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Sample records for adaptive ligand recognition

  1. LIBRA: LIgand Binding site Recognition Application.

    Science.gov (United States)

    Hung, Le Viet; Caprari, Silvia; Bizai, Massimiliano; Toti, Daniele; Polticelli, Fabio

    2015-12-15

    In recent years, structural genomics and ab initio molecular modeling activities are leading to the availability of a large number of structural models of proteins whose biochemical function is not known. The aim of this study was the development of a novel software tool that, given a protein's structural model, predicts the presence and identity of active sites and/or ligand binding sites. The algorithm implemented by ligand binding site recognition application (LIBRA) is based on a graph theory approach to find the largest subset of similar residues between an input protein and a collection of known functional sites. The algorithm makes use of two predefined databases for active sites and ligand binding sites, respectively, derived from the Catalytic Site Atlas and the Protein Data Bank. Tests indicate that LIBRA is able to identify the correct binding/active site in 90% of the cases analyzed, 90% of which feature the identified site as ranking first. As far as ligand binding site recognition is concerned, LIBRA outperforms other structure-based ligand binding sites detection tools with which it has been compared. The application, developed in Java SE 7 with a Swing GUI embedding a JMol applet, can be run on any OS equipped with a suitable Java Virtual Machine (JVM), and is available at the following URL: http://www.computationalbiology.it/software/LIBRAv1.zip. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Selective ligand recognition by a diversity-generating retroelement variable protein.

    Directory of Open Access Journals (Sweden)

    Jason L Miller

    2008-06-01

    Full Text Available Diversity-generating retroelements (DGRs recognize novel ligands through massive protein sequence variation, a property shared uniquely with the adaptive immune response. Little is known about how recognition is achieved by DGR variable proteins. Here, we present the structure of the Bordetella bacteriophage DGR variable protein major tropism determinant (Mtd bound to the receptor pertactin, revealing remarkable adaptability in the static binding sites of Mtd. Despite large dissimilarities in ligand binding mode, principles underlying selective recognition were strikingly conserved between Mtd and immunoreceptors. Central to this was the differential amplification of binding strengths by avidity (i.e., multivalency, which not only relaxed the demand for optimal complementarity between Mtd and pertactin but also enhanced distinctions among binding events to provide selectivity. A quantitatively similar balance between complementarity and avidity was observed for Bordetella bacteriophage DGR as occurs in the immune system, suggesting that variable repertoires operate under a narrow set of conditions to recognize novel ligands.

  3. Quality based approach for adaptive face recognition

    Science.gov (United States)

    Abboud, Ali J.; Sellahewa, Harin; Jassim, Sabah A.

    2009-05-01

    Recent advances in biometric technology have pushed towards more robust and reliable systems. We aim to build systems that have low recognition errors and are less affected by variation in recording conditions. Recognition errors are often attributed to the usage of low quality biometric samples. Hence, there is a need to develop new intelligent techniques and strategies to automatically measure/quantify the quality of biometric image samples and if necessary restore image quality according to the need of the intended application. In this paper, we present no-reference image quality measures in the spatial domain that have impact on face recognition. The first is called symmetrical adaptive local quality index (SALQI) and the second is called middle halve (MH). Also, an adaptive strategy has been developed to select the best way to restore the image quality, called symmetrical adaptive histogram equalization (SAHE). The main benefits of using quality measures for adaptive strategy are: (1) avoidance of excessive unnecessary enhancement procedures that may cause undesired artifacts, and (2) reduced computational complexity which is essential for real time applications. We test the success of the proposed measures and adaptive approach for a wavelet-based face recognition system that uses the nearest neighborhood classifier. We shall demonstrate noticeable improvements in the performance of adaptive face recognition system over the corresponding non-adaptive scheme.

  4. Integration of screening and identifying ligand(s) from medicinal plant extracts based on target recognition by using NMR spectroscopy

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Yalin Tang, Qian Shang, Junfeng Xiang, Qianfan Yang, Qiuju Zhou, Lin Li, Hong Zhang, Qian Li, Hongxia Sun, Aijiao Guan, Wei Jiang & Wei Gai ### Abstract This protocol presents the screening of ligand(s) from medicinal plant extracts based on target recognition by using NMR spectroscopy. A detailed description of sample preparation and analysis process is provided. NMR spectroscopies described here are 1H NMR, diffusion-ordered spectroscopy (DOSY), relaxation-edited NMR, 1H–1...

  5. Structural determinants for selective recognition of peptide ligands for endothelin receptor subtypes ETA and ETB.

    Science.gov (United States)

    Lättig, Jens; Oksche, Alexander; Beyermann, Michael; Rosenthal, Walter; Krause, Gerd

    2009-07-01

    The molecular basis for recognition of peptide ligands endothelin-1, -2 and -3 in endothelin receptors is poorly understood. Especially the origin of ligand selectivity for ET(A) or ET(B) is not clearly resolved. We derived sequence-structure-function relationships of peptides and receptors from mutational data and homology modeling. Our major findings are the dissection of peptide ligands into four epitopes and the delineation of four complementary structural portions on receptor side explaining ligand recognition in both endothelin receptor subtypes. In addition, structural determinants for ligand selectivity could be described. As a result, we could improve the selectivity of BQ3020 about 10-fold by a single amino acid substitution, validating our hypothesis for ligand selectivity caused by different entrances to the receptors' transmembrane binding sites. A narrow tunnel shape in ET(A) is restrictive for a selected group of peptide ligands' N-termini, whereas a broad funnel-shaped entrance in ET(B) accepts a variety of different shapes and properties of ligands.

  6. Optical pattern recognition via adaptive spatial homodyne detection.

    Science.gov (United States)

    Hsu, Magnus T L; Knittel, Joachim; Morizur, Jean-Francois; Bachor, Hans-A; Bowen, Warwick P

    2010-12-01

    We present an experimental demonstration of an optical pattern recognition scheme based on spatial homodyne detection. Our scheme is adaptive, all-optical, utilizes a single-element photo-detector, and provides a single parameter readout to quantify the efficacy of pattern recognition, thereby allowing very fast pattern recognition speeds. The spatial homodyne detector was applied to the identification of one- and two-dimensional phase profiles.

  7. Mispronunciation Detection for Language Learning and Speech Recognition Adaptation

    Science.gov (United States)

    Ge, Zhenhao

    2013-01-01

    The areas of "mispronunciation detection" (or "accent detection" more specifically) within the speech recognition community are receiving increased attention now. Two application areas, namely language learning and speech recognition adaptation, are largely driving this research interest and are the focal points of this work.…

  8. ON­LINE CHARACTER RECOGNITION ADAPTIVELY CONTROLLED BY HANDWRITING QUALITY

    NARCIS (Netherlands)

    Hamanaka, M.; Yamada, K.

    2004-01-01

    On­line character recognition which can adapt to handwriting quality is proposed. In character recognition, it is difficult to recognize both clearly and roughly written characters accurately. For Japanese characters, the number of strokes is often slightly varied when characters are written

  9. Computational studies of protein-ligand molecular recognition

    NARCIS (Netherlands)

    Gillies, M.B.

    2001-01-01

    Structure-based drug design is made possible by our understanding of molecular recognition. The utility of this approach was apparent in the development of the clinically e V ective HIV-1 PR inhibitors, where crystal structures of complexes of HIV-1 protease and inhibitors gave pivotal information.

  10. Computational studies of protein-ligand molecular recognition

    OpenAIRE

    Gillies, M.B.

    2001-01-01

    Structure-based drug design is made possible by our understanding of molecular recognition. The utility of this approach was apparent in the development of the clinically e V ective HIV-1 PR inhibitors, where crystal structures of complexes of HIV-1 protease and inhibitors gave pivotal information. Computational methods drawing upon structural data are of increasing relevance to the drug design process. Nonetheless, these methods are quite rudimentary and signicant improvements are needed. Th...

  11. A Bifunctional Spin Label for Ligand Recognition on Surfaces

    OpenAIRE

    Hollas, Michael A.; Webb, Simon J.; Flitsch, Sabine L.; Fielding, Alistair J.

    2017-01-01

    Abstract In?situ monitoring of biomolecular recognition, especially at surfaces, still presents a significant technical challenge. Electron paramagnetic resonance (EPR) of biomolecules spin?labeled with nitroxides can offer uniquely sensitive and selective insights into these processes, but new spin?labeling strategies are needed. The synthesis and study of a bromoacrylaldehyde spin label (BASL), which features two attachment points with orthogonal reactivity is reported. The first examples o...

  12. Structural basis for ligand recognition of incretin receptors

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Parthier, Christoph; Reedtz-Runge, Steffen

    2010-01-01

    The glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor are homologous G-protein-coupled receptors (GPCRs). Incretin receptor agonists stimulate the synthesis and secretion of insulin from pancreatic β-cells and are therefore promising agents...... appear to be the main driving force for ligand binding to the ECD of incretin receptors. Obviously, the-still missing-structures of full-length incretin receptors are required to construct a complete picture of receptor function at the molecular level. However, the progress made recently in structural...

  13. Peptide ligand recognition by G protein-coupled receptors

    Directory of Open Access Journals (Sweden)

    Brian E Krumm

    2015-03-01

    Full Text Available The past few years have seen spectacular progress in the structure determination of G protein-coupled receptors (GPCRs. We now have structural representatives from classes A, B, C, and F. Within the rhodopsin-like class A, most structures belong to the α group, whereas fewer GPCR structures are available from the β, γ, and δ groups, which include peptide GPCRs such as the receptors for neurotensin (β group, opioids, chemokines (γ group, and protease-activated receptors (δ group. Structural information on peptide GPCRs is restricted to complexes with non-peptidic drug-like antagonists with the exception of the chemokine receptor CXCR4 that has been crystallized in the presence of a cyclic peptide antagonist. Notably, the neurotensin receptor (NTSR1 is to date the only peptide GPCR whose structure has been solved in the presence of a peptide agonist. Although limited in number, the current peptide GPCR structures reveal great diversity in shape and electrostatic properties of the ligand binding pockets, features that play key roles in the discrimination of ligands. Here, we review these aspects of peptide GPCRs in view of possible models for peptide agonist binding.

  14. Fuzzy support vector machines for adaptive Morse code recognition.

    Science.gov (United States)

    Yang, Cheng-Hong; Jin, Li-Cheng; Chuang, Li-Yeh

    2006-11-01

    Morse code is now being harnessed for use in rehabilitation applications of augmentative-alternative communication and assistive technology, facilitating mobility, environmental control and adapted worksite access. In this paper, Morse code is selected as a communication adaptive device for persons who suffer from muscle atrophy, cerebral palsy or other severe handicaps. A stable typing rate is strictly required for Morse code to be effective as a communication tool. Therefore, an adaptive automatic recognition method with a high recognition rate is needed. The proposed system uses both fuzzy support vector machines and the variable-degree variable-step-size least-mean-square algorithm to achieve these objectives. We apply fuzzy memberships to each point, and provide different contributions to the decision learning function for support vector machines. Statistical analyses demonstrated that the proposed method elicited a higher recognition rate than other algorithms in the literature.

  15. Heterogeneity and dynamics of the ligand recognition mode in purine-sensing riboswitches.

    Science.gov (United States)

    Jain, Niyati; Zhao, Liang; Liu, John D; Xia, Tianbing

    2010-05-04

    High-resolution crystal structures and biophysical analyses of purine-sensing riboswitches have revealed that a network of hydrogen bonding interactions appear to be largey responsible for discrimination of cognate ligands against structurally related compounds. Here we report that by using femtosecond time-resolved fluorescence spectroscopy to capture the ultrafast decay dynamics of the 2-aminopurine base as the ligand, we have detected the presence of multiple conformations of the ligand within the binding pockets of one guanine-sensing and two adenine-sensing riboswitches. All three riboswitches have similar conformational distributions of the ligand-bound state. The known crystal structures represent the global minimum that accounts for 50-60% of the population, where there is no significant stacking interaction between the ligand and bases of the binding pocket, but the hydrogen-bonding cage collectively provides an electronic environment that promotes an ultrafast ( approximately 1 ps) charge transfer pathway. The ligand also samples multiple conformations in which it significantly stacks with either the adenine or the uracil bases of the A21-U75 and A52-U22 base pairs that form the ceiling and floor of the binding pocket, respectively, but favors the larger adenine bases. These alternative conformations with well-defined base stacking interactions are approximately 1-1.5 kcal/mol higher in DeltaG degrees than the global minimum and have distinct charge transfer dynamics within the picosecond to nanosecond time regime. Inside the pocket, the purine ligand undergoes dynamic motion on the low nanosecond time scale, sampling the multiple conformations based on time-resolved anisotropy decay dynamics. These results allowed a description of the energy landscape of the bound ligand with intricate details and demonstrated the elastic nature of the ligand recognition mode by the purine-sensing riboswitches, where there is a dynamic balance between hydrogen bonding

  16. Histogram Equalization to Model Adaptation for Robust Speech Recognition

    Directory of Open Access Journals (Sweden)

    Suh Youngjoo

    2010-01-01

    Full Text Available We propose a new model adaptation method based on the histogram equalization technique for providing robustness in noisy environments. The trained acoustic mean models of a speech recognizer are adapted into environmentally matched conditions by using the histogram equalization algorithm on a single utterance basis. For more robust speech recognition in the heavily noisy conditions, trained acoustic covariance models are efficiently adapted by the signal-to-noise ratio-dependent linear interpolation between trained covariance models and utterance-level sample covariance models. Speech recognition experiments on both the digit-based Aurora2 task and the large vocabulary-based task showed that the proposed model adaptation approach provides significant performance improvements compared to the baseline speech recognizer trained on the clean speech data.

  17. Histogram Equalization to Model Adaptation for Robust Speech Recognition

    Science.gov (United States)

    Suh, Youngjoo; Kim, Hoirin

    2010-12-01

    We propose a new model adaptation method based on the histogram equalization technique for providing robustness in noisy environments. The trained acoustic mean models of a speech recognizer are adapted into environmentally matched conditions by using the histogram equalization algorithm on a single utterance basis. For more robust speech recognition in the heavily noisy conditions, trained acoustic covariance models are efficiently adapted by the signal-to-noise ratio-dependent linear interpolation between trained covariance models and utterance-level sample covariance models. Speech recognition experiments on both the digit-based Aurora2 task and the large vocabulary-based task showed that the proposed model adaptation approach provides significant performance improvements compared to the baseline speech recognizer trained on the clean speech data.

  18. Speaker adaptation in the NIST Speaker Recognition Evaluation 2004

    NARCIS (Netherlands)

    Leeuwen, D.A. van

    2005-01-01

    New in the 2004 edition of the NIST Speaker Recognition Evaluation (SRE) was the condition where unsupervised adaptation of speaker models is allowed. Despite the promising results on development test material, hardly any beneficial results were obtained in the Evaluation itself. An analysis is made

  19. ADAPTIVE CONTEXT PROCESSING IN ON-LINE HANDWRITTEN CHARACTER RECOGNITION

    NARCIS (Netherlands)

    Iwayama, N.; Ishigaki, K.

    2004-01-01

    We propose a new approach to context processing in on-line handwritten character recognition (OLCR). Based on the observation that writers often repeat the strings that they input, we take the approach of adaptive context processing. (ACP). In ACP, the strings input by a writer are automatically

  20. Mechanistic pathways of recognition of a solvent-inaccessible cavity of protein by a ligand

    Science.gov (United States)

    Mondal, Jagannath; Pandit, Subhendu; Dandekar, Bhupendra; Vallurupalli, Pramodh

    One of the puzzling questions in the realm of protein-ligand recognition is how a solvent-inaccessible hydrophobic cavity of a protein gets recognized by a ligand. We address the topic by simulating, for the first time, the complete binding process of benzene from aqueous media to the well-known buried cavity of L99A T4 Lysozyme at an atomistic resolution. Our multiple unbiased microsecond-long trajectories, which were completely blind to the location of target binding site, are able to unequivocally identify the kinetic pathways along which benzene molecule meanders across the solvent and protein and ultimately spontaneously recognizes the deeply buried cavity of L99A T4 Lysozyme at an accurate precision. Our simulation, combined with analysis based on markov state model and free energy calculation, reveals that there are more than one distinct ligand binding pathways. Intriguingly, each of the identified pathways involves the transient opening of a channel of the protein prior to ligand binding. The work will also decipher rich mechanistic details on unbinding kinetics of the ligand as obtained from enhanced sampling techniques.

  1. Roles for ordered and bulk solvent in ligand recognition and docking in two related cavities.

    Directory of Open Access Journals (Sweden)

    Sarah Barelier

    Full Text Available A key challenge in structure-based discovery is accounting for modulation of protein-ligand interactions by ordered and bulk solvent. To investigate this, we compared ligand binding to a buried cavity in Cytochrome c Peroxidase (CcP, where affinity is dominated by a single ionic interaction, versus a cavity variant partly opened to solvent by loop deletion. This opening had unexpected effects on ligand orientation, affinity, and ordered water structure. Some ligands lost over ten-fold in affinity and reoriented in the cavity, while others retained their geometries, formed new interactions with water networks, and improved affinity. To test our ability to discover new ligands against this opened site prospectively, a 534,000 fragment library was docked against the open cavity using two models of ligand solvation. Using an older solvation model that prioritized many neutral molecules, three such uncharged docking hits were tested, none of which was observed to bind; these molecules were not highly ranked by the new, context-dependent solvation score. Using this new method, another 15 highly-ranked molecules were tested for binding. In contrast to the previous result, 14 of these bound detectably, with affinities ranging from 8 µM to 2 mM. In crystal structures, four of these new ligands superposed well with the docking predictions but two did not, reflecting unanticipated interactions with newly ordered waters molecules. Comparing recognition between this open cavity and its buried analog begins to isolate the roles of ordered solvent in a system that lends itself readily to prospective testing and that may be broadly useful to the community.

  2. Video Shot Boundary Recognition Based on Adaptive Locality Preserving Projections

    Directory of Open Access Journals (Sweden)

    Yongliang Xiao

    2013-01-01

    Full Text Available A novel video shot boundary recognition method is proposed, which includes two stages of video feature extraction and shot boundary recognition. Firstly, we use adaptive locality preserving projections (ALPP to extract video feature. Unlike locality preserving projections, we define the discriminating similarity with mode prior probabilities and adaptive neighborhood selection strategy which make ALPP more suitable to preserve the local structure and label information of the original data. Secondly, we use an optimized multiple kernel support vector machine to classify video frames into boundary and nonboundary frames, in which the weights of different types of kernels are optimized with an ant colony optimization method. Experimental results show the effectiveness of our method.

  3. Adaptive Morse code recognition using variable degree variable step size LMS for persons with disabilities.

    Science.gov (United States)

    Yang, C H

    1998-01-01

    In this paper, we applied variable degree, variable step size LMS algorithm to adaptive Morse code recognition for persons with impaired hand coordination and dexterity. The automatic recognition of Morse code by the disabled is difficult because they cannot maintain a stable typing rate. Therefore, a suitable adaptive automatic recognition method is needed. In this adaptive Morse code recognition method, three processes are involved: character separation, character recognition, and adaptive processing. Statistical analyses demonstrated that the proposed method resulted in a better recognition rate compared to alternative methods from the literature.

  4. A Folded Excited State of Ligand-Free Nuclear Coactivator Binding Domain (NCBD) Underlies Plasticity in Ligand Recognition

    DEFF Research Database (Denmark)

    Kjaergaard, Magnus; Andersen, Lisbeth; Nielsen, Lau Dalby

    2013-01-01

    Intrinsically disordered proteins are renowned for their structural plasticity when they undergo coupled folding and binding to partner proteins. The nuclear coactivator binding domain of CBP is a remarkable example of this adaptability as it folds into two different conformations depending...... experience conformational exchange. The dispersion data can be described by a global two-state exchange process between a ground state and an excited state populated to 8%. The three helices are still folded in the excited state but have a different packing from the ground state; the contact between helices...... with that of NCBD in complex with the ligand IRF-3. The energy landscape of this domain is thus proposed to resemble the fold-switching proteins that have two coexisting native states, which may serve as a starting point for binding via conformational selection....

  5. An Adaptive Classification Strategy for Reliable Locomotion Mode Recognition

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2017-09-01

    Full Text Available Algorithms for locomotion mode recognition (LMR based on surface electromyography and mechanical sensors have recently been developed and could be used for the neural control of powered prosthetic legs. However, the variations in input signals, caused by physical changes at the sensor interface and human physiological changes, may threaten the reliability of these algorithms. This study aimed to investigate the effectiveness of applying adaptive pattern classifiers for LMR. Three adaptive classifiers, i.e., entropy-based adaptation (EBA, LearnIng From Testing data (LIFT, and Transductive Support Vector Machine (TSVM, were compared and offline evaluated using data collected from two able-bodied subjects and one transfemoral amputee. The offline analysis indicated that the adaptive classifier could effectively maintain or restore the performance of the LMR algorithm when gradual signal variations occurred. EBA and LIFT were recommended because of their better performance and higher computational efficiency. Finally, the EBA was implemented for real-time human-in-the-loop prosthesis control. The online evaluation showed that the applied EBA effectively adapted to changes in input signals across sessions and yielded more reliable prosthesis control over time, compared with the LMR without adaptation. The developed novel adaptive strategy may further enhance the reliability of neurally-controlled prosthetic legs.

  6. Road Sign Recognition with Fuzzy Adaptive Pre-Processing Models

    Directory of Open Access Journals (Sweden)

    Ming-Shi Wang

    2012-05-01

    Full Text Available A road sign recognition system based on adaptive image pre-processing models using two fuzzy inference schemes has been proposed. The first fuzzy inference scheme is to check the changes of the light illumination and rich red color of a frame image by the checking areas. The other is to check the variance of vehicle’s speed and angle of steering wheel to select an adaptive size and position of the detection area. The Adaboost classifier was employed to detect the road sign candidates from an image and the support vector machine technique was employed to recognize the content of the road sign candidates. The prohibitory and warning road traffic signs are the processing targets in this research. The detection rate in the detection phase is 97.42%. In the recognition phase, the recognition rate is 93.04%. The total accuracy rate of the system is 92.47%. For video sequences, the best accuracy rate is 90.54%, and the average accuracy rate is 80.17%. The average computing time is 51.86 milliseconds per frame. The proposed system can not only overcome low illumination and rich red color around the road sign problems but also offer high detection rates and high computing performance.

  7. Folding and ligand recognition of the TPP riboswitch aptamer at single-molecule resolution.

    Science.gov (United States)

    Haller, Andrea; Altman, Roger B; Soulière, Marie F; Blanchard, Scott C; Micura, Ronald

    2013-03-12

    Thiamine pyrophosphate (TPP)-sensitive mRNA domains are the most prevalent riboswitches known. Despite intensive investigation, the complex ligand recognition and concomitant folding processes in the TPP riboswitch that culminate in the regulation of gene expression remain elusive. Here, we used single-molecule fluorescence resonance energy transfer imaging to probe the folding landscape of the TPP aptamer domain in the absence and presence of magnesium and TPP. To do so, distinct labeling patterns were used to sense the dynamics of the switch helix (P1) and the two sensor arms (P2/P3 and P4/P5) of the aptamer domain. The latter structural elements make interdomain tertiary contacts (L5/P3) that span a region immediately adjacent to the ligand-binding site. In each instance, conformational dynamics of the TPP riboswitch were influenced by ligand binding. The P1 switch helix, formed by the 5' and 3' ends of the aptamer domain, adopts a predominantly folded structure in the presence of Mg(2+) alone. However, even at saturating concentrations of Mg(2+) and TPP, the P1 helix, as well as distal regions surrounding the TPP-binding site, exhibit an unexpected degree of residual dynamics and disperse kinetic behaviors. Such plasticity results in a persistent exchange of the P3/P5 forearms between open and closed configurations that is likely to facilitate entry and exit of the TPP ligand. Correspondingly, we posit that such features of the TPP aptamer domain contribute directly to the mechanism of riboswitch-mediated translational regulation.

  8. Adaptive Deep Supervised Autoencoder Based Image Reconstruction for Face Recognition

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    Rongbing Huang

    2016-01-01

    Full Text Available Based on a special type of denoising autoencoder (DAE and image reconstruction, we present a novel supervised deep learning framework for face recognition (FR. Unlike existing deep autoencoder which is unsupervised face recognition method, the proposed method takes class label information from training samples into account in the deep learning procedure and can automatically discover the underlying nonlinear manifold structures. Specifically, we define an Adaptive Deep Supervised Network Template (ADSNT with the supervised autoencoder which is trained to extract characteristic features from corrupted/clean facial images and reconstruct the corresponding similar facial images. The reconstruction is realized by a so-called “bottleneck” neural network that learns to map face images into a low-dimensional vector and reconstruct the respective corresponding face images from the mapping vectors. Having trained the ADSNT, a new face image can then be recognized by comparing its reconstruction image with individual gallery images, respectively. Extensive experiments on three databases including AR, PubFig, and Extended Yale B demonstrate that the proposed method can significantly improve the accuracy of face recognition under enormous illumination, pose change, and a fraction of occlusion.

  9. HMM Adaptation for Improving a Human Activity Recognition System

    Directory of Open Access Journals (Sweden)

    Rubén San-Segundo

    2016-09-01

    Full Text Available When developing a fully automatic system for evaluating motor activities performed by a person, it is necessary to segment and recognize the different activities in order to focus the analysis. This process must be carried out by a Human Activity Recognition (HAR system. This paper proposes a user adaptation technique for improving a HAR system based on Hidden Markov Models (HMMs. This system segments and recognizes six different physical activities (walking, walking upstairs, walking downstairs, sitting, standing and lying down using inertial signals from a smartphone. The system is composed of a feature extractor for obtaining the most relevant characteristics from the inertial signals, a module for training the six HMMs (one per activity, and the last module for segmenting new activity sequences using these models. The user adaptation technique consists of a Maximum A Posteriori (MAP approach that adapts the activity HMMs to the user, using some activity examples from this specific user. The main results on a public dataset have reported a significant relative error rate reduction of more than 30%. In conclusion, adapting a HAR system to the user who is performing the physical activities provides significant improvement in the system’s performance.

  10. Innate immune recognition of double-stranded RNA triggers increased expression of NKG2D ligands after virus infection.

    Science.gov (United States)

    Esteso, Gloria; Guerra, Susana; Valés-Gómez, Mar; Reyburn, Hugh T

    2017-12-15

    Self/non-self-discrimination by the innate immune system relies on germline-encoded, non-rearranging receptors expressed by innate immune cells recognizing conserved pathogen-associated molecular patterns. The natural killer group 2D (NKG2D) receptor is a potent immune-activating receptor that binds human genome-encoded ligands, whose expression is negligible in normal tissues, but increased in stress and disease conditions for reasons that are incompletely understood. Here it is not clear how the immune system reconciles receptor binding of self-proteins with self/non-self-discrimination to avoid autoreactivity. We now report that increased expression of NKG2D ligands after virus infection depends on interferon response factors activated by the detection of viral double-stranded RNA by pattern-recognition receptors (RIG-I/MDA-5) and that NKG2D ligand up-regulation can be blocked by the expression of viral dsRNA-binding proteins. Thus, innate immunity-mediated recognition of viral nucleic acids triggers the infected cell to release interferon for NK cell recruitment and to express NKG2D ligands to become more visible to the immune system. Finally, the observation that NKG2D-ligand induction is a consequence of signaling by pattern-recognition receptors that have been selected over evolutionary time to be highly pathogen-specific explains how the risks of autoreactivity in this system are minimized. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Unique contributions of an arginine side chain to ligand recognition in a glutamate-gated chloride channel

    DEFF Research Database (Denmark)

    Lynagh, Timothy; Komnatnyy, Vitaly V; Pless, Stephan A

    2017-01-01

    Glutamate recognition by neurotransmitter receptors often relies on arginine (Arg) residues in the binding site, leading to the assumption that charge-charge interactions underlie ligand recognition. However, assessing the precise chemical contribution of Arg side chains to protein function...... and pharmacology has proven to be exceedingly difficult in such large and complex proteins. Using the in vivo nonsense suppression approach, we report the first successful incorporation of the isosteric, titratable Arg analog, canavanine, into a neurotransmitter receptor in a living cell, utilizing a glutamate......-gated chloride channel from the nematode Haemonchus contortus. Our data unveil a surprisingly small contribution of charge at a conserved arginine side chain previously suggested to form a salt bridge with the ligand, glutamate. Instead, our data show that Arg contributes crucially to ligand sensitivity via...

  12. Ligand binding and signaling of dendritic cell immunoreceptor (DCIR is modulated by the glycosylation of the carbohydrate recognition domain.

    Directory of Open Access Journals (Sweden)

    Karien Bloem

    Full Text Available C-type lectins are innate receptors expressed on antigen-presenting cells that are involved in the recognition of glycosylated pathogens and self-glycoproteins. Upon ligand binding, internalization and/or signaling often occur. Little is known on the glycan specificity and ligands of the Dendritic Cell Immunoreceptor (DCIR, the only classical C-type lectin that contains an intracellular immunoreceptor tyrosine-based inhibitory motif (ITIM. Here we show that purified DCIR binds the glycan structures Lewis(b and Man3. Interestingly, binding could not be detected when DCIR was expressed on cells. Since DCIR has an N-glycosylation site inside its carbohydrate recognition domain (CRD, we investigated the effect of this glycan in ligand recognition. Removing or truncating the glycans present on purified DCIR increased the affinity for DCIR-binding glycans. Nevertheless, altering the glycosylation status of the DCIR expressing cell or mutating the N-glycosylation site of DCIR itself did not increase glycan binding. In contrast, cis and trans interactions with glycans induced DCIR mediated signaling, resulting in a decreased phosphorylation of the ITIM sequence. These results show that glycan binding to DCIR is influenced by the glycosylation of the CRD region in DCIR and that interaction with its ligands result in signaling via its ITIM motif.

  13. Structural Basis for Ligand Recognition and Discrimination of a Quorum-quenching Antibody

    Energy Technology Data Exchange (ETDEWEB)

    Kirchdoerfer, Robert N.; Garner, Amanda L.; Flack, Caralyn E.; Mee, Jenny M.; Horswill, Alexander R.; Janda, Kim D.; Kaufmann, Gunnar F.; Wilson, Ian A. (Scripps); (Iowa)

    2011-09-16

    In the postantibiotic era, available treatment options for severe bacterial infections caused by methicillin-resistant Staphylococcus aureus have become limited. Therefore, new and innovative approaches are needed to combat such life-threatening infections. Virulence factor expression in S. aureus is regulated in a cell density-dependent manner using 'quorum sensing,' which involves generation and secretion of autoinducing peptides (AIPs) into the surrounding environment to activate a bacterial sensor kinase at a particular threshold concentration. Mouse monoclonal antibody AP4-24H11 was shown previously to blunt quorum sensing-mediated changes in gene expression in vitro and protect mice from a lethal dose of S. aureus by sequestering the AIP signal. We have elucidated the crystal structure of the AP4-24H11 Fab in complex with AIP-4 at 2.5 {angstrom} resolution to determine its mechanism of ligand recognition. A key GluH95 provides much of the binding specificity through formation of hydrogen bonds with each of the four amide nitrogens in the AIP-4 macrocyclic ring. Importantly, these structural data give clues as to the interactions between the cognate staphylococcal AIP receptors AgrC and the AIPs, as AP4-24H11 {center_dot} AIP-4 binding recapitulates features that have been proposed for AgrC-AIP recognition. Additionally, these structural insights may enable the engineering of AIP cross-reactive antibodies or quorum quenching vaccines for use in active or passive immunotherapy for prevention or treatment of S. aureus infections.

  14. Incipient speciation of sea star populations by adaptive gamete recognition coevolution.

    Science.gov (United States)

    Hart, Michael W; Sunday, Jennifer M; Popovic, Iva; Learning, Kevin J; Konrad, Christine M

    2014-05-01

    Reproductive isolation--the key event in speciation--can evolve when sexual conflict causes selection favoring different combinations of male and female adaptations in different populations. Likely targets of such selection include genes that encode proteins on the surfaces of sperm and eggs, but no previous study has demonstrated intraspecific coevolution of interacting gamete recognition genes under selection. Here, we show that selection drives coevolution between an egg receptor for sperm (OBi1) and a sperm acrosomal protein (bindin) in diverging populations of a sea star (Patiria miniata). We found positive selection on OBi1 in an exon encoding part of its predicted substrate-binding protein domain, the ligand for which is found in bindin. Gene flow was zero for the parts of bindin and OBi1 in which selection for high rates of amino acid substitution was detected; higher gene flow for other parts of the genome indicated selection against immigrant alleles at bindin and OBi1. Populations differed in allele frequencies at two key positively selected sites (one in each gene), and differences at those sites predicted fertilization rate variation among male-female pairs. These patterns suggest adaptively evolving loci that influence reproductive isolation between populations. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  15. Structural Insights into Ligand Recognition by a Sensing Domain of the Cooperative Glycine Riboswitch

    Energy Technology Data Exchange (ETDEWEB)

    L Huang; A Serganov; D Patel

    2011-12-31

    Glycine riboswitches regulate gene expression by feedback modulation in response to cooperative binding to glycine. Here, we report on crystal structures of the second glycine-sensing domain from the Vibrio cholerae riboswitch in the ligand-bound and unbound states. This domain adopts a three-helical fold that centers on a three-way junction and accommodates glycine within a bulge-containing binding pocket above the junction. Glycine recognition is facilitated by a pair of bound Mg{sup 2+} cations and governed by specific interactions and shape complementarity with the pocket. A conserved adenine extrudes from the binding pocket and intercalates into the junction implying that glycine binding in the context of the complete riboswitch could impact on gene expression by stabilizing the riboswitch junction and regulatory P1 helix. Analysis of riboswitch interactions in the crystal and footprinting experiments indicates that adjacent glycine-sensing modules of the riboswitch could form specific interdomain interactions, thereby potentially contributing to the cooperative response.

  16. Adapted all-numerical correlator for face recognition applications

    Science.gov (United States)

    Elbouz, M.; Bouzidi, F.; Alfalou, A.; Brosseau, C.; Leonard, I.; Benkelfat, B.-E.

    2013-03-01

    In this study, we suggest and validate an all-numerical implementation of a VanderLugt correlator which is optimized for face recognition applications. The main goal of this implementation is to take advantage of the benefits (detection, localization, and identification of a target object within a scene) of correlation methods and exploit the reconfigurability of numerical approaches. This technique requires a numerical implementation of the optical Fourier transform. We pay special attention to adapt the correlation filter to this numerical implementation. One main goal of this work is to reduce the size of the filter in order to decrease the memory space required for real time applications. To fulfil this requirement, we code the reference images with 8 bits and study the effect of this coding on the performances of several composite filters (phase-only filter, binary phase-only filter). The saturation effect has for effect to decrease the performances of the correlator for making a decision when filters contain up to nine references. Further, an optimization is proposed based for an optimized segmented composite filter. Based on this approach, we present tests with different faces demonstrating that the above mentioned saturation effect is significantly reduced while minimizing the size of the learning data base.

  17. Speaker-Adaptation for Hybrid HMM-ANN Continuous Speech Recognition System

    OpenAIRE

    Neto, Joao; Almeida, Luis; Hochberg, Mike; Martins, Ciro; Nunes, Luis; Renals, Steve; Robinson, Tony

    1995-01-01

    It is well known that recognition performance degrades significantly when moving from a speaker-dependent to a speaker-independent system. Traditional hidden Markov model (HMM) systems have successfully applied speaker-adaptation approaches to reduce this degradation. In this paper we present and evaluate some techniques for speaker-adaptation of a hybrid HMM-artificial neural network (ANN) continuous speech recognition system. These techniques are applied to a well trained, speaker-independe...

  18. A strategy using NMR peptide structures of thromboxane A2 receptor as templates to construct ligand-recognition pocket of prostacyclin receptor

    Directory of Open Access Journals (Sweden)

    Ruan Ke-He

    2005-11-01

    Full Text Available Abstract Background: Prostacyclin receptor (IP and thromboxane A2 receptor (TP belong to rhodopsin-type G protein-coupling receptors and respectively bind to prostacyclin and thromboxane A2 derived from arachidonic acid. Recently, we have determined the extracellular loop (eLP structures of the human TP receptor by 2-D 1H NMR spectroscopy using constrained peptides mimicking the individual eLP segments. The studies have identified the segment along with several residues in the eLP domains important to ligand recognition, as well as proposed a ligand recognition pocket for the TP receptor. Results: The IP receptor shares a similar primary structure in the eLPs with those of the TP receptor. Forty percent residues in the second eLPs of the receptors are identical, which is the major region involved in forming the ligand recognition pocket in the TP receptor. Based on the high homology score, the eLP domains of the IP receptor were constructed by the homology modeling approach using the NMR structures of the TP eLPs as templates, and then configured to the seven transmembrane (TM domains model constructed using the crystal structure of the bovine rhodopsin as a template. A NMR structure of iloprost was docked into the modeled IP ligand recognition pocket. After dynamic studies, the segments and residues involved in the IP ligand recognition were proposed. A key residue, Arg173 involved in the ligand recognition for the IP receptor, as predicted from the modeling, was confirmed by site-directed mutagenesis. Conclusion: A 3-D model of the human IP receptor was constructed by homology modeling using the crystal structure of bovine rhodopsin TM domains and the NMR structures of the synthetic constrained peptides of the eLP domains of the TP receptor as templates. This strategy can be applied to molecular modeling and the prediction of ligand recognition pockets for other prostanoid receptors.

  19. DMBT1 functions as pattern-recognition molecule for poly-sulfated and poly-phosphorylated ligands

    DEFF Research Database (Denmark)

    End, Caroline; Bikker, Floris; Renner, Marcus

    2009-01-01

    Deleted in malignant brain tumors 1 (DMBT1) is a secreted glycoprotein displaying a broad bacterial-binding spectrum. Recent functional and genetic studies linked DMBT1 to the suppression of LPS-induced TLR4-mediated NF-kappaB activation and to the pathogenesis of Crohn's disease. Here, we aimed ...... that DMBT1 functions as pattern-recognition molecule for poly-sulfated and poly-phosphorylated ligands providing a molecular basis for its broad bacterial-binding specificity and its inhibitory effects on LPS-induced TLR4-mediated NF-kappaB activation....

  20. Contributions of Phenylalanine 335 to Ligand Recognition by Human Surfactant Protein D: Ring Interactions with SP-D Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Crouch,E.; McDonald, B.; Smith, K.; Cararella, T.; Seaton, B.; Head, J.

    2006-01-01

    Surfactant Protein D (SP-D) is an innate immune effector that contributes to antimicrobial host defense and immune regulation. Interactions of SP-D with microorganisms and organic antigens involve binding of glycoconjugates to the C-type lectin carbohydrate recognition domain (CRD). A trimeric fusion protein encoding the human neck+CRD (hNCRD) bound to the aromatic glycoside, p-nitrophenyl-alpha-D-maltoside, with nearly a log-fold higher affinity than maltose, the prototypical competitor. Maltotriose, which has the same linkage pattern as the maltoside, bound with intermediate affinity. Site-directed substitution of leucine for phenylalanine 335 (Phe335) decreased affinities for the maltoside and maltotriose without significantly altering the affinity for maltose or glucose, and substitution of tyrosine or tryptophan for leucine restored preferential binding to maltotriose and the maltoside. A mutant with alanine at this position failed to bind to mannan or maltose-substituted solid supports. Crystallographic analysis of the hNCRD complexed with maltotriose or p-nitrophenyl-maltoside showed stacking of the terminal glucose or nitrophenyl ring with the aromatic ring of Phe335. Our studies indicate that Phe335, which is evolutionarily conserved in all known SP-Ds, plays important - if not critical roles - in SP-D function.

  1. Molecular basis for convergent evolution of glutamate recognition by pentameric ligand-gated ion channels

    DEFF Research Database (Denmark)

    Lynagh, Timothy; Beech, Robin N.; Lalande, Maryline J.

    2015-01-01

    that glutamate recognition requires an arginine residue in the base of the binding site, which originated at least three distinct times according to phylogenetic analysis. Most remarkably, the arginine emerged on the principal face of the binding site in the Lophotrochozoan lineage, but 65 amino acids upstream......Glutamate is an indispensable neurotransmitter, triggering postsynaptic signals upon recognition by postsynaptic receptors. We questioned the phylogenetic position and the molecular details of when and where glutamate recognition arose in the glutamate-gated chloride channels. Experiments revealed......, on the complementary face, in the Ecdysozoan lineage. This combined experimental and computational approach throws new light on the evolution of synaptic signalling....

  2. Allograph Based Writer Adaptation for Handwritten Character Recognition

    OpenAIRE

    Chellapilla, Kumar; Simard, Patrice; Abdulkader, Ahmad

    2006-01-01

    http://www.suvisoft.com; Writer adaptation is the process of converting a generic (writer-independent) handwriting recognizer into a personalized (writer-dependent) recognizer with improved accuracy for a particular user. While training the generic recognizer uses large amounts of data from several writers, the adaptation process uses only a few samples from a single user. In this paper we present a) an automatic approach for identifying allographs (character shapes/styles) from handwritten c...

  3. Recognition of voice commands using adaptation of foreign language speech recognizer via selection of phonetic transcriptions

    Science.gov (United States)

    Maskeliunas, Rytis; Rudzionis, Vytautas

    2011-06-01

    In recent years various commercial speech recognizers have become available. These recognizers provide the possibility to develop applications incorporating various speech recognition techniques easily and quickly. All of these commercial recognizers are typically targeted to widely spoken languages having large market potential; however, it may be possible to adapt available commercial recognizers for use in environments where less widely spoken languages are used. Since most commercial recognition engines are closed systems the single avenue for the adaptation is to try set ways for the selection of proper phonetic transcription methods between the two languages. This paper deals with the methods to find the phonetic transcriptions for Lithuanian voice commands to be recognized using English speech engines. The experimental evaluation showed that it is possible to find phonetic transcriptions that will enable the recognition of Lithuanian voice commands with recognition accuracy of over 90%.

  4. Action adaptation during natural unfolding social scenes influences action recognition and inferences made about actor beliefs.

    Science.gov (United States)

    Keefe, Bruce D; Wincenciak, Joanna; Jellema, Tjeerd; Ward, James W; Barraclough, Nick E

    2016-07-01

    When observing another individual's actions, we can both recognize their actions and infer their beliefs concerning the physical and social environment. The extent to which visual adaptation influences action recognition and conceptually later stages of processing involved in deriving the belief state of the actor remains unknown. To explore this we used virtual reality (life-size photorealistic actors presented in stereoscopic three dimensions) to see how visual adaptation influences the perception of individuals in naturally unfolding social scenes at increasingly higher levels of action understanding. We presented scenes in which one actor picked up boxes (of varying number and weight), after which a second actor picked up a single box. Adaptation to the first actor's behavior systematically changed perception of the second actor. Aftereffects increased with the duration of the first actor's behavior, declined exponentially over time, and were independent of view direction. Inferences about the second actor's expectation of box weight were also distorted by adaptation to the first actor. Distortions in action recognition and actor expectations did not, however, extend across different actions, indicating that adaptation is not acting at an action-independent abstract level but rather at an action-dependent level. We conclude that although adaptation influences more complex inferences about belief states of individuals, this is likely to be a result of adaptation at an earlier action recognition stage rather than adaptation operating at a higher, more abstract level in mentalizing or simulation systems.

  5. Illumination robust face recognition using spatial adaptive shadow compensation based on face intensity prior

    Science.gov (United States)

    Hsieh, Cheng-Ta; Huang, Kae-Horng; Lee, Chang-Hsing; Han, Chin-Chuan; Fan, Kuo-Chin

    2017-12-01

    Robust face recognition under illumination variations is an important and challenging task in a face recognition system, particularly for face recognition in the wild. In this paper, a face image preprocessing approach, called spatial adaptive shadow compensation (SASC), is proposed to eliminate shadows in the face image due to different lighting directions. First, spatial adaptive histogram equalization (SAHE), which uses face intensity prior model, is proposed to enhance the contrast of each local face region without generating visible noises in smooth face areas. Adaptive shadow compensation (ASC), which performs shadow compensation in each local image block, is then used to produce a wellcompensated face image appropriate for face feature extraction and recognition. Finally, null-space linear discriminant analysis (NLDA) is employed to extract discriminant features from SASC compensated images. Experiments performed on the Yale B, Yale B extended, and CMU PIE face databases have shown that the proposed SASC always yields the best face recognition accuracy. That is, SASC is more robust to face recognition under illumination variations than other shadow compensation approaches.

  6. Entropy-enthalpy compensation: Role and ramifications in biomolecular ligand recognition and design

    Science.gov (United States)

    Chodera, John D.; Mobley, David L.

    2014-01-01

    Recent calorimetric studies of small molecule interactions with biomolecular targets have generated renewed interest in the phenomenon of entropy-enthalpy compensation. In these studies, entropic and enthalpic contributions to binding are observed to vary substantially and in an opposing manner as the ligand or protein is modified while the binding free energy varies little. In severe examples, engineered enthalpic gains can lead to completely compensating entropic penalties, frustrating ligand design. Here, we examine the evidence for compensation, as well as its potential origins, prevalence, severity, and ramifications for ligand engineering. We find the evidence for severe compensation to be weak in light of the large magnitude of and correlation between errors in experimental measurements of entropic and enthalpic contributions to binding, though a limited form of compensation may be common. Given the difficulty of predicting or measuring entropic and enthalpic changes to useful precision, or using this information in design, we recommend ligand engineering efforts instead focus on computational and experimental methodologies to directly assess changes in binding free energy. PMID:23654303

  7. Cooperation between lateral ligand mobility and accessibility for receptor recognition in selectin-induced cell rolling

    NARCIS (Netherlands)

    Bakowsky, U; Schumacher, G; Gege, C; Schmidt, RR; Rothe, U; Bendas, G

    2002-01-01

    Selectin-induced leukocyte rolling along the endothelial surface is an essential step in the immune response. Several in vitro studies showed that this cell rolling is a highly regulated adhesion phenomenon, controlled by the kinetics and forces of selectin-ligand interactions. In the flow chamber

  8. AN ILLUMINATION INVARIANT FACE RECOGNITION BY ENHANCED CONTRAST LIMITED ADAPTIVE HISTOGRAM EQUALIZATION

    Directory of Open Access Journals (Sweden)

    A. Thamizharasi

    2016-05-01

    Full Text Available Face recognition system is gaining more importance in social networks and surveillance. The face recognition task is complex due to the variations in illumination, expression, occlusion, aging and pose. The illumination variations in image are due to changes in lighting conditions, poor illumination, low contrast or increased brightness. The variations in illumination adversely affect the quality of image and recognition accuracy. The illumination variations in face image have to be pre-processed prior to face recognition. The Contrast Limited Adaptive Histogram Equalization (CLAHE is an image enhancement technique popular in enhancing medical images. The proposed work is to create illumination invariant face recognition system by enhancing Contrast Limited Adaptive Histogram Equalization technique. This method is termed as “Enhanced CLAHE”. The efficiency of Enhanced CLAHE is tested using Fuzzy K Nearest Neighbour classifier and fisher face subspace projection method. The face recognition accuracy percentage rate, Equal Error Rate and False Acceptance Rate at 1% are calculated. The performance of CLAHE and Enhanced CLAHE methods is compared. The efficiency of the Enhanced CLAHE method is tested with three public face databases AR, Yale and ORL. The Enhanced CLAHE has very high recognition accuracy percentage rate when compared to CLAHE.

  9. A Novel Unsupervised Adaptive Learning Method for Long-Term Electromyography (EMG Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Qi Huang

    2017-06-01

    Full Text Available Performance degradation will be caused by a variety of interfering factors for pattern recognition-based myoelectric control methods in the long term. This paper proposes an adaptive learning method with low computational cost to mitigate the effect in unsupervised adaptive learning scenarios. We presents a particle adaptive classifier (PAC, by constructing a particle adaptive learning strategy and universal incremental least square support vector classifier (LS-SVC. We compared PAC performance with incremental support vector classifier (ISVC and non-adapting SVC (NSVC in a long-term pattern recognition task in both unsupervised and supervised adaptive learning scenarios. Retraining time cost and recognition accuracy were compared by validating the classification performance on both simulated and realistic long-term EMG data. The classification results of realistic long-term EMG data showed that the PAC significantly decreased the performance degradation in unsupervised adaptive learning scenarios compared with NSVC (9.03% ± 2.23%, p < 0.05 and ISVC (13.38% ± 2.62%, p = 0.001, and reduced the retraining time cost compared with ISVC (2 ms per updating cycle vs. 50 ms per updating cycle.

  10. A Novel Unsupervised Adaptive Learning Method for Long-Term Electromyography (EMG) Pattern Recognition.

    Science.gov (United States)

    Huang, Qi; Yang, Dapeng; Jiang, Li; Zhang, Huajie; Liu, Hong; Kotani, Kiyoshi

    2017-06-13

    Performance degradation will be caused by a variety of interfering factors for pattern recognition-based myoelectric control methods in the long term. This paper proposes an adaptive learning method with low computational cost to mitigate the effect in unsupervised adaptive learning scenarios. We presents a particle adaptive classifier (PAC), by constructing a particle adaptive learning strategy and universal incremental least square support vector classifier (LS-SVC). We compared PAC performance with incremental support vector classifier (ISVC) and non-adapting SVC (NSVC) in a long-term pattern recognition task in both unsupervised and supervised adaptive learning scenarios. Retraining time cost and recognition accuracy were compared by validating the classification performance on both simulated and realistic long-term EMG data. The classification results of realistic long-term EMG data showed that the PAC significantly decreased the performance degradation in unsupervised adaptive learning scenarios compared with NSVC (9.03% ± 2.23%, p < 0.05) and ISVC (13.38% ± 2.62%, p = 0.001), and reduced the retraining time cost compared with ISVC (2 ms per updating cycle vs. 50 ms per updating cycle).

  11. Molecular mechanism of ligand recognition by NR3 subtype glutamate receptors

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yongneng; Harrison, Chris B.; Freddolino, Peter L.; Schulten, Klaus; Mayer, Mark L. (UIUC); (NIH)

    2008-10-27

    NR3 subtype glutamate receptors have a unique developmental expression profile, but are the least well-characterized members of the NMDA receptor gene family, which have key roles in synaptic plasticity and brain development. Using ligand binding assays, crystallographic analysis, and all atom MD simulations, we investigate mechanisms underlying the binding by NR3A and NR3B of glycine and D-serine, which are candidate neurotransmitters for NMDA receptors containing NR3 subunits. The ligand binding domains of both NR3 subunits adopt a similar extent of domain closure as found in the corresponding NR1 complexes, but have a unique loop 1 structure distinct from that in all other glutamate receptor ion channels. Within their ligand binding pockets, NR3A and NR3B have strikingly different hydrogen bonding networks and solvent structures from those found in NR1, and fail to undergo a conformational rearrangement observed in NR1 upon binding the partial agonist ACPC. MD simulations revealed numerous interdomain contacts, which stabilize the agonist-bound closed-cleft conformation, and a novel twisting motion for the loop 1 helix that is unique in NR3 subunits.

  12. GAUSSIAN MIXTURE MODELS FOR ADAPTATION OF DEEP NEURAL NETWORK ACOUSTIC MODELS IN AUTOMATIC SPEECH RECOGNITION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Natalia A. Tomashenko

    2016-11-01

    Full Text Available Subject of Research. We study speaker adaptation of deep neural network (DNN acoustic models in automatic speech recognition systems. The aim of speaker adaptation techniques is to improve the accuracy of the speech recognition system for a particular speaker. Method. A novel method for training and adaptation of deep neural network acoustic models has been developed. It is based on using an auxiliary GMM (Gaussian Mixture Models model and GMMD (GMM-derived features. The principle advantage of the proposed GMMD features is the possibility of performing the adaptation of a DNN through the adaptation of the auxiliary GMM. In the proposed approach any methods for the adaptation of the auxiliary GMM can be used, hence, it provides a universal method for transferring adaptation algorithms developed for GMMs to DNN adaptation.Main Results. The effectiveness of the proposed approach was shown by means of one of the most common adaptation algorithms for GMM models – MAP (Maximum A Posteriori adaptation. Different ways of integration of the proposed approach into state-of-the-art DNN architecture have been proposed and explored. Analysis of choosing the type of the auxiliary GMM model is given. Experimental results on the TED-LIUM corpus demonstrate that, in an unsupervised adaptation mode, the proposed adaptation technique can provide, approximately, a 11–18% relative word error reduction (WER on different adaptation sets, compared to the speaker-independent DNN system built on conventional features, and a 3–6% relative WER reduction compared to the SAT-DNN trained on fMLLR adapted features.

  13. Molecular recognition in a diverse set of protein-ligand interactions studied with molecular dynamics simulations and end-point free energy calculations.

    Science.gov (United States)

    Wang, Bo; Li, Liwei; Hurley, Thomas D; Meroueh, Samy O

    2013-10-28

    End-point free energy calculations using MM-GBSA and MM-PBSA provide a detailed understanding of molecular recognition in protein-ligand interactions. The binding free energy can be used to rank-order protein-ligand structures in virtual screening for compound or target identification. Here, we carry out free energy calculations for a diverse set of 11 proteins bound to 14 small molecules using extensive explicit-solvent MD simulations. The structure of these complexes was previously solved by crystallography and their binding studied with isothermal titration calorimetry (ITC) data enabling direct comparison to the MM-GBSA and MM-PBSA calculations. Four MM-GBSA and three MM-PBSA calculations reproduced the ITC free energy within 1 kcal·mol(-1) highlighting the challenges in reproducing the absolute free energy from end-point free energy calculations. MM-GBSA exhibited better rank-ordering with a Spearman ρ of 0.68 compared to 0.40 for MM-PBSA with dielectric constant (ε = 1). An increase in ε resulted in significantly better rank-ordering for MM-PBSA (ρ = 0.91 for ε = 10), but larger ε significantly reduced the contributions of electrostatics, suggesting that the improvement is due to the nonpolar and entropy components, rather than a better representation of the electrostatics. The SVRKB scoring function applied to MD snapshots resulted in excellent rank-ordering (ρ = 0.81). Calculations of the configurational entropy using normal-mode analysis led to free energies that correlated significantly better to the ITC free energy than the MD-based quasi-harmonic approach, but the computed entropies showed no correlation with the ITC entropy. When the adaptation energy is taken into consideration by running separate simulations for complex, apo, and ligand (MM-PBSAADAPT), there is less agreement with the ITC data for the individual free energies, but remarkably good rank-ordering is observed (ρ = 0.89). Interestingly, filtering MD snapshots by prescoring

  14. Multisensor integration and image recognition using Fuzzy Adaptive Resonance Theory

    Science.gov (United States)

    Singer, Steven M.

    1997-04-01

    The main objective of this work was to investigate the use of 'sensor based real time decision and control technology' applied to actively control the arrestment of aircraft (manned or unmanned). The proposed method is to develop an adaptively controlled system that would locate the aircraft's extended tailhook, predict its position and speed at the time of arrestment, adjust an arresting end effector to actively mate with the arresting hook and remove the aircraft's kinetic energy, thus minimizing the arresting distance and impact stresses. The focus of the work presented in this paper was to explore the use of fuzzy adaptive resonance theorem (fuzzy art) neural network to form a MSI scheme which reduces image data to recognize incoming aircraft and extended tailhook. Using inputs from several image sources a single fused image was generated to give details about range and tailhook characteristics for an F18 naval aircraft. The idea is to partition an image into cells and evaluate each using fuzzy art. Once the incoming aircraft is located in a cell that subimage is again divided into smaller cells. This image is evaluated to locate various parts of the aircraft (i.e., wings, tail, tailhook, etc.). the cell that contains the tailhook provides resolved position information. Multiple images from separate sensors provides opportunity to generate range details overtime.

  15. Adaptive Self-Occlusion Behavior Recognition Based on pLSA

    Directory of Open Access Journals (Sweden)

    Hong-bin Tu

    2013-01-01

    Full Text Available Human action recognition is an important area of human action recognition research. Focusing on the problem of self-occlusion in the field of human action recognition, a new adaptive occlusion state behavior recognition approach was presented based on Markov random field and probabilistic Latent Semantic Analysis (pLSA. Firstly, the Markov random field was used to represent the occlusion relationship between human body parts in terms an occlusion state variable by phase space obtained. Then, we proposed a hierarchical area variety model. Finally, we use the topic model of pLSA to recognize the human behavior. Experiments were performed on the KTH, Weizmann, and Humaneva dataset to test and evaluate the proposed method. The compared experiment results showed that what the proposed method can achieve was more effective than the compared methods.

  16. FPGA IMPLEMENTATION OF ADAPTIVE INTEGRATED SPIKING NEURAL NETWORK FOR EFFICIENT IMAGE RECOGNITION SYSTEM

    Directory of Open Access Journals (Sweden)

    T. Pasupathi

    2014-05-01

    Full Text Available Image recognition is a technology which can be used in various applications such as medical image recognition systems, security, defense video tracking, and factory automation. In this paper we present a novel pipelined architecture of an adaptive integrated Artificial Neural Network for image recognition. In our proposed work we have combined the feature of spiking neuron concept with ANN to achieve the efficient architecture for image recognition. The set of training images are trained by ANN and target output has been identified. Real time videos are captured and then converted into frames for testing purpose and the image were recognized. The machine can operate at up to 40 frames/sec using images acquired from the camera. The system has been implemented on XC3S400 SPARTAN-3 Field Programmable Gate Arrays.

  17. Molecular recognition of carboxylates in the protein leucine zipper by a multivalent supramolecular ligand: residue-specific, sensitive and label-free probing by UV resonance Raman spectroscopy.

    Science.gov (United States)

    Zakeri, B; Niebling, S; Martinéz, A G; Sokkar, P; Sanchez-Garcia, E; Schmuck, C; Schlücker, S

    2018-01-17

    Ultraviolet resonance Raman (UVRR) spectroscopy is a selective, sensitive and label-free vibrational spectroscopic technique. Here, we demonstrate as proof of concept that UVRR can be used for probing the recognition between a multivalent supramolecular ligand and acidic residues in leucine zipper, an α-helical structural motif of many proteins.

  18. Prediction of Speech Recognition in Cochlear Implant Users by Adapting Auditory Models to Psychophysical Data

    Directory of Open Access Journals (Sweden)

    Svante Stadler

    2009-01-01

    Full Text Available Users of cochlear implants (CIs vary widely in their ability to recognize speech in noisy conditions. There are many factors that may influence their performance. We have investigated to what degree it can be explained by the users' ability to discriminate spectral shapes. A speech recognition task has been simulated using both a simple and a complex models of CI hearing. The models were individualized by adapting their parameters to fit the results of a spectral discrimination test. The predicted speech recognition performance was compared to experimental results, and they were significantly correlated. The presented framework may be used to simulate the effects of changing the CI encoding strategy.

  19. Enhancing Perception with Tactile Object Recognition in Adaptive Grippers for Human-Robot Interaction.

    Science.gov (United States)

    Gandarias, Juan M; Gómez-de-Gabriel, Jesús M; García-Cerezo, Alfonso J

    2018-02-26

    The use of tactile perception can help first response robotic teams in disaster scenarios, where visibility conditions are often reduced due to the presence of dust, mud, or smoke, distinguishing human limbs from other objects with similar shapes. Here, the integration of the tactile sensor in adaptive grippers is evaluated, measuring the performance of an object recognition task based on deep convolutional neural networks (DCNNs) using a flexible sensor mounted in adaptive grippers. A total of 15 classes with 50 tactile images each were trained, including human body parts and common environment objects, in semi-rigid and flexible adaptive grippers based on the fin ray effect. The classifier was compared against the rigid configuration and a support vector machine classifier (SVM). Finally, a two-level output network has been proposed to provide both object-type recognition and human/non-human classification. Sensors in adaptive grippers have a higher number of non-null tactels (up to 37% more), with a lower mean of pressure values (up to 72% less) than when using a rigid sensor, with a softer grip, which is needed in physical human-robot interaction (pHRI). A semi-rigid implementation with 95.13% object recognition rate was chosen, even though the human/non-human classification had better results (98.78%) with a rigid sensor.

  20. Automatic Query Generation and Query Relevance Measurement for Unsupervised Language Model Adaptation of Speech Recognition

    Directory of Open Access Journals (Sweden)

    Suzuki Motoyuki

    2009-01-01

    Full Text Available Abstract We are developing a method of Web-based unsupervised language model adaptation for recognition of spoken documents. The proposed method chooses keywords from the preliminary recognition result and retrieves Web documents using the chosen keywords. A problem is that the selected keywords tend to contain misrecognized words. The proposed method introduces two new ideas for avoiding the effects of keywords derived from misrecognized words. The first idea is to compose multiple queries from selected keyword candidates so that the misrecognized words and correct words do not fall into one query. The second idea is that the number of Web documents downloaded for each query is determined according to the "query relevance." Combining these two ideas, we can alleviate bad effect of misrecognized keywords by decreasing the number of downloaded Web documents from queries that contain misrecognized keywords. Finally, we examine a method of determining the number of iterative adaptations based on the recognition likelihood. Experiments have shown that the proposed stopping criterion can determine almost the optimum number of iterations. In the final experiment, the word accuracy without adaptation (55.29% was improved to 60.38%, which was 1.13 point better than the result of the conventional unsupervised adaptation method (59.25%.

  1. Automatic Query Generation and Query Relevance Measurement for Unsupervised Language Model Adaptation of Speech Recognition

    Directory of Open Access Journals (Sweden)

    Akinori Ito

    2009-01-01

    Full Text Available We are developing a method of Web-based unsupervised language model adaptation for recognition of spoken documents. The proposed method chooses keywords from the preliminary recognition result and retrieves Web documents using the chosen keywords. A problem is that the selected keywords tend to contain misrecognized words. The proposed method introduces two new ideas for avoiding the effects of keywords derived from misrecognized words. The first idea is to compose multiple queries from selected keyword candidates so that the misrecognized words and correct words do not fall into one query. The second idea is that the number of Web documents downloaded for each query is determined according to the “query relevance.” Combining these two ideas, we can alleviate bad effect of misrecognized keywords by decreasing the number of downloaded Web documents from queries that contain misrecognized keywords. Finally, we examine a method of determining the number of iterative adaptations based on the recognition likelihood. Experiments have shown that the proposed stopping criterion can determine almost the optimum number of iterations. In the final experiment, the word accuracy without adaptation (55.29% was improved to 60.38%, which was 1.13 point better than the result of the conventional unsupervised adaptation method (59.25%.

  2. Action recognition and movement direction discrimination tasks are associated with different adaptation patterns

    Directory of Open Access Journals (Sweden)

    Stephan eDe La Rosa

    2016-02-01

    Full Text Available The ability to discriminate between different actions is essential for action recognition and social interaction. Surprisingly previous research has often probed action recognition mechanisms with tasks that did not require participants to discriminate between actions, e.g. left-right direction discrimination tasks. It is not known to what degree visual processes in direction discrimination tasks are also involved in the discrimination of actions, e.g. when telling apart a handshake from a high-five. Here, we examined whether action discrimination is influenced by movement direction and whether direction discrimination depends on the type of action. We used an action adaptation paradigm to target action and direction discrimination specific visual processes. In separate conditions participants visually adapted to forward and backward moving handshake and high-five actions. Participants subsequently either categorized the action or the movement direction of an ambiguous action. The results showed that direction discrimination adaptation effects were modulated by the type of action but action discrimination adaptation effects were unaffected by movement direction. These results suggest that action discrimination and direction categorization rely on partly different visual information. We propose that action discrimination tasks should be considered for the exploration of visual action recognition mechanisms.

  3. Action Recognition and Movement Direction Discrimination Tasks Are Associated with Different Adaptation Patterns.

    Science.gov (United States)

    de la Rosa, Stephan; Ekramnia, Mina; Bülthoff, Heinrich H

    2016-01-01

    The ability to discriminate between different actions is essential for action recognition and social interactions. Surprisingly previous research has often probed action recognition mechanisms with tasks that did not require participants to discriminate between actions, e.g., left-right direction discrimination tasks. It is not known to what degree visual processes in direction discrimination tasks are also involved in the discrimination of actions, e.g., when telling apart a handshake from a high-five. Here, we examined whether action discrimination is influenced by movement direction and whether direction discrimination depends on the type of action. We used an action adaptation paradigm to target action and direction discrimination specific visual processes. In separate conditions participants visually adapted to forward and backward moving handshake and high-five actions. Participants subsequently categorized either the action or the movement direction of an ambiguous action. The results showed that direction discrimination adaptation effects were modulated by the type of action but action discrimination adaptation effects were unaffected by movement direction. These results suggest that action discrimination and direction categorization rely on partly different visual information. We propose that action discrimination tasks should be considered for the exploration of visual action recognition mechanisms.

  4. Enhancing Perception with Tactile Object Recognition in Adaptive Grippers for Human–Robot Interaction

    Directory of Open Access Journals (Sweden)

    Juan M. Gandarias

    2018-02-01

    Full Text Available The use of tactile perception can help first response robotic teams in disaster scenarios, where visibility conditions are often reduced due to the presence of dust, mud, or smoke, distinguishing human limbs from other objects with similar shapes. Here, the integration of the tactile sensor in adaptive grippers is evaluated, measuring the performance of an object recognition task based on deep convolutional neural networks (DCNNs using a flexible sensor mounted in adaptive grippers. A total of 15 classes with 50 tactile images each were trained, including human body parts and common environment objects, in semi-rigid and flexible adaptive grippers based on the fin ray effect. The classifier was compared against the rigid configuration and a support vector machine classifier (SVM. Finally, a two-level output network has been proposed to provide both object-type recognition and human/non-human classification. Sensors in adaptive grippers have a higher number of non-null tactels (up to 37% more, with a lower mean of pressure values (up to 72% less than when using a rigid sensor, with a softer grip, which is needed in physical human–robot interaction (pHRI. A semi-rigid implementation with 95.13% object recognition rate was chosen, even though the human/non-human classification had better results (98.78% with a rigid sensor.

  5. A Hybrid Acoustic and Pronunciation Model Adaptation Approach for Non-native Speech Recognition

    Science.gov (United States)

    Oh, Yoo Rhee; Kim, Hong Kook

    In this paper, we propose a hybrid model adaptation approach in which pronunciation and acoustic models are adapted by incorporating the pronunciation and acoustic variabilities of non-native speech in order to improve the performance of non-native automatic speech recognition (ASR). Specifically, the proposed hybrid model adaptation can be performed at either the state-tying or triphone-modeling level, depending at which acoustic model adaptation is performed. In both methods, we first analyze the pronunciation variant rules of non-native speakers and then classify each rule as either a pronunciation variant or an acoustic variant. The state-tying level hybrid method then adapts pronunciation models and acoustic models by accommodating the pronunciation variants in the pronunciation dictionary and by clustering the states of triphone acoustic models using the acoustic variants, respectively. On the other hand, the triphone-modeling level hybrid method initially adapts pronunciation models in the same way as in the state-tying level hybrid method; however, for the acoustic model adaptation, the triphone acoustic models are then re-estimated based on the adapted pronunciation models and the states of the re-estimated triphone acoustic models are clustered using the acoustic variants. From the Korean-spoken English speech recognition experiments, it is shown that ASR systems employing the state-tying and triphone-modeling level adaptation methods can relatively reduce the average word error rates (WERs) by 17.1% and 22.1% for non-native speech, respectively, when compared to a baseline ASR system.

  6. Low-resolution expression recognition based on central oblique average CS-LBP with adaptive threshold

    Science.gov (United States)

    Han, Sheng; Xi, Shi-qiong; Geng, Wei-dong

    2017-11-01

    In order to solve the problem of low recognition rate of traditional feature extraction operators under low-resolution images, a novel algorithm of expression recognition is proposed, named central oblique average center-symmetric local binary pattern (CS-LBP) with adaptive threshold (ATCS-LBP). Firstly, the features of face images can be extracted by the proposed operator after pretreatment. Secondly, the obtained feature image is divided into blocks. Thirdly, the histogram of each block is computed independently and all histograms can be connected serially to create a final feature vector. Finally, expression classification is achieved by using support vector machine (SVM) classifier. Experimental results on Japanese female facial expression (JAFFE) database show that the proposed algorithm can achieve a recognition rate of 81.9% when the resolution is as low as 16×16, which is much better than that of the traditional feature extraction operators.

  7. Enantioselective recognition of an isomeric ligand by a biomolecule: mechanistic insights into static and dynamic enantiomeric behavior and structural flexibility.

    Science.gov (United States)

    Peng, Wei; Ding, Fei

    2017-10-24

    Chirality is a ubiquitous basic attribute of nature, which inseparably relates to the life activity of living organisms. However, enantiomeric differences have still failed to arouse enough attention during the biological evaluation and practical application of chiral substances, and this poses a large threat to human health. In the current study, we explore the enantioselective biorecognition of a chiral compound by an asymmetric biomolecule, and then decipher the molecular basis of such a biological phenomenon on the static and, in particular, the dynamic scale. In light of the wet experiments, in silico docking results revealed that the orientation of the latter part of the optical isomer structures in the recognition domain can be greatly affected by the chiral carbon center in a model ligand molecule, and this event may induce large disparities between the static chiral bioreaction modes and noncovalent interactions (especially hydrogen bonding). Dynamic stereoselective biorecognition assays indicated that the conformational stability of the protein-(S)-diclofop system is clearly greater than the protein-(R)-diclofop adduct; and moreover, the conformational alterations of the diclofop enantiomers in the dynamic process will directly influence the conformational flexibility of the key residues found in the biorecognition region. These points enable the changing trends of biopolymer structural flexibility and free energy to exhibit significant distinctions when proteins sterically recognize the (R)-/(S)-stereoisomers. The outcomes of the energy decomposition further showed that the van der Waals' energy has roughly the same contribution to the chiral recognition biosystems, whereas the contribution of electrostatic energy to the protein-(R)-diclofop complex is notably smaller than to the protein-(S)-diclofop bioconjugate. This proves that differences in the noncovalent bonds would have a serious impact on the stereoselective biorecognition between a

  8. The recognition signal hypothesis for the adaptive evolution of religion : a phylogenetic test with Christian denominations.

    Science.gov (United States)

    Matthews, Luke J

    2012-06-01

    Recent research on the evolution of religion has focused on whether religion is an unselected by-product of evolutionary processes or if it is instead an adaptation by natural selection. Adaptive hypotheses for religion include direct fitness benefits from improved health and indirect fitness benefits mediated by costly signals and/or cultural group selection. Herein, I propose that religious denominations achieve indirect fitness gains for members through the use of ecologically arbitrary beliefs, rituals, and moral rules that function as recognition markers of cultural inheritance analogous to kin and species recognition of genetic inheritance in biology. This recognition signal hypotheses could act in concert with either costly signaling or cultural group selection to produce evolutionarily altruistic behaviors within denominations. Using a cultural phylogenetic analysis, I show that a large set of religious behaviors among extant Christian denominations supports the prediction of the recognition signal hypothesis that characters change more frequently near historical schisms. By incorporating demographic data into the model, I show that more-distinctive denominations, as measured through dissimilar characteristics, appear to be protected from intrusion by nonmembers in mixed-denomination households, and that they may be experiencing greater biological growth of their populations even in the present day.

  9. A new non-phagocytic TLR6 with broad recognition ligands from Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Wang, Weilin; Zhang, Tao; Wang, Lingling; Xu, Jiachao; Li, Meijia; Zhang, Anguo; Qiu, Limei; Song, Linsheng

    2016-12-01

    Toll like receptors (TLRs) are evolutionarily prevalent recognition molecules in the Animalia and Plantae kingdom, which play vital roles in immune defense and homeostasis maintenance. Recently, the expansion of TLRs has been reported in invertebrate genomes, but the characters and immune functions of these expanded TLRs were still not well known. In the present study, a new member of TLR family with five LRR domains was identified in Crassostrea gigas (designated CgTLR6). It shared homology with TLRs from other organisms with the closest phylogenic relationship with molluscan TLRs. The recombinant protein of CgTLR6 (rCgTLR6) displayed direct bind activity to gram-negative bacteria Vibrio anguillarum and Vibrio splendidus, gram-positive bacteria Staphylococci aureus and Micrococcus luteus, and fungi Pichia pastoris, but not to fungi Yarrowia lipolytica. It also exhibited affinity to lipopolysaccharide (LPS) and peptidoglycan (PGN), while no affinity to mannan (MAN). The mRNA of CgTLR6 was mainly detected in hemocytes and hepatopancreas, and was significantly induced (p < 0.01) in hemocytes after the oyster was stimulated with LPS, PGN or bacteria V. splendidus. Immunofluorescence analysis indicated that CgTLR6 was mainly located at the membrane of hemocytes. The blockage of CgTLR6 by anti-rCgTLR6 antibody did not significantly inhibit the phagocytic rates of hemocytes toward recognized gram-negative bacteria V. anguillarum and V. splendidus, and unrecognized fungi Y. lipolytica. These results collectively implied that CgTLR6 was a novel non-phagocytic receptor of C. gigas to mediate humoral immune response by recognizing pathogen-associated molecular patterns on the invaders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Recognition

    DEFF Research Database (Denmark)

    Gimmler, Antje

    2017-01-01

    In this article, I shall examine the cognitive, heuristic and theoretical functions of the concept of recognition. To evaluate both the explanatory power and the limitations of a sociological concept, the theory construction must be analysed and its actual productivity for sociological theory must...... be evaluated. In the first section, I will introduce the concept of recognition as a travelling concept playing a role both on the intellectual stage and in real life. In the second section, I will concentrate on the presentation of Honneth’s theory of recognition, emphasizing the construction of the concept...... and its explanatory power. Finally, I will discuss Honneth’s concept in relation to the critique that has been raised, addressing the debate between Honneth and Fraser. In a short conclusion, I will return to the question of the explanatory power of the concept of recognition....

  11. Color Histograms Adapted to Query-Target Images for Object Recognition across Illumination Changes

    Directory of Open Access Journals (Sweden)

    Jack-Gérard Postaire

    2005-08-01

    Full Text Available Most object recognition schemes fail in case of illumination changes between the color image acquisitions. One of the most widely used solutions to cope with this problem is to compare the images by means of the intersection between invariant color histograms. The main originality of our approach is to cope with the problem of illumination changes by analyzing each pair of query and target images constructed during the retrieval, instead of considering each image of the database independently from each other. In this paper, we propose a new approach which determines color histograms adapted to each pair of images. These adapted color histograms are obtained so that their intersection is higher when the two images are similar than when they are different. The adapted color histograms processing is based on an original model of illumination changes based on rank measures of the pixels within the color component images.

  12. An automatic system for Turkish word recognition using Discrete Wavelet Neural Network based on adaptive entropy

    International Nuclear Information System (INIS)

    Avci, E.

    2007-01-01

    In this paper, an automatic system is presented for word recognition using real Turkish word signals. This paper especially deals with combination of the feature extraction and classification from real Turkish word signals. A Discrete Wavelet Neural Network (DWNN) model is used, which consists of two layers: discrete wavelet layer and multi-layer perceptron. The discrete wavelet layer is used for adaptive feature extraction in the time-frequency domain and is composed of Discrete Wavelet Transform (DWT) and wavelet entropy. The multi-layer perceptron used for classification is a feed-forward neural network. The performance of the used system is evaluated by using noisy Turkish word signals. Test results showing the effectiveness of the proposed automatic system are presented in this paper. The rate of correct recognition is about 92.5% for the sample speech signals. (author)

  13. Unstable Morse code recognition with adaptive variable-ratio threshold prediction for physically disabled persons.

    Science.gov (United States)

    Hsieh, M C; Luo, C H; Mao, C W

    2000-09-01

    With one or two switches, Morse code could provide an effective alternative communication channel for individuals with physical limitations. However, most of the physically disabled persons have difficulties in maintaining a stable typing of Morse code, and hence the automated recognition of unstable Morse code is becoming more on demand. In this study, an adaptive variable-ratio threshold prediction (AVRTP) algorithm is proposed to analyze the Morse code time series with variable unit time period and ratio. Two least-mean-square (LMS) predictors are applied to track the dot interval and the dot-dash difference concurrently, and then a predicted threshold based on a variable-ratio decision rule is used to distinguish between dots and dashes. The same method is also applied to identify character-spaces. By the adaptive prediction of variable-ratio threshold, AVRTP has successfully overcome the difficulty of analyzing severely unstable Morse code time series and outperformed the previously proposed adaptive unstable-speed prediction (AUSP) algorithm and LMS and matching (I,MS&M) algorithm. This study concludes with a computer simulation and a preliminary clinical evaluation that demonstrate AVRTP as an efficient and reliable method for unstable Morse code recognition.

  14. A New Adaptive Structural Signature for Symbol Recognition by Using a Galois Lattice as a Classifier.

    Science.gov (United States)

    Coustaty, M; Bertet, K; Visani, M; Ogier, J

    2011-08-01

    In this paper, we propose a new approach for symbol recognition using structural signatures and a Galois lattice as a classifier. The structural signatures are based on topological graphs computed from segments which are extracted from the symbol images by using an adapted Hough transform. These structural signatures-that can be seen as dynamic paths which carry high-level information-are robust toward various transformations. They are classified by using a Galois lattice as a classifier. The performance of the proposed approach is evaluated based on the GREC'03 symbol database, and the experimental results we obtain are encouraging.

  15. MAP Based Speaker Adaptation in Very Large Vocabulary Speech Recognition of Czech

    Directory of Open Access Journals (Sweden)

    J. Nouza

    2004-09-01

    Full Text Available The paper deals with the problem of efficient adaptation of speechrecognition systems to individual users. The goal is to achieve betterperformance in specific applications where one known speaker isexpected. In our approach we adopt the MAP (Maximum A Posteriorimethod for this purpose. The MAP based formulae for the adaptation ofthe HMM (Hidden Markov Model parameters are described. Severalalternative versions of this method have been implemented andexperimentally verified in two areas, first in the isolated-wordrecognition (IWR task and later also in the large vocabularycontinuous speech recognition (LVCSR system, both developed for theCzech language. The results show that the word error rate (WER can bereduced by more than 20% for a speaker who provides tens of words (incase of IWR or tens of sentences (in case of LVCSR for theadaptation. Recently, we have used the described methods in the designof two practical applications: voice dictation to a PC and automatictranscription of radio and TV news.

  16. Real-time task recognition in cataract surgery videos using adaptive spatiotemporal polynomials.

    Science.gov (United States)

    Quellec, Gwénolé; Lamard, Mathieu; Cochener, Béatrice; Cazuguel, Guy

    2015-04-01

    This paper introduces a new algorithm for recognizing surgical tasks in real-time in a video stream. The goal is to communicate information to the surgeon in due time during a video-monitored surgery. The proposed algorithm is applied to cataract surgery, which is the most common eye surgery. To compensate for eye motion and zoom level variations, cataract surgery videos are first normalized. Then, the motion content of short video subsequences is characterized with spatiotemporal polynomials: a multiscale motion characterization based on adaptive spatiotemporal polynomials is presented. The proposed solution is particularly suited to characterize deformable moving objects with fuzzy borders, which are typically found in surgical videos. Given a target surgical task, the system is trained to identify which spatiotemporal polynomials are usually extracted from videos when and only when this task is being performed. These key spatiotemporal polynomials are then searched in new videos to recognize the target surgical task. For improved performances, the system jointly adapts the spatiotemporal polynomial basis and identifies the key spatiotemporal polynomials using the multiple-instance learning paradigm. The proposed system runs in real-time and outperforms the previous solution from our group, both for surgical task recognition ( Az = 0.851 on average, as opposed to Az = 0.794 previously) and for the joint segmentation and recognition of surgical tasks ( Az = 0.856 on average, as opposed to Az = 0.832 previously).

  17. Ligand recognition and domain structure of Vps10p, a vacuolar protein sorting receptor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Jørgensen, M U; Emr, S D; Winther, Jakob R.

    1999-01-01

    Vp10p is a receptor that sorts several different vacuolar proteins by cycling between a late Golgi compartment and the endosome. The cytoplasmic tail of Vps10p is necessary for the recycling, whereas the lumenal domain is predicted to interact with the soluble ligands. We have studied ligand bind...

  18. Sparsity-aware tight frame learning with adaptive subspace recognition for multiple fault diagnosis

    Science.gov (United States)

    Zhang, Han; Chen, Xuefeng; Du, Zhaohui; Yang, Boyuan

    2017-09-01

    It is a challenging problem to design excellent dictionaries to sparsely represent diverse fault information and simultaneously discriminate different fault sources. Therefore, this paper describes and analyzes a novel multiple feature recognition framework which incorporates the tight frame learning technique with an adaptive subspace recognition strategy. The proposed framework consists of four stages. Firstly, by introducing the tight frame constraint into the popular dictionary learning model, the proposed tight frame learning model could be formulated as a nonconvex optimization problem which can be solved by alternatively implementing hard thresholding operation and singular value decomposition. Secondly, the noises are effectively eliminated through transform sparse coding techniques. Thirdly, the denoised signal is decoupled into discriminative feature subspaces by each tight frame filter. Finally, in guidance of elaborately designed fault related sensitive indexes, latent fault feature subspaces can be adaptively recognized and multiple faults are diagnosed simultaneously. Extensive numerical experiments are sequently implemented to investigate the sparsifying capability of the learned tight frame as well as its comprehensive denoising performance. Most importantly, the feasibility and superiority of the proposed framework is verified through performing multiple fault diagnosis of motor bearings. Compared with the state-of-the-art fault detection techniques, some important advantages have been observed: firstly, the proposed framework incorporates the physical prior with the data-driven strategy and naturally multiple fault feature with similar oscillation morphology can be adaptively decoupled. Secondly, the tight frame dictionary directly learned from the noisy observation can significantly promote the sparsity of fault features compared to analytical tight frames. Thirdly, a satisfactory complete signal space description property is guaranteed and thus

  19. Regularized Speaker Adaptation of KL-HMM for Dysarthric Speech Recognition

    Science.gov (United States)

    Kim, Myungjong; Kim, Younggwan; Yoo, Joohong; Wang, Jun; Kim, Hoirin

    2017-01-01

    This paper addresses the problem of recognizing the speech uttered by patients with dysarthria, which is a motor speech disorder impeding the physical production of speech. Patients with dysarthria have articulatory limitation, and therefore, they often have trouble in pronouncing certain sounds, resulting in undesirable phonetic variation. Modern automatic speech recognition systems designed for regular speakers are ineffective for dysarthric sufferers due to the phonetic variation. To capture the phonetic variation, Kullback-Leibler divergence based hidden Markov model (KL-HMM) is adopted, where the emission probability of state is parametrized by a categorical distribution using phoneme posterior probabilities obtained from a deep neural network-based acoustic model. To further reflect speaker-specific phonetic variation patterns, a speaker adaptation method based on a combination of L2 regularization and confusion-reducing regularization which can enhance discriminability between categorical distributions of KL-HMM states while preserving speaker-specific information is proposed. Evaluation of the proposed speaker adaptation method on a database of several hundred words for 30 speakers consisting of 12 mildly dysarthric, 8 moderately dysarthric, and 10 non-dysarthric control speakers showed that the proposed approach significantly outperformed the conventional deep neural network based speaker adapted system on dysarthric as well as non-dysarthric speech. PMID:28320669

  20. Recognition of extracellular bacteria by NLRs and its role in the development of adaptive immunity

    Directory of Open Access Journals (Sweden)

    Jonathan eFerrand

    2013-10-01

    Full Text Available Innate immune recognition of bacteria is the first requirement for mounting an effective immune response able to control infection. Over the previous decade, the general paradigm was that extracellular bacteria were only sensed by cell surface-expressed Toll-like receptors (TLRs, whereas cytoplasmic sensors, including members of the Nod-like receptor (NLR family, were specific to pathogens capable of breaching the host cell membrane. It has become apparent, however, that intracellular innate immune molecules, such as the NLRs, play key roles in the sensing of not only intracellular, but also extracellular bacterial pathogens or their components. In this review, we will discuss the various mechanisms used by bacteria to activate NLR signaling in host cells. These mechanisms include bacterial secretion systems, pore-forming toxins and outer membrane vesicles. We will then focus on the influence of NLR activation on the development of adaptive immune responses in different cell types.

  1. Adaptive algorithm of infrared target enhancement for target recognition of infrared detector

    Science.gov (United States)

    Guo, Jia; Liu, Wei-guo; Gao, Jiao-bo; Qin, Wen-gang

    2009-05-01

    The algorithm of infrared image enhancement directly impacts on the veracity of target recognition. However, traditional histogram equalization and gray-scale transformation algorithms can't realize the enhancement of the target in the infrared image effectively. Consequently, an adaptive algorithm for infrared target enhancement has been presented. The experimental result shows that this algorithm could automatically choose the threshold of histogram segmentation according to the gray characteristic of the target. It can also increase the contrast and decrease the noise while suppressing the background. In addition, this algorithm could be used for target enhancement of other infrared images, and had small computation, especially suitable for real-time processing of infrared images.

  2. Iterative Re-Constrained Group Sparse Face Recognition With Adaptive Weights Learning.

    Science.gov (United States)

    Zheng, Jianwei; Yang, Ping; Chen, Shengyong; Shen, Guojiang; Wang, Wanliang

    2017-05-01

    In this paper, we consider the robust face recognition problem via iterative re-constrained group sparse classifier (IRGSC) with adaptive weights learning. Specifically, we propose a group sparse representation classification (GSRC) approach in which weighted features and groups are collaboratively adopted to encode more structure information and discriminative information than other regression based methods. In addition, we derive an efficient algorithm to optimize the proposed objective function, and theoretically prove the convergence. There are several appealing aspects associated with IRGSC. First, adaptively learned weights can be seamlessly incorporated into the GSRC framework. This integrates the locality structure of the data and validity information of the features into l 2,p -norm regularization to form a unified formulation. Second, IRGSC is very flexible to different size of training set as well as feature dimension thanks to the l 2,p -norm regularization. Third, the derived solution is proved to be a stationary point (globally optimal if p ≥ 1 ). Comprehensive experiments on representative data sets demonstrate that IRGSC is a robust discriminative classifier which significantly improves the performance and efficiency compared with the state-of-the-art methods in dealing with face occlusion, corruption, and illumination changes, and so on.

  3. EEG-Based Emotion Recognition Using Deep Learning Network with Principal Component Based Covariate Shift Adaptation

    Directory of Open Access Journals (Sweden)

    Suwicha Jirayucharoensak

    2014-01-01

    Full Text Available Automatic emotion recognition is one of the most challenging tasks. To detect emotion from nonstationary EEG signals, a sophisticated learning algorithm that can represent high-level abstraction is required. This study proposes the utilization of a deep learning network (DLN to discover unknown feature correlation between input signals that is crucial for the learning task. The DLN is implemented with a stacked autoencoder (SAE using hierarchical feature learning approach. Input features of the network are power spectral densities of 32-channel EEG signals from 32 subjects. To alleviate overfitting problem, principal component analysis (PCA is applied to extract the most important components of initial input features. Furthermore, covariate shift adaptation of the principal components is implemented to minimize the nonstationary effect of EEG signals. Experimental results show that the DLN is capable of classifying three different levels of valence and arousal with accuracy of 49.52% and 46.03%, respectively. Principal component based covariate shift adaptation enhances the respective classification accuracy by 5.55% and 6.53%. Moreover, DLN provides better performance compared to SVM and naive Bayes classifiers.

  4. Conformational changes and ligand recognition of Escherichia coli D-xylose binding protein revealed

    DEFF Research Database (Denmark)

    Sooriyaarachchi, Sanjeewani; Ubhayasekera, Wimal; Park, Chankyu

    2010-01-01

    ATP binding cassette transport systems account for most import of necessary nutrients in bacteria. The periplasmic binding component (or an equivalent membrane-anchored protein) is critical to recognizing cognate ligand and directing it to the appropriate membrane permease. Here we report the X...... of the three different forms from the same protein furthermore gives unprecedented details concerning the conformational changes involved in binding protein function. As is typical of the structural family, the protein has two similar globular domains, which are connected by a three-stranded hinge region...... ordered near the ligand. An analysis of the interactions suggests why xylose is the preferred ligand. Furthermore, a comparison with the most closely related proteins in the structural family shows that the conformational changes are distinct in each type of binding protein, which may have implications...

  5. Adaptive spatial filtering for off-axis digital holographic microscopy based on region recognition approach with iterative thresholding

    Science.gov (United States)

    He, Xuefei; Nguyen, Chuong Vinh; Pratap, Mrinalini; Zheng, Yujie; Wang, Yi; Nisbet, David R.; Rug, Melanie; Maier, Alexander G.; Lee, Woei Ming

    2016-12-01

    Here we propose a region-recognition approach with iterative thresholding, which is adaptively tailored to extract the appropriate region or shape of spatial frequency. In order to justify the method, we tested it with different samples and imaging conditions (different objectives). We demonstrate that our method provides a useful method for rapid imaging of cellular dynamics in microfluidic and cell cultures.

  6. The thermodynamic effects of ligand structure on the molecular recognition of mononuclear ruthenium polypyridyl complexes with B-DNA

    Science.gov (United States)

    The ruthenium(II) polypyridyl complexes (RPCs), [(phen)2Ru(tatpp)]Cl2 (3Cl2) and [(phen)2Ru (tatpp)Ru(phen)2]Cl4 (4Cl4), containing the large planar and redox-active tetraazatetrapyrido- pentacene (tatpp) ligand, cleave DNA in the presence of reducing agents in cell-free assays and show significant...

  7. Recognition of GPCRs by peptide ligands and membrane compartments theory: structural studies of endogenous peptide hormones in membrane environment.

    Science.gov (United States)

    Sankararamakrishnan, Ramasubbu

    2006-04-01

    One of the largest family of cell surface proteins, G-protein coupled receptors (GPCRs) regulate virtually all known physiological processes in mammals. With seven transmembrane segments, they respond to diverse range of extracellular stimuli and represent a major class of drug targets. Peptidergic GPCRs use endogenous peptides as ligands. To understand the mechanism of GPCR activation and rational drug design, knowledge of three-dimensional structure of receptor-ligand complex is important. The endogenous peptide hormones are often short, flexible and completely disordered in aqueous solution. According to "Membrane Compartments Theory", the flexible peptide binds to the membrane in the first step before it recognizes its receptor and the membrane-induced conformation is postulated to bind to the receptor in the second step. Structures of several peptide hormones have been determined in membrane-mimetic medium. In these studies, micelles, reverse micelles and bicelles have been used to mimic the cell membrane environment. Recently, conformations of two peptide hormones have also been studied in receptor-bound form. Membrane environment induces stable secondary structures in flexible peptide ligands and membrane-induced peptide structures have been correlated with their bioactivity. Results of site-directed mutagenesis, spectroscopy and other experimental studies along with the conformations determined in membrane medium have been used to interpret the role of individual residues in the peptide ligand. Structural differences of membrane-bound peptides that belong to the same family but differ in selectivity are likely to explain the mechanism of receptor selectivity and specificity of the ligands. Knowledge of peptide 3D structures in membrane environment has potential applications in rational drug design.

  8. Importance of the extracellular loops in G protein-coupled receptors for ligand recognition and receptor activation.

    Science.gov (United States)

    Peeters, M C; van Westen, G J P; Li, Q; IJzerman, A P

    2011-01-01

    G protein-coupled receptors (GPCRs) are the major drug target of medicines on the market today. Therefore, much research is and has been devoted to the elucidation of the function and three-dimensional structure of this large family of membrane proteins, which includes multiple conserved transmembrane domains connected by intra- and extracellular loops. In the last few years, the less conserved extracellular loops have garnered increasing interest, particularly after the publication of several GPCR crystal structures that clearly show the extracellular loops to be involved in ligand binding. This review will summarize the recent progress made in the clarification of the ligand binding and activation mechanism of class-A GPCRs and the role of extracellular loops in this process. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Ligand recognition and domain structure of Vps10p, a vacuolar protein sorting receptor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Jørgensen, M U; Emr, S D; Winther, Jakob R.

    1999-01-01

    Vp10p is a receptor that sorts several different vacuolar proteins by cycling between a late Golgi compartment and the endosome. The cytoplasmic tail of Vps10p is necessary for the recycling, whereas the lumenal domain is predicted to interact with the soluble ligands. We have studied ligand...... binding to Vps10p by introducing deletions in the lumenal region. This region contains two domains with homology to each other. Domain 2 binds carboxypeptidase Y (CPY), proteinase A (PrA) and hybrids of these proteases with invertase. Moreover, we show that aminopeptidase Y (APY) is a ligand of Vps10p....... The native proteases compete for binding to domain 2. Binding of CPY(156)-invertase or PrA(137)-invertase, on the other hand, do not interfere with binding of CPY to Vps10p. Furthermore, the Q24RPL27 sequence known to be important for vacuolar sorting of CPY, is of little importance in the Vps10p...

  10. Multiple Adaptive Neuro-Fuzzy Inference System with Automatic Features Extraction Algorithm for Cervical Cancer Recognition

    Directory of Open Access Journals (Sweden)

    Mohammad Subhi Al-batah

    2014-01-01

    Full Text Available To date, cancer of uterine cervix is still a leading cause of cancer-related deaths in women worldwide. The current methods (i.e., Pap smear and liquid-based cytology (LBC to screen for cervical cancer are time-consuming and dependent on the skill of the cytopathologist and thus are rather subjective. Therefore, this paper presents an intelligent computer vision system to assist pathologists in overcoming these problems and, consequently, produce more accurate results. The developed system consists of two stages. In the first stage, the automatic features extraction (AFE algorithm is performed. In the second stage, a neuro-fuzzy model called multiple adaptive neuro-fuzzy inference system (MANFIS is proposed for recognition process. The MANFIS contains a set of ANFIS models which are arranged in parallel combination to produce a model with multi-input-multioutput structure. The system is capable of classifying cervical cell image into three groups, namely, normal, low-grade squamous intraepithelial lesion (LSIL and high-grade squamous intraepithelial lesion (HSIL. The experimental results prove the capability of the AFE algorithm to be as effective as the manual extraction by human experts, while the proposed MANFIS produces a good classification performance with 94.2% accuracy.

  11. Pattern recognition with adaptive-thresholds for sleep spindle in high density EEG signals.

    Science.gov (United States)

    Gemignani, Jessica; Agrimi, Jacopo; Cheli, Enrico; Gemignani, Angelo; Laurino, Marco; Allegrini, Paolo; Landi, Alberto; Menicucci, Danilo

    2015-01-01

    Medicine and Surgery, University of Pisa, via Savi 10, 56126, Pisa, Italy Sleep spindles are electroencephalographic oscillations peculiar of non-REM sleep, related to neuronal mechanisms underlying sleep restoration and learning consolidation. Based on their very singular morphology, sleep spindles can be visually recognized and detected, even though this approach can lead to significant mis-detections. For this reason, many efforts have been put in developing a reliable algorithm for spindle automatic detection, and a number of methods, based on different techniques, have been tested via visual validation. This work aims at improving current pattern recognition procedures for sleep spindles detection by taking into account their physiological sources of variability. We provide a method as a synthesis of the current state of art that, improving dynamic threshold adaptation, is able to follow modification of spindle characteristics as a function of sleep depth and inter-subjects variability. The algorithm has been applied to physiological data recorded by a high density EEG in order to perform a validation based on visual inspection and on evaluation of expected results from normal night sleep in healthy subjects.

  12. Multiple adaptive neuro-fuzzy inference system with automatic features extraction algorithm for cervical cancer recognition.

    Science.gov (United States)

    Al-batah, Mohammad Subhi; Isa, Nor Ashidi Mat; Klaib, Mohammad Fadel; Al-Betar, Mohammed Azmi

    2014-01-01

    To date, cancer of uterine cervix is still a leading cause of cancer-related deaths in women worldwide. The current methods (i.e., Pap smear and liquid-based cytology (LBC)) to screen for cervical cancer are time-consuming and dependent on the skill of the cytopathologist and thus are rather subjective. Therefore, this paper presents an intelligent computer vision system to assist pathologists in overcoming these problems and, consequently, produce more accurate results. The developed system consists of two stages. In the first stage, the automatic features extraction (AFE) algorithm is performed. In the second stage, a neuro-fuzzy model called multiple adaptive neuro-fuzzy inference system (MANFIS) is proposed for recognition process. The MANFIS contains a set of ANFIS models which are arranged in parallel combination to produce a model with multi-input-multioutput structure. The system is capable of classifying cervical cell image into three groups, namely, normal, low-grade squamous intraepithelial lesion (LSIL) and high-grade squamous intraepithelial lesion (HSIL). The experimental results prove the capability of the AFE algorithm to be as effective as the manual extraction by human experts, while the proposed MANFIS produces a good classification performance with 94.2% accuracy.

  13. Adaptive metric learning with deep neural networks for video-based facial expression recognition

    Science.gov (United States)

    Liu, Xiaofeng; Ge, Yubin; Yang, Chao; Jia, Ping

    2018-01-01

    Video-based facial expression recognition has become increasingly important for plenty of applications in the real world. Despite that numerous efforts have been made for the single sequence, how to balance the complex distribution of intra- and interclass variations well between sequences has remained a great difficulty in this area. We propose the adaptive (N+M)-tuplet clusters loss function and optimize it with the softmax loss simultaneously in the training phrase. The variations introduced by personal attributes are alleviated using the similarity measurements of multiple samples in the feature space with many fewer comparison times as conventional deep metric learning approaches, which enables the metric calculations for large data applications (e.g., videos). Both the spatial and temporal relations are well explored by a unified framework that consists of an Inception-ResNet network with long short term memory and the two fully connected layer branches structure. Our proposed method has been evaluated with three well-known databases, and the experimental results show that our method outperforms many state-of-the-art approaches.

  14. A fast, open source implementation of adaptive biasing potentials uncovers a ligand design strategy for the chromatin regulator BRD4

    Science.gov (United States)

    Dickson, Bradley M.; de Waal, Parker W.; Ramjan, Zachary H.; Xu, H. Eric; Rothbart, Scott B.

    2016-10-01

    In this communication we introduce an efficient implementation of adaptive biasing that greatly improves the speed of free energy computation in molecular dynamics simulations. We investigated the use of accelerated simulations to inform on compound design using a recently reported and clinically relevant inhibitor of the chromatin regulator BRD4 (bromodomain-containing protein 4). Benchmarking on our local compute cluster, our implementation achieves up to 2.5 times more force calls per day than plumed2. Results of five 1 μs-long simulations are presented, which reveal a conformational switch in the BRD4 inhibitor between a binding competent and incompetent state. Stabilization of the switch led to a -3 kcal/mol improvement of absolute binding free energy. These studies suggest an unexplored ligand design principle and offer new actionable hypotheses for medicinal chemistry efforts against this druggable epigenetic target class.

  15. "Adapted Linear Interaction Energy": A Structure-Based LIE Parametrization for Fast Prediction of Protein-Ligand Affinities.

    Science.gov (United States)

    Linder, Mats; Ranganathan, Anirudh; Brinck, Tore

    2013-02-12

    We present a structure-based parametrization of the Linear Interaction Energy (LIE) method and show that it allows for the prediction of absolute protein-ligand binding energies. We call the new model "Adapted" LIE (ALIE) because the α and β coefficients are defined by system-dependent descriptors and do therefore not require any empirical γ term. The best formulation attains a mean average deviation of 1.8 kcal/mol for a diverse test set and depends on only one fitted parameter. It is robust with respect to additional fitting and cross-validation. We compare this new approach with standard LIE by Åqvist and co-workers and the LIE + γSASA model (initially suggested by Jorgensen and co-workers) against in-house and external data sets and discuss their applicabilities.

  16. Goal-recognition-based adaptive brain-computer interface for navigating immersive robotic systems.

    Science.gov (United States)

    Abu-Alqumsan, Mohammad; Ebert, Felix; Peer, Angelika

    2017-06-01

    This work proposes principled strategies for self-adaptations in EEG-based Brain-computer interfaces (BCIs) as a way out of the bandwidth bottleneck resulting from the considerable mismatch between the low-bandwidth interface and the bandwidth-hungry application, and a way to enable fluent and intuitive interaction in embodiment systems. The main focus is laid upon inferring the hidden target goals of users while navigating in a remote environment as a basis for possible adaptations. To reason about possible user goals, a general user-agnostic Bayesian update rule is devised to be recursively applied upon the arrival of evidences, i.e. user input and user gaze. Experiments were conducted with healthy subjects within robotic embodiment settings to evaluate the proposed method. These experiments varied along three factors: the type of the robot/environment (simulated and physical), the type of the interface (keyboard or BCI), and the way goal recognition (GR) is used to guide a simple shared control (SC) driving scheme. Our results show that the proposed GR algorithm is able to track and infer the hidden user goals with relatively high precision and recall. Further, the realized SC driving scheme benefits from the output of the GR system and is able to reduce the user effort needed to accomplish the assigned tasks. Despite the fact that the BCI requires higher effort compared to the keyboard conditions, most subjects were able to complete the assigned tasks, and the proposed GR system is additionally shown able to handle the uncertainty in user input during SSVEP-based interaction. The SC application of the belief vector indicates that the benefits of the GR module are more pronounced for BCIs, compared to the keyboard interface. Being based on intuitive heuristics that model the behavior of the general population during the execution of navigation tasks, the proposed GR method can be used without prior tuning for the individual users. The proposed methods can be

  17. Goal-recognition-based adaptive brain-computer interface for navigating immersive robotic systems

    Science.gov (United States)

    Abu-Alqumsan, Mohammad; Ebert, Felix; Peer, Angelika

    2017-06-01

    Objective. This work proposes principled strategies for self-adaptations in EEG-based Brain-computer interfaces (BCIs) as a way out of the bandwidth bottleneck resulting from the considerable mismatch between the low-bandwidth interface and the bandwidth-hungry application, and a way to enable fluent and intuitive interaction in embodiment systems. The main focus is laid upon inferring the hidden target goals of users while navigating in a remote environment as a basis for possible adaptations. Approach. To reason about possible user goals, a general user-agnostic Bayesian update rule is devised to be recursively applied upon the arrival of evidences, i.e. user input and user gaze. Experiments were conducted with healthy subjects within robotic embodiment settings to evaluate the proposed method. These experiments varied along three factors: the type of the robot/environment (simulated and physical), the type of the interface (keyboard or BCI), and the way goal recognition (GR) is used to guide a simple shared control (SC) driving scheme. Main results. Our results show that the proposed GR algorithm is able to track and infer the hidden user goals with relatively high precision and recall. Further, the realized SC driving scheme benefits from the output of the GR system and is able to reduce the user effort needed to accomplish the assigned tasks. Despite the fact that the BCI requires higher effort compared to the keyboard conditions, most subjects were able to complete the assigned tasks, and the proposed GR system is additionally shown able to handle the uncertainty in user input during SSVEP-based interaction. The SC application of the belief vector indicates that the benefits of the GR module are more pronounced for BCIs, compared to the keyboard interface. Significance. Being based on intuitive heuristics that model the behavior of the general population during the execution of navigation tasks, the proposed GR method can be used without prior tuning for the

  18. Design of sequence-specific DNA binding ligands that use a two-stranded peptide motif for DNA sequence recognition.

    Science.gov (United States)

    Nikolaev, V A; Grokhovsky, S L; Surovaya, A N; Leinsoo, T A; Sidorova NYu; Zasedatelev, A S; Zhuze, A L; Strahan, G A; Shafer, R H; Gursky, G V

    1996-08-01

    The design and DNA binding activity of beta-structure-forming peptides and netropsin-peptide conjugates are reported. It is found that a pair of peptides-S,S'-bis(Lys-Gly-Val-Cys-Val-NH-NH-Dns)-bridged by an S-S bond binds at least 10 times more strongly to poly(dG).poly(dC) than to poly(dA).poly(dT). This peptide can also discriminate between 5'-GpG-3' and 5'-GpC-3' steps in the DNA minor groove. Based on these observations, new synthetic ligands, bis-netropsins, were constructed in which two netropsin-like fragments were attached by means of short linkers to a pair of peptides-Gly-Cys-Gly- or Val-Cys-Val-bridged by S-S bonds. These compounds possess a composite binding specificity: the peptide chains recognize 5'-GpG-3' steps on DNA, whereas the netropsin-like fragments bind preferentially to runs of 4 AT base pairs. Our data indicate that combining the AT-base-pair specific properties of the netropsin-type structure with the 5'-GpG-3'-specific properties of certain oligopeptides offers a new approach to the synthesis of ligands capable of recognizing mixed sequences of AT- and GC-base pairs in the DNA minor groove. These compounds are potential models for DNA-binding domains in proteins which specifically recognize base pair sequences in the minor groove of DNA.

  19. A versatile polypeptide platform for integrated recognition and reporting: affinity arrays for protein-ligand interaction analysis.

    Science.gov (United States)

    Enander, Karin; Dolphin, Gunnar T; Liedberg, Bo; Lundström, Ingemar; Baltzer, Lars

    2004-05-17

    A molecular platform for protein detection and quantification is reported in which recognition has been integrated with direct monitoring of target-protein binding. The platform is based on a versatile 42-residue helix-loop-helix polypeptide that dimerizes to form four-helix bundles and allows site-selective modification with recognition and reporter elements on the side chains of individually addressable lysine residues. The well-characterized interaction between the model target-protein carbonic anhydrase and its inhibitor benzenesulfonamide was used for a proof-of-concept demonstration. An affinity array was designed where benzenesulfonamide derivatives with aliphatic or oligoglycine spacers and a fluorescent dansyl reporter group were introduced into the scaffold. The affinities of the array members for human carbonic anhydrase II (HCAII) were determined by titration with the target protein and were found to be highly affected by the properties of the spacers (dissociation constant Kd=0.02-3 microM). The affinity of HCAII for acetazolamide (Kd=4 nM) was determined in a competition experiment with one of the benzenesulfonamide array members to address the possibility of screening substance libraries for new target-protein binders. Also, successful affinity discrimination between different carbonic anhydrase isozymes highlighted the possibility of performing future isoform-expression profiling. Our platform is predicted to become a flexible tool for a variety of biosensor and protein-microarray applications within biochemistry, diagnostics and pharmaceutical chemistry.

  20. Post-translational modifications modulate ligand recognition by the third PDZ domain of the MAGUK protein PSD-95.

    Directory of Open Access Journals (Sweden)

    Javier Murciano-Calles

    Full Text Available The relative promiscuity of hub proteins such as postsynaptic density protein-95 (PSD-95 can be achieved by alternative splicing, allosteric regulation, and post-translational modifications, the latter of which is the most efficient method of accelerating cellular responses to environmental changes in vivo. Here, a mutational approach was used to determine the impact of phosphorylation and succinimidation post-translational modifications on the binding affinity of the postsynaptic density protein-95/discs large/zonula occludens-1 (PDZ3 domain of PSD-95. Molecular dynamics simulations revealed that the binding affinity of this domain is influenced by an interplay between salt-bridges linking the α3 helix, the β2-β3 loop and the positively charged Lys residues in its high-affinity hexapeptide ligand KKETAV. The α3 helix is an extra structural element that is not present in other PDZ domains, which links PDZ3 with the following SH3 domain in the PSD-95 protein. This regulatory mechanism was confirmed experimentally via thermodynamic and NMR chemical shift perturbation analyses, discarding intra-domain long-range effects. Taken together, the results presented here reveal the molecular basis of the regulatory role of the α3 extra-element and the effects of post-translational modifications of PDZ3 on its binding affinity, both energetically and dynamically.

  1. Selecting Informative Features of the Helicopter and Aircraft Acoustic Signals in the Adaptive Autonomous Information Systems for Recognition

    Directory of Open Access Journals (Sweden)

    V. K. Hohlov

    2017-01-01

    Full Text Available The article forms the rationale for selecting the informative features of the helicopter and aircraft acoustic signals to solve a problem of their recognition and shows that the most informative ones are the counts of extrema in the energy spectra of the input signals, which represent non-centered random variables. An apparatus of the multiple initial regression coefficients was selected as a mathematical tool of research. The application of digital re-circulators with positive and negative feedbacks, which have the comb-like frequency characteristics, solves the problem of selecting informative features. A distinguishing feature of such an approach is easy agility of the comb frequency characteristics just through the agility of a delay value of digital signal in the feedback circuit. Adding an adaptation block to the selection block of the informative features enables us to ensure the invariance of used informative feature and counts of local extrema of the spectral power density to the airspeed of a helicopter. The paper gives reasons for the principle of adaptation and the structure of the adaptation block. To form the discriminator characteristics are used the cross-correlation statistical characteristics of the quadrature components of acoustic signal realizations, obtained by Hilbert transform. The paper proposes to provide signal recognition using a regression algorithm that allows handling the non-centered informative features and using a priori information about coefficients of initial regression of signal and noise.The simulation in Matlab Simulink has shown that selected informative features of signals in regressive processing of signal realizations of 0.5 s duration have good separability, and based on a set of 100 acoustic signal realizations in each class in full-scale conditions, has proved ensuring a correct recognition probability of 0.975, at least. The considered principles of informative features selection and adaptation can

  2. Handwritten Devanagari Character Recognition Using Layer-Wise Training of Deep Convolutional Neural Networks and Adaptive Gradient Methods

    Directory of Open Access Journals (Sweden)

    Mahesh Jangid

    2018-02-01

    Full Text Available Handwritten character recognition is currently getting the attention of researchers because of possible applications in assisting technology for blind and visually impaired users, human–robot interaction, automatic data entry for business documents, etc. In this work, we propose a technique to recognize handwritten Devanagari characters using deep convolutional neural networks (DCNN which are one of the recent techniques adopted from the deep learning community. We experimented the ISIDCHAR database provided by (Information Sharing Index ISI, Kolkata and V2DMDCHAR database with six different architectures of DCNN to evaluate the performance and also investigate the use of six recently developed adaptive gradient methods. A layer-wise technique of DCNN has been employed that helped to achieve the highest recognition accuracy and also get a faster convergence rate. The results of layer-wise-trained DCNN are favorable in comparison with those achieved by a shallow technique of handcrafted features and standard DCNN.

  3. Enhanced resolution of molecular recognition to distinguish structurally similar molecules by different conformational responses of a protein upon ligand binding.

    Science.gov (United States)

    Higuchi, Mariko; Fujii, Jumpei; Yonetani, Yoshiteru; Kitao, Akio; Go, Nobuhiro

    2011-01-01

    MutT distinguishes substrate 8-oxo-dGTP from dGTP and also 8-oxo-dGMP from dGMP despite small differences of chemical structures between them. In this paper we show by the method of molecular dynamics simulation that the transition between conformational substates of MutT is a key mechanism for a high-resolution molecular recognition of the differences between the very similar chemical compounds. (1) The native state MutT has two conformational substates with similar free energies, each characterized by either open or closed of two loops surrounding the substrate binding active site. Between the two substates, the open substate is more stable in free MutT and in dGMP-MutT complex, and the closed substate is more stable in 8-oxo-dGMP-MutT complex. (2) Conformational fluctuation of the open substate is much larger than that of the closed substate. An estimate of associated entropy difference was found to be consistent with the experimentally found difference of entropy contribution to the binding free energies of the two molecules. (3) A hydrogen bond between H7 atom of 8-oxo-dGMP and the sidechain of Asn119 plays a crucial role for maintaining the closed substate in 8-oxo-dGMP-MutT complex. When this hydrogen bond is absent in the H7-deficient dGMP-MutT complex, the closed substate is no more maintained and transition to the more entropically-favored open substate is induced. (4) Thus, this mechanism of the hydrogen bond controlling the relative stabilities of the drastically different two conformational substates enhances the resolution to recognize the small difference of the chemical structures between the two molecules, dGMP and 8-oxo-dGMP. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. Adaptive Liquid Crystal TV Based Joint Transform Correlator as Applied to Real-Time Pattern Recognition

    Science.gov (United States)

    1991-05-23

    zero-order 9 K. Fukunaga. Introduction to Statsttcal Pattern Recognition, Ac- dithfcrlation outputdc) is showntiny Figue. whreero-ord- ademic . New York...Snget pioesle aveatesiof epihlusda P, by ab nou e onsrtinwe ae caund beha realor b ursngak pogram the ratinllgtwheriemxmted urm r oogixms of the LoOt a

  5. Adaptive weighted local textural features for illumination, expression, and occlusion invariant face recognition

    Science.gov (United States)

    Cui, Chen; Asari, Vijayan K.

    2014-03-01

    Biometric features such as fingerprints, iris patterns, and face features help to identify people and restrict access to secure areas by performing advanced pattern analysis and matching. Face recognition is one of the most promising biometric methodologies for human identification in a non-cooperative security environment. However, the recognition results obtained by face recognition systems are a affected by several variations that may happen to the patterns in an unrestricted environment. As a result, several algorithms have been developed for extracting different facial features for face recognition. Due to the various possible challenges of data captured at different lighting conditions, viewing angles, facial expressions, and partial occlusions in natural environmental conditions, automatic facial recognition still remains as a difficult issue that needs to be resolved. In this paper, we propose a novel approach to tackling some of these issues by analyzing the local textural descriptions for facial feature representation. The textural information is extracted by an enhanced local binary pattern (ELBP) description of all the local regions of the face. The relationship of each pixel with respect to its neighborhood is extracted and employed to calculate the new representation. ELBP reconstructs a much better textural feature extraction vector from an original gray level image in different lighting conditions. The dimensionality of the texture image is reduced by principal component analysis performed on each local face region. Each low dimensional vector representing a local region is now weighted based on the significance of the sub-region. The weight of each sub-region is determined by employing the local variance estimate of the respective region, which represents the significance of the region. The final facial textural feature vector is obtained by concatenating the reduced dimensional weight sets of all the modules (sub-regions) of the face image

  6. Molecular adaptation in flowering and symbiotic recognition pathways: insights from patterns of polymorphism in the legume Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Ronfort Joëlle

    2011-08-01

    Full Text Available Abstract Background We studied patterns of molecular adaptation in the wild Mediterranean legume Medicago truncatula. We focused on two phenotypic traits that are not functionally linked: flowering time and perception of symbiotic microbes. Phenology is an important fitness component, especially for annual plants, and many instances of molecular adaptation have been reported for genes involved in flowering pathways. While perception of symbiotic microbes is also integral to adaptation in many plant species, very few reports of molecular adaptation exist for symbiotic genes. Here we used data from 57 individuals and 53 gene fragments to quantify the overall strength of both positive and purifying selection in M. truncatula and asked if footprints of positive selection can be detected at key genes of rhizobia recognition pathways. Results We examined nucleotide variation among 57 accessions from natural populations in 53 gene fragments: 5 genes involved in nitrogen-fixing bacteria recognition, 11 genes involved in flowering, and 37 genes used as control loci. We detected 1757 polymorphic sites yielding an average nucleotide diversity (pi of 0.003 per site. Non-synonymous variation is under sizable purifying selection with 90% of amino-acid changing mutations being strongly selected against. Accessions were structured in two groups consistent with geographical origins. Each of these two groups harboured an excess of rare alleles, relative to expectations of a constant-sized population, suggesting recent population expansion. Using coalescent simulations and an approximate Bayesian computation framework we detected several instances of genes departing from selective neutrality within each group and showed that the polymorphism of two nodulation and four flowering genes has probably been shaped by recent positive selection. Conclusion We quantify the intensity of purifying selection in the M. truncatula genome and show that putative footprints of

  7. User adaptation in long-term, open-loop myoelectric training: implications for EMG pattern recognition in prosthesis control

    Science.gov (United States)

    He, Jiayuan; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Farina, Dario; Zhu, Xiangyang

    2015-08-01

    Objective. Recent studies have reported that the classification performance of electromyographic (EMG) signals degrades over time without proper classification retraining. This problem is relevant for the applications of EMG pattern recognition in the control of active prostheses. Approach. In this study we investigated the changes in EMG classification performance over 11 consecutive days in eight able-bodied subjects and two amputees. Main results. It was observed that, when the classifier was trained on data from one day and tested on data from the following day, the classification error decreased exponentially but plateaued after four days for able-bodied subjects and six to nine days for amputees. The between-day performance became gradually closer to the corresponding within-day performance. Significance. These results indicate that the relative changes in EMG signal features over time become progressively smaller when the number of days during which the subjects perform the pre-defined motions are increased. The performance of the motor tasks is thus more consistent over time, resulting in more repeatable EMG patterns, even if the subjects do not have any external feedback on their performance. The learning curves for both able-bodied subjects and subjects with limb deficiencies could be modeled as an exponential function. These results provide important insights into the user adaptation characteristics during practical long-term myoelectric control applications, with implications for the design of an adaptive pattern recognition system.

  8. Local binary pattern variants-based adaptive texture features analysis for posed and nonposed facial expression recognition

    Science.gov (United States)

    Sultana, Maryam; Bhatti, Naeem; Javed, Sajid; Jung, Soon Ki

    2017-09-01

    Facial expression recognition (FER) is an important task for various computer vision applications. The task becomes challenging when it requires the detection and encoding of macro- and micropatterns of facial expressions. We present a two-stage texture feature extraction framework based on the local binary pattern (LBP) variants and evaluate its significance in recognizing posed and nonposed facial expressions. We focus on the parametric limitations of the LBP variants and investigate their effects for optimal FER. The size of the local neighborhood is an important parameter of the LBP technique for its extraction in images. To make the LBP adaptive, we exploit the granulometric information of the facial images to find the local neighborhood size for the extraction of center-symmetric LBP (CS-LBP) features. Our two-stage texture representations consist of an LBP variant and the adaptive CS-LBP features. Among the presented two-stage texture feature extractions, the binarized statistical image features and adaptive CS-LBP features were found showing high FER rates. Evaluation of the adaptive texture features shows competitive and higher performance than the nonadaptive features and other state-of-the-art approaches, respectively.

  9. Adaptive pattern recognition in real-time video-based soccer analysis

    DEFF Research Database (Denmark)

    Schlipsing, Marc; Salmen, Jan; Tschentscher, Marc

    2017-01-01

    Computer-aided sports analysis is demanded by coaches and the media. Image processing and machine learning techniques that allow for "live" recognition and tracking of players exist. But these methods are far from collecting and analyzing event data fully autonomously. To generate accurate results......, human interaction is required at different stages including system setup, calibration, supervision of classifier training, and resolution of tracking conflicts. Furthermore, the real-time constraints are challenging: in contrast to other object recognition and tracking applications, we cannot treat data...... collection, annotation, and learning as an offline task. A semi-automatic labeling of training data and robust learning given few examples from unbalanced classes are required. We present a real-time system acquiring and analyzing video sequences from soccer matches. It estimates each player's position...

  10. Using self-organizing maps adaptive resonance theory (CARTMAP) for manufacturing feature recognition

    Science.gov (United States)

    Yu, Jason S.; Dagli, Cihan H.

    1993-10-01

    The invariant image preprocessing of moment invariants generates an invariant representation of object features which are insensitive to position, orientation, size, illusion, and contrast change. In this study ARTMAP is used for 3-D object recognition of manufacturing parts through these invariant characteristics. The analog of moment invariants created through the image preprocessing is interpreted by a binary code which is used to predict the manufacturing part through ARTMAP.

  11. OX40 ligand expressed in glioblastoma modulates adaptive immunity depending on the microenvironment: a clue for successful immunotherapy.

    Science.gov (United States)

    Shibahara, Ichiyo; Saito, Ryuta; Zhang, Rong; Chonan, Masashi; Shoji, Takuhiro; Kanamori, Masayuki; Sonoda, Yukihiko; Kumabe, Toshihiro; Kanehira, Masahiko; Kikuchi, Toshiaki; So, Takanori; Watanabe, Takashi; Takahashi, Hiroaki; Iwabuchi, Erina; Tanaka, Yuetsu; Shibahara, Yukiko; Sasano, Hironobu; Ishii, Naoto; Tominaga, Teiji

    2015-02-15

    Glioblastoma is the most malignant human brain tumor and has a dismal prognosis; however, some patients show long-term survival. The interaction between the costimulatory molecule OX40 and its ligand OX40L generates key signals for T-cell activation. The augmentation of this interaction enhances antitumor immunity. In this present study, we explored whether OX40 signaling is responsible for antitumor adaptive immunity against glioblastoma and also established therapeutic antiglioma vaccination therapy. Tumor specimens were obtained from patients with primary glioblastoma (n = 110) and grade III glioma (n = 34). Quantitative polymerase chain reaction (PCR), flow cytometry, and immunohistochemistry were used to analyze OX40L expression in human glioblastoma specimens. Functional consequences of OX40 signaling were studied using glioblastoma cell lines, mouse models of glioma, and T cells isolated from human subjects and mice. Cytokine production assay with mouse regulatory T cells was conducted under hypoxic conditions (1.5% O2). OX40L mRNA was expressed in glioblastoma specimens and higher levels were associated with prolonged progression-free survival of patients with glioblastoma, who had undergone gross total resection. In this regard, OX40L protein was expressed in A172 human glioblastoma cells and its expression was induced under hypoxia, which mimics the microenvironment of glioblastoma. Notably, human CD4 T cells were activated when cocultured in anti-CD3-coated plates with A172 cells expressing OX40L, as judged by the increased production of interferon-γ. To confirm the survival advantage of OX40L expression, we then used mouse glioma models. Mice bearing glioma cells forced to express OX40L did not die during the observed period after intracranial transplantation, whereas all mice bearing glioma cells lacking OX40L died. Such a survival benefit of OX40L was not detected in nude mice with an impaired immune system. Moreover, compared with systemic

  12. Multiresolution stroke sketch adaptive representation and neural network processing system for gray-level image recognition

    Science.gov (United States)

    Meystel, Alexander M.; Rybak, Ilya A.; Bhasin, Sanjay

    1992-11-01

    This paper describes a method for multiresolutional representation of gray-level images as hierarchial sets of strokes characterizing forms of objects with different degrees of generalization depending on the context of the image. This method transforms the original image into a hierarchical graph which allows for efficient coding in order to store, retrieve, and recognize the image. The method which is described is based upon finding the resolution levels for each image which minimizes the computations required. This becomes possible because of the use of a special image representation technique called Multiresolutional Attentional Representation for Recognition, based upon a feature which the authors call a stroke. This feature turns out to be efficient in the process of finding the appropriate system of resolutions and construction of the relational graph. Multiresolutional Attentional Representation for Recognition (MARR) is formed by a multi-layer neural network with recurrent inhibitory connections between neurons, the receptive fields of which are selectively tuned to detect the orientation of local contrasts in parts of the image with appropriate degree of generalization. This method simulates the 'coarse-to-fine' algorithm which an artist usually uses, making at attentional sketch of real images. The method, algorithms, and neural network architecture in this system can be used in many machine-vision systems with AI properties; in particular, robotic vision. We expect that systems with MARR can become a component of intelligent control systems for autonomous robots. Their architectures are mostly multiresolutional and match well with the multiple resolutions of the MARR structure.

  13. Cluster-Based Adaptation Using Density Forest for HMM Phone Recognition

    DEFF Research Database (Denmark)

    Abou-Zleikha, Mohamed; Tan, Zheng-Hua; Christensen, Mads Græsbøll

    2014-01-01

    the data of each leaf (cluster) in each tree with the corresponding GMM adapted by the leaf data using the MAP method. The results show that the proposed approach achieves 3:8% (absolute) lower phone error rate compared with the standard HMM/GMM and 0:8% (absolute) lower PER compared with bagged HMM/GMM....

  14. Electromyography (EMG) signal recognition using combined discrete wavelet transform based adaptive neuro-fuzzy inference systems (ANFIS)

    Science.gov (United States)

    Arozi, Moh; Putri, Farika T.; Ariyanto, Mochammad; Khusnul Ari, M.; Munadi, Setiawan, Joga D.

    2017-01-01

    People with disabilities are increasing from year to year either due to congenital factors, sickness, accident factors and war. One form of disability is the case of interruptions of hand function. The condition requires and encourages the search for solutions in the form of creating an artificial hand with the ability as a human hand. The development of science in the field of neuroscience currently allows the use of electromyography (EMG) to control the motion of artificial prosthetic hand into the necessary use of EMG as an input signal to control artificial prosthetic hand. This study is the beginning of a significant research planned in the development of artificial prosthetic hand with EMG signal input. This initial research focused on the study of EMG signal recognition. Preliminary results show that the EMG signal recognition using combined discrete wavelet transform and Adaptive Neuro-Fuzzy Inference System (ANFIS) produces accuracy 98.3 % for training and 98.51% for testing. Thus the results can be used as an input signal for Simulink block diagram of a prosthetic hand that will be developed on next study. The research will proceed with the construction of artificial prosthetic hand along with Simulink program controlling and integrating everything into one system.

  15. Molecular recognition of poly(A) by small ligands: an alternative method of analysis reveals nanomolar, cooperative and shape-selective binding.

    Science.gov (United States)

    Cetinkol, Ozgül Persil; Hud, Nicholas V

    2009-02-01

    A few drug-like molecules have recently been found to bind poly(A) and induce a stable secondary structure (T(m) approximately 60 degrees C), even though this RNA homopolymer is single-stranded in the absence of a ligand. Here, we report results from experiments specifically designed to explore the association of small molecules with poly(A). We demonstrate that coralyne, the first small molecule discovered to bind poly(dA), binds with unexpectedly high affinity (K(a) >10(7) M(-1)), and that the crescent shape of coralyne appears necessary for poly(A) binding. We also show that the binding of similar ligands to poly(A) can be highly cooperative. For one particular ligand, at least six ligand molecules are required to stabilize the poly(A) self-structure at room temperature. This highly cooperative binding produces very sharp transitions between unstructured and structured poly(A) as a function of ligand concentration. Given the fact that junctions between Watson-Crick and A.A duplexes are tolerated, we propose that poly(A) sequence elements and appropriate ligands could be used to reversibly drive transitions in DNA and RNA-based molecular structures by simply diluting/concentrating a sample about the poly(A)-ligand 'critical concentration'. The ligands described here may also find biological or medicinal applications, owing to the 3'-polyadenylation of mRNA in living cells.

  16. Adaptive fuzzy leader clustering of complex data sets in pattern recognition

    Science.gov (United States)

    Newton, Scott C.; Pemmaraju, Surya; Mitra, Sunanda

    1992-01-01

    A modular, unsupervised neural network architecture for clustering and classification of complex data sets is presented. The adaptive fuzzy leader clustering (AFLC) architecture is a hybrid neural-fuzzy system that learns on-line in a stable and efficient manner. The initial classification is performed in two stages: a simple competitive stage and a distance metric comparison stage. The cluster prototypes are then incrementally updated by relocating the centroid positions from fuzzy C-means system equations for the centroids and the membership values. The AFLC algorithm is applied to the Anderson Iris data and laser-luminescent fingerprint image data. It is concluded that the AFLC algorithm successfully classifies features extracted from real data, discrete or continuous.

  17. Method for inshore ship detection based on feature recognition and adaptive background window

    Science.gov (United States)

    Zhao, Hongyu; Wang, Quan; Huang, Jingjian; Wu, Weiwei; Yuan, Naichang

    2014-01-01

    Inshore ship detection in synthetic aperture radar (SAR) images is a challenging task. We present an inshore ship detection method based on the characteristics of inshore ships. We first use the Markov random field (MRF) method to segment water and land, and then extract the feature points of inshore ships using polygonal approximation. Following this, we propose new rules for inshore ship extraction and use these rules to separate inshore ships from the land in binary images. Finally, we utilize the adaptive background window (ABW) to complete the clutter statistic and successfully detect inshore ships using a constant false alarm rate (CFAR) detector with ABW and G0 distribution. Experimental results using SAR images show that our method is more accurate than traditional CFAR detection based on K-distribution (K-CFAR), given the same CFAR, and that the quality of the image obtained through our method is higher than that of the traditional K-CFAR detection method by a factor of 0.165. Our method accurately locates and detects inshore ships in complicated environments and thus is more practical for inshore ship detection.

  18. Adaptive pattern recognition by mini-max neural networks as a part of an intelligent processor

    Science.gov (United States)

    Szu, Harold H.

    1990-01-01

    In this decade and progressing into 21st Century, NASA will have missions including Space Station and the Earth related Planet Sciences. To support these missions, a high degree of sophistication in machine automation and an increasing amount of data processing throughput rate are necessary. Meeting these challenges requires intelligent machines, designed to support the necessary automations in a remote space and hazardous environment. There are two approaches to designing these intelligent machines. One of these is the knowledge-based expert system approach, namely AI. The other is a non-rule approach based on parallel and distributed computing for adaptive fault-tolerances, namely Neural or Natural Intelligence (NI). The union of AI and NI is the solution to the problem stated above. The NI segment of this unit extracts features automatically by applying Cauchy simulated annealing to a mini-max cost energy function. The feature discovered by NI can then be passed to the AI system for future processing, and vice versa. This passing increases reliability, for AI can follow the NI formulated algorithm exactly, and can provide the context knowledge base as the constraints of neurocomputing. The mini-max cost function that solves the unknown feature can furthermore give us a top-down architectural design of neural networks by means of Taylor series expansion of the cost function. A typical mini-max cost function consists of the sample variance of each class in the numerator, and separation of the center of each class in the denominator. Thus, when the total cost energy is minimized, the conflicting goals of intraclass clustering and interclass segregation are achieved simultaneously.

  19. Allele-specific recognition by LILRB3 and LILRA6 of a cytokeratin 8-associated ligand on necrotic glandular epithelial cells.

    Science.gov (United States)

    Jones, Des C; Hewitt, Colin R A; López-Álvarez, María R; Jahnke, Martin; Russell, Alasdair I; Radjabova, Valeria; Trowsdale, Alice R Z; Trowsdale, John

    2016-03-29

    The LILRs are a family of receptors that regulate the activities of myelomonocytic cells. We found that specific allelic variants of two related members of the LILR family, LILRB3 and LILRA6, interact with a ligand exposed on necrotic glandular epithelial cells. The extracellular domains of LILRB3 and LILRA6 are very similar and their genes are highly polymorphic. A commonly occurring allele, LILRB3*12, displayed particularly strong binding of these necrotic cells and further screening of the products of LILRB3 alleles identified motifs that correlated with binding. Immunoprecipitation of the ligand from epithelial cell lysates using recombinant LILRB3*12, identified cytokeratins 8, 18 and 19. Purified proteins obtained from epithelial cell lysates, using anti-cytokeratin 8 antibodies, were able to activate LILRB3*12 reporter cells. Knock-down of cytokeratin 8 in epithelial cells abrogated expression of the LILRB3 ligand, while staining with recombinant LILRB3*12 showed co-localisation with cytokeratin 8 and 18 in permeabilised breast cancer cells. Necrosis is a common feature of tumours. The finding of a necrosis-associated ligand for these two receptors raises the possibility of a novel interaction that alters immune responses within the tumour microenvironment. Since LILRB3 and LILRA6 genes are highly polymorphic the interaction may influence an individual's immune response to tumours.

  20. Allele-specific recognition by LILRB3 and LILRA6 of a cytokeratin 8 - associated ligand on necrotic glandular epithelial cells

    OpenAIRE

    Jones, Des C.; Hewitt, Colin R.A.; L?pez-?lvarez, Mar?a R.; Jahnke, Martin; Russell, Alasdair I.; Radjabova, Valeria; Trowsdale, Alice R.Z.; Trowsdale, John

    2016-01-01

    The LILRs are a family of receptors that regulate the activities of myelomonocytic cells. We found that specific allelic variants of two related members of the LILR family, LILRB3 and LILRA6, interact with a ligand exposed on necrotic glandular epithelial cells. The extracellular domains of LILRB3 and LILRA6 are very similar and their genes are highly polymorphic. A commonly occurring allele, LILRB3*12, displayed particularly strong binding of these necrotic cells and further screening of the...

  1. Evaluation of Speech Recognition of Cochlear Implant Recipients Using Adaptive, Digital Remote Microphone Technology and a Speech Enhancement Sound Processing Algorithm.

    Science.gov (United States)

    Wolfe, Jace; Morais, Mila; Schafer, Erin; Agrawal, Smita; Koch, Dawn

    2015-05-01

    Cochlear implant recipients often experience difficulty with understanding speech in the presence of noise. Cochlear implant manufacturers have developed sound processing algorithms designed to improve speech recognition in noise, and research has shown these technologies to be effective. Remote microphone technology utilizing adaptive, digital wireless radio transmission has also been shown to provide significant improvement in speech recognition in noise. There are no studies examining the potential improvement in speech recognition in noise when these two technologies are used simultaneously. The goal of this study was to evaluate the potential benefits and limitations associated with the simultaneous use of a sound processing algorithm designed to improve performance in noise (Advanced Bionics ClearVoice) and a remote microphone system that incorporates adaptive, digital wireless radio transmission (Phonak Roger). A two-by-two way repeated measures design was used to examine performance differences obtained without these technologies compared to the use of each technology separately as well as the simultaneous use of both technologies. Eleven Advanced Bionics (AB) cochlear implant recipients, ages 11 to 68 yr. AzBio sentence recognition was measured in quiet and in the presence of classroom noise ranging in level from 50 to 80 dBA in 5-dB steps. Performance was evaluated in four conditions: (1) No ClearVoice and no Roger, (2) ClearVoice enabled without the use of Roger, (3) ClearVoice disabled with Roger enabled, and (4) simultaneous use of ClearVoice and Roger. Speech recognition in quiet was better than speech recognition in noise for all conditions. Use of ClearVoice and Roger each provided significant improvement in speech recognition in noise. The best performance in noise was obtained with the simultaneous use of ClearVoice and Roger. ClearVoice and Roger technology each improves speech recognition in noise, particularly when used at the same time

  2. A fast, open source implementation of adaptive biasing potentials uncovers a ligand design strategy for the chromatin regulator BRD4

    OpenAIRE

    Dickson, Bradley M.; de Waal, Parker W; Ramjan, Zachary H; Xu, H Eric; Rothbart, Scott B.

    2016-01-01

    In this communication we introduce an efficient implementation of adaptive biasing that greatly improves the speed of free energy computation in molecular dynamics simulations. We investigated the use of accelerated simulations to inform on compound design using a recently reported and clinically relevant inhibitor of the chromatin regulator BRD4 (bromodomain-containing protein 4). Benchmarking on our local compute cluster, our implementation achieves up to 2.5 times more force calls per day ...

  3. Switching of bacterial adhesion to a glycosylated surface by reversible reorientation of the carbohydrate ligand

    DEFF Research Database (Denmark)

    Weber, Theresa; Chrasekaran, Vijayan; Stamer, Insa

    2014-01-01

    The surface recognition in many biological systems is guided by the interaction of carbohydrate-specific proteins (lectins) with carbohydrate epitopes (ligands) located within the unordered glycoconjugate layer (glycocalyx) of cells. Thus, for recognition, the respective ligand has to reorient...

  4. Near infrared fluorescent dual ligand functionalized Au NCs based multidimensional sensor array for pattern recognition of multiple proteins and serum discrimination.

    Science.gov (United States)

    Xu, Shenghao; Gao, Teng; Feng, Xiuying; Fan, Xiaojian; Liu, Gufan; Mao, Yaning; Yu, Xijuan; Lin, Jiehua; Luo, Xiliang

    2017-11-15

    Here, a multidimensional sensor array capable of analyzing various proteins and discriminating between serums from different stages of breast cancer patients were developed based on six kinds of near infrared fluorescent dual ligand functionalized Au NCs (functionalized with different amino acids) as sensing receptors. These six kinds of different amino acids functionalized Au NCs were synthesized for the first time within 2h due to the direct donation of delocalized electrons of electron-rich atoms or groups of the ligands to the Au core. Based on this, ten proteins could be simultaneously and effectively discriminated by this "chemical nose/tongue" sensor array. Linear discrimination analysis (LDA) of the response patterns showed successful differentiation of the analytes at concentrations as low as 10nM with high identification accuracy. Isothermal titration calorimetry (ITC) experiment illustrates that Au NCs interacted with proteins mainly by hydrogen bonding and van der Waals forces. Furthermore, the greatest highlight of this sensor array is demonstrated by successfully discriminating between serums from different stages of breast cancer patients (early, middle and late) and healthy people, suggesting great potential for auxiliary diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. HybridSim-VS: a web server for large-scale ligand-based virtual screening using hybrid similarity recognition techniques.

    Science.gov (United States)

    Shang, Jinling; Dai, Xi; Li, Yecheng; Pistolozzi, Marco; Wang, Ling

    2017-11-01

    Molecular-similarity searches based on two-dimensional (2D) fingerprint and three-dimensional (3D) shape represent two widely used ligand-based virtual screening (VS) methods in computer-aided drug design. 2D fingerprint-based VS utilizes the binary fragment information on a known ligand, whereas 3D shape-based VS takes advantage of geometric information for predefined features from a 3D conformation. Given their different advantages, it would be desirable to hybridize 2D fingerprint and 3D shape molecular-similarity approaches in drug discovery. Here, we presented a general hybrid molecular-similarity protocol, referred to as HybridSim, obtained by combining the 2D fingerprint- and 3D shape-based similarity search methods and evaluated its performance on 595,036 actives and decoys for 40 pharmaceutically relevant targets available in the Directory of Useful Decoys Enhanced (DUD-E). Our results showed that HybridSim significantly improved the overall performance in 40 VS projects as compared with using only 2D fingerprint and 3D shape methods. Furthermore, HybridSim-VS, the first online platform using the proposed HybridSim method coupled with 17,839,945 screenable and purchasable compounds, was developed to provide large-scale and proficient VS capabilities to experts and nonexperts in the field. HybridSim-VS web server is freely available at http://www.rcidm.org/HybridSim-VS/. lingwang@scut.edu.cn. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  6. Adjuvant effects of invariant NKT cell ligand potentiates the innate and adaptive immunity to an inactivated H1N1 swine influenza virus vaccine in pigs.

    Science.gov (United States)

    Dwivedi, Varun; Manickam, Cordelia; Dhakal, Santosh; Binjawadagi, Basavaraj; Ouyang, Kang; Hiremath, Jagadish; Khatri, Mahesh; Hague, Jacquelyn Gervay; Lee, Chang Won; Renukaradhya, Gourapura J

    2016-04-15

    Pigs are considered as the source of some of the emerging human flu viruses. Inactivated swine influenza virus (SwIV) vaccine has been in use in the US swine herds, but it failed to control the flu outbreaks. The main reason has been attributed to lack of induction of strong local mucosal immunity in the respiratory tract. Invariant natural killer T (iNKT) cell is a unique T cell subset, and activation of iNKT cell using its ligand α-Galactosylceramide (α-GalCer) has been shown to potentiate the cross-protective immunity to inactivated influenza virus vaccine candidates in mice. Recently, we discovered iNKT cell in pig and demonstrated its activation using α-GalCer. In this study, we evaluated the efficacy of an inactivated H1N1 SwIV coadministered with α-GalCer intranasally against a homologous viral challenge. Our results demonstrated the potent adjuvant effects of α-GalCer in potentiating both innate and adaptive immune responses to SwIV Ags in the lungs of pigs, which resulted in reduction in the lung viral load by 3 logs compared to without adjuvant. Immunologically, in the lungs of pigs vaccinated with α-GalCer an increased virus specific IgA response, IFN-α secretion and NK cell-cytotoxicity was observed. In addition, iNKT cell-stimulation enhanced the secretion of Th1 cytokines (IFN-γ and IL-12) and reduced the production of immunosuppressive cytokines (IL-10 and TGF-β) in the lungs of pigs⋅ In conclusion, we demonstrated for the first time iNKT cell adjuvant effects in pigs to SwIV Ags through augmenting the innate and adaptive immune responses in the respiratory tract. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Equilibrium dialysis-ligand exchange: adaptation of the method for determination of conditional stability constants of radionuclide-fulvic acid complexes

    International Nuclear Information System (INIS)

    Glaus, M.A.; Hummel, W.; Van Loon, L.R.

    1995-01-01

    The equilibrium dialysis-ligand exchange technique (EDLE) is used to determine conditional stability constants for the complexation of metal ions with humic acid, particularly in high pH solutions. Here, this technique has been adapted to measure conditional stability constants with fulvic acid. Fulvic acid permeates across all membranes during the experiment. The quantities involved therefore have to be determined analytically and taken into account when calculating the conditional stability constants. Co(II) and Laurentian Soil fulvic (LFA) acid were selected as a test system in order to investigate the time scale required to establish chemical and diffusion equilibria. After an incubation time of approximately two days, the conditional stability constants measured for the formation of Co-LFA-complexes are not time dependent, although across the whole time period investigated, LFA was still diffusing in increasing amounts across the dialysis membrane. This work demonstrates that the modified EDLE technique can be used in the determination of conditional metal stability constants of fulvic acid. (authors)

  8. Perceived Task-Difficulty Recognition from Log-File Information for the Use in Adaptive Intelligent Tutoring Systems

    Science.gov (United States)

    Janning, Ruth; Schatten, Carlotta; Schmidt-Thieme, Lars

    2016-01-01

    Recognising students' emotion, affect or cognition is a relatively young field and still a challenging task in the area of intelligent tutoring systems. There are several ways to use the output of these recognition tasks within the system. The approach most often mentioned in the literature is using it for giving feedback to the students. The…

  9. The IntFOLD server: an integrated web resource for protein fold recognition, 3D model quality assessment, intrinsic disorder prediction, domain prediction and ligand binding site prediction.

    Science.gov (United States)

    Roche, Daniel B; Buenavista, Maria T; Tetchner, Stuart J; McGuffin, Liam J

    2011-07-01

    The IntFOLD server is a novel independent server that integrates several cutting edge methods for the prediction of structure and function from sequence. Our guiding principles behind the server development were as follows: (i) to provide a simple unified resource that makes our prediction software accessible to all and (ii) to produce integrated output for predictions that can be easily interpreted. The output for predictions is presented as a simple table that summarizes all results graphically via plots and annotated 3D models. The raw machine readable data files for each set of predictions are also provided for developers, which comply with the Critical Assessment of Methods for Protein Structure Prediction (CASP) data standards. The server comprises an integrated suite of five novel methods: nFOLD4, for tertiary structure prediction; ModFOLD 3.0, for model quality assessment; DISOclust 2.0, for disorder prediction; DomFOLD 2.0 for domain prediction; and FunFOLD 1.0, for ligand binding site prediction. Predictions from the IntFOLD server were found to be competitive in several categories in the recent CASP9 experiment. The IntFOLD server is available at the following web site: http://www.reading.ac.uk/bioinf/IntFOLD/.

  10. A Self-Adaptive Dynamic Recognition Model for Fatigue Driving Based on Multi-Source Information and Two Levels of Fusion

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-09-01

    Full Text Available To improve the effectiveness and robustness of fatigue driving recognition, a self-adaptive dynamic recognition model is proposed that incorporates information from multiple sources and involves two sequential levels of fusion, constructed at the feature level and the decision level. Compared with existing models, the proposed model introduces a dynamic basic probability assignment (BPA to the decision-level fusion such that the weight of each feature source can change dynamically with the real-time fatigue feature measurements. Further, the proposed model can combine the fatigue state at the previous time step in the decision-level fusion to improve the robustness of the fatigue driving recognition. An improved correction strategy of the BPA is also proposed to accommodate the decision conflict caused by external disturbances. Results from field experiments demonstrate that the effectiveness and robustness of the proposed model are better than those of models based on a single fatigue feature and/or single-source information fusion, especially when the most effective fatigue features are used in the proposed model.

  11. Adaptation.

    Science.gov (United States)

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  12. Modular Adaptive System Based on a Multi-Stage Neural Structure for Recognition of 2D Objects of Discontinuous Production

    Directory of Open Access Journals (Sweden)

    I. Topalova

    2005-03-01

    Full Text Available This is a presentation of a new system for invariant recognition of 2D objects with overlapping classes, that can not be effectively recognized with the traditional methods. The translation, scale and partial rotation invariant contour object description is transformed in a DCT spectrum space. The obtained frequency spectrums are decomposed into frequency bands in order to feed different BPG neural nets (NNs. The NNs are structured in three stages - filtering and full rotation invariance; partial recognition; general classification. The designed multi-stage BPG Neural Structure shows very good accuracy and flexibility when tested with 2D objects used in the discontinuous production. The reached speed and the opportunuty for an easy restructuring and reprogramming of the system makes it suitable for application in different applied systems for real time work.

  13. Noise robust automatic speech recognition with adaptive quantile based noise estimation and speech band emphasizing filter bank

    DEFF Research Database (Denmark)

    Bonde, Casper Stork; Graversen, Carina; Gregersen, Andreas Gregers

    2005-01-01

    An important topic in Automatic Speech Recognition (ASR) is to reduce the effect of noise, in particular when mismatch exists between the training and application conditions. Many noise robutness schemes within the feature processing domain use as a prerequisite a noise estimate prior to the appe......An important topic in Automatic Speech Recognition (ASR) is to reduce the effect of noise, in particular when mismatch exists between the training and application conditions. Many noise robutness schemes within the feature processing domain use as a prerequisite a noise estimate prior....... Furthermore the paper investigates an alternative to the standard mel frequency cepstral coefficient filter bank (MFCC), an empirically chosen Speech Band Emphasizing filter bank (SBE), which improves the resolution in the speech band. The combinations of AQBNE and SBE are tested on the Danish SpeechDat-Car...

  14. Recognition tunneling

    International Nuclear Information System (INIS)

    Lindsay, Stuart; He Jin; Zhang Peiming; Chang Shuai; Huang Shuo; Sankey, Otto; Hapala, Prokop; Jelinek, Pavel

    2010-01-01

    Single molecules in a tunnel junction can now be interrogated reliably using chemically functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode ('tethered molecule-pair' configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the 'free-analyte' configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules. (topical review)

  15. Recognition tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, Stuart; He Jin; Zhang Peiming; Chang Shuai; Huang Shuo [Biodesign Institute, Arizona State University, Tempe, AZ 85287 (United States); Sankey, Otto [Department of Physics, Arizona State University, Tempe, AZ 85287 (United States); Hapala, Prokop; Jelinek, Pavel [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 1862 53, Prague (Czech Republic)

    2010-07-02

    Single molecules in a tunnel junction can now be interrogated reliably using chemically functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode ('tethered molecule-pair' configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the 'free-analyte' configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules. (topical review)

  16. Adaptation

    International Development Research Centre (IDRC) Digital Library (Canada)

    . Dar es Salaam. Durban. Bloemfontein. Antananarivo. Cape Town. Ifrane ... program strategy. A number of CCAA-supported projects have relevance to other important adaptation-related themes such as disaster preparedness and climate.

  17. Adaptation of the Neural Network Recognition System of the Helicopter on Its Acoustic Radiation to the Flight Speed

    Directory of Open Access Journals (Sweden)

    V. K. Hohlov

    2015-01-01

    Full Text Available The article concerns the adaptation of a neural tract that recognizes a helicopter from the aerodynamic and ground objects by its acoustic radiation to the helicopter flight speed. It uses non-centered informative signs-indications of estimating signal spectra, which correspond to the local extremes (maximums and minimums of the power spectrum of input signal and have the greatest information when differentiating the helicopter signals from those of tracked vehicles. The article gives justification to the principle of the neural network (NN adaptation and adaptation block structure, which solves problems of blade passage frequency estimation when capturing the object and track it when tracking a target, as well as forming a signal to control the resonant filter parameters of the selection block of informative signs. To create the discriminatory characteristics of the discriminator are used autoregressive statistical characteristics of the quadrature components of signal, obtained through the discrete Hilbert Converter (DGC that perforMathematical modeling of the tracking meter using the helicopter signals obtained in real conditions is performed. The article gives estimates of the tracking parameter when using a tracking meter with DGC by sequential records of realized acoustic noise of the helicopter. It also shows a block-diagram of the adaptive NN. The scientific novelty of the work is that providing the invariance of used informative sign, the counts of local extremes of power spectral density (PSD to changes in the helicopter flight speed is reached due to adding the NN structure and adaptation block, which is implemented as a meter to track the apparent passage frequency of the helicopter rotor blades using its relationship with a function of the autoregressive acoustic signal of the helicopter.Specialized literature proposes solutions based on the use of training classifiers with different parametric methods of spectral representations

  18. Noise robust automatic speech recognition with adaptive quantile based noise estimation and speech band emphasizing filter bank

    DEFF Research Database (Denmark)

    Bonde, Casper Stork; Graversen, Carina; Gregersen, Andreas Gregers

    2005-01-01

    to the appearance of the speech signal which require noise robust voice activity detection and assumptions of stationary noise. However, both of these requirements are often not met and it is therefore of particular interest to investigate methods like the Quantile Based Noise Estimation (QBNE) mehtod which...... estimates the noise during speech and non-speech sections without the use of a voice activity detector. While the standard QBNE-method uses a fixed pre-defined quantile accross all frequency bands, this paper suggests adaptive QBNE (AQBNE) which adapts the quantile individually to each frequency band...

  19. Adapt

    Science.gov (United States)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  20. State recognition of the viscoelastic sandwich structure based on the adaptive redundant second generation wavelet packet transform, permutation entropy and the wavelet support vector machine

    International Nuclear Information System (INIS)

    Qu, Jinxiu; Zhang, Zhousuo; Guo, Ting; Luo, Xue; Sun, Chuang; Li, Bing; Wen, Jinpeng

    2014-01-01

    The viscoelastic sandwich structure is widely used in mechanical equipment, yet the structure always suffers from damage during long-term service. Therefore, state recognition of the viscoelastic sandwich structure is very necessary for monitoring structural health states and keeping the equipment running with high reliability. Through the analysis of vibration response signals, this paper presents a novel method for this task based on the adaptive redundant second generation wavelet packet transform (ARSGWPT), permutation entropy (PE) and the wavelet support vector machine (WSVM). In order to tackle the non-linearity existing in the structure vibration response, the PE is introduced to reveal the state changes of the structure. In the case of complex non-stationary vibration response signals, in order to obtain more effective information regarding the structural health states, the ARSGWPT, which can adaptively match the characteristics of a given signal, is proposed to process the vibration response signals, and then multiple PE features are extracted from the resultant wavelet packet coefficients. The WSVM, which can benefit from the conventional SVM as well as wavelet theory, is applied to classify the various structural states automatically. In this study, to achieve accurate and automated state recognition, the ARSGWPT, PE and WSVM are combined for signal processing, feature extraction and state classification, respectively. To demonstrate the effectiveness of the proposed method, a typical viscoelastic sandwich structure is designed, and the different degrees of preload on the structure are used to characterize the various looseness states. The test results show that the proposed method can reliably recognize the different looseness states of the viscoelastic sandwich structure, and the WSVM can achieve a better classification performance than the conventional SVM. Moreover, the superiority of the proposed ARSGWPT in processing the complex vibration response

  1. Design of an Adaptive Human-Machine System Based on Dynamical Pattern Recognition of Cognitive Task-Load.

    Science.gov (United States)

    Zhang, Jianhua; Yin, Zhong; Wang, Rubin

    2017-01-01

    This paper developed a cognitive task-load (CTL) classification algorithm and allocation strategy to sustain the optimal operator CTL levels over time in safety-critical human-machine integrated systems. An adaptive human-machine system is designed based on a non-linear dynamic CTL classifier, which maps a set of electroencephalogram (EEG) and electrocardiogram (ECG) related features to a few CTL classes. The least-squares support vector machine (LSSVM) is used as dynamic pattern classifier. A series of electrophysiological and performance data acquisition experiments were performed on seven volunteer participants under a simulated process control task environment. The participant-specific dynamic LSSVM model is constructed to classify the instantaneous CTL into five classes at each time instant. The initial feature set, comprising 56 EEG and ECG related features, is reduced to a set of 12 salient features (including 11 EEG-related features) by using the locality preserving projection (LPP) technique. An overall correct classification rate of about 80% is achieved for the 5-class CTL classification problem. Then the predicted CTL is used to adaptively allocate the number of process control tasks between operator and computer-based controller. Simulation results showed that the overall performance of the human-machine system can be improved by using the adaptive automation strategy proposed.

  2. Adaptation

    International Development Research Centre (IDRC) Digital Library (Canada)

    Nairobi, Kenya. 28 Adapting Fishing Policy to Climate Change with the Aid of Scientific and Endogenous Knowledge. Cap Verde, Gambia,. Guinea, Guinea Bissau,. Mauritania and Senegal. Environment and Development in the Third World. (ENDA-TM). Dakar, Senegal. 29 Integrating Indigenous Knowledge in Climate Risk ...

  3. Design and use of conditional MHC class I ligands

    NARCIS (Netherlands)

    Toebes, Mireille; Coccoris, Miriam; Bins, Adriaan; Rodenko, Boris; Gomez, Raquel; Nieuwkoop, Nella J.; van de Kasteele, Willeke; Rimmelzwaan, Guus F.; Haanen, John B. A. G.; Ovaa, Huib; Schumacher, Ton N. M.

    2006-01-01

    Major histocompatibility complex (MHC) class I molecules associate with a variety of peptide ligands during biosynthesis and present these ligands on the cell surface for recognition by cytotoxic T cells. We have designed conditional MHC ligands that form stable complexes with MHC molecules but

  4. Adaptation of Candida albicans to environmental pH induces cell wall remodelling and enhances innate immune recognition.

    Directory of Open Access Journals (Sweden)

    Sarah L Sherrington

    2017-05-01

    Full Text Available Candida albicans is able to proliferate in environments that vary dramatically in ambient pH, a trait required for colonising niches such as the stomach, vaginal mucosal and the GI tract. Here we show that growth in acidic environments involves cell wall remodelling which results in enhanced chitin and β-glucan exposure at the cell wall periphery. Unmasking of the underlying immuno-stimulatory β-glucan in acidic environments enhanced innate immune recognition of C. albicans by macrophages and neutrophils, and induced a stronger proinflammatory cytokine response, driven through the C-type lectin-like receptor, Dectin-1. This enhanced inflammatory response resulted in significant recruitment of neutrophils in an intraperitoneal model of infection, a hallmark of symptomatic vaginal colonisation. Enhanced chitin exposure resulted from reduced expression of the cell wall chitinase Cht2, via a Bcr1-Rim101 dependent signalling cascade, while increased β-glucan exposure was regulated via a non-canonical signalling pathway. We propose that this "unmasking" of the cell wall may induce non-protective hyper activation of the immune system during growth in acidic niches, and may attribute to symptomatic vaginal infection.

  5. Endogenous ligands for C-type lectin receptors: the true regulators of immune homeostasis.

    Science.gov (United States)

    García-Vallejo, Juan J; van Kooyk, Yvette

    2009-07-01

    C-type lectin receptors (CLRs) have long been known as pattern-recognition receptors implicated in the recognition of pathogens by the innate immune system. However, evidence is accumulating that many CLRs are also able to recognize endogenous 'self' ligands and that this recognition event often plays an important role in immune homeostasis. In the present review, we focus on the human and mouse CLRs for which endogenous ligands have been described. Special attention is given to the signaling events initiated upon recognition of the self ligand and the regulation of glycosylation as a switch modulating CLR recognition, and therefore, immune homeostasis.

  6. Biomimetic affinity ligands for protein purification.

    Science.gov (United States)

    Sousa, Isabel T; Taipa, M Angela

    2014-01-01

    The development of sophisticated molecular modeling software and new bioinformatic tools, as well as the emergence of data banks containing detailed information about a huge number of proteins, enabled the de novo intelligent design of synthetic affinity ligands. Such synthetic compounds can be tailored to mimic natural biological recognition motifs or to interact with key surface-exposed residues on target proteins and are designated as "biomimetic ligands." A well-established methodology for generating biomimetic or synthetic affinity ligands integrates rational design with combinatorial solid-phase synthesis and screening, using the triazine scaffold and analogues of amino acids side chains to create molecular diversity.Triazine-based synthetic ligands are nontoxic, low-cost, highly stable compounds that can replace advantageously natural biological ligands in the purification of proteins by affinity-based methodologies.

  7. The pattern recognition molecule ficolin-1 exhibits differential binding to lymphocyte subsets, providing a novel link between innate and adaptive immunity

    DEFF Research Database (Denmark)

    Genster, Ninette; Ma, Ying Jie; Munthe-Fog, Lea

    2014-01-01

    and demonstrated that CD56(dim) NK-cells and both CD4(+) and CD8(+) subsets of activated T-cells were recognized by ficolin-1. In contrast we did not detect binding of ficolin-1 to CD56(bright) NK-cells, NKT-cells, resting T-cells or B-cells. Furthermore, we showed that the protein-lymphocyte interaction occurred......Ficolin-1 is a soluble pattern recognition molecule synthesized by myeloid cells and capable of activating the lectin pathway of complement on the surface of pathogens. It is tethered to the membranes of monocytes and granulocytes; however, the biological significance of cell-associated ficolin-1...... is unknown. Recognition of healthy host cells by a pattern recognition molecule constitutes a potential hazard to self cells and tissues, emphasizing the importance of further elucidating the reported self-recognition. In the current study we investigated the potential recognition of lymphocytes by ficolin-1...

  8. Pattern recognition

    CERN Document Server

    Theodoridis, Sergios

    2003-01-01

    Pattern recognition is a scientific discipline that is becoming increasingly important in the age of automation and information handling and retrieval. Patter Recognition, 2e covers the entire spectrum of pattern recognition applications, from image analysis to speech recognition and communications. This book presents cutting-edge material on neural networks, - a set of linked microprocessors that can form associations and uses pattern recognition to ""learn"" -and enhances student motivation by approaching pattern recognition from the designer's point of view. A direct result of more than 10

  9. Ligand-Mediated Coating of Liposomes with Human Serum Albumin.

    Science.gov (United States)

    Sato, Hikari; Nakhaei, Elnaz; Kawano, Takahito; Murata, Masaharu; Kishimura, Akihiro; Mori, Takeshi; Katayama, Yoshiki

    2018-02-13

    Coating liposome surfaces with human serum albumin (HSA) can improve the colloidal stability and prevent opsonization. HSA coating via specific binding with alkyl ligands is promising because although the ligand-mediated coating is relatively stable it can spontaneously exchange with fresh HSA. However, to achieve surface coating with HSA, multiple hydrophobic ligands must be exposed to an aqueous medium prior to binding with HSA. This presents a challenge, as hydrophobic ligands tend to be buried in the liposomal membrane. Here we present the first HSA modification of liposome surfaces via alkyl ligands. We found that a relatively short alkyl ligand, or a long alkyl ligand with a terminal carboxylate, could be exposed on the liposome surface without causing aggregation of the liposomes and these ligands could subsequently bind HSA. The resulting HSA-coated liposomes were as inert as conventional PEGylated liposomes in terms of macrophage recognition.

  10. A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavity

    Energy Technology Data Exchange (ETDEWEB)

    Breustedt, Daniel A.; Chatwell, Lorenz; Skerra, Arne, E-mail: skerra@wzw.tum.de [Munich Center for Integrated Protein Science, CIPS-M, and Lehrstuhl für Biologische Chemie, Technische Universität München, 85350 Freising-Weihenstephan (Germany)

    2009-10-01

    The crystal structure of tear lipocalin determined in space group P2{sub 1} revealed large structural deviations from the previously solved X-ray structure in space group C2, especially in the loop region and adjoining parts of the β-barrel which give rise to the ligand-binding site. These findings illustrate a novel mechanism for promiscuity in ligand recognition by the lipocalin protein family. Tear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P2{sub 1} with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6 Å resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P2{sub 1} crystal form uncovered major conformational changes (i) in β-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the β-barrel and (iii) in the extended C-terminal segment, which is attached to the β-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family.

  11. A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavity

    International Nuclear Information System (INIS)

    Breustedt, Daniel A.; Chatwell, Lorenz; Skerra, Arne

    2009-01-01

    The crystal structure of tear lipocalin determined in space group P2 1 revealed large structural deviations from the previously solved X-ray structure in space group C2, especially in the loop region and adjoining parts of the β-barrel which give rise to the ligand-binding site. These findings illustrate a novel mechanism for promiscuity in ligand recognition by the lipocalin protein family. Tear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P2 1 with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6 Å resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P2 1 crystal form uncovered major conformational changes (i) in β-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the β-barrel and (iii) in the extended C-terminal segment, which is attached to the β-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family

  12. The PDZ domain as a complex adaptive system.

    Directory of Open Access Journals (Sweden)

    Alexei Kurakin

    2007-09-01

    Full Text Available Specific protein associations define the wiring of protein interaction networks and thus control the organization and functioning of the cell as a whole. Peptide recognition by PDZ and other protein interaction domains represents one of the best-studied classes of specific protein associations. However, a mechanistic understanding of the relationship between selectivity and promiscuity commonly observed in the interactions mediated by peptide recognition modules as well as its functional meaning remain elusive. To address these questions in a comprehensive manner, two large populations of artificial and natural peptide ligands of six archetypal PDZ domains from the synaptic proteins PSD95 and SAP97 were generated by target-assisted iterative screening (TAIS of combinatorial peptide libraries and by synthesis of proteomic fragments, correspondingly. A comparative statistical analysis of affinity-ranked artificial and natural ligands yielded a comprehensive picture of known and novel PDZ ligand specificity determinants, revealing a hitherto unappreciated combination of specificity and adaptive plasticity inherent to PDZ domain recognition. We propose a reconceptualization of the PDZ domain in terms of a complex adaptive system representing a flexible compromise between the rigid order of exquisite specificity and the chaos of unselective promiscuity, which has evolved to mediate two mutually contradictory properties required of such higher order sub-cellular organizations as synapses, cell junctions, and others--organizational structure and organizational plasticity/adaptability. The generalization of this reconceptualization in regard to other protein interaction modules and specific protein associations is consistent with the image of the cell as a complex adaptive macromolecular system as opposed to clockwork.

  13. Speech Recognition

    Directory of Open Access Journals (Sweden)

    Adrian Morariu

    2009-01-01

    Full Text Available This paper presents a method of speech recognition by pattern recognition techniques. Learning consists in determining the unique characteristics of a word (cepstral coefficients by eliminating those characteristics that are different from one word to another. For learning and recognition, the system will build a dictionary of words by determining the characteristics of each word to be used in the recognition. Determining the characteristics of an audio signal consists in the following steps: noise removal, sampling it, applying Hamming window, switching to frequency domain through Fourier transform, calculating the magnitude spectrum, filtering data, determining cepstral coefficients.

  14. Pattern recognition in speech and language processing

    CERN Document Server

    Chou, Wu

    2003-01-01

    Minimum Classification Error (MSE) Approach in Pattern Recognition, Wu ChouMinimum Bayes-Risk Methods in Automatic Speech Recognition, Vaibhava Goel and William ByrneA Decision Theoretic Formulation for Adaptive and Robust Automatic Speech Recognition, Qiang HuoSpeech Pattern Recognition Using Neural Networks, Shigeru KatagiriLarge Vocabulary Speech Recognition Based on Statistical Methods, Jean-Luc GauvainToward Spontaneous Speech Recognition and Understanding, Sadaoki FuruiSpeaker Authentication, Qi Li and Biing-Hwang JuangHMMs for Language Processing Problems, Ri

  15. Slow molecular recognition by RNA.

    Science.gov (United States)

    Gleitsman, Kristin R; Sengupta, Raghuvir N; Herschlag, Daniel

    2017-12-01

    Molecular recognition is central to biological processes, function, and specificity. Proteins associate with ligands with a wide range of association rate constants, with maximal values matching the theoretical limit set by the rate of diffusional collision. As less is known about RNA association, we compiled association rate constants for all RNA/ligand complexes that we could find in the literature. Like proteins, RNAs exhibit a wide range of association rate constants. However, the fastest RNA association rates are considerably slower than those of the fastest protein associations and fall well below the diffusional limit. The apparently general observation of slow association with RNAs has implications for evolution and for modern-day biology. Our compilation highlights a quantitative molecular property that can contribute to biological understanding and underscores our need to develop a deeper physical understanding of molecular recognition events. © 2017 Gleitsman et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  16. Identification of small heat shock protein B8 (HSP22) as a novel TLR4 ligand and potential involvement in the pathogenesis of rheumatoid arthritis.

    NARCIS (Netherlands)

    Roelofs, M.F.; Boelens, W.C.; Joosten, L.A.B.; Abdollahi-Roodsaz, S.; Geurts, J.; Wunderink, L.U.; Schreurs, B.W.; Berg, W.B. van den; Radstake, T.R.D.J.

    2006-01-01

    Dendritic cells (DCs) are specialized APCs that can be activated upon pathogen recognition as well as recognition of endogenous ligands, which are released during inflammation and cell stress. The recognition of exogenous and endogenous ligands depends on TLRs, which are abundantly expressed in

  17. Ligands in PSI structures

    International Nuclear Information System (INIS)

    Kumar, Abhinav; Chiu, Hsiu-Ju; Axelrod, Herbert L.; Morse, Andrew; Elsliger, Marc-André; Wilson, Ian A.; Deacon, Ashley

    2010-01-01

    A survey of the types and frequency of ligands that are bound to PSI structures is analyzed as well as their utility in functional annotation of previously uncharacterized proteins. Approximately 65% of PSI structures report some type of ligand(s) that is bound in the crystal structure. Here, a description is given of how such ligands are handled and analyzed at the JCSG and a survey of the types, variety and frequency of ligands that are observed in the PSI structures is also compiled and analyzed, including illustrations of how these bound ligands have provided functional clues for annotation of proteins with little or no previous experimental characterization. Furthermore, a web server was developed as a tool to mine and analyze the PSI structures for bound ligands and other identifying features

  18. THERMODYNAMICS OF PROTEIN-LIGAND INTERACTIONS AND THEIR ANALYSIS

    Directory of Open Access Journals (Sweden)

    Rummi Devi Saini

    2017-11-01

    Full Text Available Physiological processes are controlled mainly by intermolecular recognition mechanisms which involve protein–protein and protein–ligand interactions with a high specificity and affinity to form a specific complex. Proteins being an important class of macromolecules in biological systems, it is important to understand their actions through binding to other molecules of proteins or ligands. In fact, the binding of low molecular weight ligands to proteins plays a significant role in regulating biological processes such as cellular metabolism and signal transmission. Therefore knowledge of the protein–ligand interactions and the knowledge of the mechanisms involved in the protein-ligand recognition and binding are key in understanding biology at molecular level which will facilitate the discovery, design, and development of drugs. In this review, the mechanisms involved in protein–ligand binding, the binding kinetics, thermodynamic concepts and binding driving forces are discussed. Thermodynamic mechanisms involved in a few important protein-ligand binding are described. Various spectroscopic, non-spectroscopic and computational method for analysis of protein–ligand binding are also discussed.

  19. Characteristic molecular vibrations of adenosine receptor ligands.

    Science.gov (United States)

    Chee, Hyun Keun; Yang, Jin-San; Joung, Je-Gun; Zhang, Byoung-Tak; Oh, S June

    2015-02-13

    Although the regulation of membrane receptor activation is known to be crucial for molecular signal transduction, the molecular mechanism underlying receptor activation is not fully elucidated. Here we study the physicochemical nature of membrane receptor behavior by investigating the characteristic molecular vibrations of receptor ligands using computational chemistry and informatics methods. By using information gain, t-tests, and support vector machines, we have identified highly informative features of adenosine receptor (AdoR) ligand and corresponding functional amino acid residues such as Asn (6.55) of AdoR that has informative significance and is indispensable for ligand recognition of AdoRs. These findings may provide new perspectives and insights into the fundamental mechanism of class A G protein-coupled receptor activation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  20. Speaker Recognition

    DEFF Research Database (Denmark)

    Mølgaard, Lasse Lohilahti; Jørgensen, Kasper Winther

    2005-01-01

    Speaker recognition is basically divided into speaker identification and speaker verification. Verification is the task of automatically determining if a person really is the person he or she claims to be. This technology can be used as a biometric feature for verifying the identity of a person...

  1. A Bayesian classifier for symbol recognition

    OpenAIRE

    Barrat , Sabine; Tabbone , Salvatore; Nourrissier , Patrick

    2007-01-01

    URL : http://www.buyans.com/POL/UploadedFile/134_9977.pdf; International audience; We present in this paper an original adaptation of Bayesian networks to symbol recognition problem. More precisely, a descriptor combination method, which enables to improve significantly the recognition rate compared to the recognition rates obtained by each descriptor, is presented. In this perspective, we use a simple Bayesian classifier, called naive Bayes. In fact, probabilistic graphical models, more spec...

  2. Quantum.Ligand.Dock: protein-ligand docking with quantum entanglement refinement on a GPU system.

    Science.gov (United States)

    Kantardjiev, Alexander A

    2012-07-01

    Quantum.Ligand.Dock (protein-ligand docking with graphic processing unit (GPU) quantum entanglement refinement on a GPU system) is an original modern method for in silico prediction of protein-ligand interactions via high-performance docking code. The main flavour of our approach is a combination of fast search with a special account for overlooked physical interactions. On the one hand, we take care of self-consistency and proton equilibria mutual effects of docking partners. On the other hand, Quantum.Ligand.Dock is the the only docking server offering such a subtle supplement to protein docking algorithms as quantum entanglement contributions. The motivation for development and proposition of the method to the community hinges upon two arguments-the fundamental importance of quantum entanglement contribution in molecular interaction and the realistic possibility to implement it by the availability of supercomputing power. The implementation of sophisticated quantum methods is made possible by parallelization at several bottlenecks on a GPU supercomputer. The high-performance implementation will be of use for large-scale virtual screening projects, structural bioinformatics, systems biology and fundamental research in understanding protein-ligand recognition. The design of the interface is focused on feasibility and ease of use. Protein and ligand molecule structures are supposed to be submitted as atomic coordinate files in PDB format. A customization section is offered for addition of user-specified charges, extra ionogenic groups with intrinsic pK(a) values or fixed ions. Final predicted complexes are ranked according to obtained scores and provided in PDB format as well as interactive visualization in a molecular viewer. Quantum.Ligand.Dock server can be accessed at http://87.116.85.141/LigandDock.html.

  3. Quantum.Ligand.Dock: protein–ligand docking with quantum entanglement refinement on a GPU system

    Science.gov (United States)

    Kantardjiev, Alexander A.

    2012-01-01

    Quantum.Ligand.Dock (protein–ligand docking with graphic processing unit (GPU) quantum entanglement refinement on a GPU system) is an original modern method for in silico prediction of protein–ligand interactions via high-performance docking code. The main flavour of our approach is a combination of fast search with a special account for overlooked physical interactions. On the one hand, we take care of self-consistency and proton equilibria mutual effects of docking partners. On the other hand, Quantum.Ligand.Dock is the the only docking server offering such a subtle supplement to protein docking algorithms as quantum entanglement contributions. The motivation for development and proposition of the method to the community hinges upon two arguments—the fundamental importance of quantum entanglement contribution in molecular interaction and the realistic possibility to implement it by the availability of supercomputing power. The implementation of sophisticated quantum methods is made possible by parallelization at several bottlenecks on a GPU supercomputer. The high-performance implementation will be of use for large-scale virtual screening projects, structural bioinformatics, systems biology and fundamental research in understanding protein–ligand recognition. The design of the interface is focused on feasibility and ease of use. Protein and ligand molecule structures are supposed to be submitted as atomic coordinate files in PDB format. A customization section is offered for addition of user-specified charges, extra ionogenic groups with intrinsic pKa values or fixed ions. Final predicted complexes are ranked according to obtained scores and provided in PDB format as well as interactive visualization in a molecular viewer. Quantum.Ligand.Dock server can be accessed at http://87.116.85.141/LigandDock.html. PMID:22669908

  4. DNA-based adaptive immunity protect host from infection-associated periodontal bone resorption via recognition of Porphyromonas gingivalis virulence component.

    Science.gov (United States)

    Han, Xiaozhe; LaRosa, Karen B; Kawai, Toshihisa; Taubman, Martin A

    2014-01-03

    Porphyromonas gingivalis (Pg) is one of a constellation of oral organisms associated with human chronic periodontitis. While adaptive immunity to periodontal pathogen proteins has been investigated and is an important component of periodontal bone resorption, the effect of periodontal pathogen DNA in eliciting systemic and mucosal antibody and modulating immune responses has not been investigated. Rowett rats were locally injected with whole genomic Pg DNA in alum. Escherichia coli (Ec) genomic DNA, Fusobacterium nucleatum (Fn) genomic DNA, and saline/alum injected rats served as controls. After various time points, serum IgG and salivary IgA antibody to Ec, Fn or Pg were detected by ELISA. Serum and salivary antibody reactions with Pg surface antigens were determined by Western blot analyses and the specific antigen was identified by mass spectrometry. Effects of genomic DNA immunization on Pg bacterial colonization and experimental periodontal bone resorption were also evaluated. Sera from Pg DNA, Ec DNA and Fn DNA-injected rats did not react with Ec or Fn bacteria. Serum IgG antibody levels to Pg and Pg surface extracts were significantly higher in animals immunized with Pg DNA as compared to the control groups. Rats injected with Pg DNA demonstrated a strong serum IgG and salivary IgA antibody reaction solely to Pg fimbrillin (41kDa), the major protein component of Pg fimbriae. In the Pg DNA-immunized group, the numbers of Pg bacteria in oral cavity and the extent of periodontal bone resorption were significantly reduced after Pg infection. This study suggests that infected hosts may select specific genes from whole genomic DNA of the periodontal pathogen for transcription and presentation. The results indicate that the unique gene selected can initiate a host protective immune response to the parent bacterium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Flexible Piezoelectric Sensor-Based Gait Recognition

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2018-02-01

    Full Text Available Most motion recognition research has required tight-fitting suits for precise sensing. However, tight-suit systems have difficulty adapting to real applications, because people normally wear loose clothes. In this paper, we propose a gait recognition system with flexible piezoelectric sensors in loose clothing. The gait recognition system does not directly sense lower-body angles. It does, however, detect the transition between standing and walking. Specifically, we use the signals from the flexible sensors attached to the knee and hip parts on loose pants. We detect the periodic motion component using the discrete time Fourier series from the signal during walking. We adapt the gait detection method to a real-time patient motion and posture monitoring system. In the monitoring system, the gait recognition operates well. Finally, we test the gait recognition system with 10 subjects, for which the proposed system successfully detects walking with a success rate over 93 %.

  6. C-type lectins: their network and roles in pathogen recognition and immunity.

    Science.gov (United States)

    Mayer, Sabine; Raulf, Marie-Kristin; Lepenies, Bernd

    2017-02-01

    C-type lectins (CTLs) represent the most complex family of animal/human lectins that comprises 17 different groups. During evolution, CTLs have developed by diversification to cover a broad range of glycan ligands. However, ligand binding by CTLs is not necessarily restricted to glycans as some CTLs also bind to proteins, lipids, inorganic molecules, or ice crystals. CTLs share a common fold that harbors a Ca 2+ for contact to the sugar and about 18 invariant residues in a phylogenetically conserved pattern. In vertebrates, CTLs have numerous functions, including serum glycoprotein homeostasis, pathogen sensing, and the initiation of immune responses. Myeloid CTLs in innate immunity are mainly expressed by antigen-presenting cells and play a prominent role in the recognition of a variety of pathogens such as fungi, bacteria, viruses, and parasites. However, myeloid CTLs such as the macrophage inducible CTL (Mincle) or Clec-9a may also bind to self-antigens and thus contribute to immune homeostasis. While some CTLs induce pro-inflammatory responses and thereby lead to activation of adaptive immune responses, other CTLs act as inhibitory receptors and dampen cellular functions. Since CTLs are key players in pathogen recognition and innate immunity, targeting CTLs may be a promising strategy for cell-specific delivery of drugs or vaccine antigens and to modulate immune responses.

  7. Indirect recognition

    DEFF Research Database (Denmark)

    Lund, Christian; Rachman, Noer Fauzi

    2018-01-01

    Government institutions and local people in Indonesia have entrenched, resurrected, and reinvented space through their different territorial and property claims. From colonial times, onward, government institutions have dissolved local political orders and territorialized and reordered spatial...... categories are struggled over, and groups of actors seek to legitimate their presence, their activities, and their resource use by occupation, mapping, and construction of "public" infrastructure. In the case of conservation in the Mount Halimun-Salak National Park, we find that rather than one overarching...... important legal and political work. After the authoritarian New Order regime, in particular, claims to citizenship worked as indirect property claims, and indirect recognition of such claims are important because they serve as pragmatic proxies for formal property rights. Two case studies examine how people...

  8. Physics of Automatic Target Recognition

    CERN Document Server

    Sadjadi, Firooz

    2007-01-01

    Physics of Automatic Target Recognition addresses the fundamental physical bases of sensing, and information extraction in the state-of-the art automatic target recognition field. It explores both passive and active multispectral sensing, polarimetric diversity, complex signature exploitation, sensor and processing adaptation, transformation of electromagnetic and acoustic waves in their interactions with targets, background clutter, transmission media, and sensing elements. The general inverse scattering, and advanced signal processing techniques and scientific evaluation methodologies being used in this multi disciplinary field will be part of this exposition. The issues of modeling of target signatures in various spectral modalities, LADAR, IR, SAR, high resolution radar, acoustic, seismic, visible, hyperspectral, in diverse geometric aspects will be addressed. The methods for signal processing and classification will cover concepts such as sensor adaptive and artificial neural networks, time reversal filt...

  9. Structural Basis of Cooperative Ligand Binding by the Glycine Riboswitch

    Energy Technology Data Exchange (ETDEWEB)

    E Butler; J Wang; Y Xiong; S Strobel

    2011-12-31

    The glycine riboswitch regulates gene expression through the cooperative recognition of its amino acid ligand by a tandem pair of aptamers. A 3.6 {angstrom} crystal structure of the tandem riboswitch from the glycine permease operon of Fusobacterium nucleatum reveals the glycine binding sites and an extensive network of interactions, largely mediated by asymmetric A-minor contacts, that serve to communicate ligand binding status between the aptamers. These interactions provide a structural basis for how the glycine riboswitch cooperatively regulates gene expression.

  10. Sterically demanding iminopyridine ligands

    NARCIS (Netherlands)

    Irrgang, Torsten; Keller, Sandra; Maisel, Heidi; Kretschmer, Winfried; Kempe, Rhett

    Two sterically demanding iminopyridine ligands, (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridin-2-ylmeth- ylene]amine and (2,6-diisopropylphenyl)]6-(2,6-dimethylphenyl)pyridin-2-ylmethylene]amine, were prepared by a two-step process: first, condensation of 6-bromopyridine-2-carbaldehyde

  11. Aptamer-based molecular recognition for biosensor development.

    Science.gov (United States)

    Zhou, Jing; Battig, Mark R; Wang, Yong

    2010-11-01

    Nucleic acid aptamers are an emerging class of synthetic ligands and have recently attracted significant attention in numerous fields. One is in biosensor development. In principle, nucleic acid aptamers can be discovered to recognize any molecule of interest with high affinity and specificity. In addition, unlike most ligands evolved in nature, synthetic nucleic acid aptamers are usually tolerant of harsh chemical, physical, and biological conditions. These distinguished characteristics make aptamers attractive molecular recognition ligands for biosensing applications. This review first concisely introduces methods for aptamer discovery including upstream selection and downstream truncation, then discusses aptamer-based biosensor development from the viewpoint of signal production.

  12. On the hunt for helminths: innate immune cells in the recognition and response to helminth parasites.

    Science.gov (United States)

    Perrigoue, Jacqueline G; Marshall, Fraser A; Artis, David

    2008-09-01

    The generation of protective immunity to helminth parasites is critically dependent upon the development of a CD4(+) T helper type 2 cytokine response. However, the host-parasite interactions responsible for initiating this response are poorly understood. This review will discuss recent advances in our understanding of how helminth-derived products are recognized by innate immune cells. Specifically, interactions between helminth excretory/secretory products and host Toll-like receptors and lectins will be discussed as well as the putative functions of helminth proteases and chitin in activating and recruiting innate immune cells. In addition, the functional significance of pattern recognition by epithelial cells, granulocytes, dendritic cells and macrophages including expression of alarmins, thymic stromal lymphopoetin, interleukin (IL)-25, IL-33 and Notch ligands in the development of adaptive anti-parasite Th2 cytokine responses will be examined.

  13. Starch Catabolism by a Prominent Human Gut Symbiont Is Directed by the Recognition of Amylose Helices

    Energy Technology Data Exchange (ETDEWEB)

    Koropatkin, Nicole M.; Martens, Eric C.; Gordon, Jeffrey I.; Smith, Thomas J. (WU); (Danforth)

    2009-01-12

    The human gut microbiota performs functions that are not encoded in our Homo sapiens genome, including the processing of otherwise undigestible dietary polysaccharides. Defining the structures of proteins involved in the import and degradation of specific glycans by saccharolytic bacteria complements genomic analysis of the nutrient-processing capabilities of gut communities. Here, we describe the atomic structure of one such protein, SusD, required for starch binding and utilization by Bacteroides thetaiotaomicron, a prominent adaptive forager of glycans in the distal human gut microbiota. The binding pocket of this unique {alpha}-helical protein contains an arc of aromatic residues that complements the natural helical structure of starch and imposes this conformation on bound maltoheptaose. Furthermore, SusD binds cyclic oligosaccharides with higher affinity than linear forms. The structures of several SusD/oligosaccharide complexes reveal an inherent ligand recognition plasticity dominated by the three-dimensional conformation of the oligosaccharides rather than specific interactions with the composite sugars.

  14. Learning and Domain Adaptation

    Science.gov (United States)

    Mansour, Yishay

    Domain adaptation is a fundamental learning problem where one wishes to use labeled data from one or several source domains to learn a hypothesis performing well on a different, yet related, domain for which no labeled data is available. This generalization across domains is a very significant challenge for many machine learning applications and arises in a variety of natural settings, including NLP tasks (document classification, sentiment analysis, etc.), speech recognition (speakers and noise or environment adaptation) and face recognition (different lighting conditions, different population composition).

  15. Adaptive Morse code communication system for severely disabled individuals.

    Science.gov (United States)

    Yang, C H

    2000-01-01

    Morse code with an easy-to-operate, single switch input system has been shown to be an excellent communication adaptive device. Because maintaining a stable typing rate is not easy for the disabled, the automatic recognition of Morse code is difficult. Therefore, a suitable adaptive automatic recognition method is needed. This paper presents the application of a Least-Mean-Square algorithm to adaptive Morse code recognition for persons with impaired hand coordination and dexterity. Four processes are involved in this adaptive Morse code recognition method: space recognition, tone recognition, adaptive processing, and character recognition. Statistical analyses demonstrated that the proposed method results in a better recognition rate for the participants tested in comparison to other methods from the literature.

  16. Analysis of macromolecules, ligands and macromolecule-ligand complexes

    Science.gov (United States)

    Von Dreele, Robert B [Los Alamos, NM

    2008-12-23

    A method for determining atomic level structures of macromolecule-ligand complexes through high-resolution powder diffraction analysis and a method for providing suitable microcrystalline powder for diffraction analysis are provided. In one embodiment, powder diffraction data is collected from samples of polycrystalline macromolecule and macromolecule-ligand complex and the refined structure of the macromolecule is used as an approximate model for a combined Rietveld and stereochemical restraint refinement of the macromolecule-ligand complex. A difference Fourier map is calculated and the ligand position and points of interaction between the atoms of the macromolecule and the atoms of the ligand can be deduced and visualized. A suitable polycrystalline sample of macromolecule-ligand complex can be produced by physically agitating a mixture of lyophilized macromolecule, ligand and a solvent.

  17. Radiobiology with DNA ligands

    International Nuclear Information System (INIS)

    Weinreich, R.; Argentini, M.; Guenther, I.; Koziorowski, J.; Larsson, B.; Nievergelt-Egido, M.C.; Salt, C.; Wyer, L.; Dos Santos, D.F.; Hansen, H.J.

    1997-01-01

    The paper deals with the following topics: labelling of DNA ligands and other tumour-affinic compounds with 4.15-d 124 I, radiotoxicity of Hoechst 33258 and 33342 and of iodinated Hoechst 33258 in cell cultures, preparation of 76 Br-, 123 I-, and 221 At-labelled 5-halo-2'-deoxyuridine, chemical syntheses of boron derivatives of Hoechst 33258.III., Gadolinium neutron capture therapy

  18. Therapeutic androgen receptor ligands

    Science.gov (United States)

    Allan, George F.; Sui, Zhihua

    2003-01-01

    In the past several years, the concept of tissue-selective nuclear receptor ligands has emerged. This concept has come to fruition with estrogens, with the successful marketing of drugs such as raloxifene. The discovery of raloxifene and other selective estrogen receptor modulators (SERMs) has raised the possibility of generating selective compounds for other pathways, including androgens (that is, selective androgen receptor modulators, or SARMs). PMID:16604181

  19. Regulation mechanisms of the FLT3-ligand after irradiation

    International Nuclear Information System (INIS)

    Prat-Lepesant, M.

    2005-06-01

    The hematopoietic compartment is one of the most severely damaged after chemotherapy, radiotherapy or accidental irradiations. Whatever its origin, the resulting damage to the bone marrow remains difficult to evaluate. Thus, it would be of great interest to get a biological indicator of residual hematopoiesis in order to adapt the treatment to each clinical situation. Recent results indicated that the plasma Flt3 ligand concentration was increased in patients suffering from either acquired or induced aplasia, suggesting that Flt3 ligand might be useful as a biological indicator of bone marrow status. We thus followed in a mouse model as well as in several clinical situations the variations in plasma Flt3 ligand concentration, after either homogeneous or heterogeneous irradiations. These variations were correlated to the number of hematopoietic progenitors and to other parameters such as duration and depth of pancytopenia. The results indicated that the concentration of Flt3 ligand in the blood reflects the bone marrow status, and that the follow-up of plasma Flt3 ligand concentration could give predictive information about the bone marrow function and the duration and severity of pancytopenia and thrombocytopenia. Nevertheless, the clinical use of Flt3 ligand as a biological indicator of bone marrow damage require the knowledge of the mechanisms regulating the variations in plasma Flt3 ligand concentration. We thus developed a study in the mouse model. The results indicated that the variations in plasma Flt3 ligand variations were not solely due to a balance between its production by lymphoid cells and its consumption by hematopoietic cells. Moreover, we showed that T lymphocytes are not the main regulator of plasma Flt3 ligand concentration as previously suggested, and that other cell types, possibly including bone marrow stromal cells, might be strongly implicated. These results also suggest that the Flt3 ligand is a main systemic regulator of hematopoiesis

  20. Ficolins and FIBCD1: Soluble and membrane bound pattern recognition molecules with acetyl group selectivity

    DEFF Research Database (Denmark)

    Thomsen, Theresa; Schlosser, Anders; Holmskov, Uffe

    2011-01-01

    as pattern recognition molecules. Ficolins are soluble oligomeric proteins composed of trimeric collagen-like regions linked to fibrinogen-related domains (FReDs) that have the ability to sense molecular patterns on both pathogens and apoptotic cell surfaces and activate the complement system. The ficolins......D-containing molecules, and discusses structural resemblance but also diversity in recognition of acetylated ligands....

  1. Analytical developments for screening of lanthanides/ligands interactions

    International Nuclear Information System (INIS)

    Varenne, F.

    2012-01-01

    This work investigates the potential of hyphenated capillary electrophoresis and inductively coupled mass spectrometry to classify different ligands according to their europium binding affinity in a hydro-organic medium. On the one hand, this method enables to evaluate the affinity of phosphorus-containing ligands in less than two hours and using less than 15 ng of ligand. On the other hand, complexation constants could be determined. The results are in excellent agreement with the values obtained by spectrophotometric titrations.Moreover, a library of copolymers for solid/liquid extraction of europium is investigated. The extraction protocol enables to classify copolymers according to their europium affinity in a hydro-organic medium. This screening requires 60 mg of copolymers. For the most promising recognition properties and selectivity La 3+ /Eu 3+ /Lu 3+ are evaluated. (author)

  2. Regulation mechanisms of the FLT3-ligand after irradiation; Mecanismes de regulation du FLT3-ligand apres irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Prat-Lepesant, M

    2005-06-15

    The hematopoietic compartment is one of the most severely damaged after chemotherapy, radiotherapy or accidental irradiations. Whatever its origin, the resulting damage to the bone marrow remains difficult to evaluate. Thus, it would be of great interest to get a biological indicator of residual hematopoiesis in order to adapt the treatment to each clinical situation. Recent results indicated that the plasma Flt3 ligand concentration was increased in patients suffering from either acquired or induced aplasia, suggesting that Flt3 ligand might be useful as a biological indicator of bone marrow status. We thus followed in a mouse model as well as in several clinical situations the variations in plasma Flt3 ligand concentration, after either homogeneous or heterogeneous irradiations. These variations were correlated to the number of hematopoietic progenitors and to other parameters such as duration and depth of pancytopenia. The results indicated that the concentration of Flt3 ligand in the blood reflects the bone marrow status, and that the follow-up of plasma Flt3 ligand concentration could give predictive information about the bone marrow function and the duration and severity of pancytopenia and thrombocytopenia. Nevertheless, the clinical use of Flt3 ligand as a biological indicator of bone marrow damage require the knowledge of the mechanisms regulating the variations in plasma Flt3 ligand concentration. We thus developed a study in the mouse model. The results indicated that the variations in plasma Flt3 ligand variations were not solely due to a balance between its production by lymphoid cells and its consumption by hematopoietic cells. Moreover, we showed that T lymphocytes are not the main regulator of plasma Flt3 ligand concentration as previously suggested, and that other cell types, possibly including bone marrow stromal cells, might be strongly implicated. These results also suggest that the Flt3 ligand is a main systemic regulator of hematopoiesis

  3. Use of the recognition heuristic depends on the domain's recognition validity, not on the recognition validity of selected sets of objects.

    Science.gov (United States)

    Pohl, Rüdiger F; Michalkiewicz, Martha; Erdfelder, Edgar; Hilbig, Benjamin E

    2017-07-01

    According to the recognition-heuristic theory, decision makers solve paired comparisons in which one object is recognized and the other not by recognition alone, inferring that recognized objects have higher criterion values than unrecognized ones. However, success-and thus usefulness-of this heuristic depends on the validity of recognition as a cue, and adaptive decision making, in turn, requires that decision makers are sensitive to it. To this end, decision makers could base their evaluation of the recognition validity either on the selected set of objects (the set's recognition validity), or on the underlying domain from which the objects were drawn (the domain's recognition validity). In two experiments, we manipulated the recognition validity both in the selected set of objects and between domains from which the sets were drawn. The results clearly show that use of the recognition heuristic depends on the domain's recognition validity, not on the set's recognition validity. In other words, participants treat all sets as roughly representative of the underlying domain and adjust their decision strategy adaptively (only) with respect to the more general environment rather than the specific items they are faced with.

  4. Production of the soluble human Fas ligand by Dictyostelium discoideum cultivated on a synthetic medium

    NARCIS (Netherlands)

    Lu, Y.H.; Knol, J.C.; Linskens, M.H.K.; Friehs, K.; van Haastert, P. J. M.; Flaschel, E.

    2004-01-01

    Human Fas ligand (hFasL) is of considerable interest since it is a type II transmembrane glycoprotein that induces programmed cell death, or apoptosis. In this study Dictyostelium discoideum was used to produce a soluble form of the human Fas ligand. The recombinant cells were adapted to a modified

  5. Thermodynamic fingerprints of ligand binding to human telomeric G-quadruplexes

    OpenAIRE

    Bon?ina, Matja?; Podlipnik, ?rtomir; Piantanida, Ivo; Eilmes, Julita; Teulade-Fichou, Marie-Paule; Vesnaver, Gorazd; Lah, Jurij

    2015-01-01

    Thermodynamic studies of ligand binding to human telomere (ht) DNA quadruplexes, as a rule, neglect the involvement of various ht-DNA conformations in the binding process. Therefore, the thermodynamic driving forces and the mechanisms of ht-DNA G-quadruplex-ligand recognition remain poorly understood. In this work we characterize thermodynamically and structurally binding of netropsin (Net), dibenzotetraaza[14]annulene derivatives (DP77, DP78), cationic porphyrin (TMPyP4) and two bisquinolini...

  6. Bexarotene ligand pharmaceuticals.

    Science.gov (United States)

    Hurst, R E

    2000-12-01

    Bexarotene (LGD-1069), from Ligand, was the first retinoid X receptor (RXR)-selective, antitumor retinoid to enter clinical trials. The company launched the drug for the treatment of cutaneous T-cell lymphoma (CTCL), as Targretin capsules, in the US in January 2000 [359023]. The company filed an NDA for Targretin capsules in June 1999, and for topical gel in December 1999 [329011], [349982] specifically for once-daily oral administration for the treatment of patients with early-stage CTCL who have not tolerated other therapies, patients with refractory or persistent early stage CTCL and patients with refractory advanced stage CTCL. The FDA approved Targretin capsules at the end of December 1999 for once-daily oral treatment of all stages of CTCL in patients refractory to at least one prior systemic therapy, at an initial dose of 300 mg/m2/day. After an NDA was submitted in December 1999 for Targretin gel, the drug received Priority Review status for use as a treatment of cutaneous lesions in patients with stage IA, IB or IIA CTCL [354836]. The FDA issued an approvable letter in June 2000, and granted marketing clearance for CTCL in the same month [370687], [372768], [372769], [373279]. Ligand had received Orphan Drug designation for this indication [329011]. At the request of the FDA, Ligand agreed to carry out certain post-approval phase IV and pharmacokinetic studies [351604]. The company filed an MAA with the EMEA for Targretin Capsules to treat lymphoma in November 1999 [348944]. The NDA for Targretin gel is based on a multicenter phase III trial that was conducted in the US, Canada, Europe and Australia involving 50 patients and a multicenter phase I/II clinical program involving 67 patients. Targretin gel was evaluated for the treatment of patients with early stage CTCL (IA-IIA) who were refractory to, intolerant to, or reached a response plateau for at least 6 months on at least two prior therapies. Efficacy results exceeded the protocol-defined response

  7. Face Detection and Recognition

    National Research Council Canada - National Science Library

    Jain, Anil K

    2004-01-01

    This report describes research efforts towards developing algorithms for a robust face recognition system to overcome many of the limitations found in existing two-dimensional facial recognition systems...

  8. Natural Cytotoxicity Receptors: Pattern Recognition and Involvement of Carbohydrates

    Directory of Open Access Journals (Sweden)

    Angel Porgador

    2005-01-01

    Full Text Available Natural cytotoxicity receptors (NCRs, expressed by natural killer (NK cells, trigger NK lysis of tumor and virus-infected cells on interaction with cell-surface ligands of these target cells. We have determined that viral hemagglutinins expressed on the surface of virus-infected cells are involved in the recognition by the NCRs, NKp44 and NKp46. Recognition of tumor cells by the NCRs NKp30 and NKp46 involves heparan sulfate epitopes expressed on the tumor cell membrane. Our studies provide new evidence for the identity of the ligands for NCRs and indicate that a broader definition should be applied to pathological patterns recognized by innate immune receptors. Since nonmicrobial endogenous carbohydrate structures contribute significantly to this recognition, there is an imperative need to develop appropriate tools for the facile sequencing of carbohydrate moieties.

  9. Graphical symbol recognition

    OpenAIRE

    K.C. , Santosh; Wendling , Laurent

    2015-01-01

    International audience; The chapter focuses on one of the key issues in document image processing i.e., graphical symbol recognition. Graphical symbol recognition is a sub-field of a larger research domain: pattern recognition. The chapter covers several approaches (i.e., statistical, structural and syntactic) and specially designed symbol recognition techniques inspired by real-world industrial problems. It, in general, contains research problems, state-of-the-art methods that convey basic s...

  10. Speech-in-Speech Recognition: A Training Study

    Science.gov (United States)

    Van Engen, Kristin J.

    2012-01-01

    This study aims to identify aspects of speech-in-noise recognition that are susceptible to training, focusing on whether listeners can learn to adapt to target talkers ("tune in") and learn to better cope with various maskers ("tune out") after short-term training. Listeners received training on English sentence recognition in…

  11. Novel Techniques for Dialectal Arabic Speech Recognition

    CERN Document Server

    Elmahdy, Mohamed; Minker, Wolfgang

    2012-01-01

    Novel Techniques for Dialectal Arabic Speech describes approaches to improve automatic speech recognition for dialectal Arabic. Since speech resources for dialectal Arabic speech recognition are very sparse, the authors describe how existing Modern Standard Arabic (MSA) speech data can be applied to dialectal Arabic speech recognition, while assuming that MSA is always a second language for all Arabic speakers. In this book, Egyptian Colloquial Arabic (ECA) has been chosen as a typical Arabic dialect. ECA is the first ranked Arabic dialect in terms of number of speakers, and a high quality ECA speech corpus with accurate phonetic transcription has been collected. MSA acoustic models were trained using news broadcast speech. In order to cross-lingually use MSA in dialectal Arabic speech recognition, the authors have normalized the phoneme sets for MSA and ECA. After this normalization, they have applied state-of-the-art acoustic model adaptation techniques like Maximum Likelihood Linear Regression (MLLR) and M...

  12. Structural hierarchy controlling dimerization and target DNA recognition in the AHR transcriptional complex

    Energy Technology Data Exchange (ETDEWEB)

    Seok, Seung-Hyeon; Lee, Woojong; Jiang, Li; Molugu, Kaivalya; Zheng, Aiping; Li, Yitong; Park, Sanghyun; Bradfield, Christopher A.; Xing, Yongna (UW)

    2017-04-10

    he aryl hydrocarbon receptor (AHR) belongs to the PAS (PER-ARNT-SIM) family transcription factors and mediates broad responses to numerous environmental pollutants and cellular metabolites, modulating diverse biological processes from adaptive metabolism, acute toxicity, to normal physiology of vascular and immune systems. The AHR forms a transcriptionally active heterodimer with ARNT (AHR nuclear translocator), which recognizes the dioxin response element (DRE) in the promoter of downstream genes. We determined the crystal structure of the mammalian AHR–ARNT heterodimer in complex with the DRE, in which ARNT curls around AHR into a highly intertwined asymmetric architecture, with extensive heterodimerization interfaces and AHR interdomain interactions. Specific recognition of the DRE is determined locally by the DNA-binding residues, which discriminates it from the closely related hypoxia response element (HRE), and is globally affected by the dimerization interfaces and interdomain interactions. Changes at the interdomain interactions caused either AHR constitutive nuclear localization or failure to translocate to nucleus, underlying an allosteric structural pathway for mediating ligand-induced exposure of nuclear localization signal. These observations, together with the global higher flexibility of the AHR PAS-A and its loosely packed structural elements, suggest a dynamic structural hierarchy for complex scenarios of AHR activation induced by its diverse ligands.

  13. The Recognition Heuristic: A Review of Theory and Tests

    Science.gov (United States)

    Pachur, Thorsten; Todd, Peter M.; Gigerenzer, Gerd; Schooler, Lael J.; Goldstein, Daniel G.

    2011-01-01

    The recognition heuristic is a prime example of how, by exploiting a match between mind and environment, a simple mental strategy can lead to efficient decision making. The proposal of the heuristic initiated a debate about the processes underlying the use of recognition in decision making. We review research addressing four key aspects of the recognition heuristic: (a) that recognition is often an ecologically valid cue; (b) that people often follow recognition when making inferences; (c) that recognition supersedes further cue knowledge; (d) that its use can produce the less-is-more effect – the phenomenon that lesser states of recognition knowledge can lead to more accurate inferences than more complete states. After we contrast the recognition heuristic to other related concepts, including availability and fluency, we carve out, from the existing findings, some boundary conditions of the use of the recognition heuristic as well as key questions for future research. Moreover, we summarize developments concerning the connection of the recognition heuristic with memory models. We suggest that the recognition heuristic is used adaptively and that, compared to other cues, recognition seems to have a special status in decision making. Finally, we discuss how systematic ignorance is exploited in other cognitive mechanisms (e.g., estimation and preference). PMID:21779266

  14. Recognition and Toleration

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    Recognition and toleration are ways of relating to the diversity characteristic of multicultural societies. The article concerns the possible meanings of toleration and recognition, and the conflict that is often claimed to exist between these two approaches to diversity. Different forms...... or interpretations of recognition and toleration are considered, confusing and problematic uses of the terms are noted, and the compatibility of toleration and recognition is discussed. The article argues that there is a range of legitimate and importantly different conceptions of both toleration and recognition...

  15. Potential ligand-binding residues in rat olfactory receptors identified by correlated mutation analysis

    Science.gov (United States)

    Singer, M. S.; Oliveira, L.; Vriend, G.; Shepherd, G. M.

    1995-01-01

    A family of G-protein-coupled receptors is believed to mediate the recognition of odor molecules. In order to identify potential ligand-binding residues, we have applied correlated mutation analysis to receptor sequences from the rat. This method identifies pairs of sequence positions where residues remain conserved or mutate in tandem, thereby suggesting structural or functional importance. The analysis supported molecular modeling studies in suggesting several residues in positions that were consistent with ligand-binding function. Two of these positions, dominated by histidine residues, may play important roles in ligand binding and could confer broad specificity to mammalian odor receptors. The presence of positive (overdominant) selection at some of the identified positions provides additional evidence for roles in ligand binding. Higher-order groups of correlated residues were also observed. Each group may interact with an individual ligand determinant, and combinations of these groups may provide a multi-dimensional mechanism for receptor diversity.

  16. Estimation of kinetic and thermodynamic ligand-binding parameters using computational strategies.

    Science.gov (United States)

    Deganutti, Giuseppe; Moro, Stefano

    2017-04-01

    Kinetic and thermodynamic ligand-protein binding parameters are gaining growing importance as key information to consider in drug discovery. The determination of the molecular structures, using particularly x-ray and NMR techniques, is crucial for understanding how a ligand recognizes its target in the final binding complex. However, for a better understanding of the recognition processes, experimental studies of ligand-protein interactions are needed. Even though several techniques can be used to investigate both thermodynamic and kinetic profiles for a ligand-protein complex, these procedures are very often laborious, time consuming and expensive. In the last 10 years, computational approaches have enormous potential in providing insights into each of the above effects and in parsing their contributions to the changes in both kinetic and thermodynamic binding parameters. The main purpose of this review is to summarize the state of the art of computational strategies for estimating the kinetic and thermodynamic parameters of a ligand-protein binding.

  17. Ligand Depot: a data warehouse for ligands bound to macromolecules.

    Science.gov (United States)

    Feng, Zukang; Chen, Li; Maddula, Himabindu; Akcan, Ozgur; Oughtred, Rose; Berman, Helen M; Westbrook, John

    2004-09-01

    Ligand Depot is an integrated data resource for finding information about small molecules bound to proteins and nucleic acids. The initial release (version 1.0, November, 2003) focuses on providing chemical and structural information for small molecules found as part of the structures deposited in the Protein Data Bank. Ligand Depot accepts keyword-based queries and also provides a graphical interface for performing chemical substructure searches. A wide variety of web resources that contain information on small molecules may also be accessed through Ligand Depot. Ligand Depot is available at http://ligand-depot.rutgers.edu/. Version 1.0 supports multiple operating systems including Windows, Unix, Linux and the Macintosh operating system. The current drawing tool works in Internet Explorer, Netscape and Mozilla on Windows, Unix and Linux.

  18. PANP is a novel O-glycosylated PILR{alpha} ligand expressed in neural tissues

    Energy Technology Data Exchange (ETDEWEB)

    Kogure, Amane [Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871 (Japan); Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Osaka 565-0871 (Japan); Shiratori, Ikuo [Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871 (Japan); Wang, Jing [Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871 (Japan); Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Osaka 565-0871 (Japan); Lanier, Lewis L. [Department of Microbiology and Immunology and the Cancer Research Institute, University of California San Francisco, San Francisco, CA 94143 (United States); Arase, Hisashi, E-mail: arase@biken.osaka-u.ac.jp [Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871 (Japan); Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Osaka 565-0871 (Japan); JST CREST, Saitama 332-0012 (Japan)

    2011-02-18

    Research highlights: {yields} A Novel molecule, PANP, was identified to be a PILR{alpha} ligand. {yields} Sialylated O-glycan structures on PANP were required for PILR{alpha} recognition. {yields} Transcription of PANP was mainly observed in neural tissues. {yields} PANP seems to be involved in immune regulation as a ligand for PILR{alpha}. -- Abstract: PILR{alpha} is an immune inhibitory receptor possessing an immunoreceptor tyrosine-based inhibitory motif (ITIM) in its cytoplasmic domain enabling it to deliver inhibitory signals. Binding of PILR{alpha} to its ligand CD99 is involved in immune regulation; however, whether there are other PILR{alpha} ligands in addition to CD99 is not known. Here, we report that a novel molecule, PILR-associating neural protein (PANP), acts as an additional ligand for PILR{alpha}. Transcription of PANP was mainly observed in neural tissues. PILR{alpha}-Ig fusion protein bound cells transfected with PANP and the transfectants stimulated PILR{alpha} reporter cells. Specific O-glycan structures on PANP were found to be required for PILR recognition of this ligand. These results suggest that PANP is involved in immune regulation as a ligand of the PILR{alpha}.

  19. Water networks contribute to enthalpy/entropy compensation in protein-ligand binding.

    Science.gov (United States)

    Breiten, Benjamin; Lockett, Matthew R; Sherman, Woody; Fujita, Shuji; Al-Sayah, Mohammad; Lange, Heiko; Bowers, Carleen M; Heroux, Annie; Krilov, Goran; Whitesides, George M

    2013-10-16

    The mechanism (or mechanisms) of enthalpy-entropy (H/S) compensation in protein-ligand binding remains controversial, and there are still no predictive models (theoretical or experimental) in which hypotheses of ligand binding can be readily tested. Here we describe a particularly well-defined system of protein and ligands--human carbonic anhydrase (HCA) and a series of benzothiazole sulfonamide ligands with different patterns of fluorination--that we use to define enthalpy/entropy (H/S) compensation in this system thermodynamically and structurally. The binding affinities of these ligands (with the exception of one ligand, in which the deviation is understood) to HCA are, despite differences in fluorination pattern, indistinguishable; they nonetheless reflect significant and compensating changes in enthalpy and entropy of binding. Analysis reveals that differences in the structure and thermodynamic properties of the waters surrounding the bound ligands are an important contributor to the observed H/S compensation. These results support the hypothesis that the molecules of water filling the active site of a protein, and surrounding the ligand, are as important as the contact interactions between the protein and the ligand for biomolecular recognition, and in determining the thermodynamics of binding.

  20. Residue preference mapping of ligand fragments in the Protein Data Bank.

    Science.gov (United States)

    Wang, Lirong; Xie, Zhaojun; Wipf, Peter; Xie, Xiang-Qun

    2011-04-25

    The interaction between small molecules and proteins is one of the major concerns for structure-based drug design because the principles of protein-ligand interactions and molecular recognition are not thoroughly understood. Fortunately, the analysis of protein-ligand complexes in the Protein Data Bank (PDB) enables unprecedented possibilities for new insights. Herein, we applied molecule-fragmentation algorithms to split the ligands extracted from PDB crystal structures into small fragments. Subsequently, we have developed a ligand fragment and residue preference mapping (LigFrag-RPM) algorithm to map the profiles of the interactions between these fragments and the 20 proteinogenic amino acid residues. A total of 4032 fragments were generated from 71 798 PDB ligands by a ring cleavage (RC) algorithm. Among these ligand fragments, 315 unique fragments were characterized with the corresponding fragment-residue interaction profiles by counting residues close to these fragments. The interaction profiles revealed that these fragments have specific preferences for certain types of residues. The applications of these interaction profiles were also explored and evaluated in case studies, showing great potential for the study of protein-ligand interactions and drug design. Our studies demonstrated that the fragment-residue interaction profiles generated from the PDB ligand fragments can be used to detect whether these fragments are in their favorable or unfavorable environments. The algorithm for a ligand fragment and residue preference mapping (LigFrag-RPM) developed here also has the potential to guide lead chemistry modifications as well as binding residues predictions.

  1. Melatonin: functions and ligands.

    Science.gov (United States)

    Singh, Mahaveer; Jadhav, Hemant R

    2014-09-01

    Melatonin is a chronobiotic substance that acts as synchronizer by stabilizing bodily rhythms. Its synthesis occurs in various locations throughout the body, including the pineal gland, skin, lymphocytes and gastrointestinal tract (GIT). Its synthesis and secretion is controlled by light and dark conditions, whereby light decreases and darkness increases its production. Thus, melatonin is also known as the 'hormone of darkness'. Melatonin and analogs that bind to the melatonin receptors are important because of their role in the management of depression, insomnia, epilepsy, Alzheimer's disease (AD), diabetes, obesity, alopecia, migraine, cancer, and immune and cardiac disorders. In this review, we discuss the mechanism of action of melatonin in these disorders, which could aid in the design of novel melatonin receptor ligands. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Pattern Recognition via the Toll-Like Receptor System in the Human Female Genital Tract

    Directory of Open Access Journals (Sweden)

    Kaei Nasu

    2010-01-01

    Full Text Available The mucosal surface of the female genital tract is a complex biosystem, which provides a barrier against the outside world and participates in both innate and acquired immune defense systems. This mucosal compartment has adapted to a dynamic, non-sterile environment challenged by a variety of antigenic/inflammatory stimuli associated with sexual intercourse and endogenous vaginal microbiota. Rapid innate immune defenses against microbial infection usually involve the recognition of invading pathogens by specific pattern-recognition receptors recently attributed to the family of Toll-like receptors (TLRs. TLRs recognize conserved pathogen-associated molecular patterns (PAMPs synthesized by microorganisms including bacteria, fungi, parasites, and viruses as well as endogenous ligands associated with cell damage. Members of the TLR family, which includes 10 human TLRs identified to date, recognize distinct PAMPs produced by various bacterial, fungal, and viral pathogens. The available literature regarding the innate immune system of the female genital tract during human reproductive processes was reviewed in order to identify studies specifically related to the expression and function of TLRs under normal as well as pathological conditions. Increased understanding of these molecules may provide insight into site-specific immunoregulatory mechanisms in the female reproductive tract.

  3. Extended Target Recognition in Cognitive Radar Networks

    Directory of Open Access Journals (Sweden)

    Xiqin Wang

    2010-11-01

    Full Text Available We address the problem of adaptive waveform design for extended target recognition in cognitive radar networks. A closed-loop active target recognition radar system is extended to the case of a centralized cognitive radar network, in which a generalized likelihood ratio (GLR based sequential hypothesis testing (SHT framework is employed. Using Doppler velocities measured by multiple radars, the target aspect angle for each radar is calculated. The joint probability of each target hypothesis is then updated using observations from different radar line of sights (LOS. Based on these probabilities, a minimum correlation algorithm is proposed to adaptively design the transmit waveform for each radar in an amplitude fluctuation situation. Simulation results demonstrate performance improvements due to the cognitive radar network and adaptive waveform design. Our minimum correlation algorithm outperforms the eigen-waveform solution and other non-cognitive waveform design approaches.

  4. Reversible Size Control of Silver Nanoclusters via Ligand-exchange

    KAUST Repository

    Bootharaju, Megalamane Siddaramappa

    2015-05-21

    The properties of atomically monodisperse noble metal nanoclusters (NCs) are intricately intertwined with their precise molecular formula. The vast majority of size-specific NC syntheses start from the reduction of the metal salt and thiol ligand mixture. Only in gold was it recently shown that ligand-exchange could induce the growth of NCs from one atomically precise species to another; a process of yet unknown reversibility. Here, we present a process for the ligand-exchange-induced growth of atomically precise silver NCs, in a biphasic liquid-liquid system, which is particularly of interest because of its complete reversibility and ability to occur at room temperature. We explore this phenomenon in-depth using Ag35(SG)18 [SG= glutathionate] and Ag44(4-FTP)30 [4-FTP= 4-fluorothiophenol] as model systems. We show that the ligand-exchange conversion of Ag35(SG)18 into Ag44(4-FTP)30 is rapid (< 5 min) and direct, while the reverse process proceeds slowly through intermediate cluster sizes. We adapt a recently developed theory of reverse Ostwald ripening to model the NCs’ interconvertibility. The model’s predictions are in good agreement with the experimental observations, and they highlight the importance of small changes in the ligand-metal binding energy in determining the final equilibrium NC size. Based on the insight provided by this model, we demonstrated experimentally that by varying the choice of ligands, ligand-exchange can be used to obtain different sized NCs. The findings in this work establish ligand-exchange as a versatile tool for tuning cluster sizes.

  5. A selection fit mechanism in BMP receptor IA as a possible source for BMP ligand-receptor promiscuity.

    Directory of Open Access Journals (Sweden)

    Stefan Harth

    Full Text Available BACKGROUND: Members of the TGF-β superfamily are characterized by a highly promiscuous ligand-receptor interaction as is readily apparent from the numeral discrepancy of only seven type I and five type II receptors available for more than 40 ligands. Structural and functional studies have been used to address the question of how specific signals can be deduced from a limited number of receptor combinations and to unravel the molecular mechanisms underlying the protein-protein recognition that allow such limited specificity. PRINCIPAL FINDINGS: In this study we have investigated how an antigen binding antibody fragment (Fab raised against the extracellular domain of the BMP receptor type IA (BMPR-IA recognizes the receptor's BMP-2 binding epitope and thereby neutralizes BMP-2 receptor activation. The crystal structure of the complex of the BMPR-IA ectodomain bound to the Fab AbD1556 revealed that the contact surface of BMPR-IA overlaps extensively with the contact surface for BMP-2 interaction. Although the structural epitopes of BMPR-IA to both binding partners coincides, the structures of BMPR-IA in the two complexes differ significantly. In contrast to the structural differences, alanine-scanning mutagenesis of BMPR-IA showed that the functional determinants for binding to the antibody and BMP-2 are almost identical. CONCLUSIONS: Comparing the structures of BMPR-IA bound to BMP-2 or bound to the Fab AbD1556 with the structure of unbound BMPR-IA shows that binding of BMPR-IA to its interaction partners follows a selection fit mechanism, possibly indicating that the ligand promiscuity of BMPR-IA is inherently encoded by structural adaptability. The functional and structural analysis of the BMPR-IA binding antibody AbD1556 mimicking the BMP-2 binding epitope may thus pave the way for the design of low-molecular weight synthetic receptor binders/inhibitors.

  6. Compact Acoustic Models for Embedded Speech Recognition

    Directory of Open Access Journals (Sweden)

    Christophe Lévy

    2009-01-01

    Full Text Available Speech recognition applications are known to require a significant amount of resources. However, embedded speech recognition only authorizes few KB of memory, few MIPS, and small amount of training data. In order to fit the resource constraints of embedded applications, an approach based on a semicontinuous HMM system using state-independent acoustic modelling is proposed. A transformation is computed and applied to the global model in order to obtain each HMM state-dependent probability density functions, authorizing to store only the transformation parameters. This approach is evaluated on two tasks: digit and voice-command recognition. A fast adaptation technique of acoustic models is also proposed. In order to significantly reduce computational costs, the adaptation is performed only on the global model (using related speaker recognition adaptation techniques with no need for state-dependent data. The whole approach results in a relative gain of more than 20% compared to a basic HMM-based system fitting the constraints.

  7. Multimodal eye recognition

    Science.gov (United States)

    Zhou, Zhi; Du, Yingzi; Thomas, N. L.; Delp, Edward J., III

    2010-04-01

    Multimodal biometrics use more than one means of biometric identification to achieve higher recognition accuracy, since sometimes a unimodal biometric is not good enough used to do identification and classification. In this paper, we proposed a multimodal eye recognition system, which can obtain both iris and sclera patterns from one color eye image. Gabor filter and 1-D Log-Gabor filter algorithms have been applied as the iris recognition algorithms. In sclera recognition, we introduced automatic sclera segmentation, sclera pattern enhancement, sclera pattern template generation, and sclera pattern matching. We applied kernelbased matching score fusion to improve the performance of the eye recognition system. The experimental results show that the proposed eye recognition method can achieve better performance compared to unimodal biometric identification, and the accuracy of our proposed kernel-based matching score fusion method is higher than two classic linear matching score fusion methods: Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA).

  8. Spatio-temporal regulation of Hsp90-ligand complex leads to immune activation.

    Directory of Open Access Journals (Sweden)

    Yasuaki eTamura

    2016-05-01

    Full Text Available Hsp90 is the most abundant cytosolic HSP and is known to act as a molecular chaperone. We found that an Hsp90-cancer antigen peptide complex was efficiently cross-presented by human monocyte-derived dendritic cells and induced peptide-specific cytotoxic T lymphocytes. Furthermore, we observed that the internalized Hsp90-peptide complex was strictly sorted to the Rab5+, EEA1+ static early endosome and the Hsp90-chaperoned peptide was processed and bound to MHC class I molecules through a endosome-recycling pathway. We also found that extracellular Hsp90 complexed with CpG-A or self-DNA stimulates production of a large amount of IFN-α from pDCs via static early endosome targeting. Thus, extracellular Hsp90 can target the antigen or nucleic acid to a static early endosome by spatio-temporal regulation. Moreover, we showed that Hsp90 associates with and delivers TLR7/9 from the ER to early endosomes for ligand recognition. Hsp90 inhibitor, geldanamycin derivative inhibited the Hsp90 association with TLR7/9, resulting in inhibition IFN-α production, leading to improvement of SLE symptoms. Interstingly, we observed that serum Hsp90 is clearly increased in patients with active SLE compared with that in patients with inactive disease. Serum Hsp90 detected in SLE patients binds to self-DNA and/or anti-DNA Ab, thus leading to stimulation of pDCs to produce IFN-α. Thus, Hsp90 plays a crucial role in the pathogenesis of SLE and that an Hsp90 inhibitor will therefore provide a new therapeutic approach to SLE and other nucleic acid-related autoimmune diseases. We will discuss how spatio-temporal regulation of Hsp90-ligand complexes within antigen-presenting cells affects the innate immunity and adaptive immunity.

  9. 2-deoxy D-glucose prevents cell surface expression of NKG2D ligands through inhibition of N-linked glycosylation

    DEFF Research Database (Denmark)

    Andresen, Lars; Skovbakke, Sarah Line; Persson, Gry

    2012-01-01

    NKG2D ligand surface expression is important for immune recognition of stressed and neotransformed cells. In this study, we show that surface expression of MICA/B and other NKG2D ligands is dependent on N-linked glycosylation. The inhibitor of glycolysis and N-linked glycosylation, 2-deoxy...

  10. Pattern recognition & machine learning

    CERN Document Server

    Anzai, Y

    1992-01-01

    This is the first text to provide a unified and self-contained introduction to visual pattern recognition and machine learning. It is useful as a general introduction to artifical intelligence and knowledge engineering, and no previous knowledge of pattern recognition or machine learning is necessary. Basic for various pattern recognition and machine learning methods. Translated from Japanese, the book also features chapter exercises, keywords, and summaries.

  11. Statistical Pattern Recognition

    CERN Document Server

    Webb, Andrew R

    2011-01-01

    Statistical pattern recognition relates to the use of statistical techniques for analysing data measurements in order to extract information and make justified decisions.  It is a very active area of study and research, which has seen many advances in recent years. Applications such as data mining, web searching, multimedia data retrieval, face recognition, and cursive handwriting recognition, all require robust and efficient pattern recognition techniques. This third edition provides an introduction to statistical pattern theory and techniques, with material drawn from a wide range of fields,

  12. Vesicular stomatitis virus infection promotes immune evasion by preventing NKG2D-ligand surface expression.

    Science.gov (United States)

    Jensen, Helle; Andresen, Lars; Nielsen, Jens; Christensen, Jan Pravsgaard; Skov, Søren

    2011-01-01

    Vesicular stomatitis virus (VSV) has recently gained attention for its oncolytic ability in cancer treatment. Initially, we hypothesized that VSV infection could increase immune recognition of cancer cells through induction of the immune stimulatory NKG2D-ligands. Here we show that VSV infection leads to a robust induction of MICA mRNA expression, however the subsequent surface expression is potently hindered. Thus, VSV lines up with human cytomegalovirus (HCMV) and adenovirus, which actively subvert the immune system by negatively affecting NKG2D-ligand surface expression. VSV infection caused an active suppression of NKG2D-ligand surface expression, affecting both endogenous and histone deacetylase (HDAC)-inhibitor induced MICA, MICB and ULBP-2 expression. The classical immune escape mechanism of VSV (i.e., the M protein blockade of nucleocytoplasmic mRNA transport) was not involved, as the VSV mutant strain, VSV(ΔM51), which possess a defective M protein, prevented MICA surface expression similarly to wild-type VSV. The VSV mediated down modulation of NKG2D-ligand expression did not involve apoptosis. Constitutive expression of MICA bypassed the escape mechanism, suggesting that VSV affect NKG2D-ligand expression at an early post-transcriptional level. Our results show that VSV possess an escape mechanism, which could affect the immune recognition of VSV infected cancer cells. This may also have implications for immune recognition of cancer cells after combined treatment with VSV and chemotherapeutic drugs.

  13. Vesicular Stomatitis Virus Infection Promotes Immune Evasion by Preventing NKG2D-Ligand Surface Expression

    DEFF Research Database (Denmark)

    Jensen, Helle; Andresen, Lars; Nielsen, Jens

    2011-01-01

    Vesicular stomatitis virus (VSV) has recently gained attention for its oncolytic ability in cancer treatment. Initially, we hypothesized that VSV infection could increase immune recognition of cancer cells through induction of the immune stimulatory NKG2D-ligands. Here we show that VSV infection ...

  14. Glutamate receptor ligands

    DEFF Research Database (Denmark)

    Guldbrandt, Mette; Johansen, Tommy N; Frydenvang, Karla Andrea

    2002-01-01

    Homologation and substitution on the carbon backbone of (S)-glutamic acid [(S)-Glu, 1], as well as absolute stereochemistry, are structural parameters of key importance for the pharmacological profile of (S)-Glu receptor ligands. We describe a series of methyl-substituted 2-aminoadipic acid (AA...... or slightly lower potencies than (S)-AA [e.g., EC(50) = 76 microM for (2S,4S)-4-methyl-AA (5a) as compared to EC(50) = 35 microM for (S)-AA]. The position of the methyl substituent had a profound effect on the observed pharmacology, whereas the absolute stereochemistry at the methylated carbon atom had a very......) analogs, and the synthesis, stereochemistry, and enantiopharmacology of 3-methyl-AA (4a-d), 4-methyl-AA (5a-d), 5-methyl-AA (6a-d), and (E)-Delta(4)-5-methyl-AA (7a and 7b) are reported. The compounds were resolved using chiral HPLC and the configurational assignments of the enantiomers were based on X...

  15. Support subspaces method for synthetic aperture radar automatic target recognition

    Directory of Open Access Journals (Sweden)

    Vladimir Fursov

    2016-09-01

    Full Text Available This article offers a new object recognition approach that gives high quality using synthetic aperture radar images. The approach includes image preprocessing, clustering and recognition stages. At the image preprocessing stage, we compute the mass centre of object images for better image matching. A conjugation index of a recognition vector is used as a distance function at clustering and recognition stages. We suggest a construction of the so-called support subspaces, which provide high recognition quality with a significant dimension reduction. The results of the experiments demonstrate that the proposed method provides higher recognition quality (97.8% than such methods as support vector machine (95.9%, deep learning based on multilayer auto-encoder (96.6% and adaptive boosting (96.1%. The proposed method is stable for objects processed from different angles.

  16. Pattern recognition principles

    Science.gov (United States)

    Tou, J. T.; Gonzalez, R. C.

    1974-01-01

    The present work gives an account of basic principles and available techniques for the analysis and design of pattern processing and recognition systems. Areas covered include decision functions, pattern classification by distance functions, pattern classification by likelihood functions, the perceptron and the potential function approaches to trainable pattern classifiers, statistical approach to trainable classifiers, pattern preprocessing and feature selection, and syntactic pattern recognition.

  17. Paradigms in object recognition

    International Nuclear Information System (INIS)

    Mutihac, R.; Mutihac, R.C.

    1999-09-01

    A broad range of approaches has been proposed and applied for the complex and rather difficult task of object recognition that involves the determination of object characteristics and object classification into one of many a priori object types. Our paper revises briefly the three main different paradigms in pattern recognition, namely Bayesian statistics, neural networks, and expert systems. (author)

  18. Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440

    Directory of Open Access Journals (Sweden)

    Matilde Fernández

    2017-05-01

    Full Text Available Bacteria have evolved a wide range of chemoreceptors with different ligand specificities. Typically, chemoreceptors bind ligands with elevated specificity and ligands serve as growth substrates. However, there is a chemoreceptor family that has a broad ligand specificity including many compounds that are not of metabolic value. To advance the understanding of this family, we have used the PcaY_PP (PP2643 chemoreceptor of Pseudomonas putida KT2440 as a model. Using Isothermal Titration Calorimetry we showed here that the recombinant ligand binding domain (LBD of PcaY_PP recognizes 17 different C6-ring containing carboxylic acids with KD values between 3.7 and 138 μM and chemoeffector affinity correlated with the magnitude of the chemotactic response. Mutation of the pcaY_PP gene abolished chemotaxis to these compounds; phenotype that was restored following gene complementation. Growth experiments using PcaY_PP ligands as sole C-sources revealed functional relationships between their metabolic potential and affinity for the chemoreceptor. Thus, only 7 PcaY_PP ligands supported growth and their KD values correlated with the length of the bacterial lag phase. Furthermore, PcaY_PP ligands that did not support growth had significantly higher KD values than those that did. The receptor has thus binds preferentially compounds that serve as C-sources and amongst them those that rapidly promote growth. Tightest binding compounds were quinate, shikimate, 3-dehydroshikimate and protocatechuate, which are at the interception of the biosynthetic shikimate and catabolic quinate pathways. Analytical ultracentrifugation studies showed that ligand free PcaY_PP-LBD is present in a monomer-dimer equilibrium (KD = 57.5 μM. Ligand binding caused a complete shift to the dimeric state, which appears to be a general feature of four-helix bundle LBDs. This study indicates that the metabolic potential of compounds is an important parameter in the molecular recognition

  19. Cough Recognition Based on Mel Frequency Cepstral Coefficients and Dynamic Time Warping

    Science.gov (United States)

    Zhu, Chunmei; Liu, Baojun; Li, Ping

    Cough recognition provides important clinical information for the treatment of many respiratory diseases, but the assessment of cough frequency over a long period of time remains unsatisfied for either clinical or research purpose. In this paper, according to the advantage of dynamic time warping (DTW) and the characteristic of cough recognition, an attempt is made to adapt DTW as the recognition algorithm for cough recognition. The process of cough recognition based on mel frequency cepstral coefficients (MFCC) and DTW is introduced. Experiment results of testing samples from 3 subjects show that acceptable performances of cough recognition are obtained by DTW with a small training set.

  20. Challenging ocular image recognition

    Science.gov (United States)

    Pauca, V. Paúl; Forkin, Michael; Xu, Xiao; Plemmons, Robert; Ross, Arun A.

    2011-06-01

    Ocular recognition is a new area of biometric investigation targeted at overcoming the limitations of iris recognition performance in the presence of non-ideal data. There are several advantages for increasing the area beyond the iris, yet there are also key issues that must be addressed such as size of the ocular region, factors affecting performance, and appropriate corpora to study these factors in isolation. In this paper, we explore and identify some of these issues with the goal of better defining parameters for ocular recognition. An empirical study is performed where iris recognition methods are contrasted with texture and point operators on existing iris and face datasets. The experimental results show a dramatic recognition performance gain when additional features are considered in the presence of poor quality iris data, offering strong evidence for extending interest beyond the iris. The experiments also highlight the need for the direct collection of additional ocular imagery.

  1. Recognition and Justice

    Directory of Open Access Journals (Sweden)

    Charles Reagan

    2016-01-01

    The complexities of the meanings of “to recognize” and “recognition” are important in their roles in the realm of justice. I include in the concept of justice, the judiciary, both civil and criminal; distributive justice; and, social and political justice. For each one of these, there are multiple meanings of recognition that are important to understanding their foundation and their scope. There are meanings of recognition that are relevant to other aspects of social justice as the recognition of marginal, oppressed, devalued, groups as deserving of being treated as equals. The structure of my paper is to go through the various meanings and categories of meanings of “to recognize” and “recognition.” I give an account of each of the types of justice and show how various kinds of recognition are relevant to each kind of justice.

  2. Synthesis, Crystal Structure and Luminescent Property of A Novel Cd(II) Coordination Polymer with Bis-imidazole Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yong Hong [Huaibei Normal Univ., Huaibei (China)

    2013-04-15

    The key to the successful design of metal-organic coordination polymers is the judicious selection of organic ligand. Recently, polydentate aromatic nitrogen heterocyclic ligands with five-membered rings have been well-studied in the construction of supramolecular structure for their N-coordinated sites apt to coordinating to transition metals. Similar to six-membered N-heterocyclic ligands, the azole-based five-membered N-heterocyclic ligands, such as imidazoles, triazoles and tetrazoles have been extensively employed in the construction of various coordination polymers with diverse topologies and interesting properties. The bis(azole) ligands in which N-donor azole rings (imidazole, triazole, or tetrazole) are separated by alkyl, (CH{sub 2}){sub n}, spacers are good choices for flexible bridging ligands. The conformational flexibility of the spacers makes the ligands adaptable to various coordination networks with one-, two-, and three dimensional structures.

  3. Ligand-guided receptor optimization.

    Science.gov (United States)

    Katritch, Vsevolod; Rueda, Manuel; Abagyan, Ruben

    2012-01-01

    Receptor models generated by homology or even obtained by crystallography often have their binding pockets suboptimal for ligand docking and virtual screening applications due to insufficient accuracy or induced fit bias. Knowledge of previously discovered receptor ligands provides key information that can be used for improving docking and screening performance of the receptor. Here, we present a comprehensive ligand-guided receptor optimization (LiBERO) algorithm that exploits ligand information for selecting the best performing protein models from an ensemble. The energetically feasible protein conformers are generated through normal mode analysis and Monte Carlo conformational sampling. The algorithm allows iteration of the conformer generation and selection steps until convergence of a specially developed fitness function which quantifies the conformer's ability to select known ligands from decoys in a small-scale virtual screening test. Because of the requirement for a large number of computationally intensive docking calculations, the automated algorithm has been implemented to use Linux clusters allowing easy parallel scaling. Here, we will discuss the setup of LiBERO calculations, selection of parameters, and a range of possible uses of the algorithm which has already proven itself in several practical applications to binding pocket optimization and prospective virtual ligand screening.

  4. Adaptive metric kernel regression

    DEFF Research Database (Denmark)

    Goutte, Cyril; Larsen, Jan

    2000-01-01

    Kernel smoothing is a widely used non-parametric pattern recognition technique. By nature, it suffers from the curse of dimensionality and is usually difficult to apply to high input dimensions. In this contribution, we propose an algorithm that adapts the input metric used in multivariate...... regression by minimising a cross-validation estimate of the generalisation error. This allows to automatically adjust the importance of different dimensions. The improvement in terms of modelling performance is illustrated on a variable selection task where the adaptive metric kernel clearly outperforms...

  5. Adaptive Metric Kernel Regression

    DEFF Research Database (Denmark)

    Goutte, Cyril; Larsen, Jan

    1998-01-01

    Kernel smoothing is a widely used nonparametric pattern recognition technique. By nature, it suffers from the curse of dimensionality and is usually difficult to apply to high input dimensions. In this paper, we propose an algorithm that adapts the input metric used in multivariate regression...... by minimising a cross-validation estimate of the generalisation error. This allows one to automatically adjust the importance of different dimensions. The improvement in terms of modelling performance is illustrated on a variable selection task where the adaptive metric kernel clearly outperforms the standard...

  6. Fast Pedestrian Recognition Based on Multisensor Fusion

    Directory of Open Access Journals (Sweden)

    Hongyu Hu

    2012-01-01

    Full Text Available A fast pedestrian recognition algorithm based on multisensor fusion is presented in this paper. Firstly, potential pedestrian locations are estimated by laser radar scanning in the world coordinates, and then their corresponding candidate regions in the image are located by camera calibration and the perspective mapping model. For avoiding time consuming in the training and recognition process caused by large numbers of feature vector dimensions, region of interest-based integral histograms of oriented gradients (ROI-IHOG feature extraction method is proposed later. A support vector machine (SVM classifier is trained by a novel pedestrian sample dataset which adapt to the urban road environment for online recognition. Finally, we test the validity of the proposed approach with several video sequences from realistic urban road scenarios. Reliable and timewise performances are shown based on our multisensor fusing method.

  7. Design and Formation of a Large, Tetrahedral, Metal-ligand Cluster Using 1,1'-Binaphthyl Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Biros, Shannon M.; Yeh, Robert M.; Raymond, Kenneth N.

    2008-03-13

    Many chemists have been fascinated with the development of discrete supramolecular structures that encapsulate guest molecules. These structures can be assembled through covalent or hydrogen bonds, electrostatic or metal-ligand interactions. These host structures have provided valuable insight into the forces involved in small molecule recognition. Our work has focused on the design and study of metal-ligand clusters of varying sizes. The naphthalene [M{sub 4}L{sub 6}]{sup 12-} cluster 1, shown in Figure 1, has demonstrated diastereoselective guest binding and chiral induction properties as well as the ability to catalyze reactions carried out inside the cavity in an enzyme-like manner. However, the size of the cavity (ca. 300-500 {angstrom}{sup 3}) has often limited the scope of substrates for these transformations.

  8. Novel olfactory ligands via terpene synthases.

    Science.gov (United States)

    Touchet, Sabrina; Chamberlain, Keith; Woodcock, Christine M; Miller, David J; Birkett, Michael A; Pickett, John A; Allemann, Rudolf K

    2015-05-01

    A synthetic biology approach to the rational design of analogues of olfactory ligands by providing unnatural substrates for the enzyme synthesising (S)-germacrene D, an olfactory ligand acting as a plant derived insect repellent, to produce novel ligands is described as a viable alternative to largely unsuccessful ligand docking studies. (S)-14,15-Dimethylgermacrene D shows an unexpected reversal in behavioural activity.

  9. Innate immune recognition of the microbiota promotes host-microbial symbiosis

    OpenAIRE

    Chu, Hiutung; Mazmanian, Sarkis K.

    2013-01-01

    Pattern recognition receptors (PRRs) are traditionally known to recognize microbial molecules during infection to initiate inflammatory responses. However, ligands for PRRs are not exclusive to pathogens, and are abundantly produced by the resident microbiota during normal colonization. Mechanism(s) that underlie this paradox have remained unclear. Recent studies reveal that gut bacterial ligands from the microbiota signal through PRRs to promote host tissue and immune development, and protec...

  10. Recognition memory in noise for speech of varying intelligibility.

    Science.gov (United States)

    Gilbert, Rachael C; Chandrasekaran, Bharath; Smiljanic, Rajka

    2014-01-01

    This study investigated the extent to which noise impacts normal-hearing young adults' speech processing of sentences that vary in intelligibility. Intelligibility and recognition memory in noise were examined for conversational and clear speech sentences recorded in quiet (quiet speech, QS) and in response to the environmental noise (noise-adapted speech, NAS). Results showed that (1) increased intelligibility through conversational-to-clear speech modifications led to improved recognition memory and (2) NAS presented a more naturalistic speech adaptation to noise compared to QS, leading to more accurate word recognition and enhanced sentence recognition memory. These results demonstrate that acoustic-phonetic modifications implemented in listener-oriented speech enhance speech-in-noise processing beyond word recognition. Effortful speech processing in challenging listening environments can thus be improved by speaking style adaptations on the part of the talker. In addition to enhanced intelligibility, a substantial improvement in recognition memory can be achieved through speaker adaptations to the environment and to the listener when in adverse conditions.

  11. Contrasting roles for TLR ligands in HIV-1 pathogenesis.

    Directory of Open Access Journals (Sweden)

    Beda Brichacek

    2010-09-01

    Full Text Available The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs. Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs 5 and 9, we examined their effect on human immunodeficiency virus (HIV-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist treatment enhanced replication of CC chemokine receptor 5 (CCR 5-tropic and CXC chemokine receptor 4 (CXCR4-tropic HIV-1, treatment with oligodeoxynucleotide (ODN M362 (TLR9 agonist suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention.

  12. Dual Recognition of Human Telomeric G-quadruplex by Neomycin-anthraquinone Conjugate

    Science.gov (United States)

    Ranjan, Nihar; Davis, Erik; Xue, Liang

    2013-01-01

    The authors report the recognition of a G-quadruplex formed by four repeat human telomeric DNA with aminosugar intercalator conjugates. The recognition of G-quadruplex through dual binding mode ligands significantly increased the affinity of ligands for G-quadruplex. One such example is a neomycin-anthraquinone 2 which exhibited nanomolar affinity for the quadruplex, and the affinity of 2 is nearly 1000 fold higher for human telomeric G-quadruplex DNA than its constituent units, neomycin and anthraquinone. PMID:23698792

  13. Bacteriophages as recognition and identification agents

    International Nuclear Information System (INIS)

    Teodorescu, M.C.; Gaspar, Alexandre.

    1987-01-01

    Bacteriophages are employed as agents for recognition and identification of molecules and cellular materials, using their ability to recognize their bacterial host, by coating them with antibodies or by selecting them to perform in a manner analogous to antibodies. Visibility for identification is effected by incorporating a fluorescent agent, a radioisotope, a metal, an enzyme, or other staining material. The method of this invention may be utilized in selected clinical procedures, and is adaptable to use in an assay kit. (author)

  14. Biochip microsystem for bioinformatics recognition and analysis

    Science.gov (United States)

    Lue, Jaw-Chyng (Inventor); Fang, Wai-Chi (Inventor)

    2011-01-01

    A system with applications in pattern recognition, or classification, of DNA assay samples. Because DNA reference and sample material in wells of an assay may be caused to fluoresce depending upon dye added to the material, the resulting light may be imaged onto an embodiment comprising an array of photodetectors and an adaptive neural network, with applications to DNA analysis. Other embodiments are described and claimed.

  15. Conformational proofreading: the impact of conformational changes on the specificity of molecular recognition.

    Directory of Open Access Journals (Sweden)

    Yonatan Savir

    Full Text Available To perform recognition, molecules must locate and specifically bind their targets within a noisy biochemical environment with many look-alikes. Molecular recognition processes, especially the induced-fit mechanism, are known to involve conformational changes. This raises a basic question: Does molecular recognition gain any advantage by such conformational changes? By introducing a simple statistical-mechanics approach, we study the effect of conformation and flexibility on the quality of recognition processes. Our model relates specificity to the conformation of the participant molecules and thus suggests a possible answer: Optimal specificity is achieved when the ligand is slightly off target; that is, a conformational mismatch between the ligand and its main target improves the selectivity of the process. This indicates that deformations upon binding serve as a conformational proofreading mechanism, which may be selected for via evolution.

  16. Work and Recognition

    DEFF Research Database (Denmark)

    Willig, Rasmus

    2004-01-01

    individual and collective identity formation and has led to an increase in social pathological illnesses such as stress and depression. By juxtaposing these analyses with Honneth’s theory on recognition, we conclude that the contemporary logic of work is unable to provide adequate forms of recognition......The article deals with the relationship between work and recognition, taking Axel Honneth’s social-philosophical theory of the struggle for recognition as its point of departure. In order to give sociological substance to Honneth’s theory, we turn to three contemporary social theorists - Jean......-Pierre Le Goff, Christophe Dejours and Emmanuel Renault. In spite of many differences, their work is united by a critical description of the logic of work and its consequences for individual individuation. These theorists agree that the growth of autonomy, flexibility and mobility has destabilised...

  17. Forensic speaker recognition

    NARCIS (Netherlands)

    Meuwly, Didier

    2013-01-01

    The aim of forensic speaker recognition is to establish links between individuals and criminal activities, through audio speech recordings. This field is multidisciplinary, combining predominantly phonetics, linguistics, speech signal processing, and forensic statistics. On these bases, expert-based

  18. Heterobifunctional crosslinkers for tethering single ligand molecules to scanning probes

    International Nuclear Information System (INIS)

    Riener, Christian K.; Kienberger, Ferry; Hahn, Christoph D.; Buchinger, Gerhard M.; Egwim, Innocent O.C.; Haselgruebler, Thomas; Ebner, Andreas; Romanin, Christoph; Klampfl, Christian; Lackner, Bernd; Prinz, Heino; Blaas, Dieter; Hinterdorfer, Peter; Gruber, Hermann J.

    2003-01-01

    Single molecule recognition force microscopy (SMRFM) is a versatile atomic force microscopy (AFM) method to probe specific interactions of cognitive molecules on the single molecule level. It allows insights to be gained into interaction potentials and kinetic barriers and is capable of mapping interaction sites with nm positional accuracy. These applications require a ligand to be attached to the AFM tip, preferably by a distensible poly(ethylene glycol) (PEG) chain between the measuring tip and the ligand molecule. The PEG chain greatly facilitates specific binding of the ligand to immobile receptor sites on the sample surface. The present study contributes to tip-PEG-ligand tethering in three ways: (i) a convenient synthetic route was found to prepare NH 2 -PEG-COOH which is the key intermediate for long heterobifunctional crosslinkers; (ii) a variety of heterobifunctional PEG derivatives for tip-PEG-ligand linking were prepared from NH 2 -PEG-COOH; (iii) in particular, a new PEG crosslinker with one thiol-reactive end and one terminal nitrilotriacetic acid (NTA) group was synthesized and successfully used to tether His 6 -tagged protein molecules to AFM tips via noncovalent NTA-Ni 2+ -His 6 bridges. The new crosslinker was applied to link a recombinant His 6 -tagged fragment of the very-low density lipoprotein receptor to the AFM tip whereupon specific docking to the capsid of human rhinovirus particles was observed by force microscopy. In a parallel study, the specific interaction of the small GTPase Ran with the nuclear import receptor importin β1 was studied in detail by SMRFM, using the new crosslinker to link His 6 -tagged Ran to the measuring tip [Nat. Struct. Biol. (2003), 10, 553-557

  19. The Recognition Of Fatigue

    DEFF Research Database (Denmark)

    Elsass, Peter; Jensen, Bodil; Mørup, Rikke

    2007-01-01

    Elsass P., Jensen B., Morup R., Thogersen M.H. (2007). The Recognition Of Fatigue: A qualitative study of life-stories from rehabilitation clients. International Journal of Psychosocial Rehabilitation. 11 (2), 75-87......Elsass P., Jensen B., Morup R., Thogersen M.H. (2007). The Recognition Of Fatigue: A qualitative study of life-stories from rehabilitation clients. International Journal of Psychosocial Rehabilitation. 11 (2), 75-87...

  20. Wood Species Recognition System

    OpenAIRE

    Bremananth R; Nithya B; Saipriya R

    2009-01-01

    The proposed system identifies the species of the wood using the textural features present in its barks. Each species of a wood has its own unique patterns in its bark, which enabled the proposed system to identify it accurately. Automatic wood recognition system has not yet been well established mainly due to lack of research in this area and the difficulty in obtaining the wood database. In our work, a wood recognition system has been designed based on pre-processing te...

  1. Evaluating music emotion recognition

    DEFF Research Database (Denmark)

    Sturm, Bob L.

    2013-01-01

    A fundamental problem with nearly all work in music genre recognition (MGR)is that evaluation lacks validity with respect to the principal goals of MGR. This problem also occurs in the evaluation of music emotion recognition (MER). Standard approaches to evaluation, though easy to implement, do...... not reliably differentiate between recognizing genre or emotion from music, or by virtue of confounding factors in signals (e.g., equalization). We demonstrate such problems for evaluating an MER system, and conclude with recommendations....

  2. Action recognition is sensitive to the identity of the actor.

    Science.gov (United States)

    Ferstl, Ylva; Bülthoff, Heinrich; de la Rosa, Stephan

    2017-09-01

    Recognizing who is carrying out an action is essential for successful human interaction. The cognitive mechanisms underlying this ability are little understood and have been subject of discussions in embodied approaches to action recognition. Here we examine one solution, that visual action recognition processes are at least partly sensitive to the actor's identity. We investigated the dependency between identity information and action related processes by testing the sensitivity of neural action recognition processes to clothing and facial identity information with a behavioral adaptation paradigm. Our results show that action adaptation effects are in fact modulated by both clothing information and the actor's facial identity. The finding demonstrates that neural processes underlying action recognition are sensitive to identity information (including facial identity) and thereby not exclusively tuned to actions. We suggest that such response properties are useful to help humans in knowing who carried out an action. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  3. Why recognition is rational

    Directory of Open Access Journals (Sweden)

    Clintin P. Davis-Stober

    2010-07-01

    Full Text Available The Recognition Heuristic (Gigerenzer and Goldstein, 1996; Goldstein and Gigerenzer, 2002 makes the counter-intuitive prediction that a decision maker utilizing less information may do as well as, or outperform, an idealized decision maker utilizing more information. We lay a theoretical foundation for the use of single-variable heuristics such as the Recognition Heuristic as an optimal decision strategy within a linear modeling framework. We identify conditions under which over-weighting a single predictor is a mini-max strategy among a class of a priori chosen weights based on decision heuristics with respect to a measure of statistical lack of fit we call ``risk''. These strategies, in turn, outperform standard multiple regression as long as the amount of data available is limited. We also show that, under related conditions, weighting only one variable and ignoring all others produces the same risk as ignoring the single variable and weighting all others. This approach has the advantage of generalizing beyond the original environment of the Recognition Heuristic to situations with more than two choice options, binary or continuous representations of recognition, and to other single variable heuristics. We analyze the structure of data used in some prior recognition tasks and find that it matches the sufficient conditions for optimality in our results. Rather than being a poor or adequate substitute for a compensatory model, the Recognition Heuristic closely approximates an optimal strategy when a decision maker has finite data about the world.

  4. Molecular determinants of ligand binding modes in the histamine H(4) receptor: linking ligand-based three-dimensional quantitative structure-activity relationship (3D-QSAR) models to in silico guided receptor mutagenesis studies.

    Science.gov (United States)

    Istyastono, Enade P; Nijmeijer, Saskia; Lim, Herman D; van de Stolpe, Andrea; Roumen, Luc; Kooistra, Albert J; Vischer, Henry F; de Esch, Iwan J P; Leurs, Rob; de Graaf, Chris

    2011-12-08

    The histamine H(4) receptor (H(4)R) is a G protein-coupled receptor (GPCR) that plays an important role in inflammation. Similar to the homologous histamine H(3) receptor (H(3)R), two acidic residues in the H(4)R binding pocket, D(3.32) and E(5.46), act as essential hydrogen bond acceptors of positively ionizable hydrogen bond donors in H(4)R ligands. Given the symmetric distribution of these complementary pharmacophore features in H(4)R and its ligands, different alternative ligand binding mode hypotheses have been proposed. The current study focuses on the elucidation of the molecular determinants of H(4)R-ligand binding modes by combining (3D) quantitative structure-activity relationship (QSAR), protein homology modeling, molecular dynamics simulations, and site-directed mutagenesis studies. We have designed and synthesized a series of clobenpropit (N-(4-chlorobenzyl)-S-[3-(4(5)-imidazolyl)propyl]isothiourea) derivatives to investigate H(4)R-ligand interactions and ligand binding orientations. Interestingly, our studies indicate that clobenpropit (2) itself can bind to H(4)R in two distinct binding modes, while the addition of a cyclohexyl group to the clobenpropit isothiourea moiety allows VUF5228 (5) to adopt only one specific binding mode in the H(4)R binding pocket. Our ligand-steered, experimentally supported protein modeling method gives new insights into ligand recognition by H(4)R and can be used as a general approach to elucidate the structure of protein-ligand complexes.

  5. Rosetta Ligand docking with flexible XML protocols.

    Science.gov (United States)

    Lemmon, Gordon; Meiler, Jens

    2012-01-01

    RosettaLigand is premiere software for predicting how a protein and a small molecule interact. Benchmark studies demonstrate that 70% of the top scoring RosettaLigand predicted interfaces are within 2Å RMSD from the crystal structure [1]. The latest release of Rosetta ligand software includes many new features, such as (1) docking of multiple ligands simultaneously, (2) representing ligands as fragments for greater flexibility, (3) redesign of the interface during docking, and (4) an XML script based interface that gives the user full control of the ligand docking protocol.

  6. EMG Pattern Recognition based on Evidence Accumulation for Prosthesis Control

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.P. [Daewoo Electronics Co., Ltd., Seoul (Korea, Republic of); Park, S.H. [Yonsei University, Seoul (Korea, Republic of)

    1997-12-01

    We present a method of electromyography(EMG) pattern recognition to identify motion commands for the control of a prosthetic arm by evidence accumulation with multiple parameters. Integral absolute value, variance, autoregressive(AR) model coefficients, linear cepstrum coefficients, and adaptive cepstrum vector are extracted as feature parameters from several time segments of the EMG signals. Pattern recognition is carried out through the evidence accumulation procedure using the distances measured with reference parameters. A fuzzy mapping function is designed to transform the distances for the application of the evidence accumulation method. Results are presented to support the feasibility of the suggested approach for EMG pattern recognition. (author). 29 refs., 11 figs., 7 tabs.

  7. Page Recognition: Quantum Leap In Recognition Technology

    Science.gov (United States)

    Miller, Larry

    1989-07-01

    No milestone has proven as elusive as the always-approaching "year of the LAN," but the "year of the scanner" might claim the silver medal. Desktop scanners have been around almost as long as personal computers. And everyone thinks they are used for obvious desktop-publishing and business tasks like scanning business documents, magazine articles and other pages, and translating those words into files your computer understands. But, until now, the reality fell far short of the promise. Because it's true that scanners deliver an accurate image of the page to your computer, but the software to recognize this text has been woefully disappointing. Old optical-character recognition (OCR) software recognized such a limited range of pages as to be virtually useless to real users. (For example, one OCR vendor specified 12-point Courier font from an IBM Selectric typewriter: the same font in 10-point, or from a Diablo printer, was unrecognizable!) Computer dealers have told me the chasm between OCR expectations and reality is so broad and deep that nine out of ten prospects leave their stores in disgust when they learn the limitations. And this is a very important, very unfortunate gap. Because the promise of recognition -- what people want it to do -- carries with it tremendous improvements in our productivity and ability to get tons of written documents into our computers where we can do real work with it. The good news is that a revolutionary new development effort has led to the new technology of "page recognition," which actually does deliver the promise we've always wanted from OCR. I'm sure every reader appreciates the breakthrough represented by the laser printer and page-makeup software, a combination so powerful it created new reasons for buying a computer. A similar breakthrough is happening right now in page recognition: the Macintosh (and, I must admit, other personal computers) equipped with a moderately priced scanner and OmniPage software (from Caere

  8. Use of digital speech recognition in diagnostics radiology

    International Nuclear Information System (INIS)

    Arndt, H.; Stockheim, D.; Mutze, S.; Petersein, J.; Gregor, P.; Hamm, B.

    1999-01-01

    Purpose: Applicability and benefits of digital speech recognition in diagnostic radiology were tested using the speech recognition system SP 6000. Methods: The speech recognition system SP 6000 was integrated into the network of the institute and connected to the existing Radiological Information System (RIS). Three subjects used this system for writing 2305 findings from dictation. After the recognition process the date, length of dictation, time required for checking/correction, kind of examination and error rate were recorded for every dictation. With the same subjects, a correlation was performed with 625 conventionally written finding. Results: After an 1-hour initial training the average error rates were 8.4 to 13.3%. The first adaptation of the speech recognition system (after nine days) decreased the average error rates to 2.4 to 10.7% due to the ability of the program to learn. The 2 nd and 3 rd adaptations resulted only in small changes of the error rate. An individual comparison of the error rate developments in the same kind of investigation showed the relative independence of the error rate on the individual user. Conclusion: The results show that the speech recognition system SP 6000 can be evaluated as an advantageous alternative for quickly recording radiological findings. A comparison between manually writing and dictating the findings verifies the individual differences of the writing speeds and shows the advantage of the application of voice recognition when faced with normal keyboard performance. (orig.) [de

  9. THERMODYNAMIC ASSESSMENT OF ANIONIC LIGANDS ...

    African Journals Online (AJOL)

    DJFLEX

    2010-06-30

    Jun 30, 2010 ... The presence of the ligands (ethylenediaminettraacetic acid, EDTA, enthylenediamine, en,and chloride ion, Cl-) generally improved the sorption capacity for the adsorbent, the best being. Cl- at optimum pH of 2.0 (for Co2+) and 5.0 (for Ni2+ and Cd2+). The thermodynamic studies reveal that the adsorption.

  10. Sampling protein motion and solvent effect during ligand binding

    Science.gov (United States)

    Limongelli, Vittorio; Marinelli, Luciana; Cosconati, Sandro; La Motta, Concettina; Sartini, Stefania; Mugnaini, Laura; Da Settimo, Federico; Novellino, Ettore; Parrinello, Michele

    2012-01-01

    An exhaustive description of the molecular recognition mechanism between a ligand and its biological target is of great value because it provides the opportunity for an exogenous control of the related process. Very often this aim can be pursued using high resolution structures of the complex in combination with inexpensive computational protocols such as docking algorithms. Unfortunately, in many other cases a number of factors, like protein flexibility or solvent effects, increase the degree of complexity of ligand/protein interaction and these standard techniques are no longer sufficient to describe the binding event. We have experienced and tested these limits in the present study in which we have developed and revealed the mechanism of binding of a new series of potent inhibitors of Adenosine Deaminase. We have first performed a large number of docking calculations, which unfortunately failed to yield reliable results due to the dynamical character of the enzyme and the complex role of the solvent. Thus, we have stepped up the computational strategy using a protocol based on metadynamics. Our approach has allowed dealing with protein motion and solvation during ligand binding and finally identifying the lowest energy binding modes of the most potent compound of the series, 4-decyl-pyrazolo[1,5-a]pyrimidin-7-one. PMID:22238423

  11. Character Recognition Using Genetically Trained Neural Networks

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, C.; Stantz, K.M.; Trahan, M.W.; Wagner, J.S.

    1998-10-01

    Computationally intelligent recognition of characters and symbols addresses a wide range of applications including foreign language translation and chemical formula identification. The combination of intelligent learning and optimization algorithms with layered neural structures offers powerful techniques for character recognition. These techniques were originally developed by Sandia National Laboratories for pattern and spectral analysis; however, their ability to optimize vast amounts of data make them ideal for character recognition. An adaptation of the Neural Network Designer soflsvare allows the user to create a neural network (NN_) trained by a genetic algorithm (GA) that correctly identifies multiple distinct characters. The initial successfid recognition of standard capital letters can be expanded to include chemical and mathematical symbols and alphabets of foreign languages, especially Arabic and Chinese. The FIN model constructed for this project uses a three layer feed-forward architecture. To facilitate the input of characters and symbols, a graphic user interface (GUI) has been developed to convert the traditional representation of each character or symbol to a bitmap. The 8 x 8 bitmap representations used for these tests are mapped onto the input nodes of the feed-forward neural network (FFNN) in a one-to-one correspondence. The input nodes feed forward into a hidden layer, and the hidden layer feeds into five output nodes correlated to possible character outcomes. During the training period the GA optimizes the weights of the NN until it can successfully recognize distinct characters. Systematic deviations from the base design test the network's range of applicability. Increasing capacity, the number of letters to be recognized, requires a nonlinear increase in the number of hidden layer neurodes. Optimal character recognition performance necessitates a minimum threshold for the number of cases when genetically training the net. And, the

  12. Crystallization of protein–ligand complexes

    International Nuclear Information System (INIS)

    Hassell, Anne M.; An, Gang; Bledsoe, Randy K.; Bynum, Jane M.; Carter, H. Luke III; Deng, Su-Jun J.; Gampe, Robert T.; Grisard, Tamara E.; Madauss, Kevin P.; Nolte, Robert T.; Rocque, Warren J.; Wang, Liping; Weaver, Kurt L.; Williams, Shawn P.; Wisely, G. Bruce; Xu, Robert; Shewchuk, Lisa M.

    2007-01-01

    Methods presented for growing protein–ligand complexes fall into the categories of co-expression of the protein with the ligands of interest, use of the ligands during protein purification, cocrystallization and soaking the ligands into existing crystals. Obtaining diffraction-quality crystals has long been a bottleneck in solving the three-dimensional structures of proteins. Often proteins may be stabilized when they are complexed with a substrate, nucleic acid, cofactor or small molecule. These ligands, on the other hand, have the potential to induce significant conformational changes to the protein and ab initio screening may be required to find a new crystal form. This paper presents an overview of strategies in the following areas for obtaining crystals of protein–ligand complexes: (i) co-expression of the protein with the ligands of interest, (ii) use of the ligands during protein purification, (iii) cocrystallization and (iv) soaks

  13. Scavenger receptors and β-glucan receptors participate in the recognition of yeasts by murine macrophages.

    Science.gov (United States)

    Józefowski, Szczepan; Yang, Zhiping; Marcinkiewicz, Janusz; Kobzik, Lester

    2012-02-01

    Numerous receptors have been implicated in recognition of pathogenic fungi by macrophages, including the β-glucan receptor dectin-1. The role of scavenger receptors (SRs) in anti-fungal immunity is not well characterized. We studied uptake of unopsonized Saccharomycetes cerevisiae (zymosan) and live Candida albicans yeasts as well as zymosan-stimulated H(2)O(2) production in J774 macrophage-like cells and peritoneal exudate macrophages (PEMs). The role of different receptors was assessed with the use of competitive ligands, transfected cells and receptor-deficient macrophages. The uptake of zymosan by untreated J774 cells was mediated approximately half by SRs and half by a β-glucan receptor which was distinct from dectin-1 and not linked to stimulation of H(2)O(2) production. Ligands of β-glucan receptors and of SRs also inhibited uptake of C. albicans by macrophages (J774 cells and PEMs). In macrophages pretreated with a CpG motif-containing oligodeoxynucleotide (CpG-ODN) the relative contribution of SRs to yeast uptake increased and that of β-glucan receptors decreased. Whereas the class A SR MARCO participated in the uptake of both zymosan and C. albicans by CpG-ODN-pretreated, but not untreated macrophages, the related receptor SR-A/CD204 was involved in the uptake of zymosan, but not of C. albicans. The reduction of zymosan-stimulated H(2)O(2) production observed in DS-pretreated J774 cells and in class A SRs-deficient PEMs suggest that class A SRs mediate part of this process. Our results revealed that SRs belong to a redundant system of receptors for yeasts. Binding of yeasts to different receptors in resting versus CpG-ODN-pre-exposed macrophages may differentially affect polarization of adaptive immune responses.

  14. FUNDAMENTALS OF SPEAKER RECOGNITION

    Directory of Open Access Journals (Sweden)

    Figen ERTAŞ

    2000-02-01

    Full Text Available The explosive growth of information technology in the last decade has made a considerable impact on the design and construction of systems for human-machine communication, which is becoming increasingly important in many aspects of life. Amongst other speech processing tasks, a great deal of attention has been devoted to developing procedures that identify people from their voices, and the design and construction of speaker recognition systems has been a fascinating enterprise pursued over many decades. This paper introduces speaker recognition in general and discusses its relevant parameters in relation to system performance.

  15. Touchless palmprint recognition systems

    CERN Document Server

    Genovese, Angelo; Scotti, Fabio

    2014-01-01

    This book examines the context, motivation and current status of biometric systems based on the palmprint, with a specific focus on touchless and less-constrained systems. It covers new technologies in this rapidly evolving field and is one of the first comprehensive books on palmprint recognition systems.It discusses the research literature and the most relevant industrial applications of palmprint biometrics, including the low-cost solutions based on webcams. The steps of biometric recognition are described in detail, including acquisition setups, algorithms, and evaluation procedures. Const

  16. -Pincer Ligand Family through Ligand Post-Modification

    KAUST Repository

    Huang, Mei-Hui

    2017-10-02

    A series of air-stable nickel complexes containing triazine-based PN3P-pincer ligands were synthesized and fully characterized. Complex 3 contains a de-aromatized central triazine ring from the deprotonation of one of the N–H arms. With a post-modification strategy, the Me-PN3P*NiCl complex (3) could be converted into a new class of diimine–traizine PN3P-pincer nickel complexes.

  17. Chelating ligands for nanocrystals' surface functionalization

    NARCIS (Netherlands)

    Querner, Claudia; Reiss, Peter; Bleuse, Joël; Pron, Adam

    2004-01-01

    A new family of ligands for the surface functionalization of CdSe nanocrystals is proposed, namely alkyl or aryl derivatives of carbodithioic acids (R-C(S)SH). The main advantages of these new ligands are as follows: they nearly quantitatively exchange the initial surface ligands (TOPO) in very mild

  18. Misattribution, false recognition and the sins of memory.

    Science.gov (United States)

    Schacter, D L; Dodson, C S

    2001-09-29

    Memory is sometimes a troublemaker. Schacter has classified memory's transgressions into seven fundamental 'sins': transience, absent-mindedness, blocking, misattribution, suggestibility, bias and persistence. This paper focuses on one memory sin, misattribution, that is implicated in false or illusory recognition of episodes that never occurred. We present data from cognitive, neuropsychological and neuroimaging studies that illuminate aspects of misattribution and false recognition. We first discuss cognitive research examining possible mechanisms of misattribution associated with false recognition. We also consider ways in which false recognition can be reduced or avoided, focusing in particular on the role of distinctive information. We next turn to neuropsychological research concerning patients with amnesia and Alzheimer's disease that reveals conditions under which such patients are less susceptible to false recognition than are healthy controls, thus providing clues about the brain mechanisms that drive false recognition. We then consider neuroimaging studies concerned with the neural correlates of true and false recognition, examining when the two forms of recognition can and cannot be distinguished on the basis of brain activity. Finally, we argue that even though misattribution and other memory sins are annoying and even dangerous, they can also be viewed as by-products of adaptive features of memory.

  19. A new approach for sclera vein recognition

    Science.gov (United States)

    Thomas, N. L.; Du, Yingzi; Zhou, Zhi

    2010-04-01

    The vein structure in the sclera is stable over time, unique to each person, and well suited for human identification. A few researchers have performed sclera vein pattern recognition and reported promising initial results. Sclera recognition poses several challenges: the vein structure moves and deforms with the movement of the eye; images of sclera patterns are often defocused and/or saturated; and, most importantly, the vein structure in the sclera is multi-layered and has complex non-linear deformation. In this paper, we proposed a new method for sclera recognition: First, we developed a color-based sclera region estimation scheme for sclera segmentation. Second, we designed a Gabor wavelet-based sclera pattern enhancement method, and an adaptive thresholding method to emphasize and binarize the sclera vein patterns. Third, we proposed a line descriptor-based feature extraction, registration, and matching method that is illumination-, scale-, orientation-, and deformation-invariant, and can mitigate the multi-layered deformation effects exhibited in the sclera and tolerate segmentation error. It is empirically verified using the UBIRIS database that the proposed method can perform accurate sclera recognition.

  20. A rough set approach to speech recognition

    Science.gov (United States)

    Zhao, Zhigang

    1992-09-01

    Speech recognition is a very difficult classification problem due to the variations in loudness, speed, and tone of voice. In the last 40 years, many methodologies have been developed to solve this problem, but most lack learning ability and depend fully on the knowledge of human experts. Systems of this kind are hard to develop and difficult to maintain and upgrade. A study was conducted to investigate the feasibility of using a machine learning approach in solving speech recognition problems. The system is based on rough set theory. It first generates a set of decision rules using a set of reference words called training samples, and then uses the decision rules to recognize new words. The main feature of this system is that, under the supervision of human experts, the machine learns and applies knowledge on its own to the designated tasks. The main advantages of this system over a traditional system are its simplicity and adaptiveness, which suggest that it may have significant potential in practical applications of computer speech recognition. Furthermore, the studies presented demonstrate the potential application of rough-set based learning systems in solving other important pattern classification problems, such as character recognition, system fault detection, and trainable robotic control.

  1. Protein-ligand interfaces are polarized: discovery of a strong trend for intermolecular hydrogen bonds to favor donors on the protein side with implications for predicting and designing ligand complexes

    Science.gov (United States)

    Raschka, Sebastian; Wolf, Alex J.; Bemister-Buffington, Joseph; Kuhn, Leslie A.

    2018-02-01

    Understanding how proteins encode ligand specificity is fascinating and similar in importance to deciphering the genetic code. For protein-ligand recognition, the combination of an almost infinite variety of interfacial shapes and patterns of chemical groups makes the problem especially challenging. Here we analyze data across non-homologous proteins in complex with small biological ligands to address observations made in our inhibitor discovery projects: that proteins favor donating H-bonds to ligands and avoid using groups with both H-bond donor and acceptor capacity. The resulting clear and significant chemical group matching preferences elucidate the code for protein-native ligand binding, similar to the dominant patterns found in nucleic acid base-pairing. On average, 90% of the keto and carboxylate oxygens occurring in the biological ligands formed direct H-bonds to the protein. A two-fold preference was found for protein atoms to act as H-bond donors and ligand atoms to act as acceptors, and 76% of all intermolecular H-bonds involved an amine donor. Together, the tight chemical and geometric constraints associated with satisfying donor groups generate a hydrogen-bonding lock that can be matched only by ligands bearing the right acceptor-rich key. Measuring an index of H-bond preference based on the observed chemical trends proved sufficient to predict other protein-ligand complexes and can be used to guide molecular design. The resulting Hbind and Protein Recognition Index software packages are being made available for rigorously defining intermolecular H-bonds and measuring the extent to which H-bonding patterns in a given complex match the preference key.

  2. Galeotti on recognition as inclusion

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2008-01-01

    Anna Elisabetta Galeotti's theory of 'toleration as recognition' has been criticised by Peter Jones for being conceptually incoherent, since liberal toleration presupposes a negative attitude to differences, whereas multicultural recognition requires positive affirmation hereof. The paper spells...... out Galeotti's justification for recognition as a requirement of liberal justice in detail and asks in what sense the policies supported by Galeotti are policies of recognition. It is argued that Jones misrepresents Galeotti's theory, insofar as this sense of recognition actually is compatible...... in respects that need to be filled out in order to secure compatibility with liberalism, and that this may prove problematic. Keywords: liberalism; multiculturalism; recognition; toleration...

  3. Redesigning an FKBP-ligand interface to generate chemical dimerizers with novel specificity.

    Science.gov (United States)

    Clackson, T; Yang, W; Rozamus, L W; Hatada, M; Amara, J F; Rollins, C T; Stevenson, L F; Magari, S R; Wood, S A; Courage, N L; Lu, X; Cerasoli, F; Gilman, M; Holt, D A

    1998-09-01

    FKBP ligand homodimers can be used to activate signaling events inside cells and animals that have been engineered to express fusions between appropriate signaling domains and FKBP. However, use of these dimerizers in vivo is potentially limited by ligand binding to endogenous FKBP. We have designed ligands that bind specifically to a mutated FKBP over the wild-type protein by remodeling an FKBP-ligand interface to introduce a specificity binding pocket. A compound bearing an ethyl substituent in place of a carbonyl group exhibited sub-nanomolar affinity and 1,000-fold selectivity for a mutant FKBP with a compensating truncation of a phenylalanine residue. Structural and functional analysis of the new pocket showed that recognition is surprisingly relaxed, with the modified ligand only partially filling the engineered cavity. We incorporated the specificity pocket into a fusion protein containing FKBP and the intracellular domain of the Fas receptor. Cells expressing this modified chimeric protein potently underwent apoptosis in response to AP1903, a homodimer of the modified ligand, both in culture and when implanted into mice. Remodeled dimerizers such as AP1903 are ideal reagents for controlling the activities of cells that have been modified by gene therapy procedures, without interference from endogenous FKBP.

  4. Composite organization of the cobalamin binding and cubilin recognition sites of intrinsic factor

    DEFF Research Database (Denmark)

    Fedosov, Sergey N; Fedosova, Natalya U; Berglund, Lars

    2005-01-01

    of the ligand. Each isolated fragment of IF was tested for the binding to the specific receptor cubilin in the presence or absence of Cbl. Neither apo nor holo forms of IF(20) and IF(30) were recognized by the receptor. When two fragments were mixed and incubated with Cbl, they associated into a stable complex......; however, efficient retention of the ligand required the presence of both fragments. Detailed schemes of the interaction of Cbl with IF(50) and with IF(30) and IF(20) are presented, where the sequential attachment of Cbl to the IF(20) and IF(30) domains plays the key role in recognition and retention......, IF(30+20).Cbl, which bound to cubilin as well as the noncleaved IF(50).Cbl complex. We suggest that formation of the cubilin recognition site on IF is caused by assembly of two distant domains, which allows the saturated protein to be recognized by the receptor. The obtained parameters for ligand...

  5. Recognition of fractal graphs

    NARCIS (Netherlands)

    Perepelitsa, VA; Sergienko, [No Value; Kochkarov, AM

    1999-01-01

    Definitions of prefractal and fractal graphs are introduced, and they are used to formulate mathematical models in different fields of knowledge. The topicality of fractal-graph recognition from the point of view, of fundamental improvement in the efficiency of the solution of algorithmic problems

  6. Optical Character Recognition.

    Science.gov (United States)

    Converso, L.; Hocek, S.

    1990-01-01

    This paper describes computer-based optical character recognition (OCR) systems, focusing on their components (the computer, the scanner, the OCR, and the output device); how the systems work; and features to consider in selecting a system. A list of 26 questions to ask to evaluate systems for potential purchase is included. (JDD)

  7. Tolerance and recognition

    Directory of Open Access Journals (Sweden)

    Hans Marius Hansteen

    2014-12-01

    Full Text Available Even though “toleration” and “recognition” designate opposing attitudes (to tolerate something, implies a negative stance towards it, whereas recognition seems to imply a positive one, the concepts do not constitute mutually exclusive alternatives. However, “toleration” is often associated with liberal universalism, focusing on individual rights, whereas “recognition” often connotes communitarian perspectives, focusing on relations and identity. This paper argues that toleration may be founded on recognition, and that recognition may imply toleration. In outlining a differentiated understanding of the relationship between toleration and recognition, it seems apt to avoid an all-to-general dichotomy between universalism and particularism or, in other words, to reach beyond the debate between liberalism and communitarianism in political philosophy.The paper takes as its starting point the view that the discussion on toleration and diversity in intercultural communication is one of the contexts where it seems important to get beyond the liberal/communitarian dichotomy. Some basic features of Rainer Forst’s theory of toleration and Axel Honneth’s theory of the struggle for recognition are presented, in order to develop a more substantial understanding of the relationship between the concepts of toleration and recognition. One lesson from Forst is that toleration is a normatively dependent concept, i.e., that it is impossible to deduce principles for toleration and its limits from a theory of toleration as such. A central lesson from Honneth is that recognition – understood as a basic human need – is always conflictual and therefore dynamic.Accordingly, a main point in the paper is that the theory of struggles for and about recognition (where struggles for designates struggles within an established order of recognition, and struggles about designates struggles that challenge established orders of recognition may clarify what

  8. Importance of ECM recognition

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Importance of ECM recognition. Leishmaniasis transmitted by parasite injection into blood during blood meal of insect vector. Parasites home in macrophages of liver and spleen - adhere, penetrate, transform and replicate. Macrophage lysis - attack of neighbouring ...

  9. Facial Expression Recognition

    NARCIS (Netherlands)

    Pantic, Maja; Li, S.; Jain, A.

    2009-01-01

    Facial expression recognition is a process performed by humans or computers, which consists of: 1. Locating faces in the scene (e.g., in an image; this step is also referred to as face detection), 2. Extracting facial features from the detected face region (e.g., detecting the shape of facial

  10. Alternative Affinity Ligands for Immunoglobulins.

    Science.gov (United States)

    Kruljec, Nika; Bratkovič, Tomaž

    2017-08-16

    The demand for recombinant therapeutic antibodies and Fc-fusion proteins is expected to increase in the years to come. Hence, extensive efforts are concentrated on improving the downstream processing. In particular, the development of better-affinity chromatography matrices, supporting robust time- and cost-effective antibody purification, is warranted. With the advances in molecular design and high-throughput screening approaches from chemical and biological combinatorial libraries, novel affinity ligands representing alternatives to bacterial immunoglobulin (Ig)-binding proteins have entered the scene. Here, we review the design, development, and properties of diverse classes of alternative antibody-binding ligands, ranging from engineered versions of Ig-binding proteins, to artificial binding proteins, peptides, aptamers, and synthetic small-molecular-weight compounds. We also provide examples of applications for the novel affinity matrices in chromatography and beyond.

  11. Ligand binding by PDZ domains

    DEFF Research Database (Denmark)

    Chi, Celestine N.; Bach, Anders; Strømgaard, Kristian

    2012-01-01

    The postsynaptic density protein-95/disks large/zonula occludens-1 (PDZ) protein domain family is one of the most common protein-protein interaction modules in mammalian cells, with paralogs present in several hundred human proteins. PDZ domains are found in most cell types, but neuronal proteins...... as pathological conditions have been reviewed recently. In this review, we focus on the molecular details of how PDZ domains bind their protein ligands and their potential as drug targets in this context....

  12. Bitopic Ligands and Metastable Binding Sites

    DEFF Research Database (Denmark)

    Fronik, Philipp; Gaiser, Birgit I; Sejer Pedersen, Daniel

    2017-01-01

    of orthosteric binding sites. Bitopic ligands have been employed to address the selectivity problem by combining (linking) an orthosteric ligand with an allosteric modulator, theoretically leading to high-affinity subtype selective ligands. However, it remains a challenge to identify suitable allosteric binding...... that have been reported to date, this type of bitopic ligands would be composed of two identical pharmacophores. Herein, we outline the concept of bitopic ligands, review metastable binding sites, and discuss their potential as a new source of allosteric binding sites....

  13. Soaking suggests "alternative facts": Only co-crystallization discloses major ligand-induced interface rearrangements of a homodimeric tRNA-binding protein indicating a novel mode-of-inhibition.

    Directory of Open Access Journals (Sweden)

    Frederik Rainer Ehrmann

    Full Text Available For the efficient pathogenesis of Shigella, the causative agent of bacillary dysentery, full functionality of tRNA-guanine transglycosylase (TGT is mandatory. TGT performs post-transcriptional modifications of tRNAs in the anticodon loop taking impact on virulence development. This suggests TGT as a putative target for selective anti-shigellosis drug therapy. Since bacterial TGT is only functional as homodimer, its activity can be inhibited either by blocking its active site or by preventing dimerization. Recently, we discovered that in some crystal structures obtained by soaking the full conformational adaptation most likely induced in solution upon ligand binding is not displayed. Thus, soaked structures may be misleading and suggest irrelevant binding modes. Accordingly, we re-investigated these complexes by co-crystallization. The obtained structures revealed large conformational rearrangements not visible in the soaked complexes. They result from spatial perturbations in the ribose-34/phosphate-35 recognition pocket and, consequently, an extended loop-helix motif required to prevent access of water molecules into the dimer interface loses its geometric integrity. Thermodynamic profiles of ligand binding in solution indicate favorable entropic contributions to complex formation when large conformational adaptations in the dimer interface are involved. Native MS titration experiments reveal the extent to which the homodimer is destabilized in the presence of each inhibitor. Unexpectedly, one ligand causes a complete rearrangement of subunit packing within the homodimer, never observed in any other TGT crystal structure before. Likely, this novel twisted dimer is catalytically inactive and, therefore, suggests that stabilizing this non-productive subunit arrangement may be used as a further strategy for TGT inhibition.

  14. A conserved host and pathogen recognition site on immunoglobulins: structural and functional aspects.

    Science.gov (United States)

    Wines, Bruce D; Trist, Halina M; Farrugia, William; Ngo, Chloe; Trowsdale, John; Areschoug, Thomas; Lindahl, Gunnar; Fraser, John D; Ramsland, Paul A

    2012-01-01

    A common site in the constant region (Fc) of immunoglobulins is recognized by host receptors and is a frequent target of proteins expressed by pathogens. This site is located at the junction of two constant domains in the antibody heavy chains and produces a large shallow cavity formed by loops of the CH2 and CH3 domains in IgG and IgA (CH3 and CH4 domains in IgM). Crystal structures have been determined for complexes of IgG-Fc and IgA-Fc with a structurally diverse set of host, pathogen and in vitro selected ligands. While pathogen proteins may directly block interactions with the immunoglobulins thereby evading host immunity, it is likely that the same pathogen molecules also interact with other host factors to carry out their primary biological function. Herein we review the structural and functional aspects of host and pathogen molecular recognition of the common site on the Fc of immunoglobulins. We also propose that some pathogen proteins may promote virulence by affecting the bridging between innate and adaptive immunity.

  15. The application of the neural network on Morse code recognition for users with physical impairments.

    Science.gov (United States)

    Yang, C H; Yang, C H; Chuang, L Y; Truong, T K

    2001-01-01

    Morse code is a simple, speedy and low cost means of communication composed of a series of dots, dashes and space intervals. Each tone element (either a dot, dash or space interval) is transmitted by sending a signal for a defined length of time. This poses a challenge as the automatic recognition of Morse code is dependent upon maintaining a stable typing rate. In this paper, a suitable adaptive automatic recognition method, combining the least-mean-square (LMS) algorithm with a neural network, was applied to this problem. The method presented in this paper is divided into five modules: space recognition, tone recognition, learning process, adaptive processing and character recognition. Statistical analyses demonstrated that the proposed method elicited a better recognition rate in comparison with other methods in the literature.

  16. Speech recognition employing biologically plausible receptive fields

    DEFF Research Database (Denmark)

    Fereczkowski, Michal; Bothe, Hans-Heinrich

    2011-01-01

    The main idea of the project is to build a widely speaker-independent, biologically motivated automatic speech recognition (ASR) system. The two main differences between our approach and current state-of-the-art ASRs are that i) the features used here are based on the responses of neuronlike...... Model-based adaptation procedures. Two databases are used, TI46 for discrete speech a subset of the TIMIT database collected from speakers belonging to the New York dialect region. Each of the selection of 10 sentences is uttered once by each of 35 speakers. The major differences between the two data...... sets initiate the development and comparison of two distinct ASRs within the project, which will be presented in the following. Employing a reduced sampling frequency and bandwidth of the signals, the ASR algorithm reaches and goes beyond recognition results that are known from humans....

  17. Radioiodinated ligands for dopamine receptors

    International Nuclear Information System (INIS)

    Kung, H.F.

    1994-01-01

    The dopamine receptor system is important for normal brain function; it is also the apparent action site for various neuroleptic drugs for the treatment of schizophrenia and other metal disorders. In the past few years radioiodinated ligands for single photon emission tomography (SPECT) have been successfully developed and tested in humans: [ 123 I]TISCH for D1 dopamine receptors; [ 123 I]IBZM, epidepride, IBF and FIDA2, four iodobenzamide derivatives, for D2/D3 dopamine receptors. In addition, [ 123 I]β-CIT (RTI-55) and IPT, cocaine derivatives, for the dopamine reuptake site are potentially useful for diagnosis of loss of dopamine neurons. The first iodinated ligand, (R)trans-7-OH-PIPAT, for D3 dopamine receptors, was synthesized and characterized with cloned cell lines (Spodoptera frugiperda, Sf9) expressing the D2 and D3 dopamine receptors and with rat basal forebrain membrane preparations. Most of the known iodobenzamides displayed similar potency in binding to both D2 and D3 dopamine receptors expressed in the cell lines. Initial studies appear to suggest that by fine tuning the structures it may be possible to develop agents specific for D2 and D3 dopamine receptors. It is important to investigate D2/D3 selectivity for this series of potent ligands

  18. Tumor targeting via integrin ligands

    Directory of Open Access Journals (Sweden)

    Udaya Kiran eMarelli

    2013-08-01

    Full Text Available Selective and targeted delivery of drugs to tumors is a major challenge for an effective cancer therapy and also to overcome the side effects associated with current treatments. Overexpression of various receptors on tumor cells is a characteristic structural and biochemical aspect of tumors and distinguishes them from physiologically normal cells. This abnormal feature is therefore suitable for selectively directing anticancer molecules to tumors by using ligands that can preferentially recognize such receptors. Several subtypes of integrin receptors that are crucial for cell adhesion, cell signaling, cell viability and motility have been shown to have an upregulated expression on cancer cells. Thus, ligands that recognize specific integrin subtypes represent excellent candidates to be conjugated to drugs or drug carrier systems and be targeted to tumors. In this regard, integrins recognizing the RGD cell adhesive sequence have been extensively targeted for tumor specific drug delivery. Here we review key recent examples on the presentation of RGD-based integrin ligands by means of distinct drug delivery systems, and discuss the prospects of such therapies to specifically target tumor cells.

  19. Complex adaptive systems ecology

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2003-01-01

    In the following, I will analyze two articles called Complex Adaptive Systems EcologyI & II (Molin & Molin, 1997 & 2000). The CASE-articles are some of the more quirkyarticles that have come out of the Molecular Microbial Ecology Group - a groupwhere I am currently making observational studies....... They are the result of acooperation between Søren Molin, professor in the group, and his brother, JanMolin, professor at Department of Organization and Industrial Sociology atCopenhagen Business School. The cooperation arises from the recognition that bothmicrobial ecology and sociology/organization theory works...

  20. School IPM Recognition and Certification

    Science.gov (United States)

    Schools and school districts can get support and recognition for implementation of school IPM. EPA is developing a program to provide recognition for school districts that are working towards or have achieved a level of success with school IPM programs.

  1. Computational Approaches to the Chemical Equilibrium Constant in Protein-ligand Binding.

    Science.gov (United States)

    Montalvo-Acosta, Joel José; Cecchini, Marco

    2016-12-01

    The physiological role played by protein-ligand recognition has motivated the development of several computational approaches to the ligand binding affinity. Some of them, termed rigorous, have a strong theoretical foundation but involve too much computation to be generally useful. Some others alleviate the computational burden by introducing strong approximations and/or empirical calibrations, which also limit their general use. Most importantly, there is no straightforward correlation between the predictive power and the level of approximation introduced. Here, we present a general framework for the quantitative interpretation of protein-ligand binding based on statistical mechanics. Within this framework, we re-derive self-consistently the fundamental equations of some popular approaches to the binding constant and pinpoint the inherent approximations. Our analysis represents a first step towards the development of variants with optimum accuracy/efficiency ratio for each stage of the drug discovery pipeline. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  3. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    Artificial Intelligence 17(1): 41–62. Hu M K 1962 Visual pattern recognition by moment invariants. IRE Trans. on Information Theory, IT-8,. 179–187. Huang F T, Zhou Z, Zhang H-J and Chen T 2000 Pose invariant face recognition, Proc. Fourth IEEE. International Conference on Automatic Face and Gesture Recognition, ...

  4. Forensic Face Recognition: A Survey

    NARCIS (Netherlands)

    Ali, Tauseef; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; Quaglia, Adamo; Epifano, Calogera M.

    2012-01-01

    The improvements of automatic face recognition during the last 2 decades have disclosed new applications like border control and camera surveillance. A new application field is forensic face recognition. Traditionally, face recognition by human experts has been used in forensics, but now there is a

  5. Visual Recognition Memory across Contexts

    Science.gov (United States)

    Jones, Emily J. H.; Pascalis, Olivier; Eacott, Madeline J.; Herbert, Jane S.

    2011-01-01

    In two experiments, we investigated the development of representational flexibility in visual recognition memory during infancy using the Visual Paired Comparison (VPC) task. In Experiment 1, 6- and 9-month-old infants exhibited recognition when familiarization and test occurred in the same room, but showed no evidence of recognition when…

  6. Pattern Recognition Receptors in Innate Immunity, Host Defense, and Immunopathology

    Science.gov (United States)

    Suresh, Rahul; Mosser, David M.

    2013-01-01

    Infection by pathogenic microbes initiates a set of complex interactions between the pathogen and the host mediated by pattern recognition receptors. Innate immune responses play direct roles in host defense during the early stages of infection, and they also exert a profound influence on the generation of the adaptive immune responses that ensue.…

  7. Use of pattern recognition methods for nuclear reactor surveillance

    International Nuclear Information System (INIS)

    Dubuisson, B.; Lavison, P.

    1979-01-01

    The principles of pattern recognition are recalled. During the past several years, a team of the University of Compiegne has been working to adapt this method to surveillance of technologically complex systems poblems. In the second part of this article, the previous groundwork study, done in collaboration with CEN-Cadarache, on the surveillance problem of the Rapsodie reactor is described [fr

  8. iNKT Cells and Their potential Lipid Ligands during Viral Infection

    Directory of Open Access Journals (Sweden)

    Anunya eOpasawatchai

    2015-07-01

    Full Text Available Invariant natural killer T (iNKT cells are a unique population of lipid reactive CD1d restricted innate-like T lymphocytes. Despite being a minor population, they serve as an early source of cytokines and promote immunological crosstalk thus bridging innate and adaptive immunity. Diseases ranging from allergy, autoimmunity, and cancer as well as infectious diseases, including viral infection, have been reported to be influenced by iNKT cells. However, it remains unclear how iNKT cells are activated during viral infection, as virus derived lipid antigens have not been reported. Cytokines may activate iNKT cells during infections from influenza and murine cytomegalovirus (MCMV, although CD1d dependent activation is evident in other viral infections. Several viruses, such as dengue virus (DENV, induce CD1d upregulation which correlates with iNKT cell activation. In contrast, Herpes simplex virus type 1 (HSV-1, Human immunodeficiency virus (HIV, Epstein-Barr virus (EBV and Human papiloma virus (HPV promote CD1d downregulation as a strategy to evade iNKT cell recognition. These observations suggest the participation of a CD1d-dependent process in the activation of iNKT cells in response to viral infection. Endogenous lipid ligands, including phospholipids as well as glycosphingolipids, such as glucosylceramide have been proposed to mediate iNKT cell activation. Pro-inflammatory signals produced during viral infection may stimulate iNKT cells through enhanced CD1d dependent endogenous lipid presentation. Furthermore, viral infection may alter lipid composition and inhibit endogenous lipid degradation. Recent advances in this field are reviewed.

  9. Finger vein recognition based on finger crease location

    Science.gov (United States)

    Lu, Zhiying; Ding, Shumeng; Yin, Jing

    2016-07-01

    Finger vein recognition technology has significant advantages over other methods in terms of accuracy, uniqueness, and stability, and it has wide promising applications in the field of biometric recognition. We propose using finger creases to locate and extract an object region. Then we use linear fitting to overcome the problem of finger rotation in the plane. The method of modular adaptive histogram equalization (MAHE) is presented to enhance image contrast and reduce computational cost. To extract the finger vein features, we use a fusion method, which can obtain clear and distinguishable vein patterns under different conditions. We used the Hausdorff average distance algorithm to examine the recognition performance of the system. The experimental results demonstrate that MAHE can better balance the recognition accuracy and the expenditure of time compared with three other methods. Our resulting equal error rate throughout the total procedure was 3.268% in a database of 153 finger vein images.

  10. Applications of evolutionary computation in image processing and pattern recognition

    CERN Document Server

    Cuevas, Erik; Perez-Cisneros, Marco

    2016-01-01

    This book presents the use of efficient Evolutionary Computation (EC) algorithms for solving diverse real-world image processing and pattern recognition problems. It provides an overview of the different aspects of evolutionary methods in order to enable the reader in reaching a global understanding of the field and, in conducting studies on specific evolutionary techniques that are related to applications in image processing and pattern recognition. It explains the basic ideas of the proposed applications in a way that can also be understood by readers outside of the field. Image processing and pattern recognition practitioners who are not evolutionary computation researchers will appreciate the discussed techniques beyond simple theoretical tools since they have been adapted to solve significant problems that commonly arise on such areas. On the other hand, members of the evolutionary computation community can learn the way in which image processing and pattern recognition problems can be translated into an...

  11. Pattern recognition in calorimeters

    International Nuclear Information System (INIS)

    Della Negra, M.

    1980-07-01

    It is probable that LEP detectors will often include 4π calorimeters. Since this is a novel technique, not much expertise exists yet in the field of pattern recognition for large calorimeter systems. A fast method to simulate calorimeter signals, based on an analytical parametrization of electromagnetic and hadronic showers, developped by the UAl software group on calorimetry, is presented. Some reconstruction problems are discussed, in particular the question of disentangling individual showers within an energetic jet

  12. Harmonization versus Mutual Recognition

    DEFF Research Database (Denmark)

    Jørgensen, Jan Guldager; Schröder, Philipp

    with the opportunity to start export sales. In contrast, harmonization, in particular the prospect that one’s own national (but not the foreign) standard becomes the only globally accepted standard, opens the foreign market without balancing entry at home. We study these scenarios in a reduced form lobby game with two......, harmonized standards may fail to harvest the full pro-competitive effects from trade liberalization compared to mutual recognition; moreover, the issue is most pronounced in markets featuring price competition....

  13. Multiple Levels of Recognition in Ants: A Feature of Complex Societies

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia

    2008-01-01

    Communication and recognition are essential for social life. Social insects are good model systems to study social behavior and complexity because their societies are evolutionarily stable and ecologically successful. Ants, in particular, show a large variety of adaptations and are extremely...... diverse. In ants, social interactions are regulated by at least three levels of recognition. Nestmate recognition occurs between colonies, is very effective, and involves fast processing. Within a colony, division of labor is enhanced by recognition of different classes of individuals. Ultimately......, in particular circumstances, such as cooperative colony founding with stable dominance hierarchies, ants are capable of individual recognition. The underlying recognition cues and mechanisms appear to be specific to each recognition level, and their integrated understanding could contribute...

  14. Object Recognition using Feature- and Color-Based Methods

    Science.gov (United States)

    Duong, Tuan; Duong, Vu; Stubberud, Allen

    2008-01-01

    An improved adaptive method of processing image data in an artificial neural network has been developed to enable automated, real-time recognition of possibly moving objects under changing (including suddenly changing) conditions of illumination and perspective. The method involves a combination of two prior object-recognition methods one based on adaptive detection of shape features and one based on adaptive color segmentation to enable recognition in situations in which either prior method by itself may be inadequate. The chosen prior feature-based method is known as adaptive principal-component analysis (APCA); the chosen prior color-based method is known as adaptive color segmentation (ACOSE). These methods are made to interact with each other in a closed-loop system to obtain an optimal solution of the object-recognition problem in a dynamic environment. One of the results of the interaction is to increase, beyond what would otherwise be possible, the accuracy of the determination of a region of interest (containing an object that one seeks to recognize) within an image. Another result is to provide a minimized adaptive step that can be used to update the results obtained by the two component methods when changes of color and apparent shape occur. The net effect is to enable the neural network to update its recognition output and improve its recognition capability via an adaptive learning sequence. In principle, the improved method could readily be implemented in integrated circuitry to make a compact, low-power, real-time object-recognition system. It has been proposed to demonstrate the feasibility of such a system by integrating a 256-by-256 active-pixel sensor with APCA, ACOSE, and neural processing circuitry on a single chip. It has been estimated that such a system on a chip would have a volume no larger than a few cubic centimeters, could operate at a rate as high as 1,000 frames per second, and would consume in the order of milliwatts of power.

  15. Pattern Recognition Control Design

    Science.gov (United States)

    Gambone, Elisabeth A.

    2018-01-01

    Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

  16. Unvoiced Speech Recognition Using Tissue-Conductive Acoustic Sensor

    Directory of Open Access Journals (Sweden)

    Heracleous Panikos

    2007-01-01

    Full Text Available We present the use of stethoscope and silicon NAM (nonaudible murmur microphones in automatic speech recognition. NAM microphones are special acoustic sensors, which are attached behind the talker's ear and can capture not only normal (audible speech, but also very quietly uttered speech (nonaudible murmur. As a result, NAM microphones can be applied in automatic speech recognition systems when privacy is desired in human-machine communication. Moreover, NAM microphones show robustness against noise and they might be used in special systems (speech recognition, speech transform, etc. for sound-impaired people. Using adaptation techniques and a small amount of training data, we achieved for a 20 k dictation task a word accuracy for nonaudible murmur recognition in a clean environment. In this paper, we also investigate nonaudible murmur recognition in noisy environments and the effect of the Lombard reflex on nonaudible murmur recognition. We also propose three methods to integrate audible speech and nonaudible murmur recognition using a stethoscope NAM microphone with very promising results.

  17. Superpixel-Based Feature for Aerial Image Scene Recognition

    Directory of Open Access Journals (Sweden)

    Hongguang Li

    2018-01-01

    Full Text Available Image scene recognition is a core technology for many aerial remote sensing applications. Different landforms are inputted as different scenes in aerial imaging, and all landform information is regarded as valuable for aerial image scene recognition. However, the conventional features of the Bag-of-Words model are designed using local points or other related information and thus are unable to fully describe landform areas. This limitation cannot be ignored when the aim is to ensure accurate aerial scene recognition. A novel superpixel-based feature is proposed in this study to characterize aerial image scenes. Then, based on the proposed feature, a scene recognition method of the Bag-of-Words model for aerial imaging is designed. The proposed superpixel-based feature that utilizes landform information establishes top-task superpixel extraction of landforms to bottom-task expression of feature vectors. This characterization technique comprises the following steps: simple linear iterative clustering based superpixel segmentation, adaptive filter bank construction, Lie group-based feature quantification, and visual saliency model-based feature weighting. Experiments of image scene recognition are carried out using real image data captured by an unmanned aerial vehicle (UAV. The recognition accuracy of the proposed superpixel-based feature is 95.1%, which is higher than those of scene recognition algorithms based on other local features.

  18. Visual Recognition System for Cleaning Tasks by Humanoid Robots

    Directory of Open Access Journals (Sweden)

    Muhammad Attamimi

    2013-11-01

    Full Text Available In this study, we present a visual recognition system that enables a robot to clean a tabletop. The proposed system comprises object recognition, material recognition and ungraspable object detection using information acquired from a visual sensor. Multiple cues such as colour, texture and three-dimensional point-clouds are incorporated adaptively for achieving object recognition. Moreover, near-infrared (NIR reflection intensities captured by the visual sensor are used for realizing material recognition. The Gaussian mixture model (GMM is employed for modelling the tabletop surface that is used for detecting ungraspable objects. The proposed system was implemented in a humanoid robot, and tasks such as object and material recognition were performed in various environments. In addition, we evaluated ungraspable object detection using various objects such as dust, grains and paper waste. Finally, we executed the cleaning task to evaluate the proposed system's performance. The results revealed that the proposed system affords high recognition rates and enables humanoid robots to perform domestic service tasks such as cleaning.

  19. Audio-visual gender recognition

    Science.gov (United States)

    Liu, Ming; Xu, Xun; Huang, Thomas S.

    2007-11-01

    Combining different modalities for pattern recognition task is a very promising field. Basically, human always fuse information from different modalities to recognize object and perform inference, etc. Audio-Visual gender recognition is one of the most common task in human social communication. Human can identify the gender by facial appearance, by speech and also by body gait. Indeed, human gender recognition is a multi-modal data acquisition and processing procedure. However, computational multimodal gender recognition has not been extensively investigated in the literature. In this paper, speech and facial image are fused to perform a mutli-modal gender recognition for exploring the improvement of combining different modalities.

  20. Towards Adaptive Spoken Dialog Systems

    CERN Document Server

    Schmitt, Alexander

    2013-01-01

    In Monitoring Adaptive Spoken Dialog Systems, authors Alexander Schmitt and Wolfgang Minker investigate statistical approaches that allow for recognition of negative dialog patterns in Spoken Dialog Systems (SDS). The presented stochastic methods allow a flexible, portable and  accurate use.  Beginning with the foundations of machine learning and pattern recognition, this monograph examines how frequently users show negative emotions in spoken dialog systems and develop novel approaches to speech-based emotion recognition using hybrid approach to model emotions. The authors make use of statistical methods based on acoustic, linguistic and contextual features to examine the relationship between the interaction flow and the occurrence of emotions using non-acted  recordings several thousand real users from commercial and non-commercial SDS. Additionally, the authors present novel statistical methods that spot problems within a dialog based on interaction patterns. The approaches enable future SDS to offer m...

  1. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial lighting ceases...

  2. QUEST Hierarchy for Hyperspectral Face Recognition

    Directory of Open Access Journals (Sweden)

    David M. Ryer

    2012-01-01

    Full Text Available A qualia exploitation of sensor technology (QUEST motivated architecture using algorithm fusion and adaptive feedback loops for face recognition for hyperspectral imagery (HSI is presented. QUEST seeks to develop a general purpose computational intelligence system that captures the beneficial engineering aspects of qualia-based solutions. Qualia-based approaches are constructed from subjective representations and have the ability to detect, distinguish, and characterize entities in the environment Adaptive feedback loops are implemented that enhance performance by reducing candidate subjects in the gallery and by injecting additional probe images during the matching process. The architecture presented provides a framework for exploring more advanced integration strategies beyond those presented. Algorithmic results and performance improvements are presented as spatial, spectral, and temporal effects are utilized; additionally, a Matlab-based graphical user interface (GUI is developed to aid processing, track performance, and to display results.

  3. Ligand photo-isomerization triggers conformational changes in iGluR2 ligand binding domain.

    Directory of Open Access Journals (Sweden)

    Tino Wolter

    Full Text Available Neurological glutamate receptors bind a variety of artificial ligands, both agonistic and antagonistic, in addition to glutamate. Studying their small molecule binding properties increases our understanding of the central nervous system and a variety of associated pathologies. The large, oligomeric multidomain membrane protein contains a large and flexible ligand binding domains which undergoes large conformational changes upon binding different ligands. A recent application of glutamate receptors is their activation or inhibition via photo-switchable ligands, making them key systems in the emerging field of optochemical genetics. In this work, we present a theoretical study on the binding mode and complex stability of a novel photo-switchable ligand, ATA-3, which reversibly binds to glutamate receptors ligand binding domains (LBDs. We propose two possible binding modes for this ligand based on flexible ligand docking calculations and show one of them to be analogues to the binding mode of a similar ligand, 2-BnTetAMPA. In long MD simulations, it was observed that transitions between both binding poses involve breaking and reforming the T686-E402 protein hydrogen bond. Simulating the ligand photo-isomerization process shows that the two possible configurations of the ligand azo-group have markedly different complex stabilities and equilibrium binding modes. A strong but slow protein response is observed after ligand configuration changes. This provides a microscopic foundation for the observed difference in ligand activity upon light-switching.

  4. Ruthenium Cumulenylidene Complexes Bearing Heteroscorpionate Ligands

    OpenAIRE

    Strinitz, Frank

    2014-01-01

    In previous work of the BURZLAFF group, the design of suitable N,N,O ligands for a wide variety of applications ranging from catalysis to bioinorganic model compounds has been extensively investigated. Especially the methyl substituted bis(3,5-dimethylpyrazol-1-yl) acetate (bdmpza) ligand has shown manifold chemistry, comparable to the anionic cyclopentadienyl (Cp) and hydridotris(pyrazol-1-yl)borato (Tp) ligand. In the first part of this thesis the new tricarbonylmanganese(I) complexes be...

  5. A look at ligand binding thermodynamics in drug discovery.

    Science.gov (United States)

    Claveria-Gimeno, Rafael; Vega, Sonia; Abian, Olga; Velazquez-Campoy, Adrian

    2017-04-01

    Drug discovery is a challenging endeavor requiring the interplay of many different research areas. Gathering information on ligand binding thermodynamics may help considerably in reducing the risk within a high uncertainty scenario, allowing early rejection of flawed compounds and pushing forward optimal candidates. In particular, the free energy, the enthalpy, and the entropy of binding provide fundamental information on the intermolecular forces driving such interaction. Areas covered: The authors review the current status and recent developments in the application of ligand binding thermodynamics in drug discovery. The thermodynamic binding profile (Gibbs energy, enthalpy, and entropy of binding) can be used for lead selection and optimization (binding enthalpy, selectivity, and adaptability). Expert opinion: Binding thermodynamics provides fundamental information on the forces driving the formation of the drug-target complex. It has been widely accepted that binding thermodynamics may be used as a decision criterion along the ligand optimization process in drug discovery and development. In particular, the binding enthalpy may be used as a guide when selecting and optimizing compounds over a set of potential candidates. However, this has been recently called into question by arguing certain difficulties and in the light of certain experimental examples.

  6. Development of immobilized ligands for actinide separations

    International Nuclear Information System (INIS)

    Paine, R.T.

    1994-01-01

    Primary goals during this grant period were to (1) synthesize new bifunctional chelating ligands, (2) characterize the structural features of the Ln and An coordination complexes formed by these ligands, (3) use structural data to iteratively design new classes of multifunctional ligands, and (4) explore additional routes for attachment of key ligands to solid supports that could be useful for chromatographic separations. Some highlights of recently published work as well as a summary of submitted, unpublished and/or still in progress research are outlined

  7. Killer immunoglobulin-like receptor (KIR) and KIR-ligand genotype do not correlate with clinical outcome of renal cell carcinoma patients receiving high-dose IL2.

    Science.gov (United States)

    Wang, Wei; Erbe, Amy K; Gallenberger, Mikayla; Kim, KyungMann; Carmichael, Lakeesha; Hess, Dustin; Mendonca, Eneida A; Song, Yiqiang; Hank, Jacquelyn A; Cheng, Su-Chun; Signoretti, Sabina; Atkins, Michael; Carlson, Alexander; Weiss, Jonathan M; Mier, James; Panka, David; McDermott, David F; Sondel, Paul M

    2016-12-01

    NK cells play a role in many cancer immunotherapies. NK cell activity is tightly regulated by killer immunoglobulin-like receptor (KIR) and KIR-ligand interactions. Inhibitory KIR-ligands have been identified as HLA molecules, while activating KIR-ligands are largely unknown. Individuals that have not inherited the corresponding KIR-ligand for at least one inhibitory KIR gene are termed the "KIR-ligand missing" genotype, and they are thought to have a subset of NK cells that express inhibitory KIRs for which the corresponding KIR-ligand is missing on autologous tissue, and thus will not be inhibited through KIR-ligand recognition. In some settings where an anticancer immunotherapeutic effect is likely mediated by NK cells, individuals with a KIR-ligand missing genotype have shown improved clinical outcome compared to individuals with an "all KIR-ligands present" genotype. In addition, patients receiving hematopoietic stem cell transplants for leukemia may do better if their donor has more activating KIR genes (i.e., KIR haplotype-B). In a recent multi-institution clinical trial of patients with metastatic renal cell carcinoma receiving high-dose IL2 (HD-IL2), 25 % of patients showed a complete or partial tumor response to this therapy. We genotyped KIR and KIR-ligand genes for these patients (n = 107) and tested whether KIR/KIR-ligand genotypes correlated with patient clinical outcomes. In these analyses, we did not find any significant association of KIR/KIR-ligand genotype (either KIR-ligand missing or the presence of KIR haplotype-B) with patient outcome in response to the HD-IL2 therapy.

  8. Gait Recognition Based on Outermost Contour

    Directory of Open Access Journals (Sweden)

    Lili Liu

    2011-10-01

    Full Text Available Gait recognition aims to identify people by the way they walk. In this paper, a simple but e ective gait recognition method based on Outermost Contour is proposed. For each gait image sequence, an adaptive silhouette extraction algorithm is firstly used to segment the frames of the sequence and a series of postprocessing is applied to obtain the normalized silhouette images with less noise. Then a novel feature extraction method based on Outermost Contour is performed. Principal Component Analysis (PCA is adopted to reduce the dimensionality of the distance signals derived from the Outermost Contours of silhouette images. Then Multiple Discriminant Analysis (MDA is used to optimize the separability of gait features belonging to di erent classes. Nearest Neighbor (NN classifier and Nearest Neighbor classifier with respect to class Exemplars (ENN are used to classify the final feature vectors produced by MDA. In order to verify the e ectiveness and robustness of our feature extraction algorithm, we also use two other classifiers: Backpropagation Neural Network (BPNN and Support Vector Machine (SVM for recognition. Experimental results on a gait database of 100 people show that the accuracy of using MDA, BPNN and SVM can achieve 97.67%, 94.33% and 94.67%, respectively.

  9. Development and evaluation of a generic evolutionary method for protein-ligand docking.

    Science.gov (United States)

    Yang, Jinn-Moon

    2004-04-30

    We have developed a generic evolutionary method with an empirical scoring function for the protein-ligand docking, which is a problem of paramount importance in structure-based drug design. This approach, referred to as the GEMDOCK (Generic Evolutionary Method for molecular DOCKing), combines both continuous and discrete search mechanisms. We tested our approach on seven protein-ligand complexes, and the docked lowest energy structures have root-mean-square derivations ranging from 0.32 to 0.99 A with respect to the corresponding crystal ligand structures. In addition, we evaluated GEMDOCK on crossdocking experiments, in which some complexes with an identical protein used for docking all crystallized ligands of these complexes. GEMDOCK yielded 98% docked structures with RMSD below 2.0 A when the ligands were docked into foreign protein structures. We have reported the validation and analysis of our approach on various search spaces and scoring functions. Experimental results show that our approach is robust, and the empirical scoring function is simple and fast to recognize compounds. We found that if GEMDOCK used the RMSD scoring function, then the prediction accuracy was 100% and the docked structures had RMSD below 0.1 A for each test system. These results suggest that GEMDOCK is a useful tool, and may systematically improve the forms and parameters of a scoring function, which is one of major bottlenecks for molecular recognition. Copyright 2004 Wiley Periodicals, Inc. J Comput Chem 25: 843-857, 2004

  10. Re-thinking employee recognition: understanding employee experiences of recognition

    OpenAIRE

    Smith, Charlotte

    2013-01-01

    Despite widespread acceptance of the importance of employee recognition for both individuals and organisations and evidence of its increasing use in organisations, employee recognition has received relatively little focused attention from academic researchers. Particularly lacking is research exploring the lived experience of employee recognition and the interpretations and meanings which individuals give to these experiences. Drawing on qualitative interviews conducted as part of my PhD rese...

  11. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... the investigations of lighting scenarios carried out in two test installations: White Cube and White Box. The test installations are discussed as large-scale experiential instruments. In these test installations we examine what could potentially occur when light using LED technology is integrated and distributed...

  12. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    International Nuclear Information System (INIS)

    Arnold, John

    2015-01-01

    The uranyl cation (UO 2 2+ ) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  13. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, John [Univ. of California, Berkeley, CA (United States)

    2015-01-21

    The uranyl cation (UO₂²⁺) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  14. ADAPT Dataset

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Diagnostics and Prognostics Testbed (ADAPT) Project Lead: Scott Poll Subject Fault diagnosis in electrical power systems Description The Advanced...

  15. Human activity recognition and prediction

    CERN Document Server

    2016-01-01

    This book provides a unique view of human activity recognition, especially fine-grained human activity structure learning, human-interaction recognition, RGB-D data based action recognition, temporal decomposition, and causality learning in unconstrained human activity videos. The techniques discussed give readers tools that provide a significant improvement over existing methodologies of video content understanding by taking advantage of activity recognition. It links multiple popular research fields in computer vision, machine learning, human-centered computing, human-computer interaction, image classification, and pattern recognition. In addition, the book includes several key chapters covering multiple emerging topics in the field. Contributed by top experts and practitioners, the chapters present key topics from different angles and blend both methodology and application, composing a solid overview of the human activity recognition techniques. .

  16. ALGORITHM OF OBJECT RECOGNITION

    Directory of Open Access Journals (Sweden)

    Loktev Alexey Alexeevich

    2012-10-01

    Full Text Available The second important problem to be resolved to the algorithm and its software, that comprises an automatic design of a complex closed circuit television system, represents object recognition, by virtue of which an image is transmitted by the video camera. Since imaging of almost any object is dependent on many factors, including its orientation in respect of the camera, lighting conditions, parameters of the registering system, static and dynamic parameters of the object itself, it is quite difficult to formalize the image and represent it in the form of a certain mathematical model. Therefore, methods of computer-aided visualization depend substantially on the problems to be solved. They can be rarely generalized. The majority of these methods are non-linear; therefore, there is a need to increase the computing power and complexity of algorithms to be able to process the image. This paper covers the research of visual object recognition and implementation of the algorithm in the view of the software application that operates in the real-time mode

  17. Xerostomia: recognition and management.

    Science.gov (United States)

    Fox, Philip C

    2008-01-01

    Awareness and recognition of xerostomia are essential in order to help patients minimize dryness symptoms, to institute preventive measures and to limit oral complications. The dental professional has the opportunity to ask every patient if they are experiencing dry mouth. In particular, complaints of dryness while eating, or difficulty swallowing dry foods, or the necessity of using liquids to ease swallowing are important clues that salivary function may be impaired. As part of a routine oral examination, one should examine the oral cavity carefully for signs of salivary gland dysfunction. Findings such as an increase in caries activity, mucosal alterations, infection or salivary gland enlargement may indicate salivary dysfunction. Evaluation should be conducted proactively at each patient visit. Early recognition will minimize damage and dysfunction and allow appropriate management to begin. Although the salivary dysfunction may be irreversible, preventive measures and conservative treatments can avoid or limit mucosal breakdown, infections and permanent damage to teeth. Adequate symptomatic relief is possible with local palliative and systemic measures in many patients. Appropriate management of symptoms and increasing saliva output may help patients feel more comfortable and improve their quality of life.

  18. Complex Event Recognition Architecture

    Science.gov (United States)

    Fitzgerald, William A.; Firby, R. James

    2009-01-01

    Complex Event Recognition Architecture (CERA) is the name of a computational architecture, and software that implements the architecture, for recognizing complex event patterns that may be spread across multiple streams of input data. One of the main components of CERA is an intuitive event pattern language that simplifies what would otherwise be the complex, difficult tasks of creating logical descriptions of combinations of temporal events and defining rules for combining information from different sources over time. In this language, recognition patterns are defined in simple, declarative statements that combine point events from given input streams with those from other streams, using conjunction, disjunction, and negation. Patterns can be built on one another recursively to describe very rich, temporally extended combinations of events. Thereafter, a run-time matching algorithm in CERA efficiently matches these patterns against input data and signals when patterns are recognized. CERA can be used to monitor complex systems and to signal operators or initiate corrective actions when anomalous conditions are recognized. CERA can be run as a stand-alone monitoring system, or it can be integrated into a larger system to automatically trigger responses to changing environments or problematic situations.

  19. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  20. Macrocyclic ligands for uranium complexation

    Energy Technology Data Exchange (ETDEWEB)

    Potts, K.T.

    1991-04-01

    A highly preorganized 24-macrocycle containing biuret, thiobiuret and pyridine subunits has been prepared by high dilution ring-closure procedures. Intermediate products to this macrocycle have been utilized to extend this synthetic route to include further representatives where solubility and stability will be influenced by substituent variation. A 1:1 complex has been formed from uranyl acetate and a quinquepyridine derivative, this representing a new type of ligand for the uranyl ion. A very convenient synthetic procedure that will allow the incorporation of these macrocycles into polymeric systems has been developed for the introduction of a vinyl substituent into the 4-position of the pyridine ring. Using triflate, vinyltributyltin and Pd{sup 0} chemistry, this procedure should make a variety of substituted 4-vinylpyridines available for the first time. 3 refs.

  1. Macrocyclic ligands for uranium complexation

    International Nuclear Information System (INIS)

    Potts, K.T.

    1991-04-01

    A highly preorganized 24-macrocycle containing biuret, thiobiuret and pyridine subunits has been prepared by high dilution ring-closure procedures. Intermediate products to this macrocycle have been utilized to extend this synthetic route to include further representatives where solubility and stability will be influenced by substituent variation. A 1:1 complex has been formed from uranyl acetate and a quinquepyridine derivative, this representing a new type of ligand for the uranyl ion. A very convenient synthetic procedure that will allow the incorporation of these macrocycles into polymeric systems has been developed for the introduction of a vinyl substituent into the 4-position of the pyridine ring. Using triflate, vinyltributyltin and Pd 0 chemistry, this procedure should make a variety of substituted 4-vinylpyridines available for the first time. 3 refs

  2. Dusting the sugar fingerprint: C-type lectin signaling in adaptive immunity

    NARCIS (Netherlands)

    den Dunnen, Jeroen; Gringhuis, Sonja I.; Geijtenbeek, Teunis B. H.

    2010-01-01

    Pathogen recognition by dendritic cells (DCs) is central to the induction of adaptive immunity. Pattern recognition receptors (PRRs) on DCs interact with pathogens, leading to signaling events that dictate adaptive immune responses. It is becoming clear that C-type lectins are important PRRs that

  3. Markov Models for Handwriting Recognition

    CERN Document Server

    Plotz, Thomas

    2011-01-01

    Since their first inception, automatic reading systems have evolved substantially, yet the recognition of handwriting remains an open research problem due to its substantial variation in appearance. With the introduction of Markovian models to the field, a promising modeling and recognition paradigm was established for automatic handwriting recognition. However, no standard procedures for building Markov model-based recognizers have yet been established. This text provides a comprehensive overview of the application of Markov models in the field of handwriting recognition, covering both hidden

  4. Speech Recognition on Mobile Devices

    DEFF Research Database (Denmark)

    Tan, Zheng-Hua; Lindberg, Børge

    2010-01-01

    The enthusiasm of deploying automatic speech recognition (ASR) on mobile devices is driven both by remarkable advances in ASR technology and by the demand for efficient user interfaces on such devices as mobile phones and personal digital assistants (PDAs). This chapter presents an overview of ASR...... in the mobile context covering motivations, challenges, fundamental techniques and applications. Three ASR architectures are introduced: embedded speech recognition, distributed speech recognition and network speech recognition. Their pros and cons and implementation issues are discussed. Applications within...... command and control, text entry and search are presented with an emphasis on mobile text entry....

  5. Sudden Event Recognition: A Survey

    Directory of Open Access Journals (Sweden)

    Mohd Asyraf Zulkifley

    2013-08-01

    Full Text Available Event recognition is one of the most active research areas in video surveillance fields. Advancement in event recognition systems mainly aims to provide convenience, safety and an efficient lifestyle for humanity. A precise, accurate and robust approach is necessary to enable event recognition systems to respond to sudden changes in various uncontrolled environments, such as the case of an emergency, physical threat and a fire or bomb alert. The performance of sudden event recognition systems depends heavily on the accuracy of low level processing, like detection, recognition, tracking and machine learning algorithms. This survey aims to detect and characterize a sudden event, which is a subset of an abnormal event in several video surveillance applications. This paper discusses the following in detail: (1 the importance of a sudden event over a general anomalous event; (2 frameworks used in sudden event recognition; (3 the requirements and comparative studies of a sudden event recognition system and (4 various decision-making approaches for sudden event recognition. The advantages and drawbacks of using 3D images from multiple cameras for real-time application are also discussed. The paper concludes with suggestions for future research directions in sudden event recognition.

  6. Molecular Mechanisms of Odor Recognition

    National Research Council Canada - National Science Library

    Anholt, Robert

    2000-01-01

    .... We characterized the transduction pathway for the recognition of pheromones in the vomeronasal organ and also characterized subpopulations of olfactory neurons expressing different axonal G proteins...

  7. Sudden Event Recognition: A Survey

    Science.gov (United States)

    Suriani, Nor Surayahani; Hussain, Aini; Zulkifley, Mohd Asyraf

    2013-01-01

    Event recognition is one of the most active research areas in video surveillance fields. Advancement in event recognition systems mainly aims to provide convenience, safety and an efficient lifestyle for humanity. A precise, accurate and robust approach is necessary to enable event recognition systems to respond to sudden changes in various uncontrolled environments, such as the case of an emergency, physical threat and a fire or bomb alert. The performance of sudden event recognition systems depends heavily on the accuracy of low level processing, like detection, recognition, tracking and machine learning algorithms. This survey aims to detect and characterize a sudden event, which is a subset of an abnormal event in several video surveillance applications. This paper discusses the following in detail: (1) the importance of a sudden event over a general anomalous event; (2) frameworks used in sudden event recognition; (3) the requirements and comparative studies of a sudden event recognition system and (4) various decision-making approaches for sudden event recognition. The advantages and drawbacks of using 3D images from multiple cameras for real-time application are also discussed. The paper concludes with suggestions for future research directions in sudden event recognition. PMID:23921828

  8. Ligand based pharmacophore modelling of anticancer histone ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... HDAC ligands (Chen et al., 2008b). The knowledge of common properties of the binding group is essential for the determination of the type of inhibitor binding the target. Major goal of modern drug design is identification and development of new ligands with high affinity of binding toward a given protein.

  9. Organometallic chemistry of chiral diphosphazane ligands ...

    Indian Academy of Sciences (India)

    Unknown

    1. Introduction. Diphosphazanes constitute a class of versatile short-bite bidentate P-donor ligands that have given rise to a varied and extensive transition metal organometallic chemistry. The organometallic chemistry of diphosphazane ligands with almost every transition metal in the periodic table is well documented1–3.

  10. Cofactor-Controlled Chirality of Tropoisomeric Ligand

    NARCIS (Netherlands)

    Théveau, L.; Bellini, R.; Dydio, P.; Szabo, Z.; van der Werf, A.; Sander, R.A.; Reek, J.N.H.; Moberg, C.

    2016-01-01

    A new tropos ligand with an integrated anion receptor receptor site has been prepared. Chiral carboxylate and phosphate anions that bind in the anion receptor unit proved capable of stabilizing chiral conformations of the achiral flexible bidentate biaryl phosphite ligand, as shown by variable

  11. Ligand modification for mono- and biphasic oxosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Haerter, P.; Herrmann, W.A.; Baskakov, D. [Technische Univ. Muenchen (Germany). Dept. Chemie

    2006-07-01

    The use of aqueous/organic biphasic systems has attracted huge interest in catalytic reactions by transition metal complexes. [1,2,3] The biphasic systems have benefits in catalyst separation and recycling, and the reduction or elimination of organic solvents is also advantageous for the development of economical and environmentally friendly processes. The key for such biphasic catalysis is the use of water soluble phosphines as ligands. Since the launch of the commercial propylene hydroformylation process by Ruhrchemie/Rhone-Poulenc, sulfonated ligands such as TPPTS (1), and BINAS (2) have been widely used as ligands in hydroformylation, hydrogenation and related reactions catalyzed by transition metals. One of the draw backs of ligands 1 and 2 are corrosive production conditions and therefore unfavorable costs. With the synthesis of aminoacid based trishydroxymethylphosphine derivatives (THMP-aminoacid) we introduce to our knowledge a new group of water soluble and cheap to produce ligands [8]. The properties of catalysts based on these compounds in the hydroformylation reaction of propene are discussed in comparison to normally used catalyst systems. In a second part the performance of catalysts containing NHC-ligands in the hydroformylation of 1-octene is discussed [9]. These investigations show, that the activity can be influenced by the electron donating ability of the NHC ligand. Sterical variations on the NHC ligands have no effect on the selectivity performance of the the catalysts. (orig.)

  12. Organometallic chemistry of chiral diphosphazane ligands ...

    Indian Academy of Sciences (India)

    Unknown

    organometallic chemistry of diphosphazane ligands with almost every transition metal in the periodic table is well documented1–3. A very attractive feature of diphosphazane ligands is that 'chirality' can be incorporated at the phosphorus centres as well as at the substituents attached to the nitrogen and the two phosphorus ...

  13. Ligand sphere conversions in terminal carbide complexes

    DEFF Research Database (Denmark)

    Morsing, Thorbjørn Juul; Reinholdt, Anders; Sauer, Stephan P. A.

    2016-01-01

    Metathesis is introduced as a preparative route to terminal carbide complexes. The chloride ligands of the terminal carbide complex [RuC(Cl)2(PCy3)2] (RuC) can be exchanged, paving the way for a systematic variation of the ligand sphere. A series of substituted complexes, including the first exam...

  14. The cingulo-opercular network provides word-recognition benefit.

    Science.gov (United States)

    Vaden, Kenneth I; Kuchinsky, Stefanie E; Cute, Stephanie L; Ahlstrom, Jayne B; Dubno, Judy R; Eckert, Mark A

    2013-11-27

    Recognizing speech in difficult listening conditions requires considerable focus of attention that is often demonstrated by elevated activity in putative attention systems, including the cingulo-opercular network. We tested the prediction that elevated cingulo-opercular activity provides word-recognition benefit on a subsequent trial. Eighteen healthy, normal-hearing adults (10 females; aged 20-38 years) performed word recognition (120 trials) in multi-talker babble at +3 and +10 dB signal-to-noise ratios during a sparse sampling functional magnetic resonance imaging (fMRI) experiment. Blood oxygen level-dependent (BOLD) contrast was elevated in the anterior cingulate cortex, anterior insula, and frontal operculum in response to poorer speech intelligibility and response errors. These brain regions exhibited significantly greater correlated activity during word recognition compared with rest, supporting the premise that word-recognition demands increased the coherence of cingulo-opercular network activity. Consistent with an adaptive control network explanation, general linear mixed model analyses demonstrated that increased magnitude and extent of cingulo-opercular network activity was significantly associated with correct word recognition on subsequent trials. These results indicate that elevated cingulo-opercular network activity is not simply a reflection of poor performance or error but also supports word recognition in difficult listening conditions.

  15. Adaptation Stories

    International Development Research Centre (IDRC) Digital Library (Canada)

    By Reg'

    formed a real foundation for endogenous, and, therefore, sustainable, strategies for adaptation to climate change. The stories reinforce what we already knew: that successful adaptation must come from the people who are living on the front lines, facing the many problems caused by climate change and climate variation.

  16. Monoclonal antibody-assisted structure-function analysis of the carbohydrate recognition domain of surfactant protein D

    DEFF Research Database (Denmark)

    Hartshorn, Kevan L; White, Mitchell R; Rynkiewicz, Michael

    2010-01-01

    Surfactant protein D (SP-D) plays important roles in host defense against a variety of pathogens including influenza A virus (IAV). Ligand binding by SP-D is mediated by the trimeric neck and carbohydrate recognition domain (NCRD). We used monoclonal antibodies (mAbs) against human SP-D and a panel...

  17. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.J. Jr.; Tisone, G.C.

    1994-12-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

  18. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.H. Jr.; Tisone, G.C.

    1994-06-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures, even when the mixture is noisy and contaminated with unknowns.

  19. Iris Recognition Using Wavelet

    Directory of Open Access Journals (Sweden)

    Khaliq Masood

    2013-08-01

    Full Text Available Biometric systems are getting more attention in the present era. Iris recognition is one of the most secure and authentic among the other biometrics and this field demands more authentic, reliable and fast algorithms to implement these biometric systems in real time. In this paper, an efficient localization technique is presented to identify pupil and iris boundaries using histogram of the iris image. Two small portions of iris have been used for polar transformation to reduce computational time and to increase the efficiency of the system. Wavelet transform is used for feature vector generation. Rotation of iris is compensated without shifts in the iris code. System is tested on Multimedia University Iris Database and results show that proposed system has encouraging performance.

  20. SAR: Stroke Authorship Recognition

    KAUST Repository

    Shaheen, Sara

    2015-10-15

    Are simple strokes unique to the artist or designer who renders them? If so, can this idea be used to identify authorship or to classify artistic drawings? Also, could training methods be devised to develop particular styles? To answer these questions, we propose the Stroke Authorship Recognition (SAR) approach, a novel method that distinguishes the authorship of 2D digitized drawings. SAR converts a drawing into a histogram of stroke attributes that is discriminative of authorship. We provide extensive classification experiments on a large variety of data sets, which validate SAR\\'s ability to distinguish unique authorship of artists and designers. We also demonstrate the usefulness of SAR in several applications including the detection of fraudulent sketches, the training and monitoring of artists in learning a particular new style and the first quantitative way to measure the quality of automatic sketch synthesis tools. © 2015 The Eurographics Association and John Wiley & Sons Ltd.

  1. Pattern Recognition Receptors in Cancer Progression and Metastasis

    Directory of Open Access Journals (Sweden)

    Sanjay Pandey

    2015-01-01

    Full Text Available The innate immune system is an integral component of the inflammatory response to pathophysiological stimuli. Toll-like receptors (TLRs and inflammasomes are the major sensors and pattern recognition receptors (PRRs of the innate immune system that activate stimulus (signal-specific proinflammatory responses. Chronic activation of PRRs has been found to be associated with the aggressiveness of various cancers and poor prognosis. Involvement of PRRs was earlier considered to be limited to infection- and injury-driven carcinogenesis, where they are activated by pathogenic ligands. With the recognition of damage-associated molecular patterns (DAMPs as ligands of PRRs, the role of PRRs in carcinogenesis has also been implicated in other non-pathogen-driven neoplasms. Dying (apoptotic or necrotic cells shed a plethora of DAMPs causing persistent activation of PRRs, leading to chronic inflammation and carcinogenesis. Such chronic activation of TLRs promotes tumor cell proliferation and enhances tumor cell invasion and metastasis by regulating pro-inflammatory cytokines, metalloproteinases, and integrins. Due to the decisive role of PRRs in carcinogenesis, targeting PRRs appears to be an effective cancer-preventive strategy. This review provides a brief account on the association of PRRs with various cancers and their role in carcinogenesis.

  2. The Legal Recognition of Sign Languages

    Science.gov (United States)

    De Meulder, Maartje

    2015-01-01

    This article provides an analytical overview of the different types of explicit legal recognition of sign languages. Five categories are distinguished: constitutional recognition, recognition by means of general language legislation, recognition by means of a sign language law or act, recognition by means of a sign language law or act including…

  3. Methods of Teaching Speech Recognition

    Science.gov (United States)

    Rader, Martha H.; Bailey, Glenn A.

    2010-01-01

    Objective: This article introduces the history and development of speech recognition, addresses its role in the business curriculum, outlines related national and state standards, describes instructional strategies, and discusses the assessment of student achievement in speech recognition classes. Methods: Research methods included a synthesis of…

  4. Iris Recognition - Beyond One Meter

    Science.gov (United States)

    Matey, James R.; Kennell, Lauren R.

    Iris recognition Iris recognition is, arguably, the most robust form of biometric Biometrics identification. It has been deployed in large-scale systems that have been very effective. The systems deployed to date make use of iris Remote Biometric cameras that require significant user cooperation; that in turn imposes significant constraints on the deployment scenarios that are practical.

  5. Side-View Face Recognition

    NARCIS (Netherlands)

    Santemiz, P.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; van den Biggelaar, Olivier

    As a widely used biometrics, face recognition has many advantages such as being non-intrusive, natural and passive. On the other hand, in real-life scenarios with uncontrolled environment, pose variation up to side-view positions makes face recognition a challenging work. In this paper we discuss

  6. Forensic Face Recognition: A Survey

    NARCIS (Netherlands)

    Ali, Tauseef; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

    2010-01-01

    Beside a few papers which focus on the forensic aspects of automatic face recognition, there is not much published about it in contrast to the literature on developing new techniques and methodologies for biometric face recognition. In this report, we review forensic facial identification which is

  7. Side-View Face Recognition

    NARCIS (Netherlands)

    Santemiz, P.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2010-01-01

    Side-view face recognition is a challenging problem with many applications. Especially in real-life scenarios where the environment is uncontrolled, coping with pose variations up to side-view positions is an important task for face recognition. In this paper we discuss the use of side view face

  8. Computer image processing and recognition

    Science.gov (United States)

    Hall, E. L.

    1979-01-01

    A systematic introduction to the concepts and techniques of computer image processing and recognition is presented. Consideration is given to such topics as image formation and perception; computer representation of images; image enhancement and restoration; reconstruction from projections; digital television, encoding, and data compression; scene understanding; scene matching and recognition; and processing techniques for linear systems.

  9. Conformational changes and allosteric communications in human serum albumin due to ligand binding.

    Science.gov (United States)

    Ahalawat, Navjeet; Murarka, Rajesh K

    2015-01-01

    It is well recognized that knowledge of structure alone is not sufficient to understand the fundamental mechanism of biomolecular recognition. Information of dynamics is necessary to describe motions involving relevant conformational states of functional importance. We carried out principal component analysis (PCA) of structural ensemble, derived from 84 crystal structures of human serum albumin (HSA) with different ligands and/or different conditions, to identify the functionally important collective motions, and compared with the motions along the low-frequency modes obtained from normal mode analysis of the elastic network model (ENM) of unliganded HSA. Significant overlap is observed in the collective motions derived from PCA and ENM. PCA and ENM analysis revealed that ligand selects the most favored conformation from accessible equilibrium structures of unliganded HSA. Further, we analyzed dynamic network obtained from molecular dynamics simulations of unliganded HSA and fatty acids- bound HSA. Our results show that fatty acids-bound HSA has more robust community network with several routes to communicate among different parts of the protein. Critical nodes (residues) identified from dynamic network analysis are in good agreement with allosteric residues obtained from sequence-based statistical coupling analysis method. This work underscores the importance of intrinsic structural dynamics of proteins in ligand recognition and can be utilized for the development of novel drugs with optimum activity.

  10. Correcting ligands, metabolites, and pathways

    Directory of Open Access Journals (Sweden)

    Vriend Gert

    2006-11-01

    Full Text Available Abstract Background A wide range of research areas in bioinformatics, molecular biology and medicinal chemistry require precise chemical structure information about molecules and reactions, e.g. drug design, ligand docking, metabolic network reconstruction, and systems biology. Most available databases, however, treat chemical structures more as illustrations than as a datafield in its own right. Lack of chemical accuracy impedes progress in the areas mentioned above. We present a database of metabolites called BioMeta that augments the existing pathway databases by explicitly assessing the validity, correctness, and completeness of chemical structure and reaction information. Description The main bulk of the data in BioMeta were obtained from the KEGG Ligand database. We developed a tool for chemical structure validation which assesses the chemical validity and stereochemical completeness of a molecule description. The validation tool was used to examine the compounds in BioMeta, showing that a relatively small number of compounds had an incorrect constitution (connectivity only, not considering stereochemistry and that a considerable number (about one third had incomplete or even incorrect stereochemistry. We made a large effort to correct the errors and to complete the structural descriptions. A total of 1468 structures were corrected and/or completed. We also established the reaction balance of the reactions in BioMeta and corrected 55% of the unbalanced (stoichiometrically incorrect reactions in an automatic procedure. The BioMeta database was implemented in PostgreSQL and provided with a web-based interface. Conclusion We demonstrate that the validation of metabolite structures and reactions is a feasible and worthwhile undertaking, and that the validation results can be used to trigger corrections and improvements to BioMeta, our metabolite database. BioMeta provides some tools for rational drug design, reaction searches, and

  11. CRISPR-Cas: evolution of an RNA-based adaptive immunity system in prokaryotes.

    Science.gov (United States)

    Koonin, Eugene V; Makarova, Kira S

    2013-05-01

    The CRISPR-Cas (clustered regularly interspaced short palindromic repeats, CRISPR-associated genes) is an adaptive immunity system in bacteria and archaea that functions via a distinct self-non-self recognition mechanism that is partially analogous to the mechanism of eukaryotic RNA interference (RNAi). The CRISPR-Cas system incorporates fragments of virus or plasmid DNA into the CRISPR repeat cassettes and employs the processed transcripts of these spacers as guide RNAs to cleave the cognate foreign DNA or RNA. The Cas proteins, however, are not homologous to the proteins involved in RNAi and comprise numerous, highly diverged families. The majority of the Cas proteins contain diverse variants of the RNA recognition motif (RRM), a widespread RNA-binding domain. Despite the fast evolution that is typical of the cas genes, the presence of diverse versions of the RRM in most Cas proteins provides for a simple scenario for the evolution of the three distinct types of CRISPR-cas systems. In addition to several proteins that are directly implicated in the immune response, the cas genes encode a variety of proteins that are homologous to prokaryotic toxins that typically possess nuclease activity. The predicted toxins associated with CRISPR-Cas systems include the essential Cas2 protein, proteins of COG1517 that, in addition to a ligand-binding domain and a helix-turn-helix domain, typically contain different nuclease domains and several other predicted nucleases. The tight association of the CRISPR-Cas immunity systems with predicted toxins that, upon activation, would induce dormancy or cell death suggests that adaptive immunity and dormancy/suicide response are functionally coupled. Such coupling could manifest in the persistence state being induced and potentially providing conditions for more effective action of the immune system or in cell death being triggered when immunity fails.

  12. Autocrine signal transmission with extracellular ligand degradation

    International Nuclear Information System (INIS)

    Muratov, C B; Posta, F; Shvartsman, S Y

    2009-01-01

    Traveling waves of cell signaling in epithelial layers orchestrate a number of important processes in developing and adult tissues. These waves can be mediated by positive feedback autocrine loops, a mode of cell signaling where binding of a diffusible extracellular ligand to a cell surface receptor can lead to further ligand release. We formulate and analyze a biophysical model that accounts for ligand-induced ligand release, extracellular ligand diffusion and ligand–receptor interaction. We focus on the case when the main mode for ligand degradation is extracellular and analyze the problem with the sharp threshold positive feedback nonlinearity. We derive expressions that link the speed of propagation and other characteristics of traveling waves to the parameters of the biophysical processes, such as diffusion rates, receptor expression level, etc. Analyzing the derived expressions we found that traveling waves in such systems can exhibit a number of unusual properties, e.g. non-monotonic dependence of the speed of propagation on ligand diffusivity. Our results for the fully developed traveling fronts can be used to analyze wave initiation from localized perturbations, a scenario that frequently arises in the in vitro models of epithelial wound healing, and guide future modeling studies of cell communication in epithelial layers

  13. Chemistry of marine ligands and siderophores.

    Science.gov (United States)

    Vraspir, Julia M; Butler, Alison

    2009-01-01

    Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cadmium, thus defining the speciation of these metal ions in the ocean. In the case of iron, siderophores have been identified and structurally characterized. Siderophores are low molecular weight iron-binding ligands produced by marine bacteria. Although progress has been made toward the identity of in situ iron-binding ligands, few compounds have been identified that coordinate the other trace metals. Deciphering the chemical structures and production stimuli of naturally produced organic ligands and the organisms they come from is fundamental to understanding metal speciation and bioavailability. The current evidence for marine ligands, with an emphasis on siderophores, and discussion of the importance and implications of metal-binding ligands in controlling metal speciation and cycling within the world's oceans are presented.

  14. Recognition memory impairments caused by false recognition of novel objects.

    Science.gov (United States)

    Yeung, Lok-Kin; Ryan, Jennifer D; Cowell, Rosemary A; Barense, Morgan D

    2013-11-01

    A fundamental assumption underlying most current theories of amnesia is that memory impairments arise because previously studied information either is lost rapidly or is made inaccessible (i.e., the old information appears to be new). Recent studies in rodents have challenged this view, suggesting instead that under conditions of high interference, recognition memory impairments following medial temporal lobe damage arise because novel information appears as though it has been previously seen. Here, we developed a new object recognition memory paradigm that distinguished whether object recognition memory impairments were driven by previously viewed objects being treated as if they were novel or by novel objects falsely recognized as though they were previously seen. In this indirect, eyetracking-based passive viewing task, older adults at risk for mild cognitive impairment showed false recognition to high-interference novel items (with a significant degree of feature overlap with previously studied items) but normal novelty responses to low-interference novel items (with a lower degree of feature overlap). The indirect nature of the task minimized the effects of response bias and other memory-based decision processes, suggesting that these factors cannot solely account for false recognition. These findings support the counterintuitive notion that recognition memory impairments in this memory-impaired population are not characterized by forgetting but rather are driven by the failure to differentiate perceptually similar objects, leading to the false recognition of novel objects as having been seen before. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  15. Radiation induced ligand loss from cobalt complexes

    International Nuclear Information System (INIS)

    Funston, A. M.; McFadyen, W.D.; Tregloan, P.A.

    2000-01-01

    Full text: Due to the rapid nature of ligand dissociation from cobalt(II) complexes the study of the rate of ligand dissociation necessitates the use of a technique such as pulse radiolysis. This allows the rapid reduction of the corresponding cobalt(III) complex by a reducing radical, such as the aquated electron, to form the cobalt(II) complex. However, to date, no systematic study of either the mechanism of reduction or the influence of the electronic structure on the rate of ligand dissociation has been carried out. In order to understand these processes more fully the mechanism of reduction of a range of related cobalt(III) complexes by the aquated electron and the subsequent rate of ligand dissociation from the resulting cobalt(II) complexes is being investigated. It has been found that a number of processes are observed following the initial rapid reaction of the cobalt(III) complex with the aquated electron. Ultimately ligand loss is observed. Depending upon the complex, the initial processes observed may include the formation of coordinated radicals and electron transfer within the complex. For complexes containing aromatic ligands such as 2,2'-bipyridine, 1,10-phenanthroline and dipyrido[3,2-a:2',3'-c]phenazine the formation of a coordinated radical is observed as the initial reduction step. The kinetics of ligand dissociation of these complexes has been determined. The loss of monodentate ligands is fast and has been indistinguishable from the reduction processes when aromatic ligands are also present in the complex. However, for diamine chelates and diimine chelates spectra of the transient species can be resolved

  16. Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells.

    Science.gov (United States)

    Kubota, Ryou; Hamachi, Itaru

    2015-07-07

    Chemical sensing of amino acids, peptides, and proteins provides fruitful information to understand their biological functions, as well as to develop the medical and technological applications. To detect amino acids, peptides, and proteins in vitro and in vivo, vast kinds of chemical sensors including small synthetic binders/sensors, genetically-encoded fluorescent proteins and protein-based semisynthetic biosensors have been intensely investigated. This review deals with concepts, strategies, and applications of protein recognition and sensing using small synthetic binders/sensors, which are now actively studied but still in the early stage of investigation. The recognition strategies for peptides and proteins can be divided into three categories: (i) recognition of protein substructures, (ii) protein surface recognition, and (iii) protein sensing through protein-ligand interaction. Here, we overview representative examples of protein recognition and sensing, and discuss biological or diagnostic applications such as potent inhibitors/modulators of protein-protein interactions.

  17. Siderocalin-mediated recognition, sensitization, and cellular uptake of actinides.

    Science.gov (United States)

    Allred, Benjamin E; Rupert, Peter B; Gauny, Stacey S; An, Dahlia D; Ralston, Corie Y; Sturzbecher-Hoehne, Manuel; Strong, Roland K; Abergel, Rebecca J

    2015-08-18

    Synthetic radionuclides, such as the transuranic actinides plutonium, americium, and curium, present severe health threats as contaminants, and understanding the scope of the biochemical interactions involved in actinide transport is instrumental in managing human contamination. Here we show that siderocalin, a mammalian siderophore-binding protein from the lipocalin family, specifically binds lanthanide and actinide complexes through molecular recognition of the ligands chelating the metal ions. Using crystallography, we structurally characterized the resulting siderocalin-transuranic actinide complexes, providing unprecedented insights into the biological coordination of heavy radioelements. In controlled in vitro assays, we found that intracellular plutonium uptake can occur through siderocalin-mediated endocytosis. We also demonstrated that siderocalin can act as a synergistic antenna to sensitize the luminescence of trivalent lanthanide and actinide ions in ternary protein-ligand complexes, dramatically increasing the brightness and efficiency of intramolecular energy transfer processes that give rise to metal luminescence. Our results identify siderocalin as a potential player in the biological trafficking of f elements, but through a secondary ligand-based metal sequestration mechanism. Beyond elucidating contamination pathways, this work is a starting point for the design of two-stage biomimetic platforms for photoluminescence, separation, and transport applications.

  18. Toothbrush Adaptations.

    Science.gov (United States)

    Exceptional Parent, 1987

    1987-01-01

    Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)

  19. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    2017-01-01

    intense relational mechanisms provide an effective means for contingency adaptation and therefore reduce the probability of premature termination. However, in situations where relationships are already governed by longer duration contracts, we argue that investments in relational mechanism create...

  20. Stabilization of enzyme by using hydrophobic ligands

    Energy Technology Data Exchange (ETDEWEB)

    Ota, H.; Yamahara, K.; Kuboi, R. [Osaka University, Osaka (Japan)

    1998-02-01

    The protection (stabilization) effect of various hydrophobic ligands on the denaturation and aggregation of carbonic anhydrase from bovine (CAB) has been quantitatively investigated under various heat stress conditions. In a limited temperature range (40-60degC), where the protein was only partially denatured and the local hydrophobicities (LH) of CAB were positive effective stabilization of the protein is achieved by the addition of various ligands. The importance of balance between hydrophobic head and hydrophilic tail of the ligands is hypothesized. 18 refs., 5 figs.

  1. A versatile dinucleating ligand containing sulfonamide groups

    DEFF Research Database (Denmark)

    Sundberg, Jonas; Witt, Hannes; Cameron, Lisa

    2014-01-01

    ligand can be prepared in aqueous solutions using only divalent metal ions. Two of the copper(II) complexes, [Cu2(psmp)(OH)] and [Cu2(psmp)(OAc)2]-, demonstrate the anticipated 1:2 ligand/metal stoichiometry and show that the dimetallic binding site created for exogenous ligands possesses high inherent...... of antiferromagnetic coupling. This is corroborated computationally by broken-symmetry density functional theory, which for isotropic modeling of the coupling predicts an antiferromagnetic coupling strength of J = 70.5 cm-1....

  2. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    We investigate why some exchange relationships terminate prematurely. We argue that investments in informal governance structures induce premature termination in relationships already governed by formal contracts. The formalized adaptive behavior of formal governance structures and the flexible...... and reciprocal adaptation of informal governance structure create ambiguity in situations of contingencies, which, subsequently, increases the likelihood of premature relationship termination. Using a large sample of exchange relationships in the global service provider industry, we find support for a hypothesis...

  3. Strategic Adaptation

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    2015-01-01

    This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related...... concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation...

  4. Adaptive ethnography

    DEFF Research Database (Denmark)

    Berth, Mette

    2005-01-01

    This paper focuses on the use of an adaptive ethnography when studying such phenomena as young people's use of mobile media in a learning perspective. Mobile media such as PDAs and mobile phones have a number of affordances which make them potential tools for learning. However, before we begin...... formal and informal learning contexts. The paper also proposes several adaptive methodological techniques for studying young people's interaction with mobiles....

  5. Speech Recognition: How Do We Teach It?

    Science.gov (United States)

    Barksdale, Karl

    2002-01-01

    States that growing use of speech recognition software has made voice writing an essential computer skill. Describes how to present the topic, develop basic speech recognition skills, and teach speech recognition outlining, writing, proofreading, and editing. (Contains 14 references.) (SK)

  6. An HMM-Like Dynamic Time Warping Scheme for Automatic Speech Recognition

    Directory of Open Access Journals (Sweden)

    Ing-Jr Ding

    2014-01-01

    Full Text Available In the past, the kernel of automatic speech recognition (ASR is dynamic time warping (DTW, which is feature-based template matching and belongs to the category technique of dynamic programming (DP. Although DTW is an early developed ASR technique, DTW has been popular in lots of applications. DTW is playing an important role for the known Kinect-based gesture recognition application now. This paper proposed an intelligent speech recognition system using an improved DTW approach for multimedia and home automation services. The improved DTW presented in this work, called HMM-like DTW, is essentially a hidden Markov model- (HMM- like method where the concept of the typical HMM statistical model is brought into the design of DTW. The developed HMM-like DTW method, transforming feature-based DTW recognition into model-based DTW recognition, will be able to behave as the HMM recognition technique and therefore proposed HMM-like DTW with the HMM-like recognition model will have the capability to further perform model adaptation (also known as speaker adaptation. A series of experimental results in home automation-based multimedia access service environments demonstrated the superiority and effectiveness of the developed smart speech recognition system by HMM-like DTW.

  7. Morse code recognition system with fuzzy algorithm for disabled persons.

    Science.gov (United States)

    Wu, C-M; Luo, C-H

    2002-01-01

    It is generally known that Morse code is an efficient input method for one or two switches and it is made from long and short sounds separated by silence between the sounds. The long-to-short ratio in the definition is always 3 to 1, but the long-to-short ratio variation for a disabled person is so large that it is difficult to recognize. In the last few years, several Morse code recognition methods have been successfully built on the LMS adaptive algorithms and neural network algorithm. But LMS-related adaptive algorithms need mass computation to infer the characteristic of the controller; also the neural network must learn first, by inputting some data before it is used to recognize the Morse code sequence. In this study, two fuzzy algorithms are used to recognize the unstable Morse code sequences and the result demonstrates a significant improvement of recognition for real time signal processing in a single-chip microprocessor.

  8. Automatic identification of otological drilling faults: an intelligent recognition algorithm.

    Science.gov (United States)

    Cao, Tianyang; Li, Xisheng; Gao, Zhiqiang; Feng, Guodong; Shen, Peng

    2010-06-01

    This article presents an intelligent recognition algorithm that can recognize milling states of the otological drill by fusing multi-sensor information. An otological drill was modified by the addition of sensors. The algorithm was designed according to features of the milling process and is composed of a characteristic curve, an adaptive filter and a rule base. The characteristic curve can weaken the impact of the unstable normal milling process and reserve the features of drilling faults. The adaptive filter is capable of suppressing interference in the characteristic curve by fusing multi-sensor information. The rule base can identify drilling faults through the filtering result data. The experiments were repeated on fresh porcine scapulas, including normal milling and two drilling faults. The algorithm has high rates of identification. This study shows that the intelligent recognition algorithm can identify drilling faults under interference conditions. (c) 2010 John Wiley & Sons, Ltd.

  9. Is adaptation. Truly an adaptation? Is adaptation. Truly an adaptation?

    Directory of Open Access Journals (Sweden)

    Thais Flores Nogueira Diniz

    2008-04-01

    Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning. The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition

  10. Autonomy, recognition and education

    Directory of Open Access Journals (Sweden)

    Angelo Vitório Cenci

    2015-01-01

    Full Text Available This paper addresses Honneth’s concept of autonomy from two dimensions of his work, distinct, though inseparable. The first one is suggested through the subject’s positive practical self-relation linked to the patterns of reciprocal recognition of love, right and social esteem; the second is formulated as non-centered autonomy opposed to the present-day criticism of the modern autonomous subject encompassing three levels, namely: the capacity of linguistic articulation, the narrative coherence of life and the complementation of being guided by principles with some criteria of moral sensitivity to the context. We defend the position that, by metaphysically anchoring the concept of autonomy onto the intersubjective assumptions of his/her theory of the subject, and exploring it linked to the subject’s positive practical self-relation and to a non-centered meaning, Honneth has managed to renew it, which allows drawing important consequences of such effort to the field of education.

  11. Pattern recognition in spectra

    Science.gov (United States)

    Gebran, M.; Paletou, F.

    2017-06-01

    We present a new automated procedure that simultaneously derives the effective temperature Teff, surface gravity log g, metallicity [Fe/H], and equatorial projected rotational velocity ve sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones.

  12. Pattern recognition in spectra

    International Nuclear Information System (INIS)

    Gebran, M; Paletou, F

    2017-01-01

    We present a new automated procedure that simultaneously derives the effective temperature T eff , surface gravity log g , metallicity [ Fe/H ], and equatorial projected rotational velocity v e sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones. (paper)

  13. Imprecision of adaptation in Escherichia coli chemotaxis.

    Directory of Open Access Journals (Sweden)

    Silke Neumann

    Full Text Available Adaptability is an essential property of many sensory systems, enabling maintenance of a sensitive response over a range of background stimulus levels. In bacterial chemotaxis, adaptation to the preset level of pathway activity is achieved through an integral feedback mechanism based on activity-dependent methylation of chemoreceptors. It has been argued that this architecture ensures precise and robust adaptation regardless of the ambient ligand concentration, making perfect adaptation a celebrated property of the chemotaxis system. However, possible deviations from such ideal adaptive behavior and its consequences for chemotaxis have not been explored in detail. Here we show that the chemotaxis pathway in Escherichia coli shows increasingly imprecise adaptation to higher concentrations of attractants, with a clear correlation between the time of adaptation to a step-like stimulus and the extent of imprecision. Our analysis suggests that this imprecision results from a gradual saturation of receptor methylation sites at high levels of stimulation, which prevents full recovery of the pathway activity by violating the conditions required for precise adaptation. We further use computer simulations to show that limited imprecision of adaptation has little effect on the rate of chemotactic drift of a bacterial population in gradients, but hinders precise accumulation at the peak of the gradient. Finally, we show that for two major chemoeffectors, serine and cysteine, failure of adaptation at concentrations above 1 mM might prevent bacteria from accumulating at toxic concentrations of these amino acids.

  14. Thermodynamic fingerprints of ligand binding to human telomeric G-quadruplexes.

    Science.gov (United States)

    Bončina, Matjaž; Podlipnik, Črtomir; Piantanida, Ivo; Eilmes, Julita; Teulade-Fichou, Marie-Paule; Vesnaver, Gorazd; Lah, Jurij

    2015-12-02

    Thermodynamic studies of ligand binding to human telomere (ht) DNA quadruplexes, as a rule, neglect the involvement of various ht-DNA conformations in the binding process. Therefore, the thermodynamic driving forces and the mechanisms of ht-DNA G-quadruplex-ligand recognition remain poorly understood. In this work we characterize thermodynamically and structurally binding of netropsin (Net), dibenzotetraaza[14]annulene derivatives (DP77, DP78), cationic porphyrin (TMPyP4) and two bisquinolinium ligands (Phen-DC3, 360A-Br) to the ht-DNA fragment (Tel22) AGGG(TTAGGG)3 using isothermal titration calorimetry, CD and fluorescence spectroscopy, gel electrophoresis and molecular modeling. By global thermodynamic analysis of experimental data we show that the driving forces characterized by contributions of specific interactions, changes in solvation and conformation differ significantly for binding of ligands with low quadruplex selectivity over duplexes (Net, DP77, DP78, TMPyP4; KTel22 ≈ KdsDNA). These contributions are in accordance with the observed structural features (changes) and suggest that upon binding Net, DP77, DP78 and TMPyP4 select hybrid-1 and/or hybrid-2 conformation while Phen-DC3 and 360A-Br induce the transition of hybrid-1 and hybrid-2 to the structure with characteristics of antiparallel or hybrid-3 type conformation. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Controlling Signal Transduction with Synthetic Ligands

    Science.gov (United States)

    Spencer, David M.; Wandless, Thomas J.; Schreiber, Stuart L.; Crabtree, Gerald R.

    1993-11-01

    Dimerization and oligomerization are general biological control mechanisms contributing to the activation of cell membrane receptors, transcription factors, vesicle fusion proteins, and other classes of intra- and extracellular proteins. Cell permeable, synthetic ligands were devised that can be used to control the intracellular oligomerization of specific proteins. To demonstrate their utility, these ligands were used to reduce intracellular oligomerization of cell surface receptors that lacked their transmembrane and extracellular regions but contained intracellular signaling domains. Addition of these ligands to cells in culture resulted in signal transmission and specific target gene activation. Monomeric forms of the ligands blocked the pathway. This method of ligandregulated activation and termination of signaling pathways has the potential to be applied wherever precise control of a signal transduction pathway is desired.

  16. Allyl functionalized phosphinite and phosphonite ligands: Synthesis ...

    Indian Academy of Sciences (India)

    Allyl functionalized phosphinite and phosphonite ligands: Synthesis, transition metal chemistry and orthopalladation reactions. SINGAPPAGUDEM GOVINDARAJUa, GUDDEKOPPA S ANANTHNAGa, SUSMITA NAIKa,. SHAIKH M MOBINb and MARAVANJI S BALAKRISHNAa,∗. aPhosphorus Laboratory, Department of ...

  17. Organometallic chemistry of chiral diphosphazane ligands ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 114; Issue 4. Organometallic chemistry of chiral diphosphazane ligands: Synthesis and structural characterisation. Kannan Raghuraman Swadhin K Mandal T S Venkatakrishnan Setharampattu S Krishnamurthy Munirathinam Nethaji. Volume 114 Issue 4 August 2002 ...

  18. EGFR Activation by Spatially Restricted Ligands

    National Research Council Canada - National Science Library

    Clouse, Katherine N; Goodrich, Jennifer S

    2006-01-01

    ...) activity has been associated with an increased prognosis of breast cancer. During cogenesis in Drosophila melanogaster local Egfr activation by the spatially-restricted TGFalpha-like ligand Gurken (Grk...

  19. EGFR Activation by Spatially Restricted Ligands

    National Research Council Canada - National Science Library

    Goodrich, Jennifer S

    2005-01-01

    ...) activity has been associated with an increased prognosis of breast cancer. During oogenesis in Drosophila melanogaster, local EGFR activation by the spatially restricted TGF alpha-like ligand, Gurken (Grk...

  20. Recognition Using Classification and Segmentation Scoring

    National Research Council Canada - National Science Library

    Kimball, Owen; Ostendorf, Mari; Rohlicek, Robin

    1992-01-01

    .... We describe an approach to connected word recognition that allows the use of segmental information through an explicit decomposition of the recognition criterion into classification and segmentation scoring...

  1. Vision-Based Navigation and Recognition

    National Research Council Canada - National Science Library

    Rosenfeld, Azriel

    1996-01-01

    .... (4) Invariants -- both geometric and other types. (5) Human faces: Analysis of images of human faces, including feature extraction, face recognition, compression, and recognition of facial expressions...

  2. Vision-Based Navigation and Recognition

    National Research Council Canada - National Science Library

    Rosenfeld, Azriel

    1998-01-01

    .... (4) Invariants: both geometric and other types. (5) Human faces: Analysis of images of human faces, including feature extraction, face recognition, compression, and recognition of facial expressions...

  3. Kernel learning algorithms for face recognition

    CERN Document Server

    Li, Jun-Bao; Pan, Jeng-Shyang

    2013-01-01

    Kernel Learning Algorithms for Face Recognition covers the framework of kernel based face recognition. This book discusses the advanced kernel learning algorithms and its application on face recognition. This book also focuses on the theoretical deviation, the system framework and experiments involving kernel based face recognition. Included within are algorithms of kernel based face recognition, and also the feasibility of the kernel based face recognition method. This book provides researchers in pattern recognition and machine learning area with advanced face recognition methods and its new

  4. Facial recognition in education system

    Science.gov (United States)

    Krithika, L. B.; Venkatesh, K.; Rathore, S.; Kumar, M. Harish

    2017-11-01

    Human beings exploit emotions comprehensively for conveying messages and their resolution. Emotion detection and face recognition can provide an interface between the individuals and technologies. The most successful applications of recognition analysis are recognition of faces. Many different techniques have been used to recognize the facial expressions and emotion detection handle varying poses. In this paper, we approach an efficient method to recognize the facial expressions to track face points and distances. This can automatically identify observer face movements and face expression in image. This can capture different aspects of emotion and facial expressions.

  5. Iris recognition via plenoptic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J.; Boehnen, Chris Bensing; Bolme, David S.

    2017-11-07

    Iris recognition can be accomplished for a wide variety of eye images by using plenoptic imaging. Using plenoptic technology, it is possible to correct focus after image acquisition. One example technology reconstructs images having different focus depths and stitches them together, resulting in a fully focused image, even in an off-angle gaze scenario. Another example technology determines three-dimensional data for an eye and incorporates it into an eye model used for iris recognition processing. Another example technology detects contact lenses. Application of the technologies can result in improved iris recognition under a wide variety of scenarios.

  6. Evaluating music emotion recognition:Lessons from music genre recognition?

    OpenAIRE

    Sturm, Bob L.

    2013-01-01

    A fundamental problem with nearly all work in music genre recognition (MGR)is that evaluation lacks validity with respect to the principal goals of MGR. This problem also occurs in the evaluation of music emotion recognition (MER). Standard approaches to evaluation, though easy to implement, do not reliably differentiate between recognizing genre or emotion from music, or by virtue of confounding factors in signals (e.g., equalization). We demonstrate such problems for evaluating an MER syste...

  7. Pattern recognition for Space Applications Center director's discretionary fund

    Science.gov (United States)

    Singley, M. E.

    1984-01-01

    Results and conclusions are presented on the application of recent developments in pattern recognition to spacecraft star mapping systems. Sensor data for two representative starfields are processed by an adaptive shape-seeking version of the Fc-V algorithm with good results. Cluster validity measures are evaluated, but not found especially useful to this application. Recommendations are given two system configurations worthy of additional study,

  8. Toxoplasma gondii peptide ligands open the gate of the HLA class I binding groove

    DEFF Research Database (Denmark)

    McMurtrey, Curtis; Trolle, Thomas; Sansom, Tiffany

    2016-01-01

    N-terminal binding core yet exhibit a C-terminal extension of 1-30 amino acids. Structural analysis demonstrates that binding of extended peptides opens the HLA class I F' pocket, allowing the C-terminal extension to protrude through one end of the binding groove. In summary, we demonstrate...... that unrealized structural flexibility makes MHC class I receptive to parasite-derived ligands that exhibit unique C-terminal peptide extensions.......HLA class I presentation of pathogen-derived peptide ligands is essential for CD8+ T cell recognition of Toxoplasma gondii infected cells. Currently, little data exist pertaining to peptides that are presented after T. gondii infection. Herein we purify HLA-A*02:01 complexes from T. gondii infected...

  9. Chemistry of Marine Ligands and Siderophores

    OpenAIRE

    Vraspir, Julia M.; Butler, Alison

    2009-01-01

    Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cad...

  10. Hand Gesture Recognition Using Ultrasonic Waves

    KAUST Repository

    AlSharif, Mohammed Hussain

    2016-04-01

    Gesturing is a natural way of communication between people and is used in our everyday conversations. Hand gesture recognition systems are used in many applications in a wide variety of fields, such as mobile phone applications, smart TVs, video gaming, etc. With the advances in human-computer interaction technology, gesture recognition is becoming an active research area. There are two types of devices to detect gestures; contact based devices and contactless devices. Using ultrasonic waves for determining gestures is one of the ways that is employed in contactless devices. Hand gesture recognition utilizing ultrasonic waves will be the focus of this thesis work. This thesis presents a new method for detecting and classifying a predefined set of hand gestures using a single ultrasonic transmitter and a single ultrasonic receiver. This method uses a linear frequency modulated ultrasonic signal. The ultrasonic signal is designed to meet the project requirements such as the update rate, the range of detection, etc. Also, it needs to overcome hardware limitations such as the limited output power, transmitter, and receiver bandwidth, etc. The method can be adapted to other hardware setups. Gestures are identified based on two main features; range estimation of the moving hand and received signal strength (RSS). These two factors are estimated using two simple methods; channel impulse response (CIR) and cross correlation (CC) of the reflected ultrasonic signal from the gesturing hand. A customized simple hardware setup was used to classify a set of hand gestures with high accuracy. The detection and classification were done using methods of low computational cost. This makes the proposed method to have a great potential for the implementation in many devices including laptops and mobile phones. The predefined set of gestures can be used for many control applications.

  11. The selenium metabolite methylselenol regulates the expression of ligands that trigger immune activation through the lymphocyte receptor NKG2D

    DEFF Research Database (Denmark)

    Hagemann-Jensen, Michael Henrik; Uhlenbrock, Franziska Katharina; Kehlet, Stephanie

    2014-01-01

    For decades Selenium (Se) research has been focused on the identification of active metabolites, which are crucial for Se chemoprevention of cancer. In this context, the metabolite methylselenol (CH3SeH) is known for its action to selectively kill transformed cells through mechanisms that include......: Increased formation of reactive oxygen species (ROS), induction of DNA damage, triggering of apoptosis and the inhibition of angiogenesis. Here, we revealed that CH3SeH modulates cell surface expression of NKG2D ligands. The expression of NKG2D ligands is induced by stress-associated pathways, which occur...... early during malignant transformation, and enables recognition and elimination of tumors by activating the lymphocyte receptor NKG2D. CH3SeH regulated NKG2D ligands both on the transcriptional and the posttranscriptional level: CH3SeH induced the transcription of MICA/B and ULBP2 mRNA, however...

  12. [Early recognition of partial learning disorders].

    Science.gov (United States)

    Esser, G

    1991-01-01

    The long-term outcome of learning disabilities (lower school performance, higher rates of unemployment and unskilled jobs, secondary psychic disorders and juvenile delinquency) requires their early recognition even at pre-school age. The concept of learning disabilities should be adapted to the concept of specific developmental disorders (ICD-10, F80-F83). The diagnosis of specific developmental disorders at pre-school age shows many difficulties due to the drawbacks of the available psychological tests. A highly economic and reliable battery of tests is presented as an alternative, which enables us to diagnose general intelligence and specific developmental disorders. The diagnostic procedure was standardised on 657 children of four and five years of age.

  13. Algorithms for Hardware-Based Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Müller Dietmar

    2004-01-01

    Full Text Available Nonlinear spatial transforms and fuzzy pattern classification with unimodal potential functions are established in signal processing. They have proved to be excellent tools in feature extraction and classification. In this paper, we will present a hardware-accelerated image processing and classification system which is implemented on one field-programmable gate array (FPGA. Nonlinear discrete circular transforms generate a feature vector. The features are analyzed by a fuzzy classifier. This principle can be used for feature extraction, pattern recognition, and classification tasks. Implementation in radix-2 structures is possible, allowing fast calculations with a computational complexity of up to . Furthermore, the pattern separability properties of these transforms are better than those achieved with the well-known method based on the power spectrum of the Fourier Transform, or on several other transforms. Using different signal flow structures, the transforms can be adapted to different image and signal processing applications.

  14. Cascaded automatic target recognition (Cascaded ATR)

    Science.gov (United States)

    Walls, Bradley

    2010-04-01

    The global war on terror has plunged US and coalition forces into a battle space requiring the continuous adaptation of tactics and technologies to cope with an elusive enemy. As a result, technologies that enhance the intelligence, surveillance, and reconnaissance (ISR) mission making the warfighter more effective are experiencing increased interest. In this paper we show how a new generation of smart cameras built around foveated sensing makes possible a powerful ISR technique termed Cascaded ATR. Foveated sensing is an innovative optical concept in which a single aperture captures two distinct fields of view. In Cascaded ATR, foveated sensing is used to provide a coarse resolution, persistent surveillance, wide field of view (WFOV) detector to accomplish detection level perception. At the same time, within the foveated sensor, these detection locations are passed as a cue to a steerable, high fidelity, narrow field of view (NFOV) detector to perform recognition level perception. Two new ISR mission scenarios, utilizing Cascaded ATR, are proposed.

  15. Designer TGFβ superfamily ligands with diversified functionality.

    Directory of Open Access Journals (Sweden)

    George P Allendorph

    Full Text Available Transforming Growth Factor--beta (TGFβ superfamily ligands, including Activins, Growth and Differentiation Factors (GDFs, and Bone Morphogenetic Proteins (BMPs, are excellent targets for protein-based therapeutics because of their pervasiveness in numerous developmental and cellular processes. We developed a strategy termed RASCH (Random Assembly of Segmental Chimera and Heteromer, to engineer chemically-refoldable TGFβ superfamily ligands with unique signaling properties. One of these engineered ligands, AB208, created from Activin-βA and BMP-2 sequences, exhibits the refolding characteristics of BMP-2 while possessing Activin-like signaling attributes. Further, we find several additional ligands, AB204, AB211, and AB215, which initiate the intracellular Smad1-mediated signaling pathways more strongly than BMP-2 but show no sensitivity to the natural BMP antagonist Noggin unlike natural BMP-2. In another design, incorporation of a short N-terminal segment from BMP-2 was sufficient to enable chemical refolding of BMP-9, without which was never produced nor refolded. Our studies show that the RASCH strategy enables us to expand the functional repertoire of TGFβ superfamily ligands through development of novel chimeric TGFβ ligands with diverse biological and clinical values.

  16. Exploiting ligand-protein conjugates to monitor ligand-receptor interactions.

    Directory of Open Access Journals (Sweden)

    Hirohito Haruki

    Full Text Available We introduce three assays for analyzing ligand-receptor interactions based on the specific conjugation of ligands to SNAP-tag fusion proteins. Conjugation of ligands to different SNAP-tag fusions permits the validation of suspected interactions in cell extracts and fixed cells as well as the establishment of high-throughput assays. The different assays allow the analysis of strong and weak interactions. Conversion of ligands into SNAP-tag substrates thus provides access to a powerful toolbox for the analysis of their interactions with proteins.

  17. Li+-ligand binding energies and the effect of ligand fluorination on the binding energies

    Science.gov (United States)

    Bauschlicher, Charles W.

    2018-02-01

    The Li+-ligand binding energies are computed for seven ligands and their perfluoro analogs using Density Functional Theory. The bonding is mostly electrostatic in origin. Thus the size of the binding energy tends to correlate with the ligand dipole moment, however, the charge-induced dipole contribution can be sufficiently large to affect the dipole-binding energy correlation. The perfluoro species are significantly less strongly bound than their parents, because the electron withdrawing power of the fluorine reduces the ligand dipole moment.

  18. LigandRFs: random forest ensemble to identify ligand-binding residues from sequence information alone

    KAUST Repository

    Chen, Peng

    2014-12-03

    Background Protein-ligand binding is important for some proteins to perform their functions. Protein-ligand binding sites are the residues of proteins that physically bind to ligands. Despite of the recent advances in computational prediction for protein-ligand binding sites, the state-of-the-art methods search for similar, known structures of the query and predict the binding sites based on the solved structures. However, such structural information is not commonly available. Results In this paper, we propose a sequence-based approach to identify protein-ligand binding residues. We propose a combination technique to reduce the effects of different sliding residue windows in the process of encoding input feature vectors. Moreover, due to the highly imbalanced samples between the ligand-binding sites and non ligand-binding sites, we construct several balanced data sets, for each of which a random forest (RF)-based classifier is trained. The ensemble of these RF classifiers forms a sequence-based protein-ligand binding site predictor. Conclusions Experimental results on CASP9 and CASP8 data sets demonstrate that our method compares favorably with the state-of-the-art protein-ligand binding site prediction methods.

  19. Iris double recognition based on modified evolutionary neural network

    Science.gov (United States)

    Liu, Shuai; Liu, Yuan-Ning; Zhu, Xiao-Dong; Huo, Guang; Liu, Wen-Tao; Feng, Jia-Kai

    2017-11-01

    Aiming at multicategory iris recognition under illumination and noise interference, this paper proposes a method of iris double recognition based on a modified evolutionary neural network. An equalization histogram and Laplace of Gaussian operator are used to process the iris to suppress illumination and noise interference and Haar wavelet to convert the iris feature to binary feature encoding. Calculate the Hamming distance for the test iris and template iris , and compare with classification threshold, determine the type of iris. If the iris cannot be identified as a different type, there needs to be a secondary recognition. The connection weights in back-propagation (BP) neural network use modified evolutionary neural network to adaptively train. The modified neural network is composed of particle swarm optimization with mutation operator and BP neural network. According to different iris libraries in different circumstances of experimental results, under illumination and noise interference, the correct recognition rate of this algorithm is higher, the ROC curve is closer to the coordinate axis, the training and recognition time is shorter, and the stability and the robustness are better.

  20. Neural Mechanisms and Information Processing in Recognition Systems

    Directory of Open Access Journals (Sweden)

    Mamiko Ozaki

    2014-10-01

    Full Text Available Nestmate recognition is a hallmark of social insects. It is based on the match/mismatch of an identity signal carried by members of the society with that of the perceiving individual. While the behavioral response, amicable or aggressive, is very clear, the neural systems underlying recognition are not fully understood. Here we contrast two alternative hypotheses for the neural mechanisms that are responsible for the perception and information processing in recognition. We focus on recognition via chemical signals, as the common modality in social insects. The first, classical, hypothesis states that upon perception of recognition cues by the sensory system the information is passed as is to the antennal lobes and to higher brain centers where the information is deciphered and compared to a neural template. Match or mismatch information is then transferred to some behavior-generating centers where the appropriate response is elicited. An alternative hypothesis, that of “pre-filter mechanism”, posits that the decision as to whether to pass on the information to the central nervous system takes place in the peripheral sensory system. We suggest that, through sensory adaptation, only alien signals are passed on to the brain, specifically to an “aggressive-behavior-switching center”, where the response is generated if the signal is above a certain threshold.

  1. Synthesis, complexation chemistry and a case of self-recognition of chiral phosphite ligands

    NARCIS (Netherlands)

    Dros, AC; Meetsma, A; Kellogg, RM

    1999-01-01

    Reaction of (R)-(-)-1-phenyl-2,2,3-trimethylbutane-1,3-diol with PCl3 affords trans-(S)-2-chloro-4,4,5,5-tetramethyl-6-(R)-phenyl-1,3,2-dioxaphosphorinane, which couples smoothly with catechol, resorcinol, 2,2-dimethyl-1,3-propanediol and fluorenedimethanol to form the corresponding diphosphites. By

  2. Indoor navigation by image recognition

    Science.gov (United States)

    Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man

    2017-07-01

    With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.

  3. Pattern recognition and string matching

    CERN Document Server

    Cheng, Xiuzhen

    2002-01-01

    The research and development of pattern recognition have proven to be of importance in science, technology, and human activity. Many useful concepts and tools from different disciplines have been employed in pattern recognition. Among them is string matching, which receives much theoretical and practical attention. String matching is also an important topic in combinatorial optimization. This book is devoted to recent advances in pattern recognition and string matching. It consists of twenty eight chapters written by different authors, addressing a broad range of topics such as those from classifica­ tion, matching, mining, feature selection, and applications. Each chapter is self-contained, and presents either novel methodological approaches or applications of existing theories and techniques. The aim, intent, and motivation for publishing this book is to pro­ vide a reference tool for the increasing number of readers who depend upon pattern recognition or string matching in some way. This includes student...

  4. Similarity measures for face recognition

    CERN Document Server

    Vezzetti, Enrico

    2015-01-01

    Face recognition has several applications, including security, such as (authentication and identification of device users and criminal suspects), and in medicine (corrective surgery and diagnosis). Facial recognition programs rely on algorithms that can compare and compute the similarity between two sets of images. This eBook explains some of the similarity measures used in facial recognition systems in a single volume. Readers will learn about various measures including Minkowski distances, Mahalanobis distances, Hansdorff distances, cosine-based distances, among other methods. The book also summarizes errors that may occur in face recognition methods. Computer scientists "facing face" and looking to select and test different methods of computing similarities will benefit from this book. The book is also useful tool for students undertaking computer vision courses.

  5. License plate recognition (phase B).

    Science.gov (United States)

    2010-06-01

    License Plate Recognition (LPR) technology has been used for off-line automobile enforcement purposes. The technology has seen mixed success with correct reading rate as high as 60 to 80% depending on the specific application and environment. This li...

  6. Effective indexing for face recognition

    Science.gov (United States)

    Sochenkov, I.; Sochenkova, A.; Vokhmintsev, A.; Makovetskii, A.; Melnikov, A.

    2016-09-01

    Face recognition is one of the most important tasks in computer vision and pattern recognition. Face recognition is useful for security systems to provide safety. In some situations it is necessary to identify the person among many others. In this case this work presents new approach in data indexing, which provides fast retrieval in big image collections. Data indexing in this research consists of five steps. First, we detect the area containing face, second we align face, and then we detect areas containing eyes and eyebrows, nose, mouth. After that we find key points of each area using different descriptors and finally index these descriptors with help of quantization procedure. The experimental analysis of this method is performed. This paper shows that performing method has results at the level of state-of-the-art face recognition methods, but it is also gives results fast that is important for the systems that provide safety.

  7. Synthesis and characterization of mixed ligand chiral nanoclusters

    KAUST Repository

    Guven, Zekiye P.

    2016-06-22

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

  8. Strategic Adaptation

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    2015-01-01

    concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation......This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related....... This model incorporates elements of central strategizing, autonomous entrepreneurial behavior, interactive information processing, and open communication systems that enhance the organization's ability to observe exogenous changes and respond effectively to them....

  9. Adaptive test

    DEFF Research Database (Denmark)

    Kjeldsen, Lars Peter; Eriksen, Mette Rose

    2010-01-01

    Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale.......Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale....

  10. Language Recognition via Sparse Coding

    Science.gov (United States)

    2016-09-08

    exploiting variation of the nonzero locations and magnitude, we can build a discrimi- native pipeline for language recognition. Figure 1 describes a...classify each language as a target within six predefined language clusters. The language clusters are Ara- bic, Chinese, English , French, Slavic, and... Language Recognition via Sparse Coding† Youngjune L. Gwon1, William M. Campbell1, Douglas Sturim1, H. T. Kung2 1MIT Lincoln Laboratory 2Harvard

  11. An automatic image recognition approach

    Directory of Open Access Journals (Sweden)

    Tudor Barbu

    2007-07-01

    Full Text Available Our paper focuses on the graphical analysis domain. We propose an automatic image recognition technique. This approach consists of two main pattern recognition steps. First, it performs an image feature extraction operation on an input image set, using statistical dispersion features. Then, an unsupervised classification process is performed on the previously obtained graphical feature vectors. An automatic region-growing based clustering procedure is proposed and utilized in the classification stage.

  12. Backpropagation neural networks: pattern recognition

    OpenAIRE

    Studenikin, Oleg

    2005-01-01

    In this Master’s degree work artificial neural networks and back propagation learning algorithm for human faces and pattern recognition are analyzed. In the second part of work artificial neural networks and their architecture and structures models are analyzed. In the third part of article the backpropagation procedure and procedures theoretical learning principle are analyzed. In the fourth part different kinds of ANN methods and patterns extracting methods in recognition, learning and ...

  13. Activity Recognition in Social Media

    Science.gov (United States)

    2015-12-29

    AFRL-AFOSR-JP-TR-2016-0044 Activity Recognition in Social Media Subhasis Chaudhuri INDIAN INSTITUTE OF TECHNOLOGY BOMBAY Final Report 05/09/2016...DATES COVERED (From - To) 12 Aug 2013 to 30 Sep 2015 4. TITLE AND SUBTITLE Activity Recognition in Social Media 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER...15. SUBJECT TERMS Social Media , AOARD, social interactions 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 15 19a

  14. Robust In-Car Speech Recognition Based on Nonlinear Multiple Regressions

    Directory of Open Access Journals (Sweden)

    Itakura Fumitada

    2007-01-01

    Full Text Available We address issues for improving handsfree speech recognition performance in different car environments using a single distant microphone. In this paper, we propose a nonlinear multiple-regression-based enhancement method for in-car speech recognition. In order to develop a data-driven in-car recognition system, we develop an effective algorithm for adapting the regression parameters to different driving conditions. We also devise the model compensation scheme by synthesizing the training data using the optimal regression parameters and by selecting the optimal HMM for the test speech. Based on isolated word recognition experiments conducted in 15 real car environments, the proposed adaptive regression approach shows an advantage in average relative word error rate (WER reductions of 52.5 and 14.8 , compared to original noisy speech and ETSI advanced front end, respectively.

  15. Voice congruency facilitates word recognition.

    Science.gov (United States)

    Campeanu, Sandra; Craik, Fergus I M; Alain, Claude

    2013-01-01

    Behavioral studies of spoken word memory have shown that context congruency facilitates both word and source recognition, though the level at which context exerts its influence remains equivocal. We measured event-related potentials (ERPs) while participants performed both types of recognition task with words spoken in four voices. Two voice parameters (i.e., gender and accent) varied between speakers, with the possibility that none, one or two of these parameters was congruent between study and test. Results indicated that reinstating the study voice at test facilitated both word and source recognition, compared to similar or no context congruency at test. Behavioral effects were paralleled by two ERP modulations. First, in the word recognition test, the left parietal old/new effect showed a positive deflection reflective of context congruency between study and test words. Namely, the same speaker condition provided the most positive deflection of all correctly identified old words. In the source recognition test, a right frontal positivity was found for the same speaker condition compared to the different speaker conditions, regardless of response success. Taken together, the results of this study suggest that the benefit of context congruency is reflected behaviorally and in ERP modulations traditionally associated with recognition memory.

  16. Voice congruency facilitates word recognition.

    Directory of Open Access Journals (Sweden)

    Sandra Campeanu

    Full Text Available Behavioral studies of spoken word memory have shown that context congruency facilitates both word and source recognition, though the level at which context exerts its influence remains equivocal. We measured event-related potentials (ERPs while participants performed both types of recognition task with words spoken in four voices. Two voice parameters (i.e., gender and accent varied between speakers, with the possibility that none, one or two of these parameters was congruent between study and test. Results indicated that reinstating the study voice at test facilitated both word and source recognition, compared to similar or no context congruency at test. Behavioral effects were paralleled by two ERP modulations. First, in the word recognition test, the left parietal old/new effect showed a positive deflection reflective of context congruency between study and test words. Namely, the same speaker condition provided the most positive deflection of all correctly identified old words. In the source recognition test, a right frontal positivity was found for the same speaker condition compared to the different speaker conditions, regardless of response success. Taken together, the results of this study suggest that the benefit of context congruency is reflected behaviorally and in ERP modulations traditionally associated with recognition memory.

  17. Impact of protein and ligand impurities on ITC-derived protein-ligand thermodynamics.

    Science.gov (United States)

    Grüner, Stefan; Neeb, Manuel; Barandun, Luzi Jakob; Sielaff, Frank; Hohn, Christoph; Kojima, Shun; Steinmetzer, Torsten; Diederich, François; Klebe, Gerhard

    2014-09-01

    The thermodynamic characterization of protein-ligand interactions by isothermal titration calorimetry (ITC) is a powerful tool in drug design, giving valuable insight into the interaction driving forces. ITC is thought to require protein and ligand solutions of high quality, meaning both the absence of contaminants as well as accurately determined concentrations. Ligands synthesized to deviating purity and protein of different pureness were titrated by ITC. Data curation was attempted also considering information from analytical techniques to correct stoichiometry. We used trypsin and tRNA-guanine transglycosylase (TGT), together with high affinity ligands to investigate the effect of errors in protein concentration as well as the impact of ligand impurities on the apparent thermodynamics. We found that errors in protein concentration did not change the thermodynamic properties obtained significantly. However, most ligand impurities led to pronounced changes in binding enthalpy. If protein binding of the respective impurity is not expected, the actual ligand concentration was corrected for and the thus revised data compared to thermodynamic properties obtained with the respective pure ligand. Even in these cases, we observed differences in binding enthalpy of about 4kJ⋅mol(-1), which is considered significant. Our results indicate that ligand purity is the critical parameter to monitor if accurate thermodynamic data of a protein-ligand complex are to be recorded. Furthermore, artificially changing fitting parameters to obtain a sound interaction stoichiometry in the presence of uncharacterized ligand impurities may lead to thermodynamic parameters significantly deviating from the accurate thermodynamic signature. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Is adaptation. Truly an adaptation?

    Directory of Open Access Journals (Sweden)

    Thais Flores Nogueira Diniz

    2006-04-01

    Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning.

  19. Characterization and mucosal responses of interleukin 17 family ligand and receptor genes in channel catfish Ictalurus punctatus

    Science.gov (United States)

    Interleukin (IL) 17 family cytokines are important mediators of mucosal immune responses, tightly regulated by signals from the complex milieu of pathogenic and commensal microbes, epithelial cells and innate and adaptive leukocytes found at tissue barriers. In mammals, IL17 ligand expression has be...

  20. MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage

    DEFF Research Database (Denmark)

    Gold, Marielle C.; McLaren, James E.; Reistetter, Joseph A.

    2015-01-01

    with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped...

  1. MR1-restricted MAIT cells display ligand discrimination and pathogen selectivity through distinct T cell receptor usage

    DEFF Research Database (Denmark)

    Gold, Marielle C.; McLaren, James E.; Reistetter, Joseph A.

    2014-01-01

    with this interpretation, MAIT cell clones with distinct TCRs responded differentially to a riboflavin metabolite. These results suggest that MAIT cells can discriminate between pathogen-derived ligands in a clonotype-dependent manner, providing a basis for adaptive memory via recruitment of specific repertoires shaped...

  2. Adaptation is...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC

    vital sector is under threat. While it is far from the only development challenge facing local farmers, extreme variations in the climate of West Africa in the past several decades have dealt the region a bad hand. Drought and flood now follow each other in succession. Adaptation is... “The floods spoiled our harvests and we.

  3. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    and reciprocal adaptation of informal governance structure create ambiguity in situations of contingencies, which, subsequently, increases the likelihood of premature relationship termination. Using a large sample of exchange relationships in the global service provider industry, we find support for a hypothesis...

  4. Adaptation Insights

    International Development Research Centre (IDRC) Digital Library (Canada)

    be given greater access to relevant information to help them adapt their farming practices and socio- economic strategies to climate change? To address this challenge, the project “InfoClim,” led by Senegal's. Ecological Monitoring Centre. (CSE) with support from the. CCAA program, aims at improving the access of farmers ...

  5. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Kongshaug, Jesper; Søndergaard, Karin

    2015-01-01

    differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial lighting ceases...

  6. Fluorescent BINOL-based sensor for thorium recognition and a density functional theory investigation

    International Nuclear Information System (INIS)

    Wen, Jun; Dong, Liang; Tian, Jie; Jiang, Tao; Yang, Yan-Qiu; Huang, Zeng; Yu, Xiao-Qi; Hu, Chang-Wei; Hu, Sheng; Yang, Tong-Zai; Wang, Xiao-Lin

    2013-01-01

    Graphical abstract: A novel BINOL fluorescence sensor L-1 for the recognition of thorium ion with high selectivity and sensitivity. -- Highlights: • The first case of one-to-one stoichiometric responding fluorescent sensor for thorium. • An easy preparation and novel BINOL-based chemical sensor. • This sensor for thorium ion recognition by fluorescence spectrophotometry with high selectivity and sensitivity. • This sensor shows good accuracy for analysis of thorium ions in river water. • DFT calculations indicate that a strong binding interaction exists between the L-1 and Th 4+ . -- Abstract: A novel 1,1′-bi-2-naphthol (BINOL) derivative fluorescence sensor L-1 for the recognition of thorium ion with a fluorescence quench response. This ligand showed high selectivity and sensitivity for thorium ion recognition. Coordination effects were investigated by DFT calculations, and the coordination modes and sites were confirmed. Moreover, the coordination abilities of the L-1 ligand with Th 4+ and UO 2 2+ were evaluated

  7. Immobilisation of ligands by radio-derivatized polymers; Immobilisering av ligander med radioderiverte polymerer

    Energy Technology Data Exchange (ETDEWEB)

    Varga, J.M.; Fritsch, P.

    1995-01-30

    The invention relates to radio-derivatized polymers and a method of producing them by contacting non-polymerizable conjugands with radiolysable polymers in the presence of irradiation. The resulting radio-derivatized polymers can be further linked with ligand of organic or inorganic nature to immobilize such ligands. 2 figs., 5 tabs.

  8. A General Ligand Design for Gold Catalysis allowing Ligand-Directed Anti Nucleophilic Attack of Alkynes

    Science.gov (United States)

    Wang, Yanzhao; Wang, Zhixun; Li, Yuxue; Wu, Gongde; Cao, Zheng; Zhang, Liming

    2014-01-01

    Most homogenous gold catalyses demand ≥0.5 mol % catalyst loading. Due to the high cost of gold, these reactions are unlikely to be applicable in medium or large scale applications. Here we disclose a novel ligand design based on the privileged biphenyl-2-phosphine framework that offers a potentially general approach to dramatically lowering catalyst loading. In this design, an amide group at the 3’ position of the ligand framework directs and promotes nucleophilic attack at the ligand gold complex-activated alkyne, which is unprecedented in homogeneous gold catalysis considering the spatial challenge of using ligand to reach antiapproaching nucleophile in a linear P-Au-alkyne centroid structure. With such a ligand, the gold(I) complex becomes highly efficient in catalyzing acid addition to alkynes, with a turnover number up to 99,000. Density functional theory calculations support the role of the amide moiety in directing the attack of carboxylic acid via hydrogen bonding. PMID:24704803

  9. A new class of PN3-pincer ligands for metal–ligand cooperative catalysis

    KAUST Repository

    Li, Huaifeng

    2014-12-01

    Work on a new class of PN3-pincer ligands for metal-ligand cooperative catalysis is reviewed. While the field of the pyridine-based PN3-transition metal pincer complexes is still relatively young, many important applications of these complexes have already emerged. In several cases, the PN3-pincer complexes for metal-ligand cooperative catalysis result in significantly improved or unprecedented activities. The synthesis and coordination chemistry of PN3-pincer ligands are briefly summarized first to cover the synthetic routes for their preparation, followed by a focus review on their applications in catalysis. A specific emphasis is placed on the later section about the role of PN3-pincer ligands\\' dearomatization-rearomatization steps during the catalytic cycles. The mechanistic insights from density functional theory (DFT) calculations are also discussed.

  10. Innate recognition of microbial-derived signals in immunity and inflammation.

    Science.gov (United States)

    Zhang, Yue; Liang, Chunli

    2016-12-01

    Microbes generate a vast array of different types of conserved structural components called pathogen-associated molecular patterns (PAMPs), which can be recognized by cells of the innate immune system. This recognition of "nonself" signatures occurs through host pattern recognition receptors (PRRs), suggesting that microbial-derived signals are good targets for innate immunity to discriminate between self- and nonself. Such PAMP-PRR interactions trigger multiple but distinct downstream signaling cascades, subsequently leading to production of proinflammatory cytokines and interferons that tailor immune responses to particular microbes. Aberrant PRR signals have been associated with various inflammatory diseases and fine regulation of PRR signaling is essential for avoiding excessive inflammatory immune responses and maintaining immune homeostasis. In this review we summarize the ligands and signal transduction pathways of PRRs and highlight recent progress of the mechanisms involved in microbe-specific innate immune recognition during immune responses and inflammation, which may provide new targets for therapeutic intervention to the inflammatory disorders.

  11. Recognition of Aircraft Engine Sound Based on GMM-UBM Model

    Directory of Open Access Journals (Sweden)

    Yuan Shuai

    2017-01-01

    Full Text Available Gaussian mixture model-universal background model (GMM-UBM is a commonly-used speaker recognition technology, and which has achieved good effect for detection speaker’s sound. In this paper, we explore GMM-UBM method for use with abnormal aircraft engine sound detection. We designed a GMM-UBM based aircraft engine sound recognition system, which extracts MFCC feature parameters and trains the GMM-UBM models using maximum a posteriori (MAP adaptive algorithm. Experimental results show the GMM-UBM based aircraft engine sound recognition system can achieve higher recognize rate in real-word aircraft engine sound test.

  12. Neuro System Structure for Vehicle Recognition and Count in Floating Bridge Specific Conditions

    Directory of Open Access Journals (Sweden)

    Slobodan Beroš

    2012-10-01

    Full Text Available The paper presents the research of the sophisticated vehiclerecognition and count system based on the application of theneural network. The basic elements of neural network andadaptive logic network for object recognition are discussed. Theadaptive logic network solution ability based on simple digitalcircuits as crucial in real-time applications is pointed out. Thesimulation based on the use of reduced high level noise pictureand a tree 2. 7. software have shown excellent results. The consideredand simulated adaptive neural network based systemwith its good recognition and convergence is a useful real-timesolution for vehicle recognition and count in the floating bridgesevere conditions.

  13. Effects of PPARγ ligands on vascular tone.

    Science.gov (United States)

    Salomone, Salvatore; Drago, Filippo

    2012-06-01

    Peroxisome Proliferator-Activated Receptor γ (PPARγ), originally described as a transcription factor for genes of carbohydrate and lipid metabolism, has been more recently studied in the context of cardiovascular pathophysiology. Here, we review the available data on PPARγ ligands as modulator of vascular tone. PPARγ ligands include: thiazolidinediones (used in the treatment of type 2 diabetes mellitus), glitazars (bind and activate both PPARγ and PPARα), and other experimental drugs (still in development) that exploit the chemistry of thiazolidinediones as a scaffold for PPARγ-independent pharmacological properties. In this review, we examine both short (mostly from in vitro data)- and long (mostly from in vivo data)-term effects of PPARγ ligands that extend from PPARγ-independent vascular effects to PPARγ-dependent gene expression. Because endothelium is a master regulator of vascular tone, we have attempted to differentiate between endothelium-dependent and endothelium-independent effects of PPARγ ligands. Based on available data, we conclude that PPARγ ligands appear to influence vascular tone in different experimental paradigms, most often in terms of vasodilatation (potentially increasing blood flow to some tissues). These effects on vascular tone, although potentially beneficial, must be weighed against specific cardiovascular warnings that may apply to some drugs, such as rosiglitazone.

  14. Dockomatic - automated ligand creation and docking.

    Science.gov (United States)

    Bullock, Casey W; Jacob, Reed B; McDougal, Owen M; Hampikian, Greg; Andersen, Tim

    2010-11-08

    The application of computational modeling to rationally design drugs and characterize macro biomolecular receptors has proven increasingly useful due to the accessibility of computing clusters and clouds. AutoDock is a well-known and powerful software program used to model ligand to receptor binding interactions. In its current version, AutoDock requires significant amounts of user time to setup and run jobs, and collect results. This paper presents DockoMatic, a user friendly Graphical User Interface (GUI) application that eases and automates the creation and management of AutoDock jobs for high throughput screening of ligand to receptor interactions. DockoMatic allows the user to invoke and manage AutoDock jobs on a single computer or cluster, including jobs for evaluating secondary ligand interactions. It also automates the process of collecting, summarizing, and viewing results. In addition, DockoMatic automates creation of peptide ligand .pdb files from strings of single-letter amino acid abbreviations. DockoMatic significantly reduces the complexity of managing multiple AutoDock jobs by facilitating ligand and AutoDock job creation and management.

  15. Dockomatic - automated ligand creation and docking

    Directory of Open Access Journals (Sweden)

    Hampikian Greg

    2010-11-01

    Full Text Available Abstract Background The application of computational modeling to rationally design drugs and characterize macro biomolecular receptors has proven increasingly useful due to the accessibility of computing clusters and clouds. AutoDock is a well-known and powerful software program used to model ligand to receptor binding interactions. In its current version, AutoDock requires significant amounts of user time to setup and run jobs, and collect results. This paper presents DockoMatic, a user friendly Graphical User Interface (GUI application that eases and automates the creation and management of AutoDock jobs for high throughput screening of ligand to receptor interactions. Results DockoMatic allows the user to invoke and manage AutoDock jobs on a single computer or cluster, including jobs for evaluating secondary ligand interactions. It also automates the process of collecting, summarizing, and viewing results. In addition, DockoMatic automates creation of peptide ligand .pdb files from strings of single-letter amino acid abbreviations. Conclusions DockoMatic significantly reduces the complexity of managing multiple AutoDock jobs by facilitating ligand and AutoDock job creation and management.

  16. Chelating ligands for nanocrystals' surface functionalization.

    Science.gov (United States)

    Querner, Claudia; Reiss, Peter; Bleuse, Joël; Pron, Adam

    2004-09-22

    A new family of ligands for the surface functionalization of CdSe nanocrystals is proposed, namely alkyl or aryl derivatives of carbodithioic acids (R-C(S)SH). The main advantages of these new ligands are as follows: they nearly quantitatively exchange the initial surface ligands (TOPO) in very mild conditions; they significantly improve the resistance of nanocrystals against photooxidation because of their ability of strong chelate-type binding to metal atoms; their relatively simple preparation via Grignard intermediates facilitates the development of new bifunctional ligands containing, in addition to the anchoring carbodithioate group, a second function, which enables the grafting of molecules or macromolecules of interest on the nanocrystal surface. To give an example of this approach, we report, for the first time, the grafting of an electroactive oligomer from the polyaniline family-aniline tetramer-on CdSe nanocrystals after their functionalization with 4-formyldithiobenzoic acid. The grafting proceeds via a condensation reaction between the aldehyde group of the ligand and the terminal primary amine group of the tetramer. The resulting organic/inorganic hybrid exhibits complete extinction of the fluorescence of its constituents, indicating efficient charge or energy transfer between the organic and the inorganic semiconductors.

  17. Fast Radioactive Nuclide Recognition Method Study Based on Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Yonggang Huo

    2014-01-01

    Full Text Available Based on pattern recognition method, applied the nuclear radiation digital measurement and analysis system platform, through synthetically making use of the radioactive nuclide’s ray information, selected radiation characteristic information of the radioactive nuclide, established the characteristic arrays database of radioactive nuclides, the recognition method is designed and applied to the identification of radionuclide radiation while using middle or low-resolution detector in this paper. Verified by experiments, when the count value of the traditional low-resolution spectrometer system is not reach single full energy peak’s statistical lower limit value, the three kinds of mixed radioactive nuclides’ true discrimination rate reached more than 90 % in the digital measurement and analysis system using fast radionuclide recognition method. The results show that this method is obviously superior to the traditional methods, and effectively improve the rapid identification ability to radioactive nuclide.

  18. Atomic interactions of neonicotinoid agonists with AChBP: Molecular recognition of the distinctive electronegative pharmacophore

    Energy Technology Data Exchange (ETDEWEB)

    Talley, Todd T.; Harel, Michal; Hibbs, Ryan E.; Radi, Zoran; Tomizawa, Motohiro; Casida, John E.; Taylor, Palmer (UCB); (UCSD)

    2008-07-28

    Acetylcholine-binding proteins (AChBPs) from mollusks are suitable structural and functional surrogates of the nicotinic acetylcholine receptors when combined with transmembrane spans of the nicotinic receptor. These proteins assemble as a pentamer with identical ACh binding sites at the subunit interfaces and show ligand specificities resembling those of the nicotinic receptor for agonists and antagonists. A subset of ligands, termed the neonicotinoids, exhibit specificity for insect nicotinic receptors and selective toxicity as insecticides. AChBPs are of neither mammalian nor insect origin and exhibit a distinctive pattern of selectivity for the neonicotinoid ligands. We define here the binding orientation and determinants of differential molecular recognition for the neonicotinoids and classical nicotinoids by estimates of kinetic and equilibrium binding parameters and crystallographic analysis. Neonicotinoid complex formation is rapid and accompanied by quenching of the AChBP tryptophan fluorescence. Comparisons of the neonicotinoids imidacloprid and thiacloprid in the binding site from Aplysia californica AChBP at 2.48 and 1.94 {angstrom} in resolution reveal a single conformation of the bound ligands with four of the five sites occupied in the pentameric crystal structure. The neonicotinoid electronegative pharmacophore is nestled in an inverted direction compared with the nicotinoid cationic functionality at the subunit interfacial binding pocket. Characteristic of several agonists, loop C largely envelops the ligand, positioning aromatic side chains to interact optimally with conjugated and hydrophobic regions of the neonicotinoid. This template defines the association of interacting amino acids and their energetic contributions to the distinctive interactions of neonicotinoids.

  19. Ligand identification using electron-density map correlations

    International Nuclear Information System (INIS)

    Terwilliger, Thomas C.; Adams, Paul D.; Moriarty, Nigel W.; Cohn, Judith D.

    2007-01-01

    An automated ligand-fitting procedure is applied to (F o − F c )exp(iϕ c ) difference density for 200 commonly found ligands from macromolecular structures in the Protein Data Bank to identify ligands from density maps. A procedure for the identification of ligands bound in crystal structures of macromolecules is described. Two characteristics of the density corresponding to a ligand are used in the identification procedure. One is the correlation of the ligand density with each of a set of test ligands after optimization of the fit of that ligand to the density. The other is the correlation of a fingerprint of the density with the fingerprint of model density for each possible ligand. The fingerprints consist of an ordered list of correlations of each the test ligands with the density. The two characteristics are scored using a Z-score approach in which the correlations are normalized to the mean and standard deviation of correlations found for a variety of mismatched ligand-density pairs, so that the Z scores are related to the probability of observing a particular value of the correlation by chance. The procedure was tested with a set of 200 of the most commonly found ligands in the Protein Data Bank, collectively representing 57% of all ligands in the Protein Data Bank. Using a combination of these two characteristics of ligand density, ranked lists of ligand identifications were made for representative (F o − F c )exp(iϕ c ) difference density from entries in the Protein Data Bank. In 48% of the 200 cases, the correct ligand was at the top of the ranked list of ligands. This approach may be useful in identification of unknown ligands in new macromolecular structures as well as in the identification of which ligands in a mixture have bound to a macromolecule

  20. Adaptation Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Huq, Saleemul

    2011-11-15

    Efforts to help the world's poor will face crises in coming decades as climate change radically alters conditions. Action Research for Community Adapation in Bangladesh (ARCAB) is an action-research programme on responding to climate change impacts through community-based adaptation. Set in Bangladesh at 20 sites that are vulnerable to floods, droughts, cyclones and sea level rise, ARCAB will follow impacts and adaptation as they evolve over half a century or more. National and international 'research partners', collaborating with ten NGO 'action partners' with global reach, seek knowledge and solutions applicable worldwide. After a year setting up ARCAB, we share lessons on the programme's design and move into our first research cycle.

  1. Adaptive sampler

    Science.gov (United States)

    Watson, B.L.; Aeby, I.

    1980-08-26

    An adaptive data compression device for compressing data is described. The device has a frequency content, including a plurality of digital filters for analyzing the content of the data over a plurality of frequency regions, a memory, and a control logic circuit for generating a variable rate memory clock corresponding to the analyzed frequency content of the data in the frequency region and for clocking the data into the memory in response to the variable rate memory clock.

  2. Adaptive positioner

    International Nuclear Information System (INIS)

    Labrador Pavon, I.

    1993-01-01

    This paper describes the circuits and programs in assembly language, developed to control the two DC motors that give mobility to a mechanical arm with two degrees of freedom. As a whole, the system is based in a adaptable regulator designed around a 8 bit microprocessor that, starting from a mode of regulation based in the successive approximation method, evolve to another mode through which, only one approximation is sufficient to get the right position of each motor. (Author) 6 refs

  3. Adaptable positioner

    International Nuclear Information System (INIS)

    Labrador Pavon, I.

    1993-01-01

    This paper describes the circuits and programs in assembly language, developed to control the two DC motors that give mobility to a mechanical arm with two degrees of freedom. As a whole, the system is based in a adaptable regulator designed around a 8 bit microprocessor that, starting from a mode of regulation based in the successive approximation method, evolve to another mode through which, only one approximation is sufficient to get the right position of each motor. (Author) 22 fig. 6 ref

  4. ADAPTATION EVALUATION

    Directory of Open Access Journals (Sweden)

    Björn PETERS, M.Sc.

    2001-01-01

    Full Text Available Twenty subjects with lower limb disabilities participated in a simulator study. The purpose of the study was to investigate how an Adaptive Cruise Control (ACC system together with two different hand controls for accelerator and brake influenced workload, comfort and driving behaviour and to further develop a method to evaluate vehicle adaptations for drivers with disabilities. The installed ACC system could maintain a constant speed selected and set by the driver and it also adapted speed in order to keep a safe distance to a leading vehicle. Furthermore, it included a stop-and-go function. Two common types of hand controls for accelerator and brake were used. The hand controls were different both with respect to function, single or dual levers, and position, on the steering column or between the front seats. The subjects were all experienced drivers of adapted cars equipped with hand controls. All subjects drove 100km at two occasions, with and without the ACC system available but with the same hand control. Subjective workload was found to be significantly lower and performance better for the ACC condition. The difference in speed variation between manual and ACC supported driving increased with the distance driven which seems to support the previous finding. The subjects thought they could control both speed and distance to leading vehicles better while the ACC was available. ACC driving did not influence reaction time, speed level, lateral position or variation in lateral position. Headway during car following situations was shorter for the ACC condition compared to manual driving. The ACC was well received, trusted and wanted. It was concluded that the ACC system substantially decreased workload, increased comfort and did not influence safety negatively. The only difference found between the two types of hand controls was that drivers using the dual lever system had less variation in lateral position. The applied evaluation method proved

  5. Effects of PPARγ Ligands on Leukemia

    Directory of Open Access Journals (Sweden)

    Yoko Tabe

    2012-01-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs and retinoic acid receptors (RARs, members of the nuclear receptor superfamily, are transcription factors that regulate a variety of important cellular functions. PPARs form heterodimers retinoid X receptor (RXR, an obligate heterodimeric partner for other nuclear receptors. Several novel links between retinoid metabolism and PPAR responses have been identified, and activation of PPAR/RXR expression has been shown to increase response to retinoids. PPARγ has emerged as a key regulator of cell growth and survival, whose activity is modulated by a number of synthetic and natural ligands. While clinical trials in cancer patients with thiazolidinediones (TZD have been disappointing, novel structurally different PPARγ ligands, including triterpenoids, have entered clinical arena as therapeutic agents for epithelial and hematopoietic malignancies. Here we shall review the antitumor advances of PPARγ, alone and in combination with RARα ligands in control of cell proliferation, differentiation, and apoptosis and their potential therapeutic applications in hematological malignancies.

  6. Individual Recognition in Ant Queens

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia; Heinze, Jürgen

    2005-01-01

    Personal relationships are the cornerstone of vertebrate societies, but insect societies are either too large for individual recognition, or their members were assumed to lack the necessary cognitive abilities 1 and 2 . This paradigm has been challenged by the recent discovery that paper wasps...... recognize each other's unique facial color patterns [3] . Individual recognition is advantageous when dominance hierarchies control the partitioning of work and reproduction 2 and 4 . Here, we show that unrelated founding queens of the ant Pachycondyla villosa use chemical cues to recognize each other...... perception, was prevented and in tests with anaesthetized queens. The cuticular chemical profiles of queens were neither associated with dominance nor fertility and, therefore, do not represent status badges 5 and 6 , and nestmate queens did not share a common odor. Personal recognition facilitates...

  7. Face Recognition using Approximate Arithmetic

    DEFF Research Database (Denmark)

    Marso, Karol

    Face recognition is image processing technique which aims to identify human faces and found its use in various different fields for example in security. Throughout the years this field evolved and there are many approaches and many different algorithms which aim to make the face recognition as effective...... as possible. The use of different approaches such as neural networks and machine learning can lead to fast and efficient solutions however, these solutions are expensive in terms of hardware resources and power consumption. A possible solution to this problem can be use of approximate arithmetic. In many image...... processing applications the results do not need to be completely precise and use of the approximate arithmetic can lead to reduction in terms of delay, space and power consumption. In this paper we examine possible use of approximate arithmetic in face recognition using Eigenfaces algorithm....

  8. Mandarin recognition over the telephone

    Science.gov (United States)

    Kao, Yuhung

    1996-06-01

    Mandarin Chinese is the official language in China and Taiwan, it is the native language of a quarter of the world population. As the services enabled by speech recognition technology (e.g. telephone voice dialing, information query) become more popular in English, we would like to extend this capability to other languages. Mandarin is one of the major languages under research in our laboratory. This paper describes how we extend our work in English speech recognition into Mandarin. We will described the corpus: Voice Across Taiwan, the training of a complete set of Mandarin syllable models, preliminary performance results and error analysis. A fast prototyping system was built, where a user can write any context free grammar with no restriction of vocabulary, then the grammar can be compiled into recognition models. It enables user to quickly test the performance of a new vocabulary.

  9. Doubling the Size of the Glucocorticoid Receptor Ligand Binding Pocket by Deacylcortivazol

    Energy Technology Data Exchange (ETDEWEB)

    Suino-Powell, Kelly; Xu, Yong; Zhang, Chenghai; Tao, Yong-guang; Tolbert, W. David; Simons, Jr., S. Stoney; Xu, H. Eric (NIH)

    2010-03-08

    A common feature of nuclear receptor ligand binding domains (LBD) is a helical sandwich fold that nests a ligand binding pocket within the bottom half of the domain. Here we report that the ligand pocket of glucocorticoid receptor (GR) can be continuously extended into the top half of the LBD by binding to deacylcortivazol (DAC), an extremely potent glucocorticoid. It has been puzzling for decades why DAC, which contains a phenylpyrazole replacement at the conserved 3-ketone of steroid hormones that are normally required for activation of their cognate receptors, is a potent GR activator. The crystal structure of the GR LBD bound to DAC and the fourth LXXLL motif of steroid receptor coactivator 1 reveals that the GR ligand binding pocket is expanded to a size of 1,070 {angstrom}{sup 3}, effectively doubling the size of the GR dexamethasone-binding pocket of 540 {angstrom}{sup 3} and yet leaving the structure of the coactivator binding site intact. DAC occupies only {approx}50% of the space of the pocket but makes intricate interactions with the receptor around the phenylpyrazole group that accounts for the high-affinity binding of DAC. The dramatic expansion of the DAC-binding pocket thus highlights the conformational adaptability of GR to ligand binding. The new structure also allows docking of various nonsteroidal ligands that cannot be fitted into the previous structures, thus providing a new rational template for drug discovery of steroidal and nonsteroidal glucocorticoids that can be specifically designed to reach the unoccupied space of the expanded pocket.

  10. Simultaneous tracking and activity recognition

    DEFF Research Database (Denmark)

    Manfredotti, Cristina Elena; Fleet, David J.; Hamilton, Howard J.

    2011-01-01

    Many tracking problems involve several distinct objects interacting with each other. We develop a framework that takes into account interactions between objects allowing the recognition of complex activities. In contrast to classic approaches that consider distinct phases of tracking and activity...... recognition, our framework performs these two tasks simultaneously. In particular, we adopt a Bayesian standpoint where the system maintains a joint distribution of the positions, the interactions and the possible activities. This turns out to be advantegeous, as information about the ongoing activities can...

  11. Discriminative learning for speech recognition

    CERN Document Server

    He, Xiadong

    2008-01-01

    In this book, we introduce the background and mainstream methods of probabilistic modeling and discriminative parameter optimization for speech recognition. The specific models treated in depth include the widely used exponential-family distributions and the hidden Markov model. A detailed study is presented on unifying the common objective functions for discriminative learning in speech recognition, namely maximum mutual information (MMI), minimum classification error, and minimum phone/word error. The unification is presented, with rigorous mathematical analysis, in a common rational-functio

  12. Iris Recognition for Human Identification

    Science.gov (United States)

    Alandkar, Lajari; Gengaje, Sachin

    2010-11-01

    Iris recognition system is the biometric identification system. Iris has an intricate structure, uniqueness, stability, and natural protection. Due to these features of the iris it can be used for biometric identification. This system gives better performance than other biometric identification systems. A novel eyelash removal method for preprocessing of human iris images in a human iris recognition system is presented.. Discrete cosine transform (DCT) method is used for feature extraction. For matching of two-iris code Hamming distance calculation is used. EER value must be less for the optimum performance of the system.

  13. Human ear recognition by computer

    CERN Document Server

    Bhanu, Bir; Chen, Hui

    2010-01-01

    Biometrics deals with recognition of individuals based on their physiological or behavioral characteristics. The human ear is a new feature in biometrics that has several merits over the more common face, fingerprint and iris biometrics. Unlike the fingerprint and iris, it can be easily captured from a distance without a fully cooperative subject, although sometimes it may be hidden with hair, scarf and jewellery. Also, unlike a face, the ear is a relatively stable structure that does not change much with the age and facial expressions. ""Human Ear Recognition by Computer"" is the first book o

  14. Unequal recognition, misrecognition and injustice

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2012-01-01

    Euro-multiculturalism is (1) concerned with religiously defined immigrant minorities; (2) sees policies of recognition as a means to secure multicultural equality between groups; (3) endorses the moderate secularism of European states; and (4) adopts a contextualist approach to answering the norm......Euro-multiculturalism is (1) concerned with religiously defined immigrant minorities; (2) sees policies of recognition as a means to secure multicultural equality between groups; (3) endorses the moderate secularism of European states; and (4) adopts a contextualist approach to answering...

  15. Familiar Person Recognition: Is Autonoetic Consciousness More Likely to Accompany Face Recognition Than Voice Recognition?

    Science.gov (United States)

    Barsics, Catherine; Brédart, Serge

    2010-11-01

    Autonoetic consciousness is a fundamental property of human memory, enabling us to experience mental time travel, to recollect past events with a feeling of self-involvement, and to project ourselves in the future. Autonoetic consciousness is a characteristic of episodic memory. By contrast, awareness of the past associated with a mere feeling of familiarity or knowing relies on noetic consciousness, depending on semantic memory integrity. Present research was aimed at evaluating whether conscious recollection of episodic memories is more likely to occur following the recognition of a familiar face than following the recognition of a familiar voice. Recall of semantic information (biographical information) was also assessed. Previous studies that investigated the recall of biographical information following person recognition used faces and voices of famous people as stimuli. In this study, the participants were presented with personally familiar people's voices and faces, thus avoiding the presence of identity cues in the spoken extracts and allowing a stricter control of frequency exposure with both types of stimuli (voices and faces). In the present study, the rate of retrieved episodic memories, associated with autonoetic awareness, was significantly higher from familiar faces than familiar voices even though the level of overall recognition was similar for both these stimuli domains. The same pattern was observed regarding semantic information retrieval. These results and their implications for current Interactive Activation and Competition person recognition models are discussed.

  16. Ligand Exchange and 1H NMR Quantification of Single- and Mixed-Moiety Thiolated Ligand Shells on Gold Nanoparticles.

    Science.gov (United States)

    Smith, Ashley M; Millstone, Jill E

    2017-01-01

    The use of nanoparticles in biomedicine critically depends on their surface chemistry. For metal nanoparticles, a common way to tune this surface chemistry is through mass action ligand exchange, where ligand exchange can be used to expand the functionality of the resulting nanoparticle conjugates. Specifically, the quantity, identity, and arrangement of the molecules in the resulting ligand shell each can be tuned significantly. Here, we describe methods to exchange and quantify thiolated and non-thiolated ligands on gold nanoparticle surfaces. Importantly, these strategies allow the quantification of multiple ligand types within a single ligand shell, simultaneously providing ligand composition and ligand density information. These results are crucial for both designing and assigning structure-function relationships in bio-functionalized nanoparticles, and these methods can be applied to a broad range of nanoparticle cores and ligand types including peptides, small molecule drugs, and oligonucleotides.

  17. Relative preservation of the recognition of positive facial expression "happiness" in Alzheimer disease.

    Science.gov (United States)

    Maki, Yohko; Yoshida, Hiroshi; Yamaguchi, Tomoharu; Yamaguchi, Haruyasu

    2013-01-01

    Positivity recognition bias has been reported for facial expression as well as memory and visual stimuli in aged individuals, whereas emotional facial recognition in Alzheimer disease (AD) patients is controversial, with possible involvement of confounding factors such as deficits in spatial processing of non-emotional facial features and in verbal processing to express emotions. Thus, we examined whether recognition of positive facial expressions was preserved in AD patients, by adapting a new method that eliminated the influences of these confounding factors. Sensitivity of six basic facial expressions (happiness, sadness, surprise, anger, disgust, and fear) was evaluated in 12 outpatients with mild AD, 17 aged normal controls (ANC), and 25 young normal controls (YNC). To eliminate the factors related to non-emotional facial features, averaged faces were prepared as stimuli. To eliminate the factors related to verbal processing, the participants were required to match the images of stimulus and answer, avoiding the use of verbal labels. In recognition of happiness, there was no difference in sensitivity between YNC and ANC, and between ANC and AD patients. AD patients were less sensitive than ANC in recognition of sadness, surprise, and anger. ANC were less sensitive than YNC in recognition of surprise, anger, and disgust. Within the AD patient group, sensitivity of happiness was significantly higher than those of the other five expressions. In AD patient, recognition of happiness was relatively preserved; recognition of happiness was most sensitive and was preserved against the influences of age and disease.

  18. Multispectral image fusion for illumination-invariant palmprint recognition

    Science.gov (United States)

    Zhang, Xinman; Xu, Xuebin; Shang, Dongpeng

    2017-01-01

    Multispectral palmprint recognition has shown broad prospects for personal identification due to its high accuracy and great stability. In this paper, we develop a novel illumination-invariant multispectral palmprint recognition method. To combine the information from multiple spectral bands, an image-level fusion framework is completed based on a fast and adaptive bidimensional empirical mode decomposition (FABEMD) and a weighted Fisher criterion. The FABEMD technique decomposes the multispectral images into their bidimensional intrinsic mode functions (BIMFs), on which an illumination compensation operation is performed. The weighted Fisher criterion is to construct the fusion coefficients at the decomposition level, making the images be separated correctly in the fusion space. The image fusion framework has shown strong robustness against illumination variation. In addition, a tensor-based extreme learning machine (TELM) mechanism is presented for feature extraction and classification of two-dimensional (2D) images. In general, this method has fast learning speed and satisfying recognition accuracy. Comprehensive experiments conducted on the PolyU multispectral palmprint database illustrate that the proposed method can achieve favorable results. For the testing under ideal illumination, the recognition accuracy is as high as 99.93%, and the result is 99.50% when the lighting condition is unsatisfied. PMID:28558064

  19. Sensor agnostic object recognition using a map seeking circuit

    Science.gov (United States)

    Overman, Timothy L.; Hart, Michael

    2012-05-01

    Automatic object recognition capabilities are traditionally tuned to exploit the specific sensing modality they were designed to. Their successes (and shortcomings) are tied to object segmentation from the background, they typically require highly skilled personnel to train them, and they become cumbersome with the introduction of new objects. In this paper we describe a sensor independent algorithm based on the biologically inspired technology of map seeking circuits (MSC) which overcomes many of these obstacles. In particular, the MSC concept offers transparency in object recognition from a common interface to all sensor types, analogous to a USB device. It also provides a common core framework that is independent of the sensor and expandable to support high dimensionality decision spaces. Ease in training is assured by using commercially available 3D models from the video game community. The search time remains linear no matter how many objects are introduced, ensuring rapid object recognition. Here, we report results of an MSC algorithm applied to object recognition and pose estimation from high range resolution radar (1D), electrooptical imagery (2D), and LIDAR point clouds (3D) separately. By abstracting the sensor phenomenology from the underlying a prior knowledge base, MSC shows promise as an easily adaptable tool for incorporating additional sensor inputs.

  20. Cognitive penetrability and emotion recognition in human facial expressions

    Directory of Open Access Journals (Sweden)

    Francesco eMarchi

    2015-06-01

    Full Text Available Do our background beliefs, desires, and mental images influence our perceptual experience of the emotions of others? In this paper, we will address the possibility of cognitive penetration of perceptual experience in the domain of social cognition. In particular, we focus on emotion recognition based on the visual experience of facial expressions. After introducing the current debate on cognitive penetration, we review examples of perceptual adaptation for facial expressions of emotion. This evidence supports the idea that facial expressions are perceptually processed as wholes. That is, the perceptual system integrates lower-level facial features, such as eyebrow orientation, mouth angle etc., into facial compounds. We then present additional experimental evidence showing that in some cases, emotion recognition on the basis of facial expression is sensitive to and modified by the background knowledge of the subject. We argue that such sensitivity is best explained as a difference in the visual experience of the facial expression, not just as a modification of the judgment based on this experience. The difference in experience is characterized as the result of the interference of background knowledge with the perceptual integration process for faces. Thus, according to the best explanation, we have to accept cognitive penetration in some cases of emotion recognition. Finally, we highlight a recent model of social vision in order to propose a mechanism for cognitive penetration used in the face-based recognition of emotion.

  1. Robust Tomato Recognition for Robotic Harvesting Using Feature Images Fusion

    Science.gov (United States)

    Zhao, Yuanshen; Gong, Liang; Huang, Yixiang; Liu, Chengliang

    2016-01-01

    Automatic recognition of mature fruits in a complex agricultural environment is still a challenge for an autonomous harvesting robot due to various disturbances existing in the background of the image. The bottleneck to robust fruit recognition is reducing influence from two main disturbances: illumination and overlapping. In order to recognize the tomato in the tree canopy using a low-cost camera, a robust tomato recognition algorithm based on multiple feature images and image fusion was studied in this paper. Firstly, two novel feature images, the  a*-component image and the I-component image, were extracted from the L*a*b* color space and luminance, in-phase, quadrature-phase (YIQ) color space, respectively. Secondly, wavelet transformation was adopted to fuse the two feature images at the pixel level, which combined the feature information of the two source images. Thirdly, in order to segment the target tomato from the background, an adaptive threshold algorithm was used to get the optimal threshold. The final segmentation result was processed by morphology operation to reduce a small amount of noise. In the detection tests, 93% target tomatoes were recognized out of 200 overall samples. It indicates that the proposed tomato recognition method is available for robotic tomato harvesting in the uncontrolled environment with low cost. PMID:26840313

  2. Cutting an NKG2D Ligand Short: Cellular Processing of the Peculiar Human NKG2D Ligand ULBP4

    Directory of Open Access Journals (Sweden)

    Tobias Zöller

    2018-03-01

    Full Text Available Stress-induced cell surface expression of MHC class I-related glycoproteins of the MIC and ULBP families allows for immune recognition of dangerous “self cells” by human cytotoxic lymphocytes via the NKG2D receptor. With two MIC molecules (MICA and MICB and six ULBP molecules (ULBP1–6, there are a total of eight human NKG2D ligands (NKG2DL. Since the discovery of the NKG2D–NKG2DL system, the cause for both redundancy and diversity of NKG2DL has been a major and ongoing matter of debate. NKG2DL diversity has been attributed, among others, to the selective pressure by viral immunoevasins, to diverse regulation of expression, to differential tissue expression as well as to variations in receptor interactions. Here, we critically review the current state of knowledge on the poorly studied human NKG2DL ULBP4. Summarizing available facts and previous studies, we picture ULBP4 as a peculiar ULBP family member distinct from other ULBP family members by various aspects. In addition, we provide novel experimental evidence suggesting that cellular processing gives rise to mature ULBP4 glycoproteins different to previous reports. Finally, we report on the proteolytic release of soluble ULBP4 and discuss these results in the light of known mechanisms for generation of soluble NKG2DL.

  3. Simple test system for single molecule recognition force microscopy

    International Nuclear Information System (INIS)

    Riener, Christian K.; Stroh, Cordula M.; Ebner, Andreas; Klampfl, Christian; Gall, Alex A.; Romanin, Christoph; Lyubchenko, Yuri L.; Hinterdorfer, Peter; Gruber, Hermann J.

    2003-01-01

    We have established an easy-to-use test system for detecting receptor-ligand interactions on the single molecule level using atomic force microscopy (AFM). For this, avidin-biotin, probably the best characterized receptor-ligand pair, was chosen. AFM sensors were prepared containing tethered biotin molecules at sufficiently low surface concentrations appropriate for single molecule studies. A biotin tether, consisting of a 6 nm poly(ethylene glycol) (PEG) chain and a functional succinimide group at the other end, was newly synthesized and covalently coupled to amine-functionalized AFM tips. In particular, PEG 800 diamine was glutarylated, the mono-adduct NH 2 -PEG-COOH was isolated by ion exchange chromatography and reacted with biotin succinimidylester to give biotin-PEG-COOH which was then activated as N-hydroxysuccinimide (NHS) ester to give the biotin-PEG-NHS conjugate which was coupled to the aminofunctionalized AFM tip. The motional freedom provided by PEG allows for free rotation of the biotin molecule on the AFM sensor and for specific binding to avidin which had been adsorbed to mica surfaces via electrostatic interactions. Specific avidin-biotin recognition events were discriminated from nonspecific tip-mica adhesion by their typical unbinding force (∼40 pN at 1.4 nN/s loading rate), unbinding length (<13 nm), the characteristic nonlinear force-distance relation of the PEG linker, and by specific block with excess of free d-biotin. The convenience of the test system allowed to evaluate, and compare, different methods and conditions of tip aminofunctionalization with respect to specific binding and nonspecific adhesion. It is concluded that this system is well suited as calibration or start-up kit for single molecule recognition force microscopy

  4. A2AR Binding Kinetics in the Ligand Depletion Regime.

    Science.gov (United States)

    McNeely, Patrick M; Naranjo, Andrea N; Forsten-Williams, Kimberly; Robinson, Anne Skaja

    2017-02-01

    Ligand binding plays a fundamental role in stimulating the downstream signaling of membrane receptors. Here, ligand-binding kinetics of the full-length human adenosine A 2A receptor (A 2A R) reconstituted in detergent micelles were measured using a fluorescently labeled ligand via fluorescence anisotropy. Importantly, to optimize the signal-to-noise ratio, these experiments were conducted in the ligand depletion regime. In the ligand depletion regime, the assumptions used to determine analytical solutions for one-site binding models for either one or two ligands in competition are no longer valid. We therefore implemented a numerical solution approach to analyze kinetic binding data as experimental conditions approach the ligand depletion regime. By comparing the results from the numerical and the analytical solutions, we highlight the ligand-receptor ratios at which the analytical solution begins to lose predictive accuracy. Using the numerical solution approach, we determined the kinetic rate constants of the fluorescent ligand, FITC-APEC, and those for three unlabeled ligands using competitive association experiments. The association and dissociation rate constants of the unlabeled ligands determined from the competitive association experiments were then independently validated using competitive dissociation data. Based on this study, a numerical solution is recommended to determine kinetic ligand-binding parameters for experiments conducted in the ligand-depletion regime.

  5. CHELATING LIGANDS: ENHANCERS OF QUALITY AND PURITY ...

    African Journals Online (AJOL)

    Nwokem et al.

    ABSTRACT. The quality of biogas depends largely on the percentage of methane and hydrogen sulphide gas present. High concentration of hydrogen sulphide results in low quality biogas. This work employed the use of chelating ligands in scrubbing hydrogen sulphide gas while improving the yield of methane gas.

  6. Ligand iron catalysts for selective hydrogenation

    Science.gov (United States)

    Casey, Charles P.; Guan, Hairong

    2010-11-16

    Disclosed are iron ligand catalysts for selective hydrogenation of aldehydes, ketones and imines. A catalyst such as dicarbonyl iron hydride hydroxycyclopentadiene) complex uses the OH on the five member ring and hydrogen linked to the iron to facilitate hydrogenation reactions, particularly in the presence of hydrogen gas.

  7. Versatile phosphite ligands based on silsesquioxane backbones

    NARCIS (Netherlands)

    van der Vlugt, JI; Ackerstaff, J; Dijkstra, TW; Mills, AM; Kooijman, H; Spek, AL; Meetsma, A; Abbenhuis, HCL; Vogt, D

    Silsesquioxanes are employed as ligand backbones for the synthesis of novel phosphite compounds with 3,3'-5,5'-tetrakis(tert-butyl)-2,2'-di-oxa-1,1'-biphenyl substituents. Both mono- and bidentate phosphites are prepared in good yields. Two types of silsesquioxanes are employed as starting

  8. Constitutive and ligand-induced TCR degradation

    DEFF Research Database (Denmark)

    von Essen, Marina; Bonefeld, Charlotte Menné; Siersma, Volkert

    2004-01-01

    divergent models for TCR down-regulation and degradation have been suggested. The aims of this study were to determine the rate constants for constitutive and ligand-induced TCR degradation and to determine whether the TCR subunits segregate or are processed as an intact unit during TCR down...

  9. Ligand based pharmacophore modelling of anticancer histone ...

    African Journals Online (AJOL)

    like myocardium damage and bone marrow depression even leading to cell death have been observed in the treatment of caner cells using HDAC inhibitors. The discovery and development of type-specific HDAC inhibitors is of both research and clinical interests. Ligand based pharmacophore modelling is playing a key ...

  10. Ligand Exchange Kinetics of Environmentally Relevant Metals

    Energy Technology Data Exchange (ETDEWEB)

    Panasci, Adele Frances [Univ. of California, Davis, CA (United States)

    2014-07-15

    The interactions of ground water with minerals and contaminants are of broad interest for geochemists but are not well understood. Experiments on the molecular scale can determine reaction parameters (i.e. rates of ligand exchange, activation entropy, activation entropy, and activation volume) that can be used in computations to gain insight into reactions that occur in natural groundwaters. Experiments to determine the rate of isotopic ligand exchange for three environmentally relevant metals, rhodium (Rh), iron (Fe), and neptunium (Np), are described. Many environmental transformations of metals (e.g. reduction) in soil occur at trivalent centers, Fe(III) in particular. Contaminant ions absorb to mineral surfaces via ligand exchange, and the reversal of this reaction can be dangerous, releasing contaminants into the environment. Ferric iron is difficult to study spectroscopically because most of its complexes are paramagnetic and are generally reactive toward ligand exchange; therefore, Rh(III), which is diamagnetic and less reactive, was used to study substitution reactions that are analogous to those that occur on mineral oxide surfaces. Studies on both Np(V) and Np(VI) are important in their own right, as 237Np is a radioactive transuranic element with a half-life of 2 million years.

  11. Dynamic Ligand Based Pharmacophore Modeling and Virtual ...

    Indian Academy of Sciences (India)

    user

    ChEMBL-HIV https://www.ebi.ac.uk/chembl/index.php/assay/results (ChEMBL Bioassay was searched with the key word “Human. Immunodefficiency virus”, display bioactivity option was chosen and then “Download All Bioactivity Data” was ... Ligand based pharmacophore models generated from the crystal structure and.

  12. Mixed-ligand binuclear copper(II)

    Indian Academy of Sciences (India)

    A new mixed-ligand binuclear copper(II) complex [Cu(MS)(bpy)]2.(ClO4)2, built of 5-methylsalicylaldehyde and 2,2'-bipyridyl has been synthesized and characterized by using elemental analysis, IR and UV-Vis spectroscopy. Crystal structure of the complex shows that copper(II) ion lies in a square pyramidal coordination ...

  13. A versatile dinucleating ligand containing sulfonamide groups

    DEFF Research Database (Denmark)

    Sundberg, Jonas; Witt, Hannes; Cameron, Lisa

    2014-01-01

    Copper, iron, and gallium coordination chemistries of the new pentadentate bis-sulfonamide ligand 2,6-bis(N-2-pyridylmethylsulfonamido)-4-methylphenol (psmpH3) were investigated. PsmpH3 is capable of varying degrees of deprotonation, and notably, complexes containing the fully trideprotonated...

  14. Amidinate Ligands in Zinc coordination sphere

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 6. Amidinate Ligands in Zinc coordination sphere: Synthesis and structural diversity. SRINIVAS ANGA INDRANI BANERJEE TARUN K PANDA. Regular Article Volume 128 Issue 6 June 2016 pp ... Keywords. Zinc; carbodiimides; amidinate; alkyl migration.

  15. Simple tertiary phosphines to hexaphosphane ligands: Syntheses ...

    Indian Academy of Sciences (India)

    In this context, we have developed new synthetic methodologies for making unusual inorganic ring systems containing trivalent phosphorus centres, novel phosphorus-based multidentate and hybrid ligands and explored their rich transition metal chemistry and catalytic applications. We have also fine tuned a few existing ...

  16. S3-2: Colorfulness Perception Adapting to Natural Scenes

    Directory of Open Access Journals (Sweden)

    Yoko Mizokami

    2012-10-01

    Full Text Available Our visual system has the ability to adapt to the color characteristics of environment and maintain stable color appearance. Many researches on chromatic adaptation and color constancy suggested that the different levels of visual processes involve the adaptation mechanism. In the case of colorfulness perception, it has been shown that the perception changes with adaptation to chromatic contrast modulation and to surrounding chromatic variance. However, it is still not clear how the perception changes in natural scenes and what levels of visual mechanisms contribute to the perception. Here, I will mainly present our recent work on colorfulness-adaptation in natural images. In the experiment, we examined whether the colorfulness perception of an image was influenced by the adaptation to natural images with different degrees of saturation. Natural and unnatural (shuffled or phase-scrambled images are used for adapting and test images, and all combinations of adapting and test images were tested (e.g., the combination of natural adapting images and a shuffled test image. The results show that colorfulness perception was influenced by adaptation to the saturation of images. A test image appeared less colorful after adaptation to saturated images, and vice versa. The effect of colorfulness adaptation was the strongest for the combination of natural adapting and natural test images. The fact that the naturalness of the spatial structure in an image affects the strength of the adaptation effect implies that the recognition of natural scene would play an important role in the adaptation mechanism.

  17. The Army word recognition system

    Science.gov (United States)

    Hadden, David R.; Haratz, David

    1977-01-01

    The application of speech recognition technology in the Army command and control area is presented. The problems associated with this program are described as well as as its relevance in terms of the man/machine interactions, voice inflexions, and the amount of training needed to interact with and utilize the automated system.

  18. Action Recognition using Motion Primitives

    DEFF Research Database (Denmark)

    Moeslund, Thomas B.; Fihl, Preben; Holte, Michael Boelstoft

    The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent...

  19. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Some of the history of gradual infusion of the modulation spectrum concept into Automatic recognition of speech (ASR) comes next, pointing to the relationship of modulation spectrum processing to wellaccepted ASR techniques such as dynamic speech features or RelAtive SpecTrAl (RASTA) filtering. Next ...

  20. Mobile Visual Recognition on Smartphones

    Directory of Open Access Journals (Sweden)

    Zhenwen Gui

    2013-01-01

    Full Text Available This paper addresses the recognition of large-scale outdoor scenes on smartphones by fusing outputs of inertial sensors and computer vision techniques. The main contributions can be summarized as follows. Firstly, we propose an ORD (overlap region divide method to plot image position area, which is fast enough to find the nearest visiting area and can also reduce the search range compared with the traditional approaches. Secondly, the vocabulary tree-based approach is improved by introducing GAGCC (gravity-aligned geometric consistency constraint. Our method involves no operation in the high-dimensional feature space and does not assume a global transform between a pair of images. Thus, it substantially reduces the computational complexity and memory usage, which makes the city scale image recognition feasible on the smartphone. Experiments on a collected database including 0.16 million images show that the proposed method demonstrates excellent recognition performance, while maintaining the average recognition time about 1 s.

  1. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    Abstract. Feature extraction is one of the important tasks in face recognition. Moments are widely used feature extractor due to their superior discriminatory power and geometrical invariance. Moments generally capture the global features of the image. This paper proposes Krawtchouk moment for feature extraction in face ...

  2. Target recognition by wavelet transform

    CERN Document Server

    Li Zheng Dong; He Wu Liang; Pei Chun Lan; Peng Wen; SongChen; Zheng Xiao Dong

    2002-01-01

    Wavelet transform has an important character of multi-resolution power, which presents pyramid structure, and this character coincides the way by which people distinguish object from coarse to fineness and from large to tiny. In addition to it, wavelet transform benefits to reducing image noise, simplifying calculation, and embodying target image characteristic point. A method of target recognition by wavelet transform is provided

  3. Face recognition, a landmarks tale

    NARCIS (Netherlands)

    Beumer, G.M.

    2009-01-01

    Face recognition is a technology that appeals to the imagination of many people. This is particularly reflected in the popularity of science-fiction films and forensic detective series such as CSI, CSI New York, CSI Miami, Bones and NCIS. Although these series tend to be set in the present, their

  4. Phosphate Recognition in Structural Biology

    NARCIS (Netherlands)

    Hirsch, Anna K.H.; Fischer, Felix R.; Diederich, François

    2007-01-01

    Drug-discovery research in the past decade has seen an increased selection of targets with phosphate recognition sites, such as protein kinases and phosphatases, in the past decade. This review attempts, with the help of database-mining tools, to give an overview of the most important principles in

  5. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Some of the history of gradual infusion of the modulation spectrum concept into Automatic recognition of speech (ASR) comes next, pointing to the relationship of modulation spectrum processing to wellaccepted ASR techniques such as dynamic speech features or RelAtive SpecTrAl (RASTA) filtering. Next, the frequency ...

  6. Selective Search for Object Recognition

    NARCIS (Netherlands)

    Uijlings, J.R.; van de Sande, K.E.A.; Gevers, T.; Smeulders, A.W.M.

    This paper addresses the problem of generating possible object locations for use in object recognition. We introduce selective search which combines the strength of both an exhaustive search and segmentation. Like segmentation, we use the image structure to guide our sampling process. Like

  7. Object Recognition by Contour Matching

    NARCIS (Netherlands)

    Ir Peter Boots; Ir. Dick van Schenk Brill

    2002-01-01

    This article deals with automatic object recognition. The goal is that in a certain grey-level image, possibly containing many objects, a certain object can be recognized and localized, based upon its shape. The assumption is that this shape has no special characteristics on which a dedicated

  8. Speech recognition implementation in radiology

    International Nuclear Information System (INIS)

    White, Keith S.

    2005-01-01

    Continuous speech recognition (SR) is an emerging technology that allows direct digital transcription of dictated radiology reports. The SR systems are being widely deployed in the radiology community. This is a review of technical and practical issues that should be considered when implementing an SR system. (orig.)

  9. Non-Intrusive Appliance Recognition

    NARCIS (Netherlands)

    Hoogsteen, G; Hoogsteen, Gerwin; Krist, J.O.; Bakker, Vincent; Smit, Gerardus Johannes Maria

    2012-01-01

    Energy conservation becomes more important nowadays. The use of smart meters and, in the near future, smart appliances, are the key to achieve reduction in energy consumption. This research proposes a non-intrusive appliance monitor and recognition system for implementation on an embedded system.

  10. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    automatic recognition of speech (ASR). Instead, likely for historical reasons, envelopes of power spectrum were adopted as main carrier of linguistic information in ASR. However, the relationships between phonetic values of sounds and their short-term spectral envelopes are not straightforward. Consequently, this asks for ...

  11. Matching score based face recognition

    NARCIS (Netherlands)

    Boom, B.J.; Beumer, G.M.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2006-01-01

    Accurate face registration is of vital importance to the performance of a face recognition algorithm. We propose a new method: matching score based face registration, which searches for optimal alignment by maximizing the matching score output of a classifier as a function of the different

  12. Motion Primitives for Action Recognition

    DEFF Research Database (Denmark)

    Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2007-01-01

    The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent t...

  13. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Feature extraction is one of the important tasks in face recognition. Moments are widely used feature extractor due to their superior discriminatory power and geometrical invariance. Moments generally capture the global features of the image. This paper proposes Krawtchouk moment for feature extraction ...

  14. Ear recognition: a complete system

    Science.gov (United States)

    Abaza, Ayman; Harrison, Mary Ann F.

    2013-05-01

    Ear Recognition has recently received significant attention in the literature. Even though current ear recognition systems have reached a certain level of maturity, their success is still limited. This paper presents an efficient complete ear-based biometric system that can process five frames/sec; Hence it can be used for surveillance applications. The ear detection is achieved using Haar features arranged in a cascaded Adaboost classifier. The feature extraction is based on dividing the ear image into several blocks from which Local Binary Pattern feature distributions are extracted. These feature distributions are then fused at the feature level to represent the original ear texture in the classification stage. The contribution of this paper is three fold: (i) Applying a new technique for ear feature extraction, and studying various optimization parameters for that technique; (ii) Presenting a practical ear recognition system and a detailed analysis about error propagation in that system; (iii) Studying the occlusion effect of several ear parts. Detailed experiments show that the proposed ear recognition system achieved better performance (94:34%) compared to other shape-based systems as Scale-invariant feature transform (67:92%). The proposed approach can also handle efficiently hair occlusion. Experimental results show that the proposed system can achieve about (78%) rank-1 identification, even in presence of 60% occlusion.

  15. Towards automatic forensic face recognition

    NARCIS (Netherlands)

    Ali, Tauseef; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2011-01-01

    In this paper we present a methodology and experimental results for evidence evaluation in the context of forensic face recognition. In forensic applications, the matching score (hereafter referred to as similarity score) from a biometric system must be represented as a Likelihood Ratio (LR). In our

  16. Discovery of Peptidomimetic Ligands of EED as Allosteric Inhibitors of PRC2

    Energy Technology Data Exchange (ETDEWEB)

    Barnash, Kimberly D.; The, Juliana; Norris-Drouin, Jacqueline L.; Cholensky, Stephanie H.; Worley, Beau M.; Li, Fengling; Stuckey, Jacob I.; Brown, Peter J.; Vedadi, Masoud; Arrowsmith, Cheryl H.; Frye, Stephen V.; James, Lindsey I. (UNC); (Toronto)

    2017-02-06

    The function of EED within polycomb repressive complex 2 (PRC2) is mediated by a complex network of protein–protein interactions. Allosteric activation of PRC2 by binding of methylated proteins to the embryonic ectoderm development (EED) aromatic cage is essential for full catalytic activity, but details of this regulation are not fully understood. EED’s recognition of the product of PRC2 activity, histone H3 lysine 27 trimethylation (H3K27me3), stimulates PRC2 methyltransferase activity at adjacent nucleosomes leading to H3K27me3 propagation and, ultimately, gene repression. By coupling combinatorial chemistry and structure-based design, we optimized a low-affinity methylated jumonji, AT-rich interactive domain 2 (Jarid2) peptide to a smaller, more potent peptidomimetic ligand (Kd = 1.14 ± 0.14 μM) of the aromatic cage of EED. Our strategy illustrates the effectiveness of applying combinatorial chemistry to achieve both ligand potency and property optimization. Furthermore, the resulting ligands, UNC5114 and UNC5115, demonstrate that targeted disruption of EED’s reader function can lead to allosteric inhibition of PRC2 catalytic activity.

  17. Improved Free-Energy Landscape Quantification Illustrated with a Computationally Designed Protein-Ligand Interaction.

    Science.gov (United States)

    Van Patten, William J; Walder, Robert; Adhikari, Ayush; Okoniewski, Stephen R; Ravichandran, Rashmi; Tinberg, Christine E; Baker, David; Perkins, Thomas T

    2018-01-05

    Quantifying the energy landscape underlying protein-ligand interactions leads to an enhanced understanding of molecular recognition. A powerful yet accessible single-molecule technique is atomic force microscopy (AFM)-based force spectroscopy, which generally yields the zero-force dissociation rate constant (k off ) and the distance to the transition state (Δx ≠ ). Here, we introduce an enhanced AFM assay and apply it to probe the computationally designed protein DIG10.3 binding to its target ligand, digoxigenin. Enhanced data quality enabled an analysis that yielded the height of the transition state (ΔG ≠ =6.3±0.2 kcal mol -1 ) and the shape of the energy barrier at the transition state (linear-cubic) in addition to the traditional parameters [k off (=4±0.1×10 -4  s -1 ) and Δx ≠ (=8.3±0.1 Å)]. We expect this automated and relatively rapid assay to provide a more complete energy landscape description of protein-ligand interactions and, more broadly, the diverse systems studied by AFM-based force spectroscopy. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Specific noncovalent interactions at protein-ligand interface: implications for rational drug design.

    Science.gov (United States)

    Zhou, P; Huang, J; Tian, F

    2012-01-01

    Specific noncovalent interactions that are indicative of attractive, directional intermolecular forces have always been of key interest to medicinal chemists in their search for the "glue" that holds drugs and their targets together. With the rapid increase in the number of solved biomolecular structures as well as the performance enhancement of computer hardware and software in recent years, it is now possible to give more comprehensive insight into the geometrical characteristics and energetic landscape of certain sophisticated noncovalent interactions present at the binding interface of protein receptors and small ligands based on accumulated knowledge gaining from the combination of two quite disparate but complementary approaches: crystallographic data analysis and quantum-mechanical ab initio calculation. In this perspective, we survey massive body of published works relating to structural characterization and theoretical investigation of three kinds of strong, specific, direct, enthalpy-driven intermolecular forces, including hydrogen bond, halogen bond and salt bridge, involved in the formation of protein-ligand complex architecture in order to characterize their biological functions in conferring affinity and specificity for ligand recognition by host protein. In particular, the biomedical implications of raised knowledge are discussed with respect to potential applications in rational drug design.

  19. Assessing protein-ligand docking for the binding of organometallic compounds to proteins.

    Science.gov (United States)

    Ortega-Carrasco, Elisabeth; Lledós, Agusti; Maréchal, Jean-Didier

    2014-01-30

    Organometallic compounds are increasingly used as molecular scaffolds in drug development projects; their structural and electronic properties offering novel opportunities in protein-ligand complementarities. Interestingly, while protein-ligand dockings have long become a spearhead in computer assisted drug design, no benchmarking nor optimization have been done for their use with organometallic compounds. Pursuing our efforts to model metal mediated recognition processes, we herein present a systematic study of the capabilities of the program GOLD to predict the interactions of protein with organometallic compounds. The study focuses on inert systems for which no alteration of the first coordination sphere of the metal occurs upon binding. Several scaffolds are used as test systems with different docking schemes and scoring functions. We conclude that ChemScore is the most robust scoring function with ASP and ChemPLP providing with good results too and GoldScore slightly underperforming. This study shows that current state-of-the-art protein-ligand docking techniques are reliable for the docking of inert organometallic compounds binding to protein. Copyright © 2013 Wiley Periodicals, Inc.

  20. Beyond the Matrix: The Many Non-ECM Ligands for Integrins

    Directory of Open Access Journals (Sweden)

    Bryce LaFoya

    2018-02-01

    Full Text Available The traditional view of integrins portrays these highly conserved cell surface receptors as mediators of cellular attachment to the extracellular matrix (ECM, and to a lesser degree, as coordinators of leukocyte adhesion to the endothelium. These canonical activities are indispensable; however, there is also a wide variety of integrin functions mediated by non-ECM ligands that transcend the traditional roles of integrins. Some of these unorthodox roles involve cell-cell interactions and are engaged to support immune functions such as leukocyte transmigration, recognition of opsonization factors, and stimulation of neutrophil extracellular traps. Other cell-cell interactions mediated by integrins include hematopoietic stem cell and tumor cell homing to target tissues. Integrins also serve as cell-surface receptors for various growth factors, hormones, and small molecules. Interestingly, integrins have also been exploited by a wide variety of organisms including viruses and bacteria to support infectious activities such as cellular adhesion and/or cellular internalization. Additionally, the disruption of integrin function through the use of soluble integrin ligands is a common strategy adopted by several parasites in order to inhibit blood clotting during hematophagy, or by venomous snakes to kill prey. In this review, we strive to go beyond the matrix and summarize non-ECM ligands that interact with integrins in order to highlight these non-traditional functions of integrins.