Streptavidin Homologues for Applications on Solid Surfaces at High Temperatures.

One of the most commonly used bonds between two biomolecules is the bond between biotin and streptavidin (SA) or streptavidin homologues (SAHs). A high dissociation constant and the consequent high-temperature stability even allows for its use in nucleic acid detection under polymerase chain reaction (PCR) conditions. There are a number of SAHs available, and for assay design, it is of great interest to determine as to which SAH will perform the best under assay conditions.

Correction approach of detector backlighting in radiography.

In various kinds of radiography, deficient transmission imaging may occur due to backlighting inside the detector itself arising from light or radiation scattering. The related intensity mismatches barely disturb the high resolution contrast, but its long range nature results in reduced attenuation levels which are often disregarded. Based on X-ray observations and an empirical formalism, a procedure is developed for a first order correction of detector backlighting.

Length and Energy Dependence of Low-Energy Electron-Induced Strand Breaks in Poly(A) DNA.

The DNA in living cells can be effectively damaged by high-energy radiation, which can lead to cell death. Through the ionization of water molecules, highly reactive secondary species such as low-energy electrons (LEEs) with the most probable energy around 10 eV are generated, which are able to induce DNA strand breaks via dissociative electron attachment. Absolute DNA strand break cross sections of specific DNA sequences can be efficiently determined using DNA origami nanostructures as platforms exposing the target sequences towards LEEs.

Lanthanide Luminescence Revealing the Phase Composition in Hydrating Cementitious Systems.

The hydration process of Portland cement in a cementitious system is crucial for development of the high-quality cement-based construction material. Complementary experiments of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and time-resolved laser fluorescence spectroscopy (TRLFS) using europium (Eu(III)) as an optical probe are used to analyse the hydration process of two cement systems in the absence and presence of different organic admixtures. We show that different analysed admixtures and the used sulphate carriers in each cement system have a significant influence on the hydration process, namely on the time-dependence in the formation of different hydrate phases of cement.

A Mechanistic Perspective on Plastically Flexible Coordination Polymers.

Mechanical flexibility in single crystals of covalently bound materials is a fascinating and poorly understood phenomenon. We present here the first example of a plastically flexible one-dimensional (1D) coordination polymer. The compound [Zn(μ-Cl) (3,5-dichloropyridine) ] is flexible over two crystallographic faces.

Legal situation and current practice of waste incineration bottom ash utilisation in Europe.

Almost 500 municipal solid waste incineration plants in the EU, Norway and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals.

Structure/property relationship of polyvinyl alcohol/dimethoxydimethylsilane composite membrane: Experimental and theoretical studies.

A novel mixed matrix composite has been prepared using solution-casting method at different volume concentrations of polyvinyl alcohol; PVA (50, 67, 75 and 80%) and fixed amount of dimethoxydimethylsilane in air atmosphere. The hydrolyzed dimethyldisilanol acts as in-situ cross linker through a wet-out condensation between the hydroxyl moieties of Si and PVA. Such process improves the mechanical properties of composite membranes as compared to pristine PVA which has been determined as function of varied membrane components to evaluate the structure/property relationships.

Eco-friendly synthesis of recyclable mesoporous zinc ferrite@reduced graphene oxide nanocomposite for efficient photocatalytic dye degradation under solar radiation.

Zinc ferrite and graphene composites have attracted considerable attention in wastewater treatment. In this work, a magnetically separable mesoporous composite of ZnFeO nanoparticles (NPs) and reduced graphene oxide (rGO) was prepared through a simple and eco-friendly method with pure water as solvent and without the need for subsequent thermal treatment. Uniformly dispersed ZnFeO NPs on the surface of rGO sheets exhibited good crystallinity and a large BET specific surface area.

Evolution of Termite Symbiosis Informed by Transcriptome-Based Phylogenies.

Termitidae comprises ∼80% of all termite species [1] that play dominant decomposer roles in tropical ecosystems [2, 3]. Two major events during termite evolution were the loss of cellulolytic gut protozoans in the ancestor of Termitidae and the subsequent gain in the termitid subfamily Macrotermitinae of fungal symbionts cultivated externally in "combs" constructed within the nest [4, 5]. How these symbiotic transitions occurred remains unresolved.

Author Correction: A proofreading-impaired herpesvirus generates populations with quasispecies-like structure.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A proofreading-impaired herpesvirus generates populations with quasispecies-like structure.

RNA virus populations are composed of highly diverse individuals that form a cloud of related sequences commonly referred to as a 'quasispecies'. This diversity arises as a consequence of low-fidelity genome replication. By contrast, DNA virus populations contain more uniform individuals with similar fitness.

Manipulating the dynamics of mechanochemical ternary cocrystal formation.

The mechanism of ternary cocrystal formation, and the potential role of intermediate binary phases, has been debated for some time. We report here the first in situ real-time monitoring of two prototypic ternary cocrystals. Our results suggest that the question is more complicated than previously considered.

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions.

We here explore how ball-mill-grinding frequency affects the kinetics of a disulfide exchange reaction. Our kinetic data show that the reaction progress is similar at all the frequencies studied (15-30 Hz), including a significant induction time before the nucleation and growth process starts. This indicates that to start the reaction an initial energy accumulation is necessary.

Yb,Nd,Er-doped upconversion nanoparticles: 980 nm versus 808 nm excitation.

Yb,Nd,Er-doped upconversion nanoparticles (UCNPs) have attracted considerable interest as luminescent reporters for bioimaging, sensing, energy conversion/shaping, and anticounterfeiting due to their capability to convert multiple near-infrared (NIR) photons into shorter wavelength ultraviolet, visible or NIR luminescence by successive absorption of two or more NIR photons. This enables optical measurements in complex media with very little background and high penetration depths for bioimaging. The use of Nd as substitute for the commonly employed sensitizer Yb or in combination with Yb shifts the excitation wavelength from about 980 nm, where the absorption of water can weaken upconversion luminescence, to about 800 nm, and laser-induced local overheating effects in cells, tissue, and live animal studies can be minimized.

Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures.

Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths.

High photoluminescence of shortwave infrared-emitting anisotropic surface charged gold nanoclusters.

Incorporating anisotropic surface charges on atomically precise gold nanoclusters (Au NCs) led to a strong absorption in the near-infrared region and could enable the formation of self-assembled Au NCs exhibiting an intense absorption band at ∼1000 nm. This surface modification showed a striking enhancement of the photoluminescence in the Shortwave Infrared (SWIR) region with a quantum yield as high as 6.1% in water.

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation.

The transformation of a base-catalyzed, mechano-assisted Knoevenagel condensation of mono-fluorinated benzaldehyde derivatives (-, -, -benzaldehyde) with malonodinitrile was investigated in situ and in real time. Upon milling, the -substituted product was found to crystallize initially into two different polymorphic forms, depending on the quantity of catalyst used. For low catalyst concentrations, a mechanically metastable phase (monoclinic) was initially formed, converting to the mechanically stable phase (triclinic) upon further grinding.

Simple Self-Referenced Luminescent pH Sensors Based on Upconversion Nanocrystals and pH-Sensitive Fluorescent BODIPY Dyes.

We present the design and fabrication of pH responsive ratiometric dual component sensor systems based on multicolor emissive upconversion nanoparticles (UCNP) and pH sensitive BODIPY dyes with tunable p K values embedded into a polymeric hydrogel matrix. The use of NIR excitable NaYF:Yb,Tm UCNPs enables background free read-out. Furthermore, the spectrally matching optical properties of the UCNPs and the dyes allow the UCNPs to serve as excitation light source for the analyte-responsive BODIPY as well as intrinsic reference.

Assessment of leachates from reactive fire-retardant coatings by chemical analysis and ecotoxicity testing.

The environmental compatibility of reactive fire-retardant coatings (intumescent paints) was investigated by a combination of leaching and ecotoxicological tests. Three representative fire-retardant coating systems were tested using two leaching procedures: "Horizontal Dynamic Surface Leaching Test" (DSLT) and the "Intermittent Immersion Test" (IIT). All eluate fractions (8 for DSLT and 9 for IIT) were analyzed for pH, conductivity, concentration of total organic carbon and selected anions und cations.

A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads.

The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays.

Simulating Fiber-Reinforced Concrete Mechanical Performance Using CT-Based Fiber Orientation Data.

The main hindrance to realistic models of fiber-reinforced concrete (FRC) is the local materials property variation, which does not yet reliably allow simulations at the structural level. The idea presented in this paper makes use of an existing constitutive model, but resolves the problem of localized material variation through X-ray computed tomography (CT)-based pre-processing. First, a three-point bending test of a notched beam is considered, where pre-test fiber orientations are measured using CT.

Electron-Induced Reactions in 3-Bromopyruvic Acid.

3-Bromopyruvic acid (3BP) is a potential anti-cancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of cancer therapy.

Defect ferromagnetism in SnO:Zn hierarchical nanostructures: correlation between structural, electronic and magnetic properties.

We report on the ferromagnetism of Sn Zn O ( ≤ 0.1) hierarchical nanostructures with various morphologies synthesized by a solvothermal route. A room temperature ferromagnetic and paramagnetic response was observed for all compositions, with a maximum in ferromagnetism for = 0.

Colour-optimized quantum yields of Yb, Tm Co-doped upconversion nanocrystals.

We present here a systematic analysis of the influence of Tm doping concentrations (x ) on the excitation power (P)-dependent upconversion luminescence and -performance of hexagonal-phase NaYF: 20% Yb, x % Tm upconversion nanoparticles (UCNPs) for x of 0.2, 0.5, 0.

Theoretical and numerical study on ignition behaviour of coal dust layers on a hot surface with corrected kinetic parameters.

Industrial fires and explosions initiating from self-ignition of combustible porous dust deposits represent a serious hazard for human beings, environment and industry. Understanding the fundamental basis of combustible dust ignition behaviours at different geometries is of importance to prevent and mitigate the accidental risks. A correlation of self-ignition temperatures (SITs) measured by hot-oven tests and minimum ignition temperatures of dust layers (MITLs) determined by hot-plate tests has been established previously.