| 1861. |
- Burillo, S. G., et al.
(författare)
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Molecular line emission in NGC 1068 imaged with ALMA : I. An AGN-driven outflow in the dense molecular gas
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 567, s. 125-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We investigate the fueling and the feedback of star formation and nuclear activity in NGC 1068, a nearby (D = 14 Mpc) Seyfert 2 barred galaxy, by analyzing the distribution and kinematics of the molecular gas in the disk. We aim to understand if and how gas accretion can self-regulate.Methods. We have used the Atacama Large Millimeter Array (ALMA) to map the emission of a set of dense molecular gas (n(H2) ' 1056 cm3) tracers (CO(3-2), CO(6-5), HCN(4-3), HCO+(4-3), and CS(7-6)) and their underlying continuum emission in the central r ∼ 2 kpc of NGC 1068 with spatial resolutions ∼0:3000:500 (∼20-35 pc for the assumed distance of D = 14 Mpc). Results. The sensitivity and spatial resolution of ALMA give an unprecedented detailed view of the distribution and kinematics of the dense molecular gas (n(H2) ≈ 1056cm3) in NGC 1068. Molecular line and dust continuum emissions are detected from a r ∼ 200 pc off-centered circumnuclear disk (CND), from the 2.6 kpc-diameter bar region, and from the r ∼ 1:3 kpc starburst (SB) ring. Most of the emission in HCO+, HCN, and CS stems from the CND. Molecular line ratios show dramatic order-of-magnitude changes inside the CND that are correlated with the UV/X-ray illumination by the active galactic nucleus (AGN), betraying ongoing feedback. We used the dust continuum fluxes measured by ALMA together with NIR/MIR data to constrain the properties of the putative torus using CLUMPY models and found a torus radius of 20+6 10 pc. The Fourier decomposition of the gas velocity field indicates that rotation is perturbed by an inward radial flow in the SB ring and the bar region. However, the gas kinematics from r ∼ 50 pc out to r ∼ 400 pc reveal a massive (Mmol ∼ 2:7+0:9 1:2 × 107 M) outflow in all molecular tracers. The tight correlation between the ionized gas outflow, the radio jet, and the occurrence of outward motions in the disk suggests that the outflow is AGN driven. Conclusions. The molecular outflow is likely launched when the ionization cone of the narrow line region sweeps the nuclear disk. The outflow rate estimated in the CND, dM=dt ∼ 63+21 37 M yr1, is an order of magnitude higher than the star formation rate at these radii, confirming that the outflow is AGN driven. The power of the AGN is able to account for the estimated momentum and kinetic luminosity of the outflow. The CND mass load rate of the CND outflow implies a very short gas depletion timescale of ≤1 Myr. The CND gas reservoir is likely replenished on longer timescales by efficient gas inflow from the outer disk. © ESO 2014.
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| 1862. |
- Burisch, Johan, et al.
(författare)
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Costs and resource utilization for diagnosis and treatment during the initial year in a European inflammatory bowel disease inception cohort : an ECCO-EpiCom Study
- 2015
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Ingår i: Inflammatory Bowel Diseases. - 1078-0998 .- 1536-4844. ; 21:1, s. 121-131
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: No direct comparison of health care cost in patients with inflammatory bowel disease across the European continent exists. The aim of this study was to assess the costs of investigations and treatment for diagnostics and during the first year after diagnosis in Europe.METHODS: The EpiCom cohort is a prospective population-based inception cohort of unselected inflammatory bowel disease patients from 31 Western and Eastern European centers. Patients were followed every third month from diagnosis, and clinical data regarding treatment and investigations were collected. Costs were calculated in euros (&OV0556;) using the Danish Health Costs Register.RESULTS: One thousand three hundred sixty-seven patients were followed, 710 with ulcerative colitis, 509 with Crohn's disease, and 148 with inflammatory bowel disease unclassified. Total expenditure for the cohort was &OV0556;5,408,174 (investigations: &OV0556;2,042,990 [38%], surgery: &OV0556;1,427,648 [26%], biologicals: &OV0556;781,089 [14%], and standard treatment: &OV0556;1,156,520 [22%)]). Mean crude expenditure per patient in Western Europe (Eastern Europe) with Crohn's disease: investigations &OV0556;1803 (&OV0556;2160) (P = 0.44), surgery &OV0556;11,489 (&OV0556;13,973) (P = 0.14), standard treatment &OV0556;1027 (&OV0556;824) (P = 0.51), and biologicals &OV0556;7376 (&OV0556;8307) (P = 0.31). Mean crude expenditure per patient in Western Europe (Eastern Europe) with ulcerative colitis: investigations &OV0556;1189 (&OV0556;1518) (P < 0.01), surgery &OV0556;18,414 (&OV0556;12,395) (P = 0.18), standard treatment &OV0556;896 (&OV0556;798) (P < 0.05), and biologicals &OV0556;5681 (&OV0556;72) (P = 0.51).CONCLUSIONS: In this population-based unselected cohort, costs during the first year of disease were mainly incurred by investigative procedures and surgeries. However, biologicals accounted for >15% of costs. Long-term follow-up of the cohort is needed to assess the cost-effectiveness of biological agents.
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| 1863. |
- Busa, Asanda V., et al.
(författare)
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New copper(II) salicylaldimine derivatives for mild oxidation of cyclohexane
- 2018
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Ingår i: Journal of Chemical Sciences. - : Springer Science and Business Media LLC. - 0974-3626 .- 0973-7103. ; 130:6
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Two new salicylaldiminato-copper(II) complexes, [Cu(L1)2] (1) and [Cu(L2)2] (2) (where HL1= 4 -tert-Butyl-2-[(thiophen-2-ylmethylimino)-methyl]-phenol and HL2= 2 , 4 -Di-tert-butyl-6-[(thiophen-2-ylmethylimino)-methyl]-phenol), endowed with a pendant thiophenyl moiety, were synthesized and characterized using standard spectroscopic techniques (FT-IR, UV-Vis, MS) and elemental analysis. Complexes 1 and 2 were unequivocally characterized by single crystal X-ray crystallography, which confirmed bidentate bis-chelation of the deprotonated -L1 and -L2 ligands to the copper (II) centres via the phenoxo and imine atoms forming square planar complexes. The copper(II)-hydroperoxo derivatives of 1 and 2 ([(L1)2CuII-OOH] (3) and [(L2)2CuII-OOH] (4)) were also synthesized and the formation of the active intermediate in solution studied. Complexes 1 and 2 were tested as catalyst precursors in cyclohexane oxidation under mild reaction conditions using hydrogen peroxide (H 2O 2) as a terminal oxidant, and were found to catalyse oxidation of the substrate with yields comparable to similar mononuclear and even multinuclear copper complexes. Graphical Abstract: Synopsis Synthesis, characterisation, and molecular structure of salicylaldiminato-copper(II) complexes, and their catalytic evaluation in the oxidation of cyclohexane employing hydrogen peroxide as a terminal oxidant have been studied. The complexes catalysed conversion of cyclohexane with appreciable yields. [Figure not available: see fulltext.].
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| 1864. |
- Buser, Andreas M., et al.
(författare)
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Good modeling practice guidelines for applying multimedia models in chemical assessments
- 2012
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Ingår i: Integrated Environmental Assessment and Management. - : Wiley. - 1551-3777 .- 1551-3793. ; 8:4, s. 703-708
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Tidskriftsartikel (refereegranskat)abstract
- Multimedia mass balance models of chemical fate in the environment have been used for over 3 decades in a regulatory context to assist decision making. As these models become more comprehensive, reliable, and accepted, there is a need to recognize and adopt principles of Good Modeling Practice (GMP) to ensure that multimedia models are applied with transparency and adherence to accepted scientific principles. We propose and discuss 6 principles of GMP for applying existing multimedia models in a decision-making context, namely 1) specification of the goals of the model assessment, 2) specification of the model used, 3) specification of the input data, 4) specification of the output data, 5) conduct of a sensitivity and possibly also uncertainty analysis, and finally 6) specification of the limitations and limits of applicability of the analysis. These principles are justified and discussed with a view to enhancing the transparency and quality of model-based assessments.
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| 1865. |
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| 1866. |
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| 1867. |
- Cai, Bin, et al.
(författare)
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Organic Polymer Dots Photocatalyst for CO2 Reduction in Aqueous Solution
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Developing low-cost and efficient photocatalysts to convert CO2 into valuable fuels is desirable to realize a carbon-neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9′-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT) without adding any extra co-catalyst can photocatalytic reduction of CO2 into CO in aqueous solution, rendering a CO production rate of 57 μmol g-1 h-1 with a detectable selectivity of up to 100%. 5 cycles of CO2 re-purging experiments show no distinct decline in CO amount and reaction rate, indicating the promising photocatalytic stability of PFBT Pdots in photocatalytic CO2 reduction reaction. Mechanistic study reveals that photo-excited PFBT Pdots are reduced by TEOA first, then the reduced PFBT Pdots can bind CO2 and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO2 reduction in the aqueous solution, which therefore provides a strategy to develop highly efficient and environmental-friendly nanoparticular photocatalysts for CO2 reduction.
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| 1868. |
- Cai, Bin, et al.
(författare)
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Organic Polymer Dots Photocatalyze CO2 Reduction in Aqueous Solution
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 62:45
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Tidskriftsartikel (refereegranskat)abstract
- Developing low-cost and efficient photocatalysts to convert CO2 into valuable fuels is desirable to realize a carbon-neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9 ' -dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT), without adding any extra co-catalyst, can photocatalyze reduction of CO2 into CO in aqueous solution, rendering a CO production rate of 57 mu mol g(-1) h(-1 )with a detectable selectivity of up to 100 %. After 5 cycles of CO2 re-purging experiments, no distinct decline in CO amount and reaction rate was observed, indicating the promising photocatalytic stability of PFBT Pdots in the photocatalytic CO2 reduction reaction. A mechanistic study reveals that photoexcited PFBT Pdots are reduced by sacrificial donor first, then the reduced PFBT Pdots can bind CO(2 )and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO2 reduction in aqueous solution, which therefore provides a strategy to develop highly efficient and environmentally friendly nanoparticulate photocatalysts for CO2 reduction.
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| 1869. |
- Caleman, Carl, et al.
(författare)
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A Perspective on Molecular Structure and Bond-Breaking in Radiation Damage in Serial Femtosecond Crystallography
- 2020
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Ingår i: Crystals. - : MDPI. - 2073-4352. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free-electron lasers (XFELs) have a unique capability for time-resolved studies of protein dynamics and conformational changes on femto- and pico-second time scales. The extreme intensity of X-ray pulses can potentially cause significant modifications to the sample structure during exposure. Successful time-resolved XFEL crystallography depends on the unambiguous interpretation of the protein dynamics of interest from the effects of radiation damage. Proteins containing relatively heavy elements, such as sulfur or metals, have a higher risk for radiation damage. In metaloenzymes, for example, the dynamics of interest usually occur at the metal centers, which are also hotspots for damage due to the higher atomic number of the elements they contain. An ongoing challenge with such local damage is to understand the residual bonding in these locally ionized systems and bond-breaking dynamics. Here, we present a perspective on radiation damage in XFEL experiments with a particular focus on the impacts for time-resolved protein crystallography. We discuss recent experimental and modelling results of bond-breaking and ion motion at disulfide bonding sites in protein crystals.
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| 1870. |
- Caleman, Carl, et al.
(författare)
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Modeling of XFEL induced ionization and atomic displacement in protein nanocrystals
- 2012
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Ingår i: Proceedings of SPIE. - : SPIE. - 9780819492210 ; , s. 85040H-
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Konferensbidrag (refereegranskat)abstract
- X-ray free-electron lasers enable high-resolution imaging of biological materials by using short enough pulses to outrun many of the effects of radiation damage. Experiments conducted at the LCLS have obtained diffraction data from single particles and protein nanocrystals at doses to the sample over 3 GGy. The details of the interaction of the X-ray FEL pulse with the sample determine the limits of this new paradigm for imaging. Recent studies suggest that in the case of crystalline samples, such as protein nanocrystals, the atomic displacements and loss of bound electrons in the crystal (due to the high X- ray intensity) has the effect of gating the diffraction signal, and hence making the experiment less radiation sensitive. Only the incident photon intensity in the first part of the pulse, before the Bragg diffraction has died out, is relevant to acquiring signal and the rest of the pulse will mainly contribute to a diffuse background. In this work we use a plasma based non-local thermodynamic equilibrium code to explore the displacement and the ionization of a protein nanocrystal at various X-ray wavelengths and intensities.
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