Dublin City University

About: Dublin City University is a education organization based out in Dublin, Ireland. It is known for research contribution in the topics: Machine translation & Laser. The organization has 5904 authors who have published 17178 publications receiving 389376 citations. The organization is also known as: National Institute for Higher Education, Dublin & DCU.

Thermal behavior and mechanical properties of physically crosslinked PVA/Gelatin hydrogels

Abstract: Poly (vinyl alcohol)/Gelatin hydrogels are under active investigation as potential vascular cell culture biomaterials, tissue models and vascular implants. The PVA/Gelatin hydrogels are physically crosslinked by the freeze-thaw technique, which is followed by a coagulation bath treatment. In this study, the thermal behavior of the gels was examined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Rheological measurement and uniaxial tensile tests revealed key mechanical properties. The role of polymer fraction in relation to these mechanical properties is explored. Gelatin has no significant effect on the thermal behavior of PVA, which indicates that no substantial change occurs in the PVA crystallite due to the presence of gelatin. The glass transition temperature, melting temperature, degree of crystallinity, polymer fraction, storage modulus (G') and ultimate strength of one freeze-thaw cycle (1FT) hydrogels are inferior to those of 3FT hydrogels. With coagulation, both 1FT and 3FT hydrogels shifted to a lower value of T(g), melting temperature and polymer fraction are further increased and the degree of crystallinity is depressed. The mechanical properties of 1FT, but not 3FT, were strengthened with coagulation treatment. This study gives a detailed investigation of the microstructure formation of PVA/Gelatin hydrogel in each stage of physical treatments which helps us to explain the role of physical treatments in tuning their physical properties for biomechanical applications.

Acquiring and sharing tacit knowledge in software development teams: An empirical study

Abstract: Context Sharing expert knowledge is a key process in developing software products. Since expert knowledge is mostly tacit, the acquisition and sharing of tacit knowledge along with the development of a transactive memory system (TMS) are significant factors in effective software teams. Objective We seek to enhance our understanding human factors in the software development process and provide support for the agile approach, particularly in its advocacy of social interaction, by answering two questions : How do software development teams acquire and share tacit knowledge ? What roles do tacit knowledge and transactive memory play in successful team performance ? Method A theoretical model describing the process for acquiring and sharing tacit knowledge and development of a TMS through social interaction is presented and a second predictive model addresses the two research questions above. The elements of the predictive model and other demographic variables were incorporated into a larger online survey for software development teams, completed by 46 software SMEs, consisting of 181 individual team members. Results Our results show that team tacit knowledge is acquired and shared directly through good quality social interactions and through the development of a TMS with quality of social interaction playing a greater role than transactive memory. Both TMS and team tacit knowledge predict effectiveness but not efficiency in software teams. Conclusion It is concluded that TMS and team tacit knowledge can differentiate between low- and high-performing teams in terms of effectiveness, where more effective teams have a competitive advantage in developing new products and bringing them to market. As face-to-face social interaction is key, collocated, functionally rich, domain expert teams are advocated rather than distributed teams, though arguably the team manager may be in a separate geographic location provided that there is frequent communication and effective use of issue tracking tools as in agile teams.

Steroid receptor RNA activator stimulates proliferation as well as apoptosis in vivo

Abstract: Steroid receptor RNA activator (SRA) is an RNA that coactivates steroid hormone receptor-mediated transcription in vitro. Its expression is strongly up-regulated in many human tumors of the breast, uterus, and ovary, suggesting a potential role in pathogenesis. To assess SRA function in vivo, a transgenic-mouse model was generated to enable robust human SRA expression by using the transcriptional activity of the mouse mammary tumor virus long terminal repeat. Transgenic SRA was expressed in the nuclei of luminal epithelial cells of the mammary gland and tissues of the male accessory sex glands. Distinctive evidence for SRA function in vivo was obtained from the elevated levels of estrogen-controlled expression of progesterone receptor in transgenic mammary glands. Although overexpression of SRA showed strong promoting activities on cellular proliferation and differentiation, no alterations progressed to malignancy. Epithelial hyperplasia was accompanied by increased apoptosis, and preneoplastic lesions were cleared by focal degenerative transformations. In bitransgenic mice, SRA also antagonized ras-induced tumor formation. This work indicates that although coactivation of steroid-dependent transcription by SRA is accompanied by a proliferative response, overexpression is not in itself sufficient to induce turmorigenesis. Our results underline an intricate relationship between the different physiological roles of steroid receptors in conjunction with the RNA activator in the regulation of development, tissue homeostasis, and reproduction.

Evolution of sweet taste perception in hummingbirds by transformation of the ancestral umami receptor

Abstract: Sensory systems define an animal's capacity for perception and can evolve to promote survival in new environmental niches. We have uncovered a noncanonical mechanism for sweet taste perception that evolved in hummingbirds since their divergence from insectivorous swifts, their closest relatives. We observed the widespread absence in birds of an essential subunit (T1R2) of the only known vertebrate sweet receptor, raising questions about how specialized nectar feeders such as hummingbirds sense sugars. Receptor expression studies revealed that the ancestral umami receptor (the T1R1-T1R3 heterodimer) was repurposed in hummingbirds to function as a carbohydrate receptor. Furthermore, the molecular recognition properties of T1R1-T1R3 guided taste behavior in captive and wild hummingbirds. We propose that changing taste receptor function enabled hummingbirds to perceive and use nectar, facilitating the massive radiation of hummingbird species.