Electron Microscopy Images Research Articles

Biofilm destruction activity of α-tocopherol against Staphylococcus aureus, Proteus mirabilis and Pseudomonas aeruginosa.

Antibiotic resistance and the persistence of sessile cells within biofilms complicate the eradication of biofilm-related infections using conventional antibiotics. This highlights the necessity for alternate therapy methods. The objective of this study was to investigate the biofilm destruction activity of α-tocopherol against Staphylococcus aureus, Proteus mirabilis and Pseudomonas aeruginosa on polystyrene. α-Tocopherol showed significant biofilm destruction activity on the pre-formed biofilms of S. aureus (45-46%), Pr. mirabilis (42-54%) and Ps. aeruginosa (28%). Resazurin assay showed that α-tocopherol disrupted all bacteria biofilms without interfering with their cell viability. Scanning electron microscope images showed lower bacterial cell count and less compacted cell aggregates on polystyrene surfaces after treatment with alpha-tocopherol. This study demonstrated the biofilm destruction activity of alpha-tocopherol against S. aureus, Pr. mirabilis and Ps. aeruginosa. α-Tocopherol could potentially be used to decrease biofilm-associated infections of these bacteria.

Fractal Analysis of Volcanic Rock Image Based on Difference Box-Counting Dimension and Gray-Level Co-Occurrence Matrix: A Case Study in the Liaohe Basin, China

Volcanic rocks, as a widely distributed rock type on the earth, are mostly buried deep within basins, and their internal structures possess characteristics by irregularity and self-similarity. In the study of volcanic rocks, accurately identifying the lithology of volcanic rocks is significant for reservoir description and reservoir evaluation. The accuracy of lithology identification can improve the success rate of petroleum exploration and development as well as the safety of engineering construction. In this study, we took the electron microscope images of four types of volcanic rocks in the Liaohe Basin as the research objects and comprehensively used the differential box-counting dimension (DBC) and the gray-level co-occurrence matrix (GLCM) to identify the lithology of volcanic rocks. Obtain the images of volcanic rocks in the research area and conduct preprocessing so that the images can meet the requirements of calculations. Firstly, calculate the different box-counting dimension. Divide the grayscale image into boxes of different scales and determine the differential box-counting dimension based on the variation of grayscale values within each box. The differential box-counting dimension of basalt ranges from 1.7 to 1.75, that of trachyte ranges from 1.82 to 1.87, that of gabbro ranges from 1.76 to 1.79, and that of diabase ranges from 1.78 to 1.82. Then, the gray-level co-occurrence matrix is utilized to extract four image texture features of volcanic rock images, namely contrast, energy, entropy, and variance. The recognition of four types of volcanic rock images is achieved by combining the different box-counting dimension and the gray-level co-occurrence matrix. This method has been experimentally verified by volcanic rock image samples. It has a relatively high accuracy in identifying the lithology of volcanic rocks and can effectively distinguish four different types of volcanic rocks. Compared with single-feature recognition methods, this approach significantly improves recognition accuracy, offers reliable technical support and a data basis for volcanic rock-related geological analyses, and drives the further development of volcanic rock research.

Quantitative Determination of High-Frequency Voltage Attenuation in an Electric-Pulse-Excited Stroboscopic Transmission Electron Microscope.

High-frequency electric pulse signals are often applied to stimulate functional materials in devices. To investigate the relationship between materials structure and dynamic behavior under high-frequency electric excitation, the stroboscopic imaging mode is widely used in a transmission electron microscope (TEM). From a technical point of view, it is crucial to quantitatively determine high-frequency attenuation in an electric-pulse-excited stroboscopic TEM. Here, we propose the quantitative method to evaluate the voltage attenuation by using magnification variation of defocused bright-field transmission electron microscopy images in a stroboscopic mode when applying high-frequency electric pulse signals onto a model system of two opposite tungsten tips. The negative voltage excitation possesses higher high-frequency voltage attenuation than the positive voltage excitation due to the possible nonreciprocal transmission of the triangle waves within the circuit between the biasing sample holder and the arbitrary waveform generator. Our approach of high-frequency attenuation determination provides the experimental foundation for quantitative analysis on the dynamic evolution of materials structure and functionality under electric pulse stimuli.

Enhancing Carbon Fiber-Reinforced Polymers’ Performance and Reparability Through Core–Shell Rubber Modification and Patch Repair Techniques

Carbon fiber-reinforced polymers (CFRPs) are widely used in high-performance applications, but their inherent brittleness and susceptibility to impact damage remain critical challenges. This study investigated the effect of core–shell rubber (CSR) particles as impact modifiers on the mechanical properties of CFRPs and evaluated patch repair techniques for damaged CFRP panels. Mechanical tests, including flexural, tensile, short-beam, fracture toughness, and impact tests, were conducted on reference and CSR-modified specimens to assess their structural performance. The CSR-modified samples demonstrated significant improvements in energy absorption and fracture toughness, with a 50% increase in impact strength and up to 181% improvement in absorbed energy during Mode I fracture testing. However, slight reductions in flexural and tensile strengths were observed due to the softening effect of CSR particles. Fracture surface analysis revealed distinct failure mechanisms, with Scanning Electron Microscopy imaging showing consistent fiber pull-out behavior in tensile and flexural tests, but more stable delamination propagation in CSR-modified specimens during short-beam shear tests. Patch repair effectiveness was assessed through drop-weight impact tests on damaged panels repaired with patches containing CSRs of two thicknesses. Patches of equal thickness to the damaged panel successfully restored structural integrity and enhanced energy absorption by 37% compared with the reference samples, while thinner patches (as a suggestion to reduce production costs) failed to withstand impact loads effectively. Non-destructive testing (NDT) via ultrasonic C-scans confirmed reduced delamination and damage depth in CSR-modified repaired panels, validating the toughening effect of CSR particles. These findings demonstrate the potential of CSR-modified resins to improve CFRPs’ performance and provide effective repair solutions for extending the service life of damaged composite structures, rendering them especially suitable for applications demanding high damage tolerance and durability, including aerospace structures, automotive body panels, and energy-absorbing crash components.

WxMo1‐xO2 Nanocrystals Synthesized by WSe2‐Assisted Chemical Vapor Deposition Method

Transition metal oxide alloys, with tunable stoichiometric ratio, have garnered significant attention due to their unique electronic structure and diverse chemical properties. However, synthesis of micron‐scale, single‐crystalline transition metal oxide alloys remains a challenge due to their unique alloy structure and stringent synthesis conditions. Herein, a WSe2‐assisted chemical vapor deposition method is reported for synthesizing WxMo1‐xO2 nanocrystals with various dimensions: nanorods, nanoplates, and nanodots. The microscopic (optical microscope, atomic force microscope, and scanning electron microscope) images reveal that the nanocrystals have well‐defined non‐layered polyhedral structures. The elemental composition is confirmed by Raman spectroscopy and energy dispersion spectroscopy. The change in phonon symmetry in nanorods and the blue shift of Raman peaks in nanocrystals demonstrate the significant role of the quantum confinement effect. The spatial distribution of the various dimensional nanocrystals provides insights into the possible growth mechanism and the key role of the WSe2 in growth. The WSe2‐assisted growth strategy for alloyed nanocrystals can expand the transition metal oxide alloy material library and offer a platform for exploring additional properties of transition metal oxide alloys.

Cytotoxicity of single and binary mixtures of copper and silica nanoparticles exposed to Nitzschia closterium f. minutissima.

A large number of nanoparticles are produced and enter the aquatic environment, where they interact with each other, posing a potential threat to aquatic organisms. The toxicity of two types of nanoparticles (nCu and nSiO2) on Nitzschia closterium f. minutissima (N. closterium f. minutissima) was investigated in this study by examining changes in microalgal cell density, instantaneous fluorescence rate (Ft), and a range of antioxidant parameters in the cells. It was found that both nCu and nSiO2 showed time- and concentration-dependent toxic effects on N. closterium f. minutissima. nSiO2 could promote microalgae growth at low concentrations by providing Si, an essential element for the synthesis of siliceous shells. As the exposure time increased, both the growth and photosynthetic efficiency of the microalgae were inhibited. Nanoparticles also produced oxidative stress and caused lipid peroxidation in the microalgae. In the meantime, SOD and CAT activity were altered to protect cells from oxidative damage. Inverted biomicroscopy images showed that the microalgae enhanced their cell size to adapt to the environmental stress as exposed to 1 mg/L nCu. Scanning electron microscope (SEM) images showed that 10 mg/L nSiO2 could adsorb nCu and reduce the toxic effect of nCu on the microalgae, while 30 mg/L nSiO2 caused mechanical damage to microalgal cells and accelerated the internalization of nanoparticles and Cu2+ in the cells.

Soil data from the Barbastro-Balaguer gypsum belt, NE Spain.

The dataset [1] hosts pedological info and images of the lands -locally known as chesas- of the outcropping gypsiferous core of the Barbastro-Balaguer anticline (Fig. 1). It stands out in the landscape for the linear reliefs due to outcrops of dipping strata with differential resistance to erosion, and also because of its whitish color (Fig. 2) and gypsophilous vegetation. This gypsum outcrop was named in the 19th Century [2] as a gypseous belt, and has been further studied by other geologists like [3,4] and by civil engineers e.g. Hué and Llamas [5]. Traditionally chesas were rangeland, with sparse almond and olive trees and rainfed winter cereals confined at the flat -and often terraced- valley bottoms, or vales as known in NE Spain. The chesas have attracted the attention of botanists [[6], [7], [8]], foresters [9,10], and soil hydrophysical properties researchers [11]. Moreover, public interest is increasing as the administrations are establishing rules for nature protection in the gypseous lands, e.g., a demarcation of 137 km2 set within the chesas was declared a Special Conservation Area "ES2410074 Yesos de Barbastro", and then protected by the Habitats Directive of European Union. Also, plant physiologists are focusing on the adaptations of plants to gypsum as reviewed by Escudero et al. [12]. No soil map is available, but according to [13,14] the Gypsic Haploxerepts [15] are dominant. In the absence of a soil map, our dataset can help in the decisions to be made by the authorities, as is the case for water allocation to irrigated estates both in operation and planned, or for authorizations for the spreading of pig slurry. The herein presented soil data were collected with the classical techniques of pedological prospection. The dataset [1] contains the scans in .TIFF format of 150 whole thin sections of the soils, under both plane polarized light (PPL) and cross polarized light (XPL). Moreover, this dataset directs to a freely downloadable book [16] with the corresponding pedological descriptions, chemical and physical analyses, hydrophysical data, and scanning electron microscope images of the soils, plus micrographs of relevant pedofeatures of thin sections seen under petrographic microscope. The dataset [1] also presents a .xlsx file with an English translation of all figure captions of [16], including those of micrographs, and two more .xlsx files with analytical data. All data can be reused directly by naturalists, engineers, technicians and public servants in charge of environmental law development and enforcement, as well as by people involved in citizen science activities. Thin sections remain stored at EEAD and can be examined at our premises upon request.

Enhancement of Strength and Hardness in Copper–Chromium–Zirconium Alloy Using Single‐Pass Multi‐Angular Twist Channel Extrusion: A Microstructural and Deformation Study

Herein, the strength and hardness of copper–chromium–zirconium alloy are enhanced in a single pass by a severe plastic deformation (SPD) technique called the multiangular twist channel extrusion (MATE) process. In equal channel angular pressing (ECAP) and twist extrusion (TE), requisite strain and uniformity are achieved through several extrusion passes. MATE is a single‐pass novel SPD technique developed by integrating TE with the ECAP followed by a direct channel zone. The deformation behavior of metal in the MATE process is elucidated through experimental and microstructural studies conducted in each zone. The MATE‐processed Cu–Cr–Zr alloy achieves a hardness of 184.4 Hv and a tensile strength of 645.2 MPa, reflecting an increase of 80.43% and 69.7%, respectively, relative to the annealed condition. The electrical conductivity of the MATE‐processed Cu–Cr–Zr alloy decreases to 74.29% International Annealed Copper Standard. The electron backscatter diffraction investigation reveals an average grain size of 2.8 μm, with 61% comprising low‐angle grain boundaries, while the calculated dislocation density, from X‐ray diffraction analysis, is 3.93 × 1014 m−2. The transmission electron microscopy image verifies the existence of dislocations and precipitates in the Cu–Cr–Zr alloy. The experimental and microstructural findings in each zone have aligned effectively.

First-principles calculations of quartz–coesite interfaces

Atomistic interface structures compatible with periodic boundary conditions for the strain-induced subsolidus martensitic transition between quartz and coesite have been investigated. We identified layers of atoms that remained unchanged in terms of neighbor interactions throughout the transformation. Our analysis revealed that the orientation relationships between quartz and coesite, namely (1011)Qz||(010)Coe and (1321)Qz||(010)Coe, are consistent with experimental observations. Using density-functional-theory-based tight-binding model calculations, we determined an interface energy of approximately 660 mJ m−2 for these interfaces and strain energies of 196 (6) and 2760 (160) J mol−1 atom−1 for the (1321)Qz||(010)Coe and (1011)Qz||(010)Coe oriented interfaces, respectively. To visualize these interface structures and facilitate their identification in experiments, we simulated high-resolution transmission electron microscopy images and electron diffraction patterns.

Feasibility of online optical diagnostics during gas-phase synthesis of few-layer graphene based on elastic light scattering measurements

Gas-phase synthesis is a promising method for scalable production of high-quality free-standing few-layer graphene (FLG) particles. This study assesses the feasibility of elastic light scattering in characterizing particle morphology and distinguishing FLG from soot-like particles that may also be produced concurrently during gas-phase synthesis. FLG particle morphology is modeled based on tomographic electron microscopy images of FLG particles produced within a plasma reactor, whereas synthetic soot particles are generated via a cluster–cluster aggregation algorithm based on morphological parameters typical of flame soot. Light scattering properties of ensembles of synthetic FLG and soot particles are simulated via the discrete dipole approximation (DDA) and the multi-sphere T-matrix method, respectively. Angle-resolved scattering properties of ensembles of FLG and soot particles are analyzed to evaluate the feasibility of scattering-based diagnostics and identify potential measurement configurations for characterizing particle morphology. Overall, certain scattering properties, especially the depolarization ratio, are observed to be sensitive to the distinctive morphological aspects of FLG and soot, which highlights the promise of light scattering-based diagnostics for characterizing morphology during gas-phase synthesis of FLG.

THE EFFECT OF GLAZING AND THERMOCYCLING ON THE SURFACE ROUGHNESS OF DIFFERENT CAD/CAM MILLED CERAMIC LAMINATE VENEERS WITH SEM OBSERVATIONS

CAD/CAM technologies are one of the rapidly developing fields in digital restorative dentistry. The objective of this in vitro study was to evaluate the influence of glazing and thermocycling on the surface roughness values of four different types of milled CAD/CAM ceramic materials. Aim - to evaluate the effects of glazing and thermocycling on the surface roughness values of four different types of CAD/CAM ceramic veneers. This study hypothesized that there would be a statistically significant difference in surface roughness values between glazed and nonglazed CAD/CAM materials across the four tested ceramics. Materials and Methods - As part of the investigation,80 CAD/CAM ceramic veneer samples were milled using CAD/CAM system (inLab MC XL CEREC, Dentsply Sirona, Germany). The processing occurred after scanning of the first right typodont incisor of the upper jaw model prepared with the palatal chamfer preparation design without approximal involvement (KaVo, Germany) via an Omnicam scanner (CEREC, Dentsply Sirona, Germany). Four different CAD/CAM ceramic materials were evaluated in this study: lithium disilicate (IPS E.max CAD, Ivoclar, Germany), leucite-reinforced ceramic (IPS Empress CAD, Ivoclar, Germany), feldspathic ceramic (Cerec, CEREC, Dentsply Sirona, Germany), and hybrid ceramic (Cerasmart, GC, Japan). The 80 samples were categorized into four groups (20 in each, n=20), further divided into glazed and nonglazed subgroups (10 samples, n=10). All specimens underwent 10,000 thermal cycles.The surface roughness values were evaluated at three stages: post-milling, post-glazing, and post-thermocycling. Scanning electron microscope images (magnification 100x, 250x, 500x, 1000x) were captured for each material before glazingand after thermocycling. Results -Significant differences in surface roughness values were observed among materials after glazing and thermocycling. Surface roughness notably decreased following glazing. The Cerec group exhibited significantly higher surface roughness values after glazing compared to Cerasmart, Empress, and E.max groups (p < 0.05). Analysis of the glazed surfaces after thermocycling also revealed significant differences among the groups (p < 0.05). Tamhanes T2 post-hoc test showed that the Cerec groups average surface roughness values were significantly higher than those of Cerasmart, Empress, and E.max after thermocycling (p < 0.05). For non-glazed samples, thermocycling similarly led to higher surface roughness values in the Cerec group compared to the other three groups (p < 0.05). These findings highlight the effects of glazing and thermocycling on the surface roughness of CAD/CAM ceramic materials, reflecting their clinical behavior. Conclusion - Statistically significant differences were found between the glazed and non-glazed samples in terms of surface roughness. Among the tested materials, the Cerec group consistently showed higher roughness values compared to Cerasmart, Empress, and E.max (p < 0.05). Glazing and thermocycling significantly influenced the surface roughness of all groups.

Native state structural and chemical characterisation of Pickering emulsions: A cryo-electron microscopy study.

Transmission electron microscopy can be used for the characterisation of a wide range of thin specimens, but soft matter and aqueous samples such as gels, nanoparticle dispersions, and emulsions will dry out and collapse under the microscope vacuum, therefore losing information on their native state and ultimately limiting the understanding of the sample. This study examines commonly used techniques in transmission electron microscopy when applied to the characterisation of cryogenically frozen Pickering emulsion samples. Oil-in-water Pickering emulsions stabilised by 3 to 5nm platinum nanoparticles were cryogenically frozen by plunge-freezing into liquid ethane to retain the native structure of the system without inducing crystallisation of the droplet oil cores. A comparison between the droplet morphology following different sample preparation methods has confirmed the effectiveness of using plunge-freezing to prepare these samples. Scanning transmission electron microscopy imaging showed that dry droplets collapse under the microscope vacuum, changing their shape and size (average apparent diameter: ∼342nm) compared to frozen samples (average diameter: ∼183nm). Cryogenic electron tomography was used to collect additional information of the 3D shape and size of the emulsion droplets, and the position of the stabilising nanoparticles relative to the droplet surface. Cryogenic energy dispersive X-ray and electron energy loss spectroscopy were used to successfully obtain elemental data and generate elemental maps to identify the stabilising nanoparticles and the oil phase. Elemental maps generated from spectral data were used in conjunction with electron tomography to obtain 3D information of the oil phase in the emulsion droplets. Beam-induced damage to the ice was the largest limiting factor to the sample characterisation, limiting the effective imaging resolution and signal-to-noise ratio, though careful consideration of the imaging parameters used allowed for the characterisation of the samples presented in this study. Ultimately this study shows that cryo-methods are effective for the representative characterisation of Pickering emulsions.

Impact of high pressure impregnation and air drying on the quality of Dosidicus gigas slices

Humboldt squid (Dosidicus gigas) is the most abundant cephalopod in the fishing industry, and its high nutritional and organoleptic properties make it a go-to food product for consumers. Therefore, developing new processing techniques seems imperative to minimize quality deterioration and provide products with appropriate characteristics. The study aimed to determine the effect of high-pressure impregnation (HPI) pretreatment on hot air-drying kinetics and the quality of Humboldt squid slices. Various pressures, times, and concentrations of osmotic solution during HPI were evaluated, followed by drying at 40 and 60 °C. The HPI pretreatment reduced the drying time by around 26% when dried at 40 °C, and only 18% when dried at⋅ 60 °C compared with unpretreated samples. The Weibull, Page, and Logarithmic models were considered for experimental drying curve modeling. Diffusion coefficient values varied from 3.82 to 6.59 × 10−9 m2/s for all drying conditions. Moreover, the color, texture, and water-holding capacity were determined. Rehydration capacity values increased due to less damage to cellular tissue than the control (HPI-untreated dried samples). Also, scanning electron microscope (SEM) images showed a compacted structure of HPI-dried squid samples. Overall, HPI proved to be a beneficial pretreatment as it reduced drying time and improved the quality characteristics of Humboldt squid.

Impact of Gd, Pr, Yb, and Nd doping on the magnetic properties of Mg-ferrite nanoparticles

This study aimed to synthesize MgFe1.9Ln0.1O4 (where, Ln = Yb, Pr, Gd, and Nd) ferrite nanoparticles via the sol-gel process and investigate their structural, morphological, and magnetic properties for potential hyperthermia applications. X-ray diffraction analysis (XRD) confirmed the cubic spinel structure for all samples. Transmission electron microscopy (TEM) images revealed nanometer-scale dimensions and nearly spherical morphology. Vibrating sample magnetometer measurements (VSM) indicated superparamagnetic behavior, with decreasing saturation magnetization (Ms) observed as Ln3+ content decreased. Specific absorption rate (SAR) analysis at 198 kHz demonstrated the influence of Ln3+ substitution on magnetic properties. Compared to existing studies, Ln3+ substituted (Yb, Pr, Gd, and Nd) nanoparticles demonstrate tunable magnetic properties and enhanced SAR performance, offering a more efficient design for hyperthermia treatment of solid tumors.Graphical

Crude Oil Desulfurization by Polystyrene/Graphene Nanocomposite Membranes

The main aim of this paper is to evaluate the effect of graphene nanoplatelets (GNPs) on the desulfurization of the polystyrene nanofibers. Hence, different loadings of GNP, 0.5, 1, 1.5, and 2 wt.% GNP was incorporated into the polystyrene nanofibers using electrospinning technique. Several characteristics of the electrospun membranes were investigated. The obtained field emission scanning electron microscopy (FE-SEM) images confirmed the formation of uniform fibers and proper distribution of the particles in the electrospun structures. In addition, thinner fibers with smaller pore sizes were formed by addition of the GNPs into the nanofibrous mats. Moreover, the hydrophobic behavior reduced by increment of GNP content in the polystyrene nanofibers. Fourier transform infrared spectra (FTIR) confirmed the interaction of the polymer chains with the loaded filler particles. Furthermore, introduction of the GNP nanofillers in the decrease of the crude oil sulfur content from 2.8% to 2.6% via addition of 0.5 wt.% of GNPs into the as-spun fibers. Further reduction of the sulfur content (to 1.8%) was also obtained by embedding 2 wt.% of GNPs. Overall, the obtained data manifested that the electrospinning composite membranes are good candidate material for removing sulfur from crude oil.

Nonlocal effects on curved double-walled carbon nanotubes based on nonlocal theory

Curved double-walled carbon nanotubes (CDWCNTs) are crucial components in nanoelectronics, mechanical sensors, and composite materials due to their unique geometry and structural properties. Electron microscopy images have revealed that carbon nanotubes are rarely perfectly straight, often exhibiting curvature or waviness along their length due to inherent geometrical imperfections. The accurate mechanical modeling of these structures is essential, particularly to capture size-dependent effects that classical elasticity theories fail to account for. In this study, a novel analytical framework was introduced for combining the initial value method with the approximate transfer matrix approach to analyze the mechanical behavior of CDWCNTs under anti-plane loading within the framework of nonlocal elasticity theory. The proposed methodology provides an effective and computationally efficient alternative to traditional analytical approaches. By analyzing displacements, rotations, bending moments, and shear forces, substantial deviations were revealed between classical and nonlocal elasticity solutions, particularly as the dimensionless nonlocal parameter R/γ decreased. The results show that nonlocal effects become dominant at smaller size parameters, especially in displacements, rotations, and bending moments, while shear forces remain unaffected. These findings emphasize the critical role of nonlocal effects in accurately predicting nanoscale mechanical responses and offer valuable insights for modeling advanced nanostructures in emerging technologies, such as microelectromechanical systems and nanotechnology. Convergence studies have confirmed the accuracy and stability of the proposed approach, thereby establishing this as a robust tool for modeling nanoscale structures.

Highly tunning of dielectric and photocatalytic properties of crystalline ZnO semiconductor: Functionality of Ba additives

Abstract In the present work, the concentration of Ba-additive played a significant role in advancing the dielectric properties and photo-removal activity of ZnO semiconductor for methylene blue dye. Ba doped ZnO semiconductor with different doping concentrations (Zn1-xBaxO, x = 0.003, 0.005, 0.007 and 0.009 wt.%) were grown by solid-state reaction route. The X-ray diffraction (XRD) data confirmed the formation of the wurtzite structure of ZnO along with the presence of BaO-based secondary phase (SP). The XRD peak intensity related to the SP was found to increase with the increase of Ba concentration. Microstructural analyses through scanning electron microscope (SEM) images and energy-dispersive X-ray analysis (EDS) showed that with the addition of Ba, a gradual increase in the grain size was observed. Furthermore, SP segregated at the grain boundary and showed an increasing trend with doping. The emergence of secondary phases with Ba concentration was confirmed with the help of supplementary spectroscopic characterizations including Fourier transform infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance. The presence of BaO secondary phase has shown a benefit effect on the dielectric and photodegradation properties of ZnO material. The remarkable resistance reduction suggested that the higher Ba concentrations significantly enhance charge carrier mobility. For wastewater treatment uses, BZO9 photocatalyst exhibited a perfect degradation efficiency of 90.1% for methylene blue (MB) removal after 210 min of visible light illumination.

Improving Nanoparticle Size Estimation from Scanning Transmission Electron Micrographs with a Multislice Surrogate Model.

The computational cost of simulating scanning transmission electron microscopy (STEM) images limits the curation of large enough data sets to train accurate and robust machine learning networks for deep feature extraction from atomically resolved STEM images. For nanoparticle size estimation in particular, a diverse data set is essential due to the large variations in size, shape, crystallinity, orientation, and dynamical diffraction effects in experimental data. To address this, we train a 3D convolutional neural network to predict STEM images from voxelized atomic models, achieving a 100x speed-up compared to traditional multislice simulations while maintaining high image quality. We then generate a data set of 100.000 synthetic multislice images and investigate the performance of different size-estimator architectures as a function of training set size. A ResNet18-based model trained on 4000 real and 100.000 synthetic images is found to perform the best, reducing the median size-estimation error from 9.89% without synthetic data to 5.26%.

510. Bacteriophages as Drug Delivery Vehicles for Polymyxin B

Abstract Background The goal of this project is to develop a safer, more effective formulation of polymyxin B for E. coli bacteremia. Polymyxins are a family of cyclic lipopeptides that display exceptional antibiotic activities toward gram-negative pathogens such as E. coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. The PMB label includes an FDA black box warning for serious nephrotoxicity and neurotoxicity. However, today, with the growing emergence of “superbugs” and a dry antibiotic discovery pipeline, PMB is increasingly used as a last-line therapy to treat systemic infections. Thus, although PMB is a potent antibacterial agent, its toxicity currently prevents its use as an earlier or more widespread treatment. Transmission electron microscopy (TEM; negative stain) images of anti-LPS phage bound to gram-negative organisms. Phages were labeled with gold nanoparticles (dark spheres) coated with antibodies against pVIII, allowing phages to be easily identified (red darts). Gold-labeled anti-LPS phage are shown (A) without bacteria; or incubated with (B) E. coli DH5α; (C) E. coli ATCC BAA 1161; (D) A. baumannii ATCC 19606. Phage width is increased by the labeling reagents. Scale bars = 500 nm. Methods We engineered M13 to bind the core antigen of lipopolysaccharide (LPS), enabling binding to a variety of top-priority pathogenic gram-negative bacterial species, including E. coli, P. aeruginosa, A. baumannii, Klebsiella pneumoniae, and Burkholderia cepacia. Since the anti-LPS phages are able to bind but do not infect (nonviable), they are not cytotoxic by themselves. However, delivery of PMB by the anti-LPS phage confers antibiotic activity. Thus, in our strategy, PMB molecules are conjugated to the anti-LPS phage capsid, and delivered specifically to gram-negative bacterial cells through the specificity and high affinity of the anti-LPS binding domain. We have shown that the PMB – anti-LPS phage conjugate (termed “PMB–Phage” hereafter) effectively lowers the minimal inhibitory concentration of PMB by multiple orders of magnitude in vitro compared to PMB sulfate. MIC and MBC of PMB and PMB-Phage, determined in vitro for several gram-negative organisms. The heat map corresponds to the MIC or MBC values. Equivalent PMB concentrations for PMB-Phage MIC and MBC were calculated from the measured phage concentration and the average amount of PMB loaded per virion. * = resistant. ND = not determined due to technical limitation on phage concentration. Results We have already demonstrated following results.A broad-spectrum anti-LPS phage was engineered and verified to bind to several gram-negative bacterial species including E. coli.Polymyxin B was conjugated to the anti-LPS phage, creating PMB-Phage, which was highly antibacterial in vitro.PMB-Phage is non-toxic to mammalian cells in vitro and non-toxic in mice.PMB-Phage is distributed to various organs within 1 hour and has an elimination half-life of approximately 1 day.PMB-Phage appears to be effective in treating E. coli bacteremia in a mouse model. PMB-Phage Biodistribution Figure 9: Time course biodistribution of PMB-Phage in various organs, over time in male mice with (red) or without (blue) 1×10^7cfu (non-lethal dose) of E. coli ATCC BAA 1161 injected (n=3). Signals are measured as a percentage of the injected dose (ID) per volume (per cc). Representative biodistribution images (j) of 1 animal. Conclusion PMB-Phage will greatly reduce the nephrotoxicity of PMB, enabling safe treatment for a broader patient population. Liver and kidney blood biomarkers at end point of 7-day toxicity studies. Animals in experimental groups were injected 100µL of test materials through IV tail vein injection daily for 7 consecutive days. Experimental group animals for each condition (N=3), receiving either PMB or PMB-Phage at different doses show no significant difference comparing to control groups of animals group receiving no treatment (N=5) and 1xPBS buffer (N=3), in light and dark grey columns respectively. The only exception being all animals receiving 72 mg/kg body weight PMB (N=3) did not survive a single dose and died on day 1 (indicated by red cross in figure). Disclosures All Authors: No reported disclosures

Cellulose Nanofiber-Reinforced γ-AlOOH Aerogels for Enhanced Removal of Environmental Pollutants.

In this study, we report the modification of a monolithic γ-aluminum oxy-hydroxide (γ-AlOOH) aerogel with cellulose nanofibers (CNFs) using the sol-gel method via supercritical drying. The optimized 2% CNF (w/w) results in a monolithic CNF-γ-AlOOH that is amorphous in nature, along with C-C and C-O-C functional groups. Transmission electron microscopy (TEM) images of the as-synthesized CNF-γ-AlOOH showed CNF embedded in the γ-AlOOH aerogel. The adsorption capacities were determined using azo dyes: methylene blue (MB) and crystal violet (CV), and heavy metal ions: lead [Pb(II)], uranium [U(VI)], and arsenic [As(III)] as models for environmental pollutants. The maximum adsorption capacities were 210 mg/g for CV, 204 mg/g for MB, 105 mg/g for As(III), and 339 mg/g for U(VI) at a pH of 7, whereas Pb(II) exhibited a maximum adsorption capacity of 100 mg/g at pH 5. This is attributed to the synergistic interactions between the CNF hydroxyl groups and γ-AlOOH active sites, facilitating electrostatic and coordination interactions. The as-synthesized aerogels demonstrated high recyclability, retaining over 94% adsorption efficiency after five cycles and offering a sustainable approach to environmental remediation. These findings establish CNF-γ-AlOOH aerogels as robust, eco-friendly materials for water treatment applications, with potential scalability for addressing diverse environmental pollutants. Future research should explore their application in the removal of emerging contaminants and optimize their synthesis for household and industrial-scale implementation.