rhodamine 6G aqueous solution (c=10−3 mol/dm3 were collected from the patterned and metalized areas. For areas prepared at 40–60 mJ/cm2 laser fluences, the measured Raman intensities have shown a linear dependence on the applied laser fluence, while above 60 mJ/cm2 saturation was observed. The morphology of the SERS active surface areas was investigated by scanning electron microscopy. Finite element modeling was performed in order to simulate the laser-absorption induced heating of the polyimide foil. The simulation resulted in the temporal and spatial distribution of the estimated temperature in the irradiated polyimide sample, which are important for understanding the structure formation process.

  13. ser & Twilight – for romantisk til at være gys?

    DEFF Research Database (Denmark)

    Schubart, Rikke

    2012-01-01

    Diskussion af ny antologi og hvorfor tøser elsker Twilight – bøgerne, filmene og fan-sites’ene på nettet – mens mænd nedgør fænomenet. Antologi: Interdiscipliary Approaches to Twilight: Studies in Fiction, Media, and a Contemporary Cultural Experience, redigeret af Mariah Larsson og Ann Steiner. ...

  14. Authoring Multiple "Formas de ser": Three Bilingual Latino/a Fifth Graders Navigating School

    Science.gov (United States)

    Cuero, Kimberley K.

    2009-01-01

    Drawing from sociocultural and anthropological perspectives, I present 3 case examples of bilingual, Mexican-origin students enrolled in a transitional bilingual educational program in an urban elementary school. By using the theoretical constructs of figured worlds, authoring, and "formas de ser" (ways of being), I examine how student identities…

  15. Plasmonic SERS nanochips and nanoprobes for medical diagnostics and bio-energy applications

    Science.gov (United States)

    Ngo, Hoan T.; Wang, Hsin-Neng; Crawford, Bridget M.; Fales, Andrew M.; Vo-Dinh, Tuan

    2017-02-01

    The development of rapid, easy-to-use, cost-effective, high accuracy, and high sensitive DNA detection methods for molecular diagnostics has been receiving increasing interest. Over the last five years, our laboratory has developed several chip-based DNA detection techniques including the molecular sentinel-on-chip (MSC), the multiplex MSC, and the inverse molecular sentinel-on-chip (iMS-on-Chip). In these techniques, plasmonic surface-enhanced Raman scattering (SERS) Nanowave chips were functionalized with DNA probes for single-step DNA detection. Sensing mechanisms were based on hybridization of target sequences and DNA probes, resulting in a distance change between SERS reporters and the Nanowave chip's gold surface. This distance change resulted in change in SERS intensity, thus indicating the presence and capture of the target sequences. Our techniques were single-step DNA detection techniques. Target sequences were detected by simple delivery of sample solutions onto DNA probe-functionalized Nanowave chips and SERS signals were measured after 1h - 2h incubation. Target sequence labeling or washing to remove unreacted components was not required, making the techniques simple, easy-to-use, and cost effective. The usefulness of the techniques for medical diagnostics was illustrated by the detection of genetic biomarkers for respiratory viral infection and of dengue virus 4 DNA.

  16. Detection of Water Binding to the Oxygen Evolving Complex Using Low Frequency Sers

    Science.gov (United States)

    Wilson, Andrew J.; Jain, Prashant

    2017-06-01

    The oxygen evolving complex (OEC) in Photosystem II (PSII) is a hallmark catalyst for efficiently splitting water to generate molecular oxygen. Much of what is known about the structure of the OEC has been provided by X-ray analysis of PSII at low temperatures, from which the mechanism of water splitting has been inferred. Surface-enhanced Raman scattering (SERS) offers an opportunity to build on our current understanding of this catalytic system as it can provide time-resolved, molecular vibrational information in a physiological environment. With low frequency SERS, we are able to separate the manganese oxide vibrational modes of the OEC from those in a complex, biological environment. With isotopically labelled water, we use SERS to identify water binding to the OEC. Raman spectra calculated by density functional theory support the assignment of water binding to a manganese atom outside of the cuboidal OEC. Detection of water binding sites on the OEC with SERS can not only compliment previous structural studies, but can also provide a powerful platform for in operando mechanistic studies.

  17. DNA self-assembly on graphene surface studied by SERS mapping

    DEFF Research Database (Denmark)

    Botti, Sabina; Rufoloni, Alessandro; Laurenzi, Susanna;

    2016-01-01

    The self-assembly of double-stranded DNA (dsDNA) segments on two variations of graphene surfaces having nano-platelets with different lateral sizes and thicknesses was investigated using surface enhanced Raman spectroscopy (SERS) and electrical impedance spectroscopy (EIS) techniques. Due to the ...

  18. Nanoembossed gold nanoshell with a fluorescence-like strong SERS signal

    Science.gov (United States)

    Kim, J. H.; Pompa, P. P.; Baek, H. G.; Chung, B. H.

    2016-04-01

    We present a nanoembossed nanoshell with a new internal location for the formation of strong electromagnetic fields. The internally nanoembossed gold nanoshell (AuNS) is fabricated by electrostatically assembling smaller silica nanoparticles (∼15.7 nm) around the silica core (∼123.6 nm) followed by growing gold nanoseeds on the core in a wet process. FDTD calculations reveal the creation of a strong electromagnetic field (|E/Ein|max = 55 at 633 nm) at sharp edges formed by the contact between the nanoembosses and the silica core. The field formation is supported by measuring the SERS signal of Ru(bpy) encapsulated in the nanoembossing silica nanoparticles. SERS signals as strong as the corresponding fluorescence are obtained. The Raman enhancement factor (EF) is estimated to be up to 1010 at 633 nm excitation, in addition to a comparable EF at 785 nm laser excitation. The SERS intensity of the nanoembossed nanoshell layer is sufficiently high compared to the outer or the core of the nanoshell. Finally, we fabricate all-in-one nanoparticles with all the three places where the reporter dyes are loaded and acquire the highest SERS intensity to potentially enable bio-medical applications of the nanoembossed AuNS as a sensitive and reliable labeling particle.

  19. Complete urinary tract infection (UTI) diagnosis and antibiogram using surface enhanced Raman spectroscopy (SERS)

    Science.gov (United States)

    Hadjigeorgiou, Katerina; Kastanos, Evdokia; Kyriakides, Alexandros; Pitris, Costas

    2012-03-01

    There are three stages to a complete UTI diagnosis: (1) identification of a urine sample as positive/negative for an infection, (2) identification of the responsible bacterium, (3) antibiogram to determine the antibiotic to which the bacteria are most sensitive to. Using conventional methods, all three stages require bacterial cultures in order to provide results. This long delay in diagnosis causes a rise in ineffective treatments, chronic infections, health care costs and antibiotic resistance. In this work, SERS is used to identify a sample as positive/negative for a UTI as well as to obtain an antibiogram against different antibiotics. SERS spectra of serial dilutions of E. coli bacteria mixed with silver nanoparticles, showed a linear correlation between spectral intensity and concentration. For antibiotic sensitivity testing, SERS spectra of three species of gram negative bacteria were collected four hours after exposure to the antibiotics ciprofloxacin and amoxicillin. Spectral analysis revealed clear separation between bacterial samples exposed to antibiotics to which they were sensitive and samples exposed to antibiotics to which they were resistant. With the enhancement provided by SERS, the technique can be applied directly to urine samples leading to the development of a new, rapid method for UTI diagnosis and antibiogram.

  20. O ser humano da sociedade capitalista na concepção de Erich Fromm

    Directory of Open Access Journals (Sweden)

    Edmilson Ferreira Marques

    2010-07-01

    Full Text Available

    A proposta deste texto é buscar na psicanálise pensada e desenvolvida por Erich Fromm elementos para se pensar o ser humano da sociedade capitalista. Erich Fromm, dentre a maioria dos psicanalistas existentes, desde Freud, procurou desenvolver suas pesquisas e reflexões a partir da “psicanálise humanista”, oferecendo, assim, recursos heurísticos fundamentais para se pensar a vida na sociedade. Nesse sentido, propomos analisar primeiramente o seu método de análise, a partir do qual acreditamos ser fundamental para compreender o procedimento teórico/metodológico que utilizava para pensar os temas por ele abordados, e, nesse sentido, encontrar o caminho a ser percorrido na busca em seu pensamento da seguinte questão: como abordar a partir de seu ponto de vista, o ser humano da sociedade capitalista? Enfim, propomos uma avaliação da própria teoria de Fromm, apontando suas principais contribuições.

  1. Disordered array of Au covered Silicon nanowires for SERS biosensing combined with electrochemical detection

    Science.gov (United States)

    Convertino, Annalisa; Mussi, Valentina; Maiolo, Luca

    2016-04-01

    We report on highly disordered array of Au coated silicon nanowires (Au/SiNWs) as surface enhanced Raman scattering (SERS) probe combined with electrochemical detection for biosensing applications. SiNWs, few microns long, were grown by plasma enhanced chemical vapor deposition on common microscope slides and covered by Au evaporated film, 150 nm thick. The capability of the resulting composite structure to act as SERS biosensor was studied via the biotin-avidin interaction: the Raman signal obtained from this structure allowed to follow each surface modification step as well as to detect efficiently avidin molecules over a broad range of concentrations from micromolar down to the nanomolar values. The metallic coverage wrapping SiNWs was exploited also to obtain a dual detection of the same bioanalyte by electrochemical impedance spectroscopy (EIS). Indeed, the SERS signal and impedance modifications induced by the biomolecule perturbations on the metalized surface of the NWs were monitored on the very same three-electrode device with the Au/SiNWs acting as both working electrode and SERS probe.

  2. A reusable biosensor chip for SERS-fluorescence dual mode immunoassay

    Science.gov (United States)

    Wu, Lei; Wang, Zhuyuan; Fan, Kequan; Zong, Shenfei; Cui, Yiping

    2015-05-01

    Research continues in an effort to develop a versatile platform for clinical diagnosis with easy operation and low cost. In the present study, a biosensor chip has been designed and fabricated for surface enhanced Raman scattering (SERS)- fluorescence dual mode immunoassay. Here, a dual channel microfluidic chip was employed for simultaneous SERS and fluorescence detection. Unlike previously reported microfluidic immunoassays using fluorescence or SERS method independently, the proposed dual mode biosensor combined the advantages of these two optical detection techniques. The fluorescence mode can be used for fast screening of biomolecules while the SERS mode can be employed for accurate and sensitive quantitative analysis. In addition, the chip-based microfluidic platform greatly reduced the reagents cost and complicated operation. The whole detection process from sample preparation to optical detection can be finished in 90 min. Moreover, the reversibly bonded biosensor chip could be reused after cleaning, which further reduced the cost for each assay. All these merits make it a potential powerful tool for practical clinical diagnosis.

  3. SERS and DFT study of p-hydroxybenzoic acid adsorbed on colloidal silver particles.

    Science.gov (United States)

    Chen, Y; Chen, S J; Li, S; Wei, J J

    2015-10-16

    In this study, normal Raman spectra of p—hydroxybenzoic acid (PHBA) powder and its surface—enhanced Raman scattering (SERS) spectra in silver colloidal solutions were measured under near infrared excitation conditions. In theoretical calculation, two models of PHBA adsorbed on the surfaces of silver nanoparticles were established. The Raman frequencies of these two models using density functional theory (DFT) method were calculated, and compared with the experimental results. It was found that the calculated Raman frequencies were in good agreement with experimental values, which indicates that there are two enhanced mechanism physical (electromagnetic, EM) enhancement and chemical (charge—transfer, CT) enhancement, in silver colloidal solutions regarding SERS effect. Furthermore, from high—quality SERS spectrum of PHBA obtained in silver colloids, we inferred that PHBA molecules in silver colloids adsorb onto the metal surfaces through carboxyl at a perpendicular orientation. The combination of SERS spectra and DFT calculation is thus useful for studies of the adsorption—orientation of a molecule on a metal colloid.

  4. Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase.

    Science.gov (United States)

    Liu, Tao; Tian, Chang Fu; Chen, Wen Xin

    2015-01-01

    Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion). These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

  5. Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase.

    Directory of Open Access Journals (Sweden)

    Tao Liu

    Full Text Available Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis, ActR (pH stress and microaerobic adaption, SupA (potassium stress, chaperonin GroEL2 (viability and potentially symbiosis, and ExoP (succinoglycan synthesis and secretion. These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

  6. A Deeper Look at the Grammar and Some Implications of "Ser" and "Estar" + Locative in Spanish.

    Science.gov (United States)

    Franco, Fabiola; Steinmetz, Donald

    1985-01-01

    Argues that the explanation of the use of "ser" and "estar" with locatives presented in the March 1984 issue of "Hispania" derives so directly from a theory of universal grammar because it is indicative of the explanatory adequacy of Case Grammar or of other, comparable theories of the deeper levels of linguistic structure. (SED)

  7. Gold-coated silver dendrites as SERS substrates with an improved lifetime.

    Science.gov (United States)

    Gutés, Albert; Maboudian, Roya; Carraro, Carlo

    2012-12-21

    Nanostructured silver is known to yield the highest signal-enhancement factors in surface-enhanced Raman spectroscopy, but its low chemical stability toward oxidation presents a challenge in the realization of Ag-based SERS substrates with long operating lifetimes. Here, a study of the long-term stability of silver dendrites as SERS substrates is reported. SERS spectra of 1,2-benzenedithiol monolayers on Ag dendrites, acquired over a period of time in excess of 1 year, shows appreciable degradation with time. However, no degradation is observed in the spectra of monolayers deposited on Ag dendrites that were coated with a monolayer-thin Au film deposited by an immersion plating process. X-ray photoelectron spectra confirm the oxidation of the uncoated Ag dendrites whereas no chemical changes are detected in the Au-coated ones. These results suggest that the galvanic displacement of Au on preformed Ag nanostructures provides a suitable route to producing SERS-active substrates with long operating and/or shelf lifetimes.

  8. O uso implícito das indicações formais em Ser e Tempo

    Directory of Open Access Journals (Sweden)

    Juliana Missaggia

    2012-06-01

    Full Text Available Nesse artigo é apresentado o uso do método indicativo-formal em Ser e Tempo. Embora Heidegger não desenvolva nessa obra nenhuma análise que trate especificamente das indicações formais, sua utilização nos parece clara – não somente pelo uso do termo “formale Anzeige” em diversas passagens, mas também pela própria estrutura dos argumentos. Procuramos demonstrar como a compreensão do uso implícito de tal metodologia é fundamental para a compreensão de Ser e Tempo. Primeiramente, é apresentado o caráter indicativo-formal do chamado “círculo hermenêutico”, o qual Heidegger analisa em vários trechos da obra, sempre em relação com seu aspecto metodológico. A seguir, procuramos exemplificar o uso das indicações formais em Ser e Tempo, através dos conceitos utilizados por Heidegger na exposição do modo de ser do Dasein. Tal análise é interessante não somente para confirmar a utilização do novo método na obra, mas também para esclarecer, com um exemplo concreto, como ocorre sua aplicação.

  9. Efectividad del láser de baja intensidad en el control de la hipersensibilidad dentrinaria

    OpenAIRE

    Gomez, Nadia; Garcia, Karen; HERRERA, Helen; Herrera, Henry

    2008-01-01

    La hipersensibilidad dentinaria se define "un dolor breve y agudo que se origina en la dentina expuesta como respuesta a los estímulos típicos como los térmicos, evaporativos, táctiles, osmóticos o químicos que no pueden ser atribuidos a otra patología dental

  10. Planar SERS nanostructures with stochastic silver ring morphology for biosensor chips

    DEFF Research Database (Denmark)

    Semenova, Anna; Goodilin, Eugene; Brazhe, Nadezda

    2012-01-01

    Surface-enhanced Raman spectroscopy (SERS) of living cells has rapidly become a powerful trend in biomedical diagnostics. It is a common belief that highly ordered, artificially engineered substrates are the best future decision in this field. This paper, however, describes an alternative success...... the substrates promising for various biosensor chips. Introduction...

  11. Towards quantitative SERS detection of hydrogen cyanide at ppb level for human breath analysis

    DEFF Research Database (Denmark)

    Lauridsen, Rikke Kragh; Rindzevicius, Tomas; Molin, Søren;

    2015-01-01

    ) at ppb level has been reported to be a PA biomarker. For early PA detection in CF children not yet chronically lung infected a non-invasive Surface-Enhanced Raman Spectroscopy (SERS)-based breath nanosensor is being developed. The triple bond between C and N in cyanide, with its characteristic band...

  12. Quantitative Analysis of Single and Mix Food Antiseptics Basing on SERS Spectra with PLSR Method

    Science.gov (United States)

    Hou, Mengjing; Huang, Yu; Ma, Lingwei; Zhang, Zhengjun

    2016-06-01

    Usage and dosage of food antiseptics are very concerned due to their decisive influence in food safety. Surface-enhanced Raman scattering (SERS) effect was employed in this research to realize trace potassium sorbate (PS) and sodium benzoate (SB) detection. HfO2 ultrathin film-coated Ag NR array was fabricated as SERS substrate. Protected by HfO2 film, the SERS substrate possesses good acid resistance, which enables it to be applicable in acidic environment where PS and SB work. Regression relationship between SERS spectra of 0.3~10 mg/L PS solution and their concentration was calibrated by partial least squares regression (PLSR) method, and the concentration prediction performance was quite satisfactory. Furthermore, mixture solution of PS and SB was also quantitatively analyzed by PLSR method. Spectrum data of characteristic peak sections corresponding to PS and SB was used to establish the regression models of these two solutes, respectively, and their concentrations were determined accurately despite their characteristic peak sections overlapping. It is possible that the unique modeling process of PLSR method prevented the overlapped Raman signal from reducing the model accuracy.

  13. Duplex microfluidic SERS detection of pathogen antigens with nanoyeast single-chain variable fragments.

    Science.gov (United States)

    Wang, Yuling; Rauf, Sakandar; Grewal, Yadveer S; Spadafora, Lauren J; Shiddiky, Muhammad J A; Cangelosi, Gerard A; Schlücker, Sebastian; Trau, Matt

    2014-10-07

    Quantitative and accurate detection of multiple biomarkers would allow for the rapid diagnosis and treatment of diseases induced by pathogens. Monoclonal antibodies are standard affinity reagents applied for biomarkers detection; however, their production is expensive and labor-intensive. Herein, we report on newly developed nanoyeast single-chain variable fragments (NYscFv) as an attractive alternative to monoclonal antibodies, which offers the unique advantage of a cost-effective production, stability in solution, and target-specificity. By combination of surface-enhanced Raman scattering (SERS) microspectroscopy using glass-coated, highly purified SERS nanoparticle clusters as labels, with a microfluidic device comprising multiple channels, a robust platform for the sensitive duplex detection of pathogen antigens has been developed. Highly sensitive detection for individual Entamoeba histolytica antigen EHI_115350 (limit of detection = 1 pg/mL, corresponding to 58.8 fM) and EHI_182030 (10 pg/mL, corresponding 453 fM) with high specificity has been achieved, employing the newly developed corresponding NYscFv as probe in combination with SERS microspectroscopy at a single laser excitation wavelength. Our first report on SERS-based immunoassays using the novel NYscFv affinity reagent demonstrates the flexibility of NYscFv fragments as viable alternatives to monoclonal antibodies in a range of bioassay platforms and paves the way for further applications.

  14. Danmark læser - en kulturkampagne mellem flere tider og mange dagsordner

    DEFF Research Database (Denmark)

    Dalsgård, Anne Line; Lund, Niels D.

    2016-01-01

    The national campaign Denmark is reading (Danmark læser) was carried out in the years 2013-15 and was a significant cultural policy initiative – the biggest of its kind ever in Denmark – with the object of getting more Danes to read fiction. This article describes the aim and contents of the camp...

  15. Metal Nanoparticles Deposited on Porous Silicon Templates as Novel Substrates for SERS

    Directory of Open Access Journals (Sweden)

    Lara Mikac

    2015-12-01

    Full Text Available In this paper, results on preparation of stable and uniform SERS solid substrates using macroporous silicon (pSi with deposited silver and gold are presented. Macroporous silicon is produced by anodisation of p-type silicon in hydrofluoric acid. The as prepared pSi is then used as a template for Ag and Au depositions. The noble metals were deposited in three different ways: by immersion in silver nitrate solution, by drop-casting silver colloidal solution and by pulsed laser ablation (PLA. Substrates obtained by different deposition processes were evaluated for SERS efficiency using methylene blue (MB and rhodamine 6G (R6G at 514.5, 633 and 785 nm. Using 514.5 nm excitation and R6G the limits of detection (LOD for macroporous Si samples with noble metal nanostructures obtained by immersion of pSi sample in silver nitrate solution and by applying silver colloidal solution to pSi template were 10–9 M and 10–8 M respectively. Using 633 nm laser and MB the most noticeable SERS activity gave pSi samples ablated with 30000 and 45000 laser pulses where the LODs of 10–10 M were obtained. The detection limit of 10–10 M was also reached for 4 mA cm–2-15 min pSi sample, silver ablated with 30000 pulses. Macroporous silicon proved to be a good base for the preparation of SERS substrates.

  16. Next-generation surface-enhanced Raman scattering (SERS) substrates for hazard detection

    Science.gov (United States)

    Farrell, Mikella E.; Holthoff, Ellen L.; Pellegrino, Paul M.

    2012-06-01

    Sensitive, accurate and reliable methods are needed for the detection and identification of hazardous materials (chemical, biological, and energetic) in the field. Utilizing such a sensing capability incorporated into a portable detection system would have wide spread beneficial impact to the U.S. military and first responder communities. Surface enhanced Raman scattering (SERS) is increasingly becoming a reputable technique for the real-time, dynamic detection and identification of hazard materials. SERS is particularly advantageous as it does not suffer from interferences from water, requires little to no sample preparation, is robust and can be used in numerous environments, is relatively insensitive to the wavelength of excitation employed, and produces a narrow-band spectral signature unique to the molecular vibrations of the analyte. We will report on the characterization and sensing capabilities of these next generation SERS substrates for the detection of energetic materials (ammonium nitrate, TNT, PETN, and RDX). Additionally, new efforts producing highly uniform samples, with known concentrations of energetic materials inkjet printed onto the SERS sensing surface using a precisely calibrated MicroJet system will be shown.

  17. Non-lithographic SERS substrates: tailoring surface chemistry for Au nanoparticle cluster assembly.

    Science.gov (United States)

    Adams, Sarah M; Campione, Salvatore; Caldwell, Joshua D; Bezares, Francisco J; Culbertson, James C; Capolino, Filippo; Ragan, Regina

    2012-07-23

    Near-field plasmonic coupling and local field enhancement in metal nanoarchitectures, such as arrangements of nanoparticle clusters, have application in many technologies from medical diagnostics, solar cells, to sensors. Although nanoparticle-based cluster assemblies have exhibited signal enhancements in surface-enhanced Raman scattering (SERS) sensors, it is challenging to achieve high reproducibility in SERS response using low-cost fabrication methods. Here an innovative method is developed for fabricating self-organized clusters of metal nanoparticles on diblock copolymer thin films as SERS-active structures. Monodisperse, colloidal gold nanoparticles are attached via a crosslinking reaction on self-organized chemically functionalized poly(methyl methacrylate) domains on polystyrene-block-poly(methyl methacrylate) templates. Thereby nanoparticle clusters with sub-10-nanometer interparticle spacing are achieved. Varying the molar concentration of functional chemical groups and crosslinking agent during the assembly process is found to affect the agglomeration of Au nanoparticles into clusters. Samples with a high surface coverage of nanoparticle cluster assemblies yield relative enhancement factors on the order of 10⁹ while simultaneously producing uniform signal enhancements in point-to-point measurements across each sample. High enhancement factors are associated with the narrow gap between nanoparticles assembled in clusters in full-wave electromagnetic simulations. Reusability for small-molecule detection is also demonstrated. Thus it is shown that the combination of high signal enhancement and reproducibility is achievable using a completely non-lithographic fabrication process, thereby producing SERS substrates having high performance at low cost.

  18. Efectividad del láser de baja intensidad en el control de la hipersensibilidad dentrinaria

    OpenAIRE

    2008-01-01

    La hipersensibilidad dentinaria se define "un dolor breve y agudo que se origina en la dentina expuesta como respuesta a los estímulos típicos como los térmicos, evaporativos, táctiles, osmóticos o químicos que no pueden ser atribuidos a otra patología dental

  19. Programmable SERS active substrates for chemical and biosensing applications using amorphous/crystalline hybrid silicon nanomaterial

    Science.gov (United States)

    Powell, Jeffery Alexander; Venkatakrishnan, Krishnan; Tan, Bo

    2016-01-01

    We present the creation of a unique nanostructured amorphous/crystalline hybrid silicon material that exhibits surface enhanced Raman scattering (SERS) activity. This nanomaterial is an interconnected network of amorphous/crystalline nanospheroids which form a nanoweb structure; to our knowledge this material has not been previously observed nor has it been applied for use as a SERS sensing material. This material is formed using a femtosecond synthesis technique which facilitates a laser plume ion condensation formation mechanism. By fine-tuning the laser plume temperature and ion interaction mechanisms within the plume, we are able to precisely program the relative proportion of crystalline Si to amorphous Si content in the nanospheroids as well as the size distribution of individual nanospheroids and the size of Raman hotspot nanogaps. With the use of Rhodamine 6G (R6G) and Crystal Violet (CV) chemical dyes, we have been able to observe a maximum enhancement factor of 5.38 × 106 and 3.72 × 106 respectively, for the hybrid nanomaterial compared to a bulk Si wafer substrate. With the creation of a silicon-based nanomaterial capable of SERS detection of analytes, this work demonstrates a redefinition of the role of nanostructured Si from an inactive to SERS active role in nano-Raman sensing applications.

  20. Towards quantitative SERS detection of hydrogen cyanide at ppb level for human breath analysis

    DEFF Research Database (Denmark)

    Lauridsen, Rikke Kragh; Rindzevicius, Tomas; Molin, Søren

    2015-01-01

    ) at ppb level has been reported to be a PA biomarker. For early PA detection in CF children not yet chronically lung infected a non-invasive Surface-Enhanced Raman Spectroscopy (SERS)-based breath nanosensor is being developed. The triple bond between C and N in cyanide, with its characteristic band...... at ∼2133 cm-1, is an excellent case for the SERS-based detection due to the infrequent occurrence of triple bonds in nature. For demonstration of direct HCN detection in the gas phase, a gold-coated silicon nanopillar substrate was exposed to 5 ppm HCN in N2. Results showed that HCN adsorbed on the SERS......). Lower KCN concentrations of 10 and 100 nM (corresponding to 0.18 and 1.8 ppb) produced SERS intensities that were relatively similar to the reference signal. Since HCN concentration in the breath of PA colonized CF children is reported to be ∼13.5 ppb, the detection of cyanide is within the required...

  1. Monitoring prion protein expression in complex biological samples by SERS for diagnostic applications

    Energy Technology Data Exchange (ETDEWEB)

    Manno, D; Filippo, E; Fiore, R; Serra, A [Dipartimento di Scienza dei Materiali, Universita del Salento, Lecce (Italy); Urso, E; Rizzello, A; Maffia, M [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Universita del Salento, Lecce (Italy)

    2010-04-23

    Surface-enhanced Raman spectroscopy (SERS) allows a new insight into the analysis of cell physiology. In this work, the difficulty of producing suitable substrates that, besides permitting the amplification of the Raman signal, do not interact with the biological material causing alteration, has been overcome by a combined method of hydrothermal green synthesis and thermal annealing. The SERS analysis of the cell membrane has been performed with special attention to the cellular prion protein PrP{sup C}. In addition, SERS has also been used to reveal the prion protein-Cu(II) interaction in four different cell models (B104, SH-SY5Y, GN11, HeLa), expressing PrP{sup C} at different levels. A significant implication of the current work consists of the intriguing possibility of revealing and quantifying prion protein expression in complex biological samples by a cheap SERS-based method, replacing the expensive and time-consuming immuno-assay systems commonly employed.

  2. Antibacterial effect of various shapes of silver nanoparticles monitored by SERS.

    Science.gov (United States)

    El-Zahry, Marwa R; Mahmoud, Amer; Refaat, Ibrahim H; Mohamed, Horria A; Bohlmann, Holger; Lendl, Bernhard

    2015-06-01

    A comparative evaluation of antimicrobial effect of synthesized silver nanoparticles (AgNPs) of different shapes using different methods was performed. Spherical, triangular and hexagonal AgNPs with an average size of 40 nm were chemically prepared and characterized by transmission electron microscope (TEM) and UV-visible spectroscopy. The antimicrobial effect of these different AgNPs against the gram negative bacterium Escherichia coli (E. coli) was studied by surface enhanced Raman spectroscopy (SERS), the evaluation of growth curves and inhibition zones. SERS proved to be sensitive to monitor the changes that occurred in the bacterial cells upon interaction with AgNPs, which qualitatively compared well with the data provided by the reference methods. However, as SERS is already sensitive to initial changes in the chemistry of bacteria due to the antibacterial effect of the AgNPs, fast and detailed information is provided by SERS as opposed to the classical reference methods based on the evaluation of growth curves and inhibition zones. The results of this work also demonstrate that hexagonal AgNPs display the highest antibacterial effect when compared to other NPs shapes, with triangular AgNPs exhibiting no antibacterial effect under the adopted conditions.

  3. Biological evaluation of Tyr6 and Ser7 modified drosocin analogues

    NARCIS (Netherlands)

    Visser, P.C. de; Hooft, P.A.V. van; Vries, A.-M. de; Jong, A. de; Marel, G.A. van der; Overkleeft, H.S.; Noort, D.

    2005-01-01

    An array of analogues of the cationic antimicrobial peptide drosocin was synthesized containing substitutions of Tyr6 and Ser7 in order to increase the proteolytic stability. Stabilizing the N-terminus with unnatural amino acids increased the serum stability of analogues by almost a factor 30 over a

  4. Raman and SERS recognition of β-carotene and haemoglobin fingerprints in human whole blood.

    Science.gov (United States)

    Casella, Michele; Lucotti, Andrea; Tommasini, Matteo; Bedoni, Marzia; Forvi, Elena; Gramatica, Furio; Zerbi, Giuseppe

    2011-09-01

    The present work reports on Raman and Surface Enhanced Raman Scattering (SERS) vibrational fingerprints of β-carotene and haemoglobin in fresh whole blood (i.e. right after blood test) with different laser excitations, i.e. visible (514 nm) and near-infrared (NIR, 785 nm). The use of colloidal silver nanoparticles significantly increases the Raman signal, thus providing a clear SERS spectrum of blood. The collected spectra have been examined and marker bands of β-carotene and of the haem prosthetic group of haemoglobin have been found. In particular, the fundamental features of β-carotene (514 nm excitation), blood proteins and haem molecules (785 nm excitation) were recognized and assigned. Moreover haemoglobin SERS signals can be identified and related with its oxygenation state (oxy-haemoglobin). The data reported show the prospects of Raman and SERS techniques to detect important bio-molecules in a whole blood sample with no pre-treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Catalytic Thr or Ser Residue Modulates Structural Switches in 2-Cys Peroxiredoxin by Distinct Mechanisms

    Science.gov (United States)

    Tairum, Carlos A.; Santos, Melina Cardoso; Breyer, Carlos A.; Geyer, R. Ryan; Nieves, Cecilia J.; Portillo-Ledesma, Stephanie; Ferrer-Sueta, Gerardo; Toledo, José Carlos; Toyama, Marcos H.; Augusto, Ohara; Netto, Luis E. S.; de Oliveira, Marcos A.

    2016-01-01

    Typical 2-Cys Peroxiredoxins (2-Cys Prxs) reduce hydroperoxides with extraordinary rates due to an active site composed of a catalytic triad, containing a peroxidatic cysteine (CP), an Arg, and a Thr (or Ser). 2-Cys Prx are involved in processes such as cancer; neurodegeneration and host-pathogen interactions. During catalysis, 2-Cys Prxs switch between decamers and dimers. Analysis of 2-Cys Prx structures in the fully folded (but not locally unfolded) form revealed a highly conserved, non-conventional hydrogen bond (CH-π) between the catalytic triad Thr of a dimer with an aromatic residue of an adjacent dimer. In contrast, structures of 2-Cys Prxs with a Ser in place of the Thr do not display this CH-π bond. Chromatographic and structural data indicate that the Thr (but not Ser) destabilizes the decamer structure in the oxidized state probably through steric hindrance. As a general trend, mutations in a yeast 2-Cys Prx (Tsa1) favoring the dimeric state also displayed a decreased catalytic activity. Remarkably, yeast naturally contains Thr-Ser variants (Tsa1 and Tsa2, respectively) with distinct oligomeric stabilities in their disulfide states. PMID:27629822

  6. Concepción de ser humano detrás de la Quinta Disciplina

    Directory of Open Access Journals (Sweden)

    Roldan Tomasz Suárez Litvin

    2010-01-01

    Full Text Available El presente ensayo expone el modo de ser de un ser humano promovido por la Quinta Disciplina de Peter Senge. Luego de un breve resumen de sus principales postulados, se destaca el modo como los mismos apuntan hacia una forma de humanidad y de relación entre el ámbito individual y el organizacional inconsistente con el esquema de pensamiento social moderno. Seguidamente se muestra que esta concepción no-moderna de ser humano guarda ciertas semejanzas con aquella propia de la cultura griega antigua, tal como ésta se expresa en el pensamiento aristotélico. En oposición a esta primera hipótesis interpretativa se procede a articular una segunda, basada en la reflexión heideggeriana acerca de la tecnología. Según esta segunda interpretación, la concepción sengiana de ser humano no constituye más que una muy poderosa reducción de los seres humanos a meros dispositivos al servicio de las organizaciones. Finalmente, se propone un posible camino de debate entre ambas hipótesis interpretativas.

  7. SERS-based multiple biomarker detection using a gold-patterned microarray chip

    Science.gov (United States)

    Kim, Insup; Junejo, Inam-ur-Rehman; Lee, Moonkwon; Lee, Sangyeop; Lee, Eun Kyu; Chang, Soo-Ik; Choo, Jaebum

    2012-09-01

    We report a highly sensitive surface-enhanced Raman scattering (SERS)-based immunoassay platform for the multiplex detection of biomarkers. For this purpose, a gold-patterned microarray chip has been fabricated and used as a SERS detection template. Here, a typical sandwich immunocomplex protocol was adopted. Monoclonal antibodies were immobilized on gold patterned substrates, and then antigen solutions and polyclonal antibody-conjugated hollow gold nanospheres (HGNs) were sequentially added for the formation of sandwich immunocomplexes. Antigen biomarkers can be quantitatively assayed by monitoring the intensity change of a characteristic SERS peak of a reporter molecule adsorbed on the surfaces of HGNs. Under optimized assay conditions, the limits of detections (LODs) were determined to be 10 fg/mL for human IgG and 10-100 fg/mL for rabbit IgG. In addition, the SERS-based immunoassay technique can be applied in a wider dynamic concentration range with a good sensitivity compared to ELISA. The proposed method fulfills the current needs of high sensitivity and selectivity which are essential for the clinical diagnosis of a disease.

  8. Baroja o la conciencia de que el novelista debe ser un artesano

    Directory of Open Access Journals (Sweden)

    Jaime Espinosa Dederle

    1979-04-01

    Full Text Available No se puede volver la mirada a la España romántica, sin detenernos con obstinada curiosidad en la novelística de Pío Baroja. Su obra, como en rigor toda gran obra literaria, sólo con la perspectiva del tiempo puede ser evaluada con alguna justeza y meditación.

  9. O efeito SERS na análise de traços: o papel das superfícies nanoestruturadas The SERS effect in trace analysis: the role of nanostructured surfaces

    Directory of Open Access Journals (Sweden)

    Antonio C. Sant'Ana

    2006-07-01

    Full Text Available Surface-Enhanced Raman Scattering - SERS - underwent huge advances since a single-molecule Raman spectrum was obtained in 1997. New theoretical and experimental approaches emerged since then leading to a better understanding of the enhancement mechanisms and to a significant improvement in the Raman signal. This review presents the current status of the SERS effect and the promising ways of designing and preparing high performance SERS-active substrates.

  10. PPARGC1A genotype (Gly482Ser) predicts exceptional endurance capacity in European men.

    Science.gov (United States)

    Lucia, Alejandro; Gómez-Gallego, Félix; Barroso, Inês; Rabadán, Manuel; Bandrés, Fernando; San Juan, Alejandro F; Chicharro, José L; Ekelund, Ulf; Brage, Soren; Earnest, Conrad P; Wareham, Nicholas J; Franks, Paul W

    2005-07-01

    Animal and human data indicate a role for the peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PPARGC1A) gene product in the development of maximal oxygen uptake (V(O2 max)), a determinant of endurance capacity, diabetes, and early death. We tested the hypothesis that the frequency of the minor Ser482 allele at the PPARGC1A locus is lower in World-class Spanish male endurance athletes (cases) [n = 104; mean (SD) age: 26.8 (3.8) yr] than in unfit United Kingdom (UK) Caucasian male controls [n = 100; mean (SD) age: 49.3 (8.1) yr]. In cases and controls, the Gly482Ser genotype met Hardy-Weinberg expectations (P > 0.05 in both groups tested separately). Cases had significantly higher V(O2 max) [73.4 (5.7) vs. 29.4 ml x kg(-1) x min(-1) (3.8); P < 0.0001] and were leaner [body mass index: 20.6 (1.5) vs. 27.6 kg/m2 (3.9); P < 0.0001] than controls. In unadjusted chi2 analyses, the frequency of the minor Ser482 allele was significantly lower in cases than in controls (29.1 vs. 40.0%; P = 0.01). To assess the possibility that genetic stratification could confound these observations, we also compared Gly482Ser genotype frequencies in Spanish (n = 164) and UK Caucasian men (n = 381) who were unselected for their level of fitness. In these analyses, Ser482 allele frequencies were very similar (36.9% in Spanish vs. 37.5% in UK Caucasians, P = 0.83), suggesting that confounding by genetic stratification is unlikely to explain the association between Gly482Ser genotype and endurance capacity. In summary, our data indicate a role for the Gly482Ser genotype in determining aerobic fitness. This finding has relevance from the perspective of physical performance, but it may also be informative for the targeted prevention of diseases associated with low fitness such as Type 2 diabetes.

  11. Tuning plasmonic and chemical enhancement for SERS detection on graphene-based Au hybrids

    Science.gov (United States)

    Liang, Xiu; Liang, Benliang; Pan, Zhenghui; Lang, Xiufeng; Zhang, Yuegang; Wang, Guangsheng; Yin, Penggang; Guo, Lin

    2015-11-01

    Various graphene-based Au nanocomposites have been developed as surface-enhanced Raman scattering (SERS) substrates recently. However, efficient use of SERS has been impeded by the difficulty of tuning SERS enhancement effects induced from chemical and plasmonic enhancement by different preparation methods of graphene. Herein, we developed graphene-based Au hybrids through physical sputtering gold NPs on monolayer graphene prepared by chemical vapor deposition (CVD) as a CVD-G/Au hybrid, as well as graphene oxide-gold (GO/Au) and reduced-graphene oxide (rGO/Au) hybrids prepared using the chemical in situ crystallization growth method. Plasmonic and chemical enhancements were tuned effectively by simple methods in these as-prepared graphene-based Au systems. SERS performances of CVD-G/Au, rGO/Au and GO/Au showed a gradually monotonic increasing tendency of enhancement factors (EFs) for adsorbed Rhodamine 6G (R6G) molecules, which show clear dependence on chemical bonds between graphene and Au, indicating that the chemical enhancement can be steadily controlled by chemical groups in a graphene-based Au hybrid system. Most notably, we demonstrate that the optimized GO/Au was able to detect biomolecules of adenine, which displayed high sensitivity with a detection limit of 10-7 M as well as good reproducibility and uniformity.Various graphene-based Au nanocomposites have been developed as surface-enhanced Raman scattering (SERS) substrates recently. However, efficient use of SERS has been impeded by the difficulty of tuning SERS enhancement effects induced from chemical and plasmonic enhancement by different preparation methods of graphene. Herein, we developed graphene-based Au hybrids through physical sputtering gold NPs on monolayer graphene prepared by chemical vapor deposition (CVD) as a CVD-G/Au hybrid, as well as graphene oxide-gold (GO/Au) and reduced-graphene oxide (rGO/Au) hybrids prepared using the chemical in situ crystallization growth method. Plasmonic

  12. Informational redundancy of tRNA(4Ser) and tRNA(7Ser) genes in Drosophila melanogaster and evidence for intergenic recombination.

    Science.gov (United States)

    Leung, J; Sinclair, D A; Hayashi, S; Tener, G M; Grigliatti, T A

    1991-05-20

    Variant tRNA genes have been widely observed in multicellular eukaryotes. Recent biochemical studies have shown that some of them are expressed in a tissue- or a stage-specific manner. These findings would thus imply that certain modified tRNAs may be crucial for the development of the organism. Using Drosophila melanogaster as a model, we have taken a combined genetic and molecular approach to examine critically the possible biological functions of tRNA(4, 7Ser) genes. We showed that at least 50% of the total templates can be deleted from the genome without inducing abnormal phenotypes such as Minute, or a decrease in viability. In addition, two of the tRNASer variant genes that are unique in sequence are also completely dispensable. This strongly implies that even though they may be expressed in vivo, they play no essential role in the development of the fruitfly. By comparison with some of the corresponding tRNA genes in another sibling species, Drosophila erecta, our results suggest strongly that the variants are products non-reciprocal exchanges among the tRNA(4, 7Ser), genes. Such intergenic recombination events may have a major influence in the concerted evolution of the two gene families.

  13. Dependence of SERS enhancement on the chemical composition and structure of Ag/Au hybrid nanoparticles.

    Science.gov (United States)

    Chaffin, Elise; O'Connor, Ryan T; Barr, James; Huang, Xiaohua; Wang, Yongmei

    2016-08-01

    Noble metal nanoparticles (NPs) such as silver (Ag) and gold (Au) have unique plasmonic properties that give rise to surface enhanced Raman scattering (SERS). Generally, Ag NPs have much stronger plasmonic properties and, hence, provide stronger SERS signals than Au NPs. However, Ag NPs lack the chemical stability and biocompatibility of comparable Au NPs and typically exhibit the most intense plasmonic resonance at wavelengths much shorter than the optimal spectral region for many biomedical applications. To overcome these issues, various experimental efforts have been devoted to the synthesis of Ag/Au hybrid NPs for the purpose of SERS detections. However, a complete understanding on how the SERS enhancement depends on the chemical composition and structure of these nanoparticles has not been achieved. In this study, Mie theory and the discrete dipole approximation have been used to calculate the plasmonic spectra and near-field electromagnetic enhancements of Ag/Au hybrid NPs. In particular, we discuss how the electromagnetic enhancement depends on the mole fraction of Au in Ag/Au alloy NPs and how one may use extinction spectra to distinguish between Ag/Au alloyed NPs and Ag-Au core-shell NPs. We also show that for incident laser wavelengths between ∼410 nm and 520 nm, Ag/Au alloyed NPs provide better electromagnetic enhancement than pure Ag, pure Au, or Ag-Au core-shell structured NPs. Finally, we show that silica-core Ag/Au alloy shelled NPs provide even better performance than pure Ag/Au alloy or pure solid Ag and pure solid Au NPs. The theoretical results presented will be beneficial to the experimental efforts in optimizing the design of Ag/Au hybrid NPs for SERS-based detection methods.

  14. Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

    Directory of Open Access Journals (Sweden)

    Martina Banchelli

    2016-01-01

    Full Text Available Hybrid graphene oxide/silver nanocubes (GO/AgNCs arrays for surface-enhanced Raman spectroscopy (SERS applications were prepared by means of two procedures differing for the method used in the assembly of the silver nanocubes onto the surface: Langmuir–Blodgett (LB transfer and direct sequential physisorption of silver nanocubes (AgNCs. Adsorption of graphene oxide (GO flakes on the AgNC assemblies obtained with both procedures was monitored by quartz crystal microbalance (QCM technique as a function of GO bulk concentration. The experiment provided values of the adsorbed GO mass on the AgNC array and the GO saturation limit as well as the thickness and the viscoelastic properties of the GO film. Atomic force microscopy (AFM measurements of the resulting samples revealed that a similar surface coverage was achieved with both procedures but with a different distribution of silver nanoparticles. In the GO covered LB film, the AgNC distribution is characterized by densely packed regions alternating with empty surface areas. On the other hand, AgNCs are more homogeneously dispersed over the entire sensor surface when the nanocubes spontaneously adsorb from solution. In this case, the assembly results in less-packed silver nanostructures with higher inter-cube distance. For the two assembled substrates, AFM of silver nanocubes layers fully covered with GO revealed the presence of a homogeneous, flexible and smooth GO sheet folding over the silver nanocubes and extending onto the bare surface. Preliminary SERS experiments on adenine showed a higher SERS enhancement factor for GO on Langmuir–Blodgett films of AgNCs with respect to bare AgNC systems. Conversely, poor SERS enhancement for adenine resulted for GO-covered AgNCs obtained by spontaneous adsorption. This indicated that the assembly and packing of AgNCs obtained in this way, although more homogeneous over the substrate surface, is not as effective for SERS analysis.

  15. Noninvasive MRI-SERS Imaging in Living Mice Using an Innately Bimodal Nanomaterial

    Science.gov (United States)

    Yigit, Mehmet V.; Zhu, Leyun; Ifediba, Marytheresa A.; Zhang, Yong; Carr, Kevin; Moore, Anna; Medarova, Zdravka

    2011-01-01

    We report a novel nanomaterial (AuMN-DTTC) that can be used as a bimodal contrast agent for in vivo magnetic resonance imaging (MRI) and Raman spectroscopy. The probe consists of MRI-active superparamagnetic iron oxide nanoparticles, stably complexed with gold nanostructures. The gold component serves as a substrate for a Raman active dye molecule to generate a surface-enhanced Raman scattering (SERS) effect. The synthesized probe produces T2 weighted contrast and can be used as a SERS active material both in silico (in aqueous solution) and in vivo. A quantitative assessment of T2 relaxation times was obtained using multiecho MRI analysis. The T2 relaxation times of AuMN-DTTC and MN (dextran-coated iron oxide nanoparticles) were 29.23 + 1.45, and 31.58 + 1.7 msec, respectively. The SERS signature of AuMN-DTTC revealed peaks at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm−1. Intramuscular administration of the probe resulted in a decrease of the T2 relaxation time of muscle from 33.4 + 2.5 msec to 20.3 + 2.2. SERS peaks were observed at 508, 629, 782, 844, 1080, 1108, 1135, and 1242 cm−1, consistent with the in silico results. Our studies illustrate for the first time the design and in vivo application of a contrast agent, whose component modalities include MRI and SERS. The value of this agent lies in its innately bimodal nature and its application in vivo for molecular imaging applications. PMID:21194236

  16. Pseudomonas aeruginosa serA Gene Is Required for Bacterial Translocation through Caco-2 Cell Monolayers

    Science.gov (United States)

    Yasuda, Masashi; Nagata, Syouya; Yamane, Satoshi; Kunikata, Chinami; Kida, Yutaka; Kuwano, Koichi; Suezawa, Chigusa; Okuda, Jun

    2017-01-01

    To specify critical factors responsible for Pseudomonas aeruginosa penetration through the Caco-2 cell epithelial barrier, we analyzed transposon insertion mutants that demonstrated a dramatic reduction in penetration activity relative to P. aeruginosa PAO1 strain. From these strains, mutations could be grouped into five classes, specifically flagellin-associated genes, pili-associated genes, heat-shock protein genes, genes related to the glycolytic pathway, and biosynthesis-related genes. Of these mutants, we here focused on the serA mutant, as the association between this gene and penetration activity is yet unknown. Inactivation of the serA gene caused significant repression of bacterial penetration through Caco-2 cell monolayers with decreased swimming and swarming motilities, bacterial adherence, and fly mortality rate, as well as repression of ExoS secretion; however, twitching motility was not affected. Furthermore, L-serine, which is known to inhibit the D-3-phosphoglycerate dehydrogenase activity of the SerA protein, caused significant reductions in penetration through Caco-2 cell monolayers, swarming and swimming motilities, bacterial adherence to Caco-2 cells, and virulence in flies in the wild-type P. aeruginosa PAO1 strain. Together, these results suggest that serA is associated with bacterial motility and adherence, which are mediated by flagella that play a key role in the penetration of P. aeruginosa through Caco-2 cell monolayers. Oral administration of L-serine to compromised hosts might have the potential to interfere with bacterial translocation and prevent septicemia caused by P. aeruginosa through inhibition of serA function. PMID:28046014

  17. Fe65 Is Phosphorylated on Ser289 after UV-Induced DNA Damage.

    Directory of Open Access Journals (Sweden)

    Hannah Langlands

    Full Text Available Fe65 undergoes a phosphatase-sensitive gel mobility shift after DNA damage, consistent with protein phosphorylation. A recent study identified Ser228 as a specific site of phosphorylation, targeted by the ATM and ATR protein kinases, with phosphorylation inhibiting the Fe65-dependent transcriptional activity of the amyloid precursor protein (APP. The direct binding of Fe65 to APP not only regulates target gene expression, but also contributes to secretase-mediated processing of APP, producing cytoactive proteolytic fragments including the APP intracellular domain (AICD and cytotoxic amyloid β (Aβ peptides. Given that the accumulation of Aβ peptides in neural plaques is a pathological feature of Alzheimer's disease (AD, it is essential to understand the mechanisms controlling Aβ production. This will aid in the development of potential therapeutic agents that act to limit the deleterious production of Aβ peptides. The Fe65-APP complex has transcriptional activity and the complex is regulated by multiple post-translational modifications and other protein binding partners. In the present study, we have identified Ser289 as a novel site of UV-induced phosphorylation. Interestingly, this phosphorylation was mediated by ATM, rather than ATR, and occurred independently of APP. Neither phosphorylation nor mutation of Ser289 affected the Fe65-APP interaction, though this was markedly decreased after UV treatment, with a concomitant decrease in the protein levels of APP in cells. Using mutagenesis, we demonstrated that Fe65 Ser289 phosphorylation did not affect the transcriptional activity of the Fe65-APP complex, in contrast to the previously described Ser228 site.

  18. Surface enhanced Raman scattering (SERS) with biopolymer encapsulated silver nanosubstrates for rapid detection of foodborne pathogens.

    Science.gov (United States)

    Sundaram, Jaya; Park, Bosoon; Kwon, Yongkuk; Lawrence, Kurt C

    2013-10-01

    A biopolymer encapsulated with silver nanoparticles was prepared using silver nitrate, polyvinyl alcohol (PVA) solution, and trisodium citrate. It was deposited on a mica sheet to use as SERS substrate. Fresh cultures of Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus and Listeria innocua were washed from chicken rinse and suspended in 10 ml of sterile deionized water. Approximately 5 μl of the bacterial suspensions was placed on the substrate individually and exposed to 785 nm HeNe laser excitation. SERS spectral data were recorded over the Raman shift between 400 and 1800 cm(-1) from 15 different spots on the substrate for each sample; and three replicates were done on each bacteria type. Principal component analysis (PCA) model was developed to classify foodborne bacteria types. PC1 identified 96% of the variation among the given bacteria specimen, and PC2 identified 3%, resulted in a total of 99% classification accuracy. Soft Independent Modeling of Class Analogies (SIMCA) of validation set gave an overall correct classification of 97%. Comparison of the SERS spectra of different types of gram-negative and gram-positive bacteria indicated that all of them have similar cell walls and cell membrane structures. Conversely, major differences were noted around the nucleic acid and amino acid structure information between 1200 cm(-1) and 1700 cm(-1) and at the finger print region between 400 cm(-1) and 700 cm(-1). Silver biopolymer nanoparticle substrate could be a promising SERS tool for pathogen detection. Also this study indicates that SERS technology could be used for reliable and rapid detection and classification of food borne pathogens. Published by Elsevier B.V.

  19. Label-free direct surface-enhanced Raman scattering (SERS) of nucleic acids (Conference Presentation)

    Science.gov (United States)

    Guerrini, Luca; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Xie, Hainan; Alvarez-Puebla, Ramon

    2016-03-01

    Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity. To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.

  20. Highly sensitive SERS analysis of the cyclic Arg-Gly-Asp peptide ligands of cells using nanogap antennas.

    Science.gov (United States)

    Portela, Alejandro; Yano, Taka-Aki; Santschi, Christian; Martin, Olivier J F; Tabata, Hitoshi; Hara, Masahiko

    2017-02-01

    The cyclic RGD (cRGD) peptide ligands of cells have become widely used for treating several cancers. We report a highly sensitive analysis of c(RGDfC) using surface enhanced Raman spectroscopy (SERS) using single dimer nanogap antennas in aqueous environment. Good agreement between characteristic peaks of the SERS and the Raman spectra of bulk c(RGDfC) with its peptide's constituents were observed. The exhibited blinking of the SERS spectra and synchronization of intensity fluctuations, suggest that the SERS spectra acquired from single dimer nanogap antennas was dominated by the spectrum of single to a few molecules. SERS spectra of c(RGDfC) could be used to detect at the nanoscale, the cells' transmembrane proteins binding to its ligand. SERS of cyclic RGD on nanogap antenna.

  1. Association of OGG1 Ser326Cys polymorphism and pancreatic cancer susceptibility: evidence from a meta-analysis.

    Science.gov (United States)

    Yan, Yulan; Chen, Xu; Li, Taijie; Li, Meng; Liang, Hongjie

    2014-03-01

    The 8-oxoguanine DNA glycosylase (OGG1) gene has been considered to be associated with cancer susceptibility. The OGG1 Ser326Cys polymorphism has been reported to be associated with pancreatic cancer (PC), but the published studies have yielded inconsistent results. For better understanding of the effect of OGG1 Ser326Cys polymorphism on PC susceptibility, a meta-analysis was performed. All eligible studies were identified through a search of PubMed, Excerpta Medica Database (Embase), Elsevier Science Direct, and Chinese Biomedical Literature Database before May 2013. The association between the OGG1 Ser326Cys polymorphism and PC risk was conducted by odds ratios (ORs) and 95% confidence intervals (CIs). A total of five case-control studies with 1,690 cases and 3,650 controls were eventually collected. Overall, we found that OGG1 Ser326Cys polymorphism was not associated with PC susceptibility (Cys/Cys vs. Ser/Ser: OR = 0.95, 95% CI = 0.80-1.14; Cys/Cys vs. Ser/Ser + Ser/Cys: OR = 0.95, 95% CI = 0.78-1.14; Cys/Cys + Ser/Cys vs. Ser/Ser (OR = 1.00, 95% CI = 0.89-1.12)). In the subgroup analysis based on ethnicity, source of control, sample size, and genotyping method, no significant association was found in any genetic models. This meta-analysis suggests that the OGG1 Ser326Cys polymorphism may not associated with PC susceptibility. Considering the limited sample size and ethnicity included in the meta-analysis, further larger scaled and well-designed studies are needed to confirm our results.

  2. Galvanic-cell-induced growth of Ag nanosheet-assembled structures as sensitive and reproducible SERS substrates.

    Science.gov (United States)

    Li, Zhongbo; Meng, Guowen; Huang, Qing; Zhu, Chuhong; Zhang, Zhuo; Li, Xiangdong

    2012-11-19

    SERS up: Ag nanosheet-assembled structures with controlled morphologies were achieved on indium tin oxide substrates by galvanic-cell-induced growth (see figure). These structures exhibit a highly active and homogeneous surface-enhanced Raman scattering (SERS) effect, and show promising potential as reliable SERS substrates for detection of trace polychlorinated biphenyls. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Application of a SERS-based lateral flow immunoassay strip for the rapid and sensitive detection of staphylococcal enterotoxin B

    Science.gov (United States)

    Hwang, Joonki; Lee, Sangyeop; Choo, Jaebum

    2016-06-01

    A novel surface-enhanced Raman scattering (SERS)-based lateral flow immunoassay (LFA) biosensor was developed to resolve problems associated with conventional LFA strips (e.g., limits in quantitative analysis and low sensitivity). In our SERS-based biosensor, Raman reporter-labeled hollow gold nanospheres (HGNs) were used as SERS detection probes instead of gold nanoparticles. With the proposed SERS-based LFA strip, the presence of a target antigen can be identified through a colour change in the test zone. Furthermore, highly sensitive quantitative evaluation is possible by measuring SERS signals from the test zone. To verify the feasibility of the SERS-based LFA strip platform, an immunoassay of staphylococcal enterotoxin B (SEB) was performed as a model reaction. The limit of detection (LOD) for SEB, as determined with the SERS-based LFA strip, was estimated to be 0.001 ng mL-1. This value is approximately three orders of magnitude more sensitive than that achieved with the corresponding ELISA-based method. The proposed SERS-based LFA strip sensor shows significant potential for the rapid and sensitive detection of target markers in a simplified manner.A novel surface-enhanced Raman scattering (SERS)-based lateral flow immunoassay (LFA) biosensor was developed to resolve problems associated with conventional LFA strips (e.g., limits in quantitative analysis and low sensitivity). In our SERS-based biosensor, Raman reporter-labeled hollow gold nanospheres (HGNs) were used as SERS detection probes instead of gold nanoparticles. With the proposed SERS-based LFA strip, the presence of a target antigen can be identified through a colour change in the test zone. Furthermore, highly sensitive quantitative evaluation is possible by measuring SERS signals from the test zone. To verify the feasibility of the SERS-based LFA strip platform, an immunoassay of staphylococcal enterotoxin B (SEB) was performed as a model reaction. The limit of detection (LOD) for SEB, as

  4. Assessment of SERS activity and enhancement factors for highly sensitive gold coated substrates probed with explosive molecules

    Science.gov (United States)

    Botti, Sabina; Cantarini, Luciano; Almaviva, Salvatore; Puiu, Adriana; Rufoloni, Alessandro

    2014-01-01

    The surface enhanced Raman spectroscopy (SERS) is one of the most sensitive tools for trace analysis and the fabrication of effective and robust SERS substrates is the subject of intensive research in view of their possible applications. In this Letter, the SERS activity of an ordered structure of inverted pyramids (Klarite, Ltd) was examined by using nitro-based explosives, as Raman probe molecules. Enhancement factors up to 106 and detection limits of tens of pg were measured with an excellent run to run reproducibility. These findings provide new opportunities for the utilization of SERS for analytical detection at trace level.

  5. Determination of resonance Raman cross-sections for use in biological SERS sensing with femtosecond stimulated Raman spectroscopy.

    Science.gov (United States)

    Silva, W Ruchira; Keller, Emily L; Frontiera, Renee R

    2014-08-05

    Surface-enhanced Raman spectroscopy (SERS) is a promising technique for in vivo bioanalyte detection, but accurate characterization of SERS biosensors can be challenging due to difficulties in differentiating resonance and surface enhancement contributions to the Raman signal. Here, we quantitate the resonance Raman cross-sections for a commonly used near-infrared SERS dye, 3,3'-diethylthiatricarbocyanine (DTTC). It is typically challenging to measure resonance Raman cross-sections for fluorescent dye molecules due to the overwhelming isoenergetic fluorescence signal. To overcome this issue, we used etalon-based femtosecond stimulated Raman spectroscopy, which is intrinsically designed to acquire a stimulated Raman signal without strong fluorescence or interference from signals resulting from other four-wave mixing pathways. Using this technique, we found that the cross-sections for most of the resonantly enhanced modes in DTTC exceed 10(-25) cm(2)/molecule. These cross-sections lead to high signal magnitude SERS signals from even weakly enhancing SERS substrates, as much of what appears to be a SERS signal is actually coming from the intrinsically strong resonance Raman signal. Our work will lead to a more accurate determination of SERS enhancement factors and SERS substrate characterization in the biologically relevant near-infrared region, ultimately leading to a more widespread use of SERS for biosensing and bioimaging applications.

  6. Detection and analysis of SERS effect of nano gold by self-assembly chemical plating composite method

    Science.gov (United States)

    Wang, Chunyan; Xu, Yi; Zhao, Huazhou; Gang, Chen; Lai, Chunhong; Liao, Xin; Wang, Rong

    2015-10-01

    Surface-enhanced Raman spectroscopy (SERS) as a powerful analytical tool has gained extensive attention. Despite of many efforts have been devoted to design SERS substrates, it still remains a grand challenge for creating a general substrate with high SERS active by a simple, controllable and low-cost way. Herein, we attempt to address this issue by fabricating SERS-active nano gold film based on self-assembly chemical plating composite method. The influence of gold colloid particle size on gold seed distribution density and the influence of the particle size of nano gold films on the SERS activity were investigated in detail. 10-5 M Rhodamine 6G (R6G) was taken as Raman probe molecules and homemade Raman detection microsystem was used as detector. According to the results of SERS detection, the SERS substrate enhancement factors (SSEF) were calculated, and the nano gold film with average particle size of about 55 nm showed the maximum SSEF of 0.93 × 105, which indicated such nano gold films showed excellent SERS activity. Moreover, these nano gold films are all low-cost and easy to prepared. This study provided theoretical and experimental basis for the design and preparation of general SERS substrate.

  7. The BARD1 Cys557Ser variant and breast cancer risk in Iceland.

    Directory of Open Access Journals (Sweden)

    Simon N Stacey

    2006-07-01

    Full Text Available Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer.The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11-3.01, p = 0.014. The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22-4.75, p = 0.015. Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16-8.40, p = 0.046 in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We found that an excess of ancestors

  8. The BARD1 Cys557Ser variant and breast cancer risk in Iceland.

    Science.gov (United States)

    Stacey, Simon N; Sulem, Patrick; Johannsson, Oskar T; Helgason, Agnar; Gudmundsson, Julius; Kostic, Jelena P; Kristjansson, Kristleifur; Jonsdottir, Thora; Sigurdsson, Helgi; Hrafnkelsson, Jon; Johannsson, Jakob; Sveinsson, Thorarinn; Myrdal, Gardar; Grimsson, Hlynur Niels; Bergthorsson, Jon T; Amundadottir, Laufey T; Gulcher, Jeffrey R; Thorsteinsdottir, Unnur; Kong, Augustine; Stefansson, Kari

    2006-07-01

    Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer. The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11-3.01, p = 0.014). The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22-4.75, p = 0.015). Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16-8.40, p = 0.046) in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We found that an excess of ancestors of contemporary

  9. The BARD1 Cys557Ser variant and breast cancer risk in Iceland.

    Directory of Open Access Journals (Sweden)

    Simon N Stacey

    2006-07-01

    Full Text Available BACKGROUND: Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer. METHODS AND FINDINGS: The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11-3.01, p = 0.014. The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22-4.75, p = 0.015. Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16-8.40, p = 0.046 in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We

  10. Nanomolar detection of glucose using SERS substrates fabricated with albumin coated gold nanoparticles

    Science.gov (United States)

    Perez-Mayen, Leonardo; Oliva, Jorge; Salas, P.; de La Rosa, Elder

    2016-06-01

    This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles synthesized by a wet chemical method. The SERS substrates were used for glucose detection for concentrations as low as 10-7 M, which represents an enhancement factor (EF) of 109, as a result of the hot spot formed by the spike termination and appropriate distribution of the gold nanoparticles. An improvement of two orders of magnitude was obtained by coating the gold nanoparticles with albumin with the configuration: glass/Au nanoparticles/albumin. In this case the lowest detection was at a concentration of 10-9 M for an EF of 1011. The albumin molecule allowed us to enhance the Raman signal because of the formation of peptide bonds (COOH-NH2) generated due to the interaction of glucose with albumin, and the appropriate separation distance between the glucose molecules and gold nanoparticles. The presence of such peptide conjugates was confirmed by FTIR spectra. Thus, our results suggest that our SERS substrates can be useful for the detection of very low concentrations of glucose, which is important for the diagnosis of diabetes in the field of medicine.This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles synthesized by a wet chemical method. The SERS substrates were used for glucose detection for concentrations as low as 10-7 M, which represents an enhancement factor (EF) of 109, as a result of the hot spot formed by the spike termination and appropriate distribution of the gold nanoparticles. An improvement of two orders of magnitude was obtained by coating the gold nanoparticles with albumin with the configuration: glass/Au nanoparticles/albumin. In this case the lowest detection was at a concentration of 10-9 M for an EF of 1011. The albumin molecule allowed us to enhance the Raman signal because of the formation of peptide bonds (COOH-NH2) generated due to the

  11. Conformational preferences and prolyl cis-trans isomerization of phosphorylated Ser/Thr-Pro motifs.

    Science.gov (United States)

    Byun, Byung Jin; Kang, Young Kee

    2010-04-01

    The conformational study on Ac-pSer-Pro-NHMe and Ac-pThr-Pro-NHMe peptides has been carried out using hybrid density functional methods with the implicit solvation reaction field theory at the B3LYP/ 6-311++G(d,p)//B3LYP/6-31+G(d) level of theory in the gas phase and in solution (chloroform and water). For both pSer-Pro and pThr-Pro peptides in the gas phase and in chloroform, the most preferred conformation has the alpha-helical structure for the pSer/pThr residue, the down-puckered polyproline I structure for the Pro residue, and the cis prolyl peptide bond between the two residues, in which two hydrogen bonds between the phosphate oxygens with the backbone N--H groups seem to play a role. However, the trans conformations that have a single hydrogen bond of the phosphate oxygen with either of two backbone N--H groups become most preferred for both peptides in water. This is because the hydration free energy of the anionic oxygen of the phosphate group is expected to dramatically decrease for the cis conformation upon formation of the hydrogen bond with the backbone N--H groups. These calculated results are consistent with the observations by NMR and IR experiments, suggesting the existence of hydrogen bonds between the charged phosphoryl group and the backbone amide protons in solution. The calculated cis populations of 14.7 and 14.2% and rotational barriers of 19.87 and 20.57 kcal/mol to the cis-to-trans isomerization for pSer-Pro and pThr-Pro peptides in water, respectively, are consistent with the observed values for pSer-Pro and pThr-Pro containing peptides from NMR experiments. However, the hydrogen bond between the prolyl nitrogen and the following amide N--H group, which was suggested to be capable of catalyzing the prolyl isomerization, does not play a role in stabilizing the preferred transition state for the pSer/pThr-Pro peptides in water. Instead, the amide hydrogen of the NHMe group is involved in a bifurcated hydrogen bond with the anionic oxygen

  12. Background information for the SER Energy Agreement for Sustainable Growth calculations. Sector Built Environment; Achtergronddocument bij doorrekening SER Energieakkoord. Sector Gebouwde omgeving

    Energy Technology Data Exchange (ETDEWEB)

    Menkveld, M.; Tigchelaar, C. [ECN Beleidsstudies, Petten (Netherlands)

    2013-09-01

    This publication is part of the support given by ECN and PBL in the development of a national energy agreement between March and September 2013 as initiated by the SER (Social and Economic Council of the Netherlands). The report gives background information on the evaluation of measures in the agreement aimed at the built environment. It is an annex of the general evaluation of PBL/ECN [Dutch] Dit rapport is geschreven als onderdeel van de ondersteuning door ECN en PBL bij het tot stand komen van het energieakkoord in de periode maart tot september 2013. Dit rapport dient als achtergrond bij de doorrekening van de maatregelen gericht op energiebesparing in de gebouwde omgeving.

  13. Detection of Bacillus anthracis Spores Using Peptide Functionalized SERS-Active Substrates

    Directory of Open Access Journals (Sweden)

    Atanu Sengupta

    2012-01-01

    Full Text Available The need for portable technologies that can rapidly identify biological warfare agents (BWAs in the field remains an international priority as expressed at the 2011 Biological Weapons Convention. In recent years, the ability of surface-enhanced Raman spectroscopy (SERS to rapidly detect various BWAs at very low concentrations has been demonstrated. However, in the specific case of Bacillus anthracis, differentiation at the species level is required since other bacilli are common in the environment, representing potential false-positive responses. To overcome this limitation, we describe the use of a peptide attached to the SERS-active metal that selectively binds Bacillus anthracis-Sterne as the target analyte. Using this approach, 109  B. anthracis-Sterne spores/mL produced an intense dipicolinic acid spectrum upon the addition of acetic acid, while the same concentration and treatment of B. cereus and B. subtilis did not.

  14. Heparin Assisted Photochemical Synthesis of Gold Nanoparticles and Their Performance as SERS Substrates

    Directory of Open Access Journals (Sweden)

    Maria del Pilar Rodríguez-Torres

    2014-10-01

    Full Text Available Reactive and pharmaceutical-grade heparins were used as biologically compatible reducing and stabilizing agents to photochemically synthesize colloidal gold nanoparticles. Aggregates and anisotropic shapes were obtained photochemically under UV black-light lamp irradiation (λ = 366 nm. Heparin-functionalized gold nanoparticles were characterized by Scanning Electron Microscopy and UV-Vis spectroscopy. The negatively charged colloids were used for the Surface Enhanced Raman Spectroscopy (SERS analysis of differently charged analytes (dyes. Measurements of pH were taken to inspect how the acidity of the medium affects the colloid-analyte interaction. SERS spectra were taken by mixing the dyes and the colloidal solutions without further functionalization or addition of any aggregating agent.

  15. Pensamiento neoliberal: un acercamiento a la concepción de sociedad y de ser humano

    Directory of Open Access Journals (Sweden)

    Millán La Rivera, Cecilia

    2015-02-01

    Full Text Available En este artículo se describe desde el pensamiento neoliberal la concepción de sociedad y de ser humano que tiene dicho modelo. Descripción que se hace a partir de los escritos de dos de los economistas más representativos del pensamiento neoliberal: Ludwig Von Mises y Friedrich Hayek. Se inicia con una breve contextualización del origen del Neoliberalismo, para luego presentar las dos tesis expuestas por ellos: El ser humano antes que nada un individuo y la racionalidad del individuo. Se finaliza con una breve reflexión crítica sobre algunas ideas de ambas premisas.

  16. Quantitative detection of liver-relevant biomarkers by SERS-immunolabeled gold nanoparticles

    Science.gov (United States)

    Payne, William Mark

    Lab-on-a-chip technology has the potential to rapidly change the way experiments are conducted in a variety of fields ranging from medicine to environmental science. Specifically, sensors, detectors, and monitoring devices are increasingly being miniaturized to perform many experiments or measurements on a single chip. In this research, we develop an immunolabeled gold nanoparticle complex capable of detecting liver organoid biomarkers intended for use in a microfluidic device. Human Serum Albumin (HSA) and alpha-Glutathione S-Transferase (alpha-GST) are liver biomarkers that indicate liver health and damage respectively. Herein we demonstrate detection of the liver organoid biomarkers at nanomolar concentrations. Through plasmonic coupling induced by aggregation in the presence of analyte, the SERS signal obtained from the nanoparticles is dramatically increased. Furthermore, detection is demonstrated in a simple fluidic device to show the feasibility of implementing an optimized SERS-immunolabeled nanoparticle for translational application.

  17. SERS-active nanoparticles as a barcoding technology for tags and seals

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Leif O [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Merkle, Peter B [SNL

    2009-01-01

    In this paper, we present our work to modernize tagging and sealing technologies for international safeguards applications. Our work combines technologies developed at both Los Alamos National Laboratory (LANL), and Sandia National Laboratories (SNL), to offer a passive tag and seal system that can be applied and verified in field, with minimal training for on-site personnel, along with a low per-seal cost. Here, we focus primarily on LANL technology: the use of Surface Enhanced Raman Scattering (SERS) as an inexpensive verification tool. Our nanoparticles offer unique SERS responses, which we can then use to incorporate robust barcoding into tag materials. We describe this technology in more detail, offer preliminary results, and outline integration with SNL developments.

  18. Tornar-se uma outra na histeria e ser uma outra do falso self

    Directory of Open Access Journals (Sweden)

    Teresa Pinheiro

    Full Text Available Este trabalho pretende fazer uma comparação entre a histeria e o falso self a partir do projeto de “ser uma outra” presente nas duas patologias. O projeto de “tornar-se uma outra” na histeria aponta para personagens que necessariamente estão presentes nesse modelo fantasmático: a vítima e o vilão. A noção de “ser uma outra”, no falso-self, apresenta-se como única forma possível de estar no mundo, onde a ilusão não tem lugar.

  19. Optical Characterization of SERS Substrates Based on Porous Au Films Prepared by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    V. V. Strelchuk

    2015-01-01

    Full Text Available The SERS (surface enhanced Raman spectroscopy substrates based on nanocomposite porous films with gold nanoparticles (Au NPs arrays were formed using the method of the pulsed laser deposition from the back low-energy flux of erosion torch particles on the glass substrate fixed at the target plain. The dependencies of porosity, and morphology of the surface of the film regions located near and far from the torch axis on the laser ablation regime, laser pulses energy density, their number, and argon pressure in the vacuum chamber, were ascertained. The Au NPs arrays with the controllable extinction spectra caused by the local surface plasmon resonance were prepared. The possibility of the formation of SERS substrates for the detection of the Rhodamine 6G molecules with the concentration 10−10 Mol/L with the enhancement factor 4·107 was shown.

  20. Recent progress on the structure of Ser/Thr protein phosphatases

    Institute of Scientific and Technical Information of China (English)

    WANG BaiJing; ZHANG Peng; WEI Quni

    2008-01-01

    PP1, PP2A and PP2B, belonging to the PPP family of Ser/Thr protein phosphatases, participate in regulating many important physiological processes, such as cell cycle control, regulation of cell growth and division regulation, etc. The sequence homology between them is relatively high, and ter-tiary structure is conserved. Because of the complexity of the structure of PP2A and the diversity of its regulatory subunits, its structure is less well known than those of PP1 and PP2B. The PP2A holoen-zyme consists of a heterodimeric core enzyme, comprising a scaffolding subunit and a catalytic sub-unit, as well as a variable regulatory subunit. In this study, the subunit compositions, similarities and differences between the Ser/Thr protein phsphatases structures are summarized.

  1. Recent progress on the structure of Ser/Thr protein phosphatases

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    PP1, PP2A and PP2B, belonging to the PPP family of Ser/Thr protein phosphatases, participate in regulating many important physiological processes, such as cell cycle control, regulation of cell growth and division regulation, etc. The sequence homology between them is relatively high, and ter- tiary structure is conserved. Because of the complexity of the structure of PP2A and the diversity of its regulatory subunits, its structure is less well known than those of PP1 and PP2B. The PP2A holoen- zyme consists of a heterodimeric core enzyme, comprising a scaffolding subunit and a catalytic sub- unit, as well as a variable regulatory subunit. In this study, the subunit compositions, similarities and differences between the Ser/Thr protein phsphatases structures are summarized.

  2. Phenomenological features of dreams: Results from dream log studies using the Subjective Experiences Rating Scale (SERS).

    Science.gov (United States)

    Kahan, Tracey L; Claudatos, Stephanie

    2016-04-01

    Self-ratings of dream experiences were obtained from 144 college women for 788 dreams, using the Subjective Experiences Rating Scale (SERS). Consistent with past studies, dreams were characterized by a greater prevalence of vision, audition, and movement than smell, touch, or taste, by both positive and negative emotion, and by a range of cognitive processes. A Principal Components Analysis of SERS ratings revealed ten subscales: four sensory, three affective, one cognitive, and two structural (events/actions, locations). Correlations (Pearson r) among subscale means showed a stronger relationship among the process-oriented features (sensory, cognitive, affective) than between the process-oriented and content-centered (structural) features--a pattern predicted from past research (e.g., Bulkeley & Kahan, 2008). Notably, cognition and positive emotion were associated with a greater number of other phenomenal features than was negative emotion; these findings are consistent with studies of the qualitative features of waking autobiographical memory (e.g., Fredrickson, 2001).

  3. An operando surface enhanced Raman spectroscopy (SERS) study of carbon deposition on SOFC anodes.

    Science.gov (United States)

    Li, Xiaxi; Liu, Mingfei; Lee, Jung-pil; Ding, Dong; Bottomley, Lawrence A; Park, Soojin; Liu, Meilin

    2015-09-07

    Thermally robust and chemically inert Ag@SiO2 nanoprobes are employed to provide the surface enhanced Raman scattering (SERS) effect for an in situ/operando study of the early stage of carbon deposition on nickel-based solid oxide fuel cell (SOFC) anodes. The enhanced sensitivity to carbon enables the detection of different stages of coking, offering insights into intrinsic coking tolerance of material surfaces. Application of a thin coating of gadolinium doped ceria (GDC) enhances the resistance to coking of nickel surfaces. The electrochemically active Ni-YSZ interface appears to be more active for hydrocarbon reforming, resulting in the accumulation of different hydrocarbon molecules, which can be readily removed upon the application of an anodic current. Operando SERS is a powerful tool for the mechanistic study of coking in SOFC systems. It is also applicable to the study of other catalytic and electrochemical processes in a wide range of conditions.

  4. Gold nanomaterials for the selective capturing and SERS diagnosis of toxins in aqueous and biological fluids

    DEFF Research Database (Denmark)

    Hassanain, Waleed A.; Izake, Emad L.; Schmidt, Michael Stenbæk

    2017-01-01

    A highly sensitive nanosensing method for the combined selective capture and SERS detection of Microcystin-LR (MC-LR) in blood plasma has been developed. The new method utilizes gold coated magnetic nanoparticles that are functionalized with anti MC-LR antibody Fab' fragments for the selective...... the extractor nanoparticles within 5min by manipulating the pH environment of the nanoparticles. The regenerated extractor nanoparticles maintained their capture efficiency and, therefore, were re-used to capture of MC-LR from successive samples. The released purified toxin was screened within 10min on gold...... was 10fM (R2=0.9975) which is well below the clinically required detection limit of the toxin. The SERS determination of MC-LR was cross validated against ELISA. By using antibody fragments that are specific to the target biomolecule, the new methodology can be extended to the rapid extraction...

  5. First observation of Hb Tunis [beta124(H2Pro>Ser] in Turkey

    Directory of Open Access Journals (Sweden)

    Aylin Köseler

    2010-06-01

    Full Text Available Hb Tunis [beta124(H2Pro>Ser] was reported from Tunisia in 1988. This hemoglobin variant was detected by isoelectric focusing moving just ahead of Hb A. It cannot be identified by standard hemoglobin electrophoresis due to its similar mobility to Hb A. It has normal stability and oxygen affinity and does not produce any clinical symptoms. Here, we report a heterozygous Hb Tunis [beta124(H2Pro>Ser] case discovered for the first time in Turkey in a premarital screening program. This hemoglobin variant can be identified with high performance liquid chromatography analysis confirmed with DNA sequencing. We emphasize in our study the importance of an interdisciplinary collaborative study at the provincial basis for the success of the hemoglobinopathy control program.

  6. Representações sociais de adolescentes sobre ser saudável

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Santos da Silva

    2014-04-01

    Full Text Available Esse estudo objetivou apreender o conteúdo representacional do ser saudável segundo a ótica de adolescentes. Pesquisa qualitativa, descritiva e exploratória, ancorada na abordagem dimensional da Teoria das Representações Sociais. Participaram da entrevista semiestruturada 24 adolescentes, sendo, posteriormente, aplicada a técnica de análise de conteúdo. Na construção do ser saudável, nas representações dos adolescentes, se integram multidimensões da vida humana, relacionadas e condicionadas por determinantes de ordem político-social, cultural e econômica, explicitadas por necessidade de saúde que envolve alimentação, prática de atividade física, cuidados com a saúde, dentre outros.

  7. Eficacia Análgesica del Láser de Baja Potencia en Ortodoncia

    OpenAIRE

    Artés Ribas, Montserrat

    2014-01-01

    Es va realitzar estudi clínic . L' objectiu de l'estudi va ser avaluar la sensació dolorosa que apareix en els pacients d'ortodòncia en col • locar elàstics de separació entre molars i premolars i determinar el grau d'eficàcia analgèsica del làser de baixa potència ( LLLT ) amb dues longituds d'ona diferents, una de 830 nm i l'altra de 660nm , comparant-lo amb un placebo . Material i Mètodes - L'estudi es va realitzar amb dos grups , cadascun de 20 voluntaris ( 6 homes , 14 dones ) , tots ell...

  8. Simple fabrication of Ag nanoparticle-impregnated electrospun nanofibres as SERS substrates

    Indian Academy of Sciences (India)

    Altangerel Amarjargal; Leonard D Tijing; Cheol Sang Kim

    2015-02-01

    A facile method for the fabrication of electrospun polyurethane (PU) nanofibres impregnated with Ag nanoparticles (NPs) as an efficient and free-standing surface-enhanced Raman scattering (SERS) substrates is reported here. Electrospinning was used to produce polymeric nanofibrous matrix, while a liquid polyol(ethylene glycol) solvent under low temperature was used not only to reduce Ag+ to Ag0, but also was employed as the in situ growth medium for well-dispersed Ag NPs on the surface of fibre nets. Large enhancement in Raman signals of 4-mercaptobenzoic acid analytes could be realized in the present Ag/PU nanofibres due to the presence of SERS ‘hotspots’ by means of appropriate interparticle gap.

  9. Adapting and testing a portable Raman spectrometer for SERS analysis of amino acids and small peptides

    Science.gov (United States)

    Brambilla, A.; Philippidis, A.; Nevin, A.; Comelli, D.; Valentini, G.; Anglos, D.

    2013-07-01

    Surface-Enhanced Raman Spectroscopy (SERS), a powerful spectrochemical technique enabling highly sensitive analysis of organic and biological materials, is investigated for applications in the analysis of archaeological materials including in situ screening. In this work, a compact mobile Raman spectrometer is employed for acquiring Surface-Enhanced Raman spectra from natural amino acids (L-Arg, L-Phe, L-Met) and a tripeptide (Glutathione), adsorbed on silver colloids. The detection limits of the portable Raman spectrometer, together with an optimization of sample preparation and experimental parameters, are reported. The collection and interpretation of SER spectra of amino acids and peptides is a starting point for the optimization of the instrumentation and its application in the study of more complex biological molecules in the context of detection and analysis of archaeological materials and residues.

  10. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    DEFF Research Database (Denmark)

    Lauridsen, Rikke Kragh; Madsen Sommer, Lea Mette; Johansen, Helle Krogh

    2017-01-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage....... The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm-1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After...... long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children...

  11. Heparin Assisted Photochemical Synthesis of Gold Nanoparticles and Their Performance as SERS Substrates

    Science.gov (United States)

    Rodríguez-Torres, Maria del Pilar; Díaz-Torres, Luis Armando; Romero-Servin, Sergio

    2014-01-01

    Reactive and pharmaceutical-grade heparins were used as biologically compatible reducing and stabilizing agents to photochemically synthesize colloidal gold nanoparticles. Aggregates and anisotropic shapes were obtained photochemically under UV black-light lamp irradiation (λ = 366 nm). Heparin-functionalized gold nanoparticles were characterized by Scanning Electron Microscopy and UV-Vis spectroscopy. The negatively charged colloids were used for the Surface Enhanced Raman Spectroscopy (SERS) analysis of differently charged analytes (dyes). Measurements of pH were taken to inspect how the acidity of the medium affects the colloid-analyte interaction. SERS spectra were taken by mixing the dyes and the colloidal solutions without further functionalization or addition of any aggregating agent. PMID:25342319

  12. Tunable SERS-Tags-Hidden Gold Nanorattles for Theranosis of Cancer Cells with Single Laser Beam

    Science.gov (United States)

    Chen, Zhaolong; Yu, Dexin; Huang, Yu; Zhang, Zhengjun; Liu, Ting; Zhan, Jinhua

    2014-10-01

    With the use of gold nanostructures, photothermal therapy (PTT) of cancer has great advantages compared to conventional methods, such as noninvasive targeted destruction and easily operation. Generally speaking, respective diagnosis and therapy of tumor require at least two instruments, leading to incongruence of tumor borders between diagnosis and therapy. To tackle this problem, tunable SERS-tags-hidden gold nanorattles (STHGNRs) have been designed and developed here for theranosis of cancer with single laser beam. The surface plasma resonance peak of STHGNRs can be tuned from visible region to near-infrared region by controlling the cavity size and shell thickness. The outer shells not only improve the stability of the SERS reporters but also enhance the brightness by more than two order magnitude compared to gold nanoparticles. In vitro study, immuno STHGNRs can serve as theranosis agents simultaneously for sensitive and efficient theranosis of cancer cells.

  13. Spectroscopy on the wing: naturally inspired SERS substrates for biochemical analysis.

    Science.gov (United States)

    Garrett, Natalie L; Vukusic, Peter; Ogrin, Feodor; Sirotkin, Evgeny; Winlove, C Peter; Moger, Julian

    2009-03-01

    We show that naturally occurring chitinous nanostructures found on the wings of the Graphium butterfly can be used as substrates for surface-enhanced Raman scattering when coated with a thin film of gold or silver. The substrates were found to exhibit excellent biocompatibility and sensitivity, making them ideal for protein assaying. An assay using avidin/biotin binding showed that the substrates could be used to quantify protein binding directly from changes in the surface-enhanced Raman scattering (SERS) spectra and were sensitive over a concentration range comparable with a typical enzyme-linked immunosorbent assays (ELISA) assay. A biomimetic version of the wing nanostructures produced using a highly reproducible, large-scale fabrication process, yielded comparable enhancement factors and biocompatibility. The excellent biocompatibility of the wings and biomimetic substrates is unparalleled by other lithographically produced substrates, and this could pave the way for widespread application of ultrasensitive SERS-based bioassays.

  14. Detection and quantification of dithiocarbamate pesticides by Surface Enhanced Raman Spectroscopy (SERS)

    Science.gov (United States)

    Saute, Benjamin Calvin

    Dithiocarbamates are a subclass of carbamate pesticides that are widely used as insecticidal agents on food crops in the US and abroad. Quantitative determination of trace quantities of dithiocarbamates is necessary in order to mitigate potential human exposure via pesticide residues left on inadequately washed food items as well as groundwater contamination from agricultural runoff. The focus of this research is on the development and optimization of a Surface Enhanced Raman Spectroscopy (SERS) based analytical technique for the quantitative determination of trace amounts of dithiocarbamate pesticides in different matrices. Gold nanoparticles of different shapes and sizes will be investigated to determine the suitability of these materials as SERS active substrates for the trace analysis of dithiocarbamate pesticides. Analytical sensitivity will be evaluated by determining the limits of detection using established statistical methods.

  15. Electrochemically Created Highly Surface Roughened Ag Nanoplate Arrays for SERS Biosensing Applications

    OpenAIRE

    Yang, Shikuan; Slotcavage, Daniel; Mai, John D.; Guo, Feng; Li, Sixing; Zhao, Yanhui; Lei, Yong; Cameron, Craig E.; Huang, Tony Jun

    2014-01-01

    Highly surface-roughened Ag nanoplate arrays are fabricated using a simple electrodeposition and in situ electrocorrosion method with inorganic borate ions as capping agent. The electrocorrosion process is induced by a change in the local pH value during the electrochemical growth, which is used to intentionally carve the electrodeposited structures. The three dimensionally arranged Ag nanoplates are integrated with substantial surface-enhanced Raman scattering (SERS) hot spots and are free o...

  16. De Ser e Tempo aos Beiträge zur Philosophie

    Directory of Open Access Journals (Sweden)

    Jordino Marques

    2007-12-01

    Full Text Available O autor procura desenvolver a relação existente essas duas obras,levando em conta que o próprio Heidegger manifestara um desejo de que os Beiträge zur Philosophie fossem sua segunda obra mais importante, já que, atrávés dela, esclarecem-se muitas orientações que em Ser e Tempo foram apenas indicadas. 

  17. NZ Ser: the results of the analysis of the 25 years photometric activity

    Science.gov (United States)

    Barsunova, O.; Mel'nikov, S.; Grinin, V.; Katysheva, N.; Shugarov, S.

    2014-03-01

    We present the analysis of the long-term photometric variability of NZ Ser. The object shows both large-scale cyclic variability and low-amplitude Algol-like, fading typical for UX Ori stars. The variations of the stellar brightness are accompanied by variations of the B-V and V-R colors: when the brightness decreases, B-V decreases, while V-R increases.

  18. Towards quantitative SERS detection of hydrogen cyanide at ppb level for human breath analysis

    Directory of Open Access Journals (Sweden)

    Rikke Kragh Lauridsen

    2015-09-01

    Full Text Available Lung infections with Pseudomonas aeruginosa (PA is the most common cause of morbidity and mortality in cystic fibrosis (CF patients. Due to its ready adaptation to the dehydrated mucosa of CF airways, PA infections tend to become chronic, eventually killing the patient. Hydrogen cyanide (HCN at ppb level has been reported to be a PA biomarker. For early PA detection in CF children not yet chronically lung infected a non-invasive Surface-Enhanced Raman Spectroscopy (SERS-based breath nanosensor is being developed. The triple bond between C and N in cyanide, with its characteristic band at ∼2133 cm−1, is an excellent case for the SERS-based detection due to the infrequent occurrence of triple bonds in nature. For demonstration of direct HCN detection in the gas phase, a gold-coated silicon nanopillar substrate was exposed to 5 ppm HCN in N2. Results showed that HCN adsorbed on the SERS substrate can be consistently detected under different experimental conditions and up to 9 days after exposure. For detection of lower cyanide concentrations serial dilution experiments using potassium cyanide (KCN demonstrated cyanide quantification down to 1 μM in solution (corresponding to 18 ppb. Lower KCN concentrations of 10 and 100 nM (corresponding to 0.18 and 1.8 ppb produced SERS intensities that were relatively similar to the reference signal. Since HCN concentration in the breath of PA colonized CF children is reported to be ∼13.5 ppb, the detection of cyanide is within the required range.

  19. Characterization of Ser73 in Arabidopsis thaliana Glutathione S-transferase zeta class

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Glutathione S-transferases (GSTs) are ubiquitous detoxifying superfamily enzymes. The zeta class GST from Arabidopsis thaliana (AtGSTZ) can efficiently degrade dichloroacetic acid (DCA), which is a common carcinogenic contaminant in drinking water. Ser73 in AtGSTZ is a conserved residue at Glutathione binding site (G-site). Compared with the equivalent residues in other GSTs, the catalytic and structural properties of Ser73 were poorly investigated. In this article, site-saturation mutagenesis was performed to characterize the detailed role of Ser73. The DCA de.chlorinating (DCA-DC) activity showed that most of the mutants had less than 3% of the wild-type activity, except S73T and $73A showing 43.48% and 21.62% of the wild-type activity, respectively, indicating that position 73 in AtGSTZ showed low mutational substitutability. Kinetic experiments revealed that mutants S73T, $73A, and S73G showed low binding affinity and catalytic efficiency toward DCA, 1.8-, 3.1-, and 10.7- fold increases in KmDcA values and 4.0-, 9.6-, and 34.1- fold decreases in KcatDCA/KmDCA values, respectively, compared to the wild type. Thermostability and refolding experiments showed that the wild type maintalned more thermostability and recovered activity. These results demonstrated the important role of Set73 in catalytic activity and structural stability of the enzyme. Such properties of Set73 could be particularly crucial to the molecular evolution of AtGSTZ and might,therefore, help explain why Ser73 is conserved in all GSTs. This conclusion might provide insights into the directed evolution of the DCA-DC activity of AtGSTZ.

  20. Collaborative tools for an institutional repository - JuSER, pubdb and all that...

    OpenAIRE

    Wagner, Alexander

    2013-01-01

    This talk gives an overview of the collaborative featrues of JuSER and it's sister systems. After a short introduction of the publications database and the institutional repository, and why they should interact, the main topic are the private collections, known in Jülich as institute collections, and how they can be used in a scientific publication workflow. Input routines are outlined with a special emphasise on the possiblity to import data. Finally a short introduction to groups and basket...

  1. Valoración del aprendizaje en el ser humano, un reto de los maestros

    OpenAIRE

    Cruz Muñoz, María del Pilar

    2015-01-01

    tesis: (Especialización en Evaluación Pedagógica). Universidad Católica de Manizales. Facultad de educación, 2015 En esta monografía se presenta la importancia de la valoración del aprendizaje en el ser humano, como un reto de los maestros para que desde el inicio de la labor educativa se le tenga en cuenta, como una estrategia para conocer el interés del educando.

  2. SERS active self-assembled diphenylalanine micro/nanostructures: A combined experimental and theoretical investigation

    Science.gov (United States)

    Kogikoski, Sergio; Khanra, Soma; Alves, Wendel A.; Guha, Suchismita

    2017-08-01

    Enhancing Raman signatures of molecules by self-assembled metal nanoparticles, nanolithography patterning, or by designing plasmonic nanostructures is widely used for detection of low abundance biological systems. Self-assembled peptide nanostructures provide a natural template for tethering Au and Ag nanoparticles due to its fractal surface. Here, we show the use of L,L-diphenylalanine micro-nanostructures (FF-MNSs) for the organization of Ag and Au nanoparticles (Nps) and its potential as surface-enhanced Raman scattering (SERS)-active substrates. The FF-MNSs undergo an irreversible phase transition from hexagonally packed (hex) micro-nanotubes to an orthorhombic (ort) structure at ˜150 °C. The metal Nps form chains on hex FF-MNSs as inferred from transmission electron microscopy images and a uniform non-aggregated distribution in the ort phase. The high luminescence from the ort FF-MNS phase precludes SERS measurements with AgNps. The calculated Raman spectra using density-functional theory shows a higher intensity from rhodamine 6G (R6G) molecule in the presence of an Ag atom bound to ort FF compared with hex FF. The SERS spectra obtained from R6G bound to FF-MNSs with AuNps clearly show a higher enhancement for the ort phase compared with hex FF, corroborating our theoretical calculations. Our results indicate that FF-MNSs both in the hex and ort phases can be used as substrates for the SERS analysis with different metal nanoparticles, opening up a novel class of optically active bio-based substrates.

  3. Tunable SERS-Tags-Hidden Gold Nanorattles for Theranosis of Cancer Cells with Single Laser Beam

    OpenAIRE

    2014-01-01

    With the use of gold nanostructures, photothermal therapy (PTT) of cancer has great advantages compared to conventional methods, such as noninvasive targeted destruction and easily operation. Generally speaking, respective diagnosis and therapy of tumor require at least two instruments, leading to incongruence of tumor borders between diagnosis and therapy. To tackle this problem, tunable SERS-tags-hidden gold nanorattles (STHGNRs) have been designed and developed here for theranosis of cance...

  4. Medicina Interna: ser original es volver a los orígenes

    Directory of Open Access Journals (Sweden)

    2015-06-01

    Full Text Available La primera acepción que el Diccionario de la Real Academia Española da para el calificativo originalno es la de novedoso sino la de perteneciente o relativo al origen. La Medicina Interna tiene sus orígenes bien definidos y sería un error olvidarlos. Una cosa es adaptarse a los tiempos y a sus necesidades y otra bien distinta es renunciar a los propios principios

  5. Porous plasmonic nanocomposites for SERS substrates fabricated by two-step laser method

    Energy Technology Data Exchange (ETDEWEB)

    Koleva, M.E., E-mail: mihaela_ek@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan); Nedyalkov, N.N.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee blvd., Sofia 1784 (Bulgaria); Gerlach, J.W.; Hirsch, D.; Prager, A.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, D-04318 Leipzig (Germany); Fukata, N.; Jevasuwan, W. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 (Japan)

    2016-04-25

    This research is focused on investigation of coupled plasmonic/metal-semiconductor nanomaterials. A two-step laser-assisted method is demonstrated for formation of plasmonic Ag nanoparticles (NPs) distributed into porous metal–oxide semiconductors. The mosaic Ag-ZnO target is used for laser ablation and, subsequently, laser annealing of the deposited layer is applied. The plasmon resonance properties of the nanostructures produced are confirmed by optical transmission spectroscopy. The wurtzite structure of ZnO is formed with tilted c-axis orientation and, respectively, a mixed Raman mode appears at 580 cm{sup −1}. The oxygen pressure applied during a deposition process has impact on the morphology and thickness of the porous nanostructures, but not on the size and size distribution of AgNPs. The porous nanocomposites exhibited potential for SERS applications, most pronounced for the oxygen deficient sample, grown at lower oxygen pressure. The observed considerable SERS enhancement of R6G molecules on AgNP/ZnO can be attributed to the ZnO-to-molecule charge transfer contribution, enhanced by the additional electrons from the local surface plasmon resonance (LSPR) of AgNPs to the ZnO through the conduction band. - Highlights: • Porous AgNPs/ZnO composites are obtained by laser deposition and laser annealing. • Morphology and properties depend on growth oxygen pressure. • The emergence of mixed-symmetry Raman mode at 580 cm{sup −1} is registered. • The AgNPs/ZnO porous nanocomposites are suitable for SERS-active substrates. • The charge transfer enhanced by LSPR has a contribution to SERS effect.

  6. Nanoporous Silver Film Fabricated by Oxygen Plasma: A Facile Approach for SERS Substrates.

    Science.gov (United States)

    Ma, Chaoxiong; Trujillo, Michael J; Camden, Jon P

    2016-09-14

    Nanoporous metal films are promising substrates for surfaced-enhanced Raman scattering (SERS) measurement, owing to their homogeneity, large surface area, and abundant hot-spots. Herein, a facile procedure was developed to fabricate nanoporous Ag film on various substrate surfaces. Thermally deposited Ag film was first treated with O2 plasma, resulting in porous Ag/AgxO film (AgxO-NF) with nanoscale feature. Sodium citrate was then used to reduce AgxO to Ag, forming nanoporous Ag film (AgNF) with similar morphology. The AgNF substrate demonstrates 30-fold higher Raman intensity than Ag film over polystyrene nanospheres (d = 600 nm) using 4-mercaptobenzoic acid (4-MBA) as the sensing molecule. Comparing with ordinary Raman measurement on 4-MBA solution, an enhancement factor of ∼6 × 10(6) was determined for AgNF. The AgNF substrate was evaluated for benzoic acid, 4-nitrophenol, and 2-mercaptoethanesulfonate, showing high SERS sensitivity for chemicals that bind weakly to Ag surface and molecules with relatively small Raman cross section at micromolar concentration. In addition to its simplicity, the procedure can be applied to various materials such as transparency film, filter paper, hard polystyrene film, and aluminum foil, revealing similar Raman sensitivity. By testing the durability of the substrate, we found that the AgxO films can be stored in ambient conditions for more than 90 days and still deliver the same SERS intensity if the films are treated with sodium citrate before use. These results demonstrate the advantage of the proposed approach for mass production of low-cost, sensitive, and durable SERS substrates. The transferable nature of these AgNF to different flexible surfaces also allows their easy integration with other sensing schemes.

  7. Similarities and differences in the spectral behavior of W Ser and UX Mon in the ultraviolet

    Science.gov (United States)

    Sanad, M. R.; Bobrowsky, M.

    2013-04-01

    We present ultraviolet spectra of two eclipsing interacting binary systems, W Ser and UX Mon, with good coverage over the 14.16-day and 5.9-day orbital periods, respectively, using observations taken by the International Ultraviolet Explorer ( IUE) during the period between 1978-1993 and 1981-1991. Two profiles of W Ser and UX Mon showing variations of line fluxes at two orbital phases are presented. This paper focuses on the N V emission line at 1240 Å, C II emission line at 1336 Å, C IV emission line at 1550 Å, O III emission line at 1666 Å and the Si III emission line at 1892 Å, produced in an extended gaseous envelope around the mass-gaining component by calculating spectral line fluxes. Our results show that there are variations of line fluxes with time, similar to the light curves found for both W Ser and UX Mon. We attribute these spectral variations to eclipse effects and to variations in the mass transfer rate. These results from the IUE observations support the thick disk model around the primary star in which variations of mass transfer affect the observed radiation from the gaseous envelope around the hot star. Future, high-resolution imaging is recommended to confirm the inferred asymmetrical circumstellar envelopes.

  8. Similarities and Differences in Spectral Behavior Between W Ser and UX Mon in the UV

    Science.gov (United States)

    Bobrowsky, Matthew; Sanad, M. R.

    2012-01-01

    We present ultraviolet spectra of two eclipsing interacting binary systems, W Ser and UX Mon. The data contain good coverage over the 14.16-day and 5.9-day orbital periods, respectively, using observations taken by the International Ultraviolet Explorer (IUE) during periods between 1978 - 1993 and 1981 - 1991 for the two systems respectively. Two profiles of both W Ser and UX Mon showing variations of line fluxes at two orbital phases are presented. We investigated the N V emission line at 1240 Å, C II emission line at 1336 Å, C IV emission line at 1550 Å, O III emission line at 1666 Å, and Si III emission line at 1892 Å (which are produced in an extended gaseous envelope around the mass-gaining component), by calculating the line fluxes of these spectral lines. Our results show that there are spectral variations of line fluxes at different orbital phases, correlated with the light curves found for both W Ser and UX Mon. We attribute these spectral variations to effects from the eclipse and to variations in the mass transfer rate. M.B. acknowledges support from NASA, through grant number HST-AR-10304.04-A from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  9. Chemiresistive/SERS dual sensor based on densely packed gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Sanda Boca

    2015-12-01

    Full Text Available Chemiresistors are a class of sensitive electrical devices capable of detecting (biochemicals by simply monitoring electrical resistance. Sensing based on surface enhanced Raman scattering (SERS represents a radically different approach, in which molecules are optically detected according to their vibrational spectroscopic fingerprint. Despite different concepts are involved, one can find in the literature examples from both categories reporting sensors made of gold nanoparticles. The same building blocks appear because both sensor classes share a common principle: nanometric interparticle gaps are needed, for electron tunneling in chemiresistors, and for enhancing electromagnetic fields by plasmon coupling in SERS-based sensors. By exploiting such nano-gaps in self-assembled films of gold nanoparticles, we demonstrate the proof of concept of a dual electrical/optical sensor, with both chemiresistive and SERS capabilities. The proposed device is realized by self-assembling 15 nm gold nanoparticles into few micrometers-wide strips across commercially available interdigitated electrodes. The dual-mode operation of the device is demonstrated by the detection of a biologically relevant model analyte, 4-mercaptophenyl boronic acid.

  10. LA ELOCUENCIA, SISTEMA DE VIDA ÍNSITO EN EL SER HUMANO

    Directory of Open Access Journals (Sweden)

    Bulmaro Reyes Coria

    2013-01-01

    Full Text Available Resumen Este artículo se funda en el repaso directo de las preceptivas retóricas aristotélica y ciceroniana, incluida la Retórica a Herenio. Pretende mostrar que la elocuencia, o retórica, no es una simple asignatura escolar que se desliga de la esencia del ser humano, sino un sistema que le es inherente a este. Tal sistema es capaz de ser cultivado y fortalecido por el estudio o la ejercitación, y estas dos tareas constituyen el lugar donde se nutre la invención: ahí se hace evidente la materia prima de los entimemas, ahí el ser humano cobra consciencia de que ese otro sistema es parte de su integridad, a pesar de que le sea intangible al tacto, como lo era para Sancho, quien, sin embargo, no podía vivir sin hablar ni siquiera contra los mandatos del amo.

  11. SERS detection of the biomarker hydrogen cyanide from Pseudomonas aeruginosa cultures isolated from cystic fibrosis patients

    Science.gov (United States)

    Lauridsen, Rikke Kragh; Sommer, Lea M.; Johansen, Helle Krogh; Rindzevicius, Tomas; Molin, Søren; Jelsbak, Lars; Engelsen, Søren Balling; Boisen, Anja

    2017-03-01

    Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm-1 in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate. After long-term infection, a mutation in the patho-adaptive lasR gene can alter the expression of HCN, which is why it is sometimes not possible to detect HCN in the breath of chronically infected patients. Four P. aeruginosa reference strains and 12 clinical P. aeruginosa strains isolated from CF children were evaluated, and HCN was clearly detected from overnight cultures of all wild type-like isolates and half of the later isolates from the same patients. The clinical impact could be that P. aeruginosa infections could be detected at an earlier stage, because daily breath sampling with an immediate output could be possible with a point-of-care SERS device.

  12. Ultrasensitive SERS performance in 3D "sunflower-like" nanoarrays decorated with Ag nanoparticles.

    Science.gov (United States)

    Zhang, Xiaolei; Xiao, Xiangheng; Dai, Zhigao; Wu, Wei; Zhang, Xingang; Fu, Lei; Jiang, Changzhong

    2017-03-02

    Low-cost, stabilized and ultrasensitive three-dimensional (3D) hierarchical surface-enhanced Raman scattering substrates ("sunflower-like" nanoarrays decorated with Ag nanoparticles, denoted as SLNAs-Ag) have been obtained by fabricating binary colloidal crystals and then decorating with Ag nanoparticles. In order to provide a larger density of hot spots within the laser-illumination area, the silica sphere arrays were chosen as the island-type platform for the polystyrene (PS) nanosphere deposition, and the distances between the PS nanospheres were tuned by etching for different durations. Compared with conventional 2D planar systems, the as-fabricated 3D SLNAs-Ag exhibited extremely high SERS sensitivity ascribed to the larger SERS active regions. Quantitative detection of molecules with an extremely low incident laser power was achieved on the "sunflower-like" nanoarrays in which the PS nanospheres were etched for 5 minutes and decorated with Ag nanoparticles, and the corresponding analytical enhancement factor is calculated to be 2 × 10(14) with the concentration of rhodamine 6G down to 10(-15) M. Based on the achieved SERS substrates, we have further demonstrated the highly sensitive detection of molecules such as melamine for food safety inspection.

  13. Method for assessing the reliability of molecular diagnostics based on multiplexed SERS-coded nanoparticles.

    Directory of Open Access Journals (Sweden)

    Steven Y Leigh

    Full Text Available Surface-enhanced Raman scattering (SERS nanoparticles have been engineered to generate unique fingerprint spectra and are potentially useful as bright contrast agents for molecular diagnostics. One promising strategy for biomedical diagnostics and imaging is to functionalize various particle types ("flavors", each emitting a unique spectral signature, to target a large multiplexed panel of molecular biomarkers. While SERS particles emit narrow spectral features that allow them to be easily separable under ideal conditions, the presence of competing noise sources and background signals such as detector noise, laser background, and autofluorescence confounds the reliability of demultiplexing algorithms. Results obtained during time-constrained in vivo imaging experiments may not be reproducible or accurate. Therefore, our goal is to provide experimentalists with a metric that may be monitored to enforce a desired bound on accuracy within a user-defined confidence level. We have defined a spectral reliability index (SRI, based on the output of a direct classical least-squares (DCLS demultiplexing routine, which provides a measure of the reliability of the computed nanoparticle concentrations and ratios. We present simulations and experiments to demonstrate the feasibility of this strategy, which can potentially be utilized for a range of instruments and biomedical applications involving multiplexed SERS nanoparticles.

  14. Synthesis and characterization of silver colloidal nanoparticles with different coatings for SERS application

    Energy Technology Data Exchange (ETDEWEB)

    Mikac, L.; Ivanda, M., E-mail: ivanda@irb.hr [Ruđer Bošković Institute, Laboratory for Molecular Physics (Croatia); Gotić, M. [Ruđer Bošković Institute, Laboratory for Synthesis of New Materials (Croatia); Mihelj, T. [Ruđer Bošković Institute, Laboratory for Synthesis and Processes of Self-assembling of Organic Molecules (Croatia); Horvat, L. [Ruđer Bošković Institute, Laboratory for Electron Microscopy (Croatia)

    2014-12-15

    Silver colloids were produced by chemical reduction of silver salt (silver nitrate, AgNO{sub 3}) solution. As reducing agents, trisodium citrate, sodium borohydride, ascorbic acid, polyvinylpyrrolidone, and glucose were used. The colloids were characterized by UV–Vis, DLS, zeta potential measurements, and SEM. The colloids were stabilized with negative groups or large molecules attached to their surface. The surface-enhanced Raman scattering (SERS) effect of stabilized nanoparticles was measured by using pyridine and rhodamine 6G molecules as analytes and NaNO{sub 3}, KCl, and KBr at different concentrations as aggregating agents. The best Raman signal enhancement was achieved using silver nanoparticles of 40 nm size reduced and stabilized with citrate. The SERS signal of analyte molecules was further enhanced with the addition of sodium borohydride as an alternative aggregating agent. The borohydride had the strongest impact on the SERS effect of the colloid consistent of large (0.5 µm) silver nanoparticles stabilized with aminodextran. The mixture colloid-borohydride-pyridine was stable for hours. The mechanism of borohydride in the colloids is discussed.

  15. Simple synthetic route for SERS-active gold nanoparticles substrate with controlled shape and organization.

    Science.gov (United States)

    Bechelany, Mikhael; Brodard, Pierre; Elias, Jamil; Brioude, Arnaud; Michler, Johann; Philippe, Laetitia

    2010-09-07

    We report a simple synthetic route based on electroless deposition (galvanic displacement) and natural lithography to simultaneously control the shape and organization of Au nanoparticles (NPs). We show for the first time the formation of organized extended domains of Au nanoflowers and nanocrowns with single crystalline tips. The dimension and morphology of the desired nanostructures (NSs) can be tuned easily by controlling the deposition conditions at room temperature using saccharin as an organic additive. The exact role of saccharin on the crystal growth process of Au NPs is also discussed. A systematic surface enhancement Raman spectroscopy (SERS) study of large, ordered areas of organized gold nanoflowers using p-mercaptoaniline (pMA) as the probe molecule shows massive and reproducible enhancements of the Raman signal. By comparing the relative enhancement of the different vibrational modes as a function of the morphology, the specific charge-transfer (chemical effect) SERS mechanism can be distinguished from the general electromagnetic field enhancement (physical effect). A wide range of applications can be envisaged for these SERS substrates.

  16. SENTIDOS DO SER-AÍ-MULHER-APÓS-CIRURGIA-CARDÍACA À LUZ DE HEIDEGGER

    Directory of Open Access Journals (Sweden)

    Thaís Vasconselos Amorim

    2013-01-01

    Full Text Available Estudio cualitativo con objetivo de presentar el descubrimiento de sentidos del ser-mujer-después-cirugía-cardíaca sostenidos por Heidegger. El escenario fue un hospital de alta complejidad cardiovascular en Minas Gerais, Brasil. La fase de campo se produjo en diciembre de 2011 y enero de 2012, y las entrevistadas fueron llevadas a cabo a partir de la pregunta: ¿Cómo es su día a día después de la cirugía? Las lecturas y escuchas de testimonios posibilitaron análisis y interpretación. La mujer aparece en la publicidad, dominada por impersonal, siendo en la charla, curiosidad y ambigüedad. Revela insuficiencia en temor mediado a través del miedo, horror y terror, en dirección a la de-cadencia. Ante los movimientos existenciales, se puede comprender que como ser-en el-mundo, la mujer se escondió en la disposición para el autocuidado, señalando hueco a ser llenado por el enfermero a través de la promoción de la salud que debe aplicarse en su práctica.

  17. SERS and DFT study of copper surfaces coated with corrosion inhibitor

    Directory of Open Access Journals (Sweden)

    Maurizio Muniz-Miranda

    2014-12-01

    Full Text Available Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT approach.

  18. Genetic Association Analysis of Dopamine DRD3 Ser9Gly Polymorphism and Schizophrenia in Malay Population

    Directory of Open Access Journals (Sweden)

    SF Tee

    2011-06-01

    Full Text Available "nBackground: Molecular components of the dopamine receptor (DRD3 play an important role in the pathophysiology of schizophrenia (SCZ. Previous studies have demonstrated an association between the DRD3 Ser9Gly polymorphism and SCZ but the results have been inconclusive. "nMethod: In this study, we investigated this controversial association between the Ser9Gly (A/G polymorphism and SCZ using Malay cases-control (261 cases/157 controls samples. PCR-RFLP was performed to genotype the distribu­tion of the DRD3 Ser9Gly polymorphism."nResults: Both healthy control and SCHZ patient groups were in of Hardy-Weinberg equilibrium for the analyzed ge­netic variability. There was a significant association between the genotype distribution DRD3 polymorphisms and SCZ (χ2= 9.359; df= 2; P= 0.009."nConclusion: We believe that further studies are required to examine the association between others dopamine-related genes and the behavioral phenotypes of SCZ.  

  19. SERS and quantum chemical studies on N-methylglycine molecule on silver nanoparticles

    Science.gov (United States)

    Parameswari, A.; Mohamed Asath, R.; Premkumar, R.; Milton Franklin Benial, A.

    2017-06-01

    Adsorption characteristics of N-methylglycine (Sar) on silver surface was investigated based on density functional theory and surface enhanced Raman spectroscopy (SERS) technique. The Sar was characterized by powder X-ray diffraction (XRD) and dynamic light scattering techniques. AgNPs were prepared by solution combustion method using urea as fuel. The AgNPs were characterized by XRD and high-resolution transmission electron microscopic techniques. The structural parameters of Sar molecule were compared with the reported experimental XRD values. The change in structural parameters of Sar after adsorption on silver surface shows the interaction between Sar and silver cluster. Raman frequencies were calculated for Sar, Sar adsorbed on silver surface and their corresponding spectra were studied experimentally. The conventional Raman and SERS frequencies were compared with the experimental values and analyzed on the basis of potential energy distribution calculation. Natural bond orbital analysis was carried out to investigate the intra-molecular stabilization interactions, which confirms the bioactivity of the molecule. Frontier molecular orbital analysis was carried out for Sar and Sar adsorbed on silver surface. The reduced band gap value was observed for Sar after adsorption on silver surface. The reduction in band gap indicates the intermolecular charge transfer, which leads to the bioactivity of the title molecule. SERS spectral analysis shows that the Sar adsorbed as stand-on orientation on the silver surface.

  20. The application of Silver nanoparticle based SERS in diagnosing thyroid tissue

    Energy Technology Data Exchange (ETDEWEB)

    Huang Zufang; Chen Rong; Chen Guannan; Lin Duo; Xi Gangqin; Chen Yongjian; Lin Hongxin; Lei Jinping [Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, Fujian Normal University, Fuzhou 350007 (China); Li Zuanfang, E-mail: chenr@fjnu.edu.cn [Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350108 (China)

    2011-01-01

    Surface-enhanced Raman scattering (SERS) is proved to be a powerful analytical tool for investigation of biological tissue. In this study, SERS based on Ag nanoparticles was used to investigate the normal and cancerous thyroid tissue. Preliminary results indicated that Raman peaks and the spectra profile from both normal and cancerous tissues showed a basic similarity, obvious differences are that, first, Raman peaks 563cm{sup -1}, 1449cm{sup -1} and 1587cm{sup -1} in cancerous tissue decreased obviously compared with the normal thyroid tissue. Besides, Raman peaks 1004cm{sup -1} and 1128cm{sup -1} might be specific peaks for normal thyroid tissue, whereas 1294cm{sup -1} might attribute to specific peak for cancerous thyroid tissue. In addition, some peaks in normal thyroid tissue appeared to have shifted in cancerous tissue. Intensity ratio of 656cm{sup -1} vs. 725cm{sup -1} in normal tissue are significantly different from cancerous tissue (P<0.005), and it can be a reference for spectroscopic diagnostics of thyroid tissue. This study demonstrates that SERS can be used to monitor the changes at molecular level as well as a complementary tool in thyroid histopathology.

  1. Combined SERS and flow linear dichroism approach to monitoring the interaction of pharmaceuticals with their target

    Science.gov (United States)

    Ianoul, Anatoli I.; Fleury, Fabrice; Duval, Olivier; Jardillier, Jean-Claude; Alix, Alain J.; Nabiev, Igor R.

    1999-04-01

    Surface-Enhanced Raman Scattering (SERS) spectroscopy and Flow Linear Dichroism (FLD) technique have been employed to study the anticancer agent fagaronine and its derivative ethoxidine - double inhibitors of DNA topoisomerases I and II. Cooperative use of two methods permitted (i) to determine the molecular determinants of the drug-DNA interactions; (ii) to monitor in real time the process of topo I inhibition by these anticancer agents. FLD technique allowed us to identify the mode of drug interactions with the DNA as a 'major groove intercalation' and to determine orientation of the drugs chromophores within the complexes. Using SERS spectroscopy we have determined the drugs molecular determinants interacting with the DNA. FLD was also used for real time monitoring of the process of sc DNA relaxation by topo I and of inhibition of relaxation with the pharmaceuticals. Ethoxidine was found to exhibit the same activity of inhibition of sc DNA relaxation as fagaronine at the 10-fold less concentration. The proposed SERS-FLD combined approach demonstrates the new perspectives for screening new pharmaceuticals due to its relative simplicity and low expense, high sensitivity and selectivity, and, finally, possibility of real-time monitoring of the structure-function correlation within the series of drug derivatives.

  2. Estar críticamente enfermo significa no ser capaz y no poder decidir

    Directory of Open Access Journals (Sweden)

    Oscar Beltrán Salazar

    Full Text Available Objetivo: Describir el significado para los pacientes críticamente enfermos hospitalizados en UCI de la experiencia de ser dependientes de los enfermeros para la satisfacción de las necesidades. Metodología: Investigación con enfoque fenomenológico realizada en Medellín en 2006; incluyó a nueve personas adultas entre 24 y 80 años que estuvieron críticamente enfermos y hospitalizados en UCI. La entrevista en profundidad se utilizó para la recolección de información. Los datos se analizaron según el esquema propuesto por Cohen, Kahan y Steeves. Resultados: Depender de otras personas para actuar y para decidir, el sufrimiento y el dolor influyen en la dureza de la experiencia de padecer una enfermedad grave. Discusión: No ser capaz de autosatisfacer las necesidades propias y no poder tomar decisiones contribuyen para que la experiencia de padecer una enfermedad grave sea "dura y difícil". Conclusión: la dependencia de los pacientes que padecen una enfermedad grave no debe ser asumida por los enfermeros sino que debe evaluarse en cada caso, lo mismo que las respuestas a dicha dependencia para asegurar el respeto por los derechos de las personas enfermas.

  3. Hierarchical zwitterionic modification of a SERS substrate enables real-time drug monitoring in blood plasma

    Science.gov (United States)

    Sun, Fang; Hung, Hsiang-Chieh; Sinclair, Andrew; Zhang, Peng; Bai, Tao; Galvan, Daniel David; Jain, Priyesh; Li, Bowen; Jiang, Shaoyi; Yu, Qiuming

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive analytical technique with molecular specificity, making it an ideal candidate for therapeutic drug monitoring (TDM). However, in critical diagnostic media including blood, nonspecific protein adsorption coupled with weak surface affinities and small Raman activities of many analytes hinder the TDM application of SERS. Here we report a hierarchical surface modification strategy, first by coating a gold surface with a self-assembled monolayer (SAM) designed to attract or probe for analytes and then by grafting a non-fouling zwitterionic polymer brush layer to effectively repel protein fouling. We demonstrate how this modification can enable TDM applications by quantitatively and dynamically measuring the concentrations of several analytes--including an anticancer drug (doxorubicin), several TDM-requiring antidepressant and anti-seizure drugs, fructose and blood pH--in undiluted plasma. This hierarchical surface chemistry is widely applicable to many analytes and provides a generalized platform for SERS-based biosensing in complex real-world media.

  4. Phenotype of retinitis pigmentosa associated with the Ser50Thr mutation in the NRL gene.

    Science.gov (United States)

    Bessant, David A R; Holder, Graham E; Fitzke, Frederick W; Payne, Annette M; Bhattacharya, Shomi S; Bird, Alan C

    2003-06-01

    We previously reported an Ser50Thr mutation in the NRL gene as a cause of autosomal dominant retinitis pigmentosa. To determine the characteristic features of the autosomal dominant retinitis pigmentosa phenotype associated with the NRL Ser50Thr mutation in affected individuals from 4 related families. Clinical records were available for 21 affected individuals; 7 underwent more extensive electrophysiologic and psychophysical testing. Night blindness was the first symptom to manifest, with onset between birth and age 16 years. Difficulty with peripheral vision was experienced between 20 and 37 years of age. Visual acuity was well preserved in younger individuals, but those older than 30 years frequently had substantial visual loss (6/36 or worse) associated with macular atrophy. Electrophysiologic testing revealed a nondetectable scotopic electroretinogram with relative preservation of the photopic electroretinogram and pattern electroretinography in the 3 youngest patients tested (aged 15-18 years). In older individuals, all components of the electroretinogram were nondetectable. Dark-adapted visual fields in younger individuals were greatly impaired, but their photopic fields remained relatively well preserved. Older patients had photopic fields limited to just a few degrees. Distinctive peripapillary chorioretinal atrophy seems to develop as the disorder progresses. The NRL Ser50Thr mutation is associated with selective loss of scotopic function before age 20 years. With time, however, the photopic system becomes affected, leading to loss of the photopic visual field and of visual acuity.

  5. Interface between C60 and Ag on nanostructured plasmonic Ag gratings: A SERS study

    Science.gov (United States)

    Khosroabadi, Akram A.; Matz, Dallas L.; Gangopadhyay, Palash; Pemberton, Jeanne E.; Norwood, Robert A.

    2013-09-01

    Nanostructured electrodes and interfaces can enhance light absorption in organic solar cells due to efficient light harvesting. Ultrathin films of an active layer (C60) deposited on nanostructured grating electrodes show more absorption as a result of increased light trapping. Plasmonic nanostructured electrodes with various geometries and dimensions have been fabricated on printed polyacrylonitrile (PAN) and subsequently characterized. Surface enhanced Raman scattering (SERS) measurements show significant signal enhancement (over two orders of magnitude) on nanostructured samples when compared to planar Ag substrates due to local electromagnetic field enhancement. Furthermore, conversion of PAN to graphitic carbon is evidenced in SERS spectra. The surface area was determined using underpotential deposition (UPD) of thallium and agrees with the geometric surface area calculated from SEM images. The FDTD simulated electric field distribution inside the samples confirms the experimental results. A 60 fold increase in the electric field results in three to four orders of magnitude enhancement in the SERS signal depending on the dimensions of the pillars and gratings. Further study of the interaction between a top organic layer (C60) and the Ag electrode will help us to understand the nanoscale charge transfer rate critical to optimization and design of efficient organic solar cells.

  6. One-step Solution Processing of Ag, Au and Pd@MXene Hybrids for SERS

    Science.gov (United States)

    Satheeshkumar, Elumalai; Makaryan, Taron; Melikyan, Armen; Minassian, Hayk; Gogotsi, Yury; Yoshimura, Masahiro

    2016-08-01

    We report on one-step hybridization of silver, gold and palladium nanoparticles from solution onto exfoliated two-dimensional (2D) Ti3C2 titanium carbide (MXene) nanosheets. The produced hybrid materials can be used as substrates for surface-enhanced Raman spectroscopy (SERS). An approximate analytical approach is also developed for the calculation of the surface plasmon resonance (SPR) frequency of nanoparticles immersed in a medium, near the interface of two dielectric media with different dielectric constants. We obtained a good match with the experimental data for SPR wavelengths, 440 nm and 558 nm, respectively for silver and gold nanoparticles. In the case of palladium, our calculated SPR wavelength for the planar geometry was 160 nm, demonstrating that non-spherical palladium nanoparticles coupled with 2D MXene yield a broad, significanlty red-shifted SPR band with a peak at 230 nm. We propose a possible mechanism of the plasmonic hybridization of nanoparticles with MXene. The as-prepared noble metal nanoparticles on MXene show a highly sensitive SERS detection of methylene blue (MB) with calculated enhancement factors on the order of 105. These findings open a pathway for extending visible-range SERS applications of novel 2D hybrid materials in sensors, catalysis, and biomedical applications.

  7. SER Performance of Large Scale OFDM-SDMA Based Cognitive Radio Networks

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    Mostafa Hefnawi

    2014-01-01

    Full Text Available This paper proposes an adaptive large scale multiple input multiple output-beamforming scheme (LSMIMO-BF for uplink (UL access in broadband wireless cognitive networks with multiple primary users (PUs and secondary users (SUs sharing the same spectrum and employing orthogonal frequency-division multiplexing (OFDM. The proposed algorithm seeks the optimal transmit/receive weight vectors that maximize the UL MIMO channel capacity for each cognitive user while controlling the interference levels to PUs. Under the assumption of very large number of antennas at the base station, a closed-form expression for the symbol error rate (SER performance of the cognitive LSMIMO-OFDM system is derived and compared with the one based on conventional beamforming schemes such as MIMO-maximum ratio combining (MIMO-MRC. The analysis and simulation show that when SUs are transmitting with the proposed constrained capacity-aware (CCA scheme, the total interference level at the primary base station is reduced and the SER of PUs is improved compared to the case when the secondary network is using conventional MIMO-MRC. It was also shown that, as the number of base station antennas becomes larger, the constraints imposed by the primary network could be relaxed and the symbol error rate (SER of SUs is improved without harming the PUs performance.

  8. Prominent stylistic aspects in music of Nāser Khosrow's poetry

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    Morteza Mohseni

    2017-04-01

    Full Text Available It is axiomatic  for those who are stylistically a little familiar  about  the periods of  Persian  poetry  that  quasidas  of  Nāser-e Khosrow are totally  different  from  those  of  the  poets  in  fifth  lunar  century  both  in  terms  of  their  contents  and  technically.  This difference  is  seen  even  in  those  areas  of  his  poetry in which the poet is confided to make innovations. This paper investigates Nāser-e Khosrow's style in the field of the music of poetry. It also aims to identify his slylistic differences comparing with those of his most famous contemporaries (Onsori, Farrokhi and Manoochehri in external, lateral and internal areas.      As the first  step, all the Nāser Khosrow's poems -exept for additions section- was considered the Scope of this study, accompanied by main parts of other three cited  poets' divans (poetical works which consists almost 23600 distiches. For the second stage, each poet's divan were separatly scrutinized in three fields of the music of poetry. The frequency of each cases were recorded and after comparing statistics related to Nāser-e Khosrow's poems with other tree poets,  stylistic charachteristics of his poetry were explored. Statistical information related to the poets were generally recorded in a table and some parts of them were shown in a bar graph. It seems necessary to note that the researcher considered two items of  innovation and frequncy in all phases of the study.     Most of the studies done in the field of Nāser-e Khosrow's music of poetry, investigated the prosody and meter of his poetry. Most of these studies considered difficulty and relevancy as the important prosodic characteristics of  his poetry. Regarding the lateral and internal areas of Nāser-e Khosrow's poetry, there are not much argument proposed except for using difficult rhymes and nominal radifs ( for lateral music of poetry and attending to figures of

  9. Detection of Pseudomonas aeruginosa Metabolite Pyocyanin in Water and Saliva by Employing the SERS Technique

    Directory of Open Access Journals (Sweden)

    Olga Žukovskaja

    2017-07-01

    Full Text Available Pyocyanin (PYO is a metabolite specific for Pseudomonas aeruginosa. In the case of immunocompromised patients, it is currently considered a biomarker for life-threating Pseudomonas infections. In the frame of this study it is shown, that PYO can be detected in aqueous solution by employing surface-enhanced Raman spectroscopy (SERS combined with a microfluidic platform. The achieved limit of detection is 0.5 μM. This is ~2 orders of magnitude below the concentration of PYO found in clinical samples. Furthermore, as proof of principle, the SERS detection of PYO in the saliva of three volunteers was also investigated. This body fluid can be collected in a non-invasive manner and is highly chemically complex, making the detection of the target molecule challenging. Nevertheless, PYO was successfully detected in two saliva samples down to 10 μM and in one sample at a concentration of 25 μM. This indicates that the molecules present in saliva do not inhibit the efficient adsorption of PYO on the surface of the employed SERS active substrates.

  10. Acquiring explicit grammatical knowledge using the Spanish verbs ser and estar as examples.

    Science.gov (United States)

    Winitz, Harris; Sagarna, Blanca

    2007-07-01

    The role of explicit and implicit acquisition of grammatical rules in second language learning was examined by assessing high school students performance after several years of study on the correct use of the Spanish verbs ser and estar. These two verbs are essentially equivalent in use to the English verb "to be," but there is a complex set of statements that specifies when each is to be used. A 100-item two-choice test in which students from several different high schools receiving instruction in the explicit principles of these two Spanish verbs or receiving immersion training in which no instruction in their grammatical principles was given were examined for the following five factors: (a) general achievement level, (b) comparison of grade level achievement, (c) time allotted to complete the 100-item test, (d) grammatical instruction prior to taking the 100-item test, and (e) comparison of instructional methodology. The results indicated that students receiving explicit instruction in the rules of ser and estar beyond the first year of study achieved slightly higher scores, but that the level of achievement was considered to be poor. Differences between groups for the remaining factors were not significant. It was concluded that successful application of explicitly learned grammatical rules, such as the rules for ser and estar, may not be achievable in the time frame of a two-year high school foreign language course. Considerations regarding implicit and explicit acquisition of grammatical rules in second language learning were presented.

  11. A Dutch translation of the Self-Efficacy for Rehabilitation Outcome Scale (SER) : a first impression on reliability and validity

    NARCIS (Netherlands)

    Stevens, M; van den Akker-Scheek, [No Value; van Horn, [No Value; Akker-Scheek, I.; van Horn, J.R.

    2005-01-01

    Self-efficacy is a relevant factor during rehabilitation after total hip or knee arthroplasty. Research was done into the reliability and validity of a Dutch translation of the Self-Efficacy for Rehabilitation Outcome Scale (SER). One hundred and forty-one persons filled in the SER questionnaire and

  12. DEVELOPMENT OF SERS SPECTROSCOPY FOR ROUTINE AND RAPID IDENTIFICATION OF ESCHERICHIA COLI AND LISTERIA MONOCYTOGENES ON SILVER COLLOIDAL NANOPARTICLES

    Science.gov (United States)

    SERS spectra were collected to explore its potential for rapid and routine identification of E. coli and L. monocytogenes cultures. Ratios of SERS peaks from K3PO4 were used to evaluate the reproducibility, stability, and binding effectiveness of citrate-reduced silver colloids over batch and storag...

  13. A Dutch translation of the Self-Efficacy for Rehabilitation Outcome Scale (SER) : a first impression on reliability and validity

    NARCIS (Netherlands)

    Stevens, M; van den Akker-Scheek, [No Value; van Horn, [No Value; Akker-Scheek, I.; van Horn, J.R.

    2005-01-01

    Self-efficacy is a relevant factor during rehabilitation after total hip or knee arthroplasty. Research was done into the reliability and validity of a Dutch translation of the Self-Efficacy for Rehabilitation Outcome Scale (SER). One hundred and forty-one persons filled in the SER questionnaire and

  14. Graphene oxide wrapped SERS tags: multifunctional platforms toward optical labeling, photothermal ablation of bacteria, and the monitoring of killing effect.

    Science.gov (United States)

    Lin, Donghai; Qin, Tianqi; Wang, Yunqing; Sun, Xiuyan; Chen, Lingxin

    2014-01-22

    As novel optical nanoprobes, surface-enhanced Raman scattering (SERS) tags have drawn growing interests in the application of biomedical imaging and phototherapies. Herein, we demonstrated a novel in situ synthesis strategy for GO wrapped gold nanocluster SERS tags by using a tris(2,2'-bipyridyl)ruthenium(II) chloride (Rubpy)/GO nanohybrid as a complex Raman reporter, inspired by the role of GO as an artificial receptor for various dyes. The introduction of GO in the synthesis procedure provided systematic solutions for controlling several key parameters of SERS tags, including reproducibility, sensitivity, and colloidal and signal stability. An additional interesting thermal-sensitive SERS property (SERS intensity decreased upon increasing the temperature) was also achieved due to the heat-induced release/redistribution of reporter molecules adsorbed on GO. Combining the synergic effect of these features, we further fabricated multifunctional, aldehyde group conjugated Au@Rubpy/GO SERS tags for optical labeling and photothermal ablation of bacteria. Sensitive Raman imaging of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria could be realized, and satisfactory photothermal killing efficacy for both bacteria was achieved. Our results also demonstrated the correlation among the SERS intensity decrease ratio, bacteria survival rate, and the terminal temperature of the tag-bacteria suspension, showing the possibility to use SERS assay to measure antibacterial response during the photothermal process using this tag.

  15. Surface-enhanced Raman spectroscopy (SERS) for identifying traces of adenine in different mineral and rock samples

    Science.gov (United States)

    Lafuente, B.; Navarro, R.; Sansano, A.; Rull, F.

    2012-09-01

    The aim of this study is to analyze the potentials of SERS as a technique for in-situ identification of life traces in Mars surface explorations using the Raman instrument (RLS), payload of the ESA Mars mission Exomars. This preliminary study focused on detection of adenine on a variety of rocks soils samples using macro-SERS detection.

  16. Endurecimiento superficial de aceros y fundiciones mediante láser de Nd: YAG

    Directory of Open Access Journals (Sweden)

    Sagaró, R.

    2001-10-01

    Full Text Available This work relates with heat treatment by laser of metallic surfaces. The hardening of steels AISI 1045, W1, W112 and flake and nodular cast irons was carried out using a Nd: YAG laser. Operation parameters of laser like beam power (P and traverse speed of the laser Spot (V are closely related to the depth of hardening. The authors present some analyses on metallographic studies. In all cases Vickers microhardness valves of about 500-900 HV (three or four times higher than original substrates. Relations between microhardness and depth of hardening are presented for the processed materials. Experimental results showed that the scan speed increase produces a decrease on depth of hardening as reported by others researchers. On the other hand, the samples with higher carbon content show lower hardenining depth. In addition, tribological tests were carried out. These tests show wear resistance when compared with conventional heat treatment. The frictional coefficient decrease in the samples with laser surface treatment.

    En el trabajo se presentan los resultados del tratamiento térmico superficial, con técnica láser, de superficies metálicas. Con el empleo de un láser de Nd:YAG se procedió al endurecimiento superficial de los aceros AISI 1045, W1, W112 y fundiciones de tipo laminar y nodular. Se presentan los resultados del tratamiento térmico superficial atendiendo al parámetro velocidad de barrido del haz de láser (V. De igual forma se estudian las microestructuras metalográficas obtenidas. En todos los casos, se obtienen valores de microdureza Vickers que oscilan entre los 500-900 HV (incrementos de tres-cuatro veces respecto al material base. Los resultados obtenidos permiten afirmar que, en todos los casos estudiados, el incremento de la velocidad de barrido provocó una disminución de la profundidad de la capa endurecida, en correspondencia con otros resultados expuestos en la literatura especializada. Las experiencias del

  17. SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure.

    Science.gov (United States)

    Zhang, C; Jiang, S Z; Huo, Y Y; Liu, A H; Xu, S C; Liu, X Y; Sun, Z C; Xu, Y Y; Li, Z; Man, B Y

    2015-09-21

    We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

  18. A green, reusable SERS film with high sensitivity for in-situ detection of thiram in apple juice

    Science.gov (United States)

    Sun, Hongbao; Liu, Hai; Wu, Yiyong

    2017-09-01

    We report a green and reusable surface-enhanced Raman scattering (SERS) film based on PMMA/Ag NPs/graphene. By using this Raman substrate, the SERS signals of R6G were significantly enhanced reaching a minimum detectable concentration of 5 × 10-8 M, due to having lots of hot spots adhered backside to the exposed graphene. The SERS film can be used for in-situ monitoring of trace thiram in apple juice with a detection limit of 1 × 10-6 M (0.24 ppm), which is below the maximal residue limit (MRL) of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency (EPA). Furthermore, reusability studies show that the SERS film can be used repeatedly. In addition, the graphene-enhanced SERS technique shows great potential applications for the in-situ detection and identification of pesticide residues in environmental water, fruits and vegetables.

  19. Ser humano idoso estomizado e ambientes de cuidado: reflexão sob a ótica da complexidade

    Directory of Open Access Journals (Sweden)

    Edaiane Joana Lima Barros

    2012-10-01

    Full Text Available Trata-se de discussão acerca da relação ser humano idoso estomizado e seus ambientes de cuidado sob o olhar da Complexidade de Edgar Morin. Um eixo sustenta a reflexão: ambientes de cuidado para o ser humano idoso com estomia. Nesse sentido, apresentam-se três tipos de ambiente que circundam o contexto de estomização do ser humano idoso: ambiente domiciliar, ambiente grupal e ambiente hospitalar. A reflexão traz como contribuição social um novo olhar acerca do redimensionamento do cuidado ao ser humano idoso estomizado em seu ambiente. Considera-se que o ambiente que abriga esse ser humano comporta uma diversidade de sentimentos, emoções, experiências, vincula múltiplos significados da relação do ambiente e o processo de cuidado a partir da Complexidade.

  20. Impact of temperature-induced coalescence on SERS properties of Au nanoparticles deposited on GaN nano-columns

    Science.gov (United States)

    Dzięcielewski, Igor; Smalc-Koziorowska, Julita; Bańkowska, Małgorzata; Sochacki, Tomasz; Khachapuridze, Alexandr; Weyher, Jan

    2016-08-01

    Nanostructured GaN surfaces sputtered with Au provide very promising and reproducible platforms for surface enhanced Raman scattering (SERS). The enhancement factor (EF) in SERS is expected to depend strongly on the local metal (Au) surface structure (size, distribution and morphology). Herein we show how temperature-induced coalescence followed by recrystallization of Au on GaN nano-columns occurs well below the melting point of gold. This process is reflected in SEM, TEM images and SERS spectra of Au/GaN - bound p-mercaptobenzoic acid (4-MBA), a model Raman scatterer. SERS signals of 4-MBA bound to Au/GaN reach minimum for platforms exposed to t = 350 °C before regaining the intensity when annealed in the range of 450-900 °C. The results have been discussed in the light of the nature of SERS active sites - so called "hot spots" and structure of Au nanoparticles.

  1. Ser respetuoso es ser persona. El niño y la pedagogía moral de los nahuas del centro de México

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    Lorente Fernández, David

    2012-12-01

    Full Text Available Inside informal education, the teaching of respect results decisive for Central Mexico indigenous nahua. The respect is the moral value through which a human being becomes a «person». This pedagogical process has been barely studied and has not been solved how children grabs this important tool to conduce themselves among the family and the community life. Based on an extended fieldwork performed on the Texcoco Sierra area, located close to Mexico City, in which the more common adscription features, as the indigenous language and dress has disappeared due the modernization process, this article shows that respect constitutes a solid base to preserve ethnic identity. Children are educated through oral tales and the participation on a vast array of activities on the daily life. Despite the fact to be under «mestizo» respect, which is taught on schools, the nahua morality exists among the children as «granted» and constitutes the lifestyle of the Sierra.

    En el seno de la educación informal, la transmisión infantil del respeto resulta determinante para los indígenas nahuas del centro de México. El respeto es el valor moral principal que permite convertir a un ser humano en «persona». Sin embargo, este proceso pedagógico ha sido escasamente analizado y en gran parte continúa siendo un enigma cómo los niños adquieren lo que representa su más valiosa herramienta para conducirse adecuadamente en la vida familiar y comunitaria. Basándome en un prolongado trabajo de campo realizado en la región de la Sierra de Texcoco, cercana a la Ciudad de México, en la que los rasgos de autoascripción más convencionales, como el idioma indígena y la vestimenta tradicional, han desaparecido por los embates de los procesos de modernización, el artículo demuestra que inculcar el respeto constituye una sólida base para la conservación de la identidad étnica. Los niños son educados con relatos orales y mediante su participación en las

  2. Compreendendo o ser da pessoa com câncer: suas posturas e possibilidades existenciais

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    Karina Machado Siqueira

    2008-09-01

    Full Text Available O número expressivo de pessoas que buscam as instituições de saúde para o tratamento do câncer nos leva a assumir uma postura reflexiva em relação à forma com que vêm sendo cuidadas pelos profissionais de saúde. O desenvolvimento deste estudo teve como propósito desvelar o significado de ser-com-câncer para pacientes oncológicos, buscando compreendê-los nesse vivenciar e vislumbrando a descoberta de novos caminhos para o cuidado a essas pessoas. Sustentando-me no entendimento de que somente as pessoas que experimentam a situação de adoecer com câncer são capazes de transmitir o sentido e o significado do que estão vivendo, optei pela metodologia da pesquisa qualitativa – modalidade fenomenológica, baseada no referencial filosófico de Edmund Husserl. Foram realizadas entrevistas junto a onze pacientes internados em uma instituição de saúde especializada no tratamento do câncer, localizada em Goiânia – GO. Todos os pacientes eram adultos e estavam conscientes do diagnóstico. Apropriei-me de algumas idéias da ontologia existencial de Martin Heidegger para melhor desenvolver a análise dos dados. Pude apreender que o câncer mostra-se ao Ser que vive essa situação de doença como uma experiência difícil, saturada de sofrimento e dor. O recebimento do diagnóstico revelou-se como um dos piores momentos para o paciente, quando vivencia, dentre outros sentimentos, a angústia diante do desconhecido e o medo da morte. Ao aproximar-me do mundo-vida dessas pessoas, percebi o quanto o câncer, enquanto realidade na vida do Ser, pode afetar tanto sua autopercepção e seu comportamento, quanto suas relações sociais. A partir do momento em que o Ser se depara com a realidade de existir com uma doença grave, diversos projetos existenciais tendem a ser anulados ou modificados pela situação vivida. Ao se depararem com a necessidade de conviver com um problema de saúde grave, as pessoas buscam, em muitos casos, formas de

  3. Nanostructured SERS substrates produced by nanosphere lithography and plastic deformation through direct peel-off on soft matter

    Science.gov (United States)

    Wang, Tzyy-Jiann; Hsu, Kai-Chieh; Liu, Yi-Cheng; Lai, Chih-Hsien; Chiang, Hai-Pang

    2016-05-01

    We present a novel fragmented-film surface-enhanced Raman scattering (SERS) substrate produced by nanosphere lithography and direct peel-off for SERS efficacy enhancement. The 2D hexagonally close-packed polystyrene nanospheres on the polydimethylsilozane (PDMS) substrate are covered with silver film and then directly peeled off using sticky tape. During the peel-off process, the pulling force induces the stretch and contraction of the PDMS substrate and causes fracture of the 2D triangular silver film. Under laser excitation, a stronger localized electric field is induced in the smaller cracks and enhances the SERS intensity. The origin of this SERS enhancement is confirmed by numerical simulation using the finite element method and substrate annealing to smoothen the cracks. For the case using nanospheres with a diameter of 740 nm, an enhancement factor 6.5 × 106 can be achieved. The proposed fragmented-film SERS substrate gains 1.8 and 2.6 times larger Raman intensity at the 1358 cm-1 SERS peak than those using pyramidal silver islands and silver nanoshell array. The proposed SERS substrate has the features of easy fabrication, low production cost, short fabrication time and high enhancement factor.

  4. A novel paper rag as 'D-SERS' substrate for detection of pesticide residues at various peels.

    Science.gov (United States)

    Zhu, Yiqun; Li, Minqiang; Yu, Daoyang; Yang, Liangbao

    2014-10-01

    Many important considerations in the design of practical Surface enhanced Raman spectroscopy (SERS) substrates are necessary, such as the low cost, simple preparation, mass production and high efficiency of sample collection, which the conventional rigid substrates are lack of. In this work, practical SERS substrates based on deposition of silver nanoparticles (Ag NPs) on commercially available low-cost filter paper were prepared by simple silver mirror reaction in a large scale, and utilized for rapid, portable and accurate identification and detection of pesticide residues at various peels. Compared with conventional substrates, this novel SERS substrate dramatically enhanced the sample collection efficiency by simply swabbing paper-based device across different surfaces without destroying the sample, meanwhile avoiding the substrate signal of real-world samples. Considering their low cost, portability, simplicity and high sample collection efficiency, Ag NP-decorated filter paper, as practical SERS substrate, are used in solving critical problems for detection of pesticide residues at various peels. SERS experiments were carried out on Ag NP-decorated filter paper combined with 'dynamic SERS' (D-SERS) due to its high detection sensitivity. The excellent detection performance of the Ag NP-based filter paper was demonstrated by detection thiram and paraoxon residues at various peels. Besides, the stability and reproducibility of the practical substrates were also involved.

  5. A surface-enhanced Raman scattering (SERS-active optical fiber sensor based on a three-dimensional sensing layer

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    Chunyu Liu

    2014-08-01

    Full Text Available To fabricate a new surface-enhanced Raman scattering (SERS-active optical fiber sensor, the design and preparation of SERS-active sensing layer is one of important topics. In this study, we fabricated a highly sensitive three-dimensional (3D SERS-active sensing layer on the optical fiber terminal via in situ polymerizing a porous polymer material on a flat optical fiber terminal through thermal-induced process, following with the photochemical silver nanoparticles growth. The polymerized polymer formed a 3D porous structure with the pore size of 0.29–0.81 μm, which were afterward decorated with abundant silver nanoparticles with the size of about 100 nm, allowing for higher SERS enhancement. This SERS-active optical fiber sensor was applied for the determination of 4-mercaptopyridine, crystal violet and maleic acid The enhancement factor of this SERS sensing layer can be reached as about 108. The optical fiber sensor with high sensitive SERS-active porous polymer is expected for online analysis and environment detection.

  6. Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals

    Science.gov (United States)

    Wu, Wei; Liu, Li; Dai, Zhigao; Liu, Juhua; Yang, Shuanglei; Zhou, Li; Xiao, Xiangheng; Jiang, Changzhong; Roy, Vellaisamy A. L.

    2015-05-01

    Ideal SERS substrates for sensing applications should exhibit strong signal enhancement, generate a reproducible and uniform response, and should be able to fabricate in large-scale and low-cost. Herein, we demonstrate low-cost, highly sensitive, disposable and reproducible SERS substrates by means of screen printing Ag nanoparticles (NPs) on a plastic PET (Polyethylene terephthalate) substrates. While there are many complex methods for the fabrication of SERS substrates, screen printing is suitable for large-area fabrication and overcomes the uneven radial distribution. Using as-printed Ag substrates as the SERS platform, detection of various commonly known chemicals have been done. The SERS detection limit of Rhodamine 6G (R6G) is higher than the concentration of 1 × 10-10 M. The relative standard deviation (RSD) value for 784 points on the detection of R6G and Malachite green (MG) is less than 20% revealing a homogeneous SERS distribution and high reproducibility. Moreover, melamine (MA) is detected in fresh liquid-milk without additional pretreatment, which may accelerate the application of rapid on-line detection of MA in liquid milk. Our screen printing method highlights the use of large-scale printing strategies for the fabrication of well-defined functional nanostructures with applications well beyond the field of SERS sensing.

  7. Raman and SERS study on atrazine, prometryn and simetryn triazine herbicides

    Science.gov (United States)

    Bonora, Sergio; Benassi, Enrico; Maris, Assimo; Tugnoli, Vitaliano; Ottani, Stefano; Di Foggia, Michele

    2013-05-01

    In the present study, we considered the Raman spectra of atrazine, prometryn and simetryn, in the solid form and in polar and apolar solvents, extending the investigation in the very diluted aqueous solutions (ppm) range by using the SERS technique. We performed theoretical calculations at the B3LYP/aug-cc-pVQZ level on the three triazines, alone and in solution with polar and apolar solvents. An excellent agreement between theoretical and experimental frequencies was reached, with differences lying within few wavenumbers. The small differences observed can be ascribed to the solid crystalline phase and can be caused by local deviations in the uniformity of the crystalline field or to a coupling with lattice vibrations. Also the theoretical and experimental peak intensities well agreed and in most cases lied within ±10%, the differences being ascribed to the local non-homogeneity of dielectric properties in the crystal. Moreover, this behavior confirmed the rigidity of the molecules and that their structure was not involved during the solution process. The theoretical SERS spectra at B3LYP/6-311+G(d,p) level of triazines bound to an Ag2 metal cluster offered an acceptable qualitative agreement with the experimental ones, suggesting that the stronger interaction site of triazines with Ag2 was on the less sterical hindered aromatic nitrogen atom, namely forming the N6⋯Ag2 molecular complex with atrazine, and the N2⋯Ag2 or N4⋯Ag2 molecular complexes with simetryn and prometryn. The agreement between calculated and experimental SERS spectra was not as good as that observed for the Raman spectra of pure compounds, but the trend of the theoretical spectra offered a useful guideline for the comprehension of the interaction sites and of the structural modification after adsorption on silver particles.

  8. Nanostructured SERS-electrochemical biosensors for testing of anticancer drug interactions with DNA.

    Science.gov (United States)

    Ilkhani, Hoda; Hughes, Taylor; Li, Jing; Zhong, Chuan Jian; Hepel, Maria

    2016-06-15

    Widely used anti-cancer treatments involving chemotherapeutic drugs result in cancer cell damage due to their strong interaction with DNA. In this work, we have developed laboratory biosensors for screening chemotherapeutic drugs and to aid in the assessment of DNA modification/damage caused by these drugs. The sensors utilize surface-enhanced Raman scattering (SERS) spectroscopy and electrochemical methods to monitor sensory film modification and observe the drug-DNA reactivity. The self-assembled monolayer protected gold-disk electrode (AuDE) was coated with a reduced graphene oxide (rGO), decorated with plasmonic gold-coated Fe2Ni@Au magnetic nanoparticles functionalized with double-stranded DNA (dsDNA), a sequence of the breast cancer gene BRCA1. The nanobiosensors AuDE/SAM/rGO/Fe2Ni@Au/dsDNA were then subjected to the action of a model chemotherapeutic drug, doxorubicin (DOX), to assess the DNA modification and its dose dependence. The designed novel nanobiosensors offer SERS/electrochemical transduction, enabling chemically specific and highly sensitive analytical signals generation. The SERS measurements have corroborated the DOX intercalation into the DNA duplex whereas the electrochemical scans have indicated that the DNA modification by DOX proceeds in a concentration dependent manner, with limit of detection LOD=8 µg/mL (S/N=3), with semilog linearity over 3 orders of magnitude. These new biosensors are sensitive to agents that interact with DNA and facilitate the analysis of functional groups for determination of the binding mode. The proposed nanobiosensors can be applied in the first stage of the drug development for testing the interactions of new drugs with DNA before the drug efficacy can be assessed in more expensive testing in vitro and in vivo.

  9. La determinación retórica del ser

    Directory of Open Access Journals (Sweden)

    Álvaro Vallejo Campos

    2014-05-01

    Full Text Available En el presente trabajo se pretende reflexionar sobre la ontología del discurso utópico platónico en la República. Platón opone la figura del filósofo gobernante, que es de quien depende que el proyecto sea realizable, a «los amantes de los espectáculos» y a «los hombres de acción». Todas estas figuras, que pertenecen a la sofística y la retórica, son en realidad «amantes de la opinión», de manera que la demarcación del verdadero filósofo supone defender contra estos una idea del arte de gobernar basada en la epistḗmē y en una concepción normativa del ser. De los diversos sentidos que tiene el ser en la ontología platónica, existencial, predicativo y veritativo, el proyecto platónico del arte de gobernar se fundamenta en una concepción normativa del ser, cuya perfección esencial no viene determinada por la nuda existencia, sino por la identidad y la unidad de la forma. La ontología platónica así definida, en unos términos que vienen determinados en gran medida por su discusión con la retórica, se convierte en el fundamento del paradigma para la construcción de la ciudad ideal, cuya validez no está condicionada por la existencia empírica de las cosas.

  10. Outra mente que ser: revolvendo questões à luz da pedagogia do oprimido

    Directory of Open Access Journals (Sweden)

    Lovison, Aida Maria

    2008-01-01

    Full Text Available Neste texto, a ética da alteridade de Emmanuel Levinas, para quem a nudez do rosto não é uma figura de estilo, mas a consciência moral, encontra a teoria da ação (cultural dialógica, fundamento, na pedagogia do oprimido de Paulo Freire, de sua denúncia-anúncio contra a desumanização e a opressão. Para ambos, a violência toma o sentido de posse, modo pelo qual um ente, embora existindo, é parcialmente negado. Essa parcialidade, ao negar a independência do ente, instaura a opressão, negando ao oprimido a sua vocação de ser mais. A opressão mata a vida. Contudo, é pela tomada de consciência desta condição de ser-para-outro, que a própria possibilidade do humano pode ser pensada, porque a relação com outrem ou com a coletividade é nossa relação, irredutível à compreensão. Reconhecer tal subversão, ou seja, que os oprimidos, na medida em que se libertam, eles evitam a volta ao regime opressor e, ao fazê-lo, libertam o opressor, eles inauguram o amor não é assumir, em essência, que ética é a construção do sentido da vida humana desde o encontro com o outro?

  11. Biocompatible 3D SERS substrate for trace detection of amino acids and melamine.

    Science.gov (United States)

    Satheeshkumar, Elumalai; Karuppaiya, Palaniyandi; Sivashanmugan, Kundan; Chao, Wei-Ting; Tsay, Hsin-Sheng; Yoshimura, Masahiro

    2017-03-21

    A novel, low-cost and biocompatible three-dimensional (3D) substrate for surface-enhanced Raman spectroscopy (SERS) is fabricated using gold nanoparticles (AuNPs) loaded on cellulose paper for detection of amino acids and melamine. Dysosma pleiantha rhizome (Dp-Rhi) capped AuNPs (Dp-Rhi_AuNPs) were prepared by in situ using aqueous extract of Dp-Rhi and in situ functionalized Dp-Rhi on AuNPs surface was verified by Fourier transform infrared spectroscopy and zeta potentials analysis shows a negative (-18.4mV) surface charges, which confirm that presence of Dp-Rhi on AuNPs. The biocompatibility of Dp-Rhi_AuNPs is also examined by cell viability of FaDu cells using MTS assay and compared to control group. In conclusion, the SERS performance of AuNPs@cellulose paper substrates were systematically demonstrated and examined with different excitation wavelengths (i.e. 532, 632.8 and 785nm lasers) and the as-prepared 3D substrates provided an enhancement factor approaching 7 orders of magnitude compared with conventional Raman intensity using para-nitrothiophenol (p-NTP), para-aminothiophenol (p-ATP) and para-mercaptobenzoic acid (p-MBA) as probe molecules. The strong electromagnetic effect was generated at the interface of AuNPs and pre-treated roughened cellulose paper is also investigated by simulation in which the formation of possible Raman hot-spot zone in fiber-like microstructure of cellulose paper decorated with AuNPs. Notably, with optimized condition of as-prepared 3D AuNPs@cellulose paper is highly sensitive in the SERS detection of aqueous tyrosine (10(-10)M) and melamine (10(-9)M).

  12. [NIR-SERS Spectra Detection of Cytidine on Nano-Silver Films].

    Science.gov (United States)

    Zhang, De-qing; Liu, Ren-ming; Zhang, Guo-qiang; Zhang, Yan; Xiong, Yang; Zhang, Chuan-yun; Li, Lun; Si, Min-zhen

    2016-03-01

    The polyvinyl alcohol (PVA) protected silver glass-like nanostructure (PVA-Ag-GNS) with high surface-enhanced Raman scattering (SERS) activity was prepared and employed to detect the near-infrared surface enhanced Raman scattering (NIR-SERS) spectra of cytidine aqueous solution (10(-2)-10(-8) mol x L(-1)). In the work, the near-infrared laser beam (785 nm) was used as the excitation light source. The experiment results show that high-quality NIR-SERS spectra were obtained in the ranges of 300 to 2 000 cm(-1) and the detection limit of cytidine aqueous solution was down to 10(-7) mol x L(-1). Meanwhile, the PVA-Ag-GNS shows a high enhancement factor (EF) of -10(8). In order to test the optical reproducibility of PVA-Ag-GNS, ten samples of cytidine aqueous solution (10(-2)-10(-5) mol x L(-1)) had been dropped onto the surface of PVA-Ag-GNS respectively. Meanwhile, these samples were measured by the portable Raman spectrometer. As a result, the PVA-Ag-GNS demonstrated good optical reproducibility in the detection of cytidine aqueous solution. In addition, to explain the reason of enhancement effect, the ultraviolet-visible (UV-Vis) extinction spectrum and scanning electron microscope (SEM) of cytidine molecules adsorbed on the surface of PVA-Ag-GNS were measured. There is plasmon resonance band at 800 nm in the UV-Vis extinction Spectrum of the compound system. Therefore, when the near-infrared laser beam (785 nm) was used as excitation light source, the compound system may produce strongly surface plasmon resonance (SPR). According to the SEM of PVA-Ag-GNS, there are much interstitial between the silver nanoparticles. So NIR-SERS is mainly attributed to electromagnetic (EM) fields associated with strong surface plasmon resonance. At last, the geometry optimization and pre-Raman spectrum of cytidine for the ground states were performed with DFT, B3LYP functional and the 6-311G basis set, and the near-infrared laser with wavelength of 785 nm was employed in the pre

  13. Conformational SERS Classification of K-Ras Point Mutations for Cancer Diagnostics.

    Science.gov (United States)

    Morla-Folch, Judit; Gisbert-Quilis, Patricia; Masetti, Matteo; Garcia-Rico, Eduardo; Alvarez-Puebla, Ramon A; Guerrini, Luca

    2017-02-20

    Point mutations in Ras oncogenes are routinely screened for diagnostics and treatment of tumors (especially in colorectal cancer). Here, we develop an optical approach based on direct SERS coupled with chemometrics for the study of the specific conformations that single-point mutations impose on a relatively large fragment of the K-Ras gene (141 nucleobases). Results obtained offer the unambiguous classification of different mutations providing a potentially useful insight for diagnostics and treatment of cancer in a sensitive, fast, direct and inexpensive manner.

  14. IMPORTANCIA DE LA MUSICOTERAPIA EN EL ÁREA EMOCIONAL DEL SER HUMANO

    Directory of Open Access Journals (Sweden)

    Serafina Poch Blasco

    2001-01-01

    Full Text Available La Musicoterapia científica es una técnica terapéutica de plena actualidad, cuyo interés crece progresivamente. Las carencias en el área de la educación emocional de niños y adolescentes podrían paliarse con programas de Musicoterapia en los centros educativos, ya que la salud emocional es fundamental para el ser humano, sin la cual todo lo demás cae por su base. Se exponen dos programas: uno de Musicoterapia Preventiva y otro de Ayuda a niños de preescolar, con problemas, hijos de padres separados.

  15. Detection of protease and protease activity using a single nanoscrescent SERS probe

    Science.gov (United States)

    Liu, Gang L.; Ellman, Jonathan A.; Lee, Luke P.; Chen, Fanqing Frank

    2013-01-29

    This invention pertains to the in vitro detection of proteases using a single peptide-conjugate nanocrescent surface enhanced Raman scattering (SERS) probes with at least nanomolar sensitivity. The probe enables detection of proteolytic activity in extremely small volume and at low concentration. In certain embodiments the probes comprise an indicator for the detection of an active protease, where the indicator comprises a nanocrescent attached to a peptide, where said peptide comprises a recognition site for the protease and a Raman tag attached to the peptide.

  16. Silver nanoparticles deposited on porous silicon as a surface-enhanced Raman scattering (SERS) active substrate.

    Science.gov (United States)

    Zeiri, Leila; Rechav, Katya; Porat, Ze'ev; Zeiri, Yehuda

    2012-03-01

    Silver nanoparticles were deposited spontaneously from their aqueous solution on a porous silicon (PS) layer. The PS acts both as a reducing agent and as the substrate on which the nanoparticles nucleate. At higher silver ion concentrations, layers of nanoparticle aggregates were formed on the PS surface. The morphology of the metallic layers and their SERS activity were influenced by the concentrations of the silver ion solutions used for deposition. Raman measurements of rhodamine 6G (R6G) and crystal violet (CV) adsorbed on these surfaces showed remarkable enhancement of up to about 10 orders of magnitude.

  17. SENTIDOS DO SER-AÍ-MULHER-APÓS-CIRURGIA-CARDÍACA À LUZ DE HEIDEGGER

    OpenAIRE

    Thaís Vasconselos Amorim; Anna Maria de Oliveira Salimena; Maria Carmen Simões Cardoso de Melo; Ívis Emília de Oliveira Souza; Lúcia de Fátima da Silva

    2013-01-01

    Estudio cualitativo con objetivo de presentar el descubrimiento de sentidos del ser-mujer-después-cirugía-cardíaca sostenidos por Heidegger. El escenario fue un hospital de alta complejidad cardiovascular en Minas Gerais, Brasil. La fase de campo se produjo en diciembre de 2011 y enero de 2012, y las entrevistadas fueron llevadas a cabo a partir de la pregunta: ¿Cómo es su día a día después de la cirugía? Las lecturas y escuchas de testimonios posibilitaron análisis y interpretación. La mujer...

  18. De la identidad del ser a la pedagogía de la diferencia

    OpenAIRE

    Ignacio Calderón Almendros; Juan Miguel Calderón Almendros; María Teresa Rascón Gómez

    2016-01-01

    Las distintas definiciones acerca del ser humano intentan identificar una característica que generalizar para todo el género Homo. Esta cuestión nace del principio de identidad, y tiene fuertes repercusiones en las concepciones antropológicas sobre las que se asienta la pedagogía. El cuestionamiento de este principio permitiría dar cabida al conflicto en el discurso pedagógico, así como poner en crisis algunas de las bases sobre las que asentamos el análisis de la diversidad y su atención edu...

  19. La experiencia de ser cuidadora de un anciano con enfermedad crónica

    OpenAIRE

    Gabriela Aldana-González; Liliana García-Gómez

    2011-01-01

    Objetivo: conocer la construcción de la experiencia de ser cuidador de un anciano con enfermedad crónico-degenerativa en mujeres de San Cristóbal Ecatepec, México. Método: investigación de corte cualitativo, con cuatro personas de sexo femenino todas ellas cuidadoras de ancianos con enfermedades crónico-degenerativas. Se utilizó la entrevista a profundidad como técnica para la recolección de datos. Los datos se analizaron a partir de ubicar categorías de análisis desde una orientación fenomen...

  20. O significado de ser familiar cuidador do portador de transtorno mental

    OpenAIRE

    Marília Mazzuco Sant'Ana; Valdete Preve Pereira; Miriam Süsskind Borenstein; Alcione Leite da Silva

    2011-01-01

    Este es un estudio cualitativo de enfoque exploratorio, descriptivo, cuyo objetivo fue comprender el significado de ser un cuidador familiar de pacientes con trastornos mentales. El estudio se desarrolló con los familiares de los pacientes con trastornos mentales, seguido en la clinica integrada de Atención Primaria de Salud en el municipio de Biguaçu-SC, vinculada a Universidade do Vale do Itajaí. Los datos cualitativos fueron obtenidos por entrevista dialógica y analizados sobre la base de ...

  1. Investigation of the catalysis and SERS properties of flower-like and hierarchical silver microcrystals

    Science.gov (United States)

    Yang, Jianhui; Cao, Beibei; Li, Huiqin; Liu, Bin

    2014-10-01

    Noble metal nano/microstructures have attracted considerable attention because of their unique properties and their various applications. Controlling the shape of noble metal nano/microstructures is a promising strategy to tailor their physical and chemical properties for various applications in fields such as biological labeling and imaging, catalysis, and sensing. Among various specific structures, flower-like and hierarchical silver nano/microstructures have attracted increasing interest because exploration of these novel nano/microstructures with unusual optical properties can provide new perspectives into the rational design of novel materials. It is significantly more challenging to develop facile and effective solution approaches for systematic manipulation of the shape of Ag nano/microstructures. In this article, we revisited the ascorbic acid reduction method to prepare flower-like silver microcrystal with plate petals and hierarchical Ag microcrystal on a large scale and in high purity. Ascorbic acid plays two roles of a reducing agent and a crystal growth regulator. Therefore, the molar ratio of ascorbic acid and silver nitrate is critical to the formation of Ag microcrystal. The controlling of the two different Ag microstructures can be achieved by adjusting the molar ratio of the reactants in aqueous medium at room temperature. The as-prepared Ag microcrystals were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The flower-like Ag microcrystal with plate petals and hierarchical Ag microcrystal with nanoscale sharp tips and gaps could exhibit high catalytic activity and strong surface-enhanced Raman spectroscopy (SERS) activity due to the high surface area and the local electromagnetic field intensity enhancement, respectively. The potential application of the as-prepared Ag microcrystals in catalysis and SERS was investigated, which revealed that these two kinds of Ag microcrystals exhibit high

  2. Cambios dimensionales que sufren los emergentes maquinados de titanio al ser personalizados con porcelana para titanio.

    OpenAIRE

    Martin, Alberto José

    2012-01-01

    Introducción: En implantología oral, la falta de adaptación marginal entre el implante y el emergente, favorece la aparición de periimplantitis. Los mejores resultados se han obtenido con la utilización de emergentes maquinados de titanio, pero al ser metálicos, ante la presencia de encía marginal tipo 1, da una coloración oscura, debido al fino espesor que la caracteriza. Con el fin de evitar la traslucidez del metal, es viable la personalización del emergente, con porcelana para titanio; da...

  3. ¿Puede ser imperfecto el pretérito perfecto?

    OpenAIRE

    Moreno de Alba, José G.; Universidad Nacional Autónoma de México

    2013-01-01

    Se ha señalado, para un dialecto del español (el mexicano) que la peculiaridad distintiva del perfecto compuesto es ser imperfecto: "la forma compuesta expresa acciones durativas e imperfectas; fenómenos que, aunque iniciados en el pasado, se continuan hacia el futuro". Recientemente esta aseveración no sólo ha sido duramente criticada sino vista como producto de una "confusión de conceptos". Para eliminar esa confusión, se recomienda tener en cuenta lo que, según el crítico, es la perfección...

  4. Análisis de formulación del programa “Ser Pilo Paga”

    OpenAIRE

    Castro Rojas, Valentina

    2016-01-01

    El presente artículo busca analizar la formulación del programa “Ser Pilo Paga” (SPP) que hace parte de la política Nacional de educación superior. Para esto, se hará referencia a los conceptos de política pública y su ciclo, enfocándonos en la fase de formulación, para luego explicar las generalidades de la educación superior en Colombia. Asimismo se estudia en detalle, la base y el fundamento, al igual que la normatividad, y componentes del programa. Mediante el análisis de estos conceptos,...

  5. La relaciòn interpersonal en el ser y quehacer de enfermerìa

    OpenAIRE

    Torres Pique, Ana María; Pontificia Universidad Javeriana

    2011-01-01

    Este artículo presenta algunos elementos sobre los avances logrados en el trabajo de varios años de la Facultad de Enfermería de la Pontificia Universidad Javeriana, que se aproximan a la construcción del ser y quehacer del profesional de Enfermería. Inicialmente, y a manera de ubicación, se abordan los requisitos para una disciplina y práctica, porque, desde allí, se analizan algunos aspectos fundamentales como la relación interpersonal y el cuidado de enfermería, ejes de la profesión. Final...

  6. Será que os extraterrestres percebem matemática?

    OpenAIRE

    Teixeira, Ricardo Emanuel Cunha

    2013-01-01

    (...) Se existisse vida noutro planeta, e se os seres desse planeta tentassem comunicar connosco, que tipo de mensagem receberíamos? Por outro lado, se quiséssemos enviar uma mensagem para esse planeta, o que deveríamos dizer e como deveríamos escrevê-la? Dificilmente o uso dos idiomas existentes no nosso planeta ou de códigos, como o código morse, traria resultados eficazes. Segundo os cientistas, a mensagem que mais facilmente poderia ser entendida por ambas as partes seria uma mensagem esc...

  7. Neutron beam irradiation study of workload dependence of SER in a microprocessor

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, Sarah E [Los Alamos National Laboratory; Graves, Todd L [Los Alamos National Laboratory; Hong, Ted [STANFORD; Ackaret, Jerry [IBM; Sonny, Rao [IBM; Subhasish, Mitra [STANFORD; Pia, Sanda [IBM

    2009-01-01

    It is known that workloads are an important factor in soft error rates (SER), but it is proving difficult to find differentiating workloads for microprocessors. We have performed neutron beam irradiation studies of a commercial microprocessor under a wide variety of workload conditions from idle, performing no operations, to very busy workloads resembling real HPC, graphics, and business applications. There is evidence that the mean times to first indication of failure, MTFIF defined in Section II, may be different for some of the applications.

  8. ser Er:YAG en Periodoncia: Revisión bibliográfica

    OpenAIRE

    2002-01-01

    Diferentes láseres, como el CO2, Nd:YAG y ArF se han propuesto en la terapéutica periodontal. La mayor parte de ellos no han alcanzado relevancia clínica, debido a los resultados insatisfactorios obtenidos en las superficies radiculares tratadas, la generación de efectos colaterales o la ausencia de terminales de aplicación adecuados. Sin embargo, el nuevo láser Er:YAG se muestra como una prometedora alternativa en la remoción de placa bacteriana y cálculo de las superficies radiculares afect...

  9. Las dificultades sufridas por una mujer para llegar a ser biomatemática : Nancy Kopell

    OpenAIRE

    Núñez Valdés, Juan; Camas Jiménez, Inmaculada; Fernández García, Soledad

    2009-01-01

    Tras haber superado una serie de dificultades de diversos tipos, entre ellas de género, de carácter y de enfermedad, la norteamericana Nancy Kopell ha llegado a ser una de la biomatemáticas más reconocidas en la actualidad por sus excelentes contribuciones en el avance de la neurociencia, al estudiar a partir de los sistemas dinámicos las redes neuronales que gobiernan las actividades motoras rítmicas. En esta comunicación se comentan algunas de esas dificultades que ella fu...

  10. LAZER E TRABALHO: algumas reflexões a partir da ontologia do ser social

    Directory of Open Access Journals (Sweden)

    Thelma Hoehne Peres Polato

    2003-01-01

    Full Text Available Para a compreensão do lazer é preciso compreendê-lo em sua totalidade, para que se possa identificar as relações estabelecidas e as possibilidades do lazer se apresentar como potência transformadora. Na busca de possíveis caminhos que permitam a realização da emancipação humana, este estudo pretende indicar qual a contribuição que a Ontologia do Ser Social pode dar para uma melhor abordagem do tema.

  11. Electromagnetic Modelling of Raman Enhancement from Nanoscale Structures as a Means to Predict the Efficacy of SERS Substrates

    Directory of Open Access Journals (Sweden)

    Richard J. C. Brown

    2007-01-01

    Full Text Available The requirement to optimise the balance between signal enhancement and reproducibility in surface enhanced Raman spectroscopy (SERS is stimulating the development of novel substrates for enhancing Raman signals. This paper describes the application of finite element electromagnetic modelling to predict the Raman enhancement produced from a variety of SERS substrates with differently sized, spaced and shaped morphologies with nanometre dimensions. For the first time, a theoretical comparison between four major generic types of SERS substrate (including metal nanoparticles, structured surfaces, and sharp tips has been performed and the results are presented and discussed. The results of the modelling are consistent with published experimental data from similar substrates.

  12. Crisis del ser en la sociedad contemporánea. Crisis of the self in contemporary society.

    OpenAIRE

    Klimenko, Olena

    2014-01-01

    Crisis del ser en la sociedad contemporánea. Crisis of the self in contemporary society. Resumen Articulo presenta una corta reflexión sobre los aspectos espirituales y psicológicos del ser humano en la sociedad contemporánea. El siglo XX fue para el hombre una época de una progresiva caída de ideales y puntos de referencia, de amparo y apoyo, que aseguraban una relativa seguridad existencial para el ser humano. Entre estos podemos marcar tres grandes: la muerte de Dios proclamada por Nietzsc...

  13. Starting points for the reference path in the evaluation of the SER Energy Agreement for Sustainable Growth; Uitgangspunten voor het referentiepad bij de evaluatie van het SER-energieakkoord

    Energy Technology Data Exchange (ETDEWEB)

    Koelemeijer, R.; Verdonk, M. [Planbureau voor de Leefomgeving PBL, Den Haag (Netherlands); Van Dril, T.; Seebregts, A. [ECN Beleidsstudies, Amsterdam (Netherlands)

    2013-09-01

    The effect of the measures from the SER (Social and Economic Council of the Netherlands) energy agreement on energy, renewable energy and greenhouse gas emissions is assessed by ECN and PBL in relation to the so-called SER-reference path. This paper provides an overview of the assumptions for this reference path with regard to policy, macro-economic development, demography and energy prices and the CO2 price and gives the effect on the price for electricity [Dutch] Het effect van de maatregelen uit het SER-energieakkoord op energiegebruik, hernieuwbare energie en broeikasgasemissies is door ECN en PBL geraamd ten opzichte van het z.g. SER-referentiepad. Deze notitie geeft een overzicht van de gehanteerde uitgangspunten voor dit referentiepad ten aanzien van beleid, macro-economische groei, demografie en energie- en de CO2-prijs en geeft het effect daarvan op de elektriciteitsprijs.

  14. Herstellung substratgestützter, nanoporöser Aluminiumoxid-Template und ihre Anwendung für die Präparation von hocheffizienten SERS-Substraten

    OpenAIRE

    2014-01-01

    Nanostrukturen aus Gold und Silber haben sich als hochwirksame Substrate für die Oberflächenverstärkte Ramanspektroskopie (Surface Enhanced Raman Spectroscopy, SERS) erwiesen. Die hohe Verstärkung des elektromagnetischen Felds an solchen Strukturen erlaubt es, adsorbierte Moleküle in sehr geringer Konzentration bis hin zu einem Einzelmolekül mittels Ramanspektroskopie nachzuweisen und zu charakterisieren. Die praktische Umsetzung zu SERS-basierten Sensoren ist jedoch dadurch erschwert, dass e...

  15. Positive selection at codon 38 of the human KCNE1 (= minK gene and sporadic absence of 38Ser-coding mRNAs in Gly38Ser heterozygotes

    Directory of Open Access Journals (Sweden)

    Pfeufer Arne

    2009-08-01

    Full Text Available Abstract Background KCNE1 represents the regulatory beta-subunit of the slowly activating delayed rectifier potassium channel (IKs. Variants of KCNE1 have repeatedly been linked to the long-QT syndrome (LQTS, a disorder which predisposes to deafness, ventricular tachyarrhythmia, syncope, and sudden cardiac death. Results We here analyze the evolution of the common Gly38Ser variant (rs1805127, using genomic DNAs, complementary DNAs, and HEK293-expressed variants of altogether 19 mammalian species. The between species comparison reveals that the human-specific Gly38Ser polymorphism evolved under strong positive Darwinian selection, probably in adaptation to specific challenges in the fine-tuning of IKs channels. The involved amino acid exchanges (Asp > Gly, Gly > Ser are moderately radical and do not induce apparent changes in posttranslational modification. According to population genetic analyses (HapMap phase II a heterozygote advantage accounts for the maintenance of the Gly38Ser polymorphism in humans. On the other hand, the expression of the 38Ser allele seems to be disadvantageous under certain conditions, as suggested by the sporadic deficiency of 38Ser-coding mRNAs in heterozygote Central Europeans and the depletion of homozygotes 38Ser in the Yoruban sample. Conclusion We speculate that individual differences in genomic imprinting or genomic recoding might have contributed to conflicting results of recent association studies between Gly38Ser polymorphism and QT phenotype. The findings thus highlight the relevance of mRNA data in future association studies of genotypes and clinical disorders. To the best of our knowledge, they moreover provide first time evidence for a unique pattern; i.e. coincidence of positive Darwinian selection and polymorphism with a sporadically suppressed expression of one allele.

  16. O significado de ser especialista para o enfermeiro estomaterapeuta El sentido de ser especialista para el enfermero estomaterapeuta The meaning of specialization for the esterostomal therapist

    Directory of Open Access Journals (Sweden)

    Maria Angela Boccara de Paula

    2003-08-01

    Full Text Available Este estudo teve como objetivo conhecer e compreender as percepções dos estomaterapeutas em relação aos significados de ser especialista, tendo como referencial metodológico a Teoria das Representações Sociais. A análise dos discursos de 12 estomaterapeutas permitiu significar três Unidades Temáticas: o estomaterapeuta como profissional, pessoa e junto ao cliente. Representações principalmente positivas como valorização, reconhecimento, remuneração, ascensão, satisfação, vontade de crescer, destaque profissional, melhoria da qualidade da assistência e segurança do cliente foram desveladas para os enfermeiros em relação à Estomaterapia. Algumas significações negativas como cobrança e falta de reconhecimento também surgiram. Essas representações indicaram a especialização como importante dimensão no percurso profissional, fato que tem influenciado positivamente o caminhar do enfermeiro em particular do estomaterapeuta. Esse constrói sua existência no tempo, escreve sua história impulsionada para a ação autônoma e com credibilidade, que permite a conquista de espaço e a resignificação do cuidar - fundamento da arte e ciência da Enfermagem.Este estudio tuvo como objetivo conocer y comprender las percepciones de los estomaterapeutas en relación con el sentido de ser especialista, tiendo como referencial metodológico la Teoría de las Representaciones Sociales. El análisis de los discursos de 12 terapistas enterostomales (ET permitió significar tres Unidades Temáticas: el TE como profesional, persona y junto al cliente. Representaciones principalmente positivas como valoración, reconocimiento, remuneración, ascensión, satisfacción, ganas de crecer, realce profesional, mejora de la calidad de la atención y seguridad del cliente, fueron desveladas por los enfermeros en relación a la Terapia Enterostomal. Algunas significaciones negativas como cobranza y falta de reconocimiento también surgieron

  17. Portadores asintomáticos que serán sometidos a inmunosupresión

    Directory of Open Access Journals (Sweden)

    Alejandro Cañas-Coto

    2008-11-01

    Full Text Available La reactivación del virus B en portadores crónicos asintomáticos, evidenciado como aumento en la alanino aminotransferasa (ALT o aumento del ADN viral, se ha descrito en 20 a 50% de los pacientes que son sometidos a tratamiento inmunosupresor o quimioterapia por neoplasias. La mayoría de las ocasiones, las descompensaciones son asintomáticas, aunque pueden tener periodos de ictericia y descompensación severa. La reactivación ha demostrado ser mayor cuando esteroides son parte del régimen de tratamiento. Estudios no controlados han demostrado que el uso de lamivudina reduce la tasa de reactivación y las posibles complicaciones de la misma. Se recomienda que todo paciente que va a ser sometido a quimioterapia por neoplasia o tratamiento inmunosupresor sea tamizado por hepatitis B. En pacientes trasplantados, no hepático, hay estudios pequeños que demuestran que hay mayor mortalidad al reactivarse el virus. La mayoría de estos estudios se han realizado en pacientes con trasplante renal. No hay una recomendación normada sobre el manejo de estos pacientes.

  18. Control de procesos de temple con láser mediante dispositivos pirométricos

    Directory of Open Access Journals (Sweden)

    Molpeceres, C.

    2002-06-01

    Full Text Available In this work, a detailed description of an on-line control system for laser heat treatments based on pyrometric monitorization, is presented. The study includes full details concerning monitorization devices and comprehensive description of the control loop, based on a direct synthesis regulator. The system validation and exportable character of the proposed method are also discussed. Finally, results obtained for CO2 laser transformation hardening of F-114 steel are analyzed, including parametric analysis of control variables through metallurgical testing of the treated material.

    Se presenta un sistema de regulación en tiempo real del temple de aceros con láser basado en el empleo de dispositivos pirométricos de radiación. Se incluye una descripción completa del dispositivo de monitorización junto con un análisis detallado del bucle de control, basado en un regulador por síntesis directa y su validación, especificando su concepción flexible y exportable a otro tipo de sistemas y tratamientos láser diferentes al empleado en el presente trabajo. Finalmente, se analizan los resultados obtenidos aplicando el sistema en procesos reales de temple superficial en acero F-114, incluyendo un estudio paramétrico de las posibles variables de control a través de ensayos de dureza y profundidad de temple de las probetas tratadas.

  19. Performance Characteristics of Bio-Inspired Metal Nanostructures as Surface-Enhanced Raman Scattered (SERS) Substrates.

    Science.gov (United States)

    Areizaga-Martinez, Hector I; Kravchenko, Ivan; Lavrik, Nickolay V; Sepaniak, Michael J; Hernández-Rivera, Samuel P; De Jesús, Marco A

    2016-09-01

    The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leaves and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). The substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.

  20. Mutagenesis of Ser24 of cytochrome b559 α subunit affects PSⅡ activities in Chlamydomonas reinhardtii

    Institute of Scientific and Technical Information of China (English)

    MA JingJing; LI LiangBi; JING YuXiang; KUANG TingYun

    2007-01-01

    In order to study the functions of cytochrome b559 (Cyt b559) in photosystem two (PSⅡ) activity, mutant S24F of Chlamydomonas reinhardtii was constructed using site directed mutagenesis, in which Serine24 (Ser24) locating downstream of Histidine23 (His23) in c subunit of Cyt b559 was replaced by Phenylalanine (Phe). Physiological and biochemical analysis showed that mutant S24F could be grown photoautotrophically or photoheterotrophically. However, their growth rate was slower either on HSM or TAP medium than that of the control; Analysis of PSⅡ activity revealed that its oxygen evolution was about 71% of wild type (WT); The Photochemical efficiency of PSll (Fv/Fm) of S24F was reduced 0.23 compared with WT; S24F was more sensitive to strong light irradiance than the wild type; Furthermore,SDS-PAGE and Western-blotting analysis indicated that the expression levels of c subunit of Cyt b559,LHCⅡ and PsbO of S24F were a little less than those of the wild type. Overall, these data suggests that Ser24 plays a significant role in making Cyt b559 structure maintain PSⅡ complex activity of oxygen evolution although it is not directly bound to heme group.

  1. La problemática del bautismo del ser deforme (monstruo durante la Edad Moderna

    Directory of Open Access Journals (Sweden)

    Flores de la Flor, Mª Alejandra

    2014-12-01

    Full Text Available Baptism has always been one of the most important sacraments of the Holy Catholic Church. The administration was made up of a series of complex rituals in which it had to keep in mind various factors, including the soul, considered the main element allowing access to baptism, without it any being could be baptized. The birth of deformed beings (considered monsters generated, therefore, a problem that forced the clergy, in their confessors manuals, to reflect on their souls and their right to be baptized.El bautismo ha sido siempre uno de los más importantes sacramentos de la Santa Iglesia Católica. Su administración lo componían una serie de rituales complejos en los que había tener presente diferentes elementos, entre ellos el alma, considerada el elemento principal que permitía el acceso al bautismo, sin ella ningún ser podía ser bautizado. El nacimiento de los seres deformes (considerados monstruos generó, por tanto, una problemática que obligó a los clérigos, en sus manuales de confesores, a reflexionar sobre sus almas y su derecho al bautismo.

  2. Hierarchical Self-Assembly of Cu7Te5 Nanorods into Superstructures with Enhanced SERS Performance.

    Science.gov (United States)

    Zheng, Jiaojiao; Dai, Baosong; Liu, Jia; Liu, Jialong; Ji, Muwei; Liu, Jiajia; Zhou, Yuanmin; Xu, Meng; Zhang, Jiatao

    2016-12-28

    This paper reports a strategy to get self-assembly of Cu7Te5 nanorods into hierarchical superstructures: the side-by-side self-assembly of nanorods into microscale one-dimensional (1D) nanowires (primary structure), the side-by-side alignments of the 1D nanowires into two-dimensional (2D) nanowire bundles (secondary structure), and the further rolling up of the 2D bundles into three-dimensional (3D) microtubes (tertiary structure). It was found that the oleylamine (OLA)/n-dodecanethiol (DDT) mixture as a binary capping agent was key to produce Cu7Te5 nanorods in the quantum size regime with high monodispersity, and this was a prerequisite for their hierarchical self-assembly based on elaborate control of the solvent evaporation process. The obtained Cu7Te5 microtube superstructures were used as SERS substrate and showed much stronger SERS enhancement than the as-prepared Cu7Te5 nanorods before assembly. This was probably ascribed to the remarkably enhanced local electromagnetic field arising from the plasmon coupling of Cu7Te5 nanorods in the well-assembled superstructures.

  3. One step 'dip' and 'use' Ag nanostructured thin films for ultrahigh sensitive SERS Detection.

    Science.gov (United States)

    Rajkumar, Kanakaraj; Jayram, Naidu Dhanpal; Mangalaraj, Devanesan; Rajendra Kumar, Ramasamy Thangavelu

    2016-11-01

    A simple one step galvanic displacement method which involves dipping of the silicon substrate in the AgNO3/HF solution and using it for SERS application without any further process is demonstrated. The size and shape of the Ag nanoparticles changes as the deposition time is increased. Initially the shape of the particles was nearly spherical and as it grows, becomes oblong and then coalesce to form a discontinuous film with vertically grown hierarchical Ag nanostructures. The sizes of the deposited particles were in the ranges from 30nm to a discontinuous film. It also demonstrated a highly sensitive chemical detection by surface-enhanced Raman scattering of rhodamine 6G dye, down to 10(-16)M concentration. Prepared samples were able to detect lower concentrations of Melamine. Discontinuous thin films with hierarchical Ag nanostructures were obtained for 5min Ag deposition. The formation of Hot spots between the discontinuous islands and also along the hierarchical structures is responsible for the high SERS enhancement. This simple one step, fast, non-lithographic and cost effective method can be applied for various label free detection of analytes of importance.

  4. Instant synthesis of gold nanoparticles at room temperature and SERS applications

    Energy Technology Data Exchange (ETDEWEB)

    Britto Hurtado, R. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Cortez-Valadez, M., E-mail: jose.cortez@unison.mx [CONACYT-Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Ramírez-Rodríguez, L.P. [Departamento de Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Larios-Rodriguez, Eduardo [Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora (Mexico); Alvarez, Ramón A.B.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C.E.; Arizpe-Chávez, H. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Hernández-Martínez, A.R. [Centro de Física Aplicada y Tecnología Avanzada (CFATA), Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro C.P. 76130 (Mexico); Flores-Acosta, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico)

    2016-08-06

    Nowadays, gold nanoparticles (AuNps) can be used in a variety of applications, thus efficient methods to produce them are necessary. Several methods have been proposed in this area, but NPs production time is one limitation of these approaches. In this study, we propose a high competitive method to synthesize gold colloidal nanoparticles, instantaneously, using no-toxic reducing agents. These substances allow the instantaneous synthesis at room temperature, even without magnetic stirrers, ovens or ultrasonic baths. Optic analysis showed two absorption bands, associated with surface Plasmon as function of HAuCl{sub 4} concentration. The nanoparticles synthesized have a 10–20 nm size, seen by the transmission electron microscopy (TEM). Therefore, it was possible to obtain several geometric patterns of AuNps, and the synthesis was performed reducing significantly processing time. Additionally, Mie and Fuchs theories were used to predict the location of the absorption bands linked to the plasmon surface in gold nanoparticles. The Surface Enhanced Raman Spectroscopy (SERS) effect was analyzed considering natural zeolite (Chabazite) as analyte, in order to determinate its possible application in soil analysis. - Highlights: • Cubic and spherical morphologies in AuNp. • Surface plasmon prediction in cubic and spherical AuNp. • Instant synthesis of AuNp. • SERS applications in soil analysis.

  5. Detection of pathogens in food using a SERS-based assay in just a few hours

    Science.gov (United States)

    Shende, Chetan; Sengupta, Atanu; Huang, Hermes; Farquharson, Stuart

    2014-05-01

    In 2011 Escherichia, Listeria, and Salmonella species infected over 1.2 million people in the United States, resulting in over 23,000 hospitalizations and 650 deaths. In January 2013 President Obama signed into law the Food and Drug Administration (FDA) Food Safety Modernization Act (FSMA), which requires constant microbial testing of food processing equipment and food to minimize contamination and distribution of food tainted with pathogens. The challenge to preventing distribution and consumption of contaminated foods lies in the fact that just a few bacterial cells can rapidly multiply to millions, reaching infectious doses within a few days. Unfortunately, current methods used to detect these few cells rely on similar growth steps to multiply the cells to the point of detection, which also takes a few days. Consequently, there is a critical need for an analyzer that can rapidly extract and detect foodborne pathogens at 1000 colony forming units per gram of food in 1-2 hours (not days), and with a specificity that differentiates from indigenous microflora, so that false alarms are eliminated. In an effort to meet this need, we have been developing an assay that extracts such pathogens from food, selectively binds these pathogens, and produces surface-enhanced Raman spectra (SERS) when read by a Raman analyzer. Here we present SERS measurements of these pathogens in actual food samples using this assay.

  6. Regulation of dendritogenesis by ZBP1 depends on its phosphorylation at Ser181

    Directory of Open Access Journals (Sweden)

    Anna Sara Urbanska

    2014-03-01

    Full Text Available Zipcode Binding Protein 1 (ZBP1 is one of proteins involved in local translation, a mechanism present in polarized cells, enabling rapid, localized protein synthesis in response to extracellular stimuli. It was previously shown that in neurons, processes coordinated by ZBP1 are indispensable for proper axonal growth cone and spine formation. We recently showed that developing neurons with overexpressed or knockdown ZBP1 cannot obtain proper morphology. We also proved that phosphorylation of ZBP1 by Src kinase is needed for proper dendritic branching [1]. Subsequently, we asked a question about other regulators of ZBP1 during dendritogenesis. Now, we demonstrate that ZBP1 is effectively phosphorylated in vitro by mTOR kinase. We took advantage of recently published data regarding potential mTOR-dependent phosphorylation sites in ZBP1 i.e. Ser181 [2] and examined role of this phosphorylation in (i dendritic arborization and (ii cellular distribution of ZBP1. To address these questions, we constructed non-phosphorable (S181A and phosphomimicking (S181E mutants of ZBP1 fused to GFP. We observed that S181E but not S181A reversed morphological deficits caused by ZBP1 knockdown. Another observation was that distribution along the dendrites of non-phosphorable mutant was more even than distribution of wild type ZBP1, which is denser at the dendritic branching points. Thus, we concluded that Ser181 phosphorylation is involved in ZBP1 functions during dendritic growth.

  7. Bcl10 is phosphorylated on Ser138 by Ca2+/calmodulin-dependent protein kinase II.

    Science.gov (United States)

    Ishiguro, Kazuhiro; Ando, Takafumi; Goto, Hidemi; Xavier, Ramnik

    2007-03-01

    Ordered assembly of scaffold proteins Carma1-Bcl10-Malt1 determines NF-kappaB activation following T cell receptor (TCR) engagement. Carma1-Bcl10 interaction and the signaling pathway are controlled by Carma1 phosphorylation, which are induced by PKCtheta and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). In addition to Carma1 phosphorylation, previous studies have demonstrated that Bcl10 is phosphorylated in the C-terminal Ser/Thr rich region following TCR engagement. However the kinases that phosphorylate Bcl10 are incompletely understood. Here we show that CaMKII phosphorylates Bcl10 on Ser138. Furthermore, a CaMKII inhibitor, KN93, and CaMKII siRNA substantially reduce Bcl10 phosphorylation induced by phorbol myristate acetate/ionomycin. S138A mutation prolongs Bcl10-induced NF-kappaB activation, suggesting that Bcl10 phosphorylation is involved in attenuation of NF-kappaB activation. These findings suggest that CaMKII modulates NF-kappaB activation via phosphorylating Bcl10 as well as Carma1.

  8. Telmisartan Activates Endothelial Nitric Oxide Synthase via Ser1177 Phosphorylation in Vascular Endothelial Cells

    Science.gov (United States)

    Myojo, Masahiro; Nagata, Daisuke; Fujita, Daishi; Kiyosue, Arihiro; Takahashi, Masao; Satonaka, Hiroshi; Morishita, Yoshiyuki; Akimoto, Tetsu; Nagai, Ryozo; Komuro, Issei; Hirata, Yasunobu

    2014-01-01

    Because endothelial nitric oxide synthase (eNOS) has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177) in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172) and eNOS and the concentration of intracellular guanosine 3′,5′-cyclic monophosphate (cGMP). Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK) inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling. PMID:24827148

  9. Telmisartan activates endothelial nitric oxide synthase via Ser1177 phosphorylation in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Masahiro Myojo

    Full Text Available Because endothelial nitric oxide synthase (eNOS has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177 in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172 and eNOS and the concentration of intracellular guanosine 3',5'-cyclic monophosphate (cGMP. Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.

  10. Raman spectroscopy and SERS analysis of ovarian tumour derived exosomes (TEXs): a preliminary study

    Science.gov (United States)

    Kerr, Laura T.; Gubbins, Luke; Weiner Gorzel, Karolina; Sharma, Shiva; Kell, Malcolm; McCann, Amanda; Hennelly, Bryan M.

    2014-05-01

    Here we report a preliminary study based on the application of Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) to investigate the compositional differences between exosomes derived from ovarian carcinoma cells (cell line A2780) grown in normoxia (normal O2 conditions) and hypoxia (1% O2 conditions). Exosomes are integral to cell signalling, and are of interest in the study of how cells communicate within their environment. We are particularly interested in identifying whether hypoxia induced senescent cells can communi- cate via exosomes with neighbouring tumour cells, thereby causing them to become senescent and therefore radio and chemo resistant. With this goal in mind, we performed a preliminary study on the application of Raman spectroscopy and SERS to analyse the biomolecular fingerprint of both groups of exosomes and to investigate whether there exists a different biomolecular composition associated with exosomes derived from hypoxic cells in comparison to those from normoxic cells. We also applied multivariate statistical techniques for the classification of both groups of exosomes.

  11. Localized Plasmon-Stimulated Nanochemistry of Graphene Oxide on a SERS Substrate.

    Science.gov (United States)

    Ramanauskaite, Lina; Xu, Huizhong; Snitka, Valentinas

    2016-03-16

    In recent years, there has been remarkable progress in the reduction and functionalization of graphene oxide (GO) using nanoparticles and high-energy optical photons. Most of these reactions are carried out in solutions, whereas the local modification of GO on solid substrates still remains a challenge. In this work, we demonstrate the local reduction of GO and its further destruction, leading to the synthesis of polyaromatic hydrocarbons (PAHs) stimulated by localized surface plasmons (LSPs). The reduction of GO and the synthesis of PAHs have been carried out on a substrate designed for surface-enhanced Raman spectroscopy (SERS). We found that LSPs initiate the destruction of water molecules entrapped in the nanogaps between silver nanoparticles after the deposition of GO from the aqueous suspension. It was demonstrated that OH radicals, as a result of water decomposition, initiate the reduction of GO, leading to the synthesis of PAHs. The reactions have been observed in real time by using SERS. The measurement of current-voltage (I-V) characteristics through conductive atomic force microscopy (AFM), recorded in an LSP-stimulated area, have shown the increased electrical conductivity (more than ten times) compared with the conductivity of GO. The synthesis of new compounds in the LSP-stimulated area has been confirmed by the appearance of new peaks in the Raman spectra and nonlinear I-V characteristics typical for PAHs. We show that the used method allows the local modification of electrical properties of GO and controlled nanopattering of organic compounds on the surface.

  12. Metal capped polystyrene nanotubes arrays as super-hydrophobic substrates for SERS applications

    Science.gov (United States)

    Lovera, Pierre; Creedon, Niamh; Alatawi, Hanan; O'Riordan, Alan

    2014-05-01

    We present a low-cost and rapid fabrication and characterisations of polymer nanotubes based substrates inspired by a Gecko's foot, and demonstrate its suitability for Surface Enhanced Raman Scattering (SERS) applications. Substrates are fabricated in a simple, scalable and cost efficient way by melt wetting of polystyrene (PS) in an anodised alumina (AAO) template, followed by silver or gold evaporation. Scanning electron microscopy reveals the substrates are composed of a dense array of free-standing polystyrene nanotubes topped by silver nanocaps. The gaps (electromagnetic hot spots) between adjacent nanotubes are measured to be 30nm +/-15nm. SERS characterisation of the substrates, employing a monolayer of 4-aminothiophenol (4-ABT) as a model molecule, exhibits an enhancement factor of ~1.6 × 106. This value is consistent with the one obtained from 3D-Finite Difference Time Domain (3D-FDTD) simulations of a simplified version of the sample. The contact angle of the substrates is measured to be 150°, making them super-hydrophobic. This later property renders the samples compatible to very low sample volumes and highly sensitive detection (down to 408ppt) of the environmental pollutant crystal violet in water is demonstrated.

  13. Nanowire-based surface-enhanced Raman spectroscopy (SERS) for chemical warfare simulants

    Science.gov (United States)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2012-06-01

    Hand-held instruments capable of spectroscopic identification of chemical warfare agents (CWA) would find extensive use in the field. Because CWA can be toxic at very low concentrations compared to typical background levels of commonly-used compounds (flame retardants, pesticides) that are chemically similar, spectroscopic measurements have the potential to reduce false alarms by distinguishing between dangerous and benign compounds. Unfortunately, most true spectroscopic instruments (infrared spectrometers, mass spectrometers, and gas chromatograph-mass spectrometers) are bench-top instruments. Surface-acoustic wave (SAW) sensors are commercially available in hand-held form, but rely on a handful of functionalized surfaces to achieve specificity. Here, we consider the potential for a hand-held device based on surface enhanced Raman scattering (SERS) using templated nanowires as enhancing substrates. We examine the magnitude of enhancement generated by the nanowires and the specificity achieved in measurements of a range of CWA simulants. We predict the ultimate sensitivity of a device based on a nanowire-based SERS core to be 1-2 orders of magnitude greater than a comparable SAW system, with a detection limit of approximately 0.01 mg m-3.

  14. Tracking SERS-active nanoprobe intracellular uptake for chemical and biological sensing

    Science.gov (United States)

    Gregas, Molly K.; Yan, Fei; Scaffidi, Jonathan; Wang, Hsin-Neng; Khoury, Christopher; Zhang, Yan; Vo-Dinh, Tuan

    2007-09-01

    A critical aspect of the use of nanoprobes for intracellular studies in chemical and biological sensing involves a fundamental understanding of their uptake and trajectory in cells. In this study, we describe experiments using surface-enhanced Raman scattering (SERS) spectroscopy and mapping to track cellular uptake of plasmonics-active labeled nanoparticles. Three different Raman-active labels with positive, negative, and neutral charges were conjugated to silver colloidal nanoparticles with the aim of spatially and temporally profiling intracellular delivery and tracking of nanoprobes during uptake in single mammalian cells. 1-D Raman spectra and 2-D Raman mapping are used to identify and locate the probes via their SERS signal intensities. Because Raman spectroscopy is very specific for identification of chemical and molecular signatures, the development of functionalized plasmonics-active nanoprobes capable of exploring intracellular spaces and processes has the ability to provide specific information on the effects of biological and chemical pollutants in the intracellular environment. The results indicate that this technique will allow study of when, where, and how these substances affect cells and living organisms.

  15. Theoretical Study on Sers of Wagging Vibrations of Benzyl Radical Adsorbed on Silver Electrodes

    Science.gov (United States)

    Wu, De-Yin; Chen, Yan-Li; Tian, Zhong-Qun

    2016-06-01

    Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) has been used to characterize adsorbed species widely but reaction intermediates rarely on electrodes. In previous studies, the observed SERS signals were proposed from surface benzyl species due to the electrochemical reduction of benzyl chloride on silver electrode surfaces. In this work, we reinvestigated the vibrational assignments of benzyl chloride and benzyl radical as the reaction intermediate. On the basis of density functional theoretical (DFT) calculations and normal mode analysis, our systematical results provide more reasonable new assignments for both surface species. Further, we investigated adsorption configurations, binding energies, and vibrational frequency shifts of benzyl radical interacting with silver. Our calculated results show that the wagging vibration displays significant vibrational frequency shift, strong coupling with some intramolecular modes in the phenyl ring, and significant changes in intensity of Raman signals. The study also provides absolute Raman intensity in benzyl halides and discuss the enhancement effect mainly due to the binding interaction with respect to free benzyl radical.

  16. LOS SIGNIFICADOS DE SER HOMBRE ASOCIADOS AL CONSUMO DE SUSTANCIAS PSICOACTIVAS

    Directory of Open Access Journals (Sweden)

    MARCO ANTONIO TOQUERO HERNÁNDEZ

    2013-01-01

    Full Text Available e l estudio del uso de sustancias psicoactivas ( spa , desde el construc - cionismo social, implica comprender cómo se articulan los conceptos y las prácticas. e l objetivo del presente trabajo fue conocer los signifi - cados de ser hombre, en un usuario de spa . s e empleó una metodo - logía cualitativa, a través de la historia de vida, se realizó un análisis narrativo en cuatro ejes: i c onsumo de spa en la familia y entorno; ii v ida emocional; iii c ontexto de pares y i V r elación con la figura femenina. l os resultados muestran que el uso de spa en la familia y entorno es una práctica que se “naturaliza” en la vida cotidiana; en la vida emocional, es un medio para evitar el sentimiento de vulne - rabilidad como hombres; en la relación con los pares es un recurso para obtener reconocimiento; y con la figura femenina representa un medio de control. d esde una perspectiva de género, el uso de spa significa ser hombre, asumir el control y poder.

  17. Mixing thiols on the surface of silver nanoparticles: preserving antibacterial properties while introducing SERS activity

    Energy Technology Data Exchange (ETDEWEB)

    Taglietti, Angelo, E-mail: angelo.taglietti@unipv.it [Università di Pavia, Dipartimento di Chimica (Italy); Diaz Fernandez, Yuri A. [Chalmers University of Technology, Department of Chemical and Biological Engineering (Sweden); Galinetto, Pietro [Università di Pavia, Dipartimento di Fisica (Italy); Grisoli, Pietro [Università di Pavia, Dipartimento di Scienze del Farmaco (Italy); Milanese, Chiara; Pallavicini, Piersandro [Università di Pavia, Dipartimento di Chimica (Italy)

    2013-11-15

    Controlling the surface composition of self-assembled monolayers is one of the major experimental challenges in nanotechnology. Despite the significant interest of the scientific community and the considerable number of publications related to this topic, the potential in this field is still far from being fully exploited.We present in this study a versatile method to coat silver nanoparticles (AgNPs) having average diameter of 7 nm with mixed monolayers of two thiols, achieving a precise control of surface composition. Different combinations of thiols have been investigated, and the nanomaterials obtained have been characterized by complementary experimental techniques, addressing the composition of the mixed monolayer. The surface-enhanced Raman spectroscopy (SERS) effect on a Raman reporter (7-mercapto-4-methylcoumarine) introduced into the mixed monolayers has also been investigated. The antibacterial activity of the coated AgNPs was investigated, showing that the colloids were active against Escherichia coli and Staphilococcus aureus irrespective of the nature of the mixed monolayer. These materials are good candidates as SERS-tags for biological applications.

  18. Estudio del endurecimiento superficial por láser de fundiciones grises

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    Maco, A. L.

    1998-04-01

    Full Text Available Three different ferritic-pearlitic gray cast irons have been laser hardened. The influence of laser power density and scanning speed on their microstructural modification, affected depth and surface hardness have been evaluated. It was observed that when the laser energy density surpasses a certain critical value, a surface layer melts and a ledeburitic microstructure of very high hardness is obtained. Below it, a second layer of martensitic microstructure also of high hardness, is produced.

    Se ha realizado el endurecimiento superficial con láser de tres fundiciones grises de diferente composición química, cuantificándose las variaciones microestructurales introducidas, las profundidades afectadas por el tratamiento y la variación de dureza lograda al modificar tanto la densidad de potencia como la velocidad de pasada. Siempre que la densidad de energía aportada con el láser supere un cierto valor crítico, se obtiene una capa superficial que llega a fundir en el tratamiento, dando lugar a una estructura ledeburítica de muy alta dureza, obteniéndose, por debajo de ella, una segunda capa, también muy dura, de fundición martensítica.

  19. La cuestión de la moral en Ser y tiempo de Martin Heidegger

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    Lozano Díaz, Vicente

    2015-08-01

    Full Text Available In Being and Time one can perceive an attempt to establish an ethics of authenticity, as human life is described as a constant endeavour to move forward, establishing goals and striving to achieve them based on decisions and a sense of responsibility grounded in one’s understanding of oneself as an individual and a non-transferable project. But these ethics of authenticity would only be acceptable to Heidegger if considered as an ontological or metaphysical foundation independent from the truths, values or principles which, in turn, are used as criteria for specific conducts and behaviours.Se puede ver en Ser y tiempo el intento de establecer una moral de la autenticidad, pues la vida humana se considera como constante proyectarse hacia adelante, estableciendo metas e intentando cumplirlas a partir de la decisión y de la responsabilidad que surge de la propia comprensión de uno mismo como proyecto individual e intransferible. Pero esta moral de la autenticidad solo sería aceptable para Heidegger si se considerase como fundamento ontológico o metafísico independiente de las verdades, valores o principios que a su vez se utilizarían como criterios para las conductas o comportamientos concretos.

  20. O significado de ser familiar cuidador do portador de transtorno mental

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    Marília Mazzuco Sant'Ana

    2011-01-01

    Full Text Available Este es un estudio cualitativo de enfoque exploratorio, descriptivo, cuyo objetivo fue comprender el significado de ser un cuidador familiar de pacientes con trastornos mentales. El estudio se desarrolló con los familiares de los pacientes con trastornos mentales, seguido en la clinica integrada de Atención Primaria de Salud en el municipio de Biguaçu-SC, vinculada a Universidade do Vale do Itajaí. Los datos cualitativos fueron obtenidos por entrevista dialógica y analizados sobre la base de la teoría del Devenir Humano. Del análisis de los dados surgieron las siguientes categorías: la experiencia de trastorno mental en las familias; hacer frente a las dificultades y limitaciones, la interrelación con la familia y "otros"; y co-creación de las posibilidades de trascendencia. Se concluyó que viver la teoría del Devenir Humano con el familiar cuidador de pacientes con trastorno mental, implica la co-participación del enfermero en la iluminación de los significados de las situaciones vivenciadas, co-trasciendendo sus propias condiciones de ser y actuar en el mundo en busca de una mejor calidad de vida.