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Comparative analysis of ultrasound-accelerated alkaline and acid hydrolysis for the indirect determination of 3-monochloropropane-1,2-diol fatty acid esters
Get PDFUltrasound-accelerated hydrolysis is effectively used for the first time in the release of 3-monochloropropane-1,2-diol (3-MCPD) from its fatty esters. Indirect determination of 3-MCPDE fatty acid esters was performed under alkaline and acid conditions using sodium methoxide and sulfuric acid, respectively, prior to GC-MS analysis. Dispersive liquid-liquid microextraction (DLLME) was used to derivatize the free 3-MCPD with n-heptafluorobutyrylimidazole (HFBI). Two asymmetrical screening designs were used to evaluate parameters affecting the methods’ performances: time, temperature, hydrolytic agent volume, and concentration. A comparative study between both methods was performed. Research showed that comparable results are achieved in terms of linearity (r2 > 0.9995), specificity, accuracy, and precision. Determination limits were lower for the alkaline method (67 ng g−1). Twenty samples of four types of edible oil were assessed using both methods: extra virgin olive oil (EVO), refined sunflower oil, refined olive oil, and palm oil. Results obtained here were comparable and similar to those reported in the literature. Alkaline hydrolysis was the recommended approach and should be used in occurrence studies.S
Critical phenomena and vortex dynamics in superconductors of technological interest
Get PDFThis thesis focuses on several open questions of high-Tc
superconductors. Firstly, we study the vortex state of iron-based
superconductors (IBS), particularly the anomalous angular
dependence of the upper critical field, the second magnetization
peak in the critical state of highly anisotropic IBS, and the less
studied vortex pinning induced by surface irregularities.
Secondly, we investigate the highly debated nature of precursor
superconducting effects on cuprate superconductors. Our
findings deepen our understanding of the impact of nanostructuration
and dimensionality on superconducting properties,
with implications on the technological applications of
superconductors, by exploring mechanisms to enhance the
critical current and the irreversibility magnetic field
Manganese diagenesis in different geochemical environments of the ria de Vigo (Galicia, NW Iberian Peninsula)
Get PDFManganese is one of the most abundant elements in marine sediments and plays an essential role in sediment redox processes. However, unlike Fe or S, the Mn cycle has not received the same attention. Mn is a ubiquitous redox-active metal in marine systems; however, its influence on C and S cycling is still poorly understood. In particular, we hypothesize that conditions that favor high H2S production can lead to high Mn pyritization. In the Ria de Vigo, large methane fields have been identified at different depths within sediments, ranging from the surface to 2 m below the surface. Four sediment cores from different locations (outermost, middle, and innermost) within the Ria de Vigo were analyzed. Samples were subjected to a general characterization and a five-step Mn sequential extraction procedure, and analyses were complemented with X-ray absorption spectroscopy (EXAS). The results showed that the main geochemical forms of Mn undergo intense spatial and depth-related variations in sediments. Two geochemical scenarios were identified: one corresponding to the innermost section and another one to the middle and outermost sections of the ria. The former was characterized by intense Mn pyritization and by the absence of the Mn‑carbonate fraction due to the high production of H2S because of anaerobic oxidation of methane. The formation of Mnsingle bondS bonds was only identified by EXAS. Conversely, in the middle and outermost part of the ria, with or without the presence of methanogenesis in deep sediment layers, the Mn‑carbonate fraction was dominant even at depth, along with the presence of methane, high concentrations of H2S and, therefore, high degrees of Fe pyritization. These results suggest that, once Mn‑carbonate is formed under suboxic conditions (with low or no presence of H2S) at or near the surface, it remains stable after burial, even under conditions of high H2S concentrationThis research was co-funded by the Spanish Ministry of Economy and Competitiveness (CGL2012–33584) and the Consellería de Educación, Universidade e Formación Profesional-Xunta de Galicia (Axudas á consolidación e estruturación de unidades de investigación competitivas do SUG do Plan Galego IDT, Ambiosol Group ref. ED431C 2022/40). Thanks are due to María José Santiso for her assistance with laboratory work. The use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515S
Autocompensating two-photon quantum cryptography for optical fiber communication systems
No full textQuantum Key Distribution (QKD) is a technique that provides perfect secrecy for
communication systems, which is crucial against quantum computers capable of
breaking current public-key cryptosystems. QKD is becoming a mature technology
but it still suffers from implementation problems due to imperfections on real hardware
that soften it’s security. To correct those is necessary to develop error mitigation
mechanisms, as well as security by design through use of two-photon protocols.
In this Thesis, we combine these two approaches in fiber-based QKD, particularizing
for evolved fibers with improved data bandwidths. At the same time, we emphasize
integration with quantum photonics, and carry out actual microfabrication of basic
elements in the laboratory for future QKD applications
Smoking-attributable mortality by sex in the 27 Brazilian federal units: 2019
Get PDFObjectives
The aim of this study was to estimate smoking-attributable mortality (SAM) in the population aged 35 years and over in Brazil's 27 federal units by sex, in 2019.
Study design
This is an attributable mortality analysis.
Methods
We applied a method dependent on the prevalence of smoking, based on the population attributable fractions. Data on mortality due to causes causally related to smoking were derived from Brazil's Death Registry, data on prevalence of smoking from a survey conducted in Brazil in 2019, and data on relative risks from five US cohorts. Crude and age-adjusted SAM rates were calculated by sex. Estimates of SAM were calculated by specific causes of death and major mortality groups for each federal unit by sex.
Results
In 2019, smoking caused 480 deaths per day in Brazil. Although the SAM varied among the federal units, the pattern is not clear, with the greatest difference being between Rio Grande do Sul (crude rate: 248.8/100,000 inhabitants) and Amazonas (106.0/100,000). When the rates were adjusted by age, the greatest differences were observed between Acre (271.1/100,000) and Distrito Federal (131.1/100,000). SAM was higher in males; however, while the main specific cause of SAM in men was ischemic heart disease, in women it was chronic obstructive pulmonary disease. The major mortality group having the greatest impact on SAM across all federal units was the cardiometabolic diseases.
Conclusions
The variability in the burden of SAM in the different regions of Brazil reaffirms the need for SAM data disaggregated at the geographic levelThis study has been funded by Instituto de Salud Carlos III (ISCIII) through the project ‘PI19/00288’ and co-funded by the European UnionS
Análisis de la huella de memoria en casos de violencia de género con las categorías de contenido del Sistema de Evaluación Global
Get PDFEn esta investigación se aborda el análisis de la huella de
memoria en casos de violencia sobre la mujer ejercida por el
hombre. En las salas de justicia, los encargos a la psicología
forense efectuados por jueces, fiscales, o como prueba de
cargo aportada por la acusación, habitualmente se ciñen a
peticiones sobre evaluación y demostración del daño
psicológico. Pero, es igual de fundamental, para la toma de
decisiones judiciales, evaluar los criterios de realidad de
contenido del testimonio de la víctima/denunciante. Este
dictamen contribuye sobremanera a dotar la pericia de aptitud
probatoria. Y, por ende, a superar las limitaciones de la
incredibilidad subjetiva (vg., resentimiento), generalmente
invocada por la defensa del investigado para enervar el
principio constitucional de la presunción de inocencia
How transformational leadership shapes employee task performance? A sequential mediation model
Get PDFThe purpose of this study was to analyze through a sequential model the underlying mechanisms connecting transformational leadership with employee task performance. Specifically, it examined the causal chain transformational leadership-job characteristics (task variety and task significance)-job engagement-task performance.
The hypotheses were tested on a sample of 320 employees and their supervisors from Spanish young technology and knowledge-intensive small and medium-sized enterprises (SMEs), using structural equations.
The results show that the effect of transformational leadership on task performance (assessed by supervisors) occurs sequentially via task significance and job engagement. Additionally, job engagement mediates the relationship between task variety and task performance.
Findings highlight the relevance for supervisors to employ a transformational leadership style that leads employees directly and indirectly, through task significance, to be more engaged and achieve higher task performance. They also emphasize the importance of proper job design that allows employees to be fully invested in the job performance.
Despite the importance of leadership and employee performance for the survival and growth of these firms, the study of these relationships is largely unexplored. This study proposes and tests a serial model in which supervisor transformational leadership is linked to employee task performance through two sequential mediators: job characteristics (task variety and task significance) and job engagement.S
Biting into the truth: Connecting oral pathology and stable isotopes through the paradigmatic example of a hyper-specialized marine diet in Medieval Pontevedra (NW Iberia)
Get PDFHuman feeding patterns have been reconstructed in Archaeology by analysing either oral pathology or stable isotope ratios in human skeletal remains. However, no clear agreement has been developed between these two methodologies. The main objective of this study is to determine if we can establish a link between them when analysing a population with a hyper-specialized diet, in this case marine resources (and millet/maize). To reach this goal we developed a conjoined multi-isotope analysis using collagen and bioapatite (δ13Ccol, δ15Ncol and δ13Ccar) and a detailed study of oral health (caries, antemortem loss, periapical lesions, periodontal disease, calculus, and wear). All available skeletons with at least one preserved tooth from two cemeteries of the medieval town of Pontevedra (n = 34) were studied. The buried individuals belonged to the guild of fishers and artisans, professions which were dominant among the families of medieval Pontevedra. A detailed FTIR-ATR study of extracted bone bioapatite showed a high correlation between bioapatite carbonate content, carbonate typical vibrations, and FTIR-ATR indices related to bone diagenesis, which is in line with previous research. No significant correlations were found with bioapatite yield and isotopic composition (δ13Ccar and Δ13C), ruling out possible diagenetic effects. The diet was based on marine fish protein with contributions of millets (e.g., δ13Ccar -11.9 ± 1.8‰) that seems to be slightly higher in individuals linked to artisanal guilds. The oral pathology study shows severe dental wear from an early age (Grade 2–4 in permanent dentition for 20% of infants and 60% of juveniles in M1), as well as moderate-high presence of caries in permanent dentition (64%, 22/34) and dental calculus (72%, 24/33). Both the oral pathology and the isotopic signal differ from that observed in other areas of the Iberian Peninsula. This study points to the existence of connections between findings of the two methodologies, and specifically an association between intense dental wear and high consumption of marine resources and millet. At the same time, this analysis implies the necessity of caution in estimation of age by dental wear in populations linked to the seaThe authors would like to thank the Museo de Provincial de Pontevedra and Patrimonio Histórico de la Xunta de Galicia for granting access to skeletal material. We would like to thank Simon R. Doubleday for his helpful suggestions regarding Medieval Galicia and proofreading. Also, to thank Paula González Novoa for her collaboration in the laboratory analysis, and Noelia Rivero Chaver and Marta Colmenares Prado for helping with bioapatite extraction. Thanks to Claudia López-Morago and Inmaculada Alemán Aguilera for oral pathology comparisons. Finally, we also owe thanks to the anonymous reviewers whose comments helped us to improve the manuscript.
Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the projects Bolsas de Investigación de Artes e Humanidades by Diputación de A Coruña (BINV-AH/2021), Grupos de Referencia Competitiva (ED431C 2021/32) by Xunta de Galicia, and POLLUTIO Plan Nacional Retos project (PID2019-111683RJ-I00) Spanish Ministerio de Ciencia e Innovacion. Clara Veiga-Rilo is funded by predoctoral fellowship from Xunta de Galicia (ED481A 2022/205), Olalla López-Costas is funded by Ramón y Cajal 2020 (RYC2020-030531-I). The last part of this research was co-funded by the European Union (ERC Consolidator Grant, PollutedPast, 101087832). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for themS
A Mathematical Model for Axial Length Estimation in a Myopic Pediatric Population Based on Easily Obtainable Variables
Get PDFDetermining the axial length (AL) of the eye is of significant interest in managing myopia. However, the devices that allow this value to be obtained are either expensive, for example, optical biometers, or inconvenient for use in pediatric population, such is the case with ultrasound biometers. Therefore, this study aimed to develop a mathematical model for estimating the AL value based on easily obtainable variables, with the novel addition of body height to the analysis. A total of 170 eyes of 85 myopic volunteers (mean age of 10.8 ± 1.45 years, ranging from 7 to 14 years) were included in the analysis. Participants underwent anamnesis, keratometry by NVISION-K 5001, subjective refraction by an optometrist, AL measurement by the Topcon MYAH biometer, and body height measurement. Spearman’s correlation test was employed to analyze the relationships between AL and keratometry, spherical equivalent, body height (Sperman’s correlation, all r ≥ 0.267, all p < 0.001), and age (Spearman’s correlation, p = 0.081). Subsequently, multiple regression analysis was conducted on the variables that demonstrated a previous correlation. The mathematical model obtained permits the estimation of AL based on average keratometry, spherical equivalent, and body height. This model is significant (p < 0.001) and explains 82.4% of AL variability.S
Papel de la nedilación de PCK1 en la gluconeogénesis hepática
Get PDFLa nedilación es un mecanismo postraduccional que agrega una proteína similar a la ubiquitina, a saber, la proteína 8 regulada negativamente durante el desarrollo expresada por células precursoras neurales (NEDD8). En este trabajo mostramos en ratones que la nedilación en el hígado está modulada por la disponibilidad de nutrientes. La inhibición de la nedilación en el hígado de ratón reduce la capacidad gluconeogénica y las acciones hiperglucémicas de las hormonas contrarreguladoras. Además, las personas con diabetes tipo 2 presentan niveles elevados de nedilación hepática. A nivel mecanístico, el ayuno o la restricción calórica de ratones conduce a la nedilación de la fosfoenolpiruvato carboxiquinasa 1 (PCK1) en tres residuos de lisina: K278, K342 y K387. Encontramos que la mutación de las tres lisinas PCK1 que están nediladas reduce su tasa de actividad gluconeogénica. Las simulaciones de dinámica molecular muestran que la nedilación de PCK1 podría reposicionar dos bucles que rodean el centro catalítico en una configuración abierta, haciendo que el centro catalítico sea más accesible. Nuestro estudio revela que la nedilación de PCK1 proporciona un mecanismo preciso para controlar el metabolismo de la glucosa al vincular la disponibilidad total de nutrientes con la homeostasis metabólica