1,722,928 research outputs found
JPET #166710 PIP BEHAVIORAL INDICES IN ANTIPSYCHOTIC DRUG DISCOVERY Running title: Antipsychotic drug discovery Corresponding Author: Statistics : Number of text pages : 23 Number of tables : 0
No full textABSTRACT Schizophrenia is characterized by three major symptom classes: positive symptoms, negative symptoms and cognitive deficits. Classical antipsychotics (phenothiazines, thioxanthines, butyophenones) are effective against positive symptoms but induce major side-effects, in particular extrapyramidal symptoms (EPS). The discovery of clozapine, which does not induce EPS and is thought effective against all three classes of symptom, has driven research for novel antipsychotics with a wider activity spectrum and lower EPS liability. To increase predictiveness, current efforts aim to develop translational models, where direct parallels can be drawn between the processes studied in animals and in man. The present paper reviews existing procedures in animals for their ability to predict compound efficacy and EPS liability in relation to their translational validity. Rodent models of positive symptoms include procedures related to dysfunction in central dopamine (DA), glutamatergic (N-methyl-D-aspartate, NMDA) and serotonin (5-hydroxytryptamine, 5-HT) neurotransmission. Procedures for evaluating negative symptoms include rodent models of anhedonia, affective flattening and diminished social interaction. Cognitive deficits can be assessed in rodent models of attention (prepulse inhibition) and of learning/memory (object and social recognition, Morris water maze and operant delayed alternation). The relevance of the conditioned avoidance response (CAR) is also discussed. A final section reviews procedures for assessing EPS liability, in particular parkinsonism (catalepsy in rodents), acute dystonia (purposeless chewing in rodents, dystonia in monkeys), akathisia (defecation in rodents) and tardive dyskinesia (long-term antipsychotic treatment in rodents and monkeys). It is concluded that, with notable exceptions (attention, learning /memory, EPS liability), current predictive models for antipsychotics fall short of clear translational validity
Preliminary study on potential of the jPET-D4 human brain scanner for small animal imaging
No full textOBJECTIVE: One trend in positron emission tomography (PET) instrumentation over the last decade has been the development of scanners dedicated to small animals such as rats and mice. Thicker crystals, which are necessary to obtain higher sensitivity, result in degraded spatial resolution in the peripheral field-of-view (FOV) owing to the parallax error. On the other hand, we are developing the jPET-D4, which is a dedicated human brain PET scanner that has a capability for depth-of-interaction (DOI) measurement. Although its crystal width is about twice that of commercially available small animal PET scanners, we expect the jPET-D4 to have a potential for small animal imaging by making full use of the DOI information. In this article, we investigate the jPET-D4's potential for small animal imaging by comparing it with the microPET Focus220, a state-of-the-art PET scanner dedicated to small animals.
\nMETHODS: The jPET-D4 uses four-layered GSO crystals measuring 2.9 mm x 2.9 mm x 7.5 mm, whereas the microPET Focus220 uses a single layer of LSO crystals measuring 1.5 mm x 1.5 mm x 10.0 mm. First, the absolute sensitivity, counting rate performance and spatial resolution of both scanners were measured. Next a small hot-rod phantom was used to compare their imaging performance. Finally, a rat model with breast tumors was imaged using the jPET-D4.
\nRESULTS: Thanks to the thicker crystals and the longer axial FOV, the jPET-D4 had more than four times higher sensitivity than the microPET Focus220. The noise equivalent counting-rate performance of the jPETD4 reached 1,024 kcps for a rat-size phantom, whereas that of the microPET Focus220 reached only 165 kcps. At the center of the FOV, the resolution was 1.7 mm for the microPET Focus220, whereas it was 3.2 mm for the jPET-D4. On the other hand, the difference of resolution became smaller at the off-center position because the radial resolution degraded faster for the microPET Focus220. The results of phantom imaging showed that the jPET-D4 was comparable to the microPET Focus220 at the off-center position even as the microPET Focus220 outperformed the jPET-D4 except for the peripheral FOV.
\nCONCLUSIONS: The jPET-D4 human brain PET scanner, which was designed to achieve not only high resolution but also high sensitivity by measuring DOI information, was proven to have a potential for small animal imaging.journal articl
jPET: un generador de casos de prueba sobre programas Java
No full textProyecto de Sistemas Informáticos (Facultad de Informática, Curso 2010-2011)PET es una herramienta ya existente para la generación de casos de prueba que recibe como entrada un código de bytes de Java y una selección entre los criterios de recubrimiento disponibles y obtiene como salida un
conjunto de casos de prueba (test-cases) que garantizan el recubrimiento seleccionado. Puesto que el código de bytes es una representación de bajo nivel del programa, la información inferida por PET es difícilmente interpretable
por el usuario. Esto en concreto impide la utilización de PET durante el proceso de desarrollo de software, área en la que el testing tiene un amplio campo de aplicación. El objetivo del presente proyecto es la extensión de PET para su uso sobre programas Java de alto nivel y su integración en el entorno de desarrollo integrado Eclipse, con el objetivo de poder usar los resultados obtenidos por PET durante el proceso de desarrollo de software. El presente proyecto, al que hemos nombrado jPET, hace especial hincapié en el tratamiento posterior de la información generada por PET con el objetivo de presentarla al usuario de una forma fácil de entender. jPET incorpora un visor de casos de prueba (test-case viewer) que puede mostrar
el contenido de la memoria antes de la ejecución (heap de entrada) y después de la ejecución de cada caso de prueba (heap de salida). jPET puede mostrar la traza de ejecución de un caso de prueba dado (i.e., la secuencia de instrucciones que el caso de prueba ejecutaría) de dos formas distintas: (1) marcando todas las instrucciones implicadas o (2) permitiendo al usuario reproducir la secuencia de instrucciones paso a paso usando la interfaz
de depuración de Eclipse. Por último, puede analizar sintácticamente precondiciones de métodos escritas en JML (Java modeling language) y usarlas para evitar la generación de casos de prueba poco interesantes. Las principales contribuciones del proyecto se han recogido en un artículo titulado Software testing using jPET [2] que tenemos previsto enviarlo próximamente a un congreso internacional.
[ABSTRAC]
PET is an existing test case generation tool that takes as input a Ja-va bytecode program and a selection of a coverage criteria (among those available in the system) and returns in the output a set of test-cases which ensure the selected coverage. As bytecode is a low-level representation of the program, the information obtained by PET is difficult to interpret by a non-expert user. This particularly prevents the use of PET during software
development, an area in which testing has a large application field. The goal of this pr oject is the extension of PET for its use on Java source programs and its integration within the Eclipse integrated development environment with the objective of being able to apply the results obtained by PET during sofware development.
This project, named jPET, puts special emphasis on advanced processing of the information generated by PET in order to display it to the user in an easy way to interpret. For this purpose, jPET incorporates a viewer of test cases (test-case viewer) that can display the contents of the memory before execution (heap entry) and after the execution of each test case (heap output). jPET can show the execution trace of a given test case (i.e.,the sequence of instructions that execute the test case) in two ways: (1) by marking all instructions involved or (2) by allowing the user to reproduce the sequence of instructions step by step using the Eclipse debugger interface. Finally, jPET can parse preconditions of methods written in JML (Java Modeling Language) and use them to avoid the generation of test cases which are not interesting. The main contributions of this project have been written in a paper
entitled Software testing using jPET [2] that will be submitted soon to an Internacional ConferenceDepto. de Sistemas Informáticos y ComputaciónFac. de InformáticaTRUEunpu
The jPET-D4: Imaging Performance of the 4-Layer Depth-of-Interaction PET Scanner
No full textThe jPET-D4 is a high-performance brain PET scanner which achieves not only high spatial resolution but also high scanner sensitivity by discriminating 4-layer depth-of-interaction (DOI) information. The scanner is designed to have 5 rings of 24 detector blocks each, and the detector block consists of 1,024 GSO crystals of 2.9 mm x 2.9 mm x 7.5 mm, which are arranged in 4 layers of 16 x 16 arrays. At this stage, one of the 5 block-detector rings has been assembled into the jPET-D4 gantry. In this paper, we investigate the imaging performance of the jPET-D4 prototype. In order to reduce computational cost while keeping the advantage of DOI information in iterative image reconstruction, we have proposed the DOI compression (DOIC) method which reduces data dimensions with suppressing resolution loss. We have also proposed an imaging system model optimized for the jPET-D4 which enables fast system matrix calculation while preserving image quality. These methods were applied to the real data of needle sources on a uniform background. The result shows that almost uniform spatial resolution of less than 3 mm is obtained over the field-of-view by using the 4-layer DOI information. The Hoffman 3D brain phantom was also measured to compare the jPET-D4 with the HR+ commercial scanner. The result clearly shows the excellent imaging performance of the jPET-D4. Two or more detector-rings are being assembled, and the first volunteer tests are being planned.IEEE 2005 Nuclear Science Symposium & Medical Imaging Conferenceconference objec
The jPET-D4 Image Reconstruction by the DOI Compression (DOIC) Method
No full textA high-performance brain PET scanner, jPET-D4, which provides depth-of-interaction (DOI) information, is under development. At this stage, one of the 5 block-detector rings has been assembled into the jPET-D4 gantry. In order to reduce computational cost while keeping the advantage of DOI information in image reconstruction, we have previously proposed a DOI compression (DOIC) method. In this paper, we apply real data of the jPET-D4 prototype to the DOIC method followed by the ML-EM with accurate system modeling.The 8th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicineconference objec
A First Performance Evaluation of A Novel Brain DOI-PET Scanner - jPET-D4
No full textA high-performance brain PET scanner, jPET-D4, is under development. This scanner is designed to achieve not only high spatial resolution but also high scanner sensitivity with depth-of-interaction (DOI) measurement using four-layered thin crystals. A pair of detector blocks and a coincidence circuit have been assembled into an experimental prototype. As a preliminary experiment, we have investigated the performance of jPET-D4 in inherent spatial resolution. In conclusions, first experimental measurements promise an excellent resolution performance of jPET-D4.Society of Nuclear Medicine's 51st Annual Meetingconference objec
UNIFORM RESOLUTION PERFORMANCE OF THE FOUR-LAYER DOI DETECTOR FOR A RODENT PET SCANNER: jPET-RD
No full textFor research studies in biomedical sciences, small animal PET scanners should be highly sensitive to allow the clarification of vital functions at the molecular level and imaging of gene expression. We are planning to develop a small animal PET scanner with a large solid angle, jPET-RD (for Rodents with DOI detectors). The jPET-RD is designed to achieve high sensitivity as well as high spatial resolution by the use of four-layer depth of interaction (DOI) information. Lu2(1-x)Y2xSiO5 (LYSO) is chosen as scintillator to get higher count rate and detection efficiency. In this paper, we evaluate energy, timing, and spatial resolution of a jPET-RD prototype detector.52nd Annual Meetingconference objec
Performance evaluation for 120 four-layer DOI block detectors of the jPET-D4
No full textThe jPET-D4 is a brain positron emission tomography (PET) scanner that we have developed to meet user demands for high sensitivity and high spatial resolution. For this scanner, we developed a four-layer depth-of-interaction (DOI) detector. The four-layer DOI detector is a key component for the jPET-D4, its performance has great influence on the overall system performance. Previously, we reported the original technique for encoding four-layer DOI. Here, we introduce the final design of the jPET-D4 detector and present the results of an investigation on uniformity in performance of the detector. The performance evaluation was done over the 120 DOI crystal blocks for the detectors, which are to be assembled into the jPET-D4 scanner. We also introduce the crystal assembly method, which is simple enough, even though each DOI crystal block is composed of 1,024 crystal elements. The jPET-D4 detector consists of four layers of 16 × 16 Gd2SiO5 (GSO) crystals and a 256-channel flat-panel position-sensitive photomultiplier tube (256ch FP-PMT). To identify scintillated crystals in the four-layer DOI detector, we use pulse shape discrimination and position discrimination on the two-dimensional (2D) position histogram. For pulse shape discrimination, two kinds of GSO crystals that show different scintillation decay time constants are used in the upper two and lower two layers, respectively. Proper reflector arrangement in the crystal block then allows the scintillated crystals to be identified in these two-layer groupings with two 2D position histograms. We produced the 120 DOI crystal blocks for the jPET-D4 system, and measured their characteristics such as the accuracy of pulse shape discrimination, energy resolution, and the pulse height of the full energy peak. The results show a satisfactory and uniform performance of the four-layer DOI crystal blocks; for example, misidentification rate in each GSO layer is <5% based on pulse shape discrimination, the averaged energy resolutions for the central four crystals of the first (farthest from the FP-PMT), second, third, and 4th layers are 15.7 ± 1.0, 15.8 ± 0.6, 17.7 ± 1.2, and 17.3 ± 1.4%, respectively, and variation in pulse height of the full energy peak among the four layers is <5% on average.journal articl
jPET 2.0: un generador automático de casos de prueba sobre programas Java
No full textProyecto de Sistemas Informáticos (Facultad de Informática, Curso 2011-2012)JPet lleva desarrollándose varios años a fin de convertirlo en una herramienta competitiva en el campo del software testing. Se encarga de obtener casos de prueba (test-cases) de código java que garanticen el recubrimiento óptimo del mismo. En su comienzo la forma en que jPet mostraba la información a los usuarios no era fácil de entender, lo que hacía que no fuera útil durante el desarrollo de software. En la actualidad, se ha solucionado este problema guardando la información necesaria de los casos de prueba en ficheros
.xml, mostrando al desarrollador de una manera más gráfica y
sencilla el trabajo realizado. La herramienta incorpora un visor en el que se puede comprobar el valor de los datos antes y después de la ejecución del código, así como la posibilidad de ver la traza de un caso de prueba en concreto.
En este proyecto vamos a ampliar jPet añadiéndole la
funcionalidad de generar tests en código java a partir de los casos de prueba almacenados en los ficheros .xml. De esta manera, el desarrollador puede verificar el funcionamiento del código que pretende testear. Los tests contienen todo lo necesario para su ejecución en java, pero están escritos a modo de plantilla por lo que, aunque ayudan al desarrollador ahorrándole tiempo, es necesaria sucolaboración para que recobren sentido y pasen a ser tests válidos.
[ABSTRACT]
Jpet has become a competitive tool for software testing over
the years. It obtains java code test-cases that ensures an optimal coverage. From its beginnings, showing data and explaining it wasn’t an easy task, so Jpet was not useful for software developing. Nowadays, this problem has been solved by saving test-cases relevant data to .xml files, guiding software developers through a more graphic and comprehensive way of the work carried out by Jpet. It has a budget that may be interesting for developers, a graphic interface in which you can check data values before and after running the piece of software tested and see a concrete test-case tracing painted in a glowing green.
So now we are going to expand and continue this ongoing
project by adding functionality to generate java code unit tests (junits) using the test-cases above-mentioned. Those tests can run on Java but they are just templates. Although it will certainly help developers saving their time, they need to be accordingly modified to apply.Depto. de Sistemas Informáticos y ComputaciónFac. de InformáticaTRUEunpu
A Newly Identified Role for Superoxide in Inflammatory Pain JPET #64154 2 Running Title: Superoxide and hyperalgesia
No full text(C.M., V.M). JPET Fast Forward
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