Band-phase-randomized surrogate data reveal high-frequency chaos in heart rate variability.

We propose a new band-phase-randomized surrogate data method to evaluate the chaotic dynamics in the high (HF) and low frequency (LF) bands of heart rate variability (HRV) in healthy subjects. The chaotic strength of normal HRV as assessed by a noise titration assay completely vanished when its power spectrum was phase-randomized over the entire frequency band or the HF band alone, but not the LF band alone. This finding confirms recent evidence that chaotic dynamics in normal HRV is ascribable mainly to the HF component, or respiratory sinus arrhythmia.

Automatic bone removal dual-energy CT angiography for the evaluation of intracranial aneurysms.

Purpose: To evaluate the diagnostic accuracy of dual-energy computed tomographic angiography (DE-CTA) in the detection of intracranial aneurysms and to determine whether DE-CTA provides adequate information to guide treatment choice.

Materials And Methods: Eighty patients (31 men and 49 women; mean [SD] ages of 52 [9] years) with spontaneous subarachnoid hemorrhage underwent DE-CTA. The performance of DE-CTA was compared with conventional CTA created from average weighted images and digital subtraction angiography (DSA).

Environmental management system vs green specifications: how do they complement each other in the construction industry?

Environmental Management System (EMS) has been one of the important tools for sustainable construction for around two decades. However, many issues concerning sustainable development have not been properly addressed, and there is a need for the introduction of green specifications to advance green performance in construction through contract management. This paper defines green specifications, identifies the reasons for adopting green specifications and highlights the environmental issues that may not be addressed by solely adopting EMS.

Mitochondrial monoamine oxidase-A-mediated hydrogen peroxide generation enhances 5-hydroxytryptamine-induced contraction of rat basilar artery.

Background And Purpose: We evaluated the role(s) of monoamine oxidase (MAO)-mediated H₂O₂ generation on 5-hydroxytryptamine (5-HT)-induced tension development of isolated basilar artery of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats.

Experimental Approach: Basilar artery (endothelium-denuded) was isolated for tension measurement and Western blots. Enzymically dissociated single myocytes from basilar arteries were used for patch-clamp electrophysiological and confocal microscopic studies.

Does ketogenic diet alter seizure sensitivity and cell loss following fluid percussion injury?

Traumatic brain injury (TBI) frequently leads to epilepsy. The process of epileptogenesis - the development of that seizure state - is still poorly understood, and effective antiepileptogenic treatments have yet to be identified. The ketogenic diet (KD) has been shown to be effective as an antiepileptic therapy, but has not been extensively tested for its efficacy in preventing the development of the seizure state, and certainly not within the context of TBI-induced epileptogenesis.

A versatile photochromic dithienylethene-containing β-diketonate ligand: near-infrared photochromic behavior and photoswitchable luminescence properties upon incorporation of a boron(III) center.

A versatile dithienylethene-containing β-diketonate ligand and its boron(III) compounds have been successfully synthesized. Upon photocyclization, the ligand shows a new absorption band at 630 nm with good fatigue resistance and high thermal stability. Incorporation of the boron center has been demonstrated to shift the photochromic behavior to the NIR region.

Hyperbranched alternating block copolymers using thiol-yne chemistry: materials with tuneable properties.

Alternating-block hyperbranched polymers were synthesized using the highly versatile thiol-yne reaction. Dimethyl acrylamide-styrene and tert-butyl acrylate-styrene polymers were prepared, with subsequent hydrolysis of the tert-butyl ester to acrylic acid. The dimethyl acrylamide-styrene hyperbranched polymers self-assembled into large aggregates, as did the acrylic acid-styrene system at low pH.

A picoampere A/D converter for biosensor applications.

Detection and analysis of biological and biochemical signals via compact sensor systems require low-power and compact analog-to-digital converter (ADC) systems. Here we present a highly sensitive flash current-mode ADC (IADC) design with resolution down to 15pA. The IADC's small-size and low-power capabilities allow integration for stand-alone biological or chemical microsensor applications.

Evaluation of anti-oxidant capacity of root of Scutellaria baicalensis Georgi, in comparison with roots of Polygonum multiflorum Thunb and Panax ginseng CA Meyer.

In Chinese communities, regular consumption of Chinese-medicated diets (CMD) (usually in the form of soup) is a traditional practice to promote health and prevent disease development. The overall improvement of health conditions is believed to be correlated with the anti-oxidant potentials of these herbs. Huangqin, roots of Scutellaria baicalensis Georgi (Lamiaceae), is one of the herbs commonly used in CMD.

14,15-Epoxyeicosatrienoic acid induces vasorelaxation through the prostaglandin EP(2) receptors in rat mesenteric artery.

Epoxyeicosatrienoic acids (EETs) induce vasorelaxation, probably through G protein-coupled receptors. The identity of these receptors is unclear, but it has been reported that EETs may bind to peroxisome proliferator activated receptors (PPARs) and E-prostanoid (EP) receptors. Therefore, we studied whether PPARs or EP receptors were involved in 14,15-EET-induced vasorelaxation.

An unusual cause of delirium.

Sleep disordered breathing (SDB) including obstructive sleep apnea (OSA), central sleep apnea (CSA), and Cheyne-Stokes breathing is common in patients with congestive heart failure (CHF). In a study of 81 males with an ejection fraction (EF) < 45%, 51% of patients had documented SDB with the majority of cases representing CSA. Studies suggest that SDB is an independent risk factor for increased morbidity and mortality in the setting of CHF.

The non-invasive and continuous estimation of cardiac output using a photoplethysmogram and electrocardiogram during incremental exercise.

Cardiac output (CO) monitoring is not only essential for critically ill patients in the hospital, but also for patients at home and those undergoing cardiopulmonary exercise testing. However, CO is difficult to monitor during daily activities and exercise. In this paper, we aim at developing a novel CO estimation method that can be used under these challenging conditions.

Bilateral lesions of pontine Kölliker-Fuse nuclei provoke apnea instead of apneusis in anesthetized adult rats.

The Kölliker-Fuse nucleus (KF) has been traditionally dubbed the "pneumotaxic center". Here, we report that lesions of KF nuclei of bilateral pons caused apnea (complete cessation of phrenic discharge) instead of apneusis in urethane-anesthetized, vagotomized, paralyzed and ventilated adult rats. After bilateral lesions of KF nuclei with the neuroexcitotoxin kainic acid, phrenic discharge disappeared and no spontaneous recovery of phrenic discharge was observed for up to 3 hours.

Paradoxical potentiation of exercise hyperpnea in congestive heart failure contradicts Sherrington chemoreflex model and supports a respiratory optimization model.

Congestive heart failure (CHF) patients suffer decreased exercise tolerance, yet they demonstrate an augmented ventilatory response to exercise such that P(aCO2) remains normal (isocapnic) from rest to maximal exercise in the face of increased pulmonary dead space (Fig. 1). On the other hand, the effect of a large external dead space is hypercapnic instead of isocapnic.

Homeostatic competition: evidence of a serotonin-gated spinoparabrachial pathway for respiratory and thermoregulatory interaction.

Control of breathing and thermoregulation are vital physiological functions for the maintenance of arterial blood gas and pH homeostasis and body temperature homeostasis, respectively. It is widely believed that these homeostatic regulation functions act independently of one another via certain set point or feedfoward/feedback control mechanisms that are specific to each system. Here, the notion of "homeostatic competition" is introduced to depict the interaction of the respiratory and thermal controllers in negotiating a minimum-work ventilatory pattern that is optimal for survival in the face of conflicting homeostatic objectives during thermal stress.

Abdominal drain causing early small bowel obstruction after laparoscopic colectomy.

We report a rare drain-related complication leading to small bowel obstruction after laparoscopic colectomy. An 82-year-old man developed small bowel obstruction on the second day after laparoscopic anterior resection. Emergency relaparoscopy found herniation of the small bowel mesentery into the side holes of the silicon intraabdominal drain, which led to a 90-degree acute turn of the small bowel and mechanical obstruction.

Analog integrated circuits design for processing physiological signals.

Analog integrated circuits (ICs) designed for processing physiological signals are important building blocks of wearable and implantable medical devices used for health monitoring or restoring lost body functions. Due to the nature of physiological signals and the corresponding application scenarios, the ICs designed for these applications should have low power consumption, low cutoff frequency, and low input-referred noise. In this paper, techniques for designing the analog front-end circuits with these three characteristics will be reviewed, including subthreshold circuits, bulk-driven MOSFETs, floating gate MOSFETs, and log-domain circuits to reduce power consumption; methods for designing fully integrated low cutoff frequency circuits; as well as chopper stabilization (CHS) and other techniques that can be used to achieve a high signal-to-noise performance.

Nucleic acid contamination of glycogen used in nucleic acid precipitation and assessment of linear polyacrylamide as an alternative co-precipitant.

Molecular-grade glycogen is widely used to recover nanogram or picogram quantities of DNA and RNA across molecular biology applications in the life sciences. As a result, its purity is critical to obtain reliable results. Using agarose gel electrophoresis, we detected pg/microL (DNA) to ng/microL (RNA) concentrations of nucleic acid in two of the nine glycogen samples obtained from commercial suppliers.

A novel method for the contactless and continuous measurement of arterial blood pressure on a sleeping bed.

Nighttime blood pressure (BP) is found to best predict the 5-year risk of cardiovascular death in comparison to daytime BP, BP measured over a 24-hour period and clinical BP. In view of this, a novel contactless system has been developed on a sleeping bed for the cuffless and continuous estimation of BP at night. Experiments were conducted on 11 subjects to evaluate the contactless system, particularly its performance compared to a contact system.

A novel method for assessing arterial stiffness by a hydrostatic approach.

Arterial stiffness is an important index for cardiovascular events. The objective of this study is to examine possible parameters related to arterial stiffness that can be estimated during simple arm movements. An experiment was conducted on 32 subjects divided into two groups, one with an age of 26+/-4 years old, and the other 61+/-9.

A protocol design for evaluation of wearable cuff-less blood pressure measuring devices.

This paper proposes one of the unique requirements in the validation protocol of the IEEE P1708 standard in assessing wearable cuff-less blood pressure (BP) measuring devices. Based on principles that are different from that of the conventional cuff-based devices, the cuff-less BP measurement approaches often require an individual calibration procedure. In this study, we used data from an experiment carried out on 28 subjects with a total of 139 sets of BP measurements as an example to show that breakdown of the performance evaluation of cuff-less devices according to the change of BP from the point of calibration is crucial for understanding and interpreting the overall accuracy of the device.

Fractal, entropic and chaotic approaches to complex physiological time series analysis: a critical appraisal.

A wide variety of methods based on fractal, entropic or chaotic approaches have been applied to the analysis of complex physiological time series. In this paper, we show that fractal and entropy measures are poor indicators of nonlinearity for gait data and heart rate variability data. In contrast, the noise titration method based on Volterra autoregressive modeling represents the most reliable currently available method for testing nonlinear determinism and chaotic dynamics in the presence of measurement noise and dynamic noise.

A biometric method to secure telemedicine systems.

Security and privacy are among the most crucial issues for data transmission in telemedicine systems. This paper proposes a solution for securing wireless data transmission in telemedicine systems, i.e.