Microscopy Images Research Articles

Structural, Surface, and Optical Properties of Nitrogen-Doped Al:ZnO (NAZO) Thin Films Produced by a Thermionic Vacuum Arc Deposition Technology

Nitrogen (N)-doped Al:ZnO (NAZO) thin films were deposited on glass and indium tin oxide (ITO) coated glass by a thermionic vacuum arc (TVA) technique. The structural, surface morphology, and optical properties of the produced thin films were characterized by X-ray diffractometry (XRD), atomic force microscopy (AFM), and ultraviolet-visible spectroscopy. The microstructure properties of the produced thin films on two substrates were compared, and metal oxide phases were observed in the XRD patterns and photoluminescence spectra. 2.75, 3.10, and 3.30 eV band gaps were detected. The transmittance values were approximately 90% and 60% for the film deposited onto uncoated and ITO-coated glass, respectively. According to field-emission scanning electron microscopy and atomic force microscopy images, the crystallite size is nanoscale, and its dimensions are approximately 60 and 20 nm for the film deposited onto uncoated and ITO-coated glass substrates, respectively. Atomic ratios of zinc/aluminum were 9.25/0.56, and 5.42/0.22 for uncoated and ITO-coated glass substrate, respectively. All samples were coated with the same coating process, and no post-annealing process was applied to the sample.

Acoustic Resolution Photoacoustic Microscopy Imaging Enhancement: Integration of Group Sparsity With Deep Denoiser Prior

Acoustic Resolution Photoacoustic Microscopy Imaging Enhancement: Integration of Group Sparsity With Deep Denoiser Prior

Meso-Substituted AB3-type phenothiazinyl porphyrins and their indium and zinc complexes photosensitising properties, cytotoxicity and phototoxicity on ovarian cancer cells.

New meso-substituted AB3-type phenothiazinyl porphyrins and ferrocenylvinyl phenothiazinyl porphyrin were synthesised by Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions, respectively. The free porphyrins were further used in the synthesis of new indium(iii) or zinc(ii) porphyrin complexes. All porphyrins exhibit red fluorescence emission in solution, a property that remains unimpaired following internalisation in ovarian A2780 cancer cells, as evidenced by fluorescence microscopy images. The In(iii) phenothiazinyl porphyrin complexes show a higher quantum yield of fluorescence emission (2aΦ F = 30%, 4aΦ F = 29%, 5aΦ F = 28%) compared to the free base porphyrin precursors, or Zn(ii) complex 4b (Φ F = 10%). The potential of novel phenothiazinyl porphyrins to act as photosensitisers was evaluated using two distinct approaches. The first was through the measurement of the singlet oxygen quantum yield Φ Δ(1O2), while the second employed in vitro measurements of metabolic activity, oxidative stress, nuclear factor-erythroid 2 related factor 2 (Nrf-2) activation and tumour necrosis factor-alpha (TNF-α) under both dark and light irradiation conditions. As reflected by the IC50 values, the most potent cytotoxicity of the phenothiazinyl porphyrins against the A2780 cells was observed for In(iii) ferrocenylvinyl phenothiazinyl porphyrin 4a (36.38 μM), the remaining compounds are less cytotoxic. The reduction in metabolic activity was observed in A2780 ovarian tumour cells treated with 4a and 6a and exposed to light compared to treatment in the absence of light. The oxidative stress, TNF-α and Nrf-2 transcription factor were particularly notable when A2780 cells were treated with 4a and subsequently photoirradiated, the oxidative stress was linked to the highest value of Φ Δ(1O2) recorded for 4a (60%).

Plasma-induced nanogap narrowing and morphological transformation in gold nanoparticle assemblies.

The plasmonic properties of gold nanoparticle (AuNP) assemblies are critically influenced by the nanogaps between particles. Here, we demonstrate that plasma treatment effectively narrows these nanogaps and ultimately merges the nanoparticles. This process induces a sequential redshift, weakening, broadening, and an eventual blueshift of the plasmon coupling peak in UV-vis spectra, indicating transitions from classical to quantum regimes and finally to contact modes. Surface-enhanced Raman spectroscopy reveals an initial increase in intensity as the nanogaps narrow, followed by a decline as linker molecules are removed. Transmission electron microscopy images further show significant deformation of AuNPs after 5 min of plasma treatment. Based on these combined observations, we propose that the oxidative desorption of thiol linkers causes the collapse of self-assembled monolayers, leading to the gradual narrowing of nanogaps and eventual particle fusion. This plasma-induced transformation also enables the creation of novel AuNP shapes, such as nano-snowmen and particles with protruding morphologies, by merging heterodimers or core-satellite structures. Our findings not only deepen the understanding of plasma effects on nanoparticle assemblies but also expand the utility of plasma treatment for controlling nanogap distances and fabricating exotic nanoparticle shapes.

High-Resolution Electron Microscopy Imaging of MOFs at Optimized Electron Dose

Local and high-resolution structural investigation of metal-organic frameworks (MOFs) is essential for understanding the role of defects and incorporated elements. In this paper, we characterize the structure of metalated versions...

A critical review of in-situ moisture distribution detection and characterization techniques utilizing deep dewatering for organic waste.

Deep dewatering is crucial for effectively reducing the volume of organic waste and facilitating its downstream transportation and disposal. An in-depth understanding of the occurrence states, composition, and morphological characteristics of moisture in organic waste is the basis for optimizing the dewatering process, improving dewatering efficiency, and reducing energy consumption. Given the common problems of time-consuming, low sensitivity, and poor parallelism of traditional methods, this work reviews the advanced in-situ analysis methods for moisture distribution of organic waste. The Raman microscopy imaging technique is highlighted to provide a new approach for visualizing the spatial distribution of moisture with different binding strengths in solid flocs. Various physical, chemical, and biological characteristics and characterization methods of organic waste related to deep dewatering are introduced, and they are correlated with conditioning methods. Almost all conditioning will cause changes in the physical characteristics of organic waste, while the improvement of dewatering performance is actually caused by changes in the chemical composition and biological characteristics of the matrix, and these characteristics are intrinsically related to the moisture distribution. The characterization and in-situ moisture detection methods presented in this work aim to support future studies in understanding changes in material composition related to improving dewatering performance and further clarifying the mechanisms of deep dewatering of organic wastes.

Design of Meta-surface Lens Combining with Pupil Filter

Metasurface lenses are miniature flat lenses that achieve precise control of the phase, amplitude, and polarization of incident light by modulating the parameters of each unit on the substrate. Compared with conventional optical lenses, they have the advantages of small size, light weight, and high integration, and are the core components of photonic chips. Currently, the hot topics for metasurface lens are broadband and achromatic devices, and there is still little attention paid to the resolution improvement. To break through the diffraction limit and further improve the focusing performance and imaging resolution of metasurface lenses, we use unit cells to perform multi-dimensional modulation of the incident light field. Specifically, in this paper, we combine phase modulation of metasurface lens with a pupil filtering for the first time, which has been widely applied in traditional microscopy imaging and adaptive optics, and has demonstrated powerful resolution enhancement effects. The fusion of these two technologies will continue to improve the imaging performance of metasurface lenses and expand their application fields.<br>In this article, we firstly design a single-cell super-surface lens composed of a Silicon nanofin array and a silica substrate as a benchmark for comparing the performance of fused super-surface lens. The lens achieves an ideal focal spot for incident light at 633 nm, resulting in a FWHM of 376.0 nm. Then, a three-zone phase modulating pupil filter was proposed and designed with the same aperture of metasurface lens, which has a phase jump of 0-π-0 from inside to outside of the aperture. From the simulation results, the main lobe size of the focal spot has been compressed obviously. In the optimization, its structural parameters were scanned for the best performance, and the optimal set of structural parameters was selected and applied in the fusion metasurface lens. Finally, the fused metasurface lens was designed by combining the metasurface lens with the three-zone phase modulating pupil filter, and the FWHM of its focal spot was compressed to 323.4 nm (≈0.51λ), which is not only 15% smaller than original metasurface lens’s FWHM of 376.0 nm, but also much smaller than the diffraction limit of 0.61λ/NA (when NA=0.9, it is approximately 429.0 nm). This result preliminarily demonstrates the super-resolution performance of the fused super-surface lens. With the comprehensive regulation of multi-dimensional information, such as amplitude, polarization, and vortex, the fused super-surface optical lens will achieve more excellent super-resolution focusing and imaging performance, and will also be widely used in the fields of super-resolution imaging, virtual reality, and 3-D optical display, due to its characteristics of high resolution, high integration, and high miniaturization.

Representative Training Data Sets Are Critical for Accurate Machine-Learning Classification of Microscopy Images of Particles Formed by Lipase-catalyzed Polysorbate Hydrolysis.

Polysorbate 20 (PS20) is commonly used as an excipient in therapeutic protein formulations. However, over the course of a therapeutic protein product's shelf life, minute amounts of co-purified host-cell lipases may cause slow hydrolysis of PS20, releasing fatty acids (FAs). These FAs may precipitate to form subvisible particles that can be detected and imaged by various techniques, e.g., flow imaging microscopy (FIM). Images of particles can then be classified using supervised convolutional neural networks (CNNs). However, CNNs should be trained on representative images of particles which, as we demonstrate in this work, may be challenging to obtain. Here, we tested several rapid techniques to create FA particles and examined whether CNNs trained on microscopy images of these rapidly formed particles could accurately classify images of particles that had been produced by kinetically slower lipase-catalyzed hydrolysis of PS20. CNNs trained on images of rapidly produced particles were less accurate in classifying images of FA particles that had been produced by enzymatic hydrolysis of PS20 than CNNs trained with images of particles generated by the same slow hydrolysis, highlighting the importance of using representative image data sets for training CNN classifiers.

Synergistic effect and mechanism of ferric ion modified citric acid depressant in the flotation separation of scheelite from cassiterite

Scheelite and cassiterite often coexist in skarn deposits, which are prone to excessive crushing during dissociation, and gravity separation faces a challenge. However, research on flotation separation is limited. This study aimed to investigate the selective depression behavior and depression mechanism of a combined depressant containing ferric chloride and citric acid on cassiterite to successfully achieve the flotation separation of scheelite and cassiterite. Experimental studies on single minerals and artificially mixed minerals indicated that the individual ferric chloride or citric acid exhibited weak depressive abilities and poor selectivity toward cassiterite. However, a combination of ferric chloride and citric acid in a mass ratio of 3:7 achieved better separation results. At a pH of 8, with a concentration of 1 × 10–3 mol/L mixed depressant, and a sodium oleate concentration of 5 × 10–5 mol/L, scheelite and cassiterite exhibited recovery of 73.35 % and 19.98 %, with grades of 61.76 % and 16.18 %, respectively. Fourier–transform infrared spectroscopy and X–ray photoelectron spectroscopy analyses revealed that the mixed depressant strongly chemically adsorbed on the cassiterite surface, forming FeOOH at ferric species sites. Contact angle measurements indicated a significant reduction in surface hydrophobicity of the cassiterite surface due to mixed depressant components. Atomic force microscopy imaging analysis elucidated the adsorption morphology of the mixed depressant depressive component FeOOH on the cassiterite surface in both 2D and 3D imaging, indicating abundant high–intensity reagent peak adsorption. Therefore, the mixed depressant enhanced the selectivity of the depressant, facilitating the effective separation of scheelite and cassiterite.

Anionic polymer coating for enhanced delivery of Cas9 mRNA and sgRNA nanoplexes.

Polymeric carriers have long been recognized as some of the most effective and promising systems for nucleic acid delivery. In this study, we utilized an anionic di-block co-polymer, PEG-PLE, to enhance the performance of lipid-modified PEI (C14-PEI) nanoplexes for delivering Cas9 mRNA and sgRNA targeting KRAS G12S mutations in lung cancer cells. Our results demonstrated that PEG-PLE, when combined with C14-PEI at a weight-to-weight ratio of 0.2, produced nanoplexes with a size of approximately 140 nm, a polydispersity index (PDI) of 0.08, and a zeta potential of around -1 mV. The PEG-PLE/C14-PEI nanoplexes at this ratio were observed to be both non-cytotoxic and effective in encapsulating Cas9 mRNA and sgRNA. Confocal microscopy imaging revealed efficient endosomal escape and intracellular distribution of the RNAs. Uptake pathway inhibition studies indicated that the internalization of PEG-PLE/C14-PEI primarily involves scavenger receptors and clathrin-mediated endocytosis. Compared to C14-PEI formulations, PEG-PLE/C14-PEI demonstrated a significant increase in luciferase mRNA expression and gene editing efficiency, as confirmed by T7EI and ddPCR, in A549 cells. Sanger sequencing identified insertions and/or deletions around the PAM sequence, with a total of 69% indels observed. Post-transfection, the KRAS-ERK pathway was downregulated, resulting in significant increases in cell apoptosis and inhibition of cell migration. Taken together, this study reveals a new and promising formulation for CRISPR delivery as potential lung cancer treatment.

In Vitro Osteogenic Response to Copper-Doped Eggshell-Derived Hyroxyapatite With Macrophage Supplements.

The high bioactivity and biocompatibility of hydroxyapatite (HAP) make it a useful bone graft material for bone tissue engineering. However, the development superior osteoconductive and osteoinductive materials for bone regeneration remains a challenge. To overcome these constraints, Cu-doped hydroxyapatite (HAP(Cu)) from waste eggshells has been produced for bone tissue engineering. The materials produced were characterized using Fourier transform infrared spectroscopy, x-ray diffraction, and photoelectron spectroscopy. The scanning microscopy images revealed that the developed HAP was a rod-like crystalline structure with a typical 80-150 nm diameter. Energy-dispersive x-ray spectroscopy showed that the generated HAP was mostly composed of calcium, oxygen, and phosphorus. The Ca/P molar ratios in eggshell-derived and copper-doped HAP were 1.61 and 1.67, respectively, similar to the commercially available HAP ratio (1.67). The WST-8 assay was used to assess the biocompatibility of HAPs with hBMSCs. HAP(Cu) in the media significantly altered the cytotoxicity of biocompatible HAP(Cu). The osteogenic potential of HAP(Cu) was demonstrated by greater mineralization than that of pure HAP or the control. HAP(Cu) showed higher osteogenic gene expression than pure HAP and the control, indicating its stronger osteogenic potential. Furthermore, we assessed the effects of sample-treated macrophage-derived conditioned medium (CM) on hBMSCs' osteogenesis. CM-treated HAP(Cu) demonstrated a significantly higher osteogenic potential vis-à-vis pure HAP(Cu). These findings revealed that HAP(Cu) with CM significantly improved osteogenesis in hBMSCs and can be explored as a bone graft in bone tissue engineering.

Machine learning-assisted pattern recognition and imaging of multiplexed cancer cells via a porphyrin-embedded dendrimer array.

Early cancer detection plays a vital role in improving the survival rate of cancer patients, underscoring the importance of developing cancer detection methods. However, it is a great challenge to achieve simple, rapid, and accurate methods for simultaneously discerning various cancers. Herein we developed a 5-element porphyrin-embedded dendrimer-based sensor array, targeting the parallel discrimination of multiple cancers. The porphyrin-embedded dendrimers were modified with various functional groups to generate differentiated interactions with diverse cancer cells, which has been validated by fluorescence responses and laser confocal microscopy imaging. The dual-channel, five-element array, featuring ten signal outputs, achieved 100% accuracy in distinguishing between one human normal cell and six human cancerous cells, as well as in differentiating among mixed cells. Moreover, the screen 6-channel array can accurately distinguish 9 cells from mice and humans in minutes through optimization by multiple machine learning algorithms, including two normal cells and 7 cancerous cells with only 1000 cells, highlighting the significant potential of a porphyrin-embedded dendrimer-based parallel discriminating platform in early cancer diagnosis.

P-type doping in edge-enriched MoS2-x nanostructures via RF-generated nitrogen plasma.

In this work, we report an intuitive magnetron sputtering technique for the synthesis of vertically aligned MoS2 (v-MS) nanostructures. The morphology and orientation of the as-synthesized nanostructures can be modified by altering the parameters of the sputtering process. This work emphasizes the versatility of magnetron sputtering to synthesize edge-enriched vertically aligned 2D nanostructures. These structures have diverse applications, such as those in optoelectronics, hydrogen evolution, sensing, energy storage and catalysis. The vertically aligned nanostructure of MoS2 was confirmed using the field emission scanning electron microscopy and Raman spectroscopy techniques. Furthermore, we studied the plasma-based nitrogen doping process with minimal damage for introducing nitrogen atoms into 2D nanomaterials. A plasma discharged into a nitrogen environment, assisted by a simple radio frequency (RF) power supply, was employed for p-type doping in v-MS. The successful doping of nitrogen was investigated by Raman spectroscopy and X-ray photoelectron spectroscopy. Atomic force microscopy images confirmed the little surface damage resulting from the nitrogen doping technique. The change in work function resulting from doping was examined by Kelvin probe force microscopy and ultraviolet photoelectron spectroscopy. Optical emission spectroscopy (OES) study revealed the role of nitrogen plasma ions in doping with minimal surface damaging. This work demonstrates the effective alteration of the work function of the MoS2 nanomaterial via plasma treatment.

Vascularized tumor on a microfluidic chip to study mechanisms promoting tumor neovascularization and vascular targeted therapies.

The cascade of events leading to tumor formation includes induction of a tumor supporting neovasculature, as a primary hallmark of cancer. Developing vasculature is difficult to evaluate in vivo but can be captured using microfluidic chip technology and patient derived cells. Herein, we established an on chip approach to investigate the mechanisms promoting tumor vascularization and vascular targeted therapies via co-culture of cancer spheroids and endothelial cells in a three dimensional environment. Methods: We investigated both, tumor neovascularization and therapy, via co-culture of human derived endothelial cells and adjacently localized metastatic renal cell carcinoma spheroids on a commercially available microfluidic chip system. Metastatic renal cell carcinoma spheroids adjacent to primary vessels model tumor, and induce vessels to sprout neovasculature towards the tumor. We monitored real time changes in vessel formation, probed the interactions of tumor and endothelial cells, and evaluated the role of important effectors in tumor vasculature. In addition to wild type endothelial cells, we evaluated endothelial cells that overexpress Prostate Specific Membrane Antigen (PSMA), that has emerged as a marker of tumor associated neovasculature. We characterized the process of neovascularization on the microfluidic chip stimulated by enhanced culture medium and the investigated metastatic renal cell carcinomas, and assessed endothelial cells responses to vascular targeted therapy with bevacizumab via confocal microscopy imaging. To emphasize the potential clinical relevance of metastatic renal cell carcinomas on chip, we compared therapy with bevacizumab on chip with an in vivo model of the same tumor. Results: Our model permitted real-time, high-resolution observation and assessment of tumor-induced angiogenesis, where endothelial cells sprouted towards the tumor and mimicked a vascular network. Bevacizumab, an antiangiogenic agent, disrupted interactions between vessels and tumors, destroying the vascular network. The on chip approach enabled assessment of endothelial cell biology, vessel's functionality, drug delivery, and molecular expression of PSMA. Conclusion: Observations in the vascularized tumor on chip permitted direct and conclusive quantification of vascular targeted therapies in weeks as opposed to months in a comparable animal model, and bridged the gap between in vitro and in vivo models.

3D STED Imaging of Isolated Arabidopsis thaliana Nuclei.

Microscopy imaging of chromatin offers valuable insights into its spatial organization in the nucleus, a novel epigenetic dimension influencing the genome's functions. Particularly, visualization at the nanoscale in single cells is uniquely complementary to molecular profiling methods averaging chromatin configuration and composition over thousands of cells. How are chromatin and chromosomal domains distributed in relation to gene expression? How variable are these configurations? How do chromatin domains evolve in structure, composition, and distribution during cellular differentiation or cellular responses to environmental stimuli? Super-resolution microscopy techniques, like stimulated emission depletion (STED), are key in answering such questions. However, such imaging techniques are not often used in the field of plant cell biology compared to mammalian counterparts, which has greatly advanced our understanding of the 3D principles in genome organization. In an effort to bridge this gap, we provide a clear guide for isolating, embedding, immunostaining, and STED imaging intact leaf nuclei from Arabidopsis thaliana in 3D.

Portfolio of colloidally stable gold-gold sulfide nanoparticles and their use in broad-band photoacoustic imaging.

There is an increasing interest in non-invasive photoacoustic imaging and hence demand for non-toxic, stable, optical solid absorbers, particularly in the visible and near-infrared regions enabling deep tissue penetration. The most popular gold nanorods (GNR) suffer from cumbersome synthesis with poor reproducibility and stability under moderate laser exposure. Recently, a new class of nanoparticle, gold-gold sulfide (GGS), was recognized to have strong NIR absorption but lack colloidal stability. Here, we successfully synthesized a portfolio of aqueous GGS nanoparticles (NP) with excellent stability through a one-step, reproducible synthesis: Anionic, cationic, and protein-coated GGS NPs were obtained by using 3-mercaptopropionic acid (3MPA), branched poly(ethyleneimine) (bPEI) and bovine serum albumin (BSA) as a coating. All GGS NPs comprise small (<10 nm) and large anisotropic (>30 nm) morphologies and display two absorption bands centered at 530-540 nm and 800-900 nm. The photoacoustic activity (PA) of GGS NPs in solution at the visible (532 nm) and NIR (800 nm) region is similar and independent of the coating. Remarkably, they outperformed the spherical gold NPs and performed comparable to GNRs. In vitro PA microscopy images recorded with visible and NIR lasers revealed that GGS NPs are successfully internalized by triple-negative MDA-MB-231 breast cancer cells, used for the proof of principle. A coating-dependent intracellular PA signal in favor of GGS-3MPA was observed. The weakest signal was obtained with the GGS-BSA, indicating a low cellular uptake. These stable, aqueous GGS NPs emerge as promising candidates for broad-band PAI and further biomedical applications.

Microfluidics to Follow Spatiotemporal Dynamics at the Nucleo-Cytoplasmic Interface During Plant Root Growth.

Nuclear dynamics refers to global/local changes in the molecular and spatial organization of genomic DNA that can occur during development or in response to environmental stress signals and eventually impact genomic functions. In plants, nuclear dynamics relies notably on the connection of the nucleus with the cytoskeleton during development. It orchestrates genomic functions in response to developmental and environmental cues. This is particularly true in the plant root system, which is constantly exposed to a wide range of internal and external stimuli. Currently, studying nuclear dynamics in a growing root is challenging due to limitations regarding real-time imaging for quantitative analyses under controlled conditions. Microfluidic systems for plant cell studies are valuable analytical tools that provide precise control of culture conditions together with live-imaging capabilities at high temporal and spatial resolutions. Herein, we describe a microfluidic platform to unravel dynamically and noninvasively nuclear organization in the seedling root system exposed to various treatments. As exemplified here, our microfluidic platform can be conveniently used for real-time microscopy imaging and quantitative analysis of fine nuclear morphological changes upon modifying cytoskeleton dynamics. Importantly, our system can be applied to a wide variety of microscopic means including high-resolution microscopy to investigate diverse subcellular compartments or nuclear domains in Arabidopsis thaliana roots.

Structure and Oxygen Saturation Recovery of Sparse Photoacoustic Microscopy Images by Deep Learning

Structure and Oxygen Saturation Recovery of Sparse Photoacoustic Microscopy Images by Deep Learning

Structure, Morphology, DC-Electrical and Dielectric Characteristics of Chromium(III) Substituted Co-Li Ferrite Nanoparticles

In this study, a detailed analysis of the lattice structure, micro-structural features, DC-electrical properties and dielectric characteristics of Cr3+-substituted cobalt-lithium-based ferrite oxide nanoparticles (CoLiFCr NPs) synthesized using a sol-gel method enhanced by synergistic sol-gel auto-combustion is presented. Citric acid monohydrate (C6H8O7·H2O) was utilized as a chelating agent, maintaining a metal nitrate to citrate ratio of 1:3. Substituting Cr3+ in Co-Li ferrite significantly alters its crystal structure, morphological, DC-electrical and dielectric characteristics. The X-ray diffraction (XRD) analysis confirmed the crystalline formation of Co0.8Li0.4Fe2-xCrxO4 nanoparticles (where x = 0.0, 0.2, 0.4 and 0.6); exhibiting the single-phase cubic structure characterized by a spinel configuration, falling under the space group Fd-3mO7h. The lattice constant a for CoLiFCr NPs (x = 0) was measured at 8.338 ± 0.002 Å, which decreased to 8.291 ± 0.002 Å upon Cr substitution (x = 0.6), as confirmed by Cohen’s analytical graphs. The crystallite size (D), determined using the Debye-Scherrer’s formula, ranged from around 18.9 to 29.74 nm. Peak broadening in CoLiFCr NPs was further examined through Williamson-Hall and size strain analyses. The FTIR spectra of CoLiFCr nanoparticles revealed the presence of metal-oxygen (M-O) bonds typical of spinel structures, featuring significant peaks at 443 cm–1 and 537 cm–1. High-resolution transmission electron microscopy (HR-TEM) images showed the single-crystal CoLiFCr NPs with nearly spherical morphologies. The study of optical properties was conducted using UV-visible spectroscopy. The nanoparticles with x = 0.2 displayed high ε' values at 50 Hz, indicating strong polarization capabilities, while those with x = 0.6 exhibited a decrease possibly linked to structural changes affecting polarization. The DC resistivity of CoLiFCr nanoparticles was investigated to understand their electrical behaviour highlighting the influence of substitution of Cr3+ on conductivity.

Physicochemical Properties of Biochar Prepared from Guinea Corn Straw as a Function of Different Pyrolysis Temperatures

The present study examined the effect of pyrolysis temperature on the physicochemical properties of biochar produced from guinea corn straws at different temperatures (300-600℃). However, the produced biochars were designated as BCG-300, BCG-400, BCG-500 and BCG-600, respectively. The produced biochar’s were characterized by different analytical techniques. These include; the proximate and elemental analyses, morphological, crystallographic, functional groups and specific surface area analyses were investigated using elemental analyzer, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller (BET), respectively. The results indicated that. increasing pyrolysis temperature increased the content of fixed carbon (C), the C content, the total content of K, Ca, and Fe, as well as the cation exchange capacity (CEC), pH, and EC. While the yield, the content of volatile matter O and H, and the ratios of O/C and H/C decreased. Additionally, at higher pyrolysis temperature, the BET surface area and pore volume increased with increased in temperature, typically due to the increase of the micropore surface area and micropore volume. Furthermore, the data of Fourier transformation infrared showed that at higher pyrolysis temperature, the biochar aromaticity increased and decreased in polarity. Similarly, the crystalline mineral components increased with pyrolysis temperatures due to the cellulose loss, as indicated by X-ray diffraction analysis and scanning electron microscope images. Hence, pyrolysis temperature has a strong effect on biochar properties, and therefore biochars can be produced by changing pyrolysis temperature in order to meet their applications, such as carbon sequestration, greenhouse gas mitigation and as an adsorbent for organic and inorganic contaminants when applied to the environment etc.