Desenvolupament d'un servei criptogràfic per a la plataforma JADE

El present projecte de fi de carrera té com a objectiu principal el desenvolupament d’un servei criptogràfic per a la plataforma JADE, perquè es puguin implementar agents mòbils autoprotegits. Aquest objectiu s’ha aconseguit dotant les plataformes amb un parell de claus asimètriques i facilitant a l’agent funcions que utilitzen la clau privada de la plataforma entre un gran ventall de funcions criptogràfiques diferents.

Creació d'IP Cores en una plataforma NIOS: metodologia de disseny

NIOS és el processador que Altera empra en els seus dissenys SOC (System On Chip). Per tal de facilitar-ne el seu ús, Altera també proporciona una plataforma de desenvolupament SOPC (System On Programable Chip) que agilitza enormement el disseny d’aquests sistemes. Així doncs, aquest projecte està centrat en la definició metodològica per a la creació d'IP Cores en una plataforma NIOS.

Proposta de migració segura d'agents amb sol·licitud de classes sota demanda per a la plataforma JADE

Aquest projecte consisteix en la implementació d'una migració d'agents mòbils amb sol·licitud de classes sota demanda de manera segura per a la plataforma JADE. En aquest projecte hem desenvolupat dos protocols de control d'accés i autentificació sobre agents i/o plataformes. Però la línia central de desenvolupament d'aquest projecte radica en la creació d'un protocol de migració sota demanda d'agents. Hem implementat dues versions d'aquest protocol. La primera versió del protocol de migració es centra en la sol·licitud de classes sota demanda i la segona versió, per tal de millorar-ne el rendiment de la primera, emmagatzema les classes que ha demanat sota demanada en una cache de la plataforma.

Stem Cell Transplantation for Retinal Degenerations

Within the last few years, several reports have revealed that cell transplantation can be an effective way to replace lost neurons in the central nervous system (CNS) of patients affected with neurodegenerative diseases. Concerning the retina, the concept that newborn photoreceptors can integrate the retina and restore some visual functions was univocally demonstrated recently in the mouse eye (MacLaren et al. 2006) and remains to be achieved in human. These results pave the way to a standard approach in regenerative medicine aiming to replace lost photoreceptors. With the discovery of stem cells a great hope has appeared towards elaborating protocols to generate adequate cells to restore visual function in different retinal degeneration processes. Retinal stem cells (RSCs) are good candidates to repair the retina and are present throughout the retina development, including adulthood. However, neonatal mouse RSCs derived from the radial glia population have a different potential to proliferate and differentiate in comparison to adult RSCs. Moreover, we observed that adult mouse RSCs, depending on the culture conditions, have a marked tendency to transform, whereas neonatal RSCs show subtle chromosome abnormalities only after extensive expansion. These characteristics should help to identify the optimal cell source and culture conditions for cell transplantation studies. These results will be discussed in light of other studies using RSCs as well as embryonic stem cells. Another important factor to consider is the host environment, which plays a crucial role for cell integration and which was poorly studied in the normal and the diseased retina. Nonetheless, important results were recently generated to reconsider cell transplantation strategy. Perspectives to enhance cell integration by manipulating the environment will also be presented.

Results of An International Study of Quantitative BCR/ABL Assays Using Defined RNA Samples

Molecular monitoring of BCR/ABL transcripts by real time quantitative reverse transcription PCR (qRT-PCR) is an essential technique for clinical management of patients with BCR/ABL-positive CML and ALL. Though quantitative BCR/ABL assays are performed in hundreds of laboratories worldwide, results among these laboratories cannot be reliably compared due to heterogeneity in test methods, data analysis, reporting, and lack of quantitative standards. Recent efforts towards standardization have been limited in scope. Aliquots of RNA were sent to clinical test centers worldwide in order to evaluate methods and reporting for e1a2, b2a2, and b3a2 transcript levels using their own qRT-PCR assays. Total RNA was isolated from tissue culture cells that expressed each of the different BCR/ABL transcripts. Serial log dilutions were prepared, ranging from 100 to 10-5, in RNA isolated from HL60 cells. Laboratories performed 5 independent qRT-PCR reactions for each sample type at each dilution. In addition, 15 qRT-PCR reactions of the 10-3 b3a2 RNA dilution were run to assess reproducibility within and between laboratories. Participants were asked to run the samples following their standard protocols and to report cycle threshold (Ct), quantitative values for BCR/ABL and housekeeping genes, and ratios of BCR/ABL to housekeeping genes for each sample RNA. Thirty-seven (n=37) participants have submitted qRT-PCR results for analysis (36, 37, and 34 labs generated data for b2a2, b3a2, and e1a2, respectively). The limit of detection for this study was defined as the lowest dilution that a Ct value could be detected for all 5 replicates. For b2a2, 15, 16, 4, and 1 lab(s) showed a limit of detection at the 10-5, 10-4, 10-3, and 10-2 dilutions, respectively. For b3a2, 20, 13, and 4 labs showed a limit of detection at the 10-5, 10-4, and 10-3 dilutions, respectively. For e1a2, 10, 21, 2, and 1 lab(s) showed a limit of detection at the 10-5, 10-4, 10-3, and 10-2 dilutions, respectively. Log %BCR/ABL ratio values provided a method for comparing results between the different laboratories for each BCR/ABL dilution series. Linear regression analysis revealed concordance among the majority of participant data over the 10-1 to 10-4 dilutions. The overall slope values showed comparable results among the majority of b2a2 (mean=0.939; median=0.9627; range (0.399 - 1.1872)), b3a2 (mean=0.925; median=0.922; range (0.625 - 1.140)), and e1a2 (mean=0.897; median=0.909; range (0.5174 - 1.138)) laboratory results (Fig. 1-3)). Thirty-four (n=34) out of the 37 laboratories reported Ct values for all 15 replicates and only those with a complete data set were included in the inter-lab calculations. Eleven laboratories either did not report their copy number data or used other reporting units such as nanograms or cell numbers; therefore, only 26 laboratories were included in the overall analysis of copy numbers. The median copy number was 348.4, with a range from 15.6 to 547,000 copies (approximately a 4.5 log difference); the median intra-lab %CV was 19.2% with a range from 4.2% to 82.6%. While our international performance evaluation using serially diluted RNA samples has reinforced the fact that heterogeneity exists among clinical laboratories, it has also demonstrated that performance within a laboratory is overall very consistent. Accordingly, the availability of defined BCR/ABL RNAs may facilitate the validation of all phases of quantitative BCR/ABL analysis and may be extremely useful as a tool for monitoring assay performance. Ongoing analyses of these materials, along with the development of additional control materials, may solidify consensus around their application in routine laboratory testing and possible integration in worldwide efforts to standardize quantitative BCR/ABL testing.

Exploration of the visual system : Part 2. In vivo analysis methods : virtual-reality optomotor system, fundus examination and fluorescent angiography

The mouse has emerged as an animal model for many diseases. At IRO, we have used this animal to understand the development of many eye diseases and treatment of some of them. Precise evaluation of vision is a prerequisite for both these approaches. In this unit we describe three ways to measure vision: testing the optokinetic response, and evaluating the fundus by direct observation and by fluorescent angiography.

Multi-phase post-mortem CT angiography: development of a standardized protocol.

The objective of this work was to develop an easily applicable technique and a standardized protocol for high-quality post-mortem angiography. This protocol should (1) increase the radiological interpretation by decreasing artifacts due to the perfusion and by reaching a complete filling of the vascular system and (2) ease and standardize the execution of the examination. To this aim, 45 human corpses were investigated by post-mortem computed tomography (CT) angiography using different perfusion protocols, a modified heart-lung machine and a new contrast agent mixture, specifically developed for post-mortem investigations. The quality of the CT angiographies was evaluated radiologically by observing the filling of the vascular system and assessing the interpretability of the resulting images and by comparing radiological diagnoses to conventional autopsy conclusions. Post-mortem angiography yielded satisfactory results provided that the volumes of the injected contrast agent mixture were high enough to completely fill the vascular system. In order to avoid artifacts due to the post-mortem perfusion, a minimum of three angiographic phases and one native scan had to be performed. These findings were taken into account to develop a protocol for quality post-mortem CT angiography that minimizes the risk of radiological misinterpretation. The proposed protocol is easy applicable in a standardized way and yields high-quality radiologically interpretable visualization of the vascular system in post-mortem investigations.

Estudio e implementación de una autoridad de certificación distribuida

Aquest projecte presenta, en primer lloc, un estudi dels protocols de generació de claus criptogràfiques i autoritats de certificació distribuïdes més destacables desenvolupades fins a l'actualitat. Posteriorment, implementem un protocol, que toleri les errades, de generació distribuïda de claus RSA sense servidor de confiança, orientat a xarxes ad-hoc. El protocol necessita la participació conjunta de n nodes per generar un mòdul RSA (N = pq), un exponent d'encriptació públic i les particions de l'exponent privat d, seguint un esquema llindar (t, n).

Los repositorios electrónicos cooperativos de la Biblioteca Digital de Cataluña

Entre 1998 y 1999, el Consorcio de Bibliotecas Universitarias de Cataluña (CBUC) creó una nueva línea de trabajo: la Biblioteca Digital de Cataluña. Ésta nació con la finalidad de contratar información electrónica interdisciplinar para la comunidad universitaria e investigadora de las bibliotecas miembro del Consorcio. Casi al mismo tiempo, esta línea de trabajo se amplió con la vertiente de la información propia generada por esta comunidad y se empezó a trabajar con la definición e implementación de repositorios electrónicos cooperativos. Estos últimos serán el objeto de este estudio. Se analiza su evolución, su estado actual, la estrategia para conseguir la inclusión de documentos (políticas institucionales, comités científicos, etc.), su contenedor (programas, tecnología usada, protocolos, etc.) y su contenido (estándares utilizados, derechos de autor, preservación, etc.). Por último se reflexiona sobre las ventajas, extraídas de la propia experiencia, de estos repositorios electrónicos cooperativos.

Els dipòsits electrònics cooperatius de la Biblioteca Digital de Catalunya

Entre 1998 i 1999, el Consorci de Biblioteques Universitàries de Catalunya (CBUC) va crear una nova línia de treball: la Biblioteca Digital de Catalunya. Aquesta va néixer amb la finalitat de contractar informació electrònica interdisciplinar per a la comunitat universitària i investigadora dels membres del Consorci. Gairebé al mateix temps, aquesta línia de treball es va ampliar amb la vessant de la informació pròpia generada per aquesta comunitat i es va començar a treballar amb la definició i implementació dels dipòsits electrònics cooperatius. Aquests últims seran l'objecte d'estudi. S'analitza la seva evolució, el seu estat actual, l'estratègia per aconseguir la inclusió de documents (polítiques institucionals, comitès científics, etc.), el seu continent (programes, tecnologia usada, protocols, etc.) i el seu contingut (estàndards utilitzats, drets d'autor, preservació, etc.). Per últim es reflexiona sobre les avantatges, extretes de la pròpia experiència, d'aquests dipòsits electrònics cooperatius.

Relay-assisted transmission and radio resource management for wireless networks

The following paper presents an overview of the Ph.D Thesis1 presented in [1], which compiles all the research done during the period of time between 2004-2007. In that dissertation the relay-assisted transmission with half-duplex relays is analyzed from different points of view. This study is motivated by the necessity of finding innovative solutions to cope with the requirements of next generation wireless services, and with current radio technology. The use of relayed communications represents a change of paradigm of conventional communications, and requires the definition and evaluation of protocols to be applied to single or multiple-user relay communication. With the two fold goal of enhancing spectral efficiency and homogenize service in cellular communications, system design is investigated at physical (type of transmissions of the relay, decoding mode, ..) and upper layers (resource allocation, dynamic link control).

Label Space Reduction in All-Optical Label Switchiing Networks

Report for the scientific sojourn at the Department of Information Technology (INTEC) at the Ghent University, Belgium, from january to june 2007. All-Optical Label Swapping (AOLS) forms a key technology towards the implementation of All-Optical Packet Switching nodes (AOPS) for the future optical Internet. The capital expenditures of the deployment of AOLS increases with the size of the label spaces (i.e. the number of used labels), since a special optical device is needed for each recognized label on every node. Label space sizes are affected by the wayin which demands are routed. For instance, while shortest-path routing leads to the usage of fewer labels but high link utilization, minimum interference routing leads to the opposite. This project studies and proposes All-Optical Label Stacking (AOLStack), which is an extension of the AOLS architecture. AOLStack aims at reducing label spaces while easing the compromise with link utilization. In this project, an Integer Lineal Program is proposed with the objective of analyzing the softening of the aforementioned trade-off due to AOLStack. Furthermore, a heuristic aiming at finding good solutions in polynomial-time is proposed as well. Simulation results show that AOLStack either a) reduces the label spaces with a low increase in the link utilization or, similarly, b) uses better the residual bandwidth to decrease the number of labels even more.

OpenURL i l'enllaçat SFX

No fa gaires anys de les primeres recerques acadèmiques liderades per Herbert Van de Sompel a la Universitat de Gant a Bèlgica, les quals van donar com a resultat la formulació de l'estàndard OpenURL i el desenvolupament del servidor d'enllaços per a les biblioteques SFX, posant el control dels enllaços en mans del bibliotecari. Aquest article considera breument les primeres iniciatives sobre els enllaços, explica el propòsit i l'estructura d'OpenURL i el paper dels components: les fonts, els objectius i el servidor d'enllaços, centrant-se en el servidor d'enllaços SFX.

Harmonization guidelines for HLA-peptide multimer assays derived from results of a large scale international proficiency panel of the Cancer Vaccine Consortium.

PURPOSE: The Cancer Vaccine Consortium of the Cancer Research Institute (CVC-CRI) conducted a multicenter HLA-peptide multimer proficiency panel (MPP) with a group of 27 laboratories to assess the performance of the assay. EXPERIMENTAL DESIGN: Participants used commercially available HLA-peptide multimers and a well characterized common source of peripheral blood mononuclear cells (PBMC). The frequency of CD8+ T cells specific for two HLA-A2-restricted model antigens was measured by flow cytometry. The panel design allowed for participants to use their preferred staining reagents and locally established protocols for both cell labeling, data acquisition and analysis. RESULTS: We observed significant differences in both the performance characteristics of the assay and the reported frequencies of specific T cells across laboratories. These results emphasize the need to identify the critical variables important for the observed variability to allow for harmonization of the technique across institutions. CONCLUSIONS: Three key recommendations emerged that would likely reduce assay variability and thus move toward harmonizing of this assay. (1) Use of more than two colors for the staining (2) collect at least 100,000 CD8 T cells, and (3) use of a background control sample to appropriately set the analytical gates. We also provide more insight into the limitations of the assay and identified additional protocol steps that potentially impact the quality of data generated and therefore should serve as primary targets for systematic analysis in future panels. Finally, we propose initial guidelines for harmonizing assay performance which include the introduction of standard operating protocols to allow for adequate training of technical staff and auditing of test analysis procedures.

Nasal immunization of mice with human papillomavirus type 16 virus-like particles elicits neutralizing antibodies in mucosal secretions.

To specifically induce a mucosal antibody response to purified human papillomavirus type 16 (HPV16) virus-like particles (VLP), we immunized female BALB/c mice orally, intranasally, and/or parenterally and evaluated cholera toxin (CT) as a mucosal adjuvant. Anti-HPV16 VLP immunoglobulin G (IgG) and IgA titers in serum, saliva, and genital secretions were measured by enzyme-linked immunosorbent assay (ELISA). Systemic immunizations alone induced HPV16 VLP-specific IgG in serum and, to a lesser extent, in genital secretions but no secretory IgA. Oral immunization, even in the presence of CT, was inefficient. However, three nasal immunizations with 5 microgram of VLP given at weekly intervals to anesthetized mice induced high (>10(4)) and long-lasting (>15 weeks) titers of anti-HPV16 VLP antibodies in all samples, including IgA and IgG in saliva and genital secretions. CT enhanced the VLP-specific antibody response 10-fold in serum and to a lesser extent in saliva and genital secretions. Nasal immunization of conscious mice compared to anesthetized mice was inefficient and correlated with the absence of uptake of a marker into the lung. However, a 1-microgram VLP systemic priming followed by two 5-microgram VLP intranasal boosts in conscious mice induced both HPV16 VLP-specific IgG and IgA in secretions, although the titers were lower than in anesthetized mice given three intranasal immunizations. Antibodies in serum, saliva, and genital secretions of immunized mice were strongly neutralizing in vitro (50% neutralization with ELISA titers of 65 to 125). The mucosal and systemic/mucosal HPV16 VLP immunization protocols that induced significant titers of neutralizing IgG and secretory IgA in mucosal secretions in mice may be relevant to genital HPV VLP-based human vaccine trials.