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Chemical Reviews Jul 2023Catalysts are the primary facilitator in many dynamic processes. Therefore, a thorough understanding of these processes has vast implications for a myriad of energy... (Review)
Review
Catalysts are the primary facilitator in many dynamic processes. Therefore, a thorough understanding of these processes has vast implications for a myriad of energy systems. The scanning/transmission electron microscope (S/TEM) is a powerful tool not only for atomic-scale characterization but also catalytic experimentation. Techniques such as liquid and gas phase electron microscopy allow the observation of catalysts in an environment conducive to catalytic reactions. Correlated algorithms can greatly improve microscopy data processing and expand multidimensional data handling. Furthermore, new techniques including 4D-STEM, atomic electron tomography, cryogenic electron microscopy, and monochromated electron energy loss spectroscopy (EELS) push the boundaries of our comprehension of catalyst behavior. In this review, we discuss the existing and emergent techniques for observing catalysts using S/TEM. Challenges and opportunities highlighted aim to inspire and accelerate the use of electron microscopy to further investigate the complex interplay of catalytic systems.
PubMed: 37327473
DOI: 10.1021/acs.chemrev.2c00880 -
Indian Journal of Thoracic and... Dec 2023The traditional view of the aortic valve and aortic root as a simple conduit for blood flow between the left ventricle and the aorta is evolving with new insights from... (Review)
Review
The traditional view of the aortic valve and aortic root as a simple conduit for blood flow between the left ventricle and the aorta is evolving with new insights from anatomy, physiology, cell biology, and advanced imaging techniques. This article provides an overview of the changing understanding of aortic root anatomy, shedding light on the intricate structures that contribute to maintaining unidirectional blood flow and the durability of the aortic valve. From historical perspectives to contemporary microscopic details, the components of the aortic root are explored, including the sinutubular junction, aortic sinuses, valve leaflets, and interleaflet triangles. Microscopically, the aortic annulus and leaflets reveal a complex architecture that facilitates blood flow while withstanding lifetime stresses. Additionally, the clinical relevance of aortic anatomy in surgical interventions is emphasized, highlighting the importance of preserving natural anatomy and physiology. A thorough understanding of the aortic root's complexity is crucial for optimizing therapeutic approaches and improving patient outcomes, paving the way for future advancements in aortic valve repair and regeneration techniques.
PubMed: 38093909
DOI: 10.1007/s12055-023-01645-x -
Scientific Reports Jul 2023In the last decade, Ultrafast ultrasound localisation microscopy has taken non-invasive deep vascular imaging down to the microscopic level. By imaging diluted...
In the last decade, Ultrafast ultrasound localisation microscopy has taken non-invasive deep vascular imaging down to the microscopic level. By imaging diluted suspensions of circulating microbubbles in the blood stream at kHz frame rate and localizing the center of their individual point spread function with a sub-resolution precision, it enabled to break the unvanquished trade-off between depth of imaging and resolution by microscopically mapping the microbubbles flux and velocities deep into tissue. However, ULM also suffers limitations. Many small vessels are not visible in the ULM images due to the noise level in areas dimly explored by the microbubbles. Moreover, as the vast majority of studies are performed using 2D imaging, quantification is limited to in-plane velocity or flux measurements which hinders the accurate velocity determination and quantification. Here we show that the backscattering amplitude of each individual microbubble can also be exploited to produce backscattering images of the vascularization with a higher sensitivity compared to conventional ULM images. By providing valuable information about the relative distance of the microbubble to the 2D imaging plane in the out-of-plane direction, backscattering ULM images introduces a physically relevant 3D rendering perception in the vascular maps. It also retrieves the missing information about the out-of-plane motion of microbubbles and provides a way to improve 3D flow and velocity quantification using 2D ULM. These results pave the way to improved visualization and quantification for 2D and 3D ULM.
Topics: Microscopy; Microbubbles; Phantoms, Imaging; Biological Phenomena; Ultrasonography; Contrast Media
PubMed: 37455266
DOI: 10.1038/s41598-023-38531-w -
Microscopy Research and Technique Jul 2024The outbreak of COVID-19 exposed the inadequacy of our technical tools for home health surveillance, and recent studies have shown the potential of smartphones as a...
The outbreak of COVID-19 exposed the inadequacy of our technical tools for home health surveillance, and recent studies have shown the potential of smartphones as a universal optical microscopic imaging platform for such applications. However, most of them use laboratory-grade optomechanical components and transmitted illuminations to ensure focus tuning capability and imaging quality, which keeps the cost of the equipment high. Here, we propose an ultra-low-cost solution for smartphone microscopy. To realize focus tunability, we designed a seesaw-like structure capable of converting large displacements on one side into small displacements on the other (reduced to ∼9.1%), which leverages the intrinsic flexibility of 3D printing materials. We achieved a focus-tuning accuracy of ∼5 𝜇m, which is 40 times higher than the machining accuracy of the 3D-printed lens holder itself. For microscopic imaging, we used an off-the-shelf smartphone camera lens as the objective and the built-in flashlight as the illumination. To compensate for the resulting image quality degradation, we developed a learning-based image enhancement method. We used the CycleGAN architecture to establish the mapping from smartphone microscope images to benchtop microscope images without pairing. We verified the imaging performance on different biomedical samples. Except for the smartphone, we kept the full costs of the device under 4 USD. We think these efforts to lower the costs of smartphone microscopes will benefit their applications in various scenarios, such as point-of-care testing, on-site diagnosis, and home health surveillance. RESEARCH HIGHLIGHTS: We propose a solution for ultra-low-cost smartphone microscopy. Utilizing the flexibility of 3D-printed material, we can achieve focusing accuracy of ∼5 𝜇m. Such a low-cost device will benefit point-of-care diagnosis and home health surveillance.
Topics: Smartphone; Microscopy; Humans; COVID-19; SARS-CoV-2; Printing, Three-Dimensional; Image Processing, Computer-Assisted
PubMed: 38419399
DOI: 10.1002/jemt.24535 -
Computer Methods and Programs in... Oct 2023Due to the depth of focus (DOF) limitations of the optical systems of microscopes, it is often difficult to achieve full clarity from microscopic biomedical images under...
BACKGROUND AND OBJECTIVE
Due to the depth of focus (DOF) limitations of the optical systems of microscopes, it is often difficult to achieve full clarity from microscopic biomedical images under high-magnification microscopy. Multifocus microscopic biomedical image fusion (MFBIF) can effectively solve this problem. Considering both information richness and visual authenticity, this paper proposes a transformer network for MFBIF called TransFusion-Net.
METHODS
TransFusion-Net consists of two modules. One module is an interlayer cross-attention module, which is used to obtain feature mappings under the long-range dependencies observed among multiple nonfocus source images. The other module is a spatial attention upsampling network (SAU-Net) module, which is used to obtain global semantic information after further spatial attention is applied. Thus, TransFusion-Net can simultaneously receive multiple input images from a nonfull-focus microscope and make full use of the strong correlations between the source images to output accurate fusion results in an end-to-end manner.
RESULTS
The fusion results were quantitatively and qualitatively compared with those of eight state-of-the-art algorithms. In the quantitative experiments, five evaluation metrics, Q, Q, Q, Q, and PSNR, were used to evaluate the performance of each method, and the proposed method achieved values of 0.6574, 8.4572, 5.6305, 0.7341, and 89.5685, respectively, which are higher than those of the current state-of-the-art algorithms. In the qualitative experiments, a differential image was used for further validation, and the near-zero residuals visually verified the adequacy of the proposed method for fusion. Furthermore, we showed some fusion results of multifocused biomedical microscopy images to verify the reliability of the proposed method, which shows high-quality fusion results.
CONCLUSION
Multifocus biomedical microscopic image fusion can be accurately and effectively achieved by devising a deep convolutional neural network with joint cross-attention and spatial attention mechanisms.
Topics: Reproducibility of Results; Algorithms; Benchmarking; Electric Power Supplies; Microscopy; Image Processing, Computer-Assisted
PubMed: 37487310
DOI: 10.1016/j.cmpb.2023.107688 -
Neurosurgical Focus: Video Jan 2024The occipital approach for pineal tumors was first described by James Poppen in 1966. Since then, it has been widely used for accessing deep-seated tumors as it offers a...
The occipital approach for pineal tumors was first described by James Poppen in 1966. Since then, it has been widely used for accessing deep-seated tumors as it offers a wider surgical view than the supracerebellar transtentorial approach. This video demonstrates the technical nuances of the occipital transtentorial approach and the exoscopic dissection of a pineal gland tumor in a 66-year-old male. Use of the exoscope over the microscope provides certain ergonomic advantages and improves surgical workflow, as demonstrated here. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23161.
PubMed: 38283813
DOI: 10.3171/2023.10.FOCVID23161 -
IScience Oct 2023In the imaging process of conventional optical microscopy, the primary factor hindering microscope resolution is the energy diffusion of incident light, most directly... (Review)
Review
In the imaging process of conventional optical microscopy, the primary factor hindering microscope resolution is the energy diffusion of incident light, most directly described by the point spread function (PSF). Therefore, accurate calculation and measurement of PSF are essential for evaluating and enhancing imaging resolution. Currently, there are various methods to obtain PSFs, each with different advantages and disadvantages suitable for different scenarios. To provide a comprehensive analysis of PSF-obtaining methods, this study classifies them into four categories based on different acquisition principles and analyzes their advantages and disadvantages, starting from the propagation property of light in optical physics. Finally, two PSF-obtaining methods are proposed based on mathematical modeling and deep learning, demonstrating their effectiveness through experimental results. This study compares and analyzes these results, highlighting the practical applications of image deblurring.
PubMed: 37822495
DOI: 10.1016/j.isci.2023.107976 -
Sensors (Basel, Switzerland) Jul 2023Bioretention cells, or rain gardens, can effectively reduce many contaminants in polluted stormwater through phytoremediation and bioremediation. The vegetated soil... (Review)
Review
Bioretention cells, or rain gardens, can effectively reduce many contaminants in polluted stormwater through phytoremediation and bioremediation. The vegetated soil structure develops bacterial communities both within the soil and around the vegetation roots that play a significant role in the bioremediative process. Prediction of a bioretention cell's performance and efficacy is essential to the design process, operation, and maintenance throughout the design life of the cell. One of the key hurdles to these important issues and, therefore, to appropriate designs, is the lack of effective and inexpensive devices for monitoring and quantitatively assessing this bioremediative process in the field. This research reviews the available technologies for biomass monitoring and assesses their potential for quantifying bioremediative processes in rain gardens. The methods are discussed based on accuracy and calibration requirements, potential for use in situ, in real-time, and for characterizing biofilm formation in media that undergoes large fluctuations in nutrient supply. The methods discussed are microscopical, piezoelectric, fiber-optic, thermometric, and electrochemical. Microscopical methods are precluded from field use but would be essential to the calibration and verification of any field-based sensor. Piezoelectric, fiber-optic, thermometric, and some of the electrochemical-based methods reviewed come with limitations by way of support mechanisms or insufficient detection limits. The impedance-based electrochemical method shows the most promise for applications in rain gardens, and it is supported by microscopical methods for calibration and validation.
Topics: Biomass; Rain; Gardening; Soil; Nutrients
PubMed: 37514698
DOI: 10.3390/s23146404 -
Journal of Cataract and Refractive... Sep 2023The recent development of high-resolution, heads-up, 3D visualization microscopy systems has provided new technical and visualization options for ophthalmic surgeons. In... (Review)
Review
The recent development of high-resolution, heads-up, 3D visualization microscopy systems has provided new technical and visualization options for ophthalmic surgeons. In this review, we explore the evolution of microscope technologies, the science behind modern 3D visualization microscopy systems, and the practical benefits (as well as disadvantages) that these systems provide over conventional microscopes for intraocular surgical practice. Overall, modern 3D visualization systems reduce the requirements for artificial illumination and provide enhanced visualization and resolution of ocular structures, improving ergonomics, and facilitating a superior educational experience. Even when considering their disadvantages, such as those related to technical feasibility, 3D visualization systems have an overall positive benefit/risk ratio. It is hoped these systems will be adopted into routine clinical practice, pending further clinical evidence on the benefits they may provide on clinical outcomes.
Topics: Humans; Microscopy; Imaging, Three-Dimensional; Eye; Surgery, Computer-Assisted
PubMed: 37144641
DOI: 10.1097/j.jcrs.0000000000001216 -
FEBS Letters Oct 2023A journey from the earliest known use of lenses and magnifying glasses in ancient times, through the development of microscopes and towards modern electron microscopy... (Review)
Review
A journey from the earliest known use of lenses and magnifying glasses in ancient times, through the development of microscopes and towards modern electron microscopy techniques. The evolving technology and improved microscopes enabled the discovery of intracellular organelles, the nucleus and nuclear pore complexes (NPCs). Current advances have led to composite three-dimensional models showing NPC structure in unprecedented detail but relying on the averaging of many images. A complementary approach is field emission scanning electron microscopy providing topographic surface images that are easily and intuitively interpreted by our brain. Recent advances in this technique have made it possible to expose nuclei from human cells and to focus on individual NPCs and their architectural features.
PubMed: 37777820
DOI: 10.1002/1873-3468.14746