It Is NL-complete to Decide Whether a Hairpin Completion of Regular Languages Is Regular

The hairpin completion is an operation on formal languages which is inspired by the hairpin formation in biochemistry. Hairpin formations occur naturally within DNA-computing. It has been known that the hairpin completion of a regular language is linear context-free, but not regular, in general. However, for some time it is was open whether the regularity of the hairpin completion of a regular language is is decidable. In 2009 this decidability problem has been solved positively by providing a polynomial time algorithm. In this paper we improve the complexity bound by showing that the decision problem is actually NL-complete. This complexity bound holds for both, the one-sided and the two-sided hairpin completions

Post buckling stress state of open section cylindrical shells subjected to constrained torsion

The work concerns numerical and experimental studies on pre and post buckling of thin-walled steel cylindrical shells of open section subjected to constrained torsion. Two structure solutions different in geometry are considered: open section cylindrical shell without stiffeners and reinforced by closed section stringers. The shells have five various length to diameter aspect ratio. Numerical simulations were carried out and the stress distribution in neuralgic zones in pre and post buckling response was determined. Torsion experiments were performed and the results were compared to the numerical solutions with a reasonably good agreement. The exactness of experiment for the chosen cases of considered solutions was proved by establishing the base for FEM numerical model estimation

An investigation into inter- and intragenomic variations of graphic genomic signatures

We provide, on an extensive dataset and using several different distances, confirmation of the hypothesis that CGR patterns are preserved along a genomic DNA sequence, and are different for DNA sequences originating from genomes of different species. This finding lends support to the theory that CGRs of genomic sequences can act as graphic genomic signatures. In particular, we compare the CGR patterns of over five hundred different 150,000 bp genomic sequences originating from the genomes of six organisms, each belonging to one of the kingdoms of life: H. sapiens, S. cerevisiae, A. thaliana, P. falciparum, E. coli, and P. furiosus. We also provide preliminary evidence of this method's applicability to closely related species by comparing H. sapiens (chromosome 21) sequences and over one hundred and fifty genomic sequences, also 150,000 bp long, from P. troglodytes (Animalia; chromosome Y), for a total length of more than 101 million basepairs analyzed. We compute pairwise distances between CGRs of these genomic sequences using six different distances, and construct Molecular Distance Maps that visualize all sequences as points in a two-dimensional or three-dimensional space, to simultaneously display their interrelationships. Our analysis confirms that CGR patterns of DNA sequences from the same genome are in general quantitatively similar, while being different for DNA sequences from genomes of different species. Our analysis of the performance of the assessed distances uses three different quality measures and suggests that several distances outperform the Euclidean distance, which has so far been almost exclusively used for such studies. In particular we show that, for this dataset, DSSIM (Structural Dissimilarity Index) and the descriptor distance (introduced here) are best able to classify genomic sequences.Comment: 14 pages, 6 figures, 5 table

Mechanical Force and Actin Dynamics during Cutaneous Squamous Cell Carcinoma (cSCC) Progression: Opportunities for Novel Treatment Modalities

Cutaneous squamous cell carcinoma (cSCC) accounts for 25% of cutaneous malignancies diagnosed in the Caucasian population. Surgical removal in combination with radio- and chemotherapy is an effective treatment; however, prognosis for patients suffering from aggressive cSCC is still relatively poor. Increasing prevalence coupled with high mortality and morbidity in aggressive metastatic forms of cSCC highlights the need for development of novel targeted therapeutics. Metastasis is a complex process requiring dramatic reorganization of the cell cytoskeleton. Recent studies have highlighted the importance of mechanical forces and actin dynamics in cancer cells’ intrinsic ability to invade adjacent tissues, intravasate into vasculature, and ultimately metastasize. Tight regulation of the biochemical and mechanical properties of the actin cytoskeleton drives cellular processes involved in cSCC progression including polarity establishment, morphogenesis, and motility. Here we will provide a short introduction to disease pathogenesis, give an overview of the role of key regulatory proteins governing the mechanical forces and actin dynamics critical to cSCC progression, and describe the contribution of actin remodeling and actomyosin signaling to cSCC progression. We will also discuss how targeting protein regulating mechanical force and actin dynamics may have clinical utility in development of novel treatment modalities for patients suffering from aggressive cSCC