Use of Higher-Harmonic and Intermodulation Generation of Ultrasonic Waves to Detecting Cracks due to Steel Corrosion in Reinforced Cement Mortar

The aim of this work was to provide further confirmation of the possible use of non-linear ultrasonic techniques for detecting the cracking due to corrosion of steel reinforcements in concrete. To this end accelerated steel corrosion tests have been conducted on model reinforced cement mortar specimens, while monitoring the appearance and width evolution of visible surface cracks, and performing non-linear ultrasonic measurements based on the phenomena of harmonic distortion and intermodulation. A new parameter, based on the difference between the amplitude of the fundamental frequency and the sum of the amplitudes of all the first-order and second-order intermodulation products, has been proposed in this work. The results confirm that the appearance of visible surface micro-cracks are preceded and accompanied by the observation of strong non-linear features in the received signal. Furthermore, the new parameter proposed in this work is as efficient as the relative non-linearity parameters, classically used in harmonic distortion non-linear ultrasonic studies, for detecting the non-linear features associated with the critical events of the cracking of cement mortar due to embedded steel corrosion. A hypothesis has been developed considering the possible effect of the filling of the void space by liquid containing rust products after the formation of new cracks or the enlargement of its width. This filling process, which might be particularly enhanced by net convective transport of liquid, would explain the evolution of the values of all the parameters used for putting in evidence the non-linear elastic features after the critical events of the cracking process.This research was funded by the Spanish Agencia Estatal de Investigación (Grant code BIA2016-80982-R) and by the European Regional Development Fund (Grant code BIA2016-80982-R)

Sostenibilidad y laboratorios escolares

In this work we present a study of how environmental sustainability deals with on secondary school centres. The analysis includes the current status in teaching chemistry at secondary level: laboratory teaching, classroom books and the point of view of chemistry teachers about the environmental hazard of some of the chemicals used along in these tasks. In order to derive conclusions we start proposing the following questions: 1. Which dangerous substances for the environment can be found in the secondary school laboratories and how frequently are they used? 2. What is done with the products after a chemical reaction? 3. Are the chemistry teachers aware of the dangerous substances used and stored in their laboratories? 4. Which hazardous substances for the environment are proposed in the secondary chemistry books to perform practical works? Is the given information about their impact on the environment enough

Non-Destructive Evaluation of Internal Sulphate Attack in Cement-Based Materials Applying Non-Linear Ultrasonic Techniques

One of the most aggressive attacks to which cement-based materials can be exposed is that produced by sulphate. During this attack, expansive products are formed, causing volumetric strains in hardened materials, which brings microcracking and the reduction of their strength and durability. The use of non-destructive techniques for characterizing the microstructure of cement-based materials, and for following the development of deleterious processes which can affect them, has become an important research field. Among them, non-linear ultrasonic (NLU) techniques have shown to be useful for evaluating the material degradation. The aim of this work is to study the possibility of using the NLU technique for the non-destructive evaluation of initial development of internal sulphate attack in cement-based materials. Cement pastes were prepared using ordinary Portland cement, to which an appropriate amount of calcium sulphate 2-hydrate was added during the setting for producing an internal attack in the samples. Furthermore, its effects in the microstructure have been followed with mercury intrusion porosimetry. The expansion and linear ultrasonic pulse velocity were also determined. The preliminary results indicate that the NLU technique could be useful for studying the development of sulphate attacks in the short-term, complementing the information provided by other techniques.This research was funded by the Conselleria de Educación, Investigación, Cultura y Deporte (at present re-named as Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital) de la Generalitat Valenciana (Spain) (grant code GV/2019/070), by the Spanish Agencia Estatal de Investigación (grant code BIA2016-80982-R) and by the European Regional Development Fund (grant code BIA2016-80982-R). M. M. is indebted to Spanish Ministerio de Educación, Cultura y Deporte for a pre-doctoral fellowship (FPU16/04078)

Early Detection of Corrosion-Induced Concrete Micro-cracking by Using Nonlinear Ultrasonic Techniques: Possible Influence of Mass Transport Processes

This work presents results allowing an unequivocal correlation of the observations of strong nonlinear elastic features of ultrasonic waves (values of the nonlinearity parameters exceeding the thresholds corresponding to undamaged states), with the critical events of the corrosion-induced surface cracking of reinforced cement-mortar specimens. These observations point to the possibility of the early detection of cracking using nonlinear ultrasonic (NLU) techniques. Experimental evidence is presented on the existence of active net mass transport processes, due to wick action, in the course of the corrosion tests, in the experimental conditions of this work. These phenomena might explain the observed abrupt shifting of the nonlinear parameter values (typically increasing and then decreasing post-peak, even reaching values typical of the undamaged state), and, partially, the high variability obtained for the values of the nonlinear parameters in damaged (cracked) states. Finally, some consequences are derived from the point of view of use of the NLU techniques in engineering practice, i.e., in surveys aimed at evaluating reinforced concrete structures affected by corrosion.This research was funded by the Spanish Agencia Estatal de Investigación (grant code BIA2016-80982-R) and by the European Regional Development Fund (grant code BIA2016-80982-R). M.M. acknowledges a pre-doctoral fellowship from the Spanish Ministerio de Educación, Cultura y Deporte (FPU16/04078)

Crystallization Induced Enhanced Emission in Two New Zn(II) and Cd(II) Supramolecular Coordination Complexes with the 1-(3,4-Dimethylphenyl)-5-Methyl-1H-1,2,3-Triazole-4-Carboxylate Ligand

Two new d10 metal supramolecular metal-organic frameworks (SMOFs) with general formula [ML2(H2O)2]n (M = Zn, Cd) have been synthetized using the sodium salt of the anionic 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand (Na+L−). Both SMOFs have been structurallycharacterizedbysingle-crystalX-raydiffractionanalysisandIRspectroscopy. Thecompounds are isostructural and form supramolecular aggregates via hydrogen bonds with the presence of less common dihydrogen bonds. Interestingly, they show ionic conductivity and porosity. The luminescent properties have been also studied by means of the excitation and emission spectra. Periodic DFT and molecular TD-DFT calculations have been used to unravel the emergence of luminescence in the otherwise non-emitting 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand once incorporated in the SMOFs. Our results also illustrate the importance of considering the dielectric environment in the crystal when performing excited state calculations for isolated fragments to capture the correct electronic character of the low-lying states, a practice which is not commonly adopted in the community

Seguimiento del Grado en Geología (Facultad de Ciencias, Universidad de Alicante, curso 2015-16)

La Facultad de Ciencias de la Universidad de Alicante ha constituido una red de trabajo formada por los profesores coordinadores de semestre del Grado en Geología, así como por los coordinadores responsables de la titulación. Los objetivos de esta red son: Asegurar la ejecución efectiva de las enseñanzas conforme al contenido del plan de estudios del título verificado; detectar posibles deficiencias en su implementación, proponiendo recomendaciones y sugerencias de mejora; y evidenciar los progresos en el desarrollo del Sistema de Garantía Interno de Calidad (SGIC) tanto en lo relativo a la revisión de la aplicación del plan de estudios como a la propuesta de acciones para mejorar su diseño en la implantación. El método de trabajo se basa en reuniones en las que los miembros de la red plantearán y debatirán los parámetros e indicadores de seguimiento de la red. Cada coordinador llevará a cabo una investigación individualizada del semestre del que es responsable en coordinación con los miembros de su comisión. Asimismo, se participará en la elaboración de los informes de autoevaluación del título

Natural killer cells act as an extrinsic barrier for <i>in vivo</i> reprogramming

The ectopic expression of transcription factors Oct4, Sox2, Klf4 and Myc (OSKM) enables reprogramming of differentiated cells into pluripotent embryonic stem cells. Methods based on partial and reversible in vivo reprogramming are a promising strategy for tissue regeneration and rejuvenation. However, little is known about the barriers that impair reprogramming in an in vivo context. We report that natural killer (NK) cells significantly limit reprogramming, both in vitro and in vivo. Cells and tissues at the intermediate states of reprogramming upregulate the expression of NK activating ligands, such as MULT1 and ICAM1. NK cells recognize and kill partially reprogrammed cells in a degranulation-dependent manner. Importantly, in vivo partial reprogramming is strongly reduced by adoptive transfer of NK cells, whereas it is significantly improved by depletion of NK cells. Notably, in the absence of NK cells, the pancreatic organoids derived from OSKM-expressing mice are remarkably large, suggesting the generation of cells with progenitor properties. We conclude that NK cells pose an important barrier for in vivo reprogramming, and this concept may apply to other contexts of transient cellular plasticity

Use of Non-Linear Ultrasonic Techniques to Detect Cracks Due to Steel Corrosion in Reinforced Concrete Structures

In this work, non-linear ultrasonic wave techniques have been used to detect the onset of micro-cracking due to steel corrosion in model reinforced concrete elements. The specimens were of prismatic shape with a single steel rebar. The corrosion was forced by admixing an appropriate amount of sodium chloride at the moment of preparing the concrete mix, and by the application of an electric field, using a constant current density power source, and making the steel rebar work as the anode, and an external counter-electrode as the cathode. The preliminary results indicate that the onset of cracking seems to be accompanied by the appearance of higher-harmonic generation at the output signal (harmonic distortion), when the system is excited by the means of an ultrasound wave with a burst central frequency. Other phenomena related to the micro-cracks induced by corrosion, such is the parametric generation with respect to the fundamental amplitude, have not been observed until now.This research was funded by the Spanish Agencia Estatal de Investigación (grant code BIA2016-80982-R) and by the European Regional Development Fund (grant code BIA2016-80982-R). M. M. acknowledges a pre-doctoral fellowship from the Spanish Ministerio de Educación, Cultura y Deporte (FPU16/04078)

Nuevas aportaciones al horizonte del bronce final de La Vital (Gandia, València)

Durante las tareas de seguimiento arqueológico de las obras de construcción del Acceso Sur a Gandia se localizaron diferentes estructuras negativas datadas en el Bronce final ubicadas en el perímetro de protección del yacimiento de La Vital. Las estructuras documentadas corresponden a un lugar de hábitat fechado en estos momentos. En este trabajo presentamos los resultados de dicha actuación, valorándolos en el marco del desarrollo histórico de este periodo en el propio yacimiento y en la costa mediterránea peninsular

MicroRNA profile in very young women with breast cancer

BACKGROUND: Breast cancer is rarely diagnosed in very young women (35 years old or younger), and it often presents with distinct clinical-pathological features related to a more aggressive phenotype and worse prognosis when diagnosed at this early age. A pending question is whether breast cancer in very young women arises from the deregulation of different underlying mechanisms, something that will make this disease an entity differentiated from breast cancer diagnosed in older patients. METHODS: We performed a comprehensive study of miRNA expression using miRNA Affymetrix2.0 array on paraffin-embedded tumour tissue of 42 breast cancer patients 35 years old or younger, 17 patients between 45 and 65 years old and 29 older than 65 years. Data were statistically analyzed by t-test and a hierarchical clustering via average linkage method was conducted. Results were validated by qRT-PCR. Putative targeted pathways were obtained using DIANA miRPath online software. RESULTS: The results show a differential and unique miRNA expression profile of 121 miRNAs (p-value <0.05), 96 of those with a FDR-value <0.05. Hierarchical clustering grouped the samples according to their age, but not by subtype nor by tumour characteristics. We were able to validate by qRT-PCR differences in the expression of 6 miRNAs: miR-1228*, miR-3196, miR-1275, miR-92b, miR-139 and miR-1207. Moreover, all of the miRNAs maintained the expression trend. The validated miRNAs pointed out pathways related to cell motility, invasion and proliferation. CONCLUSIONS: The study suggests that breast cancer in very young women appears as a distinct molecular signature. To our knowledge, this is the first time that a validated microRNA profile, distinctive to breast cancer in very young women, has been presented. The miRNA signature may be relevant to open an important field of research in order to elucidate the underlying mechanism in this particular disease, which in a more clinical setting, could potentially help to identify therapeutic targets in this particular set of patients.MPC is funded by the Generalitat Valenciana VALi + d, ACIF/2011/270. MTM is funded by”Rio Hortega Project” (CM12/00264). GR is a FIS “Miquel Servet” Researcher. AB holds a Translational Research Grant awarded by the Spanish Society of Medical Oncology (SEOM). This project was carried out thanks to Fundación LeCadó – proyecto Flor de Vida and co-funded by FIS project PI13/00606 and FEDER. We would like to give thanks to all the patients and volunteers for their participation and also to the INCLIVA Biobank, integrated into the Spanish Hospital Biobanks Network (ReTBioH) and supported by the Instituto de Salud Carlos III/FEDER (grant number: RD09/0076/00132). We also wish to thank several private Breast cancer associations that funded this study and the Unit for Multigenic Analysis from the Central Unit for Medical Research (UCIM/INCLIVA) for the performance of the Affymetrix microRNA profiles.S