Membrane active substances

Increasing pH values also affect the surfaces of the microbe cells they become more negatively charged. This, in turn, naturally increases the affinity of cationogenic, membrane-active substances, to the cell surface and hence the intensity of their effects on it. Examples are provided by quaternary ammonium compounds (III.16.1), biguanides (III.16.2) and dibenzamidines (III.IO). 

The microbicidal acids belong to the membrane-active substances. Typical is that acids display significant antimicrobial activity only when they are present in their undissociated state. A carboxylic acid for instance dissociates according to the following equation... 

Also salicylanilides (2-hydroxybenzanilides), long chain A-alkyl-salicylamides and carbanilides (urea derivatives) belong to the amide compounds with antimicrobial action. They are membrane-active substances, i.e. very small concentrations suffice to achieve microbistatic effects whereas microbicidal effects call for much higher addition rates. 

Active substances. Target specificity is a non-desired property of a technical microbicidal active molecule. The applied molecules are either classified as membrane-active substances or as reactive electrophiles. Some molecules can not be clearly assigned to one of the two categories while showing both modes of actions. See chapter 2. 

Membrane-active substances used in paint in-can preservatives are e.g. 

Membranes and Osmosis. Membranes based on PEI can be used for the dehydration of organic solvents such as 2-propanol, methyl ethyl ketone, and toluene (451), and for concentrating seawater (452—454). On exposure to ultrasound waves, aqueous PEI salt solutions and brominated poly(2,6-dimethylphenylene oxide) form stable emulsions from which it is possible to cast membranes in which submicrometer capsules of the salt solution ate embedded (455). The rate of release of the salt solution can be altered by surface—active substances. In membranes, PEI can act as a proton source in the generation of a photocurrent (456). The formation of a PEI coating on ion-exchange membranes modifies the transport properties and results in permanent selectivity of the membrane (457). The electrochemical testing of salts (458) is another possible appHcation of PEI. 

The paper presents the experimental and theoretical data regarding the realization and characterization of three liquid-membrane electrodes, which have not been mentioned in the specialized literature so far. The active substances whose solutions in nitrobenzene have constituted the membranes on a graphite rod, are simple complex combinations of the Cu(II) and Ni(II) ions with Schiff base N-[2-thienylmethylidene]-2-aminothiophenol (TNATPh). 

The slightly soluble ion pair was used as electrode-active substance in a plastered membrane of an ion-selective electrode (ISE) for these alkaloids. 

Suitable active substances for the membrane of the Ba ISE are ionophore XX (nonylphenoxy-poly(ethylenoxy)ethanol, Igepal CO-880, Antarox CO-880) [123,... 

There is no doubt that cerebral lipids, and EEA-derived LC-PUFAs in particular, have significant direct and indirect actions on cerebral function. Not only does the lipid composition of neural membranes affect the function of their embedded proteins, but also many LC-PUFAs are converted to neurally active substances. There is good evidence that psychiatric illness is associated with depletion of EFAs and, crucially, that supplementation can result in clinical amelioration. Ar well as challenging traditional views of aetiology and therapeutics in psychiatry, the clinical trial data may herald a simple, safe and effective adjunct to our standard treatments for many disabling conditions. 

The most universal transport systems are those involved in the transport of the ubiquitous inorganic ions, sodium, potassium and calcium1. The sodium pump counteracts passive water movement across the cell membrane by removing sodium ions together with chloride or other anions from the cytoplasm to lower its content of osmotically active substances. In most cells, however, the elimination of sodium ions is connected with an accumulation of potassium ions6. For three sodium ions leaving the cell two potassium ions are taken up9,10). The resulting concentration... 

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