bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of solid-state complex organic molecules through accretion of simple species at low temperatures
Authors: Qasim D. , Fedoseev G. , Chuang K.-J. , Taquet V. , Lamberts T. , He J. , Ioppolo S. , van Dishoeck E. F. , Linnartz H. 
Published: October 2020

AbstractComplex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through ‘non-energetic’ processes. In this contribution, we show that propanal and 1-propanol can be formed in this way at the low temperature of 10 K. Propanal has already been detected in space. 1-propanol is an astrobiologically relevant molecule, as it is a primary alcohol, and has not been astronomically detected. Propanal is the major product formed in the C2H2 + CO + H experiment, and 1-propanol is detected in the subsequent propanal + H experiment. ALMA observations towards IRAS 16293-2422B are discussed and provide a 1-propanol:propanal upper limit of < 0.35–0.55, which are complemented by computationally-derived activation barriers in addition to the performed laboratory experiments.
Observations of the photochemical evolution of carbonaceous macromolecules in star-forming regions
Authors: Berné Olivier 
Published: October 2020

AbstractThe goal of this contribution is to illustrate how spatially resolved spectroscopic observations of the infrared emission of UV irradiated regions, from star forming regions to the diffuse ISM, can be used to rationalize the chemical evolution of carbonaceous macromolecules in space, with the help of astrophysical models. For instance, observations with the Spitzer space telescope lead to the idea that fullerenes (including C60 can form top-down from Polycyclic Aromatic Hydrocarbons in the interstellar medium. The possibility that this process can occur in space was tested using a photochemical model which includes the key molecular parameters derived from experimental and theoretical studies. This approach allows to test the likelihood that the proposed path is realistic, but, more importantly, it allows to isolate the key physical processes and parameters that are required to capture correctly the evolution of carbonaceous molecules in space. In this specific case, we found that relaxation through thermally excited electronic states (a physical mechanism that is largely unexplored, except by few a teams) is one of the keys to model the photochemistry of the considered species. Subsequent quantum chemical studies stimulated by the (limited) astrophysical model showed that a detailed mapping of the energetics of isomerization and de-hydrogenation is necessary to understand the competition between these processes in space.Such approaches, involving experimentalists and theoreticians, are particularly promising in the context of the upcoming JWST mission, which will provide access to the signatures of carbonaceous species in emission and in absorption at an angular resolution that will enable to reach new chemical frontiers in star and even in planet forming regions.
The Wootton center for astrophysical plasma properties: First results for helium
Authors: Montgomery M. H. , Winget D. E. , Schaeuble M.-A. , Dunlap B. H. , Fuchs J. T. 
Published: October 2020

AbstractThe Wootton Center for Astrophysical Plasma Properties (WCAPP) is a new center focusing on the spectroscopic properties of stars and accretion disks using “at-parameter” experiments. Currently, these experiments use the X-ray output of the Z machine at Sandia National Laboratories — the largest X-ray source in the world — to heat plasmas to the same conditions (temperature, density, and radiation environment) as those observed in astronomical objects. The experiments include measuring (1) density-dependent opacities of iron-peak elements at solar interior conditions, (2) spectral lines of low-Z elements at white dwarf photospheric conditions, (3) atomic population kinetics of neon in a radiation-dominated environment, and (4) resonant Auger destruction (RAD) of silicon at conditions found in accretion disks around supermassive black holes. In particular, we report on recent results of our experiments involving helium at white dwarf photospheric conditions. We present results showing disagreement between inferred electron densities using the Hβ line and the He I 5876 Å line, most likely indicating incompleteness in our modeling of this helium line.
Recent advances in experimental laboratory astrophysics for stellar astrophysics applications and future data needs
Authors: Pickering Juliet C. , Teresa Belmonte Maria , Clear Christian P. , Liggins Florence , Concepcion-Mairey Florence 
Published: October 2020

AbstractAccurate atomic data for line wavelengths, energy levels, line broadening such as hyperfine structure and isotope structure, and f-values, particularly for the line rich iron group elements, are needed for stellar astrophysics applications, and examples of recent measurements are given. These atomic data are essential for determination of elemental abundances in astronomical objects. With modern facilities, telescopes and spectrographs, access to underexplored regions (IR, UV, VUV), and improved stellar atmosphere models (3D, NLTE), and extremely large datasets, astronomers are tackling problems ranging from studying Galactic chemical evolution, to low mass stars and exoplanets. Such advances require improved accuracy and completeness of the atomic database for analyses of astrophysical spectra.
Simulations of energy dissipation and non-thermal desorption on amorphous solid water
Authors: Cuppen H. M. , Fredon A. 
Published: October 2020

AbstractDust particles covered by icy mantles play a crucial role in the formation of molecules in the Interstellar Medium (ISM). These icy mantles are mainly composed of water but many other chemical species are also contained in these ices. These compounds can diffuse and meet each other to react. It is through these surface reactions that new saturated species are formed. Photodissociation reactions are also thought to play a crucial role in the formation of radical species. Complex organic molecules are formed through an intricated network of photodissociation and surface reactions.Both type of reactions release energy. Surface reactions are typically exothermic by a few eV, whereas photodissociation reactions are triggered by the absorption of a UV photon, resulting in the formation of highly excited products. The excited reaction products can apply this energy for desorption or diffusion, making products more mobile than predicted when considering only thermal hopping. The energy could further lead to annealing or deformation of the ice structure.Here we would like to quantify the relative importance of these different energy dissipation routes. For this we performed thousands of Molecular Dynamics simulations for three different species (CO2, H2O and CH4) on top of a water ice surface. We consider different types of excitation such as translational, rotational, and/or vibrational excitation. The applied substrate is an amorphous solid water surface (ASW).
TERMINAL FLOWER 1-FD complex target genes and competition with FLOWERING LOCUS T
Authors: Zhu Yang , Klasfeld Samantha , Jeong Cheol Woong , Jin Run , Goto Koji , Yamaguchi Nobutoshi , Wagner Doris 
Published: October 2020

AbstractPlants monitor seasonal cues to optimize reproductive success by tuning onset of reproduction and inflorescence architecture. TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) and their orthologs antagonistically regulate these life history traits, yet their mechanism of action, antagonism and targets remain poorly understood. Here, we show that TFL1 is recruited to thousands of loci by the bZIP transcription factor FD. We identify the master regulator of floral fate, LEAFY (LFY) as a target under dual opposite regulation by TFL1 and FT and uncover a pivotal role of FT in promoting flower fate via LFY upregulation. We provide evidence that the antagonism between FT and TFL1 relies on competition for chromatin-bound FD at shared target loci. Direct TFL1-FD regulated target genes identify this complex as a hub for repressing both master regulators of reproductive development and endogenous signalling pathways. Our data provide mechanistic insight into how TFL1-FD sculpt inflorescence architecture, a trait important for reproductive success, plant architecture and yield.
Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits
Authors: Miyauchi Shingo , Kiss Enikő , Kuo Alan , Drula Elodie , Kohler Annegret , Sánchez-García Marisol , Morin Emmanuelle , Andreopoulos Bill , Barry Kerrie W. , Bonito Gregory , Buée Marc , Carver Akiko , Chen Cindy , Cichocki Nicolas , Clum Alicia , Culley David , Crous Pedro W. , Fauchery Laure , Girlanda Mariangela , Hayes Richard D. , Kéri Zsófia , LaButti Kurt , Lipzen Anna , Lombard Vincent , Magnuson Jon , Maillard François , Murat Claude , Nolan Matt , Ohm Robin A. , Pangilinan Jasmyn , Pereira Maíra de Freitas , Perotto Silvia , Peter Martina , Pfister Stephanie , Riley Robert , Sitrit Yaron , Stielow J. Benjamin , Szöllősi Gergely , Žifčáková Lucia , Štursová Martina , Spatafora Joseph W. , Tedersoo Leho , Vaario Lu-Min , Yamada Akiyoshi , Yan Mi , Wang Pengfei , Xu Jianping , Bruns Tom , Baldrian Petr , Vilgalys Rytas , Dunand Christophe , Henrissat Bernard , Grigoriev Igor V. , Hibbett David , Nagy László G. , Martin Francis M. 
Published: October 2020

AbstractMycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.
Stabilizing a metalloid {Zn12} unit within a polymetallide environment in [K2Zn20Bi16]6−
Authors: Eulenstein Armin R. , Franzke Yannick J. , Bügel Patrick , Massa Werner , Weigend Florian , Dehnen Stefanie 
Published: October 2020

AbstractThe access to molecules comprising direct Zn–Zn bonds has become very topical in recent years for various reasons. Low-valent organozinc compounds show remarkable reactivities, and larger Zn–Zn-bonded gas-phase species exhibit a very unusual coexistence of insulating and metallic properties. However, as Zn atoms do not show a high tendency to form clusters in condensed phases, synthetic approaches for generating purely inorganic metalloid Znx units under ambient conditions have been lacking so far. Here we show that the reaction of a highly reductive solid with the nominal composition K5Ga2Bi4 with ZnPh2 at room temperature yields the heterometallic cluster anion [K2Zn20Bi16]6–. A 24-atom polymetallide ring embeds a metalloid {Zn12} unit. Density functional theory calculations reveal multicenter bonding, an essentially zero-valent situation in the cluster center, and weak aromaticity. The heterometallic character, the notable electron-delocalization, and the uncommon nano-architecture points at a high potential for nano-heterocatalysis.
Jagged1-Notch1-deployed tumor perivascular niche promotes breast cancer stem cell phenotype through Zeb1
Authors: Jiang Huimin , Zhou Chen , Zhang Zhen , Wang Qiong , Wei Huimin , Shi Wen , Li Jianjun , Wang Zhaoyang , Ou Yang , Wang Wenhao , Wang Hang , Zhang Quansheng , Sun Wei , Sun Peiqing , Yang Shuang 
Published: October 2020

AbstractZinc finger E-box binding homeobox 1 (Zeb1) has been demonstrated to participate in the acquisition of the properties of cancer stem cells (CSCs). However, it is largely unknown how signals from the tumor microenvironment (TME) contribute to aberrant Zeb1 expression. Here, we show that Zeb1 depletion suppresses stemness, colonization and the phenotypic plasticity of breast cancer. Moreover, we demonstrate that, with direct cell-cell contact, TME-derived endothelial cells provide the Notch ligand Jagged1 (Jag1) to neighboring breast CSCs, leading to Notch1-dependent upregulation of Zeb1. In turn, ectopic Zeb1 in tumor cells increases VEGFA production and reciprocally induces endothelial Jag1 in a paracrine manner. Depletion of Zeb1 disrupts this positive feedback loop in the tumor perivascular niche, which eventually lessens tumor initiation and progression in vivo and in vitro. In this work, we highlight that targeting the angiocrine Jag1-Notch1-Zeb1-VEGFA loop decreases breast cancer aggressiveness and thus enhances the efficacy of antiangiogenic therapy.
High-throughput mutagenesis reveals unique structural features of human ADAR1
Authors: Park SeHee , Doherty Erin E. , Xie Yixuan , Padyana Anil K. , Fang Fang , Zhang Yue , Karki Agya , Lebrilla Carlito B. , Siegel Justin B. , Beal Peter A. 
Published: October 2020

AbstractAdenosine Deaminases that act on RNA (ADARs) are enzymes that catalyze adenosine to inosine conversion in dsRNA, a common form of RNA editing. Mutations in the human ADAR1 gene are known to cause disease and recent studies have identified ADAR1 as a potential therapeutic target for a subset of cancers. However, efforts to define the mechanistic effects for disease associated ADAR1 mutations and the rational design of ADAR1 inhibitors are limited by a lack of structural information. Here, we describe the combination of high throughput mutagenesis screening studies, biochemical characterization and Rosetta-based structure modeling to identify unique features of ADAR1. Importantly, these studies reveal a previously unknown zinc-binding site on the surface of the ADAR1 deaminase domain which is important for ADAR1 editing activity. Furthermore, we present structural models that explain known properties of this enzyme and make predictions about the role of specific residues in a surface loop unique to ADAR1.
COMPOSITUM 1 contributes to the architectural simplification of barley inflorescence via meristem identity signals
Authors: Poursarebani Naser , Trautewig Corinna , Melzer Michael , Nussbaumer Thomas , Lundqvist Udda , Rutten Twan , Schmutzer Thomas , Brandt Ronny , Himmelbach Axel , Altschmied Lothar , Koppolu Ravi , Youssef Helmy M. , Sibout Richard , Dalmais Marion , Bendahmane Abdelhafid , Stein Nils , Xin Zhanguo , Schnurbusch Thorsten 
Published: October 2020

AbstractGrasses have varying inflorescence shapes; however, little is known about the genetic mechanisms specifying such shapes among tribes. Here, we identify the grass-specific TCP transcription factor COMPOSITUM 1 (COM1) expressing in inflorescence meristematic boundaries of different grasses. COM1 specifies branch-inhibition in barley (Triticeae) versus branch-formation in non-Triticeae grasses. Analyses of cell size, cell walls and transcripts reveal barley COM1 regulates cell growth, thereby affecting cell wall properties and signaling specifically in meristematic boundaries to establish identity of adjacent meristems. COM1 acts upstream of the boundary gene Liguleless1 and confers meristem identity partially independent of the COM2 pathway. Furthermore, COM1 is subject to purifying natural selection, thereby contributing to specification of the spike inflorescence shape. This meristem identity pathway has conceptual implications for both inflorescence evolution and molecular breeding in Triticeae.
Reptile-like physiology in Early Jurassic stem-mammals
Authors: Newham Elis , Gill Pamela G. , Brewer Philippa , Benton Michael J. , Fernandez Vincent , Gostling Neil J. , Haberthür David , Jernvall Jukka , Kankaanpää Tuomas , Kallonen Aki , Navarro Charles , Pacureanu Alexandra , Richards Kelly , Brown Kate Robson , Schneider Philipp , Suhonen Heikki , Tafforeau Paul , Williams Katherine A. , Zeller-Plumhoff Berit , Corfe Ian J. 
Published: October 2020

AbstractDespite considerable advances in knowledge of the anatomy, ecology and evolution of early mammals, far less is known about their physiology. Evidence is contradictory concerning the timing and fossil groups in which mammalian endothermy arose. To determine the state of metabolic evolution in two of the earliest stem-mammals, the Early JurassicMorganucodonandKuehneotherium, we use separate proxies for basal and maximum metabolic rate. Here we report, using synchrotron X-ray tomographic imaging of incremental tooth cementum, that they had maximum lifespans considerably longer than comparably sized living mammals, but similar to those of reptiles, and so they likely had reptilian-level basal metabolic rates. Measurements of femoral nutrient foramina showMorganucodonhad blood flow rates intermediate between living mammals and reptiles, suggesting maximum metabolic rates increased evolutionarily before basal metabolic rates. Stem mammals lacked the elevated endothermic metabolism of living mammals, highlighting the mosaic nature of mammalian physiological evolution.
AKT-induced lncRNA VAL promotes EMT-independent metastasis through diminishing Trim16-dependent Vimentin degradation
Authors: Tian Han , Lian Rong , Li Yun , Liu Chenying , Liang Shujun , Li Wei , Tao Tianyu , Wu Xingui , Ye Yaokai , Yang Xia , Han Jian , Chen Xuwei , Li Jun , He Yukai , Li Mengfeng , Wu Jueheng , Cai Junchao 
Published: October 2020

AbstractDespite the importance of AKT overactivation in tumor progression, results from clinical trials of various AKT inhibitors remain suboptimal, suggesting that AKT-driven tumor metastasis needs to be further understood. Herein, based on long non-coding RNA (lncRNA) profiling induced by active AKT, we identify that VAL (Vimentin associated lncRNA, LINC01546), which is directly induced by AKT/STAT3 signaling, functions as a potent pro-metastatic molecule and is essential for active AKT-induced tumor invasion, metastasis and anoikis resistance in lung adenocarcinoma (LAD). Impressively, chemosynthetic siRNAs against VAL shows great therapeutic potential in AKT overactivation-driven metastasis. Interestingly, similar to activated AKT in LAD cells, although unable to induce epithelial-mesenchymal transition (EMT), VAL exerts potent pro-invasive and pro-metastatic effects through directly binding to Vimentin and competitively abrogating Trim16-depedent Vimentin polyubiquitination and degradation. Taken together, our study provides an interesting demonstration of a lncRNA-mediated mechanism for active AKT-driven EMT-independent LAD metastasis and indicates the great potential of targeting VAL or Vimentin stability as a therapeutic approach.
Analysis of SARS-CoV-2 vertical transmission during pregnancy
Authors: Fenizia Claudio , Biasin Mara , Cetin Irene , Vergani Patrizia , Mileto Davide , Spinillo Arsenio , Gismondo Maria Rita , Perotti Francesca , Callegari Clelia , Mancon Alessandro , Cammarata Selene , Beretta Ilaria , Nebuloni Manuela , Trabattoni Daria , Clerici Mario , Savasi Valeria 
Published: October 2020

AbstractThe impact of SARS-CoV-2 infection during gestation remains unclear. Here, we analyse the viral genome on maternal and newborns nasopharyngeal swabs, vaginal swabs, maternal and umbilical cord plasma, placenta and umbilical cord biopsies, amniotic fluids and milk from 31 mothers with SARS-CoV-2 infection. In addition, we also test specific anti-SARS-CoV-2 antibodies and expression of genes involved in inflammatory responses in placentas, and in maternal and umbilical cord plasma. We detect SARS-CoV-2 genome in one umbilical cord blood and in two at-term placentas, in one vaginal mucosa and in one milk specimen. Furthermore, we report the presence of specific anti-SARS-CoV-2 IgM and IgG antibodies in one umbilical cord blood and in one milk specimen. Finally, in the three documented cases of vertical transmission, SARS-CoV-2 infection was accompanied by a strong inflammatory response. Together, these data support the hypothesis that in utero SARS-CoV-2 vertical transmission, while low, is possible. These results might help defining proper obstetric management of COVID-19 pregnant women, or putative indications for mode and timing of delivery.
Multi-functional flexible 2D carbon nanostructured networks
Authors: Zhang Shichao , Liu Hui , Yu Jianyong , Li Bingyun , Ding Bin 
Published: October 2020

AbstractTwo-dimensional network-structured carbon nanoscale building blocks, going beyond graphene, are of fundamental importance, and creating such structures and developing their applications have broad implications in environment, electronics and energy. Here, we report a facile route, based on electro-spraying/netting, to self-assemble two-dimensional carbon nanostructured networks on a large scale. Manipulation of the dynamic ejection, deformation and assembly of charged droplets by control of Taylor cone instability and micro-electric field, enables the creation of networks with characteristics combining nanoscale diameters of one-dimensional carbon nanotube and lateral infinity of two-dimensional graphene. The macro-sized (meter-level) carbon nanostructured networks show extraordinary nanostructural properties, remarkable flexibility (soft polymeric mechanics having hard inorganic matrix), nanoscale-level conductivity, and outstanding performances in distinctly different areas like filters, separators, absorbents, and wearable electrodes, supercapacitors and cells. This work should make possible the innovative design of high-performance, multi-functional carbon nanomaterials for various applications.
Andean drought and glacial retreat tied to Greenland warming during the last glacial period
Authors: Woods Arielle , Rodbell Donald T. , Abbott Mark B. , Hatfield Robert G. , Chen Christine Y. , Lehmann Sophie B. , McGee David , Weidhaas Nicholas C. , Tapia Pedro M. , Valero-Garcés Blas L. , Bush Mark B. , Stoner Joseph S. 
Published: October 2020

AbstractAbrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how these changes affected precipitation and Andean glacier mass balance. Here we present a sediment record spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes that has sufficient chronologic precision to document abrupt climatic events on a centennial-millennial time scale. DO events involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake. Our results reveal the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the SASM during abrupt arctic warming. Accentuated warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance of the southern tropical Andes with deleterious effects on this densely populated region of South America.