530 research outputs found

    Developing the Effective Method of Spectral Harmonic Energy Ratio to Analyze the Arterial Pulse Spectrum

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    In this article, we analyze the arterial pulse in the spectral domain. A parameter, the spectral harmonic energy ratio (SHER), is developed to assess the features of the overly decreased spectral energy in the fourth to sixth harmonic for palpitation patients. Compared with normal subjects, the statistical results reveal that the mean value of SHER in the patient group (57.7 ± 27.9) is significantly higher than that of the normal group (39.7 ± 20.9) (P-value = .0066 < .01). This means that the total energy in the fourth to sixth harmonic of palpitation patients is significantly less than it is in normal subjects. In other words, the spectral distribution of the arterial pulse gradually decreases for normal subjects while it decreases abruptly in higher-order harmonics (the fourth, fifth and sixth harmonics) for palpitation patients. Hence, SHER is an effective method to distinguish the two groups in the spectral domain. Also, we can thus know that a “gradual decrease” might mean a “balanced” state, whereas an “abrupt decrease” might mean an “unbalanced” state in blood circulation and pulse diagnosis. By SHER, we can determine the ratio of energy distribution in different harmonic bands, and this method gives us a novel viewpoint from which to comprehend and quantify the spectral harmonic distribution of circulation information conveyed by the arterial pulse. These concepts can be further applied to improve the clinical diagnosis not only in Western medicine but also in traditional Chinese medicine (TCM)

    Long Bubble Penetration through Viscoelastic Fluids in a Suddenly Contracting and Expanding Tube

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    This study investigated the properties of long bubbles penetrating viscoelastic fluids in a suddenly contracting and expanding tube. Injection gas flow is controlled by a mass flow controller (MFC). Some of dimensionless parameters, such as the capillary number (Ca), the Reynolds number (Re), the fractional ratio (m), and the Weissenberg number (Wi), are discussed herein. The experimental results showed that bubble velocity, Ca, and Wi increase as shear viscosity increases under a constant gas flow by MFC. However, as shear viscosity increases, bubble diameter decreases, and m increases. When gas flow is 200 mL/min and shear viscosity increases, the bubble front is sharper in the contraction tube, and the bubble front shape is blunter in the sudden expansion tube. When gas flow is 600 mL/min and shear viscosity increases, the bubble front is blunter in the contraction tube and exhibits a torch shape in the sudden expansion tube

    Drastic population fluctuations explain the rapid extinction of the passenger pigeon

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    To assess the role of human disturbances in species' extinction requires an understanding of the species population history before human impact. The passenger pigeon was once the most abundant bird in the world, with a population size estimated at 3-5 billion in the 1800s; its abrupt extinction in 1914 raises the question of how such an abundant bird could have been driven to extinction in mere decades. Although human exploitation is often blamed, the role of natural population dynamics in the passenger pigeon's extinction remains unexplored. Applying high-throughput sequencing technologies to obtain sequences from most of the genome, we calculated that the passenger pigeon's effective population size throughout the last million years was persistently about 1/10,000 of the 1800's estimated number of individuals, a ratio 1,000-times lower than typically found. This result suggests that the passenger pigeon was not always super abundant but experienced dramatic population fluctuations, resembling those of an "outbreak" species. Ecological niche models supported inference of drastic changes in the extent of its breeding range over the last glacial-interglacial cycle. An estimate of acorn-based carrying capacity during the past 21,000 y showed great year-to-year variations. Based on our results, we hypothesize that ecological conditions that dramatically reduced population size under natural conditions could have interacted with human exploitation in causing the passenger pigeon's rapid demise. Our study illustrates that even species as abundant as the passenger pigeon can be vulnerable to human threats if they are subject to dramatic population fluctuations, and provides a new perspective on the greatest human-caused extinction in recorded history

    Evidence for formation of multi-quantum dots in hydrogenated graphene.

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    We report the experimental evidence for the formation of multi-quantum dots in a hydrogenated single-layer graphene flake. The existence of multi-quantum dots is supported by the low-temperature measurements on a field effect transistor structure device. The resulting Coulomb blockade diamonds shown in the color scale plot together with the number of Coulomb peaks exhibit the characteristics of the so-called 'stochastic Coulomb blockade'. A possible explanation for the formation of the multi-quantum dots, which is not observed in pristine graphene to date, was attributed to the impurities and defects unintentionally decorated on a single-layer graphene flake which was not treated with the thermal annealing process. Graphene multi-quantum dots developed around impurities and defect sites during the hydrogen plasma exposure process.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

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    This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP) and heart rate variability (HRV). The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25 ± 4 yr; 29 men and 31 women) were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF) and high-frequency (HF) components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr) (P < .05), but the cold stress significantly increased AIr (P < .01). The spectral energy of RPP did not show any statistical difference in 0 ~ 10 Hz region under both conditions, but in the region of 10 ~ 50 Hz, there was a significant increase (P < .01) in the heat test and a significant decrease in the cold test (P < .01). The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10 ~ 50 Hz (SE10−50 Hz) but not in the region of 0 ~ 10 Hz (SE0−10 Hz). The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses

    A 64-week, multicenter, open-label study of aripiprazole effectiveness in the management of patients with schizophrenia or schizoaffective disorder in a general psychiatric outpatient setting

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    <p>Abstract</p> <p>Objective</p> <p>To evaluate the overall long-term effectiveness of aripiprazole in patients with schizophrenia in a general psychiatric practice setting in Taiwan.</p> <p>Methods</p> <p>This was a prospective, open-label, multicenter, post-market surveillance study in Taiwanese patients with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnosis of schizophrenia or schizoaffective disorder requiring a switch in antipsychotic medication because current medication was not well tolerated and/or clinical symptoms were not well controlled. Eligible patients were titrated to aripiprazole (5-30 mg/day) over a 12-week switching phase, during which their previous medication was discontinued. Patients could then enter a 52-week, long-term treatment phase. Aripiprazole was flexibly dosed (5-30 mg/day) at the discretion of the treating physicians. Efficacy was assessed using the Clinical Global Impression scale Improvement (CGI-I) score, the Clinical Global Impression scale Severity (CGI-S) score, The Brief Psychiatry Rating Scale (BPRS), and the Quality of Life (QOL) scale, as well as Preference of Medicine (POM) ratings by patients and caregivers. Safety and tolerability were also assessed.</p> <p>Results</p> <p>A total of 245 patients were enrolled and switched from their prior antipsychotic medications, and 153 patients entered the 52-week extension phase. In all, 79 patients (32.2%) completed the study. At week 64, the mean CGI-I score was 3.10 and 64.6% of patients who showed response. Compared to baseline, scores of CGI-S, QOL, and BPRS after 64 weeks of treatment also showed significant improvements. At week 12, 65.4% of subjects and 58.9% of caregivers rated aripiprazole as better than the prestudy medication on the POM. The most frequently reported adverse events (AEs) were headache, auditory hallucinations and insomnia. A total of 13 patients (5.3%) discontinued treatment due to AEs. No statistically significant changes were noted with respect to fasting plasma glucose, lipid profile, body weight, and body mass index after long-term treatment with aripiprazole.</p> <p>Conclusions</p> <p>Although the discontinuation rate was high, aripiprazole was found to be effective, safe and well tolerated in the long-term treatment of Taiwanese patients with schizophrenia who continued to receive treatment for 64 weeks.</p
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