In this paper I aim to show that a certain law of nature, namely that common salt (sodium chloride) dissolves in water, is metaphysically necessary. The importance of this result is that it conflicts with a widely shared intuition that the laws of nature (most if not all) are contingent. There have been debates over whether some laws, such as Newton’s second law, might be definitional of their key terms and hence necessary. But the law that salt dissolves (...) in water is not that kind of law. The law statement ‘salt dissolves in water’ is clearly synthetic. It appears a classic case of a contingent law. We like to believe that there are possible worlds in which the laws of nature are different and in which salt does not dissolve in water. (shrink)

What, precisely, is `salt'? It is a certainwhite, solid, crystalline, material, alsocalled sodium chloride. Does any of that solidwhite stuff exist in the sea? – Clearly not.One can make salt from sea water easily enough,but that fact does not establish thatsalt, as such, is present in brine. (Paper andink can be made into a novel – but no novelactually exists in a stack of blank paper witha vial of ink close by.) When salt dissolves inwater, what is present (...) is no longer `salt' butrather a collection of hydrated sodium cationsand chloride anions, neither of which isprecisely salt, nor is the collection. Theaqueous material in brine is also significantlydifferent from pure water. Salt may beconsidered to be present in seawater, but onlyin a more or less vague `potential' way.Actually, there is no salt in the sea. In bothancient and modern treatments of otherimportant chemical concepts, including thenotions of `element', related complication,especially polysemy (terms with multiplemeanings), also occurs.In a recent paper, Paul Needham discussed the(predicable) properties of chemical substances,phases, and solutions. He provided a valuablecharacterization of cases in which severalquantities occupy the same space. He alsoconcluded that solution properties are not`intensive', because solvent and solute do nothave parts in common. He tacitly assumed thatingredients are not altered by their inclusionin a solution. This may be the case in somespecial cases (deutero-benzene dissolved inbenzene, say) but is not true in general – andcertainly does not apply to the case of brine,which Needham used as an example – since theions that exist in the solution, and also theaqueous material there, are quite differentfrom the pure ingredients used in making thesolution. An adequate theory of wholes andparts (mereology) must take into account thatwhen individuals enter combinations ofinteresting sorts they no longer are the verysame individuals that existed prior to thecomposition. It appears that no such formaltheory now actually exists. (shrink)

High blood pressure (HBP) is a multifactorial clinical condition characterized by high and sustained levels of blood pressure (BP), and the presence of elevated BP in childhood is predictor of hypertension in adult life. Studies have shown a positive correlation between sodium chloride ingested in the diet and blood pressure values. This study aims to evaluate the consumption of added salt before and after awareness of risk, by high school students. This occurred for three days in the refectory, (...) where students received illustrative brochure with information about sodium intake; exhibition of a poster illustrating foods with their respective equivalent amount of sodium and sodium chloride, exemplifying the maximum recommended amount of consumption per day. For five days, before and after gaining awareness, it the amount of consumption of sachets of salt was accounted. Statistical analyzes were performed by Student's Test, with a confidence interval of 95%. During the study period were served on average 128.3 meals. Before the awareness of sodium consumption of risks, of 820mg and 330mg sodium salt was consumed an average per individual, and thereafter, 640mg and 260mg, respectively (p=0,043). Simple Nutrition Education Strategies in short term were effective for improving the consumption of added salt in adolescents. (shrink)

This essay explores histories of common salt, sodium chloride, using concepts and methods from media theory. It contributes to research on media and environment and the general ‘material turn’ taken across the Humanities. I conceive of salt as what Peters calls an ‘elemental’ medium so as to show, first, the imbrication of naturally-occurring substances in the operations and supply chains of digital culture. Second, the many lives salt has lived materially, in techniques of survival and exchange, and metaphorically, (...) in cultural expression, complicate conventional understandings of media. In showing how salt performs three functions, processing, storage, and transfer, which Kittler ascribed to technical and symbolic media, I argue for a more expansive use of ‘mediation’ as a bridge concept that speaks to matters of nature and culture, Arts and Science, and to account for deep histories of extraction and economy that shape digital culture and global supply chains. (shrink)

This paper pertains to the alleged euthanising of a 3-month-old infant at Sweden's Astrid Lindgren Children’s Hospital in September 2008 and the subsequent effects upon the doctor who was charged with, but eventually acquitted of, violating Sweden's anti-euthanasia law. Lynøe and Leijonhufvud1 contend that particular modifications should be made to the existing Swedish regulatory regime in order to secure what they refer to as ‘physician safety’—that is, protection against unnecessary lawsuits that may well endanger a doctor's reputation and career. Undoubtedly, (...) many things went wrong at the Astrid Lindgren Children's Hospital. As the authors acknowledge, there occurred the initial botched delivery, the overdose of sodium chloride as well as the unrecorded administration of a toxic level of thiopental to the patient either by the defendant or by another doctor. The only thing the authors regard as unproblematic within this series of events is the determination by the Swedish Board of Health and Welfare that the doctor-defendant's behaviour ‘accords with good clinical practice’ that serves as the principal assumption upon which they contend that the system, rather than the doctors’ behaviour, is to be faulted.It would be easier to sympathise with the authors’ position had they explained more fully the basis of the Swedish Board's determination. …. (shrink)

Chloride channels are probably found in every cell, from bacteria to mammals. Their physiological tasks range from cell volume regulation to stabilization of the membrane potential, signal transduction, transepithelial transport and acidification of intracellular organelles. These different functions require the presence of many distinct chloride channels, which are differentially expressed and regulated by various stimuli. These include various intracellular messengers (like calcium and cyclic AMP), pH, extracellular ligands and transmembrane voltage. Three major structural classes of chloride channels (...) are known to date, but there may be others not yet identified. After an overview of the general functions of chloride channels, this review will focus on these cloned chloride channels: the CLC chloride channel family, which includes voltage‐gated chloride channels, and the cystic fibrosis transmembrane regulator (CFTR), which performs other functions in addition to being a chloride channel. Finally, a short section deals with GABA and glycine receptors. Diseases resulting from chloride channel defects will be specially emphasized, together with the somewhat limited information about how these proteins work at the molecular level. (shrink)

The sodium cotransport systems comprise an important group of transport proteins which are involved in the transport of a variety of organic and inorganic solutes across the cellular membrane of animal cells. These systems play a central role in a wide variety of cellular and biochemical processes. We summarize here the current state of knowledge regarding the variety, structure and regulation of this important group of membrane proteins.

Far from being of mere historical interest, concept horse-style expressibility problems arise for versions of type-theoretic semantics in the tradition of Montague. Grappling with expressibility problems yields lessons about the philosophical interpretation and empirical limits of such type-theories.