Structural Studies Research Articles

Hawthorn (Crataegus pinnatifida) berries ripeness induced pectin diversity: A comparative study in physicochemical properties, structure, function and fresh-keeping potential

The effect of hawthorn berries ripeness on the physicochemical, structural and functional properties of hawthorn pectin (HP) and its potential in sweet cherry preservation were investigated. With the advanced ripeness of hawthorn berries, the galacturonic acid (GalA) content decreased from 59.70 mol% to 52.16 mol%, the molecular weight (Mw) reduced from 368.6 kDa to 284.3 kDa, the microstructure exhibited variable appearance from thick lamella towards porous cross-linked fragment, emulsifying activity and emulsions stability, antioxidant activities, α-amylase and pancreatic lipid inhibitory capacities significantly increased. The heated emulsion stored for 30 d presented higher creaming index and more ordered oil droplets compared to the unheated emulsion. With the extended berries ripeness, the firmness of HP gels remarkably decreased from 225.69 g to 73.39 g, while the springiness increased from 0.78 to 1.16, HP exhibited a superior inhibitory effect in water loss, browning, softening, and bacterial infection in sweet cherries preservation.

Structural Behaviour and Strength Evaluation of a Venetian Church through Finite-Element Analysis

The evaluation of the structural behaviour of a masonry Venetian church with a pointed barrel vault is presented in this paper through an analysis following the necessary steps of a monument study. With a detailed geometric model and material estimation, the finite-element method is used to investigate the influence of specific structural parts of the structure, like masonry buttresses and wall connections, on the structural behaviour. The operational modal analysis is used to identify the structure dynamically. The comparison of the eigenfrequencies, which are estimated by in situ measurements and finite-element modal analysis, is used to perform a model identification. The response spectrum analysis, the static analysis after the subsistence of some parts following strengthening proposals, and the transient analysis of specific seismic excitations are used for the evaluation of the structural behaviour. The purpose of the work is to highlight the need for an interdisciplinary approach to the study of a monumental complex structure, regardless of its scale. The coexistence of structural elements of different stiffnesses, such as vaults, elongated walls, buttresses, transverse walls with pediment and belfry, as well as the concha, affects the mechanical behaviour and the pathology of the structure, which is difficult to study with simplifying models. From the analysis, it is concluded that subsidence problems, combined with seismic actions, lead to the cracking of the masonry, while the existence of buttresses limits the extension of the damage and contributes to the stabilization of the structure.

Electronic properties prediction enhancement of 36 ternary III-IB-VI alloys using a deep feed-forward neural network

The electronic properties of 36 ternary III-IB-VI monolayers have been investigated using a correlation study, in which a comprehensive study of the band structure of these alloys is provided. To this end, a combination of density functional theory calculations and a deep feed-forward neural network is conducted. Principal component analysis and data augmentation are also implemented as pre-processing. The former reduces the size of features to mitigate redundancy, and the latter can prevent overfitting. The deep feed-forward neural network is then used for the final prediction. During the study, bandgaps of the alloys are predicted indirectly and compared with directly obtained bandgaps. The results of the predictions show a maximum precision of 0.00089 for nMSE using the deep feed-forward neural network, which confirms strong dependencies between the electronic properties of the alloys.

Effect of bonding description and strain regulation on the conductive transition of Bi semimetal

Due to the differences in the treatment methods of the electron–ion interaction and the critical strain mode of the transition from semimetals to semiconductors, the corresponding strain modulation mechanism in layered bismuth (Bi) crystals remains elusive. In this work, the effects of van der Waals (vdW) correction on the crystal structure and electrical properties of Bi in an equilibrium/strained state are comparatively studied based on the density functional theory. It is found that vdW corrections can better describe the layered crystal and bandgap structure of Bi under equilibrium/strain conditions. With the vdW modification, bismuth can be converted from a semimetal to a semiconductor within a small compression range that is experimentally available. This transition is induced by the transfer of the conduction band minimum and the valence band maximum and is related to the competition of the near-band edge energy state near the Fermi level of bismuth. The present results not only provide guidance for the accurate study of the crystal structure and electronic properties of complex model systems, such as Bi or Bi-based inherently nanostructured materials, but also reveal strain regulation mechanism of Bi and predict its potential application in the semiconductor electronic devices.

The contradiction between lithospheric thermal and seismic structures reveals a nonsteady thermal state – A case study from Northeast China

The nature of the lithosphere, as the outermost layer of the solid Earth, has long been a focus of the Earth sciences. Many methods have been used to study the properties and structure of the lithosphere, including gravity, magnetism, electricity, seismic, and geothermics. Since the 1970 s, a coupled heat-flow heat-production steady-state model has been employed to study the thermal structure of the continental lithosphere and has helped researchers explain many geothermal observations. However, the steady-state model does not work well in some areas. Taking Northeast China as a case study, we systematically calculated the lithospheric thermal structure, compared the result with seismic research, and concluded that the lithospheric thermal state is nonsteady in the southern Songliao Basin, the southern Greater Xing’an Range and the Changbai Volcano. The lithosphere in southern Songliao Basin features a hot top and a cold bottom. The lithosphere in southern Greater Xing’an Range and the Changbai Volcano feature a cold top and a hot bottom. Our numerical simulation has demonstrated that the response of surface heat flow to thermal disturbance at the bottom of the lithosphere often lags by more than 20 Myr, resulting in a significant disparity between the thermal structure calculated based on surface heat flow and the velocity structure of seismic waves. In addition, this study of the thermal structure in Northeast China shows that the temperature of the Moho in Songliao Basin is very high (>600 °C), which may be an important cause of the lack of Cenozoic volcanism in the Songliao Basin.

Sum-frequency vibrational spectroscopy, a tutorial: Applications for the study of lipid membrane structure and dynamics.

Planar supported lipid bilayers (PSLBs) are an ideal model for the study of lipid membrane structures and dynamics when using sum-frequency vibrational spectroscopy (SFVS). In this paper, we describe the construction of asymmetric PSLBs and the basic SFVS theory needed to understand and make measurements on these membranes. Several examples are presented, including the determination of phospholipid orientation and measuring phospholipid transmembrane translocation (flip-flop).

Preliminary study of the multi—physics design for the support structure of LEM—X space mission

In this modern space exploration era, the lunar site offers new opportunities such as the deployment of an X—ray observatory capable of observing half of the sky simultaneously, but also may allowing access to the entire solid angle by exploiting the rotation of the moon around its own axis.The Lunar Electromagnetic Monitor in X—rays (LEM—X) is an All Sky Monitor for the X—ray band (2–50 keV) based on the concept of coded aperture camera. The basic element is the camera of the Wide Field Monitor and the concept is to realize a ”dome” composed of N identical modules that observe different directions, thus covering an overall simultaneous field of view of 2π in the sky. In this paper, we describe the preliminary study of a support structure for that camera, the design solutions adopted for the most important thermo—mechanical drivers, which have been elaborated and used for the demonstration of compliance to the system requirements with the environment. In particular, we reported some different thermal and mechanical scenario of this preliminary structure and the optimization of critical components with innovative and accurate fem analysis.

Theoretical study of double antiaromatic structure - cyclo[16]carbon

Cyclo[16]carbon is the first antiaromatic all-carbon ring discovered in recent experiments. We studied its thermal stability and found that cyclo[16]carbon showed poor thermal stability. Subsequently, we studied its bonding properties, electron delocalization and antiaromaticity by quantum chemical calculation and wave function analysis. We observe that cyclo[16]carbon is a doubly antiaromatic system with alternating long and short bonds, where the shorter C-C bond has stronger π interactions and delocalization. In addition, by studying electron spectra and nonlinear optics, we elucidating the contribution of in-plane and out-of-plane π (πin and πout) orbitals to electron excitation, and confirming the nonlinear anisotropy of cyclo[16]carbon. Electrostatic potential (ESP) and local mean ionization energy (ALIE) analyses demonstrate the electrophilic properties of the short C-C bond. Our comprehensive characterization of cyclo[16]carbon will enable researchers to deepen their understanding of cyclo[16]carbon and thus derive its more valuable structure.

Synthesis, crystal structure, antioxidant activity and molecular docking studies of 2-(1-(3-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)ethyl)malononitrile

In the current study, we report the synthesis, structural determination, and both in vitro and in silico antioxidant assessment of 2-(1-(3-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)ethyl)malononitrile. The title compound was synthesized via the 1,4-Michael addition reaction of malononitrile with (E)-2-ethylidene-3-methyl-3,4-dihydronaphthalen-1(2H)-one in the presence of piperidine. The molecular structure of the synthesized compound was elucidated using various techniques such as 1H NMR, 13C NMR, IR, elementary analysis (AE) and confirmed by mass spectrometry (MS), as well as by the X-ray diffraction (XRD) analysis. Notably, the XRD study showed the investigated compound crystallizes in the triclinic system (S.G.: P-1). The target compound was evaluated for its antioxidant ability employing the Free radical scavenging (DPPH), Ferric reducing power (FRAP), and Phosphomolybdenum (PM) tests. The findings revealed that the compound displays an interesting antioxidant power. Furthermore, the molecular docking results show that the studied compound has a potential antioxidant effect, producing stable intermolecular interactions towards antioxidant proteins encoded in the protein data bank (PDB) by 1N8Q, 1OG5, 2CDU, and 4JK4, respectively.

Optimizing thermoelectric performance of BiSbPbTe thin films through controlled post-annealing: A comprehensive structural and electronic study

Optimizing thermoelectric performance of BiSbPbTe thin films through controlled post-annealing: A comprehensive structural and electronic study

Synthesis, photophysical, electrochemical, theoretical and self-assembly investigation of tetraphenylethene tethered arylimidazoles

To understand the comparative structure–property relationships, we have designed and synthesized 4,5-diphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole, coded as JR-1 and 4,4′-(2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole-4,5-diyl)bis(N,Ndimethylalanine)coded as JR-2. Here, we conducted various analyses, including, structural, photophysical, thermal, electrochemical, and computational studies, to gain a deeper understanding of introduction electron releasing N,N-dimethyleamine groups on later one. The molecules exhibit high thermal stability (200 − 300 °C) low band gap (2.75 – 3.26 eV) and comparable HOMO (−4.81 to − 5.35 eV) and LUMO (−2.06 to − 2.09 eV) energy levels with those of calculated and reported ambipolar materials. The UV–vis absorption was observed in the range of 300–400 nm for JR-1 and 300 − 440 nm for JR-2. These compounds exhibit distinct mechanochromism, solvatochromism, aggregation-induced emission, and aggregation-caused quenching and selective sensing. Interestingly, JR-1 exhibits mechanochromism without solvatochromism, while JR-2 is solvatochromic without mechanochromism. Due to incorporation of N,N-Dimethylphenylamine donating groups on imidazole leads to solvatochromicity and aggregation-caused quenching. Moreover, their optical properties differ significantly in dilute solutions compared to its solid state due to distinct molecular arrangements. Consequently, morphological studies reveal the formation of 3D rod and spear-shaped s supramolecular self-assembly structures in different solvent mixtures. This research work offers a fundamental strategy for the design of fluorophores for optoelectronic applications.

Structural, Microstructural, and Electrical Properties Study of Pb(Sn0.45Ti0.55)O3 Ceramics

We undertook a comprehensive investigation of the the structural, dielectric, and electrical characteristics of Pb(Sn0.45Ti0.55)O3 ceramics prepared using the conventional solid-state route. A meticulous preparation protocol, involving solvating various precursors, was followed by extensive characterization employing X-ray diffraction, scanning electron microscopy, and dielectric studies. The synthesized sample features a single-phase tetragonal structure with P4mm symmetry. Using impedance spectroscopy, electrical transport properties of the polycrystalline Pb(Sn0.45Ti0.55)O3(PST) ceramic were studied in detail. Relaxation and conduction mechanisms of the material were inferred using complex impedance, complex electric modulus, and frequency dependent ac conductivity analysis. Impedance spectroscopy results reveal the range of frequencies in which the grain, grain boundary, and electrode effects are dominant. Above certain temperatures, the imaginary component of impedance (Z//) exhibits some resonant type peaks at different frequencies indicating relaxor nature of the sample. The activation energy obtained for both the relaxation and conduction process indicates the role of doubly-ionized oxygen vacancy in the conduction mechanism of the sample. The dielectric relaxation occurring at low frequency and high temperatures is related to the space charges associated with the ionized oxygen vacancies being trapped at the grain boundaries. The Cole-Cole plots confirm the poly-dispersive nature of dielectric relaxation in the sample.

Identification and characterization of a chondroitinase ABC with a novel carbohydrate-binding module

Chondroitinases play important roles in structural and functional studies of chondroitin sulfates. Carbohydrate-binding module (CBM) is generally considered as an accessory module in carbohydrate-active enzymes, which promotes the association of the appended enzyme with the substrate and potentiates the catalytic activity. However, the role of natural CBM in chondroitinases has not been investigated. Herein, a novel chondroitinase ChABC29So containing an unknown domain with a predicted β-sandwich fold was discovered from Segatella oris. Recombinant ChABC29So showed enzyme activity towards chondroitin sulfates and hyaluronic acid and acted in a random endo-acting manner. The unknown domain exhibited a chondroitin sulfate-binding capacity and was identified as a CBM. Biochemical characterization of ChABC29So and the CBM-truncated enzyme revealed that the CBM enhances the catalytic activity, thermostability, and disaccharide proportion in the final enzymatic products of ChABC29So. These findings first demonstrate the role of the natural CBM in a chondroitinase and will guide future modification of chondroitinases.

Cu1.3Mn1.7O4/LaNi0.6Fe0.4O3 composite with prospects for IT-SOFC/SOEC applications

Composite materials with the composition (100-x)Cu1.3Mn1.7O4/xLaNi0.6Fe0.4O3 (CMxLNF, where: x= 5, 10, 15, 20, 30, 40 and 50wt%) were evaluated as possible coating materials for SOFC/SOEC metallic interconnects. The introduction of LaNi0.6Fe0.4O3 into spinel matrices improved electrical conductivity compared to pure Cu1.3Mn1.7O4. The measured Seebeck coefficient values indicate that carrier concentration increased with LaNi0.6Fe0.4O3 content, yet the activation energy of the carriers' mobility decreased. Extensive structural and microstructural studies of selected CM/LNF systems showed that composite material components exhibited high stability in relation to one another. Additionally, LaNi0.6Fe0.4O3 significantly improved the chemical stability of Cu1.3Mn1.7O4 in the presence of chromia, as tested after 150h of exposure to air at 800 °C. Finally, coatings based on selected composite powders were deposited electrophoretically on the steel and were oxidized for 1500h in air at 750 °C, confirming that CM10LNF can be applied as effective protective-conducting coatings on low-chromium ferritic steel.

Inclusion complex of trans-p-coumaroyl-secologanoside (comselogoside) with β-cyclodextrin. Part I. structural characterization and study of solubilization and stabilization.

Comselogoside (COM) is a secoiridoid, derivative of p-coumaric acid with a wide range of potential beneficial properties, although its poor aqueous solubility and low stability limit its study and application. The formation of an inclusion complex with β-cyclodextrin (β-CD) could improve the solubility and photostability of COM. The complexation of COM with β-CD in an aqueous solution has been studied for the first time, using the freeze-drying method with high encapsulation yield and efficiency. The formation of the inclusion complex was confirmed by electrospray ionization (ESI) mass and 1H NMR spectroscopy. Phase solubility studies provided an AN-type diagram with an increase in aqueous solubility by 100% and the formation of a high stoichiometric order complex COM: β-CD. The 1H NMR analysis with different COM/β-CD molar ratio established the formation of the 2:1 stoichiometric complex by Job ҆ s plot. In addition, the complexation of COM with β-CD improved the stability of COM against irradiation with UV light at 254 nm. Finally, combined docking and DFT calculations have been performed to study the formation and interactions of the COM: β-CD complexes. The computational results show excellent agreement with experimental observations.

Design, Synthesis, DFT, docking Studies, and antimicrobial evaluation of novel benzimidazole containing sulphonamide derivatives

In silico approaches have been employed to design a new series of benzimidazole-containing sulphonamide derivatives and qualified compounds have been synthesized to analyze their potential as antimicrobial agents. Antibacterial screening of all synthesized compounds was done using the broth microdilution method against several human pathogenic bacteria, viz. Gram-positive bacteria [B. cerus (NCIN-2156), B. subtilis (ATCC-6051), S. aureus (NCIM-2079)] and Gram-negative bacteria [P. aeruginosa (NCIM-2036), E. coli (NCIM-2065), and a drug-resistant strain of E. coli (U-621)], and the compounds presented admirable MIC values, ranging between 100–1.56 µg/mL. The combinatorial analysis showed the magnificent inhibitory efficiency of the tested compounds, acquired equipotent to ten-fold more potency compared to original MIC values. An immense synergistic effect was exhibited by the compounds during combination studies with reference drugs chloramphenicol and sulfamethoxazole was presented as fractional inhibitory concentration (∑FIC). Enzyme inhibition studies of all synthesized compounds were done by using peptidyl transferase and dihydropteroate synthase enzymes isolated from E. coli and S. aureus and each of the compound presented the admirable IC50 values, where the lead compound 3 bound to peptidyl transferase (of S. aureus with IC50 363.51 ± 2.54 µM and E. coli IC50 1.04 ± 0.08 µM) & dihydropteroate synthase (of S. aureus IC50 3.51 ± 0.82 µM and E. coli IC50 2.77 ± 0.65 µM), might account for the antimicrobial effect, exhibited excellent inhibition potential. Antifungal screening was also performed employing food poisoning methods against several pathogenic fungal species, viz A. flavus, F. oxysporum, A. niger, and A. brassicae. The obtained result indicated that few compounds can prove to be a potent drug regimen against dreaded MDR strains of microbes. Structural activity relationship (SAR) analysis and docking studies reveal that the presence of electron-withdrawing, polar, and more lipophilic substituents positively favor the antibacterial activity, whereas, electron-withdrawing, more polar, and hydrophilic substituents favor the antifungal activities. A robust coherence has been found in in-silico and in-vitro biological screening results of the compounds.

Structural, optical, thermal, and dielectric studies of urea-doped potassium hydrogen phthalate single crystals: effect of Ocimum Tenuiflorum extract

Structural, optical, thermal, and dielectric studies of urea-doped potassium hydrogen phthalate single crystals: effect of Ocimum Tenuiflorum extract

Cloning, expression and purification of cellobiohydrolase gene from Caldicellulosiruptor bescii for efficient saccharification of plant biomass

Anthropogenic activities have led to a drastic shift from natural fuels to alternative renewable energy reserves that demand heat-stable cellulases. Cellobiohydrolase is an indispensable member of cellulases that play a critical role in the degradation of cellulosic biomass. This article details the process of cloning the cellobiohydrolase gene from the thermophilic bacterium Caldicellulosiruptor bescii and expressing it in Escherichia coli (BL21) CondonPlus DE3-(RIPL) using the pET-21a(+) expression vector. Multi-alignments and structural modelling studies reveal that recombinant CbCBH contained a conserved cellulose binding domain III. The enzyme's catalytic site included Asp-372 and Glu-620, which are either involved in substrate or metal binding. The purified CbCBH, with a molecular weight of 91.8 kDa, displayed peak activity against pNPC (167.93 U/mg) at 65 °C and pH 6.0. Moreover, it demonstrated remarkable stability across a broad temperature range (60–80 °C) for 8 h. Additionally, the Plackett-Burman experimental model was employed to assess the saccharification of pretreated sugarcane bagasse with CbCBH, aiming to evaluate the cultivation conditions. The optimized parameters, including a pH of 6.0, a temperature of 55 °C, a 24-hour incubation period, a substrate concentration of 1.5 % (w/v), and enzyme activity of 120 U, resulted in an observed saccharification efficiency of 28.45 %. This discovery indicates that the recombinant CbCBH holds promising potential for biofuel sector.

Structural, Morphological, Optical, and Magnetic Properties of NiO-added NiCo2O4 Electrode Materials Synthesized by Sol-Gel, Co-Precipitation and Ultrasonication Methods and their Electrochemical Supercapacitor Response

In this study, NiO-added NiCo2O4 composite samples were prepared using three distinct synthesis methods to study the impact of synthesis technique and NiO addition on the electrochemical performance of NiCo2O4. The chosen methods, sol-gel, co-precipitation, and ultrasonication, represent a range of approaches that yield different particle structures and morphologies. The structural and morphological studies of composite samples were investigated using X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM), respectively. XRD analysis revealed the crystalline composition, revealing the presence of two distinct phases: NiO and NiCo2O4. The Rietveld analysis of the composite samples supports the dual phases in the samples. FESEM analysis confirms the change in size and shape of the particles with the synthesis procedure. Optical properties, measured via UV-visible absorbance spectra, demonstrated that the energy gap varied with the synthesis method. The sol-gel samples exhibited the highest energy gap at 2.20 eV. The magnetic properties were measured using the vibration sample magnetometer (VSM), and the results confirm that the synthesis procedure influences magnetic loops and coercivity. The electrochemical performance of the samples in a 3 M potassium hydroxide electrolyte revealed that the co-precipitation method produced the highest capacitance of 398 Fg-1 at a 10 mV/s sweep rate, indicating superior energy storage capacity compared to pure NiCo2O4. Adding NiO phase to the NiCo2O4 matrix is believed to enhance electrochemical performance by creating additional charge at the grain boundaries, leading to a synergistic effect and improved electron and ion transport. The exceptional electrochemical performance of these composite materials suggests that the synthesis methods and the addition of NiO play a critical role in determining the overall efficiency and applicability of battery-type supercapacitors. These findings pave the way for further research into optimizing synthesis parameters to enhance energy storage capacity and inspire the development of advanced spinel metal oxide composite electrodes for supercapacitors and other energy storage applications.

A thin-skinned thrust model for ice-marginal glacitectonic detachment and emplacement of Carboniferous bedrock rafts at Kilcummin Head, NW Ireland

This paper presents the results of a detailed macro- and microscale structural study of the glacitectonised sequence at Kilcummin Head on the western side of Killala Bay, County Mayo, northwest Ireland. The sequence comprises two laterally extensive, thrust-stacked rafts of Carboniferous limestone and mudstone emplaced upon the in situ bedrock of the Ballina Limestone Formation. Restored cross-sections reveal that the glacitectonised sequence has undergone extensive deformation and shortening of 61 %. This accompanied the formation of a prominent thrust-moraine associated with a northward ice advance across Killala Bay during the Midlandian (Devensian). A five-stage model is proposed to describe the deformation. Stage 1 comprises detachment of the rafts, and the majority of the sequence shortening. North-directed transport of the rafts occurred on a major décollement surface located at the base of the rafted sequence, marked by a mudstone-rich glacitectonite. Stage 2 accommodated further shortening via a series of imbricate thrusts leading to the stacking of the bedrock rafts (Stages 3 and 4). Stage 5 saw final stacking of rafts within a prominent thrust-block moraine, followed by the deposition of a sequence of coarse-grained, ice-marginal glacigenic deposits.