Transmission Electron Microscopy Analysis Research Articles

Facile microwave-assisted green synthesis and characterization of flower shaped zinc oxide nanoclusters using Centella asiatica (Linn.) leaf extract and evaluation of its antimicrobial activity and in vivo toxic effects on Artemia nauplii.

Green synthesized nanomaterials play a vital role in nanotechnology was due toits diverse applications. In the current study, flower shaped nanoclusters of zinc oxide nanoparticles (ZnONPs) was fabricated using the leaf extract of Centella asiatica (Linn.) by microwave-assisted method. The physico-chemical characterization of the green synthesized ZnONPs were further conducted by the UV-Vis spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy analysis. The UV-Vis spectrum of the synthesized ZnONPs has showedcharacteristic absorption maximum at 363 nm. The XRD pattern of the same could confirm to have the crystalline nature of ZnONPs. Additionally, the FT-IR spectra have revealed the presence of characteristic stretching and bending vibrations of the Zn-O bond, along with those of phytochemicals that might have involvedin ZnONPs stabilization. By the HR-TEM imaging, agglomeration of the nanoparticles and thereby the formation of flower-like clusters could be observed. Furthermore, the synthesized ZnONPs have remarkable antimicrobial activity against S. aureus and E. coli with inhibition zones of 15 ± 0.4 and 16.5 ± 1.0 mm respectively. The green synthesized ZnONPs showed no significant toxicity toward Artemianauplii. Hence, the results of the study indicate the promising potential of the synthesized ZnO nanoclusters.

A novel high-throughput screen identifies phenazine-1-carboxylic acid as an inhibitor of African swine fever virus replication in primary porcine alveolar macrophages

African swine fever (ASF), caused by African swine fever virus (ASFV), has resulted in significant economic impacts on the global swine industry. Currently, there is no safe and effective commercial vaccine available for ASFV. Thus, the development of effective and readily available therapeutics for ASF is urgently needed. To conduct high-throughput screening (HTS) for anti-ASFV drugs, we initially developed a recombinant dual-reporter virus (rASFV-Gluc/EGFP) using the virulent strain ASFV HLJ/18 (ASFV-WT). The enhanced green fluorescent protein (EGFP)- and Gaussia luciferase (Gluc)-encoding genes were incorporated downstream of the ASFV MGF300-4L gene without disrupting viral genes. The growth kinetics, hemadsorption, and transmission electron microscopy analysis of rASFV-Gluc/EGFP in primary porcine alveolar macrophages (PAMs) revealed that rASFV-Gluc/EGFP exhibits similar biological characteristics to ASFV-WT. Furthermore, analysis of Gluc activities, fluorescence, and next-generation sequencing indicated that rASFV-Gluc/EGFP maintains good genetic stability after 20 consecutive passages in PAMs. Using the HTS platform established with rASFV-Gluc/EGFP, we screened and identified phenazine-1-carboxylic acid (PCA) as an effective inhibitor of ASFV replication from 246 small molecule compounds in PAMs. Importantly, PCA was found to reduce ASFV replication by as much as 100-fold at a concentration of 25 μM. Overall, this study suggests that rASFV-Gluc/EGFP is suitable for rapid screening of anti-ASFV drugs. Importantly, we showed that PCA has significant anti-ASFV activity in PAMs.

Vitrification affects the post-implantation development of mouse embryos by inducing DNA damage and epigenetic modifications

Vitrification is widely used in assisted reproductive technology (ART) for female infertility, but the long-term effect on the embryo of vitrification has not been comprehensively studied. The study aimed to investigate the effect of vitrification on long-term development of mouse embryos. The warmed embryos which were frozen at 8-cell stage were cultured in vitro until the blastocyst stage and were transferred into recipients. Immunofluorescence staining was performed to evaluate the reactive oxygen species (ROS) level, mitochondrial function, cell apoptosis, DNA damage and histone epigenetic modification in blastocysts. Transmission electron microscopy (TEM) analysis was performed to exam the mitochondrial ultrastructure in blastocysts. The related gene expression and transcriptome profiles were investigated by RT-qPCR and RNA-seq, respectively. Blastocyst and implantation frequencies were not significantly affected by vitrification. However, vitrification significantly reduced blastocyst cell number and the live pup frequency. Vitrification induced ROS accumulation, DNA damage, and apoptosis in mouse blastocysts. The homologous recombination (NHEJ) is the major DNA repair pathway for vitrified embryos. Vitrification elevated H3K4me2/3, H4K12ac, and H4K16ac levels and reduced m6A modification in blastocysts. Moreover, vitrification significantly altered transcriptome profiles of mice placentas and brains at embryonic day 18.5 (E18.5). Thus, vitrification exhibited a long-term effect on mouse embryo viability by increasing ROS levels, DNA damage, altering the epigenetic modifications and transcriptome profiles.

Green synthesis of Ag-Pd bimetallic nanoparticles and its efficacy against mosquito larvae and non-target organisms

BackgroundEmerging studies on bimetallic nanoparticles highlight their unique synergistic properties, but their efficacy and toxicity require further validation. Silver-palladium bimetallic nanoparticles (Ag-Pd BNPs), synthesized via eco-friendly biological methods, have demonstrated potential applications in catalysis, sensing, antimicrobial activities etc. However, data on their toxicity against invertebrates remains limited. The current study addresses this gap by presenting the eco-friendly synthesis of Ag-Pd BNPs using a nontoxic aqueous leaf extract of the plant Citrus limon. The synthesized nanoparticles were characterized using various techniques, and their efficacy was evaluated against mosquito larvae and nymphs of damselfly and dragonfly.ResultsUV–Vis spectroscopy analysis showed maximum absorption at 300 nm ± 40 nm for the leaf extract, while for Ag-Pd BNPs an absence of a surface plasmon resonance band was observed. FT-IR spectroscopy analysis revealed the involvement of surface functional groups from the leaf extract in nanoparticle synthesis. TEM analysis determined a mean particle size of 21 ± 7 d nm. DLS analysis showed an overall hydrodynamic size of the nanoparticles clusters with a Z-average of 1956 d nm. SEM–EDX analysis verified the presence and purity of the Ag-Pd BNPs in the sample, and XRD results identified the leaf extract-mediated synthesis with distinct peaks obtained for Ag and Pd. The nano-toxicity efficacy of Ag-Pd BNPs revealed significant larval mortality against I, II, III, and IV instar larvae of both Anopheles stephensi and Aedes aegypti mosquito species, at 24 h, 48 h, and 72 h of exposure. The selected LC50 was further selected to study the predation efficiency of the non-target nymphs of damselfly and dragonfly which revealed time-dependent predation dynamics, resulting in high predation rates over specific time intervals.ConclusionThe present study offers significant scientific insights into an eco-friendly synthesis and characterization of Ag-Pd BNPs. Their inherent toxic ability to cause mortality in invertebrates like mosquito larvae underscores the need for caution in their environmental application. However, the absence of mortality among the odonate nymphs suggests the potential use of Ag-Pd BNPs in integrated vector management with optimized concentration. Future research can focus on developing controlled-release formulations to optimize environmental safety and facilitate easier remediation in natural ecosystems.

Multiple mechanisms of action of a triazole-derived salt against Leishmania amazonensis: apoptosis-like death and autophagy.

Current chemotherapy for leishmaniasis faces significant limitations due to high toxicity, prolonged treatment regimens, and increasing parasite resistance, highlighting the urgent need for innovative treatment strategies. This study aimed to evaluate the in vitro activity of 1,2,3-triazole derivatives against promastigotes and amastigotes of Leishmania amazonensis, as well as their cytotoxicity in murine macrophages. Additionally, we investigated the mechanism of parasite death through different biochemical and cellular indicators of cell death parameters. Our results underscored the importance of the salt form, as the neutral form showed no inhibition of parasite growth. In contrast, the triazole-derived salt demonstrated promising selective index (SI = 34.28) and antileishmanial activity (IC50 = 0.13 μM and IC50 = 2.06 μM against promastigote and amastigote forms, respectively), proving more active than miltefosine, the standard drug. Regarding the mode of action of the triazole-derived salt, this compound induced significant mitochondrial alterations in the parasite, characterized by an increase in mitochondrial membrane potential (ΔΨm), elevated levels of total and mitochondrial Reactive Oxygen Species (ROS), and lipid body accumulation in the cytoplasm. Treatment with triazole-derived salt also produced several ultrastructural, biochemical, and cellular changes in the promastigote forms, such as the occurrence of apoptosis-like death, including cell shrinkage and reduction in length, as well as exposure of phosphatidylserine in the outer leaflet of the plasma membrane and marked cell cycle interruption, in addition to DNA fragmentation. Despite MDC positive and the presence of membrane-bound vacuoles resembling autophagosomal structures observed by TEM analysis, autophagy is not a predominant process, with severe mitochondrial damage emerging as the primary event leading to parasite death. These findings demonstrate the promising antileishmanial potential of the triazole-derived salt, with its effect on multiple targets in parasite cells. Moreover, the association of the active compound with miltefosine showed an additive effect in treating L. amazonensis-infected macrophages. Altogether, these results highlight the therapeutic potential of the evaluated salt and support further studies to assess its in vivo efficacy in a murine model of cutaneous leishmaniasis.

Bioharvesting and improvement of nano-silica yield from bagasse by irradiated Curvularia spicifera

BackgroundSugarcane bagasse is an organic waste material abundant in silica. Silica is a very significant inorganic substance that is widely employed in a variety of industrial applications.This study displays an eco-friendly and inexpensive biotransformation process producing silica nanoparticles (SNPs) using a primarily reported Curvularias picifera strain under solid-state fermentation (SSF) on bagasse as a starting material. The produced SNps were characterized by XRD, DLS, Zeta sizer, FT-IR, SEM, and TEM analyses. The silica bioleaching ability of C. spicifera was further amended by exposure to gamma irradiation at a dose of 750 Gy. The biotransformation process was additionally optimized by applying response surface methodology (RSM).ResultAccording to screening experiments, the selected promising fungal isolate was identified as Curvularia spicifera AUMC 15532. The SNPs fabrication was significantly enhanced by gamma irradiation (optimal dose 750 Gy) and response surface methodology for the first time. The attained SNps’ size ranged from 30.6–130.4 nm depending on the biotransformation conditions employed in the statistical model, which is available for numerous applications. The XRD shows the amorphous nature of the fabricated SNPs, whereas the FTIR analysis revealed the three characteristic bands of SNPs. The outcomes of the response surface optimization demonstrated that the model exhibited an adequate degree of precision, as evidenced by the higher R2 value (0.9511) and adjusted R2 value (0.8940), which confirmed the model’s close correspondence with the experimental data. A gamma irradiation dose of 750 Gy was optimal for a significant increase in the silica bioleaching activity by C. spicifera fermented bagasse (71.4% increase compared to the non-irradiated strain).

Microstructure Evolution of Rapid Solidified Invar Alloy

Invar alloy has a wide range of applications in aerospace and precision instruments. However, the microstructure evolution during rapid solidification is not yet fully understood. In this study, the rapid solidification microstructure of Invar alloy with undercooling ranging from 5 K to 231 K was investigated using optical microscopy, EBSD, and TEM techniques. The results show that, as the undercooling increased from 5 K to 181 K, the microstructure transitioned from large dendrites to columnar grains and finally to small equiaxed grains. When the undercooling ranged from 181 K to 193 K, the grain size suddenly increased before continuing to decrease with further undercooling. EBSD analysis revealed that, for ΔT > 181 K, two distinct types of grains appeared in the microstructure: one larger and the other much smaller. Under low undercooling conditions, the grains grew anisotropically with a preferred orientation, while under high undercooling, there was no apparent preferred growth orientation. Many twin boundaries were observed in the high-undercooling samples, which were further confirmed by TEM analysis. Additionally, both twin boundaries and high-angle grain boundaries increased gradually with undercooling.

Neural progenitor cell-derived exosomes in ischemia/reperfusion injury in cardiomyoblasts.

The physiologic relationship between the brain and heart is emerging as a novel therapeutic target for clinical intervention for acute myocardial infarction. In the adult human brain, vestigial neuronal progenitor stem cells contribute to neuronal repair and recovery following cerebral ischemic injury, an effect modulated by secreted exosomes. Ischemia conditioned neuronal cell derived supernatant and experimental stroke has been shown to be injurious to the heart. However, whether unconditioned neuronal progenitor cell derived-exosomes can instead protect myocardium represents a profound research gap. We investigated the effects of unconditioned neural stem cell derived exosomes as post-injury treatment for cardiomyoblasts from three neuronal culture conditions; adherent cultures, neurosphere cultures and bioreactor cultures. Small extracellular vesicles were enriched with serial ultracentrifugation, validated via nanoparticle tracking analysis, transmission electron microscopy and Western blot analysis prior to utilization as post-injury treatment for H9c2 cardiomyoblasts following oxygen and glucose deprivation. LDH assay was used to assess viability and Seahorse XF high-resolution respirometry analyzer to investigate post-injury cardiomyocyte bioenergetics. We found no evidence that unconditioned neural stem cell derived exosomes are cardiotoxic nor cardioprotective to H9c2 cardiomyoblasts following ischemia-reperfusion injury. Based on our findings, utilizing unconditioned neural stem cell derived exosomes as post-injury treatment for other organs should not have adverse effects to the damaged cardiac cells.

Long-term excessive alcohol consumption enhances myelination in the mouse nucleus accumbens.

Chronic excessive alcohol (ethanol) consumption induces neuroadaptations in the brain's reward system, including biochemical and structural abnormalities in white matter that are implicated in addiction phenotypes. Here, we demonstrate that long-term (12-week) voluntary ethanol consumption enhances myelination in the nucleus accumbens (NAc) of female and male adult mice, as evidenced by molecular, ultrastructural, and cellular alterations. Specifically, transmission electron microscopy analysis showed increased myelin thickness in the NAc following long-term ethanol consumption, while axon diameter remained unaffected. These changes were paralleled by increased mRNA transcript levels of key transcription factors essential for oligodendrocyte differentiation, along with elevated expression of critical myelination-related genes. In addition, diffusion tensor imaging (DTI) revealed increased connectivity between the NAc and the prefrontal cortex (PFC), reflected by a higher number of tracts connecting these regions. We also observed ethanol-induced effects on oligodendrocyte (OL) lineage cells, with a reduction in the number of mature OLs (mOLs) after 3 weeks of ethanol consumption, followed by an increase after 6 weeks. These findings suggest that ethanol alters OL development prior to increasing myelination in the NAc. Finally, chronic administration of the pro-myelination drug clemastine to mice with a history of heavy ethanol consumption further elevated ethanol intake and preference, suggesting that increased myelination may contribute to escalated drinking behavior. Together, these findings suggest that heavy ethanol consumption disrupts OL development, induces enhanced myelination in the NAc, and may drive further ethanol intake, reinforcing addictive behaviors.Significance Statement The myelin sheath is crucial for the development, maintenance, and normal functioning of the brain. Here, we provide evidence for the involvement of myelin alterations in alcohol (ethanol)-drinking behaviors. We show that chronic ethanol intake leads to enhanced myelination in the nucleus accumbens of adult mice. Moreover, we demonstrate that increasing myelination in heavily drinking mice leads to an escalation in ethanol intake. Thus, our results suggest that ethanol affects myelination processes, which, in turn, may affect ethanol-drinking patterns. Understanding the impact of ethanol on myelination could enhance our comprehension of alcohol addiction and open new avenues for treatment.

Effect of Repair Welding on Mechanical and Microstructural Behaviors of Heat Affected Zone in HY100 Steels

The mechanical properties and microstructural behaviors of multiple–repaired welds were investigated in the heat affected zone (HAZ) of HY100 steels. Test coupons were prepared from flux cored arc welds at the same location of weldments that had been repaired one, three and five times. The multiple–repaired welding caused continuous high temperature reheating of the HAZ. The effects of multiple–repaired welding to the HAZ on the fine–grained heat affected zone were investigated with respect to hardness, tensile strength and toughness. The peak temperature and cooling rate were obtained with quasi-stationary temperature distribution according to the modified Rosenthal equation. The prior austenite grains (PAG) that had been repeatedly reheated above A<sub>C3</sub> temperature were observed to have recrystallization and grain growth, and the distributed precipitates were identified as M<sub>3</sub>C and M<sub>23</sub>C<sub>6</sub>. Martensite–austenite constituents were identified through EBSD and TEM analyses to have a measured fraction of less than 2%. The PAG size (PAGS) of the original weld and the weld repaired one time were ~3 μm, while those that had been repaired three and five times were ~6 μm. The grain size strengthening and precipitation strengthening were calculated to be 294 MPa, 265 MPa, respectively, for the one time repaired and 220 MPa, 297 MPa for the five times repaired, respectively, for a total difference of 42 MPa. The welds repaired five times exhibited reasonable strength and impact toughness with insignificant variation in their microstructural behaviors.

PTOV1 exerts pro-oncogenic role in colorectal cancer by modulating SQSTM1-mediated autophagic degradation of p53

BackgroundProstate Tumor Overexpressed 1 (PTOV1) is overexpressed and associated with malignant phenotypes in various types of tumors. However, the detailed roles of PTOV1 and its underlying mechanism in CRC remain unclear.MethodsThe clinical significance of PTOV1 was assessed in clinical databases and CRC samples. The effects of PTOV1 on the tumor-associated phenotypes of CRC were detected by several in vitro assays and in vivo mouse models. Immunoprecipitation (IP) combined with protein mass spectrometry and Co-Immunoprecipitation (Co-IP) was used to identify p53 interacting with PTOV1. Immunofluorescence assay, western blot and transmission electron microscopy (TEM) analysis were used to evaluated the effects of PTOV1 on autophagy.ResultsHere, we revealed that PTOV1 was highly expressed in human CRC tissues, especially at advanced stages, and associated with reduced survival time among CRC patients. The upregulated PTOV1 promoted cell proliferation, migration, invasion, tumor growth and metastasis of CRC cells in vitro and in vivo. At the molecular level, PTOV1 destabilized p53 by activating autophagy and recruiting p53 for the cargo receptor SQSTM1 directed autophagic degradation. There was a negative expression correlation between PTOV1 and p53 in CRC tissues. Moreover, p53 overexpression or SQSTM1 knockdown reversed the pro-tumor phenotypes of PTOV1 in CRC.ConclusionOur study unveils the oncogenic role of PTOV1 in CRC progression, which was achieved by promoting SQSTM1 directed autophagic degradation of p53. These findings highlight the potential of targeting the PTOV1-SQSTM1-p53 axis as a therapeutic approach for CRC.

Demonstration of GaN HEMT with Cu-based Ti/TiN/Cu Ohmic metal and TiN/Cu gate metal: comparison with Au-based device

Abstract In this study, GaN high electron mobility transistor (HEMT) on silicon substrate was utilized Cu-based metal for the ohmic contacts (Source and Drain terminals) and the Schottky contact (Gate terminal) as part of the metallization process. Furthermore, the same epi-wafer was used in this study to fabricate Au-based HEMTs, which served as control samples. Transmission electron microscopy (TEM) analysis comparing Ti/TiN/Cu ohmic contacts of Cu-based HEMT to Control sample. The Au-based Ohmic contact forms rough surfaces, discrete TiN islands, and defects in the AlGaN layer, potentially degrading device reliability. The Cu-based Ohmic contact features a smooth surface, minimal defects in the AlGaN layer, a stable Ti/TiN interface, and effective prevention of Cu diffusion, enhancing device reliability and scalability. The specific contact resistance (ρ c) of the Cu-based and Au-based ohmic contact metals produced in this study were 6.68 × 10−6 Ω-cm2 (2.04 Ω mm−1) and 9.64 × 10−6 Ω-cm2 (2.06 Ω mm−1), respectively. In addition, compared with the Cu-based and Au-based HEMT components in this study, the Cu-based HEMT, which used TiN/Cu Gate metal, exhibited excellent electrical characteristics (IDS: 1023 mA mm−1, Gm: 570 mS mm−1). Through reliability testing, it was confirmed that the Cu-based Gate metal does not cause Vth shift or affect IDS. The fT and fmax of the Cu-based HEMT were 33.0 GHz and 99.6 GHz, respectively, which were 12.6 GHz (61.8%) and 26.1 GHz (35.5%) higher than the fT and fmax of the control sample (Au-based HEMT). This increase demonstrated that the Cu-based HEMT achieved higher switching speeds, enhancing its suitability for high-frequency applications. The Cu-based HEMT components achieved the same characteristics as Au-based HEMT components under frequency measurements. In future development of low-cost systems, copper-based HEMT components will play an important economic role.

Polyethylene Polyamine-Modified Chitosan Aerogels: Enhanced CO2 Adsorbents with Lamellar Porous Structures

Due to the continuous growth of global carbon dioxide emissions, the development of cost-effective carbon dioxide capture technology has attracted extensive attention. Amino-modified chitosan aerogels with lamellar porous structures are good candidates as carbon dioxide adsorbents because of their degradable properties and low energy consumption. Polyethylene polyamine-modified chitosan aerogels (PEPA-CSs) were prepared through a process of crosslinking and freeze-drying using a chitosan solution, polyethylene polyamine (PEPA), and epichlorohydrin (ECH) as raw materials. The amino group of PEPA was proven to be successfully grafted on the chitosan surface by FITR and XPS. The SEM and TEM analysis showed a rich three-dimensional porous structure and a good rigidity and bearing capacity of the PEPA-CS. The adsorption capacity was significantly increased by PEPA grafting with a maximum value of 1.59 mmol/g at 25 °C and 1 bar through both physical and chemical interactions, which indicates a potential for broad application prospects in industrial CO2-capture applications.

Low-Temperature Synthesis of NiO Structures: Tailoring Morphology for Enhanced Dielectric Performance

Abstract Abstract:
Nickel oxide (NiO) is a widely studied material for energy storage applications due to its excellent structural and functional properties. This study explores the effect of synthesis pH on the structural, optical, and dielectric properties of NiO nanoparticles to optimize their performance. NiO was synthesized via a hydrothermal method at pH 8 and 12, followed by calcination at 200°C. At pH 12, X-ray diffraction confirmed the phase transition from β-Ni(OH)₂ to NiO, while TEM analysis revealed the formation of a one-dimensional (1D) structure. Optical studies using UV-visible spectroscopy and photoluminescence revealed defect states that contribute to improved energy storage performance. Dielectric studies revealed superior performance at pH 12. Electrochemical cyclic voltammetry confirmed the enhanced stability and energy storage capabilities of NiO with 1D structure. These findings establish NiO synthesized at pH 12 as a promising candidate for advanced energy storage technologies.
Keywords: NiO nanoparticles, hydrothermal synthesis, Optical properties, Dielectric properties, Energy storage.


Cost-effective adsorption of cationic dyes using ZnO nanorods supported by orange peel-derived carbon.

Here, porous carbon (PC) and ZnO nanorods@PC (ZnO-NR@PC) composite derived from orange peel (OP) have been synthesized via a simple carbonization process. The prepared materials have been characterized by XRD, FT-IR, TEM, and BET analysis. The adsorptive properties of the prepared PC and ZnO-NR@PC composite have been investigated toward methylene blue (MB) and crystal violet (CV) cationic dyes from their aqueous solutions. The adsorption studies concluded that the maximum adsorption efficiency was achieved after 90min in the basic conditions (pH = 10). Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin non-linear isotherm models were applied to fit the experimental data. The adsorption of MB and CV dyes by the OP is fitted with the Freundlich model, and the adsorption of both dyes by the PC and the ZnO-NR@PC composite fitted with the Langmuir model. The estimated maximum adsorption capacity estimated from the adsorption of MB and CV by the ZnO-NR@PC composite was 74.45 and 74.89mg/g, respectively. The calculated adsorption free energy from D-R and Temkin models indicates the adsorption of MB, and CV dye molecules by the OP, PC, and ZnO-NR@PC composite may be physical. The kinetic studies revealed the adsorption of MB and CV dyes onto the OP, PC and ZnO-NR@PC composite fitted with the pseudo-second-order model. On the otherhand, the thermodynamic studies confirmed the adsorption of MB, and CV dyes onto ZnO-NR@PC composite is an endothermic and spontaneous process. Furthermore, the prepared materials displayed high adsorption stability with an overall removal efficiency of about 90% after five cycles. The mechanism of MB and CV dyes by the ZnO-NR@PC composite is proposed to be controlled by electrostatic bonding, π-π interactions, and ion exchange. The results indicated the potential ability of OP-derived porous carbons as adsorbents for cationic dyes from aqueous media.

Processing and Characterisation of Alumina/Eucryptite Nanostructured Composites

Alumina is one of the most studied and used ceramic materials, but increasing its fracture toughness is still a challenge for many specific impact applications. Adding a second phase with a low coefficient of thermal expansion (CTE) to an alumina matrix can enhance the matrix’s mechanical properties, reduce its sintering temperature, and increase its toughness by generating compressive stresses on the alumina particle surface. In this study, nanostructured alumina/eucryptite composites were prepared to achieve enhanced toughness. First, eucryptite (Li₂O·Al₂O₃·2SiO₂) nanoparticles were successfully synthesised via colloidal heterocoagulation. These nanoparticles were then used to reinforce alumina matrices through slip casting followed by conventional sintering. Complete crystallisation of eucryptite was achieved at 850 °C with a CTE of 0.46 × 10 −⁶ °C −¹. Transmission electron microscopy analysis revealed that the average particle size was 28.5 ± 14.5 nm. To achieve a relative density of 95.3%, the composite containing 5 vol.% eucryptite required sintering for 1 h at 1400 °C whereas pure alumina required 2 h at 1600 °C. This reduction in sintering temperature (by up to 200 °C) helped to improve the fracture toughness, with the alumina grain size decreasing from 2.3 to 0.9 µm. The advantages of the new composite are the more economically viable and environmentally friendly way of producing the lithium aluminosilicate nanoparticles, compared to the production of ceramic frits at high temperatures (~1500 °C).

Enhancing Cd and Pb tolerance of Robinia pseudoacacia (black locust) by regulating antioxidant defense system, macroelement uptake and microstructure.

Woody plants had received considerable attention for the phytoremediation of heavy metal-contaminated soil. This study aimed to investigate the changes in antioxidant enzyme activity, macroelement uptake, and microstructure of the woody plant Robinia pseudoacacia (black locust) for the phytoremediation of cadmium (Cd) and lead (Pb) co-contaminated soil based on dynamic sampling. The results showed that black locust demonstrated strong tolerance in Cd and Pb co-contaminated soil. After 30-120 d of cultivation, the activities of superoxide dismutase (SOD), peroxidase (POD), and the macroelement (K and Ca) content in plant leaves significantly declined in response to Cd and Pb. However, after 160 d of cultivation, the antioxidant enzyme activities, chlorophyll, sulfhydryl, and soluble protein contents, as well as Ca and Mg content in plant leaves were returned to normal levels under the 40mg·kg-1 Cd and 1000mg·kg-1 Pb contaminated soil (CdPb3). Meanwhile, K content in plant leaves under the CdPb3 treatment was significantly (P<0.05) increased by 68.9% compared to the control. Cd and Pb was primarily accumulated in black locust roots. Scanning electron microscope (SEM) analysis indicated that the sieve tubes in the roots and stems of plant might block the transport of Cd and Pb. Transmission electron microscope (TEM) analysis indicated that the number and volume of osmiophilic particles in plant leaves were increased and the cell walls were thickened in response to Cd and Pb stress. Path analysis further indicated that the growth of plant was related to macroelements uptake and physiological change (photosynthesis, antioxidant enzyme activity, and chelation). Thus, black locust could effectively regulate the antioxidant defense system, macroelement absorption, and microstructure to enhance plant tolerance to Cd and Pb stress. Moreover, black locust could maintain the normal urease, acid phosphatase, and sucrase activities in the Cd and Pb co-contaminated soil. These findings suggested that black locust could be considered as a useful woody plant for the phytostabilization in Cd and Pb-contaminated soil.

Effect of Powdered Nano-Local Banded Iron Formation (BIF) Rock on Some Mechanical Properties of Cementitious Concrete

Banded Iron Formation (BIF) rocks are a significant source of iron ore, and they can also be used in the production of cementitious materials. However, the BIFs of the Egyptian Eastern Desert (ED) are not currently employed in steel iron manufacturing due to their elevated silica content and the technical challenges and high cost associated with extracting iron ore from them. Furthermore, the incorporation of nano-sized particles of BIF into cementitious mortar may impart specific characteristics that could enhance mechanical strength and durability, or even contribute to sustainability. This study examines the impact of nano- and powder-based materials derived from locally sourced BIF rocks on the properties of cementitious concrete when used as partial replacements for Ordinary Portland Cement (OPC). A comprehensive evaluation was conducted on concrete mixtures with varying cement replacement ratios, 1, 2, 3, and 4%, to assess the impact on key mechanical properties at different curing ages, 7, 28, and 90 days. The concrete samples exhibited significant enhancements in mechanical properties at all curing periods. The 2% Nano-BIF replacement yielded the most notable increase. Furthermore, X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) analysis demonstrated that the Interfacial Transition Zone (ITZ) between the cement paste and aggregates exhibited a robust compacted bond, indicating that local nano-BIFs have the potential to serve as an effective additive for enhancing the mechanical properties of cementitious concrete.

Comparative in-vitro and in-vivo evaluation of spherulites and cubosomes of Irinotecan for lung targeting.

The present investigation aimed at the comparative evaluation of the developed nanocarriers, viz. spherulites and cubosomes for lung targeting. Both the spherulites and cubosomes were characterized for their entrapment efficiency, drug loading, size and zeta potential, in-vitro drug release profile, surface morphology, hemocompatibility, and in-vivo pharmacokinetic and lung biodistribution. The optimized batches of spherulites and cubosomes possessed high entrapment efficiency and drug loading with size around 200 nm, which is suitable for lung targeting. The zeta potential value for both the nanoformulations was found to be between -20 and -30 mv indicating the physical stability against aggregation. The SEM and TEM analysis revealed the presence of spherical and discrete particles in both the types of nanocarriers. Water channels were observed in case of cubosomes. Spherulites and cubosomes showed pH-dependent drug release with lower release at physiological pH while higher release at the pH of the tumor microenvironment. Both spherulites and cubosomes exhibited highly significant increase in the half-life and mean residence time in the plasma. The prepared nanoformulations were hemocompatible and had higher lung targeting potential compared to the plain drug solution.

Morphological and structural characterization of reduced graphene oxide films prepared by RF magnetron sputtering

This study investigates the synthesis and characterization of reduced graphene oxide (rGO) films deposited via radio frequency (RF) magnetron sputtering to advance the development of high-quality graphene-based materials for industrial applications. Key growth parameters—RF power, argon flow rate, and deposition time—were systematically optimized to achieve controlled film quality and targeted morphological and electrical properties. Raman spectroscopy provided insights into vibrational characteristics, with the ID/IG ratio indicating favorable graphitization levels at optimized argon flow rates. Morphological assessments through Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM) revealed uniform film structure and minimal surface roughness, enhancing the films’ suitability for applications requiring smooth surfaces. Transmission Electron Microscopy (TEM) analysis confirmed the presence of few-layer and multilayer rGO sheets, with consistent lattice structures validated through high-resolution TEM and Fast Fourier Transform (FFT) analysis. This research establishes a robust framework for synthesizing high-quality rGO films with tailored characteristics, paving the way for potential applications in energy storage, sensors, and electronic devices.