ALBERT

Description: Observation of the 1S–2S transition in trapped antihydrogen Nature 541, 7638 (2017). doi:10.1038/nature21040 Authors: M. Ahmadi, B. X. R. Alves, C. J. Baker, W. Bertsche, E. Butler, A. Capra, C. Carruth, C. L. Cesar, M. Charlton, S. Cohen, R. Collister, S. Eriksson, A. Evans, N. Evetts, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, A. Ishida, M. A. Johnson, S. A. Jones, S. Jonsell, L. Kurchaninov, N. Madsen, M. Mathers, D. Maxwell, J. T. K. McKenna, S. Menary, J. M. Michan, T. Momose, J. J. Munich, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, R. L. Sacramento, M. Sameed, E. Sarid, D. M. Silveira, S. Stracka, G. Stutter, C. So, T. D. Tharp, J. E. Thompson, R. I. Thompson, D. P. van der Werf & J. S. Wurtele The spectrum of the hydrogen atom has played a central part in fundamental physics over the past 200 years. Historical examples of its importance include the wavelength measurements of absorption lines in the solar spectrum by Fraunhofer, the identification of transition lines by Balmer, Lyman and others, the empirical description of allowed wavelengths by Rydberg, the quantum model of Bohr, the capability of quantum electrodynamics to precisely predict transition frequencies, and modern measurements of the 1S–2S transition by Hänsch to a precision of a few parts in 1015. Recent technological advances have allowed us to focus on antihydrogen—the antimatter equivalent of hydrogen. The Standard Model predicts that there should have been equal amounts of matter and antimatter in the primordial Universe after the Big Bang, but today’s Universe is observed to consist almost entirely of ordinary matter. This motivates the study of antimatter, to see if there is a small asymmetry in the laws of physics that govern the two types of matter. In particular, the CPT (charge conjugation, parity reversal and time reversal) theorem, a cornerstone of the Standard Model, requires that hydrogen and antihydrogen have the same spectrum. Here we report the observation of the 1S–2S transition in magnetically trapped atoms of antihydrogen. We determine that the frequency of the transition, which is driven by two photons from a laser at 243 nanometres, is consistent with that expected for hydrogen in the same environment. This laser excitation of a quantum state of an atom of antimatter represents the most precise measurement performed on an anti-atom. Our result is consistent with CPT invariance at a relative precision of about 2 × 10−10.

Description: The study focuses on the Guyana–Suriname transform margin, utilizing well and reflection seismic data. Both datasets allow the permeability stratigraphy to be interpreted. It consists of areally extensive reservoir horizons separated by intraformational shale horizons and erosional unconformities. The youngest strata are deformed by the two generations of gravity glides, which took place fairly late in post-break-up history. Hydrocarbon shows from wells indicate that strata deformed by gravity glides are the only sedimentary packages where the vertical hydrocarbon migration dominates. Clusters of oil and gas shows have random spatial distribution in respective reservoir horizons within gravity glides. The base of the rock volume with dominating vertical migration is determined by the detachment horizon of the gravity-glide system. However, the areas unaffected by gravity glides are dominated by lateral migration, causing zonal distribution of oil and gas shows. Oil shows occur in wells penetrating the proximal margin and gas shows are found in wells penetrating the distal margin in respective reservoir horizons. Both sets are fed by the source rock occurring in the oceanic basin and the adjacent distal margin. The best example of this situation is provided by the Paleocene–Eocene reservoirs.

Description: We have previously demonstrated an increased DNA copy number and expression of IGF1R to be associated with poor outcome in Wilms tumors. We have now tested whether inhibiting this receptor may be a useful therapeutic strategy by using a panel of Wilms tumor cell lines. Both genetic and pharmacological targeting resulted in inhibition of downstream signaling through PI3 and MAP kinases, G1 cell cycle arrest, and cell death, with drug efficacy dependent on the levels of phosphorylated IGF1R. These effects were further associated with specific gene expression signatures reflecting pathway inhibition, and conferred synergistic chemosensitisation to doxorubicin and topotecan. In the in vivo setting, s.c. xenografts of WiT49 cells resembled malignant rhabdoid tumors rather than Wilms tumors. Treatment with an IGF1R inhibitor (NVP-AEW541) showed no discernable antitumor activity and no downstream pathway inactivation. By contrast, Wilms tumor cells established orthotopically within the kidney were histologically accurate and exhibited significantly elevated insulin-like growth factor–mediated signaling, and growth was significantly reduced on treatment with NVP-AEW541 in parallel with signaling pathway ablation. As a result of the paracrine effects of enhanced IGF2 expression in Wilms tumor, this disease may be acutely dependent on signaling through the IGF1 receptor, and thus treatment strategies aimed at its inhibition may be useful in the clinic. Such efficacy may be missed if only standard ectopic models are considered as a result of an imperfect recapitulation of the specific tumor microenvironment.

Description: This study examines field portable X-ray fluorescence (pXRF) data for unsieved B- and C-horizon soil samples from two contrasting Au exploration programs in northern Canada and compares them to laboratory results from sieved samples to determine if a minimalist approach to sample preparation, equipment calibration and analysis produces results that are adequate for exploration purposes. The collection of 14 651 residual soil samples on detailed grids at the Whiskey Au project in the Black Hills of the Yukon Territory, Canada during the 2011 field season allows a comparison of pXRF data from unsieved samples with inductively-coupled plasma mass spectrometry (ICP-MS) data from the 〈100-µm grain size fraction digested in aqua regia. XRF data were generated on two devices: an Innov-X Delta handheld and a Niton FXL desk-top unit. Data for selected elements from the pXRF units show trends in gridded percentile plots comparable to the ICP-MS data, although the continuity of these trends reflects the degree to which the pathfinder element concentrations exceed the lower orders of detection. Acceptable merged gridded images for As and Cu from the two devices were generated without data levelling, whereas the Pb, Mo and Ni data require leveling prior to gridding in order to provide a reasonable fit to the laboratory data. Data for elements that occur in concentrations close to the lower limit of detection by pXRF, such as Sb, may provide some useful information but must be used with caution. Data for Fe also show a poor correlation, possibly due to heterogeneity of Fe in the samples, as well as due to incomplete digestion of all Fe-bearing minerals in some samples using an aqua regia digestion. A total of 680 till samples collected from regional and detailed sampling grids on the Kiyuk Lake Au property in southern Nunavut, Canada during the 2012 field season were analysed by pXRF and also by ICP-MS following an aqua regia digestion. pXRF data were generated on an Innov-X Delta using unsieved samples for comparison with ICP-MS data from the 〈70-µm grain size fraction. The pathfinder element As shows good agreement with the laboratory data, whereas Ni, Mo and Sb data give poor matches due to proximity of the data to the lower orders of detection by pXRF. The use of pXRF data on soil samples with no sample preparation other than drying and no instrument calibration is a robust approach for Au exploration using particular elements, such As and Cu, provided the data are monitored for consistency. Even greater compatibility between pXRF and laboratory data would be expected where sample preparation and site-specific calibrations are implemented. Other pathfinder elements for Au, including W, Sb, Bi, Ag and Te, as well as Au itself, typically occur at levels in soil either close to or below the lower order of detection of the current generation of field-portable analytical devices. The use of pXRF in Au exploration allows for quick decision-making and provides near-real time sampling guidance in the field where ‘fit for purpose’ data for suitable pathfinder and lithologically-controlled elements can be obtained.

Description: Tissue-resident macrophages are heterogeneous as a consequence of anatomical niche-specific functions. Many populations self-renew independently of bone marrow in the adult, but the molecular mechanisms of this are poorly understood. We determined a transcriptional profile for the major self-renewing population of peritoneal macrophages in mice. These cells specifically expressed the transcription factor Gata6. Selective deficiency of Gata6 in myeloid cells caused substantial alterations in the transcriptome of peritoneal macrophages. Gata6 deficiency also resulted in dysregulated peritoneal macrophage proliferative renewal during homeostasis and in response to inflammation, which was associated with delays in the resolution of inflammation. Our investigations reveal that the tissue macrophage phenotype is under discrete tissue-selective transcriptional control and that this is fundamentally linked to the regulation of their proliferation renewal.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4185421/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4185421/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rosas, Marcela -- Davies, Luke C -- Giles, Peter J -- Liao, Chia-Te -- Kharfan, Bashar -- Stone, Timothy C -- O'Donnell, Valerie B -- Fraser, Donald J -- Jones, Simon A -- Taylor, Philip R -- 094143/Wellcome Trust/United Kingdom -- G0601617/Medical Research Council/United Kingdom -- MR/J002151/1/Medical Research Council/United Kingdom -- MR/K02003X/1/Medical Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- New York, N.Y. -- Science. 2014 May 9;344(6184):645-8. doi: 10.1126/science.1251414. Epub 2014 Apr 24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cardiff Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24762537" target="_blank"〉PubMed〈/a〉

Description: Purine biosynthetic enzymes organize into dynamic cellular bodies called purinosomes. Little is known about the spatiotemporal control of these structures. Using super-resolution microscopy, we demonstrated that purinosomes colocalized with mitochondria, and these results were supported by isolation of purinosome enzymes with mitochondria. Moreover, the number of purinosome-containing cells responded to dysregulation of mitochondrial function and metabolism. To explore the role of intracellular signaling, we performed a kinome screen using a label-free assay and found that mechanistic target of rapamycin (mTOR) influenced purinosome assembly. mTOR inhibition reduced purinosome-mitochondria colocalization and suppressed purinosome formation stimulated by mitochondria dysregulation. Collectively, our data suggest an mTOR-mediated link between purinosomes and mitochondria, and a general means by which mTOR regulates nucleotide metabolism by spatiotemporal control over protein association.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉French, Jarrod B -- Jones, Sara A -- Deng, Huayun -- Pedley, Anthony M -- Kim, Doory -- Chan, Chung Yu -- Hu, Haibei -- Pugh, Raymond J -- Zhao, Hong -- Zhang, Youxin -- Huang, Tony Jun -- Fang, Ye -- Zhuang, Xiaowei -- Benkovic, Stephen J -- 1R33EB019785-01/EB/NIBIB NIH HHS/ -- GM024129/GM/NIGMS NIH HHS/ -- Canadian Institutes of Health Research/Canada -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2016 Feb 12;351(6274):733-7. doi: 10.1126/science.aac6054.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Cell Biology, Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA. jarrod.french@stonybrook.edu fangy2@corning.com zhuang@chemistry.harvard.edu sjb1@psu.edu. ; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA. ; Biochemical Technologies, Science and Technology Division, Corning Incorporated, Corning, NY 14831, USA. ; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA. ; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA. Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA. ; Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA. ; Biochemical Technologies, Science and Technology Division, Corning Incorporated, Corning, NY 14831, USA. jarrod.french@stonybrook.edu fangy2@corning.com zhuang@chemistry.harvard.edu sjb1@psu.edu. ; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA. Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA. Department of Physics, Harvard University, Cambridge, MA 02138, USA. jarrod.french@stonybrook.edu fangy2@corning.com zhuang@chemistry.harvard.edu sjb1@psu.edu. ; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA. jarrod.french@stonybrook.edu fangy2@corning.com zhuang@chemistry.harvard.edu sjb1@psu.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26912862" target="_blank"〉PubMed〈/a〉

Description: Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| 〈 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known to be no greater than about 10(-21)e for a diverse range of species including H2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge, then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ahmadi, M -- Baquero-Ruiz, M -- Bertsche, W -- Butler, E -- Capra, A -- Carruth, C -- Cesar, C L -- Charlton, M -- Charman, A E -- Eriksson, S -- Evans, L T -- Evetts, N -- Fajans, J -- Friesen, T -- Fujiwara, M C -- Gill, D R -- Gutierrez, A -- Hangst, J S -- Hardy, W N -- Hayden, M E -- Isaac, C A -- Ishida, A -- Jones, S A -- Jonsell, S -- Kurchaninov, L -- Madsen, N -- Maxwell, D -- McKenna, J T K -- Menary, S -- Michan, J M -- Momose, T -- Munich, J J -- Nolan, P -- Olchanski, K -- Olin, A -- Povilus, A -- Pusa, P -- Rasmussen, C O -- Robicheaux, F -- Sacramento, R L -- Sameed, M -- Sarid, E -- Silveira, D M -- So, C -- Tharp, T D -- Thompson, R I -- van der Werf, D P -- Wurtele, J S -- Zhmoginov, A I -- England -- Nature. 2016 Jan 21;529(7586):373-6. doi: 10.1038/nature16491.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of Liverpool, Liverpool L697ZE, UK. ; Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA. ; Centre de Recherches en Physique des Plasmas (CRPP), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland. ; School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. ; Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, UK. ; Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, UK. ; Physics Department, European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23, Switzerland. ; Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada. ; Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil. ; Department of Physics, Swansea University, Swansea SA2 8PP, UK. ; Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. ; Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark. ; TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada. ; Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. ; Department of Physics, Stockholm University, SE-10691, Stockholm, Sweden. ; Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada. ; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada. ; Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA. ; Soreq Nuclear Research Center, Yavne, 81800, Israel. ; Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada. ; ATAP, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26791725" target="_blank"〉PubMed〈/a〉

Description: Denitrification and hydrologic leaching are the two major pathways by which nitrogen is lost from the terrestrial biosphere. Humid tropical forests are thought to dominate denitrification from unmanaged lands globally, but there is large uncertainty about the range and key drivers of total N gas emissions across the biome. We combined pantropical measures of small watershed stream chemistry with ecosystem modeling to determine total nitrogen gas losses and associated uncertainty across humid tropical forests. Our calculations reveal that denitrification in soils and along hydrologic flowpaths contributes on average 〉45% of total watershed N losses. However, when denitrification occurs exclusively in shallow soils, simulations indicate that gas emissions would exceed N inputs and render plants severely N-limited, which contradicts observations of widespread N-sufficiency in tropical forests. Our analyses suggest an upper bound on soil denitrification of ~80% of total external N losses beyond which tropical plant growth would be compromised.