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Portable ultrasound has been extensively used for diagnostic applications in health monitoring, emergency rooms, and ambulances. However, these handheld ultrasound systems may suffer from heat and battery issues attributed to the large power consumption of the transmitter. Additionally, the largest portion of the direct current (DC) power consumption can be attributed to the amplifier in the digital-to-analog converter (DAC) of the transmitter and to the analog-to-digital converter (ADC) of the receiver. Therefore, the number of transmit/receive channels in a portable ultrasound instrument is one of the crucial design factors regarding heat and battery related issues. To address these problems, we propose an acoustic-field beamforming (AFB) technique for low-power portable ultrasound systems with a single receive and five transmit channels. Finally, the simulation, experimental, and in vivo results verified the feasibility of this approach.

Portable ultrasound devices with less numbers of transducers become popularly spread soon or later. Accordingly, this work explores how to make quality of ultrasonic B-mode images from 32 channels approaching to that from 128 channels by using Deep Neural Networks (DNNs). Based on the concepts of auto-encoder, context encoder, semi-supervised latent-class learning, and context-conditional Generative Adversarial Network (GAN), we develop the Context Encoder Reconstruction GAN (CER-GAN)., which adopts the contour learning mechanism to establish the relationship between 32-channel and 128-channel Point Spread Functions (PSF) via the mini-batch training. In our experiments, 20 pairs of 32 and 128-channel ultrasound images were used where the way of “leave one person out” was employed for cross-validation. Our CER-GAN automatically encodes 32-channel PSF blocks, and generates pseudo 128-channel PSF ones which are matched with real 128-channel ones to obtain discrimination and amendment from the adversarial mechanism. Finally, these pseudo blocks are used to yield an improved image. The experimental results reveal that the proposed CER-GAN outperforms the conventional DNNs. In Full Width at Half Maximum (FWHM), the minimum distinguishable pixel lengths from the 32-channel, CER-GAN, and 128-channel images are 13.34, 11.15, and 8.62, respectively. In Contrast Noise Ratio (CNR)/PICMUS CNR, the scores of the 32-channel, CER-GAN, and 128-channel images are 0.939/2.381, 1.508/6.502, and 1.422/6.002, respectively. The reason of the favorable scores from CER-GAN is that the background speckle noise is lowered to some extent. Therefore, our CER-GAN can effectively ameliorate the quality of 32-channel ultrasound imaging, close to that of 128-channel one.

With some ballistic missile erecting system as subject, a virtual prototype is constructed, for virtual measuring of the load spectrum of the erecting system. By FEM analysis and damage analysis, the dangerous position of is uncovered, and the stress-time history is obtained. By use of material fatigue feature curve in combination with the stress-time history, the fatigue life of system components is studied.

Purpose The microcirculatory system of the human body is closely related to its physiological conditions. The laser Doppler flowmeter can detect symptoms through variations in the microcirculation; however, the present commercial Doppler flowmeter is very expensive, heavy, and inconvenient to carry. Therefore, an inexpensive, small, and portable laser Doppler flowmeter is proposed.

The new application of ultrasonic imaging to transient elastography has triggered the emergence of high frame-rate imaging. Using plane wave excitation (PWE), a single insonification is sufficient to form an image; thus PWE is one of the methods for achieving high frame-rate imaging. However, due to the lack of transmit focusing, the signal-to-noise-ratio (SNR), contrast, and spatial resolution of the resultant images are lower compared with those using conventional focused transmission. To solve this problem, we propose a filter-based retrospective transmit focusing technique combined with weighting based post filtering - filter-derived coherence-index weighting (FRF+FCI weighting) for plane wave imaging. A 2-D filter is designed and applied to beamformed baseband data to retrieve transmit focusing. Then a filter-derived coherence index (FCI) at each imaging point is used as a weighting factor to further improve the filter-retrieved focusing quality. Here FCI is a coherence measure of the filter-coefficient-weighted baseband data in the sliding filter kernel. Due to the sidelobe-suppression nature of the designed 2-D filter, FCIs are low at sidelobes; thus FCI weighting can further suppress the sidelobe contribution in the filtered baseband data. It is demonstrated that our proposed FRF+FCI weighting technique can improve plane wave imaging quality - reducing the sidelobes, and improving the SNR and spatial resolution while being capable of retaining the high frame rate. In addition, the proposed method is inherently less susceptible to motion artifacts (because being applied over ultrafast plane wave imaging) and phase aberration (because the overall wavefront of the transmit plane wave mitigates the phase aberration on transmit).

Laparoscopy is widely used during living kidney donation, nephrectomy, bariatric surgery, and surgery for gastrointestinal tumors and colorectal cancer. However, laparoscopic surgery requires prolonged use of instruments and has low mechanical efficiency. In addition, to meet specific surgical demands while visualizing the surgical area on the screen, surgical personnel frequently violate the postures proposed by human factor engineering; this naturally results in a physical burden on the personnel. In this study, using laparoscopic nephrectomy as an example, an auxiliary hoisting device for surgery was designed, and pedals from a variety of equipment were integrated into the auxiliary plant. Both entity testing conducted in the hospital and 3D surgical simulation of the auxiliary plant showed that this device could improve compliance with human factor engineering recommendations during laparoscopic surgery and could also promote interaction and tacit understanding between surgical personnel, thereby providing ergonomically optimum conditions during laparoscopy.

The frequencies and vibration modes of a launch platform are acquired through finite element simulation, and their actual values are obtained through modal test. On this basis, constructing objective function for the structure modal parameter relative residual error to be minimum, can transform model updating problem into optimization problem. Then the trust region algorithm is adopted to solve this optimization problem. This algorithm bears better robustness and computing efficiency. Through model updating, the frequency and vibration mode errors are reduced, supplying a basis for further simulation.

High frame rate ultrasound imaging systems can implement innovative applications of real-time 3D ultrasound, elastography, and so on. The approach for reaching high frame rate consists of transmitting single plane wave because emission of a single plane wave is enough to form an image. However, due to the lack of transmit focus, the SNR, and contrast are lower than those with line-by-line scanning. Thus, coherent plane wave compounding (CPWC), which can upgrade the imaging quality, has drawn more and more attention recently. Here, we are interested in the effect of phase aberration, caused by inhomogeneity of sound speed, on CPWC imaging. Degradation between image quality with and without phase aberration is estimated and compared with that using line-by-line scanning and single plane wave imaging (PWI), respectively. Near-field phase screen model was used. The correlation length of the simulated phase-aberration profile was 5 mm, and the maximum phase error varied depending on specific simulation conditions. Images of a 3-mm anechoic cyst at 30-mm depth were simulated using Field II. Four beamforming schemes were considered - line-by-line scanning with transmit focusing at the 30-mm depth and dynamic receive focusing (i.e., ideal focusing), PWI, CPWC using 15 angles with 1-degree separation, and CPWC using 31 angles with 1-degree separation. It is found that the effect of phase aberration on PWI is minimum among the four beamforming schemes. The overall wavefront of the transmit plane wave mitigates the phase aberration on transmit. With phase aberration, as the angles of CPWC increase, the degradation in image quality becomes greater, which is similar to the case with ideal focusing, though the image quality can be upgraded by CPWC with more steered angles.

The laser Doppler flowmeter has become an effective tool for the clinical study of microcirculation with non-invasive measurements and excellent velocity resolution. Microcirculation flow measurements cannot be used as reference criteria for circulation function. Thus, the relative change in fingertip microcirculation was measured through inflation and deflation of an automatic sphygmomanometer wrapped around the arm, and the blood pressure and functional parameters of circulation, such as biological zero (BZ), peak flow (PF) and time to peak flow (tp), were determined. For 50 healthy participants, the correlation coefficients for the laser Doppler flowmeter and oscillometric results were 0.950 and 0.838 for systolic and diastolic pressure, respectively. The mean and standard errors for both methods fell within the range specified in the Association for the Advancement of Medical Instrumentation standards. The BZ of an edema patient was about 5 times higher than normal. For patients with peripheral arterial occlusive disease (PAOD), the PF could not be determined, and the tp was about twice the normal value. The accuracy of blood pressure measurements using the laser Doppler flowmeter was comparable to that of the commonly used oscillometric sphygmomanometer, and the physiological circulation functional parameters were useful in identifying signs of edema and PAOD.

The need of high frame-rate imaging has been triggered by the new applications of ultrasound imaging to transient elastography and real-time 3D ultrasound. Using plane wave excitation (PWE) is one of the methods to achieve very high frame-rate imaging since an image can be formed with a single insonification. However, due to the lack of transmit focusing, the image quality with PWE is lower compared with those using conventional focused transmission. To solve this problem, we propose a filter-retrieved transmit focusing (FRF) technique combined with cross-correlation weighting (FRF+CC weighting) for high frame-rate imaging with PWE. A restrospective focusing filter is designed to simultaneously minimize the predefined sidelobe energy associated with single PWE and the filter energy related to the signal-to-noise-ratio (SNR). This filter attempts to maintain the mainlobe signals and to reduce the sidelobe ones, which gives similar mainlobe signals and different sidelobes between the original PWE and the FRF baseband data. Normalized cross-correlation coefficient at zero lag is calculated to quantify the degree of similarity at each imaging point and used as a weighting matrix to the FRF baseband data to further suppress sidelobes, thus improving the filter-retrieved focusing quality., {"references":["B. Delannoy, R. Torgue, C. Bruneel, and E. Bridou, \"Ultrafast electronical image reconstruction device\" in Echocardiology, vol. 1, C. T.\nLancee, Ed. (The Hague: Nijhoff, 1979), ch. 3, pp. 447-450.","B. Delannoy, R. Torgue, C. Bruneel, E. Bridoux, J. M. Rouvaen, and H.\nLaSota, \"Acoustical image reconstruction in parallel-processing analog\nelectronic systems,\" J. Appl. Phys., vol. 50, pp. 3153-3159, May 1979.","Shattuck, D., Weinshenker, M., Smith, S., and Ramm, O.V.,\n\"Explososcan: a parallel processing technique for high speed ultrasound\nimaging with linear phased arrays,\" J. Acoust. Soc. Am., vol. 75, no. 4, pp. 1273-1282, 1984.","Tanter, M., Bercoff, J., Sandrin, L., and Fink, M., \"Ultrafast Compound\nImaging for 2-D Motion Vector Estimation: Application to Transient Elastography,\" IEEE transactions on ultrasonics, ferroelectrics, and\nfrequency control, vol. 4 , no. 10, pp. 1363-1374, 2002.","Jesper Udesen, F.G., Kristoffer Lindskov Hansen, Jorgen Arendt Jensen,\nCarsten Thomsen, and Michael Bachmann Nielsen, \"High Frame-Rate\nBlood Vector Velocity Imaging Using Plane Waves: Simulations and\nPreliminary Experiments,\" IEEE transactios on ultrasonics, ferroelectrics,\nand frequency control, vol. 55, no. 8, pp. 1729-1743, 2008.","Montaldo, G., Tanter, M., Bercoff, J., Benech, n., and Fink, M.,\n\"Coherent Plane-Wave Compounding for Very High Frame Rate\nUltrasonography and Transient Elastography,\" IEEE transactions on\nultrasonics, ferroelectrics, and frequency control, vol. 56, no. 3, pp.\n489-506, 2009.","Chang-Lin. Hu, Geng-Shi. Jeng, Yu-Hsin. Wang, Pai-Chi. Li, and\nMeng-Lin. Li, Improved Plane-Wave High Frame Rate Imaging Using\nRetrospective Transmit Focusing and Filter-derived Coherence-Index\nWeighting. in Proc. IEEE Ultrason. Symp., 2010.","Chi Hyung. Seo and Jesse T. Yen, Sidelobe Suppression in Ultrasound\nImaging using Dual Apodization with Cross-correlation. IEEE Trans.\nUltras., Ferro., And Freq. Control., 55(10), 2198-2210,2008","J. A. Jensen,\" Field: A program for simulating ultrasound systems,\"\nMedical & Biological Engineering & Computing, vol. 34, pp. 351–353,\n1996."]}

Recently, a wide spectrum of new applications in biomedical ultrasound such as real time 3D ultrasound and transient elastography has triggered the need of high frame-rate imaging. One of the methods to achieve high frame-rate imaging is to use plane wave excitation (PWE) with which a single insonification is sufficient to form an image. However, due to the lack of transmit focusing, the signal-to-noise-ratio (SNR), contrast, and spatial resolution of the resultant images are lower compared with a conventional focused transmission. To solve this problem, we propose a filter-based retrospective focusing technique combined with filter-derived coherence-index weighting (FRF+FCI weighting) for high frame-rate imaging with PWE. A 2-D filter is designed and applied to beamformed baseband data to retrieve transmit focusing. Then a filter-derived coherence index (FCI) at each imaging point is used as a weighting factor to further improve the filter-retrieved focusing quality. Here FCI is a coherence measure of the filtered signal samples in the sliding filter kernel, Due to the sidelobe-suppression nature of the designed 2-D filter, FCIs are low at sidelobes; thus FCI weighting can further suppress the sidelobes in the filtered signal samples. Simulation results demonstrated that our proposed FRF+FCI weighting technique can enhance the image quality of high frame-rate imaging with single PWE — reducing the sidelobes, and improving the SNR and spatial resolution while being capable of retaining the high frame rate. Since it is applied over high frame-rate imaging with single PWE, FRF+FCI weighting performed after beamforming is inherently insusceptible to motion artifacts. In addition, coded excitation techniques can be integrated into our technique to further improve SNR.

This work proposes an innovative textile sensor system to monitor dynamic body movement and human posture by attaching wearable digital sensors to analyze body motion. The proposed system can display and analyze signals when individuals are walking, running, veering around, walking up and down stairs, as well as falling down with a wearable monitoring system, which reacts to the coordination between the body and feet. Several digital sensor designs are embedded in clothing and wear apparel. Any pressure point can determine which activity is underway. Importantly, wearable digital sensors and a wearable monitoring system allow adaptive, real-time postures, real time velocity, acceleration, non-invasive, transmission healthcare, and point of care (POC) for home and non-clinical environments.

To investigate the prevalence and correlation factors of carotid atherosclerosis (CAS) among workers of Chongqing Iron and Steel Corporation, and to offer information for the development of prevention program for cerebro-vascular disease.512 asymptomatic individuals (mean age 56.8 years, ranged from 45 to 80) from the subsidiary workshop of Chongqing Iron and Steel Corporation were recruited. Demographic data and serum were collected and the internal-media thickness (IMT) of the CAS and the extent of plaque formation were evaluated by B-mode ultrasound. Logistic regression analysis was used to estimate the correlation factors of CAS. Results (1) The overall prevalence of carotid atherosclerosis among the iron and steel workers was 37.6%. IMT was found as 10.2% , with the prevalence rates of nonstenotic plaque and stenotic plaque were 25.0% and 2.4% respectively. (2) It was shown by logistic regression analysis that age (OR = 1.289, 95% CI: 1.014-1.568, P0.001), smoking (OR = 1.420, 95% CI: 0.802-3.872, P0.001), hypertension (OR= 4.530, 95% CI: 3.952-6.753, P0.001) , diabetes mellitus (OR = 2.285, 95% CI: 1.008-5.057, P0.001), HsCRP (OR = 1.273, 95% CI: 0.479-2.889, P = 0.037), TC (OR = 1.032, 95% CI: 0.320-1.882, P = 0.047) and LDL-C (OR = 2.313, 95% CI: 1.237-4.331, P = 0.008) were significantly associated with the severity of CAS. (3) Prevalence of the CAS increased with the increasing number of correlation factors.The prevalence of CAS among the iron and steel workers was higher than those in ordinary people of the same age. Age, smoking, hypertension, diabetes mellitus, HsCRP, TC and LDL-C were independent risk factors related to CAS. The prevalence of CAS was increasing parallel to the number of correlation factors.

To construct a recombinant adenoviral vector carrying HIF-1alpha gene and explore the therapeutic effect of HIF-1alpha on focal cerebral ischemia in adult rats.The AdEasy System was used to construct the recombinant adenoviral vector carrying HIF-1alpha gene and green fluorescent protein and PCR was used to identify the HIF-1alpha gene. Middle cerebral artery occlusion (MCAo) and reperfusion models were established and divided into Ad-HIF-1alpha group, Ad group and NS group. After Ad-HIF-1alpha, Ad and NS were injected into the ischemic ventricle, expression of Ad-HIF-1alpha was observed and its therapeutic effect was evaluated by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining and neurological severity scores.GFP expression distributed apart from the ventricle and reached a peak at 14 days and persisted for about 4 weeks under fluorescent microscope. The neurological severity scores was 2.4 +/- 0.5 at 24 h in Ad-HIF-1alpha group and there was no statistical significance compared with Ad group (2.6 +/- 0.5) and NS group (2.7 +/- 0.7) (P0.05). The scores were 1.6 +/- 0.7 at 48 h and 0.9 +/- 0.6 at 72 h in Ad-HIF-1alpha group, and there were statistical significance compared with Ad group (2.9 +/- 0.6 and 3.2 +/- 0.6 respectively) and NS group (3.0 +/- 0.7 and 3.2 +/- 0.8) (P0.05). The infarct volume was 81.2 mm(3) +/- 1.4 mm(3) at 72 h in Ad-HIF-1alpha group and there was statistical significance compared with Ad group (173.9 mm(3) +/- 1.3 mm(3)) and NS group (171.7 mm(3) +/- 6.2 mm(3)) (P0.05).HIF-1alpha gene had definite therapeutic effect on focal cerebral ischemia in adult rats, which settles a foundation for next HIF-1alpha gene study and clinic application.

To study the effect of Shuxuetong injection on cerebral tissue and brain microvascular endothelial cell(BMEC) in secreting tissue-type plasminogen activator (tPA).The experiment in vivo was designed for three groups: sham-operation group, focal cerebral ischemia model group, Shuxuetong injection-treated group. The gene expression and the activity of tPA on brains were detected by RT-PCR and chromogenic substrate analysis respectively after treatment for five days; The experiment in vitro: The cultured BMEC were divided into experimental group and control group. The Shuxuetong injection were added into experimental group and the BMECs in the experimatal groups were treated for 24 h. The gene expression and the activity of tPA on cultured BMEC were detected by RT-PCR and chromogenic substrate analysis respectively.The gene expression and the content of tPA on both cerebral tissue and BMEC in the experimatal groups were significantly higher than that in the control groups.Shuxuetong injection could accelerate secretion of tPA, and therefore enhance fibrinolysis.