A New Class of Labile Surfactants that Break Down to Non-surface Active Products upon Heating or after a Pre-set Time, without the Need for a pH Change

A new class of labile surfactants that break down at a controllable rate without the need for a change in pH will be presented. The invention has been patented by YKI Institute for Surface Chemistry, and is based on use of β-keto acids or their salts as surface-active compounds. These surfactants spontaneously break down through decarboxylation, to form an oil-like ketone and CO2/HCO3 −/CO3 2− depending on pH. The rate of breakdown can be controlled within a wide range by temperature or by certain additives, but, unlike most cleavable surfactants, a change in pH is not needed. Furthermore the surfactants can be conveniently activated from a stabile precursor just before use, and one (of many possible) precursors of this kind is already available on the industrial scale in the form of a well-known chemical that is FDA-approved in other, non-surfactant, applications. The compound in question, alkyl ketene dimer (AKD), is produced in large scale by a number of large chemical producers today, and used for hydrophobization of paper. The present article gives an overview of the surfactant chemistry, with focus on recent studies of the kinetics of activation of the surfactant precursor and breakdown kinetics of the labile surfactant at different conditions. Furthermore, possible industrial applications of the surfactant will be discussed, with one example taken from a recent feasibility study performed within the car washing area.

Molecular markers for UV-B stress in plants: alteration of the expression of four classes of genes in Pisum sativum and the formation of high molecular mass RNA adducts

Sixteen ultraviolet-B radiation-regulated pea genes were identified. Functionally, the corresponding proteins were divided into four groups. (i) Chloroplast-localized proteins. Genes for these proteins were down-regulated, underlining the deleterious effects of UV-B on this organelle. A novel down-regulated photosystem I light-harvesting chlorophyll a/b-binding protein gene (PsLhcA4), was cloned and sequenced. (ii) Protein turnover enzymes. Levels of mature mRNAs for the PU1 and PsUBC4 genes, encoding proteins of the ubiquitin protein degradation pathway, were up- and down-regulated, respectively, implying alteration of plant cell protein content by changes in both gene expression and protein degradation. (iii) Proteins involved in intracellular signalling. Expression of genes for small GTPases, rab and rho homologues, were altered. (iv) Phenylpropanoid or flavonoid biosynthesis. Expression of three genes encoding enzymes in these pathways were up-regulated and one of them, the novel PsC450R1, was cloned and sequenced. Moreover, unexpected high molecular mass psbA RNA adducts were found to appear after UV-B exposure. In addition, a large increase in corresponding high molecular mass adducts were also found for PsLhcA4, and PsUBC4 mRNA and 23S rRNA. These RNA species do not contain protein and probably appear due to cross-linking of two or more RNA molecules, or are the result of UV-B-induced failure of transcription termination.