Hasil untuk "Microscopy"

S. Hell

C. Wongsrichanalai, M. Barcus, Sinuon Muth et al.

Mollenhauer Hh

A. Huxley, R. Niedergerke

J. Sharpe, U. Ahlgren, Paul Perry et al.

K. Svoboda, R. Yasuda

R. Yuste

G. Meyer, N. Amer

M. Adrian, J. Dubochet, J. Lepault et al.

X. Shu, V. Lev-Ram, T. Deerinck et al.

Electron microscopy (EM) achieves the highest spatial resolution in protein localization, but specific protein EM labeling has lacked generally applicable genetically encoded tags for in situ visualization in cells and tissues. Here we introduce “miniSOG” (for mini Singlet Oxygen Generator), a fluorescent flavoprotein engineered from Arabidopsis phototropin 2. MiniSOG contains 106 amino acids, less than half the size of Green Fluorescent Protein. Illumination of miniSOG generates sufficient singlet oxygen to locally catalyze the polymerization of diaminobenzidine into an osmiophilic reaction product resolvable by EM. MiniSOG fusions to many well-characterized proteins localize correctly in mammalian cells, intact nematodes, and rodents, enabling correlated fluorescence and EM from large volumes of tissue after strong aldehyde fixation, without the need for exogenous ligands, probes, or destructive permeabilizing detergents. MiniSOG permits high quality ultrastructural preservation and 3-dimensional protein localization via electron tomography or serial section block face scanning electron microscopy. EM shows that miniSOG-tagged SynCAM1 is presynaptic in cultured cortical neurons, whereas miniSOG-tagged SynCAM2 is postsynaptic in culture and in intact mice. Thus SynCAM1 and SynCAM2 could be heterophilic partners. MiniSOG may do for EM what Green Fluorescent Protein did for fluorescence microscopy.

K. Sandau

J. Frank

Xiaoyi Zhu, Maomao Chen, Junjie Yao

Photoacoustic microscopy (PAM) is a hybrid in vivo imaging technique that acoustically detects optical contrast via the photoacoustic effect. Unlike pure optical microscopic techniques, PAM takes advantage of the weak acoustic scattering in tissue and thus breaks through the optical diffusion limit (∼1 mm in soft tissue). With its excellent scalability, PAM can provide high‐resolution images at desired maximum imaging depths up to a few millimeters. Compared with backscattering‐based confocal microscopy and optical coherence tomography, PAM provides absorption contrast instead of scattering contrast. Furthermore, PAM can image more molecules, endogenous or exogenous, at their absorbing wavelengths than fluorescence‐based methods, such as wide‐field, confocal, and multi‐photon microscopy. Most importantly, PAM can simultaneously image anatomical, functional, molecular, flow dynamic and metabolic contrasts in vivo. Focusing on state‐of‐the‐art developments in PAM, this Review discusses the key features of PAM implementations and their applications in biomedical studies.

S. Park, A. Zewail

Nardeep Kumar, S. Najmaei, Q. Cui et al.

We show that the lack of inversion symmetry in monolayer MoS2 allows strong optical second harmonic generation. Second harmonic of an 810-nm pulse is generated in a mechanically exfoliated monolayer, with a nonlinear susceptibility on the order of 1E-7 m/V. The susceptibility reduces by a factor of seven in trilayers, and by about two orders of magnitude in even layers. A proof-of-principle second harmonic microscopy measurement is performed on samples grown by chemical vapor deposition, which illustrates potential applications of this effect in fast and non-invasive detection of crystalline orientation, thickness uniformity, layer stacking, and single-crystal domain size of atomically thin films of MoS2 and similar materials.

Utku Böcüoğlu, Esra Ateş Yıldırım, Selma Erdoğan Düzcü et al.

Abstract Objectives This in vitro study aimed to evaluate the effect of laser photobiomodulation on the structural integrity and degradation resistance of two types of platelet-rich fibrin membranes: Leukocyte- and Platelet-Rich Fibrin (L-PRF) and Titanium-Prepared Platelet-Rich Fibrin (T-PRF). Structural changes in the fibrin network were assessed using Scanning Electron Microscopy (SEM) and light microscopy. Materials and methods Our study was performed on 15 systemically healthy individuals and four L-PRF and four T-PRF membranes obtained from each individual, totaling 120 samples. L-PRF was prepared first using standard vacuum glass tubes. Two weeks later, new blood samples were collected from the same individuals, and T-PRF membranes were prepared using sterile titanium tubes to enhance biocompatibility. Both membrane types were obtained by centrifugation at 2700 revolutions per minute (rpm) for 12 min. Two of the four membranes were treated with a diode laser device at a wavelength of 980 nanometers (nm) and a power of 0.5 W (W) in continuous mode for 3 min at a distance of 1–2 milimeters (mm). The other two membranes were not lasered. One of the laser treated L-PRF and T-PRF membranes was cut in half and stored under appropriate conditions for histological examination and SEM analysis. The other membrane was separated for degradation. The same procedures were performed for L-PRF and T-PRF membranes without laser treatment. Result Laser-treated L-PRF and T-PRF membranes showed lower degradation percentages compared to non-laser-treated membranes, but this difference did not reach statistical significance (p > 0.05). However, when laser treated L-PRF and T-PRF membranes were compared, the degradation percentage was significantly higher in L-PRF membrane (p < 0.05). Histologic examination showed that the fibrin network structure of the laser-applied L-PRF and T-PRF membrane groups was significantly denser than the non-laser-applied groups (p < 0.05). SEM analysis revealed that the fibrin network was denser, thicker and more complex in the laser-applied L-PRF and T-PRF membrane groups. Conclusion In this study, the biostimulative effect of laser increased the fibrin network thickness, cross-link structure and density of L-PRF and T-PRF membranes. When the degradation percentages on the membranes were evaluated, no significant difference was observed between the groups. Clinical relevance Understanding how laser photobiomodulation affects the structure and degradation resistance of both L-PRF and T-PRF membranes can guide clinicians in selecting the most suitable autologous biomaterial for enhancing wound healing and regenerative outcomes in dental procedures. The structure of PRF membranes used in dentistry can be improved using the biostimulative effect of the laser. This application may increase the use of these autologous and easily obtainable materials in treatments.

Hannah F. Nicholson, Christopher Zdyrski, Christina M. Leyson et al.

Abstract High pathogenicity avian influenza viruses pose a growing threat to poultry, livestock, wildlife, and humans as they undergo accelerated expansion of host and geographical ranges. Since 2020, these viruses have driven a panzootic characterized by extensive viral diversification and spillover into species previously considered to be resistant. There is currently a lack of physiologically relevant in vitro models that can be used to screen the rapidly changing viral landscape. To address this need, we describe the first chicken lung organoids derived from adult stem cells of specific pathogen free White Leghorns. We analyze their gene expression with bulk RNA sequencing, confirm their cellular heterogeneity via single-nuclei RNA sequencing, and provide basic morphological characterization using hematoxylin and eosin staining, immunohistochemistry, and transmission electron microscopy. The results indicate that the organoids contained several cell types, including non-ciliated columnar, cuboidal, squamous, and mucin-producing cells, representative of different regions of the avian respiratory system. Furthermore, expression of genes relevant to influenza A virus infection and replication appeared to be conserved across organoid and tissue samples. Infections revealed that chicken lung organoids support robust replication of both low and high pathogenicity avian influenza A viruses, with high pathogenicity strains showing more rapid amplification. Therefore, these organoids have the potential to effectively model viral infection, enabling the investigation of viral pathogenesis and evolutionary potential, virus-host interactions, and antiviral targets.

X. Ou, G. Zheng, Changhuei Yang

We develop and test a pupil function determination algorithm, termed embedded pupil function recovery (EPRY), which can be incorporated into the Fourier ptychographic microscopy (FPM) algorithm and recover both the Fourier spectrum of sample and the pupil function of imaging system simultaneously. This EPRY-FPM algorithm eliminates the requirement of the previous FPM algorithm for a priori knowledge of the aberration in the imaging system to reconstruct a high quality image. We experimentally demonstrate the effectiveness of this algorithm by reconstructing high resolution, large field-of-view images of biological samples. We also illustrate that the pupil function we retrieve can be used to study the spatially varying aberration of a large field-of-view imaging system. We believe that this algorithm adds more flexibility to FPM and can be a powerful tool for the characterization of an imaging system's aberration.

Rishi Ram, Bhawna, Sanjeev Kumar et al.

IntroductionPesticides such as isoproturon are widely employed and represent a considerable environmental concern. The development of sustainable and efficient degrading techniques is crucial. Photocatalytic degradation employing semiconductor materials is a compelling solution. This study examines the synergistic advantages of heterojunction formation by synthesizing, characterizing, and improving the photocatalytic efficacy of Ag3PO4/SnO2 nanocomposites for the degradation of isoproturon.MethodsThe Ag3PO4/SnO2 nanocomposite was characterised using powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Ultraviolet-Diffuse Reflectance Spectroscopy (UV-DRS) and X-ray Photoelectron Spectroscopy (XPS). The effective synthesis of the Ag3PO4/SnO2 heterojunction was confirmed by characterization data from various techniques (PXRD, FTIR, SEM, UV-DRS, XPS).Results and DiscussionElemental mapping confirmed uniform distribution of O, P, Ag, and Sn. High-resolution mass spectrometry (HRMS) was employed to analyse degradation products. The Ag3PO4/SnO2 nanocomposite exhibited improved photocatalytic degradation of isoproturon compared to its precursors. In contrast to 25% for pure SnO2 and 41% for Ag3PO4, over 97% degradation was achieved using Ag3PO4/SnO2 nanocomposite within 120 min of light irradiation under identical conditions. The synergistic effects of heterojunction formation significantly enhanced isoproturon degradation using the Ag3PO4/SnO2 nanocomposite. The heterojunction reduces electron-hole recombination rate and enhances photogenerated charge carriers for degradation via effective charge separation. The improved photocatalytic activity is ascribed to the increased surface area of the nanocomposite. The analysis of HRMS data revealed the degradation products. The findings demonstrate the efficacy of Ag3PO4/SnO2 nanocomposites as photocatalysts for environmental remediation, namely in the breakdown of pesticides.

Zeynep Akkutay-Yoldar, Mehmet Türkay Yoldar, Yiğit Burak Akkaş et al.

Abstract Identifying viral replication within cells demands labor-intensive isolation methods, requiring specialized personnel and additional confirmatory tests. To facilitate this process, we developed an AI-powered automated system called AI Recognition of Viral CPE (AIRVIC), specifically designed to detect and classify label-free cytopathic effects (CPEs) induced by SARS-CoV-2, BAdV-1, BPIV3, BoAHV-1, and two strains of BoGHV-4 in Vero and MDBK cell lines. AIRVIC utilizes convolutional neural networks, with ResNet50 as the primary architecture, trained on 40,369 microscopy images at various magnifications. AIRVIC demonstrated strong CPE detection, achieving 100% accuracy for the BoGHV-4 DN-599 strain in MDBK cells, the highest among tested strains. In contrast, the BoGHV-4 MOVAR 33/63 strain in Vero cells showed a lower accuracy of 87.99%, the lowest among all models tested. For virus classification, a multi-class accuracy of 87.61% was achieved for bovine viruses in MDBK cells; however, it dropped to 63.44% when the virus was identified without specifying the cell line. To the best of our knowledge, this is the first research article published in English to utilize AI for distinguishing animal virus infections in cell culture. AIRVIC’s hierarchical structure highlights its adaptability to virological diagnostics, providing unbiased infectivity scoring and facilitating viral isolation and antiviral efficacy testing. Additionally, AIRVIC is accessible as a web-based platform, allowing global researchers to leverage its capabilities in viral diagnostics and beyond.