| 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. |
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
- Chen, Jun-Tong, et al.
(författare)
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Corydalis sunhangii (Papaveraceae) : A new species from Xizang, China, based on plastome and morphological data
- 2024
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- A new species of Papaveraceae, Corydalis sunhangii, in the section Trachycarpae, is described and illustrated from Nyingchi City, Xizang, China. The new species has some resemblance to Corydalis kingdonis, but differs by radical leaves prominent, usually several, blade tripinnate (vs. insignificant, few, blade bi- to triternate); cauline leaf usually one, much smaller than radical leaves, usually situated in lower half of stem (vs. usually two, larger than radical leaves, concentrated in upper third of stem); racemes densely 13-35-flowered (vs. rather lax, 4-11-flowered); claw of lower petal shallowly saccate (vs. very prominently and deeply saccate); capsule oblong, with raised lines of dense papillae (vs. broadly obovoid, smooth). Phylogenetic analysis, based on 68 protein-coding plastid genes of 49 samples, shows that C. sunhangii is not closely related to any hitherto described species, which is consistent with our morphological analysis.
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| 5. |
- Liu, Wei, et al.
(författare)
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Coherent dynamics of multi-spin V-B(-) center in hexagonal boron nitride
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Hexagonal boron nitride (hBN) has recently been demonstrated to contain optically polarized and detected electron spins that can be utilized for implementing qubits and quantum sensors in nanolayered-devices. Understanding the coherent dynamics ofmicrowave driven spins in hBN is of crucial importance for advancing these emerging new technologies. Here, we demonstrate and study the Rabi oscillation and related phenomena of a negatively charged boron vacancy (V-B(-)) spin ensemble in hBN. We report on different dynamics of the V-B(-) spins at weak and strong magnetic fields. In the former case the defect behaves like a single electron spin system, while in the latter case it behaves like a multi-spin system exhibiting multiple-frequency dynamical oscillation as beat in the Ramsey fringes. We also carry out theoretical simulations for the spin dynamics of V-B(-) and reveal that the nuclear spins can be driven via the strong electron nuclear coupling existing in V-B(-) center, which can be modulated by the magnetic field and microwave field.
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| 6. |
- Quan, Yu, et al.
(författare)
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A Double-layer Multibeam Antenna with 45° Linear Polarization Based on Gap Waveguide Technology
- 2022
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:1, s. 56-66
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a double-layer 1-D multibeam antenna based on gap waveguide (GWG) technology is proposed. The bottom layer is the beamforming network (BFN), which is composed of four cruciform couplers and two -45° phase shifters realized by groove gap waveguides. Four output ports of the BFN are connected to the slot arrays on the top layer through 180° E-plane bends. The output amplitudes of the BFN are -6.3 ± 0.5 dB and the phase errors are within ± 14° from 26 to 32 GHz with a bandwidth of 20%. To relieve the grating lobe problem, groove gap waveguides are transited to ridge gap waveguides on the top layer and the slot array is fed from ridge gap waveguides. Due to the topology of the BFN, the slot array is oriented along the diagonal plane and as a result, the multibeam antenna is 45° linearly polarized. To handle the dip emerging in the side beam caused by the finite ground of the BFN, several metal fences working as a soft surface are applied to suppress the edge diffractions. Besides, the gain is increased by 0.78 dB compared to the case without metal fences at 29 GHz. Thanks to the low-loss property of gap waveguide technology, high gain and high radiation efficiency are obtained. The maximum gain is 17.46 dBi with the beam direction at -11° for Port 1 and 16.51 dBi with the beam direction at 37° for Port 2. The simulated radiation efficiency is above 97% for both Port 1 and Port 2.
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| 7. |
- Quan, Yu, 1994, et al.
(författare)
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A Simple Asymmetric Orthomode Transducer Based on Groove Gap Waveguide
- 2020
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 30:10, s. 953-956
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Tidskriftsartikel (refereegranskat)abstract
- The groove gap waveguide (GGWG) technology is used to design a simple asymmetric orthomode transducer (OMT) at the Ka-band in this letter. The OMT consists of two metal layers which do not need electrical contact due to the property of the gap waveguide technology. The vertical polarization (VP) is directly fed to a standard rectangular waveguide port from the main arm of a square waveguide, while the horizontal polarization (HP) is fed to the side arm by an H-bend. No septum or iris is needed, which contributes to a simple structure. The OMT has been manufactured and measured using a back-to-back setup. A high isolation of over 40 dB is achieved within the working band from 26.1 to 29.3 GHz. The reflection coefficient is below -11.4 and -17.7 dB for the HP and VP, respectively. The higher return loss of the HP is caused mainly by the manufacturing errors. Nevertheless, the insertion loss for both polarizations is below 0.25 dB for a single OMT.
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| 8. |
- Quan, Yu, et al.
(författare)
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A Wideband End-fire Double Dipole Antenna Fed from Double-ridge Gap Waveguides for Multibeam Array Application
- 2022
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 21:4, s. 760-764
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, an end-fire double dipole antenna fed from double-ridge gap waveguides (DRGWG) is proposed and designed for multibeam array application. Two dipoles with different lengths are connected to the extension of the ridges of DRGWG in series. Different resonances can be generated by these two dipoles, which contributes to a wide impedance bandwidth, high gain and stable radiation patterns across the working band. The double dipole antenna is vertically polarized and has a wide H-plane beam width suitable for beam scanning application. To verify the performance of the double dipole antenna, a butler matrix is designed based on ridge gap waveguides (RGWG) to feed a 1*4 double dipole array arranging in H-plane. The maximum gains achieved for Port 1 and Port 2 are 13.94 dBi and 12.68 dBi respectively. Besides, the simulated radiation efficiencies for Port 1 and Port 2 are both above 94%.
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| 9. |
- Quan, Yu, 1994, et al.
(författare)
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An Unequal Power Divider Based on Ridge Gap Waveguide
- 2019
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Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019.
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a novel unequal power divider based on the ridge gap waveguide technology. Different from the conventional T-junction power divider, the unequal power divider is realized by using a half-height pin structure with an inserted conductor plane. The conductor plane is printed on a thin substrate for the mechanical feasibility. The power division ratio can be controlled by the position of the inserted conductor plane. In this paper, a 1:2 power divider is designed to verify this topology. The reflection coefficient is below -20 dB from 26 GHz to 32 GHz with 20.7% impedance bandwidth and the amplitude discrepancy between the two output ports is about 2.92 dB. Meanwhile, the maximum value of the phase difference is below 12°.
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| 10. |
- Quan, Yu, et al.
(författare)
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An unequal power divider based on ridge gap waveguide with an inserted conductor plate
- 2021
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 63:2, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- A novel unequal power divider based on ridge gap waveguide is proposed and investigated in this paper. The half-height pin gap waveguide structure is applied to acquire the required stopband. The whole divider can be divided into three parts. The first part is the core of the divider which is a gap waveguide transmission line with a thin inserted conductor plate (ICP). The ICP is printed on a thin substrate for the mechanical feasibility and stability. The position of the ICP can be changed to adjust the power division ratio (PDR). The ICP separates the divider into two different layers. Then, the second and third parts are transitions from top layer and bottom layer to normal gap waveguide transmission lines. Two power dividers with different PDRs of 1:2 and 1:4 working at 28 GHz are designed and manufactured to verify this topology.
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