WorldWideScience

Sample records for bases moleculares experiencia

  1. Experiencia docente en diseño de bases de datos con la ayuda de herramientas de e-learning

    OpenAIRE

    Soler Masó, Josep; Boada Oliveras, Immaculada; Prados Carrasco, Ferran; Fabregat Gesa, Ramón; Poch Garcia, Jordi

    2009-01-01

    Una de las competencias básicas en torno a la materia de bases de datos consiste en realizar el diseño conceptual y lógico de una base de datos relacional. En este artículo se presenta la experiencia realizada en el diseño de una base de datos con un número considerable de tablas y en relación a la organización y gestión de una empresa real. Para facilitar las tareas de corrección y evaluación a los profesores implicados se ha utilizado una plataforma de e-learning que corrige diagramas entid...

  2. UNA EXPERIENCIA EN CUBA

    Directory of Open Access Journals (Sweden)

    Lucy Martin

    2003-01-01

    Full Text Available Este artículo examina, desde una perspectiva so- cial, las experiencias de trabajo que un equipo multidisciplinario del INCA lleva a cabo en tres cooperativas de producción agropecuaria (CPA del sur de La Habana y en una cooperati- va de créditos y servicios (CCS de La Palma, Pinar del Río, con el objetivo de encontrar vías complementarias del fitomejoramiento formal por la vía participativa, se pretende destacar cómo en una experiencia de fitomejoramiento con la participación de los productores, se va operando una movili- zación de cambio no solo técnico sino también social, pero que a su vez reclama, para su éxito, de un movimiento en dos direcciones: participación y descentralización. Importantes lec- turas de esta experiencia son, en primer lugar, la posibilidad de construcción de conocimiento nuevo rompiendo mitos, a tra- vés de un diálogo de saberes y con la participación de los productores al tiempo que se producen cambios no solo de alcance técnico, en el ámbito de las semillas y las variedades, sino también de carácter social. En segundo lugar, revela las posibilidades de una experiencia de esta naturaleza, como ver- tiente del desarrollo sostenible y como vía de reconstrucción desde la base de nuestro proyecto social, al posibilitar el forta- lecimiento de los productores y la articulación entre actores sociales protagónicos en el sistema de semilla y en la vida comunitaria en torno a intereses comunes.

  3. Análisis de los proyectos internacionales de ayuda al desarrollo en base a pasadas experiencias.

    OpenAIRE

    Gallardo, Juan. F.; Pajares, Silvia

    2009-01-01

    La presente comunicación se refiere a las experiencias habidas en varios Proyectos de investigación mantenidos con la Unión Europea (principalmente el Proyecto REVOLTOSO) y otras acciones de ayuda o colaboración con países iberoamericanos. Se realiza un análisis DAFO con el fin de agrupar las características, ventajas e inconvenientes de los Proyectos internacionales de ayuda al desarrollo. Se indican los productos evaluables y aquellos más evaluados en los medios académicos. Se concluye que ...

  4. Carbon Nanotube Based Molecular Electronics

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1998-01-01

    Carbon nanotubes and the nanotube heterojunctions have recently emerged as excellent candidates for nanoscale molecular electronic device components. Experimental measurements on the conductivity, rectifying behavior and conductivity-chirality correlation have also been made. While quasi-one dimensional simple heterojunctions between nanotubes with different electronic behavior can be generated by introduction of a pair of heptagon-pentagon defects in an otherwise all hexagon graphene sheet. Other complex 3- and 4-point junctions may require other mechanisms. Structural stability as well as local electronic density of states of various nanotube junctions are investigated using a generalized tight-binding molecular dynamics (GDBMD) scheme that incorporates non-orthogonality of the orbitals. The junctions investigated include straight and small angle heterojunctions of various chiralities and diameters; as well as more complex 'T' and 'Y' junctions which do not always obey the usual pentagon-heptagon pair rule. The study of local density of states (LDOS) reveal many interesting features, most prominent among them being the defect-induced states in the gap. The proposed three and four pointjunctions are one of the smallest possible tunnel junctions made entirely of carbon atoms. Furthermore the electronic behavior of the nanotube based device components can be taylored by doping with group III-V elements such as B and N, and BN nanotubes as a wide band gap semiconductor has also been realized in experiments. Structural properties of heteroatomic nanotubes comprising C, B and N will be discussed.

  5. Educación para la democracia como base de la integración en el aula. Una experiencia en Formación Profesional.

    OpenAIRE

    Fabregat Pitarch, Antonio; Gallardo Fernández, Isabel Maria

    2007-01-01

    La búsqueda de una educación democrática tiene tras de sí una amplía tradición de saberes y experiencias que nosotros respetamos y asumimos como propios pero a los que deseamos contribuir con nuevas ideas y experiencias. En el desarrollo de esta experiencia hemos tratado de conseguir el reconocimiento mutuo y estimular el acercamiento a través del trabajo colaborativo aprovechando la diferencia y disfrutando de ella. Las situaciones de aula y las actividades planteadas, han posibilitado: ...

  6. [Molecular bases of cancer immunology].

    Science.gov (United States)

    Barrera-Rodríguez, R; Peralta-Zaragoza, O; Madrid-Marina, V

    1995-01-01

    The immune system is a tight network of different types of cells and molecules. The coordinated action of these elements mounts a precise immune response against tumor cells. However, these cells present several escape mechanisms, leading to tumor progression. This paper shows several cellular and molecular events involved in the regulation of the immune response against tumor cells. The interaction of several molecules such as MHC, TcR, adhesins, tumor antigens and cytokines are discussed, as well as the most recent knowledge about escape mechanisms and immunotherapy. PMID:7502157

  7. DNA-based applications in molecular electronics

    OpenAIRE

    Linko, Veikko

    2011-01-01

    This thesis is mainly focused on DNA molecules and especially on self-assembled DNA constructs and their potential applications in nanotechnology and molecular electronics. In the field of molecular electronics the conductivity of DNA is a crucial - yet open - question, and it is of great concern, since DNA is a very promising molecule in a context of bottom-up based nanodevices due to its superior selfassembly characteristics. A key tool in all the experiments presented in ...

  8. Qt-based Molecular Graphics Application (QMGA)

    OpenAIRE

    Gabriel, A. T.; Meyer, T.; Germano, G.

    2007-01-01

    Coarse-grained modeling of molecular fluids is often based on non-spherical convex rigid bodies like ellipsoids or spherocylinders representing rodlike or platelike molecules or groups of atoms, with site-site interaction potentials depending both on the distance among the particles and the relative orientation. In this category of potentials, the Gay-Berne family has been studied most extensively. However, conventional molecular graphics programs are not designed to visualize such objects. U...

  9. Una experiencia con los kuna

    OpenAIRE

    Villalobos, Leonor Cristina de

    1996-01-01

    Me encuentro en la difícil tarea de materializar en palabras una experiencia única. De transmitir sensaciones y vivencias cargadas de magia que desestructuraron en gran medida lo que hasta ese momento formaba parte de mi vida. Es así como puedo definir mi experiencia con los indios Kuna. Tuve la oportunidad de convivir con ellos dos meses, invitada por investigadores de la Universidad de Miami, para realizar estudios sobre ectoparasitosis que afectan a esta comunidad india.

  10. Molecular magnetic materials based on porphyrin macrocyles

    OpenAIRE

    ÖNAL, Emel

    2014-01-01

    The preparation of Molecule-Based Magnets is based on the assembling carriers of magnetic moment. These may be the metal ions only with diamagnetic linkers or the metal ions connected through open-shell organic molecule. The building of novel Molecule-Based Magnets architectures following the metal-radical approach relies on the design of innovative open-shell organic molecular blocks. In this regard, we focus our strategy on the synthesis of porphyrins incorporating free radicals. Indeed, po...

  11. Environmental Phosphorus Recovery Based on Molecular Bioscavengers

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix

    technology based on biological phosphorus scavengers, to examine fundamental molecular system aspects relevant for such a technology, and to motivate the use of computational techniques throughout an iterative design process of such a technology. A wide spectrum of computational methods, from atomic...... characteristic amino acid distributions of the binding sites. Quantum mechanical methods are used to investigate how phosphate moieties are described using electronic structure methods, and molecular dynamics in combination with quantum mechanics are used to show how the dynamical interaction between phosphates......-scale quantum calculations to macro-scale fluid simulations, are employed to hint at the potential of a recovery technology based on molecular bioscavengers. As a first approach, data mining is used to obtain statistical information about how proteins in nature interact with phosphate groups, thereby revealing...

  12. Calixarene-based receptors for molecular recognition

    OpenAIRE

    YILMAZ, Mustafa; ERDEMİR, Serkan

    2013-01-01

    Calixarene-based molecular receptors have been a widely developing area in material science and technology for the last few decades. Due to their bowl-shaped geometry, calixarene macrocycles are used as hosts allowing organic and inorganic guests to coordinate/sorb onto their cavity. This work briefly reviews the recent development of calixarenes.

  13. A nanoplasmonic switch based on molecular machines

    KAUST Repository

    Zheng, Yue Bing

    2009-06-01

    We aim to develop a molecular-machine-driven nanoplasmonic switch for its use in future nanophotonic integrated circuits (ICs) that have applications in optical communication, information processing, biological and chemical sensing. Experimental data show that an Au nanodisk array, coated with rotaxane molecular machines, switches its localized surface plasmon resonances (LSPR) reversibly when it is exposed to chemical oxidants and reductants. Conversely, bare Au nanodisks and disks coated with mechanically inert control compounds, do not display the same switching behavior. Along with calculations based on time-dependent density functional theory (TDDFT), these observations suggest that the nanoscale movements within surface-bound "molecular machines" can be used as the active components in plasmonic devices. ©2009 IEEE.

  14. Nonadiabatic Molecular Dynamics Based on Trajectories

    Directory of Open Access Journals (Sweden)

    Felipe Franco de Carvalho

    2013-12-01

    Full Text Available Performing molecular dynamics in electronically excited states requires the inclusion of nonadiabatic effects to properly describe phenomena beyond the Born-Oppenheimer approximation. This article provides a survey of selected nonadiabatic methods based on quantum or classical trajectories. Among these techniques, trajectory surface hopping constitutes an interesting compromise between accuracy and efficiency for the simulation of medium- to large-scale molecular systems. This approach is, however, based on non-rigorous approximations that could compromise, in some cases, the correct description of the nonadiabatic effects under consideration and hamper a systematic improvement of the theory. With the help of an in principle exact description of nonadiabatic dynamics based on Bohmian quantum trajectories, we will investigate the origin of the main approximations in trajectory surface hopping and illustrate some of the limits of this approach by means of a few simple examples.

  15. Bases de datos bibliográficas de Historia: la experiencia del Instituto de Historia del CSIC

    OpenAIRE

    Fernández-Izquierdo, Francisco

    2000-01-01

    «..Entre los resultados del proyecto de investigación "Historia y Nuevas Tecnologías de la Información", desarrollado entre 1996 y 1999 en el Instituto de Historia del CSIC, se ha desarrollado un sistema de publicación de bases de datos bibliográficas en Internet sencillo y orientado al usuario investigador...».

  16. Towards the molecular bases of polymerase dynamics

    International Nuclear Information System (INIS)

    One aspect of the strong relationship that is known to exist between the processes of DNA replication and transcription is manifest in the coupling of the rates of movement of the replication fork (rf) and RNA polymerase (rt). We address two issues concerning the largely unexplored area of polymerase dynamics: (i) The validity of an approximate kinematic formula linking rf and rt suggested by experiments in which transcription is initiated in some prokaryotes with the antibiotic streptolydigin, and (ii) What are the molecular bases of the kinematic formula? An analysis of the available data suggests possible molecular bases for polymerase dynamics. In particular, we are led to a hypothesis: In active chromatin rt may depend on the length (λt) of the transcript of the primary messenger RNA (pre-mRNA). This new effect is subject to experimental verification. We discuss possible experiments that may be performed in order to test this prediction. (author). Refs, 6 tabs

  17. Molecular profiling of neurons based on connectivity.

    Science.gov (United States)

    Ekstrand, Mats I; Nectow, Alexander R; Knight, Zachary A; Latcha, Kaamashri N; Pomeranz, Lisa E; Friedman, Jeffrey M

    2014-05-22

    The complexity and cellular heterogeneity of neural circuitry presents a major challenge to understanding the role of discrete neural populations in controlling behavior. While neuroanatomical methods enable high-resolution mapping of neural circuitry, these approaches do not allow systematic molecular profiling of neurons based on their connectivity. Here, we report the development of an approach for molecularly profiling projective neurons. We show that ribosomes can be tagged with a camelid nanobody raised against GFP and that this system can be engineered to selectively capture translating mRNAs from neurons retrogradely labeled with GFP. Using this system, we profiled neurons projecting to the nucleus accumbens. We then used an AAV to selectively profile midbrain dopamine neurons projecting to the nucleus accumbens. By comparing the captured mRNAs from each experiment, we identified a number of markers specific to VTA dopaminergic projection neurons. The current method provides a means for profiling neurons based on their projections. PMID:24855954

  18. Decimal Integer Multiplication based on Molecular Beacons

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2013-12-01

    Full Text Available Due to the enhancement of circuit integration level, and the accelerating of working frequency of traditional computer, it requires components dimension must be constantly decreased. So encapsulation, etching and other problems of chip are becoming more and more difficult to solve, which causes its performance also become unstable. In order to overcome this problem, DNA computing as a new kind of molecular computing mode, with its high parallelism, huge amounts of storage capacity, low energy consumption advantages has received extensive attention. Being the same with traditional electronic computer, DNA computer is composed by arithmetic operations such as addition, subtraction, multiplication and dividing and basic logic units such as AND, OR, NON gate. This paper puts forward a new method to realize decimal integer multiplication based on molecular beacons. The algorithm firstly converts decimal integer to binary number, and then resolves the multiplication process into multiplication of current bit and addition of intermediate result after shifting two steps. Molecular beacon is used as multiplying unit, coding sequence is used as multiplier in this method. Based on the working principle of molecular beacon, multiplication operation of two one-bit binary is simulated. And by recording fluorescence status of molecular beacon to observe intermediate result and carry-bit situation, the final result can be obtained through addition after shifting. Examples prove that this method can realize decimal integer multiplication rapidly and accurately. This method is similar to multiplication system in traditional electronic computer, and it provides a simple, easier operation method for DNA computer to realize arithmetic operation.

  19. Progress on RNAi-based molecular medicines

    OpenAIRE

    Chen J; Xie JP

    2012-01-01

    Jing Chen, Jianping XieInstitute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, ChinaAbstract: RNA interference (RNAi) is a promising strategy to suppress the expression of disease-relevant genes and induce post-transcriptional gene silencing. Their simplicity and stability endow RNAi with great advantages in molecular medicine. Several RNA...

  20. Fullerene based devices for molecular electronics

    OpenAIRE

    G. Cuniberti; R. GUTIERREZ; Fagas, G.; Grossmann, F.; Richter, K; Schmidt, R.

    2001-01-01

    We have investigated the electronic properties of a C_60 molecule in between carbon nanotube leads. This problem has been tackled within a quantum chemical treatment utilizing a density functional theory-based LCAO approach combined with the Landauer formalism. Owing to low-dimensionality, electron transport is very sensitive to the strength and geometry of interfacial bonds. Molecular contact between interfacial atoms and electrodes gives rise to a complex conductance dependence on the elect...

  1. Experiencias en Western Australia

    Directory of Open Access Journals (Sweden)

    M.A. Pérez Fernández

    2008-01-01

    Full Text Available Décadas de uso inadecuado de los recursos naturales en Australia han llevado a la extinción de numerosas especies autóctonas. Aprendiendo de sus propios errores, se han inicido recientemente diferentes proyectos de conservación en los que participan diversos agentes interesados. La Región de los Central Ranges, en el Desierto de Gibson, pertenece al pueblo aborigen Ngaanyatjarra. En los años 90 se llevó a cabo una campaña de recolección de organismos, patrocinada por el Museo de Western Australia y el Departamento de Conservación Ambiental (DEC, en la que participaron miembros de la comunidad Ngaanyatjarra, conocedores y cuidadores del territorio. El resultado científico se tradujo en la identificación de dos nuevas especies, así como numerosas nuevas citas de plantas y animales para el territorio. La minería es una de las actividades más impactantes en Australia, pero la concienciación social ha llevado a que las compañías desarrollen importantes campañas de protección de especies. El mulgara (Dasycercus cristicaula ocupaba zonas que hoy en día se dedican a la minería, y de las que prácticamente ha desaparecido. Un programa de investigación financiado por la empresa Resolute Resources y dirigido por el Departamento de Conservación y Manejo del Territorio (CALM ha permitido identificar poblaciones de este marsupial carnívoro y diseñar un programa de manejo cuyo objetivo es evitar actuaciones incompatibles con su actividad biológica. El resultado más relevante en ambas iniciativas ha sido la colaboración entre diferentes agentes implicados, con intercambio de conocimientos y experiencias. Especialmente importante ha sido la posibilidad de diseñar planes de manejo y actuación sobre el territorio, orientados a la preservación de valores naturales y culturales antiguos.

  2. Demo 10. Experiencia de Oersted

    OpenAIRE

    Ferrer Roca, Chantal

    2013-01-01

    Objetivo: Reproducción sencilla de la experiencia de Oersted (1807) que señó el inicio de los estudios de electromagnetismo: desviación de la aguja de una brújula en presencia de un hilo conductor recorrido por corriente.

  3. As bases moleculares da hemofilia A

    Directory of Open Access Journals (Sweden)

    Simone Ferreira Pio

    2009-01-01

    Full Text Available As hemofilias são doenças hemorrágicas resultantes da deficiência de fator VIII (hemofilia A ou de fator IX (hemofilia B da coagulação, decorrentes de mutações nos genes que codificam os fatores VIII ou IX, respectivamente. A hemofilia A é mais frequente que a hemofilia B e acomete aproximadamente 1:10.000 nascimentos masculinos. A gravidade e frequência dos episódios hemorrágicos está relacionado ao nível residual de atividade de fator VIII presente no plasma e este relaciona-se ao tipo de mutação associada à doença. A clonagem do gene do fator VIII tornou possível o conhecimento das bases moleculares da hemofilia A, sendo hoje conhecidas mais de 1.000 mutações associadas à doença. O conhecimento das bases moleculares da hemofilia A permite uma melhor compreensão da relação genótipo-fenótipo da doença, tomada de condutas clínicas diferenciadas em casos de mutações associadas a um maior risco de desenvolvimento de inibidor, determinação da condição de portadora de hemofilia em mulheres relacionadas aos pacientes, implementação de programa de aconselhamento genético/orientação familiar e melhor compreensão das relações estruturais-funcionais do gene-proteína. Este artigo propõe revisar as bases moleculares da hemofilia A, os métodos laboratoriais utilizados para a caracterização das mutações e as implicações clínicas envolvidas no diagnóstico molecular da hemofilia A.Hemophilias are bleeding disorders due to deficiency of the blood coagulation factor VIII (hemophilia A or factor IX (hemophilia B, resulting from mutation on the gene coding for factor VIII or factor IX. Hemophilia A is more frequent than hemophilia B and affects 1:10,000 male newborns. The severity and frequency of hemorrhagic episodes is related to residual activity of factor VIII present in the plasma and relates to the type of mutation associated with the disorder. Cloning of the factor VIII gene has enabled researchers to

  4. Una visión panorámica de las experiencias de Telesalud en Perú

    OpenAIRE

    Ernesto Gozzer Infante

    2015-01-01

    El artículo presenta las principales experiencias de telesalud realizadas en el Perú entre los años 2002 al 2010. Analiza información de literatura publicada y documentos no publicados acerca de experiencias de telesalud públicas y privadas. A partir de esta información se consultó con 26 expertos acerca de las características de las experiencias de telesalud identificadas. Se generó una base de datos de 38 experiencias, que se describen y analizan en esta publicación. Se presenta reflexiones...

  5. Molecular diagnostics: future probe-based strategies.

    Science.gov (United States)

    Marsh, Peter; Cardy, Donald L N

    2004-01-01

    Nucleic acid amplification technologies (NAATs) represent powerful tools in clinical microbiology, particularly in areas where traditional culture-based methods alone prove insufficient. A notable advantage is in reducing the time from taking samples to reporting results. This, and the specificity and sensitivity imparted by NAATs, can help to improve patient care. Both thermal and isothermal NAATs have been adapted to aid diagnosis in clinical laboratories. Current molecular diagnostic assays are generally high-tech, and are expensive to buy and perform. Easy-to-use NAATs are beginning to appear, not only facilitating acceptable throughput in clinical laboratories, but also allowing tests to move out of the laboratory, closer to the point of care. Demand for simpler, miniaturized equipment and assays, and the trend toward personalized medicine, is leading towards the development of fully integrated automation and home-use kits. The integration of diverse disciplines, such as genomics, molecular biology, microelectromechanical systems, microfluidics, microfabrication, and organic chemistry, is behind the emerging DNA microarray technology. Development of DNA microchips allows the simultaneous detection of potentially thousands of target sequences, not only favoring high throughput, but also the potential for genotyping patient subsets with respect to their response to particular drug types (pharmakogenomics). It is envisaged that the future of probe-based technologies will see the development of fully integrated assays and devices suitable for nonskilled users. PMID:15148419

  6. Fortaleciendo experiencias en estudios cooperativos

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2011-01-01

    Como todos los años docentes del Instituto de Estudios Cooperativos de la Facultad de Ciencias Económicas intercambian en el país y en el exterior experiencias en el campo de la investigación, la docencia y la extensión vinculados al movimiento cooperativo. (Párrafo extraído del texto a modo de resumen)

  7. PET-based molecular imaging in neuroscience

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) allows non-invasive assessment of physiological, metabolic and molecular processes in humans and animals in vivo. Advances in detector technology have led to a considerable improvement in the spatial resolution of PET (1-2 mm), enabling for the first time investigations in small experimental animals such as mice. With the developments in radiochemistry and tracer technology, a variety of endogenously expressed and exogenously introduced genes can be analysed by PET. This opens up the exciting and rapidly evolving field of molecular imaging, aiming at the non-invasive localisation of a biological process of interest in normal and diseased cells in animal models and humans in vivo. The main and most intriguing advantage of molecular imaging is the kinetic analysis of a given molecular event in the same experimental subject over time. This will allow non-invasive characterisation and ''phenotyping'' of animal models of human disease at various disease stages, under certain pathophysiological stimuli and after therapeutic intervention. The potential broad applications of imaging molecular events in vivo lie in the study of cell biology, biochemistry, gene/protein function and regulation, signal transduction, transcriptional regulation and characterisation of transgenic animals. Most importantly, molecular imaging will have great implications for the identification of potential molecular therapeutic targets, in the development of new treatment strategies, and in their successful implementation into clinical application. Here, the potential impact of molecular imaging by PET in applications in neuroscience research with a special focus on neurodegeneration and neuro-oncology is reviewed. (orig.)

  8. Terapia fotodinámica (PDT en piel y estética: procedimiento, materiales y método en base a nuestra experiencia Photodinamic therapy in skin and aesthetics: procedure, matherials and method based on our experience

    Directory of Open Access Journals (Sweden)

    S. Mordon

    2012-09-01

    Full Text Available La terapia fotodinámica (PTD es un procedimiento cada vez más utilizado para tratar diversas afecciones dermatológicas y dermatoestéticas. Su aplicación obtiene buenos resultados en casos de carcinoma basocelular, enfermedad de Bowen, queratosis actínica, acné, rosácea y fotoenvejecimiento cutáneo. Los fotosensibilizantes y las fuentes de luz que se pueden utilizar son cada vez más variados, pero aún existe poco consenso en su metodología de aplicación, sistemas de irradiación y dosificaciones. En este artículo describimos los materiales y métodos disponibles en la actualidad y discutimos algunos detalles que, en base a nuestra experiencia, permiten mejorar los resultados. Presentamos también 5 casos clínicos ilustrativos de diferentes patologías.Photo Dynamic Therapy (PTD is an increasingly used technique in Dermatology and Dermocosmetics. PDT has a wide range of medical applications for the treatment of extended cutaneous cancer, offering also very good results in the treatment of basal cell carcinoma, Bowen's disease, actinic keratosis, acne, rosacea and in cutaneous rejuvenation. The sensitizers and light sources used for photoactivation are also more and more varied but there is still no consensus regarding methods and energy dosage. This study describes material and methods which are currently available and discusses a few details, that based on our own experience, can improve results. Five illustrative cases of different conditions are presented.

  9. Guatemala: Experiencias de democracia directa

    OpenAIRE

    Donis, Julio

    2008-01-01

    La utilización de mecanismos de la democracia directa ha tenido una incidencia relativa en el desarrollo de la democracia, o de manera específica en el fortalecimiento de la legitimidad del sistema político. Su efecto en la gobernabilidad también es de un peso poco sostenido y no se podría adjudicar a uno de estos ejercicios como los únicos para desarrollar estabilidad en las relaciones de poder a nivel nacional. El balance de las experiencias de orden nacional en Guatemala, basándose e...

  10. Affinity based and molecularly imprinted cryogels: Applications in biomacromolecule purification.

    Science.gov (United States)

    Andaç, Müge; Galaev, Igor Yu; Denizli, Adil

    2016-05-15

    The publications in macro-molecularly imprinted polymers have increased drastically in recent years with the development of water-based polymer systems. The macroporous structure of cryogels has allowed the use of these materials within different applications, particularly in affinity purification and molecular imprinting based methods. Due to their high selectivity, specificity, efficient mass transfer and good reproducibility, molecularly imprinted cryogels (MICs) have become attractive for researchers in the separation and purification of proteins. In this review, the recent developments in affinity based cryogels and molecularly imprinted cryogels in protein purification are reviewed comprehensively. PMID:26454622

  11. una experiencia en Mauritania

    Directory of Open Access Journals (Sweden)

    J. M. Fernández-Palacios

    2008-01-01

    Full Text Available El macizo del Tagant, en la República Islámica de Mauritania, alberga, a lo largo de una red interconectada de humedales, las últimas poblaciones de cocodrilo del desierto Crocodylus niloticus suchus, que hasta muy poco tiempo se consideraban extintas. Estas poblaciones han sido capaces de resistir la desertización del Sahara ocurrida en el Holoceno gracias a la existencia de una serie de pozas (gueltas en árabe, que se forman tras las lluvias monzónicas y que están conectadas entre sí a través de una red de cauces efímeros o permanentes que forman la Cuenca endorreica del Lago Gabou. Estos humedales, carentes de protección en la actualidad, forman además la base económica de los más de cuarenta mil habitantes del macizo, basada en la ganadería y en una precaria agricultura. Conocedor del potencial naturalístico de la zona, el Gobierno de la RIM encargó a nuestra ONG la preparación de una memoria para dar a conocer y conseguir laproteccióninternacional de la zona en el marco de la Convención Ramsar de protección de humedales (UNESCO. El presente trabajo narra como lautilización de una especie focal, el cocodrilo del desierto, para proteger estos valiosos humedales podría ser compatible con el desarrollo de una actividad turística sostenible, basado en el turismo naturalístico y científico, que posibilite un mayor desarrollo a los habitantes del Tagant.

  12. Network-Based Models in Molecular Biology

    Science.gov (United States)

    Beyer, Andreas

    Biological systems are characterized by a large number of diverse interactions. Interaction maps have been used to abstract those interactions at all biological scales ranging from food webs at the ecosystem level down to protein interaction networks at the molecular scale.

  13. Reforma educativa, experiencia e incongruencias

    OpenAIRE

    Vaca Uribe, Dr. Jorge; Universidad Veracruzana

    2012-01-01

    Ni la Secretaria de Educación Pública ni la dirigente sindical del SNTE tienen derecho a embarcar al país en una costosísima Reforma Integral de la Educación Básica (que ya está en marcha aunque poca información pública se dé) sin tomar en cuenta la experiencia acumulada por la propia SEP, por los maestros que sí trabajan y están preocupados por cumplir lo mejor posible con su labor, por los centros de investigación educativa, por las costosas (y a veces reiterativas) evaluaciones que han sid...

  14. La experiencia de Galicia Dixital.

    Directory of Open Access Journals (Sweden)

    Luis Hernández Ibañez

    2008-01-01

    Full Text Available En este artículo se describen las experiencias de los autores en el diseño y la ejecución de tres instalaciones interactivas para museos basados en el concepto de interfaces naturales, es decir, aquellos que hacen uso de los medios de comunicación utilizados por los seres humanos en su relación natural con su entorno a través de capacidades comunes tales como hablar, gesticular, caminar o tocar. Estas instalaciones son parte de la exposición permanente Galicia Dixital, en Santiago de Compostela, que se dedica a ilustrar sobre la cultura de esta región española al tiempo que introduce al visitante en las aplicaciones de las nuevas tecnologías

  15. Quantitative Molecular Thermochemistry Based on Path Integrals

    Energy Technology Data Exchange (ETDEWEB)

    Glaesemann, K R; Fried, L E

    2005-03-14

    The calculation of thermochemical data requires accurate molecular energies and heat capacities. Traditional methods rely upon the standard harmonic normal mode analysis to calculate the vibrational and rotational contributions. We utilize path integral Monte Carlo (PIMC) for going beyond the harmonic analysis, to calculate the vibrational and rotational contributions to ab initio energies. This is an application and extension of a method previously developed in our group.

  16. DESCIFRANDO LAS BASES MOLECULARES DE LA RESISTENCIA CUANTITATIVA Deciphering the Molecular Bases of Quantitative Resistance

    Directory of Open Access Journals (Sweden)

    CAMILO LÓPEZ

    2011-08-01

    Full Text Available Uno de los factores que más afectan los cultivos son las enfermedades ocasionadas por patógenos. La resistencia vegetal ha sido clásicamente dividida en dos tipos: i completa, vertical o cualitativa que es gobernada por un solo gen e ii incompleta, horizontal o cuantitativa la cual es gobernada por varios genes. Aunque la resistencia cuantitativa provee resistencia de amplio espectro y es durable, los mecanismos moleculares subyacentes no han sido estudiados en detalle. En esta revisión se propone un modelo basado en co-localización de genes similares a los genes clásicos de resistencia cualitativa con QTLs (Quantitative Trait Loci para explicar el mecanismo involucrado en el reconocimiento del patógeno durante la resistencia cuantitativa. Además se presenta información acerca del progreso obtenido en los últimos tres años para entender este tipo de resistencia, lo que culminó con la clonación de varios genes asociados a resistencia cuantitativa. En conjunto, estos datos proveen nuevas luces sobre la naturaleza genética de este tipo de resistencia y de cómo puede ser empleada en programas de mejoramiento genético.Plant pathogens are some of the most important factors affecting crop production. Classically two general types of plant resistance to pathogens have been recognized: i complete, vertical or qualitative resistance governed by a single gene; and ii incomplete, horizontal or quantitative resistance, which is governed by several genes. Although quantitative resistance provides broad spectrum and more durable resistance, the underlying molecular mechanism involved in pathogen recognition has not been deeply studied. In this review, we proposed a model to explain the molecular mechanism involved in the pathogen recognition during the quantitative resistance. This is based on the co-localization of similar classical qualitative resistance genes with QTL (Quantitative Trait Loci. In addition, information is presented about the

  17. Molecular con Base a sus Trayectorias

    Directory of Open Access Journals (Sweden)

    H. Castañeda Marín

    2007-01-01

    Full Text Available En la Dinámica Molecular (DM una configuración sucesiva es generada mediante la integración de las leyes de movimiento de Newton, las trayectorias resultantes nos dan información acerca de como las posiciones y velocidades de las partículas en el sistema cambian con el transcurso del tiempo, en este contexto lo que mayor costo computacional exige es la determinación de las fuerzas aplicadas a cada partícula en su respectiva posición. Generalmente en la DM se suelen utilizar modelos simples, donde todas las colisiones son elásticas y ocurren cuando las separaciones entre los centros de las partículas son iguales al punto de discontinuidad del potencial Al utilizar potenciales continuos la fuerza y la posición de las partículas dependen de la interacción con las restantes partículas del sistema generando una interaccion de muchos cuerpos, por lo que no es posible solucionar analíticamente tal problema lo cual implica el uso de diferencias finitas. La principal tarea en el método propuesto es particionar un número de objetos dinámicos en un pequeño numero de clústeres, de tal forma que los objetos en cada cluster sean en lo más posible similares y los objetos en diferentes clústeres son lo menos similares. El problema más importante en este contexto es la selección de una medida de similaridad pertinente, la cual será utilizada como criterio de agrupamiento. El objetivo mas amplio del trabajo consiste en el análisis de un sistema molecular donde buscamos capturar importantes eventos por ejemplo la desintegración y fusión de defectos, la técnica utilizada es el reconocimiento de patrones temporales difusos. El problema más importante que se presenta en este contexto es la opción de una medida relevante de la similaridad, que se utiliza para la definición del criterio de agrupamiento.

  18. Optimal separable bases and molecular collisions

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, L W [Univ. of California, Berkeley, CA (United States)

    1997-12-01

    A new methodology is proposed for the efficient determination of Green`s functions and eigenstates for quantum systems of two or more dimensions. For a given Hamiltonian, the best possible separable approximation is obtained from the set of all Hilbert space operators. It is shown that this determination itself, as well as the solution of the resultant approximation, are problems of reduced dimensionality for most systems of physical interest. Moreover, the approximate eigenstates constitute the optimal separable basis, in the sense of self-consistent field theory. These distorted waves give rise to a Born series with optimized convergence properties. Analytical results are presented for an application of the method to the two-dimensional shifted harmonic oscillator system. The primary interest however, is quantum reactive scattering in molecular systems. For numerical calculations, the use of distorted waves corresponds to numerical preconditioning. The new methodology therefore gives rise to an optimized preconditioning scheme for the efficient calculation of reactive and inelastic scattering amplitudes, especially at intermediate energies. This scheme is particularly suited to discrete variable representations (DVR`s) and iterative sparse matrix methods commonly employed in such calculations. State to state and cumulative reactive scattering results obtained via the optimized preconditioner are presented for the two-dimensional collinear H + H{sub 2} {yields} H{sub 2} + H system. Computational time and memory requirements for this system are drastically reduced in comparison with other methods, and results are obtained for previously prohibitive energy regimes.

  19. Optimal separable bases and molecular collisions

    International Nuclear Information System (INIS)

    A new methodology is proposed for the efficient determination of Green's functions and eigenstates for quantum systems of two or more dimensions. For a given Hamiltonian, the best possible separable approximation is obtained from the set of all Hilbert space operators. It is shown that this determination itself, as well as the solution of the resultant approximation, are problems of reduced dimensionality for most systems of physical interest. Moreover, the approximate eigenstates constitute the optimal separable basis, in the sense of self-consistent field theory. These distorted waves give rise to a Born series with optimized convergence properties. Analytical results are presented for an application of the method to the two-dimensional shifted harmonic oscillator system. The primary interest however, is quantum reactive scattering in molecular systems. For numerical calculations, the use of distorted waves corresponds to numerical preconditioning. The new methodology therefore gives rise to an optimized preconditioning scheme for the efficient calculation of reactive and inelastic scattering amplitudes, especially at intermediate energies. This scheme is particularly suited to discrete variable representations (DVR's) and iterative sparse matrix methods commonly employed in such calculations. State to state and cumulative reactive scattering results obtained via the optimized preconditioner are presented for the two-dimensional collinear H + H2 → H2 + H system. Computational time and memory requirements for this system are drastically reduced in comparison with other methods, and results are obtained for previously prohibitive energy regimes

  20. Experiencia del dolor torácico en la mujer con infarto del miocardio

    Directory of Open Access Journals (Sweden)

    EILLEN MARYIBE MILLÁN

    2009-12-01

    Full Text Available Se presentan los resultados de la investigación " La experiencia del dolor torácico en la mujer con infarto agudo del miocardio" . Es un estudio cualitativo fenomenológico, que indagó sobre la experiencia del dolor torácico de la mujer que ha sufrido un infarto agudo del miocardio. Se realizó con nueve mujeres cuyo promedio de edad era de 52 años, en su mayoría amas de casa, entrevistadas personalmente por la investigadora. Se utilizó el sistema de entrevista a profundidad, siendo la base fundamental del estudio las narraciones de las experiencias ante el fenómeno de interés. El estudio permitió identificar los elementos constitutivos de la experiencia de dolor torácico en la mujer durante el infarto, descritos bajo la perspectiva personal de cada entrevistada. Los resultados de la experiencia del dolor permiten señalar que es compleja, atemorizante, con matices dados por las situaciones y vivencias previas, y se acompaña de sentimientos de temor ante la posibilidad de morir, que comprometen los ámbitos físicos, psicológicos y emocionales de la vida de la mujer.

  1. Environmental Phosphorus Recovery Based on Molecular Bioscavengers

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix

    pressure to develop sustainable phosphorus practices as well as new technologies for phosphorus recovery. Nature has spent billions of years refining proteins that interact with phosphates. This has inspired the present work where the overall ambitions are: to facilitate the development of a recovery......Phosphorus is a ubiquitous element of all known life and as such it is found throughout numerous key molecules related to various cellular functions. The supply of phosphorus is tightly linked to global food security, since phosphorus is used to produce agricultural fertilizers, without which it...... would not be possible to feed the world population. Sadly, the current supply of phosphorus is based on the gradual depletion of limited fossil reserves, and some estimates predict that within 15-25 years we will consume more phosphorus than we can produce. There is therefore a strong international...

  2. Una visión panorámica de las experiencias de Telesalud en Perú

    Directory of Open Access Journals (Sweden)

    Ernesto Gozzer Infante

    2015-04-01

    Full Text Available El artículo presenta las principales experiencias de telesalud realizadas en el Perú entre los años 2002 al 2010. Analiza información de literatura publicada y documentos no publicados acerca de experiencias de telesalud públicas y privadas. A partir de esta información se consultó con 26 expertos acerca de las características de las experiencias de telesalud identificadas. Se generó una base de datos de 38 experiencias, que se describen y analizan en esta publicación. Se presenta reflexiones y recomendaciones para ampliar el uso de la telesalud en el Perú

  3. Una visión panorámica de las experiencias de Telesalud en Perú

    Directory of Open Access Journals (Sweden)

    Ernesto Gozzer Infante

    2015-06-01

    Full Text Available El artículo presenta las principales experiencias de telesalud realizadas en el Perú entre los años 2002 al 2010. Analiza información de literatura publicada y documentos no publicados acerca de experiencias de telesalud públicas y privadas. A partir de esta información se consultó con 26 expertos acerca de las características de las experiencias de telesalud identificadas. Se generó una base de datos de 38 experiencias, que se describen y analizan en esta publicación. Se presenta reflexiones y recomendaciones para ampliar el uso de la telesalud en el Perú

  4. Molecular partitioning based on the kinetic energy density

    Science.gov (United States)

    Noorizadeh, Siamak

    2016-05-01

    Molecular partitioning based on the kinetic energy density is performed to a number of chemical species, which show non-nuclear attractors (NNA) in their gradient maps of the electron density. It is found that NNAs are removed using this molecular partitioning and although the virial theorem is not valid for all of the basins obtained in the being used AIM, all of the atoms obtained using the new approach obey this theorem. A comparison is also made between some atomic topological parameters which are obtained from the new partitioning approach and those calculated based on the electron density partitioning.

  5. Induced base transistor fabricated by molecular beam epitaxy

    Science.gov (United States)

    Chang, C.-Y.; Liu, W. C.; Jame, M. S.; Wang, Y. H.; Luryi, S.

    1986-09-01

    A novel three-terminal hot-electron device, the induced base transistor (IBT), has been fabricated by molecular beam epitaxy. Two-dimensional electron gas induced by the applied collector field in an undoped GaAs quantum well is used as the base of the IBT. The common-base current gain alpha has been achieved as high as 0.96 under a collector bias of 2.5 V and an emitter current of 3 mA.

  6. Los saberes del arte. LA experiencia estética en Nietzsche

    Directory of Open Access Journals (Sweden)

    Luis Eduardo Gama

    2008-01-01

    sobre el arte pueda tener al interior de la esfera estética misma: ¿qué es lo específico del arte frente a otras esferas de la acción humana? ¿En qué consiste propiamente la experiencia estética? ¿Qué resulta para el individuo y para la cultura del encuentro con el fenómeno del arte? El presente artículo constituye un primer intento de responder estas cuestiones. Su base de análisis se concentra en El nacimiento de la tragedia, y en menor medida en la fisiología del arte del Crepúsculo de los ídolos. La tesis central que se defiende es que la experiencia estética para Nietzsche es esencialmente una experiencia de conocimiento, de un tipo de saber que da acceso a la verdad.

  7. Protein analysis based on molecular beacon probes and biofunctionalized nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the completion of the human genome-sequencing project, there has been a resulting change in the focus of studies from genomics to proteomics. By utilizing the inherent advantages of molecular beacon probes and biofunctionalized nanoparticles, a series of novel principles, methods and techniques have been exploited for bioanalytical and biomedical studies. This review mainly discusses the applications of molecular beacon probes and biofunctionalized nanoparticles-based technologies for realtime, in-situ, highly sensitive and highly selective protein analysis, including the nonspecific or specific protein detection and separation, protein/DNA interaction studies, cell surface protein recognition, and antigen-antibody binding process-based bacteria assays. The introduction of molecular beacon probes and biofunctionalized nanoparticles into the protein analysis area would necessarily advance the proteomics research.

  8. Physically based molecular device model in a transient circuit simulator

    International Nuclear Information System (INIS)

    Two efficient, physically based models for the real-time simulation of molecular device characteristics of single molecules are developed. These models assume that through-molecule tunnelling creates a steady-state Lorentzian distribution of excess electron density on the molecule and provides for smooth transitions for the electronic degrees of freedom between the tunnelling, molecular-excitation, and charge-hopping transport regimes. They are implemented in the fREEDATM transient circuit simulator to allow for the full integration of nanoscopic molecular devices in standard packages that simulate entire devices including CMOS circuitry. Methods are presented to estimate the parameters used in the models via either direct experimental measurement or density-functional calculations. The models require 6-8 orders of magnitude less computer time than do full a priori simulations of the properties of molecular components. Consequently, molecular components can be efficiently implemented in circuit simulators. The molecular-component models are tested by comparison with experimental results reported for 1,4-benzenedithiol

  9. Molecular Recognition: Detection of Colorless Compounds Based on Color Change

    Science.gov (United States)

    Khalafi, Lida; Kashani, Samira; Karimi, Javad

    2016-01-01

    A laboratory experiment is described in which students measure the amount of cetirizine in allergy-treatment tablets based on molecular recognition. The basis of recognition is competition of cetirizine with phenolphthalein to form an inclusion complex with ß-cyclodextrin. Phenolphthalein is pinkish under basic condition, whereas it's complex form…

  10. Fullerene-based Anchoring Groups for Molecular Electronics

    DEFF Research Database (Denmark)

    Martin, Christian A.; Ding, Dapeng; Sørensen, Jakob Kryger;

    2008-01-01

    We present results on a new fullerene-based anchoring group for molecular electronics. Using lithographic mechanically controllable break junctions in vacuum we have determined the conductance and stability of single-molecule junctions of 1,4-bis(fullero[c]pyrrolidin-1-yl)benzene. The compound can...

  11. La experiencia de paro La experiencia de paro

    Directory of Open Access Journals (Sweden)

    Enric Sanchis

    2003-01-01

    las implicaciones del paro en contextos caracterizadas por la presencia o ausencia de dispositivos de protección social. Se concluye que los consecuencias no económicas del paro actual pueden ser tan graves como lo fueron durante la Gran Depresión. Dada la relevancia que algunos economistas atribuyen a los sistemas de protección del desempleo en la explicación del nivel y duración del paro europeo, en la segunda porte se analiza la teoría de la búsqueda de empleo y sus implicaciones para la política de mercado de trabajo a la luz de la literatura sobre la experiencia de paro. Se concluye que los recortes en los dispositivos de protección tienen, en el mejor de los casos, efectos positivos muy limitados sobre el paro y que podrían verse contrarrestados por efectos de signo contrario sobre las condiciones de trabajo, localidad de vida de los parados y el grado de cohesión social. En una situación coma la española habría que dar prioridad a las políticas activas de empleo, al tratamiento personalizado de los parados y a la persecución del fraude empresarial a la Seguridad Social

  12. La experiencia del curso "bases romanistas del derecho civil" en la facultad de derecho de la Pontificia Universidad Católica del Perú

    OpenAIRE

    Marcial Rubio Correa

    1986-01-01

    Esta ponencia se inscribe dentro del tema de enseñanza del Derecho que, de acuerdo a las bases establecidas para el V Congreso Latinoamericano de Derecho Romano, es parte de sus trabajos. Es una propuesta que no pretende sustituir, sino antes bien complementar, al curso tradicional de Derecho Romano que se ha dictado desde tiempo atrás.

  13. Una experiencia carismática de base durante la dictadura militar: Comunidad “Dios con Nosotros”, 1973-1983.

    Directory of Open Access Journals (Sweden)

    Fabián Bustamante Olguín

    2009-10-01

    Full Text Available This article aims to include central, from the field of historiography, the experience of a base community catholic charismatic during the military dictatorship in the neighborhood Manuel Rodriguez now in the district of Lo Prado, between the years 1973 to 1983, plus how to search this small based community charismatic church confronted the dictatorship through a new kind of coexistence that divided the residents of Villa Manuel Rodriguez between periods.For the foregoing is considered essentially the following aspects: first, the importance the importance of the Base Ecclesial Communities (CEBs as a reconstruction of the social fabric to the repression of the early years of military dictatorship and Second, recognizing the heterogeneity of the CEBs primarily because of the totalizing that several studies have uttered these communities by emphasizing the character of political demands, ignoring in this way, their internal dynamics and realities.Based on these considerations, the hypothesis states that the "Dios con Nosotros” to rebuild the social fabric of this new population by religious practice, coupled with people of different political tendencies in a peaceful manner.

  14. La experiencia del curso "bases romanistas del derecho civil" en la facultad de derecho de la Pontificia Universidad Católica del Perú

    Directory of Open Access Journals (Sweden)

    Marcial Rubio Correa

    1986-12-01

    Full Text Available Esta ponencia se inscribe dentro del tema de enseñanza del Derecho que, de acuerdo a las bases establecidas para el V Congreso Latinoamericano de Derecho Romano, es parte de sus trabajos. Es una propuesta que no pretende sustituir, sino antes bien complementar, al curso tradicional de Derecho Romano que se ha dictado desde tiempo atrás.

  15. Intelligent DNA-based molecular diagnostics using linked genetic markers

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, D.K.; Perlin, M.W.; Hoffman, E.P.

    1994-12-31

    This paper describes a knowledge-based system for molecular diagnostics, and its application to fully automated diagnosis of X-linked genetic disorders. Molecular diagnostic information is used in clinical practice for determining genetic risks, such as carrier determination and prenatal diagnosis. Initially, blood samples are obtained from related individuals, and PCR amplification is performed. Linkage-based molecular diagnosis then entails three data analysis steps. First, for every individual, the alleles (i.e., DNA composition) are determined at specified chromosomal locations. Second, the flow of genetic material among the individuals is established. Third, the probability that a given individual is either a carrier of the disease or affected by the disease is determined. The current practice is to perform each of these three steps manually, which is costly, time consuming, labor-intensive, and error-prone. As such, the knowledge-intensive data analysis and interpretation supersede the actual experimentation effort as the major bottleneck in molecular diagnostics. By examining the human problem solving for the task, we have designed and implemented a prototype knowledge-based system capable of fully automating linkage-based molecular diagnostics in X-linked genetic disorders, including Duchenne Muscular Dystrophy (DMD). Our system uses knowledge-based interpretation of gel electrophoresis images to determine individual DNA marker labels, a constraint satisfaction search for consistent genetic flow among individuals, and a blackboard-style problem solver for risk assessment. We describe the system`s successful diagnosis of DMD carrier and affected individuals from raw clinical data.

  16. Accelerating convergence of molecular dynamics-based structural relaxation

    DEFF Research Database (Denmark)

    Christensen, Asbjørn

    2005-01-01

    We describe strategies to accelerate the terminal stage of molecular dynamics (MD)based relaxation algorithms, where a large fraction of the computational resources are used. First, we analyze the qualitative and quantitative behavior of the QuickMin family of MD relaxation algorithms and explore...... the influence of spectral properties and dimensionality of the molecular system on the algorithm efficiency. We test two algorithms, the MinMax and Lanczos, for spectral estimation from an MD trajectory, and use this to derive a practical scheme of time step adaptation in MD relaxation algorithms to...

  17. Chemical sensors based on molecularly modified metallic nanoparticles

    International Nuclear Information System (INIS)

    This paper presents a concise, although admittedly non-exhaustive, didactic review of some of the main concepts and approaches related to the use of molecularly modified metal nanoparticles in or as chemical sensors. This paper attempts to pull together different views and terminologies used in sensors based on molecularly modified metal nanoparticles, including those established upon electrochemical, optical, surface Plasmon resonance, piezoelectric and electrical transduction approaches. Finally, this paper discusses briefly the main advantages and disadvantages of each of the presented class of sensors. (review article)

  18. Aprender a innovar: una experiencia on line

    Directory of Open Access Journals (Sweden)

    Joaquín MORENO MARCHAL

    2014-11-01

    Full Text Available La creatividad y la innovación se han convertido en recursos clave en la denominada sociedad del conocimiento, que bien podría ser también llamada sociedad de la innovación. Pero innovar es una actividad compleja, que integra la aplicación de múltiples capacidades, el pensamiento divergente y convergente, la gestión de equipos humanos, la comunicación. Ahora bien, a innovar se puede, y se debe, aprender. Aprender a innovar es un reto y también una obligación para el conjunto del sistema educativo en todos sus niveles. Partiendo de estas consideraciones este trabajo expone una experiencia de aprendizaje de la creatividad y de la innovación a través de un curso totalmente on line basado en la plataforma MOODLE, en el marco del Programa de Formación Permanente de la Universidad de Cádiz. Se presenta un modelo del proceso de innovación, denominado CREALAB, de elaboración propia. Este modelo se ha utilizado como base del proceso de aprendizaje de la creatividad y de la innovación y en el diseño del curso, está organizado en torno a actividades y tiene un carácter iterativo y realimentado. Se presentan además el conjunto del diseño metodológico y los resultados obtenidos en las dos ediciones celebradas hasta el momento. El diseño del curso totalmente on line y los resultados alcanzados permiten estimar un alto potencial de aplicación, tanto a nivel personal como a nivel organizacional.

  19. Microchip-based Devices for Molecular Diagnosis of Genetic Diseases.

    Science.gov (United States)

    Cheng; Fortina; Surrey; Kricka; Wilding

    1996-09-01

    Microchips, constructed with a variety of microfabrication technologies (photolithography, micropatterning, microjet printing, light-directed chemical synthesis, laser stereochemical etching, and microcontact printing) are being applied to molecular biology. The new microchip-based analytical devices promise to solve the analytical problems faced by many molecular biologists (eg, contamination, low throughput, and high cost). They may revolutionize molecular biology and its application in clinical medicine, forensic science, and environmental monitoring. A typical biochemical analysis involves three main steps: (1) sample preparation, (2) biochemical reaction, and (3) detection (either separation or hybridization may be involved) accompanied by data acquisition and interpretation. The construction of a miniturized analyzer will therefore necessarily entail the miniaturization and integration of all three of these processes. The literature related to the miniaturization of these three processes indicates that the greatest emphasis so far is on the investigation and development of methods for the detection of nucleic acid, followed by the optimization of a biochemical reaction, such as the polymerase chain reaction. The first step involving sample preparation has received little attention. In this review the state of the art of, microchip-based, miniaturized analytical processes (eg, sample preparation, biochemical reaction, and detection of products) are outlined and the applications of microchip-based devices in the molecular diagnosis of genetic diseases are discussed. PMID:10462559

  20. Gesture Interaction Browser-Based 3D Molecular Viewer.

    Science.gov (United States)

    Virag, Ioan; Stoicu-Tivadar, Lăcrămioara; Crişan-Vida, Mihaela

    2016-01-01

    The paper presents an open source system that allows the user to interact with a 3D molecular viewer using associated hand gestures for rotating, scaling and panning the rendered model. The novelty of this approach is that the entire application is browser-based and doesn't require installation of third party plug-ins or additional software components in order to visualize the supported chemical file formats. This kind of solution is suitable for instruction of users in less IT oriented environments, like medicine or chemistry. For rendering various molecular geometries our team used GLmol (a molecular viewer written in JavaScript). The interaction with the 3D models is made with Leap Motion controller that allows real-time tracking of the user's hand gestures. The first results confirmed that the resulting application leads to a better way of understanding various types of translational bioinformatics related problems in both biomedical research and education. PMID:27350455

  1. Capacity of Diffusion-based Molecular Communication with Ligand Receptors

    CERN Document Server

    Einolghozati, Arash; Fekri, Faramarz

    2012-01-01

    A diffusion-based molecular communication system has two major components: the diffusion in the medium, and the ligand-reception. Information bits, encoded in the time variations of the concentration of molecules, are conveyed to the receiver front through the molecular diffusion in the medium. The receiver, in turn, measures the concentration of the molecules in its vicinity in order to retrieve the information. This is done via ligand-reception process. In this paper, we develop models to study the constraints imposed by the concentration sensing at the receiver side and derive the maximum rate by which a ligand-receiver can receive information. Therefore, the overall capacity of the diffusion channel with the ligand receptors can be obtained by combining the results presented in this paper with our previous work on the achievable information rate of molecular communication over the diffusion channel.

  2. Optically induced transport through semiconductor-based molecular electronics

    International Nuclear Information System (INIS)

    A tight binding model is used to investigate photoinduced tunneling current through a molecular bridge coupled to two semiconductor electrodes. A quantum master equation is developed within a non-Markovian theory based on second-order perturbation theory with respect to the molecule-semiconductor electrode coupling. The spectral functions are generated using a one dimensional alternating bond model, and the coupling between the molecule and the electrodes is expressed through a corresponding correlation function. Since the molecular bridge orbitals are inside the bandgap between the conduction and valence bands, charge carrier tunneling is inhibited in the dark. Subject to the dipole interaction with the laser field, virtual molecular states are generated via the absorption and emission of photons, and new tunneling channels open. Interesting phenomena arising from memory are noted. Such a phenomenon could serve as a switch

  3. Graph-based interpretation of the Molecular Interstellar Medium Segmentation

    CERN Document Server

    Colombo, Dario; Ginsburg, Adam; Duarte-Cabral, Ana; Hughes, Annie

    2015-01-01

    We present a generalization of the Giant Molecular Cloud (GMC) identification problem based on cluster analysis. The method we designed, SCIMES (Spectral Clustering for Interstellar Molecular Emission Segmentation) considers the dendrogram of emission in the broader framework of graph theory and utilizes spectral clustering to find discrete regions with similar emission properties. For Galactic molecular cloud structures, we show that the characteristic volume and/or integrated CO luminosity are useful criteria to define the clustering, yielding emission structures that closely reproduce "by-eye" identification results. SCIMES performs best on well-resolved, high-resolution data, making it complementary to other available algorithms. Using 12CO(1-0) data for the Orion-Monoceros complex, we demonstrate that SCIMES provides robust results against changes of the dendrogram-construction parameters, noise realizations and degraded resolution. By comparing SCIMES with other cloud decomposition approaches, we show t...

  4. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Directory of Open Access Journals (Sweden)

    Catia Algieri

    2014-07-01

    Full Text Available An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

  5. AC-ELECTROKINETICS BASED TOOLS IN NANOENGINEERING AND MOLECULAR ELECTRONICS

    Directory of Open Access Journals (Sweden)

    R. Durán

    2005-08-01

    Full Text Available Slllcon-based mlcroeledronics has been following the integration prognosls of MOORE's Law durlng the past decades and posslbly will do so for another decade or two. Physlcal, technological and also flnancialllmlts In the foreseeable future will slow down the contlnued expansiOn of this branch of mlcroeledronlcs and instead wlll force a new technological approach based on molecular-scale eledronics (MOLETRONICS. New tools are needed to allow molecular devlce manufaduring and nanoscale engineering with hlgh precision and produdivlty. One group of methods with the potentlal for use In such a manufaduring process Is based on a.c. eledrokinetlcs effeds, which are descrlbed and discussed in this paper.

  6. Algunas experiencias de innovación educativa

    Directory of Open Access Journals (Sweden)

    de Haro, J. José

    2009-09-01

    Full Text Available In this article we show some experiences in educational innovation area performed by teachers with students of ESO and Bachelor at Amor de Dios school in Barcelona (www.amordedios. org. We also discuss the characteristics of blogs, wikis and social networks, as well as their potential usage, all based on the experience carried out with the students. We also present some useful guidelines about selection of the various systems depending on teachers’ needs.Se presentan algunas de las experiencias llevadas a cabo en el ámbito de la innovación educativa con alumnos de ESO y Bachillerato en el centro concertado de educación primaria y secundaria Amor de Dios de Barcelona (www.amordedios.org. Se discuten las características de blogs, wikis y redes sociales, así como sus posibilidades de uso, todo ello en base a las experiencias realizadas con los alumnos. Igualmente se presentan algunas directrices que pueden ayudar para la selección de unos sistemas u otros según las necesidades educativas del profesor.

  7. Optimizing legacy molecular dynamics software with directive-based offload

    Science.gov (United States)

    Michael Brown, W.; Carrillo, Jan-Michael Y.; Gavhane, Nitin; Thakkar, Foram M.; Plimpton, Steven J.

    2015-10-01

    Directive-based programming models are one solution for exploiting many-core coprocessors to increase simulation rates in molecular dynamics. They offer the potential to reduce code complexity with offload models that can selectively target computations to run on the CPU, the coprocessor, or both. In this paper, we describe modifications to the LAMMPS molecular dynamics code to enable concurrent calculations on a CPU and coprocessor. We demonstrate that standard molecular dynamics algorithms can run efficiently on both the CPU and an x86-based coprocessor using the same subroutines. As a consequence, we demonstrate that code optimizations for the coprocessor also result in speedups on the CPU; in extreme cases up to 4.7X. We provide results for LAMMPS benchmarks and for production molecular dynamics simulations using the Stampede hybrid supercomputer with both Intel®  Xeon Phi™ coprocessors and NVIDIA GPUs. The optimizations presented have increased simulation rates by over 2X for organic molecules and over 7X for liquid crystals on Stampede. The optimizations are available as part of the "Intel package" supplied with LAMMPS.

  8. Graph-based interpretation of the molecular interstellar medium segmentation

    Science.gov (United States)

    Colombo, D.; Rosolowsky, E.; Ginsburg, A.; Duarte-Cabral, A.; Hughes, A.

    2015-12-01

    We present a generalization of the giant molecular cloud identification problem based on cluster analysis. The method we designed, SCIMES (Spectral Clustering for Interstellar Molecular Emission Segmentation) considers the dendrogram of emission in the broader framework of graph theory and utilizes spectral clustering to find discrete regions with similar emission properties. For Galactic molecular cloud structures, we show that the characteristic volume and/or integrated CO luminosity are useful criteria to define the clustering, yielding emission structures that closely reproduce `by-eye' identification results. SCIMES performs best on well-resolved, high-resolution data, making it complementary to other available algorithms. Using 12CO(1-0) data for the Orion-Monoceros complex, we demonstrate that SCIMES provides robust results against changes of the dendrogram-construction parameters, noise realizations and degraded resolution. By comparing SCIMES with other cloud decomposition approaches, we show that our method is able to identify all canonical clouds of the Orion-Monoceros region, avoiding the overdivision within high-resolution survey data that represents a common limitation of several decomposition algorithms. The Orion-Monoceros objects exhibit hierarchies and size-line width relationships typical to the turbulent gas in molecular clouds, although `the Scissors' region deviates from this common description. SCIMES represents a significant step forward in moving away from pixel-based cloud segmentation towards a more physical-oriented approach, where virtually all properties of the ISM can be used for the segmentation of discrete objects.

  9. [Evolution and systematics of nematodes based on molecular investigation].

    Science.gov (United States)

    Okulewicz, Anna; Perec, Agnieszka

    2004-01-01

    Evolution and systematics of nematodes based on molecular investigation. The use of molecular phylogenetics to examine the interrelationships between animal parasites, free-living nematodes, and plant parasites versus traditional classification based on morphological-ecological characters was discussed and reviewed. Distinct differences were observed between parasitic nematodes and free-living ones. Within the former group, animal parasites turned out to be distinctly different from plant parasites. Using small subunit of ribosomal RNA gene sequence from a wide range of nematodes, there is a possibility to compare animal-parasitic, plant-parasitic and free-living taxa. Nowadays the parasitic nematodes expressed sequence tag (EST) project is currently generating sequence information to provide a new source of data to examine the evolutionary history of this taxonomic group. PMID:16859012

  10. Applications of Case-Based Reasoning in Molecular Biology

    OpenAIRE

    Jurisica, Igor; Glasgow, Janice

    2004-01-01

    Case-based reasoning (CBR) is a computational reasoning paradigm that involves the storage and retrieval of past experiences to solve novel problems. It is an approach that is particularly relevant in scientific domains, where there is a wealth of data but often a lack of theories or general principles. This article describes several CBR systems that have been developed to carry out planning, analysis, and prediction in the domain of molecular biology.

  11. Polarizable Atomic Multipole-based Molecular Mechanics for Organic Molecules

    OpenAIRE

    Ren, Pengyu; Wu, Chuanjie; Ponder, Jay W.

    2011-01-01

    An empirical potential based on permanent atomic multipoles and atomic induced dipoles is reported for alkanes, alcohols, amines, sulfides, aldehydes, carboxylic acids, amides, aromatics and other small organic molecules. Permanent atomic multipole moments through quadrupole moments have been derived from gas phase ab initio molecular orbital calculations. The van der Waals parameters are obtained by fitting to gas phase homodimer QM energies and structures, as well as experimental densities ...

  12. Molecularly Imprinted Polymer Based Sensor for the Detection of Theophylline

    Science.gov (United States)

    Braga, Guilherme S.; Paterno, Leonardo G.; Fonseca, Fernando J.; del Valle, Manel

    2011-11-01

    A molecularly imprinted polymer (MIP) impedance-based sensor was employed to detect theophylline in distilled water. To evaluate its sensibility, impedance measurements were carried out in a diluted solution of theophylline (1 mM) and distilled water using MIP and NIP (reference non-imprinted polymer) sensors. MIP showed higher sensitivity to theophylline than the NIP. This feature shows their suitability for developing an electronic tongue system for determination of methylxanthines.

  13. Organization of a radioisotope based molecular biology laboratory

    International Nuclear Information System (INIS)

    Polymerase chain reaction (PCR) has revolutionized the application of molecular techniques to medicine. Together with other molecular biology techniques it is being increasingly applied to human health for identifying prognostic markers and drug resistant profiles, developing diagnostic tests and genotyping systems and for treatment follow-up of certain diseases in developed countries. Developing Member States have expressed their need to also benefit from the dissemination of molecular advances. The use of radioisotopes, as a step in the detection process or for increased sensitivity and specificity is well established, making it ideally suitable for technology transfer. Many molecular based projects using isotopes for detecting and studying micro organisms, hereditary and neoplastic diseases are received for approval every year. In keeping with the IAEA's programme, several training activities and seminars have been organized to enhance the capabilities of developing Member States to employ in vitro nuclear medicine technologies for managing their important health problems and for undertaking related basic and clinical research. The background material for this publication was collected at training activities and from feedback received from participants at research and coordination meetings. In addition, a consultants' meeting was held in June 2004 to compile the first draft of this report. Previous IAEA TECDOCS, namely IAEA-TECDOC-748 and IAEA-TECDOC-1001, focused on molecular techniques and their application to medicine while the present publication provides information on organization of the laboratory, quality assurance and radio-safety. The technology has specific requirements of the way the laboratory is organized (e.g. for avoiding contamination and false positives in PCR) and of quality assurance in order to provide accurate information to decision makers. In addition while users of the technology accept the scientific rationale of using radio

  14. Molecular Beacon CNT-based Detection of SNPs

    Science.gov (United States)

    Egorova, V. P.; Krylova, H. V.; Lipnevich, I. V.; Veligura, A. A.; Shulitsky, B. G.; Y Fedotenkova, L.

    2015-11-01

    An fluorescence quenching effect due to few-walled carbon nanotubes chemically modified by carboxyl groups has been utilized to discriminate Single Nucleotide Polymorphism (SNP). It was shown that the complex obtained from these nanotube and singlestranded primer DNA is formed due to stacking interactions between the hexagons of the nanotubes and aromatic rings of nucleotide bases as well as due to establishing of hydrogen bonds between acceptor amine groups of nucleotide bases and donor carboxyl groups of the nanotubes. It has been demonstrated that these complexes may be used to make highly effective DNA biosensors detecting SNPs which operate as molecular beacons.

  15. Three decades of structure- and property-based molecular design

    DEFF Research Database (Denmark)

    Müller, Klaus

    2014-01-01

    Roche has pioneered structure- and property-based molecular design to drug discovery. While this is an ongoing development, the past three decades feature key events that have revolutionized the way drug discovery is conducted in Big Pharma industry. It has been a great privilege to have been...... of bioinformatics. It describes the strategic shift to large compound libraries and high-throughput screening with the development of novel compound storage and ultra-high-throughput screening facilities, as well as the strategic return to focused screening of small motif-based compound libraries...

  16. Una experiencia en Matemáticas

    Directory of Open Access Journals (Sweden)

    Escribano Ródenas, M.C.

    1998-01-01

    Full Text Available Esta comunicación pretende mostrar la experiencia llevada a cabo en la asignatura “Matemáticas” en los cursos primero y cuarto de las licenciaturas en CC. Económicas y Administración y Dirección de Empresas, durante los cursos académicos 1.997/98 y cursos anteriores. El objetivo de la experiencia en primer curso es intentar realizar un repaso de lo más esencial visto por los alumnos en cursos anteriores y establecer unos mínimos de partida para la asignatura “Matemáticas”, de estas dos licenciaturas. La iniciativa fue del Departamento. En cuarto curso la experiencia se ha llevado a cabo a propuesta de los alumnos, y su objetivo ha sido realizar un repaso de la programación matemática vista en el primer curso de carrera, siendo ésta un instrumento necesario para una asignatura de cuarto curso de la licenciatura en Administración y Dirección de Empresas, denominada “Teoría y Métodos de Decisión”.

  17. Valoración por los estudiantes de la licenciatura en psicopedagogía, de una experiencia innovadora basada en estrategias de aprendizaje colaborativo y el uso del Courselab / Innovative experience evaluation in initial high school teacher based in...

    Directory of Open Access Journals (Sweden)

    Rocío SERRANO RODRÍGUEZ

    2012-03-01

    valoración positiva tanto de la experiencia como del propio desarrollo de la asignatura.       A technological society in permanent evolution requires teaching professionals with continuous training. Among the main teaching skills that teachers must currently acquire  during process of initial training, we emphasize the educational use of Information and Communication Technologies  (in Spanish its acronym is TIC and teamwork. Through this innovation experience focused on developing a workflow based on cooperative learning using CourseLab application, specific student skills are required in PC use,  navigation through Internet and ability for teamwork and problem resolution. Definitely, we pretend to complete training of future teachers in ICT environments, so they could perform teaching / learning processes  in order to match students interests and motivations, and may contribute to improvement of school success. Results of this study indicate that training teachers demand the use of similar tools to motivate themselves and adapt to teaching and learning processes. We conclude with a positive assessment of both experience and development of the subject.

  18. Affinity sensor based on immobilized molecular imprinted synthetic recognition elements.

    Science.gov (United States)

    Lenain, Pieterjan; De Saeger, Sarah; Mattiasson, Bo; Hedström, Martin

    2015-07-15

    An affinity sensor based on capacitive transduction was developed to detect a model compound, metergoline, in a continuous flow system. This system simulates the monitoring of low-molecular weight organic compounds in natural flowing waters, i.e. rivers and streams. During operation in such scenarios, control of the experimental parameters is not possible, which poses a true analytical challenge. A two-step approach was used to produce a sensor for metergoline. Submicron spherical molecularly imprinted polymers, used as recognition elements, were obtained through emulsion polymerization and subsequently coupled to the sensor surface by electropolymerization. This way, a robust and reusable sensor was obtained that regenerated spontaneously under the natural conditions in a river. Small organic compounds could be analyzed in water without manipulating the binding or regeneration conditions, thereby offering a viable tool for on-site application. PMID:25703726

  19. Classical molecular dynamics investigations of biphenyl-based carbon nanomembranes

    Directory of Open Access Journals (Sweden)

    Andreas Mrugalla

    2014-06-01

    Full Text Available Background: Free-standing carbon nanomembranes (CNM with molecular thickness and macroscopic size are fascinating objects both for fundamental reasons and for applications in nanotechnology. Although being made from simple and identical precursors their internal structure is not fully known and hard to simulate due to the large system size that is necessary to draw definite conclusions.Results: We performed large-scale classical molecular dynamics investigations of biphenyl-based carbon nanomembranes. We show that one-dimensional graphene-like stripes constitute a highly symmetric quasi one-dimensional energetically favorable ground state. This state does not cross-link. Instead cross-linked structures are formed from highly excited precursors with a sufficient amount of broken phenyls.Conclusion: The internal structure of the CNM is very likely described by a disordered metastable state which is formed in the energetic initial process of electron irradiation and depends on the process of relaxation into the sheet phase.

  20. Photomechanical Bending of Azobenzene-Based Photochromic Molecular Fibers

    Directory of Open Access Journals (Sweden)

    Riku Matsui

    2013-03-01

    Full Text Available Microfibers composed of azobenzene-based photochromic amorphous molecular materials, namely low molecular-mass photochromic materials with a glass-forming property, could be fabricated. These fibers were found to exhibit mechanical bending motion upon irradiation with a laser beam. In addition, the bending direction could be controlled by altering the polarization direction of the irradiated light without changing the position of the light source or the wavelength of the light. In-situ fluorescence observation of mass transport induced at the surface of the fiber doped with CdSe quantum dots suggested that the bending motions were related with the photoinduced mass transport taking place near the irradiated surface of the fiber.

  1. Valoración por los estudiantes de la licenciatura en psicopedagogía, de una experiencia innovadora basada en estrategias de aprendizaje colaborativo y el uso del Courselab / Innovative experience evaluation in initial high school teacher based in...

    OpenAIRE

    Serrano Rodríguez, Rocío; Muñoz González, Juan Manuel; López Cobo, Isabel

    2012-01-01

    Una sociedad en constante cambio tecnológico exige profesionales de la enseñanza en formación continua. Entre las principales competencias docentes que debe adquirir actualmente el profesorado, durante el proceso de formación inicial, podemos destacar el uso educativo de las Tecnologías de la Información y la Comunicación (TIC) y  el trabajo en equipo. A través de esta experiencia de innovación centrada en el desarrollo de una dinámica de trabajo fundamentada en el aprendizaje cooperativo...

  2. Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films.

    Science.gov (United States)

    Niroui, Farnaz; Wang, Annie I; Sletten, Ellen M; Song, Yi; Kong, Jing; Yablonovitch, Eli; Swager, Timothy M; Lang, Jeffrey H; Bulović, Vladimir

    2015-08-25

    Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a "squitch," which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on-off ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal-molecule-graphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications. PMID:26244821

  3. Polarizable Atomic Multipole-based Molecular Mechanics for Organic Molecules.

    Science.gov (United States)

    Ren, Pengyu; Wu, Chuanjie; Ponder, Jay W

    2011-10-11

    An empirical potential based on permanent atomic multipoles and atomic induced dipoles is reported for alkanes, alcohols, amines, sulfides, aldehydes, carboxylic acids, amides, aromatics and other small organic molecules. Permanent atomic multipole moments through quadrupole moments have been derived from gas phase ab initio molecular orbital calculations. The van der Waals parameters are obtained by fitting to gas phase homodimer QM energies and structures, as well as experimental densities and heats of vaporization of neat liquids. As a validation, the hydrogen bonding energies and structures of gas phase heterodimers with water are evaluated using the resulting potential. For 32 homo- and heterodimers, the association energy agrees with ab initio results to within 0.4 kcal/mol. The RMS deviation of hydrogen bond distance from QM optimized geometry is less than 0.06 Å. In addition, liquid self-diffusion and static dielectric constants computed from molecular dynamics simulation are consistent with experimental values. The force field is also used to compute the solvation free energy of 27 compounds not included in the parameterization process, with a RMS error of 0.69 kcal/mol. The results obtained in this study suggest the AMOEBA force field performs well across different environments and phases. The key algorithms involved in the electrostatic model and a protocol for developing parameters are detailed to facilitate extension to additional molecular systems. PMID:22022236

  4. Single-walled carbon nanotube based molecular switch tunnel junctions.

    Science.gov (United States)

    Diehl, Michael R; Steuerman, David W; Tseng, Hsian-Rong; Vignon, Scott A; Star, Alexander; Celestre, Paul C; Stoddart, J Fraser; Heath, James R

    2003-12-15

    This article describes two-terminal molecular switch tunnel junctions (MSTJs) which incorporate a semiconducting, single-walled carbon nanotube (SWNT) as the bottom electrode. The nanotube interacts noncovalently with a monolayer of bistable, nondegenerate [2]catenane tetracations, self-organized by their supporting amphiphilic dimyristoylphosphatidyl anions which shield the mechanically switchable tetracations from a two-micrometer wide metallic top electrode. The resulting 0.002 micron 2 area tunnel junction addresses a nanometer wide row of approximately 2000 molecules. Active and remnant current-voltage measurements demonstrated that these devices can be reconfigurably switched and repeatedly cycled between high and low current states under ambient conditions. Control compounds, including a degenerate [2]catenane, were explored in support of the mechanical origin of the switching signature. These SWNT-based MSTJs operate like previously reported silicon-based MSTJs, but differently from similar devices incorporating bottom metal electrodes. The relevance of these results with respect to the choice of electrode materials for molecular electronics devices is discussed. PMID:14714382

  5. Single-molecular diodes based on opioid derivatives.

    Science.gov (United States)

    Siqueira, M R S; Corrêa, S M; Gester, R M; Del Nero, J; Neto, A M J C

    2015-12-01

    We propose an efficient single-molecule rectifier based on a derivative of opioid. Electron transport properties are investigated within the non-equilibrium Green's function formalism combined with density functional theory. The analysis of the current-voltage characteristics indicates obvious diode-like behavior. While heroin presents rectification coefficient R>1, indicating preferential electronic current from electron-donating to electron-withdrawing, 3 and 6-acetylmorphine and morphine exhibit contrary behavior, Rresonant-tunneling diodes. In particular, the rectification rations for heroin diodes show microampere electron current with a maximum of rectification (R=9.1) at very low bias voltage of ∼0.6 V and (R=14.3)∼1.8 V with resistance varying between 0.4 and 1.5 M Ω. Once most of the current single-molecule diodes usually rectifies in nanoampere, are not stable over 1.0 V and present electrical resistance around 10 M. Molecular devices based on opioid derivatives are promising in molecular electronics. PMID:26613894

  6. La fugaz verdad de la experiencia

    OpenAIRE

    Ghiso, Alfredo

    2014-01-01

    El ensayo encuentra su sentido en la proximidad que tiene con el acontecimiento, la experiencia formativa y “con lo provisorio de la vida misma.” Surge de la reflexión de la práctica como docente universitario, en la vivencia del educador, en su actuar pedagógico reflexivo. Situado en la dinámica generativa: método/camino/ensayo/travesía/búsqueda/estrategia, se aproxima por medio de la observación y conceptualización a lo efímero, lo contingente, la novedad, la multiplicidad; fundamentado en ...

  7. TICs aplicadas en e-Government : Experiencias

    OpenAIRE

    Pesado, Patricia Mabel; De Giusti, Armando Eduardo; Pasini, Ariel C.; Estrebou, César Armando; Osella Massa, Germán Leandro; Galdámez, Nicolás; Moralejo, Lucrecia; Rodriguez, Ismael Pablo; Pousa, Adrián; Pettoruti, José Enrique; Champredonde, Raúl; Feierherd, Guillermo Eugenio; Chichizola, Franco

    2008-01-01

    Este proyecto se enfoca en la investigación y desarrollo de soluciones de Gobierno Electrónico, utilizando Tecnologías de la Información y la Comunicación. Asimismo se han iniciado procesos de for-mación de recursos humanos en el área de Civismo Digital y en Ingeniería de Softwa-re aplicada a E-Gov. Especial interés tienen las experiencias concretas (tales como el voto electrónico, la certificación de calidad en sistemas y orga-nizaciones, el estudio de sistemas distribui-dos de tiempo ...

  8. PREVI Lima y la experiencia del tiempo

    OpenAIRE

    García-Huidobro, Fernando; Torres Torriti, Diego; Tugas, Nicolás

    2010-01-01

    Compuesto por 26 proyectos, y a más de treinta años de su inicio, la experiencia del Proyecto Piloto 1 del PREVI1 en Lima, Perú, es materia de investigación por la valiosa complejidad de factores que intervienen: el collage de proyectos, la variedad tipológica, el carácter experimental de la propuesta y el tiempo que lleva sometida a diferentes intervenciones autogestionadas. EqA viajó a Lima a reconstruir el proceso de transformación de los proyectos realizados a partir de levantamientos ...

  9. Las franjas electorales en la experiencia chilena

    Directory of Open Access Journals (Sweden)

    Juan Ignacio García Rodríguez

    2013-07-01

    Full Text Available Expone la experiencia chilena sobre el establecimiento y regulación de las franjas electorales, para lo cual analiza la constitucionalidad de la franja, los principios involucrados, las disposiciones regulatorias, el papel del Consejo Nacional de Televisión, la jurisprudencia que sobre el tema ha sido emitida por el Tribunal Calificador de Elecciones y los retos que el sistema de franjas electorales enfrenta a futuro como lo es su aplicación a las elecciones primarias de los partidos políticos.

  10. TICs : Experiencias en e-Government

    OpenAIRE

    Pesado, Patricia Mabel; Pasini, Ariel C.; Chichizola, Franco; Estrebou, César Armando; Feierherd, Guillermo Eugenio; Galdámez, Nicolás; Rodriguez, Ismael Pablo; Pousa, Adrián; Pettoruti, José Enrique; Ibañez, Eduardo; Restelli, Noelia; De Giusti, Armando Eduardo

    2010-01-01

    Esta línea incluye investigación y desarrollo de soluciones de Gobierno Electrónico, utilizando Tecnologías de la Información y la Comunicación, teniendo especial interés las experiencias concretas (tales como el voto electrónico, la certificación de calidad en sistemas y organizaciones, el estudio de sistemas distribuidos de tiempo real en aplicaciones de E-Gov sobre VLDBs y la auditoría de equipamiento específico) realizadas con organismos públicos concretos (las Provincias de Río Negro y B...

  11. Graphene-based nanomaterials as molecular imaging agents.

    Science.gov (United States)

    Garg, Bhaskar; Sung, Chu-Hsun; Ling, Yong-Chien

    2015-01-01

    Molecular imaging (MI) is a noninvasive, real-time visualization of biochemical events at the cellular and molecular level within tissues, living cells, and/or intact objects that can be advantageously applied in the areas of diagnostics, therapeutics, drug discovery, and development in understanding the nanoscale reactions including enzymatic conversions and protein-protein interactions. Consequently, over the years, great advancement has been made in the development of a variety of MI agents such as peptides, aptamers, antibodies, and various nanomaterials (NMs) including single-walled carbon nanotubes. Recently, graphene, a material popularized by Geim & Novoselov, has ignited considerable research efforts to rationally design and execute a wide range of graphene-based NMs making them an attractive platform for developing highly sensitive MI agents. Owing to their exceptional physicochemical and biological properties combined with desirable surface engineering, graphene-based NMs offer stable and tunable visible emission, small hydrodynamic size, low toxicity, and high biocompatibility and thus have been explored for in vitro and in vivo imaging applications as a promising alternative of traditional imaging agents. This review begins by describing the intrinsic properties of graphene and the key MI modalities. After which, we provide an overview on the recent advances in the design and development as well as physicochemical properties of the different classes of graphene-based NMs (graphene-dye conjugates, graphene-antibody conjugates, graphene-nanoparticle composites, and graphene quantum dots) being used as MI agents for potential applications including theranostics. Finally, the major challenges and future directions in the field will be discussed. PMID:25857851

  12. Preparation and Characterization of a Polymer-Based "Molecular Accordion".

    Science.gov (United States)

    Karoyo, Abdalla H; Wilson, Lee D

    2016-03-29

    A urethane-based polymer material, denoted HDI-1, was obtained from the addition reaction of β-cyclodextrin (β-CD) with 1,6-hexamethylene diisocyanate (HDI) at the 1:1 mole ratio. In aqueous solution and ambient temperature conditions, HDI-1 adopts a compact (coiled) morphology where the cross-linker units become coiled and are partially self-included in the annular hydroxyl (interstitial) region of β-CD. As the temperature is raised or as p-nitrophenol (PNP) was included within the β-CD cavity and the noninclusion sites of the polymer, an extended (uncoiled) morphology was adopted. The equilibrium distribution between the extended and the compact forms of HDI-1 is thermally and chemically switchable, in accordance with the hydration properties and host-guest chemistry of this responsive polymer system. The molecular structure of this water-soluble urethane polymer and its host-guest complexes with PNP were investigated using spectroscopic (Raman, (1)H NMR, induced circular dichroism), dynamic light scattering (DLS), and calorimetric (DSC) methods in aqueous solution at ambient pH, and compared with native β-CD. This study reports on the unique supramolecular properties of a polymer that resembles a thermally and chemically responsive "molecular accordion". PMID:26931298

  13. Molecular based subtyping of feline mammary carcinomas and clinicopathological characterization.

    Science.gov (United States)

    Soares, Maria; Madeira, Sara; Correia, Jorge; Peleteiro, Maria; Cardoso, Fátima; Ferreira, Fernando

    2016-06-01

    Molecular classification of feline mammary carcinomas (FMC) from which specific behavioral patterns may be estimated has potential applications in veterinary clinical practice and in comparative oncology. In this perspective, the main goal of this study was to characterize both the clinical and the pathological features of the different molecular phenotypes found in a population of FMC (n = 102), using the broadly accepted IHC-based classification established by St. Gallen International Expert Consensus panel. The luminal B/HER2-negative subtype was the most common (29.4%, 30/102) followed by luminal B/HER2-positive subtype (19.6%, 20/102), triple negative basal-like (16.7%, 17/102), luminal A (14.7%, 15/102), triple negative normal-like (12.7%, 13/102) and finally, HER2-positive subtype (6.9%, 7/102). Luminal A subtype was significantly associated with smaller tumors (p = 0.024) and with well differentiated ones (p feline mammary tumors and human breast cancer, reveal that feline can be a valuable model for comparative studies. PMID:27212699

  14. A molecularly based theory for electron transfer reorganization energy

    International Nuclear Information System (INIS)

    Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory

  15. Bases moleculares de alfa-talasemia en la Argentina

    Directory of Open Access Journals (Sweden)

    Karen G Scheps

    2015-04-01

    Full Text Available La α-talasemia, es uno de los desórdenes hereditarios más frecuentes mundialmente. Al presente, el diagnóstico molecular es la única herramienta que permite el diagnóstico certero. El propósito de este trabajo fue caracterizar las bases moleculares de estos síndromes en nuestro medio, y establecer relaciones genotipo-fenotipo. Mediante la complementación de distintas técnicas de biología molecular e hibridación fluorescente in situ (FISH, se logró poner en evidencia la presencia de mutaciones α-talasémicas en 145 de 184 (78.8% pacientes estudiados con perfil hematológico compatible con α-talasemia. Dentro de este grupo, las deleciones correspondieron al defecto genético más frecuente, prevaleciendo la mutación -α3.7 en genotipos heterocigotas y homocigotas. Asimismo, en pacientes con fenotipo α0 las deleciones prevalentes fueron -MED y -CAL/CAMP. Este estudio permitió también describir una deleción de la región sub-telomérica en un paciente con α-talasemia y retraso mental. En el 7.6% de los pacientes caracterizados clínicamente como posibles α-talasémicos (microcitosis con valores de Hb A2 inferiores al 3.5%, se hallaron mutaciones β-talasémicas en estado heterocigota. Se lograron establecer perfiles hematológicos asociados a los genotipos α+ y α0 para pacientes adultos y niños. Esperamos que este trabajo pueda servir como guía para reconocer posibles portadores α-talasémicos. También permite destacar el trabajo en conjunto de médicos hematólogos, el laboratorio (bioquímico y de biología molecular y de los médicos genetistas, con el fin de proporcionar adecuado consejo genético.

  16. Molecular bases of circadian rhythmicity in renal physiology and pathology.

    Science.gov (United States)

    Bonny, Olivier; Vinciguerra, Manlio; Gumz, Michelle L; Mazzoccoli, Gianluigi

    2013-10-01

    The physiological processes that maintain body homeostasis oscillate during the day. Diurnal changes characterize kidney functions, comprising regulation of hydro-electrolytic and acid-base balance, reabsorption of small solutes and hormone production. Renal physiology is characterized by 24-h periodicity and contributes to circadian variability of blood pressure levels, related as well to nychthemeral changes of sodium sensitivity, physical activity, vascular tone, autonomic function and neurotransmitter release from sympathetic innervations. The circadian rhythmicity of body physiology is driven by central and peripheral biological clockworks and entrained by the geophysical light/dark cycle. Chronodisruption, defined as the mismatch between environmental-social cues and physiological-behavioral patterns, causes internal desynchronization of periodic functions, leading to pathophysiological mechanisms underlying degenerative, immune related, metabolic and neoplastic diseases. In this review we will address the genetic, molecular and anatomical elements that hardwire circadian rhythmicity in renal physiology and subtend disarray of time-dependent changes in renal pathology. PMID:23901050

  17. DNA Aptamer Based Nanodrugs: Molecular Engineering for Efficiency.

    Science.gov (United States)

    Cansiz, Sena; Zhang, Liqin; Wu, Cuichen; Wu, Yuan; Teng, I-Ting; Hou, Weijia; Wang, Yanyue; Wan, Shuo; Cai, Ren; Jin, Chen; Liu, Qiaoling; Tan, Weihong

    2015-10-01

    In the past two decades, the study of cancer therapy has gradually advanced to the "nano" era. Numerous novel nanomaterials armed with unique physical properties have been introduced into biomedical research. At the same time, functional nucleic acid molecules, especially aptamers, have aroused broad attention from the biomedical community. Benefiting from the advancement of molecular engineering strategies, it is now feasible to combine the cancer-specific recognition capability of aptamers with various other special functions of nanomaterials to develop cancer-specific drugs at the nanoscale. Nanodrugs are now offering an unprecedented opportunity to achieve the goal of efficient targeted delivery as well as controlled release. This review highlights some achievements made in multiple aptamer-based nanodrug systems that have emerged in recent years, including studies in the infant stage of "proof-of-concept". PMID:26177853

  18. Hydrophobic composition based on mixed-molecular weight polyethylene

    Science.gov (United States)

    Gorlenko, Nikolay; Debelova, Natalya; Sarkisov, Yuriy; Volokitin, Gennadiy; Zavyalova, Elena; Lapova, Tatyana

    2016-01-01

    The paper presents investigations of compositions based on low and high molecular weight polyethylene so as to synthesize a hydrophobic composition for moisture protection of timber. X-ray phase analysis and measurements of the tear-off force of hydrophobic coating needed to apply to the timber surface and the limiting wetting angle are carried out to detect the hydrophobic, adhesive, electrophysical, and physicochemical properties of compositions. Kinetic dependencies are given for moisture absorption of timber specimens. It is shown that the preliminary formation of the texture by the surface patterning or its treatment with low-temperature plasma with the following protective coating results in the improvement of hydrophobic properties of the suggested compositions. These compositions can be used in the capacity of water repellents to protect building materials from moisture including restoration works.

  19. Current Progress of Aptamer-Based Molecular Imaging

    OpenAIRE

    Wang, Andrew Z.; Farokhzad, Omid C.

    2014-01-01

    Aptamers, single-stranded oligonucleotides, are an important class of molecular targeting ligand. Since their discovery, aptamers have been rapidly translated into clinical practice. They have been approved as therapeutics and molecular diagnostics. Aptamers also possess several properties that make them uniquely suited to molecular imaging. This review aims to provide an overview of aptamers’ advantages as targeting ligands and their application in molecular imaging.

  20. Molecular Beacon-Based MicroRNA Imaging During Neurogenesis.

    Science.gov (United States)

    Lee, Jonghwan; Kim, Soonhag

    2016-01-01

    The fluorescence monitoring system for examining endogenous microRNA (miRNA) activity in cellular level provides crucial information on not only understanding a critical role of miRNA involving a variety of biological processes, but also evaluating miRNA expression patterns in a noninvasive manner. In this protocol, we report the details of a new procedure for a molecular beacon-based miRNA monitoring system, which includes the illustration scheme for miRNA detection strategy, exogenous miRNA detection, and measurement of endogenous miRNA expression level during neurogenesis. The fluorescence signal of miR-124a beacon quenched by BHQ2 was gradually recovered as increasing concentration of the miR-124a in tube. The functional work of miR-124a beacon was examined in intracellular environment, allowing for the internalization of the miR-124a beacon by lipofectamine, which resulted in activated fluorescent signals of the miR-124a beacon in the HeLa cells after the addition of synthetic miR-124a. The endogenous miR-124a expression level was detected by miR-124a beacon system during neurogenesis, showing brighter fluorescence intensity in cytoplasmic area of P19 cells after induction of neuronal differentiation by retinoic acid. The molecular beacon based-miRNA detection technique could be applicable to the simultaneous visualization of a variety of miRNA expression patterns using different fluorescence dyes. For the study of examining endogenous miRNA expression level using miRNA-beacon system, if cellular differentiation step is already prepared, transfection step of miR-124a beacon into P19 cells, and acquisition of activated fluorescence signal measured by confocal microscope can be conducted approximately within 6 h. PMID:26530921

  1. Dissecting plasmodesmata molecular composition by mass spectrometry-based proteomics.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Maria Françoise Bayer

    2013-01-01

    Full Text Available In plants, the intercellular communication through the membranous channels called plasmodesmata (PD; singular plasmodesma plays pivotal roles in the orchestration of development, defence responses and viral propagation. PD are dynamic structures embedded in the plant cell wall that are defined by specialised domains of the endoplasmic reticulum and the plasma membrane. PD structure and unique functions are guaranteed by their particular molecular composition. Yet, up to recent years and despite numerous approaches such as mutant screens, immunolocalisation or screening of random cDNAs, only few PD proteins had been conclusively identified and characterised. A clear breakthrough in the search of PD constituents came from mass-spectrometry-based proteomic approaches coupled with subcellular fractionation strategies. Due to their position, firmly anchored in the extracellular matrix, PD are notoriously difficult to isolate for biochemical analysis. Proteomic-based approaches have therefore first relied on the use of cell wall fractions containing embedded PD then on free PD fractions whereby PD membranes were released from the walls by enzymatic degradation. To discriminate between likely contaminants and PD protein candidates, bioinformatics tools have often been used in combination with proteomic approaches. GFP fusion proteins of selected candidates have confirmed the PD association of several protein families. Here we review the accomplishments and limitations of the proteomic based strategies to unravel the functional and structural complexity of PD. We also discuss the role of the identified PD associated proteins.

  2. Qué sujeto para qué experiencia?

    OpenAIRE

    Schwartz, Yves

    2011-01-01

    En el espacio de un dialogo aquí iniciado con la corriente de didáctica profesional este texto se propone restituir una dinámica intelectual que va del concepto de experiencia al concepto de actividad. Este último concepto parece necesitar lo que se considera como un drama en la experiencia humana (el debate de las normas) y mostrar cómo la experiencia como sedimentación inestable de actividades es una matriz permanente de la historia. ¿Cuál puede ser entonces el precepto de los saberes gener...

  3. POLYANA-A tool for the calculation of molecular radial distribution functions based on Molecular Dynamics trajectories

    Science.gov (United States)

    Dimitroulis, Christos; Raptis, Theophanes; Raptis, Vasilios

    2015-12-01

    We present an application for the calculation of radial distribution functions for molecular centres of mass, based on trajectories generated by molecular simulation methods (Molecular Dynamics, Monte Carlo). When designing this application, the emphasis was placed on ease of use as well as ease of further development. In its current version, the program can read trajectories generated by the well-known DL_POLY package, but it can be easily extended to handle other formats. It is also very easy to 'hack' the program so it can compute intermolecular radial distribution functions for groups of interaction sites rather than whole molecules.

  4. BASES MOLECULARES DA ABSORÇÃO DO FERRO

    Directory of Open Access Journals (Sweden)

    A. A. MACHADO

    2009-03-01

    Full Text Available

    O ferro é um elemento essencial a todos os organismos vivos e alterações em sua homeostase resultam em quadro de deficiência ou acúmulo, ambos com alta prevalência e relevância clínica. A última década foi marcada pela geração de conhecimentos importantes, que estão contribuindo para a elucidação dos mecanismos moleculares da homeostase do ferro. Foram identificadas proteínas, envolvidas na absorção intestinal do ferro não-heme, e progressos significativos foram feitos no entendimento da regulação da absorção intestinal do ferro, sendo identificadas várias moléculas candidatas. As bases moleculares da homeostase do ferro ainda não foram totalmente elucidadas, porém as informações já existentes sugerem que, em condições fisiológicas, a absorção, o transporte e o armazenamento sejam feitos por moléculas altamente especializadas e, em especial, a absorção, com mecanismos saturáveis em baixa concentração. No entanto, a absorção pode ocorrer por vias menos sujeitas ao controle, dependendo da sobrecarga e da natureza química do composto utilizado. Estas informações advogam a favor de uma revisão nas estratégias de combate à anemia ferropriva. PALAVRAS-CHAVE: Absorção do ferro; DMT-1; hepahestina; ceruloplasmina; ferroportina; hepcidina.

  5. Molecular biology-based diagnosis and therapy for pancreatic cancer

    International Nuclear Information System (INIS)

    Mainly described are author's investigations of the title subject through clinical and basic diagnosis/therapeutic approach. Based on their consideration of carcinogenesis and pathological features of pancreatic cancer (PC), analysis of expression of cancer-related genes in clinically available samples like pancreatic juice and cells biopsied can result in attaining their purposes. Desmoplasia, a pathological feature of PC, possibly induces resistance to therapy and one of strategies is probably its suppression. Targeting stem cells of the mesenchyma as well as those of PC is also a strategy in future. Authors' studies have revealed that quantitation of hTERT (coding teromerase) mRNA levels in PC cells micro-dissected from cytological specimens is an accurate molecular biological diagnostic method applicable clinically. Other cancer-related genes are also useful for the diagnosis and mucin (MUC) family genes are shown to be typical ones for differentiating the precancerous PC, PC and chronic pancreatisis. Efficacy of standard gemcitabine chemotherapy can be individualized with molecular markers concerned to metabolism of the drug like dCK. Radiotherapy/radio-chemotherapy are not so satisfactory for PC treatment now. Authors have found elevated MMP-2 expression and HGF/c-Met signal activation in irradiated PC cells, which can increase the invasive capability; and stimulation of phosphorylation and activation of c-Met/MARK in co-culture of irradiated PC cells with messenchymal cells from PC, which possibly leads to progression of malignancy of PC through their interaction, of which suppression, therefore, can be a new approach to increase the efficacy of radiotherapy. Authors are making effort to introducing adenovirus therapy in clinic; exempli gratia (e.g.), the virus carrying wild type p53, a cancer-suppressive gene, induces apoptosis of PC cells often having its mutated gene. (T.T.)

  6. EXPERIENCIA DE LA HISTORICIDAD E HISTORICIDAD DE LA EXPERIENCIA: EL MUNDO COMO ESPACIO HERMENÉUTICO

    Directory of Open Access Journals (Sweden)

    Mauricio Mancilla Muñoz

    2013-07-01

    Full Text Available El siguiente artículo tiene por objetivo mostrar la mutua correspondencia entre experiencia e historicidad en la obra de Hans-Georg Gadamer. La experiencia es entendida como el movimiento fundamental de la existencia histórica, la que articula las diversas esferas de la acción humana. La experiencia hermenéutica pone de manifiesto que el comprender no puede fundarse en un procedimiento metódico, sino en la forma del existir situado en el mundo. El acto hermenéutico es entendido como un continuo proceso de apropiación, que se realiza mediante el lenguaje, y donde se van actualizando nuevos significados que develan el carácter aconteciente y móvil de la interpretación. Por ello, la historicidad de la comprensión será el principio hermenéutico fundamental que excluye la posibilidad de una conciencia histórica absoluta, a favor de una “conciencia de la repercusión histórica” (wirkungsgeschtliches Bewußtseins.

  7. Base developable negative tone molecular resist based on epoxide cross-linking

    Science.gov (United States)

    Sharp, Brandon; Lawson, Richard A.; Fralick, Ashten; Narcross, Hannah; Chun, Jun Sung; Neisser, Mark; Tolbert, Laren M.; Henderson, Clifford L.

    2015-03-01

    A negative tone, aqueous base developable molecular glass resist, 3Ep, is presented that is developable in both standard organic solvents and aqueous base developers. The resist shows slightly better imaging performance in organic solvent versus aqueous base and shows a shift of E0 away from zero dose. Compared to a previously reported 4Ep resist, 3Ep appears to have a more controlled polymerization rate at equivalent conditions, which results in higher-quality patterned features. 3Ep also requires use of an underlayer to avoid de-wetting during aqueous base development.

  8. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Directory of Open Access Journals (Sweden)

    Jia-Jia Zheng

    2016-01-01

    Full Text Available Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn. Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  9. Molecularly Imprinted Polypyrrole Based Impedimentric Sensor for Theophylline Determination

    International Nuclear Information System (INIS)

    Highlights: • Sensor based on polypyrrole imprinted by theophylline (MIP) deposited on oxygen terminated boron-doped nanocrystalline diamond was developed. • This structure was applied as impedimetric sensor sensitive for theophylline. • Optimal polymer formation conditions suitable for MIP formation were elaborated. • Some analytical parameters were determined and evaluated. - Abstract: In this study development of impedimetric sensor based on oxygen terminated boron-doped nanocrystalline diamond (B:NCD:O) modified with theophylline imprinted polypyrrole is described. Hydrogen peroxide induced chemical formation of polypyrrole molecularly imprinted by theophylline was applied for the modification of conducting silicon substrate covered by B:NCD:O film. Non-imprinted polypyrrole layer was formed on similar substrate in order to prove efficiency of imprinted polypyrrole. Electrochemical impedance spectroscopy was applied for the evaluation of analyte-induced changes in electrochemical capacitance/resistance. The impact of polymerization duration on the capacitance of impedimetric sensor was estimated. A different impedance behavior was observed at different ratio of polymerized monomer and template molecule in the polymerization media. The influence of ethanol as additive to polymerization media on registered changes in capacitance/resistance was evaluated. Degradation of sensor stored in buffer solution was evaluated

  10. Pathological Bases for a Robust Application of Cancer Molecular Classification

    Directory of Open Access Journals (Sweden)

    Salvador J. Diaz-Cano

    2015-04-01

    Full Text Available Any robust classification system depends on its purpose and must refer to accepted standards, its strength relying on predictive values and a careful consideration of known factors that can affect its reliability. In this context, a molecular classification of human cancer must refer to the current gold standard (histological classification and try to improve it with key prognosticators for metastatic potential, staging and grading. Although organ-specific examples have been published based on proteomics, transcriptomics and genomics evaluations, the most popular approach uses gene expression analysis as a direct correlate of cellular differentiation, which represents the key feature of the histological classification. RNA is a labile molecule that varies significantly according with the preservation protocol, its transcription reflect the adaptation of the tumor cells to the microenvironment, it can be passed through mechanisms of intercellular transference of genetic information (exosomes, and it is exposed to epigenetic modifications. More robust classifications should be based on stable molecules, at the genetic level represented by DNA to improve reliability, and its analysis must deal with the concept of intratumoral heterogeneity, which is at the origin of tumor progression and is the byproduct of the selection process during the clonal expansion and progression of neoplasms. The simultaneous analysis of multiple DNA targets and next generation sequencing offer the best practical approach for an analytical genomic classification of tumors.

  11. Magnetic and electronic properties of porphyrin-based molecular nanowires

    International Nuclear Information System (INIS)

    Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn). Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics

  12. Magnetic and electronic properties of porphyrin-based molecular nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jia-Jia; Li, Qiao-Zhi; Dang, Jing-Shuang; Zhao, Xiang, E-mail: xzhao@mail.xjtu.edu.cn [Institute for Chemical Physics & Department of Chemistry, MOE Key Laboratory for Non-equilibrium Condensed Matter and Quantum Engineering, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Wei-Wei [Research Center for Computational Science, Institute for Molecular Science, Okazaki, Aichi 444-8585 (Japan)

    2016-01-15

    Using spin-polarized density functional theory calculations, we performed theoretical investigations on the electronic and magnetic properties of transition metal embedded porphyrin-based nanowires (TM-PNWs, TM = Cr, Mn, Co, Ni, Cu, and Zn). Our results indicate that Ni-PNW and Zn-PNW are nonmagnetic while the rest species are magnetic, and the magnetic moments in TM-PNWs and their corresponding isolated monomer structures are found to be the same. In addition, the spin coupling in the magnetic nanowires can be ignored leading to their degenerate AFM and FM states. These results can be ascribed to the weak intermetallic interactions because of the relatively large distances between neighbor TM atoms. Among all TM-PNW structures considered here, only Mn-PNW shows a half-metallic property while the others are predicted to be semiconducting. The present work paves a new way of obtaining ferromagnetic porphyrin-based nanowires with TM atoms distributed separately and orderly, which are expected to be good candidates for catalysts, energy storage and molecular spintronics.

  13. Una experiencia en la selección de pilotos aéreos

    OpenAIRE

    P. BARDERA MORA; P. GALLARDO RODRÍGUEZ; A. CHACÁRTEGUI DÍEZ; I. MARTÍNEZ LÓPEZ; J. SIEIRO ENRÍQUEZ

    2004-01-01

    El presente artículo recoge una experiencia concreta en la selección de pilotos de aeronaves, la que se lleva a cabo en el Centro de Psicología de La Flota (Base Naval de Rota). Se ha plasmado una experiencia real en la selección de personal, tal y como se lleva a cabo, en virtud de las propias necesidades. Desde que los aspirantes encuentran en la aeronáutica su vocación hasta que llegan a pilotar un avión deberán pasar muchos controles, uno de los primeros, será superar una valoración psico...

  14. RETOS Y POSIBILIDADES DE LOS CURSOS EN LÍNEA A PARTIR DE UNA EXPERIENCIA CONCRETA.

    Directory of Open Access Journals (Sweden)

    Ana Aurora Vidal Martínez

    2014-01-01

    Full Text Available ste trabajo retoma el modelo de McIsaac y Gunawardena (1996 para el diseño de interfaces de cursos en línea y revisa su eficacia en base a una experiencia. Se describe la plataforma utilizada y las competencias docentes deseables, así como el sistema tutorial brindado y la presentación/manejo de contenidos temáticos y materiales didácticos que dicha plataforma permite. Complementa este análisis los resultados de la experiencia en términos del grado de satisfacción de los participantes (estructura y diseño del curso y el registro de actividad en la plataforma, información que se obtuvo mediante una encuesta de opinión en línea y la observación no participativa.

  15. Molecular dosimetry based on radiation induced degradation of polyisobutylene

    International Nuclear Information System (INIS)

    This project investigates the possibility of qualitative measurement of radiation doses through detection of changes in the average molecular weight in the polymer Polyisobutylene (PIB). Changes in molecular weight and molecular weight distribution is detected by Gel Permeation Chromatography (GPC). The aim of the project is to decide whether or not it is possible to determine a quality difference between α-radiation (241Am, 5,5 MeV) and γ-radiation (60Co, 1,25 MeV) in the dose range 0,5 to 10 kGy by irradiation of PIB. Irradiation with 60Co changes the average number molecular weight Mn by 12% per kGy and the average weight molecular weight Mw by 23% per kGy. The presence of antioxidant in the irradiated sample inhibits a change in average molecular weight by 5% and 16% for Mn and Mw respectively. (au)

  16. LA EXPERIENCIA VIAJERA EN EDUCACIÓN

    Directory of Open Access Journals (Sweden)

    Gloria Luna Rodrigo

    1999-12-01

    Full Text Available En este trabajo se estudia el uso que se hacia de las experiencias y relatos de viajes para enseaargeografia en la escuela primaria en Gran Bretaña al final del siglo XIX y el primer tercio del XX.Los relatos más importantes eran las aventuras de exploradores y viajeros narradas por ellos mismoso transcritas de sus diarios, series de historias que adaptaban las anteriores para niños pequeños,relatos de viaje de «geógrafos naturalistas» y .movelas geográñcasw. Se consideran libros de consultapara el profesor de los que extraer ideas y vividas imágenes de los fenómenos geográficos que iluminarancon datos llenos de color y concreción los áridos y abstractos hechos de índole científica.

  17. Postiive tone resists based on network deploymerization of molecular resists

    Science.gov (United States)

    Lawson, Richard A.; Cheng, Jing; Cheshmehkani, Ameneh; Tolbert, Laren M.; Henderson, Clifford L.

    2013-03-01

    Conventional chemically amplified resists have several issues that can potentially limit their capability for sub-40 nm imaging. One of the major issues at this size scale is that the mechanical strength of positive tone CARs limits the amount of stress they can withstand during development, rinse, and drying, thus leading to problems with pattern collapse due to the high capillary forces generated during drying. This problem is exasperated by the fact that linear polymers show dramatically reduced modulus at sub-50 nm features sizes. To improve on this problem, we have made a positive tone resist based on network depolymerization of molecular resists. The resist thermally cross-links after being spin cast into thin film form through reactions between vinyl ether groups and carboxylic acid groups. By cross-linking the resist to form a dense three dimensional polymer network, the mechanical strength of the resist is greatly improved compared to linear polymers. The network is depolymerized using an acid catalyzed reaction to create development contrast that allows for patterning of the resist via development in either aqueous base or organic solvent. One drawback of the current resist design is that the free carboxylic acids on the resist molecule appear to react in solution at room temperature with both the vinyl ether groups on adjacent molecules and with any added base quencher. These reactions cause reduced effectiveness of the base quencher and produce a noticeable resist shelf life problem. Despite these limitations, the material was used to compare the effect of development in aqueous base versus organic solvent. The resist formulated in this work showed a DUV sensitivity of 7 mJ/cm2 and a contrast of 5.2 for development in either solvent or aqueous base. Under 100 keV e-beam imaging, the material showed 40 nm resolution for both development types. In standard 0.26 N TMAH, the dose-to-size was 84 μC/cm2 with 3σ LER of 14.2 nm. Using methyl isobutyl ketone

  18. Optically switchable molecular device using microsphere based junctions

    Science.gov (United States)

    Faramarzi, V.; Raimondo, C.; Reinders, F.; Mayor, M.; Samorı, P.; Doudin, B.

    2011-12-01

    Metallic planar electrodes are bridged using microspheres coated with chemisorbed azobenzene self-assembled monolayers. The circuit exhibits light-induced switching, with reproducibility over 90%, as statistically determined and compared to junctions incorporating photo-insensitive alkanethiol layers. Microsphere interconnects provide direct access to molecular transport properties, with reliability and stability, making multifunctional molecular electronics devices possible.

  19. Melamine acoustic chemosensor based on molecularly imprinted polymer film.

    Science.gov (United States)

    Pietrzyk, Agnieszka; Kutner, Wlodzimierz; Chitta, Raghu; Zandler, Melvin E; D'Souza, Francis; Sannicolò, Francesco; Mussini, Patrizia R

    2009-12-15

    A melamine piezomicrogravimetric (acoustic) chemosensor using a molecularly imprinted polymer (MIP) film has been devised and tested. The MIP films were prepared by electropolymerization of the melamine complexed by the functional monomer of the bis(bithiophene) derivative bearing an 18-crown-6 substituent 4. The structure of the MIP-melamine complex was visualized by the DFT B3LYP/3-21G(*) energy optimization calculations. The sensitivity and selectivity of the MIP film was improved by cross-linking the polymer with the bithianaphthene monomer 5 and the presence of the porogenic ionic liquid in the prepolymerization solution. After electropolymerization, the melamine template was extracted from the MIP film with an aqueous strong base solution. The measurements of UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), DPV, and EIS as well as scanning electrochemical microscopy (SECM) imaging confirmed extraction of the melamine template from the MIP film and then rebinding of the melamine analyte while the film relative roughness and porosity was determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging, respectively. The analytical as well as kinetic and thermodynamic parameters of the chemosensing were assessed under flow-injection analysis (FIA) conditions with piezoelectric microgravimetry (PM) detection. The linear concentration range for melamine detection was 5 nM to at least 1 mM with a limit of detection of approximately 5 nM. The chemosensor successfully discriminated the cyanuric acid, cyromazine, and ammeline interfering agents. PMID:19925007

  20. Molecular dynamics study of surfactant-like peptide based nanostructures.

    Science.gov (United States)

    Colherinhas, Guilherme; Fileti, Eudes

    2014-10-23

    Surfactant-like peptide (SLP) based nanostructures are investigated using all-atomistic molecular dynamics (MD) simulations. We report structure properties of nanostructures belonging to the ANK peptide group. In particular, the mathematical models for the two A3K membranes, A6K nanotube, and A9K nanorod were developed. Our MD simulation results are consistent with the experimental data, indicating that A3K membranes are stable in two different configurations: (1) SLPs are tilted relative to the normal membrane plane; (2) SLPs are interdigitated. The former configuration is energetically more stable. The cylindrical nanostructures feature a certain order of the A6K peptides. In turn, the A9K nanorod does not exhibit any long-range ordering. Both nanotube and nanorod structure contain large amounts of water inside. Consequently, these nanostructures behave similar to hydrogels. This property may be important in the context of biotechnology. Binding energy analysis-in terms of Coulomb and van der Waals contributions-unveils an increase as the peptide size increases. The electrostatic interaction constitutes 70-75% of the noncovalent attraction energy between SLPs. The nanotubular structures are notably stable, confirming that A6K peptides preferentially form nanotubes and A9K peptides preferentially form nanorods. PMID:25264942

  1. Molecular Split-Ring Resonators Based on Metal String Complexes

    CERN Document Server

    Shen, Yao; Ai, Qing; Peng, Shie-Ming; Jin, Bih-Yaw

    2014-01-01

    Metal string complexes or extended metal atom chains (EMACs) belong to a family of molecules that consist of a linear chain of directly bonded metal atoms embraced helically by four multidentate organic ligands. These four organic ligands are usually made up of repeating pyridyl units, single-nitrogen-substituted heterocyclic annulenes, bridged by independent amido groups. Here, in this paper, we show that these heterocyclic annulenes are actually nanoscale molecular split-ring resonators (SRRs) that can exhibit simultaneous negative electric permittivity and magnetic permeability in the UV-Vis region. Moreover, a monolayer of self-assembled EMACs is a periodic array of molecular SRRs which can be considered as a negative refractive index material. In the molecular scale, where the quantum-size effect is significant, we apply the tight-binding method to obtain the frequency-dependent permittivity and permeability of these molecular SRRs with their tensorial properties carefully considered.

  2. Arrays of high quality SAM-based junctions and their application in molecular diode based logic

    Science.gov (United States)

    Wan, Albert; Suchand Sangeeth, C. S.; Wang, Lejia; Yuan, Li; Jiang, Li; Nijhuis, Christian A.

    2015-11-01

    This paper describes a method to fabricate a microfluidic top-electrode that can be utilized to generate arrays of self-assembled monolayer (SAM)-based junctions. The top-electrodes consist of a liquid-metal of GaOx/EGaIn mechanically stabilized in microchannels and through-holes in polydimethylsiloxane (PDMS); these top-electrodes form molecular junctions by directly placing them onto the SAM supported by template-stripped (TS) Ag or Au bottom-electrodes. Unlike conventional techniques to form multiple junctions, our method does not require lithography to pattern the bottom-electrode and is compatible with TS bottom-electrodes, which are ultra-flat with large grains, free from potential contamination of photoresist residues, and do not have electrode-edges where the molecules are unable to pack well. We formed tunneling junctions with n-alkanethiolate SAMs in yields of ~80%, with good reproducibility and electrical stability. Temperature dependent J(V) measurements indicated that the mechanism of charge transport across the junction is coherent tunneling. To demonstrate the usefulness of these junctions, we formed molecular diodes based on SAMs with Fc head groups. These junctions rectify currents with a rectification ratio R of 45. These molecular diodes were incorporated in simple electronic circuitry to demonstrate molecular diode-based Boolean logic.This paper describes a method to fabricate a microfluidic top-electrode that can be utilized to generate arrays of self-assembled monolayer (SAM)-based junctions. The top-electrodes consist of a liquid-metal of GaOx/EGaIn mechanically stabilized in microchannels and through-holes in polydimethylsiloxane (PDMS); these top-electrodes form molecular junctions by directly placing them onto the SAM supported by template-stripped (TS) Ag or Au bottom-electrodes. Unlike conventional techniques to form multiple junctions, our method does not require lithography to pattern the bottom-electrode and is compatible with TS

  3. Optical fiber-based photomechanical molecular delivery system

    Science.gov (United States)

    Nakano, Koki; Sato, Shunichi; Kawauchi, Satoko; Ashida, Hiroshi; Nishidate, Izumi

    2014-02-01

    Molecular delivery based on nanosecond pulsed laser-induced photomechanical waves (PMWs) enables endoscopic application by using an optical fiber for laser transmission. In our previous fiber system, a laser target, which was a black natural rubber film as a laser absorbing material covered with an optically transparent polyethylene terephthalate disk to confine the laser-induced plasma, was attached to the output end of a 1 mm core diameter quartz fiber. There were two problems in that system: 1) the outer diameter was large (~2.7 mm) and 2) available peak pressure rapidly decreased with increasing pulse number. In this study, we developed a new fiber delivery system to overcome these problems. As a laser absorbing material, we used a cap-type silicone rubber containing carbon black, into which the fiber output end can simply be inserted. The fiber end surface works to confine the laser-induced plasma. The outer diameter of the fiber system was reduced to ~1.4 mm. At an output laser fluence of 1.2 J/cm2, peak pressure of the first PMW pulse exceeded ~40 MPa. With successive 10 laser pulses, decreasing rate of the peak pressure was 22%, which was considerably lower than that with the previous fiber system (82%), enabling generation of at least successive 30 pulses of PMW with the same cap-type target. With this fiber system, we attempted transfer of plasmid DNA encoding EGFP (enhanced green fluorescence protein) to the rat skin as a test tissue in vivo, showing site-selective efficient gene expression.

  4. Congenital neutropenia: diagnosis, molecular bases and patient management

    Directory of Open Access Journals (Sweden)

    Chantelot Christine

    2011-05-01

    Full Text Available Abstract The term congenital neutropenia encompasses a family of neutropenic disorders, both permanent and intermittent, severe ( When neutropenia is detected, an attempt should be made to establish the etiology, distinguishing between acquired forms (the most frequent, including post viral neutropenia and auto immune neutropenia and congenital forms that may either be isolated or part of a complex genetic disease. Except for ethnic neutropenia, which is a frequent but mild congenital form, probably with polygenic inheritance, all other forms of congenital neutropenia are extremely rare and have monogenic inheritance, which may be X-linked or autosomal, recessive or dominant. About half the forms of congenital neutropenia with no extra-hematopoetic manifestations and normal adaptive immunity are due to neutrophil elastase (ELANE mutations. Some patients have severe permanent neutropenia and frequent infections early in life, while others have mild intermittent neutropenia. Congenital neutropenia may also be associated with a wide range of organ dysfunctions, as for example in Shwachman-Diamond syndrome (associated with pancreatic insufficiency and glycogen storage disease type Ib (associated with a glycogen storage syndrome. So far, the molecular bases of 12 neutropenic disorders have been identified. Treatment of severe chronic neutropenia should focus on prevention of infections. It includes antimicrobial prophylaxis, generally with trimethoprim-sulfamethoxazole, and also granulocyte-colony-stimulating factor (G-CSF. G-CSF has considerably improved these patients' outlook. It is usually well tolerated, but potential adverse effects include thrombocytopenia, glomerulonephritis, vasculitis and osteoporosis. Long-term treatment with G-CSF, especially at high doses, augments the spontaneous risk of leukemia in patients with congenital neutropenia.

  5. experiencia psicológica del ocio

    Directory of Open Access Journals (Sweden)

    Maria Jesus Monteagudo

    2008-01-01

    Full Text Available El presente artículo aborda desde una perspectiva actual el tema de los Beneficios del Ocio, uno de los conceptos esenciales en el estudio del ocio como factor de desarrollo personal y social. Se aporta una visión evolutiva del concepto a través de diferentes corrientes teóricas, subrayando la importancia de los beneficios del ocio entendidos desde una acepción: como mejora de una condición o situación de una persona, grupo o entidad, como prevención y/o mantenimiento y finalmente, como consecución de una experiencia psicológica satisfactoria en el marco de un ocio ajustado. Desde la perspectiva de la autora, el ocio promueve la consecución de dos tipos de beneficios, intermedios y finales, que contribuyen a mejorar el bienestar y la calidad de vida de los ciudadanos. Los profesionales del ocio procedentes tanto del sector público como del privado deberían tomar conciencia de los beneficios que pueden promoverse a través del ocio e incorporar estos conocimientos en el diseño de políticas, estrategias de gestión y modelos de intervención en ocio

  6. Experiencias de adolescentes embarazadas en control prenatal

    Directory of Open Access Journals (Sweden)

    Hilda Evelia Prías-Vanegas

    2009-01-01

    Full Text Available Objetivo: describir e interpretar las experiencias relacionadas con los sentimientos e ideas experimentados por las adolescentes al conocer su estado de embarazo. Método: se trabajó con un grupo de 22 adolescentes de instituciones públicas de I nivel de salud de Sincelejo, Colombia. El estudio, realizado en 2005, se abordó desde un enfoque cualitativo, con información recogida en entrevistas personales, grabadas con consentimiento de las jóvenes. Resultados: el embarazo genera en la adolescente sentimientos de displacer relacionados con miedo, tristeza, dolor, sufrimiento, culpa, vergüenza y decepción, acompañados de ideas de negación, evasión, duda, arrepentimiento y deseos de abortar, los cuales no aparecen cuando la adolescente cuenta con el apoyo de su compañero sentimental o el de sus padres. Conclusión: las adolescentes necesitan apoyo, comprensión y ayuda, dado que están más sensibles, lábiles, inseguras y con baja autoestima, situación que requiere que el equipo de salud desarrolle y muestre competencias en el área humanística, acercamiento personal, empatía y trato humanizado e individualizado en la atención de la población de adolescentes embarazadas.

  7. Molecular-based electronically switchable tunnel junction devices.

    Science.gov (United States)

    Collier, C P; Jeppesen, J O; Luo, Y; Perkins, J; Wong, E W; Heath, J R; Stoddart, J F

    2001-12-19

    Solid-state tunnel junction devices were fabricated from Langmuir Blodgett molecular monolayers of a bistable [2]catenane, a bistable [2]pseudorotaxane, and a single-station [2]rotaxane. All devices exhibited a (noncapacitive) hysteretic current-voltage response that switched the device between high- and low-conductivity states, although control devices exhibited no such response. Correlations between the structure and solution-phase dynamics of the molecular and supramolecular systems, the crystallographic domain structure of the monolayer film, and the room-temperature device performance characteristics are reported. PMID:11741428

  8. [Spectroscopic study of diazepam molecularly imprinted polymers and initiative application to conductimetric sensor based on molecularly imprinted films].

    Science.gov (United States)

    Liu, Xiao-fang; Li, Feng; Yao, Bing; Wang, Li; Liu, Guo-yan; Chai, Chun-yan

    2010-08-01

    The molecularly imprinted polymers were synthesized using diazepam as the template and molecularly imprinted films (MIF) prepared on screen printed electrodes (SPE). The binding mechanism and recognition characteristics of the molecularly imprinted polymers were studied by ultraviolet (UV) spectra and infrared (IR) spectra. In addition, a conductimetric sensor for diazepam was established preliminarily based on diazepam MIF modified SPE. The results of UV spectra indicated that template molecules and functional monomers had formed 1:2 hydrogen bonding complexes; the results of IR spectra showed that there were some functional groups in the molecularly imprinted polymers which could interact with the template molecules. The molecularly imprinted polymers manifested highly recognition to diazepam. The response of the conductimetric sensor to the concentration of diazepam displayed a linear correlation over a range of 0.04 to 0.62 mg x L(-1) with a detection limit of 0.008 mg x L(-1). The sensor is suitable for on-the-spot detection of diazepam. PMID:20939345

  9. Molecular Similarity Based on Super-Ball Algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The molecular similarity of 139 organic compounds was calculated by the topologic index method, the flexible super-ball algorithm was used to scan similar molecules and structures. The results show that the properties of organic compounds estimated from this method are reliable.

  10. Experiencia en la evaluación de impacto ambiental de carreteras

    Directory of Open Access Journals (Sweden)

    Villarino Valdivieso, Teresa

    1993-08-01

    Full Text Available This article reviews technical and administrative problems to be dealt with in Spain in the application of the procedure of Environmental Impact Assessment based on the experience of the last five years. Special attention is paid to main road infrastructures.

    El presente artículo pasa revista a los problemas técnicos y administrativos que presenta en España la aplicación del procedimiento de Evaluación del Impacto Ambiental en base a la experiencia acumulada durante los últimos cinco años. Se presta especial atención al caso de las grandes infraestructuras viarias.

  11. Experiencia en la evaluación de impacto ambiental de carreteras

    OpenAIRE

    Villarino Valdivieso, Teresa

    1993-01-01

    This article reviews technical and administrative problems to be dealt with in Spain in the application of the procedure of Environmental Impact Assessment based on the experience of the last five years. Special attention is paid to main road infrastructures.

    El presente artículo pasa revista a los problemas técnicos y administrativos que presenta en España la aplicación del procedimiento de Evaluación del Impacto Ambiental en base a la experiencia acumulada durante los últ...

  12. Molecular Gastronomy: A Food Fad or an Interface for Science-based Cooking?

    OpenAIRE

    Linden, van der, M.; McClements, D.J.; Ubbink, J.

    2008-01-01

    A review is given over the field of molecular gastronomy and its relation to science and cooking. We begin with a brief history of the field of molecular gastronomy, the definition of the term itself, and the current controversy surrounding this term. We then highlight the distinction between molecular gastronomy and science-based cooking, and we discuss both the similarities and the distinctions between science and cooking. In particular, we highlight the fact that the kitchen serves as an i...

  13. Effect of molecular electrical doping on polyfuran based photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuwen; Opitz, Andreas; Salzmann, Ingo, E-mail: ingo.salzmann@physik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, Brook-Taylor Straße 6, 12489 Berlin (Germany); Frisch, Johannes [Helmholtz-Zentrum für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Cohen, Erez; Bendikov, Michael [Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot (Israel); Koch, Norbert [Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, Brook-Taylor Straße 6, 12489 Berlin (Germany); Helmholtz-Zentrum für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Straße 15, 12489 Berlin (Germany)

    2015-05-18

    The electronic, optical, and morphological properties of molecularly p-doped polyfuran (PF) films were investigated over a wide range of doping ratio in order to explore the impact of doping in photovoltaic applications. We find evidence for integer-charge transfer between PF and the prototypical molecular p-dopant tetrafluoro-tetracyanoquinodimethane (F4TCNQ) and employed the doped polymer in bilayer organic solar cells using fullerene as acceptor. The conductivity increase in the PF films at dopant loadings ≤2% significantly enhances the short-circuit current of photovoltaic devices. For higher doping ratios, however, F4TCNQ is found to precipitate at the heterojunction between the doped donor polymer and the fullerene acceptor. Ultraviolet photoelectron spectroscopy reveals that its presence acts beneficial to the energy-level alignment by doubling the open-circuit voltage of solar cells from 0.2 V to ca. 0.4 V, as compared to pristine PF.

  14. Molecular evaluations of thirty one clones of poplar based on RAPD and SSR molecular markers

    Directory of Open Access Journals (Sweden)

    Singh M.K.

    2014-01-01

    Full Text Available Poplar is an important tree species valued all over the world for its wood importance. Despite limited knowledge of the levels of genetic diversity and relatedness, their cultivation as a source of plywood is widespread. In order to facilitate reasoned scientific decisions on its management and conservation and prepare for selective breeding programme, genetic analysis of 31 genotypes was performed using RAPD and SSR molecular markers. Twenty six RAPD primers and 14 SSR primers amplified a total of 236 and 85 scoreable bands of which 86.44% and 86.02% were polymorphic. The mean coefficient of gene differentiation (Gst was 0.388 and 0.341 indicating that 61.2% and 65.9% of the genetic variation resided within the populations. Analysis of molecular variance (AMOVA indicated that majority of genetic variation (94.6% using RAPD and 89% using SSR occurred among genotypes, while the variation between the three groups (categorized as tall, medium and small plants height was 5.4% (using RAPD and 11% (using SSR. The dendrogram obtained from NJ and STRUCTURE analysis revealed splitting of genotypes into four clusters with clear distinction between short, medium and tall height genotypes, indicated that genetic differentiations measure with respect to RAPD and SSR. However, both the markers were equally useful in providing some understanding about the genetic relationship of different genotypes of poplar that are important in the conservation and exploitation of poplar genetic resources.

  15. Choline metabolism-based molecular diagnosis of cancer: an update

    OpenAIRE

    Glunde, Kristine; Penet, Marie-France; Jiang, Lu; Jacobs, Michael A.; Zaver M Bhujwalla

    2015-01-01

    Abnormal choline metabolism continues to be identified in multiple cancers. Molecular causes of abnormal choline metabolism are changes in choline kinase-α, ethanolamine kinase-α, phosphatidylcholine-specific phospholipase C and -D and glycerophosphocholine phosphodiesterases, as well as several choline transporters. The net outcome of these enzymatic changes is an increase in phosphocholine and total choline (tCho) and, in some cancers, a relative decrease of glycerophosphocholine. The incre...

  16. Descifrando las bases moleculares de la resistencia cuantitativa

    OpenAIRE

    Lopez Camilo

    2011-01-01

    Uno de los factores mas importantes que afectan los cultivos son las enfermedades ocasionadas por los patógenos. La resistencia vegetal ha sido clásicamente dividida en dos tipos: i) competa, vertical o cualitativa que es gobernada por un solo gen y ii) incompleta, horizontal o cuantitativa la cual es gobernada por varios genes. Aunque la resistencia cuantitativa provee resistencia de amplio espectro y es durable, los mecanismo moleculares subyacentes no han sido estudiados en detalle. En est...

  17. Electron dopable molecular wires based on the extended viologens

    Czech Academy of Sciences Publication Activity Database

    Kolivoška, Viliam; Gál, Miroslav; Pospíšil, Lubomír; Valášek, Michal; Hromadová, Magdaléna

    2011-01-01

    Roč. 13, č. 23 (2011), s. 11422-11429. ISSN 1463-9076 R&D Projects: GA ČR GA203/08/1157; GA ČR GA203/09/0705; GA AV ČR IAA400400802; GA MŠk(CZ) MEB041006 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : electron transfer * spectroelectrochemistry * molecular wires Subject RIV: CG - Electrochemistry Impact factor: 3.573, year: 2011

  18. Dissecting plasmodesmata molecular composition by mass spectrometry-based proteomics

    OpenAIRE

    Salmon, Magali S.; Bayer, Emmanuelle M. F.

    2013-01-01

    In plants, the intercellular communication through the membranous channels called plasmodesmata (PD; singular plasmodesma) plays pivotal roles in the orchestration of development, defence responses, and viral propagation. PD are dynamic structures embedded in the plant cell wall that are defined by specialized domains of the endoplasmic reticulum (ER) and the plasma membrane (PM). PD structure and unique functions are guaranteed by their particular molecular composition. Yet, up to recent yea...

  19. Molecular Dynamics Simulation of Carbon Nanotube Based Gears

    Science.gov (United States)

    Han, Jie; Globus, Al; Jaffe, Richard; Deardorff, Glenn; Chancellor, Marisa K. (Technical Monitor)

    1996-01-01

    We used molecular dynamics to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. One gear was powered by forcing the atoms near the end of the buckytube to rotate, and a second gear was allowed.to rotate by keeping the atoms near the end of its buckytube on a cylinder. The meshing aromatic gear teeth transfer angular momentum from the powered gear to the driven gear. A number of gear and gear/shaft configurations were simulated. Cases in vacuum and with an inert atmosphere were examined. In an extension to molecular dynamics technology, some simulations used a thermostat on the atmosphere while the hydrocarbon gear's temperature was allowed to fluctuate. This models cooling the gears with an atmosphere. Results suggest that these gears can operate at up to 50-100 gigahertz in a vacuum or inert atmosphere at room temperature. The failure mode involves tooth slip, not bond breaking, so failed gears can be returned to operation by lowering temperature and/or rotation rate. Videos and atomic trajectory files in xyz format are presented.

  20. Comprehensive characterization of molecular interactions based on nanomechanics.

    Directory of Open Access Journals (Sweden)

    Murali Krishna Ghatkesar

    Full Text Available Molecular interaction is a key concept in our understanding of the biological mechanisms of life. Two physical properties change when one molecular partner binds to another. Firstly, the masses combine and secondly, the structure of at least one binding partner is altered, mechanically transducing the binding into subsequent biological reactions. Here we present a nanomechanical micro-array technique for bio-medical research, which not only monitors the binding of effector molecules to their target but also the subsequent effect on a biological system in vitro. This label-free and real-time method directly and simultaneously tracks mass and nanomechanical changes at the sensor interface using micro-cantilever technology. To prove the concept we measured lipid vesicle (approximately 748*10(6 Da adsorption on the sensor interface followed by subsequent binding of the bee venom peptide melittin (2840 Da to the vesicles. The results show the high dynamic range of the instrument and that measuring the mass and structural changes simultaneously allow a comprehensive discussion of molecular interactions.

  1. "Experiencia en la Universidad de Carabobo"

    Directory of Open Access Journals (Sweden)

    Honmy Rosario

    2008-01-01

    Full Text Available Indudablemente la revolución de la tecnología de la información y comunicación (TIC a través de las telecomunicaciones y la informática han cambiando los estilos de vida en esta sociedad del conocimiento. Esto llega a indicar que estas TIC están aquí, y están para perpetuar en el tiempo. Hoy día se convive con el gran desafió que representa el uso de estas TIC en ambientes educativos por ello la necesidad de preparar y actualizar al personal docente de nuestro sector educativo (escuelas, colegios, tecnológicos, universidades, e institutos educacionales para soportar el reto que implica su implementación. La Web es una de las herramientas de estas tecnologías que inducen a implementar cambios importantes en el proceso de enseñanza aprendizaje, específicamente en el desarrollo de trabajos colaborativos. Esta es una estrategia de aprendizaje que se ha expandido en todas las áreas de conocimiento facilitando a todos los actores del proceso (docentes, estudiantes a una alta interacción de información construyendo su propio aprendizaje. El presente trabajo muestra una experiencia del uso de la web como herramienta en el trabajo colaborativo en cursos de "Diseño de Material Computarizado" en pregrado y postgrado en la Universidad de Carabobo y que demuestran la efectividad en el aprendizaje significativo de los tópicos tratados. Se utiliza como estrategia metodológica la creación de un entorno virtual de aprendizaje con el uso de la plataforma nicenet y el desarrollo de páginas web por parte de cada uno de los participantes de los cursos

  2. Rapid Prototyping of Chemical Microsensors Based on Molecularly Imprinted Polymers Synthesized by Two-Photon Stereolithography.

    Science.gov (United States)

    Gomez, Laura Piedad Chia; Spangenberg, Arnaud; Ton, Xuan-Anh; Fuchs, Yannick; Bokeloh, Frank; Malval, Jean-Pierre; Tse Sum Bui, Bernadette; Thuau, Damien; Ayela, Cédric; Haupt, Karsten; Soppera, Olivier

    2016-07-01

    Two-photon stereolithography is used for rapid prototyping of submicrometre molecularly imprinted polymer-based 3D structures. The structures are evaluated as chemical sensing elements and their specific recognition properties for target molecules are confirmed. The 3D design capability is exploited and highlighted through the fabrication of an all-organic molecularly imprinted polymeric microelectromechanical sensor. PMID:27145145

  3. Graph of atomic orbitals and the molecular structure-descriptors based on it

    Directory of Open Access Journals (Sweden)

    ANDREY A. TOROPOV

    2005-04-01

    Full Text Available The graph of atomic orbitals (GAO is a novel type of molecular graph, recently proposed by one of the authors. Various molecular structure-descriptors computed for GAO are compared with their analogs computed for ordinary molecular graphs. The quality of these structure-descriptors was tested for correlation with the normal boiling points of alkanes and cycloalkanes. In all the studied cases, the results based on GAO are similar to, and usually slightly better than, those obtained by means of ordinary molecular graps.

  4. Molecular recognition of α-cyclodextrin (CD) to choral amino acids based on methyl orange as a molecular probe

    Science.gov (United States)

    Yuexian, Fan; Yu, Yang; Shaomin, Shuang; Chuan, Dong

    2005-03-01

    The molecular recognition interaction of α-CD to chiral amino acids was investigated by using spectrophotometry based on methyl orange as a molecular probe. The molecular recognition ability depended on the inclusion formation constants. The molecular recognition of α-CD to aromatic amino acids was the order: DL-tryptophan > L-tryptophan > L-phenylalanine > L-tyrosine ≈ DL-β-3,4-dihydroxy-phenylalanine; whereas for aliphatic amino acids, the order was: L- iso-leucine > L-leucine ≈ L-methionine ≈ DL-mehtionine > D-leucine. The effect of temperature on the inclusion interaction was examined and the thermodynamic parameters of inclusion process, Δ G, Δ H, Δ S, were determined. The experimental results indicated that the inclusion process was an exothermic and enthalpy-driven process accompanied with a negative or minor positive entropic contribution. The inclusion interaction between α-CD and amino acids satisfied the law of enthalpy-entropy compensation. The compensation temperature was 291 K.

  5. Molecular recognition of alpha-cyclodextrin (CD) to choral amino acids based on methyl orange as a molecular probe.

    Science.gov (United States)

    Yuexian, Fan; Yu, Yang; Shaomin, Shuang; Chuan, Dong

    2005-03-01

    The molecular recognition interaction of alpha-CD to chiral amino acids was investigated by using spectrophotometry based on methyl orange as a molecular probe. The molecular recognition ability depended on the inclusion formation constants. The molecular recognition of alpha-CD to aromatic amino acids was the order: DL-tryptophan > L-tryptophan > L-phenylalanine > L-tyrosine approximately DL-beta-3,4-dihydroxy-phenylalanine; whereas for aliphatic amino acids, the order was: L-iso-leucine > L-leucine approximately L-methionine approximately DL-mehtionine > D-leucine. The effect of temperature on the inclusion interaction was examined and the thermodynamic parameters of inclusion process, delta G, delta H, delta S, were determined. The experimental results indicated that the inclusion process was an exothermic and enthalpy-driven process accompanied with a negative or minor positive entropic contribution. The inclusion interaction between alpha-CD and amino acids satisfied the law of enthalpy-entropy compensation. The compensation temperature was 291 K. PMID:15683802

  6. Espacio EpD: una experiencia de desarrollo profesional docente

    OpenAIRE

    Alba Fernández, Nicolás De; Pineda Alfonso, José Antonio

    2015-01-01

    Describimos una experiencia realizada con un grupo de docentes de diversos niveles educativos: Educación Infantil, Educación Primaria, Educación Secundaria y Universidad, que, a través de un Proyecto de la ONG “Madre Coraje” han desarrollado un proceso de aprendizaje cooperativo en una plataforma digital para compartir experiencias en el diseño y experimentación de propuestas didácticas sobre Educación para el Desarrollo (ED). Entre los resultados destacamos las posibilidades q...

  7. El CV de un nadador desconocido: relatos y experiencias

    OpenAIRE

    Milito, Carlos

    2011-01-01

    El objetivo de la ponencia es relatar las experiencias relacionadas con el aprendizaje de la natación y la necesidad de comprobar si podía mantenerme a flote y recorrer metros en el agua, sin la pretensión de competir con otros, sino conmigo mismo. Esas experiencias están intensamente asociadas con el deseo de aprender a nadar y de cómo esa práctica se incorpora a la vida cotidiana. Para conseguir el objetivo, es necesario establecer un recorrido arbitrario; infancia, escuela primaria y depor...

  8. FITOMEJORAMIENTO Y PARTICIPACION LOCAL. UNA EXPERIENCIA EN CUBA

    OpenAIRE

    Lucy Martin; H. Ríos; Gladys Verde; M. Ponce; Ortiz, R.; Sandra Miranda; Rosa Acosta

    2003-01-01

    Este artículo examina, desde una perspectiva so- cial, las experiencias de trabajo que un equipo multidisciplinario del INCA lleva a cabo en tres cooperativas de producción agropecuaria (CPA) del sur de La Habana y en una cooperati- va de créditos y servicios (CCS) de La Palma, Pinar del Río, con el objetivo de encontrar vías complementarias del fitomejoramiento formal por la vía participativa, se pretende destacar cómo en una experiencia de fitomejoramiento con la participación de los produc...

  9. Antes de los Estudios Culturales. Robert Warshow y la experiencia

    OpenAIRE

    Antonio Lastra

    2008-01-01

    Este artículo estudia la influencia del concepto de experiencia que desarrolla Robert Warshow. Warshow ha supuesto el contrapunto americano a las teorías desarrolladas por Walter Benjamien en Europa. Si bien ambos insistieron en la pobreza de la experiencia, como resultado de la tecnificación de la sociedad, Warshow supo introducir matizaciones que influyeron en todo el círculo de intelectuales concentrados en Nueva York durante la etapa de consolidación de los Estudios Culturales. This paper...

  10. On-chip molecular electronic plasmon sources based on self-assembled monolayer tunnel junctions

    Science.gov (United States)

    Du, Wei; Wang, Tao; Chu, Hong-Son; Wu, Lin; Liu, Rongrong; Sun, Song; Phua, Wee Kee; Wang, Lejia; Tomczak, Nikodem; Nijhuis, Christian A.

    2016-04-01

    Molecular electronic control over plasmons offers a promising route for on-chip integrated molecular plasmonic devices for information processing and computing. To move beyond the currently available technologies and to miniaturize plasmonic devices, molecular electronic plasmon sources are required. Here, we report on-chip molecular electronic plasmon sources consisting of tunnel junctions based on self-assembled monolayers sandwiched between two metallic electrodes that excite localized plasmons, and surface plasmon polaritons, with tunnelling electrons. The plasmons originate from single, diffraction-limited spots within the junctions, follow power-law distributed photon statistics, and have well-defined polarization orientations. The structure of the self-assembled monolayer and the applied bias influence the observed polarization. We also show molecular electronic control of the plasmon intensity by changing the chemical structure of the molecules and by bias-selective excitation of plasmons using molecular diodes.

  11. Molecular group dynamics study on slip flow of thin fluid film based on the Hamaker hypotheses

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The thin fluid film was assumed to consist of a number of spherical fluid molecular groups and the attractive forces of molecular group pairs were calculated by the derived equation according to the three Hamaker homogeneous material hypotheses. Regarding each molecular group as a dynamics individual, the simulation method for the shearing motion of multilayer fluid molecular groups, which was initiated by two moving walls, was proposed based on the Verlet velocity iterative algorithm. The simulations reveal that the velocities of fluid molecular groups change about their respective mean velocities within a narrow range in steady state. It is also found that the velocity slips occur at the wall boundary and in a certain number of fluid film layers close to the wall. Because the dimension of molecular group and the number of group layers are not restricted, the hypothetical thickness of fluid film model can be enlarged from nanometer to micron by using the proposed simulation method.

  12. Molecular dynamics computer simulations based on NMR data

    International Nuclear Information System (INIS)

    In the work described in this thesis atom-atom distance information obtained from two-dimensional cuclear magnetic resonance is combined with molecular dynamics simulaitons. The simulation is used to improve the accuracy of a structure model constructed on the basis of NMR data. During the MD refinement the crude NMR structure is simultaneously optimized with respect to the atomic interaction function and to the set of atom-atom distances or other NMR information. This means that insufficient experimental data is completed with theoretical knowledge and the combination will lead to more reliable structures than would be obtained from one technique alone. (author). 191 refs.; 17 figs.; 12 schemes; 22 tabs

  13. Del mercado a la academia: de la experiencia empresarial a la experiencia en la docencia universitaria

    Directory of Open Access Journals (Sweden)

    Monica Bonifaz

    2012-12-01

    Full Text Available En este artículo se analizan las posibles contribuciones de la experiencia profesional empresarial para el ámbito académico. Expone algunas oportunidades y prácticas de gestión que, sin afectar la misión y la razón de ser de la Universidad, pueden trasladarse del modelo empresarial a las diferentes funciones y roles que desempeña la Universidad, y contribuir con una gestión más eficiente y eficaz de los recursos disponibles en beneficio de la generación y transferencia del conocimiento, y del logro de los resultados académicos esperados.

  14. Vibrational Spectra of Molecular Crystals with the Generalized Energy-Based Fragmentation Approach.

    Science.gov (United States)

    Fang, Tao; Jia, Junteng; Li, Shuhua

    2016-05-01

    The generalized energy-based fragmentation (GEBF) approach for molecular crystals with periodic boundary condition (PBC) (denoted as PBC-GEBF) is extended to allow vibrational spectra of molecular crystals to be easily computed at various theory levels. Within the PBC-GEBF approach, the vibrational frequencies of a molecular crystal can be directly evaluated from molecular quantum chemistry calculations on a series of nonperiodic molecular systems. With this approach, the vibrational spectra of molecular crystals can be calculated with much reduced computational costs at various theory levels, as compared to those required by the methods based on periodic electronic structure theory. By testing the performance of the PBC-GEBF method for two molecular crystals (CO2 and imidazole), we demonstrate that the PBC-GEBF approach can reproduce the results of the methods based on periodic electronic structure theory in predicting vibrational spectra of molecular crystals. We apply the PBC-GEBF method at second-order Møller-Plesset perturbation theory (PBC-GEBF-MP2 in short) to investigate the vibrational spectra of the urea and ammonia borane crystals. Our results show that the PBC-GEBF-MP2 method can provide quite accurate descriptions for the observed vibrational spectra of the two systems under study. PMID:27076120

  15. Novel Metal Ion Based Estrogen Mimics for Molecular Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopalan, Raghavan

    2006-01-30

    The overall objective of the SBIR Phase I proposal is to prepare and evaluate a new class of {sup 99m}Tc or {sup 94m}Tc containing estrogen-like small molecules ('estrogen mimics') for SPECT or PET molecular imaging of estrogen receptor positive (ER+) tumors. In this approach, the metal ion is integrated into the estrone skeleton by isosteric substitution of a carbon atom in the steroidal structure to give new class of mimics that are topologically similar to the native estrogen (Fig. 1). Although both N{sub 2}S{sub 2} and N{sub 3}S mimics 1 and 2 were considered as target structures, molecular modeling study revealed that the presence of the acetyl group at position-15 in the N{sub 3}S mimic 2 causes steric hinderance toward binding of 2 to SHBG. Therefore, initial efforts were directed at the synthesis and evaluation of the N{sub 2}S{sub 2} mimic 1.

  16. Fishing the molecular bases of Treacher Collins syndrome.

    Directory of Open Access Journals (Sweden)

    Andrea M J Weiner

    Full Text Available Treacher Collins syndrome (TCS is an autosomal dominant disorder of craniofacial development, and mutations in the TCOF1 gene are responsible for over 90% of TCS cases. The knowledge about the molecular mechanisms responsible for this syndrome is relatively scant, probably due to the difficulty of reproducing the pathology in experimental animals. Zebrafish is an emerging model for human disease studies, and we therefore assessed it as a model for studying TCS. We identified in silico the putative zebrafish TCOF1 ortholog and cloned the corresponding cDNA. The derived polypeptide shares the main structural domains found in mammals and amphibians. Tcof1 expression is restricted to the anterior-most regions of zebrafish developing embryos, similar to what happens in mouse embryos. Tcof1 loss-of-function resulted in fish showing phenotypes similar to those observed in TCS patients, and enabled a further characterization of the mechanisms underlying craniofacial malformation. Besides, we initiated the identification of potential molecular targets of treacle in zebrafish. We found that Tcof1 loss-of-function led to a decrease in the expression of cellular proliferation and craniofacial development. Together, results presented here strongly suggest that it is possible to achieve fish with TCS-like phenotype by knocking down the expression of the TCOF1 ortholog in zebrafish. This experimental condition may facilitate the study of the disease etiology during embryonic development.

  17. PET-based molecular nuclear neuro-imaging

    International Nuclear Information System (INIS)

    Molecular nuclear neuro-imaging in CNS drug discovery and development can be divided into four categories that are clearly inter-related. (1) Neuroreceptor mapping to examine the involvement of specific neurotransmitter system in CNS diseases, drug occupancy characteristics and perhaps examine mechanisms of action;(2) Structural and spectroscopic imaging to examine morphological changes and their consequences;(3) Metabolic mapping to provide evidence of central activity and CNS fingerprinting the neuroanatomy of drug effects;(4) Functional mapping to examine disease-drug interactions. In addition, targeted delivery of therapeutic agents could be achieved by modifying stem cells to release specific drugs at the site of transplantation('stem cell pharmacology'). Future exploitation of stem cell biology, including enhanced release of therapeutic factors through genetic stem cell engineering might thus constitute promising pharmaceutical approaches to treating diseases of the nervous system. With continued improvements in instrumentation, identification of better imaging probes by innovative chemistry, molecular nuclear neuro-imaging promise to play increasingly important roles in disease diagnosis and therapy

  18. Geometría para futuros profesores de primaria: experiencias con el tangram chino

    OpenAIRE

    Fernández, Teresa

    2003-01-01

    Este artículo tiene como objetivo presentar una experiencia sobre didáctica de la geometría llevada a cabo en la facultad de Ciencias de la Educación de Santiago de Compostela con alumnos de la especialidad de maestro en educación primaria. En ella se utilizó un juego de disección (el tangram chino) como base para la realización de una serie de actividades que tienen un objetivo múltiple: concienciar a los alumnos sobre las ventajas del uso de un material manipulativo para el estudio de propi...

  19. Relaciones entre la experiencia exportadora y el desempeño productivo de la industria colombiana

    OpenAIRE

    López Soler Ramiro

    2006-01-01

    En los últimos años se han escrito diversos trabajos que estudian el impacto de las exportaciones sobre la productividad de las empresas colombianas. Sin embargo, los diferentes estudios no han podido utilizar información posterior a 1994, por cambios metodológicos en las fuentes de información. Este trabajo ofrece una solución al problema antes mencionado, construyendo una base de datos sobre la experiencia exportadora de las empresas manufactureras para el período 1992-2002. Adicionalmente,...

  20. Tumores de células germinales del mediastino: Experiencia con 29 pacientes

    OpenAIRE

    José A Mainieri-Hidalgo; Valeria Rees-Alpízar; Isabel Gamboa-González; Marcelo Mainieri-Breedy

    2013-01-01

    Objetivo: revisar e informar la experiencia adquirida con el manejo de tumores de células germinales del mediastino, en el Hospital Calderón Guardia. Metodología: previa autorización del Comité de Ética del Hospital, se realizó un análisis descriptivo de la información acumulada en la base de datos del Servicio de Cirugía de Tórax y los expedientes clínicos de 29 pacientes con tumores de células germinales del mediastino, operados entre 1986 y 2012. Resultados: se encontró mayor frecuencia en...

  1. Analysis of Connectivity in Diffusion-Based Molecular Nano Communication Networks

    OpenAIRE

    Fereidouni, Arash

    2013-01-01

    ABSTRACT: A nanonetwork is an interconnection of nano devices that are made up of nano-scale components. Several approaches for designing and implementing nanonetworks have been presented in recent years. Diffusion-based molecular communication is one of these approaches that use molecules as means of transmitting information in network. In diffusion-based molecular communication, molecules or particles diffuse in an aqueous environment under Fick’s laws of diffusion to move from transmitter ...

  2. Electronic Transport Properties of a Naphthopyran-Based Optical Molecular Switch:an ab initio Study

    Institute of Scientific and Technical Information of China (English)

    XIA Cai-Juan; LIU De-Sheng; ZHANG Ying-Tang

    2011-01-01

    The electronic transport properties of a. Naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's Function formalism combined with first-principles density functional theory. The molecule that comprises the switch can convert between its open and closed forms upon photoexcitation. Theoretical results show that the current through the open form is significantly larger than that through the closed form, which is different from other optical switches based on ring-opening reactions of the molecular bridge. The maximum on-off ratio (about 90) can be obtained at 1.4 V. The physical origin of the switching behavior is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap. Our result shows that the naphthopyran-based molecule is a good candidate for optical molecular switches and will be useful in the near future.%@@ ronic transport properties of a naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's function formalism combined with first-principles density functional theory.The molecule that comprises the switch can convert between its open and closed forms upon photoexcitation.Theoretical results show that the current through the open form is significantly larger than that through the closed form,which is different from other optical switches based on ring-opening reactions of the molecular bridge.The maximum on-off ratio(about 90)can be obtained at 1.4 V.The physical origin of the switching behavior is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap.Our result shows that the naphthopyran-based molecule is a good candidate for optical molecular switches and will be useful in the near future.

  3. Generadores automáticos y gramática funcional Inglesa: una experiencia de integración en el aula virtual

    OpenAIRE

    Lavid López, María Julia; Zamorano Mansilla, Juan Rafael

    2005-01-01

    El propósito de este trabajo es describir una experiencia de integración en el aula virtual de un sistema computacional de desarrollo de gramáticas para la generación automática (Komet Penman Multilingual, KPML), típicamente utilizado para la investigación, como base para la exploración dinámica de la gramática funcional inglesa. La experiencia se desarrolló como parte de las actividades didácticas de la asignatura de Lingüística Computacional dentro del plan de estudios de Filolo...

  4. Genetic diversity analysis of common beans based on molecular markers

    Directory of Open Access Journals (Sweden)

    Homar R. Gill-Langarica

    2011-01-01

    Full Text Available A core collection of the common bean (Phaseolus vulgaris L., representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each, as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP +3/+3 primer combinations and seven simple sequence repeats (SSR loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA and molecular variance (AMOVA analyses. AFLP analysis produced 530 bands (88.5% polymorphic while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus. AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation.

  5. Clinicopathological and Molecular Histochemical Review of Skull Base Metastasis from Differentiated Thyroid Carcinoma

    International Nuclear Information System (INIS)

    Skull base metastasis from differentiated thyroid carcinoma including follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC) is a rare clinical entity. Eighteen FTC cases and 10 PTC cases showing skull base metastasis have been reported. The most common symptom of skull base metastasis from FTC and PTC is cranial nerve dysfunction. Bone destruction and local invasion to the surrounding soft tissues are common on radiological imaging. Skull base metastases can be the initial clinical presentation of FTC and PTC in the presence of silent primary sites. The possibility of skull base metastasis from FTC and PTC should be considered in patients with the clinical symptoms of cranial nerve dysfunction and radiological findings of bone destruction. A variety of genetic alterations in thyroid tumors have been identified to have a fundamental role in their tumorigenesis. Molecular histochemical studies are useful for elucidating the histopathological features of thyroid carcinoma. Recent molecular findings may provide novel molecular-based treatment strategies for thyroid carcinoma

  6. Experiencia con la acreditación ACTIC

    OpenAIRE

    Trench, Joan; Canto, Carme

    2011-01-01

    Esta comunicación presenta a experiencia da acreditación ACTIC na Universitat Pompeu Fabra. Relatorio presentado nas IX Jornadas CRAI "Evaluación y acreditación de las competencias informáticas e informacionales", Universidade de Santiago de Compostela, 16-17 de xuño de 2011

  7. Experiencia con la acreditación ECDL

    OpenAIRE

    Fernández Sanz, Luis

    2011-01-01

    Esta ponencia presenta a experiencia da acreditación ECDL (European Computer Driving Licence) na Universidad de Alcalá. Relatorio presentado nas IX Jornadas CRAI "Evaluación y acreditación de las competencias informáticas e informacionales", Universidade de Santiago de Compostela, 16-17 de xuño de 2011

  8. Tip-induced gating of molecular levels in carbene-based junctions.

    Science.gov (United States)

    Foti, Giuseppe; Vázquez, Héctor

    2016-03-29

    We study the conductance of N-heterocyclic carbene-based (NHC) molecules on gold by means of first-principles calculations based on density-functional theory and non-equilibrium Green's functions. We consider several tip structures and find a strong dependence of the position of the NHC molecular levels with the atomistic structure of the tip. The position of the lowest unoccupied molecular orbital (LUMO) can change by almost 0.8 eV with tip shape. Through an analysis of the net charge transfer, electron redistribution and work function for each tip structure, we rationalize the LUMO shifts in terms of the sum of the work function and the maximum electrostatic potential arising from charge rearrangement. These differences in the LUMO position, effectively gating the molecular levels, result in large conductance variations. These findings open the way to modulating the conductance of NHC-based molecular circuits through the controlled design of the tip atomistic structure. PMID:26891059

  9. A new graph-based molecular descriptor using the canonical representation of the molecule.

    Science.gov (United States)

    Hentabli, Hamza; Saeed, Faisal; Abdo, Ammar; Salim, Naomie

    2014-01-01

    Molecular similarity is a pervasive concept in drug design. The basic idea underlying molecular similarity is the similar property principle, which states that structurally similar molecules will exhibit similar physicochemical and biological properties. In this paper, a new graph-based molecular descriptor (GBMD) is introduced. The GBMD is a new method of obtaining a rough description of 2D molecular structure in textual form based on the canonical representations of the molecule outline shape and it allows rigorous structure specification using small and natural grammars. Simulated virtual screening experiments with the MDDR database show clearly the superiority of the graph-based descriptor compared to many standard descriptors (ALOGP, MACCS, EPFP4, CDKFP, PCFP, and SMILE) using the Tanimoto coefficient (TAN) and the basic local alignment search tool (BLAST) when searches were carried. PMID:25140330

  10. Tetracycline selective electrode based on molecularly imprinted polymer particles

    Institute of Scientific and Technical Information of China (English)

    Zhi Yong Guo; Pan Pan Gai; Jing Duan; Hui Na Zhang; Sui Wang

    2010-01-01

    Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time,and its performance was carefully characterized.Due to the specific recognition of tetracycline by the particles,the selectivity coefficients for routine interferences were less than 10-4.Benefited from the absence of tetracycline in the sensitive membrane and the optimized composition of the inner filling solution,the limit of detection of the electrode was reduced to about 2.5 × 10-8 mol/L.It exhibited a good electrode slope 57.6 mV/decade near the theoretical Nernstian one,with a wide linear working range from6.0 × 10-8 to 1.0 × 10-3 mol/L.The fabricated electrode should be used in pH 2-4,response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0 × 10-6 mol/L and no more than 30 min at the concentration of1.0 × 10-8 mol/L.

  11. Descifrando las bases moleculares de la resistencia cuantitativa

    Directory of Open Access Journals (Sweden)

    Lopez Camilo

    2011-08-01

    Full Text Available Uno de los factores mas importantes que afectan los cultivos son las enfermedades ocasionadas por los patógenos. La resistencia vegetal ha sido clásicamente dividida en dos tipos: i competa, vertical o cualitativa que es gobernada por un solo gen y ii incompleta, horizontal o cuantitativa la cual es gobernada por varios genes. Aunque la resistencia cuantitativa provee resistencia de amplio espectro y es durable, los mecanismo moleculares subyacentes no han sido estudiados en detalle. En esta revisión se propone un modelo basado en la co-localización de genes similares a los clásicos genes de resistencia cualitativa con QTLs (Quantitative Trait Loci para explicar el mecanismo involucrado en el reconocimiento del patógeno durante la resistencia cuantitativa. Además se presenta información acerca del progreso obtenido en los últimos tres años para entender este tipo de resistencia, que culminó con la clonación de varios genes asociados a la resistencia cuantitativa. En conjunto, estos datos proveen nuevas luces sobre la naturaleza genética de este tipo de resistencia y de cómo puede ser empleada en programas de mejoramiento genético.

  12. Molecular self assembly on optical fiber-based fluorescence sensor

    Science.gov (United States)

    Ayyagari, Madhu S. R.; Gao, Harry H.; Bihari, Bipin; Chittibabu, Kethinni G.; Kumar, Jayant; Marx, Kenneth A.; Kaplan, David L.; Tripathy, Sukant K.

    1994-03-01

    We discuss the molecular self-assembly on optical fibers in which a novel method for protein attachment to the sensing tip of the fiber is used. Our objective is to assemble a conjugated polythiophene copolymer as an attachment vehicle. Subsequent attachment of the photodynamic phycobiliprotein serves as the fluorescence probe element. Following our earlier experiments from Langmuir-Blodgett deposition of these polymeric materials as thin films on glass substrates, we extended the technique to optical fibers. First, the bare fiber surface is silanized with a C18 silane compound. The copolymer (3-undecylthiophene-co-3- methanolthiophene, biotinylated at the methanol moiety) assembly on the fiber is carried out presumable through van der Waals interactions between the hydrophobic fiber surface and the undecyl alkyl chains on the polymer backbone. A conjugated Str-PE (streptavidin covalently attached to phycoerythrin) complex is then attached to the copolymer via the conventional biotin-streptavidin interaction. The conjugated polymer not only supports the protein but, in principle, may help to transduce the signal generated by phycoerythrin to the fiber. Our results from fluorescence intensity measurements proved the efficacy of this system. An improved methodology is also sought to more strongly attach the conjugated copolymer to the fiber surface, and a covalent scheme is developed to polymerize and biotinylate polythiophene in situ on the fiber surface.

  13. La experiencia del proyecto EMILIA en Barcelona. El usuario como experto: concepto, modalidades y experiencia desde el Proyecto Emilia.

    Directory of Open Access Journals (Sweden)

    Paz Flores

    2010-01-01

    Full Text Available Se relata la experiencia del proyecto EMILIA y se ofrece una visión global de qué se entiende por “usuario experto” y “implicación de los usuarios” en salud mental. Se discuten sus implicaciones para los profesionales, usuarios y el sistema sanitario.

  14. La experiencia del proyecto EMILIA en Barcelona. El usuario como experto: concepto, modalidades y experiencia desde el Proyecto Emilia.

    OpenAIRE

    Paz Flores; Carmen Masferrer; Eithne Leahy; Roser Izquierdo; Eduard Palomer

    2010-01-01

    Se relata la experiencia del proyecto EMILIA y se ofrece una visión global de qué se entiende por “usuario experto” y “implicación de los usuarios” en salud mental. Se discuten sus implicaciones para los profesionales, usuarios y el sistema sanitario.

  15. EXPERIENCIAS EXTRASENSORIALES Y EXPERIENCIAS ALUCINATORIAS: EXAMINANDO LA HIPÓTESIS DEL CONTINUO DE EXPERIENCIAS ESQUIZOTÍPICAS/ EXTRASENSORIAL AND HALLUCINATORY EXPERIENCES: EXAMINING THE CONTINUOUS THEORY ON SCHIZOTYPAL EXPERIENCES

    Directory of Open Access Journals (Sweden)

    Alejandro Parra*

    2010-05-01

    Full Text Available RESUMENUna experiencia extrasensorial es aquella en la que parece que la mente de una persona ha adquirido la informaciónremota, es decir, aparentemente sin la mediación de los sentidos humanos conocidos o procesos de inferencia lógica. Portanto, lo «extrasensorial» en la experiencia extrasensorial corresponde a juzgar por las apariencias y no necesariamente a larealidad, mientras que lo «extrasensorial» en la percepcion extrasensorial se refiere a la naturaleza de una presunta realidadparanormal. Se ponen a prueba dos hipótesis específicas: Una muestra de estudiantes argentinos que reportan haber tenidoexperiencias extrasensoriales tienen mayor capacidad de experimentar (1 alucinaciones visuales y táctiles, y (2 propensióna la esquizotipia en comparación con quienes no tuvieron experiencias extrasensoriales. Los resultados mostraron mayornivel de esquizotipia cognitivo-perceptual y propensión a la alucinación en individuos con experiencias que quienes no lastuvieron. Los resultados sugieren que hay procesos disociativos subyacentes, como absorción y propensión a la fantasía,que parecen estar asociadas a las experiencias extrasensoriales.ABSTRACTAn extrasensory experience is one in which it appears that the experient’s mind has acquired information directly, thatis, seemingly without either the mediation of the recognized human senses or the processes of logical inference. The«extrasensory» in extrasensory experience therefore pertains to appearances and not necessarily to reality, whereas the«extrasensory» in extrasensory perception refers to the nature of a hypothesized paranormal reality. Two specific hypothesesare tested: A sample of Argentinean participants who have reported Extrasensorial experiences have a higher capacity for (1visual and tactile hallucination, and (2 schizotypy proneness than non--experients. The results showed a higher level ofcognitive-perceptual schizotypy and hallucination proneness in

  16. [Molecular engineering of cellulase catalytic domain based on glycoside hydrolase family].

    Science.gov (United States)

    Zhang, Xiaomei; Li, Dandan; Wang, Lushan; Zhao, Yue; Chen, Guanjun

    2013-04-01

    Molecular engineering of cellulases can improve enzymatic activity and efficiency. Recently, the Carbohydrate-Active enZYmes Database (CAZy), including glycoside hydrolase (GH) families, has been established with the development of Omics and structural measurement technologies. Molecular engineering based on GH families can obviously decrease the probing space of target sequences and structures, and increase the odds of experimental success. Besides, the study of cellulase active-site architecture paves the way toward the explanation of catalytic mechanism. This review focuses on the main GH families and the latest progresses in molecular engineering of catalytic domain. Based on the combination of analysis of a large amount of data in the same GH family and their conservative active-site architecture information, rational design will be an important direction for molecular engineering and promote the rapid development of the conversion of biomass. PMID:23894816

  17. Large magnetoresistance of paracyclophane-based molecular tunnel junctions: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Tao, L. L.; Liang, S. H.; Liu, D. P.; Han, X. F., E-mail: xfhan@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2013-12-07

    We report a theoretical study of magnetoresistance and spin-polarized transport of a series of paracyclophane-based molecular tunnel junctions. We predict that the molecular tunnel junction using [2.2]-paracyclophane barrier has the desired low resistance area product in combination with high magnetoresistance ratio. In addition, we find the spin-polarized conductance decreases exponentially with increasing the molecular length, indicating a nonresonant tunneling mechanism. In particular, the characteristic decay constant can be theoretically evaluated from the complex band structure of periodic paracyclophane molecule. The spin-polarized transport mechanism is systematically analyzed.

  18. Large magnetoresistance of paracyclophane-based molecular tunnel junctions: A first-principles study

    International Nuclear Information System (INIS)

    We report a theoretical study of magnetoresistance and spin-polarized transport of a series of paracyclophane-based molecular tunnel junctions. We predict that the molecular tunnel junction using [2.2]-paracyclophane barrier has the desired low resistance area product in combination with high magnetoresistance ratio. In addition, we find the spin-polarized conductance decreases exponentially with increasing the molecular length, indicating a nonresonant tunneling mechanism. In particular, the characteristic decay constant can be theoretically evaluated from the complex band structure of periodic paracyclophane molecule. The spin-polarized transport mechanism is systematically analyzed

  19. Foraging on the potential energy surface: A swarm intelligence-based optimizer for molecular geometry

    Science.gov (United States)

    Wehmeyer, Christoph; Falk von Rudorff, Guido; Wolf, Sebastian; Kabbe, Gabriel; Schärf, Daniel; Kühne, Thomas D.; Sebastiani, Daniel

    2012-11-01

    We present a stochastic, swarm intelligence-based optimization algorithm for the prediction of global minima on potential energy surfaces of molecular cluster structures. Our optimization approach is a modification of the artificial bee colony (ABC) algorithm which is inspired by the foraging behavior of honey bees. We apply our modified ABC algorithm to the problem of global geometry optimization of molecular cluster structures and show its performance for clusters with 2-57 particles and different interatomic interaction potentials.

  20. Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences

    OpenAIRE

    Michelle Klein Sercundes; Samantha Yuri Oshiro Branco Valadas; Lara Borges Keid; Tricia Maria Ferreira Souza Oliveira; Helena Lage Ferreira; Ricardo Wagner Almeida Vitor; Fábio Gregori; Rodrigo Martins Soares

    2016-01-01

    Abstract Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC) and beta subunit of RNA polymerase (rpoB), and mitochondrial gene coding for cytochrome B (cytB) were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula ...

  1. Scope of Tunnel Junction Based Molecular Electronics and Spintronics Devices

    OpenAIRE

    Tyagi, Pawan; Friebe, Edwards; Baker, Collin

    2014-01-01

    Scope of molecule based devices may govern the advancement of the next generation logic and memory devices. Molecules have the potential to be unmatched device elements as chemists can mass produce an endless variety of molecules with novel optical, magnetic, and charge transport characteristics. However, the biggest challenge is to connect two metal leads to a target molecule(s) and develop a robust and versatile device fabrication technology that can be adopted for commercial scale mass pro...

  2. Molecular Engineering of Technetium and Rhenium Based Radiopharmaceuticals

    International Nuclear Information System (INIS)

    The research was based on the observation that despite the extraordinarily rich coordination chemistry of technetium and rhenium and several notable successes in reagent design, the extensive investigations by numerous research groups on a variety of N2S2 and N3S donor type ligands and on HYNIC have revealed that the chemistries of these ligands with Tc and Re are rather complex, giving rise to considerable difficulties in the development of reliable procedures for the development of radiopharmaceutical reagents

  3. Knowledge-Based Optimization of Molecular Geometries Using Crystal Structures.

    Science.gov (United States)

    Cole, Jason C; Groom, Colin R; Korb, Oliver; McCabe, Patrick; Shields, Gregory P

    2016-04-25

    This paper describes a novel way to use the structural information contained in the Cambridge Structural Database (CSD) to drive geometry optimization of organic molecules. We describe how CSD structural information is transformed into objective functions for gradient-based optimization to provide good quality geometries for a large variety of organic molecules. Performance is assessed by minimizing different sets of organic molecules reporting RMSD movements for bond lengths, valence angles, torsion angles, and heavy atom positions. PMID:26977906

  4. Equivalent electric circuit of a carbon nanotube based molecular conductor

    CERN Document Server

    Yam, ChiYung; Wang, Fan; Li, Xiaobo; Chen, GuanHua; Zheng, Xiao; Matsuda, Yuki; Tahir-Kheli, Jamil; Goddard, William A

    2008-01-01

    We apply our first-principles method to simulate the transient electrical response through carbon nanotube based conductors under time-dependent bias voltages, and report the dynamic conductance for a specific system. We find that the electrical response of the carbon nanotube device can be mapped onto an equivalent classical electric circuit. This is confirmed by studying the electric response of a simple model system and its equivalent circuit.

  5. Molecular bases of circadian rhythmicity in renal physiology and pathology

    OpenAIRE

    Bonny, Olivier; Vinciguerra, Manlio; Gumz, Michelle L.; Mazzoccoli, Gianluigi

    2013-01-01

    The physiological processes that maintain body homeostasis oscillate during the day. Diurnal changes characterize kidney functions, comprising regulation of hydro-electrolytic and acid-base balance, reabsorption of small solutes and hormone production. Renal physiology is characterized by 24-h periodicity and contributes to circadian variability of blood pressure levels, related as well to nychthemeral changes of sodium sensitivity, physical activity, vascular tone, autonomic function and neu...

  6. Molecular Phylogenetic: Organism Taxonomy Method Based on Evolution History

    OpenAIRE

    N.L.P Indi Dharmayanti

    2011-01-01

    Phylogenetic is described as taxonomy classification of an organism based on its evolution history namely its phylogeny and as a part of systematic science that has objective to determine phylogeny of organism according to its characteristic. Phylogenetic analysis from amino acid and protein usually became important area in sequence analysis. Phylogenetic analysis can be used to follow the rapid change of a species such as virus. The phylogenetic evolution tree is a two dimensional of a spec...

  7. iBarcode.org: web-based molecular biodiversity analysis

    OpenAIRE

    Hajibabaei Mehrdad; Singer Gregory AC

    2009-01-01

    Abstract Background DNA sequences have become a primary source of information in biodiversity analysis. For example, short standardized species-specific genomic regions, DNA barcodes, are being used as a global standard for species identification and biodiversity studies. Most DNA barcodes are being generated by laboratories that have an expertise in DNA sequencing but not in bioinformatics data analysis. Therefore, we have developed a web-based suite of tools to help the DNA barcode research...

  8. TARGET-ORIENTED GENERIC FINGERPRINT-BASED MOLECULAR REPRESENTATION

    OpenAIRE

    Petr Skoda; David Hoksza

    2014-01-01

    The screening of chemical libraries is an important step in the drug discovery process. The existing chemical libraries contain up to millions of compounds. As the screening at such scale is expensive, the virtual screening is often utilized. There exist several variants of virtual screening and ligand-based virtual screening is one of them. It utilizes the similarity of screened chemical compounds to known compounds. Besides the employed similarity measure, another aspect grea...

  9. DNA Based Carbon Nanotube Porphyrin Nanohybrids Molecular Recognization and Regeneration

    OpenAIRE

    Riccitelli, Molly M; Zhang, Hanyu; Choi, Jong Hyun

    2013-01-01

    In the search to improve solar cells, scientists are exploring new materials that will provide better current transfer. One material that has emerged as a strong contender is the single walled carbon nanotube (SWNT). Current DNA-SWNT based films combined with chromophores have poor operational lifetimes compared to commercial solar cells. Once exposed to light the chromophore begins to degrade, eventually rendering the solar cell unusable. To solve this problem, we used a method involving mul...

  10. Molecular engineering of manipulated alginate-based polyurethanes.

    Science.gov (United States)

    Daemi, Hamed; Barikani, Mehdi

    2014-11-01

    The novel soluble alginate-based polyurethanes in organic solvents were synthesized by the reaction of NCO-terminated prepolymers and tributylammonium alginate (TBA-Alg) for the first time. The chemical structures of synthesized polyurethanes were characterized using FTIR, (1)H NMR and TGA. The reaction completion was confirmed by disappearing of NCO band in FTIR spectra. Furthermore, a peak at 4.71 ppm and some small peaks at a range of 4.12-4.37 ppm in the (1)H NMR of alginate-based polyurethanes were assigned to the backbone of alginate. The results of both FTIR and (1)H NMR were remarkably confirmed by TGA data. The ionic nature of polyurethane backbone not only affects on thermal properties of samples, but it also changes the chemically-bonded alginate morphology. Both polyether and polyester based non-ionic polyurethanes extended by TBA-Alg illustrated the distinct alginate, whereas those ionomers extended by alginate were appeared as the continuous systems at nanoscale. PMID:25129793

  11. The formation of ZnO-based coatings from solutions containing high-molecular polyvinylpyrrolidone

    Science.gov (United States)

    Evstrop'ev, S. K.; Soshnikov, I. P.; Khrebtov, A. I.

    2016-05-01

    A method for deposition of transparent nanosize ZnO-based coatings on the glass surface from solutions containing high-molecular polyvinylpyrrolidone is described. The method can be used to form transparent homogeneous coatings based on ZnO with an increased energy gap width. It does not require any intricate technological equipment.

  12. Molecular dynamics simulation study on capacitive nano-accelerometers based on telescoping carbon nanotubes

    International Nuclear Information System (INIS)

    We investigated the characteristics of a capacitive nano-accelerometer based on a telescoping carbon nanotube by means of classical molecular dynamics simulations. The position of the telescoping nanotube was controlled by an externally applied force, and feedback sensing was based on the capacitance change. The capacitance variations, which were almost linearly proportional to the applied acceleration, were monitored within an error tolerance

  13. Two-dimensional vibrational spectroscopy of rotaxane-based molecular machines.

    Science.gov (United States)

    Bodis, Pavol; Panman, Matthijs R; Bakker, Bert H; Mateo-Alonso, Aurelio; Prato, Maurizio; Buma, Wybren Jan; Brouwer, Albert M; Kay, Euan R; Leigh, David A; Woutersen, Sander

    2009-09-15

    It has recently become possible to synthesize mechanical devices the size of a single molecule. Although it is tempting to regard such molecular machines as nanoscale versions of their macroscopic analogs, many notions from macroscopic mechanics no longer apply at a molecular level. For instance, the concept of viscous friction is meaningless for a molecular machine because the size of the solvent molecules that cause the friction is comparable to that of the machine itself. Furthermore, in many cases, the interactions between a molecular machine and its surroundings are comparable to the force driving the machine. As a result, a certain amount of intrinsic randomness exists in the motion of molecular machines, and the details of their mechanics are largely unknown. For a detailed understanding of the mechanical behavior of molecular machines, experiments that probe their motion on an ultrafast time scale, such as two-dimensional (2D) vibrational spectroscopy, are essential. This method uses coupling between vibrational modes in a molecule to investigate the molecular conformation. The coupling shows up as off-diagonal peaks in a 2D graph of the vibrational response of the molecule, analogous to the spin coupling observed in multidimensional NMR spectroscopy. Both spin coupling and vibrational coupling are sensitive probes of the molecular conformation, but 2D vibrational spectroscopy shows orders of magnitude better time resolution than NMR. In this Account, we use 2D vibrational spectroscopy to study molecular machines based on rotaxanes. These devices consist of a linear thread and a macrocycle that is noncovalently locked onto the thread. In the rotaxanes we study, the macrocycle and the thread both contain CO and NH groups. By determining the coupling between the stretching modes of these goups from the cross peaks in the 2D spectrum, we directly and quantitatively probe the relative position and orientation of the macrocycle and the thread for both a small

  14. Next-Generation Sequencing-Based Molecular Diagnosis of Choroideremia

    Directory of Open Access Journals (Sweden)

    Kayo Shimizu

    2015-07-01

    Full Text Available We screened patients with choroideremia using next-generation sequencing (NGS and identified a novel mutation and a known mutation in the CHM gene. One patient presented an atypical fundus appearance for choroideremia. Another patient presented macular hole retinal detachment in the left eye. The present case series shows the utility of NGS-based screening in patients with choroideremia. In addition, the presence of macular hole in 1 of the 2 patients, together with a previous report, indicated the susceptibility of patients with choroideremia to macular hole.

  15. Polarization conversion-based molecular sensing using anisotropic plasmonic metasurfaces

    Science.gov (United States)

    Verre, R.; Maccaferri, N.; Fleischer, K.; Svedendahl, M.; Odebo Länk, N.; Dmitriev, A.; Vavassori, P.; Shvets, I. V.; Käll, M.

    2016-05-01

    Anisotropic media induce changes in the polarization state of transmitted and reflected light. Here we combine this effect with the refractive index sensitivity typical of plasmonic nanoparticles to experimentally demonstrate self-referenced single wavelength refractometric sensing based on polarization conversion. We fabricated anisotropic plasmonic metasurfaces composed of gold dimers and, as a proof of principle, measured the changes in the rotation of light polarization induced by biomolecular adsorption with a surface sensitivity of 0.2 ng cm-2. We demonstrate the possibility of miniaturized sensing and we show that experimental results can be reproduced by analytical theory. Various ways to increase the sensitivity and applicability of the sensing scheme are discussed.Anisotropic media induce changes in the polarization state of transmitted and reflected light. Here we combine this effect with the refractive index sensitivity typical of plasmonic nanoparticles to experimentally demonstrate self-referenced single wavelength refractometric sensing based on polarization conversion. We fabricated anisotropic plasmonic metasurfaces composed of gold dimers and, as a proof of principle, measured the changes in the rotation of light polarization induced by biomolecular adsorption with a surface sensitivity of 0.2 ng cm-2. We demonstrate the possibility of miniaturized sensing and we show that experimental results can be reproduced by analytical theory. Various ways to increase the sensitivity and applicability of the sensing scheme are discussed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01336h

  16. Manganese-Based Molecular Electrocatalysts for Oxidation of Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hulley, Elliott; Kumar, Neeraj; Raugei, Simone; Bullock, R. Morris

    2015-10-05

    Oxidation of H2 (1 atm) is catalyzed by the manganese electrocatalysts [(P2N2)MnI(CO)(bppm)]+ and [(PNP)MnI(CO)(bppm)]+ (P2N2= 1,5-dibenzyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane; PNP = (Ph2PCH2)2NMe); bppm = (PArF2)2CH2, and ArF = 3,5-(CF3)2C6H3). In fluorobenzene solvent using 2,6-lutidine as the exogeneous base, the turnover frequency for [(P2N2)MnI(CO)(bppm)]+ is 3.5 s-1 with an estimated overpotential of 590 mV. For [(PNP)MnI(CO)(bppm)], in fluorobenzene solvent using N-methylpyrrolidine as the exogeneous base, the turnover frequency is 1.4 s-1 with an estimated overpotential of 700 mV. Density functional theory calculations suggest that the slow step in the catalytic cycle is proton transfer from the oxidized 17-electron manganese hydride, e.g., [(P2N2)MnIIH(CO)(bppm)]+ to the pendant amine. The computed activation barrier for intramolecular proton transfer from the metal to the pendant amine is 20.4 kcal/mol in [(P2N2)MnIIH(CO)(bppm)]+ and 21.3 kcal/mol in [(PNP)MnI(CO)(bppm)]. The high barrier appears to result from both the unfavorability of metal-to-nitrogen proton transfer (thermodynamically uphill by 6.6 pKa units, 9 kcal/mol), as well as the relatively long manganese-nitrogen separation in the MnIIH complexes.

  17. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    International Nuclear Information System (INIS)

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here

  18. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Ting-Chou [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Korczyńska, Justyna [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom); Smith, David K. [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Brzozowski, Andrzej Marek, E-mail: marek@ysbl.york.ac.uk [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom)

    2008-09-01

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here.

  19. Molecular evidence of Burkholderia pseudomallei genotypes based on geographical distribution.

    Science.gov (United States)

    Zulkefli, Noorfatin Jihan; Mariappan, Vanitha; Vellasamy, Kumutha Malar; Chong, Chun Wie; Thong, Kwai Lin; Ponnampalavanar, Sasheela; Vadivelu, Jamuna; Teh, Cindy Shuan Ju

    2016-01-01

    Background. Central intermediary metabolism (CIM) in bacteria is defined as a set of metabolic biochemical reactions within a cell, which is essential for the cell to survive in response to environmental perturbations. The genes associated with CIM are commonly found in both pathogenic and non-pathogenic strains. As these genes are involved in vital metabolic processes of bacteria, we explored the efficiency of the genes in genotypic characterization of Burkholderia pseudomallei isolates, compared with the established pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) schemes. Methods. Nine previously sequenced B. pseudomallei isolates from Malaysia were characterized by PFGE, MLST and CIM genes. The isolates were later compared to the other 39 B. pseudomallei strains, retrieved from GenBank using both MLST and sequence analysis of CIM genes. UniFrac and hierachical clustering analyses were performed using the results generated by both MLST and sequence analysis of CIM genes. Results. Genetic relatedness of nine Malaysian B. pseudomallei isolates and the other 39 strains was investigated. The nine Malaysian isolates were subtyped into six PFGE profiles, four MLST profiles and five sequence types based on CIM genes alignment. All methods demonstrated the clonality of OB and CB as well as CMS and THE. However, PFGE showed less than 70% similarity between a pair of morphology variants, OS and OB. In contrast, OS was identical to the soil isolate, MARAN. To have a better understanding of the genetic diversity of B. pseudomallei worldwide, we further aligned the sequences of genes used in MLST and genes associated with CIM for the nine Malaysian isolates and 39 B. pseudomallei strains from NCBI database. Overall, based on the CIM genes, the strains were subtyped into 33 profiles where majority of the strains from Asian countries were clustered together. On the other hand, MLST resolved the isolates into 31 profiles which formed three clusters

  20. Highly selective molecular recognition and high throughput detection of melamine based on molecularly imprinted sol-gel film

    Energy Technology Data Exchange (ETDEWEB)

    Yu Jinghua, E-mail: cclj4ever@126.com [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Zhang Congcong; Dai Ping; Ge Shenguang [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2009-10-05

    Multimode reader has been generally applied in immunoassay, and in the proposed paper, the 96 well micro-plate was modified with molecularly imprinted melamine sol-gel film, based on which the highly selective and high throughput detection of melamine was achieved. Melamine was imprinted into silica sol-gel films directly using phenyltrimethoxysilane and methyltrimethoxysilane as functionalized organosilicon precursors. The binding characteristic of the imprinted film to melamine was evaluated by equilibrium binding experiments and the morphology was studied by scanning electronic microscope (SEM). Scatchard analysis was carried out to estimate the binding parameters of the imprinted film. The proposed method exhibited excellent selectivity because of specific recognition of MM by molecularly imprinted film. Under the optimum conditions, the chemiluminescence (CL) intensity had a linear relationship against the concentration of melamine over the range of 0.1-50 {mu}g mL{sup -1} with a lower detection limit of 0.02 {mu}g mL{sup -1}.

  1. Una experiencia en la selección de pilotos aéreos

    Directory of Open Access Journals (Sweden)

    P. BARDERA MORA

    2004-01-01

    Full Text Available El presente artículo recoge una experiencia concreta en la selección de pilotos de aeronaves, la que se lleva a cabo en el Centro de Psicología de La Flota (Base Naval de Rota. Se ha plasmado una experiencia real en la selección de personal, tal y como se lleva a cabo, en virtud de las propias necesidades. Desde que los aspirantes encuentran en la aeronáutica su vocación hasta que llegan a pilotar un avión deberán pasar muchos controles, uno de los primeros, será superar una valoración psicológica, que conlleva, tanto la evaluación aptitudinal, como la de personalidad. La ¿seguridad¿ es nuestro constante objetivo. Uno de los instrumentos que más frutos ha dado en la predicción de errores e incidentes, ha sido el polirreactímetro; pero sin duda el criterio diferencial viene marcado por los rasgos de personalidad. Pilotar aviones es uno de esos puestos de trabajo que entraña riesgo por si mismo, además se manejan máquinas de gran valor económico; las pérdidas que puede acarrear una selección de personal ineficaz son muy elevadas.

  2. Detecting Molecular Properties by Various Laser-Based Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, Tse-Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effective energy transfer and the corresponding energy transfer time is ~6 ps. In addition, results from hole burning spectroscopy indicated that the chlorophyll dimer of the C714 state has a large distribution of the dimer geometry. Direct observation of vibrational peaks and evolution of coumarin 153 in the electronic excited state was demonstrated by using the fs/ps CARS, a variation of time-resolved coherent anti-Stokes Raman spectroscopy. In three different solvents, methanol, acetonitrile, and butanol, a vibration peak related to the stretch of the carbonyl group exhibits different relaxation dynamics. Laser-induced fluorescence microscopy, along with the biomimetic containers-liposomes, allows the measurement of the enzymatic activity of individual alkaline phosphatase from bovine intestinal mucosa without potential interferences from glass surfaces. The result showed a wide distribution of the enzyme reactivity. Protein structural variation is one of the major reasons that are responsible for this highly heterogeneous behavior.

  3. Molecular Phylogenetic: Organism Taxonomy Method Based on Evolution History

    Directory of Open Access Journals (Sweden)

    N.L.P Indi Dharmayanti

    2011-03-01

    Full Text Available Phylogenetic is described as taxonomy classification of an organism based on its evolution history namely its phylogeny and as a part of systematic science that has objective to determine phylogeny of organism according to its characteristic. Phylogenetic analysis from amino acid and protein usually became important area in sequence analysis. Phylogenetic analysis can be used to follow the rapid change of a species such as virus. The phylogenetic evolution tree is a two dimensional of a species graphic that shows relationship among organisms or particularly among their gene sequences. The sequence separation are referred as taxa (singular taxon that is defined as phylogenetically distinct units on the tree. The tree consists of outer branches or leaves that represents taxa and nodes and branch represent correlation among taxa. When the nucleotide sequence from two different organism are similar, they were inferred to be descended from common ancestor. There were three methods which were used in phylogenetic, namely (1 Maximum parsimony, (2 Distance, and (3 Maximum likehoood. Those methods generally are applied to construct the evolutionary tree or the best tree for determine sequence variation in group. Every method is usually used for different analysis and data.

  4. Recent advances in molecular electronics based on carbon nanotubes.

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

    2010-01-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field. PMID:21137718

  5. Molecular MRI based on hyper-polarized xenon

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging (MRI) has a high importance in medicine as it enables the observation of the organs inside the body without the use of radiative or invasive techniques. However it is known to suffer from poor sensitivity. To circumvent this limitation, a key solution resides in the use of hyper-polarized species. Among the entities with which we can drastically increase nuclear polarization, xenon has very specific properties through its interactions with its close environment that lead to a wide chemical shift bandwidth. The goal is thus to use it as a tracer. This PhD thesis focuses on the concept of 129Xe MRI-based sensors for the detection of biological events. In this approach, hyper-polarized xenon is vectorized to biological targets via functionalized host systems, and then localized thanks to fast dedicated MRI sequences. The conception and set-up of a spin-exchange optical pumping device is first described. Then studies about the interaction of the hyper-polarized noble gas with new cryptophanes susceptible to constitute powerful host molecules are detailed. Also the implementation of recent MRI sequences optimized for the transient character of the hyper-polarization and taking profit of the xenon in-out exchange is described. Applications of this approach for the detection of metallic ions and cellular receptors are studied. Finally, our first in vivo results on a small animal model are presented. (author)

  6. ¿Innovando en la gestión pública? La experiencia mexicana en los gobiernos locales

    Directory of Open Access Journals (Sweden)

    José Juan Sánchez González

    2010-01-01

    Full Text Available El ensayo tiene como propósito describir la experiencia mexicana de los gobiernos locales, para determinar si han innovado o imitado en la gestión pública. La manera de abordarlo es bajo el siguiente esquema: primero, como una aproximación para comprender la innovación, se define y se clasifica con base en las tipologías más comunes. Segundo, para diferenciar la forma de innovación en la gestión pública, se recurre a Drucker (1985 y 2005, quien aporta ideas para innovar en los negocios. Tercero, se revisa la forma de innovar en la gestión pública con los argumentos de Metcalfe (1999. Cuarto, es descrita la experiencia de la Nueva Gestión Pública (NGP en catorce gobiernos estatales en México a partir de sus estrategias de innovación. Quinto, son analizadas las innovaciones en gobiernos locales mexicanos bajo la experiencia del Premio Gobierno y Gestión Local, para contrastar los resultados alcanzados; y por último, se concluye que es necesario pasar de la "imitación" a la "innovación" en los gobiernos locales.

  7. Electronic shift register memory based on molecular electron-transfer reactions

    International Nuclear Information System (INIS)

    The design of a shift register memory at the molecular level is described in detail. The memory elements are based on a chain of electron-transfer molecules incorporated on a very large scale integrated (VLSI) substrate, and the information is shifted by photoinduced electron-transfer reactions. The design requirements for such a system are discussed, and several realistic strategies for synthesizing these systems are presented. The immediate advantage of such a hybrid molecular/VLSI device would arise from the possible information storage density. The prospect of considerable savings of energy per bit processed also exists. This molecular shift register memory element design solves the conceptual problems associated with integrating molecular size components with larger (micron) size features on a chip

  8. Antes de los Estudios Culturales. Robert Warshow y la experiencia

    Directory of Open Access Journals (Sweden)

    Antonio Lastra

    2008-01-01

    Full Text Available Este artículo estudia la influencia del concepto de experiencia que desarrolla Robert Warshow. Warshow ha supuesto el contrapunto americano a las teorías desarrolladas por Walter Benjamien en Europa. Si bien ambos insistieron en la pobreza de la experiencia, como resultado de la tecnificación de la sociedad, Warshow supo introducir matizaciones que influyeron en todo el círculo de intelectuales concentrados en Nueva York durante la etapa de consolidación de los Estudios Culturales. This paper studies the influence of the experience concept by Robert Warshow. Warshow is the American counterpoint to theories developed by Walter Benjamin in Europe. Although both insisted in the poverty of experience, as a result of technique, Warshow knew how to introduce nuances that influenced intellectuals in New York as Cultural Studies emerged.

  9. Biomedical wellness monitoring system based upon molecular markers

    Science.gov (United States)

    Ingram, Whitney

    2012-06-01

    We wish to assist caretakers with a sensor monitoring systems for tracking the physiological changes of homealone patients. One goal is seeking biomarkers and modern imaging sensors like stochastic optical reconstruction microscopy (STORM), which has achieved visible imaging at the nano-scale range. Imaging techniques like STORM can be combined with a fluorescent functional marker in a system to capture the early transformation signs from wellness to illness. By exploiting both microscopic knowledge of genetic pre-disposition and the macroscopic influence of epigenetic factors we hope to target these changes remotely. We adopt dual spectral infrared imaging for blind source separation (BSS) to detect angiogenesis changes and use laser speckle imaging for hypertension blood flow monitoring. Our design hypothesis for the monitoring system is guided by the user-friendly, veteran-preferred "4-Non" principles (noninvasive, non-contact, non-tethered, non-stop-to-measure) and by the NIH's "4Ps" initiatives (predictive, personalized, preemptive, and participatory). We augment the potential storage system with the recent know-how of video Compressive Sampling (CSp) from surveillance cameras. In CSp only major changes are saved, which reduces the manpower cost of caretakers and medical analysts. This CSp algorithm is based on smart associative memory (AM) matrix storage: change features and detailed scenes are written by the outer-product and read by the inner product without the usual Harsh index for image searching. From this approach, we attempt to design an effective household monitoring approach to save healthcare costs and maintain the quality of life of seniors.

  10. Objetividad y medida de la experiencia subjetiva consciente

    OpenAIRE

    Moscoso, Javier

    2001-01-01

    Este artículo examina las posibilidades de desarrollar una ciencia objetiva de la experiencia subjetiva en los estudios de fisiología y psicología experimental de mediados del siglo XIX. Se discute la historicidad de las categorías epistémicas y se aboga por una noción de objetividad sostenida sobre la noción de comunidad epistémica.

  11. Museos construidos y reconstruidos. Experiencias educativas para la creatividad

    Directory of Open Access Journals (Sweden)

    Romina Elisondo

    2015-09-01

    Full Text Available Los museos son espacios educativos promisorios para el aprendizaje y la creatividad. En el artículo contamos experiencias vinculadas a la construcción de propuestas educativas en museos, entendidos como construcciones sociales. Específicamente, nos referimos a dos propuestas educativas: un museo construido en el aula y una visita a un museo fuera del aula. Nos interesa describir las propuestas desarrolladas haciendo especial hincapié en las percepciones y valoraciones de los estudiantes respecto de las potencialidades educativas de los museos. Participaron de las experiencias estudiantes de las carreras de Licenciatura en Psicopedagogía y Educación Especial de la Universidad Nacional de Río Cuarto. Los museos, construidos y visitados, generan espacios para aprender y vivenciar experiencias significativas de aprendizaje. También se observan impactos positivos de los museos en la promoción de la creatividad y el desarrollo de innovaciones educativas. Historias personales, grupales y sociales circulan por los museos configurando entornos propicios para construir conocimientos dentro y fuera de las aulas.

  12. Qué sujeto para qué experiencia?

    Directory of Open Access Journals (Sweden)

    Yves SCHWARTZ

    2011-04-01

    Full Text Available En el espacio de un dialogo aquí iniciado con la corriente de didáctica profesional este texto se propone restituir una dinámica intelectual que va del concepto de experiencia al concepto de actividad. Este último concepto parece necesitar lo que se considera como un drama en la experiencia humana (el debate de las normas y mostrar cómo la experiencia como sedimentación inestable de actividades es una matriz permanente de la historia. ¿Cuál puede ser entonces el precepto de los saberes generados por un ser así definido como ser de actividad? Se formulan verdaderos problemas epistemológicos en las relaciones entre las diversas formas del saber y las diversas formas de expresión en el lenguaje, como también para el precepto de los diversos saberes en su relación con la historicidad. Un problema no solo epistemológico sino también político pues podemos apreciar una cartografía de del precepto propio de las relaciones de saberes / poderes y aquellos a la deriva de la gobernanza del trabajo humano. Finalizamos tratando una problemática del , que pueda ser coherente con los patrimonios aquí reivindicados en la construcción del concepto ergológico de actividad.

  13. Albert Camus: su experiencia y su teoria de la tragedia

    Directory of Open Access Journals (Sweden)

    Inés de Cassagne

    2013-05-01

    Full Text Available Camus encuentra en el género trágico un cauce adecuado para su experiencia. Esta experiencia, cuya savia alimenta todos sus frutos literarios, es la del doble rostro de la existencia humana en este mundo. A ella responde como artista, y como hombre, en el perfecto equilibrio del “rechazo” y el “consentimiento”. Cuando decide en 1956 publicar su primer testimonio juvenil, El revés y el derecho, al prologarlo, confirma aquel testimonio y expone su decisión artística. Cambiar la vida, sin cambiar el mundo. Cambiar la miseria, sin cambiar el sol, la belleza, mediante la fórmula de equilibrio de “rechazo” y “consentimiento”.Esta fórmula no podría cuajar de modo acabado sino en el cauce de la tragedia, herencia de los griegos. Para quien revive la experiencia del destino humano en un mundo sin más allá, la sola trascendencia posible de perfectibilidad sólo puede darse en el espacio ideal del arte, único capaz de acoger dramáticamente la tensión entre los polos contrastantes la vida que colma y a la vez decepciona y pasa.

  14. ¿Metrópolis ingobernables? Experiencias europeas ¿Metrópolis ingobernables? Experiencias europeas

    Directory of Open Access Journals (Sweden)

    Christian Lefèvre

    2010-12-01

    Full Text Available Las áreas metropolitanas se han convertido en lugares en los que tienen lugar algunos de los mayores desafíos para el gobierno de nuestras sociedades (desigualdades sociales y territoriales, desarrollo económico, la diversidad étnica y cultural, la preservación del medio ambiente, etc.. Sin embargo, a pesar de su relevancia como espacios para el tratamiento de estos problemas, las áreas metropolitanas tienen grandes dificultades para transformarse en territorios políticos, es decir, para alcanzar un nivel de agente político suficiente (como actor colectivo para producir políticas adecuadas que aborden estos problemas y produzcan estrategias colectivas que orienten su desarrollo futuro. Para tratar este tema, este artículo se centrará en primer lugar en los principales obstáculos que les impiden alcanzar el nivel de actor político, que son comunes a la mayoría de los países europeos: la resistencia del Estado a otorgar a estos territorios las funciones y recursos adecuados en el proceso de descentralización y su preferencia por el reforzamiento de los niveles de gobierno existentes; la oposición de estos niveles de gobierno y la falta de apoyo de la sociedad civil (actores económicos y población. En un segundo apartado, este artículo presentará diferentes experiencias que han tenido lugar en la última década para superar estos obstáculos. Centrándose en la pacificación de las relaciones de poder a nivel metropolitano mediante conferencias, cartas y pactos metropolitanos y “políticas procedimentales” como la planificación estratégica, el autor considera que estas experiencias no parecen ofrecer potencialidades para la reducción del conflicto político entre actores y concluye con un tono pesimista sobre la gobernabilidad de las áreas metropolitanas.Metropolitan areas have become places where some of the major issues and stakes for the government of our societies are taking place (social and territorial

  15. Giant tunnel magneto-resistance in graphene based molecular tunneling junction

    Science.gov (United States)

    Wang, Bin; Li, Jianwei; Yu, Yunjin; Wei, Yadong; Wang, Jian; Guo, Hong

    2016-02-01

    We propose and theoretically investigate a class of stable zigzag graphene nanoribbon (ZGNR) based molecular magnetic tunneling junctions (MTJs). For those junctions having pentagon-connecting formations, huge tunnel magneto-resistance (TMR) is found. Different from most of the other proposed molecular junctions, the huge TMR in our structures is generic, and is not significantly affected by external parameters such as bias voltage, gate voltage, length of the molecule and width of the ZGNRs. The double pentagon-connecting formation between the molecule and ZGNRs is critical for the remarkable TMR ratio, which is as large as ~2 × 105. These molecular MTJs behave as almost perfect spin filters and spin valve devices. Other connecting formations of the ZGNR based MTJs lead to much smaller TMR. By first principles analysis, we reveal the microscopic physics responsible for this phenomenon.

  16. Fabrication of tunnel junction-based molecular electronics and spintronics devices

    International Nuclear Information System (INIS)

    Tunnel junction-based molecular devices (TJMDs) are highly promising for realizing futuristic electronics and spintronics devices for advanced logic and memory operations. Under this approach, ∼2.5 nm molecular device elements bridge across the ∼2-nm thick insulator of a tunnel junction along the exposed side edge(s). This paper details the efforts and insights for producing a variety of TJMDs by resolving multiple device fabrication and characterization issues. This study specifically discusses (i) compatibility between tunnel junction test bed and molecular solutions, (ii) optimization of the exposed side edge profile and insulator thickness for enhancing the probability of molecular bridging, (iii) effect of fabrication process-induced mechanical stresses, and (iv) minimizing electrical bias-induced instability after the device fabrication. This research will benefit other researchers interested in producing TJMDs efficiently. TJMD approach offers an open platform to test virtually any combination of magnetic and nonmagnetic electrodes, and promising molecules such as single molecular magnets, porphyrin, DNA, and molecular complexes.

  17. Double-hairpin molecular-beacon-based amplification detection for gene diagnosis linked to cancer.

    Science.gov (United States)

    Xu, Huo; Zhang, Rongbo; Li, Feng; Zhou, Yingying; Peng, Ting; Wang, Xuedong; Shen, Zhifa

    2016-09-01

    A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related KRAS gene detection based on the one-to-two stoichiometry. During target DNA detection, DHMB can execute signal transduction even if no any exogenous element is involved. Unlike the conventional molecular beacon based on the one-to-one interaction, one target DNA not only hybridizes with one DHMB and opens its hairpin but also promotes the interaction between two DHMBs, causing the separation of two fluorophores from quenchers. This leads to an enhanced fluorescence signal. As a result, the target KRAS gene is able to be detected within a wide dynamic range from 0.05 to 200 nM with the detection limit of 50 pM, indicating a dramatic improvement compared with traditional molecular beacons. Moreover, the point mutations existing in target DNAs can be easily screened. The potential application for target species in real samples was indicated by the analysis of PCR amplicons of DNAs from the DNA extracted from SW620 cell. Besides becoming a promising candidate probe for molecular biology research and clinical diagnosis of genetic diseases, the DHMB is expected to provide a significant insight into the design of DNA probe-based homogenous sensing systems. Graphical Abstract A powerful double-hairpin molecular beacon (DHMB) was developed for cancer-related gene KRAS detection based on the one-to-two stoichiometry. Without the help of any exogenous probe, the point mutation is easily screened, and the target DNA can be quantified down to 50 pM, indicating a dramatic improvement compared with traditional molecular beacons. PMID:27422649

  18. Well-Defined Polyethylene-Based Random, Block, and Bilayered Molecular Cobrushes

    KAUST Repository

    Zhang, Hefeng

    2015-06-09

    Novel well-defined polyethylene-based random, block, and bilayered molecular cobrushes were synthesized through the macromonomer strategy. Two steps were involved in this approach: (i) synthesis of norbornyl-terminated macromonomers of polyethylene (PE), polycaprolactone (PCL), poly(ethylene oxide) (PEO), and polystyrene (PS), as well as polyethylene-b-polycaprolactone (PE-b-PCL), by esterification of the hydroxyl-terminated precursors (PE, PCL, PEO, PS, and PE-b-PCL) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis (co)polymerization of the resulting macromonomers to afford the PE-based molecular cobrushes. The PE-macromonomers were synthesized by polyhomologation of dimethylsulfoxonium methylide, while the others by anionic polymerization. Proton nuclear magnetic resonance spectroscopy (1H NMR) and high-temperature gel permeation chromatography (HT-GPC) were used to imprint the molecular characteristics of all macromonomers and molecular brushes and differential scanning calorimetry (DSC) for the thermal properties. The bilayered molecular cobrushes of P(PE-b-PCL) adopt a wormlike morphology on silica wafer as visualized by atomic force microscopy (AFM). © 2015 American Chemical Society.

  19. Designing and Implementing a Hands-On, Inquiry-Based Molecular Biology Course

    Science.gov (United States)

    Regassa, Laura B.; Morrison-Shetlar, Alison I.

    2007-01-01

    Inquiry-based learning was used to enhance an undergraduate molecular biology course at Georgia Southern University, a primarily undergraduate institution in rural southeast Georgia. The goal was to use a long-term, in-class project to accelerate higher-order thinking, thereby enabling students to problem solve and apply their knowledge to novel…

  20. Synthesis and Characterization of Helicene-Based Imidazolium Salt and Its Application for Organic Molecular Electronics.

    Czech Academy of Sciences Publication Activity Database

    Storch, Jan; Sýkora, Jan; Žádný, Jaroslav; Strašák, Tomáš; Církva, Vladimír; Krbal, M.; Vacek, J.

    - : -, 2014. ISBN N. [From Carbon-Rich Molecules to Carbon-Based Materials. Casablanca (MA), 22.09.2014-25.09.2015] R&D Projects: GA TA ČR TA01010646 Institutional support: RVO:67985858 Keywords : helicenes * imidazolium cation * organic molecular semiconductor Subject RIV: CC - Organic Chemistry

  1. Towards a logic-based method to infer provenance-aware molecular networks

    OpenAIRE

    Aslaoui-Errafi, Zahira; Cohen-Boulakia, Sarah; Froidevaux, Christine; Gloaguen, Pauline; Poupon, Anne; Rougny, Adrien; Yahiaoui, Meriem

    2012-01-01

    International audience Providing techniques to automatically infer molecular networks is particularly important to understand complex relationships between biological objects. We present a logic-based method to infer such networks and show how it allows inferring signalling networks from the design of a knowledge base. Provenance of inferred data has been carefully collected, allowing quality evaluation. More precisely, our method (i) takes into account various kinds of biological experime...

  2. Anthraquinone-based demultiplexer and other multiple operations at the molecular level

    Indian Academy of Sciences (India)

    Navneet Kaur; Subodh Kumar

    2014-01-01

    Anthraquinone-based chemosensor L with pyridine units as additional functional groups has been found to show pH-dependent multiple coordinationmodes towards differentmetal ions (Co2+, Ni2+ and Cu2+). Based on these different absorption changes, this differential colorimetric chemosensor L has found promising applications as a multiple-mode molecular logic system, i.e., OR, three - input NOR, three - input INHIBIT, TRANSFER and 1:2 DEMUX.

  3. PyRosetta: a script-based interface for implementing molecular modeling algorithms using Rosetta

    OpenAIRE

    Chaudhury, Sidhartha; Lyskov, Sergey; Gray, Jeffrey J.

    2010-01-01

    Summary: PyRosetta is a stand-alone Python-based implementation of the Rosetta molecular modeling package that allows users to write custom structure prediction and design algorithms using the major Rosetta sampling and scoring functions. PyRosetta contains Python bindings to libraries that define Rosetta functions including those for accessing and manipulating protein structure, calculating energies and running Monte Carlo-based simulations. PyRosetta can be used in two ways: (i) interactive...

  4. Isatin based thiosemicarbazone derivatives as potential bioactive agents: Anti-oxidant and molecular docking studies

    Science.gov (United States)

    Haribabu, J.; Subhashree, G. R.; Saranya, S.; Gomathi, K.; Karvembu, R.; Gayathri, D.

    2016-04-01

    A new series of isatin based thiosemicarbazones has been synthesized from benzylisatin and unsubstituted/substituted thiosemicarbazides (1-5). The synthesized compounds were characterized by elemental analyses, and UV-Visible, FT-IR, 1H &13C NMR and mass spectroscopic techniques. Three dimensional molecular structure of three compounds (1, 3 and 4) was determined by single crystal X-ray crystallography. Anti-oxidant activity of the thiosemicarbazone derivatives showed their excellent scavenging effect against free radicals. In addition, all the compounds showed good anti-haemolytic activity. In silico molecular docking studies were performed to screen the anti-inflammatory and anti-tuberculosis properties of thiosemicarbazone derivatives.

  5. Benchmarking ab initio binding energies of hydrogen-bonded molecular clusters based on FTIR spectroscopy

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Du, Lin; Reiman, Heidi;

    2014-01-01

    Gibbs free binding energies in molecular complexes and clusters based on gas phase FTIR spectroscopy. The acetonitrile-HCl molecular complex is identified via its redshifted H-Cl stretching vibrational mode. We determine the Gibbs free binding energy, ΔG°295 K, to between 4.8 and 7.9 kJ mol(-1) and......Models of formation and growth of atmospheric aerosols are highly dependent on accurate cluster binding energies. These are most often calculated by ab initio electronic structure methods but remain associated with significant uncertainties. We present a computational benchmarking study of the...

  6. Optical materials based on molecular nano/microcrystals and ultrathin films

    Indian Academy of Sciences (India)

    A Patra; K Rajesh; T P Radhakrishnan

    2008-06-01

    Methodologies that we developed recently for the fabrication of molecular crystals with size variation in the nano to micro regime and polyelectrolyte templated mono and multilayer Langmuir–Blodgett films, are reviewed. The electronic absorption and strong fluorescence in the molecular nano/microcrystals are found to be size-dependent. Crystal structure and computational investigations provide a unified model to explain these observations. Role of polyelectrolyte templating in achieving stable and enhanced optical second harmonic generation response from LB films based on a hemicyanine amphiphile is highlighted.

  7. Toward molecular trait-based ecology through integration of biogeochemical, geographical and metagenomic data

    DEFF Research Database (Denmark)

    Raes, Jeroen; Letunic, Ivica; Yamada, Takuji;

    2011-01-01

    Using metagenomic 'parts lists' to infer global patterns on microbial ecology remains a significant challenge. To deduce important ecological indicators such as environmental adaptation, molecular trait dispersal, diversity variation and primary production from the gene pool of an ecosystem, we...... integrated 25 ocean metagenomes with geographical, meteorological and geophysicochemical data. We find that climatic factors (temperature, sunlight) are the major determinants of the biomolecular repertoire of each sample and the main limiting factor on functional trait dispersal (absence of biogeographic...... composition derived from metagenomes is an important quantitative readout for molecular trait-based biogeography and ecology....

  8. A density functional theory-based chemical potential equalisation approach to molecular polarizability

    Indian Academy of Sciences (India)

    Amita Wadehra; Swapan K Ghosh

    2005-09-01

    The electron density changes in molecular systems in the presence of external electric fields are modeled for simplicity in terms of the induced charges and dipole moments at the individual atomic sites. A chemical potential equalisation scheme is proposed for the calculation of these quantities and hence the dipole polarizability within the framework of density functional theory based linear response theory. The resulting polarizability is expressed in terms of the contributions from individual atoms in the molecule. A few illustrative numerical calculations are shown to predict the molecular polarizabilities in good agreement with available results. The usefulness of the approach to the calculation of intermolecular interaction needed for computer simulation is highlighted.

  9. Nonadiabatic molecular dynamics simulation: An approach based on quantum measurement picture

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2014-07-01

    Full Text Available Mixed-quantum-classical molecular dynamics simulation implies an effective quantum measurement on the electronic states by the classical motion of atoms. Based on this insight, we propose a quantum trajectory mean-field approach for nonadiabatic molecular dynamics simulations. The new protocol provides a natural interface between the separate quantum and classical treatments, without invoking artificial surface hopping algorithm. Moreover, it also bridges two widely adopted nonadiabatic dynamics methods, the Ehrenfest mean-field theory and the trajectory surface-hopping method. Excellent agreement with the exact results is illustrated with representative model systems, including the challenging ones for traditional methods.

  10. Ab initio based force field and molecular dynamics simulations of crystalline TATB.

    Science.gov (United States)

    Gee, Richard H; Roszak, Szczepan; Balasubramanian, Krishnan; Fried, Laurence E

    2004-04-15

    An all-atom force field for 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is presented. The classical intermolecular interaction potential for TATB is based on single-point energies determined from high-level ab initio calculations of TATB dimers. The newly developed potential function is used to examine bulk crystalline TATB via molecular dynamics simulations. The isobaric thermal expansion and isothermal compression under hydrostatic pressures obtained from the molecular dynamics simulations are in good agreement with experiment. The calculated volume-temperature expansion is almost one dimensional along the c crystallographic axis, whereas under compression, all three unit cell axes participate, albeit unequally. PMID:15267608

  11. Triazolyl-Based Molecular Gels as Ligands for Autocatalytic 'Click' Reactions.

    Science.gov (United States)

    Araújo, Marco; Díaz-Oltra, Santiago; Escuder, Beatriu

    2016-06-13

    The catalytic performance of triazolyl-based molecular gels was investigated in the Huisgen 1,3-dipolar cycloaddition of alkynes and azides. Low-molecular-weight gelators derived from l-valine were synthesized and functionalized with a triazole fragment. The resultant compounds formed gels either with or without copper, in a variety of solvents of different polarity. The gelators coordinated Cu(I) and exhibited a high catalytic activity in the gel phase for the model reaction between phenylacetylene and benzylazide. Additionally, the gels were able to participate in autocatalytic synthesis and the influence of small structural changes on their performance was observed. PMID:27168408

  12. Electrochemical sensor for dopamine based on a novel graphene-molecular imprinted polymers composite recognition element

    DEFF Research Database (Denmark)

    Mao, Yan; Bao, Yu; Gan, Shiyu;

    2011-01-01

    A novel composite of graphene sheets/Congo red-molecular imprinted polymers (GSCR-MIPs) was synthesized through free radical polymerization (FRP) and applied as a molecular recognition element to construct dopamine (DA) electrochemical sensor. The template molecules (DA) were firstly absorbed at...... sensor for highly sensitive and selective detection of DA was successfully constructed as demonstration based on the synthesized GSCR-MIPs nanocomposites. Under experimental conditions, selective detection of DA in a linear concentration range of 1.0×10−7–8.3×10−4M was obtained, which revealed a lower...

  13. A systematic revision on Caralluma species of Saudi Arabia based on karyological and molecular data

    International Nuclear Information System (INIS)

    A systematic revision of 13 species of the genus Caralluma (Apocynaceae - Asclepiadoideae - Ceropegieae) from the flora of Saudi Arabia based on the evaluation of karyological and molecular data was carried out. Karyotype criteria and polyploid variations were discussed. Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Random Amplified Polymorphic DNA (RAPD-PCR) techniques were also used in this study to distinguish these species. Karyotype features of the studied species and molecular data were used to reassess the relationships of the 13 species of Caralluma in the light of the current systems of classification. (author)

  14. Gold-based hybrid nanomaterials for biosensing and molecular diagnostic applications.

    Science.gov (United States)

    Kim, Jung Eun; Choi, Ji Hye; Colas, Marion; Kim, Dong Ha; Lee, Hyukjin

    2016-06-15

    The properties of gold nanomaterials are particularly of interest to many researchers, since they show unique physiochemical properties such as optical adsorption of specific wavelength of light, high electrical conductance with rich surface electrons, and facile surface modification with sulfhydryl groups. These properties have facilitated the use of gold nanomaterials in the development of various hybrid systems for biosensors and molecular diagnostics. Combined with various synthetic materials such as fluorescence dyes, polymers, oligonucleotides, graphene oxides (GO), and quantum dots (QDs), the gold-based hybrid nanomaterials offer multi-functionalities in molecular detection with high specificity and sensitivity. These two aspects result in the increase of detection speed as well as the lower detection limits, having shown that this diagnosis method is more effective than other conventional ones. In this review, we have highlighted various examples of nanomaterials for biosensing and molecular diagnostics. The gold-based hybrid systems are categorized by three distinct detection approaches, in which include (1) optical, such as surface plasmon resonance (SPR), RAMAN, and surface-enhanced Raman scattering (SERS), (2) fluorescence, such as förster resonance energy transfer (FRET) and nanomaterial surface energy transfer (NSET), and (3) electrochemical, such as potentiometic, amperometric, and conductometric. Each example provides the detailed mechanism of molecular detection as well as the supporting experimental result with the limit of detection (LOD). Lastly, future perspective on novel development of gold-based hybrid nanomaterials is discussed as well as their challenges. PMID:26894985

  15. Correlation of microarray-based breast cancer molecular subtypes and clinical outcomes: implications for treatment optimization

    International Nuclear Information System (INIS)

    Optimizing treatment through microarray-based molecular subtyping is a promising method to address the problem of heterogeneity in breast cancer; however, current application is restricted to prediction of distant recurrence risk. This study investigated whether breast cancer molecular subtyping according to its global intrinsic biology could be used for treatment customization. Gene expression profiling was conducted on fresh frozen breast cancer tissue collected from 327 patients in conjunction with thoroughly documented clinical data. A method of molecular subtyping based on 783 probe-sets was established and validated. Statistical analysis was performed to correlate molecular subtypes with survival outcome and adjuvant chemotherapy regimens. Heterogeneity of molecular subtypes within groups sharing the same distant recurrence risk predicted by genes of the Oncotype and MammaPrint predictors was studied. We identified six molecular subtypes of breast cancer demonstrating distinctive molecular and clinical characteristics. These six subtypes showed similarities and significant differences from the Perou-Sørlie intrinsic types. Subtype I breast cancer was in concordance with chemosensitive basal-like intrinsic type. Adjuvant chemotherapy of lower intensity with CMF yielded survival outcome similar to those of CAF in this subtype. Subtype IV breast cancer was positive for ER with a full-range expression of HER2, responding poorly to CMF; however, this subtype showed excellent survival when treated with CAF. Reduced expression of a gene associated with methotrexate sensitivity in subtype IV was the likely reason for poor response to methotrexate. All subtype V breast cancer was positive for ER and had excellent long-term survival with hormonal therapy alone following surgery and/or radiation therapy. Adjuvant chemotherapy did not provide any survival benefit in early stages of subtype V patients. Subtype V was consistent with a unique subset of luminal A intrinsic

  16. Discovery of Anti-SARS Coronavirus Drug Based on Molecular Docking and Database Screening

    Institute of Scientific and Technical Information of China (English)

    CHEN,Hai-Feng(陈海峰); YAO,Jian-Hua(姚建华); SUN,Jing(孙晶); LI,Qiang(李强); LI,Feng(李丰); FAN,Bo-Tao(范波涛); YUAN,Shen-Gang(袁身刚)

    2004-01-01

    The active site of 3CL proteinase (3CLpro) for coronavirus was identified by comparing the crystal structures of human and porcine coronavirus. The inhibitor of the main protein of rhinovirus (Ag7088) could bind with 3CLpro of human coronavirus, then it was selected as the reference for molecular docking and database screening. The ligands from two databases were used to search potential lead structures with molecular docking. Several structures from natural products and ACD-SC databases were found to have lower binding free energy with 3CLpro than that of Ag7088. These structures have similar hydrophobicity to Ag7088. They have complementary electrostatic potential and hydrogen bond acceptor and donor with 3CLpro, showing that the strategy of anti-SARS drug design based on molecular docking and database screening is feasible.

  17. A Cucurbit[7]uril Based Molecular Shuttle Encoded by Visible Room-Temperature Phosphorescence.

    Science.gov (United States)

    Gong, Yifan; Chen, Hui; Ma, Xiang; Tian, He

    2016-06-17

    A visible room-temperature phosphorescence (RTP) signal, generated by complexation of cururbit[7]uril (CB[7]) and bromo-substituted isoquinoline in aqueous solution, is employed to address the shuttling of a pH-controlling molecular shuttle fabricated by CB[7] and a phosphor 6-bromoisoquinoline derivative IQC[5]. The CB[7] host shuttles along the axial guest under acidic conditions, accompanied by a weak RTP emission signal, while deprotonation of the guest IQC[5] makes the CB[7] wheel locate on the phosphor group, leading to intense RTP emission. The switching RTP emission of the molecular shuttle, via pH adjusting, can be visibly identified by the naked eye. This is the first CB-based molecular shuttle with an RTP signal as the output address of its shuttling and conformation. PMID:26548653

  18. STM investigation of imine-based molecular switches on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Johannes; Grill, Leonhard [Institut fuer Experimentalphysik, Freie Universitaet Berlin (Germany); Luo, Ying; Haag, Rainer [Institut fuer Chemie und Biochemie - Organische Chemie, Freie Universitaet Berlin (Germany)

    2009-07-01

    In the field of molecular electronics, molecular switches are highly relevant because they can control the conductance. Switches based on azobenzene molecules have attracted large interest in the last years. A very similar molecular switch can be created by replacing the functional azo group by an imine group, which does not considerably alter the electronic structure of the molecule and conserves the capability of undergoing a reversible trans-cis isomerisation. Such processes have already been studied in solution and the gas phase but not on surfaces. In this work, imine molecules with four tert-butyl groups were adsorbed on Au(111) and their adsorption and switching behaviour were studied using a low temperature STM. The molecules were found to form two types of ordered islands and an interesting irreversible switching behaviour was observed when looking at their temperature dependence, because the number of trans isomers was reduced upon heating of the sample.

  19. Talante y memoria: acerca de las experiencias extralingüísticas

    OpenAIRE

    Serrano Ribeiro, José Luis

    2015-01-01

    Proponemos como paradigma de toda experiencia extralingüística la transición del sueño a la vigilia. Con esto comprobaremos que sin lenguaje y sin memoria no dispondríamos de ninguna experiencia vital de la realidad, aunque nos sostenga el hilo míni

  20. La experiencia de Inglaterra y Gales en micromedición de agua potable

    OpenAIRE

    Ferro, Gustavo

    1999-01-01

    El trabajo explora la experiencia de reemplazo progresivo de un esquema tarifario basado en superficie edificada a uno de micromedición. La experiencia destaca por haber estado acompañada de estudios sociales que arrojan luz para futuras situaciones semejantes.

  1. Competency-Based Education for the Molecular Genetic Pathology Fellow: A Report of the Association for Molecular Pathology Training and Education Committee

    OpenAIRE

    Talbert, Michael L.; Dunn, S. Terence; Hunt, Jennifer; Hillyard, David R.; Mirza, Imran; Nowak, Jan A.; Van Deerlin, Vivianna; Vnencak-Jones, Cindy L.

    2009-01-01

    The following report represents guidelines for competency-based fellowship training in Molecular Genetic Pathology (MGP) developed by the Association for Molecular Pathology Training and Education Committee and Directors of MGP Programs in the United States. The goals of the effort were to describe each of the Accreditation Council for Graduate Medical Education competencies as they apply to MGP fellowship training, provide a summary of goals and objectives, and recommend assessment tools. Th...

  2. Reflexiones sobre la estrategia de rehabilitación basada en la comunidad (RBC: la experiencia de un programa de RBC en Bolivia Reflections on community-based rehabilitation strategy (CBR: the experience of a CBR program in Bolivia

    Directory of Open Access Journals (Sweden)

    Urko Díaz-Aristizabal

    2012-01-01

    Full Text Available La Rehabilitación Basada en la Comunidad (RBC es una estrategia de desarrollo comunitario avalada por la Organización Mundial de la Salud (OMS, la Organización Internacional del Trabajo (OIT y la Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura (UNESCO, que persigue la rehabilitación, la igualdad de oportunidades y la integración social de las Personas con Discapacidad (PD en sus entornos. Con este objetivo promueve la colaboración entre las PD, sus familias y los diferentes actores de la comunidad involucrados, así como el liderazgo comunitario y la participación de las PD mediante el impulso de la colaboración multisectorial. Este artículo expone los antecedentes históricos y las características fundamentales de la estrategia de RBC a partir de un programa llevado a cabo por una fundación del departamento de Cochabamba (Bolivia, para después incidir en algunos aspectos referentes al contexto sociocultural, que especialmente en situaciones de interculturalidad, pueden determinar que un programa de RBC tenga éxito o esté abocado al fracaso.Community-Based Rehabilitation (CBR is a strategy for community development endorsed by the World Health Organization (WHO, the International Labor Office (ILO and the United Nations Educational, Scientific and Cultural Organization (UNESCO. It is designed to promote rehabilitation, equal opportunity and social inclusion of Disabled Persons (DP in their home communities by fostering cooperation among disabled individuals, their families, and other concerned social actors, it encourages community leadership and full social participation by DP through multi-sector cooperation. This article explores the historical antecedents and basic features of CBR strategy through an analysis of a directed culture change initiative developed by a foundation in the Cochabamba administrative region of Bolivia. Especially in intercultural environments, certain aspects of the socio

  3. EXPERIENCIA DEL ENTRENAMIENTO MUSICAL EN UNA UNIVERSIDAD PARTICULAR DE LIMA

    OpenAIRE

    Daniel Ravelo Franco

    2012-01-01

    RESUMEN: El objetivo de la Revolución del Entrenamiento Musical es aprovechar las modernas herramientas tecnológicas para la educación, aplicándolas al entrenamiento auditivo, dentro de un programa de formación musical profesional. En este trabajo, se presentará la experiencia de transformación del curso presencial de Nivelación en Lectura y Entrenamiento Auditivo, de un pregrado universitario de Música, a la modalidad b-learning. La modalidad b-learning de este curso se estableció sobre un A...

  4. Cruzando la frontera: Experiencias desde los márgenes

    Directory of Open Access Journals (Sweden)

    Alejandra AQUINO MORESCHI

    2012-01-01

    Full Text Available Existen muchos estudios sobre las políticas estatales para el control de las fronteras entre norte y sur; sin embargo, hay muy pocos sobre las estrategias concretas, individuales y colectivas que siguen los migrantes para atravesarlas y sobre cómo experimentan este momento clave en su trayectoria migratoria. El artículo siguiente busca abonar a esta tarea; para ello presenta un análisis etnográfico del cruce de la frontera de jóvenes zapotecas y tojolabales originarios de comunidades rurales de Chiapas y Oaxaca con distinta experiencia migratoria.

  5. Historias del arte y experiencias pedagógicas

    OpenAIRE

    Muñoz Cobeñas, Leticia Amelia

    2012-01-01

    El presente trabajo intenta articular la experiencia pedagógica con reflexiones en torno a la historia del arte, su renovación teórica y el acercamiento a diferentes mundos empíricos de las llamadas obras de arte. Desde la cátedra Epistemología de las ciencias sociales de la Facultad de Bellas Artes hemos reconocido los aportes interdisciplinares en la definición de una historia del arte que renueva e incorpora nuevas problemáticas y otros objetos de estudio surgidos al interior del propio...

  6. Experiencias y prototipos de aplicaciones de TV Digital interactivas

    OpenAIRE

    Fernanda Daniela Oyarzo; Franco Ramon Herrera; Mirtha Fabiana Miranda; Sandra Isabel Casas

    2014-01-01

    La TV Digital es una tecnología, que va a transformar la experiencia de ver televisión. Imagen y sonido en alta definición junto con la interactividad son posibles gracias al pasaje de la transmisión analógica a la digital, la cual permite enviar datos, video, audio, aplicaciones, etc. a través de los canales de transmisión. Estas señales digitales son más eficientes que las analógicas y tienen como principal ventaja la posibilidad de enviar servicios a través del mismo canal, permitiendo un ...

  7. Movilidad sustentable en Chile: Oportunidades, experiencias locales y referencias globales

    OpenAIRE

    Jorge Díaz Tejeda

    2015-01-01

    Este artículo propone Premisas Conceptuales, Premisas Metodológicas y el desarrollo de Aspectos Estratégicos para la implementación de soluciones a la Movilidad Urbana. Se inspira en las ideas, experiencias e investigaciones de diversas personas quienes abordan desde lógicas puntuales aspectos temáticos específicos en el marco de la Planificación Urbana en general y de las aplicaciones en Transporte en particular. Chile atraviesa por una oportunidad histórica, quizás paradójicamente, a partir...

  8. La experiencia del sufrimiento y la medicina mentis

    Directory of Open Access Journals (Sweden)

    Luis Fernando Cardona Suárez

    2015-05-01

    Full Text Available En el presente artículo se examinala experiencia del sufrimientohumano indicando la actitud másadecuada para enfrentarlo. Setoma distancia de los intentos dehallar una explicación causal quepermita superarlo o simplementeaminorar sus efectos en el conjuntode la vida. Al mirar esta experienciaa la luz de diversas expresiones artísticas,queremos resaltar el papeldel arte para asumir el dolor comouna puerta que nos abre a lo másinterno de nosotros mismos y, conello, del mundo. Esta puerta es, enefecto, una verdadera medicinamentis.

  9. HACIA UNA ORGANIZACIÓN QUE APRENDE: UNA EXPERIENCIA CUBANA

    OpenAIRE

    Armando Cuesta Santos

    2004-01-01

    Se enuncian principios y atributos relativos a la organización que aprende, haciéndose consideraciones sobre su aplicación al adoptarse una definición y arribar a una conducción metodológica buscando hacerla viable en la practica empresarial cubana. Ofrecer una reseña sobre tal viabilidad con las experiencias adquiridas reflejando peculiaridades, constituye el objetivo central de este trabajo, reali...

  10. Educación y envejecimiento activo: una experiencia comunitaria

    OpenAIRE

    Aparicio Alonso, Concepción

    2013-01-01

    La presente tesis doctoral describe una experiencia comunitaria mediante talleres de Educación para la Salud (EpS) (Costa y López, 2008) dirigidos a personas mayores. Contiene diez capítulos divididos en dos partes. En la primera, capítulos uno a cinco, se exponen los fundamentos teóricos de la investigación y en la segunda, capítulos seis a diez, el trabajo de campo realizado. El primer capítulo aborda el fenómeno demográfico denominado envejecimiento de la población y las diversas perspect...

  11. Objetos de aprendizaje: experiencia de curso de posgrado

    OpenAIRE

    Rosanigo, Zulema Beatriz; Bramati, Pedro; Bramati, Silvina

    2012-01-01

    En este artículo se presenta la experiencia desarrollada en el dictado del curso de posgrado sobre “Diseño de materiales en entornos virtuales: Objetos de aprendizaje”. Un Objeto de Aprendizaje “es un recurso docente digital empaquetado conjuntamente con un recubrimiento semántico estandarizado, compatible con diversos ambientes y sistemas de administración de aprendizajes, fácil de migrar de una plataforma a otra, factible de localizar, acceder, archivar y re-utilizar”. El propósito de...

  12. La urdimbre sostenible como argumento proyectual en arquitectura. Experiencias.

    OpenAIRE

    Herrera-Limones, Rafael

    2011-01-01

    La ARQUITECTURA debe nacer como la solución idónea que el LUGAR (en su doble acepción LOCUS1 + SITUS2) nos dicta, en una atenta observación del sitio y las experiencias precedentes. Evidentemente, es el factor climático uno de los más claros elementos que influye -o debería influir- en la configuración final de lo construido. En nuestro caso, es sabido que estamos inmersos en la amplia franja de lo que denominamos clima mediterráneo, el cual, con carácter muy general y de forma amplia, cu...

  13. Campus y ciudad: la experiencia del Barcelona Knowledge Campus

    OpenAIRE

    Roca Blanch, Estanislao

    2011-01-01

    El presente artículo presenta una reflexión sobre los campus y su relación con la ciudad, a través de tópicos e invariantes de modelos de asentamiento y casos paradigmáticos. En estos campus se establecen distintas situaciones y maneras de relación urbana, desde los modelos europeos iniciales, de localización más nítidamente urbana, a modelos anglosajones con localizaciones periurbanas. El artículo continúa con un resumen de la experiencia profesional y académica en el Campus de la Diagon...

  14. Proyecto final de estudios, una experiencia académica

    OpenAIRE

    Puglesi, Alfredo E.; Bernasconi, María Susana

    2011-01-01

    Inserto en la temática de las innovaciones, experiencias e investigación en las tecnologías aplicadas, este trabajo describe la realización del último Proyecto Final de Estudios (PFE) por parte de alumnos de la carrera de Ingeniería en Mecatrónica de la Facultad de Ingeniería de la Universidad Nacional de Cuyo y en el marco del convenio que la misma tiene con la de l'École Nationale d'Ingénieurs de Brest (Francia), mediante el cual, dos alumnos concurren anualmente para cursar los...

  15. El mercado de la poes??a de la experiencia

    OpenAIRE

    Abril Palacios, Juan Carlos

    2014-01-01

    La poes??a de la experiencia ya se considera un asunto a tratar en la historia de la literatura reciente. Hoy en d??a el panorama se ha abierto a otras propuestas est??ticas, pero durante m??s de dos d??cadas esta corriente ha protagonizado un aut??ntico boom de lectores ???y en buena medida de p??blico??? los cuales han disfrutado no s??lo de un g??nero tradicionalmente destinado solo a minor??as, sino que han creado una red comercial en torno a la poes??a de la que otras corrientes menos po...

  16. Molecular-based tumour subtypes of canine mammary carcinomas assessed by immunohistochemistry

    Directory of Open Access Journals (Sweden)

    Sarli Giuseppe

    2010-01-01

    Full Text Available Abstract Background Human breast cancer is classified by gene expression profile into subtypes consisting of two hormone (oestrogen and/or progesterone receptor-positive types (luminal-like A and luminal-like B and three hormone receptor-negative types [human epidermal growth factor receptor 2-expressing, basal-like, and unclassified ("normal-like"]. Immunohistochemical surrogate panels are also proposed to potentially identify the molecular-based groups. The present study aimed to apply an immunohistochemical panel (anti-ER, -PR, -ERB-B2, -CK 5/6 and -CK14 in a series of canine malignant mammary tumours to verify the molecular-based classification, its correlation with invasion and grade, and its use as a prognostic aid in veterinary practice. Results Thirty-five tumours with luminal pattern (ER+ and PR+ were subgrouped into 13 A type and 22 B type, if ERB-B2 positive or negative. Most luminal-like A and basal-like tumours were grade 1 carcinomas, while the percentage of luminal B tumours was higher in grades 2 and 3 (Pearson Chi-square P = 0.009. No difference in the percentage of molecular subtypes was found between simple and complex/mixed carcinomas (Pearson Chi-square P = 0.47. No significant results were obtained by survival analysis, even if basal-like tumours had a more favourable prognosis than luminal-like lesions. Conclusion The panel of antibodies identified only three tumour groups (luminal-like A and B, and basal-like in the dog. Even though canine mammary tumours may be a model of human breast cancer, the existence of the same carcinoma molecular subtypes in women awaits confirmation. Canine mammary carcinomas show high molecular heterogeneity, which would benefit from a classification based on molecular differences. Stage and grade showed independent associations with survival in the multivariate regression, while molecular subtype grouping and histological type did not show associations. This suggests that caution should be

  17. Arylazopyrazoles as Light-Responsive Molecular Switches in Cyclodextrin-Based Supramolecular Systems.

    Science.gov (United States)

    Stricker, Lucas; Fritz, Eva-Corinna; Peterlechner, Martin; Doltsinis, Nikos L; Ravoo, Bart Jan

    2016-04-01

    A simple and high yield synthesis of water-soluble arylazopyrazoles (AAPs) featuring superior photophysical properties is reported. The introduction of a carboxylic acid allows the diverse functionalization of AAPs. Based on structural modifications of the switching unit the photophysical properties of the AAPs could be tuned to obtain molecular switches with favorable photostationary states. Furthermore, AAPs form stable and light-responsive host-guest complexes with β-cyclodextrin (β-CD). Our most efficient AAP shows binding affinities comparable to azobenzenes, but more effective switching and higher thermal stability of the Z-isomer. As a proof-of-principle, we investigated two CD-based supramolecular systems, containing either cyclodextrin vesicles (CDVs) or cyclodextrin-functionalized gold nanoparticles (CDAuNPs), which revealed excellent reversible, light-responsive aggregation and dispersion behavior. To conclude, AAPs have great potential to be incorporated as molecular switches in highly demanding and multivalent photoresponsive systems. PMID:26972671

  18. Important issues facing model-based approaches to tunneling transport in molecular junctions

    CERN Document Server

    Baldea, Ioan

    2015-01-01

    Extensive studies on thin films indicated a generic cubic current-voltage $I-V$ dependence as a salient feature of charge transport by tunneling. A quick glance at $I-V$ data for molecular junctions suggests a qualitatively similar behavior. This would render model-based studies almost irrelevant, since, whatever the model, its parameters can always be adjusted to fit symmetric (asymmetric) $I-V$ curves characterized by two (three) expansion coefficients. Here, we systematically examine popular models based on tunneling barrier or tight-binding pictures and demonstrate that, for a quantitative description at biases of interest ($V$ slightly higher than the transition voltage $V_t$), cubic expansions do not suffice. A detailed collection of analytical formulae as well as their conditions of applicability are presented to facilitate experimentalists colleagues to process and interpret their experimental data by obtained by measuring currents in molecular junctions. We discuss in detail the limits of applicabili...

  19. A density-based adaptive quantum mechanical/molecular mechanical method.

    Science.gov (United States)

    Waller, Mark P; Kumbhar, Sadhana; Yang, Jack

    2014-10-20

    We present a density-based adaptive quantum mechanical/molecular mechanical (DBA-QM/MM) method, whereby molecules can switch layers from the QM to the MM region and vice versa. The adaptive partitioning of the molecular system ensures that the layer assignment can change during the optimization procedure, that is, on the fly. The switch from a QM molecule to a MM molecule is determined if there is an absence of noncovalent interactions to any atom of the QM core region. The presence/absence of noncovalent interactions is determined by analysis of the reduced density gradient. Therefore, the location of the QM/MM boundary is based on physical arguments, and this neatly removes some empiricism inherent in previous adaptive QM/MM partitioning schemes. The DBA-QM/MM method is validated by using a water-in-water setup and an explicitly solvated L-alanyl-L-alanine dipeptide. PMID:24954803

  20. Efficient electronic coupling and improved stability with dithiocarbamate-based molecular junctions

    Science.gov (United States)

    von Wrochem, Florian; Gao, Deqing; Scholz, Frank; Nothofer, Heinz-Georg; Nelles, Gabriele; Wessels, Jurina M.

    2010-08-01

    Molecular electronic devices require stable and highly conductive contacts between the metal electrodes and molecules. Thiols and amines are widely used to attach molecules to metals, but they form poor electrical contacts and lack the robustness required for device applications. Here, we demonstrate that dithiocarbamates provide superior electrical contact and thermal stability when compared to thiols on metals. Ultraviolet photoelectron spectroscopy and density functional theory show the presence of electronic states at 0.6 eV below the Fermi level of Au, which effectively reduce the charge injection barrier across the metal-molecule interface. Charge transport measurements across oligophenylene monolayers reveal that the conductance of terphenyl-dithiocarbamate junctions is two orders of magnitude higher than that of terphenyl-thiolate junctions. The stability and low contact resistance of dithiocarbamate-based molecular junctions represent a significant step towards the development of robust, organic-based electronic circuits.

  1. Sputum-Based Molecular Biomarkers for the Early Detection of Lung Cancer: Limitations and Promise

    International Nuclear Information System (INIS)

    Lung cancer is the leading cause of cancer deaths, with an overall survival of 15% at five years. Biomarkers that can sensitively and specifically detect lung cancer at early stage are crucial for improving this poor survival rate. Sputum has been the target for the discovery of non-invasive biomarkers for lung cancer because it contains airway epithelial cells, and molecular alterations identified in sputum are most likely to reflect tumor-associated changes or field cancerization caused by smoking in the lung. Sputum-based molecular biomarkers include morphology, allelic imbalance, promoter hypermethylation, gene mutations and, recently, differential miRNA expression. To improve the sensitivity and reproducibility of sputum-based biomarkers, we recommend standardization of processing protocols, bronchial epithelial cell enrichment, and identification of field cancerization biomarkers

  2. Development of a molecularly imprinted polymer based surface plasmon resonance sensor for theophylline monitoring

    Science.gov (United States)

    Zheng, Rui; Cameron, Brent D.

    2011-03-01

    Molecularly imprinted polymer (MIP) thin films and surface plasmon resonance (SPR) sensing technologies were combined to develop a novel sensing platform for monitoring real-time theophylline concentration, which is a compound of interest in environmental monitoring and a molecular probe for phenotyping certain cytochrome P450 enzymes. The MIPs hydrogel is easy to synthesize and provides shape-selective recognition with high affinity to specific target molecules. Different polymerization formulas were tested and optimized. The influence of the monomer sensitive factors were addressed by SPR. SPR is an evanescent wave optics based sensing technique that is suitable for real-time and label free sensing purposes. Gold nanorods (Au NRs) were uniformly immobilized onto a SPR sensing surface for the construction of a fiber optics based prism-free localized SPR (LSPR) measurement. This technique can be also applied to assess the activities of other small organic molecules by adjusting the polymerization formula, thus, this approach also has many other potential applications.

  3. Recent emergence of photon upconversion based on triplet energy migration in molecular assemblies.

    Science.gov (United States)

    Yanai, Nobuhiro; Kimizuka, Nobuo

    2016-04-01

    An emerging field of triplet energy migration-based photon upconversion (TEM-UC) is reviewed. Highly efficient photon upconversion has been realized in a wide range of chromophore assemblies, such as non-solvent liquids, ionic liquids, amorphous solids, gels, supramolecular assemblies, molecular crystals, and metal-organic frameworks (MOFs). The control over their assembly structures allows for unexpected air-stability and maximum upconversion quantum yield at weak solar irradiance that has never been achieved by the conventional molecular diffusion-based mechanism. The introduction of the "self-assembly" concept offers a new perspective in photon upconversion research and triplet exciton science, which show promise for numerous applications ranging from solar energy conversion to chemical biology. PMID:26947379

  4. Initiating Heavy-atom Based Phasing by Multi-Dimensional Molecular Replacement

    DEFF Research Database (Denmark)

    Pedersen, Bjørn Panyella; Gourdon, Pontus Emanuel; Liu, Xiangyu;

    2014-01-01

    To obtain an electron-density map from a macromolecular crystal the phase-problem needs to be solved, which often involves the use of heavy-atom derivative crystals and concomitantly the determination of the heavy atom substructure. This is customarily done by direct methods or Patterson......-based approaches, which however may fail when only poorly diffracting derivative crystals are available, as often the case for e.g. membrane proteins. Here we present an approach for heavy atom site identification based on a Molecular Replacement Parameter Matrix (MRPM) search. It involves an n-dimensional search...... to test a wide spectrum of molecular replacement parameters, such as clusters of different conformations. The result is scored by the ability to identify heavy-atom positions, from anomalous difference Fourier maps, that allow meaningful phases to be determined. The strategy was successfully applied...

  5. Plasmon Resonance Energy Transfer (PRET)-based Molecular Imaging of Cytochrome c in Living Cells

    OpenAIRE

    Choi, Yeonho; Kang, Taewook; Lee, Luke P.

    2009-01-01

    We describe the development of innovative plasmon resonance energy transfer (PRET)-based molecular imaging of biomolecules in living cells. Our strategy of in vivo PRET imaging relies on the resonant plasmonic energy transfer from a gold nanoplasmonic probe to conjugated target molecules, which creates “quantized quenching dips” within the Rayleigh scattering spectrum of the probe. The positions of these quantized quenching dips exactly match with the absorption peaks of the target molecule s...

  6. Modeling of Car-Following Required Safe Distance Based on Molecular Dynamics

    OpenAIRE

    Dayi Qu; Xiufeng Chen; Wansan Yang; Xiaohua Bian

    2014-01-01

    In car-following procedure, some distances are reserved between the vehicles, through which drivers can avoid collisions with vehicles before and after them in the same lane and keep a reasonable clearance with lateral vehicles. This paper investigates characters of vehicle operating safety in car following state based on required safe distance. To tackle this problem, we probe into required safe distance and car-following model using molecular dynamics, covering longitudinal and lateral safe...

  7. Molecular-Based Assay for Simultaneous Detection of Four Plasmodium spp. and Wuchereria bancrofti Infections

    OpenAIRE

    MEHLOTRA, RAJEEV K.; Gray, Laurie R; Blood-Zikursh, Melinda J.; Kloos, Zachary; Henry-Halldin, Cara N.; Tisch, Daniel J.; Thomsen, Edward; Reimer, Lisa; Kastens, Will; Baea, Manasseh; Baea, Kaye; Baisor, Moses; Tarongka, Nandao; Kazura, James W; Zimmerman, Peter A

    2010-01-01

    Four major malaria-causing Plasmodium spp. and lymphatic filariasis-causing Wuchereria bancrofti are co-endemic in many tropical and sub-tropical regions. Among molecular diagnostic assays, multiplex polymerase chain reaction (PCR)–based assays for the simultaneous detection of DNAs from these parasite species are currently available only for P. falciparum and W. bancrofti or P. vivax and W. bancrofti. Using a post-PCR oligonucleotide ligation detection reaction–fluorescent microsphere assay ...

  8. Radical Gas-Based DNA Decontamination for Ultra-Sensitive Molecular Experiments

    OpenAIRE

    Morono, Yuki; Yamamoto, Katsuhiro; Inagaki, Fumio

    2012-01-01

    In this study, we tested a radical gas-based decontamination technique to prevent possible DNA contamination by the air and/or equipment used in molecular experiments. We prepared 104 molecules of model DNA contaminant and placed the dried DNA into test tubes, which were then exposed to radical gas. Quantitative PCR analysis showed that, even after a short exposure time of 30 minutes, 99.54% of the model DNA contaminant was effectively decomposed to undetectable levels. Our results demonstrat...

  9. Multi-scale computational framework for evaluating of the performance of molecular based flash cells

    OpenAIRE

    Georgiev, Vihar; Asenov, Asen

    2015-01-01

    In this work we present a multi-scale computational framework for evaluation of statistical variability in a molecular based non-volatile memory cell. As a test case we analyse a BULK flash cell with polyoxometalates (POM) inorganic molecules used as storage centres. We focuse our discussions on the methodology and development of our innovative and unique computational framework. The capability of the discussed multi-scale approach is demonstrated by establishing a link between the threshold ...

  10. Modeling the relationship between body weight and energy intake: A molecular diffusion-based approach

    OpenAIRE

    Gong Zhejun; Gong Zhefeng

    2012-01-01

    Abstract Background Body weight is at least partly controlled by the choices made by a human in response to external stimuli. Changes in body weight are mainly caused by energy intake. By analyzing the mechanisms involved in food intake, we considered that molecular diffusion plays an important role in body weight changes. We propose a model based on Fick's second law of diffusion to simulate the relationship between energy intake and body weight. Results This model was applied to food intake...

  11. Reusable molecular sensor based on photonic activation control of DNA probes

    OpenAIRE

    Nishimura, Takahiro; Ogura, Yusuke; Tanida, Jun

    2012-01-01

    We propose a photoactivatable and resettable molecular sensor using DNA probes. The functionality is achieved by reversible change of DNA structure induced via photonic signals. Based on the mechanism, the sensor can detect target molecules at a desired instant and can be returned to its initial state after detection. The experimental results demonstrate that the concentrations of the target molecules are detected correctly and repeatedly according to the light signal.

  12. Synthetic molecular systems based on porphyrins as models for the study of energy transfer in photosynthesis

    International Nuclear Information System (INIS)

    The published data on the synthesis and photochemical properties of porphyrin-based molecular ensembles which represent models of natural photosynthetic light-harvesting complexes are generalised and systematised. The dependence of the transfer of excitation energy on the distance between donor and acceptor components, their mutual arrangement, electronic and environmental factors are discussed. Two mechanisms of energy transfer reactions, viz., 'through space' and 'through bond', are considered. The bibliography includes 96 references.

  13. Molecular Characterization of Soil Ammonia-Oxidizing Bacteria Based on the Genes Encoding Ammonia Monooxygenase

    OpenAIRE

    Alzerreca, Jose Javier

    1999-01-01

    Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cult...

  14. Cellulose acetate-based molecularly imprinted polymeric membrane for separation of vanillin and o-vanillin

    OpenAIRE

    Chunjing Zhang; Shian Zhong; Zhengpeng Yang

    2008-01-01

    Cellulose acetate-based molecularly imprinted polymeric membranes were prepared using vanillin as template molecule. The microscopic structure of the resultant polymeric membranes was characterized by SEM and FTIR spectroscopy, and the selective binding properties and separation capacity of the membranes for vanillin and o-vanillin were tested with binding experiments and separate experiments, respectively. The results showed that the vanillin-imprinted polymeric membranes displayed higher bi...

  15. Kinetic Energy-Based Temperature Computation in Non-Equilibrium Molecular Dynamics Simulation

    OpenAIRE

    Liu, Bin; Xu, Ran; He, Xiaoqiao

    2009-01-01

    The average kinetic energy is widely used to characterize temperature in molecular dynamics (MD) simulation. In this letter, the applicability of three types of average kinetic energy as measures of temperature is investigated, i.e., the total kinetic energy, kinetic energy without the centroid translation part, and thermal disturbance kinetic energy. Our MD simulations indicate that definitions of temperature based on the kinetic energy including rigid translational or rotational motion may ...

  16. Geometric filters for protein–ligand complexes based on phenomenological molecular models

    OpenAIRE

    Sudakov O. O.; Balinskyi O. M.; Platonov M. O.; Kovalskyy D. B.

    2013-01-01

    Molecular docking is a widely used method of computer-aided drug design capable of accurate prediction of protein-ligand complex conformations. However, scoring functions used to estimate free energy of binding still lack accuracy. Aim. Development of computationally simple and rapid algorithms for ranking ligands based on docking results. Methods. Computational filters utilizing geometry of protein-ligand complex were designed. Efficiency of the filters was verified in a cross-docking study ...

  17. Remote Detection of Xenon-based Molecular Sensors and the Development of Novel Paramagnetic Agents

    OpenAIRE

    Smith, Monica A.

    2012-01-01

    Applications of laser-polarized xenon nuclear magnetic resonance (NMR) spectroscopy and imaging have grown in number due to the exceptional sensitivity of xenon to its local environment. When paired with microfluidic technology, xenon-based molecular sensors (XBMS) have the potential to be used in a broad range of applications from medical devices to geochemistry. Detection of XBMS on a microfluidic chip requires remote detection NMR methodology, where the encoding and detection of aqueous...

  18. Molecular Toxicology of Substances Released from Resin–Based Dental Restorative Materials

    OpenAIRE

    Athina Bakopoulou; Triantafillos Papadopoulos; Pavlos Garefis

    2009-01-01

    Resin-based dental restorative materials are extensively used today in dentistry. However, significant concerns still remain regarding their biocompatibility. For this reason, significant scientific effort has been focused on the determination of the molecular toxicology of substances released by these biomaterials, using several tools for risk assessment, including exposure assessment, hazard identification and dose-response analysis. These studies have shown that substances released by thes...

  19. Prediction of Substrate-Enzyme-Product Interaction Based on Molecular Descriptors and Physicochemical Properties

    OpenAIRE

    Bing Niu; Guohua Huang; Linfeng Zheng; Xueyuan Wang; Fuxue Chen; Yuhui Zhang; Tao Huang

    2013-01-01

    It is important to correctly and efficiently predict the interaction of substrate-enzyme and to predict their product in metabolic pathway. In this work, a novel approach was introduced to encode substrate/product and enzyme molecules with molecular descriptors and physicochemical properties, respectively. Based on this encoding method, KNN was adopted to build the substrate-enzyme-product interaction network. After selecting the optimal features that are able to represent the main factors of...

  20. Las experiencias extracorpóreas y las experiencias alucinatorias: relación con variables cognitivas y perceptuales

    Directory of Open Access Journals (Sweden)

    Alejandro Parra

    2008-12-01

    Full Text Available RESUMENLa experiencia fuera del cuerpo (EFC se define como un experiencia mediante la cual el “yo” o centro de conciencia parece ocupar una posición remota respecto a su propio cuerpo. Un total de 648 estudiantes de psicología que incluyó 78% de mujeres y 24% de hombres, completaron un número de escalas para comparar los puntajes de ambos grupos (con EFC N = 132 vs sin EFC N = 516. Los resultados mostraron mayor esquizotipia cognitivo-perceptual, absorción, disociación, propensidad a la fantasía, tendencia a alucinar, imaginería visual en individuos que tienen EFC en comparación con un grupo control. La incidencia de tales experiencias incluye a individuos que han señalado los efectos benéficos de lasEFCs como un modo adaptativo al estrés postraumático.ABSTRACTAbstract. An out-of-body experience or OBE is one in which the “self” or center of awareness seems to the experient to occupy temporarily a position that is spatially remote from his or her body. A total of 648 undergraduate students population included 76% females and 24% males, and who completed a number of scales. Data for experients of OBE were compared with data for those who did not (experients N= 132 vs. non‑experients N= 516. The results showed a higher level of cognitive-perceptual schizotypy, absorption, dissociation, fantasy and hallucination proneness, and visual imagery in OBErs than in non-OBErs. This study suggest that the dissociational model of OBE. Anomalous perceptual experiences and some subjects report beneficial effects from OBEs in an adaptive way.

  1. Feasibility study of molecular memory device based on DNA using methylation to store information

    Science.gov (United States)

    Jiang, Liming; Qiu, Wanzhi; Al-Dirini, Feras; Hossain, Faruque M.; Evans, Robin; Skafidas, Efstratios

    2016-07-01

    DNA, because of its robustness and dense information storage capability, has been proposed as a potential candidate for next-generation storage media. However, encoding information into the DNA sequence requires molecular synthesis technology, which to date is costly and prone to synthesis errors. Reading the DNA strand information is also complex. Ideally, DNA storage will provide methods for modifying stored information. Here, we conduct a feasibility study investigating the use of the DNA 5-methylcytosine (5mC) methylation state as a molecular memory to store information. We propose a new 1-bit memory device and study, based on the density functional theory and non-equilibrium Green's function method, the feasibility of electrically reading the information. Our results show that changes to methylation states lead to changes in the peak of negative differential resistance which can be used to interrogate memory state. Our work demonstrates a new memory concept based on methylation state which can be beneficial in the design of next generation DNA based molecular electronic memory devices.

  2. Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences

    Directory of Open Access Journals (Sweden)

    Michelle Klein Sercundes

    2016-03-01

    Full Text Available Abstract Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC and beta subunit of RNA polymerase (rpoB, and mitochondrial gene coding for cytochrome B (cytB were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula and Sarcocystis neurona were investigated, along with Neospora caninum, Neospora hughesi, Toxoplasma gondii (strains RH, CTG and PTG, Besnoitia akodoni, Hammondia hammondiand two genetically divergent lineages of Hammondia heydorni. The molecular analysis based on organellar genes did not clearly differentiate between N. caninum and N. hughesi, but the two lineages of H. heydorni were confirmed. Slight differences between the strains of S. falcatula and S. neurona were encountered in all markers. In conclusion, congruent phylogenies were inferred from the three different genes and they might be used for screening undescribed sarcocystid parasites in order to ascertain their phylogenetic relationships with organisms of the family Sarcocystidae. The evolutionary studies based on organelar genes confirm that the genusHammondia is paraphyletic. The primers used for amplification of clpC and rpoB were able to amplify genetic sequences of organisms of the genus Sarcocystisand organisms of the subfamily Toxoplasmatinae as well.

  3. Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences.

    Science.gov (United States)

    Sercundes, Michelle Klein; Valadas, Samantha Yuri Oshiro Branco; Keid, Lara Borges; Oliveira, Tricia Maria Ferreira Souza; Ferreira, Helena Lage; Vitor, Ricardo Wagner de Almeida; Gregori, Fábio; Soares, Rodrigo Martins

    2016-01-01

    Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC) and beta subunit of RNA polymerase (rpoB), and mitochondrial gene coding for cytochrome B (cytB) were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula and Sarcocystis neurona were investigated, along with Neospora caninum, Neospora hughesi, Toxoplasma gondii (strains RH, CTG and PTG), Besnoitia akodoni, Hammondia hammondiand two genetically divergent lineages of Hammondia heydorni. The molecular analysis based on organellar genes did not clearly differentiate between N. caninum and N. hughesi, but the two lineages of H. heydorni were confirmed. Slight differences between the strains of S. falcatula and S. neurona were encountered in all markers. In conclusion, congruent phylogenies were inferred from the three different genes and they might be used for screening undescribed sarcocystid parasites in order to ascertain their phylogenetic relationships with organisms of the family Sarcocystidae. The evolutionary studies based on organelar genes confirm that the genus Hammondia is paraphyletic. The primers used for amplification of clpC and rpoB were able to amplify genetic sequences of organisms of the genus Sarcocystisand organisms of the subfamily Toxoplasmatinae as well. PMID:27007245

  4. Which, when and why? Rational use of tissue-based molecular testing in localized prostate cancer.

    Science.gov (United States)

    Ross, A E; D'Amico, A V; Freedland, S J

    2016-03-01

    An increased molecular understanding of localized prostate cancer and the improved ability for molecular testing of pathologic tissue has led to the development of multiple clinical assays. Here we review the relevant molecular biology of localized prostate cancer, currently available tissue-based tests and describe which is best supported for use in various clinical scenarios. Literature regarding testing of human prostate cancer tissue with Ki-67, PTEN (by immunohistochemistry (IHC) or fluroescence in situ hybridization (FISH)), ProMark, Prolaris, OncotypeDX Prostate and Decipher was reviewed to allow for generation of expert opinions. At diagnosis, evaluation of PTEN status, use of ProMark or OncotypeDX Prostate in men with Gleason 6 or 3+4=7 disease may help guide the use of active surveillance. For men with Gleason 7 or above disease considering watchful waiting, Ki-67 and Prolaris add independent prognostic information. For those men who have undergone prostatectomy and have adverse pathology, Decipher testing may aid in the decision to undergo adjuvant radiation. Newly available molecular tests bring opportunities to improve decision making for men with localized prostate cancer. A review of the currently available data suggests clinical scenarios for which each of these tests may have the greatest utility. PMID:26123120

  5. Characterization-Based Molecular Design of Biofuel Additives Using Chemometric and Property Clustering Techniques

    Directory of Open Access Journals (Sweden)

    Subin eHada

    2014-06-01

    Full Text Available In this work, multivariate characterization data such as infrared (IR spectroscopy was used as a source of descriptor data involving information on molecular architecture for designing structured molecules with tailored properties. Application of multivariate statistical techniques such as principal component analysis (PCA allowed capturing important features of the molecular architecture from complex data to build appropriate latent variable models. Combining the property clustering techniques and group contribution methods (GCM based on characterization data in a reverse problem formulation enabled identifying candidate components by combining or mixing molecular fragments until the resulting properties match the targets. The developed methodology is demonstrated using molecular design of biodiesel additive which when mixed with off-spec biodiesel produces biodiesel that meets the desired fuel specifications. The contribution of this work is that the complex structures and orientations of the molecule can be included in the design, thereby allowing enumeration of all feasible candidate molecules that matched the identified target but were not part of original training set of molecules.

  6. Synchrotron based mass spectrometry to investigate the molecular properties of mineral-organic associations

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Suet Yi; Kleber, Markus; Takahashi, Lynelle K.; Nico, Peter; Keiluweit, Marco; Ahmed, Musahid

    2013-04-01

    Soil organic matter (OM) is important because its decay drives life processes in the biosphere. Analysis of organic compounds in geological systems is difficult because of their intimate association with mineral surfaces. To date there is no procedure capable of quantitatively separating organic from mineral phases without creating artifacts or mass loss. Therefore, analytical techniques that can (a) generate information about both organic and mineral phases simultaneously and (b) allow the examination of predetermined high-interest regions of the sample as opposed to conventional bulk analytical techniques are valuable. Laser Desorption Synchrotron Postionization (synchrotron-LDPI) mass spectrometry is introduced as a novel analytical tool to characterize the molecular properties of organic compounds in mineral-organic samples from terrestrial systems, and it is demonstrated that when combined with Secondary Ion Mass Spectrometry (SIMS), can provide complementary information on mineral composition. Mass spectrometry along a decomposition gradient in density fractions, verifies the consistency of our results with bulk analytical techniques. We further demonstrate that by changing laser and photoionization energies, variations in molecular stability of organic compounds associated with mineral surfaces can be determined. The combination of synchrotron-LDPI and SIMS shows that the energetic conditions involved in desorption and ionization of organic matter may be a greater determinant of mass spectral signatures than the inherent molecular structure of the organic compounds investigated. The latter has implications for molecular models of natural organic matter that are based on mass spectrometric information.

  7. Molecular phylogeny and evolution of Scomber (Teleostei: Scombridae) based on mitochondrial and nuclear DNA sequences

    Institute of Scientific and Technical Information of China (English)

    CHENG Jiao; GAO Tianxiang; MIAO Zhenqing; YANAGIMOTO Takashi

    2011-01-01

    A molecular phylogenetic analysis of the genus Scomber was conducted based on mitochondrial (COI, Cyt b and control region) and nuclear (5S rDNA) DNA sequence data in multigene perspective. A variety of phylogenetic analytic methods were used to clarify the current taxonomic classification and to assess phylogenetic relationships and the evolutionary history of this genus. The present study produced a well-resolved phylogeny that strongly supported the monophyly of Scomber. We confirmed that S. japonicus and S. colias were genetically distinct. Although morphologically and ecologically similar to S. colias, the molecular data showed that S. japonicus has a greater molecular affinity with S. australasicus, which conflicts with the traditional taxonomy. This phyiogenetic pattern was corroborated by the mtDNA data, but incompletely by the nuclear DNA data. Phylogenetic concordance between the mitochondrial and nuclear DNA regions for the basal nodes supports an Atlantic origin for Scomber. The present-day geographic ranges of the species were compared with the resultant molecular phylogeny derived from partition Bayesian analyses of the combined data sets to evaluate possible dispersal routes of the genus. The present-day geographic distribution of Scomber species might be best ascribed to multiple dispersal events. In addition, our results suggest that phylogenies derived from multiple genes and long sequences exhibited improved phylogenetic resolution, from which we conclude that the phylogenetic reconstruction is a reliable representation of the evolutionary history of Scomber.

  8. Mujeres colombianas viviendo con VIH(sida); contextos, experiencias y necesidades de cuidado de enfermería

    OpenAIRE

    Lafaurie, MM.; Zúñiga M.

    2011-01-01

    El objetivo de este estudio ha sido conocer las experiencias vividas y las necesidades de cuidado de enfermería sentidas por mujeres colombianas que viven con VIH/SIDA, con el fin de contar con elementos para encaminar programas y procesos de intervención con perspectiva de género y de derechos, liderados por profesionales de enfermería. Se tuvo en cuenta un diseño cualitativo con base en testimonios narrados mediante entrevistas a profundidad realizadas a 5 mujeres diagnosticadas con VIH, co...

  9. The molecular hydrogen emission around L1551 IRS 5 - Shock-heated molecular gas at the base of the molecular outflow

    Science.gov (United States)

    Yamashita, Takuya; Tamura, Motohide

    1992-01-01

    Spatially resolved observations of the v = 1-0 S(1) molecular hydrogen emission toward L1551 IRS 5 using the grating spectrometer at KPNO are presented. The S(1) emission consists of a ridge component extending toward west along the optical jet from its peak on IRS 5 and a diffuse component which traces the innermost region of the cavity enclosed by the molecular outflow. The ridge component represents shock-heated molecular gas at the root of the optical jet. The diffuse component is too bright to be of scattered origin; it most likely arises from shock-heated gas within the cavity and could represent an acceleration process of the molecular outflow.

  10. UNA EXPERIENCIA DE APRENDIZAJE-SERVICIO EN COMUNIDADES DE APRENDIZAJE

    Directory of Open Access Journals (Sweden)

    Margarita R. Rodríguez-Gallego

    2015-01-01

    Full Text Available Esta investigación describe la experiencia de Aprendizaje-Servicio vivida y desarrollada por 100 estudiantes-servicio de la Universidad de Sevilla, que participaron voluntariamente durante el curso académico 2013-2014y 104 profesionales de centros educativos. Entre los objetivos, valorar el grado de satisfacción de los participantes en el proyecto ApS y conocer supercepcióncomo futurosdocentes. El diseño de la investigación ha sido mixto, por una parte, exploratorio y no experimental (ex post-factopara conocer las opiniones de los estudiantesy, por otra, el método de codificación abierta de la teoría fundamentada a través del análisis de los diariospara conocer las opiniones de los profesionales.Los resultados obtenidos ponen de manifiesto, tanto para estudiantes como profesionales, que esta experiencia de ApS les ha permitido un mejor desarrollo en el ámbito académico al afianzar los conceptos teóricos, así como en el personalalpoder mejorar sushabilidades sociales y comunicativas,en el profesionalpor la adquisición de cualidades y competencias para el ejercicio profesionaly, por último, en el ámbitosocialaltomar conciencia de las desigualdades.

  11. Los derechos de los niños en la experiencia jurídica romana

    Directory of Open Access Journals (Sweden)

    Sebastiano Tafaro

    2009-12-01

    Full Text Available El presente estudio, si bien parte de la premisa de que ciertamente en el derecho romano no existió un elenco de los “derechos de los niños” tal como se encuentra hoy previsto en los diferentes tratados y convenciones internacionales, busca demostrar que los valores que fundamentan tales derechos sí se encontraban, en cambio, presentes en la experiencia jurídica romana, lo que permitía hablar, ya para la época, de un “derecho de nacer” del concebido, cuya tutela se confiaba en forma concurrente a los patres y a la civitas; de un “derecho a la paternidad” o derecho de ser acogido en la familia; de un “derecho al nombre”, con el cual el niño se identificaba en la colectividad y entraba oficialmente en la familia; de un “derecho a la crianza”, esto es, a ser alimentado y criado; además de otras disposiciones dirigidas a la protección jurídica de los niños, tales como la prohibición del trabajo forzado y la prohibición relativa a las convenciones sobre prestaciones laborales, así como el derecho del impúber a ser asistido y protegido por un tutor; sin que pueda perderse de vista, claro está, que tales “derechos” no pueden ser valorados con base en nuestros esquemas, sino de acuerdo con la realidad jurídica de la experiencia romana, que se caracterizó por un sistema abierto de fuentes y que daría vida a principios de indiscutible civilidad jurídica correspondientes a la visión de una sociedad basada en las interacciones entre los derechos del individuo y las formaciones sociales (la primera entre todas, la familia.

  12. Fast screening of ketamine in biological samples based on molecularly imprinted photonic hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Liang [Department of Forensic Science, People' s Public Security University of China, Beijing (China); Meng, Pinjia, E-mail: mengpinjia@163.com [Department of Forensic Science, People' s Public Security University of China, Beijing (China); Zhang, Qingqing; Wang, Yanji [Department of Forensic Science, People' s Public Security University of China, Beijing (China)

    2013-04-10

    Graphical abstract: A novel label-free colorimetric chemosensor: with the increase in the concentration of ketamine, the Bragg diffraction peak of MIPHs gradually shifted to the longer wavelength region. Accompanying the peak shift, the color change of MIPHs was also observed obviously: from green to red. Highlights: ► We developed the label-free colorimetric MIPHs for handy and fast screening of ketamine. ► The obvious color change of MIPHs was observed upon ketamine. ► The MIPHs exhibited good sensing abilities in an aqueous environment. ► The sensing mechanisms of the water-compatible MIPHs were investigated. ► The MIPHs were employed to screening ketamine in real biological samples. -- Abstract: A novel label-free colorimetric chemosensor was developed for handy and fast screening of ketamine with high sensitivity and specificity based on molecularly imprinted photonic hydrogels (MIPHs) that combined the colloidal-crystal with molecular imprinting technique. The unique inverse opal arrays with a thin polymer wall in which the imprinted nanocavities of ketamine moleculars distributed allowed high sensitive, quick responsive, specific detection of the target analyte, and good regenerating ability in an aqueous environment. Due to the hierarchical inverse opal structural characteristics, the specific ketamine molecular recognition process can induce obvious swelling of the MIPHs to be directly transferred into visually perceptible optical signal (change in color) which can be detected by the naked eye through Bragg diffractive shifts of ordered macroporous arrays. In order to enhance the recognition ability in aqueous environments, the MIPHs were designed as water-compatible and synthesized in a water–methanol system. The molecular recognition mechanisms were investigated. The proposed MIPHs were successfully employed to screen trace level ketamine in human urine and saliva samples, exhibiting high sensitivity, rapid response, and specificity in the

  13. Development and Integration of an SSR-Based Molecular Identity Database into Sugarcane Breeding Program

    Directory of Open Access Journals (Sweden)

    Yong-Bao Pan

    2016-04-01

    Full Text Available Sugarcane breeding is very difficult and it takes 12 to 14 years to develop a new cultivar for commercial production. This is because sugarcane varieties are highly polyploid, inter-specific hybrids with 100 to 130 chromosomes that may vary across geographical areas. Other obstacles/constraints include the small size of flowers that may not synchronize but may self-pollinate, difficulty in distinguishing hybrids from self progenies, extreme (G × E interactive effect, and potential variety mis-identification during vegetative propagation and varietal exchange. To help cane breeders circumvent these constraints, a simple sequence repeats (SSR-based molecular identity database has been developed at the United States Department of Agriculture-Agricultural Research Service, Sugarcane Research Unit in Houma, LA. Since 2005, approximately 2000 molecular identities have been constructed for clones of sugarcane and related Saccharum species that cover geographical areas including Argentina, Australia, Bangladesh, China, Colombia, India, Mexico, Pakistan, South Africa, Thailand, USA (Louisiana, Florida, Texas, and Hawaii, and Venezuela. The molecular identity database is updated annually and has been utilized to: (1 provide molecular descriptors to newly registered cultivars; (2 identify in a timely fashion any mislabeled or unidentifiable clones from cross parents and field evaluation plots; (3 develop de novo clones of energy cane with S. spontaneum cytoplasm; (4 provide clone-specific fingerprint information for assessing cross quality and paternity of polycross; (5 determine genetic relatedness of parental clones; (6 select F1 hybrids from (elite × wild or (wild × elite crosses; and (7 investigate the inheritance of SSR markers in sugarcane. The integration of the molecular identity database into the sugarcane breeding program may improve the overall efficacy of cultivar development and commercialization.

  14. DART: Denoising Algorithm based on Relevance network Topology improves molecular pathway activity inference

    Directory of Open Access Journals (Sweden)

    Purushotham Arnie

    2011-10-01

    Full Text Available Abstract Background Inferring molecular pathway activity is an important step towards reducing the complexity of genomic data, understanding the heterogeneity in clinical outcome, and obtaining molecular correlates of cancer imaging traits. Increasingly, approaches towards pathway activity inference combine molecular profiles (e.g gene or protein expression with independent and highly curated structural interaction data (e.g protein interaction networks or more generally with prior knowledge pathway databases. However, it is unclear how best to use the pathway knowledge information in the context of molecular profiles of any given study. Results We present an algorithm called DART (Denoising Algorithm based on Relevance network Topology which filters out noise before estimating pathway activity. Using simulated and real multidimensional cancer genomic data and by comparing DART to other algorithms which do not assess the relevance of the prior pathway information, we here demonstrate that substantial improvement in pathway activity predictions can be made if prior pathway information is denoised before predictions are made. We also show that genes encoding hubs in expression correlation networks represent more reliable markers of pathway activity. Using the Netpath resource of signalling pathways in the context of breast cancer gene expression data we further demonstrate that DART leads to more robust inferences about pathway activity correlations. Finally, we show that DART identifies a hypothesized association between oestrogen signalling and mammographic density in ER+ breast cancer. Conclusions Evaluating the consistency of prior information of pathway databases in molecular tumour profiles may substantially improve the subsequent inference of pathway activity in clinical tumour specimens. This de-noising strategy should be incorporated in approaches which attempt to infer pathway activity from prior pathway models.

  15. Fast screening of ketamine in biological samples based on molecularly imprinted photonic hydrogels

    International Nuclear Information System (INIS)

    Graphical abstract: A novel label-free colorimetric chemosensor: with the increase in the concentration of ketamine, the Bragg diffraction peak of MIPHs gradually shifted to the longer wavelength region. Accompanying the peak shift, the color change of MIPHs was also observed obviously: from green to red. Highlights: ► We developed the label-free colorimetric MIPHs for handy and fast screening of ketamine. ► The obvious color change of MIPHs was observed upon ketamine. ► The MIPHs exhibited good sensing abilities in an aqueous environment. ► The sensing mechanisms of the water-compatible MIPHs were investigated. ► The MIPHs were employed to screening ketamine in real biological samples. -- Abstract: A novel label-free colorimetric chemosensor was developed for handy and fast screening of ketamine with high sensitivity and specificity based on molecularly imprinted photonic hydrogels (MIPHs) that combined the colloidal-crystal with molecular imprinting technique. The unique inverse opal arrays with a thin polymer wall in which the imprinted nanocavities of ketamine moleculars distributed allowed high sensitive, quick responsive, specific detection of the target analyte, and good regenerating ability in an aqueous environment. Due to the hierarchical inverse opal structural characteristics, the specific ketamine molecular recognition process can induce obvious swelling of the MIPHs to be directly transferred into visually perceptible optical signal (change in color) which can be detected by the naked eye through Bragg diffractive shifts of ordered macroporous arrays. In order to enhance the recognition ability in aqueous environments, the MIPHs were designed as water-compatible and synthesized in a water–methanol system. The molecular recognition mechanisms were investigated. The proposed MIPHs were successfully employed to screen trace level ketamine in human urine and saliva samples, exhibiting high sensitivity, rapid response, and specificity in the

  16. Electron induced conformational changes of an imine-based molecular switch on a Au(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Lotze, Christian; Henningsen, Nils; Franke, Katharina; Schulze, Gunnar; Pascual, Jose Ignacio [Inst. f. Experimentalphysik, Freie Universitaet Berlin (Germany); Luo, Ying; Haag, Rainer [Inst. f. Organische Chemie, Freie Universitaet Berlin (Germany)

    2009-07-01

    Azobenzene-based molecules exhibit a cis-trans configurational photoisomerisation in solution. Recently, the adsorption properties of azobenzene derivatives have been investigated on different metal surfaces in order to explore the possible changes in the film properties induced by external stimuli. In azobenzene, the diazo-bridge is a key group for the isomerization process. Its interaction with a metal surface is dominated through the N lone-pair electrons, which reduces the efficiency of the conformational change. In order to reduce the molecule-surface interaction, we explore an alternative molecular architecture by substituting the diazo-bridge (-N=N-) of azobenzene by an imine-group (-N=CH-). We have investigated the imine-based compound para-carboxyl-di-benzene-imine (PCI) adsorbed on a Au(111) surface. The carboxylic terminations mediates the formation of strongly bonded molecular dimers, which align in ordered rows preferentially following the fcc regions of the Au(111) herringbone reconstruction. Low temperature scanning tunneling microscopy was used to induce conformational changes between trans and cis state of individual molecules in a molecular monolayer.

  17. Titanium compounds as catalysts of higher alpha-olefin-based super-high-molecular polymers synthesis

    Science.gov (United States)

    Konovalov, K. B.; Kazaryan, M. A.; Manzhay, V. N.; Vetrova, O. V.

    2016-01-01

    The synthesis of polymers of 10 million or more molecular weight is a difficult task even in a chemical lab. Higher α-olefin-based polymer agents of such kind have found a narrow but quite important niche, the reduction of drag in the turbulent flow of hydrocarbon fluids such as oil and oil-products. In its turn, searching for a catalytic system capable to produce molecules of such a high length and to synthesize polymers of a low molecular-mass distribution is part of a global task of obtaining a high-quality product. In this paper we had observed a number of industrial catalysts with respect to their suitability for higher poly-α- olefins synthesis. A number samples representing copolymers of 1-hexene with 1-decene obtained on a previous generation catalyst, a microsphere titanium chloride catalytic agent had been compared to samples synthesized using a titanium-magnesium catalyst both in solution and in a polymer medium.

  18. Surface plasmon resonance based optical fiber riboflavin sensor by using molecularly imprinted gel

    Science.gov (United States)

    Verma, Roli; Gupta, Banshi D.

    2013-05-01

    We report the fabrication and characterization of surface plasmon resonance (SPR) based optical fiber riboflavin/vitamin B2 sensor using combination of colloidal crystal templating and molecularly imprinted gel. The sensor works on spectral interrogation method. The operating range of the sensor lies from 0 μg/ml to 320 μg/ml, the suitable amount of intakes of riboflavin recommended for different age group. The SPR spectra show blue shift with increasing concentration of riboflavin, which is due to the interaction of riboflavin molecule over specific binding sites caused by molecular imprinting. The present sensor has many advantageous features such as fast response, small probe size, low cost and can be used for remote/online monitoring.

  19. Single molecular switch based on thiol tethered iron(II)clathrochelate on gold

    International Nuclear Information System (INIS)

    Molecular electronics has been associated with high density nano-electronic devices. Developments of molecular electronic devices were based on reversible switching of molecules between the two conductive states. In this paper, self-assembled monolayers of dodecanethiol (DDT) and thiol tethered iron(II)clathrochelate (IC) have been prepared on gold film. The electrochemical and electronic properties of IC molecules inserted into the dodecanethiol monolayer (IC-DDT SAM) were investigated using voltammetric, electrochemical impedance spectroscopy (EIS), scanning tunneling microscopy (STM) and cross-wire tunneling measurements. The voltage triggered switching behaviour of IC molecules on mixed SAM was demonstrated. Deposition of polyaniline on the redox sites of IC-DDT SAM using electrochemical polymerization of aniline was performed in order to confirm that this monolayer acts as nano-patterned semiconducting electrode surface.

  20. Electron induced conformational changes of imine-based molecular switches on a Au(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Lotze, Christian; Pascual, Jose Ignacio [Inst. f. Experimentalphysik, Freie Universitaet Berlin (Germany); Luo, Ying; Haag, Rainer [Inst. f. Organische Chemie, Freie Universitaet Berlin (Germany)

    2010-07-01

    Organic molecules exhibiting controllable reversible transitions between isomeric states on surfaces promise an enormous potential in the field of molecular electronics. The reversible cis-trans isomerization of azobenzene-like molecules is often hindered by a strong interaction of the nitrogen lone-pair electrons of the di-azo bridge (-N=N-) with the substrate. In order to improve the isomerization capabilities, the di-azo bridge is substituted by an imine-group (-N=CH-). Here, we use low-temperature scanning tunneling microscopy to investigate a sub-monolayer of the newly designed imine-based molecular switch NPCI on a Au(111) surface. Its carboxylic termination mediates the formation of hydrogen-bonded dimers, which align in rows along the herringbone reconstruction. We were able to induce reversible conformational changes with the tunneling electrons from the STM tip and determine its efficiency as a function of electron energy.

  1. A nitrogen-vacancy spin based molecular structure microscope using multiplexed projection reconstruction

    CERN Document Server

    Lazariev, Andrii

    2015-01-01

    Methods and techniques to measure and image beyond the state-of-the-art have always been influential in propelling basic science and technology. Because current technologies are venturing into nanoscopic and molecular-scale fabrication, atomic-scale measurement techniques are inevitable. One such emerging sensing method uses the spins associated with nitrogen-vacancy (NV) defects in diamond. The uniqueness of this NV sensor is its atomic size and ability to perform precision sensing under ambient conditions conveniently using light and microwaves (MW). These advantages have unique applications in nanoscale sensing and imaging of magnetic fields from nuclear spins in single biomolecules. During the last few years, several encouraging results have emerged towards the realization of an NV spin-based molecular structure microscope. Here, we present a projection-reconstruction method that retrieves the three-dimensional structure of a single molecule from the nuclear spin noise signatures. We validate this method ...

  2. Molecular Solutions for the Set-Partition Problem on Dna-Based Computing

    Directory of Open Access Journals (Sweden)

    Sientang Tsai

    2013-12-01

    Full Text Available Consider that the every element in a finite set S h aving q elements is a positive integer. The set-par tition problem is to determine whether there is a subset T ⊆ S such that , ∑ ∑ ∈ ∈ = T x T x x x where T = { x| x ∈ S and x ∉ T } . This research demonstrates that molecular operati ons can be applied to solve the set-partition problem. In order to perform this goal, we offer tw o DNA-based algorithms, an unsigned parallel adder and a parallel Exclusive-OR (XOR operation, that f ormally demonstrate our designed molecular solution s for solving the set-partition problem.

  3. Determination of Quantum Chemistry Based Force Fields for Molecular Dynamics Simulations of Aromatic Polymers

    Science.gov (United States)

    Jaffe, Richard; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Ab initio quantum chemistry calculations for model molecules can be used to parameterize force fields for molecular dynamics simulations of polymers. Emphasis in our research group is on using quantum chemistry-based force fields for molecular dynamics simulations of organic polymers in the melt and glassy states, but the methodology is applicable to simulations of small molecules, multicomponent systems and solutions. Special attention is paid to deriving reliable descriptions of the non-bonded and electrostatic interactions. Several procedures have been developed for deriving and calibrating these parameters. Our force fields for aromatic polyimide simulations will be described. In this application, the intermolecular interactions are the critical factor in determining many properties of the polymer (including its color).

  4. The meanings of quality of life: interpretative analysis based on experiences of people in burns rehabilitation Significados para la calidad de vida: análisis interpretativo fundamentado en la experiencia de personas quemadas em rehabilitación Significados de qualidade de vida: análise interpretativa baseada na experiência de pessoas em reabilitação de queimaduras

    Directory of Open Access Journals (Sweden)

    Maria Cristina Silva Costa

    2008-04-01

    Full Text Available This research aimed to interpret the meanings of quality of life, taking into consideration the meanings attributed by those who have undergone serious burns, their experiences and social/cultural background. We used the ethnographic method based on modern hermeneutics. Nineteen patients with burn sequelae, already discharged from the Burns Unit of the Ribeirão Preto Medical School Clinical Hospital participated in this study, along with their relatives. Participants belong to the working class, are between 18 to 50 years old and have been in rehabilitation for at least a year. Data were collected by direct observation and semi-structured interviews. The analysis was processed through the identification of units of meanings and construction of thematic nucleuses. Patients and relatives reported that quality of life had changed because of physical and psychological limitations caused by the burns. The meanings of quality of life are associated with the performance of social roles and are guided by family, work, normality, autonomy and social integration.Con el objetivo de interpretar los significados para la calidad de vida, este estudio parte de la atribución dada por personas que sufrieron quemaduras graves, sus experiencias y su contexto sociocultural. El método etnográfico fue utilizado apoyado en la teoría hermenéutica moderna. Participaron del estudio 19 pacientes con secuelas de quemadura y sus familiares, atendidos en la Unidad de Quemados del Hospital de Clínicas de la Facultad de Medicina de Ribeirão Preto. Los sujetos pertenecían al sector popular, con edades entre 18 y 50 años, participantes del programa de rehabilitación por lo menos un año. Los datos recolectados a través de entrevistas semi-estructuradas y observación directa; siendo su análisis realizado a través de la identificación de unidades de significados y construcción de núcleos temáticos. Los pacientes y sus familiares mencionaron cambios en su calidad

  5. A molecular beacon-based DNA switch for reversible pH sensing in vesicles and live cells.

    Science.gov (United States)

    Narayanaswamy, Nagarjun; Nair, Raji R; Suseela, Y V; Saini, Deepak Kumar; Govindaraju, T

    2016-07-01

    In this Communication, a molecular beacon-based DNA switch (LMB) is developed as an efficient and reversible pH sensing probe. Remarkably, LMB exhibited reversible structural transition between the closed (molecular beacon) and open (A-motif) states very efficiently in synthetic vesicles and live cells without the need for any transfection agents. PMID:27338808

  6. Rectifying Properties of a Nitrogen/Boron-Doped Capped-Carbon-Nanotube-Based Molecular Junction

    Institute of Scientific and Technical Information of China (English)

    ZHAO Peng; LIU De-Sheng; ZHANG Ying; WANG Pei-Ji; ZHANG Zhong

    2011-01-01

    @@ Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbonnanotube-based molecular junction.Obvious rectifying behavior is observed and it is strongly dependent on the doping site.The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer.Moreover, the rectifying performance can be further improved by adjusting the distance between the Cso nanotube caps.%Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbon-nanotube-based molecular junction. Obvious rectifying behavior is observed and it is strongly dependent on the doping site. The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer. Moreover, the rectifying performance can be further improved by adjusting the distance between the C60 nanotube caps.

  7. High performance computing for three-dimensional agent-based molecular models.

    Science.gov (United States)

    Pérez-Rodríguez, G; Pérez-Pérez, M; Fdez-Riverola, F; Lourenço, A

    2016-07-01

    Agent-based simulations are increasingly popular in exploring and understanding cellular systems, but the natural complexity of these systems and the desire to grasp different modelling levels demand cost-effective simulation strategies and tools. In this context, the present paper introduces novel sequential and distributed approaches for the three-dimensional agent-based simulation of individual molecules in cellular events. These approaches are able to describe the dimensions and position of the molecules with high accuracy and thus, study the critical effect of spatial distribution on cellular events. Moreover, two of the approaches allow multi-thread high performance simulations, distributing the three-dimensional model in a platform independent and computationally efficient way. Evaluation addressed the reproduction of molecular scenarios and different scalability aspects of agent creation and agent interaction. The three approaches simulate common biophysical and biochemical laws faithfully. The distributed approaches show improved performance when dealing with large agent populations while the sequential approach is better suited for small to medium size agent populations. Overall, the main new contribution of the approaches is the ability to simulate three-dimensional agent-based models at the molecular level with reduced implementation effort and moderate-level computational capacity. Since these approaches have a generic design, they have the major potential of being used in any event-driven agent-based tool. PMID:27372059

  8. Molecular dynamics simulation based on the multi-component molecular orbital method: Application to H5O2+,D5O2+,andT5O2+

    International Nuclear Information System (INIS)

    Graphical abstract: Molecular dynamics method based on multi-component molecular orbital method was applied to basic hydrogen bonding systems, H5O2+, and its isotopomers (D5O2+andT5O2+). Highlights: ► Molecular dynamics method with nuclear quantum effect was developed. ► Multi-component molecular orbital method was used as ab initio MO calculation. ► Developed method applied to basic hydrogen bonding system, H5O2+, and isotopomers. ► O⋯O vibrational stretching reflected to the distribution of protonic wavefunctions. ► H/D/T isotope effect was also analyzed. - Abstract: We propose a molecular dynamics (MD) method based on the multi-component molecular orbital (MCMO) method, which takes into account the quantum effect of proton directly, for the detailed analyses of proton transfer in hydrogen bonding system. The MCMO based MD (MCMO-MD) method is applied to the basic structures, H5O2+ (called “Zundel ion”), and its isotopomers (D5O2+andT5O2+). We clearly demonstrate the geometrical difference of hydrogen bonded O⋯O distance induced by H/D/T isotope effect because the O⋯O in H-compound was longer than that in D- or T-compound. We also find the strong relation between stretching vibration of O⋯O and the distribution of hydrogen bonded protonic wavefunction because the protonic wavefunction tends to delocalize when the O⋯O distance becomes short during the dynamics. Our proposed MCMO-MD simulation is expected as a powerful tool to analyze the proton dynamics in hydrogen bonding systems.

  9. Generalized energy-based fragmentation approach and its applications to macromolecules and molecular aggregates.

    Science.gov (United States)

    Li, Shuhua; Li, Wei; Ma, Jing

    2014-09-16

    Conspectus The generalized energy-based fragmentation (GEBF) approach provides a very simple way of approximately evaluating the ground-state energy or properties of a large system in terms of ground-state energies of various small "electrostatically embedded" subsystems, which can be calculated with any traditional ab initio quantum chemistry (X) method (X = Hartree-Fock, density functional theory, and so on). Due to its excellent parallel efficiency, the GEBF approach at the X theory level (GEBF-X) allows full quantum mechanical (QM) calculations to be accessible for systems with hundreds and even thousands of atoms on ordinary workstations. The implementation of the GEBF approach at various theoretical levels can be easily done with existing quantum chemistry programs. This Account reviews the methodology, implementation, and applications of the GEBF-X approach. This method has been successfully applied to optimize the structures of various large systems including molecular clusters, polypeptides, proteins, and foldamers. Such investigations could allow us to elucidate the origin and nature of the cooperative interaction in secondary structures of long peptides or the driving force of the self-assembly processes of aromatic oligoamides. These GEBF-based QM calculations reveal that the structures and stability of various complex systems result from a subtle balance of many types of noncovalent interactions such as hydrogen bonding and van der Waals interactions. The GEBF-based ab initio molecular dynamics (AIMD) method also allows the investigation of dynamic behaviors of large systems on the order of tens of picoseconds. It was demonstrated that the conformational dynamics of two model peptides predicted by GEBF-based AIMD are noticeably different from those predicted by the classical force field MD method. With the target of extending QM calculations to molecular aggregates in the condensed phase, we have implemented the GEBF-based multilayer hybrid models

  10. Guest-responsive structural adaptation of a rationally-designed molecular tweezer based on Tröger’s base

    Indian Academy of Sciences (India)

    Ishita Neogi; Alankriti Bajpai; Jarugu Narasimha Moorthy

    2014-09-01

    We have designed and synthesized a modified Tröger’s base TB in which the sterically-rigidified aryl rings that protrude into its groove were envisaged to preclude self-inclusion. From a limited preliminary experimentation, TB has been found to exhibit guest inclusion. The X-ray determined structures of the crystals of guest-free TB and its inclusion compounds with acetonitrile and -dichlorobenzene reveal remarkable adaptability of the TB core to undergo subtle structural changes in response to the guest that is included. The structural analyses demonstrate the fact that TB behaves like a molecular tweezer.

  11. La importancia de la determinación del Factor X activado para la anticoagulación con heparinas de bajo peso molecular: Experiencia en el Hospital San Juan de Dios, 2009-2011 (Primer Reporte The importance of the determination of Factor X acivated for anticoagulation with low molecular weight heparins experience at the Hospital San Juan de Dios. (First report 2009-2011

    Directory of Open Access Journals (Sweden)

    Lizbeth Salazar-Sanchez

    2012-12-01

    receive therapy with low molecular weight heparins (LMWH. This report gives evidence about the importance of determining the activity of Anti-Xa activity for monitoring enoxaparin and for identifying those patients who need this analysis based on some risk factors. Methods: We studied 34 adult patients who received enoxaparin as anticoagulation therapy during the period 2009- 2011. We performed a descriptive analysis of demographic and clinical characteristics of all patients, indicating the reasons for anticoagulation, comorbidities and type of anticoagulation. We determined the anti-Xa activity 4 hours after administration of enoxaparin. Results: The mean age of patients was 62,3 + 17,7 years, regardless of gender. 72,7% of patients received enoxaparin as therapy for an acute coronary syndrome. The most frequent comorbidity was hypertension. The average of renal clearance was 62,47 ml/min, only three patients had a renal clearance below 30 ml/min. 44,1% of the patients were obese. 55, 9% of patients were within therapeutic levels of anti Xa activity and 35,3% of patients had an anti-Xa activity considered as prophylactic. Conclusion: The management of adult patients receiving anticoagulation therapy with LMWH is complex and it is reflected in their demographic and clinical characteristics. It is important to determine Anti-Xa activity to monitor the use of enoxaparin as anticoagulant therapy because of the high variability found in certain groups of patients.

  12. DNA molecular wire-based nanoelectronics: New insight and high frequency AC electrical characterization

    Science.gov (United States)

    Wibowo, Denni Ari

    While recent research in electron-transport mechanism on a double strands DNA seems to converge into a consensus, experiments in direct electrical measurements on a long DNA molecules still lead to a conflicting result. This research investigates experimentally the attachment of DNA molecular wire to high aspect ratio three-dimensional (3D) metal electrode and the effect of temperature to its AC electrical conductivity. The 3-D microelectrode was built on a silicone oxide substrate using patterned thick layers of negative tone photoresist covered by sputtered gold on the top surface. Attachment of lambda-DNA to the microelectrode was demonstrated using oligonucleotide-DNA phosphate backbone ligation and thiol-gold covalent bonding. Electrical characterizations based on I-V and AC impedance analysis of several repeatable data points of attachment with varying lambda-DNA concentration (500 ng/microL to 0.0625 ng/microL) showed measurable and significant conductivity of lambda-DNA molecular wires. Further study was carried out by measuring I-V and impedance while ramping up the temperature to reach complete denaturation (~1100C) resulting in no current transduction. Subsequent re-annealing of the DNA through incubation in TM buffer at annealing temperature (~900C) resulted in recovery of electrical conduction, providing a strong proof that DNA molecular wire is the one generate the electrical conductivity. lambda-DNA molecular wires reported to have differing impedance response at two temperature regions: impedance increases (conductivity decrease) between 40C -- 400C, and then decreases from 400C until DNA completely denatured (~1100C). The increase conductivity after 400C is an experimental support the long distance electron transport mechanism referred as "thermal hopping" mechanism. We believe that this research represents a significant departure from previous studies and makes unique contributions through (i) modification of DNA attachment methods has increase

  13. Systematic studies of Australian stipoid grasses (Austrostipa based on micro-morphological and molecular characteristics

    Directory of Open Access Journals (Sweden)

    BETTY MAULIYA BUSTAM

    2010-01-01

    Full Text Available Bustam BM (2010 Systematic studies of Australian stipoid grasses (Austrostipa based on micro-morphological and molecular characteristics. Biodiversitas 11: 9-14. This research is one of many studies on stipoid grasses organized by the International Stipeae Working Group (ISWG. This research tested the subgeneric classification of Austrostipa proposed by Jacobs and Everett (1996 and tested how informative the micro morphological characters used. Data were collected from herbarium specimens of 36 species (33 species of Austrostipa, two species of Hesperostipa and one species of Anemanthele at Royal Botanic Gardens, Sydney. Twenty eight micro morphological characters were used. The data were collected from both adaxial and abaxial surfaces of leaves, and from the lemma epidermis using a scanning electron microscope (SEM. ISWG provided the molecular data. Parsimony analysis and a distance method (Unweighteic Pair Group with Arithmatic Mean: UPGMA were used to analyze mico morphological and molecular data separately. Only UPGMA analysis was used to analyze the combined data. The results support the monophyly of Austrostipa. However, there is a little support for the subgeneric classification of Austrostipa proposed by Jacobs and Everett (1996, other than for the consistent recognition of Falcatae. The characters for comparisons between genera are too homoplasious at this level and do not contain enough information for analyses at subgeneric level, a problem apparently shared with the DNA sequences.

  14. Mass-spectrometry-based molecular characterization of extracellular vesicles: lipidomics and proteomics.

    Science.gov (United States)

    Kreimer, Simion; Belov, Arseniy M; Ghiran, Ionita; Murthy, Shashi K; Frank, David A; Ivanov, Alexander R

    2015-06-01

    This review discusses extracellular vesicles (EVs), which are submicron-scale, anuclear, phospholipid bilayer membrane enclosed vesicles that contain lipids, metabolites, proteins, and RNA (micro and messenger). They are shed from many, if not all, cell types and are present in biological fluids and conditioned cell culture media. The term EV, as coined by the International Society of Extracellular Vesicles (ISEV), encompasses exosomes (30-100 nm in diameter), microparticles (100-1000 nm), apoptotic blebs, and other EV subsets. EVs have been implicated in cell-cell communication, coagulation, inflammation, immune response modulation, and disease progression. Multiple studies report that EV secretion from disease-affected cells contributes to disease progression, e.g., tumor niche formation and cancer metastasis. EVs are attractive sources of biomarkers due to their biological relevance and relatively noninvasive accessibility from a range of physiological fluids. This review is focused on the molecular profiling of the protein and lipid constituents of EVs, with emphasis on mass-spectrometry-based "omic" analytical techniques. The challenges in the purification and molecular characterization of EVs, including contamination of isolates and limitations in sample quantities, are discussed along with possible solutions. Finally, the review discusses the limited but growing investigation of post-translational modifications of EV proteins and potential strategies for future in-depth molecular characterization of EVs. PMID:25927954

  15. Molecular profiling for genetic variability in Capsicum species based on ISSR and RAPD markers.

    Science.gov (United States)

    Thul, Sanjog T; Darokar, Mahendra P; Shasany, Ajit K; Khanuja, Suman P S

    2012-06-01

    The taxonomic identity of Capsicum species is found to be difficult as it displays variations at morpho-chemical characters. Twenty-two accessions of six Capsicum species, namely, C. annuum, C. baccatum, C. chinense, C. eximium, C. frutescens, and C. luteum were investigated for phenotypic diversity based on flower color and for genetic differences by molecular makers. The genetic cluster analyses of 27 RAPD and eight ISSR primers, respectively, revealed genetic similarities in the ranges of 23-88% and 11-96%. Principal component analysis of the pooled RAPD and ISSR data further supports the genetic similarity and groupings. Different species showed variations in relation to corolla shade of flower. C. annuum accessions formed a single cluster in the molecular analysis as maintaining their flower characteristic. C. chinense accession shared flower features with the accessions of C. frutescens and were found to be closer at genotypic level. C. luteum was found to be rather closer to C. baccatum complex, both phenotypically and genetically. The only accession of C. eximium presenting purple flowers falls apart from the groupings. The floral characteristics and the molecular markers are found to be useful toward the delineation of the species specificity in Capsicum collection and identification of genetic stock. PMID:21861246

  16. Molecular phylogeny of the lionfish genera Dendrochirus and Pterois (Scorpaenidae, Pteroinae) based on mitochondrial DNA sequences.

    Science.gov (United States)

    Kochzius, Marc; Söller, Rainer; Khalaf, Maroof A; Blohm, Dietmar

    2003-09-01

    This study investigates the molecular phylogeny of seven lionfishes of the genera Dendrochirus and Pterois. MP, ML, and NJ phylogenetic analysis based on 964 bp of partial mitochondrial DNA sequences (cytochrome b and 16S rDNA) revealed two main clades: (1) "Pterois" clade (Pterois miles and Pterois volitans), and (2) "Pteropterus-Dendrochirus" clade (remainder of the sampled species). The position of Dendrochirus brachypterus either basal to the main clades or in the "Pteropterus-Dendrochirus" clade cannot be resolved. However, the molecular phylogeny did not support the current separation of the genera Pterois and Dendrochirus. The siblings P. miles and P. volitans are clearly separated and our results support the proposed allopatric or parapatric distribution in the Indian and Pacific Ocean. However, the present analysis cannot reveal if P. miles and P. volitans are separate species or two populations of a single species, because the observed separation in different clades can be either explained by speciation or lineage sorting. Molecular clock estimates for the siblings P. miles and P. volitans suggest a divergence time of 2.4-8.3 mya, which coincide with geological events that created vicariance between populations of the Indian and Pacific Ocean. PMID:12927126

  17. Computational prediction and experimental selectivity coefficients for hydroxyzine and cetirizine molecularly imprinted polymer based potentiometric sensors

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Possible configurations template/monomer complexes were designed and optimized. •Effect of the electrostatic force on the selectivity of MIPs was investigated. •A correlation between selectivity of sensors and a charge distribution was obtained. -- Abstract: In spite of the increasing usages number of molecularly imprinted polymers (MIPs) in many scientific applications, the theoretical aspects of participating intra molecular forces are not fully understood. This work investigates effects of the electrostatic force, the Mulliken charge and the role of cavity's backbone atoms on the selectivity of MIPs. Moreover, charge distribution, which is a computational parameter, was proposed for the prediction of the selectivity coefficients of MIP-based sensors. In the computational approaches and experimental study, methacrylic acid (MAA) was chosen as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linker for hydroxyzine and cetirizine imprinted polymers. Ab initio, DFT B3LYP method was carried out on molecular optimization. With regard to results obtained from molecules optimization and hydrogen bonding properties, possible configurations of 1:n (n ≤ 5) template/monomer complexes were designed and optimized. The binding energy for each complex in gas phase was calculated. Depending on the most stable configuration, hydroxyzine and cetirizine imprinted polymer models were designed. The calculations including the porogen were also investigated. The theoretical charge distributions for the template and some potential interfering molecules were calculated. The results showed a correlation between the selectivity coefficients and the theoretical charge distributions. The results surprisingly show that charge distribution based model was able to predict the selectivity coefficients of MIP based potentiometric sensors

  18. Detergent-dispersant additives based on high-molecular-weight alkylphenols

    Energy Technology Data Exchange (ETDEWEB)

    Kulieva, K.N.; Namazova, I.I.; Ismailova, N.D.; Dorokhina, I.V.

    1988-09-01

    This article describes the synthesis and investigation of Mannich bases produced for alkylphenols, obtained in turn from ethylene oligomers. These oligomers are the still bottoms from distillation products of high-temperature oligomerization of ethylene in the presence of triethylaluminum. Two narrow cuts obtained from the distillation of oligomer fraction were used to study the influence of ethylene oligomer molecular weight on the properties of the additives. The additives were blended in DS-11 oil to evaluate their detergency-dispersancy and other properties. Comparison blends were made with succinimide additives based on the same ethylene oligomers. The Mannich bases give improvements in the oxidation resistance, anticorrosion properties, and detergency-dispersancy of the DS-11 diesel oil.

  19. Comparative Molecular Mechanics and Quantum Mechanics Study of Microhydration of Nucleic Acid Bases

    CERN Document Server

    Lino, J; Deriabina, A; Velasco, M; Poltev, V

    2013-01-01

    DNA is the most important biological molecule, and its hydration contributes essentially to the structure and functions of the double helix. We analyze the microhydration of the individual bases of nucleic acids and their methyl derivatives using methods of molecular mechanics (MM) with the Poltev-Malenkov (PM), AMBER and OPLS force fields, as well as ab initio Quantum Mechanics (QM) calculations at MP2/6-31G(d,p) level of theory. A comparison is made between the calculated interaction energies and the experimental enthalpies of microhydration of bases, obtained from mass spectrometry at low temperatures. Each local water-base interaction energy minimum obtained with MM corresponds to the minimum obtained with QM. General qualitative agreement was observed in the geometrical characteristics of the local minima obtained via the two groups of methods. MM minima correspond to slightly more coplanar structures than those obtained via QM methods, and the absolute MM energy values overestimate corresponding values ...

  20. Laser-based methods for the analysis of low molecular weight compounds in biological matrices.

    Science.gov (United States)

    Kiss, András; Hopfgartner, Gérard

    2016-07-15

    Laser-based desorption and/or ionization methods play an important role in the field of the analysis of low molecular-weight compounds (LMWCs) because they allow direct analysis with high-throughput capabilities. In the recent years there were several new improvements in ionization methods with the emergence of novel atmospheric ion sources such as laser ablation electrospray ionization or laser diode thermal desorption and atmospheric pressure chemical ionization and in sample preparation methods with the development of new matrix compounds for matrix-assisted laser desorption/ionization (MALDI). Also, the combination of ion mobility separation with laser-based ionization methods starts to gain popularity with access to commercial systems. These developments have been driven mainly by the emergence of new application fields such as MS imaging and non-chromatographic analytical approaches for quantification. This review aims to present these new developments in laser-based methods for the analysis of low-molecular weight compounds by MS and several potential applications. PMID:27107904

  1. Synthesis and electrical properties of fullerene-based molecular junctions on silicon substrate

    OpenAIRE

    GUERIN,D; Lenfant, S.; Godey, S.; Vuillaume, D.

    2010-01-01

    We report the synthesis and the electrical properties of fullerene-based molecular junctions on silicon substrate in which the highly \\pi-conjugated molecule C60 (\\pi quantum well) is isolated from the electrodes by alkyl chains (\\sigma tunnel barriers). Initially, the Si/SiO2/\\sigmaC60 architecture was prepared either by sequential synthesis (3 different routes) or by direct grafting of the presynthesized C60-\\sigma-Si(OEt)3 molecule. We described the chemical synthesis of these routes and t...

  2. Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents

    Directory of Open Access Journals (Sweden)

    Zhiguo Zhou

    2013-10-01

    Full Text Available Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging.

  3. Hydration of methanol in water. A DFT-based molecular dynamics study

    CERN Document Server

    Van Erp, T S; Erp, Titus S. van; Meijer, Evert Jan

    2000-01-01

    We studied the hydration of a single methanol molecule in aqueous solution by first-principle DFT-based molecular dynamics simulation. The calculations show that the local structural and short-time dynamical properties of the water molecules remain almost unchanged by the presence of the methanol, confirming the observation from recent experimental structural data for dilute solutions. We also see, in accordance with this experimental work, a distinct shell of water molecules that consists of about 15 molecules. We found no evidence for a strong tangential ordering of the water molecules in the first hydration shell.

  4. Carnitine tailored Sensors on Surface Molecular Imprinting based on Graphene layers

    OpenAIRE

    Truta, Liliana A.A.N.A.; Nádia S. Ferreira; M. Goreti F. Sales

    2013-01-01

    III Jornadas de Electroquímica e Inovação (Electroquímica e Nanomateriais), na Universidade de Trás-os-Montes e Alto Douro, Vila Real, 16 a 17 de Setembro de 2013 A new biosensor based on surface molecularly imprinted polymer (MIP) on graphene layers was successfully developed. It consists in a 3D polymeric network created on top of surface and around the target template, Carnitine (CRT), a potential biomarker of ovary cancer. The polymeric structure was obtained after radical polyme...

  5. Determination of phylogenetic position of Pipizini (Diptera: Syrphidae): based on molecular biological and morphological data

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the sequence analysis of 5.8S subunit and internal transcribed spacers (ITS ) of ribosomal RNA gene (rDNA), the molecular phylogenetic tree of representative species of Pipizini and three groups of Syrphidae with different feeding habits (seven species belong to six genera) was constructed. Meanwhile, the phylogenetic tree of tribes (including Pipizini and other 17 tribes of Syrphidae) was constructed using morphological characteristics of adults and larvae and the number of chromosomes. Both the results show that the relationship between Pipizini and predatory groups is closer than that between Pipizini and saprophagous groups. So it is suggested that Pipizini be transferred from Milesiinae to Syrphinae.

  6. Molecular Solid EOS based on Quasi-Harmonic Oscillator approximation for phonons

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-02

    A complete equation of state (EOS) for a molecular solid is derived utilizing a Helmholtz free energy. Assuming that the solid is nonconducting, phonon excitations dominate the specific heat. Phonons are approximated as independent quasi-harmonic oscillators with vibrational frequencies depending on the specific volume. The model is suitable for calibrating an EOS based on isothermal compression data and infrared/Raman spectroscopy data from high pressure measurements utilizing a diamond anvil cell. In contrast to a Mie-Gruneisen EOS developed for an atomic solid, the specific heat and Gruneisen coefficient depend on both density and temperature.

  7. Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

    Science.gov (United States)

    Sterckx, Hans; De Houwer, Johan; Mensch, Carl; Herrebout, Wouter; Tehrani, Kourosch Abbaspour

    2016-01-01

    Summary The methylene group of various substituted 2- and 4-benzylpyridines, benzyldiazines and benzyl(iso)quinolines was successfully oxidized to the corresponding benzylic ketones using a copper or iron catalyst and molecular oxygen as the stoichiometric oxidant. Application of the protocol in API synthesis is exemplified by the alternative synthesis of a precursor to the antimalarial drug Mefloquine. The oxidation method can also be used to prepare metabolites of APIs which is illustrated for the natural product papaverine. ICP–MS analysis of the purified reaction products revealed that the base metal impurity was well below the regulatory limit. PMID:26877817

  8. Nanoscale switch based on interacting molecular dipoles: Cooperativity can improve the device characteristics

    Science.gov (United States)

    Mafé, , Salvador; Manzanares, , José A.; Reiss, Howard

    2011-02-01

    We propose a nanoscale switch, giving a nonlinear function with two conductive states separated by a sharp transition region, on the basis of an array of molecular dipoles. We show theoretically that the local interactions between dipoles result in cooperative phenomena that can significantly improve the switching characteristics. We demonstrate the general validity of the concept in the cases of (i) an electrical switch robust to the finite size and variability effects inherent to the nanoscale and (ii) a sensing layer based on the voltage and ligand concentration dependence of the dipole array conductance.

  9. Theoretical study of the molecular bases that control photochemical processes with biological and nanotechnological interest

    OpenAIRE

    Saurí Peris, Vicenta

    2013-01-01

    El trabajo desarrollado en la tesis doctoral que lleva por título "Theoretical study of the molecular bases that control photochemical processes with biological and nanotechnological interest" se enmarca en las líneas de investigación del grupo QCEXVAL (Quantum Chemistry of the Excited State University of Valencia), que nació en el seno del departamento de Química Física de la Universitat de València en 1993. Se han abordado temas de interés metodológico, biológico y nanotecnológico. La prime...

  10. Sensors based on carbon nanotube field-effect transistors and molecular recognition approaches

    OpenAIRE

    Cid Salavert, Cristina Carlota

    2009-01-01

    La unión de las propiedades de los CNT con los principios de reconocimiento molecular se presenta como una base adecuada para el desarrollo de sensores altamente específicos. El objetivo de la presente tesis ha sido desarrollar sensores químicos, del tipo transistores de efecto campo (CNTFET), basados en interacciones receptor-analito, mediante el empleo de los nanotubos de pared sencilla (SWCNT), que actúan como transductores de la señal analítica.Las principales etapas de la parte experimen...

  11. Monitoring molecular orientational order in NLO push-pull based polymeric films via photoacoustic measurements

    Science.gov (United States)

    Torres-Zúñiga, V.; Castañeda-Guzmán, R.; Morales-Saavedra, O. G.; Pérez-Martínez, A. L.; Ogawa, T.

    2011-12-01

    The pulsed-laser photoacoustic-technique (PLPA) was implemented to characterize molecular orientational order and anisotropy in push-pull poled polymeric films as function of temperature and laser polarization. Traditionally, photoacoustic signals are considered to be directly proportional to the linear optical absorption in amorphous media. In this work, however, it is shown that photoacoustic signals can also be highly sensitive to the material anisotropy when convenient polarization dependent photoacoustic analyses are performed. Thus, variation of the molecular orientation in organic films, comprising rod-like polar chromophores, can be unambiguously monitored via rms-analyses performed on the amplitude of the generated opto-acoustical PLPA-signals as function of the incident laser polarization. This result can be useful for the characterization of organic-based nonlinear optical (NLO) poled films and, in general, in studies of anisotropic materials. In fact, in this work we were able to accurately determine the molecular order parameter ( ϕ) of a NLO-active spin-coated polymeric film containing optically active push-pull chromophores. These molecules, previously oriented via an electrical-poling procedure, are capable to exhibit strong second harmonic generation (SHG) effects. The PLPA-measurements were systematically compared to the linear UV-vis optical absorbance spectra while heating the poled film sample in order to monitor the thermally induced molecular disorder, so that the order parameter may be photo-acoustically evaluated via the PLPA-signals generated from the poled to the unpoled film phase. These PLPA-experiments were performed taking into account the UV-vis reference spectra for calibration and comparison purposes in the evaluation of the order parameter. A significant advantage of the PLPA-technique over commonly used optical spectral methodologies is its convenient applicability in samples exhibiting poor or null optical transmission.

  12. NACE: A web-based tool for prediction of intercompartmental efficiency of human molecular genetic networks.

    Science.gov (United States)

    Popik, Olga V; Ivanisenko, Timofey V; Saik, Olga V; Petrovskiy, Evgeny D; Lavrik, Inna N; Ivanisenko, Vladimir A

    2016-06-15

    Molecular genetic processes generally involve proteins from distinct intracellular localisations. Reactions that follow the same process are distributed among various compartments within the cell. In this regard, the reaction rate and the efficiency of biological processes can depend on the subcellular localisation of proteins. Previously, the authors proposed a method of evaluating the efficiency of biological processes based on the analysis of the distribution of protein subcellular localisation (Popik et al., 2014). Here, NACE is presented, which is an open access web-oriented program that implements this method and allows the user to evaluate the intercompartmental efficiency of human molecular genetic networks. The method has been extended by a new feature that provides the evaluation of the tissue-specific efficiency of networks for more than 2800 anatomical structures. Such assessments are important in cases when molecular genetic pathways in different tissues proceed with the participation of various proteins with a number of intracellular localisations. For example, an analysis of KEGG pathways, conducted using the developed program, showed that the efficiencies of many KEGG pathways are tissue-specific. Analysis of efficiencies of regulatory pathways in the liver, linking proteins of the hepatitis C virus with human proteins involved in the KEGG apoptosis pathway, showed that intercompartmental efficiency might play an important role in host-pathogen interactions. Thus, the developed tool can be useful in the study of the effectiveness of functioning of various molecular genetic networks, including metabolic, regulatory, host-pathogen interactions and others taking into account tissue-specific gene expression. The tool is available via the following link: http://www-bionet.sscc.ru/nace/. PMID:27109913

  13. Molecular phylogeny of Edraianthus (Grassy Bells; Campanulaceae) based on non-coding plastid DNA sequences

    DEFF Research Database (Denmark)

    Stefanovic, Sasa; Lakusic, Dmitar; Kuzmina, Maria; Mededovic, Safer; Tan, Kit; Stevanovic, Vladimir

    2008-01-01

    taxonomical standings are reevaluated based on molecular evidence. Our study identified several distinct monophyletic groups within Edraianthus, some of which correspond closely to previously established taxonomic treatments and some of which are first identified here. Morphologic, taxonomic, and...

  14. A fast-moving copper-based molecular shuttle: synthesis and dynamic properties.

    Science.gov (United States)

    Durola, Fabien; Lux, Jacques; Sauvage, Jean-Pierre

    2009-01-01

    Fast-track changes: The synthesis of a new copper-based molecular shuttle is described, with a coordinating macrocycle based on a nonhindering but endocyclic ligand (see scheme), which makes the ligand exchange easier, and thus the motions of the ring along the thread faster.The present report deals with the synthesis of a two-station [2]rotaxane consisting of a dpbiiq-incorporating macrocycle (dpbiiq: 8,8'-diphenyl-3,3'-biisoquinoline) threaded by a coordinating fragment whose complexing units are a dpp and a terpy ligand (dpp: 2,9-diphenyl-1,10-phenanthroline; terpy: 2,2',6',2"-terpyridine). The [2]rotaxane was prepared in 11 steps from commercially available or easy-to-make molecules, without taking into account the preparation of the dpbiiq-containing 39-membered ring, which was available in our group. The ring-incorporated bidentate chelate is at the same time endocyclic and sterically nonhindering, which is a specific property of the dpbiiq-coordinating unit. This unique feature has a profound influence on the rate of the ring-and-copper translation motion between the two stations of the axle. Based on an analogous multistep strategy, a related molecular shuttle has also been prepared that contains exactly the same axle and stoppers as the first compound but whose threaded ring incorporates the sterically hindering dpp chelate. The translation motions of this other system are several orders of magnitude slower than the corresponding movements of the dpbiiq-based compound. The motion corresponding to the rearrangement of the unstable five-coordinate copper(I) form of the compounds is relatively fast for both shuttles; the half lifetime of the five-coordinate Cu(I) species being below 20 ms for the dpbiiq-containing system and below 1 s for the dpp-based molecule. The reverse motion corresponding to the rearrangement of the four-coordinate copper(II) complexes is much slower, especially for the dpp-based system. It is of the order of several hours for the dpp-based

  15. Iron-sulfur-based single molecular wires for enhancing charge transport in enzyme-based bioelectronic systems.

    Science.gov (United States)

    Mahadevan, Aishwarya; Fernando, Teshan; Fernando, Sandun

    2016-04-15

    When redox enzymes are wired to electrodes outside a living cell (ex vivo), their ability to produce a sufficiently powerful electrical current diminishes significantly due to the thermodynamic and kinetic limitations associated with the wiring systems. Therefore, we are yet to harness the full potential of redox enzymes for the development of self-powering bioelectronics devices (such as sensors and fuel cells). Interestingly, nature uses iron-sulfur complexes ([Fe-S]), to circumvent these issues in vivo. Yet, we have not been able to utilize [Fe-S]-based chains ex vivo, primarily due to their instability in aqueous media. Here, a simple technique to attach iron (II) sulfide (FeS) to a gold surface in ethanol media and then complete the attachment of the enzyme in aqueous media is reported. Cyclic voltammetry and spectroscopy techniques confirmed the concatenation of FeS and glycerol-dehydrogenase/nicotinamide-adenine-dinucleotide (GlDH-NAD(+)) apoenzyme-coenzyme molecular wiring system on the base gold electrode. The resultant FeS-based enzyme electrode reached an open circuit voltage closer to its standard potential under a wide range of glycerol concentrations (0.001-1M). When probed under constant potential conditions, the FeS-based electrode was able to amplify current by over 10 fold as compared to electrodes fabricated with the conventional pyrroloquinoline quinone-based composite molecular wiring system. These improvements in current/voltage responses open up a wide range of possibilities for fabricating self-powering, bio-electronic devices. PMID:26657591

  16. La experiencia de mediación familiar en Chile

    Directory of Open Access Journals (Sweden)

    Paula Correa Camus

    2014-08-01

    Full Text Available La incorporación de la mediación familiar como un trámite previo y obligatorio al proceso judicial ha generado una amplia discusión en la doctrina y en los operadores del sistema. Uno de los debates más interesantes es aquel que pretende determinar los efectos de la obligatoriedad tanto en los procesos mismos de mediación como en sus resultados. El objetivo de este trabajo es examinar las ventajas y desventajas que traen aparejadas las políticas públicas que incluyen la participación obligatoria en mediación y, en ese contexto, analizar la experiencia chilena en mediación familiar.

  17. Evaluación: conceptualización, experiencias, prospecciones

    OpenAIRE

    Gómez, Víctor Manuel; Restrepo Forero, Gabriel Adolfo; Bustamante Zamudio, Guillermo; Serrano Orjuela, Eduardo; Bogoya Maldonado, Daniel; García Oliveros, Gloria; Cárdenas Beltrán, Melba Libia; Hernández, Carlos Augusto; Cárdenas Salgado, Fidel Antonio; Sarmiento Parra, Fernando

    2003-01-01

    Este libro está apoyado en las memorias de cada jornada del seminario «Evaluación: conceptualización, experiencias, prospecciones», desarrollado en el año 2002. / Contenido. Preliminares; Capítulo 1 - El contexto social y los usos sociales de la evaluación; Capítulo 2 - La evaluación externa en las áreas de lenguaje, matemáticas, ciencias y lengua extranjera; Capítulo 3 - Evaluación de competencias y formación social: una recapitulación; Capítulo 4 - Aspectos complementarios a la discusión; C...

  18. Aprendizaje con robótica, algunas experiencias

    OpenAIRE

    Pedro Antonio López Ramírez; Hugo Andrade Sosa

    2013-01-01

    Este artículo presenta el análisis de experiencias, revisadas en diversos artículos, acerca de la implementación de la robótica en la educación, con el fin de obtener referentes pertinentes para la construcción de una propuesta para el aprendizaje de la robótica en la educación básica secundaria y media. Se consideran dos ámbitos de aplicación de la robótica en la educación: el primero es el aprendizaje de la robótica mediante la conceptualización de cada uno de los subsistemas de un robot pa...

  19. Apuntes sobre historia empresarial: Relatos de algunas experiencias

    Directory of Open Access Journals (Sweden)

    Elber Berdugo Cotera

    2003-10-01

    Full Text Available El presente articulo tiene como objetivo mostrar la importancia de la Historia Empresarial y la constitución de una línea de investigación para el entendimiento de la historia del país y la comprensión de las principales características de nuestros empresarios tanto en el ámbito regional como en el nacional. Se trata igualmente, de dar cuenta de los aspectos teóricos y metodológicos utilizados en la investigación sobre el estudio de caso de Servientrega y sus gestores, lo mismo que de los principales hallazgos encontrados en ella. Por último, señalar cómo ésta clase de experiencias pueden resultar enriquecedoras para aquellas personas que ejercen una función educativa empresarial o pretenden asumir como proyecto personal y familiar de vida ser empresarios.

  20. Asesoramiento en la universidad. Poniendo a trabajar la experiencia

    Directory of Open Access Journals (Sweden)

    Marita Sánchez Moreno

    2008-01-01

    Full Text Available La Universidad española se encuentra en un momento crítico y decisivo. Los retos y desafíos que afrontará en estos próximos años relacionados con la Convergencia Europea van a suponer necesariamente cambios conceptuales y estructurales importantes. Uno de los pilares fundamentales que sustenta este proceso de cambio radica en tomar conciencia de la importancia que supone prestar atención a los procesos de formación de los docentes universitarios, una actividad que tradicionalmente se ha relegado en nuestra universidad. Este artículo argumenta la conveniencia de incorporar procesos de asesoramiento en el contexto universitario de manera sistemática e institucionalizada, como herramienta para la formación de los docentes en este modelo nuevo de universidad, y en consecuencia, como ayuda hacia la mejora y al incremento de la calidad docente. Partimos de la idea de aprovechamiento de recursos humanos existentes en la propia Universidad. Por eso, planteamos la pertinencia de recuperar la experiencia de profesores veteranos en la institución para la puesta en marcha de estos procesos de asesoramiento universitarios, ya que estos profesores conocen bien la cultura institucional y dominan el contenido curricular del área disciplinar. El artículo analiza la figura de estos profesores denominados mentores desde la comprensión de rol como tal, las características que les son atribuidas, la formación requerida para el desempeño de las funciones de asesoramiento, las actividades encomendadas y las dificultades detectadas en el ejercicio del rol. Este análisis queda ilustrado por la experiencia de asesoramiento desarrollada en la Universidad de Sevilla.

  1. Phylogeny of genera Laminaria and Saccharina (Laminariales, Phaeophyceae) based on three molecular markers

    Institute of Scientific and Technical Information of China (English)

    CHI Shan; QIAN Hao; LI Tianyong; WANG Xumin; LIU Cui; REN Lei; TANG Xuexi; LIU Tao

    2014-01-01

    In the past two decades, many studies have focused on the classification within genus Laminaria, ultimately trying to divide it into two subgroups or genera:Laminaria and Saccharina. A significant debate still sur-rounds the question of its division, as the conflicting phylogenetic hypotheses that have resulted from the classification studies are based on different taxon sampling, molecular markers, or analysis methods. It is aimed at elucidate the molecular phylogeny within Laminaria and Saccharina. The nine species of Lami-nariales are sampled from northern Asia and Europe, and 23 new sequences in the nuclear, plastid, and mitochondrial genomes are determined to identify their taxonomic status. The phylogenetic analyses of 71 species are performed, including representatives from six of the seven families of the order Laminariales, based on three separate data sets. An evidence is provided to strongly support a clear split that maintains the two recognized genera, Laminaria and Saccharina, with Laminaria appearing to be the ancestor group. Further, analyses indicate that all taxa in Saccharina and Laminaria did not form a monophyletic lineage, instead Laminariaceae and Lessoniaceae grouped together interlacedly, and Costariaceae appeared as the sister taxon of the Lessoniaceae-Laminariaceae clade. In the phylogenetic analysis, mitochondrial c oxi-dase I (COI) sequences appeared to be the most credible molecular marker which was more befitting than nuclear encoded internal transcribed spacer (ITS) and plastid encoded rbcL for establishment of Laminari-ales systematics. It is the most comprehensive phylogeny of the order Laminariales, and contributes to an enhanced understanding and estimation of the phylogenetic relationships for the economically important seaweeds, Laminaria and Saccharina.

  2. Una experiencia de trabajo en grupo desde la atención temprana

    OpenAIRE

    Bello Rovira, M.; Juanet Juliá, M.; Mañosa Mas, M.; Morral Subira, M.; Ribera Vilella, T.

    2010-01-01

    Las autoras de este artículo, integrantes del Equipo de Atención Temprana del Centro de Recursos Educativos de la ONCE en Barcelona, resaltan la importancia del trabajo en grupo dentro del proceso asistencial, y presentan su experiencia con un grupo de madres y niños con discapacidad visual y deficiencias múltiples. Describen la metodología adoptada, así como la evolución de la experiencia y los objetivos alcanzados.

  3. A clinical-molecular update on azanucleoside-based therapy for the treatment of hematologic cancers.

    Science.gov (United States)

    Diesch, Jeannine; Zwick, Anabel; Garz, Anne-Kathrin; Palau, Anna; Buschbeck, Marcus; Götze, Katharina S

    2016-01-01

    The azanucleosides azacitidine and decitabine are currently used for the treatment of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) in patients not only eligible for intensive chemotherapy but are also being explored in other hematologic and solid cancers. Based on their capacity to interfere with the DNA methylation machinery, these drugs are also referred to as hypomethylating agents (HMAs). As DNA methylation contributes to epigenetic regulation, azanucleosides are further considered to be among the first true "epigenetic drugs" that have reached clinical application. However, intriguing new evidence suggests that DNA hypomethylation is not the only mechanism of action for these drugs. This review summarizes the experience from more than 10 years of clinical practice with azanucleosides and discusses their molecular actions, including several not related to DNA methylation. A particular focus is placed on possible causes of primary and acquired resistances to azanucleoside treatment. We highlight current limitations for the success and durability of azanucleoside-based therapy and illustrate that a better understanding of the molecular determinants of drug response holds great potential to overcome resistance. PMID:27330573

  4. On the optimal design of molecular sensing interfaces with lipid bilayer assemblies - A knowledge based approach

    Science.gov (United States)

    Siontorou, Christina G.

    2012-12-01

    Biosensors are analytic devices that incorporate a biochemical recognition system (biological, biologicalderived or biomimic: enzyme, antibody, DNA, receptor, etc.) in close contact with a physicochemical transducer (electrochemical, optical, piezoelectric, conductimetric, etc.) that converts the biochemical information, produced by the specific biological recognition reaction (analyte-biomolecule binding), into a chemical or physical output signal, related to the concentration of the analyte in the measuring sample. The biosensing concept is based on natural chemoreception mechanisms, which are feasible over/within/by means of a biological membrane, i.e., a structured lipid bilayer, incorporating or attached to proteinaceous moieties that regulate molecular recognition events which trigger ion flux changes (facilitated or passive) through the bilayer. The creation of functional structures that are similar to natural signal transduction systems, correlating and interrelating compatibly and successfully the physicochemical transducer with the lipid film that is self-assembled on its surface while embedding the reconstituted biological recognition system, and at the same time manage to satisfy the basic conditions for measuring device development (simplicity, easy handling, ease of fabrication) is far from trivial. The aim of the present work is to present a methodological framework for designing such molecular sensing interfaces, functioning within a knowledge-based system built on an ontological platform for supplying sub-systems options, compatibilities, and optimization parameters.

  5. Hydrazone based molecular glasses for solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Biscarbazole and terthiophene based molecular glasses with hydrazone functional goups (named respectively 2CzMPH and 3TDPH) have been synthesized and the thermal, optical and electrochemical properties have been studied. Differential scanning calorimetry characterizations confirm the metastable amorphous properties of these molecules with glass transition temperatures at 80 deg. C for the 3TDPH and 93 deg. C for the 2CzMPH. Their electrochemical properties have been studied and showed the effect of the conjugated hydrazone groups on the electronic delocalization of the structures. The concept of solid state dye-sensitized solar cells using hydrazone based molecular glasses has been verified with the elaboration of a SnO2: F/nc-TiO2/Ru-dye/2CzMPH /Au devices. Under full sunlight (98 mW/cm2, air mass 1.5) the I-V characterization of the device give a short circuit photocurrents Isc = 0.42 mA/cm2, open circuit voltage Voc = 500 mV with a fill factor of 0.35

  6. Lipid-based nanocarrier for quercetin delivery: system characterization and molecular interactions studies.

    Science.gov (United States)

    Hädrich, Gabriela; Monteiro, Samantha Oliveira; Rodrigues, Marisa Raquel; de Lima, Vânia Rodrigues; Putaux, Jean-Luc; Bidone, Juliana; Teixeira, Helder Ferreira; Muccillo-Baisch, Ana Luiza; Dora, Cristiana Lima

    2016-07-01

    The flavonoid quercetin (QU) is a naturally occurring compound with several biological activities. However, the oral bioavailability of this compound is very low due to the high pre-systemic metabolism in the colon and liver and its low water solubility. In this context, the development of QU-loaded nanocarriers (NEs) is a promising approach to improve the drug oral bioavailability. This study investigates the variation of the concentration of 12-hydroxystearic acid-polyethylene glycol copolymer, lecithin and castor oil (CO) as to increase the amount of QU encapsulated while maintaining physicochemical characteristics described in previous studies. To better understand the ability to load and release the drug, we investigated the molecular interactions between QU and NE. Lipid-based NEs were prepared using CO as oily phase and PEG 660-stearate and lecithin as surfactants. Hot solvent diffusion and phase inversion temperature were methods employed to produce NEs. The QU-NEs were investigated for physicochemical characteristics and in vitro drug release. Molecular interactions between QU and the NEs were monitored through the complementary infrared (Fourier transform infrared) and NMR. The results revealed that it was possible to incorporate higher amounts of QU in a lipid-based NE with a reduced size (20 nm). The system developed allow a sustained release of QU probably due to the shell formed by the surfactants around the NE and the flavonoid ordering effect in the emulsion hydrophobic regions, which may reduce the system permeability. PMID:26571009

  7. Molecular beacon-based enzyme-free strategy for amplified DNA detection.

    Science.gov (United States)

    Huang, Jiahao; Wu, Jueqi; Li, Zhigang

    2016-05-15

    We report an enzyme-free, sensitive strategy for DNA detections through fluorescence amplification. The sensing method employs molecular beacons (MBs) and two single-stranded helper DNA probes. In the presence of a DNA target, it binds and opens an MB. This triggers the hybridizations between the MB and helper probes, and consequently releases the DNA target, which becomes available to react with another MB and enhances the fluorescence emission of the MBs. The detection limit of the proposed strategy is 0.58 pM, which is about 3 orders of magnitude better than the conventional MB-based method. This method is also fast and exhibits good selectivity. It is superior to previous MB-based amplification approaches employing enzymes or nanomaterials. PMID:26774091

  8. Syntheses of Ferrocenyl Schiff Bases Using Molecular Sieves and AlCl3 as Catalysts

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to study the donor ability of ferrocenylimines as directing ortho metalation group(DMG) to lithium alkylide to prepare planar chiral ferrocene, a series of ferrocenyl schiff bases were synthesized by new methods using molecular sieves(0.4nm) and AlCl3 as catalysts. The reaction periods were reduced using these two catalysts in contrast with Al2O3, which was a traditional method used in the literature. In addition, as an important feature of these schiff bases, we found that they were unstable as oils in air or when filtrated through silica gel, but were stable as solids. The structures of the new compounds were confirmed by IR, 1H NMR and HRMS.

  9. The importance of the rotor in hydrazone-based molecular switches

    Directory of Open Access Journals (Sweden)

    Xin Su

    2012-06-01

    Full Text Available The pH-activated E/Z isomerization of a series of hydrazone-based systems having different functional groups as part of the rotor (R = COMe, CN, Me, H, was studied. The switching efficiency of these systems was compared to that of a hydrazone-based molecular switch (R = COOEt whose E/Z isomerization is fully reversible. It was found that the nature of the R group is critical for efficient switching to occur; the R group should be a moderate H-bond acceptor in order to (i provide enough driving force for the rotor to move upon protonation, and (ii stabilize the obtained Z configuration, to achieve full conversion.

  10. Functionality in Electrospun Nanofibrous Membranes Based on Fiber’s Size, Surface Area, and Molecular Orientation

    Directory of Open Access Journals (Sweden)

    Akihiko Tanioka

    2011-08-01

    Full Text Available Electrospinning is a versatile method for forming continuous thin fibers based on an electrohydrodynamic process. This method has the following advantages: (i the ability to produce thin fibers with diameters in the micrometer and nanometer ranges; (ii one-step forming of the two- or three-dimensional nanofiber network assemblies (nanofibrous membranes; and (iii applicability for a broad spectrum of molecules, such as synthetic and biological polymers and polymerless sol-gel systems. Electrospun nanofibrous membranes have received significant attention in terms of their practical applications. The major advantages of nanofibers or nanofibrous membranes are the functionalities based on their nanoscaled-size, highly specific surface area, and highly molecular orientation. These functionalities of the nanofibrous membranes can be controlled by their fiber diameter, surface chemistry and topology, and internal structure of the nanofibers. This report focuses on our studies and describes fundamental aspects and applications of electrospun nanofibrous membranes.

  11. Exploring Programmable Self-Assembly in Non-DNA based Molecular Computing

    CERN Document Server

    Terrazas, German; Krasnogor, Natalio

    2013-01-01

    Self-assembly is a phenomenon observed in nature at all scales where autonomous entities build complex structures, without external influences nor centralised master plan. Modelling such entities and programming correct interactions among them is crucial for controlling the manufacture of desired complex structures at the molecular and supramolecular scale. This work focuses on a programmability model for non DNA-based molecules and complex behaviour analysis of their self-assembled conformations. In particular, we look into modelling, programming and simulation of porphyrin molecules self-assembly and apply Kolgomorov complexity-based techniques to classify and assess simulation results in terms of information content. The analysis focuses on phase transition, clustering, variability and parameter discovery which as a whole pave the way to the notion of complex systems programmability.

  12. Kazusa Marker DataBase: a database for genomics, genetics, and molecular breeding in plants.

    Science.gov (United States)

    Shirasawa, Kenta; Isobe, Sachiko; Tabata, Satoshi; Hirakawa, Hideki

    2014-09-01

    In order to provide useful genomic information for agronomical plants, we have established a database, the Kazusa Marker DataBase (http://marker.kazusa.or.jp). This database includes information on DNA markers, e.g., SSR and SNP markers, genetic linkage maps, and physical maps, that were developed at the Kazusa DNA Research Institute. Keyword searches for the markers, sequence data used for marker development, and experimental conditions are also available through this database. Currently, 10 plant species have been targeted: tomato (Solanum lycopersicum), pepper (Capsicum annuum), strawberry (Fragaria × ananassa), radish (Raphanus sativus), Lotus japonicus, soybean (Glycine max), peanut (Arachis hypogaea), red clover (Trifolium pratense), white clover (Trifolium repens), and eucalyptus (Eucalyptus camaldulensis). In addition, the number of plant species registered in this database will be increased as our research progresses. The Kazusa Marker DataBase will be a useful tool for both basic and applied sciences, such as genomics, genetics, and molecular breeding in crops. PMID:25320561

  13. Remote stabilization of copper paddlewheel based molecular building blocks in metal-organic frameworks

    KAUST Repository

    Gao, Wenyang

    2015-03-24

    Copper paddlewheel based molecular building blocks (MBBs) are ubiquitous and have been widely employed for the construction of highly porous metal-organic frameworks (MOFs). However, most copper paddlewheel based MOFs fail to retain their structural integrity in the presence of water. This instability is directly correlated to the plausible displacement of coordinating carboxylates in the copper paddlewheel MBB, [Cu2(O2C-)4], by the strongly coordinating water molecules. In this comprehensive study, we illustrate the chemical stability control in the rht-MOF platform via strengthening the coordinating bonds within the triangular inorganic MBB, [Cu3O(N4-x(CH)xC-)3] (x = 0, 1, or 2). Remotely, the chemical stabilization propagated into the paddlewheel MBB to afford isoreticular rht-MOFs with remarkably enhanced water/chemical stabilities compared to the prototypal rht-MOF-1. © 2015 American Chemical Society.

  14. Labyrinthine water flow across multilayer graphene-based membranes: molecular dynamics versus continuum predictions

    CERN Document Server

    Yoshida, Hiroaki

    2016-01-01

    In this paper we investigate the hydrodynamic permeance of water through graphene-based membranes, inspired by recent experimental findings on graphene-oxide membranes. We consider the flow across multiple graphene layers having nanoslits in a staggered alignment, with an inter-layer distance ranging from sub- nanometer to a few nanometers. We compare results for the permeability obtained by means of molecular dynamics simulations to continuum predictions obtained by using the lattice Boltzmann calculations and hydrodynamic modelization. This highlights that, in spite of extreme confinement, the permeability across the graphene-based membrane is quantitatively predicted on the basis of a continuum expression, taking properly into account entrance and slippage effects of the confined water flow. Our predictions refute the breakdown of hydrodynamics at small scales in these membrane systems. They constitute a benchmark to which we compare published experimental data.

  15. Initiating Heavy-atom Based Phasing by Multi-Dimensional Molecular Replacement

    DEFF Research Database (Denmark)

    Pedersen, Bjørn Panyella; Gourdon, Pontus; Liu, Xiangyu;

    2014-01-01

    in the determination of a membrane protein structure, the CopA Cu+-ATPase, when other methods had failed to resolve the heavy atom substructure. MRPM is particularly suited for proteins undergoing large conformational changes where multiple search models should be generated, and it enables the identification of weak......To obtain an electron-density map from a macromolecular crystal the phase-problem needs to be solved, which often involves the use of heavy-atom derivative crystals and concomitantly the determination of the heavy atom substructure. This is customarily done by direct methods or Patterson......-based approaches, which however may fail when only poorly diffracting derivative crystals are available, as often the case for e.g. membrane proteins. Here we present an approach for heavy atom site identification based on a Molecular Replacement Parameter Matrix (MRPM) search. It involves an n-dimensional search...

  16. Remote Stabilization of Copper Paddlewheel Based Molecular Building Blocks in Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wen-Yang; Cai, Rong; Pham, Tony; Forrest, Katherine A.; Hogan, Adam; Nugent, Patrick; Williams, Kia; Wojtas, Lukasz; Luebke, Ryan; Weseli; #324; ski, Lukasz J.; Zaworotko, Michael J.; Space, Brian; Chen, Yu-Sheng; Eddaoudi, Mohamed; Shi, Xiaodong; Ma, Shengqian (KAUST); (UC); (USF); (WVU)

    2015-08-21

    Copper paddlewheel based molecular building blocks (MBBs) are ubiquitous and have been widely employed for the construction of highly porous metal–organic frameworks (MOFs). However, most copper paddlewheel based MOFs fail to retain their structural integrity in the presence of water. This instability is directly correlated to the plausible displacement of coordinating carboxylates in the copper paddlewheel MBB, [Cu₂(O₂C-)₄], by the strongly coordinating water molecules. In this comprehensive study, we illustrate the chemical stability control in the rht-MOF platform via strengthening the coordinating bonds within the triangular inorganic MBB, [Cu₃O(N4–x(CH)xC-)₃] (x = 0, 1, or 2). Remotely, the chemical stabilization propagated into the paddlewheel MBB to afford isoreticular rht-MOFs with remarkably enhanced water/chemical stabilities compared to the prototypal rht-MOF-1.

  17. Innovative molecular-based fluorescent nanoparticles for multicolor single particle tracking in cells

    Science.gov (United States)

    Daniel, Jonathan; Godin, Antoine G.; Palayret, Matthieu; Lounis, Brahim; Cognet, Laurent; Blanchard-Desce, Mireille

    2016-03-01

    Based on an original molecular-based design, we present bright and photostable fluorescent organic nanoparticles (FONs) showing excellent colloidal stability in various aqueous environments. Complementary near-infrared emitting and green emitting FONs were prepared using a simple, fast and robust protocol. Both types of FONs could be simultaneously imaged at the single-particle level in solution as well as in biological environments using a monochromatic excitation and a dual-color fluorescence microscope. No evidence of acute cytotoxicity was found upon incubation of live cells with mixed solutions of FONs, and both types of nanoparticles were found internalized in the cells where their motion could be simultaneously tracked at video-rate up to minutes. These fluorescent organic nanoparticles open a novel non-toxic alternative to existing nanoparticles for imaging biological structures, compatible with live-cell experiments and specially fitted for multicolor single particle tracking.

  18. Molecular thermodynamic modeling of ionic liquids using the perturbation-based linear Yukawa isotherm regularity.

    Science.gov (United States)

    Sohrabi Mahboub, Mahdi; Farrokhpour, Hossein

    2016-06-15

    In this paper, we present the results of an extensive study on a novel approach to the molecular modeling of pure ionic liquids (ILs) that incorporates the perturbed thermodynamic linear Yukawa isotherm regularity (LYIR), which is derived based on an effective nearest neighboring pair attractive interaction of the Yukawa potential. The LYIR was used to model the densities of ILs up to high pressures (35 MPa) and in the temperature range 293.15 to 393.15 K. To use the LYIR for ILs, a simple molecular model was proposed to describe their molecular structure, in which they were considered as a liquid consisting of the ion pairs moving together in the fluid, and each ion pair was assumed to be a one-center spherical united atom. The ILs under consideration contained one of the IL cations [C2mim](+), [C4mim](+), [C7mim](+), [C8mim](+), [C3mpy](+), [C3mpip](+), [C3mpyr](+) or [C4mpyr](+), and one of the IL anions [BF4](-), [C(CN)3](-), [CF3SO4](-) or [NTf2](-). The reliability and physical significance of the parameters as well as the proposed molecular model were tested by calculating the densities of pure imidazolium-, pyridinium-, piperidinium- and pyrrolidimium-based ILs. The results showed that the LYIR can be used to predict and reproduce the density of ILs in good agreement with the experimental data. In addition, the LYIR enabled us to determine the physical quantities, such as an effective Yukawa screening length, λ eff, the product of the effective energy well depth and the effective coordination number, (ε eff/k)z eff, the contribution of the non-reference thermal pressure and also the influence of the anionic and cationic structure on the λ eff parameter. The standard deviation of the IL densities predicted in this work is lower than those calculated by the one other important equation of state reported in the literature. PMID:27157142

  19. Molecular thermodynamic modeling of ionic liquids using the perturbation-based linear Yukawa isotherm regularity

    Science.gov (United States)

    Sohrabi Mahboub, Mahdi; Farrokhpour, Hossein

    2016-06-01

    In this paper, we present the results of an extensive study on a novel approach to the molecular modeling of pure ionic liquids (ILs) that incorporates the perturbed thermodynamic linear Yukawa isotherm regularity (LYIR), which is derived based on an effective nearest neighboring pair attractive interaction of the Yukawa potential. The LYIR was used to model the densities of ILs up to high pressures (35 MPa) and in the temperature range 293.15 to 393.15 K. To use the LYIR for ILs, a simple molecular model was proposed to describe their molecular structure, in which they were considered as a liquid consisting of the ion pairs moving together in the fluid, and each ion pair was assumed to be a one-center spherical united atom. The ILs under consideration contained one of the IL cations [C2mim]+, [C4mim]+, [C7mim]+, [C8mim]+, [C3mpy]+, [C3mpip]+, [C3mpyr]+ or [C4mpyr]+, and one of the IL anions [BF4]‑, [C(CN)3]‑, [CF3SO4]‑ or [NTf2]‑. The reliability and physical significance of the parameters as well as the proposed molecular model were tested by calculating the densities of pure imidazolium-, pyridinium-, piperidinium- and pyrrolidimium-based ILs. The results showed that the LYIR can be used to predict and reproduce the density of ILs in good agreement with the experimental data. In addition, the LYIR enabled us to determine the physical quantities, such as an effective Yukawa screening length, λ eff, the product of the effective energy well depth and the effective coordination number, (ε eff/k)z eff, the contribution of the non-reference thermal pressure and also the influence of the anionic and cationic structure on the λ eff parameter. The standard deviation of the IL densities predicted in this work is lower than those calculated by the one other important equation of state reported in the literature.

  20. La formación de posgrado en Epidemiología: estrategias pedagógicas de una experiencia

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    Ana Cecília Augsburger

    2007-04-01

    Full Text Available El artículo describe y analiza la experiencia de elaboración e implementación de un proyecto educativo destinado a formar profesionales de la salud en el área epidemiológica. Con el propósito de profundizar la reflexión en torno a las diferentes estrategias pedagógicas adoptadas y, en particular valorar las posibilidades de innovación que la pedagogía crítica permite, se analiza la experiencia de enseñanza-aprendizaje vinculada al desarrollo de trabajos de campo en la formación de especialistas en Epidemiología. En primer lugar se aborda el contexto socio-sanitario en el cual se diseña e implementa la carrera de Epidemiología en la Universidad Nacional de Rosario (Argentina. Luego se profundiza en las posibilidades de integración entre prácticas educativas e intervenciones sanitarias a través de la elaboración del plan curricular; para finalmente examinar la estrategia pedagógica adoptada. Se concluye identificando algunos de los desafíos que se presentan con base en la evaluación educativa realizada.

  1. Neoliberalismo, corporativismo y experiencias posicionales: Los casos de Chile y Francia Neoliberalism, corporatism and positional experiences: The cases of Chile and France

    Directory of Open Access Journals (Sweden)

    Catalina Arteaga A.

    2012-06-01

    Full Text Available Apoyándose en un conjunto de investigaciones cualitativas, el artículo propone una comparación de las experiencias posicionales en las sociedades chilena y francesa. Sin descuidar las diferencias que se observan a este respecto entre los grupos sociales en cada uno de los países estudiados, el artículo se interesa sobre todo en los disímiles perfiles nacionales de estas experiencias. Se diseñan, así, claramente, dos modelos de experiencia posicional, a través de la articulación de modelos sociales de estratificación, naturaleza de las consistencias posicionales, conductas individuales y malestares subjetivos.Based on a set of qualitative research, the article proposes a comparison of positional experience in Chilean and French societies. Without neglecting the observable differences between social groups within each of the countries studied, the article is primarily concerned with the different national profiles of these experiences. Two models of positional experience are clearly designed by articulating social stratification patterns, nature of positional consistencies, individual behavior and subjective discomfort.

  2. Molecular similarity-based predictions of the Tox21 screening outcome

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    Malgorzata Natalia Drwal

    2015-07-01

    Full Text Available To assess the toxicity of new chemicals and drugs, regulatory agencies require in vivo testing for many toxic endpoints, resulting in millions of animal experiments conducted each year. However, following the Replace, Reduce, Refine (3R principle, the development and optimization of alternative methods, in particular in silico methods, has been put into focus in the recent years. It is generally acknowledged that the more complex a toxic endpoint, the more difficult it is to model. Therefore, computational toxicology is shifting from modelling general and complex endpoints to the investigation and modelling of pathways of toxicity and the underlying molecular effects.The U.S. Toxicology in the 21st Century (Tox21 initiative has screened a large library of compounds, including approximately 10K environmental chemicals and drugs, for different mechanisms responsible for eliciting toxic effects, and made the results publicly available. Through the Tox21 Data Challenge, the consortium has established a platform for computational toxicologists to develop and validate their predictive models.Here, we present a fast and successful method for the prediction of different outcomes of the nuclear receptor and stress response pathway screening from the Tox21 Data Challenge 2014. The method is based on the combination of molecular similarity calculations and a naïve Bayes machine learning algorithm and has been implemented as a KNIME pipeline. Molecules are represented as binary vectors consisting of a concatenation of common two-dimensional molecular fingerprint types with topological compound properties. The prediction method has been optimized individually for each modelled target and evaluated in a cross-validation as well as with the independent Tox21 validation set. Our results show that the method can achieve good prediction accuracies and rank among the top algorithms submitted to the prediction challenge, indicating its broad applicability in

  3. Cyndi: a multi-objective evolution algorithm based method for bioactive molecular conformational generation

    Directory of Open Access Journals (Sweden)

    Li Honglin

    2009-03-01

    Full Text Available Abstract Background Conformation generation is a ubiquitous problem in molecule modelling. Many applications require sampling the broad molecular conformational space or perceiving the bioactive conformers to ensure success. Numerous in silico methods have been proposed in an attempt to resolve the problem, ranging from deterministic to non-deterministic and systemic to stochastic ones. In this work, we described an efficient conformation sampling method named Cyndi, which is based on multi-objective evolution algorithm. Results The conformational perturbation is subjected to evolutionary operation on the genome encoded with dihedral torsions. Various objectives are designated to render the generated Pareto optimal conformers to be energy-favoured as well as evenly scattered across the conformational space. An optional objective concerning the degree of molecular extension is added to achieve geometrically extended or compact conformations which have been observed to impact the molecular bioactivity (J Comput -Aided Mol Des 2002, 16: 105–112. Testing the performance of Cyndi against a test set consisting of 329 small molecules reveals an average minimum RMSD of 0.864 Å to corresponding bioactive conformations, indicating Cyndi is highly competitive against other conformation generation methods. Meanwhile, the high-speed performance (0.49 ± 0.18 seconds per molecule renders Cyndi to be a practical toolkit for conformational database preparation and facilitates subsequent pharmacophore mapping or rigid docking. The copy of precompiled executable of Cyndi and the test set molecules in mol2 format are accessible in Additional file 1. Conclusion On the basis of MOEA algorithm, we present a new, highly efficient conformation generation method, Cyndi, and report the results of validation and performance studies comparing with other four methods. The results reveal that Cyndi is capable of generating geometrically diverse conformers and outperforms

  4. Potentiometric Sensors Based on Surface Molecular Imprinting: Detection of Cancer Biomarkers and Viruses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Zhang, Z; Jain, V; Yi, J; Mueller, S; Sokolov, J; Liu, Z; Levon, K; Rigas, B; Rafailovich, M

    2010-01-01

    The continuing discovery of cancer biomarkers necessitates improved methods for their detection. Molecular imprinting using artificial materials provides an alternative to the detection of a wide range of substances. We applied surface molecular imprinting using self-assembled monolayers to design sensing elements for the detection of cancer biomarkers and other proteins. These elements consist of a gold-coated silicon chip onto which hydroxyl-terminated alkanethiol molecules and template biomolecule are co-adsorbed, where the thiol molecules are chemically bound to the metal substrate and self-assembled into highly ordered monolayers, the biomolecules can be removed, creating the foot-print cavities in the monolayer matrix for this kind of template molecules. Re-adsorption of the biomolecules to the sensing chip changes its potential, which can be measured potentiometrically. We applied this method to the detection of carcinoembryonic antigen (CEA) in both solutions of purified CEA and in the culture medium of a CEA-producing human colon cancer cell line. The CEA assay, validated also against a standard immunoassay, was both sensitive (detection range 2.5-250 ng/mL) and specific (no cross-reactivity with hemoglobin; no response by a non-imprinted sensor). Similar results were obtained for human amylase. In addition, we detected virions of poliovirus in a specific manner (no cross-reactivity to adenovirus, no response by a non-imprinted sensor). Our findings demonstrate the application of the principles of molecular imprinting to the development of a new method for the detection of protein cancer biomarkers and to protein-based macromolecular structures such as the capsid of a virion. This approach has the potential of generating a general assay methodology that could be highly sensitive, specific, simple and likely inexpensive.

  5. Molecular and cell-based therapies for muscle degenerations: a road under construction

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    Maurilio eSampaolesi

    2014-04-01

    Full Text Available There are no specific treatments for muscular degeneration caused by muscular dystrophies and for muscle wasting caused by cachexia or sarcopenia. Corticosteroid medications for dystrophic patients only helps to control inflammatory process and slightly delay the progression of the disease. Walkers and wheel chairs are the only options to maintain patients’ independence and walking capabilities until respiratory muscles become weak and mechanical ventilation is mandatory. On the other hand myostatin inhibition, melanocortin-4 receptor antagonists, β-blockers, IL-6 antagonism, and synthetic ghrelin are promising treatments for cachectic animal models. Although in both cases muscular degeneration is relevant the translational therapeutic attempts to find a possible cure are well defined. Molecular treatments are common options to explore beneficial treatments for cachexia, and gene/cell therapies are mostly employed to induce the phenotypic improvement of dystrophic muscles. This review deals with the use of molecular administrations and gene/stem cell therapy to treat muscular degenerations. It reviews previous trials using cell delivery protocols in mice and patients starting with the use of donor myoblasts, outlining the likely causes for their poor results and briefly focusing on satellite cell studies that raise new hope. Then it proceeds to describe recently identified stem/progenitor cells in relationship to their ability to home within a dystrophic muscle and to differentiate into skeletal muscle cells. Different known features of various stem cells are compared in this perspective, and the few available examples of their use in animal models of muscular degeneration are reported. This review also provides an outline of the role of microRNAs to control myogenic commitment. Finally, based on our current knowledge and the rapid advance in stem cell biology a prediction of clinical translation for cell therapy protocols combined with

  6. Photorefractive effect in triphenylamine-based monolithic molecular glasses with low Tg

    International Nuclear Information System (INIS)

    Research highlights: → A series of triphenylamine-based molecular glasses with low Tg and long-term stability were designed and prepared via simple reactions. → Single-component M1 exhibited the better PR performance with a gain coefficient of 52 cm-1 (0 V μm-1) and 165 cm-1 (40 V μm-1). Fast response time of 0.025-0.23 s were obtained at low electric field for these glasses. → The overall performances suggest that the present triphenylamine-based molecules are potentially good candidates for commercial application in organic photorefractive devices. - Abstract: A novel series of triphenylamine-based photorefractive molecules M1-M5 with the different push-pull structures were designed and prepared. These molecules can form stable glasses with low glass transition temperature and their optical absorptions as well as photoconductivities at 633 nm increase systematically with increasing acceptor strength and conjugation length. As an unambiguous evidence, the two-beam-coupling experiment was performed to prove the photorefractive effect in each compound with or without an additional sensitizer. Obvious two-beam-coupling effects were obtained for the molecules with good film-forming ability and long-term stability, and among them single-component M1 which has a highly asymmetric structure using both a nitrobenzene and a cyano group as the acceptor showed the best PR performance with a gain coefficient of 52 cm-1 at 0 V μm-1 and 165 cm-1 at 40 V μm-1. Fast response time of 0.025-0.23 s were also obtained at low electric field for these glasses. The correlation of the molecular structure with the PR property was discussed, and a possible explanation for the unique energy transfer observed in M1 and M2 under zero field was proposed.

  7. Ecotope-Based Entomological Surveillance and Molecular Xenomonitoring of Multidrug Resistant Malaria Parasites in Anopheles Vectors

    Directory of Open Access Journals (Sweden)

    Prapa Sorosjinda-Nunthawarasilp

    2014-01-01

    Full Text Available The emergence and spread of multidrug resistant (MDR malaria caused by Plasmodium falciparum or Plasmodium vivax have become increasingly important in the Greater Mekong Subregion (GMS. MDR malaria is the heritable and hypermutable property of human malarial parasite populations that can decrease in vitro and in vivo susceptibility to proven antimalarial drugs as they exhibit dose-dependent drug resistance and delayed parasite clearance time in treated patients. MDR malaria risk situations reflect consequences of the national policy and strategy as this influences the ongoing national-level or subnational-level implementation of malaria control strategies in endemic GMS countries. Based on our experience along with current literature review, the design of ecotope-based entomological surveillance (EES and molecular xenomonitoring of MDR falciparum and vivax malaria parasites in Anopheles vectors is proposed to monitor infection pockets in transmission control areas of forest and forest fringe-related malaria, so as to bridge malaria landscape ecology (ecotope and ecotone and epidemiology. Malaria ecotope and ecotone are confined to a malaria transmission area geographically associated with the infestation of Anopheles vectors and particular environments to which human activities are related. This enables the EES to encompass mosquito collection and identification, salivary gland DNA extraction, Plasmodium- and species-specific identification, molecular marker-based PCR detection methods for putative drug resistance genes, and data management. The EES establishes strong evidence of Anopheles vectors carrying MDR P. vivax in infection pockets epidemiologically linked with other data obtained during which a course of follow-up treatment of the notified P. vivax patients receiving the first-line treatment was conducted. For regional and global perspectives, the EES would augment the epidemiological surveillance and monitoring of MDR falciparum and

  8. Synchrotron-Based Microspectroscopic Analysis of Molecular and Biopolymer Structures Using Multivariate Techniques and Advanced Multi-Components Modeling

    International Nuclear Information System (INIS)

    More recently, advanced synchrotron radiation-based bioanalytical technique (SRFTIRM) has been applied as a novel non-invasive analysis tool to study molecular, functional group and biopolymer chemistry, nutrient make-up and structural conformation in biomaterials. This novel synchrotron technique, taking advantage of bright synchrotron light (which is million times brighter than sunlight), is capable of exploring the biomaterials at molecular and cellular levels. However, with the synchrotron RFTIRM technique, a large number of molecular spectral data are usually collected. The objective of this article was to illustrate how to use two multivariate statistical techniques: (1) agglomerative hierarchical cluster analysis (AHCA) and (2) principal component analysis (PCA) and two advanced multicomponent modeling methods: (1) Gaussian and (2) Lorentzian multi-component peak modeling for molecular spectrum analysis of bio-tissues. The studies indicated that the two multivariate analyses (AHCA, PCA) are able to create molecular spectral corrections by including not just one intensity or frequency point of a molecular spectrum, but by utilizing the entire spectral information. Gaussian and Lorentzian modeling techniques are able to quantify spectral omponent peaks of molecular structure, functional group and biopolymer. By application of these four statistical methods of the multivariate techniques and Gaussian and Lorentzian modeling, inherent molecular structures, functional group and biopolymer onformation between and among biological samples can be quantified, discriminated and classified with great efficiency.

  9. Anisotropy induced Kondo splitting in a mechanically stretched molecular junction: A first-principles based study

    International Nuclear Information System (INIS)

    The magnetic anisotropy and Kondo phenomena in a mechanically stretched magnetic molecular junction are investigated by combining the density functional theory (DFT) and hierarchical equations of motion (HEOM) approach. The system is comprised of a magnetic complex Co(tpy–SH)2 sandwiched between adjacent gold electrodes, which is mechanically stretched in experiments done by Parks et al. [Science 328, 1370 (2010)]. The electronic structure and mechanical property of the stretched system are investigated via the DFT calculations. The HEOM approach is then employed to characterize the Kondo resonance features, based on the Anderson impurity model parameterized from the DFT results. It is confirmed that the ground state prefers the S = 1 local spin state. The structural properties, the magnetic anisotropy, and corresponding Kondo peak splitting in the axial stretching process are systematically evaluated. The results reveal that the strong electron correlations and the local magnetic properties of the molecule magnet are very sensitive to structural distortion. This work demonstrates that the combined DFT+HEOM approach could be useful in understanding and designing mechanically controlled molecular junctions

  10. Molecular-Based Theory for Electron-Transfer Reorganization Energy in Solvent Mixtures.

    Science.gov (United States)

    Zhuang, Bilin; Wang, Zhen-Gang

    2016-07-01

    Using statistical-field techniques, we develop a molecular-based dipolar self-consistent-field theory (DSCFT) for charge solvation in liquid mixtures under equilibrium and nonequilibrium conditions, and apply it to compute the solvent reorganization energy of electron-transfer reactions. In addition to the nonequilibrium orientational polarization, the reorganization energy in liquid mixtures is also determined by the out-of-equilibrium solvent composition around the reacting species due to preferential solvation. Using molecular parameters that are readily available, the DSCFT naturally accounts for the dielectric saturation effect and the spatially varying solvent composition in the vicinity of the reacting species. We identify three general categories of binary solvent mixtures, classified by the relative optical and static dielectric permittivities of the solvent components. Each category of mixture is shown to produce a characteristic local solvent composition profile in the vicinity of the reacting species, which gives rise to the distinctive composition dependence of the reorganization energy that cannot be predicted using the dielectric permittivities of the homogeneous solvent mixtures. PMID:27187110

  11. Inquiry-Based Learning: Inflammation as a Model to Teach Molecular Techniques for Assessing Gene Expression

    Directory of Open Access Journals (Sweden)

    Kathryn E. Gunn

    2013-08-01

    Full Text Available This laboratory module simulates the process used by working scientists to ask and answer a question of biological interest. Instructors facilitate acquisition of knowledge using a comprehensive, inquiry-based approach in which students learn theory, hypothesis development, experimental design, and data interpretation and presentation. Using inflammation in macrophages as a model system, students perform a series of molecular biology techniques to address the biological question: “Does stimulus ‘X’ induce inflammation?” To ask this question, macrophage cells are treated with putative inflammatory mediators and then assayed for evidence of inflammatory response. Students become familiar with their assigned mediator and the relationship between their mediator and inflammation by conducting literature searches, then using this information to generate hypotheses which address the effect of their mediator on induction of inflammation. The cellular and molecular approaches used to test their hypotheses include transfection and luciferase reporter assay, immunoblot, fluorescence microscopy, enzyme-linked immunosorbent assay, and quantitative PCR. Quantitative and qualitative reasoning skills are developed through data analysis and demonstrated by successful completion of post-lab worksheets and the generation and oral presentation of a scientific poster. Learning objective assessment relies on four instruments: pre-lab quizzes, post-lab worksheets, poster presentation, and posttest. Within three cohorts (n = 85 more than 95% of our students successfully achieved the learning objectives.

  12. Prediction of transport properties of new functional lanthanum-strontium cuprates based materials: molecular dynamics calculations

    International Nuclear Information System (INIS)

    Molecular dynamics method is used for the properties prediction of new lanthanum-strontium cuprates La2-xSrxCuO4-δ based functional materials. The most interesting phases have been synthesized, and electrophysical and thermomechanical properties have been investigated for the verification of acquired calculated data. High values of oxygen diffusion constants is demonstrated to be occurred in solid solutions La2-xSrxCuO4-δ with fine degree of substitution Sr→La (to x=1). Values of lattice parameters, thermal expansion coefficients and oxygen diffusion constants are agree with experimental data. Observed anisotropy of anion transport for all studied compositions is responsible for peculiarities of crystal structure of complex oxides. Applied molecular dynamics method permits to reveal the contribution of separate kinds of oxygen ions (equatorial and apical) in ionic transport at microscopic level, as well as really prove that the oxygen diffusion happens in the ordinary jump mechanism, mainly in (CuO2)-layers

  13. The effects of zeolite molecular sieve based surface treatments on the properties of wool fabrics

    Science.gov (United States)

    Carran, Richard S.; Ghosh, Arun; Dyer, Jolon M.

    2013-12-01

    Wool is a natural composite fiber, with keratin and keratin-associated proteins as the key molecular components. The outermost surface of wool fibers comprises a hydrophobic lipid layer that can lead to unsatisfactory processing and properties of fabric products. In this study, molecular sieve 5A, a Na+ and Ca2+ exchanged type A zeolite with a 1:1 Si:Al ratio was integrated onto the surface of wool using 3-mercaptopropyl trimethoxy silane. The resultant surface morphology, hydrophilicity and mechanical performance of the treated wool fabrics were then evaluated. Notably, the surface hydrophilicity of wool was observed to increase dramatically. When wool was treated with a dispersion of 2 wt% acetic acid, 2.5 wt% zeolite and 0.3 wt% or more silane, the water contact angle was observed to decrease from an average value of 148° to 0° over a period of approximately 30 s. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, with infrared spectroscopic evaluation indicating strong bonding of the dealuminated zeolite to wool keratins. This application of zeolite showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite-based treatment is a potentially efficient approach to increasing the surface hydrophilicity and modifying other key surface properties of wool and wool fabrics.

  14. Probing flexibility in porphyrin-based molecular wires using double electron electron resonance.

    Science.gov (United States)

    Lovett, Janet E; Hoffmann, Markus; Cnossen, Arjen; Shutter, Alexander T J; Hogben, Hannah J; Warren, John E; Pascu, Sofia I; Kay, Christopher W M; Timmel, Christiane R; Anderson, Harry L

    2009-09-30

    A series of butadiyne-linked zinc porphyrin oligomers, with one, two, three, and four porphyrin units and lengths of up to 75 A, have been spin-labeled at both ends with stable nitroxide TEMPO radicals. The pulsed EPR technique of double electron electron resonance (DEER) was used to probe the distribution of intramolecular end-to-end distances, under a range of conditions. DEER measurements were carried out at 50 K in two types of dilute solution glasses: deutero-toluene (with 10% deutero-pyridine) and deutero-o-terphenyl (with 5% 4-benzyl pyridine). The complexes of the porphyrin oligomers with monodentate ligands (pyridine or 4-benzyl pyridine) principally adopt linear conformations. Nonlinear conformations are less populated in the lower glass-transition temperature solvent. When the oligomers bind star-shaped multidentate ligands, they are forced to bend into nonlinear geometries, and the experimental end-to-end distances for these complexes match those from molecular mechanics calculations. Our results show that porphyrin-based molecular wires are shape-persistent, and yet that their shapes can deformed by binding to multivalent ligands. Self-assembled ladder-shaped 2:2 complexes were also investigated to illustrate the scope of DEER measurements for providing structural information on synthetic noncovalent nanostructures. PMID:19736940

  15. Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip

    Science.gov (United States)

    Tomak, A.; Bacaksiz, C.; Mendirek, G.; Sahin, H.; Hur, D.; Görgün, K.; Senger, R. T.; Birer, Ö.; Peeters, F. M.; Zareie, H. M.

    2016-08-01

    We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.

  16. Multispectral excitation based multiple fluorescent targets resolving in fluorescence molecular tomography

    Science.gov (United States)

    Zhou, Yuan; Guang, Huizhi; Pu, Huangsheng; Zhang, Jiulou; Bai, Jing; Luo, Jianwen

    2016-04-01

    Fluorescence molecular tomography (FMT) can visualize biological activities at cellular and molecular levels in vivo, and has been extensively used in drug delivery and tumor detection research of small animals. The ill-posedness of the FMT inverse problem makes it difficult to reconstruct and resolve multiple adjacent fluorescent targets that have different functional features but are labeled with the same fluorochrome. An algorithm based on independent component analysis (ICA) for multispectral excited FMT is proposed to resolve multiple fluorescent targets in this study. Fluorescent targets are excited by multispectral excitation, and the three-dimensional distribution of fluorescent yields under the excitation spectrum is reconstructed by an iterative Tikhonov regularization algorithm. Subsequently, multiple fluorescent targets are resolved from mixed fluorescence signals by employing ICA. Simulations were performed and the results demonstrate that multiple adjacent fluorescent targets can be resolved if the number of excitation wavelengths is not smaller than that of fluorescent targets with different concentrations. The algorithm obtains both independent components that provide spatial information of different fluorescent targets and spectral courses that reflect variation trends of fluorescent yields along with the excitation spectrum. By using this method, it is possible to visualize the metabolism status of drugs in different structure organs, and quantitatively depict the variation trends of fluorescent yields of each functional organ under the excitation spectrum. This method may provide a pattern for tumor detection, drug delivery and treatment monitoring in vivo.

  17. Anisotropy induced Kondo splitting in a mechanically stretched molecular junction: A first-principles based study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoli; Hou, Dong, E-mail: houdong@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Xiao, E-mail: xz58@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Normal College, Guiyang, Guizhou 550018 (China); Yan, YiJing [Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong (China)

    2016-01-21

    The magnetic anisotropy and Kondo phenomena in a mechanically stretched magnetic molecular junction are investigated by combining the density functional theory (DFT) and hierarchical equations of motion (HEOM) approach. The system is comprised of a magnetic complex Co(tpy–SH){sub 2} sandwiched between adjacent gold electrodes, which is mechanically stretched in experiments done by Parks et al. [Science 328, 1370 (2010)]. The electronic structure and mechanical property of the stretched system are investigated via the DFT calculations. The HEOM approach is then employed to characterize the Kondo resonance features, based on the Anderson impurity model parameterized from the DFT results. It is confirmed that the ground state prefers the S = 1 local spin state. The structural properties, the magnetic anisotropy, and corresponding Kondo peak splitting in the axial stretching process are systematically evaluated. The results reveal that the strong electron correlations and the local magnetic properties of the molecule magnet are very sensitive to structural distortion. This work demonstrates that the combined DFT+HEOM approach could be useful in understanding and designing mechanically controlled molecular junctions.

  18. Fluorescent molecularly imprinted polymer based on Navicula sp. frustules for optical detection of lysozyme.

    Science.gov (United States)

    Lim, Guat Wei; Lim, Jit Kang; Ahmad, Abdul Latif; Chan, Derek Juinn Chieh

    2016-03-01

    The direct correlation between disease and lysozyme (LYZ) levels in human body fluids makes the sensitive and convenient detection of LYZ the focus of scientific research. Fluorescent molecularly imprinted polymer has emerged as a new alternative for LYZ detection in order to resolve the limitation of immunoassays, which are expensive, unstable, require complex preparation, and are time consuming. In this study, a novel fluorescence molecularly imprinted polymer based on Navicula sp. frustules (FITC-MIP) has been synthesized via post-imprinting treatment for LYZ detection. Navicula sp. frustules were used as supported material because of their unique properties of moderate surface area, reproducibility, and biocompatibility, to address the drawbacks of nanoparticle core material with low adsorption capacity. The FITC acts as recognition signal and optical readout, whereas MIP provides LYZ selectivity. The synthesized FITC-MIP showed a response time as short as 5 min depending on the concentration of LYZ. It is found that the LYZ template can significantly quench the fluorescence intensity of FITC-MIP linearly within a concentration range of 0 to 0.025 mg mL(-1), which is well described by Stern-Volmer equation. The FITC-MIP can selectively and sensitively detect down to 0.0015 mg mL(-1) of LYZ concentration. The excellent sensing performance of FITC-MIP suggests that FITC-MIP is a potential biosensor in clinical diagnosis applications. PMID:26842746

  19. Epitope engineering and molecular metrics of immunogenicity: a computational approach to VLP-based vaccine design.

    Science.gov (United States)

    Joshi, Harshad; Lewis, Kristen; Singharoy, Abhishek; Ortoleva, Peter J

    2013-10-01

    Developing antiviral vaccines is increasingly challenging due to associated time and cost of production as well as emerging drug-resistant strains. A computer-aided vaccine design strategy is presented that could greatly accelerate the discovery process and yield vaccines with high immunogenicity and thermal stability. Our strategy is based on foreign viral epitopes engineered onto well-established virus-like particles (VLPs) and demonstrates that such constructs present similar affinity for antibodies as does a native virus. This binding affinity serves as one molecular metric of immunogenicity. As a demonstration, we engineered a preS1 epitope of hepatitis B virus (HBV) onto the EF loop of human papillomavirus VLP (HPV-VLP). HBV-associated HzKR127 antibody displayed binding affinity for this structure at distances and strengths similar to those for the complex of the antibody with the full HBV (PDBID: 2EH8). This antibody binding affinity assessment, along with other molecular immunogenicity metrics, could be a key component of a computer-aided vaccine design strategy. PMID:23933338

  20. Classification of signaling proteins based on molecular star graph descriptors using Machine Learning models.

    Science.gov (United States)

    Fernandez-Lozano, Carlos; Cuiñas, Rubén F; Seoane, José A; Fernández-Blanco, Enrique; Dorado, Julian; Munteanu, Cristian R

    2015-11-01

    Signaling proteins are an important topic in drug development due to the increased importance of finding fast, accurate and cheap methods to evaluate new molecular targets involved in specific diseases. The complexity of the protein structure hinders the direct association of the signaling activity with the molecular structure. Therefore, the proposed solution involves the use of protein star graphs for the peptide sequence information encoding into specific topological indices calculated with S2SNet tool. The Quantitative Structure-Activity Relationship classification model obtained with Machine Learning techniques is able to predict new signaling peptides. The best classification model is the first signaling prediction model, which is based on eleven descriptors and it was obtained using the Support Vector Machines-Recursive Feature Elimination (SVM-RFE) technique with the Laplacian kernel (RFE-LAP) and an AUROC of 0.961. Testing a set of 3114 proteins of unknown function from the PDB database assessed the prediction performance of the model. Important signaling pathways are presented for three UniprotIDs (34 PDBs) with a signaling prediction greater than 98.0%. PMID:26297890

  1. The effects of zeolite molecular sieve based surface treatments on the properties of wool fabrics

    International Nuclear Information System (INIS)

    Wool is a natural composite fiber, with keratin and keratin-associated proteins as the key molecular components. The outermost surface of wool fibers comprises a hydrophobic lipid layer that can lead to unsatisfactory processing and properties of fabric products. In this study, molecular sieve 5A, a Na+ and Ca2+ exchanged type A zeolite with a 1:1 Si:Al ratio was integrated onto the surface of wool using 3-mercaptopropyl trimethoxy silane. The resultant surface morphology, hydrophilicity and mechanical performance of the treated wool fabrics were then evaluated. Notably, the surface hydrophilicity of wool was observed to increase dramatically. When wool was treated with a dispersion of 2 wt% acetic acid, 2.5 wt% zeolite and 0.3 wt% or more silane, the water contact angle was observed to decrease from an average value of 148° to 0° over a period of approximately 30 s. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, with infrared spectroscopic evaluation indicating strong bonding of the dealuminated zeolite to wool keratins. This application of zeolite showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite-based treatment is a potentially efficient approach to increasing the surface hydrophilicity and modifying other key surface properties of wool and wool fabrics

  2. UV curable lens production using molecular weight controlled PEEK based acrylic oligomer (Ac-PEEK).

    Science.gov (United States)

    İnan, Tulay Y; Yıldız, Emel; Karaca, Birsen; Dogan, Hacer; Vatansever, Alican; Nalbant, Muhammed; Eken, Koray

    2014-08-01

    We produced UV curable lenses with properties blocking short wave UV light. In the UV-curable formulations, we used an oligomer (Ac-PEEK) with another urethan oligomer (Mw = 2000). Radically active, molecular weight controlled Ac-PEEK was obtained by reacting 2-hydroxyl ethyl methacrylate with molecular- weight- controlled and isocyanate terminated PEEK (Mn = 4500). We characterized all synthesized monomer, oligomer and optical materials with UV/Vis spectrophotometer with interferogram, elemental analyser, mass spectrophotometer, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravimetric analyzer, differential scanning calorimeter, scanning electron microscopy and gas chromatography. Results suggested that newly synthesized oligomer with the structure of PEEK absorbs short wave UV-light. Ageing tests [ISO 11979-5, Ophthalmic implants-intraocular lenses (IOL)-Part 5: Biocompatibility] performed on the IOL materials were successful. High contact angle of the obtained lenses suggests that all lenses were hydrophobic and SEM results revealed that lenses are morphologically homogeneous. Based on all positive properties just mentioned, we safely conclude that the lenses produced in this study are very promising for IOL production. PMID:24796625

  3. Molecular Quantum Spintronics: Supramolecular Spin Valves Based on Single-Molecule Magnets and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Wolfgang Wernsdorfer

    2011-10-01

    Full Text Available We built new hybrid devices consisting of chemical vapor deposition (CVD grown carbon nanotube (CNT transistors, decorated with TbPc2 (Pc = phthalocyanine rare-earth based single-molecule magnets (SMMs. The drafting was achieved by tailoring supramolecular π-π interactions between CNTs and SMMs. The magnetoresistance hysteresis loop measurements revealed steep steps, which we can relate to the magnetization reversal of individual SMMs. Indeed, we established that the electronic transport properties of these devices depend strongly on the relative magnetization orientations of the grafted SMMs. The SMMs are playing the role of localized spin polarizer and analyzer on the CNT electronic conducting channel. As a result, we measured magneto-resistance ratios up to several hundred percent. We used this spin valve effect to confirm the strong uniaxial anisotropy and the superparamagnetic blocking temperature (TB ~ 1 K of isolated TbPc2 SMMs. For the first time, the strength of exchange interaction between the different SMMs of the molecular spin valve geometry could be determined. Our results introduce a new design for operable molecular spintronic devices using the quantum effects of individual SMMs.

  4. The effects of zeolite molecular sieve based surface treatments on the properties of wool fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Carran, Richard S.; Ghosh, Arun, E-mail: Arun.Ghosh@agresearch.co.nz; Dyer, Jolon M.

    2013-12-15

    Wool is a natural composite fiber, with keratin and keratin-associated proteins as the key molecular components. The outermost surface of wool fibers comprises a hydrophobic lipid layer that can lead to unsatisfactory processing and properties of fabric products. In this study, molecular sieve 5A, a Na{sup +} and Ca{sup 2+} exchanged type A zeolite with a 1:1 Si:Al ratio was integrated onto the surface of wool using 3-mercaptopropyl trimethoxy silane. The resultant surface morphology, hydrophilicity and mechanical performance of the treated wool fabrics were then evaluated. Notably, the surface hydrophilicity of wool was observed to increase dramatically. When wool was treated with a dispersion of 2 wt% acetic acid, 2.5 wt% zeolite and 0.3 wt% or more silane, the water contact angle was observed to decrease from an average value of 148° to 0° over a period of approximately 30 s. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, with infrared spectroscopic evaluation indicating strong bonding of the dealuminated zeolite to wool keratins. This application of zeolite showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite-based treatment is a potentially efficient approach to increasing the surface hydrophilicity and modifying other key surface properties of wool and wool fabrics.

  5. DNA and RNA "traffic lights": synthetic wavelength-shifting fluorescent probes based on nucleic acid base substitutes for molecular imaging.

    Science.gov (United States)

    Holzhauser, Carolin; Wagenknecht, Hans-Achim

    2013-08-01

    The DNA base substitute approach by the (S)-3-amino-1,2-propanediol linker allows placing two fluorophores in a precise way inside a given DNA framework. The double helical architecture around the fluorophores, especially the DNA-induced twist, is crucial for the desired photophysical interactions. Excitonic, excimer, and energy transfer interactions yield fluorescent DNA and RNA probes with dual emission color readout. Especially, our DNA and RNA "traffic light" that combines the green emission of TO with the red emission of TR represents an important tool for molecular imaging and can be applied as aptasensors and as probes to monitor the siRNA delivery into cells. The concept can be extended to the synthetically easier to access postsynthetic 2'-modifications and the NIR range. Thereby, the pool of tailor-made fluorescent nucleic acid conjugates can be extended. PMID:23796243

  6. 1,8-Naphthalimide-Based Planar Small Molecular Acceptor for Organic Solar Cells.

    Science.gov (United States)

    Zhang, Jicheng; Zhang, Xuejuan; Xiao, Hongmei; Li, Guangwu; Liu, Yahui; Li, Cuihong; Huang, Hui; Chen, Xuebo; Bo, Zhishan

    2016-03-01

    Four small molecular acceptors (SM1-4) comprising a central benzene core, two thiophene bridges and two 1,8-naphthalimide (NI) terminal groups were designed and synthesized by direct C-H activation. SM1 has a planar chemical structure and forms H-aggregation as films. By attachment of different substituents on the central benzene ring, the dihedral angles between the two NI end groups of SM1-4 gradually increased, leading to a gradual decrease of planarity. SM1-4 all possess a high-lying LUMO level, matching with wide band gap (WBG) polymer donors which usually have a high-lying LUMO level. When used in OSCs, devices based on SM1 and WBG donor PCDTBT-C12 gave higher electron mobility, superior film morphology and better photovoltaic performance. After optimization, a PCE of 2.78% with a Voc of 1.04 V was achieved for SM1 based devices, which is among the highest PCEs with a Voc higher than 1 V. Our results have demonstrated that NI based planar small molecules are potential acceptors for WBG polymer based OSCs. PMID:26845638

  7. Molecular systematics of Volvocales (Chlorophyceae, Chlorophyta) based on exhaustive 18S rRNA phylogenetic analyses.

    Science.gov (United States)

    Nakada, Takashi; Misawa, Kazuharu; Nozaki, Hisayoshi

    2008-07-01

    The taxonomy of Volvocales (Chlorophyceae, Chlorophyta) was traditionally based solely on morphological characteristics. However, because recent molecular phylogeny largely contradicts the traditional subordinal and familial classifications, no classification system has yet been established that describes the subdivision of Volvocales in a manner consistent with the phylogenetic relationships. Towards development of a natural classification system at and above the generic level, identification and sorting of hundreds of sequences based on subjective phylogenetic definitions is a significant step. We constructed an 18S rRNA gene phylogeny based on 449 volvocalean sequences collected using exhaustive BLAST searches of the GenBank database. Many chimeric sequences, which can cause fallacious phylogenetic trees, were detected and excluded during data collection. The results revealed 21 strongly supported primary clades within phylogenetically redefined Volvocales. Phylogenetic classification following PhyloCode was proposed based on the presented 18S rRNA gene phylogeny along with the results of previous combined 18S and 26S rRNA and chloroplast multigene analyses. PMID:18430591

  8. Isoindigo-based polymer photovoltaics: modifying polymer molecular structures to control the nanostructural packing motif.

    Science.gov (United States)

    Kim, Yu Jin; Lee, Yun-Ji; Kim, Yun-Hi; Park, Chan Eon

    2016-07-21

    Donor molecular structures, and their packing aspects in donor:acceptor active blends, play a crucial role in the photovoltaic performance of polymer solar cells. We systematically investigated a series of isoindigo-based donor polymers within the framework of a three-dimensional (3D) crystalline motif by modifying their chemical structures, thereby affecting device performances. Although our isoindigo-based polymer series contained polymers that differed only by their alkyl side chains and/or donating units, they showed quite different nanoscale morphological properties, which resulted in significantly different device efficiencies. Notably, blends of our isoindigo-based donor polymer systems with an acceptor compound, whereby the blends had more intermixed network morphologies and stronger face-on orientations of the polymer crystallites, provided better-performing photovoltaic devices. This behavior was analyzed using atomic force microscopy (AFM) and two-dimensional grazing incidence wide angle X-ray diffraction (2D-GIWAXD). To the best of our knowledge, no correlation has been reported previously between 3D nano-structural donor crystallites and device performances, particularly for isoindigo-based polymer systems. PMID:27326694

  9. Flavanols and vascular health: molecular mechanisms to build evidence-based recommendations.

    Science.gov (United States)

    Fraga, Cesar G; Oteiza, Patricia

    2014-10-01

    Observational studies as well as public awareness and ancient medicine identify tea, wine and cocoa as healthy foods. Further compilations of epidemiological data reinforce the healthy properties of the grape, tea and cocoa derived foods and drinks made from, especially when considering cardiovascular disease, some cancers and other inflammation-related pathologies. Flavanols have emerged as bioactives responsible for such health effects, and flavanol-rich foods have been used in clinical studies. Results of these studies show a major participation of flavanols in mechanisms positively affecting endpoints of cardiovascular disease, i.e. hypertension and vascular function. In line, based on the chemistry (bioavailability and molecular structure of flavanol and target entities) several physiological mechanisms have been described backing the epidemiological and clinical studies. In summary, the discussion for defining evidence-based recommendations for flavanols is based on: a) the extensive research done and the positive results obtained support the incorporation of flavanol-rich foods as part of a healthy diet, this is a cost-effective action to ameliorate silent undesirable conditions as it is chronic inflammation; b) the fact that cardiovascular health seems especially sensitive to the beneficial effects of flavanols: based on clinical and mechanistic studies showing that certain flavanols, favor NO production; and c) the increasing technical possibilities to evaluate flavanols in foods and biological samples. Supported by UBACyT 20020120100177, CONICET PIP-20110100752, and ANPCyT PICT 2012/0765. PMID:26461285

  10. COMPOSITE POLYMERICADDITIVESDESIGNATED FORCONCRETEMIXES BASED ONPOLYACRYLATES, PRODUCTS OF THERMAL DECOMPOSITION OF POLYAMIDE-6 AND LOW-MOLECULAR POLYETHYLENE

    OpenAIRE

    Polyakov Vyacheslav Sergeevich; Padokhin Valeriy Alekseevich; Akulova Marina Vladimirovna -

    2012-01-01

    The goal of the present research is to develop polymeric additives based on aqueous dispersions of (meth)acrylic polymers, including polymethacrylates, polyacrylates, products of thermal decomposition of polyamide-6 in the vegetable oil media, and low-molecular polyethylene. Decomposition of polyamide-6 took 8…10 hours at the temperature of 245…275 °С. The mixture of low-molecular polyamides, the average molecular weight of which reached 3400…8600, was used both independently and as a consti...

  11. Research Update: Comparison of salt- and molecular-based iodine treatments of PbS nanocrystal solids for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jähnig, Fabian; Bozyigit, Deniz; Yarema, Olesya; Wood, Vanessa [Laboratory for Nanoelectronics, ETH Zurich Gloriastrasse 35, Zurich 8044 (Switzerland)

    2015-02-01

    Molecular- and salt-based chemical treatments are believed to passivate electronic trap states in nanocrystal-based semiconductors, which are considered promising for solar cells but suffer from high carrier recombination. Here, we compare the chemical, optical, and electronic properties of PbS nanocrystal-based solids treated with molecular iodine and tetrabutylammonium iodide. Surprisingly, both treatments increase—rather than decrease—the number density of trap states; however, the increase does not directly influence solar cell performance. We explain the origins of the observed impact on solar cell performance and the potential in using different chemical treatments to tune charge carrier dynamics in nanocrystal-solids.

  12. La importancia de la determinación del Factor X activado para la anticoagulación con heparinas de bajo peso molecular: Experiencia en el Hospital San Juan de Dios, 2009-2011 (Primer Reporte) The importance of the determination of Factor X acivated for anticoagulation with low molecular weight heparins experience at the Hospital San Juan de Dios. (First report) 2009-2011

    OpenAIRE

    Lizbeth Salazar-Sanchez; Allan Ramos; Jorge Arauz; Juan José Madrigal; Mayra Cartín B.; Daniel Guzmán

    2012-01-01

    La anticoagulación con heparinas de bajo peso molecular (HBPM) es una herramienta terapéutica fundamental para el tratamiento de la enfermedad tromboembólica. En el presente reporte se evidencia la importancia de cuantificar la actividad del anticuerpo antifactor X activado (Xa) para el monitoreo de la enoxaparina y analizar los grupos de pacientes en riesgo de tener niveles inferiores al terapéutico. Métodos: Se estudiaron 34 pacientes adultos, anticoagulados con enoxaparina durante el perio...

  13. Treatment of Chronic Inflammatory Demyelinating Polyneuropathy: From Molecular Bases to Practical Considerations

    Directory of Open Access Journals (Sweden)

    Paolo Ripellino

    2014-01-01

    Full Text Available Chronic inflammatory demyelinating polyneuropathy (CIDP is an autoimmune disease of the peripheral nervous system, in which both cellular and humoral immune responses are involved. The disease is clinically heterogeneous with some patients displaying pure motor form and others also showing a variable degree of sensory dysfunction; disease evolution may also differ from patient to patient, since monophasic, progressive, and relapsing forms are reported. Underlying such clinical variability there is probably a broad spectrum of molecular dysfunctions that are and will be the target of therapeutic strategies. In this review we first explore the biological bases of current treatments and subsequently we focus on the practical management that must also take into account pharmacoeconomic issues.

  14. Paramagnetic molecule induced strong antiferromagnetic exchange coupling on a magnetic tunnel junction based molecular spintronics device

    Science.gov (United States)

    Tyagi, Pawan; Baker, Collin; D'Angelo, Christopher

    2015-07-01

    This paper reports our Monte Carlo (MC) studies aiming to explain the experimentally observed paramagnetic molecule induced antiferromagnetic coupling between ferromagnetic (FM) electrodes. Recently developed magnetic tunnel junction based molecular spintronics devices (MTJMSDs) were prepared by chemically bonding the paramagnetic molecules between the FM electrodes along the tunnel junction’s perimeter. These MTJMSDs exhibited molecule-induced strong antiferromagnetic coupling. We simulated the 3D atomic model analogous to the MTJMSD and studied the effect of molecule’s magnetic couplings with the two FM electrodes. Simulations show that when a molecule established ferromagnetic coupling with one electrode and antiferromagnetic coupling with the other electrode, then theoretical results effectively explained the experimental findings. Our studies suggest that in order to align MTJMSDs’ electrodes antiparallel to each other, the exchange coupling strength between a molecule and FM electrodes should be ˜50% of the interatomic exchange coupling for the FM electrodes.

  15. Use of gadoxetate disodium for functional MRI based on its unique molecular mechanism.

    Science.gov (United States)

    Choi, YoonSeok; Huh, Jimi; Woo, Dong-Cheol; Kim, Kyung Won

    2016-01-01

    Gadolinium ethoxybenzyl dimeglumine (gadoxetate) is a recently developed hepatocyte-specific MRI contrast medium. Gadoxetate demonstrates unique pharmacokinetic and pharmacodynamic properties, because its uptake in hepatocytes occurs via the organic anion transporting polypeptide (OATP) transporter expressed at the sinusoidal membrane, and its biliary excretion via the multidrug resistance-associated proteins (MRPs) at the canalicular membrane. Based on these characteristics, gadoxetate-enhanced MRI can provide functional information on hepatobiliary diseases, including liver function estimation, biliary drainage evaluation and characterization of hepatocarcinogenesis. In addition, understanding its mode of action can provide an opportunity to use gadoxetate for cellular and molecular imaging. Radiologists and imaging scientists should be familiar with the basic mechanism of gadoxetate and OATP/MRP transporters. PMID:26693795

  16. Detection of molecular charge dynamics through current noise in a GaAs-based nanowire FET

    Science.gov (United States)

    Inoue, Shinya; Kuroda, Ryota; Yin, Xiang; Sato, Masaki; Kasai, Seiya

    2015-04-01

    The detection of static and dynamic molecular charge states using a GaAs-based nanowire field-effect transistor (FET) was investigated. Tetraphenylporphyrin (TPP) was put on the device as target molecules. After coating TPP on the FET, the drain current clearly decreased. On the other hand, the current largely increased by 405-nm light irradiation, indicating that TPP worked as a photo-excited donor. The light irradiation on the FET also induced a Lorentzian noise component, which was superimposed onto conventional 1/f noise. These behaviors were not seen in the gateless nanowire even with TPP. The obtained results indicated that electrical interaction between TPP and the nanowire was enhanced when a metal gate existed, although the channel was protected from TPP by the gate metal. We discuss the observed behaviors on the basis of a model where only TPP in the gate periphery modulated the channel potential and the drain current.

  17. Deformation characteristics of various grain boundary angles on AFM-based nanolithography using molecular dynamics

    International Nuclear Information System (INIS)

    Molecular dynamics simulations are performed to verify the deformation characteristics of grain boundaries on the AFM-based nanolithography. The model used has about 750,000 (Cu) atoms and is composed of two different crystal orientations. The grain boundaries are located in the center of model and have 45, 90, 135, and -135 degree angles in the xz-plane. The tool is made of rigid diamond-like carbon and is in the shape of the Berkovich indenter. The simulation has four different stages: relaxation, indentation, re-relaxation, and lithography. The simulation results reveal that the lithography deforms the grain boundary shape by the tool. The deformation of grain boundary's angle proceeds to minimize the total potential energy of whole system. Consequently, the grain boundary angle is changed about 90 degrees

  18. Protein kinase inhibitor-induced endothelial cell cytotoxicity and its prediction based on calculated molecular descriptors.

    Science.gov (United States)

    Herczenik, Eszter; Varga, Zoltán; Eros, Dániel; Makó, Veronika; Oroszlán, Melinda; Rugonfalvi-Kiss, Szabolcs; Romics, László; Füst, George; Kéri, György; Orfi, László; Cervenak, László

    2009-01-01

    Protein kinase inhibitors (PKIs) as potent signal transduction therapeutic compounds represent a very rapidly expanding group of anticancer drugs. These agents may be toxic for endothelial cells, however, very few experimental data exist on the cytotoxicity of PKIs. The aim of this study was to set up an appropriate test system for endothelial cells and to assess the structure-related cytotoxic effects of a selected library of PKIs. The inhibitor library contains several lead molecules with different basic structures and a set of modified derivatives of the lead compounds. The toxicity of PKIs did not correlate directly with the structural features of the molecules. However, we successfully built up a model based on 15 calculated molecular descriptors, which is capable of predicting cytotoxicity with acceptable probability. Our results show that the cytotoxic effects of PKIs should be taken into account for optimal drug development to overcome endothelial cell-related side effects. PMID:19519173

  19. Application of rbcL based molecular diversity analysis to algae in wastewater treatment plants.

    Science.gov (United States)

    Ghosh, Sudeshna; Love, Nancy G

    2011-02-01

    The molecular diversity of algae in the final clarifier or denitrification filter outfall from three wastewater treatment plants (WWTPs) with activated sludge based treatment was analyzed using the rbcL gene as a phylogenetic marker. The rbcL gene encodes the large subunit of the CO(2) fixing enzyme RuBisCO. Among algae identified at the WWTPs were diatoms, green algae, cyanobacteria, Eustigmatophyceae, and unknown heterokonts. A high level of diversity was observed within WWTPs with 19-24 unique rbcL sequences detected at each plant. Algae composition also varied between treatment plants. Our results show that the rbcL gene can be used as a phylogenetic marker for algae diversity analysis in a wastewater treatment context. PMID:21130646

  20. Molecular typing of Acinetobacter baumannii by automated repetitive-sequence-based PCR

    Directory of Open Access Journals (Sweden)

    Giuseppe Russello

    2011-03-01

    Full Text Available Acinetobacter baumannii has been increasingly reported as a significant causative organism of various nosocomial infections. Here we describe three different outbreaks of multidrug resistant A. baumannii started in the Intensitive Care Unit and then involving other wards of San Carlo Borromeo hospital in Milan, Italy. In order to characterize the clinical strains isolates, molecular typing using semi-automated repetitive-sequence-based PCR (rep-PCR was performed.Among the sixty-one strains analyzed, three main cluster (C1, C2, C3 were detected: C1 included six indistinguishable strains, C2 five and C3 thirty. No correlation was observed between chemosensitivity and ribotyping pattern and an high rate of carbapenems resistance was founded.

  1. A micro seismometer based on molecular electronic transducer technology for planetary exploration

    International Nuclear Information System (INIS)

    This letter describes an implementation of micromachined seismometer based on molecular electronic transducer (MET) technology. As opposed to a solid inertial mass, MET seismometer senses the movement of liquid electrolyte relative to fixed electrodes. The employment of micro-electro-mechanical systems techniques reduces the internal size of the sensing cell to 1μm and improves the reproducibility of the device. For operating bias of 600 mV, a sensitivity of 809 V/(m/s2) was measured under acceleration of 400μg(g≡9.81m/s2) at 0.32 Hz. A −115 dB (relative to (m/s2)/√(Hz)) noise level at 1 Hz was achieved. This work develops an alternative paradigm of seismic sensing device with small size, high sensitivity, low noise floor, high shock tolerance, and independence of installation angle, which is promising for next generation seismometers for planetary exploration.

  2. A molecular simulation-based method for the estimation of activity coefficients for alkane solutions

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Epaminondas, Voutsas; Dimitrios, Tassios

    1996-01-01

    In a recent study Sheng et al. (1995, A.I. Ch.E. J. 41 (10) 2306-2313) presented activity coefficients calculated by molecular simulation (MS) for athermal model polymer-solvent systems. Both activity coefficients of the monomeric solvent in the polymer (gamma(1)(infinity)) and of the polymer...... compared with classical and recently proposed free-volume (FV) activity coefficient models in order to conclude on the suitability of the models for phase equilibrium calculations for asymmetric systems. On the basis of the work by Sheng et al., extrapolation methods for estimating the activity coefficient...... of a solvent and that of a polymer in real solvent-polymer systems are developed here. The so-obtained MS-based activity coefficients are compared with experimental data (in the case of solvent activities) and with the predictions of various activity coefficients models (in the case of polymer activities...

  3. Preparation of electrochemical sensor for lead(II) based on molecularly imprinted film

    Science.gov (United States)

    Wang, Zhihua; Qin, Yaxin; Wang, Chu; Sun, Lijun; Lu, Xiaole; Lu, Xiaoquan

    2012-01-01

    A high selective voltammetric sensor for Pb2+ was introduced. The feasibility of utilizing strong interactions between Schiff bases and metal ion to prepare the molecularly imprinted polymers (MIPs) electrochemical sensor for Pb2+ in aqueous solutions was studied. Some parameters affecting sensor response were optimized and then a calibration curve was plotted. A dynamic linear range of 3.00 × 10-7 to 5.00 × 10-5 mol/L was obtained. The redox process of Pb2+ on the imprinted electrode is controlled by surface reaction. The stability and the life of imprinted membrane were improved by storing into diluted Pb2+ ion solution. The proposed method was applied to determination of Pb2+ in the Yellow River.

  4. Isopropylation of benzene with 2-propanol over substituted large pore aluminophosphate-based molecular sieves

    Indian Academy of Sciences (India)

    K Joseph Antony Raj; V R Vijayaraghavan

    2004-03-01

    Large pore aluminophosphate-based molecular sieves like AlPO4-5, MAPO-5, MnAPO-5 and ZAPO-5 were synthesised hydrothermally using triethylamine as a structure directing agent. These materials were characterised by X-ray diffraction (XRD), 27Al and 31P MAS-NMR, ICP-MS, -butylamine- TPD, BET and SEM. The catalytic performance of these materials was tested for isopropylation of benzene with 2-propanol at 250, 300, 350 and 400°C. The products were cumene, -DIPB (-diisopropylbenzene) and -DIPB (-diisopropylbenzene). MnAPO-5 was found to be more active than the other catalysts. Maximum conversion (20%) was noted at 350°C over MnAPO-5. The selectivity to DIPB was found to decrease with time on stream but the selectivity to cumene showed an increase after 3 h of time on stream.

  5. Asymptotic Analysis of Microtubule-Based Transport by Multiple Identical Molecular Motors

    CERN Document Server

    McKinley, Scott A; Fricks, John; Kramer, Peter R

    2011-01-01

    We describe a system of stochastic differential equations (SDEs) which model the interaction between processive molecular motors, such as kinesin and dynein, and the biomolecular cargo they tow as part of microtubule-based intracellular transport. We show that the classical experimental environment fits within a parameter regime which is qualitatively distinct from conditions one expects to find in living cells. Through an asymptotic analysis of our system of SDEs, we develop a means for applying in vitro observations of the nonlinear response by motors to forces induced on the attached cargo to make analytical predictions for two parameter regimes that have thus far eluded direct experimental observation: 1) highly viscous in vivo transport and 2) dynamics when multiple identical motors are attached to the cargo and microtubule.

  6. Prediction of Substrate-Enzyme-Product Interaction Based on Molecular Descriptors and Physicochemical Properties

    Directory of Open Access Journals (Sweden)

    Bing Niu

    2013-01-01

    Full Text Available It is important to correctly and efficiently predict the interaction of substrate-enzyme and to predict their product in metabolic pathway. In this work, a novel approach was introduced to encode substrate/product and enzyme molecules with molecular descriptors and physicochemical properties, respectively. Based on this encoding method, KNN was adopted to build the substrate-enzyme-product interaction network. After selecting the optimal features that are able to represent the main factors of substrate-enzyme-product interaction in our prediction, totally 160 features out of 290 features were attained which can be clustered into ten categories: elemental analysis, geometry, chemistry, amino acid composition, predicted secondary structure, hydrophobicity, polarizability, solvent accessibility, normalized van der Waals volume, and polarity. As a result, our predicting model achieved an MCC of 0.423 and an overall prediction accuracy of 89.1% for 10-fold cross-validation test.

  7. Prediction of substrate-enzyme-product interaction based on molecular descriptors and physicochemical properties.

    Science.gov (United States)

    Niu, Bing; Huang, Guohua; Zheng, Linfeng; Wang, Xueyuan; Chen, Fuxue; Zhang, Yuhui; Huang, Tao

    2013-01-01

    It is important to correctly and efficiently predict the interaction of substrate-enzyme and to predict their product in metabolic pathway. In this work, a novel approach was introduced to encode substrate/product and enzyme molecules with molecular descriptors and physicochemical properties, respectively. Based on this encoding method, KNN was adopted to build the substrate-enzyme-product interaction network. After selecting the optimal features that are able to represent the main factors of substrate-enzyme-product interaction in our prediction, totally 160 features out of 290 features were attained which can be clustered into ten categories: elemental analysis, geometry, chemistry, amino acid composition, predicted secondary structure, hydrophobicity, polarizability, solvent accessibility, normalized van der Waals volume, and polarity. As a result, our predicting model achieved an MCC of 0.423 and an overall prediction accuracy of 89.1% for 10-fold cross-validation test. PMID:24455714

  8. Microspheres Sensor Based on Molecularly Imprinted Polymer Synthesized by Precipitation Polymerization

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Zhao-Hui; LONG,Yu-Mei; LIU,Ying-Ju; YAO,Shou-Zhuo

    2003-01-01

    A new biomimetic bulk acoustic wave sensor based on molecularly imprinted microspheres(MIM) technique was described.The sensing materials were synthesized by precipitation polymerization.By using the Scatchard analysis,the equilibrium dissociation constant KD and the apparent maximum number Qmax of the binding sites were calculated to be 3.70 mmol·L-1 and 9.11 μmol·g-1,respectively.The sensor exhibited a sensitive response to detection limit of 2×10-9 mol·L-1.The recoveries of the sensor were 95.1%-105.4%.Studies presented in this paper show that the stability of this sensor is excellent.The sensor has been applied successfully to the determination of dipyridmaole in human urine.

  9. Multilayer Edge Molecular Devices Based on Plasma Oxidation of Photolithographically Defined Bottom Metal Electrode

    OpenAIRE

    Tyagi, Pawan

    2011-01-01

    A multilayer edge molecular electronics device (MEMED), which utilize the two metal electrodes of a metal-insulator-metal tunnel junction as the two electrical leads to molecular channels, can overcome the long standing fabrication challenges for developing futuristic molecular devices. However, producing ultrathin insulator is the most challenging step in MEMED fabrication. A simplified molecular device approach was developed by avoiding the need of depositing a new materiel on the bottom el...

  10. Molecular bases for parallel evolution of translucent bracts in an alpine "glasshouse" plant Rheum alexandrae (Polygonaceae)

    Institute of Scientific and Technical Information of China (English)

    Bing-Bing LIU; Lars OPGENOORTH; Georg MIEHE; Dong-Yuan ZHANG; Dong-Shi WAN; Chang-Ming ZHAO; Dong-Rui JIA

    2013-01-01

    Parallel evolution provides an excellent framework to infer the genetic bases of adaptive traits and understand the importance of natural selection in shaping current biodiversity.The upper leaves of the "glasshouse plants" transform into translucent bracts that show numerous adaptions in alpine habitats.It remains unknown whether similar molecular changes occur under the parallel bract evolution of different "glasshouse" species.In this study,we compared the results on phenotypic and physiological differences and presented the results of cDNA-AFLP analyses of transcriptional changes between translucent bracts and normal leaves in Rheum alexandrae.We also examined the homologous candidate genes with the same expression changes between this species and another "glasshouse" species,R.nobile.We found that bracts ofR.alexandrae are similar to those ofR.nobile in anatomical features:chloroplasts have degenerated and chlorophyll contents are greatly reduced,which suggests that foliar photosynthetic functions in bracts of both species have been reduced or totally altered.Among the 6000 transcript-derived fragments (TDFs) in bracts and leaves of R.alexandrae,420 (7%) were differentially expressed (up-or downregulated) between bracts and normal leaves.There were a total of 13 homologous TDFs with the same expression changes between R.alexandrae and the previously studied R.nobile.Except for the two that were not functionally annotated,eight of the homologous TDFs were found to be involved in stress and defense responses whereas the other three were related to photosynthesis.The up-or downregulation of these candidate genes was highly congruent with anatomical characteristics and adaptive functions of the bracts found for "glasshouse" plants.These findings suggested that the "glasshouse" phenotypes may have common molecular bases underlying their parallel evolution of similar adaptive functions and highlighted the importance of the natural selection in producing such

  11. Molecular epidemiology of Plasmodium species prevalent in Yemen based on 18 s rRNA

    Directory of Open Access Journals (Sweden)

    A Azazy Ahmed

    2010-11-01

    Full Text Available Abstract Background Malaria is an endemic disease in Yemen and is responsible for 4.9 deaths per 100,000 population per year and 43,000 disability adjusted life years lost. Although malaria in Yemen is caused mainly by Plasmodium falciparum and Plasmodium vivax, there are no sequence data available on the two species. This study was conducted to investigate the distribution of the Plasmodium species based on the molecular detection and to study the molecular phylogeny of these parasites. Methods Blood samples from 511 febrile patients were collected and a partial region of the 18 s ribosomal RNA (18 s rRNA gene was amplified using nested PCR. From the 86 positive blood samples, 13 Plasmodium falciparum and 4 Plasmodium vivax were selected and underwent cloning and, subsequently, sequencing and the sequences were subjected to phylogenetic analysis using the neighbor-joining and maximum parsimony methods. Results Malaria was detected by PCR in 86 samples (16.8%. The majority of the single infections were caused by P. falciparum (80.3%, followed by P. vivax (5.8%. Mixed infection rates of P. falciparum + P. vivax and P. falciparum + P. malariae were 11.6% and 2.3%, respectively. All P. falciparum isolates were grouped with the strain 3D7, while P. vivax isolates were grouped with the strain Salvador1. Phylogenetic trees based on 18 s rRNA placed the P. falciparum isolates into three sub-clusters and P. vivax into one cluster. Sequence alignment analysis showed 5-14.8% SNP in the partial sequences of the 18 s rRNA of P. falciparum. Conclusions Although P. falciparum is predominant, P. vivax, P. malariae and mixed infections are more prevalent than has been revealed by microscopy. This overlooked distribution should be considered by malaria control strategy makers. The genetic polymorphisms warrant further investigation.

  12. Application of fluorescence-based semi-automated allelotyping to the molecular characterization of tumors

    Energy Technology Data Exchange (ETDEWEB)

    Jedlicka, A.E.; DiSilvestre, D.; Holroyd, K.J. [Johns Hopkins Medical Institutions, Baltimore, MD (United States)] [and others

    1994-09-01

    In cancer genetics, identifying loss of heterozygosity (LOH) defines candidate regions which warrant further analyses to determine the presence of tumor suppressor genes. In addition, demonstrating LOH has potential utility for improving the pathologic classification of tumors. Molecular methods that improve the efficiency and accuracy of LOH studies will be helpful in both clinical and research applications. Here we demonstrate a fluorescence-based semi-automated alleotyping method for studies of LOH in cancer, using gliomas as an example. Gliomas are tumors arising from neuroglia, the supporting tissue intermingled with essential elements of the brain and spinal cord. Since this method utilizes PCR-based highly polymorphic simple sequence repeat markers, it is suitable for small and archival tumor specimens. We collected tumor tissue from a variety of gliomas, and DNA was extracted. White blood cells from the same individuals served as a source of {open_quotes}control{close_quotes} DNA. We PCR amplified markers from tumor and genomic DNA to detect molecular alterations in six people. Simultaneous analysis of 14 loci near gene candidates on chromosomes 5, 7, 9, 10, 11, and 22, were evaluated. Strikingly, in most cases there was allelic loss in brain tumor compared to genomic DNA for at least one of these loci. In addition, alleles of lesser intensity were also shown at a few loci of the tumor DNA, suggesting possible genetic instability. We conclude from these data that fluorescent semi-automated allelotyping is a quantitative and efficient process for determining and analyzing LOH in gliomas, and possibly other tumors. These methods will facilitate the identification of candidate loci critical in the development and progression of tumors.

  13. Design and Synthesis of Chiral Molecular Tweezers Based on Deoxycholic Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms.Instead of using toxic phosgene,the triphosgene was employed in synthesis of the molecular tweezers receptors.These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

  14. Electrochemical control of quantum interference in anthraquinone-based molecular switches

    DEFF Research Database (Denmark)

    Markussen, Troels; Schiøtz, Jakob; Thygesen, Kristian Sommer

    2010-01-01

    absent in the hydroquinone molecular bridge. A simple explanation of the interference effect is achieved by transforming the frontier molecular orbitals into localized molecular orbitals thereby obtaining a minimal tight-binding model describing the transport in the relevant energy range in terms of...

  15. Finding a Potential Dipeptidyl Peptidase-4 (DPP-4) Inhibitor for Type-2 Diabetes Treatment Based on Molecular Docking, Pharmacophore Generation, and Molecular Dynamics Simulation.

    Science.gov (United States)

    Meduru, Harika; Wang, Yeng-Tseng; Tsai, Jeffrey J P; Chen, Yu-Ching

    2016-01-01

    Dipeptidyl peptidase-4 (DPP-4) is the vital enzyme that is responsible for inactivating intestinal peptides glucagon like peptide-1 (GLP-1) and Gastric inhibitory polypeptide (GIP), which stimulates a decline in blood glucose levels. The aim of this study was to explore the inhibition activity of small molecule inhibitors to DPP-4 following a computational strategy based on docking studies and molecular dynamics simulations. The thorough docking protocol we applied allowed us to derive good correlation parameters between the predicted binding affinities (pKi) of the DPP-4 inhibitors and the experimental activity values (pIC50). Based on molecular docking receptor-ligand interactions, pharmacophore generation was carried out in order to identify the binding modes of structurally diverse compounds in the receptor active site. Consideration of the permanence and flexibility of DPP-4 inhibitor complexes by means of molecular dynamics (MD) simulation specified that the inhibitors maintained the binding mode observed in the docking study. The present study helps generate new information for further structural optimization and can influence the development of new DPP-4 inhibitors discoveries in the treatment of type-2 diabetes. PMID:27304951

  16. [Genetic polymorphism of flax Linum usitatissimum based on use of molecular cytogenetic markers].

    Science.gov (United States)

    Rachinskaia, O A; Lemesh, V A; Muravenko, O V; Iurkevich, O Iu; Guzenko, E V; Bol'sheva, N L; Bogdanova, M V; Samatadze, T E; Popov, K V; Malyshev, S V; Shostak, N G; Heller, K; Khotyleva, L V; Zelenin, A V

    2011-01-01

    Using a set of approaches based on the use of molecular cytogenetic markers (DAPI/C-banding, estimation of the total area of DAPI-positive regions in prophase nuclei, FISH with 26S and 5S rDNA probes) and the microsatellite (SSR-PCR) assay, we studied genomic polymorphism in 15 flax (Linum usitatissimum L.) varieties from different geographic regions belonging to three directions of selection (oil, fiber, and intermediate flaxes) and in the k-37 x Viking hybrid. All individual chromosomes have been identified in the karyotypes of these varieties on the basis of the patterns of differential DAPI/C-banding and the distribution of 26S and 5S rDNA, and idiograms of the chromosomes have been generated. Unlike the oil flax varieties, the chromosomes in the karyotypes of the fiber flax varieties have, as a rule, pericentromeric and telomeric DAPI-positive bands of smaller size, but contain larger intercalary regions. Two chromosomal rearrangements (chromosome 3 inversions) were discovered in the variety Luna and in the k-37 x Viking hybrid. In both these forms, no colocalization of 26S rDNA and 5S rDNA on the satellite chromosome was detected. The SSR assay with the use of 20 polymorphic pairs of primers revealed 22 polymorphic loci. Based on the SSR data, we analyzed genetic similarity of the flax forms studied and constructed a genetic similarity dendrogram. The genotypes studied here form three clusters. The oil varieties comprise an independent cluster. The genetically related fiber flax varieties Vita and Luna, as well as the landrace Lipinska XIII belonging to the intermediate type, proved to be closer to the oil varieties than the remaining fiber flax varieties. The results of the molecular chromosomal analysis in the fiber and oil flaxes confirm their very close genetic similarity. In spite of this, the combined use of the chromosomal and molecular markers has opened up unique possibilities for describing the genotypes of flax varieties and creating their genetic

  17. Molecular-Based Optical Measurement Techniques for Transition and Turbulence in High-Speed Flow

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Cutler, Andrew D.

    2013-01-01

    High-speed laminar-to-turbulent transition and turbulence affect the control of flight vehicles, the heat transfer rate to a flight vehicle's surface, the material selected to protect such vehicles from high heating loads, the ultimate weight of a flight vehicle due to the presence of thermal protection systems, the efficiency of fuel-air mixing processes in high-speed combustion applications, etc. Gaining a fundamental understanding of the physical mechanisms involved in the transition process will lead to the development of predictive capabilities that can identify transition location and its impact on parameters like surface heating. Currently, there is no general theory that can completely describe the transition-to-turbulence process. However, transition research has led to the identification of the predominant pathways by which this process occurs. For a truly physics-based model of transition to be developed, the individual stages in the paths leading to the onset of fully turbulent flow must be well understood. This requires that each pathway be computationally modeled and experimentally characterized and validated. This may also lead to the discovery of new physical pathways. This document is intended to describe molecular based measurement techniques that have been developed, addressing the needs of the high-speed transition-to-turbulence and high-speed turbulence research fields. In particular, we focus on techniques that have either been used to study high speed transition and turbulence or techniques that show promise for studying these flows. This review is not exhaustive. In addition to the probe-based techniques described in the previous paragraph, several other classes of measurement techniques that are, or could be, used to study high speed transition and turbulence are excluded from this manuscript. For example, surface measurement techniques such as pressure and temperature paint, phosphor thermography, skin friction measurements and

  18. Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity

    Science.gov (United States)

    Fernandes, E.K.K.; Keyser, C.A.; Chong, J.P.; Rangel, D.E.N.; Miller, M.P.; Roberts, D.W.

    2010-01-01

    Aims: The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties. Methods and Results: Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5??8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 ?? 0??2??C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5??C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG). Conclusions: Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties. Significance and Impact of the Study: Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes. ?? 2009 The Society for Applied Microbiology.

  19. Predicting Molecular Targets for Small-Molecule Drugs with a Ligand-Based Interaction Fingerprint Approach.

    Science.gov (United States)

    Cao, Ran; Wang, Yanli

    2016-06-20

    The computational prediction of molecular targets for small-molecule drugs remains a great challenge. Herein we describe a ligand-based interaction fingerprint (LIFt) approach for target prediction. Together with physics-based docking and sampling methods, we assessed the performance systematically by modeling the polypharmacology of 12 kinase inhibitors in three stages. First, we examined the capacity of this approach to differentiate true targets from false targets with the promiscuous binder staurosporine, based on native complex structures. Second, we performed large-scale profiling of kinase selectivity on the clinical drug sunitinib by means of computational simulation. Third, we extended the study beyond kinases by modeling the cross-inhibition of bromodomain-containing protein 4 (BRD4) for 10 well-established kinase inhibitors. On this basis, we made prospective predictions by exploring new kinase targets for the anticancer drug candidate TN-16, originally known as a colchicine site binder and microtubule disruptor. As a result, p38α was highlighted from a panel of 187 different kinases. Encouragingly, our prediction was validated by an in vitro kinase assay, which showed TN-16 as a low-micromolar p38α inhibitor. Collectively, our results suggest the promise of the LIFt approach in predicting potential targets for small-molecule drugs. PMID:26222196

  20. APRENDIENDO CON LAS TIC: UNA EXPERIENCIA UNIVERSITARIA (LEARNING FROM THE ICTS: A UNIVERSITY EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Regueyra Edelman María Gabriela

    2011-06-01

    Full Text Available Resumen:Se comparte en este artículo la experiencia del uso de las TIC en dos cursos que se imparten en la carrera de Trabajo Social de la Universidad de Costa Rica. Se detallan los recursos tecnológicos utilizados y el uso que se da a cada uno: Facebook, Blogger, Moodle, correo electrónico, se complementa la experiencia con la incorporación de las opiniones de la población estudiantil matriculada en los cursos y destacando los retos que el uso de las TIC presenta a la población docentes en particular y a la Universidad de Costa Rica en general. El artículo retoma discusión de la Sociedad del Conocimiento y la Información, y las TIC como procesos que han transformado la sociedad actual, con su incorporación tanto en el campo económico, social y laboral como en los ámbitos educativo, familiar y personal, lo que ha generado nuevas interacciones sociales y una brecha entre la población que tiene acceso a la tecnología y la que no lo tiene, situación que ha impactado fundamentalmente el ámbito educativo, donde se han ido incorporando las TIC de manera progresiva, con algunas reservas tanto de la población docente como de la población estudiantil.Abstract: This article deals with the experience of using the Information and Communication Technologies (ICTs for two courses in the Social Work Major at the University of Costa Rica. The use of technological resources such as Facebook, Blogger, Moodle and e-mail are described. The usability of this experience is complemented with opinions from students who registered in those courses, by highlighting the challenges encountered by faculty in particular and by the University of Costa Rica in general, regarding the implementation of ICTs. This article recognizes that the Community and Information-Based Knowledge and the ICTs are means for the transformation of the community itself as they are introduced in the economic, social, labor, family, personal and educational fields. Although the

  1. El EEES: una experiencia piloto en la uex

    Directory of Open Access Journals (Sweden)

    Guerrero, M.M.

    2006-01-01

    Full Text Available El proceso de Convergencia Europea en la Educación superior y la creciente importancia que en los últimos años está teniendo la evaluación de la calidad de la docencia suponen nuevas exigencias en nuestra planificación docente. Los cambios que todo este proceso implicarán serán importantes y numerosos, y para llevarlos a buen término es necesario que vengan acompañados por otros de índole metodológica que potencien el objetivo último de mejora de la calidad de la enseñanza universitaria. Ante esta situación y en nuestra parcela de los Métodos Cuantitativos, nos hemos planteado llevar a cabo “experiencias pilotos” en asignaturas como Estadística e Introducción a la Econometría y Matemáticas, dentro de la convocatoria de acciones para la adaptación de la UEX al EEES, que nos sirvan de referencia para el futuro próximo. En este trabajo presentamos los resultados obtenidos en el curso 2005/2006, en cuanto al trabajo del alumno, el nuestro como profesores, y las conclusiones a las que hemos llegado.

  2. Referéndum en Costa Rica: la primera experiencia

    Directory of Open Access Journals (Sweden)

    Max Alberto Esquivel Faerron

    2008-07-01

    Full Text Available El artículo aborda los distintos mecanismos de democracia directa regulados en el ordenamiento jurídico costarricense, profundizando en el instituto del referéndum. Se centra en analizar, con apoyo en datos estadísticos, la primera experiencia de la aplicación del referéndum en Costa Rica, relativo a la aprobación del Tratado de Libre Comercio entre República Dominicana, Centroamérica y Estados Unidos. Como parte de este estudio, el autor desarrolla, desde el punto de vista doctrinario y de derecho comparado, temas medulares del referéndum que fueron motivo de amplia discusión, tales como: el carácter excepcional de este instituto -contra poniéndolo con el listado de las solicitudes de recolección de firmas presentadas ante el Tribunal-, la fiscalización del proceso, la posición del Poder Ejecutivo a favor de una de las tesis en contienda, el financiamiento de las campañas propagandísticas, la información ciudadana sobre el tema de la consulta y la participación de los medios de comunicación.

  3. Long-circulating PEGylated manganese ferrite nanoparticles for MRI-based molecular imaging

    Science.gov (United States)

    Pernia Leal, Manuel; Rivera-Fernández, Sara; Franco, Jaime M.; Pozo, David; de La Fuente, Jesús M.; García-Martín, María Luisa

    2015-01-01

    Magnetic resonance based molecular imaging has emerged as a very promising technique for early detection and treatment of a wide variety of diseases, including cancer, neurodegenerative disorders, and vascular diseases. The limited sensitivity and specificity of conventional MRI are being overcome by the development of a new generation of contrast agents, using nanotechnology approaches, with improved magnetic and biological properties. In particular, for molecular imaging, high specificity, high sensitivity, and long blood circulation times are required. Furthermore, the lack of toxicity and immunogenicity together with low-cost scalable production are also necessary to get them into the clinics. In this work, we describe a facile, robust and cost-effective ligand-exchange method to synthesize dual T1 and T2 MRI contrast agents with long circulation times. These contrast agents are based on manganese ferrite nanoparticles (MNPs) between 6 and 14 nm in size covered by a 3 kDa polyethylene glycol (PEG) shell that leads to a great stability in aqueous media with high crystallinity and magnetization values, thus retaining the magnetic properties of the uncovered MNPs. Moreover, the PEGylated MNPs have shown different relaxivities depending on their size and the magnetic field applied. Thus, the 6 nm PEGylated MNPs are characterized by a low r2/r1 ratio of 4.9 at 1.5 T, hence resulting in good dual T1 and T2 contrast agents under low magnetic fields, whereas the 14 nm MNPs behave as excellent T2 contrast agents under high magnetic fields (r2 = 335.6 mM-1 s-1). The polymer core shell of the PEGylated MNPs minimizes their cytotoxicity, and allows long blood circulation times. This combination of cellular compatibility and excellent T2 and r2/r1 values under low magnetic fields, together with long circulation times, make these nanomaterials very promising contrast agents for molecular imaging.Magnetic resonance based molecular imaging has emerged as a very promising

  4. Synthesis and characterization of sugar based low molecular weight gelators and the preparation of chiral sulfinamides

    Science.gov (United States)

    Mangunuru, Hari Prasad Reddy

    Low molecular weight gelators (LMWGs) have received considerable attention in the field of chemistry from last few decades. These compounds form self-assembled fibrous networks like micelles, cylindrical, sheets, fibers, layers and so on. The fibrous network entraps the solvent and forms gel, because of the self-assembly phenomenon and their demonstrated potential uses in a variety of areas, ranging from environmental to medicinal applications. Sugars are good starting materials to synthesize the new class of LMWG's, because these are different from some expensive materials, these are natural products. We have synthesized and characterized the LMGS's based on D-glucose and D-glucosamine. D-glucosamine is the versatile starting material to make different peptoids and triazoles. Several series of compounds were synthesized using compounds 1-3 as starting material and studied the gelation behavior all the compounds. We have studied the self-assembling properties of a new class of tripeptoids, synthesized by one-pot Ugi reaction from simple starting materials. Among the focused library of tripeptoids synthesized, we found that several efficient low molecular weight organogelators were obtained for aqueous DMSO and ethanol mixtures. We have also synthesized and characterized a series of monosaccharide triazole derivatives. These compounds were synthesized from N-acetyl glucosamine and D-glucose via a Cu(I) catalyzed azide/alkyne cycloaddition reaction (CuAAc). The compounds have been screened for their gelation properties and several efficient low molecular weight organo/hydro gelators were obtained, among these compounds, five per-acetyl glucosamine derivatives and one peracetyl glucose derivative were able to form gels in water. These new molecules are expected to be useful in drug delivery and tissue engineering.*. Asymmetric synthesis of chiral amines is a challenging in synthetic organic chemistry. The development of new catalysts for asymmetric organic

  5. Molecularly imprinted polymerization-based surface plasmon resonance sensing for glucose detection in human urine

    Science.gov (United States)

    Banerji, Soame; Peng, Wei; Kim, Yoon-Chang; Booksh, Karl S.

    2006-10-01

    A novel Surface Plasmon Resonance (SPR) sensor to detect glucose using molecularly imprinted polymer (MIP) will be presented in this paper. SPR has been traditionally used as a probe for surface interaction of large molecules but harder to measure small molecules since the effective change in the SPR condition becomes smaller. The accurate measurement of glucose in complex physiological fluids like urine is particularly challenging since the constituents of these fluids vary significantly from person to person and even throughout the day for a particular individual. The polymer was prepared by crosslinking polyallyamine in the presence of Glucose Phosphate, monobarium salt (GPS-Ba) and attached to a 50 nm thin film of gold which had been sputtered on top of a glass slide, via amide coupling. Upon removal of the template, this sensor was used to detect glucose in human urine in physiologically significant levels (1-20 mg/ml). Enhancement of the glucose sensor was made possible by incorporating gold nanoparticles which improved the signal. This study has demonstrated the specific detection of glucose in a complex physiological fluid using SPR spectroscopy. The association of glucose to the imprinted polymer results in the swelling of the polymer that can be tracked by the minima in SPR spectra. The sensitivity of this method, while lower than protein based detection schemes, is sufficient for quantitative measurement of glucose in urine at physiologically significant levels without extensive pre-treatment of the sample. Given the nature of the weak non-covalent binding of glucose to the amine functional groups, the scheme used here can be adapted to detect a number of different molecular species of sizes comparable to that of glucose without the need for extensive sample preparation or use of chemicals with limited shelf life.

  6. A general SNP-based molecular barcode for Plasmodium falciparum identification and tracking

    Directory of Open Access Journals (Sweden)

    Rosen David

    2008-10-01

    Full Text Available Abstract Background Single nucleotide polymorphism (SNP genotyping provides the means to develop a practical, rapid, inexpensive assay that will uniquely identify any Plasmodium falciparum parasite using a small amount of DNA. Such an assay could be used to distinguish recrudescence from re-infection in drug trials, to monitor the frequency and distribution of specific parasites in a patient population undergoing drug treatment or vaccine challenge, or for tracking samples and determining purity of isolates in the laboratory during culture adaptation and sub-cloning, as well as routine passage. Methods A panel of twenty-four SNP markers has been identified that exhibit a high minor allele frequency (average MAF > 35%, for which robust TaqMan genotyping assays were constructed. All SNPs were identified through whole genome sequencing and MAF was estimated through Affymetrix array-based genotyping of a worldwide collection of parasites. These assays create a "molecular barcode" to uniquely identify a parasite genome. Results Using 24 such markers no two parasites known to be of independent origin have yet been found to have the same allele signature. The TaqMan genotyping assays can be performed on a variety of samples including cultured parasites, frozen whole blood, or whole blood spotted onto filter paper with a success rate > 99%. Less than 5 ng of parasite DNA is needed to complete a panel of 24 markers. The ability of this SNP panel to detect and identify parasites was compared to the standard molecular methods, MSP-1 and MSP-2 typing. Conclusion This work provides a facile field-deployable genotyping tool that can be used without special skills with standard lab equipment, and at reasonable cost that will unambiguously identify and track P. falciparum parasites both from patient samples and in the laboratory.

  7. Theragnosis-based combined cancer therapy using doxorubicin-conjugated microRNA-221 molecular beacon.

    Science.gov (United States)

    Lee, Jonghwan; Choi, Kyung-Ju; Moon, Sung Ung; Kim, Soonhag

    2016-01-01

    Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs. PMID:26454049

  8. Genotoxicity and molecular response of silver nanoparticle (NP-based hydrogel

    Directory of Open Access Journals (Sweden)

    Xu Liming

    2012-05-01

    Full Text Available Abstract Background Since silver-nanoparticles (NPs possess an antibacterial activity, they were commonly used in medical products and devices, food storage materials, cosmetics, various health care products, and industrial products. Various silver-NP based medical devices are available for clinical uses, such as silver-NP based dressing and silver-NP based hydrogel (silver-NP-hydrogel for medical applications. Although the previous data have suggested silver-NPs induced toxicity in vivo and in vitro, there is lack information about the mechanisms of biological response and potential toxicity of silver-NP-hydrogel. Methods In this study, the genotoxicity of silver-NP-hydrogel was assayed using cytokinesis-block micronucleus (CBMN. The molecular response was studied using DNA microarray and GO pathway analysis. Results and discussion The results of global gene expression analysis in HeLa cells showed that thousands of genes were up- or down-regulated at 48 h of silver-NP-hydrogel exposure. Further GO pathway analysis suggested that fourteen theoretical activating signaling pathways were attributed to up-regulated genes; and three signal pathways were attributed to down-regulated genes. It was discussed that the cells protect themselves against silver NP-mediated toxicity through up-regulating metallothionein genes and anti-oxidative stress genes. The changes in DNA damage, apoptosis and mitosis pathway were closely related to silver-NP-induced cytotoxicity and chromosome damage. The down-regulation of CDC14A via mitosis pathway might play a role in potential genotoxicity induced by silver-NPs. Conclusions The silver-NP-hydrogel induced micronuclei formation in cellular level and broad spectrum molecular responses in gene expression level. The results of signal pathway analysis suggested that the balances between anti-ROS response and DNA damage, chromosome instability, mitosis inhibition might play important roles in silver-NP induced toxicity

  9. Tuning the properties of copper-based catalysts based on molecular in situ studies of model systems.

    Science.gov (United States)

    Stacchiola, Darío J

    2015-07-21

    Studying catalytic processes at the molecular level is extremely challenging, due to the structural and chemical complexity of the materials used as catalysts and the presence of reactants and products in the reactor's environment. The most common materials used on catalysts are transition metals and their oxides. The importance of multifunctional active sites at metal/oxide interfaces has been long recognized, but a molecular picture of them based on experimental observations is only recently emerging. The initial approach to interrogate the surface chemistry of catalysts at the molecular level consisted of studying metal single crystals as models for reactive metal centers, moving later to single crystal or well-defined thin film oxides. The natural next iteration consisted in the deposition of metal nanoparticles on well-defined oxide substrates. Metal nanoparticles contain undercoordinated sites, which are more reactive. It is also possible to create architectures where oxide nanoparticles are deposited on top of metal single crystals, denominated inverse catalysts, leading in this case to a high concentration of reactive cationic sites in direct contact with the underlying fully coordinated metal atoms. Using a second oxide as a support (host), a multifunctional configuration can be built in which both metal and oxide nanoparticles are located in close proximity. Our recent studies on copper-based catalysts are presented here as an example of the application of these complementary model systems, starting from the creation of undercoordinated sites on Cu(111) and Cu2O(111) surfaces, continuing with the formation of mixed-metal copper oxides, the synthesis of ceria nanoparticles on Cu(111) and the codeposition of Cu and ceria nanoparticles on TiO2(110). Catalysts have traditionally been characterized before or after reactions and analyzed based on static representations of surface structures. It is shown here how dynamic changes on a catalyst's chemical state

  10. The evidence base for the use of internal dosimetry in the clinical practice of molecular radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Strigari, Lidia [Regina Elena National Cancer Institute, Laboratory of Medical Physics and Expert Systems, Rome (Italy); Konijnenberg, Mark [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Chiesa, Carlo [Instituto Nazionale Tumori, Department of Nuclear Medicine, Milan (Italy); Bardies, Manuel [UMR 1037 INSERM / Universite Paul Sabatier, Centre de Recherche en Cancerologie de Toulouse, Toulouse (France); Du, Yong [Royal Marsden NHS Foundation Trust, Department of Nuclear Medicine and PET/CT, Sutton, London (United Kingdom); Gleisner, Katarina Sjoegreen [Medical Radiation Physics, Clinical Sciences, Lund (Sweden); Lassmann, Michael [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Flux, Glenn [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Joint Department of Physics, Sutton (United Kingdom)

    2014-10-15

    Molecular radiotherapy (MRT) has demonstrated unique therapeutic advantages in the treatment of an increasing number of cancers. As with other treatment modalities, there is related toxicity to a number of organs at risk. Despite the large number of clinical trials over the past several decades, considerable uncertainties still remain regarding the optimization of this therapeutic approach and one of the vital issues to be answered is whether an absorbed radiation dose-response exists that could be used to guide personalized treatment. There are only limited and sporadic data investigating MRT dosimetry. The determination of dose-effect relationships for MRT has yet to be the explicit aim of a clinical trial. The aim of this article was to collate and discuss the available evidence for an absorbed radiation dose-effect relationships in MRT through a review of published data. Based on a PubMed search, 92 papers were found. Out of 79 studies investigating dosimetry, an absorbed dose-effect correlation was found in 48. The application of radiobiological modelling to clinical data is of increasing importance and the limited published data on absorbed dose-effect relationships based on these models are also reviewed. Based on National Cancer Institute guideline definition, the studies had a moderate or low rate of clinical relevance due to the limited number of studies investigating overall survival and absorbed dose. Nevertheless, the evidence strongly implies a correlation between the absorbed doses delivered and the response and toxicity, indicating that dosimetry-based personalized treatments would improve outcome and increase survival. (orig.)

  11. The evidence base for the use of internal dosimetry in the clinical practice of molecular radiotherapy

    International Nuclear Information System (INIS)

    Molecular radiotherapy (MRT) has demonstrated unique therapeutic advantages in the treatment of an increasing number of cancers. As with other treatment modalities, there is related toxicity to a number of organs at risk. Despite the large number of clinical trials over the past several decades, considerable uncertainties still remain regarding the optimization of this therapeutic approach and one of the vital issues to be answered is whether an absorbed radiation dose-response exists that could be used to guide personalized treatment. There are only limited and sporadic data investigating MRT dosimetry. The determination of dose-effect relationships for MRT has yet to be the explicit aim of a clinical trial. The aim of this article was to collate and discuss the available evidence for an absorbed radiation dose-effect relationships in MRT through a review of published data. Based on a PubMed search, 92 papers were found. Out of 79 studies investigating dosimetry, an absorbed dose-effect correlation was found in 48. The application of radiobiological modelling to clinical data is of increasing importance and the limited published data on absorbed dose-effect relationships based on these models are also reviewed. Based on National Cancer Institute guideline definition, the studies had a moderate or low rate of clinical relevance due to the limited number of studies investigating overall survival and absorbed dose. Nevertheless, the evidence strongly implies a correlation between the absorbed doses delivered and the response and toxicity, indicating that dosimetry-based personalized treatments would improve outcome and increase survival. (orig.)

  12. A bayesian mixed regression based prediction of quantitative traits from molecular marker and gene expression data.

    Directory of Open Access Journals (Sweden)

    Madhuchhanda Bhattacharjee

    Full Text Available Both molecular marker and gene expression data were considered alone as well as jointly to serve as additive predictors for two pathogen-activity-phenotypes in real recombinant inbred lines of soybean. For unobserved phenotype prediction, we used a bayesian hierarchical regression modeling, where the number of possible predictors in the model was controlled by different selection strategies tested. Our initial findings were submitted for DREAM5 (the 5th Dialogue on Reverse Engineering Assessment and Methods challenge and were judged to be the best in sub-challenge B3 wherein both functional genomic and genetic data were used to predict the phenotypes. In this work we further improve upon this previous work by considering various predictor selection strategies and cross-validation was used to measure accuracy of in-data and out-data predictions. The results from various model choices indicate that for this data use of both data types (namely functional genomic and genetic simultaneously improves out-data prediction accuracy. Adequate goodness-of-fit can be easily achieved with more complex models for both phenotypes, since the number of potential predictors is large and the sample size is not small. We also further studied gene-set enrichment (for continuous phenotype in the biological process in question and chromosomal enrichment of the gene set. The methodological contribution of this paper is in exploration of variable selection techniques to alleviate the problem of over-fitting. Different strategies based on the nature of covariates were explored and all methods were implemented under the bayesian hierarchical modeling framework with indicator-based covariate selection. All the models based in careful variable selection procedure were found to produce significant results based on permutation test.

  13. Effects of electronic coupling and electrostatic potential on charge transport in carbon-based molecular electronic junctions

    Science.gov (United States)

    2016-01-01

    Summary Molecular junctions consisting of 2–20 nm thick layers of organic oligomers oriented between a conducting carbon substrate and a carbon/gold top contact have proven to be reproducible and reliable, and will soon enter commercial production in audio processing circuits. The covalent, conjugated bond between one or both sp2-hybridized carbon contacts and an aromatic molecular layer is distinct from the more common metal/molecule or silicon/molecule structures in many reported molecular junctions. Theoretical observations based on density functional theory are presented here, which model carbon-based molecular junctions as single molecules and oligomers between fragments of graphene. Electronic coupling between the molecules and the contacts is demonstrated by the formation of hybrid orbitals in the model structure, which have significant electron density on both the graphene and the molecule. The energies of such hybrid orbitals correlate with tunneling barriers determined experimentally, and electronic coupling between the two graphene fragments in the model correlates with experimentally observed attenuation of transport with molecular layer thickness. Electronic coupling is affected significantly by the dihedral angle between the planes of the graphene and the molecular π-systems, but is absent only when the two planes are orthogonal. Coupling also results in partial charge transfer between the graphene contacts and the molecular layer, which results in a shift in electrostatic potential which affects the observed tunneling barrier. Although the degree of partial charge transfer is difficult to calculate accurately, it does provide a basis for the “vacuum level shift” observed in many experiments, including transport and ultraviolet photoelectron spectroscopy of molecular layers on conductors. PMID:26925350

  14. Effects of electronic coupling and electrostatic potential on charge transport in carbon-based molecular electronic junctions

    Directory of Open Access Journals (Sweden)

    Richard L. McCreery

    2016-01-01

    Full Text Available Molecular junctions consisting of 2–20 nm thick layers of organic oligomers oriented between a conducting carbon substrate and a carbon/gold top contact have proven to be reproducible and reliable, and will soon enter commercial production in audio processing circuits. The covalent, conjugated bond between one or both sp2-hybridized carbon contacts and an aromatic molecular layer is distinct from the more common metal/molecule or silicon/molecule structures in many reported molecular junctions. Theoretical observations based on density functional theory are presented here, which model carbon-based molecular junctions as single molecules and oligomers between fragments of graphene. Electronic coupling between the molecules and the contacts is demonstrated by the formation of hybrid orbitals in the model structure, which have significant electron density on both the graphene and the molecule. The energies of such hybrid orbitals correlate with tunneling barriers determined experimentally, and electronic coupling between the two graphene fragments in the model correlates with experimentally observed attenuation of transport with molecular layer thickness. Electronic coupling is affected significantly by the dihedral angle between the planes of the graphene and the molecular π-systems, but is absent only when the two planes are orthogonal. Coupling also results in partial charge transfer between the graphene contacts and the molecular layer, which results in a shift in electrostatic potential which affects the observed tunneling barrier. Although the degree of partial charge transfer is difficult to calculate accurately, it does provide a basis for the “vacuum level shift” observed in many experiments, including transport and ultraviolet photoelectron spectroscopy of molecular layers on conductors.

  15. Network analysis shows novel molecular mechanisms of action for copper-based chemotherapy

    Directory of Open Access Journals (Sweden)

    Jesús eEspinal-Enríquez

    2016-01-01

    Full Text Available The understanding of the mechanisms associated with the action of chemotherapeutic agents is fundamental to assess and account for possible side-effects of such treatments. Casiope'inas have demonstrated a cytotoxic effect by activation of pro-apoptotic processes in malignant cells. Such processes have been proved to activate the apoptotic intrinsic route, as well as cell cycle arrest. Despite this knowledge, the whole mechanism of action of Casiope'inas is yet to be completely understood. In this work, we implement a systems biology approach based on two pathway analysis tools (Over-Representation Analysis and Causal Network Analysis, to observe changes in some hallmarks of cancer, induced by this copper-based chemotherapeutic agent in HeLa cell lines. We find that the metabolism of metal ions is exacerbated, as well as cell division processes being globally diminished. We also show that cellular migration and proliferation events are decreased. Moreover, the molecular mechanisms of liver protection are increased in the cell cultures under the actions of Casiope'inas, unlike the case in many other cytotoxic drugs. We argue that this chemotherapeutic agent may be promising, given its protective hepatic function, concomitant with its cytotoxic participation in the onset of apoptotic processes in malignant cells.

  16. Photoisomerization dynamics of a rhodopsin-based molecule (potential molecular switch) with high quantum yields

    Science.gov (United States)

    Allen, Roland; Jiang, Chen-Wei; Zhang, Xiu-Xing; Fang, Ai-Ping; Li, Hong-Rong; Xie, Rui-Hua; Li, Fu-Li

    2015-03-01

    It is worthwhile to explore the detailed reaction dynamics of various candidates for molecular switches, in order to understand, e.g., the differences in quantum yields and switching times. Here we report density-functional-based simulations for the rhodopsin-based molecule 4-[4-Methylbenzylidene]-5-p-tolyl-3,4-dihydro-2H-pyrrole (MDP), synthesized by Sampedro et al. We find that the photoisomerization quantum yields are remarkably high: 82% for cis-to-trans, and 68% for trans-to-cis. The lifetimes of the S1 excited state in cis-MDP in our calculations are in the range of 900-1800 fs, with a mean value of 1270 fs, while the range of times required for full cis-to-trans isomerization are 1100-2000 fs, with a mean value of 1530 fs. In trans-MDP, the calculated S1 excited state lifetimes are 860-2140 fs, with a mean value of 1330 fs, and with the full trans-to-cis isomerization completed about 200 fs later. In both cases, the dominant reaction mechanism is rotation around the central C =C bond (connected to the pyrroline ring), and de-excitation occurs at an avoided crossing between the ground state and the lowest singlet state, near the midpoint of the rotational pathway. Research Fund for the Doctoral Program of Higher Education of China; Fundamental Research Funds for the Central Universities; Robert A. Welch Foundation; National Natural Science Foundation of China.

  17. Molecular phylogeny of western Atlantic Farfantepenaeus and Litopenaeus shrimp based on mitochondrial 16S partial sequences.

    Science.gov (United States)

    Maggioni, R; Rogers, A D; Maclean, N; D'Incao, F

    2001-01-01

    Partial sequences for the 16S rRNA mitochondrial gene were obtained from 10 penaeid shrimp species: Farfantepenaeus paulensis, F. brasiliensis, F. subtilis, F. duorarum, F. aztecus, Litopenaeus schmitti, L. setiferus, and Xiphopenaeus kroyeri from the western Atlantic and L. vannamei and L. stylirostris from the eastern Pacific. Sequences were also obtained from an undescribed morphotype of pink shrimp (morphotype II) usually identified as F. subtilis. The phylogeny resulting from the 16S partial sequences showed that these species form two well-supported monophyletic clades consistent with the two genera proposed in a recent systematic review of the suborder Dendrobranchiata. This contrasted with conclusions drawn from recent molecular phylogenetic work on penaeid shrimps based on partial sequences of the mitochondrial COI region that failed to support recent revisions of the Dendrobranchiata based on morphological analysis. Consistent differences observed in the sequences for morphotype II, coupled with previous allozyme data, support the conclusion that this is a previously undescribed species of Farfantepenaeus. PMID:11161743

  18. Molecular simulation-based structural prediction of protein complexes in mass spectrometry: the human insulin dimer.

    Science.gov (United States)

    Li, Jinyu; Rossetti, Giulia; Dreyer, Jens; Raugei, Simone; Ippoliti, Emiliano; Lüscher, Bernhard; Carloni, Paolo

    2014-09-01

    Protein electrospray ionization (ESI) mass spectrometry (MS)-based techniques are widely used to provide insight into structural proteomics under the assumption that non-covalent protein complexes being transferred into the gas phase preserve basically the same intermolecular interactions as in solution. Here we investigate the applicability of this assumption by extending our previous structural prediction protocol for single proteins in ESI-MS to protein complexes. We apply our protocol to the human insulin dimer (hIns2) as a test case. Our calculations reproduce the main charge and the collision cross section (CCS) measured in ESI-MS experiments. Molecular dynamics simulations for 0.075 ms show that the complex maximizes intermolecular non-bonded interactions relative to the structure in water, without affecting the cross section. The overall gas-phase structure of hIns2 does exhibit differences with the one in aqueous solution, not inferable from a comparison with calculated CCS. Hence, care should be exerted when interpreting ESI-MS proteomics data based solely on NMR and/or X-ray structural information. PMID:25210764

  19. Molecular simulation-based structural prediction of protein complexes in mass spectrometry: the human insulin dimer.

    Directory of Open Access Journals (Sweden)

    Jinyu Li

    2014-09-01

    Full Text Available Protein electrospray ionization (ESI mass spectrometry (MS-based techniques are widely used to provide insight into structural proteomics under the assumption that non-covalent protein complexes being transferred into the gas phase preserve basically the same intermolecular interactions as in solution. Here we investigate the applicability of this assumption by extending our previous structural prediction protocol for single proteins in ESI-MS to protein complexes. We apply our protocol to the human insulin dimer (hIns2 as a test case. Our calculations reproduce the main charge and the collision cross section (CCS measured in ESI-MS experiments. Molecular dynamics simulations for 0.075 ms show that the complex maximizes intermolecular non-bonded interactions relative to the structure in water, without affecting the cross section. The overall gas-phase structure of hIns2 does exhibit differences with the one in aqueous solution, not inferable from a comparison with calculated CCS. Hence, care should be exerted when interpreting ESI-MS proteomics data based solely on NMR and/or X-ray structural information.

  20. The semantic metadatabase (SEMEDA): ontology based integration of federated molecular biological data sources.

    Science.gov (United States)

    Köhler, Jacob; Schulze-Kremer, Steffen

    2002-01-01

    A system for "intelligent" semantic integration and querying of federated databases is being implemented by using three main components: A component which enables SQL access to integrated databases by database federation (MARGBench), an ontology based semantic metadatabase (SEMEDA) and an ontology based query interface (SEMEDA-query). In this publication we explain and demonstrate the principles, architecture and the use of SEMEDA. Since SEMEDA is implemented as 3 tiered web application database providers can enter all relevant semantic and technical information about their databases by themselves via a web browser. SEMEDA' s collaborative ontology editing feature is not restricted to database integration, and might also be useful for ongoing ontology developments, such as the "Gene Ontology" [2]. SEMEDA can be found at http://www-bm.cs.uni-magdeburg.de/semeda/. We explain how this ontologically structured information can be used for semantic database integration. In addition, requirements to ontologies for molecular biological database integration are discussed and relevant existing ontologies are evaluated. We further discuss how ontologies and structured knowledge sources can be used in SEMEDA and whether they can be merged supplemented or updated to meet the requirements for semantic database integration. PMID:12542408

  1. A Buffered Alcohol-Based Fixative for Histomorphologic and Molecular Applications.

    Science.gov (United States)

    Perry, Candice; Chung, Joon-Yong; Ylaya, Kris; Choi, Chel Hun; Simpson, Amari; Matsumoto, Kaipo T; Smith, William A; Hewitt, Stephen M

    2016-07-01

    Formalin-fixed paraffin-embedded (FFPE) tissue is the predominant preparation for diagnostic histopathological evaluation and increasingly the biospecimen on which molecular diagnostics are performed. However, formalin is carcinogenic and results in cross-linking of proteins and nicking and alterations of nucleic acids. Alternative fixatives, including 70% ethanol, improved biomolecular integrity; however, they have yet to replace neutral-buffered formalin (NBF). Herein, we describe the phosphate-buffered ethanol 70% (BE70) fixative. The histomorphology of BE70-fixed tissue is very similar to that of NBF; however, it is a non-cross-linking fixative and lacks the carcinogenic profile of formaldehyde-based fixatives. RNA isolated from tissue fixed in BE70 was of substantially higher quality and quantity than that was recovered from formalin-fixed tissue. Furthermore, the BE70 fixative showed excellent RNA and DNA integrity compared with that of NBF fixative based on real-time polymerase chain reaction analysis results. Immunohistochemical staining was similar for the antigen tested. In conclusion, BE70 is a non-cross-linking fixative that is superior to NBF and 70% ethanol with reference to biomolecule recovery and quality from paraffin-embedded tissue. Additional studies to compare the histomorphologic and immunohistochemical performance and utility in a clinical setting are required. PMID:27221702

  2. CCSD(T)/CBS fragment-based calculations of lattice energy of molecular crystals.

    Science.gov (United States)

    Červinka, Ctirad; Fulem, Michal; Růžička, Květoslav

    2016-02-14

    A comparative study of the lattice energy calculations for a data set of 25 molecular crystals is performed using an additive scheme based on the individual energies of up to four-body interactions calculated using the coupled clusters with iterative treatment of single and double excitations and perturbative triples correction (CCSD(T)) with an estimated complete basis set (CBS) description. The CCSD(T)/CBS values on lattice energies are used to estimate sublimation enthalpies which are compared with critically assessed and thermodynamically consistent experimental values. The average absolute percentage deviation of calculated sublimation enthalpies from experimental values amounts to 13% (corresponding to 4.8 kJ mol(-1) on absolute scale) with unbiased distribution of positive to negative deviations. As pair interaction energies present a dominant contribution to the lattice energy and CCSD(T)/CBS calculations still remain computationally costly, benchmark calculations of pair interaction energies defined by crystal parameters involving 17 levels of theory, including recently developed methods with local and explicit treatment of electronic correlation, such as LCC and LCC-F12, are also presented. Locally and explicitly correlated methods are found to be computationally effective and reliable methods enabling the application of fragment-based methods for larger systems. PMID:26874495

  3. CCSD(T)/CBS fragment-based calculations of lattice energy of molecular crystals

    Science.gov (United States)

    Červinka, Ctirad; Fulem, Michal; Růžička, Květoslav

    2016-02-01

    A comparative study of the lattice energy calculations for a data set of 25 molecular crystals is performed using an additive scheme based on the individual energies of up to four-body interactions calculated using the coupled clusters with iterative treatment of single and double excitations and perturbative triples correction (CCSD(T)) with an estimated complete basis set (CBS) description. The CCSD(T)/CBS values on lattice energies are used to estimate sublimation enthalpies which are compared with critically assessed and thermodynamically consistent experimental values. The average absolute percentage deviation of calculated sublimation enthalpies from experimental values amounts to 13% (corresponding to 4.8 kJ mol-1 on absolute scale) with unbiased distribution of positive to negative deviations. As pair interaction energies present a dominant contribution to the lattice energy and CCSD(T)/CBS calculations still remain computationally costly, benchmark calculations of pair interaction energies defined by crystal parameters involving 17 levels of theory, including recently developed methods with local and explicit treatment of electronic correlation, such as LCC and LCC-F12, are also presented. Locally and explicitly correlated methods are found to be computationally effective and reliable methods enabling the application of fragment-based methods for larger systems.

  4. Piperprotrusum (Piperaceae), a new species from southern Thailand based on morphological and molecular evidence

    Institute of Scientific and Technical Information of China (English)

    Runglawan SUDMOON; Tawatchai TANEE; Arunrat CHAVEERACH

    2011-01-01

    Piper protrusum Chaveer.& Tanee,sp.nov.is described and illustrated.It dominantly comprises three branching types with three different types of leaf blades,bases,and apexes.The critical distinguishing character is the protruded receptacle having a bract and nine stamens.Individual plants have been discovered in areas of Southern Thailand since 2004 without reproductive parts.The investigated sites were revisited several times,and an individual with flowers was finally found in July 2009.Phylogenetic analysis of the new species and five similar species is carried out based on DNA figerpfinting.The genetic distances between the new species and five similar species range from 0.25 to 0.35,supporting new species designation.Molecular data conform to morphological data in validating that it is a new species.Additionally,its DNA barcodes have been provided for further identification in case the morphological data is unclear.The sequence data have been submitted to the GenBank database under accession numbers GU980898 (rpoB gene),GU980899 (rpoC1 gene),and GU980900 (psbA-trnH region).

  5. Molecular Dynamics Study of Stability and Diffusion of Graphene-Based Drug Delivery Systems

    Directory of Open Access Journals (Sweden)

    Xiunan Wang

    2015-01-01

    Full Text Available Graphene, a two-dimensional nanomaterial with unique biomedical properties, has attracted great attention due to its potential applications in graphene-based drug delivery systems (DDS. In this work graphene sheets with various sizes and graphene oxide functionalized with polyethylene glycol (GO-PEG are utilized as nanocarriers to load anticancer drug molecules including CE6, DOX, MTX, and SN38. We carried out molecular dynamics calculations to explore the energetic stabilities and diffusion behaviors of the complex systems with focuses on the effects of the sizes and functionalization of graphene sheets as well as the number and types of drug molecules. Our study shows that the binding of graphene-drug complex is favorable when the drug molecules and finite graphene sheets become comparable in sizes. The boundaries of finite sized graphene sheets restrict the movement of drug molecules. The double-side loading often slows down the diffusion of drug molecules compared with the single-side loading. The drug molecules bind more strongly with GO-PEG than with pristine graphene sheets, demonstrating the advantages of functionalization in improving the stability and biocompatibility of graphene-based DDS.

  6. Cleavable Molecular Beacon for Hg(2+) Detection Based on Phosphorothioate RNA Modifications.

    Science.gov (United States)

    Huang, Po-Jung Jimmy; Wang, Feng; Liu, Juewen

    2015-07-01

    Mercury is a highly toxic heavy metal, and detection of Hg(2+) by biosensors has attracted extensive research interest in the past decade. In particular, a number of DNA-based sensing strategies have been developed. Well-known examples include thymine-Hg(2+) interactions and Hg(2+)-activated DNAzymes. However, these mechanisms are highly dependent on buffer conditions or require hybridization with another DNA strand. Herein, we report a new mechanism based on Hg(2+)-induced cleavage of phosphorothioate (PS) modified RNA. Among the various metal ions tested, Hg(2+) induced the most significant cleavage (∼16%), while other metals cleaved less than 2% of the same substrate. The uncleaved substrate undergoes desulfurization in the presence of Hg(2+). This cleavage reaction yields a similar amount of product from pH 3.5 to 7 and in the temperature range between 20 and 90 °C. Various PS RNA junctions can be cleaved with a similar efficiency, but PS DNA junctions cannot be cleaved. A molecular beacon containing three PS RNA modifications is designed, detecting Hg(2+) down to 1.7 nM with excellent selectivity. This sensor can also detect Hg(2+) in the Lake Ontario water sample, although its response is significantly masked by fish tissues. PMID:26060876

  7. Trichocyanines: a Red-Hair-Inspired Modular Platform for Dye-Based One-Time-Pad Molecular Cryptography

    OpenAIRE

    Leone, Loredana; Pezzella, Alessandro; Crescenzi, Orlando; Napolitano, Alessandra; Barone, Vincenzo; d’Ischia, Marco

    2015-01-01

    Current molecular cryptography (MoCryp) systems are almost exclusively based on DNA chemistry and reports of cryptography technologies based on other less complex chemical systems are lacking. We describe herein, as proof of concept, the prototype of the first asymmetric MoCryp system, based on an 8-compound set of a novel bioinspired class of cyanine-type dyes called trichocyanines. These novel acidichromic cyanine-type dyes inspired by red hair pigments were synthesized and characterized wi...

  8. Molecular pharmacognosy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This article analyzes the background and significance of molecular pharmacognosy,including the molecular identification of medicinal raw materials,phylogenetic evolution of medicinal plants and animals,evaluation and preservation of germplasm resources for medicinal plants and animals,etiology of endangerment and protection of endangered medicinal plants and animals,biosynthesis and bioregulation of active components in medicinal plants,and characteristics and the molecular bases of top-geoherbs.

  9. Molecular Dynamics Simulation of a Multi-Walled Carbon Nanotube Based Gear

    Science.gov (United States)

    Han, Jie; Globus, Al; Srivastava, Deepak; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We used molecular dynamics to investigate the properties of a multi-walled carbon nanotube based gear. Previous work computationally suggested that molecular gears fashioned from (14,0) single-walled carbon nanotubes operate well at 50-100 gigahertz. The gears were formed from nanotubes with teeth added via a benzyne reaction known to occur with C60. A modified, parallelized version of Brenner's potential was used to model interatomic forces within each molecule. A Leonard-Jones 6-12 potential was used for forces between molecules. The gear in this study was based on the smallest multi-walled nanotube supported by some experimental evidence. Each gear was a (52,0) nanotube surrounding a (37,10) nanotube with approximate 20.4 and 16,8 A radii respectively. These sizes were chosen to be consistent with inter-tube spacing observed by and were slightly larger than graphite inter-layer spacings. The benzyne teeth were attached via 2+4 cycloaddition to exterior of the (52,0) tube. 2+4 bonds were used rather than the 2+2 bonds observed by Hoke since 2+4 bonds are preferred by naphthalene and quantum calculations by Jaffe suggest that 2+4 bonds are preferred on carbon nanotubes of sufficient diameter. One gear was 'powered' by forcing the atoms near the end of the outside buckytube to rotate to simulate a motor. A second gear was allowed to rotate by keeping the atoms near the end of its outside buckytube on a cylinder. The ends of both gears were constrained to stay in an approximately constant position relative to each other, simulating a casing, to insure that the gear teeth meshed. The stiff meshing aromatic gear teeth transferred angular momentum from the powered gear to the driven gear. The simulation was performed in a vacuum and with a software thermostat. Preliminary results suggest that the powered gear had trouble turning the driven gear without slip. The larger radius and greater mass of these gears relative to the (14,0) gears previously studied requires a

  10. Molecular-imaging-based dose painting – a novel paradigm for radiation therapy prescription

    Science.gov (United States)

    Bentzen, Søren M.; Gregoire, Vincent

    2011-01-01

    Dose painting is the prescription of a non-uniform radiation dose distribution to the target volume based on functional or molecular images shown to be indicative of the local risk of relapse. Two prototypical strategies for implementing this novel paradigm in radiation oncology are reviewed: sub-volume boosting and dose painting by numbers. Sub-volume boosting involves the selection of a “target within the target”, defined by image segmentation on the basis of the quantitative information in the image or morphologically, and this is related to image based target volume selection and delineation. Dose painting by numbers is a voxel-level prescription of dose based on a mathematical transformation of the image intensity of individual pixels. Quantitative use of images to decide both where and how to delivery radiation therapy in an individual case is also called theragnostic imaging. Dose painting targets are imaging surrogates for cellular or microenvironmental phenotypes associated with poor radioresponsiveness. In this review, the focus is on positron emission tomography (PET) tracers: FDG and choline as surrogates for tumor burden, FLT as a surrogate for proliferation (or cellular growth fraction) and hypoxia sensitive tracers including FMISO, EF3, EF5 and Cu-ATSM as surrogates of cellular hypoxia. Research advances supporting the clinico-biological rationale for dose painting are reviewed as are studies of the technical feasibility of optimizing and delivering realistic dose painted radiation therapy plans. Challenges and research priorities in this exciting research field are defined and a possible design for a randomized clinical trial of dose painting is presented. PMID:21356478

  11. Ultra high molecular weight polyethylene as a base material for shielding cosmic radiation in aerospace applications

    International Nuclear Information System (INIS)

    Materials with high content of hydrogen have good properties of shielding against the effects of cosmic rays (CR) because are less effective than materials with high nuclear masses in the generation of secondary radiation. Beside the Aluminum, Polyethylene has been used as a reference and as a base material for composites applied in structures and in shielding of ionizing radiation for aerospace applications. Ultra high molecular weight polyethylene (UHMWPE), pure and doped 10% by mass with cadmium chloride, had its shielding properties for CR evaluated in this paper. Methodology used was based in conventional radioactive sources employed on simple geometries experiments and then computational simulation for isotropic fluxes of cosmic-ray high energy particles. Transmission experiments were performed with a3.7GBq (100 mCi)241Am-Be neutron source and a set of conventional calibration gamma radiation sources. Samples were characterized according to their gamma total attenuation coefficients from 59 to 1,408 keV, dose deposition curve for 60Co gamma-rays, fast neutron transmission coefficient, generation and self-absorption of thermal neutrons as well as their generation of internal cascades of secondary electrons and gamma-rays by nuclear interactions of fast neutrons with shielding material. Main effects of the additive in the polyethylene base were the most effective removal of gamma radiation and of secondary electrons with energies below 200 keV, the reduction of the albedo as well as the thermal neutrons transmission. Dose reduction due to primary CR were not significant, since the largest contribution to the doses due to high energy ionizing particles transmitted and, also, due to secondary radiation with energy above 1 MeV produced in shielding. (author)

  12. Ultra high molecular weight polyethylene as a base material for shielding cosmic radiation in aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marlon A., E-mail: marlon@ieav.cta.br [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Divisao de Fisica Aplicada; Goncalez, Odair L. [Instituto Tecnologico de Aeronautica (PG/CTE/ITA), Sao Jose dos Campos, SP (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnologias Espaciais

    2013-07-01

    Materials with high content of hydrogen have good properties of shielding against the effects of cosmic rays (CR) because are less effective than materials with high nuclear masses in the generation of secondary radiation. Beside the Aluminum, Polyethylene has been used as a reference and as a base material for composites applied in structures and in shielding of ionizing radiation for aerospace applications. Ultra high molecular weight polyethylene (UHMWPE), pure and doped 10% by mass with cadmium chloride, had its shielding properties for CR evaluated in this paper. Methodology used was based in conventional radioactive sources employed on simple geometries experiments and then computational simulation for isotropic fluxes of cosmic-ray high energy particles. Transmission experiments were performed with a3.7GBq (100 mCi){sup 241}Am-Be neutron source and a set of conventional calibration gamma radiation sources. Samples were characterized according to their gamma total attenuation coefficients from 59 to 1,408 keV, dose deposition curve for {sup 60}Co gamma-rays, fast neutron transmission coefficient, generation and self-absorption of thermal neutrons as well as their generation of internal cascades of secondary electrons and gamma-rays by nuclear interactions of fast neutrons with shielding material. Main effects of the additive in the polyethylene base were the most effective removal of gamma radiation and of secondary electrons with energies below 200 keV, the reduction of the albedo as well as the thermal neutrons transmission. Dose reduction due to primary CR were not significant, since the largest contribution to the doses due to high energy ionizing particles transmitted and, also, due to secondary radiation with energy above 1 MeV produced in shielding. (author)

  13. Structure-based inference of molecular functions of proteins of unknown function from Berkeley Structural Genomics Center

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung-Hou; Shin, Dong Hae; Hou, Jingtong; Chandonia, John-Marc; Das, Debanu; Choi, In-Geol; Kim, Rosalind; Kim, Sung-Hou

    2007-09-02

    Advances in sequence genomics have resulted in an accumulation of a huge number of protein sequences derived from genome sequences. However, the functions of a large portion of them cannot be inferred based on the current methods of sequence homology detection to proteins of known functions. Three-dimensional structure can have an important impact in providing inference of molecular function (physical and chemical function) of a protein of unknown function. Structural genomics centers worldwide have been determining many 3-D structures of the proteins of unknown functions, and possible molecular functions of them have been inferred based on their structures. Combined with bioinformatics and enzymatic assay tools, the successful acceleration of the process of protein structure determination through high throughput pipelines enables the rapid functional annotation of a large fraction of hypothetical proteins. We present a brief summary of the process we used at the Berkeley Structural Genomics Center to infer molecular functions of proteins of unknown function.

  14. Experiencia de podcasting en la enseñanza de una segunda lengua

    Directory of Open Access Journals (Sweden)

    Heidy Selene Robles Noriega

    2011-01-01

    Full Text Available Hoy en día el aprendizaje móvil está adquiriendo bastante auge en todas las áreas del conocimiento, en especial en el aprendizaje de una segunda lengua. El presente artículo tiene por objetivo describir los resultados de una experiencia piloto realizada con un grupo de estudiantes de primer semestre de Relaciones Internacionales en la asignatura de inglés, nivelatorio. La finalidad de esta experiencia es mejorar las habilidades auditivas apoyadas con aprendizaje móvil. Para ello, se implementaron archivos de audio llamados podcasts a través de dispositivos móviles. Se diseñaron siete podcasts teniendo en cuenta las necesidades y falencias de los estudiantes. Los resultados de esta experiencia fueron favorables.

  15. Cambiar paradigmas: una experiencia en educación superior

    Directory of Open Access Journals (Sweden)

    Gisella Vargas Chinchilla

    2004-09-01

    Full Text Available

    Resumen. Una experiencia en educación superior, al estilo de investigación-acción, donde una “comunidad de aprendizaje” constituida por docentes y estudiantes, busca convertirse en entes multiplicadores del desarrollo sostenible, dentro del plan de formación de docentes de Educación Preescolar.

    Esta investigación constituye el Trabajo final de Graduación, requisito de un grupo de estudiantes para obtener el grado de Licenciadas en Educación Preescolar, en la Universidad de Costa Rica. El proceso metodológico dio inicio con un diagnóstico, para seguir con un plan de acción, organizado y desarrollado en conjunto, estudiantes y docentes, para culminar con la aceptación de “compromisos ambientales” asumidos por las personas participantes.

     

    Abstract. This is a research-action type of experience in higher education lived by a “learning community” conformed by teachers and students whose aim is to become fostering agents for sustainable development. The experience was carried out as part of the plan for teacher training in Preschool Education.

    This paper is the authors' Final Graduation Paper, a requirement to obtain a Licentiate degree in Preschool Education at the University of Costa Rica. The research began with a diagnosis that would lead to the implementation of an action plan that was organized and carried out jointly by the students and their teachers. The project finished with the participants' acceptance of some “environmental commitments”.

  16. Una experiencia de conocimiento situado: la línea de Jóvenes y Culturas Juveniles del DIUC

    Directory of Open Access Journals (Sweden)

    José Fernando Serrano A.

    2009-04-01

    Full Text Available El artículo presenta una mirada retrospectiva a la línea de Investigación en Jóvenes y Culturas Juveniles del IESCO (DIUC entre 1998-2004. Para ello, se observan las preguntas de partida, los ejes de la reflexión y sus resultados. A lo largo del período observado se produce una pérdida de seguridad en la comprensión de los sujetos jóvenes desde lógicas descriptivas, y se pasa más bien a observar los procesos de subjetivación juvenil. Con base en ello, se caracteriza el conocimiento producido por la línea como una experiencia parcial, localizada, corporeizada y crítica de los estudios de juventud.

  17. The effect of molecular geometry on the photovoltaic property of diketopyrrolopyrrole based non-fullerene acceptors

    DEFF Research Database (Denmark)

    Zhang, Fei; Brandt, Rasmus Guldbæk; Gu, Zhuowei;

    2015-01-01

    , Ph(DPP)2 and PhDMe(DPP)2 with similar chemical components but different molecular geometries. Due to its more twisted molecular conformation, PhDMe(DPP)2 shows more blue-shifted absorption bands, higher electron mobility, and better miscibility with the polymer donor poly(3-hexylthiophene) (P3HT...

  18. Characterization-Based Molecular Design of Bio-Fuel Additives Using Chemometric and Property Clustering Techniques

    OpenAIRE

    Subin eHada; Charles Conrad Solvason; Mario Richard Eden

    2014-01-01

    In this work, multivariate characterization data such as infrared spectroscopy was used as a source of descriptor data involving information on molecular architecture for designing structured molecules with tailored properties. Application of multivariate statistical techniques such as principal component analysis allowed capturing important features of the molecular architecture from enormous amount of complex data to build appropriate latent variable models. Combining the property clusterin...

  19. Teaching the Process of Molecular Phylogeny and Systematics: A Multi-Part Inquiry-Based Exercise

    Science.gov (United States)

    Lents, Nathan H.; Cifuentes, Oscar E.; Carpi, Anthony

    2010-01-01

    Three approaches to molecular phylogenetics are demonstrated to biology students as they explore molecular data from "Homo sapiens" and four related primates. By analyzing DNA sequences, protein sequences, and chromosomal maps, students are repeatedly challenged to develop hypotheses regarding the ancestry of the five species. Although these…

  20. Molecular Gastronomy: A Food Fad or an Interface for Science-based Cooking?

    NARCIS (Netherlands)

    Linden, van der E.; McClements, D.J.; Ubbink, J.

    2008-01-01

    A review is given over the field of molecular gastronomy and its relation to science and cooking. We begin with a brief history of the field of molecular gastronomy, the definition of the term itself, and the current controversy surrounding this term. We then highlight the distinction between molecu

  1. Experiencias de vida en mujeres con cáncer de mama en quimioterapia*

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Parra Gómez

    2011-01-01

    Full Text Available Introducción: El cáncer de mama es una patología muy frecuente y los tratamientos como la quimioterapia afectan las experiencias de vida y el psiquismo de la mujer. Los estudios en que se trate de entender cómo la experiencia de la quimioterapia afecta la vida de las mujeres son escasos en Colombia. Objetivos: Entender las consecuencias del tratamiento con quimioterapia en las experiencias de vida de la mujer con cáncer en los aspectos personal y social, para mejorar los elementos psicoterapéuticos y las decisiones médicas Metodología: Se utilizó un método cualitativo-interpretativo con herramientas analíticas de la teoría fundamentada, teniendo como marco de referencia el modelo ecológico de Bronfrenbrenner. Resultados: Se desarrollaron las siguientes categorías de comprensión del fenómeno: 1 Experiencias de cambio en la corporalidad y reacciones emocionales; 2 significados del tratamiento, nuevas creencias y nuevos objetivos vitales; 3 experiencias con la familia y la comunidad, y 4 experiencias con otros pacientes y el equipo médico. Conclusiones: Este estudio muestra que la mujer sometida a tratamiento con quimioterapia tiene cambios en su psiquismo y sus relaciones interpersonales. Las mujeres terminan aceptando los cambios en su vida, pero admiten la necesidad de acompañamiento psicológico durante el proceso para evitar sufrimientos innecesarios.

  2. Studies of base pair sequence effects on DNA solvation based on all-atom molecular dynamics simulations

    Indian Academy of Sciences (India)

    Surjit B Dixit; Mihaly Mezei; David L Beveridge

    2012-07-01

    Detailed analyses of the sequence-dependent solvation and ion atmosphere of DNA are presented based on molecular dynamics (MD) simulations on all the 136 unique tetranucleotide steps obtained by the ABC consortium using the AMBER suite of programs. Significant sequence effects on solvation and ion localization were observed in these simulations. The results were compared to essentially all known experimental data on the subject. Proximity analysis was employed to highlight the sequence dependent differences in solvation and ion localization properties in the grooves of DNA. Comparison of the MD-calculated DNA structure with canonical A- and B-forms supports the idea that the G/C-rich sequences are closer to canonical A- than B-form structures, while the reverse is true for the poly A sequences, with the exception of the alternating ATAT sequence. Analysis of hydration density maps reveals that the flexibility of solute molecule has a significant effect on the nature of observed hydration. Energetic analysis of solute–solvent interactions based on proximity analysis of solvent reveals that the GC or CG base pairs interactmore strongly with watermolecules in the minor groove of DNA that the AT or TA base pairs, while the interactions of the AT or TA pairs in the major groove are stronger than those of the GC or CG pairs. Computation of solvent-accessible surface area of the nucleotide units in the simulated trajectories reveals that the similarity with results derived from analysis of a database of crystallographic structures is excellent. The MD trajectories tend to follow Manning’s counterion condensation theory, presenting a region of condensed counterions within a radius of about 17 Å from the DNA surface independent of sequence. The GC and CG pairs tend to associate with cations in the major groove of the DNA structure to a greater extent than the AT and TA pairs. Cation association is more frequent in the minor groove of AT than the GC pairs. In general

  3. Molecular tagging velocimetry based on photobleaching reaction for measuring liquid velocity and velocity gradients

    International Nuclear Information System (INIS)

    The local instantaneous velocity and velocity gradient are of great importance for understanding and modeling the momentum transfers and turbulence properties in the flows in nuclear power plants. Though many measurement methods are available for the velocity, there are few methods for measuring the velocity gradient directly. To measure the local instantaneous velocity and velocity gradient, a molecular tagging velocimetry based on photobleaching reaction is developed in this study. The photobleaching is an irreversible photodegradation of a fluorescent dye, and therefore the velocity and its gradient can be measured from the translation and deformation of photobleached tag, respectively. The most significant features of the developed method are as follows: (a) local instantaneous velocity and velocity gradients are measurable, (b) the measurement can be performed at arbitrary points in a flow field, and (c) tracer particles disturbing a flow are not required. The method was applied to a laminar pipe flow, laminar suction flow, flow around single drop and a turbulent flow in a square duct. It was confirmed that (1) the method can accurately measure radial distributions of liquid velocity and shear stress in the pipe flow, (2) local instantaneous velocity distributions around single drop are successfully measured, (3) the time evolution of velocity field is measurable by forming multiple tags in a matrix arrangement, and (4) the method is applicable to turbulent flows. (authors)

  4. Confirmation of a natural hybrid species in Petrocosmea (Gesneriaceae) based on molecular and morphological evidence

    Institute of Scientific and Technical Information of China (English)

    Zhi-Jing QIU; Zu-Li YUAN; Zhen-Yu LI; yin-Zheng WANG

    2011-01-01

    A natural hybrid species in Petrocosmea named Longianthera in Yanshan County,Yunnan Province is confirmed for the first time based on molecular and morphological evidence.The character count procedure of the variable characters show that Longianthera populations are characteristic of the intermediate morphological traits between its putative parents Yanshan and Petrocosmea martinii.The nuclear ribosomal internal transcribed spacer region and three chloroplast regions of matK,trnL-F,and trnT-L are sequenced in the putativehybrid and the related species.Both alignment of DNA sequences and the phylogenetic trees could exclude all the other species in Petrocosmea as the parental species except for Yanshan and P martinii.Eight haplotypes in the 31 internal transcribed spacer sequences and six haplotypes in 42 cpDNA sequences were found from 14 individuals of Longianthera populations.The analyses of DNA sequences,haplotypes,and phylogenetic trees indicate that Longianthera is likely a hybrid species between its putative parents Yanshan and P martinii,in which Yanshan might be the most possible maternal parent.Several factors may contribute to the natural hybridization between these two parental species in Petrocosmea,such as the overlapped geographic distribution,habitats,flowering periods,and shared pollinators.Finally,the new species of Yanshan and the natural hybrid species of Longianthera are described.

  5. Synthesis, anticancer activity and molecular docking study of Schiff base complexes containing thiazole moiety

    Directory of Open Access Journals (Sweden)

    Mokhles M. Abd-Elzaher

    2016-03-01

    Full Text Available A Schiff base ligand 1 was prepared from condensation of salicyaldehyde with 2-amino-4-phenyl-5-methyl thiazole. The ligand forms complexes with CoII, NiII, CuII, and ZnII in good yield. The synthesized compounds were characterized by elemental analysis, magnetic susceptibility, molar conductance, infrared spectra, 1H and 13C NMR, mass, electronic absorption and ESR spectroscopy. The anticancer activity of the synthesized compounds was studied against different human tumor cell lines: breast cancer MCF-7, liver cancer HepG2, lung carcinoma A549 and colorectal cancer HCT116 in comparison with the activity of doxorubicin as a reference drug. The study showed that ZnII complex showed potent inhibition against human TRK in the four cell lines (HepG2, MCF7, A549, HCT116 by the ratio 80, 70, 61 and 64% respectively as compared to the inhibition in the untreated cells. Moreover, the molecular docking into TRK (PDB: 1t46 was done for the optimization of the aforementioned compounds as potential TRK inhibitors.

  6. Molecular phylogenetic analysis of Indonesia Solanaceae based on DNA sequences of internal transcribed spacer region

    Science.gov (United States)

    Hidayat, Topik; Priyandoko, Didik; Islami, Dina Karina; Wardiny, Putri Yunitha

    2016-02-01

    Solanaceae is one of largest family in Angiosperm group with highly diverse in morphological character. In Indonesia, this group of plant is very popular due to its usefulness as food, ornamental and medicinal plants. However, investigation on phylogenetic relationship among the member of this family in Indonesia remains less attention. The purpose of this study was to evaluate the phylogenetics relationship of the family especially distributed in Indonesia. DNA sequences of Internal Transcribed Spacer (ITS) region of 19 species of Solanaceae and three species of outgroup, which belongs to family Convolvulaceae, Apocynaceae, and Plantaginaceae, were isolated, amplified, and sequenced. Phylogenetic tree analysis based on parsimony method was conducted with using data derived from the ITS-1, 5.8S, and ITS-2, separately, and the combination of all. Results indicated that the phylogenetic tree derived from the combined data established better pattern of relationship than separate data. Thus, three major groups were revealed. Group 1 consists of tribe Datureae, Cestreae, and Petunieae, whereas group 2 is member of tribe Physaleae. Group 3 belongs to tribe Solaneae. The use of the ITS region as a molecular markers, in general, support the global Solanaceae relationship that has been previously reported.

  7. Magnetotransport in MgO-based magnetic tunnel junctions grown by molecular beam epitaxy (invited)

    International Nuclear Information System (INIS)

    The strong impact of molecular beam epitaxy growth and Synchrotron Radiation characterization tools in the understanding of fundamental issues in nanomagnetism and spintronics is illustrated through the example of fully epitaxial MgO-based Magnetic Tunnel Junctions (MTJs). If ab initio calculations predict very high tunnel magnetoresistance (TMR) in such devices, some discrepancy between theory and experiments still exists. The influence of imperfections in real systems has thus to be considered like surface contaminations, structural defects, unexpected electronic states, etc. The influence of possible oxygen contamination at the Fe/MgO(001) interface is thus studied, and is shown to be not so detrimental to TMR as predicted by ab initio calculations. On the contrary, the decrease of dislocations density in the MgO barrier of MTJs using Fe1−xVx electrodes is shown to significantly increase TMR. Finally, unexpected transport properties in Fe1−XCox/MgO/Fe1−XCox (001) are presented. With the help of spin and symmetry resolved photoemission and ab initio calculation, the TMR decrease for Co content higher than 25% is shown to come from the existence of an interface state and the shift of the empty Δ1 minority spin state towards the Fermi level

  8. Molecular mechanisms associated with breast cancer based on integrated gene expression profiling by bioinformatics analysis.

    Science.gov (United States)

    Wu, Di; Han, Bing; Guo, Liang; Fan, Zhimin

    2016-07-01

    In this study, we aimed to gain more insights into the underlying molecular mechanisms responsible for breast cancer (BC) progression. Three gene expression profiles of human BC were integrated and used to screen the differentially expressed genes (DEGs) between healthy breast samples and BC samples. Protein-protein interaction (PPI) network of DEGs was constructed by mapping DEGs into the Search Tool for the Retrieval of Interacting Genes (STRING) database; then the subnetworks of PPI were constructed with plug-in, MCODE and DEGs in Subnetwork 1 were analysed based on Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway database ( http://www.genome.jp/kegg /). In addition, co-expression network of DEGs was established using the Cytoscape. Totalally 931 DEGs were selected, including 340 up-regulated genes and 591 down-regulated genes. KEGG pathway analysis for DEGs in Subnetwork 1 showed that the pathogenesis of BC was associated with cell cycle, oocyte meiosis, progesterone-mediated oocyte maturation and p53 signalling pathways. Meanwhile, the most significant-related DEGs were found by co-expression network analysis of DEGs. In conclusion, CCNG1 might be involved in the progression of BC via inhibiting cell proliferation, and ADAMTS1 might play a crucial role in BC development through the regulation of angiogenesis. PMID:26804550

  9. DVD technology-based molecular diagnosis platform: quantitative pregnancy test on a disc.

    Science.gov (United States)

    Li, Xiaochun; Weng, Samuel; Ge, Bixia; Yao, Zhihui; Yu, Hua-Zhong

    2014-05-21

    A diagnosis platform based entirely on DVD technology was developed for on-site quantitation of molecular analytes of interest, e.g., human chorionic gonadotropin (hCG) in urine samples ("quantitative pregnancy test on a disc"). An hCG-specific monoclonal antibody-binding assay prepared on a regular DVD-R was labeled with nanogold-streptavidin conjugates for signal enhancement with a customized silver-staining protocol. An unmodified, conventional computer optical drive was used for assay reading, and free disc-quality analysis software for data processing. The performance (sensitivity and selectivity) of this DVD assay is comparable to that of well-established colorimetric methods (determination of optical darkness ratios) and standard enzyme-linked immunosorbent assays (ELISA). As validated by examining its linear correlation with the ELISA results on the same set of samples, the DVD assay promises to be a low-cost, multiplex, point-of-care (POC) diagnostic tool for physicians and even for individuals at home, producing prompt results. PMID:24695902

  10. Elastic properties of amorphous boron suboxide based solids studied using ab initio molecular dynamics

    International Nuclear Information System (INIS)

    We have studied the correlation between chemical composition, structure, chemical bonding and elastic properties of amorphous B6O based solids using ab initio molecular dynamics. These solids are of different chemical compositions, but the elasticity data appear to be a function of density. This is in agreement with previous experimental observations. As the density increases from 1.64 to 2.38 g cm-3, the elastic modulus increases from 74 to 253 GPa. This may be understood by analyzing the cohesive energy and the chemical bonding of these compounds. The cohesive energy decreases from -7.051 to -7.584 eV/atom in the elastic modulus range studied. On the basis of the electron density distributions, Mulliken analysis and radial distribution functions, icosahedral bonding is the dominating bonding type. C and N promote cross-linking of icosahedra and thus increase the density, while H hinders the cross-linking by forming OH groups. The presence of icosahedral bonding is independent of the density

  11. Molecular analysis of dolphin morbillivirus: A new sensitive detection method based on nested RT-PCR.

    Science.gov (United States)

    Centelleghe, Cinzia; Beffagna, Giorgia; Zanetti, Rossella; Zappulli, Valentina; Di Guardo, Giovanni; Mazzariol, Sandro

    2016-09-01

    Cetacean Morbillivirus (CeMV) has been identified as the most pathogenic virus for cetaceans. Over the past three decades, this RNA virus has caused several outbreaks of lethal disease in odontocetes and mysticetes worldwide. Isolation and identification of CeMV RNA is very challenging in whales because of the poor preservation status frequently shown by tissues from stranded animals. Nested reverse transcription polymerase chain reaction (nested RT-PCR) is used instead of conventional RT-PCR when it is necessary to increase the sensitivity and the specificity of the reaction. This study describes a new nested RT-PCR technique useful to amplify small amounts of the cDNA copy of Cetacean morbillivirus (CeMV) when it is present in scant quantity in whales' biological specimens. This technique was used to analyze different tissues (lung, brain, spleen and other lymphoid tissues) from one under human care seal and seven cetaceans stranded along the Italian coastline between October 2011 and September 2015. A well-characterized, 200 base pair (bp) fragment of the dolphin Morbillivirus (DMV) haemagglutinin (H) gene, obtained by nested RT-PCR, was sequenced and used to confirm DMV positivity in all the eight marine mammals under study. In conclusion, this nested RT-PCR protocol can represent a sensitive detection method to identify CeMV-positive, poorly preserved tissue samples. Furthermore, this is also a rather inexpensive molecular technique, relatively easy to apply. PMID:27220282

  12. Electrospun Nanofibers from a Tricyanofuran-Based Molecular Switch for Colorimetric Recognition of Ammonia Gas.

    Science.gov (United States)

    Khattab, Tawfik A; Abdelmoez, Sherif; Klapötke, Thomas M

    2016-03-14

    A chromophore based on tricyanofuran (TCF) with a hydrazone (H) recognition moiety was developed. Its molecular-switching performance is reversible and has differential sensitivity towards aqueous ammonia at comparable concentrations. Nanofibers were fabricated from the TCF-H chromophore by electrospinning. The film fabricated from these nanofibers functions as a solid-state optical chemosensor for probing ammonia vapor. Recognition of ammonia vapor occurs by proton transfer from the hydrazone fragment of the chromophore to the ammonia nitrogen atom and is facilitated by the strongly electron withdrawing TCF fragment. The TCF-H chromophore was added to a solution of poly(acrylic acid), which was electrospun to obtain a nanofibrous sensor device. The morphology of the nanofibrous sensor was determined by SEM, which showed that nanofibers with a diameter range of 200-450 nm formed a nonwoven mat. The resultant nanofibrous sensor showed very good sensitivity in ammonia-vapor detection. Furthermore, very good reversibility and short response time were also observed. PMID:26864701

  13. Stearic acid based oleogels: a study on the molecular, thermal and mechanical properties.

    Science.gov (United States)

    Sagiri, S S; Singh, Vinay K; Pal, K; Banerjee, I; Basak, Piyali

    2015-03-01

    Stearic acid and its derivatives have been used as gelators in food and pharmaceutical gel formulations. However, the mechanism pertaining to the stearic acid based gelation has not been deciphered yet. Keeping that in mind, we investigated the role of stearic acid on physic-chemical properties of oleogel. For this purpose, two different oil (sesame oil and soy bean oil) formulations/oleogels were prepared. In depth analysis of gel kinetics, gel microstructure, molecular interactions, thermal and mechanical behaviors of the oleogels were done. The properties of the oleogels were dependent on the type of the vegetable oil used and the concentration of the stearic acid. Avrami analysis of DSC thermograms indicated that heterogeneous nucleation was coupled with the one-dimensional growth of gelator fibers as the key phenomenon in the formation of oleogels. Viscoelastic and pseudoplastic nature of the oleogels was analyzed in-depth by fitting the stress relaxation data in modified Peleg's model and rheological studies, respectively. Textural studies have revealed that the coexistence of hydrogen bond dissipation and formation of new bonds is possible under stress conditions in the physical oleogels. PMID:25579972

  14. Study of AFM-based nanometric cutting process using molecular dynamics

    International Nuclear Information System (INIS)

    Three-dimensional molecular dynamics (MD) simulations are conducted to investigate the atomic force microscope (AFM)-based nanometric cutting process of copper using diamond tool. The effects of tool geometry, cutting depth, cutting velocity and bulk temperature are studied. It is found that the tool geometry has a significant effect on the cutting resistance. The friction coefficient (cutting resistance) on the nanoscale decreases with the increase of tool angle as predicted by the macroscale theory. However, the friction coefficients on the nanoscale are bigger than those on the macroscale. The simulation results show that a bigger cutting depth results in more material deformation and larger chip volume, thus leading to bigger cutting force and bigger normal force. It is also observed that a higher cutting velocity results in a larger chip volume in front of the tool and bigger cutting force and normal force. The chip volume in front of the tool increases while the cutting force and normal force decrease with the increase of bulk temperature.

  15. Magnetic molecular imprint-based extraction of sulfonylurea herbicides and their determination by capillary liquid chromatography

    International Nuclear Information System (INIS)

    We have developed a simple method for the extraction of sulfonylurea herbicides (SUHs) from environmental water samples. It is based on a magnetic molecular imprint (MMIP) as a sorbent. The MMIP was prepared using metsulfuron-methyl as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the cross-linking agent, and magnetite as the magnetic component. Extraction can be carried out by blending and stirring water sample, extraction solvent and MMIP. Once the extraction is completed, the MMIP containing the SUHs can be separated from the sample matrix with a magnet. The SUHs desorbed from the polymers were then quantified by capillary liquid chromatography with diode array detection. The limits of quantification are in the range of 0.08 to 0.1 ng mL-1. Repeatabilities of peak areas and retention times range from 2.9 % to 4.0 % and from 0.1 % to 0.3 %, respectively. The method was successfully applied to the determination of the SUHs bensulfuron-methyl, metsulfuronmethyl, pyrazosulfuron-methyl, thifensulfuron-methyl, and triasulfuron in waste water samples. Recoveries range from 94.3 % to 102.3 %. (author)

  16. Molecularly imprinted polyaniline-polyvinyl sulphonic acid composite based sensor for para-nitrophenol detection

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Biomimetic para-nitrophenol (PNP) imprinted sensor is used to detect PNP. •The PVSA doped polyaniline shows high conductivity. •The sensor shows excellent sensitivity, 18 times reusability and higher stability. •PANI-PVSA composite shows increased stability of the sensor. -- Abstract: We report results of the studies relating to the fabrication and characterization of a conducting polymer based molecularly imprinted para-nitrophenol (PNP) sensor. A water pollutant, para-nitrophenol is electrochemically imprinted with polyvinyl sulphonic acid (PVSA) doped polyaniline onto indium tin oxide (ITO) glass substrate. This PNP imprinted electrode (PNPI-PANI-PVSA/ITO) prepared via chronopotentiometric polymerization and over-oxidation is characterized by Fourier transform infra-red spectroscopy (FT-IR), UV–visible (UV–vis) spectroscopy, contact angle (CA), scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. The response studies of PNPI-PANI-PVSA/ITO electrode carried out using DPV reveal a lower detection limit of 1 × 10−3 mM, improved sensitivity as 1.5 × 10−3 A mM−1 and stability of 45 days. The PNPI-PANI-PVSA/ITO electrode shows good precision with relative standard deviation of 2.1% and good reproducibility with standard deviation of 3.78%

  17. Molecular phylogeny of Asian Meconopsis based on nuclear ribosomal and chloroplast DNA sequence data.

    Science.gov (United States)

    Liu, Yu-Cheng; Liu, Ya-Nan; Yang, Fu-Sheng; Wang, Xiao-Quan

    2014-01-01

    The taxonomy and phylogeny of Asian Meconopsis (Himalayan blue poppy) remain largely unresolved. We used the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) and the chloroplast DNA (cpDNA) trnL-F region for phylogenetic reconstruction of Meconopsis and its close relatives Papaver, Roemeria, and Stylomecon. We identified five main clades, which were well-supported in the gene trees reconstructed with the nrDNA ITS and cpDNA trnL-F sequences. We found that 41 species of Asian Meconopsis did not constitute a monophyletic clade, but formed two solid clades (I and V) separated in the phylogenetic tree by three clades (II, III and IV) of Papaver and its allies. Clade V includes only four Asian Meconopsis species, with the remaining 90 percent of Asian species included in clade I. In this core Asian Meconopsis clade, five subclades (Ia-Ie) were recognized in the nrDNA ITS tree. Three species (Meconopsis discigera, M. pinnatifolia, and M. torquata) of subgenus Discogyne were imbedded in subclade Ia, indicating that the present definition of subgenera in Meconopsis should be rejected. These subclades are inconsistent with any series or sections of the present classifications, suggesting that classifications of the genus should be completely revised. Finally, proposals for further revision of the genus Meconopsis were put forward based on molecular, morphological, and biogeographical evidences. PMID:25118100

  18. Linearly programmed DNA-based molecular computer operated on magnetic particle surface in test-tube

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian; ZHANG Zhizhou; SHI Yongyong; Li Xiuxia; HE Lin

    2004-01-01

    The postgenomic era has seen an emergence of new applications of DNA manipulation technologies, including DNA-based molecular computing. Surface DNA computing has already been reported in a number of studies that, however, all employ different mechanisms other than automaton functions. Here we describe a programmable DNA surface-computing device as a Turing machine-like finite automaton. The laboratory automaton is primarily composed of DNA (inputs, output-detectors, transition molecules as software), DNA manipulating enzymes and buffer system that solve artificial computational problems autonomously. When fluoresceins were labeled in the 5′ end of (-) strand of the input molecule, direct observation of all reaction intermediates along the time scale was made so that the dynamic process of DNA computing could be conveniently visualized. The features of this study are: (i) achievement of finite automaton functions by linearly programmed DNA computer operated on magnetic particle surface and (ii) direct detection of all DNA computing intermediates by capillary electrophoresis. Since DNA computing has the massive parallelism and feasibility for automation, this achievement sets a basis for large-scale implications of DNA computing for functional genomics in the near future.

  19. An Evaluation of Neutron Energy Spectrum Effects in Iron Based on Molecular Dynamics Displacement Cascade Simulations

    International Nuclear Information System (INIS)

    The results of molecular dynamics (MD) displacement cascade simulations in bcc iron have been used to obtain effective cross sections for two measures of primary damage production: (1) the number of surviving point defects expressed as a fraction of the displacements calculated using the standard secondary displacement model of Norgett, Robinson, and Torrens (NRT), and (2) the fraction of the surviving interstitials contained in clusters that formed during the cascade event. Primary knockon atom spectra for iron obtained from the SPECTER code have been used to weight these MD-based damage production cross sections in order to obtain spectrally-averaged values for several locations in commercial fission reactors and materials test reactors. An evaluation of these results indicates that neutron energy spectrum differences between the various enviromnents do not lead to significant differences between the average primary damage formation parameters. In particular, the defect production cross sections obtained for PWR and BWR neutron spectra were not significantly different. The variation of the defect production cross sections as a function of depth into the reactor pressure vessel wall is used as a sample application of the cross sections. A slight difference between the attenuation behavior of the PWR and BWR was noted; this difference could be explained by a subtle difference in the energy dependence of the neutron spectra. Overall, the simulations support the continued use of dpa as a damage correlation parameter

  20. Fabrication of a SnO2-Based Acetone Gas Sensor Enhanced by Molecular Imprinting

    Directory of Open Access Journals (Sweden)

    Wenhu Tan

    2014-12-01

    Full Text Available This work presents a new route to design a highly sensitive SnO2–based sensor for acetone gas enhanced by the molecular imprinting technique. Unassisted and acetone-assisted thermal synthesis methods are used to synthesis SnO2 nanomaterials. The prepared SnO2 nanomaterials have been characterized by X-ray powder diffraction, scanning electron microscopy and N2 adsorption−desorption. Four types of SnO2 films were obtained by mixing pure deionized water and liquid acetone with the two types of as-prepared powders, respectively. The acetone gas sensing properties of sensors coated by these films were evaluated. Testing results reveal that the sensor coated by the film fabricated by mixing liquid acetone with the SnO2 nanomaterial synthesized by the acetone-assisted thermal method exhibits the best acetone gas sensing performance. The sensor is optimized for the smooth adsorption and desorption of acetone gas thanks to the participation of acetone both in the procedure of synthesis of the SnO2 nanomaterial and the device fabrication, which results in a distinct response–recovery behavior.

  1. Innovative molecular diagnosis of Trichinella species based on β-carbonic anhydrase genomic sequence.

    Science.gov (United States)

    Zolfaghari Emameh, Reza; Kuuslahti, Marianne; Näreaho, Anu; Sukura, Antti; Parkkila, Seppo

    2016-03-01

    Trichinellosis is a helminthic infection where different species of Trichinella nematodes are the causative agents. Several molecular assays have been designed to aid diagnostics of trichinellosis. These assays are mostly complex and expensive. The genomes of Trichinella species contain certain parasite-specific genes, which can be detected by polymerase chain reaction (PCR) methods. We selected β-carbonic anhydrase (β-CA) gene as a target, because it is present in many parasites genomes but absent in vertebrates. We developed a novel β-CA gene-based method for detection of Trichinella larvae in biological samples. We first identified a β-CA protein sequence from Trichinella spiralis by bioinformatic tools using β-CAs from Caenorhabditis elegans and Drosophila melanogaster. Thereafter, 16 sets of designed primers were tested to detect β-CA genomic sequences from three species of Trichinella, including T. spiralis, Trichinella pseudospiralis and Trichinella nativa. Among all 16 sets of designed primers, the primer set No. 2 efficiently amplified β-CA genomic sequences from T. spiralis, T. pseudospiralis and T. nativa without any false-positive amplicons from other parasite samples including Toxoplasma gondii, Toxocara cati and Parascaris equorum. This robust and straightforward method could be useful for meat inspection in slaughterhouses, quality control by food authorities and medical laboratories. PMID:26639312

  2. In situ injection of phenylboronic acid based low molecular weight gels for efficient chemotherapy.

    Science.gov (United States)

    Gao, Wenxia; Liang, Yan; Peng, Xinyu; Hu, Yalong; Zhang, Longgui; Wu, Huayue; He, Bin

    2016-10-01

    Injectable low molecular weight gels (LMWGs) based on the derivatives of phenylboronic acid were prepared and used as substrates for efficient in situ chemotherapy. The gelators as well as LMWGs were characterized by (1)H NMR, UV-vis, FTIR, MS and SEM. Anticancer drug doxorubicin hydrochloride (DOX) was encapsulated in the gels. The rheological properties and rapid recovery capability of both blank and drug-loaded gels were tested. The LMWGs were non-toxic to both 3T3 fibroblasts and 4T1 breast cancer cells. The gels were formed rapidly after injected in vivo. The in vivo anticancer activities of DOX-loaded LMWGs were investigated in breast cancer bearing mice. The intratumoral injection of DOX loaded LMWGs with dose of 30 mg/kg revealed that the gels could coat around the tumor tissues to release DOX sustainingly and maintain effective DOX concentration for chemotherapy. The systemic toxicity of DOX was reduced significantly with the in situ administration of LMWGs formulations. The injectable LMWGs exhibited excellent therapeutic efficacy and low side effects in local chemotherapy. PMID:27497056

  3. Molecular Basis of Spectral Diversity in Near-Infrared Phytochrome-Based Fluorescent Proteins.

    Science.gov (United States)

    Shcherbakova, Daria M; Baloban, Mikhail; Pletnev, Sergei; Malashkevich, Vladimir N; Xiao, Hui; Dauter, Zbigniew; Verkhusha, Vladislav V

    2015-11-19

    Near-infrared fluorescent proteins (NIR FPs) engineered from bacterial phytochromes (BphPs) are the probes of choice for deep-tissue imaging. Detection of several processes requires spectrally distinct NIR FPs. We developed an NIR FP, BphP1-FP, which has the most blue-shifted spectra and the highest fluorescence quantum yield among BphP-derived FPs. We found that these properties result from the binding of the biliverdin chromophore to a cysteine residue in the GAF domain, unlike natural BphPs and other BphP-based FPs. To elucidate the molecular basis of the spectral shift, we applied biochemical, structural and mass spectrometry analyses and revealed the formation of unique chromophore species. Mutagenesis of NIR FPs of different origins indicated that the mechanism of the spectral shift is general and can be used to design multicolor NIR FPs from other BphPs. We applied pairs of spectrally distinct point cysteine mutants to multicolor cell labeling and demonstrated that they perform well in model deep-tissue imaging. PMID:26590639

  4. Confirmation of natural hybrids between Gentiana straminea and G. siphonantha (Gentianaceae) based on molecular evidence

    Institute of Scientific and Technical Information of China (English)

    Xiaojuan LI; Liuyang WANG; Huiling YANG; Jianquan LIU

    2008-01-01

    A few individuals with intermediate morpho-logy always appeared in the sympatric distributions of Gentiana straminea and G. siphonantha. These intermedi-ate individuals were hypothesized to be the hybrids of two species after a careful evaluation of their morphological characteristics. To test this hypothesis, sequence compar-ison of the internal transcribed spacer (ITS) regions of the nuclear ribosomal and trnS (GCU)-trnG (UCC) inter-genic spacer region of the chloroplast DNA from Gentiana straminea, G. siphonantha and the putative hybrids was performed. The results suggest that most intermediate individuals were the natural hybrids between G. straminea and G. siphonantha. In addition, we exam-ined the sequence variation among the individuals of both parent species and analyzed the possibility leading to the incongruent identification in some individuals based on morphologic and molecular evidences, respectively. The intraspecific diversification of DNA fragments within both parent species and their high variability in hybrid swarms probably resulted from chloroplast genome recombination and incomplete lineage sorting during the early stages of speciation origin of the parent species.

  5. Nitride-based laser diodes grown by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    The progress in the growth of nitride-based laser diodes (LDs) made by plasma-assisted molecular beam epitaxy (PAMBE) is reviewed. In this work we describe the GaN and InGaN growth peculiarities, p-type doping efficiency, and the properties of InGaN quantum wells (QWs) grown by PAMBE. We demonstrate continuous wave (cw) LDs operating in the range from 410 to 482 nm. These LDs were grown on low dislocation (0 0 0 1) c-plane bulk GaN substrate, which allow one to fabricate cw LDs with a lifetime exceeding 2000 h. Also, the ultraviolet LDs at 388 nm grown on (2 0 −2 1) semipolar substrates are discussed. The use of high active nitrogen fluxes up to 2 µm/h during the InGaN growth was essential for pushing the lasing wavelengths of PAMBE LDs above 460 nm. Recent advancement of InGaN growth by PAMBE allows one to demonstrate high-quality quantum QWs and excellent morphology for thick layers. We discuss the influence of LDs design on their parameters such as lasing threshold current and laser beam quality. (topical review)

  6. Geometric filters for protein–ligand complexes based on phenomenological molecular models

    Directory of Open Access Journals (Sweden)

    Sudakov O. O.

    2013-09-01

    Full Text Available Molecular docking is a widely used method of computer-aided drug design capable of accurate prediction of protein-ligand complex conformations. However, scoring functions used to estimate free energy of binding still lack accuracy. Aim. Development of computationally simple and rapid algorithms for ranking ligands based on docking results. Methods. Computational filters utilizing geometry of protein-ligand complex were designed. Efficiency of the filters was verified in a cross-docking study with QXP/Flo software using crystal structures of human serine proteases thrombin (F2 and factor Xa (F10 and two corresponding sets of known selective inhibitors. Results. Evaluation of filtering results in terms of ROC curves with varying filter threshold value has shown their efficiency. However, none of the filters outperformed QXP/Flo built-in scoring function Pi . Nevertheless, usage of the filters with optimized set of thresholds in combination with Pi achieved significant improvement in performance of ligand selection when compared to usage of Pi alone. Conclusions. The proposed geometric filters can be used as a complementary to traditional scoring functions in order to optimize ligand search performance and decrease usage of computational and human resources.

  7. Molecular dynamics simulation of edge dislocation piled at cuboidal precipitate in Ni-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Yashiro, Kisaragi; Naito, Masato; Tomita, Yoshihiro [Kobe Univ., Dept. of Mechanical Engineering, Kobe, Hyogo (Japan)

    2003-01-01

    In order to clarify the fundamental mechanism of dislocations in the {gamma}/{gamma}' microstructure of Ni-based superalloy, three molecular dynamics simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the pure Ni matrix ({gamma}) toward cuboidal Ni{sub 3}Al precipitates ({gamma}') under shear force. One involves dislocations near the apices of two precipitates adjoining each other with the distance of 0.04 {mu}m, as large as the width of the {gamma} channel in real superalloys. Others simulate dislocations piled at the precipitates as well, however, the scale of the microstructure is smaller than that in real superalloys by one order of magnitude, and one of them have precipitates with atomistically sharp edge. Dislocations are pinned at precipitates and bowed-out in the {gamma} channel, then they begin to penetrate into the precipitate at the edge in both the real-scale and smaller microstructures when the precipitates have blunt edges. On the other hand, an edge dislocation splits into a superpartial in the {gamma}' precipitate and a misfit screw dislocation bridging between two adjacent precipitates at the atomistically sharp edge of {gamma}' precipitates. It is also observed that two superpartials glide in the precipitate as a superdislocation with anti-phase boundary (APB), of which the width is evaluated to be about 4 nm. (author)

  8. Molecular dynamics simulation of edge dislocation piled at cuboidal precipitate in Ni-based superalloy

    International Nuclear Information System (INIS)

    In order to clarify the fundamental mechanism of dislocations in the γ/γ' microstructure of Ni-based superalloy, three molecular dynamics simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the pure Ni matrix (γ) toward cuboidal Ni3Al precipitates (γ') under shear force. One involves dislocations near the apices of two precipitates adjoining each other with the distance of 0.04 μm, as large as the width of the γ channel in real superalloys. Others simulate dislocations piled at the precipitates as well, however, the scale of the microstructure is smaller than that in real superalloys by one order of magnitude, and one of them have precipitates with atomistically sharp edge. Dislocations are pinned at precipitates and bowed-out in the γ channel, then they begin to penetrate into the precipitate at the edge in both the real-scale and smaller microstructures when the precipitates have blunt edges. On the other hand, an edge dislocation splits into a superpartial in the γ' precipitate and a misfit screw dislocation bridging between two adjacent precipitates at the atomistically sharp edge of γ' precipitates. It is also observed that two superpartials glide in the precipitate as a superdislocation with anti-phase boundary (APB), of which the width is evaluated to be about 4 nm. (author)

  9. MZmine 2: Modular framework for processing, visualizing, and analyzing mass spectrometry-based molecular profile data

    Directory of Open Access Journals (Sweden)

    Villar-Briones Alejandro

    2010-07-01

    Full Text Available Abstract Background Mass spectrometry (MS coupled with online separation methods is commonly applied for differential and quantitative profiling of biological samples in metabolomic as well as proteomic research. Such approaches are used for systems biology, functional genomics, and biomarker discovery, among others. An ongoing challenge of these molecular profiling approaches, however, is the development of better data processing methods. Here we introduce a new generation of a popular open-source data processing toolbox, MZmine 2. Results A key concept of the MZmine 2 software design is the strict separation of core functionality and data processing modules, with emphasis on easy usability and support for high-resolution spectra processing. Data processing modules take advantage of embedded visualization tools, allowing for immediate previews of parameter settings. Newly introduced functionality includes the identification of peaks using online databases, MSn data support, improved isotope pattern support, scatter plot visualization, and a new method for peak list alignment based on the random sample consensus (RANSAC algorithm. The performance of the RANSAC alignment was evaluated using synthetic datasets as well as actual experimental data, and the results were compared to those obtained using other alignment algorithms. Conclusions MZmine 2 is freely available under a GNU GPL license and can be obtained from the project website at: http://mzmine.sourceforge.net/. The current version of MZmine 2 is suitable for processing large batches of data and has been applied to both targeted and non-targeted metabolomic analyses.

  10. Meshless reconstruction method for fluorescence molecular tomography based on compactly supported radial basis function

    Science.gov (United States)

    An, Yu; Liu, Jie; Zhang, Guanglei; Ye, Jinzuo; Mao, Yamin; Jiang, Shixin; Shang, Wenting; Du, Yang; Chi, Chongwei; Tian, Jie

    2015-10-01

    Fluorescence molecular tomography (FMT) is a promising tool in the study of cancer, drug discovery, and disease diagnosis, enabling noninvasive and quantitative imaging of the biodistribution of fluorophores in deep tissues via image reconstruction techniques. Conventional reconstruction methods based on the finite-element method (FEM) have achieved acceptable stability and efficiency. However, some inherent shortcomings in FEM meshes, such as time consumption in mesh generation and a large discretization error, limit further biomedical application. In this paper, we propose a meshless method for reconstruction of FMT (MM-FMT) using compactly supported radial basis functions (CSRBFs). With CSRBFs, the image domain can be accurately expressed by continuous CSRBFs, avoiding the discretization error to a certain degree. After direct collocation with CSRBFs, the conventional optimization techniques, including Tikhonov, L1-norm iteration shrinkage (L1-IS), and sparsity adaptive matching pursuit, were adopted to solve the meshless reconstruction. To evaluate the performance of the proposed MM-FMT, we performed numerical heterogeneous mouse experiments and in vivo bead-implanted mouse experiments. The results suggest that the proposed MM-FMT method can reduce the position error of the reconstruction result to smaller than 0.4 mm for the double-source case, which is a significant improvement for FMT.

  11. Fluorescence- and capillary electrophoresis (CE)-based SSR DNA fingerprinting and a molecular identity database for the Louisiana sugarcane industry

    Science.gov (United States)

    A database of Louisiana sugarcane molecular identity has been constructed and is being updated annually using FAM or HEX or NED fluorescence- and capillary electrophoresis (CE)-based microsatellite (SSR) fingerprinting information. The fingerprints are PCR-amplified from leaf DNA samples of current ...

  12. A DNA tetrahedron-based molecular beacon for tumor-related mRNA detection in living cells.

    Science.gov (United States)

    Xie, Nuli; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Quan, Ke; Wang, He; Ying, Le; Ou, Min; Wang, Kemin

    2016-02-01

    Due to its low cytotoxicity, high resistance to enzymatic degradation, and cellular permeability, a DNA tetrahedron-based molecular beacon (DTMB) is designed for tumor-related TK1 mRNA detection in living cells, where the target sequence can induce the tetrahedron from contraction to extension, resulting in fluorescence restoration. PMID:26729323

  13. Network-based integration of molecular and physiological data elucidates regulatory mechanisms underlying adaptation to high-fat diet

    NARCIS (Netherlands)

    Derous, D.; Kelder, T.; Schothorst, E.M. van; Erk, M. van; Voigt, A.; Klaus, S.; Keijer, J.; Radonjic, M.

    2015-01-01

    Health is influenced by interplay of molecular, physiological and environmental factors. To effectively maintain health and prevent disease, health-relevant relations need to be understood at multiple levels of biological complexity. Network-based methods provide a powerful platform for integration

  14. HIGHLY SELECTIVE SENSORS FOR CHEMICAL AND BIOLOGICAL WARFARE AGENTS, INSECTICIDES AND VOCS BASED ON A MOLECULAR SURFACE IMPRINTING TECHNIQUE

    Science.gov (United States)

    Abstract was given as an oral platform presentation at the Pittsburgh Conference, Orlando FL (March 5-9, 2006). Research described is the development of sensors based on molecular surface imprinting. Applications include the monitoring of chemical and biological agents and inse...

  15. Proposal of flexible atomic and molecular process management for Monte Carlo impurity transport code based on object oriented method

    International Nuclear Information System (INIS)

    Monte Carlo simulation code on impurity transport has been developed by several groups to be utilized mainly for fusion related edge plasmas. State of impurity particle is determined by atomic and molecular processes such as ionization, charge exchange in plasma. A lot of atomic and molecular processes have been considered because the edge plasma has not only impurity atoms, but also impurity molecules mainly related to chemical erosion of carbon materials, and their cross sections have been given experimentally and theoretically. We need to reveal which process is essential in a given edge plasma condition. Monte Carlo simulation code, which takes such various atomic and molecular processes into account, is necessary to investigate the behavior of impurity particle in plasmas. Usually, the impurity transport simulation code has been intended for some specific atomic and molecular processes so that the introduction of a new process forces complicated programming work. In order to evaluate various proposed atomic and molecular processes, a flexible management of atomic and molecular reaction should be established. We have developed the impurity transport simulation code based on object-oriented method. By employing object-oriented programming, we can handle each particle as 'object', which enfolds data and procedure function itself. A user (notice, not programmer) can define property of each particle species and the related atomic and molecular processes and then each 'object' is defined by analyzing this information. According to the relation among plasma particle species, objects are connected with each other and change their state by themselves. Dynamic allocation of these objects to program memory is employed to adapt for arbitrary number of species and atomic/molecular reactions. Thus we can treat arbitrary species and process starting from, for instance, methane and acetylene. Such a software procedure would be useful also for industrial application plasmas

  16. Molecular-based rapid inventories of sympatric diversity: A comparison of DNA barcode clustering methods applied to geography-based vs clade-based sampling of amphibians

    Indian Academy of Sciences (India)

    Andrea Paz; Andrew J Crawford

    2012-11-01

    Molecular markers offer a universal source of data for quantifying biodiversity. DNA barcoding uses a standardized genetic marker and a curated reference database to identify known species and to reveal cryptic diversity within well-sampled clades. Rapid biological inventories, e.g. rapid assessment programs (RAPs), unlike most barcoding campaigns, are focused on particular geographic localities rather than on clades. Because of the potentially sparse phylogenetic sampling, the addition of DNA barcoding to RAPs may present a greater challenge for the identification of named species or for revealing cryptic diversity. In this article we evaluate the use of DNA barcoding for quantifying lineage diversity within a single sampling site as compared to clade-based sampling, and present examples from amphibians. We compared algorithms for identifying DNA barcode clusters (e.g. species, cryptic species or Evolutionary Significant Units) using previously published DNA barcode data obtained from geography-based sampling at a site in Central Panama, and from clade-based sampling in Madagascar. We found that clustering algorithms based on genetic distance performed similarly on sympatric as well as clade-based barcode data, while a promising coalescent-based method performed poorly on sympatric data. The various clustering algorithms were also compared in terms of speed and software implementation. Although each method has its shortcomings in certain contexts, we recommend the use of the ABGD method, which not only performs fairly well under either sampling method, but does so in a few seconds and with a user-friendly Web interface.

  17. La experiencia narrativa y la comprensión metafórica del tiempo musical

    OpenAIRE

    Jacquier, María de la Paz

    2012-01-01

    La presente tesis se desarrolla en torno a una investigación teórico-empírica de la experiencia narrativa del tiempo musical, abordada desde el estudio de la experiencia temporal con el aporte de la teoría de la conceptualización metafórica. La elección de este tema surge, por un lado, de la reflexión pedagógica. A partir de mi labor como docente de Educación Auditiva (FBA-UNLP), donde se analizan diferentes componentes musicales principalmente desde la audición, me encuentro inmersa en un...

  18. El significado del aborto para la adolescente que ha vivido la experiencia

    OpenAIRE

    Marquina, Mary; Bracho, Cira

    2007-01-01

    El estudio está inserto en la línea de investigación “El Cuidado en la Experiencia Humana de la Salud en diferentes grupos poblacionales”, Doctorado en Enfermería, Universidad de Carabobo. El objetivo fue develar el significado que tiene para las adolescentes su experiencia del aborto y construir, mediante teoría sustantiva, un modelo teórico explicatorio. El estudio se desarrolló en el Municipio Libertador, capital del estado Mérida, enmarcado en el paradigma cuali...

  19. APRENDIENDO CON LAS TIC: UNA EXPERIENCIA UNIVERSITARIA (LEARNING FROM THE ICTS: A UNIVERSITY EXPERIENCE)

    OpenAIRE

    Regueyra Edelman María Gabriela

    2011-01-01

    Resumen:Se comparte en este artículo la experiencia del uso de las TIC en dos cursos que se imparten en la carrera de Trabajo Social de la Universidad de Costa Rica. Se detallan los recursos tecnológicos utilizados y el uso que se da a cada uno: Facebook, Blogger, Moodle, correo electrónico, se complementa la experiencia con la incorporación de las opiniones de la población estudiantil matriculada en los cursos y destacando los retos que el uso de las TIC presenta a la población docentes en p...

  20. Experiencias de fluidez y bienestar psicológico : Un estudio con adultos mayores

    OpenAIRE

    Sabatini, María Belén; Arias, Claudia Josefina

    2009-01-01

    Desde el marco conceptual de la Psicología Positiva, se presentan los resultados de un trabajo de investigación que explora las relaciones entre experiencias de fluidez y bienestar psicológico en adultos mayores residentes en la ciudad de Mar del Plata. Las experiencias de fluidez se definen como un estado psicológico especial caracterizado por la concentración o absorción completa en una actividad o situación. La activación motivacional depende, no solamente de la novedad o interés intrínsec...