87 research outputs found

    Impact of antigen density on recognition by monoclonal antibodies

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    Understanding antigen-antibody interactions is important to many emerging medical and bioanalytical applications. In particular, the levels of antigen expression at the cell surface may determine antibody-mediated cell death. This parameter has a clear effect on outcome in patients undergoing immunotherapy. In this context, CD20 which is expressed in the membrane of B cells has received significant attention as target for immunotherapy of leukemia and lymphoma using the monoclonal antibody rituximab. To systematically study the impact of CD20 density on antibody recognition, we designed self-assembled monolayers that display tunable CD20 epitope densities. For this purpose, we developed in situ click chemistry to functionalize SPR sensor chips. We find that the rituximab binding affinity depends sensitively and non-monotoneously on CD20 surface density. Strongest binding, with an equilibrium dissociation constant (KD = 32 nM) close to values previously reported from in vitro analysis with B cells (apparent KD between 5 and 19 nM), was obtained for an average inter-antigen spacing of 2 nm. This distance is required for improving rituximab recognition, and in agreement with the known requirement of CD20 to form clusters to elicit a biological response. More generally, this study offers an interesting outlook in the understanding of the necessity of epitope clusters for effective mAb recognition

    Comparison of SMOS and SMAP Soil Moisture Retrieval Approaches Using Tower-based Radiometer Data over a Vineyard Field

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    The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (TB) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular TB data at horizontal and vertical polarization for a range of incidence angles (30-60). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and Mattar) were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the reference SM data set derived from the multi-angular observations (R2 around 0.90, RMSE varying between 0.035 and 0.056 m3m3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the Saleh methods based on either bi-angular or bipolarization observations (R2 around 0.93, RMSE around 0.035 m3m3). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R2 around 0.75, RMSE around 0.055 m3m3). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals

    Description of the Vitis vinifera L. phenotypic variability in eno-carpological traits by a Euro-Asiatic collaborative network among ampelographic collections

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    The grapevine intra-specific variability captured an increasing interest during the last decades, as demonstrated by the number of recently funded European projects focused on the grapevine biodiversity preservation. However, nowadays, crop plants are mainly characterized by genotyping methods. The present work summarizes the phenotype data collected among 20 ampelographic collections spread in 15 countries, covering mostly of the viticultural areas in the Euro-Asiatic range: from Portugal to Armenia and from Cyprus to Luxembourg. Together with agro-climatic characterization of the experimental site, in two years, about 2400 accessions were described, following a common experimental protocol mainly focused on the carpological and oenological traits, obtaining a general overview of the distribution of the considered phenotypic traits in the cultivated Vitis vinifera species. The most replicated cultivars were selected and, for the subset of these reference cultivars, their behavior in the different environmental conditions over sites and years was described by ANOVA methods

    Description of the vitis vinifera L. Phenotypic variability in eno-carpological traits by a Euro-Asiatic collaborative network among ampelographic collections

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    The grapevine intra-specific variability captured an increasing interest during the last decades, as demonstrated by the number of recently funded European projects focused on the grapevine biodiversity preservation. However, nowadays, crop plants are mainly characterized by genotyping methods. The present work summarizes the phenotype data collected among 20 ampelographic collections spread over 15 countries, covering most of the viticultural areas in the Euro-Asiatic region: from Portugal to Armenia and from Cyprus to Luxembourg. Together with agro-climatic characterization of the experimental site, over two years about 2,400 accessions were described. A common experimental protocol mainly focused on the carpological and oe-nological traits was followed, obtaining a general overview of the distribution of the considered phenotypic traits in the cultivated Vitis vinifera species. The most replicated cultivars were selected and, for the subset of these reference cultivars, their behavior in the different environmental conditions over sites and years was described by ANOVA methods

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Control of adhesion using surface functionalisations for robotic microhandling

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