Newest Methods and Approaches to Enhance the Performance of Optical Frequency-Domain Reflectometers.

In this review, we summarize the latest advances in the design of optical frequency-domain reflectometers (OFDRs), digital signal processing, and sensors based on special optical fibers. We discuss state-of-the-art approaches to improving metrological characteristics, such as spatial resolution, SNR, dynamic range, and the accuracy of determining back reflection coefficients. We also analyze the latest achievements in the OFDR-based sensors: the accuracy of spatial localization of the impact, the error in detecting temperatures, deformation, and other quantities, and the features of separate measurement of various physical quantities.

Detection and Recognition of Voice Commands by a Distributed Acoustic Sensor Based on Phase-Sensitive OTDR in the Smart Home Concept.

In recent years, attention to the realization of a distributed fiber-optic microphone for the detection and recognition of the human voice has increased, whereby the most popular schemes are based on φ-OTDR. Many issues related to the selection of optimal system parameters and the recognition of registered signals, however, are still unresolved. In this research, we conducted theoretical studies of these issues based on the φ-OTDR mathematical model and verified them with experiments.

Scientific Applications of Distributed Acoustic Sensing: State-of-the-Art Review and Perspective.

This work presents a detailed review of the development of distributed acoustic sensors (DAS) and their newest scientific applications. It covers most areas of human activities, such as the engineering, material, and humanitarian sciences, geophysics, culture, biology, and applied mechanics. It also provides the theoretical basis for most well-known DAS techniques and unveils the features that characterize each particular group of applications.

Resolution and contrast in terahertz pulse time-domain holographic reconstruction.

Here, we present a comprehensive study of the reconstruction quality in terahertz (THz) pulse time-domain holography. We look into single wavelength reconstructions, as well as broadband recovery enabled by the ultrabroadband nature of radiation and coherent detection enabled by electro-optic or photoconductive sensing. We demonstrate the transverse resolution dependence for amplitude and phase objects on the solid angle of the inline recorded time-domain THz hologram, and then turn to the contrast of reconstructed binary amplitude objects, and further to longitudinal resolution of phase objects.

[Successful treatment of bradyarrhythmia associated with obstructive sleep apnea syndrome by continuous positive airway pressure].

Obstructive Sleep Apnea Syndrome (OSAS) is an additional independent factor of growth of cardiovascular mortality. Special role disturbances of respiration during sleep play in development of nocturnal cardiac arrhythmias. Approaches to correction of OSAS associated nocturnal bradyarrhythmias have substantially changed during recent years.

Interfacial behavior of n-decane bound to weakly hydrated silica gel and nanosilica over a broad temperature range.

The interfacial and temperature behavior of n-decane bound to weakly hydrated nanosilica A-400 (initial, heated, or compacted) or silica gel Si-60 was studied using low-temperature (1)H NMR spectroscopy applied to static samples that allowed us to observe signals only of mobile decane and unfrozen water molecules. For deeper insight into the phenomena studied, interactions of n-decane, 1-decanol, and water with a set of nanosilicas and silica gels were analyzed using DSC and thermoporometry. Both NMR and DSC results demonstrated that during heating of frozen samples at a heating rate of 5 K/min a portion of decane or decanol remained frozen at temperature higher than the freezing point of bulk liquid (Tf).

A randomized comparison of pulmonary vein isolation with versus without concomitant renal artery denervation in patients with refractory symptomatic atrial fibrillation and resistant hypertension.

Objectives: The aim of this prospective randomized study was to assess the impact of renal artery denervation in patients with a history of refractory atrial fibrillation (AF) and drug-resistant hypertension who were referred for pulmonary vein isolation (PVI).

Background: Hypertension is the most common cardiovascular condition responsible for the development and maintenance of AF. Treating drug-resistant hypertension with renal denervation has been reported to control blood pressure, but any effect on AF is unknown.

Ganglionated plexi ablation directed by high-frequency stimulation and complex fractionated atrial electrograms for paroxysmal atrial fibrillation.

Background: The effectiveness of ganglionated plexi (GP) ablation in patients with atrial fibrillation (AF) is ambiguous. Some researchers had already suggested that additional identification of complex fractionated atrial electrograms (CFAE) around the areas with a positive reaction to high-frequency stimulation (HFS) might improve the accuracy of GP's boundaries location, then enhancing the success rate of ablation. The purpose of this study was to assess the safety and efficacy of GP ablation directed by HFS and CFAE in patients with paroxysmal AF (PAF).

Hydrated phosphorus oxyacids alone and adsorbed on nanosilica.

Low-temperature (1)Н NMR spectroscopy was used to study states of water bound to phosphoric and phosphonic acids (phosporus oxyacids, POA) alone or adsorbed onto nanosilica OX-50 (specific surface area S(BET)=52 m(2)/g) or A-300 (S(BET)=297 m(2)/g). Concentrated solutions or weakly hydrated solid POA or dried silica/POA powders placed in CCl(4) medium are characterized by different temperature dependences of the chemical shift of the proton resonance (δ(H)) because of partial dissociation of PO-H bonds strongly affected by water amounts and temperature. NMR cryoporometry results show that both small water clusters and nanodomains are present at the interfaces of hydrated solid POA and silica/POA powders.

Use of an implantable monitor to detect arrhythmia recurrences and select patients for early repeat catheter ablation for atrial fibrillation: a pilot study.

Background: Catheter ablation of atrial fibrillation (AF) has proved effective in curing highly symptomatic patients with paroxysmal AF. The aim of this prospective, randomized study was to identify the optimal treatment of patients with AF recurrences after the first ablation.

Methods And Results: Two hundred eighty-six patients with paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions) and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic).

Ablation of paroxysmal and persistent atrial fibrillation: 1-year follow-up through continuous subcutaneous monitoring.

Background: The aim of this prospective observational study was to identify responders to ablation through continuous subcutaneous monitoring for 1 year after ablation in patients with paroxysmal atrial fibrillation (PAF) or persistent AF (PersAF).

Method: Patients with symptomatic drug refractory AF were enrolled. Real-time three-dimensional (3D) left atrium maps were reconstructed by using a nonfluoroscopic navigation system (CARTO, Biosense-Webster Inc.

Percutaneous epicardial ablation of ventricular tachycardia after failure of endocardial approach in the pediatric population with arrhythmogenic right ventricular dysplasia.

Background: Despite the high efficacy of catheter ablation of ventricular tachycardia (VT) in patients with arrhythmogenic right ventricular dysplasia (ARVD), in some patients, conventional endocardial ablation is ineffective. These failures could be explained by the presence of epicardial arrhythmogenic substrate. In these cases, a percutaneous epicardial ablation may be required.

Left atrial ablation at the anatomic areas of ganglionated plexi for paroxysmal atrial fibrillation.

Background: Modification of left atrial ganglionated plexi (GP) is a promising technique for the treatment of paroxysmal atrial fibrillation (AF) but its therapeutic efficacy is not established. This study aimed at evaluating the effectiveness of anatomic GP modification by means of an implantable arrhythmia monitoring device.

Methods: In 56 patients with paroxysmal AF, radiofrequency ablation at anatomic sites, where the main clusters of GP have been identified in the left atrium, was performed.

Ganglionated plexi ablation for longstanding persistent atrial fibrillation.

Aims: To study the potential efficacy of ganglionated plexi (GP) ablation in the setting of longstanding persistent atrial fibrillation (AF).

Methods And Results: Anatomic ablation at the areas of GP in the left atrium was performed in 89 patients with symptomatic, drug-refractory, persistent AF (71 men, 56 +/- 7 years of age). In 29 patients, a second procedure by means of circumferential pulmonary vein (PV) isolation was performed, and 5 of them were subjected to a third circumferential ablation.

Synthesis, cytotoxicity, antiviral activity and interferon inducing ability of 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines.

New 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines were synthesized with high yields using bromoethylisatin and 6-(2-bromoethyl)-6H-indolo[2,3-b]quinoxaline as intermediates. These compounds were screened for the cytotoxicity, antiviral activity and interferon inducing ability. It was shown, that tested 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines are low toxic potent interferon inducers and antivirals.

Selective ganglionated plexi ablation for paroxysmal atrial fibrillation.

Background: Selective ganglionated plexi (GP) ablation guided by high-frequency stimulation has been proposed for the treatment of paroxysmal atrial fibrillation (AF), but the efficacy of the method is not established.

Objective: This study sought to compare selective ablation of GP identified by high-frequency stimulation with extensive regional ablation targeting the anatomic areas of GP in patients with paroxysmal AF.

Methods: Eighty patients with paroxysmal AF (age 53 +/- 9 years) were randomized to undergo selective GP ablation or regional left atrial ablation at the anatomic sites of GP.

Molecular structures of regioisomeric 7-arylidene hexahydroindazoles from (1)H NMR spectra.

The structural characterization of two regioisomeric products of the interaction of 2,6-bis-(4-methoxybenzylidene)-3R-methylcyclohexanone with methyl hydrazine was achieved using (1)H NMR spectral data, including chemical shifts, coupling constants and results of COSY and nuclear overhauser effect (NOE) experiments. Configurations of the new chiral centers in the (3S,3aR,6R,7E)-7-(4-methoxybenzylidene)-3,4,5,7-hexahydro-3-(4-methoxyphenyl)-2,6-dimethyl- and 2,4-dimethyl-2H-indazoles were assigned on the basis of experimental data combined with molecular modeling by the density functional theory (DFT) method. The distinction in the helical twisting power of studied compounds under addition to a nematic liquid crystal is discussed on the basis of peculiarities of the molecular structures.

Successful epicardial catheter ablation of micro-reentrant ventricular tachycardia in a 14-year-old child.

The article describes successful epicardial catheter ablation of ventricular tachycardia using the transpericardial approach in a 14-year-old adolescent. Conventional mapping of endocardial surface revealed criteria consistent with subpericardial localization of arrythmogenic substrate. Epicardial mapping using a transpericardial approach enabled localization and successful elimination of the ventricular tachycardia on the lateral wall of the right ventricle.

Catheter ablation of left atrial ganglionated plexi for atrial fibrillation.

Radiofrequency ablation of pulmonary vein ostia does not provide complete and long-term elimination of atrial fibrillation. Combining this procedure with local radiofrequency application on sites with strong vagal reflexes results in partial parasympathetic denervation and increases the antiarrhythmic effect. A novel catheter-ablation technique to modify ganglionated plexi in the left atrium was assessed in 58 patients (mean age, 52.

Unusual properties of water at hydrophilic/hydrophobic interfaces.

The behaviour of water at mosaic hydrophilic/hydrophobic surfaces of different silicas and in biosystems (biomacromolecules, yeast cells, wheat seeds, bone and muscular tissues) was studied in different dispersion media over wide temperature range using 1H NMR spectroscopy with layer-by-layer freezing-out of bulk water (close to 273 K) and interfacial water (180 < T < 273 K), thermally stimulated depolarization current (TSDC) (90 < T < 270 K), infrared (IR) spectroscopy, and quantum chemical methods. Bulk water and water bound to hydrophilic/hydrophobic interfaces can be assigned to different structural types. There are (i) weakly associated interfacial water (1H NMR chemical shift delta(H) = 1.

Morphology and surface properties of fumed silicas.

Several series of fumed silicas and mixed fumed oxides produced and treated under different conditions were studied in gaseous and liquid media using nitrogen and water adsorption-desorption, mass spectrometry, FTIR, NMR, thermally stimulated depolarization current (TSDC), photon correlation spectroscopy (PCS), zeta potential, potentiometric titration, and Auger electron spectroscopy methods. Aggregation of primary particles and adsorption capacity (Vp) decrease and hysteresis loops of nitrogen adsorption-desorption isotherms becomes shorter with decreasing specific surface area (S(BET)). However, the shape of nitrogen adsorption-desorption isotherms can be assigned to the same type independent of S(BET) value.

[Study of alcohol binding with serum albumin by NMR spectra of frozen aqueous solutions].

Interaction of alcohols (methanol, glycerol, sorbitol) with human serum albumin (HSA) was studied by the use of NMR spectroscopy in frozen aqueous solutions. The amount of binding was shown to increase in the series methanol-glycerol-sorbitol, on this basis a suggestion is made that interaction of alcohols with HSA occurs due to the formation of hydrogen bonds in which the hydroxyl groups act as proton donors. It is found that the presence of albumin influences significantly the outcome of eutectics from a diluted methanol solution and glycerol solution, the temperature of eutectics decreases in case of methanol and increases in case of glycerol.