bluuebunny/crossref_metadata_2025 huggingface dataset:
RNF4—A Paradigm for SUMOylation‐Mediated Ubiquitination
Authors: Kumar Ramesh , Sabapathy Kanaga
Published: October 2019

Covalent modifications by Small Ubiquitin‐like MOdifier (SUMO) and ubiquitin conjugation are now recognized as independent posttranslational modifications (PTMs) employed by cells to reversibly regulate cellular signaling. SUMOylation in particular has emerged as a crucial cellular mechanism involved in multiple pathologies, including cancers, cardiovascular diseases, immunological and neurological disorders, as well as aging. Convergence of these two PTMs result in the ubiquitination of SUMOylated proteins, adding complexity in the modulation of protein functions. The SUMO‐Targeted Ubiquitin Ligases (STUbL) mediate this process, and RNF4, the mammalian STUbL, has been at the forefront in the understanding of this phenomenon. It has been shown to play important roles in a variety of cellular events, ranging from the maintenance of genomic integrity and hence, oncogenesis, to a role in development. Recent identification of direct and indirect RNF4 targets has revealed that the SUMOylation machinery is in itself targeted by RNF4, highlighting the complex nature of the signaling circuitry tightly regulating these processes. This review will touch upon both SUMOylation and ubiquitination, and will focus on how RNF4, which is at the heart of both these PTMs, modulates cellular signaling and promotes protein degradation. Moreover, the potential of therapeutically targeting RNF4 to improve cancer treatment is also explored.
A new tricrystalline triblock terpolymer by combining polyhomologation and ring‐opening polymerization. synthesis and thermal properties
Authors: Ladelta Viko , Zapsas George , Gnanou Yves , Hadjichristidis Nikos
Published: October 2019

New tricrystalline triblock terpolymers, polyethylene‐block‐poly(ε‐caprolactone)‐block‐poly(L‐lactide) (PE‐b‐PCL‐b‐PLLA), were synthesized by ROP of ε‐caprolactone (CL) and L‐lactide (LLA) from linear ω‐hydroxyl polyethylene (PE‐OH) macroinitiators. The linear PE‐OH macroinitiators were prepared by C1 polymerization of methylsulfoxonium methylide (polyhomologation). Tin(II) 2‐ethylhexanoate was used as the catalyst for the sequential ROP of CL and LLA in one‐pot polymerization at 85 °C in toluene (PE‐OH macroinitiators are soluble in toluene at 80 °C). 1H NMR spectra confirmed the formation of PE‐b‐PCL‐b‐PLLA triblock terpolymers through the appearance of the characteristic proton peaks of each block. GPC traces showed the increase in the number average molecular weight from PE‐OH macroinitiator to PE‐b‐PCL, and PE‐b‐PCL‐b‐PLLA corroborating the successful synthesis. The existence of three crystalline blocks was proved by DSC and XRD spectroscopy. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2450–2456
Identification of molecular vibrations associated with tacticity in polypropylene: Density functional theory‐based simulations
Authors: Mitra Nilanjan , Prasad Dipak , Banerjee Susanta
Published: October 2019

The polymerization of vinyl monomers with achiral carbon center forms polymers with different spatial arrangements resulting in products with a different set of mechanical and thermal properties. Therefore, control of the tacticity (stereochemistry) is of major importance for controlling the polymer properties. It is possible to manipulate the polymer stereoregularity through the application of appropriate synthetic protocols. However, the polymers obtained using these protocols are not perfect, and thereby, it is essential to know the amount of different stereoregular units in a polymer mass. Generally, extensive NMR techniques and vibrational spectroscopy are used in this regard. To investigate further, a detailed DFT has been employed in this manuscript for syndio and isotactic polypropylene. The DFT allows generation of the vibrational spectra in the far‐infrared (0–400 cm−1) region, demonstrating the distinct nature of both types of polymers. The vibrational spectra for pure syndio and isotactic polypropylene as well as their conformer defects have been identified in this study. These studies of vibration spectra in the far‐infrared regime can be used to identify signatures of pure racemo and meso dyads along with the type of conformer defects present in pristine varieties. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1378–1385
Cog in the wheel: Resource release and the scope of interdependencies in corporate adjustment activities
Authors: Keum Dongil D.
Published: October 2019

Research Summary

This study characterizes and tests interdependencies in corporate activities used to adjust resources and implement change. Because each activity contributes only a partial result and depends on others to complete an intended change, constraining one can create a bottleneck that traps multiple other activities. For my empirical analysis, I leverage the staggered adoptions of employment protection laws intended to constrain one specific adjustment to one specific resource: dismissing employees. The constraint, however, not only affects the contraction but also the expansion in labor as well as capital investments, acquisition, divestiture, CEO turnover, and other adjustments, and increases (shortens) the persistence of negative (positive) performance. The expansive interdependencies are critical to understanding firm rigidity and resilience, implementation failures, and the persistence of firm performance.

Managerial Summary

This study shows how executing even a seemingly straightforward improvement requires piecing together a series of interdependent corporate strategic activities. As a result, a constraint on just one is sufficient to foil a successful firm response. Using changes in employment laws, I show that a firm's ability to dismiss employees not only affects firing, but also hiring, capital investments, acquisition, divestiture, and CEO turnover, and increases (shortens) the persistence of negative (positive) performance. Underestimating the complex and interdependent nature of these activities can lead to bias‐for‐action and contribute to implementation failures, such as cost overruns, schedule delays, and a post‐merger integration process that fails to realize expected synergies.
Design of Multifunctional Fluorescent Hybrid Materials Based on SiO2 Materials and Core–Shell Fe3O4@SiO2 Nanoparticles for Metal Ion Sensing
Authors: Chatterjee Sobhan , Li Xiang‐Shuai , Liang Feng , Yang Ying‐Wei
Published: October 2019

Hybrid fluorescent materials constructed from organic chelating fluorescent probes and inorganic solid supports by covalent interactions are a special type of hybrid sensing platform that has gained much interest in the context of metal ion sensing applications owing to their excellent advantages, recyclability, and solubility/dispersibility in particular, as compared with single organic fluorescent molecules. In recent decades, SiO2 materials and core–shell Fe3O4@SiO2 nanoparticles have become important inorganic solid materials and have been used as inorganic solid supports to hybridize with organic fluorescent receptors, resulting in multifunctional fluorescent hybrid systems for potential applications in sensing and related research fields. Therefore, recent progress in various fluorescent‐group‐functionalized SiO2 materials is reviewed, with a focus on mesoporous silica nanoparticles and core–shell Fe3O4@SiO2 nanoparticles, as interesting fluorescent organic–inorganic hybrid materials for sensing applications toward essential and toxic metal ions. Selective examples of other types of silica/silicon materials, such as periodic mesoporous organosilicas, solid SiO2 nanoparticles, fibrous silica spheres, silica nanowires, silica nanotubes, and silica hollow microspheres, are also mentioned. Finally, relevant perspectives of metal‐ion‐sensing‐oriented silica‐fluorescent probe hybrid materials are provided.
Behavioral fingerprinting of Internet‐of‐Things devices
Authors: Bezawada Bruhadeshwar , Ray Indrakshi , Ray Indrajit
Published: October 2019

Rapid advances in the Internet‐of‐Things (IoT) domain have led to the development of several useful and interesting devices that have enhanced the quality of home living and industrial automation. The vulnerabilities in the IoT devices have rendered them susceptible to compromise and forgery. The problem of device authentication, that is, the question of whether a device's identity is what it claims to be, is still an open problem. Device fingerprinting seems to be a promising authentication mechanism. Device fingerprinting profiles a device based on information available about the device and generate a robust, verifiable and unique identity for the device. Existing approaches for device fingerprinting may not be feasible or cost‐effective for the IoT domain due to the resource constraints and heterogeneity of the IoT devices. Due to resource and cost constraints, behavioral fingerprinting provides promising directions for fingerprinting IoT devices. Behavioral fingerprinting allows security researchers to understand the behavioral profile of a device and to establish some guidelines regarding the device operations. In this article, we discuss existing approaches for behavioral fingerprinting of devices in general and evaluate their applicability for IoT devices. Furthermore, we discuss potential approaches for fingerprinting IoT devices and give an overview of some of the preliminary attempts to fingerprint IoT devices. We conclude by highlighting the future research directions for fingerprinting in the IoT domain.

This article is categorized under:

Application Areas > Science and Technology

Application Areas > Internet

Technologies > Machine Learning

Application Areas > Industry Specific Applications
Optogenetic Reconstitution: Light-Induced Assembly of Protein Complexes and Simultaneous Visualization of Their Intracellular Functions
Authors: Kiyomitsu Tomomi
Published: October 2019

Dynamic behaviors of cells require optimized functions and regulations of protein complexes within a cell. In vitro reconstitution is a powerful method to dissect the molecular functions and structure of reconstituted protein complexes. However, owing to the difficulties associated with in vitro reconstitution of complicated supra-molecular complexes, such as the mitotic spindle and cortical force-generating machinery, key molecular features underlying their functions and regulations are not fully understood. Recently, several light-inducible dimerization tools have been developed to control localization of target proteins within a cell in a spatiotemporally controlled manner. In this chapter, I have summarized the recent progress in optogenetic tools and fluorescent proteins/probes and have determined strategies to achieve light-induced in cell reconstitution of protein complexes coupled with visualization of its downstream events. Moreover, I have discussed the advantages and potential of the optogenetic reconstitution system in diverse cell and developmental biology fields.
Investigating Evolutionary Rate Variation in Bacteria
Authors: Gibson Beth , Eyre-Walker Adam
Published: October 2019

Rates of molecular evolution are known to vary between species and across all kingdoms of life. Here, we explore variation in the rate at which bacteria accumulate mutations (accumulation rates) in their natural environments over short periods of time. We have compiled estimates of the accumulation rate for over 34 species of bacteria, the majority of which are pathogens evolving either within an individual host or during outbreaks. Across species, we find that accumulation rates vary by over 3700-fold. We investigate whether accumulation rates are associated to a number potential correlates including genome size, GC content, measures of the natural selection and the time frame over which the accumulation rates were estimated. After controlling for phylogenetic non-independence, we find that the accumulation rate is not significantly correlated to any factor. Furthermore, contrary to previous results, we find that it is not impacted by the time frame of which the estimate was made. However, our study, with only 34 species, is likely to lack power to detect anything but large effects. We suggest that much of the rate variation may be explained by differences between species in the generation time in the wild.
Breast Reconstruction with a Tissue Engineering and Regenerative Medicine Approach (Systematic Review)
Authors: Donnely E. , Griffin M. , Butler P. E.
Published: October 2019

Current techniques for breast reconstruction include an autologous-tissue flap or an implant-based procedure, although both can impose further morbidity. This systematic review aims to explore the existing literature on breast reconstruction using a tissue engineering approach; conducted with the databases Medline and Embase. A total of 28 articles were included, mainly comprising of level-5 evidence within vitroand animal studies focusing on utilizing scaffolds to support the migration and growth of new tissue; scaffolds can be either biological or synthetic. Biological scaffolds were composed of collagen or a decellularized tissue matrix scaffold. Synthetic scaffolds were primarily composed of polymers with customisable designs, adjusting the internal morphology and pore size. Implanting cells, including adipose-derived stem cells, with combined use of basic fibroblast growth factor has been studied in an attempt to enhance tissue regeneration. Lately, a level-4 evidence human case series was reported; successfully regenerating 210 mL of tissue using an arterio-venous pedicled fat flap within a tissue engineering chamber implanted on the chest wall. Further research is required to evaluate whether the use of cells and other growth factors could adjust the composition of regenerated tissue and improve vascularity; the latter a major limiting factor for creating larger volumes of tissue.
Solar Eclipses and the Surface Properties of Water
Authors: Fuchs Elmar C. , Oudakker Gerrit , Justinek Martin , Dyer Nigel , Woisetschläger Jakob , Godines Kevin , Mäder Matthias , Freund Friedemann T.
Published: October 2019

During four solar eclipse events (two annular, one total and one partial) a correlation was observed between a change in water surface tension and the magnitude of the optical coverage. During one eclipse, evaporation experiments were carried out which showed a reduction in water evaporation at the same time as a rise in the surface tension. The changes did not occur on a day without a solar eclipse and are not correlated to changes in temperature, pressure, humidity of the environment. The effects are delayed by 20, 85, 30 and 37 min, respectively, compared to the maximum eclipse. Possible mechanisms responsible for this effect are presented, the most likely hypothesis being reduced water/muon interaction due to solar wind and cosmic radiation blocking during an eclipse. As an alternative hypotheses, we propose a novel neutrino/water interaction and overview of other, less likely mechanisms.
Comparison of the antimicrobial activity of propolis extracts obtained by means of various extraction methods
Authors: Pobiega Katarzyna , Kraśniewska Karolina , Derewiaka Dorota , Gniewosz Małgorzata
Published: September 2019

The objective of the study was to compare the antimicrobial activities of ethanolic propolis extracts obtained using different extraction methods. Extraction of propolis was carried out using 70% ethanol, propolis to ethanol ratios of 1:10 and 1:5, extraction times of 1 or 7 days, and shaking extraction (SE), ultrasound-assisted extraction (UAE), and ultrasound-assisted shaking extraction (SUAE) methods. A total of 12 propolis extract lyophilizates were obtained. Samples were tested for extraction yield and for total phenol content by the Folin–Ciocalteau colourimetric method, and total flavonoid content using a spectrophotometric method. GLC/MS was used for the identification of chemical compounds in selected extract lyophilizates. Antimicrobial activity against selected bacterial and fungal species was assessed using the disk diffusion method. Propolis extracts obtained as the result of 1-day and 7-day shaking extraction followed by 20 min of ultrasound-assisted extraction (SUAE) had better antimicrobial properties as compared to those obtained by SE or UAE alone. SE and UAE gave lower extraction yields as well as lower phenol and flavonoid contents compared to SUAE. No differences were observed with regard to the qualitative composition of extracts obtained by any of the methods. It is best to obtain the extract using the combined method of 1-day extraction and 20-min sonication.
Fit for purpose? Assessing Collaborative Innovation in the European Network for Prosecutors for the Environment
Authors: MARTINIUS Evelijn , MASTENBROEK Ellen
Published: October 2019

European Administrative Networks are expected to strengthen the national enforcement of European legislation. The idea is that these networks organise national civil servants, and allow them to exchange best practices, negotiate guidelines and develop inventive solutions to common challenges faced during the implementation and enforcement of European Union regulations. This paper proposes a framework to evaluate European Administrative Networks on their potential to spur collaborative innovation concerning national enforcement of this common regulation. The framework is then applied to a particular network, the European Network for Prosecutors of the Environment. Results show that this network can be considered a resource for collaborative innovation.
Transient and slim versus recurrent and fat: Random walks and the trees they grow
Authors: Iacobelli Giulio , Figueiredo Daniel R. , Neglia Giovanni
Published: October 2019

The no restart random walk (NRRW) is a random network growth model driven by a random walk that builds the graph while moving on it, adding and connecting a new leaf node to the current position of the walker every s steps. We show a fundamental dichotomy in NRRW with respect to the parity of s: for

${s}=1$

we prove that the random walk is transient and non-leaf nodes have degrees bounded above by an exponential distribution; for s even we prove that the random walk is recurrent and non-leaf nodes have degrees bounded below by a power law distribution. These theoretical findings highlight and confirm the diverse and rich behaviour of NRRW observed empirically.
Reproductive sublethal effects of macrocyclic lactones and synthetic pyrethroids on the dung beetle Onthophagus similis
Authors: Weaving H. , Sands B. , Wall R.
Published: October 2019

Dung-colonizing beetles provide a range of ecosystem services in farmland pasture systems. However, such beetles are declining in Northern temperate regions. This may, in part, be due to the widespread use of macrocyclic lactones (MLs) and synthetic pyrethroids (SPs) in livestock farming. These chemicals are used to control pests and parasites of cattle; the residues of which are excreted in dung at concentrations toxic to insects. While the lethal effects of such residues are well known, sublethal effects are less understood. Any effects, however, may have important consequences for beetle populations, particularly if they affect reproduction. To investigate, the impact of ML and SP exposure on the reproductive output of Onthophagus similis (Scriba), a Northern temperate dung beetle species, was examined. In laboratory trials, field-collected adult O. similis exposed to the ML ivermectin at 1 ppm (wet weight) over a period of 3 weeks had smaller oocytes (p = 0.016), smaller fat bodies and reduced motility compared to the control. In a farm-level investigation, cattle dung-baited pitfall trapping was undertaken on 23 beef cattle farms in SW England, which either used MLs (n = 9), SPs (n = 7) or neither chemical (n = 7). On farms that used no MLs or SPs, 24.2% of females caught were gravid. However, on farms that used MLs no gravid females were caught, and only 1% of the beetles caught on farms using SPs were gravid (p < 0.001). The association between ML and SP use and impaired reproductive output suggests that the use of such chemicals is likely to be ecologically damaging.
Retrospective Voting and the Polarization of Available Alternatives
Authors: Stiers Dieter , Dassonneville Ruth
Published: October 2019

Government cohesiveness is known to moderate retrospective voting. While previous work on this topic has focused on characteristics of the government, we build on the literature on clarity of responsibility and the literature on valence to argue that the extent to which government and opposition are ideologically distinct also moderates retrospective voting. Two alternative expectations follow from these two theoretical perspectives. While the clarity of responsibility framework leads to the expectation that a larger difference between government and opposition will strengthen retrospective voting, the valence literature presumes that retrospective voting is stronger when ideological differences are small. Using the data of the Comparative Study of Electoral Systems (CSES) project, we find evidence that is in line with the clarity of responsibility framework: the higher the degree of ideological polarization between government and opposition, the larger the effect of retrospective performance evaluations on the vote.
War, International Finance, and Fiscal Capacity in the Long Run
Authors: Queralt Didac
Published: September 2019

In this article I revisit the relationship between war and state making in modern times by focusing on two prominent types of war finance: taxes and foreign loans. Financing war with tax money enhances the capacity to assess wealth and monitor compliance, namely fiscal capacity. Tax-financed war facilitates the adoption of power-sharing institutions, which transform taxation into a non-zero-sum game, carrying on the effect of war in the long run. Financing war with external capital does not contribute to long-term fiscal capacity if borrowers interrupt debt service and, as part of the default settlement, war debt is condoned or exchanged for nontax revenue. The empirical evidence draws from war around the world as early as 1816. Results suggest that globalization of capital markets in the nineteenth century undermined the association between war, state making, and political reform.
Topology of voids and channels in selected porphyrinic compounds
Authors: Cook Lawrence P. , Brewer Greg A. , Siderius Daniel , Wong-Ng Winnie
Published: October 2019

Porphyrinic compounds are of increasing interest to the materials science community, yet little attention has been paid to crystallographically controlled voids and channels in these materials. We have conducted an initial survey of the voids and channels in a random subset of 1000 porphyrinic compounds with known crystal structures. From calculations using a rolling-probe subroutine, we have found that about 5% of these compounds have line-of-sight channels, which differ in their topology depending on the crystallography. A small but significant number of porphyrinic compounds have calculated void contents of >25 volume %. We discuss in detail the void and channel characteristics, including pore-size distribution, of four representative compounds, with technological implications.
The organisation and structure of rhotics in American English rhymes
Authors: Walker Rachel , Proctor Michael
Published: October 2019

Language-specific maximal size restrictions on syllables have been defined using frames such as moraic structure. In General American English, a trimoraic syllable template makes largely successful predictions about contexts where tense/lax vowel contrasts are neutralised, but neutralisation preceding a coda rhotic has not been adequately explained. We attribute the apparent special properties of coda /ɹ/ to two characteristics of its representation, informed by our articulatory investigation: sequential coordination of dorsal and coronal subsegmental units and a high blending strength specification, corresponding to high coarticulatory dominance. Characteristics of coda laterals are compared. Our approach employs phonological representations where sequencing is encoded directly among subsegments, and coordination is sensitive to strength. Mora assignment is computed over sequencing of subsegments, predicting that complex segments may be bimoraic. The account brings phonotactics for rhymes with postvocalic liquids into line with the trimoraic template, and supports representing coordination and strength at the subsegmental level.
Tod innerhalb von Stunden
Authors: Kindler Rahel Maria , Kuster Marc , Madörin Doris
Published: October 2019

Zusammenfassung. Die klinische Bandbreite einer invasiven Erkrankung mit Meningokokken ist gross, am häufigsten manifestiert sich das klinische Bild einer Meningitis und/oder Sepsis. Der Schweregrad einer Erkrankung mit Meningokokken reicht von einfacher Bakteriämie, assoziiert mit milden, unspezifischen Symptomen, bis hin zur fulminanten Sepsis mit Multiorganversagen und Tod, was in ungefähr 10–15 % aller Fälle vorkommt. Gelegentlich können auch nur lokale Infektionen (z.B. septische Arthritis oder Konjunktivitis) oder selten chronische Verläufe (prolongiertes, intermittierendes Fieber, Ausschlag, Gelenk- und Kopfschmerzen) die einzige klinische Manifestation darstellen – diese können aber genauso gut zur disseminierten fulminanten Erkrankung führen. Unser Fall zeigt den tragischen Verlauf einer fulminanten Meningokokkensepsis mit rascher Todesfolge.
The Seagoing Scientist's Toolbox: Integrated Methods for Quality Control of Marine Geophysical Data at Sea
Authors: Hamilton Michael , Wessel Paul , Luis Joaquim , Taylor Brian , Ko Youngtak
Published: October 2019

We announce a new and integrated system for planning and executing marine geophysical surveys and for scrutinizing and visualizing incoming shipboard data. The system incorporates free software designed for use by scientists and shipboard operators and pertains to underway geophysics and multibeam sonar surveys. Regarding underway data, a crucial first step in the approach is to reduce and merge incoming center beam depth, gravity, and towed magnetic data with navigation, then reformat to the standard exchange format. We are then able to apply established quality control methods including along‐track and cross‐track analyses to identify error sources and to incrementally build the candidate archive file as new data are acquired. Regarding multibeam data, these are subjected to both an automated error removal scheme for quick visualization and to subsequent ping editing in detail. The candidate archive file and sonar data are automatically and periodically updated and adapted for display in Google Earth, wherein survey planning is also carried out. Data layers are also updated automatically in Google Earth, allowing scientists to focus on visual inspection and interpretation of incoming data. By visualizing underway and sonar data together with reference gravity, magnetic, and bathymetry grids in Google Earth, data familiarity is enhanced and the likelihood of noticing extreme errors increased. We hope scientists will embrace these techniques so that each data set being submitted to a data repository is vetted by the seagoing science party.
Seasonal, Spring‐Neap, and Tidal Variation in Cohesive Sediment Transport Parameters in Estuarine Shallows
Authors: Allen Rachel M. , Lacy Jessica R. , Stacey Mark T. , Variano Evan A.
Published: October 2019

Numerical models for predicting sediment concentrations and transport rely on parameters such as settling velocity and bed erodibility that describe sediment characteristics, yet these parameters are rarely probed directly. We investigated temporal and spatial variation in sediment parameters in the shallows of San Pablo Bay, CA. Flow, turbulence, and suspended sediment data were measured at sites located at 1 and 2 m below mean lower low water (MLLW) from November 2013 through April 2015, supplemented by monthlong periods in 2011, 2012, and 2016. Maximum current velocities were 0.40–0.47 m s-1 at these depths; the strongest currents decreased to 0.27–0.34 m s-1 during neap periods. Winters 2013–2014 and 2014–2015 experienced strong drought conditions, limiting the potential for seasonal impact on sediment conditions during this experiment. Despite this, the more storm‐influenced site showed clear changes during the winter: the roughness parameter decreased from 10−4 to 10−5 m, from hydrodynamically rough to smooth conditions, and bed erodibility increased by an order of magnitude. Median settling velocity was 2.05·10−4 m s-1; it varied twofold within a tidal cycle, decreasing as current velocity grew during flood and ebb. This tidal control on floc size affected settling velocity on the spring‐neap timescale, possibly driving a spring‐neap oscillation in erodibility. Our findings highlight variation in sediment dynamics that is commonly ignored in numerical models and the need for field observations to ground truth ongoing modeling efforts.
A hybrid sub-lineage of Listeria monocytogenes comprising hypervirulent isolates
Authors: Yin Yuelan , Yao Hao , Doijad Swapnil , Kong Suwei , Shen Yang , Cai Xuexue , Tan Weijun , Wang Yuting , Feng Youwei , Ling Zhiting , Wang Guoliang , Hu Yachen , Lian Kai , Sun Xinyu , Liu Yuliang , Wang Chuanbin , Jiao Kuhua , Liu Guoping , Song Ruilong , Chen Xiang , Pan Zhiming , Loessner Martin J. , Chakraborty Trinad , Jiao Xin’an
Published: September 2019

The foodborne pathogen Listeria monocytogenes (Lm) is a highly heterogeneous species and currently comprises of 4 evolutionarily distinct lineages. Here, we characterize isolates from severe ovine listeriosis outbreaks that represent a hybrid sub-lineage of the major lineage II (HSL-II) and serotype 4h. HSL-II isolates are highly virulent and exhibit higher organ colonization capacities than well-characterized hypervirulent strains of Lm in an orogastric mouse infection model. The isolates harbour both the Lm Pathogenicity Island (LIPI)-1 and a truncated LIPI-2 locus, encoding sphingomyelinase (SmcL), a virulence factor required for invasion and bacterial translocation from the gut, and other non-contiguous chromosomal segments from another pathogenic species, L. ivanovii. HSL-II isolates exhibit a unique wall teichoic acid (WTA) structure essential for resistance to antimicrobial peptides, bacterial invasion and virulence. The discovery of isolates harbouring pan-species virulence genes of the genus Listeria warrants global efforts to identify further hypervirulent lineages of Lm.
A physically cryptographic warhead verification system using neutron induced nuclear resonances
Authors: Engel Ezra M. , Danagoulian Areg
Published: September 2019

Arms control treaties are necessary to reduce the large stockpiles of the nuclear weapons that constitute one of the biggest dangers to the world. However, an impactful treaty hinges on effective inspection exercises to verify the participants’ compliance to the treaty terms. Such procedures would require verification of the authenticity of a warhead undergoing dismantlement. Previously proposed solutions lacked the combination of isotopic sensitivity and information security. Here we present the experimental feasibility proof of a technique that uses neutron induced nuclear resonances and is sensitive to the combination of isotopics and geometry. The information is physically encrypted to prevent the leakage of sensitive information. Our approach can significantly increase the trustworthiness of future arms control treaties while expanding their scope to include the verified dismantlement of nuclear warheads themselves.
Obtaining free USArray data by multi-dimensional seismic reconstruction
Authors: Chen Yangkang , Bai Min , Chen Yunfeng
Published: September 2019

USArray, a pioneering project for the dense acquisition of earthquake data, provides a semi-uniform sampling of the seismic wavefield beneath its footprint and greatly advances the understanding of the structure and dynamics of Earth. Despite continuing efforts in improving the acquisition design, network irregularity still causes spatial sampling alias and incomplete, noisy data, which imposes major challenges in array-based data analysis and seismic imaging. Here we employ an iterative rank-reduction method to simultaneously reconstruct the missing traces and suppress noise, i.e., obtaining free USArray recordings as well as enhancing the existing data. This method exploits the spatial coherency of three-dimensional data and recovers the missing elements via the principal components of the incomplete data. We examine its merits using simulated and real teleseismic earthquake recordings. The reconstructed P wavefield enhances the spatial coherency and accuracy of tomographic travel time measurements, which demonstrates great potential to benefit seismic investigations based on array techniques.
Molecular identification of organic vapors driving atmospheric nanoparticle growth
Authors: Mohr Claudia , Thornton Joel A. , Heitto Arto , Lopez-Hilfiker Felipe D. , Lutz Anna , Riipinen Ilona , Hong Juan , Donahue Neil M. , Hallquist Mattias , Petäjä Tuukka , Kulmala Markku , Yli-Juuti Taina
Published: September 2019

Particles formed in the atmosphere via nucleation provide about half the number of atmospheric cloud condensation nuclei, but in many locations, this process is limited by the growth of the newly formed particles. That growth is often via condensation of organic vapors. Identification of these vapors and their sources is thus fundamental for simulating changes to aerosol-cloud interactions, which are one of the most uncertain aspects of anthropogenic climate forcing. Here we present direct molecular-level observations of a distribution of organic vapors in a forested environment that can explain simultaneously observed atmospheric nanoparticle growth from 3 to 50 nm. Furthermore, the volatility distribution of these vapors is sufficient to explain nanoparticle growth without invoking particle-phase processes. The agreement between observed mass growth, and the growth predicted from the observed mass of condensing vapors in a forested environment thus represents an important step forward in the characterization of atmospheric particle growth.
Destruction of tumor mass by gadolinium-loaded nanoparticles irradiated with monochromatic X-rays: Implications for the Auger therapy
Authors: Matsumoto Kotaro , Saitoh Hiroyuki , Doan Tan Le Hoang , Shiro Ayumi , Nakai Keigo , Komatsu Aoi , Tsujimoto Masahiko , Yasuda Ryo , Kawachi Tetsuya , Tajima Toshiki , Tamanoi Fuyuhiko
Published: September 2019

Synchrotron generated monochromatic X-rays can be precisely tuned to the K-shell energy of high Z materials resulting in the release of the Auger electrons. In this work, we have employed this mechanism to destruct tumor spheroids. We first loaded gadolinium onto the surface of mesoporous silica nanoparticles (MSNs) producing gadolinium-loaded MSN (Gd-MSN). When Gd-MSN was added to the tumor spheroids, we observed efficient uptake and uniform distribution of Gd-MSN. Gd-MSN also can be taken up into cancer cells and localize to a site just outside of the cell nucleus. Exposure of the Gd-MSN containing tumor spheroids to monochromatic X-ray beams resulted in almost complete destruction. Importantly, this effect was observed at an energy level of 50.25 keV, but not with 50.0 keV. These results suggest that it is possible to use precisely tuned monochromatic X-rays to destruct tumor mass loaded with high Z materials, while sparing other cells. Our experiments point to the importance of nanoparticles to facilitate loading of gadolinium to tumor spheroids and to localize at a site close to the nucleus. Because the nanoparticles can target to tumor, our study opens up the possibility of developing a new type of radiation therapy for cancer.
Evaluation of a Recombinant Newcastle Disease Virus Expressing Human IL12 against Human Breast Cancer
Authors: Mohamed Amin Zahiah , Che Ani Muhamad Alhapis , Tan Sheau Wei , Yeap Swee Keong , Alitheen Noorjahan Banu , Syed Najmuddin Syed Umar Faruq , Kalyanasundram Jeevanathan , Chan Soon Choy , Veerakumarasivam Abhi , Chia Suet Lin , Yusoff Khatijah
Published: September 2019

The Newcastle disease virus (NDV) strain AF2240 is an avian avulavirus that has been demonstrated to possess oncolytic activity against cancer cells. However, to illicit a greater anti-cancer immune response, it is believed that the incorporation of immunostimulatory genes such as IL12 into a recombinant NDV backbone will enhance its oncolytic effect. In this study, a newly developed recombinant NDV that expresses IL12 (rAF-IL12) was tested for its safety, stability and cytotoxicity. The stability of rAF-IL12 was maintained when passaged in specific pathogen free (SPF) chicken eggs from passage 1 to passage 10; with an HA titer of 29. Based on the results obtained from the MTT cytotoxic assay, rAF-IL12 was determined to be safe as it only induced cytotoxic effects against normal chicken cell lines and human breast cancer cells while sparing normal cells. Significant tumor growth inhibition (52%) was observed in the rAF-IL12-treated mice. Thein vivosafety profile of rAF-IL12 was confirmed through histological observation and viral load titer assay. The concentration and presence of the expressed IL12 was quantified and verifiedviaELISA assay. In summary, rAF-IL12 was proven to be safe, selectively replicating in chicken and cancer cells and was able to maintain its stability throughout several passages; thus enhancing its potential as an anti-breast cancer vaccine.
Weakly-Emergent Strain-Dependent Properties of High Field Superconductors
Authors: Branch Paul , Tsui Yeekin , Osamura Kozo , Hampshire Damian P.
Published: September 2019

All superconductors in high field magnets operating above 12 T are brittle and subjected to large strains because of the differential thermal contraction between component parts on cool-down and the large Lorentz forces produced in operation. The continuous scientific requirement for higher magnetic fields in superconducting energy-efficient magnets means we must understand and control the high sensitivity of critical current densityJcto strainε. Here we present very detailedJc(B,θ,T,ε) measurements on a high temperature superconductor (HTS), a (Rare−Earth)Ba2Cu3O7−δ(REBCO) coated conductor, and a low temperature superconductor (LTS), a Nb3Sn wire, that include the very widely observed inverted parabolic strain dependence forJc(ε). The canonical explanation for the parabolic strain dependence ofJcin LTS wires attributes it to an angular average of an underlying intrinsic parabolic single crystal response. It assigns optimal superconducting critical parameters to the unstrained state which implies thatJc(ε) should reach its peak value at a single strain (ε = εpeak), independent of fieldB, and temperatureT. However, consistent with a new analysis, the high field measurements reported here provide a clear signature for weakly-emergent behaviour, namelyεpeakis markedlyB, (field angleθfor the HTS) andTdependent in both materials. The strain dependence ofJcin these materials is termed weakly-emergent because it is not qualitatively similar to the strain dependence ofJcof any of their underlying component parts, but is amenable to calculation. We conclude thatJc(ε) is an emergent property in both REBCO and Nb3Sn conductors and that for the LTS Nb3Sn conductor, the emergent behaviour is not consistent with the long-standing canonical explanation forJc(ε).
Comparison of Individual Retinal Layer Thicknesses between Highly Myopic Eyes and Normal Control Eyes Using Retinal Layer Segmentation Analysis
Authors: Kim Jin Hyung , Lee Sung Hoon , Han Jae Yong , Kang Hyun Goo , Byeon Suk Ho , Kim Sung Soo , Koh Hyoung Jun , Lee Sung Chul , Kim Min
Published: September 2019

The incidence of myopia is increasing worldwide, and the investigation on pathophysiology of myopia is becoming more important. This retrospective study aimed to compare the thicknesses of individual retinal layers between high-myopic and control eyes, and to evaluate the effects of age and sex on each retinal layer thickness. We assessed 164 subjects and divided them into two groups based on axial length (AL) (i.e., high-myopic group (AL ≥ 26 mm) and control group (AL < 26 mm)). Individual retinal layer thicknesses of five subfields in the macula were measured using automated retinal segmentation software packaged with the spectral-domain optical coherence tomography and were compared. In high-myopia group, the thicknesses of total retina and all individual retinal layers in central and entire perifoveal subfields were significantly thicker than the corresponding layers in control group after adjustment for ocular magnification (all P < 0.05). There were no significant effects of sex on individual retinal thicknesses, and age had less negative effects on the thicknesses of retina layers in high-myopic eyes than normal eyes. Axially elongated, non-pathologic highly myopic eyes had different structural features than control eyes, with significantly greater individual macular layer thicknesses independent of sex or age.
Ge1−xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration
Authors: Eales Timothy D. , Marko Igor P. , Schulz Stefan , O’Halloran Edmond , Ghetmiri Seyed , Du Wei , Zhou Yiyin , Yu Shui-Qing , Margetis Joe , Tolle John , O’Reilly Eoin P. , Sweeney Stephen J.
Published: October 2019

In this work we study the nature of the band gap in GeSn alloys for use in silicon-based lasers. Special attention is paid to Sn-induced band mixing effects. We demonstrate from both experiment and ab-initio theory that the (direct) Γ-character of the GeSn band gap changes continuously with alloy composition and has significant Γ-character even at low (6%) Sn concentrations. The evolution of the Γ-character is due to Sn-induced conduction band mixing effects, in contrast to the sharp indirect-to-direct band gap transition obtained in conventional alloys such as Al1−xGaxAs. Understanding the band mixing effects is critical not only from a fundamental and basic properties viewpoint but also for designing photonic devices with enhanced capabilities utilizing GeSn and related material systems.
Toward a better understanding of the enhancing/embrittling effects of impurities in Nickel grain boundaries
Authors: Bentria El Tayeb , Lefkaier Ibn Khaldoun , Benghia Ali , Bentria Bachir , Kanoun Mohammed Benali , Goumri-Said Souraya
Published: October 2019

The fracture path follows grain boundaries (GB) in most metallic system under tensile test. In general, impurities, even in ppm concentration, that segregate to these boundaries can remarkably change materials mechanical properties. Predicting impurities segregation effects in Nickel super-alloys might not be seen as intuitive and perhaps more fundamental understanding is needed. We performed a density functional theory calculation to elucidate the effect of eight light elements (B, C, N, O, Al, Si, P and S) and twelve transition metal elements (Tc, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, Ta, W, Re) on Nickel ∑5(210) grain boundary formation and its Ni free surface. The effect of impurities was carefully examined by calculating different properties such as segregation, binding and cohesive energies, strengthening/embrittling potency and the theoretical tensile strength. Additionally, we employed the electron density differences and magnetic effects to explain why and how impurities such as B, S, V, Nb, Mn and W affect Nickel ∑5 GB. We used the generated data calculated on equal footing, to develop a fundamental understanding on impurity effect. A clear and strong correlation is found between difference in magnetic moment change between isolated and imbedded impurity atom on one hand and the tensile strength on the other hand. The higher the loss of the magnetic moment, the more the impurity consolidates the GB.
HCV p7 as a novel vaccine-target inducing multifunctional CD4+ and CD8+ T-cells targeting liver cells expressing the viral antigen
Authors: Filskov Jonathan , Andersen Peter , Agger Else Marie , Bukh Jens
Published: October 2019

Despite recent treatment advances for chronic hepatitis C virus (HCV) infection, a vaccine is urgently needed for global control of this important liver pathogen. The lack of robust immunocompetent HCV infection models makes it challenging to identify correlates of protection and test vaccine efficacy. However, vigorous CD4+and CD8+T-cell responses are detected in patients that spontaneously resolve acute infection, whereas dysfunctional T-cell responses are a hallmark of chronic infection. The HCV p7 protein, forming ion-channels essential for viral assembly and release, has not previously been pursued as a vaccine antigen. Herein, we demonstrated that HCV p7 derived from genotype 1a and 1b sequences are highly immunogenic in mice when employed as overlapping peptides formulated as nanoparticles with the cross-priming adjuvant, CAF09. This approach induced multifunctional cytokine producing CD4+and CD8+T-cells targeting regions of p7 that are subject to immune pressure during HCV infection in chimpanzees and humans. Employing a surrogatein vivochallenge model of liver cells co-expressing HCV-p7 and GFP, we found that vaccinated mice cleared transgene expressing cells. This study affirms the potential of a T-cell inducing nanoparticle vaccine platform to target the liver and introduces HCV p7 as a potential target for HCV vaccine explorations.
Synthesis and characterization of Mono-disperse Carbon Quantum Dots from Fennel Seeds: Photoluminescence analysis using Machine Learning
Authors: Dager Akansha , Uchida Takashi , Maekawa Toru , Tachibana Masaru
Published: September 2019

Herein, we present the synthesis of mono-dispersed C-QDs via single-step thermal decomposition process using the fennel seeds (Foeniculum vulgare). As synthesized C-QDs have excellent colloidal, photo-stability, environmental stability (pH) and do not require any additional surface passivation step to improve the fluorescence. The C-QDs show excellent PL activity and excitation-independent emission. Synthesis of excitation-independent C-QDs, to the best of our knowledge, using natural carbon source via pyrolysis process has never been achieved before. The effect of reaction time and temperature on pyrolysis provides insight into the synthesis of C-QDs. We used Machine-learning techniques (ML) such as PCA, MCR-ALS, and NMF-ARD-SO in order to provide a plausible explanation for the origin of the PL mechanism of as-synthesized C-QDs. ML techniques are capable of handling and analyzing the large PL data-set, and institutively recommend the best excitation wavelength for PL analysis. Mono-disperse C-QDs are highly desirable and have a range of potential applications in bio-sensing, cellular imaging, LED, solar cell, supercapacitor, printing, and sensors.
Enhanced relativistic-electron beam collimation using two consecutive laser pulses
Authors: Malko Sophia , Vaisseau Xavier , Perez Frederic , Batani Dimitri , Curcio Alessandro , Ehret Michael , Honrubia Javier , Jakubowska Katarzyna , Morace Alessio , Santos João Jorge , Volpe Luca
Published: October 2019

The double laser pulse approach to relativistic electron beam (REB) collimation in solid targets has been investigated at the LULI-ELFIE facility. In this scheme two collinear laser pulses are focused onto a solid target with a given intensity ratio and time delay to generate REBs. The magnetic field generated by the first laser-driven REB is used to guide the REB generated by a second delayed laser pulse. We show how electron beam collimation can be controlled by properly adjusting the ratio of focus size and the delay time between the two pulses. We found that the maximum of electron beam collimation is clearly dependent on the laser focal spot size ratio and related to the magnetic field dynamics. Cu-Kα and CTR imaging diagnostics were implemented to evaluate the collimation effects on the respectively low energy (≤100 keV) and high energy (≥MeV) components of the REB.