4,335 research outputs found
Development of low-pH cementitious materials for HLRW repositories. Resistance against ground waters aggression
One of the most accepted engineering construction concepts of underground repositories for high radioactive waste considers the use of low-pH cementitious materials. This paper deals with the design of those based on Ordinary Portland Cements with high contents of silica fume and/or fly ashes that modify most of the concrete “standard” properties, the pore fluid composition and the microstructure of the hydrated products. Their resistance to long-term groundwater aggression is also evaluated. The results show that the use of OPC cement binders with high silica content produces low-pH pore waters and the microstructure of these cement pastes is different from the conventional OPC ones, generating C–S–H gels with lower CaO/SiO2 ratios that possibly bind alkali ions. Leaching tests show a good resistance of low-pH concretes against groundwater aggression although an altered front can be observe
Assessing Creativity In Engineering Students: A Comparative Between Degrees and Sudents In First And Last Year
An online open access test (CREAX self-assessment) has been used in this work so that students from degrees in engineering in the Universidad Polite¿cnica of Madrid (UPM) could self-assess their creative competence after several classroom activities. Different groups from the first year course have been statistically compared using data from their assessment. These first year students had different professors in the subject ?Technical Drawing? and belonged to several degrees in the UPM. They were as well compared regarding sex and a group of first year students was also compared to another last year group of the degree so as to observe possible differences in the achievement of this competence. Only one difference was detected concerning sex in one of the degrees. Among degrees, the higher marks obtained by students who had done specific exercises for the development of creativity in class is highlighted. Finally, a significantly high mark was observed in students during their last year of degree with respect to first year students. The tool CREAX has become very useful in the assessment of this competence in the UPM degrees in which it has been implemented
Bacterial outer membrane vesicles and vaccine applications
Vaccines based on outer membrane vesicles (OMV) were developed more than 20 years ago against Neisseria meningitidis serogroup B. These nano-sized structures exhibit remarkable potential for immunomodulation of immune responses and delivery of “self” meningococcal antigens or unrelated antigens incorporated into the vesicle structure. This paper reviews different applications in OMV Research and Development (R&D) and provides examples of OMV developed and evaluated at the Finlay Institute in Cuba. A Good Manufacturing Practice (GMP) process was developed at the Finlay Institute to produce OMV from N. meningitidis serogroup B (dOMVB) using detergent extraction. Subsequently, OMV from N. meningitidis, serogroup A (dOMVA), serogroup W (dOMVW) and serogroup X (dOMVX) were obtained using this process. More recently, the extraction process has also been applied effectively for obtaining OMV on a research scale from Vibrio cholerae (dOMVC), Bordetella pertussis (dOMVBP), Mycobacterium smegmatis (dOMVSM) and BCG (dOMVBCG). The immunogenicity of the OMV have been evaluated for specific antibody induction, and together with functional bactericidal and challenge assays in mice have shown their protective potential. dOMVB has been evaluated with non-self neisserial antigens, including with a herpes virus type 2 glycoprotein, ovalbumin and allergens. In conclusion, OMV are proving to be more versatile than first conceived and remain an important technology for development of vaccine candidates. - See more at: http://journal.frontiersin.org/Journal/10.3389/fimmu.2014.00121/abstract#sthash.MwqUyZQ1.dpu
Caracterización de residuos procedentes de los procesos de combustión de biomasa. Viabilidad de uso como materiales de Construcción.
En España, y más específicamente en Andalucía, la producción de energía a partir de la quema de biomasa presenta una actividad creciente, por lo que la caracterización de los residuos procedentes de esta combustión facilitaría su empleo futuro. En el presente trabajo se estudia la viabilidad técnica que presentan ciertos residuos (cenizas volantes y cenizas de fondo) procedentes de dicha combustión, para ser empleados en materiales de construcción, evaluando la composición química y mineralógica de estos residuos. Los resultados obtenidos muestran que los residuos analizados poseen propiedades aceptables para ser utilizados en la producción de materiales que tomen como base el cemento, si bien su calidad y tipo de aplicación depende de la procedencia del residu
Osteoarthritis:Mechanistic Insights, Senescence, and Novel Therapeutic Opportunities
Osteoarthritis (OA) is the most common joint disease. In the last years, the research community has focused on understanding the molecular mechanisms that led to the pathogenesis of the disease, trying to identify different molecular and clinical phenotypes along with the discovery of new therapeutic opportunities. Different types of cell-to-cell communication mechanisms have been proposed to contribute to OA progression, including mechanisms mediated by connexin43 (Cx43) channels or by small extracellular vesicles. Furthermore, changes in the chondrocyte phenotype such as cellular senescence have been proposed as new contributors of the OA progression, changing the paradigm of the disease. The use of different drugs able to restore chondrocyte phenotype, to reduce cellular senescence and senescence-associated secretory phenotype components, and to modulate ion channel activity or Cx43 appears to be promising therapeutic strategies for the different types of OA. In this review, we aim to summarize the current knowledge in OA phenotypes related with aging and tissue damage and the new therapeutic opportunities currently available
Gene Editing in Adult Hematopoietic Stem Cells
Over the last years, an important development has allowed the scientific community to address a precise and accurate modification of the genome. The first probe of concept appeared with the design and use of engineered zinc-finger nucleases (ZFNs), which was expanded later on with the discovery and engineering of meganucleases and transcription activator-like effector nucleases (TALENs) and finally democratized and made easily available to the whole scientific community with the discovery of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 nuclease combination technology. The availability of these tools has allowed a precise gene editing, such as knockout of a specific gene or the correction of a defective gene by means of homologous recombination (HR), taking advantage of the endogenous cell repair machinery. This process was already known and used but was inefficient—efficiency that has been increased more than 100-fold with the addition of the mentioned specific nucleases to the process. Apart from the proper design of the nucleases to recognize and cut the selected site in the cell genome, two main goals need to be adequately addressed to optimize its function: the delivery of the tools into the desired cells and the selection of those where the gene editing process has occurred correctly. Both steps can be easily solved when the source of cells is extensive or can be expanded and manipulated in vitro extensively, such as immortalized cell lines or pluripotent stem cells (embryonic stem cells and induced pluripotent stem cells). However, both steps are critical in the case of primary cells, such as the hematopoietic stem cells (HSCs). HSCs are a rare cell population present in the bone marrow (BM) of higher mammals, and it is the responsible for the maintenance and replenishment of all hematopoietic cells for the lifespan of the animals by means of two fundamental properties: self-renewal and multipotency. HSC population is then the ideal target for the correction of hematopoietic genetic diseases and also for the knockout of the responsible genes to in vitro and in vivo model those hematopoietic diseases. This rare population cannot be expanded and its in vitro manipulation and culture negatively affects their fundamental properties of self-renewal and multipotency. These factors challenge the application of gene editing to HSCs. Important efforts are now ongoing trying to optimize the protocols of gene delivery and selection for HSCs. This chapter will review and discuss how researchers are trying to solve them, all attempts that are ongoing and the potential application of the technology to the patients affected with hematopoietic genetic diseases
Multitasking Compensatory Saccadic Training Program for Hemianopia Patients: A New Approach With 3-Dimensional Real-World Objects
Producción CientíficaPurpose: To examinewhether a noncomputerized multitasking compensatory saccadic
training program (MCSTP) for patients with hemianopia, based on a reading
regimen and eight exercises that recreate everyday visuomotor activities using threedimensional
(3D) real-world objects, improves the visual ability/function, quality of life
(QL), and functional independence (FI).
Methods: The 3D-MCSTP included four in-office visits and two customized homebased
daily training sessions over 12weeks. A quasiexperimental, pretest/posttest study
designwas carried out with an intervention group (IG) (n = 20) and a no-training group
(NTG) (n = 20) matched for age, hemianopia type, and brain injury duration.
Results: The groups were comparable for the main baseline variables and all participants
(n = 40) completed the study. The IGmainly showed significant improvements in
visual-processing speed (57.34% ± 19.28%; P < 0.0001) and visual attention/retention
ability (26.67% ± 19.21%; P < 0.0001), which also were significantly greater (P < 0.05)
than in the NTG. Moreover, the IG showed large effect sizes (Cohen’s d) in 75% of the
totalQL and FI dimensions analyzed; in contrast to the NTGthat showed negligiblemean
effect sizes in 96% of these dimensions.
Conclusions: The customized 3D-MCSTP was associated with a satisfactory response in
the IG for improving complex visual processing, QL, and FI.
Translational Relevance: Neurovisual rehabilitation of patientswith hemianopia seems
more efficient when programs combine in-office visits and customized home-based
training sessions based on real objects and simulating real-life conditions, than no treatment
or previously reported computer-screen approaches, probably because of better
stimulation of patients´ motivation and visual-processing speed brain mechanisms
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