A highly elastic and stretchable conductive polymer material resulted from blending the conductive polymer poly(3,4‐ethylenedioxythiophene):p‐tosylate and an aliphatic polyurethane elastomer. The blend inherited advantageous properties from its constituents, namely high conductivity of 120 S cm–1 from its conductive polymer component, and elastomeric mechanical properties resembling those of the polyurethane, including good adhesion to various substrates. Stretching of the blend material by up to 50 % resulted in increased conductivity, while subsequent relaxation to the unstretched state caused a decrease of conductivity compared to the pristine blend. These initial changes in conductivity were reproducible on further cycling between 50 % stretching and the unstretched state for at least 10 cycles. Stretching beyond 50 % resulted in decreasing conductivity of the blend but with substantial conductivity remaining even when stretched by 200 %. Optical, mechanical, and thermal properties of the blend, as well as high resolution electron microscopy of bulk cross‐sections, suggest that the system is a single phase and not two separate phases. Ageing experiments indicate that the material retains substantial conductivity for at least a few years at room temperature.

Click chemistry is used to obtain new conductive polymer films based on poly(3,4-ethylenedioxythiophene) (PEDOT) from a new azide functional monomer. Postpolymerization, 1,3-dipolar cycloadditions in DMF, using a catalyst system of CuSO 4 and sodium ascorbate, and different alkynes are performed to functionalize films of PEDOT-N 3 and copolymers prepared from EDOT-N 3 and 3,4-ethylenedioxythiophene (EDOT). This approach enables new functionalities on PEDOT that could otherwise not withstand the polymerization conditions. Reactions on the thin polymer films have been optimized using an alkynated fluorophore, with reaction times of ∼20 h. The applicability of the method is illustrated by coupling of two other alkynes: a short chain fluorocarbon and a MPEG 5000 to the conductive polymer; this alters the advancing water contact angle of the surface by +20°and -20°/-25°, respectively. The targeted chemical surface modifications have been verified by X-ray photoelectron spectroscopy analysis.

In combination with various salts boric acid, B(OH) 3 , was shown to be an efficient, weak Lewis acid catalyst in the aqueous dehydration of fructose to 5-hydroxymethylfurfural (HMF) due to strong complexation between the boron atom and the hexoses. In the dehydration of a highly concentrated aqueous fructose solution (30 wt%), a HMF yield of 60% was achieved at 92% fructose conversion and a HMF selectivity of 65% with 100 g L -1 B(OH) 3 and 50 g L -1 sodium chloride in the aqueous phase and methyl-isobutylketone (MIBK) as extracting solvent. Furthermore, the dehydration of glucose resulted in a yield of 14% HMF at 41% glucose conversion after 5 h at similar conditions. These results are highly competitive with currently reported aqueous HMF dehydration systems. In combination with the non-corrosive and non-toxic nature of the boric acid, compared to other well known homogeneous catalysts applicable for the dehydration process (e.g., H 2 SO 4 and HCl), clearly, the boric acid-salt mixture is a very attractive catalyst system.

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Kristensen, Michael, Thomas Hansen, and Carsten Juel. Membrane proteins involved in potassium shifts during muscle activity and fatigue.

Conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization by “click chemistry” with high spatial resolution. Interdigitated microelectrodes prepared from an azide‐containing conducting polymer are selectively functionalized in sequence by two alkyne‐modified fluorophores by control of the applied potentials.

The analysis of Serratia liquefaciens MG1 luxAB insertion mutants that are responsive to N-butanoyl-Lhomoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible for the secretion of extracellular lipase, metalloprotease, and S-layer protein.Serratia liquefaciens MG1 employs a quorum-sensing system, the swr system, to control swarming motility. Swarming of S. liquefaciens MG1 is characterized by differentiation of short motile rods at the periphery of a colony into elongated, polyploid, and hyperflagellated swarm cells that migrate coordinately in rafts atop the agar surface (7, 9). The swr system relies on two proteins, SwrI, which directs the synthesis of the diffusable signal molecules N-butanoyl-L-homoserine lactone (C4-HSL) and N-hexanoyl-L-homoserine lactone in a molar ratio of 10 to 1, and SwrR, which, after binding of the signal molecules, is thought to activate or repress transcription of target genes (8,9,12). A global analysis by two-dimensional polyacrylamide gel electrophoresis (PAGE) revealed that at least 28 genes are under control of the swr regulatory system (12).By transposon mutagenesis, we have recently isolated 19 ЈluxAB insertion mutants of S. liquefaciens MG44 (swrI) that are responsive to the presence of C4-HSL (16). Only one of these mutants, S. liquefaciens PL10, was unable to form a swarming colony when C4-HSL was provided in the medium. This mutant was demonstrated to bear the insertion in a gene, swrA, which encodes an enzyme that catalyzes the synthesis of the biosurfactant serrawettin W2. This compound, a cyclic lipodepsipentapeptide carrying a 3-hydroxy C 10 fatty acid side chain, lowers the surface tension of the surrounding medium, a process that is indispensable for the development of an S. liquefaciens MG1 swarming colony. The swrA gene appears to be the only gene of the swr regulon that is required for swarming motility, since addition of purified serrawettin W2 to swarm plates fully restores swarming of the swrI mutant MG44 in the absence of C4-HSL. Thus, most of the quorum-sensingregulated genes in S. liquefaciens MG1 are involved in functions not related to swarming motility.In this report we show that one of the ЈluxAB insertion mutants which is responsive to the addition of C4-HSL bears the transposon insertion within the lipB gene, which encodes a component of the Lip exporter. This type I protein secretion system is responsible for the transport of the S. liquefaciens lipase, metalloprotease, and S-layer protein. As a consequence of the involvement of the swr system in the regulation of lipB expression, the levels of extracellular metalloprotease and Slayer protein are significantly lowered in a swrI mutant. However, the amount of secreted lipase is unchanged. Expression of the lipB gene is quorum sensing regulated. We previously noticed that the S. liquefaciens swrI mutant MG44 exhibits lower proteolytic activity than the wild-type MG1 (8). This sug...