Contrast Microscopy Images Research Articles

Highly focused beam generated with a height tuned micro-optical structure for high contrast microscopic imaging

Light sheet illumination technology improves the signal-to-noise ratio, resolution, and reduces scattered backgrounds for biological microscopic detection system. Here, we developed a novel micro-optical structure to produce a focused and uniform beam for the enhancement of imaging contrast. The beam intensity and working distance can be modified by adjusting the height and period of the structure. Our experiments successfully recorded structured light illumination, demonstrating the ability of the structure to capture high-contrast imaging data. We compared the light fields generated with and without the structure to assess the imaging quality, revealing a maximum 4.78-fold improvement in the signal-to-noise ratio. This work provides a potential method for high-resolution and high-contrast light sheet fluorescence microscopic detection.

A deep learning-based pipeline for analyzing the influences of interfacial mechanochemical microenvironments on spheroid invasion using differential interference contrast microscopic images

Metastasis is the leading cause of cancer-related deaths. During this process, cancer cells are likely to navigate discrete tissue-tissue interfaces, enabling them to infiltrate and spread throughout the body. Three-dimensional (3D) spheroid modeling is receiving more attention due to its strengths in studying the invasive behavior of metastatic cancer cells. While microscopy is a conventional approach for investigating 3D invasion, post-invasion image analysis, which is a time-consuming process, remains a significant challenge for researchers. In this study, we presented an image processing pipeline that utilized a deep learning (DL) solution, with an encoder-decoder architecture, to assess and characterize the invasion dynamics of tumor spheroids. The developed models, equipped with feature extraction and measurement capabilities, could be successfully utilized for the automated segmentation of the invasive protrusions as well as the core region of spheroids situated within interfacial microenvironments with distinct mechanochemical factors. Our findings suggest that a combination of the spheroid culture and DL-based image analysis enable identification of time-lapse migratory patterns for tumor spheroids above matrix-substrate interfaces, thus paving the foundation for delineating the mechanism of local invasion during cancer metastasis.

Antibacterial and Anti-inflammatory Activity of Extracts and Major Constituents Derived from Stachytarpheta indica Linn. Leaves and Their Potential Implications for Wound Healing.

Wounds of various types continue to have a severe socioeconomic impact on the cost of health care. Globally, there has been increased interest surrounding the identification of bioactive compounds that promote or modulate the wound healing process. Stachytarpheta indica Linn. is traditionally used to heal wounds and relieve inflammation; however, the theorised pharmacological properties have not yet been scientifically validated. In this study, dried and ground plant leaves were extracted with water and methanol, which were then subjected to various analyses. The antimicrobial activity of the plant extracts and isolated compounds was determined using well diffusion assays, while the minimum inhibitory concentrations were determined with a colorimetric assay. Morphological changes of human keratinocytes in response to plant extracts were observed with differential interference contrast microscope imaging. Cell viability, proliferation, and migratory effects post-treatment with the plant extracts were also evaluated via colorimetric cytotoxicity assays and a real-time cell analyser protocol. Anti-inflammatory effects of plant extracts and isolated compounds were evaluated by flow cytometry and cyclooxygenase and lipoxygenase enzyme inhibition assays. Three active compounds, i.e. ipolamiide, verbascoside and iso-verbascoside, were isolated from S. indica leaves. Verbascoside demonstrated broad-range antibacterial activity and imposed strong inhibition at 9.77μg/mL against Staphylococci spp. S. indica extracts (0.1-0.2mg/mL) were shown to improve human keratinocyte proliferation up to 60% and induce morphological changes by producing cytoplasmic projections at concentrations higher than 0.4mg/mL. Plant extracts (6.25-100μg/mL) and individual compounds (3.125-50μg/mL) elicited strong anti-inflammatory effects by suppressing the expression of interleukin-8 and inhibiting cyclooxygenase-1 and 5-lipoxygenase enzymes. Collectively, these results indicate that plant extracts and isolated compounds derived from S. indica have the potential to inhibit bacterial growth, promote tissue regeneration and reduce inflammation, hence, potentially providing the basis for a novel therapeutic for the treatment of wounds.

Lineage Tracking and Differentiation of Neuro 2A cells (N2a) upon exposure to Dopamine, Monosodium Glutamate and Corticosterone

Cell to cell communication is critical for survival of an organism and it is achieved through signal transduction pathways. For the transmission of signal, molecules such as hormones can bind to a receptor on or inside the cell membrane. Dopamine (DA) a monoamine catecholamine neurotransmitter and hormone binds to dopamine receptor, inturn, affect movement, emotions and the reward system in the brain. The present study tested the hypothesis that Dopamine differentiates the N2a cells into neuronal lineage, and corticosterone (CORT) and monosodium glutamate (MSG) alter the differentiation in either way. Mouse neural crest‐derived cell line (Neuro2A cells, N2a cells) were treated with 10µM DA, MSG and CORT. Cells were seeded for different time points to track the lineage pattern of differentiation. Treatment was done for 24 hrs, 48 hrs, 72hrs and 96 hrs with respective control groups. Phase contrast microscopic images revealed that Dopamine treated cells showed neurite extensions and differentiation as time passed whereas CORT and MSG treatments suppressed the differentiation; the cells were round and showed signs of stress, cell death and autophagy. Immunocytochemical analysis with D1 receptor antibody indicated enhanced expression in the DA groups and diminished D1 receptor expression in CORT and MSG groups. Furthermore, quantitative analysis revealed that D1 receptor expression was significantly enhanced in DA group compared to the control group (medium containing ascorbic acid and phosphate buffered saline) and untreated control group (medium only). Interestingly D1 receptor expression in the DA group was significantly upregulated compared to the CORT group but not significantly different in the MSG group. Furthermore, inorder to assess apoptosis AnnexinV/Propidium Iodide (PI) staining was done using Fluorescence Assorted single cell sorter (FACS) Analysis. Immunolabeling with Caspase‐3 marker gene was done to detect apoptosis. N2a cells were treated with DA, CORT and MSG at 10 µM concentration for 24 hrs. Propidium iodide labelled cells that were already dead or in the late stage of apoptosis whereas Annexin V bound to the cells early in apoptosis and continued to be bound through cell death. Counting of the cells showed that MSG induced 1.8 % apoptosis, CORT induced 1.2 % and DA induced 1.1%, as against control group cells of 0.7 %. The total cell death including apoptosis and necrosis was highest in the MSG group (3.4%) compared to the control (1.7 %), DA (2.1%) and CORT (1.9%) treated groups. This data suggest differential effects elicited by DA (happy hormone) versus stress hormone. Our results also raise the question whether DA induces catecholaminergic pathway of differentiation, CORT stimulates glial type differentiation and MSG stimulates glutamate or GABA differentiation ‐ questions to be answered in future studies.

Investigation of a new modulated aperture using speckle techniques

BackgroundA design of equally spaced eight-circles placed at equal distances from the origin is suggested. Three models corresponding to the eight-circle design considering conic, linear, and quadratic distributions are investigated. This arrangement is considered for the sake of improving both microscope resolution and image contrast as compared with the pure annular aperture. This design is different compared with other recent work on aperture modulation.Results and discussionsThe point spread function (PSF) is computed in all the models using the fast Fourier transform (FFT) algorithm that computes the discrete Fourier transform (DFT) corresponding to the models and compared with the corresponding PSF in the case of uniform circular aperture. In addition, the autocorrelation images for the apertures are shown differently. It is shown smooth pattern for the circular arrangement as compared with the deformation and shrinking appeared in the central peak in case of conic model. Finally, the speckle images corresponding to the considered apertures are investigated. Reconstructed apertures are obtained from the speckle images using the FFT algorithm.ConclusionsThe PSF is computed for the described models, and the autocorrelation corresponding to the apertures showed difference. The reconstructed apertures from the speckle images can be improved using filtering techniques. It is noted that MATLAB codes are constructed in the computations of all images and plots.

BLOOD FLOW CONDITION IN LOWER EXTREMITY VESSELS AND ENDOTHELIAL DYSFUNCTION IN PATIENTS WITH TYPE 2 DIABETES MELLITUS DEPENDING ON DISEASE DURATION

The purpose of the study. Study arterial blood flow and blebbing of the plasma membrane of lymphocytes in the neuroischemic form of diabetic foot syndrome (SDS) depending on the age of the disease.
 Material and methods. In a prospective study, 150 patients of type 2 DM were examined, of which 50 people with a neuroischemic form of SDS. Blood flow condition on vessels of lower extremities and plasma membrane of lymphocytes was examined. There were 30 women (60%), 20 men (40%). Vascular channel condition was evaluated by ultrasound dopplerography of lower extremity arteries, degree of diabetes mellitus compensation was determined by glycated hemoglobin level, lymphocyte membrane condition was evaluated by phase contrast microscope imaging results.
 Results of the study. 72% of patients had complete occlusion of the tibia-foot segment of the arteries of the lower extremity, 28% had stenosis. The glycated hemoglobin level averaged 10.3 [8.5; 14.3]%, i.e. all observed patients had insufficient compensation for carbohydrate metabolism disorders. The total and terminal lymphocyte blebbing was 30.1 [25.4; 33.2]% and 15.8 [11.8; 18.4]%, which was 3 and 5 times higher than the control group, respectively. A high positive correlation between the duration of DM disease and the total (rS=0,72; p = 0.001) and terminal (rS=0,78; p = 0.001) blebbing of lymphocyte membrane.
 Conclusion. The high correlation between the timing of DM disease and the blebbing of the lymphocyte plasma membrane allows these indicators to be used as markers of endothelial dysfunction in neuroischemic and ischemic forms of SDS. The level of summary and terminal blebbing can be considered as a prognostic marker of the development of macroangiopathy in patients with type 2 DM.

A Novel Method for Effective Cell Segmentation and Tracking in Phase Contrast Microscopic Images.

Cell migration plays an important role in the identification of various diseases and physiological phenomena in living organisms, such as cancer metastasis, nerve development, immune function, wound healing, and embryo formulation and development. The study of cell migration with a real-time microscope generally takes several hours and involves analysis of the movement characteristics by tracking the positions of cells at each time interval in the images of the observed cells. Morphological analysis considers the shapes of the cells, and a phase contrast microscope is used to observe the shape clearly. Therefore, we developed a segmentation and tracking method to perform a kinetic analysis by considering the morphological transformation of cells. The main features of the algorithm are noise reduction using a block-matching 3D filtering method, k-means clustering to mitigate the halo signal that interferes with cell segmentation, and the detection of cell boundaries via active contours, which is an excellent way to detect boundaries. The reliability of the algorithm developed in this study was verified using a comparison with the manual tracking results. In addition, the segmentation results were compared to our method with unsupervised state-of-the-art methods to verify the proposed segmentation process. As a result of the study, the proposed method had a lower error of less than 40% compared to the conventional active contour method.

Stigmaeus exilis, a new fusiform species of Stigmaeus Koch (Acariformes: Stigmaeidae) from Sansa, Turkey

A new species of the genus Stigmaeus (Stigmaeidae), S. exilis sp. nov., is described based on the adult females collected from soil in a dead walnut tree hollow from Sansa Gorge, Turkey. Illustrations and phase contrast microscopic images of the new species are also given here. This species can be distinguished by having thin and slender body, anterior margin of prodorsum microtuberculate, posterior margin of propodosomal shield indenting forward by striae, apodemal marking present, eyes and postocular bodies absent, median zonal shield entire, suranal shield entire and bearing three pairs of setae, and femur II with four setae.

Refining Concrete’s micro-structure by enzymatically-induced carbonate precipitation through urease activity of bacteria

This paper presents the mechanism of improving the microstructure of concrete by enzymatically-induced carbonate precipitation through urease activity of bacteria Sporosarcina pasteurii. This calcium carbonate or calcite crystal precipitated during the biological activity fills the pores in the concrete imparting the concrete the dense microstructure. The presence of 105 per milliliter of mixing water yields high compressive strength due to precipitation of highest amount of calcium crystals in the concrete pores thereby plugging the micro and macro pores in the concrete refining the micro-structure of the concrete. SEM images, XRD plots and thermo-gravimetric analysis confirmed the presence of calcite mineral in the bacterial mortar specimens. The presence of spores of Sporosarcina pasteurii in the bacterial mortar specimens of 365 days old are found through phase contrast microscopic images. This confirms the sporulation ability of bacteria Sporosarcina pasteurii. Concrete specimens induced with bacteria showed considerably less water absorption capacity compared to normal specimens. This decrease in water absorption capacity of bacteria induced concretes is credited to the reduction of pores in the concrete due to calcite mineral precipitation filling the pores reducing the typical pore radius of concrete. Average pore diameter in bacteria incorporated concrete decreases drastically due to calcite mineral precipitation in the pores because of microbial metabolic activity. The total pore volume also decreased in case of bacteria incorporated concrete samples.

Transcriptomic and Morphological Analysis of Cells Derived from Porcine Buccal Mucosa-Studies on an In Vitro Model.

Simple SummaryDomestic pigs express high phylogenetic similarity to humans and are often used as a compatible model in biomedical research. Porcine tissues are used as an accessible biomaterial in human skin transplants and tissue architecture reconstruction. We used transcriptional analysis to investigate the dynamics of complex biological system of the mucosa. Additionally, we performed computer analysis of microscopic images of cultured cells in vitro. Computer analysis of images identified epithelial cells and connective tissue cells in in vitro culture.Transcriptional analysis and live-cell imaging are a powerful tool to investigate the dynamics of complex biological systems. In vitro expanded porcine oral mucosal cells, consisting of populations of epithelial and connective lineages, are interesting and complex systems for study via microarray transcriptomic assays to analyze gene expression profile. The transcriptomic analysis included 56 ontological groups with particular focus on 7 gene ontology groups that are related to the processes of differentiation and development. Most analyzed genes were upregulated after 7 days and downregulated after 15 and 30 days of in vitro culture. The performed transcriptomic analysis was then extended to include automated analysis of differential interference contrast microscopy (DIC) images obtained during in vitro culture. The analysis of DIC imaging allowed to identify the different populations of keratinocytes and fibroblasts during seven days of in vitro culture, and it was possible to evaluate the proportion of these two populations of cells. Porcine mucosa may be a suitable model for reference research on human tissues. In addition, it can provide a reference point for research on the use of cells, scaffolds, or tissues derived from transgenic animals for applications in human tissues reconstruction.

Toward high contrast and high-resolution microscopic ghost imaging.

In this study, the influence of speckle size on contrast-to-noise ratio (CNR) and resolution is examined based on the object dimensions in the macroscopic and microscopic regimes. This research shows that for microscopic samples the conventional scaling laws are no longer effective and the CNR does not counter-propagate in the same manner as the resolution. To our knowledge, a deviation in CNR scaling on speckle size is observed for the first time in the field of microscopic ghost imaging. This result was verified using two different sample shapes. In addition, numerical analysis revealed that the noise of the photodiode is a limiting factor for the CNR. Based on these findings, the conditions for identifying the parameter set that maximizes the CNR and provides high resolution images was defined, which achieving high-quality microscopic ghost images.

Molecular Detection of Cordycepin-Induced HeLa Cell Apoptosis with Surface-Enhanced Raman Spectroscopy

Cordycepin, extracted from the medicinal mushroom Cordyceps militaris, was shown to induce cancer cell apoptosis. Yet its anticancer function was limitedly evaluated, and the mechanism was not entirely elucidated. In this study, we demonstrated the effectiveness of cordycepin in inducing apoptosis in HeLa cells and investigated its apoptosis-inducing mechanism through label-free surface-enhanced Raman spectroscopy (SERS). SERS spectral changes revealed detailed molecular changes in both early and late stages of apoptosis. Importantly, SERS characteristic peaks at 805 and 1438 cm−1, which were assigned to RNA, continued to decrease significantly from early to late apoptosis stages. It indicated that cordycepin induced HeLa cell apoptosis mainly through interfering with RNA production, potentially by restraining the translation of RNA encoding ribosomal proteins. Meanwhile, apoptotic cells and their apoptosis stage could be easily differentiated by SERS-based principal component analysis (PCA). Furthermore, the morphological changes of early and late-stage apoptotic cells were illustrated by differential interference contrast and fluorescence microscopic imaging. Therefore, the natural ingredient, cordycepin, could serve as a promising anticancer candidate. Our biological model of cell apoptosis in vitro, the non-invasive and rapid SERS technique, combined with PCA analysis, could be a powerful tool in the investigation of cell apoptosis mechanisms and anticancer drug screening.

MON-003 Relationship between urinary podocytes and urinary protein fraction evaluated by SDS-PAGE

Urinary podocyte excretion is associated with a reduction in glomerular podocyte number, glomerular sclerosis and urine protein selectivity.In the patients undergoing renal biopsy we examined the relationship between urinary podocytes and urinary protein fraction separated by SDS-polyacrylamide gel electrophoresis (PAGE). Urine sediment was stained with fluorescently labeled podocalyxin antibody and cells superimposed with phase contrast microscopic images were counted. The amount of protein bands separated by SDS-PAGE was calculated by NIH Image-J software and correlation with urine podocytes was examined. Urinary podocyte numbers were significantly correlated with amount of Tamm-Horsfall Protein (MW95kD, R=0.74, p<0.001), albumin (MW67kD, R=0.66, p<0.001), prealbumin (MW55kD, R=0.55, p<0.005) and transferrin (MW80kD, R=0.41, p<0.05). However, there were no significant correlation between urinary podocyte number and β２-microglobulin（MW12kD, R=0.14, p=0.49）, light chain (MW23kD, R=0.14, p=0.47), α１-microglobulin (33kD,R=0.056, p=0.78), IgG(MW160kD, R=0.09, p=0.64), IgG/Tf (R=0.11, p=0.57), or IgG/Alb (R=0.14, p=0.48). Urinary podocyte often contained lipid droplets in the vesicles. In conclusion, urinary podocyte excretion was correlated with urinary albumin and transferrin filtration and tubular excretion of THP.

Live-cell imaging of macrophage phagocytosis of asbestos fibers under fluorescence microscopy

BackgroundFrustrated phagocytosis occurs when an asbestos fiber > 10 μm in length is engulfed imperfectly by a macrophage, and it is believed to be associated with chromosomal instability. Few studies have focused on dynamic cellular imaging to assess the toxicity of hazardous inorganic materials such as asbestos. One reason for this is the relative lack of fluorescent probes available to facilitate experimental visualization of inorganic materials. We recently developed asbestos-specific fluorescent probes based on asbestos-binding proteins, and achieved efficient fluorescent labeling of asbestos.ResultsLive-cell imaging with fluorescent asbestos probes was successfully utilized to dynamically analyze asbestos phagocytosis. The fluorescently labeled asbestos fibers were phagocytosed by RAW 264.7 macrophages. Internalized fibers of < 5 μm in length were visualized clearly via overlaid phase contrast and fluorescence microscopy images, but they were not clearly depicted using phase contrast images alone. Approximately 60% of the cells had phagocytosed asbestos fibers after 2 h, but over 96% of cells remained alive even 24 h after the addition of asbestos fibers. Immediate cell death was only observed when an asbestos fiber was physically pulled from a cell by an external force. Notably, at 24 h after the addition of asbestos fibers an approximately 4-fold increase in the number of binucleated cells was observed. Monitoring of individual cell divisions of cells that had phagocytosed asbestos suggested that binucleated cells were formed via the inhibition of cell separation, by asbestos fibers of > 10 μm in length that were localized in the proximity of the intercellular bridge.ConclusionsFluorescently labeled asbestos facilitated visualization of the dynamic biological processes that occur during and after the internalization of asbestos fibers, and indicated that (i) frustrated phagocytosis itself does not lead to immediate cell death unless the asbestos fiber is physically pulled from the cell by an external force, and (ii) macrophages that have phagocytosed asbestos can divide but sometimes the resulting daughter cells fuse, leading to the formation of a binucleated cell. This fusion only seemed to occur when a comparatively long asbestos fiber (> 10 μm) was shared by two daughter cells.

Morphological Modification of Carbon Nanoparticles after Interacting with Methotrexate as a Potential Anticancer Agent.

Production of highly penetrable and targetable drug delivery particles is mainly focused by current therapy and such focus is achieved in our present study. The carbon nanoparticle (CNP) prepared from purely natural source was modified from spherical shape to cylindrical floral like structure after treatment with the anticancer drug methotrexate (CM). The physiochemical properties of the CNP and CM was characterized using FT-IR/Raman Spectrometer, XRD, SEM, AFM, particle size analyzer and its biological evaluation using haemolysis and MTT assay. The shift in FT-IR peaks at 1592, 1120cm-1 and peaks of raman spectra observed at 1303, 1300cm-1 represents ordered carbon nanotubes. The morphological change from spherical to cylindrical floral like structure was observed using SEM and AFM and its particle size distribution analysis shows an average diameter of 269nm for CM. XRD peak at 2θ = 23.86° (002) indicates the presence of large amount of amorphous material that corresponds to multi-walled carbon nanotubes. Haemocompatibility studies proved the safety level usage as 100μg/ml and MTT assay shows viability rate of 85-98% with mouse embryonic fibroblast (NIH/3T3) and 30-45% with pancreatic carcinoma (MIA PaCa-2) and gastric cancer cell lines (SNU- 484) respectively.These results are also supported by phase contrast microscope images observed after staining with calcein AM and EthD-1. The morphologically modified CNPs has shown good anticancer, biocompatibility and haemocompatibility property which is an important criterion to be satisfied by a biomedical product.

&amp;lt;italic&amp;gt;In-situ&amp;lt;/italic&amp;gt; high-temperature mechanical property measurement technology and its application in scanning electron microscope

Scanning Electron Microscope (SEM) is an important observational device in scientific research. Over the past decades, scientists have been working on the high temperature deformation measurement and characterization of the critical alloy materials and components in hot sections by in situ observations with SEM. The in situ observations have both important theoretical and high engineering significance in understanding the mechanisms of the microstructure damage evolution of the alloys, understanding their high temperature failure mechanisms, extracting mechanical parameters and improving the accuracy of life prediction methods. However, in situ high temperature measurements in a SEM environment pose major challenges in high efficiency heat source design, establishment of stable high contrast microscopic images, and quantitative measurement of the deformation fields in high temperature environment. New methods and approaches must be therefore developed for measurement of mechanical properties in such harsh environment. In the study presented here, the major difficulties and challenges associated with high temperature experiments implemented in situ SEM are introduced firstly, especially the imaging failure at high temperature. The developments of high temperature in situ SEM technology in recent years are then reviewed, including high temperature in situ test instruments, high temperature imaging technology, and high temperature deformation measurement methods. On this basis, some new research results achieved by our group in the field of creep, fatigue and fracture of nickel based alloy materials at high temperature are introduced, such as the fatigue small and long crack growth behaviors at different temperature as well as in different crystallographic orientations. Nickel based alloy is the critical material for gas turbine and aero-engine due to their excellent creep, fatigue and corrosion resistance at high temperature. Finally, some conclusions of current development in this research field are presented, meanwhile works that need to be further extended in the future are also pointed out.

Conductive contact area estimation for carbon nanotube via interconnects using secondary-electron imaging

A major challenge for carbon nanotube (CNT) to become a viable replacement of copper and tungsten in the next-generation on-chip via interconnects is the high contact resistance between CNT and metal electrodes. A first step in meeting this challenge is an accurate characterization of via contact resistance. In this paper, the scanning electron microscope (SEM) image contrast at low landing energy is employed to estimate the conductive CNT area inside vias. The total conductive CNT area inside each via is deduced using SEM image with 0.1 keV landing energy and a specified threshold brightness, yielding via resistance versus CNT area behavior, which correlates well with electrical nanoprobing measurements of via resistance. Monte Carlo simulation of secondary electron generation lends further support for our analysis and suggests that the residue covering the CNT does not affect the conduction across the contact for residue thickness below 1 nm. This imaging and analysis technique can add much value to CNT via interconnect contact characterization.

Tailoring electrospun polymer blend carriers for nutrient delivery in seed coating for sustainable agriculture

The fabrication of ultrathin fibrous seed coating material with focus on improving the germination potential of the seed was the aim of this work. In this effort, we have fabricated electrospun Polyvinylpyrrolidone (PVP) - poly (diethoxy) phosphazene (PPZ) nanofibers. PVP is biocompatible, biodegradable and a commonly used seed coating material while PPZ is a nitrogen and phosphorus rich, hydrophobic polymer which undergoes 74% degradation in 12 weeks. Cowpea (Vigna unguiculata) seeds with a harvesting time of 90 days were used as test subject. Electrospinning confers water permeability, gaseous exchange and does not have residual solvent which is an advantage over film coats. The fabricated blends were characterised by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) etc and it showed partial compatibility of the polymers. The phase contrast microscopic images also showed two phases. A decrease in wettability with increase in the PPZ content in the fibers was seen from water contact angle measurements. The swelling and stability studies indicated that the presence of PPZ in the fibers helps retention of material on the seed. The seed viability and the degradation of the fibrous seed coating were studied using conductivity meter and pH meter. The observed experimental findings may be beneficial and of prospective use in sustainable agriculture. Such polymer blends have the potential to reduce water and soil pollution as well as protect the seed during storage and increase crop yield.

Phase-shifted helical long-period fiber grating and its characterization by using the microscopic imaging method.

We demonstrate a simple and robust method to write a phase-shifted helical long-period fiber grating (HLPG), where an equivalent phase-shift is formed by changing the local period of the grating during the fabrication process. Furthermore, we propose and demonstrate a simple method to characterize the phase-shift formed in a HLPG, which is realized by directly analyzing the imaging pattern of the fabricated HLPG using a stereo microscope under a white light illumination. Unlike the previous methods which are indirectly realized either by measuring the transmission spectrum of the fabricated HLPG or by analyzing the differential interference contrast (DIC) microscopic images of the fabricated HLPG, the proposed method can be used to well estimate the grating period as well as the phase-shift inserted in the HLPG in situ, which could considerably facilitate the fabrication technique of the HLPG by using CO2 laser.

Nuclear detection in 4D microscope images of a developing embryo using an enhanced probability map of top-ranked intensity-ordered descriptors

Abstract Nuclear detection in embryos is an indispensable process for quantitative analysis of the development of multicellular organisms. Due to the overlap in the distribution of pixel intensity of nuclear and cytoplasmic regions and the large variation of pixel intensity even within the same type of cellular components in different embryos, it is difficult to separate nuclear regions from the surrounding cytoplasmic region in differential interference contrast (DIC) microscope image. This study explores a discriminative representation of a local patch around a fixed pixel, called top-ranked intensity-ordered descriptor (TRIOD), which is prospected to distinguish the smoothed texture in the nucleus from the irregular texture in cytoplasm containing yolk granules. Then, a probability process is employed to model nuclear TRIOD prototypes, and the enhanced nuclear probability map can be constructed with the TRIODs of all pixels in a DIC microscope image. Finally, a distance-regularized level set method, which not only considers the probability change in a nearby pixel but also regularizes the contour smoothness, is applied to refine the initial localization by simply thresholding on the enhanced probability map. Experimental results show that the proposed strategy can give much better performance for segmentation of nuclear regions than the conventional strategies.