A 4-year study of bovine reproductive hormones that are induced by pharmaceuticals and appear as steroid estrogenic pollutants in the resulting slurry, using in vitro and instrumental analytical methods.

The main objective of the research was to study the environmental "price" of the large-scale, milk production from a rarely known perspective, from the mapping of the estrogenic footprint (the amount of oestrus-inducer hormonal products, and the generated endoestrogens) in the resulting slurry in a dairy cow farm. These micropollutants are endocrine-disrupting chemicals (EDCs) and can be dangerous to the normal reproductive functions even at ng/kg concentration. One of them, 17ß-estradiol, has a 20,000 times stronger estrogenic effect than bisphenol-A, a widely known EDC of industrial origin. While most studies on EDCs are short-term and/or laboratory based, this study is longitudinal and field-based. We sampled the slurry pool on a quarterly basis between 2017 and 2020. Our purpose was testing the estrogenic effects using a dual approach. As an effect-based, holistic method, we developed and used the YES (yeast estrogen screen) test employing the genetically modified Saccharomyces cerevisiae BJ3505 strain which contains human estrogenic receptor. For testing exact molecules, UHPLC-FLD was used. Our study points out that slurry contains a growing amount of EDCs with the risk of penetrating into the soil, crops and the food chain. Considering the Green Chemistry concept, the most benign ways to prevent of the pollution of the slurry is choosing appropriate oestrus-inducing veterinary pharmaceuticals (OIVPs) and the separation of the solid and liquid parts with adequate treatment methods. To our knowledge, this is the first paper on the adaptation of the YES test for medicine and slurry samples, extending its applicability. The adapted YES test turned out to be a sensitive, robust and reliable method for testing samples with potential estrogenic effect. Our dual approach was successful in evaluating the estrogenic effect of the slurry samples.

Variation of SMSI with the Au:Pd Ratio of Bimetallic Nanoparticles on TiO2(110).

Au/Pd nanoparticles are important in a number of catalytic processes. Here we investigate the formation of Au-Pd bimetallic nanoparticles on TiO2(110) and their susceptibility to encapsulation using scanning tunneling microscopy, as well as Auger spectroscopy and low energy electron diffraction. Sequentially depositing 5 MLE Pd and 1 MLE Au at 298 K followed by annealing to 573 K results in a bimetallic core and Pd shell, with TiOx encapsulation on annealing to ~ 800 K. Further deposition of Au on the pinwheel type TiOx layer results in a template-assisted nucleation of Au nanoclusters, while on the zigzag type TiOx layer no preferential adsorption site of Au was observed. Increasing the Au:Pd ratio to 3 MLE Pd and 2 MLE Au results in nanoparticles that are enriched in Au at their surface, which exhibit a strong resistance towards encapsulation. Hence the degree of encapsulation of the nanoparticles during sintering can be controlled by tuning the Au:Pd ratio.

The growth and thermal properties of Au deposited on Rh(111): formation of an ordered surface alloy.

Scanning tunnelling microscopy (STM), low energy ion scattering spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS) were applied for studying Au deposited on the Rh(111) surface. Both the deposition of Au at different substrate temperatures (400-800 K) and the effect of annealing Au deposited at 500 K were investigated. Gold deposition at 500 K, investigated by STM and LEIS methods, revealed that up to half monolayer Au the system exhibits clearly layer-by layer growth; however, above this coverage a slight deviation was identified, mainly due to kinetic and morphological effects. A continuous cover layer of Au was formed only above ∼2.5 monolayers (ML). Below this coverage, the pseudomorphic character of the Au overlayer was clearly proven by STM, but this feature disappears at 4 ML coverage. A moderate (5-10%) surface mixing of the two metals was observed only above 600 K, for both annealing the Au layer formed at lower temperatures and performing the deposition at elevated temperatures. Above 600 K a clear step-flow growth mechanism was verified. Depending on the Au coverage, a more extended mixing of the top layer and the sublayer was observed at even higher temperatures. In this case, nano-range ordering of the alloyed layer was detected by STM, where the lateral extension of the uniform commensurate (2 × 1) domains was around 4 × 4 nm2. In this case, the local intralayer mixing of Rh and Au can locally reach a value of 50%. The proposed structural model for the (2 × 1) alloy phase was also corroborated by HREELS investigations on CO adsorption.