scholarly journals The Dissipative Photochemical Origin of Life: UVC Abiogenesis of Adenine

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 217
Author(s):  
Karo Michaelian
Keyword(s):  
Origin Of Life ◽  
Kinetic Equations ◽  
Irreversible Thermodynamic ◽  
Photochemical Reactions ◽  
Photon Flux ◽  
Absorption Bands ◽  
Water Solvent ◽  
Wavelength Absorption ◽  
Far From Equilibrium ◽  
Selection Of

The non-equilibrium thermodynamics and the photochemical reaction mechanisms are described which may have been involved in the dissipative structuring, proliferation and complexation of the fundamental molecules of life from simpler and more common precursors under the UVC photon flux prevalent at the Earth’s surface at the origin of life. Dissipative structuring of the fundamental molecules is evidenced by their strong and broad wavelength absorption bands in the UVC and rapid radiationless deexcitation. Proliferation arises from the auto- and cross-catalytic nature of the intermediate products. Inherent non-linearity gives rise to numerous stationary states permitting the system to evolve, on amplification of a fluctuation, towards concentration profiles providing generally greater photon dissipation through a thermodynamic selection of dissipative efficacy. An example is given of photochemical dissipative abiogenesis of adenine from the precursor HCN in water solvent within a fatty acid vesicle floating on a hot ocean surface and driven far from equilibrium by the incident UVC light. The kinetic equations for the photochemical reactions with diffusion are resolved under different environmental conditions and the results analyzed within the framework of non-linear Classical Irreversible Thermodynamic theory.

scholarly journals The Dissipative Photochemical Origin of Life: UVC Abiogenesis of Adenine

2021 ◽  
Author(s):  
Karo Michaelian
Keyword(s):  
Origin Of Life ◽  
Kinetic Equations ◽  
Reaction Rates ◽  
Photon Flux ◽  
Common Precursor ◽  
Wavelength Absorption ◽  
The Common ◽  
The Origin Of Life ◽  
Precursor Molecules ◽  
Non Equilibrium

I describe the non-equilibrium thermodynamics and the photochemical mechanisms which may have been involved in the dissipative synthesis, proliferation, and evolution of the fundamental molecules at the origin of life from simpler and more common precursor molecules such as HCN, H2O and CO2 under the impressed UVC photon flux of the Archean. The fundamental molecules absorb strongly in this UVC region and exhibit strong coupling between their electronic excited and ground states which endows them with efficient photon disipative capacity (broad wavelength absorption and rapid radiationless dexcitation) suggestive of dissipative structuring. The autocatalytic nature of the synthesized molecules in dissipating the same photochemical potential that directed their synthesis leads to their proliferation. The non-linearity in the photochemical and chemical reaction rates provides numerous stationary states which can be reached by amplification of a molecular concentration fluctuation near a bifurcation, promoting the system into states of generally higher photon disspative efficacy. An example is given of the UV photochemical dissipative structuring, proliferation, and evolution of molecules on route to the nucleobase adenine from the common precursor molecules HCN and H2O occurring within a fatty acid vesicle. The kinetic equations are resolved under different environmental conditions, providing a non-equilibrium thermodynamic analysis of the appearance of an early important molecule for the origin of life.

scholarly journals Photochemical Dissipative Structuring of the Fundamental Molecules of Life

Proceedings ◽  
2019 ◽  
Vol 46 (1) ◽  
pp. 20
Author(s):  
Karo Michaelian
Keyword(s):  
Nonequilibrium Thermodynamics ◽  
Irreversible Thermodynamic ◽  
Stationary States ◽  
Long Wavelength ◽  
Common Precursor ◽  
Molecular Concentration ◽  
Wavelength Absorption ◽  
Nonequilibrium Conditions ◽  
Precursor Molecules ◽  
Selection Of

It has been conjectured that the origin of the fundamental molecules of life, their proliferation over the surface of Earth, and their complexation through time, are examples of photochemical dissipative structuring, dissipative proliferation, and dissipative selection, respectively, arising out of the nonequilibrium conditions created on Earth’s surface by the solar photon spectrum. Here I describe the nonequilibrium thermodynamics and the photochemical mechanisms involved in the synthesis and evolution of the fundamental molecules of life from simpler more common precursor molecules under the long wavelength UVC and UVB solar photons prevailing at Earth’s surface during the Archean. Dissipative structuring through photochemical mechanisms leads to carbon based UVC pigments with peaked conical intersections which endow them with a large photon disipative capacity (broad wavelength absorption and rapid radiationless dexcitation). Dissipative proliferation occurs when the photochemical dissipative structuring becomes autocatalytic. Dissipative selection arises when fluctuations lead the system to new stationary states (corresponding to different molecular concentration profiles) of greater dissipative capacity as predicted by the universal evolution criterion of Classical Irreversible Thermodynamic theory established by Onsager, Glansdorff, and Prigogine. An example of the UV photochemical dissipative structuring, proliferation, and selection of the nucleobase adenine from an aqueous solution of HCN under UVC light is given.

Photocytotoxicity of Anthracyclines upon Laser Excitation in Their Long-Wavelength Absorption Bands

1991 ◽  
Vol 127 (1) ◽  
pp. 24 ◽  
Author(s):  
Alessandra Andreoni ◽  
Alberto Colasanti ◽  
Vincenzo Malatesta ◽  
Giuseppe Roberti
Keyword(s):  
Laser Excitation ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Wavelength Absorption

scholarly journals Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: sparse methods for statistical selection of relevant absorption bands

2016 ◽  
Vol 9 (7) ◽  
pp. 3429-3454 ◽  
Author(s):  
Satoshi Takahama ◽  
Giulia Ruggeri ◽  
Ann M. Dillner
Keyword(s):  
Infrared Spectra ◽  
Atmospheric Aerosols ◽  
Quantitative Prediction ◽  
Calibration Model ◽  
Vibrational Modes ◽  
Aerosol Composition ◽  
Absorption Bands ◽  
Calibration Models ◽  
Ft Ir ◽  
Selection Of

Abstract. Various vibrational modes present in molecular mixtures of laboratory and atmospheric aerosols give rise to complex Fourier transform infrared (FT-IR) absorption spectra. Such spectra can be chemically informative, but they often require sophisticated algorithms for quantitative characterization of aerosol composition. Naïve statistical calibration models developed for quantification employ the full suite of wavenumbers available from a set of spectra, leading to loss of mechanistic interpretation between chemical composition and the resulting changes in absorption patterns that underpin their predictive capability. Using sparse representations of the same set of spectra, alternative calibration models can be built in which only a select group of absorption bands are used to make quantitative prediction of various aerosol properties. Such models are desirable as they allow us to relate predicted properties to their underlying molecular structure. In this work, we present an evaluation of four algorithms for achieving sparsity in FT-IR spectroscopy calibration models. Sparse calibration models exclude unnecessary wavenumbers from infrared spectra during the model building process, permitting identification and evaluation of the most relevant vibrational modes of molecules in complex aerosol mixtures required to make quantitative predictions of various measures of aerosol composition. We study two types of models: one which predicts alcohol COH, carboxylic COH, alkane CH, and carbonyl CO functional group (FG) abundances in ambient samples based on laboratory calibration standards and another which predicts thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) mass in new ambient samples by direct calibration of infrared spectra to a set of ambient samples reserved for calibration. We describe the development and selection of each calibration model and evaluate the effect of sparsity on prediction performance. Finally, we ascribe interpretation to absorption bands used in quantitative prediction of FGs and TOR OC and EC concentrations.

Synthesis and spectroscopic properties of benzo- and naphthofuryl-3-hydroxychromones

2001 ◽  
Vol 79 (4) ◽  
pp. 358-363 ◽  
Author(s):  
Andrey S Klymchenko ◽  
Turan Ozturk ◽  
Vasyl G Pivovarenko ◽  
Alexander P Demchenko
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Spectroscopic Properties ◽  
Molecular Probe ◽  
Absorption Bands ◽  
Methyl Group ◽  
Long Wavelength ◽  
Excited State Proton Transfer ◽  
Wavelength Absorption ◽  
Long Wavelength Absorption Band

With the focus of designing new fluorescent probes, four new 3-hydroxy-chromone derivatives bearing benzofuran and naphthofuran groups were synthesized. They show bathochromic absorption shifts relative to 3-hydroxyflavone with the ability of retention to display the excited-state proton transfer. Disruption of the planarity by the methyl group in the furan ring leads to a decrease of both the extinction coefficient and the contribution of long wavelength absorption band, while molecules without a methyl group showed two distinct absorption bands. Shifts to longer wavelengths are also observed in fluorescent spectra, and the absence of the methyl group results in a dramatic increase of fluorescence quantum yield and lifetime. Of the extended 3-hydroxychromone derivatives, 3-hydroxy-2-naphtho[2,1-b]furan-2-yl-chromone has shown comparable, and in some cases better, absorption and fluorescence properties than the 3-hydroxychromones synthesized so far, which make it a highly promising candidate as molecular probe for analytical chemistry, biophysics, and cellular biology.Key words: benzo- and naphthofuryl-3-hydroxyflavone, synthesis, electronic spectra, fluorescence, excited state proton transfer.

scholarly journals Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

2017 ◽  
Vol 13 ◽  
pp. 2902-2914 ◽  
Author(s):  
Aleksey A Vasilev ◽  
Meglena I Kandinska ◽  
Stanimir S Stoyanov ◽  
Stanislava B Yordanova ◽  
David Sucunza ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Cationic Dyes ◽  
Thiazole Orange ◽  
Absorption Bands ◽  
Tddft Calculations ◽  
Absorption And Fluorescence Spectroscopy ◽  
Synthetic Procedure ◽  
Wavelength Absorption ◽  
Derivatives Of ◽  
Dft And Tddft Calculations

Novel asymmetric monomeric monomethine cyanine dyes 5a–d, which are analogues of the commercial dsDNA fluorescence binder thiazole orange (TO), have been synthesized. The synthesis was achieved by using a simple, efficient and environmetally benign synthetic procedure to obtain these cationic dyes in good to excellent yields. Interactions of the new derivatives of TO with dsDNA have been investigated by absorption and fluorescence spectroscopy. The longest wavelength absorption bands in the UV–vis spectra of the target compounds are in the range of 509–519 nm and these are characterized by high molar absorptivities (63000–91480 L·mol−1·cm−1). All investigated dyes from the series are either not fluorescent or their fluorescence is quite low, but they become strongly fluorescent after binding to dsDNA. The influence of the substituents attached to the chromophores was investigated by combination of spectroscopic (UV–vis and fluorescence spectroscopy) and theoretical (DFT and TDDFT calculations) methods.

scholarly journals An X-ray harmonic separator for next-generation synchrotron X-ray sources and X-ray free-electron lasers

2018 ◽  
Vol 25 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Ichiro Inoue ◽  
Taito Osaka ◽  
Kenji Tamasaku ◽  
Haruhiko Ohashi ◽  
Hiroshi Yamazaki ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Grazing Incidence ◽  
Incidence Geometry ◽  
Photon Flux ◽  
Free Electron Lasers ◽  
Undulator Radiation ◽  
X Ray ◽  
Grazing Incidence Geometry ◽  
Selection Of

An X-ray prism for the extraction of a specific harmonic of undulator radiation is proposed. By using the prism in a grazing incidence geometry, the beam axes of fundamental and harmonics of undulator radiation are separated with large angles over 10 µrad, which enables the selection of a specific harmonic with the help of apertures, while keeping a high photon flux. The concept of the harmonic separation was experimentally confirmed using X-ray beams from the X-ray free-electron laser SACLA.

scholarly journals Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: sparse methods for statistical selection of relevant absorption bands

2016 ◽  
Author(s):  
Satoshi Takahama ◽  
Giulia Ruggeri ◽  
Ann M. Dillner
Keyword(s):  
Infrared Spectroscopy ◽  
Infrared Spectra ◽  
Atmospheric Aerosols ◽  
Model Building ◽  
Quantitative Prediction ◽  
Calibration Model ◽  
Aerosol Composition ◽  
Absorption Bands ◽  
Calibration Models ◽  
Selection Of

Abstract. We present an evaluation of four algorithms for achieving sparsity in Fourier Transform Infrared Spectroscopy calibration models. Sparse calibration models exclude unnecessary wavenumbers from infrared spectra during the model building process, permitting identification and evaluation of the most relevant vibrational modes of molecules in complex aerosol mixtures required to make quantitative predictions of various measures of aerosol composition. We study two types of models: one which predicts alcohol COH, carboxylic COH, alkane CH, and carbonyl CO functional group (FG) abundances in ambient samples based on laboratory calibration standards, and another which predicts thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) mass in new ambient samples by direct calibration of infrared spectra to a set of ambient samples reserved for calibration. We describe the development and selection of each calibration model, and evaluate the effect of sparsity on prediction performance. Finally, we ascribe interpretation to absorption bands used in quantitative prediction of FGs and TOR OC and EC concentrations.

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