Electron Microscopy Studies Research Articles

Green Synthesis of Nanomaterials with Phytochemicals for Treating Multidrug Resistant Bacteria

The Bacteria with Multidrug resistance and Extreme drug resistance are increasing at a rapid rate. Various methods have been employed to combat drug resistant bacteria. Major classes of antibiotics aren’t effective against these bacteria. Alternative methods have been studied in recent years. Nanoparticles are used against multidrug resistant bacteria; The green synthesized nanoparticles are more reliable due to more shelf life and lesser toxicity relative to chemically synthesized nanoparticles. Multi drug resistant E. coli and Staphylococcus aureus was isolated from sewage samples. Green synthesized nanoparticles from various plants samples have been prepared with Zinc and Copper forming respective oxides with Neem, Nakara, Jatropha, Mango, Clove, Ginger, Cardamom, Cinnamon and Betel against multidrug resistant Escherichia coli and Staphylococcus aureus. Isolated E. coli was susceptible to Fluoroquinolone and Augmentin whereas S. aureus was susceptible to vancomycin. Green synthesized nanoparticles had more antimicrobial activity against E. coli and S. aureus than chemically synthesized nanoparticles and plant extracts. Green synthesized Nakara CuO nano particles had inhibition zone of 31 ±0.6mm and 30 ±0.7mm for E. coli and S. aureus respectively, ZnO nano particles of Nakara had 25 ±0.6mm inhibition zone for E. coli and S. aureus. Green synthesized Jatropha CuO nano particles had inhibition zone of 26 ±0.5 and 26 ±0.4mm for E. coli and S. aureus. ZnO nano particles of Jatropha had 31±0.7mm and 30±0.7mm inhibition zone for E. coli and S. aureus respectively. The Scanning electron microscopy studies revealed 26nm Jatropha ZnO and 25nm Nakara CuO nanoparticles. Nano materials were found to be non-toxic in cell line studies. The present study concludes to study the impact of green synthesized nanoparticles as an alternative to antibiotics to combat multidrug resistant bacteria.

Electron microscopy study of left ventricular cardiomyocytes in adult rats born preterm

BACKGROUND: Preterm birth is a risk factor for the early development of cardiovascular diseases. Thus far, based on the results of clinical studies, the ultrastructural features of cardiomyocytes in adolescents and adults born prematurely can be identified. Thus, experiments aimed at studying the effects of preterm birth on the ultrastructure of cardiomyocytes in the late postnatal period of ontogenesis are relevant. AIM: To identify the ultrastructural features of left ventricular cardiomyocytes in preterm adult rats. MATERIALS AND METHODS: The study was conducted on full-term (n=4, pregnancy duration 22 days) and preterm (n=4, pregnancy duration 21 days) male Wistar rats. Preterm labor was induced by mifepristone injection to pregnant rats. Preterm and full-term offspring were removed from the experiment on day 180 of the postnatal period of ontogenesis. Fragments of the left ventricle of the heart of preterm and full-term rats were used for the ultrastructural studies of the cardiomyocytes (electron transmission microscopy). Electron microphotographs of longitudinal sections of contractile cardiomyocytes were used to determine the relative areas of the nucleus, cytoplasm, myofibrils, and mitochondria. RESULTS: The structure of the cardiomyocytes of preterm and full-term rats on postnatal day 180 was fundamentally similar. However, the relative area of the nuclei of cardiomyocytes in preterm rats was lower (p=0.02), and the relative area of the cytoplasm was higher (p=0.02) than that in full-term animals. Exclusively, in the cytoplasm of preterm rats, perinuclear swelling of the cytoplasm, thinning of myofibrils, and signs of mitochondrial damage, such as destruction of mitochondrial membranes, concentric organization of mitochondrial cristae, and dissociation of mitochondrial clusters, were observed. CONCLUSION: Preterm birth has chronic negative effects on the ultrastructure of cardiomyocytes. The observed ultrastructural changes lead to the disruption of energy production in the cardiomyocytes in the late postnatal period of ontogenesis of preterm rats.

An alternative approach in the synthesis of strontium-hydroxyapatite and strontium hydroxyapatite embedded in graphitic carbon nitride nanocomposites for potential tissue engineering applications

Sr-hydroxyapatite has drawn much attention with promising applications in biomedical engineering especially in drug delivery and tissue repair. A novel protocol for the preparation of Strontium hydroxyapatite (Sr-HAP) and Strontium hydroxyapatite encapsulated by graphitic carbon nitride (Sr-HAP@gCN) with high purity and better homogeneity was adopted for potential use in orthopaedic surgeries. The physiological pathway of Strontium and calcium inside humans follow the same trend leading to the mineral deposition of the bone. In the present study, a novel attempt in synthesizing Sr-HAP and Sr-HAP@gCN by the hydrothermal method is proposed for obtaining an ideal biomaterial with potential biocompatibility and pharmacological activity. Phase identification by X-ray diffraction (XRD), Fourier transform Infra-Red spectroscopic analysis (FTIR), Electron & atomic force microscopic studies, Thermogravimetric and Raman spectroscopic analysis was performed on the prepared Sr-HAP and Sr-HAP@gCN to characterize the incorporation efficiency of Strontium. Resazurin microtiter assay and MTT assay were used to evaluate antimicrobial susceptibility and biocompatibility. The typical crystal phase of Sr-HAP and a phase change in Sr-HAP@gCN have been demonstrated with special reference to the interfacial connection between gCN and Sr-HAP through FT-IR studies. Raman spectroscopy revealed the archetypal signature of symmetric and asymmetric PO vibrations pertaining to linearity change with the addition of Strontium. The biological effect of Sr-HAP and Sr-HAP@gCN was quite significant in inducing mineralization when kept immersed in simulated body fluid (SBF) for 21 days. Promising results pertaining to antimicrobial susceptibility and biocompatibility have been proved as an encouraging choice for drug delivery applications and bone filling applications.

Trichoderma harzianum TIND02 upregulates the expression of pathogenesis-related genes and enzymes and enhances gray blight resistance in tea

The gray blight incited by Pestalotiopsis and allied genera is a prevalent disease affecting tea cultivation, and managing it with Trichoderma spp. is an alternative to synthetic fungicides. Plants modify their arsenal system against pathogens when they are exposed to Trichoderma spp., which produces proteins and enzymes associated with pathogenesis. Understanding the expression pattern of defense-related markers will help in developing gray blight resistance tea cultivars. Thus, this study intended to induce resistance against gray blight in tea by Trichoderma harzianum TIND02. For this, a total of eight Trichoderma isolates originated from organic tea rhizospheres were characterized and evaluated for their efficacy. Dual culture test revealed isolate TIND02 as the most potential candidate with 74.6% inhibitory activity against gray blight pathogen Pseudopestalotiopsis theae. Molecular characterization based on ITS and tef-1 alpha genes confirmed isolate TIND02 as T. harzianum. Scanning electron microscopic study showed the mycoparasitic nature of T. harzianum TIND02 (TH-TIND02) to Ps. theae. The ethyl acetate extract of TH-TIND02 at 100 and 200 μg mL−1 showed potential inhibitory activity (>69.9%) against Ps. theae which confirmed the presence of higher volatile metabolites. Gas chromatography–Mass spectrometry study revealed that ethyl acetate extract of TH-TIND02 was composed of 21 major and minor volatile organic compounds with acetamide, 2, 2, 2-trifluoro-N, N-bis trimethyIsilyl–C (94.74%) as a major component. The isolate also produced chitinase, cellulase, β-1, 3 glucanase, and protease hydrolytic enzymes. Nursery experiments revealed that 2% and 5% doses (2 × 106 CFU mL−1) of TH-TIND02 significantly reduced respective 65.0% and 70.0% disease severity over control with improved plant growth. Besides, expressions of defense-related enzymes (chitinase, pHenolics, peroxidase, phenylalanine ammonia lyase, β-1, 3-glucanase, and polyphenol oxidase) and pathogenesis-related genes (chitinase and β-1, 3-glucanase) due to TH-TIND02 were determined. The secretion of defense-related enzymes was highly upregulated in plants applied with TH-TIND02 followed by Ps. theae inoculation compared to controls. The RT-qPCR analysis showed that the expression of both genes in co-inoculated plants was two-fold higher than in control after 21-day post incubation. These results suggest that TH-TIND02 application reduced gray blight severity by elevated enzyme activity and overexpressed pathogenesis-related genes in tea plants which offer for its eco-friendly and sustainable use as a bio-fungicide in tea gardens.

Synthesis, Studies of HDTDHP-μ Crystals from Arundina graminifolia Specimen for Electronic, Photonic, Optical and Electrical Use Correlated with Macro-Crystals for Sensor and Display Uses

A 7-hydroxy-2,4-dimethoxy-9,10-dihydrophenanthrene-HDTDHP macro-crystalline sample is synthesized in a time duration of 23 days with a monoclinic form of crystal with space group as P21/n and the lattice constants are slightly higher than earlier reported macro-HDTDHP. The macro ones are well-milled to get the micro ones and a scanning electron microscopy study of the HDTDHP-μ crystal was analyzed to identify the micro level average scaling in microns. The increased value of the dielectric constant at lower range of frequencies is by the effect of all kinds of polarizations; also, the dielectric loss is measured as decrease in values with the increase in frequencies at room temperature. The electronic-micro filter use is 4.0196 microns for micro influx as the proper opto-electronic, extended NLO type employability as ascertained from transmittance spectral data. The HDTDHP micro-crystalline material is mainly used in micro-photonics, in filtering as micro-influx delineation, in NLO usefulness as opto-electronic agent by the transmittance data and in frequency enhancing and projective utilization in displays. Also, display profile of (111) mode of HDTDHP by without and with recursively assigned colors for RGBR polygonal matrix by software and sensor work sensitiveness of both scaling are measured and reported.

Growth, Characterizations of Aspartame-ASP Crystals for Mechano, Spectral, Photonic, Opto-Electronic and Sensor Applications

The organic crystal has prevalent outcome and Aspartame-ASP crystal which is in anhydrate form is of 160–200 times sweeter than the sucrose and the single crystalline X-ray diffraction (XRD) data for ASP are a, b, c in Å as 19.4077, 4.9604, 15.6547, and alpha and gamma as 90°, beta as 94.877° and system is monoclinic, the space group is P21. The XRD reveals the monoclinic arrangement of the ASP crystal, the UV effect with Tauc’s plot for lower frequency cut off at 295 nm and band gap as 4.203 eV, morphology by scanning electron microscopy study in μm scaling, Vicker’s proviso by hardness profile, basic functional groups by Fourier transform infrared and basic examinations, excitation—emission by PhotoLuminescence-PL peak at 513 nm, electronic sort of ASP filters in 4.3275 microns, electric depiction by dielectric study and mechano use by hardness profile of ASP are studied and reported. Hardness coefficient by Vicker’s intended for ASP with n as 2.91. The NLO-SHG is of 1.76 times KDP with phase matched effect of ASP is reported. Also, the room-temperature sensor study of ASP is measured and compliance by red light-emitting diode source.

α-Ta films on c-plane sapphire with enhanced microstructure

Superconducting films of α-Ta are promising candidates for the fabrication of advanced superconducting qubits. However, α-Ta films suffer from many growth-induced structural inadequacies that negatively affect their performance. We have therefore explored a new synthesis method for α-Ta films, which allows for the growth of these films with an unprecedented quality. Using this method, high quality α-Ta films are deposited at a comparably high substrate temperature of 1150 °C. They are single-phase α-Ta and have a single out-of-plane (110) orientation. They consist of grains ≥2 μm that have one of three possible in-plane orientations. As shown by scanning transmission electron microscopy and electron energy loss studies, the substrate–film interfaces are sharp with no observable intermixing. The obtained insights into the epitaxial growth of body-centered-cubic films on quasi-hexagonal substrates lay the basis for harnessing the high structural coherence of such films in various applications.

Hydrothermally grown copper cobalt phosphate hydrate nanostars for supercapacitors: Investigation of their charge transfer kinetics

The transition bimetal phosphates are optimistic materials for supercapacitors. In this study, copper cobalt phosphate hydrate ((Cu0.35Co0.65)3(PO4)2·H2O) (CCPH) was deposited on Nickel foam using a hydrothermal method at different reaction temperatures as 120, 150, and 180 °C. X-ray diffraction analysis results in the monoclinic crystal structure of CCPH. The Raman study confirms the presence of the phosphate group. The scanning electron microscopy (SEM) study reveals that the reaction temperature-dependent morphological evolution takes place from nanostars to three dimensional (3D)-porous spongy balls-like structure. The elevating reaction temperature has changed the morphology from nanostars to 3D-porous spongy balls. The electrochemical analysis of the CCPH12 electrode resulted in a specific capacitance of 3390.73 mF/cm2 (518.02 µAh/cm2) at 10 mA/cm2 current density. The charge storage dynamics of the CCPH electrodes were analyzed using power law. The CCPH12 electrode delivered the energy density and power density as 0.142 mWh/cm2 and 2.75 mW/cm2, respectively.

Enhanced oxygen reduction reaction with rare-earth metal-based Ce-N-C catalyst

An atomically dispersed single atom catalyst based on rare-earth metal, Cerium embedded into the porous N-doped carbon (Ce-N-C), has been synthesized by using metal-organic framework method. The Ce-N-C catalyst have been physiochemically and electrochemically characterized in detail. Transmission electron microscope studies revealed atomically dispersed Ce atoms on the N-doped carbon support. The electrochemical oxygen reduction reaction (ORR) kinetics of Ce-N-C-3 catalyst revealed an admirable activity with a half-wave potential of 0.89 V, nearly equal to state-of-the-art Pt/C catalyst. The K-L plots and RRDE measurements revealed a nearly direct 4 electron reduction of O2 to H2O by Ce-N-C-3 catalyst. In addition, the chronoamperometry studies with a simulated H2O2 environments clearly revealed the significance of Ce3+/Ce4+ redox couple in deactivating hydrogen peroxide and/or hydroperoxide radicals. The commendable ORR activity, stability and peroxide resistance of Ce-N-C-3 catalysts is credited to the high surface area, atomically dispersed Ce atoms, formation of Ce-N4-C active sites in the catalysts, evidenced from the XPS analysis, in addition to the significance of Ce3+/Ce4+ redox couple in the catalyst. Most importantly, chronoamperometric studies revealed clear evidence of Ce3+/Ce4+ couple significance, helping in effectively mitigating the peroxide related detrimental effects to the ORR catalyst.

Study of quality indicators of gravure imprints obtained with fluorescent ink

The peculiarities of the decoration of gravure imprints on cardboard using fluorescent inks are considered. The influence of the number of fluorescent impurities added to gravure printing ink on the optical indicators of printed image quality, particularly optical density, and gloss, is investigated. Increasing the number of fluorescent impurities added to the ink from 10 to 30% helps to increase the gloss on imprints from 2 to 15 units. Conducted thermogravimetric studies show the resistance of fluorescent imprints to the influence of temperatures during drying in the printing process. The topography of the surface of the substrates and its influence on the quality of imprints is studied. Conducted electron microscopic studies of imprints obtained with inks with different amounts of fluorescent impurities show their uniform distribution on the surface of the substrate. Studies of the fluorescence spectra of the ink and the imprints formed by it confirm the phenomenon of an increase in the intensity of the glow of printed images. The studies confirm the well-known influence of substrate roughness on the smoothness of gravure imprints. It is established that the absence of significant macro irregularities on the surface of Koppargloss FBB cardboard is due to the presence of two coating layers. Analysis of the surface profiles of FBB cardboard shows that its roughness parameter (Ra = 0.424 μm) is three times smaller compared to Incada Silk С GC1 cardboard (the roughness parameter Ra = 1.28 μm), with a single-layer coating. Such a pattern is also preserved on the imprints, which is reflected in their quality accordingly. Studies show that for imprints on GC1 cardboard, the average ΔE value is 2.23, for imprints on FBB cardboard, the average ΔE value is 3.71, which is due to the presence of double coating. The factors that can influence the process of fluorescence of printed images are outlined. The technological characteristics of inks for gravure printing on packaging are described.

RETRACTION: Preventive Effect of Naringin on Cardiac Mitochondrial Enzymes During Isoproterenol-induced Myocardial Infarction in Rats: A Transmission Electron Microscopic Study.

M. Rajadurai and P. Stanely Mainzen Prince, "Preventive Effect of Naringin on Cardiac Mitochondrial Enzymes During Isoproterenol-induced Myocardial Infarction in Rats: A Transmission Electron Microscopic Study," by Journal of Biochemical and Molecular Toxicology 21, no. 6 (2007): 354-361, https://doi.org/10.1002/jbt.20203. The above article, published online on 9 November 2007 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editor-in-Chief, Hari K. Bhat; and Wiley Periodicals, LLC. The retraction has been agreed due to duplication of panels presented in figure 3b and 3 f. The authors did not provide an explanation or their raw data. The editors consider the results and conclusion reported in this article unreliable.

Histochemical and ultrastructural localization of triterpene saponins in Medicago truncatula.

In the Medicago genus, saponins are complex mixtures of triterpene pentacyclic glycosides extensively studied for their different and economically relevant biological and pharmaceutical properties. This research is aimed at determining for the first time the tissue and cellular localization of triterpene saponins in vegetative organs of Medicago truncatula, a model plant species for legumes, by histochemistry and transmission electron microscopy. The results showed that saponins are present mainly in the palisade mesophyll layer of leaves, whereas in stems they are mostly located in the primary phloem and the subepidermal cells of cortical parenchyma. In root tissue, saponins occur in the secondary phloem region. Transmission electron microscopy revealed prominent saponin accumulation within the leaf and stem chloroplasts, while in the roots the saponins are found in the vesicular structures. Our results demonstrate the feasibility of using histochemistry and transmission electron microscopy to localize M. truncatula saponins at tissue and cellular levels and provide important information for further studies on biosynthesis and regulation of valuable bioactive saponins on agronomic relevant Medicago spp., such as alfalfa (Medicago sativa L.). RESEARCH HIGHLIGHTS: The Medicago genus represents a valuable rich source of saponins, one of the most interesting groups of secondary plant metabolites, which possess relevant biological and pharmacological properties. Plant tissue and cellular localization of saponins is of great importance to better understand their biological functions, biosynthetic pathway, and regulatory mechanisms. We elucidate the localization of saponins in Medicago truncatula with histochemical and transmission electron microscopy studies.

Epilepsy Research in the Institute of Physiology of the Czech Academy of Sciences in Prague.

Starting from simple clinical statistics, the spectrum of methods used in epilepsy research in the Institute of Physiology of the Czechoslovak (now Czech) Academy of Sciences progressively increased. Professor Servít used electrophysiological methods for study of brain activity in lower vertebrates, neuropathology was focused on electronmicroscopic study of cortical epileptic focus and ion-sensitive microelectrodes were used for studies of cortical direct current potentials. Developmental studies used electrophysiological methods (activity and projection of cortical epileptic foci, EEG under the influence of convulsant drugs, hippocampal, thalamic and cortical electrical stimulation for induction of epileptic afterdischarges and postictal period). Extensive pharmacological studies used seizures elicited by convulsant drugs (at first pentylenetetrazol but also other GABA antagonists as well as agonists of glutamate receptors). Motor performance and behavior were also studied during brain maturation. The last but not least molecular biology was included into the spectrum of methods. Many original data were published making a background of position of our laboratory in the first line of laboratories interested in brain development.

High-sensitive and fast-responsive In2O3 thin film sensors for dual detection of NO2 and H2S gases at room temperature

In this work, the room-temperature dual gas sensing characteristics of indium oxide (In2O3) thin films towards NO2 and H2S have been studied. In2O3 thin films were synthesized by the thermal oxidation of indium metal films of various thicknesses in the range of 50–250 nm deposited by thermal evaporation method. Grazing incidence X-ray diffraction (GI-XRD) revealed the change in preferred orientation of In2O3 thin films corresponding to varying thickness, while field-emission electron microscopy studies showcased evolving surface morphologies from individual grains to granular network with respect to the increase in film thickness. Investigations were made on the ability of In2O3 thin films to detect various low concentrations of nitrogen dioxide (NO2) and hydrogen sulfide (H2S) gases at ambient temperature. In2O3 thin films synthesized using 100 nm thick In films exhibited good sensing response of around 58 and 68 % towards NO2 and H2S gases of 5 ppm respectively, at room temperature (27 °C) with the response time of 36 and 18 s. Remarkably, the lower experimental detection limit of these toxic gases could be extended up to 100 ppb. Using X-ray photoelectron spectroscopy, a large presence of surface oxygen is observed on the In2O3 thin film. The sensor has demonstrated remarkable sensing abilities, including strong selectivity, quick sensing response, and good repeatability.

Spirulina platensis as a super prebiotic to enhance the antibacterial effect of Lactobacillus casei

Microalgae are diminutive unicellular magnificent creatures that exist in the microscopic form. Within this classification, two notable subtypes, namely Spirulina platensis and Chlorella vulgaris, have garnered significant attention. S. platensis is mostly known for its therapeutic benefits due to proteins, vitamins, essential amino acids, minerals, and essential fatty acids abundance.The subsequent work aimed to investigate the prebiotic effect of S. platensis enhancing Lactobacillus casei microbiome growth rate and antibacterial effect. Different concentrations of S. platensis were prepared (0, 0.5, 5, and 50 mg/mL) then co-cultured with L. casei. Live probiotic enumeration, molecular characterization and scanning electron microscopy studies were performed. Data revealed that 5 mg/mL of S. platensis significantly enhanced the probiotic live count and consequently the antibacterial activity. The antibacterial and antibiofilm effects of L. casei/S. platensis mixture showed complete inhibition to the growth of bacterial cells after 4- and 8-h incubation with Staphylococcus epidermidis 12228 and Escherichia coli 25922, respectively. Moreover, minimal biofilm eradication concentration (MBEC) value of 16 µg/mL was recorded for L. casei/S. platensis mixture

The possible protective effect of ginger extract on toxic changes induced by bisphenol A on the thyroid gland of adult male albino rats: light and electron microscopic study.

Bisphenol A (BPA) is a chemical substance used in the plastic industry and considered as an endocrine disruptor. Ginger is a herbal material used in the food industry and has antioxidant activity. The present study was performed to evaluate the histological changes in the thyroid gland of adult male albino rats after intake of BPA and if there is any protective role for ginger extract (GE). Eighty adult male rats were divided equally into four groups. Group I as a control group, group II included rats that received 250 mg/kg/day GE orally for eight weeks, group III included rats that received 200 mg/kg/day BPA orally for the same period and group IV included rats that received BPA in the same dose for the same duration concomitantly with GE. At the end of the experiment, blood samples were taken for hormonal essay and tissue samples were processed. Light and electron microscopic studies were done. Morphometric and statistical studies were carried out. Group III showed degenerative changes in the thyroid gland, decreased serum levels of T3 and T4 and a strong positive inducible nitric oxide synthase (iNOS) immune response. Group IV showed restoration of thyroid gland architecture and function. In conclusion, GE protected the thyroid structure from the damaging effect of BPA oxidative stress through its anti-oxidant effect, thus preserving thyroid activity.

Aging behavior, microstructure and mechanical properties of Al-Cu-Mg alloy matrix composites reinforced with carbon nanotubes

High-strength Al-Cu-Mg alloys are good matrix candidates for fabricating strong and tough Al matrix composites reinforced with carbon nanotubes (CNTs). In this study, an element mechanical alloying method was used to achieve homogeneous CNT dispersion in hard Al-Cu-Mg matrix. A comprehensive transmission electron microscopy study was applied on peak-aged CNTs/Al-Cu-Mg composites and referential Al-Cu-Mg alloy. It was found that the ex-situ CNTs increased the dislocation density and hindered the recrystallization of the Al-Cu-Mg matrix. Thus, larger local stress and strain were detected in CNTs/Al-Cu-Mg composites. The precipitation in CNTs/Al-Cu-Mg composites was accelerated, which brought extra 12 % improvement to tensile yield strength of the composite. The distribution of precipitates in CNTs/Al-Cu-Mg composites were nonuniform due to the element mechanical alloying process, which was probably beneficial to the high ductility of the CNTs/Al-Cu-Mg composite. With the synergetic strengthening effect of CNTs and fine precipitates, CNTs/Al-Cu-Mg composites exhibited well-balanced strength and ductility.

Effect of sodium dodecyl sulfate on the dielectric and electrical properties of poly (vinylidene fluoride)-zinc ferrite composites

Polymer composites comprising Poly (vinylidene fluoride) (PVDF) as a matrix, Zinc Ferrite (ZnFe2O4: ZFO) as ceramic filler and Sodium Dodecyl Sulfate (SDS) as a surface modifying agent have been synthesized through a simple solvent casting route for application in energy storage devices. The Scanning Electron Microscopic (SEM) study confirmed that the surface modification through Sodium Dodecyl Sulphate improved the dispersion of ZFO particles in the PVDF matrix. The FTIR Spectrophotometer study revealed the existence of expected functional groups in the modified composites The advantage of treatment of SDS on the composite obtained from blending of PVDF with Zinc Ferrite was investigated. The Impedance Analyzer study indicated that the composite with 1.5 wt.% Zinc Ferrite nanoparticles encapsulated by SDS exhibited the highest dielectric constant and reduced loss tangent. In addition, the experimental values of the dielectric constant were compared with some theoretical models. Further, the PE loop study showed higher remanent polarisation in the 1.5 wt.% SDS treated composite indicating that treatment of SDS on Zinc Ferrite (ZFO) can be adopted to fabricate composites for high energy storage applications.

Ultrasonic assisted synthesis of nanoporous carbon/CeVO4 nanocomposite for supercapacitor and photocatalytic applications

Here, nanoporous carbon (NPC)/CeVO4 nanocomposite synthesized via ultrasonic assisted method for supercapacitor and tartrazine dye degradation application. Transmission electron microscope (TEM) studies confirmed the CeVO4 nanoparticles well embedded on the NPC surface in the NPC/CeVO4 nanocomposite. Spherical shaped CeVO4 nanoparticles are well incorporated on the surface of NPC therefore NPC/CeVO4 nanocomposite which possess a porous-like structure would improve the supercapacitor applications and dye degradation performance. As expected, the specific capacitance (Cs) values (555 F g−1) of NPC/CeVO4 nanocomposite showed enhanced performance as compared to CeVO4 nanoparticles (234 F g−1) at a current density of 1 A g−1 and the capacitance retention of the designed electrode as 95 % after 5000 cycles. The photodegradation of tartrazine dye using pure CeVO4 nanoparticles and NPC/CeVO4 nanocomposite was explored under visible light irradiation. The photocatalytic degradation experiment demonstrated that the NPC/CeVO4 exhibits the maximum degradation efficiency (98.76 %) of the tartrazine with was reached within 120 min. Moreover, the rate constant of NPC/CeVO4 for tartrazine dyes decomposition was 0.0192 min−1 representing that it is two-fold higher than pure CeVO4 (0.0073 min−1). The superior electrochemical and photocatalytic properties of NPC/CeVO4 nanocomposite have been observed due to the well-designed structure and high surface area. Consequently, as-prepared NPC/CeVO4 material could be a promising material for electrochemical supercapacitor and dye degradation of the tartrazine organic pollutant.

Co-axially electrospun Li-rich layered Oxide@Spinel core-shell heterostructure nanofibers for enhanced stability and electrochemical performance

Lithium-rich layered oxides (LLO) possessing high specific capacity has the limitation of voltage fade, poor high C-rate performance and low conductivity. Spinel coating on LLO surface is known to mitigate the voltage fade, however, enabling high C-rate performance remains challenging. In this study, LLO nanofiber core with composition 0.6Li2MnO3·0.4LiMn0.25Ni0.38Co0.37O2 is prepared by electrospinning process and the same is coated with spinel LiMn1.5Ni0.5O4 shell to obtain LLO/spinel (LLO/S) core-shell heterostructure. The spinel shell coating is accomplished (i) by a novel co-axial (CA) electrospinning process and (ii) by wet chemical (WC) approach. The CA electrospinning process provides a uniform core-shell structure compared to the WC process. The electron microscopy studies reveal the fibrous microstructure in LLO/S heterostructures with energy dispersive spectroscopy compositional mapping showing the spinel composition on the surface. Higher concentration (>10 wt.%) of spinel coating are shown to break the fibers into particulates. X-ray diffraction and high-resolution transmission electron microscopy analysis confirm the spinel structure formation along with layered structure. While the capacity is slightly compromised compared to the pristine LLO nanofiber, the LLO/S heterostructure with 10 wt.% spinel coating exhibits a high reversible capacity of 268 mAhg-1 with minimal capacity loss during the 1st cycle (with coulombic efficiency 83.5%) and an excellent high C-rate capability (88 mAhg-1 at 10C-rate and 55 mAhg-1 at 20C-rate). The electrochemical studies also demonstrate the importance of optimal spinel content in the coating and the method of spinel coating on the layered material surface. The encapsulation of LLO with spinel layer which has 3D-diffusion pathways for Li-ion transport facilitates high ionic and electronic conductivity and hence leads to enhanced electrochemical performance of LLO/S heterostructured cathodes.