Field Microscopy Research Articles

Optimization of Tyrosine Kinase Inhibitor-Loaded Gold Nanoparticles for Stimuli-Triggered Antileukemic Drug Release.

Tyrosine kinase inhibitor (TKI) therapy is gaining attraction in advanced cancer therapeutics due to the ubiquity of kinases in cell survival and differentiation. Great progress was made in the past years in identifying tyrosine kinases that can function as valuable molecular targets and for the entrapment of their corresponding inhibitors in delivery compounds for triggered release. Herein we present a class of drug-delivery nanocompounds based on TKI Midostaurin-loaded gold nanoparticles that have the potential to be used as theranostic agents for the targeting of the FMS-like tyrosine kinase 3 (FLT3) in acute myeloid leukemia. We optimized the nanocompounds' formulation with loading efficiency in the 84-94% range and studied the drug release behavior in the presence of stimuli-responsive polymers. The therapeutic activity of MDS-loaded particles, superior to that of the free drug, was confirmed with toxicities depending on specific dosage ranges. No effect was observed on FLT3-negative cells or for the unloaded particles. Beyond druggability, we can track this type of nanocarrier inside biological structures as demonstrated via dark field microscopy. These properties might contribute to the facilitation of personalized drug dosage administration, critical for attaining a maximal therapeutic effect.

Role of Simulations and Experiments in Analytical Field Ion Microscopy.

Role of Simulations and Experiments in Analytical Field Ion Microscopy.

Medical treatment of eosinophilic esophagitis.

Medical treatment of eosinophilic esophagitis.

Image quality enhancement of 4D light field microscopy via reference impge propagation-based one-shot learning

Four-dimensional (4D) light-field (LF) microscopes can acquire 3D information about target objects using a microlens array (MLA). However, the resolution and quality of sub-images in the LF images are reduced because of the spatial multiplexing of rays by the element lenses of the MLA. To overcome these limitations, this study proposes an LF one-shot learning technique that can convert LF sub-images into high-quality images similar to the 2D images of conventional optical microscopes obtained without any external training datasets for image enhancement. The proposed convolutional neural network model was trained using only one training dataset comprising a high-resolution reference image captured without an MLA as the ground truth. Further, its input was the central view of the LF image. After LF one-shot learning, the trained model should be able to convert well the other LF sub-images of various directional views that were not used in the main training process. Therefore, novel learning techniques were designed for LF one-shot learning. These novel techniques include an autoencoder-based model initialization method, a feature map-based learning algorithm to prevent the overfitting of the model, and cut loss to prevent saturation. The experimental results verified that the proposed technique effectively enhances the LF image quality and resolution using a reference image. Moreover, this method enhances the resolution by up to 13 times, decreases the noise amplification effect, and restores the lost details of microscopic objects. The proposed technique is stable and yields superior experimental results compared with those of the existing resolution-enhancing methods.

One-pot platform for the collection and detection of nanoparticles: Flexible surface-enhanced Raman scattering (SERS) substrates with nano-pore structure

The potential of using flexible surface-enhanced Raman scattering (SERS) for single polymer nanoparticle detection has been recognized, however, most studies have used SERS substrates consisting of metal nanoparticles (MNPs) on hard materials, which have limited volume analysis and can easily be damaged. To overcome these issues, researchers have conducted recent studies on flexible or 3D-structured SERS substrates. This study used polydimethylsiloxane (PDMS) membranes for flexible substrates, Ag nanowires (AgNWs) to form nano-pores, and PDMS-polyethylene glycol (PEG) block copolymer (BCP) to improve solvent application. The SERS substrates were able to detect rhodamine 6G (R6G) probes with a limit of detection (LOD) of 7.06 × 10−11 M, and were mechanically stable under various conditions such as bending, stretching, and torsion. The nano-pores of the SERS substrates could separate polystyrene (PS) particles from the solution, and filtered particles were visually distinguishable from AgNWs using a dark field microscope. The flexibility of the SERS substrates also allows for swab sampling of irregular surfaces. We were able to detect up to 10–10 M of crystal violet (CV) in the contaminated scallops and collect and detect PS in stainless-steel structures covered with 200 nm PS particles. Overall, the study shows the potential of using flexible SERS substrates for single polymer nanoparticle detection in various fields.

Staphylococcus aureus Biofilm Destabilization by Tween-80 and Lung Surfactants to Overcome Biofilm-Imposed Drug Resistance.

This study is aimed to evaluating the potential of tween-80 and artificial lung surfactant (ALS) to destabilize S. aureus biofilm. The biofilm destabilization was studied by crystal violet staining, bright field microscopy, and scanning electron microscopy (SEM). During the study, S. aureus biofilm was exposed with tween-80 along various concentrations (1%, 0.1%, and 0.05%) or LS (lung surfactant) at (2.5%, 5%, and 15%) for 2 hrs. It was observed that 0.1% of tween-80 destabilized 63.83 ± 4.35% and 15% ALS 77 ± 1.7% biofilm in comparison to without treatment. The combination of tween-80 and ALS was used and showed a synergistic effect to destabilize 83.4 ± 1.46% biofilm. These results showed the potential of tween-80 and ALS as biofilm disruptors, which further needs to explore in an in-vivo animal model to access the actual potential of biofilm disruption in natural conditions. This study could play a pivotal role to overcome the problem of antibiotic resistance imposed due to biofilm formation to combat antibiotic resistance imposed by bacteria.

Isotropic micromagnetic field model of ferromagnetic stress effects

We model magnetoelastic transducer processes including virgin field DH∼, virgin prestress DσH∼ and post stress DHσ∼ using the isotropic micromagnetic field model of ferromagnetic hysteresis and magnetostriction up to the coercive field. Magnetostriction of Fe94Ni3Cr2Mo1 steel has been precisely measured for DσH∼ with a thermally isolated yoke in order to compute microscopic Brown and macroscopic Villari stress fields. Magnetization M and field H were quasistatically measured with a Hall probe and differential Faraday induction coil. Prestress DσH reveals Brown field advanced virgin susceptibility and Villari field induced stress asymmetry. Post stress DHσ∼ reveals symmetric Brown field, stress asymmetry due to negative domain walls and cyclic creep due to Villari stress sensitivity dM/dσ, hyperbolic domain coupling and Néel viscosity.

On the yield criterion of porous materials by the homogenization approach and Steigmann–Ogden surface model

In this work, we investigate the yield criterion of nanoporous materials by using homogenization approach and Steigmann–Ogden surface model. The representative volume element is proposed as an infinite matrix containing a tiny nanovoid. The matrix is incompressible, rigid-perfectly plastic, von Mises materials and nanovoids are dilute and equal in size. First, the constitutive of microscopic stress and microscopic strain rate is established based on the flow criterion. Secondly, according to the Hill’s lemma, the relationship between the macroscopic equivalent modulus and the microscopic equivalent modulus is established by homogenization approach. Thirdly, the macroscopic equivalent modulus containing the Steigmann–Ogden surface model including surface parameters, porosity and nanovoid radius is derived from the trial microscopic velocity field. Finally, an implicit macroscopic yield criterion for nanoporous materials is developed. For surface modulus, nanovoids radius and porosity studies are developed through extensive numerical experiments. The research results in this paper have reference significance for the design and manufacture of nanoporous materials.

Study on a Novel Peeling of Nano-Particle (PNP) Process for Localized Material Removal on a 4H-SiC Surface by Controllable Magnetic Field

This study proposes a novel process called peeling of nano-particle (PNP) to remove material locally on a hard material surface, such as silicon carbide (SiC), diamond, and gallium nitride (GaN), using the magnetic nano-particles in an aqueous solution controlled by magnetic fields. By the concept of the PNP process, magnetic fields are generated by two solenoid coils, which are sandwiched between the hard material sample, to pull the magnetic nano-particles to adhere to and then peel the material from the sample surface. In this experiment, iron (II, III) oxide (Fe3O4) particles with a diameter size in the range of 50–100 nm were dispersed in water, and the pH value was adjusted to 10 by potassium hydroxide (KOH). The particles were magnetically controlled on the silicon carbide (4H-SiC) surface by the magnetic fields at approximately 17 mT. To confirm the contact phenomenon of the Fe3O4 particles on the 4H-SiC surface during the PNP process, an optical system was developed by applying evanescent field microscopy to limit the observation range to approximately 300 nm from the 4H-SiC surface. According to the experimental observed results, the control phenomenon of two examples of Fe3O4 particles could be observed through their scattering light, which relates to the magnetic field generating sequence wherein the particles were magnetically pulled in and out of the 4H-SiC surface in the limit range of the evanescent field. During the particle pull to the surface, particles were able to be tracked in the X–Y directions during the approach to the 4H-SiC surface. The Brownian motion ranges in all directions of the particles decreased when the particles approached close to the surface due to the pulling magnetic field. Moreover, the magnetic field enforced the magnetic moment of the particle and limited their rotation.

Preparation, characterization, and thermal decomposition kinetics of high test peroxide gel

High test peroxide gel was prepared by low temperature freezing under the action of calcium ion compound with sodium alginate as a gelling agent. The High test peroxide gel was characterized by ultra depth of field microscope, Fourier infrared spectrometer, rheometer, synchronous thermal analyzer, and electron microscope scanner. The thermal decomposition behavior and reaction kinetics of the gel were investigated. The effective content of H2O2 in the gel before and after aging was also analyzed by KMnO4 titration. The results show that the content of sodium alginate and the concentration of calcium ion compound directly affect the gelling and rheological properties of high test peroxide gel, and the gel with low sodium alginate content had a more uniform tissue structure. The Eα and lg(A/s−1) of the high test peroxide gel decomposition reaction are 69.10 kJ mol−1 and 9.13, respectively. Na2O, CaO, CaCl2 and CaSO4 are the main components of the high test peroxide gel thermal decomposition condensate products. After ignition, a boron-based high test peroxide gel propellant can produce a steady combustion. After being stored at 263 K for 20 days, the effective content of H2O2 in the gel is 96.50%, and the decomposition rate is only 0.63%.

Direct observation of removal of SiO2 nano-particles from silica surfaces: an evanescent field microscopy study and shear flow acting moment

It has been difficult to detach smaller abrasive nano-particles from polished surfaces. In this article, we observed the behaviors of Ø50, 70, and 300 nm SiO2 particles on a silica surface in an inevitable liquid nano-scale shear flow field as a rinse cleaning by using an evanescent light. These results implied that larger-sized particles were detached because the quantitative moment in the shear flow acting on the particle is considerably higher than those of the sub-100 nm particles. The acting moment would be able to describe the detachability of the nano-particles on the surface.

Influence of white blood cells count on parasite density in Malaria in children aged 6 to 59 months in Benin

For many years, the treatment of malaria was based on clinical presumptive diagnosis, making its differential diagnosis with other causes of hyperthermia difficult. This drug pressure has led to the emergence of Plasmodium strains resistant to the most commonly used antimalarial drugs. This is why in 2004, the health authorities decided to revise the policy of malaria management by adopting a new strategy based on the rational use of artemisininbased combination therapies after the biological confirmation of suspected malaria cases. The biological diagnosis is an essential part of malaria management. The gold standard technique for diagnosis is the thick drop combined with the calculation of parasite density (PD), which is determined on the basis of the number of parasites counted in a microscopic field against a proposed standard number of leukocytes. The number of leukocytes used to calculate the parasite density should ideally be the actual number of leukocytes in the patient per cubic millimetre of blood. However, in the absence of the availability of a blood count at the time of the thick drop, an average number of 8 000 leukocytes/mm3 was used by the World Health Organisation (WHO) to estimate the parasite density. Nonetheless, in Benin the average number of leukocytes adopted by the National Malaria Control Programme (PNLP) is 6 000/mm3. The aim of our study was to determine the impact of the leukocyte count on the calculation of the parasite density in cases of uncomplicated malaria. The study was a cross-sectional study with an analytical aim and took place in 2 hospitals in Benin, the Klouékanmey zone hospital in the south of Benin and the Djougou health centre in the north. It involved a population of 476 children aged between 6 and 59 months who were seen in consultation and in whom the clinical diagnosis of simple Plasmodium falciparum malaria was suspected. Children aged between 6 and 59 months, weighing at least 5 kg, with an axillary temperature ≥ 37.5°C at the time of consultation or a history of fever in the last 24 hours or other symptoms pointing to the diagnosis of malaria were included. Infestation was mono-specific for Plasmodium falciparum. Informed consent was required from the child's parents or guardian. The criteria for non-inclusion in our study were the presence of at least one sign of malaria severity, signs of severe malnutrition or a febrile state related to underlying infectious diseases other than malaria. Thick blood count and haemogram were systematically performed in all included children. Parasite density was calculated according to 3 methods, first using a weighted leukocyte count of 6 000/mm3 recommended by the Benin National Malaria Control Programme (PNLP), then a leukocyte count of 8 000/mm3 recommended by the World Health Organisation and finally the patient's actual leukocyte count obtained from the blood count. It should be noted that these different samples were respectively taken on the day of inclusion in compliance with the conditions of the pre-analytical phase in force in our medical biology laboratory. At the end of our study, 313 children, i.e. 65.76% of our study population had a positive white blood cell count with a positivity rate of 62.14% in Djougou, i.e. 174 children, and 70.9% in Klouékanmey, i.e. 139 children. The average leukocyte count in these children was 11,580/mm3. Among them, 205 children had an abnormal white blood cell count, i.e. 17 cases of leukopenia (5.43%) and 188 cases of hyperleukocytosis (60.06%). Using successively the average number of 6 000 leukocytes/mm3 proposed by the Benin PNLP and that of 8 000 leukocytes/mm3 proposed by the WHO, the average parasite densities were respectively 47,943 and 63,936 trophozoïtes/µl against 92,290 trophozoïtes/µl when the real number of leukocytes of the patients was used for the calculation of the PD. By using an average of 6 000 leukocytes/mm3 for PD calculation, 60% of the calculated PDs were underestimated and 6% were overestimated. Using an average of 8 000 leukocytes/mm3 resulted in 49% of PD being underestimated and 15% being overestimated. The difference between the three calculation methods was considered statistically significant (p value <0.05). The use of 6 000 or 8 000 coefficients for the estimation of parasitaemia could lead to a significant underestimation of the parasite load.

Acquisition of field ion microscope image using deflector during atom probe analysis

Atom probe (AP) is an elemental analysis technique that ionizes surface atoms by a strong field formed by a sharp needle-shaped sample and identifies ions in an atom-by-atom manner by the time of flight mass spectrometer. The detection efficiency of AP has been estimated to be extremely high by the correlation to field ion microscopy (FIM) observations, which show the surface morphology change in atomic scale during the field evaporation of the surface layer. The estimation of detection efficiency has been indirectly done by the comparison of AP data and FIM observation. We evaluated the detection efficiency of AP directly from ion data and counting spot change in FIM images by repeating two measurements sequentially in this work. The experimentally obtained ratio between the detected count over disappeared spots was 10/33 ≈ 0.30, which was ca. 1/2 of the optimal value expected from the opening area ratio of the microchannel plate (∼0.60).

Single capture bright field and off-axis digital holographic microscopy: publisher's note.

This publisher's note contains corrections to Opt. Lett.48, 876 (2023)10.1364/OL.478674.

Lyophilized biopolymeric beads of chitosan-xanthan with edible fungus Laccaria laccata (Scop.) Cooke as forest ectomycorrhizal biofertilizers

Objective: To evaluate whether or not the spores of the edible fungus Laccaria laccata (Scop.) Cooke encapsulated in a lyophilized biopolymeric matrix of chitosan-xanthan can cause ectomycorrhization in Pinus greggii Englem. trees under greenhouse conditions. Methodology: Spores of the edible ectomycorrhizal fungus L. laccata were encapsulated in beads made with the chitosan-xanthan biopolymer. The embedded spores were analyzed using scanning electron microscopy to evaluate possible structural damage. Next, these beads were used as biofertilizers in a greenhouse bioassay using Pinus greggii plants to evaluate their ability to be ectomycorrhized. The bioassay lasted 270 days. Subsequently, stereoscopic and bright field microscopy was used to determine if the roots of the pines had been subjected to an ectomycorrhizal colonization. Additionally, the growth of inoculated plants was evaluated compared to non-inoculated plants, 180 and 270 days after sowing. Results: The spores of L. laccata encapsulated in the biopolymeric matrix formed ectomycorrhizae in the roots of P. greggii. The percentages of ectomycorrhizal colonization in the plants ranged from 80 to 90%, demonstrating that the production of chitosan-xanthan biopolymeric beads can maintain the viability of the spores of the ectomycorrhizal fungus evaluated and extensively colonize the roots of Pinus greggii. Study Limitations/Implications: The biopolymeric matrix beads that contain spores of the fungus L. laccata can induce ectomycorrhization in trees of forest importance. Conclusions: The spores of an edible ectomycorrhizal fungus encapsulated in the chitosan-xanthan biopolymer have potential as a forest biofertilizer, which opens the opportunity to scale its use up to an industrial level.

Effects of WC mass fraction on microstructure and tribological behavior of plasma sprayed FeMnCoCr–WC coatings

FeMnCoCr–WC coatings with WC mass fractions of 0 %, 5 % and 10 % were prepared on Ti6Al4V alloy by plasma spraying to improve the tribological properties of FeMnCoCr coating. The effects of WC mass fraction on the microstructure, chemical elements and phases of obtained coatings were analyzed via a scanning electron microscope, super–depth of field microscope, energy dispersive spectrometer and X–ray diffraction, respectively, and the wear behavior of FeMnCoCr–WC coatings at room temperature and 500 °C was also evaluated using a ball–on–disc wear tester. The results show that the WC addition improves the coating hardness through the grain refinement, and the coefficients of friction (COFs) and wear rates of coatings are decreased with the increase in WC mass fraction at room temperature and 500 °C. The wear rates of FeMnCoCr–WC coatings at 500 °C are increased compared with those at room temperature, which are attributed to the softening effect and plastic deformation at high temperature. The wear mechanism of FeMnCoCr–WC coatings at RT is changed from adhesive wear + oxidative wear + abrasive wear to abrasive wear + delamination wear + oxidative wear as the WC mass fraction increases; while those of at 500 °C are not changed with the increase in WC mass fraction.

Computer Vision Identifies Recurrent and Nonrecurrent Ductal Carcinoma in Situ Lesions with Special Emphasis on African-American Women

Although nonrecurrent and recurrent forms of ductal carcinoma in situ (DCIS) of the breast are observed, no evidence-based test can make this distinction. The current retrospective case-control study used archival DCIS samples stained with anti-phospho-Ser226-glucose transporter type 1 and anti-phosphofructokinase type L antibodies. Immunofluorescence micrographs were used to create machine learning models of recurrent and nonrecurrent biomarker patterns, which were evaluated in cross-validation studies. Clinical performance was assessed by holdout studies using patients whose data were not used in training. Micrographs were stratified according to the recurrence probability of each image. Recurrent patients were defined by at least one image with a probability of recurrence ≥98%, whereas nonrecurrent patients had none. These studies found no false-negatives, identified true-positives, and uniquely identified true-negatives. Roughly 20% of the microscope fields of recurrent lesions were computationally recurrent. Strong prognostic results were obtained for both white and African-American women. This machine tool provides the first means to accurately predict recurrent and nonrecurrent patient outcomes. Data indicate that at least some false-positive findings were true-positive findings that benefited from surgical intervention. The intracellular locations of phospho-Ser226-glucose transporter type 1 and phosphofructokinase type L likely participate in cancer recurrences by accelerating glucose flux, a key feature of the Warburg effect.

Isolation and molecular characterization of pathogenic Leptospira species from cattle in Zaria and its environs, Kaduna State, Nigeria

Leptospirosis is a zoonotic disease caused by pathogenic serovars of Leptospira spp. The paucity of information on the status of leptospirosis in cattle in the study area led to this study. A cross-sectional study was carried out with a total of 130 kidney samples from cattle which were cultured using Ellinghausen Mc-Cullough Johnson Harris enrichment and examined on dark field microscope after 8 weeks of culture. DNA was extracted directly from 6 kidney tissues to confirm the presence of pathogenic Leptospira spp. and further sequenced to determine the species of Leptospira spp. Result of the culture indicated that the overall occurrence of Leptospira spp.was 32.30 %. Phylogenetic analysis of lipL32 sequences showed Leptospira interrogans isolates from cattle nucleotide homology ranging from 99.40 % to 99.73 % with a query cover of 100 % when compared with sequence from gene bank. In conclusion, this study established that cattle may act as a significant reservoir of leptospirosis in the study area and pose a potential risk to abattoir workers, veterinarians and local communities.

Accurate computation of chemical contrast in field ion microscopy

We present a computational approach to simulate local contrast observed in field ion microscopy (FIM). It is based on density-functional theory utilizing the Tersoff-Hamann approach as done in scanning tunneling microscopy (STM). A key requirement is the highly accurate computation of the surface states' wave-function tails. To refine the Kohn-Sham states from standard iterative global solvers we introduce and discuss the EXtrapolation of Tails via Reverse integration Algorithm (EXTRA). The decaying tails are obtained by reverse integration (from outside in) using a Numerov-like algorithm. The starting conditions are then iteratively adapted to match the values of plane-wave Kohn-Sham wave functions close to the surface. We demonstrate the performance of the proposed algorithm by analyzing and showing the chemical contrast for Ta, W, and Re at Ni surface.

Application of Nanosecond Pulsed Electric Field and Autofluorescence Lifetime Microscopy of FAD in Lung Cells.

Exposure of nanosecond pulsed electric fields (nsPEFs) to live cells is an increasing research interest in biology and medicine. Despite extensive studies, a question still remains as to how effects of application of nsPEF on intracellular functions are different between cancerous cells and normal cells and how the difference can be detected. Herein, we have presented an approach of autofluorescence lifetime (AFL) microscopy of flavin adenine dinucleotide (FAD) to detect effects of application of nsPEF having 50 ns of a pulse width, nsPEF(50), on intracellular function in lung cancerous cells, A549 and H661, which show nsPEF(50)-induced apoptosis, and normal cells, MRC-5, in which the field effect is less or not induced. Then, the application of nsPEF(50) is shown to increase the lifetime of FAD autofluorescence in lung cancerous cells, whereas the electric field effects on the autofluorescence of FAD was not significant in normal healthy cells, which indicates that the lifetime measurements of FAD autofluorescence are applicable to detect the field-induced change in intracellular functions. Lifetime and intensity microscopic images of FAD autofluorescence in these lung cells were also acquired after exposure to the apoptosis-inducer staurosporine (STS). Then, it was found that the AFL of FAD became longer after exposure not only in the cancerous cells but also in the normal cells. These results indicate that nsPEF(50) applied to lung cells induced apoptotic cell death only in lung cancerous cells (H661 and A549) but not in lung normal cells (MRC-5), whereas STS induced apoptotic cell death both in lung cancerous cells and in lung normal cells. The lifetime microscopy of FAD autofluorescence is suggested to be very useful as a sensitive detection method of nsPEF-induced apoptotic cell death.