The words to catenate and catenation reflect the Latin root catena, "chain".
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Further catenation is rare, although (isoelectronic with carbonate and nitrate) is known.
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If replication forks move freely in chromosomes, catenation of nuclei is aggravated and impedes mitotic segregation.
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This process is based on a typical property of sulfur which is the catenation. In chemistry, catenation is the bonding of atoms of the same element into a series, called a chain. Hence, from a chemical point of view, the inverse vulcanization is similar to the sulfur based crosslinking, i.e. vulcanization, of an unsaturated elastomer, such as natural rubber.
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Carbon-carbon bonds are strong and stable. Through catenation, carbon forms a countless number of compounds. A tally of unique compounds shows that more contain carbon than do not. A similar claim can be made for hydrogen because most organic compounds contain hydrogen chemically bonded to carbon or another common element like oxygen or nitrogen.
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Type IA also requires an exposed single-stranded region within the DNA substrate. The linking number of DNA changes with relaxation. Type IA topoisomerase can catalyze catenation, decatenation, knotting and unknotting of the DNA. There are three classes within the subfamily of type IB topoisomerase: topoisomerase I in eukaryotes, topoisomerase V in prokaryotes, and the poxvirus topoisomerase.
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Structural formula of methane, the simplest possible organic compound. Correlation between the carbon cycle and formation of organic compounds. In plants, carbon dioxide formed by carbon fixation can join with water in photosynthesis (green) to form organic compounds, which can be used and further converted by both plants and animals. Carbon can form very long chains of interconnecting carbon–carbon bonds, a property that is called catenation.
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Nitrogen does not share the proclivity of carbon for catenation. Like carbon, nitrogen tends to form ionic or metallic compounds with metals. Nitrogen forms an extensive series of nitrides with carbon, including those with chain-, graphitic-, and fullerenic-like structures. It resembles oxygen with its high electronegativity and concomitant capability for hydrogen bonding and the ability to form coordination complexes by donating its lone pairs of electrons.
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A number of diborylene complexes have also been described. The first of these, [(η5-C5Me5)Ir{BN(SiMe3)2}2], was prepared by the photochemical reaction of [(η5-C5Me5)Ir(CO)2] with [(OC)5Cr{BN(SiMe3)2}]. One unusual reaction exhibited by these complexes is coupling of borylene and carbon monoxide ligands. Catenation of an iron borylene complex has generate an iron complex of a tetraboron (B4) chain.
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DNA topology is the tertiary conformations of DNA, such as supercoiling, knotting, and catenation. Topology of DNA can be disrupted by most metabolic processes: RNA polymerase can cause positive supercoils by over-winding the DNA in front of the enzyme, and can also cause negative supercoils by under-winding the DNA behind the enzyme. DNA polymerase has the same effect in DNA replication. Positive and negative supercoiling balance out the entire global topology of the DNA, so overall, the topology remains the same.
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219 . Greater catenation of the Si atoms can be obtained with the halides (SinX2n+2 with n = 14) for the fluorides.A. Earnshaw, N. Greenwood, Chemistry of the Elements, Butterworth-Heinemnann (1997) p. 341 . Thus the polymeric silicon hydrides are formed along with smaller silicon hydride oligomers and hydrogen gas from the spontaneous but slow decomposition, as well as from the accelerated thermolysis, of acyclic and cyclic liquid silanes that are higher in molecular weight than monosilane (SiH4) and disilane (Si2H6).
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Type II family passes a region of duplex (two strands) from the same molecule or a different molecule through a double stranded gap. To summarize, type II cleaves both strands of DNA, that results in a double- stranded break. Topoisomerases can either relieve negative supercoils, both positive and negative supercoils, or induce positive and negative supercoiling in DNA. The enzymes also can promote catenation (when two single circular DNA strands are linked together after replication) and decatenation (the separation of two linked, closed, circular chromosomes), and can also relieve entanglement of linear chromosomes.
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Catenation is the process by which two circular DNA strands are linked together like chain links. This occurs after DNA replication, where two single strands are catenated and can still replicate but cannot separate into the two daughter cells. As type II topoisomerses break a double strand, they can fix this state (type I topoisomerases could do this only if there were already a single- strand nick), and the correct chromosome number can remain in daughter cells. Linear DNA in eukaryotes is so long they can be thought of as being without ends; type II topoisomerases are needed for the same reason.
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Compounds where phosphorus exists in a formal oxidation state of less than III are uncommon, but examples are known for each class. Organophosphorus(0) species are debatably illustrated by the carbene adducts, [P(NHC)]2, where NHC is an N-heterocyclic carbene. With the formulae (RP)n and (R2P)2, respectively, compounds of phosphorus(I) and (II) are generated by reduction of the related organophosphorus(III) chlorides: :5 PhPCl2 \+ 5 Mg → (PhP)5 \+ 5 MgCl2 :2 Ph2PCl + Mg → Ph2P-PPh2 \+ MgCl2 Diphosphenes, with the formula R2P2, formally contain phosphorus-phosphorus double bonds. These phosphorus(I) species are rare but are stable provided that the organic substituents are large enough to prevent catenation.
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New MOF Material With hydrogen Uptake Of Up To 10 wt%. 22 February 2009 Most articles about hydrogen storage in MOFs report hydrogen uptake capacity at a temperature of 77K and a pressure of 1 bar because these conditions are commonly available and the binding energy between hydrogen and the MOF at this temperature is large compared to the thermal vibration energy. Varying several factors such as surface area, pore size, catenation, ligand structure, and sample purity can result in different amounts of hydrogen uptake in MOFs. In 2020, researchers at Northwestern University in the USA reported that NU-1501-Al, an ultraporous metal–organic framework (MOF) based on metal trinuclear clusters, yielded "impressive gravimetric and volumetric storage performances for hydrogen and methane", with a hydrogen delivery capacity of 14.0% w/w, 46.2 g/litre.
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