Microscopy Research and Technique最新文献

Skin problems are a serious condition that affects people all over the world. Prolonged exposure to ultraviolet rays' damages melanocyte cells, leading to the uncontrolled proliferation of melanoma, a form of skin cancer. However, the dearth of qualified expertise increases the processing time and cost of diagnosis. Early detection of melanoma in dermoscopy images significantly enhances its chance of survival. Pathologists benefit substantially from the precise and efficient melanoma cancer diagnosis using automated methods. Nevertheless, the diagnosis of melanoma has consistently been a challenging procedure due to the imbalance images and limited data. Our objective was to employ a novel deep method to diagnose melanoma from dermoscopic images automatically. The research has proposed a novel framework for detecting skin malignancies. The proposed plan, which includes CNN, DenseNet, a batch normalization layer, maxpooling, and a ReLU layer activation function, solves the overfitting problem well. Furthermore, we used a large number of samples for testing and effectively employed data augmentation to prevent any issues related to class imbalance. The Adam optimizer is the most efficient deep learning optimizer for addressing challenges associated with large datasets, such as lengthy processing times. This is due to its specifically designed algorithm. Experiments ensure that the proposed framework achieved 95.70% micro average accuracy on the ISIC-2019 dataset and 93.24% accuracy on the HAM-10000 dataset. Comprehensive evaluation and analysis were used to evaluate our framework's performance. The results show that the proposed approach performs better with cross-validation by 94.8% accuracy than the most sophisticated deep learning-based technique. During studies, medical professionals will employ the proposed model to identify skin cancer in its early stages.

It is known that the interaction between electron beam and material surface enables a variety of physical phenomena, which hold significant inspiration for functional application. Herein, the process of in situ surface exsolution was observed and documented for the basalt phase in the Chang'e-5 lunar samples via scanning electron microscopy. Energy dispersive x-ray spectroscopy analysis confirmed the main existence of metal oxides such as plagioclase and pyroxene. Under electron beam irradiation, these components have undergone in situ dynamic mass loss and radiation decomposition, leading to an interesting in situ surface exsolution, as the energy of the electron beam exceeds the dissociation energy of metal-oxide bonds. It is clarified that the thermal effect of the electron beam is negligible under the experimental conditions. Alternatively, the “trinity” of electron beam-induced electric field-radiolysis-electron beam deposition is the key factor driving the surface exsolution. Our result not only deepens our understanding of the physical and chemical properties of lunar soil but also lays the groundwork for future applications of lunar soil for functional application.

Pollen content analysis of honey provides insight into the diversity of pollen grains and the development of a seasonal calendar to identify the diversity and availability of melliferous flora around the year. Melissopalynology is the most primitive and widely used technique for the qualitative and quantitative pollen profiling of honey. The honey of Azad Kashmir Pakistan has never been analyzed for pollen content despite the production at an industrial scale. A total of 60 samples were analyzed for the types and frequency of melliferous flora by the use of light microscopy and scanning electron microscopy. A wide diversity in morphological features differentiated 92 plant species belonging to 48 families. The most frequent plant families observed were Fabaceae, Poaceae, Asteraceae, Myrtaceae, Rosaceae, Betulaceae, and Buxaceae. Asteraceae showed the maximum species contribution. The obtained percentages of representative pollens were classified in frequency classes as follows: D: Predominant pollen (45%), S: Secondary Pollen (15%–45%), I: Important minor pollen (3%–15%), and M: Minor pollen (1%–3%). Most of the samples were multifloral containing not one dominant pollen, while one was bifloral containing two dominant pollen types and one was unifloral containing only one dominant pollen. The results reflect the melliferous potential of the native flora in the region. Indigenous floral resources from tropical vegetation to alpine meadows sustain bee colonies even during dearth periods. This work will benefit consumers, beekeepers, and regulatory bodies to maintain the authenticity of honey by the provenance of geographical and botanical origin.

Selenium nanoparticles (SeNPs) have garnered significant interest as anticancer and antimicrobial agents. The aqueous extract of medicinal plant Drimia indica leaves (DI-LAE) was used to synthesize SeNPs (DI-SeNPs) that were extensively characterized by UV–visible absorbance, TEM, EDX, XRD, zeta potential measurements, and FTIR. DI-SeNPs exhibited dose-dependent toxicity against the human lung adenocarcinoma cell line (A549; IC₅₀ of 43.21 μg/mL). DI-SeNPs increased reactive oxygen species (ROS) generation in A549 cells. DI-SeNPs caused cell cycle arrest in the G2/M phase and increased DNA damage in A549 cells, ultimately driving these cells toward apoptosis. DI-SeNPs significantly increased p53 levels, decreasing Akt levels and elevating cleaved caspase 3 levels in A549 cells. Additionally, DI-SeNPs exhibited antimicrobial activity against various bacteria and fungi. These findings suggest that DI-SeNPs possess significant anticancer and antimicrobial properties, mediated through mechanisms involving ROS generation, cell cycle arrest, and apoptosis induction.

The architecture of the avian oropharynx corresponds to the feeding pattern. The present study aims to provide data on morphology, morphometry, and spatial distribution of taste buds in the oropharyngeal floor of the northern bobwhite (Colinus virginianus) using gross anatomy, morphometric, and scanning electron microscopy. The lower beak tip and tomia revealed the presence of variably-sized dermal papillae. The prefrenular part of the oral floor had an interrupted median groove. Numerous taste buds and rostral submandibular salivary gland openings were detected alongside this groove. The tongue partially filled the oral floor. Its rostral end formed a median pointed process, the lingual nail. The dorsolateral aspects of the lingual apex and body showed hair-like and rosette-shaped filiform papillae of variable densities and sizes. However, these parts were devoid of taste buds. On the other hand, the surface mucosa of the lingual root presented numerous scale-like cellular elevations and a large number of taste buds. Examination of cross sections in the lingual root suggested the presence of two groups of caudal lingual salivary glands, central and lateral. The laryngeal mound contained taste buds that protruded from the surface epithelium into the lumen. The mucosa of the pharyngeal floor contained many taste buds that appeared similar to those detected on the laryngeal mound, except for the large taste pores, excessive cellular porosity, and denser microvilli. The total proportions of the taste buds in the oral and pharyngeal floors were 34.1% and 65.81%, respectively. The proportions of taste buds were 34.1%, 57.26%, 4.27%, and 4.27% in the sublingual floor, lingual root, laryngeal mound, and pharyngeal wall, respectively. In conclusion, this study provides comprehensive data on the oropharynx of northern bobwhite and will help to understand mechanisms governing food gustation in the studied bird and other related birds.

Analysis of indentation data of heterogeneous material, in particular, layer on an elastic substrate requires information about the contact area that is essential for calculating mechanical properties. The actual shape of the AFM-tip is not described by simple body of revolution. In this work, the indentation of a stiff layer on a hyperelastic substrate by a truncated conical tip is studied using finite element methods. The size of the tip, elastic modulus, and thickness of the layer are varied. The obtained model dependences of loading and contact area versus the depth of indentation are used in analysis of the experimental data of AFM indentation of stiff inhomogeneous nanolayers of polyurethane surface. Thickness and elastic modulus of the layers, fracture properties of the surface are studied. The obtained results can find application in the study of mechanical properties and fracture toughness of thin flexible films on an elastic substrate.

Currently, nanotechnology (NT) and nanoparticles (NPs) have gained significant attention in the scientific field due to their diverse application history. Particularly, in environmental applications, their antibacterial efficiency in fisheries due to antibacterial resistance. However, the NPs have been found toxic in the environment. Therefore, the current study aimed to fabricate less toxic NPs using environmentally dried leaves to check their antibacterial efficacy and possible toxicity against grass carp. The findings confirmed the good dispersity of obtained AgNPs, which further showed promising antibacterial activity against several bacterial isolates including Staphylococcus with a zone of inhibition (23.73 ± 0.57 nm). Also, the AgNPs were exposed to the grass carp (Ctenopharyngodon idella) for possible toxicity and toxic effects. First, the bioaccumulation of AgNPs was significantly observed in gills followed by intestines and muscles (p < 0.05). Finally, the AgNPs mainly accumulate in the liver, followed by the intestine, gills, and muscles. Additionally, the deposition of AgNPs in various organs resulted in histological alteration such as necrosis and infiltration of red blood cells in the intestine and the fusion of gill lamella. Hence, the synthesized NPs using dried leaf extract could be a promising approach in applied science. The significant features of the nanoparticles in the present work using green synthesis can help in synthesizing less toxic materials.

As a flexible biomolecule, the spatial structure of DNA is variable. The effects of concentration, metal cations, and low pH on DNA morphology were studied. For the high concentration of DNA, the cross-linked branch-like or network structures were formed. For the low concentration of DNA, isolated, random and freely loose linear DNA chains were presented. These phenomena were related to the intermolecular interactions. Branch-like DNA structures were reformed with the addition of metal cations to the low concentration of DNA at pH 7–4, suggesting the negative charges of DNA were neutralized, thus transforming the spatial structure of DNA into a low charge density morphology and presenting the hypochromic effect. Compared to the monovalent alkaline metal cations, more negative charges of DNA were screened by the alkaline-earth metal cations. Distinct DNA morphologies were observed for pH 3. The linear and condensed DNA structures were simultaneously observed, which was met regardless of the solution with or without the addition of metal cations. This was further confirmed by the absorbance of DNA. Compared to the pure DNA, bulky and aggregated DNA collapsed structures were formed when the sodium and magnesium cations were added to the reaction solution. In addition, it was verified that the condensed DNA structures failed to revert back to the chain structure by neutralizing acidic solutions with alkali, but the compacted DNA spheres became loose. The conductivities of various DNA morphologies were measured. They were morphology-dependent. This study provides guidance for the behavior of DNA in the acidic solutions and further promotes the application of DNA in DNA-based nano-optoelectronic devices.