scholarly journals Radicals in prebiotic chemistry

2020 ◽  
Vol 92 (12) ◽  
pp. 1971-1986 ◽  
Author(s):  
Renee W. J. Lim ◽  
Albert C. Fahrenbach
Keyword(s):  
Prebiotic Chemistry ◽  
Solid Phase ◽  
Dust Particles ◽  
Radical Chemistry ◽  
Interstellar Ice ◽  
Common Thread ◽  
Molecular Synthesis ◽  
Molecular Complexity ◽  
Emergence Of Life ◽  
Synthesis Reactions

AbstractRadical chemistry is tightly interwoven in proposed prebiotic synthetic pathways, reaction networks and geochemical scenarios that have helped shape our understanding of how life could have originated. Gas-phase prebiotic reactions involving electric discharge, vapour ablation by asteroidal and cometary impacts as well as ionising radiation all produce radicals that facilitate complex molecular synthesis. Reactions in the solid phase which are responsible for astrochemical syntheses can also take place through radicals produced via irradiation of protoplanetary/interstellar ice grains and dust particles. Aqueous-phase radical chemistry affords further molecular complexity promoting the production of precursors for the synthesis of biopolymers thought important for the emergence of life. Radical chemistry appears to be a common thread amongst all kinds of prebiotic investigations, and this Review aims to bring attention to a few selected examples. Some important historical studies and modern developments with respect to prebiotic chemistry are summarised through the lens of radical chemistry.

Qualitative assessment of air pollution in the working area of energy-intensive materials production by nanoscale aerosols with a solid dispersed phase

2021 ◽  
Vol 61 (12) ◽  
pp. 828-832
Author(s):  
Boris N. Filatov ◽  
Natalya I. Latyshevskaya ◽  
Natalya V. Krylova ◽  
Irina K. Gorkina ◽  
Yulya I. Velikorodnaya ◽  
...  
Keyword(s):  
Air Pollution ◽  
Mass Concentration ◽  
Solid Phase ◽  
Qualitative Assessment ◽  
Dust Particles ◽  
Dispersed Phase ◽  
Forced Circulation ◽  
Aluminum Powders ◽  
Nanoscale Particles ◽  
Wide Range

The presence of grinding, mixing, and fractionation of solid components of formulations leads to the formation of aerosols in the air of the working area with a wide range of dispersion of the solid phase - all this characterizes the organization of technological processes for the production of energy-intensive materials. The study aims to give a qualitative assessment of possible air pollution of the working area of energy-intensive materials production by nanoscale aerosols with a solid dispersed phase. The researchers carried out the sampling of the working area air and flushes from solid horizontal surfaces to produce energy-intensive materials. We carried out the sampling by forced circulation of the test air through the absorption devices of Polezhaev. Scientists used Triton TX-114 solution with a mass concentration of 2.0 mg/dm3 as an absorption medium. The researchers performed flushing from surfaces using cloth tampons moistened with Triton TX-114 solution with a mass concentration of 2.0 mg/dm3. We determined the particle sizes in the samples using NanotracULTRA (Microtrac). Scientists found aluminum and nitrocellulose particles with sizes from 36 to 102 nm in the air of the working area and flushes from horizontal surfaces. The study of the fractional composition of RDX and aluminum powders of the ASD-1 brand showed the presence of nanoscale particles in them. Nanoscale dust particles pollute the air of the working area and solid horizontal surfaces at certain stages of the production of energy-intensive materials. There are nanoscale particles in the composition of powders of some standard components of formulations. Flushes from solid horizontal surfaces are an adequate qualitative indicator of the presence of nanoaerosols in the air of the working area.

scholarly journals Prebiotic Chemistry — Biochemistry — Emergence of Life (4.4-2 Ga)

2007 ◽  
pp. 153-203 ◽  
Author(s):  
Robert Pascal ◽  
Laurent Boiteau ◽  
Patrick Forterre ◽  
Muriel Gargaud ◽  
Antonio Lazcano ◽  
...  
Keyword(s):  
Prebiotic Chemistry ◽  
Emergence Of Life

Photon and thermal processing of CH3NH2-bearing ices. Synthesis of prebiotic species at low temperature (such as formamide, ethylamine, and methylcyanide), and N-heterocycles during warm up.

2021 ◽  
Author(s):  
Héctor Carrascosa ◽  
Cristóbal González Díaz ◽  
Guillermo M. Muñoz Caro ◽  
Pedro C. Gómez ◽  
María Luz Sanz
Keyword(s):  
Vacuum Chamber ◽  
Organic Molecules ◽  
Solid Phase ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Quadrupole Mass ◽  
Warm Up ◽  
Methyl Cyanide ◽  
Interstellar Ice ◽  
Complex Organic

<p>Hexamethylentetramine has drawn a lot of attention due to its potential to produce prebiotic species. This work aims to gain a better understanding in the chemical processes concerning methylamine under astrophysically relevant conditions. In particular, this work deeps into the formation of N-heterocycles in interstellar ice analogs exposed to UV radiation, which may lead to the formation of prebiotic species.</p> <p>Experimental simulations of interstellar ice analogs were carried out in ISAC. ISAC is an ultra-high vacuum chamber equipped with a cryostat, where gas and vapour species are frozen forming ice samples. Infrared and ultraviolet spectroscopy were used to monitor the solid phase, and quadrupole mass spectrometry served to measure the composition of the gas phase. The variety of species detected after UV irradiation of ices containing  methylamine revealed the presence of 12 species which have been already detected in the ISM, being 4 of them typically classified as complex organic molecules: formamide (HCONH<sub>2</sub>), methyl cyanide (CH<sub>3</sub>CN), CH<sub>3</sub>NH and CH<sub>3</sub>CHNH. Warming up of the irradiated CH<sub>3</sub>NH<sub>2</sub>-bearing ice samples lead to the formation of trimethylentriamine (TMT), a N-heterocycle precursor of HMT, and the subsequent synthesis of HMT at temperatures above 230 K.</p>

The Investigation of a Fluid-Solid Interaction Mathematical Model under Combined Convective Jeffrey Flow and Radiation Effect Embedded Newtonian Heating as the Thermal Boundary Condition over a Vertical Stretching Sheet

2020 ◽  
Vol 399 ◽  
pp. 65-75 ◽  
Author(s):  
Abdul Rahman Mohd Kasim ◽  
Nur Syamilah Arifin ◽  
Syazwani Mohd Zokri ◽  
Mohd Zuki Salleh
Keyword(s):  
Differential Equation ◽  
Boundary Condition ◽  
Stretching Sheet ◽  
Solid Phase ◽  
Particle Interaction ◽  
Thermal Boundary Condition ◽  
Dust Particles ◽  
Jeffrey Fluid ◽  
Physical Parameters ◽  
Newtonian Heating

The investigation on the interaction between solid and fluid under combined convective flow has been carried out mathematically. The Jeffrey fluid model is taken as the fluid phase and the model is being embedded with the dust particles (solid phase). This two-phase model is constructed by introducing the fluid-particles interaction forces in the momentum equations of the fluid and dust phases, respectively. The natural and forced convections together with the aligned magnetic field are considered on the fluid flow. Also, the Newtonian heating as thermal boundary condition is induced on the vertical stretching sheet. In order to reduce the complexity of the model, the governing equations are transformed from partial differential equation into ordinary differential equation via suitable similarity transformation. The solutions are obtained in terms of velocity and temperature profiles for the fluid and particles phases respectively whereby the Keller-box method is utilized to obtain the desired outcomes. The influences of several significant physical parameters are visualized graphically to clarify the flow and heat transfer characteristic for both phases. The investigation found that the fluid’s velocity is affected by the presence of the dust particles which led to decelerate the fluid transference. The present flow model is able to be compared with the single-phase fluid cases if the fluid-particle interaction parameter is ignored.

scholarly journals Formaldehyde and methylamine reactivity in interstellar ice analogues as a source of molecular complexity at low temperature

2012 ◽  
Vol 549 ◽  
pp. A40 ◽  
Author(s):  
V. Vinogradoff ◽  
F. Duvernay ◽  
G. Danger ◽  
P. Theulé ◽  
F. Borget ◽  
...  
Keyword(s):  
Low Temperature ◽  
Interstellar Ice ◽  
Molecular Complexity

scholarly journals Prebiologically Important Interstellar Molecules

2004 ◽  
Vol 213 ◽  
pp. 185-188
Author(s):  
Y.-J. Kuan ◽  
H.-C. Huang ◽  
S. B. Charnley ◽  
W.-L. Tseng ◽  
L. E. Snyder ◽  
...  
Keyword(s):  
Amino Acid ◽  
Organic Molecules ◽  
Prebiotic Chemistry ◽  
Interstellar Space ◽  
Central Question ◽  
Dna And Rna ◽  
The Galaxy ◽  
Molecular Complexity ◽  
Cloud Cores ◽  
Complex Organic

Understanding the organic chemistry of molecular clouds, particularly the formation of biologically important molecules, is fundamental to the study of the processes which lead to the origin, evolution and distribution of life in the Galaxy. Determining the level of molecular complexity attainable in the clouds, and the nature of the complex organic material available to protostellar disks and the planetary systems that form from them, requires an understanding of the possible chemical pathways and is therefore a central question in astrochemistry. We have thus searched for prebiologically important molecules in the hot molecular cloud cores: Sgr B2(N-LMH), W51 e1/e2 and Orion-KL. Among the molecules searched: Pyrimidine is the unsubstituted ring analogue for three of the DNA and RNA bases. 2H-Azirine and Aziridine are azaheterocyclic compounds. And Glycine is the simplest amino acid. Detections of these interstellar organic molecular species will thus have important implications for Astrobiology. Our preliminary results indicate a tentative detection of interstellar glycine. If confirmed, this will be the first detection of an amino acid in interstellar space and will greatly strengthen the thesis that interstellar organic molecules could have played a pivotal role in the prebiotic chemistry of the early Earth.

Study of Sand Particle Trajectories and Erosion Into the First Fan Stage of a Turbofan

2010 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Gas Turbines ◽  
Solid Phase ◽  
Engine Performance ◽  
Suction Side ◽  
Dust Particles ◽  
Sand Particle ◽  
Computational Domain ◽  
Complex Flow ◽  
Particle Trajectories ◽  
Trailing Edges

Ingestion of dust particles by aero-engines or stationary gas turbines is inevitable when operating in extremely polluted environments. The impingements of particles on the surfaces of blades cause erosion damage and permanent losses in engine performance. This paper presents a study of the particle dynamics and erosion in the first stage of a turbofan. The steady flow field through the turbomachinery components was solved separately from the solid phase. The particle trajectories computations used a stochastic Lagrangian tracking code that implements probabilistic modeling for particle size rebound and fragmentation, and considers the eddy-lifetime concept for turbulence and the complex flow features near walls. The equations of a particle motion were solved in a stepwise manner using the seventh order RK-Fehlberg technique, whereas particle tracking in different cells of the computational domain used the finite element method. Computations of particle trajectories were carried out for sand particles MIL-E5007E (0–1000 microns) at low, mid and high concentrations. As the locations of impacts were predicted, erosion contours were estimated and the subsequent blade deteriorations were assessed. The rotor blade shows a noticeable erosion of the blade leading and trailing edges almost from root to tip and a rounding of blade tip. Erosion patterns in the diffuser depict high erosion at blade leading and trailing edges and the erosion of pressure side is spreading almost from root to tip, in addition to erosion over the suction side. The actual findings may serve in improving erosion resistance of the blades in this fan stage.

Thermal reactions in interstellar ice: A step towards molecular complexity in the interstellar medium

2013 ◽  
Vol 52 (8) ◽  
pp. 1567-1579 ◽  
Author(s):  
P. Theulé ◽  
F. Duvernay ◽  
G. Danger ◽  
F. Borget ◽  
J.B. Bossa ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Thermal Reactions ◽  
Interstellar Ice ◽  
Molecular Complexity

scholarly journals Use of Free Radical Chemistry in an Immunometric Assay for 17β-Estradiol

2001 ◽  
Vol 47 (1) ◽  
pp. 102-109 ◽  
Author(s):  
Laure Buscarlet ◽  
Hervé Volland ◽  
Jacqueline Dupret-Carruel ◽  
Michel Jolivet ◽  
Jacques Grassi ◽  
...  
Keyword(s):  
Free Radical ◽  
Human Serum ◽  
Solid Phase ◽  
Regression Line ◽  
Cross Reactivity ◽  
Radical Chemistry ◽  
Immunometric Assay ◽  
Human Sera ◽  
17Β Estradiol ◽  
Free Radical Chemistry

Abstract Background: We wished to develop an enzyme immunometric assay for 17β-estradiol (E2) in human serum using solid-phase immobilized epitope immunoassay (SPIE-IA) technology and free radical chemistry. Methods: We used an anti-estradiol monoclonal antibody as capture antibody and Fenton-like reagents to cross-link it to E2. The same antibody, labeled with acetylcholinesterase, was used for detection. Serum was diluted 10-fold before assay. Results: After correction by the dilution factor, the detection limit was 5 ng/L for human serum and intra- and interassay CVs were <7% and 15%, respectively, at concentrations of 169-2845 ng/L. No cross-reactivity was seen with other natural steroids. In comparison with a competitive commercial RIA performed on 88 undiluted human sera, the slope (SD) of the regression line was 1.05 (± 0.02) and the intercept was 47 (±27) ng/L (Sy|x = 186 ng/L) at concentrations of 20–5000 ng/L (r2 = 0.97). Conclusions: The use of Fenton-like chemistry in SPIE-IA technology allows a sensitive measurement of E2 in human serum and could be a new approach for the development of sensitive immunoassays.

scholarly journals Solid State Pathways towards Molecular Complexity in Space

2011 ◽  
Vol 7 (S280) ◽  
pp. 390-404 ◽  
Author(s):  
Harold Linnartz ◽  
Jean-Baptiste Bossa ◽  
Jordy Bouwman ◽  
Herma M. Cuppen ◽  
Steven H. Cuylle ◽  
...  
Keyword(s):  
Solid State ◽  
Interstellar Medium ◽  
Vacuum Ultraviolet ◽  
Cosmic Ray ◽  
Solid State Reactions ◽  
Thermal Heating ◽  
Interstellar Ice ◽  
Molecular Complexity ◽  
Physical And Chemical ◽  
Complex Organic

AbstractIt has been a long standing problem in astrochemistry to explain how molecules can form in a highly dilute environment such as the interstellar medium. In the last decennium more and more evidence has been found that the observed mix of small and complex, stable and highly transient species in space is the cumulative result of gas phase and solid state reactions as well as gas-grain interactions. Solid state reactions on icy dust grains are specifically found to play an important role in the formation of the more complex “organic” compounds. In order to investigate the underlying physical and chemical processes detailed laboratory based experiments are needed that simulate surface reactions triggered by processes as different as thermal heating, photon (UV) irradiation and particle (atom, cosmic ray, electron) bombardment of interstellar ice analogues. Here, some of the latest research performed in the Sackler Laboratory for Astrophysics in Leiden, the Netherlands is reviewed. The focus is on hydrogenation, i.e., H-atom addition reactions and vacuum ultraviolet irradiation of interstellar ice analogues at astronomically relevant temperatures. It is shown that solid state processes are crucial in the chemical evolution of the interstellar medium, providing pathways towards molecular complexity in space.

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