bluuebunny/crossref_metadata_2025 huggingface dataset:
Uses of social media in government agencies: Content analyses of public relations strategies and message tactics comparison between South Korea and the United States of America in 2011 and 2014
Authors: Lee Moon J. , Cho Hajin
Published: November 2017

We investigated five different government organizations' uses of social media in two countries: South Korea and the United States. Two content analyses were conducted in two time periods: 2011 and 2014. We found that the majority of government organizations in both countries use social media within the public information model (for dissemination of information), followed by the two‐way asymmetrical model (for persuasion). As expected, the most prevalent public relations strategy is informative strategy, followed by persuasive strategy. The majority of government organizations use the information dissemination message strategy. Specific differences were found between 2011 and 2014 as well as between two countries.
Does Paid Family Leave Reduce Nursing Home Use? The California Experience
Authors: Arora Kanika , Wolf Douglas A.
Published: November 2017

The intent of Paid Family Leave (PFL) is to make it financially easier for individuals to take time off from paid work to care for children and seriously ill family members. Given the linkages between care provided by family members and the usage of paid services, we examine whether California's PFL program influenced nursing home utilization in California during the 1999 to 2008 period. This is the first empirical study to examine the effects of PFL on long‐term care patterns. Multivariate difference‐in‐difference estimates across alternative comparison groups provide consistent evidence that the implementation of PFL reduced the proportion of the elderly population in nursing homes by 0.5 to 0.7 percentage points. Our preferred estimate, employing an empirically‐matched group of control states, finds that PFL reduced nursing home usage by about 0.65 percentage points. For California, this represents an 11 percent relative decline in elderly nursing home utilization.
School counseling: Partnering with a school district to provide postsecondary opportunities for first generation, low income, and students of color
Authors: Pérusse Rachelle , DeRonck Nicole , Parzych Jennifer
Published: November 2017

A classroom activity led by district school counselors was conducted in a K‐12 school district to ensure educational equity for students in relation to postsecondary attendance. This took place in a school setting that has a large population of students of color, predominately Latino and African American students, as well as low‐income students. As part of their practicum field experience, university school counseling students were supervised by school counselors at their sites to help provide a readily available and modified curriculum to instruct students about their options related to postsecondary awareness, planning, and attendance, as well as demonstrate career pathways that engender high expectations and college and career readiness. Instruction took place in the classroom as well as in small group settings.
Blends of linear and peroxide‐modified branched polylactide for extrusion coating
Authors: Khajeheian M.B. , Kuusipalo J. , Rosling A.
Published: November 2017

The purpose of the present work was to improve melt rheological properties of linear poly(L‐lactide) (PLLA) by melt blending with peroxide‐modified branched PLLA for extrusion coating. Peroxide‐modified PLLA, ie, PLLA melt extruded with 0.3 wt% of tert‐Butyl‐peroxybenzoate (TBPB); 2,5‐dimethyl‐2,5‐(tert‐butylperoxy)‐hexane (Lupersol 101 [LOL1]); and benzoyl peroxide was added to linear PLLA in ratios of 5, 15, and 30 wt%. All blends showed increased zero shear viscosity, elastic feature (storage modulus, decreased tan delta), and shear sensitivity. The blends' properties were mostly dependent on the peroxide applied for the modification and, to some extent, on the amount of added peroxide‐modified PLLA. Rheological models suggest that all blend compositions are mainly immiscible. Thermal properties were unchanged; all materials remained amorphous, though the enthalpy of cold crystallization was slightly increased. Extrusion coating on paperboard was conducted with PLLA and peroxide‐modified PLLA blends (90:10). All blends were processable; however, only that made with 2,5‐dimethyl‐2,5‐(tert‐butylperoxy)‐hexane (LOL1) afforded a smooth high‐quality coating surface with improved line speed. Adhesion levels between fibre and plastic and heat seal performance were marginally reduced compared with pure PLLA (3051D). The water vapour transmission measurements with 2,5‐dimethyl‐2,5‐(tert‐butylperoxy)‐hexane (LOL1) showed acceptable water transmission levels, being only slightly higher than for neat PLLA coating.
Nonlinear formation control strategies for agents without relative measurements under heterogeneous networks
Authors: Sen Arijit , Sahoo Soumya Ranjan , Kothari Mangal
Published: November 2017

This paper proposes cooperative control protocols for a group of unmanned vehicles to make a stable formation around a maneuvering target. The control protocols are proposed on the basis of heterogeneous communication networks, which represents more challenging and generalized situations. Two different scenarios are considered. Separate control protocols are developed for each case. In both scenarios, agents do not have relative position, velocity, and acceleration measurements as feedback. In the first scenario, each agent uses its own position and velocity measurement in a consensus algorithm. In the second scenario, each agent needs only its own position information for the consensus algorithm. For both protocols, agents compute virtual estimates of a target's position and velocity and exchange these among the neighbors. Three different communication networks are used for exchanging two virtual estimates calculated by each agent and a time derivative of one virtual estimate. Each interagent communication network is represented by a fixed, undirected, and connected graph. Furthermore, it is considered that at least one agent receives the position, velocity, and acceleration information of the maneuvering target. It is not necessary that the agent receiving the target's position and the agent receiving the velocity and/or the acceleration information of the target be the same. However, the target does not receive any information about any agent. Stability of the formation is analyzed by using Barbalat's lemma. It is also shown that, despite the large difference in received information, the acceleration of the agents remains bounded for all time. The performance of the proposed formation control protocols is illustrated through numerical simulations.
Empirical likelihood for linear structural equation models with dependent errors
Authors: Wang Y. Samuel , Drton Mathias
Published: November 2017

We consider linear structural equation models that are associated with mixed graphs. The structural equations in these models only involve observed variables, but their idiosyncratic error terms are allowed to be correlated and non‐Gaussian. We propose empirical likelihood procedures for inference and suggest several modifications, including a profile likelihood, in order to improve tractability and performance of the resulting methods. Through simulations, we show that when the error distributions are non‐Gaussian, the use of empirical likelihood and the proposed modifications may increase statistical efficiency and improve assessment of significance. Copyright © 2017 John Wiley & Sons, Ltd.
Evaluation of (‐)‐[18F]Flubatine‐specific binding: Implications for reference region approaches
Authors: Bhatt Shivani , Hillmer Ansel T. , Nabulsi Nabeel , Matuskey David , Lim Keunpoong , Lin Shu‐Fei , Esterlis Irina , Carson Richard E. , Huang Yiyun , Cosgrove Kelly P.
Published: November 2017

We aimed to characterize changes in binding of (‐)‐[18F]Flubatine to α4β2*‐nicotinic acetylcholine receptors (α4β2*‐nAChRs) during a tobacco cigarette smoking challenge. Displacement of (‐)‐[18F]Flubatine throughout the brain was quantified as change in (‐)‐[18F]Flubatine distribution volume (VT), with particular emphasis on regions with low VT. Three tobacco smokers were imaged with positron emission tomography (PET) during a 210 min bolus‐plus‐constant infusion of (‐)‐[18F]Flubatine. A tobacco cigarette was smoked in the PET scanner ∼125 min after the start of (‐)‐[18F]Flubatine injection. Equilibrium analysis was used to estimate VT at baseline (90‐120 min) and after cigarette challenge (180‐210 min), at the time of greatest receptor occupancy by nicotine. Smoking reduced VT by 21 ± 9% (average ±SD) in corpus callosum, 17 ± 9% in frontal cortex, 36 ± 11% in cerebellum, and 22 ± 10% in putamen. The finding of displaceable (‐)‐[18F]Flubatine binding throughout the brain is an important consideration for reference region‐based quantification approaches with this tracer. We observed displacement of (‐)‐[18F]Flubatine binding to α4β2*‐nicotinic acetylcholine receptors in corpus callosum by a tobacco cigarette challenge. We conclude that reference region approaches utilizing corpus callosum should first perform careful characterization of displaceable (‐)‐[18F]Flubatine binding and nondisplaceable kinetics in this putative reference region.
In Praise of the “Ologies”: A Discussion of and Framework for Using Soft Skills to Sense and Influence Emergent Behaviors in Sociotechnical Systems
Authors: Donaldson William
Published: November 2017

Systems engineering has at its core the elucidation and instantiation of certain life‐cycle properties that help to define the system of interest. System engineers refer to these life‐cycle properties as the “ilities.” The ilities—repeatability, predictability, auditability, quality, reliability, flexibility, scalability, etc.—are nonfunctional requirements and properties that are usually used to evaluate the performance of the system, often after the system is in use. In sociotechnical systems the ilities are important, but there is another set of properties, concepts, and constructs which is derived from the social sciences and are at least as important, if not more so, than the ilities—the “ologies.” Sociotechnical enterprises represent a microsociological construct. The ologies emerge from the interaction of people in the systems and have profound implications for systems engineers and managers analyzing, designing, maintaining, and transforming such systems. Therefore, systems engineers must have an understanding of the disciplines from the social sciences, such as sociology and philosophy. This article serves as an introduction to the prevalence and importance of the social sciences to the discipline of systems engineering, offers one proposed framework for understanding the connected nature of the ologies, and provides systems‐relevant background and context provided by these sciences.
Formation of adult organs through metamorphosis in ascidians
Authors: Sasakura Yasunori , Hozumi Akiko
Published: November 2017

The representative characteristic of ascidians is their vertebrate‐like, tadpole shape at the larval stage. Ascidians lose the tadpole shape through metamorphosis to become adults with a nonmotile, sessile body and a shape generally considered distinct from that of vertebrates. Solitary ascidians including Ciona species are extensively studied to understand the developmental mechanisms of ascidians, and to compare these mechanisms with their counterparts in vertebrates. In these ascidian species, the digestive and circulatory systems are not well developed in the larval trunk and the larvae do not take food. This is in contrast with the inner conditions of vertebrate tadpoles, which have functional organs comparable to those of adults. The adult organs and tissues of these ascidians become functional during metamorphosis that is completed quickly, suggesting that the ascidian larvae of solitary species are a transient stage of development. We here discuss how the cells and tissues in the ascidian larval body are converted into those of adults. The hearts of ascidians and vertebrates use closely related cellular and molecular mechanisms that suggest their shared origin. Hox genes of ascidians are essential for forming adult endodermal structures. To fully understand the development and evolution of chordates, a complete elucidation of the mechanisms underlying the adult tissue/organ formation of ascidians will be needed. WIREs Dev Biol 2018, 7:e304. doi: 10.1002/wdev.304

This article is categorized under:

Comparative Development and Evolution > Body Plan Evolution

Early Embryonic Development > Development to the Basic Body Plan
Reliable benchmarking: requirements and solutions
Authors: Beyer Dirk , Löwe Stefan , Wendler Philipp
Published: November 2017

Benchmarking is a widely used method in experimental computer science, in particular, for the comparative evaluation of tools and algorithms. As a consequence, a number of questions need to be answered in order to ensure proper benchmarking, resource measurement, and presentation of results, all of which is essential for researchers, tool developers, and users, as well as for tool competitions. We identify a set of requirements that are indispensable for reliable benchmarking and resource measurement of time and memory usage of automatic solvers, verifiers, and similar tools, and discuss limitations of existing methods and benchmarking tools. Fulfilling these requirements in a benchmarking framework can (on Linux systems) currently only be done by using the cgroup and namespace features of the kernel. We developedBenchExec, a ready-to-use, tool-independent, and open-source implementation of a benchmarking framework that fulfills all presented requirements, making reliable benchmarking and resource measurement easy. Our framework is able to work with a wide range of different tools, has proven its reliability and usefulness in the International Competition on Software Verification, and is used by several research groups worldwide to ensure reliable benchmarking. Finally, we present guidelines on how to present measurement results in a scientifically valid and comprehensible way.
Genetic analysis of tropical quality protein maize (Zea mays L.) germplasm
Authors: Njeri Susan G. , Makumbi Dan , Warburton Marilyn L. , Diallo Alpha , Jumbo MacDonald B. , Chemining’wa George
Published: November 2017

Maize (Zea maysL.) is an important source of carbohydrates and protein in the diet in sub-Saharan Africa. The objectives of this study were to (i) estimate general (GCA) and specific combining abilities (SCA) of 13 new quality protein maize (QPM) lines in a diallel under stress and non-stress conditions, (ii) compare observed and predicted performance of QPM hybrids, (iii) characterize genetic diversity among the 13 QPM lines using single nucleotide polymorphism (SNP) markers and assess the relationship between genetic distance and hybrid performance, and (iv) assess diversity and population structure in 116 new QPM inbred lines as compared to eight older tropical QPM lines and 15 non-QPM lines. The GCA and SCA effects were significant for most traits under optimal conditions, indicating that both additive and non-additive genetic effects were important for inheritance of the traits. Additive genetic effects appeared to govern inheritance of most traits under optimal conditions and across environments. Non-additive genetic effects were more important for inheritance of grain yield but additive effects controlled most agronomic traits under drought stress conditions. Inbred lines CKL08056, CKL07292, and CKL07001 had desirable GCA effects for grain yield across drought stress and non-stress conditions. Prediction efficiency for grain yield was highest under optimal conditions. The classification of 139 inbred lines with 95 SNPs generated six clusters, four of which contained 10 or fewer lines, and 16 lines of mixed co-ancestry. There was good agreement between Neighbor Joining dendrogram and Structure classification. The QPM lines used in the diallel were nearly uniformly spread throughout the dendrogram. There was no relationship between genetic distance and grain yield in either the optimal or stressed environments in this study. The genetic diversity in mid-altitude maize germplasm is ample, and the addition of the QPM germplasm did not increase it measurably.
Comparing the Roles of Regulatory Oversight Bodies in Central and Eastern European Countries
Authors: STAROŇOVÁ Katarína
Published: November 2017

Currently, there is ongoing discussion about the role of regulatory oversight bodies in relation to the implementation of regulatory impact assessments (RIAs). In fact, one can witness a diffusion of regulatory oversight systems, including in CEE countries, where introduction of an RIA oversight body became part of the modernisation of the overall RIA process to become more effective. In fact, the regulatory oversight mechanism is seen as a tool for the instrumental role of regulation governance. However, this approach does not adequately explain the rationale behind setting up such a body; strategic and symbolic roles may be significant as well. This article first compares the manner in which oversight mechanisms have been institutionalised in five Central and East European countries: the Czech Republic, Estonia, Hungary, Slovakia and Slovenia. Second, it explores how differences in institutionalisation and operation shed light on understanding what stakeholders expect and understand in relation to control of RIA quality. The paper concludes that there are marked differences in regulatory oversight set-up and roles across Central and Eastern Europe, notably as a consequence of the presence or absence of internal learning.
Coherent clusters of inertial particles in homogeneous turbulence
Authors: Baker Lucia , Frankel Ari , Mani Ali , Coletti Filippo
Published: November 2017

Despite the widely acknowledged significance of turbulence-driven clustering, a clear topological definition of particle cluster in turbulent dispersed multiphase flows has been lacking. Here we introduce a definition of coherent cluster based on self-similarity, and apply it to distributions of heavy particles in direct numerical simulations of homogeneous isotropic turbulence, with and without gravitational acceleration. Clusters show self-similarity already at length scales larger than twice the Kolmogorov length, as indicated by the fractal nature of their surface and by the power-law decay of their size distribution. The size of the identified clusters extends to the integral scale, with average concentrations that depend on the Stokes number but not on the cluster dimension. Compared to non-clustered particles, coherent clusters show a stronger tendency to sample regions of high strain and low vorticity. Moreover, we find that the clusters align themselves with the local vorticity vector. In the presence of gravity, they tend to align themselves vertically and their fall speed is significantly different from the average settling velocity: for moderate fall speeds they experience stronger settling enhancement than non-clustered particles, while for large fall speeds they exhibit weakly reduced settling. The proposed approach for cluster identification leverages the Voronoï diagram method, but is also compatible with other tessellation techniques such as the classic box-counting method.
Music Education in 2017
Authors: FAUTLEY MARTIN
Published: November 2017

One of the fascinating things about the articles in the BJME is that they come from many different countries, with many different music education systems in place in them. Each country has its own way of doing things, and its own way of thinking about what music education means in its own circumstance. One of the issues we face today is that with increasing globalisation unique ways of musicking can be under threat from non-indigenous commercial interests. For music education this can have implications. One of the questions that it raises is about the purposes of music education. Is music education about passing on a historic culture whose existence is threatened? Is it about learning to play western classical instruments? Is it about learning to play pop and rock music? These are not simple questions, and they do not have simple answers.
Scientists Simulate New Mechanism of Fluid Flow in Earth’s Crust
Authors: Stanley Sarah
Published: November 2017

Three-dimensional high-performance computer modeling reveals the behavior of fluid transport waves generated by chemical reactions that take place during metamorphism.
Monitoring Coastal Zone Changes from Space
Authors: Cazenave A. , Le Cozannet G. , Benveniste Jérôme , Woodworth P. , Champollion N.
Published: November 2017

The resilience of coastal communities depends on an integrated, worldwide coastal monitoring effort. Satellite observations provide valuable data on global to local scales.
Signatures of Dinosaur Poop Found in Cretaceous Coal Seams
Authors: Kornei Katherine
Published: November 2017

Coal analysis suggests that plant-eating dinosaurs, by walking kilometers between their picnic areas and their toilets, distributed important nutrients widely and boosted ecosystem health.
Characterization of ecologically diverse viruses infecting co-occurring strains of cosmopolitan hyperhalophilic Bacteroidetes
Authors: Villamor Judith , Ramos-Barbero María Dolores , González-Torres Pedro , Gabaldón Toni , Rosselló-Móra Ramón , Meseguer Inmaculada , Martínez-García Manuel , Santos Fernando , Antón Josefa
Published: November 2017

Hypersaline environments close to saturation harbor the highest density of virus-like particles reported for aquatic systems as well as low microbial diversity. Thus, they offer unique settings for studying virus–host interactions in nature. However, no viruses have been isolated so far infecting the two most abundant inhabitants of these systems (that is, the euryarchaeon Haloquadratum walsbyi and the bacteroidetes Salinibacter ruber). Here, using three different co-occurring strains, we have isolated eight viruses infecting the ubiquitous S. ruber that constitute three new different genera (named as ‘Holosalinivirus’, ‘Kryptosalinivirus’ and ‘Kairosalinivirus’) according to their genomic traits, different host range, virus–host interaction capabilities and abundances in natural systems worldwide. Furthermore, to get a more complete and comprehensive view of S. ruber virus assemblages in nature, a microcosm experiment was set with a mixture of S. ruber strains challenged with a brine virus concentrate, and changes of viral populations were monitored by viral metagenomics. Only viruses closely related to kairosalinivirus (strictly lytic and wide host range) were enriched, despite their low initial abundance in the natural sample. Metagenomic analyses of the mesocosms allowed the complete recovery of kairosalinivirus genomes using an ad hoc assembly strategy as common viral metagenomic assembly tools failed despite their abundance, which underlines the limitations of current approaches. The increase of this type of viruses was accompanied by an increase in the diversity of the group, as shown by contig recruitment. These results are consistent with a scenario in which host range, not only virus and host abundances, is a key factor in determining virus fate in nature.
A dynamic microbial community with high functional redundancy inhabits the cold, oxic subseafloor aquifer
Authors: Tully Benjamin J , Wheat C Geoff , Glazer Brain T , Huber Julie A
Published: November 2017

The rock-hosted subseafloor crustal aquifer harbors a reservoir of microbial life that may influence global marine biogeochemical cycles. Here we utilized metagenomic libraries of crustal fluid samples from North Pond, located on the flanks of the Mid-Atlantic Ridge, a site with cold, oxic subseafloor fluid circulation within the upper basement to query microbial diversity. Twenty-one samples were collected during a 2-year period to examine potential microbial metabolism and community dynamics. We observed minor changes in the geochemical signatures over the 2 years, yet the microbial community present in the crustal fluids underwent large shifts in the dominant taxonomic groups. An analysis of 195 metagenome-assembled genomes (MAGs) were generated from the data set and revealed a connection between litho- and autotrophic processes, linking carbon fixation to the oxidation of sulfide, sulfur, thiosulfate, hydrogen, and ferrous iron in members of the Proteobacteria, specifically the Alpha-, Gamma- and Zetaproteobacteria, the Epsilonbacteraeota and the Planctomycetes. Despite oxic conditions, analysis of the MAGs indicated that members of the microbial community were poised to exploit hypoxic or anoxic conditions through the use of microaerobic cytochromes, such as cbb3- and bd-type cytochromes, and alternative electron acceptors, like nitrate and sulfate. Temporal and spatial trends from the MAGs revealed a high degree of functional redundancy that did not correlate with the shifting microbial community membership, suggesting functional stability in mediating subseafloor biogeochemical cycles. Collectively, the repeated sampling at multiple sites, together with the successful binning of hundreds of genomes, provides an unprecedented data set for investigation of microbial communities in the cold, oxic crustal aquifer.
Polymorphic regenerated silk fibers assembled through bioinspired spinning
Authors: Ling Shengjie , Qin Zhao , Li Chunmei , Huang Wenwen , Kaplan David L. , Buehler Markus J.
Published: November 2017

A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.
ATR kinase inhibition induces unscheduled origin firing through a Cdc7-dependent association between GINS and And-1
Authors: Moiseeva Tatiana , Hood Brian , Schamus Sandy , O’Connor Mark J. , Conrads Thomas P. , Bakkenist Christopher J.
Published: November 2017

ATR kinase activity slows replication forks and prevents origin firing in damaged cells. Here we describe proteomic analyses that identified mechanisms through which ATR kinase inhibitors induce unscheduled origin firing in undamaged cells. ATR-Chk1 inhibitor-induced origin firing is mediated by Cdc7 kinase through previously undescribed phosphorylations on GINS that induce an association between GINS and And-1. ATR-Chk1 inhibitor-induced origin firing is blocked by prior exposure to DNA damaging agents showing that the prevention of origin firing does not require ongoing ATR activity. In contrast, ATR-Chk1 inhibitor-induced origins generate additional replication forks that are targeted by subsequent exposure to DNA damaging agents. Thus, the sequence of administration of an ATR kinase inhibitor and a DNA damaging agent impacts the DNA damage induced by the combination. Our experiments identify competing ATR and Cdc7 kinase-dependent mechanisms at replication origins in human cells.
Creating nanoscale emulsions using condensation
Authors: Guha Ingrid F. , Anand Sushant , Varanasi Kripa K.
Published: November 2017

Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.
PINK1-mediated phosphorylation of LETM1 regulates mitochondrial calcium transport and protects neurons against mitochondrial stress
Authors: Huang En , Qu Dianbo , Huang Tianwen , Rizzi Nicoletta , Boonying Wassamon , Krolak Dorothy , Ciana Paolo , Woulfe John , Klein Christine , Slack Ruth S. , Figeys Daniel , Park David S.
Published: November 2017

Mutations in PTEN-induced kinase 1 (PINK1) result in a recessive familial form of Parkinson’s disease (PD). PINK1 loss is associated with mitochondrial Ca2+ mishandling, mitochondrial dysfunction, as well as increased neuronal vulnerability. Here we demonstrate that PINK1 directly interacts with and phosphorylates LETM1 at Thr192 in vitro. Phosphorylated LETM1 or the phospho-mimetic LETM1-T192E increase calcium release in artificial liposomes and facilitates calcium transport in intact mitochondria. Expression of LETM1-T192E but not LETM1-wild type (WT) rescues mitochondrial calcium mishandling in PINK1-deficient neurons. Expression of both LETM1-WT and LETM1-T192E protects neurons against MPP+–MPTP-induced neuronal death in PINK1 WT neurons, whereas only LETM1-T192E protects neurons under conditions of PINK1 loss. Our findings delineate a mechanism by which PINK1 regulates mitochondrial Ca2+ level through LETM1 and suggest a model by which PINK1 loss leads to deficient phosphorylation of LETM1 and impaired mitochondrial Ca2+ transport..
Rapid termination of the African Humid Period triggered by northern high-latitude cooling
Authors: Collins James A. , Prange Matthias , Caley Thibaut , Gimeno Luis , Beckmann Britta , Mulitza Stefan , Skonieczny Charlotte , Roche Didier , Schefuß Enno
Published: November 2017

The rapidity and synchrony of the African Humid Period (AHP) termination at around 5.5 ka are debated, and it is unclear what caused a rapid hydroclimate response. Here we analysed the hydrogen isotopic composition of sedimentary leaf-waxes (δDwax) from the Gulf of Guinea, a proxy for regional precipitation in Cameroon and the central Sahel-Sahara. Our record indicates high precipitation during the AHP followed by a rapid decrease at 5.8–4.8 ka. The similarity with a δDwax record from northern East Africa suggests a large-scale atmospheric mechanism. We show that northern high- and mid-latitude cooling weakened the Tropical Easterly Jet and, through feedbacks, strengthened the African Easterly Jet. The associated decrease in precipitation triggered the AHP termination and combined with biogeophysical feedbacks to result in aridification. Our findings suggest that extratropical temperature changes, albeit smaller than during the glacial and deglacial, were important in triggering rapid African aridification during the Holocene.
Prevalence and detection of low-allele-fraction variants in clinical cancer samples
Authors: Shin Hyun-Tae , Choi Yoon-La , Yun Jae Won , Kim Nayoung K. D. , Kim Sook-Young , Jeon Hyo Jeong , Nam Jae-Yong , Lee Chung , Ryu Daeun , Kim Sang Cheol , Park Kyunghee , Lee Eunjin , Bae Joon Seol , Son Dae Soon , Joung Je-Gun , Lee Jeeyun , Kim Seung Tae , Ahn Myung-Ju , Lee Se-Hoon , Ahn Jin Seok , Lee Woo Yong , Oh Bo Young , Park Yeon Hee , Lee Jeong Eon , Lee Kwang Hyuk , Kim Hee Cheol , Kim Kyoung-Mee , Im Young-Hyuck , Park Keunchil , Park Peter J. , Park Woong-Yang
Published: November 2017

Accurate detection of genomic alterations using high-throughput sequencing is an essential component of precision cancer medicine. We characterize the variant allele fractions (VAFs) of somatic single nucleotide variants and indels across 5095 clinical samples profiled using a custom panel, CancerSCAN. Our results demonstrate that a significant fraction of clinically actionable variants have low VAFs, often due to low tumor purity and treatment-induced mutations. The percentages of mutations under 5% VAF across hotspots in EGFR, KRAS, PIK3CA, and BRAF are 16%, 11%, 12%, and 10%, respectively, with 24% for EGFR T790M and 17% for PIK3CA E545. For clinical relevance, we describe two patients for whom targeted therapy achieved remission despite low VAF mutations. We also characterize the read depths necessary to achieve sensitivity and specificity comparable to current laboratory assays. These results show that capturing low VAF mutations at hotspots by sufficient sequencing coverage and carefully tuned algorithms is imperative for a clinical assay.
Strain-shear coupling in bilayer MoS2
Authors: Lee Jae-Ung , Woo Sungjong , Park Jaesung , Park Hee Chul , Son Young-Woo , Cheong Hyeonsik
Published: November 2017

Layered materials such as graphite and transition metal dichalcogenides have extremely anisotropic mechanical properties owing to orders of magnitude difference between in-plane and out-of-plane interatomic interaction strengths. Although effects of mechanical perturbations on either intralayer or interlayer interactions have been extensively investigated, mutual correlations between them have rarely been addressed. Here, we show that layered materials have an inevitable coupling between in-plane uniaxial strain and interlayer shear. Because of this, the uniaxial in-plane strain induces an anomalous splitting of the degenerate interlayer shear phonon modes such that the split shear mode along the tensile strain is not softened but hardened contrary to the case of intralayer phonon modes. We confirm the effect by measuring Raman shifts of shear modes of bilayer MoS2 under strain. Moreover, by analyzing the splitting, we obtain an unexplored off-diagonal elastic constant, demonstrating that Raman spectroscopy can determine almost all mechanical constants of layered materials.
Observation of transverse spin Nernst magnetoresistance induced by thermal spin current in ferromagnet/non-magnet bilayers
Authors: Kim Dong-Jun , Jeon Chul-Yeon , Choi Jong-Guk , Lee Jae Wook , Surabhi Srivathsava , Jeong Jong-Ryul , Lee Kyung-Jin , Park Byong-Guk
Published: November 2017

Electric generation of spin current via spin Hall effect is of great interest as it allows an efficient manipulation of magnetization in spintronic devices. Theoretically, pure spin current can be also created by a temperature gradient, which is known as spin Nernst effect. Here, we report spin Nernst effect-induced transverse magnetoresistance in ferromagnet/non-magnetic heavy metal bilayers. We observe that the magnitude of transverse magnetoresistance in the bilayers is significantly modified by heavy metal and its thickness. This strong dependence of transverse magnetoresistance on heavy metal evidences the generation of thermally induced pure spin current in heavy metal. Our analysis shows that spin Nernst angles of W and Pt have the opposite sign to their spin Hall angles. Moreover, our estimate implies that the magnitude of spin Nernst angle would be comparable to that of spin Hall angle, suggesting an efficient generation of spin current by the spin Nernst effect.
Anisotropic attosecond charge carrier dynamics and layer decoupling in quasi-2D layered SnS2
Authors: Eads Calley N. , Bandak Dmytro , Neupane Mahesh R. , Nordlund Dennis , Monti Oliver L. A.
Published: November 2017

Strong quantum confinement effects lead to striking new physics in two-dimensional materials such as graphene or transition metal dichalcogenides. While spectroscopic fingerprints of such quantum confinement have been demonstrated widely, the consequences for carrier dynamics are at present less clear, particularly on ultrafast timescales. This is important for tailoring, probing, and understanding spin and electron dynamics in layered and two-dimensional materials even in cases where the desired bandgap engineering has been achieved. Here we show by means of core–hole clock spectroscopy that SnS2 exhibits spin-dependent attosecond charge delocalization times (τdeloc) for carriers confined within a layer, τdeloc < 400 as, whereas interlayer charge delocalization is dynamically quenched in excess of a factor of 10, τdeloc > 2.7 fs. These layer decoupling dynamics are a direct consequence of strongly anisotropic screening established within attoseconds, and demonstrate that important two-dimensional characteristics are also present in bulk crystals of van der Waals-layered materials, at least on ultrafast timescales.
Thermal crumpling of perforated two-dimensional sheets
Authors: Yllanes David , Bhabesh Sourav S. , Nelson David R. , Bowick Mark J.
Published: November 2017

Thermalized elastic membranes without distant self-avoidance are believed to undergo a crumpling transition when the microscopic bending stiffness is comparable to kT, the scale of thermal fluctuations. Most potential physical realizations of such membranes have a bending stiffness well in excess of experimentally achievable temperatures and are therefore unlikely ever to access the crumpling regime. We propose a mechanism to tune the onset of the crumpling transition by altering the geometry and topology of the sheet itself. We carry out extensive molecular dynamics simulations of perforated sheets with a dense periodic array of holes and observe that the critical temperature is controlled by the total fraction of removed area, independent of the precise arrangement and size of the individual holes. The critical exponents for the perforated membrane are compatible with those of the standard crumpling transition.
Membrane curvature induced by proximity of anionic phospholipids can initiate endocytosis
Authors: Hirama Takashi , Lu Stella M. , Kay Jason G. , Maekawa Masashi , Kozlov Michael M. , Grinstein Sergio , Fairn Gregory D.
Published: November 2017

The plasma membrane is uniquely enriched in phosphatidylserine (PtdSer). This anionic phospholipid is restricted almost exclusively to the inner leaflet of the plasmalemma. Because of their high density, the headgroups of anionic lipids experience electrostatic repulsion that, being exerted asymmetrically, is predicted to favor membrane curvature. We demonstrate that cholesterol limits this repulsion and tendency to curve. Removal of cholesterol or insertion of excess PtdSer increases the charge density of the inner leaflet, generating foci of enhanced charge and curvature where endophilin and synaptojanin are recruited. From these sites emerge tubules that undergo fragmentation, resulting in marked endocytosis of PtdSer. Shielding or reduction of the surface charge or imposition of outward membrane tension minimized invagination and PtdSer endocytosis. We propose that cholesterol associates with PtdSer to form nanodomains where the headgroups of PtdSer are maintained sufficiently separated to limit spontaneous curvature while sheltering the hydrophobic sterol from the aqueous medium.
Influenza virus genome reaches the plasma membrane via a modified endoplasmic reticulum and Rab11-dependent vesicles
Authors: de Castro Martin Isabel Fernández , Fournier Guillaume , Sachse Martin , Pizarro-Cerda Javier , Risco Cristina , Naffakh Nadia
Published: November 2017

Transport of neo-synthesized influenza A virus (IAV) viral ribonucleoproteins (vRNPs) from the nucleus to the plasma membrane involves Rab 11 but the precise mechanism remains poorly understood. We used metal-tagging and immunolabeling to visualize viral proteins and cellular endomembrane markers by electron microscopy of IAV-infected cells. Unexpectedly, we provide evidence that the vRNP components and the Rab11 protein are present at the membrane of a modified, tubulated endoplasmic reticulum (ER) that extends all throughout the cell, and on irregularly coated vesicles (ICVs). Some ICVs are found very close to the ER and to the plasma membrane. ICV formation is observed only in infected cells and requires an active Rab11 GTPase. Against the currently accepted model in which vRNPs are carried onto Rab11-positive recycling endosomes across the cytoplasm, our findings reveal that the endomembrane organelle that is primarily involved in the transport of vRNPs is the ER.
Structural basis for Ragulator functioning as a scaffold in membrane-anchoring of Rag GTPases and mTORC1
Authors: Zhang Tianlong , Wang Rong , Wang Zhijing , Wang Xiangxiang , Wang Fang , Ding Jianping
Published: November 2017

Amino acid-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) is mediated by Rag GTPases, which are recruited to the lysosome by the Ragulator complex consisting of p18, MP1, p14, HBXIP and C7orf59; however, the molecular mechanism is elusive. Here, we report the crystal structure of Ragulator, in which p18 wraps around the MP1-p14 and C7orf59-HBXIP heterodimers and the interactions of p18 with MP1, C7orf59, and HBXIP are essential for the assembly of Ragulator. There are two binding sites for the Roadblock domains of Rag GTPases: helix α1 of p18 and the two helices side of MP1-p14. The interaction of Ragulator with Rag GTPases is required for their cellular co-localization and can be competitively inhibited by C17orf59. Collectively, our data indicate that Ragulator functions as a scaffold to recruit Rag GTPases to lysosomal membrane in mTORC1 signaling.
Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques
Authors: Wang Yi , Zhu Dapeng , Wu Yang , Yang Yumeng , Yu Jiawei , Ramaswamy Rajagopalan , Mishra Rahul , Shi Shuyuan , Elyasi Mehrdad , Teo Kie-Leong , Wu Yihong , Yang Hyunsoo
Published: November 2017

Topological insulators with spin-momentum-locked topological surface states are expected to exhibit a giant spin-orbit torque in the topological insulator/ferromagnet systems. To date, the topological insulator spin-orbit torque-driven magnetization switching is solely reported in a Cr-doped topological insulator at 1.9 K. Here we directly show giant spin-orbit torque-driven magnetization switching in a Bi2Se3/NiFe heterostructure at room temperature captured using a magneto-optic Kerr effect microscope. We identify a large charge-to-spin conversion efficiency of ~1–1.75 in the thin Bi2Se3 films, where the topological surface states are dominant. In addition, we find the current density required for the magnetization switching is extremely low, ~6 × 105 A cm–2, which is one to two orders of magnitude smaller than that with heavy metals. Our demonstration of room temperature magnetization switching of a conventional 3d ferromagnet using Bi2Se3 may lead to potential innovations in topological insulator-based spintronic applications.
A mechanism for FtsZ-independent proliferation in Streptomyces
Authors: Santos-Beneit Fernando , Roberts David M. , Cantlay Stuart , McCormick Joseph R. , Errington Jeff
Published: November 2017

The central player in bacterial cell division, FtsZ, is essential in almost all organisms in which it has been tested, with the most notable exception being Streptomyces. Streptomycetes differ from many bacteria in growing from the cell tip and undergoing branching, similar to filamentous fungi. Here we show that limited cell damage, either mechanical or enzymatic, leads to near complete destruction of mycelial microcolonies of a Streptomyces venezuelae ftsZ mutant. This result is consistent with a lack of ftsZ-dependent cross-walls and may be inconsistent with a recently proposed role for membrane structures in the proliferation of ftsZ mutants in other Streptomyces species. Rare surviving fragments of mycelium, usually around branches, appear to be the preferred sites of resealing. Restoration of growth in hyphal fragments of both wild-type and ftsZ mutant hyphae can occur at multiple sites, via branch-like outgrowths containing DivIVA protein at their tips. Thus, our results highlight branching as a means of FtsZ-independent cell proliferation.
Observation of the exceptional point in cavity magnon-polaritons
Authors: Zhang Dengke , Luo Xiao-Qing , Wang Yi-Pu , Li Tie-Fu , You J. Q.
Published: November 2017

Magnon–polaritons are hybrid light–matter quasiparticles originating from the strong coupling between magnons and photons. They have emerged as a potential candidate for implementing quantum transducers and memories. Owing to the dampings of both photons and magnons, the polaritons have limited lifetimes. However, stationary magnon–polariton states can be reached by a dynamical balance between pumping and losses, so the intrinsically nonequilibrium system may be described by a non-Hermitian Hamiltonian. Here we design a tunable cavity quantum electrodynamics system with a small ferromagnetic sphere in a microwave cavity and engineer the dissipations of photons and magnons to create cavity magnon–polaritons which have non-Hermitian spectral degeneracies. By tuning the magnon–photon coupling strength, we observe the polaritonic coherent perfect absorption and demonstrate the phase transition at the exceptional point. Our experiment offers a novel macroscopic quantum platform to explore the non-Hermitian physics of the cavity magnon–polaritons.
Total morphosynthesis of biomimetic prismatic-type CaCO3 thin films
Authors: Xiao Chuanlian , Li Ming , Wang Bingjun , Liu Ming-Feng , Shao Changyu , Pan Haihua , Lu Yong , Xu Bin-Bin , Li Siwei , Zhan Da , Jiang Yuan , Tang Ruikang , Liu Xiang Yang , Cölfen Helmut
Published: November 2017

Biomimetic mineralization can lead to advanced crystalline composites with common chemicals under ambient conditions. An exceptional example is biomimetic nacre with its superior fracture toughness. The synthesis of the prismatic layer with stiffness and wear resistance nonetheless remains an elusive goal. Herein, we apply a biomimetic mineralization method to grow prismatic-type CaCO3 thin films, mimicking their biogenic counterparts found in mollusk shells with a three-step pathway: coating a polymer substrate, deposition of a granular transition layer, and mineralization of a prismatic overlayer. The synthetic prismatic overlayers exhibit structural similarity and comparable hardness and Young’s modulus to their biogenic counterparts. Furthermore, employment of a biomacromolecular soluble additive, silk fibroin, in fabrication of the prismatic thin films leads to micro-/nano-textures with enhanced toughness and emerging under-water superoleophobicity. This study highlights the crucial role of the granular transition layer in promoting competition growth of the prismatic layer.