107 research outputs found
Horticultural Plant Residues as New Source for Lignocellulose Nanofibers Isolation: Application on the Recycling Paperboard Process
Horticultural plant residues (tomato, pepper, and eggplant) were identified as new sources for lignocellulose nanofibers (LCNF). Cellulosic pulp was obtained from the different plant residues using an environmentally friendly process, energy-sustainable, simple, and with low-chemical reagent consumption. The chemical composition of the obtained pulps was analyzed in order to study its influence in the nanofibrillation process. Cellulosic fibers were subjected to two different pretreatments, mechanical and TEMPO(2,2,6,6-Tetramethyl-piperidin-1-oxyl)-mediated oxidation, followed by high-pressure homogenization to produce different lignocellulose nanofibers. Then, LCNF were deeply characterized in terms of nanofibrillation yield, cationic demand, carboxyl content, morphology, crystallinity, and thermal stability. The suitability of each raw material to produce lignocellulose nanofibers was analyzed from the point of view of each pretreatment. TEMPO-mediated oxidation was identified as a more effective pretreatment to produce LCNF, however, it produces a decrease in the thermal stability of the LCNF. The different LCNF were added as reinforcing agent on recycled paperboard and compared with the improving produced by the industrial mechanical beating. The analysis of the papersheets’ mechanical properties shows that the addition of LCNF as a reinforcing agent in the paperboard recycling process is a viable alternative to mechanical beating, achieving greater reinforcing effect and increasing the products’ life cycles
Focused ion beam tomography of WC-Co cemented carbides
The microstructure of three different grades of WC-Co cemented carbides (hardmetals) has been reconstructed in three dimensions after sequential images obtained by focused ion beam. The three dimensional microstructual parameters are compared against the well-known two dimensional parameters of grain size, phase percentages and mean free path. Results show good agreement with the exception of individual grain recognition, which could not be univocally segmented. In the case of mean free path, the three-dimensional image depicts a more realistic description of the metal interconnections in the composite. Aiming for a simple example of direct application of these FIB tomography outcomes, reconstructed real microstructure for the coarser hardmetal grade studied was translated in a finite element modelling mesh, and elastic residual stresses were estimated from sintering to room temperature. Calculated thermal stresses agree with experimental results and show significant local variations in their value due to the complex microstructure of cemented carbides.Postprint (author's final draft
Primary health care medical curricula reflections and proposals from the present argentinean reality
Haciendo hincapié en la realidad argentina actual, el presente trabajo de opinión intenta contribuir, mediante
un conjunto de reflexiones argumentativas y de propuestas derivadas de ellas, con quienes planifican,
implementan y/o evalúan currículos médicos orientados hacia la Atención Primaria de la Salud. Los
interrogantes formulados, sustentados en referencias bibliográficas personas y generales, permiten perfilar
un panorama diagnóstico sobre la cuestión y establecer las consiguientes propuestas tentativas, dirigidas
hacia la superación de determinadas dificultades detectadas en la sociedad, los estudiantes, los
profesionales y los currículos médicos.Starting from the present Argentinean reality, this opinion paper intends to contribute, through a conjunct of
argumentative reflections and derived proposals, with planners, performers and evaluators of primary
health care medical curricula. Formulated questions, based on personal and general bibliographic
references, allow shaping a diagnostic landscape in this matter and the consequent and tentative proposals
to overcome determined difficulties detected in society, students, professionals and medical curricula
Scientific-technological culture and its relevance for medicine
La cultura científico-tecnológica posee singular relevancia para la Medicina, a la que provee imprescindible marco,
ya que al agregarse el adjetivo científico-tecnológico al sustantivo cultura se la refuerza y orienta esencialmente
en lo que se relaciona con la reflexión, la racionalidad, la aptitud crítica, el comportamiento ético, determinados
valores que hacen a las relaciones interpersonales y la toma de decisiones, competencias clave en totalidad para
dicha ciencia. En ese contexto e intentando dar debida cuenta de las varias relaciones existentes entre cultura
científico-tecnológica y Medicina, el presente trabajo: (a) analiza esta variedad cultural como parte significativa de
la cultura general, indispensable para los profesionales de la salud, y como depositaria de competencias referidas al
saber, saber ser y saber hacer, comunes con la docencia, investigación y/o práctica médicas, y (b) persigue efectuar
aportaciones, según un marco inicial de referencia, sobre los fundamentos, los variados modos y la finalidad de su
apropiación, registrando, también, emprendimientos de apropiación latinoamericanos y europeos en marcha que
ponen de relieve su utilidad recíproca.Scientific-technological culture has particular relevance for Medicine, to which an essential framework provides,
since the aggregation of the adjective scientific-technological to the noun culture, Medicine becomes singularly
reinforced and oriented in what concerns to reflection, rationality, critical skill, ethical behavior, defined values
related with interpersonal relationships and decision making, all of these key competences for that science. In
this context and intending to establish the varied relationships existing between scientific-technological culture
and culture, this paper: (a) analyzes this kind of culture as a significant part of the general culture, indispensable
for health professionals, and as a possessor of competences linked to knowledge, attitudes, habits, values and
cognitive and communicational skills, common to medical teaching, investigation and practice, and (b) pursues,
in accordance with a referential framework, to make contributions on the basis, different ways and purpose of its
social ownership, also registering current Latin American and European ownership initiatives as a demonstration
of its reciprocal utility. map in life support should be incorporated into the training curriculum for any student of
Degree of Medicine
Connectedness among herds of beef cattle bred under natural service
Background: A procedure to measure connectedness among herds was applied to a beef cattle population bred by natural service. It consists of two steps: (a) computing coefficients of determination (CDs) of comparisons among herds; and (b) building sets of connected herds. Methods: The CDs of comparisons among herds were calculated using a sampling-based method that estimates empirical variances of true and predicted breeding values from a simulated n-sample. Once the CD matrix was estimated, a clustering method that can handle a large number of comparisons was applied to build compact clusters of connected herds of the Bruna dels Pirineus beef cattle. Since in this breed, natural service is predominant and there are almost no links with reference sires, to estimate CDs, an animal model was used taking into consideration all pedigree information and, especially, the connections with dams. A sensitivity analysis was performed to contrast single-trait sire and animal model evaluations with different heritabilities, multiple-trait animal model evaluations with different degrees of genetic correlations and models with maternal effects. Results: Using a sire model, the percentage of connected herds was very low even for highly heritable traits whereas with an animal model, most of the herds of the breed were well connected and high CD values were obtained among them, especially for highly heritable traits (the mean of average CD per herd was 0.535 for a simulated heritability of 0.40). For the lowly heritable traits, the average CD increased from 0.310 in the single-trait evaluation to 0.319 and 0.354 in the multi-trait evaluation with moderate and high genetic correlations, respectively. In models with maternal effects, the average CD per herd for the direct effects was similar to that from single-trait evaluations. For the maternal effects, the average CD per herd increased if the maternal effects had a high genetic correlation with the direct effects, but the percentage of connected herds for maternal effects was very low, less than 12%. Conclusions: The degree of connectedness in a bovine population bred by natural service mating, such as Bruna del Pirineus beef cattle, measured as the CD of comparisons among herds, is high. It is possible to define a pool of animals for which estimated breeding values can be compared after an across-herds genetic evaluation, especially for highly heritable traits
Intravenous Cyclophosphamide Pulse Therapy in the Treatment of Systemic Sclerosis-Related Interstitial Lung Disease: A Long Term Study
Interstitial lung disease (ILD) frequently complicates systemic sclerosis (SSc). Cyclophosphamide (CYC) is a promising immunosuppressive therapy for SSc-related ILD. Our objective was to investigate the effectiveness of an intravenous CYC (iv CYC) pulse regime in SSc-related ILD during treatment and thereafter. In a prospective observational study ten consecutive patients with SSc-related ILD were treated with iv CYC in a pulse regime lasting from 6 to 24 months. Clinical status, pulmonary functional testing (PFT) and high resolution computed tomography (HRCT) of the chest were evaluated at enrolment and 6, 12 and 24 months thereafter. After treatment withdrawal, patients were followed up every 6 months with PFT and chest HRCT to monitor lung disease. Clinical improvement was apparent in 8 out of 10 patients. The median values of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and diffusion lung capacity for carbon monoxide (DLCO) as well as ground-glass pattern on HRCT did not change significantly after 6, 12 and 24 months of therapy. The follow-up continued in 8 out of 10 patients after treatment withdrawal for a median of 26.5 months (range: 12-48 months). The final median FVC was 54.5% of predicted value (interquartile range, IQR= 31.6%-94%). Only one patient suffered a FVC deterioration greater than 10%, even though less than 160 ml. The final median DLCO was 68% of predicted value (IQR=38.3-83.6%). Only 2 patients who developed pulmonary arterial hypertension deteriorated their DLCO values of more than 15%. An iv CYC pulse regimen over 24 months may stabilize pulmonary activity in patients with SSc-related ILD during the course of treatment and for a median of 26.5 months thereafter
Previous SARS-CoV-2 Infection Increases B.1.1.7 Cross-Neutralization by Vaccinated Individuals
With the spread of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is a need to assess the protection conferred by both previous infections and current vaccination. Here we tested the neutralizing activity of infected and/or vaccinated individuals against pseudoviruses expressing the spike of the original SARS-CoV-2 isolate Wuhan-Hu-1 (WH1), the D614G mutant and the B.1.1.7 variant. Our data show that parameters of natural infection (time from infection and nature of the infecting variant) determined cross-neutralization. Uninfected vaccinees showed a small reduction in neutralization against the B.1.1.7 variant compared to both the WH1 strain and the D614G mutant. Interestingly, upon vaccination, previously infected individuals developed more robust neutralizing responses against B.1.1.7, suggesting that vaccines can boost the neutralization breadth conferred by natural infection
Heterogeneous Infectivity and Pathogenesis of SARS-CoV-2 Variants Beta, Delta and Omicron in Transgenic K18-hACE2 and Wildtype Mice
The emerging SARS-CoV-2 variants of concern (VOCs) may display enhanced transmissibility, more severity and/or immune evasion; however, the pathogenesis of these new VOCs in experimental SARS-CoV-2 models or the potential infection of other animal species is not completely understood. Here we infected K18-hACE2 transgenic mice with B.1, B.1.351/Beta, B.1.617.2/Delta and BA.1.1/Omicron isolates and demonstrated heterogeneous infectivity and pathogenesis. B.1.351/Beta variant was the most pathogenic, while BA.1.1/Omicron led to lower viral RNA in the absence of major visible clinical signs. In parallel, we infected wildtype (WT) mice and confirmed that, contrary to B.1 and B.1.617.2/Delta, B.1.351/Beta and BA.1.1/Omicron can infect them. Infection in WT mice coursed without major clinical signs and viral RNA was transient and undetectable in the lungs by day 7 post-infection. In silico modeling supported these findings by predicting B.1.351/Beta receptor binding domain (RBD) mutations result in an increased affinity for both human and murine ACE2 receptors, while BA.1/Omicron RBD mutations only show increased affinity for murine ACE2
Implementing cost-optimal methodology in existing public buildings
This study presents some preliminary results of an on-going European Project, RePublic_ZEB, where an analysis is conducted for identifying the cost optimal levels for the existing buildings, towards nearly Zero Energy Buildings (nZEB) performance. The analysis is applied to the reference building for an existing office building in five different countries: Italy, Portugal, Romania, Spain and Greece. The evaluation tool uses a new cost optimization procedure based on a sequential search- optimization technique considering discrete options is applied and the results will be presented in terms of optimal “package of measures”, energy consumption and global costs. Finally a cross-country analysis will be performed
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