Carbon molecules, ions, and clusters

1989 ◽  
Vol 89 (8) ◽  
pp. 1713-1747 ◽  
Author(s):  
William Weltner ◽  
Richard J. Van Zee
Keyword(s):  
Carbon Molecules

Substrate channels revealed in the trimericLactobacillus reuteribacterial microcompartment shell protein PduB

2012 ◽  
Vol 68 (12) ◽  
pp. 1642-1652 ◽  
Author(s):  
Allan Pang ◽  
Mingzhi Liang ◽  
Michael B. Prentice ◽  
Richard W. Pickersgill
Keyword(s):  
Tandem Repeats ◽  
Lactobacillus Reuteri ◽  
Protein Complexes ◽  
Protein Subunits ◽  
Shell Protein ◽  
Domain Structures ◽  
Bacterial Microcompartment ◽  
Major Shell ◽  
Carbon Molecules ◽  
Trimeric Structure

Lactobacillus reuterimetabolizes two similar three-carbon molecules, 1,2-propanediol and glycerol, within closed polyhedral subcellular bacterial organelles called bacterial microcompartments (metabolosomes). The outer shell of the propanediol-utilization (Pdu) metabolosome is composed of hundreds of mainly hexagonal protein complexes made from six types of protein subunits that share similar domain structures. The structure of the bacterial microcompartment protein PduB has a tandem structural repeat within the subunit and assembles into a trimer with pseudo-hexagonal symmetry. This trimeric structure forms sheets in the crystal lattice and is able to fit within a polymeric sheet of the major shell component PduA to assemble a facet of the polyhedron. There are three pores within the trimer and these are formed between the tandem repeats within the subunits. The structure shows that each of these pores contains three glycerol molecules that interact with conserved residues, strongly suggesting that these subunit pores channel glycerol substrate into the metabolosome. In addition to the observation of glycerol occupying the subunit channels, the presence of glycerol on the molecular threefold symmetry axis suggests a role in locking closed the central region.

scholarly journals C2 and Diffuse Interstellar Bands

2013 ◽  
Vol 9 (S297) ◽  
pp. 121-124 ◽  
Author(s):  
M. Kaźmierczak ◽  
M. Schmidt ◽  
T. Weselak ◽  
G. Galazutdinov ◽  
J. Krełowski
Keyword(s):  
Interstellar Clouds ◽  
Physical Conditions ◽  
Diffuse Interstellar Bands ◽  
Carbon Molecules ◽  
Long Chain

AbstractC2, the simplest multicarbon molecule is a useful astronomical tool, because the analysis of its lines allows to determine the physical conditions in interstellar clouds. C2 abundances give information about the chemistry of interstellar clouds, especially on the pathway to the formation of long-chain carbon molecules, which may be connected with carriers of diffuse interstellar bands (Douglas 1977, Thorburn et al. 2003). Here we summarize all relations between C2 and diffuse interstellar bands (DIBs).

Introduction: Why oxygen chemstry?

1992 ◽  
Author(s):  
Donald T. Sawyer ◽  
R. J. P. Williams
Keyword(s):  
Organic Chemistry ◽  
Nineteenth Century ◽  
Chemical Properties ◽  
First Year ◽  
Chemistry Curriculum ◽  
Design And Synthesis ◽  
Carbon Molecules ◽  
Living Organisms ◽  
Fixed Array ◽  
Oxygen Atoms

The fundamental premise of chemistry is that all matter consists of molecules. The physical and chemical properties of matter are those of the constituent molecules, and the transformation of matter into different materials (compounds) is the result of their reactions to form new molecules. A molecule consists of two or more atoms held in a relatively fixed array via valence-electron orbital overlap (covalent bonds; chemical bonds). In the nineteenth century chemists focused on the remarkable diversity of molecules produced by living organisms, which have in common the presence of tetravalent carbon atoms. As a result the unique versatility of carbon for the design and synthesis of new molecules was discovered, and the subdiscipline of organic chemistry (the science of carbon-containing molecules) has become the dominant part of the discipline. Clearly, the results from a focus on carbon-based chemistry have been immensely useful to science and to society. Although most molecules in biological systems [and produced by living organisms (particularly aerobic systems)] contain oxygen atoms as well as carbon and hydrogen (e.g., proteins, nucleic acids, carbohydrates, lipids, hormones, and vitamins), there has been a long tradition in all of chemistry to treat oxygen atoms as “neutral counterweights” for the “important,” character-determining elements (C, H, Al, Si, Fe, I) of the molecule. Thus, chemists have tended to take the most important element (oxygen) for granted. The chemistry curriculum devotes one or two year-courses to the chemistry of carbon (“Organic Chemistry”), but only a brief chapter on oxygen is included in the first-year and the inorganic courses. However, if the multitude of hydrocarbon molecules is from the incorporation of oxygen atoms in single-carbon molecules argues against the assignment of a “neutral character” for oxygen atoms [e.g., Cn(graphite), CH4(g), CH3OH(1), CH2(O)(1), HC(O)OH(1), (HO)2C(O)(aq), CO(g), CO2(g)]. Just as the focus of nineteenth century chemists on carbon-containing molecules has produced revolutionary advances in chemical understanding, and yielded the technology to synthesize and produce useful chemicals, polymers, and medicinals; I believe that a similar focus on oxygen chemistry is appropriate and will have analogous rewards for chemistry, biochemistry, and the chemical process technologies.

scholarly journals André Boivin: A pioneer in endotoxin research and an amazing visionary during the birth of molecular biology

2019 ◽  
Vol 26 (3) ◽  
pp. 165-171
Author(s):  
Jean-Marc Cavaillon
Keyword(s):  
Molecular Biology ◽  
Premature Death ◽  
Biological Chemistry ◽  
Scientific Contribution ◽  
Bacterial Dna ◽  
Dna And Rna ◽  
Assistant Director ◽  
Pyrimidine Bases ◽  
Carbon Molecules ◽  
Set Up

André Boivin (1895–1949) started his career in Marseille as a biochemist. Soon after the discovery of insulin, he worked on its purification, allowing for the treatment of local patients. He later moved to Strasbourg and set-up a microtitration technique of small carbon molecules and a method for quantifying purine and pyrimidine bases. His main scientific contribution occurred in Bucharest, where he was recruited to organize the teaching of medicinal chemistry. Together with Ion and Lydia Mesrobeanu, at the Cantacuzene Institute, they were the first to characterize the biochemical nature of endotoxins, which he termed the “glucido-lipidic antigen.” After joining the Institut Pasteur annex near Paris, he worked with Gaston Ramon pursuing his research on smooth and rough LPS. Additionally, with Albert Delaunay, he researched the formation of exotoxins and antibodies (Abs). He was nominated assistant-director of the Institut Pasteur in 1940. He initiated research on bacterial DNA and RNA, and was the first to hypothesize on how RNA fits into gene function. In 1947 he moved for a second time to Strasbourg, accepting a position as a Professor of Biological Chemistry. After his premature death at the age of 54, the French academies mourned his loss and recognized him as one of their outstanding masters of biochemistry, microbiology, immunology, and molecular biology.

Reaction of silicon tetrachloride and silane with small carbon molecules

1970 ◽  
Vol 9 (6) ◽  
pp. 1578-1580 ◽  
Author(s):  
Jehuda Binenboym ◽  
Riley Schaeffer
Keyword(s):  
Silicon Tetrachloride ◽  
Carbon Molecules

Reactor Network Modeling of Stability and Emissions of Hydrogen and Natural Gas Blends for a Piloted Gas Turbine Combustor

2020 ◽  
Author(s):  
Candy Hernandez ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Chemical Reactor ◽  
Experimental Results ◽  
Fuel Composition ◽  
Gas Turbine Combustor ◽  
Flammability Limits ◽  
Lean Premixed ◽  
Carbon Molecules

Abstract Lean-premixed (LPM) gas turbines have been developed for stationary power generation in efforts to reduce emissions due to strict air quality standards. Lean-premixed operation is beneficial as it reduces combustor temperatures, thus decreasing NOx formation and unburned hydrocarbons. However, tradeoffs occur between system performance and turbine emissions. Efforts to minimize tradeoffs between stability and emissions include the addition of hydrogen to natural gas, a common fuel used in stationary gas turbines. The addition of hydrogen is promising for both increasing combustor stability and further reducing emissions because of its wide flammability limits allowing for lower temperature operation, and lack of carbon molecules. Other efforts to increase gas turbine stability include the usage of a non-lean pilot flame to assist in stabilizing the main flame. By varying fuel composition for both the main and piloted flows of a gas turbine combustor, the effect of hydrogen addition on performance and emissions can be systematically evaluated. In the present work, computational fluid dynamics (CFD) and chemical reactor networks (CRN) are created to evaluate stability (LBO) and emissions of a gas turbine combustor by utilizing fuel and flow rate conditions from former hydrogen and natural gas experimental results. With CFD and CRN analysis, the optimization of parameters between fuel composition and main/pilot flow splits can provide feedback for minimizing pollutants while increasing stability limits. The results from both the gas turbine model and former experimental results can guide future gas turbine operation and design.

scholarly journals Cumulene Carbenes in Space and in the Laboratory

1992 ◽  
Vol 150 ◽  
pp. 23-24
Author(s):  
J. M. Vrtilek ◽  
C. A. Gottlieb ◽  
T. C. Killian ◽  
P. Thaddeus ◽  
J. Cernicharo ◽  
...  
Keyword(s):  
New Family ◽  
Carbon Chains ◽  
Carbon Molecules

Astronomical searches for H2CCC and H2CCCC, based on frequencies from our laboratory identifications, have resulted in detections toward TMC-1 and IRC+10216. These new interstellar species are possibly the first of a new family of highly polar carbon chains; they are only the second and third carbenes (carbon molecules with two nonbonded electrons) known in space.

Long chain carbon molecules and diffuse interstellar lines

Nature ◽  
1979 ◽  
Vol 278 (5706) ◽  
pp. 722-723 ◽  
Author(s):  
G. F. MITCHELL ◽  
W. T. HUNTRESS
Keyword(s):  
Carbon Molecules ◽  
Long Chain
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