Unique Interaction Mechanism Research Articles

Gradient structured Al alloy with a synergistic improvement of strength-ductility obtained by friction stir processing

One Al 6061 with gradient microstructure is prepared by friction stir processing (FSP). Microscopic characterization indicates that the regulation of grain size gradient could be achieved by adjusting the process parameters of FSP. The mechanical property test indicates that one gradient Al 6061 combines an ultimate tensile strength of 266 MPa with a uniform elongation of 27 %, and the other comes 258 MPa with 29 %, which provides an excellent combination of strength and ductility. Moreover, the molecular dynamics (MD) method is employed to reconstruct and simulate the mechanical behavior of the gradient region and the dynamic evolution of the microstructure. When the stacking faults (SFs) with antisymbolic Burgers vector meet and detwinning occurs, grain refinement will induce localized strengthening. When the Shockley partials occur cross-slip, numerous sessile dislocations obstruct the dislocation motion more facilitate strain hardening. Meanwhile, a unique interaction mechanism between shear bands (SBs) and intergranular cracks in Al 6061 is discovered in plastic deformation. The coarse net-like SBs in the small-grain region are highly susceptible to catastrophic fracture of the material, and the large cracks formed within the severely band-like SBs in the large-grain region weaken the strength substantially. However, the formation of sessile dislocations in the gradient region effectively mitigates strain localization and inhibits the nucleation of large cracks. The results interpret the dynamic evolution process of gradient microstructure prepared by FSP and the mechanism of strengthening and toughening and provide process and theoretical references for the research and development of new engineering materials.

Blocking huntingtin oligomers from binding lipid membranes improves phenotype in a C. elegans model of Huntington's disease.

As protein aggregation is the defining hallmark of all amyloid diseases, a common therapeutic strategy is to develop molecules that inhibit aggregation. However, this approach has yielded limited success. Many amyloid proteins directly interact with lipid membranes. These interactions promote distinct aggregation pathways and often result in membrane damage leading to toxicity. As a result, directly targeting the ability of amyloids to bind lipid membranes represents a novel therapeutic strategy. As a proof of principle, the interaction between lipid membranes and mutant huntingtin (htt) aggregates was used to test this strategy. Using a colorimetric lipid binding assay over 1200 compounds were screened for their ability to block htt/lipid binding. The screen was set up to only identify compounds that directly interacted with htt, not the lipid membrane. Two promising compounds Ro-90-7501 and Benzamil hydrochloride were identified. Validation was achieved via two additional methods, a calcein dye leakage assay and in situ atomic force microscopy (AFM). As these compounds directly interact with htt, ThT and AFM assays were performed to assess their impact on aggregation. Ro-90-7501 had a slight inhibitory effect on fibril formation, but aggregate morphologies were unchanged. Benzamil did not inhibit fibril formation; however, oligomer precursors were significantly smaller when exposed to Benzamil. Molecular dynamic simulations (MD) revealed that the two compounds have unique mechanisms of interaction with htt aggregates. Having established that the compound prevented htt from binding membranes, a C. elegans model of Huntington's disease was used to determine if this strategy could alleviate phenotype. Despite have a minimal impact on punctate formation, both compounds reduced a thrashing deficit in animals caused by mutant htt expression, suggesting that this strategy reduces htt toxicity.

МИКРОБНЫЕ СООБЩЕСТВА КАРСТОВЫХ ПЕЩЕР

Special geochemical, hydrological and microclimatic conditions in karst caves lead to the development of unique bacterial communities in them. The microbiota of such communities has complex, often unique mechanisms of interaction, which currently does not allow us to fully identify their species composition. Among the bacteria in caves, the most common are representatives of Alfaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Actinobacteria. Lack of light, lack of nutrients and low temperatures lead to a number of adaptations in bacteria, such as a decrease in cell size, slow metabolism, changes in membrane lipids and enzymes, and a number of others. In aphotic conditions, the basis of trophic chains are chemolithotrophic bacteria. The development of bacteria occurs mostly on the surface of mineral formations, soil, walls and in the upper layer of water. Rocky surfaces of caves represent the largest areas potentially suitable for colonization by microbial communities. There is a widespread assumption among researchers that the bacteria living on the walls are mostly cave microbiota and are the least susceptible to changes under anthropogenic load. Bacteria are actively involved in the geochemical transformations of the environment: corrosion of rocks the subsequent deposition of mineral formations. At present, the hypothesis of biogenic mineralization is generally accepted. On the one hand, crystal formation occurs with the participation of only living microorganisms, on the other hand, a change in the physicochemical conditions of the environment is of no small importance in this process. A significant role, according to researchers, is played by secreted extracellular substances that induce passive mineralization or, conversely, cause the dissolution of calcite. In addition, it is known that microorganisms isolated from caves, while remaining viable, after some time lose their ability to form or destroy mineral formations. Bacteria involved in the transformation of mineral substrates are not confined to taxonomic groups and act as part of multispecies communities.

Design of Mobile-Based Geographic Information System Potential of Agricultural Land in Sub-District Completed

Communication The rapid development of information technology provides tremendous benefits to the community. For this reason, an application is needed to make it easier for people to get information. Various techniques, methods, and new approaches are implemented to improve and develop technology in an effort to obtain fast, precise, and accurate geographic information. A system must have the ability so that the system can be said to be useful for its users. A GIS must have at least four capabilities, namely the ability to manipulate attributes, and the ability to display input and output using images. Mobile applications have a user interface with a unique interaction mechanism provided by the mobile platform. Mobile applications have also been specifically designed for mobile platforms (eg IOS, Android, or Windows Mobile).

Microstructure and catalytic properties of Fe3O4/BN, Fe3O4(Pt)/BN, and FePt/BN heterogeneous nanomaterials in CO2 hydrogenation reaction: Experimental and theoretical insights

Hexagonal boron nitride (h-BN) nanosheets are a promising material for various applications including catalysis. Herein, h-BN-supported Fe-based catalysts are characterised with respect to CO2 hydrogenation reaction. Heterogeneous Fe3O4/BN, Fe3O4(Pt)/BN, and FePt/BN nanostructures are obtained via polyol synthesis in ethylene glycol. The sizes of Fe3O4 nanoparticles and their distributions over h-BN surfaces depend on the amount of H2PtCl6 added to the synthesis media. Bimetallic FePt nanoparticles are formed when Pt content is high enough. In situ TEM analysis shows the formation of core–shell h-BN@FePt nanoparticles during heating that prevents FePt NPs from further sintering during the catalytic process. The mechanism of Fe and Pt interaction is elucidated based on the molecular dynamic simulations. The FePt/BN nanomaterials show significantly higher CO2 conversion rate compared to the Fe3O4/BN and Fe3O4(Pt)/BN heterogeneous nanomaterials and exhibit almost 100% selectivity to carbon monoxide. The Fe3O4/BN and Fe3O4(Pt)/BN nanomaterials show better selectivity to hydrocarbons. The possible reaction pathways are discussed based on the calculated sorption energies of all reactants, intermediate compounds, and reaction products. The study highlights pronounced catalytic properties of the developed system and reveals a unique interaction mechanism between its components increasing their stability.

Structural characterization of the interaction between α M I‐domain of the integrin Mac‐1 (α M β 2 ) and the cytokine pleiotrophin

Integrin receptors are involved in numerous physiological processes, including inflammation, cell migration, extracellular matrix recognition, survival, and growth. Integrin Mac-1 (αMβ2) is a monocyte adhesion receptor that can undergo rapid activation yielding conformational changes that subsequently allow increased affinity for its ligands and enable cellular responses such as rolling, adhesion, and transmigration of phagocytes to the inflammatory sites. αMβ2 is also the most promiscuous integrin receptor because it recognizes a large number of distinct ligands that share no homologous recognition motif. In particular, αMI-domain is known to bind cationic proteins/peptides depleted in acidic residues. This contradicts the canonical ligand-binding mechanism of αI-domains, which requires an acidic amino acid in the ligand to coordinate the divalent cation within the metal ion-dependent adhesion site (MIDAS) of αI-domains. The lack of acidic amino acids in the αMI-domain-binding sequences suggests the existence of an as-yet uncharacterized interaction mechanism. In the present study, we analyzed interactions of αMI-domain with a representative Mac-1 ligand, the cationic cytokine pleiotrophin (PTN). Through nuclear magnetic resonance (NMR) chemical shift perturbations, cross saturation, and nuclear Overhauser effect spectroscopy (NOESY), we found the interaction between αMI-domain and PTN is divalent cation-independent and mediated mostly by hydrophobic contacts between the N-terminal domain of PTN and residues in the α5-β5 loop of αMI-domain. The mutation I265 in the α5-β5 region confirms this area as a binding site of αMI-domain for PTN. The observation that both increased ionic strength and mutations of acidic residues in the α5-β5 loop weaken the interaction between the proteins indicates electrostatic interaction may also play a significant role in the binding. Based on results from these experiments, we formulated a model of the interaction between αMI-domain and PTN. This unique mechanism of interaction between PTN and αMI-domain should explain ligand recognition specificity of αMβ2.

Diversified Psychological Mechanisms in the Formation of Tourist Destination Attachment

Since destination attachment is a new branch in the field of place attachment, studies are lacking on the formation mechanisms of destination attachment. The psychological processes underlying the mechanism have also been ignored. This study adaptively applied the grounded theory to the online travel blogs of Hainan in China, aiming to identify the unique interaction mechanism of psychological dimensions in the formation of a destination attachment. Three different psychological paths were revealed, namely, “cognition→affect→conation,” “conation→cognition→affect,” and “affect→conation→cognition.” The formation of destination attachment was found to be similar to consumer knowledge learning. The problems of paradigm integration and the expansion of the destination attachment source were also considered in this research.

Designing Novel Zn-Decorated Inorganic B12P12 Nanoclusters with Promising Electronic Properties: A Step Forward toward Efficient CO2 Sensing Materials.

Gas sensing materials have been widely explored recently owing to their versatile environmental and agriculture monitoring applications. The present study advocates the electronic response of Zn-decorated inorganic B12P12 nanoclusters to CO2 gas. Herein, a series of systems CO2–Zn–B12P12 (E1–E4) are designed by adsorption of CO2 on Zn-decorated B12P12 nanoclusters, and their electronic properties are explored by density functional theory. Initially, placement of Zn on B12P12 delivers four geometries named as D1–D4, with adsorption energy values of −57.12, −22.94, −21.03, and −14.07 kJ/mol, respectively, and CO2 adsorption on a pure B12P12 nanocage delivers one geometry with an adsorption energy of −4.88 kJ/mol. However, the interaction of CO2 with D1–D4 systems confers four geometries named as E1 (Ead = −75.12 kJ/mol), E2 (Ead = −25.89 kJ/mol), E3 (Ead = −42.43 kJ/mol), and E4 (Ead = −28.73 kJ/mol). Various electronic parameters such as dipole moment, molecular electrostatic potential analysis, frontier molecular orbital analysis, QNBO, global descriptor of reactivity, and density of states are also estimated in order to understand the unique interaction mechanism. The results of these analyses suggested that Zn decoration on B12P12 significantly favors CO2 gas adsorption, and a maximum charge separation is also noted when CO2 is adsorbed on the Zn–B12P12 nanocages. Therefore, the Zn-decorated B12P12 nanocages are considered as potential candidates for application in CO2 sensors.

Localization and characterization of delamination in laminates using the local wavenumber method

This paper proposes a method to effectively locate and characterize mode I delamination in carbon fiber/epoxy (CF/EP) composite laminates using the local wavenumber method of propagating guided waves in a fine grid of spatial sampling points. Mode I interlaminar fracture tests were conducted using a double cantilever beam (DCB) specimen to evaluate the developed method. Wave propagation in composite laminates with delamination at different center frequencies were investigated by two-dimensional finite element (FE) simulation. The results revealed some unique mechanisms of interaction between guided wave and delamination in detail. They demonstrated that the wave propagation velocity is transformed at the delamination, and the wave attenuation and dispersion are larger with the increase of the center frequency. The guided waves were rapidly excited at each grid point using a non-contact scanning laser Doppler vibrometer (SLDV) system and actuated by a single fixed piezoelectric (PZT) sensor in the experimental study. The spatially dependent wavenumber value of the center frequency was determined by the local Fourier domain analysis method for processing guided wave filed data. The results showed that the local wavenumber method for guided waves is capable of locating and characterizing the delamination in composite laminates.

Многоликий и коварный вирус герпеса человека 6А/В: как найти и обезвредить?

Herpesvirus infections are one of the most common groups of human infectious diseases. Having unique mechanisms of interaction with the human immune system, they can persist in the organism for a long time and can be reactivated by immunosuppressive factors. Human herpesvirus 6A/B (HHV-6A/B) is one of the most common but still insufficiently studied viruses affecting children. There are several variants of HHV-6 infection, including acute primary infection (primarily in young children, manifesting itself with sudden exanthema and febrile convulsive seizures), latent primary infection (manifesting itself with non-immune neutropenia), reactivation of latent infection (in children of pre-school and school age, primarily developing as respiratory infection and infectious mononucleosis), and chromosomally integrated form. This article discusses the issues of epidemiology, clinical mani-festations, diagnosis, and treatment of HHV-6A/B infection in children. Key words: herpesvirus infection, human herpes virus 6, children, diagnosis, treatment

Efficient Production of Multi-Layer Graphene from Graphite Flakes in Water by Lipase-Graphene Sheets Conjugation

Biographene was successfully produced in water from graphite flakes by a simple, rapid, and efficient methodology based on a bioexfoliation technology. The methodology consisted in the application of a lipase, with a unique mechanism of interaction with hydrophobic surfaces, combined with a previous mechanical sonication, to selectively generate lipase-graphene sheets conjugates in water at room temperature. The adsorption of the lipase on the graphene sheets permits to keep the sheets separated in comparison with other methods. It was possible to obtain more than 80% of graphene (in the form of multi-layer graphene) from low-cost graphite and with less damage compared to commercial graphene oxide (GO) or reduced GO. Experimental analysis demonstrated the formation of multi-layer graphene (MLG) mainly using lipase from Thermomyces Lanuginosus (TLL).

Impact of tourist-to-tourist interaction on tourism experience: The mediating role of cohesion and intimacy

Utilizing the Stimulus-Organism-Response paradigm, this study explores how self-disclosure, an important component of tourist-to-tourist interaction, influences tourist experience. Data were collected through a field experiment and analyzed via PLS analysis and PROCESS. Findings indicate that self-disclosure indirectly increases engagement by strengthening perceived cohesion and perceived intimacy. Perceived cohesion and perceived intimacy have indirect effects on satisfaction with experience, through engagement. Further, the initial tie strength moderates the effect of self-disclosure on perceived cohesion and perceived intimacy. These findings contribute to the development of tourism experience research from the perspective of tourist-to-tourist interaction and the social interaction literature by examining the unique interaction mechanism among tourists.

A study of the small-molecule system used to investigate the effect of arginine on antibody elution in hydrophobic charge-induction chromatography

Hydrophobic charge-induction chromatography (HCIC) using 4-mercaptoethylpyridine (4-MEP) as the ligand is used to purify antibodies. The 4-MEP resin ligand has high affinity for antibodies, which makes it difficult to optimize the elution conditions. Recent studies showed that arginine is effective at eluting and purifying antibodies using the HCIC with 4-MEP. In the present study, we investigated the mechanism of the action of arginine on the interaction between butyl gallate (BG) and the 4-MEP resin as a model system for protein–4-MEP interactions. Equilibrium adsorption experiments showed that arginine has a significant effect on the desorption of BG from the 4-MEP resin and, in fact, is found to exhibit a greater effectiveness than guanidine and urea, which are known denaturants. The calculated binding free energy between a BG molecule and a 4-MEP resin ligand molecule using molecular dynamics simulations was qualitatively consistent with the experimental results. A principal component analysis of the simulations showed that arginine molecules intervene in the interaction between the BG and 4-MEP molecules at a distance of 8.5 Å by entering the space between the phenol and pyridine planes. The present results suggest that arginine has a unique mechanism of interaction with the phenol–pyridine system, which should be associated with the effects of arginine on the protein–4-MEP systems.

In-situ weak-beam and polarization control of multidimensional laser sidebands for ultrafast optical switching

All-optical switching has myriad applications in optoelectronics, optical communications, and quantum information technology. To achieve ultrafast optical switching in a compact yet versatile setup, we demonstrate distinct sets of two-dimensional (2D) broadband up-converted multicolor arrays (BUMAs) in a thin type-I β-barium-borate crystal with two noncollinear near-IR femtosecond pulses at various phase-matching conditions. The unique interaction mechanism is revealed as quadratic spatial solitons (QSSs)-coupled cascaded four-wave mixing (CFWM), corroborated by numerical calculations of the governing phase-matching conditions. Broad and continuous spectral-spatial tunability of the 2D BUMAs are achieved by varying the time delay between the two incident pulses that undergo CFWM interaction, rooted in the chirped nature of the weak white light and the QSSs generation of the intense fundamental beam. The control of 2D BUMAs is accomplished via seeding a weak second-harmonic pulse in situ to suppress the 2D arrays with polarization dependence on the femtosecond timescale that matches the control pulse duration of ∼35 fs. A potential application is proposed on femtosecond all-optical switching in an integrated wavelength-time division multiplexing device.

Unique Mechanism of the Interaction between Honey Bee Toxin TPNQ and rKir1.1 Potassium Channel Explored by Computational Simulations: Insights into the Relative Insensitivity of Channel towards Animal Toxins

BackgroundThe 21-residue compact tertiapin-Q (TPNQ) toxin, a derivative of honey bee toxin tertiapin (TPN), is a potent blocker of inward-rectifier K+ channel subtype, rat Kir1.1 (rKir1.1) channel, and their interaction mechanism remains unclear.Principal FindingsBased on the flexible feature of potassium channel turrets, a good starting rKir1.1 channel structure was modeled for the accessibility of rKir1.1 channel turrets to TPNQ toxin. In combination with experimental alanine scanning mutagenesis data, computational approaches were further used to obtain a reasonable TPNQ toxin-rKir1.1 channel complex structure, which was completely different from the known binding modes between animal toxins and potassium channels. TPNQ toxin mainly adopted its helical domain as the channel-interacting surface together with His12 as the pore-blocking residue. The important Gln13 residue mainly contacted channel residues near the selectivity filter, and Lys20 residue was surrounded by a polar “groove” formed by Arg118, Thr119, Glu123, and Asn124 in the channel turret. On the other hand, four turrets of rKir1.1 channel gathered to form a narrow pore entryway for TPNQ toxin recognition. The Phe146 and Phe148 residues in the channel pore region formed strong hydrophobic protrusions, and produced dominant nonpolar interactions with toxin residues. These specific structure features of rKir1.1 channel vestibule well matched the binding of potent TPNQ toxin, and likely restricted the binding of the classical animal toxins.Conclusions/SignificanceThe TPNQ toxin-rKir1.1 channel complex structure not only revealed their unique interaction mechanism, but also would highlight the diverse animal toxin-potassium channel interactions, and elucidate the relative insensitivity of rKir1.1 channel towards animal toxins.

Delamination detection in composite beams using pure Lamb mode generated by air-coupled ultrasonic transducer

The interaction of Lamb wave A0 mode with delamination and delamination detection in 16-ply carbon fiber–reinforced epoxy composite beams are investigated through three-dimensional finite element simulation and experimental studies in this article. Wave propagation in composite beams with delamination with different lengths and located at different interfaces are investigated in finite element simulations, and some unique mechanisms of interaction between A0 mode and delamination are revealed in detail. Experimental results obtained with air-coupled ultrasonic transducers are well in accordance with finite element simulation results. In an experimental study, an air-coupled ultrasonic transducer is oriented at a coincidence angle such that it generates a pure fundamental antisymmetric Lamb wave mode A0 for delamination detection in laminated composite beams. The receiving transducer can be oriented either to detect the transmitted wave propagating in the same direction as incident wave or to detect the reflected wave in contrast to incident wave. The location and size of delamination can be evaluated quantitatively using the time-of-flight of reflected wave from both ends of the delamination.

Delamination damage detection of laminated composite beams using air-coupled ultrasonic transducers

Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. Numerical calculation and experimental results show that a pure Lamb wave mode can be generated if the transmitting transducer is oriented at a specific angle, and the receiving transducer can either be oriented to detect the same mode as that generated by the transmitter or to detect another mode generated by mode conversion at a defect. A three-dimensional finite element model is created to predict the interaction of Lamb waves with delamination, and some unique mechanisms of interaction between A0 mode Lamb waves and delamination are revealed in detail. The experimental results obtained on laminated composite beam using air-coupled ultrasonic transducers are well in accordance with finite element simulation results. Research results show that air-coupled ultrasonic guided waves can be used for delamination damage detection effectively in laminated composite beams.

Evaluation of Riproximin Binding Properties Reveals a Novel Mechanism for Cellular Targeting

Riproximin is a cytotoxic type II ribosome-inactivating protein showing high selectivity for tumor cell lines. Its binding to cell surface glycans is crucial for subsequent internalization and cytotoxicity. In this paper, we describe a unique mechanism of interaction and discuss its implications for the cellular targeting and cytotoxicity of riproximin. On a carbohydrate microarray, riproximin specifically bound to two types of asialo-glycans, namely to bi- and triantennary complex N-glycan structures (NA2/NA3) and to repetitive N-acetyl-D-galactosamine (GalNAc), the so-called clustered Tn antigen, a cancer-specific O-glycan on mucins. Two glycoproteins showing high riproximin binding, the NA3-presenting asialofetuin and the clustered Tn-rich asialo-bovine submaxillary mucin, were subsequently chosen as model glycoproteins to mimic the binding interactions of riproximin with the two types of glycans. ELISA analyses were used to relate the two binding specificities of riproximin to its two sugar binding sites. The ability of riproximin to cross-link the two model proteins revealed that binding of the two types of glycoconjugates occurs within different binding sites. The biological implications of these binding properties were analyzed in cellular assays. The cytotoxicity of riproximin was found to depend on its specific and concomitant interaction with the two glycoconjugates as well as on dynamic avidity effects typical for lectins binding to multivalent glycoproteins. The presence of definite, cancer-related structures on the cells to be targeted determines the therapeutic potency of riproximin. Due to its cross-linking ability, riproximin is expected to show a high degree of specificity for cells exposing both NA2/NA3 and clustered Tn structures.

Study of interaction mechanisms on zirconia‐based polystyrene HPLC column

Separation systems with a zirconia-based polystyrene HPLC column were characterized by different approaches, which allowed the recognition of interactions participating in the separation environments. Zirconia-based HPLC columns as an alternative to silica-based ones offer unique interaction mechanism based on Lewis acid-base theory. Besides hydrophobic interactions with the modified surface of the zirconia carrier it includes ion-exchange and ligand-exchange interactions that are helpful in the separation of many bioactive compounds. Three distinct approaches were applied for description of the complex separation mechanism. General chromatographic tests by Walters, Engelhardt and Galushko were applied to evaluate the fundamental properties of the systems - hydrophobicity and polarity. The complex model of linear free energy relationship described the interactions from the qualitative and quantitative points of view more in detail. Application of a set of basic compounds revealed the contribution of ion-exchange interactions participating in the separation systems.

Concise analysis of wave propagation using the spectral element method and identificationof delamination in CF/EP composite beams

This paper presents a two-dimensional spectral element method for characterizingwave propagation in composite beam structures for the purpose of damagedetection. The interaction of Lamb waves with delamination in an 8-ply carbonfiber/epoxy (CF/EP) laminate is investigated, and some unique mechanisms ofinteraction between Lamb wave modes and delamination are revealed in detail. Itis demonstrated that the reflection at the far end of the delamination is muchstronger in magnitude than that from the near end, and when the delaminationlength is comparable to the wavelength of the wave mode, the reflections fromboth ends of the delamination merge into one. The fundamental antisymmetric (A0) mode is more suitable for identification of delamination inmultilayered composite structures than the fundamental symmetric(S0) mode, especially when the delamination is in the symmetric plane. The curves of thereflection coefficient and transmission coefficient are analyzed, showing an undulatingshape, and the values of reflection or transmission coefficient are dependent on the ratio ofthe delamination length to the wavelength of the Lamb wave. A quantitative identificationmethod for delamination in composite beam structures is proposed and validated using anexperimental study.