In-cell recordings with 3D microelectrode arrays

Micro Electrode Arrays (MEAs) have been used for 40 years to record extracellular signal from electrically excitable cells. The development of three dimensional microstructured electrodes has been shown to improve the electrical contact between cell and electrode. This can allow to reduce the electrode dimensions to improve spatial resolution, to have a one-toone correspondence between cell and electrode and, applying an electrical stimulus, to obtain in-cell like recordings. In-cell like recordings resemble in their time course the transmembrane voltage obtained by an intracellular sharp electrode during electrical activity. Appropriate electrical stimulation transiently increases the leakage membrane conductance and gives access to a signal substantially different from the extracellular one. The aim of this thesis is to develop different electrodes designs and to investigate on cardiomyocytes cell cultures the feasability of in-cell recordings. Standard MEAs (tip-shaped and planar electrodes) were compared with self-developed MEAs. The duration of the in-cell signal, his amplitude, the voltage threshold to induce it and his repeatability over minutes and hours were studied by varying the stimulus duration and the stimulus voltage. We successfully processed solid and hollow pillars electrodes as well as mushroom-shaped electrodes. On these electrodes we recorded extracellular action potential from cardiomyocytes. The stimulation protocols successfully evoked in-cell like signals on all the electrodes. In-cell recordings could be obtained onto the same cell over several hours and occasionally days. Hollow pillars induced longer in-cell recording, tip-shaped electrode had a lower threshold. However the large variability of in-cell like recordings on the different electrode shapes does not suggest one particular shape to be used in future. A promising spontaneous in-cell recording was obtained in one culture, opening to future development on three-dimensional microelectrodes research. I Micro Electrode Array (matrici di micro elettrodi) sono stati usati negli ultimi 40 anni per registrare segnale extracellulare da cellule eccitabili come i neuroni. Lo sviluppo di elettrodi tridimensionali microstrutturati ha permesso di aumentare il contatto elettrico tra cellula ed elettrodo. Questo può essere sfruttato per aumentare la risoluzione spaziale, avere una corrispondenza unoa- uno tra cellula ed elettrodo e, applicando uno stimolo elettrico, per ottenere un segnale similintracellulare detto "in-cell". Questo tipo di segnale assomiglia al potenziale di membrana misurato da un elettrodo appuntito intracellulare durante un potenziale d'azione. La stimolazione elettrica infatti, aumentando transitoriamente la conducibilità della membrana da accesso ad un segnale sostanzialmente differente da quello extracellulare. Lo scopo di questa tesi è di sviluppare diverse forme e design di elettrodo e di investigare su colture cellulari di cardiomiociti la fattibilità di registrazioni "in-cell". Oltre agli elettrodi autoprodotti, sono stati confrontati elettrodi "a punta" e planari, disponibili in commercio. Gli elettrodi sono stati confrontati cambiando la durata e la tensione dello stimolo elettrico, per valutare le variazioni nella durata del segnale "in-cell", la sua ampiezza, la soglia di tensione che lo induce, e la ripetibilità per minuti ed ore. Abbiamo creato con successo elettrodi con la forma di cilindri pieni e vuoti e "a fungo", registrato potenziali d'azione extracellulari da cardiomiociti con essi, e ottenuto la registrazione di segnali "in-cell" con l'applicazione di protocolli di stimolazione elettrica. È stato possibile ripetere questi protocolli sulle stesse cellule per diverse ore e a volte giorni. I cilindri vuoti hanno indotto le registrazioni "in-cell" più lunghe, elettrodi a punta hanno mostrato una soglia di tensione inferiore. Ciononostante, la grande variabilità di questi risultati non suggerisce nessun tipo di forma preferenziale da usare in futuro. Un promettente segnale “in-cell” spontaneo (senza bisogno di stimolazione elettrica) è stato ottenuto in un caso, aprendo a futuri sviluppi nella ricerca sui microelettrodi tridimensionali.ope

Evaluating the impact of strategic personnel policies using a MILP model: the public university case

Purpose: The main purpose of the paper is to evaluate the impact of diverse personnel policies around personnel promotion in the design of the strategic staff plan for a public university. The strategic staff planning consists in the determination of the size and composition of the workforce for an organization. Design/methodology/approach: The staff planning is solved using a Mixed Integer Linear Programming (MILP) model. The MILP model represents the organizational structure of the university, the personnel categories and capacity decisions, the demand requirements, the required service level and budget restrictions. All these aspects are translated into a set of data, as well as the parameters and constraints building up the mathematical model for optimization. The required data for the model is adopted from a Spanish public university. Findings: The development of appropriate policies for personnel promotion can effectively reduce the number of dismissals while proposing a transition towards different preferable workforce structures in the university. Research limitations/implications: The long term staff plan for the university is solved by the MILP model considering a time horizon of 8 years. For this time horizon, the required input data is derived from current data of the university. Different scenarios are proposed considering different temporal trends for input data, such as in demand and admissible promotional ratios for workers. Originality/value: The literature review reports a lack of formalized procedures for staff planning in universities taking into account, at the same time, the regulations on hiring, dismissals, promotions and the workforce heterogeneity, all considered to optimize workforce size and composition addressing not only an economic criteria, but also the required workforce expertise and the quality in the service offered. This paper adopts a formalized procedure developed by the authors in previous works, and exploits it to assess the impact of various personnel policies in the staff planning for a particular university case, and this is the principal contribution of the paper.Postprint (published version

Una gesta cordobesa: el descubrimiento y la conquista del Nuevo Reino de Granada

Conferencia leída el día 26 de octubre de 1935, en la apertura de curso de la Academia de Ciencias, Bellas Letras y Nobles Artes de Córdob

Socioeconomic deprivation status and air pollution by PM10 and NO2: an assessment at municipal level of 11 years in Italy

The aim of this observational study was to assess the relationship between environmental risk factors and some aspects of social economic status (SES) of the population in different Italian municipalities. Nitrogen dioxide (NO2) and particulate matter (PM10) annual means were extracted from ISPRA-BRACE (environmental information system of 483 Italian municipalities, 6% of the total amount of administrative units) from 2002 to 2012. As an indicator of sociodemographic and SES data, we collected the following: resident population, foreign nationality, low level of education, unemployment, nonhome ownership, single-parent family, and overcrowding. Low educational level, unemployment, and lack of home ownership were indirectly associated with the higher mean values of NO2 at the statistically significant level (). Major resident population and rental housing percentage determined higher levels of PM10. Northern regions showed similar results compared to the national level, with the exception of foreign residency that showed direct correlation with the increase of PM10. The central regions showed a direct relationship between NO2 and PM10 levels and higher educational levels and between NO2 levels and percentage of single-parent family. In the southern areas, higher NO2 levels were correlated with a higher rental housing percentage, as well as higher PM10 levels with a higher percentage of unemployment and lower housing density. The study shows high heterogeneity in the findings but confirms the relationship between high educational level and employment with the increased concentration of pollutants. The higher rental housing percentage may increase the pollutants’ levels too. The housing density does not seem to be in relationship with NO2 and PM10 at the national level. The analysis stratified by geographical areas showed that the direction of the correlations was different over time as the analysis was at a national level. The study represents an example of how data from national information systems can provide a preliminary evaluation and be a comparative tool for policy-makers to assess environmental risk factors and social inequalities

Optimisation of the production of fermentable monosaccharides from algal biomass grown in photobioreactors treating wastewater

Producción CientíficaBiomass grown in wastewater treatment photobioreactors is a cheap raw material with high contents of carbohydrates, proteins and lipids. This work studies the production of fermentable monosaccharides from three biomasses grown in piggery wastewater (P), domestic wastewater (W) and synthetic medium (S) by applying chemical pretreatment and enzymatic hydrolysis, using a Taguchi design. ANOVA identified temperature, chemical reagent type and chemical reagent concentration as significant operational parameters. However, the biomass concentration, pretreatment time, enzyme dosage and enzymatic hydrolysis time had no remarkable effect. The bacterial content of the biomass had no relevant impact on carbohydrate and protein solubilisation but had a remarkable effect on the degradation of the released carbohydrates (57, 60 and 37% for P, W and S), while also affecting lipid solubilisation. Pretreatment with HCl 2 M at 120 °C resulted the optimal conditions, achieving a monosaccharide recovery of 53, 59 and 80% for P, W and S biomasses, respectively.Gobierno regional de Castilla y León (UIC 071, CLU 2017-09 and VA080G18)Ministerio de Ciencia, Innovación y Universidades (project CTQ2017-84006-C3-1-R)Unión Europea - FEDER (CLU 2017-09 and CTQ2017-84006-C3-1-R

José Mª Jover y la historia de las relaciones internacionales en las últimas décadas del siglo XIX y de las primeras del XX.

Sin resume

Preparando la Conferencia de Algeciras: el acuerdo hispano francés de 1 de septiembre de 1905 sobre Marruecos

Sin resume