Analytical in vitro approach for studying cyto- and genotoxic effects of particulate airborne material

In the field of inhalation toxicology, progress in the development of in vitro methods and efficient exposure strategies now offers the implementation of cellular-based systems. These can be used to analyze the hazardous potency of airborne substances like gases, particles, and complex mixtures (combustion products). In addition, the regulatory authorities require the integration of such approaches to reduce or replace animal experiments. Although the animal experiment currently still has to provide the last proof of the toxicological potency and classification of a certain compound, in vitro testing is gaining more and more importance in toxicological considerations. This paper gives a brief characterization of the CULTEX® Radial Flow System exposure device, which allows the exposure of cultivated cells as well as bacteria under reproducible and stable conditions for studying cellular and genotoxic effects after the exposure at the air–liquid or air–agar interface, respectively. A commercial bronchial epithelial cell line (16HBE14o-) as well as Salmonella typhimurium tester strains were exposed to smoke of different research and commercial available cigarettes. A dose-dependent reduction of cell viability was found in the case of 16HBE14o- cells; S. typhimurium responded with a dose-dependent induction of revertants. The promising results recommend the integration of cellular studies in the field of inhalation toxicology and their regulatory acceptance by advancing appropriate validation studies.     

Ion-molecule reactions of ammonia clusters with C60 aggregates embedded in helium droplets

Helium nanodroplets are co-doped with C(60) and ammonia. Mass spectra obtained by electron ionization reveal cations containing ammonia clusters complexed with up to four C(60) units. The high mass resolution of Δm/m≈ 1/6000 makes it possible to separate the contributions of protonated, unprotonated and dehydrogenated ammonia. C(60) aggregates suppress the proton-transfer reaction which usually favors the appearance of protonated ammonia cluster ions. Unprotonated C(x)(NH(3))(n)(+) ions (x = 60, 120, 180) exceed the abundance of the corresponding protonated ions if n < 5; for larger values of n the abundances of C(60)(NH(3))(n)(+) and C(60)(NH)(n-1)NH(4)(+) become about equal. Dehydrogenated C(60)NH(2)(+) ions are relatively abundant; their formation is attributed to a transient doubly charged C(60)-ammonia complex which forms either by an Auger process or by Penning ionization following charge transfer between the primary He(+) ion and C(60). The abundance of C(x)NH(3)(+) and C(x)NH(4)(+) ions (x = 120 or 180) is one to two orders of magnitude weaker than the abundance of ions containing one or two additional ammonia molecules. However, a model involving evaporation of NH(3) or NH(4) from the presumably weakly bound C(x)NH(3)(+) and C(x)NH(4)(+) ions is at odds with the lack of enhancement in the abundance of C(120)(+) and C(180)(+). Mass spectra of C(60) dimers complexed with water complement a previous study of C(60)(H(2)O)(n)(+) recorded at much lower mass resolution.     

Simulation of Surface Wetting by Droplets Using a Phase Field Model

In the proposed phase field model a continuous order parameter indicates the phase distribution (liquid/gas). An energy density functional which is dependent on the surface tensions and defined by three contributions yields the total energy of the system. An equilibrium state is then computed by minimizing this energy of the system using an evolution equation. Details of the algorithmic implementation are discussed by illustrative examples. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Advances in Trifluoromethylating Phosphorus Compounds

Abstract

The System CF₃I/Me₃P is re-investigated and Me₂PCF₃, Me₄P⁺γ, (CF₃)₂PMe₃, Me₃PI₂, [Me₃(CF₃)P]⁺γ are found as products. Using CF₃Br/P(NEt₂)₃ the phosphines R¹ ₂PCF₃ and R¹P(CF₃)₂ (e.g. R¹ = Me, iPr, NEt₂) can be obtained which are precursors either for phosphoranes (e.g. 1,2λ⁵σ⁵-oxaphosphetanes) or phosphonium salts (e.g. [R¹ ₂(Me)PCF₃]⁺X^? or [R¹(Me)P(CF₃)₂X^?]. The latter are deprotonated to furnish methylene phosphoranes R¹ ₂(CH₂=)PCF₃ or R¹(CH₂=)P(CF₃)₂, reactive synthons. From CF₃Br/P(NEt₂)₃/P(OPh)₃ the phosphine P(CF₃)₃ is available, which turned out to be a potent electrophile. Amido phospites ROP(NEt₂)₂ and halides R²X (R²=CCl₂CF₃, X=Cl; R²=CF=CFCF₃, X=F; R²=C₆F₅, X=Br, I; R²=C(CF₃)₃, X=Br; R²=SCF₃, X=CF₃) undergo an ARBUZOV reaction.     

Electrospinning of polyesteramides based on ε-caprolactam and ε-caprolactone from solution

The paper is focused on the preparation of nanofiber layers of polyesteramides with various ratios of ε-caprolactam/ε-caprolactone structural units. We have studied the effect of the system parameters, i.e., the composition of the copolymer, its molar mass and the concentration of the solution on morphology of fiber layers being formed during the electrostatic wet spinning. The process parameters were constant during the processing. Morphology of the fiber layers is given by the composition of the copolymer, i.e., by its polarity, the content of the crystalline phase and thus its separation in the process of evaporating the solvent. Fibers with diameters ranging from 100 to 160 nm were obtained for polyesteramides containing 20 or 40 mol% lactone units during optimizing the system parameters, i.e., the concentration of the solution and molar mass of polyesteramide.     

High resolution characterization of uranium in sediments by DGT and DET techniques ACA-S-12-2197

Diffusive equilibrium (DET) and diffusive gradient in thin film (DGT) techniques with an inductively coupled plasma mass spectrometry detection of elements were applied to characterize uranium, manganese, iron and ²³⁸U/²³⁵U isotopic ratio depth profiles in sediment pore water at high spatial resolution and to monitor uranium uptake/remobilization processes in uranium spiked sediment core samples under laboratory, well controlled conditions. Modified constrained sediment DGT probes, packed with Spheron-Oxin^® resin gel, were employed for selective uranium measurements. Spatially resolved DET and DGT responses were indicative of local redistribution of uranium in naturally uranium poor and rich sediments.     

Analysis of human blood plasma and hen egg white by chiroptical spectroscopic methods (ECD, VCD, ROA)

Chiroptical methods are widely used in structural and conformational analyses of biopolymers. The application of these methods to investigations of biofluids would provide new avenues for the molecular diagnosis of protein-misfolding diseases. In this work, samples of human blood plasma and hen egg white were analyzed using a combination of conventional and chiroptical methods: ultraviolet absorption/electronic circular dichroism (UV/ECD), Fourier transform infrared absorption/vibrational circular dichroism (FTIR/VCD), and Raman scattering/Raman optical activity (Raman/ROA). For comparison, the main components of these substances—human serum albumin (HSA) and ovalbumin (Ova)—were also analyzed by these methods. The ultraviolet region of the ECD spectrum was analyzed using the CDNN CD software package to evaluate the secondary structures of the proteins. The UV/ECD, FTIR/VCD, and Raman/ROA spectra of the substances were quite similar to those of the corresponding major proteins, while some differences were also detected and explained. The conclusions drawn from the FTIR/VCD and Raman/ROA data were in good agreement with the secondary structures calculated from ECD. The results obtained in this work demonstrate that the chiroptical methods used here can be applied to analyze not only pure protein solutions but also more complex systems, such as biological fluids.

Detection of homogeneous distribution of functional groups in mesoporous silica by small angle neutron scattering and in situ adsorption of nitrogen or water

The distribution of SO(3)H-functional groups attached to the ordered inner pore walls of mesoporous Si-MCM-41 materials based on SiO(2) was investigated by gas adsorption combined with in situ small angle neutron scattering (SANS). The functionalization was performed by two different methods, (i) grafting and (ii) co-condensation. The adsorbates N(2) at 77 K or a H(2)O/D(2)O mixture of 42:58 at 298 K possess neutron scattering length densities (SLD) similar to that of SiO(2) and therefore quench the diffraction signals of the nonmodified silica. SANS measurements show that N(2) matches completely not only with the pristine mesoporous Si-MCM-41 but also with Si-MCM-41-SO(3)H functionalized by grafting. Thus, full access of adsorbate into the entire length of the pores is proven. For the analysis of the distribution of functional groups within the pores in dependence on the used functionalization method, grafting or co-condensation, however, the more specific adsorbate H(2)O/D(2)O (42:58) is necessary, because it reacts more sensitively toward small changes in the SLD of the host material. For grafted Si-MCM-41-SO(3)H materials, an incomplete quenching was observed, indicating that only some regions, probably the pore mouths, have been modified. For a sample functionalized by co-condensation, almost no quenching of the neutron diffraction was found, indicating a very homogeneous distribution of the functional groups along the entire pores.     

Study of electrochemical oxidation of cyanidin glycosides by online combination of electrochemistry with electrospray ionization tandem mass spectrometry

Abstract  

Electrochemistry coupled with mass spectrometry (EC–MS) is a promising analytical tool for the online study of oxidation processes of anthocyanins. Two cyanidin glycosides, cyanidin-3-galactoside (ideain) and cyanidin-3,5-diglucoside (cyanin), were subjected to electrochemical oxidation and subsequent online mass spectrometric identification of the formed products. Application of relatively low working potentials (around 100 mV vs. Pd/H₂) using a porous graphite coulometric electrode yielded detectable oxidation products. As determined by hydrodynamic voltammetry, the monoglycosylated analogue undergoes anodic oxidation easier than the diglycosylated one. As a first step of the electrochemically induced oxidation, incorporation of a hydroxyl group was observed for both glycosides. Besides, an oxidative condensation of two anthocyanin molecules was observed. The proposed oxidative condensation was further confirmed by consecutive fragmentation (i.e., collection of MS², MS³, and MS⁴ spectra) in which corresponding subsequent losses of the sugar moiety were observed.     

Synthesis, spectroscopic properties, and electropolymerization of azulene dyads

Four azulene dyads have been synthesized and studied by spectroscopic and electrochemical methods. A triarylamine, a boron-dipyrromethene (BDP or BODIPY), a porphyrin, and an isoalloxazine moiety have been linked to an extended π electron system at the 2-position of azulene, leading to the dyads 1-4, respectively. For the synthesis of 1-4, first 2-(4-ethynyl-phenyl)azulene (EPA) was prepared, which was further reacted with the halogenated chromophores by Pd-catalyzed cross-coupling reactions. The dyads 1-4 exhibit strong absorption bands in the visible range, which are dominated by the absorption spectra of the individual subchromophores. Fluorometric studies of 2-4 revealed that after excitation of the subchromophoric unit attached to the parent azulene moiety, quenching mainly through energy transfer to azulene is effective, whereas possible charge-transfer interactions play only a minor role. Potentiodynamic oxidation of the dyads 1-4 leads to the formation of polymer films, which are deposited at the electrode. The polymer film derived from 1 was further characterized by spectroelectrochemistry. During positive doping of poly-1, a strong absorption band appears at 13,200 cm(-1), which is typical for triarylamine radical cations. This band is overlapping with a broad absorption band in the low-energy region that might be caused by charge-transfer interactions within the polymer.