Influence of classroom acoustics on the vocal behavior of teacers

Erroneous vocal behavior of teachers and their changes in the voice production due to poor acoustics in classrooms can be investigated through recently developed voice-monitoring devices. These devices are portable analyzers that use a miniature contact-microphone glued to the jugular notch in order to sense the skin acceleration level due to the vibration of the vocal folds. They estimate the Sound Pressure Level (SPL) at a certain distance from the speaker's mouth provided that a preliminary calibration procedure is performed, the fundamental frequency and the time dose. Two different devices are compared in this work: the former is a commercial device, whose phonation sensor is a small accelerometer; the latter, recently developed by the authors, uses an electret condenser microphone to sense the skin acceleration level. SPL and fundamental frequency are estimated over fixed-length frames and the results that refer to a sample of 25 primary school teachers and a university professor are analyzed. The duration of the voice and pause periods is investigated in order to detect the peaks of occurrence and accumulation in different conditions of reverberation. A method for the detection and analysis of the emphatic speech is also propose

Fluorescent polymeric carbon dots: from synthesis and elucidation of chemical struture towards photoactive hybrid materials

En este trabajo se cubren tres aspectos fundamentales de la investigación en el campo de los carbón dots (CDs). A través de detallados estudios estructurales, caracterización óptica y cálculos teóricos, la primera parte de la tesis consigue identificar las estructuras orgánicas y las fuerzas que producen la fluorescencia azul. En la segunda parte, se ha presentado un nuevo método para controlar la estructura y las propiedades químicas de nanopartículas poliméricas, ofreciendo una herramienta muy versátil para el diseño de materiales basados en CDs como sensores y vectores de fármacos. En la tercera y última parte de la tesis, a partir de los CDs y dicalcogenuros de metales de transición (MoS2 y WS2) se han preparado materiales híbridos, con vistas a su posible uso en aplicaciones de fotocatálisis y conversión de energía. <br /

Thiophene-Based Trimers and Their Bioapplications: An Overview

Certainly, the success of polythiophenes is due in the first place to their outstanding electronic properties and superior processability. Nevertheless, there are additional reasons that contribute to arouse the scientific interest around these materials. Among these, the large variety of chemical modifications that is possible to perform on the thiophene ring is a precious aspect. In particular, a turning point was marked by the diffusion of synthetic strategies for the preparation of terthiophenes: the vast richness of approaches today available for the easy customization of these structures allows the finetuning of their chemical, physical, and optical properties. Therefore, terthiophene derivatives have become an extremely versatile class of compounds both for direct application or for the preparation of electronic functional polymers. Moreover, their biocompatibility and ease of functionalization make them appealing for biology and medical research, as it testifies to the blossoming of studies in these fields in which they are involved. It is thus with the willingness to guide the reader through all the possibilities offered by these structures that this review elucidates the synthetic methods and describes the full chemical variety of terthiophenes and their derivatives. In the final part, an in-depth presentation of their numerous bioapplications intends to provide a complete picture of the state of the art.Operational Program Research, Development, and Education Project “MSCAfellow4@MUNI” (No. CZ.02.2.69/0.0/0.0/20_079/0017045) is acknowledged. The European Union is acknowledged for funding this research through Horizon 2020 MSCA-IF-2018 No 838171 (TEXTHIOL)

Chitosan-Modified Polyethyleneimine Nanoparticles for Enhancing the Carboxylation Reaction and Plants' CO2 Uptake

Increasing plants' photosynthetic efficienc y is a major challenge that must be addressed in order to cover the food demands of the growing population in the changing climate. Photosynthes i s is greatly limited at the initial carboxylation reaction, where CO2 is converted to the organic acid 3-PGA, catalyzed by the RuBisCO enzyme. RuBisCO has poor affinity for CO2, but also the CO2 concentration at the RuBisCO site is limited by the diffusion of atmospheric CO2 through the various leaf compartments to the reaction site. Beyond genetic engineer-ing, nanotechnology can offer a materials-based approach for enhancing photosynthesis, and yet, it has mostly been explored for the light-dependent reactions. In this work, we developed polyethyleneimine-based nanoparticl e s for enhancing the carbox-ylation reaction. We demonstrate that the nanoparticles can capture CO2 in the form of bicarbonate and increase the CO2 that reacts with the RuBisCO enzyme, enhancing the 3-PGA production in in vitro assays by 20%. The nanoparticles can be introduced to the plant via leaf infiltration and, because of the functionalization with chitosan oligomers, they do not induce any toxic effect to the plant. In the leaves, the nanoparticles localize in the apoplastic space but also spontaneously reach the chloroplasts where photosynthetic activity takes place. Their CO2 loading-dependent fluorescence verifies that, in vivo, they maintain their abi l i t y to capture CO2 and can be therefore reloaded with atmospheric CO2 while in planta. Our results contribute to the development of a nanomaterials-based CO2-concentrating mechanism in plants t h a t can potentially increase photosynthetic efficiency and overall plants' CO2 storage

Evaluation of the efficacy of carbon nanotubes for delivering peptides into mitochondria

Mitochondrial (mt) diseases are devastating neurodegenerative pathologies due tomutations in nuclear or mt genes. Among mtDNA pathogenic mutations, more than one half have been identified in transfer RNA (tRNA) genes. These are responsible for a wide range of pathologies including myopathies, encephalopathies, cardiomyopathies and deafness for which no effective treatment is available at present. Therefore, new strategies to suppress their damaging effects are required to envisage therapeutic approaches for these diseases. Here we report data for carbon nanotube (CNT) derivatives showing that the conjugates bearing a specific peptide sequence are able to target the mitochondria in yeast and human monocyte cells while the control derivative without the peptide diffuses into the cytoplasm. Moreover the compounds do not affect cellular viability and cytotoxicity both in vitro and in vivo. Toxicity of the constructs is also assessed on the simple pluricellular model Caenorhabditis elegans

Fluorescent polymeric carbon dots: from synthesis and elucidation of chemical structure towards photoactive hybrid materials

250 Pags.-Tabls, Figs. Anexos.-- Tesis realizada en el Instituto de Carboquímica (ICB-CSIC), llevada a cabo para conseguir el grado de Doctor en la Universidad de Zaragoza, leída el 26 febrero de 2019.-- Sobresaliente "cum laude".[EN] This work covers three fundamental aspects in the field of carbon dots (CDs). The first part describes detailed structural, optical and theoretical studies which lead to the identification of the chemical structure and the origin of the universal blue fluorescence of CDs. The second part presents a new method enabling the control of the structure and the chemical properties of the polymeric CDs, thus offering a highly versatile toolbox for the design of CDs suitable for applications in sensing and medical applications. The third part focusses on the preparation of novel hybrid materials based on CDs and transition metal dichalcogenides (MoS2 and WS2) para su uso en aplicaciones de photocatalysis and energy conversion.[ES] En este trabajo se cubren tres aspectos fundamentales de la investigación en el campo de los carbón dots (CDs). A través de detallados estudios estructurales, caracterización óptica y cálculos teóricos, la primera parte de la tesis consigue identificar las estructuras orgánicas y las fuerzas que producen la fluorescencia azul. En la segunda parte, se ha presentado un nuevo método para controlar la estructura y las propiedades químicas de nanopartículas poliméricas, ofreciendo una herramienta muy versátil para el diseño de materiales basados en CDs como sensores y vectores de fármacos. En la tercera y última parte de la tesis, a partir de los CDs y dicalcogenuros de metales de transición (MoS2 y WS2) se han preparado materiales híbridos, con vistas a su posible uso en aplicaciones de fotocatálisis y conversión de energía.This work has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No. 642742.Peer reviewe

Citric Acid-Based Carbon Dots and Their Application in Energy Conversion

Carbon dot (CD) is a general term that encompasses a plethora of organic materials obtained from different reagents and different synthetic routes. Beyond this variety, carbonization has been considered for a long time as the essential process whereby completely different precursors converge into the formation of nanosized particles with resembling optical properties. In particular, CDs’ outstanding fluorescence emission is frequently attributed to the existence of large aromatic structures with extended conjugation. Nevertheless, thanks to the contribution of an increasing number of publications, nowadays the impact of these structures on the fluorescence emission has been considerably downsized. In some cases, their existence is even highly questionable. In return, in these years, more solid interpretations have been provided, according to which the chemical and emissive nature of CDs is strictly specific to the combination of synthetic precursors employed. Moreover, researchers have become more aware of the complexity of these systems, which contain not only nanoparticles but also single molecules, oligomers, and aggregates with their own fluorescent behavior. Therefore, we dedicate the first part of this review to the individual examination of different classes of citric acid-based CDs as a benchmarking CD class. A classification based on the precursors is meant to help the reader to find a common thread between the structural and optical properties of CDs. In the second part, we discuss the employment of citric acid-based CDs for energy conversion applications. This includes their exploitation as components of light-emitting diodes (LEDs), as photocatalysts for hydrogen generation and pollutant degradation, and as additives in several types of organic photovoltaic devices

Nanostructured complexes of conducting polymers and graphene oxide

1 figure.-- Talk delivered at the 9th Nanodays Workshop on Advanced Materials, Munich (Germany), Sept. 13-15, 2017Intrinsically conducting polymers form the base for the development of plastic electronic devices and hold great promise in optoelectronic applications such as thin film organic field-effect transitors, OLEDS and solar cells. Control of morphology and aggregation states by nanostructuring is essential for improving the device performance. In the last decade, research has focused on liquid phase assembly processes. These afford conjugated polymers in the form of nanoparticles or nanowires, which are dispersible in aqueous dispersions and allow for the fabrication of thin films with well-defined characteristics from environmentally-friendly solutions. Moreover, the liquid phase self-assembly processes provide unique opportunities for the development of novel composite materials with graphene based materials [1, 2]. Here we present our results of our recent work on the development of novel composite materials based of graphene oxide and poly (3-hexylthiophene) (P3HT) [3]. We show that liquid phase assembly processes in the presence of water-soluble graphene oxide sheets lead to the formation P3HT nanoparticles (P3HTNPs) in intimate contact with surrounding sheets of graphene oxide. During the synthesis, graphene oxide acts as a >good> solvent and induces important changes on the internal aggregation structure and the related interchain coupling. At the same time, the charge-transfer properties as a function of GO concentration are modified. Both effects are intimately coupled and lead to the stabilization of of P3HTNPs-GO donor-acceptor nanostructures offering improved charge transport and charge separation characteristics in thin films.Funding by EU (Project H2020-ITN 2014 642742), Spanish MINECO (ENE2013-48816-C5-5-R) and Government of Aragon (DGA-ESF-T66), is gratefully acknowledged

Voice Care - A low-cost Platform for Monitoring Voice Professionals

For voice professionals, erroneous vocal behavior or changing in the voice ​ ​ production due to poor acoustics in the environment where the voice ​ ​ is used, can be investigated through recently developed voice monitoring ​ ​ devices. These devices are portable data-logger that use a miniature accelerometer ​ ​ glued to the jugular notch as a sensor of the skin acceleration ​ ​ level due to the vibration of the vocal folds. They estimate the SPL at ​ ​ a certain distance from the speaker’s mouth as a result of a calibration. ​ ​ Other provided parameters are the fundamental frequency and the time ​ ​ dose. Uncertainty specifications are not always available and the cost is in ​ ​ some cases prohibitive for a large monitoring campaign. The low-cost platform ​ ​ ”Voice Care” is proposed in this contribution, that includes a wearable ​ data-logger and a processing program that allows the vocal parameters to be extracted from the recorded signal. The data-logger is equipped with a​ ​ contact microphone as a phonation sensor. Suitable calibration procedures​ ​ are implemented for the estimated parameters and their effectiveness ​ is shown through specifically conceived experimental tests. Uncertainties​ ​ are estimated and experimental results are reported that refer to the normal​ ​ use of the device during monitoring interval of several hours in university​​ classrooms