Scanning Atomic Force Microscopy Research Articles

In-depth opto-electrical analysis of Ni:CdS film towards the performance as Ag/Ni:CdS/FTO Schottky diode

Nickel doped cadmium sulfide (Ni:CdS) thin films are deposited onto glass and FTO substrate using spray pyrolysis technique. The effect of annealing temperature on the thin films and its morphological, microstructural, optical dispersion, linear-nonlinear and electrical, properties are extensively investigated by using various techniques such as field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM), X-ray diffraction (XRD) and ultraviolet visible (UV-VIS) diffuse reflectance spectroscopy. Morphological studies revealed that doped thin films surface is almost homogeneous and well-covered. Peaks associated with Ni, Cd and S elements are present in EDS analysis, which confirm the composition of the films. The energy band calculation using the Tauc plot from the recorded absorption spectra reveals the decrement in the energy gap from 3.75 eV to 3.61 eV and the refractive index is in the range of 2.57–2.62. The effect of annealing temperature on complex dielectric constant are also analyzed. Moreover, the dispersion of refractive index is calculated in terms of Wemple-DiDomenico approach. Third order susceptibility and nonlinear refractive index are calculated of Ni:CdS films. The designed Ag/Ni:CdS/FTO Schottky diode is tested under illumination conditions, and the empirical diode parameters, viz. ideality factor, barrier height, series resistance etc. are influenced by annealing temperature.

Fabrication of carbon nanotube/ titanium dioxide nanomaterials-based hydrogen sensor using novel two-stage dielectrophoresis process

The porosity and large surface area of carbon nanotubes (CNTs) made them a candidate active material for gas sensing applications. However, the responsivity and sensitivity of CNTs toward hydrogen are lower than those of metal oxide semiconductor materials such as TiO2. The addition of TiO2 to CNTs is found to increase the sensitivity of the resulting composite material at the expense of increasing the resistance. This paper presents a new dielectrophoresis (DEP) process to fabricate nanoparticle-based hydrogen sensors at room temperature. The simple and low-cost process is based on tuning the AC signal frequency to deposit different nanoparticles in stages, forming a composite sensing layer across interdigitated electrodes (IDE). The sensing layers have been characterized using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and atomic force microscopy (AFM). Sensors fabricated with only CNTs showed low resistance and weak sensitivity of less than 2%. The sensitivity has increased to 3.42% when CNTs are deposited together with TiO2 in a single stage. However, the sensor shows high resistance because TiO2 particles interrupt the conduction paths of CNTs. A high sensitivity of 15.78% and a low resistance of ∼524 Ω have been achieved when CNTs are deposited individually in the first stage, and followed by depositing the TiO2 in the second stage. This work provides a proof-of-concept that the two-stage DEP enhances the performance of the sensor in terms of sensitivity and resistance compared to single-stage DEP, which is highly desirable in fabricating composite and multi-layer sensing materials.

Insights into Interfacial Features of Metal/Eco-Composites Designed for Energy Storage

The development of innovative materials with improved properties is required for the field of energy storage. This article proves that it is possible to utilize bio-derived fillers to tune the performance of biodegradable polymers. For this scope, eco-composites were attained by loading several amounts of walnut leaf powder (WLP) in hydroxyethylcellulose (HEC). Basic testing was conducted to emphasize the sample’s suitability for the pursued application. The rheological behavior was altered with the addition of WLP at low shear rates, which became more pseudoplastic, resulting in composite films with higher thickness uniformity. Wettability characteristics were used to analyze the macro-level adhesion of the platinum-containing samples, and the results showed that the presence of WLP led to the augmentation of interfacial compatibilization of the composite with the metal layer. The electron microscopy and atomic force microscopy scans showed the proper distribution of the WLP in the matrix. Local adhesion data derived from DFL-height curves further showed that the inclusion of WLP improves the adhesion capabilities at the nanoscale. The dielectric spectroscopy tests proved that the used biofiller leads to an enhancement in the permittivity of the composite with respect to the neat HEC. By accounting for all results, the generated eco-composites are suggested as alternative dielectrics for usage in the energy storage domain.

Investigations on the effect of 2-[(furan-3ylmethylene)-amino]-benzenethiol on corrosion in carbon steel

A Schiff base namely, 2-[(furan-3ylmethylene)-amino]-benzenethiol (2-FAB) was synthesized and its influence on the inhibition of corrosion in carbon steel immersed in 0.5 M H2SO4 was investigated by weight loss analysis, potentiodynamic polarization studies, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and FT-IR spectroscopy. The weight loss measurements showed that 2-FAB has an excellent inhibiting efficiency of 95.51% at a concentration of 250 ppm. The inhibitor efficiency was found to depend on both the concentration and molecular structure of the inhibitor. Potentiodynamic polarization curves revealed that the studied inhibitors represent a mixed-type, predominantly cathodic control. An equivalent circuit is suggested based on an analysis of EIS data. Surface analysis using scanning electron microscope (SEM) and atomic force microscopy (AFM) show a significant morphological improvement on the mild steel surface with the addition of 2-FAB. The negative value of standard free energy of adsorption in the presence of inhibitor suggests the spontaneous adsorption of inhibitors on the carbon steel surface. The Temkin and Langmuir adsorption isotherms were found to provide a accurate description of the adsorption behavior of the inhibitor. Taken as a whole, this work demonstrates that 2-FAB shows promising results in resisting the deterioration of carbon steel in 0.5 M H2SO4 environment. The inhibitor forms a protective film on the surface of the carbon steel, significantly reducing its corrosion rate.

The green synthesis of nanoparticles using Costus pictus leaf extract blended with paint and its potential applications

Nanoparticles are important due to their unique properties that may lead to new and exciting applications. Green synthesis has many advantages amongst physical and chemical methods of nanoparticle synthesis since the method is simple, inexpensive, and environmentally friendly. This research work describes the synthesis of carbon nanoparticles using leaf extract of Costus pictus and the characterization studies were carried out by Fourier Transform Infra-Red and Ultra Violet-Visible spectrophotometry. Incorporation of the nanoparticles of Costus pictus leaf extract into the paint formulation increases the corrosion protection properties. The inhibitive effects were investigated using weight loss, polarization, and impedance studies. The surface analysis techniques of Scanning Electron Microscope and Atomic Force Microscopy were used to investigate the morphology study. Findings show that synthetic nanoparticles mixed with paint function as more effective and thermally stable agents, serving as an alternative environmentally acceptable anticorrosion addition for cleaning and pickling processes in industries.

A Next-Generation qPlus-Sensor-Based AFM Setup: Resolving Archaeal S-Layer Protein Structures in Air and Liquid.

Surface-layer (S-layer) proteins form the outermost envelope in many bacteria and most archaea and arrange in two-dimensional quasicrystalline structures via self-assembly. We investigated S-layer proteins extracted from the archaeon Pyrobaculum aerophilium with a qPlus sensor-based atomic force microscope (AFM) in both liquid and ambient conditions and compared it to transmission electron microscopy (TEM) images under vacuum conditions. For AFM scanning, a next-generation liquid cell and a new protocol for creating long and sharp sapphire tips was introduced. Initial AFM images showed only layers of residual detergent molecules (sodium dodecyl sulfate, SDS), which are used to isolate the S-layer proteins from the cells. SDS was not visible in the TEM images, requiring more thorough sample preparation for AFM measurements. These improvements allowed us to resolve the crystallike structure of the S-layer samples with frequency-modulation AFM in both air and liquid.

Design and Study of Nanoceria Modified by 5-Fluorouracil for Gel and Polymer Dermal Film Preparation.

In this work we studied nanoceria (CeO2NPs) and nanoceria modified by 5-fluorouracil (5FU) as potential APIs. Nanoceria were synthesized by precipitation in a matrix of hydroxyethyl cellulose or hydroxypropylmethyl cellulose, using cerium (III) nitrate and meglumine. Nanoceria properties were estimated by UV, FTIR and X-ray photoelectron spectra; scanning electron and atomic force microscopy; powder X-ray diffraction patterns and energy dispersive X-ray microanalysis. The cytotoxicity of nanoceria and polymer-protected nanoparticles was evaluated using the established cell line NCTC clone 929 (C3H/An mouse, subcutaneous connective tissue, clone of L. line). The morphology and metabolic activity of nanoparticles at 10 μg∙mL-1 of cells was not significant. In addition, the cytotoxic effects of nanoceria were assessed on two human colorectal cancer cell lines (HT29 and HCT116), murine melanoma B16 cells and normal human skin fibroblasts. An inhibitory effect was shown for HCT116 human colorectal cancer cells. The IC50 values for pure CeO2NPs and CeO2NPs-5FU were 219.0 ± 45.6 μg∙mL-1 and 89.2 ± 14.0 μg∙mL-1, respectively. On the other hand, the IC50 of 5FU in the combination of CeO2NPs-5FU was 2-fold higher than that of pure 5FU, amounting to 5.0 nmol∙mL-1. New compositions of nanoceria modified by 5-fluorouracil in a polymer matrix were designed as a dermal polymer film and gel. The permeability of the components was studied using a Franz cell.

Covalent modification of (+)-catechin to improve the physicochemical, rheological, and oxidative stability properties of rice bran protein emulsion

The aim of this study is the effects of (+)-catechin (CC) covalent cross-linking (CCCI) (0.05–0.25 %, w/v) on the physicochemical properties, rheological properties, and oxidative stability of rice bran protein (RBP) emulsion. Analysis of particle size, ζ-potential, circular dichroism, fluorescence spectroscopy, surface hydrophobicity, and emulsifying properties demonstrated that a concentration of 0.15 % (w/v) CCCI facilitated protein structure unfolding, resulting in reduced particle size, enhanced electrostatic repulsion, and improved emulsion stability. Moreover, the covalent complexes of RBP-0.15 %CC (w/v) exhibited increased viscosity and shear stress, reflected by the highest G′ and G″ values, ultimately enhancing the oxidative stability. Furthermore, analysis using atomic force microscopy and confocal laser scanning microscopy revealed that the RBP-0.15 %CC complexes exhibited the smallest particle size (164 nm) and displayed greater homogeneity. An increase in CC concentration to 0.25 % (w/v) resulted in a higher emulsion aggregation. The emulsions stabilized by CCCI exhibited superior rheological properties and enhanced oxidation stability compared to the control. In conclusion, an appropriate amount of CC can enhance the rheology and oxidation stability of the RBP emulsion, while CCCI treatment holds potential for expanding the utility of RBP in various applications.

Preparation of xerogel based on syndiotactic polystyrene (sPS)/MWCNTs hybrid polymer gel for application as a dielectric material with high dielectric permittivity

MWCNTs were dispersed in sPS gel in both pristine as well as functionalized form to observe its effect on structure, morphology, thermal as well as dielectric properties of the resulting hybrid polymer gel. Since, the ortho-xylene induces clathration in pure sPS polymer in α-phase leading to thermoreversible gelation resulting in the δ-crystalline phase (sPS gel). Therefore, the removal of solvent from solvated δ-crystalline phase gives non-solvated δe-crystalline phase (sPS xerogel). The three dimensional fibrillar networks, as observed with scanning electron microscopy (SEM) and atomic force microscopy (AFM), have the polymer chains with s(2/1)2 helical conformation which makes the gel elastic. Fourier transform infra red spectroscopy (FTIR) shows the conformation change from trans planar to s(2/1)2 helical as indicated by the disappearance of peak at 541 cm−1 and appearance of peak at 537 cm−1 and 571 cm−1. The peak at 7.9° confirms the δ-crystalline phase presence whereas the absence of solvent is indicated by peak absence at 10°. Differential scanning calorimetry (DSC) thermogram confirms the δ to γ phase transition in the 100–150 °C temperature range. As we get an intermingled structure of gel fibers and MWCNTs, therefore, the dielectric behavior showed the percolative nature of the hybrid sPS xerogel. The pure sPS xerogel displayed no response to the frequency change whereas due to interfacial polarization, hybrid sPS xerogel responded to frequency change.

AlYN Thin Films with High Y Content: Microstructure and Performance

Pseudobinary nitride alloys display enhanced piezoelectric properties compared to their nonalloyed counterparts enabling their wide application in high‐performance transducers and acoustic wave resonators. Their fabrication remains challenging because of their inherently stochastic nature, which requires in‐depth understanding of the film growth dynamics and the interplay of deposition parameters. Herein, thin Al1−xYxN films are produced with varied yttrium content in the range fromx = 0.09 to 0.28 on a gradient seed layer on 200‐mm Si substrates and investigated via various X‐ray diffraction methods, high‐resolution scanning transmission electron microscopy, nanoindentation, and atomic force microscopy. Bulk acoustic wave resonators, solidly mounted on a multilayer acoustic isolation, are fabricated to analyze the piezoelectric performance of the films and to extract corresponding material parameters via fitting of the high‐frequency electrical response by 1D Mason's model. The trend of declining coupling is explained by the lattice softening and the increase in electron density, experimentally observed by monitoring reduced elastic modulus and dielectric constant values, respectively. The absence of expected enhancement of the piezoelectric modulus is interpreted by the presence of oxygen impurities, facilitating the inhomogeneous strain of the AlYN lattice, which effectively cancels the energy flattening phenomenon, found in III–V pseudobinary alloys.

Scrutinizing the effect of substrate temperature and enhancing the multifunctional attributes of spray deposited copper gallium sulfide (CuGaS2) thin films

ABSTRACT Polycrystalline chalcopyrite CuGaS2 thin films were prepared using a spray pyrolysis route has been considered a potential material for the solar cell absorber layer. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) studied the impact of substrate temperature in the range of 200–300˚C on surface profile and roughness. Powder X-ray diffraction disclosed that the films were polycrystalline at all examined substrate temperatures, with crystallite size increasing with increased substrate temperature. The UV-Vis displays the cut-off wavelength in 550–880 nm for varied substrate temperatures of CuGaS2 thin films, and the observed band gap is 2.75 eV–1.89 eV. The electrical attributes showed the enhancement in mobility (4.632 cm2 V−1 s−1) for varied substrate temperatures of CuGaS2 thin films. The 300˚C temperature sprayed CuGaS2 polycrystalline films are a decent candidate to be apposite as an absorber layer in thin film photovoltaic solar cells.

Eco-Friendly Synthesis of Ag-ZnO Nanocomposite and its Anti-Bacterial Activity, Photocatalysis Toward Degradation of (CB) Dye and Removal Wastewater Pollution

The zinc oxide, silver particles and the nanocomposite Ag-ZnO were prepared in an easy, fast and environmentally friendly nanoscale method, where these nanomaterials were prepared from nitrates using plant leaf extract Albizia lebbeck, and this environmentally friendly method is safe, nontoxic and nonharmful to the environment, it is a system that is not only cost-effective, but also simple to use and efficient. The reduction reaction can regulate the features and qualities of the resultant chemicals. The researchers used a variety of methods to diagnose and investigate the properties of these nanomaterials, including scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). The results showed the formation of zinc oxide and silver in the form of nanoparticles with good properties, as well as the formation of the nanocomposite Ag-ZnO, and element analysis EDX, and infrared FT-IR, and the results showed the formation of zinc oxide and silver in the form of nanoparticles with good properties, and the results also showed the growth of Ag particles on the surface of the reduced zinc oxide and formation of nanocomposite Ag-ZnO. The photocatalytic degradation of Cibacron Brilliant Yellow 3G-P (CB) dye in the presence of visible light was investigated using Ag-ZnO nanostructures as a photocatalyst. About 1[Formula: see text]g/L of Ag-ZnO with 20[Formula: see text]ppm of the dye produces a greater efficiency in the photocatalysis of the dye in its aqueous solution. The influence of the catalyst amount was explored within the quantities (0.2–0.4–0.6–0.8–1.0–1.2–1.4[Formula: see text]g/L) of the components affecting the photo-smashing process to evaluate the best weight which was 1(g). A photosynthesis ratio was calculated using HCL and NaOH to modify the pH of solutions at a concentration of 5[Formula: see text]ppm, [Formula: see text], 4, 6, 8 and 10. It was also discovered that the acidic function 10 was the best function for breaking down the dye with a 99.1% success rate, and that the shattering reaction followed the kinetics of the first order (Pseudo first), with five consecutive reuses of the best catalyst agents in breaking down the dye Ag-ZnO, was also investigated. After 120[Formula: see text]min, Ag doping ZnO with 10% loading showed photocatalytic elimination of about 93%. and the impact of Ag-ZnO nanocomposite on Staphylococcus aureus and Escherichia coli bacteria was investigated, which were utilized as illustrative examples of the cream-negative bacterium and the positive bacteria, respectively. The findings indicated that the Ag-ZnO nanocomposite had a high rate of success in eradicating and destroying these germs, demonstrating the viability of using a nanoscale solution to sanitize and eradicate microorganisms.

Bond strength of ceramic veneered CAD-milled alloy upon prolonged sintering.

Ceramic-sintering affects bond strength and longevity of metal-ceramic. This study investigated the effect of sintering temperatures and times on metal-ceramic bond strength vis-a-vis interfacial fracture toughness. One hundred eighty rectangular-shaped (25 × 8 × 1mm) casting (Auriloy® (CA)) and CAD-milling (Ceramill Sintron® (MA)) alloys were prepared and randomly veneered with ceramic at normal (930°C; (TN)), increased (940°C; (TI)), and extremely increased (950°C; (TE)) sintering temperatures and normal (1min; (HN)), increased (2min; (HI)), and extremely increased (3min; (HE)) sintering time (n = 10/group). Pre-cracked was subjected to four loading-unloading cycles at 0.05mm/min speed to determine interfacial fracture toughness from strain energy release rate (G). Microstructures were examined with a scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and atomic force microscopy (AFM). ANOVA and Tukey comparisons were determined for significant differences (α = 0.05). Significant differences in G due to the effect of alloy, sintering temperature, and time (p < 0.05) were indicated. MA revealed higher G than CA. Raising temperatures enabled increasing G for CA, not for MA. Extended sintering permitted increasing G for both alloys. Rougher surface of MA than CA was observed. Interfacial ion exchange was differently indicated between CA and MA. Bond strength was influenced by alloy, sintering temperature, and time. Ceramic has better adhesion to MA than CA. Enhancing bond for CA was succeeded through increasing sintering temperature and time, whereas through extended sintering for MA. MA offers stronger bond than CA. Enhancing bond is suggested by extended sintering. Raising temperature can enhance bond for CA, not for MA.

Room temperature excitonic emission in highly aligned ZnO nanostructures prepared by glancing angle Xe+ ion irradiation

Highly aligned ZnO nanostructures have been prepared using glancing angle ion irradiation technique. ZnO thin films were deposited on Si substrates using pulsed laser deposition method. These films were irradiated with 100 keV Xe+ ions of different fluencies ranging from 1 × 1016 to 1 × 1017 ions/cm2 at a glancing angle of 70° with respect to the sample normal. The scanning electron and atomic force microscopy studies reveal a randomly oriented flower petal like structure in the pristine ZnO film. However after ion irradiation, these petals are aligned in the beam direction. Further, with the increase of the ion fluence the petals are transformed to the nanostripe, nanowire like structures and at highest fluence wrinkled structure are formed. Interestingly, on closer examination, these wrinkles consist of nanopillar like structures aligned in the beam direction. The X-ray diffraction analysis reveals that the formed ZnO nanostructures are of hexagonal wurtzite structure with preferred orientation along the c-axis. Further, the ion beam modified nanostructures exhibit interesting photoluminescence emissions in the UV regime. The exciton emission of these ion beam modified ZnO nanostructures has been discussed with the aid of X-ray absorption near edge spectroscopy at O K-edge.

The Effects of Thermal Annealing and Postirradiation on Silver Nanoparticle Films Fabricated by Pulsed Laser Deposition in the Flowless Open Air

Herein, Ag nanoparticle (NP) films are fabricated by pulsed laser deposition technique in the flowless atmospheric air. A Q‐switched Nd:YAG pulsed laser beam is used for the ablation process. The fabricated NP films are postirradiated by the pulsed laser beam. In addition, as‐deposited NP films are annealed in argon gas flow ambient for 45 min at different temperatures (250, 350, and 450 °C), and also annealed at 450 °C for 15, 30, and 45 min. The characteristics of fabricated NP films are investigated after postirradiating by pulsed laser beam, and thermal annealing in Ar gas flow. UV–vis absorption spectroscopy is utilized to provide surface plasmon resonance (SPR) characteristics of films. The results show that thermal annealing can lead to strong enhancement, and also narrowing of the SPR spectrum. The results of field emission scanning electron microscopy and atomic force microscopy show that the annealing and postirradiation processes can influence the NPs size and film structure. As an application, the fabricated film is utilized for surface‐enhanced Raman spectroscopy (SERS) using a 10−6 molar aqueous solution of Rhodamine 6G. The SERS results indicate that the annealed NP films become more sensitive than the as‐deposited films.

Omniphobic coatings based on functional acrylic polymer

Omniphobic coatings were prepared on flat surfaces using a functional acrylic polymer and common micron sized inorganic particles by a simple spray application technique. This coating comprises of a blend of functional acrylic polysiloxane polymer and liquid epoxy resin as a primer base coat followed by spray application of a mixture of organosilanes and inorganic microparticles. The microparticles are fillers commonly used in the paint and coating industry. The resulting surface has the desired surface energy and surface morphology to enable liquid repellency with contact angles of ∼150° for water and 142° for diiodomethane with a roll off angle of <5°. Scanning Electron Microscopic (SEM) and Atomic Force Microscopy (AFM) analysis were performed to study surface morphology. This coating can be applied on large areas and can be cured under ambient conditions. This omniphobic coating is robust, free of nanoparticles and can be used for potential applications in the field of self-cleaning coatings, anti-microbial coatings, and easy cleaning coatings.

Topography of UV-Melanized Thalli of Lobaria pulmonaria (L.) Hoffm.

Lichens are unique extremophilic organisms due to their phenomenal resistance to adverse environmental factors, including ultraviolet (UV) irradiation. Melanization plays a special role in the protection of lichens from UV-B stress. In the present study, we analyzed the binding of melanins with the components of cell walls of the mycobiont of the upper cortex in the melanized lichen thalli Lobaria pulmonaria. Using scanning electron and atomic force microscopy, the morphological and nanomechanical characteristics of the melanized layer of mycobiont cells were visualized. Melanization of lichen thalli led to the smoothing of the surface relief and thickening of mycobiont cell walls, as well as the reduction in adhesion properties of the lichen thallus. Treatment of thalli with hydrolytic enzymes, especially chitinase and lichenase, enhanced the yield of melanin from melanized thalli and promoted the release of carbohydrates, while treatment with pectinase increased the release of carbohydrates and phenols. Our results suggest that melanin can firmly bind with hyphal cell wall carbohydrates, particularly chitin and 1,4-β-glucans, strengthening the melanized upper cortex of lichen thalli, and thereby it can contribute to lichen survival under UV stress.

Effect of NH4Cl on the rusting leaching behavior of metallic phase of iron in reduced ilmenite during TiO2 purification: An electrochemical and density-functional theory study

Ilmenite is the primary feedstock for the manufacturing of titanium goods, however it needs to be refined before the usage. Becher is an eco-friendly process for refining ilmenite by rusting metallic iron from reduced ilmenite to separate iron and TiO2, and NH4Cl is the commonly utilized solvent in this method. In the current study, the contribution of NH4Cl was investigated by comparative analysis of the rusting leaching behavior of iron in the Becher process environment, and the solvents including NH4Cl, CH3COONH4, NaCl and CH3COONa were selected. Electrochemical measurements including potentiodynamic polarization analysis, electrochemical impedance spectroscopy as well as surface morphology analysis utilizing scanning electron microscopy and atomic force microscopy were performed. The obtained results indicate that NH4Cl has the highest rusting rate, with NH3 playing the most important role than Cl−. The presence of ammonia prevents the formation of an oxide film on the iron surface. The DFT calculation reveals the NH3 adsorption on the Fe surface enhances Fe susceptibility to electron loss, consistent with the experimental observation of NH3-accelerated iron corrosion. The obtained understanding and methodology sheds lights on the mechanism of NH4Cl action and offers new insights for the study of rusting leaching catalysts.

AFM is used to study the biophysics of hypertension-induced tachyarrhythmia.

Patients with long-lasting hypertension often suffer from atrial or ventricular arrhythmias. Evidence suggests that mechanical stimulation can change the refractory period and dispersion of the ventricular myocyte action potential through stretch-activated ion channels (SACs) and influence cellular calcium transients, thus increasing susceptibility to ventricular arrhythmias. However, the specific pathogenesis of hypertension-induced arrhythmias is unknown. In this study, through clinical data, we found that a short-term increase in blood pressure leads to a rise in tachyarrhythmias in patients with clinical hypertension. We investigated the mechanism of this phenomenon using a combined imaging system(AC) of atomic force microscopy (AFM) and laser scanning confocal microscopy. After mechanical distraction to stimulate ventricular myocytes isolated from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), we synchronously monitored cardiomyocyte stiffness and intracellular calcium changes. This method can reasonably simulate cardiomyocytes' mechanics and ion changes when blood pressure rises rapidly. Our results indicated that the stiffness value of cardiomyocytes in SHR was significantly more extensive than that of normal controls, and cardiomyocytes were more sensitive to mechanical stress; In addition, intracellular calcium increased rapidly and briefly in rats with spontaneous hypertension. After intervention with streptomycin, a SAC blocker, ventricular myocytes are significantly less sensitive to mechanical stimuli. Thus, SAC is involved in developing and maintaining ventricular arrhythmias induced by hypertension. The increased stiffness of ventricular myocytes caused by hypertension leads to hypersensitivity of cellular calcium flow to mechanical stimuli is one of the mechanisms that cause arrhythmias. The AC system is a new research method to study the mechanical properties of cardiomyocytes. This study provides new techniques and ideas for developing new anti-arrhythmic drugs. HIGHLIGHT: The mechanism of hypertension-induced tachyarrhythmia is not precise. Through this study, it is found that the biophysical properties of myocardial abnormalities, the myocardium is excessively sensitive to mechanical stimulation, and the calcium flow appears to transient explosive changes, leading to tachyarrhythmia.

Self‐Healing and ‐Repair of Nanomechanical Damages in Lead Halide Perovskites

AbstractRecovery from damage in materials helps extend their useful lifetime and of devices that contain them. Given that the photodamages in HaP materials and based devices are shown to recover, the question arises if this also applies to mechanical damages, especially those that can occur at the nanometer scale, relevant also in view of efforts to develop flexible HaP‐based devices. Here, this question is addressed by poking HaP single crystal surfaces with an atomic force microscope (AFM) tip under both ultra‐high vacuum (UHV) and variably controlled ambient water vapor pressure conditions. Sequential in situ AFM scanning allowed real‐time imaging of the morphological changes at the damaged sites. Using methylammonium (MA) and cesium (Cs) variants for A‐site cations in lead bromide perovskites, the experiments show that nanomechanical damages on methylammonium lead bromide (MAPbBr3) crystals heal an order of magnitude faster than Cs‐based ones in UHV. However, surprisingly, under ≥40% RH conditions, cesium lead bromide (CsPbBr3) shows MAPbBr3‐like fast healing kinetics. Direct evidence for ion solvation on CsPbBr3 is presented, leading to the formation of a surface hydration layer. The results imply that moisture improves the ionic mobility of degradation components and leads to water‐assisted improved healing, i.e., repair of nanomechanical damages in the HaPs.