Nanomotors: new strategies of (bio)sensing based on motion

Nanomotors are nanoscale devices capable of converting energy into movement and forces. Among them, self-propelled nanomotors offer considerable promise for developing new and novel bioanalytical and biosensing strategies based on the direct isolation of target biomolecules or changes in their movement in the presence of target analytes. The mainachievements of this project consists on the development of receptor-functionalized nanomotors that offer direct and rapid target detection, isolation and transport from raw biological samples without preparatory and washing steps. For example, microtube engines functionalized with aptamer, antibody, lectin and enzymes receptors were used for the direct isolation of analytes of biomedical interest, including proteins and whole cells, among others. A target protein was also isolated from a complex sample by using an antigen-functionalized microengine navigating into the reservoirs of a lab-on-a-chip device. The new nanomotorbased target biomarkers detection strategy not only offers highly sensitive, rapid, simple and low cost alternative for the isolation and transport of target molecules, but also represents a new dimension of analytical information based on motion. The recognition events can be easily visualized by optical microscope (without any sophisticated analytical instrument) to reveal the target presence and concentration. The use of artificial nanomachines has shown not only to be useful for (bio)recognition and (bio)transport but also for detection of environmental contamination and remediation. In this context, micromotors modified with superhydrophobic layer demonstrated that effectively interacted, captured, transported and removed oil droplets from oil contaminated samples. Finally, a unique micromotor-based strategy for water-quality testing, that mimics live-fish water-quality testing, based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants was also developed. The attractive features of the new micromachine-based target isolation and signal transduction protocols developed in this project offer numerous potential applications in biomedical diagnostics, environmental monitoring, and forensic analysis.

Pol��tiques, pr��ctiques i estrat��gies d'inserci��: una mirada des de les traject��ries de les dones immigrades

Aquesta recerca, amb l���objectiu general de con��ixer i analitzar els processos d���inserci�� al mercat laboral, les estrat��gies i pr��ctiques d���inserci��, i els ��mbits d���ocupaci�� de les dones immigrades en la societat de recepci��, es va plantejar com a finalitat proposar l��nies d'actuaci�� i pr��ctiques d'atenci�� vers aquest col���lectiu. Sota l���eix 1 del Pacte Nacional, apunta a garantir la igualtat de drets i l���acc��s al mercat laboral de les persones, des de la tranversalitat del g��nere. Mitjan��ant l���aplicaci�� d'entrevistes semiestructurades per tal de construir "traject��ries d���immigraci��" de dones, i obtenir una mirada sociohist��rica i din��mica del proc��s de d���inserci�� laboral a la societat de recepci��, es va portar a terme la recerca amb la participaci�� de 17 dones immigrades al territori catal��. Entre els resultats, cal destacar que: en quant als relats d���origen destaca la diversitat de motius de la immigraci��, posant en q��esti�� les tesis purament economicistes, i en relaci�� amb les pol��tiques i pr��ctiques d���inserci�� laboral, podem confirmar que els esfor��os dels recursos d���atenci�� tendeixen a encertar a les dones en els n��nxols laborals m��s precaritzats, i sobre tot generitzats. Per altre banda, l���estudi ens ha permet apropar-nos a les estrat��gies que fan servir les dones per a sortejar les limitacions, sobre tot legals, que es troben a la societat de recepci��. Aquestes accions ens permeten analitzar l���ag��ncia de les dones immigrades i la import��ncia de les xarxes socials i de la participaci��, per a una inserci�� sociolaboral m��s plena. A m��s de les conclusions i recomanacions contingudes en aquest document, s'ha elaborat un material did��ctic que es composa de: 1. Documental "Per compte ali��" en el qual hi ha les hist��ries d'inserci�� de 5 dones i; 2. Guia de 12 tallers de treball com a proposta d���intervenci��, destinats als col���lectius i serveis que treballen per a la inserci��.

Integration of olfactory information in a spatial representation enabling accurate arm choice in the radial arm maze

The aim of the present study was to determine whether and how rats can use local olfactory cues for spatial orientation. Rats were trained in an eight-arm radial maze under different conditions as defined by the presence or absence of supplementary olfactory cues marking each arm, the availability of distant visuospatial information, and the illumination of the maze (light or darkness). The different visual conditions were designed to dissociate among the effects of light per se and those of visuospatial cues, on the use of olfactory cues for accurate arm choice. Different procedures with modifications of the arrangement of olfactory cues were used to determine if rats formed a representation of the spatial configuration of the olfactory cues and if they could rely on such a representation for accurate arm choice in the radial maze. The present study demonstrated that the use of olfactory cues to direct arm choice in the radial arm maze was critically dependent on the illumination conditions and implied two different modes of processing of olfactory information according to the presence or the absence of light. Olfactory cues were used in an explicit manner and enabled accurate arm choice only in the absence of light. Rats, however, had an implicit memory of the location of the olfactory cues and formed a representation of the spatial position of these cues, whatever the lighting conditions. They did not memorize the spatial configuration of the olfactory cues per se but needed these cues to be linked to the external spatial frame of reference.

Anti-tumour effect of monoclonal antibodies against selected antigens expressed by B-cells in Chronic Lymphocytic Leukaemia : strategies to enhance the efficacy of immunotherapy

R��sum�� : Les anticorps monoclonaux ont une place de plus en plus pr��pond��rante dans le traitement des lymphomes et leuc��mies. Dans cette ��tude, trois anticorps monoclonaux murins, dirig��s contre les antig��nes CDS, CD71 et HLA-DR exprim��s �� la surface des cellules de leuc��mies lympho��des chroniques (LLC), ont ��t�� ��valu��s. In vitro, les anticorps radiomarqu��s ont montr��s des bonnes liaisons sp��cifiques sur les diff��rentes cellules cibles. L'anti-CD71 inhibait la prolif��ration de la plupart des lign��es cellulaires test��es avec une accumulation des cellules en phase S pr��coce du cycle cellulaire. L'anti-HLA-DR inhibait aussi la prolif��ration des lign��es leuc��mique JOK1-5.3 et lympho��de Daudi. Cette inhibition ��tait associ��e �� une agr��gation des cellules. Aucune induction d'apoptose n'a pu ��tre clairement observ��e avec ces anticorps. L'anti-CD5 n'a montr�� aucun effet d'inhibition de croissance in vitro. In vivo, l'injection des anticorps individuellement augmentait significativement la survie m��diane de souris SCID greff��es avec des cellules JOK1-5.3 en i.p. De plus, l'anticorps antiCD5 combin�� �� l'anti-HLA-DR ou l'anti-CD71, sous certaines conditions, inhibait compl��tement le d��veloppement tumoral dans la quasi totalit�� des souris trait��es avec une augmentation significative de l'efficacit�� compar��e aux anticorps seuls. L'augmentation de l'efficacit�� th��rapeutique des anticorps monoclonaux par les cytokines, dont l'IL-2, a d��j�� ��t�� montr��e dans la litt��rature. Au regard du meilleur comportement de l'IL-2 sous la forme complex��e �� un anticorps anti-IL-2, nous avons ��valu�� l'efficacit�� de l'IL-2/anti-IL-2 seul ou combin��s au rituximab chez diff��rents mod��les tumoraux s.c. (BL60.2, Daudi, Ramos) ou i.p. (JOK15.3) de souris SCID. Le complexe IL-2/anti-IL-2 a montr�� un effet anti-tumoral dans les souris greff��es avec BL60.2 et Daudi. Le traitement IL-2/anti-IL-2 combin�� au rituximab a montr�� une efficacit�� accrue chez des souris avec BL60.2 par rapport au rituximab seul. En revanche, nous n'avons pas observ�� de diff��rence avec IL-2/anti-IL-2 seul.Aussi, nous avons ��valu�� l'utilisation de l'agent couplant tri-fonctionnel TMEA pour produire des anticorps bispecifiques. Les exp��riences pr��liminaires avec les anticorps rituximab et herceptine, ont mis en ��vidence sur gel SDS-Page la formation de dimers (~100kDa) et de trimers (~150kDa). Les anticorps bispecifiques sont compos��s d'un fragment Fab' d'une sp��cificit�� et de un ou deux fragments Fab' de l'autre sp��cificit�� permettant de moduler la capacit�� de liaison. Nous avons enfin montr�� qu'une construction anti-CD5/anti-CD20 ��tait capable de se lier ind��pendamment ou simultan��ment �� ses antig��nes cibles. En conclusion, ce travail a montr�� l'efficacit�� th��rapeutique des trois anticorps monoclonaux ��tudi��s dans un model de LLC in vivo, et plus particuli��rement l'int��r��t de certaines combinaisons. D'autre part, nous avons montr�� l'efficacit�� anti-tumorale du complexe IL-2/anti-IL-2 in vivo. Des ��tudes futures devront permettre de d��finir un r��gime favorable pour augmenter l'efficacit�� de la th��rapie avec les anticorps monoclonaux. Enfin, nous avons montr�� la faisabilit�� d'utiliser l'agent couplant TMEA pour produire des anticorps bisp��cifiques fonctionnels.Abstract : Monoclonal antibody (mAb) therapy has become an integral part in different treatments of lymphomas and leukaemias. In this study, we describe three murine mAbs directed against the CD5, CD71 and HLA-DR antigens expressed on chronic lymphocytic leukaemia cells (CLL). In vitro, radiolabeled purified mAbs showed good specific binding on live target cells. Anti-CD71 mAb inhibited proliferation of most cell lines with an accumulation of responding cells in early S-phase of the cell cycle, but without induction of apoptosis. Anti-HLA-DR mAb showed proliferation inhibition of leukaemia JOK1-5.3 and lymphoid Daudi cells, associated with cell aggregation, but again no specific sign of apoptosis was observed. Anti-CD5 mAb did not show any growth inhibitory effect in vitro. In vivo, in a model of SCID mice grafted i.p. with JOK1-5.3 cells, injection of individual mAbs induced significant prolongation of median survival, up to complete inhibition of tumour growth in some mice. Antibody combination of anti-CD5 with anti-HLA-DR or anti-CD71, evaluated in an early treatment, completely inhibited tumour growth in most mice, with a significant efficacy enhancement as compared to mAb used as single agents. Previous reports described the improved efficacy of mAb therapy when combined with cytokines such as IL-2. Relying further on the improved efficacy of IL-2 when administered as an immune complex with anti-IL-2 mAb, we evaluated the anti-tumour effect of the IL-2/anti-IL-2 complex alone or combined with rituximab in subcutaneous (BL60.2, Daudi, Ramos) or i.p. (JOK1-5.3) tumour models in SCID mice. The IL-2/anti-IL-2 complex demonstrated an anti-tumour effect in BL60.2 and Daudi grafted SCID mice. Combination of IL-2/anti-IL-2 treatment with rituximab showed increased efficacy as compared to rituximab alone in BL60.2 grafted mice. However, no difference was observed with IL-2/anti-IL-2 complex alone in these experiments. Finally, we evaluated the feasibility of producing bispecific antibodies (bsAbs) using a trifunctional coupling agent, called TMEA. In preliminary experiments coupling rituximab with herceptine Fab' fragments we obtained the formation of dimers (~100kDa) and trimers (~150kDa) as observed on SDS-Page gel. This method allowed us to produce bsAb with one Fab' fragments of one specificity and one or two Fab' fragments of the second specificity. An anti-CD5/anti-CD20 bsAb was shown to bind targeted antigen either independently or simultaneously. In conclusion, these data show that the three mAbs were all able to induce significant growth inhibition of the JOK1-5.3 cell line in vivo, and efficacy was enhanced when used in combination. IL2/anti-IL-2 complex displayed anti-tumour efficacy in vivo. Further evaluation is necessary to define the most favourable combination to improve mAb therapy. BsAb were produced using the tri-functional agent allowing antibody fragments with relatively good binding. The poor yield obtained with such chemical couplings limited the use of these constructs in preclinical experiments.

From SNPs to pathways: integration of functional effect of sequence variations on models of cell signalling pathways

Background: Single nucleotide polymorphisms (SNPs) are the most frequent type of sequence variation between individuals, and represent a promising tool for finding genetic determinants of complex diseases and understanding the differences in drug response. In this regard, it is of particular interest to study the effect of non-synonymous SNPs in the context of biological networks such as cell signalling pathways. UniProt provides curated information about the functional and phenotypic effects of sequence variation, including SNPs, as well as on mutations of protein sequences. However, no strategy has been developed to integrate this information with biological networks, with the ultimate goal of studying the impact of the functional effect of SNPs in the structure and dynamics of biological networks. Results: First, we identified the different challenges posed by the integration of the phenotypic effect of sequence variants and mutations with biological networks. Second, we developed a strategy for the combination of data extracted from public resources, such as UniProt, NCBI dbSNP, Reactome and BioModels. We generated attribute files containing phenotypic and genotypic annotations to the nodes of biological networks, which can be imported into network visualization tools such as Cytoscape. These resources allow the mapping and visualization of mutations and natural variations of human proteins and their phenotypic effect on biological networks (e.g. signalling pathways, protein-protein interaction networks, dynamic models). Finally, an example on the use of the sequence variation data in the dynamics of a network model is presented. Conclusion: In this paper we present a general strategy for the integration of pathway and sequence variation data for visualization, analysis and modelling purposes, including the study of the functional impact of protein sequence variations on the dynamics of signalling pathways. This is of particular interest when the SNP or mutation is known to be associated to disease. We expect that this approach will help in the study of the functional impact of disease-associated SNPs on the behaviour of cell signalling pathways, which ultimately will lead to a better understanding of the mechanisms underlying complex diseases.

Free-and open source software for a course on network management: authoring and enactment of scripts based on collaborative learning strategies

This paper describes a Computer-Supported Collaborative Learning (CSCL) case study in engineering education carried out within the context of a network management course. The case study shows that the use of two computing tools developed by the authors and based on Free- and Open-Source Software (FOSS) provide significant educational benefits over traditional engineering pedagogical approaches in terms of both concepts and engineering competencies acquisition. First, the Collage authoring tool guides and supports the course teacher in the process of authoring computer-interpretable representations (using the IMS Learning Design standard notation) of effective collaborative pedagogical designs. Besides, the Gridcole system supports the enactment of that design by guiding the students throughout the prescribed sequence of learning activities. The paper introduces the goals and context of the case study, elaborates onhow Collage and Gridcole were employed, describes the applied evaluation methodology, anddiscusses the most significant findings derived from the case study.

@neurIST infrastructure for advanced disease management through integration of heterogeneous data, computing, and complex processing services

The increasing volume of data describing humandisease processes and the growing complexity of understanding, managing, and sharing such data presents a huge challenge for clinicians and medical researchers. This paper presents the@neurIST system, which provides an infrastructure for biomedical research while aiding clinical care, by bringing together heterogeneous data and complex processing and computing services. Although @neurIST targets the investigation and treatment of cerebral aneurysms, the system���s architecture is generic enough that it could be adapted to the treatment of other diseases.Innovations in @neurIST include confining the patient data pertaining to aneurysms inside a single environment that offers cliniciansthe tools to analyze and interpret patient data and make use of knowledge-based guidance in planning their treatment. Medicalresearchers gain access to a critical mass of aneurysm related data due to the system���s ability to federate distributed informationsources. A semantically mediated grid infrastructure ensures that both clinicians and researchers are able to seamlessly access andwork on data that is distributed across multiple sites in a secure way in addition to providing computing resources on demand forperforming computationally intensive simulations for treatment planning and research.

Learning design twofold strategies for teacher-led inquiry andstudent active learning

This workshop paper states that fostering active student participation both in face-to-face lectures / seminars and outside the classroom (personal and group study at home, the library, etc.) requires a certain level of teacher-led inquiry. The paper presents a set of strategies drawn from real practice in higher education with teacher-led inquiry ingredients that promote active learning. Thesepractices highlight the role of the syllabus, the importance of iterative learning designs, explicit teacher-led inquiry, and the implications of the context, sustainability and practitioners��� creativity. The strategies discussed in this paper can serve as input to the workshop as real cases that need to be represented in design and supported in enactment (with and without technologies).

Vertical Product Differentiation, Entry-Deterrence Strategies, and Entry Qualities, September 2005

We analyze the entry of a new product into a vertically differentiated market in which an entrant and an incumbent compete in prices. Here the entry-deterrence strategies of the incumbent firm rely on ���limit qualities.��� With a sequential choice of quality, a quality-dependent marginal production cost, and a fixed entry cost, we relate the entry-quality decision and the entry-deterrence strategies to the level of entry cost and the degree of consumer heterogeneity. Quality-dependent marginal production costs in the model entail the possibility of inferior-quality entry as well as an incumbent���s aggressive entry-deterrence strategies of increasing its quality level toward potential entry. Welfare evaluation confirms that social welfare is not necessarily improved when entry is encouraged rather than deterred.

Current drug discovery strategies against arenavirus infections.

Arenaviruses are a large group of emerging viruses including several causative agents of severe hemorrhagic fevers with high mortality in man. Considering the number of people affected and the currently limited therapeutic options, novel efficacious therapeutics against arenaviruses are urgently needed. Over the past decade, significant advances in knowledge about the basic virology of arenaviruses have been accompanied by the development of novel therapeutics targeting different steps of the arenaviral life cycle. High-throughput, small-molecule screens identified potent and broadly active inhibitors of arenavirus entry that were instrumental for the dissection of unique features of arenavirus fusion. Novel inhibitors of arenavirus replication have been successfully tested in animal models and hold promise for application in humans. Late in the arenavirus life cycle, the proteolytic processing of the arenavirus envelope glycoprotein precursor and cellular factors critically involved virion assembly and budding provide further promising 'druggable' targets for novel therapeutics to combat human arenavirus infection.

Cross National Contact Strategies

Using paradata gathered from the 11-nation Survey of Health, Ageing and Retirement in Europe (SHARE), this paper examines the impact of the first contact attempt and the first contact properties, respectively, on contact and response efficiency using logistic multilevel models. We find that despite the different sample frames and interviewer compensation structure between countries, there are no considerable country effects with respect to making contact, once interviewer effects are controlled. Moreover, results point to an increased efficiency associated with evenings especially on Sundays, at least on the very first contact attempt. For attempts that result in initial contact, Saturday afternoons are most likely to eventually lead to completed interviews, followed by initial contact on weekdays during the daytime. We hypothesize that this may be due to the SHARE sample being composed of people aged 50 and over.

Vaccination Strategies against Highly Pathogenic Arenaviruses: The Next Steps toward Clinical Trials.

Vaccination is one of the most valuable weapons against infectious diseases and has led to a significant reduction in mortality and morbidity. However, for most viral hemorrhagic fevers caused by arenaviruses, no prophylactic vaccine is available. This is particularly problematic as these diseases are notoriously difficult to diagnose and treat. Lassa fever is globally the most important of the fevers caused by arenaviruses, potentially affecting millions of people living in endemic areas, particularly in Nigeria. Annually, an estimated 300,000 humans are infected and several thousands succumb to the disease. The successful development of the vaccine "Candid#1" against Junin virus, the causative agent of Argentine hemorrhagic fever, proved that an effective arenavirus vaccine can be developed. Although several promising studies toward the development of a Lassa fever vaccine have been published, no vaccine candidate has been tested in human volunteers or patients. This review summarizes the immunology and other aspects of existing experimental arenavirus vaccine studies, discusses the reasons for the lack of a vaccine, and proposes a plan for overcoming the final hurdles toward clinical trials.