Structural Change Research Articles

Pair Distribution Function Analysis of Local Structural Rearrangement in Spinel Vanadium Oxide Cathodes

Being a divalent cation with the lowest mass, Mg2+ has garnered quite attention in recent times due to the high volumetric capacity of it’s batteries. Theoretical studies reveal that the combination of a Mg anode and a spinel oxide cathode would be able to surpass the current limits found in widely used Li-ion batteries Therefore, to design materials with high diffusion and reversible insertion capacity, a conclusive demonstration of the intercalation mechanism of Mg2+ into metal oxides, is required.Among the numerous options for cathodes, vanadium oxides show evidence of the largest capability toward reversible intercalation of Mg ions. In particular, spinel-type MgV2O4 shows a capacity of 200 mAh/g, corresponding to the cycling of ~0.7 mol Mg2+ per mol of oxide, and layered α-V2O5 reaches 300 mAhg-1, intercalating 1 mol Mg2+ per mol of oxide. The extent and reversibility of these reactions were confirmed by elemental, redox and structural characterization in recent work [1,2]. This high capacity is only observed at 110°C and it is accompanied by a large hysteresis in potential during the electrochemical cycling. The push to overcome these bottlenecks demands a more comprehensive definition of the underlying mechanisms of reaction than is currently available.Previous X-ray Diffraction (XRD) measurements conducted on the oxide indicated a loss of reflection intensity due to a loss in their crystallinity which makes structural characterization using typical diffraction techniques difficult. Through this work, we mainly make use of pair distribution function techniques to study the changes in the local structures of these oxides in both their pristine and charged state, and the effect of annealing for longer hours with the goal of further pushing the efficiency of multivalent battery materials.Reference: Hu, L., Jokisaari, J.R., Kwon, B.J., Yin, L., Kim, S., Park, H., Lapidus, S.H., Klie, R.F., Key, B., Zapol, P. and Ingram, B.J., 2020. High capacity for Mg2+ deintercalation in spinel vanadium oxide nanocrystals. ACS Energy Letters, 5(8), pp.2721-2727. Yoo, H.D., Jokisaari, J.R., Yu, Y.S., Kwon, B.J., Hu, L., Kim, S., Han, S.D., Lopez, M., Lapidus, S.H., Nolis, G.M. and Ingram, B.J., 2019. Intercalation of magnesium into a layered vanadium oxide with high capacity. ACS Energy Letters, 4(7), pp.1528-1534.

The Remodulation of Actin Bundles during the Stimulation of Mitochondria in Adult Human Fibroblasts in Response to Light.

β-actin belongs to cytoskeletal structures that change dynamically in cells according to various stimuli. Human skin can be considered as an organ that is very frequently exposed to various stress factors, of which light plays an important role. The present study focuses on adult human fibroblasts exposed to two types of light stress. Orange light with a wavelength of 590 nm was used here to stimulate the photosensitizer localized in the cells as a residual dose of photodynamic therapy (PDT). On the other hand, near-infrared light with a wavelength of 808 nm was considered for photobiomodulation (PBM), which is often used in healing processes. Confocal fluorescence microscopy was used to observe changes in intercellular communication, mitochondrial structures, and cytoskeletal dynamics defined by the remodulation of β-actin of fibroblasts. The number of β-actin bundles forming spherical structures was detected after light exposure. These structures as β-actin oligomers were confirmed with super-resolution microscopy. While PDT led to the disintegration of actin oligomers, PBM increased their number. The interaction of β-actin with mitochondria was observed. The combination of PDT and PBM treatments is important to minimize the side effects of cancer treatment with PDT on healthy cells, as shown by the cell metabolism assay in this work. In this work, β-actin is presented as an important parameter that changes and is involved in the response of cells to PDT and PBM.

Ionic Liquid - Glyme Mixtures to Modify Solvation Chemistry, Electrochemical and Physiochemical Properties in Lithium Containing Electrolytes

Pyrrolidinium-based ionic liquids are an intriguing material for lithium-based battery electrolytes due to their inherit non-flammability and large electrochemical windows. Poor lithium-ion transport in ionic liquid-based electrolytes hinder the effectiveness of these electrolytes. Solvate ionic liquids were introduced as a subclass of ionic liquids consisting of high concentrations of lithium salts and glymes. For example, the solvate ionic liquid Li(G4)TFSI is an equimolar ratio of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (G4). In this work, pyrrolidinium-based ionic liquids containing short polyether side chains, structurally analogous to glymes, are mixed with equimolar amounts of LiTFSI and varying portions of G4. These tertiary mixtures were evaluated based on the ratio of solvating oxygen to lithium ion ([O]/[Li+]) present in the mixture. Trends in the oxidative stability, conductivity and lithium transference number were evaluated from mixtures of [O]/[Li+] between 5 to 8. Oxidative stability of tertiary mixtures with [O]/[Li+] = 5 showed improved oxidative stability compared to the binary Li(G4)TFSI, while [O]/[Li+] > 5 had diminished oxidative stability. DSC thermal analysis between -85°C to +120°C showed the tertiary mixtures helped suppress the glass transition temperature of Li(G4)TFSI to lower temperatures. Changes in the solvation structures were evaluate using spectroscopic analysis, including Raman spectroscopy. The changes in the solvation chemistry were correlated to the physiochemical and electrochemical properties.

Development of Operando Spectroscopy Measurement Technique for Single-Electrode Particle

ObjectiveSingle-particle electrochemical measurements have been desired to obtain essential electrochemical information on electrode materials. Currently, an electrochemical measurement method using micrometer order current-collecting probes (direct probe contact method) has been proposed to evaluate electrochemical properties for obtaining constant current charge-discharge and AC impedance data 1) 2). On the other hand, the structural change of electrode materials and their interfaced charge-discharge can be measured (Operando) by the spectroscopic method. Direct probe connection between polished microprobe and micrometer scale active material particle prevents sufficient irradiation of spectroscopic light, such as Raman light. This study uses the Operando technique of in-situ spectroscopic measurement for electrode active material particles under electrochemical reaction conditions by grasping a single active electrode particle with precision tweezers.ExperimentIn this study, a micromanipulator, motorized precision tweezer controller, precision tweezers (SUS), and electrochemical measurement device were installed in the dry box (Dew point is less than -76.0 ℃). As shown in Fig.1, a Li foil (counter/reference electrode Φ16 mm) was attached to the SUS cup, a separator impregnated with electrolyte (1 mol-LiFSA /kg-ethylene carbonate (EC)) was placed, and a single particle of LiCoO2 (LCO; particle size 20~30 μm) was grasped and fixed into the electrolyte. After confirm the stable electrode potential of the LCO single particle held by precision tweezers, various electrochemical measurements, and Raman spectroscopy measurements were performed during the charge-discharge process.Results and DiscussionFig.2 shows Raman spectra of LCO powder, electrolyte, and LCO single particle immersed electrolyte. Two sharp peaks originating from the Co-O stretching vibration and O-Co-O angular vibration3) were detected in the (Ⅰ) wavenumber range. In addition, a group of sharp peaks derived from electrolyte was observed in the range of (Ⅱ), attributed to the S-N-S stretching motion of FSA- and the O-C-O stretching motion of EC4). Therefore, this system enabled to obtain of Raman spectra of both LCO and electrolyte at the same time by using precision tweezers and a single particle. This technique enabled the observation of not only the structural changes of LCO according to charge-discharge reactions but also concentration changes owing to their changes in Li cation transport of the electrolyte at the electrode interface.To observe the solvation/desolvation behavior of the interface of electrolyte / Li metal, a micro-current collector (Cu wire: Φ 30 μm) was applied for a simplification experimental method, the Operando Raman spectroscopy measurements were performed during the Li deposition/dissolution test was conducted by cyclic voltammetry with the cell immersed in the electrolyte. The potential was swept to the negative side from OCV, and Raman spectra changed from 100mV to -100mV vs. Li/Li+. Li dendrites occurred below -100mV vs. Li/Li+, resulting in a change in focus and loss of the Raman peak. Fig.4 shows the Raman spectra at each potential between 100mV and -100mV vs. Li/Li+. Each peak in Fig.4(a) was attributed to the free FSA anion and the bound FSA anion, respectively, and peaks in Fig.4(b) were attributed to free EC and solvated EC. The change in Raman spectra of the EC peaks was larger than in the FSA anion ones. The fraction of integrated intensity of between free and solvated EC exhibited clearly change from around -50 mV. The fraction of integrated intensity of free and bound FSA anions also changed significantly from 2000 to 500 mV and rapidly returned to the initial state with the Li deposition reaction around -50 mV. From this result, the decrease in the Li cation with the dissolution reaction could be observed from the Raman peaks. Changing the dissociation properties of salt were observed from the changing peak of FSA anion. Smooth association of salt between FSA anion and Li cation was observed at initial state of Li dissolution process. We will report that sufficient metal plating will be applied to tweezers for direct observation of Raman spectra for electrolyte interface, charge-discharge tests, and obtained Raman spectra analysis results.1) K. Dokko et.al., J. Electrochem. Soc., 148, A422-A426 (2001).2) T. Saito et.al., J. Phys. Chem. C, 124, 16758-16762 (2020).3) L. Le Van-Jodin et.al., J. Raman Spectrosc., 50, 1594-1601 (2019).4) B. Klassen et.al., J. Phys. Chem. B, 102, 4795-4801 (1998). Figure 1

Investigation of Transition Metal Oxides & Phosphates for Zn-Ion/Zn-Air Batteries

Being a champion in a portable electronics world, lithium-ion batteries (LIBs) are irreplaceable, but the scarcity of Li, high cost, and the inclusion of non-aqueous electrolytes make them relatively perilous and inefficient for grid-scale energy storage. Recently, the blooming aqueous Zn-ion batteries (ZIBs) have emerged as one of the pioneer candidates featuring the inherently safe nature of metallic Zn anode and its unique properties.[1] Vanadium-based compounds show fast ion diffusion and excellent reversible capacity because of their rich valence state of vanadium, facile distortion of V-O polyhedrons, and tuneable composition, which offers an excellent treasure house. Moreover, the different oxidation states of vanadium allow a higher degree of structural change and greater functional flexibility while incorporating multivalent cations into vanadium-based compounds. [2] The present work focuses on one V-based oxide cathode. The cathode, ZnV2O4, synthesized by a simple solid-state route, showed a reversible capacity of around 200 mAh/g at a current density of 500 mA/g. Ex-situ XAS suggested that there is a drastic change in V and Zn local environment, confirming that there is a structural transformation taking place. Further, we have pursued ex-situ TEM where segregation of the conversion product phases was seen, confirmed by the small crystalline domains present at the nanoscale regime. A detailed analysis will be discussed to verify that a phase transformation is happening and is getting amorphized in subsequent cycles using ex-situ TEM and XAS.Also, metal-air batteries are widely discussed and studied because of their high energy density. In this pursuit, highly efficient bifunctional electrocatalysts, non-noble such as Co metal-based phosphates/oxides, have been studied vividly.[3,4] Herein, we present a thorough study of three-dimensional ZnCo2(PO4)2 (ZCP), which showed excellent bifunctional activity compared to the benchmark catalysts, denoting the presence of many catalytically active Co sites in ZCP. The presence of asymmetric edge-sharing CoO5/CoO6 polyhedra enhances the net catalytic activity.[5] ZCP exhibited robust oxygen reduction and evolution (ORR and OER) activity with the onset of 0.87 and 1.50 V vs. RHE for ORR and OER, respectively. The ORR saturated current density for ZCP was 6.38 mA/cm2, close to the 20% Pt/C catalyst benchmark. It also showed an OER exchange current density of 16.7 mA/cm2, closer to RuO2 ( j= 17.6 mA/cm2). This bifunctional electrocatalytic activity will be elaborated using analytical tools and DFT, along with the demonstration of Zn-air batteries. A detailed structural characterization using synchrotron refinement, TEM analysis, magnetic studies, and electrocatalysis performance will be discussed. Reference s : [1] M. Song et al., Adv. Funct. Mater. 2018, 28, 1802564.[2] Yao. Zhang et al., Chem. Front. 2021, 5 744-762.[3] J. L. Jung et al., Energy Environ. Sci. 2016, 9176-183.[4] W. Liu et al., Acc. Chem. Res . 2018,51,1858.[5] A. Baby et al., Chem. Comm. 2020, 56, 8400-8403.

Role of non-governmental organizations in post-relocation support of reservoir migrations in China: a just transition perspective

In recent decades, energy transition has been a major structural change worldwide to replace fossil fuels. Hydropower is a valuable renewable energy source which can mitigate the electricity demand of livelihoods and help to achieve the target of carbon neutrality goals. However, owing to the hydropower construction, involuntary resettles are suffering with land and socio-economic security. Non-governmental organizations (NGOs) play a vital role in promoting a just transition for reservoir migrants. The present study examines the work of local NGOs in a reservoir resettlement area in China through semi-structural interviews, and participant observations followed by qualitative analysis. Study explores how the NGOs organize reservoir migrants to participate in post-relocation support (PReS) projects. The study finds that the organized participation of reservoir migrants in PReS is the key process required to achieve a just transition. Moreover, NGOs ensure that all affected reservoir migrants have equal access to development opportunities through the three linked levels of co-construction, co-management, and co-sharing through the elite-driven establishment of benefit linkages and fair benefit distribution, and ultimately achieve a standard of living for migrants. Organized participation improves the equity and sustainability of benefits for reservoir migrants, but organizing reservoir migrants requires firm support from the local, regional and national governments, and the trust of migrants in local NGOs. Findings further stated that the PRes policy still has some blank spot, therefore, it is necessary to frame robust policy frameworks to restore the livelihoods of reservoir migrants.

Monitoring of Energy Storage Mechanism of Zn/Meso-MnO2 Battery System Using X-Ray Absorption Fine Structure

As energy storage systems, LIBs, which are most frequently used, have excellent capacity, power, and long lifespan performance [1]. However, as the reserves of the raw minerals used—lithium and cobalt—are exhausted, prices are escalating. A further issue with LIB is that it heats up to a high temperature during charging, which leads to a string of fire or explosion catastrophes. To solve these safety or cost challenges, various next-generation batteries are being developed, and we are exploring about aqueous zinc ion battery (AZIB), which attracting attention as the next-generation battery due to outstanding safety and cost competitive advantage. Generally, zinc metal acting as an anode, has a high theoretical capacity of 820mAh/g as it is gives two electrons (2e-). Also, because of its sparse reactivity with water and ability to employ water-based electrolytes with strong ion conductivity and low ignition risk, it is particularly advantageous in terms of safety. There have been a variety of cathode materials utilized, such as manganese oxide, vanadium oxide, Prussian blue analogues (PBAs), polyanion compounds, and Chevrel phase compounds [2-4]. Especially, manganese dioxide (MnO2) has been addressed by prior studies that Zn2+ can be inserted into crystal structure because it exhibits several crystal structures (α, β, γ, δ, and λ) with tunnel-type or layer-type structure. Mn4+ ions occupying octahedral holes formed by hexagonal close-packed (hcp) oxide ions compose the fundamental unit of the crystal structure of MnO2 polymorphs. To construct a [MnO6] octahedral unit, each Mn4+ ion is precisely surrounded by six oxygen neighbors, and these units are connected by the edges and/or corners [5]. Understanding the energy storage mechanisms is essential for the one-step evolution of cathode materials for AZIB. However, these polymorphs significantly affect the electrochemical reaction, thus involving complex reaction mechanisms [5-7]. Additionally, it is extremely challenging to research the mechanisms of AZIB since protons (H+) are known to participate in the reaction by acting as charge transfer as well as Zn2+ ions. Therefore, while several efforts are being conducted to unveil the exact reaction mechanism, a mesoporous nanostructured material with a large specific surface area is adopted, which can more precisely grasp the electrochemical reaction studies of electrode/electrolyte surface [8,9]. X-ray absorption fine structure (XAFS) is a powerful technique used for the analysis of nanostructured materials, widely used in the field of battery research [10]. It involves the measurement of the absorption of X-ray by the material, which can provide information about oxidation state, chemical bonding of the materials and the local geometry structure during charge/discharge process. This analysis method gives great insight into the complex energy storage pathway of MnO2 materials with various polymorphs. Based on this knowledge, we synthesized ordered mesoporous β-MnO2 through nano-casting method by using KIT-6 as hard-template and used it as the cathode active material. As depicted in Figure 1, we performed ex-situ XAFS analysis at the states of charge during 2nd cycle to monitor energy storage mechanisms. The oxidation state changes could be quantitatively estimated by edge energy analysis by comparing the reference MnO2 and Mn2O3 samples. It was also possible to unveil further about the reaction mechanism at each voltage by examining the structural change in the local geometry of [MnO6] unit through a careful analysis of pre-edge region and EXAFS spectra. During discharge process, insertion mechanism, which causes relatively larger distortion in the local geometry compared to conversion mechanism, results in a increment of pre-edge intensity, which opposes the decline in pre-edge intensity due to the reduction of the oxidation state. This fact demonstrates that although H+ conversion could not have a significant effect on pre-edge intensity in the early discharge stage, Zn2+ insertion was the phenomenon responsible for the rise in pre-edge intensity during late discharge stage. In addition, through EXAFS spectra analysis, the irreversible change in corner sharing Mn-Mn bond distance during charge/discharge process could be seen that an irreversible phase transition of MnO2 occurred due to Zn2+ insertion, indicating clue to identify the cause of capacity fading. These findings contribute to further understanding of the reaction mechanisms and capacity fading phenomenon and suggest practical strategies for next-generation zinc-ion batteries.

NMC811 Electrodes with High Mass Loadings Enabled By Non-Solvent Induced Phase Inversion

Higher energy density Li-ion batteries that can enable longer driving ranges are currently subject to intensive research interest. Increasing the thickness of electrodes and reducing the proportion of inactive components per cell is one way to achieve this. In thick electrodes, a higher electronic and ionic overpotential and mechanical failure (cracking, delamination etc.) induced by binder migration during the drying process leads to sluggish (dis)charge performance or even cell failure respectively. Here we report non-solvent induced phase inversion as a scalable, effective method to arrive at thick NMC811 electrodes.By tuning the non-solvent properties and other processing conditions to be compatible with Ni-rich electrodes, it was possible to obtain NMC811 electrodes with mass loadings up to 11 mAh/cm2 (single sided) which outperform their conventional processed counterparts in Li/NMC half cells. This improvement could be attributed to the altered carbon-binder structure, which improves the pore connectivity and lowers the electrode tortuosity factor. The rapid solvent removal also reduces the long-range binder migration during drying. With imaging and porosimetry techniques we show the structural change which leads to the observed improved electrochemical performance. The method also shows good compatibility with double sided slot-die electrode coating procedure, making this a technique with potentially high industrial feasibility towards making thicker NMC811 and other electrodes.

Aptamer-based flares hybridized with single-stranded DNA-conjugated MoS2 nanosheets for ratiometric fluorescence sensing and imaging of potassium ions and adenosine triphosphate in human fluids and living cells

Addressing the limitations observed in previous studies, where the quantitative range of nanoprobes for detecting K+ and adenosine triphosphate (ATP) did not cover concentrations found within living cells, the present study aimed to develop ratiometric nanoprobes that can accurately sense changes in K+ and ATP levels in living cells and quantify them in human fluids. The proposed nanoprobes consisted of recognition flares modified with 6-carboxyfluorescein (FAM) and 5-carboxytetramethylrhodamine (TAMRA), along with thiolate single-stranded DNA (ssDNA) and molybdenum disulfide nanosheets (MoS2 NSs). The thiolate ssDNA acts as a linker between the flares and the MoS2 NSs, directly forming a functional nanostructure at room temperature. The direct conjugation of labeled flares to the MoS2 NSs simplifies the fabrication process. In the absence of K+ and ATP, the hybridization of flares and thiolate ssDNA caused FAM to move away from TAMRA, suppressing the fluorescence resonance energy transfer (FRET) process. However, upon the introduction of K+ and ATP, the flares undergo a structural transformation via the formation of G-quadruplex formation and the generation of hairpin-shaped structures, respectively. This structural change leads to the release of the flares from the ssDNA-conjugated nanosheet surface. The release of the flares brings FAM and TAMRA into close proximity, allowing FRET to occur, leading to FRET and static quenching. By monitoring the ratio between the fluorescence intensities of FAM and TAMRA, the concentration of K+ (5–100 mM) and ATP (0.3–5 mM) can be accurately determined by the proposed nanoprobes. The advantages of these nanoprobes lie in their ability to provide ratiometric measurements, which enhance the accuracy and reliability of the quantification process. The proposed nanoprobes offer potential applications as ratiometric imaging probes for monitoring K+ and ATP-related reactions in living cells, providing valuable insights into cellular processes. Additionally, they can be employed for determining the levels of K+ and ATP in human fluids, offering potential diagnostic applications in various clinical settings.

The Influence of Doping in the Electrocatalytic Properties of NiFe2O4-Derived Nitrides

Transition metal nitrides (TMNs) have been widely studied in the last years due to their extraordinary properties such as high electrical conductivity and versatile physical and chemical properties. They can be easily synthesize from metal oxide precursors and, in addition, they display electrocatalytic activities similar to Pt and other conventional noble metal electrocatalysts.1 Among them, several Ni-, Co- and Fe-based nitrides have been studied as electrocatalysts for the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).2–4 The combination of these metals in different proportions (stoichiometric and non-stoichiometric) can give place to a wide range of electrocatalysts with better electrochemical performance than the single metal nitrides. Apart from them, 2nd and 3rd row TMNs like Mo- and W-based nitrides can display high HER activity, surpassing those 1st row TMNs above-mentioned, therefore doping 1st row TMNs with Mo or W, even in very small amounts, can increase significantly the electrocatalytic performance of these materials.5 In this work, NiFe2O4-derived nitrides and their Mo- and W-doped versions were synthesized via the resorcinol-formaldehyde sol-gel polymerization method, followed by nitridation in ammonia atmosphere. The influence of doping for the HER, ORR and OER reactions in alkaline electrolyte has been studied. As observed, W-doping results in improved ORR and OER activities. Characterization techniques, such as XRD, TEM and XPS, are being performed in the initial and used catalysts, observing a structural change from the initial oxide (NiFe2O4) to the final nitride (NiFe2N), including the doped versions, which can help to understand their electrocatalytic properties.

Electron microscopic changes in interstitial endocrinocytes of rats testicles during administration of triptorellin for 365 days

Triptorelin is a gonadotropin-releasing hormone agonist that is a potent inhibitor of testosterone (in men) and estrogen (in women) synthesis and is used to treat advanced prostate cancer. Studies of the mechanisms of regulation and synthesis of testosterone formation in testicular interstitial cells demonstrate multiple endogenous targets that can increase testosterone biosynthesis, which may moderate the effects of testosterone depletion. Triptorelin, a synthetic analog of the neurohormone gonadoliberin, suppresses the expression of the GnRH receptor in the pituitary gland, but does not change the functioning of the pituitary-testicular complex. The purpose of the work is to study the electron microscopic changes in the interstitial endocrinocytes of the testes of rats after the administration of triptorelin for 365 days. The experiment was conducted on 35 sexually mature male white rats. The rats were divided into 2 groups: the control group (I) was injected with a physiological solution, the II group with central deprivation of the synthesis of luteinizing hormone was injected subcutaneously with triptorelin at a dose of 0.3 mg of the active substance per kg of the rat's body weight. The study of the interstitial space in the testicles of white rats showed that long-term administration of triptorelin causes hormonal dysregulation of the hypothalamus-pituitary-testis system, which leads to quantitative and qualitative changes in the endocrine cells of the interstitial space of the testis, which is confirmed by electron microscopic changes in subcellular structures. The maximum effect of triptorelin is determined from the 180th day of observation, which is characterized by an increase in degenerative changes in endocrinocytes, and the detection of Reinke crystals in the cytoplasm of interstitial endocrinocytes from the 270th day of observation.

Unlocking the print of poly(L-lactic acid) by melt electrowriting for medical application

Melt electrowriting (MEW) is an advanced 3D printing technology to process high-resolution scaffolds. Although MEW has printed many biodegradable polymers, most of them have low printability, including poly(L-lactic acid) (PLLA) discussed in this study. While the print of PLLA scaffolds by MEW is elementarily realized, the scaffolds' limited structural change and mechanical properties influence their application. This study aims at improving the printability and the mechanical properties of the PLLA. To this end, the printability of the PLLA regarding jet lag angle and critical translation speed is investigated; the print limitation of PLLA is discovered, and the uniaxial and cyclic tensile tests for the scaffolds in linear and nonlinear structures are carried out. The results suggest that drying the PLLA before printing can significantly restrain polymer degradation to extend the printing period to approximately one day; planar PLLA scaffolds are able to reach 25 layers, 100 µm interfiber distance, and 8 × 8 cm2 in dimension, and tubular PLLA scaffolds with 6 layers are successfully printed out; the mechanical properties of the PLLA scaffold reach the level of electrospun nonwoven fabrics. Thus, this study is a milestone work for the MEW technology to extend the printable materials.

Unraveling Halochromism of Azo‐Based Sulphonamide and Its Real‐World Applications: A Combined Experimental and Theoretical Approach

AbstractHalochromic azo dyes have versatile applications, including sensing and anti‐counterfeiting, due to their reversible color‐changing properties. In this work we investigated the structure‐dependent halochromism of azo compound (E)‐4‐((2‐hydroxynaphthalen‐1‐yl)diazenyl)benzenesulfonamide (HDBS) and explore its potential applications using experimental and theoretical approaches. Different spectroscopic techniques confirm the structural change in the dye as a consequence of tautomerism reaction upon changing pH (7 to 13). The stable form of hydrazone is isolated and characterized. Based on the spectroscopic characterization, it is concluded that the azo form exists at pH ≤ 9, whereas the hydrazone form at highly alkaline pH. To understand the origin of the absorption peaks, the stability, and tautomerism in water, DFT and TD‐DFT calculations are performed. A reasonable agreement between the theoretical and experimental observations enabled us to unravel the structure‐dependent halochromism. Further, we have shown that HDBS‐coated paper can be a real‐time visual sensor to monitor fish freshness and for anti‐counterfeiting ink. It changes colors with pH shifts, alerts consumers about the status of food. Additionally, erasable paper strip reduces paper waste and chemical pollution. The findings presented in this work provide a promising avenue for the development of halochromic azo compounds with potential applications in sensing and anti‐counterfeiting.

Numerical simulation of strength and failure analysis of heterogeneous sandstone under different loading rates

Natural rock masses often contain heterogeneous structures with varying sizes, non-uniform distributions, and strengths, which influence the mechanical response characteristics and crack propagation modes under loading. Furthermore, heterogeneous structures can affect the stability of the rock mass, in serious cases, leading to geotechnical and mining engineering disasters. In the present work, a parallel-bond model (PBM)-based numerical simulation using Particle Flow Code (PFC) was carried out to study the strength and failure characteristics of sandstone specimens with heterogeneous structures under different loading rates. The results show that the peak strength increases with the increasing loading rate. In addition, all of the initial cracks occurred at the edges of the heterogeneous structures of specimens under different loading rates. The greater the loading rate, the greater the stress concentration degree at the edge of the heterogeneous structures, the greater the dissipated energy as the sandstone specimens with heterogeneous structures suffer damage, the more intense the acoustic emission activity, and the greater the damage degree of the specimens. The number of cracks generated in sandstone specimens with heterogeneous structures increases gradually with the increasing loading rate during the initial loading stage, and gradually decreases after the specimens are damaged. Cracks propagate and develop from the upper right region to the lower right region of the specimens, forming crack groups that rapidly penetrate the specimens, leading to failure. Under different loading rates, the final failure behavior of the sandstone specimens with heterogeneous structures changes from an inverted V-type to θ-type, then gradually evolves to O-type failure.

Manothermosonication, high-pressure homogenization, and their combinations with pH-shifting improve the techno-functionality and digestibility of hemp protein

The growing interest in plant-based proteins, particularly hemp protein, has driven the exploration of new methods to address the limitations of its industrial utilization, such as its poor functional properties. This study examined how manothermosonication (MTS) and high-pressure homogenization (HPH) techniques, along with pH-shifting, could enhance the techno-functionality of hemp protein isolate (HPI) and produce functionalized hemp protein nanoaggregates. Optimal processing conditions of MTS were 50 °C, 200 kPa, and 90 s, as determined by response surface methodology. The pH-shifting + MTS and pH-shifting + HPH treatments reduced the size of hemp protein nanoaggregates by 3.2- and 1.9-fold, respectively, compared to the untreated HPI. The changes in secondary (FTIR, CD), tertiary (SH group, fluorescence intensity), and 3D structures (XRD) confirmed modifications of treated hemp proteins. The XRD patterns showed an increase in the %crystallinity values from 21% to 29% upon the pH-shifting + MTS treatment. The combination of pH-shifting + MTS resulted in the highest solubility and digestibility, 2.1- and 1.3-fold higher than the untreated HPI, respectively, followed by the MTS-alone and HPH treatments. In addition, the emulsion properties (emulsion activity, stability, creaming index, and droplet sizes) exhibited the highest values in HPI treated by pH-shifting + MTS and + HPH. The MTS and HPH technologies provide a promising viewpoint for producing protein nanoaggregates with enhanced functional properties for microencapsulation, edible film, and other applications.

Alkylation of Toluene to Mono‐benzylated Toluene over Micro‐mesoporous Zeolite: Effect of Post‐synthetic Treatment and Catalytic Application

AbstractPost‐synthetic modification using acid (HNO3) and base (NaOH) are utilised to synthesize hierarchical micro‐mesoporous zeolites with different pore structure. To investigate structural change in materials, X‐ray diffraction (XRD), Scanning electron microscope (SEM), Inductive coupled plasma‐optical emission spectrometry (ICP‐OES), 29Si and 27Al MAS NMR, and N2 adsorption‐desorption isotherms techniques were employed. Acid base titration, and ammonia‐temperature programmed desorption (NH3‐TPD) was performed to evaluate acidic characteristics of materials. As revealed by characterisation, the structure was well preserved after the modification. Hierarchical materials along with parent materials have been evaluated in the toluene alkylation with benzyl alcohol producing mono‐benzylated toluene. All zeolite samples were proved to be catalytically active by their result in the alkylation reaction. Acid treated samples were compared with base treated and parent samples. The results indicate that, base modification significantly increases the mesoporous pore volume in all zeolite as compared to acid modification. Moreover, the highest benzyl alcohol conversion was found to be 98 % in the base modified Beta, with the highest mono‐benzylated toluene selectivity (69 %). Reaction optimization was also studied by altering reaction duration, temperature, and catalyst amount. The reaction products were analysed using Gas Chromatography (GC) and confirmed using Gas chromatography mass spectrometry (GC‐MS).

Stability of ion-beam-induced bixbyite phase in δ-Sc4Hf3O12 under heat treatments and electron beam irradiations

Oxygen-deficient compounds A4B3O12 have a δ-type structure with a regular long-range arrangement of oxygen vacancies induced by compensation of the charge difference between A3+ and B4+ cations, while A and B cations do not order long-range and only display weak short-range correlations. The δ-type compounds in the Sc2O3-HfO2 and Sc2O3-ZrO2 systems exhibit excellent resistance to radiation-induced amorphization, but the long-range ordered δ-phase was transformed into a short-range ordered bixbyite phase. Since this structural change was not predicted from the phase diagram, the validity of the formation of the bixbyite phase and its stability are still unclear. In the present study, the changes of radiation-induced microstructures in δ-Sc4Hf3O12 under heat treatments and electron beam irradiations were examined by ex-situ and in-situ transmission electron microscopy. It was found that the ion-beam-induced metastable bixbyite phase is transformed into the δ and fluorite phases by the rearrangement of the oxygen vacancies.

Impacts of in situ urbanisation on grain production: Evidence from the Yangtze River Delta, China

With the promotion of county-level urban–rural integrated development policies in China, counties in economically developed regions have achieved sound in situ urbanisation (ISU), resulting in changes in regional population and production structures. However, to date, relatively few studies have focused on the ISU process and the variation in regional grain production in the Yangtze River Delta (YRD). This study evaluated the ISU rate (ISUR) at the county level using the entropy based TOPSIS model, introduced a super efficiency slacks-based measure (SBM) model to calculate cropland production efficiency (CPE), and reflected the status of grain production from grain yield and CPE. Spatio-temporal dynamics of ISU and grain production were examined from 2000 to 2020, and the impact mechanism of ISU on the grain production were explored encompassing regional differences and spatiotemporal evolution. The ISUR of the YRD showed a high distribution in the east and low in the west, with all counties showing a continuous increase, and an average increase from 0.15 in 2010 to 0.33 in 2020. The most rapid increases occurred in northern Zhejiang, southern Jiangsu, and the coastal areas. The grain yield in the entire region was high in the north and low in the south, with a continuous increase in the north and a continuous decrease in the south. The CPE distribution changed from high in the south in 2000 to high in the north in 2020, with a higher growth rate in the north and a significant decrease in the south. The initial advancement of ISU promoted grain production. The plains with medium ISU levels showed the highest grain yield and CPE. Where the ISU level reached extremely high levels, it had a suppressive effect on grain production. In mountainous areas, the CPE and grain yield decreased during ISU. The findings of this study are of great value to policymakers in adjusting the regional agricultural production structure according to ISU stages to implement food security strategies in a regionally integrated manner.

Subfoveal and Parafoveal Choroidal Thickening in Patients with Keratoconus Using the ETDRS Grid on Swept-Source OCT.

There is growing evidence that confirms morphological changes in the posterior structures in patients with keratoconus (KC); however, isolated alterations could have been missed. This study assesses choroidal thickness (CT) in the fovea and beyond in KC eyes. This prospective case-control and non-randomized study enrolled 107 eyes, 62 eyes of 62 patients with KC, and 45 age-matched eyes of 45 control subjects with axial length in the range of 22-26mm. Swept-source optical coherence tomography (SS-OCT) was performed to manually measure the subfoveal choroidal thickness (SCT) using a single-line scan. CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid using the 12-lines radial scan pattern. A two-way repeated-measures analysis of variance (ANOVA) was conducted to evaluate CT variations among macular eccentricity, parafoveal area, and the interaction between both factors. CT was compared in all parafoveal areas between groups and subgroups of KC. SCT was significantly thicker in KC eyes (357 ± 57µm) than in healthy eyes (325 ± 63µm) (p < 0.001). Significant choroidal thickening was observed in the central ring and outer and inner rings of the temporal, superior, and inferior parafoveal macular areas (p < 0.001), except in the outer ring of the nasal macular zone (p > 0.05) of KC compared to healthy eyes. The CT significantly decreased from the center to the outer ring regardless of the presence of KC (p < 0.001). The choroid in the nasal macular zone was significantly thinner than that in the temporal, superior, and inferior parafoveal areas (p < 0.001). The choroidal structure increased its thickness not only in the subfoveal area, but also in eight parafoveal areas of the ETDRS grid encompassing a wider area of macular examination. These findings demonstrate and corroborate that keratoconus is not a purely corneal disease. Furthermore, it confirms the role that the choroidal structure has in the pathophysiology of keratoconus.

Topographic comparison of the retinal microvascular changes between patients with compressive and glaucomatous optic neuropathies

We investigated the difference in optical coherence tomography angiography characteristics between the patients with compressive optic neuropathy (CON, n = 26) and glaucomatous optic neuropathy (GON, n = 26), who were matched for the severity of visual field defect. The peripapillary retinal nerve fiber layer (pRNFL) thickness in the nasal and temporal sectors was thinner in the CON group, whereas the inferior pRNFL thickness was thinner in the GON group. Accordingly, the CON group had lower peripapillary vessel density (pVD) in the nasal and temporal sectors, and the GON group in the inferior sector. In the macular area, the CON group had a thinner macular ganglion cell-inner plexiform layer in the superior and nasal sectors, whereas the GON group in the inferior sector. However, the CON group did not have a lower macular VD than the GON group in any sector, whereas the GON group exhibited lower superficial capillary plexus VD in the superior, inferior, and temporal sectors. Comparison of the structure–vasculature correlation revealed a significant difference in the nasal and temporal peripapillary areas and superior and nasal macular sectors; a decrease in VD was greater in the GON group than in the CON group when the comparable structural change occurred.