Ultrafast dynamics of solvation: the story so far

The presence of solvent molecules in the vicinity of a solute affects a variety of processes in chemistry and biology, and thus one would like to have a physical picture of how solvation works. Although there are many structurally sensitive spectroscopic tools to investigate the role of solvent molecules in chemical processes, real time measurements of the dynamics of solvation had to wait for the development of pulsed laser spectroscopies with femtosecond time-resolution. This review describes applications of ultrafast spectroscopy to the study of solvation dynamics. At third order, we review resonant and non-resonant probes of solvation dynamics, with a focus on the study of simple and complex liquids. Fifth-order Raman spectroscopies are also reviewed, focusing on the insights these techniques give into the role of the solvent in chemical reactions and the anharmonic nature of the liquid state.A presença de moléculas de solvente na vizinhança de um soluto afeta uma variedade de processos em química e biologia, e por isso é interessante obter uma descrição física de como funciona a solvatação. Embora existam muitas ferramentas espectroscópicas estruturalmente sensíveis para a investigação do papel de moléculas de solvente em processos químicos, a medida em tempo real da dinâmica de solvatação somente tornou-se possível após o desenvolvimento de espectroscopias a laser pulsado com resolução temporal de femtossegundos. Esta revisão descreve aplicações da espectroscopia ultra-rápida ao estudo da dinâmica de solvatação. A nível de terceira ordem, discutimos a dinâmica de solvatação com técnicas ressonantes e não-ressonantes, com um foco no estudo de líquidos simples e complexos. Espectroscopias Raman de quinta ordem também são apresentadas, sendo que o enfoque dá-se no novo entendimento que estas técnicas fornecem com relação ao papel do solvente em reações químicas e à natureza anarmônica do estado líquido.21892204Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Characterizing slow photochemical reaction kinetics by enhanced sampling of rare events with capillary optical fibers and Kramers' theory

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCharacterization of slow chemical reactions is essential for assessing catalytic efficiency in chemistry and biology. [GRAPHIC] Traditionally, chemical reaction rates are obtained from population relaxation kinetics measurements and the Arrhenius equation. Unfortunately, it is difficult to use this approach to characterize reactions wherein concentrations change slowly. Thus, it is interesting to see whether a dynamical view of chemical reactions may be used to obtain the reaction rates of slow processes. In the present work, we perform Brownian dynamics simulations of an asymmetric double-well potential to investigate how enhanced sampling of barrier crossing at transition states improves the characterization of reaction rate constants. We then present the design of a liquid-filled capillary optical fiber-based fluorescence spectrometer, which, like rare events, is also based on Poissonian statistics. We use the instrument to characterize the slow photochemical degradation kinetics of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) in o-dichlorobenzene. We have employed in situ optical microscopy measurements and electrodynamics simulations to characterize the excitation beam profile inside a liquid-filled capillary fiber. We compare the cuvette and capillary fiber sample holders and show that the MEH-PPV fluorescence line shape is independent of the sample holder, as expected. We characterize the photochemical degradation kinetics of MEH-PPV in o-dichlorobenzene solutions placed in the cuvette versus that in the capillary fiber. We observe small and slow changes in the time-dependent fluorescence spectra when the degradation reaction is performed in the cuvette. On the other hand, we are able to characterize reactant-concentration decay and product-concentration buildup from the time-dependent fluorescence spectra recorded during photochemical degradation of MEH-PPV performed inside the capillary optical fiber. Ultrafast optically heterodyne-detected optical Kerr effect spectroscopy and multimode Brownian oscillator analysis provide further insights into the role of bath oscillator modes of friction in the mechanism of MEH-PPV photochemical degradation. Overall, the work presented herein shows that slow photochemical degradation kinetics of MEH-PPV can be successfully and efficiently assessed in the capillary fiber fluorescence spectrometer.2627192727CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçãoSem informaçãoSem informaçãoWe thank CNPq, SAE-UNICAMP, and FAPESP for undergraduate research fellowships awarded to A.F.C., J.L., and G.A.M. Financial support from CNPq, CAPES, FAPESP, INCT-Cat is gratefully acknowledged. We thank the reviewers for their comments and suggestions

Ultrafast dynamics of au nanopyramid interfaces prepared by nanosphere lithography: effect of substrate chemical composition

This work describes ultrafast spectroscopy studies of Au triangular pyramid particle arrays deposited over glass (termed Au/glass), and 190 nm indium tin oxide (ITO) film (termed Au/ITO/glass) prepared by nanosphere lithography. The linear absorption spectra of Au/glass and Au/ITO/glass exhibit surface plasmon resonances at 800 and 870 nm, respectively, in good agreement with discrete dipole approximation simulations. Ultrafast pump-probe measurements at wavelengths below resonance, at resonance, and above the surface plasmon resonance for each of these two systems are presented. The pump-probe measurements on both systems can be well fit with a model accounting for electron-electron scattering, electron-phonon coupling, and acoustic oscillations on top of cooling of the gold lattice. Numerical simulations employing a two-temperature model are consistent with the single-color pump-probe exponential decays. The wavelength-dependent pump-probe results are interpreted in terms of the complex wavelength-dependent refractive index of gold. We show that this interpretation is consistent with diffractive-optic four-wave mixing spectroscopy measurements of absorptive and dispersive parts of the third-order nonlinear polarization at 800 nm272423433FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçã

“On the fly” characterization of YbIII:ErIII co-doped upconversion nanoparticle nonlinear optical response from single-particle trajectories

Spectroscopic characterization of individual nanoparticles is essential for understanding their structure-property relationship and for applications. Upconversion nanoparticles (UCNPs) in condensed phases can undergo both nonlinear optical and stochastic dynamics when interacting with near-infrared sources. By integrating optical trapping microspectroscopy, stochastic dynamics and light-matter interactions experiments and simulations, in the present work we study how individual trajectories of YbIII:ErIII co-doped UCNPs can be used to perform “on the fly” characterization of their nonlinear optical power-law response upon near-infrared excitation. We illustrate the methodology in the case of freely diffusing and optically trapped UCNPs as well as with particles bound to the substrate. The approach presented in this work can be applied to UCNPs with varying composition and morphological features, particularly in single-particle studies.Fil: Cavalcante, Isabela N.. Universidade Estadual de Campinas; BrasilFil: Marchi, María Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Microscopías Avanzadas; ArgentinaFil: Sigoli, Fernando A.. Universidade Estadual de Campinas; BrasilFil: de Sousa Filho, Paulo C.. Universidade Estadual de Campinas; BrasilFil: Barja, Beatriz Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Nome, René A.. Universidade Estadual de Campinas; Brasi

Costituzione francese del 1791 Napoli : dai torchi del Giornale Costituzionale : si vende da Marotta e Vanspandoch, piazza S. Domenico n. 13 : da Borrelli strada Trinità Maggiore num. 6 : nel Gabinetto Letterario, Largo Trinità Maggiore : da Girard, strada Toledo, num. 165, 1820 Nome del traduttore, Angelo Lanzellotti, a c. a c.

Costituzione francese del 1791 Napoli : dai torchi del Giornale Costituzionale : si vende da Marotta e Vanspandoch, piazza S. Domenico n. 13 : da Borrelli strada Trinità Maggiore num. 6 : nel Gabinetto Letterario, Largo Trinità Maggiore : da Girard, strada Toledo, num. 165, 1820 Nome del traduttore, Angelo Lanzellotti, a c. a c. Sul front. l'indicazione di distribuzione precede il nome dell'editor

Management del paziente con cefalea, vertigine e sincope: dalle evidenze alla pratica clinica

Approccio clinico alle cefalee: dalle evidenze alla pratica clinica P. Gnerre, O. Para, F. De Antoniis, D. Cavalieri, M. Piombo Approccio al paziente con vertigine P. Gnerre, C. Casati, M. Frualdo, M. Cavalleri, S. Guizzetti Management del paziente con sincope: razionale e obiettivi T.M. Attardo, E. Magnani, N. Artom, S. Barco, N. Battino, D. Cervo, M. Chiuch, M. Frualdo, M. Gino, F. Pasin, C. Zaninett

Management del paziente con diarrea, nausea e vomito, malnutrizione e malattia celiaca: lo stato dell'arte

MANAGEMENT DEL PAZIENTE CON DIARREA, NAUSEA E VOMITO: DALLE EVIDENZE ALLA PRATICA CLINICA La gestione del paziente con diarrea: razionale e obiettivi T.M. Attardo, C. Quarneti, R. Menichella, E. Romualdi La gestione del paziente con nausea e vomito: razionale e obiettivi T.M. Attardo, R. Menichella, C. Quarneti, E. Romualdi MALNUTRIZIONE E MALATTIA CELIACA: LO STATO DELL’ARTE La gestione del paziente con malnutrizione: dalle evidenze alla pratica clinica S. Ciarla, M. Poggiano, P. Gnerre, F. Risaliti, L. Magni, L. Morbidoni, A. Maffettone, A. Paradiso, M. Rondana, A. Schimizzi, R. Risicato La gestione del paziente con malattia celiaca: razionale e obiettivi T.M. Attardo, E. Magnani, C. Casati, D. Cavalieri, P. Crispino, F. Fascì Spurio, S. De Carli, D. Tirotta, P. Gnerr

CRABP1, C1QL1 and LCN2 are biomarkers of differentiated thyroid carcinoma, and predict extrathyroidal extension

The prognostic variability of thyroid carcinomas has led to the search for accurate biomarkers at the molecular level. Follicular thyroid carcinoma (FTC) is a typical example of differentiated thyroid carcinomas (DTC) in which challenges are faced in the differential diagnosis. Methods: We used high-throughput paired-end RNA sequencing technology to study four cases of FTC with different degree of capsular invasion: two minimally invasive (mFTC) and two widely invasive FTC (wFTC). We searched by genes differentially expressed between mFTC and wFTC, in an attempt to find biomarkers of thyroid cancer diagnosis and/or progression. Selected biomarkers were validated by real-time quantitative PCR in 137 frozen thyroid samples and in an independent dataset (TCGA), evaluating the diagnostic and the prognostic performance of the candidate biomarkers. Results: We identified 17 genes significantly differentially expressed between mFTC and wFTC. C1QL1, LCN2, CRABP1 and CILP were differentially expressed in DTC in comparison with normal thyroid tissues. LCN2 and CRABP1 were also differentially expressed in DTC when compared with follicular thyroid adenoma. Additionally, overexpression of LCN2 and C1QL1 were found to be independent predictors of extrathyroidal extension in DTC. Conclusions: We conclude that the underexpression of CRABP1 and the overexpression of LCN2 may be useful diagnostic biomarkers in thyroid tumours with questionable malignity, and the overexpression of LCN2 and C1QL1 may be useful for prognostic purposes.This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia e Inovação in the framework of the project "Institute for Research and Innovation in Health Sciences" (POCI-01-0145-FEDER-007274). Further funding from the project "Advancing cancer research: from basic knowledgment to application";NORTE-01-0145-FEDER-000029; “Projetos Estruturados de I&D&I”, funded by Norte 2020 – Programa Operacional Regional do Norte; The study was funded by grants from the Research Council of Norway through its Centers of Excellence funding scheme (project number 179571). The funding organizations do not have any interference in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript