Electromagnetic Interference Shielding Behavior of Magnetic Carbon Fibers Prepared by Electroless FeCoNi-Plating

In this study, soft magnetic metal was coated on carbon fibers (CFs) using an electroless FeCoNi-plating method to enhance the electromagnetic interference (EMI) shielding properties of CFs. Scanning electron microscopy, X-ray diffraction, and a vibrating sample magnetometer were employed to determine the morphologies, structural properties, and magnetic properties of the FeCoNi-CFs, respectively. The EMI shielding behavior of the FeCoNi-CFs was investigated in the frequency range of 300 kHz to 3 GHz through vector network analysis. The EMI shielding properties of the FeCoNi-CFs were significantly enhanced compared with those of the as-received CFs. The highest EMI shielding effectiveness of the 60-FeCoNi-CFs was approximately 69.4 dB at 1.5 GHz. The saturation magnetization and coercivity of the 60-FeCoNi-CFs were approximately 103.2 emu/g and 46.3 Oe, respectively. This indicates that the presence of FeCoNi layers on CFs can lead to good EMI shielding due to the EMI adsorption behavior of the magnetic metal layers.     

Carbonization of Graphene-Doped Isocyanate-Based Polyimide Foams to Achieve Carbon Foams with Excellent Electromagnetic Interference Shielding Performance

Lightweight carbon foams with excellent electromagnetic interference (EMI) shielding performance were prepared by carbonization process, using isocyanate-based polyimide foams as carbon precursors. The influence of carbonization temperature and graphene-doping on the morphological, electrical and EMI shielding effectiveness (SE) of corresponding carbon foams was studied in detail. Results showed that the addition of graphene was beneficial to the improvement of electrical conductivity and EMI shielding performance of carbon foams. The electrical conductivity of carbon foams increased with the carbonization temperature which was related to the increase of graphitization degree. Collapse of foam cells was observed at higher carbonization temperatures, which was detrimental to the overall EMI SE. The optimal carbonization temperature was found at 1100 °C and the carbon foams obtained from 0.5 wt% graphene-doped foams exhibited a specific EMI SE of 2886 dB/(g/cm³), which shows potential applications in fields such as aerospace, aeronautics and electronics.     

A Carbon Composite Film with Three-Dimensional Reticular Structure for Electromagnetic Interference Shielding and Electro-Photo-Thermal Conversion

The design of flexible wearable electronic devices that can shield electromagnetic waves and work in all weather conditions remains a challenge. We present in this work a low-cost technology to prepare an ultra-thin carbon fabric–graphene (CFG) composite film with outstanding electromagnetic interference shielding effectiveness (EMI SE) and electro-photo-thermal effect. The compatibility between flexible carbon fabric skeleton and brittle pure graphene matrix empowers this CFG film with adequate flexibility. The reticular fibers and porous structures play a vital role in multiple scattering and absorption of electromagnetic waves. In the frequency range of 30–1500 MHz, the CFG film can achieve a significantly high EMI SE of about 46 dB at tiny thickness (0.182 mm) and density (1.4 g cm⁻³) predominantly by absorption. At low safe voltages or only in sunlight, the film can self-heat to its saturation value rapidly in 40 s. Once the electricity or light supply is stopped, it can quickly dissipate heat in tens of seconds. A combination of the EMI SE and the prominent electro-photo-thermal effect further enables such a remarkable EMI shielding film to have more potential applications for communication devices in extreme zones.     

Anisotropic PDMS/Alumina/Carbon Fiber Composites with a High Thermal Conductivity and an Electromagnetic Interference Shielding Performance

The development of polymer-based composites with a high thermal conductivity and electromagnetic interference (EMI) shielding performance is crucial to the application of polymer-based composites in electronic equipment. Herein, a novel strategy combining ice-templated assembly and stress-induced orientation was proposed to prepare polydimethylsiloxane (PDMS)/alumina/carbon fiber (CF) composites. CF in the composites exhibited a highly oriented structure in the horizontal direction. Alumina was connected to the CF, promoting the formation of thermal conductive pathways in both the horizontal and vertical directions. As the CF content was 27.5 vol% and the alumina content was 14.0 vol%, the PDMS/alumina/CF composite had high thermal conductivities in the horizontal and vertical directions, which were 8.44 and 2.34 W/(m·K), respectively. The thermal conductivity in the horizontal direction was 40.2 times higher than that of PDMS and 5.0 times higher than that of the composite with a randomly distributed filler. The significant enhancement of the thermal conductivity was attributed to the oriented structure of the CF and the bridging effect of alumina. The PDMS/alumina/CF composite exhibited an excellent EMI shielding effectiveness of 40.8 dB which was 2.4 times higher than that of the composite with a randomly distributed filler. The PDMS/alumina/CF composite also exhibited a low reflectivity of the electromagnetic waves. This work could provide a guide for the research of polymer-based composites with a high thermal conductivity and an EMI shielding performance.     

Observer Variability in ECG Interpretation for Thrombolysis Eligibility: Experience and Context Matter

BACKGROUND: Despite the known benefit of thrombolysis it remains underutilized among eligible patients with acute myocardial infarction. We sought to determine whether potential errors in ECG interpretation might be a contributing factor and to what extent clinical history, a checklist outlining recognized inclusion criteria and a computerized interpretation would influence reliability and accuracy. METHODS: Seventy-five ECGs were interpreted on 8 separate occasions by 9 clinicians (3 cardiologists, 3 cardiology fellows, 3 medical residents) according to a 2 x 2 x 2 factorial design. RESULTS: The overall level of agreement among all raters was substantial with a kappa (kappa) of 70.4%. Intra-observer ECG reading reliability was stronger among cardiologists (CC) as compared with cardiology fellows (CF) and medical residents (MR). Similarly, inter-observer reliability was substantial to very good and a gradient was seen with greater reliability among CC, followed by CF, then MR ( P = 0.0013). CC recommended thrombolysis significantly more frequently ( p < 0.001) than either CF or MR. Trainees were biased by the presence of a computerized ECG interpretation resulting in a decision to recommend thrombolysis administration less often. CONCLUSION: The reliability of ECG interpretation for deciding to administer thrombolysis was substantial; there was a gradient from lowest to highest commensurate with training and experience. Errors in thrombolysis eligibility are influenced by clinical history and the presence of a computerized ECG interpretation among less experienced clinicians.     

Automated serial ECG comparison improves computerized interpretation of 12-lead ECG

Background

Interpretation of a patient's 12-lead ECG frequently involves comparison to a previously recorded ECG. Automated serial ECG comparison can be helpful not only to note significant ECG changes but also to improve the single-ECG interpretation. Corrections from the previous ECG are carried forward by the serial comparison algorithm when measurements do not change significantly.

Methods

A sample of patients from three hospitals was collected with two or more 12-lead ECGs from each patient. There were 233 serial comparisons from 143 patients. 41% of patients had two ECGs and 59% of patients had more than two ECGs. ECGs were taken from a difficult population as measured by ECG abnormalities, 197/233 abnormal, 11/233 borderline, 14/233 otherwise-normal and 11/233 normal. ECGs were processed with the Philips DXL algorithm and then in time order for each patient with the Philips serial comparison algorithm. To measure accuracy of interpretation and serial change, an expert cardiologist corrected the ECGs in stages. The first ECG was corrected and used as the reference for the second ECG. The second ECG was then corrected and used as the reference for the third ECG and so on. At each stage, the serial comparison algorithm compared an unedited ECG to an earlier edited ECG. Interpretation accuracy was measured by comparing the algorithm to the cardiologist on a statement by statement basis. The effect of serial comparison was measured by the sum of interpretive statement mismatches between the algorithm and cardiologist. Statement mismatches were measured in two ways, (1) exact match and (2) match within the same diagnostic category.

Results

The cardiologist used 910 statements over 233 ECGs for an average number of 3.9 statements per ECG and a mode of 4 statements. When automated serial comparison was used, the total number of exact statement mismatches decreased by 29% and the total same-category statement mismatches decreased by 47%.

Conclusion

Automated serial comparison improves interpretation accuracy in addition to its main role of noting differences between ECGs.     

Interference by Cellular Telephone with an Implantable Loop Recorder

We report the observation of interference between an implanted loop recorder and a cellular telephone when the latter was placed over the subcutaneous pocket. The artifact produced during the ringing of the telephone was automatically recorded and stored in the device memory. A similar interference was documented during ex vivo testing.     

Evaluation of Hematocrit Interference With MyStar Extra and Seven Competitive Devices

Background:

In previous studies, meters employing dynamic electrochemistry (DE), have been shown to correct for hematocrit (HCT) interference. This laboratory investigation assessed the HCT stability of MyStar Extra (Sanofi) in comparison to 7 competitive devices (Accu-Chek Aviva Nano & Accu-Chek Performa, Roche Diagnostics; Contour XT and Contour Link, Bayer; FreeStyle Freedom Lite, Abbott; MyLife Pura, Ypsomed; OneTouch Verio Pro, LifeScan).

Method:

Venous heparinized blood was freshly drawn, immediately aliquoted, and manipulated to contain 3 different blood glucose concentrations (50-80 mg/dL, 150-180 mg/dL, and 350-400 mg/dL) and 5 different HCT levels (20-25%, 30-35%, 40-45%, 50-55%, and 60-65%). After careful oxygenation to normal blood oxygen pressure, each of the 15 different samples was measured 8 times with 2 devices and 2 strip lots of each meter (32 measurements/meter/sample). YSI Stat 2300 served as laboratory reference method. Next to determination of the mean absolute relative deviation (MARD), stability to HCT influence was assumed, when less than 10% difference occurred between the highest and lowest mean glucose deviations in relation to HCT over all tested glucose ranges (HIF: hematocrit interference factor).

Results:

Four of the devices showed stable performance: Contour XT (MARD: 1.3%/HIF: 6.1%), MyStar Extra (4.7%/7.1%), OneTouch Verio Pro (4.5%/7.3%), and Contour Link (6.3%/9.3%). The 4 other meters were influenced by HCT (Accu-Chek Performa: 4.7%/20.9%, Accu-Chek Aviva Nano: 4.5%/22.4%, FreeStyle Freedom Lite: 4.8%/24.5%; MyLife Pura: 6.4%/28.7%).

Conclusions:

In this study, all meters showed a good accuracy, but only 50% of them, including MyStar Extra, were shown to reliably correct for potential hematocrit influence on the meter results.     

The Evolution of Ambulatory ECG Monitoring

Ambulatory Holter electrocardiographic (ECG) monitoring has undergone continuous technological evolution since its invention and development in the 1950s era. With commercial introduction in 1963, there has been an evolution of Holter recorders from 1 channel to 12 channel recorders with increasingly smaller storage media, and there has evolved Holter analysis systems employing increasingly technologically advanced electronics providing a myriad of data displays. This evolution of smaller physical instruments with increasing technological capacity has characterized the development of electronics over the past 50 years. Currently the technology has been focused upon the conventional continuous 24 to 48 hour ambulatory ECG examination, and conventional extended ambulatory monitoring strategies for infrequent to rare arrhythmic events. However, the emergence of the Internet, Wi-Fi, cellular networks, and broad-band transmission has positioned these modalities at the doorway of the digital world. This has led to an adoption of more cost-effective strategies to these conventional methods of performing the examination. As a result, the emergence of the mobile smartphone coupled with this digital capacity is leading to the recent development of Holter smartphone applications. The potential of point-of-care applications utilizing the Holter smartphone and a vast array of new non-invasive sensors is evident in the not too distant future. The Holter smartphone is anticipated to contribute significantly in the future to the field of global health.     

Effect of ECG filter settings on J-waves

Background

While J-waves were observed in healthy populations, variations in their reported incidence may be partly explicable by the ECG filter setting.

Methods

We obtained resting 12-lead ECG recordings in 665 consecutive patients and enrolled 112 (56 men, 56 women, mean age 59.3 ± 16.1 years) who manifested J-waves on ECGs acquired with a 150-Hz low-pass filter. We then studied the J-waves on individual ECGs to look for morphological changes when 25-, 35-, 75-, 100-, and 150 Hz filters were used.

Results

The notching observed with the 150-Hz filter changed to slurring (42%) or was eliminated (28%) with the 25-Hz filter. Similarly, the slurring seen with the 150-Hz filter was eliminated on 71% of ECGs recorded with the 25-Hz filter. The amplitude of J-waves was significantly lower with 25- and 35-Hz than 75-, 100-, and 150-Hz filters (p < 0.0001).

Conclusions

The ECG filter setting significantly affects the J-wave morphology.     

Inappropriate Shock Delivery Due to Interference between a Washing Machine and an Implantable Cardioverter Defibrillator

Electromagnetic interference with implantable cardioverter defibrillators (ICD) can cause inappropriate delivery of therapies or temporary inhibition of ICD functions. The presented case describes electromagnetic interference between a washing machine and an ICD resulting in an inappropriate discharge of the device due to false detection of ventricular fibrillation.     

Analysis of Electromagnetic Shielding Properties of a Material Developed Based on Silver-Coated Copper Core-Shell Spraying

This study proposes an electromagnetic shielding material sprayed with silver-coated copper powder (core-shell powder). The shielding properties of the material are analyzed in details section. Cross-sectional observation and sheet resistance measurement were used to determine the thickness and electrical conductivity of the electromagnetic shielding layer, which was generated by spray-coating; this aided in confirming the uniformity of the coating film. The results indicate that the electromagnetic interference shielding effectiveness increases when the silver-coated copper paste (core-shell paste) is used as the coating material rather than the conventional aluminum base. The proposed material can be used in various frequency ranges owing to the excellent shielding effectiveness of the core-shell paste used in this study. Further investigations on the optimized spray-coating type of electromagnetic shielding material are required based on the composition of the core-shell paste and the thickness of the coating film.     

社区医院应用网络化心电系统的临床意义

目的：探讨社区医院应用网络化心电系统的临床意义。方法社区医院基层心电医生筛选需要会诊的心电图或疑难心电图,利用网络化心电系统将心电信息上传到我院心电网络会诊中心。我院心电会诊中心的专职医师对心电图图谱进行会诊,会诊结果反馈回社区医院。结果本研究共收集到心电图378份,共发现异常心电图213例,可能发生恶性事件的心电图29例。经分析发现漏诊184例（48．68％）、误诊45例（11．90％）。结论网络化心电系统的应用使社区医院能够及时发现危重心电图,纠正漏诊和误诊,减少恶性心脏事件的发生;同时,解决了基层心电医生诊断力量薄弱的问题,完善了社区医院的医疗服务功能,取得了良好成效。     

Synergistic Strengthening of Mechanical Properties and Electromagnetic Interference Shielding Performance of Carbon Nanotubes (CNTs) Reinforced Magnesium Matrix Composites by CNTs Induced Laminated Structure

In this study, we reported a laminated CNTs/Mg composite fabricated by spray-deposition and subsequent hot-press sintering, which realized simultaneous enhancement effects on strength and electromagnetic interference (EMI) shielding effectiveness (SE) by the introduced CNTs and CNT induced laminated ‘Mg-CNT-Mg’ structure. It was found that the CNTs/Mg composite with 0.5 wt.% CNTs not only exhibited excellent strength-toughness combination but also achieved a high EMI SE of 58 dB. The CNTs increased the strength of the composites mainly by the thermal expansion mismatch strengthening and blocking dislocation movements. As for toughness enhancement, CNTs induced laminated structure redistributes the local strain effectively and alleviates the strain localization during the deformation process. Moreover, it could also hinder the crack propagation and cause crack deflection, which resulted in an increment of the required energy for the failure of CNTs/Mg composites. Surprisingly, because of the laminated structure induced by introducing CNTs, the composite also exhibited an outperforming EMI SE in the X band (8.2–12.4 GHz). The strong interactions between the laminated ‘Mg-CNT-Mg’ structure and the incident electromagnetic waves are responsible for the increased absorption of the electromagnetic radiation. The lightweight CNTs/Mg composite with outstanding mechanical properties and simultaneously increased EMI performance could be employed as shell materials for electronic packaging components or electromagnetic absorbers.     

多床位心电遥测监护系统的研制

目的　本文主要介绍作者研制的心电遥测监护系统及在研制过程中所考虑的问题。方法　本遥测系统采用个人计算机和心电遥测盒 ,将采集的心电信号以无线的方式进行实时传输。具有波形与数值集中显示、存储、回放、打印、数据管理的功能。结果　作者设计完成了四床位的遥测监护系统并已经广泛应用于临床 ,也得到了临床的认可。结论　采用计算机设计的遥测系统 ,在功能和性能上比进口专用型的设计有着操作方便、升级容易和显示更清晰的优势 ,对心电的回放 ,心电的筛查、异常心电的分析和统计都可以方便的实现。     

精准新心电图对冠心病诊断价值的初步探讨

目的探讨精准新心电图(原尼沙赫电图saah ECG)在冠心病诊断中的临床应用价值。方法应用美国菲士公司生产的PHS-A10检测仪机,分别对81例冠心病患者(冠状动脉造影显示至少一支主要冠脉分支狭窄≥50%)和19例非冠心病患者(冠脉造影显示狭窄程度50%)进行同步精准新心电图及心电图检查;对精准新心电图的两个参数(ST-T段的小波个数及小波在所占时程比例)及心电图(ECG)进行分析。结果精准新心电图、ECG诊断冠心病的敏感性分别为97.5%、69.1%,特异性分别为31.6%、57.9%。结论精准新心电图是一项记录心脏电活动的新技术,对于冠心病的诊断价值其敏感性优于心电图。     

Methods for Improving the Diagnosis of a Brugada ECG Pattern

Brugada syndrome (BrS) is an inherited channelopathy that predisposes individuals to malignant arrhythmias and can lead to sudden cardiac death. The condition is characterized by two electrocardiography (ECG) patterns: the type‐1 or “coved” ECG and the type‐2 or “saddleback” ECG. Although the type‐1 Brugada ECG pattern is diagnostic for the condition, the type‐2 Brugada ECG pattern requires differential diagnosis from conditions that produce a similar morphology. In this article, we present a case that is suspicious but not diagnostic for BrS and discuss the application of ECG methodologies for increasing or decreasing suspicion for a diagnosis of BrS.     

Ubiquitous Wireless ECG Recording: A Powerful Tool Physicians Should Embrace

Ubiquitous Wireless ECG Recording . The use of smart phones has increased dramatically and there are nearly a billion users on 3G and 4G networks worldwide. Nearly 60% of the U.S. population uses smart phones to access the internet, and smart phone sales now surpass those of desktop and laptop computers. The speed of wireless communication technology on 3G and 4G networks and the widespread adoption and use of iOS equipped smart phones (Apple Inc., Cupertino, CA, USA) provide infrastructure for the transmission of wireless biomedical data, including ECG data. These technologies provide an unprecedented opportunity for physicians to continually access data that can be used to detect issues before symptoms occur or to have definitive data when symptoms are present. The technology also greatly empowers and enables the possibility for unprecedented patient participation in their own medical education and health status as well as that of their social network. As patient advocates, physicians and particularly cardiac electrophysiologists should embrace the future and promise of wireless ECG recording, a technology solution that can truly scale across the global population. (J Cardiovasc Electrophysiol, Vol. 24, pp. 480‐483, April 2013)     

心电远程监护系统的研制

本系统采用由患者佩带的袖珍式心电监护盒,对其心电进行监护和初步分析,记录和存储异常心电并报警,在需要时将已存储的或实时的心电信号通过公用电话网以数字化方式传送至医院监护中心,供回放和分析处理,使医生能及时地诊断和提供救治指导,并可对所有信息建档和打印.