Dominant Structure Research Articles

Effects of extraction methods on the physicochemical properties and functionalities of pectic polysaccharides from burdock (Arctium lappa L.)

In this work, the effects of four different extraction methods, acid (HCl), alkali (NaOH), enzymes (cellulase/pectinase), and buffer (pH 7.0) on the physicochemical properties and functionalities of burdock pectin were systematically investigated and compared. Buffer extraction gave a low yield (2.8 %) and is therefore limited in its application. The acid treatment hydrolyzed the neutral sidechains and gave a homogalacturonan content of 72.6 %. By contrast, alkali and enzymes preserved the sidechains while degrading the polygalacturonan backbone, creating a rhamnogalacturonan-I dominant structure. The branched structure, low molecular weight, and high degree of methylation (42.3 %) contributed to the interfacial adsorption, emulsifying capacity, and cellular antioxidant activity of the enzyme-extracted product. For the acid-extracted product, the strong intramolecular electrostatic repulsion restricted the formation of a contact interface to prevent coalescence of the emulsion. In addition, they did not have sufficient reducing ends to scavenge free radicals. Although a high branching size (5.0) was adopted, the low degree of methylation (19.5 %) affected the emulsifying capacity of the alkali-extracted products. These results provide useful information for pectic polysaccharides production with tailored properties.

Optimality Conditions in Uncertain Multi-Objective Optimization Problems with a Variable Domination Structure

In this paper, we first establish some new properties of a kind of nonlinear scalarization function. Second, based on set approaches, we introduce a class of new definitions of robustness for an uncertain multi-objective optimization problem with a variable domination structure. Finally, by applying the scalarization method, we obtain the necessary and sufficient optimality conditions of the robustness for the uncertain multi-objective optimization problem with a variable domination structure in a more general setting. Some of the obtained results extend and imply the corresponding ones in recent literature.

Christianity, Helping People in Poverty, and Embodied Relationships

AbstractThis article demonstrates that people animated by Christianity draw on faith to help people in poverty through building relationships. Contrasting with the literature that presents relationships as a means to change people, including through evangelizing, we find that relationships are conceived as an end in and of themselves. Drawing on an Australian ethnographic study with pastors and volunteers in church‐based community centers and people living in poverty, we illustrate how the realities of poverty subvert relationships. People in poverty prioritize their material needs. The challenges developing relationships notwithstanding, the article argues that elements of relationships found in this research represent an opportunity to advance knowledge of what it means to draw on faith to help people in poverty. Relationships can be a vehicle to change oppressive systems, but the capacity to do so must be assessed in the contexts of religion's position in dominant political and power structures.

Puzzling Structure of the Key Intermediates in Gold(I)-catalyzed Cyclization Reactions of Enynes and Allenenes.

We identify the dominant structures of the intermediates of gold(I)-catalyzed cyclizations of 1,5-enynes and 1,5-allenenes through computational analysis as gold(I) cyclopropylcarbenes, endocyclic vinylgold complexes and previously unreported non-classical carbocationic minima. In contrast to 1,6-enynes, the exocyclic carbocations are found to be less stable. Cyclopropylcarbene structures are consistently favoured as the most stable intermediates for all studied substitution patterns. We validate the computational methods used by using DLPNO-CCSD(T) energies as a benchmark, indicating that the B3LYP-D3 and M06-D3 functionals are most accurate for energy determination, while NPA charges are mostly insensitive to functional. The evolution of a 1,6-enyne in a single-cleavage or double-cleavage rearrangement is attributed to the barrierless evolution of a common cyclopropyl-gold(I) carbocation non-stationary geometry. Our findings provide insights into reaction pathways and substrate dependence of the cycloisomerization processes.

Articulating post-apocalyptic environmentalism: global civil society and the struggle for anti-colonial climate politics in the climate movement

ABSTRACT This article examines the dynamics of the climate movement’s (CM) engagement within global civil society (GCS), focusing on how this relates to its evolving commitment to anti-colonial climate politics and the wider, ongoing tensions between actors from the Global North and South within the movement. Here, this article contributes with a theorization on how counter-hegemonic and anti-colonial social movement alliances can be forged in GCS, building from neo-Gramscian, post- and decolonial concepts. This theorization builds on a study of the COP26 Coalition’s efforts in Glasgow in November 2021, exploring how the coalition strategically utilized post-apocalyptic environmentalism to amplify Southern and anti-colonial perspectives within the broader CM and to carve out a space for such perspectives within GCS. However, this study also highlights how GCS spaces are shaped by a neo-colonial global hegemony which fosters structures of Northern epistemic dominance which often function to de-legitimize, exclude, or co-opt non-Western knowledges and movements within GCS.

Mode transition mechanisms in semi-passive flapping-wing propulsion or energy extraction

To facilitate the smooth transition of operational modes in self-sustaining micro-thrusters, this study focuses on a device employing semi-passive flapping wings. Transient numerical methods are used to analyze the variation of flap energy acquisition and propulsion characteristics with pitching frequency, and the relationship between the dominant vortex structure and the force characteristics is analyzed by using the integral momentum theorem and the dynamic mode decomposition (DMD) method. The results indicate that, under the investigated operational conditions, with an increase in the pitching frequency, distinct wake evolution characteristics were observed. In the energy harvesting operational regime, the wake patterns manifest as 2P + mS, 2S + mS, and mS types. During the transitional phase from energy harvesting to propulsion, the wake patterns shift from 2S + mS to 2S transitional types, eventually leading to the manifestation of a reverse Karman vortex street (2S RBVK). In the propulsion operational regime, the wake patterns consist of a reverse Karman vortex street and asymmetric reverse Karman vortex street phenomena. Simultaneously, it was observed that the transition of flapping-wing performance from energy harvesting to propulsion conditions delays behind the transformation of vortex street structures. This delay is attributed to the necessity for the flapping-wing device to overcome its own resistance before generating a net effective propulsive force. The contributions of unsteady wake to thrust primarily encompass vortex thrust, thrust due to localized fluid acceleration, induced momentum force, and induced pressure force. As the pitching frequency increases, the influence of wake vortices on propulsion also intensifies. The contribution of wake vortices to flapping-wing propulsion is determined by the spatial distribution of Lamb vectors and localized fluid accelerations. The conclusions drawn from the dynamic modal analysis and reconstructed flow field analysis of wake vortices align with the findings of the investigation of wake vortices based on the integral momentum theorem.

Disturbance growth and its effect on convection in a buoyancy-driven vertical channel with one heated wall

Three-dimensional buoyancy-driven flow in a vertical channel with one heated wall that resembles a solar chimney is studied employing direct numerical simulation in order to capture the instability and disturbance growth in this flow. The aspect ratio of the simulated channel is 20, and the Grashof number is 6.1×1010. Linearly-unstable sinusoidal perturbations are individually applied to the pressure, velocity, and temperature fields at the entrance of the channel. It is shown that the imposed perturbations grow in time and change the characteristics of the flow from a laminar to a transitional character with a range of active scales of flow disturbances. Two dominant vortical structures identified in the transitional flow consist of two-dimensional spanwise and three-dimensional predominantly streamwise vortices, both growing spatially near the heated wall as the flow rises. For the ranges studied, both vortical structures appear to be independent of the amplitude or the type of the introduced perturbations. Budgets of the fluctuation kinetic energy show that buoyancy plays the main role in producing the fluctuating energy, although the role of shear production becomes more important as the flow rises along the channel. The effect of the disturbance growth on bulk convection in the solar chimney is to increase the friction coefficient, lowering the flow rate by 14% compared to a laminar condition. Moreover, the turbulent Prandtl number diverges significantly from unity near the heated wall, suggesting that the assumption of near-unity turbulent Prandtl number that is commonly made in Reynolds-averaged Navier–Stokes simulations of solar chimneys may lead to inaccurate predictions.

Temporal Tampering and “The Case for Reparations”

Abstract This essay examines Ta-Nehisi Coates's article “The Case for Reparations” to illuminate how he uses inventive temporal strategies to transform the grounds of the reparations debate. I argue, Coates engages in a process of temporal tampering that involves meddling with dominant temporal structures (conceptions of time that serve white supremacy) to accommodate the excessiveness of anti-Black violence. Through tactics of timeline jumping and a rhetoric of repair, Coates draws on articulations of time as a resource to sabotage anti-reparations temporalities. Instead of approaching the reparations debate through stale discursive entry points, such as financial logistics, I reveal how Coates draws upon conceptions of time to reposition reparations as a mode of worldbuilding and social transformation.

Trans* Joy as Resistance

Abstract Theorist Lauren Berlant defines inconvenience as an affect, one exerted by dominant forces onto subordinate populations. In the same way subordinate populations exert inconvenient affects as well, creating a dynamic of dominant and subordinate inconvenience through which social power relationships may be understood. Following this structure, this article charts the dominant and subordinate affects exerted by capitalism and trans* bodies, respectively, and how capitalist oppression responds to and shapes trans* embodiment. Through an autotheoretical lens, this relationship is here examined in the 2020 film Possessor and the 2015 film Tangerine, highlighting the points of interaction between trans*ness and capitalism's state structures of domination and oppression. Ultimately, I point to trans* joy as an affect that presents a danger to capitalism's domination, providing space for trans* persons to thrive.

Arbuscular mycorrhizal colonization of pioneer mangrove species in Mahakam Delta, East Kalimantan

Arbuscular mycorrhizal fungi (AMF) are symbiotic, with more than 80% of plant species in terrestrial and mangrove ecosystems. This study aimed to determine the level of AMF colonization on Avicennia lanata and its correlation with soil chemical properties. Sampling was conducted in Sepatin Village, located in Mahakam Delta. There are four sampling locations, three were mangrove rehabilitation areas (A, B, and C), and one was a mangrove natural forest (MNF). Root samples were taken from four A. lanata seedlings purposively selected at each location. The roots were stained with 0.05% trypan blue, and the mycorrhizal structures of the roots were observed using a compound microscope. The results showed that the percentage of AMF colonization with A. lanata in MNF was higher (97%) than in other locations. Internal hyphae were the dominant structure found in the root of A. lanata in all locations, with a percentage of 76.61%. AMF root colonization negatively correlated with N-total, C-organic, and available P. In contrast, Ca, Mg, K, Na, and CEC positively correlated with AMF root colonization. The colonization of AMF in the root of A. lanata may promote the early growth of seedlings, and the application of AMF can support rehabilitating mangrove degraded.

Precursory Analysis Ensemble Spread Signals That Foreshadow Stratospheric Sudden Warmings

Abstract This study conducts a thorough investigation into the behaviors of analysis ensemble spreads linked to stratospheric sudden warming (SSW) events. A stratosphere-resolving ensemble data assimilation system is used here to document the evolution of analysis spread leading up to a pair of warming events. Precursory signals of the increased ensemble spreads were found a few days prior to two SSW events that occurred during December 2018 and August–September 2019 in the Northern and Southern Hemispheres, respectively. The signals appeared in the upper and middle stratosphere and did not appear at lower heights. When the signals appeared, it was found that both tendency by forecast and analysis increment in a forecast-analysis (data assimilation) cycle simultaneously became large. An empirical orthogonal function analysis showed that the dominant structures of the precursory signals were equivalent barotropic and were 90° out-of-phase with the analysis ensemble-mean field. Over the same period, the upper and middle stratosphere became more susceptible to barotropic instability than in their previous states. We conclude that the differing growth of barotropically unstable modes across ensemble members can amplify spread during the lead-up to SSW events. Significance Statement Winds in the winter stratospheric polar vortex are typically westerly. Occasionally, however, warming over the pole leads to a reversal of the flow through a process known as stratospheric sudden warming. These events are difficult to predict even in state-of-the-art analysis and forecasting systems. In this study, we identify a precursor signal in the form of increased ensemble spread that appears to originate from differing realizations of growing barotropic modes across the ensemble. This signal could serve as a useful forecasting tool by enhancing situational awareness in the lead-up to potential stratospheric sudden warming events.

Hydrogen bonding switched symmetric and anti-symmetric vibrations SRS of –CH2 in aqueous DEG solution

The symmetric and anti-symmetric stretching vibrations of C–H extensively exist in organic molecules, which constantly arise together in Raman spectroscopy. In this study, a method was presented to switch stimulated Raman scattering peak from symmetric vibrations (2870 cm−1) to anti-symmetric vibrations (2924 cm−1) of –CH2 by regulating the hydrogen bonding (HB) associated through intermolecular and intramolecular in diethylene glycol (DEG) molecules. Such dominant association structure can be converted from DEG-DEG to DEG-H2O in the aqueous DEG solutions. The interaction between H2O and DEG was investigated through the density functional theory calculation. The changes in intermolecular HB have effects on the intramolecular vibrational modes by the intermolecular forces and symmetry of the DEG molecule. This study has exciting potential prospect and can be extended to other mixing solutions.

Analysis of the Dominant Structures of an Impinging Round Jet at M=0.9

Large-eddy simulation of subsonic round jet impinging on a flat circular plate is performed at Mach number 0.9 and Reynolds number 25,000, based on the diameter and centerline velocity of the jet for two impingement distances h of 6r0 and 8r0 using high-order compact finite difference scheme. The complex flow phenomena associated with the impinging jet flowfield are studied. The power spectral density (PSD) of instantaneous pressure reveals a discrete impingement tone. Dynamic mode decomposition (DMD) of the velocity and pressure is also done for both cases to extract the most dominant modes of the flow. The fundamental impingement tone frequency obtained from the PSD of pressure is identical to that of the first dominant pressure mode obtained from DMD. Both axisymmetric and semihelical modes are present for the h=8r0 case, but only axisymmetric modes are there in the h=6r0 case, and it is noted that the modes corresponding to the fundamental tone have an axisymmetric structure. Also, one dominant mode showing the wall jet structures denoting the liftoff of fluid from the wall after impingement at some radial distance away from the stagnation region is present in both impingement distance cases.

Tuning dynamic mechanical properties of Cu50Zr50 nanoglasses/ nanopolycrystalline Cu composites investigated by molecular dynamics simulation

Nanoglasses/nanopolycrystalline (NGNP) composites have emerged as a promising approach to balance the strength and plasticity of metallic glasses. Herein, the shock responses of five Cu50Zr50 NGNP composites are investigated via molecular dynamics simulations under a shock velocity of 0.5 to 2.0 km/s. The simulation results reveal that with an increasing fraction of nanocrystalline grains, the Hugoniot pressure, shear stress, and spall strength of the composites are enhanced, while their atomic strain decreases under shock loading. Additionally, due to the dominant structure type changes from an amorphous structure to a crystal structure, the deformation mechanism transforms from the growth of shear transformation zones to dislocation slip, phase transition, and amorphization as the impact velocity increases. In terms of the spallation, the spall strength of the composites rises initially and then declines due to the competing mechanisms of strain rate hardening and shock-induced softening.

The Secondary Structure of Potato Spindle Tuber Viroid Determines Its Infectivity in Nicotiana benthamiana.

The function of RNAs is determined by their structure. However, studying the relationship between RNA structure and function often requires altering RNA sequences to modify the structures, which leads to the neglect of the importance of RNA sequences themselves. In our research, we utilized potato spindle tuber viroid (PSTVd), a circular-form non-coding infectious RNA, as a model with which to investigate the role of a specific rod-like structure in RNA function. By generating linear RNA transcripts with different start sites, we established 12 PSTVd forms with different secondary structures while maintaining the same sequence. The RNA secondary structures were predicted using the mfold tool and validated through native PAGE gel electrophoresis after in vitro RNA folding. Analysis using plant infection assays revealed that the formation of a correct rod-like structure is crucial for the successful infection of PSTVd. Interestingly, the inability of PSTVd forms with non-rod-like structures to infect plants could be partially compensated by increasing the amount of linear viroid RNA transcripts, suggesting the existence of additional RNA secondary structures, such as the correct rod-like structure, alongside the dominant structure in the RNA inoculum of these forms. Our study demonstrates the critical role of RNA secondary structures in determining the function of infectious RNAs.

Structural and metamorphic evolution of a subducted passive margin: insights from the Briançonnais nappes of the Western Alps (Ubaye–Maira valleys, France–Italy)

This contribution analyses the structural architecture and tectono-metamorphic evolution of Briançonnais units in the southern French-Italian Western Alps. The studied area extends from a virtually non-metamorphic area adjacent to the Helvetic-Dauphinois External Domain in the west to the Monviso-Queyras ocean-derived units in the east, where metamorphism increases up to eclogite-facies. Mapping at the scale 1:10.000 of a mountainous part of the Ubaye-Maira transect was performed, which portrays in detail the Briançonnais units over ~ 100 km2. The lithologies include meta-andesite, meta-siliciclastics, marbles, turbiditic calcschists and flysch whose age spans from Late Carboniferous to Eocene. Metamorphism is low-grade greenschist-facies in the west but reaches the blueschist-facies to the east. Structures related to four phases of deformation are identified. The first two generations of structures (D1–D2), related to the original top-to-the-west nappe stacking, are associated with conditions close to the peak of Alpine metamorphism. Previous tectonic surfaces are transposed by the dominant deformation structures (D3), developed under retrograde/decompression conditions. This D3 corresponds to a backfolding and back-thrusting event with a top-to-the-E transport. A fourth phase (D4) developed during late low-grade metamorphic conditions and deforms the previous surfaces by locally developing a crenulation cleavage, followed by brittle tectonics. An updated metamorphic map is presented, backed on published estimates and new thermometric data obtained by Raman Spectroscopy of Carbonaceous Material (RSCM). The TRSCM values range from ~ 295 °C to > 350 °C, moving from the most external Briançonnais unit to the internal Queyras “Schistes Lustrés” units. Suspected Upper Cretaceous palaeofaults have been documented, allowing us to group the classic Aiguille de Mary and Ceillac (sub-) units into a single tectonic unit, here referred to as Maurin unit. The palaeogeographical reconstruction of the evolution of the studied transect highlights the importance of the Marinet and Maurin axial units in the feeding of the Late Cretaceous-Eocene breccias deposited on the more internal Acceglio-type units.

Processing and characterization of TiNbMoTaW refractory high entropy alloy by mechanical alloying

Refractory High Entropy Alloys (RHEAs) are a new class of alloys that have attractive properties suited for high-temperature applications. An equiatomic combination of the elements Ti, Nb, Mo, Ta, and W has been processed by mechanical alloying (MA) route to yield TiNbMoTaW RHEA powder. Structural analysis of RHEA powder obtained after 100 h of mechanical milling, indicated the formation of a single-phase solid solution with a body-centered cubic (BCC) structure and has a lattice constant of 3.1645 Å. CALPHAD modeling of TiNbMoTaW RHEA was carried out to understand the effect of phase changes with respect to temperature. RHEA was found to be thermally stable at elevated temperatures with a dominant BCC structure, which highlights its potential in high-temperature engineering applications.

Designer biochar with specific functionalities for the sustainable mining of invaluable metals from sea water: Performance assessment, mechanism insights and cost benefit analysis

Resource efficiency and cleaner production are an integral component of sustainable development. The present research addresses three contemporary issues. Firstly, quest for a greener alterative to land based mining-seawater, secondly, translation of renewable biowastes into carbon negative biochar and thirdly, synthesis of organic salts of metals directly from metal laded biochar. Sea water is an untapped source of invaluable elements leading to rising momentum for various new technologies. Herein, neem cake is tailored specifically for selective recovery of magnesium and strontium ions from simulated sea water in both batch and continuous systems. Magnesium selective biochar is prepared by insitu pyrolysis at 700℃ using sodium bicarbonate and urea as green porogen and nitrogen source whereas strontium selective biochar is prepared by direct pyrolysis at 700℃ followed by encapsulating alginate microspheres within the biochar lattice. Batch studies revealed the maximum adsorption capacities and removal efficiencies of 34.08 mg/g and 95 % for strontium(S-BC) and 40.2 mg/g and 98 % for magnesium(M−BC). The analytics reveals biochars as fine-tuned mesoporous carbon dominant structure with several N and O functionalities suggesting complexation, H-bonding as the adsorption mechanism. The Sips and PNO models surpassed all isotherm and kinetic models and well describes the process kinetics as chemisorption along with film diffusion as main contributors respectively. In column studies, effect of different process parameters is investigated and it is observed that experimental data corelates well with the BDST model. Moreover, scale up approach is employed to predict large scale design parameters. Lastly, citric acid as a green chelating agent is utilized to recover metal ions in the form of citrates and regenerate spent biosorbent along with detailed cost benefit analysis, thereby endorsing the circular economy approach.

Population of Collembola of bog ecosystems of the ukrainian part of the International Biosphere Reserve «Roztochia»

A comparative analysis of the taxonomic and ecological structure of bog collembolan taxocenes of IBR "Roztochia" was carried out. 67 species of Сollembola belonging to 43 genera and 12 families were found on the studied territory. The representation of the rare element of collembolofauna (its uniqueness) is 14.9%. Three species are new to the collembolofauna of Ukraine (Cryptonura kühnelti, Heteromurus sexoculatus, Isotomurus fucicolus) and one new species is from the continental part of Ukraine (Tetracanthella proxima). From 1 to 13 species of Сollembola were found at the level of point alpha diversity, and 5–29 species of coenotic alpha diversity, which indicates a small capacity of the soil environment for Сollembola in bog ecosystems, сompared to forest and meadow ecosystems. The investigated bog Collembola taxocenes are characterized by small and average population density indicators, from 0.25 to 9.1 thousand spec./m2. It was found that the structure of dominance, spectra of life forms and biotope groups of the studied taxocenes have their own specificity, due to local edaphic conditions. The analysis of the ecological structure showed that, in terms of species richness, complexes of hygro-mesophilic (31.3% of the total species richness), mesophilic (22.4%) and xeroresistant forms (20.9%) prevail in bog taxocenes of collembola. The studied taxocenes include nine biotope groups of species. The biotope groups of forest species (28,9%) and species that differentiate the bog type of ecosystems (bog, near-water, meadow- and forest-bog species) prevails. The share of representatives of the second group in the studied taxocenes is 14.9% of the total species diversity and 29.5% of the total abundance. It was established that a mixed collembolan taxocene is formed in bog ecosystems, where none of the biotope groups reaches 40% of the total abundance.

Taxonomic and ecological structure of oribatid mites (Acari: Oribatida) of mesophilic grasslands on the Transcarpathian lowland

The article analyzes the taxonomic diversity, dominance structure, spectra of morpho-ecological types, biotope complexes and groups of oribatid mites of mesophilic grasslands on Transcarpathian lowland. Prior to our works, there were almost no studies of the oribatid communities of the studied area. The research plots located on the sorrounding areas of the city of Mukachevo and the village of Kalnyk of the Mukachevo district. Soil samples selected for 2013-2014. The geographical coordinates of the first meadow are: 48º22.79' N, 22º40.14' E, and the second one is 48º30.86' N, 22º34.65' E. The total area of the first biotope is 0.45, and the second is 37.5 hectares. In relation to the humidity of the substrate, this type of biotope is characterized by mesophilic conditions. Extraction of mites from soil was carried out using Tullgren funnel method. Permanent preparations were prepared. Identification of the specimens was carried out using a microscope (Olympus BX 51). Oribatid mites of the investigated mesophilic grasslands are represented by 26 species from 22 genera and 16 families. The families Oppiidae and Scheloribatidae are the most represented. The average density of oribatid mites of the mesophilic grasslands on Transcarpathian lowland has relatively small values (3.7 thousand specimens per m2). The dominant species include Punctoribates punctum (C. L. Koch, 1839) and Ceratozetes mediocris Berlese, 1908. They together make up 44% of the total density of oribatids. Margalef, Menkhinik, Simpson, Shannon and Berger-Parker indices were calculated. 10 morpho-ecological types of oribatid mites were found on mesophilic grasslands. Oribatids - inhabitants of small soil crevices – predominate. Representatives of five biotope complexes (euryoecic, hygrophilous, hygro-mesophilous, mesophilous and xerophilous) and four biotope groups (eurytopic, forest, forest-meadow, meadow) were identified in the structure of ecological groups of Oribatids. Mesophilous and meadow species of oribatid mites have the largest share.