bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction-disorder-driven characteristic momentum in graphene, approach of multi-body distribution functions
Authors: Najafi M. N. 
Published: March 2019

AbstractMulti-point probability measures along with the dielectric function of Dirac Fermions in mono-layer graphene containing particle-particle and white-noise (out-plane) disorder interactions on an equal footing in the Thomas-Fermi-Dirac approximation is investigated. By calculating the one-body carrier density probability measure of the graphene sheet, we show that the density fluctuation (ζ−1) is related to the disorder strength (ni), the interaction parameter (rs) and the average density ($$\bar{{\boldsymbol{n}}}$$

n
¯

) via the relation $${{\boldsymbol{\zeta }}}^{-{\bf{1}}}{\boldsymbol{\propto }}{{\boldsymbol{r}}}_{{\boldsymbol{s}}}{{\boldsymbol{n}}}_{{\boldsymbol{i}}}^{{\bf{2}}}{\bar{{\boldsymbol{n}}}}^{-{\bf{1}}}$$

ζ

−
1

∝

r

s

n

i

2

n
¯

−
1

for which $$\bar{{\boldsymbol{n}}}\to {\bf{0}}$$

n
¯

→
0
leads to strong density inhomogeneities, i.e. electron-hole puddles (EHPs), in agreement with the previous works. The general equation governing the two-body distribution probability is obtained and analyzed. We present the analytical solution for some limits which is used for calculating density-density response function. We show that the resulting function shows power-law behaviors in terms of ζ with fractional exponents which are reported. The disorder-averaged polarization operator is shown to be a decreasing function of momentum like ordinary 2D parabolic band systems. It is seen that a disorder-driven momentum qch emerges in the system which controls the behaviors of the screened potential. We show that in small densities an instability occurs in which imaginary part of the dielectric function becomes negative and the screened potential changes sign. Corresponding to this instability, some oscillations in charge density along with a screening-anti-screening transition are observed. These effects become dominant in very low densities, strong disorders and strong interactions, the state in which EHPs appear. The total charge probability measure is another quantity which has been investigated in this paper. The resulting equation is analytically solved for large carrier densities, which admits the calculation of arbitrary-point correlation function.
Statistics of thermomagnetic breakdown in Nb superconducting films
Authors: Blanco Alvarez S. , Brisbois J. , Melinte S. , Kramer R. B. G. , Silhanek A. V. 
Published: March 2019

AbstractSuperconductors are well known for their ability to screen out magnetic fields. In type-II superconductors, as the magnetic field pressure is progressively increased, magnetic flux accumulates at the periphery of the sample, very much like charges accumulate in a capacitor when voltage is increased. As for capacitors, exceeding certain threshold field causes the blocked magnetic flux to abruptly penetrate into the sample. This phenomenon, triggered by a thermomagnetic instability, is somewhat analogous to the dielectric breakdown of the capacitor and leaves behind a similar Lichtenberg imprinting. Even though electrical breakdown threshold has been extensively studied in dielectrics, little information is known about the statistical distribution of the thermomagnetic breakdown in superconductors. In this work, we address this problem by performing magneto-optical imaging experiments on a Nb film where nanometric heating elements are used to rapidly erase the magnetic history of the sample. We demonstrate that the size and shape distributions of avalanches permits to unambiguously identify the transition between two regimes where either thermal diffusivity or magnetic diffusivity dominates. Clear criteria for discriminating athermal dynamic avalanches from thermally driven avalanches are introduced. This allows us to provide the first precise determination of the threshold field of the thermomagnetic breakdown and unveil the details of the transition from finger-like magnetic burst to dendritic branching morphology. These findings open a new avenue in the interdisciplinary exploration of catastrophic avalanches through non destructive repeatable experiments.
Temporal variability of diazotroph community composition in the upwelling region off NW Iberia
Authors: Moreira-Coello Víctor , Mouriño-Carballido Beatriz , Marañón Emilio , Fernández-Carrera Ana , Bode Antonio , Sintes Eva , Zehr Jonathan P. , Turk-Kubo Kendra , Varela Marta M. 
Published: March 2019

AbstractKnowledge of the ecology of N2-fixing (diazotrophic) plankton is mainly limited to oligotrophic (sub)tropical oceans. However, diazotrophs are widely distributed and active throughout the global ocean. Likewise, relatively little is known about the temporal dynamics of diazotrophs in productive areas. Between February 2014 and December 2015, we carried out 9 one-day samplings in the temperate northwestern Iberian upwelling system to investigate the temporal and vertical variability of the diazotrophic community and its relationship with hydrodynamic forcing. In downwelling conditions, characterized by deeper mixed layers and a homogeneous water column, non-cyanobacterial diazotrophs belonging mainly to nifH clusters 1G (Gammaproteobacteria) and 3 (putative anaerobes) dominated the diazotrophic community. In upwelling and relaxation conditions, affected by enhanced vertical stratification and hydrographic variability, the community was more heterogeneous vertically but less diverse, with prevalence of UCYN-A (unicellular cyanobacteria, subcluster 1B) and non-cyanobacterial diazotrophs from clusters 1G and 3. Oligotyping analysis of UCYN-A phylotype showed that UCYN-A2 sublineage was the most abundant (74%), followed by UCYN-A1 (23%) and UCYN-A4 (2%). UCYN-A1 oligotypes exhibited relatively low frequencies during the three hydrographic conditions, whereas UCYN-A2 showed higher abundances during upwelling and relaxation. Our findings show the presence of a diverse and temporally variable diazotrophic community driven by hydrodynamic forcing in an upwelling system.
Evolutionary constraints on the complexity of genetic regulatory networks allow predictions of the total number of genetic interactions
Authors: Campos Adrian I. , Freyre-González Julio A. 
Published: March 2019

AbstractGenetic regulatory networks (GRNs) have been widely studied, yet there is a lack of understanding with regards to the final size and properties of these networks, mainly due to no network currently being complete. In this study, we analyzed the distribution of GRN structural properties across a large set of distinct prokaryotic organisms and found a set of constrained characteristics such as network density and number of regulators. Our results allowed us to estimate the number of interactions that complete networks would have, a valuable insight that could aid in the daunting task of network curation, prediction, and validation. Using state-of-the-art statistical approaches, we also provided new evidence to settle a previously stated controversy that raised the possibility of complete biological networks being random and therefore attributing the observed scale-free properties to an artifact emerging from the sampling process during network discovery. Furthermore, we identified a set of properties that enabled us to assess the consistency of the connectivity distribution for various GRNs against different alternative statistical distributions. Our results favor the hypothesis that highly connected nodes (hubs) are not a consequence of network incompleteness. Finally, an interaction coverage computed for the GRNs as a proxy for completeness revealed that high-throughput based reconstructions of GRNs could yield biased networks with a low average clustering coefficient, showing that classical targeted discovery of interactions is still needed.
Self-organized criticality in geophysical turbulence
Authors: Smyth W. D. , Nash J. D. , Moum J. N. 
Published: March 2019

AbstractTurbulence in geophysical flows tends to organize itself so that the mean flow remains close to a stability boundary in parameter space. That characteristic suggests self-organized criticality (SOC), a statistical property that has been identified in a range of complex phenomena including earthquakes, forest fires and solar flares. This note explores the relationship between the properties of forced, sheared, stratified turbulence (as found in oceans, atmospheres and other geophysical fluids) and those of SOC. Self-organization to the critical state is demonstrated in a wide range of cases drawn mostly (but not entirely) from in situ observations of ocean turbulence. Turbulent events in the ocean also exhibit a second characteristic associated with SOC: their sizes follow a power-law distribution indicating self-similarity. These results suggest SOC as a new conceptual foundation for the study of geophysical turbulence, an explanation for the mixing efficiency of ocean turbulence and a potential for cross-fertilization with other areas of geophysics.
Voltage-induced strain clocking of nanomagnets with perpendicular magnetic anisotropies
Authors: Wang Qianchang , Hu Jin-Zhao , Liang Cheng-Yen , Sepulveda Abdon , Carman Greg 
Published: March 2019

AbstractNanomagnetic logic (NML) has attracted attention during the last two decades due to its promise of high energy efficiency combined with non-volatility. Data transmission in NML relies on Bennett clocking through dipole interaction between neighboring nanomagnetic bits. This paper uses a fully coupled finite element model to simulate Bennett clocking based on strain-mediated multiferroic system for Ni, CoFeB and Terfenol-D with perpendicular magnetic anisotropies. Simulation results demonstrate that Terfenol-D system has the highest energy efficiency, which is 2 orders of magnitude more efficient than Ni and CoFeB. However, the high efficiency is associated with switching incoherency due to its large magnetostriction coefficient. It is also suggested that the CoFeB clocking system has lower bit-density than in Ni or Terfenol-D systems due to its large dipole coupling. Moreover, we demonstrate that the precessional perpendicular switching and the Bennett clocking can be achieved using the same strain-mediated multiferroic architecture with different voltage pulsing. This study opens new possibilities to an all-spin in-memory computing system.
Identification of Novel Inhibitors of DLK Palmitoylation and Signaling by High Content Screening
Authors: Martin Dale D. O. , Kanuparthi Prasad S. , Holland Sabrina M. , Sanders Shaun S. , Jeong Hey-Kyeong , Einarson Margret B. , Jacobson Marlene A. , Thomas Gareth M. 
Published: March 2019

AbstractAfter axonal insult and injury, Dual leucine-zipper kinase (DLK) conveys retrograde pro-degenerative signals to neuronal cell bodies via its downstream target c-Jun N-terminal kinase (JNK). We recently reported that such signals critically require modification of DLK by the fatty acid palmitate, via a process called palmitoylation. Compounds that inhibit DLK palmitoylation could thus reduce neurodegeneration, but identifying such inhibitors requires a suitable assay. Here we report that DLK subcellular localization in non-neuronal cells is highly palmitoylation-dependent and can thus serve as a proxy readout to identify inhibitors of DLK palmitoylation by High Content Screening (HCS). We optimized an HCS assay based on this readout, which showed highly robust performance in a 96-well format. Using this assay we screened a library of 1200 FDA-approved compounds and found that ketoconazole, the compound that most dramatically affected DLK localization in our primary screen, dose-dependently inhibited DLK palmitoylation in follow-up biochemical assays. Moreover, ketoconazole significantly blunted phosphorylation of c-Jun in primary sensory neurons subjected to trophic deprivation, a well known model of DLK-dependent pro-degenerative signaling. Our HCS platform is thus capable of identifying novel inhibitors of DLK palmitoylation and signalling that may have considerable therapeutic potential.
Distal interphalangeal joint extensor tendon enthesopathy in patients with nail psoriasis
Authors: Krajewska-Włodarczyk Magdalena , Owczarczyk-Saczonek Agnieszka , Placek Waldemar , Wojtkiewicz Maja , Wiktorowicz Andrzej , Wojtkiewicz Joanna 
Published: March 2019

AbstractThe aim of the study was an ultrasound assessment of distal interphalangeal (DIP) joint enthesopathy in patients with nail psoriasis. Altogether, 72 patients with nail psoriasis (41 with psoriasis and 31 with psoriatic arthritis) and 30 people in the control group participated in the study. In total, 1014 nails were examined. The thickness of DIP digital extensor tendons in the groups of patients with psoriasis (Ps) and psoriatic arthritis (PsA) was correlated with the nail bed thickness (r = 0.316, p = 0.027 vs. r = 0.402, p = 0.031, respectively) and with the thickness of the nail matrix in patients with psoriasis (r = 0.421, p = 0.012). The linear regression model showed the tendon thickness in Ps patients to be affected by the nail bed thickness, duration of psoriasis and the thickness of the nail matrix, whereas in PsA patients it was found to be significantly affected by duration of psoriasis and of arthritis, the nail bed thickness, CRP concentration and the swollen joint count. Our findings may indicate the role of the nail-tendon apparatus changes in the PsA development and they emphasise the justifiability of US examinations in patients with psoriasis direct assessment of morphological changes in nails as potential predictors of PsA development.
Severe wildfire exposes remnant peat carbon stocks to increased post-fire drying
Authors: Kettridge N. , Lukenbach M. C. , Hokanson K. J. , Devito K. J. , Petrone R. M. , Mendoza C. A. , Waddington J. M. 
Published: March 2019

AbstractThe potential of high severity wildfires to increase global terrestrial carbon emissions and exacerbate future climatic warming is of international concern. Nowhere is this more prevalent than within high latitude regions where peatlands have, over millennia, accumulated legacy carbon stocks comparable to all human CO2 emissions since the beginning of the industrial revolution. Drying increases rates of peat decomposition and associated atmospheric and aquatic carbon emissions. The degree to which severe wildfires enhance drying under future climates and induce instability in peatland ecological communities and carbon stocks is unknown. Here we show that high burn severities increased post-fire evapotranspiration by 410% within a feather moss peatland by burning through the protective capping layer that restricts evaporative drying in response to low severity burns. High burn severities projected under future climates will therefore leave peatlands that dominate dry sub-humid regions across the boreal, on the edge of their climatic envelopes, more vulnerable to intense post-fire drying, inducing high rates of carbon loss to the atmosphere that amplify the direct combustion emissions.
Improving maize grain yield by matching maize growth and solar radiation
Authors: Yang Yunshan , Xu Wenjuan , Hou Peng , Liu Guangzhou , Liu Wanmao , Wang Yonghong , Zhao Rulang , Ming Bo , Xie Ruizhi , Wang Keru , Li Shaokun 
Published: March 2019

AbstractMatching of maize growth with solar radiation is of great importance for achieving high yield. We conducted experiments using different maize cultivars and planting densities under different solar radiations during grain filling to quantitatively analyze the relationships among these factors. We found that a decrease in solar radiation after silking caused a drop in maize grain yield and biomass, with lower solar radiation intensities leading to worse grain yields and biomass. Cultivar ZD958 was more sensitive to solar radiation changes than cultivar XY335; slight decreases in solar radiation (i.e., 15% shading) caused significant declines in ZD958 grain yield. When total solar radiation during grain filling was less than 486.9 MJ m−2 for XY335 and less than 510.9 MJ m−2 for ZD958, the two cultivars demonstrated high yields at lower planting density of 7.5 × 104 plants ha−1; average yields were 13.36 and 11.09 Mg ha−1, respectively. When radiation intensities were higher than 549.5 MJ m−2 for XY335 and higher than 605.8 MJ m−2 for ZD958, yields were higher at a higher planting density of 12 × 104 plants ha−1, with average yields of 20.58 Mg ha−1 for XY335 and 19.65 Mg ha−1 for ZD958.
A Novel Graphene Metal Semi-Insulator Semiconductor Transistor and Its New Super-Low Power Mechanism
Authors: Li Ping , Zeng R. Z. , Liao Y. B. , Zhang Q. W. , Zhou J. H. 
Published: March 2019

AbstractThe state-of-art Si Matel-Oxide-Semiconductor Field-Effect-Transistor (MOS-FET) meets the problem of the Power Consumption (PC) can not be effecively deceased guided by the Moore’s Law as before. The GFET has the problem of the device can not be effectively turned off, since the band-gap of the graphene is zero. To solve these problems, noticing the amount of the carriers in the 2 dementional semiconductor material is limited, we propose a Matel-Semi-Insulator-Semiconductor Field-Effect-Transistor (MSIS-FET) to replace the traditional MOS-FET. We verify our idea by fabricating the graphene MSIS-FETs using the natural Aluminium-oxide (Al-oxide) as the semi-insulator gate dielectric. From MSIS-FETs fabricated, we obtain following experimental results. The graphene MSIS-FET is turned off very well, a recorded high Ids on/off ratio of 5 × 107 is achieved. A saddle and close-loop shape transfer feature of Ids-Vgs is obtained first time for transistors. A non-volatile memory characteristics is observed. A carrier re-injection principle and a super-Low PC mechanism for semiconductor devices and integrated circuits (ICs) are found from the transfer feature of the graphene MSIS-FET. It is shown that the PC of the semiconductor devices and (ICs) can be reduced by over three orders of magnitude by using this new mechanism.
Coarsening Behavior of Particles in Fe-O-Al-Ca Melts
Authors: Wang Linzhu , Li Junqi , Yang Shufeng , Chen Chaoyi , Jin Huixin , Li Xiang 
Published: March 2019

AbstractThe characteristics of particles greatly affect the microstructure and performance of metallic materials, especially their sizes. To provide insight into coarsening phenomena of particles in metallic melts, Fe-O-Al-Ca melt with calcium aluminate particles was selected as a model system. This study uses HT-CSLM, SEM detections and stereological analysis to probe the behavior of particles and their characteristics including size, number density, volume fraction, spreading of particle size, inter-surface distance and distribution of particles. Based on the experimental evidence and calculation of collision, we demonstrate that the coarsening of inclusion particles is not only dependent on the Ostwald growth as studied in previous study, but also on the particle coagulation, and floatation. The collision of particles affects the maximum size of the particles during whole deoxidation process and dominates the coarsening of particles at later stage of deoxidation under the condition without external stirring in Fe-O-Al-Ca melts. The factors influencing collision behaviors and floating properties were also analyzed, which is corresponding to coarsening behavior and change of particle characteristic in the melts with different amounts of Ca addition. Such coarsening mechanism may also be useful in predicting the size of particles in other metallic materials.
Bacillus Calmette-Guérin Induces PD-L1 Expression on Antigen-Presenting Cells via Autocrine and Paracrine Interleukin-STAT3 Circuits
Authors: Copland Alastair , Sparrow Adam , Hart Peter , Diogo Gil Reynolds , Paul Mathew , Azuma Miyuki , Reljic Rajko 
Published: March 2019

AbstractBacillus Calmette-Guérin (BCG) is the only licensed vaccine for tuberculosis (TB), and is also used as an immunotherapy for bladder cancer and other malignancies due to its immunostimulatory properties. Mycobacteria spp., however, are well known for their numerous immune evasion mechanisms that limit the true potential of their therapeutic use. One such major mechanism is the induction of programmed death ligand-1 (PD-L1), which mitigates adaptive immune responses. Here, we sought to unravel the molecular pathways behind PD-L1 up-regulation on antigen-presenting cells (APCs) by BCG. We found that infection of APCs with BCG induced PD-L1 up-regulation, but that this did not depend on direct infection, suggesting a soluble mediator for this effect. BCG induced potent quantities of IL-6 and IL-10, and the downstream transcription factor STAT3 was hyper-phosphorylated. Intracellular analyses revealed that levels of PD-L1 molecules were associated with the STAT3 phosphorylation state, suggesting a causal link. Neutralisation of the IL-6 or IL-10 cytokine receptors dampened STAT3 phosphorylation and BCG-mediated up-regulation of PD-L1 on APCs. Pharmacological inhibition of STAT3 achieved the same effect, confirming an autocrine-paracrine cytokine loop as a mechanism for BCG-mediated up-regulation of PD-L1. Finally, an in vivo immunisation model showed that BCG vaccination under PD-L1 blockade could enhance antigen-specific memory CD4 T-cell responses. These novel findings could lead to refinement of BCG as both a vaccine for infectious disease and as a cancer immunotherapy.
The different influences of drought stress at the flowering stage on rice physiological traits, grain yield, and quality
Authors: Yang Xiaolong , Wang Benfu , Chen Liang , Li Ping , Cao Cougui 
Published: March 2019

AbstractSeasonal drought is a major threat to rice production. However, the sensitivity of rice to drought stress (DS) at different growth periods remains unclear. The objective of this study was to reveal the different impacts of DS at the flowering stage on rice physiological traits, grain yield, and quality. Field experiments were conducted with two rice cultivars, Yangliangyou 6 (YLY6) and Hanyou 113 (HY113) under two water treatments (traditional flooding (CK) and DS at flowering stage) in 2013 and 2014. Compared with CK, grain yield (GY) under DS was significantly reduced by 23.2% for YLY6 and 24.0% for HY113 while instantaneous water use efficiency (IWUE) was significantly increased by 39% for YLY6 and 37% for HY113, respectively. All physiological traits were significantly decreased under DS and physiological activities did not revert to normal levels at grain filling stage. There was no significant effect on the appearance and nutritional quality except for the significant increase in chalky kernel and chalkiness under DS. Our data suggest that drought stress at flowering stage has a strong influence on rice physiological traits and yield. Stronger recovery capability contributes to maintaining relatively high grain production, which could be a great target for the breeder in developing drought-tolerant rice cultivars.
Details of hydrophobic entanglement between small molecules and Braun’s lipoprotein within the cavity of the bacterial chaperone LolA
Authors: Boags Alister , Samsudin Firdaus , Khalid Syma 
Published: March 2019

AbstractThe cell envelope of Gram-negative bacteria is synthesized and maintained via mechanisms that are targets for development of novel antibiotics. Here we focus on the process of moving Braun’s lipoprotein (BLP) from the periplasmic space to the outer membrane of E. coli, via the LolA protein. In contrast to current thinking, we show that binding of multiple inhibitor molecules inside the hydrophobic cavity of LolA does not prevent subsequent binding of BLP inside the same cavity. Rather, based on our atomistic simulations we propose the theory that once inhibitors and BLP are bound inside the cavity of LolA, driven by hydrophobic interactions, they become entangled with each other. Our umbrella sampling calculations show that on the basis of energetics, it is more difficult to dislodge BLP from the cavity of LolA when it is uncomplexed compared to complexed with inhibitor. Thus the inhibitor reduces the affinity of BLP for the LolA cavity.