Modelling the motion of a cell population in the extracellular matrix

The paper aims at describing the motion of cells in fibrous tissues taking into account of the interaction with the network fibers and among cells, of chemotaxis, and of contact guidance from network fibers. Both a kinetic model and its continuum limit are described

Stiff Polymers, Foams and Fiber Networks

We study the elasticity of fibrous materials composed of generalized stiff polymers. It is shown that in contrast to cellular foam-like structures affine strain fields are generically unstable. Instead, a subtle interplay between the architecture of the network and the elastic properties of its building blocks leads to intriguing mechanical properties with intermediate asymptotic scaling regimes. We present exhaustive numerical studies based on a finite element method complemented by scaling arguments.Comment: 4 pages, 5 figure

Floppy modes and non-affine deformations in random fiber networks

We study the elasticity of random fiber networks. Starting from a microscopic picture of the non-affine deformation fields we calculate the macroscopic elastic moduli both in a scaling theory and a self-consistent effective medium theory. By relating non-affinity to the low-energy excitations of the network (``floppy-modes'') we achieve a detailed characterization of the non-affine deformations present in fibrous networks.Comment: 4 pages, 2 figures, new figure

Tissue compatibility of poly(hydroxypropylglutamate)-prazosin conjugates

Biocompatibility of an injectable biodegradable drug delivery system for prazosin was investigated in Sprague-Dawley rats by histological studies after subcutaneous injection ofpoly(hydroxypropyl glutamate)-prazosin (PHPG-prazosin) conjugate particles. The studies showed that (1) the acute inflammatory response to this injectable biodegradable polymeric prodrug system was mild and of only short duration, (2) the chronic inflammation was minimal to zero, (3) the fibrous capsule could be seen starting from 7 days and became more prominent at longer time periods, (4) a collagen network was formed into the injection site after 21 days, (5) the macrophages and foreign giant cells reacted to the globules of conjugate particles, and (6) no adverse reactions were identified. Focal inflammation and the formation of the fibrous capsule around the injection site were the significant histological findings in the histopathological studies. Therefore, it is concluded that the biodegradable injectable PHPG-prazosin carbamate polymeric prodrug system is tissue biocompatible

PRED-CLASS: cascading neural networks for generalized protein classification and genome-wide applications

A cascading system of hierarchical, artificial neural networks (named PRED-CLASS) is presented for the generalized classification of proteins into four distinct classes-transmembrane, fibrous, globular, and mixed-from information solely encoded in their amino acid sequences. The architecture of the individual component networks is kept very simple, reducing the number of free parameters (network synaptic weights) for faster training, improved generalization, and the avoidance of data overfitting. Capturing information from as few as 50 protein sequences spread among the four target classes (6 transmembrane, 10 fibrous, 13 globular, and 17 mixed), PRED-CLASS was able to obtain 371 correct predictions out of a set of 387 proteins (success rate approximately 96%) unambiguously assigned into one of the target classes. The application of PRED-CLASS to several test sets and complete proteomes of several organisms demonstrates that such a method could serve as a valuable tool in the annotation of genomic open reading frames with no functional assignment or as a preliminary step in fold recognition and ab initio structure prediction methods. Detailed results obtained for various data sets and completed genomes, along with a web sever running the PRED-CLASS algorithm, can be accessed over the World Wide Web at http://o2.biol.uoa.gr/PRED-CLAS

Force-induced recruitment of cten along keratin network in epithelial cells.

The cytoskeleton provides structural integrity to cells and serves as a key component in mechanotransduction. Tensins are thought to provide a force-bearing linkage between integrins and the actin cytoskeleton; yet, direct evidence of tensin's role in mechanotransduction is lacking. We here report that local force application to epithelial cells using a micrometer-sized needle leads to rapid accumulation of cten (tensin 4), but not tensin 1, along a fibrous intracellular network. Surprisingly, cten-positive fibers are not actin fibers; instead, these fibers are keratin intermediate filaments. The dissociation of cten from tension-free keratin fibers depends on the duration of cell stretch, demonstrating that the external force favors maturation of cten-keratin network interactions over time and that keratin fibers retain remarkable structural memory of a cell's force-bearing state. These results establish the keratin network as an integral part of force-sensing elements recruiting distinct proteins like cten and suggest the existence of a mechanotransduction pathway via keratin network

A proof of concept on real-time air quality monitoring system

According to the Department of Environment Malaysia, Air Pollutant Index (API) is an indicator for the air quality status at any particular area. API is calculated based on average concentration of air pollutants such as Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Carbon Monoxide (CO), ground level Ozone (O3) and particulate matter (PM10), each over their respective period of averaging time. A sub-index for each pollutant is determined separately based on a predetermined standard and the highest sub- index is used as the API (Department of Environment Malaysia, 2000). The United States Environmental Protection Agency (US EPA) (2010) defines PM10 as "Inhalable coarse particles," such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter (United States Environmental Protection Agency, 2010). Typically, the concentration PM10 is the highest among all pollutants in Malaysia and therefore it determines the API value (APIMS DOE Malaysia, 2015)