Hasil untuk "Microscopy"

P. Bindu, Sabu Thomas

ZnO nanoparticles were synthesized from chitosan and zinc chloride by a precipitation method. The synthesized ZnO nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction peak profile analysis, Scanning electron microscopy, Transmission electron microscopy and Photoluminescence. The X-ray diffraction results revealed that the sample was crystalline with a hexagonal wurtzite phase. We have investigated the crystallite development in ZnO nanoparticles by X-ray peak profile analysis. The Williamson–Hall analysis and size–strain plot were used to study the individual contributions of crystallite sizes and lattice strain ϵ on the peak broadening of ZnO nanoparticles. The parameters including strain, stress and energy density value were calculated for all the reflection peaks of X-ray diffraction corresponding to wurtzite hexagonal phase of ZnO lying in the range 20°–80° using the modified form of Williamson–Hall plots and size–strain plot. The results showed that the crystallite size estimated from Scherrer’s formula, Williamson–Hall plots and size–strain plot, and the particle size estimated from Transmission electron microscopy analysis are very much inter-correlated. Both methods, the X-ray diffraction and Transmission electron microscopy, provide less deviation between crystallite size and particle size in the present case.

D. Paganin, S. Mayo, T. Gureyev et al.

J. Stempak, R. T. Ward

A n a q u e o u s so lu t ion of u r a n y l ace t a t e was first e m p l o y e d as a n e l ec t ron s ta in by W a t s o n (1958). W e h a v e f o u n d t h a t this s ta in , a l t h o u g h f r e q u e n t l y effective, is capr ic ious . T h e s ta in m a y no t inc rease con t r a s t of a g iven spec imen , a n d m a y , in o the r ins tances , l eave u n d e s i r a b l e c o n t a m i n a t i o n on a s t a ined grid. W h i l e a n e x p e r i m e n t on d e h y d r a t i n g a g e n t s for e l ec t ron m i c r o s c o p y was in progress , u r a n y l ace t a t e was d issolved in m e t h a n o l in a n effort to a c c o m pl ish en bloc s ta in ing . I t was no t ed t h a t the u r a n y l a ce t a t e was ve ry soluble in m e t h a n o l in con t r a s t to its l im i t ed solubi l i ty in w a t e r a n d e thano l . A t the t ime of this obse rva t ion , it was felt t h a t a n inc reased c o n c e n t r a t i o n of u r a n y l ace t a t e m i g h t a id in s t a i n i ng some t issue c o m p o n e n t s or m i g h t s ta in t issue m o r e cons i s t en t ly t h a n the less c o n c e n t r a t e d a q u e o u s s tain.

Y. Martin, D. Abraham, H. K. Wickramasinghe

H. Pehamberger, Andreas Steiner, Klaus Wolff

Sabri Koraltan, Joe Sunny, Tamer Karaman et al.

Higher-order skyrmions and antiskyrmions are topologically protected spin textures with an integer topological charge other than $\pm 1$ and nucleate from topological point defects in regular Bloch walls, known as vertical Bloch lines. So far, they have only been observed using Lorentz transmission electron microscopy. In this work, we show that higher-order spin textures coexisting in Co/Ni multilayers at room temperature can be visualized by high-resolution magnetic force microscopy (MFM). The experimental results are supported by micromagnetic simulations confirming that different spin objects give rise to distinct MFM contrast in full agreement to our observations.

Ketai He, Mingjie Xu, Wen Liao et al.

Abstract Aesthetics play a crucial role in patients’ choice of orthodontic clear aligners, as poor color stability can compromise their appearance during wear. This study aimed to evaluate the color and surface stability of different types of orthodontic clear aligners exposed to various concentrations of curcumin solutions in vitro. Four types of clear aligners (Invisalign, Angelalign, Spark, and Dreve), along with non-thermoformed Dreve film, were cut into 5 mm × 5 mm squares and immersed in curcumin solutions of different concentrations and a control solution. The concentrations were determined based on the curcumin content in curry. Anhydrous ethanol was used as the solvent, which may influence surface properties and color stability and partially simulating damage caused by alcohol consumption or bacterial metabolites. After immersion for 12 h and 7 days, the squares were ultrasonically cleaned, and color changes were measured using a colorimeter, then converted to National Bureau of Standards (NBS) units. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe surface characteristics before and after staining. After 12 h of immersion in 10 µg/ml solutions, all samples except the Dreve film exhibited at least an “Appreciable: marked change,” with Angelalign showing a more pronounced color alteration. After 7 days of immersion, most materials displayed color changes ranging from “Much: extremely marked change” to “Very much: change to other colors.” Across all concentrations and time points, Invisalign aligners exhibited significantly higher ΔE* values than Dreve (P < 0.05). Although SEM and AFM results were not entirely consistent, both indicated that PU-based aligners were more susceptible to surface morphology changes than PET-G-based aligners. Enhancing the aesthetic color stability of orthodontic materials could contribute to improved clinical outcomes.

Joseph Eugene Weigold, Shankar Lal, Dima Ahmad Youssef

Malaria remains a considerable challenge to international health, especially in returning travelers from endemic regions where exposure risk may be downplayed. Prompt and accurate diagnosis is crucial, especially when conventional diagnostic techniques are insufficient. This case report presents a 59-year-old man who developed fever, rash, and myalgia after returning from the Amazon rainforest. Initial laboratory tests demonstrated leukopenia, thrombocytopenia, transaminitis, and hyperbilirubinemia. Despite these abnormal results and a clinically suspicious presentation, malaria smears were negative. Since the symptoms did not resolve, a Karius test—a plasma-based microbial cell-free DNA sequencing assay—successfully detected the presence of Plasmodium vivax, thus establishing the diagnosis. The patient needed several treatment regimens for the recurrent attacks, including chloroquine and primaquine, artemether-lumefantrine, and eventually a combination of quinine and doxycycline together with a prolonged course of primaquine. His symptoms resolved completely after the last treatment regimen, along with the normalization of the blood counts and liver function tests. This case demonstrates the limitations of smear microscopy diagnosis in <i>P. vivax</i> infections, highlights the role of molecular diagnostics like the Karius test, and stresses the importance of preventing relapses with adequate hypnozoite clearance. It further highlights the importance of clinician awareness and diligent follow-up in cases of travel-related Malaria, especially those with unusual presentations or recurrent symptoms.

Si Woo Lee, Hyunki Park, Minyoung Lee et al.

Background Sodium-glucose cotransporter type 2 (SGLT2) inhibitors, such as dapagliflozin, are primarily used to lower glucose in type 2 diabetes. Recent studies suggest broader metabolic effects, particularly in the liver. This study explores the molecular mechanisms by which dapagliflozin influences hepatic glucose and lipid metabolism, hypothesizing that it activates the 5’-adenosine monophosphate-activated protein kinase (AMPK)-sirtuin 1 (Sirt1) pathway to promote gluconeogenesis and reduce lipid accumulation via autophagy. Methods HepG2 hepatocellular carcinoma cells were treated with dapagliflozin, and Western blotting, quantitative reverse transcription polymerase chain reaction, and fluorescence microscopy were used to assess gluconeogenic enzyme expression and autophagy. In vivo, mice with liver-specific autophagy related 7 (Atg7) deletion and those on a high-fat diet were used to evaluate glucose regulation, lipid metabolism, and autophagy. Results Dapagliflozin significantly increased expression of gluconeogenic enzymes like phosphoenolpyruvate carboxykinase (PEPCK) in HepG2 cells and enhanced autophagic flux, evidenced by increased light chain 3B (LC3B)-II levels and autophagosome formation. AMPK-Sirt1 activation was confirmed as the underlying mechanism. Additionally, dapagliflozin reduced fatty acid synthesis by suppressing enzymes such as acetyl-CoA carboxylase and fatty acid synthase, while promoting fatty acid degradation via carnitine palmitoyltransferase 1α (CPT1α) upregulation. In high-fat diet mice, dapagliflozin increased hepatic gluconeogenesis and reduced lipid accumulation, though serum cholesterol and triglyceride levels were unaffected. Conclusion Dapagliflozin enhances hepatic gluconeogenesis and reduces steatosis by activating the AMPK-Sirt1 pathway and promoting autophagy. These findings suggest that SGLT2 inhibitors could offer therapeutic benefits for managing hepatic lipid disorders, beyond glycemic control.

Sourabh Sharma, Manuel Vidal, Manuel Vidal et al.

BackgroundGlutamate dysregulation leading to neuronal excitotoxicity and neuroinflammation are associated with neurological disorders, specifically autism spectrum disorders (ASD) in preterm neonates. The lack of physiologically relevant in vitro models has limited mechanistic understanding of glutamate dysregulation and neuroinflammation during pregnancy. This study evaluated the effect of environmental pollutant and flame retardant, Polybrominated Diphenyl Ethers (PBDE) 99 and 47, on cell viability, glutamate dysregulation, and neuroinflammation using a microphysiologic system (MPS) of human fetal blood-brain-barrier organ on a chip (FB-OOC).MethodsThe FB-OOC is composed of 3-cell culture chambers, connected by microchannels, containing 1) human brain microvessel endothelial cells (HBMEC), 2) human vascular pericytes (HBVP), and 3) a triculture of neurons, astrocytes, and microglia in a 5:2:1 ratio, respectively. To assess the effect of toxicants on glutamate dysregulation and neuroinflammation, control (standard media) endothelial cells were exposed to PBDE 99 and 47 (150 ng/mL). To mimic the passage of PBDE through the placenta, endothelial cells in FB-OOC were exposed to conditioned PDBE media (1:1) derived from a placenta-OOC. In parallel, triculture cells were directly treated in a 96-well plate. Dextran propagation over 72 h confirmed FB barrier function. The activation status of microglia was determined using immunocytochemistry for CD11 b and Iba1, respectively. Cell morphology (microscopy), cell cytotoxicity (Lactate Dehydrogenase and glutamate assays), and cytokines (multiplex assay) were measured.ResultsPhysiologic FB-OOCs were characterized by 1) viable cell cultures expressing standard cell morphologies and cell-specific markers, 2) barrier formation confirmed by decreased dextran propagation over 72 h, and 3) baseline glutamate and pro-inflammatory cytokine production. On-chip PBDE and placenta-derived metabolites of PBDE treatment in the endothelial chamber induced cell cytotoxicity and significant upregulation of glutamate in the triculture but did not induce neuroinflammation nor microglia activation compared to the controls. Conversely, 2D triculture experiments showed direct PBDE treatment-induced significant neuroinflammation (TNF-α, GM-CSF, IL-8) compared to PBDE placenta-derived metabolites or controls.ConclusionThis study established an FB model that recreated intercellular interactions. We report PBDE-induced glutamate dysregulation, often associated with the development of ASD, independent of neuroinflammation.

Cerboni Noemi, Stephens Kyle J., Shepelin Nick A. et al.

The production of superheavy elements requires targets capable of withstanding prolonged, high-intensity heavy ion-beam bombardment. Current methods, such as molecular plating, produce actinoid films with insufficient stability under these conditions. To address this, a thermally superior solid solution between actinoids and Pd has been synthesized using the coupled reduction process and successfully tested. To further improve said technique, we aimed at confining Tb (i.e., a surrogate for late actinoid elements) within a thin Pd layer with a thickness of a typical target layer suitable for superheavy element synthesis. The thin Pd film was initially deposited onto a support composed of a Ni backing foil and a TiN layer intended to block the diffusion of Tb and Pd into the underlying Ni during coupled reduction. The thermal stability of the obtained multilayered samples and the diffusion behavior of Tb were studied by cross-sectional analysis via scanning electron microscopy coupled with focused ion beam milling and energy dispersive X-ray spectroscopy.

B. Rothenhäusler, W. Knoll

U. Dürig, D. Pohl, F. Rohner

D. Rugar, H. J. Mamin, P. Guethner

Divyansh Wadhwa, Gurharinder Singh, Krishna Bharadwaj Balasubramanian

This study examines the behavior and tunability of plasmonic lenses created from arrays of nanoslits, applicable in sub-wavelength optical microscopy and other high-resolution imaging systems. We performed simulations on COMSOL Multiphysics to assess power flow and focal shifts in plasmonic lenses with differing slit designs, refractive indices, and angular distributions. The findings indicate that the confinement can be regulated by adjusting these parameters.

Gaole Dai, Cheng-Ching Tseng, Qingpo Wuwu et al.

The rapid pace of innovation in biological microscopy imaging has led to large images, putting pressure on data storage and impeding efficient sharing, management, and visualization. This necessitates the development of efficient compression solutions. Traditional CODEC methods struggle to adapt to the diverse bioimaging data and often suffer from sub-optimal compression. In this study, we propose an adaptive compression workflow based on Implicit Neural Representation (INR). This approach permits application-specific compression objectives, capable of compressing images of any shape and arbitrary pixel-wise decompression. We demonstrated on a wide range of microscopy images from real applications that our workflow not only achieved high, controllable compression ratios (e.g., 512x) but also preserved detailed information critical for downstream analysis.

I. Karatasios, S. Papaioannou, E. Tziviloglou et al.

The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness.The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.

Sudarningsih Sudarningsih, Fahruddin Fahruddin, Tetti Novalina Manik et al.

We have conducted research to identify the morphology of magnetic minerals from the land in the Banjarmasin regional settlement area. We used scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM EDS) on the soil sample to look at the shape of its magnetic minerals. In nature, magnetic minerals can indicate the presence of heavy metals. The shape of a magnetic mineral can reveal its origin in either the litogenic or anthropogenic processes. There were mostly pseudo-single domain grains (3.29–10 m) and multidomain grains (> 10–134.69 m) in the study area. The multidomain grains came in the shapes of sperules, irregulars, angles, and prisms. These results indicate that in the residential land location there are magnetic mineral grains originating from litogenic and anthropogenic processes.

Christiano Bruneli Peres, Leandro Cardoso de Morais, Pedro Miguel Rebelo Resende

The alarming increase in the concentration of carbon dioxide (CO2) in the atmosphere, mainly due to human emissions, represents a significant threat to life. In this context, carbon capture and storage (CCS) technologies have emerged as promising solutions, such as adsorption on carbonaceous materials, standing out as a prominent approach. This study aims to quantify the maximum CO2 capture in the laboratory scale using functionalized activated carbon by passion fruit peel biomass (FACPFP) and to develop a simple and improved machine learning model to predict the capture of this greenhouse gas. FACPFP was successfully prepared through chemical activation with K2C2O4 and doping with ethylenediamine (EDA) at 700 °C and 1 h. The samples were thoroughly characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) with energy dispersive X-ray detector (EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). CO2 sorption was assessed using functional density theory (DFT). For predictive model, multiple linear regression with cross-validation was used. Under CO2 atmosphere conditions, the textural parameters allowed to see the probable presence of ultra-micropores, the BET surface area, the total pore and micropore volume were 105 m²/g, 0.03 cm³ /g and 0.06 cm³ /g, respectively. The maximum CO2 adsorption capacity in the FACPFP reached about 2.2 mmol/g at 0 °C and 1 bar. The predictive model demonstrated an improvement of CO2 adsorption precision, raising it from 53% to 61% with cross-validation. This study also aims to stimulate future investigations in the area of CO2 capture, due to the extreme relevance of this topic.

D. Rugar, H. J. Mamin, P. Guethner et al.