Microscopy Images Research Articles

Molecular-level periodic arrays of long-chain poly(3-hexylthiophene-2,5-diyl) driven by an electric field.

Two-dimensional (2D) periodic arrays of conductive polymers represent attractive platforms for wiring functional molecules into the integrated circuits of molecular electronics. However, the large-scale assembly of polymer periodic arrays at the molecular level faces challenges such as curling, twisting, and aggregation. Here, we assembled the periodic arrays of long-chain poly(3-hexylthiophene-2,5-diyl) (P3HT, Mw = 65 k) at the solid-liquid interface by applying an electric field, within which the charged chain segments were aligned. Atomic force microscopy (AFM) imaging revealed that individual P3HT chains assemble into monolayers featuring face-on orientation, extended chain conformation and isolated packing, which is thermodynamically more stable than folded chains in 2D polycrystals. The assembly process is initiated with the formation of disordered clusters and progresses through voltage-dependent nucleation and growth of extended-chain arrays, wherein continuous conformational adjustments along the nucleation pathway exhibit dependence on the cluster size.

Effective degradation of dyes using silver nanoparticles synthesized from Thunbergia grandiflora leaf extract

Motivated by the urgent need to address dye-related environmental pollution, this study explores the green synthesis of silver nanoparticles (SNPs) using Thunbergia grandiflora leaf extract for its simplicity, affordability, and eco-friendliness. UV–Vis spectroscopy reveals a distinctive signal at 441 nm, while Dynamic Light Scattering shows a zeta potential charge of −18.2 mV, indicating nanoparticle stability. The study demonstrates the catalytic activity of SNPs in degrading industrial dyes Acid Red 88 and Methylene Blue, showcasing first-order kinetics with kinetic constants of 0.18 min−1 and 0.14 min−1, respectively. Moreover, Scanning Electron Microscopic images reveal predominantly spherical nanostructures, while X-ray diffractometry analysis portrays a face-centered crystalline structure. These findings underscore the potential of SNPs synthesized from T. grandiflora leaf extract in nanoremediation efforts, offering a sustainable solution to the pressing challenge of dye-contaminated wastewater, thereby contributing to environmental protection.

Aftermath of Ag embedding on structural, optical, and supercapacitor electrode attributes of USP-grown CuO thin films

Here, ultrasonic spray pyrolysis method (USP) was utilized to produce pure and silver doped copper oxide nanostructures on glass substrates. Thereafter, several characterization techniques were conducted on the grown samples to delve into their morphological, structural, electrochemical, and optical aspects. The mentioned analyses were carried out by performing x-ray photoelectron spectroscopy, scanning electron microscope, X-ray diffraction, electrochemical impedance spectroscopy, galvostatic charge-discharge, cyclic voltammetry, and UV–visible spectroscopy measurements. Thus, the impact of silver impurity doping on the relevant aspects of host material were recorded as well as the features of unspoiled copper oxide films. Accordingly, the samples, as indicated by X-ray diffraction results, possessed (002) preferential plane orientation of copper oxide material along with the crystallite sizes ranging from 52.52 nm to 75.02 nm due to the imperfections caused by the silver doping. The scanning electron microscope images exhibited that the silver doping did not form significant modifications in the host material morphology where nanowire-like structures observed. The presence of the suggested materials in the films was verified by the x-ray photoelectron spectroscopy. Also, the UV–visible spectroscopy measurements detected that optical absorbance edge and bandgap energy values red shifted as a result of the impurity doping. The electrochemical supercapacitors performances of the silver doped copper oxide nanostructured thin films were inspected by using the GCD, EIS, and CV. The silver doped copper oxide films demonstrated a specific capacitance value of 66 F/g at a current density of 1 A/g in 1 M KOH electrolyte. From Nyquist plot, Rs, Rcor, Rpo, Ccor and Cc were obtained as 2.327 × 103 Ω.cm2, 43.63 × 103 Ω.cm2, 4.580 × 103 Ω.cm2, 111.5 × 10-6 S*s^a. cm-2 and 101.1 × 10-6 S*s^a. cm-2, respectively. The results indicated that the electrochemically synthesized the silver doped copper oxide electrodes can be obtained and developed as an alternative electrode material for supercapacitors (SCs).

Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) Self-Reinforced Composites via Solvent-Induced Interfiber Welding of Nanofibers.

In this study, we explore an approach to enhance the mechanical performance of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by utilizing the self-reinforcing effect of β-phase-induced PHBV electrospun nanofiber mats. This involves electrospinning combined with low-temperature postspun vapor solvent interfiber welding. Scanning electron microscopy imaging confirmed fiber alignment, while XRD diffraction revealed the presence of both α and β crystalline phases under optimized electrospinning conditions. The resulting composite exhibited significant improvements in mechanical properties attributed to the formation of more perfectly structured α and β polymorphs and enhanced interfacial adhesion of electrospun nanofibers after vapor solvent treatment. This approach offers entirely recyclable and biodegradable materials, presenting the potential for a new family of sustainable bioplastics.

Shifting to biology promotes highly efficient iron removal in groundwater filters

Rapid sand filters are established and widely applied technologies for groundwater treatment. In these filters, main groundwater contaminants such as iron, manganese, and ammonium are oxidized and removed. Conventionally, intensive aeration is employed to provide oxygen for these redox reactions. While effective, intensive aeration promotes flocculent iron removal, which results in iron oxide flocs that rapidly clog the filter. In this study, we operated two parallel full-scale sand filters at different aeration intensities to resolve the relative contribution of homogeneous, heterogeneous and biological iron removal pathways, and identify their operational controls. Our results show that mild aeration in the LOW filter (5 mg/L O2, pH 6.9) promoted biological iron removal and enabled iron oxidation at twice the rate compared to the intensively aerated HIGH filter (>10mg/L O2, pH 7.4). Microscopy images showed distinctive twisted stalk-like iron solids, the biosignatures of Gallionella ferruginea, both in the LOW filter sand coatings as well as in its backwash solids. In accordance, 10 times higher DNA copy numbers of G. ferruginea were found in the LOW filter effluent. Clogging by biogenic iron solids was slower than by chemical iron flocs, resulting in lower backwash frequencies and yielding four times more water per run. Ultimately, our results reveal that biological iron oxidation can be actively controlled and favoured over competing physico-chemical routes. The production of more compact and practically valuable iron oxide solids is of outmost interest. We conclude that, although counterintuitive, slowing down iron oxidation in the water before filtration enables rapid iron removal in the biofilter.

Rosmarinic acid turned α-syn oligomers into non-toxic species preserving microtubules in Raw 264.7 cells

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder worldwide, and the therapeutic is focused on several approaches including the inhibition of fibril formation by small compounds, avoiding the formation of cytotoxic oligomers. Thus, we decided to explore the capacity of compounds carrying catechol moieties to inhibit the progression of α-synuclein. Overall, the compounds rosmarinic acid (1), carnosic acid (2), carnosol (3), epiisorosmanol (4), and rosmanol (5) avoid the progression of fibril formation assessed by Thiofavine T (ThT), and atomic force microscopy images showed that morphology is influenced for the actions of compounds over fibrillization. Moreover, ITC experiments showed a Kd varying from 28 to 51 µM, the ΔG showed that the reaction between compounds and α-syn is spontaneous, and ΔH is associated with an exothermic reaction, suggesting the interactions of hydrogen bonds among compounds and α-syn. Docking experiments reinforce this idea showing the intermolecular interactions are mostly hydrogen bonding within the sites 2, 9, and 3/13 of α-synuclein, and compounds 1 and 5. Thus, compound 1, rosmarinic acid, interestingly interacts better with site 9 through catechol and Lysines. In cultured Raw 264. 7 cells, the presence of compounds showed that most of them can promote cell differentiation, especially rosmarinic acid, and rosmanol, both preserving tubulin cytoskeleton. However, once we evaluated whether or not the aggregates pre-treated with compounds could prevent the disruption of microtubules of Raw 264.7 cells, only pre-treated aggregates with rosmarinic acid prevented the disruption of the cytoskeleton. Altogether, we showed that especially rosmarinic acid not only inhibits α-syn but stabilizes the remaining aggregates turning them into not-toxic to Raw 264.7 cells suggesting a main role in cell survival and antigen processing in response to external α-syn aggregates.

Improving correlation based super-resolution microscopy images through image fusion by self-supervised deep learning

Super-resolution imaging is a powerful tool in modern biological research, allowing for the optical observation of subcellular structures with great detail. In this paper, we present a deep learning approach for image fusion of intensity and super-resolution optical fluctuation imaging (SOFI) microscopy images. We construct a network that can successfully combine the advantages of these two imaging methods, producing a fused image with a resolution comparable to that of SOFI and an SNR comparable to that of the intensity image. We also demonstrate the effectiveness of our approach experimentally, specifically on cell samples where microtubules were stained with ATTO647N and imaged using a confocal microscope with a single photon fiber bundle camera, allowing for the simultaneous acquisition of an image scanning microscopy (ISM) image and a SOFISM (ISM and SOFI) image. Our network is designed as a self-supervised network and shows the ability to train on a single pair of images and to generalize to other image pairs without the need for additional training. Our approach offers a flexible and efficient way to combine the strengths of correlation based imaging techniques along with traditional intensity based microscopy, and can be readily applied to other fluctuation based imaging modalities.

Evaluation of the Loss of Surface Roughness Following the Use of Four Different Instruments for Mechanical Debridement of Dental Implants: An In-vitro Pilot Study

To compare the dental implant surface properties such as mean surface roughness, roughness depth, and the surface loss produced by different prophylactic instrument types. Twenty-four surfaces of twelve dental implants were treated using titanium curettes, titanium-coated curettes, an air abrasion unit, and titanium brushes. The dental implants were inserted partially into a Styrofoam base, exposing one-third to simulate cases of peri-implantitis. The exposed surface was coated with artificial dental calculus (ADC) and divided into four groups for treatment. The arithmetic mean surface roughness (Ra) and the mean roughness depth (Rz) were assessed using the confocal microscope, and the surface loss (SL) area was calculated from the scanning electron microscopic images using an image analysis software. The Ra value varied between 1.08 to 0.29 µm, the Rz value between 10.3 to 70.5 µm, and the mean surface loss area between 154 to 9410 µm2. The One-way ANOVA analysis showed a statistically significant difference between the four groups (P < 0.05). The air abrasion unit showed the highest mean roughness value of 1.08 ± 0.14 µm, mean roughness depth of 70.5 ± 2.21 µm, and a minor surface area loss of 154 ± 132 µm2. In comparison, the titanium brushes showed the least Ra and Rz of 0.29 ± 0.05 µm and 10.3 ± 2.32 µm, respectively, whereas the titanium-coated curettes showed the highest loss of surface area 9410 ± 91.6 µm2. The air abrasion unit was shown to have the least detrimental effect on the implant surface when removing the artificial dental calculus compared to the other three methods.

Highly efficient Rh-doped MnO2 nanocatalysts for complete elimination of CO at room temperature.

Obliteration of carbon monoxide is significant due to its hazardous effect on human health and potential application in different fields. Catalytic CO oxidation at lower temperature is the most convenient method to diminish the toxicity of CO. The low-cost catalysts which are exhibiting higher activity at lower temperature with good stability are in demand. The nanosized Rh-doped MnO2 catalysts have been prepared by dextrose-assisted co-precipitation method. Catalytic CO oxidation reaction was carried out over these prepared nanocatalysts under environmentally suitable conditions. XRD confirms the phase formation of prepared catalysts. These samples exhibit rod-like morphology with thickness of rods of less than 10nm which is substantiated from electron microscopy images. XPS data reveals the oxidation state of Mn (+ 4) and Rh (+ 3). These catalysts are highly active for CO oxidation reaction at lower temperature, and one showed complete CO conversion at room temperature. The time-on-stream studies revealed that these catalysts are highly stable for CO oxidation for several hours. These catalysts are decidedly stable in moist condition and also showed higher activity in the presence of moisture, indicating participation of moisture in the oxidation reaction at above room temperatures.

Clarification of the spontaneous polarization direction in crystals with wurtzite structure

The wurtzite structure is one of the most frequently found crystal structures in modern semiconductors and its inherent spontaneous polarization is a defining materials property. Despite this significance, confusion has been rampant in the literature with respect to the orientation of the spontaneous polarization inside the unit cell of the wurtzite structure, especially for the technologically very relevant III-N compounds (AlN, GaN, and InN). In particular, the spontaneous polarization has been reported to either point up or down for the same unit cell orientation, depending on the literature source—with important implications for, e.g., the carrier type and density expected at interfaces of heterostructures involving materials with the wurtzite structure. This perspective aims to resolve this ambiguity by reviewing available reports on the direction of the energetically preferred polarization direction in the presence of external electric fields as well as atomically resolved scanning transmission electron microscopy images. While we use ferroelectric wurtzite Al1−xScxN as a key example, our conclusions are generalizable to other compounds with the same crystal structure. We demonstrate that a metal-polar unit cell must be associated with an upward polarization vector—which is contrary to long-standing conventional wisdom.

Influence of Topography on Nano-Mechanical Properties of Cylindrical Magnetron Sputtered TiN Films

Abstract Numerous studies on Nano-mechanical behavior of the thin films explained primarily in terms of their film morphology and particle size rather than film topography. Therefore, the current study investigates the effect of film topography on the nano-mechanical characteristics of the film. Ti/TiN multilayer thin films were deposited at varying deposition pressures by using an indigenously developed Cylindrical Magnetron Sputtering (CMS) unit. Surface crystallographic information is characterized by synchrotron-based Grazing Incidence XRD analysis. Film growth follows self-assembled nano hill architecture as revealed by AFM and in-situ Scanning Probe Microscopy images. The tribo-mechanical properties of the film is dependent on the height and spacing of its self-assembled structure, which experiences either crushing or buckling under the indenter load, thereby affecting film characteristics. Film deposited at moderate pressure exhibits superior wear behavior, attributed to the interplay between Plasticity Index (PI) and Depth Recovery Ratio (DRR). The study primarily focused on film growth phenomena by using cylindrical targets and their influence on nanomechanical properties of the film.&amp;#xD;

Investigating structural property of human hair by using infrared free electron lasers

Intense infrared (IR) rays can heat matters and evaporate waters thermally. One of the possible applications will be hair dryer, although the irradiation effects of IR rays on the hair have not been fully explored. In this study, we first examined the interaction of IR rays at various wavelengths from 3.0 µm (near IR) to 90 µm (far IR) with the surface structure of human hair by using IR free electron lasers (FELs). IR-FEL is an accelerator-based pico-second pulse laser, and the feature is the wavelength-tunability with the high-photon density. When one thread of hair was irradiated by the FEL of 6–7 mJ energy at 60 µm, the cleavage occurred, and the morphological destruction was observed on scanning-electron microscopy images after the irradiations at 70 µm and 6.1 µm (amide I). Synchrotron-radiation infrared microspectroscopy showed that those FEL irradiations decreased a shoulder band at 1710 cm−1 that corresponds to carboxyl group in melanin or fatty acids and increased absorption intensity at 500–600 cm−1. On the contrary, the FEL at 90 µm little changed either the surface morphology or the infrared absorption spectra. Interestingly, near-IR FELs at 3.0–3.5 µm induced bending of a hair, and 2D mapping of protein secondary conformations revealed that β-sheet was more increased than the other conformations on the surface of the bending area even at low pulse energy (1–3 mJ). As a result, the structural damage of the hair was least at 90 µm, which implies an ideal wavelength for drying hair mildly.

Effect of ultrasound/CaCl2 co-treatment on the microstructure, gelatinization, and film-forming properties of high amylose corn starch

The effect of ultrasound/CaCl2 co-treatment on aggregation structure, thermal stability, rheological, and film properties of high amylose corn starch (HACS) was investigated. The scanning electron microscopy (SEM) images revealed the number of starch fragments and malformed starch granules increased after co-treatment. The differential scanning calorimetry (DSC) results showed the co-treated HACS got a lower gelatinization temperature (92.65 ± 0.495 °C) and enthalpy values (ΔH, 4.14 ± 0.192 J/g). The optical microscope images indicated that lesser Maltase crosses were observed in co-treated HACS. The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated ultrasound influenced the compactness of amorphous zone and CaCl2 damaged the crystalline region of HACS granules. Additionally, the rheology properties of HACS dispersion demonstrated the apparent viscosity of co-treated dispersion increased as the ultrasound time prolonged. The mechanical strength and structural compactness of HACS films were improved after ultrasound treatment. The mechanism of ultrasound/CaCl2 co-treatment improved the gelatinization and film-forming ability of HACS was that (i) ultrasound wave loosened the HACS granules shell, promoted the treatment of CaCl2 on HACS granules, and (ii) ultrasound wave improved the uniform distribution of HACS dispersion, increased the interaction between CaCl2 and starch chains during the process of film-forming.

Elucidating bacterial coaggregation through a physicochemical and imaging surface characterization

Bacterial coaggregation is a highly specific type of cell-cell interaction, well-documented among oral bacteria, and involves specific characteristics of the cell surface of the coaggregating strains. However, the understanding of the mechanisms promoting coaggregation in aquatic systems remains limited. This gap is critical to address, given the broad implications of coaggregation for multispecies biofilm formation, water quality, the performance of engineered systems, and diverse biotechnological applications. Therefore, this study aims to comprehensively characterize the cell surface of the coaggregating strain Delftia acidovorans 005P, isolated from drinking water, alongside a non-coaggregating strain, D. acidovorans 009P. By analyzing two strains of the same species, we aim to identify the factors contributing to the coaggregation ability of strain 005P. To achieve this, we employed a combination of physicochemical characterization, Fourier-transform infrared spectroscopy (FTIR), and advancing imaging techniques [transmission electron microscopy and cryo-electron tomography (cryo-ET)]. The coaggregating strain (005P) exhibited higher surface hydrophobicity, negative surface charge, and cell surface and co-adhesion energies than the non-coaggregating strain (009P). The chemical characterization of bacterial surfaces through FTIR revealed subtle differences, particularly in spectral regions linked to carbohydrates and phosphodiesters/amide III of proteins (860–930 cm−1 and 1212–1240 cm−1, respectively). Cryo-ET highlighted significant differences in pili structures between the strains, such as variations in length, frequency, and arrangement. The pili in the 005P strain, identified as pili-like adhesins, serve as key mediators of coaggregation. By integrating physicochemical analyses and high-resolution imaging techniques, this study conclusively links the coaggregation ability of D. acidovorans 005P to its unique pili characteristics, emphasizing their crucial role in microbial coaggregation in aquatic environments.

Full-Automatic High-Efficiency Mueller Matrix Microscopy Imaging for Tissue Microarray Inspection

This paper proposes a full-automatic high-efficiency Mueller matrix microscopic imaging (MMMI) system based on the tissue microarray (TMA) for cancer inspection for the first time. By performing a polar decomposition on the sample’s Mueller matrix (MM) obtained by a transmissive MMMI system we established, the linear phase retardance equivalent waveplate fast-axis azimuth and the linear phase retardance are obtained for distinguishing the cancerous tissues from the normal ones based on the differences in their polarization characteristics, where three analyses methods including statistical analysis, the gray-level co-occurrence matrix analysis (GLCM) and the Tamura image processing method (TIPM) are used. Previous MMMI medical diagnostics typically utilized discrete slices for inspection under a high-magnification objective (20×–50×) with a small field of view, while we use the TMA under a low-magnification objective (5×) with a large field of view. Experimental results indicate that MMMI based on TMA can effectively analyze the pathological variations in biological tissues, inspect cancerous cervical tissues, and thus contribute to the diagnosis of postoperative cancer biopsies. Such an inspection method, using a large number of samples within a TMA, is beneficial for obtaining consistent findings and good reproducibility.

The influence of vesicularity on grain morphology in basaltic pyroclasts from Mauna Loa and Kīlauea volcanoes

Vesicularity of individual pyroclasts from airfall tephra deposits is an important parameter that is commonly measured at basaltic volcanoes. Conventional methods used to determine pyroclast vesicularity on a large number of clasts has the potential to be time consuming, particularly when rapid analysis is required. Here we propose dynamic image analysis on two-dimensional (2D) projection shapes of crushed pyroclasts from tephra deposits as a new method to estimate vesicularity. This method relies on the influence of vesicles and uses grain morphology as a proxy for vesicle size and abundance. Pyroclasts from a variety of basaltic tephra deposits from the volcanoes of Mauna Loa and Kīlauea were analyzed. Vesicularities between 52–98% were measured via nitrogen-gas pycnometry. The same pyroclasts were then crushed and sieved, and their grain shapes measured using dynamic image analysis on a CAMSIZER®. This yields values for the mean sphericity, elongation, compactness, and Krumbein roundness of the grains. Our data show that grains become increasingly irregular with increasing vesicularity, with the degree of correlation between shape parameters and vesicularity depending on the size of measured grains. Shape irregularities in small grains (60–250 µm) are mostly area-based, with elongation being the best vesicularity indicator, whereas shape irregularities in large grains (250–700 µm) are mostly perimeter-based, with Krumbein roundness as the best vesicularity indicator. Using mean shape parameter values with all grain sizes included, grain elongation is the most well-correlated shape parameter with vesicularity, with the best fitted model explaining 76% of variation in the observations. Microscope images of thin sections of intact pyroclasts, as well as from crushed pyroclasts, were analyzed using CSDCorrections 1.6 software in ImageJ to find local vesicularity, vesicle size, grain size, grain elongation, and vesicle spatial distribution by stereological conversion. Observed correlation between grain shape and vesicularity can be explained by the local effect of vesicles on the shape of the solid structure in between those vesicles. Grain shape depends not only on vesicularity, but also on vesicle to grain size ratio and the spatial distribution of vesicles. The influence of vesicles on grain shape is best captured by grains with the size of the solid structure in between vesicles, which generally increases with decreasing vesicularity. Dynamic image analysis is a useful tool to quickly gauge vesicularity, which could be used in near-real-time during an eruption response. However, this method is best suited for highly vesicular (> 80%) basaltic pyroclasts from tephra deposits with few microlites and phenocrysts. Further research on crushing techniques, optimum grain size for shape measurements, and Krumbein roundness measurements for the grain size range of 250–700 µm might enable application of this method to lower vesicularity pyroclasts.

Enhanced healing of burn wounds by multifunctional alginate-chitosan hydrogel enclosing silymarin and zinc oxide nanoparticles

Multifunctional wound dressings have been applied for burn injuries to avoid complications and promote tissue regeneration. In the present study, we fabricated a natural alginate-chitosan hydrogel comprising silymarin and green-synthesized zinc ‎oxide ‎nanoparticles (ZnO NPs). Then, the physicochemical attributes of ZnO NPs and loaded hydrogels were analyzed. Afterward, wound healing efficacy was evaluated in a rat model of full-thickness dermal burn wounds. The findings indicated that ZnO NPs were synthesized via reduction with phytochemicals from Elettaria cardamomum seeds extract. The microscopic images exhibited fairly spherical ZnO NPs (35–45 nm), and elemental analysis verified the relevant composition. The hydrogel, containing silymarin and biosynthesized ZnO NPs, displayed a uniform appearance, smooth surfaces, and a porous structure. Moreover, infrared spectroscopy ‎identified functional groups, confirming the successful loading without adverse interactions. The obtained hydrogel exhibited great water absorption, high porosity, sustainable degradation for several days, and enhanced antioxidant capability of the combined loaded component. In vivo studies revealed faster and superior wound healing, achieving nearly complete closure by day 21. Histopathology confirmed improved cell growth, tissue regeneration, collagen deposition, and neovascularization. It is believed that this multifunctional hydrogel-based wound dressing can be applied for effective burn wound treatment.

Overcoming data scarcity in biomedical imaging with a foundational multi-task model.

Foundational models, pretrained on a large scale, have demonstrated substantial success across non-medical domains. However, training these models typically requires large, comprehensive datasets, which contrasts with the smaller and more specialized datasets common in biomedical imaging. Here we propose a multi-task learning strategy that decouples the number of training tasks from memory requirements. We trained a universal biomedical pretrained model (UMedPT) on a multi-task database including tomographic, microscopic and X-ray images, with various labeling strategies such as classification, segmentation and object detection. The UMedPT foundational model outperformed ImageNet pretraining and previous state-of-the-art models. For classification tasks related to the pretraining database, it maintained its performance with only 1% of the original training data and without fine-tuning. For out-of-domain tasks it required only 50% of the original training data. In an external independent validation, imaging features extracted using UMedPT proved to set a new standard for cross-center transferability.

A new insight into largely defocused HAADF-STEM imaging and visualization of strain field

A crystalline bilayer specimen with a semi-coherent interface can generate moiré fringes in the high-angle annular-dark field scanning transmission electron microscopy (HAADF-STEM) imaging. Moreover, when the probe is significantly defocused, this specimen can produce largely defocused probe (LDP)-STEM patterns. Although the electron channeling effect serves as the fundamental principles for HAADF-STEM imaging, its connection to the emergence of LDP-STEM patterns remains unclear. The missing link lies in identifying the location of the imaged region. To address this issue, we examined the strain field in three-dimensional space and its interaction with the convergent electron beam, taking the PbZrO3/SrTiO3 (PZO/STO) heterostructure as an example. We discovered a new intensity relationship for LDP-STEM patterns in the PZO/STO heterostructure, which can be well explained by our theory. We also found that, generated by imaging the strain zone, these patterns revealed information that might be obscured in traditional high resolution STEM images, showing a unique advantage in characterizing the strain field. Furthermore, we provided discussions on visualizing the strain field, including the misfit dislocation network and array. Our research offers a novel perspective on the LDP-STEM imaging and clarifies the approach to characterizing the strain field.

White Light Emission from Zn(II) and DMSO-Induced Copper Nanocluster Assembly.

An assembly of metal nanoclusters driven by appropriate surface ligands and solvent environment may engender entirely new photoluminescence (PL). Herein, we first synthesize histidine (His) stabilized copper nanoparticles (CuNPs) and, subsequently, copper nanoclusters (CuNCs) from it using 3-mercaptopropionic acid (MPA) as an etchant. The CuNCs originally emit bluish-green (λem=470 nm) PL with a low quantum yield (QY∼1.8%). However, it transformed into a dual-emissive nanocluster assembly (Zn-CuNCs) in the presence of Zn(II) salt, having a distinct blue emission band (λem = 420 nm) and a red emission band (λem = 615 nm) with eight times QY (∼9.1%) enhancement. Adding dimethyl sulfoxide (DMSO) further modifies the emission intensities; the red band was amplified four times, while the blue band was diminished by 2.5 times. The transmission electron microscopy (TEM) images unveiled that the Zn-CuNCs are a large assembly of tiny nanoclusters, which become more compact in DMSO. The blue emission possesses steady-state fluorescence anisotropy, while the red emission shows no anisotropy. Further, near-perfect white light emission(WLE) was rendered with CIE coordinates of (0.33, 0.32) by combining the dual emission of the Zn-CuNCs with the original green emission of the CuNCs.