Banker Fees and Acquisition Premia for Targets in Cash Tender Offers: Challenges to the Popular Wisdom on Banker Conflicts

We analyze data on fees paid to investment bankers and acquisition premia paid for targets in cash tender offers. Our results are broadly consistent with the predictions of a benign view of the role of investment banks in advising acquisition targets. Fees to investment banks are correlated with attributes of transactions and target firms in ways that make sense if banks are being paid for processing information. The more contingent (and, therefore, risky) the fees, the higher they tend to be, all else held constant. Variation in acquisition premia also can be explained by fundamental deal attributes. Contrary to the jaundiced view of fairness opinions, greater fixity of fees is not associated with higher acquisition premia, and there is no evidence that investment banks are suborned by acquirors with whom they have had a prior banking relationship.

Cardiac regenerative medicine: insights from healthy and diseased engineered tissues

Cardiovascular disease remains the leading cause of mortality in the United States. Current tissue engineering approaches have fallen short of promoting fully functional cardiovascular cells and the post-myocardial infarction microenvironment is still not well understood. These gaps in knowledge are addressed in this dissertation through the development of in vitro engineered cardiac tissues using electroactive materials to enhance the differentiation of pluripotent stem cell derived cardiomyocytes and through the development of in vitro myocardial inflammation models dedicated to understanding cardiomyocytes and macrophages interactions. Specifically, piezoelectric poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) supports the attachment and survival of mouse embryonic stem cell derived cardiomyocytes (mES-CM) and endothelial cells (mES-EC). Characterization of mES-CM confirms expression of classical cardiac specific marker such as cTnT and Cx43, as well as efficient calcium handling properties when cultured on PVDF-TrFE including response to ryanodine receptor and β-adrenergic stimulation. MES-EC also retain their ability to uptake low density lipoprotein when cultured on PVDF-TrFE scaffolds and express classical endothelial cell specific markers such as eNOS and PECAM-1. Additionally, a novel graphene composite scaffold (PCL+G) exhibiting even distribution of graphene particles within the matrix allowing miniscule amounts of graphene to increase conductivity is developed and characterized. MES-CM seeded on conductive PCL+G scaffolds attach well and begin migrating into the scaffold matrix. They exhibit well-registered sarcomeres, express cardiac specific markers such as cTnT, MHC and Cx43 and spontaneous beat for up to two weeks. MES-CM on PCL+G scaffolds can be electrically paced and respond to ryanodine receptor and β-adrenergic stimulation. The combination of highly aligned fiber orientation and the presence of graphene promoted significantly improve calcium cycling efficiency by a fractional release of over 40%. Finally, in vitro myocardial inflammation models are developed to examine both direct and indirect co-culture of mES-CM with polarized macrophage subpopulations present in the post-MI microenvironment. Direct co-culture with macrophage subsets cause significant changes in mES-CM calcium handling function, especially in store operated calcium entry (SOCE), which is accompanied by significant increases in matricellular protein secretion, osteopontin (OPN). A pathway connecting OPN to SOCE response through ERK1/2 activation is analyzed through indirect co-culture with macrophage conditioned media and found to be affected by OPN inhibition, suggesting this pathway is involved with calcium homeostasis in the post-MI microenvironment, specifically in the pro-healing, anti-inflammatory phase. Taken together, the presented results expand the current state of research in cardiac regenerative medicine by demonstrating the potential of two electroactive biomaterials for the formation of functional cardiac tissues and by illuminating a novel target involved in changes in cardiomyocytes calcium homeostasis during post-MI healing through an in vitro engineered diseased model

Las modalidades de la contratación estatal

Con este trabajo se quiere explicar de manera práctica y sencilla las modalidades de contratación estatal con el fin de definir las funciones y responsabilidades de los servidores públicos, de tal forma que se agilicen los procedimientos de contratación para que las entidades puedan cumplir con sus metas, prevenir las prácticas corruptas y orientar en forma asertiva la gestión pública hacia el interés general

Decellularized Pancreatic Tissue

Diabetes mellitus is a pancreatic condition caused by either an autoimmune destruction of insulin producing beta cells or failing pancreatic beta cells. Current treatments address symptoms but do not successfully replace these malfunctioning tissues. Pancreas and islet transplantation are very limited due to the shortage of donors. The decellularization of pancreatic tissue provides a native tissue matrix, applicable for various tissue engineering investigations. Through the process of decellularization, it is possible for the extracellular matrix (ECM) to maintain the chemical and structural integrity of the original tissue. It can then be used as a scaffold material through the additions of different cell populations, including stem cells, allowing them to differentiate. Other methods include fabricating a native ECM powder from the decellularized tissue from which hydrogels can be constructed. This project involves the decellularization of an isolated rat pancreas. Using a static rocker and later a perfusion system set up, the pancreas sections will be decellularized using 0.5% sodium dodecyl sulfate (SDS) and 1% Triton X-100 buffers in order to remove all the cellular components from the pancreatic tissue. After decellularization, the pancreas tissue will be lyophilized and prepared into pancreas extracellular matrix powder. The powder can be used to form hydrogels, mimicking the pancreatic tissue. I have successfully decellularized pancreas sections and am currently quantifying decellularization efficiency by counting the remaining cellular nuclei using DAPI staining and ImageJ software. It is predicted that the native tissue matrix of the pancreas can serve as promising material in developing engineered pancreatic tissue

Self-interaction chromatography as a tool for optimizing conditions for membrane protein crystallization

The second virial coefficient, or B value, is a measurement of how well a protein interacts with itself in solution. These interactions can lead to protein crystallization or precipitation, depending on their strength, with a narrow range of B values (the `crystallization slot') being known to promote crystallization. A convenient method of determining the B value is by self-interaction chromatography. This paper describes how the light-harvesting complex 1-reaction centre core complex from Allochromatium vinosum yielded single straight-edged crystals after iterative cycles of self-interaction chromatography and crystallization. This process allowed the rapid screening of small molecules and detergents as crystallization additives. Here, a description is given of how self-interaction chromatography has been utilized to improve the crystallization conditions of a membrane protein

Biocompatibility of PCL-Graphene Nanostructured Scaffolds with Mouse Embryonic Stem Cell-derived Cardiomyocytes

Since adult cardiomyocytes are not readily available for clinical use, numerous efforts have been made to derive functional cardiomyocytes from pluripotent stem cells. [1,2]. A variety of cardiovascular tissue engineering strategies have been explored to develop engineered cardiac tissues for in vitro and in vivo applications utilizing fibrous tissue scaffolds, both single polymer scaffolds and hybrids of polymers with hydrogels, coatings or embedded materials[3-9]. While graphene, a single layer carbon crystal, has recently become a material of interest for tissue engineering applications including osteogenic, neural and stem cell differentiation [10-12], its potential for cardiac tissue engineering is yet unknown. The inherent electro-activity of the myocardium makes graphene an especially attractive option for cardiac tissue engineering due to its high electrical conductivity. Thus, a novel hybrid 3D scaffold with graphene has been developed and its effect on the function of stem cell derived cardiomyocytes is examined

Banker Fees and Acquisition Premia for Targets in Cash Tender Offers: Challenges to the Popular Wisdom on Banker Conflicts

We analyze data on fees paid to investment bankers and acquisition premia paid for targets in cash tender offers. Our results are broadly consistent with the predictions of a benign view of the role of investment banks in advising acquisition targets. Fees to investment banks are correlated with attributes of transactions and target firms in ways that make sense if banks are being paid for processing information. The more contingent (and, therefore, risky) the fees, the higher they tend to be, all else held constant. Variation in acquisition premia also can be explained by fundamental deal attributes. Contrary to the jaundiced view of fairness opinions, greater fixity of fees is not associated with higher acquisition premia, and there is no evidence that investment banks are suborned by acquirors with whom they have had a prior banking relationship