bluuebunny/crossref_metadata_2025 huggingface dataset:
The FOOT experiment: current status and future perspective for nuclear fragmentation studies in particle therapy and space radiation protection
Authors: Colombi Sofia
Published: April 2022

Nuclear fragmentation processes occurring in the beam-target interaction represent a potential source of hazard for humans’ health both in particle therapy and space exploration. The FragmentatiOn Of Target (FOOT) experiment aims to characterize both beam and target fragments, and to measure with great accuracy nuclear fragmentation cross sections interesting in cancer therapy and in long-lasting interplanetary missions. In this paper, the fragments reconstruction capabilities of the FOOT experimental setup is reported. FOOT future perspective of providing useful data to improve the modelling of neutron interactions is also discussed.
Doppler Ultrasound of the Umbilical Artery: Clinical Application
Authors: Rocha Ana Sá , Andrade Ana Rosa Araújo , Moleiro Maria Lúcia , Guedes-Martins Luís
Published: April 2022

Objective To provide a survey of relevant literature on umbilical artery Doppler ultrasound use in clinical practice, technical considerations and limitations, and future perspectives.

Methods Literature searches were conducted in PubMed and Medline, restricted to articles written in English. Additionally, the references of all analyzed studies were searched to obtain necessary information.

Results The use of this technique as a routine surveillance method is only recommended for high-risk pregnancies with impaired placentation. Meta-analyses of randomized trials have established that obstetric management guided by umbilical artery Doppler findings can improve perinatal mortality and morbidity. The values of the indices of Umbilical artery Doppler decrease with advancing gestational age; however, a lack of consensus on reference ranges prevails.

Conclusion Important clinical decisions are based on the information obtained with umbilical artery Doppler ultrasound. Future efforts in research are imperative to overcome the current limitations of the technique.
Analysis of ground distance effect on hypervelocity jet flow and stability of projectile in half-space
Authors: Li Zijie , Wang Hao
Published: April 2022

Many complex physical phenomena are involved in the firing of hypervelocity projectiles, especially near the ground. In fact, the range of influence is so wide that it is impossible to ignore the significant influence of the ground on the stability of the hypervelocity jet and the motion of the projectile. In this study, we established four three-dimensional numerical simulations under different launch conditions, including distances of 1.8, 1.5, 1.0, and 0.55 m above the ground. Taking a 300-mm-caliber counter-mass propelling gun as an example, which exhibits a characteristic flow field morphology under a velocity of 1730 m/s, we compared different flow phenomena at different heights from the ground. The results indicate that the hypervelocity muzzle shock wave is reflected by the ground and a new opposite-direction shock wave was created. The interaction between the muzzle shock wave and the new opposite-direction shock wave makes the pressure of the bottom half of the calculation domain much higher than that of the upper half. At the same time, along with the increase in pressure, which is generated on the ground, it even affects the shear layer around the projectile body. The projectile movement is disturbed by changes in lift and moment force, which alter several other parameters, such as the rotating angular velocity. Thus, the distance to the ground was found to be one of the significant influencing factors during the experiment.
Ultrafast infrared transient absorption spectroscopy of gas-phase Ni(CO)4 photodissociation at 261 nm
Authors: Cole-Filipiak Neil C. , Troß Jan , Schrader Paul , McCaslin Laura M. , Ramasesha Krupa
Published: April 2022

We employ ultrafast mid-infrared transient absorption spectroscopy to probe the rapid loss of carbonyl ligands from gas-phase nickel tetracarbonyl following ultraviolet photoexcitation at 261 nm. Here, nickel tetracarbonyl undergoes prompt dissociation to produce nickel tricarbonyl in a singlet excited state; this electronically excited tricarbonyl loses another CO group over tens of picoseconds. Our results also suggest the presence of a parallel, concerted dissociation mechanism to produce nickel dicarbonyl in a triplet excited state, which likely dissociates to nickel monocarbonyl. Mechanisms for the formation of these photoproducts in multiple electronic excited states are theoretically predicted with one-dimensional cuts through the potential energy surfaces and computation of spin–orbit coupling constants using equation of motion coupled cluster methods (EOM-CC) and coupled cluster theory with single and double excitations (CCSD). Bond dissociation energies are calculated with CCSD, and anharmonic frequencies of ground and excited state species are computed using density functional theory (DFT) and time-dependent density functional theory (TD-DFT).
Room temperature magnetic field modulation of diode-like behavior in Ca-doped BiFeO3 thin films
Authors: Wu Lei , Li Juanfei , Dong Chunhui , Wang Xiaoqiang , Li Jinsheng , Li Mingya
Published: April 2022

Bi1-xCaxFeO3 (x = 0, 0.1) thin films were synthesized by a sol-gel spin coating method. A diode-like current–voltage characteristic was investigated in a Bi0.9Ca0.1FeO3 (BCFO) thin film. By Ca element doping, the current–voltage characteristic was changed from a traditional symmetric variation to a diode-like behavior. Besides, the modulation effects of a magnetic field on Pt/BCFO/Pt/Ti/SiO2/Si devices have been investigated. Using some micro-analysis methods, such as x-ray photoelectron spectroscopy and transmission electron microscopy, possible mechanisms were discussed on the basis of an oxygen vacancy modulated Schottky-like barrier. The control of the resistance state with the magnetic field means larger degrees of freedom, and this is crucial for further application of BiFeO3-based materials in higher density memory devices.
Defectors in bad circumstances possessing higher reputation can promote cooperation
Authors: Zhang Lan , Zhang Liming , Huang Changwei
Published: April 2022

In nature and human society, social relationships and behavior patterns are usually unpredictable. In any interaction, individuals will constantly have to deal with prior uncertainty. The concept of “reputation” can provide some information to mitigate such uncertainty. In previous studies, researchers have considered that only cooperators are able to maintain a high reputation; no matter the circumstances of a defector, they are classified as a faithless individual. In reality, however, some individuals will be forced to defect to protect themselves against exploitation. Therefore, it makes sense that defectors in bad circumstances could also obtain higher reputations, and cooperators can maintain higher reputations in comfortable circumstances. In this work, the reputations of individuals are calculated using the fraction of their neighbors who have the same strategy. In this way, some defectors in a population may obtain higher reputations than some cooperators. We introduce this reputation rule using heterogeneous investments in public goods games. Our numerical simulation results indicate that this reputation rule and heterogeneous investments can better stimulate cooperation. Additionally, stronger investment heterogeneity can further increase the level of cooperation. To explain this phenomenon, dynamical evolution is observed in Monte Carlo simulations. We also investigated the effects of the noise intensity of the irrational population and the original proportion of cooperation in the population. The robustness of this cooperation model was also considered with respect to the network structure and total investment, and we found that the conclusions remained the same.
Ultra-broadband and high purity tapered mode converter for mode division multiplexing systems
Authors: Yu Xuelian , Zuo Shanshan , Wang Pengfei
Published: April 2022

This paper proposes a three-section tapered mode converter that can convert guided optical mode LP01 to LP02. The coupling section, the coupling enhancement section, and the undesired power reduction section are connected in sequence and shows operation with ultra-bandwidth of 178 nm with over 20 dB extinction ratio, the LP02 normalized power accounted for the high proportion. The proposed structure represents ultra-broadband and high purity component for use in mode division multiplexing systems.
Novel models for predicting the shape and motion of an ascending bubble in Newtonian liquids using machine learning
Authors: She Wen-Xuan , Zuo Zheng-Yu , Zhao Hang , Gao Qi , Zhang Ling-Xin , Shao Xue-Ming
Published: April 2022

As a conventional and persistent topic, a single bubble freely ascending in Newtonian liquids is investigated based on its shape and motion predictions using the strategy of machine learning. The dataset for training, validating, and testing neural networks is composed of the current experimental results and the extensively collected data from previous research works, which covers a broad range of dimensionless parameters that are 10−3≤Re≤105, 10−2≤Eo≤103, 10−5≤We≤102, and 10−14≤Mo≤107. The novel models of the aspect ratio E and drag coefficient CD are proposed based on a backpropagation neural network. The comparisons of the conventional correlations indicate that the new E model presents a significant superiority. This E model also has a good capability to predict the minimum E as about 0.26 that is consistent with the theoretical value EWe→∞≈0.25. Moreover, the CD models are divided into E-independent and E-dependent types. The performances of these two type models are quite similar and both agree well with the experimental results. The errors of the CD predictions for Re > 1 are mostly in the range of ±20%.
Wall-cooling effects on secondary instabilities of Mack mode disturbances at Mach 6
Authors: Xu Jiakuan , Liu Jianxin
Published: April 2022

In hypersonic boundary layers, Mack modes play a crucial role in flow instability, whose secondary instability is a hot research topic. Since hypersonic flight vehicles will probably work under high-stagnation temperature conditions, which significantly affect the aerodynamic heating calculation and aero-thermal protection design of hypersonic vehicles, it is necessary to compare the primary and secondary instabilities in high-stagnation temperature boundary layers and that in the Boeing/AFOSR Mach 6 quiet tunnel (BAM6QT). Herein, wall-cooling is adopted in order not to consider chemical reactions. With the same freestream temperature of 100 K, two Mach 6 boundary layers with the wall temperature of 20 and 600 K, corresponding to the cooled wall condition and the quiet wind tunnel condition, respectively, are chosen to conduct the linear/non-linear stability and the secondary instability analysis. Our results show that the most dangerous Mack mode originates from a fast discrete mode in the present cooled-wall flow and the most dangerous Mack mode is born from the slow discrete modes in BAM6QT boundary layers. Furthermore, when the primary amplitude of Mack mode disturbances is large, the fundamental resonance always dominates the secondary instability, resulting in steady streaky structures that have the largest amplitude in the spectrum. In addition, the present results point out that the distribution of the eigenfunctions of the fundamental modes and subharmonic modes are significantly different under various wall-temperatures. What is more, different ratios of wall temperature to incoming flow temperature have changed the spanwise wave-angle of the secondary disturbances.
Effects of alloying and deposition temperature on phase formation and superconducting properties of TiZrTaNb-based high entropy-alloy films
Authors: Shu Rui , Zhang Xiaofu , Rao Smita G. , le Febvrier Arnaud , Eklund Per
Published: April 2022

A variety of bulk high-entropy alloy superconductors have been recently discovered; however, for thin films, only the TaNbHfZrTi high-entropy alloy system has been investigated for its superconducting properties. Here, (TiZrNbTa)1−xWx and (TiZrNbTa)1−xVx superconducting films have been produced by DC magnetron sputtering at different growth temperatures. The phase formation and superconducting behavior of these films depend on the content of alloying x and deposition temperature. A single body-centered cubic (bcc) phase can be formed in the low x range with enough driving energy for crystallinity, but phase transition between amorphous or two bcc structures is observed when increasing x. The highest superconducting transition temperature Tc reaches 8.0 K for the TiZrNbTa film. The superconducting transition temperature Tc of these films deposited at the same temperature decreases monotonically as a function of x. Increasing deposition temperature to 400 °C can enhance Tc for these films while retaining nearly equivalent compositions. Our experimental observations suggest that Tc of superconducting high entropy alloys relate to the atomic radii difference and electronegativity difference of involved elements beyond the valence electron number.
Binary classification of welding defect based on deep learning
Authors: Wang Xiaopeng , Wang Xu , Zhang Baoxin , Cui Jinhan , Lu Xinpeng , Ren Chuan , Cai Weijia , Yu Xinghua
Published: April 2022

The current study investigated the effects of data augmentation, convolutional layers depth, and learning rate on inspection accuracy of a deep learning model which detects welding defects. The experimental results suggested that simultaneous use of these two methods improved the model's performance more than the sum of using each of the two methods alone. As the number of convolutional layers increases above 10, the network cannot extract defect features effectively, and the model's accuracy will decrease. Learning rate could significantly influence convergence rate and accuracy, and using an initial learning rate of 1e-4 and decaying it at epoch 250 could reduce the loss function and increase model accuracy.
Maxwell’s equations as mechanical law
Authors: Jens U Nöckel
Published: April 2022

Electrodynamics and special relativity are so deeply interconnected that it is difficult decide which of them is the logical consequence of the other, without running the risk of circular reasoning. Following the historical development by introducing electromagnetism phenomenologically first, this issue is not resolved but at best minimized, because even the Lorentz force law itself is fundamentally relativistic. Here we propose a derivation of Maxwell’s equations at a beginning graduate level with the goal of circumventing this difficulty. Based on prior work that establishes special relativity independently of any electrodynamic postulates, it is indeed possible to derive Maxwell’s equations from relativity by adding suitable assumptions. The contribution of the present work is to choose these assumptions in such a way that they can be regarded as extensions of the same postulates on which special-relativistic point-particle dynamics itself is based in the first place. The biggest leap is to extend the law of energy- and momentum conservation to the electromagnetic field itself. This hinges on the energy–momentum tensor, and the fact that the latter must account not only for the Lorentz force on a charge, but also for the forces exerted by that same charge on its environment.
Addendum: On stochastic Kaczmarz type methods for solving large scale systems of ill-posed equations (2022 Inverse Problems

38 025003)
Authors: Rabelo J C , Leitão A
Published: April 2022

We address the convergence analysis derived in (Rabelo et al 2022 Inverse Problems
38 025003) for the sPLWK method; a SGD type method for solving large scale systems of ill-posed equations. The assumption constraining the growth rate of the stopping index function

k

*

:
δ
↦

k

*

(

δ

)

∈
N

is removed; this assumption was needed in the proof of the semi-convergence result. The most important consequence of our findings is the fact that, what semi-convergence concerns, in the sPLWK method the growth rate of k*(δ), as δ goes to zero, is independent of the decay rate of the noise level. This is in strong contrast to the deterministic theory, where one needs additional assumptions of the type lim
δ→0‖δ‖2
k*(δ) = 0 for many iterative schemes, i.e., the stopping index should not grow to fast.
Perpendicular magnetic anisotropy and its voltage control in MgO/CoFeB/Mo/CoFeB/MgO junctions
Authors: Yamamoto Tatsuya , Ichinose Tomohiro , Uzuhashi Jun , Nozaki Takayuki , Ohkubo Tadakatsu , Yakushiji Kay , Tamaru Shingo , Kubota Hitoshi , Fukushima Akio , Hono Kazuhiro , Yuasa Shinji
Published: April 2022

We study the perpendicular magnetic anisotropy (PMA) in the MgO/CoFeB (CFB)/MgO junctions with an angstrom-thick Mo spacer layer separating the CFB layer. Perpendicularly magnetized CFB/Mo/CFB films are achieved for a wide range of CFB thicknesses, and a large PMA energy density of

>

0.3

mJ m−2 is demonstrated by tuning the thickness ratio of the two CFB layers as well as the thickness of the Mo spacer layer. The PMA in the MgO/CFB/Mo/CFB/MgO is controlled by a voltage applied across the junction, and a sign inversion in the voltage-controlled magnetic anisotropy effect is clearly observed between the ‘top free’ and ‘bottom free’ magnetic tunnel junctions, in which the CFB/Mo/CFB layers are fabricated on top and bottom of an MgO barrier layer, respectively. Nanostructural analyses reveal the difference in the morphology of the top free and bottom free magnetic tunnel junctions and also suggest that the flatness of CFB/MgO interface is rather important for improving the efficiency of the voltage-controlled magnetic anisotropy.
Tunable terahertz absorption modulation in graphene nanoribbon-assisted dielectric metamaterial
Authors: Dhriti K M , Kumar Chowdhary Ashish , Singh Chouhan Bhagwat , Sikdar Debabrata , Kumar Gagan
Published: April 2022

Designing metamaterial absorbers with tunable and broadband response with high modulation depth is crucial for application in switches, polarization sensitive devices, and optical filters. In this article, we report a tunable broadband metamaterial absorber in terahertz regime. The design comprises frustum shaped dielectric (SiO2) metamaterial structures on top of a one-dimensional period array of graphene nanoribbons (GNRs) deposited over the ultrathin metal-backed dielectric. For TM polarization, our design offers a near-perfect absorption in the range of 0.72 THz to 0.9 THz with 72.7

%

fractional bandwidth. On the contrary, we get a negligible absorption for the TE polarization of the incident light, thereby giving an absorption contrast ratio up to 20.5 dB. The excitation of plasmons in GNRs combined with resonance induced by the graphene-dielectric-metal cavity leads to nearly perfect broadband absorption for the TM polarized radiation. Further, modulation of the absorption spectrum has been achieved by changing graphene conductivity with the help of its Fermi energy. A theoretical model based on effective medium theory and transfer matrix method has been presented to validate absorption response for various Fermi energy values of the graphene. The figure of merit of our design can outperform some of the recently reported tunable metamaterial absorbers.
Approximating quantum thermodynamic properties using DFT
Authors: Zawadzki K , Skelt A H , D’Amico I
Published: April 2022

The fabrication, utilisation, and efficiency of quantum technology devices rely on a good understanding of quantum thermodynamic properties. Many-body systems are often used as hardware for these quantum devices, but interactions between particles make the complexity of related calculations grow exponentially with the system size. Here we explore and systematically compare ‘simple’ and ‘hybrid’ approximations to the average work and entropy variation built on static density functional theory concepts. These approximations are computationally cheap and could be applied to large systems. We exemplify them considering driven one-dimensional Hubbard chains and show that, for ‘simple’ approximations and low to medium temperatures, it pays to consider a good estimate of the Kohn–Sham Hamiltonian to approximate the driving Hamiltonian. Our results confirm that a ‘hybrid’ approach, requiring a very good approximation of the initial and, for the entropy, final states of the system, provides great improvements. This approach should be particularly efficient when many-body effects are not increased by the driving Hamiltonian.
Polarimetric imaging system based on double-layer prisms pair with polarizer coating and one camera
Authors: Yuan Tianyu , Dai Xiangjun , Yang Fujun , He Xiaoyuan
Published: April 2022

A novel polarimetric imaging system is proposed, which is based on one complementary metal-oxide-semiconductor (CMOS) camera and double-layer prisms pair. Four polarizers, whose axes were set at different angles and affixed to the four prisms. The CMOS camera is used to simultaneously record the intensity of the light passing through the prisms with four specific polarization information. An algorithm is adopted to align and correct parallax to generate accurate Stokes parameters. Indoor and outdoor experimental performances verify the effectiveness and high measurement accuracy of the proposed system.
Investigations in the tape-to-tape contact resistance and contact composition in superconducting CORC® wires
Authors: Phifer Virginia , Small Michael , Bradford Griffin , Weiss Jeremy , van der Laan Danko , Cooley Lance
Published: April 2022

Conductor on Round Core (CORC®) wires and cables, constructed from multiple layers of helically wound REBa2Cu3O7−δ
tapes, are a promising cable technology for high field magnet applications. An important feature of high-temperature superconductor cables is the ability to share current between conductors, allowing current to bypass drops in I
c and minimizing the risk of hot spot formation, which could lead to potential burnout in the superconductor. In contrast to stacked-tape cables, which have continuous contact between tapes, in CORC® the transfer points occur at discrete tape crossovers. The tape-to-tape contact resistance, R
c, plays a critical role in the current sharing capabilities and current distribution in cables. For the work reported here, special CORC® wires were manufactured using different winding parameters to investigate variations in R
c. Variations comprised inclusion of a lubricant, different lubricant conductivity, inclusion of pre-tinning, and heating briefly to melt the solder. Cables were first tested as straight lengths, followed by bending to a 10 cm diameter. In straight cables R
c values ranged from 1 to over 1000 μΩ cm2, depending on cabling parameters, with the highest values being found for cables made by the present ‘standard’ process. Bending the cables to a 10 cm diameter decreased R
c by a factor 2–5. Tinning with PbSn decreased R
c by three orders of magnitude compared to standard CORC® wires, and heat treating wires with tinned conductor resulted in only a small further decrease in R
c. Based on the measured R
c at an electric field of 1 μV cm−1 the resulting current transfer length between layers can range from a few millimeters to a tens of centimeters. Examination of contacts with a laser confocal microscope showed plastic deformation of the copper at the edges of the contact overlap area, apparently caused by thicker plating at tape edges digging into the copper of neighboring layers. These images reveal that only a fraction of the total contact surface may actually be touching when there is nothing to compensate for height differential. Images of the PbSn coated tapes indicated that application of solder produces a much more uniform contact surface and higher contact area. Furthermore, imaging of CORC® cross-sections confirmed that in the non-tinned cables there are many regions where tapes are not in contact, while in contrast the PbSn cable shows significantly more contact between the tapes. These different imaging techniques reveal that tape surface morphology is a significant parameter in determining R
c.
The microstructure and Ruppeiner geometry of charged anti-de Sitter black holes in Gauss–Bonnet gravity: from the critical point to the triple point
Authors: Wei Shao-Wen , Liu Yu-Xiao
Published: April 2022

Ruppeiner geometry has been successfully applied in the study of the black hole microstructure by combining with the small–large black hole phase transition, and the potential interactions among the molecular-like constituent degrees of freedom are uncovered. In this paper, we will extend the study to the triple point, where three black hole phases coexist acting as a typical feature of black hole systems quite different from the small–large black hole phase transition. For the six-dimensional charged Gauss–Bonnet anti-de Sitter black hole, we thoroughly investigate the swallow tail behaviors of the Gibbs free energy and the equal area laws. After obtaining the black hole triple point in a complete parameter space, we exhibit its phase structures both in the pressure–temperature and temperature–horizon radius diagrams. Quite different from the liquid–vapor phase transition, a double peak behavior is present in the temperature–horizon radius phase diagram. Then we construct the Ruppeiner geometry and calculate the corresponding normalized curvature scalar. Near the triple point, we observe multiple negatively divergent behaviors. Positive curvature scalar is observed for the small black hole with high temperature, which indicates that the repulsive interaction dominates among the microstructure. Furthermore, we consider the variation of the curvature scalar along the coexisting intermediate and large black hole curves. Combining with the observation for different fluids, the result suggests that this black hole system behaves more like the argon or methane. Our study provides a first and preliminary step towards understanding black hole microstructure near the triple point, as well as uncovering the particular properties of the Gauss–Bonnet gravity.
Efficient quantum private comparison protocol utilizing single photons and rotational encryption
Authors: Kou Tian-Yi , Che Bi-Chen , Dou Zhao , Chen Xiu-Bo , Lai Yu-Ping , Li Jian
Published: April 2022

As a branch of quantum secure multiparty computation, quantum private comparison is applied frequently in many fields, such as secret elections, private voting, and identification. A quantum private comparison protocol with higher efficiency and easier implementation is proposed in this paper. The private secrets are encoded as single polarized photons and then encrypted with a homomorphic rotational encryption method. Relying on this method and the circular transmission mode, we implement the multiplexing of photons, raising the efficiency of our protocol to 100%. Our protocol is easy to realize since only single photons, unitary operation, and single-particle measurement are introduced. Meanwhile, the analysis shows that our protocol is also correct and secure.
Validation of high voltage power supplies for the 1-inch photomultipliers of AugerPrime, the Pierre Auger Observatory upgrade
Authors: Anastasi G.A. , Buscemi M. , Aglietta M. , Caruso R. , Castellina A. , Costa S. , Gallian S. , Gorgi A. , Guardone N. , Lombardo C. , Wheadon R. , Zampieri A.
Published: April 2022

In the framework of the upgrade of the Pierre Auger
Observatory, a new high voltage module is being employed for the
power supply of the 1-inch photomultiplier added to each
water-Cherenkov detector of the surface array with the aim of
increasing the dynamic range of the measurements. This module is
located in a dedicated box near the electronics and comprises a low
consumption DC-DC converter hosted inside an aluminum box. All the
modules have undergone specific tests to verify their reliability in
the extreme environmental conditions of the Argentinian pampa. In
this paper, we describe the validation procedure and the facility
developed to this aim. The successful results of the tests on the
HVPS modules are presented and discussed.
Substantial carbon loss respired from a corn–soybean agroecosystem highlights the importance of careful management as we adapt to changing climate
Authors: Moore Caitlin E , Gibson Christy D , Miao Guofang , Dracup Evan C , Gomez-Casanovas Nuria , Masters Michael D , Miller Jesse , C von Haden Adam , Meyers Tilden , DeLucia Evan H , Bernacchi Carl J
Published: April 2022

Understanding agroecosystem carbon (C) cycle response to climate change and management is vital for maintaining their long-term C storage. We demonstrate this importance through an in-depth examination of a ten-year eddy covariance dataset from a corn–corn–soybean crop rotation grown in the Midwest United States. Ten-year average annual net ecosystem exchange (NEE) showed a net C sink of −0.39 Mg C ha−1 yr−1. However, NEE in 2014 and 2015 from the corn ecosystem was 3.58 and 2.56 Mg C ha−1 yr−1, respectively. Most C loss occurred during the growing season, when photosynthesis should dominate and C fluxes should reflect a net ecosystem gain. Partitioning NEE into gross primary productivity (GPP) and ecosystem respiration (ER) showed this C ‘burp’ was driven by higher ER, with a 51% (2014) and 57% (2015) increase from the ten-year average (15.84 Mg C ha−1 yr−1). GPP was also higher than average (16.24 Mg C ha−1 yr−1) by 25% (2014) and 37% (2015), but this was not enough to offset the C emitted from ER. This increased ER was likely driven by enhanced soil microbial respiration associated with ideal growing season climate, substrate availability, nutrient additions, and a potential legacy effect from drought.
Net carbon accounting and reporting are a barrier to understanding the mitigation value of forest protection in developed countries
Authors: Mackey Brendan , Moomaw William , Lindenmayer David , Keith Heather
Published: April 2022

Meeting the Paris Agreement global warming target requires deep and rapid cuts in CO2 emissions as well as removals from the atmosphere into land sinks, especially forests. While international climate policy in the land sector does now recognize forest protection as a mitigation strategy, it is not receiving sufficient attention in developed countries even though they experience emissions from deforestation as well as from logging of managed forests. Current national greenhouse gas inventories obscure the mitigation potential of forest protection through net carbon accounting between the fossil fuel and the land sectors as well as within the different categories of the land. This prevents decision-makers in national governments, the private sector and civil society having access to all the science-based evidence needed to evaluate the merits of all mitigation strategies. The consequences of net carbon accounting for global policy were investigated by examining annual inventory reports of four high forest cover developed countries (Australia, Canada, USA, and Russia). Net accounting between sectors makes a major contribution to meeting nationally determined contributions with removals in Forest Land offsetting between 14% and 38% of the fossil fuel emissions for these countries. Analysis of reports for Australia at a sub-national level revealed that the State of Tasmania delivered negative emissions due to a change in forest management—a large and rapid drop in native forest logging—resulting in a mitigation benefit of ∼22 Mt CO2-e yr–1 over the reported period 2011/12–2018/19. This is the kind of outcome required globally to meet the Paris Agreement temperature goal. All CO2 emissions from, and atmospheric removals into, forest ecosystem carbon stocks now matter and should be counted and credited to achieve the deep and rapid cuts in emissions needed over the coming decades. Accounting and reporting systems therefore need to show gains and losses of carbon stocks in each reservoir. Changing forest management in naturally regenerating forests to avoid emissions from harvesting and enabling forest regrowth is an effective mitigation strategy that can rapidly reduce anthropogenic emissions from the forest sector and simultaneously increase removals of CO2 from the atmosphere.
Mesoscopic Möbius ladder lattices as non-Hermitian model systems
Authors: Ryu Jung-Wan , Hentschel Martina
Published: April 2022

While classic quantum chaos originated from the idea to set into context nonlinear physics and Hermitian quantum mechanics, non-Hermitian models have enhanced the field in recent years. At the same time, low-dimensional effective matrix models have proven to be a powerful tool in accessing the physical properties of a system in a semiquantitative manner. Here, we focus on two realizations of non-Hermitian physics in mesoscopic systems. First, we consider spiral optical microcavities in which the asymmetric scattering between whispering gallery modes induces the non-Hermitian behaviour. Second, for parity-time (PT) symmetric ladder lattices we compare circular and Möbius geometries. We find the effective coupling between even and odd parity modes to be symmetric but complex in a microscopically derived 2 × 2 matrix model, resulting in non-Hermitian behaviour as well. Most importantly, the Möbius topology acts like a scatterer that induces a qualitatively new form of (avoided) level crossing—a PT-broken phase terminated by exceptional points—resulting from the symmetric but non-Hermitian coupling.
Reproducibility and reporting, the routes to progress in breath research—highlights from the Breath Biopsy Conference 2021
Authors: Lawson Jonathan L D , Nakhleh Morad K , Smolinska Agnieszka
Published: April 2022

With the continued presence of COVID-19 worldwide, it has been a challenge for the breath research community to progress with clinical studies and travel restrictions have also limited the opportunities to meet up, share ideas and celebrate the latest advances. The Breath Biopsy Conference 2021 offered the chance to catch up with the latest breath research and to share progress that researchers in the community have been able to make in these difficult times. Limited opportunities for clinical research have led many in the field to look more closely at different methods for breath collection and have contributed to the growing calls for consistent standards in how results are reported, shared and even how breath studies themselves are carried out. As such, standardization was a key theme for this year’s event and featured prominently in the keynotes, discussions and throughout many of the presentations. With over 900 registrants, almost 400 live attendees and 16 speakers, the Breath Biopsy Conference continues to bring together breath research leaders from around the world. This article provides an overview of the highlights from this event.
The significance of nanoparticles in brain cancer diagnosis and treatment: modeling and simulation
Authors: Badawi Mohamed I , Hafez Karim S
Published: April 2022

A numerical analysis of specific absorption rate (SAR) and temperature distributions in a realistic human head model is presented in this study. The key challenge is to rise cancer temperature to an optimal temperature without heating nearby healthy tissues. The model’s uniqueness is that it captures the effect of nanoparticles on both brain cancer diagnosis and treatment. A realistic human head model with a cancerous brain segmented from 2D magnetic resonance imaging (MRI) gained from an actual patient using 3D Slicer, modeled, and simulated using CST-Microwave Studio, and illuminated by Archimedes spiral antenna. At frequencies of 2450 MHz and 915 MHz, the model simulated the absence and presence of various nanoparticles. The obtained results suggest that when using nanoparticles, it is possible to achieve sufficient energy deposition and temperature rise to therapeutic values (greater than 42 °C) in brain cancers using the proposed noninvasive hyperthermia system at 915 MHz frequency, especially for gold nanoparticles, without harming surrounding healthy tissue. Our research might pave the way for a clinical applicator prototype that can heat brain cancer.
Classifying the 2021 ‘Ahrtal’ flood event using hermeneutic interpretation, natural language processing, and instrumental data analyses
Authors: Kahle Michael , Kempf Michael , Martin Brice , Glaser Rüdiger
Published: April 2022

Extreme weather events and severe flash floods during July 2021 caused numerous deaths and massive ecological disasters across Europe. The regionally overstrained environmental and socio-cultural resilience triggered an intensive discussion about cause and effect, responsibilities and public denouncement, and the financial consequences of climate-induced extreme events. In this article we analyze the flood event by four methodological approaches: (1) hermeneutics, with an analog interpretation of printed newspapers and sources; (2) text mining and natural language processing of digital newspaper articles available online; (3) precipitation and discharge models based on instrumental data; and (4) how the findings can be linked to the historical extreme floods of 1804 and 1910, based on documentary source analysis. These four approaches are used to compare and evaluate their consistency by tracking the course, consequences, and aftermaths of the flood disaster. The study shows a high consistency between the analog, digital, and instrumental data analysis. A combination of multidisciplinary methods and their application to historical events enables the evaluation of modern events. It enables to answer the question of return periods and intensities, which are indispensable for today’s risk assessments and their social contextualization, a desideratum in historical and modern climatology.
Laser-induced microjet-assisted ablation for high-quality microfabrication
Authors: Guo Yang , Qiu Pei , Xu Shaolin , Cheng Gary J
Published: April 2022

Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m s−1 in its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation (LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.
Ketorolac tromethamine represses senescence in aging articular chondrocytes
Authors: Zhang Wei , Mei Rong , Wu Shuxuan
Published: April 2022

The present study aims to explore the potential function of ketorolac tromethamine in treating osteoarthritis (OA) by examining its effects on interleukin-1β (IL-1β)-triggered cellular senescence in chondrocytes. More β-galactosidase (SA-β-Gal) positively stained cells, promoted cell fraction in the G0/G1 phase, increased release of matrix metalloproteinase (MMP)-3 and MMP-13, and upregulated cellular senescence-related genes (p21 and p53) were observed in IL-1β-challenged HC-A cells, all of which were significantly reversed by 25 and 50 mg/mL ketorolac tromethamine. Furthermore, the upregulated cyclooxygenase-2 (COX-2) and elevated release of prostaglandin E2 (PGE2) in IL-1β- challenged HC-A cells were dramatically repressed by ketorolac tromethamine. Lastly, the inhibitory effects of ketorolac tromethamine on the activation of β-galactosidase and the upregulation of p21 and p53 were greatly abolished by the overexpression of COX-2. Collectively, ketorolac tromethamine repressed cellular senescence in aging articular chondrocytes by inhibiting COX-2.
Noncanonical functions of PIWIL1/piRNAs in animal male germ cells and human diseases
Authors: Wang Xin , Gou Lan-Tao , Liu Mo-Fang
Published: April 2022

PIWI proteins and PIWI-interacting RNAs (piRNAs) are specifically expressed in animal germlines and play essential roles during gametogenesis in animals. The primary function of PIWI/piRNAs is known to silence transposable elements for protecting genome integrity in animal germlines, while their roles beyond silencing transposons are also documented by us and others. In particular, we show that mouse PIWIL1 (MIWI)/piRNAs play a dual role in regulating protein-coding genes in mouse spermatids through interacting with different protein factors in a developmental stage-dependent manner, including translationally activating a subset of AU-rich element-containing mRNAs in round spermatids and inducing massive mRNA degradation in late spermatids. We further show that MIWI is eliminated through the ubiquitin-26S proteasome pathway during late spermiogenesis. By exploring the biological function of MIWI ubiquitination by APC/C, we identified ubiquitination-deficient mutations in human PIWIL1 of infertile men and further established their causative role in male infertility in mouse model, supporting PIWIL1 as a human male infertility-relevant gene. Additionally, we reported that PIWIL1, aberrantly induced in human tumors, functions as an oncoprotein in a piRNA-independent manner in cancer cells. In the current review, we summarize our latest findings regarding the roles and mechanisms of PIWIL1 and piRNAs in mouse spermatids and human diseases, and discuss the related works in the field.
Overall Vertical Transmission of Hepatitis C Virus, Transmission Net of Clearance, and Timing of Transmission
Authors: Ades Anthony E , Gordon Fabiana , Scott Karen , Collins Intira J , Claire Thorne , Pembrey Lucy , Chappell Elizabeth , Mariné-Barjoan Eugènia , Butler Karina , Indolfi Giuseppe , Gibb Diana M , Judd Ali
Published: April 2022

Background

It is widely accepted that the risk of hepatitis C virus (HCV) vertical transmission (VT) is 5%–6% in monoinfected women, and that 25%–40% of HCV infection clears spontaneously within 5 years. However, there is no consensus on how VT rates should be estimated, and there is a lack of information on VT rates “net” of clearance.

Methods

We reanalyzed data on 1749 children in 3 prospective cohorts to obtain coherent estimates of overall VT rate and VT rates net of clearance at different ages. Clearance rates were used to impute the proportion of uninfected children who had been infected and then cleared before testing negative. The proportion of transmission early in utero, late in utero, and at delivery was estimated from data on the proportion of HCV RNA positive within 3 days of birth, and differences between elective cesarean and nonelective cesarean deliveries.

Results

Overall VT rates were 7.2% (95% credible interval [CrI], 5.6%–8.9%) in mothers who were human immunodeficiency virus (HIV) negative and 12.1% (95% CrI, 8.6%–16.8%) in HIV-coinfected women. The corresponding rates net of clearance at 5 years were 2.4% (95% CrI, 1.1%–4.1%), and 4.1% (95% CrI, 1.7%–7.3%). We estimated that 24.8% (95% CrI, 12.1%–40.8%) of infections occur early in utero, 66.0% (95% CrI, 42.5%–83.3%) later in utero, and 9.3% (95% CrI, 0.5%–30.6%) during delivery.

Conclusions

Overall VT rates are about 24% higher than previously assumed, but the risk of infection persisting beyond age 5 years is about 38% lower. The results can inform design of trials of interventions to prevent or treat pediatric HCV infection, and strategies to manage children exposed in utero.
The Structural and Functional Correlates of Frailty in Persons With Human Immunodeficiency Virus
Authors: Strain Jeremy F , Cooley Sarah , Kilgore Collin , Nelson Brittany , Doyle John , Thompson Regina , Westerhaus Elizabeth , Petersen Kalen J , Wisch Julie , Ances Beau M
Published: April 2022

Background

Persons with HIV (PWH) are at increased risk of frailty, a clinically recognizable state of increased vulnerability resulting from aging-associated decline in multiple physiologic systems. Frailty is often defined by the Fried criteria, which includes subjective and objective standards concerning health resiliency. However, these frailty metrics do not incorporate cognitive performance or neuroimaging measures.

Methods

We compared structural (diffusion tensor imaging [DTI]) and functional (cerebral blood flow [CBF]) neuroimaging markers in PWH with frailty and cognitive performance. Virologically controlled PWH were dichotomized as either frail (≥3) or nonfrail (<3) using the Fried criteria. Cognitive Z-scores, both domain (executive, psychomotor speed, language, and memory) and global, were derived from a battery of tests. We identified three regions of reduced CBF, based on a voxel-wise comparison of frail PWH compared with nonfrail PWH. These clusters (bilateral frontal and posterior cingulate) were subsequently used as seed regions of interest (ROIs) for DTI probabilistic white matter tractography.

Results

White matter integrity connecting the ROIs was significantly decreased in frail compared with nonfrail PWH. No differences in cognition were observed between frail and nonfrail PWH. However, reductions in white matter integrity among these ROIs was significantly associated with worse psychomotor speed and executive function across the entire cohort.

Conclusions

We conclude that frailty in PWH can lead to structural and functional brain changes, including subtle changes that are not detectable by standard neuropsychological tests. Multimodal neuroimaging in conjunction with frailty assessment could identify pathological brain changes observed in PWH.