User:Douglian30/sandbox/talk drafts
Rev. Hodgson and the foundation of WBA
[edit]The article on Robert Hodgson (diplomat) states that his father, the Reverend Robert Hodgson, was "founder of West Bromwich Albion Football Club", without citation. The history on the WBA website and in Gavin McOwan's book describe the roots in Salter's and the name change from Strollers to Albion, but do not name specific founders (just the first reported players). Father and son were associated with the town of West Bromwich in the 1870s, but was there any link to WBA FC? If there is no reliable, sourced information that there was, I will delete the phrase in the Hodgson article.
Opening lead paragraph (May 2023)
[edit]The statement "Cholesterol is any of a class of certain organic molecules called lipids." is wrong. Cholesterol is not "any of a class", it is a single, (stereo)specific chemical compound. It is a member of the sterols, which (as stated and explained in the Sterol article) are a class of steroid, having a 3-hydroxy group, not a modified steroid. The scope note for the MeSH term Cholesterol reads "The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils". This could be the basis for a revised opening to the lead section, namely:
"Cholesterol is the principal sterol (a steroid with a hydoxy group in position 3) of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.<ref name=pubchem/><ref>{{MeshName|Cholesterol|2013}}</ref>
Also, the sentence "When chemically isolated, it is a yellowish crystalline solid." is at odds with the entry "Appearance = white crystalline powder" under Properties. Yellow coloration may have resulted from imperfect purification in earlier isolations and the inclusion of the sentence in the lead section is probably unnecessary anyway.
The present text of the lead section needs to be corrected ASAP. Unless there are any adverse comments or suggested improvements, I'll edit the text.
Litvinov – Seeds
[edit]The belittling of the French ambassador was accidental. On 29 March, I clarified and added links for the CE's [who?] flags, including Seeds, but neither of us paid attention to unnamed persons. There are some further links that I have now added (Ilya Ehrenburg, Andrey Andreyevich Andreyev, Georgi Dimitrov) and also Gen. Lesley J. McNair (after inserting a comma to indicate that he hadn't been elevated to VP!).
Disagreement in numbers
[edit]The "Clinical Significance" section, the last paragraph, seems to have some weird numbers in it. One example: "These groups were more likely to die of cancer, liver diseases, and mental diseases with very low total cholesterol, of 186 mg/dL (10.3 mmol/L) and lower." -- 10.3 is not very low, it's very high. Someone should run a check there. --CopperKettle (talk) 05:54, 18 July 2023 (UTC)
Tautomers and nomenclature
[edit]Some of the chemical information in the article is questionable, including the (unreferenced, but ranked) list of named tautomers and some of the structures and names in the linked external datasets listed in the Chemical Infobox. Also, the article does not cover recent publications. An update of the Chemistry section might include:
The general statement that creatinine tautomers are in equilibrium is not really accurate under normal conditions. In aqueous environments, both hydrogen bonding with the inner solvation-shell of water molecules and overall polar-solvent effects stabilise the amino form, with pH also having a significant effect [with high pH increasing ring cleavage to (re)form creatine]. Thus amine-imine tautomerism may not be relevant in a biological context (other than in possible mechanistic routes) and keto-enol tautomerism probably can be disregarded.
The Wikipedia article on Tautomers covers implications for databases, noting the advantages of notation, but this leaves the problem of nomenclature if Creatinine is to be named systematically, since such names are specific to a single structure. Fortunately, on the basis of the above (but not the existing article), it seems reasonable to base the preferred name on the amine structure. Unfortunately, the quality of structural and naming information for Creatinine in the Chemical Infobox and some of the external databases listed is variable, to put it politely and in the light of the text proposed above. To enumerate the points:
- IUPAC Preferred Name: Naming of the parent cycle of the 2-amino-4-one and 2-imino-4-one tautomers differs because in the former the ring contains unsaturation, whereas in the latter it is saturated (but with conjugation through the 3-N lone pair), resulting in the stems "diazole" and "diazolidine", respectively, under Hantzsch–Widman rules. In the 2-amino structure, the partial ring saturation is reflected by indicated hydrogen (xH) and "dihydro" terms, with appropriate locants.
- Whether "Other names" should just include variants for the 2-amino structure or also for the 2-imino structure is a moot point.
- CHEBI:16737 and CHEMBL65567 (Creatinine) give the structure and names of the 2-imino form, as does DrugBank DB11846 and KEGG D03600.
- ChemSpider 21640982 (Creatinine) gives the structure and names of the 2-amino-4-hydroxy compound with a doubly unsaturated diazolidine ring.
- ECHA InfoCard 100.000.424 and EC number: 200-466-7 use 2-imino-1-methylimidazolidin-4-one as the heading for Creatinine.
- MeSH term Creatinine (D003404) - sanity at last!
- PubChem CID 26009888 is 2-amino-1-methyl-1H-imidazol-4-ol, an isomer of Creatinine, but according to the reference cited above not a significant tautomer. The PubChem CID for Creatinine is 588; it supplies the 2-amino-4-one structure, but includes the 2-imino form amongst the list of synonyms. It was the illogically of calling Creatinine a minor tautomer of Creatinine that originally suggested that there might be problems in the information for the compound.
- UNII: AYI8EX34EU uses the 2-amino structure, but supplies some 2-imino names. The linked Inxight Drugs database has the 2-amino structure but gives 2-Imino-1-methylimidazolidin-4-one as the "Systematic Name", relegating 2-amino names to "Common Name"s!
- CompTox Dashboard (EPA) DTXSID8045987 shows the 2-imino structure and provides "IUPAC Name: 2-Imino-1-methylimidazolidin-4-one".
This seems an unsatisfactory situation for the information on a biologically significant compound, with it being unclear why databases prefer a structure that is not normally observed in reality. Is this really the case and what should be done about it?
Polyunsaturated fats redirection
[edit]The redirection from Polyunsaturated fats to Polyunsaturated fatty acids is inappropriate, because these are distinctly different, if related, concepts. Polyunsaturated fatty acids, together with the corresponding Saturated fatty acids and Mono-unsaturated fatty acids terms are 3 mutually exclusive classes of chemical compound. On the other hand, Polyunsaturated fats and the corresponding terms for saturates and mono-unsaturates are nutritional constructs used to quantify the amounts of each type of fat in a food based on their fatty acid profiles. This is well illustrated in the article on Triglycerides, where the structural diagram of a mixed triglyceride shows a molecule that is one-third saturated fat, one-third mono-unsaturated fat and one-third polyunsaturated fat (the caption text "an unsaturated fat triglyceride" should be read as "an unsaturated fat-triglyceride", not "an unsaturated-fat triglyceride").
The fat and corresponding fatty acid terms are NOT synonymous. The fatty acid terms name specific categories of chemical compound, whereas the fat terms represent derived concepts, with compositional values calculated. The logical difference is well illustrated in the article on Triglyceride, where the structure of a "mixed triglyceride" shows a molecule that contributes (nearly) one-third each of saturated, mono-unsaturated and polyunsaturated fat. The "nearly" arises because the calculation excludes the weight contributed by the glycerol backbone. This is explained in more detail in Danish Food Informatics's description of Fatty acids in foods. Thus the relationship between the fat and corresponding fatty acid terms are See also ones, not See redirections. To avoid needless repetition, the description of the fat terms might be generalised in the Fat#Nutritional_and_health_aspects section or in a new, linked article on Types of fat.
BNF revision
[edit]The current version of the BNF article has broken links, incomplete references and is not particularly informative. Rather than make separate comments or individual edits, it is perhaps simpler to do a full redraft, as follows:
This revision has been prepared without the knowledge of BNF, although I intend to advise them of it. To allow a little time for comments, I plan to replace the existing article text on 15 September.
Definitions for types of fat
[edit]Now that it seems decided, if not implemented, that information covering each type of Fat and the corresponding set of Fatty acids should form a single, combined article, named according to the Fat rather than the Fatty acids, it needs to be decided what editing of the articles is needed to describe the types of fat adequately. The starting point should be to describe the article subject correctly. For example, in MUF, the statement "Monounsaturated fats are triglycerides containing one unsaturated fatty acid." is wrong. Triglycerides with 1, 2 or 3 MUFAs all contribute to MUF, only in differing amounts. The articles on SF (Saturated fat), MUF and PUF make no mention at all of the legal definitions of the terms, as mandated for the nutritional labelling of foods, although these are precise. These have minor variations, for example between the US and Europe, but these definitions should be clear as they determine the information most seen by consumers. These defined terms also include Total fat (TF). FT redirects to Fat, an article that emphasises that Fat can have varying meanings. FT is mentioned several times in the article, but is undefined.
Apart from definitions, much further editing is needed in the articles relating to fats. For example, in PFA#Reactions, how many edits are required in the paragraph "Hydrogenation of PUFAs gives less saturated derivatives. For unsaturated products from partial hydrogenation often contain some trans isomers. The trans monounsaturated C20 species elaidic acid can be prepared in this way."? The articles in this area are important and do need further attention.
Analysis and quantification draft
[edit]Fat types 2
[edit]Yes, a good step forward, but a little more is needed; it does not take account of the point that I made above about how 1, 2 or 3 MUFAs in a triglyceride contribute to the MUF total. Consider a hypothetical "pure" triglyceride in which only the same set of 3 fatty acids occur in the triglyceride molecules. If one of the three fatty acids is a MUFA, then 100g of the triglyceride will contribute 33g to the MUF total. However, if two of the three are MUFAs, then the contribution is 67g and if all three are MUFAs, the contribution is 100g. None of the existing articles on the types of fat make this clear, although it is key to any quantitative work using food composition data and to meeting food labelling regulations. I intend to draft an extra section, initially for the PUFA/PUF article, on "Analysis and quantification", which I will post for discussion. Hopefully a clear and concise description of the analysis of fatty acids in foods and the construction of the fatty acid/fat totals from these analytical results will improve the understandability (and accuracy) of the articles.
Definition of MUF
[edit]The existing definition of MUF is somewhat inaccurate and misleading. An improved text for the lead section might read:
On the basis of this definition, the opening sentence of the Molecular description section is incorrect, as is the caption of the molecular structure diagram. Certainly this shows a monounsaturated triglyceride, but it is not a MUF. It contains two saturated fatty acids and one MUFA. Thus it contributes two parts saturated fat and one part MUF.
Also, the statement "Almost invariably that fatty acid is oleic acid (18:1 n−9)" may apply in some cases, but is wide of the mark for many foods. For example, using data from the UK tables, 100g of raw herring contains 1.06g 16:1, 1.50g 18:1, 1.26g 20:1 and 2.01g 22:1. Further, highlighting the values for MUF in red and green (why the difference?) in the table risks carrying an implication that is not intended.