Springer Science and Business Media LLC

Melanin has been a widely researched pigment by scientists for decades as it is undoubtedly the most ubiquitous and ancient pigment found in nature. Melanin plays very significant roles in structural plumage colors in birds: it has visible light-absorbing capabilities, and nanoscale structures can be formed by self-assembling melanin granules. Herein, we review recent progress on melanin-based structural coloration research. We hope that this review will provide current understanding of melanin’s structural and optical properties, natural coloration mechanisms, and biomimetic methods to implement artificial melanin-based structural colors.

Histopathology is a well-established standard diagnosis employed for the majority of malignancies, including breast cancer. Nevertheless, despite training and standardization, it is considered operator-dependent and errors are still a concern. Fractal dimension analysis is a computational image processing technique that allows assessing the degree of complexity in patterns. We aimed here at providing a robust and easily attainable method for introducing computer-assisted techniques to histopathology laboratories. Slides from two databases were used: A) Breast Cancer Histopathological; and B) Grand Challenge on Breast Cancer Histology. Set A contained 2480 images from 24 patients with benign alterations, and 5429 images from 58 patients with breast cancer. Set B comprised 100 images of each type: normal tissue, benign alterations, in situ carcinoma, and invasive carcinoma. All images were analyzed with the FracLac algorithm in the ImageJ computational environment to yield the box count fractal dimension (Db) results. Images on set A on 40x magnification were statistically different (p = 0.0003), whereas images on 400x did not present differences in their means. On set B, the mean Db values presented promissing statistical differences when comparing. Normal and/or benign images to in situ and/or invasive carcinoma (all p < 0.0001). Interestingly, there was no difference when comparing normal tissue to benign alterations. These data corroborate with previous work in which fractal analysis allowed differentiating malignancies. Computer-aided diagnosis algorithms may beneficiate from using Db data; specific Db cut-off values may yield ~ 99% specificity in diagnosing breast cancer. Furthermore, the fact that it allows assessing tissue complexity, this tool may be used to understand the progression of the histological alterations in cancer.

Two thickness measurement methods using an electron energy loss spectroscopy (EELS) and 10a convergent beam electron diffraction (CBED) were compared in an Fe-18Mn-0.7C alloy. The thin foil specimen was firstly tilted to satisfy 10a two-beam condition. Low loss spectra of EELS and CBED patterns were acquired in scanning transmission electron microscopy (STEM) and TEM-CBED modes under the two-beam condition. The log-ratio method was used for measuring the thin foil thickness. Kossel-Möllenstedt (K-M) fringe of the $$ \mathbf{13}\overline{\mathbf{1}} $$131¯ diffracted disk of austenite was analyzed to evaluate the thickness. The results prove the good coherency between both methods in the thickness range of 72 ~ 113 nm with a difference of less than 5%.

Kính hiển vi quét điện tử (SEM) đóng vai trò trung tâm trong việc phân tích cấu trúc bằng cách chụp hình một diện tích lớn của mô não ở quy mô nanomet. Một lượng lớn dữ liệu trong diện tích lớn là cần thiết để nghiên cứu các thay đổi cấu trúc của các bào quan tế bào trong một tế bào cụ thể, chẳng hạn như nơron, astrocyte, oligodendrocyte và microglia trong mô não, với độ phân giải đủ. Hình ảnh mảng là một phương pháp hữu ích cho hình ảnh diện tích lớn, và các phương pháp osmi-thiocarbohydrazide-osmi (OTO) và osmi giảm ferrocyanide thường được sử dụng để tăng cường độ tương phản màng.

Do nhiều mẫu được chuẩn bị bằng kỹ thuật thông thường mà không có nhuộm en bloc được coi là không đủ cho hình ảnh mảng, chúng tôi đã đề xuất một kỹ thuật thay thế sử dụng mẫu nhuộm sau và so sánh những lợi thế của nó.

Zoonotic poxvirus infections pose significant threat to human health as we have witnessed recent spread of monkeypox. Therefore, insights into molecular mechanism behind poxvirus replication cycle are needed for the development of efficient antiviral strategies. Virion assembly is one of the key steps that determine the fate of replicating poxviruses. However, in-depth understanding of poxvirus assembly is challenging due to the complex nature of multi-step morphogenesis and heterogeneous virion structures. Despite these challenges, decades of research have revealed virion morphologies at various maturation stages, critical protein components and interactions with host cell compartments. Transmission electron microscopy has been employed as an indispensable tool for the examination of virion morphology, and more recently for the structure determination of protein complexes. In this review, we describe some of the major findings in poxvirus morphogenesis and the contributions of continuously advancing electron microscopy techniques.

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of dwarf rainbowfish (Melanotaenia praecox) belong to Melanotaeniidae using light and electron microscopes. The fertilized eggs were spherical with adhesive filament, transparent, demersal, and had a narrow perivitelline space and small oil droplets. The size of fertilized egg was 1.02 ± 0.18 mm (n = 30), and there were two kinds of adhesive filament on the fertilized eggs. The long and thick (diameter 12.22 ± 0.52 μm, n = 20) adhesive filaments were only at the area of animal pole, and short and thin (diameter 1.99 ± 0.23 μm, n = 20) adhesive filaments were around the long filaments. A micropyle was conical shaped with adhesive filament and located near the animal pole of egg. The outer surface of fertilized egg was rough side. Also, the total thickness of the fertilized egg envelope was about 7.46 ± 0.41 μm (n = 20), the fertilized egg envelope consisted of two layers, an inner lamellae layer and an outer layer with high electron-density. And the inner layer was 8 layers. Collectively, these morphological characteristics and adhesive property of fertilized egg with adhesive filaments, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

We demonstrate a fabrication of an atomically controlled single-crystal heart-shaped nanostructure using a convergent electron beam in a scanning transmission electron microscope. The delicately controlled e-beam enable epitaxial crystallization of perovskite oxide LaAlO₃ grown out of the relative conductive interface (i.e. 2 dimensional electron gas) between amorphous LaAlO₃/crystalline SrTiO₃.

Việc chuẩn bị mẫu là rất quan trọng để xác định vật liệu nano bằng kính hiển vi điện tử truyền qua độ phân giải cao (HRTEM). Tuy nhiên, nhiều dung môi hữu cơ thông thường có thể hòa tan lớp hỗ trợ polymer hữu cơ cần thiết trong lưới TEM, điều này làm cho việc thu được mẫu chất lượng cao của các vật liệu nano tan trong dầu trở nên khó khăn. Trong nghiên cứu này, một phương pháp chuẩn bị mẫu mới cho các vật liệu nano tan trong dầu đã được phát triển bằng cách sử dụng vật liệu thăng hoa làm lớp chuyển tiếp. Các thí nghiệm cũng cho thấy không có thiệt hại nào xảy ra đối với lưới TEM và hình ảnh HRTEM chất lượng cao có thể được thu nhận thông qua phương pháp này. Cách tiếp cận này mở đường cho việc chuẩn bị mẫu HRTEM áp dụng cho các vật liệu nano tan trong dầu.

The detailed anatomy, ultrastructure and histology of the olfactory organ ofMicropterus salmoideswere investigated by a stereo microscope, a light microscope, and a scanning electron microscope. Its external structure shows a tube-like anterior nostril to stick out and a posterior nostril flat to the skin surface. Meanwhile, its internal structure, the olfactory chamber, contains a fan-shaped rosette structure with 9 to 11 lamellae in adult fish over 35 cm in standard length (SL) and two accessory nasal sacs (ethmoidal and lacrimal sacs) were found. Interestingly, the rosette in young fish under 15 cm in SL was a longitudinal structure in parallel with each of 4–5 lamellae. Histologically, the sensory epithelium (SE) on the olfactory chamber consists of 5 types of cells: olfactory receptor neurons, supporting cells, basal cells, lymphatic cells and mucous cells. In contrast, the non-sensory epithelium (NSE) has stratified epithelial cells, lymphatic cells and mucous cells. The mucous cells of the SE are abundant and distributed densely in one row on the outermost superficial surface, but the one of the NSE are less than the SE. From these results, the olfactory characters ofM. salmoidesmay be related with its ecological habit spending in the middle layer of stagnant water contaminated, more or less.