Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

A recent development for selective ammonia oxidation into nitrogen and water vapor (NH₃-SCO) over noble metal-based catalysts is covered in the mini-review. As ammonia (NH₃) can harm human health and the environment, it led to stringent regulations by environmental agencies around the world. With the enforcement of the Euro VI emission standards, in which a limitation for NH₃ emissions is proposed, NH₃ emissions are becoming more and more of a concern. Noble metal-based catalysts (i.e., in the metallic form, noble metals supported on metal oxides or ion-exchanged zeolites, etc.) were rapidly found to possess high catalytic activity for NH₃ oxidation at low temperatures. Thus, a comprehensive discussion of property-activity correlations of the noble-based catalysts, including Pt-, Pd-, Ag- and Au-, Ru-based catalysts is given. Furthermore, due to the relatively narrow operating temperature window of full NH₃ conversion, high selectivity to N₂O and NO_x as well as high costs of noble metal-based catalysts, recent developments are aimed at combining the advantages of noble metals and transition metals. Thus, also a brief overview is provided about the design of the bifunctional catalysts (i.e., as dual-layer catalysts, mixed form (mechanical mixture), hybrid catalysts having dual-layer and mixed catalysts, core-shell structure, etc.). Finally, the general conclusions together with a discussion of promising research directions are provided.     

Determination of Metallic Impurities by ICP-MS Technique in Eyeshadows Purchased in Poland. Part I

Eye shadows, which are products willingly and frequently used by women and even children, have been reported in literature to contain toxic metals. In this work, a total of 94 eye shadows samples available on the Polish market were collected. Eye shadow products have been selected in order to include several parameters important from the point of view of the typical consumer such as: product type (mat/pearl), consumer group (for adults and children), price range (very cheap, medium price, expensive and very expensive), color (twelve different colors were tested), manufacturer (eight brands were investigated) or country of production (four countries were included). The concentration of selected metals (Ag, Ba, Bi, Cd, Pb, Sr, Tl) was determined by ICP-MS technique after the sample extraction with a mixture of nitric acid and hydrogen peroxide in a microwave closed system. For Ag, Cd and Tl, some results were below the established limit of quantification for the employed technique. The presence of strontium, barium, lead and bismuth was confirmed in all studied samples. The obtained results for analyzed elements were, in general, quite comparable with the data reported by other authors. A small number of samples exceeding the permissible values (two samples were beyond the limit value for Cd of 0.5 mg/kg and one exceed the acceptable concentration for Pb of 10 mg/kg) also proves a relatively good condition of the Polish cosmetics market and suggests insubstantial risk for the potential consumers. The results gathered for some of the eye shadows intended for children turned out to be alarmingly high, in particular for elements such as Cd. The highest concentration of Cd reached almost 4 mg/kg, while of Pb amounted to 16 mg/kg. The presence of the statistically significant differences was confirmed for all included parameters with an exception of the color of the eye shadow. Considering the results acquired only for Cd and Pb with respect to the country of origin, the least contaminated cosmetics by metallic impurities seem to be the one produced in Canada, while the ones presenting the highest health risk among all studied eye shadows are make-up cosmetics originating from Poland and Italy. Multivariate analysis of a large data set using CA methods and PCA provided valuable information on dependencies between variables and objects.     

Arene-Ruthenium(II) Complexes with Carbothiamidopyrazoles as a Potential Alternative for Antibiotic Resistance in Human

To meet the demand for alternatives to commonly used antibiotics, this paper evaluates the antimicrobial potential of arene-ruthenium(II) complexes and their salts, which may be of value in antibacterial treatment. Their antimicrobial activity (MIC, MBC/MFC) was examined in vitro against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Candida albicans and compared with classic antibiotics used as therapeutics. Selected arene-ruthenium(II) complexes were found to have synergistic effects with oxacillin and vancomycin against staphylococci. Their bactericidal effect was found to be associated with cell lysis and the ability to cut microbial DNA. To confirm the safety of the tested arene-ruthenium(II) complexes in vivo, their cytotoxicity was also investigated against normal human foreskin fibroblasts (HFF-1). In addition, the antioxidant and thus pro-health potential of the compounds, i.e., their nonenzymatic antioxidant capacity (NEAC), was determined by two different methods: ferric-TPTZ complex and DPPH assay.     

Bioaccessibility of Antioxidants in Blackcurrant Juice after Treatment Using Supercritical Carbon Dioxide

Blackcurrant juice (Ribes nigrum L.) was subjected to supercritical carbon dioxide (SCCD) at 10, 30, and 60 MPa for 10 min at 45 °C, as well as thermally treated at 45 and 85 °C for 10 min to determine the stability, antioxidant capacity (AC), and bioaccessibility (BAc) of vitamin C, total anthocyanins, and their individual monomers. An in vitro gastrointestinal digestion model completed with dialysis was used to assess BAc. The use of SCCD at each of the pressures applied improved the stability of vitamin C, total anthocyanins, and AC before in vitro digestion. As a result of digestion, the total content of vitamin C, anthocyanins, and AC decreased. The highest BAc of vitamin C was noted in fresh juice (FJ) (40%) and after mild heat treatment at 45 °C (T45) (46%). The highest BAc of total anthocyanins was also noted in the FJ (4.4%). The positive effect of the application of SCCD on the BAc of the delphinidin-3-O-glycosides was observed compared to T45 and thermal pasteurization at 85 °C (T85). Although SCCD did not significantly improve the BAc of vitamin C and total anthocyanins, the higher AC of SCCD samples after intestinal digestion (ABTS+• and DPPH•) and in dialysate (ABTS+•) compared to thermally treated was observed. The protocatechuic acid was detected by UPLC-PDA-MS/MS as the major metabolite formed during the digestion of delphinidin-3-O-rutinoside. This may indicate the influence of SCCD on improvement of the accessibility of antioxidants for digestion, thanks to which more metabolites with high antioxidant activity were released.     

A Uniform Benchmark for Testing SsrA-Derived Degrons in the Escherichia coli ClpXP Degradation Pathway

The ssrA degron is commonly used in fusion proteins to control protein stability in bacteria or as an interaction module. These applications often rely on the modular activities of the ssrA tag in binding to the SspB adaptor and in engaging the ClpXP protease. However, a comparison of these activities for a substantial standard set of degron variants has not been conducted previously, which may hinder the development of new variants optimized exclusively for one application. Here, we strive to establish a benchmark that will facilitate the comparison of ssrA variants under uniform conditions. In our workflow, we included methods for expression and purification of ClpX, ClpP, SspB and eGFP-degrons, assays of ClpX ATPase activity, of eGFP-degron binding to SspB and for measuring eGFP-degron degradation in vitro and in vivo. Using uniform, precise and sensitive methods under the same conditions on a range of eGFP-degrons allowed us to determine subtle differences in their properties that can affect their potential applications. Our findings can serve as a reference and a resource for developing targeted protein degradation approaches.     

β-Cyclodextrin Derivative Grafted on Silica Gel Represents a New Polymeric Sorbent for Extracting Nitisinone from Model Physiological Fluids

Nitisinone (NTBC) is used in the treatment of disorders affecting the tyrosine pathway, including hereditary tyrosinemia type I, alkaptonuria, and neuroblastoma. An inappropriate dosage of this therapeutic drug causes side effects; therefore, it is necessary to develop a rapid and sensitive method to monitor the content of NTBC in patients’ blood. This study aimed to develop anew polymeric sorbent containing β-cyclodextrin (β-CD) derivatives grafted on silica gel to effectively extract NTBC from model physiological fluids. The inclusion complex formed between β-CD and NTBC was examined by proton nuclear magnetic resonance spectroscopy. The novel sorbents with derivatives of β-CD were prepared on modified silica gel using styrene as a comonomer, ethylene glycol dimethacrylate as a crosslinking agent, and 2,2′-azo-bis-isobutyronitrile as a polymerization initiator. The obtained products were characterized via Fourier transform infrared spectroscopy and then used as sorbents as part of a solid phase extraction technique. High NTBC recovery (70%indicated that the developed polymeric sorbent may be suitable for extracting this compound from patients’ blood samples.     

Solubility of Solid 1-Hexene and 2-Methylpentane in Liquid Argon and Nitrogen at the Standard Boiling Points of the Solvents

The solubilities of solid 1-hexene and 2-methylpentane in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. The experimental value of the mole fraction solubility of solid 1-hexene in liquid argon at 87.3 K is (3.87 ± 0.74) × 10^-7 and (7.94 ± 2.47) × 10^-9 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid 2-methylpentane in liquid argon at 87.3 K is (1.45 ± 0.36) × 10^-5 and (6.80 ± 2.16) × 10^-8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters 1₁₂ were also calculated. At 90.0 K, liquid argon is a better solvent for solid 1-hexene and 2-methylpentane than is liquid nitrogen.     

Experimental and predicted viscosities of the binary system (n-hexane + 1,3-dioxolane) and for the ternary system (n-hexane + 1,3-dioxolane + 1-butanol) at 298.15 and 313.15 K

Viscosities of the ternary system n-hexane+1,3-dioxolane+1-butanol and the binary system n-hexane+1,3-dioxolane have been measured at atmospheric pressure at 298.15 and 313.15 K. Viscosity deviations for the binary and ternary systems were calculated from experimental data and fitted to Redlich–Kister and Cibulka equations, respectively. The group contribution method proposed by Wu has been used to predict the viscosity of all mixtures.     

Distigmasterol-Modified Acylglycerols as New Structured Lipids—Synthesis,Identification and Cytotoxicity

Plant sterols, also referred as phytosterols, have been known as bioactive compounds which have cholesterol-lowering properties in human blood. It has been established that a diet rich in plant sterols or their esters alleviates cardiovascular diseases (CVD), and also may inhibit breast, colon and lung carcinogenesis. Phytosterols, in their free and esterified forms, are prone to thermo-oxidative degradation, where time and temperature affect the level of degradation. Looking for new derivatives of phytosterols with high thermo-oxidative stability for application in foods, our idea was to obtain novel structured acylglycerols in which two fatty acid parts are replaced by stigmasterol residues. In this work, asymmetric (1,2- and 2,3-) distigmasterol-modified acylglycerols (dStigMAs) were synthesized by the covalent attachment of stigmasterol residues to sn-1 and sn-2 or sn-2 and sn-3 positions of 3-palmitoyl-sn-glycerol or 1-oleoyl-sn-glycerol, respectively, using a succinate or carbonate linker. The chemical structures of the synthesized compounds were identified by NMR, HR-MS, and IR data. Moreover, the cytotoxicity of the obtained compounds was determined. The dStigMAs possessing a carbonate linker showed potent cytotoxicity to cells isolated from the small intestine and colon epithelium and liver, whereas the opposite results were obtained for compounds containing a succinate linker.     

The Solvability of the Discrete Boundary Value Problem on the Half-Line

This paper provides conditions for the existence of a solution to the second-order nonlinear boundary value problem on the half-line of the form with αx(0)+βa(0)Δx(0)=0,x(∞)=d, where d,α,β∈R, α2+β2>0. To achieve our goal, we use Schauder’s fixed-point theorem and the perturbation technique for a Fredholm operator of index 0. Moreover, we construct the necessary condition for the existence of a solution to the considered problem.