Development of a Novel Electrochemical Biosensor for Detection and Discrimination of DNA Sequence and Single Base Mutation in dsDNA Samples Based on PNA‐dsDNA Hybridization – a new Platform Technology

In spite of the extensive attention paid on the development of various DNA detection strategies, very few studies have been reported regarding direct detection of DNA sequence and mutation in dsDNA. Here, we describe the feasibility of detection and discrimination of target DNA sequences and single base mutations (SBM) directly in double‐stranded oligonucleotides and PCR products without the need for denaturation of the target dsDNA samples. This goal was achieved by employing a peptide nucleic acid (PNA) chain, self‐assembled on the gold electrode as a probe, which binds to dsDNA and forms PNA‐dsDNA hybrid.     

Seeing the Unseen: Experimental Observation of Magnetic Anapole State Inside a High-Index Dielectric Particle

The existence of non-radiating electromagnetic sources attracts much attention in photonic community and gives rise to extensive discussions of various applications in lasing, medical imaging, sensing, and nonlinear optics. In this article, the existence of magnetic anapole states (or magnetic-type non-radiating sources) characterized by a suppressed magnetic dipole radiation in a dielectric cylindrical particle is theoretically predicted and experimentally demonstrated. The specific features of the magnetic anapole state under ideal conditions are identified, followed by a demonstration of how their existence can be detected in practical structures. The concept is valid in various frequency bands from visible range for nanoparticles to microwave range for millimeter size objects. The experimental study is performed in microwave frequency range which allows not only to measure the far-field (scattered field) characteristics, but also to probe the peculiar field profile directly inside the dielectric particle. The experimental results agree well with the analytical ones and pave the way to detect and identify nontrivial different-type anapole states.     

Analysis of Anti-Cancer and Anti-Inflammatory Properties of 25 High-THC Cannabis Extracts

Cannabis sativa is one of the oldest cultivated plants. Many of the medicinal properties of cannabis are known, although very few cannabis-based formulations became prescribed drugs. Previous research demonstrated that cannabis varieties are very different in their medicinal properties, likely due to the entourage effect—the synergistic or antagonistic effect of various cannabinoids and terpenes. In this work, we analyzed 25 cannabis extracts containing high levels of delta-9-tetrahydrocannabinol (THC). We used HCC1806 squamous cell carcinoma and demonstrated various degrees of efficiency of the tested extracts, from 66% to 92% of growth inhibition of cancer cells. Inflammation was tested by induction of inflammation with TNF-α/IFN-γ in WI38 human lung fibroblasts. The efficiency of the extracts was tested by analyzing the expression of COX2 and IL6; while some extracts aggravated inflammation by increasing the expression of COX2/IL6 by 2-fold, other extracts decreased inflammation, reducing expression of cytokines by over 5-fold. We next analyzed the level of THC, CBD, CBG and CBN and twenty major terpenes and performed clustering and association analysis between the chemical composition of the extracts and their efficiency in inhibiting cancer growth and curbing inflammation. A positive correlation was found between the presence of terpinene (pval = 0.002) and anti-cancer property; eucalyptol came second, with pval of 0.094. p-cymene and β-myrcene positively correlated with the inhibition of IL6 expression, while camphor correlated negatively. No significant correlation was found for COX2. We then performed a correlation analysis between cannabinoids and terpenes and found a positive correlation for the following pairs: α-pinene vs. CBD, p-cymene vs. CBGA, terpenolene vs. CBGA and isopulegol vs. CBGA. Our work, thus, showed that most of high-THC extracts demonstrate anti-cancer activity, while only certain selected extracts showed anti-inflammatory activity. Presence of certain terpenes, such as terpinene, eucalyptol, cymene, myrcene and camphor, appear to have modulating effects on the activity of cannabinoids.     

用于合成新型1,3,5-三芳基吡唑啉衍生物的磷钨酸铯盐的纳米塑形、模板合成及结构研究(英文)

The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW12O40(CsHPW) salt nanocrystal.We used 2D hexagonal SBA-15 silica as a template for the nanofabrication of CsHPW nanoparticles.Nanocast CsHPW materials are stable against leaching and colloidization in polar solvents.The catalytic performance of the nanocast CsHPW materi-als exceeded that of bulk Cs2.5H0.5PW12O40,which is the most active among the acidic HPW salts.A series of novel 1,3,5-triaryl-pyrazoline derivatives were synthesized by the reaction between chalcone and phenylhydrazine in high yield in the presence of CsHPW salt nanocrystals.     

Pencil Lead Electrode Modified with Hemoglobin Film as a Novel Biosensor for Nitrite Determination

In the present paper, the electrochemical reduction of nitrite at a hemoglobin modified pencil lead electrode (Hb/PLE) is described. The electrochemical properties of nitrite were studied by cyclic voltammetry and chronoamperometry. Results showed that the hemoglobin film has an excellent electrochemical activity towards the reduction of nitrite. By using voltammetric and chronoamperometric methods, α, n_α and n were calculated. Then the ability of the electrode for nitrite determination was investigated using differential pulse voltammetry. The electrocatalytic reduction peak currents were found to be linear with the nitrite concentration in the range from 10 to 220 µM with a detection limit of 5 µM. The relative standard deviation is 2 % for 3 successive determinations of a 100 µM nitrite solution. This modified electrode was successfully used for the detection of low amounts of NO₂^? in spinach sample and a spiked sample of tap water.     

Development of Voltammetric Sensor for Determination of Tryptophan Using MWCNTs‐modified Sol‐gel Electrode

In the present work, an electrochemical sensor was developed for simple and sensitive determination of tryptophan (Trp) using multi‐walled carbon nanotubes modified sol‐gel electrode (MWCNTs/SGE). The electrocatalytic oxidation of tryptophan was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the oxidation peak current of Trp at the MWCNTs/SGE was greatly improved compared with that of the bare SGE. Furthermore, at the MWCNTs/SGE, the anodic peak potential of Trp is shifted about 220 mV to more negative value indicated that modified electrode has better electrocatalytic activity for electro‐oxidation of Trp. The anodic peak currents increased linearly with the concentration of tryptophan in the range of 0.2 × 10^?6 to 15 × 10^?6 M with a detection limit of 0.139 × 10^?6 M (at an S/N = 3).     

Role of droplet bridging on the stability of particle-containing immiscible polymer blends

The effect of micron-sized hydrophobic calcium carbonate particles on the stabilization of polydimethylsiloxane (PDMS)/polyisobutylene (PIB) immiscible model blends is investigated in this study. The analytical splitting of bulk and liquid–liquid interface contributions from the droplet bridging one is successfully performed due to the negligible contribution of hydrophobic microparticles to the bulk rheology of phases. The presence of particles at the fluid–fluid interface is supported by wetting parameter calculation and verified by optical microscopy observations. Moreover, direct visualizations shows that particles are able to form clusters of droplets by simultaneously adsorbing at two fluid–fluid interfaces and glue-dispersed droplets together, probably due to the patchy interactions induced by heterogeneous distribution of particles along the interface. Rheological studies show that the flow-induced coalescence is slowed down upon addition of particles and almost suppressed with the addition of 4 wt% particles. The linear viscoelastic response is modeled to estimate interfacial tension by considering the contribution of particle-induced droplet aggregation in addition to bulk and droplet deformation ones. From linear and nonlinear viscoelastic responses, the improved stability of filled polymer blends is attributed to the interfacial rheology and/or the bridged structure of droplets, even though the interfacial area is not fully covered by particles. Furthermore, Doi–Ohta scaling relations are investigated by employing stress growth response upon step-up of shear flow.     

Natural Convection Induced by a Heated Vertical Plate Embedded in a Porous Medium with Transpiration: Local Thermal Non-equilibrium Similarity Solutions

This paper is concerned with the thermal non-equilibrium free convection boundary layer, which is induced by a vertical heated plate embedded in a saturated porous medium. The effect of suction or injection on the free convection boundary layer is also studied. The plate is assumed to have a linear temperature distribution, which yields a boundary layer of constant thickness. On assuming Darcy flow, similarity solutions are obtained for governing the steady laminar boundary layer equations. The reduced Nusselt numbers for both the solid and fluid phases are calculated for a wide range of parameters, and compared with asymptotic analyses.