101
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Nguyen TQ, Schwartz BJ. Ionomeric control of interchain interactions, morphology, and the electronic properties of conjugated polymer solutions and films. J Chem Phys 2002. [DOI: 10.1063/1.1468215] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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102
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Schwartz BJ, Rossky PJ. An Exploration of the Relationship between Solvation Dynamics and Spectrally Determined Solvent Response Functions by Computer Simulation. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100010a004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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103
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Wallace-Williams SE, Schwartz BJ, Moeller S, Goldbeck RA, Yee WA, El-Bayoumi MA, Kliger DS. Excited state spectra and dynamics of phenyl-substituted butadienes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100052a011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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104
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Schwartz BJ, Rossky PJ. Dynamic Elements of Transient Spectral Hole Burning of the Hydrated Electron. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100068a001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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105
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Zhang JZ, Schwartz BJ, King JC, Harris CB. Ultrafast studies of photochromic spiropyrans in solution. J Am Chem Soc 2002. [DOI: 10.1021/ja00053a032] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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106
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Schwartz BJ, Peteanu LA, Harris CB. Direct observation of fast proton transfer: femtosecond photophysics of 3-hydroxyflavone. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100188a009] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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107
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Nguyen TQ, Yee RY, Schwartz BJ. Solution processing of conjugated polymers: the effects of polymer solubility on the morphology and electronic properties of semiconducting polymer films. J Photochem Photobiol A Chem 2001. [DOI: 10.1016/s1010-6030(01)00377-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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108
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Barthel ER, Martini IB, Schwartz BJ. How Does the Solvent Control Electron Transfer? Experimental and Theoretical Studies of the Simplest Charge Transfer Reaction. J Phys Chem B 2001. [DOI: 10.1021/jp011150e] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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109
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Martini IB, Barthel ER, Schwartz BJ. Optical control of electrons during electron transfer. Science 2001; 293:462-5. [PMID: 11463907 DOI: 10.1126/science.1061612] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The dynamics of electron transfer reactions in solution can be controlled with the use of a sequence of femtosecond laser pulses. In the charge transfer to solvent (CTTS) reaction of sodide (Na-) in tetrahydrofuran, an initial light pulse launched the CTTS reaction, ejecting an electron into either an immediate or a solvent-separated Na0:solvated electron contact pair. A second pulse was used to excite the electrons in the contact pairs, and a third pulse monitored the amount of Na- produced through the back electron transfer. Excitation of the electrons in immediate contact pairs shut off the back electron transfer, whereas excitation of the electrons in solvent-separated pairs both enhanced and hindered the back electron transfer.
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110
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Nguyen TQ, Schwartz BJ, Schaller RD, Johnson JC, Lee LF, Haber LH, Saykally RJ. Near-Field Scanning Optical Microscopy (NSOM) Studies of the Relationship between Interchain Interactions, Morphology, Photodamage, and Energy Transport in Conjugated Polymer Films. J Phys Chem B 2001. [DOI: 10.1021/jp004456e] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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111
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Martini IB, Barthel ER, Schwartz BJ. Mechanisms of the ultrafast production and recombination of solvated electrons in weakly polar fluids: Comparison of multiphoton ionization and detachment via the charge-transfer-to-solvent transition of Na− in THF. J Chem Phys 2000. [DOI: 10.1063/1.1328071] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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112
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Schwartz BJ, Sparrow FK, Heard NE, Thede BM. Simultaneous derivatization and trapping of volatile products from aqueous photolysis of thiamethoxam insecticide. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000; 48:4671-4675. [PMID: 11052717 DOI: 10.1021/jf990966y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An aqueous photolysis study was conducted with radiolabeled thiamethoxam, 4H-1,3,5-oxadiazin-2-imine, 3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro, to establish the relevance of aqueous photolysis as a transformation process for (14)C-[thiazolyl]-thiamethoxam. (14)C-[thiazolyl]-thiamethoxam was applied to sterile sodium acetate pH 5 buffer solution at a dose rate of approximately 10 ppm. The resulting samples were incubated for up to 30 days at 25 degrees C under irradiated and nonirradiated conditions. The irradiated samples were exposed to a 12-hour-on and 12-hour-off light cycle. Volatile fractions accounted for up to an average of 56.76% of the total dose for the irradiated incubations and <0.08% for the nonirradiated incubations. These fractions were proposed to be a mixture of carbonyl sulfide (COS) and isocyanic acid (CONH). Verification of these components was accomplished by trapping with cyclohexylamine and formation of the thiocarbamate and the isocyanic acid derivatives. A similar method of trapping thiocarbamate metabolites was reported (Chen and Casida, 1978) where filter paper saturated with isobutylamine in methanol was arranged to trap (14)COS and (14)CO(2) under a positive flow of O(2) at 25 degrees C. Mass spectroscopy of the derivatized components confirmed the presence of carbonyl sulfide as the cyclohexylamine thiocarbamate and of isocyanic acid as its cyclohexylamine derivative. Evidence from this study indicates that thiamethoxam degrades significantly under photolytic conditions.
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113
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Martini IB, Ma B, Da Ros T, Helgeson R, Wudl F, Schwartz BJ. Ultrafast competition between energy and charge transfer in a functionalized electron donor/fullerene derivative. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00890-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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114
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Aherne D, Tran V, Schwartz BJ. Nonlinear, Nonpolar Solvation Dynamics in Water: The Roles of Electrostriction and Solvent Translation in the Breakdown of Linear Response. J Phys Chem B 2000. [DOI: 10.1021/jp000326u] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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115
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Barthel ER, Martini IB, Schwartz BJ. Direct observation of charge-transfer-to-solvent (CTTS) reactions: Ultrafast dynamics of the photoexcited alkali metal anion sodide (Na−). J Chem Phys 2000. [DOI: 10.1063/1.481563] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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116
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Nguyen TQ, Wu J, Doan V, Schwartz BJ, Tolbert SH. Control of energy transfer in oriented conjugated polymer-mesoporous silica composites. Science 2000; 288:652-6. [PMID: 10784444 DOI: 10.1126/science.288.5466.652] [Citation(s) in RCA: 590] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Nanoscale architecture was used to control energy transfer in semiconducting polymers embedded in the channels of oriented, hexagonal nanoporous silica. Polarized femtosecond spectroscopies show that excitations migrate unidirectionally from aggregated, randomly oriented polymer segments outside the pores to isolated, aligned polymer chains within the pores. Energy migration along the conjugated polymer backbone occurred more slowly than Forster energy transfer between polymer chains. The different intrachain and interchain energy transfer time scales explain the behavior of conjugated polymers in a range of solution environments. The results provide insights for optimizing nanostructured materials for use in optoelectronic devices.
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117
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Nguyen TQ, Martini IB, Liu J, Schwartz BJ. Controlling Interchain Interactions in Conjugated Polymers: The Effects of Chain Morphology on Exciton−Exciton Annihilation and Aggregation in MEH−PPV Films. J Phys Chem B 1999. [DOI: 10.1021/jp993190c] [Citation(s) in RCA: 746] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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118
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Sastre Á, Gouloumis A, Vázquez P, Torres T, Doan V, Schwartz BJ, Wudl F, Echegoyen L, Rivera J. Phthalocyanine−Azacrown−Fullerene Multicomponent System: Synthesis, Photoinduced Processes, and Electrochemistry. Org Lett 1999. [DOI: 10.1021/ol991063t] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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119
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Tran V, Schwartz BJ. Role of Nonpolar Forces in Aqueous Solvation: Computer Simulation Study of Solvation Dynamics in Water Following Changes in Solute Size, Shape, and Charge. J Phys Chem B 1999. [DOI: 10.1021/jp990993r] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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120
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Nguyen TQ, Doan V, Schwartz BJ. Conjugated polymer aggregates in solution: Control of interchain interactions. J Chem Phys 1999. [DOI: 10.1063/1.478288] [Citation(s) in RCA: 641] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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121
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Witzgall G, Vrijen R, Yablonovitch E, Doan V, Schwartz BJ. Single-shot two-photon exposure of commercial photoresist for the production of three-dimensional structures. OPTICS LETTERS 1998; 23:1745-1747. [PMID: 18091901 DOI: 10.1364/ol.23.001745] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report the use of an amplified femtosecond laser for single-shot two-photon exposure of the commercial photoresist SU-8. By scanning of the focal volume through the interior of the resist, three-dimensional (3-D) structures are fabricated on a shot-by-shot basis. The 800-nm two-photon exposure and damage thresholds are 3.2 and 8.1TW/cm(2), respectively. The nonlinear nature of the two-photon process allows the production of features that are smaller than the diffraction limit. Preliminary results suggest that Ti:sapphire oscillators can achieve single-shot two-photon exposure with thresholds as low as 1.6TW/cm(2) at 700 nm, allowing 3-D structures to be constructed at megahertz repetition rates.
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122
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Doan V, Tran V, Schwartz BJ. Ultrafast intensity-dependent stimulated emission in conjugated polymers: The mechanism for line-narrowing. Chem Phys Lett 1998. [DOI: 10.1016/s0009-2614(98)00348-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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123
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Abstract
Behavioral managed care has been dominated by for-profit carve-out managed care organizations who deliver mental health and substance abuse services by reducing services and fees to the detriment of patients and providers. We offer a new model of managed care based on a provider-run, hospital-based approach in which provider groups contract directly with HMOs and eliminate the managed care organization intermediaries. This approach allows providers to maintain or regain control of the delivery of behavioral health services. A model is presented of an academically based organization which has achieved utilization patterns compatible with the demands of payors. Innovations in service delivery, network management and fiscal issues are reviewed.
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124
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Hide F, DÍaz-GarcÍa MA, Schwartz BJ, Heeger AJ. New Developments in the Photonic Applications of Conjugated Polymers. Acc Chem Res 1997. [DOI: 10.1021/ar950191o] [Citation(s) in RCA: 443] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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125
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Abstract
An academic department of psychiatry in New York City eliminated the need for behavioral managed care intermediaries by transforming itself from a fee-for-service system to a system able to engage in full-risk capitation contracts. The first step was to require health maintenance organizations to contract directly with the department. The department formed two legal entities, a behavioral management services organization for utilization management and a behavioral integrated provider association. The authors describe these entities and review the first year of operation, presenting data on enrollees, capitation rates, and service utilization for the first three contracts. The fundamental differences in the treatment model under managed care and under a fee-for-service system are highlighted. The authors conclude that by contracting directly with insurers on a full-risk capitation basis, departments of psychiatry will be better able to face the economic threats posed by the cost constraints inherent in managed care and maintain or re-establish their autonomy as care managers as well as high-quality care providers.
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