bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactoferrin Reduces Necrotizing Enterocolitis Severity by Upregulating Intestinal Epithelial Proliferation
Authors: Liu Jia , Zhu Haitao , Li Bo , Robinson Shaiya C. , Lee Carol , O'Connell Joshua S. , Bindi Edoardo , Zheng Shan , Sherman Philip M. , Pierro Agostino
Published: July 2019

Introduction Necrotizing enterocolitis (NEC) is a devastating intestinal illness in premature infants characterized by severe intestinal inflammation. Despite medical interventions, NEC mortality remains alarmingly high, which necessitates improved therapies. Lactoferrin is among the most abundant proteins in human milk and has important immunomodulatory functions. While previous studies have indicated protective effects of lactoferrin against neonatal sepsis and NEC, the underlying mechanism remains unclear. We hypothesize that lactoferrin downregulates inflammation and upregulates proliferation in intestinal epithelium during NEC injury.

Materials and Methods NEC was induced by hypoxia, gavage feeding of hyperosmolar formula and lipopolysaccharide between postnatal day P5 and P9 (n = 8). Breastfed mice were used as control (n = 7). Lactoferrin (0.3 g/kg/day) was administered once daily by gavage from P6 to P8 in both NEC (NEC + Lac; n = 9) and control mice (Cont + Lac; n = 5). Distal ileum was harvested on P9 and analyzed for disease severity, inflammation, and proliferation. Groups were compared using one-way ANOVA and t-test appropriately; p < 0.05 was considered significant.

Results Compared to NEC group, lactoferrin-treated NEC mice had reduced disease severity, reduced inflammation markers IL-6 and TNF-α expression and increased intestinal stem cell marker Lgr5 + expression. Lactoferrin-treated NEC mice exhibited increased nuclear β-catenin, indicating upregulated Wnt pathway, and increased Ki67 positivity, suggesting enhanced proliferation. Furthermore, lactoferrin administration to control mice did not affect intestinal inflammation as well as Lgr5 + stem cell expression and epithelial proliferation. This supports the safety of lactoferrin administration and indicates that the beneficial effects of lactoferrin are present when intestinal injury such as NEC is present.

Conclusion Lactoferrin administration reduces the intestinal injury in experimental NEC by downregulating inflammation and upregulating cell proliferation. This beneficial effect of lactoferrin in stimulating cell proliferation is mediated by the Wnt pathway. This experimental study provides insights on the mechanism of action of lactoferrin in NEC and the role of lactoferrin in enteral feeding.
Clinical Factors Affecting Condition-Specific Quality-of-Life Domains in Pediatric Patients after Repair of Esophageal Atresia: The Swedish-German EA-QOL Study
Authors: Dellenmark-Blom Michaela , Quitmann Julia , Dingemann Jens , Witt Stefanie , Ure Benno M. , Bullinger Monika , Jönsson Linus , Gatzinsky Vladimir , Dingemann Carmen
Published: July 2019

Introduction We aimed to identify clinical factors affecting condition-specific health related quality of life (HRQOL) domains in children born with esophageal atresia (EA). This can facilitate preventive care to risk groups of HRQOL impairments.

Materials and Methods A total of 124 Swedish and German families of EA children answered the validated EA-QOL questionnaires (response rate 68%), for evaluation of three HRQOL domains in children 2 to 7 years old (53 parents) and four HRQOL domains in children 8 to 17 years old (62 children/71 parents). Clinical data were collected through medical records and a questionnaire. Statistics included between—group analysis, univariable and stepwise multivariable regression analysis, p < 0.05.

Results Between 2 to 7 years, no primary anastomosis (p = 0.022) and female gender (p = 0.026) predicted worse scores related to “physical health and treatment,” and gastrostomy insertion related to “eating” (p = 0.0001), and “social isolation and stress” (p = 0.001). Between 8 to 17 years, no primary anastomosis (child report), prematurity, esophageal dilatation (parent report) predicted poor HRQOL related to “eating” (p < 0.05), associated anomalies to “body perception” (p = 0.031, parent report), female gender (p = 0.018, child report) and severe EA (p = 0.011 child report, p = 0.004 parent report) to “social relationships,” and severe EA predicted worse “health and well-being” scores (p = 0.004, parent report). An increased number of digestive symptoms (difficulty swallowing food, heartburn, and vomiting), lowered all EA-QOL domain scores in both age groups (p < 0.001). An increased number of respiratory problems (cough, wheezing, airway infections. breathlessness, and chest tightness), lowered scores in two HRQOL domains among children 2 to 7 years (p < 0.05).

Conclusion Impairments within condition-specific HRQOL domains in EA children are found in congenital and surgical subgroups, and notably related to digestive symptoms throughout childhood.
Analytical electrolyzer enabling operando characterization of flow plates
Authors: Wheeler Danika G. , Virca Carolyn N. , Berlinguette Curtis P.
Published: July 2019

We present an analytical electrolyzer with sensors embedded within flow plates to enable direct measurement of electrolyte temperatures and pressures in real time during water electrolysis. Flow plates with either parallel or serpentine channels and a total of eight equally spaced sensors were integrated into a flow cell containing a nickel foam gas diffusion layer and an anion exchange membrane. The temperature and pressure of the electrolyte in the channels increase relative to the inlet by as much as 7.3 °C and 11.5 kPa, respectively, during electrolysis at an applied current density of 200 mA cm−2. The measured increases in temperature and pressure differ depending on the flow plate geometry: A greater increase in temperature is observed in parallel flow plates, whereas the serpentine flow plate geometry results in greater variability in pressure. This work represents the first demonstration of an analytical flow cell capable of spatially resolved operando temperature and pressure sensing within the flow channels of a water electrolyzer.
Global weak solutions and long time behavior for 1D compressible MHD equations without resistivity
Authors: Li Yang , Sun Yongzhong
Published: July 2019

We study the initial-boundary value problem for 1D compressible magnetohydrodynamics equations of viscous nonresistive fluids in the Lagrangian mass coordinates. Based on the estimates of upper and lower bounds of the density, weak solutions are constructed by approximation of global regular solutions, the existence of which has recently been obtained by Jiang and Zhang [Nonlinearity 30, 3587–3612 (2017)]. The uniqueness of weak solutions is also proved as a consequence of Lipschitz continuous dependence on the initial data. Furthermore, long time behavior for global solutions is investigated. Specifically, based on the uniform-in-time bounds of the density from above and below away from zero, together with the structure of the equations, we show the exponential decay rate in L2- and H1-norm, respectively, with large initial data.
From discrete Cucker-Smale model to continuous Cucker-Smale model in a temperature field
Authors: Dong Jiu-Gang , Ha Seung-Yeal , Kim Doheon
Published: July 2019

We study emergent dynamics of the discrete and continuous Cucker-Smale (C-S) models in a self-consistent temperature field and provide refined monocluster flocking estimates. More precisely, we present a sufficient framework leading to the monocluster flocking toward the constant common temperature and velocity exponentially fast. This improves the authors’ earlier work where existence of common temperature and velocity are not identified. Our proposed sufficient framework is formulated in terms of the initial data and system parameters. Using the refined flocking, we also provide a uniform-in-time convergence from the discrete model to the continuous model under some suitable compatibility condition on the asymptotic velocities for the discrete and continuous model, as the time step tends to zero. We also provide several numerical examples and compare them with analytical results.
A determinant formula associated with the elliptic hypergeometric integrals of type BC
n
Authors: Ito Masahiko , Noumi Masatoshi
Published: July 2019

We establish a determinant formula for the bilinear form associated with the elliptic hypergeometric integrals of type BCn by studying the structure of q-difference equations to be satisfied by them. The determinant formula is proved by combining the q-difference equations of the determinant and its asymptotic analysis along the singularities. The elliptic interpolation functions of type BCn are essentially used in the study of the q-difference equations.
Solar energy export prospects of the Kingdom of Saudi Arabia
Authors: Zubair Muhammad , Awan Ahmed Bilal , Praveen R. P. , Abdulbaseer Muhammad
Published: July 2019

High energy utilization per capita and the country's gross domestic product (GDP) dependence on oil exports are the major problems of the Kingdom of Saudi Arabia (KSA). Abundant solar energy resources available in the country can help KSA to diversify its GDP. In this work, the photovoltaic (PV) energy outputs of KSA are compared with the potential PV energy customer such as European Countries, China, India, and Pakistan based on the levelized cost of energy (LCOE) and the net present cost (NPC). The PV energy is analyzed by a 4 GW grid connected PV system placed in the capital of each country. The grid sale price of PV energy is taken as half of the grid purchase energy price for each respective country. The high voltage direct current (HVDC) transmission of solar energy generated by the 4 GW PV system in KSA exported to potential customers is analyzed based on the NPC, LCOE, and payback period. Gwadar (Pakistan), (Antalya) Turkey, Karachi (Pakistan), and Ahmedabad (India) are economically feasible options with an LCOE of 5.2 ¢/kWh, 5.5 ¢/kWh, 6.2 ¢/kWh, and 7.5 ¢/kWh, respectively. The European countries are infeasible for PV energy export from KSA based on their load curves and NPC. The megacity of Karachi can be the first customer of KSA solar energy transmitted by HVDC.
Near-threshold photodissociation of cool OH+ to O + H+ and O+ + H
Authors: Hechtfischer U. , Levin J. , Lange M. , Knoll L. , Schwalm D. , Wester R. , Wolf A. , Zajfman D.
Published: July 2019

We have measured the spectrum of laser photodissociation of OH+ molecular ions to O + H+ and O+ + H fragments for photon energies of 38 100–40 900 cm−1. The OH+ ions were stored as a fast beam (5.50 MeV) in the storage ring TSR for several seconds to achieve rovibrational cooling into the lowest rotations N′′ = 0–11 of the vibrational ground state X3Σ−(v′′ = 0), close to room temperature (≈300 K). The many resonances in the spectra reveal the energies, widths, and O/O+ branching ratios of 44 predissociating quasibound levels (Feshbach resonances) that lie between the fine-structure states of the O fragment and belong to the last, near-threshold vibrational states v′ = 9 and 10 of the A3Π electronic state. For the A3Π0,1 substates, isolated levels with v′ = 11 are observed and attributed to double-well distortions of these curves due to nonadiabatic interactions. Another five isolated levels are assigned to the v′ = 0 and 1 states of the shallow 15Σ− electronic state, borrowing oscillator strength from nearby A3Π levels. Together, the near-threshold levels deliver a new value D0 = 40 253.8(1.1) cm−1 for the dissociation energy of OH+. Through a two-step photodissociation process, 72 levels from the lower bound states A3Π(v′ = 7–8) appear as well and are rotationally analyzed. The level energies are used to construct improved A3Π and 15Σ− Born-Oppenheimer potentials. The totality of the spectral data (energies, widths, intensities, and branching ratios) can provide tight constraints for the potentials and nonadiabatic interactions assumed in future coupled-channel calculations of OH+ photodissociation or of the related charge-exchange reaction O + H+ → O+ + H.
Role of magnetic field curvature in magnetohydrodynamic turbulence
Authors: Yang Yan , Wan Minping , Matthaeus William H. , Shi Yipeng , Parashar Tulasi N. , Lu Quanming , Chen Shiyi
Published: July 2019

Magnetic fields are transported and tangled by turbulence, even as they lose identity due to nonideal or resistive effects. In a balanced field, lines undergo stretch-twist-fold processes. The curvature field, a scalar that measures the tangling of the magnetic field lines, is studied in detail here, in the context of magnetohydrodynamic turbulence. A central finding is that the magnitudes of curvature and magnetic field are anticorrelated. A high curvature colocates with a low magnetic field, which gives rise to power-law tails of the probability density function of the curvature field. The curvature drift term that converts magnetic energy into flow and thermal energy largely depends on the curvature field behavior, a relationship that helps to explain particle acceleration due to the curvature drift. This adds as well to evidence that turbulent effects most likely play an essential role in particle energization since turbulence drives stronger tangled field configurations, and therefore curvature.
Time-dependent modeling on initiation of pre-ionized laser filament in atmospheric air under an external field far below conventional threshold
Authors: Yang Wei , Zhou Qianhong , Dong Zhiwei , Yan Eryan
Published: July 2019

In this paper, atmospheric laser filament initiation is simulated under an external field 5.7 kV/cm, which is far below the conventional breakdown threshold (25–30 kV/cm). The time-dependent model is based on a self-consistent solution to a coupled electron energy distribution function, vibrational kinetics, gas thermal balance, as well as detailed air chemistry. The model is validated with the experiment results on plasma density decay both with and without an external field. The slow decay of plasma density is ascribed to the decreased electron recombination and increased detachment rate under an external field. The initiation process is facilitated by the increase in the electron temperature, gas heating, and efficient vibrational excitation under the external field. We have varied the detachment rate between oxygen negative ions and nitrogen vibrational states to study its role on the initiation process, and found that larger detachment rates lead to shorter breakdown delay times. If the detachment rate is taken to be 3 × 10−11 cm3 s−1 as an upper limit, the breakdown threshold and delay time are consistent with the previous experiment study at least semiquantitatively. This work is beneficial for studying the initiation of a preformed laser filament under an external field as well as potential applications in lightning initiation and guiding below the conventional gas breakdown threshold.
Enhanced tunability in ferroelectric composites through local field enhancement and the effect of disorder
Authors: Vial Benjamin , Hao Yang
Published: July 2019

We investigate numerically the homogenized permittivities of composites made of low-index dielectric inclusions in a ferroelectric matrix under a static electric field. A refined model is used to take into account the coupling between the electrostatic problem and the electric field dependent permittivity of the ferroelectric material, leading to a local field enhancement and permittivity change in the ferroelectric. Periodic and pseudorandom structures in two dimensions are investigated, and we compute the effective permittivity, losses, electrically induced anisotropy, and tunability of these metamaterials. We show that the tunability of such composites might be substantially enhanced in the periodic case, whereas introducing disorder in the microstructure weakens the effect of the enhanced local permittivity change. Our results may be useful to guide the synthesis of novel composite ceramics with improved characteristics for controllable microwave devices.
Engineering tunnel junctions on ballistic semiconductor nanowires
Authors: Damasco J. , Gill S. T. , Gazibegovic S. , Badawy G. , Bakkers E. P. A. M. , Mason N.
Published: July 2019

Typical measurements of nanowire devices rely on end-to-end measurements to reveal mesoscopic phenomena such as quantized conductance or Coulomb blockades. However, creating nanoscale tunnel junctions allows one to directly measure other properties such as the density of states or electronic energy distribution functions. In this paper, we demonstrate how to realize uniform tunnel junctions on InSb nanowires, where the low invasiveness preserves ballistic transport in the nanowires. The utility of the tunnel junctions is demonstrated via measurements using a superconducting tunneling probe, which reveal nonequilibrium properties in the open quantum dot regime of an InSb nanowire. The method for high-quality tunnel junction fabrication on InSb nanowires is applicable to other III–V nanowires and enables characterization of nanowire local density of states.
Toward a wavefunction-based treatment of strong electron correlation in extended systems by means of incremental methods
Authors: Stoll Hermann
Published: July 2019

Incremental expansions have been used in the past to make electron correlation energies of large molecules and solids accessible to a treatment with wavefunction-based quantum-chemical methods. For this purpose, the Hartree-Fock space of occupied orbitals is partitioned into groups of localized orbitals; these groups are then correlated separately, one at a time, and their correlation energies are added up to a first estimate of the total correlation energy; subsequently, this estimate is systematically improved by correlating pairs, triples, etc., of the localized groups simultaneously. This works well when dynamic correlation effects are predominant and correlation effects rapidly decrease with the distance of the localization centers. For strong static correlation, Hartree-Fock is no longer a good starting point, localization is less well effective, and the convergence of the incremental scheme deteriorates. Here, two ways of improvement are considered for the latter case: optimization of the localized orbitals at a higher level than Hartree-Fock and use of incremental expansions from more than one reference determinant. These improvements are illustrated for H10 rings and H12 sheets up to dissociation and for the transition between the intra-atomic and interatomic bonding regimes in Be6 rings.
Hox genes limit germ cell formation in the short germ insect
Gryllus bimaculatus
Authors: Barnett Austen A. , Nakamura Taro , Extavour Cassandra G.
Published: July 2019

Significance

Hox genes are necessary for the proper placement of organs along animal body axes. In insects, Hox genes are used in a “code” of overlapping expression domains to specify body segments. We previously showed that, in the cricket
Gryllus bimaculatus
, germ cells are specified exclusively in the second through the fourth abdominal segments. Given the role of Hox genes in establishing segmental identity in insects, we tested the hypothesis that Hox genes control the segment-specific development of germ cells in crickets. We found that a subset of Hox genes limit germ cell development in the PGC-bearing segments. These data suggest a role for Hox genes in regulating germ cell placement.
Mechanical and kinetic factors drive sorting of F-actin cross-linkers on bundles
Authors: Freedman Simon L. , Suarez Cristian , Winkelman Jonathan D. , Kovar David R. , Voth Gregory A. , Dinner Aaron R. , Hocky Glen M.
Published: July 2019

In cells, actin-binding proteins (ABPs) sort to different regions to establish F-actin networks with diverse functions, including filopodia used for cell migration and contractile rings required for cell division. Recent experimental work uncovered a competition-based mechanism that may facilitate spatial localization of ABPs: binding of a short cross-linker protein to 2 actin filaments promotes the binding of other short cross-linkers and inhibits the binding of longer cross-linkers (and vice versa). We hypothesize this sorting arises because F-actin is semiflexible and cannot bend over short distances. We develop a mathematical theory and lattice models encompassing the most important physical parameters for this process and use coarse-grained simulations with explicit cross-linkers to characterize and test our predictions. Our theory and data predict an explicit dependence of cross-linker separation on bundle polymerization rate. We perform experiments that confirm this dependence, but with an unexpected cross-over in dominance of one cross-linker at high growth rates to the other at slow growth rates, and we investigate the origin of this cross-over with further simulations. The nonequilibrium mechanism that we describe can allow cells to organize molecular material to drive biological processes, and our results can guide the choice and design of cross-linkers for engineered protein-based materials.
SLAMF9 regulates pDC homeostasis and function in health and disease
Authors: Sever Lital , Radomir Lihi , Stirm Kristin , Wiener Anna , Schottlender Nofar , Lewinsky Hadas , Barak Avital F. , Friedlander Gilgi , Ben-Dor Shifra , Becker-Herman Shirly , Shachar Idit
Published: July 2019

SLAMF9 belongs to the conserved lymphocytic activation molecule family (SLAMF). Unlike other SLAMs, which have been extensively studied, the role of SLAMF9 in the immune system remained mostly unexplored. By generating CRISPR/Cas9 SLAMF9 knockout mice, we analyzed the role of this receptor in plasmacytoid dendritic cells (pDCs), which preferentially express the SLAMF9 transcript and protein. These cells display a unique capacity to produce type I IFN and bridge between innate and adaptive immune response. Analysis of pDCs in SLAMF9
−/−
mice revealed an increase of immature pDCs in the bone marrow and enhanced accumulation of pDCs in the lymph nodes. In the periphery, SLAMF9 deficiency resulted in lower levels of the transcription factor SpiB, elevation of pDC survival, and attenuated IFN-α and TNF-α production. To define the role of SLAMF9 during inflammation, pDCs lacking SLAMF9 were followed during induced experimental autoimmune encephalomyelitis. SLAMF9
−/−
mice demonstrated attenuated disease and delayed onset, accompanied by a prominent increase of immature pDCs in the lymph node, with a reduced costimulatory potential and enhanced infiltration of pDCs into the central nervous system. These results suggest the crucial role of SLAMF9 in pDC differentiation, homeostasis, and function in the steady state and during experimental autoimmune encephalomyelitis.
Blastocyst activation engenders transcriptome reprogram affecting X-chromosome reactivation and inflammatory trigger of implantation
Authors: He Bo , Zhang Hangxiao , Wang Jianqi , Liu Mengying , Sun Yang , Guo Chuanhui , Lu Jinhua , Wang Haibin , Kong Shuangbo
Published: July 2019

Implantation of the blastocyst into the uterus is the gateway for further embryonic development in mammals. Programming of blastocyst to an implantation-competent state known as blastocyst activation is the determining factor for implantation into the receptive uterus. However, it remains largely unclear how the blastocyst is globally programmed for implantation. Employing a delayed implantation mouse model, we show here that the blastocyst undergoes extensive programming essential for implantation. By analyzing the transcriptional profile of blastocysts with different implantation competency, we reveal the dynamic change in the biosynthesis, metabolism, and proliferation during blastocyst reactivation from diapause. We also demonstrate that reactivation of the X chromosome, one of the most important events during periimplantation of female embryonic development, is not completed even in blastocysts under conditions of dormancy, despite long term suspension in the uterus. Moreover, the mural trophectoderm (TE), but not the polar TE, differentiates to be more invasive through the weakened cell-cell tight junctions and extracellular matrices (ECMs). By analyzing the differentially expressed profile of secretory proteins, we further demonstrate that the blastocyst functions as a proinflammatory body to secrete proinflammatory signals, such as TNFα and S100A9, thereby triggering embryo-uterine attachment reaction during implantation. Collectively, our data systematically and comprehensively disclose the programming of blastocyst reactivation from diapause for implantation and uncover previously undefined roles of blastocyst during implantation.
A deep intronic splice mutation of
STAT3
underlies hyper IgE syndrome by negative dominance
Authors: Khourieh Joëlle , Rao Geetha , Habib Tanwir , Avery Danielle T. , Lefèvre-Utile Alain , Chandesris Marie-Olivia , Belkadi Aziz , Chrabieh Maya , Alwaseem Hanan , Grandin Virginie , Sarrot-Reynauld Françoise , Sénéchal Agathe , Lortholary Olivier , Kong Xiao-Fei , Boisson-Dupuis Stéphanie , Picard Capucine , Puel Anne , Béziat Vivien , Zhang Qian , Abel Laurent , Molina Henrik , Marr Nico , Tangye Stuart G. , Casanova Jean-Laurent , Boisson Bertrand
Published: July 2019

Significance

Heterozygous in-frame mutations in human
STAT3
coding regions underlie the only known autosomal dominant form of hyper IgE syndrome (AD HIES). About 5% of familial cases remain unexplained. We report a deep intronic heterozygous
STAT3
mutation, c.1282-89C>T, in 7 relatives with AD HIES. This mutation creates a new exon, encoding a new mRNA (D427ins17) and a mutant loss-of-function, dominant-negative STAT3 protein. This mutant protein was not detected in heterozygous cells from the patient. We show that the D427ins17 mutant allele is dominant-negative despite the production of significantly smaller amounts of mutant than of wild-type protein in heterozygous cells. These findings highlight the importance of searching for deep intronic mutations in
STAT3
before considering alternative genetic etiologies of HIES.
Collective sinking promotes selective cell pairing in planktonic pennate diatoms
Authors: Font-Muñoz Joan S. , Jeanneret Raphaël , Arrieta Jorge , Anglès Sílvia , Jordi Antoni , Tuval Idan , Basterretxea Gotzon
Published: July 2019

Significance

Planktonic pennate diatoms are a ubiquitous group of microalgae playing a major role as primary producers in aquatic ecosystems. Some species are also known to produce domoic acid, a neurotoxin that causes shellfish poisoning. Their reproduction is mostly accomplished through rapid clonal cell division, but eventual sexual exchange is required for population survival. How do nonswimming organisms find their partners in the water column? We demonstrate that planktonic pennate cells need to sink from surface turbulent waters to more stable environments where encounter rates, and thus pairing for sexual reproduction, are facilitated by viscous torques and collective interactions. This mechanism is key in our understanding of pennate diatom population dynamics and could help to improve prediction of some toxicity episodes.
Detection and activation of HIV broadly neutralizing antibody precursor B cells using anti-idiotypes
Authors: Bancroft Tara , DeBuysscher Blair L. , Weidle Connor , Schwartz Allison , Wall Abigail , Gray Matthew D. , Feng Junli , Steach Holly R. , Fitzpatrick Kristin S. , Gewe Mesfin M. , Skog Patrick D. , Doyle-Cooper Colleen , Ota Takayuki , Strong Roland K. , Nemazee David , Pancera Marie , Stamatatos Leonidas , McGuire Andrew T. , Taylor Justin J.
Published: July 2019

Many tested vaccines fail to provide protection against disease despite the induction of antibodies that bind the pathogen of interest. In light of this, there is much interest in rationally designed subunit vaccines that direct the antibody response to protective epitopes. Here, we produced a panel of anti-idiotype antibodies able to specifically recognize the inferred germline version of the human immunodeficiency virus 1 (HIV-1) broadly neutralizing antibody b12 (iglb12). We determined the crystal structure of two anti-idiotypes in complex with iglb12 and used these anti-idiotypes to identify rare naive human B cells expressing B cell receptors with similarity to iglb12. Immunization with a multimerized version of this anti-idiotype induced the proliferation of transgenic murine B cells expressing the iglb12 heavy chain in vivo, despite the presence of deletion and anergy within this population. Together, our data indicate that anti-idiotypes are a valuable tool for the study and induction of potentially protective antibodies.
Roadmap on photonic, electronic and atomic collision physics: III. Heavy particles: with zero to relativistic speeds
Authors: Aumayr Friedrich , Ueda Kiyoshi , Sokell Emma , Schippers Stefan , Sadeghpour Hossein , Merkt Frédéric , Gallagher Thomas F , Dunning F Barry , Scheier Paul , Echt Olof , Kirchner Tom , Fritzsche Stephan , Surzhykov Andrey , Ma Xinwen , Rivarola Roberto , Fojon Omar , Tribedi Lokesh , Lamour Emily , Crespo López-Urrutia José R , Litvinov Yuri A , Shabaev Vladimir , Cederquist Henrik , Zettergren Henning , Schleberger Marika , Wilhelm Richard A , Azuma Toshiyuki , Boduch Philippe , Schmidt Henning T , Stöhlker Thomas
Published: July 2019

We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. Roadmap III focusses on heavy particles: with zero to relativistic speeds. Modern theoretical and experimental approaches provide detailed insight into the wide range of many-body interactions involving projectiles and targets of varying complexity ranging from simple atoms, through molecules and clusters, complex biomolecules and nanoparticles to surfaces and crystals. These developments have been driven by technological progress and future developments will expand the horizon of the systems that can be studied. This Roadmap aims at looking back along the road, explaining the evolution of the field, and looking forward, collecting nineteen contributions from leading scientists in the field.
Tuning spinterface properties in iron/fullerene thin films
Authors: Mallik Srijani , Mohd Amir Syed , Koutsioubas Alexandros , Mattauch Stefan , Satpati Biswarup , Brückel Thomas , Bedanta Subhankar
Published: July 2019

In ferromagnetic (FM) metal/organic semiconductor (OSC) heterostructures charge transfer can occur which leads to induction of magnetism in the non-magnetic OSC. This phenomenon has been described by the change in the density of states in the OSC which leads to a finite magnetic moment at the OSC interface and it is called the ‘spinterface’. One of the main motivations in this field of organic spintronics is how to control the magnetic moment in the spinterface. In this regard, there are several open questions such as (i) which combination of FM and OSC can lead to more moment at the spinterface? (ii) Is the thickness of OSC also important? (iii) How does the spinterface moment vary with the FM thickness? (iv) Does the crystalline quality of the FM matter? (v) What is the effect of spinterface on magnetization reversal, domain structure and anisotropy? In this context, we have tried to answer the last four issues in this paper by studying Fe/C60 bilayers of variable Fe thickness deposited on Si substrates. We find that both the induced moment and thickness of the spinterface vary proportionally with the Fe thickness. Such behavior is explained in terms of the growth quality of the Fe layer on the native oxide of the Si (100) substrate. The magnetization reversal, domain structure and anisotropy of these bilayer samples were studied and compared with their respective reference samples without the C60 layer. It is observed that the formation of spinterface leads to a reduction in uniaxial anisotropy in Fe/C60 on Si (100) in comparison to their reference samples.
High-precision determination of silicon nanocrystals: optical spectroscopy versus electron microscopy
Authors: Köthemann Ronja , Weber Nils , Lindner Jörg K N , Meier Cedrik
Published: July 2019

We evaluate different approaches to determine the diameter of silicon nanoparticles in the regime of ultra-small particle sizes (

d
<
5

nm

). The nanocrystals are fabricated using a plasma-enhanced chemical vapor deposition (PECVD) process and are embedded in a matrix of SiO2. For characterization, different experimental techniques can be used, ranging from optical measurements such as photoluminescence or nonlinear optical response over transmission electron microscopy. An extensive analysis leads to a high-precision size determination and a good agreement between most of the techniques. Apart from the particle size, additional information can be derived depending on the method of choice, such as exciton fine structure splitting energy, width of the particle size distribution etc. While the nonlinear signal shows the expected enhancement for smaller nanoparticle sizes, it turns out to be inadequate for determination of particle sizes with a high accuracy.
Field-tuned spin excitation spectrum of kπ skyrmion
Authors: Song Chengkun , Ma Yunxu , Jin Chendong , Wang Jinshuai , Xia Haiyan , Wang Jianbo , Liu Qingfang
Published: July 2019

We study spin wave excitation modes of kπ skyrmion (k = 1, 2, 3) in a magnetic nanodot under an external magnetic field along the z direction using micromagnetic simulations based on the Landau–Lifshitz–Gilbert equation. We find that a transition of kπ skyrmion to other skyrmion-like structures appears under some critical external fields, the corresponding spin wave excitations are simulated for each state under magnetic field. For skyrmion, the frequencies of excitation modes increases and then decreases with the low frequency mode splitting at a critical magnetic field. In addition to the well-known two in-plane rotation modes and an out-of-plane breathing mode of skyrmion, more excitation modes are found with a higher k (k = 2, 3). The excitation modes vary as a function of magnetic field, and the excitation frequencies for different modes exhibit a rapid or slight change depending on the field-induced change of magnetization profile. Our study indicates the rich spin wave excitations for kπ skyrmion and opens up the possibility for theoretical or experimental investigation of magnonics application.
Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor ν = 2
Authors: Yang K F , Uddin M M , Nagase K , Mishima T D , Santos M B , Hirayama Y , Yang Z N , Liu H W
Published: July 2019

The nuclear spin-lattice relaxation time T
1 of the ν = 2 quantum Hall ferromagnet (QHF) formed in a gate-controlled InSb two-dimensional electron gas has been characterized using a pump-probe technique. In contrast to a long T
1 of quantum Hall states around ν = 1 that possesses a Korringa-type temperature dependence, the temperature-independent short T
1 of the ν = 2 QHF suggests the presence of low energy collective spin excitations in a domain wall. Furthermore, T
1 of this ferromagnetic state is also found to be filling- and current-independent. The interpretation of these results as compared to the T
1 properties of other QHFs is discussed in terms of the domain wall skyrmion, which will lead to a better understanding of the QHF.
Normal epithelial and triple-negative breast cancer cells show the same invasion potential in rigid spatial confinement
Authors: Ficorella Carlotta , Martínez Vázquez Rebeca , Heine Paul , Lepera Eugenia , Cao Jing , Warmt Enrico , Osellame Roberto , Käs Josef A
Published: July 2019

The extra-cellular microenvironment has a fundamental role in tumor growth and progression, strongly affecting the migration strategies adopted by single cancer cells during metastatic invasion. In this study, we use a novel microfluidic device to investigate the ability of mesenchymal and epithelial breast tumor cells to fluidize and migrate through narrowing microstructures upon chemoattractant stimulation. We compare the migration behavior of two mesenchymal breast cancer cell lines and one epithelial cell line, and find that the epithelial cells are able to migrate through the narrowest microconstrictions as the more invasive mesenchymal cells. In addition, we demonstrate that migration of epithelial cells through a highly compressive environment can occur in absence of a chemoattractive stimulus, thus evidencing that they are just as prone to react to mechanical cues as invasive cells.
A retrospective evaluation of automated optimization of deep brain stimulation parameters
Authors: Vorwerk Johannes , Brock Andrea A , Anderson Daria N , Rolston John D , Butson Christopher R
Published: July 2019

Objective. We performed a retrospective analysis of an optimization algorithm for the computation of patient-specific multipolar stimulation configurations employing multiple independent current/voltage sources. We evaluated whether the obtained stimulation configurations align with clinical data and whether the optimized stimulation configurations have the potential to lead to an equal or better stimulation of the target region as manual programming, while reducing the time required for programming sessions.Approach. For three patients (five electrodes) diagnosed with essential tremor, we derived optimized multipolar stimulation configurations using an approach that is suitable for the application in clinical practice. To evaluate the automatically derived stimulation settings, we compared them to the results of the monopolar review.Main results. We observe a good agreement between the findings of the monopolar review and the optimized stimulation configurations, with the algorithm assigning the maximal voltage in the optimized multipolar pattern to the contact that was found to lead to the best therapeutic effect in the clinical monopolar review in all cases. Additionally, our simulation results predict that the optimized stimulation settings lead to the activation of an equal or larger volume fraction of the target compared to the manually determined settings in all cases.Significance. Our results demonstrate the feasibility of an automatic determination of optimal DBS configurations and motivate a further evaluation of the applied optimization algorithm.
On the dynamics of a smart tensegrity structure using shape memory alloy
Authors: Martins Daniel , Paupitz Gonçalves Paulo José
Published: July 2019

A tensegrity system is composed by two types of elements, tensile and compressive parts, which promotes the structural stability of the system, in this case the tensile parts are cables (steel cables), and the compressive parts are bars made of steel. An attractive characteristic of a tensegrity structure is the capability to be deployable, for this reason, is interesting for space applications due to the small volume that occupy in a possible transport to a station outside the earth. In general, these structures can be large with many repetitive cells. In this work, a tensegrity boom structure consisting of ten periodic cells made of bars and cables is studied. The numerical model, obtained by finite element method, is validated experimentally considering the case of one structural cell. In order to make the system adaptable to external excitation, one of the steel cables in the tensegrity is replaced by a SMA (shape memory alloy) cable (nitinol) allowing the dynamics characteristics of the system to be changed according to an electrical current applied SMA. Various configurations for placing the SMA cable are studied with the objective of reducing the vibration amplitudes for harmonic force excitation.
Nonlinear rocking dynamics of pre-tensioned single rigid blocks under harmonic base excitation
Authors: Ahmadi E , Kashani M M
Published: July 2019

The rocking mechanism has been widely recognized as a beneficial technique to reduce structural damage arising from lateral excitations particularly earthquake loading, and hence, segmental pre-tensioned bridge piers have been recently emerged due to their self-centring property accompanied by accelerated construction of such structures. Hence, this study formulates the rocking dynamics of tied pre-tensioned single rigid blocks as an initial study for better understanding of dynamics of segmental pre-tensioned bridge piers. The nonlinear equation of rocking motion is then numerically solved under different range of base harmonic excitations. To achieve this, the rocking initiation condition is considered to determine initial conditions of rocking motion, an implicit solution is adopted to solve the equation of rocking motion and determine rocking response. Finally, a study is performed on a specific composite tied block to investigate effects of geometry and initial pre-tensioning force of the cable on the dynamic behaviour of the block. This study can find use in better understanding of segmental pre-tensioned columns.
Numerical computation of the spatial decaying wave characteristics for the design of locally resonant acoustic metamaterials
Authors: Miksch M , Perez Ramirez J D , Müller G
Published: July 2019

In structural dynamics, periodic resonant inclusions are widely used to improve the vibro-acoustic properties of lightweight structures. Depending on the design of these inclusions, the wave propagation in the structure is modified for specific frequency ranges and stop bands, where in theory no free wave propagation is possible, can be generated. The Wave Finite Element Method (WFEM) investigates the wave propagation in periodic structures based on a Finite Element (FE) model of a single unit cell. Using the direct approach of the WFEM, it is possible to depict the wave characteristics in the frequency range of the resonant frequency of the inclusions. Consequently, a spatial decay for the different wave types can be determined in the frequency range of the potential stop band. The frequency dependent decay characteristics can be used to evaluate the performance of the resonant inclusions and find optimal parameters for the desired application of the metamaterial. The procedure is applied to design beam-like resonators and find an optimal resonator spacing for a beam-like acoustic metamaterial. For a fixed percentage of added mass, the spacing of the resonators can be adjusted to optimize the maximum spatial decay or the stop band size.
Off-road motorcycle tyre force estimation
Authors: Vásquez F , Rustighi E , Lot R
Published: July 2019

To improve the performance of off-road motorcycles, tyre contact forces need to be estimated. Differently to on-road motorcycle contact force estimators where the rider can be considered attached to the chassis, an off-road motorcycles estimator needs to model the rider dynamics, since driving in standing position provides significant isolation from motorcycle motion. In this article, we use a novel simple rider model to approximate the interaction with the motorcycle when no sensing on him is possible. In particular, the novelty is to keep the pitch angle of the rider constant by means of an active torque on the hip. A tyre force estimator is built using this rider model coupled to a five degree-of-freedom motorcycle, which is verified with a virtual experiment performed on Working Model 2D, showing promising results.
Seismic Transient Simulation of an Operating Wind Turbine Considering the Soil-Structure Interaction
Authors: Schauer Marco , Taddei Francesca , Ríos Rodriguez Gustavo Adolfo
Published: July 2019

In this contribution we present a strategy to investigate the vibrations of onshore wind turbines subjected to simultaneous aerodynamic loads and seismic loads. The latter result from the propagation of seismic waves through the underlying soil and are governed by the Lamé’s equations.

The structure and its foundation as well as parts of the soil are modeled by Finite Element Method (FEM). The infinite half-space is discretized by Scaled Boundary Finite Element Method (SBFEM). Both methods are coupled at the common interface. The seismic excitation is expressed as a 3D seismic wave field and transformed into boundary tractions, which are then applied at the interface between the near and far fields. The aerodynamic actions are generated with an additional aerodynamic tool and are applied at the tower head.

The proposed method can be used also to investigate the 3D nonlinear response of the near field, where nonlinear material properties can be assigned to any element of FEM part.
Visco-elastic coupling between a linear two-dof system and a rocking rigid block to improve the dynamic response
Authors: Di Egidio A. , Contento A. , Fabrizio C. , de Leo A.M.
Published: July 2019

A two-degree of freedom linear system is used as a model for a multi-degree of freedom frame structure. Such a structure is coupled with a rocking rigid block to improve its dynamic response. The lowest part of the structure is connected to the block through a linear visco-elastic device. The nonlinear equations of motion of the couple system frame structure-block are obtained by a Lagrangian approach. Such equations are numerically integrated to analyze the behaviour of the coupled system. The coupling is considered effective if it reduces the displacements of the structure. Simulations are performed using a harmonic excitation as forcing term. An extensive parametric analysis is performed, and the results are summarized through behaviour maps. Such maps provide the ratio between the maximum displacements of the structure with and without the coupling with the rigid block for several combinations of system’s parameters. When the ratio of the displacements is less than unity, the coupling is effective. Results show that the presence of the rocking rigid block improves the dynamics of the structure in large ranges of the parameters that characterize the coupled system.
Nonparametric probabilistic approach for uncertainty quantification of geometrically nonlinear mistuned bladed-disks.
Authors: Capiez-Lernout Evangéline , Soize Christian
Published: July 2019

The present research concerns the dynamical analysis of mistuned rotating bladed-disks for which nonlinear geometrical effects exist. The present methodology requires the construction of an adapted reduced-order basis from which a nonlinear reduced-order model is constructed. The mistuning phenomenon is taken into account by considering a nonparametric probabilistic approach based on the information theory. In the present context the uncertainty is introduced by replacing the reduced-order basis with a stochastic reduced-order basis (SROB). This latter one is obtained by using a new nonparametric probabilistic approach of model-form uncertainties so that each realization of the SROB respects some mathematical properties linked to the available information under constraints concerning the specified boundary conditions and the usual orthogonality properties. With such strategy, the computational effort is focused on the stochastic nonlinear reduced internal forces and the related tangential operator which are explicitly constructed using the SROB combined with the finite element method. The numerical application is a rotating mistuned bladed-disk subjected to a load for which geometrical nonlinearities effects occur. The uncertainty propagation in this nonlinear dynamical system is then analyzed.