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Tomographic volumetric printing (TVP) is considered as a fast and auxiliary-free 3D printing technique, but control of internal mechanical properties remains less investigated for TVP. Here, the authors show that wavelength-sensitive photoresins can be cured using visible and UV sources simultaneously in a TVP setup to generate internal mechanical property gradients with high precision.

In our efforts to design an optical sensor for hydrogen peroxide, we have realized the importance of knowing/controlling the diffusion of hydrogen peroxide to the indicator, especially in the case of an irreversible indicator. Since we found little literature data, we decided to test the permeability of hydrogen peroxide in commercially available polymers, focusing on the polyurethanes HydroMed™ and HydroThane™, which are commonly used for immobilization matrices in optical sensors. Measured values are between 5.12 10−9 ± 8.50 10−10 and 2.25 10−6 ± 1.00 10−7 cm2 s−1. Keywords: Hydrogen peroxide, Polymer membrane, Permeability, Diffusivity

We study the relaxation of linear polymer molecules following fast uniaxial extension. Polystyrene melts of M_{w}=80 kg/mol are elongated at a Rouse-Weissenberg number Wi_{R}=1.5 to Hencky strain ɛ=3, where steady state is approached using a filament stretch rheometer. Samples were quenched for different duration of stress relaxation at constant Hencky strain to preserve molecular conformation by rapid cooling below the glass transition temperature. Expansion of ex situ small-angle neutron-scattering data in spherical harmonics shows experimental evidence for the decoupling of local and global relaxation phenomena from highly stretched states. This work demonstrates both that the decoupling can be seen in the spherical harmonics expansion and that it can be seen even for short chains provided the initial state is highly oriented.

Lung infections with Pseudomonas aeruginosa (PA) is the most common cause of morbidity and mortality in cystic fibrosis (CF) patients. Due to its ready adaptation to the dehydrated mucosa of CF airways, PA infections tend to become chronic, eventually killing the patient. Hydrogen cyanide (HCN) at ppb level has been reported to be a PA biomarker. For early PA detection in CF children not yet chronically lung infected a non-invasive Surface-Enhanced Raman Spectroscopy (SERS)-based breath nanosensor is being developed. The triple bond between C and N in cyanide, with its characteristic band at ∼2133 cm−1, is an excellent case for the SERS-based detection due to the infrequent occurrence of triple bonds in nature. For demonstration of direct HCN detection in the gas phase, a gold-coated silicon nanopillar substrate was exposed to 5 ppm HCN in N2. Results showed that HCN adsorbed on the SERS substrate can be consistently detected under different experimental conditions and up to 9 days after exposure. For detection of lower cyanide concentrations serial dilution experiments using potassium cyanide (KCN) demonstrated cyanide quantification down to 1 μM in solution (corresponding to 18 ppb). Lower KCN concentrations of 10 and 100 nM (corresponding to 0.18 and 1.8 ppb) produced SERS intensities that were relatively similar to the reference signal. Since HCN concentration in the breath of PA colonized CF children is reported to be ∼13.5 ppb, the detection of cyanide is within the required range. Keywords: Surface-Enhanced Raman Spectroscopy, Hydrogen cyanide, Pseudomonas aeruginosa, Cystic fibrosis, Breath analysis

In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes.

Metaphase chromosome spreading is the most crucial step required for successful karyotyping and FISH analysis. These two techniques are routinely used in cytogenetics to assess the chromosome abnormalities. The spreading process has been studied for years but it is still considered an art more than a science. The chromosome spreading greatly depends on the environmental conditions such as humidity and temperature, which govern the evaporation of fixative, in which the cells are suspended. The spreading is normally performed manually in ambient conditions on glass slides, which are hydrophilic, and thus allow for better quality spreads. Further cytogenetic analysis depends on the quality of the spreads, which is dependent on the skills of the personnel and is thus limited to laboratory settings. Here, we present a semi-closed microfluidic chip for preparation of the metaphase spreads on a glass and a Topasr substrate rendered more hydrophilic by oxygen plasma treatment coupled with photografting. The device consists of a microfluidic chamber with perfusion holes that facilitate the evaporation of fixative and reliable formation of the spreads. The usability of the chromosome spreads formed on the glass and the Topasr slide is tested by performing FISH analysis.