No description available.

<p>Ventricular Assist Devices (VADs) are mechanical pumps used to off-load a deceased heart, primarily in late stage congestive heart failure patients. VAD employment may facilitate cardiac recovery, but most often provides time before a suitable heart transplant can be found. Lately, long term use VAD systems have been introduced as an alternative to a heart transplant.</p><p>Traditionally, design of VADs has employed either displacement based pump technologies or radial-flow pumps, also known as rotodynamic pumps. A displacement pump induces a mechanical force on a fluid contained within a defined space, hence giving it motion. Radial-flow pumps impart momentum to a fluid, most often by placing a rotating device in the fluid.</p><p>This thesis introduces a novel pumping concept, combining features from both displacement and radial-flow pumps. A first prototype, the Vivicor^TM pump, has been designed, fabricated and evaluated In Vitro, the results reported in this thesis.</p><p>The In Vitro evaluation of the Vivicor^TM pump provides evidence of a pump with mechanical self-regulation based on pump pre-load level, much like a displacement pump. The Vivicor^TM pump also displays pulsating outflow in combination with an inflow both during pump systole and diastole. The latter provides potential advantages over traditional displacement pumps as smaller cannulae or catheters can be used, facilitating miniaturization. Continuos filling throughout the pumping cycle also require less pressure to be exerted on the fluid, compared to displacement pumps, limiting the risk of mechanical damage to the pumped fluid. The In Vitro evaluation has also provided further insights on necessary design modifications in the second-generation Vivicor^TM prototype, currently planned. The Vivicor^TMpumping technology is highly interesting for further development and evaluation for use in ventricular assist applications.</p>

This research project compares different chemical and spectroscopic techniques aimed at finding a quick and cheap replacement for the measurement of digestibility of phosphorus (P) in different inorganic feed additives for pigs. This research yielded a comparison of the digestibility of different feed additives. P digestibility was determined from in vivo studies of pigs. The animal feed in the in vivo studies contained P levels below the nutrient requirements. The basal diet was a corn soybean meal base. Assessment was performed on 6 different inorganic P sources, rock phosphate (tricalcium phosphate (TCP)), meat and bone meal (MBM), mono/dicalcium phosphate (MDCP) and three different dicalcium phosphates (DCPs). Eight pigs where selected and placed into separate pens. Two were given basal diets and the other 6 diets were randomly selected and supplied with the different inorganic P sources. P digestibility was calculated by difference. The apparent P digestibility of the sources were: TCP at 46 %, the MBM at 85 %, MDCP at 71 % and three DCPs ranged from 49 % to 73 %. This substantiated that the apparent P digestibility in the major inorganic sources of P is significantly less than 100%. The in vitro or chemical methods of assessing phosphorus availability in animal feed included the commonly used feed extraction methods of water solubility and 2 % citric acid. These two methods showed significant differences between each other. Other chemical methods used included calcium chloride, ammonium acetate, sodium bicarbonate extractions, and a double extraction using hydrochloric acid (HCl) followed by sodium bicarbonate. The chemical methods showed non-significant correlation coefficients when compared to in vivo P digestibility of the six phosphate ingredients used. Infra-red spectroscopy is now commonly used in feed production for many other nutritional tests. NIR, although being able to obtain an R2 above 0.999 for correlation curves and factor prediction curves, could not obtain a self prediction of the calcium phosphates due to the large Mahalanobis Distance. P digestibility predicted by MIR showed close agreement with the in vivo P digestibility. Again due to the small number of ingredients tested in the pig trial, the prediction of digestibility using MIR could only be compared to it self. Hence MIR can only be used as an estimate until more data can be obtained. The P31 SS-MAS-NMR indicated one of the DCPs was made up of 3 or more P compounds by displaying 3 major peaks. All the P chemical shifts from the faeces had different positions to the P peaks in the ingredients, indicating some sort of change in the P form. Overall the chemical methods were unable to predict P digestibility, and while the spectroscopic techniques showed promise, they still require more work to examine many more feed additives.Invitro, invivo, phosphorus, digestibility, swine, infra-red spectroscopy, solid state NMR

Ventricular Assist Devices (VADs) are mechanical pumps used to off-load a deceased heart, primarily in late stage congestive heart failure patients. VAD employment may facilitate cardiac recovery, but most often provides time before a suitable heart transplant can be found. Lately, long term use VAD systems have been introduced as an alternative to a heart transplant. Traditionally, design of VADs has employed either displacement based pump technologies or radial-flow pumps, also known as rotodynamic pumps. A displacement pump induces a mechanical force on a fluid contained within a defined space, hence giving it motion. Radial-flow pumps impart momentum to a fluid, most often by placing a rotating device in the fluid. This thesis introduces a novel pumping concept, combining features from both displacement and radial-flow pumps. A first prototype, the VivicorTM pump, has been designed, fabricated and evaluated In Vitro, the results reported in this thesis. The In Vitro evaluation of the VivicorTM pump provides evidence of a pump with mechanical self-regulation based on pump pre-load level, much like a displacement pump. The VivicorTM pump also displays pulsating outflow in combination with an inflow both during pump systole and diastole. The latter provides potential advantages over traditional displacement pumps as smaller cannulae or catheters can be used, facilitating miniaturization. Continuos filling throughout the pumping cycle also require less pressure to be exerted on the fluid, compared to displacement pumps, limiting the risk of mechanical damage to the pumped fluid. The In Vitro evaluation has also provided further insights on necessary design modifications in the second-generation VivicorTM prototype, currently planned. The VivicorTM pumping technology is highly interesting for further development and evaluation for use in ventricular assist applications. / QC 20101129

Damage to dura mater may occur during intracranial or spinal surgeries, which can result in cerebrospinal fluid leakage as well as other potentially fatal physiological changes. As a result, biological scaffolds derived from xenogeneic materials are typically used to repair and regenerate dura mater post intracranial or spinal surgeries. In this study we explore the mechanics, structure, and immunological capacity of xenogeneic dura mater to be considered as a replacement for human dura. A comparative analysis is done between native porcine dura and a commercially available bovine collagen-based dura graft. Native porcine dura mater was decellularized and subjected to mechanical and histological analysis. Our decellularized porcine dura was able to maintain the overall morphological/structural integrity and held an increased extensibility without sacrificing strength, which provides a solid foundation as a functional grafting material. The histological observations showed that the orientation of fibers was maintained after decellularization. We investigated the biocompatibility of native and decellularized porcine dura reseeded with fibroblast cells for in vitro study. Cell proliferation, cell viability, and mechanical properties of dural grafts were evaluated post reseeding on days 3, 7, and 14. Live-dead staining and resazurin salts quantified cell viability and cell proliferation, respectively. This in vitro study showed that the acellular porcine dural graft provided a favorable environment for rat fibroblast cell infiltration. The results of micro indentation testing show that the cell-seeded porcine dural graft provides a favorable environment for rat fibroblast cell infiltration. The mechanics and biocompatibility results provide promising insight for the potential use of porcine dura in future cranial dura mater graft applications. Lastly, a subcutaneous in vivo study of dura graft compared with the market available Lyoplant®. Grafts were evaluated for inflammation by evaluating macrophage and leukocyte invasion on 3, 7, and 14 days post implantation. Histological analysis of both implants revealed macrophage (and leukocyte infiltration, supporting reabsorption, and thus encouraging the regeneration at 14 days. Cell markers also revealed that inflammation and leukocytes decreased as the number of days increased. Future work will involve a long-term subcutaneous implantation up to 30 days and 60 days to determine the long-term immune response.

No description available.

Embryonic stem (ES) cells offer a valuable source for generating insulin-producing cells. However, current differentiation protocols often result in heterogeneous cell populations of various developmental stages. Here we show the activin A-induced differentiation of mouse ES cells carrying a homologous dsRed-IRES-puromycin knock-in within the Sox17 locus into the endoderm lineage. Sox17-expressing cells were selected by fluorescence-assisted cell sorting (FACS) and characterized at the transcript and protein level. Treatment of ES cells with high concentrations of activin A for 10 days resulted in up to 19% Sox17-positive cells selected by FACS. Isolated Sox17-positive cells were characterized by defini- tive endoderm-specific Sox17/Cxcr4/Foxa2 transcripts, but lacked pluripotency-associated Oct4 mRNA and protein. The Sox17-expressing cells showed downregulation of extraembryonic endoderm (Sox7, Afp, Sdf1)-, mesoderm (Foxf1, Meox1)- and ectoderm (Pax6, NeuroD6)-specific transcripts. The presence of Hnf4α, Hes1 and Pdx1 mRNA demonstrated the expression of primitive gut/foregut cell-specific markers. Ngn3, Nkx6.1 and Nkx2.2 transcripts in Sox17-positive cells were determined as properties of pancreatic endocrine progenitors. Immunocytochemistry of activin A-induced Sox17-positive embryoid bodies revealed coexpression of Cxcr4 and Foxa2. Moreover, the histochemical demonstration of E-cadherin-, Cxcr4-, Sox9-, Hnf1β- and Ngn3-positive epithelial-like structures underlined the potential of Sox17-positive cells to further differentiate into the pancreatic lineage. By reducing the heterogeneity of the ES cell progeny, Sox17-expressing cells are a suitable model to evaluate the effects of growth and differentiation factors and of culture conditions to delineate the differentiation process for the generation of pancreatic cells in vitro. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Peste des petits ruminants virus (PPRV) belongs to the family paramyxoviridae which comprises non segmented negative sense RNA viruses including measles and rinderpest virus. PPRV is the causative agent of peste des petits rumaninats disease (also known as sheep or goat plague disease) in small ruminants. The viral genome contains a non segmented negative sense RNA encapsidated by viral encoded nucleocapsid protein (N-RNA). Viral transcription is carried out by the virus encoded RNA dependent RNA polymerase complex represented by the large protein L and phosphoprotein P. Viral transcription begins at the 3’ end of the genome synthesising all the viral transcripts (3’-N-P-M-F-HN-L-5’). A remarkable feature common to all members of Paramyxoviridae family is the gradient of transcription from 3’ end to the 5’ end due to attenuation of polymerase transcription at each gene junction. The objectives of the present study are characterization of peste des petits ruminants virus transcription and the associated activities required for post transcriptional modification of viral mRNA. In addition, an attempt has been made to develop in vitro transcription with heterologous combination of PPRV and RPV polymerase proteins. The first reaction in capping involves removal of γ-phosphate from triphosphate ended precursor mRNA by RNA triphosphatase. The domain having RNA triphosphatase activity within the L protein has been identified and expressed independently in E. coli. The details of the objectives are presented below. 1. Development of in vitro transcription system for PPRV mRNA synthesis In order to develop an in vitro transcription reconstitution system for PPRV, the viral RNP complex comprising large (L), phospho (P) and N protein encapsidating viral genomic RNA was purified from virus infected Vero cells. The in vitro transcription reconstituted system with RNP complex was able to synthesise all the viral mRNA as analysed by RT-PCR. As a control, total RNA from virus infected cells was isolated and analysed by RT-PCR. In order to refine the in vitro transcription system, separately expressed recombinant polymerase complex was used to reconstitute transcriptional activity in vitro. For this,viral genomic RNA (N-RNA) was purified from PPRV infected cells using CsCl density gradient centrifugation. The recombinant baculovirus for PPRV P protein was earlier generated in the lab. A recombinant baculovirus harbouring the L gene of PPRV was generated in the present study (described in part one). The viral RNA polymerase consisting of L-P complex was expressed in Sf21 insect cells and partially purified by ultra centrifugation on 5-20% glycerol gradient. Glycerol gradient fraction containing the L-P complex was found to be active in the in vitro transcription reconstitution system. Further quantitation of transcripts made in vitro and in infected cells has been carried out by real time PCR. Notably, the gradient of polarity of transcription of viral mRNA observed in vitro with the partially purified recombinant L-P complex was similar to the gradient observed in infected cells. Host proteins have been shown to modulate the transcription of many paramyxoviruses. In order to test the role of host factors, uninfected cell lysate of Vero cells was added to the in vitro transcription reaction and the transcript level was measured by real time PCR. The result showed an increase in the transcription by addition of host proteins suggesting the involvement of host factors in viral transcription. Further, the newly developed in vitro reconstitution system was used to test if recombinant L and P proteins of RPV can functionally replace PPRV L and P protein in the in vitro transcription complementation assay. The result presented in part one indicates that the L or P protein of PPRV can be replaced by RPV L and P protein in heterologous transcription reconstitution system ,with a reduced efficiency. However, the homologous polymerase complex of RPV failed to recognise the N-RNA genomic template of PPRV. 2. RNA triphosphatase activity of PPRV L protein and identification of RNA triphosphatase domain Post transcriptional modification of mRNA such as capping and methylation determines the translatability of viral mRNA by cellular ribosome. In negative sense RNA viruses, synthesis of viral mRNA is carried out by the viral encoded RNA polymerase in the host cell cytoplasm. Since the host capping and methylation machinery is localized to the nucleus, viruses should either encode their own mRNA modification enzymes or adopt alternative methods as has been reported for orthomyxoviruses (cap snatching) and picornaviruses (presence of IRES element). In order to test, if PPRV RNA polymerase possesses any of the capping activities, the RNP complex containing the viral N-RNA and RNA polymerase (L-P) were purified from virion. Using the purified RNP complex, the first activity required for mRNA capping, RNA triphosphatase was tested and the results are described in part two. RNP complex purified from virion showed both RNA triphosphatase (RTPase) activity. The RNA triphosphatase from viruses, fungi and other eukaryotes have been classified into two groups, metal dependent and metal independent. The cleavage of the γ-phosphate from triphosphate ended precursor mRNA by L protein of PPRV was found to be metal dependent. So, by the metal dependency of the RTPase reaction, PPRV L protein was assigned to the metal dependent RTPase tunnel family. One of the key features of metal dependent RTPase group members is the ability to hydrolyse γ-β phosphoanhydride bond of NTPs. PPRV L protein associated with RNP complex also was also able to cleave γ-β phosphoanhydride bond of NTPs. Owing to the large size of L protein (240 KDa), it is conceivable that the L protein functions in a modular fashion for different activities pertaining to mRNA synthesis and post transcriptional modification. Sequence comparison of L proteins from different morbilliviruses revealed the presence of three conserved domains namely domain I (aa 1-606), domain II (aa 650-1694) and domain III (aa 1717-2183). Domain II has the catalytic motif for viral RNA dependent RNA polymerase. Multiple sequence alignment of PPRV L protein with known RNA triphosphatases predicted a two hundred amino acid long region on L protein comprising the C terminus of domain II and N terminus of DIII as a possible candidate for RNA triphosphatase domain. The above predicted domain was cloned and expressed in E. coli. The ability of the purified recombinant RTPase domain to cleave γ-β phosphoanhydride bond of RNA was tested. The results described in part two suggest that the predicted RTPase domain has RNA triphosphatase activity. In addition to RNA triphosphatase, the RTPase domain also has the NTPase activity. The RNA triphosphatase of DNA viruses, yeasts and other fungi have three motifs essential for enzyme activity. Motif A and motif C are rich in glutamate and are involved in metal binding. Motif B is rich in basic amino acids and forms the centre for catalysis. The glutamate residue (E1647) of motif A of PPRV L protein RTPase domain was converted to alanine and the loss of RTPase activity was assessed. The results summarised in appendix 1 shows that the E1647A mutant has reduced RNA triphosphatase and NTPase activity.

Embryonic stem (ES) cells offer a valuable source for generating insulin-producing cells. However, current differentiation protocols often result in heterogeneous cell populations of various developmental stages. Here we show the activin A-induced differentiation of mouse ES cells carrying a homologous dsRed-IRES-puromycin knock-in within the Sox17 locus into the endoderm lineage. Sox17-expressing cells were selected by fluorescence-assisted cell sorting (FACS) and characterized at the transcript and protein level. Treatment of ES cells with high concentrations of activin A for 10 days resulted in up to 19% Sox17-positive cells selected by FACS. Isolated Sox17-positive cells were characterized by defini- tive endoderm-specific Sox17/Cxcr4/Foxa2 transcripts, but lacked pluripotency-associated Oct4 mRNA and protein. The Sox17-expressing cells showed downregulation of extraembryonic endoderm (Sox7, Afp, Sdf1)-, mesoderm (Foxf1, Meox1)- and ectoderm (Pax6, NeuroD6)-specific transcripts. The presence of Hnf4α, Hes1 and Pdx1 mRNA demonstrated the expression of primitive gut/foregut cell-specific markers. Ngn3, Nkx6.1 and Nkx2.2 transcripts in Sox17-positive cells were determined as properties of pancreatic endocrine progenitors. Immunocytochemistry of activin A-induced Sox17-positive embryoid bodies revealed coexpression of Cxcr4 and Foxa2. Moreover, the histochemical demonstration of E-cadherin-, Cxcr4-, Sox9-, Hnf1β- and Ngn3-positive epithelial-like structures underlined the potential of Sox17-positive cells to further differentiate into the pancreatic lineage. By reducing the heterogeneity of the ES cell progeny, Sox17-expressing cells are a suitable model to evaluate the effects of growth and differentiation factors and of culture conditions to delineate the differentiation process for the generation of pancreatic cells in vitro. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Dan Beaty (1937-2002) was a prolific composer, pianist, researcher, educator, and writer. His large compositional output included chamber works, choral works, songs, orchestral pieces, electronic music, and keyboard works. Beaty was well versed in traditional Western music as well as the more avant-garde and perplexing idioms of the twentieth century. Beaty's compositions reflect the many fascinating, if not always popular, musical trends of his time. His music encompasses styles from serial to jazz, shows compositional influences from Arnold Schoenberg to Indonesian music, and demonstrates thought-provoking and highly intellectual craftsmanship. This document explores several of Beaty's songs through a discussion of the composer's life and compositional process. Songs included in this document are Three Weeks Songs, October, November, A Sappho Lyric, Love Song, That Night When Joy Began, and War Lyrics. This document was written to accompany the author's DMA Lecture-Recital at the University of North Texas. Unfortunately, Beaty's vocal music was never published and is mostly unknown. One goal of the project was to initiate interest in Beaty's songs. Through this document, Lecture-Recital, and additional performances, considerable strides have been made to bring Beaty's songs to new audiences throughout the United States. In addition, the author has received permission from the Beaty family to publish Dan Beaty's songs.