bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Multidisciplinary Approach for the Thermo‐Rheological Study of Volcanic Areas: The Case Study of Long Valley Caldera
Authors: Gola G. , Barone A. , Castaldo R. , Chiodini G. , D'Auria L. , García‐Hernández R. , Pepe S. , Solaro G. , Tizzani P. 
Published: December 2020

AbstractWe propose a novel multidisciplinary approach to image the thermo‐rheological stratification beneath active volcanic areas, such as Long Valley Caldera (LVC). We performed a thermal fluid dynamic model via optimization procedure of the thermal conditions of the crust. We characterize the topology of the hot magmatic bodies and the hot fluid circulation (the permeable fault‐zones), using both a novel imaging of the a and b parameters of the Gutenberg‐Richter law and an innovative procedure analysis of P‐wave tomographic models. The optimization procedure provides the permeability of a reservoir (5.0 × 10−14 m2) and of the fault‐zone (5.0 · 10−14 – 1.0 × 10−13 m2), as well as the temperature of the magma body (750–800°C). The imaging of the rheological properties of the crust indicates that the brittle/ductile transition occurs about 5 km b.s.l. depth, beneath the resurgent dome. There are again deeper brittle conditions about 15 km b.s.l., agreeing with the previous observations. The comparison between the conductive and the conductive‐convective heat transfer models highlights that the deeper fluid circulation efficiently cools the volumes above the magmatic body, transferring the heat to the shallow geothermal system. This process has a significant impact on the rheological properties of the upper crust as the migration of the B/D transition. Our findings show an active magmatic system (6–10 km deep) and confirm that LVC is a long‐life silicic caldera system.
Subsurface Geometry and Emplacement Conditions of a Giant Dike System in Elysium Fossae, Mars
Authors: Rivas‐Dorado Sam , Ruiz Javier , Romeo Ignacio 
Published: December 2020

AbstractElysium Fossae is a NW‐SE, 350 km‐long linear graben system located in the eastern flank of Elysium Mons, Mars. Graben widths, lengths, and topographic data were used to model the thicknesses, depths, heights, and excess pressures of a possible dike system underneath these grabens. Area balance on topographic profiles across the structures reveals dikes at depths of 241–2,330 m below the surface, with average thicknesses <60 m, and heights of 15–20 km. These heights are approximately three times larger than terrestrial dikes intruded in the shallow crust. The subsurface properties suggest a teardrop‐shape geometry for the dikes, which has been observed in many theoretical and analog dike models. Additionally, the aspect ratios (thicknesses and lengths) of the inferred dikes are consistent with sublinear scaling, characteristic of fluid‐induced fractures. The obtained critical stress intensity factors (Kic) are between 3.14 and 15.15 GPa·m1/2 and are slightly higher than those of terrestrial dikes intruded in similar lithologies. The maximum excess pressures calculated from stress intensity factors are between 31 and 276 MPa. These are also consistent with pressures calculated for terrestrial dikes despite the greater aperture and height of the Elysium dikes. Theoretical calculations of excess pressures for variable dike heights support both the values calculated from empirical observations, and that Martian dike heights may consistently be three times the heights of terrestrial dikes. In summary, this work supports: (1) the existence of a dike system underneath Elysium and (2) that dike heights in rocky planets may scale inversely with gravitational acceleration.
Rockwall Slope Erosion in the Northwestern Himalaya
Authors: Orr Elizabeth N. , Owen Lewis A. , Saha Sourav , Hammer Sarah J. , Caffee Marc W. 
Published: December 2020

AbstractRockwall slope erosion is an important component of alpine landscape evolution, yet the role of climate and tectonics in driving this erosion remains unclear. We define the distribution and magnitude of periglacial rockwall slope erosion across 12 catchments in Himachal Pradesh and Jammu and Kashmir in the Himalaya of northern India using cosmogenic 10Be concentrations in sediment from medial moraines. Beryllium‐10 concentrations range from 0.5 ± 0.04 × 104 to 260.0 ± 12.5 × 104 at/g SiO2, which yield erosion rates between 7.6 ± 1.0 and 0.02 ± 0.004 mm/a. Between ∼0.02 and ∼8 m of rockwall slope erosion would be possible in this setting across a single millennium, and >2 km when extrapolated for the Quaternary period. This erosion affects catchment sediment flux and glacier dynamics, and helps to establish the pace of topographic change at the headwaters of catchments. We combine rockwall erosion records from the Himalaya of Himachal Pradesh, Jammu and Kashmir, and Uttarakhand in India and Baltistan in Pakistan to create a regional erosion data set. Rockwall slope erosion rates progressively decrease with distance north from the Main Central Thrust and into the interior of the orogen. The distribution and magnitude of this erosion is most closely associated with records of Himalayan denudation and rock uplift, where the highest rates of change are recorded in the Greater Himalaya sequences. This suggests that tectonically driven uplift, rather than climate, is a first order control on patterns of rockwall slope erosion in the northwestern Himalaya. Precipitation and temperature would therefore come as secondary controls.
Reconstructing Depositional Rates and Their Effect on Paleoenvironmental Proxies: The Case of the Lau Carbon Isotope Excursion in Gotland, Sweden
Authors: Jarochowska E. , Nohl T. , Grohganz M. , Hohmann N. , Vandenbroucke T. R. A. , Munnecke A. 
Published: December 2020

AbstractVariations in depositional rates affect the temporal depositional resolutions of proxies used for paleoenvironmental reconstructions; for example, condensation can make reconstructed environmental changes appear very abrupt. This is commonly addressed by transforming proxy data using age models, but this approach is limited to situations where numerical ages are available or can be reliably inferred by correlation. Here we propose a new solution, in which relative age models are constructed based on proxies for depositional rates. As a case study, we use the onset of the late Silurian Lau Carbon Isotope Excursion (LCIE) in Gotland, Sweden. The studied succession is a gradual record of shallowing upward in a tropical, neritic carbonate platform. As proxies for depositional rates we tested thorium concentration, carbonate content, and the concentration of pelagic palynomorphs. These three proxies were used to create relative age models using the previously published DAIME model. We applied these models to transform the δ13Ccarb values as well as concentrations of selected redox‐sensitive elements. The three relative age models yielded qualitatively similar results. In our case study, variations in depositional rates resulted in peaks of redox proxies appearing up to 76% higher when taken at face value, compared to when accounting for these rates. In the most extreme cases, our corrections resulted in a reversal in the stratigraphic trend of elemental concentrations. This approach can be applied and developed across depositional setting and types of paleoenvironmental proxies. It provides a flexible tool for developing quantitative models to improve our understanding of the stratigraphic record.
Seasonality in Holocene Temperature Reconstructions in Southwestern China
Authors: Sun Xiaoshuang , Zhao Cheng , Zhang Can , Feng Xiaoping , Yan Tianlong , Yang Xiangdong , Shen Ji 
Published: December 2020

AbstractReconstructions of global surface temperature, dominated by records from the northern extratropics, show an apparent Holocene cooling trend after the early Holocene climatic optimum. However, model simulations suggest a global warming Holocene tendency. This “Holocene temperature conundrum” may be caused by the seasonal bias of paleotemperature proxies. Here we report a quantitative Holocene record with ∼100‐year resolution based on branched glycerol dialkyl glycerol tetraethers from an alpine lake in southwestern China. Our reconstructed Holocene temperature record displays a steady long‐term trend without distinct cooling or warming changes. Based on the temperature values and their evolution over time, our reconstruction is interpreted to present temperature changes in ice‐free seasons from March to November. Unlike the often‐documented Holocene cooling of regional summer temperatures driven by boreal summer insolation, this observed trend in our reconstructed temperatures is probably caused by slightly decreasing local ice‐free season insolation and somewhat compensated by increasing atmospheric greenhouse gas concentrations. Our results demonstrate that the climatic drivers of ice‐free season and summer temperature changes could be different and highlight the significance of elucidating the seasonality of proxies before using them for paleoclimate reconstructions.
A Method for Integrating Delayed Recharge Flux Through Unsaturated Zones into Analytical and Numerical Groundwater Flow Modeling
Authors: Park Eungyu , Jeong Jina , Choung Sungwook , Han Weon Shik , Kim Kue‐Young , Suk Heejun 
Published: December 2020

AbstractThe temporal delay in the water table's response to precipitation is a common phenomenon. Using a mathematical model, we developed a function that represents the recharge flux through unsaturated zones of varying thickness to model the delayed response of groundwater level due to precipitation. The recharge flux from the developed function was integrated into the analytical and numerical models to estimate the actual groundwater levels in the unsaturated zone. The analytical and numerical models accurately determined the actual groundwater levels. Additionally, calibrated hydraulic parameters from numerical estimates reflected the values measured in the actual aquifer, thereby highlighting the potential application of the developed function to wide‐ranging groundwater problems. Based on the recharge function, a recharge module can be developed for existing flow simulators to enhance groundwater modeling.
Comparison of thrombus, gut, and oral microbiomes in Korean patients with ST-elevation myocardial infarction: a case–control study
Authors: Kwun Ju-Seung , Kang Si-Hyuck , Lee Hyo-Jung , Park Han-Ki , Lee Won-Jae , Yoon Chang-Hwan , Suh Jung-Won , Cho Young-Seok , Youn Tae-Jin , Chae In-Ho 
Published: December 2020

AbstractST-segment elevation myocardial infarction (STEMI) is characterized by thrombotic coronary artery occlusions caused by atherosclerotic plaque rupture. The gut microbiome potentially contributes to the pathogenesis of coronary artery diseases. This study investigated the microbial diversity and composition of coronary thrombi in STEMI patients and the composition of the thrombus microbiome relative to that of the oral and gut microbiomes. A case–control study was performed with 22 STEMI patients and 20 age- and sex-matched healthy controls. Coronary thrombi were acquired from STEMI patients via manual thrombus aspiration during primary coronary intervention. Oral swab and stool samples were collected from both groups, and 16S rRNA sequencing and metagenomic microbiome analyses were performed. Microbial DNA was detected in 4 of 22 coronary thrombi. Proteobacteria (p) and Bacteroidetes (p) were the most abundant phyla. The oral and gut microbiomes significantly differed between patients and healthy controls. The patient group presented microbial dysbiosis, as follows: a higher relative abundance of Proteobacteria (p) and Enterobacteriaceae (f) in the gut microbiome and a lower abundance of Firmicutes (p) and Haemophilus (g) in the oral microbiome. Furthermore, 4 significantly abundant genera were observed in the coronary thrombus in the patients: Escherichia, 1.25%; Parabacteroides, 0.25%; Christensenella, 0.0%; and Bacteroides, 7.48%. The present results indicate that the relative abundance of the gut and oral microbiomes was correlated with that of the thrombus microbiome.
Targeting multiple signaling pathways: the new approach to acute myeloid leukemia therapy
Authors: Carter Jenna L. , Hege Katie , Yang Jay , Kalpage Hasini A. , Su Yongwei , Edwards Holly , Hüttemann Maik , Taub Jeffrey W. , Ge Yubin 
Published: December 2020

AbstractAcute myeloid leukemia (AML) is the most common form of acute leukemia in adults and the second most common form of acute leukemia in children. Despite this, very little improvement in survival rates has been achieved over the past few decades. This is partially due to the heterogeneity of AML and the need for more targeted therapeutics than the traditional cytotoxic chemotherapies that have been a mainstay in therapy for the past 50 years. In the past 20 years, research has been diversifying the approach to treating AML by investigating molecular pathways uniquely relevant to AML cell proliferation and survival. Here we review the development of novel therapeutics in targeting apoptosis, receptor tyrosine kinase (RTK) signaling, hedgehog (HH) pathway, mitochondrial function, DNA repair, and c-Myc signaling. There has been an impressive effort into better understanding the diversity of AML cell characteristics and here we highlight important preclinical studies that have supported therapeutic development and continue to promote new ways to target AML cells. In addition, we describe clinical investigations that have led to FDA approval of new targeted AML therapies and ongoing clinical trials of novel therapies targeting AML survival pathways. We also describe the complexity of targeting leukemia stem cells (LSCs) as an approach to addressing relapse and remission in AML and targetable pathways that are unique to LSC survival. This comprehensive review details what we currently understand about the signaling pathways that support AML cell survival and the exceptional ways in which we disrupt them.
Metal-induced n+/n homojunction for ultrahigh electron mobility transistors
Authors: Park Ji-Min , Kim Hyoung-Do , Joh Hongrae , Jang Seong Cheol , Park Kyung , Park Yun Chang , Nahm Ho-Hyun , Kim Yong-Hyun , Jeon Sanghun , Kim Hyun-Suk 
Published: December 2020

AbstractA self-organized n+/n homojunction is proposed to achieve ultrahigh performance of thin film transistors (TFTs) based on an amorphous (Zn,Ba)SnO3 (ZBTO) semiconductor with sufficiently limited scattering centers. A deposited Al layer can induce a highly O-deficient (n+) interface layer in the back channel of a-ZBTO without damaging the front channel layer via the formation of a metal-oxide interlayer between the metal and back channel. The n+ layer can significantly improve the field-effect mobility by providing a relatively high concentration of free electrons in the front n-channel ZBTO, where the scattering of carriers is already controlled. In comparison with a Ti layer, the Al metal layer is superior, as confirmed by first-principles density functional theory (DFT) calculations, due to the stronger metal-O bonds, which make it easier to form a metal oxide AlOx interlayer through the removal of oxygen from ZBTO. The field-effect mobility of a-ZBTO with an Al capping layer can reach 153.4 cm2/Vs, which is higher than that of the pristine device, i.e., 20.8 cm2/Vs. This result paves the way for the realization of a cost-effective method for implementing indium-free ZBTO devices in various applications, such as flat panel displays and large-area electronic circuits.
Understanding filamentary growth and rupture by Ag ion migration through single-crystalline 2D layered CrPS4
Authors: Lee Mi Jung , Kim Sung-Hoon , Lee Sangik , Yoon Chansoo , Min Kyung-Ah , Choi Hyunsoo , Hong Suklyun , Lee Sungmin , Park Je-Geun , Ahn Jae-Pyoung , Park Bae Ho 
Published: December 2020

AbstractMemristive electrochemical metallization (ECM) devices based on cation migration and electrochemical metallization in solid electrolytes are considered promising for neuromorphic computing systems. Two-dimensional (2D) layered materials are emerging as potential candidates for electrolytes in reliable ECM devices due to their two-dimensionally confined material properties. However, electrochemical metallization within a single-crystalline 2D layered material has not yet been verified. Here, we use transmission electron microscopy and energy-dispersive X-ray spectroscopy to investigate the resistive switching mechanism of an ECM device containing a single-crystalline 2D layered CrPS4electrolyte. We observe the various conductive filament (CF) configurations induced by an applied voltage in an Ag/CrPS4/Au device in the initial/low-resistance/high-resistance/breakdown states. These observations provide concrete experimental evidence that CFs consisting of Ag metal can be formed inside single-crystalline 2D layered CrPS4and that their configuration can be changed by an applied voltage. Density functional theory calculations confirm that the sulfur vacancies in single-crystalline CrPS4can facilitate Ag ion migration from the active electrode layer. The electrically induced changes in Ag CFs inside single-crystalline 2D layered CrPS4raise the possibility of a reliable ECM device that exploits the properties of two-dimensionally confined materials.
Single-cell atlas of the first intra-mammalian developmental stage of the human parasite Schistosoma mansoni
Authors: Diaz Soria Carmen Lidia , Lee Jayhun , Chong Tracy , Coghlan Avril , Tracey Alan , Young Matthew D. , Andrews Tallulah , Hall Christopher , Ng Bee Ling , Rawlinson Kate , Doyle Stephen R. , Leonard Steven , Lu Zhigang , Bennett Hayley M. , Rinaldi Gabriel , Newmark Phillip A. , Berriman Matthew 
Published: December 2020

AbstractOver 250 million people suffer from schistosomiasis, a tropical disease caused by parasitic flatworms known as schistosomes. Humans become infected by free-swimming, water-borne larvae, which penetrate the skin. The earliest intra-mammalian stage, called the schistosomulum, undergoes a series of developmental transitions. These changes are critical for the parasite to adapt to its new environment as it navigates through host tissues to reach its niche, where it will grow to reproductive maturity. Unravelling the mechanisms that drive intra-mammalian development requires knowledge of the spatial organisation and transcriptional dynamics of different cell types that comprise the schistomulum body. To fill these important knowledge gaps, we perform single-cell RNA sequencing on two-day old schistosomula of Schistosoma mansoni. We identify likely gene expression profiles for muscle, nervous system, tegument, oesophageal gland, parenchymal/primordial gut cells, and stem cells. In addition, we validate cell markers for all these clusters by in situ hybridisation in schistosomula and adult parasites. Taken together, this study provides a comprehensive cell-type atlas for the early intra-mammalian stage of this devastating metazoan parasite.
Molecular basis for RNA polymerase-dependent transcription complex recycling by the helicase-like motor protein HelD
Authors: Newing Timothy P. , Oakley Aaron J. , Miller Michael , Dawson Catherine J. , Brown Simon H. J. , Bouwer James C. , Tolun Gökhan , Lewis Peter J. 
Published: December 2020

AbstractIn bacteria, transcription complexes stalled on DNA represent a major source of roadblocks for the DNA replication machinery that must be removed in order to prevent damaging collisions. Gram-positive bacteria contain a transcription factor HelD that is able to remove and recycle stalled complexes, but it was not known how it performed this function. Here, using single particle cryo-electron microscopy, we have determined the structures of Bacillus subtilis RNA polymerase (RNAP) elongation and HelD complexes, enabling analysis of the conformational changes that occur in RNAP driven by HelD interaction. HelD has a 2-armed structure which penetrates deep into the primary and secondary channels of RNA polymerase. One arm removes nucleic acids from the active site, and the other induces a large conformational change in the primary channel leading to removal and recycling of the stalled polymerase, representing a novel mechanism for recycling transcription complexes in bacteria.
Mycobacterial HelD is a nucleic acids-clearing factor for RNA polymerase
Authors: Kouba Tomáš , Koval’ Tomáš , Sudzinová Petra , Pospíšil Jiří , Brezovská Barbora , Hnilicová Jarmila , Šanderová Hana , Janoušková Martina , Šiková Michaela , Halada Petr , Sýkora Michal , Barvík Ivan , Nováček Jiří , Trundová Mária , Dušková Jarmila , Skálová Tereza , Chon URee , Murakami Katsuhiko S. , Dohnálek Jan , Krásný Libor 
Published: December 2020

AbstractRNA synthesis is central to life, and RNA polymerase (RNAP) depends on accessory factors for recovery from stalled states and adaptation to environmental changes. Here, we investigated the mechanism by which a helicase-like factor HelD recycles RNAP. We report a cryo-EM structure of a complex between the Mycobacterium smegmatis RNAP and HelD. The crescent-shaped HelD simultaneously penetrates deep into two RNAP channels that are responsible for nucleic acids binding and substrate delivery to the active site, thereby locking RNAP in an inactive state. We show that HelD prevents non-specific interactions between RNAP and DNA and dissociates stalled transcription elongation complexes. The liberated RNAP can either stay dormant, sequestered by HelD, or upon HelD release, restart transcription. Our results provide insights into the architecture and regulation of the highly medically-relevant mycobacterial transcription machinery and define HelD as a clearing factor that releases RNAP from nonfunctional complexes with nucleic acids.
The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling
Authors: Pei Hao-Hong , Hilal Tarek , Chen Zhuo A. , Huang Yong-Heng , Gao Yuan , Said Nelly , Loll Bernhard , Rappsilber Juri , Belogurov Georgiy A. , Artsimovitch Irina , Wahl Markus C. 
Published: December 2020

AbstractCellular RNA polymerases (RNAPs) can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, but how RNAP recycling into active states is achieved remains elusive. In Bacillus subtilis, the RNAP δ subunit and NTPase HelD have been implicated in RNAP recycling. We structurally analyzed Bacillus subtilis RNAP-δ-HelD complexes. HelD has two long arms: a Gre cleavage factor-like coiled-coil inserts deep into the RNAP secondary channel, dismantling the active site and displacing RNA, while a unique helical protrusion inserts into the main channel, prying the β and β′ subunits apart and, aided by δ, dislodging DNA. RNAP is recycled when, after releasing trapped nucleic acids, HelD dissociates from the enzyme in an ATP-dependent manner. HelD abundance during slow growth and a dimeric (RNAP-δ-HelD)2 structure that resembles hibernating eukaryotic RNAP I suggest that HelD might also modulate active enzyme pools in response to cellular cues.