Microscope Objective Research Articles

ИЗМЕНЕНИЕ ВИДОВОГО СОСТАВА, БИОЭКОЛОГИИ И ВРЕДОНОСНОСТИ ОСНОВНЫХ ФИТОФАГОВ ЯБЛОНИ В ЦЕНТРАЛЬНОМ РАЙОНЕ НЕЧЕРНОЗЕМНОЙ ЗОНЫ РОССИИ ПОД ВЛИЯНИЕМ КЛИМАТИЧЕСКИХ ФАКТОРОВ

The studies were carried out at the Federal State Budgetary Scientific Organization “Federal Horticultural Center for Breeding, Agrotechnology and Nursery” (FSBSI FRCHBAN) in 1995-2020. The aim of the research was to clarify the species composition, bioecology, and the characteristics of harmfulness of the main phytophages of apple trees in the Central Region of the Non-Black Earth Zone of Russia under climate change conditions. Route surveys were carried out in 5 regions of this zone - Bryansk, Kaluga, Moscow, Ryazan, Tula. When studying the bioecological features of the development and dynamics of summer of the codling moth and corrosive arboretum, along with other methods, pheromone traps were used. Trapping belts (sticky and corrugated paper) were used to signal the exit of the apple blossom beetle from wintering places, as well as the method of shaking off in the morning, at a temperature of no higher than 10˚С. The count of four-legged microscopic mites in the early spring period was carried out before the leaves blooming by the method of selecting the tops of annual growths up to 10 cm long, at 10 counting sites (to view the opening buds). During the growing season, 10 leaves were sampled (4 ... 5th leaves from the top of the shoot), at each registration area. The analysis of microscopic objects on the selected samples was carried out using an MBS-10 stereoscopic microscope. In the research area, new dangerous invasive apple phytophages were identified: corrosive arboreal tree Zeuzera pyrina L. (Lepidoptera: Cossidae), apple rusty mite Aculus schlechtendali Nalepa (Acariformes: Eriophyidae), apple felt mite Phyllocmespates malinus (Acariformes: Eriophyidae). The bioecology and harmfulness of autochthonous phytophages have changed significantly. The apple moth Cydia pomonella L. (Lepidoptera: Tortricidae) gives up to two generations, and the summer lasts up to 132 days. Red (Panonychus ulmi Koch. (Acariformes: Tetranychidae)) and brown (Bryobia redikorzevi Reck (Acariformes: Bryobiidae)) fruit mites, depending on weather conditions, develop in 4 ... 5 generations a year, common spider mite (Tetranychus urticae Koch. (Acariformes: Tetranychidae)) at 7. The prevalence of ticks reaches 100%, and the degree of damage to plants by them is up to 3-4 points. Damage to apple flowers by the weevil Anthonomus pomorum L. (Coleoptera: Curculionidae) reaches 60 ... 85%, the colonization of leaves and shoots by the red-gall aphid Dysaphis devecta Walk. (Homoptera: Aphididae) 35 ... 45%, fruit loss from apple sawfly Haplocampa testudinea Klug. (Hymenoptera: Tenthredinidae) 15%

Designing chemical micromotors that communicate-A survey of experiments

Micromotors that communicate with their neighbors or with the environment are useful in a wide variety of applications, especially those involving complicated tasks that require coordination. A biomimetic strategy for achieving this goal is via chemical communication, where chemical signals released from one motor is transmitted through the medium and induce a specific response from a second motor. In this article, we review the recent experimental progress on this front. We first introduce three common strategies for releasing chemicals from a microscopic object, via diffusion, physical/chemical stimuli, or gated control, that form the cornerstone for designing communicating micromotors. We then review three levels of chemical communication of micromotors in order of ascending complexity, starting with cases where micromotors attract or repel inert tracers, to the unidirectional signal transmission between two motors of different types, and finally to the reciprocal (bidirectional) communication between two motors that often lead to higher-order assemblies. This review article ends with a perspective of the challenges and opportunities with communicating micromotors, which could inspire more sophisticated designs of in-depth communication between motors with different functions.

Agglomeration of particles by a converging ultrasound field and their quantitative assessments

The acoustic radiation force resulting from acoustic waves has been extensively studied for the contact-free generation of organized patterns. Microscopic objects normally cluster at pressure nodes, but the size of the clusters is restricted by the saturation limit. Here, we present a two-dimensional bulk acoustic wave (BAW) device to propel particles of various sizes. It is shown experimentally that, when particles are large, significant acoustic energy is scattered and is partly absorbed by the matched layers in front of the sensors. The acoustic radiation force then forms a convergent acoustic pressure field which agglomerates the large polystyrene (PS) particles towards the central region instead of the pressure nodes. The transition from the nodal-array patterns to the central agglomeration depends on particle size, particle concentration, and load voltage. A parametric study reveals that the particles can agglomerate with a cluster ratio greater than 70%, and this ratio can be improved by increasing the load power/voltage supplied to the transducers. With its ability to perform biocompatible, label-free, and contact-free self-assembly, the device introduced offers a new possibility in the fabrication of colloidal layers, the recreation of tissue microstructure, the development of organoid spheroid cultures, the migration of microorganisms, and the assembly of bioprinting materials.

Simulation and analysis of variable numerical aperture wide-field microscopy for telecentricity with constant resolution

In this work, we propose simulation and analysis of a novel combination of a variable numerical aperture wide-field microscope objective with an Electrically Tunable Lens (ETL) for axial scanning with a telecentric image space. This work resolves the challenges of the conventional ETL based wide-field microscopic systems viz. variable magnification, field-of-view (FOV), an inconsistent lateral and axial resolution. The proposed combination performs the tuning of the object plane by changing ETL current and effectively modifies the object space numerical aperture using an aperture controller to provide a stationary telecentric image plane. Moreover, with the proposed combination, the lateral resolution of the system is preserved over an axial range of 7.586mm with a magnification error of 2.55 %. The proposed work witnesses the advantages of providing fast axial scanning, extended axial scanning range, autofocusing, invariant magnification, constant FOV, and constant resolution along with a compact optical setup.

Label-free super-resolution imaging below 90-nm using photon-reassignment

Background: Achieving resolutions below 100 nm is key for many fields, including biology and nanomaterial characterization. Although nearfield and electron microscopy are the gold standards for studying the nanoscale, optical microscopy has seen its resolution drastically improve in the last decades. So-called super-resolution microscopy is generally based on fluorescence photophysics and requires modification of the sample at least by adding fluorescent tags, an inevitably invasive step. Therefore, it remains very challenging and rewarding to achieve optical resolutions beyond the diffraction limit in label-free samples. Methods: Here, we present a breakthrough to unlock label-free 3D super-resolution imaging of any object including living biological samples. It is based on optical photon-reassignment in confocal reflectance imaging mode. Results: We demonstrate that we surpass the resolution of all fluorescence-based confocal systems by a factor ~1.5. We have obtained images with a 3D (x,y,z) optical resolution of (86x86x248) nm3 using a visible wavelength (445 nm) and a regular microscope objective (NA=1.3). The results are presented on nanoparticles as well as on (living) biological samples. Conclusions: This cost-effective approach double the resolution of reflectance confocal microscope with minimal modifications. It is therefore compatible with any microscope and sample, works in real-time, and does not require any signal processing.

Super-Resolution Enhancement Method Based on Generative Adversarial Network for Integral Imaging Microscopy.

The integral imaging microscopy system provides a three-dimensional visualization of a microscopic object. However, it has a low-resolution problem due to the fundamental limitation of the F-number (the aperture stops) by using micro lens array (MLA) and a poor illumination environment. In this paper, a generative adversarial network (GAN)-based super-resolution algorithm is proposed to enhance the resolution where the directional view image is directly fed as input. In a GAN network, the generator regresses the high-resolution output from the low-resolution input image, whereas the discriminator distinguishes between the original and generated image. In the generator part, we use consecutive residual blocks with the content loss to retrieve the photo-realistic original image. It can restore the edges and enhance the resolution by ×2, ×4, and even ×8 times without seriously hampering the image quality. The model is tested with a variety of low-resolution microscopic sample images and successfully generates high-resolution directional view images with better illumination. The quantitative analysis shows that the proposed model performs better for microscopic images than the existing algorithms.

Microscope objectives

Microscope objectives are key components of optical microscopes, but they also equip experimental set-ups to focus laser beams or to collect photons emitted from any physical events to analyze or to diagnose. There are properties to take into account about their specifications and their usage for selecting the right microscope objective. They are used in a wide range of applications, from life sciences to material sciences, in laboratories and in industries and each application requires a specific microscope objective.

Can Macroscopic Objects Entanglement and Microscopic Objects Entanglement Be Entangled Simultaneously?

In this paper, we propose a simple method to simultaneously generate the entanglement between macroscopic objects (mechanical oscillators) and entanglement between microscopic objects (photons) based on a coupled cavity-optomechanical system. We show that when the cavity-optomechanical system works in the single-photon strong-coupling regime and in the deep quantum regime, the radiation pressure of a photon which is created by the atom-cavity interaction, can directly induce these joint entangled states. Thus, no measurement on this system is required. Numerical simulation shows that the fidelity of the prepared joint entangled states can reach 0.954.

Depth Hypotheses Fusion through 3D Weighted Least Squares in Shape from Focus.

In shape-from-focus (SFF) methods, a single focus measure is used to compute the focus volume. However, it seems that a single focus measure operator is not capable of computing accurate focus values for the images of diverse types of object shapes. Furthermore, most of the SFF methods try to improve the depth map without considering any additional structural or prior information. Consequently, the extracted shape of the object might lack important details. In this work, we address these problems and suggest a method in which depth hypotheses are combined for a more accurate 3D shape through 3D weighted least squares. First, depth hypotheses are obtained by applying a number of focus operators. Then, structural prior or guidance volume is extracted from the focus measure volumes. Finally, a 3D weighted least squares optimization technique is applied to the depth hypothesis volume, where weights are computed from the guidance volume. Thus, by inducing structural prior, an improved resultant depth map is obtained. The proposed method was tested using various image sequences of synthetic and microscopic real objects. Experimental results and comparative analysis demonstrated the effectiveness of the proposed method.

Optical Design of A CaF2-free 5× Flat-field Apochromatic Metallographic Micro-objective with Long Working Distance

Based on the apochromatic system theory, an innovative CaF2-free 5× plan apochromatic metallographic micro-objective with long working distance was designed using the OSLO software through the iterative optimization technique. The designed metallographic microscope objective used the relevant photographic field lens as the initial structure. The final lens structure is composed of 7 lenses of 4 components in coaxial array. The object surface is imaged at infinity through an optical system. According to analysis results of the design, this metallographic microscope objective has following characteristics. Firstly, all lens are CaF2-free and manufactured by optical glass produced. Secondly, it can achieve flat-field chromatic aberration. Thirdly, it has a large field of view and long working distance.

Accelerating 3D single-molecule localization microscopy using blind sparse inpainting.

.Significance: Single-molecule localization-based super-resolution microscopy has enabled the imaging of microscopic objects beyond the diffraction limit. However, this technique is limited by the requirements of imaging an extremely large number of frames of biological samples to generate a super-resolution image, thus requiring a longer acquisition time. Additionally, the processing of such a large image sequence leads to longer data processing time. Therefore, accelerating image acquisition and processing in single-molecule localization microscopy (SMLM) has been of perennial interest.Aim: To accelerate three-dimensional (3D) SMLM imaging by leveraging a computational approach without compromising the resolution.Approach: We used blind sparse inpainting to reconstruct high-density 3D images from low-density ones. The low-density images are generated using much fewer frames than usually needed, thus requiring a shorter acquisition and processing time. Therefore, our technique will accelerate 3D SMLM without changing the existing standard SMLM hardware system and labeling protocol.Results: The performance of the blind sparse inpainting was evaluated on both simulation and experimental datasets. Superior reconstruction results of 3D SMLM images using up to 10-fold fewer frames in simulation and up to 50-fold fewer frames in experimental data were achieved.Conclusions: We demonstrate the feasibility of fast 3D SMLM imaging leveraging a computational approach to reduce the number of acquired frames. We anticipate our technique will enable future real-time live-cell 3D imaging to investigate complex nanoscopic biological structures and their functions.

In memory of Arthur Ashkin

Radiation pressure exerted by light was a lifelong passion for Arthur Ashkin. He foresaw that light pressure could do useful work and invented the optical tweezers that can trap microscopic objects, from small ‘living things’ down to individual atoms.

Intensity-based holographic imaging via space-domain Kramers–Kronig relations

Holography is a powerful tool to record waves without loss of information that has benefited optical, X-ray and electronic imaging applications by quantifying phase delays induced by light–matter interactions. However, holographic imaging is technically demanding in that it generally requires an interferometric setup, a coherent source and long-term stability. Here, we present holographic imaging in which a phase image is obtained directly from a single intensity measurement in oblique illumination. Our approach is based on space-domain Kramers–Kronig relations that transform the spatial variation in intensity to the spatial variation in phase. We demonstrate two-dimensional holographic imaging and three-dimensional refractive index tomography of microscopic objects and biological specimens from intensity images measured with an optical microscope and illumination control. The proposed method does not require iterative processes nor strict constraints and opens up a new approach to non-interferometric holographic imaging in various spectral regimes. An intensity-based holographic imaging via space-domain Kramers–Kronig relations is presented, allowing the phase image of an object to be obtained directly from a single intensity measurement with oblique illumination.

Two-color differential dynamic microscopy for capturing fast dynamics.

Differential dynamic microscopy (DDM) is increasingly used in the fields of soft matter physics and biophysics to extract the dynamics of microscopic objects across a range of wavevectors by optical microscopy. Standard DDM is limited to detecting dynamics no faster than the camera frame rate. We report on an extension to DDM where we sequentially illuminate the sample with spectrally distinct light and image with a color camera. By pulsing blue and then red light separated by a lag time much smaller than the camera's exposure time, we are able to use this two-color DDM method to measure dynamics occurring much faster than the camera frame rate.

High-speed multicolor structured illumination microscopy using a hexagonal single mode fiber array.

Structured illumination microscopy (SIM) is a widely used imaging technique that doubles the effective resolution of widefield microscopes. Most current implementations rely on diffractive elements, either gratings or programmable devices, to generate structured light patterns in the sample. These can be limited by spectral efficiency, speed, or both. Here we introduce the concept of fiber SIM that allows for camera frame rate limited pattern generation and manipulation over a broad wavelength range. Illumination patterns are generated by coupling laser beams into radially opposite pairs of fibers in a hexagonal single mode fiber array where the exit beams are relayed to the microscope objective's back focal plane. The phase stepping and rotation of the illumination patterns are controlled by fast electro-optic devices. We achieved a rate of 111 SIM frames per second and imaged with excitation patterns generated by both 488 nm and 532 nm lasers.

Organic biomorphs may be better preserved than microorganisms in early Earth sediments

Abstract The Precambrian rock record contains numerous examples of microscopic organic filaments and spheres, commonly interpreted as fossil microorganisms. Microfossils are among the oldest traces of life on Earth, making their correct identification crucial to our understanding of early evolution. Yet, spherical and filamentous microscopic objects composed of organic carbon and sulfur can form in the abiogenic reaction of sulfide with organic compounds. Termed organic biomorphs, these objects form under geochemical conditions relevant to the sulfidic environments of early Earth. Furthermore, they adopt a diversity of morphologies that closely mimic a number of microfossil examples from the Precambrian record. Here, we tested the potential for organic biomorphs to be preserved in cherts; i.e., siliceous rocks hosting abundant microbial fossils. We performed experimental silicification of the biomorphs along with the sulfur bacterium Thiothrix. We show that the original morphologies of the biomorphs are well preserved through encrustation by nano-colloidal silica, while the shapes of Thiothrix cells degrade. Sulfur diffuses from the interior of both biomorphs and Thiothrix during silicification, leaving behind empty organic envelopes. Although the organic composition of the biomorphs differs from that of Thiothrix cells, both types of objects present similar nitrogen/carbon ratios after silicification. During silicification, sulfur accumulates along the organic envelopes of the biomorphs, which may promote sulfurization and preservation through diagenesis. Organic biomorphs possessing morphological and chemical characteristics of microfossils may thus be an important component in Precambrian cherts, challenging our understanding of the early life record.

Laser scanning dark-field coherent anti-Stokes Raman scattering (DF-CARS): a numerical study.

We present and model a dark-field illumination scheme for coherent anti-Stokes Raman scattering (DF-CARS) that highlights the interfaces of an object with chemical sensitivity. The proposed DF-CARS scheme uses dedicated arrangements of the pump kp1, Stokes kS and probe kp2 beams' k-wave-vectors to address the sample's interfaces along the x, y or z axis. The arrangements of the incident k-wave-vectors are derived from the Ewald sphere representation of the outgoing anti-Stokes radiation and the effective CARS excitation wave-vector keff = kp1 + kp2 - kS under the intention to avoid probing the object frequency K(0,0,0), i.e., the contribution of a homogeneous sample (dark-field configuration). We suggest a possible experimental realization using simple masks placed in the back pupil of the excitation microscope objective lens. Applying a full vectorial model, the proposed experimental implementation is numerically investigated on grounds of the Debye-Wolff integral and dynadic Green function to confirm the predicted chemical interface contrast.

Femtosecond laser single step, full depth cutting of thick silicon sheets with low surface roughness

Separation of silicon wafers is an integral part of semiconductor device manufacture. The widely used mechanical separation methods produce large kerf widths and micro-cracks. Existing laser separation, singulation and dicing methods can reduce cutting kerf widths, but usually involve multiple steps. Although single step laser through cutting by ablation has been reported before, surface roughness is usually poor. This paper presents a method for single step, full-depth cutting of silicon wafer sheets of 200 µm in thickness with an 800 nm wavelength femtosecond-pulse laser focused using a microscope objective lens under ambient condition. By introducing parallel scan lines, through cut is realized with an excellent sidewall full area roughness of 191 nm Ra, which is much better than that of reported previously in laser through-cutting of thick silicon sheets of similar thickness. It is found that by increasing the number of overscan, pulse energy, or number of parallel scan lines, the sidewall surface roughness reduces and the kerf edge straightness at the bottom surface is improved. The effects of p- and s-polarization on cutting quality are compared. Sidewall quality can be improved by appropriate selection of beam polarization and cutting speed. The mechanisms involved are discussed.

Meta-objective with sub-micrometer resolution for microendoscopes

Microendoscopes are vital for disease detection and clinical diagnosis. The essential issue for microendoscopes is to achieve minimally invasive and high-resolution observations of soft tissue structures inside deep body cavities. Obviously, the microscope objective is a must with the capabilities of both high lateral resolution in a wide field of view (FOV) and miniaturization in size. Here, we propose a meta-objective, i.e., microscope objective based on cascaded metalenses. The two metalenses, with the optical diameters of 400 μm and 180 μm, respectively, are mounted on both sides of a 500-μm-thick silica film. Sub-micrometer lateral resolution reaches as high as 775 nm in such a naked meta-objective, with monochromatic aberration correction in a 125 μm full FOV and near diffraction limit imaging. Combined with a fiber bundle microscope system, the single cell contour of biological tissue (e.g., water lily leaf) can be clearly observed, compared to the indistinguishable features in other conventional lens-based fiber bundle systems, such as plano–convex and gradient refractive index (GRIN) cases.

Simulations and experimental demonstration of three different regimes of optofluidic manipulation.

It has been demonstrated that optically controlled microcurrents can be used to capture and move around a variety of microscopic objects ranging from cells and nanowires to whole live worms. Here, we present our findings on several new regimes of optofluidic manipulation that can be engineered using careful design of microcurrents. We theoretically optimize these regimes using COMSOL Multiphysics and present three sets of simulations and corresponding optofluidic experiments. In the first regime, we use local fluid heating to create a microcurrent with a symmetric toroid shape capturing particles in the center. In the second regime, the microcurrent shifts and tilts because external fluid flow is introduced into the microfluidic channel. In the third regime, the whole microfluidic channel is tilted, and the resulting microcurrent projects particles in a fan-like fashion. All three configurations provide interesting opportunities to manipulate small particles in fluid droplets and microfluidic channels.