Search results for "character"
showing 10 items of 2956 documents
Solution-Based Processing for Scaffold Fabrication in Tissue Engineering Applications: A Brief Review
2021
The fabrication of 3D scaffolds is under wide investigation in tissue engineering (TE) because of its incessant development of new advanced technologies and the improvement of traditional processes. Currently, scientific and clinical research focuses on scaffold characterization to restore the function of missing or damaged tissues. A key for suitable scaffold production is the guarantee of an interconnected porous structure that allows the cells to grow as in native tissue. The fabrication techniques should meet the appropriate requirements, including feasible reproducibility and time- and cost-effective assets. This is necessary for easy processability, which is associated with the large …
Microstructural manipulation of electrospun scaffolds for specific bending stiffness for heart valve tissue engineering
2012
Biodegradable thermoplastic elastomers are attractive for application in cardiovascular tissue construct development due to their amenability to a wide range of physical property tuning. For heart valve leaflets, while low flexural stiffness is a key design feature, control of this parameter has been largely neglected in the scaffold literature where electrospinning is being utilized. This study evaluated the effect of processing variables and secondary fiber populations on the microstructure, tensile and bending mechanics of electrospun biodegradable polyurethane scaffolds for heart valve tissue engineering. Scaffolds were fabricated from poly(ester urethane) urea (PEUU) and the deposition…
Synthesis, characterization and foaming of PHEA-PLLA, a new graft copolymer for biomedical engineering
2014
Abstract In this study a chemical grafting procedure was set up in order to link high molecular weight poly L-lactic acid (PLLA) chains to the hydrophilic α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) backbone. A graft copolymer named PHEA-g-PLLA (or simply PHEA–PLLA) was obtained bearing a degree of derivatization of 1.0 mol.% of PLLA as grafted chain. This new hybrid derivative offers both the opportune crystallinity necessary for the production of scaffolds trough a thermally induced phase separation (TIPS) technique and the proper chemical reactivity to perform further functionalizations with bio-effectors and drugs. PHEA–PLLA porous scaffolds for tissue engineering applications were…
A facile method to determine pore size distribution in porous scaffold by using image processing
2015
Abstract Image processing permits scientists to investigate morphological properties of three-dimensional structures starting from their bi-dimensional gray-scale representation. In many cases porous structure with complex architecture has to be designed in order to attempt specific properties such in the case of scaffold for tissue engineering. Traditional morphological characterization, like scanning electron microscopy, should be coupled with quantitative information such as pore size distribution (PSD) in order to get a deeper understanding of the influence of the porous structure on tissue regeneration processes and on other related applications, it is remarkable to study a quantitativ…
Correlation between the Ionicity Character and the Charge Density in Semiconductors
1994
Using the electronic charge densities obtained by the empirical pseudopotential method for tetrahedrally bonded semiconductors, an ionicity scale is established that is in good agreement with the Phillips ionicity scale.
In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: A receiver operating characteristic analysis
2005
Objective To compare experimentally the image quality of charged-coupled device (CCD)-based digital, flatbed scanner digitized, and dental film radiographs. Study design High-contrast standardized radiographs of an aluminum step wedge containing boreholes were obtained on dental radiographic film (F) and a CCD receptor (D). Digitization (S) was done with a flatbed scanner. Each radiograph was separated into 23 single images, 18 of which showed a dark spot. Thirty observers indicated their confidence on the visibility of the spots for a receiver operating characteristic (ROC) analysis. Results Mean Az values (area beneath the ROC curves) differed significantly (P < .05), being highest for D …
On Obtaining Classification Confidence, Ranked Predictions and AUC with Tsetlin Machines
2020
Tsetlin machines (TMs) are a promising approach to machine learning that uses Tsetlin Automata to produce patterns in propositional logic, leading to binary (hard) classifications. In many applications, however, one needs to know the confidence of classifications, e.g. to facilitate risk management. In this paper, we propose a novel scheme for measuring TM confidence based on the logistic function, calculated from the propositional logic patterns that match the input. We then use this scheme to trade off precision against recall, producing area under receiver operating characteristic curves (AUC) for TMs. Empirically, using four real-world datasets, we show that AUC is a more sensitive meas…
Les compétences sociales : quels apports dans la compréhension des différences de réussite à l'école primaire ?
2016
This research aims at putting forward a measure and an identification of social competences in primary level, and to show the interest of the taking into account of these cross competences in the learning and in the achievement. It based on ultidisciplinary approach. It allows refining the tools as well conceptual as methodological being used to define and to measure social competences. To this extent, it will draw close connections between the work of scholars in areas beyond the strict sphere of educational research, including educational psychology, economics and the sociology of education with the common concern for reaching a better comprehension in the variability of school acquisitio…
The sleep of (scientific) reason produces (literary) monsters. : or, how science and literature shake hands
2016
La rao il·lustrada i la imaginacio romantica van ser vistes com dues maneres oposades de concebre l’art i la vida. Ara be, amb la perspectiva que ens atorga la historia, sembla dificil entendre l’una sense l’altra. Com si els malsons de la ciencia no fossin en el fons altra cosa que l’aliment dels monstres romantics. Aquest article analitza l’evolucio de la narrativa fantastica i el naixement de la narrativa cientifica en el segle xix, i l’enfrontament entre allo racional i allo sobrenatural.
Screening for Slow Reading Acquisition in Norway and Finland : a Quest for Context Specific Predictors
2020
Early identification of children at risk of developing reading difficulties is crucial for effective interventions. While orthographies and educational contexts differ, predictors included in early at-risk screening tend to remain rather homogeneous across countries. In this study, we compared longitudinal prediction patterns of being among the 20 percent lowest performing in reading fluency by the end of Grade 1 in Norway (N = 918) and Finland (N =378). The two countries differ in orthographic consistency (semi-transparent versus transparent), age at school entry and pre-primary education. Letter knowledge, phoneme isolation and rapid automatized naming (RAN) were unique predictors in the …