Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocytes, chondrocytes, osteoblasts, melanocytes, macrophages, lung fibroblasts, and embryonic fibroblasts. These cells differed in several properties, and hence were a good representative sample of cells that would be targeted for expression and delivery of therapeutic genes in vivo. The efficiency of gene delivery in all these cells was enhanced using polyethylenimine-coated polyMAG magnetic nanoparticles, and the rates (17–84.2%) surpassed those previously achieved using other methods, especially in cells that are difficult to transfect. The application of permanent and pulsating magnetic fields significantly enhanced the transfection efficiencies in synoviocytes, chondrocytes, osteoblasts, melanocytes and lung fibroblasts, within 5 min of exposure to these magnetic fields. This is an added advantage for future in vivo applications, where rapid gene delivery is required before systemic clearance or filtration of the gene vectors occurs.     

Analytic study of multiserver buffers with two-state Markovian arrivals and constant service times of multiple slots

In this paper, we study the behavior of a discrete-time multiserver buffer system with infinite buffer size. Packets arrive at the system according to a two-state Markovian arrival process. The service times of the packets are assumed to be constant, equal to multiple slots. The behavior of the system is analyzed by means of an analytical technique based on probability generating functions (PGF’s). Explicit expressions are obtained for the PGF’s of the system contents and the packet delay. From these, the mean values, the variances and the tail distributions of the system contents and the packet delay are calculated. Numerical examples are given to show the influence of various model parameters on the system behavior.     

Preprocessing of ion mobility spectra by lognormal detailing and wavelet transform

This study has developed an efficient preprocessing strategy for ion mobility spectrometry (IMS) data allowing for improved peak clarity and comparability of different measurements. Using the discrete wavelet transform for data compression and denoising, and fitting a lognormal function to the strong tailing of the reactant ion peak (RIP), enables a data reduction to 25% or less, a significant increase of the signal-to-noise ratio, and the successful elimination of the RIP tailing. The preprocessing of breath measurements obtained by coupling an IMS to a gaschromatographic column, has resulted in the desired outcome of smooth peaks lying on a common base level. These results are transferable to other applications of one- and two-dimensional separations with IMS or instrumentations generating a similar data structure.     

Highly stereoselective De-Novo synthesis of protected 2-amino-3-C-methyl-2,3-dideoxy-d-altrose

A new strategy for the stereoselective synthesis of 2-amino-2-deoxy-aldoses is described. Therefore epoxy carbamates are reacted with isocyanates to furnish urethanes, which will form the title compounds with high diastereoselectivities under basic conditions and O,O-migration of the carbamoyl group.     

Distinction between surface hydroxyl and ether groups on boron-doped diamond electrodes using a chemical approach

While it is clearly established that oxidation of as-grown boron-doped diamond (BDD) interfaces results in the introduction of different surface oxygen functions such as ether, carbonyl and hydroxyl groups, there is no reported approach which can clearly distinguish between the different surface functions. For further surface functionalization, it is important to quantify the presence of each group on the diamond surface. In this paper, the presence and amount of surface hydroxyl groups is identified using esterification of the COH groups with trifluoroacetic acid. The presence of CF₃ group in the acid allowed the identification and estimation of the amount of surface hydroxyl groups using X-ray photoelectron spectroscopy (XPS).