Display omitted
•A novel Ru metal–organic doped PMMA films were fabricated by spin-coating method.•Third-order nonlinear optical susceptibility is of the order of 10−11esu.•All-optical switching ...action based on ESA is discussed.•Modulation of the probe intensity was determined.
Third-order nonlinear optical properties of a novel ruthenium complex (2-thioxo-1,3-dithiole-4,5-dithiolato) triphenylarsenic Ru(III), have been investigated by employing Z-scan and DFWM techniques. The compound shows self-defocusing effect. Its nonlinear refractive index, third-order nonlinear optical susceptibility and the second-order hyperpolarizability are seen to be of the order of 10−9, 10−10 and 10−30esu respectively. The nonlinear absorption coefficient is of the order of 10−9m/W. This material exhibits good optical power limiting capability which is seen to occur due to reverse saturable absorption. Experiments on all-optical switching action indicate that the sample can function as an optical inverter or a NOT gate.
A star‐shaped molecule with a central electron‐deficient triazine ring connected to three electron‐rich N‐annulated perylene tetraesters was synthesized. Its application as an emissive layer in the ...fabrication of a sole and host–guest solution processable OLED, exhibiting bright green emission with good electroluminescence efficiency is demonstrated.
A star‐shaped donor–acceptor molecule containing a central triazine and three perylene tetraester moieties exhibits bright green electroluminescence. This study also provides insights into the molecular design of highly emissive materials as well as the ability to control the singlet and triplet energy differences and may pave the way towards new materials with thermally activated delayed fluorescence (TADF).
Abstract
This paper proposes a tunable filter composed of a semiconductor-insulator-semiconductor (SIS) waveguide with a ring resonator at terahertz(THz) frequency. The two-dimensional study of the ...proposed structure has been done using the finite element method. It is observed that the device can be used for filtering THz frequency within the range of 0.4 THz to 0.9 THz by varying the structural parameters. The simulated structure is a promising candidate for an integrated optical circuit and terahertz devices as a filter. The results of the simulations are discussed in detail.
Alcohol-induced oxidative stress is a key player in the development of liver diseases, and herbal alternatives are important means of ameliorating the hepatotoxic effects. The study aimed to evaluate ...the hepatoprotective potentiality of
Artabotrys odoratissimus
, an important medicinal shrub from the family
Annonaceae.
The phenolic compounds from bark ethanol extract (BEE) were detected using RP-HPLC. The in vitro hepatoprotective activity against ethanol-induced damage was studied in HepG2 cells with cell viability assays, mitochondrial membrane potential (MMP) assay, reactive oxygen species (ROS) assay, double staining assay and western blotting. The in vivo mice model was used to evaluate the alcohol-induced stress with liver function enzymes, lipid profile and histopathology. All the thirteen phenolic compounds detected with HPLC were docked onto protein targets such as aspartate amino transferase (AST), alkaline phosphatase (ALP) and inducible nitric oxide synthase (NO). The RP-HPLC detected the presence of various phenolics including rutin, chlorogenic acid and catechin, amongst others. Co-administration of BEE with ethanol alleviated cell death, ROS and MMP in HepG2 cells compared to the negative control. The extract also modulated the MAP kinase/caspase-3 pathway, thereby showing protective effects in HepG2 cells. Also, pre-treatment for 14 days with the extract in the mice model before a single toxic dose (5 g/kg body weight) reduced the liver injury by bringing the levels of liver function enzymes, lipid profile and bilirubin to near normal. In silico analysis revealed that rutin showed the best binding affinity with all the target proteins in the study. These results provide evidence that BEE possesses significant hepatoprotective effects against ethanol-induced oxidative stress in hepatic cells and in vivo models, which is further validated with in silico analysis.
A high sensitivity refractive index semiconductor-insulator-semiconductor (SIS) waveguide with a ring resonator sensor at THz frequency is proposed. The topological study of the proposed filter is ...numerically simulated using the finite element method. A maximum sensitivity of 0.509 THz/ Refractive index unit (RIU) is obtained by filling the air-filled ring resonator cavity with different refractive index materials. Besides that, the transmission characteristics are studied by varying the structural dimensions and observed that the system can be treated as a frequency selective device. The device gets modified by incorporating another concentric ring inside the single ring. From the transmission characteristics, the multiple modes of the concentric dual ring are studied, and concluded that the even TM 1 mode shows a better response towards frequency tuning.
Terahertz waveguides and resonators have brought numerous applications from biomedical to modern communications. In this paper, we have demonstrated numerically a straight ...semiconductor-insulator-semiconductor(SIS) waveguide attached to a split ring resonator, which acts as a terahertz frequency filter and can be used for refractive index sensing. The device’s transmission properties have been studied using the finite element method. To fix the third dimension of the device, that is the depth of the waveguide the effective mode index and power density calculations are done for the propagating mode. The frequency tuning of the filter is achieved by changing the geometric parameters of the waveguide and resonator system such as ring radii and split width. Both the symmetric and antisymmetric modes of the split ring show almost the same rate of change of resonance frequency with the change in geometric parameters. To demonstrate the importance of the split position, the transmittance is studied by placing the split at different positions on the ring. We obtained the same transmittance for the split at left and right positions, whereas the split at the top and bottom shows different transmittance similar to the transmittance of a ring resonator. The symmetric and antisymmetric modes of the split ring are calculated for refractive index sensing and the highest sensitivity of 0.741 THz/ refractive index unit (RIU) for the symmetric mode as expected.
Hydrazides are known to exhibit keto‐enol tautomerism upon photoexcitation. Theoretical aspects uncovering excited state intramolecular proton transfer (ESIPT) of N‐acylsubstituted hydrazides with ...bithiophene core have been investigated. Geometrical aspects of the system are expected to undergo double proton translocation at its excited state. However, potential energy surface study for all the molecules reveals an impossible concurrent double proton translocation and to a greater extent dubious step‐wise double proton translocation in the system. Potential energy scans reveal molecules possessing a lower forward barrier at its excited state in comparison with their ground state suggestive of possible excited state single proton transfer. Geometrical attributes and spectral analysis suggest the strengthening of intramolecular hydrogen bond (N―H▪▪▪O) at its excited state, favoring single proton translocation. Theoretical estimation of electronic energy transition for all the conformers yields good correlation with the experimental figures with an energy overestimation <0.17 eV.
Hydrazides undergo keto‐enol tautomerism and theoretical aspects uncovering the excited state intramolecular proton transfer (ESIPT) phenomena is explored in the present work. Geometrical aspects of the system is expected to support simultaneous double proton transfer upon photoexcitation. Potential energy surface study on the system reveals an impossible simultaneous double proton transfer and a doubtful stepwise double proton transfer. Potential energy scans on molecules reveal system to support single proton transfer at its excited state.
Metal hydroxides and alkoxides are popular base catalysts for production of fatty acid methyl esters (FAME). Hydroxides dissolved in alcohols produce water. Some of that water reacts with ...triacylglycerols (TAGs) to produce free fatty acids instead of desired FAME, thus decreasing the yield of the transesterification reaction. Metal alkoxides are expensive, their production is hazardous and energy intensive, therefore, less expensive safer and more efficient catalysts for transesterification are desirable. Glycerol derived non‐toxic alkoxide base catalysts were synthesized by heating KOH solution (50 wt%) and glycerol at three different mole ratios (KOH: glycerol, denoted KGly, at 1:1, 2:1, and 3:1) under four different vacuum pressures. Transesterification reactions were conducted. The reaction rate and yield of FAME synthesis from TAG achieved by catalyst prepared at 3:1 mole ratio of KOH: glycerol achieved superior or similar FAME yield to conventional potassium methoxide catalyst under same reaction conditions. At 120 s after adding catalyst, the reactions achieved satisfactory yield (74.3–78.9%) which was similar to that of KOCH₃ catalyst (77.9%). The reactivity of catalyst at initial stage of the reaction was in the following order: KGly (1:1) < KGly (2:1) < KOCH₃ < KGly (3:1). Glycerol derived non‐toxic alkoxide base catalysts were synthesized by heating KOH solution (50 wt%) and glycerol at three different mole ratios (KOH: glycerol, 1:1, 2:1, and 3:1) under four different vacuum pressures. The catalysts were used for transesterification reaction and the catalyst prepared at 3:1 mole ratio achieved superior or similar FAME yield to conventional potassium methoxide catalyst.
Inflammation is a complex biological response involving immune cells to an infection creating injury to the normal tissues. The anti-inflammatory efficacy of embelin, a benzoquinone from the plant
...Embelia ribes
, was screened for antioxidant and anti-inflammatory activity in carrageenan and Freund’s adjuvant-induced inflammation models. Embelin exhibited significant dose-dependent antioxidant potential. In carrageenan-induced inflammation, embelin (20 mg/kg) showed an inhibition of oedema by 71.01 ± 0.12% and 81.91 ± 0.67% in Freund’s adjuvant-treated chronic inflammation model and resulted in a noticeable increase in adrenal size and restoration of the weight of spleen. Embelin also demonstrated cytoprotective effects on HEK-293 cells under induced oxidative stress. In silico analysis, embelin demonstrated binding energy of − 7.7 kcal/Mol and − 7.0 kcal/Mol with COX1 and COX2 with two hydrogen bonds. These results further prove that embelin could be a promising anti-inflammatory agent and supports the traditional use of
Embelia ribes
for rheumatism.
A study has been performed by investigating the variation of absorbance and photoluminescence intensity of the perovskite as a function of precursor mixing ratios at room temperature. In this study ...we used CH3NH3SnCl3 perovskite wherein CH3NH3Cl and SnCl2 solutions are the precursors. These two precursors are mixed with ratios of 3:1, 1:1 and 1:3. XRD, UV–Vis absorption and photoluminescence studies were carried out in both solution and film form.
