The " knotting " properties of Brownian motion are investigated. Because the path of Brownian motion in 3-space intersects itself, the topological definition of a knot does not apply. A modified concept is defined; implication in a knot-tube. It is shown that 3-space Brownian motion is implicated in infinitely many disjoint knot-tubes in every time interval. As a corollary every segment of the ...

DNA topology changes dynamically during DNA replication. Supercoiling, precatenation, catenation and knotting interplay throughout the process that is finely regulated by DNA topoisomerases. In the present article, we provide an overview of theoretical and experimental approaches to understand the interplay between various manifestations of topological constraints acting on replicating DNA mole...

We show that for every m ∈ N , there exists an n ∈ N such that every embedding of the complete graph Kn in R contains a link of two components whose linking number is at least m . Furthermore, there exists an r ∈ N such that every embedding of Kr in R contains a knot Q with |a2(Q)| ≥ m , where a2(Q) denotes the second coefficient of the Conway polynomial of Q . AMS Classification 57M25; 05C10

R of the genetic code can be temporarily suspended to make room for a variety of specific tricks that direct synthesis of additional proteins from mRNAs that would not be predicted by their sequences. This ‘‘recoding’’ includes specification of the 21st encoded amino acid, selenocysteine (1, 2). In another form, recoding itself provides a sensing mechanism to regulate expression (3). In other c...

Urethral catheterization is a common procedure among pediatric patients. Intravesical knotting of a polyethylene feeding tube used as a urethral catheter is rare. This report described such a complication in an infant who had urethral catheterization with 5 Fr feeding tube. Removal of the catheter necessitated cystotomy. This complication is preventable if the feeding tube is inserted only as s...

15 2.2.6. Permanent sequence-driven bends 16 2.3. Stretching out the double helix 17 2.3.1. Small forces (< k B T /A = 0.08 pN) 18 2.3.2. Larger forces (> k B T /A = 0.08 pN) 18 2.3.3. Free energy of the semiflexible polymer 19 2.3.4. Really large forces (> 10 pN) 21 3. Strand Separation 22 3.1. Free-energy models of strand separation 23 3.1.1. Sequence-dependent models 24 3.1.2. Free energy of...

Stochastic simulations of coarse-grained protein models are used to investigate the propensity to form knots in early stages of protein folding. The study is carried out comparatively for two homologous carbamoyltransferases, a natively-knotted N-acetylornithine carbamoyltransferase (AOTCase) and an unknotted ornithine carbamoyltransferase (OTCase). In addition, two different sets of pairwise a...

1. Paediatric Epidural and Caudal Analgesia and Anaesthesia in Children. NYSORA; 2014. Available from: http://www. anes-som.ucsd.edu/Intranet/Peds_Resources/Regional/. [Last cited on 2015 Oct 24]. 2. Pinciroli R, Fumagalli R. The unexpected epidural: A case report. BMC Anesthesiol 2015;15:83. 3. Joselyn A, Bhalla T, Schloss B, Martin D, Tobias J. A case report of a retained and knotted caudal c...

Protein knots and slipknots, mostly regarded as intriguing oddities, are gradually being recognized as significant structural motifs. Recent experimental results show that knotting, starting from a fully extended polypeptide, has not yet been observed. Understanding the nucleation process of folding knots is thus a natural challenge for both experimental and theoretical investigation. In this s...