Approximate Counting of Graphical Realizations

In 1999 Kannan, Tetali and Vempala proposed a MCMC method to uniformly sample all possible realizations of a given graphical degree sequence and conjectured its rapidly mixing nature. Recently their conjecture was proved affirmative for regular graphs (by Cooper, Dyer and Greenhill, 2007), for regular directed graphs (by Greenhill, 2011) and for half-regular bipartite graphs (by Miklós, Erdős and Soukup, 2013). Several heuristics on counting the number of possible realizations exist (via sampling processes), and while they work well in practice, so far no approximation guarantees exist for such an approach. This paper is the first to develop a method for counting realizations with provable approximation guarantee. In fact, we solve a slightly more general problem; besides the graphical degree sequence a small set of forbidden edges is also given. We show that for the general problem (which contains the Greenhill problem and the Miklós, Erdős and Soukup problem as special cases) the derived MCMC process is rapidly mixing. Further, we show that this new problem is self-reducible therefore it provides a fully polynomial randomized approximation scheme (a.k.a. FPRAS) for counting of all realizations

On a parity based group testing algorithm

In traditional Combinatorial Group Testing the problem is to identify up to d defective items from a set of n items on the basis of group tests. In this paper we describe a variant of the group testing problem above, which we call parity group testing. The problem is to identify up to d defective items from a set of n items as in the classical group test problem. The main difference is that we check the parity of the defective items in a subset. The test can be applied to an arbitrary subset of the n items with two possible outcomes. The test is positive if the number of defective items in the subset is odd, otherwise it is negative. In this paper we extend Hirschberg et al.’s method to the parity group testing scenario

Sortilin Is Expressed in Cultured Human Keratinocytes and Is Regulated by Cutaneous Neuropeptides

Sortilin, a member of the family of Vps10p domain receptors, has been shown to be able to bind the precursor peptide of nerve growth factor (proNGF). ProNGF interacts with sortilin and the p75NTR receptor on the cell surface to form a molecular complex capable of activating an apoptotic cascade. Keratinocytes can secrete proNGF and they have p75NTR on their surface. The expression of sortilin in normal human keratinocytes has not yet been clearly shown. In this study, we show that keratinocytes express sortilin mRNA, and the presence of sortilin protein is shown in cultured keratinocytes and in normal human skin. We have also shown that the cutaneous neuropeptides substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and galanin are able to reduce the expression of sortilin mRNA and sortilin protein in cultured human keratinocytes. In addition, each of the analyzed neuropeptides has the ability to arrest the proNGF-induced apoptosis of human keratinocytes. These results suggest that all the participants in the NGF/proNGF pathway are present in the keratinocytes, and cutaneous neuropeptides can modulate their expressions and actions. The NGF/proNGF balance and its regulation by neuropeptides may have an important role in skin homeostasis

A biológiai kezelés során bekövetkező hatásvesztés gyakorisága, okai és klinikai megközelítése gyulladásos bélbetegségek esetén = Epidemiology, Predictors and Clinical Aspects of Loss of Response to Biological Therapy

In the last two decades, the treatment paradigms for Crohn’s disease and ulcerative colitis have significantly changed inclusive of a continuously increasing role of biological therapy (anti TNFs). Some patients, however, experience lack or loss of response to biological treatment, and in such cases the management of patients is often empirical. In this review, the authors aim to summarize the available data regarding epidemiology and predictors of loss of response to biological therapy considering the clinical factors and the relationship between serum concentrations, antibodies against biological agents, respectively. Monitoring drug levels and antibodies is expected to play an important role in the management of loss of response (i.e. to confirm adherence, allow dose adjustment, or provide rationale for switching to another biological agent or to a different class of biological agent) in the coming years. The optimal method of detection and cut-off values are, however, not clear. In clinical practice, meticulous complex assessment of clinical symptoms, confirmation of active disease by endoscopic or radiological imaging, and excluding complications remain necessary. Orv. Hetil., 2012, 153, 163–173. </jats:p