bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Coulomb collision between surface produced H− ions and H+ ions on H− extraction mechanism and beam optics in a Cs-seeded H− ion source by 3D particle in cell model
Authors: Nishioka S. , Abe S. , Miyamoto K. , Fukano A. , Hatayama A.
Published: February 2018

Recently, in Cs-seeded H− ion sources for fusion applications, the experiments have shown that the surface produced H− ions are mainly extracted from the bulk plasma region, that is, 1–2 cm inside from the beam aperture. The purpose of this paper is to clarify the extraction mechanism of the surface produced H− ions from the bulk plasma region in Cs-seeded H− ion sources for fusion applications by our 3-Dimensional Particle in Cell model for the vicinity of the beam aperture. In the present model, Coulomb collisions between surface produced H− ions and H+ ions (CC H−-H+) are taken into account by the Binary Collision Model. By our model, the trajectories of extracted surface produced H− ions and beam profiles have been investigated for the case with and without CC H−-H+. From the results of trajectories for extracted surface produced H− ions, it has been shown that the surface produced H− ions extracted from the bulk plasma region are drastically increased due to CC H−-H+. Thus, our results have shown that the surface produced H− ions are extracted from the bulk plasma region due to Coulomb collision with H+ ions. Moreover, our results of the beam profiles have shown that CC H−-H+ causes the increase in the beam convergence component. From these results, Coulomb collisions between surface produced H− ions and H+ ions are shown to be very important for the modeling of the extraction mechanism and for the beam optics in Cs-seeded H− ion sources for fusion applications.
Large moments in bcc FexCoyMnz ternary alloy thin films
Authors: Snow R. J. , Bhatkar H. , N'Diaye A. T. , Arenholz E. , Idzerda Y. U.
Published: February 2018

The elemental magnetic moments and the average atomic moment of 10–20 nm thick single crystal bcc (bct) FexCoyMnz films deposited on MgO(001) have been determined as a function of a broad range of compositions. Thin film epitaxy stabilized the bcc structure for 80% of the available ternary compositional space compared to only a 23% stability region for the bulk. The films that display ferromagnetism represent 60% of the available compositional possibilities compared to 25% for the bulk. A maximum average atomic moment of 3.25 ± 0.3 μB/atom was observed for a bcc Fe9Co62Mn29 film (well above the limit of the Slater-Pauling binary alloy curve of 2.45 μB/atom). The FexCoyMnz ternary alloys that exhibit high moments can only be synthesized as ultrathin films since the bcc structure is not stable in the bulk for those compositions.
Energetic analysis of drop’s maximum spreading on solid surface with low impact speed
Authors: Huang Hai-Meng , Chen Xiao-Peng
Published: February 2018

Drops impacting on a flat solid surface will spread until it reaches maximum contact with the substrate underneath. After that, it recoils. In the present work, the variations of energy components during the spreading are studied carefully, including kinetic, capillary, and dissipated energies. Our experimental and numerical results show that, when the impact speed is low, the fast slipping of the contact line (in inertia-capillary regime) and corresponding “interface relaxation” lead to extra dissipation. An auxiliary dissipation is therefore introduced into the traditional theoretical model. The energy components predicted by the improved model agree with the experimental and numerical results very well. As the impact speed increases (the Weber number, We=ρD0V02/γ, becomes larger than 40 in the present work), the dissipation induced by the initial velocity plays more important roles. The analyses also indicate that on the hydrophobic surfaces the auxiliary dissipation is lower than that on hydrophilic ones. In the later circumstances, the contact angle is larger and the spreading is weaker.
Validity of the isotropic thermal conductivity assumption in supercell lattice dynamics
Authors: Ma Ruiyuan , Lukes Jennifer R.
Published: February 2018

Superlattices and nano phononic crystals have attracted significant attention due to their low thermal conductivities and their potential application as thermoelectric materials. A widely used expression to calculate thermal conductivity, presented by Klemens and expressed in terms of the relaxation time by Callaway and Holland, originates from the Boltzmann transport equation. In its most general form, this expression involves a direct summation of the heat current contributions from individual phonons of all wavevectors and polarizations in the first Brillouin zone. In common practice, the expression is simplified by making an isotropic assumption that converts the summation over wavevector to an integral over wavevector magnitude. The isotropic expression has been applied to superlattices and phononic crystals, but its validity for different supercell sizes has not been studied. In this work, the isotropic and direct summation methods are used to calculate the thermal conductivities of bulk Si, and Si/Ge quantum dot superlattices. The results show that the differences between the two methods increase substantially with the supercell size. These differences arise because the vibrational modes neglected in the isotropic assumption provide an increasingly important contribution to the thermal conductivity for larger supercells. To avoid the significant errors that can result from the isotropic assumption, direct summation is recommended for thermal conductivity calculations in superstructures.
A sharp interface immersed boundary method for vortex-induced vibration in the presence of thermal buoyancy
Authors: Garg Hemanshul , Soti Atul K. , Bhardwaj Rajneesh
Published: February 2018

We report the development of an in-house fluid-structure interaction solver and its application to vortex-induced vibration (VIV) of an elastically mounted cylinder in the presence of thermal buoyancy. The flow solver utilizes a sharp interface immersed boundary method, and in the present work, we extend it to account for the thermal buoyancy using Boussinesq approximation and couple it with a spring-mass system of the VIV. The one-way coupling utilizes an explicit time integration scheme and is computationally efficient. We present benchmark code verifications of the solver for natural convection, mixed convection, and VIV. In addition, we verify a coupled VIV-thermal buoyancy problem at a Reynolds number, Re = 150. We numerically demonstrate the onset of the VIV in the presence of the thermal buoyancy for an insulated cylinder at low Re. The buoyancy is induced by two parallel plates, kept in the direction of flow and symmetrically placed around the cylinder. The plates are maintained at the hot and cold temperature to the same degree relative to the ambient. In the absence of the thermal buoyancy (i.e., the plates are at ambient temperature), the VIV does not occur for Re ≤ 20 due to stable shear layers. By contrast, the thermal buoyancy induces flow instability and the vortex shedding helps us to achieve the VIV at Re ≤ 20, lower than the critical value of Re (≈21.7), reported in the literature, for a self-sustained VIV in the absence of the thermal buoyancy. The present simulations show that the lowest Re to achieve VIV in the presence of the thermal buoyancy is around Re ≈ 3, at Richardson number, Ri = 1. We examine the effect of the reduced velocity (UR), mass ratio (m), Prandtl number (Pr), Richardson number (Ri) on the displacement of the cylinder, lift coefficient, oscillation frequency, the phase difference between displacement and lift force, and wake structures. We obtain a significantly larger vibration amplitude of the cylinder over a wide range of UR as compared to that in the absence of the thermal buoyancy.
Transverse and longitudinal magnetoelectric effect in multilayer Li0.058(Na0.535K0.48)0.942NbO3/Co0.6Zn0.4Fe1.7Mn0.3O4 bulk composites
Authors: Lin Ying , Qiu Yun , Zhang Jintao , Yang Haibo , Wang Tong , Yan Fei
Published: February 2018

We use the tape-casting technique to prepare multilayer magnetoelectric composites of Li0.058(Na0.535K0.48)0.942NbO3/Co0.6Zn0.4Fe1.7Mn0.3O4 (LKNN/CZFM). Scanning electron microscopy and energy-dispersive x-ray microanalysis indicate that the LKNN and CZFM phases coexist in these composites. The dielectric constant, piezoelectric constant, and ferroelectric properties of the multilayer composites deteriorate with increasing thickness tC of the CZFM layer. The maximum saturation polarization is 36.5 μC/cm2, and the maximum piezoelectric coefficient d33 is 205 pC/N. In addition, the maximum magnetoelectric coefficient is 322.3 mV cm−1 Oe−1.
Dirac cone in two dimensional bilayer graphene by intercalation with V, Nb, and Ta transition metals
Authors: Pakhira Srimanta , Lucht Kevin P. , Mendoza-Cortes Jose L.
Published: February 2018

Bilayer graphene (BLG) is a semiconductor whose band gap and properties can be tuned by various methods such as doping or applying gate voltage. Here, we show how to tune electronic properties of BLG by intercalation of transition metal (TM) atoms between two monolayer graphene (MLG) using a novel dispersion-corrected first-principle density functional theory (DFT) approach. We intercalated V, Nb, and Ta atoms between two MLG. We found that the symmetry, the spin, and the concentration of TM atoms in BLG-intercalated materials are the important parameters to control and to obtain a Dirac cone in their band structures. Our study reveals that the BLG intercalated with one vanadium (V) atom, BLG-1V, has a Dirac cone at the K-point. In all the cases, the present DFT calculations show that the 2pz sub-shells of C atoms in graphene and the 3dyz sub-shells of the TM atoms provide the electron density near the Fermi energy level (EF) which controls the material properties. Thus, we show that out-of-plane atoms can influence in-plane electronic densities in BLG and enumerate the conditions necessary to control the Dirac point. This study offers insight into the physical properties of 2D BLG intercalated materials and presents a new strategy for controlling the electronic properties of BLG through TM intercalation by varying the concentration and spin arrangement of the metals resulting in various conducting properties, which include: metal, semi-metal and semiconducting states.
A new surface-potential-based compact model for the MoS2 field effect transistors in active matrix display applications
Authors: Cao Jingchen , Peng Songang , Liu Wei , Wu Quantan , Li Ling , Geng Di , Yang Guanhua , Ji Zhouyu , Lu Nianduan , Liu Ming
Published: February 2018

We present a continuous surface-potential-based compact model for molybdenum disulfide (MoS2) field effect transistors based on the multiple trapping release theory and the variable-range hopping theory. We also built contact resistance and velocity saturation models based on the analytical surface potential. This model is verified with experimental data and is able to accurately predict the temperature dependent behavior of the MoS2 field effect transistor. Our compact model is coded in Verilog-A, which can be implemented in a computer-aided design environment. Finally, we carried out an active matrix display simulation, which suggested that the proposed model can be successfully applied to circuit design.
Initial stages of ion beam-induced phase transformations in Gd2O3 and Lu2O3
Authors: Chen Chien-Hung , Tracy Cameron L. , Wang Chenxu , Lang Maik , Ewing Rodney C.
Published: February 2018

The atomic-scale evolution of lanthanide sesquioxides Gd2O3 and Lu2O3 irradiated with 1 MeV Kr ions at room temperature and 120 K, up to fluences of 1 × 1016 ions/cm2 (∼20 dpa), has been characterized by in situ transmission electron microscopy. At room temperature, both oxides exhibited high radiation tolerance. Irradiation did not cause any observable structural change in either material, likely due to the mobility of irradiation-induced point defects, causing efficient defect annihilation. For Gd2O3, having the larger cation ionic radius of the two materials, an irradiation-induced stacking fault structure appeared at low fluences in the low temperature irradiation. As compared with the cubic-to-monoclinic phase transformations known to result from higher energy (∼GeV) ion irradiation, Kr ions of lower energies (∼MeV) yield much lower rates of damage accumulation and thus less extensive structural modification. At a fluence of 2.5 × 1015 ions/cm2, only the initial stages of the cubic-to-monoclinic (C to B) phase transformation process, consisting of the formation and aggregation of defects, have been observed.
From single helical relaxed states to helical equilibria
Authors: Paccagnella Roberto
Published: February 2018

This paper analyzes the relationship between the Single Helical relaxed states studied by R. Paccagnella [Phys. Plasmas 23, 092512 (2016)] and the so-called “helical ohmic equilibria,” i.e., plasma states that are solutions of the helical Grad Shafranov equation and that satisfy the constraint imposed by the Ohm law. The existence of marginally stable helical equilibria is clearly demonstrated, while the ohmic constraint is not exactly satisfied within the proposed first order perturbation theory. The model predictions are however satisfactorily compared with experimental trends.
Combining ability and heterosis analysis for mineral elements by using cytoplasmic male-sterile systems in non-heading Chinese cabbage (Brassica rapa)
Authors: Xie Fei , Zha Jun , Tang Hongyu , Xu Yuying , Liu Xujia , Wan Zhengjie
Published: February 2018

Brassica vegetables are an important source of dietary nutrition. The nutritional quality of mineral elements is becoming one of the most important studied traits because of the year-round supply of vegetables in China. However, there are few reports about breeding and utilisation of mineral elements in non-heading Chinese cabbage (Brassica napus L.). Using two newly reported CMS (cytoplasmic male-sterile) lines of non-heading Chinese cabbage, we conducted incomplete diallel experiments to analyse heterosis, combining ability and cytoplasmic effects for mineral elements such as calcium (Ca), iron (Fe), magnesium (Mg) and zinc (Zn). Heterosis analysis of mineral elements indicated that the crossing combinations A1 (hau CMS) × C03, A2 (eru CMS) × C03 and A2 × C11 exhibited desirable positive effects of mid-parent heterosis and high-parent heterosis in terms of mineral element content that could be exploited for commercial purposes. Analysis of general combining ability (GCA) effects of the parental lines indicated that the tester C11 was superior for the improvement of the four mineral elements; CMS line A1 had greater GCA effects than CMS line A2 for Ca and Fe. The hybrid combinations A2 × C11, B × C05 and B × C12 showed positive specific combining ability (SCA) effects for the four mineral elements on overall performance. The analysis revealed that cytoplasmic effects of hau CMS and eru CMS were both positive for Ca and Fe, and that A1 had more obvious cytoplasmic effects than did A2. These results indicated that the two isonuclear, alloplasmic CMS lines of non-heading Chinese cabbage might be useful for improving the nutritional quality traits of cruciferous vegetables and for heterosis utilisation.
An exploration of the experiences of Australian Grey Nomads travelling with chronic conditions
Authors: Calma Kaara Ray B. , Halcomb Elizabeth , Stephens Moira
Published: February 2018

Internationally, the population is ageing and people are living well, longer. In Australia, extended travelling has gained popularity among older Grey Nomads due to time and opportunity post retirement. However, there is limited research available focusing on older Australians’ health while travelling. This paper reports the qualitative phase of a larger mixed-method project that explores the experience of Australian Grey Nomads travelling with chronic conditions. Eight Grey Nomads participated in telephone interviews. Data were analysed using inductive thematic analysis. Two themes emerged, namely: continuity of care while travelling and experts on the road. Participants described encountering a fragmented health system, with challenges regarding finding health services; a lack of shared medical records; and difficulties accessing regular medications. Despite these challenges, participants demonstrated health preparedness, an ability to accommodate health on the road, and were all travelling for their health. This study highlights key systems issues that challenge health care while travelling, and identifies opportunities for both usual practices and rural health services to enhance the care provided to this group.
Nuclear quantum effect with pure anharmonicity and the anomalous thermal expansion of silicon
Authors: Kim D. S. , Hellman O. , Herriman J. , Smith H. L. , Lin J. Y. Y. , Shulumba N. , Niedziela J. L. , Li C. W. , Abernathy D. L. , Fultz B.
Published: February 2018

Significance

Silicon has a peculiar negative thermal expansion at low temperature. This behavior has been understood with a “quasiharmonic” theory where low-energy phonons decrease in frequency with volume contraction. We report inelastic neutron scattering measurements of phonon dispersions over a wide range of temperatures. These measurements cast doubt upon quasiharmonic theory, which predicts the wrong sign for most phonon shifts with temperature. Fully anharmonic ab initio calculations correctly predict the phonon shifts and thermal expansion. Crystal structure, anharmonicity, and nuclear quantum effects all play important roles in the thermal expansion of silicon, and a simple mechanical explanation is inappropriate. The quantum effect of nuclear vibrations is also expected to be important for thermophysical properties of many materials.
Suppression of RGSz1 function optimizes the actions of opioid analgesics by mechanisms that involve the Wnt/β-catenin pathway
Authors: Gaspari Sevasti , Purushothaman Immanuel , Cogliani Valeria , Sakloth Farhana , Neve Rachael L. , Howland David , Ring Robert H. , Ross Elliott M. , Shen Li , Zachariou Venetia
Published: February 2018

Regulator of G protein signaling z1 (RGSz1), a member of the RGS family of proteins, is present in several networks expressing mu opioid receptors (MOPRs). By using genetic mouse models for global or brain region-targeted manipulations of RGSz1 expression, we demonstrated that the suppression of RGSz1 function increases the analgesic efficacy of MOPR agonists in male and female mice and delays the development of morphine tolerance while decreasing the sensitivity to rewarding and locomotor activating effects. Using biochemical assays and next-generation RNA sequencing, we identified a key role of RGSz1 in the periaqueductal gray (PAG) in morphine tolerance. Chronic morphine administration promotes RGSz1 activity in the PAG, which in turn modulates transcription mediated by the Wnt/β-catenin signaling pathway to promote analgesic tolerance to morphine. Conversely, the suppression of RGSz1 function stabilizes Axin2–Gαz complexes near the membrane and promotes β-catenin activation, thereby delaying the development of analgesic tolerance. These data show that the regulation of RGS complexes, particularly those involving RGSz1-Gαz, represents a promising target for optimizing the analgesic actions of opioids without increasing the risk of dependence or addiction.
Elucidating the structural basis for differing enzyme inhibitor potency by cryo-EM
Authors: Rawson Shaun , Bisson Claudine , Hurdiss Daniel L. , Fazal Asif , McPhillie Martin J. , Sedelnikova Svetlana E. , Baker Patrick J. , Rice David W. , Muench Stephen P.
Published: February 2018

Histidine biosynthesis is an essential process in plants and microorganisms, making it an attractive target for the development of herbicides and antibacterial agents. Imidazoleglycerol-phosphate dehydratase (IGPD), a key enzyme within this pathway, has been biochemically characterized in both
Saccharomyces cerevisiae
(
Sc_
IGPD) and
Arabidopsis thaliana
(
At_
IGPD). The plant enzyme, having been the focus of in-depth structural analysis as part of an inhibitor development program, has revealed details about the reaction mechanism of IGPD, whereas the yeast enzyme has proven intractable to crystallography studies. The structure–activity relationship of potent triazole-phosphonate inhibitors of IGPD has been determined in both homologs, revealing that the lead inhibitor (C348) is an order of magnitude more potent against
Sc_
IGPD than
At_
IGPD; however, the molecular basis of this difference has not been established. Here we have used single-particle electron microscopy (EM) to study structural differences between the
At
and
Sc_
IGPD homologs, which could influence the difference in inhibitor potency. The resulting EM maps at ∼3 Å are sufficient to de novo build the protein structure and identify the inhibitor binding site, which has been validated against the crystal structure of the
At_
IGPD/C348 complex. The structure of
Sc
_IGPD reveals that a 24-amino acid insertion forms an extended loop region on the enzyme surface that lies adjacent to the active site, forming interactions with the substrate/inhibitor binding loop that may influence inhibitor potency. Overall, this study provides insights into the IGPD family and demonstrates the power of using an EM approach to study inhibitor binding.
Bayesian selection of misspecified models is overconfident and may cause spurious posterior probabilities for phylogenetic trees
Authors: Yang Ziheng , Zhu Tianqi
Published: February 2018

Significance

The Bayesian method is widely used to estimate species phylogenies using molecular sequence data. While it has long been noted to produce spuriously high posterior probabilities for trees or clades, the precise reasons for this overconfidence are unknown. Here we characterize the behavior of Bayesian model selection when the compared models are misspecified and demonstrate that when the models are nearly equally wrong, the method exhibits unpleasant polarized behaviors, supporting one model with high confidence while rejecting others. This provides an explanation for the empirical observation of spuriously high posterior probabilities in molecular phylogenetics.
GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving
Drosophila
Authors: Gowda Swetha B. M. , Paranjpe Pushkar D. , Reddy O. Venkateswara , Thiagarajan Devasena , Palliyil Sudhir , Reichert Heinrich , VijayRaghavan K.
Published: February 2018

Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in
Drosophila
to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking
Drosophila
. Our findings indicate that targeted down-regulation of the GABA
A
receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving
Drosophila
.
Maximizing the information learned from finite data selects a simple model
Authors: Mattingly Henry H. , Transtrum Mark K. , Abbott Michael C. , Machta Benjamin B.
Published: February 2018

Significance

Most physical theories are effective theories, descriptions at the scale visible to our experiments which ignore microscopic details. Seeking general ways to motivate such theories, we find an information theory perspective: If we select the model which can learn as much information as possible from the data, then we are naturally led to a simpler model, by a path independent of concerns about overfitting. This is encoded as a Bayesian prior which is nonzero only on a subspace of the original parameter space. We differ from earlier prior selection work by not considering an infinite quantity of data. Having finite data is always a limit on the resolution of an experiment, and in our framework this selects how complicated a theory is appropriate.
Adaptive evolution of genomically recoded
Escherichia coli
Authors: Wannier Timothy M. , Kunjapur Aditya M. , Rice Daniel P. , McDonald Michael J. , Desai Michael M. , Church George M.
Published: February 2018

Significance

The construction of an organism with an altered genetic code negatively impacted its fitness. We evolved this organism for ∼1,100 generations in the laboratory to recover fitness and learn what changes would accumulate during evolutionary trajectories toward faster growth rates. We observed several selective mutations that helped alleviate insufficient translation termination or that corrected for unintended mutations that accumulated when we originally altered the genetic code. Further observed mutations were generally adaptive in a nonrecoded background. This work bolsters our understanding of the pliability of the genetic code and will help guide future efforts seeking to recode genomes. Finally, it results in a useful strain for nonstandard amino acid incorporation in numerous contexts relevant for research and industry.
16p11.2 transcription factor
MAZ
is a dosage-sensitive regulator of genitourinary development
Authors: Haller Meade , Au Jason , O’Neill Marisol , Lamb Dolores J.
Published: February 2018

Significance

Copy number gains and losses have long been studied as the potential causes of various congenital defects. Urogenital birth defects account for as many at 30% of structural anomalies, and the 16p11.2 genetic locus is among the most common copy variant regions. Herein is shown that variation in copy number of the transcription factor
MA
Z
, located within the 16p11.2 locus, contributes significantly to a wide range of the urogenital birth defects associated with this genomic syndrome, including structural abnormalities of the developing kidneys, ureters, and bladder. Understanding large chromosomal aberrations by studying the functions of individual developmental genes at each variant locus will pave the way for future targeted therapies in affected pregnancies.
Time-spliced X-ray diffraction imaging of magnetism dynamics in a NdNiO
3
thin film
Authors: Beyerlein Kenneth R.
Published: February 2018

Significance

Imaging the atomic-scale dynamics of thin films is important to develop the next generation of computer technology. Coherent diffraction imaging can provide this information for other dimensionalities, but is unreliable when applied to thin-film measurements. This paper describes an approach to solving this problem using many measurements on a system that is changing in time. As an example, a demagnetization front is imaged as it sweeps through an antiferromagnetic film at twice the speed of sound, leaving a paramagnetic state in its wake. This fast switching is initiated by a midinfrared pulse tuned to the substrate. The recovered magnetization evolution then shows the potential for control of optoelectronic switching devices by driving interface lattice dynamics.
Global changes of H3K27me3 domains and Polycomb group protein distribution in the absence of recruiters Spps or Pho
Authors: Brown J. Lesley , Sun Ming-an , Kassis Judith A.
Published: February 2018

Polycomb group (PcG) proteins maintain the silenced state of key developmental genes in animals, but how these proteins are recruited to specific regions of the genome is still poorly understood. InDrosophila, PcG proteins are recruited to Polycomb response elements (PREs) that include combinations of sites for sequence specific DNA binding “PcG recruiters,” including Pho, Cg, and Spps. To understand their roles in PcG recruitment, we compared Pho-, Cg-, and Spps-binding sites against H3K27me3 and key PcG proteins by ChIP-seq in wild-type and mutant third instar larvae. H3K27me3 in canonical Polycomb domains is decreased after the reduction of any recruiter. Reduction of Spps and Pho, but not Cg, causes the redistribution of H3K27me3 to heterochromatin. Regions with dramatically depleted H3K27me3 after Spps knockout are usually accompanied by decreased Pho binding, suggesting their cooperative binding. PcG recruiters, the PRC2 component E(z), and the PRC1 components Psc and Ph cobind thousands of active genes outside of H3K27me3 domains. This study demonstrates the importance of distinct PcG recruiters for the establishment of unique Polycomb domains. Different PcG recruiters can act both cooperatively and independently at specific PcG target genes, highlighting the complexity and diversity of PcG recruitment mechanisms.
Microstructural origin of resistance–strain hysteresis in carbon nanotube thin film conductors
Authors: Jin Lihua , Chortos Alex , Lian Feifei , Pop Eric , Linder Christian , Bao Zhenan , Cai Wei
Published: February 2018

A basic need in stretchable electronics for wearable and biomedical technologies is conductors that maintain adequate conductivity under large deformation. This challenge can be met by a network of one-dimensional (1D) conductors, such as carbon nanotubes (CNTs) or silver nanowires, as a thin film on top of a stretchable substrate. The electrical resistance of CNT thin films exhibits a hysteretic dependence on strain under cyclic loading, although the microstructural origin of this strain dependence remains unclear. Through numerical simulations, analytic models, and experiments, we show that the hysteretic resistance evolution is governed by a microstructural parameter

ξ

(the ratio of the mean projected CNT length over the film length) by showing that

ξ

is hysteretic with strain and that the resistance is proportional to

ξ

−
2

. The findings are generally applicable to any stretchable thin film conductors consisting of 1D conductors with much lower resistance than the contact resistance in the high-density regime.
Climate-change–driven accelerated sea-level rise detected in the altimeter era
Authors: Nerem R. S. , Beckley B. D. , Fasullo J. T. , Hamlington B. D. , Masters D. , Mitchum G. T.
Published: February 2018

Significance

Satellite altimetry has shown that global mean sea level has been rising at a rate of ∼3 ± 0.4 mm/y since 1993. Using the altimeter record coupled with careful consideration of interannual and decadal variability as well as potential instrument errors, we show that this rate is accelerating at 0.084 ± 0.025 mm/y
2
, which agrees well with climate model projections. If sea level continues to change at this rate and acceleration, sea-level rise by 2100 (∼65 cm) will be more than double the amount if the rate was constant at 3 mm/y.
Demographically diverse crowds are typically not much wiser than homogeneous crowds
Authors: de Oliveira Stephanie , Nisbett Richard E.
Published: February 2018

Averaging independent numerical judgments can be more accurate than the average individual judgment. This “wisdom of crowds” effect has been shown with large, diverse samples, but the layperson wishing to take advantage of this may only have access to the opinions of a small, more demographically homogeneous “convenience sample.” How wise are homogeneous crowds relative to diverse crowds? In simulations and survey studies, we demonstrate three necessary conditions under which small socially diverse crowds can outperform socially homogeneous crowds: Social identity must predict judgment, the effect of social identity on judgment must be at least moderate in size, and the average estimates of the social groups in question must “bracket” the truth being judged. Seven survey studies suggest that these conditions are rarely met in real judgment tasks. Comparisons between the performances of diverse and homogeneous crowds further confirm that social diversity can make crowds wiser but typically by a very small margin.
Transcriptome dynamics at
Arabidopsis
graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration
Authors: Melnyk Charles W. , Gabel Alexander , Hardcastle Thomas J. , Robinson Sarah , Miyashima Shunsuke , Grosse Ivo , Meyerowitz Elliot M.
Published: February 2018

Significance

Plant grafting is an ancient and agriculturally important technique. Despite its widespread use, little is known about how plants graft. Here, we perform a genome-wide transcriptome analysis of tissues above and below graft junctions. We observed a sequential activation of genes important for vascular development including cambium-, phloem-, and xylem-related genes. Massive changes in gene expression that rapidly differentiate the top of the graft from the bottom occur. These changes disappear as the graft heals and the vasculature reconnects. Many genes below the junction rapidly respond to the presence of attached tissues including genes involved in vascular differentiation and cell division. This intertissue communication process occurs independently of functional vascular connections and acts as a signal to activate vascular regeneration.
Compartmentalization of antagonistic Ca
2+
signals in developing cochlear hair cells
Authors: Moglie Marcelo J. , Fuchs Paul A. , Elgoyhen Ana Belén , Goutman Juan D.
Published: February 2018

Significance

Cochlear inner hair cells (IHCs) are responsible for transducing sound waves and relaying acoustic information to the brain through its afferent synapse. During development, IHCs exhibit sensory-independent activity, supported by voltage-gated Ca
2+
influx, which is critical for the normal maturation of the auditory system. This spontaneous activity is modulated by an inhibitory cholinergic input, mediated by nicotinic receptors with unusually high Ca
2+
permeability, leading to the activation of hyperpolarizing SK channels. Thus, Ca
2+
should play distinct excitatory and inhibitory roles in small, compact IHCs. This work presents evidence for specialized cellular mechanisms that maintain local compartmentalization of Ca
2+
signals and prevent synaptic cross-talk. Thus, the cholinergic input preserves its inhibitory signature to ensure normal development of the auditory system.
Polo-like kinase 4 inhibition produces polyploidy and apoptotic death of lung cancers
Authors: Kawakami Masanori , Mustachio Lisa Maria , Zheng Lin , Chen Yulong , Rodriguez-Canales Jaime , Mino Barbara , Kurie Jonathan M. , Roszik Jason , Villalobos Pamela Andrea , Thu Kelsie L. , Silvester Jennifer , Cescon David W. , Wistuba Ignacio I. , Mak Tak W. , Liu Xi , Dmitrovsky Ethan
Published: February 2018

Significance

Despite current treatments, lung cancers remain a major public health problem. Innovative ways are needed to treat or prevent these cancers. Centrosomes are critical for fidelity of mitosis. Abnormal centrosome numbers can cause aberrant mitosis and cell death. Polo-like kinase 4 (PLK4) regulates centriole duplication, and its deregulation alters centrosome number and mitosis. The potent PLK4 inhibitor CFI-400945 is reported here to exert marked antineoplastic effects against lung cancers. CDK2 inhibition also deregulates mitosis and was found to cooperate with PLK4 antagonism. CFI-400945 is now undergoing phase I clinical trial testing (NCT01954316). Taken together, targeting PLK4 for inhibition holds promise in lung cancer therapy either as a single agent or when combined with an agent that deregulates mitosis.
Three classes of recurrent DNA break clusters in brain progenitors identified by 3D proximity-based break joining assay
Authors: Wei Pei-Chi , Lee Cheng-Sheng , Du Zhou , Schwer Bjoern , Zhang Yuxiang , Kao Jennifer , Zurita Jeffrey , Alt Frederick W.
Published: February 2018

We recently discovered 27 recurrent DNA double-strand break (DSB) clusters (RDCs) in mouse neural stem/progenitor cells (NSPCs). Most RDCs occurred across long, late-replicating RDC genes and were found only after mild inhibition of DNA replication. RDC genes share intriguing characteristics, including encoding surface proteins that organize brain architecture and neuronal junctions, and are genetically implicated in neuropsychiatric disorders and/or cancers. RDC identification relies on high-throughput genome-wide translocation sequencing (HTGTS), which maps recurrent DSBs based on their translocation to “bait” DSBs in specific chromosomal locations. Cellular heterogeneity in 3D genome organization allowed unequivocal identification of RDCs on 14 different chromosomes using HTGTS baits on three mouse chromosomes. Additional candidate RDCs were also implicated, however, suggesting that some RDCs were missed. To more completely identify RDCs, we exploited our finding that joining of two DSBs occurs more frequently if they lie on the same
cis
chromosome. Thus, we used CRISPR/Cas9 to introduce specific DSBs into each mouse chromosome in NSPCs that were used as bait for HTGTS libraries. This analysis confirmed all 27 previously identified RDCs and identified many new ones. NSPC RDCs fall into three groups based on length, organization, transcription level, and replication timing of genes within them. While mostly less robust, the largest group of newly defined RDCs share many intriguing characteristics with the original 27. Our findings also revealed RDCs in NSPCs in the absence of induced replication stress, and support the idea that the latter treatment augments an already active endogenous process.
Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness
Authors: Zhai Zirui , Wang Yong , Jiang Hanqing
Published: February 2018

Significance

Origami has been employed to build deployable mechanical metamaterials through folding and unfolding along the crease lines. These deployable structures are flexible in their deployment direction so that they can be easily collapsed along the same path they are deployed. Here we create an origami-inspired mechanical metamaterial with on-demand deployability and selective collapsibility: autonomous deployability from the collapsed state and selective collapsibility along two different paths, with low stiffness for one path and substantially high stiffness for another path. The created mechanical metamaterial yields load-bearing capability in the deployed direction while still possessing great deployability and collapsibility. The principle in this work can be utilized to design and create versatile origami-inspired mechanical metamaterials that can find many applications.
To be or not to be your son’s father/mother
Authors: Salamh Sami Ben , Maalej Zouheir , Alghbban Mohammed
Published: February 2018

The current article offers a comparative account of the address system of two dialects of Arabic, Najdi and Tunisian Arabic. Capitalizing on the theory of Idealized Cognitive Model, the article defends the view that the two systems display Idealized models, which are central to the system, and non-Idealized models, which are peripheral to it. Najdi Arabic includes Idealized terms such as first names, teknonyms, and kinship terms while non-Idealized models include a battery of terms of address. Tunisian Arabic Idealized models hinge on Si/Lalla + first names, first names, and kinship terms while non-Idealized models make use of endeared first names, kinship terms, and diminished kinship terms. The two systems are shown to differ at the level of types of encounter (including formality, closeness, and deference), availability of address options, socialhorizontality-verticality, and use of metaphor and metonymy.
Varestraint weldability testing of additive manufactured alloy 718
Authors: Raza Tahira , Andersson Joel , Svensson Lars-Erik
Published: February 2018

The weldability in terms of susceptibility towards hot cracking of selective laser melted (SLM) Alloy 718 was investigated and wrought Alloy 718 was used as reference material. Varestraint testing was carried out by means of investigating the weldability in three conditions; (1) SLM as-built, (2) hot isostatic pressing at 1160°C at 105 MPa for 3 h and (3) wrought Alloy 718 in the mill-annealed condition. The material exhibited intergranular cracking in all three conditions; however, the SLM HIPed condition had an increased magnitude of crack susceptibility at all strain levels. The increased sensitivity of the HIPed material was due to the significantly larger grain size in comparison. The SLM as-built condition showed the same degree of cracking as the wrought material.
Farmers Markets and Food‐Borne Illness*
Authors: Bellemare Marc F. , Nguyen Ngoc (Jenny)
Published: February 2018

Using longitudinal administrative data on all U.S. states and the District of Columbia for the years 2004, 2006, and 2008–2013, we study the relationship between farmers markets and food‐borne illness. We find a positive relationship between the number of farmers markets per million individuals and the number per million of reported (i) total outbreaks and cases of food‐borne illness, (ii) outbreaks and cases of norovirus, and (iii) outbreaks of campylobacter in the average state‐year. Our estimates indicate that doubling the number of farmers markets in the average state‐year would be associated with 2.6 additional outbreaks of food‐borne illness, 0.8 additional outbreaks of norovirus, and 0.3 additional outbreaks of campylobacter per million, as well as with 34.5 additional total cases of food‐borne illness, 22.9 additional cases of norovirus, and 1.5 additional cases of campylobacter per million in the same state‐year. Our core results are robust to different specifications as well as to deleting outliers and leverage points.
What Works and Does Not Work in a Self-Management Intervention for People With Chronic Pain? Qualitative Systematic Review and Meta-Synthesis
Authors: Devan Hemakumar , Hale Leigh , Hempel Dagmar , Saipe Barbara , Perry Meredith A
Published: February 2018

Background

Self-management interventions fostering self-efficacy improve the well-being of people with chronic pain.

Purpose

The purpose of this study was to synthesize the enablers (what works) and barriers (what does not) of incorporating self-management strategies for people in everyday life after completion of a pain self-management intervention.

Data Sources

Major electronic databases (MEDLINE, AMED, PsycINFO, Cochrane Library, PubMed, CINAHL, Scopus, and Google Scholar) were searched from inception to July 2016.

Study Selection

Study selection included qualitative and mixed-method studies that explored the perceptions of individuals with chronic pain after completion of a self–management intervention.

Data Extraction

A thematic analysis approach was used to synthesize the review findings, and a Confidence in the Evidence from Reviews of Qualitative Research (CERQual) Approach was used to assess the level of confidence.

Data Synthesis

Thirty-three studies with 512 participants were included. Enablers to self-management included self-discovery—the ability to distinguish self (ie, body, thoughts, and feelings) from pain; feeling empowered by incorporating self-management strategies into practice; and supportive ambience via collaborative relationships with clinicians and support from family and friends. Barriers to self-management included difficulty with sustaining motivation for pain self-management; distress experienced from ongoing pain, anxiety, and depression; and unsupportive relationships with clinicians, family, and friends.

Limitations

This review only included interventions that involved at least 4 self–management skills; thus, informative studies may have been missed. The follow-up period varied from immediately after the intervention to 72 months following the intervention; therefore, it is uncertain which of the key enablers and barriers were most influential long term. Only articles published in the English language were included; studies conducted in low- and middle-income countries could not be located.

Conclusions

The sustained effort to self-manage chronic pain could be exhausting, and motivation could wane over time following intervention. Providing intermittent support in the form of booster sessions and peer support groups may be important. Person-centered care via shared decision making and guided problem solving is essential to facilitating ongoing self-management.
Clusters of health behaviours in Queensland adults are associated with different socio-demographic characteristics
Authors: Hobbs M , Duncan M J , Collins P , Mckenna J , Schoeppe S , Rebar A L , Alley S , Short C , Vandelanotte C
Published: February 2018

Background

The co-occurrence of unhealthy lifestyles, calls for interventions that target multiple health behaviours. This study investigates the clustering of health behaviours and examines demographic differences between each cluster.

Methods

In total, 934 adults from Queensland, Australia completed a cross-sectional survey assessing multiple health behaviours. A two-step hierarchical cluster analysis using multiple iterations identified the optimal number of clusters and the subset of distinguishing health behaviour variables. Univariate analyses of variance and chi-squared tests assessed difference in health behaviours by socio-demographic factors and clusters.

Results

Three clusters were identified: the ‘lower risk’ cluster (n = 436) reported the healthiest profile and met all public health guidelines. The ‘elevated risk’ cluster (n = 105) reported a range of unhealthy behaviours such as excessive alcohol consumption, sitting time, fast-food consumption, smoking, inactivity and a lack of fruit and vegetables. The ‘moderate risk behaviour’ cluster (n = 393) demonstrated some unhealthy behaviours with low physical activity levels and poor dietary outcomes. The ‘elevated risk’ cluster were significantly younger and more socio-economically disadvantaged than both the ‘lower and moderate risk’ clusters.

Discussion

Younger people who live in more deprived areas were largely within the ‘elevated risk’ cluster and represent an important population for MHBC interventions given their wide range of unhealthy behaviours.