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1.
  • 2021
  • swepub:Mat__t
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2.
  • 2021
  • swepub:Mat__t
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3.
  • Bravo, L, et al. (author)
  • 2021
  • swepub:Mat__t
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4.
  • Tabiri, S, et al. (author)
  • 2021
  • swepub:Mat__t
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5.
  • Glasbey, JC, et al. (author)
  • 2021
  • swepub:Mat__t
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8.
  • Arndt, D. S., et al. (author)
  • STATE OF THE CLIMATE IN 2017
  • 2018
  • In: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 99:8, s. S1-S310
  • Research review (peer-reviewed)
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9.
  • Arndt, D. S., et al. (author)
  • State of the Climate in 2016
  • 2017
  • In: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 98:8, s. S1-S280
  • Journal article (peer-reviewed)abstract
    • In 2016, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-continued to increase and reach new record highs. The 3.5 +/- 0.1 ppm rise in global annual mean carbon dioxide from 2015 to 2016 was the largest annual increase observed in the 58-year measurement record. The annual global average carbon dioxide concentration at Earth's surface surpassed 400 ppm (402.9 +/- 0.1 ppm) for the first time in the modern atmospheric measurement record and in ice core records dating back as far as 800000 years. One of the strongest El Nino events since at least 1950 dissipated in spring, and a weak La Nina evolved later in the year. Owing at least in part to the combination of El Nino conditions early in the year and a long-term upward trend, Earth's surface observed record warmth for a third consecutive year, albeit by a much slimmer margin than by which that record was set in 2015. Above Earth's surface, the annual lower troposphere temperature was record high according to all datasets analyzed, while the lower stratospheric temperature was record low according to most of the in situ and satellite datasets. Several countries, including Mexico and India, reported record high annual temperatures while many others observed near-record highs. A week-long heat wave at the end of April over the northern and eastern Indian peninsula, with temperatures surpassing 44 degrees C, contributed to a water crisis for 330 million people and to 300 fatalities. In the Arctic the 2016 land surface temperature was 2.0 degrees C above the 1981-2010 average, breaking the previous record of 2007, 2011, and 2015 by 0.8 degrees C, representing a 3.5 degrees C increase since the record began in 1900. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 24 March, the sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, tying with 2015 at 7.2% below the 1981-2010 average. The September 2016 Arctic sea ice minimum extent tied with 2007 for the second lowest value on record, 33% lower than the 1981-2010 average. Arctic sea ice cover remains relatively young and thin, making it vulnerable to continued extensive melt. The mass of the Greenland Ice Sheet, which has the capacity to contribute similar to 7 m to sea level rise, reached a record low value. The onset of its surface melt was the second earliest, after 2012, in the 37-year satellite record. Sea surface temperature was record high at the global scale, surpassing the previous record of 2015 by about 0.01 degrees C. The global sea surface temperature trend for the 21st century-to-date of +0.162 degrees C decade(-1) is much higher than the longer term 1950-2016 trend of +0.100 degrees C decade(-1). Global annual mean sea level also reached a new record high, marking the sixth consecutive year of increase. Global annual ocean heat content saw a slight drop compared to the record high in 2015. Alpine glacier retreat continued around the globe, and preliminary data indicate that 2016 is the 37th consecutive year of negative annual mass balance. Across the Northern Hemisphere, snow cover for each month from February to June was among its four least extensive in the 47-year satellite record. Continuing a pattern below the surface, record high temperatures at 20-m depth were measured at all permafrost observatories on the North Slope of Alaska and at the Canadian observatory on northernmost Ellesmere Island. In the Antarctic, record low monthly surface pressures were broken at many stations, with the southern annular mode setting record high index values in March and June. Monthly high surface pressure records for August and November were set at several stations. During this period, record low daily and monthly sea ice extents were observed, with the November mean sea ice extent more than 5 standard deviations below the 1981-2010 average. These record low sea ice values contrast sharply with the record high values observed during 2012-14. Over the region, springtime Antarctic stratospheric ozone depletion was less severe relative to the 1991-2006 average, but ozone levels were still low compared to pre-1990 levels. Closer to the equator, 93 named tropical storms were observed during 2016, above the 1981-2010 average of 82, but fewer than the 101 storms recorded in 2015. Three basins-the North Atlantic, and eastern and western North Pacific-experienced above-normal activity in 2016. The Australian basin recorded its least active season since the beginning of the satellite era in 1970. Overall, four tropical cyclones reached the Saffir-Simpson category 5 intensity level. The strong El Nino at the beginning of the year that transitioned to a weak La Nina contributed to enhanced precipitation variability around the world. Wet conditions were observed throughout the year across southern South America, causing repeated heavy flooding in Argentina, Paraguay, and Uruguay. Wetter-than-usual conditions were also observed for eastern Europe and central Asia, alleviating the drought conditions of 2014 and 2015 in southern Russia. In the United States, California had its first wetter-than-average year since 2012, after being plagued by drought for several years. Even so, the area covered by drought in 2016 at the global scale was among the largest in the post-1950 record. For each month, at least 12% of land surfaces experienced severe drought conditions or worse, the longest such stretch in the record. In northeastern Brazil, drought conditions were observed for the fifth consecutive year, making this the longest drought on record in the region. Dry conditions were also observed in western Bolivia and Peru; it was Bolivia's worst drought in the past 25 years. In May, with abnormally warm and dry conditions already prevailing over western Canada for about a year, the human-induced Fort McMurray wildfire burned nearly 590000 hectares and became the costliest disaster in Canadian history, with $3 billion (U.S. dollars) in insured losses.
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10.
  • Blunden, Jessica, et al. (author)
  • State of the Climate in 2012
  • 2013
  • In: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 94:8, s. S1-S258
  • Journal article (peer-reviewed)abstract
    • For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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11.
  • Ades, M., et al. (author)
  • Global Climate : in State of the climate in 2019
  • 2020
  • In: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 101:8, s. S17-S127
  • Journal article (peer-reviewed)
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12.
  • Ades, M., et al. (author)
  • GLOBAL CLIMATE
  • 2020
  • In: BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY. - 0003-0007 .- 1520-0477. ; 101:8
  • Journal article (peer-reviewed)
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13.
  • Cirasuolo, M., et al. (author)
  • MOONS: the Multi-Object Optical and Near-infrared Spectrograph for the VLT
  • 2014
  • In: Ground-based and Airborne Instrumentation for Astronomy V. - : SPIE. - 1996-756X .- 0277-786X. ; 9147, s. 91470-91470
  • Conference paper (peer-reviewed)abstract
    • MOONS (the Multi-Object Optical and Near-infrared Spectrograph) has been selected by ESO as a third-generation instrument for the Very Large Telescope (VLT). The light grasp of the large collecting area offered by the VLT (8.2m diameter), combined with the large multiplex and wavelength coverage (optical to near-IR: 0.8 -1.8 mu m) of MOONS will provide the European astronomical community with a powerful, unique instrument able to pioneer a wide range of Galactic, extragalactic and cosmological studies, and it will provide crucial follow-up for major facilities such as Gaia, VISTA, Euclid and LSST. MOONS has the observational power needed to unveil galaxy formation and evolution over the entire history of the Universe, from stars in our Milky Way, through the redshift desert, and up to the epoch of very first galaxies and reionization of the Universe at redshifts of z > 8-9, just a few million years after the Big Bang. From five years of observations MOONS will provide high-quality spectra for > 3M stars in our Galaxy and the Local Group, and for 1-2M galaxies at z > 1 (for an SDSS-like survey), promising to revolutionize our understanding of the Universe. The baseline design consists of similar to 1000 fibres, deployable over a field-of-view of similar to 500 arcmin(2), the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8 -1.8 mu m with two spectral resolving powers: in the medium-resolution mode (R similar to 4,000-6,000) the entire wavelength range is observed simultaneously, while the high-resolution mode will cover three selected sub-regions simultaneously: one region with R similar to 8,000 near the Ca II triplet to measure stellar radial velocities, and two regions at R similar to 20,000 (one in each of the J- and H-bands), for precision measurements of chemical abundances.
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14.
  • Menkveld, Albert J., et al. (author)
  • Nonstandard Errors
  • 2024
  • In: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
  • Journal article (peer-reviewed)abstract
    • In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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15.
  • Barillot, T., et al. (author)
  • Correlation-Driven Transient Hole Dynamics Resolved in Space and Time in the Isopropanol Molecule
  • 2021
  • In: Physical Review X. - : American Physical Society. - 2160-3308. ; 11:3
  • Journal article (peer-reviewed)abstract
    • The possibility of suddenly ionized molecules undergoing extremely fast electron hole (or hole) dynamics prior to significant structural change was first recognized more than 20 years ago and termed charge migration. The accurate probing of ultrafast electron hole dynamics requires measurements that have both sufficient temporal resolution and can detect the localization of a specific hole within the molecule. We report an investigation of the dynamics of inner valence hole states in isopropanol where we use an x-ray pump-x-ray probe experiment, with site and state-specific probing of a transient hole state localized near the oxygen atom in the molecule, together with an ab initio theoretical treatment. We record the signature of transient hole dynamics and make the first tentative observation of dynamics driven by frustrated Auger-Meitner transitions. We verify that the effective hole lifetime is consistent with our theoretical prediction. This state-specific measurement paves the way to widespread application for observations of transient hole dynamics localized in space and time in molecules and thus to charge transfer phenomena that are fundamental in chemical and material physics.
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16.
  • Blunden, Jessica, et al. (author)
  • State of the climate in 2013
  • 2014
  • In: Bulletin of the American Meteorological Society. - 0003-0007. ; 95
  • Journal article (peer-reviewed)abstract
    • © 2014, American Meteorological Society. All rights reserved. In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earth’s surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series.
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17.
  • Sanchez-Gonzalez, A., et al. (author)
  • Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning
  • 2017
  • In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
  • Journal article (peer-reviewed)abstract
    • Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.
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18.
  • Sanchez-Gonzalez, A., et al. (author)
  • Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL
  • 2015
  • In: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 48:23
  • Journal article (peer-reviewed)abstract
    • We report the first measurement of the near oxygen K-edge auger spectrum of the glycine molecule. Our work employed an x-ray free electron laser as the photon source operated with input photon energies tunable between 527 and 547 eV. Complete electron spectra were recorded at each photon energy in the tuning range, revealing resonant and non-resonant auger structures. Finally ab initio theoretical predictions are compared with the measured above the edge auger spectrum and an assignment of auger decay channels is performed.
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19.
  • Al-Khalili, A, et al. (author)
  • Dissociative recombination cross section and branching ratios of protonated dimethyl disulfide and N-methylacetamide
  • 2004
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:12, s. 5700-5708
  • Journal article (peer-reviewed)abstract
    • Dimethyl disulfide (DMDS) and N-methylacetamide are two first choice model systems that represent the disulfide bridge bonding and the peptide bonding in proteins. These molecules are therefore suitable for investigation of the mechanisms involved when proteins fragment under electron capture dissociation (ECD). The dissociative recombination cross sections for both protonated DMDS and protonated N-methylacetamide were determined at electron energies ranging from 0.001 to 0.3 eV. Also, the branching ratios at 0 eV center-of-mass collision energy were determined. The present results give support for the indirect mechanism of ECD, where free hydrogen atoms produced in the initial fragmentation step induce further decomposition. We suggest that both indirect and direct dissociations play a role in ECD.
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21.
  • Therriault, J., et al. (author)
  • Equivalence of plasma p-tau217 with cerebrospinal fluid in the diagnosis of Alzheimer's disease
  • 2023
  • In: Alzheimers & Dementia. - 1552-5260. ; 19:11, s. 4967-4977
  • Journal article (peer-reviewed)abstract
    • INTRODUCTION: Plasma biomarkers are promising tools for Alzheimer's disease (AD) diagnosis, but comparisons with more established biomarkers are needed.METHODS: We assessed the diagnostic performance of p-tau(181), p-tau(217), and p-tau(231) in plasma and CSF in 174 individuals evaluated by dementia specialists and assessed with amyloid-PET and tau-PET. Receiver operating characteristic (ROC) analyses assessed the performance of plasma and CSF biomarkers to identify amyloid-PET and tau-PET positivity.RESULTS: Plasma p-tau biomarkers had lower dynamic ranges and effect sizes compared to CSF p-tau. Plasma p-tau(181) (AUC = 76%) and p-tau(231) (AUC = 82%) assessments performed inferior to CSF p-tau(181) (AUC = 87%) and p-tau(231) (AUC = 95%) for amyloid-PET positivity. However, plasma p-tau(217) (AUC = 91%) had diagnostic performance indistinguishable from CSF (AUC = 94%) for amyloid-PET positivity.DISCUSSION: Plasma and CSF p-tau(217) had equivalent diagnostic performance for biomarker-defined AD. Our results suggest that plasma p-tau(217) may help reduce the need for invasive lumbar punctures without compromising accuracy in the identification of AD.
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25.
  • Wise, L M, et al. (author)
  • Vascular endothelial growth factor (VEGF)-like protein from orf virus NZ2 binds to VEGFR2 and neuropilin-1.
  • 1999
  • In: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 96:6
  • Journal article (peer-reviewed)abstract
    • Orf virus, a member of the poxvirus family, produces a pustular dermatitis in sheep, goats, and humans. The lesions induced after infection with orf virus show extensive proliferation of vascular endothelial cells, dilation of blood vessels and dermal swelling. An explanation for the nature of these lesions may lie in the discovery that orf virus encodes an apparent homolog of the mammalian vascular endothelial growth factor (VEGF) family of molecules. These molecules mediate endothelial cell proliferation, vascular permeability, angiogenesis, and lymphangiogenesis via the endothelial cell receptors VEGFR-1 (Flt1), VEGFR-2 (KDR/Flk1), and VEGFR-3 (Flt4). The VEGF-like protein of orf virus strain NZ2 (ORFV2-VEGF) is most closely related in primary structure to VEGF. In this study we examined the biological activities and receptor specificity of the ORFV2-VEGF protein. ORFV2-VEGF was found to be a disulfide-linked homodimer with a subunit of approximately 25 kDa. ORFV2-VEGF showed mitogenic activity on bovine aortic and human microvascular endothelial cells and induced vascular permeability. ORFV2-VEGF was found to bind and induce autophosphorylation of VEGFR-2 and was unable to bind or activate VEGFR-1 and VEGFR-3, but bound the newly identified VEGF165 receptor neuropilin-1. These results indicate that, from a functional viewpoint, ORFV2-VEGF is indeed a member of the VEGF family of molecules, but is unique, however, in that it utilizes only VEGFR-2 and neuropilin-1.
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26.
  • Achen, M G, et al. (author)
  • Vascular endothelial growth factor D (VEGF-D) is a ligand for the tyrosine kinases VEGF receptor 2 (Flk1) and VEGF receptor 3 (Flt4).
  • 1998
  • In: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 95:2
  • Journal article (peer-reviewed)abstract
    • We have identified a member of the VEGF family by computer-based homology searching and have designated it VEGF-D. VEGF-D is most closely related to VEGF-C by virtue of the presence of N- and C-terminal extensions that are not found in other VEGF family members. In adult human tissues, VEGF-D mRNA is most abundant in heart, lung, skeletal muscle, colon, and small intestine. Analyses of VEGF-D receptor specificity revealed that VEGF-D is a ligand for both VEGF receptors (VEGFRs) VEGFR-2 (Flk1) and VEGFR-3 (Flt4) and can activate these receptors. However. VEGF-D does not bind to VEGFR-1. Expression of a truncated derivative of VEGF-D demonstrated that the receptor-binding capacities reside in the portion of the molecule that is most closely related in primary structure to other VEGF family members and that corresponds to the mature form of VEGF-C. In addition, VEGF-D is a mitogen for endothelial cells. The structural and functional similarities between VEGF-D and VEGF-C define a subfamily of the VEGFs.
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27.
  • Chen, S. C., et al. (author)
  • Development of A Minimum Dataset for the Monitoring of Recombinant Human Growth Hormone (rhGH) Therapy Use in Children with Growth Hormone Deficiency (GHD) - A GloBE-Reg Initiative
  • 2023
  • In: Hormone Research in Paediatrics. - 1663-2818 .- 1663-2826.
  • Journal article (peer-reviewed)abstract
    • Introduction Although there are some recommendations in the literature on the assessments that should be performed in children on recombinant human growth hormone (rhGH) therapy, the level of consensus on these measurements is not clear. The objective of the current study was to identify the minimum dataset (MDS) that could be measured in a routine clinical setting across the world, aiming to minimise burden on clinicians and improve quality of data collection. Methods This study was undertaken by the GH Scientific Study Group (SSG) in GloBE-Reg, a new project that has developed a common registry platform that can support long-term safety and effectiveness studies of drugs. Twelve clinical experts from 7 international endocrine organisations identified by the GloBE-Reg Steering Committee, 2 patient representatives and representatives from 2 pharmaceutical companies with previous GH registry expertise collaborated to develop this recommendation. A comprehensive list of data fields routinely collected by each of the clinical and industry experts for children with GHD was compiled. Each member was asked to determine the: (1) Importance of the data field and (2) Ease of data collection. Data fields that achieved 70% consensus in terms of importance qualified for the MDS, provided <50% deemed the item difficult to collect.Results A total of 246 items were compiled and 27 removed due to redundancies, with 219 items subjected to the grading system. Of the 219 items, 111 achieved at least 70% consensus as important data to collect when monitoring children with GH deficiency (GHD) on rhGH treatment. Sixty-nine of the 219 items were deemed easy to collect. Combining the criteria of importance and ease of data collection, 63 met the criteria for the MDS. Several anomalies to the MDS rule were identified and highlighted for discussion, including whether the patients were involved in current or previous clinical trials, need for HbA1c monitoring, other past medical history, and adherence, enabling formulation of the final MDS recommendation of 43 items; 20 to be completed once, 14 every 6 months and 9 every 12 months.Conclusion In summary, this exercise performed through the GloBE-Reg initiative provides a recommendation of the minimum dataset requirement, collected through real-world data, for the monitoring of safety and effectiveness of rhGH in children with GHD, both for the current daily preparations and the newer long-acting growth hormone.
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29.
  • Rohringer, N., et al. (author)
  • Stimulated X-Ray Raman Scattering with Free-Electron Laser Sources
  • 2016
  • In: X-Ray Lasers 2014. - Cham : Springer. - 0930-8989. - 9783319195216 - 9783319195209 ; , s. 201-207
  • Book chapter (peer-reviewed)abstract
    • Stimulated electronic x-ray Raman scattering is the building block for several proposed x-ray pump probe techniques, that would allow the study of electron dynamics at unprecedented timescales.We present high spectral resolution data on stimulated electronic x-ray Raman scattering in a gas sample of neon using a self-amplified spontaneous emission x-ray free-electron laser. Despite the limited spectral coherence and broad bandwidth of these sources, high-resolution spectra can be obtained by statistical methods, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and the results of a recent experiment in CO are discussed.
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33.
  • Allum, F., et al. (author)
  • A localized view on molecular dissociation via electron-ion partial covariance
  • 2022
  • In: Communications Chemistry. - : Springer Science and Business Media LLC. - 2399-3669. ; 5:1
  • Journal article (peer-reviewed)abstract
    • Inner-shell photoelectron spectroscopy provides an element-specific probe of molecular structure, as core-electron binding energies are sensitive to the chemical environment. Short-wavelength femtosecond light sources, such as Free-Electron Lasers (FELs), even enable time-resolved site-specific investigations of molecular photochemistry. Here, we study the ultraviolet photodissociation of the prototypical chiral molecule 1-iodo-2-methylbutane, probed by extreme-ultraviolet (XUV) pulses from the Free-electron LASer in Hamburg (FLASH) through the ultrafast evolution of the iodine 4d binding energy. Methodologically, we employ electron-ion partial covariance imaging as a technique to isolate otherwise elusive features in a two-dimensional photoelectron spectrum arising from different photofragmentation pathways. The experimental and theoretical results for the time-resolved electron spectra of the 4d(3/2) and 4d(5/2) atomic and molecular levels that are disentangled by this method provide a key step towards studying structural and chemical changes from a specific spectator site. Coincidence experiments at free-electron lasers enable time resolved site-specific investigations of molecular photochemistry at high signal rates, but isolating individual dissociation processes still poses a considerable technical challenge. Here, the authors use electron-ion partial covariance imaging to isolate otherwise elusive chemical shifts in UV-induced photofragmentation pathways of the prototypical chiral molecule 1-iodo-2-methylbutane.
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34.
  • Barrio, Isabel C., et al. (author)
  • Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome
  • 2017
  • In: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 40:11, s. 2265-2278
  • Journal article (peer-reviewed)abstract
    • Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6-7% over the current levels with a 1 degrees C increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.
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35.
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36.
  • Carrick, Richard T., et al. (author)
  • Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe
  • 2024
  • In: European Heart Journal. - : OXFORD UNIV PRESS. - 0195-668X .- 1522-9645.
  • Journal article (peer-reviewed)abstract
    • Background and Aims Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.Methods This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.Results One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.Conclusions North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.
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37.
  • Colombo, GI, et al. (author)
  • The Association between HDL-C and Subclinical Atherosclerosis Depends on CETP Plasma Concentration: Insights from the IMPROVE Study
  • 2021
  • In: Biomedicines. - : MDPI AG. - 2227-9059. ; 9:3
  • Journal article (peer-reviewed)abstract
    • The impact of cholesteryl ester transfer protein (CETP) on atherosclerosis is highly debated. This study aimed to investigate the associations between plasma CETP or CETP genotypes and carotid intima-media thickness (cIMT) and the influence of high-density lipoprotein cholesterol (HDL-C) on these associations. Plasma CETP and HDL-C concentrations were measured in 552 subjects free of any pharmacological treatment from the IMPROVE cohort, which includes 3711 European subjects at high cardiovascular risk. CETP single-nucleotide polymorphisms (SNPs) and cIMT measures (cIMTmax; cIMTmean–max of bifurcations, common and internal carotids; plaque-free common carotid [PF CC]-IMTmean) were available for the full cohort. In drug-free subjects, plasma CETP correlated with HDL-C levels (r = 0.19, p < 0.0001), but not with cIMT variables. When stratified according to HDL-C quartiles, CETP positively correlated with cIMTmax and cIMTmean–max, but not with PF CC-IMTmean, in the top HDL-C quartile only. Positive associations between the CETP concentration and cIMTmax or cIMTmean–max were found in the top HDL-C quartile, whereas HDL-C levels were negatively correlated with cIMTmax and cIMTmean–max when the CETP concentration was below the median (HDL-C × CETP interaction, p = 0.001 and p = 0.003 for cIMTmax and cIMTmean–max, respectively). In the full cohort, three CETP SNPs (rs34760410, rs12920974, rs12708968) were positively associated with cIMTmax. rs12444708 exhibited a significant interaction with HDL-C levels in the prediction of cIMTmax. In conclusion, a significant interplay was found between plasma CETP and/or CETP genotype and HDL-C in the prediction of carotid plaque thickness, as indexed by cIMTmax. This suggests that the association of HDL-C with carotid atherosclerosis is CETP-dependent.
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38.
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39.
  • Dubrovinsky, Leonid, et al. (author)
  • Materials synthesis at terapascal static pressures
  • 2022
  • In: Nature. - London, United Kingdom : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 605:7909, s. 274-278
  • Journal article (peer-reviewed)abstract
    • Theoretical modelling predicts very unusual structures and properties of materials at extreme pressure and temperature conditions(1,2). Hitherto, their synthesis and investigation above 200 gigapascals have been hindered both by the technical complexity of ultrahigh-pressure experiments and by the absence of relevant in situ methods of materials analysis. Here we report on a methodology developed to enable experiments at static compression in the terapascal regime with laser heating. We apply this method to realize pressures of about 600 and 900 gigapascals in a laser-heated double-stage diamond anvil cell(3), producing a rhenium-nitrogen alloy and achieving the synthesis of rhenium nitride Re7N3-which, as our theoretical analysis shows, is only stable under extreme compression. Full chemical and structural characterization of the materials, realized using synchrotron single-crystal X-ray diffraction on microcrystals in situ, demonstrates the capabilities of the methodology to extend high-pressure crystallography to the terapascal regime.
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40.
  • Martin, Nicolas F., et al. (author)
  • The Pristine survey - XVI. The metallicity of 26 stellar streams around the Milky Way detected with the STREAMFINDER in Gaia EDR3
  • 2022
  • In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 516:4, s. 5331-5354
  • Journal article (peer-reviewed)abstract
    • We use the photometric metallicities provided by the panoramic Pristine survey to study the veracity and derive the metallicities of the numerous stellar streams found by the application of the STREAMFINDER algorithm to the Gaia Early Data Release 3 data. All 26 streams present in Pristine show a clear metallicity distribution function, which provides an independent check of the reality of these structures, supporting the reliability of STREAMFINDER in finding streams and the power of Pristine to measure precise metallicities. We further present six candidate structures with coherent phase-space and metallicity signals that are very likely streams. The majority of studied streams are very metal-poor (14 structures with [Fe/H] < −2.0) and include three systems with [Fe/H] < −2.9 (C-11, C-19, and C-20). These streams could be the closest debris of low-luminosity dwarf galaxies or may have originated from globular clusters of significantly lower metallicity than any known current Milky Way globular cluster. Our study shows that the promise of the Gaia data for Galactic Archeology studies can be substantially strengthened by quality photometric metallicities, allowing us to peer back into the earliest epochs of the formation of our Galaxy and its stellar halo constituents.
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41.
  • Ramos-Casals, Manuel, et al. (author)
  • EULAR recommendations for the management of Sjögren's syndrome with topical and systemic therapies.
  • 2020
  • In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 79:1, s. 3-18
  • Journal article (peer-reviewed)abstract
    • The therapeutic management of Sjögren syndrome (SjS) has not changed substantially in recent decades: treatment decisions remain challenging in clinical practice, without a specific therapeutic target beyond the relief of symptoms as the most important goal. In view of this scenario, the European League Against Rheumatism (EULAR) promoted and supported an international collaborative study (EULAR SS Task Force) aimed at developing the first EULAR evidence and consensus-based recommendations for the management of patients with SjS with topical and systemic medications. The aim was to develop a rational therapeutic approach to SjS patients useful for healthcare professionals, physicians undergoing specialist training, medical students, the pharmaceutical industry and drug regulatory organisations following the 2014 EULAR standardised operating procedures. The Task Force (TF) included specialists in rheumatology, internal medicine, oral health, ophthalmology, gynaecology, dermatology and epidemiology, statisticians, general practitioners, nurses and patient representatives from 30 countries of the 5 continents. Evidence was collected from studies including primary SjS patients fulfilling the 2002/2016 criteria; when no evidence was available, evidence from studies including associated SjS or patients fulfilling previous sets of criteria was considered and extrapolated. The TF endorsed the presentation of general principles for the management of patients with SjS as three overarching, general consensus-based recommendations and 12 specific recommendations that form a logical sequence, starting with the management of the central triplet of symptoms (dryness, fatigue and pain) followed by the management of systemic disease. The recommendations address the use of topical oral (saliva substitutes) and ocular (artificial tear drops, topical non-steroidal anti-inflammatory drugs, topical corticosteroids, topical CyA, serum tear drops) therapies, oral muscarinic agonists (pilocarpine, cevimeline), hydroxychloroquine, oral glucocorticoids, synthetic immunosuppressive agents (cyclophosphamide, azathioprine, methotrexate, leflunomide and mycophenolate), and biological therapies (rituximab, abatacept and belimumab). For each recommendation, levels of evidence (mostly modest) and TF agreement (mostly very high) are provided. The 2019 EULAR recommendations are based on the evidence collected in the last 16 years in the management of primary 2002 SjS patients and on discussions between a large and broadly international TF. The recommendations synthesise current thinking on SjS treatment in a set of overarching principles and recommendations. We hope that the current recommendations will be broadly applied in clinical practice and/or serve as a template for national societies to develop local recommendations.
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42.
  • Retamozo, Soledad, et al. (author)
  • Therapeutic Recommendations for the Management of Older Adult Patients with Sjögren’s Syndrome
  • 2021
  • In: Drugs & Aging. - : Springer Science and Business Media LLC. - 1170-229X .- 1179-1969. ; 38:4, s. 265-284
  • Journal article (peer-reviewed)abstract
    • Primary Sjögren’s syndrome (SjS) is a systemic autoimmune disease most commonly diagnosed in middle-aged women. Although the disease can occur at all ages, it is diagnosed between 30 and 60 years of age in two-thirds of patients. In more than 20% of cases, the people are older than 65 years. In this review, we focus on the therapeutic management of primary SjS in older patients, following the recently published 2020 European League Against Rheumatism (EULAR) recommendations for the management of the disease with topical and systemic therapies. These recommendations are applicable to all patients with primary SjS regardless of age at diagnosis, although the therapeutic management in older patients requires additional considerations. Older patients are more likely to have pulmonary, liver, kidney, or heart-related comorbidities (even cognitive disturbances); caution is required when most drugs are used, including muscarinic agents, systemic corticosteroids and synthetic immunosuppressants. It is also important to monitor the use of eye drops containing steroids due to the increased risk of developing cataracts, a frequent ocular complication in the older population. In contrast, the majority of drugs that can be used topically (pilocarpine rinses, eye drops containing topical non-steroidal anti-inflammatory drugs (NSAIDs) or cyclosporine A, topical dermal formulations of NSAIDs) have shown an acceptable safety profile in older patients, as well as rituximab. A rigorous evaluation of the medical history of older patients is essential when drugs included in the EULAR guidelines are prescribed, with special attention to factors frequently related to ageing, such as polypharmacy, the existence of organ-specific comorbidities, or the enhanced susceptibility to infections.
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43.
  • Schio, L., et al. (author)
  • A Study of H2O2 with Threshold Photoelectron Spectroscopy (TPES) and Electronic Structure Calculations: Redetermination of the First Adiabatic Ionization Energy (AIE)
  • 2016
  • In: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 120:27, s. 5220-5229
  • Journal article (peer-reviewed)abstract
    • In this work, hydrogen peroxide has been studied with threshold photoelectron (TPE) spectroscopy and photoelectron (PE) spectroscopy. The TPE spectrum has been recorded in the 10.0-21.0 eV ionization energy region, and the PE spectrum has been recorded at 21.22 eV photon energy. Five bands have been observed which have been assigned on the basis of UCCSD(T)-F12/VQZ-F12 and IP-EOM CCSD calculations. Vibrational structure has only been resolved in the TPE spectrum of the first band, associated with the (X) over tilde (2)Bg H2O2+ <- (X) over tilde (1)A H2O2 ionization, on its low energy side. This structure is assigned with the help of harmonic Franck-Condon factor calculations that use the UCCSD(T)-F12a/VQZ-F12 computed adiabatic ionization energy (AIE), and UCCSD(T)-F12a/VQZ-F12 computed equilibrium geometric parameters and harmonic vibrational frequencies for the H2O2 (X) over tilde (1)A state and the H2O2 (X) over tilde (2)Bg state. These calculations show that the main vibrational structure on the leading edge of the first TPE band is in the O-O stretching mode (omega(3)) and the HOOH deformation mode (omega(4)), and comparison of the simulated spectrum to the experimental spectrum gives the first AIE of H2O2 as (10.685 +/- 0.005) eV and omega(4) = (850 +/- 30) and omega(3) = (1340 +/- 30) cm(-1) in the (X) over tilde (2)Bg state of H2O2+. Contributions from ionization of vibrationally excited levels in the torsion mode have been identified in the TPE spectrum of the first band and the need for a vibrationally resolved TPE spectrum from vibrationally cooled molecules, as well as higher level Franck-Condon factors than performed in this work, is emphasized.
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44.
  • Squibb, Richard J., et al. (author)
  • Acetylacetone photodynamics at a seeded free-electron laser
  • 2018
  • In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
  • Journal article (peer-reviewed)abstract
    • Thefirst steps in photochemical processes, such as photosynthesis or animal vision, involvechanges in electronic and geometric structure on extremely short time scales. Time-resolvedphotoelectron spectroscopy is a natural way to measure such changes, but has been hinderedhitherto by limitations of available pulsed light sources in the vacuum-ultraviolet and soft X-ray spectral region, which have insufficient resolution in time and energy simultaneously. Theunique combination of intensity, energy resolution, and femtosecond pulse duration of theFERMI-seeded free-electron laser can now provide exceptionally detailed information onphotoexcitation–deexcitation and fragmentation in pump-probe experiments on the 50-femtosecond time scale. For the prototypical system acetylacetone we report here electronspectra measured as a function of time delay with enough spectral and time resolution tofollow several photoexcited species through well-characterized individual steps, interpretedusing state-of-the-art static and dynamics calculations. These results open the way forinvestigations of photochemical processes in unprecedented detail.
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45.
  • Therriault, Joseph, et al. (author)
  • Comparison of immunoassay- with mass spectrometry-derived p-tau quantification for the detection of Alzheimer’s disease pathology
  • 2024
  • In: Molecular Neurodegeneration. - 1750-1326. ; 19:1
  • Journal article (peer-reviewed)abstract
    • Background: Antibody-based immunoassays have enabled quantification of very low concentrations of phosphorylated tau (p-tau) protein forms in cerebrospinal fluid (CSF), aiding in the diagnosis of AD. Mass spectrometry enables absolute quantification of multiple p-tau variants within a single run. The goal of this study was to compare the performance of mass spectrometry assessments of p-tau181, p-tau217 and p-tau231 with established immunoassay techniques. Methods: We measured p-tau181, p-tau217 and p-tau231 concentrations in CSF from 173 participants from the TRIAD cohort and 394 participants from the BioFINDER-2 cohort using both mass spectrometry and immunoassay methods. All subjects were clinically evaluated by dementia specialists and had amyloid-PET and tau-PET assessments. Bland–Altman analyses evaluated the agreement between immunoassay and mass spectrometry p-tau181, p-tau217 and p-tau231. P-tau associations with amyloid-PET and tau-PET uptake were also compared. Receiver Operating Characteristic (ROC) analyses compared the performance of mass spectrometry and immunoassays p-tau concentrations to identify amyloid-PET positivity. Results: Mass spectrometry and immunoassays of p-tau217 were highly comparable in terms of diagnostic performance, between-group effect sizes and associations with PET biomarkers. In contrast, p-tau181 and p-tau231 concentrations measured using antibody-free mass spectrometry had lower performance compared with immunoassays. Conclusions: Our results suggest that while similar overall, immunoassay-based p-tau biomarkers are slightly superior to antibody-free mass spectrometry-based p-tau biomarkers. Future work is needed to determine whether the potential to evaluate multiple biomarkers within a single run offsets the slightly lower performance of antibody-free mass spectrometry-based p-tau quantification.
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46.
  • Therriault, J., et al. (author)
  • Determining Amyloid-β Positivity Using 18F-AZD4694 PET Imaging
  • 2021
  • In: Journal of nuclear medicine : official publication, Society of Nuclear Medicine. - : Society of Nuclear Medicine. - 1535-5667. ; 62:2, s. 247-252
  • Journal article (peer-reviewed)abstract
    • Amyloid-β deposition into plaques is a pathologic hallmark of Alzheimer disease appearing years before the onset of symptoms. Although cerebral amyloid-β deposition occurs on a continuum, dichotomization into positive and negative groups has advantages for diagnosis, clinical management, and population enrichment for clinical trials. 18F-AZD4694 (also known as 18F-NAV4694) is an amyloid-β imaging ligand with high affinity for amyloid-β plaques. Despite being used in multiple academic centers, no studies have assessed a quantitative cutoff for amyloid-β positivity using 18F-AZD4694 PET. Methods: We assessed 176 individuals [young adults (n = 22), cognitively unimpaired elderly (n = 89), and cognitively impaired (n = 65)] who underwent amyloid-β PET with 18F-AZD4694, lumbar puncture, structural MRI, and genotyping for APOEε418F-AZD4694 values were normalized using the cerebellar gray matter as a reference region. We compared 5 methods for deriving a quantitative threshold for 18F-AZD4694 PET positivity: comparison with young-control SUV ratios (SUVRs), receiver-operating-characteristic (ROC) curves based on clinical classification of cognitively unimpaired elderly versus Alzheimer disease dementia, ROC curves based on visual Aβ-positive/Aβ-negative classification, gaussian mixture modeling, and comparison with cerebrospinal fluid measures of amyloid-β, specifically the Aβ42/Aβ40 ratio. Results: We observed good convergence among the 4 methods: ROC curves based on visual classification (optimal cut point, 1.55 SUVR), ROC curves based on clinical classification (optimal cut point, 1.56 SUVR) gaussian mixture modeling (optimal cut point, 1.55 SUVR), and comparison with cerebrospinal fluid measures of amyloid-β (optimal cut point, 1.51 SUVR). Means and 2 SDs from young controls resulted in a lower threshold (1.33 SUVR) that did not agree with the other methods and labeled most elderly individuals as Aβ-positive. Conclusion: Good convergence was obtained among several methods for determining an optimal cutoff for 18F-AZD4694 PET positivity. Despite conceptual and analytic idiosyncrasies linked with dichotomization of continuous variables, an 18F-AZD4694 threshold of 1.55 SUVR had reliable discriminative accuracy. Although clinical use of amyloid PET is currently by visual inspection of scans, quantitative thresholds may be helpful to arbitrate disagreement among raters or in borderline cases. © 2021 by the Society of Nuclear Medicine and Molecular Imaging.
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47.
  • Tom, Brian A., et al. (author)
  • Dissociative recombination of highly enriched para-H-3(+)
  • 2009
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 130:3, s. 31101-
  • Journal article (peer-reviewed)abstract
    • The determination of the dissociative recombination rate coefficient of H-3(+) has had a turbulent history, but both experiment and theory have recently converged to a common value. Despite this convergence, it has not been clear if there should be a difference between the rate coefficients for ortho-H-3(+) and para-H-3(+). A difference has been predicted theoretically and could conceivably impact the ortho:para ratio of H-3(+) in the diffuse interstellar medium, where H-3(+) has been widely observed. We present the results of an experiment at the CRYRING ion storage ring in which we investigated the dissociative recombination of highly enriched (similar to 83.6%) para-H-3(+) using a supersonic expansion source that produced ions with T-rot similar to 60-100 K. We observed an increase in the low energy recombination rate coefficient of the enriched para-H-3(+) by a factor of similar to 1.25 in comparison to H-3(+) produced from normal H-2 (ortho:para=3:1). The ratio of the rate coefficients of pure para-H-3(+) to that of pure ortho-H-3(+) is inferred to be similar to 2 at low collision energies; the corresponding ratio of the thermal rate coefficients is similar to 1.5 at electron temperatures from 60 to 1000 K. We conclude that this difference is unlikely to have an impact on the interstellar ortho:para ratio of H-3(+).
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48.
  • Travnikova, O., et al. (author)
  • Photochemical Ring-Opening Reaction of 1,3-Cyclohexadiene: the True Reactive State
  • 2022
  • In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:48, s. 21878-21886
  • Journal article (peer-reviewed)abstract
    • The photochemically induced ring-opening isomeriza-tion reaction of 1,3-cyclohexadiene to 1,3,5-hexatriene is a textbook example of a pericyclic reaction and has been amply investigated with advanced spectroscopic techniques. The main open question has been the identification of the single reactive state which drives the process. The generally accepted description of the isomerization pathway starts with a valence excitation to the lowest lying bright state, followed by a passage through a conical intersection to the lowest lying doubly excited state, and finally a branching between either the return to the ground state of the cyclic molecule or the actual ring-opening reaction leading to the open-chain isomer. Here, in a joint experimental and computational effort, we demonstrate that the evolution of the excitation-deexcitation process is much more complex than that usually described. In particular, we show that an initially high-lying electronic state smoothly decreasing in energy along the reaction path plays a key role in the ring-opening reaction.
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