Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties.

IntroductionMultipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials.MethodsIsolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types.ResultsThe cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.ConclusionsData demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies

Reagan and cutting the federal budget : how consistent was the pursuit?

President Reagan assumed office advocating an economic program based on tax and spending reductions. Achievement of these objectives, Reagan argued, would improve the American economy and result in balanced federal budgets. This thesis examines Reagan\u27s commitment to the spending restraint element of his program. I will analyze all of Reagan\u27s budgets and State of the Union addresses to determine how consistently he sought reductions in federal spending. Though Reagan\u27s commitment to budget reduction was evident, his selection of means to achieve the cuts was inconsistent. His proposed budget cuts varied in intensity, and Reagan failed to propose consistent reductions in many of his targeted budget functions. Reagan\u27s State of the Union messages varied from proposing substantial reductions to championing procedural devices to reduce the deficit. This thesis therefore argues that Reagan did not consistently seek the goal of reducing the federal government\u27s expenditures

Flutter suppression using eigenspace freedoms to meet requirements

A constrained optimization methodology has been developed which allows specific use of eigensystem freedoms to meet design requirements. A subset of the available eigenvector freedoms was employed. The eigenvector freedoms associated with a particular closed-loop eigenvalue are coefficients of basis vectors which span the subspace in which that closed-loop vector must lie. Design requirements are included as a vector of inequality constraints. The procedure was successfully applied to develop an unscheduled controller which stabilizes symmetric flutter of an aeroelastic vehicle to a dynamic pressure 44 percent above the open-loop flutter point. The design process proceeded from full-state feedback to the inclusion of a full-order observer to the selection of an eighth-order controller which preserved the full-state sensitivity characteristics. Only a subset of the design freedoms was utilized (i.e., assuming full-state feedback only four out of 26 eigenvectors were used, and no variations were made in the closed-loop eigenvalues). Utilization of additional eigensystem freedoms could further improve the controller

Residential fire detection

"Residential fires have become a significant problem throughout the U.S. The National Fire Protection Association (NFPA) estimates that in 1982 residential fires in the U.S. killed 4,940 persons and resulted in injury to 21,100 more. In addition, these residential fires accounted for an estimated $3,253,000,000 in property damage. Figure 1 shows the causes of residential fires as reported by the Federal Emergency Management Agency in its National Fire Incident Reporting System. The leading causes of fires in one-and-two family dwellings were heating (31 percent), cooking (15 percent), and incendiary or suspicious (10 percent). In residential properties, cigarettes are still the leading cause of accidental multiple death fires (those fires that are fatal to three or more persons) by a factor of two to one. Fires resulting from fixed or portable heating equipment-woodstoves, kerosene heaters, gas or electric cooking stoves, etc.,-are the second most common cause of accidental multipledeath fires in residential properties."--First page.David E. Baker (Department of Agricultural Engineering, College of Agriculture) and Paul Adams (Director, Missouri Fire and Rescue Training Institute, University of Missouri--Columbia)Revised 8/84/10

The Easy Case for Derivatives Use: Advocating a Corporate Fiduciary Duty to Use Derivatives

This Article hypothesizes that directors have a duty to shareholders to investigate and evaluate how derivatives could minimize risk to their organization. Even more, corporations have a duty to use derivatives if overall portfolio risk will thereby be reduced. Part I of this Article defines and describes the major types of derivatives and explains how and why they are used. Part II investigates the risks of derivatives, comparing these risks to other investment instruments. Part III introduces a new conceptualization of derivatives through exploration of three issues surrounding their use: (1) brokers\u27 liabilities to investors when financial losses result; (2) corporate liability to shareholders for losses; and (3) the possibility that in certain contexts, a corporation has a duty to its shareholders to use derivatives to manage business risk. Part IV proposes a risk management strategy designed to minimize the inherent risks of derivatives and to maximize their advantages in managing ordinary business risk. Part V concludes with a look to the future of derivatives. Derivatives, Duty, Risk Minimizatio

The Easy Case for Derivatives Use: Advocating a Corporate Fiduciary Duty to Use Derivatives

This Article hypothesizes that directors have a duty to shareholders to investigate and evaluate how derivatives could minimize risk to their organization. Even more, corporations have a duty to use derivatives if overall portfolio risk will thereby be reduced. Part I of this Article defines and describes the major types of derivatives and explains how and why they are used. Part II investigates the risks of derivatives, comparing these risks to other investment instruments. Part III introduces a new conceptualization of derivatives through exploration of three issues surrounding their use: (1) brokers\u27 liabilities to investors when financial losses result; (2) corporate liability to shareholders for losses; and (3) the possibility that in certain contexts, a corporation has a duty to its shareholders to use derivatives to manage business risk. Part IV proposes a risk management strategy designed to minimize the inherent risks of derivatives and to maximize their advantages in managing ordinary business risk. Part V concludes with a look to the future of derivatives. Derivatives, Duty, Risk Minimizatio

The Social Costs of an MTBE Ban in California

Resource /Energy Economics and Policy,

Refining regional organization of services in the UK to improve outcomes of pregnancies delivering at extremely low gestational age

Care for pregnant women and their infants at extremely low gestational ages challenges clinical teams. The continuing rise in survival at gestational ages below 25 weeks has prompted re-evaluation of practice guidelines within the UK and other countries. This paper describes the background data that have guided our practice, the approach that has been taken to deliver optimal outcomes for pregnancies delivering at extremely low gestational age in the UK, mainly through centralising care, and discusses the research and audit data that support our practice. In particular, we emphasize the importance of a coordinated perinatal approach to both mother and infant, and careful assessment of the risks to both, to ensure that we develop the highest quality personalized care for each family, supported by national quality improvement and research evidence