| 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. |
- Campbell, PJ, et al.
(författare)
-
Pan-cancer analysis of whole genomes
- 2020
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
-
Tidskriftsartikel (refereegranskat)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
|
|
| 3. |
- Liang, Xifeng, et al.
(författare)
-
On the aerodynamic loads when a high speed train passes under an overhead bridge
- 2020
-
Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 202
-
Tidskriftsartikel (refereegranskat)abstract
- The aerodynamic loads on the overhead bridge bottom surface induced by train passage are reported in this paper. Both moving model test and numerical simulation approaches at the 1:20 scale are used. The numerical work is validated through both mesh independence tests and comparison with experimental data. Typical pressure variation curves are plotted and compared with previous studies. The peak pressure values’ dependence on the Reynolds number is considered through four sets of experiments with different train running speeds. The peak pressure coefficient distribution law for the bridge bottom surface is presented. Differences in the pressure distribution in different bridge bottom areas are explained based on more detailed flow field information. The influence of the bridge height on the aerodynamic load magnitude and time interval is presented. Moreover, the application of the CEN Standard to practical engineering issues is discussed.
|
|
| 4. |
- Song, Kai, 1988-, et al.
(författare)
-
Improve the roles of nature reserves in conservation of endangered pheasant in a highly urbanized region
- 2020
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Nature reserves play an extraordinarily important role in conserving animal populations and their habitats. However, landscape change and unreasonable zoning designations often render these protected areas inadequate. Therefore, regular evaluation of the efficacy of protected lands is critical for maintaining and improving management strategies. Using species distribution models and GAP analysis, we assessed the changes in suitable habitat for the Brown Eared-pheasant (Crossoptilon mantchuricum) in two Chinese nature reserves between 1995 and 2013. Our results showed that the habitat suitability of Brown Eared-pheasant has changed dramatically during this period, and fragmentation analyses showed an increase in concentration area and decrease in patch area. In particular, our findings show that the national nature reserves need to adjust their ranges to ensure the conservation of this flagship species. Our study further provides a new viewpoint for evaluating the efficacy of protected lands, particularly in highly urbanized regions where conservation goals must be balanced with changing landscapes.
|
|
| 5. |
- Awad, Raed, et al.
(författare)
-
Emerging Per- and Polyfluoroalkyl Substances (PFAS) in Human Milk from Sweden and China
- 2020
-
Ingår i: Environmental Science. - 2050-7887 .- 2050-7895. ; 19:22
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Twenty per- and polyfluoroalkyl substances (PFAS) were determined in human milk from residents of three Chinese cities (Shanghai, Jiaxing, and Shaoxing), sampled between 2010 and 2016. These data were compared to a combination of new and previously reported PFAS concentrations in human milk from Stockholm, Sweden, collected in 2016. Across the three Chinese cities, perfluorooctanoate (PFOA; sum isomers), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS; trade name F53-B), and perfluorooctane sulfonate (PFOS; sum isomers) occurred at the highest concentrations among all PFAS (up to 411, 976, and 321 pg/mL, respectively), while in Stockholm, PFOA and PFOS were dominant (up to 89 and 72 pg/mL, respectively). 3H-perfluoro-3-[(3-methoxy-propoxy) propanoic acid (ADONA) was intermittently detected but at concentrations below the method quantification limit (i.e. <10 pg/mL) in Chinese samples, and was non-detectable in Swedish milk. The extremely high concentrations of F53-B in Chinese milk suggest that human exposure assessments focused only on legacy substances may severely underestimate overall PFAS exposure in breastfeeding infants.
|
|
| 6. |
- Cai, Bin, et al.
(författare)
-
Unveiling the light soaking effects of the CsPbI3 perovskite solar cells
- 2020
-
Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 472
-
Tidskriftsartikel (refereegranskat)abstract
- Pure inorganic perovskite of CsPbI3 attracts great attentions due to its excellent thermal stability and more suitable bandgap for tandem solar cells. The power conversion efficiency (PCE) of CsPbI3 perovskite solar cells has swiftly increased to 19.03%. However, extensive researches on the material property and photovoltaic characterization are rather rare in the literatures. In this study, a remarkable light soaking effect is found in the CsPbI3 based perovskite solar cells as the PCE increases from 10.8% to 18.3% after 180 s soaking under AM 1.5G sunlight. Mechanisms behind this reproducible soaking effect have also been studied. It reveals that the depressed dark current caused by a stronger built-in field and the decreased defects density passivated by the photogenerated electrons result in the enhanced PCE after light soaking. Moreover, we carefully characterize that the supposed "HPbI3" should be "DMAPbI(3)" synthesized through anti-solvent vapor recrystallisation method.
|
|
| 7. |
- Chen, Wei, et al.
(författare)
-
In situ Grazing-Incidence Small-Angle X-ray Scattering Observation of Gold Sputter Deposition on a PbS Quantum Dot Solid
- 2020
-
Ingår i: ACS Applied Materials and Interfaces. - : NLM (Medline). - 1944-8244 .- 1944-8252. ; 12:41, s. 46942-46952
-
Tidskriftsartikel (refereegranskat)abstract
- For PbS quantum dot (QD)-based optoelectronic devices, gold is the most frequently used electrode material. In most device architectures, gold is in direct contact with the QD solid. To better understand the formation of the interface between gold and a close-packed QD layer at an early stage, in situ grazing-incidence small-angle X-ray scattering is used to observe the gold sputter deposition on a 1,2-ethanedithiol (EDT)-treated PbS QD solid. In the kinetics of gold layer growth, the forming and merging of small gold clusters (radius less than 1.6 nm) are observed at the early stages. The thereby formed medium gold clusters (radius between 1.9-2.4 nm) are influenced by the QDs' templating effect. Furthermore, simulations suggest that the medium gold clusters grow preferably along the QDs' boundaries rather than as a top coating of the QDs. When the thickness of the sputtered gold layer reaches 6.25 nm, larger gold clusters with a radius of 5.3 nm form. Simultaneously, a percolation layer with a thickness of 2.5 nm is established underneath the gold clusters. This fundamental understanding of the QD-gold interface formation will help to control the implementation of sputtered gold electrodes on close-packed QD solids in device manufacturing processes.
|
|
| 8. |
- Cichocka, Magdalena Ola, et al.
(författare)
-
A Porphyrinic Zirconium Metal-Organic Framework for Oxygen Reduction Reaction : Tailoring the Spacing between Active-Sites through Chain-Based Inorganic Building Units
- 2020
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:36, s. 15386-15395
-
Tidskriftsartikel (refereegranskat)abstract
- The oxygen reduction reaction (ORR) is central in carbon-neutral energy devices. While platinum group materials have shown high activities for ORR, their practical uses are hampered by concerns over deactivation, slow kinetics, exorbitant cost, and scarce nature reserve. The low cost yet high tunability of metal-organic frameworks (MOFs) provide a unique platform for tailoring their characteristic properties as new electrocatalysts. Herein, we report a new concept of design and present stable Zr-chain-based MOFs as efficient electrocatalysts for ORR. The strategy is based on using Zr-chains to promote high chemical and redox stability and, more importantly, tailor the immobilization and packing of redox active-sites at a density that is ideal to improve the reaction kinetics. The obtained new electrocatalyst, PCN-226, thereby shows high ORR activity. We further demonstrate PCN-226 as a promising electrode material for practical applications in rechargeable Zn-air batteries, with a high peak power density of 133 mW cm(-2). Being one of the very few electrocatalytic MOFs for ORR, this work provides a new concept by designing chain-based structures to enrich the diversity of efficient electrocatalysts and MOFs.
|
|
| 9. |
- Liang, Lin, et al.
(författare)
-
Non-Interpenetrated Single-Crystal Covalent Organic Frameworks
- 2020
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:41, s. 17991-17995
-
Tidskriftsartikel (refereegranskat)abstract
- Growth of covalent organic frameworks (COFs) as single crystals is extremely challenging. Inaccessibility of open-structured single-crystal COFs prevents the exploration of structure-oriented applications. Herein we report for the first time a non-interpenetrated single-crystal COF, LZU-306, which possesses the open structure constructed exclusively via covalent assembly. With a high void volume of 80 %, LZU-306 was applied to investigate the intrinsic dynamics of reticulated tetraphenylethylene (TPE) as the individual aggregation-induced-emission moiety. Solid-state(2)H NMR investigation has determined that the rotation of benzene rings in TPE, being the freest among the reported cases, is as fast as 1.0x10(4) Hz at 203 K to 1.5x10(7) Hz at 293 K. This research not only explores a new paradigm for single-crystal growth of open frameworks, but also provides a unique matrix-isolation platform to reticulate functional moieties into a well-defined and isolated state.
|
|
| 10. |
|
|
