| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
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.
|
|
| 2. |
- Han, Yini, et al.
(författare)
-
Optimization of land use pattern reduces surface runoff and sediment loss in a Hilly-Gully watershed at the Loess Plateau, China
- 2016
-
Ingår i: Forest Systems. - : Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA). - 2171-9845. ; 25:1, s. 45-54
-
Tidskriftsartikel (refereegranskat)abstract
- Aim of study: The aim is to find a way increasing gain yield and lessen area of farmland, and then increasing vegetation cover, improving environment and alleviating soil erosion.Area of study: The Hilly-Gully region at the loess plateau of China.Material and methods: In this study, an adjusted and optimized land use pattern was developed in Luoyugou watershed in the Yellow River valley based on the gradient distribution of land use types, and its effect on water and sediment transport was simulated using the SWAT model and GIS, with remote sensing images, land use maps and hydrologic data.Main results: The results indicate: average simulated runoff and sediment for the period 1986-2000 under conditions of the three land use pattern (2011, 2008 and optimized land use) reduced by 0.002-0.013 m3/s (2.7-17.6%) and 0.66 million tons, respectively. The runoff and sediment data obtained were compared with observed data from 2008, which showed that runoff and sediment production would be reduced by 467625 m3 and 22754 tons, respectively.Research highlights: The adjustment of the land use pattern in comprehensive consideration of vegetation and geography have a positive effect on water and sediment transport which will be important for decision making and water resources management, and provides a reference for future environmental management and ecological construction in the loess plateau Hilly-Gully region.
|
|
| 3. |
- Zhang, Xilin, et al.
(författare)
-
Regulation of CO oxidation with Pd additives on Nb2CO2 MXene
- 2021
-
Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 46:12, s. 8477-8485
-
Tidskriftsartikel (refereegranskat)abstract
- Catalytic properties of the 2D material Nb2CO2 (MXene) with a surface oxygen vacancy and a supported single Pd atom in it (Pd/O-V-Nb2CO2) is explored using DFT calculations. It is found that the single Pd atom can be stably anchored in the oxygen vacancy and out of three mechanisms for carbon monoxide oxidation were studied for our model catalyst and one of them shows promising features, namely CO oxidation via a tri-molecular Eley-Rideal (TER) mechanism which has a small activation barrier of 0.42 eV. This result may provide some guidance for the selection of anode materials with high CO-tolerance and high efficiency in removing CO from H-2 for PEMFCs.
|
|
| 4. |
- Zhang, Xilin, et al.
(författare)
-
Tuning the ORR activity of Pt-based Ti(2)CO(2)MXenes by varying the atomic cluster size and doping with metals
- 2020
-
Ingår i: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 12:23, s. 12497-12507
-
Tidskriftsartikel (refereegranskat)abstract
- The rational design of ideal catalysts for the oxygen reduction reaction (ORR) is of great significance for solving the electrocatalytic potential problems in proton exchange membrane fuel cells (PEMFCs). Pt-n(n= 1-4) and Pt3Au alloy subnanoclusters supported on a defective Ti(2)CO(2)monolayer with oxygen vacancies (denoted as v-Ti2CO2) are simulated by using density functional theory to investigate their ORR performance. The geometries, energetics, and electronic properties of the different systems are analyzed. It is found that the supported Pt3Au alloy subnanocluster possesses the best ORR activity. The underlying mechanisms of the improved ORR activity originates from the moderate hybridization between the O 2p and the 5d orbitals of Au and Pt according to the density of states analysis. Our study suggests a facile route for designing low-cost MXene-based electrocatalysts by alloying transition metals with Pt catalysts, which may stimulate realization of suitable alternative catalysts for ORR catalysis.
|
|
| 5. |
- Cheng, Cheng, et al.
(författare)
-
Identification of High-Performance Single-Atom MXenes Catalysts for Low-Temperature CO Oxidation
- 2019
-
Ingår i: Advanced Theory and Simulations. - : WILEY-V C H VERLAG GMBH. - 2513-0390. ; 2:8
-
Tidskriftsartikel (refereegranskat)abstract
- On the basis of first-principles calculations, Fe, Co, Ni, Cu, Zn, Ru, Rh, Ag, Ir, Pt, and Au decorated Mo2CO2-delta monolayers are investigated as potential single-atom catalyst (SAC) candidates for low-temperature CO oxidation reaction. From a first screening based on intuitive criteria concerning metal sintering, CO poisoning, and O-2 adsorption strength, the Zn/Mo2CO2-delta system is selected for further scrutiny by means of reactivity calculations for different CO concentrations. A lower barrier is found for Eley-Rideal reaction mechanism than for the Langmuir-Hinshelwood mechanism. The low Eley-Rideal barrier (0.15 eV) is attributed to the fact that the Zn atom weakens the O-O bond considerably and the electrophilic attack of CO weakens it further. The main conclusion is that this system is a promising low-temperature SAC candidate with a lower energy barrier for CO oxidation than noble metal and other 2D SAC systems investigated.
|
|
| 6. |
- Johnson, Calvin W., et al.
(författare)
-
White paper: From bound states to the continuum
- 2020
-
Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:12
-
Forskningsöversikt (refereegranskat)abstract
- This white paper reports on the discussions of the 2018 Facility for Rare Isotope Beams Theory Alliance (FRIB-TA) topical program ‘From bound states to the continuum: Connecting bound state calculations with scattering and reaction theory’. One of the biggest and most important frontiers in nuclear theory today is to construct better and stronger bridges between bound state calculations and calculations in the continuum, especially scattering and reaction theory, as well as teasing out the influence of the continuum on states near threshold. This is particularly challenging as many-body structure calculations typically use a bound state basis, while reaction calculations more commonly utilize few-body continuum approaches. The many-body bound state and few-body continuum methods use different language and emphasize different properties. To build better foundations for these bridges, we present an overview of several bound state and continuum methods and, where possible, point to current and possible future connections.
|
|
| 7. |
- Tews, Ingo, et al.
(författare)
-
Nuclear Forces for Precision Nuclear Physics: A Collection of Perspectives
- 2022
-
Ingår i: Few-Body Systems. - : Springer Science and Business Media LLC. - 1432-5411 .- 0177-7963. ; 63:4
-
Tidskriftsartikel (refereegranskat)abstract
- This is a collection of perspective pieces contributed by the participants of the Institute for Nuclear Theory's Program on Nuclear Physics for Precision Nuclear Physics which was held virtually from April 19 to May 7, 2021. The collection represents the reflections of a vibrant and engaged community of researchers on the status of theoretical research in low-energy nuclear physics, the challenges ahead, and new ideas and strategies to make progress in nuclear structure and reaction physics, effective field theory, lattice QCD, quantum information, and quantum computing. The contributed pieces solely reflect the perspectives of the respective authors and do not represent the viewpoints of the Institute for Nuclear theory or the organizers of the program.
|
|
| 8. |
- Zhang, Xilin, et al.
(författare)
-
A New Mars-van Krevelen Mechanism for CO Oxidation on a Ti-Decorated MXene
- 2023
-
Ingår i: Advanced Materials Interfaces. - : Wiley-Blackwell. - 2196-7350. ; 10:29
-
Tidskriftsartikel (refereegranskat)abstract
- First-principles computations are performed to investigate the catalytic oxidation of CO on a Ti-decorated Cr2TiC2O2 MXene monolayer, through comprehensive analysis of charge transfer, electronic density of states, and charge density difference of the interacting systems. By comparing the reaction energy barriers, it is found that, rather than the traditional Langmuir-Hinshelwood, Eley-Rideal, and Mars-van Krevelen (MvK) mechanisms, the CO oxidation favours a new variant of the MvK mechanism, in which the anchored Ti atom activates the surface oxygen to spill over from the substrate and take part in the CO oxidation. This work highlights the importance of activating the surface oxygen atoms of MXene by foreign metal atoms to improve the catalytic activity, and suggests that further studies into the new MvK mechanism for CO oxidation may prove worthwhile.
|
|
| 9. |
- Zhao, Yuli, et al.
(författare)
-
Relationships between individual small tree canopy structure and rainfall interception
- 2014
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Among the layers of a plant community, the canopy has the most important hydrological function in water circulation. Understanding the canopy’s inner structure and its relationship to water transport is fundamental for the functional mechanisms of the vegetation canopy. Using an artificial rainfall simulator to supply three levels of rainfall intensity, the interception of rainfall by the canopy was measured to study the characteristics of individual trees using different rainfall conditions and structural parameters. The study was done for four small native tree species: Platycladus orientalis, Pinus tabulaeformis, Quercus variabilis and Acer elegantulum. The resulting variations in the process of canopy interception could be divided into periods of increasing, slightly decreasing in some species, and stable levels of interception. In addition, duration of the initial period of increasing interception shortened as rainfall intensity increased. When rainfall was less intense, the percentage of gross rainfall intercepted by P. orientalis, P. tabulaeformis and A. elegantulum canopy layers was in the order mid > upper > lower canopy, while for Q. variabilis the sequence was upper > mid > lower canopy. These sequences indicate that canopy superstructure was more important than canopy substructure regarding the ability of the canopy to intercept precipitation and thus prevent soil erosion. Furthermore, it was found that exponential and logarithmic functions could be used to describe the relationship between interception of coniferous and deciduous species, respectively, and their own canopy body types. This study provided preliminary criteria for determining the optimal crown type for rainfall interception.
|
|
