The use of polyelectrolytes in the field of supramolecular chemistry has flourished in recent years. Specifically, commercially available PAMAM dendrimers have attracted attention due to their large ...globular structures and high loading capacities. In this dissertation, we focus on using optical spectroscopy to study the intermolecular interactions responsible when these charged polyelectrolytes, mainly PAMAM dendrimers, act as encapsulating agents for guest molecules in aqueous solutions. We found electrostatics, hydrogen bonding, and interactions mediated by aromatic moieties in the guest molecules to be the main drivers to complex formation in these systems. Chapter 2 and Chapter 3 details original research directed toward gaining insight about the intermolecular interactions and properties of these systems. Upon the discovery that aromatic moieties in guest molecules play a role in increased binding affinity to the dendritic scaffold, we conducted experiments, presented in Chapter 4, examining the ability of these polyelectrolytes to act as solubilizing agents for hydrophobic molecules. Through extensive dissolution studies using aromatic hydrocarbon probes we propose that cationic polyelectrolytes increase solubilization of the aromatic hydrocarbons by interactions with the ammonium cations located on their surface. These studies afforded a more complete understanding of the fundamental intermolecular interactions involved when cationic polyelectrolytes function as supramolecular hosts, a role they commonly assume in many of their applications e.g. as drug delivery vectors. Macrocycles have also attracted attention due to their symmetrical architecture and high count of functional sites. Chapter 5 introduces the preliminary studies on the preparation of amine macrocycles that are important for studying dicarboxylate recognition in aqueous solvent using optical techniques. These studies provide the synthesis of a series of the desired amine macrocycles and their stoichiometry upon binding copper(II).
Triploids were successfully evolved in mulberry by diploidizing female gamete cells of Morus alba var. Kanva-2 with 0.2%, 0.3% and 0.4% colchicine treated for 8 hours for consecutive 3 days and by ...crossing them with monoecious diploid mutant. The triploids are characterized by increased growth and rooting habit; weight, size and water content of leaves, size of stomata and number of stomatal chloroplast and reduction in frequency of stomata per unit area and internodal distance have been recorded. Meiosis is highly irregular and characterized by the presence of a high frequency of trivalents and univalents. Various types of chromosomal associations, presence of tetravalents, unequal distribution and precocious movements of chromosomes, laggards, bridges at metaphase I and II, cytomixis at metaphase I and II, telophase I and II, dyads and tetrads stages and varying number of microspores have been frequently observed in the PMCs. The reduced pollen fertility has been attributed to various meiotic anomalies. Maintenance and commerical exploitation of triploids with desirable characters on large scale is feasible by vegetative multiplication.
The hydrolytic degradation of poly(hydroxybutyrate)-poly(hydroxyvalerate) (PHB-PHV) copolymers in the form of blends with the polysaccharides amylose, dextran, dextrin and sodium alginate, has been ...studied under a range of conditions (pH 2.3, 7.4 and 10.6 and at 37 degrees C and 70 degrees C). The hydrolytic degradation of the PHB-PHV copolymers was found to be dramatically affected by the presence of polysaccharides. Its progress was characterized by an initial increase in the wet weight, with concurrent decrease in the dry weight as the polysaccharides eroded from the matrix. Surface energy measurements and goniophotometry proved to be particularly useful in monitoring this stage of the degradation process. The concurrent increase in internal porosity leads to the eventual collapse of the matrix, a process which occurs, but less rapidly, in the degradation of the unblended PHB-PHV copolymers. Information obtained from molecular weight and crystallinity studies enabled a comprehensive profile of the overall degradation process to be built up.
Background There is uncertainty regarding the optimal adjunctive unfractionated heparin (UFH) regimen for percutaneous coronary intervention (PCI) in patients with non–ST-segment elevation acute ...coronary syndrome (NSTE-ACS) treated with fondaparinux. Objective The aim of this study is to evaluate the safety of 2 dose regimens of adjunctive intravenous UFH during PCI in high-risk patients with NSTE-ACS initially treated with fondaparinux and referred for early coronary angiography. Design This is an international prospective cohort study of approximately 4,000 high-risk patients presenting to hospital with unstable angina or non–ST-segment elevation myocardial infarction, treated with fondaparinux as initial medical therapy, and referred for early coronary angiography with a view to revascularization. Within this cohort, 2,000 patients undergoing PCI will be eligible for enrollment into a double-blind international randomized parallel-group trial evaluating standard activated clotting time (ACT)-guided doses of intravenous UFH versus a non–ACT-guided weight-adjusted low dose. The standard regimen uses an 85-U/kg bolus of UFH if there is no platelet glycoprotein IIb/IIIa (GpIIb-IIIa) inhibitor or 60 U/kg if GpIIb-IIIa inhibitor use is planned, with additional bolus guided by blinded ACT measurements. The low-dose regimen uses a 50 U/kg UFH bolus, irrespective of planned GpIIb-IIIa use. The primary outcome is the composite of peri-PCI major bleeding, minor bleeding, or major vascular access site complications. The assessment of net clinical benefit is a key secondary outcome: it addresses the composite of peri-PCI major bleeding with death, myocardial infarction, or target vessel revascularization at day 30. Conclusion FUTURA/OASIS 8 will help define the optimal UFH regimen as adjunct to PCI in high-risk NSTE-ACS patients treated with fondaparinux.
A new class of indazole-derived bradykinin B
1 antagonists and their structure–activity relationships (SAR) is reported. A number of compounds were found to have low-nanomolar affinity for the human ...B
1 receptor and possess acceptable P-gp and pharmacokinetics properties.
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