In recent years, the field of nanophotonics has progressively developed. However, constant demand for the development of new light source still exists at the nanometric scale. Light emissions from graphene-based active materials can provide a leading platform for the development of two dimensional (2-D), flexible, thin, and robust light-emitting sources. The exceptional structure of Dirac's electrons in graphene, massless fermions, and the linear dispersion relationship with ultra-wideband plasmon and tunable surface polarities allows numerous applications in optoelectronics and plasmonics. In this article, we present a comprehensive review of recent developments in graphene-based light-emitting devices. Light emissions from graphene-based devices have been evaluated with different aspects, such as thermal emission, electroluminescence, and plasmons assisted emission. Theoretical investigations, along with experimental demonstration in the development of graphene-based light-emitting devices, have also been reviewed and discussed. Moreover, the graphene-based light-emitting devices are also addressed from the perspective of future applications, such as optical modulators, optical interconnects, and optical sensing. Finally, this review provides a comprehensive discussion on current technological issues and challenges related to the potential applications of emerging graphene-based light-emitting devices.
The food production industry is a significant contributor to the generation of millions of tonnes of waste every day. With the increasing public concern about waste production, utilizing the waste generated from popular fruits and vegetables, which are rich in high-added-value compounds, has become a focal point. By efficiently utilizing food waste, such as waste from the fruit and vegetable industries, we can adopt a sustainable consumption and production pattern that aligns with the Sustainable Development Goals (SDGs). This paper provides an overview of the high-added-value compounds derived from fruit and vegetable waste and their sources. The inclusion of bioactive compounds with antioxidant, antimicrobial, and antibrowning properties can enhance the quality of materials due to the high phenolic content present in them. Waste materials such as peels, seeds, kernels, and pomace are also actively employed as adsorbents, natural colorants, indicators, and enzymes in the food industry. Therefore, this article compiles all consumer-applicable uses of fruit and vegetable waste into a single document.
In this study a cationic surfactant, cetyltrimethylammonium bromide (CTAB), was used as a soft template for in situ chemical polymerization of aniline on the surface of microcrystalline cellulose (MCC). The morphology of the wire-like and porous nanostructure of the resulting composite was highly dependent on the MCC and CTAB concentrations. The effect of the MCC and CTAB concentrations on the electrochemical and morphological properties of the polyaniline (PAni) nanocomposite was studied. Cyclic voltammograms of modified PAni/MCC/CTAB electrode displayed a high current response and the effect of scan rate on the current response confirmed a diffusion controlled process on the surface of the electrode that makes it suitable for sensor applications. The overlapping characteristic peaks of pure PAni and MCC caused peak broadening at 3263 cm-1 in the IR spectra of PAni/MCC/CTAB nanocomposite that revealed the interaction between NH of PAni and OH group of MCC via electrostatic interactions. The addition of MCC to PAni through chemical polymerization decreased the thermal stability of composite compared to pure PAni. Lower crystallinity was observed in the XRD diffractogram, with 2 theta values of 22.8, 16.5, and 34.6 for PAni/MCC, confirming the formation of PAni on the MCC surface.
The microwave-assisted three-component reactions of 3,5-bis(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones, acenaphthenequinone and cyclic α-amino acids in an ionic liquid, 1-butyl-3-methylimidazolium bromide, occurred through a domino sequence affording structurally intriguing diazaheptacyclic cage-like compounds in excellent yields.
(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.
Equol is a soy isoflavone metabolite that can be produced by intestinal bacteria. It is lipophilic and resembles natural oestrogens with an affinity to oestrogen receptors. This review is focused on how equol affects breast cancer, as evidenced by in vivo and in vitro studies. Equol is considered chemoprotective in specific endocrine-related pathologies, such as breast cancer, prostate cancer, cardiovascular diseases, and menopausal symptoms. In humans, not everyone can produce equol from gut metabolism. It is postulated that equol producers benefit more than non-equol producers for all the endocrine-related effects. Equol exists in two enantiomers of R-equol and S-equol. Earlier studies, however, did not specify which enantiomer was being used. This review considers equol's type and concentration variations, pathways affected, and its outcome in in vivo and in vitro studies.
The influence of human salivary enzymes on palm wines' odorant concentrations were investigated by the application of aroma extracts dilution analysis (AEDA) and by the calculation of odour activity values (OAVs), respectively. The odorants were quantified by means of stable isotope dilution assays (SIDA), and the degradation profiles of odorants by human saliva were also studied. Results revealed 46 odour-active compounds in the flavour dilution (FD) factor range of 4-256, and all were subsequently identified. Of the 46 odorants, 41 were identified in the Elaeis guineensis wine, 36 in Raphia hookeri wine and 29 in Borassus flabellifer wine. Among the odorants, the highest FD-factors were obtained from acetoin, 2-acetyl-1-pyrroline and 3-isobutyl-2-methoxypyrazine. Among the 13 potent odorants identified, five aroma compounds are reported here as important contributors to palm wine aroma, namely 3-isobutyl-2-methoxy-pyrazine, acetoin, 2-acetyl-1-pyrroline, 3-methylbutylacetate and ethyl hexanoate. Meanwhile, salivary enzymic degradation of odorants was more pronounced among the aldehydes, esters and thiols.
Food manufacturers are interested in developing emulsion-based products into nutritional foods by using beneficial oils, such as fish oil and virgin coconut oil (VCO). In this study, the physicochemical properties of a VCO oil-in-water emulsion was investigated and compared to other commercial oil-in-water emulsion products (C1, C2, C3, and C4). C3 exhibited the smallest droplet size of 3.25 µm. The pH for the emulsion samples ranged from 2.52 to 4.38 and thus were categorised as acidic. In a texture analysis, C2 was described as the most firm, very adhesive and cohesive, as well as having high compressibility properties. From a rheological viewpoint, all the emulsion samples exhibited non-Newtonian behaviour, which manifested as a shear-thinning property. The G'G'' crossover illustrated by the VCO emulsion in the amplitude sweep graph but not the other commercial samples illustrated that the VCO emulsion had a better mouthfeel. In this context, the VCO emulsion yielded the highest zeta potential (64.86 mV), which was attributed to its strong repulsive forces, leading to a good dispersion system. C2 comprised the highest percentage of fat among all emulsion samples, followed by the VCO emulsion, with 18.44% and 6.59%, respectively.
Our preliminary screening had shown that the curcumin derivative [2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone] or BDMC33 exhibited improved anti-inflammatory activity by inhibiting nitric oxide synthesis in activated macrophage cells. In this study, we further investigated the anti-inflammatory properties of BDMC33 on PGE(2 )synthesis and cyclooxygenase (COX) expression in IFN-γ/LPS-stimulated macrophages. We found that BDMC33 significantly inhibited PGE(2) synthesis in a concentration-dependent manner albeit at a low inhibition level with an IC(50) value of 47.33 ± 1.00 µM. Interestingly, the PGE(2) inhibitory activity of BDMC33 is not attributed to inhibition of the COX enzyme activities, but rather BDMC33 selectively down-regulated the expression of COX-2. In addition, BDMC33 modulates the COX expression by sustaining the constitutively COX-1 expression in IFN-γ/LPS-treated macrophage cells. Collectively, the experimental data suggest an immunodulatory action of BDMC33 on PGE(2) synthesis and COX expression, making it a possible treatment for inflammatory disorders with minimal gastrointestinal-related side effects.
A series of novel dimethoxyindanone embedded spiropyrrolidines were synthesized in ionic liquid, [bmim]Br and were evaluated for their inhibitory activities towards cholinesterases. Among the spiropyrrolidines, compound 4f exhibited the most potent activity with an IC50 value of 1.57 µM against acethylcholinesterase (AChE). Molecular docking simulation for the most active compound was employed with the aim of disclosing its binding mechanism to the active site of AChE receptor.
A new 4alpha-methyl sterol, 4alpha-methyl-ergosta-6,8(14),22E-triene-3beta-ol (1), was isolated along with cholesterol from a Nephthea sp. Bornean soft coral The structure of compound 1 was elucidated on the basis of spectroscopic analysis and comparison of the data with those of the related compounds.
A new abietene diterpene, kaempfolienol (5S,6S,7S,9S,10S,11R,13S-abiet-8(14)-enepenta-6,7,9,11,13-ol, 1), was isolated from a rhizome extract of Kaempferia angustifolia Rosc. along with the known compounds crotepoxide, boesenboxide, zeylenol, 2'-hydroxy-4,4',6'-trimethoxychalcone, (24S)-24-methyl-5α-lanosta-9(11),25-dien-3β-ol, β-sitosterol and β-sitosterol-3-O-β-D-glucopyranoside. The structures of all compounds were elucidated on the basis of mass spectroscopic and NMR data. Zeylenol (2), the major constituent of the plant, was derivatized into diacetate, triacetate and epoxide derivatives through standard organic reactions. The cytotoxic activity of compounds 1, 2 and the zeylenol derivatives was evaluated against the HL-60, MCF-7, HT-29 and HeLa cell lines.
Six populations of Laurencia nangii were found to produce three bromoallenes; dihydroitomanallene B (1), itomanallene B (2) and pannosallene (3). Prior to this report, L. nangii were only known to produce C(15)-acetogenins with acetylene functionality. This could be regarded as a new chemical race of L. nangii. The compound structures were elucidated on the basis of spectroscopic analysis and comparison with those previously reported in literature. Compound 1, dihydroitomanallene B, was isolated as a new compound representing a minor variation of itomanallene B (2).
A new cembrane diterpene, 6-acetoxy-7,8-epoxynephthenol acetate (1) was isolated along with a known compound, epoxynephthenol acetate (2), from the organic extract of a Bornean soft coral Nephthea sp. Their structures were elucidated on the basis of spectroscopic analyses and comparison with those previous literature data.
A new germacrane-type norsesquiterpenoid, 1-acetoxy-germacra-5E,10(14)-diene-4-one (1), as well as three known compounds, were isolated from the organic extracts of a Bornean soft coral Nephthea sp. Their structures were elucidated on the basis of spectroscopic data analysis.
Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4) nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.
The purification of thermo-acidic amylase enzyme from red pitaya (Hylocereus polyrhizus) peel for the first time was investigated using a novel aqueous two-phase system (ATPS) consisting of a thermo-separating copolymer and an organic solvent. The effectiveness of different parameters such as molecular weight of the thermo-separating ethylene oxide-propylene oxide (EOPO) copolymer and type and concentration of organic solvent on the partitioning behavior of amylase was investigated. In addition, the effects of phase components, volume ratio (VR), pH and crude load of purification factor and yield of amylase were evaluated to achieve the optimum partition conditions of the enzyme. In the novel ATPS method, the enzyme was satisfactorily partitioned into the polymer-rich top phase in the system composed of 30% (w/w) EOPO 2500 and 15% (w/w) 2-propanol, at a volume ratio of 1.94 and with a crude load scale of 25% (w/w) at pH 5.0. Recovery and recycling of components was also measured in each successive step of the ATPS process. The enzyme was successfully recovered by the method with a high purification factor of 14.3 and yield of 96.6% and copolymer was also recovered and recycled at a rate above 97%, making the method was more economical than the traditional ATPS method.
Our ongoing investigations on the stem bark of Mesua beccariana afforded a novel cyclodione coumarin, beccamarin, together with two known xanthones, mesuarianone, mesuasinone, two anthraquinones, 4-methoxy-1,3,5-trihydroxy-anthraquinone and 2,5-dihydroxy-1,3,4-trimethoxyanthraquinone and one coumarin, mammea A/AB. The structures were elucidated by 1D and 2D NMR and MS techniques.
A structural study of epoxidized natural rubber (ENR-50) and its cyclic dithiocarbonate derivative was carried out using NMR spectroscopy techniques. The overlapping (1)H-NMR signals of ENR-50 at δ 1.56, 1.68-1.70, 2.06, 2.15-2.17 ppm were successfully assigned. In this work, the C=S and quaternary carbon of cyclic dithiocarbonate. All other (1)H- and (13)C-NMR chemical shifts of the derivative remain unchanged with respect to the ENR-50.
An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2-, phenylalanine ammonia lyase (PAL) activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and Lipoxygenase inhibitory activity (LOX)] under four levels of foliar abscisic acid (ABA) application (0, 2, 4, 6 µM) for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2-, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC) were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05) and O2- (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05). This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.