Rod Morphology Research Articles

Bioinformatic analysis reveals the association between bacterial morphology and antibiotic resistance using light microscopy with deep learning.

Although it is well known that the morphology of Gram-negative rods changes on exposure to antibiotics, the morphology of antibiotic-resistant bacteria in the absence of antibiotics has not been widely investigated. Here, we studied the morphologies of 10 antibiotic-resistant strains of Escherichia coli and used bioinformatics tools to classify the resistant cells under light microscopy in the absence of antibiotics. The antibiotic-resistant strains showed differences in morphology from the sensitive parental strain, and the differences were most prominent in the quinolone-and β-lactam-resistant bacteria. A cluster analysis revealed increased proportions of fatter or shorter cells in the antibiotic-resistant strains. A correlation analysis of morphological features and gene expression suggested that genes related to energy metabolism and antibiotic resistance were highly correlated with the morphological characteristics of the resistant strains. Our newly proposed deep learning method for single-cell classification achieved a high level of performance in classifying quinolone-and β-lactam-resistant strains.

Microstructure and properties of Cu-doped β-Ga2O3 rod prepared with liquid metallic gallium

One-dimensional β-Ga2O3 is expected for potential applications in electronics, sensors, and optoelectronics. Gallium hydroxide (GaO(OH)) with different Cu doping was prepared via the hydrothermal method using liquid metallic gallium and copper chloride dihydrate (CuCl2·2H2O) as the starting materials. The material was then transformed to β-Ga2O3 after calcination at 800 °C. SEM images reveal that the obtained powders are well dispersed and have a uniform rod morphology with a length of 13–14 μm and a width of approximately 500 nm. The addition of Cu ion significantly improves the surface morphology of the rod and effectively inhibits the generation of intrinsic oxygen vacancies. And the relative Fermi energy level of Cu-doped β-Ga2O3 undergoes a notable shift from 2.81 eV to 1.25 eV, suggesting the formation of p-type conductivity. Meanwhile, the PL spectra of the Cu-doped samples exhibit emission peaks in the red wavelength range, which is expected for new applications.

Controllable preparation and morphology regulation of nanocelluloses from waste paper by a green hydrolysis method

This study focused on the morphology regulation of nanocelluloses (NCs) aiming at preparing NCs with the controllable properties. NCs with rod-shaped, spherical, and rod-shaped and spherical composite structures were prepared from waste paper by a green enzymatic hydrolysis. The critical enzyme concentration for the transition of NCs from one morphology to another was explored. Several analytical methods, including TGA, XRD, SEM, TEM, DSC and WCA, were employed to characterize the prepared NCs. The results showed that with the cellulase enzyme concentration lower than 6 μ/ml or higher than 30 μ/ml, the prepared NCs had a single rod-shaped or spherical structure. When the cellulase concentration was between 6 and 30 μ/ml, the prepared NCs had a composite morphology of rods and spheres. Besides, NCs with a composite morphology dominated by rod-like or spherical structures had a higher thermal stability. Moreover, NCs prepared with cellulase enzyme concentration of 6 and 35 μ/ml had the highest and lowest crystallinity of 81.7 % and 59.3 %, respectively. Hence, this work achieved the morphology and property regulation of NCs by a green method which expanded the application scope of NCs and realized the high value utilization of waste paper.

Impact of morphology and crystalline structure over the Zn2+ ions storage in two-step solvothermal derived VO2

Aqueous rechargeable zinc ion batteries (ARZIBs) represent a cheaper and more environmentally friendly alternative to lithium-ion batteries (LIBs) in energy storage systems. Vanadium oxide is one of the most attractive materials to be used as a cathode in ARZIBs because it has multiple oxidation states that grant high specific capacity. This work employed an alternative synthetic route to obtain VO2 with varied morphology and structural properties utilizing vanadyl acetylacetonate as a precursor by tuning the temperature during two-step solvothermal/hydrothermal treatment. When highly crystalline VO2 (B) with rod morphology is obtained, the electrode exhibits the best electrochemical response, with the most significant contribution of surface-confined redox processes to the charge stored. The ARZIB assembled with VO2 rod showed an initial capacity of up to ∼300 mA h g−1 (2.4 mA h cm−2) at 0.1 A g−1, delivering a specific energy of up to 168 W h kg−1 at a specific power of 65 W kg−1. It exhibits outstanding stability after 2000 GCD cycles at 2.5 A g−1. Ex-situ structural and spectroscopic characterization showed that Zn2+ storage causes an expansion and contraction of the lattice without evidence of crystalline phase transformations.

A novel zingerone-loaded zinc MOF coated by niosome nanocomposites to enhance antimicrobial properties and apoptosis in breast cancer cells

Breast cancer (BC) is a prevalent malignancy among women, presenting significant health risks. The development of targeted smart drug delivery has greatly enhanced tumor therapy and antibacterial treatments. In this study, we fabricated a novel Zn-metal organic framework (Zn-MOF) at the nanoscale using an oil bath technique and loaded it with zingerone (ZG) and coated with niosomes (Nio) to form ZG-Zn-MOF@Nio, designed for both anti-microbial and anticancer purposes. We investigated the anti-microbial activity by assessing the minimum inhibitory concentration and zone of inhibition by zingerone, Zn-MOF, and ZG-Zn-MOF@Nio. Scanning electron microscopy (SEM) analysis revealed that the synthesized ZG-Zn-MOF@Nio exhibited well-defined rod and cilia-like morphology. Transmission electron microscopy (TEM) images showed ZG-Zn-MOF@Nio nanoparticles (NPs) with a spherical-like shape and an average diameter of 0.34 µm and a zeta potential of (+22 mV). The encapsulation efficiency of zingerone into Zn-MOF was up to 92.56 %, with a loading capacity of 11.55 % (*P<0.05). Four kinetic models were used to analyze the release mechanism of zingerone at pH 6.5, with the zero-order model showing an excellent fit (R2 = 0.9985, *P<0.05). Additionally, the minimum inhibitory concentration of synthesized zingerone, Zn-MOF, and ZG-Zn-MOF@Nio NPs were tested against Gram-positive Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aures), as well as the gram-negative strains Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In vitro test revealed that the minimum inhibitory concentration of ZG-Zn-MOF@Nio was 31.25 μg/mL against S. aures and B. subtilis, and 62.5 μg/mL against P. aeruginosa and E.coli were. The MCF-7 cell line was utilized as in-vitro model. The MTT assay demonstrated significant cytotoxicity of ZG-Zn-MOF@Nio against MCF-7 cells, with an IC50 values of 46.2 µg/mL, inducing apoptosis in 94.8 % of the cells.

Investigation of the Electrochemical Behavior of CuO-NiO-Co3O4 Nanocomposites for Enhanced Supercapacitor Applications.

In the present study, composites incorporating NiO-Co3O4 (NC) and CuO-NiO-Co3O4 (CNC) as active electrode materials were produced through the hydrothermal method and their performance was investigated systematically. The composition, formation, and nanocomposite structure of the fabricated material were characterized by XRD, FTIR, and UV-Vis. The FE-SEM analysis revealed the presence of rod and spherical mixed morphologies. The prepared NC and CNC samples were utilized as supercapacitor electrodes, demonstrating specific capacitances of 262 Fg-1 at a current density of 1 Ag-1. Interestingly, the CNC composite displayed a notable long-term cyclic stability 84.9%, which was observed even after 5000 charge-discharge cycles. The exceptional electrochemical properties observed can be accredited to the harmonious effects of copper oxide addition, the hollow structure, and various metal oxides. This approach holds promise for the development of supercapacitor electrodes. These findings collectively indicate that the hydrothermally synthesized NC and CNC nanocomposites exhibit potential as high-performance electrodes for supercapacitor applications.

Synergistically enhanced electromagnetic absorption in barium ferrite/hollow carbon spheres/epoxy composites

The ongoing technological advancements have emphasized the importance of absorbent coatings, which are essential for effectively absorbing electromagnetic waves across various industries, including electronics, healthcare, and security systems. In this research, barium ferrite particles and hollow spherical carbon particles have been synthesized to investigate the synergistic effect of different compounds in absorbing electromagnetic waves in the epoxy coating. The barium ferrite particles were synthesized in two distinctive rod and spherical morphologies at 600 and 900 °C, employing the sol-gel technique. Also, hollow spherical carbon particles were synthesized. Synthesized particles were analyzed structurally and chemically with an X-ray Powder Diffraction, Fourier infrared spectrometer, vibrating‐sample magnetometer, field emission Scanning Electron, and Raman spectroscopy.The absorption characteristics of a coating that contains rod and spherical morphologies of barium ferrite and hollow spherical carbon particles can be adjusted by controlling the amounts of synthetic compounds in the 8–12 GHz range. The results indicate that combining rod-shaped barium ferrite particles (900 °C) and hollow spherical carbon particles in a thin epoxy coating improves impedance matching and wave attenuation. Notably, when the epoxy coating is 1.5–2 mm thick and contains 20 % rod-shaped barium ferrite particles (900 °C) and 1 % hollow spherical carbon particles, reflection loss values of < -20 dB are observed at frequencies of 10–12 GHz.

Perovskites synthesized by soft template-assisted hydrothermal method: A bibliometric analysis and new insights

Hydrothermal synthesis is a technique which enables preparing many perovskites with specific crystal structures, chemical compositions, and morphologies. Thus, a bibliometric analysis of 1087 articles from the Scopus database (1975–2023) related to the keywords “perovskites” and “hydrothermal synthesis” was conducted using the VOSviewer software program. The results of the bibliometric analysis showed that the 1087 articles have 23,286 citations. Materials Letters has the highest number of publications (2.85%) regarding the journals in which these articles are published. China has the highest number of publications (34.50%) and citations (33.56%) related to these articles. Regarding the institutions affiliated with these articles, Jilin University in China concentrates 5.34% of the publications and 6.08% of the citations. In terms of authors, Han, G. has the highest number of publications (2.02%). Finally, the top three keywords with the highest number of occurrences were “perovskite”, “hydrothermal synthesis” and “scanning electron microscopy”. Based on bibliometric analysis, LaNiO3 perovskites were chosen to evaluate the influence of hydrothermal synthesis parameters on their morphologies and, consequently, how these morphologies affect their applications. Thus, the temperature and time ranges used for the synthesis parameters were 160–230 °C and 6–48 h, respectively. Furthermore, the pH range used was 7.6–13, and the mineralizers used to adjust the pH were ammonia, potassium hydroxide, and sodium hydroxide. The temperature and time ranges used for the calcination parameters were 550–800 °C and 2–6 h, respectively. Additionally, LaNiO3 perovskites obtained sphere, cube, rod, disc, and hollow morphologies. The soft templates used to obtain these morphologies were glycine, glycerin, isopropanol, polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), citric acid, and urea. The specific surface areas of the perovskites varied between 5.2 and 35.8 m2 g−1. Finally, the most common application for LaNiO3 perovskites was the methane reforming for hydrogen production.

Regulating the partially mixed zone via post-weld heat treatment to enhance sulfide stress corrosion cracking resistance of the Inconel 625/X80 weld overlay

This paper investigated the effect of post-weld heat treatment (PWHT) on microstructure evolution and sulfide stress corrosion cracking (SSCC) behavior of the fusion boundary (FB) region of Inconel 625/X80 weld overlay, with a focus on the partially mixed zone (PMZ). Three heat treatment regimens were designed, namely 620 °C/10 h, 620 °C/20 h, and 670 °C/10 h, in which 620 °C/20 h was proved to be the optimal parameter. The 10-hour PWHT conditions might induce heterogeneous carbon distribution owing to insufficient tempering duration, exacerbating the hardness mismatch in the FB region and thus promoting the development of SSCC. Following the 620 °C/20 h treatment, most of the brittle phase with high hardness in the FB region was eliminated, reducing the nucleation site for SSCC. More importantly, martensite in the PMZ was transformed into austenite with rod morphology, while cementite adjacent to the PMZ might evolve into dispersed refined austenite. Austenite shows low hydrogen sensitivity, enhancing the SSCC resistance of the PMZ. On the other hand, the carbides in the X80 matrix might restrict the diffusion of hydrogen toward the PMZ, thereby reducing the susceptibility of the PMZ to SSCC.

Separation of uranium from lanthanides (La, Ce, Nd) and purification of waste salt via aluminum electrodes with different structures in LiCl-KCl eutectic

Aluminum is an ideal cathode material for the pyrochemical reprocessing of spent nuclear fuels. However, there is a lack of large-scale experiments to further assess its performance. Here we designed several Al electrodes with sheet, rod, and porous morphologies, and employed them in separating actinides (An) from lanthanides (Ln) and purifying the waste salts in about 500 g of LiCl-KCl eutectic melt at 773 K. By applying a constant potential of −1.2 V vs. Ag/AgCl, U can be separated from Ln (La, Ce, and Nd) by forming Al-U alloys consisting of Al3U and Al4U with high separation factors and current efficiency. Among all Al electrodes used in our experiments, the porous-shaped ones show the fastest electrochemical reaction rate, and hence only 56 h were required to achieve the separation. Subsequently, the purification of the waste salts from U-Ln separation was conducted via constant potential electrolysis at −1.5 V vs. Ag/AgCl on porous-shaped Al electrodes. About 99.9 % of Ln was extracted via forming Al-Ln alloys, leaving a purified electrolyte that can be reused. In all, about 17 g of U metals and 1 kg of waste salts were successfully reprocessed in our large-scale experiments, which envisions the feasibility of applying Al electrodes in engineering-scale pyrochemical reprocessing.

Tuning Textural Properties by Changing the Morphology of SBA-15 Mesoporous Materials.

Changing the morphology is an excellent option for altering the textural parameters of SBA-15 materials. This study provides a guide on how the properties of mesoporous structures behave according to their morphology and their contribution to thermal stability. The objective of this work was to synthesize different morphologies (spherical, hexagonal prisms, rice-like grains, rods, and fibers) of SBA-15 materials and evaluate the existing textural changes. The materials were synthesized by varying the temperature of the synthesis gel from 25 °C to 55 °C, with stirring at 300 or 500 rpm. The results of X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption and desorption, and scanning electron microscopy were evaluated. Thermal stability tests were also conducted in an inert atmosphere. The materials were successfully synthesized, and it was observed that they all exhibited different characteristics, such as their ordering, interplanar distance, mesoporous parameter, specific surface area, micropore and mesopore volumes, external mesoporous area, and wall thickness. They also presented different thermal stabilities. The rice grain morphology had the highest specific surface area (908.8 cm2/g) and the best thermal stability, while the rod morphology had the best pore diameter (7.7 nm) and microporous volume (0.078 cm3/g).

Impact of copper and cobalt-based metal-organic framework materials on the performance and stability of hole-transfer layer (HTL)-free perovskite solar cells and carbon-based

This article investigates the impact of metal-organic frameworks (MOFs) on the performance and stability of perovskite solar cells (PSCs), specifically focusing on the type of metal and the morphology of the MOF. Two types of MOFs, copper-benzene-1,3,5-tricarboxylate (Cu-BTC MOF) with spherical morphology and cobalt-benzene-1,3,5-tricarboxylate (Co-BTC MOF) with rod morphology, are synthesized and spin-coated on TiO2 substrates to form FTO/TiO2/MOF/CH3NH3PbI3/C-paste PSCs. The morphology and size of the MOFs are characterized by scanning electron microscopy (SEM), and the crystallinity and residual PbI2 of the perovskite films are analyzed by X-ray diffraction (XRD). The results show that the Co-BTC MOF PSC exhibits the highest power conversion efficiency (PCE) of 10.4% and the best stability, retaining 82% of its initial PCE after 264 h of storage in ambient air. The improved performance and stability are attributed to the enhanced crystallinity and reduced residual PbI2 of the perovskite film after Co-BTC MOF modification. The paper showcases the immense potential of MOF-based interlayers to revolutionize PSC technology, offering a path toward next-generation solar cells with enhanced performance and longevity.

Impact of Ceria Support Morphology on Au Single‐Atom Catalysts for Benzyl Alcohol Selective Oxidation

AbstractAlcohol oxidations are a key industrial chemical transformation, with aldehydes and ketones finding use in an array of applications. Nobel metals are known for their activity towards this chemoselective transformation, however, sustainable catalyst synthesis requires optimal utilisation of these scarce elements. Here, we report Au catalytic systems based on the deposition of isolated Au sites on different morphologies of ceria in which different surface facets of the support are exposed. Through tailoring the support morphology and from extensive catalyst characterisation, it is shown that the exposed facet is critical for controlling the formation (or not) of isolated Au sites. Both the 110 and 111 facets are capable of this feat, yielding single‐atom sites for rod, octahedron, and polyhedron morphologies. In contrast, the 100 facet is not, resulting in Au nanoparticles on cubic ceria. This dictation over Au species is critical to benzyl alcohol oxidation capacity at mild conditions and in the absence of a soluble base, with only single‐atom catalyst (SAC) systems demonstrating activity. Furthermore, the exposed surface facet also governs the degree of surface oxygen vacancies, which is critical to catalyst activity due to their control over substrate adsorption strength, as revealed through T1/T2 NMR relaxation measurements.

Mechanically suitable and osteoinductive 3D-printed composite scaffolds with hydroxyapatite nanoparticles having diverse morphologies for bone tissue engineering.

The challenge of integrating hydroxyapatite nanoparticles (nHAp) with polymers is hindered by the conflict between the hydrophilic and hygroscopic properties of nHAp and the hydrophobic properties of polymers. This conflict particularly affects the materials when calcium phosphates, including nHAp, are used as a filler in composites in thermal processing applications such as 3D printing with fused filament fabrication (FFF). To overcome this, we propose a one-step surface modification of nHAp with calcium stearate monolayer. Moreover, to build the scaffold with suitable mechanical strength, we tested the addition of nHAp with diverse morphology-spherical, plate- and rod-like nanoparticles. Our analysis showed that the composite of polycaprolactone (PCL) reinforced with nHAp with rod and plate morphologies modified with calcium stearate monolayer exhibited a significant increase in compressive strength. However, composites with spherical nHAp added to PCL showed a significant reduction in compressive modulus and compressive strength, but both parameters were within the applicability range of hard tissue scaffolds. None of the tested composite scaffolds showed cytotoxicity in L929 murine fibroblasts or MG-63 human osteoblast-like cells, supporting the proliferation of the latter. Additionally, PCL/nHAp scaffolds reinforced with spherical nHAp caused osteoactivation of bone marrow human mesenchymal stem cells, as indicated by alkaline phosphatase activity and COL1, RUNX2, and BGLAP expression. These results suggest that the calcium stearate monolayer on the surface of the nHAp particles allows the production of polymer/nHAp composites suitable for hard tissue engineering and personalized implant production in 3D printing using the FFF technique.

Vision-Based Estimation of Force Balance of Near-Suspended Melt Pool for Drooping and Collapsing Prediction.

Wire-arc additive manufacturing (WAAM) is favored by the industry for its high material utilization rate and low cost. However, wire-arc additive manufacturing of lattice structures faces problems with forming accuracy such as broken rod and surface morphology defects, which cannot meet the industrial demand. This article innovatively combines the melt pool stress theory with visual perception algorithms to visually study the force balance of the near-suspended melt pool to predict the state of the melt pool. First, the method for melt pool segmentation was studied. The results show that the optimized U-net achieved high accuracy in melt pool segmentation tasks, with accuracies of 98.18%, MIOU 96.64%, and Recall 98.34%. In addition, a method for estimating melt pool force balance and predicting normal, sagging, and collapsing states of the melt pool is proposed. By combining experimental testing with computer vision technology, an analysis of the force balance of the melt pool during the inclined rod forming process was conducted, showing a prediction rate as high as 90% for the testing set. By using this method, monitoring and predicting the state of the melt pool is achieved, preemptively avoiding issues of broken rods during the printing process. This approach can effectively assist in adjusting process parameters and improving welding quality. The application of this method will further promote the development of intelligent unmanned WAAM and provide some references for the development of artificial intelligence monitoring systems in the manufacturing field.

A study on the kinetic arrest of magnetic phases in nanostructured Nd0.6Sr0.4MnO3 thin films

The Nd0.6Sr0.4MnO3 (NSMO) manganite system exhibits a phase transition from paramagnetic insulating (PMI) to ferromagnetic metallic (FMM) state around its Curie temperature T C = 270 K (bulk). The morphology-driven changes in the kinetically arrested magnetic phases in NSMO thin films with granular and crossed-nano-rod-type morphology are studied. The manganite thin films at low temperatures possess a magnetic glassy state arising from the coexistence of the high-temperature PMI and the low-temperature FMM phases. The extent of kinetic arrest and its relaxation was studied using the ‘cooling and heating in unequal field (CHUF)’ protocol in magnetic and magnetotransport investigations. The sample with rod morphology showed a large extent of phase coexistence compared to the granular sample. Further, with a field-cooling protocol, time-evolution studies were carried out to understand the relaxation of arrested magnetic phases across these morphologically distinct thin films. The results on the devitrification of the arrested magnetic state are interpreted from the point of view of homogeneous and heterogeneous nucleation of the ferromagnetic phase in the paramagnetic matrix with respect to temperature.

A Comprehensive Study on Microstructure and Wear Behavior of Nano-WC Reinforced Ni60 Laser Coating on 17-4PH Stainless Steel

The surface of 17-4PH martensitic stainless steel was laser-cladded with Ni60 and Ni60+nano-WC composites and a comprehensive investigation was conducted of the microstructure and wear mechanism. The findings demonstrate that despite the added nano-WC particles being fused and dissolved during laser cladding, they still lead to a reduction in grain size and a decrease in crystallographic orientation strength. Furthermore, the dissolution of nano-WC makes the lamellar M23C6 carbides transform into a rod or block morphology, and leads to the CrB borides becoming finer and more evenly dispersed. This microstructural evolution resulted in a uniform increase in hardness and wear resistance, effectively preventing crack formation. When the nano-WC addition increased to 20 wt.%, there was a 27.12% increase in microhardness and an 85.19% decrease in volume wear rate compared to that of the pure Ni60 coating. Through analysis of the microstructure and topography of wear traces, it can be inferred that as the nano-WC addition increased from 0 wt.% up to 20 wt.%, there was a gradual transition from two-body abrasive wear to three-body abrasive wear, ultimately resulting in adherent wear.

Rapid Deposition of the Biomimetic Hydroxyapatite-Polydopamine-Amino Acid Composite Layers onto the Natural Enamel.

In this work, we developed a technology that enables rapid deposition of biomimetic composite films onto natural enamel slices (known as biotemplates). These films are composed of polydopamine (PDA) and nanocrystalline carbonate-substituted hydroxyapatite (nano-cHAp) that have been functionalized with amino acid l-Arginine. We utilized atomic force microscopy (AFM) and scattering scanning near-field optical microscopy (s-SNOM) combined with infrared (IR) synchrotron to achieve nanoscale spatial resolution for both IR absorption and topography analyses. This combined analytical modality allowed us to understand how morphology connects to local changes in the chemical environment on the biotemplate surface during the deposition of the bioinspired coating. Our findings revealed that when using the proposed technology and after the deposition of the first PDA layer, the film formed on the enamel surface nearly covers the entire surface of the specimen whose thickness is larger on the surface of the emerging enamel prisms. Calculation of the crystallinity index for the biomimetic layer showed a multiple increase compared with natural enamel. This indicates regular and dense aggregation of nano-cHAp into larger crystals, imitating the morphology of natural enamel rods. The microhardness of the formed PDA-based biomimetic layer mineralized with nano-cHAp functionalized with amino acid l-Arginine deposited on natural enamel was practically the same as that of natural enamel. The characterization of nano-cHAp-amino acid-PDA layers using IR and Raman microspectroscopy showed that l-arginine acts as a conjunction agent in the formation of mineralized biomimetic composite coatings. The uniformity of the mechanisms of PDA layer formation under different deposition conditions and substrate types allows for the formation of coatings regardless of the macro- and micromorphology of the template. Therefore, the results obtained in this work have a high potential for future clinical applications in dental practice.

First Report of Aeromonas schubertii Infection in Striped Snakehead Channa striata (Bloch, 1793) Fingerlings in Malaysia

Striped snakehead fingerlings Channa striata reared in a concrete pond with size 13.5 m3 (3 m ´ 3 m ´ 1.5 m) in a hatchery farm, in Labu, Negeri Sembilan, Malaysia had more than 70% mortality. The pond contained 1500 fingerlings of 5–7 cm in total length (TL). The purpose of this study was to investigate the high mortality event on the farm as part of a veterinary diagnostics service. Clinical signs observed were skin discoloration, lethargy, and anorexia. Necropsy was performed in 10 fish with gross lesions of 1–2 mm and multiple whitish nodules in the abdominal organs and most notably in the liver, and kidney. Following necropsy, bacteriology samples from the kidney and liver were inoculated onto Tryptic Soy Agar (TSA) and Blood Agar (BA). Pure colonies were observed and were Gram-negative with short rod morphology. The full-length 16S rRNA gene was amplified from the pure colonies followed by sequencing using the Nanopore MinION™ (Oxford Nanopore, UK). The isolated strain was identified as Aeromonas schubertii based on the assembled 16S rRNA sequence showing nucleotide identity of 99.73% (top hit) to A. schubertii (GenBank Accession: NR_037014.2) while only a nucleotide identity of 97.55% was observed against Aeromonas hydrophila (GenBank Accession: NR_119190.1-), respectively. Histopathological examination from the liver, kidney, spleen, and intestine revealed granulomatous nephritis, and degeneration of tubular epithelium, with granulomatous hepatitis, splenitis, and enteritis. The prognosis of this case was grave. No treatment was given as the owner had decided to dispose of all current stock. This is the first A. schubertii infection in C. striata described in Malaysia. The findings of the present study may serve as a reference for similar cases in C. striata in the future so rapid diagnosis and treatment can be made if required.

Negative permittivity and permeability behaviour of SrFe12O19/rGO metacomposite for microwave absorption in 2–18 GHz range

Double-negative performance has played a significant role in electronic applications owing to its both permeability and permittivity negative values. Microwave absorption material has a substantial role in electromagnetic shielding, radar absorption, stealth applications, etc. Herein, a novel double-negative metacomposite, SrFe12O19/rGO, was designed by a simple one-pot hydrothermal method, and the microwave absorption properties of the material were studied in the microwave region from 2 to 18 GHz using VNA analysis. The structural and morphological studies were analysed using XRD, FT-IR, and SEM instrumentation techniques and the magnetic property of the material was studied using VSM analysis. Both studies confirmed the hard magnetic nature of the material. The particle sizes of SrFe12O19 and SrFe12O19/rGO measured from XRD are 55.60 nm and 41.55 nm, respectively. Hexagonal plate-like morphology were observed from FESEM images. The coercivity of SrFe12O19/rGO increased, and the magnetocrystalline anisotropy was changed due to the decrease in particle size. The magnetic saturation value decreases due to the presence of non-magnetic rGO. The resultant SrFe12O19/rGO metacomposite shows negative permittivity and permeability values. The minimum reflection loss values observed for pure and rGO-decorated strontium ferrites are −28.49 dB at 7.76 GHz and −23.78 at 11.04 GHz, respectively. In addition to experimental results, simulation studies were also performed to study the reflection loss with matching thickness using a quarter wavelength mechanism. The results show that this composite can be employed as a left-handed metamaterial that finds applications in absorption, antennas, sensors, wireless power transfer systems, etc. The left-handed metamaterial can shift the frequency region from a lower to a higher frequency region. The rGO decorated metacomposite is a promising material for microwave absorption at higher frequency regions.