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This article presents an ultrabroadband balun with 1:4 impedance transformation ratio using transmission-line transformers. The proposed ultrabroadband balun consists of one 1:1 transmission-line transformer as a balun and two 1:4 transmission-line transformers for impedance transformation. Each transmission-line transformer is based on a coaxial line, which is wound around a ferrite core to extend the bandwidth to the lower frequency region. Experimentally optimized offset transmission lines are used to compensate for the phase imbalance characteristics at the high frequency band. The implemented ultrabroadband balun operates from 300 kHz to 400 MHz with a return loss of below 12 dB and an insertion loss of less than 1 dB. The magnitude and phase imbalance for the balanced signal output are both less than 0.5 dB and 2.0°, respectively. An outstanding relative bandwidth (the ratio of the highest frequency to the lowest frequency in the operational band) of 1330 was achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1974–1978, 2014

Electroactive polymers are smart materials that respond to electrical stimulation by changing their shape and size. The objective of this study is to investigate the applicability of the poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer in sensors or actuators in an in vivo environment. The basic mechanical properties of P(VDF-TrFE) thin films were estimated by carrying out tensile and creep tests using specimens submerged in water at 30°C for a few weeks. Furthermore, X-ray diffraction analysis was employed to observe the micro-structural changes in the P(VDF-TrFE) films due to water absorption wherein water intercalated in the interstitial sites between the chains of the P(VDF-TrFE) films. Consequently, the mechanical properties of the P(VDF-TrFE) films were enhanced due to water absorption. POLYM. ENG. SCI., 54:2654–2659, 2014. © 2013 Society of Plastics Engineers

There is a controversy on the causal relationship of sexual intercourse as a cause of sudden death. Since sildenafil (Viagra™) has been introduced in 1998, there are more concerns on the safety issue of sildenafil and sexual activity as a forensic determination of the cause of death in those cases. We have collected 68 cases of sudden death occurred within 24 hours after sexual intercourse among 13,824 cases for five years from 2001 at the head office of the National Institute of Scientific Investigation in Seoul, Korea. There were 59 men and 9 women (M:F = 6.6:1). The most common cause of death was ischemic heart disease (20 in 68, 29.4%) in both men and women. Sildenafil (Viagra™) was detected in blood in 8 men and only in gastric content in 2 men (10/59, 17.0%). The level in the 8 men was in range of 0.04 to 0.48 with average 0.15 μg/ml. We could not conclude at this study on whether sexual activities and/or sildenafil are considered to have significant contribution to their death, but we would like to warn patients with cardiovascular diseases for the possible risk for sudden unexpected death particularly when their environments are in an unusual situation.

Pneumothorax is a common and serious complications related to acupuncture needling. Although there have been several clinical cases of pneumothorax induced by acupuncture, autopsy reports on cases of sudden death with the typical gross pathological findings are rare. In the two cases presented here, the deceased suffered dyspnea and chest discomfort after the completion of acupuncture treatments and were found dead within a few hours. Acupuncture pathways from the skin to the lungs, resulting in total bilateral lung collapse were found upon autopsy in these cases. When a sudden death occurs in association with acupuncture the possibility of pneumothorax should be considered and there should be meticulous efforts to find evidence during forensic autopsy.

Background and Objectives: Predicting the prognosis in gastric carcinoma patients with intermediate stages is difficult. We investigated the prognostic impacts of CD44 and nm23 expression in a homogeneous group of patients with stage II and IIIA gastric carcinoma who had undergone curative resections. Methods: A total of 261 paraffin-embedded gastric carcinomas were stained with the monoclonal antibodies CD44 and nm23 using the labeled streptovidin biotin method. Results: The expression of CD44 and nm23 was detected, respectively, in 31.0% (81/261) and 70.1% (183/261) of all tumors. There was no correlation between CD44 expression and clinicopathological variables. However, nm23 was more frequently expressed in older patients with differentiated adenocarcinoma. A significant difference in 5-year survival rates was found between patients with CD44-positive (43.2%) and CD44-negative tumors (63.4%), (P = 0.0018). However, there was no significant difference in 5-year survival rates between patients with nm23-positive (54.7%) and nm23-negative tumors (62.7%) (P = 0.2734). Conclusions: CD44 expression was a significant adverse prognostic factor in gastric carcinoma and may be a predictor of metastatic potential of the primary tumor. By contrast, immunohistochemical detection of nm23 expression was not a predictor of outcome of patients with gastric carcinoma.

In this paper, a bandpass filter using stepped-impedance coaxial resonators is presented. Each stepped-impedance resonator (SIR) is composed of ceramic/material to ensure temperature stability of the resonant frequency; one has a positive temperature coefficient of resonant frequency (τf), and the other has a negative τf. A capacitively coupled three-pole bandpass filter is designed and fabricated to have a center frequency of 915 MHz and a passband bandwidth of 20 MHz. The improved temperature stability of this filter is demonstrated by experimental results. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 508–510, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10651