Micron最新文献

{"title":"Achieving an improved performance in double-sided friction stir weld joints by adjusting the welding conditions during the passes of AA6061-T6 aluminium alloy","authors":"Ankit Thakur,&nbsp;Varun Sharma,&nbsp;Navdeep Minhas,&nbsp;Rajeev Verma","doi":"10.1016/j.micron.2023.103563","DOIUrl":"10.1016/j.micron.2023.103563","url":null,"abstract":"<div><p>The present study aims at investigating the effect of interaction between the process parameters of each weld pass (1st pass and 2nd pass) to improve the joint performance during the double-sided friction stir welded joints of AA6061-T6 aluminium alloy<span><span>. Experimental designs were conducted following a design matrix developed using response surface methodology<span><span> to investigate the impact on the microstructural changes and tensile properties<span><span>. Pronounced interaction between the process parameters of each weld pass of the joint was observed and indicated a strong interdependency between them. The detailed microstructural study conducted through EBSD insights into the extent of </span>homogenization, and abnormal grain refinement and reflects a vast transformation of low-angle grain boundaries into high-angle grain boundaries within the stir zone. The profound examination through scanning electron microscopy and </span></span>transmission electron microscopy<span> analysis validated the uniform homogeneous distribution of Al-Fe and Al-Si-rich precipitates. The significant improvement in the grain refinement and distribution of the strengthening precipitates within the stir zone led to a substantial enhancement in the microhardness, along with achieving a maximum </span></span></span>ultimate tensile strength<span> of 223 MPa and a percentage elongation of 14%. A study of the fracture morphology ensures the ductile fracture behavior of the tensile fracture specimen by observing the presence of numerous dimples within a well-bonded joint.</span></span></p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135515265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sample thickness affects contrast and measured shape in TEM images and in electron tomograms","authors":"Misa Hayashida ,&nbsp;Jun Yamasaki ,&nbsp;Marek Malac","doi":"10.1016/j.micron.2023.103562","DOIUrl":"10.1016/j.micron.2023.103562","url":null,"abstract":"<div><p>We investigated the effect of nanoparticle<span> (NP) image broadening and its contrast change dependence on a support matrix thickness in a transmission electron microscope<span> (TEM). We measured the effect of NP size and atomic number on its image broadening. Based on the experimental TEM images we generated tomograms of NPs on four types of support matrix. The measured shape aspect ratio of the NPs in such tomograms depends on the geometry of the support matrix. For example, the aspect ratio of 6 nm NP placed on a thin film with window-frame support is 1.14, while the aspect ratio of 6 nm NP on a rod-shaped support with 910 nm diameter is 1.67 in a tomogram.</span></span></p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135510161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size-dependent and sex-specific negative effects of micro- and nano-sized polystyrene particles in the terrestrial invertebrate model Drosophila melanogaster","authors":"Anna Z. Urbisz,&nbsp;Karol Małota,&nbsp;Łukasz Chajec,&nbsp;Marta K. Sawadro","doi":"10.1016/j.micron.2023.103560","DOIUrl":"10.1016/j.micron.2023.103560","url":null,"abstract":"<div><p>Microplastic pollution is believed to be one of the most widespread and long-lasting changes on a global scale. Our understanding that microplastics significantly impact terrestrial systems and are a global change stressor continues to grow. In the present study, we investigated the negative effect of long-term (28 days of exposure in food) polystyrene particles of micro (1.0–1.9 µm, 0.4–0.6 µm) and nano (0.04–0.06 µm) scale, in low doses, on the fruit fly – representing a common, globally distributed terrestrial invertebrate, and a model species in many fields. Our observations involved such parameters as ingestion and transfer of particles, survival, reproduction, changes in ultrastructure and tissue and cell responses in midgut epithelium (the place of direct contact with plastic), ovary, and testis in adults, and transgenerational effects in larvae. These observations may indicate possible toxic effects of the tested substances, even in low doses, that can be expected in other taxa, in terrestrial ecosystems. We observed a negative impact of polystyrene particles on the fruit fly survival, midgut, ovary, and testis, involving ultrastructural alterations, such as autophagy and/or ultimately necrosis in the midgut, triggering oxidative stress and activating processes of antioxidative protection. Despite the changes, midgut function and reproduction were not altered – spermatogenesis and oogenesis proceeded normally. The effect was size-dependent – the smaller the polystyrene particles were, the more substantial was the impact they caused. Ultrastructural changes and studied parameters, i.e., generation of ROS (overproduction of which generates oxidative stress), total glutathione concentration (involved in defense against ROS, acting in distinct pathways), and total antioxidant concentration (the oxidative defense system) showed the highest levels after exposure to the smallest nanoparticles, and vice versa. The effect was also sex-dependent, with male flies being more sensitive. Negative effects in males were more substantial and more prominent, even after contact with larger particles, compared to females. The smaller particles (0.4–0.6 µm, 0.04–0.06 µm) were transferred to the ovary and accumulated in the oocytes. In this case, a transgenerational negative effect was detected in larvae. It was characterized by size-dependent alterations, with smaller particles triggering higher levels of ROS and cellular oxidative response. Only the largest particles (1.0–1.9 µm) did not pass into the gonad and did not alter the larvae. These observations together demonstrated that polystyrene particles of micro- and nanoscale, even in a low dose, can induce numerous negative effects on terrestrial invertebrates.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49691399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology and ultrastructure of the colleterial glands in Myzinum flower wasps (Tiphiidae, Hymenoptera)","authors":"Marjorie da Silva ,&nbsp;Cíntia Eleonora Lopes Justino ,&nbsp;Fernando Henrique Carnimeo ,&nbsp;Fernando Barbosa Noll ,&nbsp;Johan Billen","doi":"10.1016/j.micron.2023.103561","DOIUrl":"10.1016/j.micron.2023.103561","url":null,"abstract":"<div><p>The strategies used by females to ensure the survival of their offspring are one of the key elements in insect reproductive biology. Ectoparasitoid hymenopterans, such as tiphiid wasps, use their ovipositor to deliver a single egg on the host body, where the larva develops. Here we describe the colleterial glands in females of two species of <em>Myzinum</em> and discuss the homology with other glands among Hymenoptera. The glands appear as two large opaque round sac-like structures that are connected to the oviduct. Histological sections revealed a compound gland, with a single layer of class-1 epithelial cells surrounded by a layer of class-3 gland cells, which is uncommon in Hymenoptera. Ultrastructure points to active protein synthesis, consistent with the role of colleterial glands. Despite the consensus that colleterial glands in Hymenoptera evolved with two distinct forms, the venom gland and Dufour’s gland, the three glands were present in both <em>Myzinum</em> species. The few studies regarding the structure, function, and homology among the female accessory glands in Hymenoptera do not allow to make conclusive statements about the evolution of these glands. Therefore, the finding in <em>Myzinum</em> is probably the reflection of a lack of information, rather than an exception within Aculeata.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432823001592/pdfft?md5=011d9fa93a6beaaea21c54ebae0f235e&pid=1-s2.0-S0968432823001592-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71424890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellular evidence of communication strategies for small intestinal high endothelial cells: Ultrastructural insights of nano-scale exosomes and autophagy","authors":"Ping Hao ,&nbsp;Wen Yin ,&nbsp;Xi Chen ,&nbsp;Shuangshuang Qin ,&nbsp;Yue Yu ,&nbsp;Yuan Yuan ,&nbsp;Xiaoyu Quan ,&nbsp;Bing Hu ,&nbsp;Shouhai Chen ,&nbsp;Yi Wu","doi":"10.1016/j.micron.2023.103559","DOIUrl":"10.1016/j.micron.2023.103559","url":null,"abstract":"<div><p>Although several immune related cells of small intestine play an essential role in the intestinal homeostasis. However, information related to ultrastructural evidence of Nano-scale exosomes-multivesicular bodies and autophagic pathway in the high endothelial cells (HECs) of the small intestine in laying birds is still ambiguous. In present study, the HECs secreted the early endosome (ee), late endosome (le) and multivesicular bodies (MVBs) in the lamina propria of layer small intestine was confirmed by transmission electron microscopy. Besides that, in the cytoplasm of HECs showed many autophagosomes were directly associated with lysosomes and mitochondria. Further, the immunohistochemistry and immunofluorescence results showed that, the immunoreactivity and immuno-signaling of Nano-scale exosome related proteins, cluster of differentiation (CD63) and tumor susceptibility gene (TSG101), and autophagic related proteins, autophagic related gene (ATG7) and microtubule-associated protein light chain (LC3) were strong positive expression in the lamina propria of small intestine. These results prove that HECs play a well-known immunological role in the maintenance of intestinal homeostasis. In summary, these findings indicate that the small intestine’s HECs have developed an innovative way of communication.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0968432823001579/pdfft?md5=d428e4ab8b65051a3fd19338c8ae626b&pid=1-s2.0-S0968432823001579-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71483412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The gemological characteristics of yellow seawater bead-cultured pearl farming in Beihai City, southern China","authors":"Xuejun Yan ,&nbsp;Xiaobo Liu ,&nbsp;Wubang Zhou ,&nbsp;Dekun Zhou ,&nbsp;Peijun Liu ,&nbsp;Tao Chen ,&nbsp;Jun Yan","doi":"10.1016/j.micron.2023.103558","DOIUrl":"10.1016/j.micron.2023.103558","url":null,"abstract":"<div><p>In this study, we comparatively investigated the gemological and fine-microstructural characteristics of yellow seawater pearls cultured in <em>Pinctada fucata martensii</em> using X-ray computed microtomography (μ-CT) analysis, ultraviolet-visible (UV−Vis) reflectance spectroscopy, field emission scanning electron microscope (FE-SEM), Raman and photoluminescence (PL) spectroscopy, and Laser ablation−inductively coupled plasma−mass spectrometry (LA−ICP−MS). Detection of the nacre thickness indicated that the average nacre thickness varied from 0.17 to 1.35 mm, and further theoretical calculations showed that the nacre accounted for about 15–68% of the whole pearl by volume. For yellow or light-yellow pearls, the spectroscopy results showed characteristic patterns such as certain distinct absorption features around 360, 400, 430, and 450 nm in the UV−Vis reflection spectra and the organic pigment-related peaks at approximately 1130 and 1530 cm^–1 in the Raman spectra. Furthermore, dominant aragonite peak intensities were observed in the PL spectra of these samples, with the ratio between the overall fluorescence intensity (F) and the height of the main aragonite peak (A) consistently below 5. SEM observations showed that multiple amorphous structures, mainly composed of aragonite, coexisted in the nacre in these portions of the pearls, one of which was closely adjacent to the nucleus of the pearl. In addition, LA-ICP-MS analysis clearly revealed the nacre of the outer saltwater layers and the inner freshwater nucleus. Interestingly, we directly observed that the quantities of Na and Mg in the nacre were higher than that those in the freshwater nucleus. These findings substantially enhanced our knowledge of gemological, mineralogical, and fine-microstructural characteristics of as-grown yellow seawater pearls. Most importantly, this study revealed some key characteristics that could be used to identify imitation and color-treated yellow pearls and further guide the pearl production.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49691400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying colors at micrometer scale by colorimetric microscopy (C-Microscopy) approach","authors":"Benedykt R. Jany","doi":"10.1016/j.micron.2023.103557","DOIUrl":"10.1016/j.micron.2023.103557","url":null,"abstract":"<div><p>The color is the primal property of the objects around us and is direct manifestation of light-matter interactions. The color information is used in many different fields of science, technology and industry to investigate material properties or for identification of concentrations of substances. Usually the color information is used as a global parameter in a macro scale. To quantitatively measure color information in micro scale one needs to use dedicated microscope spectrophotometers or specialized micro-reflectance setups. Here, the Colorimetric Microscopy (C-Microscopy) approach based on digital optical microscopy and a free software is presented. The C-Microscopy approach uses color calibrated image and colorimetric calculations to obtain physically meaningful quantities i.e., dominant wavelength and excitation purity maps at micro level scale. This allows for the discovery of the local color details of samples surfaces. Later, to fully characterize the optical properties, the hyperspectral reflectance data at micro scale (reflectance as a function of wavelength for a each point) are colorimetrically recovered. The C-Microscopy approach was successfully applied to various types of samples i.e., two metamorphic rocks unakite and lapis lazuli, which are mixtures of different minerals; and to the surface of gold 99.999 % pellet, which exhibits different types of surface features. The C-Microscopy approach could be used to quantify the local optical properties changes of various materials at microscale in an accessible way. The approach is freely available as a set of python jupyter notebooks.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49679392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale pore network modelling to evaluate connectivity in ceramic composites","authors":"Joan Widin Schroeder,&nbsp;Matthew J. Burch,&nbsp;Mario A. Perez","doi":"10.1016/j.micron.2023.103556","DOIUrl":"10.1016/j.micron.2023.103556","url":null,"abstract":"<div><p>Complex morphologies, such as open or connected feature networks, are present in a wide variety of materials. Characteristics of these networks can impact key performance attributes of the materials themselves, affecting transport properties such as thermal conductivity. Therefore, it is critical to analyze the microstructure of these materials to gain a better understanding of the fundamental characteristics of the morphology. This study utilized pore network modeling as a method to extract morphological information on the solid network formed by boron nitride ceramic flakes in a polymeric resin matrix and uses the characteristics of the model to analyze the connectivity of the flakes. In this work, Micro-CT and FIB/SEM tomography were used in tandem to provide complimentary analyses of the microstructure and nanostructure, respectively, of the flake network to understand how this may contribute to transport properties of the material. Rather than a pore network model (PNM), the flake network model (FNM) was extracted from the tomographic datasets and the coordination number distribution was determined for the flakes detected in each. Micro-CT analysis showed that the flakes had formed a cage-like network around the exterior of the sample with limited connectivity in the interior, likely due to flake agglomeration at the outer surface of the material. A comparison of the full and interior-only Micro-CT FNMs indicated lower connectivity in the interior. This was confirmed by flow rate models generated from the network analysis for the flake contact points. The FNM extracted from the FIB/SEM tomography dataset exhibited similar connectivity compared to the interior-only FNM, indicating that the connectivity of the material was consistent when measured at the micron scale and at the nanometer scale.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49679391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of two methods for determination of crystal orientation using two Kikuchi pairs in electron diffraction patterns","authors":"Xing-Zhong Li","doi":"10.1016/j.micron.2023.103549","DOIUrl":"10.1016/j.micron.2023.103549","url":null,"abstract":"<div><p>Kikuchi diffraction pattern analysis is one of the essential techniques of transmission electron microscopy used in materials science. For instance, one important application is its use in crystal orientation determination. During the development of SAKI5 software for the simulation and analysis of Kikuchi patterns, two methods in the literature for crystal orientation determination from two independent Kikuchi pairs have been revisited and then implemented. This paper compares the formula derivations of these two methods, revealing their geometrical connections in terms of the optical path. The discussion is beneficial for electron microscopy researchers and students seeking insights into this research domain. A brief overview of a newly added module in SAKI5 software using these two methods is also provided, accompanied by a detailed example. Computational results indicate that better outcomes can be achieved by utilizing the average of both methods.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41204840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological and fractal features of cancer cells anchored on composite layers based on magnesium-doped hydroxyapatite loaded in chitosan matrix","authors":"Ştefan Ţălu ,&nbsp;Robert S. Matos ,&nbsp;Henrique Duarte da Fonseca Filho ,&nbsp;Daniela Predoi ,&nbsp;Simona Liliana Iconaru ,&nbsp;Carmen Steluţa Ciobanu ,&nbsp;Liliana Ghegoiu","doi":"10.1016/j.micron.2023.103548","DOIUrl":"10.1016/j.micron.2023.103548","url":null,"abstract":"<div><p>In the present study, we report the development and characterization of composite layers (by spin coating) based on magnesium-doped hydroxyapatite in a chitosan matrix, containing human osteosarcoma MG63 cells anchored. Studies regarding the biocompatibility of the composite layers were performed with the aid of a MTT (3–4,5-Dimethylthiazol 2,5-diphenyltetrazolium bromide) assay. The data determined that the composite layers did not inhibit the growth and adhesion of MG63 cells to their surfaces exhibiting good biocompatibility properties. Furthermore, the attachment and development of MG63 cells on the surface of MgHApCh composite layers were investigated using atomic force microscopy (AFM). AFM topographical maps emphasized that the HApCh and 8MgHApCh composite layers surface promoted the attachment and proliferation of MG63 cells on their surface. Meanwhile, in the case of 30MgHApCh layers incubated for 48 h, a slight modification of the morphological features of the MG63 cells. In addition, the effects of the composite layers against <em>Candida albicans</em> ATCC 10231 were also evaluated. The data results from the <em>in vitro</em> antifungal assay depicted that the composite layers successfully inhibited the growth of the fungal cells onto their surface. Morphological and fractal analyses unveil cancer cell surfaces on Mg-containing composite layers with intricate 3D patterns, driven by high-frequency components. Their remarkable complexity and roughness arises from a strong multifractal nature, supporting more effective vertical growth compared to Si and HApCh surfaces. The cell viability reduced of uncoated Si surface is highlighted by its less intense 3D pattern growth. Our results show that the uncoated Si surface promotes lower viability of MG63 cancer cells, with less rough and complex 3D spatial patterns.</p></div>","PeriodicalId":18501,"journal":{"name":"Micron","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41183054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}