bluuebunny/crossref_metadata_2025 huggingface dataset:
Voids and vacancy-type defects in SiO2/GaN structures probed by monoenergetic positron beams
Authors: Uedono Akira , Ueno Wataru , Yamada Takahiro , Hosoi Takuji , Egger Werner , Koschine Tönjes , Hugenschmidt Christoph , Dickmann Marcel , Watanabe Heiji
Published: February 2020

Voids in SiO2 films deposited on GaN were probed by using monoenergetic positron beams. The films were fabricated on GaN substrates by using plasma-enhanced chemical vapor deposition. The size and density of the voids in the films increased up to an annealing temperature of 800 °C and then decreased at 1000 °C. The observed annealing behaviors of the voids were attributed to the desorption of impurities incorporated during the deposition process and the shrinkage of the Si–O matrix by high-temperature annealing. Vacancy-type defects were introduced into the GaN substrate after 1000 °C annealing in O2 atmosphere due to the diffusion of Ga from the substrate to the SiO2 film. No out-diffusion of Ga into the SiO2 film was observed for the annealing in N2 atmosphere. Thus, the observed out-diffusion of Ga was attributed to the enhanced oxidation of GaN during the annealing in O2 atmosphere. The diffusion of positrons implanted into the GaN substrate toward the SiO2 film was suppressed by annealing, suggesting a decrease in the negative charges in the SiO2 film or near the SiO2/GaN interface.
Synchronization extension using a bistable galloping oscillator for enhanced power generation from concurrent wind and base vibration
Authors: Zhao Liya
Published: February 2020

This Letter proposes a compact bistable galloping oscillator for achieving enhanced power generation from concurrent wind and base vibration. The harvester consists of a D-shaped bluff body attached to a piezoelectric cantilever, with magnetic interaction introduced between the bluff body and a fixed windward prism. Both theoretical analysis and experiment demonstrate the remarkably broadened synchronization bandwidth for concurrent energy harvesting. In the experiment, the voltage steadily increases from 26.6 V at 8.5 Hz to 40.7 V at 12 Hz, achieving a 10 times wider bandwidth than the linear galloping harvester.
Investigation of sound generated by a DC biased rectangular AC current arc in ambient air
Authors: Chen Zhe , Luo Haiyun , Li Handong , Zou Xiaobing , Wang Xinxin
Published: February 2020

In order to investigate the characteristics of arc sound and observe the physical process for the generation of arc sound, the effect of arc parameters including the arc current, arc frequency, and arc length on the arc sound was experimentally investigated. It was found that the power efficiency of sound production varied with the arc length and was relatively low for a short arc. Based on this phenomenon, it was found in the experiment and confirmed in the numerical simulation with a modified physical model that the sound pressure was proportional to dH/dt rather than dP/dt, where H and P are the change rates of internal energy and electric energy of the arc, respectively. In the experiment, the time-resolved arc channel and arc temperature were measured. By correlating the waveform of the arc sound with the time-resolved arc channel and arc temperature, as well as the waveform of arc current and arc power, the physical process for the generation of arc sound is clearly shown.
Temporal microwave ghost imaging using a reconfigurable disordered cavity
Authors: F. Imani Mohammadreza , Smith David R.
Published: February 2020

We propose and experimentally demonstrate the principles for microwave temporal ghost imaging using a disordered cavity loaded with a reconfigurable metasurface. The metasurface behaves as a dynamically reconfigurable surface impedance distribution on one wall of the cavity, effectively perturbing the boundary conditions of the cavity and altering the cavity mode distribution. A microwave signal that passes through the cavity is thus modulated by the changing modal distribution. Assuming that this modulation can happen at a rate faster than the receiver temporal resolution, we show that we can recover the original signal by correlating the pre-recorded response of the modulated cavity with that collected by a slow receiver. This device may find applications in encrypting or compressing microwave signals at the hardware level.
Exploring the landscape of Buckingham potentials for silica by machine learning: Soft vs hard interatomic forcefields
Authors: Liu Han , Li Yipeng , Fu Zipeng , Li Kevin , Bauchy Mathieu
Published: February 2020

Interatomic forcefields for silicate glasses often rely on partial (rather than formal) charges to describe the Coulombic interactions between ions. Such forcefields can be classified as “soft” or “hard” based on the value of the partial charge attributed to Si atoms, wherein softer forcefields rely on smaller partial charges. Here, we use machine learning to efficiently explore the “landscape” of Buckingham forcefields for silica, that is, the evolution of the overall forcefield accuracy as a function of the forcefield parameters. Interestingly, we find that soft and hard forcefields correspond to two distinct, yet competitive local minima in this landscape. By analyzing the structure of the silica configurations predicted by soft and hard forcefields, we show that although soft and hard potentials offer competitive accuracy in describing the short-range order structure, soft potentials feature a higher ability to describe the medium-range order.
Contactless pick-and-place of millimetric objects using inverted near-field acoustic levitation
Authors: Andrade Marco A. B. , Ramos Tiago S. , Adamowski Julio C. , Marzo Asier
Published: February 2020

We model and realize an ultrasonic contactless pick-and-place device capable of picking, self-centering, self-orienting, translating, and releasing flat millimetric objects. The device is an ultrasonic Langevin transducer operating at 21 kHz that radiates into air through a tapered tip. Objects are trapped few micrometers below the tip due to the near-field acoustic levitation phenomenon. We first investigate the conditions to achieve an attractive force on the object depending on its size and the device operating frequency. Second, we use a 3D acoustic model that describes the converging forces and torque that provide the self-centering and self-orienting capabilities. Third, a more advanced Computational Fluid Dynamics model based on the Navier–Stokes equations explains the small gap between the tip and the trapped object. The contactless manipulation capabilities of the device are demonstrated by picking, transporting, and releasing a Surface Mount Device in air. The presented manipulation concept can be an interesting alternative for manipulating delicate objects such as microelectromechanical devices, silicon dies, or micro-optical devices.
Surface chemistry of 2-propanol and O2 mixtures on SnO2(110) studied with ambient-pressure x-ray photoelectron spectroscopy
Authors: Diulus J. Trey , Elzein Radwan , Addou Rafik , Herman Gregory S.
Published: February 2020

Tin dioxide (SnO2) has various applications due to its unique surface and electronic properties. These properties are strongly influenced by Sn oxidation states and associated defect chemistries. Recently, the oxidation of volatile organic compounds (VOCs) into less harmful molecules has been demonstrated using SnO2 catalysts. A common VOC, 2-propanol (isopropyl alcohol, IPA), has been used as a model compound to better understand SnO2 reaction kinetics. We have used ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) to characterize the surface chemistry of IPA and O2 mixtures on stoichiometric, unreconstructed SnO2(110)-(1 × 1) surfaces. AP-XPS experiments were performed for IPA pressures ≤3 mbar, various IPA/O2 ratios, and several reaction temperatures. These measurements allowed us to determine the chemical states of adsorbed species on SnO2(110)-(1 × 1) under numerous experimental conditions. We found that both the IPA/O2 ratio and sample temperature strongly influence reaction chemistries. AP-XPS valence-band spectra indicate that the surface was partially reduced from Sn4+ to Sn2+ during reactions with IPA. In situ mass spectrometry and gas-phase AP-XPS results indicate that the main reaction product was acetone under these conditions. For O2 and IPA mixtures, the reaction kinetics substantially increased and the surface remained solely Sn4+. We believe that O2 replenished surface oxygen vacancies and that SnO2 bridging and in-plane oxygen are likely the active oxygen species. Moreover, addition of O2 to the reaction results in a reduction in formation of acetone and an increase in formation of CO2 and H2O. Based on these studies, we have developed a reaction model that describes the catalytic oxidation of IPA on stoichiometric SnO2(110)-(1 × 1) surfaces.
The passage of a bubble or a drop past an obstruction in a channel
Authors: Zheng Xuebo , Lu Jiacai , Bai Bofeng , Tryggvason Grétar
Published: February 2020

The passage of a fluid particle (bubble or a drop) past an obstruction in a rectangular channel is examined by numerical simulation, focusing on the disruption of the wake and the trajectory of the fluid particle. The flow is laminar, and the wake is initially steady. The obstruction is relatively large compared to the height of the channel. The problem is defined by the capillary number (Ca) and the Reynolds number (Re), the density (ηρ) and viscosity (ημ) ratios, and the relative size of the fluid particle (ηd). Simulations of three-dimensional flows are used to examine several combinations of these parameters. The results show that the motion of a drop is nearly independent of the wake downstream of the obstruction, but bubbles may get temporarily trapped in it. Drops also tend to block the background flow, while bubbles may accelerate it. It is found that a bubble of comparable or smaller size than the constriction can pass through the constriction intact without getting trapped. An increase in Ca and Re leads to bubbles passing through the constriction at a faster speed and move further downstream before being caught by the wake. Simulations of two-dimensional flows for a relatively larger range of Ca and Re are performed to obtain a flow regime diagram. The results show that relatively rigid particles (low Ca) tend to be temporarily trapped in the wake, while more deformable particles (higher Ca) pass without being trapped at lower Reynolds numbers but break up at higher Reynolds numbers. The influence of the obstruction geometry is also examined.
The spectroscopic characterization of interstitial oxygen in bulk silicon: A quantum mechanical simulation
Authors: Gentile Francesco Silvio , Difalco Alessandro , Pascale Fabien , Salustro Simone , Mackrodt William , Dovesi Roberto
Published: February 2020

The vibrational Infrared and Raman spectra of six interstitial oxygen defects in silicon containing a Si—O—Si bridge between adjacent Si atoms are obtained from all-electron B3LYP calculations within a supercell scheme, as embodied in the CRYSTAL code. Two series of defects have been considered, starting from the single interstitial defect, O1. The first consists of four defects, O1,n, in which two O1 defects are separated by (n − 1) Si atoms, up to n = 4. The second consists of four defects, On, in which nO1 defects surround a single Si atom, with n = 1–4, where O4 has the same local nearest neighbor structure as α-quartz. For both series of defects, the equilibrium geometries, charge distributions, and band structures are reported and analyzed. The addition of 1–4 oxygen atoms to the perfect lattice generates 3–12 new vibrational modes, which, as a result of the lighter atomic mass of O with respect to Si, are expected to occur at wavenumbers higher than 521 cm−1, the highest frequency of pristine silicon, thereby generating a unique new Raman spectrum. However, only a small subset of these new modes is found in the spectrum. They appear at 1153 cm−1 (O1), at 1049 cm−1 and 1100 cm−1 (O1,2), at 1108 cm−1 (O1,3), at 1130 cm−1 and 1138 cm−1 (O1,4), and 773 cm−1, 1057 cm−1, and 1086 cm−1 (O4), and can be considered “fingerprints” of the respective defects, as they are sufficiently well separated from each other. Graphical animations indicate the nature and intensity of each of the observed modes which are not overtones or combinations.
Evaluation of critical exponents and magnetocaloric properties in moderate heavy fermion Mn4.5Ni0.5Sn3 alloy
Authors: K Arun , S Swathi , U D Remya , Dzubinska Andrea , Reiffers Marian , R Nagalakshmi
Published: February 2020

Polycrystalline Mn4.5Ni0.5Sn3 alloy has been prepared using arc melting technique. Its crystal structure is found to be of hexagonal Ni2In-type (space group = P63/mmc). The alloy undergoes a ferromagnetic transition of second order at TC = 180 K. Mn4.5Ni0.5Sn3 alloy is a moderate heavy fermion and exhibits bad metallic nature as a consequence of strong impurity scattering. From the critical analysis, the presence of a long range interaction in the alloy is well established as the critical exponents' values are close to the theoretical values of the mean field model. Further magnetocaloric studies reveal a maximum magnetic entropy change of 1.87 J/kg K with a wide working span, ΔT = 86 K, yielding a relative cooling power of 160 J/kg for a field change of 0–5 T.
A self-oscillating electron beam experiment
Authors: Siman-Tov Meytal , Leopold John G. , Krasik Yakov E.
Published: February 2020

A recently proposed scheme to persistently over-inject a vacuum electron diode so that it self-oscillates, releasing a periodic train of electron bunches [Leopold et al., Phys. Plasmas 24, 073116 (2017)] was only partially demonstrated [Siman-Tov et al., 26, 033113 (2019)] because of the presence of hot spots on the dispenser cathode surface. The results obtained utilizing a new dispenser cathode with uniform surface emission, produce self-oscillations close to the expected frequencies.
Au nanoparticles on Fe-modified rutile TiO2(110): Dispersion, thermal stability, and CO adsorption
Authors: Madej Ewa , Korecki Józef , Spiridis Nika
Published: February 2020

Gold clusters on an iron-modified rutile TiO2(110) surface have been characterized via scanning tunneling microscopy and x-ray photoelectron spectroscopy. This study is focused on the impact of submonolayer preadsorbed Fe on the morphologies, surface compositions, and thermal stabilities of bimetallic Au–Fe systems by comparing them to elemental Au and Fe adsorbates. We found that a submonolayer gold adsorbate followed the nucleation mode of the iron precursor, which considerably enhanced the dispersion of nano-gold while improving its thermal stability. Finally, the temperature-programmed CO desorption spectra of Au and Au–Fe nanoparticles on TiO2(110) were compared.
Thermoelectric properties of single-phase full-Heusler alloy Fe2TiSi films with D3-type disordering
Authors: Shimanuki Y. , Kudo K. , Ishibe T. , Masago A. , Yamada S. , Nakamura Y. , Hamaya K.
Published: February 2020

Fe2TiSi has been expected to be one of the high-performance thermoelectric full-Heusler alloys. Here, we experimentally clarify the room-temperature Seebeck coefficient (S) and thermal conductivity (κ) for the Fe2TiSi films. Using a molecular beam epitaxy technique, we demonstrate the high degree of L21-ordering and the homogeneous single-phase structure in the Fe2TiSi films. We find that the intrinsic conduction carriers of the Fe2TiSi films are holes and impurity-induced carrier scattering is indicated, derived from weak magnetic moments due to the presence of D03-type (Fe ⇔ Ti) structural disorder in the Fe2TiSi film. From reliable measurements for thin films, the values of S and κ are estimated to be 101 μV/K and 5.6 W/(m K), respectively, at room temperature. This study will open a new way for full-Heusler alloy thermoelectric materials other than those in Fe2VAl systems.
Determination of dielectric axes and transition moment directions in β-Ga2O3 from the polarization dependence of vibrational spectra
Authors: Portoff Amanda , Venzie Andrew , Stavola Michael , Fowler W. Beall , Pearton Stephen J.
Published: February 2020

β-Ga2O3 is a promising ultrawide bandgap semiconductor for high power and extreme environment applications. The dominant O—H center in Ga2O3 has been assigned to a Ga(1) vacancy–2H (VGa(1)-2H) complex. An analysis of the polarization dependence of the vibrational absorption of the VGa(1)-2D center in monoclinic β-Ga2O3 provides a unique strategy for the determination of both the orientation of the principal dielectric axes in the near infrared and the direction of the vibrational transition moment of the defect.
Rotational electromagnetic energy harvester for human motion application at low frequency
Authors: Zhang Yulong , Luo Anxin , Wang Yifan , Dai Xiangtian , Lu Yan , Wang Fei
Published: February 2020

A rotational electromagnetic energy harvester is designed to collect the mechanical energy of human motion at a low frequency. Linear motion can be converted to high speed rotation with an inertial system, which is mainly composed of a twist driving structure and a ratchet-clutch structure. When the twist rod is compressed by a footstep, the ratchet can keep rotating for about 20 s inertially, and an overall energy of 85.2 mJ can be harvested. The peak power output can reach 32.2 mW and a root mean square power of 7.7 mW is achieved. The maximum speed of the ratchet would be as high as 3700 revolutions per minute. When driven by the human footstep at a frequency of 1 Hz, an electronic hygrothermograph and 70 light-emitting diodes (LEDs) could be easily powered, which demonstrates the promising application of self-powered microelectronic devices.
Spatially varying colloidal phase behavior on multi-dimensional energy landscapes
Authors: Zhang Jianli , Zhang Yuanxing , Bevan Michael A.
Published: February 2020

A method is reported to determine equilibrium concentration profiles and local phase behavior of colloids on multi-dimensional energy landscapes. A general expression is derived based on local particle concentration and osmotic pressure differences that are balanced by forces on colloids due to energy landscape gradients. This analysis is applied to colloidal particles in high frequency AC electric fields within octupolar electrodes, where the energy landscape can be shaped in two dimensions. These results are also directly applicable to any particles having induced dipoles in spatially non-uniform electromagnetic fields. Predictions based on modeling colloids with an effective hard disk equation of state indicate inhomogeneous solid and fluid states coexisting on different shaped energy landscapes including multiple minima. Model predictions show excellent agreement with time-averaged Brownian dynamic simulations at equilibrium. Findings demonstrate a general approach to understand colloidal phase behavior on energy landscapes due to external fields, which could enable control of colloidal microstructures on morphing energy landscapes and the inverse design of fields to assemble hierarchically structured colloidal materials.
Features of the arc binding region structure on the surface of the thoriated cathode in atmospheric pressured argon
Authors: Sargsyan M. A. , Tereshonok D. V. , Valyano G. E. , Scherbakov V. V. , Konovalov P. A. , Gadzhiev M. Kh.
Published: February 2020

The parameters of a non-pulsed dc arc discharge of atmospheric pressure in argon were experimentally studied, and the chemical composition of the cathode surface in the arc binding zone was studied. The measurements were performed for thoriated tungsten cathodes (W-2% ThO2) for currents of 200 and 300 A. During the operation of the plasma torch, the temperature and electron concentration in the positive column and the surface temperature of the cathode were measured. A computational and theoretical analysis was performed on the distribution of current density and electric field strength in the arc binding zone. As a result, three fundamentally different zones of the arc binding area were identified, and their size and chemical composition were determined.
Combination of imaging techniques allows for visualization of polymer curing processes
Authors: Bandari Anashe
Published: February 2020

Researchers developed a method to monitor the curing behavior at depths within a polymer specimen.
Drivers of cyanobacterial blooms in lakes and reservoirs in Jinan City, China
Authors: Zhao C. S. , Pan X. , Yang S. T. , Wang X. L. , Liu X. J. , Sun Y. , Yang Y. , Pan T. L.
Published: February 2020

Cyanobacterial blooms are a serious issue and frequently occur in lakes and reservoirs. Understanding how topography and human activities affect cyanobacterial dominance and blooms can greatly enhance the success of restoration projects to reduce blooms. Therefore, in this study the dominant species of cyanobacteria were determined by calculating the break point of the cumulative dominance curve for multiple sites in Jinan, China. In addition, the key drivers affecting the dominant cyanobacteria species were identified by canonical correspondence analysis and correlations between topography, human activities and the key drivers of the dominant cyanobacteria were investigated using random forests analysis. Merismopedia glauca, Merismopedia tenuissima, Microcystis aeruginosa, Oscillatoria tenuis, Phormidium tenus and Raphidiopsis sinensia were determined to be the dominant species. The key drivers of cyanobacterial bloom development were total phosphorus (TP), ammonium nitrogen (NH3-N), water temperature and total hardness. Topography and human activities were highly correlated with the key driving factors. The higher the altitude, the greater the effect of water temperature on the cyanobacteria community. In the area where sewage irrigation was present and a large amount of chemical fertiliser was used, total hardness had a greater effect on the cyanobacteria community. In areas where the population was more concentrated, TP and NH3-N had greater effects on the cyanobacteria community.
Glioblastomas exploit truncated O
-
linked glycans for local and distant immune modulation via the macrophage galactose-type lectin
Authors: Dusoswa Sophie A. , Verhoeff Jan , Abels Erik , Méndez-Huergo Santiago P. , Croci Diego O. , Kuijper Lisan H. , de Miguel Elena , Wouters Valerie M. C. J. , Best Myron G. , Rodriguez Ernesto , Cornelissen Lenneke A. M. , van Vliet Sandra J. , Wesseling Pieter , Breakefield Xandra O. , Noske David P. , Würdinger Thomas , Broekman Marike L. D. , Rabinovich Gabriel A. , van Kooyk Yvette , Garcia-Vallejo Juan J.
Published: February 2020

Glioblastoma is the most aggressive brain malignancy, for which immunotherapy has failed to prolong survival. Glioblastoma-associated immune infiltrates are dominated by tumor-associated macrophages and microglia (TAMs), which are key mediators of immune suppression and resistance to immunotherapy. We and others demonstrated aberrant expression of glycans in different cancer types. These tumor-associated glycans trigger inhibitory signaling in TAMs through glycan-binding receptors. We investigated the glioblastoma glycocalyx as a tumor-intrinsic immune suppressor. We detected increased expression of both tumor-associated truncated O-linked glycans and their receptor, macrophage galactose-type lectin (MGL), on CD163
+
TAMs in glioblastoma patient-derived tumor tissues. In an immunocompetent orthotopic glioma mouse model overexpressing truncated O-linked glycans (MGL ligands), high-dimensional mass cytometry revealed a wide heterogeneity of infiltrating myeloid cells with increased infiltration of PD-L1
+
TAMs as well as distant alterations in the bone marrow (BM). Our results demonstrate that glioblastomas exploit cell surface O-linked glycans for local and distant immune modulation.
Conformational spread and dynamics in allostery of NMDA receptors
Authors: Durham Ryan J. , Paudyal Nabina , Carrillo Elisa , Bhatia Nidhi Kaur , Maclean David M. , Berka Vladimir , Dolino Drew M. , Gorfe Alemayehu A. , Jayaraman Vasanthi
Published: February 2020

Significance

NMDA receptors are the main excitatory receptors in the mammalian central nervous system. They require the binding of both glutamate and glycine for the activation of the protein. However, the binding of one agonist lowers the affinity of the second. The mechanism and physiological significance of this negative cooperativity between the two agonists is currently unknown. Using single molecule FRET and MD simulations we show that binding of one agonist destabilizes the second agonist-binding domain, making it less favorable to bind the second agonist, thus leading to lower affinity. Additionally, there is minimal effect on the transmembrane segments in the presence of a single agonist thus ensuring that the protein is activated only when bound to both agonists.
Functional connectivity predicts changes in attention observed across minutes, days, and months
Authors: Rosenberg Monica D. , Scheinost Dustin , Greene Abigail S. , Avery Emily W. , Kwon Young Hye , Finn Emily S. , Ramani Ramachandran , Qiu Maolin , Constable R. Todd , Chun Marvin M.
Published: February 2020

The ability to sustain attention differs across people and changes within a single person over time. Although recent work has demonstrated that patterns of functional brain connectivity predict individual differences in sustained attention, whether these same patterns capture fluctuations in attention within individuals remains unclear. Here, across five independent studies, we demonstrate that the sustained attention connectome-based predictive model (CPM), a validated model of sustained attention function, generalizes to predict attentional state from data collected across minutes, days, weeks, and months. Furthermore, the sustained attention CPM is sensitive to within-subject state changes induced by propofol as well as sevoflurane, such that individuals show functional connectivity signatures of stronger attentional states when awake than when under deep sedation and light anesthesia. Together, these results demonstrate that fluctuations in attentional state reflect variability in the same functional connectivity patterns that predict individual differences in sustained attention.
Splice switching an oncogenic ratio of SmgGDS isoforms as a strategy to diminish malignancy
Authors: Brandt Anthony C. , McNally Lisa , Lorimer Ellen L. , Unger Bethany , Koehn Olivia J. , Suazo Kiall F. , Rein Lisa , Szabo Aniko , Tsaih Shirng-Wern , Distefano Mark D. , Flister Michael J. , Rigo Frank , McNally Mark T. , Williams Carol L.
Published: February 2020

Significance

Oncogenic signaling by small GTPases enhances malignant phenotypes in both breast and lung cancer. The SmgGDS splice variant isoforms SmgGDS-607 and SmgGDS-558 activate oncogenic small GTPases by promoting their prenylation. We report that a pathologic ratio of SmgGDS splice variants is expressed in cancer cells and is associated with decreased survival of breast cancer patients. We developed a splice-switching oligonucleotide (SSO) to target this oncogenic SmgGDS isoform ratio. This SSO suppresses prenylation of small GTPases, induces apoptotic cell death of breast and lung cancer cells, and diminishes tumorigenesis in an aggressive mouse model of breast cancer. These results define a strategy to suppress the prenylation of small GTPases and diminish malignancy by modulating SmgGDS splicing.
Np
4
A alarmones function in bacteria as precursors to RNA caps
Authors: Luciano Daniel J. , Belasco Joel G.
Published: February 2020

Significance

Since their discovery more than 50 years ago, dinucleoside tetraphosphates have been found in all realms of life, at levels correlated with a variety of intriguing physiological changes. However, their molecular mechanism of action has largely remained an enigma. Here we present evidence that in bacteria they are incorporated as an alternative chain-initiating nucleotide during transcription by RNA polymerase, generating RNAs that bear a novel nucleoside tetraphosphate cap at the 5′ end. Their assimilation into nascent transcripts is remarkably efficient, up to nine times the efficiency of nucleoside triphosphates. These and other findings suggest that dinucleoside tetraphosphates influence bacterial physiology not by signaling via a hypothetical receptor, but rather by modifying cellular RNAs and impacting their function.
Development of an antibody cocktail for treatment of Sudan virus infection
Authors: Herbert Andrew S. , Froude Jeffery W. , Ortiz Ramon A. , Kuehne Ana I. , Dorosky Danielle E. , Bakken Russell R. , Zak Samantha E. , Josleyn Nicole M. , Musiychuk Konstantin , Jones R. Mark , Green Brian , Streatfield Stephen J. , Wec Anna Z. , Bohorova Natasha , Bohorov Ognian , Kim Do H. , Pauly Michael H. , Velasco Jesus , Whaley Kevin J. , Stonier Spencer W. , Bornholdt Zachary A. , Chandran Kartik , Zeitlin Larry , Sampey Darryl , Yusibov Vidadi , Dye John M.
Published: February 2020

Significance

Ebolaviruses pose a significant threat to the global community, particularly in areas of equatorial and West Africa. While Ebola virus has caused the greatest number of human cases, Sudan virus is responsible for numerous outbreaks with equally lethal consequences. Antibody-based immunotherapies against ebolaviruses have gained prominence in recent years, resulting in the development of several Ebola virus-specific antibody cocktails, yet no Sudan virus-specific cocktails exist. In collaboration with industry partners, we generated a library of human chimeric monoclonal antibodies (mAbs) specific for the glycoprotein of Sudan virus. Through a series of in vitro assays and rodent efficacy studies, we down-selected a lead mAb cocktail that demonstrated protective efficacy in a nonhuman primate model of Sudan virus infection.
Energy dissipation bounds for autonomous thermodynamic cycles
Authors: Bryant Samuel J. , Machta Benjamin B.
Published: February 2020

Significance

The second law states that on average, it is impossible for a process to reduce the entropy of the universe. Recent progress has strengthened this inequality by quantifying the dissipation associated with various scenarios. Moving a thermodynamic system dissipates energy because the system is pushed out of equilibrium, quantified by friction. Also, precise control of a degree of freedom requires dissipation due to broken time-reversal symmetry. When considered alone, these two bounds can be made arbitrarily small by either moving slowly or moving imprecisely. However, here we show that for a self-contained thermodynamic process, which must incur both of these costs, there is a lower energetic bound which cannot be made arbitrarily small, even when all changes happen infinitely slowly.
Unique subsite specificity and potential natural function of a chitosan deacetylase from the human pathogen
Cryptococcus neoformans
Authors: Hembach Lea , Bonin Martin , Gorzelanny Christian , Moerschbacher Bruno M.
Published: February 2020

Significance

The opportunistic fungal pathogen
Cryptococcus neoformans
is a major threat to immunocompromised patients. Most fungal cell walls expose chitin, which is recognized by the human immune system, but
C. neoformans
is one of the few species that instead exposes chitosan, the deacetylated form of chitin. Chitosan is produced by chitin synthases and chitin deacetylases, the latter acting on chitin as a substrate. Here we describe the detailed functional analysis of CnCda4, a chitin deacetylase with unusual subsite specificity resulting in a preference for chitosan rather than chitin. By testing the effect of CnCda4 deacetylation products on human peripheral blood-derived macrophages, we show that the enzyme probably helps the pathogen to evade the host immune system by further deacetylating exposed chitosans.
Facilitative and synergistic interactions between fungal and plant viruses
Authors: Bian Ruiling , Andika Ida Bagus , Pang Tianxing , Lian Ziqian , Wei Shuang , Niu Erbo , Wu Yunfeng , Kondo Hideki , Liu Xili , Sun Liying
Published: February 2020

Significance

Unlike other eukaryotic viruses, fungal viruses generally lack an extracellular phase in their life cycle. It thus remains unclear whether fungal viruses can spread beyond their native hosts. Herein, we investigated the infectivity of a fungal virus, Cryphonectria hypovirus 1 (CHV1) in
Nicotiana tabacum
plants. CHV1 is able to systemically infect plants after mechanical coinoculations with plant viruses such as tobacco mosaic virus (TMV) or when inoculated to transgenic plants expressing the TMV movement protein. In the fungal inoculation experiment, we demonstrated that plant virus infections in plants enable horizontal transfer of CHV1 from fungi to plants and to other heterologous fungal species. Hence, our results reveal a facilitative effect of plant viruses in spreading fungal viruses.
Spatiotemporal dynamic monitoring of fatty acid–receptor interaction on single living cells by multiplexed Raman imaging
Authors: Zhang Wei , Lin Fangjun , Liu Yan , Zhang Han , Gilbertson Timothy A. , Zhou Anhong
Published: February 2020

Numerous fatty acid receptors have proven to play critical roles in normal physiology. Interactions among these receptor types and their subsequent membrane trafficking has not been fully elucidated, due in part to the lack of efficient tools to track these cellular events. In this study, we fabricated the surface-enhanced Raman scattering (SERS)-based molecular sensors for detection of two putative fatty acid receptors, G protein-coupled receptor 120 (GPR120) and cluster of differentiation 36 (CD36), in a spatiotemporal manner in single cells. These SERS probes allowed multiplex detection of GPR120 and CD36, as well as a peak that represented the cell. This multiplexed sensing system enabled the real-time monitoring of fatty acid-induced receptor activation and dynamic distributions on the cell surface, as well as tracking of the receptors’ internalization processes on the addition of fatty acid. Increased SERS signals were seen in engineered HEK293 cells with higher fatty acid concentrations, while decreased responses were found in cell line TBDc1, suggesting that the endocytic process requires innate cellular components. SERS mapping results confirm that GPR120 is the primary receptor and may work synergistically with CD36 in sensing polyunsaturated fatty acids and promoting Ca
2+
mobilization, further activating the process of fatty acid uptake. The ability to detect receptors’ locations and monitor fatty acid-induced receptor redistribution demonstrates the specificity and potential of our multiplexed SERS imaging platform in the study of fatty acid–receptor interactions and might provide functional information for better understanding their roles in fat intake and development of fat-induced obesity.
NAD deficiency due to environmental factors or gene–environment interactions causes congenital malformations and miscarriage in mice
Authors: Cuny Hartmut , Rapadas Melissa , Gereis Jessica , Martin Ella M. M. A. , Kirk Rosemary B. , Shi Hongjun , Dunwoodie Sally L.
Published: February 2020

Significance

Causes for congenital malformations and miscarriages can be genetic, environmental, or a combination of multiple factors; however, in most cases, the underlying reasons are unknown. This study shows that a dietary undersupply of tryptophan and vitamin B3, the metabolic precursors of nicotinamide adenine dinucleotide (NAD), during pregnancy is a cause for frequent multiple birth defects and miscarriages in wild-type mice. When the maternal malnutrition coincided with a genetic variant that impaired NAD synthesis or low oxygen levels as an environmental factor, embryos were more severely affected. Our findings in mice suggest NAD deficiency, due to environmental factors or gene–environment interactions, as a possible cause of congenital malformations in human cases in which no causative gene defect is present.
Kv2.1 channels play opposing roles in regulating membrane potential, Ca
2+
channel function, and myogenic tone in arterial smooth muscle
Authors: O’Dwyer Samantha C. , Palacio Stephanie , Matsumoto Collin , Guarina Laura , Klug Nicholas R. , Tajada Sendoa , Rosati Barbara , McKinnon David , Trimmer James S. , Santana L. Fernando
Published: February 2020

Significance

Our data challenge the generally accepted view that Kv2.1 proteins regulate arterial smooth muscle function by regulating their membrane potential. Rather, we discovered that Kv2.1 plays both conductive and structural roles with opposing functional consequences on arterial myocytes, with the former predominating in males, the latter in females. Opening of Kv2.1 channels opposes vasoconstriction by inducing membrane hyperpolarization. In addition to this conductive function, Kv2.1 promotes the structural clustering of Ca
V
1.2 channels, thereby enhancing Ca
2+
influx and inducing vasoconstriction. These two functions are highlighted by differences in the regulation of membrane potential, intracellular Ca
2+
, and myogenic tone between males and females. Our data suggest that these disparities derive from sex-specific variations in Kv2.1 expression levels in male versus female myocytes.
Measuring the effectiveness of high-performance Co-Optima biofuels on suppressing soot formation at high temperature
Authors: Barak Samuel , Rahman Ramees K. , Neupane Sneha , Ninnemann Erik , Arafin Farhan , Laich Andrew , Terracciano Anthony C. , Vasu Subith S.
Published: February 2020

Significance

Biofuels are renewables that are blended with conventional fuels because of similarities in the composition and other physical and chemical properties. Over the last 10 y, researchers have examined a variety of biofuels that could replace fossil fuels; however, most have fallen into a few categories of chemical classes. Even though biofuels are a promising renewable alternative to conventional petroleum fuels that could lower greenhouse gas emissions, the products that are most efficiently produced from biomass may not have well-characterized combustion properties as they represent a wide range of chemical structures, which have different emission behavior. The current work provides a comprehensive evaluation of the sooting tendencies of high-performance biofuels selected by the US Department of Energy.
The Quest for Argumentative Equivalence
Authors: Brambilla Emanuele
Published: February 2020

What are the implications of strategic manoeuvring for the activity of the simultaneous interpreter? This is the main question addressed in The Quest for Argumentative Equivalence. Based on the analysis of a multilingual comparable corpus named ARGO, the book investigates political argumentation with an eye to its reformulation by interpreters. After reporting and discussing a series of case studies illustrating interpreters’ problems in the political context, the study reconstructs the prototypical argumentative patterns used by Obama, Cameron, Sarkozy and Hollande not only in a hermeneutical perspective, but also considering interpreters’ need to reproduce them into a foreign language. Situated at the intersection of Argumentation Theory and Interpreting Studies, the book provides a contribution to the descriptive study of political argumentation, highlighting the presence of interpreters as a key contextual variable in political communication and deepening the study of the interlinguistic and translational implications of the act of arguing.
Narrative metaphors in Polish perfumery discourse
Authors: Zawisławska Magdalena
Published: February 2020

The Polish perfumery discourse is permeated with various kinds of metaphors, starting with lexicalized metaphorical terms, e.g.,nuta“note”, to creative, extended, and elaborated metaphors, e.g.,Intensywnie doprawiony przedpokój prowadzi do cytrusowegosalonu, który jak dla mnie mógłby zajmować trochę mniej miejsca, bo najbardziej wartościowa jest kuchnia – serce domu!“Intensively flavored entrance hall leads to the citrus salon, which for me could be smaller because the most valuable is the kitchen – the heart of a home!” This paper concentrates on a specific type of verbal metaphor, used quite often in the Polish perfumery discourse, callednarrative metaphor. Such narrative metaphors can encompass extensive fragments of a discourse or even a whole text. This study describes the triggers of narrative metaphors in perfumery discourse and emphasizes the importance of reference in such metaphor analysis.
Cognitive principles underlying predicational metonymy
Authors: Komatsubara Tetsuta
Published: February 2020

Metonymy of a predicate, in which the source event implies the target event, is called predicational
metonymy. This paper focused on a Japanese productive predicational metonymy, action for causation, and
described its linguistic preference in terms of aspectual construal based on a corpus-driven quantitative investigation. The
results revealed that an event that is bounded and durative is preferred as the metonymic vehicle in action for causation
metonymy. The two cognitive principles, bounded over unbounded and durative over punctual, were proposed to
explain the linguistic preference. It was suggested that the two principles can be subsumed under the fundamental cognitive
principle of good Gestalt over poor Gestalt, and that this general principle governs metonymic
preference of both predicates and nominal phrases.
An instrument for monitoring stump oedema and shrinkage in amputees
Authors: Fernie G. R. , Holliday P. J. , Lobb R. J.
Published: February 2020

A new system for measuring the cross-sectional area profiles of amputation stumps and whole limbs has been designed at the Amputee Research Centre. The instrument consists of a cylindrical tank supported on an elevator. The tank is raised to the height of the amputation stump and filled with water. A graph of the cross-sectional area profile of the amputation stump is generated by a mini-computer as the elevator descends. The cross-sectional area (A) is calculated from the expression:

where Hw = height of water in the tank

This paper describes the instrument, which may find application in many other areas where there is a need to study shape.
The value of flexor hinge hand splints
Authors: Nichols P. J. R. , Peach S. L. , Haworth R. J. , Ennis J.
Published: February 2020

Functional hand splints have been in use in a number of spinal injury units in the USA since the early 1950s. The splints are designed to provide a pinch-grip either by harnessing wrist dorsiflexion or by external power. Such devices are little used in the United Kingdom.

This paper describes the results of late provision of 62 such splints in a Disabled Living Unit. A proportion of tetraplegic patients found such splints of considerable functional value.

It is estimated that some 30–60 patients each year would benefit from them if appropriate facilities for early fitting were available.
Diffusion of Brazil’s food policies in international organisations: assessing the processes of knowledge framing
Authors: Milhorance Carolina
Published: February 2020

This article focuses on the political dynamics shaping policy agendas and prescriptions in international organisations (IOs). It elucidates the interactions of Brazil’s state and non-state actors with international bureaucrats, and their role in framing the strategy and recommendations promoted by the UN Food and Agriculture Organization and Portuguese-speaking Community of Countries regarding the challenge of tackling food insecurity. The research builds on semi-structured interviews and a significant number of institutional documents, and combines constructivist international relations theory and sociological approaches to policy transfer/diffusion to explore the circulatory processes of policymaking. Aside from enhancing understanding of the micro-dynamics of framing and diffusion of policy ideas and prescriptions in IOs, the article provides information on the dissemination of policy solutions from the global south towards IOs and subsequently, to other developing countries.
Design, fabrication and modeling analysis of a spiral support structure with superelastic Ni-Ti shape memory alloy for continuum robot
Authors: Tian Jiawen , Wang Tianmiao , Fang Xi , Shi Zhenyun
Published: February 2020

In order to improve the working ability of continuum robots in confined space, a novel central support structure with the spiral cutting pattern is proposed in this paper. The spiral hollow scheme was selected through analysing different cutting patterns of the thin-walled superelastic Ni-Ti shape memory alloy (SMA) tube. Then the laser cutting process and heat treatment for fabricating the structure were analysed. The analysis results of their impact on the material characteristics proves that the laser cutting and heat treatment ensure the performance of the material. The single-segment and multi-segment prototypes both showed prospective motion ability in the flexural rigidity and continuous deformation tests respectively. Then the flexural rigidity model of the spiral structure was proposed, which was proved effective by comparing the model simulation and finite element analysis results. Furthermore, the central support structures with different flexural rigidities can be customized, which has broad application prospects in continuum robots.
Sixteen Open Clusters Discovered with Sample-based Clustering Search of Gaia DR2
Authors: Hao ChaoJie , Xu Ye , Wu ZhenYu , He ZhiHong , Bian ShuaiBo
Published: February 2020

Accurate astrometric parameters and photometric data in three bands for more than 1.3 billion sources (mainly stars) were made available in the recent Gaia Data Release 2, allowing us to find new open clusters in the milky Way. We propose a novel sample-based clustering search method with high spatial resolution to search for open clusters (OCs). We used the proposed method to find 16 new OC candidates. Their astrometric parameters are presented, including age, etc.
Historical trends in the amount and structure of organic carbon stocks in natural and managed ecosystems in European Russia
Authors: Chernova O V , Ryzhova I M , Podvezennaya M A
Published: February 2020

Contemporary (corresponding to the modern state of ecosystems and land use) and prehistoric (for hypothetic intact natural ecosystems similar to modern virgin ecosystems) stocks of organic carbon were assessed for model regions of southern taiga, forest-steppe and steppe in European Russia. The comparison of these stocks enabled an assessment of the integral result of the multidirectional changes in land use that occurred in the studied regions over the historical period. The carbon stocks were determined using a unified cartographic basis, data on taxonomy and texture of soil units, modern land use types and the type and age structure of reconstructed and contemporary vegetation. The results obtained indicate that the modern carbon pool has reduced by 24% compared to the potential prehistoric one in the Kostroma Region and Rostov Region (southern taiga and steppe zones, respectively) and by 37% in the Kursk Region (forest-steppe zone). It was also demonstrated that the contribution of soil to the total organic carbon stock increases southwards, from southern taiga to dry steppe, from 51 to 95% during the prehistoric period and from 62 to 96% currently. The study results show that forestry and agriculture increase the contribution of soil to maintaining the region’s carbon budget.