bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the use of virtual reality in intervention and rescue activities
Authors: Irimia Alin , Ghicioi Emilian , Pupăzan Daniel , Nicolescu Cristian
Published: January 2022

In recent years in the virtual reality the developers succeeded in creating an artificial environment that simulates reality so that the user has the impression of an almost real physical presence in the virtual world. By overlapping and synchronizing the projected images with spatial sounds and even forces that interact with the user, there is a detachment of the user from the real environment and an all-encompassing involvement in the virtual world. The virtual reality is present in aviation, medicine, military training and other top fields. The advantages of using the virtual environment are obvious for areas where inexperience can cause very high loss of life and material loss. Although the participants are immersed in the scenario of the virtual environment, the errors produced allow an evaluation of the mistakes made and their correction, the experience gained being then used in professional activity in the real world. Through the experience of the virtual environment, the fear of various dangers can be overcome, so that the objectives of the exercise can be fulfilled. The aim of the paper is to offer to the rescuers opportunities to interact with the elements of the virtual space to fulfill the purpose of the exercise.
Preliminary results of investigations related to the ecology of Urdari open-pit lake
Authors: Faur Florin , Apostu Izabela-Maria , Lazăr Maria
Published: January 2022

Flooding the remaining gaps of lignite open-pits and the formation of so-called open-pit lakes tends to become an increasingly common practice in Romania (in the Oltenia Mining Basin, where the lignite deposit contained in Dacian and Romanian formations was and is extracted through open-pits). This type of ecological reconstruction of former exploitation areas has been applied worldwide for quite a time, and there are many references in this regard in the scientific literature. In this context, the present paper aims to present some preliminary results regarding the ecology of these lakes, being taken as case study the lake formed in the remaining gap of Urdari open-pit, within the Rovinari Mining Basin. However, given the multitude of similar conditions (bioclimate, geological framework, the formation of the remaining gaps, etc.) in which they form, we appreciate that the conclusions of this study can be extrapolated for other lakes in the area (eg. South Peșteana). We point out from the outset that this study presents data on the existing biotope and biocenoses (restricted to species identification), without going into details about populations, ecosystem production, energy and matter flows within it, these investigations being foreseen for a future development stage of the present study.
Investigating atmosphere’s environmental components and work environment of a household landfill’s platform
Authors: Găman Angelica-Nicoleta , Simion Alexandru , Kovacs Marius , Kovacs Izabella
Published: January 2022

Household landfills can be important sources of air quality contamination if they do not comply with technological sorting and storage procedures. Also, workers' exposure to environmental hazards endangers their health over time. A significant amount of household waste is stored in cells, monthly, after a sorting process that leaves a considerable ecological footprint. In this study we analysed air quality at the boundary of a compliant household landfill, as well as the quality of work environment of landfill’s workers. To do this, we performed measurements on two levels (air quality and work environment) over three months, following different phases of waste disposal and different activities involving workers serving the facilities. From an applied perspective, results obtained from research activities provide clear answers to questions related to ways in which environmental components are affected by waste storage activities, and workers are exposed to professional noxious. Results show that the landfill deteriorates environment quality, over time, as well as health of workers. Topic relevance is in connection with its potential future contribution to development of knowledge in the approached field, to be able to quantify progress, once integrated systems for modern ecological collection and storage have legislative regulations.
Determination of the radon concentration in homes depending on the insulation used for the floor
Authors: Tataru Andreea Cristina , Stanci Aurora , Tataru Dorin
Published: January 2022

A current environmental problem is the presence of radon inside the house. Radon (222Rn) is a noble, colourless and odourless gas that comes from radioactive elements naturally present in rocks and soil. Being gas, it is released from the ground with a tendency to concentrate in closed spaces such as caves, mines, cellars but also in any rooms in the basement, ground floor or with poor ventilation. Due to the differences between the temperature inside and the soil, the radon in the soil will move naturally to the interior of the houses, concentrating in closed rooms. The accumulation of radon inside buildings is a consequence of technological progress. Insulation work, tightly closed windows, poor ventilation of rooms lead to unobservable increase in radon concentration inside. In this paper we aim to present the values of the concentration of radon accumulated inside a house depending on the way of insulating the floor.
Endovascular Management of Internal Carotid Artery Pseudoaneurysm Secondary to Pediatric Deep Neck Space Infection: A Case Report and Review of Literature
Authors: Rajagopal Rengarajan , Sharma Smily , Bagarhatta Meenu , Tiwari Sarbesh , Bagarhatta Rajeev
Published: January 2022

Pseudoaneurysms of extracranial internal carotid artery (ICA) are rare in children. Main causes include trauma, iatrogenic causes, and neck space infection. Prompt diagnosis and management is vital, in view of life-threatening complications like fatal airway hemorrhage and stroke. Endovascular management has currently become the preferred treatment strategy due to its minimally invasive nature and lower complication rates. We report a rare case of mycotic pseudoaneurysm of extracranial ICA in a 4-year-old child as a complication of neck space infection, which was successfully managed with endovascular parent artery occlusion.
Risk and Management of Intracerebral Hemorrhage in Patients with Bleeding Disorders
Authors: Dorgalaleh Akbar , Farshi Yadolah , Haeri Kamand , Ghanbari Omid Baradarian , Ahmadi Abbas
Published: January 2022

Intracerebral hemorrhage (ICH) is the most dreaded complication, and the main cause of death, in patients with congenital bleeding disorders. ICH can occur in all congenital bleeding disorders, ranging from mild, like some platelet function disorders, to severe disorders such as hemophilia A, which can cause catastrophic hemorrhage. While extremely rare in mild bleeding disorders, ICH is common in severe coagulation factor (F) XIII deficiency. ICH can be spontaneous or trauma-related. Spontaneous ICH occurs more often in adults, while trauma-related ICH is more prevalent in children. Risk factors that can affect the occurrence of ICH include the type of bleeding disorder and its severity, genotype and genetic polymorphisms, type of delivery, and sports and other activities. Patients with hemophilia A; afibrinogenemia; FXIII, FX, and FVII deficiencies; and type 3 von Willebrand disease are more susceptible than those with mild platelet function disorders, FV, FXI, combined FV–FVIII deficiencies, and type 1 von Willebrand disease. Generally, the more severe the disorder, the more likely the occurrence of ICH. Contact sports and activities can provoke ICH, while safe and noncontact sports present more benefit than danger. An important risk factor is stressful delivery, whether it is prolonged or by vacuum extraction. These should be avoided in patients with congenital bleeding disorders. Familiarity with all risk factors of ICH can help prevent occurrence of this diathesis and reduce related morbidity and mortality.
An ACS-NSQIP Analysis of Unicompartmental Knee Arthroplasty Trends from 2013 to 2018
Authors: Cochrane Niall , Belay Elshaday , Wu Mark , O'Donnell Jeffrey , Kim Billy , Seyler Thorsten
Published: January 2022

Unicompartmental knee arthroplasty (UKA) volume has increased with advances in implant design, perioperative protocols, and patient selection. This study analyzed national trends of UKA from 2013 to 2018 and the relationship between patient demographics and postoperative outcomes. Data on UKA (CPT 27446) from 2013 to 2018 was collected from the National Surgical Quality Improvement Program (NSQIP). Variables collected included patient demographics, American Society of Anesthesiology classification, functional status, NSQIP morbidity probability, operative time, length of stay, 30-day reoperation, and readmission rates. There was an increase in outpatient UKAs performed (920 in 2013; 11,080 in 2018) (p < 0.0001). Analysis of variance from 2013 to 2018 revealed significant decrease in patient body mass index (BMI) (32.5 in 2013; 31.5 in 2018) (p < 0.01) and NSQIP morbidity probability (0.014 in 2013; 0.011 in 2018) (p < 0.0001). Operative time increased (79.1 minutes in 2013; 84.4 minutes in 2018) (p < 0.01), but length of stay decreased (0.9 days in 2013; 0.5 days in 2018) (p < 0.0001). The number of all-cause and related readmissions decreased significantly (p < 0.045; p < 0.01). Age, male gender, BMI >40 and chronic obstructive pulmonary disease (COPD) were significant predictors for 30-day readmission. BMI >40 was a significant predictor for discharge destination. UKA has seen a rise in incidence from 2013 to 2018 with an increasing number of outpatient UKAs. Operative times and 30-day readmissions have both decreased in this time. BMI > 40 is predictive for discharge destination after UKA, while age, male gender, BMI >40, and COPD are independent risk factors for 30-day readmission.
Anteromedial Tibial Attachment in Single-Bundle Anterior Cruciate Ligament Reconstruction Can Represent Normal Kinematics in Computer Simulation
Authors: Nakamura Shinichiro , Tanaka Yoshihisa , Kuriyama Shinichi , Nishitani Kohei , Watanabe Mutsumi , Yamauchi Kenshiro , Song Young D. , Matsuda Shuichi
Published: January 2022

Tunnel position during anterior cruciate ligament (ACL) reconstruction is considered as an important factor to restore normal knee kinematics and to gain better clinical outcomes. It is still unknown where the optimal femoral and tibial tunnel position is located in single-bundle (SB) ACL reconstruction. The purposes of this study were to analyze the knee kinematics with various graft positions and to propose the optimal graft position during SB ACL reconstruction. A musculoskeletal computer simulation was used to analyze knee kinematics. Four attachments on the femoral side (anteromedial [AM], mid, posterolateral [PL], and over-the-top positions) and three attachments on the tibial side (AM, middle, and PL positions) were determined. The middle-bundle attachment was placed at the midpoint of the AM and PL bundle attachments for the femoral and tibial attachments. SB ACL reconstruction models were constructed to combine each of the four femoral attachments with each of three tibial attachments. Kinematic comparison was made among a double-bundle (DB) model and 12 SB reconstruction models during deep knee bend and stair descent activity. The tunnel position of the tibia had greater effect of knee kinematics than that of the femur. AM tibial attachment models showed similar medial and lateral anteroposterior positions to the DB model for both activities. Axial rotation in the AM tibial attachment models was similar to the DB model regardless of the femoral attachment, whereas greater maximum axial rotation was exhibited in the PL tibial attachment models, especially during stair descent activity. AM tibial attachment can represent normal knee kinematics, whereas the PL tibial attachment can induce residual rotational instability during high-demand activities. The AM tibial tunnel is recommended for SB ACL reconstruction.
Theories explaining the relationship between neighbourhood stressors and depressive symptoms
Authors: Cho Seungjong
Published: January 2022

This study synthesizes the current theoretical knowledge to explain the relationship between neighbourhood stressors and depressive symptoms. The two most relevant sociological theories, social disorganization theory and stress process theory, are identified. The current study carefully reviewed the two theories regarding their historical development and key conceptual aspects, beginning with the theoretical evolution of research on neighbourhood stressors and mental health. This study also provides detailed critiques on each theory and suggests how researchers can apply both theories to their empirical testing. For example, social disorganization theory points out the application of both objective and subjective aspects of neighbourhood stressors. Also, the stress process theory emphasizes the mediating or moderating role of psychosocial resources. In conclusion, this study suggests a conceptual model of neighbourhood stressors, psychosocial resources, and depressive symptoms.
Multi-scale observations of the magnetopause Kelvin–Helmholtz waves during southward IMF
Authors: Blasl K. A. , Nakamura T. K. M. , Plaschke F. , Nakamura R. , Hasegawa H. , Stawarz J. E. , Liu Yi-Hsin , Peery S. , Holmes J. C. , Hosner M. , Schmid D. , Roberts O. W. , Volwerk M.
Published: January 2022

In this study, we present the first observations from the Magnetospheric Multiscale (MMS) mission of the Kelvin–Helmholtz instability (KHI) at the dusk-flank magnetopause during southward interplanetary magnetic field conditions on September 23, 2017. The instability criterion for the KHI was fulfilled for the plasma parameters observed throughout the event. An analysis of the boundary normal vectors based on the application of the timing method onto the magnetic field and the electron density data and the minimum directional derivative method onto the magnetic field data shows signatures of surface waves in the plane parallel to the velocity shear. A comparison to 2D fully kinetic simulations demonstrates reasonable consistencies with the formation of surface waves generated by the KH instability, as well as the structures of rolled-up KH waves. The observations further indicated low density faster than sheath plasma as an indicator of rolled-up vortices, which is also consistent with the simulations. All of these results show that the observed waves and vortices are most likely generated by the KH instability. High-time resolution MMS measurements further demonstrate kinetic-scale electric field fluctuations on the low-density side of the edges of surface waves. Detailed comparisons with the simulations suggest that the observed fluctuations are generated by the lower-hybrid drift instability excited by the density gradient at the edges of these surface waves. These secondary effects can lead to a flattening of the edge layers, indicating the connection between kinetic and larger scales within the KH waves and vortices.
Annealing metallic glasses above Tg in order to accelerate the relaxation process in molecular dynamics simulations
Authors: Şopu D. , Yuan X. , Eckert J.
Published: January 2022

To bridge the gap between nano- and micro-seconds molecular dynamics simulations and milliseconds timescale phenomena in metallic glasses remains an area of active research. Through systematic control of the annealing parameters, we have been able to simulate metallic glasses resembling structures usually obtained by quenching at cooling rates used in the melt spinning process. Density, local order, and local entropy calculations predict metallic glasses with structures prepared at cooling rates orders of magnitude lower than those typically realized in atomistic modeling. Hence, annealing above Tg is an alternative to melt quenching simulations and offers the prospect of modeling well relaxed glassy structures that were not achievable before in molecular dynamics simulations.
Cs diffusion mechanisms in UO2 investigated by SIMS, TEM, and atomistic simulations
Authors: Panetier C. , Pipon Y. , Gaillard C. , Mangin D. , Amodeo J. , Morthomas J. , Wiss T. , Benedetti A. , Ducher R. , Dubourg R. , Moncoffre N.
Published: January 2022

Experimental investigations and atomistic simulations are combined to study the cesium diffusion processes at high temperature in UO2. After 133Cs implantation in UO2 samples, diffusion coefficients are determined using the depth profile evolution after annealing as measured by secondary ion mass spectrometry. An activation energy of 1.8 ± 0.2 eV is subsequently deduced in the 1300–1600 °C temperature range. Experimental results are compared to nudged elastic band simulations performed for different atomic paths including several types of uranium vacancy defects. Activation energies ranging from 0.49 up to 2.34 eV are derived, showing the influence of the defect (both in terms of type and concentration) on the Cs diffusion process. Finally, molecular dynamics simulations are performed, allowing the identification of preferential Cs trajectories that corroborate experimental observations.
Three-body potential energy surface for para-hydrogen
Authors: Ibrahim Alexander , Roy Pierre-Nicholas
Published: January 2022

We present a 3D isotropic ab initio three-body (para-H2)3 interaction potential energy surface (PES). The electronic structure calculations are carried out at the correlated coupled-cluster theory level, with single, double, and perturbative triple excitations. The calculations use an augmented correlation-consistent triple zeta basis set and a supplementary midbond function. We construct the PES using the reproducing-kernel Hilbert space toolkit [O. T. Unke and M. Meuwly, J. Chem. Inf. Model. 57, 1923 (2017)] with phenomenological and empirical adjustments to account for short-range and long-range behaviors. The (para-H2)3 interaction energies deviate drastically from the Axilrod–Teller–Muto (ATM) potential at short intermolecular separations. We find that the configuration of three para-H2 molecules at the corners of an equilateral triangle is responsible for the majority of the (para-H2)3 interaction energy contribution in a hexagonal-close-packed lattice. In cases where two para-H2 molecules are close to one another while the third is far away, the (para-H2)3 interaction PES takes the form of a modified version of the ATM potential. We expect the combination of this PES together with a first-principles para-H2–para-H2 adiabatic hindered rotor potential to outperform a widely used effective pair potential for condensed many-body systems of para-H2.
Difference-frequency chirped-pulse dual-comb generation in the THz region: Temporal magnification of the quantum dynamics of water vapor lines by >60 000
Authors: Stroud Jasper R. , Plusquellic David F.
Published: January 2022

A new difference-frequency method based on electro-optic phase modulators (EOMs) and two free-running lasers is reported to perform chirped-pulse dual-comb spectroscopy in the THz region. A variation of a near-IR interleaving scheme we recently reported has been developed to interleave the EOMs’ orders and sidebands and to map THz comb teeth into the radio-frequency region below 1 MHz. The down-converted comb teeth are shown to have transform limited widths of 1 Hz over a 1 s time scale. The dual chirp-pulsed scheme is used to measure the complex line shapes of two water vapor lines below 600 GHz and to temporally magnify the effects of rapid passage by more than 60 000. For the 11,0 ← 10,1 transition in H2O, a pressure dependent phase perturbation is observed in the rapid passage response over the magnified time scale in contrast to a uniform line shape transformation observed for the 21,1 ← 20,2 transition of D2O. The possible origins for this anomalous behavior are modeled and discussed. The method is applicable to any region where difference or sum frequency waves can be generated.
Effect of incoming boundary layer thickness on the flow dynamics of a square finite wall-mounted cylinder
Authors: Chen Guang , Li Xiao-Bai , Sun Bo , Liang Xi-Feng
Published: January 2022

This paper investigates the flow dynamics around a square finite wall-mounted square cylinder of two different aspect ratios (AR=H/D=6 and 10, H and D are the height and width, respectively) under six boundary layer thickness (δ/D=0.5–4.0, δ is the boundary layer thickness) using the improved delayed detached eddy simulation turbulence model. The Reynolds number based on the square cylinder width and incoming velocity is Re=1.4×104. The aerodynamic force, surface mean and fluctuating pressure, wake closure length, Reynolds stresses, turbulence production, and the anisotropy of turbulence are analyzed in detail to investigate the effect of AR and δ/D combinations. The Q-criterion vortex identification method is adopted to identify and classify the vortex structures of different AR and δ/D combinations. The parametric diagram based on AR and δ/D to predict the dipole/quadrupole wake structure proposed in Yauwenas et al. [“The effect of aspect ratio on the wake structure of finite wall-mounted square cylinders,” J. Fluid Mech. 875, 929–960 (2019)] is refined based on results of the present study (quadrupole wake for AR=6 with δ/D≥1.5 and AR=10 with δ/D≥1.0). The instantaneous space–time pressure distribution along the whole span proves the existence of cellular shedding (AR=10 for δ/D=0.5–2.0), and the spectral proper orthogonal decomposition technique is adopted to investigate the cellular shedding phenomenon and its distribution. With the increase in δ/D from 2.0 to 4.0, the cellular shedding process is absent, implying the inhibitory effect of increasing boundary layer thickness on the cellular shedding.
Gas of sub-recoiled laser cooled atoms described by infinite ergodic theory
Authors: Barkai Eli , Radons Günter , Akimoto Takuma
Published: January 2022

The velocity distribution of a classical gas of atoms in thermal equilibrium is the normal Maxwell distribution. It is well known that for sub-recoiled laser cooled atoms, Lévy statistics and deviations from usual ergodic behavior come into play. In a recent letter, we showed how tools from infinite ergodic theory describe the cool gas. Here, using the master equation, we derive the scaling function and the infinite invariant density of a stochastic model for the momentum of laser cooled atoms, recapitulating results obtained by Bertin and Bardou [Am. J. Phys. 76, 630 (2008)] using life-time statistics. We focus on the case where the laser trapping is strong, namely, the rate of escape from the velocity trap is R(v) ∝ |v|α for v → 0 and α > 1. We construct a machinery to investigate time averages of physical observables and their relation to ensemble averages. The time averages are given in terms of functionals of the individual stochastic paths, and here we use a generalization of Lévy walks to investigate the ergodic properties of the system. Exploring the energy of the system, we show that when α = 3, it exhibits a transition between phases where it is either an integrable or a non-integrable observable with respect to the infinite invariant measure. This transition corresponds to very different properties of the mean energy and to a discontinuous behavior of fluctuations. While the integrable phase is described by universal statistics and the Darling–Kac law, the more challenging case is the exploration of statistical properties of non-integrable observables. Since previous experimental work showed that both α = 2 and α = 4 are attainable, we believe that both phases could also be explored experimentally.
Fluid dynamics of dredging
Authors: Randall Robert E.
Published: January 2022

Centrifugal pumps are used for pumping slurry from the dredge cutter head or drag head located in front of the suction pipe inlet to the final placement site or dredge hopper. Cavitation is an important phenomenon that must be avoided on the suction side of the pump that is quantified by the net positive suction head. The settling velocity is important for determining whether the sediment settles to the bottom of the pipeline. There is a critical velocity for the slurry in the pipeline that must be maintained such that the dredged sediment remains in suspension and minimizes contact with the pipe wall to keep friction losses at a minimum. Friction losses and minor losses are calculated and input to the energy equation to determine the system head curve over a range of flow rates. The system head curve and pump head characteristic curve are used to evaluate the dredge pump head and flow requirements needed to satisfactorily transport the dredged sediment to the placement location. A submerged ladder pump is installed on the ladder or drag arm to avoid cavitation, and booster pumps are added along the discharge pipe to ensure the transport of slurry over long distances greater than a mile or 1.6 kilometers.
Effective mass of cavity-vibration polaritons formed in etalons with liquid carbon tetrachloride
Authors: Coe James V. , Erwin Justin D.
Published: January 2022

Etalons are pairs of parallel plate mirrors with wavelength-scale spacing that exhibit cavity modes, giving transmission maxima (fringes) due to constructive interference. Infrared transmission measurements as a function of angle were used to determine the effective mass of etalon cavity modes using a gap filled with air and then liquid carbon tetrachloride. The air-filled etalon gives results in agreement with pure photon expectations established herein. Liquids with vibrations having strong infrared transition intensity (vibrational strong coupling mode) can strongly perturb the pattern of transmission resonances, creating mixed states of infrared cavity modes and molecular vibrations, i.e., cavity-vibration polaritons. The effective mass of one cavity-vibration polariton close to the strong vibration of carbon tetrachloride is 4.36 times heavier than the pure photon cavity mode expectation, i.e., the mass factor vs pure light. The mass factors are largest when closest to the strong vibrational frequency, and they converge to the one far away from the strong vibration. This work gives quantitative values of the effective mass of cavity-vibration polariton states and is a diagnostic for the mixing of vibrations with etalon transmission.
Ground state of asymmetric tops with DMRG: Water in one dimension
Authors: Serwatka Tobias , Roy Pierre-Nicholas
Published: January 2022

We propose an approach to compute the ground state properties of collections of interacting asymmetric top molecules based on the density matrix renormalization group method. Linear chains of rigid water molecules of varying sizes and density are used to illustrate the method. A primitive computational basis of asymmetric top eigenstates with nuclear spin symmetry is used, and the many-body wave function is represented as a matrix product state. We introduce a singular value decomposition approach in order to represent general interaction potentials as matrix product operators. The method can be used to describe linear chains containing up to 50 water molecules. Properties such as the ground state energy, the von-Neumann entanglement entropy, and orientational correlation functions are computed. The effect of basis set truncation on the convergence of ground state properties is assessed. It is shown that specific intermolecular distance regions can be grouped by their von-Neumann entanglement entropy, which in turn can be associated with electric dipole–dipole alignment and hydrogen bond formation. Additionally, by assuming conservation of local spin states, we present our approach to be capable of calculating chains with different arrangements of the para and ortho spin isomers of water and demonstrate that for the water dimer.
X-ray absorption spectra of aqueous cellobiose: Experiment and theory
Authors: Akazawa Daisuke , Sasaki Takehiko , Nagasaka Masanari , Shiga Motoyuki
Published: January 2022

The hydration structure of cellulose is very important for understanding the hydrolysis of cellulose at the molecular level. In this paper, we report a joint experimental and theoretical study on x-ray absorption spectroscopy (XAS) of aqueous cellobiose, a disaccharide unit of cellulose. In the experimental part, high resolution measurements of the carbon K-edge XAS spectra were taken. In the theoretical part, ab initio molecular dynamics simulations and ensemble calculations of electronic excited states were performed to obtain the continuous XAS spectra. The XAS spectra were found to have three characteristic peaks at 289.3, 290.7, and 293.6 eV, each representing the absorption by carbon atoms of the alcohol group, the hemiacetal group, and both of these functional groups. It was found that the peak heights in the spectrum change considerably over the temperature range of 25–60 °C, which is a reflection of the number of hydrogen bonds between cellobiose and water. We suggest that this spectral change could be useful information for identifying the hydration of cellulose in various environments.
Revisiting the link between magnetic properties and chemisorption at graphene nanoribbon zigzag edge
Authors: Wei Ziyang , Sautet Philippe
Published: January 2022

Graphene has received tremendous interest in both chemical and physical fields. Among different edges of the graphene system, the zigzag edge terminated graphene nanoribbons (ZGNRs) show unique magnetic properties in the antiferromagnetic (AFM) state. However, to date, the understanding of ZGNR chemical properties is mainly based on the partial radical concept, and in previous studies, the energy differences between the ferromagnetic (FM) and AFM states are smaller than experimental evidence. Here, we report that the strongly constrained and appropriately normed functional gives a significantly larger energy difference, which matches the experimental observation. Furthermore, utilizing the energetics in the large difference case, we propose a conceptual supplement to the previous partial radical concept: the overall stabilization of the AFM state compared to the nonmagnetic (NM) state consists of two parts that affect the adsorption energy conversely. The NM-FM energy differences will strengthen the adsorption, being in line with the previous partial radical concept. The FM-AFM energy differences will instead weaken the adsorption. We perform calculations of H, OH, and LiS radical adsorption energies on ZGNRs to show that this weakening effect is numerically non-negligible: at least a ∼0.2 eV difference in the adsorption energies is found. We expect that this refinement of the partial radical concept can provide a more comprehensive understanding of the chemical properties of ZGNRs. The differences in adsorption energies for the H, OH, and LiS radicals found here lead to significant changes in the predicted reactivity of the ZGNR models.
Dopamine firing plays a dual role in coding reward prediction errors and signaling motivation in a working memory task
Authors: Sarno Stefania , Beirán Manuel , Falcó-Roget Joan , Diaz-deLeon Gabriel , Rossi-Pool Román , Romo Ranulfo , Parga Néstor
Published: January 2022

Little is known about how dopamine (DA) neuron firing rates behave in cognitively demanding decision-making tasks. Here, we investigated midbrain DA activity in monkeys performing a discrimination task in which the animal had to use working memory (WM) to report which of two sequentially applied vibrotactile stimuli had the higher frequency. We found that perception was altered by an internal bias, likely generated by deterioration of the representation of the first frequency during the WM period. This bias greatly controlled the DA phasic response during the two stimulation periods, confirming that DA reward prediction errors reflected stimulus perception. In contrast, tonic dopamine activity during WM was not affected by the bias and did not encode the stored frequency. More interestingly, both delay-period activity and phasic responses before the second stimulus negatively correlated with reaction times of the animals after the trial start cue and thus represented motivated behavior on a trial-by-trial basis. During WM, this motivation signal underwent a ramp-like increase. At the same time, motivation positively correlated with accuracy, especially in difficult trials, probably by decreasing the effect of the bias. Overall, our results indicate that DA activity, in addition to encoding reward prediction errors, could at the same time be involved in motivation and WM. In particular, the ramping activity during the delay period suggests a possible DA role in stabilizing sustained cortical activity, hypothetically by increasing the gain communicated to prefrontal neurons in a motivation-dependent way.
A quantitative framework reveals traditional laboratory growth is a highly accurate model of human oral infection
Authors: Lewin Gina R. , Stocke Kendall S. , Lamont Richard J. , Whiteley Marvin
Published: January 2022

Significance

Most microbial knowledge comes from experiments in laboratory models, despite the assumption that these artificial systems alter microbial physiology relative the native environment. We tested this assumption for an oral pathogen,Porphyromonas gingivalis, using 93 metatranscriptomes from periodontally healthy and diseased patients and 122 transcriptomes from experimental models. We discovered that a simple in vitro model, midlogarithmic growth in rich media, highly recapitulatesP. gingivalisgene expression in the human oral cavity, outperforming other models, including a murine infection model. These results support the biological relevance of decades of laboratory experiments with this pathogen and validate an accessible experimental model for studyingP. gingivalisbiology. Furthermore, these data provide a conceptual framework for understanding in situ gene expression across microbes.
Facile fabrication of TiO2/Bi5O7Br photocatalysts for visible-light-assisted removal of tetracycline and dye wastewaters
Authors: Salmanzadeh-Jamadi Zahra , Habibi-Yangjeh Aziz , Pouran Shima Rahim , Xu Xuefei , Wang Chundong
Published: January 2022

The emergence of persistent organic pollutants such as dyes and pharmaceuticals in the aquatic environment has created drastic concerns worldwide due to their toxicity and potential hazards to the environment. Accordingly, non-stoichiometric TiO2/Bi5O7Br nanocomposites were prepared by stirring method as a visible-light-effective photocatalyst for degradation of amoxicillin (AMX) and tetracycline (TC), as antibiotic pollutants, and rhodamine B (RhB), methylene blue (MB), and malachite green (MG), as dye pollutants. The physiochemical properties of the samples were studied using FESEM, TEM/HRTEM, XRD, EDX, UV–vis DRS, FT-IR, XPS, BET, PL, photocurrent, and EIS analyses. The TiO2/Bi5O7Br (40%) photocatalyst performed superior to TiO2, Bi5O7Br, and TiO2/BiOBr (40%) in photodegradation of the studied contaminants. The degradation rate constants of AMX, TC, MG, RhB, and MB over the TiO2/Bi5O7Br (40%) photocatalyst were 18.2‒32.5 folds greater than pure TiO2, 1.6‒17.3 times higher than pure Bi5O7Br, and 1.4‒13 times larger than TiO2/BiOBr (40%), respectively. Quenching studies showed that superoxide anion radicals and holes had major roles in photocatalytic elimination of TC. Importantly, TiO2/Bi5O7Br (40%) nanocomposite showed robust reusability with high degree of TC removal after four successive photocatalytic recycles. This research introduces a cost-effective, efficient, and reusable visible-light-triggered binary system based on TiO2 for decontamination of medicinal and dye polluted wastewaters.
Superconductor–insulator transitions in three-dimensional indium-oxide at high pressures
Authors: Hen Bar , Shelukhin Victor , Greenberg Eran , Rozenberg Gregory Kh , Kapitulnik Aharon , Palevski Alexander
Published: January 2022

Experiments investigating magnetic-field-tuned superconductor–insulator transition (HSIT) mostly focus on two-dimensional material systems where the transition and its proximate ground-state phases, often exhibit features that are seemingly at odds with the expected behavior. Here we present a complementary study of a three-dimensional pressure-packed amorphous indium-oxide (InOx) powder where granularity controls the HSIT. Above a low threshold pressure of ∼0.2 GPa, vestiges of superconductivity are detected, although neither a true superconducting transition nor insulating behavior are observed. Instead, a saturation at very high resistivity at low pressure is followed by saturation at very low resistivity at higher pressure. We identify both as different manifestations of anomalous metallic phases dominated by superconducting fluctuations. By analogy with previous identification of the low resistance saturation as a ‘failed superconductor’, our data suggests that the very high resistance saturation is a manifestation of a ‘failed insulator’. Above a threshold pressure of ∼6 GPa, the sample becomes fully packed, and superconductivity is robust, with T
C tunable with pressure. A quantum critical point at P
C ∼ 25 GPa marks the complete suppression of superconductivity. For a finite pressure below P
C, a magnetic field is shown to induce a HSIT from a true zero-resistance superconducting state to a weakly insulating behavior. Determining the critical field, H
C, we show that similar to the 2D behavior, the insulating-like state maintains a superconducting character, which is quenched at higher field, above which the magnetoresistance decreases to its fermionic normal state value.
Radiation modulated spin coupling in a double-stranded DNA model
Authors: López Alexander , Varela Solmar , Medina Ernesto
Published: January 2022

The spin activity in macromolecules such as DNA and oligopeptides, in the context of the chiral induced spin selectivity has been proposed to be due to the atomic spin–orbit coupling (SOC) and the associated chiral symmetry of the structures. This coupling, associated with carbon, nitrogen and oxygen atoms in biological molecules, albeit small (meV), can be enhanced by the geometry, and strong local polarization effects such as hydrogen bonding. A novel way to manipulate the spin degree of freedom is by modifying the spectrum using a coupling to the appropriate electromagnetic radiation field. Here we use the Floquet formalism in order to show how the half filled band Hamiltonian for DNA, can be modulated by the radiation to produce up to a tenfold increase of the effective SOC once the intrinsic coupling is present. On the other hand, the chiral model, once incorporating the orbital angular momentum of electron motion on the helix, opens a gap for different helicity states (helicity splitting) that chooses spin polarization according to transport direction and chirality, without breaking time reversal symmetry. The observed effects are feasible in physically reasonable parameter ranges for the radiation field amplitude and frequency.
Basis for the ICRP’s updated biokinetic model for systemic astatine
Authors: Leggett Rich , Samuels Caleigh
Published: January 2022

The International Commission on Radiological Protection (ICRP) recently updated its biokinetic models for workers in a series of reports called the OIR (occupational intakes of radionuclides) series. A new biokinetic model for astatine (At), the heaviest member of the halogen family, was adopted in OIR Part 5 (ICRP in press). Occupational intakes of radionuclides: Part 5). This paper provides an overview of available biokinetic data for At; describes the basis for the ICRP’s updated model for At; and tabulates dose coefficients for intravenous injection of each of the two longest lived and most important At isotopes, 211At and 210At. At-211 (T
1/2 = 7.214 h) is a promising radionuclide for use in targeted α-particle therapy due to several favourable properties including its half-life and the absence of progeny that could deliver significant radiation doses outside the region of α-particle therapy. At-210 (T
1/2 = 8.1 h) is an impurity generated in the production of 211At in a cyclotron and represents a potential radiation hazard via its long-lived progeny 210Po (T
1/2 = 138 days). Tissue dose coefficients for injected 210At and 211At based on the updated model are shown to differ considerably from values based on the ICRP’s previous model for At, particularly for the thyroid, stomach wall, salivary glands, lungs, spleen, and kidneys.
An integrated XFEM modeling with experimental measurements for optimizing thermal conductivity in carbon nanotube reinforced polyethylene
Authors: Bakalakos Serafeim , Kalogeris Ioannis , Papadopoulos Vissarion , Papadrakakis Manolis , Maroulas Panagiotis , Dragatogiannis Dimitrios A , Charitidis Costas A
Published: January 2022

The present paper investigates the thermal properties of carbon nanotube reinforced polyethylene and specifically its potential as highly conductive material. To this end, an integrated approach is proposed combining both numerical and experimental procedures. First, in order to study conductive heat transfer in two-phase materials with imperfect interfaces, a detailed numerical model is developed based on the extended finite element method, where material interfaces are modeled using the level set method. The thermal conductance at the interface of the carbon nanotubes and the polymer matrix is considered to be an unknown model parameter, the value of which is obtained by utilizing a series of experimental measurements of the composite material’s effective conductivity. The interfacial thermal conductance parameter value is inferred by calibrating the numerically predicted effective conductivity to the series of the corresponding experimental measurements. Once this parameter is estimated, the data-informed model is subsequently employed to provide reliable predictions of the effective conductivity of the composite for various weight fractions and configurations of carbon nanotubes in the parent material. Furthermore, microstructural morphologies that provide upper limits on the effective conductivity of the composite are identified via sensitivity analysis, demonstrating its potential as a highly conductive material.
Construction of a photo-controlled fluorescent switching with diarylethene modified carbon dots
Authors: Liuye Shiqi , Cui Shiqiang , Lu Mengmeng , Pu Shouzhi
Published: January 2022

Photo-controlled fluorescent switching is of great utility in fluorescence sensors, reversible data storage, and logic circuit, based on their modifiable emission intensity and spectra. In this work, a novel photo-controlled reversible fluorescent switching system was constructed based on photochromic diarylethene (DT) molecular modified fluorescent carbon dots (CDs). The fluorescent CDs acted as fluorescent donors and the photochromic diarylethene molecular functioned as acceptors in this fluorescent switching system. The fluorescence modulation efficiency of the fluorescent switching was determined to be 97.1%. The result was attributable to Förster resonance energy transfer between the CDs and the diarylethene molecular. The fluorescent switching could undergo 20 cycles without significant decay.
Global dynamics of a Lotka–Volterra competition patch model*
Authors: Chen Shanshan , Shi Junping , Shuai Zhisheng , Wu Yixiang
Published: January 2022

The global dynamics of the two-species Lotka–Volterra competition patch model with asymmetric dispersal is classified under the assumptions that the competition is weak and the weighted digraph of the connection matrix is strongly connected and cycle-balanced. We show that in the long time, either the competition exclusion holds that one species becomes extinct, or the two species reach a coexistence equilibrium, and the outcome of the competition is determined by the strength of the inter-specific competition and the dispersal rates. Our main techniques in the proofs follow the theory of monotone dynamical systems and a graph-theoretic approach based on the tree-cycle identity.
Asymptotic limits for a nonlinear integro-differential equation modelling leukocytes’ rolling on arterial walls
Authors: Milišić Vuk , Schmeiser Christian
Published: January 2022

We consider a nonlinear integro-differential model describing z, the position of the cell center on the real line presented in Grec et al (2018 J. Theor. Biol.
452 35–46). We introduce a new ɛ-scaling and we prove rigorously the asymptotics when ɛ goes to zero. We show that this scaling characterizes the long-time behavior of the solutions of our problem in the cinematic regime (i.e. the velocity

z

˙

tends to a limit). The convergence results are first given when ψ, the elastic energy associated to linkages, is convex and regular (the second order derivative of ψ is bounded). In the absence of blood flow, when ψ, is quadratic, we compute the final position z
∞ to which we prove that z tends. We then build a rigorous mathematical framework for ψ being convex but only Lipschitz. We extend convergence results with respect to ɛ to the case when ψ′ admits a finite number of jumps. In the last part, we show that in the constant force case [see model 3 in Grec et al (2018 J. Theor. Biol.
452 35–46), i.e. ψ is the absolute value)] we solve explicitly the problem and recover the above asymptotic results.
Existence of physical measures in some excitation–inhibition networks*
Authors: Tanzi Matteo , Young Lai-Sang
Published: January 2022

In this paper we present a rigorous analysis of a class of coupled dynamical systems in which two distinct types of components, one excitatory and the other inhibitory, interact with one another. These network models are finite in size but can be arbitrarily large. They are inspired by real biological networks, and possess features that are idealizations of those in biological systems. Individual components of the network are represented by simple, much studied dynamical systems. Complex dynamical patterns on the network level emerge as a result of the coupling among its constituent subsystems. Appealing to existing techniques in (nonuniform) hyperbolic theory, we study their Lyapunov exponents and entropy, and prove that large time network dynamics are governed by physical measures with the SRB property.
On Liouville-type theorems for the 2D stationary MHD equations
Authors: De Nitti Nicola , Hounkpe Francis , Schulz Simon
Published: January 2022

We establish new Liouville-type theorems for the two-dimensional stationary magneto-hydrodynamic incompressible system assuming that the velocity and magnetic field have bounded Dirichlet integral. The key tool in our proof is observing that the stream function associated to the magnetic field satisfies a simple drift–diffusion equation for which a maximum principle is available.
Stationary multi-kinks in the discrete sine-Gordon equation
Authors: Parker Ross , Kevrekidis P G , Aceves Alejandro
Published: January 2022

We consider the existence and spectral stability of static multi-kink structures in the discrete sine-Gordon equation, as a representative example of the family of discrete Klein–Gordon models. The multi-kinks are constructed using Lin’s method from an alternating sequence of well-separated kink and antikink solutions. We then locate the point spectrum associated with these multi-kink solutions by reducing the spectral problem to a matrix equation. For an m-structure multi-kink, there will be m eigenvalues in the point spectrum near each eigenvalue of the primary kink, and, as long as the spectrum of the primary kink is imaginary, the spectrum of the multi-kink will be as well. We obtain analytic expressions for the eigenvalues of a multi-kink in terms of the eigenvalues and corresponding eigenfunctions of the primary kink, and these are in very good agreement with numerical results. We also perform numerical time-stepping experiments on perturbations of multi-kinks, and the outcomes of these simulations are interpreted using the spectral results.