La Teorización Anclada (Grounded Theory) como Método de Investigación en Ciencias Sociales: En la encrucijada de dos paradigmas

Cuando aparece en los años 60, la teorización anclada TA (grounded theory) es presentada y recibida como innovación metodológica en ruptura con el modelo científico tradicional. Si bien es novedosa en varios aspectos, la TA es también tributaria de la sociología americana y del fenomenalismo, una doble herencia que fue y sigue siendo un tema de debates en las ciencias sociales. ¿Positivista o constructivista la TA, o simplemente híbrida? Después de haber presentado en qué consiste (o consistía) la TA, el artículo explora las avenidas filosóficas y metodológicas que se presentan a los investigadores decididos a utilizar la TA para llevar a cabo sus estudios

To Include or Not to Include Them? Realities, Challenges and Resistance to the Participation of People with Disabilities in Seniors’ Organizations

People with disabilities are often excluded from mainstream seniors’ organizations. A participatory action research project was undertaken in a seniors’ leisure association to better include members with disabilities. Results underline the importance of understanding the interaction of individual and environmental factors when looking to support the participation of seniors with disabilities

Diversity of Yersinia enterocolitica population in a slaughterhouse between 2009 and 2010 and discrimination ability of MLVA compared to PFGE

Yersiniosis is a human disease mainly due to the ingestion of raw or undercooked pork meat contaminated mostly with Yersinia enterocolitica (Ye). In France, 74.3% of pig batches at slaughterhouses carried pathogenic Ye. Among them, biotype 4 (BT4) and biotype 3 (BT3) were often recovered. PFGE is one of the most used methods to type Ye, with the restriction enzymes, XbaI and NotI. Nevertheless, MLVA method based on the diversity of six loci tends to replace PFGE; this method showed a higher discriminatory power in others studies. We investigated the genetic diversity of Ye strains isolated in 2009 and in 2010 in one pig slaughterhouse in France and compared the ability of MLVA and PFGE to discriminate the strains. During these two years, 335 isolates were collected from pigs. The BT4 represented 88.4% of the strains (296/335) and the BT3 only 11.6% (39/335). PFGE using XbaI enzyme allowed the identification of 12 XbaI-PFGE types and among them only one was common to the both surveys. Because the Simpson’s Index shows a low genetic diversity 31 BT4 strains and 39 BT3 strains were typed using MLVA. For BT3 strains, MLVA had the same index of diversity than PFGE (DI=0.472). In contrary, the index of diversity was significantly higher with MLVA (DI=0.871) than with PFGE (DI=0.665) for BT4 strains. Our study revealed that the population of Ye in pig varied over the time. The comparison of the both typing methods indicated that MLVA has a better discriminatory power than XbaI-PFGE method for BT4 strains but not for BT3 strains

In vitro characterization of the ability of Yersinia enterocolitica BT4 to colonize pigs and stainless steel surfaces

Yersiniosis is, after campylobacteriosis and salmonellosis, the third most frequently reported zoonosis in Europe. Humans become infected with Y. enterocolitica through the consumption of undercooked pork and raw food having been in contact with contaminated surfaces. Pigs, the main reservoir for human pathogenic strains, do not develop clinical signs. In France and worldwide, biotype 4 (BT4) is the biotype the most frequently isolated from both pigs and clinical yersiniosis. In this study, a collection of 26 pathogenic BT4 strains isolated from pig tonsils was used to investigate their ability to adhere and invade intestinal pig cells (IPEC-J2) and to adhere to abiotic surfaces (stainless steel coupons) using two in vitro tests. Regression analysis was performed between data sets obtained from IPECJ2 cells assays versus stainless steel assays. All BT4 strains were able to adhere and invade IPEC-J2 cells. However, the results showed heterogeneity between strains with respect to their ability to adhere to IPECJ2 cells, with a percentage of adhesion varying from 9% to more than 90%. The BT4 population displayed a more homogeneous ability to invade IPECJ2 cells with percentages varying from 10% to 26%. The BT4 strains displayed a great ability to adhere to the stainless steel surface, percentage of adhesion varying from 0.3% to 4.2%. No correlation was observed between IPEC-J2 cell adhesion, cell invasion and adhesion to the stainless steel surface (R² \u3c 0.02). In conclusion, these results reflect the ability of the different BT4 strains to colonize the intestinal tract of pigs and to contaminate the stainless steel surfaces of the food processing environment

VCU Day of Service Toolkit (VCU-DST)

This team designed and developed a digital Day of Service Toolkit (VCU-DST) to help facilitate the planning and execution of community service projects by VCU students, faculty and staff. The VCU-DST includes guidance and relevant procedures for all the aspects of planning needed to execute both large-scale and small-scale projects, including resources for strategic partnerships, financial planning and event logistics and evaluation. The VCU-DST is designed to be utilized for day-of-service projects planned and initiated by VCU students, student leaders, and organizations at all levels (undergraduate, graduate, and professional). The VCU-DST is designed to be flexible and adaptable, assisting in the planning of events of all types and sizes for execution at future dates as the students and their leaders see fit. At the completion of this project, the digital VCU-DST will be delivered to our sponsor, Joyce Lloyd, the faculty advisor for the Graduate Student Government Association. It will also be made available to student leadership and service organizations to assist them in planning their community service project

Hydrothermal processing of 3D-printed calcium phosphate scaffolds enhances bone formation in vivo: a comparison with biomimetic treatment

Hydrothermal (H) processes accelerate the hydrolysis reaction of a-tricalcium phosphate (a-TCP) compared to the long-established biomimetic (B) treatments. They are of special interest for patient-specific 3D-printed bone graft substitutes, where the manufacturing time represents a critical constraint. Altering the reaction conditions has implications for the physicochemical properties of the reaction product. However, the impact of the changes produced by the hydrothermal reaction on the in vivo performance was hitherto unknown. The present study compares the bone regeneration potential of 3D-printed a-TCP scaffolds hardened using these two treatments in rabbit condyle monocortical defects. Although both consolidation processes resulted in biocompatible scaffolds with osseointegrative and osteoconductive properties, the amount of newly formed bone increased by one third in the hydrothermal vs the biomimetic samples. B and H scaffolds consisted mostly of high specific surface area calcium-deficient hydroxyapatite (38 and 27 m2 g-1, respectively), with H samples containing also 10 wt.% ß-tricalcium phosphate (ß-TCP). The shrinkage produced during the consolidation process was shown to be very small in both cases, below 3%, and smaller for H than for B samples. The differences in the in vivo performance were mainly attributed to the distinct crystallisation nanostructures, which proved to have a major impact on permeability and protein adsorption capacity, using BSA as a model protein, with B samples being highly impermeable. Given the crucial role that soluble proteins play in osteogenesis, this is proposed to be a relevant factor behind the distinct in vivo performances observed for the two materials. Statement of significance The possibility to accelerate the consolidation of self-setting calcium phosphate inks through hydrothermal treatments has aroused great interest due to the associated advantages for the development of 3D-printed personalised bone scaffolds. Understanding the implications of this approach on the in vivo performance of the scaffolds is of paramount importance. This study compares, for the first time, this treatment to the long-established biomimetic setting strategy in terms of osteogenic potential in vivo in a rabbit model, and relates the results obtained to the physicochemical properties of the 3D-printed scaffolds (composition, crystallinity, nanostructure, nanoporosity) and their interaction with soluble proteins.Peer ReviewedPostprint (published version

Effects of White Leds on Growth and Phytonutrients of Outredgeous Romaine Lettuce When Supplemented with Various Monochromatic Wavelengths

Growing plants in space will be an essential part of sustaining astronauts during long-range missions. To drive photosynthesis, light-emitting diodes (LEDs) are becoming superior because of their efficiency, longevity, small size, safety, and wavelength versatility. Isolating the effects of certain wavelengths on plant growth when combined with white light is attracting attention. To optimize crop production/quality in space, this study has aimed to configure novel light recipes for the Advanced Plant Habitat currently aboard the International Space Station (ISS). By using white light as a background to maintain normal growth, the addition of monochromatic wavelengths provides a clearer understanding of how each part of the visible spectrum affects plant growth. By growing Outredgeous lettuce under six treatments of White (W) LEDs, W + blue (B), W+ green (G), W + red (R), W + far red (FR), and RGB + FR LEDs with ratios similar to natural sunlight, this investigation has assessed differences in biomass, morphology, chlorophyll, and the synthesis of key phytonutrients. The potential for Outredgeous to produce anthocyanin, lutein, potassium, magnesium, and iron is paramount to maintaining astronaut health. The crop responses to each treatment have been evaluated and the optimal LED combination for both plant yield and nutrient content will be presented

3D printing with star-shaped strands: a new approach to enhance in vivo bone regeneration

Concave surfaces have shown to promote bone regeneration in vivo. However, bone scaffolds obtained by direct ink writing, one of the most promising approaches for the fabrication of personalized bone grafts, consist mostly of convex surfaces, since they are obtained by microextrusion of cylindrical strands. By modifying the geometry of the nozzle, it is possible to print 3D structures composed of non-cylindrical strands and favor the presence of concave surfaces. In this work, we compare the in vivo performance of 3D-printed calcium phosphate scaffolds with either conventional cylindrical strands or star-shaped strands, in a rabbit femoral condyle model. Monocortical defects, drilled in contralateral positions, are randomly grafted with the two scaffold configurations, with identical composition. The samples are explanted eight weeks post-surgery and assessed by µ-CT and resin-embedded histological observations. The results reveal that the scaffolds containing star-shaped strands have better osteoconductive properties, guiding the newly formed bone faster towards the core of the scaffolds, and enhance bone regeneration, although the increase is not statistically significant (p > 0.05). This new approach represents a turning point towards the optimization of pore shape in 3D-printed bone grafts, further boosting the possibilities that direct ink writing technology offers for patient-specific applications.Peer ReviewedPostprint (published version

Acyclovir is activated into a HIV-1 reverse transcriptase inhibitor in herpesvirus-infected human tissues

For most viruses, there is a need for antimicrobials that target unique viral molecular properties. Acyclovir (ACV) is one such drug. It is activated into a human herpesvirus (HHV) DNA polymerase inhibitor exclusively by HHV kinases and, thus, does not suppress other viruses. Here, we show that ACV suppresses HIV-1 in HHV-coinfected human tissues, but not in HHV-free tissue or cell cultures. However, addition of HHV-6-infected cells renders these cultures sensitive to anti-HIV ACV activity. We hypothesized that such HIV suppression requires ACV phosphorylation by HHV kinases. Indeed, an ACV monophosphorylated prodrug bypasses the HHV requirement for HIV suppression. Furthermore, phosphorylated ACV directly inhibits HIV-1 reverse transcriptase (RT), terminating DNA chain elongation, and can trap RT at the termination site. These data suggest that ACV anti-HIV-1 activity may contribute to the response of HIV/HHV-coinfected patients to ACV treatment and could guide strategies for the development of new HIV-1 RT inhibitors