Bright-field Microscopy Research Articles

Comparative investigation of fillers loading effect on morphological, micromechanical, and thermal properties of polyvinyl alcohol/cellulosicfillers-based composites

Polyvinyl alcohol (PVA)-based biocomposites were fabricated by the incorporation of chitosan (Ch), cellulose fibers (CS), and their mixture (1:1 ratio). Fillers with various loading (2, 4, 8, and 10 wt.-%) were incorporated into PVA employing the solution casting method. The fillers and biocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), brightfield microscopy, tensile and microindentation tests, contact angle measurement and thermogravimetric analysis (TGA). FTIR spectra revealed the removal of lignin, and intermolecular H-bonding between PVA and fillers promoting their filler–matrix interfacial interactions. Crystallographic results showed varied crystallite sizes and crystallinity of composites. Microscopic techniques revealed a uniform filler distribution, attributed to their compatibility with PVA. Tensile and microindentation tests demonstrated a decreased tensile strength (3.3–8.2 MPa of the composites compared to 15.7 MPa of the matrix) and Martens hardness (HM) of biocomposites. However, their value was increased with higher filler concentration, signifying the mechanical reinforcement. Contact angle analysis confirms the decreased wettability (hydrophilicity) of biocomposites, attributed to higher compatibility of fillers with PVA and intermolecular H-bonding between them. A slightly decreased thermal stability of biocomposites with filler incorporation is implied by TGA results despite their uniform distribution and strong matrix–filler interfacial interactions.

Histo-anatomical features of garden lupin (lupinus polyphyllus lindl.)

Lupinus polyphyllus Lindl. (garden lupin, large-leaved lupin) is a perennial herbaceous legume, used for ornamental purposes, for improving soil quality, as forage or in human food products. However, little is known about anatomical features this species’Lupin vegetative organs (roots, petioles, leaf blades) were collected, cross sectioned and analyzed by bright-field microscopy. Lupin roots showed primary and incipient secondary structures, with a cortex featuring large-sized cells with rich cellular content and granular solid inclusions. Leaf petioles had rare peltate hairs and large sub-stomatal lacunes, a large medullary lacune and rich parenchyma. Leaf blades had typical bifacial structure, with three-layered palisade tissue and less proeminent midrib, with a collateral bundle, protected by small caps of collenchyma. Bangladesh J. Bot. 53(3): 423-428, 2024 (September)

Review of In Situ Hybridization (ISH) Stain Images Using Computational Techniques.

Recent advancements in medical imaging have greatly enhanced the application of computational techniques in digital pathology, particularly for the classification of breast cancer using in situ hybridization (ISH) imaging. HER2 amplification, a key prognostic marker in 20-25% of breast cancers, can be assessed through alterations in gene copy number or protein expression. However, challenges persist due to the heterogeneity of nuclear regions and complexities in cancer biomarker detection. This review examines semi-automated and fully automated computational methods for analyzing ISH images with a focus on HER2 gene amplification. Literature from 1997 to 2023 is analyzed, emphasizing silver-enhanced in situ hybridization (SISH) and its integration with image processing and machine learning techniques. Both conventional machine learning approaches and recent advances in deep learning are compared. The review reveals that automated ISH analysis in combination with bright-field microscopy provides a cost-effective and scalable solution for routine pathology. The integration of deep learning techniques shows promise in improving accuracy over conventional methods, although there are limitations related to data variability and computational demands. Automated ISH analysis can reduce manual labor and increase diagnostic accuracy. Future research should focus on refining these computational methods, particularly in handling the complex nature of HER2 status evaluation, and integrate best practices to further enhance clinical adoption of these techniques.

Quantification of Acanthamoeba spp. Motility.

Acanthamoeba keratitis is a severe ocular infection that poses treatment challenges and can lead to blindness. Despite its ubiquity and potential contamination of contact lenses after water exposure, the natural behavior of this pathogen remains elusive. Understanding Acanthamoeba's movement patterns can inform us about how it colonizes contact lenses and contaminates the patient's cornea. It is fortunate that Acanthamoeba spp. are visible via brightfield microscopy starting at 4x magnification. Previous techniques have been developed to quantify Acanthamoeba motility in regard to cytopathic effects or under-exposure to the electric field. Here, we describe a method to track and quantify Acanthamoeba spp. motility long-term (hours to days), which is a protocol applicable to multiple amoeba strains, surfaces, and nutritional status of amoeba. This procedure is germane to determining many core motility quantifications, such as distance, speed, confinement, and directionality, which are necessary to monitor different stages of infection, proliferation, or behavioral change.

Ultrastructural study of pollen and tapetum development in Hydrocleys nymphoides, Alisma plantago-aquatica, and Sagittaria montevidensis (Alismataceae).

The Alismataceae family, widely distributed across tropical temperate swamps and wetlands, includes 15 genera post-merger with Limnocharitaceae. In Argentina, six genera are represented across three clades. Embryological characters, notably the male gametophyte and anther, are crucial in taxonomy due to their stability against environmental changes. This study aims to analyze the ultrastructure of the tapetum and pollen grain development in three economically and ecologically important species representing each clade: Sagittaria montevidensis (Clade A), Hydrocleys nymphoides (Clade B), and Alisma plantago-aquatica (Clade C). Anthers at different developmental stages were processed according to classic techniques for their observation with bright-field and transmission electron microscopy. The three studied species within the Alismataceae family exhibit similar reproductive characteristics. Seven stages of pollen grain development were identified. The microsporogenesis is successive with a regular meiosis. The ultrastructure of the tapetal cells shows similarities to other species with plasmodial tapetum. During the microspore tetrad stage, there is tapetal hyperactivity and an increase in secretion processes. In the free microspore stage, the tapetal cells lose their walls and increase the amount of rough endoplasmic reticulum forming a network of cisternae that extend into evaginations. Later cells completely invade the anther locule and fuse to form a tapetal plasmodium. No peritapetal membrane with orbicules was observed. Pollen is released at the tricellular stage. The pollen grain wall presents an ectexine with a basal layer, columellae, and tectum with supratectal spines while an endexine is not observed in any of the three species. This research enhances the understanding of tapetal cell interactions with developing pollen grains and contributes to the knowledge of the ultrastructure of plasmodial tapetum. Moreover, these findings highlight evolutionary reproductive patterns in Alismataceae, suggesting the plasmodial tapetum as a synapomorphy for the order.

CYTOSKELETON DYNAMICS AND SPATIAL ORGANIZATION DURING EPITHELIAL-TO-MESENCHYMAL TRANSITION

Epithelial-to-mesenchymal transition (EMT) is a crucial process that occurs during normal development, such as embryogenesis and organ formation. If it is inappropriately activated, it can lead to pathological processes like metastasis. Although EMT is well studied at the morphological and transcriptome level, cytoskeleton changes during this process are less understood. In our work we aimed to describe the morphological changes that occurred in MCF-7, A-549 and HaCaT cells after EMT, analyze microtubule dynamics, spatial distribution and its contribution to cell motility, identify changes in actin filament organization and study focal adhesion turnover in the cells after EMT. We hypothesized that the dynamics of microtubules in cells undergoing EMT might change. Cells undergoing EMT were expected to have more dynamic microtubules. Also, cells undergoing EMT are expected to adhere more efficiently to diverse substrates, and therefore spread and move more easily. Focal contacts in cells undergoing EMT were expected to be more pronounced and dynamic than in cells that not undergoing EMT. The research methods used in the study included inducing EMT in modified MCF-7 cells through an inserted inducible Tet-on system and stimulation of EMT in A-549 and HaCaT cells using TGF-β. The cells were observed using bright field microscopy, and immunofluorescence analysis was conducted to visualize microtubules and actin filaments. Transfection with EB-3–RFP protein was done to describe and measure microtubule dynamics, while transduction with Talin-RFP and transient transfection with Ptag-RFP-vinculin was done to visualize focal adhesions. Time-lapse fluorescent microscopy was used to record films, and the Fiji Image J program was used to analyze the data. All statistical analysis was performed using GraphPad Prism (Dotmatics, USA), and a nonparametric Mann-Whitney U test or parametric t-test with Welch correction. The actin filament measurements were completed using Matlab scripts. The major research findings: In all three-cell models after EMT, cell morphology changed. Cells increased in size. MCF-7 and HaCaT became spread out, while A-549 became elongated. Some of the cells lost cell-cell contacts. All three cell models after EMT had alterations in microtubule organization and dynamics. MCF-7 and HaCaT cells showed more frequently individual MTs at cell edges, while A-549 had less covered nucleus by MTs after EMT. Microtubule dynamics (growth velocity) increased, and the length of microtubule growth tracks became longer. The average angle of MT growth trajectories to cell radius decreased. Actin fibers rearranged into more pronounced stress fibers after EMT. Alterations in the focal adhesion behaviors were different in three models used. These results indicate that cytoskeletal changes during EMT mainly include increased microtubule dynamics.

Practical guidelines for cell segmentation models under optical aberrations in microscopy

Cell segmentation is essential in biomedical research for analyzing cellular morphology and behavior. Deep learning methods, particularly convolutional neural networks (CNNs), have revolutionized cell segmentation by extracting intricate features from images. However, the robustness of these methods under microscope optical aberrations remains a critical challenge. This study evaluates cell image segmentation models under optical aberrations from fluorescence and bright field microscopy. By simulating different types of aberrations, including astigmatism, coma, spherical aberration, trefoil, and mixed aberrations, we conduct a thorough evaluation of various cell instance segmentation models using the DynamicNuclearNet (DNN) and LIVECell datasets, representing fluorescence and bright field microscopy cell datasets, respectively. We train and test several segmentation models, including the Otsu threshold method and Mask R-CNN with different network heads (FPN, C3) and backbones (ResNet, VGG, Swin Transformer), under aberrated conditions. Additionally, we provide usage recommendations for the Cellpose 2.0 Toolbox on complex cell degradation images. The results indicate that the combination of FPN and SwinS demonstrates superior robustness in handling simple cell images affected by minor aberrations. In contrast, Cellpose 2.0 proves effective for complex cell images under similar conditions. Furthermore, we innovatively propose the Point Spread Function Image Label Classification Model (PLCM). This model can quickly and accurately identify aberration types and amplitudes from PSF images, assisting researchers without optical training. Through PLCM, researchers can better apply our proposed cell segmentation guidelines. This study aims to provide guidance for the effective utilization of cell segmentation models in the presence of minor optical aberrations and pave the way for future research directions.

Simultaneous enumeration of yeast and bacterial cells in the context of industrial bioprocesses

Abstract In scenarios where yeast and bacterial cells coexist, it is of interest to simultaneously quantify the concentrations of both cell types, since traditional methods used to determine these concentrations individually take more time and resources. Here, we compared different methods for quantifying the fuel ethanol Saccharomyces cerevisiae PE-2 yeast strain and cells from the probiotic Lactiplantibacillus plantarum strain in microbial suspensions. Individual suspensions were prepared, mixed in 1:1 or 100:1 yeast-to-bacteria ratios, covering the range typically encountered in sugarcane biorefineries, and analyzed using bright field microscopy, manual and automatic Spread-plate and Drop-plate counting, flow cytometry (at 1:1 and 100:1 ratios), and a Coulter counter (at 1:1 and 100:1 ratios). We observed that for yeast cell counts in the mixture (1:1 and 100:1 ratios), flow cytometry, the Coulter counter, and both Spread-plate options (manual and automatic CFU counting) yielded statistically similar results, while the Drop-plate and microscopy-based methods gave statistically different results. For bacterial cell quantification, the microscopy-based method, Drop-plate, and both Spread-plate plating options and flow cytometry (1:1 ratio) produced no significantly different results (P > 0.05). In contrast, the Coulter counter (1:1 ratio) and flow cytometry (100:1 ratio) presented results statistically different (P < 0.05). Additionally, quantifying bacterial cells in a mixed suspension at a 100:1 ratio wasn't possible due to an overlap between yeast cell debris and bacterial cells. We conclude that each method has limitations, advantages, and disadvantages.

Exploring the Cutting Process of Coaxial Phase Change Fibers under Optical Characterization Tests

Urban heat islands (UHI) are a growing issue due to urbanization, causing citizens to suffer from the inadequate thermal properties of building materials. Therefore, the need for climate-resistant infrastructure is crucial for quality of life. Phase change materials (PCMs) offer a solution by being incorporated into construction materials for thermoregulation. PCMs store and release heat as latent heat, adjusting temperatures through phase changes. Polymeric phase change fibers (PCFs) are an innovative technology for encapsulating PCMs and preventing leaks. This study produced PCFs via wet-spinning, using commercial cellulose acetate (CA, Mn 50,000) as the sheath and polyethylene glycol (PEG 2000) as the core. The PCFs were cut using a hot-cutting method at three different temperatures and washed with distilled water. Morphological analysis was conducted with a bright-field microscope, and chemical analysis was performed using Fourier transform infrared spectroscopy (FTIR) before and after controlled washing. Additionally, the washing baths were analyzed by UV-visible spectroscopy to detect PEG. The PCFs displayed a well-defined core-shell structure. Although some PEG 2000 leakage occurred in unsuccessful cuts, cuts at 50 °C showed sealed ends and less material in the baths, making it viable for civil engineering materials.

White Light Diffraction Phase Microscopy in Imaging of Breast and Colon Tissues.

This paper reports results obtained using white light diffraction phase microscopy (wDPM) on captured images of breast and colon tissue samples, marking a contribution to the advancement in biomedical imaging. Unlike conventional brightfield microscopy, wDPM offers the capability to capture intricate details of biological specimens with enhanced clarity and precision. It combines high resolution, enhanced contrast, and quantitative capabilities with non-invasive, label-free imaging. These features make it a useful tool for tissue imaging, providing detailed and accurate insights into tissue structure and dynamics without compromising the integrity of the samples. Our findings underscore the potential of quantitative phase imaging in histopathology, in the context of automating the process of tissue analysis and diagnosis. Of particular note are the insights gained from the reconstructed phase images, which provide physical data regarding peripheral glandular cell membranes. These observations serve to focus attention on pathologies involving the basal membrane, such as early invasive carcinoma. Through our analysis, we aim to contribute to catalyzing further advancements in tissue (breast and colon) imaging.

A Simple Method for Visualization and Quantitative Evaluation of Single and Collective Cell Migration in Bright Field Microscopy Images

Cell migration is observed in various cases such as embryonic and lesion developments. The migration directly influences the phenomena around the migration path. Bright field microscopy, generally used for cell observation, is effective in tracking cell movement, but the detection of the cell outline via image processing methods partially fails. In this study, a simple method, utilizing the intensity fluctuation of the image caused by the passage of a cell as a parameter for evaluation of the cell movement, has been proposed to visualize the region where the cell passed and quantitatively evaluate its frequency by the fluctuation pattern. The map that depicts the activity of cell movement is created, and the geometrical characteristics of each region and fluctuation degree are quantitatively shown. Because detection of the cell outline is not necessary, this method is applicable to collective cells as well as single cells. When this method was applied to the images of hemocytes inHalocynthia roretzi(Ascidiacea), which were composed of single and collective cells and showed complex patterns in movement, the map and quantitative parameters for the fluctuation were successfully obtained. The method can be improved by the calibration of intensity distribution and applied to cells in various species.

Full-field optical coherence microscopy enables high-resolution label-free imaging of the dynamics of live mouse oocytes and early embryos

High quality label-free imaging of oocytes and early embryos is essential for accurate assessment of their developmental potential, a key element of assisted reproduction procedures. To achieve this goal, we propose full-field optical coherence microscopy (FF-OCM), constructed as a compact module fully integrated with a commercial wide-field fluorescence microscope. Our system achieves optical sectioning in wide-field, high in-plane resolution of 0.5 µm, and high sensitivity to backscattered light. To demonstrate its imaging capabilities, we study live mouse oocytes and embryos at all important stages of meiotic maturation and early embryogenesis. Our system enables visualization of intracellular structures, which are not visible in common bright-field microscopy, i.e., internal structure of nuclear apparatus, cytoskeletal filaments, cellular cortex, cytoplasmic protrusions, or zona pellucida features. Additionally, we visualize and quantify intracellular dynamics like cytoplasmic stirring motion, nuclear envelope fluctuations and nucleolus mobility. Altogether, we demonstrate that FF-OCM is a powerful tool for research in developmental biology that also holds great potential for non-invasive time-lapse monitoring of oocyte and embryo quality in assisted reproduction.

Ultraplex microscopy: versatile highly-multiplexed molecular labeling and imaging across scale and resolution.

The molecular organization of cells and tissue is challenging to study due to the inefficiency of multiplexed molecular labeling methods and the limited options for combining microscopy modalities in a single specimen, especially when high spatial resolution is needed. Here we describe ultraplex microscopy, which combines serial multiplexing, ultrathin sectioning, and reversible embedding to circumvent incompatibilities between labeling and imaging techniques, enhance resolution, and expand multiplexing capacity within and across modalities. Samples can be labeled with antibodies, RNA probes, and tissue stains for imaging by brightfield, epifluorescence, super-resolution, and electron microscopy without specialized reagents or materials. We demonstrate applications in brain tissue including molecular profiling of single cells and axonal boutons, high-resolution molecular colocalization, and correlative imaging of fluorescent proteins with confocal and ultraplex microscopy. The power and versatility of ultraplex microscopy will be valuable in addressing currently intractable experimental questions in many systems and contexts.

Copper-induced pro-apoptotic response and its alleviation by Quercetin through autophagic modulation in HEPG2 cells

BackgroundRecent studies indicated that the liver is susceptible to Cu-induced stress as it stores and distributes the metal to other cellular organelles. To counteract the hepatocytic damage, a known polyphenol, quercetin, was employed for its remarkable antioxidant properties. Thus, the study aimed to assess quercetin’s potency against Cu-induced toxicity in HEPG2 cells. MethodsThe cellular viability of HEPG2 cells was carried out by MTT assay. All the cellular experiments were divided into control, Cu 100 µM, Cu 100 µM (with Q μM), Cu 300 µM, Cu 300 µM (with Q 50 nM), and only quercetin (50 nM). Following this, reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were evaluated in co-exposure studies. Moreover, rhodamine-123, Hoechst stain, monodansylcadaverine (MDC), and acridine orange (AO) stain were used to visualize the morphological changes under bright field and fluorescent microscopy. Subsequently, western blotting was adopted to determine the expression level of apoptotic and autophagic marker proteins. ResultsCopper increased intracellular ROS, resulted in morphological abnormalities, nuclear condensation, and disrupted MMP. Moreover, Cu caused apoptotic cell deaths characterized by overexpressed pro-apoptotic proteins such as poly (ADP-ribose) polymerase (PARP), cysteine-dependent aspartate-specific proteases 3 (Caspase 3), and Bcl-2-associated X protein (Bax) and downregulated anti-apoptotic proteins such as B-cell lymphoma 2 (Bcl-2), respectively. However, quercetin restored overexpressed pro-apoptotic proteins and induced autophagosome-bound microtubule-associated protein light chain-3 (LC3II) conversion from LC3I. Furthermore, Cu-modulated autophagy marker proteins, including sequestosome-1 (p62), heat shock cognate proteins (Hsc 70, Hsc 90), lysosome-associated membrane protein (LAMP-2A), and AMP-associated protein kinase (AMPK). ConclusionThis study promotes the nutraceutical ability of quercetin to combat Cu-induced hepatotoxicity by understanding the intricate biological signaling pathways within cells.

Cross-modality sub-image retrieval using contrastive multimodal image representations

In tissue characterization and cancer diagnostics, multimodal imaging has emerged as a powerful technique. Thanks to computational advances, large datasets can be exploited to discover patterns in pathologies and improve diagnosis. However, this requires efficient and scalable image retrieval methods. Cross-modality image retrieval is particularly challenging, since images of similar (or even the same) content captured by different modalities might share few common structures. We propose a new application-independent content-based image retrieval (CBIR) system for reverse (sub-)image search across modalities, which combines deep learning to generate representations (embedding the different modalities in a common space) with robust feature extraction and bag-of-words models for efficient and reliable retrieval. We illustrate its advantages through a replacement study, exploring a number of feature extractors and learned representations, as well as through comparison to recent (cross-modality) CBIR methods. For the task of (sub-)image retrieval on a (publicly available) dataset of brightfield and second harmonic generation microscopy images, the results show that our approach is superior to all tested alternatives. We discuss the shortcomings of the compared methods and observe the importance of equivariance and invariance properties of the learned representations and feature extractors in the CBIR pipeline. Code is available at: https://github.com/MIDA-group/CrossModal_ImgRetrieval.

Robotic Ultrasound and Novel Collagen Analyses for Polycystic Kidney Disease Research Using Mice.

3D imaging and histology are critical tools for assessing polycystic kidney disease ( PKD ) in patients and animal models. Magnetic resonance ( MR ) imaging provides micron resolution, but is time consuming, expensive, and access to equipment and expertise is limiting. Robotic ultrasound ( US ) imaging has lower spatial resolution but is faster, more cost effective, and accessible. Similarly, Picrosirius red ( PSR ) staining and brightfield microscopy is commonly used to assess fibrosis; however, alternative methods have been shown in non-kidney tissues to provide greater sensitivity and more detailed structural characterization. In this study, we evaluated the utility of robotic US and alternative methods of quantifying PSR staining for PKD research. We compared longitudinal total kidney volume ( TKV ) measurements using US and MR. We additionally compared PSR imaging and quantification using standard brightfield with that by circularly polarized light with hue analysis, and fluorescence imaging analyzed using CT-FIRE software for automatic detection of individual collagen fibers. Increased TKV was detected by US in Pkd1RC/RC vs wild type ( WT ) at timepoints spanning early to established disease. US inter-observer variability was greater but allowed scanning in 2-5 minutes/mouse while MR required 20-30 minutes/mouse. While no change in fibrotic index was detected in this cohort of relatively mild disease using brightfield, polarized light showed fibers skewed thinner in Pkd1RC/RC vs WT. Fluorescence imaging showed a higher density of collagen fibers in Pkd1RC/RC vs WT, and fibers were thinner and curvier with no change in length. Additionally, fiber density was higher in both glomeruli and tubules in Pkd1RC/RC , and glomeruli had a higher fiber density than tubules in Pkd1RC/RC , and trended higher in WT. These studies show robotic ultrasound is a rigorous imaging tool for pre-clinical PKD research. Additionally, they demonstrate the increased sensitivity of polarized and fluorescence analysis of PSR-stained collagen.

Human Enteroid Monolayers: A Novel, Functionally-Stable Model for Investigating Oral Drug Disposition.

To further the development of an in vitro model which faithfully recapitulates drug disposition of orally administered drugs, we investigated the utility of human enteroid monolayers to simultaneously assess intestinal drug absorption and first-pass metabolism processes. We cultured human enteroid monolayers from three donors, derived via biopsies containing duodenal stem cells that were propagated and then differentiated atop permeable Transwell® inserts, and confirmed transformation into a largely enterocyte population via RNA-seq analysis and immunocytochemical (ICC) assays. Proper cell morphology was assessed and confirmed via bright field microscopy and ICC imaging of tight junction proteins and other apically and basolaterally localized proteins. Enteroid monolayer barrier integrity was demonstrated by elevated transepithelial electrical resistance (TEER) that stabilized after 10 days in culture and persisted for 42 days. These results were corroborated by low paracellular transport probe permeability at 7 and 21 days in culture. The activity of a prominent drug metabolizing enzyme, CYP3A, was confirmed at 7, 21, and 42 days culture under basal, 1α,25(OH)2 vitamin D3-induced, and 6',7'-dihydroxybergamottin-inhibited conditions. The duration of these experiments is particularly noteworthy, as this is the first study assessing drug metabolizing enzymes and transporters (DMET) expression/function for enteroids cultured for greater than 12 days. The sum of these results suggests enteroid monolayers are a promising ex vivo model to investigate and quantitatively predict an orally administered drug's intestinal absorption and/or metabolism. Significance Statement This study presents a novel ex vivo model of the human intestine, human intestinal organoid (enteroid) monolayers, that maintain barrier function and metabolic functionality for up to 42-days in culture. The incorporation of both barrier integrity and metabolic function over an extended period within the same model is an advancement over historically used in vitro systems, which either lack one or both of these attributes or have limited viability.

Generative AI for Cell Type-Specific Fluorescence Image Generation of hPSC-derived Cardiac Organoid.

Human pluripotent stem cell (hPSC)-derived cardiac organoid is the most recent three-dimensional tissue structure that mimics the structure and functionality of the human heart and plays a pivotal role in modeling heart development and disease. The hPSC-derived cardiac organoids are commonly characterized by bright-field microscopic imaging for tracking daily organoid differentiation and morphology formation. Although the brightfield microscope provides essential information about hPSC-derived cardiac organoids, such as morphology, size, and general structure, it does not extend our understanding of cardiac organoids on cell type-specific distribution and structure. Then, fluorescence microscopic imaging is required to identify the specific cardiovascular cell types in the hPSC-derived cardiac organoids by fluorescence immunostaining fixed organoid samples or fluorescence reporter imaging of live organoids. Both approaches require extra steps of experiments and techniques and do not provide general information on hPSC-derived cardiac organoids from different batches of differentiation and characterization, which limits the biomedical applications of hPSC-derived cardiac organoids. This research addresses this limitation by proposing a comprehensive workflow for colorizing phase contrast images of cardiac organoids from brightfield microscopic imaging using conditional Generative Adversarial Networks (GANs) to provide cardiovascular cell type-specific information in hPSC-derived cardiac organoids. By infusing these phase contrast images with accurate fluorescence colorization, our approach aims to unlock the hidden wealth of cell type, structure, and further quantifications of fluorescence intensity and area, for better characterizing hPSC-derived cardiac organoids.

Wear and neutron shielding resilience of titanium-hexagonal boron nitride coatings against extreme lunar radiation and thermal cycles

Ti6Al4V and Al6061 are aerospace alloys used in lunar structural components and rovers owing to their high specific strength. However, they deteriorate rapidly when subjected to demanding conditions of the lunar environment, such as extreme thermal cycles, solar particle radiation, and abrasive regolith. Cryo-milled powders were employed to deposit hBN-reinforced protective titanium coatings through plasma spray (atmospheric-APS and vacuum-VPS) with 2 and 10 vol% of hBN on Ti6Al4V and Al6061 substrates. These coatings were evaluated for durability under extreme lunar-like conditions, including thermal cycling, electron radiation, and synergistic (electron radiation-thermal cycle) exposure. The coatings exhibited radiation-induced hardening, resulting in a substantial increase in their microhardness ~20–40 % compared to virgin condition. Bright-field transmission electron microscopy (TEM) analysis reveals the presence of high dislocation densities, black dot defects, and dislocation clusters, providing evidence of the severe impact of synergistic environmental stresses. Ball-on-disk tribological tests were conducted in the presence of JSC-1 A lunar regolith simulant to evaluate the wear performance of coatings. Compared to conventional Ti6Al4V substrate, 50 %, 90 %, and 70 % reductions in wear volume were observed in the Ti/2 vol% hBN coatings in thermal-only, radiation-only, and synergistic environments. Neutron shielding tests indicate that the synergistic coatings offer higher neutron shielding performance by up to 28 % compared to virgin coatings, attributed to improved neutron capture by 10B isotopes. Upon a comprehensive assessment and ranking of multiple coatings under varying conditions, the VPS Ti/2 vol% hBN coating emerges as the top choice for protection against extreme radiation and thermal cycles for future lunar explorations.

The morphology of the pygidial glands and the chemical composition of their secretions of four sphodrine ground beetle species (Carabidae: Platyninae)

Ground beetles possess a pair of pygidial glands that produce and release secretions that play an important role in defense against predators. The morphology of these glands and the chemical composition of their products were studied in four species of the tribe Sphodrini: Calathus (Calathus) fuscipes (Goeze, 1777), C. (Neocalathus) cinctus Motschulsky, 1850, C. (N.) melanocephalus (Linnaeus, 1758) and Laemostenus (Antisphodrus) elongatus (Dejean, 1828). The morphological analyzes of the glands of the four taxa mentioned were carried out for the first time using bright-field and nonlinear microscopy. All morphological structures were precisely measured and photographed. The pygidial gland secretions of C. (C.) fuscipes and L. (A.) elongatus were analyzed for the first time using gas chromatography-mass spectrometry. A total of 30 compounds were detected from the extracts of pygidial gland secretions of the four Sphodrini species studied. The simplest chemical mixture was found in L. (A.) elongatus, while the most complex secretion was that of C. (C.) fuscipes. 1-Undecanol, which we were able to detect in all taxa examined here, and dodecyl butyrate, which was detected in the three Calathus species, have never before been detected in the secretions of ground beetles.