| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Sun, Xiaoming, et al.
(författare)
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Adjustable hardness of hydrogel for promoting vascularization and maintaining sternness of stem cells in skin flap regeneration
- 2018
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Ingår i: Applied Materials Today. - : Elsevier. - 2352-9407. ; 13, s. 54-63
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Tidskriftsartikel (refereegranskat)abstract
- The matrix mechanical stiffness of biomaterials plays an important role in the pluripotency and biological function of stem cells in the microenvironment. It is a key step to adjust the stiffness of biomaterials for inducing stem cells to promote vascularization in order to promote damaged tissue repair. In this study, we transplant adipose derived stem cells (ADSCs) within an in situ forming dextran hydrogel with controllable mechanical strength formed by cross-linking glycidyl methacrylate derivatized dextran and dithiothreitol, which can regulate the stemness and biological functions of stem cells. We show that softer dextran hydrogel can better maintain stemness markers expression of ADSCs, and significantly stimulate ADSCs to secrete angiogenic factors. The ADSCs-encapsulated hydrogel distinctly promote the skin flap survival compared to direct cell injection. Bioluminescence imaging analysis shows that in situ forming dextran hydrogel can improve cells retention, and postmortem analysis reveals that the transplanted ADSCs with hydrogel can promote vascularization. These results support the use of injectable dextran hydrogel for skin ischemia tissue regeneration. (C) 2018 Elsevier Ltd. All rights reserved.
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| 3. |
- Gong, Zijun, et al.
(författare)
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Smart AUV-Assisted Localization and Time Synchronization of Underwater Acoustic Devices
- 2022
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Ingår i: Smart Ships. - Boca Raton : CRC Press. - 9781003025924 ; , s. 133-168
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The localization and time synchronization of Underwater Acoustic Devices (UADs) have many potential applications in industry and scientific research. This can be done by deploying location-aware fixed anchors on the sea surface or bottom. However, this solution has poor accuracy and induces huge costs. In recent years, with the surge of Autonomous Underwater Vehicles (AUVs), the possibility of employing smart AUVs as mobile anchors have been extensively discussed. In this chapter, three smart AUV-assisted underwater localization and time synchronization techniques will be introduced, based on ToA (Time of Arrival), Doppler shift, and linear frequency modulated signals. The system model will be presented in detail, and the corresponding algorithms will be briefly discussed. For each of them, some preliminary numerical evaluations are conducted to directly show their performance.
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| 4. |
- Su, Ruoyu, et al.
(författare)
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A Mobile Node Assisted Localization System for Wireless Sensor Networks
- 2021
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Ingår i: IWCMC 2021: 2021 17TH INTERNATIONAL WIRELESS COMMUNICATIONS & MOBILE COMPUTING CONFERENCE (IWCMC). - 2376-6492. - 9781728186160 ; , s. 1716-1720
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Konferensbidrag (refereegranskat)abstract
- Wireless sensor network (WSN), consisting of several sensor nodes, is one of the most promising technologies emerged in the past decade. The positioning system for WSN is particularly meaningful and widely used in the military surveillance, air-sea rescue, traffic monitoring, and etc. However, the traditional positioning system always suffers from deployment and maintenance of anchors. In this paper, we propose a positioning system employing a Raspberry Pi platform attached to a DJI drone as a mobile anchor. The DJI drone can serve as multiple virtual anchors by moving and broadcasting its location information periodically. Thus, it is possible to localize sensor node by itself when the sensor node collects the drone's position. A Gauss-Newton method is applied to improve the accuracy of the proposed positioning system. We also elaborate the adaption of the Gauss-Newton method with the geodetic coordinates. The goal of the proposed positioning system is to achieve higher accuracy and higher coverage at lower cost.
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| 5. |
- Su, Ruoyu, et al.
(författare)
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Analysis of Outage Probability for Millimeter Wave Communications
- 2021
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Ingår i: IWCMC 2021: 2021 17TH INTERNATIONAL WIRELESS COMMUNICATIONS & MOBILE COMPUTING CONFERENCE (IWCMC). - 2376-6492. - 9781728186160 ; , s. 2194-2198
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Konferensbidrag (refereegranskat)abstract
- As the data traffic in future wireless communications will explosively grow up to 1000-fold by the deployment of 5G, several technologies are emerging to satisfy this demand, including multiple-input multiple-output (MIMO), millimeter wave communications, Non-orthogonal Multiple Access (NOMA), etc. Millimeter wave communication is a promising solution since it can provide tens of GHz bandwidth by fundamentally exploring higher unoccupied spectrum resources. As the wavelength of higher frequency shrinks, it is possible to design more compact antenna array with large number of antennas with independent RF (Radio Frequency) chains, causing high cost and complexity. By exploring the spatial sparsity of the millimeter wave channels, lens antenna array has been investigated recently as a promising choice with limited RF chains and low complexity. In this paper, we investigate the outage probability for highway communication systems with lens antenna array, under overtaking scenario, where high mobility of users is expected. When a vehicle is trying to pass another one, the channels between these two vehicles and the RSU (Road Side Unit) are unresolvable, thus causing outage for at least tens of symbol durations. We apply power-domain NOMA in this scenario, where these two users are paired by a threshold derived with the QoS of each user, to alleviate this problem and achieve low outage probability.
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