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| 5. |
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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 6. |
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| 7. |
- Schuettpelz, Eric, et al.
(författare)
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A community-derived classification for extant lycophytes and ferns
- 2016
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Ingår i: Journal of Systematics and Evolution. - : Wiley. - 1674-4918 .- 1759-6831. ; 54:6, s. 563-603
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Tidskriftsartikel (refereegranskat)abstract
- Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community-based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.
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| 8. |
- Stanaway, Jeffrey D., et al.
(författare)
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Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1923-1994
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Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk-outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk-outcome pairs, and new data on risk exposure levels and risk- outcome associations. Methods We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
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| 9. |
- Zhang, Liangdong, et al.
(författare)
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Bright Free Exciton Electroluminescence from Mn-Doped Two-Dimensional Layered Perovskites
- 2019
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Ingår i: The Journal of Physical Chemistry Letters. - : AMER CHEMICAL SOC. - 1948-7185. ; 10:11, s. 3171-3175
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) perovskites incorporating hydrophobic organic spacer cations show improved film stability and morphology compared to their three-dimensional (3D) counterparts. However, 2D perovskites usually exhibit low photoluminescence quantum efficiency (PLQE) owing to strong exciton-phonon interaction at room temperature, which limits their efficiency in light-emitting diodes (LEDs). Here, we demonstrate that the device performance of 2D perovskite LEDs can be significantly enhanced by doping Mn(2+)in (benzimidazolium)(2)PbI4 2D perovskite films to suppress the exciton-phonon interaction. The distorted [PbI6](4-) octahedra by Mn-doping and the rigid benzimidazolium (BIZ) ring without branched chains in the 2D perovskite structure lead to improved crystallinity and rigidity of the perovskites, resulting in suppressed phonon-exciton interaction and enhanced PLQE. On the basis of this strategy, for the first time, we report yellow electroluminescence from free excitons in 2D (n = 1) perovskites with a maximum brightness of 225 cd m(-2) and a peak EQE of 0.045%.
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| 10. |
- Feng, Ruizhi, et al.
(författare)
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Mutations in TUBB8 and Human Oocyte Meiotic Arrest.
- 2016
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Ingår i: The New England journal of medicine. - 1533-4406. ; 374:3, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- Background Human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. Methods We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, early embryos, sperm cells, and several somatic tissues by means of a quantitative reverse-transcriptase-polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. Results We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. Conclusions TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility. (Funded by the National Basic Research Program of China and others.).
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| 11. |
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| 12. |
- Miao, Fengjuan, et al.
(författare)
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Inkjet printing of electrochemically-exfoliated graphene nano-platelets
- 2016
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Ingår i: Synthetic metals. - : Elsevier. - 0379-6779 .- 1879-3290. ; 220, s. 318-322
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we report on a facile method of inkjet printing of graphene nano-platelets (GNPs). The GNPs are exfoliated from graphite by means of an electrochemical process in an inorganic salt based electrolyte. The electrochemically exfoliated GNPs with oxygen-bearing functional groups exhibit spectroscopic features similar to those of reduced graphene oxides. As a result, ink formulation with such GNPs for inkjet printing readily accomplishes without using stabilizer and various conductive objects are easily fabricated on different substrates by inkjet printing. The as-printed films of the electrochemically exfoliated GNPs deliver an electrical conductivity of 44 S/m, a typical value for as-printed pristine GNP films in the literature. A simple thermal treatment results in an improved DC conductivity by two orders of magnitude to ~2.5 × 103 S/m.
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| 13. |
- Tao, Bairui, et al.
(författare)
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Three-dimensional graphene nanosheets supported by NiO/Si-MCP as electrode materials for high-performance supercapacitors
- 2017
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Ingår i: Ionics (Kiel). - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 23:8, s. 2185-2191
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional (3D) graphene/NiO/Si-microchannel (MCP) composite electrode is synthesized by the conventional microelectronic machining process and electrochemical exfoliation technology for electrochemical capacitors. SEM, AFM, and Raman scattering are used to investigate the morphology and structure, and electrochemical characterization reveals that the 3D graphene/NiO/Si-MCP has a high specific capacitance of 833 Fg-1 at a current density of 5 Ag-1 in 6 mol L-1 KOH. Moreover, good cycling performance with 92% capacitance retention after 1000 cycles is observed indicating the novel electrode has large potential in high-performance supercapacitors.
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| 14. |
- Wei, Jiang, et al.
(författare)
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17β-estradiol regulates the expression of apolipoprotein M through estrogen receptor α-specific binding motif in its promoter
- 2017
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Ingår i: Lipids in Health and Disease. - : Springer Science and Business Media LLC. - 1476-511X. ; 16:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Background: We have previously demonstrated that estrogen could significantly enhance expression of apolipoprotein M (apoM), whereas the molecular basis of its mechanism is not fully elucidated yet. To further investigate the mechanism behind the estrogen induced up-regulation of apoM expression. Results: Our results demonstrated either free 17β-estradiol (E2) or membrane-impermeable bovine serum albumin-conjugated E2 (E2-BSA) could modulate human apoM gene expression via the estrogen receptor alpha (ER-α) pathway in the HepG2 cells. Moreover, experiments with the luciferase activity analysis of truncated apoM promoters could demonstrate that a regulatory region (from-1580 to −1575 bp (−GGTCA-)) upstream of the transcriptional start site of apoM gene was essential for the basal transcriptional activity that regulated by the ER-α. With the applications of an electrophoresis mobility shift assay and a chromatin immunoprecipitation assay, we could successfully identify a specific ER-α binding element in the apoM promoter region. Conculsion: In summary, the present study indicates that 17β-estradiol induced up-regulation of apoM in HepG2 cells is through an ER-α-dependent pathway involving ER-α binding element in the promoter of the apoM gene.
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| 15. |
- Wuttke, Matthias, et al.
(författare)
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A catalog of genetic loci associated with kidney function from analyses of a million individuals
- 2019
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Ingår i: Nature Genetics. - : NATURE PUBLISHING GROUP. - 1061-4036 .- 1546-1718. ; 51:6, s. 957-972
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Tidskriftsartikel (refereegranskat)abstract
- Chronic kidney disease (CKD) is responsible for a public health burden with multi-systemic complications. Through transancestry meta-analysis of genome-wide association studies of estimated glomerular filtration rate (eGFR) and independent replication (n = 1,046,070), we identified 264 associated loci (166 new). Of these,147 were likely to be relevant for kidney function on the basis of associations with the alternative kidney function marker blood urea nitrogen (n = 416,178). Pathway and enrichment analyses, including mouse models with renal phenotypes, support the kidney as the main target organ. A genetic risk score for lower eGFR was associated with clinically diagnosed CKD in 452,264 independent individuals. Colocalization analyses of associations with eGFR among 783,978 European-ancestry individuals and gene expression across 46 human tissues, including tubulo-interstitial and glomerular kidney compartments, identified 17 genes differentially expressed in kidney. Fine-mapping highlighted missense driver variants in 11 genes and kidney-specific regulatory variants. These results provide a comprehensive priority list of molecular targets for translational research.
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| 16. |
- Xiao, Chao, et al.
(författare)
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RBBP6 increases radioresistance and serves as a therapeutic target for preoperative radiotherapy in colorectal cancer
- 2018
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Ingår i: Cancer Science. - : Blackwell Publishing. - 1347-9032 .- 1349-7006. ; 109:4, s. 1075-1087
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Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy (RT) can be used as preoperative treatment to downstage initially unresectable locally rectal carcinoma, but the radioresistance and recurrence remain significant problems. Retinoblastoma binding protein 6 (RBBP6) has been implicated in the regulation of cell cycle, apoptosis and chemoresistance both in vitro and in vivo. This study investigated whether the inhibition of RBBP6 expression would improve radiosensitivity in human colorectal cancer cells. After SW620 and HT29 cells were exposed to radiation, the levels of RBBP6 mRNA and protein increased over time in both two cells. Moreover, a significant reduction in clonogenic survival and a decrease in cell viability in parallel with an obvious increase in cell apoptosis were demonstrated in irradiated RBBP6-knockdown cells. Besides, transfection with RBBP6 shRNA improved levels of G2-M phase arrest which blocked the cells in a more radiosensitive period of the cell cycle. These observations indicated that cell cycle and apoptosis mechanisms may be connected with tumor cell survival following radiotherapy. In vivo, tumor growth rate of nude mice in RBBP6-knockdown group was significantly slower than that in other groups. These results indicated that RBBP6 overexpression could resist colorectal cancer cells against radiation by regulating cell cycle and apoptosis pathways, and inhibition of RBBP6 could enhance radiosensitivity of human colorectal cancer.
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| 17. |
- Xu, Weidong, 1988-, et al.
(författare)
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Rational molecular passivation for high-performance perovskite light-emitting diodes
- 2019
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Ingår i: Nature Photonics. - : Springer Nature Publishing AG. - 1749-4885 .- 1749-4893. ; 13:6, s. 418-424
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Tidskriftsartikel (refereegranskat)abstract
- A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.
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| 18. |
- Yang, Rong, et al.
(författare)
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Oriented Quasi-2D Perovskites for High Performance Optoelectronic Devices
- 2018
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 30:51
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Tidskriftsartikel (refereegranskat)abstract
- Quasi-2D layered organometal halide perovskites have recently emerged as promising candidates for solar cells, because of their intrinsic stability compared to 3D analogs. However, relatively low power conversion efficiency (PCE) limits the application of 2D layered perovskites in photovoltaics, due to large energy band gap, high exciton binding energy, and poor interlayer charge transport. Here, efficient and water-stable quasi-2D perovskite solar cells with a peak PCE of 18.20% by using 3-bromobenzylammonium iodide are demonstrated. The unencapsulated devices sustain over 82% of their initial efficiency after 2400 h under relative humidity of approximate to 40%, and show almost unchanged photovoltaic parameters after immersion into water for 60 s. The robust performance of perovskite solar cells results from the quasi-2D perovskite films with hydrophobic nature and a high degree of electronic order and high crystallinity, which consists of both ordered large-bandgap perovskites with the vertical growth in the bottom region and oriented small-bandgap components in the top region. Moreover, due to the suppressed nonradiative recombination, the unencapsulated photovoltaic devices can work well as light-emitting diodes (LEDs), exhibiting an external quantum efficiency of 3.85% and a long operational lifetime of approximate to 96 h at a high current density of 200 mA cm(-2) in air.
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| 19. |
- Zhang, Weiyi, et al.
(författare)
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Poly(Ionic Liquid)-Derived Graphitic Nanoporous Carbon Membrane Enables Superior Supercapacitive Energy Storage
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 13:9, s. 10261-10271
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Tidskriftsartikel (refereegranskat)abstract
- High energy/power density, capacitance, and long-life cycles are urgently demanded for energy storage electrodes. Porous carbons as benchmark commercial electrode materials are underscored by their (electro)chemical stability and wide accessibility, yet are often constrained by moderate performances associated with their powdery status. Here via controlled vacuum pyrolysis of a poly(ionic liquid) membrane template, advantageous features including good conductivity (132 S cm(-1) at 298 K), interconnected hierarchical pores, large specific surface area (1501 m(2) g(-1)), and heteroatom doping are realized in a single carbon membrane electrode. The structure synergy at multiple length scales enables large areal capacitances both for a basic aqueous electrolyte (3.1 F cm(-2)) and for a symmetric all-solid-state supercapacitor (1.0 F cm(-2)), together with superior energy densities (1.72 and 0.14 mW h cm(-2), respectively) without employing a current collector. In addition, theoretical calculations verify a synergistic heteroatom co-doping effect beneficial to the supercapacitive performance. This membrane electrode is scalable and compatible for device fabrication, highlighting the great promise of a poly(ionic liquid) for designing graphitic nanoporous carbon membranes in advanced energy storage.
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| 20. |
- Zhu, Bin, et al.
(författare)
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Apolipoprotein M Protects Against Lipopolysaccharide-Induced Acute Lung Injury via Sphingosine-1-Phosphate Signaling
- 2018
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Ingår i: Inflammation. - : Springer Science and Business Media LLC. - 0360-3997 .- 1573-2576. ; 41:2, s. 643-653
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: It had been demonstrated that apolipoprotein M (apoM) is an important carrier of sphingosine-1-phosphate (S1P) in blood, and the S1P has critical roles in the pathogenesis of sepsis-induced acute lung injury (ALI). In the present study, we investigated whether apoM has beneficial effects in a mouse model after lipopolysaccharide (LPS)-induced ALI. Forty-eight mice were divided into two groups: male C57BL/6 wild-type (apoM+/+) group (n = 24) and apoM gene-deficient (apoM−/−) group (n = 24) and then randomly subdivided into four subgroups (n = 6 each) according to different intraperitoneal (i.p.) injection: control group, W146 group, LPS group, and LPS + W146 group. Serum levels of interleukin-1 beta (IL-1β) and mRNA levels of IL-1β, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), lung histology, wet/dry weight ratio, and immunohistochemistry were measured at 3 h after the baseline and compared in each group. Our results clearly demonstrated that IL-1β mRNA levels and other inflammatory biomarkers were significantly increased in the lungs of LPS-induced ALI apoM−/− mice compared to those of the apoM+/+ mice. Moreover, when apoM+/+ mice were treated with W146, a S1P receptor (S1PR1) antagonist, these inflammatory biomarkers could be significantly upregulated by LPS-induced ALI. Therefore, it suggests that apoM-S1P-S1PR1 signaling might underlie the pathogenesis of ALI and apoM could have physiological benefits to alleviate LPS-induced ALI.
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| 21. |
- Zou, Wei, et al.
(författare)
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Minimising efficiency roll-off in high-brightness perovskite light-emitting diodes
- 2018
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Efficiency roll-off is a major issue for most types of light-emitting diodes (LEDs), and its origins remain controversial. Here we present investigations of the efficiency roll-off in perovskite LEDs based on two-dimensional layered perovskites. By simultaneously measuring electroluminescence and photoluminescence on a working device, supported by transient photoluminescence decay measurements, we conclude that the efficiency roll-off in perovskite LEDs is mainly due to luminescence quenching which is likely caused by non-radiative Auger recombination. This detrimental effect can be suppressed by increasing the width of quantum wells, which can be easily realized in the layered perovskites by tuning the ratio of large and small organic cations in the precursor solution. This approach leads to the realization of a perovskite LED with a record external quantum efficiency of 12.7%, and the efficiency remains to be high, at approximately 10%, under a high current density of 500 mA cm(-2).
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| 22. |
- Akula, Murali K, et al.
(författare)
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Control of the innate immune response by the mevalonate pathway
- 2016
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Ingår i: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 17:8, s. 922-9
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Tidskriftsartikel (refereegranskat)abstract
- Deficiency in mevalonate kinase (MVK) causes systemic inflammation. However, the molecular mechanisms linking the mevalonate pathway to inflammation remain obscure. Geranylgeranyl pyrophosphate, a non-sterol intermediate of the mevalonate pathway, is the substrate for protein geranylgeranylation, a protein post-translational modification that is catalyzed by protein geranylgeranyl transferase I (GGTase I). Pyrin is an innate immune sensor that forms an active inflammasome in response to bacterial toxins. Mutations in MEFV (encoding human PYRIN) result in autoinflammatory familial Mediterranean fever syndrome. We found that protein geranylgeranylation enabled Toll-like receptor (TLR)-induced activation of phosphatidylinositol-3-OH kinase (PI(3)K) by promoting the interaction between the small GTPase Kras and the PI(3)K catalytic subunit p110 delta. Macrophages that were deficient in GGTase I or p110 delta exhibited constitutive release of interleukin 1 beta that was dependent on MEFV but independent of the NLRP3, AIM2 and NLRC4 inflammasomes. In the absence of protein geranylgeranylation, compromised PI(3)K activity allows an unchecked TLR-induced inflammatory responses and constitutive activation of the Pyrin inflammasome.
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| 23. |
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| 24. |
- Danish, Muhammad, et al.
(författare)
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Efficient transformation of trichloroethylene activated through sodium percarbonate using heterogeneous zeolite supported nano zero valent iron-copper bimetallic composite
- 2017
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 308, s. 396-407
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Tidskriftsartikel (refereegranskat)abstract
- Zeolite supported nano zero valent iron copper bimetallic composite (Z-nZVFe-Cu) was synthesized using an ion exchange method. The morphology and physico-chemical properties of the Z-nZVFe-Cu composite were determined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). The results showed that iron and copper nano particles were well dispersed on the zeolite sheet. The degradation efficiency of trichloroethylene (TCE) achieved was more than 95% using Z-nZVFe-Cu as a heterogeneous Fenton like catalyst. An efficient removal of total organic carbon (TOC) was promoted as compared to zeolite supported iron nano composite (Z-nZVFe) and unsupported nano iron (nZVFe). Electron spin resonance (ESR) detection confirmed the intensity of hydroxyl radicals (OH.) in the system. While benzoic acid (BA), a probe indicator for the quantification of OH., demonstrated the higher intensity of hydroxyl radicals in Z-nZVFe-Cu as compared to Z-nZVFe and nZVFe. The less iron and copper leaching of from Z-nZVFe-Cu presented its higher stability and better catalytic activity, displaying its potential long term applications for TCE degradation in groundwater. (C) 2016 Elsevier B.V. All rights reserved.
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| 25. |
- Danish, Muhammad, et al.
(författare)
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Role of reactive oxygen species and effect of solution matrix in trichloroethylene degradation from aqueous solution by zeolite-supported nano iron as percarbonate activator
- 2016
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Ingår i: Research on chemical intermediates (Print). - : Springer. - 0922-6168 .- 1568-5675. ; 42:9, s. 6959-6973
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Tidskriftsartikel (refereegranskat)abstract
- The role of reactive oxygen species (ROSs) and effect of solution matrix have been investigated for the degradation of trichloroethylene (TCE). Zeolite-supported nano iron (Z-nZVI) was synthesized as an activator to catalyze sodium percarbonate (SPC) with or without hydroxylamine, i.e. as reducing agent (RA). The probe tests confirmed the generation of OH center dot and O-2(-center dot) in the Z-nZVI activated SPC system in absence of the RA, while the presence of RA significantly increased the generation of OH center dot and O-2(-center dot) radicals. Scavenger tests demonstrated that OH center dot was the main ROS responsible for TCE degradation, whereas O-2(-center dot) also participated in TCE degradation. From the solution matrix perspective, the experimental results confirmed significant scavenging effects of Cl- (1.0, 10.0, and 100 mmol L-1) and HCO3- (1.0 and 10.0 mmol L-1), whereas the scavenging effects were fairly impeded at 100 mmol L-1 concentration of HCO3-. On the other hand, a considerable decline in scavenging effect was observed in the presence of RA in tested Cl and HCO3- concentration ranges. In addition, negligible scavenging effects of NO3- and SO42- anions were found in all tested concentrations. The effect of initial solution pH on catalytic activity indicated a significant increase in the TCE degradation in the presence of RA even at higher pH value of 9. The results indicated that the Z-nZVI activated SPC system in presence of RA can effectively degrade chlorinated organic solvents, but it is important to consider the intensive existence of anions in groundwater.
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| 26. |
- Danish, M., et al.
(författare)
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The Effect of Chelating Agents on Enhancement of 1,1,1-Trichloroethane and Trichloroethylene Degradation by Z-nZVI-Catalyzed Percarbonate Process
- 2016
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 227:9
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Tidskriftsartikel (refereegranskat)abstract
- This study primarily focused on the performance of 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE) degradation involving redox reactions in zeolite-supported nanozerovalent iron composite (Z-nZVI)-catalyzed sodium percarbonate (SPC) system in aqueous solution with five different chelating agents (CAs) including oxalic acid (OA), citric acid monohydrate (CAM), glutamic acid (GA), ethylenediaminetetraacetic acid (EDTA), and L-ascorbic acid (ASC). The experimental results showed that the addition of OA achieved almost 100 % degradation of 1,1,1-TCA and TCE. The addition of CAM and GA also significantly increased the contaminant degradation, while excessive addition of them inhibited the degradation. In contrast, EDTA and ASC showed negative impacts on 1,1,1-TCA and TCE degradation, which might be due to the strong reactivity with iron and OH● scavenging characteristics. The efficiency with CA addition on 1,1,1-TCA and TCE degradation decreased in the order of OA > CAM > GA > no CAs > EDTA > ASC. The extensive investigations using probe compound tests and scavenger tests revealed that both contaminants degraded primarily by OH● and O2 –● in chelated Z-nZVI-catalyzed SPC system. The significant improvement in 1,1,1-TCA and TCE degradation efficiency was accredited due to the (i) increase in concentration of Fe2+ and (ii) continuous generation of OH● radicals and maintenance of its quantity, ensuring more stability in the aqueous solution. Finally, the complete mineralization of 1,1,1-TCA and TCE in the OA-chelated, Z-nZVI-catalyzed SPC system was confirmed without any chlorinated intermediate by-products detected, demonstrating a great potential of this technique in the application of groundwater remediation.
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| 27. |
- Eriksson, Erik, 1977, et al.
(författare)
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Participation in a Swedish cervical cancer screening program among women with psychiatric diagnoses: a population-based cohort study.
- 2019
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Ingår i: BMC public health. - : Springer Science and Business Media LLC. - 1471-2458. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, organized screening programs have significantly reduced the incidence of cervical cancer. For cancers overall, however, women with psychiatric diagnoses have lower survival rates than other women. This study explores whether women with psychiatric diagnoses participate in cervical cancer screening programs to a lesser extent than women on average, and whether there are disparities between psychiatric diagnostic groups based on grades of severity.Between 2000 and 2010, 65,292 women within screening ages of 23-60 had at least two ICD-10 (International Statistical Classification of Diseases and Related Health Problems - Tenth Revision) codes F20*-F40* registered at visits in primary care or psychiatric care in Region Västra Götaland, Sweden. Participation in the cervical cancer screening program during 2010-2014 was compared with the general female population using logistic regression adjusted for age.Relative risk for participation (RR) for women diagnosed within psychiatric specialist care RR was 0.94 compared with the general population, adjusted for age. RR for diagnoses outside specialist care was 0.99. RR for psychoses (F20*) was 0.81.Women with less-severe psychiatric diagnoses participate in the screening program to the same extent as women overall. Women who have received psychiatric specialist care participate to a lesser extent than women overall. The lowest participation rates were found among women diagnosed with psychoses.
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| 28. |
- Feng, Yue Hua, et al.
(författare)
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Increased apolipoprotein M induced by lack of scavenger receptor BI is not activated via HDL-mediated cholesterol uptake in hepatocytes
- 2018
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Ingår i: Lipids in Health and Disease. - : Springer Science and Business Media LLC. - 1476-511X. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Scavenger receptor BI (SR-BI) is a classic high-density lipoprotein (HDL) receptor, which mediates selective lipid uptake from HDL cholesterol esters (HDL-C). Apolipoprotein M (ApoM), as a component of HDL particles, could influence preβ-HDL formation and cholesterol efflux. The aim of this study was to determine whether SR-BI deficiency influenced the expression of ApoM. Methods: Blood samples and liver tissues were collected from SR-BI gene knockout mice, and serum lipid parameters, including total cholesterol (TC), triglyceride (TG), high and low-density lipoprotein cholesterol (HDL-C and LDL-C) and ApoM were measured. Hepatic ApoM and ApoAI mRNA levels were also determined. In addition, BLT-1, an inhibitor of SR-BI, was added to HepG2 cells cultured with cholesterol and HDL, under serum or serum-free conditions. The mRNA and protein expression levels of ApoM were detected by RT-PCR and western blot. Results: We found that increased serum ApoM protein levels corresponded with high hepatic ApoM mRNA levels in both male and female SR-BI-/- mice. Besides, serum TC and HDL-C were also significantly increased. Treatment of HepG2 hepatoma cells with SR-BI specific inhibitor, BLT-1, could up-regulate ApoM expression in serum-containing medium but not in serum-free medium, even in the presence of HDL-C and cholesterol. Conclusions: Results suggested that SR-BI deficiency promoted ApoM expression, but the increased ApoM might be independent from HDL-mediated cholesterol uptake in hepatocytes.
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| 29. |
- Fuller, Franklin D, et al.
(författare)
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Drop-on-demand sample delivery for studying biocatalysts in action at X-ray free-electron lasers
- 2017
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Ingår i: Nature Methods. - : Macmillan Publishers Ltd.. - 1548-7091 .- 1548-7105. ; 14, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- X-ray crystallography at X-ray free-electron laser sources is a powerful method for studying macromolecules at biologically relevant temperatures. Moreover, when combined with complementary techniques like X-ray emission spectroscopy, both global structures and chemical properties of metalloenzymes can be obtained concurrently, providing insights into the interplay between the protein structure and dynamics and the chemistry at an active site. The implementation of such a multimodal approach can be compromised by conflicting requirements to optimize each individual method. In particular, the method used for sample delivery greatly affects the data quality. We present here a robust way of delivering controlled sample amounts on demand using acoustic droplet ejection coupled with a conveyor belt drive that is optimized for crystallography and spectroscopy measurements of photochemical and chemical reactions over a wide range of time scales. Studies with photosystem II, the phytochrome photoreceptor, and ribonucleotide reductase R2 illustrate the power and versatility of this method.
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| 30. |
- Hu, Y., et al.
(författare)
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Nonlinear model predictive control for mobile robot using varying-parameter convergent differential neural network
- 2019
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Ingår i: Robotics. - : MDPI AG. - 2218-6581. ; 8:3, s. 64-
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Tidskriftsartikel (refereegranskat)abstract
- The mobile robot kinematic model is a nonlinear affine system, which is constrained by velocity and acceleration limits. Therefore, the traditional control methods may not solve the tracking problem because of the physical constraint. In this paper, we present the nonlinear model predictive control (NMPC) algorithm to track the desired trajectory based on neural-dynamic optimization. In the proposed algorithm, the NMPC scheme utilizes a new neural network named the varying-parameter convergent differential neural network (VPCDNN) which is a Hopfifield-neural network structure with respect to the differential equation theory to solve the quadratic programming (QP) problem. The new network structure converges to the global optimal solution and it is more efficient than traditional numerical methods. In the simulation, we verify that the proposed method is able to successfully track reference trajectories with a two-wheel mobile robot. The experimental validation has been conducted in simulation and the results show that the proposed method is able to precisely track the trajectory maintaining a high robustness based on the VPCDNN solver.
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| 31. |
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| 32. |
- Kabir, Md Alamdir, et al.
(författare)
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Assessing the significant impact of concept drift in software defect prediction
- 2019
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Ingår i: Proceedings - International Computer Software and Applications Conference. - : IEEE Computer Society. - 9781728126074 ; , s. 53-58
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Konferensbidrag (refereegranskat)abstract
- Concept drift is a known phenomenon in software data analytics. It refers to the changes in the data distribution over time. The performance of analytic and prediction models degrades due to the changes in the data over time. To improve prediction performance, most studies propose that the prediction model be updated when concept drift occurs. In this work, we investigate the existence of concept drift and its associated effects on software defect prediction performance. We adopt the strategy of an empirically proven method DDM (Drift Detection Method) and evaluate its statistical significance using the chi-square test with Yates continuity correction. The objective is to empirically determine the concept drift and to calibrate the base model accordingly. The empirical study indicates that the concept drift occurs in software defect datasets, and its existence subsequently degrades the performance of prediction models. Two types of concept drifts (gradual and sudden drifts) were identified using the chi-square test with Yates continuity correction in the software defect datasets studied. We suggest concept drift should be considered by software quality assurance teams when building prediction models. © 2019 IEEE.
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| 33. |
- Kern, Jan, et al.
(författare)
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Structures of the intermediates of Kok’s photosynthetic water oxidation clock
- 2018
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 563, s. 421-425
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by the period-four oscillation in flash-induced oxygen evolution of photosystem II discovered by Joliot in 1969, Kok performed additional experiments and proposed a five-state kinetic model for photosynthetic oxygen evolution, known as Kok’s S-state clock or cycle1,2. The model comprises four (meta)stable intermediates (S0, S1, S2 and S3) and one transient S4 state, which precedes dioxygen formation occurring in a concerted reaction from two water-derived oxygens bound at an oxo-bridged tetra manganese calcium (Mn4CaO5) cluster in the oxygen-evolving complex3–7. This reaction is coupled to the two-step reduction and protonation of the mobile plastoquinone QB at the acceptor side of PSII. Here, using serial femtosecond X-ray crystallography and simultaneous X-ray emission spectroscopy with multi-flash visible laser excitation at room temperature, we visualize all (meta)stable states of Kok’s cycle as high-resolution structures (2.04–2.08 Å). In addition, we report structures of two transient states at 150 and 400 µs, revealing notable structural changes including the binding of one additional ‘water’, Ox, during the S2→S3 state transition. Our results suggest that one water ligand to calcium (W3) is directly involved in substrate delivery. The binding of the additional oxygen Ox in the S3 state between Ca and Mn1 supports O–O bond formation mechanisms involving O5 as one substrate, where Ox is either the other substrate oxygen or is perfectly positioned to refill the O5 position during O2 release. Thus, our results exclude peroxo-bond formation in the S3 state, and the nucleophilic attack of W3 onto W2 is unlikely.
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| 34. |
- Liu, Shudong, et al.
(författare)
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Multi-class dynamic inventory rationing with stochastic demands and backordering
- 2015
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Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217 .- 1872-6860. ; 244:1, s. 153-163
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic inventory rationing is considered for systems with multiple demand classes, stationary stochastic demands, and backordering. In the literature, dynamic programming has been often applied to address this type of problems. However, due to the curse of dimensionality, computation is a critical challenge for dynamic programming. In this paper, an innovative two-step approach is proposed based on an idea similar to the certainty equivalence principle. First the deterministic inventory rationing problem is studied, where the future demands are set to be the expectation of the stochastic demand processes. The important properties obtained from solving the problem with the KKT conditions are then used to develop effective dynamic rationing policies for stochastic demands, which gives closed-form expressions for dynamic rationing thresholds. These expressions are easy to calculate and are applicable to any number of demand classes. Numerical results show that the expressions are close to and provide a lower bound for the optimal dynamic thresholds. They also shed light on important managerial insights, for example, the relation between different parameters and the rationing thresholds.
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| 35. |
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| 36. |
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| 37. |
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| 38. |
- Miao, Yanfeng, et al.
(författare)
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Stable and bright formamidinium-based perovskite light-emitting diodes with high energy conversion efficiency
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Solution-processable perovskites show highly emissive and good charge transport, making them attractive for low-cost light-emitting diodes (LEDs) with high energy conversion efficiencies. Despite recent advances in device efficiency, the stability of perovskite LEDs is still a major obstacle. Here, we demonstrate stable and bright perovskite LEDs with high energy conversion efficiencies by optimizing formamidinium lead iodide films. Our LEDs show an energy conversion efficiency of 10.7%, and an external quantum efficiency of 14.2% without outcoupling enhancement through controlling the concentration of the precursor solutions. The device shows low efficiency droop, i.e. 8.3% energy conversion efficiency and 14.0% external quantum efficiency at a current density of 300 mA cm(-2), making the device more efficient than state-of-the-art organic and quantum-dot LEDs at high current densities. Furthermore, the half-lifetime of device with benzylamine treatment is 23.7 hr under a current density of 100 mA cm(-2), comparable to the lifetime of near-infrared organic LEDs.
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| 39. |
- Morandi, Garrett D., et al.
(författare)
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Elucidating mechanisms of toxic action of dissolved organic chemicals in oil sands process-affected water (OSPW)
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 186, s. 893-900
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Tidskriftsartikel (refereegranskat)abstract
- Oil sands process-affected water (OSPW) is generated during extraction of bitumen in the surface-mining oil sands industry in Alberta, Canada, and is acutely and chronically toxic to aquatic organisms. It is known that dissolved organic compounds in OSPW are responsible for most toxic effects, but knowledge of the specific mechanism(s) of toxicity, is limited. Using bioassay-based effects-directed analysis, the dissolved organic fraction of OSPW has previously been fractionated, ultimately producing refined samples of dissolved organic chemicals in OSPW, each with distinct chemical profiles. Using the Escherichia coli K-12 strain MG1655 gene reporter live cell array, the present study investigated relationships between toxic potencies of each fraction, expression of genes and characterization of chemicals in each of five acutely toxic and one non-toxic extract of OSPW derived by use of effects-directed analysis. Effects on expressions of genes related to response to oxidative stress, protein stress and DNA damage were indicative of exposure to acutely toxic extracts of OSPW. Additionally, six genes were uniquely responsive to acutely toxic extracts of OSPW. Evidence presented supports a role for sulphur- and nitrogen-containing chemical classes in the toxicity of extracts of OSPW.
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| 40. |
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| 41. |
- Schmidt, Torsten, et al.
(författare)
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Nanopore arrays in a silicon membrane for parallel single-molecule detection : fabrication
- 2015
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 26:31
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Tidskriftsartikel (refereegranskat)abstract
- Solid state nanopores enable translocation and detection of single bio-molecules such as DNA in buffer solutions. Here, sub-10 nm nanopore arrays in silicon membranes were fabricated by using electron-beam lithography to define etch pits and by using a subsequent electrochemical etching step. This approach effectively decouples positioning of the pores and the control of their size, where the pore size essentially results from the anodizing current and time in the etching cell. Nanopores with diameters as small as 7 nm, fully penetrating 300 nm thick membranes, were obtained. The presented fabrication scheme to form large arrays of nanopores is attractive for parallel bio-molecule sensing and DNA sequencing using optical techniques. In particular the signal-to-noise ratio is improved compared to other alternatives such as nitride membranes suffering from a high-luminescence background.
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| 42. |
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| 43. |
- Sychugov, Ilya, et al.
(författare)
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Non-stationary analysis of molecule capture and translocation in nanopore arrays
- 2019
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 150:8
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Tidskriftsartikel (refereegranskat)abstract
- Analytical formulas for the ON- and OFF-time distributions as well as for the autocorrelation function were derived for the case of single molecule translocation through nanopore arrays. The obtained time-dependent expressions describe very well experimentally recorded statistics of DNA translocations through an array of solid state nanopores, which allows us to extract molecule and system related physical parameters from the experimental traces. The necessity of non-stationary analysis as opposite to the steady-state approximation has been vindicated for the molecule capture process, where different time-dependent regimes were identified. A long tail in the distribution of translocation times has been rationalized invoking Markov jumps, where a possible sequential ordering of events was elucidated through autocorrelation function analysis.
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| 44. |
- Takeuchi, Fumihiko, et al.
(författare)
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Interethnic analyses of blood pressure loci in populations of East Asian and European descent
- 2018
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Blood pressure (BP) is a major risk factor for cardiovascular disease and more than 200 genetic loci associated with BP are known. Here, we perform a multi-stage genome-wide association study for BP (max N = 289,038) principally in East Asians and meta-analysis in East Asians and Europeans. We report 19 new genetic loci and ancestry-specific BP variants, conforming to a common ancestry-specific variant association model. At 10 unique loci, distinct non-rare ancestry-specific variants colocalize within the same linkage disequilibrium block despite the significantly discordant effects for the proxy shared variants between the ethnic groups. The genome-wide transethnic correlation of causal-variant effect-sizes is 0.898 and 0.851 for systolic and diastolic BP, respectively. Some of the ancestry-specific association signals are also influenced by a selective sweep. Our results provide new evidence for the role of common ancestry-specific variants and natural selection in ethnic differences in complex traits such as BP.
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| 45. |
- Wang, F., et al.
(författare)
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Current status and challenges of the ammonia escape inhibition technologies in ammonia-based CO2 capture process
- 2018
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 230, s. 734-749
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Tidskriftsartikel (refereegranskat)abstract
- CO2 capture using ammonia solvent is an alternative to the conventional amine-based CO2 capture technology. While ammonia escape is one of the main barrier limiting its implementation. The present work reviews the current status of ammonia escape mechanisms and its inhibition technologies. The chemistry of ammonia-based absorption and desorption are analyzed, and the mass transfer of the ammonia escape are presented and discussed. Most suppression approaches for ammonia slip are in lab- and bench-scale studies. The representative development of the pilot-scale tests involves NH3 abatement and recycling process and chilled ammonia process (CAP). Some other novel processes have been reported the potential to reduce ammonia slip significantly and relatively lower energy penalty, but some technical issues including the process modification and parameters optimization should be resolved to secure economic feasibility. Integration of different ammonia inhibition approaches is suggested for the future development of ammonia slip suppression process.
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| 46. |
- Wang, F., et al.
(författare)
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Efficiency evaluation of a coal-fired power plant integrated with chilled ammonia process using an absorption refrigerator
- 2018
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 230, s. 267-276
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Tidskriftsartikel (refereegranskat)abstract
- Chilled ammonia process (CAP) is an alternative process for inhibiting ammonia escape during the CO2 capture process. In this paper, the integration of a coal-fired power plant with CAP, using an absorption refrigerator (AR) to provide the chilling load, is proposed. The thermal energy consumption of the CAP and the AR, derived from a crossover pipe between the intermediate pressure and low pressure (IP-LP) steam turbine sections and from an appropriate port of a low pressure (LP) turbine, are the basic scenarios considered for this study. A systematic evaluation of a 300-MWe coal-fired power plant is conducted and its overall process is compared with the power plant integrated with CAP using the conventional vapor compression refrigerator (VCR). An analysis of the basic scenarios reveals that the efficiency penalties reduced from 13.23% to 9.82% when the steam extractions were from the IP-LP crossover pipe and LP turbine, of which a 4.26% and 2.96% loss, respectively, was contributed by the AR. Decreasing the chilling temperature, while increasing the regenerating temperature can reduce the efficiency penalty. A comparative investigation of the lower efficiency penalties of various COPa and COPc are recommended. Better performance can be achieved by VCR integration if the COPc is higher than 2.0 and 3.5. The results from and an understanding of the two types of refrigerators can be used as the basis for system design and optimization.
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| 47. |
- Wang, Kun, et al.
(författare)
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Attack Detection and Distributed Forensics in Machine-to-Machine Networks
- 2016
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Ingår i: IEEE Network. - Piscataway, NJ : IEEE. - 0890-8044 .- 1558-156X. ; 30:6, s. 49-55
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Tidskriftsartikel (refereegranskat)abstract
- The advanced idea of machine-to-machine technology has attracted a new period of network revolution, evolving into a method to monitor and control global industrial user assets, machines, and the production process. M2M networks are considered to be the intelligent connection and communication between machines. However, the security issues have been further amplified with the development of M2M networks. Consequently, it is essential to pour attention into attack detection and forensics problems in M2M networks. This article puts forward the hybrid attack detection and forensics model in M2M networks. It contains two modules: the attack detection module and the forensics analysis module. In addition, we present a distributed anti-honeypot-based forensics strategy to cope with DDoS attacks in the forensics analysis module. Finally, we also discuss some challenges in M2M network security and forensics.
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| 48. |
- Wang, Nana, et al.
(författare)
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Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells
- 2016
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Ingår i: Nature Photonics. - : NATURE PUBLISHING GROUP. - 1749-4885 .- 1749-4893. ; 10:11, s. 699-
-
Tidskriftsartikel (refereegranskat)abstract
- Organometal halide perovskites can be processed from solutions at low temperatures to form crystalline direct-bandgap semiconductors with promising optoelectronic properties(1-5). However, the efficiency of their electroluminescence is limited by non-radiative recombination, which is associated with defects and leakage current due to incomplete surface coverage(6-9). Here we demonstrate a solution-processed perovskite light-emitting diode (LED) based on self-organized multiple quantum wells (MQWs) with excellent film morphologies. The MQW-based LED exhibits a very high external quantum efficiency of up to 11.7%, good stability and exceptional highpower performance with an energy conversion efficiency of 5.5% at a current density of 100 mA cm(-2). This outstanding performance arises because the lower bandgap regions that generate electroluminescence are effectively confined by perovskite MQWs with higher energy gaps, resulting in very efficient radiative decay. Surprisingly, there is no evidence that the large interfacial areas between different bandgap regions cause luminescence quenching.
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| 49. |
- Wu, Sihan, et al.
(författare)
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Circular ecDNA promotes accessible chromatin and high oncogene expression
- 2019
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Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 575:7784, s. 699-703
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Tidskriftsartikel (refereegranskat)abstract
- Oncogenes are commonly amplified on particles of extrachromosomal DNA (ecDNA) in cancer(1,2), but our understanding of the structure of ecDNA and its effect on gene regulation is limited. Here, by integrating ultrastructural imaging, long-range optical mapping and computational analysis of whole-genome sequencing, we demonstrate the structure of circular ecDNA. Pan-cancer analyses reveal that oncogenes encoded on ecDNA are among the most highly expressed genes in the transcriptome of the tumours, linking increased copy number with high transcription levels. Quantitative assessment of the chromatin state reveals that although ecDNA is packaged into chromatin with intact domain structure, it lacks higher-order compaction that is typical of chromosomes and displays significantly enhanced chromatin accessibility. Furthermore, ecDNA is shown to have a significantly greater number of ultra-long-range interactions with active chromatin, which provides insight into how the structure of circular ecDNA affects oncogene function, and connects ecDNA biology with modern cancer genomics and epigenetics.
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| 50. |
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