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| 2. |
- 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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| 3. |
- Ching, Tao-Chung, et al.
(författare)
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The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:2
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Tidskriftsartikel (refereegranskat)abstract
- We present 850 mu m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and similar to 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.
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| 4. |
- Karoly, Janik, et al.
(författare)
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The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
- 2023
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 952:1
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Tidskriftsartikel (refereegranskat)abstract
- We present observations of polarized dust emission at 850 mu m from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (N-H2 similar to 10(22) - 10(23) cm(-2)) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to similar to 160 +/- 30 mu G in the main starless core and up to similar to 90 +/- 40 mu G in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvenic. We also present a new method of data reduction for these denser but fainter objects like starless cores.
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| 5. |
- Jia, Jing, et al.
(författare)
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Tunable Mid-Infrared Dispersive Wave Generation of High-Efficiency and Broadband in a Suspended Thin-Film Lithium-Niobate-on-Insulator Waveguide
- 2021
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 9, s. 38419-38426
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Tidskriftsartikel (refereegranskat)abstract
- A suspended thin-film lithium-niobate-on-insulator nano-waveguide (NanoLN) is designed, and tunable mid-infrared dispersivewave generation of high-efficiency and broadband is numerically studied on this designed platform. By hollowing out the silicon dioxide substrate between the NanoLN core and silicon wafer, the loss issue induced by mode leaking at mid-infrared region is eliminated. The second zero-dispersion wavelength of the suspended NanoLN is tailored to locate around 2 mu m wavelength, so that mode-locked fiber laser pump sources in this waveband can be conveniently leveraged to generate dispersive wave beyond 3 mu mwavelength. We show that dispersive wave at 3.16 mu m with high conversion efficiency up to 36.26% and bandwidth (at 10 dB level) of similar to 471 nm can be achieved at the pump pulse energy of 0.23 nJ. The central wavelength of the dispersive wave can be flexibly tuned up to 5 mu m with a maximum 10 dB bandwidth of similar to 2 mu m by lithographic control of the waveguide geometry, which is naturally at the expense of degraded conversion efficiency. Our results show the suspended NanoLN can provide a versatile chip-scale platform for cost-effective mid-infrared targetable, broadband, and coherent sources generation. Using fiber laser pump sources gives the advantages of compactness, free-maintenance, and long-term stability, which suit field applications.
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| 6. |
- Kang, Du Ho, et al.
(författare)
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Impact of asymmetric transmission power on operator competition in shared spectrum
- 2012
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Ingår i: Communication Technologies Workshop (Swe-CTW), 2012 Swedish. - : IEEE. - 9781467347631 ; , s. 25-29
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Konferensbidrag (refereegranskat)abstract
- To maintain affordable access for the rapidly increasing mobile traffic, base station deployment has to be tailored to hot-spot areas and primarily indoors where facility owners, e.g., shopping malls or hotels, mostly provide wireless service. Since such local access providers (LAPs) do not have access to exclusive spectrum, one proposed option is sharing spectrum with other nearby LAPs, e.g. unlicensed or secondary spectrum. Due to limited or no coordination between the LAPs, they selfishly access the spectrum, causing harmful interference to the neighboring networks. Especially by increasing transmission power, one operator may attempt to improve its own throughput at the expense of its neighbors. In this paper, we explore the impact of power asymmetry on competition between LAPs. We model the competition between two networks with different maximum power constraints as a network-wide power control game. By analyzing the pure Nash equilibria, we find that a lower power (LP) network becomes more aggressive to overcome the inter-network interference. Due to the aggressive behavior, sharing spectrum can out-perform fixed spectrum split even for the LP network, provided that the power asymmetry is below a certain limit. On the other hand, a higher power (HP) network is mainly affected by its own 'self-interference' so that it has little incentive to employ complicated inter-operator interference management schemes. In addition, we demonstrate that the power asymmetry limit strongly depends on the inter-network propagation conditions, e.g., inter-building distance or building penetration loss.
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| 7. |
- Liang, Lijun, et al.
(författare)
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Theoretical Evaluation on Potential Cytotoxicity of Graphene Quantum Dots
- 2016
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Ingår i: ACS Biomaterials Science & Engineering. - : AMER CHEMICAL SOC. - 2373-9878. ; 2:11, s. 1983-1991
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Tidskriftsartikel (refereegranskat)abstract
- Owing to unique morphology, ultrasmall lateral sizes, and exceptional properties, graphene quantum dots (GQDs) hold great potential in many applications, especially in the field of electrochemical biosensors, bioimaging, drug delivery, et cetera. Its biosafety and potential cytotoxicity to human and animal cells has been a growing concern in recent years. In this work, the potential cytotoxicity of GQDs was evaluated by molecular dynamics simulations. Our simulation demonstrates that small size GQDs could easily permeate into the lipid membrane in a vertical way. It is relatively difficult to permeate into the lipid membrane for GQDs that are larger than GQD61 on the nanosecond time-scale. The thickness of the POPC membrane could even be affected by the small size of GQDs. Free energy calculations revealed that the free energy barrier of GQD permeation through the lipid membrane could greatly change with the change of GQD size. Under high GQD concentration, the GQD molecules could rapidly aggregate in water but disaggregate after entering into the membrane interior. Moreover, high concentrations of GQDs could induce changes in the structure properties and diffusion properties of the lipid bilayer, and it may affect the cell signal transduction. However, GQDs with relatively small size are not large enough to mechanically damage the lipid membrane. Our results suggest that the cytotoxicity of GQDs with small size is low and may be appropriate for biomedical application.
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| 8. |
- Lin, Zongxing, et al.
(författare)
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Using Photonic Crystal Microrings to Mitigate Raman-Kerr Effects Competition for Soliton Microcomb Generation
- 2024
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 42:1, s. 268-275
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Tidskriftsartikel (refereegranskat)abstract
- In nonlinear microresonators with strong stimulated Raman scattering effect, it is difficult if not impossible to generate Kerr soliton microcombs with a small free spectral range (FSR) (< 100 GHz) due to the competition between the Raman and Kerr effects. In this article, we overcome this limitation by using odd-period photonic crystal microrings (PCMs). Numerical simulations on the silicon-on-insulator (SOI) PCM show that a small frequency shift (5 GHz) induced by the photonic crystal structure can moderately suppress the Raman effect, such that chaotic microcombs with a small FSR can be generated. With a larger frequency shift (e.g., >= 10 GHz), the Raman effect is significantly suppressed, and the soliton microcombs can be generated. For comparison, without the frequency shift, only Raman lasing can be achieved in a conventional microring. To investigate the applicability of the proposed method in other material platforms, we carried out simulations for the aluminium nitride (AlN) PCM. The results are comparable to those obtained on the SOI PCM. Our method opens a new approach to the generation of small FSR Kerr soliton microcombs in microresonators with strong Raman effect, which is important for expanding the available nonlinear platforms and applications such as telecommunications, radio-frequency photonics, and astronomical spectrographs.
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| 9. |
- Popovsk, Petar, et al.
(författare)
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EU FP7 INFSO-ICT-317669 METIS, D1.1 Scenarios, requirements and KPIs for 5G mobile and wireless system
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable introduces generic scenarios based on fundamental challenges, and the specific problem description of test cases that will be relevant for beyond future radio access. Specific characteristics of each scenario and each test case include the key assumptions regarding requirements and key performance indicators. In order not to constrain the potential solutions, the requirements are specified from an end-user perspective. The deliverable will not only serve as the guideline for the technical work and system concept design in METIS, but also can serve in external research communities to help to harmonize the work towards the future radio access system including the new generation system of 5G
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| 10. |
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