Organic synthesis from reducing models of the atmosphere of the primitive earth with UV light and electric discharges

1982 ◽  
Vol 18 (3) ◽  
pp. 173-178 ◽  
Author(s):  
Alain R. Bossard ◽  
François Raulin ◽  
Didier Mourey ◽  
Gérard Toupance
Keyword(s):  
Organic Synthesis ◽  
Uv Light ◽  
Electric Discharges ◽  
Primitive Earth

UV-Light-Induced Dehydrogenative N-Acylation of Amines with 2-Nitrobenzaldehydes to Give 2-Aminobenzamides

Synthesis ◽  
2022 ◽  
Author(s):  
Dishu Zeng ◽  
Tianbao Yang ◽  
Niu Tang ◽  
Wei Deng ◽  
Jiannan Xiang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Organic Synthesis ◽  
Efficient Method ◽  
Building Block ◽  
Room Temperature ◽  
Uv Light ◽  
Amino Acid Derivatives ◽  
One Pot ◽  
Plausible Mechanism ◽  
High Yields

A simple, mild, green and efficient method for the synthesis of 2-aminobenzamides was highly desired in organic synthesis. Herein, we developed an efficient, one-pot strategy for the synthesis of 2-aminobenzamides with high yields irradiated by UV light. 32 examples proceeded successfully by this photo-induced protocol. The yield reached up to 92%. The gram scale was also achieved easily. This building block could be applied in the preparation of quinazolinones derivatives. Amino acid derivatives could be employed smoothly at room temperature. Finally, a plausible mechanism was proposed.

scholarly journals Organic-Photoacid-Catalyzed Glycosylation

Synlett ◽  
2020 ◽  
Vol 31 (09) ◽  
pp. 823-828
Author(s):  
Ting Wang ◽  
Juncheng Li ◽  
Gaoyuan Zhao
Keyword(s):  
Photodynamic Therapy ◽  
Visible Light ◽  
Organic Synthesis ◽  
Uv Light ◽  
Molecular Switching ◽  
Absorption Of Light

Photoacids are molecules that become more acidic upon absorption of light. They are widely utilized in a variety of fields, such as organic synthesis, molecular switching agents, and photodynamic therapy. Currently, the activity of most photoacids is induced by UV light, which limits their applications by the synthetic community. In this ­Synpacts article, we highlight our recent development of visible-light-­induced photoacids and their application in glycosylation reactions.1 Introduction2 Visible-Light-Induced Photoacids3 Synthesis of 2-Deoxyglycosides by Visible-Light-Induced Photoacid Catalysis4 Conclusion

Streamer discharges in the atmosphere of Primordial Earth

2020 ◽  
Author(s):  
Martin Bødker Enghoff ◽  
Nikolaos Segkos ◽  
Sasa Dujko ◽  
Olivier Chanrion ◽  
Christoph Köhn
Keyword(s):  
Electric Fields ◽  
Electric Discharges ◽  
Monte Carlo Code ◽  
Primitive Earth ◽  
Particle In Cell ◽  
Early Atmosphere ◽  
Photoionization Process ◽  
Electron Avalanches ◽  
Life On Earth ◽  
Primordial Earth

<p>Motivated by the Miller-Urey experiment suggesting that lightning may have contributed to the origin of life on Earth through the formation of amino acids and carbonic acids, we here investigate the occurrence of electric discharges in the atmosphere of Primordial Earth. We focus on the early stages of lightning in the atmosphere of Primordial Earth, the so-called streamers, thin ionized plasma channels.</p><p>We study electron avalanches and potential avalanche-to-streamer transitions by modeling the motion of electrons with a particle-in-cell Monte Carlo code in gas mixtures of H<sub>2</sub>O:CH<sub>4</sub>:NH<sub>3</sub>:H<sub>2</sub>=37.5%:25%:25%:12.5% [S. L. Miller. Production of Some Organic Compounds under Possible Primitive Earth Conditions. Am. Chem. Soc., 77:9, pp. 2351-2361 (1955)] and N<sub>2</sub>:CO<sub>2</sub>:H<sub>2</sub>O:H<sub>2</sub>:CO=80%:18.89%:1%:0.1%:0.01% [J. F. Kasting. Earth’s Early Atmosphere. Science, 259:5097, pp. 920-926 (1993)] suggested for Primordial Earth approx. 3.8 Ga ago in different electric fields and for different levels of background ionization mimicking the photoionization process. We compare the evolution of the electron density,  electric field, and electron energies with those for Modern Earth. Finally, we will discuss which conditions favour streamer inception, as well as consequences for discharges on Primordial Earth.</p>

A protective function of the coacervates against UV light on the primitive Earth

Nature ◽  
1982 ◽  
Vol 299 (5881) ◽  
pp. 347-349 ◽  
Author(s):  
Hiroyuki Okihana ◽  
Cyril Ponnamperuma
Keyword(s):  
Uv Light ◽  
Primitive Earth ◽  
Protective Function

scholarly journals Visible-Light Photocatalysts and Their Perspectives for Building Photocatalytic Membrane Reactors for Various Liquid Phase Chemical Conversions

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1334
Author(s):  
Raffaele Molinari ◽  
Cristina Lavorato ◽  
Pietro Argurio
Keyword(s):  
Water Treatment ◽  
Visible Light ◽  
Organic Synthesis ◽  
Uv Light ◽  
Nitro Compounds ◽  
Green Technology ◽  
Membrane Reactors ◽  
Chemical Transformations ◽  
Uv Light Irradiation ◽  
Phase Chemical

Photocatalytic organic synthesis/conversions and water treatment under visible light are a challenging task to use renewable energy in chemical transformations. In this review a brief overview on the mainly employed visible light photocatalysts and a discussion on the problems and advantages of Vis-light versus UV-light irradiation is reported. Visible light photocatalysts in the photocatalytic conversion of CO2, conversion of acetophenone to phenylethanol, hydrogenation of nitro compounds, oxidation of cyclohexane, synthesis of vanillin and phenol, as well as hydrogen production and water treatment are discussed. Some applications of these photocatalysts in photocatalytic membrane reactors (PMRs) for carrying out organic synthesis, conversion and/or degradation of organic pollutants are reported. The described cases show that PMRs represent a promising green technology that could shift on applications of industrial interest using visible light (from Sun) active photocatalysts.

Electron microscopy of keratinocytes cultured on a collagen substrate used as an allograft for the treatment of chronic wounds

1992 ◽  
Vol 50 (2) ◽  
pp. 1104-1105
Author(s):  
Debby A. Jennings ◽  
Michael J. Morykwas ◽  
Louis C. Argenta
Keyword(s):  
Electron Microscopy ◽  
Cell Suspension ◽  
Single Cell ◽  
Chronic Wounds ◽  
Mechanical Stability ◽  
Uv Light ◽  
Type I ◽  
Single Cell Suspension ◽  
Collagen Substrate ◽  
Dermal Collagen

Grafts of cultured allogenic or autogenic keratlnocytes have proven to be an effective treatment of chronic wounds and burns. This study utilized a collagen substrate for keratinocyte and fibroblast attachment. The substrate provided mechanical stability and augmented graft manipulation onto the wound bed. Graft integrity was confirmed by light and transmission electron microscopy.Bovine Type I dermal collagen sheets (100 μm thick) were crosslinked with 254 nm UV light (13.5 Joules/cm2) to improve mechanical properties and reduce degradation. A single cell suspension of third passage neonatal foreskin fibroblasts were plated onto the collagen. Five days later, a single cell suspension of first passage neonatal foreskin keratinocytes were plated on the opposite side of the collagen. The grafts were cultured for one month.The grafts were fixed in phosphate buffered 4% formaldehyde/1% glutaraldehyde for 24 hours. Graft pieces were then washed in 0.13 M phosphate buffer, post-fixed in 1% osmium tetroxide, dehydrated, and embedded in Polybed 812.

A photoelectron microscope study of surfaces

1989 ◽  
Vol 47 ◽  
pp. 10-11
Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Field Strength ◽  
Uv Light ◽  
Physical Property ◽  
Photon Flux ◽  
Mercury Lamp ◽  
Object Surface ◽  
The Sixties ◽  
Physical Features

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

Immunolabelling of glomerular deposits in kidney biopsies routinely fixed in glutaraldehyde

1989 ◽  
Vol 47 ◽  
pp. 910-911
Author(s):  
Ś Lhoták ◽  
I. Alexopoulou ◽  
G. T. Simon
Keyword(s):  
Uv Light ◽  
Kidney Diseases ◽  
Light Chains ◽  
Microscopical Level ◽  
Accurate Identification ◽  
Light Microscopical Level ◽  
Dense Deposits ◽  
Cacodylate Buffer ◽  
Glomerular Deposits ◽  
Prognostic Importance

Various kidney diseases are characterized by the presence of dense deposits in the glomeruli. The type(s) of immunoglobulins (Igs) present in the dense deposits are characteristic of the disease. The accurate Identification of the deposits is therefore of utmost diagnostic and prognostic importance. Immunofluorescence (IF) used routinely at the light microscopical level is unable to detect and characterize small deposits found in early stages of glomerulonephritis. Although conventional TEM is able to localize such deposits, it is not capable of determining their nature. It was therefore attempted to immunolabel at EM level IgG, IgA IgM, C3, fibrinogen and kappa and lambda Ig light chains commonly found in glomerular deposits on routinely fixed ( 2% glutaraldehyde (GA) in 0.1M cacodylate buffer) kidney biopsies.The unosmicated tissue was embedded in LR White resin polymerized by UV light at -10°C. A postembedding immunogold technique was employed

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