Determination of catechin and epicatechin in the peel of apple varieties resistant and non-resistant to apple scab

Catechin and epicatechin were analysed in the peel of six apple cultivars (three resistant and three non-resistant to apple scab). Two methods of analytical sample preparation following extraction were tested: solid phase extraction and column separation with Sephadex LH-20 coupled to a differential refractometric detector. Prior to GC and GC-MS analyses, these compounds were silylized. This permitted co-injection with standards and the comparison of retention values and mass spectra with those recorded for standards. The content of catechin and epicatechin in apple peel is discussed in relation to the resistance of apple trees to scab.     

Chromatographic and capillary electrophoretic determination of microcystins

Microcystins are cyclic peptide hepatotoxins that are produced during blooming of cyanobacteria. In recent two decades they gained a great interest because of the related ecological and public health risks. Over 70 different analogs of microcystins have been isolated from natural blooms and laboratory cultures of cyanobacteria. Because they are inhibitors of protein phosphatases they act as tumor promoters, but on the other hand, inhibitive enzymatic and ELISA methods may be employed for their screening or quantitative determination. Much larger analytical potential for this purpose have, however high‐performance separation chromatographic and electromigration techniques. Based on about 70 references from original journal papers these methods are reviewed together with presentation of their preconcentration methods and clean‐up procedures for analyzing environmental samples. Some attention is also focused on increasing application of LC/MS methods, and comparison of separation techniques with immunochemical or enzymatic methods.     

The impact of insecticides containing deltamethrin and cyfluthrin on the composition of surface compounds in the larvae,females and males of Tenebrio molitor

This paper presents the effect of insecticides on the composition of the surface compounds of one of the most harmful insects, Tenebrio molitor, by analysis using GC–MS. As a result of the use of insecticides, the composition of the chemical compounds on the surface of insects changes, depending on the insecticides used. The most numerous groups of the marked compounds were fatty acids, alkanes, esters and sterols. The content of the identified compounds in the larvae increased at both 24 and 48 h after the application of insecticides, in comparison with the control samples. The content of identified compounds in the samples taken from the females increased 24, 48 and 72 h after the application of insecticides in comparison with the control samples. By contrast, in samples prepared from males, the content of identified compounds decreased 24 h after the application of insecticides, compared with the control samples. The highest content of chemical compounds was for fatty acids and alkanes after the use of insecticides. The content of fatty acids after the application of the insecticide with deltamethrin was 62.1 ± 3.3–466.9 ± 5.9 μg/g, and after the application of the insecticide with cyfluthrin was 49.9 ± 1.9–458.3 ± 4.2 μg/g. However, the content of alkanes after the use of deltamethrin was 115.6 ± 4.2–4672.0 ± 32.1 μg/g, and after the use of cyfluthrin was 189.4 ± 3.8–3975.0 ± 10.2 μg/g.     

Indirectly Detected DNP-Enhanced 17O NMR Spectroscopy: Observation of Non-Protonated Near-Surface Oxygen at Naturally Abundant Silica and Silica-Alumina

Recent studies have shown that dynamic nuclear polarization (DNP) can be used to detect ¹⁷O solid-state NMR spectra of naturally abundant samples within a reasonable experimental time. Observations using indirect DNP, which relies on ¹H mediation in transferring electron hyperpolarization to ¹⁷O, are currently limited mostly to hydroxyls. Direct DNP schemes can hyperpolarize non-protonated oxygen near the radicals; however, they generally offer much lower signal enhancements. In this study, we demonstrate the detection of signals from non-protonated ¹⁷O in materials containing silicon. The sensitivity boost that made the experiment possible originates from three sources: indirect DNP excitation of ²⁹Si via protons, indirect detection of ¹⁷O through ²⁹Si nuclei using two-dimensional ²⁹Si{¹⁷O} D-HMQC, and Carr-Purcell-Meiboom-Gill refocusing of ²⁹Si magnetization during acquisition. This ²⁹Si-detected scheme enabled, for the first time, 2D ¹⁷O−²⁹Si heteronuclear correlation spectroscopy in mesoporous silica and silica-alumina surfaces at natural abundance. In contrast to the silanols showing motion-averaged ¹⁷O signals, the framework oxygens exhibit unperturbed powder patterns as unambiguous fingerprints of surface sites. Along with hydroxyl oxygens, detection of these moieties will help in gaining more atomistic-scale insights into surface chemistry.     

Sustainable Drying and Torrefaction Processes of Miscanthus for Use as a Pelletized Solid Biofuel and Biocarbon-Carrier for Fertilizers

Miscanthus is resistant to dry, frosty winters in Poland and most European Union countries. Miscanthus gives higher yields compared to native species. Farmers can produce Miscanthus pellets after drying it for their own heating purposes. From the third year, the most efficient plant development begins, resulting in a yield of 25–30 tons of dry matter from an area of 1 hectare. Laboratory scale tests were carried out on the processes of drying, compacting, and torrefaction of this biomass type. The analysis of the drying process was conducted at three temperature levels of the drying agent (60, 100, and 140 °C). Compaction on a hydraulic press was carried out in the pressure range characteristic of a pressure agglomeration (130.8–457.8 MPa) at different moisture contents of the raw material (0.5% and 10%). The main interest in this part was to assess the influence of drying temperature, moisture content, and compaction pressure on the specific densities (DE) and the mechanical durability of the pellets (DU). In the next step, laboratory analyses of the torrefaction process were carried out, initially using the Thermogravimetric Analysis TGA and Differential Scaning Calorimeter DSC techniques (to assess activation energy (EA)), followed by a flow reactor operating at five temperature levels (225, 250, 275, 300, and 525 °C). A SEM analysis of Miscanthus after torrefaction processes at three different temperatures was performed. Both the parameters of biochar (proximate and ultimate analysis) and the quality of the torgas (volatile organic content (VOC)) were analyzed. The results show that both drying temperature and moisture level will affect the quality of the pellets. Analysis of the torrefaction process shows clearly that the optimum process temperature would be around 300–340 °C from a mass loss ratio and economical perspective.     

Role of Gut Microbiota,Probiotics and Prebiotics in the Cardiovascular Diseases

In recent years, there has been a growing interest in identifying and applying new, naturally occurring molecules that promote health. Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer health benefits on the host”. Quite a few fermented products serve as the source of probiotic strains, with many factors influencing the effectiveness of probiotics, including interactions of probiotic bacteria with the host’s microbiome. Prebiotics contain no microorganisms, only substances which stimulate their growth. Prebiotics can be obtained from various sources, including breast milk, soybeans, and raw oats, however, the most popular prebiotics are the oligosaccharides contained in plants. Recent research increasingly claims that probiotics and prebiotics alleviate many disorders related to the immune system, cancer metastasis, type 2 diabetes, and obesity. However, little is known about the role of these supplements as important dietary components in preventing or treating cardiovascular disease. Still, some reports and clinical studies were conducted, offering new ways of treatment. Therefore, the aim of this review is to discuss the roles of gut microbiota, probiotics, and prebiotics interventions in the prevention and treatment of cardiovascular disease.     

Modification of Polylactide Nonwovens with Carbon Nanotubes and Ladder Poly(silsesquioxane)

Electrospun nonwovens of poly(L-lactide) (PLLA) modified with multiwall carbon nanotubes (MWCNT) and linear ladder-like poly(silsesquioxane) with methoxycarbonyl side groups (LPSQ-COOMe) were obtained. MWCNT and LPSQ-COOMe were added to the polymer solution before the electrospinning. In addition, nonwovens of PLLA grafted to modified MWCNT were electrospun. All modified nonwovens exhibited higher tensile strength than the neat PLA nonwoven. The addition of 10 wt.% of LPSQ-COOMe and 0.1 wt.% of MWCNT to PLLA increased the tensile strength of the nonwovens 2.4 times, improving also the elongation at the maximum stress.     

Searching for Potential Markers of Glomerulopathy in Urine by HS-SPME-GC×GC TOFMS

Volatile organic compounds (VOCs) exiting in urine are potential biomarkers of chronic kidney diseases. Headspace solid phase microextraction (HS-SPME) was applied for extraction VOCs over the urine samples. Volatile metabolites were separated and identified by means of two-dimensional gas chromatography and time of flight mass spectrometry (GC × GC TOF MS). Patients with glomerular diseases (n = 27) and healthy controls (n = 20) were recruited in the study. Different VOCs profiles were obtained from patients and control. Developed methodology offers the opportunity to examine the metabolic profile associated with glomerulopathy. Four compounds found in elevated amounts in the patients group, i.e., methyl hexadecanoate; 9-hexadecen-1-ol; 6,10-dimethyl-5,9-undecadien-2-one and 2-pentanone were proposed as markers of glomerular diseases.     

Boron- versus Nitrogen-Centered Nucleophilic Reactivity of (Cyano)hydroboryl Anions: Synthesis of Cyano(hydro)organoboranes and 2-Aza-1,4-diborabutatrienes

Cyclic alkyl(amino)carbene-stabilized (cyano)hydroboryl anions were synthesized by deprotonation of (cyano)dihydroborane precursors. While they display boron-centered nucleophilic reactivity towards organohalides, generating fully unsymmetrically substituted cyano(hydro)organoboranes, they show cyano-nitrogen-centered nucleophilic reactivity towards haloboranes, resulting in the formation of hitherto unknown linear 2-aza-1,4-diborabutatrienes.     

The Role of Alkali Cation Intercalates on the Electrochemical Characteristics of Nb2CTX MXene for Energy Storage

The intercalation of cations into layered-structure electrode materials has long been studied in depth for energy storage applications. In particular, Li⁺-, Na⁺-, and K⁺-based cation transport in energy storage devices such as batteries and electrochemical capacitors is closely related to the capacitance behavior. We have exploited different sizes of cations from aqueous salt electrolytes intercalating into a layered Nb₂CT_x electrode in a supercapacitor for the first time. As a result, we have demonstrated that capacitive performance was dependent on cation intercalation behavior. The interlayer spacing expansion of the electrode material can be observed in Li₂SO₄, Na₂SO₄, and K₂SO₄ electrolytes with d-spacing. Additionally, our results showed that the Nb₂CT_x electrode exhibited higher electrochemical performance in the presence of Li₂SO₄ than in that of Na₂SO₄ and K₂SO₄. This is partly because the smaller-sized Li⁺ transports quickly and intercalates between the layers of Nb₂CT_x easily. Poor ion transport in the Na₂SO₄ electrolyte limited the electrode capacitance and presented the lowest electrochemical performance, although the cation radius follows Li⁺>Na⁺>K⁺. Our experimental studies provide direct evidence for the intercalation mechanism of Li⁺, Na⁺, and K⁺ on the 2D layered Nb₂CT_x electrode, which provides a new path for exploring the relationship between intercalated cations and other MXene electrodes.