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Helicases use the energy derived from nucleoside triphosphate hydrolysis to unwind double helices in essentially every metabolic pathway involving nucleic acids. Earlier crystal structures have suggested that DNA helicases translocate along a single-stranded DNA in an inchworm fashion. We report here a series of crystal structures of the UvrD helicase(More)
Automatic skin detection has been intensively studied for human-related recognition systems. A Gaussian model for skin detection is a well-known approach with its simplicity and generality. In this paper, we discuss limitations of the Gaussian model and suggest a new statistical color model for skin detection, called an elliptical boundary model. The(More)
—An accurate model of IEEE 802.11e EDCA for a performance analysis that captures all major QoS features of the standard is introduced in this paper. Using the model, we derive the saturation throughput, and validate the accuracy of the proposed model through comparisons with other models via simulations. NOTATIONS See next page for the notations that are(More)
—An important quality-of-service (QoS) issue in wireless multimedia networks is how to control handoff drops. In this paper, we propose admission-control algorithms that adaptively control the admission threshold in each cell in order to keep the handoff-dropping probability below a predefined level. The admission threshold is dynamically adjusted based on(More)
Fig. 1 Influences of crystal lattice contacts on Pol η structures. a. The dominant lattice contact between two hPol η molecules (silver and gold) in the type 1 crystals. b. A close-up view of the hydrophobic interactions between W339 of one molecule and V372 and C406 of the other. These three residues and E335 were mutated as listed on the right to break(More)
— In spite of using IEEE 802.11 as medium access control (MAC), most of the ad-hoc routing protocols do not consider contention time that occurs in the medium reservation procedure. Large, contention times can be more critical than hop counts in determining the end-to-end delay. In ad-hoc networks, traffic concentration on some mobile nodes leads to long(More)
Tpa1 (for termination and polyadenylation) from Saccharomyces cerevisiae is a component of a messenger ribonucleoprotein (mRNP) complex at the 3' untranslated region of mRNAs. It comprises an N-terminal Fe(II)- and 2-oxoglutarate (2OG) dependent dioxygenase domain and a C-terminal domain. The N-terminal dioxygenase domain of a homologous Ofd1 protein from(More)
Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form(More)
Over the past decade, there has been substantial interest in the role of the integral myelin protein, Nogo-A, from fundamental neurobiological to clinical perspectives. It is now a well-known inhibitor of neurite outgrowth through its cognate receptor, Nogo receptor 1 (NgR1). Nogo-A can only signal through NgR1 upon heteromeric collaboration with p75(NTR),(More)