Morphology Of Aggregates Research Articles

Amphiphilic salts as single-component, solvent-free, lithium electrolytes

Electrolytes with enhanced thermal stability are sought for next-generation lithium batteries. In this work, we discuss the synthesis, thermal properties, morphology, and ionic conductivity of single-component, solvent-free electrolytes composed of lithium salts with amphiphilic anions. These salts exhibit nanoscale phase segregation between the ionic domains and aliphatic tails of the amphiphilic anions. It is found that for a series of lithium salts with a decane tail, the ionic conductivity is correlated with ion pair binding energy. The ionic conductivity is highest for the decane tailed salt with the –sulfonyl(trifluoromethanesulfonyl)imide head group (LiC10TFSI) at 5.6 × 10–7 S/cm at 70 °C, with salts with – sulfonyl(phenylsulfonyl)imide and –sulfonylazanide anions exhibiting lower conductivity. A salt with an octadecane tail and TFSI headgroup (LiC18TFSI) has further improved ionic conductivity, 4 to 1000 times higher depending on the temperature and 3.6 × 10–5 S/cm at 70 °C. LiC18TFSI is a smectic ionic liquid crystal at intermediate temperatures as confirmed through X-ray scattering experiments and molecular dynamics simulations, whereas LiC10TFSI is suspected to be a disordered ionic liquid at the measurement conditions, highlighting the importance of ionic aggregate morphology on bulk ionic conductivity of electrolytes with ion clusters.

Characterization, Optimization, and Scaling-up of Submerged Inonotus hispidus Mycelial Fermentation for Enhanced Biomass and Polysaccharide Production.

This study was to establish an efficient strategy based on inoculum-morphology control for the submerged mycelial fermentation of an edible and medicinal fungus, Inonotus hispidus. Two major morphological forms of the mycelial inoculum were compared, dispersed mycelial fragments versus aggregated mycelial clumps. The dispersed one was more favorable for the fermentation, starting with a shorter lag period and attaining a higher biomass yield and more uniform mycelium pellets in shake flasks. The mycelial pellets taken from the shake flask culture on day 6 were fragmented at 26,000rpm in a homogenizer, and a shear time of 3min provided the optimal inoculum. The inoculum and culture conditions were further verified in 5-L stirred tank fermenters and then the fermentation was scaled-up in a 100-L stirred tank. With the optimized inoculum and process conditions plus a fed-batch operation, much higher productivities, including 22.23g/L biomass, 3.31g/L EPS, and 5.21g/L IPS, were achieved in the 100-L fermenter than in the flask culture. A composition analysis showed that the I. hispidus mycelium produced by the fermentation was rich in protein, dietary fiber, and polysaccharides which may be beneficial to health. Overall, the results have shown that the inoculum characteristics including age, morphology, and state of aggregation have significant impact on the productivity of mycelial biomass and polysaccharides in a submerged mycelial fermentation of the I. hispidus fungus.

Enhancement of Alkaline OER Performance of the Electroplated Ni-P Catalysts Using Electrochemical Dealloying Technique

With the growing attention on renewable energy, hydrogen is receiving attention as an energy carrier to resolve the temporal and spatial constraints of renewable energy. Electrical energy generated from renewable energy can be efficiently stored and transported in the form of hydrogen. Here, water electrolysis consists of two reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the high activation energy of OER is the main bottleneck of water electrolysis. Consequently, highly active catalysts are indispensable. Currently, the Pt- and Ir-based noble metal catalysts boast the highest performance for OER, but face significant commercialization hurdles due to their high cost.Transition metal-based compounds are promising as substitutes of Platinum group materials for OER catalysts due to their high catalytic activity and earth-abundant properties. In particular, transition metal phosphides (TMPs) such as Ni-P are receiving much attention due to its remarkable catalytic performance approaching that of Pt-based one. In Ni-P, electrons are transferred from Ni to P due to the difference in electronegativity, allowing the energy of the HER and OER intermediate to be controlled for optimal activity. Furthermore, the Ni-P synthesized through electrodeposition has high potential as a promising substitute because they can have a variety of P ratios on the N-P surface, that can significantly affect catalytic activity and improve it more. Unfortunately, however, the electrodeposited Ni-P mostly has a flat and aggregated morphology, resulting in a low surface area and hence low catalytic performance. Therefore, to maximize the catalytic performance of the electroplated Ni-P. it is necessary to increase in surface area and number of active sites as well as the optimization of surficial P ratio.In this context, we propose a morphology control method using electrochemical dealloying, which can greatly increase the surface area of the electroplated Ni-P. Specifically, under acidic conditions, a potential higher than the reduction potential of Ni causes partial dealloying of Ni on the Ni-P catalyst. Then, the partial dealloyed Ni creates defects between grains and forms a porous structure. As a result, the surface of the dealloyed Ni-P catalyst was exposed along the grain boundaries through SEM, and a quantitative increase in surface area was confirmed through cyclic voltammetry (CV). In addition, it was confirmed through XPS analysis that the bond between Ni and P became stronger, and based on this, it was confirmed that the tafel slope and TOF of the catalyst increased. The increase in overall performance of the catalyst was confirmed through the polarization curve as surface area and intrinsic activity increased. Figure 1

Unraveling a Novel Degradation Mechanism in Industrial Scale PEM Electrolytic Cells by Multimodal Analysis Based on X-Ray Computed Tomography

Proton exchange membrane electrolytic cell (PEMEC) is a key technology in the production of sustainable “green” hydrogen. In such systems, as an electrolyte and physical barrier, a proton exchange membrane (PEM) is applied [1]. Overall, the performance of a PEMEC depends on many factors, such as the catalyst material and its loading, the thickness of electrodes and membrane and the interface roughness for example. While studies have reported changes in PEM microstructures, even in operando [2], there is still limited data regarding process heterogeneity in large industrial-scale cells operating over long periods. However, enhancing the performance and durability of PEMEC is crucial to propel this technology forward, enabling its up-scaling and market introduction on an industrial level.In this study, we investigated the morphology and degradation mechanisms of membrane electrode assemblies (MEAs) in PEMEC using a multimodal analytical approach. The investigated MEAs, which were operated for 5000 hours, consisted of an Ir coated anode and a Pt cathode and were as large as several hundred cm².Firstly, the morphology of post-test MEAs was analyzed by the means of X-ray computed tomography (XCT). Here, a measurement protocol provided imaging data at multiple scales. Furthermore, the field-of-view was greatly increased by rolling the MEA and later unwrapping the reconstructed image. A simple, yet robust segmentation algorithm, allowed to automatically delineate features like agglomerates and cracks inside the electrodes post-test. This thorough XCT study led to the discovery of a novel degradation mechanism in PEMEC, which, to the best of our knowledge, has not yet been discussed in literature. The found morphological anomaly was linked to electrochemical behavior of the cell by analyzing electrochemical impedance spectra (EIS) and measuring the gas permeation through the MEA. Current sensing atomic force microscopy (AFM) was used to analyze the electrical properties in the vicinity of the detected anomalies.Additionally, metallographic techniques such as focused ion beam scanning electron microscopy (FIB/SEM) and transmission electron microscopy (TEM), combined with energy-dispersive X-ray spectroscopy (EDS) and Raman spectroscopy, provided high-resolution local morphology and the chemical composition within the affected regions. Finally, after collecting all this data, we were able to propose physical 1-D and 3-D models for the observed phenomena and their effects on PEMEC.In conclusion, this study on a previously unknown degradation mechanism inside MEAs demonstrates the significance of a multimodal analytical approach when it comes to detecting, understanding and mitigating the degradation in PEMEC. Such an approach will further pave the way for enhanced performance and durability in PEMEC on an industrial scale.[1] B. Han et al., Electrochimica Acta, 2016, 188, 317-326.[2] E. Leonard et al., Sustainable Energy Fuels, 2020, 4, 921-931. Figure 1

Aggregate Science: from Molecules, beyond Molecules.

Over the past centuries, molecular science has played a dominant role in the advancement of physical science by exploring the structure-property relationships at a single molecular level. However, when molecules form aggregates, a dilemma arises as the structures and properties often differ significantly from those of molecular constituents. To address this, the concept of aggregate science emphasizes a holistic approach to understanding the structures-properties relationship of substances. Despite the recognition of holism in aggregate research, there are still challenges in investigating the complex operations and interplays, particularly in understanding the newly emergent structures and properties in the macroscopic world. Therefore, there is a need to further advance the concept and methodology. In this regard, this perspective highlights three types of influences that aggregation exerts on substance properties: activation, transformation, and emergence. Furthermore, examples from aggregation-induced emission research and related fields are provided to illustrate how aggregate science can be studied. This perspective emphasizes that the molecule is of significance and the structures and properties are also dramatically influenced by aggregation. Additionally, potential research methodologies, such as focusing on intra- and intermolecular interactions, adjusting aggregates morphology, and regulating the constituents, along with directions, and implications are offered for future studies.

In Vitro Cell Model Investigation of Alpha-Synuclein Aggregate Morphology Using Spectroscopic Imaging.

Recently, it has been hypothesized that alpha-synuclein protein strain morphology may be associated with clinical subtypes of alpha-synucleinopathies, like Parkinson's disease and multiple system atrophy. However, direct evidence is lacking due to the caveat of conformation-specific characterization of protein strain morphology. Here we present a new cell model based in vitro method to explore various alpha-synuclein (αsyn) aggregate morphotypes. We performed a spectroscopic investigation of the HEK293 cell model, transfected with human wildtype-αsyn and A53T-αsyn variants, using the amyloid fibril-specific heptameric luminescent oligomeric thiophene h-FTAA. The spectral profile of h-FTAA binding to aggregates displayed a blue-shifted spectrum with a fluorescence decay time longer than in PBS, suggesting a hydrophobic binding site. In vitro spectroscopic binding characterization of h-FTAA with αsyn pre-formed fibrils suggested a binding dissociation constant Kd < 100 nM. The cells expressing the A53T-αsyn and human wildtype-αsyn were exposed to recombinant pre-formed fibrils of human αsyn. The ensuing intracellular aggregates were stained with h-FTAA followed by an evaluation of the spectral features and fluorescence lifetime of intracellular αsyn/h-FTAA, in order to characterize aggregate morphotypes. This study exemplifies the use of cell culture together with conformation-specific ligands to characterize strain morphology by investigating the spectral profiles and fluorescence lifetime of h-FTAA, based upon its binding to a certain αsyn aggregate. This study paves the way for toxicity studies of different αsyn strains in vitro and in vivo. Accurate differentiation of specific alpha-synucleinopathies is still limited to advanced disease stages. However, early subtype-specific diagnosis is of the utmost importance for prognosis and treatment response. The potential association of αsyn aggregates morphotypes detected in biopsies or fluids to disease phenotypes would allow for subtype-specific diagnosis in subclinical disease stage and potentially reveal new subtype-specific treatment targets. Notably, the method may be applied to the entire spectrum of neurodegenerative diseases by using a combination of conformation-specific ligands in a physicochemical environment together with other types of polymorphic amyloid variants and assess the conformation-specific features of various protein pathologies.

Characterisation, comparison of surface topography and frictional resistance of zinc oxide- tin oxide nanocoated ceramic orthodontic brackets by radio frequency magnetron sputter coating method: An in vitro study

In recent years, orthodontic research has witnessed significant progress as it ventures into the exploration of nanoparticle coating to augment the surface properties of orthodontic appliances. The present study aimed to evaluate the surface characteristics, surface topography and frictional resistance (FR) of ceramic brackets (CB) nanocoated with zinc oxide- tin oxide (ZnO-SnO) by radio frequency magnetron sputter coating method.26 polycrystalline maxillary canine CB, split into two groups, were used in the current in vitro investigation. Group A of the RF magnetron sputter coating method was used to coat ZnO-SnO nanoparticles (Nps) on brackets, while group B of the process used uncoated brackets. Following coating, brackets underwent EDAX and SEM imaging. Atomic force microscopy (AFM) was used to assess the surface topography, and frictional resistance (FR) was also examined. An analysis of the data was conducted using SPSS (Version 23.0). An independent parametric t-test was used to compare the results between the groups.Brackets coated by RF sputter coating method had a porous and aggregated morphology when viewed under SEM. EDAX spectroscopy images showed uncoated brackets presented aluminium, oxygen, silica and calcium signal peaks at 60.83 wt %, 13.43 wt %, 24.57 wt % and 1.17 wt % respectively while the coated brackets showed signal peaks of zinc, oxygen, silica and tin at signal peaks of 20.98 wt %, 54.85 wt %, 10.52 wt % and 13.65 wt %. Groups A and B showed a surface roughness (SR) of 180.62 ± 9.49 nm and 316.77 ± 14.10. A statistically significant difference was observed in the SR between the 2 groups (p=0.00). The mean FR were higher for uncoated brackets (8.18 ± 0.76) p=0.00.Zn-SnO2 Nps were effectively coated onto ceramic brackets through the RF magnetron sputter coating technique. In comparison to uncoated brackets, the coated brackets exhibited a lower FR and SR.

Aggregate morphing of self-aligning soft active disks in semi-confined geometry

We study the dependence of alignment and confinement on the aggregate morphology of self-aligning soft disks(particles) in a planer box (two dimensional) geometry confined along y direction using Langevin dynamics simulations. We show that when the box width decreases, the aggregate wall accumulation becomes non-uniform and displays non-monotonic behaviour in terms of phase behavior and height of these aggregates with an increase in alignment strength. Additionally, we identify two distinct categories of wall aggregates: layered and non-layered structures each exhibiting distinct local structural properties. For non-layered structures, local speed of the particles stay nearly constant as we move away from the boundary, while for layered structures, it increases with distance from the boundary. Our analysis shows that active pressure difference is a useful indicator for different aggregate morphologies and the peaks in the pressure curve are indicative of the average and minimum height of the structure.

A Multimode fluorescent sensor for sequential detection of Cu2+ and cysteine as well as pH sensor with real sample Applications: Extensive experimental and DFT studies

Highly responsive and optically selective (E)-1-((4-phenoxyphenyl) diazenyl)naphthalen-2-ol) sensor PDN with aggregation induced emission enhancement (AIEE) properties has been developed for the sequential detection of Cu2+ and L- Cysteine through fluorescence On-Off-On strategy. The selectivity of sensor depends on the presence of a diazo functional group and its appropriate cavity location in sensor molecule. Azo dye-based (E)-1-((4-phenoxyphenyl) diazenyl)naphthalen-2-ol) sensor PDN has been synthesized by utilizing a simple diazotization synthetic methodology that showed extraordinary AIEE behavior with bathochromic shift owing to the formation of J-aggregates. The morphology and size of aggregates were analyzed by SEM and DLS analysis, respectively. The calculated LOD of sensor PDN for Cu2+, and L-cysteine is 0.113 nM, and 84 nM, respectively. Fluorescence, UV–visible, LC-MS, 1H and 13C NMR titration were carried out to understand the interaction of sensor with Cu2+. The sensor was practically utilized in the sequential sensing of Cu2+ and Cys in real samples. Interestingly, sensor PDN was successfully employed for the sensing of a strong acid and base as well as the detection of Cu2+ ions in the solid state. Moreover, these experimental results were supported through DFT calculations.

Visualizing the Structure and Dynamics of Transition Metal-Based Electrocatalysts Using Synchrotron X-Ray Absorption Spectroscopy.

As the global energy structure evolves and clean energy technologies advance, electrocatalysis has become a focal point as a critical conversion pathway in the new energy sector. Transitional metal electrocatalysts (TMEs) with their distinctive electronic structures and redox properties show great potential in electrocatalytic reactions. However, complex reaction mechanisms and kinetic limitations hinder the improvement of energy conversion efficiency, highlighting the necessity for comprehensive studies on structure and performance of electrocatalysts. X-ray Absorption Fine Structure (XAFS) spectra stand out as a robust tool for examining the electrocatalyst's structures and performance due to its atomic selectivity and sensitivity to local environments. This review delves into the application of XAFS technology in characterizing TMEs, providing in-depth analyses of X-ray Absorption Near-Edge Structure (XANES) spectra, and Extended XAFS (EXAFS) spectra in both R-space and k-space. These analyses reveal intrinsic structural information, electronic interactions, catalyst stability, and aggregation morphology. Furthermore, the paper examines advancements in in-situ XAFS techniques for real-time monitoring of active site changes, capturing critical intermediate and transitional states, and elucidating the evolution of active species during electrocatalytic reactions. These insights deepen our understanding on structure-activity relationship of electrocatalysts and offer valuable guidance for designing and developing highly active and stable electrocatalysts.

Physicochemical Properties and Metal Ion-Binding Capacity of Thermal-Induced Antarctic Krill Protein Aggregates under Different pH Conditions.

Protein properties can be modified by thermal treatment at different pH values, resulting in the formation of protein aggregates with diverse morphologies and functionalities. This study investigated the morphology of aggregates of Antarctic krill protein (AKPS) formed by thermal treatment (90 °C, 15 min) at pH 2, 3, 4, and 6-12, characterized the different morphologies of AKPS, and determined the metal ion (Ca2+, Fe2+, and Zn2+)-binding capacities. Results showed that heat treatment with different pH values generated various AKPS with distinct morphology and metal ion-binding abilities. AKPS have formed fibrils at pH ≤ 3, particles at pH 4-7, and amorphous aggregates at pH ≥ 8. Fibrous AKPS (pH 2) exhibited a high solubility (80.36%) and strong reducing effect on iron. The binding capacities of Ca2+ and Fe2+ reached 36.08% and 66.75%. Particulate AKPS (pH 6 and 7) primarily only showed Zn2+-binding capacity similar to that of casein phosphopeptide (17.33%). Amorphous AKPS (pH 9-11) displayed the optimal capacity to bind Zn2+ and Fe2+ (26.90% and 74.94%). The alterations in morphology and functional characteristics of AKPS permit the design of various nanostructures for food-derived mineral supplements, thus developing their potential for application in functional foods.

A stochastic particle model for aggregate morphology and particle size distributions under coagulation process

A new simple and efficient particle model is proposed in the present study based on the ballistic cluster–cluster agglomeration (BCCA) mechanism. The proposed Random Orientation-Tangent Point (ROTP-BCCA) model is implemented into the Monte Carlo method to investigate the aggregate coagulation process under the free molecular regime. The proposed ROTP-BCCA model is firstly used to predict the fractal characteristics of aggregates composed of monodispersed primary particles and validated by the previously reported results and is compared with the method of Lindberg et al. (L-BCCA model). Then the effects of primary particle polydispersity on the fractal characteristics, the first three order moments and the particle size distributions (PSD) of the aggregates are also investigated. The results show that the obtained fractal characteristics, the first three order moments and the particle size distributions of the aggregates for monodispersed and polydispersed primary particles from the present ROTP-BCCA model agree well with the results of L-BCCA model. Furthermore, the computational efficiency of the present proposed ROTP-BCCA model is proved to be much higher than the L-BCCA model.

1D, 3D supramolecular assemblies of a series of cyclometalated platinum(II) complexes with deep-red aggregation-induced phosphorescent emission and anion turn-on sensing via Pt-Pt interaction

Controlling the size and morphology of supramolecular assemblies is still an enormous challenge for the development of novel functional materials. Herein, cyclometalated platinum(II) complexes were designed and used as effective theragnostic supramolecular nano agents. Benzoquinoline was used as the main C^N ligand, and the increased number of aromatic rings in the N^N ligand of Pt complexes could greatly improve lipophilicity and cytotoxicity towards cancer cells over normal cells. Moreover, the morphology of nanoparticles formed by self-assembly of Pta-d could change from one to three-dimensional (1-3D), which can form nanowires and nanospheres. Besides, complexes of Pta-c, the number of aromatic rings in the N^N ligand of which does not exceed 4, all exhibit significant aggregation-induced phosphorescent emission (AIPE) with 100 - 200-fold enhancement in red phosphoresce intensity recorded in the solvent of Pta-1 and Ptb. Pt-Pt interaction induced by coordination and electrostatic interaction between complex and anions, and a new deep red emission improvement was observed in aqueous solution of Pta and Ptb with the presence of ClO4−, and two similar deep red emissions induced by two different interactions can be told by new emerging MMLCT absorption band. Ptd of dppz ligand exhibits the highest efficiency in inducing apoptosis of HeLa and its anticancer mechanism was studied. Our work aims to promote the fundamental comprehension of the self-assembly behavior of cyclometalated platinum complex with AIPE in vitro and living cells.

The combined role of hematocrit and shear flow on the morphology of platelet aggregates by Fast Fourier Transform and 4D confocal microscopy

The combined role of hematocrit and shear flow on the morphology of platelet aggregates by Fast Fourier Transform and 4D confocal microscopy

Investigations on the rheological properties of cement mortar based on fine aggregate characteristic and its extended prediction model

The rheological property of mortar is significantly influenced by its contained fine aggregate morphology characteristic and capable predictive models are limited. This work aims to expand the film thickness theory by developing an index that integrally represents variations in grain shape, gradation, and mix proportions, and elucidates the impact and the mechanism of these multifactorial differences on rheological performance. The quantitative analysis of the aggregate gradation and particle shape differences were performed, which was used to assess the impact of these variations and different mix ratios on the rheological performance of mortars. A correlation between aggregate differences and film thickness was established using specific surface area and void ratio. The result shows that variations in aggregates are accurately assessed by image analysis and consistently reflected in specific surface area and void ratio metrics. Since variations in rheological performance are predominantly governed by differences in film thickness, the disparities among aggregates can be quantified in terms of their impact on rheological properties by considering specific surface area and void ratio, thus translating into variations of film thickness. The differences in rheological properties due to variations in grain shape, gradation, and mix proportions can be comprehensively represented and controlled through an expansion of the film thickness model.

4,4'-Sulfonyldianiline Derived Aggregation-Induced Emission Luminogen for the Detection of Ofloxacin.

The excessive use of antibiotic ofloxacin (Oflx) can cause serious detrimental effects to human health. Therefore, the utmost research priority is required to develop facile methods to detect Oflx. Herein, a V-shaped aggregation-induced emission (AIE) active Schiff base SDANA was introduced for the fluorescent turn-on detection of Oflx. The Schiff base SDANA was synthesized by condensing 4,4'-sulfonyldianiline with two equivalents of 2-hydroxy-1-naphthaldehyde. The nearly non-fluorescent SDANA in DMSO showed strong orange emission with the increase in HEPES buffer (H2O, 10 mM, pH 7.4) fractions in DMSO from 70 %-95 % due to the combined effects of AIE and ESIPT. The DLS and SEM analyses were performed to complement the formation of self-aggregates of SDANA. With the addition of Oflx, the fluorescence emission of AIE luminogen (AIEgen) SDANA (λem=575 nm, λex=400 nm) was blue-shifted and enhanced at 530 nm. The interactions of Oflx over the surface of SDANA aggregates disrupted the intramolecular charge transfer and aggregation morphology of SDANA, which gave a distinct fluorescence response to detect Oflx. The detection limit for Oflx was estimated as 0.81 μM, and the developed probe AIEgen SDANA was applied for the quantification of Oflx in human blood serum.

Distinct Effects of SARS-CoV-2 Protein Segments on Structural Stability, Amyloidogenic Potential, and α-Synuclein Aggregation.

Amyloidosis is characterized by the abnormal accumulation of misfolded proteins, called amyloid fibrils, leading to diverse clinical manifestations. Recent studies on the amyloidogenesis of SARS-CoV-2 protein segments have raised concerns on their potential link to post-infection neurodegeneration, however, the mechanisms remain unclear. Herein, we investigated the structure, stability, and amyloidogenic propensity of a nine-residue segment (SK9) of the SARS-CoV-2 envelope protein and their impact on neuronal protein α-synuclein (αSyn) aggregation. Specifically, the amino acid sequence of the SK9 wildtype has been modified from a basic and positively charged peptide (SFYVYSRVK), to a nearly neutral and more hydrophobic peptide (SAAVASAVK, labelled as SK9 var1), and to an acidic and negatively charged peptide (SDAVANAVK, labelled as SK9 var2). Our findings reveal that the SK9 wildtype exhibited a pronounced amyloidogenic propensity due to its disordered and unstable nature, while the SK9 variants possessed more ordered and stable structures preventing the amyloid formation. Significantly, the SK9 wildtype demonstrated distinct effect on αSyn aggregation kinetics and aggregate morphology to facilitate the formation of αSyn aggregates with enhanced resistance against enzymatic degradation. This study highlights the potential of modifying short peptide sequences to fine-tune their properties, providing insights into understanding and regulating viral-induced amyloid aggregations.

Impact of Acidic and Alkaline Environments on the Surface Morphology of Biodentine and White Mineral Trioxide Aggregate - An In-vitro Study.

The physical and chemical properties of calcium silicate cement might be affected due to exposure to acidic or alkaline conditions during clinical use. The present study aimed to evaluate the effect of acidic and alkaline environments on the surface morphology of biodentine (BD) and white mineral trioxide aggregate (wMTA). Disc-shaped specimens of BD (n = 30) and wMTA (n = 30) were prepared in a metal mould and wrapped in pieces of gauze. They were divided into three sub-groups according to the storage media: group A, soaked in sterile distilled water at a pH of 7.0; group B, exposed to butyric acid buffered at pH 4.0; and group C, exposed to calcium hydroxide solution buffered at pH 12.0. The specimens were incubated for 7 days at 37°C, followed by examination under scanning electron microscopy at 1000x and 5000x magnification to characterise the microstructural morphology. Definite changes were seen in the microstructure of BD and wMTA on exposure to acidic and alkaline pH. The microstructure of wMTA tends to exhibit reduced cohesion when exposed to an acidic environment, especially when compared to an alkaline pH. Acidic pH exerts a milder influence on the morphological structure of BD when contrasted with its effects on wMTA. Biodentine may emerge as a more prudent choice than wMTA for utilisation in inflamed periapical regions.

Effects of Enhanced Phytoremediation Techniques on Soil Aggregate Structure

In response to the current serious problem of soil cadmium (Cd) contamination in agricultural land, phytoremediation technology is a green and environmentally friendly application prospect; however, its remediation efficiency is currently limited. An enhanced phytoremediation technique was constructed using the biodegradable chelator aspartate diethoxysuccinic acid (AES) combined with the plant growth regulator gibberellic acid (GA3) to enhance the formation of maize. This technique has been proven to have a superior remediation effect. However, the safety of the restoration technique is of particular importance. The remediation process not only removes the contaminants, but also ensures that the original structure and stability of the soil is not damaged. In this regard, the constructed enhanced phytoremediation technique was further investigated in this study using soil columns. In combination with microscopic tests, such as X-ray diffraction and scanning electron microscopy, this study investigated the effects of the remediation process on the distribution characteristics of Cd in soil aggregates, and the structure and stability of soil aggregates. This was conducted by analyzing, as follows: plant growth conditions; the morphology, structure and mineral composition of soil aggregates in different soil layers; and the changes in these characteristics. The results demonstrated that the enhanced phytoremediation technique constructed in this study has a negligible impact on the morphology and mineral composition of soil aggregates, while exerting a limited influence on soil structure stability. This indicates that the technique can facilitate the safe utilization of remediated contaminated soil.

Facile synthesis and mechanistic insights into ZSM-5 aggregates via a mesoporogen-free route

Developing hierarchical zeolites is highly important for catalytic applications. In this study, micro- and submicron-sized hierarchical ZSM-5 zeolites, composed of aggregated nanosized ZSM-5 crystals, were facilely synthesized without any mesoporogen. The effects of the gel composition in a mesoporogen-free system on the formation of ZSM-5 aggregates were studied. The results revealed that the Na2O/SiO2 molar ratio and the aluminum source exerted significant impacts. Furthermore, we demonstrated that the morphology and size of the ZSM-5 aggregate could be easily adjusted by varying the gel composition. Mechanistic insights indicated that the formation of hierarchical ZSM-5 aggregates in the mesoporogen-free system likely followed a space-confined growth mechanism.