<p>During a cardiac cycle the cardiac walls change between contracted and relaxed and the valves open and close in response to pressure changes. This master thesis is a study of the changes in heart movement pattern caused by intravenous injections of Ca2+ or Nitroprusside. At Stanford University radiopaque markers have been surgically implanted in the walls and in the mitral valve of ovine hearts and 3D coordinates for each marker have been constantly measured during the cardiac cycle. By using MatLab, the volume and pressure of the left ventricle and several parameters related to the opening kinematics of the mitral valve have been analyzed. The results show, among others, that both Ca2+ and Nitroprusside reduce the volume and pressure of the left ventricle and that both substances decrease the size of the mitral annular ring. It was also shown that Ca2+ delays the opening of the mitral valve.</p>

There is an emerging interest in the development of sustainable materials with high performance. Cellulose is promising in this regard as it is a renewablere source with high specific properties, which can be utilized as strong reinforcements in novel biocomposites. However, to fully exploit the potential ofcellulose, its inherent hydrophilic character has to be modified in order toimprove the compatibility and interfacial adhesion with the more hydrophobicpolymer matrices commonly used in composites.In this study, the grafting of poly(ε-caprolactone) (PCL) and poly(L-lactide)(PLLA) from cellulose surfaces, via ring-opening polymerization (ROP) of ε-caprolactone and L-lactide, was investigated. Both macroscopic and nano-sizedcellulose were explored, such as filter paper, microfibrillated cellulose (MFC),MFC-films, and regenerated cellulose spheres. It was found that thehydrophobicity of the cellulose surfaces increased with longer graft lengths, andthat polymer grafting rendered a smoother surface morphology.To improve the grafting efficiency in the ROP from filter paper, both covalent(bis(methylol)propionic acid, bis-MPA) and physical pretreatment (xyloglucanbisMPA)were explored. The highest grafting efficiency was obtained with ROPfrom the bis-MPA modified filter papers, which significantly increased amountof polymer on the surface, i.e. the thickness of the grafted polymer layer.MFC was grafted with PCL to different molecular weights. The dispersability innon-polar solvent was obviously improved for the PCL grafted MFC, incomparison to neat MFC, and the stability of the MFC suspensions was better maintained with longer grafts. PCL based biocomposites were prepared from neat MFC and PCL grafted MFCwith different graft lengths. The polymer grafting improved the mechanical properties of the composites, and the best reinforcing effect was obtained when PCL grafted MFC with the longest grafts were used as reinforcement.A bilayer laminate consisting of PCL and MFC-films grafted with different PCL graft lengths displayed a gradual increase in the interfacial adhesion with increasing graft length.The effect of grafting on the adhesion was also investigated via colloidal probeatomic force microscopy at different temperatures and time in contact. A significant improvement in the adhesion was observed after polymer grafting. / QC 20100730

We report the application of our rhodium-catalyzed nucleophilic ring-opening methodology to the enantioselective synthesis of nitrogen-substituted polycyclic heterocycles. By using a cationic Rh(I) triflate catalyst in the presence of the chiral Josiphos ligand PPF-PtBu2, the ring opening reactions on dihydrooxaquinoline and dihydrooxaisoquinoline using different nucleophiles afford access to multiple dihydroquinolines and dihydroisoquinolones in high yield and high enantioselectivity (up to 99% total yield and >99%ee). A variety of nucleophiles were shown to be compatible with the catalytic system. The electronic effects in the new ring opening reactions were investigated using a variety of nucleophiles. It was found that reactivity and enantioselectivity of the ring opening products depends on the electronic effects as well as the position of the substituents on the substrates. Good yields and high ee of regioisomeric products are obtained using electron donating substituents, whereas electron withdrawing substituents decelerate the reactions.

We report the application of our rhodium-catalyzed nucleophilic ring-opening methodology to the enantioselective synthesis of nitrogen-substituted polycyclic heterocycles. By using a cationic Rh(I) triflate catalyst in the presence of the chiral Josiphos ligand PPF-PtBu2, the ring opening reactions on dihydrooxaquinoline and dihydrooxaisoquinoline using different nucleophiles afford access to multiple dihydroquinolines and dihydroisoquinolones in high yield and high enantioselectivity (up to 99% total yield and >99%ee). A variety of nucleophiles were shown to be compatible with the catalytic system. The electronic effects in the new ring opening reactions were investigated using a variety of nucleophiles. It was found that reactivity and enantioselectivity of the ring opening products depends on the electronic effects as well as the position of the substituents on the substrates. Good yields and high ee of regioisomeric products are obtained using electron donating substituents, whereas electron withdrawing substituents decelerate the reactions.

It was paramount for the English-speaking Caribbean to host a successful 2007 Cricket World Cup and field an outstanding West Indian cricket team for the international sporting mega-event. For CARICOM and the West Indies Cricket Board (WICB), there were two principle goals – first, to exhibit regional Caribbean identity, and second, to be triumphant under the leadership of the West Indian cricket team’s captain, Trinidadian Brian Lara. Identities are multifaceted and intricate, negotiated and renegotiated, based on a history of economic, political and cultural forces. This thesis interrogates Caribbean identity through textual analysis of the broadcast of the opening ceremony and regional newspaper coverage of the spectacle as well as ensuing events that were held in eight of the Caribbean countries from 11 March to 28 April 2007. The thesis questions whether this mega-event served as a catalyst toward Caribbean identity construction.

During a cardiac cycle the cardiac walls change between contracted and relaxed and the valves open and close in response to pressure changes. This master thesis is a study of the changes in heart movement pattern caused by intravenous injections of Ca2+ or Nitroprusside. At Stanford University radiopaque markers have been surgically implanted in the walls and in the mitral valve of ovine hearts and 3D coordinates for each marker have been constantly measured during the cardiac cycle. By using MatLab, the volume and pressure of the left ventricle and several parameters related to the opening kinematics of the mitral valve have been analyzed. The results show, among others, that both Ca2+ and Nitroprusside reduce the volume and pressure of the left ventricle and that both substances decrease the size of the mitral annular ring. It was also shown that Ca2+ delays the opening of the mitral valve.

Abstract This thesis is mainly to analyze China¡¦s development of sea power. There is always entangled relationship between the sea power and the national power. After the reforming and opening-up policy, China begin the development of sea power strategy, The motivation is to safeguard the interests of their national development and security. The economic development and demand for petroleum import. Since China¡¦s positively increased its maritime activities, and it will make huge impact to Asian-Pacific area. Keywords: Sea Power, reforming and opening-up policy, sea power strategy

A series of tetravalent zirconium and hafnium complexes were supported by diarylamido-phosphino [PNP]- (bis(o-diisopropylphosphinophenyl)amide) ligand. The reaction of MCl4(THF)2 (M = Zr, Hf) with [PNP]Li in toluene at room temperature generates [PNP]MCl3 as solid in 60 % yield. Polyalkyl complexes which are lack of £]-hydrogen have been achieved in synthesis of [PNP]MR3 (R = Me, CH2SiMe3) or [PNP]M(CH2SiMe3)2(E) (E = Cl, Me) since we could control the desired product from steric effect. An X-ray diffraction study of [PNP]ZrCl3 showed it to be a chloride-bridged binuclear species {[PNP]MCl2(£g-Cl)}2 in which both metal atoms are 7-coordinate whereas that of [PNP]MCl3(THF) revealed a mononuclear, 7-coordinate core structure. The phosphine fluxional exchange were found in those complexes, monitoring variable temperature 31P NMR, their fluxionality were calculated by line shape analysis. By heating [PNP]M(CH2SiMe3)2(Cl) in solution, we can afford new alkylidene complexes [PNP]M(Cl)(=CHSiMe3) via intramolecular £\-abstraction. Through Eyring plot analysis, the activation energy of [PNP]Zr(CH2SiMe3)2(Cl) £\-abstraction is ∆H‡ = 16.49(19) kcal/mol and ∆S‡ = −25.64(19) cal/mol•K; [PNP]Hf(CH2SiMe3)2(Cl) £\-abstraction is ∆H‡ = 18.70(36) kcal/mol and ∆S‡ = −23.12(36) cal/mol•K. The mixture [PNP]Hf(=CHSiMe3)(Cl) could not isolate with any purification, but [PNP]Hf(=CHSiMe3)(CH2SiMe3) obtained through directly alkylation. Here we also identified multiple alkylidene derivatives of [PNP]M(=CHSiMe3)(X) (X = Cl, CH2SiMe3). The X-ray structured and solution NMR data of those alkylidene complexes can be ascribed to evidence of £\-agostic interaction with metal center. A novel zwitterionic complex [PNP]Zr(£g2-CHSiMe3)2(AlMe2) was characterized by X-ray and been received a bisalkylidene complex which was synthesized through addition Lewies acid (AlMe3) into [PNP]Zr(=CHSiMe3)(CH2SiMe3). Group 4 alkylidene was acting as catalyst to metathesize ethylene or norbornene. The complexes [PNP]M(=CHSiMe3)(Cl) have highly streotic selectivity catalyst for ring-opening metathesis polymerization (ROMP) of norbornene. It is important to emphasize the great significance of the catalyst discoveries and improvements for both academic research and industry.

Biodegradable aliphatic polycarbonates are important components of non-toxic thermoplastic elastomers, which have a variety of medical applications. Industrially, aliphatic polycarbonates derived from six-membered cyclic carbonates such as trimethylene carbonate (TMC or 1,3-dioxan-2-one) are produced via ring-opening polymerization (ROP) processes in the presence of a tin catalyst. It is worth mentioning that TMC is readily obtained by transesterification of 1,3-propanediol with various reagents including phosgene and its derivatives. Therefore, it has been of great interest to investigate greener routes for the production of this important class of polymers. Toward this goal, the synthesis of aliphatic polycarbonates via the metal catalyzed alternative coupling of oxetanes and carbon dioxide represents an attractive alternative. The use of an abundant, inexpensive, non-toxic, and biorenewable resource, carbon dioxide, makes this method very valuable. Furthermore, in this reaction, the sixmembered cyclic carbonate byproduct, TMC, can also be ring-opened and transformed into the same polycarbonate. For over a decade, the Darensbourg research group has successfully utilized metal salen complexes as catalysts for the epoxide/CO2 copolymerization process. Hence, this dissertation focuses on the examination of these complexes as catalysts for the oxetane/CO2 copolymerization reaction and the further elucidation of its mechanism. Chromium(III) salen derivatives in the presence of an azide ion initiator were determined to be very effective catalysts for the coupling of oxetanes and carbon dioxide providing polycarbonates with minimal amounts of ether linkages. Kinetic and mechanistic investigations performed on this process suggested that copolymer formation proceeded by two routes. These are the direct enchainment of oxetane and CO2, and the intermediacy of trimethylene carbonate, which was observed as a minor product of the coupling reaction. Anion initiators which are good leaving groups, e.g. bromide and iodide, are effective at affording TMC, and hence, more polycarbonate can be formed by the ROP of preformed trimethylene carbonate. Research efforts at tuning the selectivity of the oxetane/CO2 coupling process for TMC and/or polycarbonate produced from the homopolymerization of preformed TMC have been performed using cobalt(II) salen derivatives along with anion initiators. Lastly, investigations of this process involving 3-methoxy-methyl-3-methyloxetane will be presented.

The work reported herein describes efforts to create ring-opening metathesis block copolymers and homopolymers. The block copolymers were studied to gain insight into the local nanoscale environment of a block copolymer thin film. Additionally, perylene containing homopolymers were characterized in light of their possible use as an n-type material. In the first section of the thesis, the synthesis of diblock copolymers consisting of two blocks with very different dynamics is described. The covalent attachment of a molecular rotor which is sensitive to its local environment allowed the study of the dynamics of the polymers in thin films. The emissive intensity as a function of temperature allowed us to see discontinuity in the rates of change, indicating a change in the local environment corresponding to the transition of the polymer from a glassy to rubbery state. The corresponding temperature, to this event, is known as the glass transition temperature, Tg. Additionally, a polymer featuring a covalently bound n-type molecule, perylene diimide, was synthesized. The photophysical properties, including aggregation in dilute solution, are described. The material is expected to demonstrate the ability to efficiently transport negative charge, acting as n-type material in organic electronics. / text