Sodium sensing

Matrix mechanisms of sodium Urushi and PVC/ISFETs. The electrochemical characteristics, such as linear response range, sensitivity, selectivity and response time of the Urushi matrix ISFETs are similar to those of the PVC matrix ISFETs. The reason of the same characteristics is discussed from the standpoint of matrix mechanisms as follows. The obtained results indicate that these characteristics are mainly determined not by polymeric matrix materials but by sodium-sensing materials, including the membrane solvent (NPOE etc.). Therefore, it is considered that the polymeric matrix materials, such as PVC and Urushi only act as a hydrophobic support polymer and that the major part of surface of the matrix membrane should be covered with the membrane solvent containing the Na ionophore. 

PPy is known to exhibit anionic or cationic potentiometric responses depending on the doping ion. PPy films doped with mobile inorganic anions show anionic sensitivity, while PPy films doped with anions of low mobility such as sulfate, large organic anions, or polyanions show cationic sensitivity. This bifunctionality of ionic and redox sensitivity makes PPy apphcable as an all-sohd-state, ion-selective electrode. All-solid-state, potentiometric PPy sensors were developed for potassium and sodium sensing, which showed better response time, selectivity and most importantly long-term stabihty than the coated wire electrode [130]. 

Sannicolo, F., et al. 1998. Highly ordered poly(cyclopentabithiophenes) functionalized with crown-ether moieties for lithium- and sodium-sensing electrodes. Chem Mater 10 2167. 

Mode of Action. DDT and its analogues specifically affect the peripheral sense organs of insects and produce violent trains of afferent impulses that result in hyperactivity, convulsions, and paralysis. Death results from metaboHc exhaustion and the production of an endogenous neurotoxin. The very high lipophilic nature of these compounds faciUtates absorption through the insect cuticle and penetration to the nerve tissue. The specific site of action is thought to be the sodium channels of the axon, through inhibition of Ca " ATPase. 

If the equilibrium were established rapidly, reduction of the free ketone as it formed would result in a substantial loss of product. Lithium enolates are more covalent in character than are those of sodium and potassium and consequently are the least basic of the group. This lower thermodynamic basicity appears to be paralleled by a lower kinetic basicity several workers have shown that lithium enolates are weaker bases in the kinetic sense than are those of sodium and potassium." As noted earlier, conjugated enones... 

Natron, n. soda, in the following senses (1) sodium carbonate, Na2COa ( kohlensaurea Natron ) (2) sodium hydrogen carbonate, NaHCOa ( doppcltkohlensaures Natron ) (3) sodium hydroxide or caustic soda, NaOH, usually called Atznatron (4) in older names, sodium oxide, NajO (as in schwefel-saures Natron, sodium sulfate), -aiaun,... 

When a metal such as sodium (Na) or calcium (Ca) reacts with a nonmetal such as chlorine (Cl2), the product is ordinarily an ionic compound. The formula of that compound (e.g., NaCl, CaCl2) shows the simplest ratio between cation and anion (one Na+ ion for one Cl ion one Ca2+ ion for two Cl- ions). In that sense, the formulas of ionic compounds are simplest formulas. Notice that the symbol of the metal (Na, Ca) always appears first in the formula, followed by that of the nonmetal. 

Now by taking one more step we can view acid-base reaction in a broader sense. Suppose we mix aqueous solutions of ammonium chloride, NH4CI, and sodium acetate, CH3COONa. A sniff indicates ammonia has been formed. Reaction occurs,... 

But there is a second notion, which Mendeleev sometimes called "real dements," in order to indicate their more fundamental status. In Bis sense, Ihe eh emants represent abstract substances that lack what wc normally regard as properties and that represent the form that elements take when they occur in compounds. For example, sodium and chlorine as simple substances—a grey mrt.il and a gicmish gas respectively—are nol literally present in the compound sodium chloride (table salt). Mendeleev would have said Brat sodium and chlorine are present In the compound as the abstract or "real ctemanls. ... 

Sensory receptors expressed in particular in taste receptor cells of the taste buds that sense the five basic tastes salt, sour, sweet, bitter and umami (glutamate taste). Sodium type ion channels sense salty taste whereas sour taste is transduced by potassium type ion channels. The underlying cause of sweet, bitter, and umami tastes is the selective activation of different groups of G protein coupled receptors that discriminate between sweet, bitter, and umami tasting molecules. 

According to [4], IOS consists typically of sodium (3-hydroxysulfonate (85%), sodium alkenesulfonate (10%), sodium y/5-hydroxysulfonates (5%), and residual sultones (usually less than 6 ppmw on active matter). IOS too can be regarded as a surfactant system in the sense referred to above. 

However, the reactants are present as solutions, and once mixed do not in any real sense contain silver nitrate and sodium chloride as separate substances (even in the hypothetical instant before precipitation occurs). Example 4 might best be rewritten... 

In contradistinction to site-specific molecules there are other toxins which, in a sense, create their own specificity. Thus ionophore toxins, by opening up the cell membrane to sodium and calcium ions, create their own specificity. Prime examples of this are found in cytolytic toxins in general, and jellyfish toxins and palytoxin in particular. 

All sodium salts are soluble, and so are all nitrate salts, so It makes sense that neither of these ions participates in a solubility equilibrium. Furthermore, nitrate and sodium cations are neither acidic nor basic, so it makes sense that neither participates in an acid-base equilibrium. 

Hydrogen ions accumulate in tissue damaged by inflammation and ischaemia and so pH is lowered. These protons may activate nociceptors directly via their own family of ion channels as well as sensitising them to mechanical stimulation. Acid-sensing ion channels (ASICS) are a family of sodium channels that are activated by protons — of special interest is one type found only in small dorsal root ganglion neurons that possibly are responsible for activation of nociceptors. Although the transduction of mechanical stimuli is poorly understood, ASICs are closely related to channels that respond to stretch. 

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