Inherent Structural Characteristics Research Articles

One-step selective dehydrogenation of cyclic hemiacetal sugars toward to their chiral lactones

Chiral glycosyl lactone is an important class of bioactive compound and pharmaceutical intermediate in nature, especially for chiral lactones with 4 carbon atoms, which are very useful building blocks for synthesis of biologically interesting compounds. Herein, a selective dehydrogenation and solvent matched catalytic system under oxygen-free conditions was developed to try to achieve the one-step direct conversion of cyclic hemiacetal sugars toward their chiral glycosyl lactones. During the process, the inherent structural characteristics of sugar was efficiently utilized, and the transfer of its chiral centers was realized. Under the optimum condition, the corresponding lactones were successfully prepared from C4-C6 sugars with cyclic hemiacetal structure in acetonitrile. The reaction mechanism in acetonitrile was explored by the first principle density functional theory calculations and tracking reaction process. It was found that the high lactone yield in acetonitrile was due to the high proportion of α-conformation form among multiple tautomers in it. This selective dehydrogenation process may further extend the possibility of the preparation of chiral synthons from carbohydrates directly.

Facile Synthesis of Energetic Nanoparticles of Copper Azide with High Initiation Ability for Micro-Initiator Applications Using Layered Copper Hydroxide.

Copper azide (CA) is one of the preferred primary explosives in the micro-initiating device, and it is of conducive significance to develop high-content CA-modified materials. In this work, we reported two types of CA composites with CA nanorods embedded in carbon nanosheets (CA/C) and CA distributed on salicylic acid (CA/SA) using layered copper hydroxide nanosheets intercalated with salicylic acid as the precursor. The detailed characterizations demonstrated that CA/C exhibits eximious electrostatic sensitivity (1.06 mJ) due to the inherent structural characteristics of CA/C such as the limitation of the free movement of CA by the layered structure and preeminent electrical conductivity of carbon nanosheets. Surprisingly, CA/C with nearly 1.0 mg in the miro-initiating device can reliably detonate Hexanitrohexaazaisowurtzitane (CL-20). CA/C exhibits extremely high CA content (93%), excellent ignition ability, and detonation ability, and its performance is superior to pure CA and most CA-modified materials reported previously. CA/SA also has an excellent detonation ability and its electrostatic sensitivity is as low as 0.92 mJ. These findings provide a new perspective for the development of high-performance primary explosives for the micro-initiating device.

Optimizing energy consumption structure in Chongqing of China to achieve low-carbon and sustainable development based on compositional data

The optimal allocation of energy consumption structure has a vital impact on the sustainable development of economy and environment. However, the joint prediction and systematic analysis of the overall energy consumption structure are faced with great challenges due to its inherent structural characteristics. In this paper, an energy consumption structure prediction method based on dimension reduction through hyperspherical transformation and composite quantile regression neural network (DRHT-CQRNN) for compositional data is innovatively developed, which can reveal the relative information behind the absolute value of energy consumption. On this basis, the energy consumption structure of Chongqing of China during the 14th Five-Year Plan period (2021–2025) is predicted, and relevant policy recommendations are proposed to promote the transformation of the energy consumption structure of Chongqing. The research results show that by 2025, the consumption structure of coal, natural gas, petroleum and others will be 45.53%, 21.79%, 21.44% and 11.23%, respectively. The proportion of coal consumption in Chongqing will continue to decline, while the share of low-carbon, high-efficiency, high-quality energy will gradually increase. This paper demonstrates the excellent performance of the compositional data combination prediction model in terms of energy structure, which is also important for the formulation of energy structure policy in Chongqing.

Nanochitin: Chemistry, Structure, Assembly, and Applications.

Chitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability to structure into hierarchical assemblies, spanning the nano- and macroscales, imparting toughness and resistance (chemical, biological, among others) to multicomponent materials as well as adding adaptability, tunability, and versatility. Retaining the inherent structural characteristics of chitin and its colloidal features in dispersed media has been central to its use, considering it as a building block for the construction of emerging materials. Top-down chitin designs have been reported and differentiate from the traditional molecular-level, bottom-up synthesis and assembly for material development. Such topics are the focus of this Review, which also covers the origins and biological characteristics of chitin and their influence on the morphological and physical-chemical properties. We discuss recent achievements in the isolation, deconstruction, and fractionation of chitin nanostructures of varying axial aspects (nanofibrils and nanorods) along with methods for their modification and assembly into functional materials. We highlight the role of nanochitin in its native architecture and as a component of materials subjected to multiscale interactions, leading to highly dynamic and functional structures. We introduce the most recent advances in the applications of nanochitin-derived materials and industrialization efforts, following green manufacturing principles. Finally, we offer a critical perspective about the adoption of nanochitin in the context of advanced, sustainable materials.

Improving the Long‐Term Stability of BPQD‐Based Memory Device via Modification with Polyvinylpyrrolidone‐Grafted Polydopamine

AbstractLong‐term environmental stability of electronic and optoelectronic devices is a very important concern. Both black phosphorus (BP) nanosheets and quantum dots (BPQDs) exhibit very poor environmental stability. To address this problem, a new encapsulation approach for improving long‐term stability of the BPQD‐based electronic devices, which concerns two‐step in situ polymerizations: 1) in situ polymerization of dopamine in the presence of BPQDs giving a BPQDs@PDA (PDA: polydopamine) composite; 2) in situ atom transfer radical polymerization of N‐vinyl‐2‐pyrrolidone on the BPQDs@PDA surface producing the BPQDs@PDA–PVP composite (PVP: polyvinylpyrrolidone), is developed. Both the Al/BPQDs@PDA–PVP/ITO and Al/BPQDs:PVP blends/ITO devices show excellent nonvolatile memory performance at the initial measurement stage. Interestingly, the former can only be programmed to the high conductivity state in the positive bias range, while the latter can be switched into the ON state only in the negative bias range. The different switching directions may be highly associated with the inherent electronic structural characteristics of the materials. In contrast to the BPQDs:PVP blends and/or BPQDS@PDA:PVP blend‐based electronic devices with very unstable memory performance, the memory performance of the BPQDs@PDA–PVP‐based device remains unchanged even standing for 90 d.

Oxygen vacancy migration and its lattice structural origin in A-site non-stoichiometric bismuth sodium titanate perovskites

Off-stoichiometry of perovskite structural Bi0.5Na0.5TiO3 (BNT) ferroelectrics can give rise to considerable oxide-ion conductivity. The inherent structural characteristics are urgent to be resolved due to its particular sensitivity of the conduction mechanism to the nominal composition and synthesis process. Herein, a thorough study of the temperature-dependent neutron, X-ray diffraction and Raman spectrum is carried out on a series of equivalently substituted A-site deficient non-stoichiometric and pristine BNT. Phase transition and defect association are systemically investigated in these dominated rhombohedral phases at room temperature, associated with well saturated ferroelectric states. Significant structural evolution identified by Rietveld refinements and the origin of the electrical performance are clarified at elevated temperatures, focusing on the subtle distortions of ionic displacements, oxygen octahedral tilts and local chemical environments for oxygen vacancies. The ion migration ability mediated by oxygen vacancies that are not energetically favorable in BNT mainly depends on the external substitutional disorder, and is strongly affected by the dopant concentration. Together with the lone pair substitution concept, superior oxide ionic conductivity is achieved, and an alternative strategy is provided in designing BNT based oxide ion conductors.

A novel load-dependent sensor placement method for model updating based on time-dependent reliability optimization considering multi-source uncertainties

An effective sensor network with an appropriate sensor configuration is the first step of model updating to obtain the actual structural response. However, sensor placements based on inherent structural characteristics (such as mode shapes) alone or their optimizations only with deterministic data are unlikely to provide very good results. Therefore, using a non-probabilistic theory to characterize the uncertainty in the uncertainty propagation process for model updating, this study proposes a time-dependent, reliability-based method for the optimal load-dependent sensor placement considering multi-source uncertainties. Due to the limitations of the uncertain parameters obtained using probabilistic or statistical methods, the uncertainties tackled in this study that includes those from structural properties and measurement processes are regarded as interval variables. Using the first-passage theory in the overall time history, different crossing situations of the reduced time history responses (that is, the modal coordinates) with respect to the full ones are constructed. The difference between the modal coordinates of the reduced and the full models is defined as the objective of the optimization, which indicates the matching level. Based on the time-dependent reliability-based index and the errors of deterministic modal coordinates between the reduced and full models, the multi-objective optimization is solved using NSGA-II. A detailed flowchart of the proposed method is given, and its effectiveness is verified by two simulated engineering examples for model updating.

MXene-based designer nanomaterials and their exploitation to mitigate hazardous pollutants from environmental matrices

MXenes are a rapidly expanding and large family of two-dimensional (2D) materials that have recently garnered incredible research interests for diverse applications domains in various industrial sectors. Owing to unique inherent structural and physicochemical characteristics, such as high surface area, biological compatibility, robust electrochemistry, and high hydrophilicity, MXenes are appraised as a prospective avenue for environmental-clean-up technologies to detect and mitigate an array of recalcitrant hazardous contaminants from environmental matrices. MXene-based nanoarchitectures are thought to mitigate inorganic pollutants via interfacial chemical transformation and sorption, while three different mechanisms, including i) surface complexation and sorption (ii) catalytic activation and removal and (iii) radical's generation-based photocatalytic degradation, are involved in the removal of organic contaminants. Considering the application performance of MXenes on the incessant rise to expansion, in this review, we discuss the wide-spectrum applicability of diverse MXenes-based hybrid nanocomposites in environmental remediation. A brief description related to environmental pollutants, structural properties, chemical abilities, and synthesis route of MXenes is delineated at the start. Afterwards, the adsorption and degradative robustness of MXene-based designer nanomaterials for various contaminants including organic dyes, toxic heavy metals, pesticide residues, phenolics, antibiotics, radionuclides, and many others are thoroughly vetted to prove their potentiality in the arena of wastewater purification and remediation. Lastly, challenges and trends in assessing the wide-range applicability and scalability of MXenes are outlined. Seeing encouraging outcomes in plenty of reports, it can be concluded that MXenes-based nanostructures could be considered the next-generation candidates for water sustainability.

When Albumin Meets Liposomes: A Feasible Drug Carrier for Biomedical Applications.

Albumin, the most abundant protein in plasma, possesses some inherent beneficial structural and physiological characteristics that make it suitable for use as a drug delivery agent, such as an extraordinary drug-binding capacity and long blood retention, with a high biocompatibility. The use of these characteristics as a nanoparticle drug delivery system (DDS) offers several advantages, including a longer circulation time, lower toxicity, and more significant drug loading. To date, many innovative liposome preparations have been developed in which albumin is involved as a DDS. These novel albumin-containing liposome preparations show superior deliverability for genes, hydrophilic/hydrophobic substances and proteins/peptides to the targeting area compared to original liposomes by virtue of their high biocompatibility, stability, effective loading content, and the capacity for targeting. This review summarizes the current status of albumin applications in liposome-based DDS, focusing on albumin-coated liposomes and albumin-encapsulated liposomes as a DDS carrier for potential medical applications.

Exploration of biodegradation traits in dairy cows and protein spectroscopic features in microwaved and moist heated tannin and non-tannin Faba bean

The objective of this study was to explore if microwave irradiation and moist autoclaving treatments could change nutritive values, nutrients availability and protein inherent spectral structural characteristics in tannin (var. Fatima) and non-tannin (var. Snowbird) faba beans. An in situ approach with four cannulated dry Holstein dairy cows was applied in this study. The results showed that beans heated with microwave and autoclaving had increased contents of ether extract and neutral detergent insoluble CP and reduced soluble CP, sugar and tannin concentrations when compared with the raw seeds. Heating reduced degradable nutrients in the rumen and increased intestinally absorbable nutrients, but it failed to improve digestibility in total tract. All the results showed heating with moisture and pressure would be stronger and severer than microwave irradiation. The variety of faba bean interacted with thermal treatment on total truly intestinally absorbed protein value which showed to be highest in the microwaved brown faba bean and lowest in the unheated Snowbird bean. The degraded protein balance (OEB) value was significantly decreased after both kinds of heating process, suggesting that heating treatments could mitigate loss of nitrogen from the rumen to a large extent. We further collected spectral data using mid-IR spectroscopy and found heat processed beans had varied peak height and area ratios compared with raw beans. However, multivariate results implied that heating process failed to completely change the whole molecular conformation in the protein amide region. Correlations were found between ADF/ADL and spectral features, and the OEB value was negatively related to protein secondary structural α-helix. In conclusion, both faba beans were more sensitive to autoclaving treatment than microwave irradiation in terms of nutrient availability in ruminants.

High resolution NDT in the characterization of the inner structure and materials of heritage buildings walls and columns

Rehabilitation, restoration and maintenance of monuments, heritage and buildings pose challenging tasks to engineers and architects, as any intervention must respect their architectural and constructive characteristics. Often these are unknown and sources of information have long been lost in time. Thus, there is a need to use methods capable of providing information on a wide range of aspects such as building foundations, construction characteristics and materials, alterations from the original layout, infrastructure mapping, pathologies, etc. These methods must respect the inherent structural delicacy and characteristics of ancient buildings and non-destructive methods, NDT such as geophysical methods, have been proposed to investigate these problems.It is common knowledge that a single geophysical method cannot provide full information on the problems to investigate. Thus, herein the combined use of Seismic Transmission Tomography and Ground Penetrating Radar – GPR - is demonstrated to provide important results in the investigation of the constructive elements (columns and walls) of a 14th century UNESCO monument. As demonstrated, high-resolution geophysical data obtained from both methods provide very good images of the interior of both walls and columns giving information on the quality and spatial distribution of the materials used in the construction of the monument.Finally, the results herein discussed prove the suitability and complementarity of these two methods to investigate, built heritage, monuments and buildings in general.

Novel Use of Ultra-Resolution Synchrotron Vibrational Micropectroscopy (SR-FT/vIMS) to Assess Carinata and Canola oilseed tissues within Cellular and Subcellular Dimensions.

The study was conducted to: (1) apply advanced synchrotron radiation-based technique-SR-FT/vIMS to detect chemical profiles that are related to protein and carbohydrate biopolymers, (2) quantify the relationship between spectral features and nutrient utilization and bioavailability of newly developed carinata and canola seed lines. The molecular spectral features of these seed lines were analyzed using SR-FT/vIMS with both univariate and multivariate spectral analysis techniques. The results showed that the inherent structural characteristics of new carinata and new canola seeds could be detected by SR-FT/vIMS. The univariate molecular spectral analysis showed differences in absorption intensities (peak heights and areas) of functional groups related to protein and carbohydrate molecular structures, while multivariate molecular spectral analysis without any spectral parameterization results showed similar protein and carbohydrate structure between new carinata and new canola seeds. Based on both, univariate and multivariate analysis, there were some differences between carinata seeds and canola seeds in protein and Carbohydrate (CHO) structure spectral characteristics, but these differences were not distinguishable in CLA and PCA plots regardless the color seed coat when using original spectral without spectral parameterization. Protein and carbohydrate structural variables could be used as predictors of rumen protein degradation kinetics, protein intestinal digestion features and protein supply for dairy cows. The CHO molecular structure showed great correlation with rumen protein degradation, intestinal protein digestion and predicted true protein supply of the newly developed carinata and canola lines.

Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS2 and Its Potential for Enhancement of Tribological Properties.

Two-dimensional transition-metal dichalcogenides possess inherent structural characteristics that can be harnessed for enhancement of tribological properties by making them dispersible in lube media. Here, we present a hydrothermal approach to preparing MoS2 nanosheets comprising 4-10 molecular lamellae. A structural-defect-mediated route for grafting of octadecylamine (ODA) on MoS2 nanosheets is outlined. The unsaturated d orbitals of Mo at the sulfur vacancies on the MoS2 surface are coupled with the electron-rich nitrogen center of ODA and yield ODA-functionalized MoS2 (MoS2-ODA). The MoS2-ODA nanosheets exhibit good dispersibility in lube base oil and are used as an additive (optimized dose: 0.1 mg·mL-1) to mineral oil. It is shown that even at low concentration, MoS2-ODA nanosheets significantly reduce the friction (48%) and wear (44%). Microscopy (field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM)) and spectroscopy (Raman and elemental mapping) analyses of worn scars revealed the formation of MoS2-based protective thin films for lowering of friction and wear. This work, therefore, presents a pathway for low-friction lubricants by deploying functionalized low-dimensional material systems.

In-House Standard Method for Molecular Characterization of Dissolved Organic Matter by FT-ICR Mass Spectrometry.

Electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been widely used for molecular characterization of dissolved organic matter (DOM). However, ESI FT-ICR MS generally has poor repeatability and reproducibility because of its inherent ionization mechanism and structural characteristics, which severely hindered its application in quantitative analysis of complex mixtures. In this article, we developed an in-house standard method for molecular characterization of DOM by ESI FT-ICR MS. Instead of obtaining reproducible results by determining the instrument parameters, we adopted an approach of object control on the mass spectrum to solve the problem of poor reproducibility. The mass peak shape, resolution, and relative intensity distribution of a natural organic matter standard were adjusted by optimizing the operating conditions to obtain a repeatable result. The quality control sample was run 26 times by the different operators in a 6-month-long period to evaluate the reproducibility. Results showed that the relative standard deviation (%) of repeatability and reproducibility are 1.02 and 2.35 for average H/C, respectively. The in-house standard method has been validated and successfully used for the characterization of more than 4000 DOM samples, which is transferable to other laboratories.

Universal three-dimensional crosslinker for all-photopatterned electronics

All-solution processing of large-area organic electronics requires multiple steps of patterning and stacking of various device components. Here, we report the fabrication of highly integrated arrays of polymer thin-film transistors and logic gates entirely through a series of solution processes. The fabrication is done using a three-dimensional crosslinker in tetrahedral geometry containing four photocrosslinkable azide moieties, referred to as 4Bx. 4Bx can be mixed with a variety of solution-processable electronic materials (polymer semiconductors, polymer insulators, and metal nanoparticles) and generate crosslinked network under exposure to UV. Fully crosslinked network film can be formed even at an unprecedentedly small loading, which enables preserving the inherent electrical and structural characteristics of host material. Because the crosslinked electronic component layers are strongly resistant to chemical solvents, micropatterning the layers at high resolution as well as stacking the layers on top of each other by series of solution processing steps is possible.

What does fluorine do to a protein? Thermodynamic, and highly-resolved structural insights into fluorine-labelled variants of the cold shock protein

Fluorine labelling represents one promising approach to study proteins in their native environment due to efficient suppressing of background signals. Here, we systematically probe inherent thermodynamic and structural characteristics of the Cold shock protein B from Bacillus subtilis (BsCspB) upon fluorine labelling. A sophisticated combination of fluorescence and NMR experiments has been applied to elucidate potential perturbations due to insertion of fluorine into the protein. We show that single fluorine labelling of phenylalanine or tryptophan residues has neither significant impact on thermodynamic stability nor on folding kinetics compared to wild type BsCspB. Structure determination of fluorinated phenylalanine and tryptophan labelled BsCspB using X-ray crystallography reveals no displacements even for the orientation of fluorinated aromatic side chains in comparison to wild type BsCspB. Hence we propose that single fluorinated phenylalanine and tryptophan residues used for protein labelling may serve as ideal probes to reliably characterize inherent features of proteins that are present in a highly biological context like the cell.

Strong acid- and solvent-resistant polyether ether ketone separation membranes with adjustable pores

Polyether ether ketone (PEEK) is composed of repeating phenyl ether and benzophenone units and exhibits strong chemical resistance in harsh solvents due to their inherent structural characteristics. In view of its stability and un-processability, the traditional methods of preparing membranes limited further application. In this work, we proposed a facile route toward the preparation of PEEK membranes via traditional non-solvent-induced phase separation (NIPS) and a facile one-step heat treatment for the first time to the best of our knowledge. Most intriguingly, the morphologies, pore size, water permeability and selectivity of PEEK membranes could be simply modified by heat treatment. The effect of the pore size on permeability and selectivity was investigated for bovine serum albumin (BSA, 66.4 K Da), rose bengal sodium salt (RB, 1017 Da) and methyl blue (MB, 799 Da). Aside from a high selectivity (rejection higher than 90% for different molecular structures) being obtained, the membranes showed excellent reproducibility in organic solvents and strong acid. Moreover, the separation performance remained unchanged in a long-term operation. The application of this simple and highly economical method expands the research direction of PEEK membranes and promotes the further application in separation and purification.

Effects of Inherent Structural Characteristics on Seismic Performances of Aseismically Base-Isolated Buildings

Effects of inherent characteristics of both isolation system (IS) and superstructure on seismic performances of aseismically base-isolated buildings subjected to near- and far-field ground motions are investigated through extensive numerical analyses. ISs considered are friction pendulum system (FPS) and high-damping laminated rubber bearing (HRB), as the most practical ISs. Superstructures are 3-, 7-, and 11-story buildings with steel and reinforced concrete moment-resisting and braced frames. Seven isolation strategies are practically designed by the ISs, using three target displacements and two coefficients of friction. Eighty-four structural models are created for the 12 superstructures isolated by the two ISs. 1176 nonlinear time history analyses are carried out on the two-dimensional models of the isolated buildings subjected to seven near-field and seven far-field ground motions. Base shears, story displacements, and story accelerations are studied as the performance criteria. It is shown that the effectiveness of aseismic base isolation depends significantly on inherent mass, stiffness, and damping of the structure. The effect of isolation damping is more than mass and stiffness of the superstructure. The effectiveness of aseismic base isolation with the design strategies controlled by target displacement increases by increase in the inherent mass and stiffness of the superstructure, while facing reduction due to inherent increase in the isolation damping. The effects are similar in near- and far-field ground motions. Seismic performances of FPS are less sensitive to the effects of inherent structural characteristics. With the conditions and parameters set in this study, it is found that FPS performs better than HRB, specifically in near-field excitations.

Interactive association between processing induced molecular structure changes and nutrient delivery on a molecular basis, revealed by cutting-edge vibrational biomolecular spectroscopy

BackgroundThis study was conducted to determine protein molecular structure profiles and quantify the relationship between protein structural features and protein metabolism and bioavailability of blend pelleted products (BPP) based on co-products (canola or carinata) from processing with different proportions of pulse pea screenings and lignosulfonate chemical compound.MethodThe protein molecular structures were determined using the non-invasive advanced vibrational molecular spectroscopy (ATR-FT/IR) in terms of chemical structure and biofunctional groups of amides (I and II), α-helix and β-sheet.ResultsThe results showed that increasing the level of the co-products in BPP significantly increased the spectral intensity of the amide area and amide height. The products exhibited similar protein secondary α-helix to β-sheet ratio. The protein molecular structure profiles (amides I and II, α-helix to β-sheet) were highly associated with protein degradation kinetics and intestinal digestion. In conclusion, the non-invasive vibrational molecular spectroscopy (ATR-FT/IR) could be used to detect inherent structural make-up characteristics in BPP.ConclusionThe molecular structural features related to protein biopolymer were highly associated with protein utilization and metabolism.

Composition related structural transition between mechanosynthesized CsPbBr3 and CsPb2Br5 perovskites and their optical properties

A facile solvent-free mechanochemical synthesis mechanism of perovskites of Cs–Pb–Br system has been demonstrated in the present study. Inherent structural and microstructural characteristics of CsPbBr3 and CsPb2Br5 perovskites are investigated by analyzing powder XRD patterns using Rietveld refinement analysis and formation of these perovskites has been ascertained. The compositional phase transition between orthorhombic CsPbBr3 and tetragonal CsPb2Br5 perovskites has been explained from the structural point of view. The optically active orthorhombic CsPbBr3 perovskite transforms to optically inactive tetragonal CsPb2Br5 perovskite under flowing water vapour within a short duration and the reverse transformation is noticed when the tetragonal perovskite is heat-treated at elevated temperature. Optical properties of these perovskites corroborate well with structural phase transitions of these compounds. This new approach of structural conversion not only provides a controlled synthesis of the ternary Cs–Pb–Br system but also demonstrates a clear underlying mechanism for the structural instability and associated optical properties.