Effect of the Iron Reduction Index on the Mechanical and Chemical Properties of Continuous Basalt Fiber

Basalt glass belongs to the iron-rich aluminosilicate glass system; thus, the iron content and the iron redox index (IRI=Fe2+/Fetotal) influence the viscosity, density, mechanical and chemical properties of basalt fiber (BF). In this work, continuous BFs with IRIs ranging from 0.21–0.87 were prepared by adding a different amount of redox agents. An economical and easily accessible testing method—the spectral photometric method with 1,10-phenanthroline—is applied to measure the IRI with convinced accuracy, which has been approved by Mössbauer spectra and X-ray fluorescence analysis. The tensile strength of the BF samples increases approximately linearly with increasing IRI as a function of σ = 227.9 IRI + 780.0 . The FT-IR results indicate that, with increasing IRI, the ferric ions are replaced by the much stronger network formers (Al3+ and Si4+), hence the increased the tensile strength. The X-ray diffraction results show an amorphous nature of BF samples. Moreover, the tensile strength is significantly decreased after the alkali corrosion, which is partly attributed to the severe surface damaging according to the SEM results. This work proved the feasibility of mechanical property improvement in BF production by controlling the iron redox index.

Клінічна ефективність лікувально-профілактичних заходів при хронічному катаральному гінгівіті

Treatment of inflammatory periodontal diseases remains an urgent problem of dentistry as a result of frequent recurrence, inflammation in alveolar bone tissue with periodontal tissue destruction, so developing pathogenetic effects in treating the chronic catarrhal gingivitis is timely.The aim of the study – to conduct the pathogenetic treatment of gingivitis and the assessment of its effectiveness.Materials and Methods. 67 children aged 16–18 years, suffering from chronic catarrhal gingivitis, were taken under clinical supervision and divided into groups: the main (35 children) and the comparative (32 children). All children underwent conventional therapy in accordance with the protocols for the provision of medical care – basic therapy. In the main group, for a month, pathogenetic agents were used: an anti-inflammatory gel with neovitin, hygiene products were recommended. In the comparative group, 3 % hydrogen peroxide solution was used for local therapy, for rinsing of the mouth (during the first week of treatment) – Rotokan, a therapeutic and prophylactic toothpaste.Examination and control examinations were carried out with the hygienic state of the mouth determined by the hygienic index of Green-Vermillion (ОНІ-S), prevalence and intensity of the inflammatory process in the gums with the help of the Schiller-Pisarev test and the PMA index, oral fluid index (content of total glutathione, oxidized and reduced glutathione, glutathione redox index).Results and Discussion. Immediately after the treatment in the main group, the decrease in the PMA index was 2.6 times; GI – in 1.4 times, ONI-S – in 1.7 times. A reduction in the treatment period of adolescents in the application of the proposed therapeutic scheme is established. The content of total glutathione in the main group was significantly higher (p <0.05) than that of the comparator group before treatment (by 12.2 %) and comparing the indicator in 0.5 years (by 8.8 %). In this observation period, the difference between the content of oxidized and reduced glutathione in persons of the main and comparative groups was also significant – 1.8 times and 1.2 times, respectively. In addition, the redox index of glutathione in the main group increased and even exceeded the control group, although there was no significant difference.Conclusion. The use of the proposed therapy with gel with neovitin contributed to the best results of treatment: reducing the degree of inflammation of the gums, the number of visits to the doctor, improving the indices of nonspecific protection in the oral fluid and, to a greater extent, six months after the treatment.

Deficiency of Parkinson’s disease-related gene Fbxo7 is associated with impaired mitochondrial metabolism by PARP activation

The Parkinson’s disease (PD)-related protein F-box only protein 7 (Fbxo7) is the substrate-recognition component of the Skp1-Cullin-F-box protein E3 ubiquitin ligase complex. We have recently shown that PD-associated mutations in Fbxo7 disrupt mitochondrial autophagy (mitophagy), suggesting a role for Fbxo7 in modulating mitochondrial homeostasis. Here we report that Fbxo7 deficiency is associated with reduced cellular NAD+ levels, which results in increased mitochondrial NADH redox index and impaired activity of complex I in the electron transport chain. Under these conditions of compromised respiration, mitochondrial membrane potential and ATP contents are reduced, and cytosolic reactive oxygen species (ROS) production is increased. ROS activates poly (ADP-ribose) polymerase (PARP) activity in Fbxo7-deficient cells. PARP inhibitor restores cellular NAD+ content and redox index and ATP pool, suggesting that PARP overactivation is cause of decreased complex I-driven respiration. These findings bring new insight into the mechanism of Fbxo7 deficiency, emphasising the importance of mitochondrial dysfunction in PD.

Redox index of soil carbon stability

As an alternative to the relatively complex and expensive spectroscopic methods, the redox properties of humic acids, determined by potentiometric titrations, have been used to evaluate the stability of soil organic C. The objective of the present study was to establish a Redox Index of C Stability (RICS) and to correlate it with some properties of the humic acids extracted from different modal soils in Brazil (distinct weathering stages or management) to facilitate system comparison. The RICS was efficient for soil comparison and variations were comparable to those of the chemical and spectroscopic methods used for humic acid characterization. The values of soil pH, point of zero salt effect, sum of bases, exchangeable Ca content, weathering index, as well as the humic acid O/C ratio, quinone and semiquinone free radical contents, aromatic C and fluorescence intensity were closely related with the RICS. The RICS was higher in less weathered soils, with more active clays and higher fertility. The RICS values of soils under long-term sugarcane management were ranked in decreasing order: unburned, burned with vinasse, burned without vinasse.

Profiling of Redox Atmosphere in Flames by Chemical Seeding/Planar Laser-Induced Fluorescence (CS/PLIF)

Knowledge on the local value of reducing and oxidizing (redox) atmospheres in flames is among the most important issues to be desired by combustion engineers. In this study, the spatial distribution of a redox atmosphere in flames has been measured experimentally by the chemical seeding/laser-induced fluorescence (CS/LIF) technique. A solution of iron was sprayed into a premixed propane-air flame supported on a slot burner. The LIF intensity of FeO band was compared to that of a Fe line to estimate the experimentally determined degree of atomization in the reaction FeO→Fe+O. The flame temperature profile was determined as a rotational temperature and was obtained by comparing the LIF (laser-induced fluorescence) intensities of OH rotational lines. The degree of atomization was theoretically calculated on the basis that simple thermal dissociation takes place in the reaction. The redox atmosphere, or a redox index, is defined as the ratio of the experimentally determined to theoretically calculated degrees of atomization. Two-dimensional distributions or profiles of the excitation temperature, experimentally determined degree of atomization, and redox index have been measured using a charge coupled device (CCD) camera fitted with an optical bandpass filter and the associated signal processing using a computer. This method has been successfully applied to quantitatively illustrate the local atmosphere and profile of the redox atmosphere in flames.