1,459 research outputs found
Effect of the anodization voltage on the porewidening rate of nanoporous anodic alumina
A detailed study of the pore-widening rate of nanoporous anodic alumina
layers as a function of the anodization voltage was carried out. The study
focuses on samples produced under the same electrolyte and concentration but
different anodization voltages within the self-ordering regime. By means of
ellipsometry-based optical characterization, it is shown that in the
porewidening process, the porosity increases at a faster rate for lower
anodization voltages. This opens the possibility of obtaining three-dimensional
nanostructured nanoporous anodic alumina with controlled thickness and
refractive index of each layer, and with a refractive index difference of up to
0.24 between layers, for samples produced with oxalic acid electrolytes
Development of RT-semi-nested PCR for detection of hepatitis A virus in stool in epidemic conditions.
The purpose of this study was to determine the efficiency of semi-nested PCR in detecting hepatitis A virus (HAV) RNA. During a 2-year period (1990-1991), HAV RNA was searched for in shellfish from the French Brittany coasts using cRNA and vRNA probes. In January 1992, at the time of a hepatitis A outbreak, 28 stool samples were collected from infected patients (18 adults, 10 children) with anti-HAV IgM. Four samples from subjects with negative HAV serology were used as negative controls. Nucleic acid amplification (reverse-transcription-semi-nested PCR) was performed to detect HAV in stool. HAV RNA was purified by phenol-chloroform extraction and converted to cDNA using reverse transcriptase (Mu-MLV). After amplification, PCR products were visualized on an ethidium-bromide-stained gel and confirmed by hybridization with a specific digoxigenin-labelled oligoprobe. Samples were also studied by molecular hybridization with cRNA and vRNA probes. After onset of the illness, HAV RNA was detected over a longer time period by semi-nested PCR (16/28) than by hybridization (0/28). Even though biological diagnosis of hepatitis A will continue to rely on the detection of anti-HAV IgM, PCR should be useful in certain clinical cases (diagnosis of relapse) and for epidemiological and environmental monitoring of viruses
Changing students' attitudes towards statistics through project-based learning in aerospace engineering
[EN] The application of project-based learning (PBL) in a course of statistics in the BSc. Degree in Aerospace Engineering at the Higher Technical School of Design Engineering at Universitat Politècnica de València has led to a significant and positive change in students¿ attitude towards learning and acquisition of statistical concepts. More specifically, PBL has provided the opportunity for students to overcome the limitations and preconceived barriers of classic learning methodologies and lectures, by applying statistical tools to improve the design of a cardboard glider.
The PBL strategy is implemented by means of a long-term project that is carried out in teams ranging from three to four students. The project is closely supervised by the laboratory lecturers, who act as mentors to the students throughout the whole term. At the initial stage, all the teams are given the same initial design of a cardboard glider, and students apply descriptive statistics to characterize and describe the flight of the original design. Then, students are given a flight benchmark that they should improve with their final designs. By applying inference, regression, and design of experiment tools, students modify the original design to beat the benchmark. The results of a survey that has been conducted suggest that, through this methodology, students not only apply and experiment with the concepts that they learn, but their motivation, engagement, and interest in statistics is also increased.The authors would like to thank the UPV and their support by funding this article with Education Improvement and Innovation Project (PIME-185).Trull, O.; Sempere-Ferre, F.; Martínez Alzamora, MN.; Sanchez-Anguix, V. (2021). Changing students' attitudes towards statistics through project-based learning in aerospace engineering. IATED Academy. 11540-11545. https://doi.org/10.21125/edulearn.2021.2416S115401154
Prediction of lung exposure to anti-tubercular drugs using plasma pharmacokinetic data: implications for dose selection
The development of novel candidate molecules for tuberculosis remains challenging, as drug distribution into the target tissue is not fully characterised in preclinical models of infection. Often antitubercular human dose selection is derived from pharmacokinetic data in plasma. Here, we explore whether whole-body physiologically-based pharmacokinetic (PBPK) modelling enables the prediction of lung exposure to anti-tubercular drugs in humans. Whole-body PBPK models were developed for rifampicin, isoniazid, pyrazinamide, and ethambutol using plasma data in mice as basis for the prediction of lung exposure. Model parameters were subsequently used to extrapolate disposition properties from mouse and determine lung:plasma ratio in humans. Model predictions were compared to biopsy data from patients. Predictions were deemed adequate if they fell within two-fold range of the observations. The concentration vs time profiles in lung were adequately predicted in mice. Isoniazid and pyrazinamide lung exposures were predicted to be comparable to plasma levels, whereas ethambutol lung exposure was predicted to be higher than in plasma. Lung:plasma ratio in humans could be reasonably predicted from preclinical data, but was highly dependent on the distribution model. This analysis showed that plasma pharmacokinetics may be used in conjunction with PBPK modelling to derive lung tissue exposure in mice and humans during early lead optimisation phase. However, the impact of uncertainty in predicted tissue exposure due to distribution should be always investigated through a sensitivity analysis when only plasma data is available. Despite these limitations, insight into lung tissue distribution represents a critical step for the dose rationale in tuberculosis patients
Adaptation of a project of teaching innovation in the subject of statistics in the degree of aerospace engineering in times of COVID-19
[EN] The rapid spread of the SARSCoV-2 virus (COVID-19) in Spain caused a general lockdown of the
population at home for 44 days. Due to this, lecturers had to design new learning strategies, adapted to
the general lockdown, to deliver content and learning materials. The goal of this work is to describe and
analyze the adaptation carried out in a teaching innovation project at the Statistics course at BSc. in
Aerospace Engineering. The project involves students participating in project-based learning. The
adaptation of the project-based learning activity aimed to tackle the obstacles and particularities of the
lockdown period. A total of 118 students participated in the activities, with all of them positively evaluating
the experience and adaptation carried out. 92.6% of the students considered that, after participating in
the project, they improved their critical thinking and creativity. In addition, 88.8% suggested that their
innovation skills improved. Overall, the students showed a high degree of engagement and motivation.The authors would like to thank the Universitat Politècnica de València and their support by funding this
article with Education Improvement and Innovation Project (PIME-185).Sempere-Ferre, F.; Trull, O.; Soler Torro, JM.; Conchado Peiró, A. (2021). Adaptation of a project of teaching innovation in the subject of statistics in the degree of aerospace engineering in times of COVID-19. IATED Academy. 11553-11557. https://doi.org/10.21125/edulearn.2021.2418S115531155
P18-01. Exquisite specificity of CTL response to the M184V mutation
International audiencen.
Direct sequencing of hepatitis A virus strains isolated during an epidemic in France
Direct sequencing of PCR products was used to study the VP1 region of the hepatitis A virus (HAV) genome (position 2199 to 2356) of nine strains isolated from human stools collected during a hepatitis A epidemic (western France, 1992), three strains from environmental samples (1990, 1991, and 1992), and two HAV cell culture isolates (the French strain CF53/Lyon and strain CLF). These viruses differed from CF53/Lyon (genotype I) by between 1 and 10.3%, and results indicated the existence of two groups of strains belonging to two different subgenotypes (IA and IB). With this sequencing technique it was possible to monitor the epidemiology of HAV and study its relations
Scaling properties of the critical behavior in the dilute antiferromagnet Fe(0.93)Zn(0.07)F2
Critical scattering analyses for dilute antiferromagnets are made difficult
by the lack of predicted theoretical line shapes beyond mean-field models.
Nevertheless, with the use of some general scaling assumptions we have
developed a procedure by which we can analyze the equilibrium critical
scattering in these systems for H=0, the random-exchange Ising model, and, more
importantly, for H>0, the random-field Ising model. Our new fitting approach,
as opposed to the more conventional techniques, allows us to obtain the
universal critical behavior exponents and amplitude ratios as well as the
critical line shapes. We discuss the technique as applied to
Fe(0.93)Zn(0.07)F2. The general technique, however, should be applicable to
other problems where the scattering line shapes are not well understood but
scaling is expected to hold.Comment: 17 pages, 5 figure
An Aza-Fused pi-Conjugated Microporous Framework Catalyzes the Production of Hydrogen Peroxide
"This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/page/policy/articlesonrequest/index.html"[EN] In order to produce hydrogen peroxide in small-scale electrochemical plants, selective catalysts for the oxygen reduction reaction (ORR) toward the desired species are required. Here, we report about the synthesis, characterization, ORR electrochemical behavior, and reaction mechanism of an aza-fused pi-conjugated microporous polymer, which presents high selectivity toward hydrogen peroxide. It was synthesized by polycondensation of 1,2,4,5-benzenetetramine tetrahydrochloride and triquinoyl octahydrate. A cobalt-modified version of the material was also prepared by a simple postsynthesis treatment with a Co(II) salt. The characterization of the material is consistent with the formation of a conductive robust porous covalent laminar polyaza structure. The ORR properties of these catalysts were investigated using rotating disk and rotating disk ring arrangements. The results indicate that hydrogen peroxide is almost exclusively produced at very low overpotentials on these materials. Density functional theory calculations provide key elements to understand the reaction mechanism. It is found that, at the relevant potential for the reaction, half of the nitrogen atoms of the material would be hydrogenated. This hydrogenation process would destabilize some carbon atoms in the lattice and would provide segregated charge. On the destabilized carbon atoms, molecular oxygen would be chemisorbed with the aid of charge transferred from the hydrogenated nitrogen atoms and solvation effects. Due to the low destabilization of the carbon sites, the resulting molecular oxygen chemisorbed state, which would have the characteristics of a superoxide species, would be only slightly stable, promoting the formation of hydrogen peroxide.This work has been financially supported by the MCINN-FEDER (projects CTQ2016-76221-P, MAT2013-46753-C2-1-P, and MAT2014-52305-P) and Generalitat Valenciana (project PROMETEO/2014/013).Briega-Martos, V.; Ferre Vilaplana, A.; De La Peña, A.; Segura, J.; Zamora, F.; Feliu, J.; Herrero, E. (2017). An Aza-Fused pi-Conjugated Microporous Framework Catalyzes the Production of Hydrogen Peroxide. ACS Catalysis. 7(2):1015-1024. https://doi.org/10.1021/acscatal.6b03043S101510247
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