Simultaneous Transformations Research Articles

Chemo-, regio- and stereoselective access to polysubstituted 1,3-dienes via Nickel-catalyzed four-component reactions

1,2-Difunctionalization of alkynes offers a straightforward approach to access polysubstituted alkenes. However, simultaneous multi-component cascade transformations including difunctionalization of two alkynes with both syn- and anti-selectivity in one catalyst system is undeveloped and proves to be a significant challenge. Herein, we report a Nickel-catalyzed four-component reaction to access polysubstituted 1,3-dienes using two terminal alkynes, aryl boroxines, and perfluoroalkyl iodides, wherein the reaction forms three new C-C bonds in a single vessel and serve as a modular strategy to access polysubstituted 1,3-dienes with excellent chemoselectivity, good regioselectivity and exclusive stereoselectivity. Control experiments reveal the plausible reaction mechanism and DFT calculations explain the cause for the formation of this unusual four-component reaction. Furthermore, we successfully incorporate two biologically active units into 1,2,3,4-tetrasubstituted 1,3-dienes, which greatly increases the diversity of molecular scaffolds and brings more potential values to medicinal chemistry, the synthetic utility of our protocol is further demonstrated by the late-stage transformations.

Synergistic effect on simultaneous treatment of Cr(VI) and chloramphenicol using a non-thermal plasma technology

Toxic organic and heavy metal contaminants commonly exist in industrial waste stream(s) and treatment is of great challenge. In this study, a dielectric barrier discharge (DBD) non-thermal plasma technology was employed for the simultaneous treatment of two important contaminants, chloramphenicol (CAP) and Cr(VI) in an aqueous solution through redox transformations. More than 70% of CAP and 20% of TOC were degraded in 60 min, while Cr(VI) was completely removed in 10 min. The hydroxyl radicals were the main active species for the degradation. Meanwhile, the consumption of hydroxyl radicals was beneficial to the reduction of Cr(VI). The synergistic effect was investigated between CAP degradation and Cr(VI) reduction. The reduction of Cr(VI) would be enhanced in the presence of CAP with a low concentration and could be inhibited under a high concentration, because part of hydroxyl radicals could be consumed by the low-concentration CAP and the obtained intermediates with a higher kinetic rate. However, CAP with a high concentration could react with such reductive species as eaq− and •H, which could compete with Cr(VI) and inhibit the reduction. In addition, the presence of Cr(VI) enhanced the degradation and mineralization of CAP; the study of obtained intermediates indicated that the presence of Cr(VI) changed the degradation path of CAP as Cr(VI) would react with reductive species, enhance the generation of hydroxyl radicals, and cause more hydroxylation reactions. Moreover, the mechanism for the simultaneous redox transformations of CAP and Cr(VI) was illustrated. This study indicates that the DBD non-thermal plasma technology can be one of better solutions for simultaneous elimination of heavy metal and organic contaminants in aquatic environments.

Non-targeted facilitation of primary sludge anaerobic fermentation by micro-aeration and the simultaneous nutrients transformations

Anaerobic fermentation is a widely used technology for resource recovery from municipal sludge (e.g., primary sludge). Micro-aeration is an emerging strategy which can be incorporated into this technology. However, the effect of micro-aeration on the anaerobic fermentation performance and the nutrients transformations are not well known. This study investigated the impact of micro-aeration on the production of volatile fatty acids (VFAs) from primary sludge as well as the simultaneous nitrogen (N) and phosphorus (P) transformations in the system. The obtained results indicated that application of micro-aeration improved the microbial activities and facilitated all the hydrolysis, acetogenesis and methanogenesis processes. Hydrogenotrophic methanogen was enriched by micro-aeration while the acetoclastic methanogenesis was still the dominant CH4 production pathway at gene level. The concentration of VFAs was lower with micro-aeration than in the control system, which could be attributed to the enhanced consumption of VFAs. The simultaneous transformations of N and P were observed with different patterns. Micro-aeration led to removal of up to 131.6 mg/L of N, with occurrence of nitrification and denitrification found to be responsible for the N removal. In contrast, the total P content remained unchanged in the reactor. However, micro-aeration was found to inhibit both extracellular organic-P mineralization and intracellular poly-P degradation, resulting in lower soluble PO43−-P and more P distributed in the organic-P fraction in solid phase. This study provides novel insights into the microscopic mechanisms of the micro-aeration on anaerobic fermentation and the simultaneous regulation of N and P release.

Anammox-Mediated Hydroxyapatite Granules: Physicochemical Properties, 3D Hierarchy, and Biofilm Thickness.

Biomineralization inspired the development of simultaneous biological transformations and chemical precipitation for simultaneous nitrogen removal and phosphorus recovery from wastewater, which could compensate for the incapacity of phosphorus management in the new biological route of anaerobic ammonium oxidation (anammox). In this study, we strengthened anammox-mediated biomineralization by long-term feeding of concentrated N, P, and Ca substrates, and a self-assembled matrix of anammox bacteria and hydroxyapatite (HAP) was fabricated in a granular shape, defined as HAP-anammox granules. HAP was identified as the dominant mineral using elemental analysis, X-ray diffraction, and Raman spectroscopy. The intensive precipitation of HAP resulted in a higher inorganic fraction and substantially improved settleability of anammox biomass, which facilitated HAP precipitation by acting as nucleation and metabolically elevated pH. By using X-ray microcomputed tomography, we visually represented the hybrid texture of interwoven HAP pellets and biomass, the core-shell layered architecture of different-sized HAP-anammox granules, and their homogeneously regulated thickness of the outer biofilm (from 118 to 635 μm). This unique architecture endows HAP-anammox granules with outstanding settleability, active biofilm, and tightly bonded biofilm with the carrier, which may explain the excellent performance of these HAP-anammox granules under various challenging operational conditions in previous studies.

The perception of job insecurity and organizational citizenship behavior during COVID-19: the moderating roles of positive psychological capital and grit

PurposeIn light of COVID-19 and its subsequent disruptions, along with simultaneous changes and transformations taking place, job insecurity (JI) is significantly heightened among employees. This study aims to analyze how JI influences employees’ organizational citizenship behaviors (OCBs) and whether positive psychological capital (PsyCap) and grit moderate this relationship.Design/methodology/approachTo test the study hypotheses, data was gathered during COVID-19 via convenience sampling. The collected data was analyzed using the Statistical Package for the Social Sciences software and Excel MegaStat.FindingsThe empirical data shows that qualitative JI has a negative relationship with OCB. PsyCap and grit moderate the relationship between both JI dimensions and OCB.Practical implicationsManagers can alleviate JI in the workplace by promoting PsyCap and grit among employees, both of which will sustain and promote OCB, even during difficult times.Originality/valueThis study bridges the gap in the literature regarding the impact of JI on employees’ OCB during the pandemic. This study also adds to the limited number of studies exploring personal resources as potential moderators between JI and organization citizenship behavior.

Transformations in Sexual Consent

How is the #MeToo movement reshaping everyday life? In this article and our forthcoming book (Gender Revolution: How Electoral Politics and #MeToo are Reshaping Everyday Life, Routledge), we examine the simultaneous profound transformations, and potent challenges to these changes, that we are witnessing in both the public and private arenas. This gender revolution has led to a culture in which people of all genders increasingly reject abuses of power in interpersonal relationships. Transformations in discourses surrounding sexual consent, harassment and assault, although also vigorously contested, are creating gendered social and cultural change at both the political and personal levels.

Cohort fertility heterogeneity during the fertility decline period in Turkey.

The decline in fertility, rapid urbanization and the increase in women's education levels in Turkey are simultaneous transformations. The coexistence and interaction of these transformations is the focal point for the interpretation of fertility trajectories in Turkey. This article explores Turkey's heterogeneous fertility structure by examining the fertility trajectories of women between 1949 and 1978 cohorts. It also examines changes in these trajectories in light of Turkey's fertility decline and interprets those changes through comparisons of women whose fertility behaviors are similar. Using three waves (1998, 2008 and 2018) of the Turkey Demographic and Health Survey data, we employed sequence analysis to calculate fertility trajectories and form clusters from these trajectories. The background similarities of women in the same fertility clusters were investigated with distance analysis, and we calculated predicted probabilities from multinomial logistic regression results and predicted cluster membership. The heterogeneous nature of fertility in Turkey during the demographic transition period shaped the transition process and it can be predicted that such heterogeneity will shape post-transition fertility. The behavior of having two children became the norm during this period, and greater spacing between births or even stopping after the first child became a preferred option among educated women who grew up in cities. For women who grew up in rural areas and uneducated women, we observed a transition from higher parities to three-norm.

Antennapedia and optix regulate metallic silver wing scale development and cell shape in Bicyclus anynana butterflies.

Butterfly wing scales can develop intricate cuticular nanostructures that produce silver colors, but the underlying genetic and physical basis of such colors is mostly unexplored. Here, we characterize different types of wild-type silver scales in Bicyclus anynana butterflies and show that the varying thickness of the air layer between two cuticular laminas is most important for producing silvery broadband reflectance. We then address the function of five genes-apterous A, Ultrabithorax, doublesex, Antennapedia, and optix-in silver scale development by examining crispants with either ectopic gains or losses of silver scales. Simultaneous transformations of three parameters-loss of the upper lamina, increased lower lamina thickness, and increased pigmentation-occur when silver scales become brown and vice versa when brown scales become silver. Antennapedia and optix are high-level regulators of different silver scale types and determine cell shape in both sexes. Moreover, Antennapedia is involved in determining ridge and crossrib orientation.

Cover Image, Volume 139, Issue 28

The effect of chemical composition on the rheology of a reversible covalent bond containing polyethyleneimine (RCBP) was studied. RCBPs, also known as vitrimers, exhibit thermoplastic-like processability, but unlike thermoplastic polymers, their behavior is not driven by disentanglement. All the bonds undergo nearly simultaneous transformations at a constant average crosslink density. Therefore, no lower plateau is observed in a viscosity vs. shear rate plot. In the image created by Natanel Jarach and Naum Naveh, C-N bonds dissociate and rearrange as they “slide down” the plot. The reaction mechanisms were identified and explained. DOI: 10.1002/app.52353

Liquid Membranes in Catalysis

: The supported ionic liquid (SIL) membranes have demonstrated huge potential for numerous applications in current separation science and catalysis. Membrane technology allows for the separation of complex mixtures of gases, vapors, liquids and /or solids below trivial conditions. Simultaneous chemical transformations can also be achieved in membranes by using catalytically active materials comprising the membrane or embedded catalysts in the custom-built membrane reactors. In the present editorial, the remarkable contribution of liquid membranes in catalysis is highlighted. Some recent applications are presented and compared with conventional methods. In addition, SILs and their applications in catalysis, catalytic membranes, and recent advances in membrane separation processes are briefly described.

Formation and Chemical Transformations of Steel Corrosion Products in the Primary Systems of Nuclear Power Plants

Improvement of the corrosion situation during nuclear power plant (NPP) operation is associated with the enhancement of construction steel resistance against general (uniform) corrosion, with the routes of chemical transformations and corrosion product mass transfer in the coolant under different water chemistry conditions. Based on a look-back analysis of the obtained research results and a comparison of these results with those in available publications, the following conclusions were made: 1. The morphology of corrosion products formed on the inside surfaces of NPP systems has a four-layer structure. a. A layer of solid corrosion deposits tightly bonded with the surface is formed above the oxide film. b. Tightly bonded deposits are under loosely bonded (“loose” or dissipative) corrosive deposit layers that are dynamically balanced with the corrosion product particles dispersed in the water coolant. 2. By an aggregate state, the coarse/medium fractions (particle size more than 0.45 µm) and the fine fractions (particle size less than 0.45 µm) are conventionally referred to as nonsoluble and conditionally soluble corrosion products, respectively. 3. The chemical composition of all corrosion products depends on the presence of iron compounds, including the alloy element impurities (Cr, Ni, Mn, and Ti). 4. The radionuclide composition of all corrosion products is qualitatively the same and is presented by the activation products of reactor materials, such as 51Cr, 59Fe, 54Mn, 58Co, and 60Co. 5. The phase composition of solid corrosion products depends on the presence of ferrous (II) and ferric (III) iron oxide-hydroxide compounds whose ratio depends on water chemistry conditions: a. Under reducing water chemistry conditions, the phase composition of all corrosion products is determined by a spinel structure of magnetite (Fe3O4). b. Under oxidizing water chemistry conditions, the partial oxidation of ferrous (II) iron ions results in the formation of a defect structure of nonstoichiometric magnetite FeА 3+ [Fe2+ 1-хFe3+]BO4-х, where А and B are two nonequivalent positions in the magnetite structure. At х = 1, a nonstoichiometric magnetite structure changes into hematite, a α-Fe2O3 or maghemite γ-Fe2O3 structure. It is noted that the mathematical models nowadays used for describing the mass exchange and mass transfer of corrosion products in NPP primary systems do not consider physicochemical processes leading to the formation of such complex (phase, disperse, chemical, radionuclide) compositions of corrosion products. A widely known electrochemical mechanism that considers corrosion as a coupled anodic-cathodic process fails to explain actually observed steel dissolution and the contribution of soluble iron forms to oxide film formation on the corroding steel surface at potentials of cathodic polarization and anodic dissolution. This paper presents a diffusion model for corrosion product mass exchange and mass transfer in the steel-water coolant system as an alternative to the electrochemical model for general corrosion. This model is based on Frank-Kamenetkiy’s [Diffusion and Heat Transfer in Chemical Kinetics, Nauka (1987)] concept of the macroscopic kinetics of heterogeneous processes with simultaneous chemical transformations of the corrosion product ionic forms and the formation of solid-phase products in the water coolant and on the surface of corrosive steel. The diffusion model provided better insight into understanding how the phase, disperse, chemical, and radionuclide compositions of steel corrosion products are formed in the coolant of the NPP primary system.

Positron Annihilation Spectroscopy Study of Metallic Materials after High-Speed Cutting.

During high-speed cutting, a white layer is often produced on the machined surfaces after mechanical machining, seriously affecting the mechanical properties. These properties are related to the material structure and the defects induced by cutting. However, there is a lack of research on the atomic-scale defects of the white layer. This paper studied the influence of cutting parameters, namely the feed rate, cutting speed and cutting depth, on atomic-scale defects induced by high-speed cutting in GCr15 steel. Positron annihilation studies showed typical plastically deformed or tempered carbon steel defects with additional vacancy cluster components. The quantity of these clusters changed with cutting parameters. Furthermore, significant changes were observed in the subsurface region up to 1 µm, occurring as a result of simultaneous phase transformations, deformation and thermal impacts. The predominant accumulation of only one type of atomic-scale defect was not observed.

Simultaneous and sequential transformations with nucleation at preferred sites

The advent of new materials may increase transformations that involve two or more product phases. This transformation involving two or more product phases may occur simultaneously or sequentially. It is well-known that heterogeneous nucleation has advantages over homogeneous nucleation. Several sites may become preferred because they favor heterogeneous nucleation. The interface of precipitates and the grain boundaries are one of the preferred locations for nucleation. We model simultaneous and sequential transformations nucleated at the preferred sites. This work employs both computer simulation and exact analytical solutions. Two product phases, 1 and 2, were considered. The product phase 1 nucleated at the matrix/particle interface and the product phase 2 nucleated at the grain boundaries. The analytical model showed an excellent agreement with simulation data. For each case, computer simulation obtained the microstructural evolution. We discussed the effect of nucleation at the preferred sites on the microstructure.

Local transformations of multiple multipartite states

Understanding multipartite entanglement is vital, as it underpins a wide range of phenomena across physics. The study of transformations of states via Local Operations assisted by Classical Communication (LOCC) allows one to quantitatively analyse entanglement, as it induces a partial order in the Hilbert space. However, it has been shown that, for systems with fixed local dimensions, this order is generically trivial, which prevents relating multipartite states to each other with respect to any entanglement measure. In order to obtain a non-trivial partial ordering, we study a physically motivated extension of LOCC: multi-state LOCC. Here, one considers simultaneous LOCC transformations acting on a finite number of entangled pure states. We study both multipartite and bipartite multi-state transformations. In the multipartite case, we demonstrate that one can change the stochastic LOCC (SLOCC) class of the individual initial states by only applying Local Unitaries (LUs). We show that, by transferring entanglement from one state to the other, one can perform state conversions not possible in the single copy case; provide examples of multipartite entanglement catalysis; and demonstrate improved probabilistic protocols. In the bipartite case, we identify numerous non-trivial LU transformations and show that the source entanglement is not additive. These results demonstrate that multi-state LOCC has a much richer landscape than single-state LOCC.

5* Knowledge Graph Embeddings with Projective Transformations

Performing link prediction using knowledge graph embedding models has become a popular approach for knowledge graph completion. Such models employ a transformation function that maps nodes via edges into a vector space in order to measure the likelihood of the links. While mapping the individual nodes, the structure of subgraphs is also transformed. Most of the embedding models designed in Euclidean geometry usually support a single transformation type -- often translation or rotation, which is suitable for learning on graphs with small differences in neighboring subgraphs. However, multi-relational knowledge graphs often include multiple subgraph structures in a neighborhood (e.g.~combinations of path and loop structures), which current embedding models do not capture well. To tackle this problem, we propose a novel KGE model 5*E in projective geometry, which supports multiple simultaneous transformations -- specifically inversion, reflection, translation, rotation, and homothety. The model has several favorable theoretical properties and subsumes the existing approaches. It outperforms them on most widely used link prediction benchmarks

A two-tier junctional mechanism drives simultaneous tissue folding and extension.

During embryo development, tissues often undergo multiple concomitant changes in shape. It is unclear which signaling pathways and cellular mechanisms are responsible for multiple simultaneous tissue shape transformations. We focus on the process of concomitant tissue folding and extension that is key during gastrulation and neurulation. We use the Drosophila embryo as model system and focus on the process of mesoderm invagination. Here, we show that the prospective mesoderm simultaneously folds and extends. We report that mesoderm cells, under the control of anterior-posterior and dorsal-ventral gene patterning synergy, establish two sets of adherens junctions at different apical-basal positions with specialized functions: while apical junctions drive apical constriction initiating tissue bending, lateral junctions concomitantly drive polarized cell intercalation, resulting in tissue convergence-extension. Thus, epithelial cells devise multiple specialized junctional sets that drive composite morphogenetic processes under the synergistic control of apparently orthogonal signaling sources.

A Process Analytical Concept for In-Line FTIR Monitoring of Polysiloxane Formation.

The chemical synthesis of polysiloxanes from monomeric starting materials involves a series of hydrolysis, condensation and modification reactions with complex monomeric and oligomeric reaction mixtures. Real-time monitoring and precise process control of the synthesis process is of great importance to ensure reproducible intermediates and products and can readily be performed by optical spectroscopy. In chemical reactions involving rapid and simultaneous functional group transformations and complex reaction mixtures, however, the spectroscopic signals are often ambiguous due to overlapping bands, shifting peaks and changing baselines. The univariate analysis of individual absorbance signals is hence often only of limited use. In contrast, batch modelling based on the multivariate analysis of the time course of principal components (PCs) derived from the reaction spectra provides a more efficient tool for real-time monitoring. In batch modelling, not only single absorbance bands are used but information over a broad range of wavelengths is extracted from the evolving spectral fingerprints and used for analysis. Thereby, process control can be based on numerous chemical and morphological changes taking place during synthesis. “Bad” (or abnormal) batches can quickly be distinguished from “normal” ones by comparing the respective reaction trajectories in real time. In this work, FTIR spectroscopy was combined with multivariate data analysis for the in-line process characterization and batch modelling of polysiloxane formation. The synthesis was conducted under different starting conditions using various reactant concentrations. The complex spectral information was evaluated using chemometrics (principal component analysis, PCA). Specific spectral features at different stages of the reaction were assigned to the corresponding reaction steps. Reaction trajectories were derived based on batch modelling using a wide range of wavelengths. Subsequently, complexity was reduced again to the most relevant absorbance signals in order to derive a concept for a low-cost process spectroscopic set-up which could be used for real-time process monitoring and reaction control.

Time-dependent changes of arsenic and its selected forms in a hydroponic experiment with Quercus robur L.

Mutual transformations of particular As forms are dynamic. Therefore hydroponic experiments need to account for this variation. For this reason, the aim of the study was to determine the time-dependent changes of Astotal and selected forms of this metalloid (As(III), As(V), DMA or the sum of other organic forms) in modified Knop's solution and organs (root, low and high stem) of 2-year-old Quercus robur L. seedlings within a 33-day long hydroponic experiment. The results indicate the varying speed of As uptake and transport to aerial plant parts. A decrease in contents of As forms in organs of seedlings exposed to individual As forms varied, which indicates simultaneous transformations of As forms both in Knop's solution and plant organs. The obtained results indicate the need to analyse the main forms of As both in the nutrient solution and plant organs to assess the actual effectiveness of As phytoextraction by plants. It is necessary because, as demonstrated in this work, the addition of a specific As form does not mean that the capacity of a given plant relative to this form specifically is assessed. Capsule: The form of arsenic added to the medium undergoes dynamic changes affecting the phytoextraction of this metalloid in Quercus robur L. organs.

The perception of permafrost thaw in the Sakha Republic (Russia): Narratives, culture and risk in the face of climate change

This article focuses on the social representations of permafrost thaw among people who were born in different regions of the Sakha Republic (Russia) and live in the regional capital city of Yakutsk. Our research aims to obtain a better understanding of the new risk patterns associated to permafrost thaw through the collection and subsequent analysis of narratives of personal experiences in order to identify the main concerns, how these are defined and which coping strategies are considered by local inhabitants. Our respondents insightfully characterized the nature of the multiple interrelated processes and associations that they identified. According to locals' grasp, climate change and permafrost thaw's impacts exceed the merely physical and material dimensions, unchaining simultaneous and deep transformations in their culture. More specifically, physical degradation threatens their symbolic representations, the material practices and the emotional ties that they have developed in that specific land. They also expressed the need for potential mitigation strategies at both a regional and local scale.

The Crucible of War: Innovation in a Pandemic.

The Crucible of War: Innovation in a Pandemic.