1,084 research outputs found
STRUCTURALLY SUPPORTED CELL-LADEN SCAFFOLDS FOR BONE TISSUE REGENERATION
Due to challenges associated with current clinical techniques used to treat bone defects, there has been an increased focus on finding a tissue engineered solution. However, while great progress in this field has been achieved, researchers have yet to suitably combine the proper biological and structural environments needed to serve as a complete bone tissue substitute that is comparable to modern clinical solutions.
To achieve the goal of creating a model bone tissue substitute which could eventually serve as a viable therapy for bone trauma, be it caused by congenital medical conditions, age related diseases or high impact forces, three areas of the engineered construct architecture and composition were identified and studied in a successive fashion. First, a soft, biocompatible matrix within which cells could be encapsulated was studied, followed by an investigation on how to combine the soft matrix with a 3D printed structural frame. Finally, user-defined perfusable vasculature was added to the soft matrix in order to create a model bone tissue engineering construct capable of possible in vivo implantation.
In Chapter 2 of this work, osteoblast-like human osteosarcoma cells (Saos-2) were encapsulated within gelatin methacrylate (GelMA) hydrogels and the effect of the hydrogel density on cellular morphology and mineralization was investigated. It was found that the less dense hydrogels allowed for increased cell viability and spreading, while the denser gels appeared to encourage more mineral deposition on the construct periphery.
Building upon Chapter 2, Chapter 3 focused on the 3D printing of polycaprolactone (PCL) and composite PCL cages which could be combined with the soft GelMA matrices used for cellular encapsulation. It was found that while PCL and PCL composite cages could be reproducibly printed via a Makerbot 3D printer, the structural strengths did not surpass those of standard poly lactic acid (PLA) thermoplastic cages. Furthermore, it was demonstrated that the cell-laden GelMA hydrogels containing encapsulated Soas-2 cells could be incorporated with the 3D printed structures for potential bone tissue engineering applications.
In Chapter 4, a simpler version of the cages produced in Chapter 3 were combined with sacrificial 3D printed polyvinyl alcohol (PVA) pipes and the dense cell-laden hydrogels investigated in Chapter 2 to create structurally supported, cell-laden hydrogel constructs. It was found that encapsulated cells could be stimulated to deposit mineral in the centers of the constructs via direct perfusion. However, in a larger version of the construct containing multiple pipes, mineralization was impeded due to diffusion issues caused by individual channel mineralization.
Finally, in Chapter 5 future strategies to improve upon the structurally supported cell-laden hydrogels are discussed which would solve the issues found in Chapter 4. Additionally, potential in vivo applications for this system are explored
Organizational Climate and Commitment: A Case Study of an Urban Nonprofit Organization
This qualitative study investigates the relationship between the two constructs: Organizational Climate and Organizational Commitment.
Litwin and Stringer (1968) suggested that a molar model is needed to explain employee behavior and motivation. Climate was proposed as this molar construct. Research concerning Organizational Climate resulted in multiple definitions and little consensus concerning the number and use of multiple dimensions of this construct. The almost exclusive use of survey methods coupled with methodological confusion with Organizational Culture created difficulty with the use of this important construct.
Organizational Commitment research resulted in a number of competing definitions. Research by Meyer and Allen (1997) eventually led to continuance, normative, and affective commitment as a three-component model of Organizational Commitment. Despite suggestions in the literature, little research has been conducted explaining how Organizational Climate and Organizational Commitment constructs relate.
The study is composed of a pencil and paper survey. Indexes of the nine components of Organizational Climate based on McNabb and Sepic\u27s (1995) definitions were correlated with the three components of Organizational Commitment based on Meyer and Allen\u27s (1997) definitions. Focus group meetings and individual interviews were held to investigate worker understandings of both constructs. Open coding was used to identify themes from the interviews. This methodological triangulation within an instrumental case study resulted in findings of relationship between the two constructs by the application of each of the three methodologies. Survey results showed correlations between seven of the nine Organizational Climate dimensions and two of the components of Organizational Commitment. However, continuous commitment showed no correlations with any Organizational Climate dimension. Focus group and individual interviews indicated that workers perceive that a relationship between the two constructs definitely exists.
Findings from this study suggest a more extensive molar model than proposed by Litwin and Stringer (1968). Recommendations for nonprofit policy and practice are suggested. Future research in six areas is identified to expand this case study of an urban private nonprofit organization
Oriented circular dichroism of a class A amphipathic helix in aligned phospholipid multilayers
AbstractThe effect of lipid phase state on the orientation and conformation of a class A α-helical peptide on aligned lipid multilayers was examined using oriented circular dichroism spectroscopy. A comparison of oriented spectra in aligned peptide–lipid multilayers with CD spectra of unaligned peptide–lipid vesicle complexes is consistent with a preferential alignment of helices parallel to the membrane surface at temperatures above and below the main acyl-chain melting transition temperature of the phospholipid. Changes are observed in the oriented CD spectra with lipid phase state which are attributed to a subtle conformational change of the peptide on the lipid surface. The results are compared with available experimental data on membrane-active lytic and antimicrobial helical peptides
Epilogue: The Need for a New and Critical Democracy
Democratic critiques of neoliberalism have been comparatively rare, and positive democratic rejoinders to the social and political ruins of neoliberalism have been rarer. The question thus presents itself – what would an overtly democratic critique of neoliberalism look like and, beyond critique, what would a constructive democratic response to neoliberalism entail
Of Rights and Regulation
This chapter explores the development of social provisioning as a matter not of right but of democratic administration in France and the United States in the nineteenth century. The authors take issue with conventional chronologies of rights development, which see civil and political rights being developed in the eighteenth and nineteenth centuries, with social rights appearing in the twentieth. Such categories and sequencing obscure the ways in which democratic administrations took the problem of social provisioning seriously. A history of socio-economic rights cannot be distinguished from the less formal technologies of socio-economic regulation that were an integral part of the democratic question across the nineteenth century, and, in particular, the modernisation of regulatory governance. The democratisation of administrative powers precluded any sharp distinction among the political, the social and the economic. For better and for worse, this process took place through the building, rescaling and redefining of older, pre-democratic technologies of governance in response to what were perceived as pressing public problems
Dr. William D. Sawyer interview (2) conducted on October 8, 1984 about the Boonshoft School of Medicine at Wright State University
In this second interview Dr. William D. Sawyer, Dean of the Wright State University School of Medicine, continues his discussion of his background prior to coming to Wright State University. He compares medical education development between Thailand and the United States and his move back from Thailand to Indiana University in the United States. Dean Sawyer then goes on to describe his tenure as Chairman of the Department of Microbiology/Immunology at the School of Medicine at Indiana University.
Dean Sawyer discusses his administrative and leadership style at Indiana University and his challenges as Chairman.
In the third part of the interview Dean Sawyer recalls his thoughts on applying for the Deanship of a school of medicine. He recounts his ideas and thoughts on the subject of progressivism in medical education and how it related to his choice of medical schools. He then discusses his application process to Wright State University for the Deanship of the Wright State University School of Medicine
IMPACT OF HUMAN CHARACTERISTICS IN BASIC UNDERWATER DEMOLITION/SEAL (BUD/S) TRAINING PERFORMANCE
Reporting and clerical functions at Naval Special Warfare (NSW) Echelon IV commands are ripe for digitization, automation, and optimization. This study utilizes a restricted digitalized NSW dataset to showcase how “big data” in the context of SEAL training can be used to predict performance success of various Basic Underwater Demolition/SEAL (BUD/S) training evolutions. Our study focuses on multiple human characteristics and compares their correlation to evolution pass rates in training using Ordinary Least Squares (OLS) for our prediction model. From our initial regression analysis of over 232,000 data points, our findings indicate higher pass rates for BUD/S candidates who are older, married, and officers, as well as increased pass rates in individuals who were taller, lighter, and right-handed. Lower pass rates are found among minorities. The Black population had high fail rates in the evolutions that involve water activities. This study is an example of how long-term efficiencies could be gained from greater automation of data using simple software that could provide long-term benefit if captured in a more persistent and accurate manner. We advocate for the implementation of a more automated data/software collection system that can capture each student's training career in one cohesive data profile. Moving forward, NSW studies should continue to leverage the use of “big data” to optimize its performance across all domains of the force.Approved for public release. Distribution is unlimited.Lieutenant, United States NavyLieutenant, United States Nav
Women Farmers and E-Commerce Opportunities for 21st Century Marketing
Adding the Internet to your Business Recipe: Opportunity for Marketing in the 21st Century.
In the fall of 2006, the Center for Rural Studies (CRS) and Women’s Agricultural Network (WAgN) piloted a curriculum for agricultural entrepreneurs interested in incorporating e-commerce features – e.g. email lists, Web sites, online marketing, online ordering – into their operations. This broad definition of e-commerce reflects the integration of information technology and the Internet into business and marketing planning.
The workshops were held from 2006 to 2009. Each of the cycles provided insight into how to make future sessions more beneficial to participants. Offering the course even once/year during a period of rapid change in the available technology guaranteed that significant adjustments had to be made to the content each session.
This working paper addresses why we took on this challenge, why women farmers became the target audience, how the course was structured, and an overview of the results of the classes to date. Also included are lessons learned from the experience and next steps
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