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A patch microstrip antenna with an inverted-V ground plane capable of improving radiation performance for a wireless local area network (WLAN) access point in the 2.4-GHz band is presented. By using a feeding structure composed of a step-shaped feeding strip in the air substrate and a coplanar strip in the narrow radiating patch, the proposed antenna can reduce cross-polarisation radiation (less than -20 dB) for frequencies across the 2.4 GHz WLAN band. The inverted-V ground plane comprises a narrow central ground portion for setting the 50 Ω subminiature version (SMA) connector for the patch antenna and two bent ground portions to control the broadening of the antenna's horizontal radiation pattern. By selecting the proper dimensions, the proposed antenna can have a wide horizontal radiation pattern of about 152° (3 dB beamwidth) with vertical polarisation, which is very suitable for WLAN access-point applications where uniform radiation in one direction or one half-space is required. Experimental results of a constructed prototype suitable for application in the 2.4 GHz WLAN access point are presented and discussed. [ABSTRACT FROM AUTHOR]

A compact patch antenna suitable for mounting above a conducting plate for WLAN operation in the 2.4 GHz band is presented. It is demonstrated that, by introducing a supporting metal plate connected to the antenna ground below, the proposed antenna in free space can easily be mounted at the corner of a conducting plate of various dimensions without rapidly deteriorating the antenna bandwidth. With a compact size of 20×20×6 mm, the antenna can be placed very close to a conducting plate of side length varied from 20 to 200 mm for application in a PC peripheral device. [ABSTRACT FROM AUTHOR]

Objective. Sleep apnea is a common sleep breathing disorder that can significantly decrease sleep quality and have major health consequences. It is diagnosed based on the apnea hypopnea index (AHI). This study explored a novel, generalized algorithm for the automatic diagnosis of sleep apnea employing airflow (AF) and oximetry (SpO2) signals. Approach. Of the 988 polysomnography records, 45 were randomly selected for developing the automatic algorithm and the remainder 943 for validating purposes. The algorithm detects apnea events by a per-sample encoding process applied to the peak excursion of AF signal. Hypopnea events were detected from the per-sample encoding of AF and SpO2 with an adjustment to time lag in SpO2. Total recording time was automatically processed and optimized for computation of total sleep time (TST). Total number of detected events and computed TST were used to estimate AHI. The estimated AHI was validated against the scored data from the Sleep Heart Health Study. Main results. Intraclass correlation coefficient of 0.94 was obtained between estimated and scored AHIs. The diagnostic accuracies were 93.5%, 92.4%, and 96.6% for AHI cut-off values of ≥5, ≥15, and ≥30 respectively. The overall accuracy for the combined severity categories (normal, mild, moderate, and severe) and kappa were 83.4% and 0.77 respectively. Significance. This new automatic technique was found to be superior to the other existing methods and can be applied to any portable sleep devices especially for home sleep apnea tests. [ABSTRACT FROM AUTHOR]

Objective. Sleep apnea significantly decreases the quality of life. The apnea hypopnea index (AHI) is the main indicator for sleep apnea diagnosis. This study explored a novel automatic algorithm to diagnose sleep apnea from nasal airflow (AF) and pulse oximetry (SpO2) signals. Approach. Of the 988 polysomnography (PSG) records from the sleep heart health study (SHHS), 45 were randomly selected for the development of an algorithm and the remainder for validation (n = 943). The algorithm detects apnea events by a digitization process, following the determination of the peak excursion (peak-to-trough amplitude) from AF envelope. Hypopnea events were determined from the AF envelope and oxygen desaturation with correction to time lag in SpO2. Total sleep time (TST) was estimated from an optimized percentage of artefact-free total recording time. AHI was estimated from the number of detected events divided by the estimated TST. The estimated AHI was compared to the scored SHHS data for performance evaluation. Main results. The validation showed good agreement between the estimated and scored AHI (intraclass correlation coefficient of 0.95 and mean ±95% limits of agreement of −1.6 ±12.5 events h−1). The diagnostic accuracies were found: 90.7%, 91%, and 96.7% for AHI cut-off ≥5, ≥15, and ≥30 respectively. Significance. The new algorithm is accurate over other existing methods for the automatic diagnosis of sleep apnea. It is applicable to any portable sleep screeners especially for the home diagnosis of sleep apnea. [ABSTRACT FROM AUTHOR]

Context and objectives. Synthetic cannabinoids are illegal drugs of abuse known to cause adverse neurologic and sympathomimetic effects. They are an emerging health risk: 11% of high school seniors reported smoking them during the previous 12 months. We describe the epidemiology of a toxicologic syndrome of acute kidney injury associated with synthetic cannabinoids, review the toxicologic and public health investigation of the cluster, and describe clinical implications of the cluster investigation. Materials and methods. Case series of nine patients affected by the toxicologic syndrome in Oregon and southwestern Washington during May-October 2012. Cases were defined as acute kidney injury (creatinine > 1.3 mg/dL) among persons aged 13-40 years without known renal disease who reported smoking synthetic cannabinoids. Toxicology laboratories used liquid chromatography and time-of-flight mass spectrometry to test clinical and product specimens for synthetic cannabinoids, their metabolites, and known nephrotoxins. Public health alerts informed clinicians, law enforcement, and the community about the cluster and the need to be alert for toxidromes associated with emerging drugs of abuse. Results. Patients were males aged 15-27 years (median, 18 years), with intense nausea and flank or abdominal pain, and included two sets of siblings. Peak creatinine levels were 2.6-17.7 mg/dL (median, 6.6 mg/dL). All patients were hospitalized; one required dialysis; none died. No alternate causes of acute kidney injury or nephrotoxins were identified. Patients reported easily purchasing synthetic cannabinoids at convenience, tobacco, and adult bookstores. One clinical and 2 product samples contained evidence of a novel synthetic cannabinoid, XLR-11 ([1-(5-fluoropentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone). Discussion and conclusion. Whether caused by direct toxicity, genetic predisposition, or an as-yet unidentified nephrotoxin, this association between synthetic cannabinoid exposure and acute kidney injury reinforces the need for vigilance to detect new toxicologic syndromes associated with emerging drugs of abuse. Liquid chromatography and time-of-flight mass spectrometry are useful tools in determining the active ingredients in these evolving products and evaluating them for toxic contaminants. [ABSTRACT FROM AUTHOR]

A technique that can reliably monitor exercise intensity plays an important role for the effectiveness and safety of an exercise prescription. A universal algorithm for the recursive estimation of exercise rate during a variety of aerobic exercises using measurements from a body-mounted triaxial accelerometer (TA) is proposed. Information about the type of exercise is not required by the algorithm and the TA can be mounted at the same location regardless of the exercise type. The algorithm involves period detection and data fusion. Experimental results demonstrate that the algorithm is effective for common aerobic exercises. [ABSTRACT FROM AUTHOR]

A new compact patch antenna, which is arranged perpendicular to a circular ground plane, for WLAN operation is presented. The antenna consists mainly of one driven patch and one shorted parasitic patch, both of which wind along two concentric circles. A constructed prototype covering the 2.4 and 5 GHz WLAN bands is demonstrated. Good broadside radiation characteristics are obtained across the operating bands. Details of the proposed patch antenna and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]