bluuebunny/crossref_metadata_2025 huggingface dataset:
Generating realistic IoT‐based IDS dataset centred on fuzzy qualitative modelling for cyber‐physical systems
Authors: Ahmed Khan Izhar , Pi Dechang , Bhatia Ajeet Kumar , Khan Nasrullah , Haider Waqas , Wahab Abdul
Published: February 2020

Before using any dataset in the intrusion detection system (IDS), it is crucial to acquire an accurate assessment of its efficiency. Nevertheless, the key complications presently met by the researchers are the deficiency of accessibility of any genuine assessment dataset and efficient metric for evaluating the enumerated quality of realism (QoR) of any internet of things (IoT)‐based IDS dataset. It is challenging to obtain and gather data from real‐world company setups owing to commercial continuousness and concerns such as integrity. This Letter presents a Sugeno fuzzy inference machine (SFIM)‐based metric method for assessing the QoR of existing IoT IDS datasets. Secondly, based on the results of the proposed metric, a synthetically precise next level IoT‐based IDS dataset is aimed and produced, and an initial assessment showed to support the development of forthcoming IoT‐IDS. This created dataset comprises both regular and irregular replications of present IoT‐based network events happening at the precarious cyber structure in different companies. Finally, the QoR of the generated dataset is evaluated by means of the proposed metric and is compared with state‐of‐the‐art commonly available compelling datasets for validating its supremacy.
Study on a Marx generator with high‐voltage silicon‐stacks instead of isolating inductances
Authors: Chen Rong , Yang Jianhua , Cheng Xinbing , Qian Baoliang
Published: February 2020

Marx generator is a voltage boosting device for power pulse compression, in which its capacitors are charged in parallel and discharged in series. To get a higher voltage boost ratio, high‐voltage silicon stacks have been applied to substitute the isolated inductances in this study. Experiments with two isolation modes in the Marx generator have been carried out. Experimental results reveal that the high‐voltage silicon stacks with the parameters of 50 kV/1 kA used in the Marx generator can increase the voltage step‐up ratio to 168.6:1, up from 141:1 and 162.9:1 when isolating inductances and silicon‐stacks with parameters of 50 kV/3 kA are applied, respectively. Moreover, the silicon stack‐isolating‐type Marx generator can almost eliminate the pre‐pulse existing on the load if the isolated inductances employed. Therefore, it is crucial to choose appropriate high‐voltage silicon stacks as the isolating devices in the Marx generator designed in this study.
Frequency response of energy storage systems in grids with high level of wind power penetration – Gotland case study
Authors: Daraiseh Firas
Published: February 2020

Gotland is a Swedish island that is connected to the grid only by two high voltage direct current (HVDC) cables. The growth of installed wind power on Gotland has been temporarily stopped due to concerns regarding the reliability of the operations. This study investigates the capability of a centralised energy storage system along with or without wind curtailment to support the growth of installed wind power capacity. The energy storage system is tested for maintaining frequency stability during unintentional islanding through dynamic studies using power system simulator for engineering (PSS/E). The results assess the ability of energy storage to prevent frequency instabilities and provide primary frequency response albeit of the absence of any rotating inertia. The analysis determines the requirements for the power and energy capacity of the energy storage system in relation to the exported power from the HVDC cables at the instant of fault, which eventually relates to the wind power capacity. Moreover, the study examines wind power curtailment as primary and/or secondary frequency response and the impact on the energy capacity. Finally, the study did not explore the effect of fast power ramps on the energy storage to leave the door open for all types of inverter‐based energy storage technologies.
Real‐time stability assessment in smart cyber‐physical grids: a deep learning approach
Authors: Darbandi Farzad , Jafari Amirreza , Karimipour Hadis , Dehghantanha Ali , Derakhshan Farnaz , Raymond Choo Kim‐Kwang
Published: February 2020

The increasing coupling between the physical and communication layers in the cyber‐physical system (CPS) brings up new challenges in system monitoring and control. Smart power grids with the integration of information and communication technologies are one of the most important types of CPS. Proper monitoring and control of the smart grid are highly dependent on the transient stability assessment (TSA). Effective TSA can provide system operators with insightful information on stability statuses and causes under various contingencies and cyber‐attacks. In this study, a real‐time stability condition predictor based on a feedforward neural network is proposed. The conjugate gradient backpropagation algorithm and Fletcher–Reeves updates are used for training, and the Kohonen learning algorithm is utilised to improve the learning process. By real‐time assessment of the network features based on the minimum redundancy maximum relevancy algorithm, the proposed method can successfully predict transient stability and out of step conditions for the network and generators, respectively. Simulation results on the IEEE 39‐bus test system indicate the superiority of the proposed method in terms of accuracy, precision, false positive rate, and true positive rate.
Le dialogue entre les cellules souches intestinales et les lymphocytes T CD4+ module l’homéostasie des cellules souches
Authors: Thevin Valentin , Soudja Saidi
Published: February 2020

Dans le cadre d’un partenariat avec médecine/sciences, et pour la troisième année, des étudiants du module d’immunologie virologie et cancer du Master de cancérologie de Lyon présentent une analyse d’articles scientifiques récents faisant état d’observations innovantes et importantes. Ce travail a été encadré par des chercheurs confirmés du département d’immunologie, virologie et inflammation du CRCL. Le master de cancérologie de Lyon (Lyon1-VetAgroSup) accueille chaque année 30 à 40 étudiants en M1 et en M2. Ce master dit « d’excellence » assure aux étudiants de M1 une formation à la cancérologie reposant sur un socle de base commun (biologie cellulaire, moléculaire, immunologie, bio-statistique...). En M2, les étudiants peuvent choisir l’une des trois spécialités suivantes : le Master recherche « Recherche en cancérologie », le Master recherche et professionnel « Technologie haut débit en cancérologie » et enfin le Master recherche et professionnel « Innovations thérapeutiques en cancérologie ». Le Master de cancérologie de Lyon repose sur une forte implication des chercheurs et enseignants-chercheurs du laboratoire d’excellence en développement et cancérologie (LabEx DEVweCAN), ainsi que sur un partenariat solide avec plusieurs instituts dont le MIT (Massachusetts Institute of Technology, Cambridge, États-Unis), l’université d’Harvard (Boston, États-Unis), l’université Johns Hopkins (Baltimore, États-Unis), l’Imperial College of London (Royaume-Uni), les universités de Jiao Tong (République Populaire de Chine) et de Tokyo (Japon), entre autres. Pour plus d’information : http://devwecan.universite-lyon.fr/formation/
Update Myokarditis
Authors: Könemann Stephanie , Beug Daniel , Dörr Marcus , Felix Stephan B.
Published: February 2020

Was ist neu?

Diagnostisches Vorgehen Im Rahmen einer standardisierten Vorgehensweise kann die nichtinvasive kardiale Diagnostik erste Hinweise für das Vorliegen einer Myokarditis liefern, bevor mittels Myokardbiopsie anhand histologischer und immunhistochemischer Kriterien die Sicherung der Diagnose erfolgt. Bei Verdacht auf eine Myokarditis sollte zudem eine Magnetresonanztomografie (MRT) durchgeführt werden, die mit hoher diagnostischer Güte den Nachweis einer Entzündung und eines Ödems als spezifische Myokarditis-Befunde ermöglicht und Aufschluss über die regionale Verteilung und Ausprägung der pathologischen Veränderungen gibt.

Geschlechtsspezifische Unterschiede bei der Myokarditis Bei Frauen sollte auch bei nur geringem Hinweis auf eine Myokarditis eine diagnostische Standardroutine erfolgen. Krankheitssymptome sowie die Erhöhung der Kreatinkinase und des Myoglobins sind bei ihnen weniger stark ausgeprägt als bei Männern.

Therapie Die Grundlage der Myokarditis-Therapie bildet die leitliniengerechte Behandlung der Symptome, einer eventuell bestehenden Herzinsuffizienz sowie, bei hämodynamischer Instabilität, eine intensivmedizinische Behandlung. Für den Nutzen spezifischer immunmodulatorischer oder immunsuppressiver Therapieansätze gibt es, mit Ausnahme der seltenen Riesenzellmyokarditis, derzeit noch keine gesicherten klinischen Daten.
Das kleine Einmaleins tiergestützter Therapie – Ergotherapie mit Hund
Authors: Junkers Anja
Published: February 2020

Hunde gelten in vielen Fachbereichen als geeignete Therapiebegleiter. Sie können Klienten dabei helfen, ihre Ziele schneller und effektiver zu erreichen. Anja Junkers beschreibt, warum das so ist und auf welche Weise die Tiere bei betätigungszentrierten Interventionen zum Einsatz kommen.
Die Rechtsfrage: Was tun, wenn der Patient die Rechnung nicht bezahlt? – Die Antwort unseres Experten
Authors: Bossow Karsten
Published: February 2020

„Patienten, die ihre Rechnungen nicht bezahlen, erhalten von uns eine Mahnung per Post. Trotzdem bleiben die Zahlungen manchmal aus. Wie können wir sicherstellen, dass der Patient die Mahnung erhält und wir im Streitfall an unser Geld kommen?“

Therapieteam aus Stuttgart
Der richtige Mensch am falschen Platz – Stellen optimal besetzen
Authors: Freitag-Herse Barbara
Published: February 2020

Bei der Besetzung einer Schlüsselstelle ist Fingerspitzengefühl gefragt. Doch auch, wenn die Entscheidung für ein bestimmtes Teammitglied anfangs manchmal noch so gut und richtig erscheint, kann sie sich als Fehlbesetzung entpuppen. Dann sollten Sie handeln, und zwar schnell.
Erinnerungen zum Leben erwecken – Autobiografische Erinnerung als Lernmittel in der Neurokognitiven Rehabilitation nach Perfetti
Authors: Wopfner Susanne
Published: February 2020

Bei der autobiografischen Erinnerung denken Patienten, die Bewegungsabläufe verbessern möchten, an eine emotionale Situation vor der Erkrankung, bei der sie zum Beispiel ein Gefühl von Leichtigkeit empfunden haben. In Verbindung mit der Neurokognitiven Rehabilitation fällt es ihnen damit leichter, auch im Alltag Handlungen physiologisch auszuführen.
ABCA4-Associated Stargardt Disease
Authors: Khan Mubeen , Cremers Frans P.M.
Published: February 2020

Autosomal recessive Stargardt disease (STGD1) is associated with variants in the ABCA4 gene. The phenotypes range from early-onset STGD1, that clinically resembles severe cone-rod dystrophy, to intermediate STGD1 and late-onset STGD1. These different phenotypes can be correlated with different combinations of ABCA4 variants which can be classified according to their degree of severity. A significant fraction of STGD1 cases, particularly late-onset STGD1 cases, were shown to carry only a single ABCA4 variant. A frequent coding variant (p.Asn1868Ile) was recently identified which – in combination with a severe ABCA4 variant – is generally associated with late-onset STGD1. In addition, an increasing number of rare deep-intronic variants have been found and some of these are also associated with late-onset STGD1. The effect of these and other variants on ABCA4 RNA was tested using in vitro assays in human kidney cells using specially designed midigenes. With stem cells and photoreceptor progenitor cells derived from patient skin or blood cells, retina-specific splice defects can be assessed. With expert clinical examination to distinguish STGD1 cases from other maculopathies, as well as in-depth genomics and transcriptomics data, it is now possible to identify both mutant ABCA4 alleles in > 95% of cases.
Eindellende Operationen zur Behandlung der rhegmatogenen Amotio in Deutschland: ein Geist der Vergangenheit oder gelebte Praxis?
Authors: Bucher Felicitas , Daniel Moritz Claudius , Böhringer Daniel , Lange Clemens , Reinhard Thomas , Agostini Hansjürgen , Lang Stefan J.
Published: February 2020

Hintergrund und Fragestellung Eindellende Operationen und Vitrektomien stellen Behandlungsoptionen bei Netzhautablösungen dar. Vergleichende Studien räumen eindellenden Operationen, umgangssprachlich auch als Buckelchirurgie bezeichnet, besonders bei der Versorgung phaker Patienten einen wichtigen Stellenwert ein. Dennoch wird postuliert, dass die Häufigkeit eindellender Eingriffe deutlich abnehme. Ziel dieser Arbeit ist es, die Häufigkeit eindellender Eingriffe zur Behandlung von Netzhautablösungen in Deutschland über die Zeit darzustellen.

Material und Methoden Die Anzahl eindellender Operationen (OPS 5-152) und rhegmatogener Netzhautablösungen (ICD H33.0) in Deutschland zwischen 2006 und 2017 werden auf Datenbasis der Qualitätsberichte der Krankenhäuser sowie der fallpauschalenbezogenen Krankenhausstatistik (DRG-Statistik, German Diagnosis Related Groups) des Statistischen Bundesamts ermittelt.

Ergebnisse Laut Krankenhausqualitätsberichten fiel die Anzahl eindellender Eingriffe im Zeitraum von 2006 bis 2017 um 49% von 8841 auf 4510. Im selben Zeitraum stieg die Anzahl der unter H33.0 codierten Netzhautablösungen um 102% von 11 507 auf 23 314. Die deutlich abnehmende Zahl eindellender Eingriffe bei Amotio retinae bestätigte sich in der Analyse der DRG-Statistik, welche ebenfalls deren Abfall um 42% zeigte. Eine Aufschlüsselung der Daten nach Bundesländern und Patientenalter weist regionale wie auch altersabhängige Unterschiede in der Anwendungshäufigkeit eindellender Eingriffe auf.

Diskussion Die Daten zeigen eindrücklich, dass eindellende Operationen in Deutschland deutlich seltener durchgeführt werden als noch im Jahr 2006. Dennoch stellt die Buckelchirurgie mit ca. 4500 codierten Eingriffen im Jahr 2017 weiterhin eine wichtige und praktizierte Säule bei der Versorgung von Patienten mit Netzhautablösungen dar.
Inanspruchnahme der multidisziplinären spezialisierten Fallkonferenz im Freiburger Orbitazentrum
Authors: Lang Stefan J. , Joachimsen Lutz , Stifter Julia , Reich Michael , Küchlin Sebastian , Böhringer Daniel , Metzger Marc , Lagrèze Wolf Alexander
Published: February 2020

Hintergrund Die Behandlung von Tumorerkrankungen erfolgt zunehmend in interdisziplinären Zentren. Therapieentscheidungen werden dabei häufig im Rahmen von Fallkonferenzen getroffen. Erkrankungen der Orbita betreffen mehrere Disziplinen. Neben Augenärzten sind in erster Linie Mund-, Kiefer- und Gesichtschirurgen, HNO-Ärzte, Neurochirurgen, aber auch Pädiater, Strahlentherapeuten und Radiologen beteiligt. Ziel unserer Arbeit ist die Vorstellung einer multidisziplinären Fallkonferenz für Orbitaerkrankungen. Dargestellt werden die bisherige Inanspruchnahme, die Indikationen und die Therapieentscheidungen.

Methoden Wir analysierten alle Patienten, welche von 2008 bis 2018 in der Fallkonferenz des Orbitazentrums des Universitätsklinikums Freiburg vorgestellt wurden, im Hinblick auf klinische Diagnose, histologische Diagnosen, Anzahl der operativen Eingriffe sowie Rate der interdisziplinären Therapieentscheidungen. Der Datensatz wurde vor Analyse vollständig anonymisiert.

Ergebnisse Von 2008 bis 2018 wurden 545 Fälle in die wöchentliche Fallkonferenz eingebracht. Davon lagen 453 anonymisiert zur Auswertung vor. Das mediane Alter bei Vorstellung betrug  56 Jahre (Quartile 41; 69). Die häufigste Indikation war ein Orbitatumor unklarer Dignität (n = 52; 11%). Weitere Indikationen waren endokrine Orbitopathie (n = 39; 9%), Pseudotumor orbitae (n = 36; 8%), eine Augenmuskelparese (n = 22; 5%) oder ein Lymphom der Orbita (n = 22; 5%). Die häufigsten histologischen Diagnosen waren B-Zell-Lymphome (n = 10; 2%), kavernöses Hämangiom (n = 8; 2%), Marginalzonenlymphome (n = 8; 2%) und Plattenepithelkarzinome (n = 6; 1%). Bei 174 Patienten wurde ein konkretes Vorgehen interdisziplinär festgelegt.

Schlussfolgerungen Es zeigt sich eine hohe Inanspruchnahme der Fallkonferenz Orbitazentrum am Universitätsklinikum Freiburg. Die hohe Anzahl an interdisziplinären Entscheidungen untermauert die Notwendigkeit einer solchen Konferenz. Den Patienten bleiben so mehrfache Untersuchungen in den einzelnen Fachabteilungen erspart und es können schnelle und effektive interdisziplinäre Therapieentscheidungen getroffen werden.
A Large, Severely Obstructive, Calcified Mass in the Midsegment of Aortic Arch
Authors: Patel Brijesh , Shah Mahek , Vyas Apurva , Misselbeck Timothy , Burke James A.
Published: February 2020

Severe obstructive lesions in the aortic arch are rare. Crossing such lesions poses additional challenges in patients who require cardiac catheterizations. Oftentimes, specialized catheters are required to negotiate the lesion. Herein, we are reporting a series of case images that illustrate a severe lesion in the aortic arch during coronary angiography.
Quadratic response of random and deterministic dynamical systems
Authors: Galatolo Stefano , Sedro Julien
Published: February 2020

We consider the linear and quadratic higher-order terms associated with the response of the statistical properties of a dynamical system to suitable small perturbations. These terms are related to the first and second derivative of the stationary measure with respect to the changes in the system itself, expressing how the statistical properties of the system vary under the perturbation. We show a general framework in which one can obtain rigorous convergence and formulas for these two terms. The framework is flexible enough to be applied both to deterministic and random systems. We give examples of such an application computing linear and quadratic response for Arnold maps with additive noise and deterministic expanding maps.
Calibration of polyvinylidene fluoride based dust detectors in response to varying grain density and incidence angle
Authors: Piquette M. , James D. , Horányi M.
Published: February 2020

Permanently polarized Polyvinylidene Fluoride (PVDF) films have been used on a variety of spacecraft as in situ dust detectors to measure the size and spatial distributions of micron and sub-micron dust particles. The detectors produce a short electric pulse when impacted by a hypervelocity dust particle. The pulse amplitude depends on the mass and relative speed of the dust grain. This relationship has been studied both empirically and numerically to better understand the film’s principle of operation, as well as the effects of film thickness, film temperature, and particle penetration depth. However, little work has been done to constrain the effects of varying particle density and incidence angle despite the frequent occurrence of such configurations in most space-based applications. We present calibrations of non-penetrating impacts on 28 μm thick films at varying incidence angles ranging from 0° to 75° for iron and aluminum particles in the mass and speed range of 10−12 ≤ m ≤ 10−8 g and 0.5 ≤ v ≤ 7 km/s, respectively. The study was carried out at the 3 MV dust accelerator laboratory at the University of Colorado at Boulder. The results show that PVDF signals are largely independent of particle density and incidence angle up to 75° for non-penetrating impacts.
Kinetic flux ropes: Bernstein–Greene–Kruskal modes for the Vlasov–Poisson–Ampère system
Authors: Ng C. S.
Published: February 2020

Electrostatic structures have been observed in many regions of space plasmas, including the solar wind, the magnetosphere, and the auroral acceleration region. One possible theoretical description of some of these structures is the concept of Bernstein–Greene–Kruskal (BGK) modes, which are exact nonlinear steady-state solutions of the Vlasov–Poisson system of equations in collisionless kinetic theory. We generalize the exact solutions of two-dimensional BGK modes in a magnetized plasma with a finite magnetic field strength [Ng et al., Phys. Plasmas 13, 055903 (2006)] to cases with azimuthal magnetic fields so that these structures carry the electric current as well as the steady electric and magnetic fields. Such nonlinear solutions now exactly satisfy the Vlasov–Poisson–Ampère system of equations. Explicit examples with either positive or negative electric potential structure are provided.
Neutron generator based on intense lithium beam driver
Authors: Ikeda Shunsuke , Okamura Masahiro , Kanesue Takeshi , Raparia Deepak , Hershcovitch Ady , Yip Kin , Takahashi Kazumasa , Wu Dong , Cannavò Antonino , Ceccio Giovanni
Published: February 2020

We are proposing a compact neutron generator based on a Li beam driver. The proposed neutron generator comprises a laser ion source, a radio-frequency quadrupole linear accelerator (RFQ linac), a drift tube linac, and a target containing protons. In the generator, the lithium ion is used as a projectile instead of protons to utilize the kinematic focusing technique. The technique enables us to enhance the neutron flux without increasing the beam energy, which is important to develop a clean compact neutron generator. Moreover, the combination of a laser ion source and a RFQ linac with the direct plasma injection scheme will provide several tens of mA of a fully ionized lithium beam, which is much higher than that of conventional heavy ion sources comparable with proton drivers. Neutrons are generated by the nuclear reaction of the lithium ions and protons in the beam target. In this paper, we reported the current status of the development. For RFQ, we designed the RFQ rods to accelerate 40 mA of 7Li3+. We fabricated and installed the rods into a cavity, and, as a first test, accelerated 10 mA of C6+ successfully.
Laser oscillation at an intended wavelength from a distributed feedback structure on anisotropic organic crystals
Authors: Inada Yuhi , Kawata Yoshihiro , Kawai Tatsunori , Hotta Shu , Yamao Takeshi
Published: February 2020

An organic laser device is constructed as distributed feedback (DFB) type using an anisotropic single crystal of an organic semiconductor oligomer BP3T. The DFB structure is formed on top of the crystal via an interference exposure technique of a positive type photoresist. In the DFB structure, both the phase matching condition and waveguide condition must be fulfilled. Under these conditions, the effective refractive indices can be precisely predicted for a BP3T crystal, and they vary depending upon the crystal thickness. As a result, the device produces a single-mode laser oscillation at an intended wavelength (typically ∼569 nm). The present study enables us to design a down-to-earth laser device based on an anisotropic organic semiconductor crystal toward practical use.
Enhanced optical emission in laser-induced breakdown spectroscopy by combining femtosecond and nanosecond laser pulses
Authors: Wang Ying , Chen Anmin , Zhang Dan , Wang Qiuyun , Li Suyu , Jiang Yuanfei , Jin Mingxing
Published: February 2020

The role of inter-pulse delay time in laser-induced Cu plasma with femtosecond and nanosecond double-pulse irradiation had been investigated by optical emission spectroscopy. The experimental results showed that a significant enhancement effect in the atomic line emission was observed by changing the inter-pulse delay time. The spectral intensity of Cu plasma produced by a femtosecond + nanosecond double-pulse was higher than that produced by a nanosecond + femtosecond dual-pulse. That is to say, the shorter laser pulse (femtosecond) was efficient in coupling to the sample and the longer laser pulse (nanosecond) was suitable for re-exciting the produced plasma. In addition, the corresponding plasma temperature and electron density were also calculated. The plasma temperature in the case of femtosecond + nanosecond was lower than that in the case of nanosecond + femtosecond, while the electron density in the case of femtosecond + nanosecond was higher than that in the case of nanosecond + femtosecond. This study is helpful for the research on sample detection using femtosecond and nanosecond double-pulse laser-induced breakdown spectroscopy.
Ultra-compact visible light depolarizer based on dielectric metasurface
Authors: Wang Yilin , Zhu Wenqi , Zhang Cheng , Fan Qingbin , Chen Lu , Lezec Henri , Agrawal Amit , Xu Ting
Published: February 2020

With rapid development toward shrinking the size of traditional photonic systems such as cameras, spectrometers, displays, and illumination systems, there is an urgent need for high-performance and ultra-compact functional optical elements. Metasurfaces, consisting of an array of subwavelength nanoscatterers with spatially varying geometries, have shown remarkable performance as ultrathin multifunctional optical elements. Here, based on an all-dielectric metasurface, we propose and experimentally demonstrate a spatial domain optical depolarizer capable of efficiently depolarizing linearly polarized light in the visible spectral band from 450 nm to 670 nm, with a degree of polarization of less than 10%. Remarkably, it is capable of depolarizing the light beam with a diameter down to several micrometers, about two orders of magnitude smaller than commercial liquid-crystal-based depolarizers. We envision the metasurface depolarizer to find its applications in the next generation ultra-compact grating spectrometers and illumination systems.
Defect distribution in boron doped silicon nanostructures characterized by means of scanning spreading resistance microscopy
Authors: Prüßing Jan K. , Böckendorf Tim , Hamdana Gerry , Peiner Erwin , Bracht Hartmut
Published: February 2020

Scanning spreading resistance microscopy (SSRM) was applied on boron (B) doped bulk and nanostructured silicon (Si) samples. Finite element simulations are performed to calculate the expected resistance profile based on secondary ion mass spectrometry data of the chemical B profile. Differences between experimental and simulated resistance scans are consistently described by the interaction of electrically active dopants with defect states. These states are strongly correlated to the cross-sectional sample preparation applied before the SSRM analysis. Whereas the B-doped bulk sample only reveals preparation induced bulk and surface defects, the SSRM scan of B-doped Si pillars is additionally affected by interface defects at the outer shell of the pillar. These interface defects do not only affect the concentration of charged carriers in the Si pillar but could also influence dopant diffusion in nanostructured Si.
Polyacrylate grafted graphene oxide nanocomposites for biomedical applications
Authors: Ganya Elison S. , Soin Navneet , Moloi Sabata J. , McLaughlin James A. , Pong W. F. , Ray Sekhar C.
Published: February 2020

Utilizing a reverse micelle process, we have grafted polyacrylate (P) on graphene oxide (GO) to realize polyacrylate grafted graphene oxide (P-GO) nanocomposites, upon whose subsequent reduction, polyacrylate grafted reduced graphene oxide (P-rGO) nanocomposites are achieved. Using techniques such as ultraviolet photoelectron spectroscopy (UPS), x-ray photoelectron spectroscopy, and x-ray absorption near edge structure (XANES) spectroscopy, in conjunction with high-resolution microscopy, Raman spectroscopy, and superconducting quantum interference device analysis, we have studied in depth the electronic, microstructural, electrical, and magnetic properties of these P-GO and P-rGO nanocomposites. While polyacrylate grafting ensures a high solubility of P-GO and P-rGO, the P-rGO nanocomposites additionally show a near doubling of the paramagnetic response (9.6 × 10−3 emu/g) as compared to the r-GO (5.6 × 10−3 emu/g) and P-GO (5.5 × 10−3 emu/g), respectively, at 2 K. The grafting of diamagnetic polyacrylate enhances the magnetic response for the P-GO and P-rGO owing to the increase in the defect states, sp3-type bonding, and enhanced magnetic coupling between the magnetic moments arising due to the presence of nitrogen functionalities. This behavior is further corroborated via the measurements of the electronic structure by XANES and UPS measurements. Thus, the possibility of manipulation of the magnetic behavior along with the abundance of surface functional groups makes both P-GO and P-rGO nanocomposites highly conducive for deriving water-soluble functionalized graphene by linking affinity molecules with polyacrylate backbone for biological and biomedical applications.
Partial oxidation of methane to methanol by isolated Pt catalyst supported on a CeO2 nanoparticle
Authors: Kye So-Hwang , Park Hee Sun , Zhang Renqin , Yang Hee Jung , Lee Kyu Hyung , Suh Hoyoung , Kim Jin-Gyu , Kim Min Gyu , Hwang Gyeong S. , Hur Nam Hwi
Published: February 2020

Catalytic transformation of methane (CH4) into methanol in a single step is a challenging issue for the utilization of CH4. We present a direct method for converting CH4 into methanol with high selectivity over a Pt/CeO2 catalyst which contains ionic Pt2+ species supported on a CeO2 nanoparticle. The Pt/CeO2 catalyst reproducibly yielded 6.27 mmol/g of Pt with a selectivity of over 95% at 300 °C when CH4 and CO are used as reactants, while the catalyst had a lower activity when using only CH4 without CO. Active lattice oxygen created on the Pt and CeO2 interface provides selective reaction pathways for the conversion of CH4 to methanol. Based on high-angle annular dark-field scanning transmission electron microscopy, x-ray photoelectron spectroscopy, x-ray absorption near-edge structure, extended x-ray absorption fine structure, catalytic studies, and density functional theory calculations, we propose a mechanistic pathway involving CH4 activation at the active site in the vicinity of Pt2+ species.
Evolution of 0.7 conductance anomaly in electric field driven ferromagnetic CuO junction based resistive random access memory devices
Authors: Banerjee Writam , Hwang Hyunsang
Published: February 2020

This study demonstrates the origin of 0.7 conductance anomaly and non-volatile reversible control of switching in atomically controlled resistive random access memory devices. In quantum devices, 0.7 structure and zero bias anomaly (ZBA) are considered as the natural presence of spin state. Here, we show that similar behavior can be detected in an atomically thin electrically controllable break junction based on Cu/Ti/HfO2/TiN resistive switches in which the origin of the 0.7 structure is statistically controlled by the device design, filament geometry, and optimized electrical measurement scheme. Evidence of temperature dependent evolution of 0.7 plateau and low temperature ZBA is presented here. Lorentzians of the experimental result indicate the formation of a ZBA and non-ZBA like state at a low resistance state and a high resistance state of the resistive switches. Repeated spin-like switching is achieved by controlling the chemical composition of the filament in the sub-quantum region by the electric field driven ion redistribution process. During switching, formation of a ferromagnetic CuO atom in the break junction surrounded by Cu electron sources, i.e., nanoionics, manifests the suitable environment for spin-like behavior.
Rotational-permutational dual-pairing and long-lived spin order
Authors: Bengs C.
Published: February 2020

Quantum systems in contact with a thermal environment experience coherent and incoherent dynamics. These drive the system back toward thermal equilibrium after an initial perturbation. The relaxation process involves the reorganization of spin state populations and the decay of spin state coherences. In general, individual populations and coherences may exhibit different relaxation time constants. Particular spin configurations may exhibit exceptionally long relaxation time constants. Such spin configurations are known as long-lived spin order. The existence of long-lived spin order is a direct consequence of the symmetries of the system. For nuclear spin systems, rotational and permutational symmetries are of fundamental importance. Based on the Schur–Weyl duality theorem, we describe a theoretical framework for the study of rotational and permutational dual-symmetries in the context of long-lived spin order. Making use of the proposed formalism, we derive refined bounds on the number on long-lived spin populations and coherences for systems exhibiting rotational-permutational dual-symmetries.
Synonymous codon substitutions perturb cotranslational protein folding in vivo and impair cell fitness
Authors: Walsh Ian M. , Bowman Micayla A. , Soto Santarriaga Iker F. , Rodriguez Anabel , Clark Patricia L.
Published: February 2020

In the cell, proteins are synthesized from N to C terminus and begin to fold during translation. Cotranslational folding mechanisms are therefore linked to elongation rate, which varies as a function of synonymous codon usage. However, synonymous codon substitutions can affect many distinct cellular processes, which has complicated attempts to deconvolve the extent to which synonymous codon usage can promote or frustrate proper protein folding in vivo. Although previous studies have shown that some synonymous changes can lead to different final structures, other substitutions will likely be more subtle, perturbing predominantly the protein folding pathway without radically altering the final structure. Here we show that synonymous codon substitutions encoding a single essential enzyme lead to dramatically slower cell growth. These mutations do not prevent active enzyme formation; instead, they predominantly alter the protein folding mechanism, leading to enhanced degradation in vivo. These results support a model in which synonymous codon substitutions can impair cell fitness by significantly perturbing cotranslational protein folding mechanisms, despite the chaperoning provided by the cellular protein homeostasis network.
Control of XPR1-dependent cellular phosphate efflux by InsP
8
is an exemplar for functionally-exclusive inositol pyrophosphate signaling
Authors: Li Xingyao , Gu Chunfang , Hostachy Sarah , Sahu Soumyadip , Wittwer Christopher , Jessen Henning J. , Fiedler Dorothea , Wang Huanchen , Shears Stephen B.
Published: February 2020

Significance

Biological roles of inorganic phosphate require careful regulation of its transport across cell membranes, but mechanisms are poorly understood. We demonstrate that a major cellular phosphate export protein, XPR1, is regulated by the most “energetic” of cell signaling molecules—1,5-bisdiphosphoinositol 1,2,3,4-tetrakisphosphate (InsP
8
). We derive this conclusion by showing reduced XPR1-mediated phosphate efflux when InsP
8
synthesis was attenuated by genetic or pharmacological techniques; phosphate efflux was rescued by using liposomes to deliver into cells metabolically resistant InsP
8
analogues. Genetic elimination of InsP
8
from an osteosarcoma cell line perturbed phosphate homeostasis and accelerated differentiation into a biomineralization phenotype. We propose that mutations in gene products that regulate InsP
8
synthesis might compromise
XPR1
function, with pathological consequences for bone maintenance and ectopic calcification.
Hsp47 promotes cancer metastasis by enhancing collagen-dependent cancer cell-platelet interaction
Authors: Xiong Gaofeng , Chen Jie , Zhang Guoying , Wang Shike , Kawasaki Kunito , Zhu Jieqing , Zhang Yan , Nagata Kazuhiro , Li Zhenyu , Zhou Binhua P. , Xu Ren
Published: February 2020

Increased expression of extracellular matrix (ECM) proteins in circulating tumor cells (CTCs) suggests potential function of cancer cell-produced ECM in initiation of cancer cell colonization. Here, we showed that collagen and heat shock protein 47 (Hsp47), a chaperone facilitating collagen secretion and deposition, were highly expressed during the epithelial-mesenchymal transition (EMT) and in CTCs. Hsp47 expression induced mesenchymal phenotypes in mammary epithelial cells (MECs), enhanced platelet recruitment, and promoted lung retention and colonization of cancer cells. Platelet depletion in vivo abolished Hsp47-induced cancer cell retention in the lung, suggesting that Hsp47 promotes cancer cell colonization by enhancing cancer cell–platelet interaction. Using rescue experiments and functional blocking antibodies, we identified type I collagen as the key mediator of Hsp47-induced cancer cell–platelet interaction. We also found that Hsp47-dependent collagen deposition and platelet recruitment facilitated cancer cell clustering and extravasation in vitro. By analyzing DNA/RNA sequencing data generated from human breast cancer tissues, we showed that gene amplification and increased expression of Hsp47 were associated with cancer metastasis. These results suggest that targeting the Hsp47/collagen axis is a promising strategy to block cancer cell–platelet interaction and cancer colonization in secondary organs.
Rhizosphere microbiome mediates systemic root metabolite exudation by root-to-root signaling
Authors: Korenblum Elisa , Dong Yonghui , Szymanski Jedrzej , Panda Sayantan , Jozwiak Adam , Massalha Hassan , Meir Sagit , Rogachev Ilana , Aharoni Asaph
Published: February 2020

Microbial communities associated with roots confer specific functions to their hosts, thereby modulating plant growth, health, and productivity. Yet, seminal questions remain largely unaddressed including whether and how the rhizosphere microbiome modulates root metabolism and exudation and, consequently, how plants fine tune this complex belowground web of interactions. Here we show that, through a process termed systemically induced root exudation of metabolites (SIREM), different microbial communities induce specific systemic changes in tomato root exudation. For instance, systemic exudation of acylsugars secondary metabolites is triggered by local colonization of bacteria affiliated with the genusBacillus. Moreover, both leaf and systemic root metabolomes and transcriptomes change according to the rhizosphere microbial community structure. Analysis of the systemic root metabolome points to glycosylated azelaic acid as a potential microbiome-induced signaling molecule that is subsequently exuded as free azelaic acid. Our results demonstrate that rhizosphere microbiome assembly drives the SIREM process at the molecular and chemical levels. It highlights a thus-far unexplored long-distance signaling phenomenon that may regulate soil conditioning.
Dark biological superoxide production as a significant flux and sink of marine dissolved oxygen
Authors: Sutherland Kevin M. , Wankel Scott D. , Hansel Colleen M.
Published: February 2020

Significance

Extracellular production of the reactive oxygen species (ROS) superoxide results from the one-electron reduction of O
2
. Nearly all major groups of marine microbes produce extracellular superoxide. In this global estimate of marine microbial superoxide production we determine that dark extracellular superoxide production is ultimately a net sink of dissolved oxygen comparable in magnitude to other major terms in the marine oxygen cycle. This abundant source of superoxide to the marine water column provides evidence that extracellular ROS play a significant role in carbon oxidation and the redox cycling of metals in marine environments. Consideration of this significant reductive flux of dissolved oxygen is essential for field, laboratory, and modeling techniques for determining productivity and oxygen utilization in marine systems.
Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide
Authors: Barbarossa Valerio , Schmitt Rafael J. P. , Huijbregts Mark A. J. , Zarfl Christiane , King Henry , Schipper Aafke M.
Published: February 2020

Dams contribute to water security, energy supply, and flood protection but also fragment habitats of freshwater species. Yet, a global species-level assessment of dam-induced fragmentation is lacking. Here, we assessed the degree of fragmentation of the occurrence ranges of ∼10,000 lotic fish species worldwide due to ∼40,000 existing large dams and ∼3,700 additional future large hydropower dams. Per river basin, we quantified a connectivity index (CI) for each fish species by combining its occurrence range with a high-resolution hydrography and the locations of the dams. Ranges of nondiadromous fish species were more fragmented (less connected) (CI = 73 ± 28%; mean ± SD) than ranges of diadromous species (CI = 86 ± 19%). Current levels of fragmentation were highest in the United States, Europe, South Africa, India, and China. Increases in fragmentation due to future dams were especially high in the tropics, with declines in CI of ∼20 to 40 percentage points on average across the species in the Amazon, Niger, Congo, Salween, and Mekong basins. Our assessment can guide river management at multiple scales and in various domains, including strategic hydropower planning, identification of species and basins at risk, and prioritization of restoration measures, such as dam removal and construction of fish bypasses.
Canine olfactory detection of a vectored phytobacterial pathogen, Liberibacter asiaticus, and integration with disease control
Authors: Gottwald Timothy , Poole Gavin , McCollum Thomas , Hall David , Hartung John , Bai Jinhe , Luo Weiqi , Posny Drew , Duan Yong-Ping , Taylor Earl , da Graça John , Polek MaryLou , Louws Frank , Schneider William
Published: February 2020

Early detection and rapid response are crucial to avoid severe epidemics of exotic pathogens. However, most detection methods (molecular, serological, chemical) are logistically limited for large-scale survey of outbreaks due to intrinsic sampling issues and laboratory throughput. Evaluation of 10 canines trained for detection of a severe exotic phytobacterial arboreal pathogen,
Candidatus
Liberibacter asiaticus (
C
Las), demonstrated 0.9905 accuracy, 0.8579 sensitivity, and 0.9961 specificity. In a longitudinal study, cryptic
C
Las infections that remained subclinical visually were detected within 2 wk postinfection compared with 1 to 32 mo for qPCR. When allowed to interrogate a diverse range of in vivo pathogens infecting an international citrus pathogen collection, canines only reacted to Liberibacter pathogens of citrus and not to other bacterial, viral, or spiroplasma pathogens. Canines trained to detect
C
Las-infected citrus also alerted on
C
Las-infected tobacco and periwinkle,
C
Las-bearing psyllid insect vectors, and
C
Las cocultured with other bacteria but at
C
Las titers below the level of molecular detection. All of these observations suggest that canines can detect
C
Las directly rather than only host volatiles produced by the infection. Detection in orchards and residential properties was real time, ∼2 s per tree. Spatiotemporal epidemic simulations demonstrated that control of pathogen prevalence was possible and economically sustainable when canine detection was followed by intervention (i.e., culling infected individuals), whereas current methods of molecular (qPCR) and visual detection failed to contribute to the suppression of an exponential trajectory of infection.
Human MutLγ, the MLH1–MLH3 heterodimer, is an endonuclease that promotes DNA expansion
Authors: Kadyrova Lyudmila Y. , Gujar Vaibhavi , Burdett Vickers , Modrich Paul L. , Kadyrov Farid A.
Published: February 2020

MutL proteins are ubiquitous and play important roles in DNA metabolism. MutLγ (MLH1–MLH3 heterodimer) is a poorly understood member of the eukaryotic family of MutL proteins that has been implicated in triplet repeat expansion, but its action in this deleterious process has remained unknown. In humans, triplet repeat expansion is the molecular basis for ∼40 neurological disorders. In addition to MutLγ, triplet repeat expansion involves the mismatch recognition factor MutSβ (MSH2–MSH3 heterodimer). We show here that human MutLγ is an endonuclease that nicks DNA. Strikingly, incision of covalently closed, relaxed loop-containing DNA by human MutLγ is promoted by MutSβ and targeted to the strand opposite the loop. The resulting strand break licenses downstream events that lead to a DNA expansion event in human cell extracts. Our data imply that the mammalian MutLγ is a unique endonuclease that can initiate triplet repeat DNA expansions.
An ontogenetic switch drives the positive and negative selection of B cells
Authors: Xu Xijin , Deobagkar-Lele Mukta , Bull Katherine R. , Crockford Tanya L. , Mead Adam J. , Cribbs Adam P. , Sims David , Anzilotti Consuelo , Cornall Richard J.
Published: February 2020

Developing B cells can be positively or negatively selected by self-antigens, but the mechanisms that determine these outcomes are incompletely understood. Here, we show that a B cell intrinsic switch between positive and negative selection during ontogeny is determined by a change from Lin28b to let-7 gene expression. Ectopic expression of a Lin28b transgene in murine B cells restored the positive selection of autoreactive B-1 B cells by self-antigen in adult bone marrow. Analysis of antigen-specific immature B cells in early and late ontogeny identified Lin28b-dependent genes associated with B-1 B cell development, including
Arid3a
and
Bhleh41
, and Lin28b-independent effects are associated with the presence or absence of self-antigen. These findings identify cell intrinsic and extrinsic determinants of B cell fate during ontogeny and reconcile lineage and selection theories of B cell development. They explain how changes in the balance of positive and negative selection may be able to adapt to meet the immunological needs of an individual during its lifetime.
High-throughput quantitative microscopy-based half-life measurements of intravenously injected agents
Authors: Bracaglia Laura G. , Piotrowski-Daspit Alexandra S. , Lin Chun-Yu , Moscato Zoe M. , Wang Yongheng , Tietjen Gregory T. , Saltzman W. Mark
Published: February 2020

Significance

The effectiveness of systemically delivered therapeutics is dependent on their residence time in circulation, as this parameter influences the frequency of interaction with intended target sites prior to elimination from the body. Consequently, measurements of circulation half-life in relevant animal models of disease can be essential to therapeutic design. We designed a high-throughput quantitative microscopy-based approach to accurately measure the blood concentration and circulation half-life of intravenously administered fluorescently labeled agents using only a small amount of blood volume. This platform can be used to analyze large sample volumes from multivariable studies without the need for specialized equipment or extensive sample processing and has the potential to significantly accelerate preclinical therapeutic screening.
On the collision of rods in a quiescent fluid
Authors: Słomka Jonasz , Stocker Roman
Published: February 2020

Rods settling under gravity in a quiescent fluid can overcome the bottleneck associated with aggregation of equal-size spheres because they collide by virtue of their orientation-dependent settling velocity. We find the corresponding collision kernelΓrods=lβ1ΔρVrodg/(16Aμ), wherel,A, andVrodare the rods’ length, aspect ratio (length divided by width), and volume, respectively,Δρis the density difference between rods and fluid,μis the fluid’s dynamic viscosity,gis the gravitational acceleration, andβ1(A)is a geometrical parameter. We apply this formula to marine snow formation following a phytoplankton bloom. Over a broad range of aspect ratios, the formula predicts a similar or higher encounter rate between rods as compared to the encounter rate between (equal volume) spheres aggregating either by differential settling or due to turbulence. Since many phytoplankton species are elongated, these results suggest that collisions induced by the orientation-dependent settling velocity can contribute significantly to marine snow formation, and that marine snow composed of elongated phytoplankton cells can form at high rates also in the absence of turbulence.