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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. |
- Jin, Ying-Hui, et al.
(författare)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
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Ingår i: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 4. |
- Barausse, Enrico, et al.
(författare)
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Prospects for fundamental physics with LISA
- 2020
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Ingår i: General Relativity and Gravitation. - : SPRINGER/PLENUM PUBLISHERS. - 0001-7701 .- 1572-9532. ; 52:8
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental physics. Given the very broad range of topics that might be relevant to LISA,we present here a sample of what we view as particularly promising fundamental physics directions. We organize these directions through a "science-first" approach that allows us to classify how LISA data can inform theoretical physics in a variety of areas. For each of these theoretical physics classes, we identify the sources that are currently expected to provide the principal contribution to our knowledge, and the areas that need further development. The classification presented here should not be thought of as cast in stone, but rather as a fluid framework that is amenable to change with the flow of new insights in theoretical physics.
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| 5. |
- Chen, Shao-Chun, et al.
(författare)
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First nationwide study regarding ceftriaxone resistance and molecular epidemiology of Neisseria gonorrhoeae in China
- 2016
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press. - 0305-7453 .- 1460-2091. ; 71:1, s. 92-99
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major public health concern worldwide. This is the first nationwide study, performed within the China Gonococcal Antimicrobial Susceptibility Programme (China-GASP), regarding AMR, including ceftriaxone genetic resistance determinants, and molecular epidemiology of gonococci in China.Methods: Gonococcal isolates (naEuroS=aEuroS1257) from consecutive patients were collected at 11 sentinel sites distributed across China during 2012-13. Susceptibility to ceftriaxone, spectinomycin, ciprofloxacin and tetracycline was determined using the agar dilution method. Ceftriaxone resistance determinants penA and penB were examined using sequencing. N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed for molecular epidemiology.Results: Among isolates, 0.2% were resistant to spectinomycin, 4.4% to ceftriaxone, 42.9% to tetracyclines (high-level resistance) and 99.8% to ciprofloxacin. Among 890 sequenced isolates, 16 (1.8%) possessed a penA mosaic allele; 4 of these isolates belonged to the MDR internationally spread NG-MAST genogroup G1407 (first description in China). Non-mosaic penA alleles with an A501T mutation and an A102D alteration in porB1b were statistically associated with decreased susceptibility/resistance to ceftriaxone. NG-MAST G10339, G1424 and G1053 were associated with decreased susceptibility/resistance to ceftriaxone.Conclusions: In China, ceftriaxone and spectinomycin can continue to be recommended for gonorrhoea treatment, with the possible exception of Hainan and Sichuan provinces where ceftriaxone resistance exceeded 5% and AMR surveillance needs to be strengthened. Molecular approaches including genotyping and AMR determinant analysis can be valuable to supplement and enhance conventional surveillance of gonococcal AMR in China.
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| 6. |
- Chen, Shao-Chun, et al.
(författare)
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Prevalence and Molecular Epidemiological Typing of Penicillinase-Producing Neisseria gonorrhoeae and Their bla(TEM-135) Gene Variants in Nanjing, China
- 2013
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Ingår i: Sexually Transmitted Diseases. - 0148-5717 .- 1537-4521. ; 40:11, s. 872-876
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study aimed to investigate the prevalence of penicillinase-producing Neisseria gonorrhoeae (PPNG) and their bla(TEM-135) gene variant in 2007 and 2012 in Nanjing, China. In addition, molecular epidemiological typing of all isolates was performed to elucidate the genetic relationships of the PPNG strains. Methods: A total of 199 and 77 N. gonorrhoeae isolates were collected at the National Center for STD Control in 2007 and 2012, respectively. Nitrocefin tests were performed to identify PPNG. Mismatch amplification mutation assay was used to identify bla(TEM-135). All isolates were genotyped using N. gonorrhoeae multiantigen sequence typing (NG-MAST), and additionally, porB-based phylogenetic analysis was performed for the PPNG isolates. Results: The total prevalence of PPNG isolates was 41% (114/276) and 58% (66/114) of these PPNG isolates possessed bla(TEM-135). In 2007, 45% (90/199) produced beta-lactamase, and of those PPNG, 58% (52/90) possessed bla(TEM-135). In 2012, 31% (24/77) were PPNG, and 58% (14/24) of those isolates contained bla(TEM-135). There were 162 NG-MAST STs among the 276 isolates, and 89 of those were novel STs. A strong association between specific NG-MAST STs and bla(TEM-135) was found, and the porB-based phylogenetic analysis showed a distant evolutionary relationship between isolates in 2007 and isolates in 2012. Conclusions: A high prevalence of PPNG and bla(TEM-135) was found in Nanjing, China. bla(TEM-135) might be a precursor in the evolution into an extended-spectrum beta-lactamase that can degrade ceftriaxone, which stresses the need to continuously monitor PPNG, bla(TEM-135), and additional evolving bla(TEM) gene variants.
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| 7. |
- Chen, X, et al.
(författare)
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Negative thermal quenching of below-bandgap photoluminescence in InPBi
- 2017
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports a temperature-dependent (10-280 K) photoluminescence (PL) study of below-bandgap electron-hole recombinations and anomalous negative thermal quenching of PL intensity in InP1- xBix (x = 0.019 and 0.023). Four PL features are well resolved by curve-fitting of the PL spectra, of which the energies exhibit different temperature dependence. The integral intensities of the two high-energy features diminish monotonically as temperature rises up, while those of the two low-energy features decrease below but increase anomalously above 180 K. A phenomenological model is established that the residual electrons in the final state of the PL transition transfer into nonradiative state via thermal hopping, and the thermal hopping produces in parallel holes in the final state and hence enhances the radiative recombination significantly. A reasonable interpretation of the PL processes in InPBi is achieved, and the activation energies of the PL quenching and thermal hopping are deduced. © 2017 Author(s).
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| 8. |
- Fan, Xiaoyu, et al.
(författare)
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Paper test strip for silver ions detection in drinking water samples based on combined fluorometric and colorimetric methods
- 2023
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Ingår i: Arabian Journal of Chemistry. - : Elsevier. - 1878-5352 .- 1878-5379. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a portable silver ion (Ag+) sensor was fabricated based on a dual signal output system using black phosphorus quantum dots (BPQDs) as probes. It is the first work for Ag+ detection using paper test strip based on BPQDs. The color change of BPQDs paper sensor for the determination of Ag+ was easily identified by naked eye. BPQDs were synthesized from bulk black phosphorus (BP) by mechanical exfoliation combined with a solvothermal method. BPQDs exhibited blue fluorescence with a quantum yield of 8.82 %. The fluorescence of BPQDs can be quenched by Ag+, and the absorbance of BPQDs is increased with increasing Ag+ concentration. The mechanism of the interaction between BPQDs and Ag+ involving fluorescence quenching and bonding was investigated by experimental and computational methods. The detection limit of Ag+ was 1.56 μg/mL and 0.19 μg/mL using fluorometry and colorimetry methods, respectively. A portable visual sensor based on paper test strip was constructed for Ag+ detection using the colorimetric approach. The strategy was employed to determine Ag+ successfully in drinking water samples. Therefore, the proposed portable Ag+ sensor can be potentially utilized for the lab-free analysis of drinking water and even dietary samples.
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| 9. |
- Gao, Yulan, et al.
(författare)
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Dynamic Social-Aware Peer Selection for Cooperative Relay Management With D2D Communications
- 2019
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Ingår i: IEEE Transactions on Communications. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0090-6778 .- 1558-0857. ; 67:5, s. 3124-3139
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the optimal dynamic social-aware peer selection with spectrum-power trading to maximize the average sum energy efficiency (EE) of cellular users (CUs) for uplink transmission for an orthogonal frequency division multiple access cellular network with device-to-device (D2D) communications. Different from the previous studies, which mostly focus on how to exploit social ties in human social networks to construct the permutation of all the feasible peers, we consider dynamic peer selection with social awareness-aided spectrum-power trading in D2D overlaying communications. Specifically, the amount of transmit power from the D2D transmitters to relay the CUs for uplink transmission is determined by their social trust levels. Likewise, the D2D transmitters can gain the corresponding amount of spectrum from the CUs for D2D pair link communications, which can be regarded as the compensation of the power consumption for relaying CUs. We formulate the dynamic peer selection problems with social awareness-aided spectrum-power trading in cooperative D2D communications into the infinite-horizon time-average renewal-reward problems subject to time average constraints on a collection of penalty processes. And the Lyapunov optimization concepts-based drift-plus-penalty algorithms are proposed to solve them. The simulation results demonstrate the effectiveness of the proposed dynamic peer selection algorithms. And further performance comparison indicates that the proposed dynamic peer selection algorithms not only maximize the average EE of CUs but also guarantee higher privacy protection.
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| 10. |
- Gao, Yulan, et al.
(författare)
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Game Theory-Based Anti-Jamming Strategies for Frequency Hopping Wireless Communications
- 2018
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Ingår i: IEEE Transactions on Wireless Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-1276 .- 1558-2248. ; 17:8, s. 5314-5326
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Tidskriftsartikel (refereegranskat)abstract
- In frequency hopping (FH) wireless communications, finding an effective transmission strategy to properly mitigate jamming has been recently considered as a critical issue, due to the inherent broadcast nature of wireless communications. Recently, game theory has been proposed as a powerful tool for dealing with the jamming problem, which can be considered as a player (jammer) playing against a user (transmitter). Different from existing results, in this paper, a bimatrix game framework is developed for modeling the interaction process between the transmitter and the jammer, and the sufficient and necessary conditions for Nash equilibrium (NE) strategy of the game are obtained under the linear constraints. Furthermore, the relationship between the NE solution and the global optimal solution of the corresponding quadratic programming is presented. In addition, a special analysis case is developed based on the continuous game framework in which each player has a continuum of strategies. Finally, we show that the performance can be improved based on our game theoretic framework, which is verified by numerical investigations.
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