Design and simulation of liquid infiltrated photonic crystal fibre in terahertz frequencies

Ethanol, methanol and water are polar solvents with similar physical properties albeit contrasting chemical properties. Therefore, it is essential to provide accurate and reliable methods for detecting these liquids. In this paper, a novel liquid infiltrated photonic crystal fibre for ethanol, methanol and water sensing is introduced. The novel structure is modelled, simulated and analysed in the terahertz (THz) region using a full vectorial finite element method. It is shown that the THz light, which is guided using modified total internal reflection, is confined within the infiltrated analytes with negligible losses. For the detection of infiltrated liquids at 1.6 THz operating frequency, the proposed fibre demonstrates high sensitivities up to 99.73% and confinement losses in the order of 10−4 dB/m. Manufacturing of the proposed fibre is feasible using existing fabrication technologies and it is envisaged that the fibre may provide a solution to existing challenges in detecting common polar solvents.

Synthesis of a hydrophilic derivative of ecdysterone and development of its water-soluble form

The article presents materials on the isolation of ecdysterone substance from medicinal plant raw materials Silene wolgensis (Hornem.) Bess. ex. Spreng (Volga smolyovka). For the first time, the optimization of the method for ecdysterone substance obtaining from the aboveground part of the superconcentrator of phytoecdysteroids of the Silene wolgensis was carried out and based on it a pilot industrial regulation for the isolation of ecdysterone and an encapsulated water-soluble form were developed. It was found, that the interaction of the substrate molecule and the clathrate forms a substance that can dissolve in water and other more polar solvents, thereby solving the problem of bioavailability of the main hydrophobic drug. The method developed for producing the substance ecdysterone and its water-soluble encapsulated with β-cyclodextrin form was implemented into production at the Karaganda pharmaceutical plant. NMR studies of changes in the chemical shifts of protons of substrates and receptors illustrated that ecdysterone interacts with β-cyclodextrin to form supramolecular inclusion complexes with stoichiometric composition of 1:1

A Fast-Response Driving Waveform Design Based on High-Frequency Voltage for Three-Color Electrophoretic Displays

Three-color electrophoretic displays (EPDs) have the characteristics of colorful display, reflection display, low power consumption, and flexible display. However, due to the addition of red particles, response time of three-color EPDs is increased. In this paper, we proposed a new driving waveform based on high-frequency voltage optimization and electrophoresis theory, which was used to shorten the response time. The proposed driving waveform was composed of an activation stage, a new red driving stage, and a black or white driving stage. The response time of particles was effectively reduced by removing an erasing stage. In the design process, the velocity of particles in non-polar solvents was analyzed by Newton’s second law and Stokes law. Next, an optimal duration and an optimal frequency of the activation stage were obtained to reduce ghost images and improve particle activity. Then, an optimal voltage which can effectively drive red particles was tested to reduce the response time of red particles. Experimental results showed that compared with a traditional driving waveform, the proposed driving waveform had a better performance. Response times of black particles, white particles and red particles were shortened by 40%, 47.8% and 44.9%, respectively.

Evaluation of Antioxidant Capacity and Antiproliferative Activity of Fruit Extract of Dry Figs (Ficus carica L.) on MDA MB-468 Cell Line

Fig (Ficus carica L.; Hindi: Anjeer) is one of the the earliest domesticated fruit. Present study investigates its antiproliferative activity against breast cancer (MDA MB-468) cells. Dry figs were mascerated in sixteen solvent-combinations of varying polartiy and extracts were assessed for antiproliferative activity in vitro. Extracts of moderatly polar solvents, particularly 80% aqueous-methanol extract showed maximum activity (IC50 = 17.9 mg IDF/ml). Antiproliferative efficacy of extracts was supported by respective total phenolic content (41-236 mg GAE/100g) and various antioxidant capacities; ABTS (14-354 µM TE/g), DPPH (18-460 µM TE/g), FRAP (28.7-66.5 µM FeSO4 equivalents/g), ORAC (7.9-32.8 µM TE/g), and superoxide radical scavenging activity. Flow cytometry analysis revealed that extracts of lower IC50 induce more cell death. Phenolic compounds (cyanidin 3-O-glucoside, quercetin 3-β-glucoside, rutin, trans-cinnamic acid, ellagic acid and ferulic acid) were analysed by UPLC-PDA technique and their concentrations in extracts were found to be negatively correlated with respective IC50 values. The negative correlation suggests the involvement of phenolics in fig’s antiproliferative mechanism. Therefore, the study advocates fig as a dietary component having anticancer potential.

Phytochemical analysis of commercially available Spirulina, their activities and Biosynthesis of Nanoparticles

Spirulina is used as dietary supplement in form of capsules and tablets. It is rich in Bioactive molecules and exhibits various activities. Commercially available Spirulina was collected. Extracts were prepared using various polar and non-polar solvents. The extracts were used for qualitative phytochemical analysis and to determine their Anti-Oxidant, Anti-Inflammatory and Anti-Arthritic activity. Phytochemicals like Tannin, Carbohydrates and Glycosides were present in all the extracts, while others were present only in few extracts. Biosynthesis of Nanoparticles was done by using the extract. Chloroform extract and Nanoparticles showed higher Anti-Oxidant activity, Ethanol extract showed higher Anti-Inflammatory activity and Chloroform extract showed higher Anti-Arthritic activity.

An Easily Synthesized Covalent Nanocage that Hosts Fullerenes in Multiple Charge States and Selectively Binds C70

Discrete nanocages provide a way to solubilize, separate, and tune the properties of molecular guests, including fullerenes and other aromatics. However, few such nanocages can be synthesized efficiently from inexpensive starting materials, limiting their practical utility. To address this limitation, we developed a new pyridinium-linked cofacial porphyrin nanocage (Cage4+) that can be prepared efficiently on a gram scale. NMR studies in CD3CN reveal that Cage4+ binds C60 and C70 with association constants >108 M-1 and complete selectivity for extracting C70 from mixtures of both fullerenes. The solubility of Cage4+ in polar solvents enabled electrochemical characterization of the host-guest complexes C60@Cage4+ and C70@Cage4+, finding that the redox properties of the encapsulated fullerenes are minimally affected despite the positive charge of the host. Complexes of the −1 and −2 charge states of the fullerenes bound in Cage4+ were subsequently characterized by UV-vis-NIR and NMR spectroscopies. The relatively easy preparation of Cage4+ and its ability to bind fullerenes without substantially affecting their redox properties suggests that C60@Cage4+ and C70@Cage4+ may be directly useful as solubilized fullerene derivatives.

Ultrafast intersystem crossing in xanthone from wavepacket dynamics

Most aromatic ketones containing first-row elements undergo unexpectedly fast intersystem crossing in few tens of picoseconds and a quantum yield close to unity. Among them, xanthone (9H-xanthen-9-one) possesses one of the fastest singlet-triplet rates of ~1.5 ps. The exact mechanism of this unusually fast transition is still under debate. Here, we perform the wavepacket dynamics of the photochemistry of xanthone in the gas phase and in polar solvents. We show that xanthone follows El-Sayed's rule for intersystem crossing. From the second singlet excited state, the mechanism is sequential: (i) an internal conversion between singlets 1pipi*-1npi* (85 fs), (ii) an intersystem crossing 1npi*-3pipi* (2.0 ps), and (iii) an internal conversion between triplets 3pipi*-3npi* (602 fs). Each transfer finds its origin in a barrierless access to electronic state intersections. These intersections are close to minimum energy structures, allowing for efficient transitions from the initial singlet state to the triplets.