The oxidation of bitumen witnessed in-situ by infrared spectroscopy

During the production and recycling of asphalt concrete, bitumen in contact with inorganic particles is exposed to air at high temperatures. As a result an oxidation of bitumen, also known as aging, occurs. The reaction between bitumen and air at 163 °C was studied insitu with and without the presence of inorganic impurities by means of fourier transform infrared spectroscopy in the attenuated reflectance mode. This oxidation was discovered to be a step-wise reaction facilitated by the oxidation of thiols and creation of peroxides within the system. The rate of reaction was demonstrated to depend on the type of impurity present, of which iron (III) chloride was the strongest catalyst. It was further demonstrated that the oxidation reaction is inhibited by the adsorption of thiol species present in the system on copper particles. Combining copper with the iron (III) chloride-containing system also resulted in the inhibition of signal increase in the sulfoxide region of the spectra. The results of this preliminary research on the bitumen oxidation reaction presented are proposed for further research regarding control of aging of asphalt concrete, especially during the recycling works.     

Food colors: Existing and emerging food safety concerns

Food colors are added to different types of commodities to increase their visual attractiveness or to compensate for natural color variations. The use of these additives is strictly regulated in the European Union, the United States, and many other countries worldwide. There is a growing concern about the safety of some commonly used legal food colorants and there is a trend to replace the synthetic forms with natural products. Additionally, a number of dyes with known or suspected genotoxic or carcinogenic properties have been shown to be added illegally to foods. Robust monitoring programs based on reliable detection methods are required to assure the food is free from harmful colors. The aim of this review is to present an up to date status of the various concerns arising from use of color additives in food. The most important food safety concerns in the field of food colors are lack of uniform regulation concerning legal food colors worldwide, possible link of artificial colors to hyperactive behavior, replacement of synthetic colors with natural ones, and the presence of harmful illegal dyes—both known but also new, emerging ones in food. The legal status of food color additives in the EU, United States, and worldwide is summarized. The reported negative health effects of both legal and illegal colors are presented. The European Rapid Alert System for Food and Feed notifications and US import alerts concerning food colors are analyzed and trends in fraudulent use of color additives identified. The detection methods for synthetic colors are also reviewed.     

Octanoic Acid—An Insecticidal Metabolite of Conidiobolus coronatus (Entomopthorales) That Affects Two Majors Antifungal Protection Systems in Galleria mellonella (Lepidoptera): Cuticular Lipids and Hemocytes

The food flavour additive octanoic acid (C8:0) is also a metabolite of the entomopathogenic fungus Conidiobolus coronatus, which efficiently infects and rapidly kills Galleria mellonella. GC-MS analysis confirmed the presence of C8:0 in insecticidal fraction FR3 extracted from C. coronatus filtrate. Topical administration of C8:0 had a dose-dependent effect on survival rates of larvae but not on pupation or adult eclosion times of the survivors. Topically applied C8:0 was more toxic to adults than larvae (LD100 for adults 18.33 ± 2.49 vs. 33.56 ± 2.57 µg/mg of body mass for larvae). The administration of C8:0 on the cuticle of larvae and adults, in amounts corresponding to their LD50 and LD100 doses, had a considerable impact on the two main defense systems engaged in protecting against pathogens, causing serious changes in the developmental-stage-specific profiles of free fatty acids (FFAs) covering the cuticle of larvae and adults and damaging larval hemocytes. In vitro cultures of G. mellonella hemocytes, either directly treated with C8:0 or taken from C8:0 treated larvae, revealed deformation of hemocytes, disordered networking, late apoptosis, and necrosis, as well as caspase 1–9 activation and elevation of 8-OHdG level. C8:0 was also confirmed to have a cytotoxic effect on the SF-9 insect cell line, as determined by WST-1 and LDH tests.     

Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing

At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs), is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, a series of core@shell NaYF₄ UCNPs doped with Yb³⁺ and Ho³⁺ ions are presented here, where the same dopant concentrations are distributed in different particle architectures following the scheme: YbHo core and YbHo@…, …@YbHo, Yb@Ho, Ho@Yb, YbHo@Yb, and Yb@YbHo core–shell NPs. As revealed by quantitative steady‐state and time‐resolved luminescence studies, the relative spatial distribution of the A and S ions in the UCNPs and their protection from surface quenching has a critical impact on their luminescence characteristics. Although the increased amount of Yb³⁺ ions boosts UCNP performance by amplifying the absorption, the Yb³⁺ ions can also efficiently dissipate the energy stored in the material through energy migration to the surface, thereby reducing the overall energy transfer efficiency to the activator ions. The results provide yet another proof that UC phosphor chemistry combined with materials engineering through intentional core@shell structures may help to fine‐tune the luminescence features of UCNPs for their specific future applications in biosensing, bioimaging, photovoltaics, and display technologies.     

Verification of the effectiveness of SCAR (sequence characterized amplified region) primers for the identification of Polish strains of Fusarium culmorum and their potential ability to produce B-trichothecenes and zearalenone

Rapid and sensitive methods to detect Fusarium culmorum and trichothecene and zearalenone producing strains in food and feed are valuable in predicting potential contamination. In this study the effectiveness of primers, recommended in the literature, for species identification of F. culmorum and basic genes encoding for mycotoxin production was tested. A total of 68 isolates of F. culmorum were collected from cereals and potato between 2005 and 2008 from different Polish provinces. It was shown that from among the four primer pairs enabling the identification of F. culmorum, and therefore also to establish its presence in the material, only primers Fc01F/Fc01R seem to be fully effective in the case of Polish strains. Determination of material contamination by F. culmorum, however, is only a first step in determining food safety. It is also extremely important to identify genes encoding the potential ability to produce mycotoxins. It was shown that three pairs of primers (tox5-1/tox5-2, HATriF/HATriR and Tri5F/Tri5R) enable a fully effective identification of the presence of the Tri5 gene responsible for producing trichothecenes. Determination of the DON-chemotype, and thus identification of the strains of F. culmorum potentially producing deoxynivalenol, is enabled equally by MinusTri7F/MinusTri7F, Tri7F/Tri7DON and Tri13F/Tri13DONR. However, a determination of the NIV-chemotype, and thus identification of the strains potentially producing nivalenol, is enabled by Tri7F/Tri7R, Tri7F/Tri7NIV and Tri13NIVF/Tri13R. The potential ability of isolates to produce ZEA can be determined to the same degree in assay with PKS4-PS.1/PKS4-PS.2 and F1/R1.     

Comparison of the first stage of the thermal decomposition of Polish coals by diffuse reflectance infrared spectroscopy

Diffuse reflectance Fourier transform infrared spectroscopy was applied to study the decomposition of hard and brown coal during mild pyrolysis. The pyrolysis of investigated samples was conducted with a heating rate of 10 K/min up to 673 K under ambient pressure and a nitrogen flow of 4 L/h. Curve-fitting analysis was employed to characterise the coal structures evolving in temperatures ranging from 323 to 673 K. This study gives the information about the degradation of hydrogen bonds and oxygen structure. The comparison of the calculated structural parameters shows that bonds assigned to C_ar in hard coal are more stable at the investigated temperature range than the bonds in brown coal. The same phenomenon was observed for the CH bonds in aromatic formations. It was noted that during the pyrolysis the first changes in the structural parameters of lignite are visible at temperatures above 423 K and in case of hard coal above 473 K.     

Phase transfer catalysed alkylation of enamines of β-keto carbothionic acid anilides with dihalogenoalkanes: Synthesis of Cyclic S,N-Acetals of α-Oxo Ketene

Alkylation of 2-morpholino-cycloalken-1-carbothionic acid anilides 1 and 2 with 1,3-dibromopropane in a two-phase system leads to 1-morpholino-cycloalken-3-aryl-tetrahydro-1,3-thiazine-2-ylidene 3 and 4 . Reactions of 2-morpholino-cyclopenten-1-carbothionic acid anilides 5 and 3-morpholinothiocinnamic acid anilides 8 with 1,2-dibromoethane yield 1-morpholino-cyclopenten-3-aryl-thiazolidine-2-ylidene 7 and 2-(2′-phenyl-2′-oxo-ethylidene-3-aryl)thiazolidine 9 , respectively. Alkylation of 1-indanone- and 1-tetralone-2-carbothionic acid anilides 11 and 12 with dihalogenoalkanes yield 1-oxo-indanylidene- and 1-oxo-tetralidenethiazolidines 14 , 16 and tetrahydro-1,3-thiazines 15 , 17 , respectively.