899 resultados para nanofibrous assembly
Resumo:
Development of an effective preservation strategy to fulfill off-the-shelf availability of tissue-engineered constructs (TECs) is demanded for realizing their clinical potential. In this study, the feasibility of vitrification, ice-free cryopreservation, for precultured ready-to-use TECs was evaluated. To prepare the TECs, bone marrow-derived porcine mesenchymal stromal cells (MSCs) were seeded in polycaprolactone-gelatin nanofibrous scaffolds and cultured for 3 weeks before vitrification treatment. The vitrification strategy developed, which involved exposure of the TECs to low concentrations of cryoprotectants followed by a vitrification solution and sterile packaging in a pouch with its subsequent immersion directly into liquid nitrogen, was accomplished within 11min. Stepwise removal of cryoprotectants, after warming in a 38 degrees C water bath, enabled rapid restoration of the TECs. Vitrification did not impair microstructure of the scaffold or cell viability. No significant differences were found between the vitrified and control TECs in cellular metabolic activity and proliferation on matched days and in the trends during 5 weeks of continuous culture postvitrification. Osteogenic differentiation ability in vitrified and control groups was similar. In conclusion, we have developed a time- and cost-efficient cryopreservation method that maintains integrity of the TECs while preserving MSCs viability and metabolic activity, and their ability to differentiate.
Resumo:
Parliamentary questions are the most popular and visible tool for making the executive accountable to the legislature. However, their use, purpose and effectiveness vary in different countries. In this study, 4023 parliamentary questions asked in the Uttar Pradesh State Legislative Assembly were analysed. The results show that half of the total members of the Assembly used this device. Contrary to findings in the Australian parliamentary system, there was no evidence of ‘Dorothy Dix’ and party influence on parliamentary questions. Furthermore, 30% of the questions were aimed at seeking information and 70% pressed for action. The government provided the required information in 95% of the questions in the former category but only took action in 37% in the latter category. The study concludes that parliamentary questions serve as an effective legislative tool in the Uttar Pradesh Legislature
Resumo:
The use of parliamentary questions is the most popular and visible tool in the hands of the Opposition as a means to make government accountable. Their main purpose is to seek information or press for action. Contemporary parliamentary literature from the UK, Canada, and Australia, however, suggests that parliamentary questions have lost their effectiveness. The literature points out that Question Time in parliaments has become a battle ground between Ruling and Opposition parties in their fight to gain maximum political advantage. In this context, the effectiveness of parliamentary questions in the Indian state legislatures has not been investigated. The aim of this study, therefore, is to analyse the use, purpose and effectiveness of parliamentary questions in the State Legislative Assembly of Uttar Pradesh (India) to explore differences, if any, between Ruling and Opposition parties. In this study, 4023 parliamentary questions asked in the Uttar Pradesh State Legislative Assembly were analysed. The effectiveness of answers was also analysed qualitatively. The results show that half of the total members of the Assembly used this device, out of which 60% of the questions were asked by the Opposition party members. 31% of the questions from the Opposition were seeking information and 69% were pressing for action. The government provided the required information in 96% of the questions in the former category and took action in only 35% of the latter category. Furthermore, 60% of the questions raised by the Opposition were related to constituency matters and the remaining 40% were related to policy issues or public welfare. Comparing the data with the ruling party, the results indicate that the use,purpose and effectiveness of parliamentary questions were similar to that of the Opposition except some minor differences. Surprisingly, there was no evidence of any ‘Dorothy Dix’ questions. The study concludes parliamentary question is an effective device in the Indian state of Uttar Pradesh.
Resumo:
The study investigated the effect on learning of four different instructional formats used to teach assembly procedures. Cognitive load and spatial information processing theories were used to generate the instructional material. The first group received a physical model to study, the second an isometric drawing, the third an isometric drawing plus a model and the fourth an orthographic drawing. Forty secondary school students were presented with the four different instructional formats and subsequently tested on an assembly task. The findings indicated that there may be evidence to argue that the model format which only required encoding of an already constructed three dimensional representation, caused less extraneous cognitive load compared to the isometric and the orthographic formats. No significant difference was found between the model and the isometric-plus-model formats on all measures because 80% of the students in the isometric-plus-model format chose to use the model format only. The model format also did not differ significantly from other groups in total time taken to complete the assembly, in number of correctly assembled pieces and in time spent on studying the tasks. However, the model group had significantly more correctly completed models and required fewer extra looks than the other groups.
Resumo:
Lean product design has the potential to reduce the overall product development time and cost and can improve the quality of a product. However, it has been found that no or little work has been carried out to provide an integrated framework of "lean design" and to quantitatively evaluate the effectiveness of lean practices/principles in product development process. This research proposed an integrated framework for lean design process and developed a dynamic decision making tool based on Methods Time Measurement (MTM) approach for assessing the impact of lean design on the assembly process. The proposed integrated lean framework demonstrates the lean processes to be followed in the product design and assembly process in order to achieve overall leanness. The decision tool consists of a central database, the lean design guidelines, and MTM analysis. Microsoft Access and C# are utilized to develop the user interface to use the MTM analysis as decision making tool. MTM based dynamic tool is capable of estimating the assembly time, costs of parts and labour of various alternatives of a design and hence is able to achieve optimum design. A case study is conducted to test and validate the functionality of the MTM Analysis as well as to verify the lean guidelines proposed for product development.
Resumo:
Stimulated by the efficacy of copper (I) catalysed Huisgen-type 1,3-dipolar cycloaddition of terminal alkynes and organic azides to generate 1,4-disubstituted 1,2,3-triazole derivatives, the importance of ‘click’ chemistry in the synthesis of organic and biological molecular systems is ever increasing.[1] The mild reaction conditions have also led to this reaction gaining favour in the construction of interlocked molecular architectures.[2-4] In the majority of cases however, the triazole group simply serves as a covalent linkage with no function in the resulting organic molecular framework. More recently a renewed interest has been shown in the transition metal coordination chemistry of triazole ligands.[3, 5, 6] In addition novel aryl macrocyclic and acyclic triazole based oligomers have been shown to recognise halide anions via cooperative triazole C5-H….anion hydrogen bonds.[7] In light of this it is surprising the potential anion binding affinity of the positively charged triazolium motif has not, with one notable exception,[8] been investigated. With the objective of manipulating the unique topological cavities of mechanically bonded molecules for anion recognition purposes, we have developed general methods of using anions to template the formation of interpenetrated and interlocked structures.[9-13] Herein we report the first examples of exploiting the 1,2,3-triazolium group in the anion templated formation of pseudorotaxane and rotaxane assemblies. In an unprecedented discovery the bromide anion is shown to be a superior templating reagent to chloride in the synthesis of a novel triazolium axle containing [2]rotaxane. Furthermore the resulting rotaxane interlocked host system exhibits the rare selectivity preference for bromide over chloride...