Lipid-DNA conjugates for cell membrane modification,analysis, and regulation

ABSTRACT

Lipids and DNAs are two major building blocks of life. Interestingly, by chemically linking these two natural compounds together, synthetic lipid-DNA conjugates exhibit several attractive features for cell membrane studies. These lipid-DNA conjugates are amphiphilic macromolecules combining the cell membrane insertion capability of lipids with the properties of DNAs in precise hybridization and programmability. These supramolecular conjugates have demonstrated exciting applications from generating cell membrane nanopores to transmembrane cargo deliveries, and from analyzing cell membrane events to tissue engineering. In this review, we will discuss the design, structures, and biological applications of lipid-DNA conjugates, with an emphasis on their functions on live cell membranes. We expect, in the near future, significant advancement in our ability to understand, control, and apply these cell membrane-modified lipid-DNA conjugates.     

A Review on Bioengineering Approaches to Insulin Delivery: A Pharmaceutical and Engineering Perspective

Diabetes mellitus (DM) is the most prevalent non‐contagious disease, which has affected a large number of people all over the world. Among all treatments known to have a positive influence in the control of DM, insulin therapy is the most common and effective one. Nowadays, various methods of insulin delivery are under investigation, which are able to reach a plausible bioavailability with ignorable side effects instead of insulin injection. This article presents a comprehensive review of the insulin therapy approach with a focus on modified methods in insulin delivery strategies and current advances in engineered insulin delivery systems.     

Dissipation of carbendazim and its metabolites in cucumber using liquid chromatography tandem mass spectrometry

Currently, there is growing interest in the degradation pathways of organic contaminants such as pesticides. In the case of pesticides, the determination of metabolites in agricultural products and environment is necessary as some of them could present similar toxicity to or even higher toxicity than the parent compound. The development of analytical methodology for the identification and quantification of carbendazim fungicide and its metabolites in cucumber was studied. Cucumber (cucumis sativus) is a global food in terms of economic importance and nutritional quality. Careful optimisation of the liquid chromatography–mass spectrometry (LC-MS)/MS parameters was achieved in order to attain a fast separation with the best sensitivity. The detection was carried out on an Ion-Trap tandem mass spectrometer (MS/MS) by electrospray ionisation in positive ion mode (ESI+) with multiple reaction monitoring (MRM).     

Production of light olefins from methanol over modified H-ZSM-5: effect of metal impregnation in high-silica zeolite on product distribution

Research on Chemical Intermediates - Improvement of H-ZSM-5 catalyst to convert methanol to light olefins was studied in this research. High-silica H-ZSM-5 zeolite (Si/Al = 200)...     

Preparation and characterization of Fe3O4@Cu-β-CD as a hybrid magnetic catalyst for the synthesis of dihydropyrano[2,3-c]pyrazoles in H2O

Research on Chemical Intermediates - Fe3O4@Cu-β-CD is a hybrid composite with high catalytic activity. Easy separation with an external magnet and recyclability are the advantages of this...     

Modification of Multiple Knot $B$-Spline Wavelet for Solving (Partially) Dirichlet Boundary Value Problem

A construction of multiple knot B-spline wavelets has been given in [C. K. Chui and E. Quak, Wavelet on a bounded interval, In: D. Braess and L. L. Schumaker, editors. Numerical methods of approximation theory. Basel: Birkhauser Verlag; (1992), pp. 57-76]. In this work, we first modify these wavelets to solve the elliptic (partially) Dirichlet boundary value problems by Galerkin and Petrov Galerkin methods. We generalize this construction to two dimensional case by Tensor product space. In addition, the solution of the system discretized by Galerkin method with modified multiple knot B-spline wavelets is discussed. We also consider a nonlinear partial differential equation for unsteady flows in an open channel called Saint-Venant. Since the solving of this problem by some methods such as finite difference and finite element produce unsuitable approximations specially in the ends of channel, it is solved by multiple knot B-spline wavelet method that yields a very well approximation. Finally, some numerical examples are given to support our theoretical results.     

Reaction of Chalcones with Cellular Thiols. The Effect of the 4-Substitution of Chalcones and Protonation State of the Thiols on the Addition Process. Diastereoselective Thiol Addition

Several biological effects of chalcones have been reported to be associated with their thiol reactivity. In vivo, the reactions can result in the formation of small-molecule or protein thiol adducts. Both types of reactions can play a role in the biological effects of this class of compounds. Progress of the reaction of 4-methyl- and 4-methoxychalcone with glutathione and N-acetylcysteine was studied by the HPLC-UV-VIS method. The reactions were conducted under three different pH conditions. HPLC-MS measurements confirmed the structure of the formed adducts. The chalcones reacted with both thiols under all incubation conditions. The initial rate and composition of the equilibrium mixtures depended on the ratio of the deprotonated form of the thiols. In the reaction of 4-methoxychalcone with N-acetylcysteine under strongly basic conditions, transformation of the kinetic adduct into the thermodynamically more stable one was observed. Addition of S-protonated N-acetylcysteine onto the polar double bonds of the chalcones showed different degrees of diastereoselectivity. Both chalcones showed a Michael-type addition reaction with the ionized and non-ionized forms of the investigated thiols. The initial reactivity of the chalcones and the equilibrium composition of the incubates showed a positive correlation with the degree of ionization of the thiols. Conversions showed systematic differences under each set of conditions. The observed differences can hint at the difference in reported biological actions of 4-methyl- and 4-methoxy-substituted chalcones.     

The general analytical and numerical solution for the modified KdV equation with convergence analysis

We investigate the analytical and numerical solutions of the modified Kortweg de Vries equation by applying the idea of commutative hypercomplex mathematics, He's homotopy perturbation method as a simple particular procedure, and the Runge–Kutta discontinuous Galerkin methods. Moreover, we discuss at great length the convergence conditions for this equation by using the Banach fixed point theory, which could provide a good iteration algorithm. Finally, we compare the homotopy perturbation method with some standard ideas same as the Runge–Kutta discontinuous Galerkin method by some numerical illustrations. Copyright © 2012 John Wiley & Sons, Ltd.     

Estimation of natural gas contribution in indoor 222Rn concentration level in residential houses

Journal of Radioanalytical and Nuclear Chemistry - The effect of natural gas use on indoor radon concentrations was studied in the dwelling of two cities in Cyprus using an AlphaGUARD radon...     

AC electrokinetic isolation and detection of extracellular vesicles from dental pulp stem cells: Theoretical simulation incorporating fluid mechanics

Extracellular vesicles (EVs) are cell-derived nanoscale vesicles involved in intracellular communication and the transportation of biomarkers. EVs released by mesenchymal stem cells have been recently reported to play a role in cell-free therapy of many diseases. However, the demand for better research tools to replace the tedious conventional methods used to study EVs is getting stronger. EVs' manipulation using alternating current (AC) electrokinetic forces in a microfluidic device has appeared to be a reliable and sensitive diagnosis and trapping technique. Given that different AC electrokinetic forces may contribute to the overall motion of particles and fluids in a microfluidic device, EVs' electrokinetic trapping must be examined considering all dominant forces involved depending on the experimental conditions. In this paper, AC electrokinetic trapping of EVs using an interdigitated electrode arrays is investigated. A 2D numerical simulation incorporating the two significant AC electrokinetic phenomena (Dielectrophoresis and AC electroosmosis) has been performed. Theoretical predictions are then compared with experimental results and allow for a plausible explanation of observations inconsistent with DEP theory. It is demonstrated that the inconsistencies can be attributed to a significant extent to the contribution of the AC electroosmotic effect.