Transmission Electron Microscopy Observations Research Articles

Thermal Stability and Crystallization Processes of Pd78Au4Si18 Thin Films Visualized via In Situ TEM.

Amorphous alloys or metallic glasses (MGs) thin films have attracted extensive attention in various fields due to their unique functional properties. Here, we use in situ heating transmission electron microscopy (TEM) to investigate the thermal stability and crystallization behavior of Pd-Au-Si thin films prepared by a pulsed laser deposition (PLD) method. Upon heating treatment inside a TEM, we trace the structural changes in the Pd-Au-Si thin films through directly recording high-resolution images and diffraction patterns at different temperatures. TEM observations reveal that the Pd-Au-Si thin films started to nucleate with small crystalline embryos uniformly distributed in the glassy matrix upon approaching the glass transition temperature Tg=625K, and subsequently, the growth of crystalline nuclei into sub-10 nm Pd-Si nanocrystals commenced. Upon further increasing the temperature to 673K, the thin films transformed to micro-sized patches of stacking-faulty lamellae that further crystallized into Pd9Si2 and Pd3Si intermetallic compounds. Interestingly, with prolonged thermal heating at elevated temperatures, the Pd9Si2 transformed to Pd3Si. Simultaneously, the solute Au atoms initially dissolved in glassy alloys and eventually precipitated out of the Pd9Si2 and Pd3Si intermetallics, forming nearly spherical Au nanocrystals. Our TEM results reveal the unique thermal stability and crystallization processes of the PLD-prepared Pd-Au-Si thin films as well as demonstrate a possibility of producing a large quantity of pure nanocrystals out of amorphous solids for various applications.

The Influence of Precipitated Particles on the Grain Size in Cold-Rolled Al-Mn Alloy Foils upon Annealing at 100-550 °C.

The Al-Mn alloy heat exchanger fin production process includes a brazing treatment at s high temperature of 600 °C, in which coarse grains are preferred for their high resistance to deformation at elevated temperatures by decreasing the grain boundary sliding. In this study, Al-1.57Mn-1.57Zn-0.58Si-0.17Fe alloy foils cold rolled by 81.7% (1.1 mm in thickness) and 96.5% (0.21 mm in thickness) were annealed at 100-550 °C for 1 h to investigate their recrystallization behavior, grain sizes, and precipitates by increasing the annealing temperature, using micro-hardness measurement, electron back-scattered diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The micro-hardness results showed that the recrystallization finishing temperatures for the two samples were almost the same, 323 ± 2 °C. The EBSD results showed that when the annealing temperature decreased from 550 to 400 °C, the recrystallized grain sizes of the two samples were nearly identical-both increased slightly. Further decreasing the annealing temperature from 400 to 330 °C caused the grain sizes to increase more, with the thinner foil sample having a more significant increase. The SEM and TEM observations showed that the micron-sized primary-phase remained unchanged during the annealing process. The nano-sized secondary phase precipitates formed during the hot-rolling process experienced a coarsening and dissolving process upon annealing. The particle size of the secondary phase increased from 32 nm to 44 nm and the area fraction decreased from 4.2% to 3.8%. The nucleation analysis confirmed that the large primary-phase could act as a nucleation site through particle stimulated nucleation (PSN) mode. The relatively dense secondary phase precipitates with small sizes at lower temperatures could provide higher Zener drag to the grain boundaries, leading to fewer nuclei and thereafter coarser grains. The coarsening of the recrystallized grains in the foils could be implemented through thickness reduction and/or precipitation processes to form densely distributed nano-sized precipitates.

Aptly chosen, effectively emphasizing the action and mechanism of antimycin A1.

Rhizoctonia solani Kühn, a plant pathogenic fungus that can cause diseases in multiple plant species is considered one of the common and destructive pathogens in many crops. This study investigated the action of antimycin A1, which was isolated from Streptomyces AHF-20 found in the rhizosphere soil of an ancient banyan tree, on Rhizoctonia solani and its mechanism. The inhibitory effect of antimycin A1 on R. solani was assessed using the comparative growth rate method. The results revealed that antimycin A1 exhibited a 92.55% inhibition rate against R. solani at a concentration of 26.66 μg/mL, with an EC50 value of 1.25 μg/mL. To observe the impact of antimycin A1 on mycelial morphology and ultrastructure, the fungal mycelium was treated with 6.66 μg/mL antimycin A1, and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed. SEM analysis demonstrated that antimycin A1 caused mycelial morphology to become stripped, rough, and folded. The mycelium experienced severe distortion and breakage, with incomplete or locally enlarged ends, shortened branches, and reduced numbers. TEM observation revealed thickened cell walls, indistinct organelle boundaries, swollen mitochondria, exosmotic substances in vesicles, slow vesicle fusion, and cavitation. Real-time quantitative PCR and enzyme activity assays were conducted to further investigate the impact of antimycin A1 on mitochondria. The physiological and biochemical results indicated that antimycin A1 inhibited complexes III and IV of the mitochondrial electron transport chain. RT-PCR analysis demonstrated that antimycin A1 controlled the synthesis of relevant enzymes by suppressing the transcription levels of ATP6, ATP8, COX3, QCR6, CytB, ND1, and ND3 genes in mitochondria. Additionally, a metabolomic analysis revealed that antimycin A1 significantly impacted 12 metabolic pathways. These pathways likely experienced alterations in their metabolite profiles due to the inhibitory effects of antimycin A1. Consequently, the findings of this research contribute to the potential development of novel fungicides.

Transcriptional and ultrastructural changes of macrophages after african swine fever virus infection

African swine fever (ASF) is a highly impactful infectious disease in the swine industry, leading to substantial economic losses globally. The causative agent, African swine fever virus (ASFV), possesses intricate pathogenesis, warranting further exploration. In this study, we investigated the impact of ASFV infection on host gene transcription and organelle changes through macrophage transcriptome sequencing and ultrastructural transmission electron microscopy observation. According to the results of the transcriptome sequencing, ASFV infection led to significant alterations in the gene expression pattern of porcine bone marrow derived macrophages (BMDMs), with 2404 genes showing upregulation and 1579 genes downregulation. Cytokines, and chemokines were significant changes in the expression of BMDMs; there was significant activation of pattern recognition receptors such as Toll-like receptors and Nod-like receptors. According to the observation of the ultrastructure, mitochondrial damage and mitochondrial autophagy were widely present in ASFV-infected cells. The reduced number of macrophage pseudopodia suggested that virus-induced structural changes may compromise pathogen recognition, phagocytosis, and signal communication in macrophages. Additionally, the decreased size and inhibited acidification of secondary lysosomes in macrophages implied suppressed phagocytosis. Overall, ASFV infection resulted in significant changes in the expression of cytokines and chemokines, accompanied by the activation of NLR and TLR signaling pathways. We reported for the first time that ASFV infection led to a reduction in pseudopodia numbers and a decrease in the size and acidification of secondary lysosomes.

Extraction of Nano Hydroxyapatite from Eggshell and Characterization for Biomedical Applications

Because of the exceptional qualities, nano-hydroxyapatites, or n-HA, are excellent materials for diverse applications. It is simple and convenient to synthesize from various natural ingredients. The synthesis of n-HA from eggshells, a typical domestic waste product in the neighborhood, was the primary goal of this study project. This synthesis of n-HA was performed using ammonia and orthophosphoric acid as chemical reagents. The synthesized n-HA have been characterized by UV (Ultraviolet), FTIR (Fourier Transformed Infrared Spectroscopy), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and XRD (X-ray diffraction) analysis. The peak formed by the UV analysis verified the successful formation of n-HA in the solution. The bandgap has been determined through additional research on the UV data. The SEM and TEM images show the size and form of the synthesized n-HA. Based on TEM observations, the synthesized n-HA has a size in the range of 10 to 40 nm. The peak ensures the n-HA’s crystallinity that the XRD analysis produced. The obtained crystallinity was 74%.

Isolation and characteristic of Bacillus cereus phage Z3 and its application in rice and milk

Bacillus cereus is a foodborne pathogen that widely exists in various food products. In this study, a new B. cereus phage, named Z3, was isolated from the soil and characterized. Transmission electron microscopy (TEM) observations revealed that Z3 had an icosahedral head and a retractable tail, belonging to myxovirus. The double-stranded linear DNA of Z3 was 159,116 bp in length with a CG% content of 39.96%. Genomic analysis indicated that Z3 represented a new species belonging to the Caeruleovirus genus. Z3 showed broad lytic spectrum, as it could lyse 10 out of 13 tested strains of B. cereus. The in vitro phage killing assay and the one-step growth curve showed that Z3 could effectively inhibit the bacteria growth within 10 h and it had a short latent period and fast multiplication speed. Besides, stability tests showed that Z3 was tolerant to a wide range of temperature (4 °C–55 °C) and pH levels (4–10), and was UV-resistant for 100 min. Furthermore, the applications of Z3 in rice and milk demonstrated its effective antimicrobial properties against B. cereus in food matrix. These findings suggested that Z3 may be a promising biocontrol agent against B. cereus in food industry.

Real-Time TEM Observation of the Role of Defects on Nickel Silicide Propagation in Silicon Nanowires.

Metal silicides have received significant attention due to their high process compatibility, low resistivity, and structural stability. In nanowire (NW) form, they have been widely prepared using metal diffusion into preformed Si NWs, enabling compositionally controlled high-quality metal silicide nanostructures. However, unlocking the full potential of metal silicide NWs for next-generation nanodevices requires an increased level of mechanistic understanding of this diffusion-driven transformation. Herein, using in situ transmission electron microscopy (TEM), we investigated the defect-controlled silicide formation dynamics in one-dimensional NWs. A solution-based synthetic route was developed to form Si NWs anchored to Ni NW stems as an optimal platform for in situ TEM studies of metal silicide formation. Multiple in situ annealing experiments led to Ni diffusion from the Ni NW stem into the Si NW, forming a nickel silicide. We observed the dynamics of Ni propagation in straight and kinked Si NWs, with some regions of the NWs acting as Ni sinks. In NWs with high defect distribution, we obtained direct evidence of nonuniform Ni diffusion and silicide retardation. The findings of this study provide insights into metal diffusion and silicide formation in complex NW structures, which are crucial from fundamental and application perspectives.

Double Z-scheme Ag2CrO4/Bi2O3–KBi6O9Br nanophotocatalysts designed via microwave-assisted combustion-precipitation method for degrading toxic organic dyes

This study introduces novel double Z-scheme Ag2CrO4/Bi2O3–KBi6O9Br nanophotocatalysts for effectively degrading organic dyes, namely Crystal Violet, Acid Orange 7, Rhodamine B, and Eosin Y, from contaminated wastewater. The photocatalysts were thoroughly characterized using advanced techniques, including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX-Dot Mapping), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), Diffuse Reflectance Spectroscopy (DRS), and Photoluminescence (PL). XRD confirmed the formation of desired crystalline phases without impurities. FESEM and TEM observations revealed the unique morphology of Bi2O3–KBi6O9Br, with distributed Ag2CrO4 nanoparticles on the surface, as confirmed by EDX-dot mapping. BET-BJH analyses indicated a specific surface area of 7.33 m2/g, including meso and macro pores with an average diameter of 10 nm and a total pore volume of 0.018 cm3/g for Ag2CrO4(25%)/Bi2O3–KBi6O9Br sample. DRS revealed notable shifts in absorption edges, suggesting the formation of a heterojunction, and PL analysis indicated a reduced charge carrier recombination rate, further enhancing the photocatalyst's efficacy. In a series of photocatalytic experiments lasting 240 min, using 1 g/L of Ag2CrO4(25%)/Bi2O3–KBi6O9Br, remarkable degradation efficiencies of 95.1%, 94.2%, 98.0%, and 89.6% were achieved for Crystal Violet, Acid Orange 7, Rhodamine B, and Eosin Y, respectively, at an initial concentration of 10 mg/L. The nanophotocatalyst also showed favourable stability after five consecutive reuses. Overall, the double Z-scheme heterostructure in the composite significantly improved the sample's properties and photocatalytic performance, making it highly effective in removing various organic dyes from wastewater.

Protective Effects of Hesperetin on Cardiomyocyte Integrity and Cytoskeletal Stability in a Murine Model of Epirubicin-Induced Cardiotoxicity: A Histopathological Study

Anthracyclines, including epirubicin (Epi), are effective chemotherapeutics but are known for their cardiotoxic side effects, primarily inducing cardiomyocyte apoptosis. This study investigates the protective role of hesperetin (HSP) against cardiomyopathy triggered by Epi in a murine model. Male CD1 mice were divided into four groups, with the Epi group receiving a cumulative dose of 12 mg/kg intraperitoneally, reflecting a clinically relevant dosage. The co-treatment group received 100 mg/kg of HSP daily for 13 days. After the treatment period, mice were euthanized, and heart tissues were collected for histopathological, immunofluorescence/immunohistochemistry, and transmission electron microscopy (TEM) analyses. Histologically, Epi treatment led to cytoplasmic vacuolization, myofibril loss, and fiber disarray, while co-treatment with HSP preserved cardiac structure. Immunofluorescent analysis of Bcl-2 family proteins revealed Epi-induced upregulation of the pro-apoptotic protein Bax and a decrease in anti-apoptotic Bcl-2, which HSP treatment reversed. TEM observations confirmed the preservation of mitochondrial ultrastructure with HSP treatment. Moreover, in situ detection of DNA fragmentation highlighted a decrease in apoptotic nuclei with HSP treatment. In conclusion, HSP demonstrates a protective effect against Epi-induced cardiac injury and apoptosis, suggesting its potential as an adjunctive therapy in anthracycline-induced cardiomyopathy. Further studies, including chronic cardiotoxicity models and clinical trials, are warranted to optimize its therapeutic application in Epi-related cardiac dysfunction.

Mechanistic understanding of enhanced thermal stability of twinned copper nanowires

Thermal instability problems of nanostructured materials, including grain coarsening and recrystallization, can be alleviated by introducing nanoscale coherent twin boundary (CTB) structures. However, the detailed interaction mechanism between CTB and grain boundaries (GBs) during microstructural transformation has not been well elucidated. To gain insight, we investigate the migration behavior of CTB-intercepted GBs in twinned copper nanowires at elevated temperatures through transmission electron microscopic observations and molecular dynamics simulations. The results show that numerous partial dislocations are conveyed to the CTB-intercepted GB through the densely distributed CTBs and further transferred to the nanowire surface along the GB. The growth of the twinned region along the diminishing GB is driven by minimizing the excess energy stored in dislocation defects and GBs. This CTB-mediated GB migration in twinned copper nanowires can be deactivated by surface passivation. This study will help to elucidate how the thermal stability of nanostructured metals is influenced by the twin structure and surface passivation.

Formation and evolution of secondary phases and surface altered layers during borosilicate glass corrosion in pore water

The emergent secondary phases and surface altered layer (SAL) during the aqueous corrosion of borosilicate glass have a great impact on its chemical durability. However, the formation and evolution of these structures are still unclear. Here, by studying the borosilicate glass altered at 90 °C in pore water, the water in pore space between glass powders, the formation of secondary phases could follow two ways: 1. the consumption of aqueous ions forms analcime, zeolite, calcium silicate and barite at the surface of glass; 2. the reorganization of silica aggregates leads to smectite within the SAL. Small-angle X-ray scattering and cross-sectional scanning electron microscopy results show that the release of soluble elements and the formation of smectite within the SAL significantly increase the porosity of SAL. Furthermore, the layer containing smectite reorganizes inwardly and the crystallinity of smectite is gradually increased over time. The observations of transmission electron microscopy reveal that the dissolution of glass potentially goes through an interface-coupled dissolution-reprecipitation process.

Peculiar martensitic microstructure and dislocation accumulation behavior in Ti-Ni-Cu shape memory alloys almost satisfying the triplet condition

Dislocation accumulation behavior at the lattice correspondence variant (CV) triplets of the Ti-Ni-Cu alloy close to the triplet condition (TC) was investigated by using in situ heating transmission electron microscopy observation. The martensitic microstructure of this alloy was peculiar because of no {011}o compound twin laminate as predicted by the phenomenological theory of martensite crystallography. The peculiar martensitic microstructure was composed of a combination of six different CVs connected by twin-relationship, including triplet and quadruple. Other types of triplets with higher incompatibility were not observed. It was revealed that few transformation-induced dislocations associated with thermal cycling were formed at the compatible martensitic microstructure satisfying the TC in the present alloy. The fact that few transformation-induced dislocations are formed in the TC microstructure in the Ti-30Ni-20Cu alloy during thermal cycling explains the good thermal cycling properties of this alloy.

Precipitation behavior of a new Cu-Ni-Co-Si-Fe-Mg alloy designed with low cobalt content

A new Cu-1.5Ni-0.7Co-0.7Si-0.3Fe-0.1Mg alloy with low cobalt content was designed. Multi-stage thermo-mechanical treatment (MTT) was used to produce the high-performance alloy with hardness of 286 HV, yield strength of 858 MPa, tensile strength of 910 MPa and electrical conductivity of 45.4 % IACS. The addition of 0.3 wt% Fe element dissolved in (Ni,Co)2Si resulted in the formation of the orthorhombic δ-(Ni,Co,Fe)2Si. During MTT, the δ-(Ni,Co,Fe)2Si, (Ni,Co)2Si, β-Ni3Si, and Fe2Si precipitated successively near the deformation microstructure. Transmission electron microscope observations indicated that the δ-(Ni,Co,Fe)2Si precipitates showed disc-like and rod-like shapes at different orientations, respectively. A new resource-saving, high-strength and medium-conductivity Cu-Ni-Co-Si-Fe-Mg alloy was prepared by replacing an equal amount of Co element with 0.3 wt% Fe element, reducing the amount of scarce metal Co in the alloy.

Pressure-induced ferroelectric and electronic transitions in two-dimensional ferroelectric semiconductor of NbOCl2 up to 41.7 GPa

NbOCl2, a representative van der Waals ferroelectric (FE) semiconductor, has become the research frontier due to its peculiar appeal in both fundamental research studies and potential applications. In the present work, the high-pressure structural, vibrational, and electrical transport properties of NbOCl2 under different hydrostatic environments were systematically investigated over a wide pressure range of 1.7–41.7 GPa using a diamond anvil cell coupled with in situ Raman spectroscopy, electrical conductivity, and high-resolution transmission electron microscopy (HRTEM) observations. Upon non-hydrostatic compression, NbOCl2 underwent a FE-to-antiferroelectric phase transition at 3.4 GPa, followed by a semiconductor-to-metal transformation at 15.7 GPa. Under hydrostatic compression, the FE transformation and metallization of NbOCl2 were postponed by ∼2.0 and ∼4.0 GPa due to the effect of helium pressure-transmitting medium. Upon decompression, the phase transition was demonstrated to be reversible under different hydrostatic environments, which was well corroborated by HRTEM analyses. In addition, the linear relations between electrical current and sinusoidal voltage with the nonlinearity factors of ∼1.0 reflect the Ohmic response of NbOCl2 before and after the FE transition. Our findings on NbOCl2 provide a guideline for exploring other layered FE materials under high pressure and establishing a design paradigm for new generations of FE-based devices.

Investigations into the antimicrobial behavior and cytotoxicity of purified detonation diamond nanoparticles and their assembled micro‐/nano‐structured films

Antimicrobial activity and cytotoxicity are significantly influenced by the type of carbon-based nanomaterials. To reveal the cellular behaviors of zero-dimensional (0D) diamond nanoparticles and their derivatives, the self-assembly technology was used to synthesize 2D micro‐/nano‐structured diamond film from single particles. The focused ion beam (FIB) lift-out method was conducted for Transmission Electron Microscopy (TEM) observation. This paper reported the antimicrobial performance of diamond nanoparticles and assembled diamond film against Gram-positive Bacillus sp. and Gram-negative E. coli as elucidated by characterizing the material-bacterial interaction behaviors. Diamond nanoparticle uptake by cells was visualized using TEM. Further biological testing of assembled micro‐/nano‐structured diamond films revealed the desirable biocompatibility and excellent anti-fouling performance against microbial adhesion and colonization. The presented results may contribute to the development of the manufacturing techniques and biological applications for micro‐/nano‐structured diamond films.

A study on functionalization process of silicon dioxide nanoparticles for hydrophobic coating applications

Functionalized nano‐SiO2 is an inorganic compound that exhibits hydrophobic properties upon the addition of a silane group through a chemical reaction. This property is highly effective in surface modification for various substrates, including glass, metal, and ceramics. These surface modifications find applications in self‐cleaning, anti‐fogging coatings, and water‐repellent materials. In this work, the role of nano‐SiO2 and Hexadecyltrimethoxysilane (HDTMS) functionalized nano‐SiO2 has been synthesized successfully by the sol–gel method for coating applications. The outcomes of water contact angle (WCA), analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), and transmission electron microscope (TEM) observations revealed the successful grafting of hydrophobic long‐chain alkyl groups from HDTMS onto the surface of SiO2 nanoparticles. Notably, when the ratio of SiO2 nanoparticles to HDTMS is 0.25:1, the WCA of the functionalized SiO2 nanoparticles is enhanced significantly. This value is 5.35 times greater than the initial angle of contact before the modification, leading to the achievement of a super hydrophobic property.

Comparative analysis of effects of conditioned mediums obtained from 2D or 3D cultured mesenchymal stem cells on kidney functions of diabetic rats: Early intervention could potentiate transdifferentiation of parietal epithelial cell into podocyte precursors

AimThe secretome of mesenchymal stem cells (MSCs) could be a potential therapeutic intervention for diabetes and associated complications like nephropathy. This study aims to evaluate the effects of conditioned mediums (CMs) collected from umbilical cord-derived MSCs incubated under 2-dimensional (2D) or 3D culture conditions on kidney functions of rats with type-I diabetes (T1D). Main methodsSprague-Dawley rats were treated with 20 mg/kg streptozocin for 5 consecutive days to induce T1D, and 12 doses of CMs were applied intraperitoneally for 4 weeks. The therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological, and immunohistochemical analysis. Key findings3D-CM had significantly higher total protein concentration than the 2D-CM Albumin/creatinine ratios of both treatment groups were significantly improved in comparison to diabetes. Light microscopic evaluations showed that glomerular and cortical tubular damages were significantly ameliorated in only the 3D-CM applied group compared to the diabetes group, which were correlated with transmission electron microscopic observations. The nephrin and synaptopodin expressions increased in both treatment groups compared to diabetes. The WT1, Ki-67, and active caspase-3 expressions in glomeruli and parietal layers of the treatment groups suggest that both types of CMs suppress apoptosis and promote possible parietal epithelial cells' (PECs') transdifferentiation towards podocyte precursor cells by switching on WT1 expression in parietal layer rather than inducing new cell proliferation. Significance3D-CM was found to be more effective in improving kidney functions than 2D-CM by ameliorating glomerular damage through the possible mechanism of transdifferentiation of PECs into podocyte precursors and suppressing glomerular apoptosis.

Sonochemical synthesis of SnS and SnS2 quantum dots from aqueous solutions, and their photo- and sonocatalytic activity

Our study reports the ultrasound-assisted synthesis of SnS and SnS2 in the form of nanoparticles using aqueous solutions of respective tin chloride and thioacetamide varying sonication time. The presence of both compounds is confirmed by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, as well as Raman and FT-IR spectroscopic techniques. The existence of nanoparticles is proven by powder X-ray diffraction investigation and by high resolution transmission electron microscopy observations. The size of nanocrystallites are in the range of 3–8 nm and 30 50 nm for SnS, and 1.5–10 nm for SnS2. X-ray photoelectron spectroscopy measurements, used to investigate the chemical state of tin and sulphur atoms on the surface of nanoparticles, reveal that they are typically covered with tin on the same oxidation degree as respective bulk compound. Values of optical bandgaps of synthesized nanoparticles, according to the Tauc method, were 2.31, 1.47 and 1.05 eV for SnS (60, 90 and 120 min long synthesis, respectively), and 2.81, 2.78 and 2.70 eV for SnS2 (60, 90 and 120 min long synthesis, respectively). Obtained nanoparticles were utilized as photo- and sonocatalysts in the process of degradation of model azo-dye molecules by UV-C light or ultrasound. Quantum dots of SnS2 obtained under sonication lasting 120 min were the best photocatalyst (66.9 % color removal), while quantum dots of SnS obtained under similar sonication time were the best sonocatalyst (85.2 % color removal).

Bacillus velezensis LT1: a potential biocontrol agent for southern blight on Coptis chinensis.

Southern blight, caused by Sclerotium rolfsii, poses a serious threat to the cultivation of Coptis chinensis, a plant with significant medicinal value. The overreliance on fungicides for controlling this pathogen has led to environmental concerns and resistance issues. There is an urgent need for alternative, sustainable disease management strategies. In this study, Bacillus velezensis LT1 was isolated from the rhizosphere soil of diseased C. chinensis plants. Its biocontrol efficacy against S. rolfsii LC1 was evaluated through a confrontation assay. The antimicrobial lipopeptides in the fermentation liquid of B. velezensis LT1 were identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS). The effects of B. velezensis LT1 on the mycelial morphology of S. rolfsii LC1 were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The confrontation assay indicated that B. velezensis LT1 significantly inhibited the growth of S. rolfsii LC1, with an inhibition efficiency of 78.41%. MALDI-TOF-MS analysis detected the presence of bacillomycin, surfactin, iturin, and fengycin in the fermentation liquid, all known for their antifungal properties. SEM and TEM observations revealed that the mycelial and cellular structures of S. rolfsii LC1 were markedly distorted when exposed to B. velezensis LT1. The findings demonstrate that B. velezensis LT1 has considerable potential as a biocontrol agent against S. rolfsii LC1. The identified lipopeptides likely contribute to the antifungal activity, and the morphological damage to S. rolfsii LC1 suggests a mechanism of action. This study underscores the importance of exploring microbial biocontrol agents as a sustainable alternative to chemical fungicides in the management of plant diseases. Further research into the genetic and functional aspects of B. velezensis LT1 could provide deeper insights into its biocontrol mechanisms and facilitate its application in agriculture.

A new method for preparation of RE2(CO3)3 by multi-membrane electroconversion

Preparing rare earth carbonates from rare earth chlorides is a common step in the smelting process for all rare earth ores; however, it produces large amounts of ammoniacal nitrogen wastewater and a chloride-rich precipitate. This study proposes a novel, green and simple process for preparing low-chlorine lanthanum carbonate via a multi-membrane electroconversion approach. The effects of the CO2 flow rate, current density, lanthanum chloride concentration, and electroconversion time on the electroconversion process were systematically explored. Under the optimal process conditions (CO2 flow rate = 0.5 L/min, current density = 25 mA/cm2, LaCl3 concentration = 0.3 mol/L, electroconversion time = 60 min), a current efficiency of 75.77% was obtained, along with a unit energy consumption of 5.44 kW h/kg. X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and laser particle size analysis results indicate that a pure La2(CO3)3·8H2O product is obtained with a median particle size of 6.53 μm and chlorine content of 0.0021%. In addition, scanning electron microscopy and transmission electron microscopy observations indicate that the crystallisation and growth of La2(CO3)3·8H2O conform to the oriented attachment and Ostwald ripening mechanisms. Thus, the proposed multi-membrane electroconversion method provides guidance toward the clean transformation of rare earth chlorides to low-chlorine lanthanum carbonates.