| 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. |
- Bai, Yang, et al.
(författare)
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Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells
- 2023
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Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- With the power conversion efficiency of binary polymer solar cells dramatically improved, the thermal stability of the small-molecule acceptors raised the main concerns on the device operating stability. Here, to address this issue, thiophene-dicarboxylate spacer tethered small-molecule acceptors are designed, and their molecular geometries are further regulated via the thiophene-core isomerism engineering, affording dimeric TDY-alpha with a 2, 5-substitution and TDY-beta with 3, 4-substitution on the core. It shows that TDY-alpha processes a higher glass transition temperature, better crystallinity relative to its individual small-molecule acceptor segment and isomeric counterpart of TDY-beta, and amore stablemorphology with the polymer donor. As a result, the TDY-alpha based device delivers a higher device efficiency of 18.1%, and most important, achieves an extrapolated lifetime of about 35000 hours that retaining 80% of their initial efficiency. Our result suggests that with proper geometry design, the tethered small-molecule acceptors can achieve both high device efficiency and operating stability.
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| 3. |
- Zhang, Yuanyuan, et al.
(författare)
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Early-life exposure to PM2.5 constituents and childhood asthma and wheezing : Findings from China, Children, Homes, Health study
- 2022
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- Background: Emerging evidence suggests that early-life (in-utero and first-year since birth) exposure to ambient PM2.5 is a risk factor for asthma onset and exacerbation among children, while the hazards caused by PM2.5 compositions remain largely unknown.Objective: To examine potential associations of early-life exposures to PM2.5 mass and its major chemical constituents with childhood asthma and wheezing.Methods: By conducting the Phase II of the China, Children, Homes, Health study, we investigated 30,325 preschool children aged 3-6 years during 2019-2020 in mainland China. Early-life exposure to PM2.5 mass and its constituents (i.e., black carbon [BC], organic matter [OM], nitrate, ammonium, sulfate) were calculated based on monthly estimates at a 1 km x 1 km resolution from satellite-based models. We adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM2.5 constituents on childhood asthma/wheezing.Results: The average PM2.5 concentrations during in-utero and the first year since birth were 64.7 +/- 10.6 and 61.8 +/- 10.5 mu g/m(3), respectively. Early-life exposures to a mixture of major PM2 center dot 5 constituents were significantly associated with increased risks of asthma and wheezing, while no evident compositions-wheezing associations were found in the first year. Each quintile increases in all five PM2.5 components exposures in utero was accordingly associated with an odds ratio of 1.18 [95% confidence interval: 1.07-1.29] for asthma and 1.08 [1.01-1.16] for wheezing. BC, OM and SO42- contributed more to risks of asthma and wheezing than the other PM2.5 constituents during early life, wherein the effects of BC were only observed during pregnancy. Sex subgroup analyses suggested stronger associations among girls of first-year exposures to PM2.5 components with childhood asthma.Conclusion: Early-life exposures to ambient PM2.5, particularly compositions of BC, OM and SO42-, are associated with an increased risk of childhood asthma.
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| 4. |
- Zhang, Wei, et al.
(författare)
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Organic Salts as p-Type Dopants for Efficient LiTFSI-Free Perovskite Solar Cells
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:30, s. 33751-33758
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Tidskriftsartikel (refereegranskat)abstract
- Despite the ubiquity and importance of organic hole-transport materials in photovoltaic devices, their intrinsic low conductivity remains a drawback. Thus, chemical doping is an indispensable solution to this drawback and is essentially always required. The most widely used p-type dopant, FK209, is a cobalt coordination complex. By reducing Co(III) to Co(II), Spiro-OMeTAD becomes partially oxidized, and the film conductivity is initially increased. In order to further increase the conductivity, the hygroscopic co-dopant LiTFSI is typically needed. However, lithium salts are normally quite hygroscopic, and thus, water absorption has been suggested as a significant reason for perovskite degradation and therefore limited device stability. In this work, we report a LiTFSI-free doping process by applying organic salts in relatively high amounts. The film conductivity and morphology have been studied at different doping amounts. The resulting solar cell devices show comparable power conversion efficiencies to those based on conventional LiTFSI-doped Spiro-OMeTAD but show considerably better long-term device stability in an ambient atmosphere.
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| 5. |
- Lensink, Marc F., et al.
(författare)
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Impact of AlphaFold on structure prediction of protein complexes: The CASP15-CAPRI experiment
- 2023
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Ingår i: Proteins. - : WILEY. - 0887-3585 .- 1097-0134.
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Tidskriftsartikel (refereegranskat)abstract
- We present the results for CAPRI Round 54, the 5th joint CASP-CAPRI protein assembly prediction challenge. The Round offered 37 targets, including 14 homodimers, 3 homo-trimers, 13 heterodimers including 3 antibody-antigen complexes, and 7 large assemblies. On average similar to 70 CASP and CAPRI predictor groups, including more than 20 automatics servers, submitted models for each target. A total of 21 941 models submitted by these groups and by 15 CAPRI scorer groups were evaluated using the CAPRI model quality measures and the DockQ score consolidating these measures. The prediction performance was quantified by a weighted score based on the number of models of acceptable quality or higher submitted by each group among their five best models. Results show substantial progress achieved across a significant fraction of the 60+ participating groups. High-quality models were produced for about 40% of the targets compared to 8% two years earlier. This remarkable improvement is due to the wide use of the AlphaFold2 and AlphaFold2-Multimer software and the confidence metrics they provide. Notably, expanded sampling of candidate solutions by manipulating these deep learning inference engines, enriching multiple sequence alignments, or integration of advanced modeling tools, enabled top performing groups to exceed the performance of a standard AlphaFold2-Multimer version used as a yard stick. This notwithstanding, performance remained poor for complexes with antibodies and nanobodies, where evolutionary relationships between the binding partners are lacking, and for complexes featuring conformational flexibility, clearly indicating that the prediction of protein complexes remains a challenging problem.
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| 6. |
- Liu, Anbu, et al.
(författare)
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DDR1/2 enhance KIT activation and imatinib resistance of primary and secondary KIT mutants in gastrointestinal stromal tumors
- 2024
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Ingår i: Molecular Carcinogenesis. - 0899-1987. ; 63:1, s. 75-93
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Tidskriftsartikel (refereegranskat)abstract
- Gastrointestinal stromal tumors (GISTs) are predominantly initiated by KIT mutations. In this study, we observed that discoidin domain receptors 1 and 2 (DDR1 and DDR2) exhibited high expression in GISTs, were associated with KIT, and enhanced the activation of both wild-type KIT and primary KIT mutants. Inhibition of DDR1/2 led to a reduction in the activation of KIT and its downstream signaling molecules, ultimately impairing GIST cell survival and proliferation in vitro. Consequently, treatment of mice carrying germline KIT/V558A mutation with DDR1/2 inhibitor significantly impeded tumor growth, and the combined use of DDR1/2 inhibitor and imatinib, the first-line targeted therapeutic agent for GISTs, markedly enhanced tumor growth suppression. In addition, DDR1/2 inhibition resulted in decreased KIT expression, while KIT inhibition led to upregulation of DDR1/2 expression in GISTs. The presence of DDR1/2 also decreased the sensitivity of wild-type KIT or primary KIT mutants to imatinib, indicating a possible role for DDR1/2 in promoting GIST survival during KIT-targeted therapy. The development of drug-resistant secondary KIT mutations is a primary factor contributing to GIST recurrence following targeted therapy. Similar to primary KIT mutants, DDR1/2 can associate with and enhance the activation of secondary KIT mutants, further diminishing their sensitivity to imatinib. In summary, our data demonstrate that DDR1/2 contribute to KIT activation in GISTs and strengthen resistance to imatinib for both primary and secondary KIT mutants, providing a rationale for further exploration of DDR1/2 targeting in GIST treatment.
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| 7. |
- Liu, Yi, et al.
(författare)
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Porous, robust, thermally stable, and flame retardant nanocellulose/polyimide separators for safe lithium-ion batteries
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 11:43, s. 23360-23369
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Tidskriftsartikel (refereegranskat)abstract
- The safety of lithium-ion batteries (LIBs) is paramount for all users. One effective way to improve safety is incorporating heat-resistant polyimide (PI) separators, which can increase the thermal stability of batteries and minimize the risk of thermal runaway. However, preparing PI separators with both an ideal pore structure and adequate mechanical properties remains as a challenge. Here, we introduced decabromodiphenyl ethane (DBDPE) and cellulose nanofibers (CNFs) into PI and produced a hybrid separator with an outstanding pore structure and excellent mechanical properties. Aided with DBDPE, the separators attain a well-defined and uniform pore size (20 nm), while demonstrating high porosities (78%) through phase inversion processes. Owing to the addition of CNFs, the mechanical properties of the separators were significantly improved, with a tensile strength of 25.4 MPa and an elastic modulus of 550.1 MPa. Moreover, the separators demonstrate high ion conductivity (0.45 mS cm-1), excellent thermal-dimensional stability (up to 200 degrees C), remarkable flame retardancy, and outstanding electrolyte wettability. At room temperature, the batteries with the separators demonstrate comparable performance with those of polypropylene (PP) separators. However, when subjected to thermal shock treatments, the batteries with the separators outperform those with PP, showcasing their superior performance. The work introduces a novel strategy for designing high-performance separators, thereby paving the way for advancements in the fabrication of LIBs with enhanced safety features. A porous, robust, and thermally stable hybrid separator was developed to solve the dilemma between desired pore structures and mechanical properties in polyimide separators by introducing decabromodiphenyl ethane and cellulose nanofibers.
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| 8. |
- Wang, Linqin, et al.
(författare)
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A crosslinked polymer as dopant-free hole-transport material for efficient n-i-p type perovskite solar cells
- 2021
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Ingår i: Journal of Energy Chemistry. - : Elsevier BV. - 2095-4956 .- 2096-885X. ; 55, s. 211-218
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Tidskriftsartikel (refereegranskat)abstract
- A new crosslinked polymer, called P65, with appropriate photo-electrochemical, opto-electronic, and thermal properties, has been designed and synthesized as an efficient, dopant-free, hole-transport material (HTM) for n-i-p type planar perovskite solar cells (PSCs). P65 is obtained from a low-cost and easily synthesized spiro[fluorene-9,9′-xanthene]-3′,6′-diol (SFX-OH)-based monomer X65 through a free-radical polymerization reaction. The combination of a three-dimensional (3D) SFX core unit, hole-transport methoxydiphenylamine group, and crosslinked polyvinyl network provides P65 with good solubility and excellent film-forming properties. By employing P65 as a dopant-free hole-transport layer in conventional n-i-p type PSCs, a power conversion efficiency (PCE) of up to 17.7% is achieved. To the best of our knowledge, this is the first time a 3D, crosslinked, polymeric dopant-free HTM has been reported for use in conventional n-i-p type PSCs. This study provides a new strategy for the future development of a 3D crosslinked polymeric dopant-free HTM with a simple synthetic route and low-cost for commercial, large-scale applications in future PSCs.
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| 9. |
- Yang, Xia, et al.
(författare)
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Integrated assessment of indoor and outdoor ventilation in street canyons with naturally-ventilated buildings by various ventilation indexes
- 2020
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 169
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Tidskriftsartikel (refereegranskat)abstract
- The integrated assessments of indoor and outdoor ventilation are still rare so far. As a novelty, this paper aims to quantify the influence of street aspect ratios (building height/street width, H/W = 0.5–5) and window sizes (1 m × 1 m, 1.5 m × 1.5 m) on indoor-outdoor ventilation in two-dimensional streets with single-sided naturally-ventilated buildings. Numerical simulations with RNG k-ε model are validated against experimental data and the grid independence are tested as well. Air change rates per hour (ACH, h−1) are adopted for assessing indoor-outdoor ventilation by mean flows (ACHmean) and turbulent fluctuations (ACHturb) respectively. Age of air(τ), purging flow rate (PFR) and its corresponding ACHPFR are used to evaluate overall ventilation capacities.Shallower streets experience better indoor-outdoor ventilation. Outdoor ACHPFR drop from 14.69 to 17.55 h−1 to 3.96–3.97 h−1 as H/W rises from 0.5 to 3. In extremely deep canyon (H/W = 5), two-counter-rotating vortices produce much smaller velocity at low-level regions (U/Uref~10−3-10−5), resulting in small ACHPFR for outdoor (~0.76–0.91 h−1) and indoor in 1–13th floors (~0.03–0.61 h−1). When H/W = 0.5–1, leeward 5–6th floors experience smaller ACHPFR(e.g.~1.13–1.40 h−1 as H/W = 1) than the other floors (e.g. ~1.54–9.52 h−1 as H/W = 1). Particularly, as H/W = 2–3, leeward-side indoor ACHPFR in the middle floors (except the first and top two floors) are nearly constants (~1.02–1.69 h−1) and much smaller than windward-side ACHPFR(~1.41–4.35 h−1) which increase toward upper floors. Besides, the smaller window size reduces indoor ACHPFR by 19.38%~88.28%, but hardly influences outdoor ventilation. Moreover, both outdoor and indoor ACHPFR are greater than ACHmean but smaller than ACHmean + ACHturb. Although further investigations are still required, this paper provides an insight and scientific foundation on integrated indoor-outdoor ventilation evaluation with various effective ventilation indexes.
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| 10. |
- Zhang, Xin, et al.
(författare)
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Minimizing the Interface-Driven Losses in Inverted Perovskite Solar Cells and Modules
- 2023
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; , s. 2532-2542
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Tidskriftsartikel (refereegranskat)abstract
- The inverted p-i-n perovskite solar cells hold high promise for scale-up toward commercialization. However, the interfaces between the perovskite and the charge transport layers contribute to major power conversion efficiency (PCE) loss and instability. Here, we use a single material of 2-thiopheneethylammonium chloride (TEACl) to molecularly engineer both the interface between the perovskite and fullerene-C60 electron transport layer and the buried interface between the perovskite and NiOx-based hole transport layer. The dual interface modification results in optimized band alignment, suppressed nonradiative recombination, and improved interfacial contact. A PCE of 24.3% is demonstrated, with open-circuit voltage (Voc) and fill factor (FF) of 1.17 V and 84.6%, respectively. The unencapsulated device retains >97.0% of the initial performance after 1000 h of maximum power point tracking under illumination. Moreover, a PCE of 22.6% and a remarkable FF of 82.4% are obtained for a mini-module with an active area of 3.63 cm2.
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