bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical layer security of interference aligned mixed RF/unified‐FSO relaying network
Authors: Tubail Deeb , El‐Absi Mohammed , Salhab Anas , Ikki Salama , Zummo Salam , Kaiser Thomas
Published: July 2020

In this study, the authors secure the mixed radio frequency/free space optical (FSO) relay‐aided interference aligned system using a proposed physical layer security algorithm. This algorithm reduces the quality of the received signal at the eavesdropper through two procedures. First, it minimises the data transmission power from the legitimate users and the relays. Second, it jams the eavesdropper by broadcasting artificial noise from the users and the relays. Therefore, a joint optimisation problem is formulated to degrade the received signal at the eavesdropper from the users and the relays and to maximise the jamming artificial noise power, which is solved using an iterative optimisation algorithm beside a semi‐definitive programming algorithm. Furthermore, the pre‐coding and decoding matrices of the users and the relay are designed to enable the legitimate users to cancel the artificial noise, while the eavesdropper is disabled from distinguishing the artificial noise from the real streams. Moreover, the security performance of the proposed algorithm is analysed, and the impact of the FSO link's state on the security performance is studied. The extensive simulation results show the efficiency of the proposed algorithm and illustrate the role of the FSO link's state on the security performance.
Tidal disruption versus planetesimal collisions as possible origins for the dispersing dust cloud around Fomalhaut
Authors: Janson Markus , Wu Yanqin , Cataldi Gianni , Brandeker Alexis
Published: July 2020

Recent analysis suggests that the faint optical point source observed around Fomalhaut from 2004–2014 (Fomalhaut b) is gradually fading and expanding, supporting the case that it may be a dispersing dust cloud resulting from the sudden disruption of a planetesimal. These types of disruptions may arise from catastrophic collisions of planetesimals, which are perturbed from their original orbits in the Fomalhaut dust ring by nearby giant planets. However, disruptions can also occur when the planetesimals pass within the tidal disruption field of the planet(s) that perturbed them in the first place, similar to the Shoemaker-Levy event observed in the Solar System. Given that a gravitationally focusing giant planet has a much larger interaction cross-section than a planetesimal, tidal disruption events can match or outnumber planetesimal collision events in realistic regions of parameter space. Intriguingly, the Fomalhaut dust cloud offers an opportunity to directly distinguish between these scenarios. A tidal disruption scenario leads to a very specific prediction of ephemerides for the planet causing the event. At a most probable mass of 66 M⊕, a semi-major axis of 117 AU, and a system age of 400–500 Myr, this planet would be readily detectable with the James Webb Space Telescope. The presence or absence of this planet at the specific, predicted position is therefore a distinctive indicator of whether the dispersing cloud originated from a collision of two planetesimals or from the disruption of a planetesimal in the tidal field of a giant planet.
Übermäßiges Körpergewicht und Krebsrisiko
Authors: Scherübl Hans
Published: July 2020

Excess body weight (EBW) is the second most important and potentially modifiable risk factor of cancer in Germany. The longer and the more excess body weight a person has, the higher the cancer risk. About 60 % of adult Germans have EBW (BMI ≥ 25.0 kg/m²) and more than 23 % are obese (BMI ≥ 30.0 kg/m²). Excess body weight is causally associated with colorectal, esophageal (adenocarcinoma), gastric (cardia), pancreatic, biliary, hepatocellular, kidney, thyroid, breast (postmenopausal), endometrial and ovarian cancer as well as multiple myeloma and meningioma. In recent years, more and more young adults (20–40 years) were diagnosed with EBW-associated tumors. People with EBW should be encouraged to join programs of cancer screening. Keeping a healthy weight is a major public health concern in Germany.
Was begünstigt den Fachkräftemangel? – Wissenschaft nachgefragt
Authors: Veit Katrin
Published: July 2020

Der schwerwiegende Fachkräftemangel steht drohend vor uns. Um heute einen Termin in einer Physiotherapiepraxis zu bekommen, warten Patienten in manchen Regionen drei Wochen oder länger. Bei den Hausbesuchen liegt die Wartezeit noch höher. Nach möglichen Ursachen und was dagegen getan werden kann, hat eine Gruppe der Universität zu Lübeck akademisierte Therapeuten gefragt.
Biological Activity of Matricaria chamomilla Essential Oils of
Various Chemotypes
Authors: Höferl Martina , Wanner Jürgen , Tabanca Nurhayat , Ali Abbas , Gochev Velizar , Schmidt Erich , Kaul Vijay K. , Singh Virendra , Jirovetz Leopold
Published: July 2020

The essential oil of Matricaria chamomilla L., which is commonly used for
medicinal and cosmetic purposes, can be differentiated between several
chemotypes. In the current study, six essential chamomile oil samples of various
origins (four of commercial sources, one of cultivation, one of wild collection)
were examined regarding their composition and biological activities,
i. e., antibacterial, antifungal, mosquito repellent, and larvicidal
effects. GC-MS analyses revealed that the samples largely varied in composition
and could be attributed to various chemotypes. In contrast to the other two
samples, the four commercial samples were unusually high in
trans-β-farnesene. The overall antimicrobial effects
were only moderate, but it could be shown that a higher content in
α-bisabolol and a smaller in α-bisabolol
oxides A and B had a positive effect on overall activity. All samples had a
biting deterrent effect comparable to DEET. Higher concentrations of
(Z )- and (E )-spiroethers improved larvicidal
activity, whereas trans-β-farnesene had the opposite
effect. In conclusion, the importance of α-bisabolol for the
biological activity of chamomile essential oil could be demonstrated.
Severe Lactic Acidosis in a Critically Ill Child: Think About Thiamine! A Case Report
Authors: Didisheim Clémence , Ballhausen Diana , Choucair Marie-Louise , Longchamp David , Natterer Julia , Ferry Thomas , Perez Marie-Hélène , Amiet Vivianne
Published: July 2020

In this article, we presented a teenager, in maintenance chemotherapy for leukemia, who was admitted for digestive symptoms related to a parasitic infection and required nutritional support with parenteral nutrition. After 6 weeks, his condition worsened with refractory shock of presumed septic origin, necessitating extracorporeal membrane oxygenation. Despite hemodynamic stabilization, his lactic acidosis worsened until thiamine supplementation was started. Lactate normalized within 12 hours. Thiamine is an essential coenzyme in aerobic glycolysis, and deficiency leads to lactate accumulation through anaerobic glycolysis. Thiamine deficiency is uncommon in the pediatric population. However, it should be considered in patients at risk of nutritional deficiencies with lactic acidosis of unknown origin.
Progeroid Syndrome with Mitral Regurgitation: A Rare Case Report
Authors: Chakravarthi D. P. Kalyana , Kishore Yalampati Rama , Naveen Kumar M.
Published: July 2020

Progeroid syndromes (PS) involve the disorder of early aging. Although survival of progeria syndrome patients is nearly 15 years as per literature, the adult onset progeroid starts manifesting in the third decade. Here, we are presenting a rare case of progeroid at the age of 45 years with mitral regurgitation (MR). The patient has alopecia, dry skin, frontal bossing, up staring eyes with bilateral corneal opacities, prominent nose with parrot beak appearance, thin upper lip, large, low-set ears, periorbital hyperpigmentation, micrognathia, retrognathia, and hyperpigmentation over lower abdomen/both feet and hands. Facial and skeletal manifestation are the major clinical features of the PS; along with the characteristics mentioned above, the patient also had severe eccentric MR. This patient has PS with mitral valve prolapse and severe MR. Most of the features of progeria exist in this patient, which manifested at a younger age. However, the progression of the external features and survival up to 45 years favors PS instead of progeria. Therefore, genetic analysis is mandatory to confirm. We are reporting this case due to the rarity of onset of symptoms within a younger age group; however, the progression of the disease was very slow, which may be a another variant of progeria/PS.
Mental Health Issues in Coronavirus Disease 2019 Pandemic: Evolving a Strategy
Authors: Patil Vaibhav , Gupta Ankit , Chadda Rakesh Kumar
Published: July 2020

Coronavirus disease 2019 (COVID-19) pandemic has become a global health emergency in a short span of time. Novel kind of the disease, highly infectious nature, rapid progress with serious medical complications and risk of death, and absence of effective treatment and vaccine have all added to a community fear. Need for social distancing, social isolation, and quarantine in contacts further contributes to the fear and also creates a stigma. Declaration of lockdown in many parts of the world to prevent spread of illness has been associated with socioeconomic consequences with great loss to the world economy as well unemployment in a large section of the population. All these factors impose a high risk of mental health problems like anxiety, fear, worries, sleep disturbances, depression, etc. in the general population, and also worsening of the existing symptoms in persons with existing mental illness. The impact of the pandemic on mental health is likely to be long lasting, and a great challenge to the mental health professionals and the policy makers. This paper discusses various strategies to effectively manage the mental health issues in the light of limited availability of mental health resources and restricted access to health services due to lockdown in low-resource settings.
Ill-posedness of the Thirring model below the critical regularity
Authors: Selberg Sigmund , Tesfahun Achenef
Published: July 2020

We consider an L2-critical cubic Dirac equation in one space-dimension known as the Thirring model. Global well-posedness in L2 for this equation was proved by Candy. Here, we show that Candy’s result is sharp in the sense that the equation is ill posed in Lp for 1 ≤ p < 2 and in the massless case also in Hs with s < 0.
Fixed-time terminal synergetic observer for synchronization of fractional-order chaotic systems
Authors: Balamash A. S. , Bettayeb M. , Djennoune S. , Al-Saggaf U. M. , Moinuddin M.
Published: July 2020

In this paper, a fixed-time terminal synergetic observer for synchronization of fractional-order nonlinear chaotic systems is proposed. First, fixed-time terminal attractors for fractional-order nonlinear systems are introduced on the basis of fixed-time stability of integer-order nonlinear differential equations and on defining particular fractional-order macro-variables. Second, a new synergetic observer dedicated to the synchronization of fractional-order chaotic systems is developed. The proposed observer converges in a predefined fixed-time uniformly bounded with respect to initial conditions. Thanks to the step-by-step procedure, only one communication channel is used to achieve the synchronization. Third, a fixed-time synergetic extended observer with unknown input is constructed to simultaneously estimate the state variables and to recover the unknown input. Finally, computer simulations are performed to illustrate the efficiency of the proposed synchronization method and its application in a secure communication scheme.
A monolithic artificial iconic memory based on highly stable perovskite-metal multilayers
Authors: Guan Xinwei , Wang Yutao , Lin Chun-Ho , Hu Long , Ge Shuaipeng , Wan Tao , Younis Adnan , Li Feng , Cui Yimin , Qi Dong-Chen , Chu Dewei , Chen Xiao Dong , Wu Tom
Published: July 2020

Artificial iconic memories, also called photomemories, are new types of nonvolatile memory that can simultaneously detect and store light information in a monolithic device. Several approaches have been proposed to construct artificial iconic memories, such as three-terminal field effect transistors, which can achieve an effective control of the gate voltage and external light terminals. The drawbacks in constructing these memories involve complicated fabrication processes, and the resulting performance of, for example, perovskite transistor-type photomemories is limited by the low carrier mobilities and poor ambient stabilities, whereas architectures based on floating gate modulations entail strict interface engineering and poor device reliability. In this paper, we propose a novel monolithic artificial iconic memory with a multilayer architecture of indium tin oxide/perovskite/gold/perovskite/silver, which combines the memory and photodetector functionalities of perovskites in an integrated device. The bottom perovskite layer plays the role of a photodetector, modulating the voltage bias on the top perovskite layer that serves as a resistive switching memory. This multilayer perovskite device can store photo-sensing data in its resistive states, with a memory retention of 5 × 103 s and ambient stability longer than sixty days. As a prototype demonstration, a 7 × 7 artificial iconic memory array is constructed to detect and store data on light intensity distribution, enabling a nonvolatile imaging functionality. Our work provides a new platform for designing perovskite-based architectures with simultaneous light detection and data storage capabilities.
Systematic method for studying single-electron transistors
Authors: Dobrynin D. M. , Shorokhov V. V.
Published: July 2020

We present a thorough classification of the electronic transport patterns of single-electron transistors (SETs) using a two-letter notation, based on the symmetry properties of SETs and a nondimensionalization procedure. We find five unique symmetry types of SETs: one symmetric and four asymmetric. For these types and the corresponding dimensionless transistor parameter sets, denoted by the two-letter scheme, we calculate and compare current–voltage curves, modulation curves, charge stability diagrams, and the average and standard deviation of the number of excess electrons on the transistor island. The simulation is performed using the mean of the recurrent solution method for the system of kinetic equations for the charge probability distribution function. On the basis of the simulation results, we analyze the properties of asymmetric SETs. We also consider the effect of asymmetry in the transistor bias voltage and show that this effect can be compensated by renormalization of the left and right junction capacitances. In addition, we propose a measurement technique that can be used to determine the voltage bias asymmetry ratio in real experiments. Finally, using the Bardeen approximation for the tunnel matrix element and the parallel-plate capacitor approximation, we estimate the geometric features of the tunnel junctions.
Direct and trapping-mediated pathways to dissociative chemisorption: CH4 dissociation on Ir(111) with step defects
Authors: Jackson Bret
Published: July 2020

The indirect chemisorption of methane on a transition metal, where the incident molecule first traps onto the surface and then reacts from a physisorbed molecular state, has only been observed on Ir(111) and Ir(110) at very low collision energies. We use quantum scattering methods to describe the direct reaction of methane on Ir(111) at high energy and rate theory to examine the indirect pathway at low energy. Overall, we find good agreement with the experiment with respect to the variation of sticking with the incident energy, surface temperature, and vibrational state. Compared with methane dissociation on other metals, vibrational excitation is found to be less effective at promoting the reaction, while coupling to the lattice motion is unusually strong. We show how step defects, even at low concentrations, can contribute significantly to indirect chemisorption. We explore indirect chemisorption on Ni(111) and Pt(111) and find that the indirect path can be important when relaxed lattice barriers are sufficiently low and the temperature is sufficiently high so that the indirect sticking is within detection limits and the incident energy is low enough so that the trapping is large and the direct component is small.
Optical properties of charged excitons in two-dimensional semiconductors
Authors: Glazov M. M.
Published: July 2020

Strong Coulomb interaction in atomically thin transition metal dichalcogenides makes these systems particularly promising for studies of excitonic physics. Of special interest are the manifestations of the charged excitons, also known as trions, in the optical properties of two-dimensional semiconductors. In order to describe the optical response of such a system, the exciton interaction with resident electrons should be explicitly taken into account. In this paper, we demonstrate that this can be done in both the trion (essentially, few-particle) and Fermi-polaron (many-body) approaches, which produce equivalent results, provided that the electron density is sufficiently low and the trion binding energy is much smaller than the exciton one. Here, we consider the oscillator strengths of the optical transitions related to the charged excitons, fine structure of trions, and Zeeman effect, as well as photoluminescence of trions illustrating the applicability of both few-particle and many-body models.
Spin–orbit torque based physical unclonable function
Authors: Finocchio G. , Moriyama T. , De Rose R. , Siracusano G. , Lanuzza M. , Puliafito V. , Chiappini S. , Crupi F. , Zeng Z. , Ono T. , Carpentieri M.
Published: July 2020

This paper introduces the concept of spin–orbit-torque-magnetic random access memory (SOT-MRAM) based physical unclonable function (PUF). The secret of the PUF is stored into a random state of a matrix of perpendicular SOT-MRAMs. Here, we show experimentally and with micromagnetic simulations that this random state is driven by the intrinsic nonlinear dynamics of the free layer of the memory excited by the SOT. In detail, a large enough current drives the magnetization along an in-plane direction. Once the current is removed, the in-plane magnetic state becomes unstable evolving toward one of the two perpendicular stable configurations randomly. In addition, we propose a hybrid CMOS/spintronics model to simulate a PUF realized by an array of 16 × 16 SOT-MRAM cells and evaluate the electrical characteristics. Hardware authentication based on this PUF scheme has several characteristics, such as CMOS-compatibility, non-volatility (no power consumption in standby mode), reconfigurability (the secret can be reprogrammed), and scalability, which can move a step forward the design of spintronic devices for application in security.
Anomalous Nernst effect in ferromagnetic Mn5Ge3Cx thin films on insulating sapphire
Authors: Kraft R. , Srichandan S. , Fischer G. , Sürgers C.
Published: July 2020

Investigating the thermoelectric properties of ferromagnets is important for the development of future microelectronic devices for efficient energy conversion purposes. Ferromagnetic Mn5Ge3Cx thin films with a Curie temperature up to TC=450K well above room temperature are potential candidates for spintronic applications by integration into CMOS heterostructures. In this work, the thermoelectric power, in particular, the anomalous Nernst effect (ANE), has been investigated experimentally for magnetron sputtered thin films on sapphire (112¯0) substrates. The ANE gradually increases with increasing carbon content x up to a maximum value obtained for x=0.8 in line with the earlier investigations of the magnetization and anomalous Hall effect. The ANE is strongly enhanced by a factor three compared to the parent Mn5Ge3 compound. However, for x=0.8, we observe a clear deviation of the calculated ANE from the measured values.
Heterojunction of CuO nanoclusters with TiO2 for photo-oxidation of organic compounds and for hydrogen production
Authors: Méndez-Medrano Maria Guadalupe , Kowalska Ewa , Ohtani Bunsho , Bahena Uribe Daniel , Colbeau-Justin Christophe , Rau Sven , Rodríguez-López José Luis , Remita Hynd
Published: July 2020

Heterojunctions of small CuO nanoclusters (synthesized by radiolysis) with TiO2 (commercial P25) induced a photocatalytic activity under visible light irradiation in a wide range of wavelengths due to the narrow bandgap of CuO nanoclusters of around 1.7 eV. The optical, chemical, and electrical properties of these composite nanomaterials were studied. The photocatalytic properties of bare and modified TiO2–P25 were studied for water purification (photooxidation of organic compounds such as phenol and 2-propanol) and for hydrogen generation under visible light irradiation. Time resolved microwave conductivity signals showed activation of TiO2 under visible light, proving the injection of electrons from CuO nanoclusters to the conduction band of TiO2–P25. The modified materials showed high photocatalytic activity under visible light. The important role of charge-carriers was demonstrated for both photoreduction and photooxidation reactions.
First example of hybridisation between two Australian figs (Moraceae)
Authors: Wilde Brendan C. , Rutherford Susan , van der Merwe Marlien , Murray Megan L. , Rossetto Maurizio
Published: July 2020

The chance discovery of an unusual Ficus specimen near Katherine in the Northern Territory prompted an investigation into hybridisation between two morphologically distinct endemic Australian sandpaper figs, Ficus aculeata A.Cunn. ex Miq. and F. coronulata Miq. In this study, genome-wide scans and morphological measurements were used to investigate the perceived hybridisation by using herbarium and freshly collected samples. Most of the putative hybrids displayed a wide variety of intermediate morphology and some individuals had characteristics consistent with the description of a third species, F. carpentariensis D.J.Dixon. Both genomic and morphometric results provided evidence of naturally occurring hybridisation events within Ficus. Additionally, the findings from this study showed possible taxonomic issues within the Northern Australian sandpaper figs that warrant further investigation.
A review of the fern genus Pellaea (Pteridaceae) in Australasia
Authors: Brownsey Patrick J. , Ohlsen Daniel J. , Shepherd Lara D. , Bouma Whitney L. M. , May Erin L. , Bayly Michael J. , Perrie Leon R.
Published: July 2020

Five indigenous species of Pellaea in Australasia belong to section Platyloma. Their taxonomic history is outlined, morphological, cytological and genetic evidence for their recognition reviewed, and new morphological and chloroplast DNA-sequence data provided. Australian plants of P. falcata (R.Br.) Fée are diploid and have longer, narrower pinnae than do New Zealand plants previously referred to P. falcata, which are tetraploid. Evidence indicates that P. falcata does not occur in New Zealand, and that collections so-named are P. rotundifolia (G.Forst.) Hook. Chloroplast DNA sequences are uninformative in distinguishing Australian P. falcata from New Zealand P. rotundifolia, but show that Australian P. nana is distinct from both. Sequence data also show that Australian and New Zealand populations of P. calidirupium Brownsey & Lovis are closely related, and that Australian P. paradoxa (R.Br.) Hook. is distinct from other Australian species. Although P. falcata is diploid and P. rotundifolia tetraploid, P. calidirupium, P. nana (Hook.) Bostock and P. paradoxa each contain multiple ploidy levels. Diploid populations of Pellaea species are confined to Australia, and only tetraploids are known in New Zealand. Evolution of the group probably involved hybridisation, autoploidy, alloploidy, and possibly apomixis. Further investigation is required to resolve the status of populations from Mount Maroon, Queensland and the Kermadec Islands.
Linking nest microhabitat selection to nest survival within declining pheasant populations in the Central Valley of California
Authors: Dwight Ian A. , Vogt Jessica H. , Coates Peter S. , Fleskes Joseph P. , Connelly Daniel P. , Gardner Scott C.
Published: July 2020

Abstract
ContextThe ring-necked pheasant (Phasianus colchicus) has experienced considerable population declines in recent decades, especially in agricultural environments of the Central Valley of California. Although large-scale changes in land cover have been reported as an important driver of population dynamics, the effects of microhabitat conditions on specific demographic rates (e.g. nesting) are largely unknown.
AimsOur goal was to identify the key microhabitat factors that contribute to wild pheasant fitness by linking individual-level selection of each microhabitat characteristic to the survival of their nests within the California Central Valley.
MethodsWe radio- or GPS-marked 190 female ring-necked pheasants within five study areas and measured nest-site characteristics and nest fates during 2013–2017. Specifically, we modeled microhabitat selection using vegetation covariates measured at nest sites and random sites and then modeled nest survival as a function of selecting each microhabitat characteristic.
Key resultsFemale pheasants tended to select nest sites with greater proportions of herbaceous cover and avoided areas with greater proportions of bare-ground. Specifically, perennial grass cover was the most explanatory factor with regard to nest survival, but selection for increasing visual obstruction alone was not shown to have a significant effect on survival. Further, we found strong evidence that pheasants selecting sites with greater perennial grass height were more likely to have successful nests.
ConclusionsAlthough pheasants will select many types of vegetation available as cover, our models provided evidence that perennial grasses are more beneficial than other cover types to pheasants selecting nesting sites.
ImplicationsFocusing management actions on promoting perennial grass cover and increased heights at the microsite level, in lieu of other vegetative modifications, may provide improved quality of habitat for nesting pheasants and, perhaps, result in increased productivity. This is especially important if cover is limited during specific times of the nesting period. Understanding how microhabitat selection influences fitness can help land managers develop strategies to increase the sustainability of hunted populations of this popular game-bird species.
Robustness of plant quantitative disease resistance is provided by a decentralized immune network
Authors: Delplace Florent , Huard-Chauveau Carine , Dubiella Ullrich , Khafif Mehdi , Alvarez Eva , Langin Gautier , Roux Fabrice , Peyraud Rémi , Roby Dominique
Published: July 2020

Significance

Molecular studies of plant immune responses have mainly focused on qualitative resistance, a form of immunity determined by a few large effect genes. In contrast, very limited information exists about quantitative disease resistance (QDR), although it is extensively observed in wild and crop species. We used systems biology approaches to describe this form of immunity in
Arabidopsis thaliana
. On the basis of gene regulation studies and search for protein–protein interactions, we report the reconstruction of a highly interconnected and distributed network, organized in five modules with differential robustness to genetic mutations. These studies revealed key functions of QDR, mainly distinct from those previously identified for plant immunity, and shed some light on the complexity of this plant immune response.
Structure-based development of a subtype-selective orexin 1 receptor antagonist
Authors: Hellmann Jan , Drabek Matthäus , Yin Jie , Gunera Jakub , Pröll Theresa , Kraus Frank , Langmead Christopher J. , Hübner Harald , Weikert Dorothee , Kolb Peter , Rosenbaum Daniel M. , Gmeiner Peter
Published: July 2020

Significance

Orexin receptors belong to the superfamily of G-protein–coupled receptors (GPCRs) which represent the largest class of drug targets in humans. Despite the recent progress in structural biology, the development of subtype-selective orexin receptor and GPCR ligands in general remains challenging, due to the high sequence similarity among individual receptor subtypes. However, subtype-selective molecules are key to discerning the individual contributions of receptor subtypes to (patho-)physiology. Starting from the clinically used, non–subtype-selective orexin receptor antagonist suvorexant, we demonstrate how docking, crystallography, medicinal chemistry, and in vitro pharmacology can be combined to exploit single amino acid sequence differences for the discovery of subtype-selective probes. Such compounds will help to better understand orexin receptor pharmacology and develop promising drug candidates.
Wide lag time distributions break a trade-off between reproduction and survival in bacteria
Authors: Moreno-Gámez Stefany , Kiviet Daniel J. , Vulin Clément , Schlegel Susan , Schlegel Kim , van Doorn G. Sander , Ackermann Martin
Published: July 2020

Significance

The biology of many microorganisms has been adapted to a feast-and-famine lifestyle. Thus, understanding population dynamics during transitions from starvation to resource abundance is important for fundamental and applied reasons. Here, we study starved populations of bacteria encountering new resources and ask how the behavior of single cells gives rise to emergent population-level traits. We find that growth and survival of populations are dominated by phenotypic minorities: small subpopulations with extreme lag times. As a consequence, starved populations of bacteria can break a fundamental life history trade-off between growth and survival by evolving phenotypic variation in lag time. By showing why bacteria can sustain subpopulations with long lag times our findings can explain the prevalence of antibiotic tolerance by lag.
Tumor cell lysate-loaded immunostimulatory spherical nucleic acids as therapeutics for triple-negative breast cancer
Authors: Callmann Cassandra E. , Cole Lisa E. , Kusmierz Caroline D. , Huang Ziyin , Horiuchi Dai , Mirkin Chad A.
Published: July 2020

Significance

In mouse models of triple-negative breast cancer, we show that the oxidation of tumor cells prior to lysate generation, coupled with their compartmentalization in the core of liposomal spherical nucleic acids (SNAs) comprised of adjuvant DNA, yields a powerful immunotherapeutic that significantly inhibits tumor growth, dramatically extends survival, and promotes a tumoricidal immune cell population within the tumor microenvironment. Specifically, this work points toward the importance of properly packaging and presenting the adjuvant and antigens such that biodistribution, dendritic cell activation, and therapeutic efficacy can be controlled.
Structural mechanism of helicase loading onto replication origin DNA by ORC-Cdc6
Authors: Yuan Zuanning , Schneider Sarah , Dodd Thomas , Riera Alberto , Bai Lin , Yan Chunli , Barbon Marta , Magdalou Indiana , Ivanov Ivaylo , Stillman Bruce , Li Huilin , Speck Christian
Published: July 2020

Significance

The loading of the core Mcm2-7 helicase onto origin DNA is essential for the formation of replication forks and genomic stability. Here, we report two cryo-electron microscopy (cryo-EM) structures that capture helicase loader–helicase complexes just prior to DNA insertion. These pre-loading structures, combined with a computational simulation of the dynamic transition from the pre-loading state to the loaded state, provide crucial insights into the mechanism required for topologically linking the helicase to DNA. The helicase loading system is highly conserved from yeast to human, which means that the molecular principles described here for the yeast system are likely applicable to the human system.
A Dutch dose of dissent
Authors: Labrie Nanon , Akkermans Aranka , Hample Dale
Published: July 2020

The Dutch are often thought of as direct, verbally aggressive, and argumentative. Yet, evidence for this
stereotype is lacking. This study explores argumentative predispositions in the Netherlands. In a survey, Dutch students’
(N = 133) argumentativeness, verbal aggressiveness, argument frames, and conflict personalization were
measured. The effects of gender and education were assessed. To explore the role of Dutch culture on argumentativeness,
comparisons to U.S. students (benchmark) were made. Overall, Dutch students showed orientations, expectations, and understandings
of argumentation as being useful and enjoyable, and seemed to experience argumentation predominantly positive. Males were more
aggressive than females, and students in higher professional and university (preparatory) education were more constructive than
students in vocational education. In contrast to expectations, Dutch students did not appear more predisposed to argue than U.S.
students. Dutch students prioritized prosocial behaviors and professional reflection, thereby tempering aggression in arguing.
Thus, argumentativeness is certainly not merely (stereo)typically Dutch.
Black Rising: An Editorial Note on the Increasing Popularity of a US American Racial Ethnonym
Authors: Nick I. M.
Published: July 2020

In historic protests sparked by the wrongful deaths of US civilians, demonstrators have taken to the streets in record numbers demanding justice and an end to institutionalized racism. US media coverage of this movement has frequently utilized the racial ethnonym Black as opposed to African(-)American. As this note discusses, this choice in nomenclature may not only be due to the increasing prominence of the Black Lives Matter Movement. It may also be indicative of earlier, large-scale shifts in autonymy. This note presents some of the demographic, linguistic, and sociopolitical factors that may well have played a role in the rising use of Black as both an ethnoracial and political identifier.
How does an RNA selfie work? EV‐associated RNA in innate immunity as self or danger
Authors: Xiao Yu , Driedonks Tom , Witwer Kenneth W. , Wang Qian , Yin Hang
Published: July 2020

Innate immunity is a first line of defence against danger. Exogenous pathogen‐ or microbe‐associated molecular patterns (PAMPs or MAMPs) trigger innate immune responses through well‐understood cellular pathways. In contrast, endogenous damage‐associated molecular patterns (DAMPs) convey “danger signals” via their (mis)localization or modification. Both MAMPs and DAMPs are often communicated on or within extracellular vesicles (EVs). Despite growing evidence for the importance of EVs and their cargo in modulating innate immune responses, in some cases, it is unclear how EV‐transported molecules are sensed as abnormal. In particular, EVs constitutively carry RNA, which is also abundant in the cytoplasm. How, then, would RNA convey a danger signal as a cargo of EVs? In this Perspective, we offer some thoughts on how EV‐associated RNAs might raise the alarm for innate immune responses – or silence them.
Dynamics of chiral cosmology
Authors: Paliathanasis Andronikos
Published: July 2020

We perform a detailed analysis for the dynamics of chiral cosmology in a spatially flat Friedmann–Lemaître–Robertson–Walker Universe with a mixed potential term. The stationary points are categorized in four families. Previous results in the literature are recovered while new phases in the cosmological evolution are found. From our analysis we find nine different cosmological solutions, the eight describe scaling solutions, where the one is that of a pressureless fluid, while only one de Sitter solution is recovered.
Searching for MHz gravitational waves from harmonic sources
Authors: Martinez Jeronimo G. C. , Kamai Brittany
Published: July 2020

A MHz gravitational wave search for harmonic sources was conducted using a 704 h dataset obtained from the Holometer, a pair of 40 m power recycled Michelson interferometers. Our search was designed to look for cosmic string loops and eccentric black hole binaries in an entirely unexplored frequency range from 1 to 25 MHz. The measured cross-spectral density between both interferometers was used to perform four different searches. First, we search to identify any fundamental frequencies bins that have excess power above 5σ. Second, we reduce the per-bin threshold on any individual frequency bin by employing that a fundamental frequency and its harmonics all collectively lie above a threshold. We vary the number of harmonics searched over from n = 4 up to n = 23. Third, we perform an agnostic approach to identify harmonic candidates that may have a single contaminated frequency bin or follow a power-law dependence. Lastly, we expand on the agnostic approach for individual candidates and search for a potential underlying population of harmonic sources. Each method was tested on the interferometer dataset, as well as a dark noise, photon shot-noise-limited, and simulated Gaussian-noise datasets. We conclude that these four different search methods did not find any candidate frequencies that would be consistent with harmonic sources. This work presents a new way of searching for gravitational wave candidates, which allowed us to survey a previously unexplored frequency range.
Measurement of the tilt of the Earth’s axis during a lunar
eclipse using a simple method
Authors: Kucukozer Huseyin , Yurumezoglu Kemal , Kucukozer H Asuman , Suat Isıldak R
Published: July 2020

In this study, the tilt of the Earth’s axis was measured during a lunar
eclipse using a telescope based on the angle between the lunar orbit and
ecliptic planes being considered as approximately zero. The presented method not
only offers a practical and reliable way of measuring the axial tilt of the
Earth during a lunar eclipse but also helps in providing a higher
argumentation-based conceptual understanding and awareness of astronomical
events and their results through the combination of observation with
measurement.
Broadband energy harvesting based on one-to-one internal resonance*
Authors: Jiang Wen-An , Ma Xin-Dong , Han Xiu-Jing , Chen Li-Qun , Bi Qin-Sheng
Published: July 2020

We design an electromechanical transducer harvesting system with one-to-one internal resonance that can emerge a broader spectrum vibrations. The novel harvester is composed of a Duffing electrical circuit coupled to a mobile rod, and the coupling between both components is realized via the electromagnetic force. Approximate analytical solutions of the electromechanical system are carried out by introducing the multiple scales analysis, also the nonlinear modulation equation for one-to-one internal resonance is obtained. The character of broadband harvesting performance are analyzed, the two peaks and one jump phenomenon bending to the right for variation of control parameters are observed. It is shown that an advanced bandwidth over a corresponding linear model that does not possess a modal energy interchange.
Effects of temperature and pressure on OH laser-induced fluorescence exciting A–X (1,0) transition at high pressures*
Authors: Tu Xiaobo , Wang Linsen , Qi Xinhua , Yan Bo , Mu Jinhe , Chen Shuang
Published: July 2020

The effects of temperature and pressure on laser-induced fluorescence (LIF) of OH are numerically studied under the excitation of A–X (1,0) transition at high pressures. A detailed theoretical analysis is carried out to reveal the physical processes of LIF. It is shown that high pressure LIF measurements get greatly complicated by the variations of pressure- and temperature-dependent parameters, such as Boltzmann fraction, absorption lineshape broadening, central-frequency shifting, and collisional quenching. Operations at high pressures require a careful choice of an excitation line, and the Q
1(8) line in the A–X (1,0) band of OH is selected due to its minimum temperature dependence through the calculation of Boltzmann fraction. The absorption spectra of OH become much broader as pressure increases, leading to a smaller overlap integral and thus smaller excitation efficiency. The central-frequency shifting cannot be omitted at high pressures, and should be taken into account when setting the excitation frequency. The fluorescence yield is estimated based on the LASKIN calculation. Finally, OH-LIF measurements were conducted on flat stoichiometric CH4/air flames at high pressures. And both the numerical and experimental results illustrate that the pressure dependence of fluorescence yield is dominated, and the fluorescence yield is approximately inversely proportional to pressure. These results illustrate the physical processes of OH-LIF and provide useful guidelines for high-pressure application of OH-LIF.
Two ultra-stable novel allotropes of tellurium few-layers*
Authors: Yan Changlin , Wang Cong , Zhou Linwei , Guo Pengjie , Liu Kai , Lu Zhong-Yi , Cheng Zhihai , Chai Yang , Pan Anlian , Ji Wei
Published: July 2020

At least four two- or quasi-one-dimensional allotropes and a mixture of them were theoretically predicted or experimentally observed for low-dimensional Te, namely the α, β, γ, δ, and chiral-α + δ phases. Among them the γ and α phases were found to be the most stable phases for monolayer and thicker layers, respectively. Here, we found two novel low-dimensional phases, namely the ε and ζ phases. The ζ phase is over 29 meV/Te more stable than the most stable monolayer γ phase, and the ε phase shows comparable stability with the most stable monolayer γ phase. The energetic difference between the ζ and α phases reduces with respect to the increased layer thickness and vanishes at the four-layer (12-sublayer) thickness, while this thickness increases under change doping. Both ε and ζ phases are metallic chains and layers, respectively. The ζ phase, with very strong interlayer coupling, shows quantum well states in its layer-dependent bandstructures. These results provide significantly insight into the understanding of polytypism in Te few-layers and may boost tremendous studies on properties of various few-layer phases.
Active Brownian particles simulated in molecular dynamics*
Authors: Wang Liya , Xu Xinpeng , Li Zhigang , Qian Tiezheng
Published: July 2020

In the numerical studies of active particles, models consisting of a solid body and a fluid body have been well established and widely used. In this work, such an active Brownian particle (ABP) is realized in molecular dynamics (MD) simulations. Immersed in a fluid, each ABP consists of a head particle and a spherical phantom region of fluid where the flagellum of a microswimmer takes effect. Quantitative control over the orientational persistence time is achieved via an external stochastic dynamics. This control makes it possible to validate ABP’s diffusion property in a wide range of particle activity. In molecular description, the axial velocity of ABP exhibits a Gaussian distribution. Its mean value defines the active velocity which increases with the active force linearly, but shows no dependence on the rotational diffusion coefficient. For the active diffusion coefficient measured in free space, it shows semi-quantitative agreement with the analytical result predicted by a minimal ABP model. Furthermore, the active diffusion coefficient is also calculated by performing a quantitative analysis on the ABP’s distribution along x axis in a confinement potential. Comparing the active diffusion coefficients in the above two cases (in free space and in confinement), the validity of the ABP modeling implemented in MD simulations is confirmed. Possible reasons for the small deviation between the two diffusion coefficients are also discussed.
High performance Cu2O film/ZnO nanowires self-powered photodetector by electrochemical deposition*
Authors: Guo Deshuang , Li Wei , Wang Dengkui , Meng Bingheng , Fang Dan , Wei Zhipeng
Published: July 2020

Self-powered photodetectors based on nanomaterials have attracted lots of attention for several years due to their various advantages. In this paper, we report a high performance Cu2O/ZnO self-powered photodetector fabricated by using electrochemical deposition. ZnO nanowires arrays grown on indium-tin-oxide glass are immersed in Cu2O film to construct type-II band structure. The Cu2O/ZnO photodetector exhibits a responsivity of 0.288 mA/W at 596 nm without bias. Compared with Cu2O photoconductive detector, the responsivity of the Cu2O/ZnO self-powered photodetector is enhanced by about two times at 2 V bias. It is attributed to the high power conversion efficiency and the efficient separation of the photogenerated electron–hole pairs, which are provided by the heterojunction. The outstanding comprehensive performances make the Cu2O film/ZnO nanowires self-powered photodetector have great potential applications.
Real-time reconstruction of long-lived particles at LHCb using FPGAs
Authors: Cenci Riccardo , Di Luca Andrea , Lazzari Federico , Morello Michael J. , Punzi Giovanni
Published: July 2020

Finding tracks downstream of the magnet at the earliest LHCb trigger level is not part of the baseline plan of the upgrade trigger, on account of the significant CPU time required to execute the search. Many long-lived particles, such as KS
0 and strange baryons, decay after the vertex track detector, so that their reconstruction efficiency is limited. We present a study of the performance of a future innovative real-time tracking system based on FPGAs, developed within a R&D effort in the context of the LHCb Upgrade Ib (LHC Run 4), dedicated to the reconstruction of the particles downstream of the magnet in the forward tracking detector (Scintillating Fibre Tracker), that is capable of processing events at the full LHC collision rate of 30 MHz.
A preliminary study of phases, elemental mapping, and electrical properties on Na2FeSiO4 derived from rice husk silica
Authors: Riyanto A , Sembiring S , Amalia A R , Astika A , Marjunus R
Published: July 2020

This work reports a preliminary investigation about the phase, element mapping, and electrical properties of Na2FeSiO4 prepared from rice husk silica, (FeNO3)3.9H2O, NaOH, and C6H8O7.H2O using the sol-gel method. A sample sintered at 800 °C with a holding time of 10 hours at peak temperature. The phases identification shows that the main phase of Na2FeSiO4 had been formed in the sample accompanied by two impurity phases, i.e., Na2SiO3 and SiO2. Elemental mapping shows that Na, Fe, Si, and O elements are evenly distributed over the entire surface of the sample. The band gap energy value of the sample is relatively small, around 2.58 eV - 2.87 eV. Its electrical conductivity varies depending on frequency, i.e., 6.13×10−5 S/m at 1 Hz and decreases gradually up to 4.27×10−5 S/m at 1000 Hz.