9288911
The search for a new model structure of β-Factor XIIa
We present the search for a new model of β-factor XIIa, a blood coagulation enzyme, with an unknown experimental 3D-structure. We decided to build not one but three different models using different homologous proteins as well as different techniques and different modellers. Additional studies, including extensive molecular dynamics simulations on the solvated state, allowed us to draw several conclusions concerning homology modelling, in general, and β-factor XIIa, in particular.
4634224
Structural analysis of the KGD sequence loop of barbourin, an αIIbβ3-specific disintegrin
Disintegrins constitute a class of small proteins that inhibit platelet aggregation by binding to the fibrinogen receptor, also referred to as integrin αIIbβ3. Contrarily to other disintegrins that bind to a series of integrins via their Arg-Gly-Asp domain, the recognition site of barbourin contains a Lys-Gly-Asp sequence that ensures its specificity towards αIIbβ3. In this article, a three-dimensional model of barbourin is proposed using homology modeling and large-scale molecular dynamics simulations. The conformations of the Lys-Gly-Asp sequence of barbourin are analyzed and compared to those of peptidomimetics that exhibit similar specificity towards αIIbβ3. The tryptophan residue following the Lys-Gly-Asp sequence of the binding domain is shown to play a crucial role in the biological activity and the specificity of barbourin. Our results suggest that this disintegrin anchors to the binding pocket of the γ-chain of fibrinogen rather than to those of the Arg-Gly-Asp sequence.
207871495
Related Research on Implicit Ratings
A s the World Wide Web continues to grow, people find it impossible to access even a small portion of the information generated in a day from Usenet news, e-mail, and Web postings. Automated filters help us to prioritize and access only the information in which we’re interested. Because opinions differ about the importance or relevance of information, people need personalized filters. Adaptive filtering and recommendation systems are gaining significance as electronic commerce grows, and will likely extend into other information activities such as electronic library usage. Such systems must, however, “know” each user’s interest level in the material being viewed in order to build accurate profiles of the user or Web page, and to use those profiles for recommendation or filtering. The common solution, explicit ratings, involves users telling the system what they think about a piece of information. It is fairly well understood and accurate but interrupts normal browsing and reading patterns. To infer user interest, implicit ratings rely on a method that is less intrusive than direct user feedback. To collect, measure, and evaluate the predictive power of implicit interest indicators, we developed a Web browser to record user actions (implicit ratings) and explicit ratings for each page visited. We conducted a user study and studied correlations between various implicit indicators and explicit interest. We also examined how implicit interest indicators impact user privacy.
10827335
A novel approach for analyzing dynamics in neural networks with saturated characteristics
Current theories about the dynamics of neural networks with nonlinear characteristics and parameterized by set of parameters are mostly based on approximations in one way or another. In this paper we first introduce a rigorous approach which allows us to check in which parameter region a given saturated state is an attractor of the dynamics: a saturated state w=(wi, i=1,...,N)∈{-1,1}N is an attractor of the dynamics if and only if there is a local field gap between neurons in J+(w)={i, wi=1} and J-(w)={i, wi=−1}. Then we apply the result to analyze several models in neural networks. In particular in the Hopfield model we calculate the capacity and give an exact relation between the capacity and the threshold.
10774169
Significance of random neuronal drive
Abstract Effectively random firing occurs frequently in the brain. Random components of neuronal drive are therefore often major influences on activity. We describe here how level of drive, inhibitory/excitatory balance, correlation between input streams, EPSP/IPSP characteristics, the nature of the postsynaptic neuron all affect pattern and level of firing, the influence often interacting in complex ways. Random firing might also be instrumental in facilitating synchronized firing. These factors are possibly important elements of the mechanisms by which some neural networks encode information. Clarifying them might therefore facilitate a deeper understanding of the nature of the neural code.
22693835
The new economy: an engineer's perspective
From his twin perspectives as a career-long telecommunications engineer and Chairman of one of the UK's largest electronics companies, Sir David Brown will reflect on whether and when the New Economy, seemingly so long coming, will finally arrive. He will begin by exploring how the prospect of everything being digital; everyone having broadband; and intelligence being everywhere is changing our understanding of mobility. Then he will comment on the economic effects of that changed understanding under three headings - the macroeconomy, microeconomy and socioeconomy - before suggesting the criteria we might use to decide when the New Economy has arrived.
18397185
Motor Fault Diagnosis Based on Wavelet Energy and Immune Neural Network
Motor fault diagnosis methods are crucial in acquiring safe and reliable operation in motor drive systems. In this paper, a new method for the motor fault diagnosis is proposed based on wavelet packet transform (WPT) and artificial neural network (ANN). The energy of the vibration signals of motor can be obtained by the multi-decomposition of WPT and used as feature values of ANN inputs for fault diagnosis system. The artificial immune algorithm (AIA) for data clustering is employed to adaptively choose the centers and widths of the hidden layer centers of the radial basis function neural network (RBFNN). The simulation experiment results show the applicability and effectiveness of the proposed method to motor fault diagnosis.