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Search Results: 1 - 10 of 2751 matches for " Luigi Guarino "
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Biomimetic Strategies for Bone Repair and Regeneration
Maria G. Raucci,Vincenzo Guarino,Luigi Ambrosio
Journal of Functional Biomaterials , 2012, DOI: 10.3390/jfb3030688
Abstract: The osseointegration rate of implants is related to their composition and surface roughness. Implant roughness favors both bone anchoring and biomechanical stability. Osteoconductive calcium phosphate (Ca-P) coatings promote bone healing and apposition, leading to the rapid biological fixation of implants. It has been clearly shown in many publications that Ca-P coating accelerates bone formation around the implant. This review discusses two main routes for the manufacturing of polymer-based osteoconductive scaffolds for tissue engineering, namely the incorporation of bioceramic particles in the scaffold and the coating of a scaffold with a thin layer of apatite through a biomimetic process.
Global Ex-Situ Crop Diversity Conservation and the Svalbard Global Seed Vault: Assessing the Current Status
Ola T. Westengen, Simon Jeppson, Luigi Guarino
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064146
Abstract: Ex-situ conservation of crop diversity is a global concern, and the development of an efficient and sustainable conservation system is a historic priority recognized in international law and policy. We assess the completeness of the safety duplication collection in the Svalbard Global Seed Vault with respect to data on the world's ex-situ collections as reported by the Food and Agriculture Organization of the United Nations. Currently, 774,601 samples are deposited at Svalbard by 53 genebanks. We estimate that more than one third of the globally distinct accessions of 156 crop genera stored in genebanks as orthodox seeds are conserved in the Seed Vault. The numbers of safety duplicates of Triticum (wheat), Sorghum (sorghum), Pennisetum (pearl millet), Eleusine (finger millet), Cicer (chickpea) and Lens (lentil) exceed 50% of the estimated numbers of distinct accessions in global ex-situ collections. The number of accessions conserved globally generally reflects importance for food production, but there are significant gaps in the safety collection at Svalbard in some genera of high importance for food security in tropical countries, such as Amaranthus (amaranth), Chenopodium (quinoa), Eragrostis (teff) and Abelmoschus (okra). In the 29 food-crop genera with the largest number of accessions stored globally, an average of 5.5 out of the ten largest collections is already represented in the Seed Vault collection or is covered by existing deposit agreements. The high coverage of ITPGRFA Annex 1 crops and of those crops for which there is a CGIAR mandate in the current Seed Vault collection indicates that existence of international policies and institutions are important determinants for accessions to be safety duplicated at Svalbard. As a back-up site for the global conservation system, the Seed Vault plays not only a practical but also a symbolic role for enhanced integration and cooperation for conservation of crop diversity.
Hydrogel-Based Platforms for the Regeneration of Osteochondral Tissue and Intervertebral Disc
Vincenzo Guarino,Antonio Gloria,Maria Grazia Raucci,Luigi Ambrosio
Polymers , 2012, DOI: 10.3390/polym4031590
Abstract: Hydrogels currently represent a powerful solution to promote the regeneration of soft and hard tissues. Primarily, they assure efficient bio-molecular interactions with cells, also regulating their basic functions, guiding the spatially and temporally complex multi-cellular processes of tissue formation, and ultimately facilitating the restoration of structure and function of damaged or dysfunctional tissues. In order to overcome basic drawbacks of traditional synthesized hydrogels, many recent strategies have been implemented to realize multi-component hydrogels based on natural and/or synthetic materials with tailored chemistries and different degradation kinetics. Here, a critical review of main strategies has been proposed based on the use of hydrogels-based devices for the regeneration of complex tissues, i.e ., osteo-chondral tissues and intervertebral disc.
The impact of local extinction on genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica: consequences for the conservation of plant genetic resources
Daniel Barrantes,Gabriel Macaya,Luigi Guarino,Jean Pierre Baudoin
Revista de Biología Tropical , 2008,
Abstract: Plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. Species may also colonize the same site on multiple occasions. Here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central valley of Costa Rica. We compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. Locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). Our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. However, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. Recolonized locations showed the highest level of genetic differentiation (mean Fst= 0.2769), followed by control locations (mean Fst= 0.0576) and experimental locations (mean Fst= 0.0189). Similar findings were observed for Nei’s genetic distance between samples (di,j= 0.1786, 0.0400, and 0.0037, respectively). Our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. These findings also showed that control populations are not in equilibrium. Implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. Rev. Biol. Trop. 56 (3): 1023-1041. Epub 2008 September 30. Las poblaciones de plantas pueden experimentar extinción local, y al mismo tiempo, pueden surgir a sus alrededores nuevas poblaciones. Algunas especies pueden colonizar el mismo sitio en múltiples ocasiones. Aquí examinamos el impacto de la extinción local y recolonización en la estructura genética de poblaciones silvestres del frijol lima (Phaseolus lunatus) en el valle Central de Costa Rica. Comparamos la diversidad genética de muestras tomadas en poblaciones, antes y después de la extinción, en 13 sitios, usando marcadores de microsatélite. Según los episodios de exti
A Gap Analysis Methodology for Collecting Crop Genepools: A Case Study with Phaseolus Beans
Julián Ramírez-Villegas,Colin Khoury,Andy Jarvis,Daniel Gabriel Debouck,Luigi Guarino
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013497
Abstract: The wild relatives of crops represent a major source of valuable traits for crop improvement. These resources are threatened by habitat destruction, land use changes, and other factors, requiring their urgent collection and long-term availability for research and breeding from ex situ collections. We propose a method to identify gaps in ex situ collections (i.e. gap analysis) of crop wild relatives as a means to guide efficient and effective collecting activities.
The impact of local extinction on genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica: consequences for the conservation of plant genetic resources
Barrantes,Daniel; Macaya,Gabriel; Guarino,Luigi; Baudoin,Jean Pierre; Rocha,Oscar J;
Revista de Biología Tropical , 2008,
Abstract: plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. species may also colonize the same site on multiple occasions. here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (phaseolus lunatus) in the central valley of costa rica. we compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. however, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. recolonized locations showed the highest level of genetic differentiation (mean fst= 0.2769), followed by control locations (mean fst= 0.0576) and experimental locations (mean fst= 0.0189). similar findings were observed for nei?s genetic distance between samples (di,j= 0.1786, 0.0400, and 0.0037, respectively). our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. these findings also showed that control populations are not in equilibrium. implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. rev. biol. trop. 56 (3): 1023-1041. e
A Model to Evaluate the Thermal Conductivity of the Coral Reef in Tahiti
Alessio Guarino
Physics Research International , 2011, DOI: 10.1155/2011/679175
Abstract: Ohm's law models have been used in several works in geophysical prospecting but have never been used for coral reef. We adapted such a model to the barrier reef of Papeete (Tahiti island) in order to estimate of its thermal conductivity. We found the thermal conductivity of the barrier reef is about four times greater than that of the water. The results are then validated by the mean of experimental measurements.
Emancipazione e diritti umani nel pensiero di Boaventura de Sousa Santos
Guarino,Carmela;
Utopìa y Praxis Latinoamericana , 2009,
Abstract: boaventura de sousa santos makes a minute analysis of current society in which values such as equality and fraternity are eclipsed by the logic of neoliberal capitalism. law and modern science have contributed to this phenomenon through the determination of societies ever more unjust and excluding. the remedy for an imminent defeat, considers de sousa santos, is social emancipation, that is, an encounter between different civilizations, a process that permits mutual understanding among world citizens; therefore the concept of difference cannot be considered as a factor of separation and isolation, but rather as a factor of interchange and solidarity.
Adaptación y validación de la versión hispana del Cuestionario de Estilo Emocional
GUARINO,LETICIA;
Universitas Psychologica , 2011,
Abstract: the present paper reports the results of the spanish adaptation and validation of the emotional style questionnaire conducted with a sample of venezuelan university students. the original 56 items scale (roger & najarian, 1989; roger & nesshoever, 1987) measured four dimensions of emotional styles: rumination, emotional inhibition, aggresion control and benign control. however, based on the resivion of the scales, roger, guarino and olason (2000) propused a shorter version of 39 items, where only the rumination and emotional inhibition scales were maintained. the spanish version of this scale, jointly with other personality questionnaires and health vmeasures, was administered to a sample of 419 venezuelan university students and results showed the structure of the scale to be nearly identical to the english version, with adequate internal consistency. the concurrent and predictive validation study supports the theoretical structure for each dimension.
Adaptation and Validity of the Spanish Version of the Emotional Style Questionnaire
Leticia Guarino
Universitas Psychologica , 2011,
Abstract: The present paper reports the results of the Spanish adaptation and va- lidation of the Emotional Style Questionnaire conducted with a sample of Venezuelan university students. The original 56 items scale (Roger & Najarian, 1989; Roger & Nesshoever, 1987) measured four dimensions of emotional styles: rumination, emotional inhibition, aggresion control and benign control. However, based on the resivion of the scales, Roger, Guarino and Olason (2000) propused a shorter version of 39 items, where only the rumination and emotional inhibition scales were maintained. The Spanish version of this scale, jointly with other personality questionnaires and health vmeasures, was administered to a sample of 419 Venezuelan university students and results showed the structure of the scale to be nearly identical to the English version, with adequate internal consistency. The concurrent and predictive validation study supports the theoretical structure for each dimension.
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