Analysis of immune activation and clinical events in acute infectious mononucleosis.

PubMed

Williams, Hilary; Macsween, Karen; McAulay, Karen; Higgins, Craig; Harrison, Nadine; Swerdlow, Anthony; Britton, Kate; Crawford, Dorothy

2004-07-01

The symptoms of infectious mononucleosis (IM) are thought to be caused by T cell activation and cytokine production. Surface lymphocyte activation marker (SLAM)-associated protein (SAP) regulates lymphocyte activation via signals from cell-surface CD244 (2B4) and SLAM (CD150). We followed T cell activation via this SAP/SLAM/CD244 pathway in IM and analyzed whether the results were associated with clinical severity. At diagnosis, SAP, SLAM, and CD244 were significantly up-regulated on CD4 and CD8 T cells; expression decreased during IM, but CD244 and SLAM levels remained higher on CD8 cells 40 days later. There were significantly more lymphocytes expressing CD8 and CD244/CD8 in patients with severe sore throat. The expression of CD8 alone and CD244 on CD8 cells correlated with increased virus load. We suggest that T cells expressing CD244 and SLAM are responsible for the clinical features of IM but that the control of activation is maintained by parallel increased expression of SAP.

VeroNectin-4 is a highly sensitive cell line that can be used for the isolation and titration of Peste des Petits Ruminants virus.

PubMed

Fakri, F; Elarkam, A; Daouam, S; Tadlaoui, K; Fassi-Fihri, O; Richardson, C D; Elharrak, M

2016-02-01

Peste des Petits Ruminants virus (PPRV) is a member of the Morbillivirus subgroup of the family Paramyxoviridae, and is one of the most contagious diseases of small ruminants throughout Africa and the rest of the world. Different cell lines have previously been used to isolate PPRV but with limited success. Thus, to improve the isolation of Morbilliviruses, human, canine, and goat homologues of the lymphocyte receptor signaling lymphocyte activation molecule (SLAM) have been introduced into cells that can support virus replication. However, the amino acid sequence of SLAM varies between species, and often requires adaptation of a particular virus to different versions of the receptor. The protein sequence of Nectin-4 is highly conserved between different mammals, which eliminate the need for receptor adaptation by the virus. Cell lines expressing Nectin-4 have previously been used to propagate measles and canine distemper viruses. In this study, we compared infections in Vero cells expressing canine SLAM (VeroDogSLAM) to those in Vero cells expressing Nectin-4 (VeroNectin-4), following inoculations with wild-type strains of PPRV. Virus isolation using VeroNectin-4 cells was successful with 23% of swabbed samples obtained from live infected animals, and was 89% effective using post-mortem tissues of infected sheep. By contrast, only 4.5% efficiency was observed from swab samples and 67% efficiency was obtained in virus isolation from post-mortem tissues using VeroDogSLAM cells. The average incubation period for virus recovery from post-mortem tissues was 3.4 days using VeroNectin-4 cells, compared with 5.5 days when using VeroDogSLAM cells. The virus titers of PPRV obtained from VeroNectin-4 cells were also higher than those derived from VeroDogSLAM cells. A comparison of the growth kinetics for PPRV in the two cell lines confirmed the superiority of VeroNectin-4 cells for PPR diagnostic purposes and vaccine virus titration. Copyright © 2015 Elsevier B.V. All rights reserved.

Lethal canine distemper virus outbreak in cynomolgus monkeys in Japan in 2008.

PubMed

Sakai, Kouji; Nagata, Noriyo; Ami, Yasushi; Seki, Fumio; Suzaki, Yuriko; Iwata-Yoshikawa, Naoko; Suzuki, Tadaki; Fukushi, Shuetsu; Mizutani, Tetsuya; Yoshikawa, Tomoki; Otsuki, Noriyuki; Kurane, Ichiro; Komase, Katsuhiro; Yamaguchi, Ryoji; Hasegawa, Hideki; Saijo, Masayuki; Takeda, Makoto; Morikawa, Shigeru

2013-01-01

Canine distemper virus (CDV) has recently expanded its host range to nonhuman primates. A large CDV outbreak occurred in rhesus monkeys at a breeding farm in Guangxi Province, China, in 2006, followed by another outbreak in rhesus monkeys at an animal center in Beijing in 2008. In 2008 in Japan, a CDV outbreak also occurred in cynomolgus monkeys imported from China. In that outbreak, 46 monkeys died from severe pneumonia during a quarantine period. A CDV strain (CYN07-dV) was isolated in Vero cells expressing dog signaling lymphocyte activation molecule (SLAM). Phylogenic analysis showed that CYN07-dV was closely related to the recent CDV outbreaks in China, suggesting continuing chains of CDV infection in monkeys. In vitro, CYN07-dV uses macaca SLAM and macaca nectin4 as receptors as efficiently as dog SLAM and dog nectin4, respectively. CYN07-dV showed high virulence in experimentally infected cynomolgus monkeys and excreted progeny viruses in oral fluid and feces. These data revealed that some of the CDV strains, like CYN07-dV, have the potential to cause acute systemic infection in monkeys.

The Receptor-Binding Site of the Measles Virus Hemagglutinin Protein Itself Constitutes a Conserved Neutralizing Epitope

PubMed Central

Ohno, Shinji; Sakai, Kouji; Ito, Yuri; Fukuhara, Hideo; Komase, Katsuhiro; Brindley, Melinda A.; Rota, Paul A.; Plemper, Richard K.; Maenaka, Katsumi; Takeda, Makoto

2013-01-01

Here, we provide direct evidence that the receptor-binding site of measles virus (MV) hemagglutinin protein itself forms an effective conserved neutralizing epitope (CNE). Several receptor-interacting residues constitute the CNE. Thus, viral escape from neutralization has to be associated with loss of receptor-binding activity. Since interactions with both the signaling lymphocyte activation molecule (SLAM) and nectin4 are critical for MV pathogenesis, its escape, which results from loss of receptor-binding activity, should not occur in nature. PMID:23283964

Structural basis of efficient contagion: measles variations on a theme by parainfluenza viruses.

PubMed

Mateo, Mathieu; Navaratnarajah, Chanakha K; Cattaneo, Roberto

2014-04-01

A quartet of attachment proteins and a trio of fusion protein subunits play the cell entry concert of parainfluenza viruses. While many of these viruses bind sialic acid to enter cells, wild type measles binds exclusively two tissue-specific proteins, the lymphatic receptor signaling lymphocytic activation molecule (SLAM), and the epithelial receptor nectin-4. SLAM binds near the stalk-head junction of the hemagglutinin. Nectin-4 binds a hydrophobic groove located between blades 4 and 5 of the hemagglutinin β-propeller head. The mutated vaccine strain hemagglutinin binds in addition the ubiquitous protein CD46, which explains attenuation. The measles virus entry concert has four movements. Andante misterioso: the virus takes over the immune system. Allegro con brio: it rapidly spreads in the upper airway's epithelia. 'Targeting' fugue: the versatile orchestra takes off. Presto furioso: the virus exits the host with thunder. Be careful: music is contagious. Copyright © 2014 Elsevier B.V. All rights reserved.

Slam Poetry: An Artistic Resistance toward Identity, Agency, and Activism

ERIC Educational Resources Information Center

Muhammad, Gholnecsar; Gonzalez, Lee

2016-01-01

In this essay, the authors present experiences as writers (poets), thinkers, and activists to explicate the literary genre of slam poetry and its affordances as an artistic resistance toward the end of identity, agency, and activism. These areas of development are critical for youth because they are beginning to be navigated and established during…

MonoSLAM: real-time single camera SLAM.

PubMed

Davison, Andrew J; Reid, Ian D; Molton, Nicholas D; Stasse, Olivier

2007-06-01

We present a real-time algorithm which can recover the 3D trajectory of a monocular camera, moving rapidly through a previously unknown scene. Our system, which we dub MonoSLAM, is the first successful application of the SLAM methodology from mobile robotics to the "pure vision" domain of a single uncontrolled camera, achieving real time but drift-free performance inaccessible to Structure from Motion approaches. The core of the approach is the online creation of a sparse but persistent map of natural landmarks within a probabilistic framework. Our key novel contributions include an active approach to mapping and measurement, the use of a general motion model for smooth camera movement, and solutions for monocular feature initialization and feature orientation estimation. Together, these add up to an extremely efficient and robust algorithm which runs at 30 Hz with standard PC and camera hardware. This work extends the range of robotic systems in which SLAM can be usefully applied, but also opens up new areas. We present applications of MonoSLAM to real-time 3D localization and mapping for a high-performance full-size humanoid robot and live augmented reality with a hand-held camera.

The adaptor protein SAP directly associates with PECAM-1 and regulates PECAM-1-mediated-cell adhesion in T-like cell lines.

PubMed

Proust, Richard; Crouin, Catherine; Gandji, Leslie Yewakon; Bertoglio, Jacques; Gesbert, Franck

2014-04-01

SAP is a small cytosolic adaptor protein expressed in hematopoietic lineages whose main function is to regulate intracellular signaling pathways induced by the triggering of members of the SLAM receptor family. In this paper, we have identified the adhesion molecule PECAM-1 as a new partner for SAP in a conditional yeast two-hybrid screen. PECAM-1 is an immunoglobulin-like molecule expressed by endothelial cells and leukocytes, which possesses both pro- and anti-inflammatory properties. However, little is known about PECAM-1 functions in T cells. We show that SAP directly and specifically interacts with the cytosolic tyrosine 686 of PECAM-1. We generated different T-like cell lines in which SAP or PECAM-1 are expressed or down modulated and we demonstrate that a diminished SAP expression correlates with a diminished PECAM-1-mediated adhesion. Although SAP has mainly been shown to associate with SLAM receptors, we evidence here that SAP is a new actor downstream of PECAM-1. Copyright © 2013 Elsevier Ltd. All rights reserved.

Review of ship slamming loads and responses

NASA Astrophysics Data System (ADS)

Wang, Shan; Guedes Soares, C.

2017-12-01

The paper presents an overview of studies of slamming on ship structures. This work focuses on the hull slamming, which is one of the most important types of slamming problems to be considered in the ship design process and the assessment of the ship safety. There are three main research aspects related to the hull slamming phenomenon, a) where and how often a slamming event occurs, b) slamming load prediction and c) structural response due to slamming loads. The approaches used in each aspect are reviewed and commented, together with the presentation of some typical results. The methodology, which combines the seakeeping analysis and slamming load prediction, is discussed for the global analysis of the hull slamming of a ship in waves. Some physical phenomena during the slamming event are discussed also. Recommendations for the future research and developments are made.

CRISPR-Mediated Triple Knockout of SLAMF1, SLAMF5 and SLAMF6 Supports Positive Signaling Roles in NKT Cell Development.

PubMed

Huang, Bonnie; Gomez-Rodriguez, Julio; Preite, Silvia; Garrett, Lisa J; Harper, Ursula L; Schwartzberg, Pamela L

2016-01-01

The SLAM family receptors contribute to diverse aspects of lymphocyte biology and signal via the small adaptor molecule SAP. Mutations affecting SAP lead to X-linked lymphoproliferative syndrome Type 1, a severe immunodysregulation characterized by fulminant mononucleosis, dysgammaglobulinemia, and lymphoproliferation/lymphomas. Patients and mice having mutations affecting SAP also lack germinal centers due to a defect in T:B cell interactions and are devoid of invariant NKT (iNKT) cells. However, which and how SLAM family members contribute to these phenotypes remains uncertain. Three SLAM family members: SLAMF1, SLAMF5 and SLAMF6, are highly expressed on T follicular helper cells and germinal center B cells. SLAMF1 and SLAMF6 are also implicated in iNKT development. Although individual receptor knockout mice have limited iNKT and germinal center phenotypes compared to SAP knockout mice, the generation of multi-receptor knockout mice has been challenging, due to the genomic linkage of the genes encoding SLAM family members. Here, we used Cas9/CRISPR-based mutagenesis to generate mutations simultaneously in Slamf1, Slamf5 and Slamf6. Genetic disruption of all three receptors in triple-knockout mice (TKO) did not grossly affect conventional T or B cell development and led to mild defects in germinal center formation post-immunization. However, the TKO worsened defects in iNKT cells development seen in SLAMF6 single gene-targeted mice, supporting data on positive signaling and potential redundancy between these receptors.

A survey of simultaneous localization and mapping on unstructured lunar complex environment

NASA Astrophysics Data System (ADS)

Wang, Yiqiao; Zhang, Wei; An, Pei

2017-10-01

Simultaneous localization and mapping (SLAM) technology is the key to realizing lunar rover's intelligent perception and autonomous navigation. It embodies the autonomous ability of mobile robot, and has attracted plenty of concerns of researchers in the past thirty years. Visual sensors are meaningful to SLAM research because they can provide a wealth of information. Visual SLAM uses merely images as external information to estimate the location of the robot and construct the environment map. Nowadays, SLAM technology still has problems when applied in large-scale, unstructured and complex environment. Based on the latest technology in the field of visual SLAM, this paper investigates and summarizes the SLAM technology using in the unstructured complex environment of lunar surface. In particular, we focus on summarizing and comparing the detection and matching of features of SIFT, SURF and ORB, in the meanwhile discussing their advantages and disadvantages. We have analyzed the three main methods: SLAM Based on Extended Kalman Filter, SLAM Based on Particle Filter and SLAM Based on Graph Optimization (EKF-SLAM, PF-SLAM and Graph-based SLAM). Finally, this article summarizes and discusses the key scientific and technical difficulties in the lunar context that Visual SLAM faces. At the same time, we have explored the frontier issues such as multi-sensor fusion SLAM and multi-robot cooperative SLAM technology. We also predict and prospect the development trend of lunar rover SLAM technology, and put forward some ideas of further research.

Visual EKF-SLAM from Heterogeneous Landmarks †

PubMed Central

Esparza-Jiménez, Jorge Othón; Devy, Michel; Gordillo, José L.

2016-01-01

Many applications require the localization of a moving object, e.g., a robot, using sensory data acquired from embedded devices. Simultaneous localization and mapping from vision performs both the spatial and temporal fusion of these data on a map when a camera moves in an unknown environment. Such a SLAM process executes two interleaved functions: the front-end detects and tracks features from images, while the back-end interprets features as landmark observations and estimates both the landmarks and the robot positions with respect to a selected reference frame. This paper describes a complete visual SLAM solution, combining both point and line landmarks on a single map. The proposed method has an impact on both the back-end and the front-end. The contributions comprehend the use of heterogeneous landmark-based EKF-SLAM (the management of a map composed of both point and line landmarks); from this perspective, the comparison between landmark parametrizations and the evaluation of how the heterogeneity improves the accuracy on the camera localization, the development of a front-end active-search process for linear landmarks integrated into SLAM and the experimentation methodology. PMID:27070602

A novel combined SLAM based on RBPF-SLAM and EIF-SLAM for mobile system sensing in a large scale environment.

PubMed

He, Bo; Zhang, Shujing; Yan, Tianhong; Zhang, Tao; Liang, Yan; Zhang, Hongjin

2011-01-01

Mobile autonomous systems are very important for marine scientific investigation and military applications. Many algorithms have been studied to deal with the computational efficiency problem required for large scale simultaneous localization and mapping (SLAM) and its related accuracy and consistency. Among these methods, submap-based SLAM is a more effective one. By combining the strength of two popular mapping algorithms, the Rao-Blackwellised particle filter (RBPF) and extended information filter (EIF), this paper presents a combined SLAM-an efficient submap-based solution to the SLAM problem in a large scale environment. RBPF-SLAM is used to produce local maps, which are periodically fused into an EIF-SLAM algorithm. RBPF-SLAM can avoid linearization of the robot model during operating and provide a robust data association, while EIF-SLAM can improve the whole computational speed, and avoid the tendency of RBPF-SLAM to be over-confident. In order to further improve the computational speed in a real time environment, a binary-tree-based decision-making strategy is introduced. Simulation experiments show that the proposed combined SLAM algorithm significantly outperforms currently existing algorithms in terms of accuracy and consistency, as well as the computing efficiency. Finally, the combined SLAM algorithm is experimentally validated in a real environment by using the Victoria Park dataset.

Mice Lacking the SLAM Family Member CD84 Display Unaltered Platelet Function in Hemostasis and Thrombosis

PubMed Central

Hofmann, Sebastian; Braun, Attila; Pozgaj, Rastislav; Morowski, Martina; Vögtle, Timo; Nieswandt, Bernhard

2014-01-01

Background Platelets are anuclear cell fragments derived from bone marrow megakaryocytes that safeguard vascular integrity by forming thrombi at sites of vascular injury. Although the early events of thrombus formation—platelet adhesion and aggregation—have been intensively studied, less is known about the mechanisms and receptors that stabilize platelet-platelet interactions once a thrombus has formed. One receptor that has been implicated in this process is the signaling lymphocyte activation molecule (SLAM) family member CD84, which can undergo homophilic interactions and becomes phosphorylated upon platelet aggregation. Objective The role of CD84 in platelet physiology and thrombus formation was investigated in CD84-deficient mice. Methods and Results We generated CD84-deficient mice and analyzed their platelets in vitro and in vivo. Cd84−/− platelets exhibited normal activation and aggregation responses to classical platelet agonists. Furthermore, CD84 deficiency did not affect integrin-mediated clot retraction and spreading of activated platelets on fibrinogen. Notably, also the formation of stable three-dimensional thrombi on collagen-coated surfaces under flow ex vivo was unaltered in the blood of Cd84−/− mice. In vivo, Cd84−/− mice exhibited unaltered hemostatic function and arterial thrombus formation. Conclusion These results show that CD84 is dispensable for thrombus formation and stabilization, indicating that its deficiency may be functionally compensated by other receptors or that it may be important for platelet functions different from platelet-platelet interactions. PMID:25551754

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells

PubMed Central

2017-01-01

ABSTRACT Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein–Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8+ T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a−/− CD8+ T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a−/− CD8+ T cells responded equivalently to wild-type CD8+ T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8+ T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8+ T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8+ T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas. PMID:28344876

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells.

PubMed

Huang, Yu-Hsuan; Tsai, Kevin; Tan, Sara Y; Kang, Sohyeong; Ford, Mandy L; Harder, Kenneth W; Priatel, John J

2017-01-01

Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8 + T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a - / - CD8 + T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a - / - CD8 + T cells responded equivalently to wild-type CD8 + T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8 + T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8 + T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8 + T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.

The 2007 National Federation of the Blind Youth Slam: Making Astronomy Accessible to Students Who are Blind

NASA Astrophysics Data System (ADS)

Grice, Noreen A.

2008-05-01

In the summer of 2007, nearly two hundred blind and visually impaired high school students participated in a weeklong enrichment program at Johns Hopkins University called the National Federation of the Blind Youth Slam. They spent four days participating in hands-on science and engineering classes and exploring careers previously thought inaccessible to those without sight. The students were separated into "tracks” with each group focusing on a different field. Want to know what happened in the astronomy track? Come by this paper and see examples of accessible astronomy activities, including accessible star parties, from the Youth Slam!

Autonomous Navigation for Autonomous Underwater Vehicles Based on Information Filters and Active Sensing

PubMed Central

He, Bo; Zhang, Hongjin; Li, Chao; Zhang, Shujing; Liang, Yan; Yan, Tianhong

2011-01-01

This paper addresses an autonomous navigation method for the autonomous underwater vehicle (AUV) C-Ranger applying information-filter-based simultaneous localization and mapping (SLAM), and its sea trial experiments in Tuandao Bay (Shangdong Province, P.R. China). Weak links in the information matrix in an extended information filter (EIF) can be pruned to achieve an efficient approach-sparse EIF algorithm (SEIF-SLAM). All the basic update formulae can be implemented in constant time irrespective of the size of the map; hence the computational complexity is significantly reduced. The mechanical scanning imaging sonar is chosen as the active sensing device for the underwater vehicle, and a compensation method based on feedback of the AUV pose is presented to overcome distortion of the acoustic images due to the vehicle motion. In order to verify the feasibility of the navigation methods proposed for the C-Ranger, a sea trial was conducted in Tuandao Bay. Experimental results and analysis show that the proposed navigation approach based on SEIF-SLAM improves the accuracy of the navigation compared with conventional method; moreover the algorithm has a low computational cost when compared with EKF-SLAM. PMID:22346682

Autonomous navigation for autonomous underwater vehicles based on information filters and active sensing.

PubMed

He, Bo; Zhang, Hongjin; Li, Chao; Zhang, Shujing; Liang, Yan; Yan, Tianhong

2011-01-01

This paper addresses an autonomous navigation method for the autonomous underwater vehicle (AUV) C-Ranger applying information-filter-based simultaneous localization and mapping (SLAM), and its sea trial experiments in Tuandao Bay (Shangdong Province, P.R. China). Weak links in the information matrix in an extended information filter (EIF) can be pruned to achieve an efficient approach-sparse EIF algorithm (SEIF-SLAM). All the basic update formulae can be implemented in constant time irrespective of the size of the map; hence the computational complexity is significantly reduced. The mechanical scanning imaging sonar is chosen as the active sensing device for the underwater vehicle, and a compensation method based on feedback of the AUV pose is presented to overcome distortion of the acoustic images due to the vehicle motion. In order to verify the feasibility of the navigation methods proposed for the C-Ranger, a sea trial was conducted in Tuandao Bay. Experimental results and analysis show that the proposed navigation approach based on SEIF-SLAM improves the accuracy of the navigation compared with conventional method; moreover the algorithm has a low computational cost when compared with EKF-SLAM.

AUV SLAM and Experiments Using a Mechanical Scanning Forward-Looking Sonar

PubMed Central

He, Bo; Liang, Yan; Feng, Xiao; Nian, Rui; Yan, Tianhong; Li, Minghui; Zhang, Shujing

2012-01-01

Navigation technology is one of the most important challenges in the applications of autonomous underwater vehicles (AUVs) which navigate in the complex undersea environment. The ability of localizing a robot and accurately mapping its surroundings simultaneously, namely the simultaneous localization and mapping (SLAM) problem, is a key prerequisite of truly autonomous robots. In this paper, a modified-FastSLAM algorithm is proposed and used in the navigation for our C-Ranger research platform, an open-frame AUV. A mechanical scanning imaging sonar is chosen as the active sensor for the AUV. The modified-FastSLAM implements the update relying on the on-board sensors of C-Ranger. On the other hand, the algorithm employs the data association which combines the single particle maximum likelihood method with modified negative evidence method, and uses the rank-based resampling to overcome the particle depletion problem. In order to verify the feasibility of the proposed methods, both simulation experiments and sea trials for C-Ranger are conducted. The experimental results show the modified-FastSLAM employed for the navigation of the C-Ranger AUV is much more effective and accurate compared with the traditional methods. PMID:23012549

AUV SLAM and experiments using a mechanical scanning forward-looking sonar.

PubMed

He, Bo; Liang, Yan; Feng, Xiao; Nian, Rui; Yan, Tianhong; Li, Minghui; Zhang, Shujing

2012-01-01

Navigation technology is one of the most important challenges in the applications of autonomous underwater vehicles (AUVs) which navigate in the complex undersea environment. The ability of localizing a robot and accurately mapping its surroundings simultaneously, namely the simultaneous localization and mapping (SLAM) problem, is a key prerequisite of truly autonomous robots. In this paper, a modified-FastSLAM algorithm is proposed and used in the navigation for our C-Ranger research platform, an open-frame AUV. A mechanical scanning imaging sonar is chosen as the active sensor for the AUV. The modified-FastSLAM implements the update relying on the on-board sensors of C-Ranger. On the other hand, the algorithm employs the data association which combines the single particle maximum likelihood method with modified negative evidence method, and uses the rank-based resampling to overcome the particle depletion problem. In order to verify the feasibility of the proposed methods, both simulation experiments and sea trials for C-Ranger are conducted. The experimental results show the modified-FastSLAM employed for the navigation of the C-Ranger AUV is much more effective and accurate compared with the traditional methods.

Cetacean Morbillivirus: Current Knowledge and Future Directions

PubMed Central

Van Bressem, Marie-Françoise; Duignan, Pádraig J.; Banyard, Ashley; Barbieri, Michelle; Colegrove, Kathleen M; De Guise, Sylvain; Di Guardo, Giovanni; Dobson, Andrew; Domingo, Mariano; Fauquier, Deborah; Fernandez, Antonio; Goldstein, Tracey; Grenfell, Bryan; Groch, Kátia R.; Gulland, Frances; Jensen, Brenda A; Jepson, Paul D; Hall, Ailsa; Kuiken, Thijs; Mazzariol, Sandro; Morris, Sinead E; Nielsen, Ole; Raga, Juan A; Rowles, Teresa K; Saliki, Jeremy; Sierra, Eva; Stephens, Nahiid; Stone, Brett; Tomo, Ikuko; Wang, Jianning; Waltzek, Thomas; Wellehan, James FX

2014-01-01

We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported. PMID:25533660

Slamming Arkansas Schools!

ERIC Educational Resources Information Center

Scott, W. Clayton

2010-01-01

In this article, the author, a poet and teaching artist, shares how he successfully brought slam poetry to College Hill Middle School in Texarkana, Arkansas. In 2001 he discovered slam poetry--a poetry-reading format in which poets compete in dramatic readings of their works--and went to Slam Nationals in Seattle on the Arkansas slam team. He…

Systemic lupus erythematosus in a multiethnic cohort (LUMINA): XXIX. Elevation of erythrocyte sedimentation rate is associated with disease activity and damage accrual.

PubMed

Vilá, Luis M; Alarcón, Graciela S; McGwin, Gerald; Bastian, Holly M; Fessler, Barri J; Reveille, John D

2005-11-01

To determine if different categories of erythrocyte sedimentation rate (ESR) elevation are associated with disease activity and/or damage in systemic lupus erythematosus (SLE). We studied 2317 study visits in 553 SLE patients (> or = 4 American College of Rheumatology criteria, < or = 5 years' disease duration at enrollment) from a multiethnic (Hispanic, African American, and Caucasian) longitudinal study of outcome. A study visit was done every 6 months for the first year and annually thereafter. Erythrocyte sedimentation rate (ESR) was measured using the Westergren method; results were expressed in 4 categories: < 25 (normal), 25-50 (mild elevation), 51-75 (moderate elevation), and > 75 (marked elevation) mm/h. Anti-dsDNA antibodies were measured at enrollment with the Crithidia luciliae assay. Disease activity was assessed with the Systemic Lupus Activity Measure (SLAM) and the Physician's Global Assessment (PGA). Because ESR is one of the measures evaluated in the SLAM, it was excluded from the total SLAM score. Disease damage was assessed with the Systemic Lupus International Collaborating Clinics damage index (SDI). The relationship between the SLAM (total and PGA) and SDI scores (at baseline and for all visits) and anti-dsDNA antibodies (at enrollment) with ESR was examined by univariable and generalized estimating equation (GEE) regression analyses. Ethnicity, age, and sex were entered in all regression models. The cohort consisted of 89.7% women with mean age 36.8 (SD 12.6) years and disease duration 4.6 (SD 3.2) years. GEE analyses showed that increasing levels of ESR and anti-dsDNA antibody positivity were independently associated with SLAM and PGA scores, at enrollment and for all visits. Overall, the associations of ESR with SLAM and PGA scores were stronger than for the presence of anti-dsDNA antibodies. At baseline, there was no relationship of ESR elevation or anti-dsDNA positivity with SDI scores. However, when all visits were studied, moderate and marked elevations of ESR were independently associated with SDI scores. Mild, moderate, and marked ESR elevations are strongly associated with disease activity in SLE. Moderate and marked ESR elevations are also associated with damage accrual. These associations are stronger than those for the presence of anti-dsDNA antibodies. Our data suggest that ESR could be used to assess disease activity and predict organ/system damage in a relatively rapid and inexpensive manner in SLE.

Sensor fusion of monocular cameras and laser rangefinders for line-based Simultaneous Localization and Mapping (SLAM) tasks in autonomous mobile robots.

PubMed

Zhang, Xinzheng; Rad, Ahmad B; Wong, Yiu-Kwong

2012-01-01

This paper presents a sensor fusion strategy applied for Simultaneous Localization and Mapping (SLAM) in dynamic environments. The designed approach consists of two features: (i) the first one is a fusion module which synthesizes line segments obtained from laser rangefinder and line features extracted from monocular camera. This policy eliminates any pseudo segments that appear from any momentary pause of dynamic objects in laser data. (ii) The second characteristic is a modified multi-sensor point estimation fusion SLAM (MPEF-SLAM) that incorporates two individual Extended Kalman Filter (EKF) based SLAM algorithms: monocular and laser SLAM. The error of the localization in fused SLAM is reduced compared with those of individual SLAM. Additionally, a new data association technique based on the homography transformation matrix is developed for monocular SLAM. This data association method relaxes the pleonastic computation. The experimental results validate the performance of the proposed sensor fusion and data association method.

Three main paradigms of simultaneous localization and mapping (SLAM) problem

NASA Astrophysics Data System (ADS)

Imani, Vandad; Haataja, Keijo; Toivanen, Pekka

2018-04-01

Simultaneous Localization and Mapping (SLAM) is one of the most challenging research areas within computer and machine vision for automated scene commentary and explanation. The SLAM technique has been a developing research area in the robotics context during recent years. By utilizing the SLAM method robot can estimate the different positions of the robot at the distinct points of time which can indicate the trajectory of robot as well as generate a map of the environment. SLAM has unique traits which are estimating the location of robot and building a map in the various types of environment. SLAM is effective in different types of environment such as indoor, outdoor district, Air, Underwater, Underground and Space. Several approaches have been investigated to use SLAM technique in distinct environments. The purpose of this paper is to provide an accurate perceptive review of case history of SLAM relied on laser/ultrasonic sensors and camera as perception input data. In addition, we mainly focus on three paradigms of SLAM problem with all its pros and cons. In the future, use intelligent methods and some new idea will be used on visual SLAM to estimate the motion intelligent underwater robot and building a feature map of marine environment.

Curveslam: Utilizing Higher Level Structure In Stereo Vision-Based Navigation

DTIC Science & Technology

2012-01-01

consider their applica- tion to SLAM . The work of [31] [32] develops a spline-based SLAM framework, but this is only for application to LIDAR -based SLAM ...Existing approaches to visual Simultaneous Localization and Mapping ( SLAM ) typically utilize points as visual feature primitives to represent landmarks...regions of interest. Further, previous SLAM techniques that propose the use of higher level structures often place constraints on the environment, such as

Current state of the art of vision based SLAM

NASA Astrophysics Data System (ADS)

Muhammad, Naveed; Fofi, David; Ainouz, Samia

2009-02-01

The ability of a robot to localise itself and simultaneously build a map of its environment (Simultaneous Localisation and Mapping or SLAM) is a fundamental characteristic required for autonomous operation of the robot. Vision Sensors are very attractive for application in SLAM because of their rich sensory output and cost effectiveness. Different issues are involved in the problem of vision based SLAM and many different approaches exist in order to solve these issues. This paper gives a classification of state-of-the-art vision based SLAM techniques in terms of (i) imaging systems used for performing SLAM which include single cameras, stereo pairs, multiple camera rigs and catadioptric sensors, (ii) features extracted from the environment in order to perform SLAM which include point features and line/edge features, (iii) initialisation of landmarks which can either be delayed or undelayed, (iv) SLAM techniques used which include Extended Kalman Filtering, Particle Filtering, biologically inspired techniques like RatSLAM, and other techniques like Local Bundle Adjustment, and (v) use of wheel odometry information. The paper also presents the implementation and analysis of stereo pair based EKF SLAM for synthetic data. Results prove the technique to work successfully in the presence of considerable amounts of sensor noise. We believe that state of the art presented in the paper can serve as a basis for future research in the area of vision based SLAM. It will permit further research in the area to be carried out in an efficient and application specific way.

Robot-Beacon Distributed Range-Only SLAM for Resource-Constrained Operation

PubMed Central

Torres-González, Arturo; Martínez-de Dios, Jose Ramiro; Ollero, Anibal

2017-01-01

This work deals with robot-sensor network cooperation where sensor nodes (beacons) are used as landmarks for Range-Only (RO) Simultaneous Localization and Mapping (SLAM). Most existing RO-SLAM techniques consider beacons as passive devices disregarding the sensing, computational and communication capabilities with which they are actually endowed. SLAM is a resource-demanding task. Besides the technological constraints of the robot and beacons, many applications impose further resource consumption limitations. This paper presents a scalable distributed RO-SLAM scheme for resource-constrained operation. It is capable of exploiting robot-beacon cooperation in order to improve SLAM accuracy while meeting a given resource consumption bound expressed as the maximum number of measurements that are integrated in SLAM per iteration. The proposed scheme combines a Sparse Extended Information Filter (SEIF) SLAM method, in which each beacon gathers and integrates robot-beacon and inter-beacon measurements, and a distributed information-driven measurement allocation tool that dynamically selects the measurements that are integrated in SLAM, balancing uncertainty improvement and resource consumption. The scheme adopts a robot-beacon distributed approach in which each beacon participates in the selection, gathering and integration in SLAM of robot-beacon and inter-beacon measurements, resulting in significant estimation accuracies, resource-consumption efficiency and scalability. It has been integrated in an octorotor Unmanned Aerial System (UAS) and evaluated in 3D SLAM outdoor experiments. The experimental results obtained show its performance and robustness and evidence its advantages over existing methods. PMID:28425946

Robot-Beacon Distributed Range-Only SLAM for Resource-Constrained Operation.

PubMed

Torres-González, Arturo; Martínez-de Dios, Jose Ramiro; Ollero, Anibal

2017-04-20

This work deals with robot-sensor network cooperation where sensor nodes (beacons) are used as landmarks for Range-Only (RO) Simultaneous Localization and Mapping (SLAM). Most existing RO-SLAM techniques consider beacons as passive devices disregarding the sensing, computational and communication capabilities with which they are actually endowed. SLAM is a resource-demanding task. Besides the technological constraints of the robot and beacons, many applications impose further resource consumption limitations. This paper presents a scalable distributed RO-SLAM scheme for resource-constrained operation. It is capable of exploiting robot-beacon cooperation in order to improve SLAM accuracy while meeting a given resource consumption bound expressed as the maximum number of measurements that are integrated in SLAM per iteration. The proposed scheme combines a Sparse Extended Information Filter (SEIF) SLAM method, in which each beacon gathers and integrates robot-beacon and inter-beacon measurements, and a distributed information-driven measurement allocation tool that dynamically selects the measurements that are integrated in SLAM, balancing uncertainty improvement and resource consumption. The scheme adopts a robot-beacon distributed approach in which each beacon participates in the selection, gathering and integration in SLAM of robot-beacon and inter-beacon measurements, resulting in significant estimation accuracies, resource-consumption efficiency and scalability. It has been integrated in an octorotor Unmanned Aerial System (UAS) and evaluated in 3D SLAM outdoor experiments. The experimental results obtained show its performance and robustness and evidence its advantages over existing methods.

Full particle simulations of short large-amplitude magnetic structures (SLAMS) in quasi-parallel shocks

NASA Astrophysics Data System (ADS)

Tsubouchi, K.; LembèGe, B.

2004-02-01

Dynamics of SLAMS (short large-amplitude magnetic structures) is investigated by the use of one-dimensional, full particle electromagnetic simulations. As previous hybrid simulations and analysis of experimental observations suggested, present results confirm that the SLAMS patterns result from the steepening of long wavelength magnetosonic waves which are excited by diffuse ions (representing the field-aligned reflected ion beam) interacting with the upstream ambient plasma. Five successive phases have been identified in the SLAMS dynamics: ULF wave growth and symmetric, asymmetric, spiky, and late SLAMS. The present accessibility to high-resolution (electron) scales leads to the following new features: (1) the leading edge of the SLAMS steepens over a spatial scale from which a large-amplitude whistler precursor is emitted; (2) this whistler departs from the SLAMS edge and behaves as a new shock front; (3) the spiky SLAMS phase is characterized by the build-up of a strong spiky electrostatic field (its width is about 0.5 ion inertial length) within the whistler precursor and is intermittent with a lifetime less than one inverse ion gyroperiod; (4) the new shock front suffers a local self-reformation typical of a quasi-perpendicular shock in supercritical regime during the late-SLAMS phase. The features of the spiky SLAMS phase can be used as a typical signature in the time history of the SLAMS dynamics. Spatial/time scales of SLAMS have been measured throughout the different phases and are found in good agreement with results issued from previous hybrid simulations and with experimental measurements made by AMPTE UKS/IRM satellites; these are also compared with recent results from Cluster-2 space mission.

Slam Poetry and Cultural Experience for Children

ERIC Educational Resources Information Center

Boudreau, Kathryn E.

2009-01-01

Slam poetry, being not just recitation or memorization, affords children the opportunity to express their own personal cultural experiences and values. Slam is a spoken word performance; a competition among poets. Audience commentary is ongoing during the performance and vigorous audience participation is essential in a slam format. The founders…

Development of Murine Lupus Involves the Combined Genetic Contribution of the SLAM and FcγR Intervals within the Nba2 Autoimmune Susceptibility Locus

PubMed Central

Jørgensen, Trine N.; Alfaro, Jennifer; Enriquez, Hilda L.; Jiang, Chao; Loo, William M.; Atencio, Stephanie; Bupp, Melanie R. Gubbels; Mailloux, Christina M.; Metzger, Troy; Flannery, Shannon; Rozzo, Stephen J.; Kotzin, Brian L.; Rosemblatt, Mario; Bono, María Rosa; Erickson, Loren D.

2010-01-01

Autoantibodies are of central importance in the pathogenesis of Ab-mediated autoimmune disorders. The murine lupus susceptibility locus Nba2 on chromosome 1 and the syntenic human locus are associated with a loss of immune tolerance that leads to antinuclear Ab production. To identify gene intervals within Nba2 that control the development of autoantibody-producing B cells and to determine the cellular components through which Nba2 genes accomplish this, we generated congenic mice expressing various Nba2 intervals where genes for the FcγR, SLAM, and IFN-inducible families are encoded. Analysis of congenic strains demonstrated that the FcγR and SLAM intervals independently controlled the severity of autoantibody production and renal disease, yet are both required for lupus susceptibility. Deregulated homeostasis of terminally differentiated B cells was found to be controlled by the FcγR interval where FcγRIIb-mediated apoptosis of germinal center B cells and plasma cells was impaired. Increased numbers of activated plasmacytoid dendritic cells that were distinctly CD19+ and promoted plasma cell differentiation via the proinflammatory cytokines IL-10 and IFNα were linked to the SLAM interval. These findings suggest that SLAM and FcγR intervals act cooperatively to influence the clinical course of disease through supporting the differentiation and survival of autoantibody-producing cells. PMID:20018631

Characterization of a new disease-causing mutation of SH2D1A in a family with X-linked lymphoproliferative disease.

PubMed

Erdõs, Melinda; Uzvölgyi, Eva; Nemes, Zoltán; Török, Olga; Rákóczi, Eva; Went-Sümegi, Nils; Sümegi, János; Maródi, László

2005-05-01

Males with an expressed mutation in the SH2D1A gene that encodes an SH2 domain protein named SH2D1A or SAP (NP_002342; signaling lymphocyte activating molecule [SLAM]-associated protein), have an X-linked syndrome characterized by an increased vulnerability to infection with Epstein-Barr virus (EBV). We evaluated two related male patients with fatal infectious mononucleosis (FIM) and mutation in the SH2D1A gene. Sequence analysis revealed a hemizygous c.47G>A mutation in one of the patients, and heterozygosity for this mutation in the genomic DNA from his mother and maternal grandmother. This mutation resulted in p.G16D amino acid change in the sequence of the SAP protein. To analyze the effect of this missense mutation on protein function cDNA was generated by site-directed mutagenesis and expressed in COS cells. We found that half-life of the p.G16D protein was comparable to that of wild type SAP. However, the mutant protein was defective in binding to its physiological ligands SLAM and 2B4. These results suggest that a defect in ligand binding contributes to the loss of function of the SAP protein in patients carrying p.G16D mutation.

Slamming: Recent Progress in the Evaluation of Impact Pressures

NASA Astrophysics Data System (ADS)

Dias, Frédéric; Ghidaglia, Jean-Michel

2018-01-01

Slamming, the violent impact between a liquid and solid, has been known to be important for a long time in the ship hydrodynamics community. More recently, applications ranging from the transport of liquefied natural gas (LNG) in LNG carriers to the harvesting of wave energy with oscillating wave surge converters have led to renewed interest in the topic. The main reason for this renewed interest is that the extreme impact pressures generated during slamming can affect the integrity of the structures involved. Slamming fluid mechanics is challenging to describe, as much from an experimental viewpoint as from a numerical viewpoint, because of the large span of spatial and temporal scales involved. Even the physical mechanisms of slamming are challenging: What physical phenomena must be included in slamming models? An important issue deals with the practical modeling of slamming: Are there any simple models available? Are numerical models viable? What are the consequences for the design of structures? This article describes the loading processes involved in slamming, offers state-of-the-art results, and highlights unresolved issues worthy of further research.

Evaluating quantitative and conceptual models of speech production: how does SLAM fare?

PubMed

Walker, Grant M; Hickok, Gregory

2016-04-01

In a previous publication, we presented a new computational model called SLAM (Walker & Hickok, Psychonomic Bulletin & Review doi: 10.3758/s13423-015-0903 ), based on the hierarchical state feedback control (HSFC) theory (Hickok Nature Reviews Neuroscience, 13(2), 135-145, 2012). In his commentary, Goldrick (Psychonomic Bulletin & Review doi: 10.3758/s13423-015-0946-9 ) claims that SLAM does not represent a theoretical advancement, because it cannot be distinguished from an alternative lexical + postlexical (LPL) theory proposed by Goldrick and Rapp (Cognition, 102(2), 219-260, 2007). First, we point out that SLAM implements a portion of a conceptual model (HSFC) that encompasses LPL. Second, we show that SLAM accounts for a lexical bias present in sound-related errors that LPL does not explain. Third, we show that SLAM's explanatory advantage is not a result of approximating the architectural or computational assumptions of LPL, since an implemented version of LPL fails to provide the same fit improvements as SLAM. Finally, we show that incorporating a mechanism that violates some core theoretical assumptions of LPL-making it more like SLAM in terms of interactivity-allows the model to capture some of the same effects as SLAM. SLAM therefore provides new modeling constraints regarding interactions among processing levels, while also elaborating on the structure of the phonological level. We view this as evidence that an integration of psycholinguistic, neuroscience, and motor control approaches to speech production is feasible and may lead to substantial new insights.

Magnetic resonance Spectroscopy with Linear Algebraic Modeling (SLAM) for higher speed and sensitivity

PubMed Central

Zhang, Yi; Gabr, Refaat E.; Schär, Michael; Weiss, Robert G.; Bottomley, Paul A.

2012-01-01

Speed and signal-to-noise ratio (SNR) are critical for localized magnetic resonance spectroscopy (MRS) of low-concentration metabolites. Matching voxels to anatomical compartments a priori yields better SNR than the spectra created by summing signals from constituent chemical-shift-imaging (CSI) voxels post-acquisition. Here, a new method of localized Spectroscopy using Linear Algebraic Modeling (SLAM) is presented, that can realize this additional SNR gain. Unlike prior methods, SLAM generates spectra from C signal-generating anatomic compartments utilizing a CSI sequence wherein essentially only the C central k-space phase-encoding gradient steps with highest SNR are retained. After MRI-based compartment segmentation, the spectra are reconstructed by solving a sub-set of linear simultaneous equations from the standard CSI algorithm. SLAM is demonstrated with one-dimensional CSI surface coil phosphorus MRS in phantoms, the human leg and the heart on a 3T clinical scanner. Its SNR performance, accuracy, sensitivity to registration errors and inhomogeneity, are evaluated. Compared to one-dimensional CSI, SLAM yielded quantitatively the same results 4-times faster in 24 cardiac patients and healthy subjects. SLAM is further extended with fractional phase-encoding gradients that optimize SNR and/or minimize both inter- and intra-compartmental contamination. In proactive cardiac phosphorus MRS of 6 healthy subjects, both SLAM and fractional-SLAM (fSLAM) produced results indistinguishable from CSI while preserving SNR gains of 36–45% in the same scan-time. Both SLAM and fSLAM are simple to implement and reduce the minimum scan-time for CSI, which otherwise limits the translation of higher SNR achievable at higher field strengths to faster scanning. PMID:22578557

Effect of hydroxychloroquine treatment on pro-inflammatory cytokines and disease activity in SLE patients: data from LUMINA (LXXV), a multiethnic US cohort

PubMed Central

Willis, R; Seif, AM; McGwin, G; Martinez-Martinez, LA; González, EB; Dang, N; Papalardo, E; Liu, J; Vilá, LM; Reveille, JD; Alarcón, GS; Pierangeli, SS

2013-01-01

Objective We sought to determine the effect of hydroxychloroquine therapy on the levels proinflammatory/prothrombotic markers and disease activity scores in patients with systemic lupus erythematosus (SLE) in a multiethnic, multi-center cohort (LUMINA). Methods Plasma/serum samples from SLE patients (n=35) were evaluated at baseline and after hydroxychloroquine treatment. Disease activity was assessed using SLAM-R scores. Interferon (IFN)-α2, interleukin (IL)-1β, IL-6, IL-8, inducible protein (IP)-10, monocyte chemotactic protein-1, tumor necrosis factor (TNF)-α and soluble CD40 ligand (sCD40L) levels were determined by a multiplex immunoassay. Anticardiolipin antibodies were evaluated using ELISA assays. Thirty-two frequency-matched plasma/serum samples from healthy donors were used as controls. Results Levels of IL-6, IP-10, sCD40L, IFN-α and TNF-α were significantly elevated in SLE patients versus controls. There was a positive but moderate correlation between SLAM-R scores at baseline and levels of IFN-α (p=0.0546). Hydroxychloroquine therapy resulted in a significant decrease in SLAM-R scores (p=0.0157), and the decrease in SLAM-R after hydroxychloroquine therapy strongly correlated with decreases in IFN-α (p=0.0087). Conclusions Hydroxychloroquine therapy resulted in significant clinical improvement in SLE patients, which strongly correlated with reductions in IFN-α levels. This indicates an important role for the inhibition of endogenous TLR activation in the action of hydroxychloroquine in SLE and provides additional evidence for the importance of type I interferons in the pathogenesis of SLE. This study underscores the use of hydroxychloroquine in the treatment of SLE. PMID:22343096

Associated factors and impact of myocarditis in patients with SLE from LUMINA, a multiethnic US cohort (LV). [corrected].

PubMed

Apte, M; McGwin, G; Vilá, L M; Kaslow, R A; Alarcón, G S; Reveille, J D

2008-03-01

To examine the factors associated with myocarditis and its impact on disease outcomes in SLE patients. SLE patients aged > or = 16 yrs, disease duration < or = 5 yrs from LUMINA (LUpus in Minorities: NAture vs nurture), a multiethnic US cohort, were studied. Myocarditis was defined as per the category 3 of the pericarditis/myocarditis item of the SLAM-Revised (SLAM-R). Patients with concurrent pericardial involvement were excluded. Patients with myocarditis were compared with those without myocarditis or its sequelae in the preceding year. The association between myocarditis and baseline variables (T(0)) was first examined. The impact of myocarditis on disease activity over time (SLAM-R), damage accrual [SLICC Damage Index (SDI)] at last visit (T(L)) and mortality was evaluated. Fifty-three of the 496 patients studied had myocarditis. African American ethnicity [Odds ratio (OR) = 12.6; 95% CI 1.6, 97.8] and SLAM-R at diagnosis (OR = 1.1, 95% CI 1.0, 1.1) were significantly and independently associated with myocarditis. Myocarditis did not predict disease activity over time, but approached significance as a predictor of SDI at T(L) in multivariable analyses P = 0.051. Kaplan-Meier curves indicated that myocarditis was associated with shorter survival (log-rank = 4.87, P = 0.02), particularly in patients with > or = 5 yrs disease; however, myocarditis was not retained in the Cox proportional hazards regression model. Ethnicity and disease activity at diagnosis were associated with the occurrence of myocarditis in SLE. Myocarditis did not significantly impact on disease activity over time, but impacts some on damage accrual and survival, reflecting overall the more severe disease those patients experience.

Temporally Scalable Visual SLAM using a Reduced Pose Graph

DTIC Science & Technology

2012-05-25

m b r i d g e , m a 0 213 9 u s a — w w w. c s a i l . m i t . e d u MIT-CSAIL-TR-2012-013 May 25, 2012 Temporally Scalable Visual SLAM using a...00-00-2012 4. TITLE AND SUBTITLE Temporally Scalable Visual SLAM using a Reduced Pose Graph 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...demonstrate a system for temporally scalable visual SLAM using a reduced pose graph representation. Unlike previous visual SLAM approaches that use

AEKF-SLAM: A New Algorithm for Robotic Underwater Navigation

PubMed Central

Yuan, Xin; Martínez-Ortega, José-Fernán; Fernández, José Antonio Sánchez; Eckert, Martina

2017-01-01

In this work, we focus on key topics related to underwater Simultaneous Localization and Mapping (SLAM) applications. Moreover, a detailed review of major studies in the literature and our proposed solutions for addressing the problem are presented. The main goal of this paper is the enhancement of the accuracy and robustness of the SLAM-based navigation problem for underwater robotics with low computational costs. Therefore, we present a new method called AEKF-SLAM that employs an Augmented Extended Kalman Filter (AEKF)-based SLAM algorithm. The AEKF-based SLAM approach stores the robot poses and map landmarks in a single state vector, while estimating the state parameters via a recursive and iterative estimation-update process. Hereby, the prediction and update state (which exist as well in the conventional EKF) are complemented by a newly proposed augmentation stage. Applied to underwater robot navigation, the AEKF-SLAM has been compared with the classic and popular FastSLAM 2.0 algorithm. Concerning the dense loop mapping and line mapping experiments, it shows much better performances in map management with respect to landmark addition and removal, which avoid the long-term accumulation of errors and clutters in the created map. Additionally, the underwater robot achieves more precise and efficient self-localization and a mapping of the surrounding landmarks with much lower processing times. Altogether, the presented AEKF-SLAM method achieves reliably map revisiting, and consistent map upgrading on loop closure. PMID:28531135

Comparative analysis of ROS-based monocular SLAM methods for indoor navigation

NASA Astrophysics Data System (ADS)

Buyval, Alexander; Afanasyev, Ilya; Magid, Evgeni

2017-03-01

This paper presents a comparison of four most recent ROS-based monocular SLAM-related methods: ORB-SLAM, REMODE, LSD-SLAM, and DPPTAM, and analyzes their feasibility for a mobile robot application in indoor environment. We tested these methods using video data that was recorded from a conventional wide-angle full HD webcam with a rolling shutter. The camera was mounted on a human-operated prototype of an unmanned ground vehicle, which followed a closed-loop trajectory. Both feature-based methods (ORB-SLAM, REMODE) and direct SLAMrelated algorithms (LSD-SLAM, DPPTAM) demonstrated reasonably good results in detection of volumetric objects, corners, obstacles and other local features. However, we met difficulties with recovering typical for offices homogeneously colored walls, since all of these methods created empty spaces in a reconstructed sparse 3D scene. This may cause collisions of an autonomously guided robot with unfeatured walls and thus limits applicability of maps, which are obtained by the considered monocular SLAM-related methods for indoor robot navigation.

Environment exploration and SLAM experiment research based on ROS

NASA Astrophysics Data System (ADS)

Li, Zhize; Zheng, Wei

2017-11-01

Robots need to get the information of surrounding environment by means of map learning. SLAM or navigation based on mobile robots is developing rapidly. ROS (Robot Operating System) is widely used in the field of robots because of the convenient code reuse and open source. Numerous excellent algorithms of SLAM or navigation are ported to ROS package. hector_slam is one of them that can set up occupancy grid maps on-line fast with low computation resources requiring. Its characters above make the embedded handheld mapping system possible. Similarly, hector_navigation also does well in the navigation field. It can finish path planning and environment exploration by itself using only an environmental sensor. Combining hector_navigation with hector_slam can realize low cost environment exploration, path planning and slam at the same time

Probability Analysis of the Wave-Slamming Pressure Values of the Horizontal Deck with Elastic Support

NASA Astrophysics Data System (ADS)

Zuo, Weiguang; Liu, Ming; Fan, Tianhui; Wang, Pengtao

2018-06-01

This paper presents the probability distribution of the slamming pressure from an experimental study of regular wave slamming on an elastically supported horizontal deck. The time series of the slamming pressure during the wave impact were first obtained through statistical analyses on experimental data. The exceeding probability distribution of the maximum slamming pressure peak and distribution parameters were analyzed, and the results show that the exceeding probability distribution of the maximum slamming pressure peak accords with the three-parameter Weibull distribution. Furthermore, the range and relationships of the distribution parameters were studied. The sum of the location parameter D and the scale parameter L was approximately equal to 1.0, and the exceeding probability was more than 36.79% when the random peak was equal to the sample average during the wave impact. The variation of the distribution parameters and slamming pressure under different model conditions were comprehensively presented, and the parameter values of the Weibull distribution of wave-slamming pressure peaks were different due to different test models. The parameter values were found to decrease due to the increased stiffness of the elastic support. The damage criterion of the structure model caused by the wave impact was initially discussed, and the structure model was destroyed when the average slamming time was greater than a certain value during the duration of the wave impact. The conclusions of the experimental study were then described.

Towards Unmanned Systems for Dismounted Operations in the Canadian Forces

DTIC Science & Technology

2011-01-01

LIDAR , and RADAR) and lower power/mass, passive imaging techniques such as structure from motion and simultaneous localisation and mapping ( SLAM ...sensors and learning algorithms. 5.1.2 Simultaneous localisation and mapping SLAM algorithms concurrently estimate a robot pose and a map of unique...locations and vehicle pose are part of the SLAM state vector and are estimated in each update step. AISS developed a monocular camera-based SLAM

Performance analysis of the Microsoft Kinect sensor for 2D Simultaneous Localization and Mapping (SLAM) techniques.

PubMed

Kamarudin, Kamarulzaman; Mamduh, Syed Muhammad; Shakaff, Ali Yeon Md; Zakaria, Ammar

2014-12-05

This paper presents a performance analysis of two open-source, laser scanner-based Simultaneous Localization and Mapping (SLAM) techniques (i.e., Gmapping and Hector SLAM) using a Microsoft Kinect to replace the laser sensor. Furthermore, the paper proposes a new system integration approach whereby a Linux virtual machine is used to run the open source SLAM algorithms. The experiments were conducted in two different environments; a small room with no features and a typical office corridor with desks and chairs. Using the data logged from real-time experiments, each SLAM technique was simulated and tested with different parameter settings. The results show that the system is able to achieve real time SLAM operation. The system implementation offers a simple and reliable way to compare the performance of Windows-based SLAM algorithm with the algorithms typically implemented in a Robot Operating System (ROS). The results also indicate that certain modifications to the default laser scanner-based parameters are able to improve the map accuracy. However, the limited field of view and range of Kinect's depth sensor often causes the map to be inaccurate, especially in featureless areas, therefore the Kinect sensor is not a direct replacement for a laser scanner, but rather offers a feasible alternative for 2D SLAM tasks.

Performance Analysis of the Microsoft Kinect Sensor for 2D Simultaneous Localization and Mapping (SLAM) Techniques

PubMed Central

Kamarudin, Kamarulzaman; Mamduh, Syed Muhammad; Shakaff, Ali Yeon Md; Zakaria, Ammar

2014-01-01

This paper presents a performance analysis of two open-source, laser scanner-based Simultaneous Localization and Mapping (SLAM) techniques (i.e., Gmapping and Hector SLAM) using a Microsoft Kinect to replace the laser sensor. Furthermore, the paper proposes a new system integration approach whereby a Linux virtual machine is used to run the open source SLAM algorithms. The experiments were conducted in two different environments; a small room with no features and a typical office corridor with desks and chairs. Using the data logged from real-time experiments, each SLAM technique was simulated and tested with different parameter settings. The results show that the system is able to achieve real time SLAM operation. The system implementation offers a simple and reliable way to compare the performance of Windows-based SLAM algorithm with the algorithms typically implemented in a Robot Operating System (ROS). The results also indicate that certain modifications to the default laser scanner-based parameters are able to improve the map accuracy. However, the limited field of view and range of Kinect's depth sensor often causes the map to be inaccurate, especially in featureless areas, therefore the Kinect sensor is not a direct replacement for a laser scanner, but rather offers a feasible alternative for 2D SLAM tasks. PMID:25490595

An Adaptive Scheme for Robot Localization and Mapping with Dynamically Configurable Inter-Beacon Range Measurements

PubMed Central

Torres-González, Arturo; Martinez-de Dios, Jose Ramiro; Ollero, Anibal

2014-01-01

This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons) are used as landmarks for range-only (RO) simultaneous localization and mapping (SLAM). This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM) and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively) than traditional methods with a lower computational burden (16%) and similar beacon energy consumption. PMID:24776938

An adaptive scheme for robot localization and mapping with dynamically configurable inter-beacon range measurements.

PubMed

Torres-González, Arturo; Martinez-de Dios, Jose Ramiro; Ollero, Anibal

2014-04-25

This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons) are used as landmarks for range-only (RO) simultaneous localization and mapping (SLAM). This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM) and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively) than traditional methods with a lower computational burden (16%) and similar beacon energy consumption.

A robust approach for a filter-based monocular simultaneous localization and mapping (SLAM) system.

PubMed

Munguía, Rodrigo; Castillo-Toledo, Bernardino; Grau, Antoni

2013-07-03

Simultaneous localization and mapping (SLAM) is an important problem to solve in robotics theory in order to build truly autonomous mobile robots. This work presents a novel method for implementing a SLAM system based on a single camera sensor. The SLAM with a single camera, or monocular SLAM, is probably one of the most complex SLAM variants. In this case, a single camera, which is freely moving through its environment, represents the sole sensor input to the system. The sensors have a large impact on the algorithm used for SLAM. Cameras are used more frequently, because they provide a lot of information and are well adapted for embedded systems: they are light, cheap and power-saving. Nevertheless, and unlike range sensors, which provide range and angular information, a camera is a projective sensor providing only angular measurements of image features. Therefore, depth information (range) cannot be obtained in a single step. In this case, special techniques for feature system-initialization are needed in order to enable the use of angular sensors (as cameras) in SLAM systems. The main contribution of this work is to present a novel and robust scheme for incorporating and measuring visual features in filtering-based monocular SLAM systems. The proposed method is based in a two-step technique, which is intended to exploit all the information available in angular measurements. Unlike previous schemes, the values of parameters used by the initialization technique are derived directly from the sensor characteristics, thus simplifying the tuning of the system. The experimental results show that the proposed method surpasses the performance of previous schemes.

Epithelial-mesenchymal transition abolishes the susceptibility of polarized epithelial cell lines to measles virus.

PubMed

Shirogane, Yuta; Takeda, Makoto; Tahara, Maino; Ikegame, Satoshi; Nakamura, Takanori; Yanagi, Yusuke

2010-07-02

Measles virus (MV), an enveloped negative-strand RNA virus, remains a major cause of morbidity and mortality in developing countries. MV predominantly infects immune cells by using signaling lymphocyte activation molecule (SLAM; also called CD150) as a receptor, but it also infects polarized epithelial cells, forming tight junctions in a SLAM-independent manner. Although the ability of MV to infect polarized epithelial cells is thought to be important for its transmission, the epithelial cell receptor for MV has not been identified. A transcriptional repressor, Snail, induces epithelial-mesenchymal transition (EMT), in which epithelial cells lose epithelial cell phenotypes, such as adherens and tight junctions. In this study, EMT was induced by expressing Snail in a lung adenocarcinoma cell line, II-18, which is highly susceptible to wild-type MV. Snail-expressing II-18 cells lost adherens and tight junctions. Microarray analysis confirmed the induction of EMT in II-18 cells and suggested a novel function of Snail in protein degradation and distribution. Importantly, wild-type MV no longer entered EMT-induced II-18 cells, suggesting that the epithelial cell receptor is down-regulated by the induction of EMT. Other polarized cell lines, NCI-H358 and HT-29, also lost susceptibility to wild-type MV when EMT was induced. However, the complete formation of tight junctions rather reduced MV entry into HT-29 cells. Taken together, these data suggest that the unidentified epithelial cell receptor for MV is involved in the formation of epithelial intercellular junctions.

H-SLAM: Rao-Blackwellized Particle Filter SLAM Using Hilbert Maps.

PubMed

Vallicrosa, Guillem; Ridao, Pere

2018-05-01

Occupancy Grid maps provide a probabilistic representation of space which is important for a variety of robotic applications like path planning and autonomous manipulation. In this paper, a SLAM (Simultaneous Localization and Mapping) framework capable of obtaining this representation online is presented. The H-SLAM (Hilbert Maps SLAM) is based on Hilbert Map representation and uses a Particle Filter to represent the robot state. Hilbert Maps offer a continuous probabilistic representation with a small memory footprint. We present a series of experimental results carried both in simulation and with real AUVs (Autonomous Underwater Vehicles). These results demonstrate that our approach is able to represent the environment more consistently while capable of running online.

Systemic lupus erythematosus in three ethnic groups. XIV. Poverty, wealth, and their influence on disease activity.

PubMed

Alarcón, Graciela S; McGwin, Gerald; Sanchez, Martha L; Bastian, Holly M; Fessler, Barri J; Friedman, Alan W; Baethge, Bruce A; Roseman, Jeffrey; Reveille, John D

2004-02-15

To determine the impact of wealth on disease activity in the multiethnic (Hispanic, African American, and Caucasian) LUMINA (Lupus in Minorities, Nature versus nurture) cohort of patients with systemic lupus erythematosus (SLE) and disease duration < or =5 years at enrollment. Variables (socioeconomic, demographic, clinical, immunologic, immunogenetic, behavioral, and psychological) were measured at enrollment and annually thereafter. Four questions from the Women's Health Initiative study were used to measure wealth. Disease activity was measured with the Systemic Lupus Activity Measure (SLAM). The relationship between the different variables and wealth was then examined. Next, the impact of wealth on disease activity was examined in regression models where the dependent variables were the SLAM score and SLAM global (physician). Variables previously found to impact disease activity plus the wealth questions were included in the models. Questions on income, assets, and debt were found to distinguish patients into groups, wealthier and less wealthy. Less wealthy patients tended to be younger, women, noncaucasian, less educated, unmarried, less likely to have health insurance, and more likely to live below the poverty line. They also tended to have more active disease, more abnormal illness-related behaviors, less social support, and lower levels of self reported mental functioning. None of the wealth questions was retained in the regression models, although other socioeconomic features (such as African American ethnicity, poverty, and younger age) did. Wealth, per se, does not appear to have an additional predictive value, over and above traditional measures of socioeconomic status, in SLE disease activity.

A Robust Approach for a Filter-Based Monocular Simultaneous Localization and Mapping (SLAM) System

PubMed Central

Munguía, Rodrigo; Castillo-Toledo, Bernardino; Grau, Antoni

2013-01-01

Simultaneous localization and mapping (SLAM) is an important problem to solve in robotics theory in order to build truly autonomous mobile robots. This work presents a novel method for implementing a SLAM system based on a single camera sensor. The SLAM with a single camera, or monocular SLAM, is probably one of the most complex SLAM variants. In this case, a single camera, which is freely moving through its environment, represents the sole sensor input to the system. The sensors have a large impact on the algorithm used for SLAM. Cameras are used more frequently, because they provide a lot of information and are well adapted for embedded systems: they are light, cheap and power-saving. Nevertheless, and unlike range sensors, which provide range and angular information, a camera is a projective sensor providing only angular measurements of image features. Therefore, depth information (range) cannot be obtained in a single step. In this case, special techniques for feature system-initialization are needed in order to enable the use of angular sensors (as cameras) in SLAM systems. The main contribution of this work is to present a novel and robust scheme for incorporating and measuring visual features in filtering-based monocular SLAM systems. The proposed method is based in a two-step technique, which is intended to exploit all the information available in angular measurements. Unlike previous schemes, the values of parameters used by the initialization technique are derived directly from the sensor characteristics, thus simplifying the tuning of the system. The experimental results show that the proposed method surpasses the performance of previous schemes. PMID:23823972

Highly-accelerated quantitative 2D and 3D localized spectroscopy with linear algebraic modeling (SLAM) and sensitivity encoding

NASA Astrophysics Data System (ADS)

Zhang, Yi; Gabr, Refaat E.; Zhou, Jinyuan; Weiss, Robert G.; Bottomley, Paul A.

2013-12-01

Noninvasive magnetic resonance spectroscopy (MRS) with chemical shift imaging (CSI) provides valuable metabolic information for research and clinical studies, but is often limited by long scan times. Recently, spectroscopy with linear algebraic modeling (SLAM) was shown to provide compartment-averaged spectra resolved in one spatial dimension with many-fold reductions in scan-time. This was achieved using a small subset of the CSI phase-encoding steps from central image k-space that maximized the signal-to-noise ratio. Here, SLAM is extended to two- and three-dimensions (2D, 3D). In addition, SLAM is combined with sensitivity-encoded (SENSE) parallel imaging techniques, enabling the replacement of even more CSI phase-encoding steps to further accelerate scan-speed. A modified SLAM reconstruction algorithm is introduced that significantly reduces the effects of signal nonuniformity within compartments. Finally, main-field inhomogeneity corrections are provided, analogous to CSI. These methods are all tested on brain proton MRS data from a total of 24 patients with brain tumors, and in a human cardiac phosphorus 3D SLAM study at 3T. Acceleration factors of up to 120-fold versus CSI are demonstrated, including speed-up factors of 5-fold relative to already-accelerated SENSE CSI. Brain metabolites are quantified in SLAM and SENSE SLAM spectra and found to be indistinguishable from CSI measures from the same compartments. The modified reconstruction algorithm demonstrated immunity to maladjusted segmentation and errors from signal heterogeneity in brain data. In conclusion, SLAM demonstrates the potential to supplant CSI in studies requiring compartment-average spectra or large volume coverage, by dramatically reducing scan-time while providing essentially the same quantitative results.

An adaptive SVSF-SLAM algorithm to improve the success and solving the UGVs cooperation problem

NASA Astrophysics Data System (ADS)

Demim, Fethi; Nemra, Abdelkrim; Louadj, Kahina; Hamerlain, Mustapha; Bazoula, Abdelouahab

2018-05-01

This paper aims to present a Decentralised Cooperative Simultaneous Localization and Mapping (DCSLAM) solution based on 2D laser data using an Adaptive Covariance Intersection (ACI). The ACI-DCSLAM algorithm will be validated on a swarm of Unmanned Ground Vehicles (UGVs) receiving features to estimate the position and covariance of shared features before adding them to the global map. With the proposed solution, a group of (UGVs) will be able to construct a large reliable map and localise themselves within this map without any user intervention. The most popular solutions to this problem are the EKF-SLAM, Nonlinear H-infinity ? SLAM and the FAST-SLAM. The former suffers from two important problems which are the poor consistency caused by the linearization problem and the calculation of Jacobian. The second solution is the ? which is a very promising filter because it doesn't make any assumption about noise characteristics, while the latter is not suitable for real time implementation. Therefore, a new alternative solution based on the smooth variable structure filter (SVSF) is adopted. Cooperative adaptive SVSF-SLAM algorithm is proposed in this paper to solve the UGVs SLAM problem. Our main contribution consists in adapting the SVSF filter to solve the Decentralised Cooperative SLAM problem for multiple UGVs. The algorithms developed in this paper were implemented using two mobile robots Pioneer ?, equiped with 2D laser telemetry sensors. Good results are obtained by the Cooperative adaptive SVSF-SLAM algorithm compared to the Cooperative EKF/?-SLAM algorithms, especially when the noise is colored or affected by a variable bias. Simulation results confirm and show the efficiency of the proposed algorithm which is more robust, stable and adapted to real time applications.

Concurrent initialization for Bearing-Only SLAM.

PubMed

Munguía, Rodrigo; Grau, Antoni

2010-01-01

Simultaneous Localization and Mapping (SLAM) is perhaps the most fundamental problem to solve in robotics in order to build truly autonomous mobile robots. The sensors have a large impact on the algorithm used for SLAM. Early SLAM approaches focused on the use of range sensors as sonar rings or lasers. However, cameras have become more and more used, because they yield a lot of information and are well adapted for embedded systems: they are light, cheap and power saving. Unlike range sensors which provide range and angular information, a camera is a projective sensor which measures the bearing of images features. Therefore depth information (range) cannot be obtained in a single step. This fact has propitiated the emergence of a new family of SLAM algorithms: the Bearing-Only SLAM methods, which mainly rely in especial techniques for features system-initialization in order to enable the use of bearing sensors (as cameras) in SLAM systems. In this work a novel and robust method, called Concurrent Initialization, is presented which is inspired by having the complementary advantages of the Undelayed and Delayed methods that represent the most common approaches for addressing the problem. The key is to use concurrently two kinds of feature representations for both undelayed and delayed stages of the estimation. The simulations results show that the proposed method surpasses the performance of previous schemes.

The Adaptor Molecule Signaling Lymphocytic Activation Molecule (SLAM)-associated Protein (SAP) Is Essential in Mechanisms Involving the Fyn Tyrosine Kinase for Induction and Progression of Collagen-induced Arthritis

PubMed Central

Zhong, Ming-Chao; Veillette, André

2013-01-01

Signaling lymphocytic activation molecule-associated protein (SAP) is an Src homology 2 domain-only adaptor involved in multiple immune cell functions. It has also been linked to immunodeficiencies and autoimmune diseases, such as systemic lupus erythematosus. Here, we examined the role and mechanism of action of SAP in autoimmunity using a mouse model of autoimmune arthritis, collagen-induced arthritis (CIA). We found that SAP was essential for development of CIA in response to collagen immunization. It was also required for production of collagen-specific antibodies, which play a key role in disease pathogenesis. These effects required SAP expression in T cells, not in B cells. In mice immunized with a high dose of collagen, the activity of SAP was nearly independent of its ability to bind the protein tyrosine kinase Fyn and correlated with the capacity of SAP to promote full differentiation of follicular T helper (TFH) cells. However, with a lower dose of collagen, the role of SAP was more dependent on Fyn binding, suggesting that additional mechanisms other than TFH cell differentiation were involved. Further studies suggested that this might be due to a role of the SAP-Fyn interaction in natural killer T cell development through the ability of SAP-Fyn to promote Vav-1 activation. We also found that removal of SAP expression during progression of CIA attenuated disease severity. However, it had no effect on disease when CIA was clinically established. Together, these results indicate that SAP plays an essential role in CIA because of Fyn-independent and Fyn-dependent effects on TFH cells and, possibly, other T cell types. PMID:24045941

The adaptor molecule signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is essential in mechanisms involving the Fyn tyrosine kinase for induction and progression of collagen-induced arthritis.

PubMed

Zhong, Ming-Chao; Veillette, André

2013-11-01

Signaling lymphocytic activation molecule-associated protein (SAP) is an Src homology 2 domain-only adaptor involved in multiple immune cell functions. It has also been linked to immunodeficiencies and autoimmune diseases, such as systemic lupus erythematosus. Here, we examined the role and mechanism of action of SAP in autoimmunity using a mouse model of autoimmune arthritis, collagen-induced arthritis (CIA). We found that SAP was essential for development of CIA in response to collagen immunization. It was also required for production of collagen-specific antibodies, which play a key role in disease pathogenesis. These effects required SAP expression in T cells, not in B cells. In mice immunized with a high dose of collagen, the activity of SAP was nearly independent of its ability to bind the protein tyrosine kinase Fyn and correlated with the capacity of SAP to promote full differentiation of follicular T helper (TFH) cells. However, with a lower dose of collagen, the role of SAP was more dependent on Fyn binding, suggesting that additional mechanisms other than TFH cell differentiation were involved. Further studies suggested that this might be due to a role of the SAP-Fyn interaction in natural killer T cell development through the ability of SAP-Fyn to promote Vav-1 activation. We also found that removal of SAP expression during progression of CIA attenuated disease severity. However, it had no effect on disease when CIA was clinically established. Together, these results indicate that SAP plays an essential role in CIA because of Fyn-independent and Fyn-dependent effects on TFH cells and, possibly, other T cell types.

Outsiders' Art

ERIC Educational Resources Information Center

Gehring, John

2005-01-01

Slam poetry was born in the Green Mill Tavern, a one-time Chicago speakeasy where Al Capone imbibed, when a construction worker and poet named Marc Smith revolutionized poetry readings with an Uptown Poetry Slam in 1986. Slam borrows heavily from the rhythms and wordplay of rap and hip-hop, as well as the stream of consciousness and metaphysical…

Short Large-Amplitude Magnetic Structures (SLAMS) at Venus

NASA Technical Reports Server (NTRS)

Collinson, G. A.; Wilson, L. B.; Sibeck, D. G.; Shane, N.; Zhang, T. L.; Moore, T. E.; Coates, A. J.; Barabash, S.

2012-01-01

We present the first observation of magnetic fluctuations consistent with Short Large-Amplitude Magnetic Structures (SLAMS) in the foreshock of the planet Venus. Three monolithic magnetic field spikes were observed by the Venus Express on the 11th of April 2009. The structures were approx.1.5->11s in duration, had magnetic compression ratios between approx.3->6, and exhibited elliptical polarization. These characteristics are consistent with the SLAMS observed at Earth, Jupiter, and Comet Giacobini-Zinner, and thus we hypothesize that it is possible SLAMS may be found at any celestial body with a foreshock.

Concurrent Initialization for Bearing-Only SLAM

PubMed Central

Munguía, Rodrigo; Grau, Antoni

2010-01-01

Simultaneous Localization and Mapping (SLAM) is perhaps the most fundamental problem to solve in robotics in order to build truly autonomous mobile robots. The sensors have a large impact on the algorithm used for SLAM. Early SLAM approaches focused on the use of range sensors as sonar rings or lasers. However, cameras have become more and more used, because they yield a lot of information and are well adapted for embedded systems: they are light, cheap and power saving. Unlike range sensors which provide range and angular information, a camera is a projective sensor which measures the bearing of images features. Therefore depth information (range) cannot be obtained in a single step. This fact has propitiated the emergence of a new family of SLAM algorithms: the Bearing-Only SLAM methods, which mainly rely in especial techniques for features system-initialization in order to enable the use of bearing sensors (as cameras) in SLAM systems. In this work a novel and robust method, called Concurrent Initialization, is presented which is inspired by having the complementary advantages of the Undelayed and Delayed methods that represent the most common approaches for addressing the problem. The key is to use concurrently two kinds of feature representations for both undelayed and delayed stages of the estimation. The simulations results show that the proposed method surpasses the performance of previous schemes. PMID:22294884

A Multi-Sensorial Simultaneous Localization and Mapping (SLAM) System for Low-Cost Micro Aerial Vehicles in GPS-Denied Environments

PubMed Central

López, Elena; García, Sergio; Barea, Rafael; Bergasa, Luis M.; Molinos, Eduardo J.; Arroyo, Roberto; Romera, Eduardo; Pardo, Samuel

2017-01-01

One of the main challenges of aerial robots navigation in indoor or GPS-denied environments is position estimation using only the available onboard sensors. This paper presents a Simultaneous Localization and Mapping (SLAM) system that remotely calculates the pose and environment map of different low-cost commercial aerial platforms, whose onboard computing capacity is usually limited. The proposed system adapts to the sensory configuration of the aerial robot, by integrating different state-of-the art SLAM methods based on vision, laser and/or inertial measurements using an Extended Kalman Filter (EKF). To do this, a minimum onboard sensory configuration is supposed, consisting of a monocular camera, an Inertial Measurement Unit (IMU) and an altimeter. It allows to improve the results of well-known monocular visual SLAM methods (LSD-SLAM and ORB-SLAM are tested and compared in this work) by solving scale ambiguity and providing additional information to the EKF. When payload and computational capabilities permit, a 2D laser sensor can be easily incorporated to the SLAM system, obtaining a local 2.5D map and a footprint estimation of the robot position that improves the 6D pose estimation through the EKF. We present some experimental results with two different commercial platforms, and validate the system by applying it to their position control. PMID:28397758

Modeling, Simulation, and Characterization of Distributed Multi-Agent Systems

DTIC Science & Technology

2012-01-01

capabilities (vision, LIDAR , differential global positioning, ultrasonic proximity sensing, etc.), the agents comprising a MAS tend to have somewhat lesser...on the simultaneous localization and mapping ( SLAM ) problem [19]. SLAM acknowledges that externally-provided localization information is not...continually-updated mapping databases, generates a comprehensive representation of the spatial and spectral environment. Many times though, inherent SLAM

Canine distemper virus isolated from a monkey efficiently replicates on Vero cells expressing non-human primate SLAM receptors but not human SLAM receptor.

PubMed

Feng, Na; Liu, Yuxiu; Wang, Jianzhong; Xu, Weiwei; Li, Tiansong; Wang, Tiecheng; Wang, Lei; Yu, Yicong; Wang, Hualei; Zhao, Yongkun; Yang, Songtao; Gao, Yuwei; Hu, Guixue; Xia, Xianzhu

2016-08-02

In 2008, an outbreak of canine distemper virus (CDV) infection in monkeys was reported in China. We isolated CDV strain (subsequently named Monkey-BJ01-DV) from lung tissue obtained from a rhesus monkey that died in this outbreak. We evaluated the ability of this virus on Vero cells expressing SLAM receptors from dog, monkey and human origin, and analyzed the H gene of Monkey-BJ01-DV with other strains. The Monkey-BJ01-DV isolate replicated to the highest titer on Vero cells expressing dog-origin SLAM (10(5.2±0.2) TCID50/ml) and monkey-origin SLAM (10(5.4±0.1) TCID50/ml), but achieved markedly lower titers on human-origin SLAM cells (10(3.3±0.3) TCID50/ml). Phylogenetic analysis of the full-length H gene showed that Monkey-BJ01-DV was highly related to other CDV strains obtained during recent CDV epidemics among species of the Canidae family in China, and these Monkey strains CDV (Monkey-BJ01-DV, CYN07-dV, Monkey-KM-01) possessed a number of amino acid specific substitutions (E276V, Q392R, D435Y and I542F) compared to the H protein of CDV epidemic in other animals at the same period. Our results suggested that the monkey origin-CDV-H protein could possess specific substitutions to adapt to the new host. Monkey-BJ01-DV can efficiently use monkey- and dog-origin SLAM to infect and replicate in host cells, but further adaptation may be required for efficient replication in host cells expressing the human SLAM receptor.

a Variant of Lsd-Slam Capable of Processing High-Speed Low-Framerate Monocular Datasets

NASA Astrophysics Data System (ADS)

Schmid, S.; Fritsch, D.

2017-11-01

We develop a new variant of LSD-SLAM, called C-LSD-SLAM, which is capable of performing monocular tracking and mapping in high-speed low-framerate situations such as those of the KITTI datasets. The methods used here are robust against the influence of erronously triangulated points near the epipolar direction, which otherwise causes tracking divergence.

Shocklets, SLAMS, and Field-Aligned Ion Beams in the Terrestrial Foreshock

NASA Technical Reports Server (NTRS)

Wilson, L. B.; Koval, A.; Sibeck, D. G.; Szabo, A.; Cattell, C. A.; Kasper, J. C.; Maruca, B. A.; Pulupa, M.; Salem, C. S.; Wilber, M.

2012-01-01

We present Wind spacecraft observations of ion distributions showing field- aligned beams (FABs) and large-amplitude magnetic fluctuations composed of a series of shocklets and short large-amplitude magnetic structures (SLAMS). The FABs are found to have T(sub k) approx 80-850 eV, V(sub b)/V(sub sw) approx 1.3-2.4, T(sub perpendicular,b)/T(sub paralell,b) approx 1-8, and n(sub b)/n(sub o) approx 0.2-11%. Saturation amplitudes for ion/ion resonant and non-resonant instabilities are too small to explain the observed SLAMS amplitudes. We show two examples where groups of SLAMS can act like a local quasi-perpendicular shock reflecting ions to produce the FABs, a scenario distinct from the more-common production at the quasi-perpendicular bow shock. The SLAMS exhibit a foot-like magnetic enhancement with a leading magnetosonic whistler train, consistent with previous observations. Strong ion and electron heating are observed within the series of shocklets and SLAMS with temperatures increasing by factors approx > 5 and approx >3, respectively. Both the core and halo electron components show strong perpendicular heating inside the feature.

T Follicular Helper Cell-Germinal Center B Cell Interaction Strength Regulates Entry into Plasma Cell or Recycling Germinal Center Cell Fate.

PubMed

Ise, Wataru; Fujii, Kentaro; Shiroguchi, Katsuyuki; Ito, Ayako; Kometani, Kohei; Takeda, Kiyoshi; Kawakami, Eiryo; Yamashita, Kazuo; Suzuki, Kazuhiro; Okada, Takaharu; Kurosaki, Tomohiro

2018-04-17

Higher- or lower-affinity germinal center (GC) B cells are directed either to plasma cell or GC recycling, respectively; however, how commitment to the plasma cell fate takes place is unclear. We found that a population of light zone (LZ) GC cells, Bcl6 lo CD69 hi expressing a transcription factor IRF4 and higher-affinity B cell receptors (BCRs) or Bcl6 hi CD69 hi with lower-affinity BCRs, favored the plasma cell or recycling GC cell fate, respectively. Mechanistically, CD40 acted as a dose-dependent regulator for Bcl6 lo CD69 hi cell formation. Furthermore, we found that expression of intercellular adhesion molecule 1 (ICAM-1) and signaling lymphocytic activation molecule (SLAM) in Bcl6 lo CD69 hi cells was higher than in Bcl6 hi CD69 hi cells, thereby affording more stable T follicular helper (Tfh)-GC B cell contacts. These data support a model whereby commitment to the plasma cell begins in the GC and suggest that stability of Tfh-GC B cell contacts is key for plasma cell-prone GC cell formation. Copyright © 2018. Published by Elsevier Inc.

Kernelized Locality-Sensitive Hashing for Fast Image Landmark Association

DTIC Science & Technology

2011-03-24

based Simultaneous Localization and Mapping ( SLAM ). The problem, however, is that vision-based navigation techniques can re- quire excessive amounts of...up and optimizing the data association process in vision-based SLAM . Specifically, this work studies the current methods that algorithms use to...required for location identification than that of other methods. This work can then be extended into a vision- SLAM implementation to subsequently

The South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLAM BRC) case register: development and descriptive data.

PubMed

Stewart, Robert; Soremekun, Mishael; Perera, Gayan; Broadbent, Matthew; Callard, Felicity; Denis, Mike; Hotopf, Matthew; Thornicroft, Graham; Lovestone, Simon

2009-08-12

Case registers have been used extensively in mental health research. Recent developments in electronic medical records, and in computer software to search and analyse these in anonymised format, have the potential to revolutionise this research tool. We describe the development of the South London and Maudsley NHS Foundation Trust (SLAM) Biomedical Research Centre (BRC) Case Register Interactive Search tool (CRIS) which allows research-accessible datasets to be derived from SLAM, the largest provider of secondary mental healthcare in Europe. All clinical data, including free text, are available for analysis in the form of anonymised datasets. Development involved both the building of the system and setting in place the necessary security (with both functional and procedural elements). Descriptive data are presented for the Register database as of October 2008. The database at that point included 122,440 cases, 35,396 of whom were receiving active case management under the Care Programme Approach. In terms of gender and ethnicity, the database was reasonably representative of the source population. The most common assigned primary diagnoses were within the ICD mood disorders (n = 12,756) category followed by schizophrenia and related disorders (8158), substance misuse (7749), neuroses (7105) and organic disorders (6414). The SLAM BRC Case Register represents a 'new generation' of this research design, built on a long-running system of fully electronic clinical records and allowing in-depth secondary analysis of both numerical, string and free text data, whilst preserving anonymity through technical and procedural safeguards.

Research of cartographer laser SLAM algorithm

NASA Astrophysics Data System (ADS)

Xu, Bo; Liu, Zhengjun; Fu, Yiran; Zhang, Changsai

2017-11-01

As the indoor is a relatively closed and small space, total station, GPS, close-range photogrammetry technology is difficult to achieve fast and accurate indoor three-dimensional space reconstruction task. LIDAR SLAM technology does not rely on the external environment a priori knowledge, only use their own portable lidar, IMU, odometer and other sensors to establish an independent environment map, a good solution to this problem. This paper analyzes the Google Cartographer laser SLAM algorithm from the point cloud matching and closed loop detection. Finally, the algorithm is presented in the 3D visualization tool RViz from the data acquisition and processing to create the environment map, complete the SLAM technology and realize the process of indoor threedimensional space reconstruction

Ultra wide-band localization and SLAM: a comparative study for mobile robot navigation.

PubMed

Segura, Marcelo J; Auat Cheein, Fernando A; Toibero, Juan M; Mut, Vicente; Carelli, Ricardo

2011-01-01

In this work, a comparative study between an Ultra Wide-Band (UWB) localization system and a Simultaneous Localization and Mapping (SLAM) algorithm is presented. Due to its high bandwidth and short pulses length, UWB potentially allows great accuracy in range measurements based on Time of Arrival (TOA) estimation. SLAM algorithms recursively estimates the map of an environment and the pose (position and orientation) of a mobile robot within that environment. The comparative study presented here involves the performance analysis of implementing in parallel an UWB localization based system and a SLAM algorithm on a mobile robot navigating within an environment. Real time results as well as error analysis are also shown in this work.

Map generation in unknown environments by AUKF-SLAM using line segment-type and point-type landmarks

NASA Astrophysics Data System (ADS)

Nishihta, Sho; Maeyama, Shoichi; Watanebe, Keigo

2018-02-01

Recently, autonomous mobile robots that collect information at disaster sites are being developed. Since it is difficult to obtain maps in advance in disaster sites, the robots being capable of autonomous movement under unknown environments are required. For this objective, the robots have to build maps, as well as the estimation of self-location. This is called a SLAM problem. In particular, AUKF-SLAM which uses corners in the environment as point-type landmarks has been developed as a solution method so far. However, when the robots move in an environment like a corridor consisting of few point-type features, the accuracy of self-location estimated by the landmark is decreased and it causes some distortions in the map. In this research, we propose AUKF-SLAM which uses walls in the environment as a line segment-type landmark. We demonstrate that the robot can generate maps in unknown environment by AUKF-SLAM, using line segment-type and point-type landmarks.

Multi-Autonomous Ground-robotic International Challenge (MAGIC) 2010

DTIC Science & Technology

2010-12-14

SLAM technique since this setup, having a LIDAR with long-range high-accuracy measurement capability, allows accurate localization and mapping more...achieve the accuracy of 25cm due to the use of multi-dimensional information. OGM is, similarly to SLAM , carried out by using LIDAR data. The OGM...a result of the development and implementation of the hybrid feature-based/scan-matching Simultaneous Localization and Mapping ( SLAM ) technique, the

Antagonistic Pleiotropy and Fitness Trade-Offs Reveal Specialist and Generalist Traits in Strains of Canine Distemper Virus

PubMed Central

Nikolin, Veljko M.; Osterrieder, Klaus; von Messling, Veronika; Hofer, Heribert; Anderson, Danielle; Dubovi, Edward; Brunner, Edgar; East, Marion L.

2012-01-01

Theoretically, homogeneous environments favor the evolution of specialists whereas heterogeneous environments favor generalists. Canine distemper is a multi-host carnivore disease caused by canine distemper virus (CDV). The described cell receptor of CDV is SLAM (CD150). Attachment of CDV hemagglutinin protein (CDV-H) to this receptor facilitates fusion and virus entry in cooperation with the fusion protein (CDV-F). We investigated whether CDV strains co-evolved in the large, homogeneous domestic dog population exhibited specialist traits, and strains adapted to the heterogeneous environment of smaller populations of different carnivores exhibited generalist traits. Comparison of amino acid sequences of the SLAM binding region revealed higher similarity between sequences from Canidae species than to sequences from other carnivore families. Using an in vitro assay, we quantified syncytia formation mediated by CDV-H proteins from dog and non-dog CDV strains in cells expressing dog, lion or cat SLAM. CDV-H proteins from dog strains produced significantly higher values with cells expressing dog SLAM than with cells expressing lion or cat SLAM. CDV-H proteins from strains of non-dog species produced similar values in all three cell types, but lower values in cells expressing dog SLAM than the values obtained for CDV-H proteins from dog strains. By experimentally changing one amino acid (Y549H) in the CDV-H protein of one dog strain we decreased expression of specialist traits and increased expression of generalist traits, thereby confirming its functional importance. A virus titer assay demonstrated that dog strains produced higher titers in cells expressing dog SLAM than cells expressing SLAM of non-dog hosts, which suggested possible fitness benefits of specialization post-cell entry. We provide in vitro evidence for the expression of specialist and generalist traits by CDV strains, and fitness trade-offs across carnivore host environments caused by antagonistic pleiotropy. These findings extend knowledge on CDV molecular epidemiology of particular relevance to wild carnivores. PMID:23239996

Slowing ash mortality: a potential strategy to slam emerald ash borer in outlier sites

Treesearch

Deborah G. McCullough; Nathan W. Siegert; John Bedford

2009-01-01

Several isolated outlier populations of emerald ash borer (Agrilus planipennis Fairmaire) were discovered in 2008 and additional outliers will likely be found as detection surveys and public outreach activities...

M3RSM: Many-to-Many Multi-Resolution Scan Matching

DTIC Science & Technology

2015-05-01

a localization problem), or may be derived from a LIDAR scan earlier in the robot’s trajectory (a SLAM problem). The reference map is generally...Mapping ( SLAM ) systems prevent the unbounded accumulation of error. A typical approach with laser range-finder data is to compute the posterior...even greater bottleneck than the SLAM optimiza- tion itself. In our multi-robot mapping system, over a dozen robots explored an area simultaneously [14

Development and Demonstration of Autonomous Behaviors for Urban Environment Exploration

DTIC Science & Technology

2012-04-01

exploration, mapping, localization, autonomy, lidar , SLAM 1. INTRODUCTION As global conflicts move into more urban settings, unmanned ground vehicles...mounted Hokuyo lidar is paired with a vertically mounted Hokuyo lidar as an inexpensive way for 3D perception of the environment. In addition, a pair...and mapping ( SLAM ) problem do exist,2–4 most have yet to tackle the problem of online SLAM throughout a multi-story building and/or incorporating

NDE of structural ceramics

NASA Technical Reports Server (NTRS)

Klima, S. J.; Vary, A.

1986-01-01

Radiographic, ultrasonic, scanning laser acoustic microscopy (SLAM), and thermo-acoustic microscopy techniques were used to characterize silicon nitride and silicon carbide modulus-of-rupture test specimens in various stages of fabrication. Conventional and microfocus X-ray techniques were found capable of detecting minute high density inclusions in as-received powders, green compacts, and fully densified specimens. Significant density gradients in sintered bars were observed by radiography, ultrasonic velocity, and SLAM. Ultrasonic attenuation was found sensitive to microstructural variations due to grain and void morphology and distribution. SLAM was also capable of detecting voids, inclusions and cracks in finished test bars. Consideration is given to the potential for applying thermo-acoustic microscopy techniques to green and densified ceramics. The detection probability statistics and some limitations of radiography and SLAM also are discussed.

Ultra Wide-Band Localization and SLAM: A Comparative Study for Mobile Robot Navigation

PubMed Central

Segura, Marcelo J.; Auat Cheein, Fernando A.; Toibero, Juan M.; Mut, Vicente; Carelli, Ricardo

2011-01-01

In this work, a comparative study between an Ultra Wide-Band (UWB) localization system and a Simultaneous Localization and Mapping (SLAM) algorithm is presented. Due to its high bandwidth and short pulses length, UWB potentially allows great accuracy in range measurements based on Time of Arrival (TOA) estimation. SLAM algorithms recursively estimates the map of an environment and the pose (position and orientation) of a mobile robot within that environment. The comparative study presented here involves the performance analysis of implementing in parallel an UWB localization based system and a SLAM algorithm on a mobile robot navigating within an environment. Real time results as well as error analysis are also shown in this work. PMID:22319397

Mutant Fusion Proteins with Enhanced Fusion Activity Promote Measles Virus Spread in Human Neuronal Cells and Brains of Suckling Hamsters

PubMed Central

Shirogane, Yuta; Suzuki, Satoshi O.; Ikegame, Satoshi; Koga, Ritsuko

2013-01-01

Subacute sclerosing panencephalitis (SSPE) is a fatal degenerative disease caused by persistent measles virus (MV) infection in the central nervous system (CNS). From the genetic study of MV isolates obtained from SSPE patients, it is thought that defects of the matrix (M) protein play a crucial role in MV pathogenicity in the CNS. In this study, we report several notable mutations in the extracellular domain of the MV fusion (F) protein, including those found in multiple SSPE strains. The F proteins with these mutations induced syncytium formation in cells lacking SLAM and nectin 4 (receptors used by wild-type MV), including human neuronal cell lines, when expressed together with the attachment protein hemagglutinin. Moreover, recombinant viruses with these mutations exhibited neurovirulence in suckling hamsters, unlike the parental wild-type MV, and the mortality correlated with their fusion activity. In contrast, the recombinant MV lacking the M protein did not induce syncytia in cells lacking SLAM and nectin 4, although it formed larger syncytia in cells with either of the receptors. Since human neuronal cells are mainly SLAM and nectin 4 negative, fusion-enhancing mutations in the extracellular domain of the F protein may greatly contribute to MV spread via cell-to-cell fusion in the CNS, regardless of defects of the M protein. PMID:23255801

Identification of amino acid substitutions with compensational effects in the attachment protein of canine distemper virus.

PubMed

Sattler, Ursula; Khosravi, Mojtaba; Avila, Mislay; Pilo, Paola; Langedijk, Johannes P; Ader-Ebert, Nadine; Alves, Lisa A; Plattet, Philippe; Origgi, Francesco C

2014-07-01

The hemagglutinin (H) gene of canine distemper virus (CDV) encodes the receptor-binding protein. This protein, together with the fusion (F) protein, is pivotal for infectivity since it contributes to the fusion of the viral envelope with the host cell membrane. Of the two receptors currently known for CDV (nectin-4 and the signaling lymphocyte activation molecule [SLAM]), SLAM is considered the most relevant for host susceptibility. To investigate how evolution might have impacted the host-CDV interaction, we examined the functional properties of a series of missense single nucleotide polymorphisms (SNPs) naturally accumulating within the H-gene sequences during the transition between two distinct but related strains. The two strains, a wild-type strain and a consensus strain, were part of a single continental outbreak in European wildlife and occurred in distinct geographical areas 2 years apart. The deduced amino acid sequence of the two H genes differed at 5 residues. A panel of mutants carrying all the combinations of the SNPs was obtained by site-directed mutagenesis. The selected mutant, wild type, and consensus H proteins were functionally evaluated according to their surface expression, SLAM binding, fusion protein interaction, and cell fusion efficiencies. The results highlight that the most detrimental functional effects are associated with specific sets of SNPs. Strikingly, an efficient compensational system driven by additional SNPs appears to come into play, virtually neutralizing the negative functional effects. This system seems to contribute to the maintenance of the tightly regulated function of the H-gene-encoded attachment protein. Importance: To investigate how evolution might have impacted the host-canine distemper virus (CDV) interaction, we examined the functional properties of naturally occurring single nucleotide polymorphisms (SNPs) in the hemagglutinin gene of two related but distinct strains of CDV. The hemagglutinin gene encodes the attachment protein, which is pivotal for infection. Our results show that few SNPs have a relevant detrimental impact and they generally appear in specific combinations (molecular signatures). These drastic negative changes are neutralized by compensatory mutations, which contribute to maintenance of an overall constant bioactivity of the attachment protein. This compensational mechanism might reflect the reaction of the CDV machinery to the changes occurring in the virus following antigenic variations critical for virulence. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Semantic data association for planar features in outdoor 6D-SLAM using lidar

NASA Astrophysics Data System (ADS)

Ulas, C.; Temeltas, H.

2013-05-01

Simultaneous Localization and Mapping (SLAM) is a fundamental problem of the autonomous systems in GPS (Global Navigation System) denied environments. The traditional probabilistic SLAM methods uses point features as landmarks and hold all the feature positions in their state vector in addition to the robot pose. The bottleneck of the point-feature based SLAM methods is the data association problem, which are mostly based on a statistical measure. The data association performance is very critical for a robust SLAM method since all the filtering strategies are applied after a known correspondence. For point-features, two different but very close landmarks in the same scene might be confused while giving the correspondence decision when their positions and error covariance matrix are solely taking into account. Instead of using the point features, planar features can be considered as an alternative landmark model in the SLAM problem to be able to provide a more consistent data association. Planes contain rich information for the solution of the data association problem and can be distinguished easily with respect to point features. In addition, planar maps are very compact since an environment has only very limited number of planar structures. The planar features does not have to be large structures like building wall or roofs; the small plane segments can also be used as landmarks like billboards, traffic posts and some part of the bridges in urban areas. In this paper, a probabilistic plane-feature extraction method from 3DLiDAR data and the data association based on the extracted semantic information of the planar features is introduced. The experimental results show that the semantic data association provides very satisfactory result in outdoor 6D-SLAM.

Advances in Simultaneous Localization and Mapping in Confined Underwater Environments Using Sonar and Optical Imaging

DTIC Science & Technology

2016-01-01

satisfying journeys in my life. I would like to thank Ryan for his guidance through the truly exciting world of mobile robotics and robotic perception. Thank...Multi-session and Multi-robot SLAM . . . . . . . . . . . . . . . 15 1.3.3 Robust Techniques for SLAM Backends . . . . . . . . . . . . . . 18 1.4 A...sonar. xv CHAPTER 1 Introduction 1.1 The Importance of SLAM in Autonomous Robotics Autonomous mobile robots are becoming a promising aid in a wide

Accurate Mobile Urban Mapping via Digital Map-Based SLAM †

PubMed Central

Roh, Hyunchul; Jeong, Jinyong; Cho, Younggun; Kim, Ayoung

2016-01-01

This paper presents accurate urban map generation using digital map-based Simultaneous Localization and Mapping (SLAM). Throughout this work, our main objective is generating a 3D and lane map aiming for sub-meter accuracy. In conventional mapping approaches, achieving extremely high accuracy was performed by either (i) exploiting costly airborne sensors or (ii) surveying with a static mapping system in a stationary platform. Mobile scanning systems recently have gathered popularity but are mostly limited by the availability of the Global Positioning System (GPS). We focus on the fact that the availability of GPS and urban structures are both sporadic but complementary. By modeling both GPS and digital map data as measurements and integrating them with other sensor measurements, we leverage SLAM for an accurate mobile mapping system. Our proposed algorithm generates an efficient graph SLAM and achieves a framework running in real-time and targeting sub-meter accuracy with a mobile platform. Integrated with the SLAM framework, we implement a motion-adaptive model for the Inverse Perspective Mapping (IPM). Using motion estimation derived from SLAM, the experimental results show that the proposed approaches provide stable bird’s-eye view images, even with significant motion during the drive. Our real-time map generation framework is validated via a long-distance urban test and evaluated at randomly sampled points using Real-Time Kinematic (RTK)-GPS. PMID:27548175

RGB-D SLAM Combining Visual Odometry and Extended Information Filter

PubMed Central

Zhang, Heng; Liu, Yanli; Tan, Jindong; Xiong, Naixue

2015-01-01

In this paper, we present a novel RGB-D SLAM system based on visual odometry and an extended information filter, which does not require any other sensors or odometry. In contrast to the graph optimization approaches, this is more suitable for online applications. A visual dead reckoning algorithm based on visual residuals is devised, which is used to estimate motion control input. In addition, we use a novel descriptor called binary robust appearance and normals descriptor (BRAND) to extract features from the RGB-D frame and use them as landmarks. Furthermore, considering both the 3D positions and the BRAND descriptors of the landmarks, our observation model avoids explicit data association between the observations and the map by marginalizing the observation likelihood over all possible associations. Experimental validation is provided, which compares the proposed RGB-D SLAM algorithm with just RGB-D visual odometry and a graph-based RGB-D SLAM algorithm using the publicly-available RGB-D dataset. The results of the experiments demonstrate that our system is quicker than the graph-based RGB-D SLAM algorithm. PMID:26263990

The South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLAM BRC) case register: development and descriptive data

PubMed Central

Stewart, Robert; Soremekun, Mishael; Perera, Gayan; Broadbent, Matthew; Callard, Felicity; Denis, Mike; Hotopf, Matthew; Thornicroft, Graham; Lovestone, Simon

2009-01-01

Background Case registers have been used extensively in mental health research. Recent developments in electronic medical records, and in computer software to search and analyse these in anonymised format, have the potential to revolutionise this research tool. Methods We describe the development of the South London and Maudsley NHS Foundation Trust (SLAM) Biomedical Research Centre (BRC) Case Register Interactive Search tool (CRIS) which allows research-accessible datasets to be derived from SLAM, the largest provider of secondary mental healthcare in Europe. All clinical data, including free text, are available for analysis in the form of anonymised datasets. Development involved both the building of the system and setting in place the necessary security (with both functional and procedural elements). Results Descriptive data are presented for the Register database as of October 2008. The database at that point included 122,440 cases, 35,396 of whom were receiving active case management under the Care Programme Approach. In terms of gender and ethnicity, the database was reasonably representative of the source population. The most common assigned primary diagnoses were within the ICD mood disorders (n = 12,756) category followed by schizophrenia and related disorders (8158), substance misuse (7749), neuroses (7105) and organic disorders (6414). Conclusion The SLAM BRC Case Register represents a 'new generation' of this research design, built on a long-running system of fully electronic clinical records and allowing in-depth secondary analysis of both numerical, string and free text data, whilst preserving anonymity through technical and procedural safeguards. PMID:19674459

The Adaptor Protein SAP Directly Associates with CD3ζ Chain and Regulates T Cell Receptor Signaling

PubMed Central

Proust, Richard; Bertoglio, Jacques; Gesbert, Franck

2012-01-01

Mutations altering the gene encoding the SLAM associated protein (SAP) are responsible for the X-linked lymphoproliferative disease or XLP1. Its absence is correlated with a defective NKT cells development, a decrease in B cell functions and a reduced T cells and NK cells cytotoxic activities, thus leading to an immunodeficiency syndrome. SAP is a small 128 amino-acid long protein that is almost exclusively composed of an SH2 domain. It has been shown to interact with the CD150/SLAM family of receptors, and in a non-canonical manner with SH3 containing proteins such as Fyn, βPIX, PKCθ and Nck1. It would thus play the role of a minimal adaptor protein. It has been shown that SAP plays an important function in the activation of T cells through its interaction with the SLAM family of receptors. Therefore SAP defective T cells display a reduced activation of signaling events downstream of the TCR-CD3 complex triggering. In the present work, we evidence that SAP is a direct interactor of the CD3ζ chain. This direct interaction occurs through the first ITAM of CD3ζ, proximal to the membrane. Additionally, we show that, in the context of the TCR-CD3 signaling, an Sh-RNA mediated silencing of SAP is responsible for a decrease of several canonical T cell signaling pathways including Erk, Akt and PLCγ1 and to a reduced induction of IL-2 and IL-4 mRNA. Altogether, we show that SAP plays a central function in the T cell activation processes through a direct association with the CD3 complex. PMID:22912825

Matching of Ground-Based LiDAR and Aerial Image Data For Mobile Robot Localization in Densely Forested Environments

DTIC Science & Technology

2013-11-01

for rovers operating in close proximity to points of interest. Techniques such as Simultaneous Localization and Mapping ( SLAM ) have been utilized...successfully to localize rovers in a variety of settings and scenarios [3,4]. SLAM focuses on building a local map of landmarks as observed by a rover...more landmarks are observed and errors filtered. SLAM therefore does not require a priori knowledge of the locations of landmarks or that of the rover

Fatal canine distemper virus infection of giant pandas in China

PubMed Central

Feng, Na; Yu, Yicong; Wang, Tiecheng; Wilker, Peter; Wang, Jianzhong; Li, Yuanguo; Sun, Zhe; Gao, Yuwei; Xia, Xianzhu

2016-01-01

We report an outbreak of canine distemper virus (CDV) infection among endangered giant pandas (Ailuropoda melanoleuca). Five of six CDV infected giant pandas died. The surviving giant panda was previously vaccinated against CDV. Genomic sequencing of CDV isolated from one of the infected pandas (giant panda/SX/2014) suggests it belongs to the Asia-1 cluster. The hemagglutinin protein of the isolated virus and virus sequenced from lung samples originating from deceased giant pandas all possessed the substitutions V26M, T213A, K281R, S300N, P340Q, and Y549H. The presence of the Y549H substitution is notable as it is found at the signaling lymphocytic activation molecule (SLAM) receptor-binding site and has been implicated in the emergence of highly pathogenic CDV and host switching. These findings demonstrate that giant pandas are susceptible to CDV and suggest that surveillance and vaccination among all captive giant pandas are warranted to support conservation efforts for this endangered species. PMID:27310722

Fatal canine distemper virus infection of giant pandas in China.

PubMed

Feng, Na; Yu, Yicong; Wang, Tiecheng; Wilker, Peter; Wang, Jianzhong; Li, Yuanguo; Sun, Zhe; Gao, Yuwei; Xia, Xianzhu

2016-06-16

We report an outbreak of canine distemper virus (CDV) infection among endangered giant pandas (Ailuropoda melanoleuca). Five of six CDV infected giant pandas died. The surviving giant panda was previously vaccinated against CDV. Genomic sequencing of CDV isolated from one of the infected pandas (giant panda/SX/2014) suggests it belongs to the Asia-1 cluster. The hemagglutinin protein of the isolated virus and virus sequenced from lung samples originating from deceased giant pandas all possessed the substitutions V26M, T213A, K281R, S300N, P340Q, and Y549H. The presence of the Y549H substitution is notable as it is found at the signaling lymphocytic activation molecule (SLAM) receptor-binding site and has been implicated in the emergence of highly pathogenic CDV and host switching. These findings demonstrate that giant pandas are susceptible to CDV and suggest that surveillance and vaccination among all captive giant pandas are warranted to support conservation efforts for this endangered species.

Loose fusion based on SLAM and IMU for indoor environment

NASA Astrophysics Data System (ADS)

Zhu, Haijiang; Wang, Zhicheng; Zhou, Jinglin; Wang, Xuejing

2018-04-01

The simultaneous localization and mapping (SLAM) method based on the RGB-D sensor is widely researched in recent years. However, the accuracy of the RGB-D SLAM relies heavily on correspondence feature points, and the position would be lost in case of scenes with sparse textures. Therefore, plenty of fusion methods using the RGB-D information and inertial measurement unit (IMU) data have investigated to improve the accuracy of SLAM system. However, these fusion methods usually do not take into account the size of matched feature points. The pose estimation calculated by RGB-D information may not be accurate while the number of correct matches is too few. Thus, considering the impact of matches in SLAM system and the problem of missing position in scenes with few textures, a loose fusion method combining RGB-D with IMU is proposed in this paper. In the proposed method, we design a loose fusion strategy based on the RGB-D camera information and IMU data, which is to utilize the IMU data for position estimation when the corresponding point matches are quite few. While there are a lot of matches, the RGB-D information is still used to estimate position. The final pose would be optimized by General Graph Optimization (g2o) framework to reduce error. The experimental results show that the proposed method is better than the RGB-D camera's method. And this method can continue working stably for indoor environment with sparse textures in the SLAM system.

Adaptive Monocular Visual-Inertial SLAM for Real-Time Augmented Reality Applications in Mobile Devices.

PubMed

Piao, Jin-Chun; Kim, Shin-Dug

2017-11-07

Simultaneous localization and mapping (SLAM) is emerging as a prominent issue in computer vision and next-generation core technology for robots, autonomous navigation and augmented reality. In augmented reality applications, fast camera pose estimation and true scale are important. In this paper, we present an adaptive monocular visual-inertial SLAM method for real-time augmented reality applications in mobile devices. First, the SLAM system is implemented based on the visual-inertial odometry method that combines data from a mobile device camera and inertial measurement unit sensor. Second, we present an optical-flow-based fast visual odometry method for real-time camera pose estimation. Finally, an adaptive monocular visual-inertial SLAM is implemented by presenting an adaptive execution module that dynamically selects visual-inertial odometry or optical-flow-based fast visual odometry. Experimental results show that the average translation root-mean-square error of keyframe trajectory is approximately 0.0617 m with the EuRoC dataset. The average tracking time is reduced by 7.8%, 12.9%, and 18.8% when different level-set adaptive policies are applied. Moreover, we conducted experiments with real mobile device sensors, and the results demonstrate the effectiveness of performance improvement using the proposed method.

Scale Estimation and Correction of the Monocular Simultaneous Localization and Mapping (SLAM) Based on Fusion of 1D Laser Range Finder and Vision Data.

PubMed

Zhang, Zhuang; Zhao, Rujin; Liu, Enhai; Yan, Kun; Ma, Yuebo

2018-06-15

This article presents a new sensor fusion method for visual simultaneous localization and mapping (SLAM) through integration of a monocular camera and a 1D-laser range finder. Such as a fusion method provides the scale estimation and drift correction and it is not limited by volume, e.g., the stereo camera is constrained by the baseline and overcomes the limited depth range problem associated with SLAM for RGBD cameras. We first present the analytical feasibility for estimating the absolute scale through the fusion of 1D distance information and image information. Next, the analytical derivation of the laser-vision fusion is described in detail based on the local dense reconstruction of the image sequences. We also correct the scale drift of the monocular SLAM using the laser distance information which is independent of the drift error. Finally, application of this approach to both indoor and outdoor scenes is verified by the Technical University of Munich dataset of RGBD and self-collected data. We compare the effects of the scale estimation and drift correction of the proposed method with the SLAM for a monocular camera and a RGBD camera.

Critical Role of SAP in Progression and Reactivation but Not Maintenance of T Cell-Dependent Humoral Immunity

PubMed Central

2013-01-01

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is a small adaptor molecule mutated in X-linked lymphoproliferative disease, a human immunodeficiency. SAP plays a critical role in the initiation of T cell-dependent B cell responses leading to germinal center reaction, the production of high-affinity antibodies, and B cell memory. However, whether SAP has a role in these responses beyond their initiation is not known. It is important to address this matter not only for mechanistic reasons but also because blockade of the SAP pathway is being contemplated as a means to treat autoimmune diseases in humans. Using an inducibly SAP deficient mouse, we found that SAP was required not only for the initiation but also for the progression of primary T cell-driven B cell responses to haptens. It was also necessary for the reactivation of T cell-dependent B cell immunity during secondary immune responses. These activities consistently correlated with the requirement of SAP for full expression of the lineage commitment factor Bcl-6 in follicular T helper (TFH) cells. However, once memory B cells and long-lived antibody-secreting cells were established, SAP became dispensable for maintaining T cell-dependent B cell responses. Thus, SAP is pivotal for nearly all phases, but not for maintenance, of T cell-driven B cell humoral immunity. These findings may have implications for the treatment of immune disorders by targeting the SAP pathway. PMID:23319045

Critical role of SAP in progression and reactivation but not maintenance of T cell-dependent humoral immunity.

PubMed

Zhong, Ming-Chao; Veillette, André

2013-03-01

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is a small adaptor molecule mutated in X-linked lymphoproliferative disease, a human immunodeficiency. SAP plays a critical role in the initiation of T cell-dependent B cell responses leading to germinal center reaction, the production of high-affinity antibodies, and B cell memory. However, whether SAP has a role in these responses beyond their initiation is not known. It is important to address this matter not only for mechanistic reasons but also because blockade of the SAP pathway is being contemplated as a means to treat autoimmune diseases in humans. Using an inducibly SAP deficient mouse, we found that SAP was required not only for the initiation but also for the progression of primary T cell-driven B cell responses to haptens. It was also necessary for the reactivation of T cell-dependent B cell immunity during secondary immune responses. These activities consistently correlated with the requirement of SAP for full expression of the lineage commitment factor Bcl-6 in follicular T helper (T(FH)) cells. However, once memory B cells and long-lived antibody-secreting cells were established, SAP became dispensable for maintaining T cell-dependent B cell responses. Thus, SAP is pivotal for nearly all phases, but not for maintenance, of T cell-driven B cell humoral immunity. These findings may have implications for the treatment of immune disorders by targeting the SAP pathway.

Nondestructive monitoring damage in composites using scanning laser acoustic microscopy

NASA Technical Reports Server (NTRS)

Wey, A. C.; Kessler, L. W.; Dos Reis, H. L. M.

1992-01-01

Several Nicalon fiber reinforced LAS (lithium alumino-silicate) glass matrix composites were tested to study the relation between the residual strength and the different amounts of damage. The samples were fatigued by four-point cyclic loading at a 5 Hz rate at 500 C for a different number of cycles. 10 MHz scanning laser acoustic microscope (SLAM) images were taken to monitor damage on the samples. Our SLAM results indicate that there were defects already existing throughout the sample before fatigue, and the resultant damage pattern from fatigue could be related to the initial defect distribution in the sample. Finally, the fatigued samples were fractured and the residual strength data could not be explained by the cyclic fatigue alone. Rather, the damage patterns evident in the SLAM images were needed to explain the scatter in the data. The results show that SLAM is useful in nondestructively monitoring damage and estimating residual strength of fatigued ceramic composites.

Rotational and frictional dynamics of the slamming of a door

NASA Astrophysics Data System (ADS)

Klein, Pascal; Müller, Andreas; Gröber, Sebastian; Molz, Alexander; Kuhn, Jochen

2017-01-01

A theoretical and experimental investigation of the rotational dynamics, including friction, of a slamming door is presented. Based on existing work regarding different damping models for rotational and oscillatory motions, we examine different forms for the (angular) velocity dependence (ωn, n = 0, 1, 2) of the frictional force. An analytic solution is given when all three friction terms are present and several solutions for specific cases known from the literature are reproduced. The motion of a door is investigated experimentally using a smartphone, and the data are compared with the theoretical results. A laboratory experiment under more controlled conditions is conducted to gain a deeper understanding of the movement of a slammed door. Our findings provide quantitative evidence that damping models involving quadratic air drag are most appropriate for the slamming of a door. Examining this everyday example of a physical phenomenon increases student motivation, because they can relate it to their own personal experience.

Adaptive Monocular Visual–Inertial SLAM for Real-Time Augmented Reality Applications in Mobile Devices

PubMed Central

Piao, Jin-Chun; Kim, Shin-Dug

2017-01-01

Simultaneous localization and mapping (SLAM) is emerging as a prominent issue in computer vision and next-generation core technology for robots, autonomous navigation and augmented reality. In augmented reality applications, fast camera pose estimation and true scale are important. In this paper, we present an adaptive monocular visual–inertial SLAM method for real-time augmented reality applications in mobile devices. First, the SLAM system is implemented based on the visual–inertial odometry method that combines data from a mobile device camera and inertial measurement unit sensor. Second, we present an optical-flow-based fast visual odometry method for real-time camera pose estimation. Finally, an adaptive monocular visual–inertial SLAM is implemented by presenting an adaptive execution module that dynamically selects visual–inertial odometry or optical-flow-based fast visual odometry. Experimental results show that the average translation root-mean-square error of keyframe trajectory is approximately 0.0617 m with the EuRoC dataset. The average tracking time is reduced by 7.8%, 12.9%, and 18.8% when different level-set adaptive policies are applied. Moreover, we conducted experiments with real mobile device sensors, and the results demonstrate the effectiveness of performance improvement using the proposed method. PMID:29112143

Radar Based Navigation in Unknown Terrain

DTIC Science & Technology

2012-12-31

localization and mapping ( SLAM ) approach. The radar processing algorithms detect strong, persistent, and stationary reflectors embedded in the...Global System for Mobile Communications . . . . . . . . . 2 LIDAR Light Detection and Ranging . . . . . . . . . . . . . . . . 2 SAR Synthetic Aperture...22 SLAM Simultaneous Localization and Mapping . . . . . . . . . . 25 FDM Frequency Division Multiplexing

Robotic path-finding in inverse treatment planning for stereotactic radiosurgery with continuous dose delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vandewouw, Marlee M., E-mail: marleev@mie.utoronto

Purpose: Continuous dose delivery in radiation therapy treatments has been shown to decrease total treatment time while improving the dose conformity and distribution homogeneity over the conventional step-and-shoot approach. The authors develop an inverse treatment planning method for Gamma Knife® Perfexion™ that continuously delivers dose along a path in the target. Methods: The authors’ method is comprised of two steps: find a path within the target, then solve a mixed integer optimization model to find the optimal collimator configurations and durations along the selected path. Robotic path-finding techniques, specifically, simultaneous localization and mapping (SLAM) using an extended Kalman filter, aremore » used to obtain a path that travels sufficiently close to selected isocentre locations. SLAM is novelly extended to explore a 3D, discrete environment, which is the target discretized into voxels. Further novel extensions are incorporated into the steering mechanism to account for target geometry. Results: The SLAM method was tested on seven clinical cases and compared to clinical, Hamiltonian path continuous delivery, and inverse step-and-shoot treatment plans. The SLAM approach improved dose metrics compared to the clinical plans and Hamiltonian path continuous delivery plans. Beam-on times improved over clinical plans, and had mixed performance compared to Hamiltonian path continuous plans. The SLAM method is also shown to be robust to path selection inaccuracies, isocentre selection, and dose distribution. Conclusions: The SLAM method for continuous delivery provides decreased total treatment time and increased treatment quality compared to both clinical and inverse step-and-shoot plans, and outperforms existing path methods in treatment quality. It also accounts for uncertainty in treatment planning by accommodating inaccuracies.« less

An evaluation of attention models for use in SLAM

NASA Astrophysics Data System (ADS)

Dodge, Samuel; Karam, Lina

2013-12-01

In this paper we study the application of visual saliency models for the simultaneous localization and mapping (SLAM) problem. We consider visual SLAM, where the location of the camera and a map of the environment can be generated using images from a single moving camera. In visual SLAM, the interest point detector is of key importance. This detector must be invariant to certain image transformations so that features can be matched across di erent frames. Recent work has used a model of human visual attention to detect interest points, however it is unclear as to what is the best attention model for this purpose. To this aim, we compare the performance of interest points from four saliency models (Itti, GBVS, RARE, and AWS) with the performance of four traditional interest point detectors (Harris, Shi-Tomasi, SIFT, and FAST). We evaluate these detectors under several di erent types of image transformation and nd that the Itti saliency model, in general, achieves the best performance in terms of keypoint repeatability.

Clinical composite measures of disease activity and damage used to evaluate patients with systemic lupus erythematosus: A systematic literature review.

PubMed

Castrejón, Isabel; Rúa-Figueroa, Iñigo; Rosario, María Piedad; Carmona, Loreto

2014-01-01

To determine the most appropriate indices to evaluate the disease activity and damage in patients with sytemic lupus erythematosus (SLE). A systematic literature search was performed to identify validation studies of indices used to evaluate disease activity and damage. We collected information for each instrument on every aspect of validation including feasibility, reliability, validity and sensitivity to change using ad hoc forms. A total of 38 articles were included addressing the validation of 6 composite indices to evaluate disease activity (BILAG, ECLAM, SLAM, SLEDAI, LAI and SLAQ); and 3 indices to evaluate damage (SLICC/ACE-DI, LDIQ and BILD). Only the SLAQ, LIDIQ and the BILD were self-administered. Feasibility and internal consistency was only studied in 3 indices (BILAG, SLAQ and SDI) with a Cronbach's α ranging from 0.35 to 0.87. The intra-observer reliability was examined by the intraclass correlation coefficient for BILAG with a result of 0.48 (95%CI: 0,23-0,81) and using analysis of variance for SLAM-R (0,78), SLEDAI (0,33) and the LAI (0,81). The inter-observer feasibility was evaluated using the correlation coefficient for ECLAM (0,90-0,93), the SLAM (0,86) and MEX-SLEDAI (0,97-0,89). The construct validity was examined by means of convergence with other instruments, specifically with global assessment by the physician, with similar results between indices (0,48-0,75). Lastly, responsiveness was tested in all indices except LAI, SDI and LDIQ, with a standardized response mean ranging from 0.12 to 0.75. Although multiple instruments have been validated for use in SLE it was not possible to find direct evidence of which is the most appropriate. BILAG and SLEDAI, with moderate feasibility and low responsiveness, are the 2 indices with a most complete validation and more extensively used. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Nutrient sampling slam: high resolution surface-water sampling in streams reveals patterns in groundwater chemistry and flow paths

EPA Science Inventory

The groundwater–surface water interface (GSWI), consisting of shallow groundwater adjacent to stream channels, is a hot spot for nitrogen removal processes, a storage zone for other solutes, and a target for restoration activities. Characterizing groundwater-surface water intera...

Antigen Specific Responses and ANA production in B6.Sle1b mice: A role for SAP

PubMed Central

Jennings, Paula; Chan, Alice; Schwartzberg, Pamela; Wakeland, Edward K.; Yuan, Dorothy

2010-01-01

B6.Sle1b mice, which contain the Sle1b gene interval derived from lupus prone NZM2410 mice on a C57BL/6 background, present with gender-biased, highly penetrant anti-nuclear antibody (ANA) production. To obtain some insight into the possible induction mechanism of autoantibodies in these mice we compared antigen specific T dependent (TD) and T independent (TI-II) responses between B6.Sle1b and B6 mice before the development of high ANA titers. Our results show that B6.Sle1b mice mount enhanced responses to a TI-II antigen. Additionally, the memory T cell response generated by a TD antigen was also increased. This enhancement correlates with the greater ability of B cells from B6.Sle1b mice to present antigen to T cells. The SLAM Associated Protein (SAP) is critical for signaling of many of the molecules encoded by the SLAM/CD2 gene cluster, candidates for mediating the Sle1b phenotype; therefore, we also investigated the effect of sap deletion in these strains on the TD and TI-II responses as well as on ANA production. The results of these studies of responses to non-self antigens provide further insight for the mechanism by which responses to self-antigens might be initiated in the context of specific genetic alterations. PMID:18845419

Two Dimensional Positioning and Heading Solution for Flying Vehicles using a Line-Scanning Laser Radar (LADAR)

DTIC Science & Technology

2011-03-24

6 2.4.1 Reference Frames . . . . . . . . . . . . . . . . . 6 2.4.2 Line and Feature Extraction . . . . . . . . . . . 7 2.4.3 SLAM ...Positioning System . . . . . . . . . . . . . . . . . . 1 LADAR Laser Radar . . . . . . . . . . . . . . . . . . . . . . . . . . 1 LiDAR Light Detection and...Ranging . . . . . . . . . . . . . . . . 2 SLAM Simultaneous Localization and Mapping . . . . . . . . . . 2 ANT Advanced Navigation Technology

SLAM examination of solar cells and solar cell welds. [Scanning Laser Acoustic Microscope

NASA Technical Reports Server (NTRS)

Stella, P. M.; Vorres, C. L.; Yuhas, D. E.

1981-01-01

The scanning laser acoustic microscope (SLAM) has been evaluated for non-destructive examination of solar cells and interconnector bonds. Using this technique, it is possible to view through materials in order to reveal regions of discontinuity such as microcracks and voids. Of particular interest is the ability to evaluate, in a unique manner, the bonds produced by parallel gap welding. It is possible to not only determine the area and geometry of the bond between the tab and cell, but also to reveal any microcracks incurred during the welding. By correlating the SLAM results with conventional techniques of weld evaluation a more confident weld parameter optimization can be obtained.

FOXP3 renders activated human regulatory T cells resistant to restimulation-induced cell death by suppressing SAP expression.

PubMed

Katz, Gil; Voss, Kelsey; Yan, Toria F; Kim, Yong Chan; Kortum, Robert L; Scott, David W; Snow, Andrew L

2018-05-01

Restimulation-induced cell death (RICD) is an apoptotic program that regulates effector T cell expansion, triggered by repeated stimulation through the T cell receptor (TCR) in the presence of interleukin-2 (IL-2). Although CD4 + regulatory T cells (Tregs) consume IL-2 and experience frequent TCR stimulation, they are highly resistant to RICD. Resistance in Tregs is dependent on the forkhead box P3 (FOXP3) transcription factor, although the mechanism remains unclear. T cells from patients with X-linked lymphoproliferative disease (XLP-1), that lack the adaptor molecule SLAM-associated protein (SAP), are also resistant to RICD. Here we demonstrate that normal Tregs express very low levels of SAP compared to conventional T cells. FOXP3 reduces SAP expression by directly binding to and repressing the SH2D1A (SAP) promoter. Indeed, ectopic SAP expression restores RICD sensitivity in human FOXP3 + Tregs. Our findings illuminate the mechanism behind FOXP3-mediated RICD resistance in Tregs, providing new insight into their long-term persistence. Published by Elsevier Inc.

Measles Virus Persistent Infection of Human Induced Pluripotent Stem Cells.

PubMed

Naaman, Hila; Rabinski, Tatiana; Yizhak, Avi; Mizrahi, Solly; Avni, Yonat Shemer; Taube, Ran; Rager, Bracha; Weinstein, Yacov; Rall, Glenn; Gopas, Jacob; Ofir, Rivka

2018-02-01

In this study, we found that the measles virus (MV) can infect human-induced pluripotent stem cells (hiPSCs). Wild-type MV strains generally use human signaling lymphocyte activation molecule (SLAM; CD150) as a cellular receptor, while vaccine strains such as the Edmonston strain can use both CD150 and CD46 as receptors. It is not yet known how early in the embryonal differentiation stages these receptors are expressed. We established two hiPSCs (BGU-iPSCs and EMF-iPSCs) which express CD46 and CD150. Both cell types can be infected by MV to form persistent, noncytopathic cell lines that release infectious MV particles. Following MV persistent infection, BGU-iPSCs and EMF-iPSCs remain pluripotent and can differentiate in vitro into the three germ layers. This includes cells expressing the neuronal differentiation markers: NF68 and miRNA-124. Since the MV does not integrate into the cell's genome, it can be utilized as a vehicle to systematically introduce genes into iPSC, to dissect and to define factors regulating lineage differentiation.

Bridging Philosophy of Technology and Neurobiological Research: Interpreting Images from the "Slam Freezer"

ERIC Educational Resources Information Center

Rosenberger, Robert

2005-01-01

The swiftly growing field of neurobiological research utilizes highly advanced technologies (e.g., magnetic resonance imaging, electron microscopy) to mediate between investigators and the brains they investigate. Here, the author analyzes a device called the "slam freezer" that quick-freezes neurons to be studied under the microscope. Employing…

ION INJECTION AT QUASI-PARALLEL SHOCKS SEEN BY THE CLUSTER SPACECRAFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johlander, A.; Vaivads, A.; Khotyaintsev, Yu. V.

2016-01-20

Collisionless shocks in space plasma are known to be capable of accelerating ions to very high energies through diffusive shock acceleration (DSA). This process requires an injection of suprathermal ions, but the mechanisms producing such a suprathermal ion seed population are still not fully understood. We study acceleration of solar wind ions resulting from reflection off short large-amplitude magnetic structures (SLAMSs) in the quasi-parallel bow shock of Earth using in situ data from the four Cluster spacecraft. Nearly specularly reflected solar wind ions are observed just upstream of a SLAMS. The reflected ions are undergoing shock drift acceleration (SDA) andmore » obtain energies higher than the solar wind energy upstream of the SLAMS. Our test particle simulations show that solar wind ions with lower energy are more likely to be reflected off the SLAMS, while high-energy ions pass through the SLAMS, which is consistent with the observations. The process of SDA at SLAMSs can provide an effective way of accelerating solar wind ions to suprathermal energies. Therefore, this could be a mechanism of ion injection into DSA in astrophysical plasmas.« less

Behavior Analysis of Novel Wearable Indoor Mapping System Based on 3D-SLAM.

PubMed

Lagüela, Susana; Dorado, Iago; Gesto, Manuel; Arias, Pedro; González-Aguilera, Diego; Lorenzo, Henrique

2018-03-02

This paper presents a Wearable Prototype for indoor mapping developed by the University of Vigo. The system is based on a Velodyne LiDAR, acquiring points with 16 rays for a simplistic or low-density 3D representation of reality. With this, a Simultaneous Localization and Mapping (3D-SLAM) method is developed for the mapping and generation of 3D point clouds of scenarios deprived from GNSS signal. The quality of the system presented is validated through the comparison with a commercial indoor mapping system, Zeb-Revo, from the company GeoSLAM and with a terrestrial LiDAR, Faro Focus 3D X330. The first is considered as a relative reference with other mobile systems and is chosen due to its use of the same principle for mapping: SLAM techniques based on Robot Operating System (ROS), while the second is taken as ground-truth for the determination of the final accuracy of the system regarding reality. Results show that the accuracy of the system is mainly determined by the accuracy of the sensor, with little increment in the error introduced by the mapping algorithm.

Drift-Free Indoor Navigation Using Simultaneous Localization and Mapping of the Ambient Heterogeneous Magnetic Field

NASA Astrophysics Data System (ADS)

Chow, J. C. K.

2017-09-01

In the absence of external reference position information (e.g. surveyed targets or Global Navigation Satellite Systems) Simultaneous Localization and Mapping (SLAM) has proven to be an effective method for indoor navigation. The positioning drift can be reduced with regular loop-closures and global relaxation as the backend, thus achieving a good balance between exploration and exploitation. Although vision-based systems like laser scanners are typically deployed for SLAM, these sensors are heavy, energy inefficient, and expensive, making them unattractive for wearables or smartphone applications. However, the concept of SLAM can be extended to non-optical systems such as magnetometers. Instead of matching features such as walls and furniture using some variation of the Iterative Closest Point algorithm, the local magnetic field can be matched to provide loop-closure and global trajectory updates in a Gaussian Process (GP) SLAM framework. With a MEMS-based inertial measurement unit providing a continuous trajectory, and the matching of locally distinct magnetic field maps, experimental results in this paper show that a drift-free navigation solution in an indoor environment with millimetre-level accuracy can be achieved. The GP-SLAM approach presented can be formulated as a maximum a posteriori estimation problem and it can naturally perform loop-detection, feature-to-feature distance minimization, global trajectory optimization, and magnetic field map estimation simultaneously. Spatially continuous features (i.e. smooth magnetic field signatures) are used instead of discrete feature correspondences (e.g. point-to-point) as in conventional vision-based SLAM. These position updates from the ambient magnetic field also provide enough information for calibrating the accelerometer bias and gyroscope bias in-use. The only restriction for this method is the need for magnetic disturbances (which is typically not an issue for indoor environments); however, no assumptions are required for the general motion of the sensor (e.g. static periods).

Cell-to-Cell Measles Virus Spread between Human Neurons Is Dependent on Hemagglutinin and Hyperfusogenic Fusion Protein.

PubMed

Sato, Yuma; Watanabe, Shumpei; Fukuda, Yoshinari; Hashiguchi, Takao; Yanagi, Yusuke; Ohno, Shinji

2018-03-15

Measles virus (MV) usually causes acute infection but in rare cases persists in the brain, resulting in subacute sclerosing panencephalitis (SSPE). Since human neurons, an important target affected in the disease, do not express the known MV receptors (signaling lymphocyte activation molecule [SLAM] and nectin 4), how MV infects neurons and spreads between them is unknown. Recent studies have shown that many virus strains isolated from SSPE patients possess substitutions in the extracellular domain of the fusion (F) protein which confer enhanced fusion activity. Hyperfusogenic viruses with such mutations, unlike the wild-type MV, can induce cell-cell fusion even in SLAM- and nectin 4-negative cells and spread efficiently in human primary neurons and the brains of animal models. We show here that a hyperfusogenic mutant MV, IC323-F(T461I)-EGFP (IC323 with a fusion-enhancing T461I substitution in the F protein and expressing enhanced green fluorescent protein), but not the wild-type MV, spreads in differentiated NT2 cells, a widely used human neuron model. Confocal time-lapse imaging revealed the cell-to-cell spread of IC323-F(T461I)-EGFP between NT2 neurons without syncytium formation. The production of virus particles was strongly suppressed in NT2 neurons, also supporting cell-to-cell viral transmission. The spread of IC323-F(T461I)-EGFP was inhibited by a fusion inhibitor peptide as well as by some but not all of the anti-hemagglutinin antibodies which neutralize SLAM- or nectin-4-dependent MV infection, suggesting the presence of a distinct neuronal receptor. Our results indicate that MV spreads in a cell-to-cell manner between human neurons without causing syncytium formation and that the spread is dependent on the hyperfusogenic F protein, the hemagglutinin, and the putative neuronal receptor for MV. IMPORTANCE Measles virus (MV), in rare cases, persists in the human central nervous system (CNS) and causes subacute sclerosing panencephalitis (SSPE) several years after acute infection. This neurological complication is almost always fatal, and there is currently no effective treatment for it. Mechanisms by which MV invades the CNS and causes the disease remain to be elucidated. We have previously shown that fusion-enhancing substitutions in the fusion protein of MVs isolated from SSPE patients contribute to MV spread in neurons. In this study, we demonstrate that MV bearing the hyperfusogenic mutant fusion protein spreads between human neurons in a cell-to-cell manner. Spread of the virus was inhibited by a fusion inhibitor peptide and antibodies against the MV hemagglutinin, indicating that both the hemagglutinin and hyperfusogenic fusion protein play important roles in MV spread between human neurons. The findings help us better understand the disease process of SSPE. Copyright © 2018 American Society for Microbiology.

Measles Virus Enters Breast and Colon Cancer Cell Lines through a PVRL4-Mediated Macropinocytosis Pathway

PubMed Central

Delpeut, Sebastien; Sisson, Gary; Black, Karen M.

2017-01-01

ABSTRACT Measles virus (MeV) is a member of the family Paramixoviridae that causes a highly contagious respiratory disease but has emerged as a promising oncolytic platform. Previous studies of MeV entry focused on the identification of cellular receptors. However, the endocytic and trafficking pathways utilized during MeV entry remain poorly described. The contribution of each endocytic pathway has been examined in cells that express the MeV receptors SLAM (signaling lymphocyte-activating molecule) and PVRL4 (poliovirus receptor-like 4) (nectin-4). Recombinant MeVs expressing either firefly luciferase or green fluorescent protein together with a variety of inhibitors were used. The results showed that MeV uptake was dynamin independent in the Vero.hPVRL4, Vero.hSLAM, and PVRL4-positive MCF7 breast cancer cell lines. However, MeV infection was blocked by 5-(N-ethyl-N-propyl)amiloride (EIPA), the hallmark inhibitor of macropinocytosis, as well as inhibitors of actin polymerization. By using phalloidin staining, MeV entry was shown to induce actin rearrangements and the formation of membrane ruffles accompanied by transient elevated fluid uptake. Small interfering RNA (siRNA) knockdown of p21-activated kinase 1 (PAK1) demonstrated that MeV enters both Vero.hPVRL4 and Vero.hSLAM cells in a PAK1-independent manner using a macropinocytosis-like pathway. In contrast, MeV entry into MCF7 human breast cancer cells relied upon Rac1 and its effector PAK1 through a PVRL4-mediated macropinocytosis pathway. MeV entry into DLD-1 colon and HTB-20 breast cancer cells also appeared to use the same pathway. Overall, these findings provide new insight into the life cycle of MeV, which could lead to therapies that block virus entry or methods that improve the uptake of MeV by cancer cells during oncolytic therapy. IMPORTANCE In the past decades, measles virus (MeV) has emerged as a promising oncolytic platform. Previous studies concerning MeV entry focused mainly on the identification of putative receptors for MeV. Nectin-4 (PVRL4) was recently identified as the epithelial cell receptor for MeV. However, the specific endocytic and trafficking pathways utilized during MeV infections are poorly documented. In this study, we demonstrated that MeV enters host cells via a dynamin-independent and actin-dependent endocytic pathway. Moreover, we show that MeV gains entry into MCF7, DLD-1, and HTB-20 cancer cells through a PVRL4-mediated macropinocytosis pathway and identified the typical cellular GTPase and kinase involved. Our findings provide new insight into the life cycle of MeV, which may lead to the development of therapies that block the entry of the virus into the host cell or alternatively promote the uptake of oncolytic MeV into cancer cells. PMID:28250131

SLAM algorithm applied to robotics assistance for navigation in unknown environments.

PubMed

Cheein, Fernando A Auat; Lopez, Natalia; Soria, Carlos M; di Sciascio, Fernando A; Pereira, Fernando Lobo; Carelli, Ricardo

2010-02-17

The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM) algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous). The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI). In this paper, a sequential Extended Kalman Filter (EKF) feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how to use the MCI. The SLAM results have shown a consistent reconstruction of the environment. The obtained map was stored inside the Muscle-Computer Interface. The integration of a highly demanding processing algorithm (SLAM) with a MCI and the communication between both in real time have shown to be consistent and successful. The metric map generated by the mobile robot would allow possible future autonomous navigation without direct control of the user, whose function could be relegated to choose robot destinations. Also, the mobile robot shares the same kinematic model of a motorized wheelchair. This advantage can be exploited for wheelchair autonomous navigation.

Fermilab Today

Science.gov Websites

and upcoming conferences at Fermilab Campaigns Take Five Weather Weather Chance of showers 62°/59 ., five of Fermilab's best and brightest will duke it out in the Fermilab Arts and Lecture Series Physics Slam 2013. The event is similar to a poetry slam - each of the five physicists will get 10 minutes to

Our Lyrics Will Not Be on Lockdown: An Arts Collective's Response to an Incarceration Nation

ERIC Educational Resources Information Center

Green, Keisha

2010-01-01

Recognizing the unprecedented proliferation of prisons in the United States, Blackout Arts Collective (BAC), a grassroots organization working to empower communities of color through the arts, education, and activism, launched a national tour--"Lyrics on Lockdown (LOL): Slamming the Prison Industrial Complex." As a BAC member, I participated in…

Fermilab Education Office - Director's Award

Science.gov Websites

. He has given Ask-A-Scientist lectures, talked at the Family Open House, performed in the Physics Slam , and given tours for Saturday Morning Physics. He is active in our K–12 programs and beyond by Saturday Morning Physics program has engendered a love of physics in thousands of high school students

Slam and the Citizen Orator: Teaching Civic Oration and Engagement through Spoken Word

ERIC Educational Resources Information Center

Wells, Celeste C.; DeLeon, Daniel

2015-01-01

The activity described in this paper was developed in response to the experience of teaching a large lecture introduction course to freshman and sophomore undergraduates called "The Rhetorical Tradition." This course covers, roughly, the last 2500 years of rhetoric. One of the issues faced in this course is that students struggle to…

Towards a Pedagogical Model for Science Education: Bridging Educational Contexts through a Blended Learning Approach

ERIC Educational Resources Information Center

Bidarra, José; Rusman, Ellen

2017-01-01

This paper proposes a design framework to support science education through blended learning, based on a participatory and interactive approach supported by ICT-based tools, called "Science Learning Activities Model" (SLAM). The development of this design framework started as a response to complex changes in society and education (e.g.…

Line Segmentation of 2d Laser Scanner Point Clouds for Indoor Slam Based on a Range of Residuals

NASA Astrophysics Data System (ADS)

Peter, M.; Jafri, S. R. U. N.; Vosselman, G.

2017-09-01

Indoor mobile laser scanning (IMLS) based on the Simultaneous Localization and Mapping (SLAM) principle proves to be the preferred method to acquire data of indoor environments at a large scale. In previous work, we proposed a backpack IMLS system containing three 2D laser scanners and an according SLAM approach. The feature-based SLAM approach solves all six degrees of freedom simultaneously and builds on the association of lines to planes. Because of the iterative character of the SLAM process, the quality and reliability of the segmentation of linear segments in the scanlines plays a crucial role in the quality of the derived poses and consequently the point clouds. The orientations of the lines resulting from the segmentation can be influenced negatively by narrow objects which are nearly coplanar with walls (like e.g. doors) which will cause the line to be tilted if those objects are not detected as separate segments. State-of-the-art methods from the robotics domain like Iterative End Point Fit and Line Tracking were found to not handle such situations well. Thus, we describe a novel segmentation method based on the comparison of a range of residuals to a range of thresholds. For the definition of the thresholds we employ the fact that the expected value for the average of residuals of n points with respect to the line is σ / √n. Our method, as shown by the experiments and the comparison to other methods, is able to deliver more accurate results than the two approaches it was tested against.

Algorithmic Approaches for Place Recognition in Featureless, Walled Environments

DTIC Science & Technology

2015-01-01

inertial measurement unit LIDAR light detection and ranging RANSAC random sample consensus SLAM simultaneous localization and mapping SUSAN smallest...algorithm 38 21 Typical input image for general junction based algorithm 39 22 Short exposure image of hallway junction taken by LIDAR 40 23...discipline of simultaneous localization and mapping ( SLAM ) has been studied intensively over the past several years. Many technical approaches

Behavior Analysis of Novel Wearable Indoor Mapping System Based on 3D-SLAM

PubMed Central

Dorado, Iago; Gesto, Manuel; Arias, Pedro; Lorenzo, Henrique

2018-01-01

This paper presents a Wearable Prototype for indoor mapping developed by the University of Vigo. The system is based on a Velodyne LiDAR, acquiring points with 16 rays for a simplistic or low-density 3D representation of reality. With this, a Simultaneous Localization and Mapping (3D-SLAM) method is developed for the mapping and generation of 3D point clouds of scenarios deprived from GNSS signal. The quality of the system presented is validated through the comparison with a commercial indoor mapping system, Zeb-Revo, from the company GeoSLAM and with a terrestrial LiDAR, Faro Focus3D X330. The first is considered as a relative reference with other mobile systems and is chosen due to its use of the same principle for mapping: SLAM techniques based on Robot Operating System (ROS), while the second is taken as ground-truth for the determination of the final accuracy of the system regarding reality. Results show that the accuracy of the system is mainly determined by the accuracy of the sensor, with little increment in the error introduced by the mapping algorithm. PMID:29498715

Robust feature tracking for endoscopic pose estimation and structure recovery

NASA Astrophysics Data System (ADS)

Speidel, S.; Krappe, S.; Röhl, S.; Bodenstedt, S.; Müller-Stich, B.; Dillmann, R.

2013-03-01

Minimally invasive surgery is a highly complex medical discipline with several difficulties for the surgeon. To alleviate these difficulties, augmented reality can be used for intraoperative assistance. For visualization, the endoscope pose must be known which can be acquired with a SLAM (Simultaneous Localization and Mapping) approach using the endoscopic images. In this paper we focus on feature tracking for SLAM in minimally invasive surgery. Robust feature tracking and minimization of false correspondences is crucial for localizing the endoscope. As sensory input we use a stereo endoscope and evaluate different feature types in a developed SLAM framework. The accuracy of the endoscope pose estimation is validated with synthetic and ex vivo data. Furthermore we test the approach with in vivo image sequences from da Vinci interventions.

SLAM algorithm applied to robotics assistance for navigation in unknown environments

PubMed Central

2010-01-01

Background The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM) algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous). The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI). Methods In this paper, a sequential Extended Kalman Filter (EKF) feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. Results The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how to use the MCI. The SLAM results have shown a consistent reconstruction of the environment. The obtained map was stored inside the Muscle-Computer Interface. Conclusions The integration of a highly demanding processing algorithm (SLAM) with a MCI and the communication between both in real time have shown to be consistent and successful. The metric map generated by the mobile robot would allow possible future autonomous navigation without direct control of the user, whose function could be relegated to choose robot destinations. Also, the mobile robot shares the same kinematic model of a motorized wheelchair. This advantage can be exploited for wheelchair autonomous navigation. PMID:20163735

Computational Analysis of the Interaction Energies between Amino Acid Residues of the Measles Virus Hemagglutinin and Its Receptors.

PubMed

Xu, Fengqi; Tanaka, Shigenori; Watanabe, Hirofumi; Shimane, Yasuhiro; Iwasawa, Misako; Ohishi, Kazue; Maruyama, Tadashi

2018-05-03

Measles virus (MV) causes an acute and highly devastating contagious disease in humans. Employing the crystal structures of three human receptors, signaling lymphocyte-activation molecule (SLAM), CD46, and Nectin-4, in complex with the measles virus hemagglutinin (MVH), we elucidated computationally the details of binding energies between the amino acid residues of MVH and those of the receptors with an ab initio fragment molecular orbital (FMO) method. The calculated inter-fragment interaction energies (IFIEs) revealed a number of significantly interacting amino acid residues of MVH that played essential roles in binding to the receptors. As predicted from previously reported experiments, some important amino-acid residues of MVH were shown to be common but others were specific to interactions with the three receptors. Particularly, some of the (non-polar) hydrophobic residues of MVH were found to be attractively interacting with multiple receptors, thus indicating the importance of the hydrophobic pocket for intermolecular interactions (especially in the case of Nectin-4). In contrast, the electrostatic interactions tended to be used for specific molecular recognition. Furthermore, we carried out FMO calculations for in silico experiments of amino acid mutations, finding reasonable agreements with virological experiments concerning the substitution effect of residues. Thus, the present study demonstrates that the electron-correlated FMO method is a powerful tool to search exhaustively for amino acid residues that contribute to interactions with receptor molecules. It is also applicable for designing inhibitors of MVH and engineered MVs for cancer therapy.

Multiple Integrated Navigation Sensors for Improved Occupancy Grid FastSLAM

DTIC Science & Technology

2011-03-01

to the Faculty Department of Electrical and Computer Engineering Graduate School of Engineering and Management Air Force Institute of Technology Air...autonomous vehicle exploration with applications to search and rescue. To current knowledge , this research presents the first SLAM solution to...solution is a key component of an autonomous vehicle, especially one whose mission involves gaining knowledge of unknown areas. It provides the ability

Seismo-Lineament Analysis Method (SLAM) Applied to the South Napa Earthquake

NASA Astrophysics Data System (ADS)

Worrell, V. E.; Cronin, V. S.

2014-12-01

We used the seismo-lineament analysis method (SLAM; http://bearspace.baylor.edu/Vince_Cronin/www/SLAM/) to "predict" the location of the fault that produced the M 6.0 South Napa earthquake of 24 August 2014, using hypocenter and focal mechanism data from NCEDC (http://www.ncedc.org/ncedc/catalog-search.html) and a digital elevation model from the USGS National Elevation Dataset (http://viewer.nationalmap.gov/viewer/). The ground-surface trace of the causative fault (i.e., the Browns Valley strand of the West Napa fault zone; Bryant, 2000, 1982) and virtually all of the ground-rupture sites reported by the USGS and California Geological Survey (http://www.eqclearinghouse.org/2014-08-24-south-napa/) were located within the north-striking seismo-lineament. We also used moment tensors published online by the USGS and GCMT (http://comcat.cr.usgs.gov/earthquakes/eventpage/nc72282711#scientific_moment-tensor) as inputs to SLAM and found that their northwest-striking seismo-lineaments correlated spatially with the causative fault. We concluded that SLAM could have been used as soon as these mechanism solutions were available to help direct the search for the trace of the causative fault and possible rupture-related damage. We then considered whether the seismogenic fault could have been identified using SLAM prior to the 24 August event, based on the focal mechanisms of smaller prior earthquakes reported by the NCEDC or ISC (http://www.isc.ac.uk). Seismo-lineaments from three M~3.5 events from 1990 and 2012, located in the Vallejo-Crockett area, correlate spatially with the Napa County Airport strand of the West Napa fault and extend along strike toward the Browns Valley strand (Bryant, 2000, 1982). Hence, we might have used focal mechanisms from smaller earthquakes to establish that the West Napa fault is likely seismogenic prior to the South Napa earthquake. Early recognition that a fault with a mapped ground-surface trace is seismogenic, based on smaller earthquakes, can facilitate appropriate preparatory work to minimize damage during a larger-magnitude event.

Cohort profile of the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Case Register: current status and recent enhancement of an Electronic Mental Health Record-derived data resource.

PubMed

Perera, Gayan; Broadbent, Matthew; Callard, Felicity; Chang, Chin-Kuo; Downs, Johnny; Dutta, Rina; Fernandes, Andrea; Hayes, Richard D; Henderson, Max; Jackson, Richard; Jewell, Amelia; Kadra, Giouliana; Little, Ryan; Pritchard, Megan; Shetty, Hitesh; Tulloch, Alex; Stewart, Robert

2016-03-01

The South London and Maudsley National Health Service (NHS) Foundation Trust Biomedical Research Centre (SLaM BRC) Case Register and its Clinical Record Interactive Search (CRIS) application were developed in 2008, generating a research repository of real-time, anonymised, structured and open-text data derived from the electronic health record system used by SLaM, a large mental healthcare provider in southeast London. In this paper, we update this register's descriptive data, and describe the substantial expansion and extension of the data resource since its original development. Descriptive data were generated from the SLaM BRC Case Register on 31 December 2014. Currently, there are over 250,000 patient records accessed through CRIS. Since 2008, the most significant developments in the SLaM BRC Case Register have been the introduction of natural language processing to extract structured data from open-text fields, linkages to external sources of data, and the addition of a parallel relational database (Structured Query Language) output. Natural language processing applications to date have brought in new and hitherto inaccessible data on cognitive function, education, social care receipt, smoking, diagnostic statements and pharmacotherapy. In addition, through external data linkages, large volumes of supplementary information have been accessed on mortality, hospital attendances and cancer registrations. Coupled with robust data security and governance structures, electronic health records provide potentially transformative information on mental disorders and outcomes in routine clinical care. The SLaM BRC Case Register continues to grow as a database, with approximately 20,000 new cases added each year, in addition to extension of follow-up for existing cases. Data linkages and natural language processing present important opportunities to enhance this type of research resource further, achieving both volume and depth of data. However, research projects still need to be carefully tailored, so that they take into account the nature and quality of the source information. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Multi-Robot FastSLAM for Large Domains

DTIC Science & Technology

2007-03-01

Derr, D. Fox, A.B. Cremers , Integrating global position estimation and position tracking for mobile robots: The dynamic markov localization approach...Intelligence (AAAI), 2000. 53. Andrew J. Davison and David W. Murray. Simultaneous Localization and Map- Building Using Active Vision. IEEE...Wyeth, Michael Milford and David Prasser. A Modified Particle Filter for Simultaneous Robot Localization and Landmark Tracking in an Indoor

Using external sensors in solution of SLAM task

NASA Astrophysics Data System (ADS)

Provkov, V. S.; Starodubtsev, I. S.

2018-05-01

This article describes the algorithms of spatial orientation of SLAM, PTAM and their positive and negative sides. Based on the SLAM method, a method that uses an RGBD camera and additional sensors was developed: an accelerometer, a gyroscope, and a magnetometer. The investigated orientation methods have their advantages when moving along a straight trajectory or when rotating a moving platform. As a result of experiments and a weighted linear combination of the positions obtained from data of the RGBD camera and the nine-axis sensor, it became possible to improve the accuracy of the original algorithm even using a constant as a weight function. In the future, it is planned to develop an algorithm for the dynamic construction of a weight function, as a result of which an increase in the accuracy of the algorithm is expected.

Reliability of void detection in structural ceramics using scanning laser acoustic microscopy

NASA Technical Reports Server (NTRS)

Roth, D. J.; Klima, S. J.; Kiser, J. D.; Baaklini, G. Y.

1985-01-01

The reliability of scanning laser acoustic microscopy (SLAM) for detecting surface voids in structural ceramic test specimens was statistically evaluated. Specimens of sintered silicon nitride and sintered silicon carbide, seeded with surface voids, were examined by SLAM at an ultrasonic frequency of 100 MHz in the as fired condition and after surface polishing. It was observed that polishing substantially increased void detectability. Voids as small as 100 micrometers in diameter were detected in polished specimens with 0.90 probability at a 0.95 confidence level. In addition, inspection times were reduced up to a factor of 10 after polishing. The applicability of the SLAM technique for detection of naturally occurring flaws of similar dimensions to the seeded voids is discussed. A FORTRAN program listing is given for calculating and plotting flaw detection statistics.

A novel visual-inertial monocular SLAM

NASA Astrophysics Data System (ADS)

Yue, Xiaofeng; Zhang, Wenjuan; Xu, Li; Liu, JiangGuo

2018-02-01

With the development of sensors and computer vision research community, cameras, which are accurate, compact, wellunderstood and most importantly cheap and ubiquitous today, have gradually been at the center of robot location. Simultaneous localization and mapping (SLAM) using visual features, which is a system getting motion information from image acquisition equipment and rebuild the structure in unknown environment. We provide an analysis of bioinspired flights in insects, employing a novel technique based on SLAM. Then combining visual and inertial measurements to get high accuracy and robustness. we present a novel tightly-coupled Visual-Inertial Simultaneous Localization and Mapping system which get a new attempt to address two challenges which are the initialization problem and the calibration problem. experimental results and analysis show the proposed approach has a more accurate quantitative simulation of insect navigation, which can reach the positioning accuracy of centimeter level.

Covariance Recovery from a Square Root Information Matrix for Data Association

DTIC Science & Technology

2009-07-02

association is one of the core problems of simultaneous localization and mapping (SLAM), and it requires knowledge about the uncertainties of the...association is one of the core problems of simultaneous localization and mapping (SLAM), and it requires knowledge about the uncertainties of the...back-substitution as well as efficient access to marginal covariances, which is described next. 2.2. Recovering Marginal Covariances Knowledge of the

Severe Psychosis, Drug Dependence, and Hepatitis C Related to Slamming Mephedrone

PubMed Central

Rodríguez-Salgado, Beatriz; Sánchez-Mateos, Daniel

2016-01-01

Background. Synthetic cathinones (SCs), also known as “bath salts,” are β-ketone amphetamine compounds derived from cathinone, a psychoactive substance found in Catha edulis. Mephedrone is the most representative SC. Slamming is the term used for the intravenous injection of these substances in the context of chemsex parties, in order to enhance sex experiences. Using IV mephedrone may lead to diverse medical and psychiatric complications like psychosis, aggressive behavior, and suicide ideation. Case. We report the case of a 25-year-old man admitted into a psychiatric unit, presenting with psychotic symptoms after slamming mephedrone almost every weekend for the last 4 months. He presents paranoid delusions, intense anxiety, and visual and kinesthetic hallucinations. He also shows intense craving, compulsive drug use, general malaise, and weakness. After four weeks of admission and antipsychotic treatment, delusions completely disappear. The patient is reinfected with hepatitis C. Discussion. Psychiatric and medical conditions related to chemsex and slamming have been reported in several European cities, but not in Spain. Psychotic symptoms have been associated with mephedrone and other SCs' consumption, with the IV route being prone to produce more severe symptomatology and addictive conducts. In the case we report, paranoid psychosis, addiction, and medical complications are described. PMID:27247820

Water Impact of Syntactic Foams

PubMed Central

Shams, Adel; Zhao, Sam; Porfiri, Maurizio

2017-01-01

Syntactic foams are particulate composite materials that are extensively integrated in naval and aerospace structures as core materials for sandwich panels. While several studies have demonstrated the potential of syntactic foams as energy absorbing materials in impact tests, our understanding of their response to water impact remains elusive. In this work, we attempt a first characterization of the behavior of a vinyl ester/glass syntactic subject to slamming. High-speed imaging is leveraged to elucidate the physics of water impact of syntactic foam wedges in a free-fall drop tower. From the images, we simultaneously measure the deformation of the wedge and the hydrodynamic loading, thereby clarifying the central role of fluid–structure interaction during water impact. We study two different impact heights and microballoon density to assess the role of impact energy and syntactic foam composition on the slamming response. Our results demonstrate that both these factors have a critical role on the slamming response of syntactic foams. Reducing the density of microballoons might help to reduce the severity of the hydrodynamic loading experienced by the wedge, but this comes at the expense of a larger deformation. Such a larger deformation could ultimately lead to failure for large drop heights. These experimental results offer compelling evidence for the role of hydroelastic coupling in the slamming response of syntactic foams. PMID:28772581

Layout Slam with Model Based Loop Closure for 3d Indoor Corridor Reconstruction

NASA Astrophysics Data System (ADS)

Baligh Jahromi, A.; Sohn, G.; Jung, J.; Shahbazi, M.; Kang, J.

2018-05-01

In this paper, we extend a recently proposed visual Simultaneous Localization and Mapping (SLAM) techniques, known as Layout SLAM, to make it robust against error accumulations, abrupt changes of camera orientation and miss-association of newly visited parts of the scene to the previously visited landmarks. To do so, we present a novel technique of loop closing based on layout model matching; i.e., both model information (topology and geometry of reconstructed models) and image information (photometric features) are used to address a loop-closure detection. The advantages of using the layout-related information in the proposed loop-closing technique are twofold. First, it imposes a metric constraint on the global map consistency and, thus, adjusts the mapping scale drifts. Second, it can reduce matching ambiguity in the context of indoor corridors, where the scene is homogenously textured and extracting sufficient amount of distinguishable point features is a challenging task. To test the impact of the proposed technique on the performance of Layout SLAM, we have performed the experiments on wide-angle videos captured by a handheld camera. This dataset was collected from the indoor corridors of a building at York University. The obtained results demonstrate that the proposed method successfully detects the instances of loops while producing very limited trajectory errors.

Registering Ground and Satellite Imagery for Visual Localization

DTIC Science & Technology

2012-08-01

reckoning, inertial, stereo, light detection and ranging ( LIDAR ), cellular radio, and visual. As no sensor or algorithm provides perfect localization in...by metric localization approaches to confine the region of a map that needs to be searched. Simultaneous Localization and Mapping ( SLAM ) (5, 6), using...estimate the metric location of the camera. Se et al. (7) use SIFT features for both appearance-based global localization and incremental 3D SLAM . Johns and

An Indoor Slam Method Based on Kinect and Multi-Feature Extended Information Filter

NASA Astrophysics Data System (ADS)

Chang, M.; Kang, Z.

2017-09-01

Based on the frame of ORB-SLAM in this paper the transformation parameters between adjacent Kinect image frames are computed using ORB keypoints, from which priori information matrix and information vector are calculated. The motion update of multi-feature extended information filter is then realized. According to the point cloud data formed by depth image, ICP algorithm was used to extract the point features of the point cloud data in the scene and built an observation model while calculating a-posteriori information matrix and information vector, and weakening the influences caused by the error accumulation in the positioning process. Furthermore, this paper applied ORB-SLAM frame to realize autonomous positioning in real time in interior unknown environment. In the end, Lidar was used to get data in the scene in order to estimate positioning accuracy put forward in this paper.

Cooperative Monocular-Based SLAM for Multi-UAV Systems in GPS-Denied Environments †

PubMed Central

Guerra, Edmundo

2018-01-01

This work presents a cooperative monocular-based SLAM approach for multi-UAV systems that can operate in GPS-denied environments. The main contribution of the work is to show that, using visual information obtained from monocular cameras mounted onboard aerial vehicles flying in formation, the observability properties of the whole system are improved. This fact is especially notorious when compared with other related visual SLAM configurations. In order to improve the observability properties, some measurements of the relative distance between the UAVs are included in the system. These relative distances are also obtained from visual information. The proposed approach is theoretically validated by means of a nonlinear observability analysis. Furthermore, an extensive set of computer simulations is presented in order to validate the proposed approach. The numerical simulation results show that the proposed system is able to provide a good position and orientation estimation of the aerial vehicles flying in formation. PMID:29701722

Applying FastSLAM to Articulated Rovers

NASA Astrophysics Data System (ADS)

Hewitt, Robert Alexander

This thesis presents the navigation algorithms designed for use on Kapvik, a 30 kg planetary micro-rover built for the Canadian Space Agency; the simulations used to test the algorithm; and novel techniques for terrain classification using Kapvik's LIDAR (Light Detection And Ranging) sensor. Kapvik implements a six-wheeled, skid-steered, rocker-bogie mobility system. This warrants a more complicated kinematic model for navigation than a typical 4-wheel differential drive system. The design of a 3D navigation algorithm is presented that includes nonlinear Kalman filtering and Simultaneous Localization and Mapping (SLAM). A neural network for terrain classification is used to improve navigation performance. Simulation is used to train the neural network and validate the navigation algorithms. Real world tests of the terrain classification algorithm validate the use of simulation for training and the improvement to SLAM through the reduction of extraneous LIDAR measurements in each scan.

Cooperative Monocular-Based SLAM for Multi-UAV Systems in GPS-Denied Environments.

PubMed

Trujillo, Juan-Carlos; Munguia, Rodrigo; Guerra, Edmundo; Grau, Antoni

2018-04-26

This work presents a cooperative monocular-based SLAM approach for multi-UAV systems that can operate in GPS-denied environments. The main contribution of the work is to show that, using visual information obtained from monocular cameras mounted onboard aerial vehicles flying in formation, the observability properties of the whole system are improved. This fact is especially notorious when compared with other related visual SLAM configurations. In order to improve the observability properties, some measurements of the relative distance between the UAVs are included in the system. These relative distances are also obtained from visual information. The proposed approach is theoretically validated by means of a nonlinear observability analysis. Furthermore, an extensive set of computer simulations is presented in order to validate the proposed approach. The numerical simulation results show that the proposed system is able to provide a good position and orientation estimation of the aerial vehicles flying in formation.

Electron acceleration to high energies at quasi-parallel shock waves in the solar corona

NASA Technical Reports Server (NTRS)

Mann, G.; Classen, H.-T.

1995-01-01

In the solar corona shock waves are generated by flares and/or coronal mass ejections. They manifest themselves in solar type 2 radio bursts appearing as emission stripes with a slow drift from high to low frequencies in dynamic radio spectra. Their nonthermal radio emission indicates that electrons are accelerated to suprathermal and/or relativistic velocities at these shocks. As well known by extraterrestrial in-situ measurements supercritical, quasi-parallel, collisionless shocks are accompanied by so-called SLAMS (short large amplitude magnetic field structures). These SLAMS can act as strong magnetic mirrors, at which charged particles can be reflected and accelerated. Thus, thermal electrons gain energy due to multiple reflections between two SLAMS and reach suprathermal and relativistic velocities. This mechanism of accelerating electrons is discussed for circumstances in the solar corona and may be responsible for the so-called 'herringbones' observed in solar type 2 radio bursts.

Reticulocytes bearing C4d as biomarkers of disease activity for systemic lupus erythematosus.

PubMed

Liu, Chau-Ching; Manzi, Susan; Kao, Amy H; Navratil, Jeannine S; Ruffing, Margie J; Ahearn, Joseph M

2005-10-01

There is an urgent need for biomarkers with which to monitor disease activity in patients with systemic lupus erythematosus (SLE). We recently showed that abnormal levels of C4d, an activation-derived fragment of complement component C4, are deposited on the surface of erythrocytes from patients with SLE. This study focused on reticulocytes, the youngest and shortest-lived erythrocytes (lifespan 24-48 hours), with the objective of testing our hypothesis that when reticulocytes emerge from the bone marrow, they are immediately exposed to and acquire C4d at levels proportionate to the extent of complement activation at that time, thereby reflecting disease activity in SLE. We conducted a cross-sectional study of 156 patients with SLE, 140 patients with other diseases, and 159 healthy controls. Levels of C4d on the surface of reticulocytes were examined using a 2-color flow cytometric assay. The results were analyzed for correlations with SLE disease activity. A wide range of increased levels of reticulocyte C4d was specifically detected in SLE patients. These levels fluctuated in SLE patients and correlated with clinical disease activity, as determined by the Safety of Estrogens in Lupus Erythematosus: National Assessment (SELENA) version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the Systemic Lupus Activity Measure (SLAM). Specifically, in cross-sectional analyses, patients with reticulocyte C4d levels in the highest quartile compared with those in the lowest quartile had significantly higher SELENA-SLEDAI (P = 0.00002) and SLAM (P = 0.02) scores. Longitudinal observation demonstrated that the reticulocyte C4d levels changed in relation to the clinical course in individual patients. These findings support our hypothesis that C4d-bearing reticulocytes may serve as biomarkers of disease activity in patients with SLE.

Data on the effect of oral feeding of Arachidonic acid or Docosahexanoic acid on haematopoiesis in mice.

PubMed

Limbkar, Kedar; Dhenge, Ankita; Jadhav, Dipesh D; Thulasiram, Hirekodathakallu V; Kale, Vaijayanti; Limaye, Lalita

2017-10-01

Stem cells have peculiar property to self-renew and differentiate. It is important to control their fate in safe and effective ways for their therapeutic use. The mediators of essential polyunsaturated fatty acids (PUFAs) namely Arachidonic acid (AA) and Docosahexanoic acid (DHA) are known to play a role in haematopoiesis via various metabolic pathways [1]. However the direct effect of purified AA or DHA on haematopoiesis has not been well investigated yet. We have reported that oral administration of PUFAs enhanced haematopoiesis in mice [2]. Signaling Leukocyte Antigen Molecule (SLAM) (CD48 - CD150 + ) phenotype consists of pure population of haematopoietic stem cells (HSCs). Herein we observed higher percentage of SLAM (CD48 - CD150 + ) phenotype in the bone marrow (BM) cells of mice fed with AA or DHA compared to PBS fed control mice. Data from engraftment study depicts that BM from AA/DHA-fed mice showed higher absolute number of donor cells in recipient mice compared to control. The enhanced hematopoiesis observed in AA/DHA-fed mice was returned to normal when the mice were kept on normal diet for six weeks (after ten days of oral feeding). We confirmed GCMS (Gas Chromatography-Mass Spectroscopy) retention times of AA and DHA by co-injecting fatty acid extract from AA or DHA fed mice with purified AA or DHA standards respectively. Representative flow cytometry profile of Lin - Sca-1 + c-kit + (LSK) cells showed higher expression of CXCR4 protein and ligands of Wnt, Notch1 signaling in BM of AA/DHA-fed mice.

2006 Precision Strike Technology Symposium

DTIC Science & Technology

2006-10-19

s Navy Unique Joint system 14 A/C Unique Components Framework JMPS Common Components Crypto Key GCCS-M Interface Carrier Intel Feed Carrier...210 GPS Prediction CUPC GPS Crypto Key TAMMAC SLAM-ER GPS Almanac ETIRMS PMA-281 NGMS PMA-209 Boeing PMA-201 Raytheon ESC (USAF) Hill AFB PMA-234 PMA...242 F/A-18 UPC GPS Prediction CUPC GPS Crypto Key TAMMAC SLAM-ER GPS Almanac HARM WASP Framework ARC-210 ETIRMS PMA-281 Integration/Test/ Support TLAM

Solution to the SLAM problem in low dynamic environments using a pose graph and an RGB-D sensor.

PubMed

Lee, Donghwa; Myung, Hyun

2014-07-11

In this study, we propose a solution to the simultaneous localization and mapping (SLAM) problem in low dynamic environments by using a pose graph and an RGB-D (red-green-blue depth) sensor. The low dynamic environments refer to situations in which the positions of objects change over long intervals. Therefore, in the low dynamic environments, robots have difficulty recognizing the repositioning of objects unlike in highly dynamic environments in which relatively fast-moving objects can be detected using a variety of moving object detection algorithms. The changes in the environments then cause groups of false loop closing when the same moved objects are observed for a while, which means that conventional SLAM algorithms produce incorrect results. To address this problem, we propose a novel SLAM method that handles low dynamic environments. The proposed method uses a pose graph structure and an RGB-D sensor. First, to prune the falsely grouped constraints efficiently, nodes of the graph, that represent robot poses, are grouped according to the grouping rules with noise covariances. Next, false constraints of the pose graph are pruned according to an error metric based on the grouped nodes. The pose graph structure is reoptimized after eliminating the false information, and the corrected localization and mapping results are obtained. The performance of the method was validated in real experiments using a mobile robot system.

SLAM family member 8 is involved in oncogenic KIT-mediated signaling in human mastocytosis.

PubMed

Sugimoto, Akihiko; Kataoka, Tatsuki R; Ueshima, Chiyuki; Takei, Yusuke; Kitamura, Kyohei; Hirata, Masahiro; Nomura, Takashi; Haga, Hironori

2018-03-02

The signaling lymphocytic activation molecule family member 8 (SLAMF8)/CD353 is a member of the CD2 family of proteins. Its ligand has not been identified. SLAMF8 is expressed by macrophages and suppresses cellular functions. No study has yet explored SLAMF8 expression or function in human mastocytosis, which features oncogenic KIT-mediated proliferation of human mast cells. SLAMF8 protein was expressed in human mastocytosis cells, immunohistochemically. SLAMF8 expression was also evident in the human mast cell lines, HMC1.2 (expressing oncogenic KIT) and LAD2 (expressing wild-type KIT) cells. SLAMF8-knockdown significantly reduced the KIT-mediated growth of HMC1.2 cells but not that of LAD2 cells. SLAMF8-knockdown HMC1.2 cells exhibited significant attenuation of SHP-2 activation and oncogenic KIT-mediated RAS-RAF-ERK signaling. An interaction between SLAMF8 and SHP-2 was confirmed in HMC1.2 cells and all pathological mastocytosis specimens examined (19 of 19 cases, 100%). Thus, SLAMF8 is involved in oncogenic KIT-mediated RAS-RAF-ERK signaling and the subsequent growth of human neoplastic mast cells mediated by SHP-2. SLAMF8 is a possible therapeutic target in human mastocytosis patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The Improved Locating Algorithm of Particle Filter Based on ROS Robot

NASA Astrophysics Data System (ADS)

Fang, Xun; Fu, Xiaoyang; Sun, Ming

2018-03-01

This paperanalyzes basic theory and primary algorithm of the real-time locating system and SLAM technology based on ROS system Robot. It proposes improved locating algorithm of particle filter effectively reduces the matching time of laser radar and map, additional ultra-wideband technology directly accelerates the global efficiency of FastSLAM algorithm, which no longer needs searching on the global map. Meanwhile, the re-sampling has been largely reduced about 5/6 that directly cancels the matching behavior on Roboticsalgorithm.

A SLAM II simulation model for analyzing space station mission processing requirements

NASA Technical Reports Server (NTRS)

Linton, D. G.

1985-01-01

Space station mission processing is modeled via the SLAM 2 simulation language on an IBM 4381 mainframe and an IBM PC microcomputer with 620K RAM, two double-sided disk drives and an 8087 coprocessor chip. Using a time phased mission (payload) schedule and parameters associated with the mission, orbiter (space shuttle) and ground facility databases, estimates for ground facility utilization are computed. Simulation output associated with the science and applications database is used to assess alternative mission schedules.

NASA Sees Winter Storm Slamming Eastern United States

NASA Image and Video Library

2017-12-08

NASA satellite imagery captured the size of the massive winter storm that continued to pummel the U.S. East Coast early on January 23, 2016. This visible image of the major winter storm was taken from NOAA's GOES-East satellite on Saturday, January 23, 2016 at 1437 UTC (9:37 a.m. EST) as the Baltimore/Washington corridor was under a blizzard warning. Read more: go.nasa.gov/1RFv70u Credits: NASA/NOAA GOES Project NASA Sees Winter Storm Slamming Eastern United States

Team VaCAS Design and Development of Cooperative UGV System

DTIC Science & Technology

2011-02-04

Mapping ( SLAM ) [24]. Similar to such work, the technique to be used in the project will also (1) use the last reliably available data as the reference...Losada1, D., Matia1, F., Pedraza1, L., Jimenez A. and Galan, R., Consistency of SLAM -EKF Algorithms for Indoor Environments, Journal of Intelligent and...mounted on the UGV 1 include GPS for outdoor navigation, LiDAR for obstacle avoidance and mapping and camera for OOI detection and localization. UGVs 2

A Simple Hierarchical Pooling Data Structure for Loop Closure

DTIC Science & Technology

2016-10-16

ticated agglomerative schemes at a fraction of the effort. 1.1 Related work Loop closure is a key component in robotic mapping (SLAM) [37], autonomous...appearance-only slam-fab-map 2.0. In: Robotics : Science and Systems. vol. 5. Seattle, USA (2009) 7. Dong, J., Soatto, S.: Domain size pooling in local...detection with bags of binary words. In: Intelligent Robots and Systems (IROS), 2011 IEEE/RSJ Intl. Conf. on. pp. 51–58. IEEE (2011) 9. Geiger, A

SLAM-seq defines direct gene-regulatory functions of the BRD4-MYC axis.

PubMed

Muhar, Matthias; Ebert, Anja; Neumann, Tobias; Umkehrer, Christian; Jude, Julian; Wieshofer, Corinna; Rescheneder, Philipp; Lipp, Jesse J; Herzog, Veronika A; Reichholf, Brian; Cisneros, David A; Hoffmann, Thomas; Schlapansky, Moritz F; Bhat, Pooja; von Haeseler, Arndt; Köcher, Thomas; Obenauf, Anna C; Popow, Johannes; Ameres, Stefan L; Zuber, Johannes

2018-05-18

Defining direct targets of transcription factors and regulatory pathways is key to understanding their roles in physiology and disease. We combined SLAM-seq [thiol(SH)-linked alkylation for the metabolic sequencing of RNA], a method for direct quantification of newly synthesized messenger RNAs (mRNAs), with pharmacological and chemical-genetic perturbation in order to define regulatory functions of two transcriptional hubs in cancer, BRD4 and MYC, and to interrogate direct responses to BET bromodomain inhibitors (BETis). We found that BRD4 acts as general coactivator of RNA polymerase II-dependent transcription, which is broadly repressed upon high-dose BETi treatment. At doses triggering selective effects in leukemia, BETis deregulate a small set of hypersensitive targets including MYC. In contrast to BRD4, MYC primarily acts as a selective transcriptional activator controlling metabolic processes such as ribosome biogenesis and de novo purine synthesis. Our study establishes a simple and scalable strategy to identify direct transcriptional targets of any gene or pathway. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Systemic lupus erythematosus in a multiethnic U.S. cohort (LUMINA) XXVII: factors predictive of a decline to low levels of disease activity.

PubMed

Bertoli, A M; Alarcón, G S; McGwin, G; Fernández, M; Bastian, H M; Fessler, B J; Vilá, L M; Reveille, J D

2006-01-01

The objective of this study was to examine factors predictive of a decline to low levels of disease activity in a cohort of systemic lupus erythematosus (SLE) patients. Patients with SLE of Hispanic (from Texas or Puerto Rico), African-American or Caucasian ethnicity from a multiethnic cohort were included. A decline to low levels of disease activity was defined as a score < or =5 as per the Systemic Lupus Activity Measure-Revised (SLAM-R) at any annual study visit if preceded by a SLAM-R > or =8. Using Generalized Estimating Equation (GEE), socioeconomic-demographic, behavioral, function, psychological, laboratory and clinical data [disease manifestations, number of ACR criteria accrued at diagnosis and damage accrual as per the Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI)] from the visit preceding that meeting the definition were examined as predictors of decline to low levels of disease activity. Two-hundred and eighty-seven patients (67 Hispanics from Texas, 32 Hispanics form Puerto Rico, 120 African-Americans and 68 Caucasians), accounting for 632 visits were analyzed. In the GEE multivariable analysis, higher degrees of social support (OR = 1.208, 95% CI 1.059-1.379; P = 0.005) were predictive of a decline to low levels of disease activity, while the number of ACR criteria accrued at diagnosis (OR = 0.765, 95% CI 0.631-0.927; P = 0.006) and damage (OR = 0.850, 95% CI 0.743-0.972, P = 0.018) were negatively associated. These data suggest that a decline to low levels of disease activity in lupus patients seems to be multifactorial; this study also underscores the importance of social support for lupus patients.

Validation of Underwater Sensor Package Using Feature Based SLAM

PubMed Central

Cain, Christopher; Leonessa, Alexander

2016-01-01

Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package. PMID:26999142

Active Visual SLAM with Exploration for Autonomous Underwater Navigation

DTIC Science & Technology

2012-01-01

tourism. Reconstruction of Notre Dame de Paris (Snavely et al., 2006). (c) Web-scale landmark recognition engine (Zheng et al., 2009). eters for an...structures, such as Notre Dame Cathedral in Paris and the Great Wall of China (Figure 1.3(b)), using photographs compiled from the Internet. Given the...representation. Originally developed for text-based applications, expansion of this approach to images were found in Leung and Malik (2001), Sivic and Zisserman

Sources of nitrogen and phosphorus emissions to Irish rivers: estimates from the Source Load Apportionment Model (SLAM)

NASA Astrophysics Data System (ADS)

Mockler, Eva; Deakin, Jenny; Archbold, Marie; Daly, Donal; Bruen, Michael

2017-04-01

More than half of the river and lake water bodies in Europe are at less than good ecological status or potential, and diffuse pollution from agriculture remains a major, but not the only, cause of this poor performance. In Ireland, it is evident that agri-environmental policy and land management practices have, in many areas, reduced nutrient emissions to water, mitigating the potential impact on water quality. However, additional measures may be required in order to further decouple the relationship between agricultural productivity and emissions to water, which is of vital importance given the on-going agricultural intensification in Ireland. Catchment management can be greatly supported by modelling, which can reduce the resources required to analyse large amounts of information and can enable investigations and measures to be targeted. The Source Load Apportionment Model (SLAM) framework was developed to support catchment management in Ireland by characterising the contributions from various sources of phosphorus (P) and nitrogen (N) emissions to water. The SLAM integrates multiple national spatial datasets relating to nutrient emissions to surface water, including land use and physical characteristics of the sub-catchments to predict emissions from point (wastewater, industry discharges and septic tank systems) and diffuse sources (agriculture, forestry, peatlands, etc.). The annual nutrient emissions predicted by the SLAM were assessed against nutrient monitoring data for 16 major river catchments covering 50% of the area of Ireland. At national scale, results indicate that the total average annual emissions to surface water in Ireland are over 2,700 t yr-1 of P and 80,000 t yr-1 of N. The SLAM results include the proportional contributions from individual sources at a range of scales from sub-catchment to national, and show that the main sources of P are from wastewater and agriculture, with wide variations across the country related to local anthropogenic pressures and the hydrogeological setting. Agriculture is the main source of N emissions to water across all regions of Ireland. The SLAM results have been incorporated into an Integrated Catchment Management process and used in conjunction with monitoring data and local knowledge during the characterisation of all Irish water bodies by the Environmental Protection Agency. This demonstrates the successful integration of research into catchment management to inform the identification of (i) the sources of nutrients at regional and local scales and (ii) the potential significant pressures and appropriate mitigation measures.

LERC-SLAM - THE NASA LEWIS RESEARCH CENTER SATELLITE LINK ATTENUATION MODEL PROGRAM (MACINTOSH VERSION)

NASA Technical Reports Server (NTRS)

Manning, R. M.

1994-01-01

The frequency and intensity of rain attenuation affecting the communication between a satellite and an earth terminal is an important consideration in planning satellite links. The NASA Lewis Research Center Satellite Link Attenuation Model Program (LeRC-SLAM) provides a static and dynamic statistical assessment of the impact of rain attenuation on a communications link established between an earth terminal and a geosynchronous satellite. The program is designed for use in the specification, design and assessment of satellite links for any terminal location in the continental United States. The basis for LeRC-SLAM is the ACTS Rain Attenuation Prediction Model, which uses a log-normal cumulative probability distribution to describe the random process of rain attenuation on satellite links. The derivation of the statistics for the rainrate process at the specified terminal location relies on long term rainfall records compiled by the U.S. Weather Service during time periods of up to 55 years in length. The theory of extreme value statistics is also utilized. The user provides 1) the longitudinal position of the satellite in geosynchronous orbit, 2) the geographical position of the earth terminal in terms of latitude and longitude, 3) the height above sea level of the terminal site, 4) the yearly average rainfall at the terminal site, and 5) the operating frequency of the communications link (within 1 to 1000 GHz, inclusive). Based on the yearly average rainfall at the terminal location, LeRC-SLAM calculates the relevant rain statistics for the site using an internal data base. The program then generates rain attenuation data for the satellite link. This data includes a description of the static (i.e., yearly) attenuation process, an evaluation of the cumulative probability distribution for attenuation effects, and an evaluation of the probability of fades below selected fade depths. In addition, LeRC-SLAM calculates the elevation and azimuth angles of the terminal antenna required to establish a link with the satellite, the statistical parameters that characterize the rainrate process at the terminal site, the length of the propagation path within the potential rain region, and its projected length onto the local horizontal. The IBM PC version of LeRC-SLAM (LEW-14979) is written in Microsoft QuickBASIC for an IBM PC compatible computer with a monitor and printer capable of supporting an 80-column format. The IBM PC version is available on a 5.25 inch MS-DOS format diskette. The program requires about 30K RAM. The source code and executable are included. The Macintosh version of LeRC-SLAM (LEW-14977) is written in Microsoft Basic, Binary (b) v2.00 for Macintosh II series computers running MacOS. This version requires 400K RAM and is available on a 3.5 inch 800K Macintosh format diskette, which includes source code only. The Macintosh version was developed in 1987 and the IBM PC version was developed in 1989. IBM PC is a trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

LERC-SLAM - THE NASA LEWIS RESEARCH CENTER SATELLITE LINK ATTENUATION MODEL PROGRAM (IBM PC VERSION)

NASA Technical Reports Server (NTRS)

Manning, R. M.

1994-01-01

The frequency and intensity of rain attenuation affecting the communication between a satellite and an earth terminal is an important consideration in planning satellite links. The NASA Lewis Research Center Satellite Link Attenuation Model Program (LeRC-SLAM) provides a static and dynamic statistical assessment of the impact of rain attenuation on a communications link established between an earth terminal and a geosynchronous satellite. The program is designed for use in the specification, design and assessment of satellite links for any terminal location in the continental United States. The basis for LeRC-SLAM is the ACTS Rain Attenuation Prediction Model, which uses a log-normal cumulative probability distribution to describe the random process of rain attenuation on satellite links. The derivation of the statistics for the rainrate process at the specified terminal location relies on long term rainfall records compiled by the U.S. Weather Service during time periods of up to 55 years in length. The theory of extreme value statistics is also utilized. The user provides 1) the longitudinal position of the satellite in geosynchronous orbit, 2) the geographical position of the earth terminal in terms of latitude and longitude, 3) the height above sea level of the terminal site, 4) the yearly average rainfall at the terminal site, and 5) the operating frequency of the communications link (within 1 to 1000 GHz, inclusive). Based on the yearly average rainfall at the terminal location, LeRC-SLAM calculates the relevant rain statistics for the site using an internal data base. The program then generates rain attenuation data for the satellite link. This data includes a description of the static (i.e., yearly) attenuation process, an evaluation of the cumulative probability distribution for attenuation effects, and an evaluation of the probability of fades below selected fade depths. In addition, LeRC-SLAM calculates the elevation and azimuth angles of the terminal antenna required to establish a link with the satellite, the statistical parameters that characterize the rainrate process at the terminal site, the length of the propagation path within the potential rain region, and its projected length onto the local horizontal. The IBM PC version of LeRC-SLAM (LEW-14979) is written in Microsoft QuickBASIC for an IBM PC compatible computer with a monitor and printer capable of supporting an 80-column format. The IBM PC version is available on a 5.25 inch MS-DOS format diskette. The program requires about 30K RAM. The source code and executable are included. The Macintosh version of LeRC-SLAM (LEW-14977) is written in Microsoft Basic, Binary (b) v2.00 for Macintosh II series computers running MacOS. This version requires 400K RAM and is available on a 3.5 inch 800K Macintosh format diskette, which includes source code only. The Macintosh version was developed in 1987 and the IBM PC version was developed in 1989. IBM PC is a trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

Using biomedical engineering and "hidden capital" to provide educational outreach to disadvantaged populations.

PubMed

Drazan, John F; Scott, John M; Hoke, Jahkeen I; Ledet, Eric H

2014-01-01

A hands-on learning module called "Science of the Slam" is created that taps into the passions and interests of an under-represented group in the fields of Science, Technology, Engineering and Mathematics (STEM). This is achieved by examining the use of the scientific method to quantify the biomechanics of basketball players who are good at performing the slam dunk. Students already have an intrinsic understanding of the biomechanics of basketball however this "hidden capital" has never translated into the underlying STEM concepts. The effectiveness of the program is rooted in the exploitation of "hidden capital" within the field of athletics to inform and enhance athletic performance. This translation of STEM concepts to athletic performance provides a context and a motivation for students to study the STEM fields who are traditionally disengaged from the classic engineering outreach programs. "Science of the Slam" has the potential to serve as a framework for other researchers to engage under-represented groups in novel ways by tapping into shared interests between the researcher and disadvantaged populations.

Learning Probabilistic Features for Robotic Navigation Using Laser Sensors

PubMed Central

Aznar, Fidel; Pujol, Francisco A.; Pujol, Mar; Rizo, Ramón; Pujol, María-José

2014-01-01

SLAM is a popular task used by robots and autonomous vehicles to build a map of an unknown environment and, at the same time, to determine their location within the map. This paper describes a SLAM-based, probabilistic robotic system able to learn the essential features of different parts of its environment. Some previous SLAM implementations had computational complexities ranging from O(Nlog(N)) to O(N 2), where N is the number of map features. Unlike these methods, our approach reduces the computational complexity to O(N) by using a model to fuse the information from the sensors after applying the Bayesian paradigm. Once the training process is completed, the robot identifies and locates those areas that potentially match the sections that have been previously learned. After the training, the robot navigates and extracts a three-dimensional map of the environment using a single laser sensor. Thus, it perceives different sections of its world. In addition, in order to make our system able to be used in a low-cost robot, low-complexity algorithms that can be easily implemented on embedded processors or microcontrollers are used. PMID:25415377

Learning probabilistic features for robotic navigation using laser sensors.

PubMed

Aznar, Fidel; Pujol, Francisco A; Pujol, Mar; Rizo, Ramón; Pujol, María-José

2014-01-01

SLAM is a popular task used by robots and autonomous vehicles to build a map of an unknown environment and, at the same time, to determine their location within the map. This paper describes a SLAM-based, probabilistic robotic system able to learn the essential features of different parts of its environment. Some previous SLAM implementations had computational complexities ranging from O(Nlog(N)) to O(N(2)), where N is the number of map features. Unlike these methods, our approach reduces the computational complexity to O(N) by using a model to fuse the information from the sensors after applying the Bayesian paradigm. Once the training process is completed, the robot identifies and locates those areas that potentially match the sections that have been previously learned. After the training, the robot navigates and extracts a three-dimensional map of the environment using a single laser sensor. Thus, it perceives different sections of its world. In addition, in order to make our system able to be used in a low-cost robot, low-complexity algorithms that can be easily implemented on embedded processors or microcontrollers are used.

RGB-D SLAM Based on Extended Bundle Adjustment with 2D and 3D Information

PubMed Central

Di, Kaichang; Zhao, Qiang; Wan, Wenhui; Wang, Yexin; Gao, Yunjun

2016-01-01

In the study of SLAM problem using an RGB-D camera, depth information and visual information as two types of primary measurement data are rarely tightly coupled during refinement of camera pose estimation. In this paper, a new method of RGB-D camera SLAM is proposed based on extended bundle adjustment with integrated 2D and 3D information on the basis of a new projection model. First, the geometric relationship between the image plane coordinates and the depth values is constructed through RGB-D camera calibration. Then, 2D and 3D feature points are automatically extracted and matched between consecutive frames to build a continuous image network. Finally, extended bundle adjustment based on the new projection model, which takes both image and depth measurements into consideration, is applied to the image network for high-precision pose estimation. Field experiments show that the proposed method has a notably better performance than the traditional method, and the experimental results demonstrate the effectiveness of the proposed method in improving localization accuracy. PMID:27529256

Reliability of scanning laser acoustic microscopy for detecting internal voids in structural ceramics

NASA Technical Reports Server (NTRS)

Roth, D. J.; Baaklini, G. Y.

1986-01-01

The reliability of 100 MHz scanning laser acoustic microscopy (SLAM) for detecting internal voids in sintered specimens of silicon nitride and silicon carbide was evaluated. The specimens contained artificially implanted voids and were positioned at depths ranging up to 2 mm below the specimen surface. Detection probability of 0.90 at a 0.95 confidence level was determined as a function of material, void diameter, and void depth. The statistical results presented for void detectability indicate some of the strengths and limitations of SLAM as a nondestructive evaluation technique for structural ceramics.

System analysis for the Huntsville Operational Support Center distributed computer system

NASA Technical Reports Server (NTRS)

Ingels, E. M.

1983-01-01

A simulation model was developed and programmed in three languages BASIC, PASCAL, and SLAM. Two of the programs are included in this report, the BASIC and the PASCAL language programs. SLAM is not supported by NASA/MSFC facilities and hence was not included. The statistical comparison of simulations of the same HOSC system configurations are in good agreement and are in agreement with the operational statistics of HOSC that were obtained. Three variations of the most recent HOSC configuration was run and some conclusions drawn as to the system performance under these variations.

Functional role of human NK cell receptor 2B4 (CD244) isoforms.

PubMed

Mathew, Stephen O; Rao, Krithi K; Kim, Jong R; Bambard, Nowland D; Mathew, Porunelloor A

2009-06-01

2B4 (CD244), a member of the signaling lymphocyte-activation molecule (SLAM/CD150), is expressed on all NK cells, a subpopulation of T cells, monocytes and basophils. Human NK cells express two isoforms of 2B4, h2B4-A and h2B4-B that differ in a small portion of the extracellular domain. In the present investigation, we have studied the functions of h2B4-A and h2B4-B. Our study demonstrated that these two isoforms differ in their binding affinity for CD48, which results in differential cytotoxic activity as well as intracellular calcium release by NK cells upon target cell recognition. Analysis of the predicted 3-D structure of the two isoforms showed conformational differences that could account for their differences in binding affinity to CD48. h2B4-A was able to mediate natural cytotoxicity against CD48-expressing K562 target cells and induce intracellular calcium release, whereas h2B4-B showed no effects. NK-92MI, U937, THP-1, KU812, primary monocytes, basophils and NK cells showed expression of both h2B4-A and h2B4-B whereas YT and IL-2-activated NK cells did not show any h2B4-B expression. Stimulation of NK cells through 2B4 resulted in decreased mRNA levels of both h2B4-A and h2B4-B indicating that down-regulation of 2B4 isoforms may be an important factor in controlling NK cell activation during immune responses.

Predictors of post-partum damage accrual in systemic lupus erythematosus: data from LUMINA, a multiethnic US cohort (XXXVIII).

PubMed

Andrade, R M; McGwin, G; Alarcón, G S; Sanchez, M L; Bertoli, A M; Fernández, M; Fessler, B J; Apte, M; Arango, A M; Bastian, H M; Vilá, L M; Reveille, J D

2006-11-01

To determine the impact of pregnancy on systemic lupus erythematosus (SLE) outcome. SLE patients, age >or=16 yrs, disease duration

Multibeam 3D Underwater SLAM with Probabilistic Registration.

PubMed

Palomer, Albert; Ridao, Pere; Ribas, David

2016-04-20

This paper describes a pose-based underwater 3D Simultaneous Localization and Mapping (SLAM) using a multibeam echosounder to produce high consistency underwater maps. The proposed algorithm compounds swath profiles of the seafloor with dead reckoning localization to build surface patches (i.e., point clouds). An Iterative Closest Point (ICP) with a probabilistic implementation is then used to register the point clouds, taking into account their uncertainties. The registration process is divided in two steps: (1) point-to-point association for coarse registration and (2) point-to-plane association for fine registration. The point clouds of the surfaces to be registered are sub-sampled in order to decrease both the computation time and also the potential of falling into local minima during the registration. In addition, a heuristic is used to decrease the complexity of the association step of the ICP from O(n2) to O(n) . The performance of the SLAM framework is tested using two real world datasets: First, a 2.5D bathymetric dataset obtained with the usual down-looking multibeam sonar configuration, and second, a full 3D underwater dataset acquired with a multibeam sonar mounted on a pan and tilt unit.

Camera pose estimation for augmented reality in a small indoor dynamic scene

NASA Astrophysics Data System (ADS)

Frikha, Rawia; Ejbali, Ridha; Zaied, Mourad

2017-09-01

Camera pose estimation remains a challenging task for augmented reality (AR) applications. Simultaneous localization and mapping (SLAM)-based methods are able to estimate the six degrees of freedom camera motion while constructing a map of an unknown environment. However, these methods do not provide any reference for where to insert virtual objects since they do not have any information about scene structure and may fail in cases of occlusion of three-dimensional (3-D) map points or dynamic objects. This paper presents a real-time monocular piece wise planar SLAM method using the planar scene assumption. Using planar structures in the mapping process allows rendering virtual objects in a meaningful way on the one hand and improving the precision of the camera pose and the quality of 3-D reconstruction of the environment by adding constraints on 3-D points and poses in the optimization process on the other hand. We proposed to benefit from the 3-D planes rigidity motion in the tracking process to enhance the system robustness in the case of dynamic scenes. Experimental results show that using a constrained planar scene improves our system accuracy and robustness compared with the classical SLAM systems.

Timestamp Offset Determination Between AN Actuated Laser Scanner and its Corresponding Motor

NASA Astrophysics Data System (ADS)

Voges, R.; Wieghardt, C. S.; Wagner, B.

2017-05-01

Motor actuated 2D laser scanners are key sensors for many robotics applications that need wide ranging but low cost 3D data. There exist many approaches on how to build a 3D laser scanner using this technique, but they often lack proper synchronization for the timestamps of the actuator and the laser scanner. However, to transform the measurement points into three-dimensional space an appropriate synchronization is mandatory. Thus, we propose two different approaches to accomplish the goal of calculating timestamp offsets between laser scanner and motor prior to and after data acquisition. Both approaches use parts of a SLAM algorithm but apply different criteria to find an appropriate solution. While the approach for offset calculation prior to data acquisition exploits the fact that the SLAM algorithm should not register motion for a stationary system, the approach for offset calculation after data acquisition evaluates the perceived clarity of a point cloud created by the SLAM algorithm. Our experiments show that both approaches yield the same results although operating independently on different data, which demonstrates that the results reflect reality with a high probability. Furthermore, our experiments exhibit the significance of a proper synchronization between laser scanner and actuator.

Generation of RGB-D data for SLAM using robotic framework V-REP

NASA Astrophysics Data System (ADS)

Gritsenko, Pavel S.; Gritsenko, Igor S.; Seidakhmet, Askar Zh.; Abduraimov, Azizbek E.

2017-09-01

In this article, we will present a methodology to debug RGB-D SLAM systems as well as to generate testing data. We have created a model of a laboratory with an area of 250 m2 (25 × 10) with set of objects of different type. V-REP Microsoft Kinect sensor simulation model was used as a basis for robot vision system. Motion path of the sensor model has multiple loops. We have written a program in V-Rep native language Lua to record data array from the Microsoft Kinect sensor model. The array includes both RGB and Depth streams with full resolution (640 × 480) for every 10 cm of the path. The simulated path has absolute accuracy, since it is a simulation, and is represented by an array of transformation matrices (4 × 4). The length of the data array is 1000 steps or 100 m. The path simulates frequently occurring cases in SLAM, including loops. It is worth noting that the path was modeled for a mobile robot and it is represented by a 2D path parallel to the floor at a height of 40 cm.

Application of real-time single camera SLAM technology for image-guided targeting in neurosurgery

NASA Astrophysics Data System (ADS)

Chang, Yau-Zen; Hou, Jung-Fu; Tsao, Yi Hsiang; Lee, Shih-Tseng

2012-10-01

In this paper, we propose an application of augmented reality technology for targeting tumors or anatomical structures inside the skull. The application is a combination of the technologies of MonoSLAM (Single Camera Simultaneous Localization and Mapping) and computer graphics. A stereo vision system is developed to construct geometric data of human face for registration with CT images. Reliability and accuracy of the application is enhanced by the use of fiduciary markers fixed to the skull. The MonoSLAM keeps track of the current location of the camera with respect to an augmented reality (AR) marker using the extended Kalman filter. The fiduciary markers provide reference when the AR marker is invisible to the camera. Relationship between the markers on the face and the augmented reality marker is obtained by a registration procedure by the stereo vision system and is updated on-line. A commercially available Android based tablet PC equipped with a 320×240 front-facing camera was used for implementation. The system is able to provide a live view of the patient overlaid by the solid models of tumors or anatomical structures, as well as the missing part of the tool inside the skull.

A robotic orbital emulator with lidar-based SLAM and AMCL for multiple entity pose estimation

NASA Astrophysics Data System (ADS)

Shen, Dan; Xiang, Xingyu; Jia, Bin; Wang, Zhonghai; Chen, Genshe; Blasch, Erik; Pham, Khanh

2018-05-01

This paper revises and evaluates an orbital emulator (OE) for space situational awareness (SSA). The OE can produce 3D satellite movements using capabilities generated from omni-wheeled robot and robotic arm motions. The 3D motion of satellite is partitioned into the movements in the equatorial plane and the up-down motions in the vertical plane. The 3D actions are emulated by omni-wheeled robot models while the up-down motions are performed by a stepped-motorcontrolled- ball along a rod (robotic arm), which is attached to the robot. Lidar only measurements are used to estimate the pose information of the multiple robots. SLAM (simultaneous localization and mapping) is running on one robot to generate the map and compute the pose for the robot. Based on the SLAM map maintained by the robot, the other robots run the adaptive Monte Carlo localization (AMCL) method to estimate their poses. The controller is designed to guide the robot to follow a given orbit. The controllability is analyzed by using a feedback linearization method. Experiments are conducted to show the convergence of AMCL and the orbit tracking performance.

a Mapping Method of Slam Based on Look up Table

NASA Astrophysics Data System (ADS)

Wang, Z.; Li, J.; Wang, A.; Wang, J.

2017-09-01

In the last years several V-SLAM(Visual Simultaneous Localization and Mapping) approaches have appeared showing impressive reconstructions of the world. However these maps are built with far more than the required information. This limitation comes from the whole process of each key-frame. In this paper we present for the first time a mapping method based on the LOOK UP TABLE(LUT) for visual SLAM that can improve the mapping effectively. As this method relies on extracting features in each cell divided from image, it can get the pose of camera that is more representative of the whole key-frame. The tracking direction of key-frames is obtained by counting the number of parallax directions of feature points. LUT stored all mapping needs the number of cell corresponding to the tracking direction which can reduce the redundant information in the key-frame, and is more efficient to mapping. The result shows that a better map with less noise is build using less than one-third of the time. We believe that the capacity of LUT efficiently building maps makes it a good choice for the community to investigate in the scene reconstruction problems.

Domestic dog origin of canine distemper virus in free-ranging wolves in Portugal as revealed by hemagglutinin gene characterization.

PubMed

Müller, Alexandra; Silva, Eliane; Santos, Nuno; Thompson, Gertrude

2011-07-01

Serologic evidence for canine distemper virus (CDV) has been described in grey wolves but, to our knowledge, virus strains circulating in wolves have not been characterized genetically. The emergence of CDV in several non-dog hosts has been associated with amino acid substitutions at sites 530 and 549 of the hemagglutinin (H) protein. We sequenced the H gene of wild-type canine distemper virus obtained from two free-ranging Iberian wolves (Canis lupus signatus) and from one domestic dog (Canis familiaris). More differences were found between the two wolf sequences than between one of the wolves (wolf 75) and the dog. The latter two had a very high nucleotide similarity resulting in identical H gene amino acid sequences. Possible explanations include geographic and especially temporal proximity of the CDV obtained from wolf 75 and the domestic dog, taken in 2007-2008, as opposed to that from wolf 3 taken more distantly in 1998. Analysis of the deduced amino acids of the viral hemagglutinin revealed a glycine (G) and a tyrosine (Y) at amino acid positions 530 and 549, respectively, of the partial signaling lymphocytic activation molecule (SLAM)-receptor binding region which is typically found in viral strains obtained from domestic dogs. This suggests that the CDV found in these wolves resulted from transmission events from local domestic dogs rather than from wildlife species.

Integrated multi-sensor fusion for mapping and localization in outdoor environments for mobile robots

NASA Astrophysics Data System (ADS)

Emter, Thomas; Petereit, Janko

2014-05-01

An integrated multi-sensor fusion framework for localization and mapping for autonomous navigation in unstructured outdoor environments based on extended Kalman filters (EKF) is presented. The sensors for localization include an inertial measurement unit, a GPS, a fiber optic gyroscope, and wheel odometry. Additionally a 3D LIDAR is used for simultaneous localization and mapping (SLAM). A 3D map is built while concurrently a localization in a so far established 2D map is estimated with the current scan of the LIDAR. Despite of longer run-time of the SLAM algorithm compared to the EKF update, a high update rate is still guaranteed by sophisticatedly joining and synchronizing two parallel localization estimators.

Network simulation using the simulation language for alternate modeling (SLAM 2)

NASA Technical Reports Server (NTRS)

Shen, S.; Morris, D. W.

1983-01-01

The simulation language for alternate modeling (SLAM 2) is a general purpose language that combines network, discrete event, and continuous modeling capabilities in a single language system. The efficacy of the system's network modeling is examined and discussed. Examples are given of the symbolism that is used, and an example problem and model are derived. The results are discussed in terms of the ease of programming, special features, and system limitations. The system offers many features which allow rapid model development and provides an informative standardized output. The system also has limitations which may cause undetected errors and misleading reports unless the user is aware of these programming characteristics.

Neural network-based multiple robot simultaneous localization and mapping.

PubMed

Saeedi, Sajad; Paull, Liam; Trentini, Michael; Li, Howard

2011-12-01

In this paper, a decentralized platform for simultaneous localization and mapping (SLAM) with multiple robots is developed. Each robot performs single robot view-based SLAM using an extended Kalman filter to fuse data from two encoders and a laser ranger. To extend this approach to multiple robot SLAM, a novel occupancy grid map fusion algorithm is proposed. Map fusion is achieved through a multistep process that includes image preprocessing, map learning (clustering) using neural networks, relative orientation extraction using norm histogram cross correlation and a Radon transform, relative translation extraction using matching norm vectors, and then verification of the results. The proposed map learning method is a process based on the self-organizing map. In the learning phase, the obstacles of the map are learned by clustering the occupied cells of the map into clusters. The learning is an unsupervised process which can be done on the fly without any need to have output training patterns. The clusters represent the spatial form of the map and make further analyses of the map easier and faster. Also, clusters can be interpreted as features extracted from the occupancy grid map so the map fusion problem becomes a task of matching features. Results of the experiments from tests performed on a real environment with multiple robots prove the effectiveness of the proposed solution.

LiDAR Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments.

PubMed

Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha

2015-07-10

A new scan that matches an aided Inertial Navigation System (INS) with a low-cost LiDAR is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies-INS and LiDAR SLAM-into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform-NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment.

Structural Affects on the Slamming Pressures of High-Speed Planing Craft

NASA Astrophysics Data System (ADS)

Ikeda, Christine; Taravella, Brandon; Judge, Carolyn

2015-11-01

High-speed planing craft are subjected to repeated slamming events in waves that can be very extreme depending on the wave topography, impact angle of the ship, forward speed of the ship, encounter angle, and height out of the water. The current work examines this fluid-structure interaction problem through the use of wedge drop experiments and a CFD code. In the first set of experiments, a rigid 20-degree deadrise angle wedge was dropped from a range of heights (0 <= H <= 0 . 6 m) and while pressures and accelerations of the slam even were measured. The second set of experiments involved a flexible-bottom 15-degree deadrise angle wedge that was dropped from from the same range of heights. In these second experiments, the pressures, accelerations, and strain field were measured. Both experiments are compared with a non-linear boundary value flat cylinder theory code in order to compare the pressure loading. The code assumes a rigid structure, therefore, the results between the code and the first experiment are in good agreement. The second experiment shows pressure magnitudes that are lower than the predictions due to the energy required to deform the structure. Funding from University of New Orleans Office of Research and Sponsored Programs and the Office of Naval Research.

SLAMM: Visual monocular SLAM with continuous mapping using multiple maps

PubMed Central

Md. Sabri, Aznul Qalid; Loo, Chu Kiong; Mansoor, Ali Mohammed

2018-01-01

This paper presents the concept of Simultaneous Localization and Multi-Mapping (SLAMM). It is a system that ensures continuous mapping and information preservation despite failures in tracking due to corrupted frames or sensor’s malfunction; making it suitable for real-world applications. It works with single or multiple robots. In a single robot scenario the algorithm generates a new map at the time of tracking failure, and later it merges maps at the event of loop closure. Similarly, maps generated from multiple robots are merged without prior knowledge of their relative poses; which makes this algorithm flexible. The system works in real time at frame-rate speed. The proposed approach was tested on the KITTI and TUM RGB-D public datasets and it showed superior results compared to the state-of-the-arts in calibrated visual monocular keyframe-based SLAM. The mean tracking time is around 22 milliseconds. The initialization is twice as fast as it is in ORB-SLAM, and the retrieved map can reach up to 90 percent more in terms of information preservation depending on tracking loss and loop closure events. For the benefit of the community, the source code along with a framework to be run with Bebop drone are made available at https://github.com/hdaoud/ORBSLAMM. PMID:29702697

An Improved Otsu Threshold Segmentation Method for Underwater Simultaneous Localization and Mapping-Based Navigation

PubMed Central

Yuan, Xin; Martínez, José-Fernán; Eckert, Martina; López-Santidrián, Lourdes

2016-01-01

The main focus of this paper is on extracting features with SOund Navigation And Ranging (SONAR) sensing for further underwater landmark-based Simultaneous Localization and Mapping (SLAM). According to the characteristics of sonar images, in this paper, an improved Otsu threshold segmentation method (TSM) has been developed for feature detection. In combination with a contour detection algorithm, the foreground objects, although presenting different feature shapes, are separated much faster and more precisely than by other segmentation methods. Tests have been made with side-scan sonar (SSS) and forward-looking sonar (FLS) images in comparison with other four TSMs, namely the traditional Otsu method, the local TSM, the iterative TSM and the maximum entropy TSM. For all the sonar images presented in this work, the computational time of the improved Otsu TSM is much lower than that of the maximum entropy TSM, which achieves the highest segmentation precision among the four above mentioned TSMs. As a result of the segmentations, the centroids of the main extracted regions have been computed to represent point landmarks which can be used for navigation, e.g., with the help of an Augmented Extended Kalman Filter (AEKF)-based SLAM algorithm. The AEKF-SLAM approach is a recursive and iterative estimation-update process, which besides a prediction and an update stage (as in classical Extended Kalman Filter (EKF)), includes an augmentation stage. During navigation, the robot localizes the centroids of different segments of features in sonar images, which are detected by our improved Otsu TSM, as point landmarks. Using them with the AEKF achieves more accurate and robust estimations of the robot pose and the landmark positions, than with those detected by the maximum entropy TSM. Together with the landmarks identified by the proposed segmentation algorithm, the AEKF-SLAM has achieved reliable detection of cycles in the map and consistent map update on loop closure, which is shown in simulated experiments. PMID:27455279

An Improved Otsu Threshold Segmentation Method for Underwater Simultaneous Localization and Mapping-Based Navigation.

PubMed

Yuan, Xin; Martínez, José-Fernán; Eckert, Martina; López-Santidrián, Lourdes

2016-07-22

The main focus of this paper is on extracting features with SOund Navigation And Ranging (SONAR) sensing for further underwater landmark-based Simultaneous Localization and Mapping (SLAM). According to the characteristics of sonar images, in this paper, an improved Otsu threshold segmentation method (TSM) has been developed for feature detection. In combination with a contour detection algorithm, the foreground objects, although presenting different feature shapes, are separated much faster and more precisely than by other segmentation methods. Tests have been made with side-scan sonar (SSS) and forward-looking sonar (FLS) images in comparison with other four TSMs, namely the traditional Otsu method, the local TSM, the iterative TSM and the maximum entropy TSM. For all the sonar images presented in this work, the computational time of the improved Otsu TSM is much lower than that of the maximum entropy TSM, which achieves the highest segmentation precision among the four above mentioned TSMs. As a result of the segmentations, the centroids of the main extracted regions have been computed to represent point landmarks which can be used for navigation, e.g., with the help of an Augmented Extended Kalman Filter (AEKF)-based SLAM algorithm. The AEKF-SLAM approach is a recursive and iterative estimation-update process, which besides a prediction and an update stage (as in classical Extended Kalman Filter (EKF)), includes an augmentation stage. During navigation, the robot localizes the centroids of different segments of features in sonar images, which are detected by our improved Otsu TSM, as point landmarks. Using them with the AEKF achieves more accurate and robust estimations of the robot pose and the landmark positions, than with those detected by the maximum entropy TSM. Together with the landmarks identified by the proposed segmentation algorithm, the AEKF-SLAM has achieved reliable detection of cycles in the map and consistent map update on loop closure, which is shown in simulated experiments.

Associations of B cell-activating factor (BAFF) and anti-BAFF autoantibodies with disease activity in multi-ethnic Asian systemic lupus erythematosus patients in Singapore.

PubMed

Howe, H S; Thong, B Y H; Kong, K O; Chng, H H; Lian, T Y; Chia, F L; Tay, K S S; Lau, T C; Law, W G; Koh, E T; Leung, B P

2017-09-01

To measure the levels of B cell-activating factor (BAFF) and endogenous anti-BAFF autoantibodies in a cohort of multi-ethnic Asian systemic lupus erythematosus (SLE) patients in Singapore, to determine their correlation with disease activity. Serum samples from 121 SLE patients and 24 age- and sex-matched healthy controls were assayed for BAFF and anti-BAFF immunoglobulin (Ig)G antibody levels by enzyme-linked immunosorbent assay (ELISA). The lowest reliable detection limit for anti-BAFF-IgG antibody levels was defined as 2 standard deviations (s.d.) from blank. Correlation of serum BAFF and anti-BAFF IgG levels with disease activity [scored by SLE Activity Measure revised (SLAM-R)], and disease manifestations were determined in these 121 patients. SLE patients had elevated BAFF levels compared to controls; mean 820 ± 40 pg/ml and 152 pg ± 45/ml, respectively [mean ± standard error of the mean (s.e.m.), P < 0·01], which were correlated positively with anti-dsDNA antibody levels (r = 0·253, P < 0·03), and SLAM-R scores (r = 0·627, P < 0·01). In addition, SLE patients had significantly higher levels of anti-BAFF IgG, which were correlated negatively with disease activity (r = -0·436, P < 0·01), levels of anti-dsDNA antibody (r = -0·347, P < 0·02) and BAFF (r = -0·459, P < 0·01). The majority of patients in this multi-ethnic Asian SLE cohort had elevated levels of BAFF and anti-BAFF antibodies. Anti-BAFF autoantibody levels correlated negatively with clinical disease activity, anti-dsDNA and BAFF levels, suggesting that they may be disease-modifying. Our results provide further information about the complexity of BAFF pathophysiology in different SLE disease populations and phenotypes, and suggest that studies of the influence of anti-cytokine antibodies in different SLE populations will be required when selecting patients for trials using targeted anti-cytokine therapies. © 2017 British Society for Immunology.

Targeting Vaccine-Induced Extrafollicular Pathway of B Cell Differentiation Improves Rabies Postexposure Prophylaxis

PubMed Central

Haley, Shannon L.; Tzvetkov, Evgeni P.; Meuwissen, Samantha; Plummer, Joseph R.

2017-01-01

ABSTRACT Vaccine-induced B cells differentiate along two pathways. The follicular pathway gives rise to germinal centers (GCs) that can take weeks to fully develop. The extrafollicular pathway gives rise to short-lived plasma cells (PCs) that can rapidly secrete protective antibodies within days of vaccination. Rabies virus (RABV) postexposure prophylaxis (PEP) requires rapid vaccine-induced humoral immunity for protection. Therefore, we hypothesized that targeting extrafollicular B cell responses for activation would improve the speed and magnitude of RABV PEP. To test this hypothesis, we constructed, recovered, and characterized a recombinant RABV-based vaccine expressing murine B cell activating factor (BAFF) (rRABV-mBAFF). BAFF is an ideal molecule to improve early pathways of B cell activation, as it links innate and adaptive immunity, promoting potent B cell responses. Indeed, rRABV-mBAFF induced a faster, higher antibody response in mice and enhanced survivorship in PEP settings compared to rRABV. Interestingly, rRABV-mBAFF and rRABV induced equivalent numbers of GC B cells, suggesting that rRABV-mBAFF augmented the extrafollicular B cell pathway. To confirm that rRABV-mBAFF modulated the extrafollicular pathway, we used a signaling lymphocytic activation molecule (SLAM)-associated protein (SAP)-deficient mouse model. In response to antigen, SAP-deficient mice form extrafollicular B cell responses but do not generate GCs. rRABV-mBAFF induced similar anti-RABV antibody responses in SAP-deficient and wild-type mice, demonstrating that BAFF modulated immunity through the extrafollicular and not the GC B cell pathway. Collectively, strategies that manipulate pathways of B cell activation may facilitate the development of a single-dose RABV vaccine that replaces current complicated and costly RABV PEP. IMPORTANCE Effective RABV PEP is currently resource- and cost-prohibitive in regions of the world where RABV is most prevalent. In order to diminish the requirements for rabies immunoglobulin (RIG) and multiple vaccinations for effective prevention of clinical rabies, a more rapidly protective vaccine is needed. This work presents a successful approach to rapidly generate antibody-secreting PCs in response to vaccination by targeting the extrafollicular B cell pathway. We demonstrate that the improved early antibody responses induced by rRABV-mBAFF confer improved protection against RABV in a PEP model. Significantly, activation of the early extrafollicular B cell pathway, such as that demonstrated here, could improve the efficacy of vaccines targeting other pathogens against which rapid protection would decrease morbidity and mortality. PMID:28148792

Targeting Vaccine-Induced Extrafollicular Pathway of B Cell Differentiation Improves Rabies Postexposure Prophylaxis.

PubMed

Haley, Shannon L; Tzvetkov, Evgeni P; Meuwissen, Samantha; Plummer, Joseph R; McGettigan, James P

2017-04-15

Vaccine-induced B cells differentiate along two pathways. The follicular pathway gives rise to germinal centers (GCs) that can take weeks to fully develop. The extrafollicular pathway gives rise to short-lived plasma cells (PCs) that can rapidly secrete protective antibodies within days of vaccination. Rabies virus (RABV) postexposure prophylaxis (PEP) requires rapid vaccine-induced humoral immunity for protection. Therefore, we hypothesized that targeting extrafollicular B cell responses for activation would improve the speed and magnitude of RABV PEP. To test this hypothesis, we constructed, recovered, and characterized a recombinant RABV-based vaccine expressing murine B cell activating factor (BAFF) (rRABV-mBAFF). BAFF is an ideal molecule to improve early pathways of B cell activation, as it links innate and adaptive immunity, promoting potent B cell responses. Indeed, rRABV-mBAFF induced a faster, higher antibody response in mice and enhanced survivorship in PEP settings compared to rRABV. Interestingly, rRABV-mBAFF and rRABV induced equivalent numbers of GC B cells, suggesting that rRABV-mBAFF augmented the extrafollicular B cell pathway. To confirm that rRABV-mBAFF modulated the extrafollicular pathway, we used a signaling lymphocytic activation molecule (SLAM)-associated protein (SAP)-deficient mouse model. In response to antigen, SAP-deficient mice form extrafollicular B cell responses but do not generate GCs. rRABV-mBAFF induced similar anti-RABV antibody responses in SAP-deficient and wild-type mice, demonstrating that BAFF modulated immunity through the extrafollicular and not the GC B cell pathway. Collectively, strategies that manipulate pathways of B cell activation may facilitate the development of a single-dose RABV vaccine that replaces current complicated and costly RABV PEP. IMPORTANCE Effective RABV PEP is currently resource- and cost-prohibitive in regions of the world where RABV is most prevalent. In order to diminish the requirements for rabies immunoglobulin (RIG) and multiple vaccinations for effective prevention of clinical rabies, a more rapidly protective vaccine is needed. This work presents a successful approach to rapidly generate antibody-secreting PCs in response to vaccination by targeting the extrafollicular B cell pathway. We demonstrate that the improved early antibody responses induced by rRABV-mBAFF confer improved protection against RABV in a PEP model. Significantly, activation of the early extrafollicular B cell pathway, such as that demonstrated here, could improve the efficacy of vaccines targeting other pathogens against which rapid protection would decrease morbidity and mortality. Copyright © 2017 American Society for Microbiology.

A Primer on Autonomous Aerial Vehicle Design

PubMed Central

Coppejans, Hugo H. G.; Myburgh, Herman C.

2015-01-01

There is a large amount of research currently being done on autonomous micro-aerial vehicles (MAV), such as quadrotor helicopters or quadcopters. The ability to create a working autonomous MAV depends mainly on integrating a simultaneous localization and mapping (SLAM) solution with the rest of the system. This paper provides an introduction for creating an autonomous MAV for enclosed environments, aimed at students and professionals alike. The standard autonomous system and MAV automation are discussed, while we focus on the core concepts of SLAM systems and trajectory planning algorithms. The advantages and disadvantages of using remote processing are evaluated, and recommendations are made regarding the viability of on-board processing. Recommendations are made regarding best practices to serve as a guideline for aspirant MAV designers. PMID:26633410

A Primer on Autonomous Aerial Vehicle Design.

PubMed

Coppejans, Hugo H G; Myburgh, Herman C

2015-12-02

There is a large amount of research currently being done on autonomous micro-aerial vehicles (MAV), such as quadrotor helicopters or quadcopters. The ability to create a working autonomous MAV depends mainly on integrating a simultaneous localization and mapping (SLAM) solution with the rest of the system. This paper provides an introduction for creating an autonomous MAV for enclosed environments, aimed at students and professionals alike. The standard autonomous system and MAV automation are discussed, while we focus on the core concepts of SLAM systems and trajectory planning algorithms. The advantages and disadvantages of using remote processing are evaluated, and recommendations are made regarding the viability of on-board processing. Recommendations are made regarding best practices to serve as a guideline for aspirant MAV designers.

Evaluating Continuous-Time Slam Using a Predefined Trajectory Provided by a Robotic Arm

NASA Astrophysics Data System (ADS)

Koch, B.; Leblebici, R.; Martell, A.; Jörissen, S.; Schilling, K.; Nüchter, A.

2017-09-01

Recently published approaches to SLAM algorithms process laser sensor measurements and output a map as a point cloud of the environment. Often the actual precision of the map remains unclear, since SLAMalgorithms apply local improvements to the resulting map. Unfortunately, it is not trivial to compare the performance of SLAMalgorithms objectively, especially without an accurate ground truth. This paper presents a novel benchmarking technique that allows to compare a precise map generated with an accurate ground truth trajectory to a map with a manipulated trajectory which was distorted by different forms of noise. The accurate ground truth is acquired by mounting a laser scanner on an industrial robotic arm. The robotic arm is moved on a predefined path while the position and orientation of the end-effector tool are monitored. During this process the 2D profile measurements of the laser scanner are recorded in six degrees of freedom and afterwards used to generate a precise point cloud of the test environment. For benchmarking, an offline continuous-time SLAM algorithm is subsequently applied to remove the inserted distortions. Finally, it is shown that the manipulated point cloud is reversible to its previous state and is slightly improved compared to the original version, since small errors that came into account by imprecise assumptions, sensor noise and calibration errors are removed as well.

Accurate Initial State Estimation in a Monocular Visual–Inertial SLAM System

PubMed Central

Chen, Jing; Zhou, Zixiang; Leng, Zhen; Fan, Lei

2018-01-01

The fusion of monocular visual and inertial cues has become popular in robotics, unmanned vehicles and augmented reality fields. Recent results have shown that optimization-based fusion strategies outperform filtering strategies. Robust state estimation is the core capability for optimization-based visual–inertial Simultaneous Localization and Mapping (SLAM) systems. As a result of the nonlinearity of visual–inertial systems, the performance heavily relies on the accuracy of initial values (visual scale, gravity, velocity and Inertial Measurement Unit (IMU) biases). Therefore, this paper aims to propose a more accurate initial state estimation method. On the basis of the known gravity magnitude, we propose an approach to refine the estimated gravity vector by optimizing the two-dimensional (2D) error state on its tangent space, then estimate the accelerometer bias separately, which is difficult to be distinguished under small rotation. Additionally, we propose an automatic termination criterion to determine when the initialization is successful. Once the initial state estimation converges, the initial estimated values are used to launch the nonlinear tightly coupled visual–inertial SLAM system. We have tested our approaches with the public EuRoC dataset. Experimental results show that the proposed methods can achieve good initial state estimation, the gravity refinement approach is able to efficiently speed up the convergence process of the estimated gravity vector, and the termination criterion performs well. PMID:29419751

Laser-Based Slam with Efficient Occupancy Likelihood Map Learning for Dynamic Indoor Scenes

NASA Astrophysics Data System (ADS)

Li, Li; Yao, Jian; Xie, Renping; Tu, Jinge; Feng, Chen

2016-06-01

Location-Based Services (LBS) have attracted growing attention in recent years, especially in indoor environments. The fundamental technique of LBS is the map building for unknown environments, this technique also named as simultaneous localization and mapping (SLAM) in robotic society. In this paper, we propose a novel approach for SLAMin dynamic indoor scenes based on a 2D laser scanner mounted on a mobile Unmanned Ground Vehicle (UGV) with the help of the grid-based occupancy likelihood map. Instead of applying scan matching in two adjacent scans, we propose to match current scan with the occupancy likelihood map learned from all previous scans in multiple scales to avoid the accumulation of matching errors. Due to that the acquisition of the points in a scan is sequential but not simultaneous, there unavoidably exists the scan distortion at different extents. To compensate the scan distortion caused by the motion of the UGV, we propose to integrate a velocity of a laser range finder (LRF) into the scan matching optimization framework. Besides, to reduce the effect of dynamic objects such as walking pedestrians often existed in indoor scenes as much as possible, we propose a new occupancy likelihood map learning strategy by increasing or decreasing the probability of each occupancy grid after each scan matching. Experimental results in several challenged indoor scenes demonstrate that our proposed approach is capable of providing high-precision SLAM results.

Wildlife Reservoirs of Canine Distemper Virus Resulted in a Major Outbreak in Danish Farmed Mink (Neovison vison)

PubMed Central

Trebbien, Ramona; Chriel, Mariann; Struve, Tina; Hjulsager, Charlotte Kristiane; Larsen, Gitte; Larsen, Lars Erik

2014-01-01

A major outbreak of canine distemper virus (CDV) in Danish farmed mink (Neovison vison) started in the late summer period of 2012. At the same time, a high number of diseased and dead wildlife species such as foxes, raccoon dogs, and ferrets were observed. To track the origin of the outbreak virus full-length sequencing of the receptor binding surface protein hemagglutinin (H) was performed on 26 CDV's collected from mink and 10 CDV's collected from wildlife species. Subsequent phylogenetic analyses showed that the virus circulating in the mink farms and wildlife were highly identical with an identity at the nucleotide level of 99.45% to 100%. The sequences could be grouped by single nucleotide polymorphisms according to geographical distribution of mink farms and wildlife. The signaling lymphocytic activation molecule (SLAM) receptor binding region in most viruses from both mink and wildlife contained G at position 530 and Y at position 549; however, three mink viruses had an Y549H substitution. The outbreak viruses clustered phylogenetically in the European lineage and were highly identical to wildlife viruses from Germany and Hungary (99.29% – 99.62%). The study furthermore revealed that fleas (Ceratophyllus sciurorum) contained CDV and that vertical transmission of CDV occurred in a wild ferret. The study provides evidence that wildlife species, such as foxes, play an important role in the transmission of CDV to farmed mink and that the virus may be maintained in the wild animal reservoir between outbreaks. PMID:24454897

Design, Implementation and Validation of the Three-Wheel Holonomic Motion System of the Assistant Personal Robot (APR).

PubMed

Moreno, Javier; Clotet, Eduard; Lupiañez, Ruben; Tresanchez, Marcel; Martínez, Dani; Pallejà, Tomàs; Casanovas, Jordi; Palacín, Jordi

2016-10-10

This paper presents the design, implementation and validation of the three-wheel holonomic motion system of a mobile robot designed to operate in homes. The holonomic motion system is described in terms of mechanical design and electronic control. The paper analyzes the kinematics of the motion system and validates the estimation of the trajectory comparing the displacement estimated with the internal odometry of the motors and the displacement estimated with a SLAM procedure based on LIDAR information. Results obtained in different experiments have shown a difference on less than 30 mm between the position estimated with the SLAM and odometry, and a difference in the angular orientation of the mobile robot lower than 5° in absolute displacements up to 1000 mm.

Design, Implementation and Validation of the Three-Wheel Holonomic Motion System of the Assistant Personal Robot (APR)

PubMed Central

Moreno, Javier; Clotet, Eduard; Lupiañez, Ruben; Tresanchez, Marcel; Martínez, Dani; Pallejà, Tomàs; Casanovas, Jordi; Palacín, Jordi

2016-01-01

This paper presents the design, implementation and validation of the three-wheel holonomic motion system of a mobile robot designed to operate in homes. The holonomic motion system is described in terms of mechanical design and electronic control. The paper analyzes the kinematics of the motion system and validates the estimation of the trajectory comparing the displacement estimated with the internal odometry of the motors and the displacement estimated with a SLAM procedure based on LIDAR information. Results obtained in different experiments have shown a difference on less than 30 mm between the position estimated with the SLAM and odometry, and a difference in the angular orientation of the mobile robot lower than 5° in absolute displacements up to 1000 mm. PMID:27735857

Measles to the Rescue: A Review of Oncolytic Measles Virus

PubMed Central

Aref, Sarah; Bailey, Katharine; Fielding, Adele

2016-01-01

Oncolytic virotherapeutic agents are likely to become serious contenders in cancer treatment. The vaccine strain of measles virus is an agent with an impressive range of oncolytic activity in pre-clinical trials with increasing evidence of safety and efficacy in early clinical trials. This paramyxovirus vaccine has a proven safety record and is amenable to careful genetic modification in the laboratory. Overexpression of the measles virus (MV) receptor CD46 in many tumour cells may direct the virus to preferentially enter transformed cells and there is increasing awareness of the importance of nectin-4 and signaling lymphocytic activation molecule (SLAM) in oncolysis. Successful attempts to retarget MV by inserting genes for tumour-specific ligands to antigens such as carcinoembryonic antigen (CEA), CD20, CD38, and by engineering the virus to express synthetic microRNA targeting sequences, and “blinding” the virus to the natural viral receptors are exciting measures to increase viral specificity and enhance the oncolytic effect. Sodium iodine symporter (NIS) can also be expressed by MV, which enables in vivo tracking of MV infection. Radiovirotherapy using MV-NIS, chemo-virotherapy to convert prodrugs to their toxic metabolites, and immune-virotherapy including incorporating antibodies against immune checkpoint inhibitors can also increase the oncolytic potential. Anti-viral host immune responses are a recognized barrier to the success of MV, and approaches such as transporting MV to the tumour sites by carrier cells, are showing promise. MV Clinical trials are producing encouraging preliminary results in ovarian cancer, myeloma and cutaneous non-Hodgkin lymphoma, and the outcome of currently open trials in glioblastoma multiforme, mesothelioma and squamous cell carcinoma are eagerly anticipated. PMID:27782084

Measles to the Rescue: A Review of Oncolytic Measles Virus.

PubMed

Aref, Sarah; Bailey, Katharine; Fielding, Adele

2016-10-22

Oncolytic virotherapeutic agents are likely to become serious contenders in cancer treatment. The vaccine strain of measles virus is an agent with an impressive range of oncolytic activity in pre-clinical trials with increasing evidence of safety and efficacy in early clinical trials. This paramyxovirus vaccine has a proven safety record and is amenable to careful genetic modification in the laboratory. Overexpression of the measles virus (MV) receptor CD46 in many tumour cells may direct the virus to preferentially enter transformed cells and there is increasing awareness of the importance of nectin-4 and signaling lymphocytic activation molecule (SLAM) in oncolysis. Successful attempts to retarget MV by inserting genes for tumour-specific ligands to antigens such as carcinoembryonic antigen (CEA), CD20, CD38, and by engineering the virus to express synthetic microRNA targeting sequences, and "blinding" the virus to the natural viral receptors are exciting measures to increase viral specificity and enhance the oncolytic effect. Sodium iodine symporter (NIS) can also be expressed by MV, which enables in vivo tracking of MV infection. Radiovirotherapy using MV-NIS, chemo-virotherapy to convert prodrugs to their toxic metabolites, and immune-virotherapy including incorporating antibodies against immune checkpoint inhibitors can also increase the oncolytic potential. Anti-viral host immune responses are a recognized barrier to the success of MV, and approaches such as transporting MV to the tumour sites by carrier cells, are showing promise. MV Clinical trials are producing encouraging preliminary results in ovarian cancer, myeloma and cutaneous non-Hodgkin lymphoma, and the outcome of currently open trials in glioblastoma multiforme, mesothelioma and squamous cell carcinoma are eagerly anticipated.

Acoustic Event Detection and Classification

NASA Astrophysics Data System (ADS)

Temko, Andrey; Nadeu, Climent; Macho, Dušan; Malkin, Robert; Zieger, Christian; Omologo, Maurizio

The human activity that takes place in meeting rooms or classrooms is reflected in a rich variety of acoustic events (AE), produced either by the human body or by objects handled by humans, so the determination of both the identity of sounds and their position in time may help to detect and describe that human activity. Indeed, speech is usually the most informative sound, but other kinds of AEs may also carry useful information, for example, clapping or laughing inside a speech, a strong yawn in the middle of a lecture, a chair moving or a door slam when the meeting has just started. Additionally, detection and classification of sounds other than speech may be useful to enhance the robustness of speech technologies like automatic speech recognition.

Cutting Edge: 2B4-Mediated Coinhibition of CD4+ T Cells Underlies Mortality in Experimental Sepsis.

PubMed

Chen, Ching-Wen; Mittal, Rohit; Klingensmith, Nathan J; Burd, Eileen M; Terhorst, Cox; Martin, Greg S; Coopersmith, Craig M; Ford, Mandy L

2017-09-15

Sepsis is a leading cause of death in the United States, but the mechanisms underlying sepsis-induced immune dysregulation remain poorly understood. 2B4 (CD244, SLAM4) is a cosignaling molecule expressed predominantly on NK cells and memory CD8 + T cells that has been shown to regulate T cell function in models of viral infection and autoimmunity. In this article, we show that 2B4 signaling mediates sepsis lymphocyte dysfunction and mortality. 2B4 expression is increased on CD4 + T cells in septic animals and human patients at early time points. Importantly, genetic loss or pharmacologic inhibition of 2B4 significantly increased survival in a murine cecal ligation and puncture model. Further, CD4-specific conditional knockouts showed that 2B4 functions on CD4 + T cell populations in a cell-intrinsic manner and modulates adaptive and innate immune responses during sepsis. Our results illuminate a novel role for 2B4 coinhibitory signaling on CD4 + T cells in mediating immune dysregulation. Copyright © 2017 by The American Association of Immunologists, Inc.

Investigation of the potential for long-range transport of mercury to the Everglades using the organic chemistry integrated dispersion (ORCHID) model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, D.S.; Kienzle, M.A.; Ferris, D.C.

1996-12-31

The objective of this study is to identify potential long-range sources of mercury within the southeast region of the United States. Preliminary results of a climatological study using the Short-range Layered Atmospheric Model (SLAM) transport model from a select source in the southeast U.S. are presented. The potential for long-range transport from Oak Ridge, Tennessee to Florida is discussed. The transport and transformation of mercury during periods of favorable transport to south Florida is modeled using the Organic Chemistry Integrated Dispersion (ORCHID) model, which contains the transport model used in the climatology study. SLAM/ORCHID results indicate the potential for mercurymore » reaching southeast Florida from the source and the atmospheric oxidation of mercury during transport.« less

SLAM family markers are conserved among hematopoietic stem cells from old and reconstituted mice and markedly increase their purity

PubMed Central

Yilmaz, Ömer H.; Kiel, Mark J.; Morrison, Sean J.

2006-01-01

Recent advances have increased the purity of hematopoietic stem cells (HSCs) isolated from young mouse bone marrow. However, little attention has been paid to the purity of HSCs from other contexts. Although Thy-1lowSca-1+Lineage-c-kit+ cells from young bone marrow are highly enriched for HSCs (1 in 5 cells gives long-term multilineage reconstitution after transplantation into irradiated mice), the same population from old, reconstituted, or cytokine-mobilized mice engrafts much less efficiently (1 in 78 to 1 in 185 cells gives long-term multilineage reconstitution). To test whether we could increase the purity of HSCs isolated from these contexts, we examined the SLAM family markers CD150 and CD48. All detectable HSCs from old, reconstituted, and cyclophosphamide/G-CSF-mobilized mice were CD150+CD48-, just as in normal young bone marrow. Thy-1lowSca-1+Lineage-c-kit+ cells from old, reconstituted, or mobilized mice included mainly CD48+ and/or CD150- cells that lacked reconstituting ability. CD150+CD48-Sca-1+Lineage-c-kit+ cells from old, reconstituted, or mobilized mice were much more highly enriched for HSCs, with 1 in 3 to 1 in 7 cells giving long-term multilineage reconstitution. SLAM family receptor expression is conserved among HSCs from diverse contexts, and HSCs from old, reconstituted, and mobilized mice engraft relatively efficiently after transplantation when contaminating cells are eliminated. PMID:16219798

SLAM family markers are conserved among hematopoietic stem cells from old and reconstituted mice and markedly increase their purity.

PubMed

Yilmaz, Omer H; Kiel, Mark J; Morrison, Sean J

2006-02-01

Recent advances have increased the purity of hematopoietic stem cells (HSCs) isolated from young mouse bone marrow. However, little attention has been paid to the purity of HSCs from other contexts. Although Thy-1 low Sca-1+ Lineage- c-kit+ cells from young bone marrow are highly enriched for HSCs (1 in 5 cells gives long-term multilineage reconstitution after transplantation into irradiated mice), the same population from old, reconstituted, or cytokine-mobilized mice engrafts much less efficiently (1 in 78 to 1 in 185 cells gives long-term multilineage reconstitution). To test whether we could increase the purity of HSCs isolated from these contexts, we examined the SLAM family markers CD150 and CD48. All detectable HSCs from old, reconstituted, and cyclophosphamide/G-CSF-mobilized mice were CD150+ CD48-, just as in normal young bone marrow. Thy-1 low Sca-1+ Lineage- c-kit+ cells from old, reconstituted, or mobilized mice included mainly CD48+ and/or CD150- cells that lacked reconstituting ability. CD150+ CD48- Sca-1+ Lineage- c-kit+ cells from old, reconstituted, or mobilized mice were much more highly enriched for HSCs, with 1 in 3 to 1 in 7 cells giving long-term multilineage reconstitution. SLAM family receptor expression is conserved among HSCs from diverse contexts, and HSCs from old, reconstituted, and mobilized mice engraft relatively efficiently after transplantation when contaminating cells are eliminated.

a Preliminary Work on Layout Slam for Reconstruction of Indoor Corridor Environments

NASA Astrophysics Data System (ADS)

Baligh Jahromi, A.; Sohn, G.; Shahbazi, M.; Kang, J.

2017-09-01

We propose a real time indoor corridor layout estimation method based on visual Simultaneous Localization and Mapping (SLAM). The proposed method adopts the Manhattan World Assumption at indoor spaces and uses the detected single image straight line segments and their corresponding orthogonal vanishing points to improve the feature matching scheme in the adopted visual SLAM system. Using the proposed real time indoor corridor layout estimation method, the system is able to build an online sparse map of structural corner point features. The challenges presented by abrupt camera rotation in the 3D space are successfully handled through matching vanishing directions of consecutive video frames on the Gaussian sphere. Using the single image based indoor layout features for initializing the system, permitted the proposed method to perform real time layout estimation and camera localization in indoor corridor areas. For layout structural corner points matching, we adopted features which are invariant under scale, translation, and rotation. We proposed a new feature matching cost function which considers both local and global context information. The cost function consists of a unary term, which measures pixel to pixel orientation differences of the matched corners, and a binary term, which measures the amount of angle differences between directly connected layout corner features. We have performed the experiments on real scenes at York University campus buildings and the available RAWSEEDS dataset. The incoming results depict that the proposed method robustly performs along with producing very limited position and orientation errors.

Let microorganisms do the talking, let us talk more about microorganisms.

PubMed

Nai, Corrado; Magrini, Boris; Offe, Julia

2016-01-01

Microorganisms are of uttermost importance, yet in the eyes of the general public they are often associated with dirt and diseases. At the same time, microbiologists have access to and comprehensive knowledge of just a tiny minority of the microbial diversity existing in nature. In this commentary, we present these issues of public misconception and scientific limitations and their possible consequences, and propose ways to overcome them. A particular interest is directed toward the secondary metabolism of filamentous fungi as well as novel outreach activities, including so-called "science slams" and interactions between the arts and the sciences, to raise awareness about the relevance of microorganisms.

40 CFR 58.10 - Annual monitoring network plan and periodic network assessment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... part of SLAMS, NCore stations, STN stations, State speciation stations, SPM stations, and/or, in... analysis method(s) for each measured parameter. (4) The operating schedules for each monitor. (5) Any...

40 CFR 58.10 - Annual monitoring network plan and periodic network assessment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... part of SLAMS, NCore stations, STN stations, State speciation stations, SPM stations, and/or, in... and analysis method(s) for each measured parameter. (4) The operating schedules for each monitor. (5...

40 CFR 58.10 - Annual monitoring network plan and periodic network assessment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... part of SLAMS, NCore stations, STN stations, State speciation stations, SPM stations, and/or, in... and analysis method(s) for each measured parameter. (4) The operating schedules for each monitor. (5...

The Match of Her Life | NIH MedlinePlus the Magazine

MedlinePlus

... women. But with the same strength and positive attitude that helped her win 59 Grand Slam tennis ... as a tennis player has been a positive attitude. How has that translated to your dealing with ...

Smart watch RSSI localization and refinement for behavioral classification using laser-SLAM for mapping and fingerprinting.

PubMed

Carlson, Jay D; Mittek, Mateusz; Parkison, Steven A; Sathler, Pedro; Bayne, David; Psota, Eric T; Perez, Lance C; Bonasera, Stephen J

2014-01-01

As a first step toward building a smart home behavioral monitoring system capable of classifying a wide variety of human behavior, a wireless sensor network (WSN) system is presented for RSSI localization. The low-cost, non-intrusive system uses a smart watch worn by the user to broadcast data to the WSN, where the strength of the radio signal is evaluated at each WSN node to localize the user. A method is presented that uses simultaneous localization and mapping (SLAM) for system calibration, providing automated fingerprinting associating the radio signal strength patterns to the user's location within the living space. To improve the accuracy of localization, a novel refinement technique is introduced that takes into account typical movement patterns of people within their homes. Experimental results demonstrate that the system is capable of providing accurate localization results in a typical living space.

Floating shock fitting via Lagrangian adaptive meshes

NASA Technical Reports Server (NTRS)

Vanrosendale, John

1994-01-01

In recent works we have formulated a new approach to compressible flow simulation, combining the advantages of shock-fitting and shock-capturing. Using a cell-centered Roe scheme discretization on unstructured meshes, we warp the mesh while marching to steady state, so that mesh edges align with shocks and other discontinuities. This new algorithm, the Shock-fitting Lagrangian Adaptive Method (SLAM) is, in effect, a reliable shock-capturing algorithm which yields shock-fitted accuracy at convergence. Shock-capturing algorithms like this, which warp the mesh to yield shock-fitted accuracy, are new and relatively untried. However, their potential is clear. In the context of sonic booms, accurate calculation of near-field sonic boom signatures is critical to the design of the High Speed Civil Transport (HSCT). SLAM should allow computation of accurate N-wave pressure signatures on comparatively coarse meshes, significantly enhancing our ability to design low-boom configurations for high-speed aircraft.

Autonomous assistance navigation for robotic wheelchairs in confined spaces.

PubMed

Cheein, Fernando Auat; Carelli, Ricardo; De la Cruz, Celso; Muller, Sandra; Bastos Filho, Teodiano F

2010-01-01

In this work, a visual interface for the assistance of a robotic wheelchair's navigation is presented. The visual interface is developed for the navigation in confined spaces such as narrows corridors or corridor-ends. The interface performs two navigation modus: non-autonomous and autonomous. The non-autonomous driving of the robotic wheelchair is made by means of a hand-joystick. The joystick directs the motion of the vehicle within the environment. The autonomous driving is performed when the user of the wheelchair has to turn (90, 90 or 180 degrees) within the environment. The turning strategy is performed by a maneuverability algorithm compatible with the kinematics of the wheelchair and by the SLAM (Simultaneous Localization and Mapping) algorithm. The SLAM algorithm provides the interface with the information concerning the environment disposition and the pose -position and orientation-of the wheelchair within the environment. Experimental and statistical results of the interface are also shown in this work.

Comparison of orchid and OCD modeling SO{sub x} release in the Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferris, D.C.; Burns, D.S.; Steorts, W.L.

1996-10-01

Two atmospheric chemistry and transport models are used to investigate the atmospheric behavior of SO{sub x} in the Gulf of Mexico. SO{sub x} emissions from a location about 30 miles offshore in the Gulf of Mexico will be modeled with ENSCO`s Short-range Layered Atmospheric Model (SLAM) and the EPA and Material Management Service (MMS) sanctioned Offshore and Coastal Dispersion Model (OCD). The atmospheric chemistry associated with SLAM is modeled using ENSCO`s ORganic CHemistry Integrated Dispersion Model (ORCHID) and has been developed from the Carbon Bond Mechanism (CBM-IV) to characterize the behavior of SO{sub x} compounds in the environment. Model runsmore » from both ORCHID and OCD will be presented and compared. Predicted SO{sub x} concentrations will be compared with actual data gathered from the MMS`s SO{sub x} air quality study in 1993.« less

Underground localization using dual magnetic field sequence measurement and pose graph SLAM for directional drilling

NASA Astrophysics Data System (ADS)

Park, Byeolteo; Myung, Hyun

2014-12-01

With the development of unconventional gas, the technology of directional drilling has become more advanced. Underground localization is the key technique of directional drilling for real-time path following and system control. However, there are problems such as vibration, disconnection with external infrastructure, and magnetic field distortion. Conventional methods cannot solve these problems in real time or in various environments. In this paper, a novel underground localization algorithm using a re-measurement of the sequence of the magnetic field and pose graph SLAM (simultaneous localization and mapping) is introduced. The proposed algorithm exploits the property of the drilling system that the body passes through the previous pass. By comparing the recorded measurement from one magnetic sensor and the current re-measurement from another magnetic sensor, the proposed algorithm predicts the pose of the drilling system. The performance of the algorithm is validated through simulations and experiments.

Elucidating the Role of CD84 and AHR in Modulation of LPS-Induced Cytokines Production by Cruciferous Vegetable-Derived Compounds Indole-3-Carbinol and 3,3′-Diindolylmethane

PubMed Central

Wang, Thomas T. Y.; Pham, Quynhchi; Kim, Young S.

2018-01-01

Modulation of the immune system by cancer protective food bioactives has preventive and therapeutic importance in prostate cancer, but the mechanisms remain largely unclear. The current study tests the hypothesis that the diet-derived cancer protective compounds, indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM), affect the tumor microenvironment by regulation of inflammatory responses in monocytes and macrophages. We also ask whether I3C and DIM act through the aryl hydrocarbon (AHR)-dependent pathway or the signaling lymphocyte activation molecule (SLAM) family protein CD84-mediated pathway. The effect of I3C and DIM was examined using the human THP-1 monocytic cell in its un-differentiated (monocyte) and differentiated (macrophage) state. We observed that I3C and DIM inhibited lipopolysaccharide (LPS) induction of IL-1β mRNA and protein in the monocyte form but not the macrophage form of THP-1. Interestingly, CD84 mRNA but not protein was inhibited by I3C and DIM. AHR siRNA knockdown experiments confirmed that the inhibitory effects of I3C and DIM on IL-1β as well as CD84 mRNA are regulated through AHR-mediated pathways. Additionally, the AHR ligand appeared to differentially regulate other LPS-induced cytokines expression. Hence, cross-talk between AHR and inflammation-mediated pathways, but not CD84-mediated pathways, in monocytes but not macrophages may contribute to the modulation of tumor environments by I3C and DIM in prostate cancer. PMID:29364159

Emergence of canine distemper virus strains with modified molecular signature and enhanced neuronal tropism leading to high mortality in wild carnivores.

PubMed

Origgi, F C; Plattet, P; Sattler, U; Robert, N; Casaubon, J; Mavrot, F; Pewsner, M; Wu, N; Giovannini, S; Oevermann, A; Stoffel, M H; Gaschen, V; Segner, H; Ryser-Degiorgis, M-P

2012-11-01

An ongoing canine distemper epidemic was first detected in Switzerland in the spring of 2009. Compared to previous local canine distemper outbreaks, it was characterized by unusually high morbidity and mortality, rapid spread over the country, and susceptibility of several wild carnivore species. Here, the authors describe the associated pathologic changes and phylogenetic and biological features of a multiple highly virulent canine distemper virus (CDV) strain detected in and/or isolated from red foxes (Vulpes vulpes), Eurasian badgers (Meles meles), stone (Martes foina) and pine (Martes martes) martens, from a Eurasian lynx (Lynx lynx), and a domestic dog. The main lesions included interstitial to bronchointerstitial pneumonia and meningopolioencephalitis, whereas demyelination--the classic presentation of CDV infection--was observed in few cases only. In the brain lesions, viral inclusions were mainly in the nuclei of the neurons. Some significant differences in brain and lung lesions were observed between foxes and mustelids. Swiss CDV isolates shared together with a Hungarian CDV strain detected in 2004. In vitro analysis of the hemagglutinin protein from one of the Swiss CDV strains revealed functional and structural differences from that of the reference strain A75/17, with the Swiss strain showing increased surface expression and binding efficiency to the signaling lymphocyte activation molecule (SLAM). These features might be part of a novel molecular signature, which might have contributed to an increase in virus pathogenicity, partially explaining the high morbidity and mortality, the rapid spread, and the large host spectrum observed in this outbreak.

JAK2V617F expression in mice amplifies early hematopoietic cells and gives them a competitive advantage that is hampered by IFNα.

PubMed

Hasan, Salma; Lacout, Catherine; Marty, Caroline; Cuingnet, Marie; Solary, Eric; Vainchenker, William; Villeval, Jean-Luc

2013-08-22

The acquired gain-of-function V617F mutation in the Janus Kinase 2 (JAK2(V617F)) is the main mutation involved in BCR/ABL-negative myeloproliferative neoplasms (MPNs), but its effect on hematopoietic stem cells as a driver of disease emergence has been questioned. Therefore, we reinvestigated the role of endogenous expression of JAK2(V617F) on early steps of hematopoiesis as well as the effect of interferon-α (IFNα), which may target the JAK2(V617F) clone in humans by using knock-in mice with conditional expression of JAK2(V617F) in hematopoietic cells. These mice develop a MPN mimicking polycythemia vera with large amplification of myeloid mature and precursor cells, displaying erythroid endogenous growth and progressing to myelofibrosis. Interestingly, early hematopoietic compartments [Lin-, LSK, and SLAM (LSK/CD48-/CD150+)] increased with the age. Competitive repopulation assays demonstrated disease appearance and progressive overgrowth of myeloid, Lin-, LSK, and SLAM cells, but not lymphocytes, from a low number of engrafted JAK2(V617F) SLAM cells. Finally, IFNα treatment prevented disease development by specifically inhibiting JAK2(V617F) cells at an early stage of differentiation and eradicating disease-initiating cells. This study shows that JAK2(V617F) in mice amplifies not only late but also early hematopoietic cells, giving them a proliferative advantage through high cell cycling and low apoptosis that may sustain MPN emergence but is lost upon IFNα treatment.

a Fast and Flexible Method for Meta-Map Building for Icp Based Slam

NASA Astrophysics Data System (ADS)

Kurian, A.; Morin, K. W.

2016-06-01

Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM) is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP) algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.

Doing Business with the Naval Air Systems Command

DTIC Science & Technology

2014-08-13

Small Businesses (WOSB) — Economically Disadvantaged Women-Owned Small Business (EDWOSB) — Small Disadvantaged Businesses ( SDB ) — Service-Disabled...PRECISION STRIKE WEAPONS SDB II JDAM JSOW SLAM-ER HARPOON DIRECT ATTACK WEAPONS AAE/FC CAD/PAD ADVANCED DEVELOPMENT

Beyond Borders: Poetry Slicing through Steel Gates and Barbed Wires

ERIC Educational Resources Information Center

Jocson, Korina M.

2004-01-01

Exchange of poems at the 2nd Annual San Quentin/Patten College poetry slam with the prisoners is reported to be an event, which was extraordinaire. It was an opportunity to understand the hidden popular culture.

The Use of Shock Isolation mounts in Small High-Speed Craft to Protect Equipment from Wave Slam Effects

DTIC Science & Technology

2017-07-01

11 MOUNT RELATIVE DISPLACEMENT CALCULATIONS ......................................................... 13 Computational Methods...RELATIVE DISPLACEMENT AND MITIGATION RATIO...Predicted SDOF Responses ...................................................14 Figure 11. Predicted Relative Displacement for 3 Hz 30% Damped Mount

AUTOMATIC CALIBRATION OF A STOCHASTIC-LAGRANGIAN TRANSPORT MODEL (SLAM)

EPA Science Inventory

Numerical models are a useful tool in evaluating and designing NAPL remediation systems. Traditional constitutive finite difference and finite element models are complex and expensive to apply. For this reason, this paper presents the application of a simplified stochastic-Lagran...

A Fast Robot Identification and Mapping Algorithm Based on Kinect Sensor.

PubMed

Zhang, Liang; Shen, Peiyi; Zhu, Guangming; Wei, Wei; Song, Houbing

2015-08-14

Internet of Things (IoT) is driving innovation in an ever-growing set of application domains such as intelligent processing for autonomous robots. For an autonomous robot, one grand challenge is how to sense its surrounding environment effectively. The Simultaneous Localization and Mapping with RGB-D Kinect camera sensor on robot, called RGB-D SLAM, has been developed for this purpose but some technical challenges must be addressed. Firstly, the efficiency of the algorithm cannot satisfy real-time requirements; secondly, the accuracy of the algorithm is unacceptable. In order to address these challenges, this paper proposes a set of novel improvement methods as follows. Firstly, the ORiented Brief (ORB) method is used in feature detection and descriptor extraction. Secondly, a bidirectional Fast Library for Approximate Nearest Neighbors (FLANN) k-Nearest Neighbor (KNN) algorithm is applied to feature match. Then, the improved RANdom SAmple Consensus (RANSAC) estimation method is adopted in the motion transformation. In the meantime, high precision General Iterative Closest Points (GICP) is utilized to register a point cloud in the motion transformation optimization. To improve the accuracy of SLAM, the reduced dynamic covariance scaling (DCS) algorithm is formulated as a global optimization problem under the G2O framework. The effectiveness of the improved algorithm has been verified by testing on standard data and comparing with the ground truth obtained on Freiburg University's datasets. The Dr Robot X80 equipped with a Kinect camera is also applied in a building corridor to verify the correctness of the improved RGB-D SLAM algorithm. With the above experiments, it can be seen that the proposed algorithm achieves higher processing speed and better accuracy.

Hospital admissions for respiratory system diseases in adults with intellectual disabilities in Southeast London: a register-based cohort study.

PubMed

Chang, Chin-Kuo; Chen, Chih-Yin; Broadbent, Mathew; Stewart, Robert; O'Hara, Jean

2017-03-29

Intellectual disability (ID) carries a high impact on need for care, health status and premature mortality. Respiratory system diseases contribute a major part of mortality among people with ID, but remain underinvestigated as consequent morbidities. Anonymised electronic mental health records from the South London and Maudsley Trust (SLaM) were linked to national acute medical care data. Using retrospective cohort and matched case-control study designs, adults with ID receiving SLaM care between 1 January 2008 and 31 March 2013 were identified and compared with local catchment residents for respiratory system disease admissions. Standardised admission ratios (SARs) were first calculated, followed by a comparison of duration of hospitalisation with respiratory system disease between people with ID and age-matched and gender-matched random counterparts modelled using linear regression. Finally, the risk of readmission for respiratory system disease was analysed using the Cox models. For the 3138 adults with ID identified in SLaM, the SAR for respiratory system disease admissions was 4.02 (95% CI 3.79 to 4.26). Compared with adults without ID, duration of hospitalisation was significantly longer by 2.34 days (95% CI 0.03 to 4.64) and respiratory system disease readmission was significantly elevated (HR=1.35; 95% CI 1.17 to 1.56) after confounding adjustment. Respiratory system disease admissions in adults with ID are more frequent, of longer duration and have a higher likelihood of recurring. Development and evaluation of potential interventions to the preventable causes of respiratory diseases should be prioritised. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

"torino 1911" Project: a Contribution of a Slam-Based Survey to Extensive 3d Heritage Modeling

NASA Astrophysics Data System (ADS)

Chiabrando, F.; Della Coletta, C.; Sammartano, G.; Spanò, A.; Spreafico, A.

2018-05-01

In the framework of the digital documentation of complex environments the advanced Geomatics researches offers integrated solution and multi-sensor strategies for the 3D accurate reconstruction of stratified structures and articulated volumes in the heritage domain. The use of handheld devices for rapid mapping, both image- and range-based, can help the production of suitable easy-to use and easy-navigable 3D model for documentation projects. These types of reality-based modelling could support, with their tailored integrated geometric and radiometric aspects, valorisation and communication projects including virtual reconstructions, interactive navigation settings, immersive reality for dissemination purposes and evoking past places and atmospheres. The aim of this research is localized within the "Torino 1911" project, led by the University of San Diego (California) in cooperation with the PoliTo. The entire project is conceived for multi-scale reconstruction of the real and no longer existing structures in the whole park space of more than 400,000 m2, for a virtual and immersive visualization of the Turin 1911 International "Fabulous Exposition" event, settled in the Valentino Park. Particularly, in the presented research, a 3D metric documentation workflow is proposed and validated in order to integrate the potentialities of LiDAR mapping by handheld SLAM-based device, the ZEB REVO Real Time instrument by GeoSLAM (2017 release), instead of TLS consolidated systems. Starting from these kind of models, the crucial aspects of the trajectories performances in the 3D reconstruction and the radiometric content from imaging approaches are considered, specifically by means of compared use of common DSLR cameras and portable sensors.

Canine distemper virus in the Serengeti ecosystem: molecular adaptation to different carnivore species.

PubMed

Nikolin, Veljko M; Olarte-Castillo, Ximena A; Osterrieder, Nikolaus; Hofer, Heribert; Dubovi, Edward; Mazzoni, Camila J; Brunner, Edgar; Goller, Katja V; Fyumagwa, Robert D; Moehlman, Patricia D; Thierer, Dagmar; East, Marion L

2017-04-01

Was the 1993/1994 fatal canine distemper virus (CDV) epidemic in lions and spotted hyaenas in the Serengeti ecosystem caused by the recent spillover of a virulent domestic dog strain or one well adapted to these noncanids? We examine this question using sequence data from 13 'Serengeti' strains including five complete genomes obtained between 1993 and 2011. Phylogenetic and haplotype network analyses reveal that strains from noncanids during the epidemic were more closely related to each other than to those from domestic or wild canids. All noncanid 'Serengeti' strains during the epidemic encoded: (1) one novel substitution G134S in the CDV-V protein; and (2) the rare amino acid combination 519I/549H at two sites under positive selection in the region of the CDV-H protein that binds to SLAM (CD 150) host cell receptors. Worldwide, only a few noncanid strains in the America II lineage encode CDV-H 519I/549H. All canid 'Serengeti' strains during the epidemic coded CDV-V 134G, and CDV-H 519R/549Y, or 519R/549H. A functional assay of cell entry revealed the highest performance by CDV-H proteins encoding 519I/549H in cells expressing lion SLAM receptors, and the highest performance by proteins encoding 519R/549Y, typical of dog strains worldwide, in cells expressing dog SLAM receptors. Our findings are consistent with an epidemic in lions and hyaenas caused by CDV variants better adapted to noncanids than canids, but not with the recent spillover of a dog strain. Our study reveals a greater complexity of CDV molecular epidemiology in multihost environments than previously thought. © 2016 John Wiley & Sons Ltd.

IL10R1 loss-of-function alleles in rheumatoid arthritis and systemic lupus erythematosus.

PubMed

Hermann, J; Gruber, S; Neufeld, J B; Grundtner, P; Graninger, M; Graninger, W B; Berghold, A; Gasche, C

2009-01-01

IL-10 is a pleiotropic cytokine involved in the regulation of innate and cell-mediated immunity and a key mediator within the disturbed SLE immune system. IL-10 binds to IL10R1, which is expressed on a variety of immune cells and activates the JAK-STAT pathway. Two (out of several known) genetic IL10R1 variants may alter IL-10 binding or signal transduction. Here we investigate the differential activity of these IL10R1 variants and their possible association with RA or SLE susceptibility. IL10R1-wt, IL10R1-S138G, IL10R1-G330R, or IL10R1- S138G +G330R were cloned into pIRESpuro3 and transfected into HeLa cells. Single cell clones were tested for IL-10-induced SOCS3- and SLAM gene expression by real-time PCR. DNA from 182 RA patients, 222 SLE patients, and 250 healthy controls was genotyped by allele-specific PCR. A biphasic increase of SOCS3 mRNA was observed that peaked at 15 minutes and 4 hours after IL-10 stimulation. The presence of IL10R1 S138G and G330R showed a weaker induction of both SOCS3 and SLAM upon stimulation with IL-10. In RA a homozygous G330R genotype was more commonly present than in controls (15.4% vs. 7.6%; p<0.05). In SLE the G330R allele frequency was also increased (36.3% vs. 30.0%; p<0.05) without showing a gene-dose relationship at the genotype level. Based on these results, both variants of the IL10R1 gene are loss-of-function alleles. IL10R1 G330R may possibly contribute to RA or SLE disease susceptibility in Caucasian populations.

Slam Dunk

ERIC Educational Resources Information Center

Herek, Matthew

2011-01-01

There's nothing like a worldwide financial meltdown to kick-start an alumni association's career networking offerings. In 2009, the Northwestern University alumni board provided clear direction to its regional affiliates and to the full-time staff working at the Evanston, Illinois, campus: Develop ways to purposefully connect alumni with each…

Grand slam on cancer.

PubMed

Gartrell, Nanette

2014-01-01

A winner of 59 Grand Slam championships including a record 9 Wimbledon singles titles, Martina Navratilova is the most successful woman tennis player of the modern era. Martina was inducted into the International Tennis Hall of Fame, named "Tour Player of the Year" seven times by the Women's Tennis Association, declared "Female Athlete of the Year" by the Associated Press, and ranked one of the "Top Forty Athletes of All-Time" by Sports Illustrated. Equally accomplished off the court, Martina is an author, philanthropist, TV commentator, and activist who has dedicated her life to educating people about prejudice and stereotypes. After coming out as a lesbian in 1981, Martina became a tireless advocate of equal rights for lesbian, gay, bisexual, and transgender (LGBT) people, and she has contributed generously to the LGBT community. Martina is the author of seven books, including most recently Shape Your Self: My 6-Step Diet and Fitness Plan to Achieve the Best Shape of your Life, an inspiring guide to healthy living and personal fitness. Martina was diagnosed with breast cancer in 2010.

Intravital imaging by simultaneous label-free autofluorescence-multiharmonic microscopy.

PubMed

You, Sixian; Tu, Haohua; Chaney, Eric J; Sun, Yi; Zhao, Youbo; Bower, Andrew J; Liu, Yuan-Zhi; Marjanovic, Marina; Sinha, Saurabh; Pu, Yang; Boppart, Stephen A

2018-05-29

Intravital microscopy (IVM) emerged and matured as a powerful tool for elucidating pathways in biological processes. Although label-free multiphoton IVM is attractive for its non-perturbative nature, its wide application has been hindered, mostly due to the limited contrast of each imaging modality and the challenge to integrate them. Here we introduce simultaneous label-free autofluorescence-multiharmonic (SLAM) microscopy, a single-excitation source nonlinear imaging platform that uses a custom-designed excitation window at 1110 nm and shaped ultrafast pulses at 10 MHz to enable fast (2-orders-of-magnitude improvement), simultaneous, and efficient acquisition of autofluorescence (FAD and NADH) and second/third harmonic generation from a wide array of cellular and extracellular components (e.g., tumor cells, immune cells, vesicles, and vessels) in living tissue using only 14 mW for extended time-lapse investigations. Our work demonstrates the versatility and efficiency of SLAM microscopy for tracking cellular events in vivo, and is a major enabling advance in label-free IVM.

Under the Lens: Investigating the Sun's Mysteries

NASA Astrophysics Data System (ADS)

Harwood, William; Klotz, Irene

2008-11-01

Sometime around 2012, the waxing 11-year solar cycle once again will reach its peak. Between now and then, magnetically turbulent sunspots, spawned by some still mysterious process, will form near the poles in increasing numbers and migrate toward the Sun's faster-rotating equator in pairs of opposite polarity. Titanic magnetic storms will rage as immense flux tubes rise to the surface in active regions around sunspots and spread out in a boiling sea of electric charge. Magnetic field lines across an enormous range of scales will arc and undulate, rip apart and reconnect, heating the Sun's upper atmosphere and occasionally triggering brilliant flares and multibillion-megaton coronal mass ejections (CMEs) that travel through the solar wind and slam into Earth.

A development of intelligent entertainment robot for home life

NASA Astrophysics Data System (ADS)

Kim, Cheoltaek; Lee, Ju-Jang

2005-12-01

The purpose of this paper was to present the study and design idea for entertainment robot with educational purpose (IRFEE). The robot has been designed for home life considering dependability and interaction. The developed robot has three objectives - 1. Develop autonomous robot, 2. Design robot considering mobility and robustness, 3. Develop robot interface and software considering entertainment and education functionalities. The autonomous navigation was implemented by active vision based SLAM and modified EPF algorithm. The two differential wheels, the pan-tilt were designed mobility and robustness and the exterior was designed considering esthetic element and minimizing interference. The speech and tracking algorithm provided the good interface with human. The image transfer and Internet site connection is needed for service of remote connection and educational purpose.

Studies on Three-Dimensional Slamming on Slender Ships

DTIC Science & Technology

2007-05-10

Objectives This study is a joint effort among MIT, Seoul National University (SNU), and Korean Research Institute of Ships and Ocean Engineering ( KRISO ...model and laboratory experiments were carried out by SNU/ KRISO . The key responsibility of MIT is to investigate the feasibility and effectiveness of

Mixed Reality on a Virtual Globe

DTIC Science & Technology

2011-01-01

devices which can be inaccurate. However in a feature-based tracking system such as simultaneous localization and mapping ( SLAM ) (Durrant-Whyte & Bailey...or as complex as reconstruction from Light Detection and Ranging ( LIDAR ) sensing may be used to generate such a model. Many studies have been done to

CME leaving the Sun [Video

NASA Image and Video Library

2017-12-08

Animation of a CME leaving the Sun, slamming into our magnetosphere. Credit: NASA/GSFC/SOHO/ESA Sound: Juan Carlos Garcia To learn more go to the SOHO website: sohowww.nascom.nasa.gov/home.html To learn more about NASA's Sun Earth Day go here: sunearthday.nasa.gov/2010/index.php

Determining Directions of Ultrasound in Solids

NASA Technical Reports Server (NTRS)

Generazio, Edward R.; Roth, Don J.

1987-01-01

Ultrasound shadows cast by grooves. Improved method for determining direction of ultrasound in materials is shadow method using Scanning laser acoustic microscopy (SLAM). Direction of ultrasound calculated from dimensions of groove and portion of surface groove shields from ultrasound. Method has variety of applications in nontraditional quality-control applications.

Using SLAM to Look For the Dog Valley Fault, Truckee Area, California

NASA Astrophysics Data System (ADS)

Cronin, V. S.; Ashburn, J. A.; Sverdrup, K. A.

2014-12-01

The Truckee earthquake (9/12/1966, ML6.0) was a left-lateral event on a previously unrecognized NW-trending fault. The Prosser Creek and Boca Dams sustained damage, and the trace of the suspected causative fault passes near or through the site of the then-incomplete Stampede Dam. Another M6 earthquake occurred along the same general trend in 1948 with an epicenter in Dog Valley ~14 km to the NW of the 1966 epicenter. This trend is called the Dog Valley Fault (DVF), and its location on the ground surface is suggested by a prominent but broad zone of geomorphic lineaments near the cloud of aftershock epicenters determined for the 1966 event. Various ground effects of the 1966 event described by Kachadoorian et al. (1967) were located within this broad zone. The upper shoreface of reservoirs in the Truckee-Prosser-Martis basin are now exposed due to persistent drought. We have examined fault strands in a roadcut and exposed upper shoreface adjacent to the NE abutment of Stampede Dam. These are interpreted to be small-displacement splays associated with the DVF -- perhaps elements of the DVF damage zone. We have used the Seismo-Lineament Analysis Method (SLAM) to help us constrain the location of the DVF, based on earthquake focal mechanisms. Seismo-lineaments were computed, using recent revisions in the SLAM code (bearspace.baylor.edu/Vince_Cronin/www/SLAM/), for the 1966 main earthquake and for the better-recorded earthquakes of 7/3/1983 (M4) and 8/30/1992 (M3.2) that are inferred to have occurred along the DVF. Associated geomorphic analysis and some field reconnaissance identified a trend that might be associated with a fault, extending from the NW end of Prosser Creek Reservoir ~32° toward the Stampede Dam area. Triangle-strain analysis using horizontal velocities of local Plate Boundary Observatory GPS sites P146, P149, P150 and SLID indicates that the area rotates clockwise ~1-2°/Myr relative to the stable craton, as might be expected because the study area is within the Walker Lane transition zone between the Basin and Range and the Sierra Nevada-Great Valley Block. If the current seismogenic trace of the DVF is along the ~32° trend, perhaps the more prominent geomorphic lineaments traditionally associated with the DVF are inactive older features that are more strongly expressed on the landscape and that have rotated.

SLAM- and nectin-4-independent noncytolytic spread of canine distemper virus in astrocytes.

PubMed

Alves, Lisa; Khosravi, Mojtaba; Avila, Mislay; Ader-Ebert, Nadine; Bringolf, Fanny; Zurbriggen, Andreas; Vandevelde, Marc; Plattet, Philippe

2015-05-01

Measles and canine distemper viruses (MeV and CDV, respectively) first replicate in lymphatic and epithelial tissues by using SLAM and nectin-4 as entry receptors, respectively. The viruses may also invade the brain to establish persistent infections, triggering fatal complications, such as subacute sclerosis pan-encephalitis (SSPE) in MeV infection or chronic, multiple sclerosis-like, multifocal demyelinating lesions in the case of CDV infection. In both diseases, persistence is mediated by viral nucleocapsids that do not require packaging into particles for infectivity but are directly transmitted from cell to cell (neurons in SSPE or astrocytes in distemper encephalitis), presumably by relying on restricted microfusion events. Indeed, although morphological evidence of fusion remained undetectable, viral fusion machineries and, thus, a putative cellular receptor, were shown to contribute to persistent infections. Here, we first showed that nectin-4-dependent cell-cell fusion in Vero cells, triggered by a demyelinating CDV strain, remained extremely limited, thereby supporting a potential role of nectin-4 in mediating persistent infections in astrocytes. However, nectin-4 could not be detected in either primary cultured astrocytes or the white matter of tissue sections. In addition, a bioengineered "nectin-4-blind" recombinant CDV retained full cell-to-cell transmission efficacy in primary astrocytes. Combined with our previous report demonstrating the absence of SLAM expression in astrocytes, these findings are suggestive for the existence of a hitherto unrecognized third CDV receptor expressed by glial cells that contributes to the induction of noncytolytic cell-to-cell viral transmission in astrocytes. While persistent measles virus (MeV) infection induces SSPE in humans, persistent canine distemper virus (CDV) infection causes chronic progressive or relapsing demyelination in carnivores. Common to both central nervous system (CNS) infections is that persistence is based on noncytolytic cell-to-cell spread, which, in the case of CDV, was demonstrated to rely on functional membrane fusion machinery complexes. This inferred a mechanism where nucleocapsids are transmitted through macroscopically invisible microfusion events between infected and target cells. Here, we provide evidence that CDV induces such microfusions in a SLAM- and nectin-4-independent manner, thereby strongly suggesting the existence of a third receptor expressed in glial cells (referred to as GliaR). We propose that GliaR governs intercellular transfer of nucleocapsids and hence contributes to viral persistence in the brain and ensuing demyelinating lesions. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Multi-Target Tracking for Swarm vs. Swarm UAV Systems

DTIC Science & Technology

2012-09-01

Uhlmann, “Using covariance intersection for SLAM,” Robotics and Autonomous Systems, vol. 55, pp. 3–20, Jan. 2007. [10] R. B. G. Wolfgang Niehsen... Krause , J. Leskovec, and C. Guestrin, “Data association for topic intensity track- ing,” Proceedings of the 23rd international conference on Machine

Argentina: Background and U.S. Relations

DTIC Science & Technology

2008-11-05

Comercio Internacional, Y Culto, Comunicado de la Cancillería Argentina, September 11, 2008. 43 A. Rebossio, "Fernández Acusa al FBI de Desestablizar...Argentina," El País (Madrid), September 13, 2008. 44 “Argentina Slams Witness in Cash Suitcase Scandal,” Associated Press Newswires, November 4, 2008

A Monocular SLAM Method to Estimate Relative Pose During Satellite Proximity Operations

DTIC Science & Technology

2015-03-26

localization and mapping with efficient outlier handling. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), June 2013. 5. Herbert Bay...S.H. Spencer . Next generation advanced video guidance sensor. In Aerospace Conference, 2008 IEEE, pages 1–8, March 2008. 12. Michael Calonder, Vincent

Development and Validation of a Controlled Virtual Environment for Guidance, Navigation and Control of Quadrotor UAV

DTIC Science & Technology

2013-09-01

Width Modulation QuarC Quanser Real-time Control RC Remote Controlled RPV Remotely Piloted Vehicles SLAM Simultaneous Localization and Mapping UAV...development of the following systems: 1. Navigation (GPS, Lidar , etc.) 2. Communication (Datalink) 3. Ground Control Station (GUI, software programming

Educators Reach out to Katrina Victims

ERIC Educational Resources Information Center

Hardy, Lawrence

2006-01-01

The emotional trauma of recent events may never go away. A million people were uprooted by Hurricane Katrina, including an estimated 372,000 children of school age. Three weeks later, Hurricane Rita slammed into the Texas-Louisiana coastline, forcing thousands more to evacuate. Acute symptoms of trauma range from confusion, nightmares, and…

Fermilab Today

Science.gov Websites

September 2015 October 2015 November 2015 Classifieds Director's Corner Physics in a Nutshell Frontier Physics Slam gets good rap In Brief: A NALWO Thanksgiving Photo of the Day: Great ball of fire From difference between matter and antimatter From Physics, Nov. 23, 2015: Connecting the Higgs mass with cosmic

Astrophysics on the Lab Bench

ERIC Educational Resources Information Center

Hughes, Stephen W.

2010-01-01

In this article some basic laboratory bench experiments are described that are useful for teaching high school students some of the basic principles of stellar astrophysics. For example, in one experiment, students slam a plastic water-filled bottle down onto a bench, ejecting water towards the ceiling, illustrating the physics associated with a…

40 CFR 58.14 - System modification.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.14 System modification. (a) The State, or where... monitoring network that complies with the findings of the network assessments required every 5 years by § 58... schedule with respect to the SLAMS network are subject to the approval of the EPA Regional Administrator...

40 CFR 58.14 - System modification.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.14 System modification. (a) The State, or where... monitoring network that complies with the findings of the network assessments required every 5 years by § 58... schedule with respect to the SLAMS network are subject to the approval of the EPA Regional Administrator...

40 CFR 58.11 - Network technical requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Network technical requirements. 58.11... (CONTINUED) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.11 Network technical requirements. (a)(1... A to this part when operating the SLAMS networks. (2) Beginning January 1, 2009, State and local...

40 CFR 58.11 - Network technical requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Network technical requirements. 58.11... (CONTINUED) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.11 Network technical requirements. (a)(1... A to this part when operating the SLAMS networks. (2) Beginning January 1, 2009, State and local...

Structural Influence of Dynamics of Bottom Loads

DTIC Science & Technology

2014-02-10

using the Numerette research craft, are underway. Early analytic research on slamming was done by von Karman [5] using a momentum approach, and by...pressure q{x,t) as two constant pressures, qi and qj, traveling at a constant speed c. Using the Euler- Bernoulli beam assumptions the governing

COMPARISON OF OZONE INDICATORS MONITORED AT CASTNET AND RURALLY - DESIGNATED SLAMS SITES

EPA Science Inventory

Many water-bodies within the United States are contaminated by non-point source (NPS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic 13romses. One such NPS pollutant is fe...

Vision Based SLAM in Dynamic Scenes

DTIC Science & Technology

2012-12-20

the correct relative poses between cameras at frame F. For this purpose, we detect and match SURF features between cameras in dilierent groups, and...all cameras in s uch a challenging case. For a compa rison, we disabled the ’ inte r-camera pose estimation’ and applied the ’ intra-camera pose esti

Don't Spoil the Promise of Cooperative Learning: Response to Slavin.

ERIC Educational Resources Information Center

Kohn, Alfie

1991-01-01

Responding to Slavin's critique of Kohn's article (in the same "Educational Leadership" issue) condemning cooperative rewards, Kohn slams Slavin's faulty research interpretations. Slavin may be correct that few non-reward-based classrooms exist in the U.S., but this hardly demonstrates that the best alternative to bribing individuals is to bribe…

Just "Slammin!" Adolescents' Construction of Identity through Performance Poetry

ERIC Educational Resources Information Center

Rudd, Lynn L.

2012-01-01

Using a case study design, this study investigated the literacy identity, both collectively and individually, of the members of "Slammin!", a slam poetry team from an urban high school. Participant observation of practices and performances was used to find how the involvement in this group uniquely impacted students' academic and personal lives.…

Rating Slam Dunks to Visualize the Mean, Median, Mode, Range, and Standard Deviation

ERIC Educational Resources Information Center

Robinson, Nick W.; Castle Bell, Gina

2014-01-01

Among the many difficulties beleaguering the communication research methods instructor is the problem of contextualizing abstract ideas. Comprehension of variable operationalization, the utility of the measures of central tendency, measures of dispersion, and the visual distribution of data sets are difficult, since students have not handled data.…

The Saint Louis River Idea-Slam crowd sourcing good ideas for the Saint Louis River

EPA Science Inventory

As part of the 2017 Saint Louis River Summit, we propose hosting an “Idea-Slam” using software originally developed by the U.S. Consumer Financial Protection Bureau. Idea-box is an open source online app/website used to collect and surface ideas from members of an or...

The Simulation of Wave Slam Impulses to Evaluate Shock Mitigation Seats For High-Speed Planing Craft

DTIC Science & Technology

2013-05-17

Vibration Handbook Fourth Edition”, McGraw Hill, New York, Chicago , San Francisco, 1996 29. Riley, M., Coats, T., Haupt, K., Jacobson, D., “The...United States Coast Guard Office of Boat Forces, CG 731 2100 Second Street, SW STOP 356 Washington, DC 20593-7356 Attn: David Shepard

Automated Driftmeter Fused with Inertial Navigation

DTIC Science & Technology

2014-03-27

6 IMU Inertial Measurement Unit . . . . . . . . . . . . . . . . . . . . . . . 7 SLAM Simultaneous...timing lines to remain horizontal at all times, regardless of turbulence and within 20 degrees of roll , pitch, and yaw of the aircraft. It had two...introduced in 1960 [2]. The Kalman filter algorithm has been used to merge inertial navigational data from Inertial Measurement Units ( IMU ) with

40 CFR Appendix A to Part 58 - Quality Assurance Requirements for SLAMS, SPMs and PSD Air Monitoring

Code of Federal Regulations, 2010 CFR

2010-07-01

... quality system in terms of the organizational structure, functional responsibilities of management and... more stringent requirements. Monitoring organizations may, based on their quality objectives, develop... infrequent work with EPA funds may combine the QMP with the QAPP based on negotiations with the funding...

Sensible Driving Saves More Gas than Drivers Think

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

It’s common knowledge that driving aggressively can dent gas mileage, but it’s difficult to determine exactly how much gas drivers waste. A new study by researchers at the Department of Energy’s Oak Ridge National Laboratory has quantified the impact speeding and slamming on the brakes has on fuel economy and consumption.

School Construction Summer Slam

ERIC Educational Resources Information Center

Jensen, Richard F.

2012-01-01

Every school has a list of renovations, upgrades and repairs that need attention, but many are too distracting and disruptive to carry out during the school year. Often, the best time to address these nagging construction projects is during the summer when students are on break and the campus is quieter. Although these "summer slammers" often are…

BatSLAM: Simultaneous localization and mapping using biomimetic sonar.

PubMed

Steckel, Jan; Peremans, Herbert

2013-01-01

We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building.

BatSLAM: Simultaneous Localization and Mapping Using Biomimetic Sonar

PubMed Central

Steckel, Jan; Peremans, Herbert

2013-01-01

We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building. PMID:23365647

Preparing African Americans for careers in health care: the Jackson Heart Study.

PubMed

Srinivasan, Asoka; Brown, James; Fahmy, Nimr; Heitman, Elizabeth; Singh, Madhu; Szklo, Moyses; Taylor, Herman; White, Wendy

2005-01-01

The Jackson Heart Study Undergraduate Training Center (UTC) at Tougaloo College was developed to increase the numbers of African-American students entering public health and health related fields. The UTC includes a scholars program for undergraduate students at Tougaloo College, three four-week programs for high school students called the SLAM (science, language arts, and mathematics) workshops, and an introductory epidemiology course for healthcare professionals and graduate students. The scholars program recruits 12 Tougaloo College freshmen annually for the duration of their undergraduate education. As of the 2005 summer, 512 students have enrolled in the SLAM workshops. The introduction to epidemiology course has provided training for 155 individuals from 1999 to 2004. This paper documents the need for this program based on the conspicuously small proportion of African Americans who are health practitioners in Mississippi. The content and selection process for each program is described, and a summary of the enrollment history, characteristics of the program participants, and their accomplishments is presented. Finally, the methods of program assessment and tracking are discussed.

Numerical Evaluation of Dynamic Response for Flexible Composite Structures under Slamming Impact for Naval Applications

NASA Astrophysics Data System (ADS)

Hassoon, O. H.; Tarfaoui, M.; El Moumen, A.; Benyahia, H.; Nachtane, M.

2018-06-01

The deformable composite structures subjected to water-entry impact can be caused a phenomenon called hydroelastic effect, which can modified the fluid flow and estimated hydrodynamic loads comparing with rigid body. This is considered very important for ship design engineers to predict the global and the local hydrodynamic loads. This paper presents a numerical model to simulate the slamming water impact of flexible composite panels using an explicit finite element method. In order to better describe the hydroelastic influence and mechanical properties, composite materials panels with different stiffness and under different impact velocities with deadrise angle of 100 have been studied. In the other hand, the inertia effect was observed in the early stage of the impact that relative to the loading rate. Simulation results have been indicated that the lower stiffness panel has a higher hydroelastic effect and becomes more important when decreasing of the deadrise angle and increasing the impact velocity. Finally, the simulation results were compared with the experimental data and the analytical approaches of the rigid body to describe the behavior of the hydroelastic influence.

Numerical simulation of the wave-induced non-linear bending moment of ships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, J.; Wang, Z.; Gu, X.

1995-12-31

Ships traveling in moderate or rough seas may experience non-linear bending moments due to flare effect and slamming loads. The numerical simulation of the total wave-induced bending moment contributed from both the wave frequency component induced by wave forces and the high frequency whipping component induced by slamming actions is very important in predicting the responses and ensuring the safety of the ship in rough seas. The time simulation is also useful for the reliability analysis of ship girder strength. The present paper discusses four different methods of the numerical simulation of wave-induced non-linear vertical bending moment of ships recentlymore » developed in CSSRC, including the hydroelastic integral-differential method (HID), the hydroelastic differential analysis method (HDA), the combined seakeeping and structural forced vibration method (CSFV), and the modified CSFV method (MCSFV). Numerical predictions are compared with the experimental results obtained from the elastic ship model test of S-175 container ship in regular and irregular waves presented by Watanabe Ueno and Sawada (1989).« less

Numerical Evaluation of Dynamic Response for Flexible Composite Structures under Slamming Impact for Naval Applications

NASA Astrophysics Data System (ADS)

Hassoon, O. H.; Tarfaoui, M.; El Moumen, A.; Benyahia, H.; Nachtane, M.

2017-10-01

The deformable composite structures subjected to water-entry impact can be caused a phenomenon called hydroelastic effect, which can modified the fluid flow and estimated hydrodynamic loads comparing with rigid body. This is considered very important for ship design engineers to predict the global and the local hydrodynamic loads. This paper presents a numerical model to simulate the slamming water impact of flexible composite panels using an explicit finite element method. In order to better describe the hydroelastic influence and mechanical properties, composite materials panels with different stiffness and under different impact velocities with deadrise angle of 100 have been studied. In the other hand, the inertia effect was observed in the early stage of the impact that relative to the loading rate. Simulation results have been indicated that the lower stiffness panel has a higher hydroelastic effect and becomes more important when decreasing of the deadrise angle and increasing the impact velocity. Finally, the simulation results were compared with the experimental data and the analytical approaches of the rigid body to describe the behavior of the hydroelastic influence.

On-patient see-through augmented reality based on visual SLAM.

PubMed

Mahmoud, Nader; Grasa, Óscar G; Nicolau, Stéphane A; Doignon, Christophe; Soler, Luc; Marescaux, Jacques; Montiel, J M M

2017-01-01

An augmented reality system to visualize a 3D preoperative anatomical model on intra-operative patient is proposed. The hardware requirement is commercial tablet-PC equipped with a camera. Thus, no external tracking device nor artificial landmarks on the patient are required. We resort to visual SLAM to provide markerless real-time tablet-PC camera location with respect to the patient. The preoperative model is registered with respect to the patient through 4-6 anchor points. The anchors correspond to anatomical references selected on the tablet-PC screen at the beginning of the procedure. Accurate and real-time preoperative model alignment (approximately 5-mm mean FRE and TRE) was achieved, even when anchors were not visible in the current field of view. The system has been experimentally validated on human volunteers, in vivo pigs and a phantom. The proposed system can be smoothly integrated into the surgical workflow because it: (1) operates in real time, (2) requires minimal additional hardware only a tablet-PC with camera, (3) is robust to occlusion, (4) requires minimal interaction from the medical staff.

[Use of psychostimulants in a sexual context: Analysis of cases reported to the French network of Addictovigilance Centers].

PubMed

Batisse, Anne; Peyrière, Hélène; Eiden, Céline; Courné, Marie-Anne; Djezzar, Samira

2016-10-01

The "SLAM" phenomenon is an increasingly popular practice, in Paris and London gay scene, defined by 3 characteristics: injection, sexual party and psychostimulant drugs. The French Medical Agency requested a risk assessment of "SLAM" and more broadly of the use of psychostimulants in a sexual context, by the analysis of complications related to this practice notified to the French Network of Addictovigilance Centers. All cases of complications related to "SLAM" practice, including cases of abuse or dependence, and somatic and psychiatric complications, were analysed. Between January 2008 to December 2013, 51 cases were collected. Users were exclusively men, with a mean age of 40 years, having psychostimulants exposure in a sexual context, mainly in men who have sex with men (MSM) context (100%, n=35). The prevalence of human immunodeficiency virus (HIV) infection was 82% (n=32) with a high level of HIV/hepatitis C virus (HCV) co-infection (50%, n=16). The main psychostimulants reported are synthetic cathinones (89.5%). Cathinones users tended to be polydrug users: 62% also reported use other than psychoactive substances (gamma-butyrolactone [GBL], ketamine, methylenedioxyméthamphetamine [MDMA], lysergic acid diethylamide [LSD]…). The main complications were psychiatric disorders in 50% (psychotic symptoms, agitation, anxiety, suicidal ideas or attempt and forensic problems), acute intoxication in 25% (including 3 deaths), dependence and abuse in 17% and infectious complications in 8% (viral seroconversion). Health professionals as well as users should be aware of the physical (cardiovascular) and behavioural (psychic, fast dependence syndrome) toxicity of cathinones. Risk reduction policy must be targeted to the population of MSM with specific interventions both on risky sexual behavior and substance use. Copyright © 2016 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

Solving Navigational Uncertainty Using Grid Cells on Robots

PubMed Central

Milford, Michael J.; Wiles, Janet; Wyeth, Gordon F.

2010-01-01

To successfully navigate their habitats, many mammals use a combination of two mechanisms, path integration and calibration using landmarks, which together enable them to estimate their location and orientation, or pose. In large natural environments, both these mechanisms are characterized by uncertainty: the path integration process is subject to the accumulation of error, while landmark calibration is limited by perceptual ambiguity. It remains unclear how animals form coherent spatial representations in the presence of such uncertainty. Navigation research using robots has determined that uncertainty can be effectively addressed by maintaining multiple probabilistic estimates of a robot's pose. Here we show how conjunctive grid cells in dorsocaudal medial entorhinal cortex (dMEC) may maintain multiple estimates of pose using a brain-based robot navigation system known as RatSLAM. Based both on rodent spatially-responsive cells and functional engineering principles, the cells at the core of the RatSLAM computational model have similar characteristics to rodent grid cells, which we demonstrate by replicating the seminal Moser experiments. We apply the RatSLAM model to a new experimental paradigm designed to examine the responses of a robot or animal in the presence of perceptual ambiguity. Our computational approach enables us to observe short-term population coding of multiple location hypotheses, a phenomenon which would not be easily observable in rodent recordings. We present behavioral and neural evidence demonstrating that the conjunctive grid cells maintain and propagate multiple estimates of pose, enabling the correct pose estimate to be resolved over time even without uniquely identifying cues. While recent research has focused on the grid-like firing characteristics, accuracy and representational capacity of grid cells, our results identify a possible critical and unique role for conjunctive grid cells in filtering sensory uncertainty. We anticipate our study to be a starting point for animal experiments that test navigation in perceptually ambiguous environments. PMID:21085643

Recent advances in vibro-impact dynamics and collision of ocean vessels

NASA Astrophysics Data System (ADS)

Ibrahim, Raouf A.

2014-11-01

The treatment of ship impacts and collisions takes different approaches depending on the emphasis of each discipline. For example, dynamicists, physicist, and mathematicians are dealing with developing analytical models and mappings of vibro-impact systems. On the other hand, naval architects and ship designers are interested in developing design codes and structural assessments due to slamming loads, liquid sloshing impact loads in liquefied natural gas tanks and ship grounding accidents. The purpose of this review is to highlight the main differences of the two disciplines. It begins with a brief account of the theory of vibro-impact dynamics based on modeling and mapping of systems experiencing discontinuous changes in their state of motion due to collision. The main techniques used in modeling include power-law phenomenological modeling, Hertzian modeling, and non-smooth coordinate transformations originally developed by Zhuravlev and Ivanov. In view of their effectiveness, both Zhuravlev and Ivanov non-smooth coordinate transformations will be described and assessed for the case of ship roll dynamics experiencing impact with rigid barriers. These transformations have the advantage of converting the vibro-impact oscillator into an oscillator without barriers such that the corresponding equation of motion does not contain any impact term. One of the recent results dealing with the coefficient of restitution is that its value monotonically decreases with the impact velocity and not unique but random in nature. Slamming loads and grounding events of ocean waves acting on the bottom of high speed vessels will be assessed with reference to the ship structural damage. It will be noticed that naval architects and marine engineers are treating these problems using different approaches from those used by dynamicists. The problem of sloshing impact in liquefied natural gas cargo and related problems will be assessed based on the numerical and experimental results. It is important for vessel designers to determine the capacity of ships to resist random slamming loads, sloshing loading impact, grounding accidents and ships collisions.

Molecular Pathogenesis of EBV Susceptibility in XLP as Revealed by Analysis of Female Carriers with Heterozygous Expression of SAP

PubMed Central

Palendira, Umaimainthan; Low, Carol; Chan, Anna; Hislop, Andrew D.; Ho, Edwin; Phan, Tri Giang; Deenick, Elissa; Cook, Matthew C.; Riminton, D. Sean; Choo, Sharon; Loh, Richard; Alvaro, Frank; Booth, Claire; Gaspar, H. Bobby; Moretta, Alessandro; Khanna, Rajiv; Rickinson, Alan B.; Tangye, Stuart G.

2011-01-01

X-linked lymphoproliferative disease (XLP) is a primary immunodeficiency caused by mutations in SH2D1A which encodes SAP. SAP functions in signalling pathways elicited by the SLAM family of leukocyte receptors. A defining feature of XLP is exquisite sensitivity to infection with EBV, a B-lymphotropic virus, but not other viruses. Although previous studies have identified defects in lymphocytes from XLP patients, the unique role of SAP in controlling EBV infection remains unresolved. We describe a novel approach to this question using female XLP carriers who, due to random X-inactivation, contain both SAP+ and SAP− cells. This represents the human equivalent of a mixed bone marrow chimera in mice. While memory CD8+ T cells specific for CMV and influenza were distributed across SAP+ and SAP− populations, EBV-specific cells were exclusively SAP+. The preferential recruitment of SAP+ cells by EBV reflected the tropism of EBV for B cells, and the requirement for SAP expression in CD8+ T cells for them to respond to Ag-presentation by B cells, but not other cell types. The inability of SAP− clones to respond to Ag-presenting B cells was overcome by blocking the SLAM receptors NTB-A and 2B4, while ectopic expression of NTB-A on fibroblasts inhibited cytotoxicity of SAP− CD8+ T cells, thereby demonstrating that SLAM receptors acquire inhibitory function in the absence of SAP. The innovative XLP carrier model allowed us to unravel the mechanisms underlying the unique susceptibility of XLP patients to EBV infection in the absence of a relevant animal model. We found that this reflected the nature of the Ag-presenting cell, rather than EBV itself. Our data also identified a pathological signalling pathway that could be targeted to treat patients with severe EBV infection. This system may allow the study of other human diseases where heterozygous gene expression from random X-chromosome inactivation can be exploited. PMID:22069374

Autonomous localisation of rovers for future planetary exploration

NASA Astrophysics Data System (ADS)

Bajpai, Abhinav

Future Mars exploration missions will have increasingly ambitious goals compared to current rover and lander missions. There will be a need for extremely long distance traverses over shorter periods of time. This will allow more varied and complex scientific tasks to be performed and increase the overall value of the missions. The missions may also include a sample return component, where items collected on the surface will be returned to a cache in order to be returned to Earth, for further study. In order to make these missions feasible, future rover platforms will require increased levels of autonomy, allowing them to operate without heavy reliance on a terrestrial ground station. Being able to autonomously localise the rover is an important element in increasing the rover's capability to independently explore. This thesis develops a Planetary Monocular Simultaneous Localisation And Mapping (PM-SLAM) system aimed specifically at a planetary exploration context. The system uses a novel modular feature detection and tracking algorithm called hybrid-saliency in order to achieve robust tracking, while maintaining low computational complexity in the SLAM filter. The hybrid saliency technique uses a combination of cognitive inspired saliency features with point-based feature descriptors as input to the SLAM filter. The system was tested on simulated datasets generated using the Planetary, Asteroid and Natural scene Generation Utility (PANGU) as well as two real world datasets which closely approximated images from a planetary environment. The system was shown to provide a higher accuracy of localisation estimate than a state-of-the-art VO system tested on the same data set. In order to be able to localise the rover absolutely, further techniques are investigated which attempt to determine the rover's position in orbital maps. Orbiter Mask Matching uses point-based features detected by the rover to associate descriptors with large features extracted from orbital imagery and stored in the rover memory prior the mission launch. A proof of concept is evaluated using a PANGU simulated boulder field.

Expansion of somatically reverted memory CD8+ T cells in patients with X-linked lymphoproliferative disease caused by selective pressure from Epstein-Barr virus

PubMed Central

Low, Carol; Bell, Andrew I.; Abbott, Rachel J.M.; Phan, Tri Giang; Riminton, D. Sean; Choo, Sharon; Smart, Joanne M.; Lougaris, Vassilios; Giliani, Silvia; Buckley, Rebecca H.; Grimbacher, Bodo; Alvaro, Frank; Klion, Amy D.; Nichols, Kim E.; Adelstein, Stephen; Rickinson, Alan B.

2012-01-01

Patients with the primary immunodeficiency X-linked lymphoproliferative disease (XLP), which is caused by mutations in SH2D1A, are highly susceptible to Epstein-Barr virus (EBV) infection. Nonetheless, some XLP patients demonstrate less severe clinical manifestations after primary infection. SH2D1A encodes the adaptor molecule SLAM-associated protein (SAP), which is expressed in T and natural killer cells and is required for cytotoxicity against B cells, the reservoir for EBV. It is not known why the clinical presentation of XLP is so variable. In this study, we report for the first time the occurrence of somatic reversion in XLP. Reverted SAP-expressing cells resided exclusively within the CD8+ T cell subset, displayed a CD45RA−CCR7− effector memory phenotype, and were maintained at a stable level over time. Importantly, revertant CD8+ SAP+ T cells, but not SAP− cells, proliferated in response to EBV and killed EBV-infected B cells. As somatic reversion correlated with EBV infection, we propose that the virus exerts a selective pressure on the reverted cells, resulting in their expansion in vivo and host protection against ongoing infection. PMID:22493517

"My Grandfather Slammed the Door in Winston Churchill's Face!" Using Family History to Provoke Rigorous Enquiry

ERIC Educational Resources Information Center

Barrett, Paul

2011-01-01

The idea of using "little stories" to illuminate the "big pictures" of the past was creatively explored in "Teaching History 107," which offered teachers a wealth of detailed vignettes with which to kindle young people's interest and illuminate major historical events. Paul Barrett builds on the ideas explored in that…

Comparison of Selection Procedures and Validation of Criterion Used in Selection of Significant Control Variates of a Simulation Model

DTIC Science & Technology

1990-03-01

and M.H. Knuter. Applied Linear Regression Models. Homewood IL: Richard D. Erwin Inc., 1983. Pritsker, A. Alan B. Introduction to Simulation and SLAM...Control Variates in Simulation," European Journal of Operational Research, 42: (1989). Neter, J., W. Wasserman, and M.H. Xnuter. Applied Linear Regression Models

Getting Slammed: White Depictions of Race Discussions as Arenas of Violence

ERIC Educational Resources Information Center

DiAngelo, Robin; Sensoy, Özlem

2014-01-01

For many educators who lead cross-racial discussions, creating "safe" spaces in which students can express their views is a familiar goal. Yet what constitutes safety is rarely defined or contextualized. In the absence of this contextualization, the goal of safety is most often driven by White participants who complain that they are (or…

78 FR 73173 - Endangered and Threatened Wildlife and Plants; Listing the Straight-Horned Markhor as Threatened...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

... Club, African Safari Club of Florida, The Conklin Foundation, Grand Slam Club/Ovis, Wild Sheep... had reached a critical level, estimated at fewer than 200 (Ahmed et al. 2001, p. 4; Johnson 1994b, p... the markhor at the species level (Capra falconeri) was transferred from CITES Appendix II to Appendix...

40 CFR 58.20 - Special purpose monitors (SPM).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Administrator will not base a NAAQS violation determination for the PM2.5 or ozone NAAQS solely on data from the... discontinuation of the monitor as a SLAMS site. (b) Any SPM data collected by an air monitoring agency using a... monitoring agency's data objectives are inconsistent with those requirements. Data collected at an SPM using...

Dynamo: A Model Transition Framework for Dynamic Stability Control and Body Mass Manipulation

DTIC Science & Technology

2011-11-01

driving at high speed, and you turn the steering wheel hard to the right and slam on the brakes, then you will end up in the oversteer regime. At the...sensors (GPS, IMU, LIDAR ) for vehicle control. Figure 17: Dynamo high-speed small UGV hardware platform We will perform experiments to measure the MTC

An Ex-Soldier Finds a New Mission

ERIC Educational Resources Information Center

Sander, Libby

2012-01-01

Matthew Reilly's roundabout journey to college took a painful, decisive turn after a nighttime crash in Iraq. In 2008, six months into his first combat tour with the Army, Mr. Reilly and nine soldiers from his platoon were pursuing an insurgent when their armored fighting vehicle slammed into a roadblock. It was 2 o'clock in the morning, and fresh…

40 CFR Appendix A to Part 58 - Quality Assurance Requirements for SLAMS, SPMs and PSD Air Monitoring

Code of Federal Regulations, 2014 CFR

2014-07-01

... monitor. 3.3.4.4Pb Performance Evaluation Program (PEP) Procedures. Each year, one performance evaluation... Information 2. Quality System Requirements 3. Measurement Quality Check Requirements 4. Calculations for Data... 10 of this appendix) and at a national level in references 1, 2, and 3 of this appendix. 1...

40 CFR Appendix A to Part 58 - Quality Assurance Requirements for SLAMS, SPMs and PSD Air Monitoring

Code of Federal Regulations, 2013 CFR

2013-07-01

... monitor. 3.3.4.4Pb Performance Evaluation Program (PEP) Procedures. Each year, one performance evaluation... Information 2. Quality System Requirements 3. Measurement Quality Check Requirements 4. Calculations for Data... 10 of this appendix) and at a national level in references 1, 2, and 3 of this appendix. 1...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubart, Philippe; Hautot, Felix; Morichi, Massimo

Good management of dismantling and decontamination (D and D) operations and activities is requiring safety, time saving and perfect radiological knowledge of the contaminated environment as well as optimization for personnel dose and minimization of waste volume. In the same time, Fukushima accident has imposed a stretch to the nuclear measurement operational approach requiring in such emergency situation: fast deployment and intervention, quick analysis and fast scenario definition. AREVA, as return of experience from his activities carried out at Fukushima and D and D sites has developed a novel multi-sensor solution as part of his D and D research, approachmore » and method, a system with real-time 3D photo-realistic spatial radiation distribution cartography of contaminated premises. The system may be hand-held or mounted on a mobile device (robot, drone, e.g). In this paper, we will present our current development based on a SLAM technology (Simultaneous Localization And Mapping) and integrated sensors and detectors allowing simultaneous topographic and radiological (dose rate and/or spectroscopy) data acquisitions. This enabling technology permits 3D gamma activity cartography in real-time. (authors)« less

Remote inspection with multi-copters, radiological sensors and SLAM techniques

NASA Astrophysics Data System (ADS)

Carvalho, Henrique; Vale, Alberto; Marques, Rúben; Ventura, Rodrigo; Brouwer, Yoeri; Gonçalves, Bruno

2018-01-01

Activated material can be found in different scenarios, such as in nuclear reactor facilities or medical facilities (e.g. in positron emission tomography commonly known as PET scanning). In addition, there are unexpected scenarios resulting from possible accidents, or where dangerous material is hidden for terrorism attacks using nuclear weapons. Thus, a technological solution is important to cope with fast and reliable remote inspection. The multi-copter is a common type of Unmanned Aerial Vehicle (UAV) that provides the ability to perform a first radiological inspection in the described scenarios. The paper proposes a solution with a multi-copter equipped with on-board sensors to perform a 3D reconstruction and a radiological mapping of the scenario. A depth camera and a Geiger-Müler counter are the used sensors. The inspection is performed in two steps: i) a 3D reconstruction of the environment and ii) radiation activity inference to localise and quantify sources of radiation. Experimental results were achieved with real 3D data and simulated radiation activity. Experimental tests with real sources of radiation are planned in the next iteration of the work.

Gone with the Wind? Integrity and Hurricane Katrina

ERIC Educational Resources Information Center

Lucas, Frances; Katz, Brit

2011-01-01

Hurricane Katrina slammed into 80 miles of Mississippi shoreline on August 29, 2005. It was the nation's worst natural disaster, a perfect storm. One hundred sixty miles-per-hour winds sent 55-foot-tall waves and a 30-foot wall of water across the shore and miles inland. It displaced 400,000 residents along the coast of the Mississippi, and…

Learning to Control Collisions: The Role of Perceptual Attunement and Action Boundaries

ERIC Educational Resources Information Center

Fajen, Brett R.; Devaney, Michael C.

2006-01-01

The authors investigated the role of perceptual attunement in an emergency braking task in which participants waited until the last possible moment to slam on the brakes. Effects of the size of the approached object and initial speed on the initiation of braking were used to identify the optical variables on which participants relied at various…

Making Hands-On Science Learning Accessible for Students Who Are Blind or Have Low Vision

ERIC Educational Resources Information Center

Supalo, Cary; Isaacson, Mick D.; Lombardi, Michael V.

2014-01-01

The 2011 National Federation of the Blind Youth Slam event at Towson University enabled a large group of blind youth to participate in a five day long science, technology, engineering, and mathematics (STEM) academy. Enrichment experiences such as this one may generate interest in STEM subjects for students with visual impairments. For decades,…

Let's Put Demography Back into Economics: Population Pyramids in Excel

ERIC Educational Resources Information Center

Barreto, Humberto

2018-01-01

The economics curriculum today does not emphasize the study of population. This needs to change immediately because we are in the midst of another demographic sea change, slamming on the brakes right after a rapid acceleration during the last half of the twentieth century. Instead of glibly tossing a dependency ratio onto a slide, this article…

Illuminating Encounters with "Emotional" Students: How to Respond in an Educative Way

ERIC Educational Resources Information Center

West, Amanda

2014-01-01

When educators label as "emotional" the girl crying in the bathroom or the boy who just slammed his locker shut, they risk assuming that only overt displays qualify as emotional and therefore necessitate attention. The fact is that whether a student outwardly displays emotion or not, he or she is emotional, and the teacher has a…

"How'd You Come out?": In New Orleans, the Library Serves Despite Struggles, and Help Emerges

ERIC Educational Resources Information Center

Oder, Norman

2006-01-01

In this article, the author describes how the New Orleans Public Library (NOPL) struggled with a fraction of its former staff, limited hours, and a massive fundraising challenge after Hurricane Katrina slammed the Gulf Coast on August 29, 2005. While previously 171 people staffed locations, only 40 employees plus a smaller--and shifting--cadre of…

Connecting the Disconnected: Scholar Activists and Education Reform in Post-Katrina New Orleans

ERIC Educational Resources Information Center

Cook, Daniella Ann

2014-01-01

When Hurricane Katrina slammed into New Orleans on August 29, 2005, the failure of the levees resulted in the largest single human-made disaster in the United States. In addition to the physical devastation of the city, the landscape of public schools in New Orleans was permanently altered, as was the national dialogue about school reform in the…

Quest Trial Q348: Evaluation of WaMoS II Data

DTIC Science & Technology

2013-04-01

and slam warning.” Quest Sea Trial Q348 page 7 “In July of 2011, as part of the 11gi project, DRDC acquired and installed a new WaMoS...Fourier series expansion was originally implemented to compare WaMoS II data to reference data of an airborne LIDAR scanner, which yielded very good

The Origins of the Transformation of the Defense Language Program

ERIC Educational Resources Information Center

Raugh, Harold E., Jr.

2006-01-01

The horrific events of 11 September 2001, when four hijacked jetliners crashed into and collapsed the twin-towered World Trade Center in New York, slammed into the Pentagon, and nose-dived into a field in rural Pennsylvania (ostensibly on a mission to destroy the U.S. Capitol or the White House), have been indelibly etched into the nation's…

Mary Catherine and Me: Building Cross-Cultural Relationships in "Post-Racial" America

ERIC Educational Resources Information Center

Bruno, Holly Elissa

2009-01-01

In 1963, President Obama's parents could not have married legally in a number of states. Mary Catherine and the author graduated from Corning Free Academy in Corning, New York, in June 1963. The lessons they learned were wrenching: "Someone is going to get hurt." Doors that opened for the author slammed in Mary Catherine's face. Holding Mary…

Compassion Is Dissent: The Institute for the Art and Practice of Dissent at Home

ERIC Educational Resources Information Center

Research in Drama Education, 2017

2017-01-01

Following the devastating result of the May 2015 general election in the UK, the Institute for the Art and Practice of Dissent at Home organised "Compassion is dissent: Manifesto Slam." It put out an open call for participants, asking them to bring a three-minute manifesto as means of admission to the event. Here, the Institute showcases…

Swinging Open or Slamming Shut? The Implications of China's Open-Door Policy for Women, Educational Choice and Work

ERIC Educational Resources Information Center

Turner, Yvonne

2006-01-01

This paper explores the link between international tertiary education and evolving attitudes about women and work in China. The paper reviews literature about gender and education in China, commenting on the late-twentieth-century post-reform environment. It goes on to present illustrative primary research material from two studies carried out…

Remembering Kate and Kathy: Two Passionate Youth Librarians Leave Behind a Lasting Legacy

ERIC Educational Resources Information Center

Smith, Vicky

2009-01-01

For children's book lovers, the world was infinitely glorious on Monday, January 26, 2009, as the winners of the American Library Association's (ALA) awards were announced at the midwinter meeting in Denver. But two days later, a drunk driver slammed into a taxicab, killing two children's librarians as they were on their way to the Denver…

3D indoor modeling using a hand-held embedded system with multiple laser range scanners

NASA Astrophysics Data System (ADS)

Hu, Shaoxing; Wang, Duhu; Xu, Shike

2016-10-01

Accurate three-dimensional perception is a key technology for many engineering applications, including mobile mapping, obstacle detection and virtual reality. In this article, we present a hand-held embedded system designed for constructing 3D representation of structured indoor environments. Different from traditional vehicle-borne mobile mapping methods, the system presented here is capable of efficiently acquiring 3D data while an operator carrying the device traverses through the site. It consists of a simultaneous localization and mapping(SLAM) module, a 3D attitude estimate module and a point cloud processing module. The SLAM is based on a scan matching approach using a modern LIDAR system, and the 3D attitude estimate is generated by a navigation filter using inertial sensors. The hardware comprises three 2D time-flight laser range finders and an inertial measurement unit(IMU). All the sensors are rigidly mounted on a body frame. The algorithms are developed on the frame of robot operating system(ROS). The 3D model is constructed using the point cloud library(PCL). Multiple datasets have shown robust performance of the presented system in indoor scenarios.

A pose estimation method for unmanned ground vehicles in GPS denied environments

NASA Astrophysics Data System (ADS)

Tamjidi, Amirhossein; Ye, Cang

2012-06-01

This paper presents a pose estimation method based on the 1-Point RANSAC EKF (Extended Kalman Filter) framework. The method fuses the depth data from a LIDAR and the visual data from a monocular camera to estimate the pose of a Unmanned Ground Vehicle (UGV) in a GPS denied environment. Its estimation framework continuy updates the vehicle's 6D pose state and temporary estimates of the extracted visual features' 3D positions. In contrast to the conventional EKF-SLAM (Simultaneous Localization And Mapping) frameworks, the proposed method discards feature estimates from the extended state vector once they are no longer observed for several steps. As a result, the extended state vector always maintains a reasonable size that is suitable for online calculation. The fusion of laser and visual data is performed both in the feature initialization part of the EKF-SLAM process and in the motion prediction stage. A RANSAC pose calculation procedure is devised to produce pose estimate for the motion model. The proposed method has been successfully tested on the Ford campus's LIDAR-Vision dataset. The results are compared with the ground truth data of the dataset and the estimation error is ~1.9% of the path length.

[Cathinones use in Paris].

PubMed

Batisse, A; Grégoire, M; Marillier, M; Fortias, M; Djezzar, S

2016-08-01

The pattern of recreational drug use has changed over the last decade and now includes a multitude of substances sold as "research chemicals" or new psychoactive substances, "NPS". In France, synthetic cathinones emerged in 2008 (while first mentioned by the French police force in 2007 first alerts among users appeared in 2008) and have grown to be popular drugs of abuse. Under the Official Journal dated 11th June 2010, only mephedrone has been listed as narcotics but "designer drugs" have synthesized new substitute cathinones in order to avoid anti-drug laws. However, since July 2012, in France, all synthetic drugs from the cathinones family have been banned and listed as narcotics following the example of United Kingdom. Despite their recent classification and inclusion on narcotic list, they are readily available on Internet and used widely. Paris Addictovigilance Centre observed a signal of derivate cathinones abuse (21 cases over a two-year period). Paris Addictovigilance Centre and Marmottan Hospital wanted to describe the use of cathinones in the Paris area and alert the health care community about the abuse identification and risk assessment problems of these compounds. After a review of derivated cathinone's chemical structure, pharmacology and toxicology, this article seeks to provide patricians with a clinical description and treatment's modality. Most users of synthetic cathinones will experience euphoria, increased energy, talkativeness, openness and increased sexual arousal. Signs and symptoms of toxicity are consistent with a sympathomimetic toxidrome. The main reasons for care access are psychiatric (hallucinations, psychotic symptoms, agitation) and addiction disorders. Somatic complications were described with various patterns of symptoms such as headache, tachycardia, confusional states, rhabdomyolysis with renal failure or serotonin syndrome. The most important fact is the apparition of the "slam" phenomenon among men who have sex with men (MSM). The "slam" is a compound of three characteristic elements: injection, sexual party and psychostimulant drug. According to users, "slam" is convenient for group sex and is used it to put them into a good mood and a disinhibition state. These compounds cause fast dependence syndrome with strong craving and prolonged psychiatric symptoms and increase infectious risk (HIV, VHC, VHB…). The cathinones family is not detected in conventional urine drug screenings. We point out the lack of confirmatory analytic testing data which remains the only way to determine the actual etiology of the clinical effects observed since drug users do not always know exactly what they took. These substances can be identified by special analyses using gas chromatography or liquid chromatography and mass spectroscopy technology. This injection drug is used in order to increase sexual desire, delay orgasm and decrease sexual inhibition and is prevalent in many studies on MSM samples. Cathinones would popularize the "slam". Harm reduction policy requires specific MSM interventions on both sexual and drug addiction networks. Copyright © 2015 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

Neuropsychiatric lupus: the prevalence and autoantibody associations depend on the definition: results from the 1000 faces of lupus cohort.

PubMed

Borowoy, Alan M; Pope, Janet E; Silverman, Earl; Fortin, Paul R; Pineau, Christian; Smith, C Douglas; Arbillaga, Hector; Gladman, Dafna; Urowitz, Murray; Zummer, Michel; Hudson, Marie; Tucker, Lori; Peschken, Christine

2012-10-01

The (ever) prevalence of neuropsychiatric systemic lupus erythematosus (NPSLE) can vary widely depending on the definition used. We determined the prevalence of NPSLE in 1000 Faces of Lupus, a large multicenter Canadian cohort. Adults enrolled at 10 sites who satisfied the American College of Rheumatology (ACR) classification for systemic lupus erythematosus (SLE) were included. NPSLE was defined as (i) NPSLE by ACR classification criteria (seizures or psychosis), (ii) ACR, SLEDAI (seizure, psychosis, organic brain syndrome, cranial nerve disorder, headache, and cerebrovascular accident (CVA)), SLAM (CVA, seizure, cortical dysfunction, and headache), and SLICC (cognitive impairment, psychosis, seizures, CVA, cranial or peripheral neuropathy, and transverse myelitis) with and (iii) without minor nonspecific NPSLE manifestations (including mild depression, mild cognitive impairment, and electromyogram-negative neuropathies), and (iv) by ACR and SLEDAI neuropsychiatric (NP) indexes alone. Factors associated with NPSLE were explored using regression models. Cohort size was 1253, with mean disease 12 ± 10 years, mean age 41 ± 16 years, and 86% female. Subgroup size was dependent on the specific definition of NPSLE. Prevalence of NPSLE was 6.4% in group (i), n = 1253 (n = 80); 38.6% in group (ii), n = 681(n = 263); 28.7% in group (iii), n = 586 (n = 168); and 10.2% in group (iv), n = 1125 (n = 115). In univariate analysis, Aboriginals had a nearly 2-fold increase in frequency of NPSLE in all groups. Education level and income were not associated with NPSLE (P = 0.32 and 0.03, respectively). As well, number of ACR criteria, SLAM, age at diagnosis, disease duration, and gender were not associated with NPSLE. Anti-Ro was significantly associated in groups (i) and (iv) and antiphospholipid antibodies (aPL) were increased in groups (i), (ii), and (iii); however, this lost significance when thromboembolic events were excluded from SLICC, SLEDAI, and SLAM indexes. In group (iv), absence of anti-Sm was significant. In multivariate analysis, anti-Ro and aPL (i) and anti-Ro+ and lack of anti-Sm (iv) were significant. NPSLE was not increased in those with +anti-DNA, La, or ribonucleoprotein (RNP), lupus anticoagulant (LAC), or anticardiolipin (aCL) antibody. The prevalence and factors associated with NPSLE varied depending on the definition used, was highest in Aboriginals, and may be higher if +anti-Ro or aPL are present. SLAM and SLICC include mild subjective disease manifestations, which contributed to a 10% higher prevalence of NPSLE compared to a more strict definition. NPSLE may be less in this database than other publications as its overall prevalence may be decreasing, or because of selection bias inherent to those who enter an observational cohort. NPSLE was associated with aPL and often anti-Ro and varied by ethnicity. Copyright © 2012 Elsevier Inc. All rights reserved.

[Liver and spleen biometrics in childhood-onset systemic lupus erythematosus patients].

PubMed

Guariento, Andressa; Silva, Marco Felipe C; Tassetano, Priscilla S F; Rocha, Sílvia Maria S; Campos, Lúcia M A; Valente, Marcelo; Silva, Clovis A

2015-01-01

To evaluate liver and spleen dimensions in childhood-onset systemic lupus erythematosus (c-SLE) patients and healthy controls. 30 c-SLE patients and 30 healthy control volunteers underwent abdominal ultrasound. The following two liver measurements were performed in left hepatic lobe: craniocaudal and anteroposterior and three in right hepatic lobe (RHL): posterior craniocaudal (PCC-RHL), anterior craniocaudal and anteroposterior. Three spleen dimension measurements were also evaluated: longitudinal, transverse and anteroposterior. Demographic, clinical and laboratorial data, SLEDAI-2K, ECLAM, SLAM and treatment were assessed. Mean current age was similar in c-SLE and controls (170.31 ± 27.81 vs. 164.15 ± 39.25 months; p = 0.486). The mean of PCC-RHL dimension was significantly higher in c-SLE compared to controls (13.30 ± 1.85 vs. 12.52 ± 0.93, p = 0.044). There were no differences between the other hepatic biometrics and splenic parameters (p > 0.05). Further analysis in c-SLE patients according to PCC-RHL dimension ≥ 13.3cm versus < 13.3 cm showed that the median of SLEDAI-2K [8(0-18) vs. 2(0-8), p=0.004], ECLAM [4(0-9) vs. 2(0-5), p = 0.019] and SLAM [5(1-13) vs. 2(0-14), p = 0.016] were significantly higher in patients with higher PCC-RHL dimension, likewise the frequencie of nephritis (77% vs. 29%, p = 0.010). Liver enzymes were similar in both groups (p > 0.05). Positive correlation was observed between SLEDAI-2K and PCC-RHL (p = 0.001, r = +0.595). Negative correlation was evidenced between disease duration and longitudinal dimension of spleen (p = 0.031, r = -0.394). Our data raises the possibility that disease activity could lead to a subclinical and localized hepatomegaly during the disease course. Long disease duration resulted to spleen atrophy in c-SLE patients. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

Developing a new model for patient recruitment in mental health services: a cohort study using Electronic Health Records

PubMed Central

Callard, Felicity; Broadbent, Matthew; Denis, Mike; Hotopf, Matthew; Soncul, Murat; Wykes, Til; Lovestone, Simon; Stewart, Robert

2014-01-01

Objectives To develop a new model for patient recruitment that harnessed the full potential of Electronic Health Records (EHRs). Gaining access to potential participants’ health records to assess their eligibility for studies and allow an approach about participation (‘consent for contact’) is ethically, legally and technically challenging, given that medical data are usually restricted to the patient's clinical team. The research objective was to design a model for identification and recruitment to overcome some of these challenges as well as reduce the burdensome (and/or time consuming) gatekeeper role of clinicians in determining who is appropriate or not to participate in clinical research. Setting Large secondary mental health services context, UK. Participants 2106 patients approached for ‘consent for contact’. All patients in different services within the mental health trust are gradually and systematically being approached by a member of the clinical care team using the ‘consent for contact’ model. There are no exclusion criteria. Primary and secondary outcome measures Provision of ‘consent for contact’. Results A new model (the South London and Maudsley NHS Trust Consent for Contact model (SLaM C4C)) for gaining patients’ consent to contact them about research possibilities, which is built around a de-identified EHR database. The model allows researchers to contact potential participants directly. Of 2106 patients approached by 25 October 2013, nearly 3 of every 4 gave consent for contact (1560 patients; 74.1%). Conclusions The SLaM C4C model offers an effective way of expediting recruitment into health research through using EHRs. It reduces the gatekeeper function of clinicians; gives patients greater autonomy in decisions to participate in research; and accelerates the development of a culture of active research participation. More research is needed to assess how many of those giving consent for contact subsequently consent to participate in particular research studies. PMID:25468503

Good Teachers (the Movie You Will Never See)

ERIC Educational Resources Information Center

Gillard, Colleen

2012-01-01

It began with a trip to the cinema to see Cameron Diaz in her new comedy, "Bad Teacher." It was a bad choice. Not a great flick, but as a parody of bad employees, in terms of things that can get one fired--drugs, alcohol , cheating, foul language, inappropriate sexual behavior--Diaz slams pedal to the metal. She nips out of airline booze bottles…

Help Kids Stay Safe on the Playground | DoDLive

Science.gov Websites

. One day, as I zoomed past another kid on this imaginary rink, I lost my balance, hit the ice face -first and shot like a hockey puck across its slippery surface before slamming into a chain link fence one else knows I have a fake front tooth, but I am reminded every day of that playground injury many

Quashing ownership: health reform law bans new physician-owned hospitals.

PubMed

Ortolon, Ken

2010-08-01

With nearly 70 Texas hospitals with some type of physician investment, the state is a national leader in the physician-owned hospital industry. And, members of that industry say it has been good for patients. But the health system reform law Congress passed earlier this year slams the door on new physician-owned hospitals by prohibiting them from obtaining a Medicare provider number.

Considering species richness and rarity when selecting optimal survey traps: comparison of semiochecmial baited flight intercept traps for Cerambycidae in eastern North America

Treesearch

Kevin J. Dodds; Jeremy D. Allison; Daniel R. Miller; Ryan P. Hanavan; Jon Sweeney

2015-01-01

1.) We compared standard multiple-funnel, modified multiple-funnel, intercept panel and canopy malaise (SLAM) traps with top and bottom collecting cups for their effectiveness (species richness, rarity, abundance) at capturing Cerambycidae in eastern North America. 2.) Experiments were conducted in New York, Louisiana, Massachusetts and Georgia in 2011 and 2012. A...

Intelligent Behavioral Action Aiding for Improved Autonomous Image Navigation

DTIC Science & Technology

2012-09-13

odometry, SICK laser scanning unit ( Lidar ), Inertial Measurement Unit (IMU) and ultrasonic distance measurement system (Figure 32). The Lidar , IMU...2010, July) GPS world. [Online]. http://www.gpsworld.com/tech-talk- blog/gnss-independent-navigation-solution-using-integrated- lidar -data-11378 [4...Milford, David McKinnon, Michael Warren, Gordon Wyeth, and Ben Upcroft, "Feature-based Visual Odometry and Featureless Place Recognition for SLAM in

Occupancy Grid Map Merging Using Feature Maps

DTIC Science & Technology

2010-11-01

each robot begins exploring at different starting points, once two robots can communicate, they send their odometry data, LIDAR observations, and maps...robots [11]. Moreover, it is relevant to mention that significant success has been achieved in solving SLAM problems when using hybrid maps [12...represents the environment by parametric features. Our method is capable of representing a LIDAR scanned environment map in a parametric fashion. In general

Handheld Synthetic Array Final Report, Part A

DTIC Science & Technology

2014-12-01

Measurement Unit 4/143 IEEE Institute of Electrical and Electronics Engineers KF Kalman Filter KL Kullback - Leibler LAMBDA Least-squares... testing the algorithms for the LOS AN wireless beamforming. Given a good set of feature points, the ego-motion is sufficiently accurate to... of little value to the overall SLAM and the RSS observables are used instead. While individual RSS measurements are low in information value, the

SLAM: A multi-agency pilot project to SL.ow A.sh M.ortality caused by emerald ash borer in outlier sites

Treesearch

Therese M. Poland; Deborah G. McCullough

2010-01-01

Since its discovery in southeast Michigan in 2002, the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has continued to spread and kill ash (Fraxinus) trees at an alarming rate. As of February 2010, EAB has killed tens of millions of ash trees in Michigan, at least 12 additional U.S. states, and the...

40 CFR Appendix A to Part 58 - Quality Assurance Requirements for SLAMS, SPMs and PSD Air Monitoring

Code of Federal Regulations, 2011 CFR

2011-07-01

... in section 4.3.1 of this appendix. 3.2.7PM2.5 Performance Evaluation Program (PEP) Procedures. The... evaluation audit means that both the primary monitor and PEP audit concentrations are valid and above 3 µg/m3... Evaluation Program (PEP) Procedures. Each year, one performance evaluation audit, as described in section 3.2...

40 CFR Appendix A to Part 58 - Quality Assurance Requirements for SLAMS, SPMs and PSD Air Monitoring

Code of Federal Regulations, 2012 CFR

2012-07-01

... in section 4.3.1 of this appendix. 3.2.7PM2.5 Performance Evaluation Program (PEP) Procedures. The... evaluation audit means that both the primary monitor and PEP audit concentrations are valid and above 3 µg/m3... Evaluation Program (PEP) Procedures. Each year, one performance evaluation audit, as described in section 3.2...

Using Adaptive Tools and Techniques to Teach a Class of Students Who Are Blind or Low-Vision

ERIC Educational Resources Information Center

Supalo, Cary A.; Mallouk, Thomas E.; Amorosi, Christeallia; Lanouette, James; Wohlers, H. David; McEnnis, Kathleen

2009-01-01

A brief overview of the 2007 National Federation of the Blind-Jernigan Institute Youth Slam Chemistry Track, a course of study within a science camp that provided firsthand experimental experience to 200 students who are blind and low-vision, is given. For many of these students, this was their first hands-on experience with laboratory chemistry.…

A Framework for the Development of Scalable Heterogeneous Robot Teams with Dynamically Distributed Processing

NASA Astrophysics Data System (ADS)

Martin, Adrian

As the applications of mobile robotics evolve it has become increasingly less practical for researchers to design custom hardware and control systems for each problem. This research presents a new approach to control system design that looks beyond end-of-lifecycle performance and considers control system structure, flexibility, and extensibility. Toward these ends the Control ad libitum philosophy is proposed, stating that to make significant progress in the real-world application of mobile robot teams the control system must be structured such that teams can be formed in real-time from diverse components. The Control ad libitum philosophy was applied to the design of the HAA (Host, Avatar, Agent) architecture: a modular hierarchical framework built with provably correct distributed algorithms. A control system for exploration and mapping, search and deploy, and foraging was developed to evaluate the architecture in three sets of hardware-in-the-loop experiments. First, the basic functionality of the HAA architecture was studied, specifically the ability to: a) dynamically form the control system, b) dynamically form the robot team, c) dynamically form the processing network, and d) handle heterogeneous teams. Secondly, the real-time performance of the distributed algorithms was tested, and proved effective for the moderate sized systems tested. Furthermore, the distributed Just-in-time Cooperative Simultaneous Localization and Mapping (JC-SLAM) algorithm demonstrated accuracy equal to or better than traditional approaches in resource starved scenarios, while reducing exploration time significantly. The JC-SLAM strategies are also suitable for integration into many existing particle filter SLAM approaches, complementing their unique optimizations. Thirdly, the control system was subjected to concurrent software and hardware failures in a series of increasingly complex experiments. Even with unrealistically high rates of failure the control system was able to successfully complete its tasks. The HAA implementation designed following the Control ad libitum philosophy proved to be capable of dynamic team formation and extremely robust against both hardware and software failure; and, due to the modularity of the system there is significant potential for reuse of assets and future extensibility. One future goal is to make the source code publically available and establish a forum for the development and exchange of new agents.

Gosses Bluff

NASA Image and Video Library

2017-12-08

August 14th, 2002: Description: 142 million years ago, an asteroid or comet slammed into what is now the Missionary Plains in Australia’s Northern Territory, forming a crater 24 kilometers in diameter and 5 kilometers deep. Today, like a bull’s eye, the circular ring of hills that defines Gosses Bluff stands as a stark reminder of the event. Source: Landsat 7 To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/

Smashing Protons to Smithereens

ScienceCinema

Pleier, Marc-André

2018-01-05

Pleier discusses the extraordinary research taking place at the Large Hadron Collider (LHC) — the world’s newest, biggest, and highest energy particle accelerator located at CERN. Pleier is one of hundreds of researchers from around the world working on ATLAS, a seven-story particle detector positioned at a point where the LHC’s oppositely circulating beams of protons slam into one another head-on.

Magician Simulator: A Realistic Simulator for Heterogenous Teams of Autonomous Robots. MAGIC 2010 Challenge

DTIC Science & Technology

2011-02-07

Sensor UGVs (SUGV) or Disruptor UGVs, depending on their payload. The SUGVs included vision, GPS/IMU, and LIDAR systems for identifying and tracking...employed by all the MAGICian research groups. Objects of interest were tracked using standard LIDAR and Computer Vision template-based feature...tracking approaches. Mapping was solved through Multi-Agent particle-filter based Simultaneous Locali- zation and Mapping ( SLAM ). Our system contains

Magician Simulator. A Realistic Simulator for Heterogenous Teams of Autonomous Robots

DTIC Science & Technology

2011-01-18

IMU, and LIDAR systems for identifying and tracking mobile OOI at long range (>20m), providing early warnings and allowing neutralization from a... LIDAR and Computer Vision template-based feature tracking approaches. Mapping was solved through Multi-Agent particle-filter based Simultaneous...Locali- zation and Mapping ( SLAM ). Our system contains two maps, a physical map and an influence map (location of hostile OOI, explored and unexplored

University of Pennsylvania MAGIC 2010 Final Report

DTIC Science & Technology

2011-01-10

and mapping ( SLAM ) techniques are employed to build a local map of the environment surrounding the robot. Readings from the two complementary LIDAR sen...IMU, LIDAR , Cameras Localization Disrupter UGV Local Navigation Sensors: GPS, IMU, LIDAR , Cameras Laser Control Localization Task Planner Strategy/Plan...various components shown in Figure 2. This is comprised of the following subsystems: • Sensor UGV: Mobile UGVs with LIDAR and camera sensors, GPS, and

Cloud-Based Perception and Control of Sensor Nets and Robot Swarms

DTIC Science & Technology

2016-04-01

distributed stream processing framework provides the necessary API and infrastructure to develop and execute such applications in a cluster of computation...streaming DDDAS applications based on challenges they present to the backend Cloud control system. Figure 2 Parallel SLAM Application 3 1) Set of...the art deep learning- based object detectors can recognize among hundreds of object classes and this capability would be very useful for mobile

Long-Term Simultaneous Localization and Mapping in Dynamic Environments

DTIC Science & Technology

2015-01-01

core competencies required for autonomous mobile robotics is the ability to use sensors to perceive the environment. From this noisy sensor data, the...and mapping (SLAM), is a prerequisite for almost all higher-level autonomous behavior in mobile robotics. By associating the robot???s sensory...distributed stochastic neighbor embedding x ABSTRACT One of the core competencies required for autonomous mobile robotics is the ability to use sensors

Mining and Exploitation of Rare Earth Elements in Africa as an Engagement Strategy in US Africa Command

DTIC Science & Technology

2011-06-17

rechargeable batteries, cell phones, catalytic converters, fluorescent lights, hybrid vehicle batteries, and other pollution control devices.21 Figure...79 Lee Yong-tim, “South China Villagers Slam Pollution from Rare Earth Mine,” February 22, 2008, http://www.rfa.org/english...writing and implementing new environmental standards. “The rules will limit pollutants allowed in waste water and emissions of radioactive elements

Robust Parallel Motion Estimation and Mapping with Stereo Cameras in Underground Infrastructure

NASA Astrophysics Data System (ADS)

Liu, Chun; Li, Zhengning; Zhou, Yuan

2016-06-01

Presently, we developed a novel robust motion estimation method for localization and mapping in underground infrastructure using a pre-calibrated rigid stereo camera rig. Localization and mapping in underground infrastructure is important to safety. Yet it's also nontrivial since most underground infrastructures have poor lighting condition and featureless structure. Overcoming these difficulties, we discovered that parallel system is more efficient than the EKF-based SLAM approach since parallel system divides motion estimation and 3D mapping tasks into separate threads, eliminating data-association problem which is quite an issue in SLAM. Moreover, the motion estimation thread takes the advantage of state-of-art robust visual odometry algorithm which is highly functional under low illumination and provides accurate pose information. We designed and built an unmanned vehicle and used the vehicle to collect a dataset in an underground garage. The parallel system was evaluated by the actual dataset. Motion estimation results indicated a relative position error of 0.3%, and 3D mapping results showed a mean position error of 13cm. Off-line process reduced position error to 2cm. Performance evaluation by actual dataset showed that our system is capable of robust motion estimation and accurate 3D mapping in poor illumination and featureless underground environment.

Some personal and historical notes on the utility of "deep-etch" electron microscopy for making cell structure/function correlations.

PubMed

Heuser, John E

2014-11-01

This brief essay talks up the advantages of metal replicas for electron microscopy and explains why they are still the best way to image frozen cells in the electron microscope. Then it explains our approach to freezing, namely the Van Harreveld trick of "slamming" living cells onto a supercold block of metal sprayed with liquid helium at -269ºC, and further talks up this slamming over the alternative of high-pressure freezing, which is much trickier but enjoys greater favor at the moment. This leads me to bemoan the fact that there are not more young investigators today who want to get their hands on electron microscopes and use our approach to get the most "true to life" views of cells out of them with a minimum of hassle. Finally, it ends with a few perspectives on my own career and concludes that, personally, I'm permanently stuck with the view of the "founding fathers" that cell ultrastructure will ultimately display and explain all of cell function, or as Palade said in his Nobel lecture,electron micrographs are "irresistible and half transparent … their meaning buried under only a few years of work," and "reasonable working hypotheses are already suggested by the ultrastructural organization itself." © 2014 Heuser.

LiDAR Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments

PubMed Central

Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha

2015-01-01

A new scan that matches an aided Inertial Navigation System (INS) with a low-cost LiDAR is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies—INS and LiDAR SLAM—into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform—NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment. PMID:26184206

Extension of an iterative closest point algorithm for simultaneous localization and mapping in corridor environments

NASA Astrophysics Data System (ADS)

Yue, Haosong; Chen, Weihai; Wu, Xingming; Wang, Jianhua

2016-03-01

Three-dimensional (3-D) simultaneous localization and mapping (SLAM) is a crucial technique for intelligent robots to navigate autonomously and execute complex tasks. It can also be applied to shape measurement, reverse engineering, and many other scientific or engineering fields. A widespread SLAM algorithm, named KinectFusion, performs well in environments with complex shapes. However, it cannot handle translation uncertainties well in highly structured scenes. This paper improves the KinectFusion algorithm and makes it competent in both structured and unstructured environments. 3-D line features are first extracted according to both color and depth data captured by Kinect sensor. Then the lines in the current data frame are matched with the lines extracted from the entire constructed world model. Finally, we fuse the distance errors of these line-pairs into the standard KinectFusion framework and estimate sensor poses using an iterative closest point-based algorithm. Comparative experiments with the KinectFusion algorithm and one state-of-the-art method in a corridor scene have been done. The experimental results demonstrate that after our improvement, the KinectFusion algorithm can also be applied to structured environments and has higher accuracy. Experiments on two open access datasets further validated our improvements.

Estimation of Visual Maps with a Robot Network Equipped with Vision Sensors

PubMed Central

Gil, Arturo; Reinoso, Óscar; Ballesta, Mónica; Juliá, Miguel; Payá, Luis

2010-01-01

In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM) problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment. PMID:22399930

Estimation of visual maps with a robot network equipped with vision sensors.

PubMed

Gil, Arturo; Reinoso, Óscar; Ballesta, Mónica; Juliá, Miguel; Payá, Luis

2010-01-01

In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM) problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

Open Pit Mine 3d Mapping by Tls and Digital Photogrammetry: 3d Model Update Thanks to a Slam Based Approach

NASA Astrophysics Data System (ADS)

Vassena, G.; Clerici, A.

2018-05-01

The state of the art of 3D surveying technologies, if correctly applied, allows to obtain 3D coloured models of large open pit mines using different technologies as terrestrial laser scanner (TLS), with images, combined with UAV based digital photogrammetry. GNSS and/or total station are also currently used to geo reference the model. The University of Brescia has been realised a project to map in 3D an open pit mine located in Botticino, a famous location of marble extraction close to Brescia in North Italy. Terrestrial Laser Scanner 3D point clouds combined with RGB images and digital photogrammetry from UAV have been used to map a large part of the cave. By rigorous and well know procedures a 3D point cloud and mesh model have been obtained using an easy and rigorous approach. After the description of the combined mapping process, the paper describes the innovative process proposed for the daily/weekly update of the model itself. To realize this task a SLAM technology approach is described, using an innovative approach based on an innovative instrument capable to run an automatic localization process and real time on the field change detection analysis.

Topological visual mapping in robotics.

PubMed

Romero, Anna; Cazorla, Miguel

2012-08-01

A key problem in robotics is the construction of a map from its environment. This map could be used in different tasks, like localization, recognition, obstacle avoidance, etc. Besides, the simultaneous location and mapping (SLAM) problem has had a lot of interest in the robotics community. This paper presents a new method for visual mapping, using topological instead of metric information. For that purpose, we propose prior image segmentation into regions in order to group the extracted invariant features in a graph so that each graph defines a single region of the image. Although others methods have been proposed for visual SLAM, our method is complete, in the sense that it makes all the process: it presents a new method for image matching; it defines a way to build the topological map; and it also defines a matching criterion for loop-closing. The matching process will take into account visual features and their structure using the graph transformation matching (GTM) algorithm, which allows us to process the matching and to remove out the outliers. Then, using this image comparison method, we propose an algorithm for constructing topological maps. During the experimentation phase, we will test the robustness of the method and its ability constructing topological maps. We have also introduced new hysteresis behavior in order to solve some problems found building the graph.

A novel sensor platform for the rapid hydraulic characterisation of freshwater ecosystems

NASA Astrophysics Data System (ADS)

Kriechbaumer, Thomas; Blackburn, Kim; Breckon, Toby; Gill, Andrew; Everard, Nick; Wright, Ros; Rivas Casado, Monica

2014-05-01

The spatially explicit quantification of hydraulic features provides valuable information for the physical habitat assessment of freshwater ecosystems. Collection of data on water velocities and depths using in-situ current meters or acoustic sensors on tethered boats is time-consuming and requires good site accessibility. Moreover, on smaller rivers precise spatial data referencing can be challenging, as river bank vegetation can block sky view to navigation satellites over a considerable proportion of the water surface. This paper describes the development and testing of a new small sized remote control sensor platform and a novel approach to spatial data referencing based on computer vision to enable the rapid hydraulic characterisation of habitats in small rivers. It highlights the manifold opportunities that recent achievements in the disciplines of computer science and electronics can create for the environmental sciences. The platform carries an acoustic Doppler current profiler (ADCP) to rapidly collect large amounts of data on water velocities and river depths, from which the spatial and temporal water velocity distributions can be derived. The 1.30m long and 0.60m wide platform hull has been designed to enable single person deployment. Platform pitch and roll magnitudes and periods are quantified at a frequency of 512Hz through a low-cost inertial measurement unit on board, allowing the quantification of the errors that these platform motions can cause in the ADCP data. Jet propulsion and a tail thruster ensure high manoeuvrability, minimum draught operation and greater safety than propellers. An on-board Raspberry Pi computer enables time-synchronised logging of data from a GPS unit, the ADCP and further sensors that may be added to the platform. Real-time serial communication between the Raspberry Pi and the embedded propulsion system control (an Arduino Uno microcontroller) builds the basis for future platform autonomy. This can enable the autonomous implementation of pre-defined data collection strategies. Through field experiments, a set of technologies to position the platform in the river environment has been evaluated. Simultaneous localisation and mapping (SLAM) based on frames from a stereo camera has been identified as a promising alternative to satellite-based platform positioning. In terrestrial environments, SLAM has recently achieved high position accuracies, comparable with those of differential GPS. Software that implements SLAM for the river environment is currently developed. This constitutes the first application of visual SLAM on water and, to the authors' knowledge, its first application in the context of environmental research. Furthermore, platform tracking with a motorised Total Station has been found to be a highly accurate (cm-level) positioning technique despite fast platform movements, as long as line of sight to the tracked object is given. In the near future, the platform will be used to characterise the hydraulic conditions downstream of fish passes in order to rapidly assess the attractivity of these facilities to migrating fish species. Several of the applied technologies (e.g. Raspberry Pi, Arduino) are cheap and easily accessible. They provide a multitude of opportunities to facilitate data collection and prototype development in the environmental sciences.

Environmental impact of Hurricane Katrina on Lake Pontchartrain: Chapter 7G in Science and the storms-the USGS response to the hurricanes of 2005

USGS Publications Warehouse

Heitmuller, Thomas; Perez, Brian C.

2007-01-01

Hurricane Katrina slammed the Louisiana-Mississippi Gulf Coast with 135-mi/hour (217-km/hour) winds and up to a 30-ft (9-m) storm surge. Lake Pontchartrain was further subjected to environmental threat by way of the millions of gallons of contaminated flood water that were pumped daily from the city of New Orleans into the lake.

A User Definable SLAM Airfield Model Designed for Experimentation and Analysis. Volume II

DTIC Science & Technology

1982-03-01

St), 2015 ATRIB(8)=TNOWU; 2016 ACT, ,USERF (37) .GE.ZvLZF4; 2#17 ACT, .0001,*L2SZ; 2018 2#19 LZF4 ASSIGNiI:ATRIB(46), 72 2521 ACTi.1991ttLZSZ; 2922...nature than thobe covered in the main text. So.ne were added because thcre were adlditional co1aLlenltS which needed to bL made to a jjo bible user

Air-Sea Battle through Joint Training: Power Projection Sustainability

DTIC Science & Technology

2014-05-15

9 generate our decisive advantage.” 39 An example of cross-domain operations employed by the USN and USAF was the release of an AGM-154C Joint...and Herzegovina. While employing a USAF GBU -15 “electro-optically guided” bomb within close range of a USN AGM-84 SLAM-ER, “electronic... 39 U.S. Office of the Chairman, Joint Chiefs of Staff. Capstone Concept for Joint Operations: Joint Force 2020

A General Purpose Feature Extractor for Light Detection and Ranging Data

DTIC Science & Technology

2010-11-17

datasets, and the 3D MIT DARPA Urban Challenge dataset. Keywords: SLAM ; LIDARs ; feature detection; uncertainty estimates; descriptors 1. Introduction The...November 2010 Abstract: Feature extraction is a central step of processing Light Detection and Ranging ( LIDAR ) data. Existing detectors tend to exploit...detector for both 2D and 3D LIDAR data that is applicable to virtually any environment. Our method adapts classic feature detection methods from the image

Ceramic Gas Turbine Engine Demonstration Program

DTIC Science & Technology

1982-05-01

of Radiographs 124 5.2.3 Ultrasonic NDE 127 5.2.4 Scanning Laser Acoustic Microscopy 132 5.2.5 Microwave NDE 134 5.2.6 Neutron Radiography 134 5.2.7...microwaves, and scanning loser acoustic microscopy (SLAM) were evaluated using the standards containing known defects. Component shape standards...mounted in a carousel and rotated in the high velocity combustor gases. The temperature is measured by an infrared pyrometer 95 TABLE 4-3. SUMMARY OF

Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus.

PubMed

Dutter, Brendan F; Mike, Laura A; Reid, Paul R; Chong, Katherine M; Ramos-Hunter, Susan J; Skaar, Eric P; Sulikowski, Gary A

2016-05-20

Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if these activities are linked and establish what features of the molecule are required for activity, we synthesized a library of analogs around the structure of 1 and screened them for activation of heme biosynthesis and anaerobic toxicity to investigate structure-activity relationships. The results of this analysis suggest that these activities are not linked. Furthermore, we have identified the structural features that promote each activity and have established two classes of molecules: activators of heme biosynthesis and inhibitors of anaerobic growth. These molecules will serve as useful probes for their respective activities without concern for the off target effects of the parent compound.

Mortality of people with chronic fatigue syndrome: a retrospective cohort study in England and Wales from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) Register.

PubMed

Roberts, Emmert; Wessely, Simon; Chalder, Trudie; Chang, Chin-Kuo; Hotopf, Matthew

2016-04-16

Mortality associated with chronic fatigue syndrome is uncertain. We investigated mortality in individuals diagnosed with chronic fatigue syndrome in secondary and tertiary care using data from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) register. We calculated standardised mortality ratios (SMRs) for all-cause, suicide-specific, and cancer-specific mortality for a 7-year observation period using the number of deaths observed in SLaM records compared with age-specific and sex-specific mortality statistics for England and Wales. Study participants were included if they had had contact with the chronic fatigue service (referral, discharge, or case note entry) and received a diagnosis of chronic fatigue syndrome. We identified 2147 cases of chronic fatigue syndrome from CRIS and 17 deaths from Jan 1, 2007, to Dec 31, 2013. 1533 patients were women of whom 11 died, and 614 were men of whom six died. There was no significant difference in age-standardised and sex-standardised mortality ratios (SMRs) for all-cause mortality (SMR 1·14, 95% CI 0·65-1·85; p=0·67) or cancer-specific mortality (1·39, 0·60-2·73; p=0·45) in patients with chronic fatigue syndrome when compared with the general population in England and Wales. This remained the case when deaths from suicide were removed from the analysis. There was a significant increase in suicide-specific mortality (SMR 6·85, 95% CI 2·22-15·98; p=0·002). We did not note increased all-cause mortality in people with chronic fatigue syndrome, but our findings show a substantial increase in mortality from suicide. This highlights the need for clinicians to be aware of the increased risk of completed suicide and to assess suicidality adequately in patients with chronic fatigue syndrome. National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London. Copyright © 2016 Roberts et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd.. All rights reserved.

Active colloidal molecules

NASA Astrophysics Data System (ADS)

Löwen, Hartmut

2018-03-01

Like ordinary molecules are composed of atoms, colloidal molecules consist of several species of colloidal particles tightly bound together. If one of these components is self-propelled or swimming, novel “active colloidal molecules” emerge. Active colloidal molecules exist on various levels such as “homonuclear”, “heteronuclear” and “polymeric” and possess a dynamical function moving as propellers, spinners or rotors. Self-assembly of such active complexes has been studied a lot recently and this perspective article summarizes recent progress and gives an outlook to future developments in the rapidly expanding field of active colloidal molecules.

Floating shock fitting via Lagrangian adaptive meshes

NASA Technical Reports Server (NTRS)

Vanrosendale, John

1995-01-01

In recent work we have formulated a new approach to compressible flow simulation, combining the advantages of shock-fitting and shock-capturing. Using a cell-centered on Roe scheme discretization on unstructured meshes, we warp the mesh while marching to steady state, so that mesh edges align with shocks and other discontinuities. This new algorithm, the Shock-fitting Lagrangian Adaptive Method (SLAM), is, in effect, a reliable shock-capturing algorithm which yields shock-fitted accuracy at convergence.

An Improved Maintenance Model for the Simulation of Strategic Airlift Capability.

DTIC Science & Technology

1982-03-01

developed using SLAM as the primary simulation language. Maintenance manning is modeled at the Air Force Specialty Code level, to allow the possibility of...Atlantic Treaty Organization (NATO) allies is one of our primary national objectives, but recent increases in Soviet ground and air forces (Ref 5:100) have...arrive from the United States. Consequently, the primary objective of the United States Air Force mobility program is to be able, by 1982, to double the

Profile of a Terrorist.

DTIC Science & Technology

1988-04-01

in their quarters by the Beirut International Airport. A Mercedes - Benz truck passed a Lebanese checkpoint and a Marine sentry guard before slamming...as "the use or threat of violence, a method of combat or strategy to achieve certain goals, that its aim is to induce a state of fear in the victim...that it is ruthless, and does not conform to humanitarian norms and that publicity is an essential factor in terrorist strategy ." (19:88) This is the

Micro Autonomous Systems and Technology: A Methodology for Quantitative Technology Assessment and Prototyping of Unmanned Vehicles

DTIC Science & Technology

2012-01-30

Sensors: LIDAR , Camera, SONAR) is qualitatively or quantitatively ranked against the other options in such categories as weight and power consumption...Mapping ( SLAM ) and A*. The second software change in progress is upgrading from Unreal 2004 to is a bridge between an external program that defines a...current simulation setup, a simulated quad-copter with an Inertial Navigation System (INS) and ranging LIDAR sensor spawns within an environment and

Earth Science

NASA Image and Video Library

2002-10-02

This photo of hurricane Lili, captured during the Expedition Five mission, shows the compact storm system and the structure of its estimated 15 nautical mile wide eye. After strengthening to a Category 4 storm (125 knots with the central pressure of 940 millibars), Lili weakened to a Category 2 before slamming into the central coast of Louisiana just south of Lafayette. This is one of many photos that stem form the Crew Observation (CEO) experiment that has been a part of every Space Station expedition.

The Use of EPI-Splines to Model Empirical Semivariograms for Optimal Spatial Estimation

DTIC Science & Technology

2016-09-01

proliferation of unmanned systems in military and civilian sectors has occurred at lightning speed. In the case of Autonomous Underwater Vehicles or...SLAM is a method of position estimation that relies on map data [3]. In this process, the creation of the map occurs as the vehicle is navigating the...that ensures minimal errors. This technique is accomplished in two steps. The first step is creation of the semivariogram. The semivariogram is a

Hurricane Lili

NASA Technical Reports Server (NTRS)

2002-01-01

This photo of hurricane Lili, captured during the Expedition Five mission, shows the compact storm system and the structure of its estimated 15 nautical mile wide eye. After strengthening to a Category 4 storm (125 knots with the central pressure of 940 millibars), Lili weakened to a Category 2 before slamming into the central coast of Louisiana just south of Lafayette. This is one of many photos that stem form the Crew Observation (CEO) experiment that has been a part of every Space Station expedition.

An Analysis of the Centaur Ground Processing System at the Kennedy Space Center/Cape Canaveral AFS.

DTIC Science & Technology

1985-12-01

SPONSORING 8tn OFF ICE SYMBOL 9 . PROCUREMENT INSTRUMENT IDENTIFiCATION NUMBER 0 RG4NICATICN II appsicable, * cADDRESS C-;t,. S:sI. and~ /11’ L,a,, .0...The PERT Network................8 2. The SLAM Model................. 9 F. Outline of the Paper................13 Ii. The Shuttle/Centaur G System...104 9 . AWAIT NODE..................104 10. FREE NODE...................105 11. ASSIGN NODE..................105 w 12. COLCT NODE

Slamming pressures on the bottom of a free-falling vertical wedge

NASA Astrophysics Data System (ADS)

Ikeda, C. M.; Judge, C. Q.

2013-11-01

High-speed planing boats are subjected to repeat impacts due to slamming, which can cause structural damage and injury to passengers. A first step in understanding and predicting the physics of a craft re-entering the water after becoming partially airborne is an experimental vertical drop test of a prismastic wedge (deadrise angle, β =20° beam, B = 300 mm; and length, L = 600 mm). The acrylic wedge was mounted to a rig allowing it to free-fall into a deep-water tank (5.2m × 5.2m × 4.2m deep) from heights 0 <= H <= 635 mm, measured from the keel to the free surface. The wedge was instrumented to record vertical position, acceleration, and pressure on the bottom surface. A pressure mapping system, capable of measuring several points over the area of the thin (0.1 mm) film sensor at sampling rates up to 20 kHz, is used and compared to surface-mounted pressure transducers (sampled at 10 kHz). A high speed camera (1000 fps, resolution of 1920 × 1200 pixels) is mounted above the wedge model to record the wetted surface as the wedge descended below the free surface. The pressure measurements taken with both conventional surface pressure transducers and the pressure mapping system agree within 10% of the peak pressure values (0.7 bar, typical). Supported by the Office of Naval Research.

Three-dimensional water impact at normal incidence to a blunt structure

PubMed Central

Cooker, M. J.; Korobkin, A. A.

2016-01-01

The three-dimensional water impact onto a blunt structure with a spreading rectangular contact region is studied. The structure is mounted on a flat rigid plane with the impermeable curved surface of the structure perpendicular to the plane. Before impact, the water region is a rectangular domain of finite thickness bounded from below by the rigid plane and above by the flat free surface. The front free surface of the water region is vertical, representing the front of an advancing steep wave. The water region is initially advancing towards the structure at a constant uniform speed. We are concerned with the slamming loads acting on the surface of the structure during the initial stage of water impact. Air, gravity and surface tension are neglected. The problem is analysed by using some ideas of pressure-impulse theory, but including the time-dependence of the wetted area of the structure. The flow caused by the impact is three-dimensional and incompressible. The distribution of the pressure-impulse (the time-integral of pressure) over the surface of the structure is analysed and compared with the distributions provided by strip theories. The total impulse exerted on the structure during the impact stage is evaluated and compared with numerical and experimental predictions. An example calculation is presented of water impact onto a vertical rigid cylinder. Three-dimensional effects on the slamming loads are the main concern in this study. PMID:27616912

Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

PubMed Central

Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

2015-01-01

Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach. PMID:26151203

Attachment of second harmonic-active moiety to molecules for detection of molecules at interfaces

DOEpatents

Salafsky, Joshua S.; Eisenthal, Kenneth B.

2005-10-11

This invention provides methods of detecting molecules at an interface, which comprise labeling the molecules with a second harmonic-active moiety and detecting the labeled molecules at the interface using a surface selective technique. The invention also provides methods for detecting a molecule in a medium and for determining the orientation of a molecular species within a planar surface using a second harmonic-active moiety and a surface selective technique.

A single molecule perspective on the functional diversity of in vitro evolved β-glucuronidase.

PubMed

Liebherr, Raphaela B; Renner, Max; Gorris, Hans H

2014-04-23

The mechanisms that drive the evolution of new enzyme activity have been investigated by comparing the kinetics of wild-type and in vitro evolved β-glucuronidase (GUS) at the single molecule level. Several hundred single GUS molecules were separated in large arrays of 62,500 ultrasmall reaction chambers etched into the surface of a fused silica slide to observe their individual substrate turnover rates in parallel by fluorescence microscopy. Individual GUS molecules feature long-lived but divergent activity states, and their mean activity is consistent with classic Michaelis-Menten kinetics. The large number of single molecule substrate turnover rates is representative of the activity distribution within an entire enzyme population. Partially evolved GUS displays a much broader activity distribution among individual enzyme molecules than wild-type GUS. The broader activity distribution indicates a functional division of work between individual molecules in a population of partially evolved enzymes that-as so-called generalists-are characterized by their promiscuous activity with many different substrates.

Responses to Microbial Challenges by SLAMF Receptors

PubMed Central

van Driel, Boaz Job; Liao, Gongxian; Engel, Pablo; Terhorst, Cox

2016-01-01

The SLAMF family (SLAMF) of cell surface glycoproteins is comprised of nine glycoproteins and while SLAMF1, 3, 5, 6, 7, 8, and 9 are self-ligand receptors, SLAMF2 and SLAMF4 interact with each other. Their interactions induce signal transduction networks in trans, thereby shaping immune cell–cell communications. Collectively, these receptors modulate a wide range of functions, such as myeloid cell and lymphocyte development, and T and B cell responses to microbes and parasites. In addition, several SLAMF receptors serve as microbial sensors, which either positively or negatively modulate the function of macrophages, dendritic cells, neutrophils, and NK cells in response to microbial challenges. The SLAMF receptor–microbe interactions contribute both to intracellular microbicidal activity as well as to migration of phagocytes to the site of inflammation. In this review, we describe the current knowledge on how the SLAMF receptors and their specific adapters SLAM-associated protein and EAT-2 regulate innate and adaptive immune responses to microbes. PMID:26834746

Robot soccer anywhere: achieving persistent autonomous navigation, mapping, and object vision tracking in dynamic environments

NASA Astrophysics Data System (ADS)

Dragone, Mauro; O'Donoghue, Ruadhan; Leonard, John J.; O'Hare, Gregory; Duffy, Brian; Patrikalakis, Andrew; Leederkerken, Jacques

2005-06-01

The paper describes an ongoing effort to enable autonomous mobile robots to play soccer in unstructured, everyday environments. Unlike conventional robot soccer competitions that are usually held on purpose-built robot soccer "fields", in our work we seek to develop the capability for robots to demonstrate aspects of soccer-playing in more diverse environments, such as schools, hospitals, or shopping malls, with static obstacles (furniture) and dynamic natural obstacles (people). This problem of "Soccer Anywhere" presents numerous research challenges including: (1) Simultaneous Localization and Mapping (SLAM) in dynamic, unstructured environments, (2) software control architectures for decentralized, distributed control of mobile agents, (3) integration of vision-based object tracking with dynamic control, and (4) social interaction with human participants. In addition to the intrinsic research merit of these topics, we believe that this capability would prove useful for outreach activities, in demonstrating robotics technology to primary and secondary school students, to motivate them to pursue careers in science and engineering.

Human Diversity in a Cell Surface Receptor that Inhibits Autophagy.

PubMed

Chaudhary, Anu; Leite, Mara; Kulasekara, Bridget R; Altura, Melissa A; Ogahara, Cassandra; Weiss, Eli; Fu, Wenqing; Blanc, Marie-Pierre; O'Keeffe, Michael; Terhorst, Cox; Akey, Joshua M; Miller, Samuel I

2016-07-25

Mutations in genes encoding autophagy proteins have been associated with human autoimmune diseases, suggesting that diversity in autophagy responses could be associated with disease susceptibility or severity. A cellular genome-wide association study (GWAS) screen was performed to explore normal human diversity in responses to rapamycin, a microbial product that induces autophagy. Cells from several human populations demonstrated variability in expression of a cell surface receptor, CD244 (SlamF4, 2B4), that correlated with changes in rapamycin-induced autophagy. High expression of CD244 and receptor activation with its endogenous ligand CD48 inhibited starvation- and rapamycin-induced autophagy by promoting association of CD244 with the autophagy complex proteins Vps34 and Beclin-1. The association of CD244 with this complex reduced Vps34 lipid kinase activity. Lack of CD244 is associated with auto-antibody production in mice, and lower expression of human CD244 has previously been implicated in severity of human rheumatoid arthritis and systemic lupus erythematosus, indicating that increased autophagy as a result of low levels of CD244 may alter disease outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Innovating science communication: the structure supporting ATLAS Education & Outreach

NASA Astrophysics Data System (ADS)

Goldfarb, Steven; Marcelloni, Claudia; Shaw, Kate; ATLAS Experiment

2016-04-01

The ATLAS Education & Outreach project has, over the years, developed a strong reputation for supporting innovation. Animated event displays, musical CDs, 3d movies, 3-storey murals, photo books, data sonifications, multi-media art installations, pub slams, masterclasses, documentaries, pop-up books, LEGO® models, and virtual visits are among the many diverse methods being exploited to communicate to the world the goals and accomplishments of the ATLAS Experiment at CERN. This variety of creativity and innovation does not pop out of a vacuum. It requires underlying motivation by the collaboration to communicate with the public; freedom and encouragement to do so in a creative manner; and a support structure for developing, implementing and promoting these activities. The ATLAS Outreach project has built this support structure on a well-defined communication plan, high-quality content, and effective delivery platforms. Most importantly, implementation of the program has been based on the effective engagement of the participating institutes and other key partners, not only to leverage modest human resources and funding, but also to take advantage of the rich imagination and inspiration of a diverse, global human collaboration. We present our current plan, on-going activities, and a few more fun innovations for the future.

Alternative activation modifies macrophage resistance to Mycobacterium bovis.

PubMed

Castillo-Velázquez, Uziel; Aranday-Cortés, Elihú; Gutiérrez-Pabello, José A

2011-07-05

The aim of this study was to evaluate the influence of macrophage alternative activation in the intracellular pathogen natural disease resistance phenotype of the host. Macrophage monolayers from resistant (R) (3) or susceptible (S) (3) cattle donors were treated with 10 ng/ml of bovine recombinant IL-4 (rbIL-4), and infected with virulent and avirulent Mycobacterium bovis (MOI 10:1). Bactericidal assays were performed to assess the bacterial phagocytic index and intracellular survival. Total RNA was reverse transcribed and used to analyze the relative changes in gene expression of IL-10, IL-12, IL-18 IL-1β, TNF-α, MCP-1, MCP-2, IL-6, MIP-1, MIP-3, iNOS, ARGII and SLAM by real time PCR. Cell supernatants were collected and nitric oxide and arginase production was assessed. Apoptosis induction was measured by TUNEL. IL-4 treatment increased the phagocytic index in both R and S macrophages; however intracellular survival was augmented mainly in S macrophages. Alternative activation decreased gene expression of pro-inflammatory cytokines, nitric oxide production and DNA fragmentation mainly in R macrophages. On the other hand, arginase production was not different between R and S macrophages. Alternative activation modifies the macrophage response against M. bovis. IL-4 treatment minimized the functional differences that exist between R and S macrophages. Copyright © 2011. Published by Elsevier B.V.

Quantifying Mitigation Characteristics of Shock Isolation Seats in a Wave Impact Environment

DTIC Science & Technology

2015-01-01

thank Dr. Jack L. Price , Director of Research, Naval Surface Warfare Center, Carderock Division for overall management of wave slam phenomenology...of the Z and X acceleration vectors is used as an indicator of the change in impact angle for different types of wave impacts (i.e., skimming on a...acceleration vector is on the order of 87.7 degrees from the deck surface (or 2.3 degrees from normal to the deck, as in skimming a wave crest or

America First Isolationism in U.S. Foreign Policy from the 19th to the 21st Century

DTIC Science & Technology

2017-06-01

internationalist policy pursued since the Second World War. I assume the answer is “No,” but an ex - post analysis will show the impact of his new mercantilist...his opponent Hillary Clinton to describe him as a “dangerous isolationist,” according to Washington Post correspondent Anne Gearan.3 But, is...Speech,” Washington Post , August 31, 2016, https://www.washingtonpost.com/news/ post - politics/wp/2016/08/31/clinton-plans-to-slam-trump-as-a-dangerous

Real-Time NDE Using Multi-Function Robotic Sonoscope (MSRF)

DTIC Science & Technology

1991-12-31

constants of graphite fibers using SLAM, operating in a interferogram mode. Also measuring the stress in a Nicalon (SiC) fiber reinforced LAS ...demonstrated. Several Nicolan fibers reinforced LAS composites were used in the studies. A four-point bending fixture applying a known strain to the...was caused by a 0.16 Xc impacto - a"L a s?eed of 6-7 m/s. The field of view is 45 ran x 2 6 mm Mass 0.16 Kg Velocity = 6.70 m

Evaluation of Hardware and Software for a Small Autonomous Underwater Vehicle Navigation System (SANS)

DTIC Science & Technology

1994-09-01

Hyslop , G.L., Schieber, G.E., Schwartz, M.K., "Automated Mission Planning for the Standoff Land Attack Missile (SLAM)", Proceedings of the...1993, pp. 277-290. [PARK80] Parkinson, B.W., "Overview", Global Positioning System, Vol. 1, The Institute of Navigation, Washington, D.C., 1980 , pp...Navigation Message", Global Positioning System, Vol. 1, The Institute of Navigation, Washington, D.C., 1980 , pp. 55-73. 139 [WOOD851 Wooden, W. H

Integrated High-Fidelity CFD/FE FSI Code Development and Benchmark Full-Scale Validation EFD for Slamming Analysis

DTIC Science & Technology

2016-06-30

measurements as well as of the stiffness of the hull can be obtained by using measurements (accelerometer and gyro data) from one location of the boat to...assuming a rigid hull ) to bulkhead #5. The two estimates match exceptionally well. The data shown are fairly typical from operating the Nurnerette in...indicated in dE~ figure. The hull was designed to 2: G so it should be no surprise that the structure under ..vent permanent deformation during this

Active-Site Hydration and Water Diffusion in Cytochrome P450cam: A Highly Dynamic Process

PubMed Central

Miao, Yinglong; Baudry, Jerome

2011-01-01

Long-timescale molecular dynamics simulations (300 ns) are performed on both the apo- (i.e., camphor-free) and camphor-bound cytochrome P450cam (CYP101). Water diffusion into and out of the protein active site is observed without biased sampling methods. During the course of the molecular dynamics simulation, an average of 6.4 water molecules is observed in the camphor-binding site of the apo form, compared to zero water molecules in the binding site of the substrate-bound form, in agreement with the number of water molecules observed in crystal structures of the same species. However, as many as 12 water molecules can be present at a given time in the camphor-binding region of the active site in the case of apo-P450cam, revealing a highly dynamic process for hydration of the protein active site, with water molecules exchanging rapidly with the bulk solvent. Water molecules are also found to exchange locations frequently inside the active site, preferentially clustering in regions surrounding the water molecules observed in the crystal structure. Potential-of-mean-force calculations identify thermodynamically favored trans-protein pathways for the diffusion of water molecules between the protein active site and the bulk solvent. Binding of camphor in the active site modifies the free-energy landscape of P450cam channels toward favoring the diffusion of water molecules out of the protein active site. PMID:21943431

Fully Self-Contained Vision-Aided Navigation and Landing of a Micro Air Vehicle Independent from External Sensor Inputs

NASA Technical Reports Server (NTRS)

Brockers, Roland; Susca, Sara; Zhu, David; Matthies, Larry

2012-01-01

Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets.

Can risk assessment predict suicide in secondary mental healthcare? Findings from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Case Register.

PubMed

Lopez-Morinigo, Javier-David; Fernandes, Andrea C; Shetty, Hitesh; Ayesa-Arriola, Rosa; Bari, Ashraful; Stewart, Robert; Dutta, Rina

2018-06-02

The predictive value of suicide risk assessment in secondary mental healthcare remains unclear. This study aimed to investigate the extent to which clinical risk assessment ratings can predict suicide among people receiving secondary mental healthcare. Retrospective inception cohort study (n = 13,758) from the South London and Maudsley NHS Foundation Trust (SLaM) (London, UK) linked with national mortality data (n = 81 suicides). Cox regression models assessed survival from the last suicide risk assessment and ROC curves evaluated the performance of risk assessment total scores. Hopelessness (RR = 2.24, 95% CI 1.05-4.80, p = 0.037) and having a significant loss (RR = 1.91, 95% CI 1.03-3.55, p = 0.041) were significantly associated with suicide in the multivariable Cox regression models. However, screening statistics for the best cut-off point (4-5) of the risk assessment total score were: sensitivity 0.65 (95% CI 0.54-0.76), specificity 0.62 (95% CI 0.62-0.63), positive predictive value 0.01 (95% CI 0.01-0.01) and negative predictive value 0.99 (95% CI 0.99-1.00). Although suicide was linked with hopelessness and having a significant loss, risk assessment performed poorly to predict such an uncommon outcome in a large case register of patients receiving secondary mental healthcare.

Overexpression of adhesion molecules and barrier molecules is associated with differential infiltration of immune cells in non-small cell lung cancer.

PubMed

Chae, Young Kwang; Choi, Wooyoung M; Bae, William H; Anker, Jonathan; Davis, Andrew A; Agte, Sarita; Iams, Wade T; Cruz, Marcelo; Matsangou, Maria; Giles, Francis J

2018-01-18

Immunotherapy is emerging as a promising option for lung cancer treatment. Various endothelial adhesion molecules, such as integrin and selectin, as well as various cellular barrier molecules such as desmosome and tight junctions, regulate T-cell infiltration in the tumor microenvironment. However, little is known regarding how these molecules affect immune cells in patients with lung cancer. We demonstrated for the first time that overexpression of endothelial adhesion molecules and cellular barrier molecule genes was linked to differential infiltration of particular immune cells in non-small cell lung cancer. Overexpression of endothelial adhesion molecule genes is associated with significantly lower infiltration of activated CD4 and CD8 T-cells, but higher infiltration of activated B-cells and regulatory T-cells. In contrast, overexpression of desmosome genes was correlated with significantly higher infiltration of activated CD4 and CD8 T-cells, but lower infiltration of activated B-cells and regulatory T-cells in lung adenocarcinoma. This inverse relation of immune cells aligns with previous studies of tumor-infiltrating B-cells inhibiting T-cell activation. Although overexpression of endothelial adhesion molecule or cellular barrier molecule genes alone was not predictive of overall survival in our sample, these genetic signatures may serve as biomarkers of immune exclusion, or resistance to T-cell mediated immunotherapy.

Formation, structure, and evolution of boiling nucleus and interfacial tension between bulk liquid phase and nucleus

NASA Astrophysics Data System (ADS)

Wang, Xiao-Dong; Peng, Xiao-Feng; Tian, Yong; Wang, Bu-Xuan

2005-05-01

In this paper, the concept of the molecular free path is introduced to derive a criterion distinguishing active molecules from inactive molecules in liquid phase. A concept of the critical aggregation concentration (CAC) of active molecules is proposed to describe the physical configuration before the formation of a nucleus during vapor-liquid phase transition. All active molecules exist as monomers when the concentration of active molecules is lower than CAC, while the active molecules will generate aggregation once the concentration of the active molecules reaches CAC. However, these aggregates with aggregation number, N, smaller than five can steadily exist in bulk phase. The other excess active molecules can only produce infinite aggregation and form a critical nucleus of vapor-liquid phase transition. Without any outer perturbation the state point of CAC corresponds to the critical superheated or supercooled state. Meanwhile, a model of two-region structure of a nucleus is proposed to describe nucleus evolution. The interfacial tension between bulk liquid phase and nucleus is dependent of the density gradient in the transition region and varies with the structure change of the transition region. With the interfacial tension calculated using this model, the predicted nucleation rate is very close to the experimental measurement. Furthermore, this model and associated analysis provides solid theoretical evidences to clarify the definition of nucleation rate and understand nucleation phenomenon with the insight into the physical nature.

Asymmetric bagging and feature selection for activities prediction of drug molecules.

PubMed

Li, Guo-Zheng; Meng, Hao-Hua; Lu, Wen-Cong; Yang, Jack Y; Yang, Mary Qu

2008-05-28

Activities of drug molecules can be predicted by QSAR (quantitative structure activity relationship) models, which overcomes the disadvantages of high cost and long cycle by employing the traditional experimental method. With the fact that the number of drug molecules with positive activity is rather fewer than that of negatives, it is important to predict molecular activities considering such an unbalanced situation. Here, asymmetric bagging and feature selection are introduced into the problem and asymmetric bagging of support vector machines (asBagging) is proposed on predicting drug activities to treat the unbalanced problem. At the same time, the features extracted from the structures of drug molecules affect prediction accuracy of QSAR models. Therefore, a novel algorithm named PRIFEAB is proposed, which applies an embedded feature selection method to remove redundant and irrelevant features for asBagging. Numerical experimental results on a data set of molecular activities show that asBagging improve the AUC and sensitivity values of molecular activities and PRIFEAB with feature selection further helps to improve the prediction ability. Asymmetric bagging can help to improve prediction accuracy of activities of drug molecules, which can be furthermore improved by performing feature selection to select relevant features from the drug molecules data sets.

Delocalization of frontier orbitals induced red emission for heptazine based thermally activated delayed fluorescence molecule: First-principles study

NASA Astrophysics Data System (ADS)

Kang, Yongxiang; Zhao, Liyun; Leng, Jiancai

2018-04-01

Design of red organic emitting molecules with characteristic of thermally activated delayed fluorescence (TADF) remains a great challenge. Here, electronic and optical properties of a series of multi-branched TADF molecules have been investigated based on the newly-proposed optimal Hartree-Fock percentage method. Results show that, though enlarging the delocalization of HOMO and LUMO, the emission wavelength is redshift. The designed red TADF molecule possesses smaller reorganization energy than these for reported molecules. This indicates the non-radiative energy consumption of excited state is small and effective luminescence can be expected. Thus, a promising red thermally activated delayed fluorescence molecule is proposed.

Dual signaling by innate and adaptive immune receptors is required for TLR7-induced B-cell-mediated autoimmunity.

PubMed

Walsh, Elizabeth R; Pisitkun, Prapaporn; Voynova, Elisaveta; Deane, Jonathan A; Scott, Bethany L; Caspi, Rachel R; Bolland, Silvia

2012-10-02

Toll-like receptor 7 (Tlr7) has been linked to systemic lupus disease incidence in humans and mice, but how TLR7 potentiates autoimmunity is unclear. We used a Tlr7 transgenic (tg) mouse model to investigate the cellular and molecular events required to induce spontaneous autoimmunity through increased TLR7 activity. We determined that Tlr7 exerts B-cell-intrinsic effects in promoting spontaneous germinal center (GC) and plasmablast B-cell development, and that these B-cell subsets are dependent on T-cell-derived signals through CD40L and SLAM-associated protein (SAP), but not IL-17. Antigen specificity also factored into TLR7-induced disease, as both a restricted T cell receptor (TCR) specificity and MHC haplotype H2(k/k) protected Tlr7tg mice from spontaneous lymphocyte activation and autoantibody production. Inflammatory myeloid cell expansion and autoimmunity did not develop in Tlr7tgIgH(-/-) mice, suggesting either that spontaneous TLR7 activation does not occur in dendritic cells, or, if it does occur, cannot drive these events in the absence of B-cell aid. These data indicate that autoimmune disease in Tlr7tg mice is contingent upon B cells receiving stimulation both through innate pathways and T-cell-derived signals and suggest a codependent relationship between B cells and T cells in the development of autoimmunity.

Software Models Impact Stresses

NASA Technical Reports Server (NTRS)

Hanshaw, Timothy C.; Roy, Dipankar; Toyooka, Mark

1991-01-01

Generalized Impact Stress Software designed to assist engineers in predicting stresses caused by variety of impacts. Program straightforward, simple to implement on personal computers, "user friendly", and handles variety of boundary conditions applied to struck body being analyzed. Applications include mathematical modeling of motions and transient stresses of spacecraft, analysis of slamming of piston, of fast valve shutoffs, and play of rotating bearing assembly. Provides fast and inexpensive analytical tool for analysis of stresses and reduces dependency on expensive impact tests. Written in FORTRAN 77. Requires use of commercial software package PLOT88.

Examination of silicon solar cells by means of the Scanning Laser Acoustic Microscope (SLAM)

NASA Technical Reports Server (NTRS)

Vorres, C.; Yuhas, D. E.

1981-01-01

The Scanning Laser Acoustic Microscope produces images of internal structure in materials. The acoustic microscope is an imaging system based upon acoustic rather than electromagnetic waves. Variations in the elastic propertis are primarily responsible for structure visualized in acoustic micrographs. The instrument used in these investigations is the SONOMICROSCOPE 100 which can be operated at ultrasonic frequencies of from 30 MHz to 500 MHz. The examination of the silicon solar cells was made at 100 MHz. Data are presented in the form of photomicrographs.

3D modeling of underground objects with the use of SLAM technology on the example of historical mine in Ciechanowice (Ołowiane Range, The Sudetes)

NASA Astrophysics Data System (ADS)

Wajs, Jaroslaw; Kasza, Damian; Zagożdżon, Paweł P.; Zagożdżon, Katarzyna D.

2018-01-01

Terrestrial Laser Scanning is a currently one of the most popular methods for producing representations of 3D objects. This paper presents the potential of applying the mobile laser scanning method to inventory underground objects. The examined location was a historic crystalline limestone mine situated in the vicinity of Ciechanowice village (Kaczawa Mts., SW Poland). The authors present a methodology for performing measurements and for processing the obtained results, whose accuracy is additionally verified.

Application of scanning acoustic microscopy to advanced structural ceramics

NASA Technical Reports Server (NTRS)

Vary, Alex; Klima, Stanley J.

1987-01-01

A review is presentod of research investigations of several acoustic microscopy techniques for application to structural ceramics for advanced heat engines. Results obtained with scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), scanning electron acoustic microscopy (SEAM), and photoacoustic microscopy (PAM) are compared. The techniques were evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described with emphasis on statistics of detectability of flaws that constitute potential fracture origins.

A Slam Model of the Armed Forces Courier Service CONUS Stations: A Strategic Planning Tool.

DTIC Science & Technology

1985-09-01

ii .-- - ". . ’. . i i . - , i i . "-. - -’’" . .’’ ’- -. . . . . ... .’ 12? .2.2i?.i..- .’- .- j ’. .. . . . ... i ’< - ," ’i.-l -.- ’. ,. .l...of a simulation model that provides the ARFCOS top managers with a strategic planning tool for determining ,< .- .. -F -- ....F .,I . .. , j -.... io...i ,. i .< - j ’ ’. -.- ’i’iii ,. . - - . -.- ’ < . ,] . . F . ’I 1 " vehicle weight carrying requirements, and manpower needs for their different

Validation of Numerical Predictions of the Impact Forces and Hydrodynamics of a Deep-V Planing Hull

DTIC Science & Technology

2012-12-01

technique. NFA uses an implicit subgrid- scale model that is built into the treatment of the convective terms in the momentum equations [14]. A...delivered to SAIC under the Navy DASS (Dynamic Assessment of Surface Ship) 8 NSWCCD-50-TR-2012/040 project in 1998. SLAM2D has two solution methods: (1...is in knots-ft-1/2]. Model Scale Pressure [psi] -0.04 0.0 004 0.08 0.12 0.16 Figure 25. Pressures on hull for CA=0.608, L/b=4 and

Frequency dependence of tissue attenuation measured by acoustic microscopy.

PubMed

Daft, C M; Briggs, G A; O'Brien, W D

1989-05-01

Broadband scanning acoustic microscopy (SAM) has been used to investigate the mechanical properties of sections of tissue with a resolution of around 8 microns. The work reported here extends these results by reporting the frequency dependence of the attenuation coefficient from 100-500 MHz. A discussion of the theory of the measurements is presented. The scanning laser acoustic microscope (SLAM) is used to characterize similar tissue sections at 100 MHz. The data obtained with the two forms of acoustic microscopy are compared with results from the literature.

A Consistent Wave Impact Load Model for Studying Structure, Equipment Ruggedness, Shock Isolation Seats, and Human Comfort in Small High Speed Craft

DTIC Science & Technology

2016-11-01

acceleration at a cross-section was used as a measure of the wave impact load in units of g. Later developments included publication of the envelope...Republic, 4 – 7 October 2004. PICKFORD, E.V., MAHONE, R.R., WOLK, H.L. (1975). Slam/Shock Isolation Pedestal, United States Patent Number, 3,912,248, 14...accelerations. The rigid body peak acceleration is a measure of the impact load in units of g. In the following plots the data corresponds to head-sea

New Small Molecule Agonists to the Thyrotropin Receptor

PubMed Central

Ali, M. Rejwan; Ma, Risheng; David, Martine; Morshed, Syed A.; Ohlmeyer, Michael; Felsenfeld, Dan P.; Lau, Zerlina; Mezei, Mihaly; Davies, Terry F.

2015-01-01

Background Novel small molecular ligands (SMLs) to the thyrotropin receptor (TSHR) have potential as improved molecular probes and as therapeutic agents for the treatment of thyroid dysfunction and thyroid cancer. Methods To identify novel SMLs to the TSHR, we developed a transcription-based luciferase-cAMP high-throughput screening system and we screened 48,224 compounds from a 100K library in duplicate. Results We obtained 62 hits using the cut-off criteria of the mean±three standard deviations above the baseline. Twenty molecules with the greatest activity were rescreened against the parent CHO-luciferase cell for nonspecific activation, and we selected two molecules (MS437 and MS438) with the highest potency for further study. These lead molecules demonstrated no detectible cross-reactivity with homologous receptors when tested against luteinizing hormone (LH)/human chorionic gonadotropin receptor and follicle stimulating hormone receptor–expressing cells. Molecule MS437 had a TSHR-stimulating potency with an EC50 of 13×10−8 M, and molecule MS438 had an EC50 of 5.3×10−8 M. The ability of these small molecule agonists to bind to the transmembrane domain of the receptor and initiate signal transduction was suggested by their activation of a chimeric receptor consisting of an LHR ectodomain and a TSHR transmembrane. Molecular modeling demonstrated that these molecules bound to residues S505 and E506 for MS438 and T501 for MS437 in the intrahelical region of transmembrane helix 3. We also examined the G protein activating ability of these molecules using CHO cells co-expressing TSHRs transfected with luciferase reporter vectors in order to measure Gsα, Gβγ, Gαq, and Gα12 activation quantitatively. The MS437 and MS438 molecules showed potent activation of Gsα, Gαq, and Gα12 similar to TSH, but neither the small molecule agonists nor TSH showed activation of the Gβγ pathway. The small molecules MS437 and MS438 also showed upregulation of thyroglobulin (Tg), sodium iodine symporter (NIS), and TSHR gene expression. Conclusions Pharmacokinetic analysis of MS437 and MS438 indicated their pharmacotherapeutic potential, and their intraperitoneal administration to normal female mice resulted in significantly increased serum thyroxine levels, which could be maintained by repeated treatments. These molecules can therefore serve as lead molecules for further development of powerful TSH agonists. PMID:25333622

Isolation of rotational isomers and developments derived therefrom

PubMed Central

ŌKI, Michinori

2010-01-01

Isolation of rotational isomer models of ethane-type molecules is described. We could experimentally prove that, if rotational isomers whose molecular shape was chiral, the molecule could be optically active, even though it did not carry an asymmetric carbon atom. As an extension, other types of stereochemically fundamental and optically active molecules were isolated and their absolute stereochemistry was determined. One example is the model of meso-tartaric acid, for which optical inactivity had been attributed to internal compensation but is now explained as follows. On dissolution of meso-tartaric acid in a solvent, the molecule gives two kinds of conformers, one of which is a Ci molecule and the other is a C1 molecule. Although the latter is intrinsically optically active, the optical activity is cancelled by its enantiomer. The theory of internal compensation is recommended to be abandoned. As an extension to another area, some reactions of conformers are also discussed. PMID:21084771

Identification of PPARgamma Partial Agonists of Natural Origin (II): In Silico Prediction in Natural Extracts with Known Antidiabetic Activity

PubMed Central

Guasch, Laura; Sala, Esther; Mulero, Miquel; Valls, Cristina; Salvadó, Maria Josepa; Pujadas, Gerard; Garcia-Vallvé, Santiago

2013-01-01

Background Natural extracts have played an important role in the prevention and treatment of diseases and are important sources for drug discovery. However, to be effectively used in these processes, natural extracts must be characterized through the identification of their active compounds and their modes of action. Methodology/Principal Findings From an initial set of 29,779 natural products that are annotated with their natural source and using a previously developed virtual screening procedure (carefully validated experimentally), we have predicted as potential peroxisome proliferators-activated receptor gamma (PPARγ) partial agonists 12 molecules from 11 extracts known to have antidiabetic activity. Six of these molecules are similar to molecules with described antidiabetic activity but whose mechanism of action is unknown. Therefore, it is plausible that these 12 molecules could be the bioactive molecules responsible, at least in part, for the antidiabetic activity of the extracts containing them. In addition, we have also identified as potential PPARγ partial agonists 10 molecules from 16 plants with undescribed antidiabetic activity but that are related (i.e., they are from the same genus) to plants with known antidiabetic properties. None of the 22 molecules that we predict as PPARγ partial agonists show chemical similarity with a group of 211 known PPARγ partial agonists obtained from the literature. Conclusions/Significance Our results provide a new hypothesis about the active molecules of natural extracts with antidiabetic properties and their mode of action. We also suggest plants with undescribed antidiabetic activity that may contain PPARγ partial agonists. These plants represent a new source of potential antidiabetic extracts. Consequently, our work opens the door to the discovery of new antidiabetic extracts and molecules that can be of use, for instance, in the design of new antidiabetic drugs or functional foods focused towards the prevention/treatment of type 2 Diabetes Mellitus. PMID:23405231

Single-molecule conductance studies of photo-active and photochromic molecules

NASA Astrophysics Data System (ADS)

Tam, E. S.; Parks, J. J.; Santiago-Berrios, M. B.; Zhong, Y.-W.; Abruna, H. D.; Ralph, D. C.

2010-03-01

We perform statistical measurements of single molecule conductance in repeatedly-formed metal-molecule-metal junctions at room temperature. Our results on diaminoalkanes are consistent with those reported by the Venkataraman group. We focus on photo-active and photochromic molecules, including a series of transition-metal complexes with different metal centers and endgroups. We compare the trend in conductance across the family of complexes with that expected from electrochemical measurements. We will also report initial results on the voltage dependence of single-molecule conductances and the effects of optical excitations.

Misfolding of major histocompatibility complex class I molecules in activated T cells allows cis-interactions with receptors and signaling molecules and is associated with tyrosine phosphorylation.

PubMed

Santos, Susana G; Powis, Simon J; Arosa, Fernando A

2004-12-17

Knowledge of the origin and biochemical status of beta(2)-microglobulin-free or misfolded major histocompatibility complex (MHC)-I molecules is essential for understanding their pleiotropic properties. Here we show that in normal human T cells, misfolding of MHC-I molecules is turned on upon activation and cell division and is proportional to the level of proliferation. Immunoprecipitation showed that a number of proteins are associated with MHC-I heavy chains at the surface of activated T cells, including the CD8alphabeta receptor and the chaperone tandem calreticulin/ERp57, associations that rely upon the existence of a pool of HC-10-reactive molecules. Biochemical analysis showed that misfolded MHC-I molecules present at the cell surface are fully glycosylated mature molecules. Importantly, misfolded MHC-I molecules are tyrosine phosphorylated and are associated with kinase activity. In vitro kinase assays followed by reprecipitation indicated that tyrosine phosphorylation of the class I heavy chain is probably mediated by a Src tyrosine kinase because Lck was found associated with HC-10 immunocomplexes. Finally, we show that inhibition of tyrosine phosphorylation by using the Src-family tyrosine kinase inhibitor PP2 resulted in enhanced release of MHC-I heavy chains from the cell surface of activated T cells and a slight down-regulation of cell surface W6/32-reactive molecules. This study provides new insights into the biology of MHC-I molecules and suggests that tyrosine phosphorylation may be involved in the regulation of MHC-I misfolding and expression.

Indoor Modelling from Slam-Based Laser Scanner: Door Detection to Envelope Reconstruction

NASA Astrophysics Data System (ADS)

Díaz-Vilariño, L.; Verbree, E.; Zlatanova, S.; Diakité, A.

2017-09-01

Updated and detailed indoor models are being increasingly demanded for various applications such as emergency management or navigational assistance. The consolidation of new portable and mobile acquisition systems has led to a higher availability of 3D point cloud data from indoors. In this work, we explore the combined use of point clouds and trajectories from SLAM-based laser scanner to automate the reconstruction of building indoors. The methodology starts by door detection, since doors represent transitions from one indoor space to other, which constitutes an initial approach about the global configuration of the point cloud into building rooms. For this purpose, the trajectory is used to create a vertical point cloud profile in which doors are detected as local minimum of vertical distances. As point cloud and trajectory are related by time stamp, this feature is used to subdivide the point cloud into subspaces according to the location of the doors. The correspondence between subspaces and building rooms is not unambiguous. One subspace always corresponds to one room, but one room is not necessarily depicted by just one subspace, for example, in case of a room containing several doors and in which the acquisition is performed in a discontinue way. The labelling problem is formulated as combinatorial approach solved as a minimum energy optimization. Once the point cloud is subdivided into building rooms, envelop (conformed by walls, ceilings and floors) is reconstructed for each space. The connectivity between spaces is included by adding the previously detected doors to the reconstructed model. The methodology is tested in a real case study.

The Saint Louis River Idea-Slam crowd sourcing good ideas ...

EPA Pesticide Factsheets

As part of the 2017 Saint Louis River Summit, we propose hosting an “Idea-Slam” using software originally developed by the U.S. Consumer Financial Protection Bureau. Idea-box is an open source online app/website used to collect and surface ideas from members of an organization, or the public in general. Using the app, users login, view a request or challenge for new ideas, can submit their own ideas and/or view, comment and vote on other previously submitted ideas. Initially we will start with three idea request or “challenges” as listed below. The first will be run prior to the Summit to help generate additional challenges that might be added for the summit depending on the results. Initial Idea Challenges:1. (Prior to summit) If you could ask a large group of Saint Louis River focused scientist, stakeholders, managers, politicians and the public a question about the SLR, what would you ask?2. How might we better engage students and educators with the Saint Louis River?3. How might we employ citizen science for the Saint Louis River?The Idea-box app will be available for users two weeks before the Saint Louis Summit. We will e-mail previous summit participants and others an invitation to participate in “The Saint Louis River Idea-Slam” with clear instruction on how to proceed. During the morning of the first day at the Saint Louis Summit we will make a brief announcement about the Idea-Slam (< 2min.), and invite everyone to participate.

Cryogenic Refractive Indices of S-LAH55, S-LAH55V, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14 Glasses

NASA Technical Reports Server (NTRS)

Miller, Kevin H.; Quijada, Manuel A.; Leviton, Doug

2015-01-01

The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder, whose principal goal is to detect small planets with bright host starts in the solar neighborhood. The TESS payload consists of four identical cameras with seven optical elements each that include various types of Ohara glass substrates. The successful implementation both panchromatic and thermal lens assembly designs for these cameras requires a fairly accurate (up to 1E-6) knowledge of the temperature and wavelength dependence of the refractive index in the wavelength and temperature range of operation. Hence, this paper is devoted to report on measurements of the refractive index over the wavelength range of 0.42-1.15 um and temperature range of 110-310 K for the following Ohara glasses: S-LAH55, S-LAH55V, SLAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14. The measurements were performed utilizing the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at NASA's Goddard Space Flight Center. A dense coverage of the absolute refractive index for the title substrates in the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dn/dT) and dispersion relation (dn/d lambda) as a function of wavelength and temperature. A comparison of the measured indices with literature values, specifically the temperature-dependent refractive indices of S-PHM52 and S-TIH14, will be presented.

Patients as teachers, medical students as filmmakers: the video slam, a pilot study.

PubMed

Shapiro, Dan; Tomasa, Lynne; Koff, Nancy Alexander

2009-09-01

In 2006-2007 and 2007-2008, the authors pilot-tested a filmmaking project, (medical students filmed patients) to assess the project's potential to teach about the challenges of living with serious chronic illness. Two years of second-year medical students (N = 32) from The University of Arizona, working in groups of two or three, were paired with patients and filmed multiple home visits during eight months. Students edited their films to 7 to 10 minutes and added transitions, titles, and music. A mixed audience of students and faculty viewed the resulting 12 films in a "Video Slam." Faculty also used the films in the formal curriculum to illustrate teaching points related to chronic illness. Student filmmakers, on average, made 4.4 visits, collected 5.6 hours of film, and edited for 26.6 hours. Students reported that the project affected what they planned to cover in clinic visits, increased their plans to involve patients in care, enhanced their appreciation for patient-centered care, improved their knowledge of community resources, improved their understanding of allied health professionals' roles, and taught them about patients' innovative adaptations. Overall, students rated the project highly for its impact on their education (mean = 4.52 of 5). Student and faculty viewers of the films (N = 74) found the films compelling (mean = 4.95 of 5) and informative (mean = 4.93 of 5). The authors encountered the ethical dilemmas of deciding who controls the patients' recorded stories and navigating between patient anonymity/confidentiality and allowing patients to use their stories to teach.

Development of Kinematic 3D Laser Scanning System for Indoor Mapping and As-Built BIM Using Constrained SLAM

PubMed Central

Jung, Jaehoon; Yoon, Sanghyun; Ju, Sungha; Heo, Joon

2015-01-01

The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM). The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM) technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m) according to the guidelines of the General Services Administration for BIM accuracy. PMID:26501292

Automated Inference of Chemical Discriminants of Biological Activity.

PubMed

Raschka, Sebastian; Scott, Anne M; Huertas, Mar; Li, Weiming; Kuhn, Leslie A

2018-01-01

Ligand-based virtual screening has become a standard technique for the efficient discovery of bioactive small molecules. Following assays to determine the activity of compounds selected by virtual screening, or other approaches in which dozens to thousands of molecules have been tested, machine learning techniques make it straightforward to discover the patterns of chemical groups that correlate with the desired biological activity. Defining the chemical features that generate activity can be used to guide the selection of molecules for subsequent rounds of screening and assaying, as well as help design new, more active molecules for organic synthesis.The quantitative structure-activity relationship machine learning protocols we describe here, using decision trees, random forests, and sequential feature selection, take as input the chemical structure of a single, known active small molecule (e.g., an inhibitor, agonist, or substrate) for comparison with the structure of each tested molecule. Knowledge of the atomic structure of the protein target and its interactions with the active compound are not required. These protocols can be modified and applied to any data set that consists of a series of measured structural, chemical, or other features for each tested molecule, along with the experimentally measured value of the response variable you would like to predict or optimize for your project, for instance, inhibitory activity in a biological assay or ΔG binding . To illustrate the use of different machine learning algorithms, we step through the analysis of a dataset of inhibitor candidates from virtual screening that were tested recently for their ability to inhibit GPCR-mediated signaling in a vertebrate.

Mechanochemical Association Reaction of Interfacial Molecules Driven by Shear.

PubMed

Khajeh, Arash; He, Xin; Yeon, Jejoon; Kim, Seong H; Martini, Ashlie

2018-05-29

Shear-driven chemical reaction mechanisms are poorly understood because the relevant reactions are often hidden between two solid surfaces moving in relative motion. Here, this phenomenon is explored by characterizing shear-induced polymerization reactions that occur during vapor phase lubrication of α-pinene between sliding hydroxylated and dehydroxylated silica surfaces, complemented by reactive molecular dynamics simulations. The results suggest that oxidative chemisorption of the α-pinene molecules at reactive surface sites, which transfers oxygen atoms from the surface to the adsorbate molecule, is the critical activation step. Such activation takes place more readily on the dehydroxylated surface. During this activation, the most strained part of the α-pinene molecules undergoes a partial distortion from its equilibrium geometry, which appears to be related to the critical activation volume for mechanical activation. Once α-pinene molecules are activated, association reactions occur between the newly attached oxygen and one of the carbon atoms in another molecule, forming ether bonds. These findings have general implications for mechanochemistry because they reveal that shear-driven reactions may occur through reaction pathways very different from their thermally induced counterparts and specifically the critical role of molecular distortion in such reactions.

Synthesis of new bioactive aminophosphonates and study of their antioxidant, anti-inflammatory and antibacterial activities as well the assessment of their toxicological activity

NASA Astrophysics Data System (ADS)

Damiche, Rebiha; Chafaa, Salah

2017-02-01

Two new categories of α-aminophosphonates molecules were synthesized and characterized by UV-Vis, IR, and NMR. Their spectral properties show a perfect convergence. Their biological activities were evaluated. Molecules 1a, 2a, and 1d present a greater antioxidant potential than BHT and vitamin C. The best anti-inflammatory activity is shown by the 2b molecule and that of 1a, 2a, and 2c molecules are closely comparable to that of diclofenac. The antibacterial activity of the synthesized compounds is significantly higher than the antibiotic amoxicillin. The hemolysis rate HR of compounds 1b, 1c, 2b, and 2c was lower than 5%.

CD44 in cancer progression: adhesion, migration and growth regulation.

PubMed

Marhaba, R; Zöller, M

2004-03-01

It is well established that the large array of functions that a tumour cell has to fulfil to settle as a metastasis in a distant organ requires cooperative activities between the tumour and the surrounding tissue and that several classes of molecules are involved, such as cell-cell and cell-matrix adhesion molecules and matrix degrading enzymes, to name only a few. Furthermore, metastasis formation requires concerted activities between tumour cells and surrounding cells as well as matrix elements and possibly concerted activities between individual molecules of the tumour cell itself. Adhesion molecules have originally been thought to be essential for the formation of multicellular organisms and to tether cells to the extracellular matrix or to neighbouring cells. CD44 transmembrane glycoproteins belong to the families of adhesion molecules and have originally been described to mediate lymphocyte homing to peripheral lymphoid tissues. It was soon recognized that the molecules, under selective conditions, may suffice to initiate metastatic spread of tumour cells. The question remained as to how a single adhesion molecule can fulfil that task. This review outlines that adhesion is by no means a passive task. Rather, ligand binding, as exemplified for CD44 and other similar adhesion molecules, initiates a cascade of events that can be started by adherence to the extracellular matrix. This leads to activation of the molecule itself, binding to additional ligands, such as growth factors and matrix degrading enzymes, complex formation with additional transmembrane molecules and association with cytoskeletal elements and signal transducing molecules. Thus, through the interplay of CD44 with its ligands and associating molecules CD44 modulates adhesiveness, motility, matrix degradation, proliferation and cell survival, features that together may well allow a tumour cell to proceed through all steps of the metastatic cascade.

Effects of Different Camera Motions on the Error in Estimates of Epipolar Geometry between Two Dimensional Images in Order to Provide a Framework for Solutions to Vision Based Simultaneous Localization and Mapping (SLAM)

DTIC Science & Technology

2007-09-01

the projective camera matrix (P) which is a 3x4 matrix that is represents both the intrinsic and extrinsic parameters of a camera. It is used to...K contains the intrinsic parameters of the camera and |R t⎡ ⎤⎣ ⎦ represents the extrinsic parameters of the camera. By definition, the extrinsic ... extrinsic parameters are known then the camera is said to be calibrated. If only the intrinsic parameters are known, then the projective camera can

Localization of a mobile laser scanner via dimensional reduction

NASA Astrophysics Data System (ADS)

Lehtola, Ville V.; Virtanen, Juho-Pekka; Vaaja, Matti T.; Hyyppä, Hannu; Nüchter, Andreas

2016-11-01

We extend the concept of intrinsic localization from a theoretical one-dimensional (1D) solution onto a 2D manifold that is embedded in a 3D space, and then recover the full six degrees of freedom for a mobile laser scanner with a simultaneous localization and mapping algorithm (SLAM). By intrinsic localization, we mean that no reference coordinate system, such as global navigation satellite system (GNSS), nor inertial measurement unit (IMU) are used. Experiments are conducted with a 2D laser scanner mounted on a rolling prototype platform, VILMA. The concept offers potential in being extendable to other wheeled platforms.

Foil system fatigue load environments for commercial hydrofoil operation

NASA Technical Reports Server (NTRS)

Graves, D. L.

1979-01-01

The hydrofoil fatigue loads environment in the open sea is examined. The random nature of wave orbital velocities, periods and heights plus boat heading, speed and control system design are considered in the assessment of structural fatigue requirements. Major nonlinear load events such as hull slamming and foil unwetting are included in the fatigue environment. Full scale rough water load tests, field experience plus analytical loads work on the model 929 Jetfoil commercial hydrofoil are discussed. The problem of developing an overall sea environment for design is defined. State of the art analytical approaches are examined.

Acceleration of planes segmentation using normals from previous frame

NASA Astrophysics Data System (ADS)

Gritsenko, Pavel; Gritsenko, Igor; Seidakhmet, Askar; Abduraimov, Azizbek

2017-12-01

One of the major problem in integration process of robots is to make them able to function in a human environment. In terms of computer vision, the major feature of human made rooms is the presence of planes [1, 2, 20, 21, 23]. In this article, we will present an algorithm dedicated to increase speed of a plane segmentation. The algorithm uses information about location of a plane and its normal vector to speed up the segmentation process in the next frame. In conjunction with it, we will address such aspects of ICP SLAM as performance and map representation.

Electrochemical Detection of the Molecules of Life

NASA Technical Reports Server (NTRS)

Thomson, Seamus; Quinn, Richard; Koehne, Jessica

2017-01-01

All forms of life on Earth contain cellular machinery that can transform and regulate chemical energy through metabolic pathways. These processes are oxidation-reduction reactions that are performed by four key classes of molecules: flavins, nicotinamaides, porphyrins, and quinones. By detecting the electrochemical interaction of these redox-active molecules with an electrode, a method of differentiating them by their class could be established and incorporated into future life-detecting missions. This body of work investigates the electrochemistry of ubiquitous molecules found in life and how they may be detected. Molecules can oxidise or reduce the surface of an electrode - giving or receiving electrons - and these interactions are represented by changes in current with respect to an applied voltage. This relationship varies with: electrolyte type and concentration, working electrode material, the redox-active molecule itself, and scan rate. Flavin adenine dinucleotide (FAD), riboflavin, nicotinamide adenine dinucleotide (NADH), and anthraquinone are all molecules found intracellularly in almost all living organisms. An organism-synthesised extracellular redox-active molecule, Plumbagin, was also selected as part of this study. The goal of this work is to detect these molecules in seawater and assess its application in searching for life on Ocean Worlds.

Methods for immobilizing nucleic acids on a gel substrate

DOEpatents

Mirzabekov, Andrei Darievich; Proudnikov, Dimitri Y.; Timofeev, Edward N.; Kochetkova, Svetlana V.; Florentiev, Vladimir L.; Shick, Valentine V.

1999-01-01

A method for labeling oligonucleotide molecules, and for immobilizing oligonucleotide and DNA molecules is provided comprising modifying the molecules to create a chemically active group, and contacting activated fluorescent dyes to the region. A method for preparing an immobilization substrate is also provided comprising modifying a gel to contain desired functional groups which covalently interact with certain moieties of the oligonucleotide molecules. A method for immobilizing biomolecules and other molecules within a gel by copolymerization of allyl-substituted oligonucleotides, DNA and proteins with acrylamide is also provided.

Profiling protein function with small molecule microarrays

PubMed Central

Winssinger, Nicolas; Ficarro, Scott; Schultz, Peter G.; Harris, Jennifer L.

2002-01-01

The regulation of protein function through posttranslational modification, local environment, and protein–protein interaction is critical to cellular function. The ability to analyze on a genome-wide scale protein functional activity rather than changes in protein abundance or structure would provide important new insights into complex biological processes. Herein, we report the application of a spatially addressable small molecule microarray to an activity-based profile of proteases in crude cell lysates. The potential of this small molecule-based profiling technology is demonstrated by the detection of caspase activation upon induction of apoptosis, characterization of the activated caspase, and inhibition of the caspase-executed apoptotic phenotype using the small molecule inhibitor identified in the microarray-based profile. PMID:12167675

Single-molecule imaging of DNA polymerase I (Klenow fragment) activity by atomic force microscopy

NASA Astrophysics Data System (ADS)

Chao, J.; Zhang, P.; Wang, Q.; Wu, N.; Zhang, F.; Hu, J.; Fan, C. H.; Li, B.

2016-03-01

We report a DNA origami-facilitated single-molecule platform that exploits atomic force microscopy to study DNA replication. We imaged several functional activities of the Klenow fragment of E. coli DNA polymerase I (KF) including binding, moving, and dissociation from the template DNA. Upon completion of these actions, a double-stranded DNA molecule was formed. Furthermore, the direction of KF activities was captured and then confirmed by shifting the KF binding sites on the template DNA.We report a DNA origami-facilitated single-molecule platform that exploits atomic force microscopy to study DNA replication. We imaged several functional activities of the Klenow fragment of E. coli DNA polymerase I (KF) including binding, moving, and dissociation from the template DNA. Upon completion of these actions, a double-stranded DNA molecule was formed. Furthermore, the direction of KF activities was captured and then confirmed by shifting the KF binding sites on the template DNA. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06544e

Protection against herbivores

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howe, Gregg A.; Chen, Hui

The present invention relates to genes, proteins and methods comprising molecules that alter amino acid levels. In one embodiment, the present invention relates to altering guanidino substrate hydrolysis activities in plants, arthropods and microorganisms using molecules within the arginase family and other molecules that alter an amino acid levels. In ones embodiment, the present invention relates to altering threonine substrate deamination and dehydration activities in plants, arthropods and microorganisms using molecules within the threonine deaminase family and other molecules that alter amino acid levels. In one embodiment, the present invention relates to using genes, proteins and methods comprising arginase ormore » threonine deaminase for altering the pathophysiology of plants, arthropods and microorganisms. In a preferred embodiment, the present invention relates to altering guanidino substrate hydrolysis activity in plants, arthropods, and microorganisms using arginase. In another preferred embodiment, the invention relates to altering threonine substrated deamination and dehydration activity in plants, arthropods, and microorganisms using threonine deaminase. In some embodiments, the invention related to overexpression and increased activity of arginase, threonine deaminase and a proteinase inhibitor.« less

Protection against herbivores

DOEpatents

Howe, Gregg A; Chen, Hui

2014-10-28

The present invention relates to genes, proteins and methods comprising molecules that alter amino acid levels. In one embodiment, the present invention relates to altering guanidino substrate hydrolysis activities in plants, arthropods and microorganisms using molecules within the arginase family and other molecules that alter an amino acid levels. In ones embodiment, the present invention relates to altering threonine substrate deamination and dehydration activities in plants, arthropods and microorganisms using molecules within the threonine deaminase family and other molecules that alter amino acid levels. In one embodiment, the present invention relates to using genes, proteins and methods comprising arginase or threonine deaminase for altering the pathophysiology of plants, arthropods and microorganisms. In a preferred embodiment, the present invention relates to altering guanidino substrate hydrolysis activity in plants, arthropods, and microorganisms using arginase. In another preferred embodiment, the invention relates to altering threonine substrated deamination and dehydration activity in plants, arthropods, and microorganisms using threonine deaminase. In some embodiments, the invention related to overexpression and increased activity of arginase, threonine deaminase and a proteinase inhibitor.

Anti AIDS drug design with the help of neural networks

NASA Astrophysics Data System (ADS)

Tetko, I. V.; Tanchuk, V. Yu.; Luik, A. I.

1995-04-01

Artificial neural networks were used to analyze and predict the human immunodefiency virus type 1 reverse transcriptase inhibitors. Training and control set included 44 molecules (most of them are well-known substances such as AZT, TIBO, dde, etc.) The biological activities of molecules were taken from literature and rated for two classes: active and inactive compounds according to their values. We used topological indices as molecular parameters. Four most informative parameters (out of 46) were chosen using cluster analysis and original input parameters' estimation procedure and were used to predict activities of both control and new (synthesized in our institute) molecules. We applied pruning network algorithm and network ensembles to obtain the final classifier and avoid chance correlation. The increasing of neural network generalization of the data from the control set was observed, when using the aforementioned methods. The prognosis of new molecules revealed one molecule as possibly active. It was confirmed by further biological tests. The compound was as active as AZT and in order less toxic. The active compound is currently being evaluated in pre clinical trials as possible drug for anti-AIDS therapy.

Probing the Role of Active Site Water in the Sesquiterpene Cyclization Reaction Catalyzed by Aristolochene Synthase.

PubMed

Chen, Mengbin; Chou, Wayne K W; Al-Lami, Naeemah; Faraldos, Juan A; Allemann, Rudolf K; Cane, David E; Christianson, David W

2016-05-24

Aristolochene synthase (ATAS) is a high-fidelity terpenoid cyclase that converts farnesyl diphosphate exclusively into the bicyclic hydrocarbon aristolochene. Previously determined crystal structures of ATAS complexes revealed trapped active site water molecules that could potentially interact with catalytic intermediates: water "w" hydrogen bonds with S303 and N299, water molecules "w1" and "w2" hydrogen bond with Q151, and a fourth water molecule coordinates to the Mg(2+)C ion. There is no obvious role for water in the ATAS mechanism because the enzyme exclusively generates a hydrocarbon product. Thus, these water molecules are tightly controlled so that they cannot react with carbocation intermediates. Steady-state kinetics and product distribution analyses of eight ATAS mutants designed to perturb interactions with active site water molecules (S303A, S303H, S303D, N299A, N299L, N299A/S303A, Q151H, and Q151E) indicate relatively modest effects on catalysis but significant effects on sesquiterpene product distributions. X-ray crystal structures of S303A, N299A, N299A/S303A, and Q151H mutants reveal minimal perturbation of active site solvent structure. Seven of the eight mutants generate farnesol and nerolidol, possibly resulting from addition of the Mg(2+)C-bound water molecule to the initially formed farnesyl cation, but no products are generated that would suggest enhanced reactivity of other active site water molecules. However, intermediate germacrene A tends to accumulate in these mutants. Thus, apart from the possible reactivity of Mg(2+)C-bound water, active site water molecules in ATAS are not directly involved in the chemistry of catalysis but instead contribute to the template that governs the conformation of the flexible substrate and carbocation intermediates.

Solvent dependence of the activation energy of attachment determined by single molecule observations of surfactant adsorption.

PubMed

Honciuc, Andrei; Baptiste, Denver Jn; Campbell, Ian P; Schwartz, Daniel K

2009-07-07

Single-molecule total internal reflection fluorescence microscopy was used to obtain real-time images of fluorescently labeled hexadecanoic (palmitic) acid molecules as they adsorbed at the interface between fused silica and three different solvents: hexadecane (HD), tetrahydrofuran (THF), and water. These solvents were chosen to explore the effect of solvent polarity on the activation energy associated with the attachment rate, i.e., the rate at which molecules were transferred to the surface from the near-surface layer. Direct counting of single-molecule events, made under steady-state conditions at extremely low coverage, provided direct, model-independent measurements of this attachment rate, in contrast with conventional ensemble-averaged methods, which are influenced by bulk transport and competing detachment processes. We found that the attachment rate increased with increasing temperature for all solvents. Arrhenius analyses gave activation energies of 5+/-2 kJ/mol for adsorption from HD, 10+/-2 kJ/mol for adsorption from THF, and 19+/-2 kJ/mol for adsorption from water. These energies increased systematically with the solvent polarity and, therefore, with the expected strength of the solvent-substrate interaction. We hypothesize that the adsorption of amphiphilic solute molecules from solution can be regarded as a competitive exchange between solute molecules and surface-bound solvent. In this scenario, adsorption is an activated process, and the activation energy for attachment is associated with the solvent-substrate interaction energy.

A Single Amino Acid Substitution in the v-Eyk Intracellular Domain Results in Activation of Stat3 and Enhances Cellular Transformation

PubMed Central

Besser, Daniel; Bromberg, Jacqueline F.; Darnell, James E.; Hanafusa, Hidesaburo

1999-01-01

The receptor tyrosine kinase Eyk, a member of the Axl/Tyro3 subfamily, activates the STAT pathway and transforms cells when constitutively activated. Here, we compared the potentials of the intracellular domains of Eyk molecules derived from c-Eyk and v-Eyk to transform rat 3Y1 fibroblasts. The v-Eyk molecule induced higher numbers of transformants in soft agar and stronger activation of Stat3; levels of Stat1 activation by the two Eyk molecules were similar. A mutation in the sequence Y933VPL, present in c-Eyk, to the v-Eyk sequence Y933VPQ led to increased activation of Stat3 and increased transformation efficiency. However, altering another sequence, Y862VNT, present in both Eyk molecules to F862VNT markedly decreased transformation without impairing Stat3 activation. These results indicate that activation of Stat3 enhances transformation efficiency and cooperates with another pathway to induce transformation. PMID:9891073

Unraveling helicase mechanisms one molecule at a time

PubMed Central

Rasnik, Ivan; Myong, Sua; Ha, Taekjip

2006-01-01

Recent years have seen an increasing number of biological applications of single molecule techniques, evolving from a proof of principle type to the more sophisticated studies. Here we compare the capabilities and limitations of different single molecule techniques in studying the activities of helicases. Helicases share a common catalytic activity but present a high variability in kinetic and phenomenological behavior, making their studies ideal in exemplifying the use of the new single molecule techniques to answer biological questions. Unexpected phenomena have also been observed from individual molecules suggesting extended or alternative functionality of helicases in vivo. PMID:16935883

SLAM, a Mathematica interface for SUSY spectrum generators

NASA Astrophysics Data System (ADS)

Marquard, Peter; Zerf, Nikolai

2014-03-01

We present and publish a Mathematica package, which can be used to automatically obtain any numerical MSSM input parameter from SUSY spectrum generators, which follow the SLHA standard, like SPheno, SOFTSUSY, SuSeFLAV or Suspect. The package enables a very comfortable way of numerical evaluations within the MSSM using Mathematica. It implements easy to use predefined high scale and low scale scenarios like mSUGRA or mhmax and if needed enables the user to directly specify the input required by the spectrum generators. In addition it supports an automatic saving and loading of SUSY spectra to and from a SQL data base, avoiding the rerun of a spectrum generator for a known spectrum. Catalogue identifier: AERX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERX_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 4387 No. of bytes in distributed program, including test data, etc.: 37748 Distribution format: tar.gz Programming language: Mathematica. Computer: Any computer where Mathematica version 6 or higher is running providing bash and sed. Operating system: Linux. Classification: 11.1. External routines: A SUSY spectrum generator such as SPheno, SOFTSUSY, SuSeFLAV or SUSPECT Nature of problem: Interfacing published spectrum generators for automated creation, saving and loading of SUSY particle spectra. Solution method: SLAM automatically writes/reads SLHA spectrum generator input/output and is able to save/load generated data in/from a data base. Restrictions: No general restrictions, specific restrictions are given in the manuscript. Running time: A single spectrum calculation takes much less than one second on a modern PC.

Robust and Accurate Image-Based Georeferencing Exploiting Relative Orientation Constraints

NASA Astrophysics Data System (ADS)

Cavegn, S.; Blaser, S.; Nebiker, S.; Haala, N.

2018-05-01

Urban environments with extended areas of poor GNSS coverage as well as indoor spaces that often rely on real-time SLAM algorithms for camera pose estimation require sophisticated georeferencing in order to fulfill our high requirements of a few centimeters for absolute 3D point measurement accuracies. Since we focus on image-based mobile mapping, we extended the structure-from-motion pipeline COLMAP with georeferencing capabilities by integrating exterior orientation parameters from direct sensor orientation or SLAM as well as ground control points into bundle adjustment. Furthermore, we exploit constraints for relative orientation parameters among all cameras in bundle adjustment, which leads to a significant robustness and accuracy increase especially by incorporating highly redundant multi-view image sequences. We evaluated our integrated georeferencing approach on two data sets, one captured outdoors by a vehicle-based multi-stereo mobile mapping system and the other captured indoors by a portable panoramic mobile mapping system. We obtained mean RMSE values for check point residuals between image-based georeferencing and tachymetry of 2 cm in an indoor area, and 3 cm in an urban environment where the measurement distances are a multiple compared to indoors. Moreover, in comparison to a solely image-based procedure, our integrated georeferencing approach showed a consistent accuracy increase by a factor of 2-3 at our outdoor test site. Due to pre-calibrated relative orientation parameters, images of all camera heads were oriented correctly in our challenging indoor environment. By performing self-calibration of relative orientation parameters among respective cameras of our vehicle-based mobile mapping system, remaining inaccuracies from suboptimal test field calibration were successfully compensated.

Sources of nitrogen and phosphorus emissions to Irish rivers and coastal waters: Estimates from a nutrient load apportionment framework.

PubMed

Mockler, Eva M; Deakin, Jenny; Archbold, Marie; Gill, Laurence; Daly, Donal; Bruen, Michael

2017-12-01

More than half of surface water bodies in Europe are at less than good ecological status according to Water Framework Directive assessments, and diffuse pollution from agriculture remains a major, but not the only, cause of this poor performance. Agri-environmental policy and land management practices have, in many areas, reduced nutrient emissions to water. However, additional measures may be required in Ireland to further decouple the relationship between agricultural productivity and emissions to water, which is of vital importance given on-going agricultural intensification. The Source Load Apportionment Model (SLAM) framework characterises sources of phosphorus (P) and nitrogen (N) emissions to water at a range of scales from sub-catchment to national. The SLAM synthesises land use and physical characteristics to predict emissions from point (wastewater, industry discharges and septic tank systems) and diffuse sources (agriculture, forestry, etc.). The predicted annual nutrient emissions were assessed against monitoring data for 16 major river catchments covering 50% of the area of Ireland. At national scale, results indicate that total average annual emissions to surface water in Ireland are over 2700tyr -1 of P and 82,000tyr -1 of N. The proportional contributions from individual sources show that the main sources of P are from municipal wastewater treatment plants and agriculture, with wide variations across the country related to local anthropogenic pressures and the hydrogeological setting. Agriculture is the main source of N emissions to water across all regions of Ireland. These policy-relevant results synthesised large amounts of information in order to identify the dominant sources of nutrients at regional and local scales, contributing to the national nutrient risk assessment of Irish water bodies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Cryogenic Refractive Indices of S-LAH55, S-LAH55V, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14 Glasses

NASA Technical Reports Server (NTRS)

Miller, Kevin H.; Quijada, Manuel A.; Leviton, Douglas B.

2015-01-01

The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder, whose principal goal is to detect small planets with bright host starts in the solar neighborhood. The TESS payload consists of four identical cameras and a Data Handling Unit (DHU) fitted with CCD detectors and associated electronics. Each camera consist of a lens assembly with seven optical elements that include various types of Ohara glass substrates. The successful implementation of a panchromatic and a thermal lens assembly design for these cameras requires a fairly accurate (up to 0.000001 (1e-6)) knowledge of the temperature- and wavelength-dependent of the refractive index in the wavelength and temperature range of operation. Hence, this paper is devoted to report on measurements of the refractive index over the wavelength range of 0.42-1.15 micrometers and temperature range of 110-300 K for the following Ohara glasses: S-LAH55, S-LAH55V, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14. The measurements were performed utilizing the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at NASA's Goddard Space Flight Center. A dense coverage of the absolute refractive index for all these substrates in the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dndT) and dispersion relation (dnd) as a function of wavelength and temperature. A comparison of the measured indices with literature values, specifically the temperature-dependent refractive indices of S-PHM52 and S-TIH14 reported by Yamamuro et al. [Yamamuro et al., Opt. Eng. 45(8), 083401 (2006)], will be presented.

Delayed Monocular SLAM Approach Applied to Unmanned Aerial Vehicles.

PubMed

Munguia, Rodrigo; Urzua, Sarquis; Grau, Antoni

2016-01-01

In recent years, many researchers have addressed the issue of making Unmanned Aerial Vehicles (UAVs) more and more autonomous. In this context, the state estimation of the vehicle position is a fundamental necessity for any application involving autonomy. However, the problem of position estimation could not be solved in some scenarios, even when a GPS signal is available, for instance, an application requiring performing precision manoeuvres in a complex environment. Therefore, some additional sensory information should be integrated into the system in order to improve accuracy and robustness. In this work, a novel vision-based simultaneous localization and mapping (SLAM) method with application to unmanned aerial vehicles is proposed. One of the contributions of this work is to design and develop a novel technique for estimating features depth which is based on a stochastic technique of triangulation. In the proposed method the camera is mounted over a servo-controlled gimbal that counteracts the changes in attitude of the quadcopter. Due to the above assumption, the overall problem is simplified and it is focused on the position estimation of the aerial vehicle. Also, the tracking process of visual features is made easier due to the stabilized video. Another contribution of this work is to demonstrate that the integration of very noisy GPS measurements into the system for an initial short period of time is enough to initialize the metric scale. The performance of this proposed method is validated by means of experiments with real data carried out in unstructured outdoor environments. A comparative study shows that, when compared with related methods, the proposed approach performs better in terms of accuracy and computational time.

Effects of a smoking ban on clozapine plasma concentrations in a nonsecure psychiatric unit.

PubMed

Gee, Siobhan H; Taylor, David M; Shergill, Sukhwinder S; Flanagan, Robert; MacCabe, James H

2017-02-01

Tobacco smoke is known to affect plasma levels of some drugs, including the antipsychotic clozapine. The effects of suddenly stopping smoking on patients who take clozapine can be severe, as plasma concentrations are expected to rapidly rise, potentially leading to toxicity. A ban on smoking at South London and the Maudsley NHS Foundation Trust (SLaM) was implemented in 2014, and this was expected to affect the plasma concentrations of clozapine for inpatients at the time. This study aimed to determine whether plasma concentrations of clozapine were affected, and additionally, in line with observations from other authors, whether levels of reported violence would also be affected. The smoking habits of all patients at SLaM who smoked and were prescribed clozapine were recorded both before and after the ban. The Glasgow Antipsychotic Side Effect Scale for Clozapine (GASS-C) scale was used to evaluate side-effect burden. Clozapine doses and plasma concentrations were also collected. In total, 31 patients were included in this study. The mean clozapine dose before the ban was 502 mg/day, and this did not change significantly after the ban. Similarly, there were no significant changes in clozapine or norclozapine plasma concentrations, or in GASS-C scores. There was no change in the amount of tobacco patients reported smoking before or after the ban. A modest but statistically significant reduction in violent incidences was observed. Our data suggest that a ban on smoking for patients taking clozapine on open wards at inpatient hospital sites had little impact on clozapine plasma concentrations, because patients continued to smoke tobacco if allowed to leave. Smoking bans may result in a reduction in violent incidences.

Transdiagnostic Risk Calculator for the Automatic Detection of Individuals at Risk and the Prediction of Psychosis: Second Replication in an Independent National Health Service Trust.

PubMed

Fusar-Poli, Paolo; Werbeloff, Nomi; Rutigliano, Grazia; Oliver, Dominic; Davies, Cathy; Stahl, Daniel; McGuire, Philip; Osborn, David

2018-06-12

The benefits of indicated primary prevention among individuals at Clinical High Risk for Psychosis (CHR-P) are limited by the difficulty in detecting these individuals. To overcome this problem, a transdiagnostic, clinically based, individualized risk calculator has recently been developed and subjected to a first external validation in 2 different catchment areas of the South London and Maudsley (SLaM) NHS Trust. Second external validation of real world, real-time electronic clinical register-based cohort study. All individuals who received a first ICD-10 index diagnosis of nonorganic and nonpsychotic mental disorder within the Camden and Islington (C&I) NHS Trust between 2009 and 2016 were included. The model previously validated included age, gender, ethnicity, age by gender, and ICD-10 index diagnosis to predict the development of any ICD-10 nonorganic psychosis. The model's performance was measured using Harrell's C-index. This study included a total of 13702 patients with an average age of 40 (range 16-99), 52% were female, and most were of white ethnicity (64%). There were no CHR-P or child/adolescent services in the C&I Trust. The C&I and SLaM Trust samples also differed significantly in terms of age, gender, ethnicity, and distribution of index diagnosis. Despite these significant differences, the original model retained an acceptable predictive performance (Harrell's C of 0.73), which is comparable to that of CHR-P tools currently recommended for clinical use. This risk calculator may pragmatically support an improved transdiagnostic detection of at-risk individuals and psychosis prediction even in NHS Trusts in the United Kingdom where CHR-P services are not provided.

Automatic Intra-Operative Stitching of Non-Overlapping Cone-Beam CT Acquisitions

PubMed Central

Fotouhi, Javad; Fuerst, Bernhard; Unberath, Mathias; Reichenstein, Stefan; Lee, Sing Chun; Johnson, Alex A.; Osgood, Greg M.; Armand, Mehran; Navab, Nassir

2018-01-01

Purpose Cone-Beam Computed Tomography (CBCT) is one of the primary imaging modalities in radiation therapy, dentistry, and orthopedic interventions. While CBCT provides crucial intraoperative information, it is bounded by a limited imaging volume, resulting in reduced effectiveness. This paper introduces an approach allowing real-time intraoperative stitching of overlapping and non-overlapping CBCT volumes to enable 3D measurements on large anatomical structures. Methods A CBCT-capable mobile C-arm is augmented with a Red-Green-Blue-Depth (RGBD) camera. An off-line co-calibration of the two imaging modalities results in co-registered video, infrared, and X-ray views of the surgical scene. Then, automatic stitching of multiple small, non-overlapping CBCT volumes is possible by recovering the relative motion of the C-arm with respect to the patient based on the camera observations. We propose three methods to recover the relative pose: RGB-based tracking of visual markers that are placed near the surgical site, RGBD-based simultaneous localization and mapping (SLAM) of the surgical scene which incorporates both color and depth information for pose estimation, and surface tracking of the patient using only depth data provided by the RGBD sensor. Results On an animal cadaver, we show stitching errors as low as 0.33 mm, 0.91 mm, and 1.72mm when the visual marker, RGBD SLAM, and surface data are used for tracking, respectively. Conclusions The proposed method overcomes one of the major limitations of CBCT C-arm systems by integrating vision-based tracking and expanding the imaging volume without any intraoperative use of calibration grids or external tracking systems. We believe this solution to be most appropriate for 3D intraoperative verification of several orthopedic procedures. PMID:29569728

Wild-Type Measles Viruses with Non-Standard Genome Lengths

PubMed Central

Bankamp, Bettina; Liu, Chunyu; Rivailler, Pierre; Bera, Jayati; Shrivastava, Susmita; Kirkness, Ewen F.; Bellini, William J.; Rota, Paul A.

2014-01-01

The length of the single stranded, negative sense RNA genome of measles virus (MeV) is highly conserved at 15,894 nucleotides (nt). MeVs can be grouped into 24 genotypes based on the highly variable 450 nucleotides coding for the carboxyl-terminus of the nucleocapsid protein (N-450). Here, we report the genomic sequences of 2 wild-type viral isolates of genotype D4 with genome lengths of 15,900 nt. Both genomes had a 7 nt insertion in the 3′ untranslated region (UTR) of the matrix (M) gene and a 1 nt deletion in the 5′ UTR of the fusion (F) gene. The net gain of 6 nt complies with the rule-of-six required for replication competency of the genomes of morbilliviruses. The insertions and deletion (indels) were confirmed in a patient sample that was the source of one of the viral isolates. The positions of the indels were identical in both viral isolates, even though epidemiological data and the 3 nt differences in N-450 between the two genomes suggested that the viruses represented separate chains of transmission. Identical indels were found in the M-F intergenic regions of 14 additional genotype D4 viral isolates that were imported into the US during 2007–2010. Viral isolates with and without indels produced plaques of similar size and replicated efficiently in A549/hSLAM and Vero/hSLAM cells. This is the first report of wild-type MeVs with genome lengths other than 15,894 nt and demonstrates that the length of the M-F UTR of wild-type MeVs is flexible. PMID:24748123

Data-mining of potential antitubercular activities from molecular ingredients of traditional Chinese medicines.

PubMed

Jamal, Salma; Scaria, Vinod

2014-01-01

Background. Traditional Chinese medicine encompasses a well established alternate system of medicine based on a broad range of herbal formulations and is practiced extensively in the region for the treatment of a wide variety of diseases. In recent years, several reports describe in depth studies of the molecular ingredients of traditional Chinese medicines on the biological activities including anti-bacterial activities. The availability of a well-curated dataset of molecular ingredients of traditional Chinese medicines and accurate in-silico cheminformatics models for data mining for antitubercular agents and computational filters to prioritize molecules has prompted us to search for potential hits from these datasets. Results. We used a consensus approach to predict molecules with potential antitubercular activities from a large dataset of molecular ingredients of traditional Chinese medicines available in the public domain. We further prioritized 160 molecules based on five computational filters (SMARTSfilter) so as to avoid potentially undesirable molecules. We further examined the molecules for permeability across Mycobacterial cell wall and for potential activities against non-replicating and drug tolerant Mycobacteria. Additional in-depth literature surveys for the reported antitubercular activities of the molecular ingredients and their sources were considered for drawing support to prioritization. Conclusions. Our analysis suggests that datasets of molecular ingredients of traditional Chinese medicines offer a new opportunity to mine for potential biological activities. In this report, we suggest a proof-of-concept methodology to prioritize molecules for further experimental assays using a variety of computational tools. We also additionally suggest that a subset of prioritized molecules could be used for evaluation for tuberculosis due to their additional effect against non-replicating tuberculosis as well as the additional hepato-protection offered by the source of these ingredients.

Data-mining of potential antitubercular activities from molecular ingredients of traditional Chinese medicines

PubMed Central

Jamal, Salma

2014-01-01

Background. Traditional Chinese medicine encompasses a well established alternate system of medicine based on a broad range of herbal formulations and is practiced extensively in the region for the treatment of a wide variety of diseases. In recent years, several reports describe in depth studies of the molecular ingredients of traditional Chinese medicines on the biological activities including anti-bacterial activities. The availability of a well-curated dataset of molecular ingredients of traditional Chinese medicines and accurate in-silico cheminformatics models for data mining for antitubercular agents and computational filters to prioritize molecules has prompted us to search for potential hits from these datasets. Results. We used a consensus approach to predict molecules with potential antitubercular activities from a large dataset of molecular ingredients of traditional Chinese medicines available in the public domain. We further prioritized 160 molecules based on five computational filters (SMARTSfilter) so as to avoid potentially undesirable molecules. We further examined the molecules for permeability across Mycobacterial cell wall and for potential activities against non-replicating and drug tolerant Mycobacteria. Additional in-depth literature surveys for the reported antitubercular activities of the molecular ingredients and their sources were considered for drawing support to prioritization. Conclusions. Our analysis suggests that datasets of molecular ingredients of traditional Chinese medicines offer a new opportunity to mine for potential biological activities. In this report, we suggest a proof-of-concept methodology to prioritize molecules for further experimental assays using a variety of computational tools. We also additionally suggest that a subset of prioritized molecules could be used for evaluation for tuberculosis due to their additional effect against non-replicating tuberculosis as well as the additional hepato-protection offered by the source of these ingredients. PMID:25081126

The oxidoreductase ERp57 efficiently reduces partially folded in preference to fully folded MHC class I molecules

PubMed Central

Antoniou, Antony N.; Ford, Stuart; Alphey, Magnus; Osborne, Andrew; Elliott, Tim; Powis, Simon J.

2002-01-01

The oxidoreductase ERp57 is an integral component of the peptide loading complex of major histocompatibility complex (MHC) class I molecules, formed during their chaperone-assisted assembly in the endoplasmic reticulum. Misfolded MHC class I molecules or those denied suitable peptides are retrotranslocated and degraded in the cytosol. The presence of ERp57 during class I assembly suggests it may be involved in the reduction of intrachain disulfides prior to retrotranslocation. We have studied the ability of ERp57 to reduce MHC class I molecules in vitro. Recombinant ERp57 specifically reduced partially folded MHC class I molecules, whereas it had little or no effect on folded and peptide-loaded MHC class I molecules. Reductase activity was associated with cysteines at positions 56 and 405 of ERp57, the N-terminal residues of the active CXXC motifs. Our data suggest that the reductase activity of ERp57 may be involved during the unfolding of MHC class I molecules, leading to targeting for degradation. PMID:12032078

The impact of increased body mass index on systemic lupus erythematosus: data from LUMINA, a multiethnic cohort (LUMINA XLVI) [corrected].

PubMed

Chaiamnuay, Sumapa; Bertoli, Ana M; Fernández, Mónica; Apte, Mandar; Vilá, Luis M; Reveille, John D; Alarcón, Graciela S

2007-06-01

The aim of this study was to examine the impact of an increased body mass index (BMI) on disease activity, damage accrual, fatigue, self-reported health-related quality of life (HRQOL), and fibromyalgia in patients with lupus using longitudinal data from LUMINA, a large multiethnic cohort. SLE patients (>/=4 ACR revised criteria), /=30 kg/m). An increased BMI was associated with older age, less social support, higher degree of helplessness, depression, more abnormal illness-related behaviors, poorer self-reported HRQOL, fatigue, and fibromyalgia, but not with disease activity or damage accrual by univariable analyses. In multivariable analyses, BMI was independently associated with fibromyalgia but not with disease activity, fatigue, or self-reported HRQOL. An increased BMI is independently associated with presence of fibromyalgia but not with disease activity, damage accrual, fatigue or self-reported quality of life in patients with SLE. Optimizing weight merits investigation to see if it can significantly impact this pervasive SLE-associated manifestation.

Effects of protonation state of Asp181 and position of active site water molecules on the conformation of PTP1B.

PubMed

Ozcan, Ahmet; Olmez, Elif Ozkirimli; Alakent, Burak

2013-05-01

In protein tyrosine phosphatase 1B (PTP1B), the flexible WPD loop adopts a closed conformation (WPDclosed ) in the active state of PTP1B, bringing the catalytic Asp181 close to the active site pocket, while WPD loop is in an open conformation (WPDopen ) in the inactive state. Previous studies showed that Asp181 may be protonated at physiological pH, and ordered water molecules exist in the active site. In the current study, molecular dynamics simulations are employed at different Asp181 protonation states and initial positions of active site water molecules, and compared with the existing crystallographic data of PTP1B. In WPDclosed conformation, the active site is found to maintain its conformation only in the protonated state of Asp181 in both free and liganded states, while Asp181 is likely to be deprotonated in WPDopen conformation. When the active site water molecule network that is a part of the free WPDclosed crystal structure is disrupted, intermediate WPD loop conformations, similar to that in the PTPRR crystal structure, are sampled in the MD simulations. In liganded PTP1B, one active site water molecule is found to be important for facilitating the orientation of Cys215 and the phosphate ion, thus may play a role in the reaction. In conclusion, conformational stability of WPD loop, and possibly catalytic activity of PTP1B, is significantly affected by the protonation state of Asp181 and position of active site water molecules, showing that these aspects should be taken into consideration both in MD simulations and inhibitor design. Copyright © 2013 Wiley Periodicals, Inc.

Arrhenius plot for a reaction catalyzed by a single molecule of β-galactosidase.

PubMed

Craig, Douglas B; Chase, Linden N

2012-02-21

The activity of a single enzyme molecule of Escherichia coli β-galactosidase was measured using a capillary electrophoresis continuous flow assay. As the enzyme molecule traversed the capillary the incubation temperature was increased from 27 to 37 °C, providing a continuous record of the change in rate with temperature. This data was used to develop a single enzyme molecule Arrhenius plot, from which the activation energy of the reaction was determined to be 31 kJ mol(-1).

Generating Focused Molecule Libraries for Drug Discovery with Recurrent Neural Networks

PubMed Central

2017-01-01

In de novo drug design, computational strategies are used to generate novel molecules with good affinity to the desired biological target. In this work, we show that recurrent neural networks can be trained as generative models for molecular structures, similar to statistical language models in natural language processing. We demonstrate that the properties of the generated molecules correlate very well with the properties of the molecules used to train the model. In order to enrich libraries with molecules active toward a given biological target, we propose to fine-tune the model with small sets of molecules, which are known to be active against that target. Against Staphylococcus aureus, the model reproduced 14% of 6051 hold-out test molecules that medicinal chemists designed, whereas against Plasmodium falciparum (Malaria), it reproduced 28% of 1240 test molecules. When coupled with a scoring function, our model can perform the complete de novo drug design cycle to generate large sets of novel molecules for drug discovery. PMID:29392184

Study of the Chemical Space of Selected Bacteriostatic Sulfonamides from an Information Theory Point of View.

PubMed

López-Rosa, Sheila; Molina-Espíritu, Moyocoyani; Esquivel, Rodolfo O; Soriano-Correa, Catalina; Dehesa, Jésus S

2016-12-05

The relative structural location of a selected group of 27 sulfonamide-like molecules in a chemical space defined by three information theory quantities (Shannon entropy, Fisher information, and disequilibrium) is discussed. This group is composed of 15 active bacteriostatic molecules, 11 theoretically designed ones, and para-aminobenzoic acid. This endeavor allows molecules that share common chemical properties through the molecular backbone, but with significant differences in the identity of the chemical substituents, which might result in bacteriostatic activity, to be structurally classified and characterized. This is performed by quantifying the structural changes on the electron density distribution due to different functional groups and number of electrons. The macroscopic molecular features are described by means of the entropy-like notions of spatial electronic delocalization, order, and uniformity. Hence, an information theory three-dimensional space (IT-3D) emerges that allows molecules with common properties to be gathered. This space witnesses the biological activity of the sulfonamides. Some structural aspects and information theory properties can be associated, as a result of the IT-3D chemical space, with the bacteriostatic activity of these molecules. Most interesting is that the active bacteriostatic molecules are more similar to para-aminobenzoic acid than to the theoretically designed analogues. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design, synthesis, and characterization of 2,2-bis(2,4-dinitrophenyl)-2-(phosphonatomethylamino)acetate as a herbicidal and biological active agent.

PubMed

Kumar, Vijay; Singh, Simranjeet; Singh, Rohit; Upadhyay, Niraj; Singh, Joginder

2017-10-01

The present study was designed to synthesize the bioactive molecule 2,2-bis(2,4-dinitrophenyl)-2-(phosphonatomethylamino)acetate ( 1 ), having excellent applications in the field of plant protection as a herbicide. Structure of newly synthesized molecule 1 was confirmed by using the elemental analysis, mass spectrometric, NMR, UV-visible, and FTIR spectroscopic techniques. To obtain better structural insights of molecule 1 , 3D molecular modeling was performed using the GAMESS programme. Microbial activities of 1 were checked against the pathogenic strains Aspergillus fumigatus (NCIM 902) and Salmonella typhimurium (NCIM 2501). Molecule 1 has shown excellent activities against fungal strain A. fumigates (35 μg/l) and bacterial strain S. typhimurium (25 μg/l). To check the medicinal significance of molecule 1 , interactions with bovine serum albumin (BSA) protein were checked. The calculated value of binding constant of molecule 1 -BSA complex was 1.4 × 10 6  M -1 , which were similar to most effective drugs like salicylic acid. More significantly, as compared to herbicide glyphosate, molecule 1 has exhibited excellent herbicidal activities, in pre- and post-experiments on three weeds; barnyard grass ( Echinochloa Crus ), red spranglitop ( Leptochloa filiformis ), and yellow nuts ( Cyperus Esculenfus ). Further, effects of molecule 1 on plant growth-promoting rhizobacterial (PGPR) strains were checked. More interestingly, as compared to glyphosate, molecule 1 has shown least adverse effects on soil PGPR strains including the Rhizobium leguminosarum (NCIM 2749), Pseudomonas fluorescens (NCIM 5096), and Pseudomonas putida (NCIM 2847).

Water-assisted dehalogenation of thionyl chloride in the presence of water molecules.

PubMed

Yeung, Chi Shun; Ng, Ping Leung; Guan, Xiangguo; Phillips, David Lee

2010-04-01

A second-order Møller-Plesset perturbation theory (MP2) and density functional theory (DFT) investigation of the dehalogenation reactions of thionyl chloride is reported, in which water molecules (up to seven) were explicitly involved in the reaction complex. The dehalogenation processes of thionyl chloride were found to be dramatically catalyzed by water molecules. The reaction rate became significantly faster as more water molecules became involved in the reaction complex. The dehalogenation processes can be reasonably simulated by the gas-phase water cluster models, which reveals that water molecules can help to solvate the thionyl chloride molecules and activate the release of the Cl(-) leaving group. The computed activation energies were used to compare the calculations to available experimental data.

Mutant alpha-synuclein overexpression mediates early proinflammatory activity.

PubMed

Su, Xiaomin; Federoff, Howard J; Maguire-Zeiss, Kathleen A

2009-10-01

Microglia provide immune surveillance for the brain through both the removal of cellular debris and protection against infection by microorganisms and "foreign" molecules. Upon activation, microglia display an altered morphology and increased expression of proinflammatory molecules. Increased numbers of activated microglia have been identified in a number of neurodegenerative diseases including Parkinson's disease (PD). What remains to be determined is whether activated microglia result from ongoing cell death or are involved in disease initiation and progression. To address this question we utilized a transgenic mouse model that expresses a mutated form of a key protein involved in Parkinson's disease, alpha-synuclein. Herein, we report an increase in activated microglia and proinflammatory molecules in 1-month-old transgenic mice well before cell death occurs in this model. Frank microglial activation is resolved by 6 months of age while a subset of proinflammatory molecules remain elevated for 12 months. Both tyrosine hydroxylase mRNA expression and alpha-synuclein protein are decreased in the striatum of older animals evidence of dystrophic neuritic projections. To determine whether mutated alpha-synuclein could directly activate microglia primary microglia-enriched cell cultures were treated with exogenous mutated alpha-synuclein. The data reveal an increase in activated microglia and proinflammatory molecules due to direct interaction with mutated alpha-synuclein. Together, these data demonstrate that mutated alpha-synuclein mediates a proinflammatory response in microglia and this activity may participate in PD pathogenesis.

Evaluation of terrestrial plants extracts for uranium sorption and characterization of potent phytoconstituents.

PubMed

Sharma, Sunita; Singh, Bikram; Thulasidas, S K; Kulkarni, Madhuri J; Natarajan, V; Manchanda, Vijay K

2016-01-01

Sorption capacity of four plants (Funaria hygrometrica, Musa acuminata, Brassica juncea and Helianthus annuus) extracts/fractions for uranium, a radionuclide was investigated by EDXRF and tracer studies. The maximum sorption capacity, i.e., 100% (complete sorption) was observed in case of Musa acuminata extract and fractions. Carbohydrate, proteins, phenolics and flavonoids contents in the active fraction (having maximum sorption capacity) were also determined. Further purification of the most active fraction provided three pure molecules, mannitol, sorbitol and oxo-linked potassium oxalate. The characterization of isolated molecules was achieved by using FTIR, NMR, GC-MS, MS-MS, and by single crystal-XRD analysis. Of three molecules, oxo-linked potassium oxalate was observed to have 100% sorption activity. Possible binding mechanism of active molecule with the uranyl cation has been purposed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Xuan; Deeb, Claire; Kostcheev, Sergei

We report a self-developing anisotropic gold/polymer hybrid nanosystem that precisely places dye molecules at the plasmonic hotspot of metal nanostructures for sensing and photonics applications. Unlike conventional molecule-particle configurations, the anisotropic hybrid nanosystem (AHN) introduces an anisotropic spatial distribution of dye-containing active medium. This allows us to precisely overlap the near-field spatial distribution with the active medium and rule out the contribution from the background molecules. This overlap effect selectively highlights the optical response of the molecules of interest, i.e., molecules located at the hotspots. Our AHN consists of gold nanodimers whose gaps have been filled with methylene blue molecules.more » They have been studied by plasmon-enhanced Raman spectroscopy as a probing tool. The AHN opens new doors not only for fundamental studies and photonics applications of molecule-particle interactions, but also for molecular trapping methods at the nanoscale.« less

Preparation of translationally cold neutral molecules.

PubMed

Di Domenicantonio, Giulia; Bertsche, Benjamin; Osterwalder, Andreas

2011-01-01

Efforts at EPFL to obtain translationally cold neutral molecules are described. Active deceleration of polar molecules is performed by confining the molecules in moving three-dimensional electrostatic traps, and by appropriately choosing the velocity of those traps. Alternatively, cold molecules can be obtained by velocity filtering. Here, the velocity of the molecules is not changed, but instead the cold molecules are extracted from a thermal sample by using the competition between the electrostatic force and the centrifugal force inside a bent electrostatic guide for polar molecules.

Probabilistic double guarantee kidnapping detection in SLAM.

PubMed

Tian, Yang; Ma, Shugen

2016-01-01

For determining whether kidnapping has happened and which type of kidnapping it is while a robot performs autonomous tasks in an unknown environment, a double guarantee kidnapping detection (DGKD) method has been proposed. The good performance of DGKD in a relative small environment is shown. However, a limitation of DGKD is found in a large-scale environment by our recent work. In order to increase the adaptability of DGKD in a large-scale environment, an improved method called probabilistic double guarantee kidnapping detection is proposed in this paper to combine probability of features' positions and the robot's posture. Simulation results demonstrate the validity and accuracy of the proposed method.

GPS free navigation inspired by insects through monocular camera and inertial sensors

NASA Astrophysics Data System (ADS)

Liu, Yi; Liu, J. G.; Cao, H.; Huang, Y.

2015-12-01

Navigation without GPS and other knowledge of environment have been studied for many decades. Advance technology have made sensors more compact and subtle that can be easily integrated into micro and hand-hold device. Recently researchers found that bee and fruit fly have an effectively and efficiently navigation mechanism through optical flow information and process only with their miniature brain. We present a navigation system inspired by the study of insects through a calibrated camera and other inertial sensors. The system utilizes SLAM theory and can be worked in many GPS denied environment. Simulation and experimental results are presented for validation and quantification.

Dependently Typed Programming with Domain-Specific Logics

DTIC Science & Technology

2011-02-28

van den Berg and Garner, 2010; Voevodsky, 2010). This work promises a new class of proof assistants that intrinsically support proof irrelevance, equal...InΣ (neuA⇐ neu ⊗ sem) neut : InΣ (semA⇐ neu) slam : InΣ (semA⇐ (∀6 neuC (sem ⊃ sem))) reifyenv : Vars Vars Type reifyenv Ψe Ψs = ([Ψs ] * (neuC...ϕ) = lam · reify (Ψe, , expC) (Ψs, , neuC) σ’ (ϕ [neuC ] ( neut · (. i0))) where σ’ : (reifyenv (Ψe, , expC) (Ψs, , neuC)) σ’ i0 = i0 σ’ (iS x) = iS

Advanced computer graphic techniques for laser range finder (LRF) simulation

NASA Astrophysics Data System (ADS)

Bedkowski, Janusz; Jankowski, Stanislaw

2008-11-01

This paper show an advanced computer graphic techniques for laser range finder (LRF) simulation. The LRF is the common sensor for unmanned ground vehicle, autonomous mobile robot and security applications. The cost of the measurement system is extremely high, therefore the simulation tool is designed. The simulation gives an opportunity to execute algorithm such as the obstacle avoidance[1], slam for robot localization[2], detection of vegetation and water obstacles in surroundings of the robot chassis[3], LRF measurement in crowd of people[1]. The Axis Aligned Bounding Box (AABB) and alternative technique based on CUDA (NVIDIA Compute Unified Device Architecture) is presented.

Diffusion and mobility of atomic particles in a liquid

NASA Astrophysics Data System (ADS)

Smirnov, B. M.; Son, E. E.; Tereshonok, D. V.

2017-11-01

The diffusion coefficient of a test atom or molecule in a liquid is determined for the mechanism where the displacement of the test molecule results from the vibrations and motion of liquid molecules surrounding the test molecule and of the test particle itself. This leads to a random change in the coordinate of the test molecule, which eventually results in the diffusion motion of the test particle in space. Two models parameters of interaction of a particle and a liquid are used to find the activation energy of the diffusion process under consideration: the gas-kinetic cross section for scattering of test molecules in the parent gas and the Wigner-Seitz radius for test molecules. In the context of this approach, we have calculated the diffusion coefficient of atoms and molecules in water, where based on experimental data, we have constructed the dependence of the activation energy for the diffusion of test molecules in water on the interaction parameter and the temperature dependence for diffusion coefficient of atoms or molecules in water within the models considered. The statistically averaged difference of the activation energies for the diffusion coefficients of different test molecules in water that we have calculated based on each of the presented models does not exceed 10% of the diffusion coefficient itself. We have considered the diffusion of clusters in water and present the dependence of the diffusion coefficient on the cluster size. The accuracy of the presented formulas for the diffusion coefficient of atomic particles in water is estimated to be 50%.

Measles virus: Background and oncolytic virotherapy.

PubMed

Bhattacharjee, Sankhajit; Yadava, Pramod Kumar

2018-03-01

Measles is a highly transmissible disease caused by measles virus and remains a major cause of child mortality in developing countries. Measles virus nucleoprotein (N) encapsidates the RNA genome of the virus for providing protection from host cell endonucleases and for specific recognition of viral RNA as template for transcription and replication. This protein is over-expressed at the time of viral replication. The C-terminal of N protein is intrinsically disordered, which enables this protein to interact with several host cell proteins. It was previously proved in our laboratory that N expressing human cancerous cells undergo programmed cell death because of reactive oxygen species (ROS) generation as well as Caspase 3 activation. The phosphoprotein (P) along with N protein enclosed viral genomic RNA forming a ribonucleoprotein complex (RNP). It also establishes interaction with the large protein (L) i.e. viral RNA dependent RNA polymerase to ensure viral replication within host cells. The host cell receptors of this virus are CD46, SLAM/CD150 and PVRL4. Measles virus is latently oncotropic in nature and possesses oncolytic property by syncytia formation. We try to highlight the application of this property in developing a virotherapeutic vehicle.

Drosophila Bitter Taste(s)

PubMed Central

French, Alice; Ali Agha, Moutaz; Mitra, Aniruddha; Yanagawa, Aya; Sellier, Marie-Jeanne; Marion-Poll, Frédéric

2015-01-01

Most animals possess taste receptors neurons detecting potentially noxious compounds. In humans, the ligands which activate these neurons define a sensory space called “bitter”. By extension, this term has been used in animals and insects to define molecules which induce aversive responses. In this review, based on our observations carried out in Drosophila, we examine how bitter compounds are detected and if bitter-sensitive neurons respond only to molecules bitter to humans. Like most animals, flies detect bitter chemicals through a specific population of taste neurons, distinct from those responding to sugars or to other modalities. Activating bitter-sensitive taste neurons induces aversive reactions and inhibits feeding. Bitter molecules also contribute to the suppression of sugar-neuron responses and can lead to a complete inhibition of the responses to sugar at the periphery. Since some bitter molecules activate bitter-sensitive neurons and some inhibit sugar detection, bitter molecules are represented by two sensory spaces which are only partially congruent. In addition to molecules which impact feeding, we recently discovered that the activation of bitter-sensitive neurons also induces grooming. Bitter-sensitive neurons of the wings and of the legs can sense chemicals from the gram negative bacteria, Escherichia coli, thus adding another biological function to these receptors. Bitter-sensitive neurons of the proboscis also respond to the inhibitory pheromone, 7-tricosene. Activating these neurons by bitter molecules in the context of sexual encounter inhibits courting and sexual reproduction, while activating these neurons with 7-tricosene in a feeding context will inhibit feeding. The picture that emerges from these observations is that the taste system is composed of detectors which monitor different “categories” of ligands, which facilitate or inhibit behaviors depending on the context (feeding, sexual reproduction, hygienic behavior), thus considerably extending the initial definition of “bitter” tasting. PMID:26635553

Benzimidazoles diminish ERE transcriptional activity and cell growth in breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payton-Stewart, Florastina; Tilghman, Syreeta L.; Williams, LaKeisha G.

Highlights: • The methyl-substituted benzimidazole was more effective at inhibiting growth in MDA-MB 231 cells. • The naphthyl-substituted benzimidazole was more effective at inhibiting growth in MCF-7 cells than ICI. • The benzimidazole molecules demonstrated a dose-dependent reduction in ERE transcriptional activity. • The benzimidazole molecules had binding mode in ERα and ERβ comparable to that of the co-crystallized ligand. - Abstract: Estrogen receptors (ERα and ERβ) are members of the nuclear receptor superfamily. They regulate the transcription of estrogen-responsive genes and mediate numerous estrogen related diseases (i.e., fertility, osteoporosis, cancer, etc.). As such, ERs are potentially useful targets formore » developing therapies and diagnostic tools for hormonally responsive human breast cancers. In this work, two benzimidazole-based sulfonamides originally designed to reduce proliferation in prostate cancer, have been evaluated for their ability to modulate growth in estrogen dependent and independent cell lines (MCF-7 and MDA-MB 231) using cell viability assays. The molecules reduced growth in MCF-7 cells, but differed in their impact on the growth of MDA-MB 231 cells. Although both molecules reduced estrogen response element (ERE) transcriptional activity in a dose dependent manner, the contrasting activity in the MDA-MB-231 cells seems to suggest that the molecules may act through alternate ER-mediated pathways. Further, the methyl analog showed modest selectivity for the ERβ receptor in an ER gene expression array panel, while the naphthyl analog did not significantly alter gene expression. The molecules were docked in the ligand binding domains of the ERα-antagonist and ERβ-agonist crystal structures to evaluate the potential of the molecules to interact with the receptors. The computational analysis complimented the results obtained in the assay of transcriptional activity and gene expression suggesting that the molecules upregulate ERβ activity while down regulating that of ERα.« less

Olfactory receptor neuron profiling using sandalwood odorants.

PubMed

Bieri, Stephan; Monastyrskaia, Katherine; Schilling, Boris

2004-07-01

The mammalian olfactory system can discriminate between volatile molecules with subtle differences in their molecular structures. Efforts in synthetic chemistry have delivered a myriad of smelling compounds of different qualities as well as many molecules with very similar olfactive properties. One important class of molecules in the fragrance industry are sandalwood odorants. Sandalwood oil and four synthetic sandalwood molecules were selected to study the activation profile of endogenous olfactory receptors when exposed to compounds from the same odorant family. Dissociated rat olfactory receptor neurons were exposed to the sandalwood molecules and the receptor activation studied by monitoring fluxes in the internal calcium concentration. Olfactory receptor neurons were identified that were specifically stimulated by sandalwood compounds. These neurons expressed olfactory receptors that can discriminate between sandalwood odorants with slight differences in their molecular structures. This is the first study in which an important class of perfume compounds was analyzed for its ability to activate endogenous olfactory receptors in olfactory receptor neurons.

Vibrational spectroscopic and non-linear optical activity studies on nicotinanilide : A DFT approach

NASA Astrophysics Data System (ADS)

Premkumar, S.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

2015-06-01

The molecular structure of nicotinanilide was optimized by the DFT/B3LYP method with cc-pVTZ basis set using Gaussian 09 program. The first order hyperpolarizability of the molecule was calculated, which exhibits the higher nonlinear optical activity. The natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction, which leads to the higher nonlinear optical activity of the molecule. The Frontier molecular orbitals analysis of the molecule shows that the delocalization of electron density occurs within the molecule. The lower energy gap indicates that the hydrogen bond formation between the charged species. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation using the VEDA 4.0 program and the corresponding vibrational spectra were simulated. Hence, the nicotinanilide molecule can be a good candidate for second-order NLO material.

Inhibiting prolyl isomerase activity by hybrid organic-inorganic molecules containing rhodium(II) fragments.

PubMed

Coughlin, Jane M; Kundu, Rituparna; Cooper, Julian C; Ball, Zachary T

2014-11-15

A small molecule containing a rhodium(II) tetracarboxylate fragment is shown to be a potent inhibitor of the prolyl isomerase FKBP12. The use of small molecules conjugates of rhodium(II) is presented as a general strategy for developing new protein inhibitors based on distinct structural and sequence features of the enzyme active site. Copyright © 2014 Elsevier Ltd. All rights reserved.

Glutathione regulation of redox-sensitive signals in tumor necrosis factor-{alpha}-induced vascular endothelial dysfunction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsou, T.-C.; Yeh, S.C.; Tsai, F.-Y.

2007-06-01

We investigated the regulatory role of glutathione in tumor necrosis factor-alpha (TNF-{alpha})-induced vascular endothelial dysfunction as evaluated by using vascular endothelial adhesion molecule expression and monocyte-endothelial monolayer binding. Since TNF-{alpha} induces various biological effects on vascular cells, TNF-{alpha} dosage could be a determinant factor directing vascular cells into different biological fates. Based on the adhesion molecule expression patterns responding to different TNF-{alpha} concentrations, we adopted the lower TNF-{alpha} (0.2 ng/ml) to rule out the possible involvement of other TNF-{alpha}-induced biological effects. Inhibition of glutathione synthesis by L-buthionine-(S,R)-sulfoximine (BSO) resulted in down-regulations of the TNF-{alpha}-induced adhesion molecule expression and monocyte-endothelial monolayermore » binding. BSO attenuated the TNF-{alpha}-induced nuclear factor-kappaB (NF-{kappa}B) activation, however, with no detectable effect on AP-1 and its related mitogen-activated protein kinases (MAPKs). Deletion of an AP-1 binding site in intercellular adhesion molecule-1 (ICAM-1) promoter totally abolished its constitutive promoter activity and its responsiveness to TNF-{alpha}. Inhibition of ERK, JNK, or NF-{kappa}B attenuates TNF-{alpha}-induced ICAM-1 promoter activation and monocyte-endothelial monolayer binding. Our study indicates that TNF-{alpha} induces adhesion molecule expression and monocyte-endothelial monolayer binding mainly via activation of NF-{kappa}B in a glutathione-sensitive manner. We also demonstrated that intracellular glutathione does not modulate the activation of MAPKs and/or their downstream AP-1 induced by lower TNF-{alpha}. Although AP-1 activation by the lower TNF-{alpha} was not detected in our systems, we could not rule out the possible involvement of transiently activated MAPKs/AP-1 in the regulation of TNF-{alpha}-induced adhesion molecule expression.« less

A novel small molecule, Rosline, inhibits growth and induces caspase-dependent apoptosis in human lung cancer cells A549 through a reactive oxygen species-dependent mechanism.

PubMed

Zhao, Ting; Feng, Yang; Jin, Wenling; Pan, Hui; Li, Haizhou; Zhao, Yang

2016-06-01

Chemical screening using synthetic small molecule libraries has provided a huge amount of novel active molecules. It generates lead compound for drug development and brings focus on molecules for mechanistic investigations on many otherwise intangible biological processes. In this study, using non-small cell lung cancer cell A549 to screen against a structurally novel and diverse synthetic small molecule library of 2,400 compounds, we identified a molecule named rosline that has strong anti-proliferation activity on A549 cells with a 50% cell growth inhibitory concentration (IC50 ) of 2.87 ± 0.39 µM. We showed that rosline treatment increased the number of Annexin V-positive staining cell, as well as G2/M arrest in their cell cycle progression. Further, we have demonstrated that rosline induces a decrease of mitochondrial membrane potential (Δφm ) and an increase of caspases 3/7 and 9 activities in A549 cells, although having no effect on the activity of caspase 8. Moreover, we found that rosline could induce the production of reactive oxygen species (ROS) and inhibit the phosphorylation of signaling molecule Akt in A549 cells. Alternatively, an antioxidant N-acetyl-L-cysteine (NAC) significantly attenuated rosline's effects on the mitochondrial membrane potential, caspases 3/7 and 9 activities, cell viabilities and the phosphorylation of Akt. Our results demonstrated that ROS played an important role in the apoptosis of A549 cells induced by rosline. © 2016 International Federation for Cell Biology.

An atypical CNG channel activated by a single cGMP molecule controls sperm chemotaxis.

PubMed

Bönigk, Wolfgang; Loogen, Astrid; Seifert, Reinhard; Kashikar, Nachiket; Klemm, Clementine; Krause, Eberhard; Hagen, Volker; Kremmer, Elisabeth; Strünker, Timo; Kaupp, U Benjamin

2009-10-27

Sperm of the sea urchin Arbacia punctulata can respond to a single molecule of chemoattractant released by an egg. The mechanism underlying this extreme sensitivity is unknown. Crucial signaling events in the response of A. punctulata sperm to chemoattractant include the rapid synthesis of the intracellular messenger guanosine 3',5'-monophosphate (cGMP) and the ensuing membrane hyperpolarization that results from the opening of potassium-selective cyclic nucleotide-gated (CNGK) channels. Here, we use calibrated photolysis of caged cGMP to show that approximately 45 cGMP molecules are generated during the response to a single molecule of chemoattractant. The CNGK channel can respond to such small cGMP changes because it is exquisitely sensitive to cGMP and activated in a noncooperative fashion. Like voltage-activated Ca(v) and Na(v) channels, the CNGK polypeptide consists of four homologous repeat sequences. Disabling each of the four cyclic nucleotide-binding sites through mutagenesis revealed that binding of a single cGMP molecule to repeat 3 is necessary and sufficient to activate the CNGK channel. Thus, CNGK has developed a mechanism of activation that is different from the activation of other CNG channels, which requires the cooperative binding of several ligands and operates in the micromolar rather than the nanomolar range.

Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.

PubMed

Burns, Michael C; Sun, Qi; Daniels, R Nathan; Camper, DeMarco; Kennedy, J Phillip; Phan, Jason; Olejniczak, Edward T; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

2014-03-04

Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

Single-Molecule Electronic Measurements with Metal Electrodes

ERIC Educational Resources Information Center

Lindsay, Stuart

2005-01-01

A review of concepts like tunneling through a metal-molecule-metal-junction, contrast with electrochemical and optical-charge injection, strong-coupling limit, calculations of tunnel transport, electron transfer through Redox-active molecules is presented. This is followed by a discussion of experimental approaches for single-molecule measurements.

Raman Optical Activity of Biological Molecules

NASA Astrophysics Data System (ADS)

Blanch, Ewan W.; Barron, Laurence D.

Now an incisive probe of biomolecular structure, Raman optical activity (ROA) measures a small difference in Raman scattering from chiral molecules in right- and left-circularly polarized light. As ROA spectra measure vibrational optical activity, they contain highly informative band structures sensitive to the secondary and tertiary structures of proteins, nucleic acids, viruses and carbohydrates as well as the absolute configurations of small molecules. In this review we present a survey of recent studies on biomolecular structure and dynamics using ROA and also a discussion of future applications of this powerful new technique in biomedical research.

Giant optical activity of sugar in thin soap films.

PubMed

Emile, Janine; Emile, Olivier; Ghoufi, Aziz; Moréac, Alain; Casanova, Federico; Ding, Minxia; Houizot, Patrick

2013-10-15

We report on enhanced experimental optical activity measurements of thin soap films in the presence of sugar. This unusual optical activity is linked to the intramolecular chiral conformation of the glucose molecules at the air/liquid interface. Choosing sodium dodecylsulfate (SDS) as a model surfactant and glucose as model sugar, favorable interactions between the anionic group -OSO3(-)- and the glucose molecules are highlighted. This induces an interfacial anchoring of glucose molecules leading to a perturbing influence of the asymmetric chiral environment. Copyright © 2013 Elsevier Inc. All rights reserved.

The Alarmin Properties of DNA and DNA-associated Nuclear Proteins.

PubMed

Magna, Melinda; Pisetsky, David S

2016-05-01

The communication of cell injury and death is a critical element in host defense. Although immune cells can serve this function by elaborating cytokines and chemokines, somatic cells can repurpose nuclear macromolecules to function as damage-associated molecular patterns (DAMPs) or alarmins to exert similar activity. Among these molecules, DNA, high-mobility group box-1, and histone proteins can all act as DAMPs once they are in an extracellular location. This review describes current information on the role of the nuclear DAMPs, their translocation to the outside of cells, and pathways of activation after uptake into the inside of immune cells. MEDLINE and PubMed databases were searched for citations (1990-2016) in English related to the following terms: DAMPs, high-mobility group box-1, DNA, histones, cell death, danger, and immune activation. Selected articles with the most relevant studies were included for a more detailed consideration. Although nuclear molecules have important structural and genetic regulatory roles inside the cell nucleus, when released into the extracellular space during cell death, these molecules can acquire immune activity and serve as alarmins or DAMPs. Although apoptosis is generally considered the source of extracellular nuclear material, other cell death pathways such as necroptosis, NETosis, and pyroptosis can contribute to the release of nuclear molecules. Importantly, the release of nuclear DAMPs occurs with both soluble and particulate forms of these molecules. The activity of nuclear molecules may depend on posttranslational modifications, redox changes, and the binding of other molecules. Once in an extracellular location, nuclear DAMPs can engage the same pattern recognition receptors as do pathogen-associated molecular patterns. These interactions can activate immune cells and lead to cytokine and chemokine production. Among these receptors, internal receptors for DNA are key to the response to this molecule; the likely function of these internal sensors is the recognition of DNA from intracellular infection by bacteria or viruses. Activation of these receptors requires translocation of extracellular DNA into specialized compartments. In addition to nuclear DNA, mitochondrial DNA can also serve as a DAMP. The communication of cell injury and death is a critical element in host defense and involves the repurposing of nuclear molecules as immune triggers. As such, the presence of extracellular nuclear material can serve as novel biomarkers for conditions involving cell injury and death. Targeting of these molecules may also represent an important new approach to therapy. Published by Elsevier Inc.

Small molecule proteostasis regulators that reprogram the ER to reduce extracellular protein aggregation

PubMed Central

Plate, Lars; Cooley, Christina B; Chen, John J; Paxman, Ryan J; Gallagher, Ciara M; Madoux, Franck; Genereux, Joseph C; Dobbs, Wesley; Garza, Dan; Spicer, Timothy P; Scampavia, Louis; Brown, Steven J; Rosen, Hugh; Powers, Evan T; Walter, Peter; Hodder, Peter; Wiseman, R Luke; Kelly, Jeffery W

2016-01-01

Imbalances in endoplasmic reticulum (ER) proteostasis are associated with etiologically-diverse degenerative diseases linked to excessive extracellular protein misfolding and aggregation. Reprogramming of the ER proteostasis environment through genetic activation of the Unfolded Protein Response (UPR)-associated transcription factor ATF6 attenuates secretion and extracellular aggregation of amyloidogenic proteins. Here, we employed a screening approach that included complementary arm-specific UPR reporters and medium-throughput transcriptional profiling to identify non-toxic small molecules that phenocopy the ATF6-mediated reprogramming of the ER proteostasis environment. The ER reprogramming afforded by our molecules requires activation of endogenous ATF6 and occurs independent of global ER stress. Furthermore, our molecules phenocopy the ability of genetic ATF6 activation to selectively reduce secretion and extracellular aggregation of amyloidogenic proteins. These results show that small molecule-dependent ER reprogramming, achieved through preferential activation of the ATF6 transcriptional program, is a promising strategy to ameliorate imbalances in ER function associated with degenerative protein aggregation diseases. DOI: http://dx.doi.org/10.7554/eLife.15550.001 PMID:27435961

Pectins filled with LDH-antimicrobial molecules: preparation, characterization and physical properties.

PubMed

Gorrasi, Giuliana; Bugatti, Valeria; Vittoria, Vittoria

2012-06-05

Nanohybrids of layered double hydroxide (LDH) with intercalated active molecules: benzoate, 2,4-dichlorobenzoate, para-hydroxybenzoate and ortho-hydroxybenzoate, were incorporated into pectins from apples through high energy ball milling in the presence of water. Cast films were obtained and analysed. X-ray diffraction analysis showed a complete destructuration of all nanohybrids in the pectin matrix. Thermogravimetric analysis showed a better thermal resistance of pectin in the presence of fillers, especially para-hydroxybenzoate and ortho-hydroxybenzoate. Mechanical properties showed an improvement of elastic modulus in particular for LDH-para-hydroxybenzoate nanohybrid, due probably to a better interaction between pectin matrix and nanohybrid layers. Barrier properties (sorption and diffusion) to water vapour showed improvement in the dependence on the intercalated active molecule, the best improvement was achieved for composites containing para-hydroxybenzoate molecules, suggesting that the interaction between the filler phase and the polymer plays an important role in sorption and diffusion phenomena. Incorporation of these active molecules gave antimicrobial properties to the composite films giving opportunities in the field of active packaging. Copyright © 2012 Elsevier Ltd. All rights reserved.

Methods, microfluidic devices, and systems for detection of an active enzymatic agent

DOEpatents

Sommer, Gregory J; Hatch, Anson V; Singh, Anup K; Wang, Ying-Chih

2014-10-28

Embodiments of the present invention provide methods, microfluidic devices, and systems for the detection of an active target agent in a fluid sample. A substrate molecule is used that contains a sequence which may cleave in the presence of an active target agent. A SNAP25 sequence is described, for example, that may be cleaved in the presence of Botulinum Neurotoxin. The substrate molecule includes a reporter moiety. The substrate molecule is exposed to the sample, and resulting reaction products separated using electrophoretic separation. The elution time of the reporter moiety may be utilized to identify the presence or absence of the active target agent.

Cell-targetable DNA nanocapsules for spatiotemporal release of caged bioactive small molecules

NASA Astrophysics Data System (ADS)

Veetil, Aneesh T.; Chakraborty, Kasturi; Xiao, Kangni; Minter, Myles R.; Sisodia, Sangram S.; Krishnan, Yamuna

2017-12-01

Achieving triggered release of small molecules with spatial and temporal precision at designated cells within an organism remains a challenge. By combining a cell-targetable, icosahedral DNA-nanocapsule loaded with photoresponsive polymers, we show cytosolic delivery of small molecules with the spatial resolution of single endosomes in specific cells in Caenorhabditis elegans. Our technology can report on the extent of small molecules released after photoactivation as well as pinpoint the location at which uncaging of the molecules occurred. We apply this technology to release dehydroepiandrosterone (DHEA), a neurosteroid that promotes neurogenesis and neuron survival, and determined the timescale of neuronal activation by DHEA, using light-induced release of DHEA from targeted DNA nanocapsules. Importantly, sequestration inside the DNA capsule prevents photocaged DHEA from activating neurons prematurely. Our methodology can in principle be generalized to diverse neurostimulatory molecules.

Exploring sets of molecules from patents and relationships to other active compounds in chemical space networks

NASA Astrophysics Data System (ADS)

Kunimoto, Ryo; Bajorath, Jürgen

2017-09-01

Patents from medicinal chemistry represent a rich source of novel compounds and activity data that appear only infrequently in the scientific literature. Moreover, patent information provides a primary focal point for drug discovery. Accordingly, text mining and image extraction approaches have become hot topics in patent analysis and repositories of patent data are being established. In this work, we have generated network representations using alternative similarity measures to systematically compare molecules from patents with other bioactive compounds, visualize similarity relationships, explore the chemical neighbourhood of patent molecules, and identify closely related compounds with different activities. The design of network representations that combine patent molecules and other bioactive compounds and view patent information in the context of current bioactive chemical space aids in the analysis of patents and further extends the use of molecular networks to explore structure-activity relationships.

Factors associated with disease expression patterns in systemic lupus erythematosus patients: results from LUMINA (LXXVII), a multiethnic US cohort.

PubMed

Ugarte-Gil, M F; Pimentel-Quiroz, V R; Vilá, L M; Reveille, J D; McGwin, G; Alarcón, G S

2017-05-01

Objective The objective of this study was to determine the association of disease expression patterns with demographic and clinical characteristics in SLE. Methods Patients from a multi-ethnic SLE cohort were included. Disease expression patterns were defined as acute SLE and insidious SLE; this group was divided into those who accrued three ACR criteria and then accrued the fourth (insidious pattern A) and those who have one or two and then accrued four criteria (insidious pattern B). Disease activity was ascertained with the SLAM-R and disease damage with SLICC/ACR damage index. Variables were compared using analysis of variance for numeric variables and χ 2 for categorical variables. Multivariable analyses adjusting for possible confounders were performed. Results Six hundred and forty patients were included; the most frequent pattern was the insidious pattern B, with 415 (64.8%) patients, followed by the acute SLE group with 115 (18.0%) and the insidious pattern A with 110 (17.2%) patients. Patients from the insidious pattern A were older at diagnosis (pattern A: 39.8 vs pattern B: 36.7 vs acute: 32.4 years; p < 0.0001), more educated (13.6 vs 13.1 vs 12.1; p = 0.0008) and with a less active disease at baseline (8.8 vs 9.2 vs 10.7; p = 0.0227). Caucasian and Hispanic (Puerto Rico) ethnicities were overrepresented in this group (40.0% vs 27.7% vs 19.1% and 18.2% vs 17.1% vs 9.6%; p = 0.0003). Conclusions More insidious onset is associated with older age, Caucasian ethnicity, higher level of education, and lower disease activity than those with acute onset. However, after multivariable analyses, disease activity was not associated with any disease expression pattern.

Small molecule SIRT1 activators for the treatment of aging and age-related diseases

PubMed Central

Hubbard, Basil P.; Sinclair, David A.

2014-01-01

Recent studies in mice have identified single molecules that can delay multiple diseases of aging and extend lifespan. In theory, such molecules could prevent dozens of diseases simultaneously, significantly extending healthy years of life. In this review we discuss recent advances, controversies, opportunities, and challenges surrounding the development of SIRT1 activators, molecules with the potential to delay aging and age-related diseases. Sirtuins comprise a family of NAD+-dependent deacylases that are central to the body’s response to diet and exercise. New studies indicate that both natural and synthetic sirtuin activating compounds (STACs) work via a common allosteric mechanism to stimulate sirtuin activity, thereby conferring broad health benefits in rodents, primates, and possibly humans. The fact that the two-thirds of people in the USA who consume multiple dietary supplements consume resveratrol, a SIRT1 activator, underscores the importance of understanding the biochemical mechanism, physiological effects, and safety of STACs. PMID:24439680

Site-Specific Measurement of Water Dynamics in the Substrate Pocket of Ketosteroid Isomerase Using Time-Resolved Vibrational Spectroscopy

PubMed Central

Jha, Santosh Kumar; Ji, Minbiao; Gaffney, Kelly J.; Boxer, Steven G.

2012-01-01

Little is known about the reorganization capacity of water molecules at the active sites of enzymes and how this couples to the catalytic reaction. Here, we study the dynamics of water molecules at the active site of a highly proficient enzyme, Δ5-3-ketosteroid isomerase (KSI), during a light-activated mimic of its catalytic cycle. Photo-excitation of a nitrile containing photo-acid, coumarin183 (C183), mimics the change in charge density that occurs at the active site of KSI during the first step of the catalytic reaction. The nitrile of C183 is exposed to water when bound to the KSI active site, and we used time-resolved vibrational spectroscopy as a site-specific probe to study the solvation dynamics of water molecules in the vicinity of the nitrile. We observed that water molecules at the active site of KSI are highly rigid, during the light-activated catalytic cycle, compared to the solvation dynamics observed in bulk water. Based upon this result we hypothesize that rigid water dipoles at the active site might help in the maintenance of the pre-organized electrostatic environment required for efficient catalysis. The results also demonstrate the utility of nitrile probes in measuring the dynamics of local (H-bonded) water molecules in contrast to the commonly used fluorescence methods which measure the average behavior of primary and subsequent spheres of solvation. PMID:22931297

Exploring biology with small organic molecules

PubMed Central

Stockwell, Brent R.

2011-01-01

Small organic molecules have proven to be invaluable tools for investigating biological systems, but there is still much to learn from their use. To discover and to use more effectively new chemical tools to understand biology, strategies are needed that allow us to systematically explore ‘biological-activity space’. Such strategies involve analysing both protein binding of, and phenotypic responses to, small organic molecules. The mapping of biological-activity space using small molecules is akin to mapping the stars — uncharted territory is explored using a system of coordinates that describes where each new feature lies. PMID:15602550

Method for sequencing nucleic acid molecules

DOEpatents

Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

2006-06-06

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Method for sequencing nucleic acid molecules

DOEpatents

Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

2006-05-30

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Lessons from isolable nickel(I) precursor complexes for small molecule activation.

PubMed

Yao, Shenglai; Driess, Matthias

2012-02-21

Small-molecule activation by transition metals is essential to numerous organic transformations, both biological and industrial. Creating useful metal-mediated activation systems often depends on stabilizing the metal with uncommon low oxidation states and low coordination numbers. This provides a redox-active metal center with vacant coordination sites well suited for interacting with small molecules. Monovalent nickel species, with their d(9) electronic configuration, are moderately strong one-electron reducing agents that are synthetically attractive if they can be isolated. They represent suitable reagents for closing the knowledge gap in nickel-mediated activation of small molecules. Recently, the first strikingly stable dinuclear β-diketiminate nickel(I) precursor complexes were synthesized, proving to be suitable promoters for small-molecule binding and activation. They have led to many unprecedented nickel complexes bearing activated small molecules in different reduction stages. In this Account, we describe selected achievements in the activation of nitrous oxide (N(2)O), O(2), the heavier chalcogens (S, Se, and Te), and white phosphorus (P(4)) through this β-diketiminatonickel(I) precursor species. We emphasize the reductive activation of O(2), owing to its promise in oxidation processes. The one-electron-reduced O(2) activation product, that is, the corresponding β-diketiminato-supported Ni-O(2) complex, is a genuine superoxonickel(II) complex, representing an important intermediate in the early stages of O(2) activation. It selectively acts as an oxygen-atom transfer agent, hydrogen-atom scavenger, or both towards exogenous organic substrates to yield oxidation products. The one-electron reduction of the superoxonickel(II) moiety was examined by using elemental potassium, β-diketiminatozinc(II) chloride, and β-diketiminatoiron(I) complexes, affording the first heterobimetallic complexes featuring a [NiO(2)M] subunit (M is K, Zn, or Fe). Through density functional theory (DFT) calculations, the geometric and electronic structures of these complexes were established and their distinctive reactivity, including the unprecedented monooxygenase-like activity of a bis(μ-oxo)nickel-iron complex, was studied. The studies have further led to other heterobimetallic complexes containing a [NiO(2)M] core, which are useful for understanding the influence of the heterometal on structure-reactivity relationships. The activation of N(2)O led directly to the hydrogen-atom abstraction product bis(μ-hydroxo)nickel(II) species and prevented isolation of any intermediate. In contrast, the activation of elemental S, Se, and Te with the same nickel(I) reagent furnished activation products with superchalcogenido E(2)(-) (E is S, Se, or Te) and dichalcogenido E(2)(2-) ligand in different activation stages. The isolable supersulfidonickel(II) subunit may serve as a versatile building block for the synthesis of heterobimetallic disulfidonickel(II) complexes with a [NiS(2)M] core. In the case of white phosphorus, the P(4) molecule has been coordinated to the nickel(I) center of dinuclear β-diketiminatonickel(I) precursor complexes; however, the whole P(4) subunit is a weaker electron acceptor than the dichalcogen ligands E(2), thus remaining unreduced. This P(4) binding mode is rare and could open new doors for subsequent functionalization of P(4). Our advances in understanding how these small molecules are bound to a nickel(I) center and are activated for further transformation offer promise for designing new catalysts. These nickel-containing complexes offer exceptional potential for nickel-mediated transformations of organic molecules and as model compounds for mimicking active sites of nickel-containing metalloenzymes.

Self-assembly of active colloidal molecules with dynamic function

NASA Astrophysics Data System (ADS)

Soto, Rodrigo; Golestanian, Ramin

2015-05-01

Catalytically active colloids maintain nonequilibrium conditions in which they produce and deplete chemicals and hence effectively act as sources and sinks of molecules. While individual colloids that are symmetrically coated do not exhibit any form of dynamical activity, the concentration fields resulting from their chemical activity decay as 1 /r and produce gradients that attract or repel other colloids depending on their surface chemistry and ambient variables. This results in a nonequilibrium analog of ionic systems, but with the remarkable novel feature of action-reaction symmetry breaking. We study solutions of such chemically active colloids in dilute conditions when they join up to form molecules via generalized ionic bonds and discuss how we can achieve structures with time-dependent functionality. In particular, we study a molecule that adopts a spontaneous oscillatory pattern of conformations and another that exhibits a run-and-tumble dynamics similar to bacteria. Our study shows that catalytically active colloids could be used for designing self-assembled structures that possess dynamical functionalities that are determined by their prescribed three-dimensional structures, a strategy that follows the design principle of proteins.

Inhibition mechanism of lanthanum ion on the activity of horseradish peroxidase in vitro

NASA Astrophysics Data System (ADS)

Guo, Shaofen; Wang, Lihong; Lu, Aihua; Lu, Tianhong; Ding, Xiaolan; Huang, Xiaohua

2010-02-01

In order to understand the inhibition mechanism of lanthanum ion (La 3+) on the activity of horseradish peroxidase (HRP), the effects of La 3+ on the activity, electron transfer and conformation of HRP in vitro were investigated by using cyclic voltammetry (CV), atomic force microscopy (AFM), circular dichroism (CD), high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that La 3+ can combine with the amide groups of the polypeptide chain in HRP molecule, forming the complex of La 3+ and HRP (La-HRP). The formation of the La-HRP complex causes the destruction of the native structure of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure extent of active center, Fe(III) of the porphyrin ring of HRP molecule. Thus, the direct electrochemical and catalytic activities of HRP are decreased. It is a possible inhibition mechanism of La 3+ on the activity of peroxidase.

Syntheses, Characterizations, and Applications of Molecular Metal Wires and Functional Nanomaterials

DTIC Science & Technology

2009-12-22

challenges Conductance of single molecules Concluding Remarks...values of single -molecule conductance for such pentaruthenium EMACs, other triruthenium and trirhodium EMACs (Dalton Trans. 2009, 2623) were obtained...a voltage-activated switch, or a single -molecule transistor. Among the molecules reported in this research field,1 EMACs2 are particularly

Angiogenesis mediated by soluble forms of E-selectin and vascular cell adhesion molecule-1

NASA Astrophysics Data System (ADS)

Koch, Alisa E.; Halloran, Margaret M.; Haskell, Catherine J.; Shah, Manisha R.; Polverini, Peter J.

1995-08-01

ENDOTHELIAL adhesion molecules facilitate the entry of leukocytes into inflamed tissues. This in turn promotes neovascularization, a process central to the progression of rheumatoid arthritis, tumour growth and wound repair1. Here we test the hypothesis that soluble endothelial adhesion molecules promote angiogenesis2á¤-4. Human recombinant soluble E-selectin and soluble vascular cell adhesion molecule-1 induced chemotaxis of human endothelial cells in vitro and were angiogenic in rat cornea. Soluble E-selectin acted on endothelial cells in part through a sialyl Lewis-X-dependent mechanism, while soluble vascular cell adhesion molecule-1 acted on endothelial cells in part through a very late antigen (VLA)-4 dependent mechanism. The chemotactic activity of rheumatoid synovial fluid for endothelial cells, and also its angiogenic activity, were blocked by antibodies to either soluble E-selectin or soluble vascular cell adhesion molecule-1. These results suggest a novel function for soluble endothelial adhesion molecules as mediators of angiogenesis.

Nonequilibrium Chemical Effects in Single-Molecule SERS Revealed by Ab Initio Molecular Dynamics Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, Sean A.; Aprà, Edoardo; Govind, Niranjan

2017-02-03

Recent developments in nanophotonics have paved the way for achieving significant advances in the realm of single molecule chemical detection, imaging, and dynamics. In particular, surface-enhanced Raman scattering (SERS) is a powerful analytical technique that is now routinely used to identify the chemical identity of single molecules. Understanding how nanoscale physical and chemical processes affect single molecule SERS spectra and selection rules is a challenging task, and is still actively debated. Herein, we explore underappreciated chemical phenomena in ultrasensitive SERS. We observe a fluctuating excited electronic state manifold, governed by the conformational dynamics of a molecule (4,4’-dimercaptostilbene, DMS) interacting withmore » a metallic cluster (Ag20). This affects our simulated single molecule SERS spectra; the time trajectories of a molecule interacting with its unique local environment dictates the relative intensities of the observable Raman-active vibrational states. Ab initio molecular dynamics of a model Ag20-DMS system are used to illustrate both concepts in light of recent experimental results.« less

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins.

PubMed

Martinez, Ana Flávia Canovas; de Almeida, Luís Gustavo; Moraes, Luiz Alberto Beraldo; Cônsoli, Fernando Luís

2017-06-27

The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted attention as a source of new bioactive molecules because these microbes are exposed to various selection pressures in their association with insects. Analytical techniques must be used to isolate and characterize new compounds, and sensitive analytical tools such as mass spectrometry and high-resolution chromatography are required to identify the least-abundant molecules. We used classical fermentation techniques combined with tandem mass spectrometry to prospect for insecticidal substances produced by the ant symbiont Streptomyces caniferus. Crude extracts from this bacterium showed low biological activity (less than 10% mortality) against the larval stage of the fall armyworm Spodoptera frugiperda. Because of the complexity of the crude extract, we used fractionation-guided bioassays to investigate if the low toxicity was related to the relative abundance of the active molecule, leading to the isolation of porphyrins as active molecules. Porphyrins are a class of photoactive molecules with a broad range of bioactivity, including insecticidal. The active fraction, containing a mixture of porphyrins, induced up to 100% larval mortality (LD 50  = 37.7 μg.cm -2 ). Tandem mass-spectrometry analyses provided structural information for two new porphyrin structures. Data on the availability of porphyrins in 67 other crude extracts of ant ectosymbionts were also obtained with ion-monitoring experiments. Insect-associated bacterial symbionts are a rich source of bioactive compounds. Exploring microbial diversity through mass-spectrometry analyses is a useful approach for isolating and identifying new compounds. Our results showed high insecticidal activity of porphyrin compounds. Applications of different experiments in mass spectrometry allowed the characterization of two new porphyrins.

Anti-Biofilm Activity of a Long-Chain Fatty Aldehyde from Antarctic Pseudoalteromonas haloplanktis TAC125 against Staphylococcus epidermidis Biofilm

PubMed Central

Casillo, Angela; Papa, Rosanna; Ricciardelli, Annarita; Sannino, Filomena; Ziaco, Marcello; Tilotta, Marco; Selan, Laura; Marino, Gennaro; Corsaro, Maria M.; Tutino, Maria L.; Artini, Marco; Parrilli, Ermenegilda

2017-01-01

Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis. PMID:28280714

Genome-Scale Architecture of Small Molecule Regulatory Networks and the Fundamental Trade-Off between Regulation and Enzymatic Activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reznik, Ed; Christodoulou, Dimitris; Goldford, Joshua E.

Metabolic flux is in part regulated by endogenous small molecules that modulate the catalytic activity of an enzyme, e.g., allosteric inhibition. In contrast to transcriptional regulation of enzymes, technical limitations have hindered the production of a genome-scale atlas of small molecule-enzyme regulatory interactions. Here, we develop a framework leveraging the vast, but fragmented, biochemical literature to reconstruct and analyze the small molecule regulatory network (SMRN) of the model organism Escherichia coli, including the primary metabolite regulators and enzyme targets. Using metabolic control analysis, we prove a fundamental trade-off between regulation and enzymatic activity, and we combine it with metabolomic measurementsmore » and the SMRN to make inferences on the sensitivity of enzymes to their regulators. By generalizing the analysis to other organisms, we identify highly conserved regulatory interactions across evolutionarily divergent species, further emphasizing a critical role for small molecule interactions in the maintenance of metabolic homeostasis.« less

Bioorthogonal cyclization-mediated in situ self-assembly of small-molecule probes for imaging caspase activity in vivo

NASA Astrophysics Data System (ADS)

Ye, Deju; Shuhendler, Adam J.; Cui, Lina; Tong, Ling; Tee, Sui Seng; Tikhomirov, Grigory; Felsher, Dean W.; Rao, Jianghong

2014-06-01

Directed self-assembly of small molecules in living systems could enable a myriad of applications in biology and medicine, and already this has been used widely to synthesize supramolecules and nano/microstructures in solution and in living cells. However, controlling the self-assembly of synthetic small molecules in living animals is challenging because of the complex and dynamic in vivo physiological environment. Here we employ an optimized first-order bioorthogonal cyclization reaction to control the self-assembly of a fluorescent small molecule, and demonstrate its in vivo applicability by imaging caspase-3/7 activity in human tumour xenograft mouse models of chemotherapy. The fluorescent nanoparticles assembled in situ were imaged successfully in both apoptotic cells and tumour tissues using three-dimensional structured illumination microscopy. This strategy combines the advantages offered by small molecules with those of nanomaterials and should find widespread use for non-invasive imaging of enzyme activity in vivo.

Structural, vibrational spectroscopic and nonlinear optical activity studies on 2-hydroxy- 3, 5-dinitropyridine: A DFT approach

NASA Astrophysics Data System (ADS)

Asath, R. Mohamed; Premkumar, S.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

2015-06-01

The conformational analysis was carried out for 2-Hydroxy- 3, 5-dinitropyridine molecule using potential energy surface scan and the most stable optimized conformer was predicted. The vibrational frequencies and Mulliken atomic charge distribution were calculated for the optimized geometry of the molecule using DFT/B3LYP cc-pVQZ basis set by Gaussian 09 Program. The vibrational frequencies were assigned on the basis of potential energy distribution calculation using VEDA 4.0 program. In the Frontier molecular orbitals analysis, the molecular reactivity, kinetic stability, intramolecular charge transfer studies and the calculation of ionization energy, electron affinity, global hardness, chemical potential, electrophilicity index and softness values of the title molecule were carried out. The nonlinear optical activity of the molecule was studied by means of first order hyperpolarizability, which was computed as 7.64 times greater than urea. The natural bond orbital analysis was performed to confirm the nonlinear optical activity of the molecule.

Genome-Scale Architecture of Small Molecule Regulatory Networks and the Fundamental Trade-Off between Regulation and Enzymatic Activity

DOE PAGES

Reznik, Ed; Christodoulou, Dimitris; Goldford, Joshua E.; ...

2017-09-12

Metabolic flux is in part regulated by endogenous small molecules that modulate the catalytic activity of an enzyme, e.g., allosteric inhibition. In contrast to transcriptional regulation of enzymes, technical limitations have hindered the production of a genome-scale atlas of small molecule-enzyme regulatory interactions. Here, we develop a framework leveraging the vast, but fragmented, biochemical literature to reconstruct and analyze the small molecule regulatory network (SMRN) of the model organism Escherichia coli, including the primary metabolite regulators and enzyme targets. Using metabolic control analysis, we prove a fundamental trade-off between regulation and enzymatic activity, and we combine it with metabolomic measurementsmore » and the SMRN to make inferences on the sensitivity of enzymes to their regulators. By generalizing the analysis to other organisms, we identify highly conserved regulatory interactions across evolutionarily divergent species, further emphasizing a critical role for small molecule interactions in the maintenance of metabolic homeostasis.« less

A Computational Study of the Rheology and Structure of Surfactant Covered Droplets

NASA Astrophysics Data System (ADS)

Maia, Joao; Boromand, Arman; Jamali, Safa

2015-11-01

The use of different types of surface-active agents is ubiquitous practice in different industrial applications ranging from cosmetic and food industries to polymeric nano-composite and blends. This allows stable multiphasic systems like foams and emulsions to be produced. Stability and shelf-life of those products are directly determined by the efficiency of the surfactant molecules. Although the effect of molecular configuration of the surface-active molecules on the planar interfaces has been studied both experimentally and computationally, it remains challenging to track the efficiency and effectiveness of different surfactant molecules on curved interfaces. In this study we address this gap by using Dissipative Particle Dynamics, to study the effectiveness and efficiency of different surfactant molecules (linear vs. branched) on a curved interface in equilibrium and far from equilibrium. In particular, we are interested to relate interfacial properties of the surface covered droplets and its dynamics to the molecular configuration of the surface active molecules under equilibrium and far from equilibrium condition.

Natural extracellular nanovesicles and photodynamic molecules: is there a future for drug delivery?

PubMed

Kusuzaki, Katsuyuki; Matsubara, Takao; Murata, Hiroaki; Logozzi, Mariantonia; Iessi, Elisabetta; Di Raimo, Rossella; Carta, Fabrizio; Supuran, Claudiu T; Fais, Stefano

2017-12-01

Photodynamic molecules represent an alternative approach for cancer therapy for their property (i) to be photo-reactive; (ii) to be not-toxic for target cells in absence of light; (iii) to accumulate specifically into tumour tissues; (iv) to be activable by a light beam only at the tumour site and (v) to exert cytotoxic activity against tumour cells. However, to date their clinical use is limited by the side effects elicited by systemic administration. Extracellular vesicles are endogenous nanosized-carriers that have been recently introduced as a natural delivery system for therapeutic molecules. We have recently shown the ability of human exosomes to deliver photodynamic molecules. Therefore, this review focussed on extracellular vesicles as a novel strategy for the delivery of photodynamic molecules at cancer sites. This completely new approach may enhance the delivery and decrease the toxicity of photodynamic molecules, therefore, represent the future for photodynamic therapy for cancer treatment.

Single Molecule Enzymology via Nanoelectronic Circuits

NASA Astrophysics Data System (ADS)

Collins, Philip

Traditional single-molecule techniques rely on fluorescence or force transduction to monitor conformational changes and biochemical activity. Recent demonstrations of single-molecule monitoring with electronic transistors are poised to add to the single-molecule research toolkit. The transistor-based technique is sensitive to the motion of single charged side chain residues and can transduce those motions with microsecond resolution, opening the doors to single-molecule enzymology with unprecedented resolution. Furthermore, the solid-state platform provides opportunities for parallelization in arrays and long-duration monitoring of one molecule's activity or processivity, all without the limitations caused by photo-oxidation or mutagenic fluorophore incorporation. This presentation will review some of these advantages and their particular application to DNA polymerase I processing single-stranded DNA templates. This research was supported financially by the NIH NCI (R01 CA133592-01), the NIH NIGMS (1R01GM106957-01) and the NSF (DMR-1104629 and ECCS-1231910).

A zinc-dependent epitope on the molecule of thymulin, a thymic hormone.

PubMed Central

Dardenne, M; Savino, W; Berrih, S; Bach, J F

1985-01-01

Thymulin is a nonapeptide hormone produced by thymic epithelial cells. Its biological activity is strictly dependent on the presence of the metal zinc in the molecule. Antithymulin monoclonal antibodies have been produced against either the synthetic (AS1) or the natural intraepithelial (AE1) molecule. These monoclonal antibodies were screened for their abilities to inhibit the zinc-dependent biological activity of the hormone and were shown to bind to thymic epithelial cells. By using biological and immunofluorescence assays, the two antibodies were shown to recognize exclusively the zinc-coupled thymulin molecule. Other antithymulin antibodies screened by RIA or ELISA (using a zinc-deprived substrate) recognized a zinc-independent epitope on the thymulin molecule. These data indicate the existence of a zinc-specific conformation on the thymulin molecule. They are in agreement with NMR studies showing that the zinc-containing hormone has a unique structure. Images PMID:2413455

Suppression of complement regulatory protein C1 inhibitor in vascular endothelial activation by inhibiting vascular cell adhesion molecule-1 action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Haimou; Qin, Gangjian; Liang, Gang

Increased expression of adhesion molecules by activated endothelium is a critical feature of vascular inflammation associated with the several diseases such as endotoxin shock and sepsis/septic shock. Our data demonstrated complement regulatory protein C1 inhibitor (C1INH) prevents endothelial cell injury. We hypothesized that C1INH has the ability of an anti-endothelial activation associated with suppression of expression of adhesion molecule(s). C1INH blocked leukocyte adhesion to endothelial cell monolayer in both static assay and flow conditions. In inflammatory condition, C1INH reduced vascular cell adhesion molecule (VCAM-1) expression associated with its cytoplasmic mRNA destabilization and nuclear transcription level. Studies exploring the underlying mechanismmore » of C1INH-mediated suppression in VCAM-1 expression were related to reduction of NF-{kappa}B activation and nuclear translocation in an I{kappa}B{alpha}-dependent manner. The inhibitory effects were associated with reduction of inhibitor I{kappa}B kinase activity and stabilization of the NF-{kappa}B inhibitor I{kappa}B. These findings indicate a novel role for C1INH in inhibition of vascular endothelial activation. These observations could provide the basis for new therapeutic application of C1INH to target inflammatory processes in different pathologic situations.« less

Carbon-doped boron nitride nanosheet as a promising catalyst for N2O reduction by CO or SO2 molecule: A comparative DFT study

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Saeidi, Nasibeh

2018-06-01

We report for the first time, the catalytic activity of the experimentally available carbon-doped boron nitride nanosheet (C-BNNS) towards the reduction of N2O in the presence of CO or SO2 molecule. According to our density functional theory calculations, C-doping can introduce high spin density into BN monolayer which is mainly localized over the C and its neighboring N atoms. The Hirshfeld charge density analysis reveals that the electron-rich C-BNNS acts as an electron donating support to activate N2O molecule which is an important step in the reduction of N2O. The N2O reduction reaction starts with the dissociative adsorption of N2O over the C-BNNS surface, yielding the N2 molecule and an activated oxygen moiety (Oads) adsorbed over the C atom. The reaction then proceeds via the elimination of Oads by a CO or SO2 molecule. The obtained low activation energies clearly indicate that the metal-free C-BNNS surface can be regarded as a highly active catalyst for the reduction of N2O. The results of this study may open new avenues in searching low cost and highly active BN-based catalysts for low temperature reduction of N2O.