89 research outputs found

    Speckle reducing bilateral filter for cattle follicle segmentation

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Ultrasound imaging technology has wide applications in cattle reproduction and has been used to monitor individual follicles and determine the patterns of follicular development. However, the speckles in ultrasound images affect the post-processing, such as follicle segmentation and finally affect the measurement of the follicles. In order to reduce the effect of speckles, a bilateral filter is developed in this paper.</p> <p>Results</p> <p>We develop a new bilateral filter for speckle reduction in ultrasound images for follicle segmentation and measurement. Different from the previous bilateral filters, the proposed bilateral filter uses normalized difference in the computation of the Gaussian intensity difference. We also present the results of follicle segmentation after speckle reduction. Experimental results on both synthetic images and real ultrasound images demonstrate the effectiveness of the proposed filter.</p> <p>Conclusions</p> <p>Compared with the previous bilateral filters, the proposed bilateral filter can reduce speckles in both high-intensity regions and low intensity regions in ultrasound images. The segmentation of the follicles in the speckle reduced images by the proposed method has higher performance than the segmentation in the original ultrasound image, and the images filtered by Gaussian filter, the conventional bilateral filter respectively.</p

    Arsenic speciation in saliva of acute promyelocytic leukemia patients undergoing arsenic trioxide treatment

    Get PDF
    Arsenic trioxide has been successfully used as a therapeutic in the treatment of acute promyelocytic leukemia (APL). Detailed monitoring of the therapeutic arsenic and its metabolites in various accessible specimens of APL patients can contribute to improving treatment efficacy and minimizing arsenic-induced side effects. This article focuses on the determination of arsenic species in saliva samples from APL patients undergoing arsenic treatment. Saliva samples were collected from nine APL patients over three consecutive days. The patients received 10 mg arsenic trioxide each day via intravenous infusion. The saliva samples were analyzed using high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry. Monomethylarsonous acid and monomethylmonothioarsonic acid were identified along with arsenite, dimethylarsinic acid, monomethylarsonic acid, and arsenate. Arsenite was the predominant arsenic species, accounting for 71.8 % of total arsenic in the saliva. Following the arsenic infusion each day, the percentage of methylated arsenicals significantly decreased, possibly suggesting that the arsenic methylation process was saturated by the high doses immediately after the arsenic infusion. The temporal profiles of arsenic species in saliva following each arsenic infusion over 3 days have provided information on arsenic exposure, metabolism, and excretion. These results suggest that saliva can be used as an appropriate clinical biomarker for monitoring arsenic species in APL patients. [Figure: see text

    Evaluation of the pore morphologies for piezoelectric energy harvesting application

    Get PDF
    Piezoelectric energy harvesting has attracted significant attention in recent years due to their high-power density and potential applications for self-powered sensor networks. In comparison to dense piezoelectric ceramics, porous piezoelectric ceramics exhibit superiority due to an enhancement of piezoelectric energy harvesting figure of merit. This paper provides a detailed examination of the effect of pore morphology on the piezoelectric energy harvesting performance of porous barium calcium zirconate titanate 0.5Ba(Zr0.2 Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT) ceramics. Three different pore morphologies of spherical, elliptical, and aligned lamellar pores were created via the burnt-out polymer spheres method and freeze casting. The relative permittivity decreased with increasing porosity volume fraction for all porous BCZT ceramics. Both experimental and simulation results demonstrate that porous BCZT ceramics with aligned lamellar pores exhibit a higher remanent polarization. The longitudinal d33 piezoelectric charge coefficient decreased with increasing porosity volume fraction for the porous ceramics with three different pore morphologies; however, the rate of decrease in d33 with porosity is slower for aligned lamellar pores, leading to the highest piezoelectric energy harvesting figure of merit. Moreover, the peak power density of porous BCZT ceramics with aligned lamellar pores is shown to reach up to 38 μW cm-2 when used as an energy harvester, which is significantly higher than that of porous BCZT ceramics with spherical or elliptical pores. This work is beneficial for the design and manufacture of porous ferroelectric materials in devices for piezoelectric energy harvesting applications.</p

    The effects of tai chi on markers of atherosclerosis, lower-limb physical function, and cognitive ability in adults aged over 60: A randomized controlled trial

    Get PDF
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Objective: The purpose of this study was to investigate the effects of Tai Chi (TC) on arterial stiffness, physical function of lower-limb, and cognitive ability in adults aged over 60. Methods: This study was a prospective and randomized 12-week intervention trial with three repeated measurements (baseline, 6, and 12 weeks). Sixty healthy adults who met the inclusion criteria were randomly allocated into three training conditions (TC-24, TC-42, and TC-56) matched by gender, with 20 participants (10 males, 10 females) in each of the three groups. We measured the following health outcomes, including markers of atherosclerosis, physical function (leg power, and static and dynamic balance) of lower-limb, and cognitive ability. Results: When all three TC groups (p \u3c 0.05) have showed significant improvements on these outcomes but overall cognitive ability at 6 or 12 weeks training period, TC-56 appears to have superior effects on arterial stiffness and static/dynamic balance in the present study. Conclusions: Study results of the present study add to growing body of evidence regarding therapeutic TC for health promotion and disease prevention in aging population. Future studies should further determine whether TC-42 and TC-56 are beneficial for other non-Chinese populations, with rigorous research design and follow-up assessment

    3D-Printed Flexible PVDF-TrFE Composites with Aligned BCZT Nanowires and Interdigital Electrodes for Piezoelectric Nanogenerator Applications

    Get PDF
    Piezoelectric nanogenerators based on piezoelectric nanocomposites have attracted much interest in recent decades owing to their excellent piezoelectric properties and application in self-powered systems and wearable sensors. As a promising piezoelectric ceramic filler in composite-based generators, one-dimensional (1D) piezoelectric nanowires were filled into a polymer matrix to enhance its dielectric and piezoelectric properties. In this paper, flexible PVDF-TrFE composite films containing highly aligned Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZT) nanowires (NWs) have been manufactured via a direct-ink writing method. The effect of BCZT NW content on the dielectric, ferroelectric, and piezoelectric properties was investigated using multiphysics modeling and detailed experiments. An optimum composite composition was discovered, and the piezoelectric composite film with 15 wt % BCZT NWs possessed the highest energy harvesting figure of merit of 5.3 × 10-12 m2/N. Interdigital electrodes were combined with the composite to fabricate a patterned piezoelectric nanogenerator, where the piezoelectric nanogenerator can produce an open-circuit output voltage of 17 V, and the maximum output power density could reach 5.6 μW/cm2. This work provides opportunities for the optimization and fabrication of piezoelectric materials for energy-harvesting and sensing applications.</p

    Enhanced energy harvesting performance in lead-free multi-layer piezoelectric composites with a highly aligned pore structure

    Get PDF
    The harvesting of mechanical energy from our living environment via piezoelectric energy harvesters to provide power for next generation wearable electronic devices and sensors has attracted significant interest in recent years. Among the range of available piezoelectric materials, porous piezoelectric ceramics exhibit potential for both sensing and energy harvesting applications due to their reduced relative permittivity and enhanced piezoelectric sensing and energy harvesting figures of merit. Despite these developments, the low output power density and the lack of optimized structural design continues to restrict their application. Here, to overcome these challenges, a lead-free multi-layer porous piezoelectric composite energy harvester with a highly aligned pore structure and three-dimensional intercalation electrodes is proposed, fabricated and characterized. The effect of material structure and multi-layer configuration of the porous piezoelectric ceramic on the dielectric properties, piezoelectric response and energy harvesting performance was investigated in detail. Since the relative permittivity is significantly reduced due to the introduction of aligned porosity within the multi-layer structure, the piezoelectric voltage coefficient, energy harvesting figure of merit and output power are greatly enhanced. The multi-layer porous piezoelectric composite energy harvester is shown to generate a maximum output current of 80 μA, with a peak power density of 209 μW cm−2, which is significantly higher than other porous piezoelectric materials reported to date. Moreover, the generated power can charge a 10 μF capacitor from 0 V to 4.0 V in 150 s. This work therefore provides a new strategy for the design and manufacture of porous piezoelectric materials for piezoelectric sensing and energy harvesting applications.</p
    corecore