General spectral characteristics of human activity and its inherent scale-free fluctuations.

The scale-free nature of daily human activity has been observed in different aspects; however, the description of its spectral characteristics is incomplete. General findings are complicated by the fact that-although actigraphy is commonly used in many research areas-the activity calculation methods are not standardized; therefore, activity signals can be different. The presence of 1/f noise in activity or acceleration signals was mostly analysed for short time windows, and the complete spectral characteristic has only been examined in the case of certain types of them.

Using intra-breath oscillometry in obesity hypoventilation syndrome to detect tidal expiratory flow limitation: a potential marker to optimize CPAP therapy.

Background: Continuous positive airway pressure (CPAP) therapy has profound effects in obesity hypoventilation syndrome (OHS). Current therapy initiation focuses on upper airway patency rather than the assessment of altered respiratory mechanics due to increased extrapulmonary mechanical load.

Methods: We aimed to examine the viability of intra-breath oscillometry in optimizing CPAP therapy for OHS.

The Actigraphy-Based Identification of Premorbid Latent Liability of Schizophrenia and Bipolar Disorder.

(1) Background and Goal: Several studies have investigated the association of sleep, diurnal patterns, and circadian rhythms with the presence and with the risk states of mental illnesses such as schizophrenia and bipolar disorder. The goal of our study was to examine actigraphic measures to identify features that can be extracted from them so that a machine learning model can detect premorbid latent liabilities for schizotypy and bipolarity. (2) Methods: Our team developed a small wrist-worn measurement device that collects and identifies actigraphic data based on an accelerometer.

Respiratory Oscillometry in Newborn Infants: Conventional and Intra-Breath Approaches.

Background: Oscillometry has been employed widely as a non-invasive and standardized measurement of respiratory function in children and adults; however, limited information is available on infants.

Aims: To establish the within-session variability of respiratory impedance (Zrs), to characterize the degree and profile of intra-breath changes in Zrs and to assess their impact on conventional oscillometry in newborns.

Methods: 109 healthy newborns were enrolled in the study conducted in the first 5 postpartum days during natural sleep.

Intra-breath changes in respiratory mechanics assessed from multi-frequency oscillometry measurements.

. Recent studies in respiratory system impedance (Zrs) with single-frequency oscillometry have demonstrated the utility of novel intra-breath measures of Zrs in the detection of pathological alterations in respiratory mechanics. In the present work, we addressed the feasibility of extracting intra-breath information from Zrs data sets obtained with conventional oscillometry.

Detailed analysis and comparison of different activity metrics.

Actigraphic measurements are an important part of research in different disciplines, yet the procedure of determining activity values is unexpectedly not standardized in the literature. Although the measured raw acceleration signal can be diversely processed, and then the activity values can be calculated by different activity calculation methods, the documentations of them are generally incomplete or vary by manufacturer. These numerous activity metrics may require different types of preprocessing of the acceleration signal.

Limitations of ventricular pacing maneuvers to differentiate orthodromic reciprocating tachycardia from atrioventricular nodal reentry tachycardia.

Purpose: Various ventricular pacing maneuvers have been developed to differentiate orthodromic reciprocating tachycardia (ORT) from atrioventricular nodal reentry tachycardia (AVNRT). We aimed to evaluate the diagnostic value of ventricular pacing maneuvers in patients undergoing catheter ablation for AVNRT/ORT.

Methods: Sixty patients with supraventricular tachycardia (SVT) undergoing invasive EP study were included (ORT: 31, typical AVNRT: 18, atypical AVNRT: 11).

Effect of nasal airway nonlinearities on oscillometric resistance measurements in infants.

Oscillometric measurements of respiratory system resistance (R) in infants are usually made via the nasal pathways, which not only significantly contribute to overall R but also introduce marked flow (V')-dependent changes. We employed intrabreath oscillometry in casts of the upper airways constructed from head CT images of 46 infants. We examined oscillometric nasal resistance (R) in upper airway casts with no respiratory flow (R) and the effect of varying V' on R by simulating tidal breathing.

Analysis of a Pulse Rate Variability Measurement Using a Smartphone Camera.

Background: Heart rate variability (HRV) provides information about the activity of the autonomic nervous system. Because of the small amount of data collected, the importance of HRV has not yet been proven in clinical practice. To collect population-level data, smartphone applications leveraging photoplethysmography (PPG) and some medical knowledge could provide the means for it.

Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure.

Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance () and reactance () at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated and as functions of gas flow (') and volume () during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa.

Tidal changes in respiratory resistance are sensitive indicators of airway obstruction in children.

Rationale: Individual assessment of airway obstruction in preschool-age children requires sensitive and specific lung function methods with low demand of cooperation. Although the forced oscillation technique (FOT) is feasible in young children, conventional measurements of respiratory impedance (Zrs) have limited diagnostic power in individuals.

Objective: To find descriptors of within-breath Zrs that are sensitive indicators of airway obstruction during tidal breathing in children.

Random noise can help to improve synchronization of excimer laser pulses.

Recently, we have reported on a compact microcontroller-based unit developed to accurately synchronize excimer laser pulses (Mingesz et al. 2012 Fluct. Noise Lett.

Generalized Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system using arbitrary resistors.

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system has been introduced as a simple, very low cost and efficient classical physical alternative to quantum key distribution systems. The ideal system uses only a few electronic components-identical resistor pairs, switches and interconnecting wires-in order to guarantee perfectly protected data transmission. We show that a generalized KLJN system can provide unconditional security even if it is used with significantly less limitations.

Respiratory impedance in healthy unsedated South African infants: effects of maternal smoking.

Background And Objective: Non-invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been used in infants. The study aims to assess the use of the forced oscillation technique to measure the influence of antenatal exposures on respiratory mechanics in unsedated infants enrolled in a birth cohort study in Cape Town, South Africa.

Assessment of respiratory mechanics with forced oscillations in healthy newborns.

Background: Lung function data in healthy newborn infants are scarce largely due to lack of suitable techniques, although data for developmental and prenatal exposure studies are much needed. We have modified the forced oscillation technique (FOT) for the measurement of respiratory mechanical impedance (Zrs) in unsedated sleeping infants in the first 3 days of life.

Methods: Zrs was measured during 30-s epochs of quiet sleep in term neonates born via spontaneous vaginal delivery with a non-invasive FOT between 8 and 48 Hz.

Noise properties in the ideal Kirchhoff-Law-Johnson-Noise secure communication system.

In this paper we determine the noise properties needed for unconditional security for the ideal Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system using simple statistical analysis. It has already been shown using physical laws that resistors and Johnson-like noise sources provide unconditional security. However real implementations use artificial noise generators, therefore it is a question if other kind of noise sources and resistor values could be used as well.

Role of triggering pulmonary veins in the maintenance of sustained paroxysmal atrial fibrillation.

Background: Triggers from thoracic veins have been implicated not only in the initiation, but also in the perpetuation of paroxysmal atrial fibrillation (PAF). To investigate their role we studied the distribution and stability of dominant frequencies (DFs) during PAF and the response to isolation of the triggering pulmonary vein (PV).

Methods And Results: Triggering structures inducing PAF were identified during isoproterenol challenge in 26 patients (15 males, 55 ± 8.

Photosynthetic reaction centers/ITO hybrid nanostructure.

Photosynthetic reaction center proteins purified from Rhodobacter sphaeroides purple bacterium were deposited on the surface of indium tin oxide (ITO), a transparent conductive oxide, and the photochemical/-physical properties of the composite were investigated. The kinetics of the light induced absorption change indicated that the RC was active in the composite and there was an interaction between the protein cofactors and the ITO. The electrochromic response of the bacteriopheophytine absorption at 771 nm showed an increased electric field perturbation around this chromophore on the surface of ITO compared to the one measured in solution.

Kinetic bacteriochlorophyll fluorometer.

A pump and probe fluorometer with a laser diode as single light source has been constructed for measurement of fast induction and relaxation of the fluorescence yield in intact cells, chromatophores and isolated reaction centers of photosynthetic bacteria. The time resolution of the fluorometer is limited by the repetition time of the probing flashes to 20 micros. The apparatus offers high sensitivity, excellent performance and can become a versatile device for a range of demanding applications.

Respiratory effects on the reproducibility of cardiovascular autonomic parameters.

The aim of this study was to assess the influence of breathing pattern on the reproducibility of the most commonly used heart rate and blood pressure variability parameters and baroreflex indices. 5-5 min ECG and blood pressure recordings were made and repeated for 10 healthy volunteers in supine rest on 10 consecutive days during spontaneous and 6 min(-1) patterned breathing. We investigated the following parameters: mean RR interval (RRI); the standard deviation of RR intervals (SDRR); the root mean square of successive differences in RRI (RMSSD); the percentage of RRIs which differed by 50% from the proceeding RRI (PNN50); mean systolic arterial pressure (SAP); the standard deviation of SAP (SAP SD); mean mean arterial pressure (MAP); mean diastolic blood pressure (DAP) and baroreflex indices from spontaneous sequence method (upBRS and downBRS) and from cross spectral analysis (LF alpha, HF alpha).

[Haemodynamic instability induced by carotid stent implantation].

Unlabelled: Intravascular stent implantation is an attractive therapy for carotid artery stenosis. Severe complications of the interventional procedure however include stroke and death.

Aims: It has been suggested, that episodes of temporary bradycardia and hypotension upon balloon inflation could be related to adverse outcome.

Characterization of polypyrrole-silver nanocomposites prepared in the presence of different dopants.

Conducting polypyrrole (PPy) powder synthesized by using FeCl3 x 6 H2O and/or Fe(NO3)3 oxidants was impregnated in silver salt solutions. The stability and decomposition of the material was followed by thermogravimetric measurements. The total silver content was determined by atom absorption spectroscopy (ICP-AAS).

Human autonomic responses to blood donation.

In order to characterize autonomic responses to acute volume loss, supine ECG, blood pressure (BP) and uncalibrated breathing signal (UBS) recordings were taken before and after blood donation in 48 healthy volunteers. Time and frequency domain parameters of RR interval (RRI), BP and UBS variability were determined. Baroreflex gain was calculated by the technique of the spontaneous sequences and cross-spectral analysis.

Effects of noise on the intensity of distortion product otoacoustic emissions.

Distortion product otoacoustic emission (DPOAE) is a widely used differential diagnostic method for diagnosing inner ear disorders. It provides us information on the condition of the outer hearing cells (OHCs). Otoacoustic emission occurs only when the OHCs are functioning normally.