152 research outputs found

    Співвідношення прямої мови та слів автора в художній німецькомовній прозі

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    Стилістична картина художнього твору, а також стилістичний потенціал прямої мови багато в чому залежать від того, у якому кількісному та структурному співвідношенні перебувають мова оповідача і мова персонажів. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/1773

    Revealing the main factors and two-way interactions contributing to food discolouration caused by iron-catechol complexation

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    Fortification of food with iron is considered to be an effective approach to counter the global health problem caused by iron deficiency. However, reactivity of iron with the catechol moiety of food phenolics leads to discolouration and impairs bioavailability. In this study, we investigated the interplay between intrinsic and extrinsic factors on food discolouration caused by iron-catechol complexation. To this end, a three-level fractional factorial design was implemented. Absorbance spectra were analysed using statistical methods, including PCA, HCA, and ANOVA. Furthermore, a direct link between absorbance spectra and stoichiometry of the iron-catechol complexes was confirmed by ESI-Q-TOF-MS. All statistical methods confirm that the main effects affecting discolouration were type of iron salt, pH, and temperature. Additionally, several two-way interactions, such as type of iron salt × pH, pH × temperature, and type of iron salt × concentration significantly affected iron-catechol complexation. Our findings provide insight into iron-phenolic complexation-mediated discolouration, and facilitate the design of iron-fortified foods.</p

    Unravelling discolouration caused by iron-flavonoid interactions: Complexation, oxidation, and formation of networks

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    Iron-flavonoid interactions in iron-fortified foods lead to undesirable discolouration. This study aimed to investigate iron-mediated complexation, oxidation, and resulting discolouration of flavonoids by spectrophotometric and mass spectrometric techniques. At pH 6.5, iron complexation to the 3–4 or 4–5 site instantly resulted in bathochromic shifting of the π → π* transition bands, and complexation to the 3ʹ-4ʹ site (i.e. catechol moiety) induced a π → dπ transition band. Over time, iron-mediated oxidative degradation and coupling reactions led to the formation of hydroxybenzoic acid derivatives and dehydrodimers, respectively resulting in a decrease or increase in discolouration. Additionally, we employed XRD, SEM, and TEM to reveal the formation of insoluble black metal-phenolic networks (MPNs). This integrated study on iron-mediated complexation and oxidation of flavonoids showed that the presence of the C2–C3 double bond in combination with the catechol moiety and either the 4-carbonyl or 3-hydroxyl increased the intensity of discolouration, extent of oxidation, and formation of MPNs

    Treatment failure and hospital readmissions in severe COPD exacerbations treated with azithromycin versus placebo - A post-hoc analysis of the BACE randomized controlled trial

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    Background: In the BACE trial, a 3-month (3 m) intervention with azithromycin, initiated at the onset of an infectious COPD exacerbation requiring hospitalization, decreased the rate of a first treatment failure (TF); the composite of treatment intensification (TI), step-up in hospital care (SH) and mortality. Objectives: (1) To investigate the intervention's effect on recurrent events, and (2) to identify clinical subgroups most likely to benefit, determined from the incidence rate of TF and hospital readmissions. Methods: Enrolment criteria included the diagnosis of COPD, a smoking history of ≥10 pack-years and ≥ 1 exacerbation in the previous year. Rate ratio (RR) calculations, subgroup analyses and modelling of continuous variables using splines were based on a Poisson regression model, adjusted for exposure time. Results: Azithromycin significantly reduced TF by 24% within 3 m (RR = 0.76, 95%CI:0.59;0.97, p = 0.031) through a 50% reduction in SH (RR = 0.50, 95%CI:0.30;0.81, p = 0.006), which comprised of a 53% reduction in hospital readmissions (RR = 0.47, 95%CI:0.27;0.80; p = 0.007). A significant interaction between the intervention, CRP and blood eosinophil count at hospital admission was found, with azithromycin significantly reducing hospital readmissions in patients with high CRP (> 50 mg/L, RR = 0.18, 95%CI:0.05;0.60, p = 0.005), or low blood eosinophil count (<300cells/μL, RR = 0.33, 95%CI:0.17;0.64, p = 0.001). No differences were observed in treatment response by age, FEV1, CRP or blood eosinophil count in continuous analyses. Conclusions: This post-hoc analysis of the BACE trial shows that azithromycin initiated at the onset of an infectious COPD exacerbation requiring hospitalization reduces the incidence rate of TF within 3 m by preventing hospital readmissions. In patients with high CRP or low blood eosinophil count at admission this treatment effect was more pronounced, suggesting a potential role for these biomarkers in guiding azithromycin therapy. Trial registration: ClinicalTrials.gov number. NCT02135354. © 2019 The Author(s)

    Peroxidase Can Perform the Hydroxylation Step in the "oxidative Cascade" during Oxidation of Tea Catechins

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    The formation of black tea thearubigins involves at least two of the following oxidation steps: (i) oligomerization, (ii) rearrangement, and (iii) hydroxylation. The first two are mainly catalyzed by polyphenol oxidase (PPO), whereas the enzyme responsible for hydroxylation has not yet been identified. Two main oxidative activities, peroxidase (POD) and PPO, occur in tea leaves. POD was hypothesized to be responsible for hydroxylation. Model systems with horseradish POD and mushroom tyrosinase were used investigating hydroxylation of theaflavins (TFs). POD was found capable of hydroxylation. TFs with up to five extra hydroxyl groups were annotated by their MS2 data. Hydroxylation by POD was also shown for theanaphtoquinones, theatridimensins, and dehydrodicatechins. The H2O2 concentration influenced the extent of hydroxylation, decreasing it at concentrations above 0.01 mM. TFs with up to five extra hydroxyl groups and traces of other hydroxylated oligomeric catechins could be annotated in black tea without any sample pretreatment, using a selective screening method with reversed-phase ultrahigh-performance liquid chromatography mass spectrometry.</p
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