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1.
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2.
  • Klionsky, Daniel J., et al. (författare)
  • Guidelines for the use and interpretation of assays for monitoring autophagy
  • 2012
  • Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
  • 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.
  • Arzoumanian, Doris, et al. (författare)
  • Dust polarized emission observations of NGC 6334: BISTRO reveals the details of the complex but organized magnetic field structure of the high-mass star-forming hub-filament network
  • 2021
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 647
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. Molecular filaments and hubs have received special attention recently thanks to new studies showing their key role in star formation. While the (column) density and velocity structures of both filaments and hubs have been carefully studied, their magnetic field (B-field) properties have yet to be characterized. Consequently, the role of B-fields in the formation and evolution of hub-filament systems is not well constrained. Aims. We aim to understand the role of the B-field and its interplay with turbulence and gravity in the dynamical evolution of the NGC 6334 filament network that harbours cluster-forming hubs and high-mass star formation. Methods. We present new observations of the dust polarized emission at 850 μm toward the 2 pc × 10 pc map of NGC 6334 at a spatial resolution of 0.09 pc obtained with the James Clerk Maxwell Telescope (JCMT) as part of the B-field In STar-forming Region Observations (BISTRO) survey. We study the distribution and dispersion of the polarized intensity (PI), the polarization fraction (PF), and the plane-of-The-sky B-field angle (χB_POS) toward the whole region, along the 10 pc-long ridge and along the sub-filaments connected to the ridge and the hubs. We derived the power spectra of the intensity and χBPOS along the ridge crest and compared them with the results obtained from simulated filaments. Results. The observations span 3 orders of magnitude in Stokes I and PI and 2 orders of magnitude in PF (from 0.2 to 20%). A large scatter in PI and PF is observed for a given value of I. Our analyses show a complex B-field structure when observed over the whole region ( 10 pc); however, at smaller scales (1 pc), χBPOS varies coherently along the crests of the filament network. The observed power spectrum of χBPOS can be well represented with a power law function with a slope of-1.33 ± 0.23, which is 20% shallower than that of I. We find that this result is compatible with the properties of simulated filaments and may indicate the physical processes at play in the formation and evolution of star-forming filaments. Along the sub-filaments, χBPOS rotates frombeing mostly perpendicular or randomly oriented with respect to the crests to mostly parallel as the sub-filaments merge with the ridge and hubs. This variation of the B-field structure along the sub-filaments may be tracing local velocity flows of infalling matter in the ridge and hubs. Our analysis also suggests a variation in the energy balance along the crests of these sub-filaments, from magnetically critical or supercritical at their far ends to magnetically subcritical near the ridge and hubs. We also detect an increase in PF toward the high-column density (NH2 â 1023 cm-2) star cluster-forming hubs. These latter large PF values may be explained by the increase in grain alignment efficiency due to stellar radiation from the newborn stars, combined with an ordered B-field structure. Conclusions. These observational results reveal for the first time the characteristics of the small-scale (down to 0.1 pc) B-field structure of a 10 pc-long hub-filament system. Our analyses show variations in the polarization properties along the sub-filaments that may be tracing the evolution of their physical properties during their interaction with the ridge and hubs. We also detect an impact of feedback from young high-mass stars on the local B-field structure and the polarization properties, which could put constraints on possible models for dust grain alignment and provide important hints as to the interplay between the star formation activity and interstellar B-fields.
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4.
  • Ching, Tao-Chung, et al. (författare)
  • The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
  • 2022
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We present 850 mu m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and similar to 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.
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5.
  • Doi, Yasuo, et al. (författare)
  • The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333
  • 2020
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 899:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We present new observations of the active star formation region NGC 1333 in the Perseus molecular cloud complex from the James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. The BISTRO data cover the entire NGC 1333 complex (∼1.5 pc ? 2 pc) at 0.02 pc resolution and spatially resolve the polarized emission from individual filamentary structures for the first time. The inferred magnetic field structure is complex as a whole, with each individual filament aligned at different position angles relative to the local field orientation. We combine the BISTRO data with low- and high- resolution data derived from Planck and interferometers to study the multiscale magnetic field structure in this region. The magnetic field morphology drastically changes below a scale of ∼1 pc and remains continuous from the scales of filaments (∼0.1 pc) to that of protostellar envelopes (∼0.005 pc or ∼1000 au). Finally, we construct simple models in which we assume that the magnetic field is always perpendicular to the long axis of the filaments. We demonstrate that the observed variation of the relative orientation between the filament axes and the magnetic field angles are well reproduced by this model, taking into account the projection effects of the magnetic field and filaments relative to the plane of the sky. These projection effects may explain the apparent complexity of the magnetic field structure observed at the resolution of BISTRO data toward the filament network.
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6.
  • Karoly, Janik, et al. (författare)
  • The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
  • 2023
  • Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 952:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We present observations of polarized dust emission at 850 mu m from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (N-H2 similar to 10(22) - 10(23) cm(-2)) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to similar to 160 +/- 30 mu G in the main starless core and up to similar to 90 +/- 40 mu G in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvenic. We also present a new method of data reduction for these denser but fainter objects like starless cores.
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7.
  • Kwon, Woojin, et al. (författare)
  • B-fields in Star-forming Region Observations (BISTRO): Magnetic Fields in the Filamentary Structures of Serpens Main
  • 2022
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 926:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We present 850 mu m polarimetric observations toward the Serpens Main molecular cloud obtained using the POL-2 polarimeter on the James Clerk Maxwell Telescope as part of the B-fields In STar-forming Region Observations survey. These observations probe the magnetic field morphology of the Serpens Main molecular cloud on about 6000 au scales, which consists of cores and six filaments with different physical properties such as density and star formation activity. Using the histogram of relative orientation (HRO) technique, we find that magnetic fields are parallel to filaments in less-dense filamentary structures where NH2 < 0.93 x 10(22) cm(-2) (magnetic fields perpendicular to density gradients), while they are perpendicular to filaments (magnetic fields parallel to density gradients) in dense filamentary structures with star formation activity. Moreover, applying the HRO technique to denser core regions, we find that magnetic field orientations change to become perpendicular to density gradients again at NH2 approximate to 4.6 x 10(22) NH2 approximate to 16 x 10(22) cm(-2), magnetic fields change back to being parallel to density gradients once again, which can be understood to be due to magnetic fields being dragged in by infalling material. In addition, we estimate the magnetic field strengths of the filaments (B-POS = 60-300 mu G)) using the Davis-Chandrasekhar-Fermi method and discuss whether the filaments are gravitationally unstable based on magnetic field and turbulence energy densities.
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8.
  • Lyo, A-Ran, et al. (författare)
  • The JCMT BISTRO Survey: An 850/450 mu m Polarization Study of NGC 2071IR in Orion B
  • 2021
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 918:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the results of simultaneous 450 mu m and 850 mu m polarization observations toward the massive star-forming region NGC 2071IR, a target of the BISTRO (B-fields in STar-forming Region Observations) Survey, using the POL-2 polarimeter and SCUBA-2 camera mounted on the James Clerk Maxwell Telescope. We find a pinched magnetic field morphology in the central dense core region, which could be due to a rotating toroidal disklike structure and a bipolar outflow originating from the central young stellar object IRS 3. Using the modified Davis-Chandrasekhar-Fermi method, we obtain a plane-of-sky magnetic field strength of 563 +/- 421 mu G in the central similar to 0.12 pc region from 850 mu m polarization data. The corresponding magnetic energy density of 2.04 x 10(-8) erg cm(-3) is comparable to the turbulent and gravitational energy densities in the region. We find that the magnetic field direction is very well aligned with the whole of the IRS 3 bipolar outflow structure. We find that the median value of polarization fractions is 3.0% at 450 mu m in the central 3 ' region, which is larger than the median value of 1.2% at 850 mu m. The trend could be due to the better alignment of warmer dust in the strong radiation environment. We also find that polarization fractions decrease with intensity at both wavelengths, with slopes, determined by fitting a Rician noise model of 0.59 +/- 0.03 at 450 mu m and 0.36 +/- 0.04 at 850 mu m, respectively. We think that the shallow slope at 850 mu m is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects.
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9.
  • Ngoc, Nguyen Bich, et al. (författare)
  • Observations of Magnetic Fields Surrounding LkH alpha 101 Taken by the BISTRO Survey with JCMT-POL-2
  • 2021
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 908:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the first high spatial resolution measurement of magnetic fields surrounding LkH alpha 101, part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 mu m is found to be mostly associated with the redshifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of B-POS similar to 115 mu G. The mass-to-magnetic-flux ratio in critical value units, lambda similar to 0.3, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkH alpha 101 region is subcritical, and the magnetic field is strong enough to prevent gravitational collapse. The inferred delta B/B-0 similar to 0.3 implies that the large-scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power law with an index of alpha = 0.82 0.03, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkH alpha 101) in the region. Magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques can potentially explain such a decreasing trend.
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10.
  • Tahani, Mehrnoosh, et al. (författare)
  • JCMT BISTRO Observations: Magnetic Field Morphology of Bubbles Associated with NGC 6334
  • 2023
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 944:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the Hii regions associated with the NGC 6334 molecular cloud observed in the submillimeter and taken as part of the B-fields In STar-forming Region Observations Survey. In particular, we investigate the polarization patterns and magnetic field morphologies associated with these Hii regions. Through polarization pattern and pressure calculation analyses, several of these bubbles indicate that the gas and magnetic field lines have been pushed away from the bubble, toward an almost tangential (to the bubble) magnetic field morphology. In the densest part of NGC 6334, where the magnetic field morphology is similar to an hourglass, the polarization observations do not exhibit observable impact from Hii regions. We detect two nested radial polarization patterns in a bubble to the south of NGC 6334 that correspond to the previously observed bipolar structure in this bubble. Finally, using the results of this study, we present steps (incorporating computer vision; circular Hough transform) that can be used in future studies to identify bubbles that have physically impacted magnetic field lines.
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11.
  • Hwang, Jihye, et al. (författare)
  • The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
  • 2022
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We present and analyze observations of polarized dust emission at 850 μm toward the central 1 × 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis–Chandrasekhar–Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from Herschel data and the C18O (J = 3 - 2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 ± 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 ± 0.02. Additionally, the mean Alfvén Mach number is 0.35 ± 0.01. This suggests that, in Mon R2, the magnetic fields provide resistance against large-scale gravitational collapse, and the magnetic pressure exceeds the turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically subcritical.
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12.
  • Jeon, Jae Bum, et al. (författare)
  • Photo-annealed amorphous titanium oxide for perovskite solar cells
  • 2019
  • Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 11:41, s. 19488-19496
  • Tidskriftsartikel (refereegranskat)abstract
    • Electron selective layers are important to the efficiency, stability and hysteresis of perovskite solar cells. Photo-annealing is a low-cost, roll-to-roll-compatible process that can be applied to the post-treatment fabrication of sol-gel based metal oxide layers. Here, we fabricate an amorphous titanium oxide electron selective layer at a low temperature in a dry atmosphere using a UV light annealing system and compare it with a thermal annealing process. Active oxygen species are created by using UV light to promote hydrolysis and condense the TiO2 precursor, which removes organic ligands effectively. The photo-annealed TiO2-based perovskite solar cell has a power conversion efficiency of 19.37% without hysteresis.
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13.
  • Lee, Hyun-Seob, et al. (författare)
  • Foxa2 and Nurr1 Synergistically Yield A9 Nigral Dopamine Neurons Exhibiting Improved Differentiation, Function, and Cell Survival
  • 2010
  • Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 28:3, s. 501-512
  • Tidskriftsartikel (refereegranskat)abstract
    • Effective dopamine (DA) neuron differentiation from neural precursor cells (NPCs) is prerequisite for precursor/stem cell-based therapy of Parkinson's disease (PD). Nurr1, an orphan nuclear receptor, has been reported as a transcription factor that can drive DA neuron differentiation from non-dopaminergic NPCs in vitro. However, Nurr1 alone neither induces full neuronal maturation nor expression of proteins found specifically in midbrain DA neurons. In addition, Nurr1 expression is inefficient in inducing DA phenotype expression in NPCs derived from certain species such as mouse and human. We show here that Foxa2, a forkhead transcription factor whose role in midbrain DA neuron development was recently revealed, synergistically cooperates with Nurr1 to induce DA phenotype acquisition, midbrain-specific gene expression, and neuronal maturation. Thus, the combinatorial expression of Nurr1 and Foxa2 in NPCs efficiently yielded fully differentiated nigral (A9)-type midbrain neurons with clearly detectable DA neuronal activities. The effects of Foxa2 in DA neuron generation were observed regardless of the brain regions or species from which NPCs were derived. Furthermore, DA neurons generated by ectopic Foxa2 expression were more resistant to toxins. Importantly, Foxa2 expression resulted in a rapid cell cycle exit and reduced cell proliferation. Consistently, transplantation of NPCs transduced with Nurr1 and Foxa2 generated grafts enriched with midbrain-type DA neurons but reduced number of proliferating cells, and significantly reversed motor deficits in a rat PD model. Our findings can be applied to ongoing attempts to develop an efficient and safe precursor/stem cell-based therapy for PD. STEM CELLS 2010; 28: 501-512
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14.
  • Son, Ora, et al. (författare)
  • ATHB12, an ABA-Inducible Homeodomain-Leucine Zipper (HD-Zip) Protein of Arabidopsis, Negatively Regulates the Growth of the Inflorescence Stem by Decreasing the Expression of a Gibberellin 20-Oxidase Gene
  • 2010
  • Ingår i: Plant and Cell Physiology. - : Oxford University Press (OUP). - 0032-0781 .- 1471-9053. ; 51:9, s. 1537-1547
  • Tidskriftsartikel (refereegranskat)abstract
    • Arabidopsis thaliana homeobox 12 (ATHB12) is rapidly induced by ABA and water stress. A T-DNA insertion mutant of ATHB12 with a reduced level of ATHB12 expression in stems had longer inflorescence stems and reduced sensitivity to ABA during germination. A high level of transcripts of gibberellin 20-oxidase 1 (GA20ox1), a key enzyme in the synthesis of gibberellins, was detected in athb12 stems, while transgenic lines overexpressing ATHB12 (A12OX) had a reduced level of GA20ox1 in stems. Consistent with these data, ABA treatment of wild-type plants resulted in decreased GA20ox1 expression whereas ABA treatment of the athb12 mutant gave rise to slightly decreased GA20ox1 expression. Retarded stem growth in 3-week-old A12OX plants was rescued by exogenous GA(9), but not by GA(12), and less GA(9) was detected in A12OX stems than in wild-type stems. These data imply that ATHB12 decreases GA20ox1 expression in stems. On the other hand, the stems of A12OX plants grew rapidly after the first 3 weeks, so that they were almost as high as wild-type plants at about 5 weeks after germination. We also found changes in the stems of transgenic plants overexpressing ATHB12, such as alterations of expression GA20ox and GA3ox genes, and of GA(4) levels, which appear to result from feedback regulation. Repression of GA20ox1 by ATHB12 was confirmed by transfection of leaf protoplasts. ABA-treated protoplasts also showed increased ATHB12 expression and reduced GA20ox1 expression. These findings all suggest that ATHB12 negatively regulates the expression of a GA 20-oxidase gene in inflorescence stems.
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15.
  • Eswaraiah, Chakali, et al. (författare)
  • The JCMT BISTRO Survey: Revealing the Diverse Magnetic Field Morphologies in Taurus Dense Cores with Sensitive Submillimeter Polarimetry
  • 2021
  • Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 912:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We have obtained sensitive dust continuum polarization observations at 850 μm in the B213 region of Taurus using POL-2 on SCUBA-2 at the James Clerk Maxwell Telescope as part of the B-fields in STar-forming Region Observations (BISTRO) survey. These observations allow us to probe magnetic field (B-field) at high spatial resolution (∼2000 au or ∼0.01 pc at 140 pc) in two protostellar cores (K04166 and K04169) and one prestellar core (Miz-8b) that lie within the B213 filament. Using the Davis-Chandrasekhar-Fermi method, we estimate the B-field strengths in K04166, K04169, and Miz-8b to be 38 ± 14, 44 ± 16, and 12 ± 5 μG, respectively. These cores show distinct mean B-field orientations. The B-field in K04166 is well ordered and aligned parallel to the orientations of the core minor axis, outflows, core rotation axis, and large-scale uniform B-field, in accordance with magnetically regulated star formation via ambipolar diffusion taking place in K04166. The B-field in K04169 is found to be ordered but oriented nearly perpendicular to the core minor axis and large-scale B-field and not well correlated with other axes. In contrast, Miz-8b exhibits a disordered B-field that shows no preferred alignment with the core minor axis or large-scale field. We found that only one core, K04166, retains a memory of the large-scale uniform B-field. The other two cores, K04169 and Miz-8b, are decoupled from the large-scale field. Such a complex B-field configuration could be caused by gas inflow onto the filament, even in the presence of a substantial magnetic flux.
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16.
  • Hirao, Yuki, et al. (författare)
  • OGLE-2017-BLG-0406 : Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk
  • 2020
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 160:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the Spitzer satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of q = 7.0 x 10(-4) from the light-curve modeling. The ground-only and Spitzer-only data each provide very strong one-dimensional (1D) constraints on the 2D microlens parallax vector pi(E). When combined, these yield a precise measurement of pi(E) and of the masses of the host M-host = 0.56 +/- 0.07 M-circle dot and planet M-planet = 0.41 +/- 0.05 M-Jup. The system lies at a distance D-L = 5.2 +/- 0.5 kpc from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is a(perpendicular to) = 3.5 +/- 0.3 au (i.e., just over twice the snow line). The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the Gaia proper-motion measurement of the source suffers from a catastrophic 10 sigma error.
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17.
  • Kim, Kwangwoo, et al. (författare)
  • High-density genotyping of immune loci in Koreans and Europeans identifies eight new rheumatoid arthritis risk loci
  • 2015
  • Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 74:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective A highly polygenic aetiology and high degree of allele-sharing between ancestries have been well elucidated in genetic studies of rheumatoid arthritis. Recently, the high-density genotyping array Immunochip for immune disease loci identified 14 new rheumatoid arthritis risk loci among individuals of European ancestry. Here, we aimed to identify new rheumatoid arthritis risk loci using Korean-specific Immunochip data. Methods We analysed Korean rheumatoid arthritis case-control samples using the Immunochip and genome-wide association studies (GWAS) array to search for new risk alleles of rheumatoid arthritis with anticitrullinated peptide antibodies. To increase power, we performed a meta-analysis of Korean data with previously published European Immunochip and GWAS data for a total sample size of 9299 Korean and 45 790 European case-control samples. Results We identified eight new rheumatoid arthritis susceptibility loci (TNFSF4, LBH, EOMES, ETS1-FLI1, COG6, RAD51B, UBASH3A and SYNGR1) that passed a genome-wide significance threshold (p<5x10(-8)), with evidence for three independent risk alleles at 1q25/TNFSF4. The risk alleles from the seven new loci except for the TNFSF4 locus (monomorphic in Koreans), together with risk alleles from previously established RA risk loci, exhibited a high correlation of effect sizes between ancestries. Further, we refined the number of single nucleotide polymorphisms (SNPs) that represent potentially causal variants through a trans-ethnic comparison of densely genotyped SNPs. Conclusions This study demonstrates the advantage of dense-mapping and trans-ancestral analysis for identification of potentially causal SNPs. In addition, our findings support the importance of T cells in the pathogenesis and the fact of frequent overlap of risk loci among diverse autoimmune diseases.
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18.
  • Park, Seung Hyun, et al. (författare)
  • Nonpharmaceutical interventions reduce the incidence and mortality of COVID-19: A study based on the survey from the International COVID-19 Research Network (ICRN)
  • 2023
  • Ingår i: Journal of Medical Virology. - : WILEY. - 0146-6615 .- 1096-9071. ; 95:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The recently emerged novel coronavirus, "severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)," caused a highly contagious disease called coronavirus disease 2019 (COVID-19). It has severely damaged the worlds most developed countries and has turned into a major threat for low- and middle-income countries. Since its emergence in late 2019, medical interventions have been substantial, and most countries relied on public health measures collectively known as nonpharmaceutical interventions (NPIs). We aimed to centralize the accumulative knowledge of NPIs against COVID-19 for each country under one worldwide consortium. International COVID-19 Research Network collaborators developed a cross-sectional online survey to assess the implications of NPIs and sanitary supply on the incidence and mortality of COVID-19. The survey was conducted between January 1 and February 1, 2021, and participants from 92 countries/territories completed it. The association between NPIs, sanitation supplies, and incidence and mortality were examined by multivariate regression, with the log-transformed value of population as an offset value. The majority of countries/territories applied several preventive strategies, including social distancing (100.0%), quarantine (100.0%), isolation (98.9%), and school closure (97.8%). Individual-level preventive measures such as personal hygiene (100.0%) and wearing facial masks (94.6% at hospitals; 93.5% at mass transportation; 91.3% in mass gathering facilities) were also frequently applied. Quarantine at a designated place was negatively associated with incidence and mortality compared to home quarantine. Isolation at a designated place was also associated with reduced mortality compared to home isolation. Recommendations to use sanitizer for personal hygiene reduced incidence compared to the recommendation to use soap. Deprivation of masks was associated with increased incidence. Higher incidence and mortality were found in countries/territories with higher economic levels. Mask deprivation was pervasive regardless of economic level. NPIs against COVID-19 such as using sanitizer, quarantine, and isolation can decrease the incidence and mortality of COVID-19.
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19.
  • Shvartzvald, Yossi, et al. (författare)
  • Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf
  • 2019
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 157:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 +/- 1 M-J or 20 +/- 1 M-J. This is the lowest isolated-object mass measurement to date, only similar to 45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 +/- 0.1 kpc or 4.1 +/- 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population.
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20.
  • Wang, Zhaoming, et al. (författare)
  • 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
  • Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
  • 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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21.
  • Kim, Byeong Jo, et al. (författare)
  • High-Efficiency Flexible Perovskite Solar Cells Enabled by an Ultrafast Room-Temperature Reactive Ion Etching Process
  • 2020
  • Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:6, s. 7125-7134
  • Tidskriftsartikel (refereegranskat)abstract
    • Perovskite solar cells (PSCs), which have surprisingly emerged in recent years, are now aiming at commercialization. Rapid, low-temperature, and continuous fabrication processes that can produce high-efficiency PSCs with a reduced fabrication cost and shortened energy payback time are important challenges on the way to commercialization. Herein, we report a reactive ion etching (RIE) method, which is an ultrafast room-temperature technique, to fabricate mesoporous TiO2 (mp-TiO2) as an electron transport layer for high-efficiency PSCs. Replacing the conventional high-temperature annealing process by RIE reduces the total processing time for fabricating 20 PSCs by 40%. Additionally, the RIE-processed mp-TiO2 exhibits enhanced electron extraction, whereupon the optimized RIE-mp-TiO2-based PSC exhibits a power conversion efficiency (PCE) of 19.60% without J–V hysteresis, when the devices were optimized with a TiCl4 surface treatment process. Finally, a flexible PSC employing RIE-mp-TiO2 is demonstrated with 17.29% PCE. Considering that the RIE process has been actively used in the semiconductor industry, including for the fabrication of silicon photovoltaic modules, the process developed in this work could be easily applied toward faster, simpler, and cheaper manufacturing of PSC modules.
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22.
  •  
23.
  • Park, Sung-Joon, et al. (författare)
  • Autonomous Interfacial Assembly of Polymer Nanofilms via Surfactant-Regulated Marangoni Instability
  • 2023
  • Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 23:11, s. 4822-4829
  • Tidskriftsartikel (refereegranskat)abstract
    • Interfacialpolymerization (IP) provides a versatile platform forfabricating defect-free functional nanofilms for various applications,including molecular separation, energy, electronics, and biomedicalmaterials. Unfortunately, coupled with complex natural instabilityphenomena, the IP mechanism and key parameters underlying the structuralevolution of nanofilms, especially in the presence of surfactantsas an interface regulator, remain puzzling. Here, we interfaciallyassembled polymer nanofilm membranes at the free water-oilinterface in the presence of differently charged surfactants and comprehensivelycharacterized their structure and properties. Combined with computationalsimulations, an in situ visualization of interfacial film formationdiscovered the critical role of Marangoni instability induced by thesurfactants via various mechanisms in structurally regulating thenanofilms. Despite their different instability-triggering mechanisms,the delicate control of the surfactants enabled the fabrication ofdefect-free, ultra-permselective nanofilm membranes. Our study identifiescritical IP parameters that allow us to rationally design nanofilms,coatings, and membranes for target applications.
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24.
  • Yoo, Taekyeong, et al. (författare)
  • Disease-specific eQTL screening reveals an anti-fibrotic effect of AGXT2 in non-alcoholic fatty liver disease.
  • 2021
  • Ingår i: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 75:3, s. 514-523
  • Tidskriftsartikel (refereegranskat)abstract
    • Nonalcoholic fatty liver disease (NAFLD) poses an impending clinical burden. Genome-wide association studies have revealed a limited contribution of genomic variants to the disease, requiring alternative but robust approaches to identify disease-associated variants and genes. We carried out a disease-specific expression quantitative trait loci (eQTL) screen to identify novel genetic factors that specifically act on NAFLD progression on the basis of genotype.We recruited 125 Korean biopsy-proven NAFLD patients and healthy individuals and performed eQTL analyses using 21,272 transcripts and 3,234,941 genotyped and imputed SNPs. We then selected eQTLs that were detected only in the NAFLD group, but not in the control group (i.e., NAFLD-eQTLs). An additional cohort of 162 Korean NAFLD individuals was used for replication. The function of the selected eQTL toward NAFLD development was validated using HepG2, primary hepatocytes and NAFLD mouse models.The NAFLD-specific eQTL screening yielded 242 loci. Among them, AGXT2, encoding alanine-glyoxylate aminotransferase 2, displayed decreased expression in NAFLD patients homozygous for the non-reference allele of rs2291702, compared to no-NAFLD subjects with the same genotype (P = 4.79 × 10-6). This change was replicated in an additional 162 individuals, yielding a combined P-value of 8.05 × 10-8 from a total of 245 NAFLD patients and 48 controls. Knockdown of AGXT2 induced palmitate-overloaded hepatocyte death by increasing ER stress, and exacerbated NAFLD diet-induced liver fibrosis in mice. However, overexpression of AGXT2 reversely attenuated liver fibrosis and steatosis as well.We implicate a new molecular role of AGXT2 in NAFLD. Our overall approach will serve as an efficient tool for uncovering novel genetic factors that contribute to liver steatosis and fibrosis in patients with NAFLD.Elucidating causal genes for NAFLD has been challenging due to limited tissue availability and the polygenic nature of the disease. Using liver and blood samples from 125 biopsy-proven NAFLD and no-NAFLD Korean individuals and an additional 162 individuals for replication, we devised a new analytic method to identify causal genes. Among the candidates, we found that AGXT2-rs2291702 protects against liver fibrosis in a genotype-dependent manner with the potential for therapeutic interventions. Our approach enables the discovery of NAFLD causal genes that act on the basis of genotype.
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25.
  • Jeon, So-hyoun, et al. (författare)
  • Selective control of wetting on various substrates
  • 2014
  • Ingår i: Materials research bulletin. - : Elsevier Ltd. - 0025-5408 .- 1873-4227. ; 58, s. 32-34
  • Tidskriftsartikel (refereegranskat)abstract
    • Selective control of wetting is highly demanded for a broad window of applications. To selectively control wetting a surface should be locally modified by structuring surfaces or modulating surface chemistry. However, the local modifications are still challenging due to their complex and expensive processes. In this report we demonstrate the development of a facile approach for selective control of wetting on various substrates. Taking superhydrophobic polypropylene particles and hydrophilic silica nanoparticles, we here show that the locally controlled wetting can be achieved by coating the particles on a wide range of substrates including metal and paper and be applied to microfluidic channels. Furthermore, we represent that the coating method can be applied to any surfaces regardless of compositions and geometries.
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26.
  • Jeong, Heesu, et al. (författare)
  • Room-Temperature-Grown amorphous Indium-Tin-Silicon-Oxide thin film as a new electron transporting layer for perovskite solar cells
  • 2022
  • Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 581
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the amorphous quaternary oxide, indium-tin-silicon-oxide (ITSO), thin film as a new electron transport layer (ETL) for perovskite solar cells (PSCs). ITSO thin films are grown by magnetron co-sputtering indium-tin-oxide (ITO) and silicon oxide (SiO2) on commercial transparent conducting oxide (TCO) thin films at room temperature. As Si content increases (0-53.8 at%) the optical bandgap increases by approximately 1.3 eV and the electrical resistivity increases by six orders mainly because of the carrier concentration decrease. Consequently, the ITSO electronic structure depends largely on Si content. PSCs employing ITSO thin films as ETLs were fabricated to evaluate the effect of Si content on device performances. Si content influenced the shunt and series resistance. The optimized device was obtained using an ITSO film with 33.0 at% Si content, exhibiting 14.50% power-conversion efficiency. These results demonstrate that ITSO films are promising for developing efficient PSCs by optimizing the growing process and/or In/Sn/Si/O compositions. This approach can reduce PSC manufacturing process time and costs if ITO and ITSO are grown together by continuous sequential sputtering in a dual gun (ITO and SiO2) chamber.
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27.
  • Kim, Chan-Hee, et al. (författare)
  • A three-step proteolytic cascade mediates the activation of the peptidoglycan-induced toll pathway in an insect
  • 2008
  • Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 283:12, s. 7599-7607
  • Tidskriftsartikel (refereegranskat)abstract
    • The recognition of lysine-type peptidoglycans (PG) by the PG recognition complex has been suggested to cause activation of the serine protease cascade leading to the processing of Spätzle and subsequent activation of the Toll signaling pathway. So far, two serine proteases involved in the lysine-type PG Toll signaling pathway have been identified. One is a modular serine protease functioning as an initial enzyme to be recruited into the lysine-type PG recognition complex. The other is the Drosophila Spätzle processing enzyme (SPE), a terminal enzyme that converts Spätzle pro-protein to its processed form capable of binding to the Toll receptor. However, it remains unclear how the initial PG recognition signal is transferred to Spätzle resulting in Toll pathway activation. Also, the biochemical characteristics and mechanism of action of a serine protease linking the modular serine protease and SPE have not been investigated. Here, we purified and cloned a novel upstream serine protease of SPE that we named SAE, SPE-activating enzyme, from the hemolymph of a large beetle, Tenebrio molitor larvae. This enzyme was activated by Tenebrio modular serine protease and in turn activated the Tenebrio SPE. The biochemical ordered functions of these three serine proteases were determined in vitro, suggesting that the activation of a three-step proteolytic cascade is necessary and sufficient for lysine-type PG recognition signaling. The processed Spätzle by this cascade induced antibacterial activity in vivo. These results demonstrate that the three-step proteolytic cascade linking the PG recognition complex and Spätzle processing is essential for the PG-dependent Toll signaling pathway.
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28.
  • Lee, Dong Geon, et al. (författare)
  • High Efficiency Perovskite Solar Cells Exceeding 22% via a Photo-Assisted Two-Step Sequential Deposition
  • 2021
  • Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 31:9
  • Tidskriftsartikel (refereegranskat)abstract
    • One of the most effective methods to achieve high-performance perovskite solar cells (PSCs) is to employ additives as crystallization agents or to passivate defects. Tri-iodide ion has been known as an efficient additive to improve the crystallinity, grain size, and morphology of perovskite films. However, the generation and control of this tri-iodide ion are challenging. Herein, an efficient method to produce tri-iodide ion in a precursor solution using a photoassisted process for application in PSCs is developed. Results suggest that the tri-iodide ion can be synthesized rapidly when formamidinium iodide (FAI) dissolved isopropyl alcohol (IPA) solution is exposed to LED light. Specifically, the photoassisted FAI-IPA solution facilitates the formation of fine perovskite films with high crystallinity, large grain size, and low trap density, thereby improving the device performance up to 22%. This study demonstrates that the photoassisted process in FAI dissolved IPA solution can be an alternative strategy to fabricate highly efficient PSCs with significantly reduced processing times.
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29.
  • Mun, Bong-Gyu, et al. (författare)
  • Analysis of transcription factors among differentially expressed genes induced by drought stress in Populus davidiana
  • 2017
  • Ingår i: 3 Biotech. - : Springer. - 2190-5738 .- 2190-572X. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Populus davidiana is native to the Korean Peninsula and is one of the most dominant and abundantly growing forest trees in eastern Asia. Compared to other Populus species such as P. trichocarpa, P. euphratica, and P. tremula, relatively little is known about P. davidiana. Here, we performed transcriptomic analysis of P. davidiana under drought stress induced by 10% polyethylene glycol. A total of 12,403 and 12,414 differentially expressed genes (DEGs) were successfully annotated with the P. trichocarpa reference genome after 6 and 12 h of treatment, respectively. Of these, a total of 404 genes (238 up-regulated and 166 down-regulated) after 6 h and 359 genes (187 up-regulated and 172 down-regulated) after 12 h of treatment were identified as transcription factors. Transcription factors known to be key genes for drought stress response, such as AP2-EREB, WRKY, C2H2, and NAC, were identified. This results suggesting that early induction of these genes affected initiation of transcriptional regulation in response to drought stress. Quantitative real-time PCR results of selected genes showed highly significant (R = 0.93) correlation with RNA-Seq data. Interestingly, the expression pattern of some transcription factors was P. davidiana specific. The sequence of P. davidiana ortholog of P. trichocarpa gene POPTR_0018s10230, which plays an important role in plant response to drought, was further analyzed as our RNA-Seq results showed highly significant changes in the expression of this gene following the stress treatment. Sequence of the gene was compared to P. trichocarpa gene sequence using cloning-based sequencing. Additionally, we generated a predicted 3D protein structure for the gene product. Results indicated that the amino acid sequence of P. davidiana-specific POPTR_0018s10230 is different at six different positions compared to P. trichocarpa, resulting in a significantly different structure of the protein. Identifying the transcription factors expressed in P. davidiana under drought stress will not only offer clues for understanding the underlying mechanisms involved in drought stress physiology but also serve as a basis for future molecular studies on this species.
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30.
  • Park, Chanyong, et al. (författare)
  • Efficient separation of large particles and giant cancer cells using an isosceles trapezoidal spiral microchannel
  • 2024
  • Ingår i: The Analyst. - : ROYAL SOC CHEMISTRY. - 0003-2654 .- 1364-5528.
  • Tidskriftsartikel (refereegranskat)abstract
    • Polyploid giant cancer cells (PGCCs) contribute to the genetic heterogeneity and evolutionary dynamics of tumors. Their size, however, complicates their isolation from mainstream tumor cell populations. Standard techniques like fluorescence-activated cell sorting (FACS) rely on fluorescent labeling, introducing potential challenges in subsequent PGCC analyses. In response, we developed the Isosceles Trapezoidal Spiral Microchannel (ITS mu C), a microfluidic device optimizing the Dean drag force (FD) and exploiting uniform vortices for enhanced separation. Numerical simulations highlighted ITS mu C's advantage in producing robust FD compared to rectangular and standard trapezoidal channels. Empirical results confirmed its ability to segregate larger polystyrene (PS) particles (avg. diameter: 50 mu m) toward the inner wall, while directing smaller ones (avg. diameter: 23 mu m) outward. Utilizing ITS mu C, we efficiently isolated PGCCs from doxorubicin-resistant triple-negative breast cancer (DOXR-TNBC) and patient-derived cancer (PDC) cells, achieving outstanding purity, yield, and viability rates (all greater than 90%). This precision was accomplished without fluorescent markers, and the versatility of ITS mu C suggests its potential in differentiating a wide range of heterogeneous cell populations. Polyploid giant cancer cells (PGCCs) contribute to the genetic heterogeneity and evolutionary dynamics of tumors.
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31.
  • Sampson, Joshua N., et al. (författare)
  • Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
  • 2015
  • Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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32.
  • Thomas, Minta, et al. (författare)
  • Combining Asian and European genome-wide association studies of colorectal cancer improves risk prediction across racial and ethnic populations
  • 2023
  • Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Polygenic risk scores (PRS) have great potential to guide precision colorectal cancer (CRC) prevention by identifying those at higher risk to undertake targeted screening. However, current PRS using European ancestry data have sub-optimal performance in non-European ancestry populations, limiting their utility among these populations. Towards addressing this deficiency, we expand PRS development for CRC by incorporating Asian ancestry data (21,731 cases; 47,444 controls) into European ancestry training datasets (78,473 cases; 107,143 controls). The AUC estimates (95% CI) of PRS are 0.63(0.62-0.64), 0.59(0.57-0.61), 0.62(0.60-0.63), and 0.65(0.63-0.66) in independent datasets including 1681-3651 cases and 8696-115,105 controls of Asian, Black/African American, Latinx/Hispanic, and non-Hispanic White, respectively. They are significantly better than the European-centric PRS in all four major US racial and ethnic groups (p-values < 0.05). Further inclusion of non-European ancestry populations, especially Black/African American and Latinx/Hispanic, is needed to improve the risk prediction and enhance equity in applying PRS in clinical practice.
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33.
  • Chae, Jung-woo, et al. (författare)
  • A simple pharmacokinetic model of alendronate developed using plasma concentration and urine excretion data from healthy men
  • 2014
  • Ingår i: Drug Development and Industrial Pharmacy. - : Informa UK Limited. - 0363-9045 .- 1520-5762. ; 40:10, s. 1325-1329
  • Tidskriftsartikel (refereegranskat)abstract
    • The study of pharmacokinetics of alendronate has been hampered by difficulties in accurately and reproducibly determining their concentrations in serum and urine. Thus, pharmacokinetic characteristics of alendronate have been described in many reports based on urinary excretion data; and plasma pharmacokinetics and the simultaneous pharmacokinetic models of alendronate in plasma and urine are not available. The aims of this study were to measure alendronate concentration in plasma and excretion in urine concurrently and to develop compartmental pharmacokinetic model using urine data. In open-label, single-dose pharmacokinetic study, 10 healthy male volunteers received oral dose of alendronate (70mg tablet). Blood and urine alendronate concentrations were determined using validated high-performance liquid chromatography method. Non-compartmental analysis was performed using WinNonlin program (Pharsight Inc., Apex, NC). A one-compartment pharmacokinetic model was applied to describe pharmacokinetics of alendronate. A peak plasma alendronate concentration of 33.10 +/- 14.32 ng/mL was attained after 1.00 +/- 0.16 h. The cumulative amount of alendronate excreted in urine and peak excretion rate were 731.28 +/- 654.57 mu g and 314.68 +/- 395.43 mg/h, respectively. The model, which included first-order absorption rate for oral dosing, showed good fit to alendronate data obtained from plasma and urine. The absorption rate constant was 2.68 +/- 0.95 h(-1). The elimination rate constants K-urine and Knon-ur were 0.005 +/- 0.004 h(-1) and 0.42 +/- 0.08 h(-1), respectively. The pharmacokinetics of alendronate in plasma and urine of healthy men can be predicted using one-compartment model, and thus the behavior of drug in plasma can be estimated from urinary excretion data.
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34.
  • Chae, Jung-woo, et al. (författare)
  • BSA and ABCB1 polymorphism affect the pharmacokinetics of sunitinib and its active metabolite in Asian mRCC patients receiving an attenuated sunitinib dosing regimen
  • 2016
  • Ingår i: Cancer Chemotherapy and Pharmacology. - : Springer Science and Business Media LLC. - 0344-5704 .- 1432-0843. ; 78:3, s. 623-632
  • Tidskriftsartikel (refereegranskat)abstract
    • An attenuated dosing (AD) sunitinib regimen of 37.5 mg daily has been suggested to reduce the toxicity reported with the standard dosing regimen to metastatic renal cell carcinoma (mRCC) patients. The aim of this study was to characterize the population pharmacokinetic (PK) properties of sunitinib and SU12662, the active metabolite, in patients receiving the AD regimen and to ascertain significant covariates influencing PK parameters. Thirty-one mRCC patients receiving AD sunitinib regimen were included. Plasma samples were collected on day 29 of each treatment cycle after the start of the therapy. Nonlinear mixed-effects modeling was applied to estimate the population PK properties of sunitinib and SU12662 as well as the effect of covariates on PK parameters. Monte Carlo simulation was also performed to predict the total trough level (TTL) of sunitinib and SU12662. Sunitinib population means for CL/F and V (d) /F (central) were 13.8 L/h and 1720 L, respectively. SU12662 population means for CL/F and V (d) /F were 42.1 L/h and 1410 L, respectively. Body surface area (BSA) and ABCB1 polymorphism significantly influenced the CL/F variability of sunitinib: CL/F (parent) = 13.8 x exp((BSA - 1.75) x 2.08 + (ABCB1 (genotype) - 0.67) x 0.61), ABCB1-0: wild genotype, 1: mutant genotype. The effect size of ABCB1 mutant genotype and BSA greater than 1.75 m(2) in relation to sunitinib clearance was 31.14 % (p = 0.006) and 22.11 % (p = 0.011), respectively, relative to the reference group. Adjusting doses of sunitinib according to BSA and ABCB1 polymorphism in Asian mRCC patients may be recommended for sufficient attainment of a target TTL of sunitinib and its metabolite.
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35.
  • Chen, Zhishan, et al. (författare)
  • Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
  • 2024
  • Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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36.
  • Fernandez-Rozadilla, Ceres, et al. (författare)
  • Deciphering colorectal cancer genetics through multi-omic analysis of 100,204 cases and 154,587 controls of European and east Asian ancestries
  • 2023
  • Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 55, s. 89-99
  • Tidskriftsartikel (refereegranskat)abstract
    • Colorectal cancer (CRC) is a leading cause of mortality worldwide. We conducted a genome-wide association study meta-analysis of 100,204 CRC cases and 154,587 controls of European and east Asian ancestry, identifying 205 independent risk associations, of which 50 were unreported. We performed integrative genomic, transcriptomic and methylomic analyses across large bowel mucosa and other tissues. Transcriptome- and methylome-wide association studies revealed an additional 53 risk associations. We identified 155 high-confidence effector genes functionally linked to CRC risk, many of which had no previously established role in CRC. These have multiple different functions and specifically indicate that variation in normal colorectal homeostasis, proliferation, cell adhesion, migration, immunity and microbial interactions determines CRC risk. Crosstissue analyses indicated that over a third of effector genes most probably act outside the colonic mucosa. Our findings provide insights into colorectal oncogenesis and highlight potential targets across tissues for new CRC treatment and chemoprevention strategies.
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37.
  • Gabrielsson, Erik, et al. (författare)
  • Autonomous Microcapillary Drug Delivery System Self-Powered by a Flexible Energy Harvester
  • 2021
  • Ingår i: Advanced Materials Technologies. - : Wiley-Blackwell. - 2365-709X. ; 6:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Implantable bioelectronic devices pave the way for novel biomedical applications operating at high spatiotemporal resolution, which is crucial for neural recording and stimulation, drug delivery, and brain-machine interfaces. Before successful long-term implantation and clinical applications, these devices face a number of challenges, such as mechanical and operational stability, biocompatibility, miniaturization, and powering. To address two of these crucial challenges-miniaturization and powering-the development and characterization of an electrophoretic drug delivery device, manufactured inside fused quartz fibers (outer diameter of 125 mu m), which is self-powered by a flexible piezoelectric energy harvester, are reported. The resulting device-the first integration of piezoelectric charging with "iontronic" delivery-exhibits a high delivery efficiency (number of neurotransmitters delivered per charges applied) and a direct correlation between the piezoelectric charging and the amount delivered (number of dynamic bends versus pmols delivered).
  •  
38.
  • Jelenkovic, Aline, et al. (författare)
  • Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age : A Study of the CODATwins Project
  • 2015
  • Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:5, s. 557-570
  • Tidskriftsartikel (refereegranskat)abstract
    • A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m(2) in childhood and adolescence and up to 0.2 kg/m(2) in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
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39.
  • Ju, Jin Sung, et al. (författare)
  • A novel 40-kDa protein containing six repeats of an epidermal growth factor-like domain functions as a pattern recognition protein for lipopolysaccharide
  • 2006
  • Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 177:3, s. 1838-1845
  • Tidskriftsartikel (refereegranskat)abstract
    • Determination of structures and functions of pattern recognition proteins are important for understanding pathogen recognition mechanisms in host defense and for elucidating the activation mechanism of innate immune reactions. In this study, a novel 40-kDa protein, named LPS recognition protein (LRP), was purified to homogeneity from the cell-free plasma of larvae of the large beetle, Holotrichia diomphalia. LRP exhibited agglutinating activities on Escherichia coli, but not on Staphylococcus aureus and Candida albicans. This E. coli-agglutinating activity was preferentially inhibited by the rough-type LPS with a complete core oligosaccharide. LRP consists of 317 aa residues and six repeats of an epidermal growth factor-like domain-Recombinant LRP expressed in a baculovirus system also showed E. coli agglutination activity in vitro and was able to neutralize LPS by inhibition of LPS-induced IL-6 production in mouse bone marrow mast cells. Furthermore, E. coli coated with the purified LRP were more rapidly cleared in the Holotrichia larvae than only E. coli, indicating that this protein participates in the clearance of E. coli in vivo. The three amino-terminal epidermal growth factor-like domains of LRP, but not the three carboxyl epidermal growth factor-like domains, are involved in the LPS-binding activity. Taken together, this LRP functions as a pattern recognition protein for LPS and plays a role as an innate immune protein.
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40.
  • Kang, Byung-Soo, et al. (författare)
  • The effect of calcium ion concentration on the bone response to oxidized titanium implants
  • 2012
  • Ingår i: Clinical Oral Implants Research. - Malden, USA : Wiley-Blackwell. - 0905-7161 .- 1600-0501. ; 23:6, s. 690-697
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: To investigate the effect of calcium concentration on the bone tissue response to Ca-incorporated titanium implants.Materials and methods: Two titanium surfaces containing 4.2% and 6.6% calcium were prepared using the micro-arc oxidation process. The implants were inserted in the tibia of nine New Zealand White rabbits. After 6 weeks of healing, the bone response to the implants was quantitatively compared by biomechanical and histomorphometrical measurements.Results: Ca 4.2% and Ca 6.6% containing implants revealed no distinctive differences in their qualitative surface chemistry; chemical bonding state of Ca in titanium oxide was mainly calcium titanates. No significant differences were observed between two implants in peak removal torque and shear strength comparisons (P>0.05). Histomorphometrical analyses presented no significant differences in bonemetal contact, bone area and newly formed bone measurements between two implants (P>0.05).Conclusions: From biomechanical and histomorphometrical measurements, the two calcium concentrations in this study did not differ significantly with respect to their influence on the bone tissue response. This similar bone response in rabbit tibiae may be explained by the similarity of the qualitative Ca chemistry in titanium surfaces.
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41.
  • Kang, Byung-Soo, et al. (författare)
  • XPS, AES and SEM analysis of recent dental implants
  • 2009
  • Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061. ; 5:6, s. 2222-2229
  • Tidskriftsartikel (refereegranskat)abstract
    • Today surface chemistry modifications of titanium implants have become a development strategy of dental implants. The present study investigated the chemistry and morphology of commercially available dental implants (Nobel biocare TiUnite, Astra AB OsseoSpeed, 3i Osseotite, ITI-SLA). X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES) were employed for the analysis of surface chemistry. The morphology was investigated by scanning electron microscopy (SEM). The present study demonstrated the major differences of surface properties, mainly dependent on the surface treatment used. The blasting and acid etching technique for the OsseoSpeed, Osseotite and SLA surfaces generally showed mainly TiO2, but a varying surface morphology. In contrast, the electrochemical oxidation process for TiUnite implants not only produces microporous surface (pore size: 0.53.0μm), but also changes surface chemistry due to incorporation of anions of the used electrolyte. As a result, TiUnite implants contain more than 7 at% of P in oxide layer and higher amounts of hydroxides compared to the other implants in XPS analysis. F in OsseoSpeed implants was detected at 0.3% before as well as after sputter cleaning.
  •  
42.
  • Lee, Dong Geon, et al. (författare)
  • Effect of Metal Electrodes on Aging-Induced Performance Recovery in Perovskite Solar Cells
  • 2019
  • Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:51, s. 48497-48504
  • Tidskriftsartikel (refereegranskat)abstract
    • For commercialization of perovskite solar cells (PSCs), it is important to substitute the alternative electrode for Au to decrease the unit cost. From the early stage, Ag exhibits a potential to be a good counter electrode in PSCs; however, there is an abnormal s-shaped J-V curve with the Ag electrode, and it is recovered as time passes. The perception of the aging-induced recovery process and refutation of the raised stability issues are required for commercial application of Ag electrodes. Herein, we compared the aging effect of PSCs with Ag and Au electrodes and found that only devices with Ag electrodes have a dramatical aging-induced recovery process. We observed the change of photoelectronic properties only in the devices with Ag electrodes as time passes, which mainly contributes to recovery of the s-shaped J-V curve. We verified the work function change of an aged Ag electrode and its mechanism by photoelectron spectroscopy analysis. By comparing the light stability under 1 sun intensity illumination, we can assure the practical stability of Ag electrodes in case of being encapsulated. This work suggests the profound understanding of the aging-induced recovery process of PSCs and the possibility of commercial application of Ag electrodes.
  •  
43.
  • Lee, Jun-Ho, et al. (författare)
  • Physisorption of DNA Nucleobases on h-BN and Graphene : vdW-Corrected DFT Calculations
  • 2013
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:26, s. 13435-13441
  • Tidskriftsartikel (refereegranskat)abstract
    • Using local, semilocal, and van der Waals energy-corrected density-functional theory (PBE + vdW) calculations, we present a comparative study of DNA nucleobases [guanine (G), adenine (A), thymine (T), and cytosine (C)] adsorbed on hexagonal boron nitride (h-BN) sheet and graphene. We find that, despite the very different electronic properties of BN sheet and graphene, the various nucleobase molecules have rather similar binding energies on the two types of sheets. The calculated binding energies of the four nucleobases using the local, semilocal, and PBE + vdW schemes are in the range of 0.54-0.75, 0.06-0.15, and 0.93-1.18 eV, respectively. In particular, the PBE + vdW scheme predicts not only a binding energy predominantly determined by vdW interactions between the base molecules and their substrates decreasing in the order of G > A > T >. C but also a very weak hybridization between the molecular levels of the nucleobases and the pi-states of the BN sheet or graphene. This physisorption of G, A, T, and C on the BN sheet (graphene) induces a small interfacial dipole, giving rise to an energy shift in the work function by 0.11 (0.22), 0.09 (0.15), -0.05 (0.01), and 0.06 (0.13) eV, respectively.
  •  
44.
  • Lee, Yun-Bin, et al. (författare)
  • Super-resolution proximity labeling reveals anti-viral protein network and its structural changes against SARS-CoV-2 viral proteins
  • 2023
  • Ingår i: Cell Reports. - : CELL PRESS. - 2211-1247. ; 42:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates in human cells by interacting with host factors following infection. To understand the virus and host interactome proximity, we introduce a super-resolution proximity labeling (SR-PL) method with a "plug-and-playable"PL enzyme, TurboID-GBP (GFP-binding nanobody protein), and we apply it for interactome mapping of SARS-CoV-2 ORF3a and mem-brane protein (M), which generates highly perturbed endoplasmic reticulum (ER) structures. Through SR-PL analysis of the biotinylated interactome, 224 and 272 peptides are robustly identified as ORF3a and M inter-actomes, respectively. Within the ORF3a interactome, RNF5 co-localizes with ORF3a and generates ubiquitin modifications of ORF3a that can be involved in protein degradation. We also observe that the SARS-CoV-2 infection rate is efficiently reduced by the overexpression of RNF5 in host cells. The interactome data ob-tained using the SR-PL method are presented at https://sarscov2.spatiomics.org. We hope that our method will contribute to revealing virus-host interactions of other viruses in an efficient manner.
  •  
45.
  • Mäkelä, Kristiina, et al. (författare)
  • Meeting the Challenges of Globalization in Order to Make a Difference : Implications for teams and team leadership
  • 2020
  • Ingår i: Research Handbook of Global Leadership. - Cheltenham : Edward Elgar Publishing. - 9781782545347 - 9781782545354 ; , s. 91-107
  • Bokkapitel (refereegranskat)abstract
    • In this chapter we suggest that globalization of businesses brings with it three new challenges that teams need to face. These include an increase in the number of internal and external stakeholders to manage; the need to interact across more and different types of boundaries; and an increasing necessity to integrate local responsiveness and global coordination. We focus on how these new globalization challenges impact teams in general and team leadership in particular, and how team leaders can make a difference by developing specific capabilities to address them.
  •  
46.
  • Park, So Yeon, et al. (författare)
  • Sustainable lead management in halide perovskite solar cells
  • 2020
  • Ingår i: Nature Sustainability. - : NATURE RESEARCH. - 2398-9629. ; 3:12
  • Tidskriftsartikel (refereegranskat)abstract
    • The most-efficient solar cells use Pb-based halide perovskites; however, their toxicity poses environmental and health risks. Here, the authors report an adsorbent that allows for sustainable Pb management in these devices. Despite the rapid development of perovskite solar cells (PSCs) toward commercialization, the toxic lead (Pb) ions in PSCs pose a potential threat to the environment, health and safety. Managing Pb via recycling represents a promising approach to mitigating its toxicity. However, managing Pb from commonly used organic solvents has been challenging due to the lack of suitable Pb adsorbents. Here, we report a new adsorbent for both separation and recovery of Pb from PSC pollutants. The synthesized iron-incorporated hydroxyapatite possesses a strongly negatively charged surface that improves electrostatic interaction through surface-charge delocalization, thus leading to enhanced Pb adsorption. We demonstrate the feasibility of a complete Pb management process, including the purification of Pb-containing non-aqueous solvents below 15 parts per 10(9), a level compliant with the standards of the US Environmental Protection Agency, as well as recycling of 99.97% of Pb ions by forming lead iodide.
  •  
47.
  • Proletov, Ian, et al. (författare)
  • Primary and secondary glomerulonephritides 1.
  • 2014
  • Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 29 Suppl 3:May, s. 186-200
  • Tidskriftsartikel (refereegranskat)
  •  
48.
  • Subramanian, Arunprabaharan, et al. (författare)
  • Trade-off between Zr Passivation and Sn Doping on Hematite Nanorod Photoanodes for Efficient Solar Water Oxidation : Effects of a ZrO2 Underlayer and FTO Deformation
  • 2016
  • Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:30, s. 19428-19437
  • Tidskriftsartikel (refereegranskat)abstract
    • Herein we report the influence of a ZrO2 underlayer on the PEC (photoelectrochemical) behavior of hematite nanorod photoanodes for efficient solar water splitting. Particular attention was given to the cathodic shift in onset potential and photocurrent enhancement. Akaganite (beta-FeOOH) nanorods were grown on ZrO2-coated FTO (fluorine-doped tin oxide) substrates. Sintering at 800 degrees C transformed akaganite to the hematite (alpha-Fe2O3) phase and induced Sn diffusion into the crystal structure of hematite nanorods from the FTO substrates and surface migration, shallow doping of Zr atoms from the ZrO2 underlayer. The ZrO2 underlayer-treated photoanode showed better water oxidation performance compared to the pristine (alpha-Fe2O3) photoanode. A cathodic shift in the onset potential and photocurrent enhancement was achieved by surface passivation and shallow doping of Zr from the ZrO2 underlayer, along with Sn doping from the FTO substrate to the crystal lattice of hematite nanorods. The Zr based hematite nanorod photoanode achieved 1 mA/cm(2) at 1.23 V-RHE with a low turn-on voltage of 0.80 V-RHE. Sn doping and Zr passivation, as well as shallow doping, were confirmed by XPS, I-ph, and M-S plot analyses. Electrochemical impedance spectroscopy revealed that the presence of a ZrO2 underlayer decreased the deformation of FTO substrate, improved electron transfer at the hematite/FTO interface and increased charge-transfer resistance at the electrolyte/hematite interface. This is the first systematic investigation of the effects of Zr passivation, shallow doping, and Sn doping on hematite nanorod photoanodes through application of a ZrO2 underlayer on the FTO substrate.
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