bluuebunny/crossref_metadata_2025 huggingface dataset:
Shrubs alter alpha and beta diversity of soil fauna in a semiarid grassland
Authors: Gao Haining , Li Caixia , Jiao Yang , Zhang Yong , Feng Qi
Published: January 2023

Shrubs are widely distributed in semi-arid and arid ecosystems. Understanding shrub effects on alpha and beta diversity of soil fauna in arid and semiarid ecosystems could lead to promotion of biodiversity conservation and sustainable management. Yet the extent to which shrubs can influence beta diversity of soil fauna and different body size in arid and semiarid ecosystems is unknown. An investigation of soil fauna, macrofauna, and mesofauna beneath shrub canopy and in open spaces was conducted in the Donddashan Nature Reserve (a semiarid grassland ecosystem in China). Shrubs significantly increased the alpha diversity (richness and Shannon index), but significantly decreased the beta diversity and the nestedness component. Moreover, shrub effects differed among soil fauna of different body size. Shrubs significantly increased the abundance and Shannon index of mesofauna, whereas there were no significant effects on macrofauna between shrubs and open spaces. Shrubs significantly decreased the beta diversity of mesofauna, but significantly increased beta diversity and the turnover component of macrofauna. Piecewise structural equation modelling (SEM) showed that shrubs had an indirect effect on soil fauna diversity through mesofauna diversity. Results highlighted the crucial role that shrubs have in maintaining alpha diversity of soil fauna in arid ecosystem, and also demonstrated the divergent shrub effects on beta diversity of soil fauna, mesofauna, and macrofauna. This suggests a need to examine different taxonomic groups to gain a better understanding of ecological consequences of shrubs.
Ecological marginalization is widespread and increases extinction risk in mammals
Authors: Britnell Jake Alan , Zhu Yichun , Kerley Graham Ian Holme , Shultz Susanne
Published: January 2023

Human land-use results in widespread range change across taxa. Anthropogenic pressures can result in species’ realized niches expanding, shifting, or contracting. Marginalization occurs when contraction constrains species to the geographic or ecological extremes of their historic niche. Using 4,785 terrestrial mammal species, we show that range contraction results in niche space and habitat diversity loss. Additionally, ecological marginalization is a common consequence of range contraction caused by human land use change. Remnant populations become located in the climatic and topographic extremes of their historic niche that are more likely to be at the periphery of their historic niche at greater distances from historic niche centroids. This ecological marginalization is associated with poor performance and increased extinction risk independent of geographic range loss. Range loss and marginalization may create a “double whammy” in vulnerable groups, such as large-bodied species and species with small geographical range size. Our results reveal a hitherto unrecognized conservation threat that is vital to incorporate into conservation assessment and management.
N-doped carbon–iron heterointerfaces for boosted electrocatalytic active and selective ammonia production
Authors: Zhang Shuo , Li Miao , Li Jiacheng , Song Qinan , Liu Xiang
Published: January 2023

The electrochemical conversion of waste nitrate (NO
3
−
) to valuable ammonia (NH
3
) is an economical and environmentally friendly technology for sustainable NH
3
production. It is beneficial for environmental nitrogen pollution management and is also an appealing alternative to the current Haber–Bosch process for NH
3
production. However, owing to the competing hydrogen evolution reaction, it is necessary to design highly efficient and stable electrocatalysts with high selectivity. Herein, we report a rational design of Fe nanoparticles wrapped in N-doped carbon (Fe@N
10
-C) as a high NH
3
selective and efficient electrocatalyst using a metal–organic framework precursor. We constructed a catalyst with new active sites by doping with nitrogen, which activated neighboring carbon atoms and enhanced metal-to-carbon electron transfer, resulting in high catalytic activity. These doped N sites play a key role in the NO
3
−
electroreduction. As a result, the Fe@N
10
-C nanoparticles with optimal doping of N demonstrated remarkable performance, with a record-high NO
3
−
removal capacity of 125.8 ± 0.5 mg N g
cat
−1
h
−1
and nearly 100 % (99.7 ± 0.1%) selectivity. The catalyst also delivers an impressive NH
3
production rate of 2647.7 μg h
−1
cm
−2
and high faradaic efficiency of 91.8 ± 0.1%. This work provides a new route for N-doped carbon–iron catalysis application and paves the way for addressing energy and environmental issues.
CPR5-mediated nucleo-cytoplasmic localization of IAA12 and IAA19 controls lateral root development during abiotic stress
Authors: Nam Heejae , Han Soeun , Lee Seungchul , Nam Hoyoung , Lim Hojun , Lee Garam , Cho Hyun Seob , Dang Tuong Vi Thi , Choi Sangkyu , Lee Myeong Min , Hwang Ildoo
Published: January 2023

Plasticity of the root system architecture (RSA) is essential in enabling plants to cope with various environmental stresses and is mainly controlled by the phytohormone auxin. Lateral root development is a major determinant of RSA. Abiotic stresses reduce auxin signaling output, inhibiting lateral root development; however, how abiotic stress translates into a lower auxin signaling output is not fully understood. Here, we show that the nucleo-cytoplasmic distribution of the negative regulators of auxin signaling AUXIN/INDOLE-3-ACETIC ACID INDUCIBLE 12 (AUX/IAA12 or IAA12) and IAA19 determines lateral root development under various abiotic stress conditions. The cytoplasmic localization of IAA12 and IAA19 in the root elongation zone enforces auxin signaling output, allowing lateral root development. Among components of the nuclear pore complex, we show that CONSTITUTIVE EXPRESSOR OF PATHOGENESIS-RELATED GENES 5 (CPR5) selectively mediates the cytoplasmic translocation of IAA12/19. Under abiotic stress conditions,
CPR5
expression is strongly decreased, resulting in the accumulation of nucleus-localized IAA12/19 in the root elongation zone and the suppression of lateral root development, which is reiterated in the
cpr5
mutant. This study reveals a regulatory mechanism for auxin signaling whereby the spatial distribution of AUX/IAA regulators is critical for lateral root development, especially in fluctuating environmental conditions.
Mechanistic model for booster doses effectiveness in healthy, cancer, and immunosuppressed patients infected with SARS-CoV-2
Authors: Voutouri Chrysovalantis , Hardin C. Corey , Naranbhai Vivek , Nikmaneshi Mohammad R. , Khandekar Melin J. , Gainor Justin F. , Stylianopoulos Triantafyllos , Munn Lance L. , Jain Rakesh K.
Published: January 2023

SARS-CoV-2 vaccines are effective at limiting disease severity, but effectiveness is lower among patients with cancer or immunosuppression. Effectiveness wanes with time and varies by vaccine type. Moreover, previously prescribed vaccines were based on the ancestral SARS-CoV-2 spike-protein that emerging variants may evade. Here, we describe a mechanistic mathematical model for vaccination-induced immunity. We validate it with available clinical data and use it to simulate the effectiveness of vaccines against viral variants with lower antigenicity, increased virulence, or enhanced cell binding for various vaccine platforms. The analysis includes the omicron variant as well as hypothetical future variants with even greater immune evasion of vaccine-induced antibodies and addresses the potential benefits of the new bivalent vaccines. We further account for concurrent cancer or underlying immunosuppression. The model confirms enhanced immunogenicity following booster vaccination in immunosuppressed patients but predicts ongoing booster requirements for these individuals to maintain protection. We further studied the impact of variants on immunosuppressed individuals as a function of the interval between multiple booster doses. Our model suggests possible strategies for future vaccinations and suggests tailored strategies for high-risk groups.
A reconstruction of parasite burden reveals one century of climate-associated parasite decline
Authors: Wood Chelsea L. , Welicky Rachel L. , Preisser Whitney C. , Leslie Katie L. , Mastick Natalie , Greene Correigh , Maslenikov Katherine P. , Tornabene Luke , Kinsella John M. , Essington Timothy E.
Published: January 2023

Long-term data allow ecologists to assess trajectories of population abundance. Without this context, it is impossible to know whether a taxon is thriving or declining to extinction. For parasites of wildlife, there are few long-term data—a gap that creates an impediment to managing parasite biodiversity and infectious threats in a changing world. We produced a century-scale time series of metazoan parasite abundance and used it to test whether parasitism is changing in Puget Sound, United States, and, if so, why. We performed parasitological dissection of fluid-preserved specimens held in natural history collections for eight fish species collected between 1880 and 2019. We found that parasite taxa using three or more obligately required host species—a group that comprised 52% of the parasite taxa we detected—declined in abundance at a rate of 10.9% per decade, whereas no change in abundance was detected for parasites using one or two obligately required host species. We tested several potential mechanisms for the decline in 3+-host parasites and found that parasite abundance was negatively correlated with sea surface temperature, diminishing at a rate of 38% for every 1 °C increase. Although the temperature effect was strong, it did not explain all variability in parasite burden, suggesting that other factors may also have contributed to the long-term declines we observed. These data document one century of climate-associated parasite decline in Puget Sound—a massive loss of biodiversity, undetected until now.
Towards a World Wide Web without digital inequality
Authors: Chaqfeh Moumena , Asim Rohail , AlShebli Bedoor , Zaffar Muhammad Fareed , Rahwan Talal , Zaki Yasir
Published: January 2023

The World Wide Web (WWW) empowers people in developing regions by eradicating illiteracy, supporting women, and generating economic opportunities. However, their reliance on limited bandwidth and low-end phones leaves them with a poorer browsing experience compared to privileged users across the digital divide. To evaluate the extent of this phenomenon, we sent participants to 56 cities to measure the cost of mobile data and the average page load time. We found the cost to be orders of magnitude greater, and the average page load time to be four times slower, in some locations compared to others. Analyzing how popular webpages have changed over the past years suggests that they are increasingly designed with high processing power in mind, effectively leaving the less fortunate users behind. Addressing this digital inequality through new infrastructure takes years to complete and billions of dollars to finance. A more practical solution is to make the webpages more accessible by reducing their size and optimizing their load time. To this end, we developed a solution called Lite-Web and evaluated it in the Gilgit-Baltistan province of Pakistan, demonstrating that it transforms the browsing experience of a Pakistani villager using a low-end phone to almost that of a Dubai resident using a flagship phone. A user study in two high schools in Pakistan confirms that the performance gains come at no expense to the pages’ look and functionality. These findings suggest that deploying Lite-Web at scale would constitute a major step toward a WWW without digital inequality.
Self-organized sulfide-driven traveling pulses shape seagrass meadows
Authors: Ruiz-Reynés Daniel , Mayol Elvira , Sintes Tomàs , Hendriks Iris E. , Hernández-García Emilio , Duarte Carlos M. , Marbà Núria , Gomila Damià
Published: January 2023

Seagrasses provide multiple ecosystem services and act as intense carbon sinks in coastal regions around the globe but are threatened by multiple anthropogenic pressures, leading to enhanced seagrass mortality that reflects in the spatial self-organization of the meadows. Spontaneous spatial vegetation patterns appear in such different ecosystems as drylands, peatlands, salt marshes, or seagrass meadows, and the mechanisms behind this phenomenon are still an open question in many cases. Here, we report on the formation of vegetation traveling pulses creating complex spatiotemporal patterns and rings in Mediterranean seagrass meadows. We show that these structures emerge due to an excitable behavior resulting from the coupled dynamics of vegetation and porewater hydrogen sulfide, toxic to seagrass, in the sediment. The resulting spatiotemporal patterns resemble those formed in other physical, chemical, and biological excitable media, but on a much larger scale. Based on theory, we derive a model that reproduces the observed seascapes and predicts the annihilation of these circular structures as they collide, a distinctive feature of excitable pulses. We show also that the patterns in field images and the empirically resolved radial profiles of vegetation density and sediment sulfide concentration across the structures are consistent with predictions from the theoretical model, which shows these structures to have diagnostic value, acting as a harbinger of the terminal state of the seagrass meadows prior to their collapse.
Microbiome influencers of checkpoint blockade–associated toxicity
Authors: Wang Yinghong , Jenq Robert R. , Wargo Jennifer A. , Watowich Stephanie S.
Published: January 2023

Immunotherapy has greatly improved cancer outcomes, yet variability in response and off-target tissue damage can occur with these treatments, including immune checkpoint inhibitors (ICIs). Multiple lines of evidence indicate the host microbiome influences ICI response and risk of immune-related adverse events (irAEs). As the microbiome is modifiable, these advances indicate the potential to manipulate microbiome components to increase ICI success. We discuss microbiome features associated with ICI response, with focus on bacterial taxa and potential immune mechanisms involved in irAEs, and the overall goal of driving novel approaches to manipulate the microbiome to improve ICI efficacy while avoiding irAE risk.
Axisymmetric, stationary collisionless gas clouds trapped in a Newtonian potential
Authors: Gabarrete Carlos , Sarbach Olivier
Published: January 2023

The properties of an axisymmetric, stationary gas cloud surrounding a massive central object are discussed. It is assumed that the gravitational field is dominated by the central object which is modeled by a nonrelativistic rotationally-symmetric potential. Further, we assume that the gas consists of collisionless, identical massive particles that follow bound orbits in this potential. Several models for the one-particle distribution function are considered and the essential formulae that describe the relevant macroscopical observables, such as the particle and energy densities, pressure tensor, and the kinetic temperature are derived. The asymptotic decay of the solutions at infinity is discussed and we specify configurations with finite total mass, energy and (zero or non-zero) angular momentum. Finally, our configurations are compared to their hydrodynamic analogs. In an accompanying paper, the equivalent general relativistic problem is discussed, where the central object consists of a Schwarzschild black hole.
Axisymmetric, stationary collisionless gas configurations surrounding Schwarzschild black holes
Authors: Gabarrete Carlos , Sarbach Olivier
Published: January 2023

The properties of a stationary gas cloud surrounding a black hole are discussed, assuming that the gas consists of collisionless, identical massive particles that follow spatially bound geodesic orbits in the Schwarzschild spacetime. Several models for the one-particle distribution function are considered, and the essential formulae that describe the relevant macroscopic observables, like the current density four-vector and the stress–energy–momentum tensor are derived. This is achieved by rewriting these observables as integrals over the constants of motion and by a careful analysis of the range of integration. In particular, we provide configurations with finite total mass and angular momentum. Differences between these configurations and their nonrelativistic counterparts in a Newtonian potential are analyzed. Finally, our configurations are compared to their hydrodynamic analogues, the ‘polish doughnuts’.
Possible enhancements of collective flow anisotropy induced by uncertainty relation for fluid element
Authors: de Matos Gyell Gonçalves , Kodama Takeshi , Koide Tomoi
Published: January 2023

In the stochastic formulation of viscous hydrodynamics, the velocity of a fluid element fluctuates satisfying a similar relation to the quantum-mechanical uncertainty relation. Using a non-relativistic toy model, we show that the presence of a velocity fluctuation increases the local anisotropy of the momentum distributions of produced hadrons and, consequently, the collective flow parameters such as v
2 are enhanced.
Probing electron-phonon and phonon-phonon coupling in type-II Dirac semi-metal NiTe2 via temperature-dependent Raman spectroscopy
Authors: James Minna Theres , Mandal Shoubhik , Sebastian Nirmal K , Mishra Pramita , Ganesan R , Kumar P S Anil
Published: January 2023

We report the temperature-dependent structural characterization of type-II Dirac semimetal NiTe2 in the form of a bulk single crystal and a nanoflake (200 nm thick). Detailed x-ray diffraction study along with Rietveld refinement analysis reveals superior crystallinity and linear thermal expansion coefficient (α

T
) of 5.56 × 10−6 and 22.5 × 10−6 K−1 along a or b and c lattice directions, respectively. Temperature evolution of Raman spectra shows non-linear variations in the phonon frequency and full-width half maxima of the out-of-plane A

1
g

and in-plane E
g
modes. Raman mode E

2
g

1

, corresponding to an in-plane vibration, disappears on decreasing the thickness from bulk to nanoflake. Quantitative analysis with anharmonic model yields dominating electron-phonon interaction over phonon-phonon interaction mediated by three- and four-phonon processes.
Flowthrough of 239PU and 55FE during RNA extraction
Authors: Manglass Lisa M , Vogel Charlotte M , Wintenberg Molly , Blenner Mark A , Martinez Nicole E
Published: January 2023

Analysis of gene expression has become an important tool in understanding low-dose effect mechanisms of ionizing radiation at the cellular level. Metal binding to nucleic acids needs to be considered when interpreting these results, as some radioactive metals, particularly actinides, may produce free radicals and cause oxidative stress damage via chemical means at rates much higher than free radical formation related to their radiological properties. Bacteria exposed in situ to low dose rates of plutonium-239 (239Pu) and iron-55 (55Fe) were previously analysed for gene expression. The work herein was motivated by an interest in more precisely identifying the distribution of radionuclides in these bacteria as well as the practical need to ensure appropriate transport and handling of the associated ribonucleic acid (RNA) extractions. RNA extractions were performed on bacteria growth media with and without bacteria cells (i.e. with and without RNA) at several different concentrations of 239Pu and 55Fe to inform the level of specificity of the extraction membrane as well as provide insight into internal (uptake) vs external (sorption) accumulation of these radionuclides in bacteria cells. Results of the study suggest that 239Pu and 55Fe detected in RNA extraction samples during long term cell studies is the result of binding to RNA prior to the time of extraction, as opposed to flow through or binding after cell lysis, and it highlights the practical importance of nucleic acid sample characterization to radiation protection more generally.
Developing a geological disaster monitoring system based on electrical prospecting
Authors: Wu Zhen , Deng Ming , Chen Guangyuan , Liu Yongdong , Zhang Qisheng , Guo Linyan
Published: January 2023

The functions and performances of current geological disaster monitoring systems have significantly improved in recent years. However, they still possess certain shortcomings, such as lack of deep monitoring functions and being affected by weather, atmosphere, and light. This study aims to combine electrical prospecting with geological disaster monitoring to develop an improved system. The proposed system has a high level of data gathering accuracy and involves deep monitoring. It is not easily affected by natural factors, such as the weather. We designed circuits for the high-precision data acquisition, high-voltage power transmission, and main control and developed an acquisition and monitoring software, which provides adequate technical support for geological disaster monitoring. The system was used to monitor the Lannitan landslide. Our results indicated that the proposed geological disaster monitoring system had stable functionality, high acquisition accuracy, simple operation of the human‒computer interface, and remote monitoring, meeting the requirements for geological disaster monitoring.
Super-resolution reconstruction of ultrasonic Lamb wave TFM image via deep learning
Authors: Zhang Wenjing , Chai Xiaodong , Zhu Wenfa , Zheng Shubin , Fan Guopeng , Li Zaiwei , Zhang Hui , Zhang Hanfei
Published: January 2023

Under the same detection frequency and depth, when the center spacing of multiple defects is less than the resolution threshold determined by the Rayleigh criterion, it is challenging to achieve super-resolution imaging of multiple defects using the ultrasonic total focusing method (TFM). A multilevel deep learning network is proposed as a super-resolution reconstruction method for ultrasonic Lamb wave TFM images. The first-level network is a detection network that uses a Resnet50 with more convolutional layers to improve the linear expression capabilities of the neural network. It introduces residual structure to solve low accuracy issues of multi-convolutional layers so that the Resnet50 can accurately detect defects from TFM images. The second-level network is a super-resolution reconstruction network that uses a Deeplab v3+ with a dilated convolutional layer. It controls the receptive field without changing the image feature size of the TFM image. With this model, a super-resolution reconstruction of multiple defects with a center spacing less than the resolution threshold is realized by extracting the detailed features of defects in the TFM image. Experimental results show that when the defect center spacing is greater than the resolution threshold determined by the Rayleigh criterion, the super-resolution reconstruction method improves the calculation accuracy of the defect center spacing by 4.7% and the calculation accuracy of the defect area by 93.7% compared with TFM. When the defect spacing is less than the resolution threshold, the method can still identify and accurately calculate the center spacing of multiple defects.
Ultraviolet photodetector based on RbCu2I3 microwire
Authors: An Hong-Xiang , Qiao Bao-Shi , Zhang Zhi-Hong , Lian Zhen-Dong , Wei Zhipeng , Li Xiao-Shuang , Zeng Qing-Guang , Wang Bo , Ng Kar Wei , Wang Shuang-Peng
Published: January 2023

Copper-based halide perovskites have shown great potential in lighting and photodetection due to their excellent photoelectric properties, good stability and lead-free nature. However, as an important piece of copper-based perovskites, the synthesis and application of RbCu2I3 have never been reported. Here, we demonstrate the synthesis of high-quality RbCu2I3 microwires (MWs) by a fast-cooling hot saturated solution method. The prepared MWs exhibit an orthorhombic structure with a smooth surface. Optical measurements show the RbCu2I3 MWs have a sharp ultraviolet absorption edge with 3.63 eV optical band gap and ultra-large stokes shift (300 nm) in photoluminescence. The subsequent photodetector based on a single RbCu2I3 MW shows excellent ultraviolet detection performance. Under the 340 nm illumination, the device shows a specific detectivity of 5.0 × 109 Jones and a responsivity of 380 mA·W−1. The synthesis method and physical properties of RbCu2I3 could be a guide to the future optoelectronic application of the new material.
Ultrafast high-temperature sintering and thermoelectric properties of n-doped Mg2Si
Authors: Boldrini Stefano , Ferrario Alberto , Fasolin Stefano , Miozzo Alvise , Barison Simona
Published: January 2023

Ultrafast high-temperature sintering (UHS) is a recently proposed technique able to synthesize and sinter dense materials within seconds. Although UHS has already proved its effectivity with a large set of materials, spanning from refractory ceramics to complex metal alloys, any application to thermoelectric materials is today still lacking. Mg2Si is a well-established thermoelectric material. It is based on wide available non-critical raw materials, it is non-toxic, lightweight and it expresses its best thermoelectric performances in the intermediate temperature range (up to about 600 °C). Mg2Si is typically produced with powder processing by Spark Plasma Sintering (SPS), partially limiting its widespread diffusion also due to the costly production technique. Here we present a simple route to sinter Mg2Si pressed powders by UHS. The process allowed to obtain dense samples (with relative densities >95%) with 20 s heating up to about 1080 °C followed by a rapid free cooling, a total thermal history below 1 min, and with energy demand at the Wh scale. The high process rate proved its efficacy in preventing grain growth and in avoiding any significant Mg evaporation. A full thermoelectric functional characterization is presented for Mg2Si and Bi-doped Mg2Si, together with a comparison with SPS-produced properties.
Agglomerated serum albumin adsorbed protocatechuic acid coated superparamagnetic iron oxide nanoparticles as a theranostic agent
Authors: Bozoglu Serdar , Arvas Melih Besir , Varlı Hanife Sevgi , Ucar Burcu , Acar Tayfun , Karatepe Nilgün
Published: January 2023

Iron oxide nanoparticles have been one of the most widely used nanomaterials in biomedical applications. However, the incomplete understanding of the toxicity mechanisms limits their use in diagnosis and treatment processes. Many parameters are associated with their toxicity such as size, surface modification, solubility, concentration and immunogenicity. Further research needs to be done to address toxicity-related concerns and to increase its effectiveness in various applications. Herein, colloidally stable nanoparticles were prepared by coating magnetic iron oxide nanoparticles (MIONPs) with protocatechuic acid (PCA) which served as a stabilizer and a linkage for a further functional layer. A new perfusion agent with magnetic imaging capability was produced by the adsorption of biocompatible passivating agent macro-aggregated albumin (MAA) on the PCA-coated MIONPs. PCA-coated MIONPs were investigated using infrared spectroscopy, thermogravimetric analysis and dynamic light scattering while adsorption of MAA was analysed by transmission electron microscopy, Fourier-transform infrared spectroscopy and x-ray diffraction methods. Magnetic measurements of samples indicated that all samples showed superparamagnetic behaviour. Cytotoxicity results revealed that the adsorption of MAA onto PCA-coated MIONPs provided an advantage by diminishing their toxicity against the L929 mouse fibroblast cell line compared to bare Fe3O4.
Topologically preserved registration of 3D CT images with deep networks
Authors: Liu Huaying , Gong Guanzhong , Zou Wei , Hu Nan , Wang Jiajun
Published: January 2023

Objective. Computed Tomography (CT) image registration makes fast and accurate imaging-based disease diagnosis possible. We aim to develop a framework which can perform accurate local registration of organs in 3D CT images while preserving the topology of transformation. Approach. In this framework, the Faster R-CNN method is first used to detect local areas containing organs from fixed and moving images whose results are then registered with a weakly supervised deep neural network. In this network, a novel 3D channel coordinate attention (CA) module is introduced to reduce the loss of position information. The image edge loss and the organ labelling loss are used to weakly supervise the training process of our deep network, which enables the network learning to focus on registering organs and image structures. An intuitive inverse module is also used to reduce the folding of deformation field. More specifically, the folding is suppressed directly by simultaneously maximizing forward and backward registration accuracy in the image domain rather than indirectly by measuring the consistency of forward and inverse deformation fields as usual. Main results. Our method achieves an average dice similarity coefficient (DSC) of 0.954 and an average Similarity (Sim) of 0.914 on publicly available liver datasets (LiTS for training and Sliver07 for testing) and achieves an average DSC of 0.914 and an average Sim of 0.947 on our home-built left ventricular myocardium (LVM) dataset. Significance. Experimental results show that our proposed method can significantly improve the registration accuracy of organs such as the liver and LVM. Moreover, our inverse module can intuitively improve the inherent topological preservation of transformations.
Cross-convolutional transformer for automated multi-organs segmentation in a variety of medical images
Authors: Wang Jing , Zhao Haiyue , Liang Wei , Wang Shuyu , Zhang Yan
Published: January 2023

Objective. It is a huge challenge for multi-organs segmentation in various medical images based on a consistent algorithm with the development of deep learning methods. We therefore develop a deep learning method based on cross-convolutional transformer for these automated- segmentation to obtain better generalization and accuracy. Approach. We propose a cross-convolutional transformer network (C2Former) to solve the segmentation problem. Specifically, we first redesign a novel cross-convolutional self-attention mechanism in terms of the algorithm to integrate local and global contexts and model long-distance and short-distance dependencies to enhance the semantic feature understanding of images. Then multi-scale feature edge fusion module is proposed to combine the image edge features, which effectively form multi-scale feature streams and establish reliable relational connections in the global context. Finally, we use three different modalities, imaging three different anatomical regions to train and test multi organs and evaluate segmentation performance. Main results. We use the evaluation metrics of Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95) for each dataset. Experiments showed the average DSC of 83.22% and HD95 of 17.55 mm on the Synapse dataset (CT images of abdominal multi-organ), the average DSC of 91.42% and HD95 of 1.06 mm on the ACDC dataset (MRI of cardiac substructures) and the average DSC of 86.78% and HD95 of 16.85 mm on the ISIC 2017 dataset (skin cancer images). In each dataset, our proposed method consistently outperforms the compared networks. Significance. The proposed deep learning network provides a generalized and accurate solution method for multi-organ segmentation in the three different datasets. It has the potential to be applied to a variety of medical datasets for structural segmentation.
The effect of longitudinal static magnetic field on the radiation efficiency of high harmonics from overdense plasma
Authors: Wu Yanbo , Xu Xinrong , Li Qianni , Zou Debin , Zhang Yuxue , Yin Yan , Liu Ke , Yu TongPu
Published: January 2023

The effect of the magnetic field applied along the laser propagation direction on the radiation efficiency of high-order harmonics generated from laser-irradiated overdense plasma is investigated theoretically and numerically. We find that the external magnetic field can increase the transmittance of the overdense target, thereby dramatically enhancing the energy coupling between the laser and target. While for high-order harmonics of the laser reflected from the oscillating target, the radiation efficiency reaches the maximum when the cyclotron frequency of the electrons in the magnetized target approaches the laser frequency. This conclusion applies only to overdense plasmas targets. For targets with low reflectivity, the application of the magnetic field reduces the harmonic radiation efficiency due to the decrease of both the oscillating coherence and opacity of the target. This work provides a reasonable approach to improving the radiation efficiency of high-order harmonics and a method to estimate the magnitude of the self-generated magnetic field during intense laser–plasma interactions.
Nonlinear second order electromagnetic gyrokinetic theory for a tokamak plasma
Authors: Dudkovskaia A V , Wilson H R , Connor J W , Dickinson D , Parra F I
Published: January 2023

The steep plasma pressure gradient that forms at the edge of the high confinement, H-mode regime of tokamak operation provides free energy to drive electromagnetic micro-instabilities that are widely believed to influence the transport processes in this so-called pedestal region. This high pressure gradient also provides a high current density (bootstrap current), known to influence ballooning mode stability and to be important for driving kink modes in the ideal magneto-hydrodynamic plasma model (so-called peeling-ballooning modes). Furthermore, efficient, steady state future tokamak power plants must operate with a large bootstrap current in the core and especially concerning spherical tokamaks, confinement will be influenced by electromagnetic turbulence. To accommodate these important situations, conventional electromagnetic gyrokinetic theory is extended to incorporate neoclassical effects in the equilibrium drives, allowing

B

ϑ

∼

B
0

(B
0 is the confining magnetic field, and B

ϑ
is its poloidal component). This provides a global gyrokinetic model that self-consistently captures the consequences of large bootstrap current fractions on the equilibrium distribution functions.
Hyperdoped silicon materials: from basic materials properties to sub-bandgap infrared photodetectors
Authors: Sher Meng-Ju , Hemme Eric García
Published: January 2023

Hyperdoping silicon, which introduces deep-level dopants into Si at concentrations near one atomic percent, drastically changes its optoelectronic properties. We review recent progress in the fundamental understanding of the material properties and state of the art sub-bandgap infrared photodetectors. Different hyperdoping techniques are reviewed and compared, namely ion implantation followed by pulsed laser melting (PLM) or other fast annealing methods and PLM of Si with a dopant precursor. We review data available in the literature for material properties related to the success of optoelectronic devices such as the charge carrier lifetime, mobility, and sub-bandgap light absorption of hyperdoped Si with different dopants. To maximize carrier generation and collection efficiency in a sub-bandgap photodetector, charge carrier lifetimes must be long enough to be transported through the hyperdoped layer, which should be on the order of light absorption depth. Lastly, the charge transport properties and photodetector responsivities of hyperdoped Si based photodiodes at room temperature and at cryogenic temperatures are compared. The charge carrier transport mechanisms at different temperature ranges and in different dopant systems are discussed. At room temperature, despite different dopant energetics and hyperdoped thicknesses, light detection exhibits similar spectral responsivities with a common cutoff around 0.5 eV, and at low temperatures, it extends further into the infrared range. The roles of the dopant energetics and process-induced defects are discussed. We highlight future material development directions for enhancing device performance.
Fabrication, characterization, and gas sensing performance of chromium doped WO3 nanoflakes
Authors: Kılıç Alp , Tekin Büşra , Alev Onur , Özdemir Okan , Colakerol Arslan Leyla , Büyükköse Serkan , Özturk Zafer Ziya
Published: January 2023

Pristine and chromium (Cr) doped WO3 nanoflakes (NFs) with various concentrations were successfully fabricated by a facile hydrothermal technique on alumina (Al2O3) substrates. The structural, optical, and morphological properties of these NFs were investigated by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Visible diffusion reflectance spectroscopy (UV–Vis DRS), and x-ray photoelectron spectroscopy. Gas sensor tests were performed against various volatile organic compounds such as ethanol, xylene, toluene, and isopropanol gases in the temperature range between 50 °C and 250 °C. According to the results of these tests, the isopropanol sensing ability of WO3 NFs is enhanced with Cr-doping due to the increasing active adsorption sites on the surface and improved surface reactions with the decreasing band gap energy. The highest isopropanol sensing response which was calculated to be 77.1 has been obtained by nominally 2% Cr doping at the optimal operating temperature of 150 °C.
Theoretical and experimental study on performance of compound-driven MR valve-controlled damper
Authors: Sun Anxin , Xie Fangwei , Yu Xinshi , Shi Xiuwei , Ji Jinjie , Gao Yonghua , He Kewei
Published: January 2023

A compound-driven magnetorheological (MR) valve is designed to cope with the low reliability and high energy consumption of traditional MR valves. The operating magnetic field of the valve is applied by both the excitation coil and ring magnet, maintaining excellent pressure drop performance even at zero current. To analyze the performance and obtain the variation law of the magnetic flux density and pressure drop, a pressure drop mathematical model and a magnetic field simulation model are established. The key parameters of the MR valve are also optimized using non-dominated sorting genetic algorithms-II. A dynamic performance test system is built, and the influence of the load on the pressure drop and hysteresis characteristics of the MR valve is studied. The results show that the optimized pressure drop and adjustable coefficient are improved by 4.7% and 8.6% respectively. The pressure drop grows nonlinearly with the electric current and reaches saturation at a current of 1.5 A, and a pressure drop of 1485 kPa is still generated at zero current. The output damping force of the compound-driven MR valve-controlled damper can be continuously adjustable, indicating that the dynamic performance of the damper can be controlled by adjusting the input current.
A theoretical study of the improved CO oxidation on WC supported Au monolayer by Cu doping
Authors: Chang Qingfang , Zhang Xilin , Yang Zongxian
Published: January 2023

Metal monolayer supported on tungsten carbides have received considerable attention in the field of catalysis, while the adsorption properties of reactants need to be optimized to improve the catalytic activity further. Alloy monolayers on tungsten carbides can deliver different geometric and electronic characters from pure metal layers, owing to the change in local environments. Herein, using the first-principles calculations, the CO oxidation processes on the supported CuAu alloy monolayer on tungsten carbide are systematically investigated and compared with that on pure metal monolayers. It is found that introducing Cu dopant in Au monolayer will elevate the d-band center of the formed alloy monolayer and thus enhancing the adsorption of reactants around the Cu atom, which is caused by the charge redistribution. Especially, the unbalanced interaction strength between Cu-O and Au-O promotes the rotation and migration of oxygen atom to interact with the C atom of CO, which lowers the energy barriers for the formation and dissociation of OOCO intermediate. The oxidation of CO by an atomic O with the largest energy barrier of 0.27 eV along the Langmuir-Hinshelwood pathway is identified as the rate determining step, which is superior or comparable to the reported CO oxidation catalysts. The significance of alloy monolayer on tungsten carbides are further highlighted by comparing the adsorption energy and reaction barrier of rate-limiting step on the pure metal monolayers. This work is insightful for the rational design of highly efficient catalysts based on alloy systems.
Simulation of bulk and grain boundary diffusion phenomena in a high entropy CoCrFeMnNi alloy by molecular dynamics
Authors: Junhong Fan , Weiqiang Zhang
Published: January 2023

A series of calculations on the self-diffusion behavior of high entropy CoCrFeMnNi alloy were carried out using molecular dynamics methods. By computing both vacancy formation energy and atomic migration energy of the constituent elements in the alloy, the diffusional activation energy of each element is obtained, and the self-diffusion coefficients for bulk diffusion were calculated, with the values exhibiting close to of experiments. A model for structures of symmetrically tilted grain boundary is established, with Σ9 and Σ27 grain boundaries studied based on the coincidence site lattice theory. Measured by the full width at half maxima of the radial distribution function, it is found that the grain boundaries with low index are more ordered than those with high plane index, and the atom fluctuation occurred in the low-indexed grain boundaries is less intensively and sensitively to temperature change. Meanwhile, the diffusion coefficients of ordered grain boundaries are generally smaller than those of disordered grain boundaries. Compared with the experimental values of grain boundary diffusion, the diffusion activation energy of configured grain boundaries from coincidence site lattice is smaller than that of normal large-angle grain boundaries.
Correlation between speed and turning naturally arises for sparsely sampled cell movements
Authors: Ganusov Vitaly V , Zenkov Viktor S , Majumder Barun
Published: January 2023

Mechanisms regulating cell movement are not fully understood. One feature of cell movement that determines how far cells displace from an initial position is persistence, the ability to perform movements in a direction similar to the previous movement direction. Persistence is thus determined by turning angles (TA) between two sequential displacements and can be characterized by an average TA or persistence time. Recent studies documenting T cell movement in zebrafish found that a cell’s average speed and average TA are negatively correlated, suggesting a fundamental cell-intrinsic program whereby cells with a lower TA (and larger persistence time) are intrinsically faster (or faster cells turn less). In this paper we confirm the existence of the correlation between turning and speed for six different datasets on 3D movement of CD8 T cells in murine lymph nodes or liver. Interestingly, the negative correlation between TA and speed was observed in experiments in which liver-localized CD8 T cells rapidly displace due to floating with the blood flow, suggesting that other mechanisms besides cell-intrinsic program may be at play. By simulating correlated random walks using two different frameworks (one based on the von Mises–Fisher (vMF) distribution and another based on the Ornstein–Uhlenbeck (OU) process) we show that the negative correlation between speed and turning naturally arises when cell trajectories are sub-sampled, i.e. when the frequency of sampling is lower than frequency at which cells typically make movements. This effect is strongest when the sampling frequency is of the order of magnitude of the inverse of persistence time of cells and when cells vary in persistence time. The effect arises in part due to the sensitivity of estimated cell speeds to the frequency of imaging whereby less frequent imaging results in slower speeds. Interestingly, by using estimated persistence times for cells in two of our datasets and simulating cell movements using the OU process, we could partially reproduce the experimentally observed correlation between TA and speed without a cell-intrinsic program linking the two processes. Our results thus suggest that sub-sampling may contribute to (and perhaps fully explains) the observed correlation between speed and turning at least for some cell trajectory data and emphasize the role of sampling frequency in the inference of critical cellular parameters of cell motility such as speeds.
Five-year Monitoring of 225 GHz Opacity at Thule Air Base (Pituffik), Greenland
Authors: Matsushita Satoki , Martin-Cocher Pierre L. , Paine Scott N. , Huang Chih-Wei L. , Patel Nimesh A. , Asada Keiichi , Chen Ming-Tang , Ho Paul T. P. , Inoue Makoto , Koch Patrick M. , Norton Timothy
Published: January 2023

We present five-year monitoring results of 225 GHz zenith opacity using a tipping radiometer at Thule Air Base (Pituffik), Greenland, where the Greenland Telescope is currently located. The site shows a clear seasonal variation with average opacity lower by a factor of two during winter compared with summer, similar to Greenland Summit. The 25%, 50%, and 75% quartiles of the 225 GHz opacity during the winter months of November through April are 0.14, 0.17, and 0.22, respectively. These values are three times larger than those at the Greenland Summit, and the astronomical observing efficiency in this band is about an order of magnitude better at the Summit than at the Thule Air Base. 225 GHz opacity continuously less than 0.2 for 100–200 hr (i.e., for about a week) occurs about 20 times per year, and on several occasions it even reaches up to 300–400 hr (i.e., about two weeks). These statistics indicate that Thule is a very good site for millimeter astronomy that needs very stable opacity conditions, such as continuum camera observations or VLBI observations that span over several days. Estimated transmission spectra in the winter season show that most of the time (75% quartile) observations at frequencies below 300 GHz are possible with modest atmospheric attenuation (opacities < 0.5), and at frequencies below 350 GHz for a quarter of the time. Although the atmospheric transmission is low (only up to ∼20%), the 650 GHz and 850 GHz windows are also accessible for 5% of the wintertime. For about 50% of the summertime, it is possible to observe around the frequency of 220 GHz, which overlaps with the current EHT observation frequency of 221.1 GHz, with modest atmospheric attenuation (opacities < 0.5). On the other hand, the 350 GHz window is very difficult to observe in the summertime.
Alignment sensitivity of molecular-frame photoelectron momentum and angular distribution of

H2+

by XUV attosecond pulses
Authors: Liu Xiaoyu , Gao Shan , Wang Ningyue , Zhu Fengzheng , Jiao Liguang , Liu Aihua
Published: January 2023

In this work, we investigate the molecular-frame photoelectron momentum and angular distributions (MF-PMD and MF-PAD) of

H

2

+

in the presence of XUV Attosecond Pulses. We present the alignment-sensitive effect of MF-PMDs and MF-PADs when the laser field polarization and the molecular axis are close to parallel geometry. Our results show that the MF-PADs and MF-PMDs of single-photon ionization of

H

2

+

ion vary drastically when the alignment slightly shifts from parallel geometry to a small alignment angle (e.g. 4°) between the laser polarization direction and the molecular axis at the equilibrium inter-nuclear distance of R

c
= 2 atomic units. As R

c
increases to 4 atomic units, such sensitivity is decreased. The R

c
-dependent transition cross-sections in different channels are found to be the origin of such sensitivity.