Biochemical analysis and optimization of inhibition and adsorption phenomena in glass-silicon PCR-chips

Altres ajuts: this work was partly funded by the Consejo de Investigaciones Cientı́ficas (CSIC), by Grant TIC97-0569 from the Comisión Interministerial de Ciencia y Tecnologı́a (CICYT)The use of glass-silicon chips for PCR analysis has been widely reported in the last decade, but there have been few systematic efforts to pin down the biochemical problems such systems bring forth. Here we report a systematic analysis of material-related inhibition and adsorption phenomena in glass-silicon PCR-chips. The results suggest that the previously reported inhibition of PCR by silicon-related materials stems mainly from the adsorption of Taq polymerase at chip walls due to increased surface-to-volume ratios, and not from a straight chemical action of silicon-related materials on the PCR-mix. In contrast to Taq polymerase, DNA is not adsorbed in noticeable amounts. The net effect of polymerase adsorption can be counteracted by the addition of a titrated amount of competing protein bovine serum albumin (BSA) and the ensuing reactions can be kinetically optimized in chips to yield effective amplifications in the whereabouts of 20 mi

Morphological and Magnetic Properties of Superparamagnetic Carbon-Coated Fe Nanoparticles Produced by Arc Discharge.

Spherical carbon coated iron particles of nanometric diameter in the 5-10 nm range have been produced by arc discharge at near-atmospheric pressure conditions (using 5-8·10 4 Pa of He). The particles exhibit a crystalline dense iron core with an average diameter 7.4 ± 2.0 nm surrounded by a sealed carbon shell, shown by transmission electron microscopy (TEM), selected-area diffrac- tion (SAED), energy-dispersive X-ray analysis (STEM-EDX) and electron energy loss spectroscopy (EELS). The SAED, EDX and EELS results indicate a lack of traces of core oxidized phases showing an efficient protection role of the carbon shell. The magnetic properties of the nanoparticles have been investigated in the 5-300 K temperature range using a superconducting quantum interference device (SQUID). The results reveal a superparamagnetic behaviour with an average monodomain diameter of 7.6 nm of the nanoparticles. The zero field cooled and field cooled (ZFC-FC)magnetization curves show a blocking temperature (TB)at room temperature very suitable for biomedical applications (drug delivery, magnetic resonance imaging-MRI-, hyperthermia)

. Ethical self-regulation systems for Non-governmental organizations (NGOs).

[ES] : El artículo presenta los principales resultados teóricos de una investigación centrada en los sistemas de autorregulación como aproximación evaluativa a la performance ética de las ONG. Su objetivo es analizar los actuales sistemas de autorregulación en las ONG para reconocer su campo de actuación, identificar qué dimensiones y variables evaluativas utilizan, y clarificar su función en relación a otras estrategias y recursos aparentemente afines como son los sistemas de calidad. A partir de la revisión de la literatura y el análisis de contenido de las principales bases de datos y documentos institucionales de entidades promotoras y gestoras de diferentes sistemas de autorregulación, se describen, comparan y analizan las actuales prácticas. Los resultados nos llevan a concluir quemediantemecanismos de autorregulación, principalmente los códigos de conducta y las certificaciones de buenas prácticas, un número creciente de entidades están desarrollando estándares y normas comunes para atender y canalizar oportunamente la emergente exigencia de transparencia y responsabilidad ante los grupos de interés. No obstante se observa gran disparidad en sus usos, distribución geográfica y contenidos. Finalmente se formula una propuesta integradora de las distintas variables utilizadas en la evaluación de la gestión ética por parte de los principales sistemas de certificación analizados. [EN] : The article presents the theoretical results of a study focusing on self-regulatory systems as the evaluative approach to the ethical performance of NGOs. Its aim is to analyse the current self-regulatory systems in NGOs in orderto report their scope, identify the evaluative dimensions and variables used, and clarify their role in relation to other strategies and other apparently similar resources, such as quality control systems. From the literature survey and content analysis of the major databases and institutional documents of authors and managers of various self-regulatory systems, the current practices are described, compared and analysed. The results lead us to conclude that through self-regulation, primarily codes of conduct and certifications of good practices, a growing number of organizations are developing standards and shared rules of conduct to address and channel the emerging demand for transparency and accountability to their stakeholders.However, there is great disparity in the way they are used, along with their geographical distribution and content. Finally, we offer an integrative proposal of the different variables used to evaluate ethical management in the leading certification systems analysed

Pseudomonas graminis strain CPA-7 differentially modulates the oxidative response in fresh-cut ‘Golden delicious’ apple depending on the storage conditions

The oxidative response in fresh-cut antioxidant-treated‘Golden delicious’apples during chilling storage wasdifferentially modified by the biopreservative bacteriumPseudomonas graminisCPA-7 depending on the storageconditions (passive modified atmosphere packaging (MAP) or air). Results showed that inoculation with CPA-7had no influence on fruit quality parameters in any of the conditions tested. During thefirst 24 h both in air andin MAP, ascorbate peroxidase (APX) activity triplicated the initial level in response to CPA-7, reaching up to 4-fold the activity of non-inoculated fruit (control). From 24 h of storage in MAP, polyphenol oxidase (PPO)activity was sharply enhanced in response to CPA-7 attaining values up to 8-fold higher than that of the controlat the end of the experiment, yet it was not paired to an increase in browning incidence. Concomitantly, at 24 hof storage in MAP, CPA-7 suppressed peroxidase (POX) and catalase (CAT) activities. Subsequently, after 3 d insuch conditions, superoxide dismutase (SOD) and PPO activities were almost duplicated in the presence of CPA-7compared to the control. On the other hand, when stored in air, POX showed a biphasic induction in response toCPA-7 after 1 d and 6 d of incubation. On day 6, this enzyme duplicated its activity in inoculated samplescompared to the control regardless of storage conditions. Inoculation with CPA-7 led to the slowdown of thedecline of antioxidant capacity in air, which contrasted with the response upon MAP conditions. These resultssuggest that CPA-7 may trigger the activation of the fruit defense-response thereby mitigating its oxidativedamage. Such activation may play a role as a putative biocontrol mechanism against foodborne pathogen in-fections.info:eu-repo/semantics/acceptedVersio

Experiencia de innovación docente siguiendo las directrices del Espacio Europeo de Educación Superior en la enseñanza del diseño digital

El nuevo marco educativo superior establecido en la declaración de Bolonia ha introducido en nuestra metodología docente una serie de cambios muy significativos que, a nivel autonómico catalán, ha sido liderado por el DURSI (Departament d’Universitats, Recerca i Societat de la Informació). De esta forma, dicho departamento propuso la adaptación de ciertas titulaciones al futuro modelo europeo (EEES) entre las que se hallaba la de Ingeniería Informática. El departamento al que pertenecemos (Microelectrónica y Sistemas Electrónicos), ha puesto en marcha la implantación de una nueva metodología docente en un reducido número de asignaturas troncales, pertenecientes a la citada titulación, donde existe como factor común entre ellas, un alto grado de especialización tecnológica y un gran número de alumnos (más de 200). El objetivo fundamental de este trabajo es mostrar todo el proceso de adaptación que ha sido necesario para la ejecución con plenas garantías de dicha reforma educativa en nuestra asignatura (Diseño de Sistemas Digitales), así como todas las herramientas didácticas utilizadas para poder implantar dichas técnicas en una asignatura con un alto grado de experimentación práctica en los laboratorios y fomentar un mayor grado de participación y consecución de objetivos por parte del alumnado. Para conseguir el éxito final de dicho proceso, hemos utilizado una metodología docente basada en el PBL (“Problem Based Learning”), en el uso intensivo del conocido “e-learning, así como en una introducción progresiva al aprendizaje cooperativo; siempre siguiendo las directrices del grupo IDES (Grupo de Innovación Docente en Educación Superior) de la UAB. La asignatura en cuestión, ha sido estructurada en tres grandes secciones: Sesiones de teoría; Seminarios de problemas y Sesiones de laboratorios. En la sección de resultados evaluaremos el alto grado de objetivos cumplidos, la mejora significativa en el trabajo cooperativo, el incremento de la capacidad de organización y planificación, así como la buena capacidad en la resolución de problemas. A su vez, se ha conseguido que se haya obtenido un 91% de superación de la asignatura de los alumnos que han seguido los seminarios.The new higher educative framework established in the Bologna Declaration has introduced to our educational methodology a series of very significant changes that, at Catalan autonomic level, have been conducted by the DURSI (the Catalan Ministry of Universities, Research and the Information Society). With this aim, the ministry proposed the adaptation of certain degrees to the future European model, being Computer Engineering one of them. The department which we belong to (Department of Microelectronics and Electronic Systems), has started up the implantation of a new teaching methodology in a small number of core subjects, belonging to the aforementioned degree, which have in common a high level of technological specialization and a large number of students (more than 200). The main goal of our paper is to explain all the adaptation process that has been necessary for the execution of this educative reform in the subject we teach (Digital System Design). We also show all the didactic tools used to implant the new teaching methodology in a subject with a high level of experimentation in the laboratories. These tools also foment a greater degree of participation and attainment of objectives on the students’ part. In order to successfully carry out this process, we have used an educational methodology based on the Problem Based Learning technique (PBL) [2], the intensive use of e‐learning and the progressive introduction to the cooperative learning [3], always following the directives of the Unit for Innovation in Higher Education Teaching (IDES) from the UAB. The subject at issue has been structured in three great sections: Theory classes; Problem seminars y Laboratory sessions. In the results section, we will present the high level of fulfilled objectives, the significant improvement in cooperative working, the organization and planning capacity increase as well as the good aptitude in problem resolution. Moreover, the 91 per cent of the students who followed the seminars passed the subject

Study of the effect of the chromophore and nuclearity on the aggregation and potential biological activity of gold(I) alkynyl complexes

The synthesis and characterization of four organometallic gold(I) complexes containing different water soluble phosphanes (TPPTS, PTA and DAPTA) and chromophoric units (4-pyridylethynyl and propargyloxycoumarin) is here reported. The analysis of their absorption and emission spectra led us to attribute their luminescent behavior to the chromophoric organic ligands. Moreover, the presence of the gold(I) metal atom has been observed to be the responsible of an efficient intersystem crossing process responsible for the observed phosphorescence emission. Broad emission bands are observed in most cases due to the formation of organized aggregates in solution in agreement with microscopic characterization. Biological activity of the complexes showed very low effects against tumor cell growth but an inhibitory potency against thioredoxin reductase (TrxR). The missing/low cytotoxic effects could be related to a low bioavailability as determined by atomic absorption spectroscopy. Graphical abstract The synthesis, characterization, aggregation and emissive properties of four organometallic gold(I) complexes containing different water soluble phosphanes and chromophoric units is here reported. Biological activity of the complexes showed very low effects against tumor cell growth but an inhibitory potency against thioredoxin reductase (TrxR

Development of a CMOS-compatible PCR chip : comparison of design and system strategies

Altres ajuts: this work was partly funded by the Consejo Superior de Investigaciones Científicas (CSIC), by grant TIC97-0569 from the Comision Interministerial de Ciencia y Tecnología (CICYT).In the last decade research in chips for DNA amplification through the polymerase chain reaction (PCR) has been relatively abundant, but has taken very diverse approaches, leaving little common ground for a straightforward comparison of results. Here we report the development of a line of PCR chips that is fully compatible with complementary-metal-oxide-semiconductor (CMOS) technology and its revealing use as a general platform to test and compare a wide range of experimental parameters involved in PCR-chip design and operation. Peltier-heated and polysilicon thin-film driven PCR chips have been produced and directly compared in terms of efficiency, speed and power consumption, showing that thin-film systems run faster and more efficiently than Peltier-based ones, but yield inferior PCR products. Serpentine-like chamber designs have also been compared with standard rectangular designs and with the here reported rhomboidal chamber shape, showing that serpentine-like chambers do not have detrimental effects in PCR efficiency when using non-flow-through schemes, and that chamber design has a strong impact on sample insertion/extraction yields. With an accurate temperature control (±0.2 °C) we have optimized reaction kinetics to yield sound PCR amplifications of 25 µl mixtures in 20 min and with 24.4 s cycle times, confirming that a titrated amount of bovine albumin serum (BSA, 2.5 µg µl−1) is essential to counteract polymerase adsorption at chip walls. The reported use of a CMOS-compatible technological process paves the way for an easy adaption to foundry requirements and for a scalable integration of electro-optic detection and control circuitr

An innovative water-assisted UV-C disinfection system to improve the safety of strawberries frozen under cryogenic conditions

Strawberries inoculated with Salmonella enterica, Listeria monocytogenes (108 CFU/mL, 50 μL) and murine norovirus (MNV-1; 106 TCID50/mL, 50 μL), were washed for 2 min in a water-assisted UV-C light tank (WUVC) combined or not with 40 mg/L of peracetic acid (WUVC+PA), and 200 mg/L of free chlorine solution (NaClO) with the UV-C lamps switched off. Moreover, a ‘conventional’ dry UV-C treatment (DUVC) was also tested. After 2-min exposure, washing sanitization with chemical agents gave the highest reduction for both bacteria (ca. ≥ 3.3 log CFU/g) and MNV-1 (≥1.8 log TCID50/mL). DUVC treatment proved to be the least effective technology (≤0.6 log CFU/g for bacteria and 1.5 log TCID50/mL for MNV-1). Regarding wash water, no presence of L. monocytogenes and S. enterica were reported with WUVC+PA and NaClO sanitization. After disinfection, samples were frozen at − 70 ± 2 ◦C in a cryogenic freezing cabinet with liquid nitrogen (N2). For both pathogens, frozen storage after washing substantially enhanced their inactivation in the first 3 days (1.1–4.9 log UFC/g) compared to the reductions obtained the following sampling points (0.0–0.8 log UFC/g). After 90 days, L. monocytogenes and S. enterica were not detected on the samples treated with water-assisted methodologies (WUVC, WUVC+PA and NaClO treatments), whilst MNV-1 was little affected. Further studies are needed to improve norovirus inactivation on frozen strawberries. Industrial relevance: The present work provides relevant information to the frozen food industry regarding a suitable decontamination alternative to chlorine sanitation. Low-dose immersion-assisted UV-C allows inactivation and inhibition of pathogenic microbiota while generates non-toxic byproducts and allows reusing the process water, contributing to the so-called “smart green growth” attended to provide a more innovative and sustainable future for the food industry.FRESAFE AGL2016-78086-

Impact of Pseudomonas graminis strain CPA-7 on respiration and ethylene production in fresh-cut ‘Golden delicious’ apple according to the maturity stage and the preservation strategy

The effect of the biocontrol agent (BCA) Pseudomonas graminis CPA-7 on the accumulation of CO2 and ethylene (C2H4) in fresh-cut apples at two maturity stages was evaluated in refrigerated conditions. Factors involved in the preservation strategy applied upon commercial conditions such as the antioxidant (AOX) treatment and the storage system were included in the analysis. Regardless of the maturity stage, the BCA reduced C2H4 levels within the MAP atmosphere in AOX-untreated apples wedges, by 29 and 43% in immature and mature apples, respectively. Nevertheless, the addition of ascorbate as antioxidant counteracted this effect. In vitro tests suggested that the reduction of C2H4 levels was not associated to the uptake of this molecule by CPA-7. Interestingly, in non-inoculated samples AOX treatment showed contradictory effects on C2H4 production in MAP conditions by significantly reducing C2H4 levels in immature apples (by 23%) while increasing it in mature ones (by 40%). Similarly, CPA-7 had opposite effects on the CO2 accumulation pattern depending on the storage system or the fruit maturity stage. In this sense, CPA-7 was associated to a higher fruit respiratory activity at an advanced maturity stage yet without inducing the fruit fermentative metabolism or altering the fruit quality during a week of refrigerated storage. Overall, these results show that CPA-7 may contribute to the maintenance of the microbiological and physicochemical quality of fresh-cut apple by modulating the fruit ethylene production and/or respiration.This work has been supported by the CERCA Programme/Generalitat de Catalunya and by the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (grant FI-DGR-2015-0004). Thanks are given to Iolanda Nicolau, Silvia Villaró, Marina Anguera and Dr. Gloria Bobo for their technical support

Changes in respiration during emotional stress

In this work, we analyze changes in respiration during emotional stress induced by a modification of the Trier Social Stress Test. The following stages in the test were analyzed: the pre-relaxing stage, the story telling stage, the anticipation of stress and the video exposition stage. Respiration signal is recorded during the whole test using a thoracic band. Power spectral density (PSD) of respiration is computed in running windows using a modification of Welch periodogram in which sufficiently peaked spectra are averaged. Then, respiratory frequency (FR) is estimated from the peaked-conditioned averaged spectra. Results show that respiratory rate is significantly (p < 0.05 according to the Friedman test) higher, while a measure of spectral peakness and the percentage of PSD used to compute (FR) is lower during stress stages than during relax. These results suggest that the respiration-related parameters have potential discrimination power for stress level assessment