Microscopy Images Research Articles

Preparation and characterization of PVA/MWCNT nanocomposites: a composition dependence study of structural, optical and mechanical properties

This work investigates the properties of polyvinyl alcohol (PVA) nanocomposite films with varying multi-walled carbon nanotube (MWCNT) content, ranging from 2 to 8 wt.%. The films were prepared using a solution casting method and characterized using UV-visible spectroscopy, optical microscopy, X-ray diffraction, and tensile tests. The prepared PVA/MWCNT nanocomposite films exhibited optical band gap values ranging from 3.5 eV to 5.3 eV. XRD analysis confirmed the semi-crystalline nature of these nanocomposites. Mechanical properties, including hardness, yield strength, ultimate tensile strength, and Young’s modulus, were enhanced by increasing MWCNT content by up to 8%. Contact angle measurements showed an increase in hydrophobicity with increasing MWCNT content. Optical microscopy images revealed uniform dispersion of MWCNTs in the PVA matrix. These findings suggest potential applications of PVA-MWCNT nanocomposites in various fields, including photosensors, UV shielding, adjustable band gap devices, and flexible optoelectronic devices.

Breast cancer diagnostics by the intelligent analysis of white blood cells’ interaction with target cancer cells using convolutional neural networks

Interaction of immune system and cancer cells plays a crucial role in defining the physical and chemical characteristics of the tumor microenvironment. Consequently, monitoring and analyzing these interactions may prove essential for cancer diagnosis and prognosis. While standard techniques assessing cellular interaction are technically complicated and usually expensive, engineering solutions can be employed to introduce novel methods and effective techniques. In this paper, we presented a new blood-based breast cancer hallmark for people suspected of breast tumor disease (BTD) by time-lapse microscopy imaging from the interaction between the patient’s blood and MDA-MB-231 breast cancer cell lines. The detection protocol is based on the quantifying invasion of the WBCs to the breast cancer cell line. Many cytological, molecular, and immunofluorescent assays were carried out to approve the hypothesis. Blood immune cells showed meaningful invasion patterns to breast cancer cell lines in reverse correlation by the cancerous stage of the patients. Hence, we believe that the immune system is cognizant of the neoplastic nature of breast tumor disease. To eliminate all the human-related limitations, a convolutional neural network (CNN) architecture was used for invasion recognition. The proposed CNN architecture showed an accuracy of approximately 86%, making it a reliable, fast, and easy way for intelligent detection of invasion patterns to decide on the tumor stage. Results made us present the hypothesis that people with more aggressive breast cancer tumors have less strong immune cells to invade cancer cells which could be a start in the clinical use of the cellular-based immune system for cancer investigation. As WBCs were isolated from the blood with no pre-processing, this method would shed new light as a simple complementary method for better clarification of tumor nature.

Deep-learning assisted detection and quantification of (oo)cysts of Giardia and Cryptosporidium on smartphone microscopy images

Deep-learning assisted detection and quantification of (oo)cysts of Giardia and Cryptosporidium on smartphone microscopy images

Alleviating internal stress in diamond-like carbon films for enhanced tribological performance under high contact pressure via interface texturing

Diamond-like carbon (DLC) films have found widespread applications across numerous fields due to their exceptional properties. Nevertheless, their significant internal stress has restricted their further utility, particularly in scenarios involving high-contact pressure conditions. In response to this challenge, we fabricated diamond-like carbon films with nano-depth interface texture. This nano-depth interface texturing technique helps alleviate the internal stress within the carbon film, thereby enhancing the tribological performance of diamond-like carbon films with textured interfaces, especially under high contact pressure. We successfully fabricated textured carbon films with a thickness of 1 μm, which exhibited excellent tribological performance even under pressures exceeding 1 GPa. Through atomistic molecular dynamics simulations, internal stress testing, and cross-sectional transmission electron microscopy imaging, we observed that the incorporation of nano-depth interface texturing resulted in an approximate 47.62 % increase in the thickness of the transition layer between the silicon substrate and the carbon film. Furthermore, there was a notable reduction of about 30 % in the internal stress exhibited by the carbon films. These findings are expected to expand the application of carbon films under higher contact pressure and facilitate the production of thicker films.

Computer Vision Techniques for Morphological Analysis and Identification of Two Pseudo-nitzschia Species

The diversity of phytoplankton influences the structure of and processes that occur in marine ecosystems, with size and other morphological traits being crucial for nutrient uptake and retention in the euphotic zone. Our research introduces a machine learning method that can facilitate the analysis of phytoplankton functional traits from image data. We use computer vision to identify and quantify phytoplankton species and estimate size-related traits based on cell morphology. The study uses transfer learning, where generic, pre-trained YOLOv8 computer vision models are fine-tuned with microscope image data from the Adriatic Sea. The study shows that, for this task, it is possible to effectively fine-tune models trained on out-of-domain images and that this is possible with a small training dataset. The results show high accuracy in detecting and segmenting phytoplankton cells from the microscopic images of the two selected phytoplankton taxa. For detection, the model achieves AP scores of 88.1% for Pseudo-nitzschia cf. delicatissima and 90.9% for Pseudo-nitzschia cf. calliantha, while for segmentation, the scores are 88.4% for Pseudo-nitzschia cf. delicatissima and 91.2% for Pseudo-nitzschia cf. calliantha. Compared to manual image analysis, the developed automatic method significantly increases the number of samples that can be processed.

Structural, Thermal, Optical, Electrical, and Dielectric Properties of Complex Lead-Free Compound: [Bi1∕2Na1∕2][Fe1∕2W1∕2]O3

Some physical properties (structural, dielectric and optical) of a complex lead-free ceramic [[Formula: see text][Formula: see text]][[Formula: see text][Formula: see text]]O3 have been thoroughly examined in different experimental conditions in this study. It was fabricated via a solid-state reaction method. The crystal structure is monoclinic, according to the detailed analysis of the X-ray diffraction pattern. Also, the functional vibrational bands can be observed in the FT-IR and Raman spectra, which support the creation of the molecular structure. Scanning electron microscope (SEM) images of the sample clearly show the effects of [Formula: see text] and [Formula: see text] incorporation in morphology, and energy dispersive X-ray spectroscopy (EDX) indicates the existence of all constituents. The non-overlapping small polaron tunneling (NSPT) and correlated barrier hopping (CBH) model conduction mechanisms are examined through Jonscher’s power law. The contribution of the grain and grain boundary to the capacitive behavior is shown by Nyquist plots. According to a leakage current analysis, the compound exhibits Ohmic and space charge limited conduction (SCLC) conduction mechanisms. Electric field polarization was used to study the ferroelectric nature. The findings of this study show that the inclusion of [Formula: see text] and [Formula: see text] is an efficient technique to improve its dielectric and optical characteristics.

Quantifying pore spatial uniformity: Application on membranes before and after plasma etching

Membranes play a critical role in diverse applications, including filtration and tissue engineering. The importance of membrane performance optimization highlights the necessity of accurately characterizing the pore structure. Traditional Pore Size Distribution methodologies are widely used to quantify size uniformity. Uniformity though, integrates both size and spatial pore structure aspects, thus necessitating the synergy of complementary techniques to analyze pore structure. This work empowers classic pore metrology with stochastic geometry, specifically the Nearest Neighbour Index (NNI) to assess the spatial uniformity of pores in membrane Scanning Electron Microscopy (SEM) images. Through a comprehensive analysis of Polytetrafluoroethylene (PTFE) before and after plasma etching, along with nanofilament coated Polyethersulfone (PES) membranes, this analysis enhances our understanding of membrane morphology through pore structure and pore spatial arrangement. The findings indicate that increasing magnification leads to a decrease in apparent spatial uniformity, indicative of effects regarding the inclusion in analysis of families of finer pores. In almost all cases, NNI values show higher uniformity compared to a fully random scenario. Additionally, it is found that plasma etching does not have significant effects on spatial uniformity introducing only a slight uniformity in pore centroid arrangement, reflected in a small NNI increase. Furthermore, a pore area shuffling technique reveals the effects of pore density and size on spatial uniformity, highlighting patterns inherent to the materials under study.

SYNTHESIS OF MONO-DISPERSE MESOPOROUS SILICA-COATED MAGNETITE NANOPARTICLES FOR BIOSEPARATION

Magnetite nanoparticles (NPs) were synthesized using a cost-effective co-precipitation method. Magnetite NPs were encapsulated with silica via the modified Stober Method. Tetra ethyl ortho silicate (TEOS) was hydrolyzed and condensed with ethanol and H2O solution. Stable and biocompatible NPs were synthesized for biomedical applications such as bioseparation. This study expresses the NPs that can potentially be used in the bioseparation of toxic protein isolations and targeted drug delivery. X-ray diffraction verified the phase pattern having crystals like Fd-3[Formula: see text]m cubic space. Scanning electron microscopy (SEM) images identified the spherical-shaped NPs having size ranges from 15[Formula: see text]nm to 30[Formula: see text]nm for magnetite NPs and 20–40[Formula: see text]nm for silica-coated magnetite NPs. Fourier transform infrared spectroscopy (FTIR) confirmed the bond spectrum peak at 549[Formula: see text][Formula: see text] and 562[Formula: see text][Formula: see text] for magnetite NPs and silica-coated magnetite NPs, respectively. UV–Visible analysis observed the band absorptions above 250[Formula: see text]nm for magnetite and above 300[Formula: see text]nm for silica-coated magnetite NPs. This research suggests an easy way to use silica-coated Magnetite NPs for bioseparation at room temperature.

Morphology and crystallography of E-(Al18Cr2Mg3) nano dispersoids in 7475 Al alloy

The morphology and crystallography of E-(Al18Cr2Mg3) nano dispersoids in 7475 Al alloy have been studied by using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and electron tomography (ET). Seven distinct morphologies have been three-dimensionally distinguished at the nanoscale: (i) triangular plates on {111}Al, (ii) hexagonal plates on {111}Al, (iii) rods parallel to <110>Al, (iv) small tetrahedra with {111}Al facets, (v) small octahedra, (vi) spheres and (vii) irregular shapes. Twinning can contribute to the diverse morphologies of E nano dispersoids. The orientation relationships (ORs) between E nano dispersoids and Al matrix have been systematically investigated by selected area electron diffraction (SAED) patterns, HRTEM and matrix calculation. The results from the matrix calculation indicate the absence of clear ORs between E nano dispersoids and Al matrix in 7475 Al alloy.

Provably Trainable Rotationally Equivariant Quantum Machine Learning

Exploiting the power of quantum computation to realize superior machine learning algorithms has been a major research focus of recent years, but the prospects of quantum machine learning (QML) remain dampened by considerable technical challenges. A particularly significant issue is that generic QML models suffer from so-called barren plateaus in their training landscapes—large regions where cost function gradients vanish exponentially in the number of qubits employed, rendering large models effectively untrainable. A leading strategy for combating this effect is to build problem-specific models that take into account the symmetries of their data in order to focus on a smaller, relevant subset of Hilbert space. In this work, we introduce a family of rotationally equivariant QML models built upon the quantum Fourier transform, and leverage recent insights from the Lie-algebraic study of QML models to prove that (a subset of) our models do not exhibit barren plateaus. In addition to our analytical results we numerically test our rotationally equivariant models on a dataset of simulated scanning tunneling microscope images of phosphorus impurities in silicon, where rotational symmetry naturally arises, and find that they dramatically outperform their generic counterparts in practice. Published by the American Physical Society 2024

Role of Surface Tension on Heat Feedback and Power from Energetic Composites.

Heat feedback to the unburned reaction interface is an important controlling factor of the velocity of the reaction front and power delivery. In this paper, we investigate the effect of agglomerate surface tension and its relationship to surface residence time and heat feedback on the combustion characteristics by Si addition to an Al/KClO4 composite. Macroscopic imaging demonstrates a significant increase in burn rate with the addition of Si despite the fact that Si/KClO4 has a slightly lower energy density than Al/KClO4. Microscopic imaging coupled with three-color pyrometry reveals that molten liquid forms and evolves into spherical droplets on the burning surface, which are subsequently ejected from the surface. We find that the addition of Si results in a small increase in droplet size and a negligible impact on droplet temperature. However, the droplet formation rate on the surface is slower, leading to a significantly longer surface residence time. This leads to enhanced conductive heat feedback to the unburnt materials, thereby increasing the burn rate and energy release rate. We attribute the decreased droplet growth rate to the lowered surface tension of the liquid mixture with Si addition. This study highlights the crucial role of agglomerate physical property (e.g., surface tension) in influencing the combustion behavior of energetic composites.

Multi-scale study of the effect of superabsorbent polymers on microporosity, dimensional stability, and durability of cementitious materials

As internal curing agents, superabsorbent polymers (SAPs) help enhance the degree of hydration of cement particles. In the meantime, however, they affect the dimensional stability and durability of the mixtures that benefit from them. This critical aspect, which is influenced by the type, size, and dosage of SAPs, motivated the current study. To obtain holistic assessments and side-by-side comparisons, six high-performance mortar mixtures were developed based on a control mixture. The referenced mixtures contained two types, two sizes, and two dosages of SAPs. Initially, the performance characteristics of the SAP powders were determined, in terms of water absorption and desorption. Autogenous shrinkage tests were then performed to evaluate how SAPs contribute to controlling this type of shrinkage over time. The microstructures of the developed mixtures were then analyzed using mercury intrusion porosimetry, paired with scanning electron microscope images, providing fundamental insights into to the role of SAPs in both short and long terms. To correlate the findings to the mechanical properties of the developed mixtures, a set of compressive strength and abrasion resistance tests were performed. The results were then complemented with the data obtained from the rapid chloride migration tests. This study’s outcome showed that SAP particles can effectively reduce the development of autogenous shrinkage-induced strains. Additionally, the inclusion of SAPs was found to alter microstructural characteristics, increasing the density of the binding gel, while introducing capillary pores. This was confirmed through enhanced abrasion resistance and reduced chloride resistivity.

Surface roughness measurement using microscopic vision and deep learning

Due to the self-affine property of the grinding surface, the sample images with different roughness captured by the micron-scale camera exhibit certain similarities. This similarity affects the prediction accuracy of the deep learning model. In this paper, we propose an illumination method that can mitigate the impact of self-affinity using the two-scale fractal theory as a foundation. This is followed by the establishment of a machine vision detection method that integrates a neural network and correlation function. Initially, a neural network is employed to categorize and forecast the microscopic image of the workpiece surface, thereby determining its roughness category. Subsequently, the corresponding correlation function is determined in accordance with the established roughness category. Finally, the surface roughness of the workpiece was calculated based on the correlation function. The experimental results demonstrate that images obtained using this lighting method exhibit significantly enhanced accuracy in neural network classification. In comparison to traditional lighting methods, the accuracy of this method on the micrometer scale has been found to have significantly increased from approximately 50% to over 95%. Concurrently, the mean squared error (MSE) of the surface roughness calculated by the proposed method does not exceed 0.003, and the mean relative error (MRE) does not exceed 5%. The two-scale fractal geometry offers a novel approach to image processing and machine learning, with significant potential for advancement.

Tailoring the Molecular Structure of 6-Gingerol for Targeting the Phase Separation in Human Lysozyme.

Human lysozyme undergoes a phase-separation process to form insoluble amyloid-architects that cause several pathologies including systemic amyloidosis. Here we have tailored 6-gingerol by extending its molecular framework with active functional groups to specifically target lysozyme phase-transition events. Aggregation assay revealed that tailored 6-gingerol with 4-aromatic moieties (MTV4) substantially suppressed the conversion of the lysozyme low-density liquid phase (LDLP) to solid-phase structured amyloids. The data obtained from biophysical, computational, and microscopic imaging tools suggest direct intervention of MTV4 with the liquid-liquid phase separation. The CD data suggest that MTV4 was able to retain the native conformation of lysozyme. Both biomolecular and computational data reveal the interference of MTV4 with the aggregation-prone hydrophobic stretches within the lysozyme, thereby retaining the native structure and reversing the misfolded intermediates to active monomers. Also, MTV4 was able to induce rapid dissolution of preformed-toxic amyloid fibrils. These results reinforce the importance of the aromatic-aromatic interaction in preventing human lysozyme phase separation.

Muga (Antheraea assamensis) silk electrospun scaffold for biomedical applications

Abstract Wild silk varieties are less explored in the field of biomaterials than cultivated mulberry silk (Bombyx Mori). In the present work, an electrospun scaffold was produced from wild silk, muga (Antheraea assamensis), and it was assessed for the properties required for biomaterials. Scanning electron microscopy images showed that the electrospun fibers were formed without beads, and the majority of the fibers had diameters in the range of 500–900 nm. The scaffold started to decompose at 210 °C, which is higher than the temperature used for sterilization of the scaffold. The PBS uptake percentage was found to be 400 %, which is sufficient for the absorption of the medium used during cell culture. The scaffold had a hemolysis value of less than 5 %, which indicates that the scaffold exhibits good blood compatibility. The MTT assay showed cell viability of more than 80 % after 24 h and 48 h, and fluorescence microscopy showed that cells adhered and spread on the surface of the scaffold. The results show that muga silk electrospun mat can be used as an ideal biomaterial.

Influence of topography on nano-mechanical properties of cylindrical magnetron sputtered TiN films

Numerous studies on Nano-mechanical behavior of the thin films explained primarily in terms of their film morphology and particle size rather than film topography. Therefore, the current study investigates the effect of film topography on the nano-mechanical characteristics of the film. Ti/TiN multilayer thin films were deposited at varying deposition pressures by using an indigenously developed Cylindrical Magnetron Sputtering (CMS) unit. Surface crystallographic information is characterized by synchrotron-based Grazing Incidence XRD analysis. Film growth follows self-assembled nano hill architecture as revealed by AFM and in situ Scanning Probe Microscopy images. The tribo-mechanical properties of the film is dependent on the height and spacing of its self-assembled structure, which experiences either crushing or buckling under the indenter load, thereby affecting film characteristics. Film deposited at moderate pressure exhibits superior wear behavior, attributed to the interplay between Plasticity Index (PI) and Depth Recovery Ratio (DRR). The study primarily focused on film growth phenomena by using cylindrical targets and their influence on nanomechanical properties of the film.

Investigating the properties and agronomic benefits of onion peel and chicken feather-derived biochars

Biochar production from unconventional biomass, specifically onion peel (OP) and chicken feathers (CF), was investigated in this study. Two distinct biochars were produced by doping each biomass with the other, with the aim of exploring the synergistic effects of different feedstock combinations on biochar properties. The biochar production process was conducted using a retort heating method and characterized using several techniques. A yield of 36 % was obtained for OP-doped biochar (OP92CF8-BC) and 23 % for CF-doped biochar (F92OP8-BC). Fourier Transform Infrared Spectroscopy analysis revealed characteristic functional groups from cellulose, hemicellulose, and lignin in OP92CF8-BC, while CF92OP8-BC displayed keratin-related peaks. Scanning Electron Microscopy imaging showed surface morphology differences, with OP92CF8-BC exhibiting a rougher and more porous structure compared to CF92OP8-BC. Energy-Dispersive X-ray Spectroscopy analysis confirmed the elemental composition, with OP92CF8-BC having higher carbon, calcium, and sulfur contents and CF92OP8-BC having higher nitrogen and oxygen contents. The biochar had specific surface areas of 342.4 and 200.80 m2/g for OP92CF8-BC and CF92OP8-BC, respectively. According to the results, using biochar treatments-more especially, CF92OP8-BC-can significantly enhance cob weight. This could be good for agricultural productivity. These findings highlight the influence of feedstock composition on the properties of biochar and provide insights for its potential applications in soil amendment and pollutant removal.

Preparation of starch-based green nanofiber mats for probiotic encapsulation by electrospinning.

In this study, starch-based nanofiber mats were successfully prepared from aqueous solution by electrospinning and used for probiotic encapsulation for the first time. The physicochemical properties of the octenylsuccinated (OS) starch/poly(vinyl alcohol) (PVA) blend solutions were systematically investigated. Through Fourier transform infrared spectroscopy and X-ray diffraction spectra analysis, it was found that miscibility and hydrogen bonding interactions exist between OS starch and PVA molecules. Thermogravimetric analysis and derivative thermogravimetric analysis revealed that the produced nanofibers possess satisfactory thermal stability. Scanning electron microscopy images and diameter distribution histograms showed that continuous and defect-free nanofibers were obtained and along with the increase in the weight ratio of OS starch, the average diameter gradually decreased. In addition, it was confirmed that the probiotics were successfully encapsulated in nanofiber mats. The survival rates of Lactobacillus plantarum AB-1 and Lactobacillus rhamnosus GG encapsulated in nanofibers were as high as 94.63% and 92.42%, respectively, significantly higher than those of traditional freeze-drying. Moreover, compared to free cells, probiotics encapsulated in nanofiber mats retained better viability after 21 days of storage at 4 and 25°C, and showed remarkably higher survival rates after exposure to simulated gastric and intestinal fluid. This study showed that the developed nanofibers can be a promising encapsulation system for the protection of probiotics.

Choline and geranate ionic liquid for subgingival biofilm control

Periodontitis is a chronic inflammatory disease that causes destruction of the periodontium and eventual tooth loss. The priority in the periodontal treatment is to remove the subgingival biofilm. Chemical removal of biofilms using antimicrobial agents has been applied in clinical practice. However, their clinical effect is still limited because the agents must overcome biofilm’s significant drug tolerance, which is primarily caused by the extracellular matrix, a physical barrier that attenuates drug diffusion. This study aimed to study the use of ionic liquids (ILs), a new class of biocompatible materials, for controlling subgingival biofilms because of their excellent permeability. Choline and geranate (CAGE) IL was tested for its highly potent antiseptic behavior and permeability. Antibacterial tests revealed that the significant efficacy of CAGE against periodontopathic microorganisms was derived from their ability to destroy cell membrane, as demonstrated by membrane permeability assay and transmission electron microscopy imaging. Antibiofilm tests using two pathogenic biofilm models revealed that CAGE exerted efficacy against the biofilm-embedded bacteria, conspicuously neutralized the biofilms, and eventually destroyed the biofilm structure. Furthermore, the penetration of CAGE into the biofilm was visually confirmed using confocal laser scanning microscopy. This study highlighted the potential of CAGE as a powerful antibiofilm therapeutic.

Antimicrobial potential and characterization of silver nanoparticles synthesized from Ocimum sanctum extract

The growing resistance of microbes to conventional antibiotics and the environmental impact of chemical synthesis methods highlight the urgent need for effective and sustainable antimicrobial agents. In this study, we address these challenges by synthesizing silver nanoparticles (AgNPs) using Ocimum sanctum leaf extract, a green and efficient method. We confirmed AgNPs synthesis through UV-vis spectroscopy, observing a Surface Plasmon Resonance (SPR) peak centered at 420 nm. X-ray Diffraction (XRD) analysis showed intense peaks at 37.81°, 45.01°, 63.91°, and 78.0°, corresponding to Bragg's reflections at 111, 200, 220, and 311, respectively, with an average particle size of approximately 18 nm calculated using Scherrer's formula. The reduction of Ag+ was monitored using Atomic Absorption Spectroscopy (AAS), which revealed a rapid decrease from 2.73 ppm to 0.023 ppm within four minutes, driven by the active reducing agents in the O. sanctum extract. The Scanning Electron Microscope (SEM) image confirmed the spherical shape of the AgNPs, with an average size of 23.82 ± 4.17 nm. Fourier Transform Infrared (FTIR) spectroscopy identified absorption peaks at 1635 cm⁻¹ and 3430 cm⁻¹, associated with the amide I bond of proteins and OH stretching in alcohols and phenolic compounds, respectively. The synthesized AgNPs exhibited significant antimicrobial activity, demonstrated by a dose-dependent inhibitory effect against bacterial strains. The inhibition zone measured 6 mm at the lowest concentration of 5 µg/L and increased progressively to 14 mm at the highest concentration of 25 µg/L, indicating strong antimicrobial potential even at low dosages.