A study on stability analysis of atrial repolarization variability using ARX model in sinus rhythm and atrial tachycardia ECGs

© 2016 Elsevier Ireland Ltd Background The interaction between the PTa and PP interval dynamics from the surface ECG is seldom explained. Mathematical modeling of these intervals is of interest in finding the relationship between the heart rate and repolarization variability. Objective The goal of this paper is to assess the bounded input bounded output (BIBO) stability in PTa interval (PTaI) dynamics using autoregressive exogenous (ARX) model and to investigate the reason for causing instability in the atrial repolarization process. Methods Twenty-five male subjects in normal sinus rhythm (NSR) and ten male subjects experiencing atrial tachycardia (AT) were included in this study. Five minute long, modified limb lead (MLL) ECGs were recorded with an EDAN SE-1010 PC ECG system. The number of minute ECGs with unstable segments (N us ) and the frequency of premature activation (PA) (i.e. atrial activation) were counted for each ECG recording and compared between AT and NSR subjects. Results The instability in PTaI dynamics was quantified by measuring the numbers of unstable segments in ECG data for each subject. The unstable segments in the PTaI dynamics were associated with the frequency of PA. The presence of PA is not the only factor causing the instability in PTaI dynamics in NSR subjects, and it is found that the cause of instability is mainly due to the heart rate variability (HRV). C onclusion The ARX model showed better prediction of PTa interval dynamics in both groups. The frequency of PA is significantly higher in AT patients than NSR subjects. A more complex model is needed to better identify and characterize healthy heart dynamics

DELAMINATION PREDICTION IN DRILLING OF CFRP COMPOSITES USING ARTIFICIAL NEURAL NETWORK

Carbon fibre reinforced plastic (CFRP) materials play a major role in the applications of aeronautic, aerospace, sporting and transportation industries. Machining is indispensible and hence drilling of CFRP materials is considered in this present study with respect to spindle speed in rpm, drill size in mm and feed in mm/min. Delamination is one of the major defects to be dealt with. The experiments are carried out using computer numerical control machine and the results are applied to an artificial neural network (ANN) for the prediction of delamination factor at the exit plane of the CFRP material. It is found that ANN model predicts the delamination for any given set of machining parameters with a maximum error of 0.81% and a minimum error of 0.03%. Thus an ANN model is highly suitable for the prediction of delamination in CFRP materials

Evaluation of a suitable material for soft actuator through experiments and FE Simulations

Soft actuators are generally built to achieve extension, contraction, curling, or bending motions needed for robotic or medical applications. It is prepared with a cylindrical tube, braided with fibers that restrict the radial motion and produce the extension, contraction, or bending. The actuation is achieved through the input of compressed air with a different pressure. The stiffness of the materials controls the magnitude of the actuation. In the present study, Silastic-P1 silicone RTV and multi-wall carbon nanotubes (MWCNT) with reinforced silicone are considered for the evaluation. The dumbbell samples are prepared from both materials as per ASTM D412-06a (ISO 37) standard and their corresponding tensile strength, elongation at break, and tensile modulus are measured. The Ogden nonlinear material constants of respective materials are estimated and used further in the finite element analysis of extension, contraction, and bending soft actuators. It is observed that silicone RTV is better in high strain and fast response, whereas, silicone/MWCNT is better at achieving high actuation

Spatiotemporally and Sequentially-Controlled Drug Release from Polymer Gatekeeper-Hollow Silica Nanoparticles

Combination chemotherapy has become the primary strategy against cancer multidrug resistance; however, accomplishing optimal pharmacokinetic delivery of multiple drugs is still challenging. Herein, we report a sequential combination drug delivery strategy exploiting a pH-triggerable and redox switch to release cargos from hollow silica nanoparticles in a spatiotemporal manner. This versatile system further enables a large loading efficiency for both hydrophobic and hydrophilic drugs inside the nanoparticles, followed by self-crosslinking with disulfide and diisopropylamine-functionalized polymers. In acidic tumour environments, the positive charge generated by the protonation of the diisopropylamine moiety facilitated the cellular uptake of the particles. Upon internalization, the acidic endosomal pH condition and intracellular glutathione regulated the sequential release of the drugs in a time-dependent manner, providing a promising therapeutic approach to overcoming drug resistance during cancer treatment.ope

(R1500) Type-I Generalized Spherical Interval Valued Fuzzy Soft Sets in Medical Diagnosis for Decision Making

In the present communication, we introduce the concept of Type-I generalized spherical interval valued fuzzy soft set and define some operations. It is a generalization of the interval valued fuzzy soft set and the spherical fuzzy soft set. The spherical interval valued fuzzy soft set theory satisfies the condition that the sum of its degrees of positive, neutral, and negative membership does not exceed unity and that these parameters are assigned independently. We also propose an algorithm to solve the decision making problem based on a Type-I generalized soft set model. We introduce a similarity measure based on the Type-I generalized soft set model for two Type-I generalized spherical interval valued fuzzy soft sets and discuss its application in a medical diagnosis problem. Illustrative examples are mentioned to show that they can be successfully used to solve problems with uncertainties

Cloaking nanoparticles with protein corona shield for targeted drug delivery

Targeted drug delivery using nanoparticles can minimize the side effects of conventional pharmaceutical agents and enhance their efficacy. However, translating nanoparticle-based agents into clinical applications still remains a challenge due to the difficulty in regulating interactions on the interfaces between nanoparticles and biological systems. Here, we present a targeting strategy for nanoparticles incorporated with a supramolecularly pre-coated recombinant fusion protein in which HER2-binding affibody combines with glutathione-S-transferase. Once thermodynamically stabilized in preferred orientations on the nanoparticles, the adsorbed fusion proteins as a corona minimize interactions with serum proteins to prevent the clearance of nanoparticles by macrophages, while ensuring systematic targeting functions in vitro and in vivo. This study provides insight into the use of the supramolecularly built protein corona shield as a targeting agent through regulating the interfaces between nanoparticles and biological systems

Hochdurchsatz-Untersuchung von anorganisch-organischen Hybridmaterialien: Metall-Phosphonatobenzolsulfonate und Ni-basierte MOFs mit Schaufelrad-Baueinheiten

The focus of this Ph.D. work is to systematically investigate the formation of inorganic-organic hybrid materials with different metal ions and polyfunctional organic linkers. The synthesis and characterization of the materials were performed under solvothermal conditions employing high-throughput (HT) methods. The HT methods incorporate the parallelization of individual reactions in miniaturized Teflon® reactors and the subsequent characterization of the crystalline products via automated HT-XRPD analysis. The HT methods have enabled the rapid study of the influences of compositional and process parameters on the formation fields and helped to optimize the synthesis conditions. In the first part of the thesis, the reaction system M2+/H2O3PC6H4SO3H/ NaOH/H2O was investigated (M = Ni,Mg,Cu,Zn,Co,Fe,Mn,Sn,Cd,Sr, Pb and Ba). The evaluation of the metal-ion screening yielded six metal 4-phosphonatobenzenesulfonates with Cu2+, Sn2+ and Pb2+ ions. Further detailed investigation of the molar ratio metal salt : linker : NaOH has helped to pinpoint the specific formation fields of each compound. Various M-O-M polyhedra and clusters are observed in the crystal structures which lead to 2D or 3D networks, especially in copper-based structures. A mixed-linker copper phosphonatosulfonate was also obtained with the auxiliary ligand 4,4’-bipyridine which exhibits an interesting reversible structural transition upon de-/rehydration. The characterization of the metal phosphonatosulfonates was performed with X-ray powder and single crystal X-ray diffraction, magnetic susceptibility measurements, thermogravimetric (TG) analysis, energy-dispersive X-ray (EDX) and CHNS elemental analysis, infrared (IR) spectroscopy and scanning electron microscopy (SEM). The second part of the thesis deals with the discovery and characterization of porous nickel(II) based metal-organic frameworks containing paddle-wheel building units. The dimeric paddle-wheel units are comprised of Ni2+ ions that are coordinated by four equatorial R(COO)- groups and two axial terminal ligands. The reaction system Ni2+/R(COOH)3/ additive / solvent, with R = C6H3, 1,3,5-(C6H4)3C6H3, was systematically investigated through screening of nickel salts, organic bases and solvents at various reaction temperatures. Two nickel(II) based compounds with paddle-wheel units were obtained with 1,3,5- benzenetricarboxylic (H3BTC) and 4,4’,4’’-benzene-1,3,5-triyl-tris-benzoic acid (H3BTB). In addition, two pseudo-polymorphs with the framework composition [Ni2(BDC)2(DABCO)] (H2BDC = terephthalic acid, DABCO = 1,4-diazabicyclo[2.2.2]octane) were discovered. For the phase selective synthesis, the influence of conventional vs. microwave-assisted heating, DABCO amount, stirring, overall concentration and reaction temperature was examined in detail. After the optimization of synthesis conditions, the scale-up of all four nickel(II) paddle-wheel compounds was accomplished and all the compounds were characterized via sorption experiments, IR spectroscopy, elemental analysis, SEM measurements and TG analysis.Der Schwerpunkt dieser Doktorarbeit ist die systematische Untersuchung der Bildung anorganisch-organischer Hybridmaterialien mit verschiedenen Metallionen und polyfunktionellen organischen Linkern. Die Synthese und Charakterisierung der Materialien wurden unter solvothermalen Bedingungen mit Hilfe von Hochdurchsatz (HT)-Methoden durchgeführt. Die HT-Methoden umfassen die Parallelisierung der einzelnen Reaktionen in Miniatur-Teflon® Reaktoren und die anschließende Charakterisierung der kristallinen Produkte mittels automatisierter HT-XRPD Analyse. Diese Methoden ermöglichen die schnelle Untersuchung der Einflüsse von Edukt-Zusammensetzungen und Prozessparametern auf die Kristallbildung. Im ersten Teil dieser Dissertation wurde das Reaktionssystem M2+/H2O3PC6H4SO3H/NaOH/H2O (M = Ni,Mg,Cu,Zn, Co,Fe,Mn,Sn,Cd,Sr,Pb and Ba) erforscht. Die Auswertung des Metallion-Screenings ergab sechs Metall-4-phosphonatobenzolsulfonate mit Cu2+, Sn2+ and Pb2+-Ionen. Weitere detaillierte Untersuchungen bei denen das molare Verhältnis Metallsalzen : Linker : NaOH untersucht wurde, half bei der Bestimmung der spezifischen Phasenbildungsbereiche jeder Verbindung. Unterschiedliche M-O Polyeder und M-O-M Cluster wurden in den Kristallstrukturen beobachtet, die zur Bildung von 2D oder 3D M-O Netzwerken geführt haben, insbesondere in den Kupfer-basierten Verbindungen. Ein Misch-Linker Cu-Phosphonatosulfonat wurde auch mit 4,4’-Bipyridin als Co-Ligand erhalten, das eine reversible Strukturumwandlung unter De-/Rehydratisierung aufweist. Die Charakterisierung der Metallphosphonatosulfonate wurde mittels Röntgenpulver- und Einkristallröntgenbeugung, Magnetsuszeptibilitätsmessungen, thermogravimetrischer Analyse (TGA), energiedispersiver Röntgenspektroskopie (EDX), CHNS Elementaranalyse, Infrarotspektroskopie (IR) und Rasterelektronmikroskopie (REM) durchgeführt. Der zweite Teil dieser Arbeit befasst sich mit der Entdeckung und Charakterisierung poröser Nickel(II)-basierter metall-organischer Gerüstverbindungen mit Schaufelrad-Baueinheiten. Die Schaufelrad-Dimere bestehen aus Ni2+-Ionen, die von vier äquitorialen R(COO)- Gruppen und zwei axialen Liganden umgeben sind. Das Reaktionssystem Ni2+/R(COOH)3/Additiv/Lösungsmittel, mit R = C6H3, 1,3,5-(C6H4)3C6H3, wurde systematisch durch Screening von Nickelsalzen, organischen Basen und Lösungsmitteln bei verschiedenen Reaktionstemperaturen untersucht. Zwei nickelbasierte Verbindungen mit Schaufelrad-Einheiten wurden mit 1,3,5-Benzoltricarbonsäure (H3BTC) and 4,4’,4’’-Benzol-1,3,5-triyl-trisbenzoesäure (H3BTB) erhalten. Zusätzlich wurden zwei Pseudopolymorphe mit der Gerüstzusammensetzung [Ni2(BDC)2(DABCO)] (H2BDC = Terephthalsäure, DABCO = 1,4-diazabicyclo[2.2.2]oktan) entdeckt. Die Optimierung der Reaktionsbedingungen führte zu einphasigen Produkten. Dazu wurde der Einfluss der Heizmethode (konventionelle vs. Mikrowellen-unterstützte Synthese), die DABCO-Menge, das Rühren, die Gesamtkonzentration und die Reaktionstemperaturen untersucht. Nach der Optimierung der Synthese, konnten alle vier Nickel(II)-Verbindungen, die Schaufelrad-Baueinheiten enthalten, in größeren Mengen hergestellt und ausführlich mittels Sorptionsmessung, IR-Spektroskopie, Elementaranalyse, REM und thermogravimetrischer Analyse charakterisiert werden