Антиоксидантна активність піридилгідразонів ароматичних альдегідів

The kinetic parameters of the antioxidant activity of pyridylhydrazones derivatives of aromatic aldehydes in the initiated oxidation of ethylbenzene have been determined by the chemiluminescent method. The antioxidants studied have higher values of the reaction rate constants with peroxy radicals k7 compared to ionol. In the conditions of autooxidation of ethylbenzene the efficiency of the antioxidants studied reduces. It has been found that 3-pyridylhydrazon-3,5-dimethyl-4-hydroxybenzaldehyde interacts with cumene hydroperoxide. The regularities of the inhibitory effect of pyridylhydrazones in heterogeneous systems have been studied. Interaction of pyridylhydrazones with НО• radicals has been investigated by the chemiluminescent method in water solution. It has been determined that pyridylhydrazones show a high activity towards НО• radicals. In the initiated azodiisobutyronitrile oxidation the emulsion of ethylbenzene : water derivative of pyridylhydrazones has revealed a high antioxidant activity. In the presence of hydrophobic derivatives in molecules of antioxidants the values of log P and the induction period (τ/τ0) increase. When inhibiting the initiated oxidation of phosphatidylcholine dispersion pyridylhydrazones show practically twice higher antioxidant activity in comparison with ionol.Определены кинетические параметры антиоксидантной активности производных пиридилгидразонов ароматических альдегидов при инициированном окислении этилбензола хемилюминесцентным методом. Исследованные антиоксиданты имеют более высокие значения констант скорости реакции с пероксирадикалами k7 по сравнению с ионолом. В условиях высокотемпературного автоокисления этилбензола эффективность пиридилгидразонов снижается. Установлено, что 3-пиридилгидразон-3,5- диметил-4-гидроксибензальдегида взаимодействует с гидропероксидом кумила. Хемилюминесцентным методом показано, что пиридилгидразоны проявляют высокую активность по отношению к НО• радикалам в водном растворе. Изучены закономерности ингибирующего действия пиридилгидразонов в гетерогенных системах. Установлена зависимость антиокислительной активности гидразонов от значений показателей липофильности антиоксидантов. При ингибировании инициированного окисления дисперсии фосфатидилхолина пиридилгидразоны проявляют практически вдвое большую антиоксидантную активность по сравнению с ионолом. Визначені кінетичні параметри антиоксидантної активності похідних піридилгідразонів ароматичних альдегідів при ініційованому окисненні етилбензолу хемілюмінесцентним методом. Досліджені антиоксиданти мають більші значення констант швидкості реакції з пероксильними радикалами k7 у порівнянні з іонолом. В умовах високотемпературного автоокиснення етилбензолу ефективність досліджених антиоксидантів знижується. Встановлено, що 3-піридилгідразон-3,5-диметил-4-гідроксибензальдегіду взаємодіє з гідропероксидом кумілу. Хемілюмінесцентним методом показано, що піридилгідразони виявляють високу активність щодо НО• радикалів у водному розчині. Вивчені закономірності інгібуючої дії піридилгідразонів у гетерогенних системах. Встановлено залежність антиокиснювальної активності гідразонів від значень показників ліофільності антиоксидантів. При інгібуванні ініційованого окиснення дисперсії фосфатидилхоліну піридилгідразони проявляють практично вдвічі більшу АОА, ніж іонол

Curvature properties of ϕ\phi-null Osserman Lorentzian S\mathcal{S}-manifolds

We expound some results about the relationships between the Jacobi operators with respect to null vectors on a Lorentzian $\mathcal{S}$-manifold $M$ and the Jacobi operators with respect to particular spacelike unit vectors on $M$. We study the number of the eigenvalues of such operators in a $\phi$-null Osserman Lorentzian $\mathcal{S}$-manifold, under suitable assumptions on the dimension of the manifold. Then, we generalize a curvature characterization, previously obtained by the first author for Lorentzian $\phi$-null Osserman $\mathcal{S}$-manifolds with exactly two characteristic vector fields, to the case of those with an arbitrary number of characteristic vector fields.Comment: 15 pages; signs corrected on page 8, reference adde

Performance of the Genotype® MTBDRPlus assay in the diagnosis of tuberculosis and drug resistance in Samara, Russian Federation

<p>Abstract</p> <p>Background</p> <p>Russia is a high tuberculosis (TB) burden country with a high prevalence of multidrug resistant tuberculosis (MDRTB). Molecular assays for detection of MDRTB on clinical specimens are not widely available in Russia.</p> <p>Results</p> <p>We performed an evaluation of the GenoType^®MTBDRplus assay (HAIN Lifescience GmbH, Germany) on a total of 168 sputum specimens from individual patients at a public health laboratory in Central Russia, as a model of a middle income site in a region with high levels of drug resistance. Phenotypic drug resistance tests (DST) were performed on cultures derived from the same sputum specimens using the BACTEC 960 liquid media system.</p> <p>Interpretable GenoType^®MTBDRplus results were obtained for 154(91.7%) specimens with readability rates significantly higher in sputum specimens graded 2+ and 3+ compared to 1+ (RR = 1.17 95%CI 1.04–1.32). The sensitivity and specificity of the assay for the detection of rifampicin (RIF) and isoniazid (INH) resistance and MDR was 96.2%, 97.4%, 97.1% and 90.7%, 83.3%, 88.9% respectively. Mutations in codon 531 of the <it>rpoB </it>gene and codon 315 of the <it>katG </it>gene dominated in RIF and INH resistant strains respectively. Disagreements between phenotypical and molecular tests results (12 samples) could be explained by the presence of rare mutations in strains circulating in Russia and simultaneous presence of resistant and sensitive bacilli in sputum specimens (heteroresistance).</p> <p>Conclusion</p> <p>High sensitivity, short turnaround times and the potential for screening large numbers of specimens rapidly, make the GenoType^®MTBDRplus assay suitable as a first-line screening assay for drug resistant TB.</p

An Integrated Approach to Rapid Diagnosis of Tuberculosis and Multidrug Resistance Using Liquid Culture and Molecular Methods in Russia

Objective: To analyse the feasibility, cost and performance of rapid tuberculosis (TB) molecular and culture systems, in a high multidrug-resistant TB (MDR TB) middle-income region (Samara, Russia) and provide evidence for WHO policy change. Methods: Performance and cost evaluation was conducted to compare the BACTEC™ MGIT™ 960 system for culture and drug susceptibility testing (DST) and molecular systems for TB diagnosis, resistance to isoniazid and rifampin, and MDR TB identification compared to conventional Lowenstein-Jensen culture assays. Findings: 698 consecutive patients (2487 sputum samples) with risk factors for drug-resistant tuberculosis were recruited. Overall M. tuberculosis complex culture positivity rates were 31.6% (787/2487) in MGIT and 27.1% (675/2487) in LJ (90.5% and 83.2% for smear-positive specimens). In total, 809 cultures of M. tuberculosis complex were isolated by any method. Median time to detection was 14 days for MGIT and 36 days for LJ (10 and 33 days for smear positive specimens) and indirect DST in MGIT took 9 days compared to 21 days on LJ. There was good concordance between DST on LJ and MGIT (96.8% for rifampin and 95.6% for isoniazid). Both molecular hybridization assay results correlated well with MGIT DST results, although molecular assays generally yielded higher rates of resistance (by approximately 3% for both isoniazid and rifampin). Conclusion: With effective planning and logistics, the MGIT 960 and molecular based methodologies can be successfully introduced into a reference laboratory setting in a middle incidence country. High rates of MDR TB in the Russian Federation make the introduction of such assays particularly useful. © 2009 Balabanova et al