ECG arrhythmia recognition via a neuro-SVM-KNN hybrid classifier with virtual QRS image-based geometrical features

In this study, a new supervised noise-artifact-robust heart arrhythmia fusion classification solution, is introduced. Proposed method consists of structurally diverse classifiers with a new QRS complex geometrical feature extraction technique.Toward this objective, first, the events of the electrocardiogram (ECG) signal are detected and delineated using a robust wavelet-based algorithm. Then, each QRS region and also its corresponding discrete wavelet transform (DWT) are supposed as virtual images and each of them is divided into eight polar sectors. Next, the curve length of each excerpted segment is calculated and is used as the element of the feature space. Discrimination power of proposed classifier in isolation of different Gold standard beats was assessed with accuracy 98.20%. Also, proposed learning machine was applied to 7 arrhythmias belonging to 15 different records and accuracy 98.06% was achieved. Comparisons with peer-reviewed studies prove a marginal progress in computerized heart arrhythmia recognition technologies.     

Effect of Amino Acid Substitutions on 70S Ribosomal Binding,Cellular Uptake,and Antimicrobial Activity of Oncocin Onc112

Proline-rich antimicrobial peptides (PrAMPs) are promising candidates for the treatment of infections caused by high-priority human pathogens. Their mode of action consists of (I) passive diffusion across the outer membrane, (II) active transport through the inner membrane, and (III) inhibition of protein biosynthesis by blocking the exit tunnel of the 70S ribosome. We tested whether in vitro data on ribosomal binding and bacterial uptake could predict the antibacterial activity of PrAMPs against Gram-negative and Gram-positive bacteria. Ribosomal binding and bacterial uptake rates were measured for 47 derivatives of PrAMP Onc112 and compared to the minimal inhibitory concentrations (MIC) of each peptide. Ribosomal binding was evaluated for ribosome extracts from four Gram-negative bacteria. Bacterial uptake was assessed by quantifying each peptide in the supernatants of bacterial cultures. Oncocin analogues with a higher net positive charge appeared to be more active, although their ribosome binding and uptake rates were not necessarily better than for Onc112. The data suggest a complex mode of action influenced by further factors improving or reducing the antibacterial activity, including diffusion through membranes, transport mechanism, secondary targets, off-target binding, intracellular distribution, and membrane effects. Relying only on in vitro binding and uptake data may not be sufficient for the rational development of more active analogues.     

New Efficient Synthesis of tRNA Related Adenosines Bearing the Hydantoin Ring (ct6A,ms2ct6A) by Intramolecular Cyclization of N6-(N-Boc-α-aminoacyl)-adenosine Derivatives

A novel and efficient way for the synthesis of N⁶-hydantoin-modified adenosines, which utilizes readily available N⁶-(N-Boc-α-aminoacyl)-adenosine derivatives, was developed. The procedure is based on the epimerization-free, Tf₂O-mediated conversion of the Boc group into an isocyanate moiety, followed by intramolecular cyclization. Using this method two recently discovered hydantoin modified tRNA adenosines, that is, cyclic N⁶-threonylcarbamoyl-adenosine ( ct⁶A ) and 2-methylthio-N⁶-threonylcarbamoyladenosine ( ms²ct⁶A ) were prepared in good yields.