| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Huang, Liping, et al.
(författare)
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Interim effects of salt substitution on urinary electrolytes and blood pressure in the China Salt Substitute and Stroke Study (SSaSS).
- 2020
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Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 221, s. 136-145
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Tidskriftsartikel (refereegranskat)abstract
- The Salt Substitute and Stroke Study is an ongoing 5-year large-scale cluster randomized trial investigating the effects of potassium-enriched salt substitute compared to usual salt on the risk of stroke. The study involves 600 villages and 20,996 individuals in rural China. Intermediate risk markers were measured in a random subsample of villages every 12 months over 3 years to track progress against key assumptions underlying study design. Measures of 24-hour urinary sodium, 24-hour urinary potassium, blood pressure and participants' use of salt substitute were recorded, with differences between intervention and control groups estimated using generalized linear mixed models. The primary outcome of annual event rate in the two groups combined was determined by dividing confirmed fatal and non-fatal strokes by total follow-up time in the first 2 years. The mean differences (95% CI) were -0.32 g (-0.68 to 0.05) for 24-hour urinary sodium, +0.77 g (+0.60 to +0.93) for 24-hour urinary potassium, -2.65 mmHg (-4.32 to -0.97) for systolic blood pressure and +0.30 mmHg (-0.72 to +1.32) for diastolic blood pressure. Use of salt substitute was reported by 97.5% in the intervention group versus 4.2% in the control group (P<.0001). The overall estimated annual event rate for fatal and non-fatal stroke was 3.2%. The systolic blood pressure difference and the annual stroke rate were both in line with the statistical assumptions underlying study design. The trial should be well placed to address the primary hypothesis at completion of follow-up.
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| 4. |
- Hudson, Thomas J., et al.
(författare)
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International network of cancer genome projects
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7291, s. 993-998
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Tidskriftsartikel (refereegranskat)abstract
- The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
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| 5. |
- Canton, Sophie, et al.
(författare)
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Probing the Anisotropic Distortion of Photoexcited Spin Crossover Complexes with Picosecond X-ray Absorption Spectroscopy
- 2014
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:8, s. 4536-4545
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Tidskriftsartikel (refereegranskat)abstract
- For numerous spin crossover complexes, the anisotropic distortion of the first coordination shell around the transition metal center governs the dynamics of the high-spin/low-spin interconversion. However, this structural parameter remains elusive for samples that cannot be investigated with crystallography. The present work demonstrates how picosecond X-ray absorption spectroscopy is able to capture this specific deformation in the photoinduced high-spin state of solvated [Fe(terpy)(2)](2+), a complex which belongs to the prominent family of spin crossover building blocks with nonequivalent metal-ligand bonds. The correlated changes in Fe-N-Axial, Fe-N-Distal, and bite angle N-Distal-Fe-N-Axial extracted from the measurements are in very good agreement with those predicted by DFT calculations in D-2d symmetry. The outlined methodology is generally applicable to the characterization of ultrafast nuclear rearrangements around metal centers in photoactive molecular complexes and nanomaterials, including those that do not display long-range order.
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| 6. |
- Canton, Sophie, et al.
(författare)
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Toward Highlighting the Ultrafast Electron Transfer Dynamics at the Optically Dark Sites of Photocatalysts
- 2013
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:11, s. 1972-1976
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Tidskriftsartikel (refereegranskat)abstract
- Building a detailed understanding of the structure function relationship is a crucial step in the optimization of molecular photocatalysts employed in water splitting schemes. The optically dark nature of their active sites usually prevents a complete mapping of the photoinduced dynamics. In this work, transient X-ray absorption spectroscopy highlights the electronic and geometric changes that affect such a center in a bimetallic model complex. Upon selective excitation of the ruthenium chromophore, the cobalt moiety is reduced through intramolecular electron transfer and undergoes a spin flip accompanied by an average bond elongation of 0.20 +/- 0.03 angstrom. The analysis is supported by simulations based on density functional theory structures (B3LYP*/TZVP) and FEFF 9.0 multiple scattering calculations. More generally, these results exemplify the large potential of the technique for tracking elusive intermediates that impart unique functionalities in photochemical devices.
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| 7. |
- Locke, Adam E, et al.
(författare)
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Genetic studies of body mass index yield new insights for obesity biology.
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 518:7538, s. 197-401
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P < 5 × 10(-8)), 56 of which are novel. Five loci demonstrate clear evidence of several independent association signals, and many loci have significant effects on other metabolic phenotypes. The 97 loci account for ∼2.7% of BMI variation, and genome-wide estimates suggest that common variation accounts for >20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.
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| 8. |
- Wang, Zhaoming, et al.
(författare)
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Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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| 9. |
- Zhong, Jun, et al.
(författare)
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A Transcriptome-Wide Association Study Identifies Novel Candidate Susceptibility Genes for Pancreatic Cancer
- 2020
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 112:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although 20 pancreatic cancer susceptibility loci have been identified through genome-wide association studies in individuals of European ancestry, much of its heritability remains unexplained and the genes responsible largely unknown. Methods: To discover novel pancreatic cancer risk loci and possible causal genes, we performed a pancreatic cancer transcriptome-wide association study in Europeans using three approaches: FUSION, MetaXcan, and Summary-MulTiXcan. We integrated genome-wide association studies summary statistics from 9040 pancreatic cancer cases and 12 496 controls, with gene expression prediction models built using transcriptome data from histologically normal pancreatic tissue samples (NCI Laboratory of Translational Genomics [n = 95] and Genotype-Tissue Expression v7 [n = 174] datasets) and data from 48 different tissues (Genotype-Tissue Expression v7, n = 74-421 samples). Results: We identified 25 genes whose genetically predicted expression was statistically significantly associated with pancreatic cancer risk (false discovery rate < .05), including 14 candidate genes at 11 novel loci (1p36.12: CELA3B; 9q31.1: SMC2, SMC2-AS1; 10q23.31: RP11-80H5.9; 12q13.13: SMUG1; 14q32.33: BTBD6; 15q23: HEXA; 15q26.1: RCCD1; 17q12: PNMT, CDK12, PGAP3; 17q22: SUPT4H1; 18q11.22: RP11-888D10.3; and 19p13.11: PGPEPI) and 11 at six known risk loci (5p15.33: TERT, CLPTMIL, ZDHHCIIB; 7p14.1: INHBA; 9q34.2: ABO; 13q12.2: PDX1; 13q22.1: KLF5; and 16q23.1: WDR59, CFDP1, BCAR1, TMEM170A). The association for 12 of these genes (CELA3B, SMC2, and PNMT at novel risk loci and TERT, CLPTMIL, INHBA, ABO, PDX1, KLF5, WDR59, CFDP1, and BCAR1 at known loci) remained statistically significant after Bonferroni correction. Conclusions: By integrating gene expression and genotype data, we identified novel pancreatic cancer risk loci and candidate functional genes that warrant further investigation.
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| 10. |
- Biasin, Elisa, et al.
(författare)
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Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated[Co(terpy)2]2$
- 2016
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 1079-7114 .- 0031-9007. ; 117:1
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Tidskriftsartikel (refereegranskat)abstract
- We study the structural dynamics of photoexcited [Co(terpy)2]2+ in an aqueous solution with ultrafast x-ray diffuse scattering experiments conducted at the Linac Coherent Light Source. Through direct comparisons with density functional theory calculations, our analysis shows that the photoexcitation event leads to elongation of the Co-N bonds, followed by coherent Co-N bond length oscillations arising from the impulsive excitation of a vibrational mode dominated by the symmetrical stretch of all six Co-N bonds. This mode has a period of 0.33 ps and decays on a subpicosecond time scale. We find that the equilibrium bond-elongated structure of the high spin state is established on a single-picosecond time scale and that this state has a lifetime of ∼7 ps.
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| 11. |
- Canton, Sophie, et al.
(författare)
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Visualizing the non-equilibrium dynamics of photoinduced intramolecular electron transfer with femtosecond X-ray pulses.
- 2015
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafast photoinduced electron transfer preceding energy equilibration still poses many experimental and conceptual challenges to the optimization of photoconversion since an atomic-scale description has so far been beyond reach. Here we combine femtosecond transient optical absorption spectroscopy with ultrafast X-ray emission spectroscopy and diffuse X-ray scattering at the SACLA facility to track the non-equilibrated electronic and structural dynamics within a bimetallic donor-acceptor complex that contains an optically dark centre. Exploiting the 100-fold increase in temporal resolution as compared with storage ring facilities, these measurements constitute the first X-ray-based visualization of a non-equilibrated intramolecular electron transfer process over large interatomic distances. Experimental and theoretical results establish that mediation through electronically excited molecular states is a key mechanistic feature. The present study demonstrates the extensive potential of femtosecond X-ray techniques as diagnostics of non-adiabatic electron transfer processes in synthetic and biological systems, and some directions for future studies, are outlined.
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| 12. |
- Dai, Yi, et al.
(författare)
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Zn-doped CaFeO3 perovskite-derived high performed catalyst on oxygen reduction reaction in microbial fuel cells
- 2021
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 489
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Tidskriftsartikel (refereegranskat)abstract
- Stable perovskite oxide is considered as a potential cathode for microbial fuel cells (MFCs). Herein, Zn is used as an effective element to modify the micro-structure and oxygen vacancy of perovskite to be a novel cathode catalyst. Physical characterizations show that due to partial volatilization at high temperature of Zn, perovskite forms hierarchically porous structures. Moreover, Zn is precipitated in electrochemical reaction to generate Zn vacancy in situ; thus, the active center of Fe has a superior interaction with oxygen-containing species, promoting the production of oxygen vacancy and forms a mixed valence state of Fe2+/Fe3+. The Zn-doped perovskite material CaFe0.7Zn0.3O3 exhibits remarkable oxygen reduction reaction (ORR) performances with outstanding onset potential (0.194 V vs. Ag/AgCl) and half-wave potential (-0.219 V vs. Ag/AgCl) under alkaline condition, which is better than Pt/C catalyst. Besides, CaFe0.7Zn0.3O3 shows an excellent four-electron pathway of ORR mechanism with remarkable corrosion resistance and stability, which enables a more reliable cathode electrocatalyst. The maximum power density of CaFe0.7Zn0.3O3 (892.10 +/- 90.79 mW m(-3)) testing on microbial fuel cell is comparable to the maximum power density (1012.86 +/- 84.03 mW m(-3)) of Pt/C. The findings of this work provide the feasibility of exploring inexpensive and high-performance cathode catalyst.
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| 13. |
- Evers, Arne, et al.
(författare)
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Testing Practices and Attitudes Toward Tests and Testing : An International Survey
- 2017
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Ingår i: International Journal of Testing. - : ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD. - 1530-5058 .- 1532-7574. ; 17:2, s. 158-190
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Tidskriftsartikel (refereegranskat)abstract
- On behalf of the International Test Commission and the European Federation of Psychologists' Associations a world-wide survey on the opinions of professional psychologists on testing practices was carried out. The main objective of this study was to collect data for a better understanding of the state of psychological testing worldwide. These data could guide the actions and measures taken by ITC, EFPA, and other stakeholders. A questionnaire was administered to 20,467 professional psychologists from 29 countries. Five scales were constructed relating to: concern over incorrect test use, regulations on tests and testing, internet and computerized testing, appreciation of tests, and knowledge and training relating to test use. Equivalence across countries was evaluated using the alignment method, four scales demonstrated acceptable levels of invariance. Multilevel analysis was used to determine how scores were related to age, gender, and specialization, as well as how scores varied between countries. Although the results show a high appreciation of tests in general, the appreciation of internet and computerized testing is much lower. These scales show low variability over countries, whereas differences between countries on the other reported scales are much greater. This implies the need for some overarching improvements as well as country-specific actions.
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| 14. |
- Gao, Yipeng, et al.
(författare)
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Research on the Security of Visual Reasoning CAPTCHA
- 2021
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Ingår i: PROCEEDINGS OF THE 30TH USENIX SECURITY SYMPOSIUM. - : USENIX ASSOC. - 9781939133243 ; , s. 3291-3308
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Konferensbidrag (refereegranskat)abstract
- CAPTCHA is an effective mechanism for protecting computers from malicious bots. With the development of deep learning techniques, current mainstream text-based CAPTCHAs have been proven to be insecure. Therefore, a major effort has been directed toward developing image-based CAPTCHAs, and image-based visual reasoning is emerging as a new direction of such development. Recently, Tencent deployed the Visual Turing Test (VTT) CAPTCHA. This appears to have been the first application of a visual reasoning scheme. Subsequently, other CAPTCHA service providers (Geetest, NetEase, Dingxiang, etc.) have proposed their own visual reasoning schemes to defend against bots. It is, therefore, natural to ask a fundamental question: are visual reasoning CAPTCHAs as secure as their designers expect? This paper presents the first attempt to solve visual reasoning CAPTCHAs. We implemented a holistic attack and a modular attack, which achieved overall success rates of 67.3% and 88.0% on VTT CAPTCHA, respectively. The results show that visual reasoning CAPTCHAs are not as secure as anticipated; this latest effort to use novel, hard AI problems for CAPTCHAs has not yet succeeded. Based on the lessons we learned from our attacks, we also offer some guidelines for designing visual CAPTCHAs with better security.
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| 15. |
- Guo, Xuewen, et al.
(författare)
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Novel small-molecule zwitterionic electrolyte with ultralow work function as cathode modifier for inverted polymer solar cells
- 2018
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Ingår i: Organic electronics. - : ELSEVIER SCIENCE BV. - 1566-1199 .- 1878-5530. ; 59, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- Interfacial compatibility between the electrode and organic semiconductor plays a critical role in controlling the charge transport and hence efficiency of organic solar cell. Here, we introduce a novel small-molecule zwitterionic electrolyte (S1) combined with ZnO as electron transporting interlayer employed for the inverted PTB7:PC71BM bulk heterojunction solar cell. The resulting device with the S1/ZnO stacked interlayer achieves a high PCE of 8.59%, obtaining a 16.2% improvement over the control device performance of 7.4% without the S1 attributed to the significant increased short-circuit current density and fill factor. The interfacial properties are investigated. It is found that the S1/ZnO interlayer possess an ultralow work function of 3.6 eV, which originates from the interfacial double dipole step induced by the zwitterionic side chain electrostatic realignment at interface. The S1/ZnO interlayer exhibits the excellent charge extraction ability, suppresses the charge recombination loss and decreases the series resistance at the active layer/electrode contact.
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| 16. |
- Guo, Xuewen, et al.
(författare)
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Understanding the effect of N2200 on performance of J71 : ITIC bulk heterojunction in ternary non-fullerene solar cells
- 2019
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Ingår i: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 71, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- None-fullerene solar cells with ternary architecture have attracted much attention because it is an effective approach for boosting the device power conversion efficiency. Here, the crystalline polymer N2200 as the third component is integrated into J71: ITIC bulk heterojunction. A series of characterizations indicate that N2200 could increase photo-harvesting, balanced hole and electron mobilities, enhanced exciton dissociation, and suppressed charge recombination, which result in the comprehensive improvement of open circuit voltage, short circuit current and fill factor in the device. Moreover, after introduction of N2200, the morphology of the ternary active layer is optimized, and the film crystallinity is improved. This work demonstrates that adding a small quantity of high crystallization acceptor into non-fullerene donor: acceptor mixture is a promising strategy toward developing high-performance organic solar cells.
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| 17. |
- Liang, Jianxin, et al.
(författare)
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Mechanistic study of transcription factor Sox18 during heart development
- 2024
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 350
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Tidskriftsartikel (refereegranskat)abstract
- Heart development is a delicate and complex process regulated by coordination of various signaling pathways. In this study, we investigated the role of sox18 in heart development by modulating Wnt/β-Catenin signaling pathways. Our spatiotemporal expression analysis revealed that sox18 is mainly expressed in the heart, branchial arch, pharyngeal arch, spinal cord, and intersegmental vessels at the tailbud stage of Xenopus tropicalis embryo. Overexpression of sox18 in the X. tropicalis embryos causes heart edema, while loss-of-function of sox18 can change the signal of developmental heart marker gata4 at different stages, suggesting that sox18 plays an essential role in the development of the heart. Knockdown of SOX18 in human umbilical vein endothelial cells suggests a link between Sox18 and β-CATENIN, a key regulator of the Wnt signaling pathway. Sox18 negatively regulates islet1 and tbx3, the downstream factors of Wnt/β-Catenin signaling, during the linear heart tube formation and the heart looping stage. Taken together, our findings highlight the crucial role of Sox18 in the development of the heart via inhibiting Wnt/β-Catenin signaling.
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| 18. |
- Liu, Jianxin, et al.
(författare)
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A novel methodology to directly pre-determine the relative wavelength response of DFB laser in wavelength modulation spectroscopy
- 2019
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 27:2, s. 1249-1261
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Tidskriftsartikel (refereegranskat)abstract
- A novel methodology to directly pre-determine the relative wavelength response (RWR) of a DFB laser, in terms of a combined current linearly scanned wavelength response and current modulated wavelength response (CMWR), in wavelength modulation spectroscopy (WMS) is presented. It is shown that the assessed RWR can be used to mimic the measured response with standard deviation of discriminations that are below 3.4 x 10(-3)cm(-1) under a variety of conditions. It is also shown that its performance supersedes two commonly used assessment models of the CMWR but is slightly worse than that of the third model. however with the benefit of solely using a single fitting parameter (the concentration) instead of more. When the novel method is applied to the assessment of CO2 concentration in a Herriot-type multipass cell by using the technique of calibration-free WMS, the results show that there is virtually no difference compared to that by use of the best of the other methods. It is concluded that the novel method is more robust and simplifies the retrieval process of gas concentration.
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| 19. |
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| 20. |
- Naumova, Maria A., et al.
(författare)
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Exploring the light-induced dynamics in solvated metallogrid complexes with femtosecond pulses across the electromagnetic spectrum
- 2020
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Ingår i: The Journal of chemical physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 152:21
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Tidskriftsartikel (refereegranskat)abstract
- Oligonuclear complexes of d4-d7 transition metal ion centers that undergo spin-switching have long been developed for their practical role in molecular electronics. Recently, they also have appeared as promising photochemical reactants demonstrating improved stability. However, the lack of knowledge about their photophysical properties in the solution phase compared to mononuclear complexes is currently hampering their inclusion into advanced light-driven reactions. In the present study, the ultrafast photoinduced dynamics in a solvated [2 × 2] iron(II) metallogrid complex are characterized by combining measurements with transient optical-infrared absorption and x-ray emission spectroscopy on the femtosecond time scale. The analysis is supported by density functional theory calculations. The photocycle can be described in terms of intra-site transitions, where the FeII centers in the low-spin state are independently photoexcited. The Franck-Condon state decays via the formation of a vibrationally hot high-spin (HS) state that displays coherent behavior within a few picoseconds and thermalizes within tens of picoseconds to yield a metastable HS state living for several hundreds of nanoseconds. Systematic comparison with the closely related mononuclear complex [Fe(terpy)2]2+ reveals that nuclearity has a profound impact on the photoinduced dynamics. More generally, this work provides guidelines for expanding the integration of oligonuclear complexes into new photoconversion schemes that may be triggered by ultrafast spin-switching.
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| 21. |
- Naumova, Maria A., et al.
(författare)
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Revealing Hot and Long-Lived Metastable Spin States in the Photoinduced Switching of Solvated Metallogrid Complexes with Femtosecond Optical and X-ray Spectroscopies
- 2020
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 11:6, s. 2133-2141
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Tidskriftsartikel (refereegranskat)abstract
- An atomistic understanding of the photoinduced spin-state switching (PSS) within polynuclear systems of d4-d7 transition metal ion complexes is required for their rational integration into light-driven reactions of chemical and biological interest. However, in contrast to mononuclear systems, the multidimensional dynamics of the PSS in solvated molecular arrays have not yet been elucidated due to the expected complications associated with the connectivity between the metal centers and the strong interactions with the surroundings. In this work, the PSS in a solvated triiron(II) metallogrid complex is characterized using transient optical absorption and X-ray emission spectroscopies on the femtosecond time scale. The complementary measurements reveal the photoinduced creation of energy-rich (hot) and long-lived quintet states, whose dynamics differ critically from their mononuclear congeners. This finding opens major prospects for developing novel schemes in solution-phase spin chemistry that are driven by the dynamic PSS process in compact oligometallic arrays.
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| 22. |
- Speliotes, Elizabeth K., et al.
(författare)
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Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:11, s. 937-948
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ~2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10−8), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation.
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| 23. |
- Wang, Hongyu, et al.
(författare)
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Co/Fe co-doped ZIF-8 derived hierarchically porous composites as high-performance electrode materials for Cu2+ions capacitive deionization
- 2023
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Ingår i: Chemical Engineering Journal. - : ELSEVIER SCIENCE SA. - 1385-8947 .- 1873-3212. ; 460
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Tidskriftsartikel (refereegranskat)abstract
- Due to a threat to human life from heavy metal ions pollution, unprecedented interest has been gained in the development of water purification technologies. Here, we explore another new approach to exploit a prospective carbon material for removing copper ions from aqueous solution based on rapid and easy capacitive deionization (CDI). Reasonable carbon materials modification with ideal composition and improved morphological structure is essential to additionally optimize the capabilities of CDI. We prepared a nitrogen-rich hierarchically porous carbon composites (CoFe-NC) with uniform cobalt (Co) and iron (Fe) doped metal in carbon skeleton by a simple impregnation and pyrolysis method, derived from zeolitic imidazolate framework-8, to use as highly effective CDI electrode for copper ions removal. The addition of Fe can facilitate the uniform dispersion of metals, and enable the formation of a stable carbon cage after pyrolysis. It can sufficiently expose active sites of the electrode materials and promote interfacial charge transfer, thus improving CDI electrosorption efficiency. CoFe-NC composites electrode can achieve outstanding deionization capacity (91.31 mg g-1) in 25 mg L-1 CuSO4 solu-tion. The carbon cage structure of CoFe-NC not only prevents aggregation of metals and avoids destruction of rich multistage pore system by pyrolysis, but also induces a faster ions transport rate. In addition, density functional theory calculations demonstrated that the co-doping of Co and Fe can remarkably increase the adsorption en-ergies of Cu2+ ions, leading to excellent selectivity, which indicates that CoFe-NC composites can be a desired CDI electrode material.
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| 24. |
- Weiguang, Ma, et al.
(författare)
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Review on Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy
- 2018
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Ingår i: Chinese Journal of Lasers-Zhongguo Jiguang. - : Chinese Laser Press. - 0258-7025. ; 45:9
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Forskningsöversikt (refereegranskat)abstract
- Noise immune cavity enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) can provide the highest detection sensitivity in the field of laser absorption spectroscopy by combining two techniques of frequency modulation spectroscopy and cavity enhanced absorption spectroscopy. The principle and implementation process of NICE-OHMS arc introduced. Then, the historical development of NICE-OHMS is overviewed, which mainly focuses on the key parameters, such as the applied laser source and the cavity finesse used by each research group and their obtained detection sensitivity. Finally, the limitation factors of the detection sensitivity of NICE-OHMS arc analyzed, and the related solutions arc provided.
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| 25. |
- Yang, Jianming, et al.
(författare)
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Comprehensive understanding of heat-induced degradation of triple-cation mixed halide perovskite for a robust solar cell
- 2018
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Ingår i: Nano Energy. - : ELSEVIER SCIENCE BV. - 2211-2855 .- 2211-3282. ; 54, s. 218-226
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Tidskriftsartikel (refereegranskat)abstract
- The triple-cation mixed halide perovskite Cs-0.05(MA(0.17)FA(0.83))(0.95)Pb(I0.83Br0.17)(3) emerges as one of the most promising candidates for photovoltaics due to superior optoelectronic properties, but the thermal stability is still a major challenge for the viability of perovskite solar cells towards commercialization. Herein, we firstly explore the thermal response of the photovoltaic performances to access device physical changes. It is shown that the efficiency loss originates from decreased charge mobility, increased trap density and generation of PbI2 charge recombination centers near the interface. In-depth analysis of evolutions in morphology, chemical composition, dynamic and electronic structure of the perovskite layer at the nanometer scales indicates that it is initial dangling bonds and vacancies on the imperfect surfaces decrease the activation energy and cause the perovskite decomposition in a layer-by-layer pathway sequentially from the film surface to bulk. Based on the results, a strategy of surface passivation to improve the thermal stability is demonstrated and discussed. This work for the first time provides insights into the physical and chemical change of such triple-cation perovskite and indicates that more effort should be invested in surface treatment for enhancing perovskite device stability.
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| 26. |
- Yang, Jianming, et al.
(författare)
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Extremely Low-Cost and Green Cellulose Passivating Perovskites for Stable and High-Performance Solar Cells
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 11:14, s. 13491-13498
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Tidskriftsartikel (refereegranskat)abstract
- The fast evolution of metal halide perovskite solar cells has opened a new chapter in the field of renewable energy. High-quality perovskite films as the active layers are essential for both high efficiency and long-term stability. Here, the perovskite films with enlarged crystal grain size and decreased defect density are fabricated by introducing the extremely low-cost and green polymer, ethyl cellulose (EC), into the perovskite layer. The addition of EC triggers hydrogen bonding interactions between EC and the perovskite, passivating the charge defect traps at the grain boundaries. The long chain of EC further acts as a scaffold for the perovskite structure, eliminating the annealing-induced lattice strain during the film fabrication process. The resulting devices with the EC additive exhibit a remarkably enhanced average power conversion efficiency from 17.11 to 19.27% and an improvement of all device parameters. The hysteresis index is found to decrease by three times from 0.081 to 0.027, which is attributed to suppressed ion migration and surface charge trapping. In addition, the defect passivation by EC significantly improves the environmental stability of the perovskite films, yielding devices that retain 80% of their initial efficiency after 30 days in ambient air at 45% relative humidity, whereas the pristine devices without EC fully degrade. This work provides a low-cost and green avenue for passivating defects that improves both the efficiency and operational stability of perovskite solar cells.
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| 27. |
- Zhang, Hongguo, et al.
(författare)
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Rational design of porous Fex-N@MOF as a highly efficient catalyst for oxygen reduction over a wide pH range
- 2023
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 944
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen reduction reaction (ORR) kinetics are well known to strongly rely on the activives of electro-catalysts. Herein, a Fe-N-doped porous carbon-based electrocatalyst combined with zinc (Zn)-based metal-organic frameworks (MOFs) (Fex-N@MOF) was designed and successfully fabricated via a facile process combined immersion doping and pyrolysis. By controlling the formation of Fe3C, the physical structure of porous carbon was significantly altered, and the active chemical sites of Fe species can be formed to catalyze ORR. The uniform N-doped three-dimensional interpenetrating network structure yielded a high surface area. Both Fe3C and Fe-Nx could offer an abundance of active sites and thus promoted Fe0.05-N@MOF to exhibit high ORR activity in alkaline, neutral and acid electrolytes. Fe0.05-N@MOF showed extraordinary stability and methanol tolerance under a varied pH range conditions, it could be applied as cathode elec-trocatalyst in different fuel cells such as Zn-air fuel cell (ZFC), microbial fuel cells (MFCs), as well as direct methanol fuel cell (DMFC). Fe0.05-N@MOF is a promising material to replace Pt-based electrocatalysts as non-precious metal catalysts.(c) 2023 Elsevier B.V. All rights reserved.
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| 28. |
- Zhang, Jianxin, et al.
(författare)
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Education for Today, Tomorrow and Generations : Forum on the Research of the Education Sustainable Development
- 2012
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Ingår i: Academy. - : Yunnan People's Publishing House. - 1674-4810. ; 2, s. 56-66
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Development is the premise of sustainable development: people are the focus of sustainable development; education for sustainable development (ESD) is based on the needs of sustainable development and education. "China - Sweden's Training of Collaboratively Comparative Research on ESD" organized by Yunnan provincial Federation of Social Science Circle and Swiss International programme office (IPO) launched the new exploration to the creative idea of ESD. In the graduate course named "ESD Research", graduates and scholars air their own views on ESD.
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| 29. |
- Zhang, Tongwu, et al.
(författare)
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Cell-type-specific eQTL of primary melanocytes facilitates identification of melanoma susceptibility genes
- 2018
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 28:11, s. 1621-1635
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Tidskriftsartikel (refereegranskat)abstract
- Most expression quantitative trait locus (eQTL) studies to date have been performed in heterogeneous tissues as opposed to specific cell types. To better understand the cell-type-specific regulatory landscape of human melanocytes, which give rise to melanoma but account for <5% of typical human skin biopsies, we performed an eQTL analysis in primary melanocyte cultures from 106 newborn males. We identified 597,335 cis-eQTL SNPs prior to linkage disequilibrium (LD) pruning and 4997 eGenes (FDR < 0.05). Melanocyte eQTLs differed considerably from those identified in the 44 GTEx tissue types, including skin. Over a third of melanocyte eGenes, including key genes in melanin synthesis pathways, were unique to melanocytes compared to those of GTEx skin tissues or TCGA melanomas. The melanocyte data set also identified trans-eQTLs, including those connecting a pigmentation-associated functional SNP with four genes, likely through cis-regulation of IRF4. Melanocyte eQTLs are enriched in cis-regulatory signatures found in melanocytes as well as in melanoma-associated variants identified through genome-wide association studies. Melanocyte eQTLs also colocalized with melanoma GWAS variants in five known loci. Finally, a transcriptome-wide association study using melanocyte eQTLs uncovered four novel susceptibility loci, where imputed expression levels of five genes (ZFP90, HEBP1, MSC, CBWD1, and RP11-383H13.1) were associated with melanoma at genome-wide significant P-values. Our data highlight the utility of lineage-specific eQTL resources for annotating GWAS findings, and present a robust database for genomic research of melanoma risk and melanocyte biology.
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| 30. |
- Zhou, Yueting, et al.
(författare)
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Laser frequency stabilization based on a universal sub-Doppler NICE-OHMS instrumentation for the potential application in atmospheric lidar
- 2019
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Ingår i: Atmospheric Measurement Techniques. - Gottingen : Copernicus Gesellschaft MBH. - 1867-1381 .- 1867-8548. ; 12:3, s. 1807-1814
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Tidskriftsartikel (refereegranskat)abstract
- Lidar is an effective tool for high-altitude atmospheric measurement in which a weak absorption line for the target gas is selected to ensure a large optical depth. The laser frequency stabilization to the line center is required, and a sub-Doppler (sD) spectroscopy of the target line is preferred as a frequency reference. In this paper, a novel universal sD noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) instrumentation based on a fiber-coupled optical single-sideband electro-optic modulator (f-SSM) for the potential application in atmospheric lidar for different target gases with different types of lasers is reported. The f-SSM can replace all frequency actuators in the system, so as to eliminate the individual design of feedback servos that often are tailored for each laser. The universality of the instrumentation was demonstrated by the alternative use of either an Er-doped fiber laser or a whispering-gallery mode laser. Then the instruments based on both lasers were used to produce the sD signals of acetylene, which worked as a frequency reference to stabilize the laser. By performing the lockings, relative frequency stabilizations of 8.3 x 10(-13) and 7.5 x 10(-13) at an integration time of 240 s were demonstrated.
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