Author Correction: Preparation and modeling of three‐layered PCL/PLGA/PCL fibrous scaffolds for prolonged drug release (original) (raw)
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Preparation and modeling of three‐layered PCL/PLGA/PCL fibrous scaffolds for prolonged drug release
Scientific Reports
The authors present the preparation procedure and a computational model of a three‐layered fibrous scaffold for prolonged drug release. The scaffold, produced by emulsion/sequential electrospinning, consists of a poly(d,l-lactic-co-glycolic acid) (PLGA) fiber layer sandwiched between two poly(ε-caprolactone) (PCL) layers. Experimental results of drug release rates from the scaffold are compared with the results of the recently introduced computational finite element (FE) models for diffusive drug release from nanofibers to the three-dimensional (3D) surrounding medium. Two different FE models are used: (1) a 3D discretized continuum and fibers represented by a simple radial one-dimensional (1D) finite elements, and (2) a 3D continuum discretized by composite smeared finite elements (CSFEs) containing the fiber smeared and surrounding domains. Both models include the effects of polymer degradation and hydrophobicity (as partitioning) of the drug at the fiber/surrounding interface. Th...
A Computational Model for Drug Release from PLGA Implant
Materials, 2018
Due to the relative ease of producing nanofibers with a core–shell structure, emulsion electrospinning has been investigated intensively in making nanofibrous drug delivery systems for controlled and sustained release. Predictions of drug release rates from the poly (d,l-lactic-co-glycolic acid) (PLGA) produced via emulsion electrospinning can be a very difficult task due to the complexity of the system. A computational finite element methodology was used to calculate the diffusion mass transport of Rhodamine B (fluorescent drug model). Degradation effects and hydrophobicity (partitioning phenomenon) at the fiber/surrounding interface were included in the models. The results are validated by experiments where electrospun PLGA nanofiber mats with different contents were used. A new approach to three-dimensional (3D) modeling of nanofibers is presented in this work. The authors have introduced two original models for diffusive drug release from nanofibers to the 3D surrounding medium ...
Dominant-negative mutations in the DNA-binding domain of STAT3 cause hyper-IgE syndrome
Nature, 2007
1 Aaron, F. D.; Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Martin, M. Aldaya; Alexa, C.; Alimujiang, K.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Antunovic, B.; Arneodo, M.; Asmone, A.; Aushev, V.; Bachynska, O.; Backovic, S.; Baghdas Multi-leptons with high transverse momentum at HERA JOURNAL OF HIGH ENERGY PHYSICS Article [Aaron, F. D.; Alexa, C.; Antonov, A.; Morris, J. D.; Panagoulias, I.; Papadopoulou, Th.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R.] NIPNE, ; Alimujiang, K.; Andreev, V.; Antunovic, B.; Asmone, A.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J. C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, A precision measurement of the inclusive ep scattering cross section at HERA EUROPEAN PHYSICAL JOURNAL C Article [Aaron, F. D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.
Heart Mechanical Model Based on Holzapfel Experiments
Learning and Analytics in Intelligent Systems
We have formulated orthotropic material model for human heart tissue based on experimental investigation of passive material properties of myocardium [1]. The Cauchy stress/stretch and shear stress/amount of shear relation curves are used, which are established experimentally under different loading conditions: biaxial extension and triaxial shear. The averaged curves obtained from all considered specimens in [1] are reconstructed and used in our FE computational model. A computational procedure for determination of stresses for current stretches and amounts of shear at integration points of the FE model is implemented in the code PAK. Compressibility condition is imposed to couple the normal stresses using a penalty formulation. Applicability and reliability of this material model is tested on simple 3D models and on a heart wall segment under passive conditions. This numerical model offers an accurate description of the ventricular mechanics and can be used in studying heart problems in order to improve medical treatment of heart diseases.
Frontiers in Bioengineering and Biotechnology
Mass transport represents the most fundamental process in living organisms. It includes delivery of nutrients, oxygen, drugs, and other substances from the vascular system to tissue and transport of waste and other products from cells back to vascular and lymphatic network and organs. Furthermore, movement is achieved by mechanical forces generated by muscles in coordination with the nervous system. The signals coming from the brain, which have the character of electrical waves, produce activation within muscle cells. Therefore, from a physics perspective, there exist a number of physical fields within the body, such as velocities of transport, pressures, concentrations of substances, and electrical potential, which is directly coupled to biochemical processes of transforming the chemical into mechanical energy and further internal forces for motion. The overall problems of mass transport and electrophysiology coupled to mechanics can be investigated theoretically by developing appropriate computational models. Due to the enormous complexity of the biological system, it would be almost impossible to establish a detailed computational model for the physical fields related to mass transport, electrophysiology, and coupled fields. To make computational models feasible for applications, we here summarize a concept of smeared physical fields, with coupling among them, and muscle mechanics, which includes dependence on the electrical potential. Accuracy of the smeared computational models, also with coupling to muscle mechanics, is illustrated with simple example, while their applicability is demonstrated on a liver model with tumors present. The last example shows that the introduced methodology is applicable to large biological systems.
Finite Element Models with Smeared Fields Within Tissue – A Review of the Current Developments
Learning and Analytics in Intelligent Systems
In this review we present the current stage and developments in the finite element modeling of mass transport by the smeared concept, introduced and conducted by the first author over several years. The basis of this methodology represents the formulation of a composite smeared finite element (CSFE). The CSFE consists of domains which can be at different length scale, where we have separate physical fields for each of the domains and with the corresponding governing laws. The continuum domains within the CSFE also include 1D transport represented in a continuum form by the appropriate transport tensors. The fields are coupled by the connectivity elements at each node, representing transport properties of the walls separating the domains. Formulation of this methodology and applications on various biomedical problems have been published in a number of recent publications. Here, we give an overview of these achievements and show some results of the current research.
Optical and aromaticity properties of sumanene modified with boron and nitrogen atoms; a DFT study
Changes of optical and aromaticity properties of sumanene resulting from substitution of its benyzlic positions with boron and nitrogen atoms were investigated by means of density functional theory (DFT) computations. The aim of this study was to confirm that various important properties for the practical application of sumanene can be finely tuned in the described manner. It was shown that non-linear optical (NLO) properties (polarizabilities and hyperpolarizabilities), exciton binding energies, dielectric constant and nucleus independent chemical shifts (NICS) of sumanene buckybowl are significantly influenced by substitution of its benzylic carbon atoms.
Modeling buckybowls with semi-empirical levels of theory
Typical representatives of buckybowls (also known as molecular bowls or π-bowls), corannulene and sumanene were investigated employing semi-empirical levels of theory and the obtained results were compared with the results obtained within Hartree-Fock (HF) and density functional theory (DFT) computations. The purpose of this study was to conclude to what extent computationally inexpensive semi-empirical levels of theory can be used for the modeling of buckybowls. Obtained results indicate that semi-empirical levels of theory are reliable tool when it comes to the initial investigation of buckybowls.
Computers in Biology and Medicine, 2019
Basic functions of living organisms are governed by the nervous system through bidirectional signals transmitted from the brain to neural networks. These signals are similar to electrical waves. In electrophysiology the goal is to study the electrical properties of biological cells and tissues, and the transmission of signals. From a physics perspective, there exists a field of electrical potential within the living body, the nervous system, extracellular space and cells. Electrophysiological problems can be investigated experimentally and also theoretically by developing appropriate mathematical or computational models. Due to the enormous complexity of biological systems, it would be almost impossible to establish a detailed computational model of the electrical field, even for only a single organ (e.g. heart), including the entirety of cells comprising the neural network. In order to make computational models feasible for practical applications, we here introduce the concept of smeared fields, which represents a generalization of the previously formulated multiscale smeared methodology for mass transport in blood vessels, lymph, and tissue. We demonstrate the accuracy of the smeared finite element computational models for the electric field in numerical examples. The electrical field is further coupled with ionic mass transport within tissue composed of interstitial spaces extracellularly and by cytoplasm and organelles intracellularly. The proposed methodology, which couples electrophysiology and molecular ionic transport, is applicable to a variety of biological systems.
Frontiers in Medical Technology, 2021
Bioresorbable vascular scaffolds (BVS), made either from polymers or from metals, are promising materials for treating coronary artery disease through the processes of percutaneous transluminal coronary angioplasty. Despite the opinion that bioresorbable polymers are more promising for coronary stents, their long-term advantages over metallic alloys have not yet been demonstrated. The development of new polymer-based BVS or optimization of the existing ones requires engineers to perform many very expensive mechanical tests to identify optimal structural geometry and material characteristics. in silico mechanical testing opens the possibility for a fast and low-cost process of analysis of all the mechanical characteristics and also provides the possibility to compare two or more competing designs. In this study, we used a recently introduced material model of poly-l-lactic acid (PLLA) fully bioresorbable vascular scaffold and recently empowered numerical InSilc platform to perform in...