bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complex Deformation of Central and North China Through Pn Velocity and Anisotropy Tomography
Authors: Lü Yan , Xu Yihe , Liu Jiaqi , He Yuhui , Zhang Jinhai 
Published: December 2019

AbstractUsing our recently developed Pn tomography method, we obtain high‐resolution Pn velocity and anisotropy structures of uppermost mantle beneath the Central and North China, which provide useful insight concerning the mechanism of intraplate mantle dynamics. The consistency between the new Pn model and seismic reflection/refraction profiles demonstrates the high quality of our model. Based on the Pn anisotropy structure surrounding the Alxa Block, we infer that material extrusion from northeastern Tibet was impeded and turned to the west and south edges of the Alxa Block. The Pn structures beneath the Sichuan Basin and Songpan‐Ganzi Orogen suggest that the stable Sichuan Basin impeded material extrusion from the Tibetan Plateau and caused material from Tibet to be extruded separately along the west and northwest edges of the Sichuan Basin. To the north of the Sichuan Basin, we infer that the extrusion has ceased within the Songpan‐Ganzi Orogen rather than to further east. The high Pn velocities beneath the Qinling Orogen do not support the proposal of large‐scale eastward material escaping flow in the shallow mantle beneath the western Qinling Orogen. The Pn velocity distribution beneath the North China Craton indicates that hot material from the mantle is more likely to upwell beneath deep faults or active orogenic areas. Our model indicates that the northern and central parts of the Ordos Block retain stable structures at the uppermost mantle, while its southeastern has been reworked by hot material.
New Zealand‐Wide Geodetic Strain Rates Using a Physics‐Based Approach
Authors: Haines A. John , Wallace Laura M. 
Published: December 2019

AbstractWe present a new strain rate map for New Zealand, based on geodetic data acquired from 1995 to 2013. We use a physics‐based approach, which inverts the horizontal GPS velocities for Vertical Derivatives of Horizontal Stress (VDoHS) rates, relying on using elasticity theory and the horizontal force balance equations at the Earth's surface. The VDoHS rates are then integrated to obtain horizontal strain rates. Strain rates derived using this new approach are less spatially smoothed than previous results using conventional methods. In addition to the major plate boundary features in New Zealand, low‐rate zones of deformation are resolved by the strain and VDoHS rates, which bodes well for the utility of this method to reveal processes on hidden or ill‐characterized fault zones. Application of this new method to obtain strain and VDoHS rates provides the highest resolution view to‐date of contemporary deformation in New Zealand.
Elongation and Stability of a Linear Dune
Authors: Rozier Olivier , Narteau Clément , Gadal Cyril , Claudin Philippe , Courrech du Pont Sylvain 
Published: December 2019

AbstractCompared to barchan dunes, the morphodynamics of linear dunes that elongate on a nonerodible bed have barely been investigated by means of laboratory experiments or numerical simulations. Using a cellular automaton model, we study the elongation of a solitary linear dune from a sand source and show that it can reach a steady state. This steady state is analyzed to understand the physical processes at work along the dune. Crest reversals together with avalanche processes control the shape of transverse sections. Dune width and height decrease almost linearly with distance downstream until the minimum size for dune is reached. This is associated with a constant sand loss along the dune, which eventually compensates for the sediment influx and sets the dune length. This sand budget is discussed to distinguish an elongating linear dune from a barchan dune and to explain the complexity of linear dune fields in nature.
The Northwestern Greenland Ice Sheet During The Early Pleistocene Was Similar To Today
Authors: Christ Andrew J. , Bierman Paul R. , Knutz Paul C. , Corbett Lee B. , Fosdick Julie C. , Thomas Elizabeth K. , Cowling Owen C. , Hidy Alan J. , Caffee Marc W. 
Published: December 2019

AbstractThe multi‐million year history of the Greenland Ice Sheet remains poorly known. Ice‐proximal glacial marine diamict provides a direct but discontinuous record of ice sheet behavior; it is underutilized as a climate archive. Here, we present a novel multiproxy analysis of an Early Pleistocene marine diamict from northwestern Greenland. Low cosmogenic nuclide concentrations indicate minimal near‐surface exposure, similar to modern terrestrial sediment. Detrital apatite (U‐Th‐Sm)/He (AHe) ages all predate glaciation by >150 million years, suggesting the northwestern Greenland Ice Sheet had, by 1.9 Ma, not yet incised fjords of sufficient depth to excavate grains with young AHe ages. The diamict contains terrestrial plant leaf wax, likely from land surfaces surrounding the ice sheet. These data indicate that a persistent, dynamic ice sheet existed in northwestern Greenland by 1.9 Ma and that diamict is a useful archive of ice sheet history and process.
Subauroral Green STEVE Arcs: Evidence for Low‐Energy Excitation
Authors: Mende S. B. , Harding B. J. , Turner C. 
Published: December 2019

AbstractSubauroral emissions known as STEVEs (Strong Thermal Emission Velocity Enhancements) are sometimes accompanied by green arcs containing magnetic field‐aligned “picket fence” structures. In a newly published spectrum of a green picket fence arc Gillies et al. (2019, https://doi.org/10.1029/2019GL083272) showed that the visible emission in such arcs is mostly OI 557.7 nm with minimal N2+ 1N. This finding is consistent with the color ratios found in digital camera photos (Mende & Turner, 2019, https://doi.org/10.1029/2019JA026851) and is distinct from the ratios in auroral precipitation. The spectrum also contains intense N2 first positive (1P) emission. The presence of OI 557.7 (~4.19 eV excitation energy) and N2 1P (~7.35 eV), combined with the lack of N2+ first negative (~18.75 eV) commonly seen in the aurora, suggests that the particles exciting the emission have energy <18.75 eV. This is strong evidence against the precipitation hypothesis recently put forth (Nishimura et al., 2019, https://doi.org/10.1029/2019GL082460; Gillies et al., 2019, https://doi.org/10.1029/2019GL083272).
The Vertical Structure of Liquid Water Content in Shallow Clouds as Retrieved From Dual‐Wavelength Radar Observations
Authors: Zhu Zeen , Lamer Katia , Kollias Pavlos , Clothiaux Eugene E. 
Published: December 2019

AbstractObservations collected over 3 months by the beam‐matched second‐generation Ka/W band Scanning Cloud Radar located at the Atmospheric Radiation Measurement Program Eastern North Atlantic observatory are used to advance existing liquid water content (LWC) retrieval techniques, quantify retrieval uncertainty, and subsequently characterize the impact of cloud dynamics and rain rates on the vertical distribution of LWC in boundary layer clouds both precipitating and broken. A threefold technique is proposed that involves (1) temporally averaging measured radar reflectivities collected at two wavelengths to 30‐s resolution, (2) smoothing via fitting a second‐degree polynomial to their dual‐wavelength ratios within 187.5‐m vertical overlapping sliding windows, and (3) averaging the multiple LWC estimates produced at each height. It is estimated that this technique reduced LWC retrieval uncertainty to 0.10–0.65 g/m3, depending on cloud thickness. Although individual retrievals remained noisy, statistics on subgroups of height‐normalized LWC profiles show that, on average, the vertical distributions of LWC in most of the observed clouds followed a linear relationship with a degree of adiabaticity ranging from 0.6 to 0.2 for 200‐ to 600‐m thick clouds. However, nonlinear LWC profiles were present in subgroups of cloud segments presenting intense (0.1–0.5 mm/hr) drizzle rates where LWC was observed to pool near cloud base and in subgroups of cloud segments within strong (0.6 m/s) downdrafts near cloud top where LWC was coincidently reduced. This nonlinearity is inconsistent with the use of adiabatic cloud assumptions for process studies and supports further development of retrievals like the one proposed.
Extracellular matrix, regional heterogeneity of the aorta, and aortic aneurysm
Authors: Jana Sayantan , Hu Mei , Shen Mengcheng , Kassiri Zamaneh 
Published: December 2019

AbstractAortic aneurysm is an asymptomatic disease with dire outcomes if undiagnosed. Aortic aneurysm rupture is a significant cause of death worldwide. To date, surgical repair or endovascular repair (EVAR) is the only effective treatment for aortic aneurysm, as no pharmacological treatment has been found effective. Aortic aneurysm, a focal dilation of the aorta, can be formed in the thoracic (TAA) or the abdominal (AAA) region; however, our understanding as to what determines the site of aneurysm formation remains quite limited. The extracellular matrix (ECM) is the noncellular component of the aortic wall, that in addition to providing structural support, regulates bioavailability of an array of growth factors and cytokines, thereby influencing cell function and behavior that ultimately determine physiological or pathological remodeling of the aortic wall. Here, we provide an overview of the ECM proteins that have been reported to be involved in aortic aneurysm formation in humans or animal models, and the experimental models for TAA and AAA and the link to ECM manipulations. We also provide a comparative analysis, where data available, between TAA and AAA, and how aberrant ECM proteolysis versus disrupted synthesis may determine the site of aneurysm formation.
Heart failure with preserved ejection fraction: present status and future directions
Authors: Yoon Somy , Eom Gwang Hyeon 
Published: December 2019

AbstractThe clinical importance of heart failure with preserved ejection fraction (HFpEF) has recently become apparent. HFpEF refers to heart failure (HF) symptoms with normal or near-normal cardiac function on echocardiography. Common clinical features of HFpEF include diastolic dysfunction, reduced compliance, and ventricular hypokinesia. HFpEF differs from the better-known HF with reduced ejection fraction (HFrEF). Despite having a “preserved ejection fraction,” patients with HFpEF have symptoms such as shortness of breath, excessive tiredness, and limited exercise capability. Furthermore, the mortality rate and cumulative survival rate are as severe in HFpEF as they are in HFrEF. While beta-blockers and renin-angiotensin-aldosterone system modulators can improve the survival rate in HFrEF, no known therapeutic agents show similar effectiveness in HFpEF. Researchers have examined molecular events in the development of HFpEF using small and middle-sized animal models. This review discusses HFpEF with regard to etiology and clinical features and introduces the use of mouse and other animal models of human HFpEF.
Improvement in indices of cellular protection after psychological treatment for social anxiety disorder
Authors: Månsson Kristoffer N. T. , Lindqvist Daniel , Yang Liu L. , Svanborg Cecilia , Isung Josef , Nilsonne Gustav , Bergman-Nordgren Lise , El Alaoui Samir , Hedman-Lagerlöf Erik , Kraepelien Martin , Högström Jens , Andersson Gerhard , Boraxbekk Carl-Johan , Fischer Håkan , Lavebratt Catharina , Wolkowitz Owen M. , Furmark Tomas 
Published: December 2019

AbstractTelomere attrition is a hallmark of cellular aging and shorter telomeres have been reported in mood and anxiety disorders. Telomere shortening is counteracted by the enzyme telomerase and cellular protection is also provided by the antioxidant enzyme glutathione peroxidase (GPx). Here, telomerase, GPx, and telomeres were investigated in 46 social anxiety disorder (SAD) patients in a within-subject design with repeated measures before and after cognitive behavioral therapy. Treatment outcome was assessed by the Liebowitz Social Anxiety Scale (self-report), administered three times before treatment to control for time and regression artifacts, and posttreatment. Venipunctures were performed twice before treatment, separated by 9 weeks, and once posttreatment. Telomerase activity and telomere length were measured in peripheral blood mononuclear cells and GPx activity in plasma. All patients contributed with complete data. Results showed that social anxiety symptom severity was significantly reduced from pretreatment to posttreatment (Cohen’sd = 1.46). There were no significant alterations in telomeres or cellular protection markers before treatment onset. Telomere length and telomerase activity did not change significantly after treatment, but an increase in telomerase over treatment was associated with reduced social anxiety. Also, lower pretreatment telomerase activity predicted subsequent symptom improvement. GPx activity increased significantly during treatment, and increases were significantly associated with symptom improvement. The relationships between symptom improvement and putative protective enzymes remained significant also after controlling for body mass index, sex, duration of SAD, smoking, concurrent psychotropic medication, and the proportion of lymphocytes to monocytes. Thus, indices of cellular protection may be involved in the therapeutic mechanisms of psychological treatment for anxiety.
Transforming Growth Factor-beta signaling in αβ thymocytes promotes negative selection
Authors: McCarron Mark J. , Irla Magali , Sergé Arnauld , Soudja Saidi M’Homa , Marie Julien C. 
Published: December 2019

AbstractIn the thymus, the T lymphocyte repertoire is purged of a substantial portion of highly self-reactive cells. This negative selection process relies on the strength of TCR-signaling in response to self-peptide-MHC complexes, both in the cortex and medulla regions. However, whether cytokine-signaling contributes to negative selection remains unclear. Here, we report that, in the absence of Transforming Growth Factor beta (TGF-β) signaling in thymocytes, negative selection is significantly impaired. Highly autoreactive thymocytes first escape cortical negative selection and acquire a Th1-like-phenotype. They express high levels of CXCR3, aberrantly accumulate at the cortico-medullary junction and subsequently fail to sustain AIRE expression in the medulla, escaping medullary negative selection. Highly autoreactive thymocytes undergo an atypical maturation program, substantially accumulate in the periphery and induce multiple organ-autoimmune-lesions. Thus, these findings reveal TGF-β in thymocytes as crucial for negative selection with implications for understanding T cell self-tolerance mechanisms.
Design principles of ion selective nanostructured membranes for the extraction of lithium ions
Authors: Razmjou Amir , Asadnia Mohsen , Hosseini Ehsan , Habibnejad Korayem Asghar , Chen Vicki 
Published: December 2019

AbstractIt is predicted that the continuously increasing demand for the energy-critical element of lithium will soon exceed its availability, rendering it a geopolitically significant resource. The present work critically reviews recent reports on Li+ selective membranes. Particular emphasis has been placed on the basic principles of the materials’ design for the development of membranes with nanochannels and nanopores with Li+ selectivity. Fundamental and practical challenges, as well as prospects for the targeted design of Li+ ion-selective membranes are also presented, with the goal of inspiring future critical research efforts in this scientifically and strategically important field.
Enhancing plasticity in central networks improves motor and sensory recovery after nerve damage
Authors: Meyers Eric C. , Kasliwal Nimit , Solorzano Bleyda R. , Lai Elaine , Bendale Geetanjali , Berry Abigail , Ganzer Patrick D. , Romero-Ortega Mario , Rennaker Robert L. , Kilgard Michael P. , Hays Seth A. 
Published: December 2019

AbstractNerve damage can cause chronic, debilitating problems including loss of motor control and paresthesia, and generates maladaptive neuroplasticity as central networks attempt to compensate for the loss of peripheral connectivity. However, it remains unclear if this is a critical feature responsible for the expression of symptoms. Here, we use brief bursts of closed-loop vagus nerve stimulation (CL-VNS) delivered during rehabilitation to reverse the aberrant central plasticity resulting from forelimb nerve transection. CL-VNS therapy drives extensive synaptic reorganization in central networks paralleled by improved sensorimotor recovery without any observable changes in the nerve or muscle. Depleting cortical acetylcholine blocks the plasticity-enhancing effects of CL-VNS and consequently eliminates recovery, indicating a critical role for brain circuits in recovery. These findings demonstrate that manipulations to enhance central plasticity can improve sensorimotor recovery and define CL-VNS as a readily translatable therapy to restore function after nerve damage.
Delay in recovery of the Antarctic ozone hole from unexpected CFC-11 emissions
Authors: Dhomse S. S. , Feng W. , Montzka S. A. , Hossaini R. , Keeble J. , Pyle J. A. , Daniel J. S. , Chipperfield M. P. 
Published: December 2019

AbstractThe Antarctic ozone hole is decreasing in size but this recovery will be affected by atmospheric variability and any unexpected changes in chlorinated source gas emissions. Here, using model simulations, we show that the ozone hole will largely cease to occur by 2065 given compliance with the Montreal Protocol. If the unusual meteorology of 2002 is repeated, an ozone-hole-free-year could occur as soon as the early 2020s by some metrics. The recently discovered increase in CFC-11 emissions of ~ 13 Gg yr−1 may delay recovery. So far the impact on ozone is small, but if these emissions indicate production for foam use much more CFC-11 may be leaked in the future. Assuming such production over 10 years, disappearance of the ozone hole will be delayed by a few years, although there are significant uncertainties. Continued, substantial future CFC-11 emissions of 67 Gg yr−1 would delay Antarctic ozone recovery by well over a decade.
Helix 8 is the essential structural motif of mechanosensitive GPCRs
Authors: Erdogmus Serap , Storch Ursula , Danner Laura , Becker Jasmin , Winter Michaela , Ziegler Nicole , Wirth Angela , Offermanns Stefan , Hoffmann Carsten , Gudermann Thomas , Mederos y Schnitzler Michael 
Published: December 2019

AbstractG-protein coupled receptors (GPCRs) are versatile cellular sensors for chemical stimuli, but also serve as mechanosensors involved in various (patho)physiological settings like vascular regulation, cardiac hypertrophy and preeclampsia. However, the molecular mechanisms underlying mechanically induced GPCR activation have remained elusive. Here we show that mechanosensitive histamine H1 receptors (H1Rs) are endothelial sensors of fluid shear stress and contribute to flow-induced vasodilation. At the molecular level, we observe that H1Rs undergo stimulus-specific patterns of conformational changes suggesting that mechanical forces and agonists induce distinct active receptor conformations. GPCRs lacking C-terminal helix 8 (H8) are not mechanosensitive, and transfer of H8 to non-responsive GPCRs confers, while removal of H8 precludes, mechanosensitivity. Moreover, disrupting H8 structural integrity by amino acid exchanges impairs mechanosensitivity. Altogether, H8 is the essential structural motif endowing GPCRs with mechanosensitivity. These findings provide a mechanistic basis for a better understanding of the roles of mechanosensitive GPCRs in (patho)physiology.
Natural selection favoring more transmissible HIV detected in United States molecular transmission network
Authors: Wertheim Joel O. , Oster Alexandra M. , Switzer William M. , Zhang Chenhua , Panneer Nivedha , Campbell Ellsworth , Saduvala Neeraja , Johnson Jeffrey A. , Heneine Walid 
Published: December 2019

AbstractHIV molecular epidemiology can identify clusters of individuals with elevated rates of HIV transmission. These variable transmission rates are primarily driven by host risk behavior; however, the effect of viral traits on variable transmission rates is poorly understood. Viral load, the concentration of HIV in blood, is a heritable viral trait that influences HIV infectiousness and disease progression. Here, we reconstruct HIV genetic transmission clusters using data from the United States National HIV Surveillance System and report that viruses in clusters, inferred to be frequently transmitted, have higher viral loads at diagnosis. Further, viral load is higher in people in larger clusters and with increased network connectivity, suggesting that HIV in the United States is experiencing natural selection to be more infectious and virulent. We also observe a concurrent increase in viral load at diagnosis over the last decade. This evolutionary trajectory may be slowed by prevention strategies prioritized toward rapidly growing transmission clusters.
Biointerfacial self-assembly generates lipid membrane coated bacteria for enhanced oral delivery and treatment
Authors: Cao Zhenping , Wang Xinyue , Pang Yan , Cheng Shanshan , Liu Jinyao 
Published: December 2019

AbstractThe gut microbiota represents a huge community of microorganisms that play essential roles in immune modulation and homeostasis maintenance. Microbiota transplantation is an important approach to prevent and treat disease as it can inhibit pathogen colonization and positively modulate bacterial composition. However, the development of oral bacterial therapeutics has been restricted by low bioavailability and limited retention in the gastrointestinal tract. Here, we report a simple yet highly efficient method to coat gut microbes via biointerfacial supramolecular self-assembly. Coating can be performed within 15 min by simply vortexing with biocompatible lipids. Bacteria coated with an extra self-assembled lipid membrane exhibit significantly improved survival against environmental assaults and almost unchanged viability and bioactivity. We demonstrate their enhanced efficacies in oral delivery and treatment using two murine models of colitis. We suggest that biointerfacial supramolecular self-assembly may provide a unique platform to generate advanced bacterial therapeutics for the treatment of various diseases.
Microbial Fe(III) reduction as a potential iron source from Holocene sediments beneath Larsen Ice Shelf
Authors: Jung Jaewoo , Yoo Kyu-Cheul , Rosenheim Brad E. , Conway Tim M. , Lee Jae Il , Yoon Ho Il , Hwang Chung Yeon , Yang Kiho , Subt Christina , Kim Jinwook 
Published: December 2019

AbstractRecent recession of the Larsen Ice Shelf C has revealed microbial alterations of illite in marine sediments, a process typically thought to occur during low-grade metamorphism. In situ breakdown of illite provides a previously-unobserved pathway for the release of dissolved Fe2+ to porewaters, thus enhancing clay-rich Antarctic sub-ice shelf sediments as an important source of Fe to Fe-limited surface Southern Ocean waters during ice shelf retreat after the Last Glacial Maximum. When sediments are underneath the ice shelf, Fe2+ from microbial reductive dissolution of illite/Fe-oxides may be exported to the water column. However, the initiation of an oxygenated, bioturbated sediment under receding ice shelves may oxidize Fe within surface porewaters, decreasing dissolved Fe2+ export to the ocean. Thus, we identify another ice-sheet feedback intimately tied to iron biogeochemistry during climate transitions. Further constraints on the geographical extent of this process will impact our understanding of iron-carbon feedbacks during major deglaciations.