Assessing Single Upconverting Nanoparticle Luminescence by Optical Tweezers

We report on stable, long-term immobilization and localization of a single colloidal Er3+/Yb3+ codoped upconverting fluorescent nanoparticle (UCNP) by optical trapping with a single infrared laser beam. Contrary to expectations, the single UCNP emission differs from that generated by an assembly of UCNPs. The experimental data reveal that the differences can be explained in terms of modulations caused by radiation-trapping, a phenomenon not considered before but that this work reveals to be of great relevanceThis work was supported by the Spanish Ministerio de Educación y Ciencia (MAT2010–16161 and MAT2013–47395-C4–1-R). P.H.G. thanks the Spanish Ministerio de Economía y Competitividad (MINECO) for the Juan de la Cierva program. P.R.S thanks the Spanish Ministerio de Economía y Competitividad (MINECO) for the “Promoción 14 del talento y su Empleabilidad en I+D+i” statal program. Fondazione Cariverona (Verona, Italy) is gratefully acknowledged for financial support in the frame of the project “Verona Nanomedicine Initiative

Leaf litter decomposition in western Iberian forested wetlands : lentic versus lotic response

Leaf litter breakdown is frequently used to measure both structural and functional integrity in aquatic ecosystems. Forested wetlands are interface systems that received little attention, especially in the Iberian Peninsula. The present study compares the decomposition of alder and willow in two biotopes (lentic and lotic) located in two different sites (Caxarias and Alpiarça). Litterbags were used to compare decomposition among the different treatments. Throughout decay, dry weight loss, nitrogen and phosphorus content, microbial community physiological profiles, microbial and macro-invertebrate colonization were measured at days 2, 4, 8, 16, 32 and 64. Decomposition rates ranged from intermediate to rapid for alder (0.006 day−1 to 0.0338 day−1) and slow to rapid for willow (0.0024 day−1 to 0.0272 day−1), depending on site and biotopes type. The combined effects biotope × time was significant for heterotrophs (P < 0.05), molds (P < 0.05) and yeasts (P < 0.001). The analysis of average well colour development (AWCD), richness (R) and Shannon-Wiener index (H') based on the oxidation of carbon and nitrogen sources by the microbial community, showed differences between the two biotopes, lotic and lentic, and sites. These differences were also shown by the principal component analysis (PCA). Moreover, the macroinvertebrate communities clearly distinguished between lentic and lotic systems. The invertebrates belonging to Plecoptera, Ephemeroptera and Trichoptera were absent from lentic habitats.La descomposición de hojarasca se utiliza frecuentemente para medir la integridad estructural y funcional en los sistemas acuáticos. Los humedales arbolados son sistemas de transición que han recibido escasa atención especialmente en la Península Ibérica. El presente trabajo compara la descomposición de la hojarasca de aliso y sauce en dos sistemas (lenítico y lótico) situados en dos localidades (Caxarias y Alpiarça). Se utilizaron bolsas para hojarasca para comparar la descomposición entre los diferentes tratamientos. Se determinaron las pérdidas de peso seco, contenido en N y P en el detritus vegetal, perfiles fisiológicos de la comunidad microbiana, la colonización microbiana y de macroinvertebrados a los 2, 4, 8, 16, 32 y 64 días del experimento. Las tasas de descomposición variaron de intermedias a rápidas para el aliso (0.006 día−1 a 0.0338 día−1) y de lentas a rápidas para el sauce (0.0024 día−1 a 0.0272 día−1), dependiendo de la localidad de muestreo y del tipo de sistema. Los efectos combinados sistema × tiempo resultaron significativos para los heterótrofos totales (p < 0.05), hongos filamentosos (p < 0.05) y levaduras (p < 0.001). El análisis del desarrollo medio del color (AWCD), la riqueza (R) y el índice de Shannon-Wiener (H') basados en la oxidación de las fuentes de nitrógeno y carbono por parte de la comunidad microbiana, mostraron diferencias entre los dos sistemas, lótico y lenítico y entre las localidades de muestreo. Estas diferencias se pusieron también de manifiesto en el análisis de componentes principales (PCA). Además, las comunidades de macroinvertebrados claramente diferenciaron los sistemas leníticos de los lóticos. Se observó que en los sistemas leníticos los organismos pertenecientes a Plecoptera, Ephemeroptera y Trichoptera estaban ausentes

Catalytic activity of iridium NHC complexes covalently bonded to carbon nanotubes and graphene oxide

Trabajo presentado a la Annual World Conference on Carbon, celebrada en Dresden (Alemania) del 12 al 17 de julio de 2015.Carbon nanotubes and graphene have been extensively applied as proactive supports to generate heterogeneous catalysts. Both exhibit a carbon structure composed by carbon atoms with sp2 hybridization and both are used in similar applications, as in catalysis. However, the role of each particular substrate, determined by its structural peculiarities, can be differentvshould be studied for each particular catalytic reaction and in their structure.The aim of this work is to study the differences between oxidized carbon nanotubes (CNT) and graphene oxides (GO) as proactive supports of iridium Nheterocyclic carbene (NHC) catalyst. The effect of their inherent structure in the catalytic activity in hydrogen transfer reactions was studied in detail.The authors thank MINECO/MECD (Projects CONSOLIDER INGENIO 2010 CSD2009-00050, CTQ 2010-15221, Ramón y Cajal contract of P. Alvarez and fellowship of M. Blanco) and the Diputación General de Aragón (E07) for their financial support.Peer Reviewe

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

The GTK application for comet segmentation developed in this work is available at https://github.com/dsuarezgarcia/freecomet. The rest of the data presented in this study are available on request from the corresponding author.[Abstract]: Natural populations of the spider crab Maja brachydactyla constitute a fishery resource of great economic importance in many countries. As in the rest of eubrachyurans, the females of this species have ventral-type seminal receptacles where they store sperm from copulations. Sperm can be stored in these structures for months and even years before egg fertilisation, with the consequent degradation of the sperm cells during the time. In this work, we analyse the viability and the possible genetic damage in sperm accumulated in the seminal receptacles of M. brachydactyla females as a function of the storage time (from 0 to 14 months) using the comet assay technique. On one hand, we developed an algorithm for comet image analysis that improves the comet segmentation compared with the free software Open comet v1.3.1 (97% vs. 76% of detection). In addition, our software allows the manual modification of the contours wrongly delimited via the automatic tool. On the other hand, our data show a sharp decline in sperm viability and DNA integrity in the first four months of storage, which could lead to a decrease in the fecundity rate and/or viability of the embryos or larvae from the second and third clutches of the annual cycle if the repair capacity in these gametic cells is low.This research was funded by the Ministerio de Ciencia, Innovación y Universidades, grant number PID2019-109194RB-I00 MAR; and by the Ministerio de Ciencia e Innovación, grant number PID2020-113578RB-I00. It has also been supported by the Xunta de Galicia (Grupos de Referencia Competitiva ED431C-2020/14).Xunta de Galicia; ED431C-2020/1

Una experiencia para reforzar el aprendizaje autocrítico

El objetivo fue desarrollar y valorar una experiencia de aprendizaje con apoyo de MOODLE en una asignatura de segundo año de la carrera de odontología de la Universidad Nacional de La Plata (UNLP) para fomentar el aprendizaje autocrítico. Diseñamos bloques temáticos con actividades que tenían una instancia presencial con discusión en pequeños grupos y luego cada estudiante elaboraba una producción individual para entregar en forma virtual. El trabajo grupal presencial reforzaba el aprendizaje colaborativo mientras que las actividades asincrónicas pretendían promover en los participantes la organización y el desarrollo de habilidades comunicativas del lenguaje y el razonamiento crítico. Las tareas virtuales eran calificadas en una escala del 0 al 100 con un comentario de retroalimentación. No había una nota mínima para aprobar. Se determinó el rendimiento académico y la satisfacción de los estudiantes en relación a la experiencia de aprendizaje. Se establecieron frecuencias sobe las tareas entregadas y las calificaciones obtenidas. Se instrumentó un cuestionario tipo escala para conocer la opinión de los estudiantes. El 54,5% de los estudiantes entregó el total de tareas virtuales y un 30% aproximadamente 4 o 5. Sólo el 13,2% volvió a entregar la tarea corregida siendo los más interesados los de calificaciones altas. Con relación a la opinión de los estudiantes sobre la experiencia propuesta, el 85% acordó que trabajo en grupos le facilitó la resolución de las tareas. Valoraron el análisis de casos clínicos, la relación odontólogo paciente y la reflexión crítica del actuar odontológico. Un 85% de los estudiantes cree que la explicación del profesor es más importante que realizar las tareas. El nivel de satisfacción del curso fue bueno. Concluimos que los recursos virtuales optimizan los procesos de enseñanza aprendizaje, aunque requieren un replanteo del rol docente y del estudiante

Automatic generation of models for abdominal aortic aneurysms and intraluminal thrombus based on hexahedral meshes

To propose an automated patient-specific algorithm for the creation of accurate and smooth meshes of the aortic anatomy, to be used for evaluating rupture risk factors of abdominal aortic aneurysms (AAA). Finite element (FE) analyses and simulations require meshes to be smooth and anatomically accurate, capturing both the artery wall and the intraluminal thrombus (ILT). The two main difficulties are the modeling of the arterial bifurcations, and of the ILT, which has an arbitrary shape that is conforming to the aortic wall

Effect of Mixed Oxide-Based TiO2 on the Physicochemical Properties of Chitosan Films

The physicochemical, mechanical, and structural properties of chitosan-based films (CS) alone or CS-films with mixed oxide nanoparticles (TiO2-ZnO-MgO, TZM; CSTZM) at different concentrations (125, 250, and 500 μg mL−1) were investigated. The addition of nano-TZM promoted a color change (from colorless to white) in the film-forming solution, which increased its turbidity and it decreased viscosity. CSTZM were semitransparent (transmittance, T% decreased up to 49%) compared to CS-based films (T% = 95.5). CSTZM (particularly at a concentration of 500 μg mL−1) exhibited an improvement in the moisture content (decreased from 12.6 to 9.67%), water solubility (decreased from 14.94 to 10.22%), degree of swelling (increased from 19.79 to 36.28%), water vapor barrier (decreased from 6.62 x 10−16 to 4.33 x 10−16 g m−1 h−1 Pa−1), thermal stability (the endotherm peak increased from 99.5 to 157.7 °C), and mechanical properties (tensile strength and elongation at break increased from 4.15 to 4.98 kPa and 6.96 to 56.18%, respectively, while the modulus of elasticity decreased from 144 kPa to 4.11 kPa), without toxicity effects on Artemia salina (93.33% survival). X-ray diffraction and Fourier transform infrared studies demonstrated an interaction between CS-based films and nano-TZM. Overall, this film exhibited great potential for diverse industrial applications

Life’s Simple 7’s Cardiovascular Health Metrics are Associated with Hispanic/Latino Neurocognitive Function: HCHS/SOL Results

Hispanics/Latinos are purportedly at increased risk for neurocognitive decline and dementias. Without dementia cures, low-cost, well-tolerated public health means for mitigating neurocognitive decline are needed

Bioactive Components and Antioxidant and Antibacterial Activities of Different Varieties of Honey: A Screening Prior to Clinical Application

[EN]This study assessed 16 different honey samples in order to select the best one for therapeutic purposes. First, a study of honey's main bioactive compounds was carried out. Then phenolic profiles were determined and specific compounds quantified using a HPLC system coupled to a mass spectrometer. Then, antioxidant activity, by three in vitro methods, and antibacterial activity against reference strains and clinical isolates were evaluated. Great variability among samples was observed regarding ascorbic acid (between 0.34 ± 0.00 and 75.8 ± 0.41 mg/100 g honey; p < 0.001), total phenolic compounds (between 23.1 ± 0.83 and 158 ± 5.37 mg/100 g honey; p < 0.001), and total flavonoid contents (between 1.65 ± 0.11 and 5.93 ± 0.21 mg/100 g honey; p < 0.001). Forty-nine different phenolic compounds were detected, but only 46 of them were quantified by HPLC. The concentration of phenolic compounds and the phenolic profiles varied widely among samples (between 1.06 ± 0.04 and 18.6 ± 0.73 mg/100 g honey; p < 0.001). Antioxidant activity also varied significantly among the samples. All honey varieties exhibited antibacterial activity against both reference and clinical strains (effective concentrations ranged between 0.05 and 0.40 g/mL depending on the honey sample and bacteria tested). Overall, samples with better combinations of bioactive properties were avocado and chestnut honeys.SIThis work was supported by the Consejería de Sanidad of Junta de Castilla y Leon (Spain); under grant GRS 551/A/10. P.C.-F. was funded by the Consejería de Educacion of Junta de Castilla y Leon and European Social Fund.The authors are grateful to Isabel Fernandez Natal (Chief of the Clinical Microbiology Service in the University Assistance Complex of Leon, Spain) for providing us the clinical strains used in this work and drug susceptibility information

Hypospadias: a review

Hypospadias is a congenital malformation of the male external genitalia, which includes: anomalous location proximal to the urethral meatus, in any portion of the glans penis and perineum, hooded dorsal foreskin, and inverted penile curvature on the dorsal side of the foreskin. The etiology has been considered multifactorial, secondary to the interaction of environmental factors with specific genetic background. It represents the second most frequent congenital defect in male newborns. It has increasing prevalence rates of 0.25 new cases per 10,000 newborns per year. Risk factors that have been identified include infants small for gestational age with weight below the 10th percentile, head length and/or circumference, intrauterine growth restriction, and placental insufficiency. Regarding environmental risk factors, maternal exposure to pesticides has been linked. Prenatal diagnosis has been described, however proximal hypospadias is usually detected, making it difficult to diagnose distal hypospadias using this method. So usually the diagnosis is made after birth during the physical examination. To date, more than 300 surgical techniques are known for the correction of hypospadias. The treatment of distal hypospadias is currently performed in one time; the management of proximal hypospadias is controversial; one group favors the one-stage procedure, while other groups choose to perform the two-stage procedure