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1
Insuasty, Alberto, Carmen Atienza, Juan Luis López und Nazario Martín. „Supramolecular pentapeptide-based fullerene nanofibers: effect of molecular chirality“. Chemical Communications 51, Nr. 52 (2015): 10506–9. http://dx.doi.org/10.1039/c5cc01991e.
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The supramolecular organization of new fullerene derivatives endowed with peptides as biomolecular templates affords ordered nanofibers of several micrometres length based on hydrogen bonds and π–π interactions.
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Kosonen, Harri, Janne Ruokolainen, Matti Knaapila, Mika Torkkeli, Kaija Jokela, Ritva Serimaa, Gerrit ten Brinke, Wim Bras, Andrew P. Monkman und Olli Ikkala. „Nanoscale Conducting Cylinders Based on Self-Organization of Hydrogen-Bonded Polyaniline Supramolecules“. Macromolecules 33, Nr. 23 (November 2000): 8671–75. http://dx.doi.org/10.1021/ma0010783.
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3
Luo, Dan, Boyang Zhou, Zhenxing Li, Xiaoyun Qin, Yangyang Wen, Dongdong Shi, Qiong Lu, Meiyan Yang, Hongjun Zhou und Yan Liu. „Biomimetic organization of a ruthenium-doped collagen-based carbon scaffold for hydrogen evolution“. Journal of Materials Chemistry A 6, Nr. 5 (2018): 2311–17. http://dx.doi.org/10.1039/c7ta09493k.
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Tsiourvas, Dimitris, Constantinos M. Paleos, Jane Anastassopoulou und Theophile Theophanides. „Vibrational Spectroscopy of Certain Polymaleic- and Polyacrylic-Based Mesomorphic Polymers“. Applied Spectroscopy 49, Nr. 9 (September 1995): 1311–16. http://dx.doi.org/10.1366/0003702953965272.
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The FT-IR/ATR technique has been employed in the investigation of the forces leading to the organization of a number of polymeric materials exhibiting thermotropic liquid crystalline character. Two types of compounds have been studied, i.e., one bearing the carboxylic polar group near the main chain and the other at the end of the side chain. Intermolecular and intramolecular hydrogen bonding between the carboxylic groups was found to lead to the formation of “facing” and “sideways” structures. Enhanced stability of these supramolecular structures was obtained by the presence of intramolecular hydrogen bonds between the amide groups, resulting in the formation of smectic phases. Furthermore, it has been found that the strengthening of hydrogen bonding between carboxylic groups is associated with a weakening of hydrogen bonds between the amide groups.
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Sabury, Sina, Tyler J. Adams, Margaret Kocherga, S. Michael Kilbey und Michael G. Walter. „Synthesis and optoelectronic properties of benzodithiophene-based conjugated polymers with hydrogen bonding nucleobase side chain functionality“. Polymer Chemistry 11, Nr. 36 (2020): 5735–49. http://dx.doi.org/10.1039/d0py00972e.
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Nucleobase functionalities in conjugated, alternating copolymers participate in interbase hydrogen bonding, which promotes molecular assembly and organization in thin films and enhances optical and electronic properties.
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Shi, Dong, Wen-Ying Chang, Xiang-Kui Ren, Shuang Yang und Er-Qiang Chen. „Structures and properties of side-chain liquid crystalline polynorbornenes containing an amide group: hydrogen bonding interactions and spacer length effects“. Polymer Chemistry 11, Nr. 29 (2020): 4749–59. http://dx.doi.org/10.1039/d0py00586j.
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Side-chain liquid crystalline polynorbornenes based on benzanilide mesogens exhibit rich self-organization behaviours and enhanced mechanical properties owing to the lateral hydrogen bond interaction that can be tuned by the spacer length.
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Toleukhanov, А., М. Panfilov und А. Kаltayev. „Analytical and Numerical Study of the Impact of Methanogenic Bacteria on Gas Composition in Underground Hydrogen Storages“. Eurasian Chemico-Technological Journal 17, Nr. 3 (13.07.2015): 243. http://dx.doi.org/10.18321/ectj250.
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Unlike natural gas, hydrogen gas mixtures stored in underground reservoirs undergo active chemical transformations under the influence of methanogenic microorganisms inhabiting in porous reservoirs. They lead to reduction of hydrogen and carbon dioxide concentrations and increase methane concentration. This chemical activity coupled with bacterial dynamics and gas/water flow through porous medium causes the phenomenon of self-organization such as the occurrence of autowave spatial structures, whose dynamics is characterized by a multiplicity of scenarios and bifurcations between them. In this paper we continue to develop the qualitative theory of self-organization in underground hydrogen storage, for more complicated cases that include the mechanism of chemotaxis, which is one of the main types of bacterial movement, and takes into account the flow of both phases. The analysis of scenarios is based on the model of two-phase compositional flow coupled with population dynamics.
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Victoria Martínez-Díaz, M., und Giovanni Bottari. „Supramolecular organization of phthalocyanines: from solution to surface“. Journal of Porphyrins and Phthalocyanines 13, Nr. 04n05 (April 2009): 471–80. http://dx.doi.org/10.1142/s1088424609000747.
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Phthalocyanines are an interesting class of aromatic macrocycles which possess exciting electrical, redox and photophysical properties that make them ideal building blocks for applications in different technological fields. However, the incorporation of phthalocyanines into devices is often tied to the possibility of organizing these macrocycles into arrays using supramolecular interactions. To date, several supramolecular motifs such as hydrogen-bonding, donor-acceptor or metal-ligand interactions have been used to promote the phthalocyanines' organization in solution. Furthermore, such weak, non-covalent interactions have also been widely employed to foster the organization of these macrocycles in condensed phases such as liquid-crystals or thin films. This micro-review provides a brief overview of the contribution made by some research groups in Spain towards the preparation of organized phthalocyanine-based supramolecular systems.
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Marchi, M. Claudia, Carlos A. Figueroa und Fernando Alvarez. „Functionalization of Ordered Iron-Based Nanoparticles Deposited on Mesoporous Films“. Journal of Nanoscience and Nanotechnology 8, Nr. 1 (01.01.2008): 448–51. http://dx.doi.org/10.1166/jnn.2008.045.
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Mesoporous films obtained by dip-coating, combining polycondensation of silicate species and organization of amphiphilic mesophases, were decorated with iron-based nanoparticles from iron aqueous solution. High-resolution transmission electron microscopy (HR-TEM) images and energy dispersive X-rays spectroscopy (EDS) analysis show that the nanoparticles have diameters between 5 to 10 nm and they are deposited in an ordered sequence exclusively on top of the mesoporous structure. Afterward, by irradiating the material with a hydrogen ion beam, the iron-based compound is functionalized, i.e., its physical-chemical properties are modified. X-ray photoelectron spectroscopy (XPS) showed that the iron oxides and hydroxides are reduced to metallic iron. The deposition of organized iron-based nanoparticles and further ion beam functionalization might open perspectives on the study and fabrication of complex new materials.
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Mezentsev-Cherkes, Ivan A., Tatiana A. Shestimerova, Aleksei V. Medved'ko, Mikhail A. Kalinin, Alexey N. Kuznetsov, Zheng Wei, Evgeny V. Dikarev, Sergey Z. Vatsadze und Andrei V. Shevelkov. „Synthesis and supramolecular organization of the iodide and triiodides of a polycyclic adamantane-based diammonium cation: the effects of hydrogen bonds and weak I⋯I interactions“. CrystEngComm 23, Nr. 12 (2021): 2384–95. http://dx.doi.org/10.1039/d0ce01730b.
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Adamantane-like divalent building blocks and iodide or polyiodide anions combine into supramolecular architectures with the help of various noncovalent forces ranging from strong hydrogen bonds to secondary and weak I⋯I interactions.
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Sabater i Serra, Roser, José Molina-Mateo, Constantino Torregrosa-Cabanilles, Andreu Andrio-Balado, José María Meseguer Dueñas und Ángel Serrano-Aroca. „Bio-Nanocomposite Hydrogel Based on Zinc Alginate/Graphene Oxide: Morphology, Structural Conformation, Thermal Behavior/Degradation, and Dielectric Properties“. Polymers 12, Nr. 3 (22.03.2020): 702. http://dx.doi.org/10.3390/polym12030702.
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Bio-nanocomposite hydrogels based on sodium alginate (SA) as polymer matrix and graphene oxide (GO) nanosheets with zinc as crosslinking agent were synthesized with the aim of incorporating the intrinsic properties of their constituents (bioactivity and antimicrobial activity). Thus, stable and highly interconnected networks were obtained from GO nanosheets dispersed in SA matrices through interactions with low amounts of zinc. The GO nanosheets were successfully incorporated into the alginate matrix in the form of a complex nano-network involving different interactions: Bonds between alginate chains induced by Zn ions (egg box structure), interactions between GO nanosheets through Zn ions and hydrogen bonds between alginate chains, and GO nanosheets. The molecular interactions and morphology were confirmed by Fourier-transform infrared spectroscopy and transmission electron microscopy. The composite’s structural organization showed enhanced thermal stability. The glass transition temperature shifted to a higher temperature due to the reduced mobility induced by additional crosslinking bonds after incorporating the GO nanosheets and Zn into the polymer matrix. Finally, the dielectric behavior revealed that charge carrier mobility was hampered by the compact structure of the nanonetwork, which reduced conductivity. The combined properties of these nanocomposite hydrogels make them attractive biomaterials in the field of regenerative medicine and wound care since both surface bioactivity and antibacterial behavior are two critical factors involved in the success of a biomaterial.
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Bannister, R. L., R. A. Newby und W. C. Yang. „Development of a Hydrogen-Fueled Combustion Turbine Cycle for Power Generation“. Journal of Engineering for Gas Turbines and Power 120, Nr. 2 (01.04.1998): 276–83. http://dx.doi.org/10.1115/1.2818116.
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Consideration of a hydrogen based economy is attractive because it allows energy to be transported and stored at high densities and then transformed into useful work in pollution-free turbine or fuel cell conversion systems. Through its New Energy and Industrial Technology Development Organization (NEDO) the Japanese government is sponsoring the World Energy Network (WE-NET) Program. The program is a 28-year global effort to define and implement technologies needed for a hydrogen-based energy system. A critical part of this effort is the development of a hydrogen-fueled combustion turbine system to efficiently convert the chemical energy stored in hydrogen to electricity when the hydrogen is combusted with pure oxygen. The full-scale demonstration will be a greenfield power plant located seaside. Hydrogen will be delivered to the site as a cryogenic liquid, and its cryogenic energy will be used to power an air liquefaction unit to produce pure oxygen. To meet the NEDO plant thermal cycle requirement of a minimum of 70.9 percent, low heating value (LHV), a variety of possible cycle configurations and working fluids have been investigated. This paper reports on the selection of the best cycle (a Rankine cycle), and the two levels of technology needed to support a near-term plant and a long-term plant. The combustion of pure hydrogen with pure hydrogen with pure oxygen results only in steam, thereby allowing for a direct-fired Rankine steam cycle. A near-term plant would require only development to support the design of an advanced high pressure steam turbine and an advanced intermediate pressure steam turbine.
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Bannister, R. L., R. A. Newby und W. C. Yang. „Final Report on the Development of a Hydrogen-Fueled Combustion Turbine Cycle for Power Generation“. Journal of Engineering for Gas Turbines and Power 121, Nr. 1 (01.01.1999): 38–45. http://dx.doi.org/10.1115/1.2816310.
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Through its New Energy and Industrial Technology Development Organization (NEDO) the Japanese government is sponsoring the World Energy Network (WE-NET) Program. WE-NET is a 28-year global effort to define and implement technologies needed for hydrogen-based energy systems. A critical part of this effort is the development of a hydrogen-fueled combustion turbine system to efficiently convert the chemical energy stored in hydrogen to electricity when hydrogen is combusted with pure oxygen. A Rankine cycle, with reheat and recuperation, was selected by Westinghouse as the general reference system. Variations of this cycle have been examined to identify a reference system having maximum development feasibility, while meeting the requirement of a minimum of 70.9 percent low heating value (LHV) efficiency. The strategy applied by Westinghouse was to assess both a near-term and long-term Reference Plant. The near-term plant requires moderate development based on extrapolation of current steam and combustion turbine technology. In contrast, the long-term plant requires more extensive development for an additional high pressure reheat turbine, and is more complex than the near-term plant with closed-loop steam cooling and extractive feedwater heating. Trade-offs between efficiency benefits and development challenges of the near-term and long-term reference plant are identified. Results of this study can be applied to guide the future development activities of hydrogen-fueled combustion turbine systems.
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Gaskin, Sharyn, Linda Heath, Dino Pisaniello, Richard Evans, John W. Edwards, Michael Logan und Christina Baxter. „Hydrogen sulphide and phosphine interactions with human skin in vitro“. Toxicology and Industrial Health 33, Nr. 4 (09.07.2016): 289–96. http://dx.doi.org/10.1177/0748233716630646.
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Accidental or intentional releases of toxic gases can have significant public health consequences and emergency resource demands. Management of exposed individuals during hazardous material incidents should be risk and evidence based, but there are knowledge gaps in relation to dermal absorption of gases and management advice for potentially exposed individuals. Using a modified Organization for Economic Co-operation and Development (OECD) in vitro toxicology protocol with human donor skin, this article reports on two common and odorous chemicals, hydrogen sulphide and phosphine. Results show that undamaged human skin provides a good barrier to hydrogen sulphide (up to 800 ppm) and phosphine (up to 1000 ppm) penetration for up to 30 min exposures, with little variability in the presence of clothing or in elevated temperature and humidity conditions. A practical guideline template for skin decontamination has been developed, and implications of the research for first responders are outlined.
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Korlyukov, Alexander, Anna Vologzhanina, Evgenia Voronova, Natalia Shmatkova und Inna Seifullina. „Supramolecular organization of complexes of aryl hydrazones with SnCl3and SnCl4“. Acta Crystallographica Section A Foundations and Advances 70, a1 (05.08.2014): C657. http://dx.doi.org/10.1107/s2053273314093425.
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Chelate complexes of main group metals with N,O-chelating Schiff Base ligands have been reported as perspective models for biologically active species. The derivatives of aryl hydrazones are among the most widely used ligands of such type. In our study, crystal structures of aryl hydrazones with SnCl3and SnCl4are discussed: the presence of aromatic fragments, amine groups and chlorine atoms therein are responsible for the coexistence of strong hydrogen and halogen bonds as well as stacking and Cl...π interactions. Interplay between these types of interactions and their role in stabilization of crystal structures is the subject of particular interest. We studied all these aspects in complexes of aryl hydrazones using different theoretical approaches: those based on Stockholder partitioning, molecular electrostatic potential, non-covalent interaction index, AIM theory – together with Espinosa-Mollins-Lecomte correlation to estimate the energy of all intermolecular interactions in crystals by means of electron density analysis from periodic quantum chemical calculations (VASP code). Our results showed that the presence of intermolecular interactions led to a noticeable redistribution of electron density in crystal as compared to an isolated molecule. Although Cl...π, stacking interactions and halogen bonds are numerous in the crystals of these complexes, their contribution to the energy of their crystal lattice does not exceed 30%. The work was supported by Council of the President of the Russian Federation (grant MD-3589.2014.3).
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Jung, Julie, Olivier Cador, Kevin Bernot, Fabrice Pointillart, Javier Luzon und Boris Le Guennic. „Influence of the supramolecular architecture on the magnetic properties of a DyIII single-molecule magnet: an ab initio investigation“. Beilstein Journal of Nanotechnology 5 (27.11.2014): 2267–74. http://dx.doi.org/10.3762/bjnano.5.236.
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Single-crystal angular-resolved magnetometry and wavefunction-based calculations have been used to reconsider the magnetic properties of a recently reported DyIII-based single-molecule magnet, namely [Dy(hfac)3(L1)] with hfac− = 1,1,1,5,5,5-hexafluoroacetylacetonate and L1 = 2-(4,5-bis(propylthio)-1,3-dithiol-2-ylidene)-6-(pyridin-2-yl)-5H-[1,3]dithiolo[4',5':4,5]benzo[1,2-d]imidazole. The magnetic susceptibility and magnetization at low temperature are found to be strongly influenced by supramolecular interactions. Moreover, taking into account the hydrogen-bond networks in the calculations allows to explain the orientation of the magnetic axes. This strongly suggests that hydrogen bonds play an important role in the modulation of the electrostatic environment around the DyIII center that governs the nature of its magnetic ground-state and the orientation of its anisotropy axes. We thus show here that SMM properties that rely on supramolecular organization may not be transferable into single-molecule devices.
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Shishkina, Svitlana V., Irina S. Konovalova, Pavlo V. Trostianko, Anna O. Geleverya, Sergiy M. Kovalenko und Natalya D. Bunyatyan. „Three polymorphs of 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzopyran-2-one formed from different solvents“. Acta Crystallographica Section C Structural Chemistry 75, Nr. 6 (29.05.2019): 822–32. http://dx.doi.org/10.1107/s2053229619006405.
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The polymorphic study of 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzopyran-2-one, C17H11N3O2, was performed due to its potential biological activity and revealed three polymorphic modifications in the triclinic space group P\overline{1}, the monoclinic space group P21 and the orthorhombic space group Pbca. These polymorphs have a one-column layered type of crystal organization. The strongest interactions between the molecules of the studied structures is stacking between π-systems, while N—H...N and C—H...O hydrogen bonds link stacked columns forming layers as a secondary basic structural motif. C—H...π hydrogen bonds were observed between neighbouring layers and their role is the least significant in the formation of the crystal structure. Packing differences between the polymorphic modifications are minor and can be identified only using an analysis based on a comparison of the pairwise interaction energies.
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Wulf, Christina, Petra Zapp, Andrea Schreiber und Wilhelm Kuckshinrichs. „Setting Thresholds to Define Indifferences and Preferences in PROMETHEE for Life Cycle Sustainability Assessment of European Hydrogen Production“. Sustainability 13, Nr. 13 (22.06.2021): 7009. http://dx.doi.org/10.3390/su13137009.
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The Life Cycle Sustainability Assessment (LCSA) is a proven method for sustainability assessment. However, the interpretation phase of an LCSA is challenging because many different single results are obtained. Additionally, performing a Multi-Criteria Decision Analysis (MCDA) is one way—not only for LCSA—to gain clarity about how to interpret the results. One common form of MCDAs are outranking methods. For these type of methods it becomes of utmost importance to clarify when results become preferable. Thus, thresholds are commonly used to prevent decisions based on results that are actually indifferent between the analyzed options. In this paper, a new approach is presented to identify and quantify such thresholds for Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE) based on uncertainty of Life Cycle Impact Assessment (LCIA) methods. Common thresholds and this new approach are discussed using a case study on finding a preferred location for sustainable industrial hydrogen production, comparing three locations in European countries. The single LCSA results indicated different preferences for the environmental, economic and social assessment. The application of PROMETHEE helped to find a clear solution. The comparison of the newly-specified thresholds based on LCIA uncertainty with default thresholds provided important insights of how to interpret the LCSA results regarding industrial hydrogen production.
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Аверкин, Дмитрий Вадимович, Дмитрий Викторович Вишневецкий, Владимир Романович Петров, Светлана Дмитриевна Хижняк und Павел Михайлович Пахомов. „THE PROCESS OF SELF-ORGANIZATION IN LOW-CONCENTRATED AQUEOUS SYSTEMS BASED ON N-ACETYL-L-CYSTEINE, L-CYSTEINE AND SILVER ACETATE“. Вестник Тверского государственного университета. Серия: Химия, Nr. 4(42) (21.12.2020): 70–82. http://dx.doi.org/10.26456/vtchem2020.4.8.
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Проведено комплексное исследование процесса самоорганизации при сливании низкоконцентрированных водных растворов N-ацетил-L-цистеина и ацетата серебра. Все стадии самоорганизации изучены c помощью измерения величины рН, методов вискозиметрии, УФ спектроскопии и динамического светорассеяния (ДСР). Установлено, что началом самосборки является замена водорода в меркаптогруппе аминокислоты на катион серебра с образованием молекулы меркаптида серебра (МС). Далее происходит образование цепочек вида (-Ag-S(NCys)-Ag-S(NCys)-), при этом происходит протонирование аминокислотных остатков N-ацетил-L-цистеина. Предложен механизм самоорганизации в водном растворе N-ацетил-L-цистеина и ацетата серебра (N-ацетилцистеин-серебряный раствор - НАЦ), заключающийся в образовании агрегатов типа «ядро-оболочка». «Ядро» агрегатов состоит из цепочек вида (-Ag-S(NCys)-Ag-S(NCys)-), «оболочка» агрегатов состоит из протонированных аминокислотных остатков. Связывание таких агрегатов происходит посредством образования связей с ацетат-анионами. A comprehensive study of the self-organization process during the draining of low-concentration aqueous solutions of N-acetyl-L-cysteine and silver acetate was carried out. All stages of self-organization have been studied using pH measurements, viscometry, UV spectroscopy, and dynamic light scattering (DLS). It was found that the first stage of self-assembly is the replacement of hydrogen in the mercapto group of an amino acid with a silver cation with the formation of a silver mercaptide (MS) molecule. Further, the formation of chains of the form (-Ag-S(NCys)-Ag-S(NCys)-) occurs, while excess electron density is retained in amino acid residues, leading to the interaction of chains with both silver cations and undissociated silver acetate molecules , with the formation of clusters. The mechanism of self-organization of the system as the formation of the aggregates of the «core-shell» type is proposed. The «core» consists of chains of the form (-Ag-S(NCys)-Ag-S(NCys)-), the «shell» consists of protonated N-acetyl-L-cysteine resides. Further bonding of aggregates into clusters occurs through free acetic acid anions.
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Szymczak, Pat Davis. „World’s Largest Gas-Producing Nations: Natural Gas Will Keep the Lights on for the Next Generation“. Journal of Petroleum Technology 73, Nr. 04 (01.04.2021): 18–21. http://dx.doi.org/10.2118/0421-0018-jpt.
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Natural gas is almost certain to be the fastest-growing fossil fuel in the global energy mix for decades to come, comprising 28% of the global energy mix by 2050. Together with renewables, natural gas will likely fuel 60% of global electricity production, be it as pipeline gas, liquefied natural gas (LNG), or blue hydrogen. These are among the forecasts that appear in the 2020 edition of the GECF (Gas Exporting Countries Forum) Global Gas Outlook 2050 released in February 2021 and providing short-, medium-, and long-term energy projections based on assumptions regarding macroeconomic conditions, energy prices, and policies. The report is updated yearly and is the flagship publication of the organization, which represents countries that control 71% of global gas reserves. It is unique in that it focuses exclusively on the global gas industry, which today is providing for 23% of global energy needs. Headquartered in Doha, Qatar, the GECF is an intergovernmental organization comprising 11 member countries and nine observer states, established in 2001 by Russia and Iran. Moscow and Tehran had hoped that GECF would eventually morph into a “Gas OPEC” but that never happened. The organization’s analyses and forecasts do, however, present a worthwhile snapshot of how the world’s largest gas producers see the industry. Member states in GECF include Algeria, Bolivia, Egypt, Equatorial Guinea, Iran, Libya, Nigeria, Qatar, Russia, Trinidad and Tobago, and Venezuela. Observer countries are Angola, Azerbaijan, Iraq, Kazakhstan, Malaysia, Norway, Oman, Peru, and the UAE. Unconventional Gas To Play Growing Role In its report, the GECF noted that unconventional resources will be playing a growing role in the market and that gas producers will need to emphasize unconventional projects to satisfy growing demand, as well as to invest heavily into exploration to identify and tap into new gas reserves and develop greenfield projects. “It is also important to highlight the increasing interest in hydrogen as a lever to support the deep decarbonization of the world’s economies,” Yury P. Sentyurin, GECF’s Secretary General, wrote in his introduction to the annual outlook. In mentioning hydrogen, Sentyurin is speaking about “blue hydrogen” which is produced from natural gas, and which, when combined with CCUS (carbon capture, utilization, storage) can marry commercial and environmental interests, further positioning natural gas as a transition fuel to bridge the gap between fossil fuels and renewable sources of energy. Blue hydrogen is in fact expected to satisfy half of the hydrogen demand projected worldwide by 2050, Sentyurin points out. Policies being set by countries in the European Union have focused more on costly “green hydrogen” produced from renewable sources; but not in the policies of other nations in regions of the world where growth in energy demand is expected to be the highest. Growth in European energy demand is largely flat.
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Sergeev, N. N., A. N. Sergeev, S. N. Kutepov, A. E. Gvozdev und E. V. Ageev. „A REVIEW OF THEORECTICAL CONCEPTS OF HYDROGEN CRACKING IN METALS AND ALLOYS“. Proceedings of the Southwest State University 21, Nr. 3 (28.06.2017): 6–33. http://dx.doi.org/10.21869/2223-1560-2017-21-3-6-33.
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Today the demand for high-strength metal materials to be used in critical structural elements and facilities that operate under variable temperature and stress conditions is steadily growing economic and engineering tendency. However increased strength features of a metal are opposed by its reduced plasticity so the metal often becomes unfit for large plastic straining. In this case solid body brittle failure starts and this process is quite often of random character, which may result in big financial loss and human injuries. Available literature contains little information on delayed failure issues in principle, however, many research findings demonstrate that the decisive role in this process belongs to hydrogen that interacts with different types of micro-defects in the matrice. In order to understand why a more easy propagation of dislocations from the crack tip down results in embrittlement it is necessary to study the crack growth pattern in inert media for plastic materials. Common features of different hydrogen embrittlement processes make it possible to conclude that a solid theory should be based on consolidated concepts of hydrogen-induced failures with taking into account the synergism of metal-hydrogen systems, i.e. the change in embrittlement mechanism in the process of the material structural self-organization at different structure-scale levels. Here a very important issue is to investigate the response of the material fine structure (structural relaxation) to the influence of a hydrogen medium under various straining temperature and speed conditions. Such investigation should be conducted with the help of electronic microscopes by applying acoustical emission and inner friction methods. Thanks to them it is possible to study the auto-wave nature of metal plastic deformation and to identify the most typical sustainable dissipative structures that emerge during the material self-organizing under combined impact of tensile stress and corrosive media.
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Kechin, Alexander V., Alexander V. Levin, Sergei P. Khaliutin und Boris V. Zhmurov. „ORGANIZATION OF POWER SUPPLY OF THE FIRST CATEGORY RECEIVERS FOR PERSPECTIVE CIVIL AVIATION AIRCRAFT“. Civil Aviation High TECHNOLOGIES 21, Nr. 6 (26.12.2018): 54–64. http://dx.doi.org/10.26467/2079-0619-2018-21-6-54-64.
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The article deals with the issue of providing electric power to the first category receivers in the emergency mode of the power supply systems operation of perspective and modernized aircraft. The analysis of the published scientific works performed both in Russia and abroad, and aimed at solving problems of analyzing abnormal operations mode, synthesizing power supply systems and controlling them in order to prevent dangerous consequences is carried out. The authors considered the ingenious technical solutions aimed at providing the necessary quality power supply for the first category receivers in the emergency operation modes of the aircraft power supply systems for the safe completion of flight and landing. The research analysis and generalization of data on the technical characteristics of units and devices developed by the world's leading manufacturers of aviation equipment and used as emergency sources of electrical power on board modern civil aviation aircraft has been completed. The advantages and disadvantages of each technical solution are determined, as well as limitations to the area of their application are formed. The analysis of perspective emergency sources of the electric power including those, which previously were not applied in aviation because of their insufficient technical perfection, for example, hydrogen electrochemical generators is carried out. Based on the performed analysis, a solution which allows improving the operating modes of the electrical batteries is proposed. The offered solution makes it possible to increase the reliability and durability of electrical batteries, as well as the power supply duration of the first category receivers from them.
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Matienko, Ludmila, Mil Elena Mickhailovna, Binyukov Vladimir Ivanovich und Goloshchapov Alexandr Nikolaevich. „AFM Research in Catalysis and Medicine“. Current Organocatalysis 7, Nr. 3 (30.11.2020): 248–55. http://dx.doi.org/10.2174/2213337207999200717171645.
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Background: In this study, we show that the AFM method not only allows monitoring the morphological changes in biological structures fixed on the surface due to H-bonds, but also makes it possible to study the self-organization of metal complexes by simulating the active center of enzymes due to intermolecular H-bonds into stable nanostructures; the sizes of which are much smaller than the studied biological objects. The possible role of intermolecular hydrogen bonds in the formation of stable supramolecular metal complexes, which are effective catalysts for the oxidation of alkyl arenes to hydroperoxides by molecular oxygen and mimic the selective active sites of enzymes, was first studied by AFM. Methods and Results: The formation of supramolecular structures due to intermolecular hydrogen bonds and, possibly, other non-covalent interactions, based on homogenous catalysts and models of active centers enzymes, heteroligand nickel and iron complexes, was proven by AFM-technique. AFM studies of supramolecular structures were carried out using NSG30 cantilever with a radius of curvature of 2 nm, in the tapping mode. To form nanostructures on the surface of a hydrophobic, chemically modified silicon surface as a substrate, the sample was prepared using a spin-coating process from solutions of the nickel and iron complexes. The composition and the structure of the complex Ni2(acac)(OAc)3·NMP·2H2O were determined in earlier works using various methods: mass spectrometry, UV- and IR-spectroscopy, elemental analysis, and polarography. Self-assembly of supramolecular structures is due to intermolecular interactions with a certain coordination of these interactions, which may be a consequence of the properties of the components themselves, the participation of hydrogen bonds and other non-covalent interactions, as well as the balance of the interaction of these components with the surface. Using AFM, approaches have been developed for fixing on the surface and quantifying parameters of cells. Conclusion: This study summarizes the authors' achievements in using the atomic force microscopy (AFM) method to study the role of intermolecular hydrogen bonds (and other non-covalent interactions) and supramolecular structures in the mechanisms of catalysis. The data obtained from AFM based on nickel and iron complexes, which are effective catalysts and models of active sites of enzymes, indicate a high probability of the formation of supramolecular structures in real conditions of catalytic oxidation, and can bring us closer to understanding enzymes activity. With a sensitive AFM method, it is possible to observe the self-organization of model systems into stable nanostructures due to H-bonds and possibly other non-covalent interactions, which can be considered as a step towards modeling the active sites of enzymes. Methodical approaches of atomic force microscopy for the study of morphological changes of cells have been developed.
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Fan, Shuobing, Rufan Wang, Chen Li, Linquan Bai, Yi-Lei Zhao und Ting Shi. „Insight into Structural Characteristics of Protein-Substrate Interaction in Pimaricin Thioesterase“. International Journal of Molecular Sciences 20, Nr. 4 (18.02.2019): 877. http://dx.doi.org/10.3390/ijms20040877.
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As a polyene antibiotic of great pharmaceutical significance, pimaricin has been extensively studied to enhance its productivity and effectiveness. In our previous studies, pre-reaction state (PRS) has been validated as one of the significant conformational categories before macrocyclization, and is critical to mutual recognition and catalytic preparation in thioesterase (TE)-catalyzed systems. In our study, molecular dynamics (MD) simulations were conducted on pimaricin TE-polyketide complex and PRS, as well as pre-organization state (POS), a molecular conformation possessing a pivotal intra-molecular hydrogen bond, were detected. Conformational transition between POS and PRS was observed in one of the simulations, and POS was calculated to be energetically more stable than PRS by 4.58 kcal/mol. The structural characteristics of PRS and POS-based hydrogen-bonding, and hydrophobic interactions were uncovered, and additional simulations were carried out to rationalize the functions of several key residues (Q29, M210, and R186). Binding energies, obtained from MM/PBSA calculations, were further decomposed to residues, in order to reveal their roles in product release. Our study advanced a comprehensive understanding of pimaricin TE-catalyzed macrocyclization from the perspectives of conformational change, protein-polyketide recognition, and product release, and provided potential residues for rational modification of pimaricin TE.
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Khoder, Hassan, Dominik Schaniel, Sébastien Pillet und El-Eulmi Bendeif. „X-ray scattering study of water confined in bioactive glasses: experimental and simulated pair distribution function“. Acta Crystallographica Section A Foundations and Advances 76, Nr. 5 (20.07.2020): 589–99. http://dx.doi.org/10.1107/s2053273320007834.
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Temperature-dependent total X-ray scattering measurements for water confined in bioactive glass samples with 5.9 nm pore diameter have been performed. Based on these experimental data, simulations were carried out using the Empirical Potential Structure Refinement (EPSR) code, in order to study the structural organization of the confined water in detail. The results indicate a non-homogeneous structure for water inside the pore, with three different structural organizations of water, depending on the distance from the pore surface: (i) a first layer (4 Å) of interfacial pore water that forms a strong chemical bond with the substrate, (ii) intermediate pore water forming a second layer (4–11 Å) on top of the interfacial pore water, (iii) bulk-like pore water in the centre of the pores. Analysis of the simulated site–site partial pair distribution function shows that the water–silica (Ow–Si) pair correlations occur at ∼3.75 Å. The tetrahedral network of bulk water with oxygen–oxygen (Ow–Ow) hydrogen-bonded pair correlations at ∼2.8, ∼4.1 and ∼4.5 Å is strongly distorted for the interfacial pore water while the second neighbour pair correlations are observed at ∼4.0 and ∼4.9 Å. For the interfacial pore water, an additional Ow–Ow pair correlation appears at ∼3.3 Å, which is likely caused by distortions due to the interactions of the water molecules with the silica at the pore surface.
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Roh, Gilltae, Hansung Kim, Hyeonmin Jeon und Kyoungkuk Yoon. „Fuel Consumption and CO2 Emission Reductions of Ships Powered by a Fuel-Cell-Based Hybrid Power Source“. Journal of Marine Science and Engineering 7, Nr. 7 (18.07.2019): 230. http://dx.doi.org/10.3390/jmse7070230.
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The need for technological development to reduce the impact of air pollution caused by ships has been strongly emphasized by many authorities, including the International Maritime Organization (IMO). This has encouraged research to develop an electric propulsion system using hydrogen fuel with the aim of reducing emissions from ships. This paper describes the test bed we constructed to compare our electric propulsion system with existing power sources. Our system uses hybrid power and a diesel engine generator with a combined capacity of 180 kW. To utilize scale-down methodology, the linear interpolation method is applied. The proposed hybrid power source consists of a molten carbonate fuel cell (MCFC), a battery, and a diesel generator, the capacities of which are 100 kW, 30 Kw, and 50 kW, respectively. The experiments we conducted on the test bed were based on the outcome of an analysis of the electrical power consumed in each operating mode considering different types of merchant ships employed in practice. The output, fuel consumption, and CO2 emission reduction rates of the hybrid and conventional power sources were compared based on the load scenarios created for each type of ship. The CO2 emissions of the hybrid system was compared with the case of the diesel generator alone operation for each load scenario, with an average of 70%~74%. This analysis confirmed the effectiveness of using a ship with a fuel-cell-based hybrid power source.
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Davletbaeva, Ilsiya M., Ilnaz I. Zaripov, Alexander I. Mazilnikov, Ruslan S. Davletbaev, Raphael R. Sharifullin, Artem A. Atlaskin, Tatyana S. Sazanova und Ilya V. Vorotyntsev. „Synthesis and Study of Gas Transport Properties of Polymers Based on Macroinitiators and 2,4-Toluene Diisocyanate“. Membranes 9, Nr. 3 (20.03.2019): 42. http://dx.doi.org/10.3390/membranes9030042.
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Nowadays, block copolymers hold great promise for the design of novel membranes to be applied for the membrane gas separation. In this regard, microporous block copolymers based on a macroinitiator with an anionic nature, such as potassium-substituted block copolymers of propylene oxide and ethylene oxide (PPEG) and 2,4-toluene diisocyanate (TDI), were obtained and investigated as effective gas separation membranes. The key element of the macromolecular structure that determines the supramolecular organization of the studied polymers is the coplanar blocks of polyisocyanates with an acetal nature (O-polyisocyanate). In the present research, the influence of the content of peripheral polyoxyethylene (POE) blocks in PPEG on the supramolecular structure processes and gas transport characteristics of the obtained polymers based on PPEG and TDI was investigated. According to the study of polymers if the POE block content is 15 wt %, the polyoxypropylene segments are located in the internal cavity of voids formed by O-polyisocyanate blocks. When the POE block content is 30 wt %, the flexible chain component forms its own microphase outside the segregation zone of the rigid O-polyisocyanate blocks. The permeability for polar molecules, such as ammonia or hydrogen sulfide, significantly exceeds the permeability values obtained for non-polar molecules He, N2 and СН4. A relatively high permeability is also observed for carbon dioxide. At the same time, the content of POE blocks has a small effect on the permeability for all studied gases. The diffusion coefficient increases with an increase in the POE block content in PPEG for all studied gases.
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Gun'ko, V. M. „Quantum-chemically computed integral characteristics of complex nanomaterials“. Himia, Fizika ta Tehnologia Poverhni 12, Nr. 3 (30.09.2021): 157–67. http://dx.doi.org/10.15407/hftp12.03.157.
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Development of theoretical tools to analyze electronic structure of complex nanomaterials depending on features of spatial and chemical organizations of different phases is of interest from both practical and theoretical points of view. Therefore, in this work, an approach based on computations of the atomic charge distribution functions (CDF) in parallel to calculations of the distribution functions of the chemical shifts (SDF) of protons is developed to be applied to a set of complex oxide and carbon nanomaterials. Binary nanooxides (alumina/silica, titania/silica), 3d-metal-doped anatase, activated carbon, carbon nanotube, fullerene C60, graphene oxide, and N-doped Kagome graphene are considered here as representatives of different classes of nanomaterials. The analyses of the CDF and SDF as nonlocal characteristics of certain kinds of atoms in complex systems provide a deeper insight into electronic structure features depending on composition of the materials, guest phase-doped host phase at various amounts of dopants, structure of O- and OH-containing surface sites, amounts and organization of adsorbed water, formation of neutral and charged surface functionalities, bonding of solvated ions, etc. The CDF of metal and hydrogen atoms (electron-donors) are more sensitive to the mentioned factors than the CDF of O, N, and C atoms (electron acceptors) in various systems. As a whole, the use of the CDF and SDF in parallel expands the tool possibility in detailed analysis of the structural and interfacial effects in dried and wetted complex nanomaterials.
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Zhou, Yafei, Junfeng Zhan, Xiang Gao, Cao Li, Konstantin Chingin und Zhanggao Le. „The cation−anion interaction in ionic liquids studied by extractive electrospray ionization mass spectrometry“. Canadian Journal of Chemistry 92, Nr. 7 (Juli 2014): 611–15. http://dx.doi.org/10.1139/cjc-2014-0023.
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Ionic liquids, known as green solvents, are of sustainable interest in modern chemistry, industry, and many other fields. Here, extractive electrospray ionization has been applied to transfer various room temperature ionic liquids into the gas phase for mass spectrometry analysis. Generated mass spectra display free cations (C+), anions (A–), and small salt clusters, such as C2A+ and CA2–, from strongly diluted ionic liquid samples (<10−8 mol/L) with high sensitivity and tolerance to chemical contamination. The eight ionic liquids based on the 1-butyl-3-methylimidazolium cation with different anions (OH–, HSO4–, Cl–, BF4–, AlCl4–, NO3–, Ac–, and PF6–) are investigated in the present work. Interestingly, the 1-butyl-3-methylimidazolium cation signal intensity is inversely correlated with the hydrogen bonding strength between the anion and cation. Our study indicates that the direct extractive electrospray ionization mass spectrometry analysis is a convenient method to screen ionic liquid libraries with regard to chemical composition, physicochemical properties, and supramolecular organization of ionic liquids.
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Xia, Hongjie, Xuping Xie, Jing Zou, Christian G. Noble, William K. Russell, Luis Marcelo F. Holthauzen, Kyung H. Choi, Mark A. White und Pei-Yong Shi. „A cocrystal structure of dengue capsid protein in complex of inhibitor“. Proceedings of the National Academy of Sciences 117, Nr. 30 (15.07.2020): 17992–8001. http://dx.doi.org/10.1073/pnas.2003056117.
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Dengue virus (DENV) was designated as a top 10 public health threat by the World Health Organization in 2019. No clinically approved anti-DENV drug is currently available. Here we report the high-resolution cocrystal structure (1.5 Å) of the DENV-2 capsid protein in complex with an inhibitor that potently suppresses DENV-2 but not other DENV serotypes. The inhibitor induces a “kissing” interaction between two capsid dimers. The inhibitor-bound capsid tetramers are assembled inside virions, resulting in defective uncoating of nucleocapsid when infecting new cells. Resistant DENV-2 emerges through one mutation that abolishes hydrogen bonds in the capsid structure, leading to a loss of compound binding. Structure-based analysis has defined the amino acids responsible for the inhibitor’s inefficacy against other DENV serotypes. The results have uncovered an antiviral mechanism through inhibitor-induced tetramerization of the viral capsid and provided essential structural and functional knowledge for rational design of panserotype DENV capsid inhibitors.
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Нарожный, Анатолий Николаевич. „КВАЗАРИ І РЕГЕНЕРАЦІЯ ВОДНЮ. ЧАСТИНА 2.“ Open Information and Computer Integrated Technologies, Nr. 83 (23.05.2019): 190–201. http://dx.doi.org/10.32620/oikit.2019.83.13.
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Further consequences of the mechanisms of hydrogen regeneration, which are realized in large galaxies during the period of activity of their nuclei, are considered. In addition to the indirect evidence presented in the first part and related to the work of the structures forming the jets, this part of the article considers direct evidence of the existence of these processes in galaxies. The evidence given is based on emissions of regenerated hydrogen into galactic and intergalactic space, as shown by astronomical observations of the Galaxy and its closest surroundings. Evidence is also found among the general observational data of intergalactic astronomy, the origin of which is well explained in the framework of the approach presented. However, these data are traditionally viewed through the prism of the dominant concept, that is, they are interpreted as residual hydrogen, which appeared from the Big Bang. Among the results of galactic astronomy there are data showing the possible contribution of the processes under consideration to the formation of the observable structure of the Milky Way, as well as their involvement in the organization of its satellite galaxies. The criterion is given, according to which galactic gas clouds and star groups can be distinguished, organized from the galaxy's own matter during the period of activity of its nucleus. Using the example of a spiral galaxy, it is suggested that the active galactic nuclei might be involved in the formation of the morphology of the galaxy. It is concluded that the central supermassive object in the period of its activity, performs its main galactic function - carries out the processing of waste of stars in the galaxy. This inverse process closes the chain of the continuous life cycle of the galaxy, which consists of two interrelated processes. The first process is the continuous burning of hydrogen in the stars, and the second is the episodic activity of the galactic nucleus, as a result of which hydrogen is recovered from the "waste", necessary to support direct stellar processes. One more process joins these two processes - the process of returning the energy expended by baryonic matter to electromagnetic radiation. It is realized through the dark component of matter. The main conclusion is made - the Universe as a system is well organized and self-sufficient for its eternal existence, and it does not need any external motivation.
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Beglov, Konstantin V., Alexander I. Brunetkin, Maxim M. Maximov und Elena O. Ulitskaya. „MODEL AND METHOD OF CONTROLLED PYROLYSIS OF ORGANIC SUBSTANCES OF VARIABLE COMPOSITION“. Journal of Automation and Information sciences 1 (01.01.2021): 134. http://dx.doi.org/10.34229/0572-2691-2021-1-12.
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The issues of organization of the process of slow pyrolysis of organic substances, in the general case of unknown and variable composition, are considered. The relevance of the work is determined by considering the possibility of using various organic waste (domestic, agricultural, industrial) without their preliminary sorting and drying to obtain secondary energy resources of a known (controlled) composition. The novelty of the work is due to the development of a model for the method of controlled pyrolysis or gasification of organic substances with a minimum amount of solid residues at a maximum calorific value of the resulting mixture of combustible gases. A process based on filtration combustion in superadiabatic mode is considered. In existing devices, when this mode is implemented, a counter flow of the feedstock and reaction products is organized. As a result, a part of the water vapor generated at the drying stage is part of the mixture of reaction products and, accordingly, reduce their energy value. The scheme of the process proposed for consideration is based on the organization of the associated flow of feedstock and reaction products. As a result, the resulting carbon dioxide and water vapor are used as additional oxidizing agents. As a result, the carbonaceous residue decreases with a simultaneous increase in the composition of the mixture of gaseous products of carbon monoxide and hydrogen. A scheme for real-time monitoring of the composition of the feedstock during pyrolysis (gasification) is proposed. Knowledge of the composition makes it possible to control the process of its processing in order to: a) organize the optimal gasification process in terms of maximizing the amount and energy value of the mixture of gaseous reaction products; b) control the consumption of the processed feedstock in order to produce the required amount of product gas at any given time.
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Diallo, Waly, Libasse Diop, Cheikh Abdoul Khadir Diop, Hélène Cattey und Laurent Plasseraud. „Synthesis, spectroscopic study, and crystal structure of a new organotin(IV) selenate derivative“. Main Group Metal Chemistry 41, Nr. 5-6 (27.11.2018): 183–88. http://dx.doi.org/10.1515/mgmc-2018-0029.
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Abstract The polymeric organotin(IV) selenate complex [(Me3Sn)3(SeO4)(OH)]n (1) has been isolated as single crystals from the reaction of [(Me2NH2)2SeO4] and Me3SnCl in methanol. In the solid state, compound 1 was characterized by X-ray diffraction analysis, Fourier transform-infrared spectroscopy, and elemental analysis. 1 crystallizes in the orthorhombic system space group Pbca with a=11.0231(2) Å, b=16.3461(3) Å, c=20.9945(4) Å, α=β=γ=90°, V=3782.89(12) Å3, and Z=8. Its structure can be described as a polymeric zigzag chain based on Me3Sn moieties linked by tridentate selenate anions. Pendant (Me3Sn)2OH groups are also connected to the chain, according to a syndiotactic organization, and via Sn-O-Se bonds. Intermolecular OH···O hydrogen bonds and long Se-O···Sn distance interactions promote the association of chains together and lead to the propagation of a three-dimensional network. In addition, the behavior of 1 in solution (methanol) was also studied by multinuclear nuclear magnetic resonance spectroscopy and mass spectrometry.
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Reusser, Carlos A., und Joel R. Pérez Osses. „Challenges for Zero-Emissions Ship“. Journal of Marine Science and Engineering 9, Nr. 10 (22.09.2021): 1042. http://dx.doi.org/10.3390/jmse9101042.
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Due to the increasing impact of ship emissions on the environment and the preventive measures of current regulations introduced by the International Maritime Organization to significantly reduce them, the development of ocean-going all-electric ships has been addressed as a concept applied to achieve it. Being a promising technology considers the use of technology alternatives such as fuel cells, batteries, and supercapacitors together with the use of zero-carbon alternative fuels such as hydrogen (H2) and ammonia (NH3) as main energy sources. This article addresses a state-of-the-art on several challenges related to the ocean-going zero-emissions ship to achieve a zero-emissions shipping, based on the technology associated with hybrid and all-electric ship, and the zero-carbon fuels alternatives. In this respect, a transition from fossil fuel-based propulsion and auxiliary systems to a zero-emissions ship concept are related to the challenges to overcome the needs of energy density for these new alternatives energy sources compared to current fossil fuel options. The transitional process should consider a first step of hybridization of the propulsion and auxiliary systems of existing ships to get a baseline from where to move forward to a zero-emissions configuration for new designs.
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Адамян, Анна Нориковна, Александра Ивановна Иванова, Елена Михайловна Семенова, Максим Дмитриевич Малышев, Светлана Дмитриевна Хижняк und Павел Михайлович Пахомов. „INFLUENCE OF LIGHTING ON THE SELF-ORGANIZATION PROCESS IN CYSTEINE-SILVER SOLUTION“. Вестник Тверского государственного университета. Серия: Химия, Nr. 1(43) (13.04.2021): 60–68. http://dx.doi.org/10.26456/vtchem2021.1.8.
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Комплексно исследовано влияние дневного освещения на процесс самоорганизации в цистеин-серебряном растворе (ЦСР) и гидрогелях на его основе. Установлено, что ЦСР на основе L-цистеина и ацетата серебра под действием освещения окрашивается сначала в желтый, а затем в коричневый цвет, что является следствием плазмонного резонанса на образующихся наночастицах серебра (НЧС) в ЦСР и гидрогелях. Предложена модель формирования НЧ в гидрогеле. The effect of daylight on the self-assembly process in cysteine-silver solution (CSS) and hydrogels based on it has been comprehensively studied. It was found that CSS based on L-cysteine and silver acetate under the action of illumination first turns yellow and then brown, which is a consequence of plasmon resonance on the resulting silver nanoparticles in CSS and hydrogels. A model for the formation of silver nanoparticles in a hydrogel is proposed.
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Przybyła, Mateusz, und Andrzej Adamkiewicz. „Quantity and Quality of Dual Fuel IC Marine Engine Exhaust Sensible Waste Heat Considering Different Sulphur Content in Fuels“. E3S Web of Conferences 137 (2019): 01045. http://dx.doi.org/10.1051/e3sconf/201913701045.
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Maritime transport is facing a significant set of technical challenges due to planned by the International Maritime Organization implementation of ecological criterions on 01 January 2020 and 2021 regarding the emission of sulphur oxides, carbon dioxide and nitrogen oxides. The advantageous properties of natural gas (NG) as fuel in conjunction with dual fuel (DF) internal combustion (IC) engines potentially enables the fulfilment of all planned criterions. However, if the methane emission of DF IC is taken into consideration in CO2 emission balance it completely devaluates the advantages arising from high hydrogen to carbon ratio of NG. On the other hand, the planned global sulphur cap in combination with its low content in NG potentially enables to recover higher rates of waste heat and exergy of combustion products without the risk of low temperature corrosion (compared to liquid fuel). In this study the influence of sulphur content in NG and pilot fuel on the sulphuric acid condensation temperature was investigated in order to determine the rate of waste heat (quantity) and exergy (quality) of four stroke DF IC engine combustion products. In ideal process scenario (exergy based) the methane slip effect compensation was achieved only for a 0,5 engine load.
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Afanasyev, A. V., A. A. Mel’nikov, S. V. Konovalov und M. I. Vaskov. „The Analysis of the Influence of Various Factors on the Development of Stress Corrosion Defects in the Main Gas Pipeline Walls in the Conditions of the European Part of the Russian Federation“. International Journal of Corrosion 2018 (03.06.2018): 1–10. http://dx.doi.org/10.1155/2018/1258379.
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This paper considers the factors influencing the formation and development of stress corrosion defects detected during the inspection and overhaul of the main gas pipeline section. The surveyed gas pipeline is made of large diameter steel pipes made by controlled rolling, produced by various companies, with the predominance of pipes produced by the Khartsyzsk Pipe Plant (KhPP). The correlation between the geometric parameters of defects is described, which makes it possible to estimate the depth of cracks by external parameters. Mechanical tests by cyclic loading of samples containing cracks, based on the site operation data for the last 11 years, showed no crack growth in the absence of a corrosive medium. Micro-X-ray spectral analysis of metal and corrosion products showed no trace of the influence of hydrogen sulphide and nonmetallic inclusions (sulphides) on the development process of SCC. According to the results of the research, the process of development of stress corrosion on the main gas pipelines located in the European part of the Russian Federation is described. The organization operating the gas pipeline is recommended to take into consideration the results of this work during drawing up their repair plan.
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Адамян, Анна Нориковна, Алена Константиновна Кучурова, Александра Ивановна Иванова, Максим Дмитриевич Малышев, Виктор Анатольевич Герасин, Вячеслав Михайлович Червинец, Светлана Дмитриевна Хижняк und Павел Михайлович Пахомов. „INFLUENCE OF POLIGUANIDINE ON THE SELF-ORGANIZATION PROCESS IN CYSTEINE-SILVER SOLUTION“. Вестник Тверского государственного университета. Серия: Химия, Nr. 1(43) (13.04.2021): 69–79. http://dx.doi.org/10.26456/vtchem2021.1.9.
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Выполнены реологические, структурные и антибактериальные исследования гидрогелей, получаемых на основе L-цистеина, ацетата серебра и полигексаметиленгуанидин гидрохлорида (ПГМГ-ГХ). Установлено, что водные растворы на основе L-цистеина и ацетата серебра хорошо смешиваются с водным раствором ПГМГ-ГХ, образуя прозрачные гидрогели. Предложена модель строения пространственной сетки геля. Показана высокая антимикробная активность гидрогеля по отношению к тест-культурам патогенных и условно-патогенных микроорганизмов. Rheological, structural, and antibacterial studies of hydrogels based on L-cysteine, silver acetate, and polyhexamethylene guanidine hydrochloride (PHMG-GC) have been carried out. It was found that aqueous solutions based on L-cysteine and silver acetate mix well with an aqueous solution of PHMG-GC, forming transparent hydrogels. A model of the structure of the spatial grid of the gel is proposed. High antimicrobial activity of the hydrogel was shown in relation to test cultures of pathogenic and opportunistic microorganisms.
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Jung, Eun-Young, Byungryul An und Heejong Son. „Effect of Phosphate and Hydrogen Peroxide on Bacterial Community and Removal Efficiency of Biological Activated Carbon (BAC) Process for Enhanced Biofiltration“. Journal of Korean Society of Environmental Engineers 43, Nr. 1 (31.01.2021): 20–31. http://dx.doi.org/10.4491/ksee.2021.43.1.20.
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Objectives:The correlation between the organic material removal ability of the enhanced BAC process injected by the phosphate (PO4-P) and/or hydrogen peroxide (H2O2) and attached bacterial community was evaluated.Methods:As pilot plant for the purification of raw water downstream of Nakdong river, 4 acrylic columns with an inner diameter of 20 cm and a height of 250 cm were operated at an empty bed contact time of 20 minutes. The four BAC columns are as followed; conventional BAC (control-BAC), enhanced BAC with phosphorus (PO4-P+BAC), enhanced BAC with hydrogen peroxide (H2O2+BAC), and enhanced BAC with phosphorus and hydrogen peroxide (PO4-P+H2O2+BAC). 0.01 mg/L of PO4-P and 1 mg/L of H2O2 were added in influent in the enhanced BAC, respectively. After 18 months of operation, activated carbon was collected from the top of each BAC column and 16S rRNA amplicon sequence analysis was performed.Results and Discussion:The long-term addition of PO4-P and H2O2 contributes the increase of biomass and activity of attached bacteria, respectively. In the attached bacterial community of conventional and enhanced process, Proteobacteria phylum is the most dominant specie and both α-Proteobacteria class and β-Proteobacteria class are also highly present. Each enhanced BAC exhibits very high bacterial community similarity based on the composition of various genera but it is completely different with conventional BAC. In particular, Bradyrhizobium, Sphingomonas, Methylobacterium, Sphingobium, Belnapia, Burkholderia, Polaromonas, and Desulfuromonas, which have excellent metabolism functions for a wide range of organic substrates, are highly dominated in the enhanced BAC process. The concentration of Biodegradable Dissolved Organic Carbon (BDOC) is obtained close to 0.15 mg/L for conventional BAC and less than 0.15 mg/L for enhanced BAC process, respectively. In general, the higher BDOC concentration can result in reducing biostability in water supply and distribution system when the residual chlorine concentration does not meet requirements. As result, less than 0.15 mg/L BDOC accomplished by PO4-P and H2O2 enhances the biostability.Conclusions:Compared to the conventional BAC process, the biomass and activity of attached bacteria and the ratio of the organization composition of the bacteria insides (genus) are considerably higher in the enhanced BAC process. These results achieve higher water quality and improve biostability.
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Zhang, Ning, Vincent Milleret, Greta Thompson-Steckel, Ning-Ping Huang, János Vörös, Benjamin R. Simona und Martin Ehrbar. „Soft Hydrogels Featuring In-Depth Surface Density Gradients for the Simple Establishment of 3D Tissue Models for Screening Applications“. SLAS DISCOVERY: Advancing the Science of Drug Discovery 22, Nr. 5 (09.03.2017): 635–44. http://dx.doi.org/10.1177/2472555217693191.
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Three-dimensional (3D) cell culture models are gaining increasing interest for use in drug development pipelines due to their closer resemblance to human tissues. Hydrogels are the first-choice class of materials to recreate in vitro the 3D extra-cellular matrix (ECM) environment, important in studying cell-ECM interactions and 3D cellular organization and leading to physiologically relevant in vitro tissue models. Here we propose a novel hydrogel platform consisting of a 96-well plate containing pre-cast synthetic PEG-based hydrogels for the simple establishment of 3D (co-)culture systems without the need for the standard encapsulation method. The in-depth density gradient at the surface of the hydrogel promotes the infiltration of cells deposited on top of it. The ability to decouple hydrogel production and cell seeding is intended to simplify the use of hydrogel-based platforms and thus increase their accessibility. Using this platform, we established 3D cultures relevant for studying stem cell differentiation, angiogenesis, and neural and cancer models.
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d’Ambrosio, Stefano, Ezio Spessa und Alberto Vassallo. „Methods for Specific Emission Evaluation in Spark Ignition Engines Based on Calculation Procedures of Air-Fuel Ratio: Development, Assessment, and Critical Comparison“. Journal of Engineering for Gas Turbines and Power 127, Nr. 4 (20.09.2005): 869–82. http://dx.doi.org/10.1115/1.1852566.
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New computational procedures are proposed for evaluating the exhaust brake specific mass emissions of each pollutant species in internal combustion (IC) engines. The procedures start from the chemical reaction of fuel with combustion air and, based on the measured exhaust raw emissions THC, CH4,NOx, CO, O2,CO2, calculate the volume fractions of the compounds in the exhaust gases, including those that are not usually measured, such as water, nitrogen and hydrogen. The molecular mass of the exhaust gases is then evaluated and the brake specific emissions can be obtained if the exhaust flow rate and the engine power output are measured. The algorithm can also be applied to the evaluation of air-fuel ratio from measured raw volume emissions of IC engines. The new procedures take the effects of various fuel and combustion air compositions into account, with particular reference to different natural gas blends as well as to the presence of water vapor, CO2, Ar and He in the combustion air. In the paper, the algorithms are applied to the evaluation of air-fuel ratio and brake specific mass emissions in an automotive bi-fuel Spark Ignition (SI) engine with multipoint sequential port-fuel injection. The experimental tests were carried out in a wide range of steady-state operating conditions under both gasoline and compressed natural gas operations. The specific emissions calculated from the new procedures are compared to those evaluated by applying Society of Automotive Engineers (SAE) and International Standards Organization (ISO) recommended practices and the air-fuel ratio results are compared to those obtained either from directly measured air and fuel mass flow rates or from Universal Exhaust Gas Oxygen (UEGO) sensor data. The sensitivity of the procedure results to the main engine working parameters, the influence of environmental conditions (in particular the effect of air humidity on NOx formation) and the experimental uncertainties are also determined.
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Rádai, Zita, Nóra Zsuzsa Kiss, Mátyás Czugler, Konstantin Karaghiosoff und György Keglevich. „The typical crystal structures of a few representative α-aryl-α-hydroxyphosphonates“. Acta Crystallographica Section C Structural Chemistry 75, Nr. 3 (12.02.2019): 283–93. http://dx.doi.org/10.1107/s2053229619001839.
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The crystal structures of seven α-aryl-α-hydroxyphosphonates synthesized by the Pudovik reaction of substituted benzaldehydes and dialkyl phosphites, namely dimethyl [(hydroxy)(phenyl)methyl]phosphonate, C9H13O4P, dimethyl [(3,4-dimethoxyphenyl)(hydroxy)methyl]phosphonate, C11H17O6P, dimethyl (1-hydroxy-1-phenylethyl)phosphonate, C10H15O4P, dimethyl [1-hydroxy-1-(4-nitrophenyl)ethyl]phosphonate, C10H14NO6P, dibenzyl [hydroxy(2-nitrophenyl)methyl]phosphonate, C21H20NO6P, dibenzyl [(3-chlorophenyl)(hydroxy)methyl]phosphonate, C21H20ClO4P, and dibenzyl [hydroxy(4-methylphenyl)methyl]phosphonate, C22H23O4P, were studied to gain a better understanding of the organization in this type of molecule in the solid state. The crystals obtained for this series of compounds show a balance between C—OH...O=P chain-linked packing and the dimeric types of hydrogen-bond bridges of intermolecular pairs of such functions. The description is based on primary graph-set descriptors. Using graph-set descriptors one level deeper (i.e. secondary graph sets of the C—H...O type) revealed a similarity in the graph-set descriptors, suggesting a fine interplay of substituent- and shape-dependent effects on strong–weak interactions. It seems that the formation of chains or dimers is governed not only by the presence of a tertiary Cα atom, but also by the nature and crowding of the ortho substituents of the α-aryl group.
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Gao, Linda, Frans A. van Nieuwpoort, Jacoba J. Out-Luiting, Paul J. Hensbergen, Femke A. de Snoo, Wilma Bergman, Remco van Doorn und Nelleke A. Gruis. „Genome-Wide Analysis of Gene and Protein Expression of Dysplastic Naevus Cells“. Journal of Skin Cancer 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/981308.
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Cutaneous melanoma, a type of skin tumor originating from melanocytes, often develops from premalignant naevoid lesions via a gradual transformation process driven by an accumulation of (epi)genetic lesions. These dysplastic naevi display altered morphology and often proliferation of melanocytes. Additionally, melanocytes in dysplastic naevi show structural mitochondrial and melanosomal alterations and have elevated reactive oxygen species (ROS) levels. For this study we performed genome-wide expression and proteomic analysis of melanocytes from dysplastic naevus (DNMC) and adjacent normal skin (MC) from 18 patients. Whole genome expression profiles of the DNMC and MC of each individual patient subjected to GO-based comparative statistical analysis yielded significantly differentially expressed GO classes including “organellar ribosome,” “mitochondrial ribosome,” “hydrogen ion transporter activity,” and “prefoldin complex.” Validation of 5 genes from these top GO classes revealed a heterogeneous differential expression pattern. Proteomic analysis demonstrated differentially expressed proteins in DNMC that are involved in cellular metabolism, detoxification, and cytoskeletal organization processes, such as GTP-binding Rho-like protein CDC42, glutathione-S-transferase omega-1 and prolyl 4-hydroxylase. Collectively these results point to deregulation of cellular processes, such as metabolism and protein synthesis, consistent with the observed elevated oxidative stress levels in DNMC potentially resulting in oxidative DNA damage in these cells.
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Vo, Trung Nghia, Julia Malo Pueyo, Khadija Wahni, Daria Ezeriņa, Jesalyn Bolduc und Joris Messens. „Prdx1 Interacts with ASK1 upon Exposure to H2O2 and Independently of a Scaffolding Protein“. Antioxidants 10, Nr. 7 (30.06.2021): 1060. http://dx.doi.org/10.3390/antiox10071060.
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Hydrogen peroxide (H2O2) is a key redox signaling molecule that selectively oxidizes cysteines on proteins. It can accomplish this even in the presence of highly efficient and abundant H2O2 scavengers, peroxiredoxins (Prdxs), as it is the Prdxs themselves that transfer oxidative equivalents to specific protein thiols on target proteins via their redox-relay functionality. The first evidence of a mammalian cytosolic Prdx-mediated redox-relay—Prdx1 with the kinase ASK1—was presented a decade ago based on the outcome of a co-immunoprecipitation experiment. A second such redox-relay—Prdx2:STAT3—soon followed, for which further studies provided insights into its specificity, organization, and mechanism. The Prdx1:ASK1 redox-relay, however, has never undergone such a characterization. Here, we combine cellular and in vitro protein–protein interaction methods to investigate the Prdx1:ASK1 interaction more thoroughly. We show that, contrary to the Prdx2:STAT3 redox-relay, Prdx1 interacts with ASK1 at elevated H2O2 concentrations, and that this interaction can happen independently of a scaffolding protein. We also provide evidence of a Prdx2:ASK1 interaction, and demonstrate that it requires a facilitator that, however, is not annexin A2. Our results reveal that cytosolic Prdx redox-relays can be organized in different ways and yet again highlight the differentiated roles of Prdx1 and Prdx2.
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Yano, Yuki, Kazuya Wada, Takuya Aoki, Toshio Ogasawara und Shinjiro Umezu. „Fabrication and Mechanical Properties of C/C-HfC-SiC Composites“. Key Engineering Materials 625 (August 2014): 657–61. http://dx.doi.org/10.4028/www.scientific.net/kem.625.657.
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Reusable spacecraft/supersonic aircraft is research and development towards the realization of a new aerospace transportation system.Because these transport aircraft is to flight at a speed of more than Mach 5,are considering the use of scramjet engine.Because this engine uses air as an oxidant and liquid hydrogen as a fuel,the combustion gas temperature is more than 2500°C.So the combustor is required lightweight material and super-heat-resistant material.In the field of aerospace,SiC-based ceramics that is heat-resistant materials are well known as to maintain the mechanical properties at high temperatures and have a high oxidation resistance.However, this material limit as heat-resistant material is about 1600 °C .Therefore, it can not be used in an environment of scramjet engine combustor.There are the measures by metal structure to be force-cooled by refrigerant fuel,but apply is difficult because the system is complexity and very heavy. In this study use the hafnium-based super heat-resistant ceramics that is having a melting point more than 2000°C. Purpose is to develop a new technique for forming the ceramics mainly composed from Hafnium Carbide (Melting point:3950°C) that is very high melting point and have oxidation resistance by melt impregnation to inside C/C composite.In addition, implement the evaluation of changes in the organization after each process by the cross-sectional observation and strength assessment by three-point bending test.
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ВABOV, Konstantin, Sergеy GUSHCHA, Khrystyna KOIEVA, STRUS Oksana, Boris NASIBULIN, Galina DMITRIEVA, Mikhailo АRABADJI und Alexander PLAKIDA. „Comparative assessment of biological activity of peloids of Ukraine of different genesis“. Balneo Research Journal, Vol.11, no.4 (05.12.2020): 467–71. http://dx.doi.org/10.12680/balneo.2020.380.
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The article presents the results of comprehensive studies of the influence of peloids from different geographic regions of Ukraine and different genesis on the course of experimental pathology. Methods:At the first stage of research we have determined the type of peloids these are medium-mineralized weakly sulfide magnesium-sodium silt peloids, low-ash organic sapropels, and peat low-mineralized high-ash sulfide-free peloids. Physicochemical parameters have been established: mass fraction of moisture, volumetric weight, hydrogen sulfide content, contamination with particles with a diameter greater than 0.25 × 10-3 m, shear stress, stickiness, specific heat capacity, the content of organic substances, colloidal complex, the concentration of water conduit ions (pH) , redox potential (Eh). In the second stage of the study, 55 white rats were examined for the state of the liverʹs detoxification function (by carrying out a metabolic test using sodium thiopental) and the morphological form of the liver in normal conditions and toxic alcoholic hepatosis. The toxic alcoholic hepatosis model was induced by daily (30 days) intragastric watering of animals with a 25% solution of ethyl alcohol. From the 15th day, the rats received a course of applications: a cake with the corresponding peloids was applied to the bare part of the back. Results: It was determined that the peloids used had a positive effect on animalsʹ condition, which was expressed in the restoration of the detoxification function of the liver and its structural and functional organization. The most substantial positive effect is observed when using silt-sulfide peloids, which, according to the authors, is due to the peculiarities of their physicochemical composition (increased content of magnesium, chlorides, sodium, as well as hydrogen sulfide). Conclusion: Based on the results obtained, it was concluded that the studied peloids meet the criteria for the quality of therapeutic peloids in terms of physicochemical parameters, biological activity, and expands the possibilities of their application in balneology. Keywords: liver, toxic alcoholic hepatosis, rats, peloids,
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Lindstad, Elizabeth, und Agathe Rialland. „LNG and Cruise Ships, an Easy Way to Fulfil Regulations—Versus the Need for Reducing GHG Emissions“. Sustainability 12, Nr. 5 (08.03.2020): 2080. http://dx.doi.org/10.3390/su12052080.
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Liquified natural gas (LNG), with its low sulphur content, its favorable hydrogen-to-carbon ratio, and the lower nitrogen oxide emission when combusted compared to conventional fuels, fulfils all International Maritime Organization (IMO) air emission regulations. For the cruise industry, with their large number of customers and their high public visibility, LNG has therefore become a tempting option for new cruise ships. However, larger well-to-tank (WTT) emissions for the LNG supply chain as well as un-combusted methane (CH4) from the ship’s engine might more than nullify any greenhouse gas (GHG) gains. Previous studies have shown very different GHG impacts from the use of LNG as a ship fuel. With climate change potentially being the largest threat to mankind, it is important that decisions with an impact on future GHG emissions are based on the best available knowledge within a sector and across sectors. The motivation for this study has therefore been to establish comparable GHG estimates for well-to-wake (WTW) emissions for LNG and traditional fuels in a transparent way. The results show that there is a need for adopting policies that can reduce the broader GHG emissions of shipping instead of CO2 only, including the well-to-tank emissions of ship fuels. If not, we might end up with a large number of ships with GHG savings on paper only, while the real GHG emissions increases.
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Shipunov, Boris Pavlovich, und Andrey Valerievich Ryabykh. „EFFECT OF HIGH-FREQUENCY ELECTROMAGNETIC FIELD ON THE MUTAROTATION OF AQUEOUS SOLU-TIONS OF GLUCOSE AND FRUCTOSE“. chemistry of plant raw material, Nr. 3 (15.05.2019): 235–40. http://dx.doi.org/10.14258/jcprm.2019034456.
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The indirect influence of the high-frequency electromagnetic field of the 30–200 MHz low power range on the reaction rate of the mutation of D-glucose solutions and on the equilibrium in D-fructose and D-glucose solutions was studied. Solutions were prepared using both deionized water and water exposed to a high-frequency electromagnetic field. Control of the process of mutarotation was carried out polarimetrically. To assess the effectiveness of field exposure, the effective constants of the reaction rate of mutarotation were calculated. It has been established that the rate of mutarotation of D-glucose solutions non-linearly decreases with increasing frequency of the electromagnetic field. The effect of pretreatment of the solvent by an electromagnetic field on the equilibrium in solutions of fructose and glucose, which have been subjected to field exposure, has been studied. The observation was carried out for 30 days. It was found that the equilibrium specific rotation in the fructose solution as a result of the influence of the electromagnetic field shifts towards negative values, and in the case of glucose solution it does not change. An explanation of the results obtained is proposed, which is based on the assumption of a change in the structural organization of the solvent - water as a result of the high-frequency electromagnetic field, which can significantly change the hydration interactions of the reaction participants: carbohydrates and hydrogen ions.
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Pentzold, Stefan, Mikael Kryger Jensen, Annemarie Matthes, Carl Erik Olsen, Bent Larsen Petersen, Henrik Clausen, Birger Lindberg Møller, Søren Bak und Mika Zagrobelny. „Spatial separation of the cyanogenic β-glucosidase ZfBGD2 and cyanogenic glucosides in the haemolymph of Zygaena larvae facilitates cyanide release“. Royal Society Open Science 4, Nr. 6 (Juni 2017): 170262. http://dx.doi.org/10.1098/rsos.170262.
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Low molecular weight compounds are typically used by insects and plants for defence against predators. They are often stored as inactive β-glucosides and kept separate from activating β-glucosidases. When the two components are mixed, the β-glucosides are hydrolysed releasing toxic aglucones. Cyanogenic plants contain cyanogenic glucosides and release hydrogen cyanide due to such a well-characterized two-component system. Some arthropods are also cyanogenic, but comparatively little is known about their system. Here, we identify a specific β-glucosidase ( ZfBGD2) involved in cyanogenesis from larvae of Zygaena filipendulae (Lepidoptera, Zygaenidae), and analyse the spatial organization of cyanide release in this specialized insect. High levels of ZfBGD2 mRNA and protein were found in haemocytes by transcriptomic and proteomic profiling. Heterologous expression in insect cells showed that ZfBGD2 hydrolyses linamarin and lotaustralin, the two cyanogenic glucosides present in Z. filipendulae . Linamarin and lotaustralin as well as cyanide release were found exclusively in the haemoplasma. Phylogenetic analyses revealed that ZfBGD2 clusters with other insect β-glucosidases, and correspondingly, the ability to hydrolyse cyanogenic glucosides catalysed by a specific β-glucosidase evolved convergently in insects and plants. The spatial separation of the β-glucosidase ZfBGD2 and its cyanogenic substrates within the haemolymph provides the basis for cyanide release in Z. filipendulae . This spatial separation is similar to the compartmentalization of the two components found in cyanogenic plant species, and illustrates one similarity in cyanide-based defence in these two kingdoms of life.
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Desideri, A., und M. Falconi. „Prokaryotic Cu,Zn superoxide dismutases“. Biochemical Society Transactions 31, Nr. 6 (01.12.2003): 1322–25. http://dx.doi.org/10.1042/bst0311322.
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The Cu,ZnSODs (Cu,Zn superoxide dismutases) comprise a class of ubiquitous metalloenzymes that catalyse the dismutation of the superoxide radical anion into oxygen and hydrogen peroxide. The dismutation reaction involves two successive encounters of the superoxide anion with a catalytic copper centre hosted by the enzyme at the dead end of a narrow protein channel. Cu,ZnSOD is found in all eukaryotic species as a homodimeric enzyme of approx. 2×16 kDa. Cu,ZnSODs are also widely distributed in the prokaryotic phyla, and are found in the periplasmic space of bacterial pathogens, where they are likely to play a defensive role against extracellular oxidative stress, particularly with respect to phagocytic processes. The crystallographic structures of prokaryotic Cu,ZnSODs have shown that the core structural organization of the enzyme is based on a flattened antiparallel β-barrel, composed of eight strands arranged in a Greek-key topological order, which usually forms a dimeric structure through the interaction of residues provided by β-strands 4f and 5e with the 2,3 and 7,8 loops. The interface residues are arranged to form a closed ring, which surrounds a central cavity filled by water molecules that are arranged differently depending on the species. The interface variability of residues and solvent structure observed in bacterial enzymes permits fine tuning of the subunit association that results in the presence of monomeric and dimeric species, and confers a particular protein flexibility that gives rise to long-range communications between different region of the enzyme.