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Hydroxydicyclopentadiene (DCPD-OH) and some ester and ether derivatives were synthesized and used for the first time as ring-opening metathesis polymerization (ROMP) monomers to create cross-linked thermoset polymers with Ru-catalysts. The properties of this new family of polymers were measured mainly by means of TGA, DSC and DMA to compare them with those of polydicylopentadiene (pDCPD). The novel polymers showed thermal properties comparable to those of pDCPD; although glass transition temperatures were mainly reduced by the modifications. More importantly, tuneable physical properties, depending on the substituents attached, were obtained. Thus, a window towards many important applications is opened by making novel thermoset ROMP homopolymers and copolymers from monomers with significantly reduced odour.

Fast and accurate determination of lipid content in microalgal cultures is a required step for algal bioprocess development and optimization. An improved high-throughput Nile Red staining protocol using a microplate fluorescence reader is proposed, resulting in an increased correlation coefficient and a reduction in the relative standard deviation of 84% when compared to previously reported staining protocols. Differences in the staining efficacy of Nile Red among different algal strains were observed, even though the performance of the proposed method was found to be satisfactory for the different Trebouxiophyceae and Chlorophyceae microalgal cultures evaluated. Therefore, the proposed Nile Red method should only be used for evaluating lipid content variations in previously standardized strains. BODIPY 505/515 was evaluated as a potential substitute for Nile Red, but was found to be unsuitable as a quantitative stain for algal lipids in the microplate-based staining technique.

The synthesis of novel sulfur-chelated ruthenium benzylidenes afforded latent catalysts with a wider range of activities and new isomeric forms. A ruthenium complex with a tridentate ligand displayed latency for even one of the most reactive ROMP monomers, dicyclopentadiene, while a room temperature latent trifluoromethyl-substituted thioether derivative was shown to be the most active sulfur-chelated precatalyst to date in several metathesis reactions at higher temperatures. These new complexes widen the spectrum of activity for this family of catalysts, enabling several practical applications and enhancing the understanding for the mechanisms of activation in strongly chelated ruthenium alkylidenes.

Gradient-corrected (BP86) and hybrid (M06-L) density functional calculations were used to study the relative stability of cis and trans-dichloro X-chelated benzylidene ruthenium complexes (X = O, S, Se, N, P). Calculations in the gas phase differed from experimental results, predicting the trans-dichloro configuration as being more stable in every case. The addition of Poisson-Boltzmann (PBF) continuum approximation (dichloromethane) corrected the disagreement and afforded energies consistent with experimental results. Novel N, Se, and P chelated ruthenium olefin metathesis complexes were synthesized to evaluate calculation predictions. These findings reinforce the importance of including solvent corrections in DFT calculations of ruthenium metathesis catalysts and predict that stronger sigma donors as chelating atoms tend to electronically promote the unusual and less active cis-dichloro configuration.

A series of sulfur chelated dormant ruthenium olefin metathesis catalysts is presented. The catalysts prepared were shown to possess the uncommon cis-dichloro arrangement and were mostly inactive at room temperature. By systematically modifying the size of the substituent groups at the chelating sulfur atom, catalyst activity at different temperatures was significantly affected; more bulky substituents fomented activity at lower temperatures. The catalysts were also shown to be stable in solution and retained their catalytic activity even after being exposed to air for two weeks.

Several amino acid ligands were introduced into the Hoveyda–Grubbs 2nd generation complex by a facile anionic ligand exchange. The chiral pre-catalysts obtained displayed enantioselectivity in asymmetric ring-closing and ring-opening cross-metathesis reactions. Reduction of the lability of the carboxylate ligands was found to be cardinal for improving the observed enantiomeric product enrichment.

We studied the two photon absorption (TPA) properties of conjugated, symmetric bis( N -carbazolyl)-di-phenylpolyenes and bis( N -carbazolyl)-tri-phenylpolyenes. These novel molecules relate to the family of bis-donor-di-phenylpolynene recently shown [1] to possess very high two-photon absorption and fluorescence coefficients. The symmetric substitution of carbazole end-groups enhances the photostability of the molecules and at the same time maintains high TP coefficients ( δ max >1000 GM) as determined from two-photon fluorescence measurements with picosecond pulse excitation. A blue shift of the linear absorption and a red shift of the TP peak reflect a larger proximity of the one and two photon states in carbazole substituted chromophores. High fluorescence quantum yield (0.6–0.8) was found in most of the molecules studied. These results suggest that efficient and photo-stable TP chromophores with carbazole donors are promising materials for applications in two-photon imaging and sensitization.

The second order nonlinearity (β) of a series of organic π-conjugated molecules involving 1,3 indandione derivatives as an acceptor moiety has been measured. The effect of varying the donor from dialkylamino to N-carbazolyl substituents was examined. Despite the chemically similar nature of the two donors, a drastic reduction of electric field induced second harmonic (EFISH) β values for the molecules involving the N-carbazolyl substituents was detected. Quantum mechanical calculations indicate that the decrease in β values results from the presence of two overlapping transitions that contribute to β with opposite signs. Thus, the charge transfer band gives a positive βzzz contribution along the long molecular axis, while a transition essentially within the carbazole group provides a negative βzxx contribution to βEFISH. Therefore, these molecules can only be described with a two-dimensional model as opposed to the ‘classical’ one-dimensional model for NLO chromophores. Experimental verification of this hypothesis was provided by a combination of two experimental methods, EFISH and hyper Rayleigh scattering (HRS). Each technique probes a different combination of the β tensor elements, so we could deduce the two contributions.

The synthesis of a series of novel efficient TPA chromophores involving a carbazole moiety from N -( p -formyl)phenylcarbazole precursors and their linear absorption and fluorescent properties are described.

We have studied the two-photon absorption (TPA) and fluorescence properties of a series of phenylpolyenes with N-carbazolyl as donor end-groups in symmetric positions. The symmetric substitution of carbazole end-groups enhances the photostability of the molecules and maintains high TP coefficients. High fluorescence quantum efficiencies have been measured. The results suggest that TP chromophores with carbazole donors are promising materials for applications in two-photon imagin and sensitization. The study covers a broad excitation spectrum from 580nm to 820nm using a picosecond optical parametric source. We take advantage of the correlation between idler and signal waves emerging from the parametric generator and calibrate our results against Rhodamine B for which reliable data is available in the long wave range.

The second order nonlinearity of conjugated organic molecules involving, 1,3 indandione derivatives as an acceptor moiety has been studied. Varying the donor from dialkylamino to the chemically similar substituent, N- carbazolyl resulted in a drastic reduction of electric field induced second harmonic (beta) values. For some molecules, even a small negative value of (beta) was received. Quantum chemical calculations indicate that the decrease occurs as a result of two overlapping transitions, which contribute to (beta) with opposite signs. The charge transfer band gives a positive (beta) zzz along the molecular long axis, while a transition essentially within the carbazole moiety provides a negative (betazzz contribution to (betaEFISH. Thus, these molecules must be described with a 2D model as opposed to the 'classical' model of 1D nonlinear optical chromophores. The prediction of the 2D model was verified experimentally by using a combination of two methods, EFISH and Hyper-Rayleigh Scattering, which probe different combination of the (beta) tensor elements.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The occurrence of Zollinger-Ellison syndrome and neurofibromatosis in the same patient has theoretic and practical implications. It was believed that the overlap between MEN-I and MEN-2 was restricted to the parathyroid glands. Recently, however, several reports have described patients in whom characteristics of both MEN conditions existed ..-o The findings in our patient support the concept of a relationship between MEN-I and MEN-2. Adult patients with neurofibromatosis and hypertension are likely to have pheochromocytoma, but renal artery stenosis is a more common cause for hypertension in young patients with neurofibromatosis." We were unable to demonstrate a pheochromocytoma or renal artery stenosis in our patient. After total gastrectomy, the urinary vanillylmandelic acid content decreased abruptly, and the blood pressure and heart rate returned to normal limits. We cannot explain these changes. A similar return to normal of the blood pressure was described by Tomlinson," who reported that a hypertensive patient with the Zollinger-Ellison syndrome, a pituitary tumor, and hyperparathyroidism became normotensive after total gastrectomy and parathyroid resection.

• Chemotactic mediators, N -formyl-methionyl-leucyl-phenylalanine (FMLP) and the complement component C5a, were injected into the rabbit cornea, vitreous, and skin to induce a reaction resembling the "Arthus phenomenon." Injection of these mediators induced edema and granulocytic infiltration in the cornea, conjunctiva, and skin. These histologic changes resembled the inflammation produced by antigen (ovalbumin [OVA]) in specifically immunized rabbits. Keratitis began after two hours and subsided six hours after the injection. Conversely, the vitreous response started six hours after injection of FMLP and C5a and peaked between 24 and 48 hours. All the inflammatory reactions induced by FMLP, C5a, and rechallenge with antigen could be inhibited in varying degrees by subconjunctival injection of 0.1 mL of 10 -5 M dexamethasone, quinacrine, 5,8,11,14-eicosatetraynoic acid (ETYA), or indomethacin, agents that suppress different sites of chemotaxis of polymorphonuclear leukocytes. However, only the inflammation induced by FMLP could be inhibited by carbobenzoxy-phe-met, a competitive inhibitor of FMLP.

The new heterocyclic system, dibenzo[2,3:5,6]pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazole 3, which can be considered as a planar hybrid of carbazole and p-phenylenediamine, can readily be prepared from commercial precursors and possesses high thermal stability and strong electron donor properties comparable to tetra- and pentacene.