Enhancing the blood compatibility of ion-selective electrodes

In vivo monitoring of various analytes is important for many bioanalytical and biomedical applications. The crucial challenge in this type of applications is the interaction of the sensor with the host environment, which is qualitatively described by the term biocompatibility. This review discusses recent advances in methods and materials used for the improvement of the biocompatibility of ion-selective electrodes especially as it relates to their interaction with blood components.     

Generation of Oxidoreductases with Dual Alcohol Dehydrogenase and Amine Dehydrogenase Activity

The l -lysine-ϵ-dehydrogenase (LysEDH) from Geobacillus stearothermophilus naturally catalyzes the oxidative deamination of the ϵ-amino group of l -lysine. We previously engineered this enzyme to create amine dehydrogenase (AmDH) variants that possess a new hydrophobic cavity in their active site such that aromatic ketones can bind and be converted into α-chiral amines with excellent enantioselectivity. We also recently observed that LysEDH was capable of reducing aromatic aldehydes into primary alcohols. Herein, we harnessed the promiscuous alcohol dehydrogenase (ADH) activity of LysEDH to create new variants that exhibited enhanced catalytic activity for the reduction of substituted benzaldehydes and arylaliphatic aldehydes to primary alcohols. Notably, these novel engineered dehydrogenases also catalyzed the reductive amination of a variety of aldehydes and ketones with excellent enantioselectivity, thus exhibiting a dual AmDH/ADH activity. We envisioned that the catalytic bi-functionality of these enzymes could be applied for the direct conversion of alcohols into amines. As a proof-of-principle, we performed an unprecedented one-pot “hydrogen-borrowing” cascade to convert benzyl alcohol to benzylamine using a single enzyme. Conducting the same biocatalytic cascade in the presence of cofactor recycling enzymes (i.e., NADH-oxidase and formate dehydrogenase) increased the reaction yields. In summary, this work provides the first examples of enzymes showing “alcohol aminase” activity.     

Synthesis and Optical Properties on a Series of Polyethers Incorporating Terfluorene Segments and Methylene Spacers

A series of polyethers consisting of a modified terfluorenediol connected with a nonconjugated spacer were synthesized and characterized in respect to their thermal, electrochemical, optical and morphological properties. The polymers were further investigated as thin deposits with the use of the FT‐IR technique after thermal (200°C for 30 min) and photo‐oxidation treatment. After thermal treatment no generation of the carbonyl stretching mode of the fluorenone moiety is observed, while after photo‐oxidation in various times (between 5 to 30 min) the appearance of the fluorenone unit is well established. Furthermore, the length of the flexible spacer used influenced the optical properties of the polyethers after thermal treatment. In particular, odd ones showed more intensely the low energy emission band at 520 nm after the thermal treatment in contrast to even ones.     

Selective plane illumination optical and optoacoustic microscopy for postembryonic imaging

Intravital imaging of large specimens is intrinsically challenging for postembryonic studies. Selective plane illumination microscopy (SPIM) has been introduced to volumetrically visualize organisms used in developmental biology and experimental genetics. Ideally suited for imaging transparent samples, SPIM can offer high frame rate imaging with optical microscopy resolutions and low phototoxicity. However, its performance quickly deteriorates when applied to opaque tissues. To overcome this limitation, SPIM optics were merged with optical and optoacoustic (photoacoustic) readouts. The performance of this hybrid imaging system was characterized using various phantoms and by imaging a highly scattering ex vivo juvenile zebrafish. The results revealed the system's enhanced capability over that of conventional SPIM for high‐resolution imaging over extended depths of scattering content. The approach described here may enable future visualization of organisms throughout their entire development, encompassing regimes in which the tissue may become opaque.

     

Singular Integrals on Ahlfors-David Regular Subsets of the Heisenberg Group

We investigate certain singular integral operators with Riesz-type kernels on s-dimensional Ahlfors-David regular subsets of Heisenberg groups. We show that L ²-boundedness, and even a little less, implies that s must be an integer and the set can be approximated at some arbitrarily small scales by homogeneous subgroups. It follows that the operators cannot be bounded on many self-similar fractal subsets of Heisenberg groups.     

New rod-coil block copolymers consisting of terfluorene segments and electron transporting units as the flexible blocks

A series of new rod-coil block copolymers having a well-defined terfluorene unit as the rigid segment with three different electron transporting moieties as the flexible part, such as side chain oxadiazole (TFPOXD), side chain quinoline (TFPQN) and a molecule containing two oxadiazole rings in the side chain (TFPDOXD), were synthesized using the atom transfer radical polymerization (ATRP) technique. All the synthesized copolymers were extensively examined with respect to their optical properties as pristine films, upon thermal annealing (200 °C for 30 min in air) and photo-oxidation treatment in air. Thermal annealing of the block copolymers resulted in stable blue light emission from TFPOXD and TFPDOXD while TFPQN showed the appearance of the undesired 520 nm emission band. In addition, TFPOXD does not exhibit the low-energy emission band at 520 nm after photo-oxidation under prolonged diffuse UV radiation at ambient atmosphere, despite the fluorenone formation on the terfluorene segment, in contrast to all the other copolymers.     

Erratum: A life cycle framework for the investigation of environmentally benign nanoparticles and products [Phys. Status Solidi RRL 5, No. 9, 312–317 (2011)]

The name of a further author and contributor to this work, Roland Clift , has been added to the author list of the article in agreement with all co‐authors. It had been inadvertently omitted from the original version of the paper (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ergodicity of Markov Semigroups with H?rmander Type Generators in Infinite Dimensions

We develop an effective strategy for proving strong ergodicity of (nonsymmetric) Markov semigroups associated to H?rmander type generators when the underlying configuration space is infinite dimensional.