A set of data supposed to give possible axioms for spacetimes with a sufficient number of isometries in spectral geometry is given. These data are shown to be sufficient to obtain 1+1 dimensional de Sitter spacetime. ...
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A set of data supposed to give possible axioms for spacetimes with a sufficient number of isometries in spectral geometry is given. These data are shown to be sufficient to obtain 1+1 dimensional de Sitter spacetime. The data rely at the moment somewhat on the guidance given by a required symmetry, in part to allow explicit calculations in a specific model. The framework applies also to the noncommutative case. Finite spectral triples are discussed as an example. (C) 2002 American Institute of Physics.
We produced monoclonal antibody NG1 that strongly binds growing axons in the developing nervous system of mice. This antibody intensely labeled the growth cone of cultured neurons. Although these immunostaining patter...
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We produced monoclonal antibody NG1 that strongly binds growing axons in the developing nervous system of mice. This antibody intensely labeled the growth cone of cultured neurons. Although these immunostaining patterns suggested the association of growing axons with the antigen recognized by this antibody, the antigen was identified as Nogo protein, an axonal repulsive factor isolated from the myelin. On the basis of this unexpected finding, we discuss the possible functions of Nogo in the developing nervous system. (C) 2002 Elsevier Science B.V. All rights reserved.
The receptor Roundabout-1 (Robo1) and its ligand Slit are known to influence axon guidance and central nervous system (CNS) patterning in both vertebrate and nonvertebrate systems. Although Robo-Slit interactions medi...
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The receptor Roundabout-1 (Robo1) and its ligand Slit are known to influence axon guidance and central nervous system (CNS) patterning in both vertebrate and nonvertebrate systems. Although Robo-Slit interactions mediate axon guidance in the Drosophila CNS, their role in establishing the early axon scaffold in the embryonic vertebrate brain remains unclear. We report here the identification and expression of a Xenopus Robo1 orthologue that is highly homologous to mammalian Robo1. By using overexpression studies and immunohistochemical and in situ hybridization techniques, we have investigated the role of Robo1 in the development of a subset of neurons and axon tracts in the Xenopus forebrain. Robo1 is expressed in forebrain nuclei and in neuroepithelial cells underlying the main axon tracts. Misexpression of Robo1 led to aberrant development of axon tracts as well as the ectopic differentiation of forebrain neurons. These results implicate Robo1 in both neuronal differentiation and axon guidance in embryonic vertebrate forebrain. (C) 2002 Wiley-Liss, Inc.
The Eph family of receptors and ligands has been implicated in a variety of developmental processes, including the provision of inhibitory guidance cues to developing nerve fibers. A unique property of the B class of ...
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The Eph family of receptors and ligands has been implicated in a variety of developmental processes, including the provision of inhibitory guidance cues to developing nerve fibers. A unique property of the B class of receptors is that they are able to phosphorylate ephrin-B ligands, allowing for bi-directional, or reverse signalling. While most of the studies to date have focused on central nerve fibers, little is known about the role of Eph molecules in guiding nerve fibers of the peripheral nervous system. In the present study, ephrin-B1 was found to be highly expressed on developing peripheral nerve fibers including auditory and vestibular (statoacoustic) and dorsal root ganglion nerve fibers. In vitro assays revealed that EphB-Fc receptors inhibited further growth of statoacoustic nerve fibers. In contrast, EphA7-Fc and ephrin-B2-Fc did not prevent further growth of SAG. Together, these results suggest a role for EphB receptors in providing guidance signals to ephrin-B1-positive SAG nerve fibers.
PURPOSE: We investigated the benefit of real-time guidance of interventional punctures by means of computed tomography fluoroscopy (CTF) compared with the conventional sequential acquisition guidance. MATERIAL AND MET...
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PURPOSE: We investigated the benefit of real-time guidance of interventional punctures by means of computed tomography fluoroscopy (CTF) compared with the conventional sequential acquisition guidance. MATERIAL AND METHODS: In a prospective randomized trial, 75 patients underwent either CTF-guided (group A, n = 50) or sequential CT-guided (group B, n = 25) punctures of thoracic (n = 29) or abdominal (n = 46) masses. CTF was performed on the CT machine (Somatom Plus 4 Power, Siemens Corp., Forchheim, Germany) equipped with the C.A.R.E. Vision application (tube voltage 120 kV, tube current 50 mA, rotational time 0.75 s, slice thickness 10 mm, 8 frames/s). RESULTS: The average procedure time showed a statistically significant difference between the two study groups (group A: 564 s, group B 795 s, P = 0.0032). The mean total mAs was 7089 mAs for the CTF and 4856 mAs for the sequential image-guided intervention, respectively. The sensitivity was 71% specificity 100% positive predictive value 100% and negative predictive value 60% for the CTF-guided puncture, and 68, 100, 100 and 50% for sequential CT, respectively. CONCLUSION: CTF guidance realizes a time-saving but increases the radiation exposure dosage. (C) 2002 The Royal College of Radiologists.
This work presents real time implementation algorithms of Simultaneous Localization and Map Building (SLAM) with emphasis to outdoor land vehicle applications in large environments. It presents the problematic of outd...
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This work presents real time implementation algorithms of Simultaneous Localization and Map Building (SLAM) with emphasis to outdoor land vehicle applications in large environments. It presents the problematic of outdoors navigation in areas with combination of feature and featureless regions. The aspect of feature detection and validation is investigated to reliably detect the predominant features in the environment. Aided SLAM algorithms are presented that incorporate absolute information in a consistent manner. The SLAM implementation uses the compressed filter algorithm to maintain the map with a cost proportional to number of landmarks in the local area. The information gathered in the local area requires a full SLAM update when the vehicle leaves the local area. Algorithms to reduce the full update computational cost are also presented. Finally, experimental results obtained with a standard vehicle running in unstructured outdoor environment are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
Due to its ubiquity in our environment (near or far remote) water is the most investigated liquid of the literature. Since the advent of molecular simulations in the sixties the key point of the theoretical studies on...
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Due to its ubiquity in our environment (near or far remote) water is the most investigated liquid of the literature. Since the advent of molecular simulations in the sixties the key point of the theoretical studies on water is the description of its force field. During the last three decades a cohort of model potentials have been published and tested by computer simulations. Our purpose is to appraise what have been accomplished during all these years and what deserves to be improved. In addition we attempt to give some guidance for future investigations. (C) 2002 Elsevier Science B.V. All rights reserved.
Purpose: Role expansion in radiography is linked to ethico-legal responsibilities and accountability. This paper clarifies the legal requirements, outlines professional guidelines, and suggests that role developments ...
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Introduction: Health-related quality-of-life (HRQL) can be defined as the impact of disease and treatment across the physical, psychological, social and somatic domains of functioning and well-being. Health-related qu...
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Introduction: Health-related quality-of-life (HRQL) can be defined as the impact of disease and treatment across the physical, psychological, social and somatic domains of functioning and well-being. Health-related quality-of-life measures are included in clinical trials of drug treatment to assess the impact of therapy on the patient's functioning. HRQL guidance could allow for use of this data in drug labeling and promotion. Objectives: The aim of our study was to provide recommendations with respect to regulatory issues important to the development of guidelines for HRQL research. Methods: The HRQL workshop was planned jointly by members of the Pharmaceutical Research and Manufacturers of America Health Outcomes Committee and the Division of Drug Marketing, Advertising, and Communications of the Food and Drug Administration. The workshop was limited to six regulatory issues related to HRQL research in clinical trials of pharmaceutical therapies. These six issues were: instrument selection and validation, study design, data analysis, HRQL and safety, clinical meaning, and promotional use. Before the meeting, a consensus was reached that HRQL does not measure, nor should it be used to measure, safety. Therefore, five work groups discussed HRQL issues and made recommendations. Results: Overall, the workshop recommended that HRQL measures be treated as any other clinical end point. The workshop recognized that research in HRQL methods is ongoing and that any guidance should be flexible to allow for changes in this developing research area. Conclusions: HRQL provides a patient perspective on the impact of disease and therapy on patients' daily life and functioning. Including HRQL information in promotion could be beneficial to decision making on the use of therapies. HRQL is a measure of effectiveness, not safety, and should be treated as any other clinical end point.
This work presents real time implementation algorithms of Simultaneous Localization and Map Building (SLAM) with emphasis to outdoor land vehicle applications in large environments. It presents the problematic of outd...
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This work presents real time implementation algorithms of Simultaneous Localization and Map Building (SLAM) with emphasis to outdoor land vehicle applications in large environments. It presents the problematic of outdoors navigation in areas with combination of feature and featureless regions. The aspect of feature detection and validation is investigated to reliably detect the predominant features in the environment. Aided SLAM algorithms are presented that incorporate absolute information in a consistent manner. The SLAM implementation uses the compressed filter algorithm to maintain the map with a cost proportional to number of landmarks in the local area. The information gathered in the local area requires a full SLAM update when the vehicle leaves the local area. Algorithms to reduce the full update computational cost are also presented. Finally, experimental results obtained with a standard vehicle running in unstructured outdoor environment are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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