Manganese enhances cadmium tolerance in barley through mediating chloroplast integrity, antioxidant system, and HvNRAMP expression.

Cadmium (Cd) is a toxic heavy metal that poses risks to crop production and food safety worldwide. This study evaluated whether manganese (Mn) addition could mitigate Cd toxicity and reduce Cd accumulation in barley seedlings. Hydroponically grown seedlings of Cd-tolerant (WSBZ) and Cd-sensitive (Dong17) barley cultivars were treated with 0.1 µM and 1 µM Cd as well as 0.2 mM Mn alone and in a combination with 0.1 or 1.0 µM Cd for 21 days. Cd exposure caused the dramatic alteration of growth and physiological parameters by disrupting chloroplast, and increased Cd accumulation in both genotypes. However, Mn addition markedly alleviated the negative impacts of all examined parameters caused by Cd stress. Cd addition enhanced expression of anti-oxidative enzyme related genes, including HvSOD, HvCAT, HvAPX, HvPOD in the two barley genotypes exposed to Cd stress. The expression analysis showed nearly all HvNRAMPs genes are dramatically up regulated by both Mn and Cd, with WSBZ having higher expression than Dong 17. Notably, HvNRAMP1 showed the highest expression due to Mn addition, highlighting its crucial role in Mn uptake and transportation in barley. Moreover, Cd stress and Mn addition increased and suppressed the expression of HvYSL5, HvHMA2 and HvHMA3, respectively. Conversely, the expression of HvYSL2, HvIRT1 and HvMTP8 was upregulated by both Mn and Cd treatments, with a further increase observed in the combined Cd and Mn treatments. It may be concluded that sufficient Mn supply is quite important for reducing Cd uptake and accumulation in plants.

NRAMPs and manganese: Magic keys to reduce cadmium toxicity and accumulation in plants.

Cadmium (Cd), a toxic heavy metal, poses significant threats to both crop production and human health worldwide. Manganese (Mn), an essential micronutrient, plays a crucial role in plant growth and development. NRAMPs (Natural Resistance-Associated Macrophage Proteins) function as common transporters for both Cd and Mn. Deep understanding of the regulatory mechanisms governing NRAMP-mediated Cd and Mn transport is imperative for developing the crop varieties with high tolerance and low accumulation of Cd. This review reported the advance in studies on the fundamental properties and classification of NRAMPs in plants, and structural characteristics, expression patterns, and diverse functions of NRAMP genes across different plant species. We highlighted the pivotal role of NRAMPs in Cd/Mn uptake and transport in plants as a common transporter. Finally, we also comprehensively discussed over the strategies for reducing Cd uptake and accumulation in plants through using antagonism of Mn over Cd and altering the expression of NRAMP genes.

Recent developments in chitosan based microgels and their hybrids.

Chitosan based microgels have gained great attention because of their chemical stability, biocompatibility, easy functionalization and potential uses in numerous fields. Production, properties, characterization and applications of chitosan based microgels have been systematically reviewed in this article. Some of these systems exhibit responsive behavior towards external stimuli like pH, light, temperature, glucose, etc. in terms of swelling/deswelling in an aqueous medium depending upon the functionalities present in the network which makes them a potential candidate for various applications in the fields of biomedicine, agriculture, catalysis, sensing and nanotechnology. Current research development and critical overview in this field accompanying by future possibilities is presented. The discussion is concluded with recommended possible future works for further progress in this field.

Interactive mode of biochar-based silicon and iron nanoparticles mitigated Cd-toxicity in maize.

Cadmium contamination poses severe environmental and health threats, necessitating effective mitigation strategies. Rice husk biochar (BC) and nanoparticle (NP) treatments are emerging strategies with limited research on their synergistic benefits. This study assesses BC, silicon NPs (nSi), and iron NPs (nFe) modifications (B-nSi, B-nFe, and B-nSi-nFe) to reduce Cd-bioavailability in soil and its toxicity in maize, not reported before. Characterization of amendments validated, nSi and nFe attachment to BC, forming new mineral crystals to adsorb Cd. We found that B-nSi-nFe induced Cd-immobilization in soil by the formation of Cd-ligand complexes with the effective retention of NPs within microporous structure of BC. B-nSi-nFe increased soil pH by 0.76 units while reducing bioavailable Cd by 49 %, than Ck-Cd. Resultantly, B-nSi-nFe reduced Cd concentrations in roots and shoots by 51 % and 75 %, respectively. Moreover, the application of B-nSi-nFe significantly enhanced plant biomass, antioxidant activities, and upregulated the expression of antioxidant genes [ZmAPX (3.28 FC), ZmCAT (3.20 FC), ZmPOD (2.58 FC), ZmSOD (3.08 FC), ZmGSH (3.17 FC), and ZmMDHAR (3.80 FC)] while downregulating Cd transporter genes [ZmNramp5 (3.65 FC), ZmHMA2 (2.92 FC), and ZmHMA3 (3.40 FC)] compared to Ck-Cd. Additionally, confocal microscopy confirmed the efficacy of B-nSi-nFe in maintaining cell integrity due to reduced oxidative stress. SEM and TEM observations revealed alleviation of Cd toxicity to stomata, guard cells, and ultracellular structures with B-nSi-nFe treatment. Overall, this study demonstrated the potential of B-nSi-nFe for reducing Cd mobility in soil-plant system, mitigating Cd-toxicity in plants and improving enzymatic activities in soil.

Exploration of high-performance triptycene-based thermally activated delayed fluorescence materials via structural alteration of donor fragment.

The utilization of thermally activated delayed fluorescence (TADF) materials in highly proficient organic light-emitting diodes (OLEDs) has attracted much attention. Based on TADF material TPA-QNX(CN)2, a series of three-dimensional donor-acceptor (D-A) triptycenes have been designed via structural modification of D-fragment. The influences of different D-fragments with various electron-donating strengths on the singlet-triplet energy gap (ΔEST), emission wavelength (λem), and electron/hole reorganization energy (λe/λh) are extensively studied by applying density functional theory (DFT) coupled with time-dependent density functional theory (TD-DFT). The computed results imply that as the electron-donating strength of the D-fragments increases, the ΔEST value decreases and λem is red-shifted for the molecules using the same acceptor units. Analogously, the 1CT‒3CT state splitting (ΔEST (CT)) is also decreased by enlarging the twist angle (ß) between the phenyl ring and alternative D-fragment. Therefore, efficient color tuning within a broad emission range (434-610 nm), as well as small ΔEST (CT) values (0.01-0.05 eV), has been accomplished by structural modification of the D-fragments. The greater electron-donating strength, the smaller ΔEST, and the smaller λh for PPXZ-QNX(CN)2 make it the best candidate among all the designed molecules.

Sb-Doped Cerium Molybdate: An Emerging Material as Dielectric and Photocatalyst for the Removal of Diclofenac Potassium from Aqueous Media.

This work reports the influence of antimony substitution in a cerium molybdate lattice for improved dielectric and photocatalytic properties. For this purpose, a series of Ce2-xSbx(MoO4)3 (x = 0.00, 0.01, 0.03, 0.05, 0.07, and 0.09) were synthesized through a co-precipitation route. The as-synthesized materials were characterized for their optical properties, functional groups, chemical oxidation states, structural phases, surface properties, and dielectric characteristics using UV-Vis spectroscopy (UV-Vis), Fourier transform infrared (FTIR) and Raman spectroscopies, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and impedance spectroscopy, respectively. UV-Vis study showed a prominent red shift of absorption maxima and a continuous decrease in band gap (3.35 eV to 2.79 eV) by increasing the dopant concentration. The presence of Ce-O and Mo-O-Mo bonds, detected via FTIR and Raman spectroscopies, are confirmed, indicating the successful synthesis of the desired material. The monoclinic phase was dominant in all materials, and the crystallite size was decreased from 40.29 nm to 29.09 nm by increasing the Sb content. A significant increase in the dielectric constant (ε' = 2.856 × 108, 20 Hz) and a decrease in the loss tan (tanδ = 1.647, 20 Hz) were exhibited as functions of the increasing Sb concentration. Furthermore, the photocatalytic efficiency of pristine cerium molybdate was also increased by 1.24 times against diclofenac potassium by incorporating Sb (x = 0.09) in the cerium molybdate. The photocatalytic efficiency of 85.8% was achieved within 180 min of UV light exposure at optimized conditions. The photocatalytic reaction followed pseudo-first-order kinetics with an apparent rate constant of 0.0105 min-1, and the photocatalyst was recyclable with good photocatalytic activity even after five successive runs. Overall, the as-synthesized Sb-doped cerium molybdate material has proven to be a promising candidate for charge storage devices and a sustainable photocatalyst for wastewater treatment.

Exploration of violet-to-blue thermally activated delayed fluorescence emitters based on "CH/N" and "H/CN" substitutions at diphenylsulphone acceptor. A DFT study.

The violet-to-blue thermally activated delayed fluorescence (TADF) emitters were created employing several substituents based on 5,5-dimethyl-5,10-dihydropyrido [2,3-b][1,8] naphthyridine-diphenylsulphone (DMDHPN-DPS) called 1a via "CH/N" and "H/CN" substitutions at the diphenylsulphone acceptor (DPS) moiety. The parent compound 1a was selected from our former work after extensive research employing "CH/N" substitution on Dimethyl-acridine (DMAC) donor moiety. There is a little overlap amid the highest occupied molecular orbitals (HOMOs) and lowest un-occupied molecular orbitals (LUMOs) due to the distribution of HOMOs and LUMOs primarily on the DMDHPN donor and the DPS acceptor moieties, respectively. It resulted in a narrower energy gap (∆E ST) between the lowest singlet (S1) and triplet (T1) excited state. In nearly all derivatives, the steric hindrance results in a larger torsional angle (85°-98°) between the plane of the DMDHPN and the DPS moieties. The predicted ΔE ST values of the compounds with "H/CN" substitution were lower than those of the comparable "CH/N" substituents, demonstrating the superiority of the reversible inter-system crossing (RISC) from the T1 → S1 state. All derivatives have emission wavelengths (λ em) in the range of 357-449 nm. The LUMO → HOMO transition energies in the S1 states are lowered by the presence of -CN groups or -N = atoms at the ortho or meta sites of a DPS acceptor unit, causing the λ em values to red-shift. Furthermore, the λ em showed a greater red-shift as there were more-CN groups or -N = atoms. Three of the derivatives named 1b, 1g, and 1h, emit violet (394 nm, 399 nm, and 398 nm, respectively), while two others, 1f and 1i, emit blue shade (449 nm each) with reasonable emission intensity peak demonstrating that these derivatives are effective violet-to-blue TADF nominees. The lower ΔE ST value for derivative 1i (0.01 eV) with λ em values of 449 nm make this molecule the finest choice for blue TADF emitter amongst all the studied derivatives. We believe our research might lead to the development of more proficient blue TADF-OLEDs in the future.

Exploring the Influence of Engineering the Linker between the Donor and Acceptor Fragments on Thermally Activated Delayed Fluorescence Characteristics.

We have expounded the unique molecular design architecture for efficient thermally activated delayed fluorescence (TADF) materials based on a donor-linker-acceptor-linker-donor (D-L-A-L-D) framework, which can be employed as predecessors of organic light-emitting diode (OLED) devices. Different from traditional donor-acceptor-type (D-A-type) TADF scaffolds, the D-L-A-L-D structural design avoids direct coupling amid the D and A fragments allowing the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) to be spatially separated. It results in a reduced overlap between HOMOs and LUMOs, thus realizing fairly a slight singlet-triplet energy gap (ΔE ST) and higher photoluminescence quantum yield (Φ). We revealed that manipulating a linker between D and A fragments in intramolecular charge transfer compounds is an auspicious approach for realizing small ΔE ST. Herein, we report a group of organic electroluminescent D-L-A-L-D-type molecules with different electron-donating and electron-accepting moieties using density functional theory calculations and time-dependent density functional theory calculations. Two types of linkers, the π-conjugated phenylene (-C6H4-) and aliphatic alkyl chains or σ-spacer (-CH2- and -CH2-CH2-), were exploited between D and A fragments. In principle, the conjugation in D-π-A-π-D-type molecules and hyperconjugation in D-σ-A-σ-D type molecules encourage the spatial separation of the HOMO-LUMO causing a reduction in the ΔE ST. All the designed molecules show a blue-shift in the emission wavelengths (λem) over the directly linked parent molecules except DPA-DPS-C6H4 and BTPA-DPS-C6H4 which show a red-shift. Violet-blue to green-yellow (376-566 nm) λem was observed from all of the investigated molecules. Other important properties that affect the efficiency of emission quantum yields like frontier molecular orbital analysis, natural population analysis, electron excitation analysis, exciton binding energies, ionization potentials, electronic affinities, and reorganization energies of the designed molecules were also inspected. We are confident that our work will effectively give a straightforward and distinctive approach to building incredibly effective TADF-OLEDs and a new perspective on their structural design.

Degradation of cefadroxil drug by newly designed solar light responsive alcoholic template-based lanthanum ferrite nanoparticles.

In this work, lanthanum ferrite nanoparticles were synthesized via a simple co-precipitation method. Two different templates, namely sorbitol and mannitol, were used in this synthesis to tune the optical, structural, morphological, and photocatalytic properties of lanthanum ferrite. The synthesized lanthanum ferrite-sorbitol (LFOCo-So) and lanthanum ferrite-mannitol (LFOCo-Mo) were investigated through Ultraviolet-Visible (UV-Vis), X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR), Raman, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), and photoluminescence (PL) techniques to study the effects of the templates on the tunable properties of lanthanum ferrite nanoparticles. The UV-Vis study revealed a remarkably small bandgap (2.09 eV) of LFOCo-So compared to the LFOCo-Mo having a band gap of 2.46 eV. XRD analysis revealed a single-phased structure of LFOCo-So, whereas LFOCo-Mo showed different phases. The calculated crystallite sizes of LFOCo-So and LFOCo-Mo were 22 nm and 39 nm, respectively. FTIR spectroscopy indicated the characteristics of metal-oxygen vibrations of perovskites in both lanthanum ferrite (LFO) nanoparticles, whereas a slight shifting of Raman scattering modes in LFOCo-Mo in contrast to LFOCo-So showed the octahedral distortion of the perovskite by changing the template. SEM micrographs indicated porous particles of lanthanum ferrite with LFOCo-So being more uniformly distributed, and EDX confirmed the stoichiometric ratios of the lanthanum, iron, and oxygen in the fabricated lanthanum ferrite. The high-intensity green emission in the photoluminescence spectrum of LFOCo-So indicated more prominent oxygen vacancies than LFOCo-Mo. The photocatalytic efficiency of synthesized LFOCo-So and LFOCo-Mo was investigated against cefadroxil drug under solar light irradiation. At optimized photocatalytic conditions, LFOCo-So showed higher degradation efficiency of 87% in only 20 min than LFOCo-Mo having photocatalytic activity of 81%. The excellent recyclability of the LFOCo-So reflected that it could be reused without affecting photocatalytic efficiency. These findings showed that sorbitol is a useful template for the lanthanum ferrite particles imparting outstanding features, enabling it to be used as an efficient photocatalyst for environmental remediation.

Fabrication of silver nanoparticles within chitosan based microgels for catalysis.

Chitosan based monodisperse poly[chitosan-N-isopropylmethacrylamide-acrylic acid] [P(CNA)] microgels were produced via precipitation polymerization. Resulting crosslinked P(CNA) micro particles were used as micro-reactors to prepare silver nanoparticles within the polymeric network by chemical reduction of Ag+ ions with sodium borohydride. Various techniques including transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-vis) spectroscopy were used to analyze P(CNA) microgels and Ag-P(CNA) hybrid microgels. Catalytic potential of Ag-P(CNA) hybrid system towards individual and simultaneous reduction of various nitroarenes like p-nitrophenol (pNP), o-nitrophenol (oNP), p-nitroaniline (pNA) and o-nitroaniline (oNA) into corresponding aminoarenes using sodium borohydride as a reductant in aqueous medium was evaluated. The catalytic activity of Ag-P(CNA) system towards both the individual and simultaneous reduction of nitroarenes was examined at various concentrations of catalyst. The values of pseudo first order rate constant (k1) for reduction of individual nitroarene and multiple nitroarenes were determined for comparison. The Ag-P(CNA) hybrid microgel system was found to be stable, economical and efficient catalyst for rapid individual and simultaneous reduction of nitroarenes.

Integrating by-products from bioenergy technology to improve the morpho-physiological growth and yield of soybean under acidic soil.

Soil acidity may negatively affect plant growth. By-products (bottom ash (BA), biochar (BC), and biogas slurry (BS)) from bioenergy technology may change the physio-chemical properties of acidic soils and affect the plant growth parameters. The current research work was carried out to determine the impact of different bioenergy by-products to enhance soybean growth and production by alleviating the effects of acidic soil. A total of eight treatments of different bioenergy amendments (BA, BC, and BS) and their combined applications were used as follows; T1 (control), T2 (only biogas slurry); T3 (only bottom ash); T4 (only biochar); T5 (biogas slurry + bottom ash); T6 (biogas slurry + biochar); T7 (bottom ash + biochar); T8 (biochar + bottom ash + biogas slurry). Our results depicted that, the synergistic use of amendment mainly, T8 treatment (BC + BA + BS) was found most effective, which significantly prompted the dry biomass and photosynthetic rate by 42.58% and 13.25% over the T6 treatment respectively. Furthermore, the chlorophyll pigments, photochemical activities, and root growth of soybean plants enhanced significantly under T5 and T8 treatments as compared to the control. Finally, amendments significantly increased the yield in T8 treatment by increasing the pod's number, grain number, 100-grain weight and grain yield by 119.6%, 75%, 24.9%, and 83.7% as compared to T1. Conclusively, amendments are very effective in the reclamation of acidic soil and enhance the post-harvest soil pH at T8 treatment by 41.49% in comparison to T1 treatment. The organic amendments might neutralize the soil pH and change the acidic nature of the soil, which would modify the root growth of soybean and increase the photosynthetic and photochemical activities, resulting in increased soybean growth and yield.

New Hope for Genome Editing in Cultivated Grasses: CRISPR Variants and Application.

With the advent of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated protein (Cas) mediated genome editing, crop improvement has progressed significantly in recent years. In this genome editing tool, CRISPR-associated Cas nucleases are restricted to their target of DNA by their preferred protospacer adjacent motifs (PAMs). A number of CRISPR-Cas variants have been developed e.g. CRISPR-Cas9, -Cas12a and -Cas12b, with different PAM requirements. In this mini-review, we briefly explain the components of the CRISPR-based genome editing tool for crop improvement. Moreover, we intend to highlight the information on the latest development and breakthrough in CRISPR technology, with a focus on a comparison of major variants (CRISPR-Cas9, -Cas12a, and -Cas12b) to the newly developed CRISPR-SpRY that have nearly PAM-less genome editing ability. Additionally, we briefly explain the application of CRISPR technology in the improvement of cultivated grasses with regard to biotic and abiotic stress tolerance as well as improving the quality and yield.

Metal Ion Detection by Carbon Dots-A Review.

Development of economical, sensitive, selective and robust sensors for metal ion sensing is always fascinating for a chemist because traditional routs for their detection involve complicated instrumentation and critical sample preparation procedures. A large number of metal ion detectors including carbon dots (CDs) have been reported for sensitive and selective detection of metal ions. This review comprehensively explores the use of CDs as metallic cation sensors. CDs are being fabricated from variety of carbon sources by employing various synthetic channels. CDs are proved to be efficient colorimetric and fluorimetric detectors due to surface oxygen moieties which are responsible to co-ordinate with metal ions. Doping of CDs with hetero atom such as N, S, B etc. may further enhance their activity toward metal detection. Therefore, designing of CDs having selective sensing properties with low detection limits has gained significant interest.HighlightsCDs have gained much attention as chemical sensors due to their dynamic features i.e. less toxicity, stability, solubility in various solvents, absorption in UV/Vis. region, fluorescence and tunable physico-chemical properties.These are coast effective, sensitive and selective colorimetric and fluorimetric metal ion sensors.Detection of metal ions by CDs involves different mechanisms such as complexation, aggregation, electron transfer, inner filter effect etc.LOD data is an evidence of their greater efficiency.

Photocatalytic Degradation of Cefixime Trihydrate by Bismuth Ferrite Nanoparticles.

The present work was carried out to synthesize bismuth ferrite (BFO) nanoparticles by combustion synthesis, and to evaluate the photocatalytic activity of synthesized bismuth ferrite nanoparticles against cefixime trihydrate. BFO nanoparticles were successfully synthesized using bismuth (III) nitrate and iron (III) nitrate by a combustion synthesis method employing different types of fuels such as maltose, succinic acid, cinnamic acid, and lactose. The effects of the different types of fuels on the morphology and size of the bismuth ferrite nanoparticles were investigated. Characterization of the as-obtained bismuth ferrite nanoparticles was carried out by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-Dispersive Spectroscopy (EDS), N2-sorption analysis, Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-vis) spectroscopy. Photoluminescence studies were also carried out for the various bismuth ferrite nanoparticles obtained. Degradation of cefixime trihydrate was investigated under sunlight to evaluate the photocatalytic properties of the bismuth ferrite nanoparticles, and it was found that the bismuth ferrite nanoparticles followed first-order degradation kinetics in solar irradiation in the degradation of antibiotic, cefixime trihydrate.

Dielectric Properties of Graphene/Titania/Polyvinylidene Fluoride (G/TiO2/PVDF) Nanocomposites.

Flexible electronics have gained eminent importance in recent years due to their high mechanical strength and resistance to environmental conditions, along with their effective energy storage and energy generating abilities. In this work, graphene/ceramic/polymer based flexible dielectric nanocomposites have been prepared and their dielectric properties were characterized. The composite was formulated by combining graphene with rutile and anatase titania, and polyvinylidene fluoride in different weight ratios to achieve optimized dielectric properties and flexibility. After preparation, composites were characterized for their morphologies, structures, functional groups, thermal stability and dielectric characterizations by using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis and impedance spectroscopy. Dielectric results showed that prepared flexible composite exhibited dielectric constant of 70.4 with minor leakage current (tanδ) i.e., 0.39 at 100 Hz. These results were further confirmed by calculating alternating current (AC) conductivity and electric modulus which ensured that prepared material is efficient dielectric material which may be employed in electronic industry for development of next generation flexible energy storage devices.

Facile synthesis of ternary graphene nanocomposites with doped metal oxide and conductive polymers as electrode materials for high performance supercapacitors.

Supercapacitors (SCs) due to their high energy density, fast charge storage and energy transfer, long charge discharge curves and low costs are very attractive for designing new generation of energy storage devices. In this work we present a simple and scalable synthetic approach to engineer ternary composite as electrode material based on combination of graphene with doped metal oxides (iron oxide) and conductive polymer (polypyrrole) with aims to achieve supercapacitors with very high gravimetric and areal capacitances. In the first step a binary composite with graphene mixed with doped iron oxide (rGO/MeFe2O4) (Me = Mn, Ni) was synthesized using new single step process with NaOH acting as a coprecipitation and GO reducing agent. This rGO/MnFe2O4 composite electrode showed gravimetric capacitance of 147 Fg-1 and areal capacitance of 232 mFcm-2 at scan rate of 5 mVs-1. In the final step a conductive polypyrrole was included to prepare a ternary composite graphene/metal doped iron oxide/polypyrrole (rGO/MnFe2O4/Ppy) electrode. Ternary composite electrode showed significantly improved gravimetric capacitance and areal capacitance of 232 Fg-1 and 395 mFcm-2 respectively indicating synergistic impact of Ppy additives. The method is promising to fabricate advanced electrode materials for high performing supercapacitors combining graphene, doped iron oxide and conductive polymers.

Advancing Dielectric and Ferroelectric Properties of Piezoelectric Polymers by Combining Graphene and Ferroelectric Ceramic Additives for Energy Storage Applications.

To address the limitations of piezoelectric polymers which have a low dielectric constant andto improve their dielectric and ferroelectric efficiency for energy storage applications, we designed and characterized a new hybrid composite that contains polyvinylidene fluoride as a dielectric polymer matrix combined with graphene platelets as a conductive and barium titanite as ceramic ferroelectric fillers. Different graphene/barium titanate/polyvinylidene fluoride nanocomposite films were synthesized by changing the concentration of graphene and barium titanate to explore the impact of each component and their potential synergetic effect on dielectric and ferroelectric properties of the composite. Results showed that with an increase in the barium titanate fraction, dielectric efficiency ofthe nanocomposite was improved. Among all synthesized nanocomposite films, graphene/barium titanate/polyvinylidene fluoride nanocomposite in the weight ratio of 0.15:0.5:1 exhibited thehighest dielectric constant of 199 at 40 Hz, i.e., 15 fold greater than that of neat polyvinylidene fluoride film at the same frequency, and possessed a low loss tangent of 0.6. However, AC conductivity and ferroelectric properties of graphene/barium titanate/polyvinylidene fluoride nanocomposite films were enhanced with an increase in the graphene weight fraction. Graphene/barium titanate/polyvinylidene fluoride nanocomposite films with a weight ratio of 0.2:0.1:1 possessed a high AC conductivity of 1.2 × 10-4 S/m at 40 Hz. While remanent polarization, coercive field, and loop area of the same sample were 0.9 µC/cm², 9.78 kV/cm, and 24.5 µC/cm²·V, respectively. Our results showed that a combination of graphene and ferroelectric ceramic additives are an excellent approach to significantly advance the performance of dielectric and ferroelectric properties of piezoelectric polymers for broad applications including energy storage.

Synthesis and Characterization of BaTiO3/Polypyrrole Composites with Exceptional Dielectric Behaviour.

Higher concentrations of ceramic fillers induce brittleness in the ceramic/polymer hybrids which restrict their applications to limited fields especially when such hybrids are prepared for their use as dielectrics. We have synthesized and characterized different BaTiO3-polypyrrole (PPy) composites by changing the concentration of BaTiO3 from 1% by weight of PPy taken to 5 wt % to explore its effect on the dielectric parameters of the final product and found that the BaTiO3-polypyrrole composite with weight ratio of 0.05:1 exhibited highest dielectric constant, lowest dielectric loss and thermally most stable. All the composites were prepared using in-situ polymerization of pyrrole in an aqueous dispersion of low content of BaTiO3 in the presence of small amount of Hydrochloric acid. These composites were characterized for their microstructure and crystallinity by X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) while thermal stability by thermo gravimetric (TGA) analysis. An impedance analyser (LCR meter) was utilized to investigate the dielectric parameters. FT-IR data confirmed the presence of the two phases and their interaction, inferred from the shifting of normal PPy peaks. The data obtained from XRD confirmed the presence of crystallites of 2.8 to 5 nm with dominant crystallinity of the filler, TGA analysis (25 to 600 °C) confirmed the higher thermal stability induced on successive addition of the filler into the prepared composites as compared to that of pure PPy in a wide temperature range which is unusual for such a low % age addition of the filler. The SEM analysis together with XRD results reveal that the successive introduction of BaTiO3 particles produced crystallites of 2 to 5 nm size which bonded together and changed the hemispherical shaped larger grains of the matrix to regular shaped smaller grains. The dielectric constant of the composites was enhanced with filler contents from 178 to 522 at 1 MHz for 1 wt % and 5 wt % BaTiO3 respectively. It was concluded that the introduction of BaTiO3 into the polymer matrix with this new procedure has greatly affected the polymerization process, thermal stability, morphology and dielectric properties of the host matrix and has resulted in a novel series of the composites which may have broad applications.

Stabilization studies of sunflower oil with antioxidants extracted from green and black cardamom.

Extracts from green and black cardamom have been used to evaluate their antioxidant potential for sunflower oil samples for a period of 45 days. Synthetic antioxidants BHA/ BHT were also used parallel over a period of 45 days for comparison. Antioxidant potential of natural and synthetic antioxidants were evaluated by measuring free fatty acids (FFA), peroxide value (PV) and iodine value (IV) values by ambient storage of sunflower oil. The results showed that green cardamom extracts were more effective compared to black cardamom extracts. However compared to BHA and BHT (200ppm), these were found to be effective at higher concentrations.