Multifunctional microbubbles and nanobubbles for photoacoustic and ultrasound imaging

We develop a novel dual-modal contrast agent—encapsulated-ink poly(lactic-co-glycolic acid) (PLGA) microbubbles and nanobubbles—for photoacoustic and ultrasound imaging. Soft gelatin phantoms with embedded tumor simulators of encapsulated-ink PLGA microbubbles and nanobubbles in various concentrations are clearly shown in both photoacoustic and ultrasound images. In addition, using photoacoustic imaging, we successfully image the samples positioned below 1.8-cm-thick chicken breast tissues. Potentially, simultaneous photoacoustic and ultrasound imaging enhanced by encapsulated-dye PLGA microbubbles or nanobubbles can be a valuable tool for intraoperative assessment of tumor boundaries and therapeutic margins

Fabricating multifunctional microbubbles and nanobubbles for concurrent ultrasound and photoacoustic imaging

Background: Clinical ultrasound (US) uses ultrasonic scattering contrast to characterize subcutaneous anatomic structures. Photoacoustic (PA) imaging detects the functional properties of thick biological tissue with high optical contrast. In the case of image-guided cancer ablation therapy, simultaneous US and PA imaging can be useful for intraoperative assessment of tumor boundaries and ablation margins. In this regard, accurate co-registration between imaging modalities and high sensitivity to cancer cells are important. Methods: We synthesized poly-lactic-co-glycolic acid (PLGA) microbubbles (MBs) and nanobubbles (NBs) encapsulating India ink or indocyanine green (ICG). Multiple tumor simulators were fabricated by entrapping ink MBs or NBs at various concentrations in gelatin phantoms for simultaneous US and PA imaging. MBs and NBs were also conjugated with CC49 antibody to target TAG-72, a human glycoprotein complex expressed in many epithelial-derived cancers. Results: Accurate co-registration and intensity correlation were observed in US and PA images of MB and NB tumor simulators. MBs and NBs conjugating with CC49 effectively bound with over-expressed TAG-72 in LS174T colon cancer cell cultures. ICG was also encapsulated in MBs and NBs for the potential to integrate US, PA, and fluorescence imaging. Conclusions: Multifunctional MBs and NBs can be potentially used as a general contrast agent for multimodal intraoperative imaging of tumor boundaries and therapeutic margins

Multifunctional microbubbles and nanobubbles for photoacoustic and ultrasound imaging

We develop a novel dual-modal contrast agent—encapsulated-ink poly(lactic-co-glycolic acid) (PLGA) microbubbles and nanobubbles—for photoacoustic and ultrasound imaging. Soft gelatin phantoms with embedded tumor simulators of encapsulated-ink PLGA microbubbles and nanobubbles in various concentrations are clearly shown in both photoacoustic and ultrasound images. In addition, using photoacoustic imaging, we successfully image the samples positioned below 1.8-cm-thick chicken breast tissues. Potentially, simultaneous photoacoustic and ultrasound imaging enhanced by encapsulated-dye PLGA microbubbles or nanobubbles can be a valuable tool for intraoperative assessment of tumor boundaries and therapeutic margins

REFUGE Challenge: A unified framework for evaluating automated methods for glaucoma assessment from fundus photographs

[EN] Glaucoma is one of the leading causes of irreversible but preventable blindness in working age populations. Color fundus photography (CFP) is the most cost-effective imaging modality to screen for retinal disorders. However, its application to glaucoma has been limited to the computation of a few related biomarkers such as the vertical cup-to-disc ratio. Deep learning approaches, although widely applied for medical image analysis, have not been extensively used for glaucoma assessment due to the limited size of the available data sets. Furthermore, the lack of a standardize benchmark strategy makes difficult to compare existing methods in a uniform way. In order to overcome these issues we set up the Retinal Fundus Glaucoma Challenge, REFUGE (https://refuge.grand-challenge.org), held in conjunction with MIC-CAI 2018. The challenge consisted of two primary tasks, namely optic disc/cup segmentation and glaucoma classification. As part of REFUGE, we have publicly released a data set of 1200 fundus images with ground truth segmentations and clinical glaucoma labels, currently the largest existing one. We have also built an evaluation framework to ease and ensure fairness in the comparison of different models, encouraging the development of novel techniques in the field. 12 teams qualified and participated in the online challenge. This paper summarizes their methods and analyzes their corresponding results. In particular, we observed that two of the top-ranked teams outperformed two human experts in the glaucoma classification task. Furthermore, the segmentation results were in general consistent with the ground truth annotations, with complementary outcomes that can be further exploited by ensembling the results.This work was supported by the Christian Doppler Research Association, the Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research, Technology and Development, J.I.O is supported by WWTF (Medical University of Vienna: AugUniWien/FA7464A0249, University of Vienna: VRG12- 009). Team Masker is supported by Natural Science Foundation of Guangdong Province of China (Grant 2017A030310647). Team BUCT is partially supported by the National Natural Science Foundation of China (Grant 11571031). The authors would also like to thank REFUGE study group for collaborating with this challenge.Orlando, JI.; Fu, H.; Breda, JB.; Van Keer, K.; Bathula, DR.; Diaz-Pinto, A.; Fang, R.... (2020). 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Informing the Design of Privacy-Empowering Tools for the Connected Home

Connected devices in the home represent a potentially grave new privacy threat due to their unfettered access to the most personal spaces in people's lives. Prior work has shown that despite concerns about such devices, people often lack sufficient awareness, understanding, or means of taking effective action. To explore the potential for new tools that support such needs directly we developed Aretha, a privacy assistant technology probe that combines a network disaggregator, personal tutor, and firewall, to empower end-users with both the knowledge and mechanisms to control disclosures from their homes. We deployed Aretha in three households over six weeks, with the aim of understanding how this combination of capabilities might enable users to gain awareness of data disclosures by their devices, form educated privacy preferences, and to block unwanted data flows. The probe, with its novel affordances-and its limitations-prompted users to co-adapt, finding new control mechanisms and suggesting new approaches to address the challenge of regaining privacy in the connected home.Comment: 10 pages, 2 figures. To appear in the Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems (CHI '20

Limb development genes underlie variation in human fingerprint patterns

Fingerprints are of long-standing practical and cultural interest, but little is known about the mechanisms that underlie their variation. Using genome-wide scans in Han Chinese cohorts, we identified 18 loci associated with fingerprint type across the digits, including a genetic basis for the long-recognized “pattern-block” correlations among the middle three digits. In particular, we identified a variant near EVI1 that alters regulatory activity and established a role for EVI1 in dermatoglyph patterning in mice. Dynamic EVI1 expression during human development supports its role in shaping the limbs and digits, rather than influencing skin patterning directly. Trans-ethnic meta-analysis identified 43 fingerprint-associated loci, with nearby genes being strongly enriched for general limb development pathways. We also found that fingerprint patterns were genetically correlated with hand proportions. Taken together, these findings support the key role of limb development genes in influencing the outcome of fingerprint patterning

WizNet: A ZigBee-based sensor system for distributed wireless LAN performance monitoring

802.11-based wireless LANs (WLANs) have become an important communication infrastructure for today's pervasive computing applications. Nevertheless, WLAN users often experience various performance issues such as highly variable signal quality. To diagnose such transient service degradations and plan for future network upgrades, it is essential to closely monitor the performance of a WLAN and collect user statistics. This paper proposes a new WLAN performance monitoring approach motivated by the fact that many low-power wireless technologies such as ZigBee and Bluetooth co-exist with WLAN in the same open radio spectrum and are capable of sensing Received Signal Strength (RSS) of 802.11 transmissions. We have developed a ZigBee-based WLAN monitoring system called WizNet. Powered by batteries, ZigBee sensors of WizNet can be deployed in large quantities to monitor the spatial performance of a WLAN in long periods of time. By adopting digital signal processing techniques, WizNet automatically identifies 802.11 signals from ZigBee RSS measurements and associates them with wireless access points. To ensure the monitoring fidelity, WizNet accounts for the significant differences in ZigBee and WLAN radios, such as bandwidth and susceptibility to multipath and frequency-selective fading. A simple yet accurate linear estimator derived from a signal propagation model is used to infer the access points' signal to noise ratio (SNR). Moreover, WizNet can measure the congestion level of the channel and detect rogue APs. WizNet can also collect WLAN client statistics and classify device models based on RSS signatures of 802.11 access point scans. We have implemented WizNet in TinyOS 2.x and extensively evaluated its performance on a wireless testbed. Our results over a period of 140 hours show that WizNet can accurately capture the spatial and temporal performance variability of a large-scale production WLAN. © 2013 IEEE

Finite Element Analysis of Stress on Cross-Wavy Primary Surface Recuperator Based on Thermal-Structural Coupling Model

In order to study the stress, strain and deformation of the recuperator, the thermal-structural coupling finite element analysis model of cross-wavy primary surface recuperator of gas microturbine was established. The stress of cross-wavy primary surface recuperator after operation under design conditions was analyzed by finite element method. The reliability of the material selected for the recuperator was verified, and the effects of pressure ratio and gas inlet temperature on stress and displacement of the recuperator were analyzed. The research results show that the maximum stress and strain on the gas outlet side of the recuperator are higher than the maximum stress and strain on the gas inlet side when only pressure is considered, and the result is the opposite when pressure and thermal stress are considered. The air passage of the recuperator deforms to the side of the gas passage, the air passage becomes larger, and the gas passage shrinks. With the increase of pressure ratio between air side and gas side, the maximum stress of recuperator passage also increases. When the pressure ratio increases to 8.4, the strength limit of the heat exchange fin material is reached. When the gas and air outlet temperatures remain unchanged and the thermal ratio decreases, as the gas inlet temperature increases, the maximum stress increases. For every 50 K increase in the gas inlet temperature, the maximum stress of the recuperator increases by about 2.3 MPa. The research results can be used to guide the designing and optimization of recuperator

Micro-/nano-topography of selective laser melting titanium enhances adhesion and proliferation and regulates adhesion-related gene expressions of human gingival fibroblasts and human gingival epithelial cells

Background: Selective laser melting (SLM) titanium is an ideal option to manufacture customized implants with suitable surface modification to improve its bioactivity. The peri-implant soft tissues form a protective tissue barrier for the underlying osseointegration. Therefore, original microrough SLM surfaces should be treated for favorable attachment of surrounding soft tissues. Material and methods: In this study, anodic oxidation (AO) was applied on the microrough SLM titanium substrate to form TiO2 nanotube arrays. After that, calcium phosphate (CaP) nanoparticles were embedded into the nanotubes or the interval of nanotubes by electrochemical deposition (AOC). These two samples were compared to untreated (SLM) samples and accepted mechanically polished (MP) SLM titanium samples. Scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, surface roughness, and water contact angle measurements were used for surface characterization. The primary human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs) were cultured for cell assays to determine adhesion, proliferation, and adhesion-related gene expressions. Results: For HGECs, AOC samples showed significantly higher adhesion, proliferation, and adhesion-related gene expressions than AO and SLM samples (P<0.05) and similar exceptional ability in above aspects to MP samples. At the same time, AOC samples showed the highest adhesion, proliferation, and adhesion-related gene expressions for HGFs (P<0.05). Conclusion: By comparison between each sample, we could confirm that both anodic oxidation and CaP nanoparticles had improved bioactivity, and their combined utilization may likely be superior to mechanical polishing, which is most commonly used and widely accepted. Our results indicated that creating appropriate micro-/nano-topographies can be an effective method to affect cell behavior and increase the stability of the peri-implant mucosal barrier on SLM titanium surfaces, which contributes to its application in dental and other biomedical implants