Search results for "DOMAIN"
showing 10 items of 2485 documents
Chemically driven phase separation in black lipid membranes and its coupling to membrane functions
1992
Abstract We analysed the single-channel current fluctuations of gramicidin in bimolecular lipid membranes in order to demonstrate (i) the influence of protein binding to the lateral organisation of a mixed membrane, and (ii) how this couples to the function of the ionophore. Examples of phase separations induced by synthetic polyelectrolytes, as models for peripheral membrane proteins, and specific ligand-receptor interactions are presented and discussed in view of the important lateral order-function relationship in biomembranes.
Hydrolysis of Phosphotriesters: A Theoretical Analysis of the Enzymatic and Solution Mechanisms
2012
A theoretical study on the alkaline hydrolysis of paraoxon, one of the most popular organophosphorus pesticides, in aqueous solution and in the active site of Pseudomonas diminuta phosphotriesterase (PTE) is presented. Simulations by means of hybrid quantum mechanics/molecular mechanics (QM/MM) potentials show that the hydrolysis of paraoxon takes place through an A(N)D(N) or associative mechanism both in solution and in the active site of PTE. The results correctly reproduce the magnitude of the activation free energies and can be used to rationalize the observed kinetic isotope effects (KIEs) for the hydrolysis of paraoxon in both media. Enzymatic hydrolysis of O,O-diethyl p-chlorophenyl …
Specific recognition and formation of two- dimensional streptavidin domains in monolayers: applications to molecular devices
1989
Abstract By virtue of the high-affinity specific interaction between the vitamin, biotin, and the protein, streptavidin, monolayers of synthetic lipids with biotin headgroups can tightly bind streptavidin at the lipid-water interface. Through this specific recognition fluorescently-labelled streptavidin spontaneously organizes in the plane of the interface to form large protein domains, directly visible in situ by fluorescence microscopy and exhibiting optical anisotropy. Further structural characterization has shown that these domains are two-dimensional protein crystals. Correlation with the known three-dimensional crystal structure of streptavidin indicates that two of streptavidin's fou…
Interaction between biotin lipids and streptavidin in monolayers: formation of oriented two-dimensional protein domains induced by surface recognitio…
1989
Highly specific ligand-receptor interactions generally characterize surface recognition reactions. Such processes can be simulated by streptavidin-biotin-specific binding. Biotin lipids have thus been synthesized, and their interaction with streptavidin (or avidin) at the air-water interface was directly shown by measurement of surface pressure isotherms and fluorescence microscopy. These proteins interact with the biotin lipid monolayer via specific binding or nonspecific adsorption. Both phenomena were clearly distinguished by use of the inactivated form of streptavidin. The binding of fluorescein-labeled streptavidin to monolayers was also directly observed by fluorescence microscopy. Th…
On the definition of generic multi-layered ontologies for urban applications
2000
Cooperation of information systems is essential for providing decision support for urban management applications. This involves sharing data across collections of the heterogeneous information systems that are used to manage large urban infrastructures. The objective of this work is to define a spatial ontology to describe key features of urban applications, providing a foundation for semantic reconciliation among heterogeneous spatial information sources. We propose a multi-layered ontologies definition framework consisting of ontology layers which are composed of a generic functional structure and one or more domain ontologies. The functional structure embodies general ontological concept…
Theoretical and Experimental Model for the Analysis of a Cardan Cross
2015
The work presents the aproach of initial moddeling and calculus in order to prepare an finite element investigation of the cardan transmission joint. For this, it is necessary to develop a flexible informational system that would connect the constructive design of cardan transmissions to the technological design within a unitary structure. Due to the typodimensional diversity of cardan transmissions, the design and manufacturing of the various components for a certain application domain (medical aparature, dental and agricultural machines, lifting and transportation machines etc.) has been typified. In order to study the problems that occur in the practice of using cardan transmissions, the…
Preventing Overlaps in Agglomerative Hierarchical Conceptual Clustering
2020
Hierarchical Clustering is an unsupervised learning task, whi-ch seeks to build a set of clusters ordered by the inclusion relation. It is usually assumed that the result is a tree-like structure with no overlapping clusters, i.e., where clusters are either disjoint or nested. In Hierarchical Conceptual Clustering (HCC), each cluster is provided with a conceptual description which belongs to a predefined set called the pattern language. Depending on the application domain, the elements in the pattern language can be of different nature: logical formulas, graphs, tests on the attributes, etc. In this paper, we tackle the issue of overlapping concepts in the agglomerative approach of HCC. We …
Molecular evolution of the metazoan protein kinase C multigene family
1996
Protein kinases C (PKCs) comprise closely related Ser/Thr kinases, ubiquitously present in animal tissues ; they respond to second messengers, e.g., Ca2+ and/or diacylglycerol, to express their activities. Two PKCs have been sequenced from Geodia cydonium, a member of the lowest multicellular animals, the sponges (Porifera). One sponge G. cydonium PKC, GCPKC1, belongs to the ''novel'' (Ca2+-independent) PKC (nPKC) subfamily while the second one, GCPKC2, has the hall-marks of the ''conventional'' (Ca2+-dependent) PKC (cPKC) subfamily. The alignment of the Ser/Thr catalytic kinase domains, of the predicted aa sequences for these cDNAs with respective segments from previously reported sequence…
Knowledge Extraction from Healthcare Data Using User-Adaptable Keywords-Based Query Language
2020
Nowadays, the volume of the information gathered by any organization increases more and more rapidly. It is essential to be able to use this information efficiently for it to benefit the operation of the organization. There is no point of gathering the information if it is not converted into knowledge. The knowledge extraction process becomes the backbone of any successful organization. Moreover, the extraction of the knowledge must be quick and efficient, so that the newly-obtained knowledge can be put in use at once. The problem addressed in this paper is how to allow the domain expert to extract the knowledge from their information systems themselves without involving the third party in …
Domain Expert Platform for Goal-Oriented Dialog Collection
2021
Today, most dialogue systems are fully or partly built using neural network architectures. A crucial prerequisite for the creation of a goal-oriented neural network dialogue system is a dataset that represents typical dialogue scenarios and includes various semantic annotations, e.g. intents, slots and dialogue actions, that are necessary for training a particular neural network architecture. In this demonstration paper, we present an easy to use interface and its back-end which is oriented to domain experts for the collection of goal-oriented dialogue samples. The platform not only allows to collect or write sample dialogues in a structured way, but also provides a means for simple annotat…