Wojciech Czaja

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Microbial cellulose has proven to be a remarkably versatile biomaterial and can be used in wide variety of applied scientific endeavors, such as paper products, electronics, acoustics, and biomedical devices. In fact, biomedical devices recently have gained a significant amount of attention because of an increased interest in tissue-engineered products for(More)
Structural characteristics of microbial cellulose synthesized by two different methods have been compared using FT-IR and X-ray diffraction techniques. Cellulose synthesized by Acetobacter xylinum NQ-5 strain from agitated culture conditions is characterized by a lower Ia mass fraction than cellulose that was produced statically. Such a decrease was in good(More)
Microbial cellulose (MC) synthesized in abundance by Acetobacter xylinum shows vast potential as a novel wound healing system. The high mechanical strength and remarkable physical properties result from the unique nanostructure of the never-dried membrane. This article attempts to briefly summarize the recent developments and applications of MC in the(More)
Schroedinger Eigenmaps (SE) has recently emerged as a powerful graph-based technique for semi-supervised manifold learning and recovery. By extending the Laplacian of a graph constructed from hyperspectral imagery to incorporate barrier or cluster potentials, SE enables machine learning techniques that employ expert/labeled information provided at a subset(More)
We introduce Schroedinger Eigenmaps (SE), a new semi-supervised manifold learning and recovery technique. This method is based on an implementation of graph Schroedinger operators with appropriately constructed barrier potentials as carriers of labeled information. We use our approach for the analysis of standard biomedical datasets and new multispectral(More)
The gene networks underlying closure of the optic fissure during vertebrate eye development are poorly understood. We used a novel clustering method based on Laplacian Eigenmaps, a nonlinear dimension reduction method, to analyze microarray data from laser capture microdissected (LCM) cells at the site and developmental stages (days 10.5 to 12.5) of optic(More)
We study wave packet systems WP(ψ,M); that is, countable collections of dilations, translations, and modulations of a single function ψ ∈ L2(R). The parameters of these unitary actions form a discrete subset M ⊂ R+ × R × R. We introduce analogues of the notion of Beurling density, adapted to the geometry of discrete subsets of R+ × R × R, and notions of(More)
We present an algorithm to solve the two-dimensional Fredholm integral of the first kind with tensor product structure from a limited number of measurements, with the goal of using this method to speed up nuclear magnetic resonance spectroscopy. This is done by incorporating compressive sensing–type arguments to fill in missing measurements, using a priori(More)
Potential applications of 2D relaxation spectrum NMR and MRI to characterize complex water dynamics (e.g., compartmental exchange) in biology and other disciplines have increased in recent years. However, the large amount of data and long MR acquisition times required for conventional 2D MR relaxometry limits its applicability for in vivo preclinical and(More)