bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of compatibilizer on morphology and properties of HDPE/Nylon 6 blends
Authors: Feng Jingxing , Zhang Guojun , MacInnis Kari , Li Zhenpeng , Olah Andrew , Baer Eric
Published: January 2019

The compatibilization effect of linear low‐density polyethylene‐grafted maleic anhydride (LLDPEgMA) and high‐density polyethylene‐grafted maleic anhydride (HDPEgMA) on high‐density polyethylene (HDPE)/polyamide 6 (Nylon 6) blend system is investigated. The morphology of 45 wt %/55 wt % polyethylene/Nylon 6 blends with three compatibilizer compositions (5 wt %, 10 wt %, and 15 wt %) are characterized by atomic force microscopic (AFM) phase imaging. The blend with 5 wt % LLDPEgMA demonstrates a Nylon 6 continuous, HDPE dispersed morphology. Increased amount of LLDPEgMA leads to sharp transition in morphology to HDPE continuous, Nylon 6 dispersed morphology. Whereas, increasing HDPEgMA concentration in the same blends results in gradual morphology transition from Nylon 6 continuous to co‐continuous morphology. The mechanical properties, oxygen permeability, and water vapor permeability are measured on the blends which confirm the morphology and indicate that HDPEgMA is a better compatibilizer than LLDPEgMA for the HDPE/Nylon 6 blend system. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 281–290
Calculations of adsorption energies, coadsorptions, and diffusion barriers of H atoms, and the H2 formation on a nanographene surface (coronene)
Authors: Sánchez Morella , Ruette Fernando
Published: January 2019

Adsorption and diffusion of ortho, meta, and para cis hydrogen dimers, on central and edge rings of coronene (nanographene), were studied by using the DFT‐D method, considering different multiplicities. Calculated values of adsorption energy, coadsorption energy, diffusion barriers, and reaction barriers for the H2 formation (Langmuir‐Hinshelwood (LH) mechanism) were evaluated for ortho and para locations. The adsorption of an •H atom increases the adsorption energy of another hydrogen (coadsorption). The most stable dimers are those where an •H is adsorbed on hydrogenated‐edge sites. Dimers with multiplicity M = 1, with •H separated by an odd number of bonds, have higher coadsorption energies (higher diffusion barriers) than those where the separation is by an even number. The H2 formation is more feasible on edge‐edge and edge‐center sites; however, on ortho hydrogenated‐edge sites, it is not energetically favored. For M = 3, H2 formation is not observed because desorption of •H occurs.
Coupled‐cluster singles, doubles and perturbative triples with density fitting approximation for massively parallel heterogeneous platforms
Authors: Peng Chong , Calvin Justus A. , Valeev Edward F.
Published: January 2019

A high‐performance implementation of the coupled‐cluster singles, doubles, and perturbative triples [CCSD(T)] is developed in the Massively Parallel Quantum Chemistry program. Novel features include: (1) reduced memory requirements via a density‐fitting (DF) CCSD implementation utilizing distributed lazy evaluation for tensors with more than two unoccupied indices and (2) the ability to utilize efficiently many‐core nodes (Intel Xeon Phi) and heterogeneous nodes with multiple NVIDIA GPUs on each node. All data that are greater than quadratic in the system size are distributed among processes. Excellent strong scaling is observed on distributed‐memory computers equipped with conventional CPUs, Intel Xeon Phi processors, and heterogeneous nodes with multiple NVIDIA GPUs Canonical CCSD(T) energies can be evaluated for systems containing 200 electrons and 1000 basis functions in a few days using a small size commodity cluster, with even larger computations possible on leadership‐class computing resources.
Adsorption and diffusion of alkali‐atoms (Li, Na, and K) on BeN dual doped graphene
Authors: Ullah Saif , Denis Pablo A. , Sato Fernando
Published: January 2019

We employ first‐principles DFT calculations to explore the potential use of BeN dual doped graphene (DDG) as an anode material for alkali‐based batteries. The introduction of BeN in graphene raise the adsorption of Li, Na, and K by 1.37 eV (2.23 times), 1.23 eV (2.83 times), and 1.14 eV (2.14 times), respectively. Furthermore, BeN DDG offers a modest energy barrier for alkali atoms studied. Moreover, the alkali atoms have good chemistry with Be and the interaction strength decreases during the migration toward N. Most importantly, the exceptional storage capacity of BeN DDG for Li (~2255 mAh/g), Na (~996 mAh/g), and K (~747 mAh/g) makes it a highly desirable anode material. Additionally, the average open circuit voltage offered for Li (0.66 V), Na (0.33 V), and (K = 1.10 V) is found to be in excellent range. All these outstanding properties provide the possibility of using BeN DDG in future alkali‐based batteries.
Can lipid removal affect interpretation of resource partitioning from stable isotopes in Southern Ocean pteropods?
Authors: Weldrick Christine K. , Trebilco Rowan , Swadling Kerrie M.
Published: January 2019

Rationale

Stable isotope analysis (SIA) is a powerful tool to estimate dietary links between polar zooplankton. However, the presence of highly variable 12C‐rich lipids may skew estimations as they are depleted in 13C relative to proteins and carbohydrates, consequently masking carbon signals from food sources. Lipid effects on pteropod‐specific values requires examining, since accounting for lipids is rarely conducted among the few existing pteropod‐related SIA studies. It is currently unclear whether lipid correction is necessary prior to SIA of pteropods.

Methods

Whole bodies of three species of pteropods (Clio pyramidata f. sulcata, Clione limacina antarctica, and Spongiobranchaea australis) sampled from the Southern Ocean were lipid‐extracted chemically to test the effects on δ13C and δ15N values (n = 38 individuals in total). We determined the average change in δ13C values for each treatment, and compared this offset with those from published normalization models. We tested lipid correction effects on isotopic niche dispersion metrics to compare interpretations surrounding food web dynamics.

Results

Pteropods with lipids removed had δ13C values up to 4.5‰ higher than bulk samples. However, lipid extraction also produced higher δ15N values than bulk samples. Isotopic niche overlaps between untreated pteropods and their potential food sources were significantly different from overlaps generated between lipid‐corrected pteropods and their potential food sources. Data converted using several published normalization models did not reveal significant differences among various calculated niche metrics, including standard ellipse and total area.

Conclusions

We recommend accounting for lipids via chemical extraction or mathematical normalization before applying SIA to calculate ecological niche metrics, particularly for organisms with moderate to high lipid content such as polar pteropods. Failure to account for lipids may result in misinterpretations of niche dimensions and overlap and, consequently, trophic interactions.
Modular covariance and uniqueness of $$ J\overline{T} $$ deformed CFTs
Authors: Aharony Ofer , Datta Shouvik , Giveon Amit , Jiang Yunfeng , Kutasov David
Published: January 2019

Abstract

We study families of two dimensional quantum field theories, labeled by a dimensionful parameter μ, that contain a holomorphic conserved U(1) current J(z). We assume that these theories can be consistently defined on a torus, so their partition sum, with a chemical potential for the charge that couples to J, is modular covariant. We further require that in these theories, the energy of a state at finite μ is a function only of μ, and of the energy, momentum and charge of the corresponding state at μ = 0, where the theory becomes conformal. We show that under these conditions, the torus partition sum of the theory at μ = 0 uniquely determines the partition sum (and thus the spectrum) of the perturbed theory, to all orders in μ, to be that of a

$$ \mu J\overline{T} $$

μ
J

T
¯

deformed conformal field theory (CFT). We derive a flow equation for the

$$ J\overline{T} $$

J

T
¯

deformed partition sum, and use it to study non-perturbative effects. We find non-perturbative ambiguities for any non-zero value of μ, and comment on their possible relations to holography.
Modular invariance and uniqueness of $$ T\overline{T} $$ deformed CFT
Authors: Aharony Ofer , Datta Shouvik , Giveon Amit , Jiang Yunfeng , Kutasov David
Published: January 2019

Abstract

Any two dimensional quantum field theory that can be consistently defined on a torus is invariant under modular transformations. In this paper we study families of quantum field theories labeled by a dimensionful parameter t, that have the additional property that the energy of a state at finite t is a function only of t and of the energy and momentum of the corresponding state at t = 0, where the theory becomes conformal. We show that under this requirement, the partition sum of the theory at t = 0 uniquely determines the partition sum (and thus the spectrum) of the perturbed theory, to all orders in t, to be that of a

$$ T\overline{T} $$

T

T
¯

deformed CFT. Non-perturbatively, we find that for one sign of t (for which the energies are real) the partition sum is uniquely determined, while for the other sign we find non-perturbative ambiguities. We characterize these ambiguities and comment on their possible relations to holography.
Aspects of massive gauge theories on three sphere in infinite mass limit
Authors: Shimizu Kazuma
Published: January 2019

Abstract

We study the S
3 partition function of three-dimensional supersymmetric

$$ \mathcal{N}=4 $$

N
=
4

U(N) SQCD with massive matter multiplets in the infinite mass limit with the so-called Coulomb branch localization. We show that in the infinite mass limit a specific point of the Coulomb branch is selected and contributes dominantly to the partition function. Therefore, we can argue whether each multiplet included in the theory is effectively massless in this limit, even on S
3, and conclude that the partition function becomes that of the effective theory on the specific point of the Coulomb branch in the infinite mass limit. In order to investigate which point of the Coulomb branch is dominant, we use the saddle point approximation in the large N limit because the solution of the saddle point equation can be regarded as a specific point of the Coulomb branch. Then, we calculate the partition functions for small rank N and confirm that their behaviors in the infinite mass limit are consistent with the conjecture from the results in the large N limit. Our result suggests that the partition function in the infinite mass limit corresponds to that of an interacting superconformal field theory.
Mass spectrum of 2-dimensional $$ \mathcal{N}=\left(2,2\right) $$ super Yang-Mills theory on the lattice
Authors: August D. , Steinhauser M. , Wellegehausen B. H. , Wipf A.
Published: January 2019

Abstract

In the present work we analyse

$$ \mathcal{N}=\left(2,2\right) $$

N
=

2
2

supersymmetric Yang-Mills (SYM) theory with gauge group SU(2) in two dimensions by means of lattice simulations. The theory arises as dimensional reduction of

$$ \mathcal{N}=1 $$

N
=
1

SYM theory in four dimensions. As in other gauge theories with extended supersymmetry, the classical scalar potential has flat directions which may destabilize numerical simulations. In addition, the fermion determinant need not be positive and this sign-problem may cause further problems in a stochastic treatment. We demonstrate that

$$ \mathcal{N}=\left(2,2\right) $$

N
=

2
2

super Yang-Mills theory has actually no sign problem and that the flat directions are lifted and thus stabilized by quantum corrections. Only the bare masses of the scalars experience a finite additive renormalization in this finite theory. On various lattices with different lattice constants we determine the scalar masses and hopping parameters for which the supersymmetry violating terms are minimal. By studying four Ward identities and by monitoring the π-mass we show that supersymmetry is indeed restored in the continuum limit. In the second part we calculate the masses of the low-lying bound states. We find that in the infinite-volume and supersymmetric continuum limit the Veneziano-Yankielowicz super-multiplet becomes massless and the Farrar-Gabadadze-Schwetz super-multiplet decouples from the theory. In addition, we estimate the masses of the excited mesons in the Veneziano-Yankielowicz multiplet. We observe that the gluino-glueballs have comparable masses to the excited mesons.
RETRACTED ARTICLE: A study on user
recognition using 2D ECG based on ensemble of deep convolutional neural
networks
Authors: Kim Min-Gu , Ko Hoon , Pan Sung Bum
Published: January 2019

The risk of tampering exists for conventional user recognition methods
based on biometrics such as face and fingerprint. Recently, research on user
recognition using biometric signals such as electrocardiogram (ECG),
electroencephalogram (EEG), and electromyogram (EMG) has been actively performed to
overcome this issue. We herein propose a user recognition method applying a deep
learning technique based on ensemble networks after transforming ECG signals into
two-dimensional (2D) images. A preprocessing process for one-dimensional ECG signals
is performed to remove noise or distortion; subsequently, they are projected onto a
2D image space and transformed into image data. For the proposed algorithm, we
designed deep learning-based ensemble networks to improve the degraded performance
arising from overfitting in a single network. Our experimental results demonstrate
that the proposed ensemble networks exhibit an accuracy that is 1.7% higher than
that of the single network. In particular, the performance of the ensemble networks
is up to 13% higher compared to the single network that degrades the recognition
rate by displaying similar features between classes.
Community‐Level Responses to Iron Availability in Open Ocean Plankton Ecosystems
Authors: Caputi Luigi , Carradec Quentin , Eveillard Damien , Kirilovsky Amos , Pelletier Eric , Pierella Karlusich Juan J. , Rocha Jimenez Vieira Fabio , Villar Emilie , Chaffron Samuel , Malviya Shruti , Scalco Eleonora , Acinas Silvia G. , Alberti Adriana , Aury Jean‐Marc , Benoiston Anne‐Sophie , Bertrand Alexis , Biard Tristan , Bittner Lucie , Boccara Martine , Brum Jennifer R. , Brunet Christophe , Busseni Greta , Carratalà Anna , Claustre Hervé , Coelho Luis Pedro , Colin Sébastien , D'Aniello Salvatore , Da Silva Corinne , Del Core Marianna , Doré Hugo , Gasparini Stéphane , Kokoszka Florian , Jamet Jean‐Louis , Lejeusne Christophe , Lepoivre Cyrille , Lescot Magali , Lima‐Mendez Gipsi , Lombard Fabien , Lukeš Julius , Maillet Nicolas , Madoui Mohammed‐Amin , Martinez Elodie , Mazzocchi Maria Grazia , Néou Mario B. , Paz‐Yepes Javier , Poulain Julie , Ramondenc Simon , Romagnan Jean‐Baptiste , Roux Simon , Salvagio Manta Daniela , Sanges Remo , Speich Sabrina , Sprovieri Mario , Sunagawa Shinichi , Taillandier Vincent , Tanaka Atsuko , Tirichine Leila , Trottier Camille , Uitz Julia , Veluchamy Alaguraj , Veselá Jana , Vincent Flora , Yau Sheree , Kandels‐Lewis Stefanie , Searson Sarah , Dimier Céline , Picheral Marc ,   Tara Oceans Coordinators, Bork Peer , Boss Emmanuel , de Vargas Colomban , Follows Michael J. , Grimsley Nigel , Guidi Lionel , Hingamp Pascal , Karsenti Eric , Sordino Paolo , Stemmann Lars , Sullivan Matthew B. , Tagliabue Alessandro , Zingone Adriana , Garczarek Laurence , d'Ortenzio Fabrizio , Testor Pierre , Not Fabrice , d'Alcalà Maurizio Ribera , Wincker Patrick , Bowler Chris , Iudicone Daniele
Published: January 2019

Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio‐oceanographic and bio‐omics data sets fromTaraOceans in the context of the iron products from two state‐of‐the‐art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large‐scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment.
Geology and Fluid Discharge at Dorado Outcrop, a Low Temperature Ridge‐Flank Hydrothermal System
Authors: Wheat C. Geoffrey , Hartwell Anne M. , McManus James , Fisher Andrew T. , Orcutt Beth N. , Schlicht Lucy E. M. , Niedenzu Sara , Bach Wolfgang
Published: January 2019

Two expeditions to Dorado Outcrop on the eastern flank of the East Pacific Rise and west of the Middle America Trench collected images, video, rocks, and sediment samples and measured temperature and fluid discharge rates to document the physical and biogeochemical characteristics of a regional, low‐temperature (~15 °C) hydrothermal system. Analysis of video and images identified lava morphologies: pillow, lobate, and sheet flows. Glasses from collected lavas were consistent with an off‐axis formation. Hydrothermal discharge generally occurs through pillow lavas but is patchy, sporadic, and sometimes ceases at particular sites of discharge. Yearlong temperature measurements at five of these discharge sites show daily ranges that oscillate with tidal frequencies by 6 °C or more. Instantaneous fluid discharge rates (0.16 to 0.19 L/s) were determined resulting in a calculated discharge of ~200 L/s when integrated over the area defined by the most robust fluid discharge. Such discharge has a power output of 10–12 MW. Hydrothermal seepage through thin sediment adjacent to the outcrop accounts for <3% of this discharge, but seepage may support an oxic sediment column. High extractable Mn concentrations and depleted δ13C in the low but variable organic solid phase suggest that hydrothermal fluids provide a source for manganese accumulation and likely enhance the oxidation of organic carbon. Comparisons of the physical and geochemical characteristics at Dorado and Baby Bare Outcrops, the latter being the only other site of ridge‐flank hydrothermal discharge that has been sampled directly, suggest commonalities and differences that have implications for future discoveries.
D‐Region High‐Latitude Forcing Factors
Authors: Macotela Edith L. , Clilverd Mark , Manninen Jyrki , Moffat‐Griffin Tracy , Newnham David A. , Raita Tero , Rodger Craig J.
Published: January 2019

The subionospheric very low frequency (VLF) radio wave technique provides the possibility of investigating the response of the ionospheric D‐region to a diversity of transient and long‐term physical phenomena originating from above (e.g., energetic particle precipitation) and from below (e.g., atmospheric waves). In this study, we identify the periodicities that appear in VLF measurements and investigate how they may be related to changes in space weather and atmospheric activity. The powerful VLF signal transmitted from NAA (24 kHz) on the east coast of the United States, and received at Sodankylä, Finland, was analyzed. Wavelet transform, wavelet power spectrum, wavelet coherence, and cross‐wavelet spectrum were computed for daily averages of selected ionospheric, space weather, and atmospheric parameters from November 2008 until June 2018. Our results show that the significant VLF periods that appear during solar cycle 24 are the annual oscillation, semiannual oscillation, 121‐day, 86‐day, 61‐day, and solar rotation oscillations. We found that the annual oscillation corresponds to variability in mesospheric temperature and solar Lyman‐α (Ly‐α) flux and the semiannual oscillation to variability in space weather‐related parameters. The solar rotation oscillation observed in the VLF variability is mainly related to the Ly‐α flux variation at solar maximum and to geomagnetic activity variation during the declining phase of the solar cycle. Our results are important since they strengthen our understanding of the Earth's D‐region response to solar and atmospheric forcing.
Strain Localization and Weakening Processes in Viscously Deforming Rocks: Numerical Modeling Based on Laboratory Torsion Experiments
Authors: Döhmann M. J. E. A. , Brune S. , Nardini L. , Rybacki E. , Dresen G.
Published: January 2019

Localization processes in the viscous lower crust generate ductile shear zones over a broad range of scales affecting long‐term lithosphere deformation and the mechanical response of faults during the seismic cycle. Here we use centimeter‐scale numerical models in order to gain detailed insight into the processes involved in strain localization and rheological weakening in viscously deforming rocks. Our 2‐D Cartesian models are benchmarked to high‐temperature and high‐pressure torsion experiments on Carrara marble samples containing a single weak Solnhofen limestone inclusion. The models successfully reproduce bulk stress‐strain transients and final strain distributions observed in the experiments by applying a simple, first‐order softening law that mimics rheological weakening. We find that local stress concentrations forming at the inclusion tips initiate strain localization inside the host matrix. At the tip of the propagating shear zone, weakening occurs within a process zone, which expands with time from the inclusion tips toward the matrix. Rheological weakening is a precondition for shear zone localization, and the width of this shear zone is found to be controlled by the degree of softening. Introducing a second softening step at elevated strain, a high strain layer develops inside the localized shear zone, analogous to the formation of ultramylonite bands in mylonites. These results elucidate the transient evolution of stress and strain rate during inception and maturation of ductile shear zones.
Inadvertent Localized Intensification of Precipitation by Aircraft
Authors: Moisseev Dmitri , Lautaportti Susanna , Alku Laura , Tabakova Ksenia , O'Connor Ewan J. , Leskinen Matti , Kulmala Markku
Published: January 2019

Eleven years of dual‐polarization weather radar data, complemented by satellite and lidar observations, were used to investigate the origin of areas of localized intensification of precipitation spotted in the vicinity of Helsinki‐Vantaa airport. It was observed that existing precipitation is enhanced locally on spatial scales from a few kilometers to several tens of kilometers. The precipitation intensity in these localized areas was 6–14 times higher than the background large‐scale precipitation rate. Surface observations and dual‐polarization radar data indicate that snowflakes within the ice portion of the falling precipitation in the intensification regions are larger and more isotropic than in the surrounding precipitation. There appears to be an increase in the ice particle number concentration within the intensification region. The observed events were linked to arriving or departing air traffic. We advocate that the mechanism responsible for intensification is aircraft‐produced ice particles boosting the aggregation growth of snowflakes.
Formation of Central Pits in Impact Craters on Mars: A Statistical Investigation of Proposed Mechanisms
Authors: Peel Samantha E. , Burr Devon M. , Tran Liem
Published: January 2019

Central pit craters (CPCs) are complex craters that exhibit depressions within their floors or central uplifts. Some proposed models for central pit formation can be grouped by similar mechanism: (A) explosive volatile release, (B) central peak collapse, and (C) drainage of subsurface melted volatiles. We test these groups of mechanisms for central pit formation on Mars based on morphometries expected from each mechanism. Volatiles in the target (A and C) would be expected to result in a correlation with layered ejecta, also formed from volatiles, for CPCs over non‐CPCs. Central peak collapse (B) should result in larger diameters for pit rims than central peaks due to outward flow. Explosive volatile release (A) should yield smaller volumes for pit rims than pits due to mass loss. Data were collected on Context Camera images and digital elevation models for random samples of CPCs to assess the presence of these expected morphologies. Results of a Fisher exact test showed no preference in layered ejecta with CPCs over non‐CPCs, inconsistent with volatiles in the target. Results of an independent t test showed that central pit rim diameters are larger than central peak diameters, supporting some component of central peak collapse, although measurement uncertainty makes this interpretation tentative. Central pit rim volumes were not found to be statistically smaller than their pits, weighing against formation by explosive volatile release. Thus, our findings do not support any single group of formation mechanism tested here, although they allow for formation by some combination of these (or other) processes.
Formation of Complex Craters in Layered Targets With Material Anisotropy
Authors: Hopkins Ryan T. , Osinski Gordon R. , Collins Gareth S.
Published: January 2019

Meteorite impacts often occur in layered targets, where the strength of the target varies as a function of depth, but this complexity is often not represented in numerical impact simulations because of the high computational cost of resolving thin layers. To address this limitation, we developed a method to approximate the effect of multiple thin weak layers within a sedimentary sequence using a single material layer to represent the entire sequence. Our approach, implemented in the iSALE (impact‐Simplified Arbitrary Lagrangian Eulerian) shock physics code, combines an anisotropic yield criterion with a cell‐based method to track the orientation of layers. To demonstrate the efficacy of the method and constrain parameters of the anisotropic strength model required to replicate the effects of thin, weak layers, we compare results of simulations of an ~20‐ to 25‐km diameter complex crater on Earth using the new method to those from simulations that explicitly resolve multiple thin weak layers. We show that our approach allows for a reduction in computational cost, negating the need for an increase in spatial resolution to resolve thin layers in the target, while replicating crater formation and final morphology from the high‐resolution models. In keeping with field observations, we also find that anisotropic layers may be responsible for a lack of central uplift expression observed at many craters formed in targets with thick sedimentary layers (e.g., the Haughton and Ries impact structures).
How Ningaloo Ni�o Supercharges the El Ni�o–Southern Oscillation
Authors: Underwood Emily
Published: January 2019

The warm current cools the tropical Pacific and strengthens trade winds.
Federal Government Shutdown Stings Scientists and Science
Authors: Showstack Randy
Published: January 2019

Scientists say the shutdown is a message that the government considers science nonessential.
RETRACTED ARTICLE: Rifaximin alters gut microbiota profile, but does not affect systemic inflammation - a randomized controlled trial in common variable immunodeficiency
Authors: Jørgensen S. F. , Macpherson M. E. , Bjørnetrø T. , Holm K. , Kummen M. , Rashidi A. , Michelsen A. E. , Lekva T. , Halvorsen B. , Trøseid M. , Mollnes T. E. , Berge R. K. , Yndestad A. , Ueland T. , Karlsen T. H. , Aukrust P. , Hov J. R. , Fevang B.
Published: January 2019

Common variable immunodeficiency (CVID) patients have reduced gut microbial diversity compared to healthy controls. The reduced diversity is associated with gut leakage, increased systemic inflammation and ten “key” bacteria that capture the gut dysbiosis (dysbiosis index) in CVID. Rifaximin is a broad-spectrum non-absorbable antibiotic known to reduce gut leakage (lipopolysaccharides, LPS) in liver disease. In this study, we explored as a ‘proof of concept’ that altering gut microbial composition could reduce systemic inflammation, using CVID as a disease model. Forty adult CVID patients were randomized, (1:1) to twice-daily oral rifaximin 550 mg versus no treatment for 2 weeks in an open-label, single-centre study. Primary endpoints were reduction in plasma/serum levels of soluble (s) CD14, sCD25, sCD163, neopterin, CRP, TNF, LPS and selected cytokines measured at 0, 2 and 8 weeks. Secondary endpoint was changes in intra-individual bacterial diversity in stool samples. Rifaximin-use did not significantly change any of the inflammation or gut leakage markers, but decreased gut microbial diversity compared with no treatment (p = 0.002). Importantly, the gut bacteria in the CVID dysbiosis index were not changed by rifaximin. The results suggest that modulating gut microbiota by rifaximin is not the chosen intervention to affect systemic inflammation, at least not in CVID.
Royal jelly peptides: potential inhibitors of β-secretase in N2a/APP695swe cells
Authors: Zhang Xueqing , Yu Yi , Sun Ping , Fan Zhen , Zhang Wensheng , Feng Chengqiang
Published: January 2019

Royal jelly (RJ) is a type of natural health product with a long history of use. Royal jelly peptides (RJPs) obtained from RJ have numerous bioactivities. To study the neuroprotective effect of RJPs, major royal jelly proteins were digested into crude RJPs and subsequently purified by RP-HPLC. Purified RJP fractions were evaluated in N2a/APP695swe cells. Our results indicated that purified royal jelly peptides (RJPs) (1–9 μg/mL) could inhibit external beta-amyloid 40 (Aβ1-40) and beta-amyloid 42 (Aβ1-42) production through the down-regulation of β-secretase (BACE1) in N2a/APP695 cells. The modulation of BACE1 may be related to histone acetylation modification. Our results demonstrated a neuroprotective function of RJPs, which indicates that RJPs may serve as potential β-secretase inhibitors in ameliorating Aβ-related pathology in Alzheimer’s Disease.
Central place foragers select ocean surface convergent features despite differing foraging strategies
Authors: Oliver Matthew J. , Kohut Josh T. , Bernard Kim , Fraser William , Winsor Peter , Statscewich Hank , Fredj Erick , Cimino Megan , Patterson-Fraser Donna , Carvalho Filipa
Published: January 2019

Discovering the predictors of foraging locations can be challenging, and is often the critical missing piece for interpreting the ecological significance of observed movement patterns of predators. This is especially true in dynamic coastal marine systems, where planktonic food resources are diffuse and must be either physically or biologically concentrated to support upper trophic levels. In the Western Antarctic Peninsula, recent climate change has created new foraging sympatry between Adélie (Pygoscelis adeliae) and gentoo (P. papua) penguins in a known biological hotspot near Palmer Deep canyon. We used this recent sympatry as an opportunity to investigate how dynamic local oceanographic features affect aspects of the foraging ecology of these two species. Simulated particle trajectories from measured surface currents were used to investigate the co-occurrence of convergent ocean features and penguin foraging locations. Adélie penguin diving activity was restricted to the upper mixed layer, while gentoo penguins often foraged much deeper than the mixed layer, suggesting that Adélie penguins may be more responsive to dynamic surface convergent features compared to gentoo penguins. We found that, despite large differences in diving and foraging behavior, both shallow-diving Adélie and deeper-diving gentoo penguins strongly selected for surface convergent features. Furthermore, there was no difference in selectivity for shallow- versus deep-diving gentoo penguins. Our results suggest that these two mesopredators are selecting surface convergent features, however, how these surface signals are related to subsurface prey fields is unknown.
Windshield wipers on connected vehicles produce high-accuracy rainfall maps
Authors: Bartos Matthew , Park Hyongju , Zhou Tian , Kerkez Branko , Vasudevan Ramanarayan
Published: January 2019

Connected vehicles are poised to transform the field of environmental sensing by enabling acquisition of scientific data at unprecedented scales. Drawing on a real-world dataset collected from almost 70 connected vehicles, this study generates improved rainfall estimates by combining weather radar with windshield wiper observations. Existing methods for measuring precipitation are subject to spatial and temporal uncertainties that compromise high-precision applications like flash flood forecasting. Windshield wiper measurements from connected vehicles correct these uncertainties by providing precise information about the timing and location of rainfall. Using co-located vehicle dashboard camera footage, we find that wiper measurements are a stronger predictor of binary rainfall state than traditional stationary gages or radar-based measurements. We introduce a Bayesian filtering framework that generates improved rainfall estimates by updating radar rainfall fields with windshield wiper observations. We find that the resulting rainfall field estimate captures rainfall events that would otherwise be missed by conventional measurements. We discuss how these enhanced rainfall maps can be used to improve flood warnings and facilitate real-time operation of stormwater infrastructure.
PD-1/PD-L1 Pathway Modulates Macrophage Susceptibility to Mycobacterium tuberculosis Specific CD8+ T cell Induced Death
Authors: Suarez Guadalupe Verónica , Melucci Ganzarain Claudia del Carmen , Vecchione María Belén , Trifone César Ariel , Marín Franco José Luis , Genoula Melanie , Moraña Eduardo José , Balboa Luciana , Quiroga Maria Florencia
Published: January 2019

CD8+T cells contribute to tuberculosis (TB) infection control by inducing death of infected macrophages. Mycobacterium tuberculosis (Mtb) infection is associated with increased PD-1/PD-L1 expression and alternative activation of macrophages. We aimed to study the role of PD-1 pathway and macrophage polarization on Mtb-specific CD8+T cell-induced macrophage death. We observed that both PD-L1 on CD14+ cells and PD-1 on CD8+T cells were highly expressed at the site of infection in pleurisy TB patients’ effusion samples (PEMC). Moreover, a significant increase in CD8+T cells’ Mtb-specific degranulation from TB-PEMC vs. TB-PBMC was observed, which correlated with PD-1 and PDL-1 expression. In an in vitro model, M1 macrophages were more susceptible to Mtb-specific CD8+T cells’ cytotoxicity compared to M2a macrophages and involved the transfer of cytolytic effector molecules from CD8+T lymphocytes to target cells. Additionally, PD-L1 blocking significantly increased the in vitro Ag-specific CD8+T cell cytotoxicity against IFN-γ-activated macrophages but had no effect over cytotoxicity on IL-4 or IL-10-activated macrophages. Interestingly, PD-L1 blocking enhanced Mtb-specific CD8+ T cell killing of CD14+ cells from human tuberculous pleural effusion samples. Our data indicate that PD-1/PD-L1 pathway modulates antigen-specific cytotoxicity against M1 targets in-vitro and encourage the exploration of checkpoint blockade as new adjuvant for TB therapies.
A novel tankyrase inhibitor, MSC2504877, enhances the effects of clinical CDK4/6 inhibitors
Authors: Menon Malini , Elliott Richard , Bowers Leandra , Balan Nicolae , Rafiq Rumana , Costa-Cabral Sara , Munkonge Felix , Trinidade Ines , Porter Roderick , Campbell Andrew D. , Johnson Emma R. , Esdar Christina , Buchstaller Hans-Peter , Leuthner Birgitta , Rohdich Felix , Schneider Richard , Sansom Owen , Wienke Dirk , Ashworth Alan , Lord Christopher J.
Published: January 2019

Inhibition of the PARP superfamily tankyrase enzymes suppresses Wnt/β-catenin signalling in tumour cells. Here, we describe here a novel, drug-like small molecule inhibitor of tankyrase MSC2504877 that inhibits the growth of APC mutant colorectal tumour cells. Parallel siRNA and drug sensitivity screens showed that the clinical CDK4/6 inhibitor palbociclib, causes enhanced sensitivity to MSC2504877. This tankyrase inhibitor-CDK4/6 inhibitor combinatorial effect is not limited to palbociclib and MSC2504877 and is elicited with other CDK4/6 inhibitors and toolbox tankyrase inhibitors. The addition of MSC2504877 to palbociclib enhances G1 cell cycle arrest and cellular senescence in tumour cells. MSC2504877 exposure suppresses the upregulation of Cyclin D2 and Cyclin E2 caused by palbociclib and enhances the suppression of phospho-Rb, providing a mechanistic explanation for these effects. The combination of MSC2504877 and palbociclib was also effective in suppressing the cellular hyperproliferative phenotype seen in Apc defective intestinal stem cells in vivo. However, the presence of an oncogenic Kras p.G12D mutation in mice reversed the effects of the MSC2504877/palbociclib combination, suggesting one molecular route that could lead to drug resistance.
Thermopriming reprograms metabolic homeostasis to confer heat tolerance
Authors: Serrano Natalia , Ling Yu , Bahieldin Ahmed , Mahfouz Magdy M.
Published: January 2019

Heat stress threatens agriculture worldwide. Plants acquire heat stress tolerance through priming, which establishes stress memory during mild or severe transient heat stress. Such induced thermotolerance restructures metabolic networks and helps maintain metabolic homeostasis under heat stress. Here, we used an electrospray ionization mass spectrometry-based platform to explore the composition and dynamics of the metabolome of Arabidopsis thaliana under heat stress and identify metabolites involved in thermopriming. Primed plants performed better than non-primed plants under severe heat stress due to altered energy pathways and increased production of branched-chain amino acids, raffinose family oligosaccharides (RFOs), lipolysis products, and tocopherols. These metabolites serve as osmolytes, antioxidants and growth precursors to help plants recover from heat stress, while lipid metabolites help protect membranes against heat stress. The carbohydrate (e.g., sucrose and RFOs) and lipid superpathway metabolites showed the most significant increases. Under heat stress, there appears to be crosstalk between carbohydrate metabolism (i.e., the thermomemory metabolites stachyose, galactinol, and raffinose) and tyrosine metabolism towards the production of the thermomemory metabolite salidroside, a phenylethanoid glycoside. Crosstalk occurs between two glycerophospholipid pathways (the biosynthetic pathways of the thermomemory metabolite S-adenosyl-L-homocysteine and the terpenoid backbone) and the δ-tocopherol (chloroplast lipid) pathway, which favors the production of glycine betaine and other essential tocopherols, respectively, compounds which are essential for abiotic stress tolerance in plants. Therefore, metabolomic analysis can provide comprehensive insights into the metabolites involved in stress responses, which could facilitate plant breeding to maximize crop yields under adverse conditions.
Monitoring glycosylation metabolism in brain and breast cancer by Raman imaging
Authors: Kopec M. , Imiela A. , Abramczyk H.
Published: January 2019

We have shown that Raman microspectroscopy is a powerful method for visualization of glycocalyx offering cellular interrogation without staining, unprecedented spatial and spectral resolution, and biochemical information. We showed for the first time that Raman imaging can be used to distinguish successfully between glycosylated and nonglycosylated proteins in normal and cancer tissue. Thousands of protein, lipid and glycan species exist in cells and tissues and their metabolism is monitored via numerous pathways, networks and methods. The metabolism can change in response to cellular environment alterations, such as development of a disease. Measuring such alterations and understanding the pathways involved are crucial to fully understand cellular metabolism in cancer development. In this paper Raman markers of glycogen, glycosaminoglycan, chondroitin sulfate, heparan sulfate proteoglycan were identified based on their vibrational signatures. High spatial resolution of Raman imaging combined with chemometrics allows separation of individual species from many chemical components present in each cell. We have found that metabolism of proteins, lipids and glycans is markedly deregulated in breast (adenocarcinoma) and brain (medulloblastoma) tumors. We have identified two glycoforms in the normal breast tissue and the malignant brain tissue in contrast to the breast cancer tissue where only one glycoform has been identified.
Heparan Sulfate Mimetics: A New Way to Optimize Therapeutic Effects of Hydrogel-Embedded Mesenchymal Stromal Cells in Colonic Radiation-Induced Damage
Authors: Moussa Lara , Demarquay Christelle , Réthoré Gildas , Benadjaoud Mohamed Amine , Siñeriz Fernando , Pattapa Girish , Guicheux Jérôme , Weiss Pierre , Barritault Denis , Mathieu Noëlle
Published: January 2019

Clinical expression of gastrointestinal radiation toxicity on non-cancerous tissue could be very life threatening and clinicians must deal increasingly with the management of late side effects of radiotherapy. Cell therapy, in particular mesenchymal stromal cell (MSC) therapy, has shown promising results in numerous preclinical animal studies and thus has emerged as a new hope for patient refractory to current treatments. However, many stem cell clinical trials do not confer any beneficial effect suggesting a real need to accelerate research towards the successful clinical application of stem cell therapy. In this study, we propose a new concept to improve the procedure of MSC-based treatment for greater efficacy and clinical translatability. We demonstrated that heparan sulfate mimetic (HS-m) injections that restore the extracellular matrix network and enhance the biological activity of growth factors, associated with local injection of MSC protected in a hydrogel, that increase cell engraftment and cell survival, improve the therapeutic benefit of MSC treatment in two animal models relevant of the human pathology. For the first time, a decrease of the injury score in the ulcerated area was observed with this combined treatment. We also demonstrated that the combined treatment favored the epithelial regenerative process. In this study, we identified a new way, clinically applicable, to optimize stem-cell therapy and could be proposed to patients suffering from severe colonic defect after radiotherapy.
Increasing the resolution of the reconstructed image in terahertz pulse time-domain holography
Authors: Balbekin Nikolay S. , Kulya Maksim S. , Belashov Andrey V. , Gorodetsky Andrei , Petrov Nikolay V.
Published: January 2019

In this paper, we present a novel numerical approach for increasing the resolution of retrieved images of objects after their diffraction patterns are recorded via terahertz pulse time-domain holography (THz PTDH). THz PTDH allows for spectrally resolved imaging with high spatial resolution and does not require the fine alignment of complex optics in the THz path. The proposed data post-processing method opens up the possibility to reconstruct holograms recorded with spatially restricted THz detectors, and overcome the diffraction limit even for the lower-frequency spectral components. The method involves an iterative procedure of backward-forward wavefront propagation to simulate the field distribution beyond the initially recorded hologram area. We show significant improvement in both the object reconstruction and contrast across the whole spectrum, with qualitative resolution enhancement at lower frequency spectral components.
The Phenolic compound Kaempferol overcomes 5-fluorouracil resistance in human resistant LS174 colon cancer cells
Authors: Riahi-Chebbi Ichrak , Souid Soumaya , Othman Houcemeddine , Haoues Meriam , Karoui Habib , Morel Alain , Srairi-Abid Najet , Essafi Makram , Essafi-Benkhadir Khadija
Published: January 2019

Resistance to 5-Fluorouracil chemotherapy is a major cause of therapeutic failure in colon cancer cure. Development of combined therapies constitutes an effective strategy to inhibit cancer cells and prevent the emergence of drug resistance. For this purpose, we investigated the anti-tumoral effect of thirteen phenolic compounds, from the Tunisian quince Cydonia oblonga Miller, alone or combined to 5-FU, on the human 5-FU-resistant LS174-R colon cancer cells in comparison to parental cells. Our results showed that only Kaempferol was able to chemo-sensitize 5-FU-resistant LS174-R cells. This phenolic compound combined with 5-FU exerted synergistic inhibitory effect on cell viability. This combination enhanced the apoptosis and induced cell cycle arrest of both chemo-resistant and sensitive cells through impacting the expression levels of different cellular effectors. Kaempferol also blocked the production of reactive oxygen species (ROS) and modulated the expression of JAK/STAT3, MAPK, PI3K/AKT and NF-κB. In silico docking analysis suggested that the potent anti-tumoral effect of Kaempferol, compared to its two analogs (Kaempferol 3-O-glucoside and Kampferol 3-O-rutinoside), can be explained by the absence of glucosyl groups. Overall, our data propose Kaempferol as a potential chemotherapeutic agent to be used alone or in combination with 5-FU to overcome colon cancer drug resistance.
Human TNF-Luc reporter mouse: A new model to quantify inflammatory responses
Authors: Minshawi Faisal , White Mike R. H. , Muller Werner , Humphreys Neil , Jackson Dean , Campbell Barry J. , Adamson Antony , Papoutsopoulou Stamatia
Published: January 2019

Tumour necrosis factor (TNF) is a key cytokine during inflammatory responses and its dysregulation is detrimental in many inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease. Here, we used a bacterial artificial chromosome (BAC) construct that expresses luciferase under the control of the humanTNFlocus to generate a novel transgenic mouse, the hTNF.LucBAC strain.In vitrostimulation of hTNF.LucBAC cells of different origin revealed a cell specific response to stimuli demonstrating the integrated construct’s ability as a proxy for inflammatory gene response. Lipopolysaccharide was the most potent luciferase inducer in macrophages, while TNF was a strong activator in intestinal organoids. Lipopolysaccharide-induced luciferase activity in macrophages was downregulated by inhibitors of NF-κB pathway, as well as by Interleukin-10, a known anti-inflammatory cytokine. Moreover, the transgene-dependent luciferase activity showed a positive correlation to the endogenous murine soluble TNF secreted to the culture medium. In conclusion, the hTNF.LucBAC strain is a valuable tool for studying and screening molecules that target TNF synthesis and will allow further functional studies of the regulatory elements of theTNFlocus.