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Opis: Strong electric fields exist between the electric double layer and charged surfaces. These fields impact molecular structures and chemistry at interfaces. We have developed a transparent electrode with infrared plasmonic enhancement sufficient to measure FTIR and two-dimensional infrared spectra at submonolayer coverages on the surface to which a voltage can be applied. Our device consists of an infrared transparent substrate, a 10–20 nm layer of conductive indium tin oxide (ITO), an electrically resistive layer of 3–5 nm Al2O3, and a 3 nm layer of nonconductive plasmonic gold. The materials and thicknesses are set to maximize the surface number density of the monolayer molecules, electrical conductivity, and plasmonic enhancement while minimizing background signals and avoiding Fano line shape distortions. The design was optimized by iteratively characterizing the material roughness and thickness with atomic force microscopy and electron microscopy and by monitoring the plasmon resonance enhancement with spectroscopy. The design is robust to repeated fabrication. This new electrode is tested on nitrile functional groups using a monolayer of 4-mercaptobenzonitrile as well as on CO and CC stretching modes using 4-mercaptobenzoic acid methyl ester. A voltage-dependent Stark shift is observed on both monolayers. We also observe that the transition dipole strength of the CN mode scales linearly with the applied voltage, providing a second way of measuring the surface electric field strength. We anticipate that this cell will enable many new voltage-dependent infrared experiments under applied voltages.
Ključne besede: two-dimensional infrared spectroscopy, infrared transparent substrate, voltage-dependent infrared experiments
Objavljeno: 24.02.2023; Ogledov: 118; Prenosov: 0
Polno besedilo (6,07 MB)

Ključne besede: super resolution microscopy, functionalized nanobodies
Objavljeno: 22.02.2023; Ogledov: 124; Prenosov: 0
Polno besedilo (4,07 MB)

Opis: The continuous use of Cu-based fungicides in viticulture has caused Cu accumulation in soils, which represents a major environmental and toxicological concern. The purpose of this study was to verify whether the organic management would be more resilient to temperature and moisture stresses in comparison to conventional practices. Two organic and two conventional vineyard soils, contrasting in pH, were exposed for six months to temperature stress (29 °C), moisture stress (10% water holding capacity—WHC), and combined stresses (29 °C—10% WHC). Main soil properties, Cu speciation, bioavailability, and leaching were monitored before and after 6 months’ incubation. Results confirm that the increase of temperature caused a decrease in both total organic carbon (TOC) and dissolved organic carbon (DOC) (up to 19% and 49%, respectively), a decrease in available ammonium, and an increase in nitrate. Moisture stress tends to mitigate some of these changes. Despite that, changes of Cu bioavailability and leaching were limited and rarely significant. Moreover, no regular trends between conventional and organic management could be observed. Changes in soil pH and total N (TN) appeared as the most influencing properties to regulate Cu behavior in vineyard soils. Calcareous soils were more resistant to environmental stresses compared to acid soils, regardless of the type of management (conventional or organic).
Ključne besede: soil copper, climate changes, soil organic matter, organic viticulture, BCR speciation
Objavljeno: 22.02.2023; Ogledov: 127; Prenosov: 6
Polno besedilo (2,57 MB)

Ključne besede: dušikov oksid, didušikov oksid, dušikov monoksid, smejalni plin, onesnaženje zraka
Objavljeno: 21.02.2023; Ogledov: 98; Prenosov: 0
Polno besedilo (4,46 MB)

Ključne besede: Cider, vino, jabolčni sok, HPLC-UV, Amino kisline, biogeni amini.
Objavljeno: 20.02.2023; Ogledov: 87; Prenosov: 0
Polno besedilo (27,64 MB)