bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear dynamics of double-layer unstable interfaces with non-uniform velocity shear
Authors: Matsuoka Chihiro
Published: October 2020

The interaction of double-layer density stratified interfaces with initial non-uniform velocity shear is investigated theoretically and numerically, taking the incompressible Richtmyer–Meshkov instability as an example. The linear analysis for providing the initial conditions in numerical calculations is performed, and some numerical examples of vortex double layers are presented using the vortex sheet model. We show that the density stratifications (Atwood numbers), the initial distance between two interfaces, and the distribution of the initial velocity shear determine the evolution of vortex double layers. When the Atwood numbers are large, the deformation of interfaces is small, and the distance between the two interfaces is almost unchanged. On the other hand, when the Atwood numbers are small and the initial distance between two interfaces is sufficiently close (less than or equal to the half of the wavelength of the initial disturbance), the two interfaces get closer to each other and merge at the last computed stage due to the incompressibility. We confirm this theoretically expected fact numerically.
Factors determining formation efficiencies of one-electron-reduced species of redox photosensitizers
Authors: Ozawa Kyohei , Tamaki Yusuke , Kamogawa Kei , Koike Kazuhide , Ishitani Osamu
Published: October 2020

Improvement in the photochemical formation efficiency of one-electron-reduced species (OERS) of a photoredox photosensitizer (a redox catalyst) is directly linked to the improvement in efficiencies of the various photocatalytic reactions themselves. We investigated the primary processes of a photochemical reduction of two series [Ru(diimine)3]2+ and [Os(diimine)3]2+ as frequently used redox photosensitizers (PS2+), by 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as a typical reductant in detail using steady-irradiation and time-resolved spectroscopies. The rate constants of all elementary processes of the photochemical reduction of PS2+ by BIH to give the free PS•+ were obtained or estimated. The most important process for determining the formation efficiency of the free PS•+ was the escape yield from the solvated ion pair [PS•+–BIH•+], which was strongly dependent on both the central metal ion and the ligands. In cases with the same central metal ion, the system with larger −ΔGbet, which is the free energy change in the back-electron transfer from the OERS of PS•+ to BIH•+, tended to lower the escape yield of the free OERS of PS2+. On the other hand, different central metal ions drastically affected the escape yield even in cases with similar −ΔGbet; the escape yield in the case of RuH2+ (−ΔGbet = 1.68 eV) was 5–11 times higher compared to those of OsH2+ (−ΔGbet = 1.60 eV) and OsMe2+ (−ΔGbet = 1.71 eV). The back-electron transfer process from the free PS•+ to the free BIH•+ could not compete against the further reaction of the free BIH•+, which is the deprotonation process giving BI•, in DMA for all examples. The produced BI• gave one electron to PS2+ in the ground state to give another PS•+, quantitatively. Based on these findings and investigations, it is clarified that the photochemical formation efficiency of the free PS•+ should be affected not only by −ΔGbet but also by the heavy-atom effect of the central metal ion, and/or the oxidation power of the excited PS2+, which should determine the distance between the excited PS and BIH at the moment of the electron transfer.
Ground and excited state first-order properties in many-body expanded full configuration interaction theory
Authors: Eriksen Janus J. , Gauss Jürgen
Published: October 2020

The recently proposed many-body expanded full configuration interaction (MBE-FCI) method is extended to excited states and static first-order properties different from total, ground state correlation energies. Results are presented for excitation energies and (transition) dipole moments of two prototypical, heteronuclear diatomics—LiH and MgO—in augmented correlation consistent basis sets of up to quadruple-ζ quality. Given that MBE-FCI properties are evaluated without recourse to a sampled wave function and the storage of corresponding reduced density matrices, the memory overhead associated with the calculation of general first-order properties only scales with the dimension of the desired property. In combination with the demonstrated performance, the present developments are bound to admit a wide range of future applications by means of many-body expanded treatments of electron correlation.
Vibrational spectroscopy of shock compressed condensed phase nitrous oxide: Frequency shifts in the ν1 mode
Authors: Moore David S. , Leiding Jeffery A.
Published: October 2020

Over many years, we have published vibrational spectra of molecular materials at extreme pressure and temperature obtained using shock compression and coherent Raman spectroscopy methods. For diatomic molecules, we were able to extract vibrational temperatures from the intensities of spectrally resolved vibrational hot bands. Larger molecules in the condensed phase suffer band broadening effects that obscure the vibrational hot bands as the anharmonicities are typically smaller than the widths of the bands. This inability to resolve the hot bands inhibits the extraction of vibrational temperature and the measurement of the vibrational frequency of the fundamental. Here, we use a hot band model based on gas-phase anharmonic coupling coefficients to fit coherent anti-Stokes Raman spectra of the ν1 vibrational mode of shock compressed condensed phase N2O with shock pressures and temperatures estimated from literature equations of state and compare to fits from a model using a single Gaussian peak. We report the resulting vibrational frequency shifts with shock pressure.
Numerical simulation of thermal-solutal Marangoni convection in a shallow rectangular cavity with mutually perpendicular temperature and concentration gradients
Authors: Zhang Jiangao , Sekimoto Atsushi , Okano Yasunori , Dost Sadik
Published: October 2020

A series of three-dimensional numerical simulations have been carried out to examine the characteristics of thermal-solutal Marangoni convection in a rectangular cavity that is subjected to mutually perpendicular temperature and concentration gradients. In the simulations, the thermal Marangoni number MaT is selected as 0, 1, 3, and 7 × 104, but the solutal Marangoni number MaC is varied in order to be able to investigate the complex flow patterns and flow transitions. Results show that the flow is steady at relatively small MaC. Then, at this MaC value, we observe three types of steady flows as MaT increases, namely, a longitudinal surface flow, an oblique stripe flow, and a lateral surface flow. When MaC exceeds a critical value, the stability of the Marangoni flow is destroyed, and a three-dimensional oscillatory flow appears. For the oscillatory flow, the wave patterns of temperature and concentration fluctuations are highly dependent on the coupling of the thermal and solutal Marangoni effect. Two different propagation directions of wave patterns coexist on the free surface when the contributions of thermal and solutal flows are in the same order (i.e., MaC is approximately equal to MaT). In addition, a sudden drop in the wave frequency and a backward transition phenomenon from chaotic to oscillatory are also observed. For all the cases of the thermal Marangoni numbers, thermal-solutal Marangoni convection becomes chaotic at higher MaC values. The present study would provide more physical insights into industrial processes such as painting and drying.
Seed germination response of a potential rangeland weed Psilocaulon granulicaule to selected environmental conditions
Authors: Ranaweera Rekha , Weller Sandra L. , Florentine Singarayer K.
Published: October 2020

Studies show that just over 620 non-native naturalised plant species have been recorded within the Australian rangelands, some of which have a capacity to cause significant impacts on rangeland flora and grazing activity. Although Psilocaulon granulicaule (Haw.), Schwantes is listed as a highly invasive environmental weed species, there has been no previous research into its seed ecology. Therefore, this study was conducted to investigate the effects of temperature, light, pH, water stress, heat-shock, and salinity on the germination of P. granulicaule. In this study, four temperature regimes covering four different day and night temperature variations (17–7°C, 25–15°C, 30–25°C and 40–30°C) and two light regimes (12-h light–12-h dark, 24-h dark) were investigated. The effects of pH, water stress, heat-shock and salinity were investigated, using pH buffers, polyethylene glycol solutions, three heat shock events under four temperatures and a range of NaCl solutions. These tests were conducted under the identified optimum temperature range (25/15°C) and light regime for seed germination. The results showed that both temperature and photoperiod significantly influenced the germination rate, with 94.2% germination in the 25–15°C range under a 12-h light-12-h dark regime. Higher temperatures (30–40°C) reduced seed germination to <58% germination in both light regimes (57.5%, 12-h light-12-h dark; 54.17%, 24-h dark). The highest germination rates were observed in low pH solutions, high moisture levels, low heat-shocks and low salinity. The study showed that this species is sensitive to environmental factors such as temperature, light, pH, moisture, heat shock and salinity, suggesting that these factors can be used as critical indicators to guide effective management practices to address this weed problem. Given that seeds are sensitive to radiant heat, burning could be used as a tool to effectively manage this species.
Ammonium metabolism in Selaginella bryopteris in response to dehydration-rehydration and characterisation of desiccation tolerant, thermostable, cytosolic glutamine synthetase from plant
Authors: Singh Kamal K. , Saha Shyamaprasad , Kadiravana Ram C. , Mazumdar Deepika , Rai Vijeta , Ghosh Shilpi
Published: October 2020

Water deficit (WD) has adverse effects on plant growth, and acclimation requires responses allowing primary metabolism to continue. Resurrection plants can serve as model system to gain insight into metabolic regulation during WD. We herein report the response of a resurrection lycophyte, Selaginella bryopteris, to dehydration-rehydration cycle with emphasis on ammonium metabolism. Dehydration of S. bryopteris fronds resulted in decrease of total protein and increase of free ammonium levels and the effect was reversed on rehydration. The proline content increased twice after 24 h of dehydration, which again recovered to background levels comparable to that at full turgor state. The specific activity of glutamine synthetase (GS) didn’t change significantly till 6 h and then declined by 21% after 24 h of dehydration, whereas specific activities of glutamate synthase (GOGAT) and aminating glutamate dehydrogenase (GDH) were enhanced significantly during dehydration. The deaminating activity of GDH also increased during dehydration albeit at a slower rate. Immunoblot analysis indicated overexpression of GS and GDH polypeptides during dehydration and their levels declined on rehydration. The results suggested significant role of GDH along with GS/GOGAT in production of nitrogen-rich amino acids for desiccation tolerance. Unlike higher plants S. bryopteris expressed GS only in cytosol. The enzyme had pH and temperature optima of 5.5 and 60°C, respectively, and it retained 96% activity on preincubation at 60°C for 30 min indicating thermostability. Hence, like higher plants the cytosolic GS from S. bryopteris has a conserved role in stress tolerance.
A history of human quarantine in Australia: settlement to 1980
Authors: Lightfoot Diane
Published: October 2020

Quarantine has been widely used for infection control in Australia since the time of settlement by Europeans. The history of human quarantine stations in Australia is discussed briefly here.
Neoliberalism’s “official crap art”?
Authors: Tsitsovits Ioannis
Published: October 2020

British writer Tom McCarthy has repeatedly taken aim at what he calls a “sentimental humanism” and the contemporary cult of the “authentic self”. This article investigates his work through the lens of that critique. Extrapolating from McCarthy’s public statements, I endeavour to delineate sentimental humanism as a mode of cultural production and flesh out his linking of it to a neoliberal political economy. I show how his antagonism manifests itself in his work, particularly his debut novel,Remainder. By contrast, his latest novel,Satin Island, marks a turning point in that trajectory. Although implicitly framed by its author as a way of thematising the challenges with which Big Data has confronted literature,Satin Islandmore specifically reveals that his anti-humanist agenda has also reached an impasse. Much of the logic behind the critique of sentimental humanism mounted byRemainder, I argue, is in a sense pre-empted or assimilated by the kinds of corporate digital environments described inSatin Island.
What dialog is absent from constructed dialog?
Authors: Rühlemann Christoph
Published: October 2020

This paper is concerned with constructed dialog in conversational storytelling. Based onClark & Gerrig’s (1990)demonstration theory, its focus is on what is absent from constructed dialog. To determine what is absent, a comparison is made between constructed dialog tokens and utterances in conversation. The inquiry uses both quantitative and qualitative methods. It is based on the Narrative Corpus (NC;Rühlemann & O’Donnell 2012), a corpus of conversational narratives extracted from the conversational component of the British National Corpus (BNC), and its systematic annotation of constructed dialog (that is, direct speech introduced by a quotative and free direct speech without any introducer). The quantitative comparison of verbalizations used in constructed dialog as opposed to verbalizations used in conversational utterances demonstrates that a particular utterance type is significantly missing from constructed dialog: the continuer utterance, whose basic function is to exhibit an understanding that a form of ‘telling’ by another speaker is going on. The qualitative analysis, based on a subset of storytellings from the NC that were re-analyzed acoustically and re-transcribed using Jeffersonian conventions based on the Audio BNC (Coleman et al. 2012), reveals a stark mismatch between the commonness of tellings in talk-in-interaction and their uncommonness in constructed dialog. The absence of continuers from constructed dialog is discussed against the backdrop of indexicality. I argue that continuers share the key properties of indexicals – semantic vacuity and an existential relationship with the ‘thing’ indicated – and can therefore be seen as indexicals themselves. As indexicals, intrinsically connected to the speech situation of their utterance, continuers cannot be included in constructed dialog, which typically occurs in a different speech situation with different interactional parameters. Finally, I offer initial thoughts on the underrepresentation of telling sequences in constructed dialog.
Early Universe in view of a modified theory of gravity
Authors: Mandal Ranajit , Saha Dalia , Alam Mohosin , Sanyal Abhik Kumar
Published: October 2020

We study the quantum evolution of the early Universe, its semi-classical analogue together with inflationary regime, in view of a generalized modified theory of gravity. The action is built by supplementing the non-minimally coupled scalar–tensor theory of gravity with scalar curvature squared term and a Gauss–Bonnet-dilatonic coupled term. It is generalized, since all the parameters are treated as arbitrary functions of the scalar field. It is interesting to explore the fact that instead of considering additional flow parameters, an effective potential serves the purpose of finding inflationary parameters. The dilaton stabilization issue appears here as a problem with reheating. Addition of a cosmological constant term alleviates the problem, and inflation is effectively driven by the vacuum energy density. Thus Gauss–Bonnet term might play a significant role in describing late-time cosmic evolution.
Shadows around the q-metric
Authors: Arrieta-Villamizar J A , Velásquez-Cadavid J M , Pimentel O M , Lora-Clavijo F D , Gutiérrez-Piñeres A C
Published: October 2020

One crucial problem in relativistic astrophysics is that of the nature of black hole candidates. It is usually assumed that astrophysical black holes are described by the Schwarzschild or Kerr space–times; however, there is no direct evidence to assert this. Moreover, there are various solutions in general relativity that can be alternatives to black holes, usually called black hole mimickers. In this work, we study the shadow produced by a compact object described by the q-metric, which is the simplest static and axially symmetric solution of Einstein equations with a non-vanishing quadrupole moment. This particular space–time has the property of containing an independent parameter q, which is related to the compact object deformation. The solution corresponds to naked singularities for some specific values of this parameter. Additionally, we analyze the eigenvalues of the Riemann tensor using the SO(3, C) representation, which allows us to find, in an invariant way, regions where there may be repulsive effects. Furthermore, we numerically solve the motion equations to show the shadow, the Einstein ring, and the gravitational lensing to establish a possible signature of such repulsive effects. We found that as q is smaller, the Einstein ring decreases, but the shape is the same as the Schwarzschild black hole case. However, for values of q lower or equal than −0.5, repulsive gravitational effects appear in the gravitational lensing close to the compact object, where a strong dependence of the system to the initial conditions seems to take place.
Electron–ion coincidence spectroscopy of a large organic molecule: photofragmentation of avobenzone after valence and core ionisation
Authors: Abid Abdul Rahman , Pelimanni Eetu , Reinhardt Maximilian , Boudjemia Nacer , Kivimäki Antti , Huttula Marko , Björneholm Olle , Patanen Minna
Published: October 2020

The Avobenzone (AVOB) molecule is very photoactive and undergoes irreversible degradation upon irradiation. We studied its valence and core-level (C1s and O1s) photoionisation and subsequent photofragmentation with photoelectron spectroscopy and photoelectron–photoion–photoion coincidence (PEPIPICO) spectroscopy. AVOB is one of the largest molecules studied with this technique. The results show that the AVOB molecule dissociates into an extensive range of fragments by different pathways with little element or site-selectivity. The coincident maps were used to determine selected fragment separation sequences by analysing the slopes of patterns from ion pairs after the core ionisation. Charge delocalisation over the benzene rings and their relative stability favor fragmentation by cleavage of the bridge between them.
X-ray scattering signatures of early-time accelerations in iodine dissociation
Authors: Gabalski Ian , Ware Matthew R , Bucksbaum Philip H
Published: October 2020

Ultrafast time-resolved x-ray scattering (TRXS) from a photoexcited molecular ensemble measures a distribution S(Q, τ) of the x-ray momentum transfer Q and pump-probe delay τ in which all modes of motion induced by the excitation overlap. Frequency-resolved x-ray scattering (FRXS) based on

S

̃

(

Q
,
ω

)

separates each oscillation and dissociation channel in the TRXS data, enabling measurements of vibrational frequencies and phases, and dissociation velocities and time shifts. Here we extend FRXS analysis to study early-time accelerations as well. We show how these appear as diffuse scattering patterns with characteristic phase evolution in FXRS and we develop a set of transformations that isolate individual channels to measure the early-time accelerated motion. This procedure is used to analyze diatomic iodine x-ray scattering data with multiple dissociations, and the ability of this technique to characterize early-time accelerations of one dissociation channel even in the presence of another dissociation is demonstrated.
Argon/dust and pure argon pulsed plasmas explored using a spatially-averaged model
Authors: Denysenko I B , Stefanović I , Mikikian M , Kovacevic E , Berndt J
Published: October 2020

The properties (densities of electrons and metastable argon atoms, effective electron temperature and dust charge) of argon/dust and pure argon pulsed plasmas are studied using a spatially-averaged model. The calculated time-dependencies for the densities of electrons and metastable atoms are compared with the experimental measurements and are found to be in a good qualitative agreement. It is analyzed how the plasma properties depend on the shape of the electron energy probability function (EEPF), the pulsing frequency and the duty cycle for both dust-free and dusty plasma. The analysis reveals that the agreement between theory and experiment is better with Druyvesteyn EEPF than the Maxwellian EEPF. Further, the variation in the pulsing frequency ν
p differently affects the metastable density n
m in a dust-free and in a dusty plasma. For large ν
p, the metastable density in the dust-free pulsed plasma is larger than in the continuous-wave (CW) discharge, while the opposite is obtained in the presence of dust particles. This difference probably arises because of faster variation in the effective electron temperature in the dusty plasma due to collection of electrons by dust particles. Our calculations also show that dust particles may affect the behavior of electron density in the beginning of the on-period due to an enhancement in electron collection by dust particles.
Long-lived species in plasma-activated water generated by an AC multi-needle-to-water discharge: effects of gas flow on chemical reactions
Authors: Liu Kun , Ren Wei , Ran Congfu , Zhou Rusen , Tang Weibin , Zhou Renwu , Yang Zhihao , Ostrikov Kostya (Ken)
Published: October 2020

Plasma-activated water (PAW) represents a promising green antibacterial agent for biomedical and agricultural applications. In this study, a novel AC multi-needle-to-water discharge device was developed to investigate the effects of gas flow on the generation and chemical composition of PAW. It is shown that the concentrations of

NO

3
−

and N(III) (

NO

2
−

and

HN

O

2

) in the PAW both increased with an extension of the plasma-processing time and a reduction of the gas-flow rate. The absorption of gas-phase products carried by the gas flow from the discharge chamber was found to be beneficial for the generation of both

NO

3
−

and N(III) in the PAW at a gas flow rate of 20–60 L h−1, yet their concentrations were still lower than those without any feeding gas. As opposed to

NO

3
−

or N(III), the

H

2

O

2

concentration in the plasma-activated phosphate buffer solution (PAPBS) increased under stronger gas flows and was almost unaffected by absorption in PAPBS. The pH value of PAW increased at higher gas flow rates. A comparison of the N(III) in PAW and PAPBS reflects the effects of the reactions of

NO

2
−

and

H

2

O

2

in the two different working liquids. To quantify the effects of gas flow on the discharge characteristics, gas temperatures were calculated from the optical emission spectra and were proven to be flow-independent near the discharge channel. Fourier transform infrared (FTIR) measurements of the gaseous products during the discharge, and further analysis of possible reaction pathways indicated that by controlling the gas flow in the multi-needle-to-water discharge system, the concentration of long-lived species in PAW could be tuned, which might favor the generation of

ONOOH

.

These findings contribute to a better understanding of effective electric discharge-related mechanisms for enhancing the biochemical and chemical activities of PAW.
Effect of electrode temperature on radiofrequency vacuum breakdown characteristics
Authors: Uimanov I V , Shmelev D L , Barengolts S A
Published: October 2020

The results of a numerical simulation of the heating of a microprotrusion on the surface of a copper electrode under the influence of radiofrequency electromagnetic fields, performed for different temperatures of the electrode, are presented. The calculation model describes self-consistently the thermal processes in the electron and phonon subsystems, the electron emission, and the effect of the space charge of emitted electrons. It has been shown that when the initial electrode temperature is increased to 1000 K, the time of heating of the surface microprotrusion to a critical temperature decreases by a factor of 1.5–1.9, namely, to values ranging from a few to tens of nanoseconds. This may significantly increase the probability of radiofrequency vacuum breakdown on the surface of the accelerating structure of an electron-positron collider.
Optically induced topological phase transition in two dimensional square lattice antiferromagnet
Authors: Luo Ma
Published: October 2020

The two dimensional square lattice antiferromagnet with spin–orbit coupling and nonsymmorphic symmetry is recently found to be topological insulator (TI). We theoretically studied the Floquet states of the antiferromagnetic crystal with optical irradiation, which could be applicable in opto-spintronic. An optical irradiation with circular polarization induces topological phase transition into quantum Anomalous Hall phase with varying Chern number. At the phase boundaries, the Floquet systems could be semimetal with one, two or three band valleys. A linear polarized optical field induces effective antiferromagnetic exchange field, which change the phase regime of the TI. At the intersection of two phase boundaries, the bulk band structure is nearly flat along one of the high symmetry line in the first Brillouin zone, which result in large density of states near to the Fermi energy in bulk and nanoribbons.
A motor-imagery channel-selection method based on SVM-CCA-CS
Authors: Wang Qisong , Cao Tianao , Liu Dan , Zhang Meiyan , Lu JingYang , Bai Ou , Sun Jinwei
Published: October 2020

In electroencephalography, multi-channel electroencephalogram (EEG) signals are usually utilized to improve classification accuracy. However, a large set of EEG channels increases the computational complexity, reduces the real-time performance and causes wearability difficulties. Channel selection methods have been widely investigated to reduce the number of channels with an acceptable loss of accuracy for EEG-based motor-imagery recognition. In this paper, we present a novel algorithm, called Support Vector Machine-Canonical Correlation Analysis-Channel Selection (SVM-CCA-CS). First, the energy features of the wavelet packet subnodes of the motor-imagery EEG signals are extracted. Then the weights of feature groups are calculated as initial channel weights, based on the CCA algorithm. The initial channel weights are further adjusted, according to the contribution of each channel to the classification accuracy via SVM, and the top channels with larger weights are eventually selected. The results show that the average accuracy of all subjects can reach 80.03% by using the first 30 channels with the largest weights from among the total of 118 channels. For the right hand and foot motor-imagery tasks, the generally applicable optimal channels are mostly located in the left hemisphere. Our generally applicable channel observation of the whole brain cortex suggests contralateral control correspondence: for unilateral motor imagery, the optimal channels are concentrated in the contralateral hemisphere. This is consistent with the contralateral control of the body by the human brain: the majority of the human motor and sensory fibers tend to control the contralateral limbs and pass through the midline of the body. Our proposed method provides optimal acquisition and analysis of the positions of EEG signals in specific motor-imagery tasks.
Optical and magnetic resonance imaging approaches for investigating the tumour microenvironment: state-of-the-art review and future trends
Authors: Prasad Saumya , Chandra Anil , Cavo Marta , Parasido Erika , Fricke Stanley , Lee Yichien , D’Amone Eliana , Gigli Giuseppe , Albanese Chris , Rodriguez Olga , del Mercato Loretta L
Published: October 2020

The tumour microenvironment (TME) strongly influences tumorigenesis and metastasis. Two of the most characterized properties of the TME are acidosis and hypoxia, both of which are considered hallmarks of tumours as well as critical factors in response to anticancer treatments. Currently, various imaging approaches exist to measure acidosis and hypoxia in the TME, including magnetic resonance imaging (MRI), positron emission tomography and optical imaging. In this review, we will focus on the latest fluorescent-based methods for optical sensing of cell metabolism and MRI as diagnostic imaging tools applied both in vitro and in vivo. The primary emphasis will be on describing the current and future uses of systems that can measure intra- and extra-cellular pH and oxygen changes at high spatial and temporal resolution. In addition, the suitability of these approaches for mapping tumour heterogeneity, and assessing response or failure to therapeutics will also be covered.
Solution processed nanostructured hybrid materials based on PbS quantum dots and reduced graphene oxide with tunable optoelectronic properties
Authors: Lara-Canche A R , Garcia-Gutierrez D F , Torres-Gomez N , Reyes-Gonzalez J E , Bahena-Uribe D , Sepulveda-Guzman S , Hernandez-Calderon I , García Gutierrez D I
Published: October 2020

Nanostructured hybrid materials (NHMs) are promising candidates to improve the performance of several materials in different applications. In the case of optoelectronic technologies, the ability to tune the optical absorption of such NHMs is an appealing feature. Along with the capacity to transform the absorbed light into charge carriers (CC), and their consequently efficient transport to the different electrodes. In this regard, NHM based on graphene-like structures and semiconductor QDs are appealing candidates, assuming the NHMs retain the light absorption and CC photogeneration properties of semiconductor QDs, and the excellent CC transport properties displayed by graphene-like materials. In the current work a solution-processed NHM using PbS quantum dots (QDs) and graphene oxide (GO) was fabricated in a layer-by-layer configuration by dip-coating. Afterwards, these NHMs were reduced by thermal or chemical methods. Reduction process had a direct impact on the final optoelectronic properties displayed by the NHMs. All reduced samples displayed a decrement in their resistivity, particularly the sample chemically reduced, displaying a 107 fold decrease; mainly attributed to N-doping in the reduced graphene oxide (rGO). The optical absorption coefficients also showed a dependence on the rGO’s reduction degree, with reduced samples displaying higher values, and sample thermally reduced at 300 °C showing the highest absorption coefficient, due to the combined absorption of unaltered PbS QDs and the appearance of sp2 regions within rGO. The photogenerated current increased in most reduced samples, displaying the highest photocurrent the sample reduced at 400 °C, presenting a 2500-fold increment compared to the NHM before reduction, attributed to an enhanced CC transfer from PbS QDs to rGO, as a consequence of an improved band alignment between them. These results show clear evidence on how the optoelectronic properties of NHMs based on semiconductor nanoparticles and rGO, can be tuned based on their configuration and the reduction process parameters.
Fabrication of black TiO2−x
/NiFe2O4 supported on diatomaceous earth with enhanced sonocatalytic activity for ibuprofen mitigation
Authors: Wu Qiong
Published: October 2020

This study reports a facile fabrication of black TiO2−x
/NiFe2O4 (Ti3+ self-doped titania coupled with nickel ferrite), an efficient sonocatalyst for ibuprofen (IBP) mitigation. Compared with TiO2−x
or NiFe2O4, TiO2−x
/NiFe2O4 heterojunction displayed higher sonocatalytic activity, and their immobilization onto diatomaceous earth further enhanced mitigation efficiency due to the synergy between adsorption and sonocatalysis. About 96.7% of 10 mg l−1 IBP was removed in 100 min using 0.7 g l−1 catalyst at pH = 6, with the ultrasonic power of 144 W and frequency of 60 KHz. Quenching experiment results demonstrated the roles of reactive species. The intermediates during IBP sono-oxidation were determined by HPLC-MS method, and the acute toxicity was evaluated. Furthermore, the reaction mechanism was proposed. The sonocatalyst revealed excellent reusability, suggesting itself promising for wastewater treatment.
Inclusion of quasi-vertex views in a brain-dedicated multi-pinhole SPECT system for improved imaging performance
Authors: Auer Benjamin , Zeraatkar Navid , Goding Justin C , Könik Arda , Fromme Timothy J , Kalluri Kesava S , Furenlid Lars R , Kuo Phillip H , King Michael A
Published: October 2020

With brain-dedicated multi-detector systems employing pinhole apertures the usage of detectors facing the top of the patient’s head (i.e. quasi-vertex (QV) views) can provide the advantage of additional viewing from close to the brain for improved detector coverage. In this paper, we report the results of simulation and reconstruction studies to investigate the impact of the QV views on the imaging performance of AdaptiSPECT-C, a brain-dedicated stationary SPECT system under development. In this design, both primary and scatter photons from regions located inferior to the brain can contribute to SPECT projections acquired by the QV views, and thus degrade AdaptiSPECT-C imaging performance. In this work, we determined the proportion, origin, and nature (i.e. primary, scatter, and multiple-scatter) of counts emitted from structures within the head and throughout the body contributing to projections from the different AdaptiSPECT-C detector rings, as well as from a true vertex view detector. We simulated phantoms used to assess different aspects of image quality (i.e. uniform activity concentration sphere, and Derenzo), as well as anthropomorphic phantoms with different count levels emulating clinical 123I activity distributions (i.e. DaTscan and perfusion). We determined that attenuation and scatter in the patient’s body greatly diminish the probability of the photons emitted outside the volume of interest reaching to detectors and being recorded within the 15% photopeak energy window. In addition, we demonstrated that the inclusion of the residual of such counts in the system acquisition does not degrade visual interpretation or quantitative analysis. The addition of the QV detectors improves volumetric sensitivity, angular sampling, and spatial resolution leading to significant enhancement in image quality, especially in the striato-thalamic and superior regions of the brain. Besides, the use of QV detectors improves the recovery of clinically relevant metrics such as the striatal binding ratio and mean activity in selected cerebral structures. Our findings proving the usefulness of the QV ring for brain imaging with 123I agents can be generalized to other commonly used SPECT imaging agents labelled with isotopes, such as 99mTc and likely 111In.
Detection of transient neurotransmitter response using personalized neural networks
Authors: Klyuzhin Ivan S , Bevington Connor W J , Cheng Ju-Chieh (Kevin) , Sossi Vesna
Published: October 2020

Measurement of stimulus-induced dopamine release and other types of transient neurotransmitter response (TNR) from dynamic positron emission tomography (PET) images typically suffers from limited detection sensitivity and high false positive (FP) rates. Measurement of TNR of a voxel-level can be particularly problematic due to high image noise. In this work, we perform voxel-level TNR detection using artificial neural networks (ANN) and compare their performance to previously used standard statistical tests. Different ANN architectures were trained and tested using simulated and real human PET imaging data, obtained with the tracer [11C]raclopride (a D2 receptor antagonist). A distinguishing feature of our approach is the use of ‘personalized’ ANNs that are designed to operate on the image from a specific subject and scan. Training of personalized ANNs was performed using simulated images that have been matched with the acquired image in terms of the signal, resolution, and noise.

In our tests of TNR detection performance, the F-test of the linear parametric neurotransmitter PET model fit residuals was used as the reference method. For a moderate TNR magnitude, the areas under the receiver operating characteristic curves in simulated tests were 0.64 for the F-test and 0.77–0.79 for the best ANNs. At a fixed FP rate of 0.01, the true positive rates were 0.6 for the F-test and 0.8–0.9 for the ANNs. The F-test detected on average 28% of a 8.4 mm cluster with a strong TNR, while the best ANN detected 47%. When applied to a real image, no significant abnormalities in the ANN outputs were observed. These results demonstrate that personalized ANNs may offer a greater detection sensitivity of dopamine release and other types of TNR compared to previously used method based on the F-test.
Hydrodynamic quantum analogs
Authors: Bush John W M , Oza Anand U
Published: October 2020

The walking droplet system discovered by Yves Couder and Emmanuel Fort presents an example of a vibrating particle self-propelling through a resonant interaction with its own wave field. It provides a means of visualizing a particle as an excitation of a field, a common notion in quantum field theory. Moreover, it represents the first macroscopic realization of a form of dynamics proposed for quantum particles by Louis de Broglie in the 1920s. The fact that this hydrodynamic pilot-wave system exhibits many features typically associated with the microscopic, quantum realm raises a number of intriguing questions. At a minimum, it extends the range of classical systems to include quantum-like statistics in a number of settings. A more optimistic stance is that it suggests the manner in which quantum mechanics might be completed through a theoretical description of particle trajectories. We here review the experimental studies of the walker system, and the hierarchy of theoretical models developed to rationalize its behavior. Particular attention is given to enumerating the dynamical mechanisms responsible for the emergence of robust, structured statistical behavior. Another focus is demonstrating how the temporal nonlocality of the droplet dynamics, as results from the persistence of its pilot wave field, may give rise to behavior that appears to be spatially nonlocal. Finally, we describe recent explorations of a generalized theoretical framework that provides a mathematical bridge between the hydrodynamic pilot-wave system and various realist models of quantum dynamics.
Hinge solitons in three-dimensional second-order topological insulators
Authors: Tao Yu-Liang , Dai Ning , Yang Yan-Bin , Zeng Qi-Bo , Xu Yong
Published: October 2020

Higher-order topological insulators have recently witnessed rapid progress in various fields ranging from condensed matter physics to electric circuits. A well-known higher-order state is the second-order topological insulator in three dimensions with gapless states localized on the hinges. A natural question in the context of nonlinearity is whether solitons can exist on the hinges in a second-order topological insulator. Here we theoretically demonstrate the existence of stable solitons localized on the hinges of a second-order topological insulator in three dimensions when nonlinearity is involved. By means of systematic numerical study, we find that the soliton has strong localization in real space and propagates along the hinge unidirectionally without changing its shape. We further construct an electric network to simulate the second-order topological insulator. When a nonlinear inductor is appropriately involved, we find that the system can support a bright soliton for the voltage distribution demonstrated by stable time evolution of a voltage pulse.
Fully self-consistent calculation of β-decay half-lives within Skyrme energy density functional *
Authors: Wen Pei-Wei , Zhang Shi-Sheng , Cao Li-Gang , Zhang Feng-Shou
Published: October 2020

-decay half-lives of some magic and semi-magic nuclei have been studied in a fully self-consistent Skyrme Hartree-Fock (HF) plus charge-exchange random phase approximation (RPA). The self-consistency is addressed, in that the same Skyrme energy density functional is adopted in the calculation of ground states and Gamow-Teller excited states. First, the impact of

terms on the

-decay half-lives is investigated by using the SGII interaction, revealing a large influence. Subsequently, numerical calculations are performed for the selected nuclei with Skyrme energy density functionals SGII, LNS, SKX, and SAMi. Finally, comparisons to available experimental data and predictions of different theoretical models are discussed.
Responsible or reckless? A critical review of the environmental and climate assessments of mineral supply chains
Authors: Calderon Jordan Lee , Bazilian Morgan , Sovacool B , Greene S
Published: October 2020

This paper critically reviews and identifies gaps in the methodologies used to analyze the environmental impacts of mineral and metal global supply chains. Of specific focus are assessments of the extraction and production of minerals and metals needed for a low-carbon energy future. Current trends and projections suggest that the future low-carbon energy system will have greater material needs than the current one. Thus, it is important to better understand the full impacts of increased resource extraction to help ensure a sustainable and just transition. This review reveals that existing methodologies are currently insufficient in capturing the full suite of environmental, social, and governance concerns. The copper supply chain is used as a case study to highlight areas that require refined or augmented methodologies, with an in-depth examination of the corporate practices of Freeport-McMoRan, Vale, and BHP. Together, this review of existing methodologies and examples from the copper supply chain highlight the incomplete and variable nature of environmental and climate reporting within the mining industry. Areas for future work are defined with the goal of advancing accounting frameworks for the mining industry and the associated supply chain.
Responsive high-resolution air quality index mapping using model, regulatory monitor, and sensor data in real-time
Authors: Schulte Nico , Li Xiang , Ghosh Jo Kay , Fine Philip M , Epstein Scott A
Published: October 2020

Interpolated regulatory monitor measurements that are used to calculate the Air Quality Index (AQI) have low spatial resolution and are less accurate where regulatory monitors are sparsely distributed, especially during episodic events such as wildfires and dust storms. In this paper, an AQI map that is more responsive and accurate than current formulations with 5 km spatial and hourly temporal resolution is constructed for Southern California using interpolated concentration fields. The fine particle mass (PM2.5) fields are calculated by combining regulatory-grade monitored concentrations, low-cost sensor measurements, and Community Multiscale Air Quality Model forecasts, using Residual Kriging (RK) interpolation to account for the uncertainty of each input component. The Ozone fields are calculated by combining regulatory monitor and model forecasted concentrations using RK. The interpolated concentration fields have root mean square interpolation errors (RMSE) of 5.59 µg m−3 (PM2.5) and 6.66 ppb (Ozone), smaller than corresponding RMSE of current inverse distance weighting methods used by the U.S. Environmental Protection Agency AirNOW system, and a previous interpolation method used by the South Coast Air Quality Management District. The inclusion of low-cost sensor measurements makes the AQI more responsive to wildfire events, with a PM2.5 RMSE of 7.73 µg m–3, a significant improvement from the other interpolation methods. The mass of particles with an aerodynamic diameter smaller than 10 micrometers (PM10) calculated using natural neighbor interpolation of the difference, PM10—PM2.5, and carbon monoxide and nitrogen dioxide fields calculated using natural neighbor interpolation, have small but usually not statistically significant reductions of RMSE relative to the other interpolation methods. Quality control and correction procedures applied to the low-cost sensor measurements are described. Display of the blended AQI data on an interactive map in real time provides an important tool for the public to minimize their exposure to poor air quality in one of the most polluted regions in the United States.
Exhaled breath condensate biomarkers in critically ill, mechanically ventilated patients
Authors: Davis Michael D , Winters Brett R , Madden Michael C , Pleil Joachim D , Sessler Curtis N , Wallace M Ariel Geer , Ward-Caviness Cavin K , Montpetit Alison J
Published: October 2020

Pneumonia is a significant risk for critically ill, mechanically ventilated (CIMV) patients. Diagnosis of pneumonia generally requires a combination of clinician-guided diagnoses and clinical scoring systems. Exhaled breath condensate (EBC) can be safely collected non-invasively from CIMV patients. Hundreds of biomarkers in EBC are associated with acute disease states, including pneumonia. We evaluated cytokines in EBC from CIMV patients and hypothesized that these biomarkers would correlate with disease severity in pneumonia, sepsis, and death. EBC IL-2 levels were associated with chest radiograph severity scores (odds ratio = 1.68; 95% confidence interval = 1.09–2.60; P = 0.02). EBC TNF-α levels were also associated with pneumonia (odds ratio = 3.20; 95% confidence interval = 1.19–8.65; P = 0.02). The techniques and results from this study may be useful for all mechanically ventilated patients.
Institutional restructuring of fisheries management system for humphead wrasse (Cheilinus undulatus RÜPPELL 1835) in Anambas and Natuna, Riau Archipelago Province, Indonesia
Authors: Mujiyanto  , Sugianti Y , Garcia M G , Edrus I N
Published: October 2020

This policy analysis paper revisits the existing traditional institutions concerned with Humphead wrasse management in Anambas and Natuna, Riau Archipelago Province. It provides an analysis and synthesis of policies that could give direction to the formation and/or strengthening of existing institutions for the benefit of this endangered fish species and all concerned parties. Local community’s active involvement and participation is key to the sustainable development of fisheries resources. However, the local community’s economic empowerment would be impossible to achieve without institutional strengthening. The paper recommends that community-based institutional empowerment or the “group approach” should be considered in Anambas and Natuna’s fisheries management system for Humphead wrasse. Organized fishing communities can be effective government partners in the management of open fishing areas in their jurisdictions. Fishing communities also have a vision, mission or resource management strategy specific to their own needs, values and aspirations. Defining and articulating the community’s vision, mission and values are therefore crucial to the success of any community initiatives concerning fisheries revitalization programs. The paper also proposes a logical plan for Community-Based Coastal Resource Management (CBCRM) system for consideration of the local government units in Anambas and Natuna.