Wireless non-invasive continuous respiratory monitoring with FMCW radar: a clinical validation study

Altered respiratory rate is one of the first symptoms of medical conditions that require timely intervention, e.g., sepsis or opioid-induced respiratory depression. To facilitate continuous respiratory rate monitoring on general hospital wards a contactless, non-invasive, prototype monitor was developed using frequency modulated continuous wave radar. We aimed to study whether radar can reliably measure respiratory rate in postoperative patients. In a diagnostic cross-sectional study patients were monitored with the radar and the reference monitor (pneumotachograph during mechanical ventilation and capnography during spontaneous breathing). Eight patients were included; yielding 796 min of observation time during mechanical ventilation and 521 min during spontaneous breathing. After elimination of movement artifacts the bias and 95 % limits of agreement for mechanical ventilation and spontaneous breathing were ?0.12 (?1.76 to 1.51) and ?0.59 (?5.82 to 4.63) breaths per minute respectively. The radar was able to accurately measure respiratory rate in mechanically ventilated patients, but the accuracy decreased during spontaneous breathing.     

Preferred sensor sites for surface EMG signal decomposition

Technologies for decomposing the electromyographic (EMG) signal into its constituent motor unit action potential trains have become more practical by the advent of a non-invasive methodology using surface EMG (sEMG) sensors placed on the skin above the muscle of interest (De Luca et al 2006 J. Neurophysiol. 96 1646-57 and Nawab et al 2010 Clin. Neurophysiol. 121 1602-15). This advancement has widespread appeal among researchers and clinicians because of the ease of use, reduced risk of infection, and the greater number of motor unit action potential trains obtained compared to needle sensor techniques. In this study we investigated the influence of the sensor site on the number of identified motor unit action potential trains in six lower limb muscles and one upper limb muscle with the intent of locating preferred sensor sites that provided the greatest number of decomposed motor unit action potential trains, or motor unit yield. Sensor sites rendered varying motor unit yields throughout the surface of a muscle. The preferred sites were located between the center and the tendinous areas of the muscle. The motor unit yield was positively correlated with the signal-to-noise ratio of the detected sEMG. The signal-to-noise ratio was inversely related to the thickness of the tissue between the sensor and the muscle fibers. A signal-to-noise ratio of 3 was found to be the minimum required to obtain a reliable motor unit yield.     

采集表面肌电信号应用于动作识别的可行性

背景:文献表明上肢前臂运动时所产生的表面肌电信号具有非线性特征,而肢体运动时肌电信号又呈现出非平稳特性.目的:设计一种简单的拾取电路采集表面肌电信号,拟应用于动作肌电信号的特征识别.方法:根据表面肌电信号的特点,设计高共模抑制比的前端放大电路,抑制共模干扰;采用低通滤波电路,有源双T带阻滤波器对信号进行去噪处理;对采集得到的信号进行小波包变换,得到信号的特征量.结果与结论:所设计的表面肌电信号检测电路具有较高共模抑制比,并能有效地滤除50 Hz工频信号,可以满足肌电信号采集电路的基本要求.肌电信号的处理结果表明采用子频段能量值的方法可以区分手部4种不同动作.     

采集表面肌电信号应用于动作识别的可行性

背景：文献表明上肢前臂运动时所产生的表面肌电信号具有非线性特征,而肢体运动时肌电信号又呈现出非平稳特性。目的：设计一种简单的拾取电路采集表面肌电信号,拟应用于动作肌电信号的特征识别。方法：根据表面肌电信号的特点,设计高共模抑制比的前端放大电路,抑制共模干扰;采用低通滤波电路,有源双T带阻滤波器对信号进行去噪处理;对采集得到的信号进行小波包变换,得到信号的特征量。结果与结论：所设计的表面肌电信号检测电路具有较高共模抑制比,并能有效地滤除50Hz工频信号,可以满足肌电信号采集电路的基本要求。肌电信号的处理结果表明采用子频段能量值的方法可以区分手部4种不同动作。     

介绍一种战备用便携式输液架

在战备和院前急救输液过程中，输液瓶往往需要护士手持，或者在行进中应用常规输液架挂瓶，路途颠簸，输液瓶极易脱落而影响治疗，且携带不方便。针对上述常规输液架在特殊场合中应用的不足，特自行设计一种便携式输液架，用于平时或战时，院前抢救，家庭输液，野战训练，效果理想。现介绍如下。     

介绍一种战备用便携式输液架

在战备和院前急救输液过程中,输液瓶往往需要护士手持,或者在行进中应用常规输液架挂瓶,路途颠簸,输液瓶极易脱落而影响治疗,且携带不方便.针对上述常规输液架在特殊场合中应用的不足,特自行设计一种便携式输液架,用于平时或战时,院前抢救,家庭输液,野战训练,效果理想.现介绍如下.……     

Use of a ramp surface for lower extremity exercise with burn-injured patients

The use of a ramp surface in our Burn Center has demonstrated benefits in improving gait, standing postures, and lower extremity muscle length. This technique has been effective with a wide age range of patients and is most useful as part of an overall treatment program including prestretching of lower extremities.     

Potential of surface acoustic wave biosensors for early sepsis diagnosis

Early diagnosis of sepsis is a difficult problem for intensivists and new biomarkers for early diagnosis have been difficult to come by. Here we discuss the potential of adapting a technology from the electronics industry, surface acoustic wave (SAW) sensors, for diagnosis of multiple markers of sepsis in real time, using non-invasive assays of exhaled breath condensate. The principles and advantages of the SAW technology are reviewed as well as a proposed plan for adapting this flexible technology to early sepsis detection.     

Thermally enhanced signal strength and SNR improvement of photoacoustic radar module

A thermally enhanced method for improving photoacoustic imaging depth and signal-to-noise (SNR) ratio is presented in this paper. Experimental results showed that the maximum imaging depth increased by 20% through raising the temperature of absorbing biotissues (ex-vivo beef muscle) uniformly from 37 to 43°C, and the SNR was increased by 8%. The parameters making up the Gruneisen constant were investigated experimentally and theoretically. The studies showed that the Gruneisen constant of biotissues increases with temperature, and the results were found to be consistent with the photoacousitc radar theory.OCIS codes: (170.5120) Photoacoustic imaging, (170.3880) Medical and biological imaging     

Use of high-frequency jet ventilation to prevent aspiration in a patient with an uncuffed tracheostomy tube

We report the use of high-frequency jet ventilation (HFJV) in a patient with an uncuffed tracheostomy tube who had significant pulmonary aspiration of upper-airway secretions. Respiratory secretions decreased during HFJV, indicating that the patient was no longer aspirating. Despite a continuous flow of gas out of the patient's nose and mouth, arterial blood gases remained within acceptable limits. We conclude that HFJV can prevent aspiration and maintain adequate ventilation when used with an uncuffed tracheostomy tube.     

Slowness curve surface acoustic wave transducers for optimized acoustic streaming

Surface acoustic waves can induce force gradients on the length scales of micro- and nanoparticles, allowing precise manipulation for particle capture, alignment and sorting activities. These waves typically occupy a spatial region much larger than a single particle, resulting in batch manipulation. Circular arc transducers can focus a SAW into a narrow beam on the order of the particle diameter for highly localised, single-particle manipulation by exciting wavelets which propagate to a common focal point. The anisotropic nature of SAW substrates, however, elongates and shifts the focal region. Acousto-microfluidic applications are highly dependent on the morphology of the underlying substrate displacement and, thus, become dependent on the microchannel position relative to the circular arc transducer. This requires either direct measurement or computational modelling of the SAW displacement field. We show that the directly measured elongation and shift in the focal region are recapitulated by an analytical model of beam steering, derived from a simulated slowness curve for 128° Y-cut lithium niobate. We show how the negative effects of beam steering can be negated by adjusting the curvature of arced transducers according to the slowness curve of the substrate, for which we present a simple function for convenient implementation in computational design software. Slowness-curve adjusted transducers do not require direct measurement of the SAW displacement field for microchannel placement and can capture smaller particles within the streaming vortices than can circular arc IDTs.

Adjusting focused IDT curvature according to the substrate slowness curve permits better focusing for enhanced acoustofluidic microparticle capture.     

Identification of a novel signal transduction surface molecule on human cytotoxic lymphocytes

In this study, we have used a newly generated monoclonal antibody (mAb C1.7) to identify a novel 38-kD signal-transducing surface molecule (p38) expressed by lymphocyte subsets capable of cell-mediated cytotoxicity. Virtually all CD16+/CD56+ natural killer (NK) cells and approximately half of CD8+ (T cell receptor [TCR] alpha/beta+) T cells and TCR-gamma/delta+ T cells express the p38 surface molecule. Stimulation of p38 on NK cells with mAb C1.7 activated cytotoxicity, induced lymphokine production, and initiated polyphosphoinositol turnover and [Ca2+]i increases. Unlike other NK cell surface molecules that activate cytotoxicity, p38 stimulation did not result in the release of the granule enzyme N-carbobenzoxy-L-thiobenzyl ester- esterase even under conditions in which mAb C1.7 induced NK cell- mediated redirected lysis of Fc gamma R+ target cells. Activated (recombinant interleukin 2 [rIL-2], 5 d) CD8+ T cells mediated non- major histocompatibility complex (MHC)-restricted cytotoxicity, and the CD8+/p38+ subset contained the overwhelming majority of this activity. F(ab')2 fragments of mAb C1.7 inhibited non-MHC-restricted cytotoxicity mediated by resting NK cells and rIL-2-cultured T cells but did not affect spontaneous cytotoxicity mediated by activated, cultured NK cells. Taken as a whole, our results suggest that p38 may have a direct role in the recognition, signal transduction, and/or lytic mechanisms of non-MHC-restricted cytotoxicity.     

便携式导管消毒冲洗器的研制与应用

介入导管的消毒,一般是将导管浸泡在2 %戊二醛消毒液中,用针管向导管腔内注入消毒液,这种消毒方法对较长的导管内腔达不到彻底的消毒效果,一是针管推入压力不够,导管腔内消毒液灌注不满,管腔内消毒不完全;二是消毒后,导管腔内消毒液冲洗不彻底,残留在导管腔内的消毒液对人体器官组织造成伤害。为解决上述问题,我们研制了“便携式导管消毒冲洗器”,并取得国家知识产权局实用新型专利。1　便携式导管消毒冲洗器构造(见图1)　　箱体的底部位置固定有一个与箱体内腔相通的排污阀,箱体顶盖上分别安装有手柄、微型电泵、加液口,手柄上安装有微型电…     

A model of the received signal for shipborne inverse synthetic aperture radar together with an error analysis

In shipborne inverse synthetic aperture radar (ISAR), not only the target, but also the radar ship will have nonstationary 3-dimensional rotations induced by the irregular sea wave. Thus, how to compensate the radar ship’s rotations is the key problem in reconstructing the shipborne ISAR image of ship target successfully. In this letter, a novel received signal model of shipborne ISAR is proposed. On the basis of the proposed model, the Doppler frequency induced by the rotations of the target and the radar ship can be separated from the received signal, individually. An analysis of the effects of the radar ship’s rotations on the obtained image is given. Error analysis and imaging simulation are done and the results verified the correctness of the proposed model and the effects of the radar ship’s rotations.