4,547 research outputs found

    Leukoaraiosis is associated with pneumonia after acute ischemic stroke

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    Diagnostic criteria for stroke associated pneumonia based on the CDC criteria. (DOCX 25 kb

    Cardiac Angiosarcoma on the Right Atrium: Two Cases

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    We detected two cases of right atrial angiosarcoma that had a similar appearance on imaging studies. Although the surgical findings were similar for the two patients, one had a clear resection margin, while the other had tumor cells in the resection margin on frozen biopsy. We suggest that preoperative data on magnetic resonance imaging and computed tomography in patients with angiosarcomas may not predict the exact extent of surgical resection or prognostic outcomes

    Method and and apparatus for processing a signal

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    A method of processing a signal is disclosed. The present invention includes receiving (a) downmix signal being generated from plural-channel signal and (b) spatial information indicating attribute of the plural-channel signal in order to upmix the downmix signal and including phase shift flag indicating whether phase of a frame of at least one channel of the plural-channel signal is shifted; obtaining inter-channel phase difference (IPD) coding flag indicating whether IPD value is used to the spatial information from a header of the spatial information; obtaining IPD mode flag indicating whether the IPD value is used to frame of the spatial information from the frame based on the IPD coding flag; obtaining the IPD value of parameter band in the frame, based on the IPD mode flag; upmixing plural-channel signal by applying the IPD value to the downmix signal; and shifting the phase of the frame of the at least one channel of the plural-channel signal based on the phase shift flag

    Highly precise AMCW time-of-flight scanning sensor based on digital-parallel demodulation

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    In this paper, a novel amplitude-modulated continuous wave (AMCW) time-of-flight (ToF) scanning sensor based on digital-parallel demodulation is proposed and demonstrated in the aspect of distance measurement precision. Since digital-parallel demodulation utilizes a high-amplitude demodulation signal with zero-offset, the proposed sensor platform can maintain extremely high demodulation contrast. Meanwhile, as all cross correlated samples are calculated in parallel and in extremely short integration time, the proposed sensor platform can utilize a 2D laser scanning structure with a single photo detector, maintaining a moderate frame rate. This optical structure can increase the received optical SNR and remove the crosstalk of image pixel array. Based on these measurement properties, the proposed AMCW ToF scanning sensor shows highly precise 3D depth measurement performance. In this study, this precise measurement performance is explained in detail. Additionally, the actual measurement performance of the proposed sensor platform is experimentally validated under various conditions

    Automatic Internal Stray Light Calibration of AMCW Coaxial Scanning LiDAR Using GMM and PSO

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    In this paper, an automatic calibration algorithm is proposed to reduce the depth error caused by internal stray light in amplitude-modulated continuous wave (AMCW) coaxial scanning light detection and ranging (LiDAR). Assuming that the internal stray light generated in the process of emitting laser is static, the amplitude and phase delay of internal stray light are estimated using the Gaussian mixture model (GMM) and particle swarm optimization (PSO). Specifically, the pixel positions in a raw signal amplitude map of calibration checkboard are segmented by GMM with two clusters considering the dark and bright image pattern. The loss function is then defined as L1-norm of difference between mean depths of two amplitude-segmented clusters. To avoid overfitting at a specific distance in PSO process, the calibration check board is actually measured at multiple distances and the average of corresponding L1 loss functions is chosen as the actual loss. Such loss is minimized by PSO to find the two optimal target parameters: the amplitude and phase delay of internal stray light. According to the validation of the proposed algorithm, the original loss is reduced from tens of centimeters to 3.2 mm when the measured distances of the calibration checkboard are between 1 m and 4 m. This accurate calibration performance is also maintained in geometrically complex measured scene. The proposed internal stray light calibration algorithm in this paper can be used for any type of AMCW coaxial scanning LiDAR regardless of its optical characteristics

    Axillofemoral Bypass to Treat Severe Heart Failure Caused by Takayasu's Arteritis

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    Takayasu's arteritis is an inflammatory vasculitis that primarily affects the aorta and its major branches. Involvement of the thoracic and abdominal aortas, although rare, causes marked hypertension and may lead to severe heart failure. We report the improvement of cardiac function after axillofemoral bypass grafting in a 59-year-old woman who had this condition

    Uterine Artery Doppler Velocimetry During Mid-second Trimester to Predict Complications of Pregnancy Based on Unilateral or Bilateral Abnormalities

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    We performed this study to evaluate uterine artery Doppler velocimetry (UADV) measurement of unilateral or bilateral abnormalities as a predictor of complications in pregnancy during the mid-second trimester (20-24 weeks). We enrolled 1,090 pregnant women who had undergone UADV twice: once between the 20th and 24th week (1st stage) and again between the 28th and 32nd week (2nd stage) of pregnancy, and then delivered at Yonsei Medical Center. UADV was performed bilaterally. Follow-up UADV was performed between the 28th and 32nd week, and the frequencies of pregnancy-induced hypertension (PIH), fetal growth restriction (FGR), and preterm delivery (before 34 weeks of gestation) were determined. Chi-squared and t-tests were used where appropriate, with p < .05 considered significant. According to the results of UADV performed between 20-24 weeks of gestation, 825 women (75.7%) were included in the normal group, 196 (18.0%) in the unilateral abnormality group, and 69 (6.3%) in the bilateral abnormality group. The incidences of FGR were 8.0%, 10.2%, and 26.1%, and the incidences of PIH were 0.1%, 3.6%, and 14.5%, respectively. The incidence of PIH was significantly lower in the normal group. The incidences of preterm delivery were 2.2%, 5.6%, and 8.7%, respectively. PIH developed in 46.7% of patients with bilateral abnormal findings in both the 1st and 2nd stage tests, and developed in none of the patients with normal findings in both tests. Abnormal results found by UADV performed between the 20-24th weeks of pregnancy, such as high S/D ratios regardless of placental location and the presence of an early diastolic notch, were associated with significant increases in the incidences of intrauterine growth restriction (IUGR) and PIH. This was true for both bilateral and unilateral abnormalities. Abnormal findings in bilateral UADV during the second trimester especially warrant close follow up for the detection of subsequent development of pregnancy complications
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