Stomata (singular, “stoma”) are tiny pores through which plants breathe. Stomata are found on the upper and lower sides of leaves, on flower petals, on stems, and on roots. Scientists survey plant surfaces to determine the density and size of stomata and relate these findings to properties of the environment, such as temperature and the amounts of sunlight, humidity, oxygen, and carbon dioxide in the air when a leaf is formed. Stomata of various plants are suitable subjects for classroom laboratory activities since they may be examined by light microscopy.

Deep neural networks have attracted considerable attention because of their state-of-the-art performance on a variety of image restoration tasks, including image completion, denoising, and segmentation. However, their record of performance is built upon extremely large datasets. In many cases (for example, electron microscopy), it is extremely labor intensive, if not impossible, to acquire tens of thousands of images for a single project. The present work shows the possibility of attaining high-accuracy image segmentation, isolating regions of interest, for small datasets of transmission electron micrographs by employing encoder-decoder neural networks and image augmentation.

Exposure of the nuclear counterstain DAPI to just a few seconds of UV excitation light during fluorescence imaging can photoconvert the dye to stable green- and red-emitting forms, resulting in imaging artifacts in multi-color staining experiments. This article reviews the published literature on photoconversion and compares the effect of different mounting media on photoconversion of DAPI in stained tissue sections. Once photoconversion is recognized as a potential source of non-specific fluorescence, careful imaging practices or reagent selection can be used to avoid it.

Significant developments in micro-electrical-mechanical systems (MEMS)-based devices have led to the commercialization of windowed gas cells that now enable atomic-resolution scanning transmission electron microscopy (STEM) observation of phenomena occurring during gas-solid interactions at atmospheric pressure. An in situ atmospheric STEM study provides information that is beneficial to correlating the structure-properties relationship of catalytic nanomaterials, particularly under realistic gaseous reaction conditions. In this article, we illustrate the advantages of this tool as applied to our study of two important systems: (1) the CO-induced Pt nanoparticle surface reconstruction at saturation coverage and (2) the ordering and Pt surface enrichment in supported Pt3Co nanoparticles.

Electronic and ionic transport underpins functionality of broad range of electronic and energy devices, and is an active field of applied and fundamental research. The lecture series on Kelvin probe force microscopy and scanning probe microscopy (SPM) based current-voltage (I-V) transport measurements introduces the basic principles of SPM techniques for transport measurements based on potential and current detection, describes the multitude of dynamics variants of KPFM, KPFM-based transport measurements, and its implementation in ambient, vacuum, and liquid environments and associated artifacts. Multidimensional current- and capacitance-based transport measurements are described. The lectures are available at YouTube: https://www.youtube.com/playlist?list=PLS6ZvEWHZ3OOkRFPTrnsV3Ej09UGUjor3.

Cryo-planing SEM provides a powerful 3D view of internal and external tissue and cell features. However, specimen preparation is tedious because it requires custom apparatus and difficult cryogenic manipulations. We present an easy method using mPrep/s capsules that provide a “handle” to hold and orient specimens throughout cryo-preparation and imaging. Cryo-facing is done with a cryo-ultramicrotome, requiring no custom equipment while providing accurate control of the image plane. We show this with fresh Christmas cactus leaves and aldehyde-fixed kidney tissue imaged by room temperature SEM after freeze-drying, demonstrating the method operating without an expensive cryo-SEM.

Individual plant stomata were studied within a sealed environmental chamber that encloses a volume of space around a microscope objective. A leaf that is attached to a plant is secured to a temperature-controlled microscope stage, and the top surface of the leaf is illuminated via the microscope's light source while stomata on the underside of the leaf are observed through a microscope objective. Stomatal responses are observed on a leaf exposed to environmental conditions including various illuminations and changes in ambient CO2 level, at a given temperature.

Microbial-induced calcite precipitation (MICP) has gained much attention in soil improvement studies, where it can enhance the physical properties of sandy soil. Small-scale sand cylinder tests were conducted to investigate the formation and failure of calcium carbonate precipitation bonding between individual sand particles. Bonding formation by precipitation was examined by scanning electron microscopy. Energy-dispersive X-ray spectroscopy analysis verified the existence of calcium, carbon, and oxygen, which could form CaCO3 after MICP-treatment. Focused-ion-beam milling was applied to study the interior structure of calcium carbonate precipitation during the MICP process.

Positively charged (cationic) polymers are one of the most important types of polymers used in haircare products. Because of their high degree of substantivity to hair, they are useful in shampoos and conditioners. Numerous studies have shown that cationic conditioning compounds protect against hair damage caused by cosmetic chemical treatments and grooming practices. When hair care products are being developed, it is crucial that formulators determine the depositional characteristics of the polymer from a functional as well as a cost perspective. Microfluorometry can be used to quantitatively determine the amount of a polymer deposited on the surface of hair fibers and to determine the extent the polymer penetrates into the hair fibers. The data output is the fluorescent intensity obtained from scanning along a predefined length of hair fiber.

By combining a focused inert-gas ion beam instrument and a custom magnetic-sector mass spectrometer, high spatial resolution imaging and chemical analysis are provided within a single instrument. Sub-nanometer image resolution is achieved by secondary electron (SE) imaging, limited only by the probe-size of the primary beam, while the spatial resolution for chemical mapping obtained via secondary ion mass spectrometry (SIMS) is limited mainly by beam-sample interactions to about 10 nm. This article introduces the background behind this development, describes the instrument and its various operating modes, and presents examples of its applications.

This article describes an atomic force microscope (AFM) that can operate in any scanning electron microscope (SEM) or SEM combined with a focused ion-beam (FIB) column. The combination of AFM, SEM imaging, energy-dispersive X-ray spectrometry (EDX), FIB milling, and nanofabrication methods (field-emission scanning probe lithography, tip-based electron beam induced deposition, and nanomachining) provides a new tool for correlative nanofabrication and microscopy. Piezoresistive, thermo-mechanically actuated cantilevers (active cantilevers) are used for fast imaging and nanofabrication. Thus, the AFM with active cantilevers integrated into an SEM (AFMinSEM) can generate and characterize nanostructures in situ without breaking vacuum or contaminating the sample.

This article discusses the image processing challenges in modern microscopy and microanalysis associated with large dataset size, microstructure complexity, and growing computing requirements. Solutions for meeting these challenges include artificial intelligence and cloud computing, which provide improved efficiency in managing microscopy data, more robust automated image segmentation, and prediction of physical properties from images with user-friendly high-performance computing. The applications of these technologies in the industrial research environment are exemplified by studies in evaluation of amorphous drug formulations, tight rock characterization for sustainable hydrocarbon extraction, and low-temperature fuel cell design for an environment-friendly automobile.

LED illumination systems for fluorescence microscopy offer a wealth of benefits in comparison to traditional mercury and metal halide lamps, including ease of use, improved stability, and enhanced control. To fully realize these benefits, it is important to ensure that optical filters are configured correctly, which often can be confusing. However, without the correct filter configuration, experimental conditions can be suboptimal, and results may therefore be inaccurate. This article looks at optical filter setup in more depth, explaining the purpose and benefits of optimal LED filtering.

This overview is meant to help newer microscopists decide on an appropriate high-resolution method for nanoscale and microscale materials characterization. The operating principles, capabilities, and resolution of scanning electron microscopy (SEM) and atomic force microscopy (AFM), as well as the needs for sample preparation and the constraints imposed on the sample environment within the microscope, are compared and contrasted. This is followed by a similar assessment of the merits and challenges of transmission electron microscopy (TEM).

This article describes target material options for sputter coaters that deposit a thin metal coating on non-conductive SEM samples. Coating a sample with a conductive metal renders an insulating sample conductive enough to minimize charging effects on the SEM image. In most cases, coating SEM samples with only a few nanometers of a metal results in crisp, clear images. Proper target material selection is dictated by overall imaging requirements, the SEM available, the specimen material being evaluated, and whether X-ray microanalysis will be required.

In September 2018, Australia hosted the 19th International Microscopy Congress in Sydney. As part of this conference, more than 600 teachers and students from 19 classes across the state of NSW were hosted on-site at the IMC19 Outreach Learning Space. The program resulted from a year-long collaborative effort between Australian Microscopy and Microanalysis and Microscopy Australia volunteers, academics, microscopy industry vendors, conference coordinators, STEM secondary school teachers, and local attractions. A unique feature of the program was the incorporation of the Australian national curriculum into the program via teacher-designed prework and postwork, helping to contribute to an award-winning conference.

The objective lens is regarded as the critical component for an optimal image in light microscopy. Not every damage to the lens surface may be easily visible during maintenance when the objective is removed and observed. The internal lens organization produces a magnified image of the outer lens surface. Shining the light of a laser pointer into the lens, and reproducing the image of the light exiting onto a flat surface, produces different images for intact and damaged objective lenses.