Physicochemical,Antioxidant, Microstructural Properties and Bioaccessibility of Dark Chocolate with Plant Extracts

In this study, dark chocolates (DCh) containing zinc lactate (ZnL) were enriched with extracts from elderberries (EFrE), elderflowers (EFlE), and chokeberries (ChFrE) to improve their functional properties. Both dried plant extracts and chocolates were analyzed for antioxidant capacity (AC) using four different analytical methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric ion-reducing antioxidant capacity (CUPRAC), and ferric-reducing antioxidant power (FRAP), while total phenolic content (TPC) was determined by Folin–Ciocalteu (F–C) assay. An increase in antioxidant properties of fortified chocolates was found, and the bioaccessibility of their antioxidants was evaluated. The highest AC and TPC were found in ChFrE and chocolate with chokeberries (DCh + ChFrE) before and after simulated in vitro digestion. Bioaccessibility studies indicated that during the simulated digestion the AC of all chocolates reduced significantly, whereas insignificant differences in TPC results were observed between chemical and physiological extracts. Moreover, the influence of plant extracts on physicochemical parameters such as moisture content (MC), fat content (FC), and viscosity of chocolates was estimated. Furthermore, scanning electron microscopy with dispersive energy spectroscopy (SEM-EDS) was used to analyze surface properties and differences in the chemical composition of chocolates without and with additives.     

Fe-N-C catalysts for oxygen electroreduction under external magnetic fields:Reduction of magnetic O2 to nonmagnetic H2O

An extensive analysis of iron-nitrogen-carbon(Fe-N-C)electrocatalysts synthesis and activity is presented concerning synthesis conditions such as initial Fe content,pyrolysis temperature and atmosphere(inert N₂,reducing NH₃,oxidizing Cl₂ and their sequential combinations)and the influence of an external magnetic field on their performance in oxygen reduction reaction(ORR).Thermosetting porous polymers doped with FeCl₃ were utilized as the Fe-N-C catalysts precursors.The pyrolysis temperature was varied within a 700-900℃range.The temperature and atmosphere of pyrolysis strongly affect the porosity and compositi on of the resultant Fe-N-C catalysts,while the in itial amount of Fe precursor shows much weaker impact.Pyrolysis under NH₃ yields materials similar to those pyrolyzed under an inert atmosphere(N₂).In contrast,pyrolysis under Cl₂ yields carbon of peculiar character with highly disordered structure and extensive microporosity.The application of a static external magnetic field strongly enhances the ORR process(herein studied in an alkaline environment)and the enhancement correlates with the Fe content in the Fe-N-C catalysts.The Fe-N-C materials containing ferromagnetic iron phase embedded in N-doped microporous carbon constitute attractive catalysts for magnetic field-aided anion exchange membrane fuel cell technology.     

Uptake of Pharmaceutical Pollutants and Their Metabolites from Soil Fertilized with Manure to Parsley Tissues

Manure is a major source of soil and plant contamination with veterinary drugs residues. The aim of this study was to evaluate the uptake of 14 veterinary pharmaceuticals by parsley from soil fertilized with manure. Pharmaceutical content was determined in roots and leaves. Liquid chromatography coupled with tandem mass spectrometry was used for targeted analysis. Screening analysis was performed to identify transformation products in the parsley tissues. A solid-liquid extraction procedure was developed combined with solid-phase extraction, providing recoveries of 61.9–97.1% for leaves and 51.7–95.6% for roots. Four analytes were detected in parsley: enrofloxacin, tylosin, sulfamethoxazole, and doxycycline. Enrofloxacin was detected at the highest concentrations (13.4–26.3 ng g⁻¹). Doxycycline accumulated mainly in the roots, tylosin in the leaves, and sulfamethoxazole was found in both tissues. 14 transformation products were identified and their distribution were determined. This study provides important data on the uptake and transformation of pharmaceuticals in plant tissues.     

Porous Molecular Capsules as Non-Polymeric Transducers of Mechanical Forces to Mechanophores

Mechanical grinding/milling can be regarded as historically the first technology for changing the properties of matter. Mechanically activated molecular units (mechanophores) can be present in various structures: polymers, macromolecules, or small molecules. However, only polymers have been reported to effectively transduce energy to mechanophores, which induces breakage of covalent bonds. In this paper, a second possibility is presented—molecular capsules as stress-sensitive units. Mechanochemical encapsulation of fullerenes in cystine-based covalent capsules indicates that complexation takes place in the solid state, despite the fact that the capsules do not possess large enough entrance portals. By using a set of solvent-free MALDI (sf-MALDI) and solid-state NMR (ss-NMR) experiments, it has been proven that encapsulation proceeds during milling and in this process hydrazones and disulfides get activated for breakage, exchange, and re-forming. The capsules are porous and therefore prone to collapse under solvent-free conditions and their conformational rigidity promotes the collapse by the breaking of covalent bonds.     

The influence of cation arrangement on the EPR spectrum of Mn2+ in the spinel compounds CdB2X4

CdB₂X₄ spinels—B = Sc, Y, Lu; X = S, Se—were synthesized and their lattice constants were determined. After Mn²⁺ doping they were investigated by the EPR method over the temperature range 4.2–330 K. The temperature dependence of the hyperfine structure constant, A, was described by the ?imanek-Orbach equation and its parameters were determined. Chemical bonds in the studied spinels were characterized in more detail to obtain a linear dependence of the A constants on the modified covalency parameter.     

The microenvironment effect on the generation of reactive oxygen species by Pd-bacteriopheophorbide

Generation of reactive oxygen species (ROS) is the hallmark of important biological processes and photodynamic therapy (PDT), where ROS production results from in situ illumination of certain dyes. Here we test the hypothesis that the yield, fate, and efficacy of the species evolved highly depend on the dye's environment. We show that Pd-bacteriopheophorbide (Pd-Bpheid), a useful reagent for vascular targeted PDT (VTP) of solid tumors, which has recently entered into phase II clinical trials under the code name WST09 (trade name TOOKAD), forms appreciable amounts of hydroxyl radicals, superoxide radicals, and probably hydrogen peroxide in aqueous medium but not in organic solvents where singlet oxygen almost exclusively forms. Evidence is provided by pico- and nanosecond time-resolved spectroscopies, ESR spectroscopy with spin-traps, time-resolved singlet oxygen phosphorescence, and chemical product analysis. The quantum yield for singlet oxygen formation falls from approximately 1 in organic solvents to approximately 0.5 in membrane-like systems (micelles or liposomes), where superoxide and hydroxyl radicals form at a minimal quantum yield of 0.1%. Analysis of photochemical products suggests that the formation of oxygen radicals involves both electron and proton transfer from (3)Pd-Bpheid at the membrane/water interface to a colliding oxygen molecule, consequently forming superoxide, then hydrogen peroxide, and finally hydroxyl radicals, with no need for metal catalysis. The ability of bacteriochlorophyll (Bchl) derivatives to form such radicals upon excitation at the near infrared (NIR) domain opens new avenues in PDT and research of redox regulation in animals and plants.     

Modification of iodometric determination of total and reactive sulfide in environmental samples

In iodometric determination of sulfide two reactions are taking place when alkaline solution is added to HCl acid-iodine. The main oxidation reaction (1), H(2)S+I(2)=2HI+S; and side reaction of sulfide (2), S(-2)+4I(2)+8OH(-)=SO(4)(2-)+8I(-)+4H(2)O. Preference of reaction (2) over (1) is dependent on pH increasing to >7. When sulfide solution of pH 9 was mixed with HCl acid-iodine, the recovery exceeded 120%, but the recovery of a solution with a pH of 13 exceeded 200%. To eliminate the side reaction in iodometric titration, the sulfide solution must be acidic when it is mixed with HCl-iodine. To avoid the side reaction (2), the pH of sulfide solutions were adjusted with acetic acid to pH 5.5, mixed with HCl-iodine solution and then titrated with standard thiosulfate with precision and accuracy <+/-3%.     

Probing the spatial dependence of the emission spectrum of single human retinal lipofuscin granules using near-field scanning optical microscopy

The emission spectra of single lipofuscin granules are examined using spectrally resolved confocal microscopy and near-field scanning optical microscopy (NSOM). The emission spectrum varies among the granules examined revealing that individual granules are characterized by different distributions of fluorophores. The range of spectra observed is consistent with in vivo spectra of human retinal pigment epithelium cells. NSOM measurements reveal that the shape of the spectrum does not vary with position within the emissive regions of single lipofuscin granules. These results suggest that the relative distribution of fluorophores within the emissive regions of an individual granule is homogeneous on the spatial scale approximately 150 nm.