СТАНДАРТНЫЕ ЭНТАЛЬПИИ ОБРАЗОВАНИЯ В ГАЗОВОЙ ФАЗЕ И ОТНОСИТЕЛЬНАЯ УСТОЙЧИВОСТЬ ТАУТОМЕРНЫХ ФОРМ С-АЛКОКСИ-1,2,4-ТРИАЗОЛОВ И ИЗОМЕРНЫХ N-МЕТИЛ-C-МЕТОКСИ-1,2,4- ТРИАЗОЛОВ: КВАНТОВОХИМИЧЕСКОЕ ИССЛЕДОВАНИЕ

The formation enthalpies of tautomeric forms of C-alkoxy-1,2,4-triazoles (alkoxy = OCH3, OC2H5, Oi-C3H7, Ot-C4H9) and isomeric N-methyl-C-methoxy-1,2,4-triazoles have been calculated by means of designed isodesmic and isomerisation reactions. The relative Gibbs energies for their tautomeric forms and isomers in aqueous solution have been calculated. N2-tautomers and isomers of C-alkoxy-1,2,4-triazoles wеre found to have the smallest values of formation enthalpy whereas N4-forms are less stable in gaseous phase. Increasing of electron donor properties of substituent leads to the stabilization of N2-tautomers in comparison with N1-tautomers. N1- and N2-tautomers and isomers have similar values of Gibbs free energy in aqueous solution. In contrast to gaseous phase, N1-derivatives of C-methoxy- and C-ethoxy-1,2,4-triazoles as well as N-methyl-C-methoxy-1,2,4-triazoles are more stable than corresponding N2-derivatives. This is due to higher polarity of N1-isomers in comparison with N2-ones. N4-derivatives are less stable in gaseous phase as well as in aqueous solution.С использованием современных методов квантовой химии выполнены расчеты стандартных энтальпий образования в газовой фазе таутомерных форм C-алкокси-1,2,4-триазолов (алкокси = OCH3, OC2H5, Oi-C3H7, Ot-C4H9) и изомерных N-метил-C-метокси-1,2,4-триазолов путем построения изодесмических реакций и реакций изомеризации. Проведены расчеты относительных энергий Гиббса таутомерных форм и изомеров в водном растворе. Показано, что N2-таутомерные формы и N2-изомеры C-алкокси-1,2,4-триазолов характеризуются наименьшими значениями энтальпии образования, тогда как N4-формы наименее устойчивы в газовой фазе. Увеличение электронодонорных свойств заместителя приводит к большей стабилизации N2-таутомерной формы, по сравнению с соответствующим N1-таутомером. В водном растворе N1- и N2-таутомерам и изомерам соответствуют близкие значения энергии Гиббса. При этом, в отличие от газовой фазы, для C-метокси- и C-этокси-1,2,4-триазолов и N-метил-C-метокси-1,2,4-триазолов N1-производные становятся несколько более устойчивыми, чем N2-соединения, т. е. под действием полярной среды происходит обращение относительной устойчивости N1- и N2-производных по сравнению с газовой фазой. Это объясняется тем, что молекулы N1-таутомерных форм 3-алкокси-1,2,4-триазола и N1-изомеров N-алкил-3-алкокси-1,2,4-триазолов более полярны, чем молекулы соответствующих N2-соединений. Как и в газовой фазе, в водном растворе N4-производные являются наименее устойчивыми

Symbiotic Associations in the Phenotypically-Diverse Brown Alga Saccharina japonica

The brown alga Saccharina japonica (Areschoug) Lane, Mayes, Druehl et Saunders is a highly polymorphic representative of the family Laminariaceae, inhabiting the northwest Pacific region. We have obtained 16S rRNA sequence data in symbiont microorganisms of the typical form (TYP) of S. japonica and its common morphological varieties, known as “longipes” (LON) and “shallow-water” (SHA), which show contrasting bathymetric distribution and sharp morphological, life history traits, and ecological differences. Phylogenetic analysis of the 16S rRNA sequences shows that the microbial communities are significantly different in the three forms studied and consist of mosaic sets of common and form-specific bacterial lineages. The divergence in bacterial composition is substantial between the TYP and LON forms in spite of their high genetic similarity. The symbiont distribution in the S. japonica forms and in three other laminarialean species is not related to the depth or locality of the algae settlements. Combined with our previous results on symbiont associations in sea urchins and taking into account the highly specific character of bacteria-algae associations, we propose that the TYP and LON forms may represent incipient species passing through initial steps of reproductive isolation. We suggest that phenotype differences between genetically similar forms may be caused by host-symbiont interactions that may be a general feature of evolution in algae and other eukaryote organisms. Bacterial symbionts could serve as sensitive markers to distinguish genetically similar algae forms and also as possible growth-promoting inductors to increase algae productivity

КВАНТОВОХИМИЧЕСКОЕ И ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ РЕАКЦИЙ НУКЛЕОФИЛЬНОГО ЗАМЕЩЕНИЯ В РЯДУ N-АЛКИЛ-3-НИТРО-1,2,4-ТРИАЗОЛОВ

Reactions of nucleophilic substitution of nitro group in N-alkyl-3-nitro-1,2,4-triazoles have been studied both experimentally and theoretically using DFT method. The standard enthalphy and Gibbs free energy of alkoxylation reactions of N-alkyl-3-nitro-1,2,4-triazoles in gas phase and aqueous solution have been calculated. The calculation results show that nucleophilic substitution reactions of N-alkyl-3-nitro-1,2,4-triazoles with alcohols and alcoholate anions are thermodynamically possible both in gas phase and in aqueous solution. Computed activation energies for reactions of N-alkyl-3-nitro-1,2,4-triazoles with methanol decrease in the series of ΔG≠S(for 1-isomer) >> ΔG≠S(for 4-isomer) > ΔG≠S(for 2-isomer). The calculation results are in good agreement with experimental data.С использованием современных квантовохимических и экспериментальных методов исследованы процессы нуклеофильного замещения нитрогруппы в ряду N-алкил-3-нитро-1,2,4-триазолов. Проведены расчеты стандартных энтальпий и энергий Гиббса реакций алкоксилирования N-алкил-3-нитро-1,2,4-триазолов в газовой и водной фазах. Согласно выполненным расчетам, реакции нуклеофильного замещения N-алкил-3-нитро-1,2,4-триазолов со спиртами и алкоголят-анионами термодинамически возможны как в газовой фазе, так и в водном растворе. На примере изомерных N-этил-3-нитро-1,2,4-триазолов показано, что расчетные значения энергии Гиббса активации реакций с метиловым спиртом в водном растворе уменьшаются в ряду ΔG≠S(для 1-изомера) >> ΔG≠S(для 4-изомера) > ΔG≠S(для 2-изомера). Результаты расчетов хорошо согласуются с данными экспериментального исследования процессов нуклеофильного замещения нитрогруппы в молекулах N-алкил-3-нитро-1,2,4-триазолов

The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database

Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe

Energetic Materials Based on <i>N</i>-substituted 4(5)-nitro-1,2,3-triazoles

The regularities and synthetic potentialities of the alkylation of 4(5)-nitro-1,2,3-triazole in basic media were explored, and new energetic ionic and nitrotriazole-based coordination compounds were synthesized in this study. The reaction had a general nature and ended with the formation of N1-, N2-, and N3-alkylation products, regardless of the conditions and reagent nature (alkyl- or aryl halides, alkyl nitrates, dialkyl sulfates). This reaction offers broad opportunities for expanding the variability of substituents on the nitrotriazole ring in the series of primary and secondary aliphatic, alicyclic, and aromatic substituents, which is undoubtedly crucial for solving the problems related to both high-energy materials development and medicinal chemistry when searching for new efficient bioactive compounds. An efficient methodology for the separation of regioisomeric N-alkyl(aryl)nitrotriazoles has been devised and relies on the difference in their basicity and reactivity during quaternization and complexation reactions. Based on the inaccessible N3-substitution products that exhibit a combination of properties of practical importance, a series of energy-rich ionic systems and coordination compounds were synthesized that are gaining ever-increasing interest for the chemistry of energy-efficient materials, coordination chemistry, and chemistry of ionic liquids