Search

Your search keyword '"Wasielewski M"' showing total 148 results
Start Over Author "Wasielewski M" Language english
148 results on '"Wasielewski M"'

7. Biomimetic Multifunctional Porous Chalcogels as Solar Fuel Catalysts

Author

Yuhas, B. D., Smeigh, A. L., Samuel, A. P. S., Shim, Y., Bag, S., Douvalis, A. P., Wasielewski, M. R., and Kanatzidis, M. G.

Subjects
hydrogen evolution, active-sites, molecular-structure, thiolate, analogs, systems, core, mossbauer, iron-sulfur clusters, proteins
Abstract

Biological systems that can capture and store solar energy are rich in a variety of chemical functionalities, incorporating light-harvesting components, electron-transfer cofactors, and redox-active catalysts into one supramolecule. Any artificial mimic of such systems designed for solar fuels production will require the integration of complex subunits into a larger architecture. We present porous chalcogenide frameworks that can contain both immobilized redox-active Fe4S4 clusters and light-harvesting photoredox dye molecules in close proximity. These multifunctional gels are shown to electrocatalytically reduce protons and carbon disulfide. In addition, incorporation of a photoredox agent into the chalcogels is shown to photochemically produce hydrogen. The gels have a high degree of synthetic flexibility, which should allow for a wide range of light-driven processes relevant to the production of solar fuels. J Am Chem Soc

Published
2011

11. Separation of the exchange and dipolar contributions to the spin-spin coupling in the donor-acceptor complex TAPD-ZnP-NQ.

Author

Est, A., Fuechsle, G., Stehlik, D., and Wasielewski, M.

Abstract

The donor-acceptor complex, 2-tetraalkylphenylenediamine-zinc porphyrin-2-naphthoquinone (TAPD-ZnP-NQ), is studied using transient EPR at K-band (24 GHz). Spin polarized spectra of the radical pair TAPD+.NQ−. and of the triplet state TAPD-3ZnP-NQ are observed simultaneously following light excitation of the complex at 30 K in frozen solutions 2-methyl-tetrahydrofuran and the liquid crystal BDH E7. In the liquid crystal, the complex is partially ordered and the spectra depend on the orientation of the sample with respect to the magnetic field. The orientational distribution function is obtained independently by simulating the spectra of the triplet state and assuming that the principal axes of the order matrix coincide with those of the inertia tensor as has been found for solutes in nematic phases. The spectra of TAPD+.NQ−. are analyzed on the basis of the coupled correlated radical pair (CCRP) model using an estimate of the geometry based on the X-ray crystal structures of the components and the independently obtained orientational distribution function. It is shown that the experimental spectra are consistent with the assumed geometry and that the exchange coupling, J, is approximately 0.1 mT. This value is at least two order of magnitude larger than that found in the analogous radical pair P+.Q−. in photosynthetic reaction centres. This difference is rationalized in terms of different mechanisms for the exchange coupling. [ABSTRACT FROM AUTHOR]

Published
1997
Full Text
View/download PDF

12. General discussion.

Author

Lunell, S., Iwasaki, M., Sevilla, M., Kevan, L., Klassen, N., Symons, M. C. R., Toriyama, K., Williams, F., Wasielewski, M. R., Siebrand, W., Cox, S. F. J., Roduner, E., Kemp, T. J., Davies, A. G., Albery, W. J., Weller, A., Bernhard, W., and Sevilla, M. D.

Published
1984
Full Text
View/download PDF

13. General discussion.

Author

Albery, W. J., Kemp, T. J., Symons, M. C. R., Weller, A., Iwasaki, M., Toriyama, K., Close, D., Wasielewski, M. R., Bernhard, W., Sevilla, M. D., Hüttermann, J., Bahnemann, D., Siebrand, W., Kevan, L., Brocklehurst, B., Williams, F., Molin, Yu. N., Jones, C. C., Clark, T., and Lunell, S.

Published
1984
Full Text
View/download PDF

14. General discussion.

Author

Symons, M. C. R., Kaptein, R., Hore, P. J., Albery, W. J., McLauchlan, K. A., Trifunac, A. D., Wasielewski, M. R., Weller, A., Molin, Yu. N., Brocklehurst, B., Iwasaki, M., Williams, F., Percival, P. W., Roduner, E., and Bahnemann, D.

Published
1984
Full Text
View/download PDF

16. Chemically regulating Rh(I)-Bodipy photoredox switches.

Author

Lifschitz, A. M., Mendez-Arroyo, J., McGuirk, C. M., Mirkin, C. A., Young, R. M., Roznyatovskiy, V. V., and Wasielewski, M. R.

Subjects
RHODIUM, BORON, DIPYRRINS, CATALYSIS, SWITCHING theory, PHOTOVOLTAIC cells, SUPRAMOLECULAR chemistry, ELECTROCHEMICAL analysis
Abstract

The ability of Rh(I) centers to undergo photoinduced electron transfer from discrete metal orbitals to Bodipy fluorophores is mediated through reversible coordination chemistry. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

28. Improvement in health-related quality of life after therapy with omeprazole in patients with coronary artery disease and recurrent angina-like chest pain. A double-blind, placebo-controlled trial of the SF-36 survey

Author

Kłopocka Maria, Majer Marcin, Fabisiak Jacek, Suppan Karol, Pulkowski Grzegorz, Budzyński Jacek, Galus-Pulkowska Beata, and Wasielewski Marcin

Subjects
quality of life, SF-36 questionnaire, chest pain, omeprazole, coronary artery disease, Computer applications to medicine. Medical informatics, R858-859.7
Abstract

Abstract Background Many patients with coronary artery disease (CAD) have overlapping gastroenterological causes of recurrent chest pain, mainly due to gastroesophageal reflux (GER) and aspirin-induced gastrointestinal tract damage. These symptoms can be alleviated by proton pump inhibitors (PPIs). The study addressed whether omeprazole treatment also affects general health-related quality of life (HRQL) in patients with CAD. Study 48 patients with more than 50% narrowing of the coronary arteries on angiography without clinically overt gastrointestinal symptoms were studied. In a double-blind, placebo-controlled, cross-over study design, patients were randomized to take omeprazole 20 mg bid or a placebo for two weeks, and then crossed over to the other study arm. The SF-36 questionnaire was completed before treatment and again after two weeks of therapy. Results Patients treated with omeprazole in comparison to the subjects taking the placebo had significantly greater values for the SF-36 survey (which relates to both physical and mental health), as well as for bodily pain, general health perception, and physical health. In comparison to the baseline values, therapy with omeprazole led to a significant increase in the three summarized health components: total SF-36; physical and mental health; and in the following detailed health concept scores: physical functioning, limitations due to physical health problems, bodily pain and emotional well-being. Conclusions A double dose of omeprazole improved the general HRQL in patients with CAD without severe gastrointestinal symptoms more effectively than the placebo.

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results