Abstract: An apparatus for performing photochemical measurements on a liquid or liquid-containing sample includes a light generating system, an optical system configured for directing light from the light generating system towards the sample and a sensing system for measuring at least one optical property of the sample, wherein the light generating system is configured for generating light with intensity levels adjustable within a range, spanning at least three and preferably at least five orders of magnitude; and in that the optical system is configured for directing light from the light generating system towards the sample so as to generate a substantially uniform light intensity level, within a cylindrical region of the sample having a height larger than or equal to five time its radius.

Abstract: A method for detecting a reversibly photoswitchable chemical species in a sample, includes the steps of: a) illuminating the sample with light suitable to be absorbed by the chemical species triggering a reaction affecting an optical property of the chemical species, the first light being periodically-modulated at a fundamental modulation frequency; b) measuring the evolution of the optical property; c) extracting at least one of an in-phase component at a frequency which is an even multiple of the fundamental modulation frequency; and a quadrature component at a frequency which is an odd multiple of the fundamental modulation frequency of a signal representing the evolution; and d) using the extracted component or components for detecting the chemical species. An apparatus for carrying out the method is also provided.

Abstract: A method for detecting a photochemically active chemical species in a sample, comprising the steps of: a) illuminating the sample with light at a wavelength suitable to trigger a reaction affecting an optical property of the chemical species according to an illumination sequence, such that: in at least a first time window, the kinetics of the first reaction is limited by a photochemically-activated step of the reaction; and in at least a second time window, the kinetics of the first reaction is limited by a thermally-activated step; b) measuring the evolution of the optical property during the first and the second time windows; c) determining at least a first and a second time constant representing the kinetics of the first reaction in the first and the second time windows, respectively; and d) using the determined time constants for identifying the chemical species. An apparatus for carrying out such a method.

Abstract: Fluorescent labeling of proteins. In particular, membrane-impermeant fluorogenic chromophores being capable of binding reversibly a functional derivative of a Photoactive Yellow Protein (PYP), or a functional fragment thereof, for fluorescently labeling biological molecules of interest, preferably proteins of interest. Especially, 4-hydroxybenzylidene-rhodanine (HBR) analogs of formula (II) as membrane-impermeant fluorogenic chromophores.

Abstract: A method is provided for detecting a fluorescent species that is reversibly photoswitchable at high frequency, and more precisely to a method for detecting at least one reversibly photoswitchable fluorescent species, including a step consisting in illuminating a sample containing a reversibly photoswitchable fluorescent species with a first illuminating light beam, of wavelength ?1, and periodically modulated at an angular frequency ?, and with a second illuminating light beam of wavelength ?2 different from ?1, which is periodically modulated at the angular frequency ?, the second illuminating light beam being modulated in antiphase with respect to the first illuminating light beam.

Abstract: Fluorescent labeling of proteins. In particular, membrane-impermeant fluorogenic chromophores being capable of binding reversibly a functional derivative of a Photoactive Yellow Protein (PYP), or a functional fragment thereof, for fluorescently labeling biological molecules of interest, preferably proteins of interest. Especially, 4-hydroxybenzylidene-rhodanine (HBR) analogs of formula (II) as membrane-impermeant fluorogenic chromophores.

Abstract: A method is provided for detecting a fluorescent species that is reversibly photoswitchable at high frequency, and more precisely to a method for detecting at least one reversibly photoswitchable fluorescent species, including a step consisting in illuminating a sample containing a reversibly photoswitchable fluorescent species with a first illuminating light beam, of wavelength ?1, and periodically modulated at an angular frequency ?, and with a second illuminating light beam of wavelength ?2 different from ?1, which is periodically modulated at the angular frequency ?, the second illuminating light beam being modulated in antiphase with respect to the first illuminating light beam.

Abstract: A method for detection of at least one reversibly photo-convertible fluorescent species, comprises the following steps: a) illumination of a sample comprising said or at least one of the reversibly photo-convertible fluorescent species by a periodically modulated illuminating light; and b) detection of fluorescent emission emitted by the sample thus illuminated; wherein the method further comprises the following step: c) extraction of the amplitude of the intensity component of the fluorescent emission exhibiting the same periodicity as the periodically modulated illuminating light and a phase quadrature with respect to the same; and wherein the mean intensity of the illuminating light and the modulation frequency of the same are chosen to maximize the amplitude of the intensity component of the fluorescent emission.

Abstract: Disclosed is a functional derivative of a Photoactive Yellow Protein (PYP), or a functional fragment thereof, for fluorescently labelling particles, e.g. proteins, or surfaces, which is capable of binding reversibly a fluorogenic chromophore of formula (I), and which is capable of enhancing the brightness of the fluorogenic chromophore upon complexation thereto; and of inducing the spectral shift of the fluorogenic chromophore through the ionization of an auxochromic group thereof.

Abstract: Disclosed is a functional derivative of a Photoactive Yellow Protein (PYP), or a functional fragment thereof, for fluorescently labelling particles, e.g. proteins, or surfaces, which is capable of binding reversibly a fluorogenic chromophore of formula (I), and which is capable of enhancing the brightness of the fluorogenic chromophore upon complexation thereto; and of inducing the spectral shift of the fluorogenic chromophore through the ionization of an auxochromic group thereof.

Abstract: Method for detection of at least one reversibly photo-convertible fluorescent species (P), comprising the following steps: a) illumination of a sample comprising said or at least one of said reversibly photo-convertible fluorescent species by a periodically modulated illuminating light (FEX); and b) detection of fluorescent emission (FLU) emitted by the sample thus illuminated; characterized in that the method further comprises the following step: c) extraction of the amplitude (IFOUt) of the intensity component of said fluorescent emission exhibiting the same periodicity as said periodically modulated illuminating light and a phase quadrature with respect to the same; and in that the mean intensity of said illuminating light and the modulation frequency of the same are chosen in such a way as to maximise said amplitude of the intensity component of said fluorescent emission.

Abstract: The method according to the invention includes choosing a reaction presumed reaction mechanism; selecting, for said mechanism, at least one first function characteristic of a thermokinetic property that is invariant with the periodic variation frequency of a control parameter influencing said reaction, the first characteristic function being calculated at least from first-order oscillation amplitudes of the concentration of at least one of the species involved in said reaction. The method includes calculating a plurality of values of the first characteristic function from first-order oscillation amplitudes obtained experimentally and analyzing the calculated values of the first characteristic function to determine whether the first characteristic function is constant based on the calculated values, and if the first characteristic function is constant, assigning the presumed mechanism to said reaction.

Abstract: A method for separating a chemical or biological compound present in a mixture of similar compounds by diffusion in a medium, the method comprising reacting the compounds of the mixture with a component (P) present in the medium to obtain products (Qi), wherein the reactions Ci+P?Qi are reversible and have kinetic constants k1 and k2, and applying to the medium a varying field to which the compounds are sensitive, wherein the period of the field and the concentration of component (P) in the medium are determined from the kinetic constants (k1,k2) of the compound (C) to be separated in order to establish resonance condition between said reactions and the field and for giving compound C an apparent diffusion coefficient (Da) in the medium that is maximum.

Abstract: A method for separating a chemical or biological compound present in a mixture of similar compounds by diffusion in a medium, the method comprising (i) introducing a mixture of compounds into said medium (ii) reacting the compounds (Ci) of the mixture in the medium with a component (P) present in the medium to obtain products (Qi), wherein the reactions Ci+P→Qi are reversible and have kinetic constants k1,I in the direction of production of products (Qi) and (k2,i) in the reverse direction; and (iii) applying to the medium a field that varies periodically with time and to which compounds (Ci) are sensitive, wherein the period of the field and the concentration of component (P) in the medium are determined as a function of the kinetic constants (k1,k2) of the compound (C) to be separated to establish resonance condition between said reactions and the field, for which compound C has an apparent diffusion coefficient (Da) in the medium that is a maximum value.