Student-Generated Videos to Promote Understanding of Chemical Reactions

Published as part of the Journal of Chemical Education virtual special issue “Teaching Changes and Insights Gained in the Time after COVID-19”.[Abstract] Students were tasked with the creation of videos of ordinary reactions to promote significant learning of complex concepts underlying chemical transformations. Interactive infographics were used to deliver instructions. Afterward, students planned the experimental setup for the reaction execution and video recording using their mobile phones. The videos and an online questionnaire, also created by the students, were shared with other class members using the visual platform Padlet. The reasoning required to elaborate the questions contributed to a better understanding of the principles underpinning the chemical equation. An exit survey showed that planning and performing the activity were not time-consuming for the students. Marks attained by the students in questions related to chemical reactions improved after completing the activity

Treatment of bilateral hyperplasia of the coronoid process of the mandible : Presentation of a case and review of the literature

Bilateral hyperplasia of the coronoid process is infrequent. It consists of an elongation of the coronoid process of the mandible and is, accordingly, a mechanical problem, limiting mouth opening. This article looks at the case of a 28 year-old male with significant limitation on opening his mouth, secondary to bilateral hyperplasia of the coronoid process. We reviewed the literature and analysed the diagnostic and therapeutic procedures used, paying special attention to the surgical approaches to the coronoid process and emphasising the importance of early post-operative rehabilitation, describing our experience with the TheraBite® (Atos Medical AB, PO Box 183, 242 22 Hörby, Sweden). The satisfactory result of the procedure is marked by the stable recovery of the mouth opening, achieved by a good combination of surgical and physiotherapeutic techniques

Prevalence of human bocavirus infections in Europe. A systematic review and meta-analysis

Human bocaviruses (HBoVs) are recently described as human emergent viruses, especially in young children. In this study, we undertook a systematic review and meta-analysis to estimate their prevalence in Europe. PubMed, Web of Science and Scopus databases were systematically screened for clinical studies, up to October 2020. Study eligibility criteria were primary full-text articles from clinical studies, conducted using valid screening test methods and published in peer-reviewed journals, in English or Spanish and from European countries. The overall pooled prevalence, prevalence by country as well as the prevalence of HBoV as a single or co-pathogen were estimated using a random-effects model. Sub-group and meta-regression analyses explored potential sources of heterogeneity in the data. A total of 35 studies involving 32,656 subjects from 16 European countries met the inclusion criteria. Heterogeneity (I2 = 97.0%, p < .01) was seen among studies; HBoV prevalence varied from 2.0 to 45.69% with a pooled estimate of 9.57% (95%CI 7.66-11.91%). The HBoV prevalence both as a single infection (3.99%; 95%CI 2.99-5.31%) or as co-infection with other viruses (5.06%; 95%CI 3.88-6.58%) was also analysed. On a geographic level, prevalence by country did not show statistical differences, ranging from 3.24% (Greece) to 21.05% (Denmark). An odds ratio analysis was also included in order to evaluate the relevance of the variable ‘age’ as a risk factor of HBoV infection in children <5 years old. The OR value of 1.77 (95%CI 1.13-2.77; p < .01) indicated that being <5 years old is a risk factor for HBoV infection. This study showed that HBoV has a moderate prevalence among European countriesThis study was partly supported by Grant ED431C 2018/18 from the Consellería de Educación, Universidade e Formación Profesional, Xunta de Galicia (Spain)S

Design of asymptotically optimal improper constellations with hexagonal packing

This paper addresses the problem of designing asymptotically optimal improper constellations with a given circularity coefficient (correlation coefficient between the constellation and its complex conjugate). The designed constellations are optimal in the sense that, at high signal-to-noise-ratio (SNR) and for a large number of symbols, yield the lowest probability of error under an average power constraint for additive white Gaussian noise channels. As the number of symbols grows, the optimal constellation is the intersection of the hexagonal lattice with an ellipse whose eccentricity determines the circularity coefficient. Based on this asymptotic result, we propose an algorithm to design finite improper constellations. The proposed constellations provide significant SNR gains with respect to previous improper designs, which were generated through a widely linear transformation of a standard M-ary quadrature amplitude modulation constellation. As an application example, we study the use of these improper constellations by a secondary user in an underlay cognitive radio network.The work of Jesús A. López-Fernández and R. G. Ayestarán was partly supported by the Ministerio de Ciencia, Innovación y Universidades under project TEC2017-86619-R (ARTEINE), and by the Gobierno del Principado de Asturias under project GRUPIN-IDI2018-000191. The work of I. Santamaria was partly supported by the Ministerio de Economía y Competitividad (MINECO) of Spain, and AEI/FEDER funds of the E.U., under grant TEC2016-75067-C4-4-R (CARMEN) and TEC2015-69648-REDC (Red COMONSENS). The work of C. Lameiro was supported by the German Research Foundation (DFG) under grant LA 4107/1-1

Human sapovirus among outpatients with acute gastroenteritis in Spain: a one-year study

Viral agents of human gastroenteritis affect people of all ages across the globe. As a mainly self-limiting disease, it is difficult to evaluate the real prevalence of etiological agents circulating in each region. Many of the analyzed outbreaks are caused by viruses of the family Caliciviridae, especially the genus Norovirus (NoV). Most studies have focused on other enteric viruses, leaving sapovirus (SaV) underestimated as an important emerging human threat. This one-year study analyzed clinical samples from hospital outpatients with acute gastroenteritis in Spain, with the aim of revealing the importance of human SaV as an emerging viral pathogen. A total of 2667 stools were tested using reverse transcription (RT)-qPCR to detect and quantify SaV. Sapovirus was detected in all age groups, especially in infants, children, and the elderly. The prevalence was 15.64% (417/2667), and was slightly higher in 0–2- and 3–5-year-olds (19.53% and 17.95%, respectively) and much lower in 13–18-year-olds (9.86%). Positive samples were detected throughout the year, with peaks of detection during autumn and the late winter to early spring months. The mean value for the quantified samples was 6.5 × 105 genome copies per gram of stool (GC/g) (range 2.4 × 103–6.6 × 1011 GC/g). RT-nested PCR and sequencing were used for further genotyping. Genetic characterization showed a predominance of genogroup I (GI), followed by GII and GIV. The detection of multiple genotypes suggests the circulation of different strains without any clear tendency. The results obtained suggest SaV as the second major gastroenteritis agent after NoV in the region.This work was supported in part by grant 2014-PG110 from the Xunta de Galicia (Spain)S

Magnetic reduced graphene oxide/nickel/platinum nanoparticles micromotors for mycotoxin analysis

Magnetic reduced graphene oxide/nickel/platinum nanoparticles (rGO/Ni/PtNPs) micromotors for mycotoxin analysis in food samples were developed for food-safety diagnosis. While the utilization of self-propelled micromotors in bioassays has led to a fundamentally new approach, mainly due to the greatly enhanced target?receptor contacts owing to their continuous movement around the sample and the associated mixing effect, herein the magnetic properties of rGO/Ni/PtNPs micromotors for mycotoxin analysis are additionally explored. The micromotor-based strategy for targeted mycotoxin biosensing focused on the accurate control of micromotor-based operations: 1) on-the-move capture of free aptamers by exploiting the adsorption (outer rGO layer) and catalytic (inner PtNPs layer) properties and 2) micromotor stopped flow in just 2 min by exploiting the magnetic properties (intermediate Ni layer). This strategy allowed fumonisin B1 determination with high sensitivity (limit of detection: 0.70 ngmL@1) and excellent accuracy (error: 0.05% in certified reference material and quantitative recoveries of 104:4% in beer) even in the presence of concurrent ochratoxin A (105?108:8% in wines). These results confirm the developed approach as an innovative and reliable analytical tool for food-safety monitoring, and confirm the role of micromotors as a new paradigm in analytical chemistry.Ministerio de Economía y CompetitividadComunidad de Madri

Aerodynamic optimization of propellers for High Altitude Pseudo-Satellites

[EN] The propulsion system of High-Altitude Platform Stations or High-Altitude Pseudo-Satellites (HAPS) is commonly based on propellers. The properties of the atmosphere at those high altitudes and the characteristic speed of HAPS entail that the flight is performed at very low Reynolds numbers. Hence, the aerodynamic behavior of the propeller sections changes substantially from the hub to the tip of the blades. Under those circumstances, the ordinary methods to develop optimized propellers are not useful and must be modified. We present a method of propeller design adapted to HAPS features. It combines traditional solutions with modern numerical tools. Specifically, Theodorsen analytical theory is used to minimize induced drag. This process leaves one free parameter that it is fixed optimizing a cost function depending on the Reynolds number with a viscous-potential numerical code. It leads to an optimal determination of the geometrical characteristics of the propeller, i.e., chord and pitch distribution, increasing its total efficiency. The resulting algorithm has low computational requirements what makes it very appropriate for the preliminary design of HAPS missions, when it is necessary to simulate many different cases. That methodology has been applied to a relatively small HAPS airship with a wind speed of 10 m/s and required thrust of 100 N. The propeller is assumed to be made up of NACA4412 airfoils and the cost function to be minimized is given by the ratio of the 2D drag and lift coefficients. With those conditions we perform a parametric analysis where different combinations of diameters, thrust coefficients, and propeller advance ratios are considered. Over a Reynolds number range from 103 to 106, the new method provides a gain about 5% in the propeller efficiency when compared with the ordinary design procedure that employs a constant Reynolds number. That gain is of utmost importance for HAPS operations, since, for example, it allows an increase in the payload of up to 25% for a 90 meters long airship.S

Polymer-based micromotors fluorescence immunoassay for on the move sensitive procalcitonin determination in very low birth weight infants' plasma

A new fluorescence micromotor-based immunoassay (FMIm) has been developed forvprocalcitonin (PCT) determination as an early sepsis diagnostic analytical tool. The micromotorsvcombine the high binding capacity of the specific antibodies onto their polymeric polypyrrole outervlayer (PPy layer), with their magnetic guidance (Ni layer) and self-propulsion by catalytic generationvof oxygen bubbles (PtNP inner layer) to actively recognize the PCT antigen. This FMIm allowed avsensitive (LOD = 0.07 ng mL?1) and direct PCT determination in clinical samples from very lowbirth-vweight infants (VLBWI) with sepsis suspicion, using small volumes of sample (25 ?L) in a clinically relevant range of concentrations (0.5?150 ng mL?1). The good agreement between PCTvlevels obtained by our micromotor-based method and routine immunofluorescence hospitalvdetermination demonstrates the feasibility for the analysis in VLBWI samples and its potential as avpoint-of-care diagnostic tool for sepsis.Ministerio de Economía, Industria y Competitividad); Comunidad de Madrid; La Caix

On the capabilities and limitations of high altitude pseudo-satellites

[EN] The idea of self-sustaining air vehicles that excited engineers in the seventies has nowadays become a reality as proved by several initiatives worldwide. High altitude platforms, or Pseudo-satellites (HAPS), are unmanned vehicles that take advantage of weak stratospheric winds and solar energy to operate without interfering with current commercial aviation and with enough endurance to provide long-term services as satellites do. Target applications are communications, Earth observation, positioning and science among others. This paper reviews the major characteristics of stratospheric flight, where airplanes and airships will compete for best performance. The careful analysis of involved technologies and their trends allow budget models to shed light on the capabilities and limitations of each solution. Aerodynamics and aerostatics, structures and materials, propulsion, energy management, thermal control, flight management and ground infrastructures are the critical elements revisited to assess current status and expected short-term evolutions. Stratospheric airplanes require very light wing loading, which has been demonstrated to be feasible but currently limits their payload mass to few tenths of kilograms. On the other hand, airships need to be large and operationally complex but their potential to hover carrying hundreds of kilograms with reasonable power supply make them true pseudo-satellites with enormous commercial interest. This paper provides useful information on the relative importance of the technology evolutions, as well as on the selection of the proper platform for each application or set of payload requirements. The authors envisage prompt availability of both types of HAPS, aerodynamic and aerostatic, providing unprecedented services.SIEuropean Space Agenc

Prussian Blue/Chitosan Micromotors with Intrinsic Enzyme-like Activity for (bio)-Sensing Assays

Prussian Blue (PB)/chitosan enzyme mimetic tubular micromotors are used here for on-the-fly (bio)-sensing assays. The micromotors are easily prepared by direct deposition of chitosan into the pores of a membrane template and in situ PB synthesis during hydrogel deposition. Under judicious pH control, PB micromotors display enzyme mimetic capabilities with three key functions on board: the autonomous oxygen bubble propulsion (with PB acting as a catalase mimic for hydrogen peroxide decomposition), 3,3',5,5'-tetramethylbenzidine (TMB) oxidation (with PB acting as a peroxidase mimic for analyte detection), and as a magnetic material (to simplify the (bio)-sensing steps). In connection with chitosan capabilities, these unique enzyme mimetic micromotors are further functionalized with acetylthiocholinesterase enzyme (ATChE) to be explored in fast inhibition assays (20 min) for the colorimetric determination of the nerve agent neostigmine, with excellent analytical performance in terms of quantification limit (0.30 mu M) and concentration linear range (up to 500 mu M), without compromising efficient micromotor propulsion. The new concept illustrated holds considerable potential for a myriad of (bio)-sensing applications, including forensics, where this conceptual approach remains to be explored. Micromotor-based tests to be used in crime scenes are also envisioned due to the reliable neostigmine determination in unpretreated samples.Ministerio de Economía, Industria y CompetitividadComunidad de MadridEuropean Commissio